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/linux-master/arch/powerpc/platforms/cell/spufs/
H A Dinode.cdiff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff de6cc651 Mon May 27 00:55:02 MDT 2019 Thomas Gleixner <tglx@linutronix.de> treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 153

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 or at your option any
later version this program is distributed in the hope that it will
be useful but without any warranty without even the implied warranty
of merchantability or fitness for a particular purpose see the gnu
general public license for more details you should have received a
copy of the gnu general public license along with this program if
not write to the free software foundation inc 675 mass ave cambridge
ma 02139 usa

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 77 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Armijn Hemel <armijn@tjaldur.nl>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.837555891@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff 2c3e4787 Wed Jul 02 19:42:20 MDT 2008 Jeremy Kerr <jk@ozlabs.org> powerpc/spufs: only add ".ctx" file with "debug" mount option

Currently, the .ctx debug file in spu context directories is always
present.

We'd prefer to prevent users from relying on this file, so add a
"debug" mount option to spufs. The .ctx file will only be added to
the context directories when this option is present.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
diff ccf17e9d Mon Apr 23 13:08:29 MDT 2007 Jeremy Kerr <jk@ozlabs.org> [POWERPC] spu_base: fix initialisation on systems with no SPEs

This change fixes the case where spu_base and spufs are initialised on a
system with no SPEs - unconditionally create the spu_lists so spu_alloc
doesn't explode, and check for spu_management ops before starting spufs.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>

arch/powerpc/platforms/cell/spu_base.c | 7 ++++---
arch/powerpc/platforms/cell/spufs/inode.c | 5 +++++
2 files changed, 9 insertions(+), 3 deletions(-)
diff 5dfe4c96 Mon Feb 12 01:55:31 MST 2007 Arjan van de Ven <arjan@linux.intel.com> [PATCH] mark struct file_operations const 2

Many struct file_operations in the kernel can be "const". Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data. In addition it'll catch accidental writes at compile time to
these shared resources.

[akpm@osdl.org: sparc64 fix]
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff e18b890b Wed Dec 06 21:33:20 MST 2006 Christoph Lameter <clameter@sgi.com> [PATCH] slab: remove kmem_cache_t

Replace all uses of kmem_cache_t with struct kmem_cache.

The patch was generated using the following script:

#!/bin/sh
#
# Replace one string by another in all the kernel sources.
#

set -e

for file in `find * -name "*.c" -o -name "*.h"|xargs grep -l $1`; do
quilt add $file
sed -e "1,\$s/$1/$2/g" $file >/tmp/$$
mv /tmp/$$ $file
quilt refresh
done

The script was run like this

sh replace kmem_cache_t "struct kmem_cache"

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
/linux-master/drivers/base/
H A Ddevtmpfs.cdiff 5cdc03c5 Wed Feb 01 20:32:01 MST 2023 Longlong Xia <xialonglong1@huawei.com> devtmpfs: convert to pr_fmt

Use the pr_fmt() macro to prefix all the output with "devtmpfs: ".
while at it, convert printk(<LEVEL>) to pr_<level>().

Signed-off-by: Longlong Xia <xialonglong1@huawei.com>
Link: https://lore.kernel.org/r/20230202033203.1239239-2-xialonglong1@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff 01085e24 Fri Mar 12 03:30:27 MST 2021 Rasmus Villemoes <linux@rasmusvillemoes.dk> devtmpfs: actually reclaim some init memory

Currently gcc seems to inline devtmpfs_setup() into devtmpfsd(), so
its memory footprint isn't reclaimed as intended. Mark it noinline to
make sure it gets put in .init.text.

While here, setup_done can also be put in .init.data: After complete()
releases the internal spinlock, the completion object is never touched
again by that thread, and the waiting thread doesn't proceed until it
observes ->done while holding that spinlock.

This is now the same pattern as for kthreadd_done in init/main.c:
complete() is done in a __ref function, while the corresponding
wait_for_completion() is in an __init function.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Link: https://lore.kernel.org/r/20210312103027.2701413-2-linux@rasmusvillemoes.dk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff c9d6b287 Wed Jan 15 11:41:49 MST 2020 Rasmus Villemoes <linux@rasmusvillemoes.dk> devtmpfs: fix theoretical stale pointer deref in devtmpfsd()

After complete(&setup_done), devtmpfs_init proceeds and may actually
return, invalidating the *err pointer, before devtmpfsd() proceeds to
reading back *err.

This is of course completely theoretical since the error conditions
never trigger in practice, and even if they did, nobody cares about
the exit value from a kernel thread, so it doesn't matter if we happen
to read back some garbage from some other stack frame. Still, this
isn't a pattern that should be copy-pasted, so fix it.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Link: https://lore.kernel.org/r/20200115184154.3492-2-linux@rasmusvillemoes.dk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff e262e32d Thu Nov 01 17:07:23 MDT 2018 David Howells <dhowells@redhat.com> vfs: Suppress MS_* flag defs within the kernel unless explicitly enabled

Only the mount namespace code that implements mount(2) should be using the
MS_* flags. Suppress them inside the kernel unless uapi/linux/mount.h is
included.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: David Howells <dhowells@redhat.com>
diff b2441318 Wed Nov 01 08:07:57 MDT 2017 Greg Kroah-Hartman <gregkh@linuxfoundation.org> License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff b2441318 Wed Nov 01 08:07:57 MDT 2017 Greg Kroah-Hartman <gregkh@linuxfoundation.org> License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff a528d35e Tue Jan 31 09:46:22 MST 2017 David Howells <dhowells@redhat.com> statx: Add a system call to make enhanced file info available

Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.

The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode. This change is propagated to the vfs_getattr*()
function.

Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.

========
OVERVIEW
========

The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preference proved to be for a new syscall
with an extended stat structure.

A number of requests were gathered for features to be included. The
following have been included:

(1) Make the fields a consistent size on all arches and make them large.

(2) Spare space, request flags and information flags are provided for
future expansion.

(3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
__s64).

(4) Creation time: The SMB protocol carries the creation time, which could
be exported by Samba, which will in turn help CIFS make use of
FS-Cache as that can be used for coherency data (stx_btime).

This is also specified in NFSv4 as a recommended attribute and could
be exported by NFSD [Steve French].

(5) Lightweight stat: Ask for just those details of interest, and allow a
netfs (such as NFS) to approximate anything not of interest, possibly
without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
Dilger] (AT_STATX_DONT_SYNC).

(6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
its cached attributes are up to date [Trond Myklebust]
(AT_STATX_FORCE_SYNC).

And the following have been left out for future extension:

(7) Data version number: Could be used by userspace NFS servers [Aneesh
Kumar].

Can also be used to modify fill_post_wcc() in NFSD which retrieves
i_version directly, but has just called vfs_getattr(). It could get
it from the kstat struct if it used vfs_xgetattr() instead.

(There's disagreement on the exact semantics of a single field, since
not all filesystems do this the same way).

(8) BSD stat compatibility: Including more fields from the BSD stat such
as creation time (st_btime) and inode generation number (st_gen)
[Jeremy Allison, Bernd Schubert].

(9) Inode generation number: Useful for FUSE and userspace NFS servers
[Bernd Schubert].

(This was asked for but later deemed unnecessary with the
open-by-handle capability available and caused disagreement as to
whether it's a security hole or not).

(10) Extra coherency data may be useful in making backups [Andreas Dilger].

(No particular data were offered, but things like last backup
timestamp, the data version number and the DOS archive bit would come
into this category).

(11) Allow the filesystem to indicate what it can/cannot provide: A
filesystem can now say it doesn't support a standard stat feature if
that isn't available, so if, for instance, inode numbers or UIDs don't
exist or are fabricated locally...

(This requires a separate system call - I have an fsinfo() call idea
for this).

(12) Store a 16-byte volume ID in the superblock that can be returned in
struct xstat [Steve French].

(Deferred to fsinfo).

(13) Include granularity fields in the time data to indicate the
granularity of each of the times (NFSv4 time_delta) [Steve French].

(Deferred to fsinfo).

(14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags.
Note that the Linux IOC flags are a mess and filesystems such as Ext4
define flags that aren't in linux/fs.h, so translation in the kernel
may be a necessity (or, possibly, we provide the filesystem type too).

(Some attributes are made available in stx_attributes, but the general
feeling was that the IOC flags were to ext[234]-specific and shouldn't
be exposed through statx this way).

(15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
Michael Kerrisk].

(Deferred, probably to fsinfo. Finding out if there's an ACL or
seclabal might require extra filesystem operations).

(16) Femtosecond-resolution timestamps [Dave Chinner].

(A __reserved field has been left in the statx_timestamp struct for
this - if there proves to be a need).

(17) A set multiple attributes syscall to go with this.

===============
NEW SYSTEM CALL
===============

The new system call is:

int ret = statx(int dfd,
const char *filename,
unsigned int flags,
unsigned int mask,
struct statx *buffer);

The dfd, filename and flags parameters indicate the file to query, in a
similar way to fstatat(). There is no equivalent of lstat() as that can be
emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is
also no equivalent of fstat() as that can be emulated by passing a NULL
filename to statx() with the fd of interest in dfd.

Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):

(1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
respect.

(2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
its attributes with the server - which might require data writeback to
occur to get the timestamps correct.

(3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
network filesystem. The resulting values should be considered
approximate.

mask is a bitmask indicating the fields in struct statx that are of
interest to the caller. The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat(). It should be noted that asking for
more information may entail extra I/O operations.

buffer points to the destination for the data. This must be 256 bytes in
size.

======================
MAIN ATTRIBUTES RECORD
======================

The following structures are defined in which to return the main attribute
set:

struct statx_timestamp {
__s64 tv_sec;
__s32 tv_nsec;
__s32 __reserved;
};

struct statx {
__u32 stx_mask;
__u32 stx_blksize;
__u64 stx_attributes;
__u32 stx_nlink;
__u32 stx_uid;
__u32 stx_gid;
__u16 stx_mode;
__u16 __spare0[1];
__u64 stx_ino;
__u64 stx_size;
__u64 stx_blocks;
__u64 __spare1[1];
struct statx_timestamp stx_atime;
struct statx_timestamp stx_btime;
struct statx_timestamp stx_ctime;
struct statx_timestamp stx_mtime;
__u32 stx_rdev_major;
__u32 stx_rdev_minor;
__u32 stx_dev_major;
__u32 stx_dev_minor;
__u64 __spare2[14];
};

The defined bits in request_mask and stx_mask are:

STATX_TYPE Want/got stx_mode & S_IFMT
STATX_MODE Want/got stx_mode & ~S_IFMT
STATX_NLINK Want/got stx_nlink
STATX_UID Want/got stx_uid
STATX_GID Want/got stx_gid
STATX_ATIME Want/got stx_atime{,_ns}
STATX_MTIME Want/got stx_mtime{,_ns}
STATX_CTIME Want/got stx_ctime{,_ns}
STATX_INO Want/got stx_ino
STATX_SIZE Want/got stx_size
STATX_BLOCKS Want/got stx_blocks
STATX_BASIC_STATS [The stuff in the normal stat struct]
STATX_BTIME Want/got stx_btime{,_ns}
STATX_ALL [All currently available stuff]

stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.

Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution. Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.

The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does. The following
attributes map to FS_*_FL flags and are the same numerical value:

STATX_ATTR_COMPRESSED File is compressed by the fs
STATX_ATTR_IMMUTABLE File is marked immutable
STATX_ATTR_APPEND File is append-only
STATX_ATTR_NODUMP File is not to be dumped
STATX_ATTR_ENCRYPTED File requires key to decrypt in fs

Within the kernel, the supported flags are listed by:

KSTAT_ATTR_FS_IOC_FLAGS

[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]

New flags include:

STATX_ATTR_AUTOMOUNT Object is an automount trigger

These are for the use of GUI tools that might want to mark files specially,
depending on what they are.

Fields in struct statx come in a number of classes:

(0) stx_dev_*, stx_blksize.

These are local system information and are always available.

(1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
stx_size, stx_blocks.

These will be returned whether the caller asks for them or not. The
corresponding bits in stx_mask will be set to indicate whether they
actually have valid values.

If the caller didn't ask for them, then they may be approximated. For
example, NFS won't waste any time updating them from the server,
unless as a byproduct of updating something requested.

If the values don't actually exist for the underlying object (such as
UID or GID on a DOS file), then the bit won't be set in the stx_mask,
even if the caller asked for the value. In such a case, the returned
value will be a fabrication.

Note that there are instances where the type might not be valid, for
instance Windows reparse points.

(2) stx_rdev_*.

This will be set only if stx_mode indicates we're looking at a
blockdev or a chardev, otherwise will be 0.

(3) stx_btime.

Similar to (1), except this will be set to 0 if it doesn't exist.

=======
TESTING
=======

The following test program can be used to test the statx system call:

samples/statx/test-statx.c

Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.

Here's some example output. Firstly, an NFS directory that crosses to
another FSID. Note that the AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.

[root@andromeda ~]# /tmp/test-statx -A /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:26 Inode: 1703937 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)

Secondly, the result of automounting on that directory.

[root@andromeda ~]# /tmp/test-statx /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:27 Inode: 2 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff a528d35e Tue Jan 31 09:46:22 MST 2017 David Howells <dhowells@redhat.com> statx: Add a system call to make enhanced file info available

Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.

The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode. This change is propagated to the vfs_getattr*()
function.

Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.

========
OVERVIEW
========

The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preference proved to be for a new syscall
with an extended stat structure.

A number of requests were gathered for features to be included. The
following have been included:

(1) Make the fields a consistent size on all arches and make them large.

(2) Spare space, request flags and information flags are provided for
future expansion.

(3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
__s64).

(4) Creation time: The SMB protocol carries the creation time, which could
be exported by Samba, which will in turn help CIFS make use of
FS-Cache as that can be used for coherency data (stx_btime).

This is also specified in NFSv4 as a recommended attribute and could
be exported by NFSD [Steve French].

(5) Lightweight stat: Ask for just those details of interest, and allow a
netfs (such as NFS) to approximate anything not of interest, possibly
without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
Dilger] (AT_STATX_DONT_SYNC).

(6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
its cached attributes are up to date [Trond Myklebust]
(AT_STATX_FORCE_SYNC).

And the following have been left out for future extension:

(7) Data version number: Could be used by userspace NFS servers [Aneesh
Kumar].

Can also be used to modify fill_post_wcc() in NFSD which retrieves
i_version directly, but has just called vfs_getattr(). It could get
it from the kstat struct if it used vfs_xgetattr() instead.

(There's disagreement on the exact semantics of a single field, since
not all filesystems do this the same way).

(8) BSD stat compatibility: Including more fields from the BSD stat such
as creation time (st_btime) and inode generation number (st_gen)
[Jeremy Allison, Bernd Schubert].

(9) Inode generation number: Useful for FUSE and userspace NFS servers
[Bernd Schubert].

(This was asked for but later deemed unnecessary with the
open-by-handle capability available and caused disagreement as to
whether it's a security hole or not).

(10) Extra coherency data may be useful in making backups [Andreas Dilger].

(No particular data were offered, but things like last backup
timestamp, the data version number and the DOS archive bit would come
into this category).

(11) Allow the filesystem to indicate what it can/cannot provide: A
filesystem can now say it doesn't support a standard stat feature if
that isn't available, so if, for instance, inode numbers or UIDs don't
exist or are fabricated locally...

(This requires a separate system call - I have an fsinfo() call idea
for this).

(12) Store a 16-byte volume ID in the superblock that can be returned in
struct xstat [Steve French].

(Deferred to fsinfo).

(13) Include granularity fields in the time data to indicate the
granularity of each of the times (NFSv4 time_delta) [Steve French].

(Deferred to fsinfo).

(14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags.
Note that the Linux IOC flags are a mess and filesystems such as Ext4
define flags that aren't in linux/fs.h, so translation in the kernel
may be a necessity (or, possibly, we provide the filesystem type too).

(Some attributes are made available in stx_attributes, but the general
feeling was that the IOC flags were to ext[234]-specific and shouldn't
be exposed through statx this way).

(15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
Michael Kerrisk].

(Deferred, probably to fsinfo. Finding out if there's an ACL or
seclabal might require extra filesystem operations).

(16) Femtosecond-resolution timestamps [Dave Chinner].

(A __reserved field has been left in the statx_timestamp struct for
this - if there proves to be a need).

(17) A set multiple attributes syscall to go with this.

===============
NEW SYSTEM CALL
===============

The new system call is:

int ret = statx(int dfd,
const char *filename,
unsigned int flags,
unsigned int mask,
struct statx *buffer);

The dfd, filename and flags parameters indicate the file to query, in a
similar way to fstatat(). There is no equivalent of lstat() as that can be
emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is
also no equivalent of fstat() as that can be emulated by passing a NULL
filename to statx() with the fd of interest in dfd.

Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):

(1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
respect.

(2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
its attributes with the server - which might require data writeback to
occur to get the timestamps correct.

(3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
network filesystem. The resulting values should be considered
approximate.

mask is a bitmask indicating the fields in struct statx that are of
interest to the caller. The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat(). It should be noted that asking for
more information may entail extra I/O operations.

buffer points to the destination for the data. This must be 256 bytes in
size.

======================
MAIN ATTRIBUTES RECORD
======================

The following structures are defined in which to return the main attribute
set:

struct statx_timestamp {
__s64 tv_sec;
__s32 tv_nsec;
__s32 __reserved;
};

struct statx {
__u32 stx_mask;
__u32 stx_blksize;
__u64 stx_attributes;
__u32 stx_nlink;
__u32 stx_uid;
__u32 stx_gid;
__u16 stx_mode;
__u16 __spare0[1];
__u64 stx_ino;
__u64 stx_size;
__u64 stx_blocks;
__u64 __spare1[1];
struct statx_timestamp stx_atime;
struct statx_timestamp stx_btime;
struct statx_timestamp stx_ctime;
struct statx_timestamp stx_mtime;
__u32 stx_rdev_major;
__u32 stx_rdev_minor;
__u32 stx_dev_major;
__u32 stx_dev_minor;
__u64 __spare2[14];
};

The defined bits in request_mask and stx_mask are:

STATX_TYPE Want/got stx_mode & S_IFMT
STATX_MODE Want/got stx_mode & ~S_IFMT
STATX_NLINK Want/got stx_nlink
STATX_UID Want/got stx_uid
STATX_GID Want/got stx_gid
STATX_ATIME Want/got stx_atime{,_ns}
STATX_MTIME Want/got stx_mtime{,_ns}
STATX_CTIME Want/got stx_ctime{,_ns}
STATX_INO Want/got stx_ino
STATX_SIZE Want/got stx_size
STATX_BLOCKS Want/got stx_blocks
STATX_BASIC_STATS [The stuff in the normal stat struct]
STATX_BTIME Want/got stx_btime{,_ns}
STATX_ALL [All currently available stuff]

stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.

Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution. Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.

The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does. The following
attributes map to FS_*_FL flags and are the same numerical value:

STATX_ATTR_COMPRESSED File is compressed by the fs
STATX_ATTR_IMMUTABLE File is marked immutable
STATX_ATTR_APPEND File is append-only
STATX_ATTR_NODUMP File is not to be dumped
STATX_ATTR_ENCRYPTED File requires key to decrypt in fs

Within the kernel, the supported flags are listed by:

KSTAT_ATTR_FS_IOC_FLAGS

[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]

New flags include:

STATX_ATTR_AUTOMOUNT Object is an automount trigger

These are for the use of GUI tools that might want to mark files specially,
depending on what they are.

Fields in struct statx come in a number of classes:

(0) stx_dev_*, stx_blksize.

These are local system information and are always available.

(1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
stx_size, stx_blocks.

These will be returned whether the caller asks for them or not. The
corresponding bits in stx_mask will be set to indicate whether they
actually have valid values.

If the caller didn't ask for them, then they may be approximated. For
example, NFS won't waste any time updating them from the server,
unless as a byproduct of updating something requested.

If the values don't actually exist for the underlying object (such as
UID or GID on a DOS file), then the bit won't be set in the stx_mask,
even if the caller asked for the value. In such a case, the returned
value will be a fabrication.

Note that there are instances where the type might not be valid, for
instance Windows reparse points.

(2) stx_rdev_*.

This will be set only if stx_mode indicates we're looking at a
blockdev or a chardev, otherwise will be 0.

(3) stx_btime.

Similar to (1), except this will be set to 0 if it doesn't exist.

=======
TESTING
=======

The following test program can be used to test the statx system call:

samples/statx/test-statx.c

Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.

Here's some example output. Firstly, an NFS directory that crosses to
another FSID. Note that the AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.

[root@andromeda ~]# /tmp/test-statx -A /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:26 Inode: 1703937 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)

Secondly, the result of automounting on that directory.

[root@andromeda ~]# /tmp/test-statx /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:27 Inode: 2 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff a528d35e Tue Jan 31 09:46:22 MST 2017 David Howells <dhowells@redhat.com> statx: Add a system call to make enhanced file info available

Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.

The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode. This change is propagated to the vfs_getattr*()
function.

Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.

========
OVERVIEW
========

The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preference proved to be for a new syscall
with an extended stat structure.

A number of requests were gathered for features to be included. The
following have been included:

(1) Make the fields a consistent size on all arches and make them large.

(2) Spare space, request flags and information flags are provided for
future expansion.

(3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
__s64).

(4) Creation time: The SMB protocol carries the creation time, which could
be exported by Samba, which will in turn help CIFS make use of
FS-Cache as that can be used for coherency data (stx_btime).

This is also specified in NFSv4 as a recommended attribute and could
be exported by NFSD [Steve French].

(5) Lightweight stat: Ask for just those details of interest, and allow a
netfs (such as NFS) to approximate anything not of interest, possibly
without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
Dilger] (AT_STATX_DONT_SYNC).

(6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
its cached attributes are up to date [Trond Myklebust]
(AT_STATX_FORCE_SYNC).

And the following have been left out for future extension:

(7) Data version number: Could be used by userspace NFS servers [Aneesh
Kumar].

Can also be used to modify fill_post_wcc() in NFSD which retrieves
i_version directly, but has just called vfs_getattr(). It could get
it from the kstat struct if it used vfs_xgetattr() instead.

(There's disagreement on the exact semantics of a single field, since
not all filesystems do this the same way).

(8) BSD stat compatibility: Including more fields from the BSD stat such
as creation time (st_btime) and inode generation number (st_gen)
[Jeremy Allison, Bernd Schubert].

(9) Inode generation number: Useful for FUSE and userspace NFS servers
[Bernd Schubert].

(This was asked for but later deemed unnecessary with the
open-by-handle capability available and caused disagreement as to
whether it's a security hole or not).

(10) Extra coherency data may be useful in making backups [Andreas Dilger].

(No particular data were offered, but things like last backup
timestamp, the data version number and the DOS archive bit would come
into this category).

(11) Allow the filesystem to indicate what it can/cannot provide: A
filesystem can now say it doesn't support a standard stat feature if
that isn't available, so if, for instance, inode numbers or UIDs don't
exist or are fabricated locally...

(This requires a separate system call - I have an fsinfo() call idea
for this).

(12) Store a 16-byte volume ID in the superblock that can be returned in
struct xstat [Steve French].

(Deferred to fsinfo).

(13) Include granularity fields in the time data to indicate the
granularity of each of the times (NFSv4 time_delta) [Steve French].

(Deferred to fsinfo).

(14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags.
Note that the Linux IOC flags are a mess and filesystems such as Ext4
define flags that aren't in linux/fs.h, so translation in the kernel
may be a necessity (or, possibly, we provide the filesystem type too).

(Some attributes are made available in stx_attributes, but the general
feeling was that the IOC flags were to ext[234]-specific and shouldn't
be exposed through statx this way).

(15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
Michael Kerrisk].

(Deferred, probably to fsinfo. Finding out if there's an ACL or
seclabal might require extra filesystem operations).

(16) Femtosecond-resolution timestamps [Dave Chinner].

(A __reserved field has been left in the statx_timestamp struct for
this - if there proves to be a need).

(17) A set multiple attributes syscall to go with this.

===============
NEW SYSTEM CALL
===============

The new system call is:

int ret = statx(int dfd,
const char *filename,
unsigned int flags,
unsigned int mask,
struct statx *buffer);

The dfd, filename and flags parameters indicate the file to query, in a
similar way to fstatat(). There is no equivalent of lstat() as that can be
emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is
also no equivalent of fstat() as that can be emulated by passing a NULL
filename to statx() with the fd of interest in dfd.

Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):

(1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
respect.

(2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
its attributes with the server - which might require data writeback to
occur to get the timestamps correct.

(3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
network filesystem. The resulting values should be considered
approximate.

mask is a bitmask indicating the fields in struct statx that are of
interest to the caller. The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat(). It should be noted that asking for
more information may entail extra I/O operations.

buffer points to the destination for the data. This must be 256 bytes in
size.

======================
MAIN ATTRIBUTES RECORD
======================

The following structures are defined in which to return the main attribute
set:

struct statx_timestamp {
__s64 tv_sec;
__s32 tv_nsec;
__s32 __reserved;
};

struct statx {
__u32 stx_mask;
__u32 stx_blksize;
__u64 stx_attributes;
__u32 stx_nlink;
__u32 stx_uid;
__u32 stx_gid;
__u16 stx_mode;
__u16 __spare0[1];
__u64 stx_ino;
__u64 stx_size;
__u64 stx_blocks;
__u64 __spare1[1];
struct statx_timestamp stx_atime;
struct statx_timestamp stx_btime;
struct statx_timestamp stx_ctime;
struct statx_timestamp stx_mtime;
__u32 stx_rdev_major;
__u32 stx_rdev_minor;
__u32 stx_dev_major;
__u32 stx_dev_minor;
__u64 __spare2[14];
};

The defined bits in request_mask and stx_mask are:

STATX_TYPE Want/got stx_mode & S_IFMT
STATX_MODE Want/got stx_mode & ~S_IFMT
STATX_NLINK Want/got stx_nlink
STATX_UID Want/got stx_uid
STATX_GID Want/got stx_gid
STATX_ATIME Want/got stx_atime{,_ns}
STATX_MTIME Want/got stx_mtime{,_ns}
STATX_CTIME Want/got stx_ctime{,_ns}
STATX_INO Want/got stx_ino
STATX_SIZE Want/got stx_size
STATX_BLOCKS Want/got stx_blocks
STATX_BASIC_STATS [The stuff in the normal stat struct]
STATX_BTIME Want/got stx_btime{,_ns}
STATX_ALL [All currently available stuff]

stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.

Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution. Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.

The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does. The following
attributes map to FS_*_FL flags and are the same numerical value:

STATX_ATTR_COMPRESSED File is compressed by the fs
STATX_ATTR_IMMUTABLE File is marked immutable
STATX_ATTR_APPEND File is append-only
STATX_ATTR_NODUMP File is not to be dumped
STATX_ATTR_ENCRYPTED File requires key to decrypt in fs

Within the kernel, the supported flags are listed by:

KSTAT_ATTR_FS_IOC_FLAGS

[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]

New flags include:

STATX_ATTR_AUTOMOUNT Object is an automount trigger

These are for the use of GUI tools that might want to mark files specially,
depending on what they are.

Fields in struct statx come in a number of classes:

(0) stx_dev_*, stx_blksize.

These are local system information and are always available.

(1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
stx_size, stx_blocks.

These will be returned whether the caller asks for them or not. The
corresponding bits in stx_mask will be set to indicate whether they
actually have valid values.

If the caller didn't ask for them, then they may be approximated. For
example, NFS won't waste any time updating them from the server,
unless as a byproduct of updating something requested.

If the values don't actually exist for the underlying object (such as
UID or GID on a DOS file), then the bit won't be set in the stx_mask,
even if the caller asked for the value. In such a case, the returned
value will be a fabrication.

Note that there are instances where the type might not be valid, for
instance Windows reparse points.

(2) stx_rdev_*.

This will be set only if stx_mode indicates we're looking at a
blockdev or a chardev, otherwise will be 0.

(3) stx_btime.

Similar to (1), except this will be set to 0 if it doesn't exist.

=======
TESTING
=======

The following test program can be used to test the statx system call:

samples/statx/test-statx.c

Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.

Here's some example output. Firstly, an NFS directory that crosses to
another FSID. Note that the AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.

[root@andromeda ~]# /tmp/test-statx -A /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:26 Inode: 1703937 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)

Secondly, the result of automounting on that directory.

[root@andromeda ~]# /tmp/test-statx /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:27 Inode: 2 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff a528d35e Tue Jan 31 09:46:22 MST 2017 David Howells <dhowells@redhat.com> statx: Add a system call to make enhanced file info available

Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.

The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode. This change is propagated to the vfs_getattr*()
function.

Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.

========
OVERVIEW
========

The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preference proved to be for a new syscall
with an extended stat structure.

A number of requests were gathered for features to be included. The
following have been included:

(1) Make the fields a consistent size on all arches and make them large.

(2) Spare space, request flags and information flags are provided for
future expansion.

(3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
__s64).

(4) Creation time: The SMB protocol carries the creation time, which could
be exported by Samba, which will in turn help CIFS make use of
FS-Cache as that can be used for coherency data (stx_btime).

This is also specified in NFSv4 as a recommended attribute and could
be exported by NFSD [Steve French].

(5) Lightweight stat: Ask for just those details of interest, and allow a
netfs (such as NFS) to approximate anything not of interest, possibly
without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
Dilger] (AT_STATX_DONT_SYNC).

(6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
its cached attributes are up to date [Trond Myklebust]
(AT_STATX_FORCE_SYNC).

And the following have been left out for future extension:

(7) Data version number: Could be used by userspace NFS servers [Aneesh
Kumar].

Can also be used to modify fill_post_wcc() in NFSD which retrieves
i_version directly, but has just called vfs_getattr(). It could get
it from the kstat struct if it used vfs_xgetattr() instead.

(There's disagreement on the exact semantics of a single field, since
not all filesystems do this the same way).

(8) BSD stat compatibility: Including more fields from the BSD stat such
as creation time (st_btime) and inode generation number (st_gen)
[Jeremy Allison, Bernd Schubert].

(9) Inode generation number: Useful for FUSE and userspace NFS servers
[Bernd Schubert].

(This was asked for but later deemed unnecessary with the
open-by-handle capability available and caused disagreement as to
whether it's a security hole or not).

(10) Extra coherency data may be useful in making backups [Andreas Dilger].

(No particular data were offered, but things like last backup
timestamp, the data version number and the DOS archive bit would come
into this category).

(11) Allow the filesystem to indicate what it can/cannot provide: A
filesystem can now say it doesn't support a standard stat feature if
that isn't available, so if, for instance, inode numbers or UIDs don't
exist or are fabricated locally...

(This requires a separate system call - I have an fsinfo() call idea
for this).

(12) Store a 16-byte volume ID in the superblock that can be returned in
struct xstat [Steve French].

(Deferred to fsinfo).

(13) Include granularity fields in the time data to indicate the
granularity of each of the times (NFSv4 time_delta) [Steve French].

(Deferred to fsinfo).

(14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags.
Note that the Linux IOC flags are a mess and filesystems such as Ext4
define flags that aren't in linux/fs.h, so translation in the kernel
may be a necessity (or, possibly, we provide the filesystem type too).

(Some attributes are made available in stx_attributes, but the general
feeling was that the IOC flags were to ext[234]-specific and shouldn't
be exposed through statx this way).

(15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
Michael Kerrisk].

(Deferred, probably to fsinfo. Finding out if there's an ACL or
seclabal might require extra filesystem operations).

(16) Femtosecond-resolution timestamps [Dave Chinner].

(A __reserved field has been left in the statx_timestamp struct for
this - if there proves to be a need).

(17) A set multiple attributes syscall to go with this.

===============
NEW SYSTEM CALL
===============

The new system call is:

int ret = statx(int dfd,
const char *filename,
unsigned int flags,
unsigned int mask,
struct statx *buffer);

The dfd, filename and flags parameters indicate the file to query, in a
similar way to fstatat(). There is no equivalent of lstat() as that can be
emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is
also no equivalent of fstat() as that can be emulated by passing a NULL
filename to statx() with the fd of interest in dfd.

Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):

(1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
respect.

(2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
its attributes with the server - which might require data writeback to
occur to get the timestamps correct.

(3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
network filesystem. The resulting values should be considered
approximate.

mask is a bitmask indicating the fields in struct statx that are of
interest to the caller. The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat(). It should be noted that asking for
more information may entail extra I/O operations.

buffer points to the destination for the data. This must be 256 bytes in
size.

======================
MAIN ATTRIBUTES RECORD
======================

The following structures are defined in which to return the main attribute
set:

struct statx_timestamp {
__s64 tv_sec;
__s32 tv_nsec;
__s32 __reserved;
};

struct statx {
__u32 stx_mask;
__u32 stx_blksize;
__u64 stx_attributes;
__u32 stx_nlink;
__u32 stx_uid;
__u32 stx_gid;
__u16 stx_mode;
__u16 __spare0[1];
__u64 stx_ino;
__u64 stx_size;
__u64 stx_blocks;
__u64 __spare1[1];
struct statx_timestamp stx_atime;
struct statx_timestamp stx_btime;
struct statx_timestamp stx_ctime;
struct statx_timestamp stx_mtime;
__u32 stx_rdev_major;
__u32 stx_rdev_minor;
__u32 stx_dev_major;
__u32 stx_dev_minor;
__u64 __spare2[14];
};

The defined bits in request_mask and stx_mask are:

STATX_TYPE Want/got stx_mode & S_IFMT
STATX_MODE Want/got stx_mode & ~S_IFMT
STATX_NLINK Want/got stx_nlink
STATX_UID Want/got stx_uid
STATX_GID Want/got stx_gid
STATX_ATIME Want/got stx_atime{,_ns}
STATX_MTIME Want/got stx_mtime{,_ns}
STATX_CTIME Want/got stx_ctime{,_ns}
STATX_INO Want/got stx_ino
STATX_SIZE Want/got stx_size
STATX_BLOCKS Want/got stx_blocks
STATX_BASIC_STATS [The stuff in the normal stat struct]
STATX_BTIME Want/got stx_btime{,_ns}
STATX_ALL [All currently available stuff]

stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.

Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution. Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.

The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does. The following
attributes map to FS_*_FL flags and are the same numerical value:

STATX_ATTR_COMPRESSED File is compressed by the fs
STATX_ATTR_IMMUTABLE File is marked immutable
STATX_ATTR_APPEND File is append-only
STATX_ATTR_NODUMP File is not to be dumped
STATX_ATTR_ENCRYPTED File requires key to decrypt in fs

Within the kernel, the supported flags are listed by:

KSTAT_ATTR_FS_IOC_FLAGS

[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]

New flags include:

STATX_ATTR_AUTOMOUNT Object is an automount trigger

These are for the use of GUI tools that might want to mark files specially,
depending on what they are.

Fields in struct statx come in a number of classes:

(0) stx_dev_*, stx_blksize.

These are local system information and are always available.

(1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
stx_size, stx_blocks.

These will be returned whether the caller asks for them or not. The
corresponding bits in stx_mask will be set to indicate whether they
actually have valid values.

If the caller didn't ask for them, then they may be approximated. For
example, NFS won't waste any time updating them from the server,
unless as a byproduct of updating something requested.

If the values don't actually exist for the underlying object (such as
UID or GID on a DOS file), then the bit won't be set in the stx_mask,
even if the caller asked for the value. In such a case, the returned
value will be a fabrication.

Note that there are instances where the type might not be valid, for
instance Windows reparse points.

(2) stx_rdev_*.

This will be set only if stx_mode indicates we're looking at a
blockdev or a chardev, otherwise will be 0.

(3) stx_btime.

Similar to (1), except this will be set to 0 if it doesn't exist.

=======
TESTING
=======

The following test program can be used to test the statx system call:

samples/statx/test-statx.c

Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.

Here's some example output. Firstly, an NFS directory that crosses to
another FSID. Note that the AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.

[root@andromeda ~]# /tmp/test-statx -A /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:26 Inode: 1703937 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)

Secondly, the result of automounting on that directory.

[root@andromeda ~]# /tmp/test-statx /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:27 Inode: 2 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
/linux-master/fs/9p/
H A Dvfs_inode.cdiff 100ccd18 Fri Nov 24 06:39:02 MST 2023 David Howells <dhowells@redhat.com> netfs: Optimise away reads above the point at which there can be no data

Track the file position above which the server is not expected to have any
data (the "zero point") and preemptively assume that we can satisfy
requests by filling them with zeroes locally rather than attempting to
download them if they're over that line - even if we've written data back
to the server. Assume that any data that was written back above that
position is held in the local cache. Note that we have to split requests
that straddle the line.

Make use of this to optimise away some reads from the server. We need to
set the zero point in the following circumstances:

(1) When we see an extant remote inode and have no cache for it, we set
the zero_point to i_size.

(2) On local inode creation, we set zero_point to 0.

(3) On local truncation down, we reduce zero_point to the new i_size if
the new i_size is lower.

(4) On local truncation up, we don't change zero_point.

(5) On local modification, we don't change zero_point.

(6) On remote invalidation, we set zero_point to the new i_size.

(7) If stored data is discarded from the pagecache or culled from fscache,
we must set zero_point above that if the data also got written to the
server.

(8) If dirty data is written back to the server, but not fscache, we must
set zero_point above that.

(9) If a direct I/O write is made, set zero_point above that.

Assuming the above, any read from the server at or above the zero_point
position will return all zeroes.

The zero_point value can be stored in the cache, provided the above rules
are applied to it by any code that culls part of the local cache.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
diff 0d72b928 Mon Aug 07 13:38:33 MDT 2023 Jeff Layton <jlayton@kernel.org> fs: pass the request_mask to generic_fillattr

generic_fillattr just fills in the entire stat struct indiscriminately
today, copying data from the inode. There is at least one attribute
(STATX_CHANGE_COOKIE) that can have side effects when it is reported,
and we're looking at adding more with the addition of multigrain
timestamps.

Add a request_mask argument to generic_fillattr and have most callers
just pass in the value that is passed to getattr. Have other callers
(e.g. ksmbd) just pass in STATX_BASIC_STATS. Also move the setting of
STATX_CHANGE_COOKIE into generic_fillattr.

Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: "Paulo Alcantara (SUSE)" <pc@manguebit.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Message-Id: <20230807-mgctime-v7-2-d1dec143a704@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff cf7c33d3 Wed May 03 01:49:29 MDT 2023 Dominique Martinet <asmadeus@codewreck.org> 9p: remove dead stores (variable set again without being read)

The 9p code for some reason used to initialize variables outside of the
declaration, e.g. instead of just initializing the variable like this:

int retval = 0

We would be doing this:

int retval;
retval = 0;

This is perfectly fine and the compiler will just optimize dead stores
anyway, but scan-build seems to think this is a problem and there are
many of these warnings making the output of scan-build full of such
warnings:
fs/9p/vfs_inode.c:916:2: warning: Value stored to 'retval' is never read [deadcode.DeadStores]
retval = 0;
^ ~

I have no strong opinion here, but if we want to regularly run
scan-build we should fix these just to silence the messages.

I've confirmed these all are indeed ok to remove.

Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
diff d9bc0d11 Wed Dec 07 19:40:37 MST 2022 Eric Van Hensbergen <ericvh@kernel.org> fs/9p: Consolidate file operations and add readahead and writeback

We had 3 different sets of file operations across 2 different protocol
variants differentiated by cache which really only changed 3
functions. But the real problem is that certain file modes, mount
options, and other factors weren't being considered when we
decided whether or not to use caches.

This consolidates all the operations and switches
to conditionals within a common set to decide whether or not
to do different aspects of caching.

Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
Reviewed-by: Dominique Martinet <asmadeus@codewreck.org>
diff 874c8ca1 Thu Jun 09 14:46:04 MDT 2022 David Howells <dhowells@redhat.com> netfs: Fix gcc-12 warning by embedding vfs inode in netfs_i_context

While randstruct was satisfied with using an open-coded "void *" offset
cast for the netfs_i_context <-> inode casting, __builtin_object_size() as
used by FORTIFY_SOURCE was not as easily fooled. This was causing the
following complaint[1] from gcc v12:

In file included from include/linux/string.h:253,
from include/linux/ceph/ceph_debug.h:7,
from fs/ceph/inode.c:2:
In function 'fortify_memset_chk',
inlined from 'netfs_i_context_init' at include/linux/netfs.h:326:2,
inlined from 'ceph_alloc_inode' at fs/ceph/inode.c:463:2:
include/linux/fortify-string.h:242:25: warning: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning]
242 | __write_overflow_field(p_size_field, size);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fix this by embedding a struct inode into struct netfs_i_context (which
should perhaps be renamed to struct netfs_inode). The struct inode
vfs_inode fields are then removed from the 9p, afs, ceph and cifs inode
structs and vfs_inode is then simply changed to "netfs.inode" in those
filesystems.

Further, rename netfs_i_context to netfs_inode, get rid of the
netfs_inode() function that converted a netfs_i_context pointer to an
inode pointer (that can now be done with &ctx->inode) and rename the
netfs_i_context() function to netfs_inode() (which is now a wrapper
around container_of()).

Most of the changes were done with:

perl -p -i -e 's/vfs_inode/netfs.inode/'g \
`git grep -l 'vfs_inode' -- fs/{9p,afs,ceph,cifs}/*.[ch]`

Kees suggested doing it with a pair structure[2] and a special
declarator to insert that into the network filesystem's inode
wrapper[3], but I think it's cleaner to embed it - and then it doesn't
matter if struct randomisation reorders things.

Dave Chinner suggested using a filesystem-specific VFS_I() function in
each filesystem to convert that filesystem's own inode wrapper struct
into the VFS inode struct[4].

Version #2:
- Fix a couple of missed name changes due to a disabled cifs option.
- Rename nfs_i_context to nfs_inode
- Use "netfs" instead of "nic" as the member name in per-fs inode wrapper
structs.

[ This also undoes commit 507160f46c55 ("netfs: gcc-12: temporarily
disable '-Wattribute-warning' for now") that is no longer needed ]

Fixes: bc899ee1c898 ("netfs: Add a netfs inode context")
Reported-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
cc: Jonathan Corbet <corbet@lwn.net>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Steve French <smfrench@gmail.com>
cc: William Kucharski <william.kucharski@oracle.com>
cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
cc: Dave Chinner <david@fromorbit.com>
cc: linux-doc@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: samba-technical@lists.samba.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-hardening@vger.kernel.org
Link: https://lore.kernel.org/r/d2ad3a3d7bdd794c6efb562d2f2b655fb67756b9.camel@kernel.org/ [1]
Link: https://lore.kernel.org/r/20220517210230.864239-1-keescook@chromium.org/ [2]
Link: https://lore.kernel.org/r/20220518202212.2322058-1-keescook@chromium.org/ [3]
Link: https://lore.kernel.org/r/20220524101205.GI2306852@dread.disaster.area/ [4]
Link: https://lore.kernel.org/r/165296786831.3591209.12111293034669289733.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165305805651.4094995.7763502506786714216.stgit@warthog.procyon.org.uk # v2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff 874c8ca1 Thu Jun 09 14:46:04 MDT 2022 David Howells <dhowells@redhat.com> netfs: Fix gcc-12 warning by embedding vfs inode in netfs_i_context

While randstruct was satisfied with using an open-coded "void *" offset
cast for the netfs_i_context <-> inode casting, __builtin_object_size() as
used by FORTIFY_SOURCE was not as easily fooled. This was causing the
following complaint[1] from gcc v12:

In file included from include/linux/string.h:253,
from include/linux/ceph/ceph_debug.h:7,
from fs/ceph/inode.c:2:
In function 'fortify_memset_chk',
inlined from 'netfs_i_context_init' at include/linux/netfs.h:326:2,
inlined from 'ceph_alloc_inode' at fs/ceph/inode.c:463:2:
include/linux/fortify-string.h:242:25: warning: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning]
242 | __write_overflow_field(p_size_field, size);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fix this by embedding a struct inode into struct netfs_i_context (which
should perhaps be renamed to struct netfs_inode). The struct inode
vfs_inode fields are then removed from the 9p, afs, ceph and cifs inode
structs and vfs_inode is then simply changed to "netfs.inode" in those
filesystems.

Further, rename netfs_i_context to netfs_inode, get rid of the
netfs_inode() function that converted a netfs_i_context pointer to an
inode pointer (that can now be done with &ctx->inode) and rename the
netfs_i_context() function to netfs_inode() (which is now a wrapper
around container_of()).

Most of the changes were done with:

perl -p -i -e 's/vfs_inode/netfs.inode/'g \
`git grep -l 'vfs_inode' -- fs/{9p,afs,ceph,cifs}/*.[ch]`

Kees suggested doing it with a pair structure[2] and a special
declarator to insert that into the network filesystem's inode
wrapper[3], but I think it's cleaner to embed it - and then it doesn't
matter if struct randomisation reorders things.

Dave Chinner suggested using a filesystem-specific VFS_I() function in
each filesystem to convert that filesystem's own inode wrapper struct
into the VFS inode struct[4].

Version #2:
- Fix a couple of missed name changes due to a disabled cifs option.
- Rename nfs_i_context to nfs_inode
- Use "netfs" instead of "nic" as the member name in per-fs inode wrapper
structs.

[ This also undoes commit 507160f46c55 ("netfs: gcc-12: temporarily
disable '-Wattribute-warning' for now") that is no longer needed ]

Fixes: bc899ee1c898 ("netfs: Add a netfs inode context")
Reported-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
cc: Jonathan Corbet <corbet@lwn.net>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Steve French <smfrench@gmail.com>
cc: William Kucharski <william.kucharski@oracle.com>
cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
cc: Dave Chinner <david@fromorbit.com>
cc: linux-doc@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: samba-technical@lists.samba.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-hardening@vger.kernel.org
Link: https://lore.kernel.org/r/d2ad3a3d7bdd794c6efb562d2f2b655fb67756b9.camel@kernel.org/ [1]
Link: https://lore.kernel.org/r/20220517210230.864239-1-keescook@chromium.org/ [2]
Link: https://lore.kernel.org/r/20220518202212.2322058-1-keescook@chromium.org/ [3]
Link: https://lore.kernel.org/r/20220524101205.GI2306852@dread.disaster.area/ [4]
Link: https://lore.kernel.org/r/165296786831.3591209.12111293034669289733.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165305805651.4094995.7763502506786714216.stgit@warthog.procyon.org.uk # v2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff 874c8ca1 Thu Jun 09 14:46:04 MDT 2022 David Howells <dhowells@redhat.com> netfs: Fix gcc-12 warning by embedding vfs inode in netfs_i_context

While randstruct was satisfied with using an open-coded "void *" offset
cast for the netfs_i_context <-> inode casting, __builtin_object_size() as
used by FORTIFY_SOURCE was not as easily fooled. This was causing the
following complaint[1] from gcc v12:

In file included from include/linux/string.h:253,
from include/linux/ceph/ceph_debug.h:7,
from fs/ceph/inode.c:2:
In function 'fortify_memset_chk',
inlined from 'netfs_i_context_init' at include/linux/netfs.h:326:2,
inlined from 'ceph_alloc_inode' at fs/ceph/inode.c:463:2:
include/linux/fortify-string.h:242:25: warning: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning]
242 | __write_overflow_field(p_size_field, size);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fix this by embedding a struct inode into struct netfs_i_context (which
should perhaps be renamed to struct netfs_inode). The struct inode
vfs_inode fields are then removed from the 9p, afs, ceph and cifs inode
structs and vfs_inode is then simply changed to "netfs.inode" in those
filesystems.

Further, rename netfs_i_context to netfs_inode, get rid of the
netfs_inode() function that converted a netfs_i_context pointer to an
inode pointer (that can now be done with &ctx->inode) and rename the
netfs_i_context() function to netfs_inode() (which is now a wrapper
around container_of()).

Most of the changes were done with:

perl -p -i -e 's/vfs_inode/netfs.inode/'g \
`git grep -l 'vfs_inode' -- fs/{9p,afs,ceph,cifs}/*.[ch]`

Kees suggested doing it with a pair structure[2] and a special
declarator to insert that into the network filesystem's inode
wrapper[3], but I think it's cleaner to embed it - and then it doesn't
matter if struct randomisation reorders things.

Dave Chinner suggested using a filesystem-specific VFS_I() function in
each filesystem to convert that filesystem's own inode wrapper struct
into the VFS inode struct[4].

Version #2:
- Fix a couple of missed name changes due to a disabled cifs option.
- Rename nfs_i_context to nfs_inode
- Use "netfs" instead of "nic" as the member name in per-fs inode wrapper
structs.

[ This also undoes commit 507160f46c55 ("netfs: gcc-12: temporarily
disable '-Wattribute-warning' for now") that is no longer needed ]

Fixes: bc899ee1c898 ("netfs: Add a netfs inode context")
Reported-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
cc: Jonathan Corbet <corbet@lwn.net>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Steve French <smfrench@gmail.com>
cc: William Kucharski <william.kucharski@oracle.com>
cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
cc: Dave Chinner <david@fromorbit.com>
cc: linux-doc@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: samba-technical@lists.samba.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-hardening@vger.kernel.org
Link: https://lore.kernel.org/r/d2ad3a3d7bdd794c6efb562d2f2b655fb67756b9.camel@kernel.org/ [1]
Link: https://lore.kernel.org/r/20220517210230.864239-1-keescook@chromium.org/ [2]
Link: https://lore.kernel.org/r/20220518202212.2322058-1-keescook@chromium.org/ [3]
Link: https://lore.kernel.org/r/20220524101205.GI2306852@dread.disaster.area/ [4]
Link: https://lore.kernel.org/r/165296786831.3591209.12111293034669289733.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165305805651.4094995.7763502506786714216.stgit@warthog.procyon.org.uk # v2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff 874c8ca1 Thu Jun 09 14:46:04 MDT 2022 David Howells <dhowells@redhat.com> netfs: Fix gcc-12 warning by embedding vfs inode in netfs_i_context

While randstruct was satisfied with using an open-coded "void *" offset
cast for the netfs_i_context <-> inode casting, __builtin_object_size() as
used by FORTIFY_SOURCE was not as easily fooled. This was causing the
following complaint[1] from gcc v12:

In file included from include/linux/string.h:253,
from include/linux/ceph/ceph_debug.h:7,
from fs/ceph/inode.c:2:
In function 'fortify_memset_chk',
inlined from 'netfs_i_context_init' at include/linux/netfs.h:326:2,
inlined from 'ceph_alloc_inode' at fs/ceph/inode.c:463:2:
include/linux/fortify-string.h:242:25: warning: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning]
242 | __write_overflow_field(p_size_field, size);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fix this by embedding a struct inode into struct netfs_i_context (which
should perhaps be renamed to struct netfs_inode). The struct inode
vfs_inode fields are then removed from the 9p, afs, ceph and cifs inode
structs and vfs_inode is then simply changed to "netfs.inode" in those
filesystems.

Further, rename netfs_i_context to netfs_inode, get rid of the
netfs_inode() function that converted a netfs_i_context pointer to an
inode pointer (that can now be done with &ctx->inode) and rename the
netfs_i_context() function to netfs_inode() (which is now a wrapper
around container_of()).

Most of the changes were done with:

perl -p -i -e 's/vfs_inode/netfs.inode/'g \
`git grep -l 'vfs_inode' -- fs/{9p,afs,ceph,cifs}/*.[ch]`

Kees suggested doing it with a pair structure[2] and a special
declarator to insert that into the network filesystem's inode
wrapper[3], but I think it's cleaner to embed it - and then it doesn't
matter if struct randomisation reorders things.

Dave Chinner suggested using a filesystem-specific VFS_I() function in
each filesystem to convert that filesystem's own inode wrapper struct
into the VFS inode struct[4].

Version #2:
- Fix a couple of missed name changes due to a disabled cifs option.
- Rename nfs_i_context to nfs_inode
- Use "netfs" instead of "nic" as the member name in per-fs inode wrapper
structs.

[ This also undoes commit 507160f46c55 ("netfs: gcc-12: temporarily
disable '-Wattribute-warning' for now") that is no longer needed ]

Fixes: bc899ee1c898 ("netfs: Add a netfs inode context")
Reported-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
cc: Jonathan Corbet <corbet@lwn.net>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Steve French <smfrench@gmail.com>
cc: William Kucharski <william.kucharski@oracle.com>
cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
cc: Dave Chinner <david@fromorbit.com>
cc: linux-doc@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: samba-technical@lists.samba.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-hardening@vger.kernel.org
Link: https://lore.kernel.org/r/d2ad3a3d7bdd794c6efb562d2f2b655fb67756b9.camel@kernel.org/ [1]
Link: https://lore.kernel.org/r/20220517210230.864239-1-keescook@chromium.org/ [2]
Link: https://lore.kernel.org/r/20220518202212.2322058-1-keescook@chromium.org/ [3]
Link: https://lore.kernel.org/r/20220524101205.GI2306852@dread.disaster.area/ [4]
Link: https://lore.kernel.org/r/165296786831.3591209.12111293034669289733.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165305805651.4094995.7763502506786714216.stgit@warthog.procyon.org.uk # v2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff 874c8ca1 Thu Jun 09 14:46:04 MDT 2022 David Howells <dhowells@redhat.com> netfs: Fix gcc-12 warning by embedding vfs inode in netfs_i_context

While randstruct was satisfied with using an open-coded "void *" offset
cast for the netfs_i_context <-> inode casting, __builtin_object_size() as
used by FORTIFY_SOURCE was not as easily fooled. This was causing the
following complaint[1] from gcc v12:

In file included from include/linux/string.h:253,
from include/linux/ceph/ceph_debug.h:7,
from fs/ceph/inode.c:2:
In function 'fortify_memset_chk',
inlined from 'netfs_i_context_init' at include/linux/netfs.h:326:2,
inlined from 'ceph_alloc_inode' at fs/ceph/inode.c:463:2:
include/linux/fortify-string.h:242:25: warning: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning]
242 | __write_overflow_field(p_size_field, size);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fix this by embedding a struct inode into struct netfs_i_context (which
should perhaps be renamed to struct netfs_inode). The struct inode
vfs_inode fields are then removed from the 9p, afs, ceph and cifs inode
structs and vfs_inode is then simply changed to "netfs.inode" in those
filesystems.

Further, rename netfs_i_context to netfs_inode, get rid of the
netfs_inode() function that converted a netfs_i_context pointer to an
inode pointer (that can now be done with &ctx->inode) and rename the
netfs_i_context() function to netfs_inode() (which is now a wrapper
around container_of()).

Most of the changes were done with:

perl -p -i -e 's/vfs_inode/netfs.inode/'g \
`git grep -l 'vfs_inode' -- fs/{9p,afs,ceph,cifs}/*.[ch]`

Kees suggested doing it with a pair structure[2] and a special
declarator to insert that into the network filesystem's inode
wrapper[3], but I think it's cleaner to embed it - and then it doesn't
matter if struct randomisation reorders things.

Dave Chinner suggested using a filesystem-specific VFS_I() function in
each filesystem to convert that filesystem's own inode wrapper struct
into the VFS inode struct[4].

Version #2:
- Fix a couple of missed name changes due to a disabled cifs option.
- Rename nfs_i_context to nfs_inode
- Use "netfs" instead of "nic" as the member name in per-fs inode wrapper
structs.

[ This also undoes commit 507160f46c55 ("netfs: gcc-12: temporarily
disable '-Wattribute-warning' for now") that is no longer needed ]

Fixes: bc899ee1c898 ("netfs: Add a netfs inode context")
Reported-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
cc: Jonathan Corbet <corbet@lwn.net>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Steve French <smfrench@gmail.com>
cc: William Kucharski <william.kucharski@oracle.com>
cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
cc: Dave Chinner <david@fromorbit.com>
cc: linux-doc@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: samba-technical@lists.samba.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-hardening@vger.kernel.org
Link: https://lore.kernel.org/r/d2ad3a3d7bdd794c6efb562d2f2b655fb67756b9.camel@kernel.org/ [1]
Link: https://lore.kernel.org/r/20220517210230.864239-1-keescook@chromium.org/ [2]
Link: https://lore.kernel.org/r/20220518202212.2322058-1-keescook@chromium.org/ [3]
Link: https://lore.kernel.org/r/20220524101205.GI2306852@dread.disaster.area/ [4]
Link: https://lore.kernel.org/r/165296786831.3591209.12111293034669289733.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165305805651.4094995.7763502506786714216.stgit@warthog.procyon.org.uk # v2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff 874c8ca1 Thu Jun 09 14:46:04 MDT 2022 David Howells <dhowells@redhat.com> netfs: Fix gcc-12 warning by embedding vfs inode in netfs_i_context

While randstruct was satisfied with using an open-coded "void *" offset
cast for the netfs_i_context <-> inode casting, __builtin_object_size() as
used by FORTIFY_SOURCE was not as easily fooled. This was causing the
following complaint[1] from gcc v12:

In file included from include/linux/string.h:253,
from include/linux/ceph/ceph_debug.h:7,
from fs/ceph/inode.c:2:
In function 'fortify_memset_chk',
inlined from 'netfs_i_context_init' at include/linux/netfs.h:326:2,
inlined from 'ceph_alloc_inode' at fs/ceph/inode.c:463:2:
include/linux/fortify-string.h:242:25: warning: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning]
242 | __write_overflow_field(p_size_field, size);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fix this by embedding a struct inode into struct netfs_i_context (which
should perhaps be renamed to struct netfs_inode). The struct inode
vfs_inode fields are then removed from the 9p, afs, ceph and cifs inode
structs and vfs_inode is then simply changed to "netfs.inode" in those
filesystems.

Further, rename netfs_i_context to netfs_inode, get rid of the
netfs_inode() function that converted a netfs_i_context pointer to an
inode pointer (that can now be done with &ctx->inode) and rename the
netfs_i_context() function to netfs_inode() (which is now a wrapper
around container_of()).

Most of the changes were done with:

perl -p -i -e 's/vfs_inode/netfs.inode/'g \
`git grep -l 'vfs_inode' -- fs/{9p,afs,ceph,cifs}/*.[ch]`

Kees suggested doing it with a pair structure[2] and a special
declarator to insert that into the network filesystem's inode
wrapper[3], but I think it's cleaner to embed it - and then it doesn't
matter if struct randomisation reorders things.

Dave Chinner suggested using a filesystem-specific VFS_I() function in
each filesystem to convert that filesystem's own inode wrapper struct
into the VFS inode struct[4].

Version #2:
- Fix a couple of missed name changes due to a disabled cifs option.
- Rename nfs_i_context to nfs_inode
- Use "netfs" instead of "nic" as the member name in per-fs inode wrapper
structs.

[ This also undoes commit 507160f46c55 ("netfs: gcc-12: temporarily
disable '-Wattribute-warning' for now") that is no longer needed ]

Fixes: bc899ee1c898 ("netfs: Add a netfs inode context")
Reported-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
cc: Jonathan Corbet <corbet@lwn.net>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Steve French <smfrench@gmail.com>
cc: William Kucharski <william.kucharski@oracle.com>
cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
cc: Dave Chinner <david@fromorbit.com>
cc: linux-doc@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: samba-technical@lists.samba.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-hardening@vger.kernel.org
Link: https://lore.kernel.org/r/d2ad3a3d7bdd794c6efb562d2f2b655fb67756b9.camel@kernel.org/ [1]
Link: https://lore.kernel.org/r/20220517210230.864239-1-keescook@chromium.org/ [2]
Link: https://lore.kernel.org/r/20220518202212.2322058-1-keescook@chromium.org/ [3]
Link: https://lore.kernel.org/r/20220524101205.GI2306852@dread.disaster.area/ [4]
Link: https://lore.kernel.org/r/165296786831.3591209.12111293034669289733.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165305805651.4094995.7763502506786714216.stgit@warthog.procyon.org.uk # v2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
H A Dvfs_inode_dotl.cdiff 2dc92e59 Fri Jan 05 10:17:35 MST 2024 Eric Van Hensbergen <ericvh@kernel.org> fs/9p: Eliminate redundant non-cache path in mknod

Like symlink, mknod had a seperate path with different inode
allocation -- but this seems unnecessary, so eliminating this path.

Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
diff 0d72b928 Mon Aug 07 13:38:33 MDT 2023 Jeff Layton <jlayton@kernel.org> fs: pass the request_mask to generic_fillattr

generic_fillattr just fills in the entire stat struct indiscriminately
today, copying data from the inode. There is at least one attribute
(STATX_CHANGE_COOKIE) that can have side effects when it is reported,
and we're looking at adding more with the addition of multigrain
timestamps.

Add a request_mask argument to generic_fillattr and have most callers
just pass in the value that is passed to getattr. Have other callers
(e.g. ksmbd) just pass in STATX_BASIC_STATS. Also move the setting of
STATX_CHANGE_COOKIE into generic_fillattr.

Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: "Paulo Alcantara (SUSE)" <pc@manguebit.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Message-Id: <20230807-mgctime-v7-2-d1dec143a704@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff cf7c33d3 Wed May 03 01:49:29 MDT 2023 Dominique Martinet <asmadeus@codewreck.org> 9p: remove dead stores (variable set again without being read)

The 9p code for some reason used to initialize variables outside of the
declaration, e.g. instead of just initializing the variable like this:

int retval = 0

We would be doing this:

int retval;
retval = 0;

This is perfectly fine and the compiler will just optimize dead stores
anyway, but scan-build seems to think this is a problem and there are
many of these warnings making the output of scan-build full of such
warnings:
fs/9p/vfs_inode.c:916:2: warning: Value stored to 'retval' is never read [deadcode.DeadStores]
retval = 0;
^ ~

I have no strong opinion here, but if we want to regularly run
scan-build we should fix these just to silence the messages.

I've confirmed these all are indeed ok to remove.

Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
diff d9bc0d11 Wed Dec 07 19:40:37 MST 2022 Eric Van Hensbergen <ericvh@kernel.org> fs/9p: Consolidate file operations and add readahead and writeback

We had 3 different sets of file operations across 2 different protocol
variants differentiated by cache which really only changed 3
functions. But the real problem is that certain file modes, mount
options, and other factors weren't being considered when we
decided whether or not to use caches.

This consolidates all the operations and switches
to conditionals within a common set to decide whether or not
to do different aspects of caching.

Signed-off-by: Eric Van Hensbergen <ericvh@kernel.org>
Reviewed-by: Dominique Martinet <asmadeus@codewreck.org>
diff beca774f Sun Jun 12 01:00:05 MDT 2022 Dominique Martinet <asmadeus@codewreck.org> 9p: fix fid refcount leak in v9fs_vfs_atomic_open_dotl

We need to release directory fid if we fail halfway through open

This fixes fid leaking with xfstests generic 531

Link: https://lkml.kernel.org/r/20220612085330.1451496-2-asmadeus@codewreck.org
Fixes: 6636b6dcc3db ("9p: add refcount to p9_fid struct")
Cc: stable@vger.kernel.org
Reported-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
diff 24e42e32 Wed Nov 18 02:06:42 MST 2020 David Howells <dhowells@redhat.com> 9p: Use fscache indexing rewrite and reenable caching

Change the 9p filesystem to take account of the changes to fscache's
indexing rewrite and reenable caching in 9p.

The following changes have been made:

(1) The fscache_netfs struct is no more, and there's no need to register
the filesystem as a whole.

(2) The session cookie is now an fscache_volume cookie, allocated with
fscache_acquire_volume(). That takes three parameters: a string
representing the "volume" in the index, a string naming the cache to
use (or NULL) and a u64 that conveys coherency metadata for the
volume.

For 9p, I've made it render the volume name string as:

"9p,<devname>,<cachetag>"

where the cachetag is replaced by the aname if it wasn't supplied.

This probably needs rethinking a bit as the aname can have slashes in
it. It might be better to hash the cachetag and use the hash or I
could substitute commas for the slashes or something.

(3) The fscache_cookie_def is no more and needed information is passed
directly to fscache_acquire_cookie(). The cache no longer calls back
into the filesystem, but rather metadata changes are indicated at
other times.

fscache_acquire_cookie() is passed the same keying and coherency
information as before.

(4) The functions to set/reset/flush cookies are removed and
fscache_use_cookie() and fscache_unuse_cookie() are used instead.

fscache_use_cookie() is passed a flag to indicate if the cookie is
opened for writing. fscache_unuse_cookie() is passed updates for the
metadata if we changed it (ie. if the file was opened for writing).

These are called when the file is opened or closed.

(5) wait_on_page_bit[_killable]() is replaced with the specific wait
functions for the bits waited upon.

(6) I've got rid of some of the 9p-specific cache helper functions and
called things like fscache_relinquish_cookie() directly as they'll
optimise away if v9fs_inode_cookie() returns an unconditional NULL
(which will be the case if CONFIG_9P_FSCACHE=n).

(7) v9fs_vfs_setattr() is made to call fscache_resize() to change the size
of the cache object.

Notes:

(A) We should call fscache_invalidate() if we detect that the server's
copy of a file got changed by a third party, but I don't know where to
do that. We don't need to do that when allocating the cookie as we
get a check-and-invalidate when we initially bind to the cache object.

(B) The copy-to-cache-on-writeback side of things will be handled in
separate patch.

Changes
=======
ver #3:
- Canonicalise the cookie key and coherency data to make them
endianness-independent.

ver #2:
- Use gfpflags_allow_blocking() rather than using flag directly.
- fscache_acquire_volume() now returns errors.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Dominique Martinet <asmadeus@codewreck.org>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: v9fs-developer@lists.sourceforge.net
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819664645.215744.1555314582005286846.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906975017.143852.3459573173204394039.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967178512.1823006.17377493641569138183.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021573143.640689.3977487095697717967.stgit@warthog.procyon.org.uk/ # v4
diff 24e42e32 Wed Nov 18 02:06:42 MST 2020 David Howells <dhowells@redhat.com> 9p: Use fscache indexing rewrite and reenable caching

Change the 9p filesystem to take account of the changes to fscache's
indexing rewrite and reenable caching in 9p.

The following changes have been made:

(1) The fscache_netfs struct is no more, and there's no need to register
the filesystem as a whole.

(2) The session cookie is now an fscache_volume cookie, allocated with
fscache_acquire_volume(). That takes three parameters: a string
representing the "volume" in the index, a string naming the cache to
use (or NULL) and a u64 that conveys coherency metadata for the
volume.

For 9p, I've made it render the volume name string as:

"9p,<devname>,<cachetag>"

where the cachetag is replaced by the aname if it wasn't supplied.

This probably needs rethinking a bit as the aname can have slashes in
it. It might be better to hash the cachetag and use the hash or I
could substitute commas for the slashes or something.

(3) The fscache_cookie_def is no more and needed information is passed
directly to fscache_acquire_cookie(). The cache no longer calls back
into the filesystem, but rather metadata changes are indicated at
other times.

fscache_acquire_cookie() is passed the same keying and coherency
information as before.

(4) The functions to set/reset/flush cookies are removed and
fscache_use_cookie() and fscache_unuse_cookie() are used instead.

fscache_use_cookie() is passed a flag to indicate if the cookie is
opened for writing. fscache_unuse_cookie() is passed updates for the
metadata if we changed it (ie. if the file was opened for writing).

These are called when the file is opened or closed.

(5) wait_on_page_bit[_killable]() is replaced with the specific wait
functions for the bits waited upon.

(6) I've got rid of some of the 9p-specific cache helper functions and
called things like fscache_relinquish_cookie() directly as they'll
optimise away if v9fs_inode_cookie() returns an unconditional NULL
(which will be the case if CONFIG_9P_FSCACHE=n).

(7) v9fs_vfs_setattr() is made to call fscache_resize() to change the size
of the cache object.

Notes:

(A) We should call fscache_invalidate() if we detect that the server's
copy of a file got changed by a third party, but I don't know where to
do that. We don't need to do that when allocating the cookie as we
get a check-and-invalidate when we initially bind to the cache object.

(B) The copy-to-cache-on-writeback side of things will be handled in
separate patch.

Changes
=======
ver #3:
- Canonicalise the cookie key and coherency data to make them
endianness-independent.

ver #2:
- Use gfpflags_allow_blocking() rather than using flag directly.
- fscache_acquire_volume() now returns errors.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Dominique Martinet <asmadeus@codewreck.org>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: v9fs-developer@lists.sourceforge.net
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819664645.215744.1555314582005286846.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906975017.143852.3459573173204394039.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967178512.1823006.17377493641569138183.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021573143.640689.3977487095697717967.stgit@warthog.procyon.org.uk/ # v4
diff 024b7d6a Tue Nov 02 07:12:01 MDT 2021 Dominique Martinet <asmadeus@codewreck.org> 9p: fix file headers

- add missing SPDX-License-Identifier
- remove (sometimes incorrect) file name from file header

Link: http://lkml.kernel.org/r/20211102134608.1588018-2-dominique.martinet@atmark-techno.com
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
diff bc868036 Mon Oct 04 15:07:22 MDT 2021 David Howells <dhowells@redhat.com> 9p: Fix a bunch of kerneldoc warnings shown up by W=1

Fix a bunch of kerneldoc warnings shown up by W=1 in the 9p filesystem:

(1) Add/remove/fix kerneldoc parameters descriptions.

(2) Move __add_fid() from between v9fs_fid_add() and its comment.

(3) 9p's caches_show() doesn't really make sense as an API function, so
remove the kerneldoc annotation. It's also not prefixed with 'v9fs_'.
Also remove the kerneldoc markers from the 9p fscache wrappers.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Dominique Martinet <asmadeus@codewreck.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: Mauro Carvalho Chehab <mchehab@kernel.org>
cc: v9fs-developer@lists.sourceforge.net
cc: linux-fsdevel@vger.kernel.org
cc: linux-doc@vger.kernel.org
Link: https://lore.kernel.org/r/163214005516.2945267.7000234432243167892.stgit@warthog.procyon.org.uk/ # rfc v1
Link: https://lore.kernel.org/r/163281899704.2790286.9177774252843775348.stgit@warthog.procyon.org.uk/ # rfc v2
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
/linux-master/fs/adfs/
H A Dinode.cdiff 2c69e205 Fri Apr 29 08:40:40 MDT 2022 Matthew Wilcox (Oracle) <willy@infradead.org> fs: Convert block_read_full_page() to block_read_full_folio()

This function is NOT converted to handle large folios, so include
an assert that the filesystem isn't passing one in. Otherwise, use
the folio functions instead of the page functions, where they exist.
Convert all filesystems which use block_read_full_page().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff d2912cb1 Tue Jun 04 02:11:33 MDT 2019 Thomas Gleixner <tglx@linutronix.de> treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff d2912cb1 Tue Jun 04 02:11:33 MDT 2019 Thomas Gleixner <tglx@linutronix.de> treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff d2912cb1 Tue Jun 04 02:11:33 MDT 2019 Thomas Gleixner <tglx@linutronix.de> treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff 2b0143b5 Tue Mar 17 16:25:59 MDT 2015 David Howells <dhowells@redhat.com> VFS: normal filesystems (and lustre): d_inode() annotations

that's the bulk of filesystem drivers dealing with inodes of their own

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff 2c27c65e Fri Jun 04 03:30:04 MDT 2010 Christoph Hellwig <hch@lst.de> check ATTR_SIZE contraints in inode_change_ok

Make sure we check the truncate constraints early on in ->setattr by adding
those checks to inode_change_ok. Also clean up and document inode_change_ok
to make this obvious.

As a fallout we don't have to call inode_newsize_ok from simple_setsize and
simplify it down to a truncate_setsize which doesn't return an error. This
simplifies a lot of setattr implementations and means we use truncate_setsize
almost everywhere. Get rid of fat_setsize now that it's trivial and mark
ext2_setsize static to make the calling convention obvious.

Keep the inode_newsize_ok in vmtruncate for now as all callers need an
audit for its removal anyway.

Note: setattr code in ecryptfs doesn't call inode_change_ok at all and
needs a deeper audit, but that is left for later.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
/linux-master/fs/affs/
H A Dinode.cdiff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff b2441318 Wed Nov 01 08:07:57 MDT 2017 Greg Kroah-Hartman <gregkh@linuxfoundation.org> License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff b2441318 Wed Nov 01 08:07:57 MDT 2017 Greg Kroah-Hartman <gregkh@linuxfoundation.org> License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff 5b825c3a Thu Feb 02 09:54:15 MST 2017 Ingo Molnar <mingo@kernel.org> sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h>

Add #include <linux/cred.h> dependencies to all .c files rely on sched.h
doing that for them.

Note that even if the count where we need to add extra headers seems high,
it's still a net win, because <linux/sched.h> is included in over
2,200 files ...

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff 2b0143b5 Tue Mar 17 16:25:59 MDT 2015 David Howells <dhowells@redhat.com> VFS: normal filesystems (and lustre): d_inode() annotations

that's the bulk of filesystem drivers dealing with inodes of their own

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff 5a0e3ad6 Wed Mar 24 02:04:11 MDT 2010 Tejun Heo <tj@kernel.org> include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.

2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).

* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
diff 5a0e3ad6 Wed Mar 24 02:04:11 MDT 2010 Tejun Heo <tj@kernel.org> include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.

2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).

* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
diff 2be3c790 Tue Feb 20 14:58:11 MST 2007 Christoph Hellwig <hch@lst.de> [PATCH] affs: implement ->drop_inode

affs wants to truncate the inode when the last user goes away, currently it
does that through a potentially racy i_count check in ->put_inode. But we
already have a method that's called just after the we dropped the last
reference, ->drop_inode. This patch implements affs_drop_inode to take
advantage of this.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
/linux-master/fs/
H A Dattr.cdiff 16a94965 Wed Oct 04 12:52:38 MDT 2023 Jeff Layton <jlayton@kernel.org> fs: convert core infrastructure to new timestamp accessors

Convert the core vfs code to use the new timestamp accessor functions.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20231004185239.80830-2-jlayton@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff 5d1f903f Wed Jul 12 12:58:49 MDT 2023 Christian Brauner <brauner@kernel.org> attr: block mode changes of symlinks

Changing the mode of symlinks is meaningless as the vfs doesn't take the
mode of a symlink into account during path lookup permission checking.

However, the vfs doesn't block mode changes on symlinks. This however,
has lead to an untenable mess roughly classifiable into the following
two categories:

(1) Filesystems that don't implement a i_op->setattr() for symlinks.

Such filesystems may or may not know that without i_op->setattr()
defined, notify_change() falls back to simple_setattr() causing the
inode's mode in the inode cache to be changed.

That's a generic issue as this will affect all non-size changing
inode attributes including ownership changes.

Example: afs

(2) Filesystems that fail with EOPNOTSUPP but change the mode of the
symlink nonetheless.

Some filesystems will happily update the mode of a symlink but still
return EOPNOTSUPP. This is the biggest source of confusion for
userspace.

The EOPNOTSUPP in this case comes from POSIX ACLs. Specifically it
comes from filesystems that call posix_acl_chmod(), e.g., btrfs via

if (!err && attr->ia_valid & ATTR_MODE)
err = posix_acl_chmod(idmap, dentry, inode->i_mode);

Filesystems including btrfs don't implement i_op->set_acl() so
posix_acl_chmod() will report EOPNOTSUPP.

When posix_acl_chmod() is called, most filesystems will have
finished updating the inode.

Perversely, this has the consequences that this behavior may depend
on two kconfig options and mount options:

* CONFIG_POSIX_ACL={y,n}
* CONFIG_${FSTYPE}_POSIX_ACL={y,n}
* Opt_acl, Opt_noacl

Example: btrfs, ext4, xfs

The only way to change the mode on a symlink currently involves abusing
an O_PATH file descriptor in the following manner:

fd = openat(-1, "/path/to/link", O_CLOEXEC | O_PATH | O_NOFOLLOW);

char path[PATH_MAX];
snprintf(path, sizeof(path), "/proc/self/fd/%d", fd);
chmod(path, 0000);

But for most major filesystems with POSIX ACL support such as btrfs,
ext4, ceph, tmpfs, xfs and others this will fail with EOPNOTSUPP with
the mode still updated due to the aforementioned posix_acl_chmod()
nonsense.

So, given that for all major filesystems this would fail with EOPNOTSUPP
and that both glibc (cf. [1]) and musl (cf. [2]) outright block mode
changes on symlinks we should just try and block mode changes on
symlinks directly in the vfs and have a clean break with this nonsense.

If this causes any regressions, we do the next best thing and fix up all
filesystems that do return EOPNOTSUPP with the mode updated to not call
posix_acl_chmod() on symlinks.

But as usual, let's try the clean cut solution first. It's a simple
patch that can be easily reverted. Not marking this for backport as I'll
do that manually if we're reasonably sure that this works and there are
no strong objections.

We could block this in chmod_common() but it's more appropriate to do it
notify_change() as it will also mean that we catch filesystems that
change symlink permissions explicitly or accidently.

Similar proposals were floated in the past as in [3] and [4] and again
recently in [5]. There's also a couple of bugs about this inconsistency
as in [6] and [7].

Link: https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/fchmodat.c;h=99527a3727e44cb8661ee1f743068f108ec93979;hb=HEAD [1]
Link: https://git.musl-libc.org/cgit/musl/tree/src/stat/fchmodat.c [2]
Link: https://lore.kernel.org/all/20200911065733.GA31579@infradead.org [3]
Link: https://sourceware.org/legacy-ml/libc-alpha/2020-02/msg00518.html [4]
Link: https://lore.kernel.org/lkml/87lefmbppo.fsf@oldenburg.str.redhat.com [5]
Link: https://sourceware.org/legacy-ml/libc-alpha/2020-02/msg00467.html [6]
Link: https://sourceware.org/bugzilla/show_bug.cgi?id=14578#c17 [7]
Reviewed-by: Aleksa Sarai <cyphar@cyphar.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org # please backport to all LTSes but not before v6.6-rc2 is tagged
Suggested-by: Christoph Hellwig <hch@lst.de>
Suggested-by: Florian Weimer <fweimer@redhat.com>
Message-Id: <20230712-vfs-chmod-symlinks-v2-1-08cfb92b61dd@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff 5d1f903f Wed Jul 12 12:58:49 MDT 2023 Christian Brauner <brauner@kernel.org> attr: block mode changes of symlinks

Changing the mode of symlinks is meaningless as the vfs doesn't take the
mode of a symlink into account during path lookup permission checking.

However, the vfs doesn't block mode changes on symlinks. This however,
has lead to an untenable mess roughly classifiable into the following
two categories:

(1) Filesystems that don't implement a i_op->setattr() for symlinks.

Such filesystems may or may not know that without i_op->setattr()
defined, notify_change() falls back to simple_setattr() causing the
inode's mode in the inode cache to be changed.

That's a generic issue as this will affect all non-size changing
inode attributes including ownership changes.

Example: afs

(2) Filesystems that fail with EOPNOTSUPP but change the mode of the
symlink nonetheless.

Some filesystems will happily update the mode of a symlink but still
return EOPNOTSUPP. This is the biggest source of confusion for
userspace.

The EOPNOTSUPP in this case comes from POSIX ACLs. Specifically it
comes from filesystems that call posix_acl_chmod(), e.g., btrfs via

if (!err && attr->ia_valid & ATTR_MODE)
err = posix_acl_chmod(idmap, dentry, inode->i_mode);

Filesystems including btrfs don't implement i_op->set_acl() so
posix_acl_chmod() will report EOPNOTSUPP.

When posix_acl_chmod() is called, most filesystems will have
finished updating the inode.

Perversely, this has the consequences that this behavior may depend
on two kconfig options and mount options:

* CONFIG_POSIX_ACL={y,n}
* CONFIG_${FSTYPE}_POSIX_ACL={y,n}
* Opt_acl, Opt_noacl

Example: btrfs, ext4, xfs

The only way to change the mode on a symlink currently involves abusing
an O_PATH file descriptor in the following manner:

fd = openat(-1, "/path/to/link", O_CLOEXEC | O_PATH | O_NOFOLLOW);

char path[PATH_MAX];
snprintf(path, sizeof(path), "/proc/self/fd/%d", fd);
chmod(path, 0000);

But for most major filesystems with POSIX ACL support such as btrfs,
ext4, ceph, tmpfs, xfs and others this will fail with EOPNOTSUPP with
the mode still updated due to the aforementioned posix_acl_chmod()
nonsense.

So, given that for all major filesystems this would fail with EOPNOTSUPP
and that both glibc (cf. [1]) and musl (cf. [2]) outright block mode
changes on symlinks we should just try and block mode changes on
symlinks directly in the vfs and have a clean break with this nonsense.

If this causes any regressions, we do the next best thing and fix up all
filesystems that do return EOPNOTSUPP with the mode updated to not call
posix_acl_chmod() on symlinks.

But as usual, let's try the clean cut solution first. It's a simple
patch that can be easily reverted. Not marking this for backport as I'll
do that manually if we're reasonably sure that this works and there are
no strong objections.

We could block this in chmod_common() but it's more appropriate to do it
notify_change() as it will also mean that we catch filesystems that
change symlink permissions explicitly or accidently.

Similar proposals were floated in the past as in [3] and [4] and again
recently in [5]. There's also a couple of bugs about this inconsistency
as in [6] and [7].

Link: https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/fchmodat.c;h=99527a3727e44cb8661ee1f743068f108ec93979;hb=HEAD [1]
Link: https://git.musl-libc.org/cgit/musl/tree/src/stat/fchmodat.c [2]
Link: https://lore.kernel.org/all/20200911065733.GA31579@infradead.org [3]
Link: https://sourceware.org/legacy-ml/libc-alpha/2020-02/msg00518.html [4]
Link: https://lore.kernel.org/lkml/87lefmbppo.fsf@oldenburg.str.redhat.com [5]
Link: https://sourceware.org/legacy-ml/libc-alpha/2020-02/msg00467.html [6]
Link: https://sourceware.org/bugzilla/show_bug.cgi?id=14578#c17 [7]
Reviewed-by: Aleksa Sarai <cyphar@cyphar.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org # please backport to all LTSes but not before v6.6-rc2 is tagged
Suggested-by: Christoph Hellwig <hch@lst.de>
Suggested-by: Florian Weimer <fweimer@redhat.com>
Message-Id: <20230712-vfs-chmod-symlinks-v2-1-08cfb92b61dd@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff 5d1f903f Wed Jul 12 12:58:49 MDT 2023 Christian Brauner <brauner@kernel.org> attr: block mode changes of symlinks

Changing the mode of symlinks is meaningless as the vfs doesn't take the
mode of a symlink into account during path lookup permission checking.

However, the vfs doesn't block mode changes on symlinks. This however,
has lead to an untenable mess roughly classifiable into the following
two categories:

(1) Filesystems that don't implement a i_op->setattr() for symlinks.

Such filesystems may or may not know that without i_op->setattr()
defined, notify_change() falls back to simple_setattr() causing the
inode's mode in the inode cache to be changed.

That's a generic issue as this will affect all non-size changing
inode attributes including ownership changes.

Example: afs

(2) Filesystems that fail with EOPNOTSUPP but change the mode of the
symlink nonetheless.

Some filesystems will happily update the mode of a symlink but still
return EOPNOTSUPP. This is the biggest source of confusion for
userspace.

The EOPNOTSUPP in this case comes from POSIX ACLs. Specifically it
comes from filesystems that call posix_acl_chmod(), e.g., btrfs via

if (!err && attr->ia_valid & ATTR_MODE)
err = posix_acl_chmod(idmap, dentry, inode->i_mode);

Filesystems including btrfs don't implement i_op->set_acl() so
posix_acl_chmod() will report EOPNOTSUPP.

When posix_acl_chmod() is called, most filesystems will have
finished updating the inode.

Perversely, this has the consequences that this behavior may depend
on two kconfig options and mount options:

* CONFIG_POSIX_ACL={y,n}
* CONFIG_${FSTYPE}_POSIX_ACL={y,n}
* Opt_acl, Opt_noacl

Example: btrfs, ext4, xfs

The only way to change the mode on a symlink currently involves abusing
an O_PATH file descriptor in the following manner:

fd = openat(-1, "/path/to/link", O_CLOEXEC | O_PATH | O_NOFOLLOW);

char path[PATH_MAX];
snprintf(path, sizeof(path), "/proc/self/fd/%d", fd);
chmod(path, 0000);

But for most major filesystems with POSIX ACL support such as btrfs,
ext4, ceph, tmpfs, xfs and others this will fail with EOPNOTSUPP with
the mode still updated due to the aforementioned posix_acl_chmod()
nonsense.

So, given that for all major filesystems this would fail with EOPNOTSUPP
and that both glibc (cf. [1]) and musl (cf. [2]) outright block mode
changes on symlinks we should just try and block mode changes on
symlinks directly in the vfs and have a clean break with this nonsense.

If this causes any regressions, we do the next best thing and fix up all
filesystems that do return EOPNOTSUPP with the mode updated to not call
posix_acl_chmod() on symlinks.

But as usual, let's try the clean cut solution first. It's a simple
patch that can be easily reverted. Not marking this for backport as I'll
do that manually if we're reasonably sure that this works and there are
no strong objections.

We could block this in chmod_common() but it's more appropriate to do it
notify_change() as it will also mean that we catch filesystems that
change symlink permissions explicitly or accidently.

Similar proposals were floated in the past as in [3] and [4] and again
recently in [5]. There's also a couple of bugs about this inconsistency
as in [6] and [7].

Link: https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/fchmodat.c;h=99527a3727e44cb8661ee1f743068f108ec93979;hb=HEAD [1]
Link: https://git.musl-libc.org/cgit/musl/tree/src/stat/fchmodat.c [2]
Link: https://lore.kernel.org/all/20200911065733.GA31579@infradead.org [3]
Link: https://sourceware.org/legacy-ml/libc-alpha/2020-02/msg00518.html [4]
Link: https://lore.kernel.org/lkml/87lefmbppo.fsf@oldenburg.str.redhat.com [5]
Link: https://sourceware.org/legacy-ml/libc-alpha/2020-02/msg00467.html [6]
Link: https://sourceware.org/bugzilla/show_bug.cgi?id=14578#c17 [7]
Reviewed-by: Aleksa Sarai <cyphar@cyphar.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org # please backport to all LTSes but not before v6.6-rc2 is tagged
Suggested-by: Christoph Hellwig <hch@lst.de>
Suggested-by: Florian Weimer <fweimer@redhat.com>
Message-Id: <20230712-vfs-chmod-symlinks-v2-1-08cfb92b61dd@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff 4f704d9a Mon Mar 13 17:51:10 MDT 2023 Christian Brauner <brauner@kernel.org> nfs: use vfs setgid helper

We've aligned setgid behavior over multiple kernel releases. The details
can be found in the following two merge messages:
cf619f891971 ("Merge tag 'fs.ovl.setgid.v6.2')
426b4ca2d6a5 ("Merge tag 'fs.setgid.v6.0')
Consistent setgid stripping behavior is now encapsulated in the
setattr_should_drop_sgid() helper which is used by all filesystems that
strip setgid bits outside of vfs proper. Switch nfs to rely on this
helper as well. Without this patch the setgid stripping tests in
xfstests will fail.

Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Message-Id: <20230313-fs-nfs-setgid-v2-1-9a59f436cfc0@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff e2ebff9c Mon Aug 08 02:52:35 MDT 2022 David Howells <dhowells@redhat.com> vfs: Check the truncate maximum size in inode_newsize_ok()

If something manages to set the maximum file size to MAX_OFFSET+1, this
can cause the xfs and ext4 filesystems at least to become corrupt.

Ordinarily, the kernel protects against userspace trying this by
checking the value early in the truncate() and ftruncate() system calls
calls - but there are at least two places that this check is bypassed:

(1) Cachefiles will round up the EOF of the backing file to DIO block
size so as to allow DIO on the final block - but this might push
the offset negative. It then calls notify_change(), but this
inadvertently bypasses the checking. This can be triggered if
someone puts an 8EiB-1 file on a server for someone else to try and
access by, say, nfs.

(2) ksmbd doesn't check the value it is given in set_end_of_file_info()
and then calls vfs_truncate() directly - which also bypasses the
check.

In both cases, it is potentially possible for a network filesystem to
cause a disk filesystem to be corrupted: cachefiles in the client's
cache filesystem; ksmbd in the server's filesystem.

nfsd is okay as it checks the value, but we can then remove this check
too.

Fix this by adding a check to inode_newsize_ok(), as called from
setattr_prepare(), thereby catching the issue as filesystems set up to
perform the truncate with minimal opportunity for bypassing the new
check.

Fixes: 1f08c925e7a3 ("cachefiles: Implement backing file wrangling")
Fixes: f44158485826 ("cifsd: add file operations")
Signed-off-by: David Howells <dhowells@redhat.com>
Reported-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Cc: stable@kernel.org
Acked-by: Alexander Viro <viro@zeniv.linux.org.uk>
cc: Steve French <sfrench@samba.org>
cc: Hyunchul Lee <hyc.lee@gmail.com>
cc: Chuck Lever <chuck.lever@oracle.com>
cc: Dave Wysochanski <dwysocha@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff 168f9128 Mon Jun 13 05:15:17 MDT 2022 Christian Brauner <brauner@kernel.org> fs: account for group membership

When calling setattr_prepare() to determine the validity of the
attributes the ia_{g,u}id fields contain the value that will be written
to inode->i_{g,u}id. This is exactly the same for idmapped and
non-idmapped mounts and allows callers to pass in the values they want
to see written to inode->i_{g,u}id.

When group ownership is changed a caller whose fsuid owns the inode can
change the group of the inode to any group they are a member of. When
searching through the caller's groups we need to use the gid mapped
according to the idmapped mount otherwise we will fail to change
ownership for unprivileged users.

Consider a caller running with fsuid and fsgid 1000 using an idmapped
mount that maps id 65534 to 1000 and 65535 to 1001. Consequently, a file
owned by 65534:65535 in the filesystem will be owned by 1000:1001 in the
idmapped mount.

The caller now requests the gid of the file to be changed to 1000 going
through the idmapped mount. In the vfs we will immediately map the
requested gid to the value that will need to be written to inode->i_gid
and place it in attr->ia_gid. Since this idmapped mount maps 65534 to
1000 we place 65534 in attr->ia_gid.

When we check whether the caller is allowed to change group ownership we
first validate that their fsuid matches the inode's uid. The
inode->i_uid is 65534 which is mapped to uid 1000 in the idmapped mount.
Since the caller's fsuid is 1000 we pass the check.

We now check whether the caller is allowed to change inode->i_gid to the
requested gid by calling in_group_p(). This will compare the passed in
gid to the caller's fsgid and search the caller's additional groups.

Since we're dealing with an idmapped mount we need to pass in the gid
mapped according to the idmapped mount. This is akin to checking whether
a caller is privileged over the future group the inode is owned by. And
that needs to take the idmapped mount into account. Note, all helpers
are nops without idmapped mounts.

New regression test sent to xfstests.

Link: https://github.com/lxc/lxd/issues/10537
Link: https://lore.kernel.org/r/20220613111517.2186646-1-brauner@kernel.org
Fixes: 2f221d6f7b88 ("attr: handle idmapped mounts")
Cc: Seth Forshee <sforshee@digitalocean.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@vger.kernel.org # 5.15+
CC: linux-fsdevel@vger.kernel.org
Reviewed-by: Seth Forshee <sforshee@digitalocean.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
diff 96821970 Tue Nov 09 07:57:12 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> fs: handle circular mappings correctly

When calling setattr_prepare() to determine the validity of the attributes the
ia_{g,u}id fields contain the value that will be written to inode->i_{g,u}id.
When the {g,u}id attribute of the file isn't altered and the caller's fs{g,u}id
matches the current {g,u}id attribute the attribute change is allowed.

The value in ia_{g,u}id does already account for idmapped mounts and will have
taken the relevant idmapping into account. So in order to verify that the
{g,u}id attribute isn't changed we simple need to compare the ia_{g,u}id value
against the inode's i_{g,u}id value.

This only has any meaning for idmapped mounts as idmapping helpers are
idempotent without them. And for idmapped mounts this really only has a meaning
when circular idmappings are used, i.e. mappings where e.g. id 1000 is mapped
to id 1001 and id 1001 is mapped to id 1000. Such ciruclar mappings can e.g. be
useful when sharing the same home directory between multiple users at the same
time.

As an example consider a directory with two files: /source/file1 owned by
{g,u}id 1000 and /source/file2 owned by {g,u}id 1001. Assume we create an
idmapped mount at /target with an idmapping that maps files owned by {g,u}id
1000 to being owned by {g,u}id 1001 and files owned by {g,u}id 1001 to being
owned by {g,u}id 1000. In effect, the idmapped mount at /target switches the
ownership of /source/file1 and source/file2, i.e. /target/file1 will be owned
by {g,u}id 1001 and /target/file2 will be owned by {g,u}id 1000.

This means that a user with fs{g,u}id 1000 must be allowed to setattr
/target/file2 from {g,u}id 1000 to {g,u}id 1000. Similar, a user with fs{g,u}id
1001 must be allowed to setattr /target/file1 from {g,u}id 1001 to {g,u}id
1001. Conversely, a user with fs{g,u}id 1000 must fail to setattr /target/file1
from {g,u}id 1001 to {g,u}id 1000. And a user with fs{g,u}id 1001 must fail to
setattr /target/file2 from {g,u}id 1000 to {g,u}id 1000. Both cases must fail
with EPERM for non-capable callers.

Before this patch we could end up denying legitimate attribute changes and
allowing invalid attribute changes when circular mappings are used. To even get
into this situation the caller must've been privileged both to create that
mapping and to create that idmapped mount.

This hasn't been seen in the wild anywhere but came up when expanding the
testsuite during work on a series of hardening patches. All idmapped fstests
pass without any regressions and we add new tests to verify the behavior of
circular mappings.

Link: https://lore.kernel.org/r/20211109145713.1868404-1-brauner@kernel.org
Fixes: 2f221d6f7b88 ("attr: handle idmapped mounts")
Cc: Seth Forshee <seth.forshee@digitalocean.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@vger.kernel.org
CC: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Seth Forshee <sforshee@digitalocean.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
H A Dinode.cdiff 8b3d8381 Tue Jan 16 00:53:35 MST 2024 Baolin Wang <baolin.wang@linux.alibaba.com> fs: improve dump_mapping() robustness

We met a kernel crash issue when running stress-ng testing, and the
system crashes when printing the dentry name in dump_mapping().

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
pc : dentry_name+0xd8/0x224
lr : pointer+0x22c/0x370
sp : ffff800025f134c0
......
Call trace:
dentry_name+0xd8/0x224
pointer+0x22c/0x370
vsnprintf+0x1ec/0x730
vscnprintf+0x2c/0x60
vprintk_store+0x70/0x234
vprintk_emit+0xe0/0x24c
vprintk_default+0x3c/0x44
vprintk_func+0x84/0x2d0
printk+0x64/0x88
__dump_page+0x52c/0x530
dump_page+0x14/0x20
set_migratetype_isolate+0x110/0x224
start_isolate_page_range+0xc4/0x20c
offline_pages+0x124/0x474
memory_block_offline+0x44/0xf4
memory_subsys_offline+0x3c/0x70
device_offline+0xf0/0x120
......

The root cause is that, one thread is doing page migration, and we will
use the target page's ->mapping field to save 'anon_vma' pointer between
page unmap and page move, and now the target page is locked and refcount
is 1.

Currently, there is another stress-ng thread performing memory hotplug,
attempting to offline the target page that is being migrated. It discovers
that the refcount of this target page is 1, preventing the offline operation,
thus proceeding to dump the page. However, page_mapping() of the target
page may return an incorrect file mapping to crash the system in dump_mapping(),
since the target page->mapping only saves 'anon_vma' pointer without setting
PAGE_MAPPING_ANON flag.

The page migration issue has been fixed by commit d1adb25df711 ("mm: migrate:
fix getting incorrect page mapping during page migration"). In addition,
Matthew suggested we should also improve dump_mapping()'s robustness to
resilient against the kernel crash [1].

With checking the 'dentry.parent' and 'dentry.d_name.name' used by
dentry_name(), I can see dump_mapping() will output the invalid dentry
instead of crashing the system when this issue is reproduced again.

[12211.189128] page:fffff7de047741c0 refcount:1 mapcount:0 mapping:ffff989117f55ea0 index:0x1 pfn:0x211dd07
[12211.189144] aops:0x0 ino:1 invalid dentry:74786574206e6870
[12211.189148] flags: 0x57ffffc0000001(locked|node=1|zone=2|lastcpupid=0x1fffff)
[12211.189150] page_type: 0xffffffff()
[12211.189153] raw: 0057ffffc0000001 0000000000000000 dead000000000122 ffff989117f55ea0
[12211.189154] raw: 0000000000000001 0000000000000001 00000001ffffffff 0000000000000000
[12211.189155] page dumped because: unmovable page

[1] https://lore.kernel.org/all/ZXxn%2F0oixJxxAnpF@casper.infradead.org/

Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Link: https://lore.kernel.org/r/937ab1f87328516821d39be672b6bc18861d9d3e.1705391420.git.baolin.wang@linux.alibaba.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff 8b3d8381 Tue Jan 16 00:53:35 MST 2024 Baolin Wang <baolin.wang@linux.alibaba.com> fs: improve dump_mapping() robustness

We met a kernel crash issue when running stress-ng testing, and the
system crashes when printing the dentry name in dump_mapping().

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
pc : dentry_name+0xd8/0x224
lr : pointer+0x22c/0x370
sp : ffff800025f134c0
......
Call trace:
dentry_name+0xd8/0x224
pointer+0x22c/0x370
vsnprintf+0x1ec/0x730
vscnprintf+0x2c/0x60
vprintk_store+0x70/0x234
vprintk_emit+0xe0/0x24c
vprintk_default+0x3c/0x44
vprintk_func+0x84/0x2d0
printk+0x64/0x88
__dump_page+0x52c/0x530
dump_page+0x14/0x20
set_migratetype_isolate+0x110/0x224
start_isolate_page_range+0xc4/0x20c
offline_pages+0x124/0x474
memory_block_offline+0x44/0xf4
memory_subsys_offline+0x3c/0x70
device_offline+0xf0/0x120
......

The root cause is that, one thread is doing page migration, and we will
use the target page's ->mapping field to save 'anon_vma' pointer between
page unmap and page move, and now the target page is locked and refcount
is 1.

Currently, there is another stress-ng thread performing memory hotplug,
attempting to offline the target page that is being migrated. It discovers
that the refcount of this target page is 1, preventing the offline operation,
thus proceeding to dump the page. However, page_mapping() of the target
page may return an incorrect file mapping to crash the system in dump_mapping(),
since the target page->mapping only saves 'anon_vma' pointer without setting
PAGE_MAPPING_ANON flag.

The page migration issue has been fixed by commit d1adb25df711 ("mm: migrate:
fix getting incorrect page mapping during page migration"). In addition,
Matthew suggested we should also improve dump_mapping()'s robustness to
resilient against the kernel crash [1].

With checking the 'dentry.parent' and 'dentry.d_name.name' used by
dentry_name(), I can see dump_mapping() will output the invalid dentry
instead of crashing the system when this issue is reproduced again.

[12211.189128] page:fffff7de047741c0 refcount:1 mapcount:0 mapping:ffff989117f55ea0 index:0x1 pfn:0x211dd07
[12211.189144] aops:0x0 ino:1 invalid dentry:74786574206e6870
[12211.189148] flags: 0x57ffffc0000001(locked|node=1|zone=2|lastcpupid=0x1fffff)
[12211.189150] page_type: 0xffffffff()
[12211.189153] raw: 0057ffffc0000001 0000000000000000 dead000000000122 ffff989117f55ea0
[12211.189154] raw: 0000000000000001 0000000000000001 00000001ffffffff 0000000000000000
[12211.189155] page dumped because: unmovable page

[1] https://lore.kernel.org/all/ZXxn%2F0oixJxxAnpF@casper.infradead.org/

Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Link: https://lore.kernel.org/r/937ab1f87328516821d39be672b6bc18861d9d3e.1705391420.git.baolin.wang@linux.alibaba.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff 9d5b9475 Mon Nov 20 16:35:12 MST 2023 Joel Granados <j.granados@samsung.com> fs: Remove the now superfluous sentinel elements from ctl_table array

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which
will reduce the overall build time size of the kernel and run time
memory bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)

Remove sentinel elements ctl_table struct. Special attention was placed in
making sure that an empty directory for fs/verity was created when
CONFIG_FS_VERITY_BUILTIN_SIGNATURES is not defined. In this case we use the
register sysctl call that expects a size.

Signed-off-by: Joel Granados <j.granados@samsung.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
diff 0a97c01c Thu Nov 30 12:40:18 MST 2023 Nhat Pham <nphamcs@gmail.com> list_lru: allow explicit memcg and NUMA node selection

Patch series "workload-specific and memory pressure-driven zswap
writeback", v8.

There are currently several issues with zswap writeback:

1. There is only a single global LRU for zswap, making it impossible to
perform worload-specific shrinking - an memcg under memory pressure
cannot determine which pages in the pool it owns, and often ends up
writing pages from other memcgs. This issue has been previously
observed in practice and mitigated by simply disabling
memcg-initiated shrinking:

https://lore.kernel.org/all/20230530232435.3097106-1-nphamcs@gmail.com/T/#u

But this solution leaves a lot to be desired, as we still do not
have an avenue for an memcg to free up its own memory locked up in
the zswap pool.

2. We only shrink the zswap pool when the user-defined limit is hit.
This means that if we set the limit too high, cold data that are
unlikely to be used again will reside in the pool, wasting precious
memory. It is hard to predict how much zswap space will be needed
ahead of time, as this depends on the workload (specifically, on
factors such as memory access patterns and compressibility of the
memory pages).

This patch series solves these issues by separating the global zswap LRU
into per-memcg and per-NUMA LRUs, and performs workload-specific (i.e
memcg- and NUMA-aware) zswap writeback under memory pressure. The new
shrinker does not have any parameter that must be tuned by the user, and
can be opted in or out on a per-memcg basis.

As a proof of concept, we ran the following synthetic benchmark: build the
linux kernel in a memory-limited cgroup, and allocate some cold data in
tmpfs to see if the shrinker could write them out and improved the overall
performance. Depending on the amount of cold data generated, we observe
from 14% to 35% reduction in kernel CPU time used in the kernel builds.


This patch (of 6):

The interface of list_lru is based on the assumption that the list node
and the data it represents belong to the same allocated on the correct
node/memcg. While this assumption is valid for existing slab objects LRU
such as dentries and inodes, it is undocumented, and rather inflexible for
certain potential list_lru users (such as the upcoming zswap shrinker and
the THP shrinker). It has caused us a lot of issues during our
development.

This patch changes list_lru interface so that the caller must explicitly
specify numa node and memcg when adding and removing objects. The old
list_lru_add() and list_lru_del() are renamed to list_lru_add_obj() and
list_lru_del_obj(), respectively.

It also extends the list_lru API with a new function, list_lru_putback,
which undoes a previous list_lru_isolate call. Unlike list_lru_add, it
does not increment the LRU node count (as list_lru_isolate does not
decrement the node count). list_lru_putback also allows for explicit
memcg and NUMA node selection.

Link: https://lkml.kernel.org/r/20231130194023.4102148-1-nphamcs@gmail.com
Link: https://lkml.kernel.org/r/20231130194023.4102148-2-nphamcs@gmail.com
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Tested-by: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff 0a97c01c Thu Nov 30 12:40:18 MST 2023 Nhat Pham <nphamcs@gmail.com> list_lru: allow explicit memcg and NUMA node selection

Patch series "workload-specific and memory pressure-driven zswap
writeback", v8.

There are currently several issues with zswap writeback:

1. There is only a single global LRU for zswap, making it impossible to
perform worload-specific shrinking - an memcg under memory pressure
cannot determine which pages in the pool it owns, and often ends up
writing pages from other memcgs. This issue has been previously
observed in practice and mitigated by simply disabling
memcg-initiated shrinking:

https://lore.kernel.org/all/20230530232435.3097106-1-nphamcs@gmail.com/T/#u

But this solution leaves a lot to be desired, as we still do not
have an avenue for an memcg to free up its own memory locked up in
the zswap pool.

2. We only shrink the zswap pool when the user-defined limit is hit.
This means that if we set the limit too high, cold data that are
unlikely to be used again will reside in the pool, wasting precious
memory. It is hard to predict how much zswap space will be needed
ahead of time, as this depends on the workload (specifically, on
factors such as memory access patterns and compressibility of the
memory pages).

This patch series solves these issues by separating the global zswap LRU
into per-memcg and per-NUMA LRUs, and performs workload-specific (i.e
memcg- and NUMA-aware) zswap writeback under memory pressure. The new
shrinker does not have any parameter that must be tuned by the user, and
can be opted in or out on a per-memcg basis.

As a proof of concept, we ran the following synthetic benchmark: build the
linux kernel in a memory-limited cgroup, and allocate some cold data in
tmpfs to see if the shrinker could write them out and improved the overall
performance. Depending on the amount of cold data generated, we observe
from 14% to 35% reduction in kernel CPU time used in the kernel builds.


This patch (of 6):

The interface of list_lru is based on the assumption that the list node
and the data it represents belong to the same allocated on the correct
node/memcg. While this assumption is valid for existing slab objects LRU
such as dentries and inodes, it is undocumented, and rather inflexible for
certain potential list_lru users (such as the upcoming zswap shrinker and
the THP shrinker). It has caused us a lot of issues during our
development.

This patch changes list_lru interface so that the caller must explicitly
specify numa node and memcg when adding and removing objects. The old
list_lru_add() and list_lru_del() are renamed to list_lru_add_obj() and
list_lru_del_obj(), respectively.

It also extends the list_lru API with a new function, list_lru_putback,
which undoes a previous list_lru_isolate call. Unlike list_lru_add, it
does not increment the LRU node count (as list_lru_isolate does not
decrement the node count). list_lru_putback also allows for explicit
memcg and NUMA node selection.

Link: https://lkml.kernel.org/r/20231130194023.4102148-1-nphamcs@gmail.com
Link: https://lkml.kernel.org/r/20231130194023.4102148-2-nphamcs@gmail.com
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Tested-by: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff 762321da Wed Oct 25 08:10:17 MDT 2023 Christoph Hellwig <hch@lst.de> filemap: add a per-mapping stable writes flag

folio_wait_stable waits for writeback to finish before modifying the
contents of a folio again, e.g. to support check summing of the data
in the block integrity code.

Currently this behavior is controlled by the SB_I_STABLE_WRITES flag
on the super_block, which means it is uniform for the entire file system.
This is wrong for the block device pseudofs which is shared by all
block devices, or file systems that can use multiple devices like XFS
witht the RT subvolume or btrfs (although btrfs currently reimplements
folio_wait_stable anyway).

Add a per-address_space AS_STABLE_WRITES flag to control the behavior
in a more fine grained way. The existing SB_I_STABLE_WRITES is kept
to initialize AS_STABLE_WRITES to the existing default which covers
most cases.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20231025141020.192413-2-hch@lst.de
Tested-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff 16a94965 Wed Oct 04 12:52:38 MDT 2023 Jeff Layton <jlayton@kernel.org> fs: convert core infrastructure to new timestamp accessors

Convert the core vfs code to use the new timestamp accessor functions.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20231004185239.80830-2-jlayton@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff 3e15dcf7 Fri Sep 08 07:28:59 MDT 2023 Amir Goldstein <amir73il@gmail.com> fs: rename __mnt_{want,drop}_write*() helpers

Before exporting these helpers to modules, make their names more
meaningful.

The names mnt_{get,put)_write_access*() were chosen, because they rhyme
with the inode {get,put)_write_access() helpers, which have a very close
meaning for the inode object.

Suggested-by: Christian Brauner <brauner@kernel.org>
Link: https://lore.kernel.org/r/20230817-anfechtbar-ruhelosigkeit-8c6cca8443fc@brauner/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Message-Id: <20230908132900.2983519-2-amir73il@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff 9b6304c1 Wed Jul 05 12:58:10 MDT 2023 Jeff Layton <jlayton@kernel.org> fs: add ctime accessors infrastructure

struct timespec64 has unused bits in the tv_nsec field that can be used
for other purposes. In future patches, we're going to change how the
inode->i_ctime is accessed in certain inodes in order to make use of
them. In order to do that safely though, we'll need to eradicate raw
accesses of the inode->i_ctime field from the kernel.

Add new accessor functions for the ctime that we use to replace them.

Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Message-Id: <20230705185812.579118-2-jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff 33ab231f Mon Jul 03 08:49:12 MDT 2023 Christian Brauner <brauner@kernel.org> fs: don't assume arguments are non-NULL

The helper is explicitly documented as locking zero, one, or two
arguments. While all current callers do pass non-NULL arguments there's
no need or requirement for them to do so according to the code and the
unlock_two_nondirectories() helper is pretty clear about it as well. So
only call WARN_ON_ONCE() if the checked inode is valid.

Fixes: 2454ad83b90a ("fs: Restrict lock_two_nondirectories() to non-directory inodes")
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Jan Kara <jack@suse.cz>
Message-Id: <20230703-vfs-rename-source-v1-2-37eebb29b65b@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
/linux-master/fs/btrfs/
H A Dinode.cdiff 74e97958 Thu Mar 21 11:02:04 MDT 2024 Boris Burkov <boris@bur.io> btrfs: qgroup: fix qgroup prealloc rsv leak in subvolume operations

Create subvolume, create snapshot and delete subvolume all use
btrfs_subvolume_reserve_metadata() to reserve metadata for the changes
done to the parent subvolume's fs tree, which cannot be mediated in the
normal way via start_transaction. When quota groups (squota or qgroups)
are enabled, this reserves qgroup metadata of type PREALLOC. Once the
operation is associated to a transaction, we convert PREALLOC to
PERTRANS, which gets cleared in bulk at the end of the transaction.

However, the error paths of these three operations were not implementing
this lifecycle correctly. They unconditionally converted the PREALLOC to
PERTRANS in a generic cleanup step regardless of errors or whether the
operation was fully associated to a transaction or not. This resulted in
error paths occasionally converting this rsv to PERTRANS without calling
record_root_in_trans successfully, which meant that unless that root got
recorded in the transaction by some other thread, the end of the
transaction would not free that root's PERTRANS, leaking it. Ultimately,
this resulted in hitting a WARN in CONFIG_BTRFS_DEBUG builds at unmount
for the leaked reservation.

The fix is to ensure that every qgroup PREALLOC reservation observes the
following properties:

1. any failure before record_root_in_trans is called successfully
results in freeing the PREALLOC reservation.
2. after record_root_in_trans, we convert to PERTRANS, and now the
transaction owns freeing the reservation.

This patch enforces those properties on the three operations. Without
it, generic/269 with squotas enabled at mkfs time would fail in ~5-10
runs on my system. With this patch, it ran successfully 1000 times in a
row.

Fixes: e85fde5162bf ("btrfs: qgroup: fix qgroup meta rsv leak for subvolume operations")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
diff 2b712e3b Thu Jan 25 09:44:47 MST 2024 David Sterba <dsterba@suse.com> btrfs: remove unused included headers

With help of neovim, LSP and clangd we can identify header files that
are not actually needed to be included in the .c files. This is focused
only on removal (with minor fixups), further cleanups are possible but
will require doing the header files properly with forward declarations,
minimized includes and include-what-you-use care.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff 1bd96c92 Thu Feb 01 17:09:22 MST 2024 Filipe Manana <fdmanana@suse.com> btrfs: reject encoded write if inode has nodatasum flag set

Currently we allow an encoded write against inodes that have the NODATASUM
flag set, either because they are NOCOW files or they were created while
the filesystem was mounted with "-o nodatasum". This results in having
compressed extents without corresponding checksums, which is a filesystem
inconsistency reported by 'btrfs check'.

For example, running btrfs/281 with MOUNT_OPTIONS="-o nodatacow" triggers
this and 'btrfs check' errors out with:

[1/7] checking root items
[2/7] checking extents
[3/7] checking free space tree
[4/7] checking fs roots
root 256 inode 257 errors 1040, bad file extent, some csum missing
root 256 inode 258 errors 1040, bad file extent, some csum missing
ERROR: errors found in fs roots
(...)

So reject encoded writes if the target inode has NODATASUM set.

CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff 3324d054 Thu Jan 04 12:48:47 MST 2024 Omar Sandoval <osandov@fb.com> btrfs: avoid copying BTRFS_ROOT_SUBVOL_DEAD flag to snapshot of subvolume being deleted

Sweet Tea spotted a race between subvolume deletion and snapshotting
that can result in the root item for the snapshot having the
BTRFS_ROOT_SUBVOL_DEAD flag set. The race is:

Thread 1 | Thread 2
----------------------------------------------|----------
btrfs_delete_subvolume |
btrfs_set_root_flags(BTRFS_ROOT_SUBVOL_DEAD)|
|btrfs_mksubvol
| down_read(subvol_sem)
| create_snapshot
| ...
| create_pending_snapshot
| copy root item from source
down_write(subvol_sem) |

This flag is only checked in send and swap activate, which this would
cause to fail mysteriously.

create_snapshot() now checks the root refs to reject a deleted
subvolume, so we can fix this by locking subvol_sem earlier so that the
BTRFS_ROOT_SUBVOL_DEAD flag and the root refs are updated atomically.

CC: stable@vger.kernel.org # 4.14+
Reported-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Reviewed-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff 00deaf04 Mon Dec 04 09:20:29 MST 2023 Filipe Manana <fdmanana@suse.com> btrfs: log messages at unpin_extent_range() during unexpected cases

At unpin_extent_range() we trigger a WARN_ON() when we don't find an
extent map or we find one with a start offset not matching the start
offset of the target range. This however isn't very useful for debugging
because:

1) We don't know which condition was triggered, as they are both in the
same WARN_ON() call;

2) We don't know which inode was affected, from which root, for which
range, what's the start offset of the extent map, and so on.

So trigger a separate warning for each case and log a message for each
case providing information about the inode, its root, the target range,
the generation and the start offset of the extent map we found.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff 7dc66abb Tue Nov 21 06:38:38 MST 2023 Filipe Manana <fdmanana@suse.com> btrfs: use a dedicated data structure for chunk maps

Currently we abuse the extent_map structure for two purposes:

1) To actually represent extents for inodes;
2) To represent chunk mappings.

This is odd and has several disadvantages:

1) To create a chunk map, we need to do two memory allocations: one for
an extent_map structure and another one for a map_lookup structure, so
more potential for an allocation failure and more complicated code to
manage and link two structures;

2) For a chunk map we actually only use 3 fields (24 bytes) of the
respective extent map structure: the 'start' field to have the logical
start address of the chunk, the 'len' field to have the chunk's size,
and the 'orig_block_len' field to contain the chunk's stripe size.

Besides wasting a memory, it's also odd and not intuitive at all to
have the stripe size in a field named 'orig_block_len'.

We are also using 'block_len' of the extent_map structure to contain
the chunk size, so we have 2 fields for the same value, 'len' and
'block_len', which is pointless;

3) When an extent map is associated to a chunk mapping, we set the bit
EXTENT_FLAG_FS_MAPPING on its flags and then make its member named
'map_lookup' point to the associated map_lookup structure. This means
that for an extent map associated to an inode extent, we are not using
this 'map_lookup' pointer, so wasting 8 bytes (on a 64 bits platform);

4) Extent maps associated to a chunk mapping are never merged or split so
it's pointless to use the existing extent map infrastructure.

So add a dedicated data structure named 'btrfs_chunk_map' to represent
chunk mappings, this is basically the existing map_lookup structure with
some extra fields:

1) 'start' to contain the chunk logical address;
2) 'chunk_len' to contain the chunk's length;
3) 'stripe_size' for the stripe size;
4) 'rb_node' for insertion into a rb tree;
5) 'refs' for reference counting.

This way we do a single memory allocation for chunk mappings and we don't
waste memory for them with unused/unnecessary fields from an extent_map.

We also save 8 bytes from the extent_map structure by removing the
'map_lookup' pointer, so the size of struct extent_map is reduced from
144 bytes down to 136 bytes, and we can now have 30 extents map per 4K
page instead of 28.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff 7dc66abb Tue Nov 21 06:38:38 MST 2023 Filipe Manana <fdmanana@suse.com> btrfs: use a dedicated data structure for chunk maps

Currently we abuse the extent_map structure for two purposes:

1) To actually represent extents for inodes;
2) To represent chunk mappings.

This is odd and has several disadvantages:

1) To create a chunk map, we need to do two memory allocations: one for
an extent_map structure and another one for a map_lookup structure, so
more potential for an allocation failure and more complicated code to
manage and link two structures;

2) For a chunk map we actually only use 3 fields (24 bytes) of the
respective extent map structure: the 'start' field to have the logical
start address of the chunk, the 'len' field to have the chunk's size,
and the 'orig_block_len' field to contain the chunk's stripe size.

Besides wasting a memory, it's also odd and not intuitive at all to
have the stripe size in a field named 'orig_block_len'.

We are also using 'block_len' of the extent_map structure to contain
the chunk size, so we have 2 fields for the same value, 'len' and
'block_len', which is pointless;

3) When an extent map is associated to a chunk mapping, we set the bit
EXTENT_FLAG_FS_MAPPING on its flags and then make its member named
'map_lookup' point to the associated map_lookup structure. This means
that for an extent map associated to an inode extent, we are not using
this 'map_lookup' pointer, so wasting 8 bytes (on a 64 bits platform);

4) Extent maps associated to a chunk mapping are never merged or split so
it's pointless to use the existing extent map infrastructure.

So add a dedicated data structure named 'btrfs_chunk_map' to represent
chunk mappings, this is basically the existing map_lookup structure with
some extra fields:

1) 'start' to contain the chunk logical address;
2) 'chunk_len' to contain the chunk's length;
3) 'stripe_size' for the stripe size;
4) 'rb_node' for insertion into a rb tree;
5) 'refs' for reference counting.

This way we do a single memory allocation for chunk mappings and we don't
waste memory for them with unused/unnecessary fields from an extent_map.

We also save 8 bytes from the extent_map structure by removing the
'map_lookup' pointer, so the size of struct extent_map is reduced from
144 bytes down to 136 bytes, and we can now have 30 extents map per 4K
page instead of 28.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff 7dc66abb Tue Nov 21 06:38:38 MST 2023 Filipe Manana <fdmanana@suse.com> btrfs: use a dedicated data structure for chunk maps

Currently we abuse the extent_map structure for two purposes:

1) To actually represent extents for inodes;
2) To represent chunk mappings.

This is odd and has several disadvantages:

1) To create a chunk map, we need to do two memory allocations: one for
an extent_map structure and another one for a map_lookup structure, so
more potential for an allocation failure and more complicated code to
manage and link two structures;

2) For a chunk map we actually only use 3 fields (24 bytes) of the
respective extent map structure: the 'start' field to have the logical
start address of the chunk, the 'len' field to have the chunk's size,
and the 'orig_block_len' field to contain the chunk's stripe size.

Besides wasting a memory, it's also odd and not intuitive at all to
have the stripe size in a field named 'orig_block_len'.

We are also using 'block_len' of the extent_map structure to contain
the chunk size, so we have 2 fields for the same value, 'len' and
'block_len', which is pointless;

3) When an extent map is associated to a chunk mapping, we set the bit
EXTENT_FLAG_FS_MAPPING on its flags and then make its member named
'map_lookup' point to the associated map_lookup structure. This means
that for an extent map associated to an inode extent, we are not using
this 'map_lookup' pointer, so wasting 8 bytes (on a 64 bits platform);

4) Extent maps associated to a chunk mapping are never merged or split so
it's pointless to use the existing extent map infrastructure.

So add a dedicated data structure named 'btrfs_chunk_map' to represent
chunk mappings, this is basically the existing map_lookup structure with
some extra fields:

1) 'start' to contain the chunk logical address;
2) 'chunk_len' to contain the chunk's length;
3) 'stripe_size' for the stripe size;
4) 'rb_node' for insertion into a rb tree;
5) 'refs' for reference counting.

This way we do a single memory allocation for chunk mappings and we don't
waste memory for them with unused/unnecessary fields from an extent_map.

We also save 8 bytes from the extent_map structure by removing the
'map_lookup' pointer, so the size of struct extent_map is reduced from
144 bytes down to 136 bytes, and we can now have 30 extents map per 4K
page instead of 28.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff 7dc66abb Tue Nov 21 06:38:38 MST 2023 Filipe Manana <fdmanana@suse.com> btrfs: use a dedicated data structure for chunk maps

Currently we abuse the extent_map structure for two purposes:

1) To actually represent extents for inodes;
2) To represent chunk mappings.

This is odd and has several disadvantages:

1) To create a chunk map, we need to do two memory allocations: one for
an extent_map structure and another one for a map_lookup structure, so
more potential for an allocation failure and more complicated code to
manage and link two structures;

2) For a chunk map we actually only use 3 fields (24 bytes) of the
respective extent map structure: the 'start' field to have the logical
start address of the chunk, the 'len' field to have the chunk's size,
and the 'orig_block_len' field to contain the chunk's stripe size.

Besides wasting a memory, it's also odd and not intuitive at all to
have the stripe size in a field named 'orig_block_len'.

We are also using 'block_len' of the extent_map structure to contain
the chunk size, so we have 2 fields for the same value, 'len' and
'block_len', which is pointless;

3) When an extent map is associated to a chunk mapping, we set the bit
EXTENT_FLAG_FS_MAPPING on its flags and then make its member named
'map_lookup' point to the associated map_lookup structure. This means
that for an extent map associated to an inode extent, we are not using
this 'map_lookup' pointer, so wasting 8 bytes (on a 64 bits platform);

4) Extent maps associated to a chunk mapping are never merged or split so
it's pointless to use the existing extent map infrastructure.

So add a dedicated data structure named 'btrfs_chunk_map' to represent
chunk mappings, this is basically the existing map_lookup structure with
some extra fields:

1) 'start' to contain the chunk logical address;
2) 'chunk_len' to contain the chunk's length;
3) 'stripe_size' for the stripe size;
4) 'rb_node' for insertion into a rb tree;
5) 'refs' for reference counting.

This way we do a single memory allocation for chunk mappings and we don't
waste memory for them with unused/unnecessary fields from an extent_map.

We also save 8 bytes from the extent_map structure by removing the
'map_lookup' pointer, so the size of struct extent_map is reduced from
144 bytes down to 136 bytes, and we can now have 30 extents map per 4K
page instead of 28.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff 776a838f Tue Oct 17 02:00:31 MDT 2023 Naohiro Aota <naohiro.aota@wdc.com> btrfs: zoned: wait for data BG to be finished on direct IO allocation

Running the fio command below on a ZNS device results in "Resource
temporarily unavailable" error.

$ sudo fio --name=w --directory=/mnt --filesize=1GB --bs=16MB --numjobs=16 \
--rw=write --ioengine=libaio --iodepth=128 --direct=1

fio: io_u error on file /mnt/w.2.0: Resource temporarily unavailable: write offset=117440512, buflen=16777216
fio: io_u error on file /mnt/w.2.0: Resource temporarily unavailable: write offset=134217728, buflen=16777216
...

This happens because -EAGAIN error returned from btrfs_reserve_extent()
called from btrfs_new_extent_direct() is spilling over to the userland.

btrfs_reserve_extent() returns -EAGAIN when there is no active zone
available. Then, the caller should wait for some other on-going IO to
finish a zone and retry the allocation.

This logic is already implemented for buffered write in cow_file_range(),
but it is missing for the direct IO counterpart. Implement the same logic
for it.

Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Fixes: 2ce543f47843 ("btrfs: zoned: wait until zone is finished when allocation didn't progress")
CC: stable@vger.kernel.org # 6.1+
Tested-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
/linux-master/fs/cachefiles/
H A Dinterface.cdiff 1f08c925 Thu Oct 21 01:50:10 MDT 2021 David Howells <dhowells@redhat.com> cachefiles: Implement backing file wrangling

Implement the wrangling of backing files, including the following pieces:

(1) Lookup and creation of a file on disk, using a tmpfile if the file
isn't yet present. The file is then opened, sized for DIO and the
file handle is attached to the cachefiles_object struct. The inode is
marked to indicate that it's in use by a kernel service.

(2) Invalidation of an object, creating a tmpfile and switching the file
pointer in the cachefiles object.

(3) Committing a file to disk, including setting the coherency xattr on it
and, if necessary, creating a hard link to it.

Note that this would be a good place to use Omar Sandoval's vfs_link()
with AT_LINK_REPLACE[1] as I may have to unlink an old file before I
can link a tmpfile into place.

(4) Withdrawal of open objects when a cache is being withdrawn or a cookie
is relinquished. This involves committing or discarding the file.

Changes
=======
ver #2:
- Fix logging of wrong error[1].

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/20211203094950.GA2480@kili/ [1]
Link: https://lore.kernel.org/r/163819644097.215744.4505389616742411239.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906949512.143852.14222856795032602080.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967158526.1823006.17482695321424642675.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021557060.640689.16373541458119269871.stgit@warthog.procyon.org.uk/ # v4
diff 1f08c925 Thu Oct 21 01:50:10 MDT 2021 David Howells <dhowells@redhat.com> cachefiles: Implement backing file wrangling

Implement the wrangling of backing files, including the following pieces:

(1) Lookup and creation of a file on disk, using a tmpfile if the file
isn't yet present. The file is then opened, sized for DIO and the
file handle is attached to the cachefiles_object struct. The inode is
marked to indicate that it's in use by a kernel service.

(2) Invalidation of an object, creating a tmpfile and switching the file
pointer in the cachefiles object.

(3) Committing a file to disk, including setting the coherency xattr on it
and, if necessary, creating a hard link to it.

Note that this would be a good place to use Omar Sandoval's vfs_link()
with AT_LINK_REPLACE[1] as I may have to unlink an old file before I
can link a tmpfile into place.

(4) Withdrawal of open objects when a cache is being withdrawn or a cookie
is relinquished. This involves committing or discarding the file.

Changes
=======
ver #2:
- Fix logging of wrong error[1].

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/20211203094950.GA2480@kili/ [1]
Link: https://lore.kernel.org/r/163819644097.215744.4505389616742411239.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906949512.143852.14222856795032602080.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967158526.1823006.17482695321424642675.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021557060.640689.16373541458119269871.stgit@warthog.procyon.org.uk/ # v4
diff d1065b0a Fri Nov 26 07:29:06 MST 2021 David Howells <dhowells@redhat.com> cachefiles: Implement cache registration and withdrawal

Do the following:

(1) Fill out cachefiles_daemon_add_cache() so that it sets up the cache
directories and registers the cache with cachefiles.

(2) Add a function to do the top-level part of cache withdrawal and
unregistration.

(3) Add a function to sync a cache.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819633175.215744.10857127598041268340.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906935445.143852.15545194974036410029.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967142904.1823006.244055483596047072.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021543872.640689.14370017789605073222.stgit@warthog.procyon.org.uk/ # v4
diff 26aaeffc Mon Feb 22 04:39:47 MST 2021 David Howells <dhowells@redhat.com> fscache, cachefiles: Add alternate API to use kiocb for read/write to cache

Add an alternate API by which the cache can be accessed through a kiocb,
doing async DIO, rather than using the current API that tells the cache
where all the pages are.

The new API is intended to be used in conjunction with the netfs helper
library. A filesystem must pick one or the other and not mix them.

Filesystems wanting to use the new API must #define FSCACHE_USE_NEW_IO_API
before #including the header. This prevents them from continuing to use
the old API at the same time as there are incompatibilities in how the
PG_fscache page bit is used.

Changes:
v6:
- Provide a routine to shape a write so that the start and length can be
aligned for DIO[3].

v4:
- Use the vfs_iocb_iter_read/write() helpers[1]
- Move initial definition of fscache_begin_read_operation() here.
- Remove a commented-out line[2]
- Combine ki->term_func calls in cachefiles_read_complete()[2].
- Remove explicit NULL initialiser[2].
- Remove extern on func decl[2].
- Put in param names on func decl[2].
- Remove redundant else[2].
- Fill out the kdoc comment for fscache_begin_read_operation().
- Rename fs/fscache/page2.c to io.c to match later patches.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-and-tested-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Dave Wysochanski <dwysocha@redhat.com>
Tested-By: Marc Dionne <marc.dionne@auristor.com>
cc: Christoph Hellwig <hch@lst.de>
cc: linux-cachefs@redhat.com
cc: linux-afs@lists.infradead.org
cc: linux-nfs@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: ceph-devel@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20210216102614.GA27555@lst.de/ [1]
Link: https://lore.kernel.org/r/20210216084230.GA23669@lst.de/ [2]
Link: https://lore.kernel.org/r/161781047695.463527.7463536103593997492.stgit@warthog.procyon.org.uk/ [3]
Link: https://lore.kernel.org/r/161118142558.1232039.17993829899588971439.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/161161037850.2537118.8819808229350326503.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/161340402057.1303470.8038373593844486698.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/161539545919.286939.14573472672781434757.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/161653801477.2770958.10543270629064934227.stgit@warthog.procyon.org.uk/ # v5
Link: https://lore.kernel.org/r/161789084517.6155.12799689829859169640.stgit@warthog.procyon.org.uk/ # v6
diff 26aaeffc Mon Feb 22 04:39:47 MST 2021 David Howells <dhowells@redhat.com> fscache, cachefiles: Add alternate API to use kiocb for read/write to cache

Add an alternate API by which the cache can be accessed through a kiocb,
doing async DIO, rather than using the current API that tells the cache
where all the pages are.

The new API is intended to be used in conjunction with the netfs helper
library. A filesystem must pick one or the other and not mix them.

Filesystems wanting to use the new API must #define FSCACHE_USE_NEW_IO_API
before #including the header. This prevents them from continuing to use
the old API at the same time as there are incompatibilities in how the
PG_fscache page bit is used.

Changes:
v6:
- Provide a routine to shape a write so that the start and length can be
aligned for DIO[3].

v4:
- Use the vfs_iocb_iter_read/write() helpers[1]
- Move initial definition of fscache_begin_read_operation() here.
- Remove a commented-out line[2]
- Combine ki->term_func calls in cachefiles_read_complete()[2].
- Remove explicit NULL initialiser[2].
- Remove extern on func decl[2].
- Put in param names on func decl[2].
- Remove redundant else[2].
- Fill out the kdoc comment for fscache_begin_read_operation().
- Rename fs/fscache/page2.c to io.c to match later patches.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-and-tested-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Dave Wysochanski <dwysocha@redhat.com>
Tested-By: Marc Dionne <marc.dionne@auristor.com>
cc: Christoph Hellwig <hch@lst.de>
cc: linux-cachefs@redhat.com
cc: linux-afs@lists.infradead.org
cc: linux-nfs@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: ceph-devel@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20210216102614.GA27555@lst.de/ [1]
Link: https://lore.kernel.org/r/20210216084230.GA23669@lst.de/ [2]
Link: https://lore.kernel.org/r/161781047695.463527.7463536103593997492.stgit@warthog.procyon.org.uk/ [3]
Link: https://lore.kernel.org/r/161118142558.1232039.17993829899588971439.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/161161037850.2537118.8819808229350326503.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/161340402057.1303470.8038373593844486698.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/161539545919.286939.14573472672781434757.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/161653801477.2770958.10543270629064934227.stgit@warthog.procyon.org.uk/ # v5
Link: https://lore.kernel.org/r/161789084517.6155.12799689829859169640.stgit@warthog.procyon.org.uk/ # v6
diff 26aaeffc Mon Feb 22 04:39:47 MST 2021 David Howells <dhowells@redhat.com> fscache, cachefiles: Add alternate API to use kiocb for read/write to cache

Add an alternate API by which the cache can be accessed through a kiocb,
doing async DIO, rather than using the current API that tells the cache
where all the pages are.

The new API is intended to be used in conjunction with the netfs helper
library. A filesystem must pick one or the other and not mix them.

Filesystems wanting to use the new API must #define FSCACHE_USE_NEW_IO_API
before #including the header. This prevents them from continuing to use
the old API at the same time as there are incompatibilities in how the
PG_fscache page bit is used.

Changes:
v6:
- Provide a routine to shape a write so that the start and length can be
aligned for DIO[3].

v4:
- Use the vfs_iocb_iter_read/write() helpers[1]
- Move initial definition of fscache_begin_read_operation() here.
- Remove a commented-out line[2]
- Combine ki->term_func calls in cachefiles_read_complete()[2].
- Remove explicit NULL initialiser[2].
- Remove extern on func decl[2].
- Put in param names on func decl[2].
- Remove redundant else[2].
- Fill out the kdoc comment for fscache_begin_read_operation().
- Rename fs/fscache/page2.c to io.c to match later patches.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-and-tested-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Dave Wysochanski <dwysocha@redhat.com>
Tested-By: Marc Dionne <marc.dionne@auristor.com>
cc: Christoph Hellwig <hch@lst.de>
cc: linux-cachefs@redhat.com
cc: linux-afs@lists.infradead.org
cc: linux-nfs@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: ceph-devel@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20210216102614.GA27555@lst.de/ [1]
Link: https://lore.kernel.org/r/20210216084230.GA23669@lst.de/ [2]
Link: https://lore.kernel.org/r/161781047695.463527.7463536103593997492.stgit@warthog.procyon.org.uk/ [3]
Link: https://lore.kernel.org/r/161118142558.1232039.17993829899588971439.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/161161037850.2537118.8819808229350326503.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/161340402057.1303470.8038373593844486698.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/161539545919.286939.14573472672781434757.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/161653801477.2770958.10543270629064934227.stgit@warthog.procyon.org.uk/ # v5
Link: https://lore.kernel.org/r/161789084517.6155.12799689829859169640.stgit@warthog.procyon.org.uk/ # v6
diff 26aaeffc Mon Feb 22 04:39:47 MST 2021 David Howells <dhowells@redhat.com> fscache, cachefiles: Add alternate API to use kiocb for read/write to cache

Add an alternate API by which the cache can be accessed through a kiocb,
doing async DIO, rather than using the current API that tells the cache
where all the pages are.

The new API is intended to be used in conjunction with the netfs helper
library. A filesystem must pick one or the other and not mix them.

Filesystems wanting to use the new API must #define FSCACHE_USE_NEW_IO_API
before #including the header. This prevents them from continuing to use
the old API at the same time as there are incompatibilities in how the
PG_fscache page bit is used.

Changes:
v6:
- Provide a routine to shape a write so that the start and length can be
aligned for DIO[3].

v4:
- Use the vfs_iocb_iter_read/write() helpers[1]
- Move initial definition of fscache_begin_read_operation() here.
- Remove a commented-out line[2]
- Combine ki->term_func calls in cachefiles_read_complete()[2].
- Remove explicit NULL initialiser[2].
- Remove extern on func decl[2].
- Put in param names on func decl[2].
- Remove redundant else[2].
- Fill out the kdoc comment for fscache_begin_read_operation().
- Rename fs/fscache/page2.c to io.c to match later patches.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-and-tested-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Dave Wysochanski <dwysocha@redhat.com>
Tested-By: Marc Dionne <marc.dionne@auristor.com>
cc: Christoph Hellwig <hch@lst.de>
cc: linux-cachefs@redhat.com
cc: linux-afs@lists.infradead.org
cc: linux-nfs@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: ceph-devel@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20210216102614.GA27555@lst.de/ [1]
Link: https://lore.kernel.org/r/20210216084230.GA23669@lst.de/ [2]
Link: https://lore.kernel.org/r/161781047695.463527.7463536103593997492.stgit@warthog.procyon.org.uk/ [3]
Link: https://lore.kernel.org/r/161118142558.1232039.17993829899588971439.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/161161037850.2537118.8819808229350326503.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/161340402057.1303470.8038373593844486698.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/161539545919.286939.14573472672781434757.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/161653801477.2770958.10543270629064934227.stgit@warthog.procyon.org.uk/ # v5
Link: https://lore.kernel.org/r/161789084517.6155.12799689829859169640.stgit@warthog.procyon.org.uk/ # v6
diff 26aaeffc Mon Feb 22 04:39:47 MST 2021 David Howells <dhowells@redhat.com> fscache, cachefiles: Add alternate API to use kiocb for read/write to cache

Add an alternate API by which the cache can be accessed through a kiocb,
doing async DIO, rather than using the current API that tells the cache
where all the pages are.

The new API is intended to be used in conjunction with the netfs helper
library. A filesystem must pick one or the other and not mix them.

Filesystems wanting to use the new API must #define FSCACHE_USE_NEW_IO_API
before #including the header. This prevents them from continuing to use
the old API at the same time as there are incompatibilities in how the
PG_fscache page bit is used.

Changes:
v6:
- Provide a routine to shape a write so that the start and length can be
aligned for DIO[3].

v4:
- Use the vfs_iocb_iter_read/write() helpers[1]
- Move initial definition of fscache_begin_read_operation() here.
- Remove a commented-out line[2]
- Combine ki->term_func calls in cachefiles_read_complete()[2].
- Remove explicit NULL initialiser[2].
- Remove extern on func decl[2].
- Put in param names on func decl[2].
- Remove redundant else[2].
- Fill out the kdoc comment for fscache_begin_read_operation().
- Rename fs/fscache/page2.c to io.c to match later patches.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-and-tested-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Dave Wysochanski <dwysocha@redhat.com>
Tested-By: Marc Dionne <marc.dionne@auristor.com>
cc: Christoph Hellwig <hch@lst.de>
cc: linux-cachefs@redhat.com
cc: linux-afs@lists.infradead.org
cc: linux-nfs@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: ceph-devel@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20210216102614.GA27555@lst.de/ [1]
Link: https://lore.kernel.org/r/20210216084230.GA23669@lst.de/ [2]
Link: https://lore.kernel.org/r/161781047695.463527.7463536103593997492.stgit@warthog.procyon.org.uk/ [3]
Link: https://lore.kernel.org/r/161118142558.1232039.17993829899588971439.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/161161037850.2537118.8819808229350326503.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/161340402057.1303470.8038373593844486698.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/161539545919.286939.14573472672781434757.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/161653801477.2770958.10543270629064934227.stgit@warthog.procyon.org.uk/ # v5
Link: https://lore.kernel.org/r/161789084517.6155.12799689829859169640.stgit@warthog.procyon.org.uk/ # v6
diff 26aaeffc Mon Feb 22 04:39:47 MST 2021 David Howells <dhowells@redhat.com> fscache, cachefiles: Add alternate API to use kiocb for read/write to cache

Add an alternate API by which the cache can be accessed through a kiocb,
doing async DIO, rather than using the current API that tells the cache
where all the pages are.

The new API is intended to be used in conjunction with the netfs helper
library. A filesystem must pick one or the other and not mix them.

Filesystems wanting to use the new API must #define FSCACHE_USE_NEW_IO_API
before #including the header. This prevents them from continuing to use
the old API at the same time as there are incompatibilities in how the
PG_fscache page bit is used.

Changes:
v6:
- Provide a routine to shape a write so that the start and length can be
aligned for DIO[3].

v4:
- Use the vfs_iocb_iter_read/write() helpers[1]
- Move initial definition of fscache_begin_read_operation() here.
- Remove a commented-out line[2]
- Combine ki->term_func calls in cachefiles_read_complete()[2].
- Remove explicit NULL initialiser[2].
- Remove extern on func decl[2].
- Put in param names on func decl[2].
- Remove redundant else[2].
- Fill out the kdoc comment for fscache_begin_read_operation().
- Rename fs/fscache/page2.c to io.c to match later patches.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-and-tested-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Dave Wysochanski <dwysocha@redhat.com>
Tested-By: Marc Dionne <marc.dionne@auristor.com>
cc: Christoph Hellwig <hch@lst.de>
cc: linux-cachefs@redhat.com
cc: linux-afs@lists.infradead.org
cc: linux-nfs@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: ceph-devel@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20210216102614.GA27555@lst.de/ [1]
Link: https://lore.kernel.org/r/20210216084230.GA23669@lst.de/ [2]
Link: https://lore.kernel.org/r/161781047695.463527.7463536103593997492.stgit@warthog.procyon.org.uk/ [3]
Link: https://lore.kernel.org/r/161118142558.1232039.17993829899588971439.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/161161037850.2537118.8819808229350326503.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/161340402057.1303470.8038373593844486698.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/161539545919.286939.14573472672781434757.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/161653801477.2770958.10543270629064934227.stgit@warthog.procyon.org.uk/ # v5
Link: https://lore.kernel.org/r/161789084517.6155.12799689829859169640.stgit@warthog.procyon.org.uk/ # v6
diff 26aaeffc Mon Feb 22 04:39:47 MST 2021 David Howells <dhowells@redhat.com> fscache, cachefiles: Add alternate API to use kiocb for read/write to cache

Add an alternate API by which the cache can be accessed through a kiocb,
doing async DIO, rather than using the current API that tells the cache
where all the pages are.

The new API is intended to be used in conjunction with the netfs helper
library. A filesystem must pick one or the other and not mix them.

Filesystems wanting to use the new API must #define FSCACHE_USE_NEW_IO_API
before #including the header. This prevents them from continuing to use
the old API at the same time as there are incompatibilities in how the
PG_fscache page bit is used.

Changes:
v6:
- Provide a routine to shape a write so that the start and length can be
aligned for DIO[3].

v4:
- Use the vfs_iocb_iter_read/write() helpers[1]
- Move initial definition of fscache_begin_read_operation() here.
- Remove a commented-out line[2]
- Combine ki->term_func calls in cachefiles_read_complete()[2].
- Remove explicit NULL initialiser[2].
- Remove extern on func decl[2].
- Put in param names on func decl[2].
- Remove redundant else[2].
- Fill out the kdoc comment for fscache_begin_read_operation().
- Rename fs/fscache/page2.c to io.c to match later patches.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-and-tested-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Dave Wysochanski <dwysocha@redhat.com>
Tested-By: Marc Dionne <marc.dionne@auristor.com>
cc: Christoph Hellwig <hch@lst.de>
cc: linux-cachefs@redhat.com
cc: linux-afs@lists.infradead.org
cc: linux-nfs@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: ceph-devel@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20210216102614.GA27555@lst.de/ [1]
Link: https://lore.kernel.org/r/20210216084230.GA23669@lst.de/ [2]
Link: https://lore.kernel.org/r/161781047695.463527.7463536103593997492.stgit@warthog.procyon.org.uk/ [3]
Link: https://lore.kernel.org/r/161118142558.1232039.17993829899588971439.stgit@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/161161037850.2537118.8819808229350326503.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/161340402057.1303470.8038373593844486698.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/161539545919.286939.14573472672781434757.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/161653801477.2770958.10543270629064934227.stgit@warthog.procyon.org.uk/ # v5
Link: https://lore.kernel.org/r/161789084517.6155.12799689829859169640.stgit@warthog.procyon.org.uk/ # v6
/linux-master/fs/ceph/
H A Dinode.cdiff 100ccd18 Fri Nov 24 06:39:02 MST 2023 David Howells <dhowells@redhat.com> netfs: Optimise away reads above the point at which there can be no data

Track the file position above which the server is not expected to have any
data (the "zero point") and preemptively assume that we can satisfy
requests by filling them with zeroes locally rather than attempting to
download them if they're over that line - even if we've written data back
to the server. Assume that any data that was written back above that
position is held in the local cache. Note that we have to split requests
that straddle the line.

Make use of this to optimise away some reads from the server. We need to
set the zero point in the following circumstances:

(1) When we see an extant remote inode and have no cache for it, we set
the zero_point to i_size.

(2) On local inode creation, we set zero_point to 0.

(3) On local truncation down, we reduce zero_point to the new i_size if
the new i_size is lower.

(4) On local truncation up, we don't change zero_point.

(5) On local modification, we don't change zero_point.

(6) On remote invalidation, we set zero_point to the new i_size.

(7) If stored data is discarded from the pagecache or culled from fscache,
we must set zero_point above that if the data also got written to the
server.

(8) If dirty data is written back to the server, but not fscache, we must
set zero_point above that.

(9) If a direct I/O write is made, set zero_point above that.

Assuming the above, any read from the server at or above the zero_point
position will return all zeroes.

The zero_point value can be stored in the cache, provided the above rules
are applied to it by any code that culls part of the local cache.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
diff 2d332d5b Mon Jul 27 08:16:09 MDT 2020 Jeff Layton <jlayton@kernel.org> ceph: fscrypt_auth handling for ceph

Most fscrypt-enabled filesystems store the crypto context in an xattr,
but that's problematic for ceph as xatts are governed by the XATTR cap,
but we really want the crypto context as part of the AUTH cap.

Because of this, the MDS has added two new inode metadata fields:
fscrypt_auth and fscrypt_file. The former is used to hold the crypto
context, and the latter is used to track the real file size.

Parse new fscrypt_auth and fscrypt_file fields in inode traces. For now,
we don't use fscrypt_file, but fscrypt_auth is used to hold the fscrypt
context.

Allow the client to use a setattr request for setting the fscrypt_auth
field. Since this is not a standard setattr request from the VFS, we add
a new field to __ceph_setattr that carries ceph-specific inode attrs.

Have the set_context op do a setattr that sets the fscrypt_auth value,
and get_context just return the contents of that field (since it should
always be available).

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Reviewed-and-tested-by: Luís Henriques <lhenriques@suse.de>
Reviewed-by: Milind Changire <mchangir@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
diff 0d72b928 Mon Aug 07 13:38:33 MDT 2023 Jeff Layton <jlayton@kernel.org> fs: pass the request_mask to generic_fillattr

generic_fillattr just fills in the entire stat struct indiscriminately
today, copying data from the inode. There is at least one attribute
(STATX_CHANGE_COOKIE) that can have side effects when it is reported,
and we're looking at adding more with the addition of multigrain
timestamps.

Add a request_mask argument to generic_fillattr and have most callers
just pass in the value that is passed to getattr. Have other callers
(e.g. ksmbd) just pass in STATX_BASIC_STATS. Also move the setting of
STATX_CHANGE_COOKIE into generic_fillattr.

Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: "Paulo Alcantara (SUSE)" <pc@manguebit.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Message-Id: <20230807-mgctime-v7-2-d1dec143a704@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff 81895a65 Wed Oct 05 08:43:38 MDT 2022 Jason A. Donenfeld <Jason@zx2c4.com> treewide: use prandom_u32_max() when possible, part 1

Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
the minimum required bytes from the RNG and avoids divisions. This was
done mechanically with this coccinelle script:

@basic@
expression E;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u64;
@@
(
- ((T)get_random_u32() % (E))
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ((E) - 1))
+ prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2)
|
- ((u64)(E) * get_random_u32() >> 32)
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ~PAGE_MASK)
+ prandom_u32_max(PAGE_SIZE)
)

@multi_line@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
identifier RAND;
expression E;
@@

- RAND = get_random_u32();
... when != RAND
- RAND %= (E);
+ RAND = prandom_u32_max(E);

// Find a potential literal
@literal_mask@
expression LITERAL;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
position p;
@@

((T)get_random_u32()@p & (LITERAL))

// Add one to the literal.
@script:python add_one@
literal << literal_mask.LITERAL;
RESULT;
@@

value = None
if literal.startswith('0x'):
value = int(literal, 16)
elif literal[0] in '123456789':
value = int(literal, 10)
if value is None:
print("I don't know how to handle %s" % (literal))
cocci.include_match(False)
elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1:
print("Skipping 0x%x for cleanup elsewhere" % (value))
cocci.include_match(False)
elif value & (value + 1) != 0:
print("Skipping 0x%x because it's not a power of two minus one" % (value))
cocci.include_match(False)
elif literal.startswith('0x'):
coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1))
else:
coccinelle.RESULT = cocci.make_expr("%d" % (value + 1))

// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
expression add_one.RESULT;
identifier FUNC;
@@

- (FUNC()@p & (LITERAL))
+ prandom_u32_max(RESULT)

@collapse_ret@
type T;
identifier VAR;
expression E;
@@

{
- T VAR;
- VAR = (E);
- return VAR;
+ return E;
}

@drop_var@
type T;
identifier VAR;
@@

{
- T VAR;
... when != VAR
}

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: KP Singh <kpsingh@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> # for drbd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
diff 81895a65 Wed Oct 05 08:43:38 MDT 2022 Jason A. Donenfeld <Jason@zx2c4.com> treewide: use prandom_u32_max() when possible, part 1

Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
the minimum required bytes from the RNG and avoids divisions. This was
done mechanically with this coccinelle script:

@basic@
expression E;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u64;
@@
(
- ((T)get_random_u32() % (E))
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ((E) - 1))
+ prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2)
|
- ((u64)(E) * get_random_u32() >> 32)
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ~PAGE_MASK)
+ prandom_u32_max(PAGE_SIZE)
)

@multi_line@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
identifier RAND;
expression E;
@@

- RAND = get_random_u32();
... when != RAND
- RAND %= (E);
+ RAND = prandom_u32_max(E);

// Find a potential literal
@literal_mask@
expression LITERAL;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
position p;
@@

((T)get_random_u32()@p & (LITERAL))

// Add one to the literal.
@script:python add_one@
literal << literal_mask.LITERAL;
RESULT;
@@

value = None
if literal.startswith('0x'):
value = int(literal, 16)
elif literal[0] in '123456789':
value = int(literal, 10)
if value is None:
print("I don't know how to handle %s" % (literal))
cocci.include_match(False)
elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1:
print("Skipping 0x%x for cleanup elsewhere" % (value))
cocci.include_match(False)
elif value & (value + 1) != 0:
print("Skipping 0x%x because it's not a power of two minus one" % (value))
cocci.include_match(False)
elif literal.startswith('0x'):
coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1))
else:
coccinelle.RESULT = cocci.make_expr("%d" % (value + 1))

// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
expression add_one.RESULT;
identifier FUNC;
@@

- (FUNC()@p & (LITERAL))
+ prandom_u32_max(RESULT)

@collapse_ret@
type T;
identifier VAR;
expression E;
@@

{
- T VAR;
- VAR = (E);
- return VAR;
+ return E;
}

@drop_var@
type T;
identifier VAR;
@@

{
- T VAR;
... when != VAR
}

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: KP Singh <kpsingh@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> # for drbd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
diff 81895a65 Wed Oct 05 08:43:38 MDT 2022 Jason A. Donenfeld <Jason@zx2c4.com> treewide: use prandom_u32_max() when possible, part 1

Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
the minimum required bytes from the RNG and avoids divisions. This was
done mechanically with this coccinelle script:

@basic@
expression E;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u64;
@@
(
- ((T)get_random_u32() % (E))
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ((E) - 1))
+ prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2)
|
- ((u64)(E) * get_random_u32() >> 32)
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ~PAGE_MASK)
+ prandom_u32_max(PAGE_SIZE)
)

@multi_line@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
identifier RAND;
expression E;
@@

- RAND = get_random_u32();
... when != RAND
- RAND %= (E);
+ RAND = prandom_u32_max(E);

// Find a potential literal
@literal_mask@
expression LITERAL;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
position p;
@@

((T)get_random_u32()@p & (LITERAL))

// Add one to the literal.
@script:python add_one@
literal << literal_mask.LITERAL;
RESULT;
@@

value = None
if literal.startswith('0x'):
value = int(literal, 16)
elif literal[0] in '123456789':
value = int(literal, 10)
if value is None:
print("I don't know how to handle %s" % (literal))
cocci.include_match(False)
elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1:
print("Skipping 0x%x for cleanup elsewhere" % (value))
cocci.include_match(False)
elif value & (value + 1) != 0:
print("Skipping 0x%x because it's not a power of two minus one" % (value))
cocci.include_match(False)
elif literal.startswith('0x'):
coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1))
else:
coccinelle.RESULT = cocci.make_expr("%d" % (value + 1))

// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
expression add_one.RESULT;
identifier FUNC;
@@

- (FUNC()@p & (LITERAL))
+ prandom_u32_max(RESULT)

@collapse_ret@
type T;
identifier VAR;
expression E;
@@

{
- T VAR;
- VAR = (E);
- return VAR;
+ return E;
}

@drop_var@
type T;
identifier VAR;
@@

{
- T VAR;
... when != VAR
}

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: KP Singh <kpsingh@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> # for drbd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
diff 81895a65 Wed Oct 05 08:43:38 MDT 2022 Jason A. Donenfeld <Jason@zx2c4.com> treewide: use prandom_u32_max() when possible, part 1

Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
the minimum required bytes from the RNG and avoids divisions. This was
done mechanically with this coccinelle script:

@basic@
expression E;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u64;
@@
(
- ((T)get_random_u32() % (E))
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ((E) - 1))
+ prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2)
|
- ((u64)(E) * get_random_u32() >> 32)
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ~PAGE_MASK)
+ prandom_u32_max(PAGE_SIZE)
)

@multi_line@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
identifier RAND;
expression E;
@@

- RAND = get_random_u32();
... when != RAND
- RAND %= (E);
+ RAND = prandom_u32_max(E);

// Find a potential literal
@literal_mask@
expression LITERAL;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
position p;
@@

((T)get_random_u32()@p & (LITERAL))

// Add one to the literal.
@script:python add_one@
literal << literal_mask.LITERAL;
RESULT;
@@

value = None
if literal.startswith('0x'):
value = int(literal, 16)
elif literal[0] in '123456789':
value = int(literal, 10)
if value is None:
print("I don't know how to handle %s" % (literal))
cocci.include_match(False)
elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1:
print("Skipping 0x%x for cleanup elsewhere" % (value))
cocci.include_match(False)
elif value & (value + 1) != 0:
print("Skipping 0x%x because it's not a power of two minus one" % (value))
cocci.include_match(False)
elif literal.startswith('0x'):
coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1))
else:
coccinelle.RESULT = cocci.make_expr("%d" % (value + 1))

// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
expression add_one.RESULT;
identifier FUNC;
@@

- (FUNC()@p & (LITERAL))
+ prandom_u32_max(RESULT)

@collapse_ret@
type T;
identifier VAR;
expression E;
@@

{
- T VAR;
- VAR = (E);
- return VAR;
+ return E;
}

@drop_var@
type T;
identifier VAR;
@@

{
- T VAR;
... when != VAR
}

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: KP Singh <kpsingh@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> # for drbd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
diff 81895a65 Wed Oct 05 08:43:38 MDT 2022 Jason A. Donenfeld <Jason@zx2c4.com> treewide: use prandom_u32_max() when possible, part 1

Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
the minimum required bytes from the RNG and avoids divisions. This was
done mechanically with this coccinelle script:

@basic@
expression E;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u64;
@@
(
- ((T)get_random_u32() % (E))
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ((E) - 1))
+ prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2)
|
- ((u64)(E) * get_random_u32() >> 32)
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ~PAGE_MASK)
+ prandom_u32_max(PAGE_SIZE)
)

@multi_line@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
identifier RAND;
expression E;
@@

- RAND = get_random_u32();
... when != RAND
- RAND %= (E);
+ RAND = prandom_u32_max(E);

// Find a potential literal
@literal_mask@
expression LITERAL;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
position p;
@@

((T)get_random_u32()@p & (LITERAL))

// Add one to the literal.
@script:python add_one@
literal << literal_mask.LITERAL;
RESULT;
@@

value = None
if literal.startswith('0x'):
value = int(literal, 16)
elif literal[0] in '123456789':
value = int(literal, 10)
if value is None:
print("I don't know how to handle %s" % (literal))
cocci.include_match(False)
elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1:
print("Skipping 0x%x for cleanup elsewhere" % (value))
cocci.include_match(False)
elif value & (value + 1) != 0:
print("Skipping 0x%x because it's not a power of two minus one" % (value))
cocci.include_match(False)
elif literal.startswith('0x'):
coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1))
else:
coccinelle.RESULT = cocci.make_expr("%d" % (value + 1))

// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
expression add_one.RESULT;
identifier FUNC;
@@

- (FUNC()@p & (LITERAL))
+ prandom_u32_max(RESULT)

@collapse_ret@
type T;
identifier VAR;
expression E;
@@

{
- T VAR;
- VAR = (E);
- return VAR;
+ return E;
}

@drop_var@
type T;
identifier VAR;
@@

{
- T VAR;
... when != VAR
}

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: KP Singh <kpsingh@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> # for drbd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
diff 874c8ca1 Thu Jun 09 14:46:04 MDT 2022 David Howells <dhowells@redhat.com> netfs: Fix gcc-12 warning by embedding vfs inode in netfs_i_context

While randstruct was satisfied with using an open-coded "void *" offset
cast for the netfs_i_context <-> inode casting, __builtin_object_size() as
used by FORTIFY_SOURCE was not as easily fooled. This was causing the
following complaint[1] from gcc v12:

In file included from include/linux/string.h:253,
from include/linux/ceph/ceph_debug.h:7,
from fs/ceph/inode.c:2:
In function 'fortify_memset_chk',
inlined from 'netfs_i_context_init' at include/linux/netfs.h:326:2,
inlined from 'ceph_alloc_inode' at fs/ceph/inode.c:463:2:
include/linux/fortify-string.h:242:25: warning: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning]
242 | __write_overflow_field(p_size_field, size);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fix this by embedding a struct inode into struct netfs_i_context (which
should perhaps be renamed to struct netfs_inode). The struct inode
vfs_inode fields are then removed from the 9p, afs, ceph and cifs inode
structs and vfs_inode is then simply changed to "netfs.inode" in those
filesystems.

Further, rename netfs_i_context to netfs_inode, get rid of the
netfs_inode() function that converted a netfs_i_context pointer to an
inode pointer (that can now be done with &ctx->inode) and rename the
netfs_i_context() function to netfs_inode() (which is now a wrapper
around container_of()).

Most of the changes were done with:

perl -p -i -e 's/vfs_inode/netfs.inode/'g \
`git grep -l 'vfs_inode' -- fs/{9p,afs,ceph,cifs}/*.[ch]`

Kees suggested doing it with a pair structure[2] and a special
declarator to insert that into the network filesystem's inode
wrapper[3], but I think it's cleaner to embed it - and then it doesn't
matter if struct randomisation reorders things.

Dave Chinner suggested using a filesystem-specific VFS_I() function in
each filesystem to convert that filesystem's own inode wrapper struct
into the VFS inode struct[4].

Version #2:
- Fix a couple of missed name changes due to a disabled cifs option.
- Rename nfs_i_context to nfs_inode
- Use "netfs" instead of "nic" as the member name in per-fs inode wrapper
structs.

[ This also undoes commit 507160f46c55 ("netfs: gcc-12: temporarily
disable '-Wattribute-warning' for now") that is no longer needed ]

Fixes: bc899ee1c898 ("netfs: Add a netfs inode context")
Reported-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
cc: Jonathan Corbet <corbet@lwn.net>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Steve French <smfrench@gmail.com>
cc: William Kucharski <william.kucharski@oracle.com>
cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
cc: Dave Chinner <david@fromorbit.com>
cc: linux-doc@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: samba-technical@lists.samba.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-hardening@vger.kernel.org
Link: https://lore.kernel.org/r/d2ad3a3d7bdd794c6efb562d2f2b655fb67756b9.camel@kernel.org/ [1]
Link: https://lore.kernel.org/r/20220517210230.864239-1-keescook@chromium.org/ [2]
Link: https://lore.kernel.org/r/20220518202212.2322058-1-keescook@chromium.org/ [3]
Link: https://lore.kernel.org/r/20220524101205.GI2306852@dread.disaster.area/ [4]
Link: https://lore.kernel.org/r/165296786831.3591209.12111293034669289733.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165305805651.4094995.7763502506786714216.stgit@warthog.procyon.org.uk # v2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff 874c8ca1 Thu Jun 09 14:46:04 MDT 2022 David Howells <dhowells@redhat.com> netfs: Fix gcc-12 warning by embedding vfs inode in netfs_i_context

While randstruct was satisfied with using an open-coded "void *" offset
cast for the netfs_i_context <-> inode casting, __builtin_object_size() as
used by FORTIFY_SOURCE was not as easily fooled. This was causing the
following complaint[1] from gcc v12:

In file included from include/linux/string.h:253,
from include/linux/ceph/ceph_debug.h:7,
from fs/ceph/inode.c:2:
In function 'fortify_memset_chk',
inlined from 'netfs_i_context_init' at include/linux/netfs.h:326:2,
inlined from 'ceph_alloc_inode' at fs/ceph/inode.c:463:2:
include/linux/fortify-string.h:242:25: warning: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning]
242 | __write_overflow_field(p_size_field, size);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fix this by embedding a struct inode into struct netfs_i_context (which
should perhaps be renamed to struct netfs_inode). The struct inode
vfs_inode fields are then removed from the 9p, afs, ceph and cifs inode
structs and vfs_inode is then simply changed to "netfs.inode" in those
filesystems.

Further, rename netfs_i_context to netfs_inode, get rid of the
netfs_inode() function that converted a netfs_i_context pointer to an
inode pointer (that can now be done with &ctx->inode) and rename the
netfs_i_context() function to netfs_inode() (which is now a wrapper
around container_of()).

Most of the changes were done with:

perl -p -i -e 's/vfs_inode/netfs.inode/'g \
`git grep -l 'vfs_inode' -- fs/{9p,afs,ceph,cifs}/*.[ch]`

Kees suggested doing it with a pair structure[2] and a special
declarator to insert that into the network filesystem's inode
wrapper[3], but I think it's cleaner to embed it - and then it doesn't
matter if struct randomisation reorders things.

Dave Chinner suggested using a filesystem-specific VFS_I() function in
each filesystem to convert that filesystem's own inode wrapper struct
into the VFS inode struct[4].

Version #2:
- Fix a couple of missed name changes due to a disabled cifs option.
- Rename nfs_i_context to nfs_inode
- Use "netfs" instead of "nic" as the member name in per-fs inode wrapper
structs.

[ This also undoes commit 507160f46c55 ("netfs: gcc-12: temporarily
disable '-Wattribute-warning' for now") that is no longer needed ]

Fixes: bc899ee1c898 ("netfs: Add a netfs inode context")
Reported-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
cc: Jonathan Corbet <corbet@lwn.net>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Steve French <smfrench@gmail.com>
cc: William Kucharski <william.kucharski@oracle.com>
cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
cc: Dave Chinner <david@fromorbit.com>
cc: linux-doc@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: samba-technical@lists.samba.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-hardening@vger.kernel.org
Link: https://lore.kernel.org/r/d2ad3a3d7bdd794c6efb562d2f2b655fb67756b9.camel@kernel.org/ [1]
Link: https://lore.kernel.org/r/20220517210230.864239-1-keescook@chromium.org/ [2]
Link: https://lore.kernel.org/r/20220518202212.2322058-1-keescook@chromium.org/ [3]
Link: https://lore.kernel.org/r/20220524101205.GI2306852@dread.disaster.area/ [4]
Link: https://lore.kernel.org/r/165296786831.3591209.12111293034669289733.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165305805651.4094995.7763502506786714216.stgit@warthog.procyon.org.uk # v2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff 874c8ca1 Thu Jun 09 14:46:04 MDT 2022 David Howells <dhowells@redhat.com> netfs: Fix gcc-12 warning by embedding vfs inode in netfs_i_context

While randstruct was satisfied with using an open-coded "void *" offset
cast for the netfs_i_context <-> inode casting, __builtin_object_size() as
used by FORTIFY_SOURCE was not as easily fooled. This was causing the
following complaint[1] from gcc v12:

In file included from include/linux/string.h:253,
from include/linux/ceph/ceph_debug.h:7,
from fs/ceph/inode.c:2:
In function 'fortify_memset_chk',
inlined from 'netfs_i_context_init' at include/linux/netfs.h:326:2,
inlined from 'ceph_alloc_inode' at fs/ceph/inode.c:463:2:
include/linux/fortify-string.h:242:25: warning: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning]
242 | __write_overflow_field(p_size_field, size);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fix this by embedding a struct inode into struct netfs_i_context (which
should perhaps be renamed to struct netfs_inode). The struct inode
vfs_inode fields are then removed from the 9p, afs, ceph and cifs inode
structs and vfs_inode is then simply changed to "netfs.inode" in those
filesystems.

Further, rename netfs_i_context to netfs_inode, get rid of the
netfs_inode() function that converted a netfs_i_context pointer to an
inode pointer (that can now be done with &ctx->inode) and rename the
netfs_i_context() function to netfs_inode() (which is now a wrapper
around container_of()).

Most of the changes were done with:

perl -p -i -e 's/vfs_inode/netfs.inode/'g \
`git grep -l 'vfs_inode' -- fs/{9p,afs,ceph,cifs}/*.[ch]`

Kees suggested doing it with a pair structure[2] and a special
declarator to insert that into the network filesystem's inode
wrapper[3], but I think it's cleaner to embed it - and then it doesn't
matter if struct randomisation reorders things.

Dave Chinner suggested using a filesystem-specific VFS_I() function in
each filesystem to convert that filesystem's own inode wrapper struct
into the VFS inode struct[4].

Version #2:
- Fix a couple of missed name changes due to a disabled cifs option.
- Rename nfs_i_context to nfs_inode
- Use "netfs" instead of "nic" as the member name in per-fs inode wrapper
structs.

[ This also undoes commit 507160f46c55 ("netfs: gcc-12: temporarily
disable '-Wattribute-warning' for now") that is no longer needed ]

Fixes: bc899ee1c898 ("netfs: Add a netfs inode context")
Reported-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
cc: Jonathan Corbet <corbet@lwn.net>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Steve French <smfrench@gmail.com>
cc: William Kucharski <william.kucharski@oracle.com>
cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
cc: Dave Chinner <david@fromorbit.com>
cc: linux-doc@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: samba-technical@lists.samba.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-hardening@vger.kernel.org
Link: https://lore.kernel.org/r/d2ad3a3d7bdd794c6efb562d2f2b655fb67756b9.camel@kernel.org/ [1]
Link: https://lore.kernel.org/r/20220517210230.864239-1-keescook@chromium.org/ [2]
Link: https://lore.kernel.org/r/20220518202212.2322058-1-keescook@chromium.org/ [3]
Link: https://lore.kernel.org/r/20220524101205.GI2306852@dread.disaster.area/ [4]
Link: https://lore.kernel.org/r/165296786831.3591209.12111293034669289733.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165305805651.4094995.7763502506786714216.stgit@warthog.procyon.org.uk # v2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff 874c8ca1 Thu Jun 09 14:46:04 MDT 2022 David Howells <dhowells@redhat.com> netfs: Fix gcc-12 warning by embedding vfs inode in netfs_i_context

While randstruct was satisfied with using an open-coded "void *" offset
cast for the netfs_i_context <-> inode casting, __builtin_object_size() as
used by FORTIFY_SOURCE was not as easily fooled. This was causing the
following complaint[1] from gcc v12:

In file included from include/linux/string.h:253,
from include/linux/ceph/ceph_debug.h:7,
from fs/ceph/inode.c:2:
In function 'fortify_memset_chk',
inlined from 'netfs_i_context_init' at include/linux/netfs.h:326:2,
inlined from 'ceph_alloc_inode' at fs/ceph/inode.c:463:2:
include/linux/fortify-string.h:242:25: warning: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning]
242 | __write_overflow_field(p_size_field, size);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fix this by embedding a struct inode into struct netfs_i_context (which
should perhaps be renamed to struct netfs_inode). The struct inode
vfs_inode fields are then removed from the 9p, afs, ceph and cifs inode
structs and vfs_inode is then simply changed to "netfs.inode" in those
filesystems.

Further, rename netfs_i_context to netfs_inode, get rid of the
netfs_inode() function that converted a netfs_i_context pointer to an
inode pointer (that can now be done with &ctx->inode) and rename the
netfs_i_context() function to netfs_inode() (which is now a wrapper
around container_of()).

Most of the changes were done with:

perl -p -i -e 's/vfs_inode/netfs.inode/'g \
`git grep -l 'vfs_inode' -- fs/{9p,afs,ceph,cifs}/*.[ch]`

Kees suggested doing it with a pair structure[2] and a special
declarator to insert that into the network filesystem's inode
wrapper[3], but I think it's cleaner to embed it - and then it doesn't
matter if struct randomisation reorders things.

Dave Chinner suggested using a filesystem-specific VFS_I() function in
each filesystem to convert that filesystem's own inode wrapper struct
into the VFS inode struct[4].

Version #2:
- Fix a couple of missed name changes due to a disabled cifs option.
- Rename nfs_i_context to nfs_inode
- Use "netfs" instead of "nic" as the member name in per-fs inode wrapper
structs.

[ This also undoes commit 507160f46c55 ("netfs: gcc-12: temporarily
disable '-Wattribute-warning' for now") that is no longer needed ]

Fixes: bc899ee1c898 ("netfs: Add a netfs inode context")
Reported-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
cc: Jonathan Corbet <corbet@lwn.net>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Steve French <smfrench@gmail.com>
cc: William Kucharski <william.kucharski@oracle.com>
cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
cc: Dave Chinner <david@fromorbit.com>
cc: linux-doc@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: samba-technical@lists.samba.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-hardening@vger.kernel.org
Link: https://lore.kernel.org/r/d2ad3a3d7bdd794c6efb562d2f2b655fb67756b9.camel@kernel.org/ [1]
Link: https://lore.kernel.org/r/20220517210230.864239-1-keescook@chromium.org/ [2]
Link: https://lore.kernel.org/r/20220518202212.2322058-1-keescook@chromium.org/ [3]
Link: https://lore.kernel.org/r/20220524101205.GI2306852@dread.disaster.area/ [4]
Link: https://lore.kernel.org/r/165296786831.3591209.12111293034669289733.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165305805651.4094995.7763502506786714216.stgit@warthog.procyon.org.uk # v2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff 874c8ca1 Thu Jun 09 14:46:04 MDT 2022 David Howells <dhowells@redhat.com> netfs: Fix gcc-12 warning by embedding vfs inode in netfs_i_context

While randstruct was satisfied with using an open-coded "void *" offset
cast for the netfs_i_context <-> inode casting, __builtin_object_size() as
used by FORTIFY_SOURCE was not as easily fooled. This was causing the
following complaint[1] from gcc v12:

In file included from include/linux/string.h:253,
from include/linux/ceph/ceph_debug.h:7,
from fs/ceph/inode.c:2:
In function 'fortify_memset_chk',
inlined from 'netfs_i_context_init' at include/linux/netfs.h:326:2,
inlined from 'ceph_alloc_inode' at fs/ceph/inode.c:463:2:
include/linux/fortify-string.h:242:25: warning: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning]
242 | __write_overflow_field(p_size_field, size);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fix this by embedding a struct inode into struct netfs_i_context (which
should perhaps be renamed to struct netfs_inode). The struct inode
vfs_inode fields are then removed from the 9p, afs, ceph and cifs inode
structs and vfs_inode is then simply changed to "netfs.inode" in those
filesystems.

Further, rename netfs_i_context to netfs_inode, get rid of the
netfs_inode() function that converted a netfs_i_context pointer to an
inode pointer (that can now be done with &ctx->inode) and rename the
netfs_i_context() function to netfs_inode() (which is now a wrapper
around container_of()).

Most of the changes were done with:

perl -p -i -e 's/vfs_inode/netfs.inode/'g \
`git grep -l 'vfs_inode' -- fs/{9p,afs,ceph,cifs}/*.[ch]`

Kees suggested doing it with a pair structure[2] and a special
declarator to insert that into the network filesystem's inode
wrapper[3], but I think it's cleaner to embed it - and then it doesn't
matter if struct randomisation reorders things.

Dave Chinner suggested using a filesystem-specific VFS_I() function in
each filesystem to convert that filesystem's own inode wrapper struct
into the VFS inode struct[4].

Version #2:
- Fix a couple of missed name changes due to a disabled cifs option.
- Rename nfs_i_context to nfs_inode
- Use "netfs" instead of "nic" as the member name in per-fs inode wrapper
structs.

[ This also undoes commit 507160f46c55 ("netfs: gcc-12: temporarily
disable '-Wattribute-warning' for now") that is no longer needed ]

Fixes: bc899ee1c898 ("netfs: Add a netfs inode context")
Reported-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
cc: Jonathan Corbet <corbet@lwn.net>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Steve French <smfrench@gmail.com>
cc: William Kucharski <william.kucharski@oracle.com>
cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
cc: Dave Chinner <david@fromorbit.com>
cc: linux-doc@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: samba-technical@lists.samba.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-hardening@vger.kernel.org
Link: https://lore.kernel.org/r/d2ad3a3d7bdd794c6efb562d2f2b655fb67756b9.camel@kernel.org/ [1]
Link: https://lore.kernel.org/r/20220517210230.864239-1-keescook@chromium.org/ [2]
Link: https://lore.kernel.org/r/20220518202212.2322058-1-keescook@chromium.org/ [3]
Link: https://lore.kernel.org/r/20220524101205.GI2306852@dread.disaster.area/ [4]
Link: https://lore.kernel.org/r/165296786831.3591209.12111293034669289733.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165305805651.4094995.7763502506786714216.stgit@warthog.procyon.org.uk # v2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff 874c8ca1 Thu Jun 09 14:46:04 MDT 2022 David Howells <dhowells@redhat.com> netfs: Fix gcc-12 warning by embedding vfs inode in netfs_i_context

While randstruct was satisfied with using an open-coded "void *" offset
cast for the netfs_i_context <-> inode casting, __builtin_object_size() as
used by FORTIFY_SOURCE was not as easily fooled. This was causing the
following complaint[1] from gcc v12:

In file included from include/linux/string.h:253,
from include/linux/ceph/ceph_debug.h:7,
from fs/ceph/inode.c:2:
In function 'fortify_memset_chk',
inlined from 'netfs_i_context_init' at include/linux/netfs.h:326:2,
inlined from 'ceph_alloc_inode' at fs/ceph/inode.c:463:2:
include/linux/fortify-string.h:242:25: warning: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning]
242 | __write_overflow_field(p_size_field, size);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fix this by embedding a struct inode into struct netfs_i_context (which
should perhaps be renamed to struct netfs_inode). The struct inode
vfs_inode fields are then removed from the 9p, afs, ceph and cifs inode
structs and vfs_inode is then simply changed to "netfs.inode" in those
filesystems.

Further, rename netfs_i_context to netfs_inode, get rid of the
netfs_inode() function that converted a netfs_i_context pointer to an
inode pointer (that can now be done with &ctx->inode) and rename the
netfs_i_context() function to netfs_inode() (which is now a wrapper
around container_of()).

Most of the changes were done with:

perl -p -i -e 's/vfs_inode/netfs.inode/'g \
`git grep -l 'vfs_inode' -- fs/{9p,afs,ceph,cifs}/*.[ch]`

Kees suggested doing it with a pair structure[2] and a special
declarator to insert that into the network filesystem's inode
wrapper[3], but I think it's cleaner to embed it - and then it doesn't
matter if struct randomisation reorders things.

Dave Chinner suggested using a filesystem-specific VFS_I() function in
each filesystem to convert that filesystem's own inode wrapper struct
into the VFS inode struct[4].

Version #2:
- Fix a couple of missed name changes due to a disabled cifs option.
- Rename nfs_i_context to nfs_inode
- Use "netfs" instead of "nic" as the member name in per-fs inode wrapper
structs.

[ This also undoes commit 507160f46c55 ("netfs: gcc-12: temporarily
disable '-Wattribute-warning' for now") that is no longer needed ]

Fixes: bc899ee1c898 ("netfs: Add a netfs inode context")
Reported-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
cc: Jonathan Corbet <corbet@lwn.net>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Steve French <smfrench@gmail.com>
cc: William Kucharski <william.kucharski@oracle.com>
cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
cc: Dave Chinner <david@fromorbit.com>
cc: linux-doc@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: samba-technical@lists.samba.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-hardening@vger.kernel.org
Link: https://lore.kernel.org/r/d2ad3a3d7bdd794c6efb562d2f2b655fb67756b9.camel@kernel.org/ [1]
Link: https://lore.kernel.org/r/20220517210230.864239-1-keescook@chromium.org/ [2]
Link: https://lore.kernel.org/r/20220518202212.2322058-1-keescook@chromium.org/ [3]
Link: https://lore.kernel.org/r/20220524101205.GI2306852@dread.disaster.area/ [4]
Link: https://lore.kernel.org/r/165296786831.3591209.12111293034669289733.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165305805651.4094995.7763502506786714216.stgit@warthog.procyon.org.uk # v2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
/linux-master/fs/ecryptfs/
H A Dinode.cdiff 0d72b928 Mon Aug 07 13:38:33 MDT 2023 Jeff Layton <jlayton@kernel.org> fs: pass the request_mask to generic_fillattr

generic_fillattr just fills in the entire stat struct indiscriminately
today, copying data from the inode. There is at least one attribute
(STATX_CHANGE_COOKIE) that can have side effects when it is reported,
and we're looking at adding more with the addition of multigrain
timestamps.

Add a request_mask argument to generic_fillattr and have most callers
just pass in the value that is passed to getattr. Have other callers
(e.g. ksmbd) just pass in STATX_BASIC_STATS. Also move the setting of
STATX_CHANGE_COOKIE into generic_fillattr.

Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: "Paulo Alcantara (SUSE)" <pc@manguebit.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Message-Id: <20230807-mgctime-v7-2-d1dec143a704@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 1a59d1b8 Mon May 27 00:55:05 MDT 2019 Thomas Gleixner <tglx@linutronix.de> treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details you
should have received a copy of the gnu general public license along
with this program if not write to the free software foundation inc
59 temple place suite 330 boston ma 02111 1307 usa

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1334 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff a528d35e Tue Jan 31 09:46:22 MST 2017 David Howells <dhowells@redhat.com> statx: Add a system call to make enhanced file info available

Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.

The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode. This change is propagated to the vfs_getattr*()
function.

Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.

========
OVERVIEW
========

The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preference proved to be for a new syscall
with an extended stat structure.

A number of requests were gathered for features to be included. The
following have been included:

(1) Make the fields a consistent size on all arches and make them large.

(2) Spare space, request flags and information flags are provided for
future expansion.

(3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
__s64).

(4) Creation time: The SMB protocol carries the creation time, which could
be exported by Samba, which will in turn help CIFS make use of
FS-Cache as that can be used for coherency data (stx_btime).

This is also specified in NFSv4 as a recommended attribute and could
be exported by NFSD [Steve French].

(5) Lightweight stat: Ask for just those details of interest, and allow a
netfs (such as NFS) to approximate anything not of interest, possibly
without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
Dilger] (AT_STATX_DONT_SYNC).

(6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
its cached attributes are up to date [Trond Myklebust]
(AT_STATX_FORCE_SYNC).

And the following have been left out for future extension:

(7) Data version number: Could be used by userspace NFS servers [Aneesh
Kumar].

Can also be used to modify fill_post_wcc() in NFSD which retrieves
i_version directly, but has just called vfs_getattr(). It could get
it from the kstat struct if it used vfs_xgetattr() instead.

(There's disagreement on the exact semantics of a single field, since
not all filesystems do this the same way).

(8) BSD stat compatibility: Including more fields from the BSD stat such
as creation time (st_btime) and inode generation number (st_gen)
[Jeremy Allison, Bernd Schubert].

(9) Inode generation number: Useful for FUSE and userspace NFS servers
[Bernd Schubert].

(This was asked for but later deemed unnecessary with the
open-by-handle capability available and caused disagreement as to
whether it's a security hole or not).

(10) Extra coherency data may be useful in making backups [Andreas Dilger].

(No particular data were offered, but things like last backup
timestamp, the data version number and the DOS archive bit would come
into this category).

(11) Allow the filesystem to indicate what it can/cannot provide: A
filesystem can now say it doesn't support a standard stat feature if
that isn't available, so if, for instance, inode numbers or UIDs don't
exist or are fabricated locally...

(This requires a separate system call - I have an fsinfo() call idea
for this).

(12) Store a 16-byte volume ID in the superblock that can be returned in
struct xstat [Steve French].

(Deferred to fsinfo).

(13) Include granularity fields in the time data to indicate the
granularity of each of the times (NFSv4 time_delta) [Steve French].

(Deferred to fsinfo).

(14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags.
Note that the Linux IOC flags are a mess and filesystems such as Ext4
define flags that aren't in linux/fs.h, so translation in the kernel
may be a necessity (or, possibly, we provide the filesystem type too).

(Some attributes are made available in stx_attributes, but the general
feeling was that the IOC flags were to ext[234]-specific and shouldn't
be exposed through statx this way).

(15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
Michael Kerrisk].

(Deferred, probably to fsinfo. Finding out if there's an ACL or
seclabal might require extra filesystem operations).

(16) Femtosecond-resolution timestamps [Dave Chinner].

(A __reserved field has been left in the statx_timestamp struct for
this - if there proves to be a need).

(17) A set multiple attributes syscall to go with this.

===============
NEW SYSTEM CALL
===============

The new system call is:

int ret = statx(int dfd,
const char *filename,
unsigned int flags,
unsigned int mask,
struct statx *buffer);

The dfd, filename and flags parameters indicate the file to query, in a
similar way to fstatat(). There is no equivalent of lstat() as that can be
emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is
also no equivalent of fstat() as that can be emulated by passing a NULL
filename to statx() with the fd of interest in dfd.

Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):

(1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
respect.

(2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
its attributes with the server - which might require data writeback to
occur to get the timestamps correct.

(3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
network filesystem. The resulting values should be considered
approximate.

mask is a bitmask indicating the fields in struct statx that are of
interest to the caller. The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat(). It should be noted that asking for
more information may entail extra I/O operations.

buffer points to the destination for the data. This must be 256 bytes in
size.

======================
MAIN ATTRIBUTES RECORD
======================

The following structures are defined in which to return the main attribute
set:

struct statx_timestamp {
__s64 tv_sec;
__s32 tv_nsec;
__s32 __reserved;
};

struct statx {
__u32 stx_mask;
__u32 stx_blksize;
__u64 stx_attributes;
__u32 stx_nlink;
__u32 stx_uid;
__u32 stx_gid;
__u16 stx_mode;
__u16 __spare0[1];
__u64 stx_ino;
__u64 stx_size;
__u64 stx_blocks;
__u64 __spare1[1];
struct statx_timestamp stx_atime;
struct statx_timestamp stx_btime;
struct statx_timestamp stx_ctime;
struct statx_timestamp stx_mtime;
__u32 stx_rdev_major;
__u32 stx_rdev_minor;
__u32 stx_dev_major;
__u32 stx_dev_minor;
__u64 __spare2[14];
};

The defined bits in request_mask and stx_mask are:

STATX_TYPE Want/got stx_mode & S_IFMT
STATX_MODE Want/got stx_mode & ~S_IFMT
STATX_NLINK Want/got stx_nlink
STATX_UID Want/got stx_uid
STATX_GID Want/got stx_gid
STATX_ATIME Want/got stx_atime{,_ns}
STATX_MTIME Want/got stx_mtime{,_ns}
STATX_CTIME Want/got stx_ctime{,_ns}
STATX_INO Want/got stx_ino
STATX_SIZE Want/got stx_size
STATX_BLOCKS Want/got stx_blocks
STATX_BASIC_STATS [The stuff in the normal stat struct]
STATX_BTIME Want/got stx_btime{,_ns}
STATX_ALL [All currently available stuff]

stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.

Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution. Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.

The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does. The following
attributes map to FS_*_FL flags and are the same numerical value:

STATX_ATTR_COMPRESSED File is compressed by the fs
STATX_ATTR_IMMUTABLE File is marked immutable
STATX_ATTR_APPEND File is append-only
STATX_ATTR_NODUMP File is not to be dumped
STATX_ATTR_ENCRYPTED File requires key to decrypt in fs

Within the kernel, the supported flags are listed by:

KSTAT_ATTR_FS_IOC_FLAGS

[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]

New flags include:

STATX_ATTR_AUTOMOUNT Object is an automount trigger

These are for the use of GUI tools that might want to mark files specially,
depending on what they are.

Fields in struct statx come in a number of classes:

(0) stx_dev_*, stx_blksize.

These are local system information and are always available.

(1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
stx_size, stx_blocks.

These will be returned whether the caller asks for them or not. The
corresponding bits in stx_mask will be set to indicate whether they
actually have valid values.

If the caller didn't ask for them, then they may be approximated. For
example, NFS won't waste any time updating them from the server,
unless as a byproduct of updating something requested.

If the values don't actually exist for the underlying object (such as
UID or GID on a DOS file), then the bit won't be set in the stx_mask,
even if the caller asked for the value. In such a case, the returned
value will be a fabrication.

Note that there are instances where the type might not be valid, for
instance Windows reparse points.

(2) stx_rdev_*.

This will be set only if stx_mode indicates we're looking at a
blockdev or a chardev, otherwise will be 0.

(3) stx_btime.

Similar to (1), except this will be set to 0 if it doesn't exist.

=======
TESTING
=======

The following test program can be used to test the statx system call:

samples/statx/test-statx.c

Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.

Here's some example output. Firstly, an NFS directory that crosses to
another FSID. Note that the AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.

[root@andromeda ~]# /tmp/test-statx -A /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:26 Inode: 1703937 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)

Secondly, the result of automounting on that directory.

[root@andromeda ~]# /tmp/test-statx /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:27 Inode: 2 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff a528d35e Tue Jan 31 09:46:22 MST 2017 David Howells <dhowells@redhat.com> statx: Add a system call to make enhanced file info available

Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.

The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode. This change is propagated to the vfs_getattr*()
function.

Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.

========
OVERVIEW
========

The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preference proved to be for a new syscall
with an extended stat structure.

A number of requests were gathered for features to be included. The
following have been included:

(1) Make the fields a consistent size on all arches and make them large.

(2) Spare space, request flags and information flags are provided for
future expansion.

(3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
__s64).

(4) Creation time: The SMB protocol carries the creation time, which could
be exported by Samba, which will in turn help CIFS make use of
FS-Cache as that can be used for coherency data (stx_btime).

This is also specified in NFSv4 as a recommended attribute and could
be exported by NFSD [Steve French].

(5) Lightweight stat: Ask for just those details of interest, and allow a
netfs (such as NFS) to approximate anything not of interest, possibly
without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
Dilger] (AT_STATX_DONT_SYNC).

(6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
its cached attributes are up to date [Trond Myklebust]
(AT_STATX_FORCE_SYNC).

And the following have been left out for future extension:

(7) Data version number: Could be used by userspace NFS servers [Aneesh
Kumar].

Can also be used to modify fill_post_wcc() in NFSD which retrieves
i_version directly, but has just called vfs_getattr(). It could get
it from the kstat struct if it used vfs_xgetattr() instead.

(There's disagreement on the exact semantics of a single field, since
not all filesystems do this the same way).

(8) BSD stat compatibility: Including more fields from the BSD stat such
as creation time (st_btime) and inode generation number (st_gen)
[Jeremy Allison, Bernd Schubert].

(9) Inode generation number: Useful for FUSE and userspace NFS servers
[Bernd Schubert].

(This was asked for but later deemed unnecessary with the
open-by-handle capability available and caused disagreement as to
whether it's a security hole or not).

(10) Extra coherency data may be useful in making backups [Andreas Dilger].

(No particular data were offered, but things like last backup
timestamp, the data version number and the DOS archive bit would come
into this category).

(11) Allow the filesystem to indicate what it can/cannot provide: A
filesystem can now say it doesn't support a standard stat feature if
that isn't available, so if, for instance, inode numbers or UIDs don't
exist or are fabricated locally...

(This requires a separate system call - I have an fsinfo() call idea
for this).

(12) Store a 16-byte volume ID in the superblock that can be returned in
struct xstat [Steve French].

(Deferred to fsinfo).

(13) Include granularity fields in the time data to indicate the
granularity of each of the times (NFSv4 time_delta) [Steve French].

(Deferred to fsinfo).

(14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags.
Note that the Linux IOC flags are a mess and filesystems such as Ext4
define flags that aren't in linux/fs.h, so translation in the kernel
may be a necessity (or, possibly, we provide the filesystem type too).

(Some attributes are made available in stx_attributes, but the general
feeling was that the IOC flags were to ext[234]-specific and shouldn't
be exposed through statx this way).

(15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
Michael Kerrisk].

(Deferred, probably to fsinfo. Finding out if there's an ACL or
seclabal might require extra filesystem operations).

(16) Femtosecond-resolution timestamps [Dave Chinner].

(A __reserved field has been left in the statx_timestamp struct for
this - if there proves to be a need).

(17) A set multiple attributes syscall to go with this.

===============
NEW SYSTEM CALL
===============

The new system call is:

int ret = statx(int dfd,
const char *filename,
unsigned int flags,
unsigned int mask,
struct statx *buffer);

The dfd, filename and flags parameters indicate the file to query, in a
similar way to fstatat(). There is no equivalent of lstat() as that can be
emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is
also no equivalent of fstat() as that can be emulated by passing a NULL
filename to statx() with the fd of interest in dfd.

Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):

(1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
respect.

(2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
its attributes with the server - which might require data writeback to
occur to get the timestamps correct.

(3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
network filesystem. The resulting values should be considered
approximate.

mask is a bitmask indicating the fields in struct statx that are of
interest to the caller. The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat(). It should be noted that asking for
more information may entail extra I/O operations.

buffer points to the destination for the data. This must be 256 bytes in
size.

======================
MAIN ATTRIBUTES RECORD
======================

The following structures are defined in which to return the main attribute
set:

struct statx_timestamp {
__s64 tv_sec;
__s32 tv_nsec;
__s32 __reserved;
};

struct statx {
__u32 stx_mask;
__u32 stx_blksize;
__u64 stx_attributes;
__u32 stx_nlink;
__u32 stx_uid;
__u32 stx_gid;
__u16 stx_mode;
__u16 __spare0[1];
__u64 stx_ino;
__u64 stx_size;
__u64 stx_blocks;
__u64 __spare1[1];
struct statx_timestamp stx_atime;
struct statx_timestamp stx_btime;
struct statx_timestamp stx_ctime;
struct statx_timestamp stx_mtime;
__u32 stx_rdev_major;
__u32 stx_rdev_minor;
__u32 stx_dev_major;
__u32 stx_dev_minor;
__u64 __spare2[14];
};

The defined bits in request_mask and stx_mask are:

STATX_TYPE Want/got stx_mode & S_IFMT
STATX_MODE Want/got stx_mode & ~S_IFMT
STATX_NLINK Want/got stx_nlink
STATX_UID Want/got stx_uid
STATX_GID Want/got stx_gid
STATX_ATIME Want/got stx_atime{,_ns}
STATX_MTIME Want/got stx_mtime{,_ns}
STATX_CTIME Want/got stx_ctime{,_ns}
STATX_INO Want/got stx_ino
STATX_SIZE Want/got stx_size
STATX_BLOCKS Want/got stx_blocks
STATX_BASIC_STATS [The stuff in the normal stat struct]
STATX_BTIME Want/got stx_btime{,_ns}
STATX_ALL [All currently available stuff]

stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.

Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution. Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.

The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does. The following
attributes map to FS_*_FL flags and are the same numerical value:

STATX_ATTR_COMPRESSED File is compressed by the fs
STATX_ATTR_IMMUTABLE File is marked immutable
STATX_ATTR_APPEND File is append-only
STATX_ATTR_NODUMP File is not to be dumped
STATX_ATTR_ENCRYPTED File requires key to decrypt in fs

Within the kernel, the supported flags are listed by:

KSTAT_ATTR_FS_IOC_FLAGS

[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]

New flags include:

STATX_ATTR_AUTOMOUNT Object is an automount trigger

These are for the use of GUI tools that might want to mark files specially,
depending on what they are.

Fields in struct statx come in a number of classes:

(0) stx_dev_*, stx_blksize.

These are local system information and are always available.

(1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
stx_size, stx_blocks.

These will be returned whether the caller asks for them or not. The
corresponding bits in stx_mask will be set to indicate whether they
actually have valid values.

If the caller didn't ask for them, then they may be approximated. For
example, NFS won't waste any time updating them from the server,
unless as a byproduct of updating something requested.

If the values don't actually exist for the underlying object (such as
UID or GID on a DOS file), then the bit won't be set in the stx_mask,
even if the caller asked for the value. In such a case, the returned
value will be a fabrication.

Note that there are instances where the type might not be valid, for
instance Windows reparse points.

(2) stx_rdev_*.

This will be set only if stx_mode indicates we're looking at a
blockdev or a chardev, otherwise will be 0.

(3) stx_btime.

Similar to (1), except this will be set to 0 if it doesn't exist.

=======
TESTING
=======

The following test program can be used to test the statx system call:

samples/statx/test-statx.c

Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.

Here's some example output. Firstly, an NFS directory that crosses to
another FSID. Note that the AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.

[root@andromeda ~]# /tmp/test-statx -A /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:26 Inode: 1703937 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)

Secondly, the result of automounting on that directory.

[root@andromeda ~]# /tmp/test-statx /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:27 Inode: 2 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff a528d35e Tue Jan 31 09:46:22 MST 2017 David Howells <dhowells@redhat.com> statx: Add a system call to make enhanced file info available

Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.

The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode. This change is propagated to the vfs_getattr*()
function.

Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.

========
OVERVIEW
========

The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preference proved to be for a new syscall
with an extended stat structure.

A number of requests were gathered for features to be included. The
following have been included:

(1) Make the fields a consistent size on all arches and make them large.

(2) Spare space, request flags and information flags are provided for
future expansion.

(3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
__s64).

(4) Creation time: The SMB protocol carries the creation time, which could
be exported by Samba, which will in turn help CIFS make use of
FS-Cache as that can be used for coherency data (stx_btime).

This is also specified in NFSv4 as a recommended attribute and could
be exported by NFSD [Steve French].

(5) Lightweight stat: Ask for just those details of interest, and allow a
netfs (such as NFS) to approximate anything not of interest, possibly
without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
Dilger] (AT_STATX_DONT_SYNC).

(6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
its cached attributes are up to date [Trond Myklebust]
(AT_STATX_FORCE_SYNC).

And the following have been left out for future extension:

(7) Data version number: Could be used by userspace NFS servers [Aneesh
Kumar].

Can also be used to modify fill_post_wcc() in NFSD which retrieves
i_version directly, but has just called vfs_getattr(). It could get
it from the kstat struct if it used vfs_xgetattr() instead.

(There's disagreement on the exact semantics of a single field, since
not all filesystems do this the same way).

(8) BSD stat compatibility: Including more fields from the BSD stat such
as creation time (st_btime) and inode generation number (st_gen)
[Jeremy Allison, Bernd Schubert].

(9) Inode generation number: Useful for FUSE and userspace NFS servers
[Bernd Schubert].

(This was asked for but later deemed unnecessary with the
open-by-handle capability available and caused disagreement as to
whether it's a security hole or not).

(10) Extra coherency data may be useful in making backups [Andreas Dilger].

(No particular data were offered, but things like last backup
timestamp, the data version number and the DOS archive bit would come
into this category).

(11) Allow the filesystem to indicate what it can/cannot provide: A
filesystem can now say it doesn't support a standard stat feature if
that isn't available, so if, for instance, inode numbers or UIDs don't
exist or are fabricated locally...

(This requires a separate system call - I have an fsinfo() call idea
for this).

(12) Store a 16-byte volume ID in the superblock that can be returned in
struct xstat [Steve French].

(Deferred to fsinfo).

(13) Include granularity fields in the time data to indicate the
granularity of each of the times (NFSv4 time_delta) [Steve French].

(Deferred to fsinfo).

(14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags.
Note that the Linux IOC flags are a mess and filesystems such as Ext4
define flags that aren't in linux/fs.h, so translation in the kernel
may be a necessity (or, possibly, we provide the filesystem type too).

(Some attributes are made available in stx_attributes, but the general
feeling was that the IOC flags were to ext[234]-specific and shouldn't
be exposed through statx this way).

(15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
Michael Kerrisk].

(Deferred, probably to fsinfo. Finding out if there's an ACL or
seclabal might require extra filesystem operations).

(16) Femtosecond-resolution timestamps [Dave Chinner].

(A __reserved field has been left in the statx_timestamp struct for
this - if there proves to be a need).

(17) A set multiple attributes syscall to go with this.

===============
NEW SYSTEM CALL
===============

The new system call is:

int ret = statx(int dfd,
const char *filename,
unsigned int flags,
unsigned int mask,
struct statx *buffer);

The dfd, filename and flags parameters indicate the file to query, in a
similar way to fstatat(). There is no equivalent of lstat() as that can be
emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is
also no equivalent of fstat() as that can be emulated by passing a NULL
filename to statx() with the fd of interest in dfd.

Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):

(1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
respect.

(2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
its attributes with the server - which might require data writeback to
occur to get the timestamps correct.

(3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
network filesystem. The resulting values should be considered
approximate.

mask is a bitmask indicating the fields in struct statx that are of
interest to the caller. The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat(). It should be noted that asking for
more information may entail extra I/O operations.

buffer points to the destination for the data. This must be 256 bytes in
size.

======================
MAIN ATTRIBUTES RECORD
======================

The following structures are defined in which to return the main attribute
set:

struct statx_timestamp {
__s64 tv_sec;
__s32 tv_nsec;
__s32 __reserved;
};

struct statx {
__u32 stx_mask;
__u32 stx_blksize;
__u64 stx_attributes;
__u32 stx_nlink;
__u32 stx_uid;
__u32 stx_gid;
__u16 stx_mode;
__u16 __spare0[1];
__u64 stx_ino;
__u64 stx_size;
__u64 stx_blocks;
__u64 __spare1[1];
struct statx_timestamp stx_atime;
struct statx_timestamp stx_btime;
struct statx_timestamp stx_ctime;
struct statx_timestamp stx_mtime;
__u32 stx_rdev_major;
__u32 stx_rdev_minor;
__u32 stx_dev_major;
__u32 stx_dev_minor;
__u64 __spare2[14];
};

The defined bits in request_mask and stx_mask are:

STATX_TYPE Want/got stx_mode & S_IFMT
STATX_MODE Want/got stx_mode & ~S_IFMT
STATX_NLINK Want/got stx_nlink
STATX_UID Want/got stx_uid
STATX_GID Want/got stx_gid
STATX_ATIME Want/got stx_atime{,_ns}
STATX_MTIME Want/got stx_mtime{,_ns}
STATX_CTIME Want/got stx_ctime{,_ns}
STATX_INO Want/got stx_ino
STATX_SIZE Want/got stx_size
STATX_BLOCKS Want/got stx_blocks
STATX_BASIC_STATS [The stuff in the normal stat struct]
STATX_BTIME Want/got stx_btime{,_ns}
STATX_ALL [All currently available stuff]

stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.

Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution. Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.

The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does. The following
attributes map to FS_*_FL flags and are the same numerical value:

STATX_ATTR_COMPRESSED File is compressed by the fs
STATX_ATTR_IMMUTABLE File is marked immutable
STATX_ATTR_APPEND File is append-only
STATX_ATTR_NODUMP File is not to be dumped
STATX_ATTR_ENCRYPTED File requires key to decrypt in fs

Within the kernel, the supported flags are listed by:

KSTAT_ATTR_FS_IOC_FLAGS

[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]

New flags include:

STATX_ATTR_AUTOMOUNT Object is an automount trigger

These are for the use of GUI tools that might want to mark files specially,
depending on what they are.

Fields in struct statx come in a number of classes:

(0) stx_dev_*, stx_blksize.

These are local system information and are always available.

(1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
stx_size, stx_blocks.

These will be returned whether the caller asks for them or not. The
corresponding bits in stx_mask will be set to indicate whether they
actually have valid values.

If the caller didn't ask for them, then they may be approximated. For
example, NFS won't waste any time updating them from the server,
unless as a byproduct of updating something requested.

If the values don't actually exist for the underlying object (such as
UID or GID on a DOS file), then the bit won't be set in the stx_mask,
even if the caller asked for the value. In such a case, the returned
value will be a fabrication.

Note that there are instances where the type might not be valid, for
instance Windows reparse points.

(2) stx_rdev_*.

This will be set only if stx_mode indicates we're looking at a
blockdev or a chardev, otherwise will be 0.

(3) stx_btime.

Similar to (1), except this will be set to 0 if it doesn't exist.

=======
TESTING
=======

The following test program can be used to test the statx system call:

samples/statx/test-statx.c

Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.

Here's some example output. Firstly, an NFS directory that crosses to
another FSID. Note that the AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.

[root@andromeda ~]# /tmp/test-statx -A /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:26 Inode: 1703937 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)

Secondly, the result of automounting on that directory.

[root@andromeda ~]# /tmp/test-statx /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:27 Inode: 2 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff a528d35e Tue Jan 31 09:46:22 MST 2017 David Howells <dhowells@redhat.com> statx: Add a system call to make enhanced file info available

Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.

The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode. This change is propagated to the vfs_getattr*()
function.

Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.

========
OVERVIEW
========

The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preference proved to be for a new syscall
with an extended stat structure.

A number of requests were gathered for features to be included. The
following have been included:

(1) Make the fields a consistent size on all arches and make them large.

(2) Spare space, request flags and information flags are provided for
future expansion.

(3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
__s64).

(4) Creation time: The SMB protocol carries the creation time, which could
be exported by Samba, which will in turn help CIFS make use of
FS-Cache as that can be used for coherency data (stx_btime).

This is also specified in NFSv4 as a recommended attribute and could
be exported by NFSD [Steve French].

(5) Lightweight stat: Ask for just those details of interest, and allow a
netfs (such as NFS) to approximate anything not of interest, possibly
without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
Dilger] (AT_STATX_DONT_SYNC).

(6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
its cached attributes are up to date [Trond Myklebust]
(AT_STATX_FORCE_SYNC).

And the following have been left out for future extension:

(7) Data version number: Could be used by userspace NFS servers [Aneesh
Kumar].

Can also be used to modify fill_post_wcc() in NFSD which retrieves
i_version directly, but has just called vfs_getattr(). It could get
it from the kstat struct if it used vfs_xgetattr() instead.

(There's disagreement on the exact semantics of a single field, since
not all filesystems do this the same way).

(8) BSD stat compatibility: Including more fields from the BSD stat such
as creation time (st_btime) and inode generation number (st_gen)
[Jeremy Allison, Bernd Schubert].

(9) Inode generation number: Useful for FUSE and userspace NFS servers
[Bernd Schubert].

(This was asked for but later deemed unnecessary with the
open-by-handle capability available and caused disagreement as to
whether it's a security hole or not).

(10) Extra coherency data may be useful in making backups [Andreas Dilger].

(No particular data were offered, but things like last backup
timestamp, the data version number and the DOS archive bit would come
into this category).

(11) Allow the filesystem to indicate what it can/cannot provide: A
filesystem can now say it doesn't support a standard stat feature if
that isn't available, so if, for instance, inode numbers or UIDs don't
exist or are fabricated locally...

(This requires a separate system call - I have an fsinfo() call idea
for this).

(12) Store a 16-byte volume ID in the superblock that can be returned in
struct xstat [Steve French].

(Deferred to fsinfo).

(13) Include granularity fields in the time data to indicate the
granularity of each of the times (NFSv4 time_delta) [Steve French].

(Deferred to fsinfo).

(14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags.
Note that the Linux IOC flags are a mess and filesystems such as Ext4
define flags that aren't in linux/fs.h, so translation in the kernel
may be a necessity (or, possibly, we provide the filesystem type too).

(Some attributes are made available in stx_attributes, but the general
feeling was that the IOC flags were to ext[234]-specific and shouldn't
be exposed through statx this way).

(15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
Michael Kerrisk].

(Deferred, probably to fsinfo. Finding out if there's an ACL or
seclabal might require extra filesystem operations).

(16) Femtosecond-resolution timestamps [Dave Chinner].

(A __reserved field has been left in the statx_timestamp struct for
this - if there proves to be a need).

(17) A set multiple attributes syscall to go with this.

===============
NEW SYSTEM CALL
===============

The new system call is:

int ret = statx(int dfd,
const char *filename,
unsigned int flags,
unsigned int mask,
struct statx *buffer);

The dfd, filename and flags parameters indicate the file to query, in a
similar way to fstatat(). There is no equivalent of lstat() as that can be
emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is
also no equivalent of fstat() as that can be emulated by passing a NULL
filename to statx() with the fd of interest in dfd.

Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):

(1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
respect.

(2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
its attributes with the server - which might require data writeback to
occur to get the timestamps correct.

(3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
network filesystem. The resulting values should be considered
approximate.

mask is a bitmask indicating the fields in struct statx that are of
interest to the caller. The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat(). It should be noted that asking for
more information may entail extra I/O operations.

buffer points to the destination for the data. This must be 256 bytes in
size.

======================
MAIN ATTRIBUTES RECORD
======================

The following structures are defined in which to return the main attribute
set:

struct statx_timestamp {
__s64 tv_sec;
__s32 tv_nsec;
__s32 __reserved;
};

struct statx {
__u32 stx_mask;
__u32 stx_blksize;
__u64 stx_attributes;
__u32 stx_nlink;
__u32 stx_uid;
__u32 stx_gid;
__u16 stx_mode;
__u16 __spare0[1];
__u64 stx_ino;
__u64 stx_size;
__u64 stx_blocks;
__u64 __spare1[1];
struct statx_timestamp stx_atime;
struct statx_timestamp stx_btime;
struct statx_timestamp stx_ctime;
struct statx_timestamp stx_mtime;
__u32 stx_rdev_major;
__u32 stx_rdev_minor;
__u32 stx_dev_major;
__u32 stx_dev_minor;
__u64 __spare2[14];
};

The defined bits in request_mask and stx_mask are:

STATX_TYPE Want/got stx_mode & S_IFMT
STATX_MODE Want/got stx_mode & ~S_IFMT
STATX_NLINK Want/got stx_nlink
STATX_UID Want/got stx_uid
STATX_GID Want/got stx_gid
STATX_ATIME Want/got stx_atime{,_ns}
STATX_MTIME Want/got stx_mtime{,_ns}
STATX_CTIME Want/got stx_ctime{,_ns}
STATX_INO Want/got stx_ino
STATX_SIZE Want/got stx_size
STATX_BLOCKS Want/got stx_blocks
STATX_BASIC_STATS [The stuff in the normal stat struct]
STATX_BTIME Want/got stx_btime{,_ns}
STATX_ALL [All currently available stuff]

stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.

Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution. Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.

The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does. The following
attributes map to FS_*_FL flags and are the same numerical value:

STATX_ATTR_COMPRESSED File is compressed by the fs
STATX_ATTR_IMMUTABLE File is marked immutable
STATX_ATTR_APPEND File is append-only
STATX_ATTR_NODUMP File is not to be dumped
STATX_ATTR_ENCRYPTED File requires key to decrypt in fs

Within the kernel, the supported flags are listed by:

KSTAT_ATTR_FS_IOC_FLAGS

[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]

New flags include:

STATX_ATTR_AUTOMOUNT Object is an automount trigger

These are for the use of GUI tools that might want to mark files specially,
depending on what they are.

Fields in struct statx come in a number of classes:

(0) stx_dev_*, stx_blksize.

These are local system information and are always available.

(1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
stx_size, stx_blocks.

These will be returned whether the caller asks for them or not. The
corresponding bits in stx_mask will be set to indicate whether they
actually have valid values.

If the caller didn't ask for them, then they may be approximated. For
example, NFS won't waste any time updating them from the server,
unless as a byproduct of updating something requested.

If the values don't actually exist for the underlying object (such as
UID or GID on a DOS file), then the bit won't be set in the stx_mask,
even if the caller asked for the value. In such a case, the returned
value will be a fabrication.

Note that there are instances where the type might not be valid, for
instance Windows reparse points.

(2) stx_rdev_*.

This will be set only if stx_mode indicates we're looking at a
blockdev or a chardev, otherwise will be 0.

(3) stx_btime.

Similar to (1), except this will be set to 0 if it doesn't exist.

=======
TESTING
=======

The following test program can be used to test the statx system call:

samples/statx/test-statx.c

Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.

Here's some example output. Firstly, an NFS directory that crosses to
another FSID. Note that the AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.

[root@andromeda ~]# /tmp/test-statx -A /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:26 Inode: 1703937 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)

Secondly, the result of automounting on that directory.

[root@andromeda ~]# /tmp/test-statx /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:27 Inode: 2 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff 2b0143b5 Tue Mar 17 16:25:59 MDT 2015 David Howells <dhowells@redhat.com> VFS: normal filesystems (and lustre): d_inode() annotations

that's the bulk of filesystem drivers dealing with inodes of their own

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff e36cb0b8 Wed Jan 28 17:02:35 MST 2015 David Howells <dhowells@redhat.com> VFS: (Scripted) Convert S_ISLNK/DIR/REG(dentry->d_inode) to d_is_*(dentry)

Convert the following where appropriate:

(1) S_ISLNK(dentry->d_inode) to d_is_symlink(dentry).

(2) S_ISREG(dentry->d_inode) to d_is_reg(dentry).

(3) S_ISDIR(dentry->d_inode) to d_is_dir(dentry). This is actually more
complicated than it appears as some calls should be converted to
d_can_lookup() instead. The difference is whether the directory in
question is a real dir with a ->lookup op or whether it's a fake dir with
a ->d_automount op.

In some circumstances, we can subsume checks for dentry->d_inode not being
NULL into this, provided we the code isn't in a filesystem that expects
d_inode to be NULL if the dirent really *is* negative (ie. if we're going to
use d_inode() rather than d_backing_inode() to get the inode pointer).

Note that the dentry type field may be set to something other than
DCACHE_MISS_TYPE when d_inode is NULL in the case of unionmount, where the VFS
manages the fall-through from a negative dentry to a lower layer. In such a
case, the dentry type of the negative union dentry is set to the same as the
type of the lower dentry.

However, if you know d_inode is not NULL at the call site, then you can use
the d_is_xxx() functions even in a filesystem.

There is one further complication: a 0,0 chardev dentry may be labelled
DCACHE_WHITEOUT_TYPE rather than DCACHE_SPECIAL_TYPE. Strictly, this was
intended for special directory entry types that don't have attached inodes.

The following perl+coccinelle script was used:

use strict;

my @callers;
open($fd, 'git grep -l \'S_IS[A-Z].*->d_inode\' |') ||
die "Can't grep for S_ISDIR and co. callers";
@callers = <$fd>;
close($fd);
unless (@callers) {
print "No matches\n";
exit(0);
}

my @cocci = (
'@@',
'expression E;',
'@@',
'',
'- S_ISLNK(E->d_inode->i_mode)',
'+ d_is_symlink(E)',
'',
'@@',
'expression E;',
'@@',
'',
'- S_ISDIR(E->d_inode->i_mode)',
'+ d_is_dir(E)',
'',
'@@',
'expression E;',
'@@',
'',
'- S_ISREG(E->d_inode->i_mode)',
'+ d_is_reg(E)' );

my $coccifile = "tmp.sp.cocci";
open($fd, ">$coccifile") || die $coccifile;
print($fd "$_\n") || die $coccifile foreach (@cocci);
close($fd);

foreach my $file (@callers) {
chomp $file;
print "Processing ", $file, "\n";
system("spatch", "--sp-file", $coccifile, $file, "--in-place", "--no-show-diff") == 0 ||
die "spatch failed";
}

[AV: overlayfs parts skipped]

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
/linux-master/fs/exfat/
H A Dfile.cdiff 0d72b928 Mon Aug 07 13:38:33 MDT 2023 Jeff Layton <jlayton@kernel.org> fs: pass the request_mask to generic_fillattr

generic_fillattr just fills in the entire stat struct indiscriminately
today, copying data from the inode. There is at least one attribute
(STATX_CHANGE_COOKIE) that can have side effects when it is reported,
and we're looking at adding more with the addition of multigrain
timestamps.

Add a request_mask argument to generic_fillattr and have most callers
just pass in the value that is passed to getattr. Have other callers
(e.g. ksmbd) just pass in STATX_BASIC_STATS. Also move the setting of
STATX_CHANGE_COOKIE into generic_fillattr.

Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: "Paulo Alcantara (SUSE)" <pc@manguebit.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Message-Id: <20230807-mgctime-v7-2-d1dec143a704@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff 2cb1e089 Mon May 22 07:50:15 MDT 2023 David Howells <dhowells@redhat.com> splice: Use filemap_splice_read() instead of generic_file_splice_read()

Replace pointers to generic_file_splice_read() with calls to
filemap_splice_read().

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: David Hildenbrand <david@redhat.com>
cc: John Hubbard <jhubbard@nvidia.com>
cc: linux-mm@kvack.org
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20230522135018.2742245-29-dhowells@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 81df1ad4 Mon Apr 20 20:13:10 MDT 2020 Eric Sandeen <sandeen@sandeen.net> exfat: truncate atimes to 2s granularity

The timestamp for access_time has double seconds granularity(There is no
10msIncrement field for access_time unlike create/modify_time).
exfat's atimes are restricted to only 2s granularity so after
we set an atime, round it down to the nearest 2s and set the
sub-second component of the timestamp to 0.

Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
diff 81df1ad4 Mon Apr 20 20:13:10 MDT 2020 Eric Sandeen <sandeen@sandeen.net> exfat: truncate atimes to 2s granularity

The timestamp for access_time has double seconds granularity(There is no
10msIncrement field for access_time unlike create/modify_time).
exfat's atimes are restricted to only 2s granularity so after
we set an atime, round it down to the nearest 2s and set the
sub-second component of the timestamp to 0.

Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
diff 81df1ad4 Mon Apr 20 20:13:10 MDT 2020 Eric Sandeen <sandeen@sandeen.net> exfat: truncate atimes to 2s granularity

The timestamp for access_time has double seconds granularity(There is no
10msIncrement field for access_time unlike create/modify_time).
exfat's atimes are restricted to only 2s granularity so after
we set an atime, round it down to the nearest 2s and set the
sub-second component of the timestamp to 0.

Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
/linux-master/fs/ext2/
H A Dinode.cdiff 2ebc736c Thu Aug 17 13:59:25 MDT 2023 Georg Ottinger <g.ottinger@gmx.at> ext2: improve consistency of ext2_fsblk_t datatype usage

The ext2 block allocation/deallocation functions and their respective
calls use a mixture of unsigned long and ext2_fsblk_t datatypes to
index the desired ext2 block. This commit replaces occurrences of
unsigned long with ext2_fsblk_t, covering the functions
ext2_new_block(), ext2_new_blocks(), ext2_free_blocks(),
ext2_free_data() and ext2_free_branches(). This commit is rather
conservative, and only replaces unsigned long with ext2_fsblk_t if
the variable is used to index a specific ext2 block.

Signed-off-by: Georg Ottinger <g.ottinger@gmx.at>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20230817195925.10268-1-g.ottinger@gmx.at>
diff 0d72b928 Mon Aug 07 13:38:33 MDT 2023 Jeff Layton <jlayton@kernel.org> fs: pass the request_mask to generic_fillattr

generic_fillattr just fills in the entire stat struct indiscriminately
today, copying data from the inode. There is at least one attribute
(STATX_CHANGE_COOKIE) that can have side effects when it is reported,
and we're looking at adding more with the addition of multigrain
timestamps.

Add a request_mask argument to generic_fillattr and have most callers
just pass in the value that is passed to getattr. Have other callers
(e.g. ksmbd) just pass in STATX_BASIC_STATS. Also move the setting of
STATX_CHANGE_COOKIE into generic_fillattr.

Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: "Paulo Alcantara (SUSE)" <pc@manguebit.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Message-Id: <20230807-mgctime-v7-2-d1dec143a704@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff fcced95b Fri Apr 21 03:46:11 MDT 2023 Ritesh Harjani (IBM) <ritesh.list@gmail.com> ext2/dax: Fix ext2_setsize when len is page aligned

PAGE_ALIGN(x) macro gives the next highest value which is multiple of
pagesize. But if x is already page aligned then it simply returns x.
So, if x passed is 0 in dax_zero_range() function, that means the
length gets passed as 0 to ->iomap_begin().

In ext2 it then calls ext2_get_blocks -> max_blocks as 0 and hits bug_on
here in ext2_get_blocks().
BUG_ON(maxblocks == 0);

Instead we should be calling dax_truncate_page() here which takes
care of it. i.e. it only calls dax_zero_range if the offset is not
page/block aligned.

This can be easily triggered with following on fsdax mounted pmem
device.

dd if=/dev/zero of=file count=1 bs=512
truncate -s 0 file

[79.525838] EXT2-fs (pmem0): DAX enabled. Warning: EXPERIMENTAL, use at your own risk
[79.529376] ext2 filesystem being mounted at /mnt1/test supports timestamps until 2038 (0x7fffffff)
[93.793207] ------------[ cut here ]------------
[93.795102] kernel BUG at fs/ext2/inode.c:637!
[93.796904] invalid opcode: 0000 [#1] PREEMPT SMP PTI
[93.798659] CPU: 0 PID: 1192 Comm: truncate Not tainted 6.3.0-rc2-xfstests-00056-g131086faa369 #139
[93.806459] RIP: 0010:ext2_get_blocks.constprop.0+0x524/0x610
<...>
[93.835298] Call Trace:
[93.836253] <TASK>
[93.837103] ? lock_acquire+0xf8/0x110
[93.838479] ? d_lookup+0x69/0xd0
[93.839779] ext2_iomap_begin+0xa7/0x1c0
[93.841154] iomap_iter+0xc7/0x150
[93.842425] dax_zero_range+0x6e/0xa0
[93.843813] ext2_setsize+0x176/0x1b0
[93.845164] ext2_setattr+0x151/0x200
[93.846467] notify_change+0x341/0x4e0
[93.847805] ? lock_acquire+0xf8/0x110
[93.849143] ? do_truncate+0x74/0xe0
[93.850452] ? do_truncate+0x84/0xe0
[93.851739] do_truncate+0x84/0xe0
[93.852974] do_sys_ftruncate+0x2b4/0x2f0
[93.854404] do_syscall_64+0x3f/0x90
[93.855789] entry_SYSCALL_64_after_hwframe+0x72/0xdc

CC: stable@vger.kernel.org
Fixes: 2aa3048e03d3 ("iomap: switch iomap_zero_range to use iomap_iter")
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <046a58317f29d9603d1068b2bbae47c2332c17ae.1682069716.git.ritesh.list@gmail.com>
diff 2aab03b8 Sun Jun 05 06:55:09 MDT 2022 Xiang wangx <wangxiang@cdjrlc.com> fs: Fix syntax errors in comments

Delete the redundant word 'not'.

Link: https://lore.kernel.org/r/20220605125509.14837-1-wangxiang@cdjrlc.com
Signed-off-by: Xiang wangx <wangxiang@cdjrlc.com>
Signed-off-by: Jan Kara <jack@suse.cz>
diff 9583db23 Tue Jul 20 07:33:38 MDT 2021 Christoph Hellwig <hch@lst.de> ext2: make ext2_iomap_ops available unconditionally

ext2_iomap_ops will be used for the FIEMAP support going forward,
so make it available unconditionally.

Link: https://lore.kernel.org/r/20210720133341.405438-2-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 5aa1437d Thu May 17 15:18:30 MDT 2018 Al Viro <viro@zeniv.linux.org.uk> ext2: fix a block leak

open file, unlink it, then use ioctl(2) to make it immutable or
append only. Now close it and watch the blocks *not* freed...

Immutable/append-only checks belong in ->setattr().
Note: the bug is old and backport to anything prior to 737f2e93b972
("ext2: convert to use the new truncate convention") will need
these checks lifted into ext2_setattr().

Cc: stable@kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff b2441318 Wed Nov 01 08:07:57 MDT 2017 Greg Kroah-Hartman <gregkh@linuxfoundation.org> License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff b2441318 Wed Nov 01 08:07:57 MDT 2017 Greg Kroah-Hartman <gregkh@linuxfoundation.org> License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
/linux-master/fs/ext4/
H A Dinode.cdiff 3fcc2b88 Fri Jan 26 18:58:00 MST 2024 Zhang Yi <yi.zhang@huawei.com> ext4: refactor ext4_da_map_blocks()

Refactor and cleanup ext4_da_map_blocks(), reduce some unnecessary
parameters and branches, no logic changes.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20240127015825.1608160-2-yi.zhang@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff 2ffd2a6a Fri Jan 05 02:21:01 MST 2024 Kemeng Shi <shikemeng@huaweicloud.com> ext4: remove unnecessary parameter "needed" in ext4_discard_preallocations

The "needed" controls the number of ext4_prealloc_space to discard in
ext4_discard_preallocations. Function ext4_discard_preallocations is
supposed to discard all non-used preallocated blocks when "needed"
is 0 and now ext4_discard_preallocations is always called with "needed"
= 0. Remove unnecessary parameter "needed" and remove all non-used
preallocated spaces in ext4_discard_preallocations to simplify the
code.

Note: If count of non-used preallocated spaces could be more than
UINT_MAX, there was a memory leak as some non-used preallocated
spaces are left ununsed and this commit will fix it. Otherwise,
there is no behavior change.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20240105092102.496631-9-shikemeng@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff 2cd8bdb5 Mon Sep 18 04:45:50 MDT 2023 Ojaswin Mujoo <ojaswin@linux.ibm.com> ext4: mark buffer new if it is unwritten to avoid stale data exposure

** Short Version **

In ext4 with dioread_nolock, we could have a scenario where the bh returned by
get_blocks (ext4_get_block_unwritten()) in __block_write_begin_int() has
UNWRITTEN and MAPPED flag set. Since such a bh does not have NEW flag set we
never zero out the range of bh that is not under write, causing whatever stale
data is present in the folio at that time to be written out to disk. To fix this
mark the buffer as new, in case it is unwritten, in ext4_get_block_unwritten().

** Long Version **

The issue mentioned above was resulting in two different bugs:

1. On block size < page size case in ext4, generic/269 was reliably
failing with dioread_nolock. The state of the write was as follows:

* The write was extending i_size.
* The last block of the file was fallocated and had an unwritten extent
* We were near ENOSPC and hence we were switching to non-delayed alloc
allocation.

In this case, the back trace that triggers the bug is as follows:

ext4_da_write_begin()
/* switch to nodelalloc due to low space */
ext4_write_begin()
ext4_should_dioread_nolock() // true since mount flags still have delalloc
__block_write_begin(..., ext4_get_block_unwritten)
__block_write_begin_int()
for(each buffer head in page) {
/* first iteration, this is bh1 which contains i_size */
if (!buffer_mapped)
get_block() /* returns bh with only UNWRITTEN and MAPPED */
/* second iteration, bh2 */
if (!buffer_mapped)
get_block() /* we fail here, could be ENOSPC */
}
if (err)
/*
* this would zero out all new buffers and mark them uptodate.
* Since bh1 was never marked new, we skip it here which causes
* the bug later.
*/
folio_zero_new_buffers();
/* ext4_wrte_begin() error handling */
ext4_truncate_failed_write()
ext4_truncate()
ext4_block_truncate_page()
__ext4_block_zero_page_range()
if(!buffer_uptodate())
ext4_read_bh_lock()
ext4_read_bh() -> ... ext4_submit_bh_wbc()
BUG_ON(buffer_unwritten(bh)); /* !!! */

2. The second issue is stale data exposure with page size >= blocksize
with dioread_nolock. The conditions needed for it to happen are same as
the previous issue ie dioread_nolock around ENOSPC condition. The issue
is also similar where in __block_write_begin_int() when we call
ext4_get_block_unwritten() on the buffer_head and the underlying extent
is unwritten, we get an unwritten and mapped buffer head. Since it is
not new, we never zero out the partial range which is not under write,
thus writing stale data to disk. This can be easily observed with the
following reproducer:

fallocate -l 4k testfile
xfs_io -c "pwrite 2k 2k" testfile
# hexdump output will have stale data in from byte 0 to 2k in testfile
hexdump -C testfile

NOTE: To trigger this, we need dioread_nolock enabled and write happening via
ext4_write_begin(), which is usually used when we have -o nodealloc. Since
dioread_nolock is disabled with nodelalloc, the only alternate way to call
ext4_write_begin() is to ensure that delayed alloc switches to nodelalloc ie
ext4_da_write_begin() calls ext4_write_begin(). This will usually happen when
ext4 is almost full like the way generic/269 was triggering it in Issue 1 above.
This might make the issue harder to hit. Hence, for reliable replication, I used
the below patch to temporarily allow dioread_nolock with nodelalloc and then
mount the disk with -o nodealloc,dioread_nolock. With this you can hit the stale
data issue 100% of times:

@@ -508,8 +508,8 @@ static inline int ext4_should_dioread_nolock(struct inode *inode)
if (ext4_should_journal_data(inode))
return 0;
/* temporary fix to prevent generic/422 test failures */
- if (!test_opt(inode->i_sb, DELALLOC))
- return 0;
+ // if (!test_opt(inode->i_sb, DELALLOC))
+ // return 0;
return 1;
}

After applying this patch to mark buffer as NEW, both the above issues are
fixed.

Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Cc: stable@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/d0ed09d70a9733fbb5349c5c7b125caac186ecdf.1695033645.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff 2cd8bdb5 Mon Sep 18 04:45:50 MDT 2023 Ojaswin Mujoo <ojaswin@linux.ibm.com> ext4: mark buffer new if it is unwritten to avoid stale data exposure

** Short Version **

In ext4 with dioread_nolock, we could have a scenario where the bh returned by
get_blocks (ext4_get_block_unwritten()) in __block_write_begin_int() has
UNWRITTEN and MAPPED flag set. Since such a bh does not have NEW flag set we
never zero out the range of bh that is not under write, causing whatever stale
data is present in the folio at that time to be written out to disk. To fix this
mark the buffer as new, in case it is unwritten, in ext4_get_block_unwritten().

** Long Version **

The issue mentioned above was resulting in two different bugs:

1. On block size < page size case in ext4, generic/269 was reliably
failing with dioread_nolock. The state of the write was as follows:

* The write was extending i_size.
* The last block of the file was fallocated and had an unwritten extent
* We were near ENOSPC and hence we were switching to non-delayed alloc
allocation.

In this case, the back trace that triggers the bug is as follows:

ext4_da_write_begin()
/* switch to nodelalloc due to low space */
ext4_write_begin()
ext4_should_dioread_nolock() // true since mount flags still have delalloc
__block_write_begin(..., ext4_get_block_unwritten)
__block_write_begin_int()
for(each buffer head in page) {
/* first iteration, this is bh1 which contains i_size */
if (!buffer_mapped)
get_block() /* returns bh with only UNWRITTEN and MAPPED */
/* second iteration, bh2 */
if (!buffer_mapped)
get_block() /* we fail here, could be ENOSPC */
}
if (err)
/*
* this would zero out all new buffers and mark them uptodate.
* Since bh1 was never marked new, we skip it here which causes
* the bug later.
*/
folio_zero_new_buffers();
/* ext4_wrte_begin() error handling */
ext4_truncate_failed_write()
ext4_truncate()
ext4_block_truncate_page()
__ext4_block_zero_page_range()
if(!buffer_uptodate())
ext4_read_bh_lock()
ext4_read_bh() -> ... ext4_submit_bh_wbc()
BUG_ON(buffer_unwritten(bh)); /* !!! */

2. The second issue is stale data exposure with page size >= blocksize
with dioread_nolock. The conditions needed for it to happen are same as
the previous issue ie dioread_nolock around ENOSPC condition. The issue
is also similar where in __block_write_begin_int() when we call
ext4_get_block_unwritten() on the buffer_head and the underlying extent
is unwritten, we get an unwritten and mapped buffer head. Since it is
not new, we never zero out the partial range which is not under write,
thus writing stale data to disk. This can be easily observed with the
following reproducer:

fallocate -l 4k testfile
xfs_io -c "pwrite 2k 2k" testfile
# hexdump output will have stale data in from byte 0 to 2k in testfile
hexdump -C testfile

NOTE: To trigger this, we need dioread_nolock enabled and write happening via
ext4_write_begin(), which is usually used when we have -o nodealloc. Since
dioread_nolock is disabled with nodelalloc, the only alternate way to call
ext4_write_begin() is to ensure that delayed alloc switches to nodelalloc ie
ext4_da_write_begin() calls ext4_write_begin(). This will usually happen when
ext4 is almost full like the way generic/269 was triggering it in Issue 1 above.
This might make the issue harder to hit. Hence, for reliable replication, I used
the below patch to temporarily allow dioread_nolock with nodelalloc and then
mount the disk with -o nodealloc,dioread_nolock. With this you can hit the stale
data issue 100% of times:

@@ -508,8 +508,8 @@ static inline int ext4_should_dioread_nolock(struct inode *inode)
if (ext4_should_journal_data(inode))
return 0;
/* temporary fix to prevent generic/422 test failures */
- if (!test_opt(inode->i_sb, DELALLOC))
- return 0;
+ // if (!test_opt(inode->i_sb, DELALLOC))
+ // return 0;
return 1;
}

After applying this patch to mark buffer as NEW, both the above issues are
fixed.

Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Cc: stable@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/d0ed09d70a9733fbb5349c5c7b125caac186ecdf.1695033645.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff 2cd8bdb5 Mon Sep 18 04:45:50 MDT 2023 Ojaswin Mujoo <ojaswin@linux.ibm.com> ext4: mark buffer new if it is unwritten to avoid stale data exposure

** Short Version **

In ext4 with dioread_nolock, we could have a scenario where the bh returned by
get_blocks (ext4_get_block_unwritten()) in __block_write_begin_int() has
UNWRITTEN and MAPPED flag set. Since such a bh does not have NEW flag set we
never zero out the range of bh that is not under write, causing whatever stale
data is present in the folio at that time to be written out to disk. To fix this
mark the buffer as new, in case it is unwritten, in ext4_get_block_unwritten().

** Long Version **

The issue mentioned above was resulting in two different bugs:

1. On block size < page size case in ext4, generic/269 was reliably
failing with dioread_nolock. The state of the write was as follows:

* The write was extending i_size.
* The last block of the file was fallocated and had an unwritten extent
* We were near ENOSPC and hence we were switching to non-delayed alloc
allocation.

In this case, the back trace that triggers the bug is as follows:

ext4_da_write_begin()
/* switch to nodelalloc due to low space */
ext4_write_begin()
ext4_should_dioread_nolock() // true since mount flags still have delalloc
__block_write_begin(..., ext4_get_block_unwritten)
__block_write_begin_int()
for(each buffer head in page) {
/* first iteration, this is bh1 which contains i_size */
if (!buffer_mapped)
get_block() /* returns bh with only UNWRITTEN and MAPPED */
/* second iteration, bh2 */
if (!buffer_mapped)
get_block() /* we fail here, could be ENOSPC */
}
if (err)
/*
* this would zero out all new buffers and mark them uptodate.
* Since bh1 was never marked new, we skip it here which causes
* the bug later.
*/
folio_zero_new_buffers();
/* ext4_wrte_begin() error handling */
ext4_truncate_failed_write()
ext4_truncate()
ext4_block_truncate_page()
__ext4_block_zero_page_range()
if(!buffer_uptodate())
ext4_read_bh_lock()
ext4_read_bh() -> ... ext4_submit_bh_wbc()
BUG_ON(buffer_unwritten(bh)); /* !!! */

2. The second issue is stale data exposure with page size >= blocksize
with dioread_nolock. The conditions needed for it to happen are same as
the previous issue ie dioread_nolock around ENOSPC condition. The issue
is also similar where in __block_write_begin_int() when we call
ext4_get_block_unwritten() on the buffer_head and the underlying extent
is unwritten, we get an unwritten and mapped buffer head. Since it is
not new, we never zero out the partial range which is not under write,
thus writing stale data to disk. This can be easily observed with the
following reproducer:

fallocate -l 4k testfile
xfs_io -c "pwrite 2k 2k" testfile
# hexdump output will have stale data in from byte 0 to 2k in testfile
hexdump -C testfile

NOTE: To trigger this, we need dioread_nolock enabled and write happening via
ext4_write_begin(), which is usually used when we have -o nodealloc. Since
dioread_nolock is disabled with nodelalloc, the only alternate way to call
ext4_write_begin() is to ensure that delayed alloc switches to nodelalloc ie
ext4_da_write_begin() calls ext4_write_begin(). This will usually happen when
ext4 is almost full like the way generic/269 was triggering it in Issue 1 above.
This might make the issue harder to hit. Hence, for reliable replication, I used
the below patch to temporarily allow dioread_nolock with nodelalloc and then
mount the disk with -o nodealloc,dioread_nolock. With this you can hit the stale
data issue 100% of times:

@@ -508,8 +508,8 @@ static inline int ext4_should_dioread_nolock(struct inode *inode)
if (ext4_should_journal_data(inode))
return 0;
/* temporary fix to prevent generic/422 test failures */
- if (!test_opt(inode->i_sb, DELALLOC))
- return 0;
+ // if (!test_opt(inode->i_sb, DELALLOC))
+ // return 0;
return 1;
}

After applying this patch to mark buffer as NEW, both the above issues are
fixed.

Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Cc: stable@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/d0ed09d70a9733fbb5349c5c7b125caac186ecdf.1695033645.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff 2cd8bdb5 Mon Sep 18 04:45:50 MDT 2023 Ojaswin Mujoo <ojaswin@linux.ibm.com> ext4: mark buffer new if it is unwritten to avoid stale data exposure

** Short Version **

In ext4 with dioread_nolock, we could have a scenario where the bh returned by
get_blocks (ext4_get_block_unwritten()) in __block_write_begin_int() has
UNWRITTEN and MAPPED flag set. Since such a bh does not have NEW flag set we
never zero out the range of bh that is not under write, causing whatever stale
data is present in the folio at that time to be written out to disk. To fix this
mark the buffer as new, in case it is unwritten, in ext4_get_block_unwritten().

** Long Version **

The issue mentioned above was resulting in two different bugs:

1. On block size < page size case in ext4, generic/269 was reliably
failing with dioread_nolock. The state of the write was as follows:

* The write was extending i_size.
* The last block of the file was fallocated and had an unwritten extent
* We were near ENOSPC and hence we were switching to non-delayed alloc
allocation.

In this case, the back trace that triggers the bug is as follows:

ext4_da_write_begin()
/* switch to nodelalloc due to low space */
ext4_write_begin()
ext4_should_dioread_nolock() // true since mount flags still have delalloc
__block_write_begin(..., ext4_get_block_unwritten)
__block_write_begin_int()
for(each buffer head in page) {
/* first iteration, this is bh1 which contains i_size */
if (!buffer_mapped)
get_block() /* returns bh with only UNWRITTEN and MAPPED */
/* second iteration, bh2 */
if (!buffer_mapped)
get_block() /* we fail here, could be ENOSPC */
}
if (err)
/*
* this would zero out all new buffers and mark them uptodate.
* Since bh1 was never marked new, we skip it here which causes
* the bug later.
*/
folio_zero_new_buffers();
/* ext4_wrte_begin() error handling */
ext4_truncate_failed_write()
ext4_truncate()
ext4_block_truncate_page()
__ext4_block_zero_page_range()
if(!buffer_uptodate())
ext4_read_bh_lock()
ext4_read_bh() -> ... ext4_submit_bh_wbc()
BUG_ON(buffer_unwritten(bh)); /* !!! */

2. The second issue is stale data exposure with page size >= blocksize
with dioread_nolock. The conditions needed for it to happen are same as
the previous issue ie dioread_nolock around ENOSPC condition. The issue
is also similar where in __block_write_begin_int() when we call
ext4_get_block_unwritten() on the buffer_head and the underlying extent
is unwritten, we get an unwritten and mapped buffer head. Since it is
not new, we never zero out the partial range which is not under write,
thus writing stale data to disk. This can be easily observed with the
following reproducer:

fallocate -l 4k testfile
xfs_io -c "pwrite 2k 2k" testfile
# hexdump output will have stale data in from byte 0 to 2k in testfile
hexdump -C testfile

NOTE: To trigger this, we need dioread_nolock enabled and write happening via
ext4_write_begin(), which is usually used when we have -o nodealloc. Since
dioread_nolock is disabled with nodelalloc, the only alternate way to call
ext4_write_begin() is to ensure that delayed alloc switches to nodelalloc ie
ext4_da_write_begin() calls ext4_write_begin(). This will usually happen when
ext4 is almost full like the way generic/269 was triggering it in Issue 1 above.
This might make the issue harder to hit. Hence, for reliable replication, I used
the below patch to temporarily allow dioread_nolock with nodelalloc and then
mount the disk with -o nodealloc,dioread_nolock. With this you can hit the stale
data issue 100% of times:

@@ -508,8 +508,8 @@ static inline int ext4_should_dioread_nolock(struct inode *inode)
if (ext4_should_journal_data(inode))
return 0;
/* temporary fix to prevent generic/422 test failures */
- if (!test_opt(inode->i_sb, DELALLOC))
- return 0;
+ // if (!test_opt(inode->i_sb, DELALLOC))
+ // return 0;
return 1;
}

After applying this patch to mark buffer as NEW, both the above issues are
fixed.

Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Cc: stable@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/d0ed09d70a9733fbb5349c5c7b125caac186ecdf.1695033645.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff 2cd8bdb5 Mon Sep 18 04:45:50 MDT 2023 Ojaswin Mujoo <ojaswin@linux.ibm.com> ext4: mark buffer new if it is unwritten to avoid stale data exposure

** Short Version **

In ext4 with dioread_nolock, we could have a scenario where the bh returned by
get_blocks (ext4_get_block_unwritten()) in __block_write_begin_int() has
UNWRITTEN and MAPPED flag set. Since such a bh does not have NEW flag set we
never zero out the range of bh that is not under write, causing whatever stale
data is present in the folio at that time to be written out to disk. To fix this
mark the buffer as new, in case it is unwritten, in ext4_get_block_unwritten().

** Long Version **

The issue mentioned above was resulting in two different bugs:

1. On block size < page size case in ext4, generic/269 was reliably
failing with dioread_nolock. The state of the write was as follows:

* The write was extending i_size.
* The last block of the file was fallocated and had an unwritten extent
* We were near ENOSPC and hence we were switching to non-delayed alloc
allocation.

In this case, the back trace that triggers the bug is as follows:

ext4_da_write_begin()
/* switch to nodelalloc due to low space */
ext4_write_begin()
ext4_should_dioread_nolock() // true since mount flags still have delalloc
__block_write_begin(..., ext4_get_block_unwritten)
__block_write_begin_int()
for(each buffer head in page) {
/* first iteration, this is bh1 which contains i_size */
if (!buffer_mapped)
get_block() /* returns bh with only UNWRITTEN and MAPPED */
/* second iteration, bh2 */
if (!buffer_mapped)
get_block() /* we fail here, could be ENOSPC */
}
if (err)
/*
* this would zero out all new buffers and mark them uptodate.
* Since bh1 was never marked new, we skip it here which causes
* the bug later.
*/
folio_zero_new_buffers();
/* ext4_wrte_begin() error handling */
ext4_truncate_failed_write()
ext4_truncate()
ext4_block_truncate_page()
__ext4_block_zero_page_range()
if(!buffer_uptodate())
ext4_read_bh_lock()
ext4_read_bh() -> ... ext4_submit_bh_wbc()
BUG_ON(buffer_unwritten(bh)); /* !!! */

2. The second issue is stale data exposure with page size >= blocksize
with dioread_nolock. The conditions needed for it to happen are same as
the previous issue ie dioread_nolock around ENOSPC condition. The issue
is also similar where in __block_write_begin_int() when we call
ext4_get_block_unwritten() on the buffer_head and the underlying extent
is unwritten, we get an unwritten and mapped buffer head. Since it is
not new, we never zero out the partial range which is not under write,
thus writing stale data to disk. This can be easily observed with the
following reproducer:

fallocate -l 4k testfile
xfs_io -c "pwrite 2k 2k" testfile
# hexdump output will have stale data in from byte 0 to 2k in testfile
hexdump -C testfile

NOTE: To trigger this, we need dioread_nolock enabled and write happening via
ext4_write_begin(), which is usually used when we have -o nodealloc. Since
dioread_nolock is disabled with nodelalloc, the only alternate way to call
ext4_write_begin() is to ensure that delayed alloc switches to nodelalloc ie
ext4_da_write_begin() calls ext4_write_begin(). This will usually happen when
ext4 is almost full like the way generic/269 was triggering it in Issue 1 above.
This might make the issue harder to hit. Hence, for reliable replication, I used
the below patch to temporarily allow dioread_nolock with nodelalloc and then
mount the disk with -o nodealloc,dioread_nolock. With this you can hit the stale
data issue 100% of times:

@@ -508,8 +508,8 @@ static inline int ext4_should_dioread_nolock(struct inode *inode)
if (ext4_should_journal_data(inode))
return 0;
/* temporary fix to prevent generic/422 test failures */
- if (!test_opt(inode->i_sb, DELALLOC))
- return 0;
+ // if (!test_opt(inode->i_sb, DELALLOC))
+ // return 0;
return 1;
}

After applying this patch to mark buffer as NEW, both the above issues are
fixed.

Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Cc: stable@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/d0ed09d70a9733fbb5349c5c7b125caac186ecdf.1695033645.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff 8216776c Mon Aug 14 12:29:01 MDT 2023 Eric Biggers <ebiggers@google.com> ext4: reject casefold inode flag without casefold feature

It is invalid for the casefold inode flag to be set without the casefold
superblock feature flag also being set. e2fsck already considers this
case to be invalid and handles it by offering to clear the casefold flag
on the inode. __ext4_iget() also already considered this to be invalid,
sort of, but it only got so far as logging an error message; it didn't
actually reject the inode. Make it reject the inode so that other code
doesn't have to handle this case. This matches what f2fs does.

Note: we could check 's_encoding != NULL' instead of
ext4_has_feature_casefold(). This would make the check robust against
the casefold feature being enabled by userspace writing to the page
cache of the mounted block device. However, it's unsolvable in general
for filesystems to be robust against concurrent writes to the page cache
of the mounted block device. Though this very particular scenario
involving the casefold feature is solvable, we should not pretend that
we can support this model, so let's just check the casefold feature.
tune2fs already forbids enabling casefold on a mounted filesystem.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20230814182903.37267-2-ebiggers@kernel.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff 03de20be Thu Aug 10 09:43:33 MDT 2023 Liu Song <liusong@linux.alibaba.com> ext4: do not mark inode dirty every time when appending using delalloc

In the delalloc append write scenario, if inode's i_size is extended due
to buffer write, there are delalloc writes pending in the range up to
i_size, and no need to touch i_disksize since writeback will push
i_disksize up to i_size eventually. Offers significant performance
improvement in high-frequency append write scenarios.

I conducted tests in my 32-core environment by launching 32 concurrent
threads to append write to the same file. Each write operation had a
length of 1024 bytes and was repeated 100000 times. Without using this
patch, the test was completed in 7705 ms. However, with this patch, the
test was completed in 5066 ms, resulting in a performance improvement of
34%.

Moreover, in test scenarios of Kafka version 2.6.2, using packet size of
2K, with this patch resulted in a 10% performance improvement.

Signed-off-by: Liu Song <liusong@linux.alibaba.com>
Suggested-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230810154333.84921-1-liusong@linux.alibaba.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff 03de20be Thu Aug 10 09:43:33 MDT 2023 Liu Song <liusong@linux.alibaba.com> ext4: do not mark inode dirty every time when appending using delalloc

In the delalloc append write scenario, if inode's i_size is extended due
to buffer write, there are delalloc writes pending in the range up to
i_size, and no need to touch i_disksize since writeback will push
i_disksize up to i_size eventually. Offers significant performance
improvement in high-frequency append write scenarios.

I conducted tests in my 32-core environment by launching 32 concurrent
threads to append write to the same file. Each write operation had a
length of 1024 bytes and was repeated 100000 times. Without using this
patch, the test was completed in 7705 ms. However, with this patch, the
test was completed in 5066 ms, resulting in a performance improvement of
34%.

Moreover, in test scenarios of Kafka version 2.6.2, using packet size of
2K, with this patch resulted in a 10% performance improvement.

Signed-off-by: Liu Song <liusong@linux.alibaba.com>
Suggested-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230810154333.84921-1-liusong@linux.alibaba.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
/linux-master/fs/f2fs/
H A Dfile.cdiff 2f6d721e Tue Mar 05 20:47:46 MST 2024 Xiuhong Wang <xiuhong.wang@unisoc.com> f2fs: compress: fix reserve_cblocks counting error when out of space

When a file only needs one direct_node, performing the following
operations will cause the file to be unrepairable:

unisoc # ./f2fs_io compress test.apk
unisoc #df -h | grep dm-48
/dev/block/dm-48 112G 112G 1.2M 100% /data

unisoc # ./f2fs_io release_cblocks test.apk
924
unisoc # df -h | grep dm-48
/dev/block/dm-48 112G 112G 4.8M 100% /data

unisoc # dd if=/dev/random of=file4 bs=1M count=3
3145728 bytes (3.0 M) copied, 0.025 s, 120 M/s
unisoc # df -h | grep dm-48
/dev/block/dm-48 112G 112G 1.8M 100% /data

unisoc # ./f2fs_io reserve_cblocks test.apk
F2FS_IOC_RESERVE_COMPRESS_BLOCKS failed: No space left on device

adb reboot
unisoc # df -h | grep dm-48
/dev/block/dm-48 112G 112G 11M 100% /data
unisoc # ./f2fs_io reserve_cblocks test.apk
0

This is because the file has only one direct_node. After returning
to -ENOSPC, reserved_blocks += ret will not be executed. As a result,
the reserved_blocks at this time is still 0, which is not the real
number of reserved blocks. Therefore, fsck cannot be set to repair
the file.

After this patch, the fsck flag will be set to fix this problem.

unisoc # df -h | grep dm-48
/dev/block/dm-48 112G 112G 1.8M 100% /data
unisoc # ./f2fs_io reserve_cblocks test.apk
F2FS_IOC_RESERVE_COMPRESS_BLOCKS failed: No space left on device

adb reboot then fsck will be executed
unisoc # df -h | grep dm-48
/dev/block/dm-48 112G 112G 11M 100% /data
unisoc # ./f2fs_io reserve_cblocks test.apk
924

Fixes: c75488fb4d82 ("f2fs: introduce F2FS_IOC_RESERVE_COMPRESS_BLOCKS")
Signed-off-by: Xiuhong Wang <xiuhong.wang@unisoc.com>
Signed-off-by: Zhiguo Niu <zhiguo.niu@unisoc.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff 2fc2bcc8 Sun Feb 25 20:19:16 MST 2024 Chao Yu <chao@kernel.org> f2fs: fix to check return value in f2fs_insert_range()

In f2fs_insert_range(), it missed to check return value of
filemap_write_and_wait_range(), fix it.

Meanwhile, just return error number once __exchange_data_block()
fails.

Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff 4961acdd Sun Dec 10 04:35:42 MST 2023 Chao Yu <chao@kernel.org> f2fs: fix to tag gcing flag on page during block migration

It needs to add missing gcing flag on page during block migration,
in order to garantee migrated data be persisted during checkpoint,
otherwise out-of-order persistency between data and node may cause
data corruption after SPOR.

Similar issue was fixed by commit 2d1fe8a86bf5 ("f2fs: fix to tag
gcing flag on page during file defragment").

Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff 982c3b30 Tue Oct 24 07:01:08 MDT 2023 Christian Brauner <brauner@kernel.org> bdev: rename freeze and thaw helpers

We have bdev_mark_dead() etc and we're going to move block device
freezing to holder ops in the next patch. Make the naming consistent:

* freeze_bdev() -> bdev_freeze()
* thaw_bdev() -> bdev_thaw()

Also document the return code.

Link: https://lore.kernel.org/r/20231024-vfs-super-freeze-v2-2-599c19f4faac@kernel.org
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff 4ed33e69 Tue Oct 03 16:51:49 MDT 2023 Jaegeuk Kim <jaegeuk@kernel.org> f2fs: stop iterating f2fs_map_block if hole exists

Let's avoid unnecessary f2fs_map_block calls to load extents.

# f2fs_io fadvise willneed 0 4096 /data/local/tmp/test

f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 386, start blkaddr = 0x34ac00, len = 0x1400, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 5506, start blkaddr = 0x34c200, len = 0x1000, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 9602, start blkaddr = 0x34d600, len = 0x1200, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 14210, start blkaddr = 0x34ec00, len = 0x400, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 15235, start blkaddr = 0x34f401, len = 0xbff, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 18306, start blkaddr = 0x350200, len = 0x1200, flags = 2
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 22915, start blkaddr = 0x351601, len = 0xa7d, flags = 2
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25600, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25601, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25602, start blkaddr = 0x351601, len = 0x0, flags = 0
...
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1037188, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1038206, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1039224, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 2075548, start blkaddr = 0x351601, len = 0x0, flags = 0

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff 4ed33e69 Tue Oct 03 16:51:49 MDT 2023 Jaegeuk Kim <jaegeuk@kernel.org> f2fs: stop iterating f2fs_map_block if hole exists

Let's avoid unnecessary f2fs_map_block calls to load extents.

# f2fs_io fadvise willneed 0 4096 /data/local/tmp/test

f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 386, start blkaddr = 0x34ac00, len = 0x1400, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 5506, start blkaddr = 0x34c200, len = 0x1000, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 9602, start blkaddr = 0x34d600, len = 0x1200, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 14210, start blkaddr = 0x34ec00, len = 0x400, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 15235, start blkaddr = 0x34f401, len = 0xbff, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 18306, start blkaddr = 0x350200, len = 0x1200, flags = 2
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 22915, start blkaddr = 0x351601, len = 0xa7d, flags = 2
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25600, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25601, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25602, start blkaddr = 0x351601, len = 0x0, flags = 0
...
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1037188, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1038206, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1039224, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 2075548, start blkaddr = 0x351601, len = 0x0, flags = 0

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff 4ed33e69 Tue Oct 03 16:51:49 MDT 2023 Jaegeuk Kim <jaegeuk@kernel.org> f2fs: stop iterating f2fs_map_block if hole exists

Let's avoid unnecessary f2fs_map_block calls to load extents.

# f2fs_io fadvise willneed 0 4096 /data/local/tmp/test

f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 386, start blkaddr = 0x34ac00, len = 0x1400, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 5506, start blkaddr = 0x34c200, len = 0x1000, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 9602, start blkaddr = 0x34d600, len = 0x1200, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 14210, start blkaddr = 0x34ec00, len = 0x400, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 15235, start blkaddr = 0x34f401, len = 0xbff, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 18306, start blkaddr = 0x350200, len = 0x1200, flags = 2
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 22915, start blkaddr = 0x351601, len = 0xa7d, flags = 2
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25600, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25601, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25602, start blkaddr = 0x351601, len = 0x0, flags = 0
...
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1037188, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1038206, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1039224, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 2075548, start blkaddr = 0x351601, len = 0x0, flags = 0

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff 4ed33e69 Tue Oct 03 16:51:49 MDT 2023 Jaegeuk Kim <jaegeuk@kernel.org> f2fs: stop iterating f2fs_map_block if hole exists

Let's avoid unnecessary f2fs_map_block calls to load extents.

# f2fs_io fadvise willneed 0 4096 /data/local/tmp/test

f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 386, start blkaddr = 0x34ac00, len = 0x1400, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 5506, start blkaddr = 0x34c200, len = 0x1000, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 9602, start blkaddr = 0x34d600, len = 0x1200, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 14210, start blkaddr = 0x34ec00, len = 0x400, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 15235, start blkaddr = 0x34f401, len = 0xbff, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 18306, start blkaddr = 0x350200, len = 0x1200, flags = 2
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 22915, start blkaddr = 0x351601, len = 0xa7d, flags = 2
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25600, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25601, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25602, start blkaddr = 0x351601, len = 0x0, flags = 0
...
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1037188, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1038206, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1039224, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 2075548, start blkaddr = 0x351601, len = 0x0, flags = 0

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff 4ed33e69 Tue Oct 03 16:51:49 MDT 2023 Jaegeuk Kim <jaegeuk@kernel.org> f2fs: stop iterating f2fs_map_block if hole exists

Let's avoid unnecessary f2fs_map_block calls to load extents.

# f2fs_io fadvise willneed 0 4096 /data/local/tmp/test

f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 386, start blkaddr = 0x34ac00, len = 0x1400, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 5506, start blkaddr = 0x34c200, len = 0x1000, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 9602, start blkaddr = 0x34d600, len = 0x1200, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 14210, start blkaddr = 0x34ec00, len = 0x400, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 15235, start blkaddr = 0x34f401, len = 0xbff, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 18306, start blkaddr = 0x350200, len = 0x1200, flags = 2
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 22915, start blkaddr = 0x351601, len = 0xa7d, flags = 2
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25600, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25601, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25602, start blkaddr = 0x351601, len = 0x0, flags = 0
...
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1037188, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1038206, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1039224, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 2075548, start blkaddr = 0x351601, len = 0x0, flags = 0

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff 4ed33e69 Tue Oct 03 16:51:49 MDT 2023 Jaegeuk Kim <jaegeuk@kernel.org> f2fs: stop iterating f2fs_map_block if hole exists

Let's avoid unnecessary f2fs_map_block calls to load extents.

# f2fs_io fadvise willneed 0 4096 /data/local/tmp/test

f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 386, start blkaddr = 0x34ac00, len = 0x1400, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 5506, start blkaddr = 0x34c200, len = 0x1000, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 9602, start blkaddr = 0x34d600, len = 0x1200, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 14210, start blkaddr = 0x34ec00, len = 0x400, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 15235, start blkaddr = 0x34f401, len = 0xbff, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 18306, start blkaddr = 0x350200, len = 0x1200, flags = 2
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 22915, start blkaddr = 0x351601, len = 0xa7d, flags = 2
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25600, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25601, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25602, start blkaddr = 0x351601, len = 0x0, flags = 0
...
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1037188, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1038206, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1039224, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 2075548, start blkaddr = 0x351601, len = 0x0, flags = 0

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff 4ed33e69 Tue Oct 03 16:51:49 MDT 2023 Jaegeuk Kim <jaegeuk@kernel.org> f2fs: stop iterating f2fs_map_block if hole exists

Let's avoid unnecessary f2fs_map_block calls to load extents.

# f2fs_io fadvise willneed 0 4096 /data/local/tmp/test

f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 386, start blkaddr = 0x34ac00, len = 0x1400, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 5506, start blkaddr = 0x34c200, len = 0x1000, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 9602, start blkaddr = 0x34d600, len = 0x1200, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 14210, start blkaddr = 0x34ec00, len = 0x400, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 15235, start blkaddr = 0x34f401, len = 0xbff, flags = 2,
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 18306, start blkaddr = 0x350200, len = 0x1200, flags = 2
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 22915, start blkaddr = 0x351601, len = 0xa7d, flags = 2
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25600, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25601, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 25602, start blkaddr = 0x351601, len = 0x0, flags = 0
...
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1037188, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1038206, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 1039224, start blkaddr = 0x351601, len = 0x0, flags = 0
f2fs_map_blocks: dev = (254,51), ino = 85845, file offset = 2075548, start blkaddr = 0x351601, len = 0x0, flags = 0

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
/linux-master/fs/fat/
H A Dfile.cdiff 0d72b928 Mon Aug 07 13:38:33 MDT 2023 Jeff Layton <jlayton@kernel.org> fs: pass the request_mask to generic_fillattr

generic_fillattr just fills in the entire stat struct indiscriminately
today, copying data from the inode. There is at least one attribute
(STATX_CHANGE_COOKIE) that can have side effects when it is reported,
and we're looking at adding more with the addition of multigrain
timestamps.

Add a request_mask argument to generic_fillattr and have most callers
just pass in the value that is passed to getattr. Have other callers
(e.g. ksmbd) just pass in STATX_BASIC_STATS. Also move the setting of
STATX_CHANGE_COOKIE into generic_fillattr.

Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: "Paulo Alcantara (SUSE)" <pc@manguebit.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Message-Id: <20230807-mgctime-v7-2-d1dec143a704@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff 2cb1e089 Mon May 22 07:50:15 MDT 2023 David Howells <dhowells@redhat.com> splice: Use filemap_splice_read() instead of generic_file_splice_read()

Replace pointers to generic_file_splice_read() with calls to
filemap_splice_read().

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: David Hildenbrand <david@redhat.com>
cc: John Hubbard <jhubbard@nvidia.com>
cc: linux-mm@kvack.org
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20230522135018.2742245-29-dhowells@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff a528d35e Tue Jan 31 09:46:22 MST 2017 David Howells <dhowells@redhat.com> statx: Add a system call to make enhanced file info available

Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.

The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode. This change is propagated to the vfs_getattr*()
function.

Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.

========
OVERVIEW
========

The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preference proved to be for a new syscall
with an extended stat structure.

A number of requests were gathered for features to be included. The
following have been included:

(1) Make the fields a consistent size on all arches and make them large.

(2) Spare space, request flags and information flags are provided for
future expansion.

(3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
__s64).

(4) Creation time: The SMB protocol carries the creation time, which could
be exported by Samba, which will in turn help CIFS make use of
FS-Cache as that can be used for coherency data (stx_btime).

This is also specified in NFSv4 as a recommended attribute and could
be exported by NFSD [Steve French].

(5) Lightweight stat: Ask for just those details of interest, and allow a
netfs (such as NFS) to approximate anything not of interest, possibly
without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
Dilger] (AT_STATX_DONT_SYNC).

(6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
its cached attributes are up to date [Trond Myklebust]
(AT_STATX_FORCE_SYNC).

And the following have been left out for future extension:

(7) Data version number: Could be used by userspace NFS servers [Aneesh
Kumar].

Can also be used to modify fill_post_wcc() in NFSD which retrieves
i_version directly, but has just called vfs_getattr(). It could get
it from the kstat struct if it used vfs_xgetattr() instead.

(There's disagreement on the exact semantics of a single field, since
not all filesystems do this the same way).

(8) BSD stat compatibility: Including more fields from the BSD stat such
as creation time (st_btime) and inode generation number (st_gen)
[Jeremy Allison, Bernd Schubert].

(9) Inode generation number: Useful for FUSE and userspace NFS servers
[Bernd Schubert].

(This was asked for but later deemed unnecessary with the
open-by-handle capability available and caused disagreement as to
whether it's a security hole or not).

(10) Extra coherency data may be useful in making backups [Andreas Dilger].

(No particular data were offered, but things like last backup
timestamp, the data version number and the DOS archive bit would come
into this category).

(11) Allow the filesystem to indicate what it can/cannot provide: A
filesystem can now say it doesn't support a standard stat feature if
that isn't available, so if, for instance, inode numbers or UIDs don't
exist or are fabricated locally...

(This requires a separate system call - I have an fsinfo() call idea
for this).

(12) Store a 16-byte volume ID in the superblock that can be returned in
struct xstat [Steve French].

(Deferred to fsinfo).

(13) Include granularity fields in the time data to indicate the
granularity of each of the times (NFSv4 time_delta) [Steve French].

(Deferred to fsinfo).

(14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags.
Note that the Linux IOC flags are a mess and filesystems such as Ext4
define flags that aren't in linux/fs.h, so translation in the kernel
may be a necessity (or, possibly, we provide the filesystem type too).

(Some attributes are made available in stx_attributes, but the general
feeling was that the IOC flags were to ext[234]-specific and shouldn't
be exposed through statx this way).

(15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
Michael Kerrisk].

(Deferred, probably to fsinfo. Finding out if there's an ACL or
seclabal might require extra filesystem operations).

(16) Femtosecond-resolution timestamps [Dave Chinner].

(A __reserved field has been left in the statx_timestamp struct for
this - if there proves to be a need).

(17) A set multiple attributes syscall to go with this.

===============
NEW SYSTEM CALL
===============

The new system call is:

int ret = statx(int dfd,
const char *filename,
unsigned int flags,
unsigned int mask,
struct statx *buffer);

The dfd, filename and flags parameters indicate the file to query, in a
similar way to fstatat(). There is no equivalent of lstat() as that can be
emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is
also no equivalent of fstat() as that can be emulated by passing a NULL
filename to statx() with the fd of interest in dfd.

Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):

(1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
respect.

(2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
its attributes with the server - which might require data writeback to
occur to get the timestamps correct.

(3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
network filesystem. The resulting values should be considered
approximate.

mask is a bitmask indicating the fields in struct statx that are of
interest to the caller. The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat(). It should be noted that asking for
more information may entail extra I/O operations.

buffer points to the destination for the data. This must be 256 bytes in
size.

======================
MAIN ATTRIBUTES RECORD
======================

The following structures are defined in which to return the main attribute
set:

struct statx_timestamp {
__s64 tv_sec;
__s32 tv_nsec;
__s32 __reserved;
};

struct statx {
__u32 stx_mask;
__u32 stx_blksize;
__u64 stx_attributes;
__u32 stx_nlink;
__u32 stx_uid;
__u32 stx_gid;
__u16 stx_mode;
__u16 __spare0[1];
__u64 stx_ino;
__u64 stx_size;
__u64 stx_blocks;
__u64 __spare1[1];
struct statx_timestamp stx_atime;
struct statx_timestamp stx_btime;
struct statx_timestamp stx_ctime;
struct statx_timestamp stx_mtime;
__u32 stx_rdev_major;
__u32 stx_rdev_minor;
__u32 stx_dev_major;
__u32 stx_dev_minor;
__u64 __spare2[14];
};

The defined bits in request_mask and stx_mask are:

STATX_TYPE Want/got stx_mode & S_IFMT
STATX_MODE Want/got stx_mode & ~S_IFMT
STATX_NLINK Want/got stx_nlink
STATX_UID Want/got stx_uid
STATX_GID Want/got stx_gid
STATX_ATIME Want/got stx_atime{,_ns}
STATX_MTIME Want/got stx_mtime{,_ns}
STATX_CTIME Want/got stx_ctime{,_ns}
STATX_INO Want/got stx_ino
STATX_SIZE Want/got stx_size
STATX_BLOCKS Want/got stx_blocks
STATX_BASIC_STATS [The stuff in the normal stat struct]
STATX_BTIME Want/got stx_btime{,_ns}
STATX_ALL [All currently available stuff]

stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.

Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution. Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.

The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does. The following
attributes map to FS_*_FL flags and are the same numerical value:

STATX_ATTR_COMPRESSED File is compressed by the fs
STATX_ATTR_IMMUTABLE File is marked immutable
STATX_ATTR_APPEND File is append-only
STATX_ATTR_NODUMP File is not to be dumped
STATX_ATTR_ENCRYPTED File requires key to decrypt in fs

Within the kernel, the supported flags are listed by:

KSTAT_ATTR_FS_IOC_FLAGS

[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]

New flags include:

STATX_ATTR_AUTOMOUNT Object is an automount trigger

These are for the use of GUI tools that might want to mark files specially,
depending on what they are.

Fields in struct statx come in a number of classes:

(0) stx_dev_*, stx_blksize.

These are local system information and are always available.

(1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
stx_size, stx_blocks.

These will be returned whether the caller asks for them or not. The
corresponding bits in stx_mask will be set to indicate whether they
actually have valid values.

If the caller didn't ask for them, then they may be approximated. For
example, NFS won't waste any time updating them from the server,
unless as a byproduct of updating something requested.

If the values don't actually exist for the underlying object (such as
UID or GID on a DOS file), then the bit won't be set in the stx_mask,
even if the caller asked for the value. In such a case, the returned
value will be a fabrication.

Note that there are instances where the type might not be valid, for
instance Windows reparse points.

(2) stx_rdev_*.

This will be set only if stx_mode indicates we're looking at a
blockdev or a chardev, otherwise will be 0.

(3) stx_btime.

Similar to (1), except this will be set to 0 if it doesn't exist.

=======
TESTING
=======

The following test program can be used to test the statx system call:

samples/statx/test-statx.c

Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.

Here's some example output. Firstly, an NFS directory that crosses to
another FSID. Note that the AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.

[root@andromeda ~]# /tmp/test-statx -A /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:26 Inode: 1703937 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)

Secondly, the result of automounting on that directory.

[root@andromeda ~]# /tmp/test-statx /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:27 Inode: 2 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff a528d35e Tue Jan 31 09:46:22 MST 2017 David Howells <dhowells@redhat.com> statx: Add a system call to make enhanced file info available

Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.

The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode. This change is propagated to the vfs_getattr*()
function.

Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.

========
OVERVIEW
========

The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preference proved to be for a new syscall
with an extended stat structure.

A number of requests were gathered for features to be included. The
following have been included:

(1) Make the fields a consistent size on all arches and make them large.

(2) Spare space, request flags and information flags are provided for
future expansion.

(3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
__s64).

(4) Creation time: The SMB protocol carries the creation time, which could
be exported by Samba, which will in turn help CIFS make use of
FS-Cache as that can be used for coherency data (stx_btime).

This is also specified in NFSv4 as a recommended attribute and could
be exported by NFSD [Steve French].

(5) Lightweight stat: Ask for just those details of interest, and allow a
netfs (such as NFS) to approximate anything not of interest, possibly
without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
Dilger] (AT_STATX_DONT_SYNC).

(6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
its cached attributes are up to date [Trond Myklebust]
(AT_STATX_FORCE_SYNC).

And the following have been left out for future extension:

(7) Data version number: Could be used by userspace NFS servers [Aneesh
Kumar].

Can also be used to modify fill_post_wcc() in NFSD which retrieves
i_version directly, but has just called vfs_getattr(). It could get
it from the kstat struct if it used vfs_xgetattr() instead.

(There's disagreement on the exact semantics of a single field, since
not all filesystems do this the same way).

(8) BSD stat compatibility: Including more fields from the BSD stat such
as creation time (st_btime) and inode generation number (st_gen)
[Jeremy Allison, Bernd Schubert].

(9) Inode generation number: Useful for FUSE and userspace NFS servers
[Bernd Schubert].

(This was asked for but later deemed unnecessary with the
open-by-handle capability available and caused disagreement as to
whether it's a security hole or not).

(10) Extra coherency data may be useful in making backups [Andreas Dilger].

(No particular data were offered, but things like last backup
timestamp, the data version number and the DOS archive bit would come
into this category).

(11) Allow the filesystem to indicate what it can/cannot provide: A
filesystem can now say it doesn't support a standard stat feature if
that isn't available, so if, for instance, inode numbers or UIDs don't
exist or are fabricated locally...

(This requires a separate system call - I have an fsinfo() call idea
for this).

(12) Store a 16-byte volume ID in the superblock that can be returned in
struct xstat [Steve French].

(Deferred to fsinfo).

(13) Include granularity fields in the time data to indicate the
granularity of each of the times (NFSv4 time_delta) [Steve French].

(Deferred to fsinfo).

(14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags.
Note that the Linux IOC flags are a mess and filesystems such as Ext4
define flags that aren't in linux/fs.h, so translation in the kernel
may be a necessity (or, possibly, we provide the filesystem type too).

(Some attributes are made available in stx_attributes, but the general
feeling was that the IOC flags were to ext[234]-specific and shouldn't
be exposed through statx this way).

(15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
Michael Kerrisk].

(Deferred, probably to fsinfo. Finding out if there's an ACL or
seclabal might require extra filesystem operations).

(16) Femtosecond-resolution timestamps [Dave Chinner].

(A __reserved field has been left in the statx_timestamp struct for
this - if there proves to be a need).

(17) A set multiple attributes syscall to go with this.

===============
NEW SYSTEM CALL
===============

The new system call is:

int ret = statx(int dfd,
const char *filename,
unsigned int flags,
unsigned int mask,
struct statx *buffer);

The dfd, filename and flags parameters indicate the file to query, in a
similar way to fstatat(). There is no equivalent of lstat() as that can be
emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is
also no equivalent of fstat() as that can be emulated by passing a NULL
filename to statx() with the fd of interest in dfd.

Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):

(1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
respect.

(2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
its attributes with the server - which might require data writeback to
occur to get the timestamps correct.

(3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
network filesystem. The resulting values should be considered
approximate.

mask is a bitmask indicating the fields in struct statx that are of
interest to the caller. The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat(). It should be noted that asking for
more information may entail extra I/O operations.

buffer points to the destination for the data. This must be 256 bytes in
size.

======================
MAIN ATTRIBUTES RECORD
======================

The following structures are defined in which to return the main attribute
set:

struct statx_timestamp {
__s64 tv_sec;
__s32 tv_nsec;
__s32 __reserved;
};

struct statx {
__u32 stx_mask;
__u32 stx_blksize;
__u64 stx_attributes;
__u32 stx_nlink;
__u32 stx_uid;
__u32 stx_gid;
__u16 stx_mode;
__u16 __spare0[1];
__u64 stx_ino;
__u64 stx_size;
__u64 stx_blocks;
__u64 __spare1[1];
struct statx_timestamp stx_atime;
struct statx_timestamp stx_btime;
struct statx_timestamp stx_ctime;
struct statx_timestamp stx_mtime;
__u32 stx_rdev_major;
__u32 stx_rdev_minor;
__u32 stx_dev_major;
__u32 stx_dev_minor;
__u64 __spare2[14];
};

The defined bits in request_mask and stx_mask are:

STATX_TYPE Want/got stx_mode & S_IFMT
STATX_MODE Want/got stx_mode & ~S_IFMT
STATX_NLINK Want/got stx_nlink
STATX_UID Want/got stx_uid
STATX_GID Want/got stx_gid
STATX_ATIME Want/got stx_atime{,_ns}
STATX_MTIME Want/got stx_mtime{,_ns}
STATX_CTIME Want/got stx_ctime{,_ns}
STATX_INO Want/got stx_ino
STATX_SIZE Want/got stx_size
STATX_BLOCKS Want/got stx_blocks
STATX_BASIC_STATS [The stuff in the normal stat struct]
STATX_BTIME Want/got stx_btime{,_ns}
STATX_ALL [All currently available stuff]

stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.

Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution. Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.

The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does. The following
attributes map to FS_*_FL flags and are the same numerical value:

STATX_ATTR_COMPRESSED File is compressed by the fs
STATX_ATTR_IMMUTABLE File is marked immutable
STATX_ATTR_APPEND File is append-only
STATX_ATTR_NODUMP File is not to be dumped
STATX_ATTR_ENCRYPTED File requires key to decrypt in fs

Within the kernel, the supported flags are listed by:

KSTAT_ATTR_FS_IOC_FLAGS

[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]

New flags include:

STATX_ATTR_AUTOMOUNT Object is an automount trigger

These are for the use of GUI tools that might want to mark files specially,
depending on what they are.

Fields in struct statx come in a number of classes:

(0) stx_dev_*, stx_blksize.

These are local system information and are always available.

(1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
stx_size, stx_blocks.

These will be returned whether the caller asks for them or not. The
corresponding bits in stx_mask will be set to indicate whether they
actually have valid values.

If the caller didn't ask for them, then they may be approximated. For
example, NFS won't waste any time updating them from the server,
unless as a byproduct of updating something requested.

If the values don't actually exist for the underlying object (such as
UID or GID on a DOS file), then the bit won't be set in the stx_mask,
even if the caller asked for the value. In such a case, the returned
value will be a fabrication.

Note that there are instances where the type might not be valid, for
instance Windows reparse points.

(2) stx_rdev_*.

This will be set only if stx_mode indicates we're looking at a
blockdev or a chardev, otherwise will be 0.

(3) stx_btime.

Similar to (1), except this will be set to 0 if it doesn't exist.

=======
TESTING
=======

The following test program can be used to test the statx system call:

samples/statx/test-statx.c

Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.

Here's some example output. Firstly, an NFS directory that crosses to
another FSID. Note that the AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.

[root@andromeda ~]# /tmp/test-statx -A /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:26 Inode: 1703937 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)

Secondly, the result of automounting on that directory.

[root@andromeda ~]# /tmp/test-statx /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:27 Inode: 2 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff a528d35e Tue Jan 31 09:46:22 MST 2017 David Howells <dhowells@redhat.com> statx: Add a system call to make enhanced file info available

Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.

The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode. This change is propagated to the vfs_getattr*()
function.

Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.

========
OVERVIEW
========

The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preference proved to be for a new syscall
with an extended stat structure.

A number of requests were gathered for features to be included. The
following have been included:

(1) Make the fields a consistent size on all arches and make them large.

(2) Spare space, request flags and information flags are provided for
future expansion.

(3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
__s64).

(4) Creation time: The SMB protocol carries the creation time, which could
be exported by Samba, which will in turn help CIFS make use of
FS-Cache as that can be used for coherency data (stx_btime).

This is also specified in NFSv4 as a recommended attribute and could
be exported by NFSD [Steve French].

(5) Lightweight stat: Ask for just those details of interest, and allow a
netfs (such as NFS) to approximate anything not of interest, possibly
without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
Dilger] (AT_STATX_DONT_SYNC).

(6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
its cached attributes are up to date [Trond Myklebust]
(AT_STATX_FORCE_SYNC).

And the following have been left out for future extension:

(7) Data version number: Could be used by userspace NFS servers [Aneesh
Kumar].

Can also be used to modify fill_post_wcc() in NFSD which retrieves
i_version directly, but has just called vfs_getattr(). It could get
it from the kstat struct if it used vfs_xgetattr() instead.

(There's disagreement on the exact semantics of a single field, since
not all filesystems do this the same way).

(8) BSD stat compatibility: Including more fields from the BSD stat such
as creation time (st_btime) and inode generation number (st_gen)
[Jeremy Allison, Bernd Schubert].

(9) Inode generation number: Useful for FUSE and userspace NFS servers
[Bernd Schubert].

(This was asked for but later deemed unnecessary with the
open-by-handle capability available and caused disagreement as to
whether it's a security hole or not).

(10) Extra coherency data may be useful in making backups [Andreas Dilger].

(No particular data were offered, but things like last backup
timestamp, the data version number and the DOS archive bit would come
into this category).

(11) Allow the filesystem to indicate what it can/cannot provide: A
filesystem can now say it doesn't support a standard stat feature if
that isn't available, so if, for instance, inode numbers or UIDs don't
exist or are fabricated locally...

(This requires a separate system call - I have an fsinfo() call idea
for this).

(12) Store a 16-byte volume ID in the superblock that can be returned in
struct xstat [Steve French].

(Deferred to fsinfo).

(13) Include granularity fields in the time data to indicate the
granularity of each of the times (NFSv4 time_delta) [Steve French].

(Deferred to fsinfo).

(14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags.
Note that the Linux IOC flags are a mess and filesystems such as Ext4
define flags that aren't in linux/fs.h, so translation in the kernel
may be a necessity (or, possibly, we provide the filesystem type too).

(Some attributes are made available in stx_attributes, but the general
feeling was that the IOC flags were to ext[234]-specific and shouldn't
be exposed through statx this way).

(15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
Michael Kerrisk].

(Deferred, probably to fsinfo. Finding out if there's an ACL or
seclabal might require extra filesystem operations).

(16) Femtosecond-resolution timestamps [Dave Chinner].

(A __reserved field has been left in the statx_timestamp struct for
this - if there proves to be a need).

(17) A set multiple attributes syscall to go with this.

===============
NEW SYSTEM CALL
===============

The new system call is:

int ret = statx(int dfd,
const char *filename,
unsigned int flags,
unsigned int mask,
struct statx *buffer);

The dfd, filename and flags parameters indicate the file to query, in a
similar way to fstatat(). There is no equivalent of lstat() as that can be
emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is
also no equivalent of fstat() as that can be emulated by passing a NULL
filename to statx() with the fd of interest in dfd.

Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):

(1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
respect.

(2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
its attributes with the server - which might require data writeback to
occur to get the timestamps correct.

(3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
network filesystem. The resulting values should be considered
approximate.

mask is a bitmask indicating the fields in struct statx that are of
interest to the caller. The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat(). It should be noted that asking for
more information may entail extra I/O operations.

buffer points to the destination for the data. This must be 256 bytes in
size.

======================
MAIN ATTRIBUTES RECORD
======================

The following structures are defined in which to return the main attribute
set:

struct statx_timestamp {
__s64 tv_sec;
__s32 tv_nsec;
__s32 __reserved;
};

struct statx {
__u32 stx_mask;
__u32 stx_blksize;
__u64 stx_attributes;
__u32 stx_nlink;
__u32 stx_uid;
__u32 stx_gid;
__u16 stx_mode;
__u16 __spare0[1];
__u64 stx_ino;
__u64 stx_size;
__u64 stx_blocks;
__u64 __spare1[1];
struct statx_timestamp stx_atime;
struct statx_timestamp stx_btime;
struct statx_timestamp stx_ctime;
struct statx_timestamp stx_mtime;
__u32 stx_rdev_major;
__u32 stx_rdev_minor;
__u32 stx_dev_major;
__u32 stx_dev_minor;
__u64 __spare2[14];
};

The defined bits in request_mask and stx_mask are:

STATX_TYPE Want/got stx_mode & S_IFMT
STATX_MODE Want/got stx_mode & ~S_IFMT
STATX_NLINK Want/got stx_nlink
STATX_UID Want/got stx_uid
STATX_GID Want/got stx_gid
STATX_ATIME Want/got stx_atime{,_ns}
STATX_MTIME Want/got stx_mtime{,_ns}
STATX_CTIME Want/got stx_ctime{,_ns}
STATX_INO Want/got stx_ino
STATX_SIZE Want/got stx_size
STATX_BLOCKS Want/got stx_blocks
STATX_BASIC_STATS [The stuff in the normal stat struct]
STATX_BTIME Want/got stx_btime{,_ns}
STATX_ALL [All currently available stuff]

stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.

Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution. Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.

The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does. The following
attributes map to FS_*_FL flags and are the same numerical value:

STATX_ATTR_COMPRESSED File is compressed by the fs
STATX_ATTR_IMMUTABLE File is marked immutable
STATX_ATTR_APPEND File is append-only
STATX_ATTR_NODUMP File is not to be dumped
STATX_ATTR_ENCRYPTED File requires key to decrypt in fs

Within the kernel, the supported flags are listed by:

KSTAT_ATTR_FS_IOC_FLAGS

[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]

New flags include:

STATX_ATTR_AUTOMOUNT Object is an automount trigger

These are for the use of GUI tools that might want to mark files specially,
depending on what they are.

Fields in struct statx come in a number of classes:

(0) stx_dev_*, stx_blksize.

These are local system information and are always available.

(1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
stx_size, stx_blocks.

These will be returned whether the caller asks for them or not. The
corresponding bits in stx_mask will be set to indicate whether they
actually have valid values.

If the caller didn't ask for them, then they may be approximated. For
example, NFS won't waste any time updating them from the server,
unless as a byproduct of updating something requested.

If the values don't actually exist for the underlying object (such as
UID or GID on a DOS file), then the bit won't be set in the stx_mask,
even if the caller asked for the value. In such a case, the returned
value will be a fabrication.

Note that there are instances where the type might not be valid, for
instance Windows reparse points.

(2) stx_rdev_*.

This will be set only if stx_mode indicates we're looking at a
blockdev or a chardev, otherwise will be 0.

(3) stx_btime.

Similar to (1), except this will be set to 0 if it doesn't exist.

=======
TESTING
=======

The following test program can be used to test the statx system call:

samples/statx/test-statx.c

Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.

Here's some example output. Firstly, an NFS directory that crosses to
another FSID. Note that the AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.

[root@andromeda ~]# /tmp/test-statx -A /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:26 Inode: 1703937 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)

Secondly, the result of automounting on that directory.

[root@andromeda ~]# /tmp/test-statx /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:27 Inode: 2 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff a528d35e Tue Jan 31 09:46:22 MST 2017 David Howells <dhowells@redhat.com> statx: Add a system call to make enhanced file info available

Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.

The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode. This change is propagated to the vfs_getattr*()
function.

Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.

========
OVERVIEW
========

The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preference proved to be for a new syscall
with an extended stat structure.

A number of requests were gathered for features to be included. The
following have been included:

(1) Make the fields a consistent size on all arches and make them large.

(2) Spare space, request flags and information flags are provided for
future expansion.

(3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
__s64).

(4) Creation time: The SMB protocol carries the creation time, which could
be exported by Samba, which will in turn help CIFS make use of
FS-Cache as that can be used for coherency data (stx_btime).

This is also specified in NFSv4 as a recommended attribute and could
be exported by NFSD [Steve French].

(5) Lightweight stat: Ask for just those details of interest, and allow a
netfs (such as NFS) to approximate anything not of interest, possibly
without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
Dilger] (AT_STATX_DONT_SYNC).

(6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
its cached attributes are up to date [Trond Myklebust]
(AT_STATX_FORCE_SYNC).

And the following have been left out for future extension:

(7) Data version number: Could be used by userspace NFS servers [Aneesh
Kumar].

Can also be used to modify fill_post_wcc() in NFSD which retrieves
i_version directly, but has just called vfs_getattr(). It could get
it from the kstat struct if it used vfs_xgetattr() instead.

(There's disagreement on the exact semantics of a single field, since
not all filesystems do this the same way).

(8) BSD stat compatibility: Including more fields from the BSD stat such
as creation time (st_btime) and inode generation number (st_gen)
[Jeremy Allison, Bernd Schubert].

(9) Inode generation number: Useful for FUSE and userspace NFS servers
[Bernd Schubert].

(This was asked for but later deemed unnecessary with the
open-by-handle capability available and caused disagreement as to
whether it's a security hole or not).

(10) Extra coherency data may be useful in making backups [Andreas Dilger].

(No particular data were offered, but things like last backup
timestamp, the data version number and the DOS archive bit would come
into this category).

(11) Allow the filesystem to indicate what it can/cannot provide: A
filesystem can now say it doesn't support a standard stat feature if
that isn't available, so if, for instance, inode numbers or UIDs don't
exist or are fabricated locally...

(This requires a separate system call - I have an fsinfo() call idea
for this).

(12) Store a 16-byte volume ID in the superblock that can be returned in
struct xstat [Steve French].

(Deferred to fsinfo).

(13) Include granularity fields in the time data to indicate the
granularity of each of the times (NFSv4 time_delta) [Steve French].

(Deferred to fsinfo).

(14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags.
Note that the Linux IOC flags are a mess and filesystems such as Ext4
define flags that aren't in linux/fs.h, so translation in the kernel
may be a necessity (or, possibly, we provide the filesystem type too).

(Some attributes are made available in stx_attributes, but the general
feeling was that the IOC flags were to ext[234]-specific and shouldn't
be exposed through statx this way).

(15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
Michael Kerrisk].

(Deferred, probably to fsinfo. Finding out if there's an ACL or
seclabal might require extra filesystem operations).

(16) Femtosecond-resolution timestamps [Dave Chinner].

(A __reserved field has been left in the statx_timestamp struct for
this - if there proves to be a need).

(17) A set multiple attributes syscall to go with this.

===============
NEW SYSTEM CALL
===============

The new system call is:

int ret = statx(int dfd,
const char *filename,
unsigned int flags,
unsigned int mask,
struct statx *buffer);

The dfd, filename and flags parameters indicate the file to query, in a
similar way to fstatat(). There is no equivalent of lstat() as that can be
emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is
also no equivalent of fstat() as that can be emulated by passing a NULL
filename to statx() with the fd of interest in dfd.

Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):

(1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
respect.

(2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
its attributes with the server - which might require data writeback to
occur to get the timestamps correct.

(3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
network filesystem. The resulting values should be considered
approximate.

mask is a bitmask indicating the fields in struct statx that are of
interest to the caller. The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat(). It should be noted that asking for
more information may entail extra I/O operations.

buffer points to the destination for the data. This must be 256 bytes in
size.

======================
MAIN ATTRIBUTES RECORD
======================

The following structures are defined in which to return the main attribute
set:

struct statx_timestamp {
__s64 tv_sec;
__s32 tv_nsec;
__s32 __reserved;
};

struct statx {
__u32 stx_mask;
__u32 stx_blksize;
__u64 stx_attributes;
__u32 stx_nlink;
__u32 stx_uid;
__u32 stx_gid;
__u16 stx_mode;
__u16 __spare0[1];
__u64 stx_ino;
__u64 stx_size;
__u64 stx_blocks;
__u64 __spare1[1];
struct statx_timestamp stx_atime;
struct statx_timestamp stx_btime;
struct statx_timestamp stx_ctime;
struct statx_timestamp stx_mtime;
__u32 stx_rdev_major;
__u32 stx_rdev_minor;
__u32 stx_dev_major;
__u32 stx_dev_minor;
__u64 __spare2[14];
};

The defined bits in request_mask and stx_mask are:

STATX_TYPE Want/got stx_mode & S_IFMT
STATX_MODE Want/got stx_mode & ~S_IFMT
STATX_NLINK Want/got stx_nlink
STATX_UID Want/got stx_uid
STATX_GID Want/got stx_gid
STATX_ATIME Want/got stx_atime{,_ns}
STATX_MTIME Want/got stx_mtime{,_ns}
STATX_CTIME Want/got stx_ctime{,_ns}
STATX_INO Want/got stx_ino
STATX_SIZE Want/got stx_size
STATX_BLOCKS Want/got stx_blocks
STATX_BASIC_STATS [The stuff in the normal stat struct]
STATX_BTIME Want/got stx_btime{,_ns}
STATX_ALL [All currently available stuff]

stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.

Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution. Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.

The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does. The following
attributes map to FS_*_FL flags and are the same numerical value:

STATX_ATTR_COMPRESSED File is compressed by the fs
STATX_ATTR_IMMUTABLE File is marked immutable
STATX_ATTR_APPEND File is append-only
STATX_ATTR_NODUMP File is not to be dumped
STATX_ATTR_ENCRYPTED File requires key to decrypt in fs

Within the kernel, the supported flags are listed by:

KSTAT_ATTR_FS_IOC_FLAGS

[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]

New flags include:

STATX_ATTR_AUTOMOUNT Object is an automount trigger

These are for the use of GUI tools that might want to mark files specially,
depending on what they are.

Fields in struct statx come in a number of classes:

(0) stx_dev_*, stx_blksize.

These are local system information and are always available.

(1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
stx_size, stx_blocks.

These will be returned whether the caller asks for them or not. The
corresponding bits in stx_mask will be set to indicate whether they
actually have valid values.

If the caller didn't ask for them, then they may be approximated. For
example, NFS won't waste any time updating them from the server,
unless as a byproduct of updating something requested.

If the values don't actually exist for the underlying object (such as
UID or GID on a DOS file), then the bit won't be set in the stx_mask,
even if the caller asked for the value. In such a case, the returned
value will be a fabrication.

Note that there are instances where the type might not be valid, for
instance Windows reparse points.

(2) stx_rdev_*.

This will be set only if stx_mode indicates we're looking at a
blockdev or a chardev, otherwise will be 0.

(3) stx_btime.

Similar to (1), except this will be set to 0 if it doesn't exist.

=======
TESTING
=======

The following test program can be used to test the statx system call:

samples/statx/test-statx.c

Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.

Here's some example output. Firstly, an NFS directory that crosses to
another FSID. Note that the AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.

[root@andromeda ~]# /tmp/test-statx -A /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:26 Inode: 1703937 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000
Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)

Secondly, the result of automounting on that directory.

[root@andromeda ~]# /tmp/test-statx /warthog/data
statx(/warthog/data) = 0
results=7ff
Size: 4096 Blocks: 8 IO Block: 1048576 directory
Device: 00:27 Inode: 2 Links: 125
Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041
Access: 2016-11-24 09:02:12.219699527+0000
Modify: 2016-11-17 10:44:36.225653653+0000
Change: 2016-11-17 10:44:36.225653653+0000

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff 2b0143b5 Tue Mar 17 16:25:59 MDT 2015 David Howells <dhowells@redhat.com> VFS: normal filesystems (and lustre): d_inode() annotations

that's the bulk of filesystem drivers dealing with inodes of their own

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff 2a79f17e Fri Dec 09 06:06:57 MST 2011 Al Viro <viro@zeniv.linux.org.uk> vfs: mnt_drop_write_file()

new helper (wrapper around mnt_drop_write()) to be used in pair with
mnt_want_write_file().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
/linux-master/fs/fuse/
H A Ddir.cdiff 2d09ab22 Fri Jan 05 08:21:27 MST 2024 Alexander Mikhalitsyn <alexander@mihalicyn.com> fuse: fix typo for fuse_permission comment

Found by chance while working on support for idmapped mounts in fuse.

Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
diff 972f4c46 Wed Aug 09 16:45:05 MDT 2023 Miklos Szeredi <mszeredi@redhat.com> fuse: cache btime

Not all inode attributes are supported by all filesystems, but for the
basic stats (which are returned by stat(2) and friends) all of them will
have some value, even if that doesn't reflect a real attribute of the file.

Btime is different, in that filesystems are free to report or not report a
value in statx. If the value is available, then STATX_BTIME bit is set in
stx_mask.

When caching the value of btime, remember the availability of the attribute
as well as the value (if available). This is done by using the
FUSE_I_BTIME bit in fuse_inode->state to indicate availability, while using
fuse_inode->inval_mask & STATX_BTIME to indicate the state of the cache
itself (i.e. set if cache is invalid, and cleared if cache is valid).

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
diff d3045530 Wed Aug 09 16:45:05 MDT 2023 Miklos Szeredi <mszeredi@redhat.com> fuse: implement statx

Allow querying btime. When btime is requested in mask, then FUSE_STATX
request is sent. Otherwise keep using FUSE_GETATTR.

The userspace interface for statx matches that of the statx(2) API.
However there are limitations on how this interface is used:

- returned basic stats and btime are used, stx_attributes, etc. are
ignored

- always query basic stats and btime, regardless of what was requested

- requested sync type is ignored, the default is passed to the server

- if server returns with some attributes missing from the result_mask,
then no attributes will be cached

- btime is not cached yet (next patch will fix that)

For new inodes initialize fi->inval_mask to "all invalid", instead of "all
valid" as previously. Also only clear basic stats from inval_mask when
caching attributes. This will result in the caching logic not thinking
that btime is cached.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
diff 0d72b928 Mon Aug 07 13:38:33 MDT 2023 Jeff Layton <jlayton@kernel.org> fs: pass the request_mask to generic_fillattr

generic_fillattr just fills in the entire stat struct indiscriminately
today, copying data from the inode. There is at least one attribute
(STATX_CHANGE_COOKIE) that can have side effects when it is reported,
and we're looking at adding more with the addition of multigrain
timestamps.

Add a request_mask argument to generic_fillattr and have most callers
just pass in the value that is passed to getattr. Have other callers
(e.g. ksmbd) just pass in STATX_BASIC_STATS. Also move the setting of
STATX_CHANGE_COOKIE into generic_fillattr.

Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: "Paulo Alcantara (SUSE)" <pc@manguebit.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Message-Id: <20230807-mgctime-v7-2-d1dec143a704@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff facd6105 Thu Jan 19 16:55:04 MST 2023 Christian Brauner <brauner@kernel.org> fuse: fixes after adapting to new posix acl api

This cycle we ported all filesystems to the new posix acl api. While
looking at further simplifications in this area to remove the last
remnants of the generic dummy posix acl handlers we realized that we
regressed fuse daemons that don't set FUSE_POSIX_ACL but still make use
of posix acls.

With the change to a dedicated posix acl api interacting with posix acls
doesn't go through the old xattr codepaths anymore and instead only
relies the get acl and set acl inode operations.

Before this change fuse daemons that don't set FUSE_POSIX_ACL were able
to get and set posix acl albeit with two caveats. First, that posix acls
aren't cached. And second, that they aren't used for permission checking
in the vfs.

We regressed that use-case as we currently refuse to retrieve any posix
acls if they aren't enabled via FUSE_POSIX_ACL. So older fuse daemons
would see a change in behavior.

We can restore the old behavior in multiple ways. We could change the
new posix acl api and look for a dedicated xattr handler and if we find
one prefer that over the dedicated posix acl api. That would break the
consistency of the new posix acl api so we would very much prefer not to
do that.

We could introduce a new ACL_*_CACHE sentinel that would instruct the
vfs permission checking codepath to not call into the filesystem and
ignore acls.

But a more straightforward fix for v6.2 is to do the same thing that
Overlayfs does and give fuse a separate get acl method for permission
checking. Overlayfs uses this to express different needs for vfs
permission lookup and acl based retrieval via the regular system call
path as well. Let fuse do the same for now. This way fuse can continue
to refuse to retrieve posix acls for daemons that don't set
FUSE_POSXI_ACL for permission checking while allowing a fuse server to
retrieve it via the usual system calls.

In the future, we could extend the get acl inode operation to not just
pass a simple boolean to indicate rcu lookup but instead make it a flag
argument. Then in addition to passing the information that this is an
rcu lookup to the filesystem we could also introduce a flag that tells
the filesystem that this is a request from the vfs to use these acls for
permission checking. Then fuse could refuse the get acl request for
permission checking when the daemon doesn't have FUSE_POSIX_ACL set in
the same get acl method. This would also help Overlayfs and allow us to
remove the second method for it as well.

But since that change is more invasive as we need to update the get acl
inode operation for multiple filesystems we should not do this as a fix
for v6.2. Instead we will do this for the v6.3 merge window.

Fwiw, since posix acls are now always correctly translated in the new
posix acl api we could also allow them to be used for daemons without
FUSE_POSIX_ACL that are not mounted on the host. But this is behavioral
change and again if dones should be done for v6.3. For now, let's just
restore the original behavior.

A nice side-effect of this change is that for fuse daemons with and
without FUSE_POSIX_ACL the same code is used for posix acls in a
backwards compatible way. This also means we can remove the legacy xattr
handlers completely. We've also added comments to explain the expected
behavior for daemons without FUSE_POSIX_ACL into the code.

Fixes: 318e66856dde ("xattr: use posix acl api")
Signed-off-by: Seth Forshee (Digital Ocean) <sforshee@kernel.org>
Reviewed-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
diff facd6105 Thu Jan 19 16:55:04 MST 2023 Christian Brauner <brauner@kernel.org> fuse: fixes after adapting to new posix acl api

This cycle we ported all filesystems to the new posix acl api. While
looking at further simplifications in this area to remove the last
remnants of the generic dummy posix acl handlers we realized that we
regressed fuse daemons that don't set FUSE_POSIX_ACL but still make use
of posix acls.

With the change to a dedicated posix acl api interacting with posix acls
doesn't go through the old xattr codepaths anymore and instead only
relies the get acl and set acl inode operations.

Before this change fuse daemons that don't set FUSE_POSIX_ACL were able
to get and set posix acl albeit with two caveats. First, that posix acls
aren't cached. And second, that they aren't used for permission checking
in the vfs.

We regressed that use-case as we currently refuse to retrieve any posix
acls if they aren't enabled via FUSE_POSIX_ACL. So older fuse daemons
would see a change in behavior.

We can restore the old behavior in multiple ways. We could change the
new posix acl api and look for a dedicated xattr handler and if we find
one prefer that over the dedicated posix acl api. That would break the
consistency of the new posix acl api so we would very much prefer not to
do that.

We could introduce a new ACL_*_CACHE sentinel that would instruct the
vfs permission checking codepath to not call into the filesystem and
ignore acls.

But a more straightforward fix for v6.2 is to do the same thing that
Overlayfs does and give fuse a separate get acl method for permission
checking. Overlayfs uses this to express different needs for vfs
permission lookup and acl based retrieval via the regular system call
path as well. Let fuse do the same for now. This way fuse can continue
to refuse to retrieve posix acls for daemons that don't set
FUSE_POSXI_ACL for permission checking while allowing a fuse server to
retrieve it via the usual system calls.

In the future, we could extend the get acl inode operation to not just
pass a simple boolean to indicate rcu lookup but instead make it a flag
argument. Then in addition to passing the information that this is an
rcu lookup to the filesystem we could also introduce a flag that tells
the filesystem that this is a request from the vfs to use these acls for
permission checking. Then fuse could refuse the get acl request for
permission checking when the daemon doesn't have FUSE_POSIX_ACL set in
the same get acl method. This would also help Overlayfs and allow us to
remove the second method for it as well.

But since that change is more invasive as we need to update the get acl
inode operation for multiple filesystems we should not do this as a fix
for v6.2. Instead we will do this for the v6.3 merge window.

Fwiw, since posix acls are now always correctly translated in the new
posix acl api we could also allow them to be used for daemons without
FUSE_POSIX_ACL that are not mounted on the host. But this is behavioral
change and again if dones should be done for v6.3. For now, let's just
restore the original behavior.

A nice side-effect of this change is that for fuse daemons with and
without FUSE_POSIX_ACL the same code is used for posix acls in a
backwards compatible way. This also means we can remove the legacy xattr
handlers completely. We've also added comments to explain the expected
behavior for daemons without FUSE_POSIX_ACL into the code.

Fixes: 318e66856dde ("xattr: use posix acl api")
Signed-off-by: Seth Forshee (Digital Ocean) <sforshee@kernel.org>
Reviewed-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
diff 2fdbb8dd Fri Apr 22 07:48:53 MDT 2022 Miklos Szeredi <mszeredi@redhat.com> fuse: fix deadlock between atomic O_TRUNC and page invalidation

fuse_finish_open() will be called with FUSE_NOWRITE set in case of atomic
O_TRUNC open(), so commit 76224355db75 ("fuse: truncate pagecache on
atomic_o_trunc") replaced invalidate_inode_pages2() by truncate_pagecache()
in such a case to avoid the A-A deadlock. However, we found another A-B-B-A
deadlock related to the case above, which will cause the xfstests
generic/464 testcase hung in our virtio-fs test environment.

For example, consider two processes concurrently open one same file, one
with O_TRUNC and another without O_TRUNC. The deadlock case is described
below, if open(O_TRUNC) is already set_nowrite(acquired A), and is trying
to lock a page (acquiring B), open() could have held the page lock
(acquired B), and waiting on the page writeback (acquiring A). This would
lead to deadlocks.

open(O_TRUNC)
----------------------------------------------------------------
fuse_open_common
inode_lock [C acquire]
fuse_set_nowrite [A acquire]

fuse_finish_open
truncate_pagecache
lock_page [B acquire]
truncate_inode_page
unlock_page [B release]

fuse_release_nowrite [A release]
inode_unlock [C release]
----------------------------------------------------------------

open()
----------------------------------------------------------------
fuse_open_common
fuse_finish_open
invalidate_inode_pages2
lock_page [B acquire]
fuse_launder_page
fuse_wait_on_page_writeback [A acquire & release]
unlock_page [B release]
----------------------------------------------------------------

Besides this case, all calls of invalidate_inode_pages2() and
invalidate_inode_pages2_range() in fuse code also can deadlock with
open(O_TRUNC).

Fix by moving the truncate_pagecache() call outside the nowrite protected
region. The nowrite protection is only for delayed writeback
(writeback_cache) case, where inode lock does not protect against
truncation racing with writes on the server. Write syscalls racing with
page cache truncation still get the inode lock protection.

This patch also changes the order of filemap_invalidate_lock()
vs. fuse_set_nowrite() in fuse_open_common(). This new order matches the
order found in fuse_file_fallocate() and fuse_do_setattr().

Reported-by: Jiachen Zhang <zhangjiachen.jaycee@bytedance.com>
Tested-by: Jiachen Zhang <zhangjiachen.jaycee@bytedance.com>
Fixes: e4648309b85a ("fuse: truncate pending writes on O_TRUNC")
Cc: <stable@vger.kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
diff 2bf06b8e Wed Feb 09 13:21:56 MST 2022 Matthew Wilcox (Oracle) <willy@infradead.org> fuse: Convert from launder_page to launder_folio

Straightforward conversion although the helper functions still assume
a single page.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Tested-by: Mike Marshall <hubcap@omnibond.com> # orangefs
Tested-by: David Howells <dhowells@redhat.com> # afs
diff 5c791fe1 Fri Oct 22 09:03:01 MDT 2021 Miklos Szeredi <mszeredi@redhat.com> fuse: make sure reclaim doesn't write the inode

In writeback cache mode mtime/ctime updates are cached, and flushed to the
server using the ->write_inode() callback.

Closing the file will result in a dirty inode being immediately written,
but in other cases the inode can remain dirty after all references are
dropped. This result in the inode being written back from reclaim, which
can deadlock on a regular allocation while the request is being served.

The usual mechanisms (GFP_NOFS/PF_MEMALLOC*) don't work for FUSE, because
serving a request involves unrelated userspace process(es).

Instead do the same as for dirty pages: make sure the inode is written
before the last reference is gone.

- fallocate(2)/copy_file_range(2): these call file_update_time() or
file_modified(), so flush the inode before returning from the call

- unlink(2), link(2) and rename(2): these call fuse_update_ctime(), so
flush the ctime directly from this helper

Reported-by: chenguanyou <chenguanyou@xiaomi.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
diff 5c791fe1 Fri Oct 22 09:03:01 MDT 2021 Miklos Szeredi <mszeredi@redhat.com> fuse: make sure reclaim doesn't write the inode

In writeback cache mode mtime/ctime updates are cached, and flushed to the
server using the ->write_inode() callback.

Closing the file will result in a dirty inode being immediately written,
but in other cases the inode can remain dirty after all references are
dropped. This result in the inode being written back from reclaim, which
can deadlock on a regular allocation while the request is being served.

The usual mechanisms (GFP_NOFS/PF_MEMALLOC*) don't work for FUSE, because
serving a request involves unrelated userspace process(es).

Instead do the same as for dirty pages: make sure the inode is written
before the last reference is gone.

- fallocate(2)/copy_file_range(2): these call file_update_time() or
file_modified(), so flush the inode before returning from the call

- unlink(2), link(2) and rename(2): these call fuse_update_ctime(), so
flush the ctime directly from this helper

Reported-by: chenguanyou <chenguanyou@xiaomi.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
diff 5c791fe1 Fri Oct 22 09:03:01 MDT 2021 Miklos Szeredi <mszeredi@redhat.com> fuse: make sure reclaim doesn't write the inode

In writeback cache mode mtime/ctime updates are cached, and flushed to the
server using the ->write_inode() callback.

Closing the file will result in a dirty inode being immediately written,
but in other cases the inode can remain dirty after all references are
dropped. This result in the inode being written back from reclaim, which
can deadlock on a regular allocation while the request is being served.

The usual mechanisms (GFP_NOFS/PF_MEMALLOC*) don't work for FUSE, because
serving a request involves unrelated userspace process(es).

Instead do the same as for dirty pages: make sure the inode is written
before the last reference is gone.

- fallocate(2)/copy_file_range(2): these call file_update_time() or
file_modified(), so flush the inode before returning from the call

- unlink(2), link(2) and rename(2): these call fuse_update_ctime(), so
flush the ctime directly from this helper

Reported-by: chenguanyou <chenguanyou@xiaomi.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
diff 5c791fe1 Fri Oct 22 09:03:01 MDT 2021 Miklos Szeredi <mszeredi@redhat.com> fuse: make sure reclaim doesn't write the inode

In writeback cache mode mtime/ctime updates are cached, and flushed to the
server using the ->write_inode() callback.

Closing the file will result in a dirty inode being immediately written,
but in other cases the inode can remain dirty after all references are
dropped. This result in the inode being written back from reclaim, which
can deadlock on a regular allocation while the request is being served.

The usual mechanisms (GFP_NOFS/PF_MEMALLOC*) don't work for FUSE, because
serving a request involves unrelated userspace process(es).

Instead do the same as for dirty pages: make sure the inode is written
before the last reference is gone.

- fallocate(2)/copy_file_range(2): these call file_update_time() or
file_modified(), so flush the inode before returning from the call

- unlink(2), link(2) and rename(2): these call fuse_update_ctime(), so
flush the ctime directly from this helper

Reported-by: chenguanyou <chenguanyou@xiaomi.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
diff 5c791fe1 Fri Oct 22 09:03:01 MDT 2021 Miklos Szeredi <mszeredi@redhat.com> fuse: make sure reclaim doesn't write the inode

In writeback cache mode mtime/ctime updates are cached, and flushed to the
server using the ->write_inode() callback.

Closing the file will result in a dirty inode being immediately written,
but in other cases the inode can remain dirty after all references are
dropped. This result in the inode being written back from reclaim, which
can deadlock on a regular allocation while the request is being served.

The usual mechanisms (GFP_NOFS/PF_MEMALLOC*) don't work for FUSE, because
serving a request involves unrelated userspace process(es).

Instead do the same as for dirty pages: make sure the inode is written
before the last reference is gone.

- fallocate(2)/copy_file_range(2): these call file_update_time() or
file_modified(), so flush the inode before returning from the call

- unlink(2), link(2) and rename(2): these call fuse_update_ctime(), so
flush the ctime directly from this helper

Reported-by: chenguanyou <chenguanyou@xiaomi.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
/linux-master/fs/gfs2/
H A Dinode.cdiff 2d8d7990 Sat Oct 21 12:51:13 MDT 2023 Andreas Gruenbacher <agruenba@redhat.com> gfs2: setattr_chown: Add missing initialization

Add a missing initialization of variable ap in setattr_chown().
Without, chown() may be able to bypass quotas.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
diff 0d72b928 Mon Aug 07 13:38:33 MDT 2023 Jeff Layton <jlayton@kernel.org> fs: pass the request_mask to generic_fillattr

generic_fillattr just fills in the entire stat struct indiscriminately
today, copying data from the inode. There is at least one attribute
(STATX_CHANGE_COOKIE) that can have side effects when it is reported,
and we're looking at adding more with the addition of multigrain
timestamps.

Add a request_mask argument to generic_fillattr and have most callers
just pass in the value that is passed to getattr. Have other callers
(e.g. ksmbd) just pass in STATX_BASIC_STATS. Also move the setting of
STATX_CHANGE_COOKIE into generic_fillattr.

Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: "Paulo Alcantara (SUSE)" <pc@manguebit.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Message-Id: <20230807-mgctime-v7-2-d1dec143a704@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff 2d084780 Tue Mar 14 07:18:28 MDT 2023 Andrew Price <anprice@redhat.com> gfs2: Remove ghs[] from gfs2_link

Replace the 2-item array with two variables for readability.

Signed-off-by: Andrew Price <anprice@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
diff 2d084780 Tue Mar 14 07:18:28 MDT 2023 Andrew Price <anprice@redhat.com> gfs2: Remove ghs[] from gfs2_link

Replace the 2-item array with two variables for readability.

Signed-off-by: Andrew Price <anprice@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
diff 8dc14966 Tue Mar 14 07:18:27 MDT 2023 Andrew Price <anprice@redhat.com> gfs2: Remove duplicate i_nlink check from gfs2_link()

The duplication is:

struct gfs2_inode *ip = GFS2_I(inode);
[...]
error = -ENOENT;
if (inode->i_nlink == 0)
goto out_gunlock;
[...]
error = -EINVAL;
if (!ip->i_inode.i_nlink)
goto out_gunlock;

The second check is removed. ENOENT is the correct error code for
attempts to link a deleted inode (ref: link(2)).

If we support O_TMPFILE in future the check will need to be updated with
an exception for inodes flagged I_LINKABLE so sorting out this
duplication now will make it a slightly cleaner change.

Signed-off-by: Andrew Price <anprice@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
diff 2ec750a0 Sat Dec 03 16:51:55 MST 2022 Andreas Gruenbacher <agruenba@redhat.com> gfs2: Add gfs2_inode_lookup comment

Add comment on when and why gfs2_cancel_delete_work() needs to be
skipped in gfs2_inode_lookup().

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
diff 763766c0 Wed Sep 29 13:42:38 MDT 2021 Bob Peterson <rpeterso@redhat.com> gfs2: dequeue iopen holder in gfs2_inode_lookup error

Before this patch, if function gfs2_inode_lookup encountered an error
after it had locked the iopen glock, it never unlocked it, relying on
the evict code to do the cleanup. The evict code then took the
inode glock while holding the iopen glock, which violates the locking
order. For example,

(1) node A does a gfs2_inode_lookup that fails, leaving the iopen glock
locked.

(2) node B calls delete_work_func -> gfs2_lookup_by_inum ->
gfs2_inode_lookup. It locks the inode glock and blocks trying to
lock the iopen glock, which is held by node A.

(3) node A eventually calls gfs2_evict_inode -> evict_should_delete.
It blocks trying to lock the inode glock, which is now held by
node B.

This patch introduces error handling to function gfs2_inode_lookup
so it properly dequeues held iopen glocks on errors.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 2fba46a0 Wed Feb 26 23:47:53 MST 2020 Bob Peterson <rpeterso@redhat.com> gfs2: Change inode qa_data to allow multiple users

Before this patch, multiple users called gfs2_qa_alloc which allocated
a qadata structure to the inode, if quotas are turned on. Later, in
file close or evict, the structure was deleted with gfs2_qa_delete.
But there can be several competing processes who need access to the
structure. There were races between file close (release) and the others.
Thus, a release could delete the structure out from under a process
that relied upon its existence. For example, chown.

This patch changes the management of the qadata structures to be
a get/put scheme. Function gfs2_qa_alloc has been changed to gfs2_qa_get
and if the structure is allocated, the count essentially starts out at
1. Function gfs2_qa_delete has been renamed to gfs2_qa_put, and the
last guy to decrement the count to 0 frees the memory.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
/linux-master/fs/hfs/
H A Dinode.cdiff 2cb1e089 Mon May 22 07:50:15 MDT 2023 David Howells <dhowells@redhat.com> splice: Use filemap_splice_read() instead of generic_file_splice_read()

Replace pointers to generic_file_splice_read() with calls to
filemap_splice_read().

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: David Hildenbrand <david@redhat.com>
cc: John Hubbard <jhubbard@nvidia.com>
cc: linux-mm@kvack.org
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20230522135018.2742245-29-dhowells@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff 2c69e205 Fri Apr 29 08:40:40 MDT 2022 Matthew Wilcox (Oracle) <willy@infradead.org> fs: Convert block_read_full_page() to block_read_full_folio()

This function is NOT converted to handle large folios, so include
an assert that the filesystem isn't passing one in. Otherwise, use
the folio functions instead of the page functions, where they exist.
Convert all filesystems which use block_read_full_page().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 4ddfc3dc Wed Jun 20 01:47:26 MDT 2018 Arnd Bergmann <arnd@arndb.de> hfs/hfsplus: use 64-bit inode timestamps

The interpretation of on-disk timestamps in HFS and HFS+ differs
between 32-bit and 64-bit kernels at the moment. Use 64-bit timestamps
consistently so apply the current 64-bit behavior everyhere.

According to the official documentation for HFS+ [1], inode timestamps
are supposed to cover the time range from 1904 to 2040 as originally
used in classic MacOS.

The traditional Linux usage is to convert the timestamps into an unsigned
32-bit number based on the Unix epoch and from there to a time_t. On
32-bit systems, that wraps the time from 2038 to 1902, so the last
two years of the valid time range become garbled. On 64-bit systems,
all times before 1970 get turned into timestamps between 2038 and 2106,
which is more convenient but also different from the documented behavior.

Looking at the Darwin sources [2], it seems that MacOS is inconsistent in
yet another way: all timestamps are wrapped around to a 32-bit unsigned
number when written to the disk, but when read back, all numeric values
lower than 2082844800U are assumed to be invalid, so we cannot represent
the times before 1970 or the times after 2040.

While all implementations seem to agree on the interpretation of values
between 1970 and 2038, they often differ on the exact range they support
when reading back values outside of the common range:

MacOS (traditional): 1904-2040
Apple Documentation: 1904-2040
MacOS X source comments: 1970-2040
MacOS X source code: 1970-2038
32-bit Linux: 1902-2038
64-bit Linux: 1970-2106
hfsfuse: 1970-2040
hfsutils (32 bit, old libc) 1902-2038
hfsutils (32 bit, new libc) 1970-2106
hfsutils (64 bit) 1904-2040
hfsplus-utils 1904-2040
hfsexplorer 1904-2040
7-zip 1904-2040

Out of the above, the range from 1970 to 2106 seems to be the most useful,
as it allows using HFS and HFS+ beyond year 2038, and this matches the
behavior that most users would see today on Linux, as few people run
32-bit kernels any more.

Link: [1] https://developer.apple.com/library/archive/technotes/tn/tn1150.html
Link: [2] https://opensource.apple.com/source/hfs/hfs-407.30.1/core/MacOSStubs.c.auto.html
Link: https://lore.kernel.org/lkml/20180711224625.airwna6gzyatoowe@eaf/
Suggested-by: "Ernesto A. Fernández" <ernesto.mnd.fernandez@gmail.com>
Reviewed-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Reviewed-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
v3: revert back to 1970-2106 time range
fix bugs found in review
merge both patches into one
drop cc:stable tag
v2: treat pre-1970 dates as invalid following MacOS X behavior,
reword and expand changelog text
diff 4ddfc3dc Wed Jun 20 01:47:26 MDT 2018 Arnd Bergmann <arnd@arndb.de> hfs/hfsplus: use 64-bit inode timestamps

The interpretation of on-disk timestamps in HFS and HFS+ differs
between 32-bit and 64-bit kernels at the moment. Use 64-bit timestamps
consistently so apply the current 64-bit behavior everyhere.

According to the official documentation for HFS+ [1], inode timestamps
are supposed to cover the time range from 1904 to 2040 as originally
used in classic MacOS.

The traditional Linux usage is to convert the timestamps into an unsigned
32-bit number based on the Unix epoch and from there to a time_t. On
32-bit systems, that wraps the time from 2038 to 1902, so the last
two years of the valid time range become garbled. On 64-bit systems,
all times before 1970 get turned into timestamps between 2038 and 2106,
which is more convenient but also different from the documented behavior.

Looking at the Darwin sources [2], it seems that MacOS is inconsistent in
yet another way: all timestamps are wrapped around to a 32-bit unsigned
number when written to the disk, but when read back, all numeric values
lower than 2082844800U are assumed to be invalid, so we cannot represent
the times before 1970 or the times after 2040.

While all implementations seem to agree on the interpretation of values
between 1970 and 2038, they often differ on the exact range they support
when reading back values outside of the common range:

MacOS (traditional): 1904-2040
Apple Documentation: 1904-2040
MacOS X source comments: 1970-2040
MacOS X source code: 1970-2038
32-bit Linux: 1902-2038
64-bit Linux: 1970-2106
hfsfuse: 1970-2040
hfsutils (32 bit, old libc) 1902-2038
hfsutils (32 bit, new libc) 1970-2106
hfsutils (64 bit) 1904-2040
hfsplus-utils 1904-2040
hfsexplorer 1904-2040
7-zip 1904-2040

Out of the above, the range from 1970 to 2106 seems to be the most useful,
as it allows using HFS and HFS+ beyond year 2038, and this matches the
behavior that most users would see today on Linux, as few people run
32-bit kernels any more.

Link: [1] https://developer.apple.com/library/archive/technotes/tn/tn1150.html
Link: [2] https://opensource.apple.com/source/hfs/hfs-407.30.1/core/MacOSStubs.c.auto.html
Link: https://lore.kernel.org/lkml/20180711224625.airwna6gzyatoowe@eaf/
Suggested-by: "Ernesto A. Fernández" <ernesto.mnd.fernandez@gmail.com>
Reviewed-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Reviewed-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
v3: revert back to 1970-2106 time range
fix bugs found in review
merge both patches into one
drop cc:stable tag
v2: treat pre-1970 dates as invalid following MacOS X behavior,
reword and expand changelog text
diff 0e5c56fd Mon Apr 30 17:52:18 MDT 2018 Al Viro <viro@zeniv.linux.org.uk> hfs: don't allow mounting over .../rsrc

That's one case when unlink() destroys a subtree, thanks to "resource
fork" idiocy. We might forcibly evict that shit on unlink(2), but
for now let's just disallow overmounting; as it is, anything that
plays games with those would leak mounts.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff 5b825c3a Thu Feb 02 09:54:15 MST 2017 Ingo Molnar <mingo@kernel.org> sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h>

Add #include <linux/cred.h> dependencies to all .c files rely on sched.h
doing that for them.

Note that even if the count where we need to add extra headers seems high,
it's still a net win, because <linux/sched.h> is included in over
2,200 files ...

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff 2b0143b5 Tue Mar 17 16:25:59 MDT 2015 David Howells <dhowells@redhat.com> VFS: normal filesystems (and lustre): d_inode() annotations

that's the bulk of filesystem drivers dealing with inodes of their own

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff 4527440d Thu Jul 12 08:28:47 MDT 2012 Artem Bityutskiy <artem.bityutskiy@linux.intel.com> hfs: simplify a bit checking for R/O

We have the following pattern in 2 places in HFS

if (!RDONLY)
hfs_mdb_commit();

This patch pushes the RDONLY check down to 'hfs_mdb_commit()'. This will
make the following patches a bit simpler.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
/linux-master/fs/hfsplus/
H A Dinode.cdiff 0d72b928 Mon Aug 07 13:38:33 MDT 2023 Jeff Layton <jlayton@kernel.org> fs: pass the request_mask to generic_fillattr

generic_fillattr just fills in the entire stat struct indiscriminately
today, copying data from the inode. There is at least one attribute
(STATX_CHANGE_COOKIE) that can have side effects when it is reported,
and we're looking at adding more with the addition of multigrain
timestamps.

Add a request_mask argument to generic_fillattr and have most callers
just pass in the value that is passed to getattr. Have other callers
(e.g. ksmbd) just pass in STATX_BASIC_STATS. Also move the setting of
STATX_CHANGE_COOKIE into generic_fillattr.

Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: "Paulo Alcantara (SUSE)" <pc@manguebit.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Message-Id: <20230807-mgctime-v7-2-d1dec143a704@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff 2cb1e089 Mon May 22 07:50:15 MDT 2023 David Howells <dhowells@redhat.com> splice: Use filemap_splice_read() instead of generic_file_splice_read()

Replace pointers to generic_file_splice_read() with calls to
filemap_splice_read().

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: David Hildenbrand <david@redhat.com>
cc: John Hubbard <jhubbard@nvidia.com>
cc: linux-mm@kvack.org
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20230522135018.2742245-29-dhowells@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff 2c69e205 Fri Apr 29 08:40:40 MDT 2022 Matthew Wilcox (Oracle) <willy@infradead.org> fs: Convert block_read_full_page() to block_read_full_folio()

This function is NOT converted to handle large folios, so include
an assert that the filesystem isn't passing one in. Otherwise, use
the folio functions instead of the page functions, where they exist.
Convert all filesystems which use block_read_full_page().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 4ddfc3dc Wed Jun 20 01:47:26 MDT 2018 Arnd Bergmann <arnd@arndb.de> hfs/hfsplus: use 64-bit inode timestamps

The interpretation of on-disk timestamps in HFS and HFS+ differs
between 32-bit and 64-bit kernels at the moment. Use 64-bit timestamps
consistently so apply the current 64-bit behavior everyhere.

According to the official documentation for HFS+ [1], inode timestamps
are supposed to cover the time range from 1904 to 2040 as originally
used in classic MacOS.

The traditional Linux usage is to convert the timestamps into an unsigned
32-bit number based on the Unix epoch and from there to a time_t. On
32-bit systems, that wraps the time from 2038 to 1902, so the last
two years of the valid time range become garbled. On 64-bit systems,
all times before 1970 get turned into timestamps between 2038 and 2106,
which is more convenient but also different from the documented behavior.

Looking at the Darwin sources [2], it seems that MacOS is inconsistent in
yet another way: all timestamps are wrapped around to a 32-bit unsigned
number when written to the disk, but when read back, all numeric values
lower than 2082844800U are assumed to be invalid, so we cannot represent
the times before 1970 or the times after 2040.

While all implementations seem to agree on the interpretation of values
between 1970 and 2038, they often differ on the exact range they support
when reading back values outside of the common range:

MacOS (traditional): 1904-2040
Apple Documentation: 1904-2040
MacOS X source comments: 1970-2040
MacOS X source code: 1970-2038
32-bit Linux: 1902-2038
64-bit Linux: 1970-2106
hfsfuse: 1970-2040
hfsutils (32 bit, old libc) 1902-2038
hfsutils (32 bit, new libc) 1970-2106
hfsutils (64 bit) 1904-2040
hfsplus-utils 1904-2040
hfsexplorer 1904-2040
7-zip 1904-2040

Out of the above, the range from 1970 to 2106 seems to be the most useful,
as it allows using HFS and HFS+ beyond year 2038, and this matches the
behavior that most users would see today on Linux, as few people run
32-bit kernels any more.

Link: [1] https://developer.apple.com/library/archive/technotes/tn/tn1150.html
Link: [2] https://opensource.apple.com/source/hfs/hfs-407.30.1/core/MacOSStubs.c.auto.html
Link: https://lore.kernel.org/lkml/20180711224625.airwna6gzyatoowe@eaf/
Suggested-by: "Ernesto A. Fernández" <ernesto.mnd.fernandez@gmail.com>
Reviewed-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Reviewed-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
v3: revert back to 1970-2106 time range
fix bugs found in review
merge both patches into one
drop cc:stable tag
v2: treat pre-1970 dates as invalid following MacOS X behavior,
reword and expand changelog text
diff 4ddfc3dc Wed Jun 20 01:47:26 MDT 2018 Arnd Bergmann <arnd@arndb.de> hfs/hfsplus: use 64-bit inode timestamps

The interpretation of on-disk timestamps in HFS and HFS+ differs
between 32-bit and 64-bit kernels at the moment. Use 64-bit timestamps
consistently so apply the current 64-bit behavior everyhere.

According to the official documentation for HFS+ [1], inode timestamps
are supposed to cover the time range from 1904 to 2040 as originally
used in classic MacOS.

The traditional Linux usage is to convert the timestamps into an unsigned
32-bit number based on the Unix epoch and from there to a time_t. On
32-bit systems, that wraps the time from 2038 to 1902, so the last
two years of the valid time range become garbled. On 64-bit systems,
all times before 1970 get turned into timestamps between 2038 and 2106,
which is more convenient but also different from the documented behavior.

Looking at the Darwin sources [2], it seems that MacOS is inconsistent in
yet another way: all timestamps are wrapped around to a 32-bit unsigned
number when written to the disk, but when read back, all numeric values
lower than 2082844800U are assumed to be invalid, so we cannot represent
the times before 1970 or the times after 2040.

While all implementations seem to agree on the interpretation of values
between 1970 and 2038, they often differ on the exact range they support
when reading back values outside of the common range:

MacOS (traditional): 1904-2040
Apple Documentation: 1904-2040
MacOS X source comments: 1970-2040
MacOS X source code: 1970-2038
32-bit Linux: 1902-2038
64-bit Linux: 1970-2106
hfsfuse: 1970-2040
hfsutils (32 bit, old libc) 1902-2038
hfsutils (32 bit, new libc) 1970-2106
hfsutils (64 bit) 1904-2040
hfsplus-utils 1904-2040
hfsexplorer 1904-2040
7-zip 1904-2040

Out of the above, the range from 1970 to 2106 seems to be the most useful,
as it allows using HFS and HFS+ beyond year 2038, and this matches the
behavior that most users would see today on Linux, as few people run
32-bit kernels any more.

Link: [1] https://developer.apple.com/library/archive/technotes/tn/tn1150.html
Link: [2] https://opensource.apple.com/source/hfs/hfs-407.30.1/core/MacOSStubs.c.auto.html
Link: https://lore.kernel.org/lkml/20180711224625.airwna6gzyatoowe@eaf/
Suggested-by: "Ernesto A. Fernández" <ernesto.mnd.fernandez@gmail.com>
Reviewed-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Reviewed-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
v3: revert back to 1970-2106 time range
fix bugs found in review
merge both patches into one
drop cc:stable tag
v2: treat pre-1970 dates as invalid following MacOS X behavior,
reword and expand changelog text
diff b2441318 Wed Nov 01 08:07:57 MDT 2017 Greg Kroah-Hartman <gregkh@linuxfoundation.org> License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff b2441318 Wed Nov 01 08:07:57 MDT 2017 Greg Kroah-Hartman <gregkh@linuxfoundation.org> License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff 5b825c3a Thu Feb 02 09:54:15 MST 2017 Ingo Molnar <mingo@kernel.org> sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h>

Add #include <linux/cred.h> dependencies to all .c files rely on sched.h
doing that for them.

Note that even if the count where we need to add extra headers seems high,
it's still a net win, because <linux/sched.h> is included in over
2,200 files ...

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
/linux-master/fs/hostfs/
H A Dhostfs_kern.cdiff 74ce793b Mon Jun 12 13:14:25 MDT 2023 Mickaël Salaün <mic@digikod.net> hostfs: Fix ephemeral inodes

hostfs creates a new inode for each opened or created file, which
created useless inode allocations and forbade identifying a host file
with a kernel inode.

Fix this uncommon filesystem behavior by tying kernel inodes to host
file's inode and device IDs. Even if the host filesystem inodes may be
recycled, this cannot happen while a file referencing it is opened,
which is the case with hostfs. It should be noted that hostfs inode IDs
may not be unique for the same hostfs superblock because multiple host's
(backed) superblocks may be used.

Delete inodes when dropping them to force backed host's file descriptors
closing.

This enables to entirely remove ARCH_EPHEMERAL_INODES, and then makes
Landlock fully supported by UML. This is very useful for testing
changes.

These changes also factor out and simplify some helpers thanks to the
new hostfs_inode_update() and the hostfs_iget() revamp: read_name(),
hostfs_create(), hostfs_lookup(), hostfs_mknod(), and
hostfs_fill_sb_common().

A following commit with new Landlock tests check this new hostfs inode
consistency.

Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Richard Weinberger <richard@nod.at>
Link: https://lore.kernel.org/r/20230612191430.339153-2-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>
diff 2cb1e089 Mon May 22 07:50:15 MDT 2023 David Howells <dhowells@redhat.com> splice: Use filemap_splice_read() instead of generic_file_splice_read()

Replace pointers to generic_file_splice_read() with calls to
filemap_splice_read().

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: David Hildenbrand <david@redhat.com>
cc: John Hubbard <jhubbard@nvidia.com>
cc: linux-mm@kvack.org
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20230522135018.2742245-29-dhowells@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff e0820368 Thu Oct 13 10:17:00 MDT 2022 Fabio M. De Francesco <fmdefrancesco@gmail.com> hostfs: Replace kmap() with kmap_local_page()

The use of kmap() is being deprecated in favor of kmap_local_page().

There are two main problems with kmap(): (1) It comes with an overhead as
the mapping space is restricted and protected by a global lock for
synchronization and (2) it also requires global TLB invalidation when the
kmap’s pool wraps and it might block when the mapping space is fully
utilized until a slot becomes available.

With kmap_local_page() the mappings are per thread, CPU local, can take
page faults, and can be called from any context (including interrupts).
It is faster than kmap() in kernels with HIGHMEM enabled. Furthermore,
the tasks can be preempted and, when they are scheduled to run again, the
kernel virtual addresses are restored and still valid.

Therefore, replace kmap() with kmap_local_page() in hostfs_kern.c, it
being the only file with kmap() call sites currently left in fs/hostfs.

Cc: "Venkataramanan, Anirudh" <anirudh.venkataramanan@intel.com>
Suggested-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
diff 7f6c411c Thu Mar 25 12:12:34 MDT 2021 Al Viro <viro@zeniv.linux.org.uk> hostfs: fix memory handling in follow_link()

1) argument should not be freed in any case - the caller already has
it as ->s_fs_info (and uses it a lot afterwards)
2) allocate readlink buffer with kmalloc() - the caller has no way
to tell if it's got that (on absolute symlink) or a result of
kasprintf(). Sure, for SLAB and SLUB kfree() works on results of
kmem_cache_alloc(), but that's not documented anywhere, might change
in the future *and* is already not true for SLOB.

Fixes: 52b209f7b848 ("get rid of hostfs_read_inode()")
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 2e2cbaf9 Wed Dec 09 16:38:24 MST 2020 Al Viro <viro@zeniv.linux.org.uk> fix hostfs_open() use of ->f_path.dentry

this is one of the cases where we need to use d_real() - we are
using more than the name of dentry here. ->d_sb is used as well,
so in case of hostfs being used as a layer we get the wrong
superblock.

Reported-by: Johannes Berg <johannes@sipsolutions.net>
Tested-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff 2b0143b5 Tue Mar 17 16:25:59 MDT 2015 David Howells <dhowells@redhat.com> VFS: normal filesystems (and lustre): d_inode() annotations

that's the bulk of filesystem drivers dealing with inodes of their own

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff 2ad2dca6 Sun Mar 01 16:10:25 MST 2015 Richard Weinberger <richard@nod.at> hostfs: Handle bogus st.mode

Make sure that we return EIO if one passes an invalid st.mode
into hostfs.

Signed-off-by: Richard Weinberger <richard@nod.at>
diff 9a423bb6 Wed Jul 23 07:15:35 MDT 2014 Miklos Szeredi <mszeredi@suse.cz> hostfs: support rename flags

Support RENAME_NOREPLACE and RENAME_EXCHANGE flags on hostfs if the
underlying filesystem supports it.

Since renameat2(2) is not yet in any libc, use syscall(2) to invoke the
renameat2 syscall.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff 9a423bb6 Wed Jul 23 07:15:35 MDT 2014 Miklos Szeredi <mszeredi@suse.cz> hostfs: support rename flags

Support RENAME_NOREPLACE and RENAME_EXCHANGE flags on hostfs if the
underlying filesystem supports it.

Since renameat2(2) is not yet in any libc, use syscall(2) to invoke the
renameat2 syscall.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Richard Weinberger <richard@nod.at>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
/linux-master/fs/hpfs/
H A Dinode.cdiff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff b2441318 Wed Nov 01 08:07:57 MDT 2017 Greg Kroah-Hartman <gregkh@linuxfoundation.org> License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff b2441318 Wed Nov 01 08:07:57 MDT 2017 Greg Kroah-Hartman <gregkh@linuxfoundation.org> License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff 2b0143b5 Tue Mar 17 16:25:59 MDT 2015 David Howells <dhowells@redhat.com> VFS: normal filesystems (and lustre): d_inode() annotations

that's the bulk of filesystem drivers dealing with inodes of their own

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff 48f10e8c Sun May 08 12:44:00 MDT 2011 Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz> HPFS: Restrict uid and gid to 16-bit values

Restrict uid and gid to 16-bit values.

HPFS stores only 2 bytes in the EAs.

Signed-off-by: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff 5a0e3ad6 Wed Mar 24 02:04:11 MDT 2010 Tejun Heo <tj@kernel.org> include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.

2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).

* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
diff 5a0e3ad6 Wed Mar 24 02:04:11 MDT 2010 Tejun Heo <tj@kernel.org> include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.

2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).

* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
diff 2ef10312 Sat Dec 24 12:31:53 MST 2005 Al Viro <viro@ftp.linux.org.uk> [PATCH] hpfs endianness annotations

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
/linux-master/fs/hugetlbfs/
H A Dinode.cdiff ae62bcb5 Mon Oct 23 08:30:49 MDT 2023 Amir Goldstein <amir73il@gmail.com> fs: report f_fsid from s_dev for "simple" filesystems

There are many "simple" filesystems (*) that report null f_fsid in
statfs(2). Those "simple" filesystems report sb->s_dev as the st_dev
field of the stat syscalls for all inodes of the filesystem (**).

In order to enable fanotify reporting of events with fsid on those
"simple" filesystems, report the sb->s_dev number in f_fsid field of
statfs(2).

(*) For most of the "simple" filesystem refered to in this commit, the
->statfs() operation is simple_statfs(). Some of those fs assign the
simple_statfs() method directly in their ->s_op struct and some assign it
indirectly via a call to simple_fill_super() or to pseudo_fs_fill_super()
with either custom or "simple" s_op.
We also make the same change to efivarfs and hugetlbfs, although they do
not use simple_statfs(), because they use the simple_* inode opreations
(e.g. simple_lookup()).

(**) For most of the "simple" filesystems, the ->getattr() method is not
assigned, so stat() is implemented by generic_fillattr(). A few "simple"
filesystem use the simple_getattr() method which also calls
generic_fillattr() to fill most of the stat struct.

The two exceptions are procfs and 9p. procfs implements several different
->getattr() methods, but they all end up calling generic_fillattr() to
fill the st_dev field from sb->s_dev.

9p has more complicated ->getattr() methods, but they too, end up calling
generic_fillattr() to fill the st_dev field from sb->s_dev.

Note that 9p and kernfs also call simple_statfs() from custom ->statfs()
methods which already fill the f_fsid field, but v9fs_statfs() calls
simple_statfs() only in case f_fsid was not filled and kenrfs_statfs()
overwrites f_fsid after calling simple_statfs().

Link: https://lore.kernel.org/r/20230919094820.g5bwharbmy2dq46w@quack3/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231023143049.2944970-1-amir73il@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff ae62bcb5 Mon Oct 23 08:30:49 MDT 2023 Amir Goldstein <amir73il@gmail.com> fs: report f_fsid from s_dev for "simple" filesystems

There are many "simple" filesystems (*) that report null f_fsid in
statfs(2). Those "simple" filesystems report sb->s_dev as the st_dev
field of the stat syscalls for all inodes of the filesystem (**).

In order to enable fanotify reporting of events with fsid on those
"simple" filesystems, report the sb->s_dev number in f_fsid field of
statfs(2).

(*) For most of the "simple" filesystem refered to in this commit, the
->statfs() operation is simple_statfs(). Some of those fs assign the
simple_statfs() method directly in their ->s_op struct and some assign it
indirectly via a call to simple_fill_super() or to pseudo_fs_fill_super()
with either custom or "simple" s_op.
We also make the same change to efivarfs and hugetlbfs, although they do
not use simple_statfs(), because they use the simple_* inode opreations
(e.g. simple_lookup()).

(**) For most of the "simple" filesystems, the ->getattr() method is not
assigned, so stat() is implemented by generic_fillattr(). A few "simple"
filesystem use the simple_getattr() method which also calls
generic_fillattr() to fill most of the stat struct.

The two exceptions are procfs and 9p. procfs implements several different
->getattr() methods, but they all end up calling generic_fillattr() to
fill the st_dev field from sb->s_dev.

9p has more complicated ->getattr() methods, but they too, end up calling
generic_fillattr() to fill the st_dev field from sb->s_dev.

Note that 9p and kernfs also call simple_statfs() from custom ->statfs()
methods which already fill the f_fsid field, but v9fs_statfs() calls
simple_statfs() only in case f_fsid was not filled and kenrfs_statfs()
overwrites f_fsid after calling simple_statfs().

Link: https://lore.kernel.org/r/20230919094820.g5bwharbmy2dq46w@quack3/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231023143049.2944970-1-amir73il@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff a08c7193 Tue Sep 26 01:20:17 MDT 2023 Sidhartha Kumar <sidhartha.kumar@oracle.com> mm/filemap: remove hugetlb special casing in filemap.c

Remove special cased hugetlb handling code within the page cache by
changing the granularity of ->index to the base page size rather than the
huge page size. The motivation of this patch is to reduce complexity
within the filemap code while also increasing performance by removing
branches that are evaluated on every page cache lookup.

To support the change in index, new wrappers for hugetlb page cache
interactions are added. These wrappers perform the conversion to a linear
index which is now expected by the page cache for huge pages.

========================= PERFORMANCE ======================================

Perf was used to check the performance differences after the patch.
Overall the performance is similar to mainline with a very small larger
overhead that occurs in __filemap_add_folio() and
hugetlb_add_to_page_cache(). This is because of the larger overhead that
occurs in xa_load() and xa_store() as the xarray is now using more entries
to store hugetlb folios in the page cache.

Timing

aarch64
2MB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-1 hugepages]# time fallocate -l 700GB test.txt
real 1m49.568s
user 0m0.000s
sys 1m49.461s

6.5-rc3:
[root]# time fallocate -l 700GB test.txt
real 1m47.495s
user 0m0.000s
sys 1m47.370s
1GB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
real 1m47.024s
user 0m0.000s
sys 1m46.921s

6.5-rc3:
[root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
real 1m44.551s
user 0m0.000s
sys 1m44.438s

x86
2MB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-2 hugepages]# time fallocate -l 100GB test.txt
real 0m22.383s
user 0m0.000s
sys 0m22.255s

6.5-rc3:
[opc@sidhakum-ol9-2 hugepages]$ time sudo fallocate -l 100GB /dev/hugepages/test.txt
real 0m22.735s
user 0m0.038s
sys 0m22.567s

1GB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-2 hugepages1GB]# time fallocate -l 100GB test.txt
real 0m25.786s
user 0m0.001s
sys 0m25.589s

6.5-rc3:
[root@sidhakum-ol9-2 hugepages1G]# time fallocate -l 100GB test.txt
real 0m33.454s
user 0m0.001s
sys 0m33.193s

aarch64:
workload - fallocate a 700GB file backed by huge pages

6.5-rc3 + this patch:
2MB Page Size:
--100.00%--__arm64_sys_fallocate
ksys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
|--95.04%--__pi_clear_page
|
|--3.57%--clear_huge_page
| |
| |--2.63%--rcu_all_qs
| |
| --0.91%--__cond_resched
|
--0.67%--__cond_resched
0.17% 0.00% 0 fallocate [kernel.vmlinux] [k] hugetlb_add_to_page_cache
0.14% 0.10% 11 fallocate [kernel.vmlinux] [k] __filemap_add_folio

6.5-rc3
2MB Page Size:
--100.00%--__arm64_sys_fallocate
ksys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
|--94.91%--__pi_clear_page
|
|--4.11%--clear_huge_page
| |
| |--3.00%--rcu_all_qs
| |
| --1.10%--__cond_resched
|
--0.59%--__cond_resched
0.08% 0.01% 1 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache
0.05% 0.03% 3 fallocate [kernel.kallsyms] [k] __filemap_add_folio

x86
workload - fallocate a 100GB file backed by huge pages

6.5-rc3 + this patch:
2MB Page Size:
hugetlbfs_fallocate
|
--99.57%--clear_huge_page
|
--98.47%--clear_page_erms
|
--0.53%--asm_sysvec_apic_timer_interrupt

0.04% 0.04% 1 fallocate [kernel.kallsyms] [k] xa_load
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] __filemap_add_folio
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] xas_store

6.5-rc3
2MB Page Size:
--99.93%--__x64_sys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
--99.38%--clear_huge_page
|
|--98.40%--clear_page_erms
|
--0.59%--__cond_resched
0.03% 0.03% 1 fallocate [kernel.kallsyms] [k] __filemap_add_folio

========================= TESTING ======================================

This patch passes libhugetlbfs tests and LTP hugetlb tests

********** TEST SUMMARY
* 2M
* 32-bit 64-bit
* Total testcases: 110 113
* Skipped: 0 0
* PASS: 107 113
* FAIL: 0 0
* Killed by signal: 3 0
* Bad configuration: 0 0
* Expected FAIL: 0 0
* Unexpected PASS: 0 0
* Test not present: 0 0
* Strange test result: 0 0
**********

Done executing testcases.
LTP Version: 20220527-178-g2761a81c4

page migration was also tested using Mike Kravetz's test program.[8]

[dan.carpenter@linaro.org: fix an NULL vs IS_ERR() bug]
Link: https://lkml.kernel.org/r/1772c296-1417-486f-8eef-171af2192681@moroto.mountain
Link: https://lkml.kernel.org/r/20230926192017.98183-1-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reported-and-tested-by: syzbot+c225dea486da4d5592bd@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=c225dea486da4d5592bd
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff a08c7193 Tue Sep 26 01:20:17 MDT 2023 Sidhartha Kumar <sidhartha.kumar@oracle.com> mm/filemap: remove hugetlb special casing in filemap.c

Remove special cased hugetlb handling code within the page cache by
changing the granularity of ->index to the base page size rather than the
huge page size. The motivation of this patch is to reduce complexity
within the filemap code while also increasing performance by removing
branches that are evaluated on every page cache lookup.

To support the change in index, new wrappers for hugetlb page cache
interactions are added. These wrappers perform the conversion to a linear
index which is now expected by the page cache for huge pages.

========================= PERFORMANCE ======================================

Perf was used to check the performance differences after the patch.
Overall the performance is similar to mainline with a very small larger
overhead that occurs in __filemap_add_folio() and
hugetlb_add_to_page_cache(). This is because of the larger overhead that
occurs in xa_load() and xa_store() as the xarray is now using more entries
to store hugetlb folios in the page cache.

Timing

aarch64
2MB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-1 hugepages]# time fallocate -l 700GB test.txt
real 1m49.568s
user 0m0.000s
sys 1m49.461s

6.5-rc3:
[root]# time fallocate -l 700GB test.txt
real 1m47.495s
user 0m0.000s
sys 1m47.370s
1GB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
real 1m47.024s
user 0m0.000s
sys 1m46.921s

6.5-rc3:
[root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
real 1m44.551s
user 0m0.000s
sys 1m44.438s

x86
2MB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-2 hugepages]# time fallocate -l 100GB test.txt
real 0m22.383s
user 0m0.000s
sys 0m22.255s

6.5-rc3:
[opc@sidhakum-ol9-2 hugepages]$ time sudo fallocate -l 100GB /dev/hugepages/test.txt
real 0m22.735s
user 0m0.038s
sys 0m22.567s

1GB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-2 hugepages1GB]# time fallocate -l 100GB test.txt
real 0m25.786s
user 0m0.001s
sys 0m25.589s

6.5-rc3:
[root@sidhakum-ol9-2 hugepages1G]# time fallocate -l 100GB test.txt
real 0m33.454s
user 0m0.001s
sys 0m33.193s

aarch64:
workload - fallocate a 700GB file backed by huge pages

6.5-rc3 + this patch:
2MB Page Size:
--100.00%--__arm64_sys_fallocate
ksys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
|--95.04%--__pi_clear_page
|
|--3.57%--clear_huge_page
| |
| |--2.63%--rcu_all_qs
| |
| --0.91%--__cond_resched
|
--0.67%--__cond_resched
0.17% 0.00% 0 fallocate [kernel.vmlinux] [k] hugetlb_add_to_page_cache
0.14% 0.10% 11 fallocate [kernel.vmlinux] [k] __filemap_add_folio

6.5-rc3
2MB Page Size:
--100.00%--__arm64_sys_fallocate
ksys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
|--94.91%--__pi_clear_page
|
|--4.11%--clear_huge_page
| |
| |--3.00%--rcu_all_qs
| |
| --1.10%--__cond_resched
|
--0.59%--__cond_resched
0.08% 0.01% 1 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache
0.05% 0.03% 3 fallocate [kernel.kallsyms] [k] __filemap_add_folio

x86
workload - fallocate a 100GB file backed by huge pages

6.5-rc3 + this patch:
2MB Page Size:
hugetlbfs_fallocate
|
--99.57%--clear_huge_page
|
--98.47%--clear_page_erms
|
--0.53%--asm_sysvec_apic_timer_interrupt

0.04% 0.04% 1 fallocate [kernel.kallsyms] [k] xa_load
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] __filemap_add_folio
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] xas_store

6.5-rc3
2MB Page Size:
--99.93%--__x64_sys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
--99.38%--clear_huge_page
|
|--98.40%--clear_page_erms
|
--0.59%--__cond_resched
0.03% 0.03% 1 fallocate [kernel.kallsyms] [k] __filemap_add_folio

========================= TESTING ======================================

This patch passes libhugetlbfs tests and LTP hugetlb tests

********** TEST SUMMARY
* 2M
* 32-bit 64-bit
* Total testcases: 110 113
* Skipped: 0 0
* PASS: 107 113
* FAIL: 0 0
* Killed by signal: 3 0
* Bad configuration: 0 0
* Expected FAIL: 0 0
* Unexpected PASS: 0 0
* Test not present: 0 0
* Strange test result: 0 0
**********

Done executing testcases.
LTP Version: 20220527-178-g2761a81c4

page migration was also tested using Mike Kravetz's test program.[8]

[dan.carpenter@linaro.org: fix an NULL vs IS_ERR() bug]
Link: https://lkml.kernel.org/r/1772c296-1417-486f-8eef-171af2192681@moroto.mountain
Link: https://lkml.kernel.org/r/20230926192017.98183-1-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reported-and-tested-by: syzbot+c225dea486da4d5592bd@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=c225dea486da4d5592bd
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff a08c7193 Tue Sep 26 01:20:17 MDT 2023 Sidhartha Kumar <sidhartha.kumar@oracle.com> mm/filemap: remove hugetlb special casing in filemap.c

Remove special cased hugetlb handling code within the page cache by
changing the granularity of ->index to the base page size rather than the
huge page size. The motivation of this patch is to reduce complexity
within the filemap code while also increasing performance by removing
branches that are evaluated on every page cache lookup.

To support the change in index, new wrappers for hugetlb page cache
interactions are added. These wrappers perform the conversion to a linear
index which is now expected by the page cache for huge pages.

========================= PERFORMANCE ======================================

Perf was used to check the performance differences after the patch.
Overall the performance is similar to mainline with a very small larger
overhead that occurs in __filemap_add_folio() and
hugetlb_add_to_page_cache(). This is because of the larger overhead that
occurs in xa_load() and xa_store() as the xarray is now using more entries
to store hugetlb folios in the page cache.

Timing

aarch64
2MB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-1 hugepages]# time fallocate -l 700GB test.txt
real 1m49.568s
user 0m0.000s
sys 1m49.461s

6.5-rc3:
[root]# time fallocate -l 700GB test.txt
real 1m47.495s
user 0m0.000s
sys 1m47.370s
1GB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
real 1m47.024s
user 0m0.000s
sys 1m46.921s

6.5-rc3:
[root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
real 1m44.551s
user 0m0.000s
sys 1m44.438s

x86
2MB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-2 hugepages]# time fallocate -l 100GB test.txt
real 0m22.383s
user 0m0.000s
sys 0m22.255s

6.5-rc3:
[opc@sidhakum-ol9-2 hugepages]$ time sudo fallocate -l 100GB /dev/hugepages/test.txt
real 0m22.735s
user 0m0.038s
sys 0m22.567s

1GB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-2 hugepages1GB]# time fallocate -l 100GB test.txt
real 0m25.786s
user 0m0.001s
sys 0m25.589s

6.5-rc3:
[root@sidhakum-ol9-2 hugepages1G]# time fallocate -l 100GB test.txt
real 0m33.454s
user 0m0.001s
sys 0m33.193s

aarch64:
workload - fallocate a 700GB file backed by huge pages

6.5-rc3 + this patch:
2MB Page Size:
--100.00%--__arm64_sys_fallocate
ksys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
|--95.04%--__pi_clear_page
|
|--3.57%--clear_huge_page
| |
| |--2.63%--rcu_all_qs
| |
| --0.91%--__cond_resched
|
--0.67%--__cond_resched
0.17% 0.00% 0 fallocate [kernel.vmlinux] [k] hugetlb_add_to_page_cache
0.14% 0.10% 11 fallocate [kernel.vmlinux] [k] __filemap_add_folio

6.5-rc3
2MB Page Size:
--100.00%--__arm64_sys_fallocate
ksys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
|--94.91%--__pi_clear_page
|
|--4.11%--clear_huge_page
| |
| |--3.00%--rcu_all_qs
| |
| --1.10%--__cond_resched
|
--0.59%--__cond_resched
0.08% 0.01% 1 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache
0.05% 0.03% 3 fallocate [kernel.kallsyms] [k] __filemap_add_folio

x86
workload - fallocate a 100GB file backed by huge pages

6.5-rc3 + this patch:
2MB Page Size:
hugetlbfs_fallocate
|
--99.57%--clear_huge_page
|
--98.47%--clear_page_erms
|
--0.53%--asm_sysvec_apic_timer_interrupt

0.04% 0.04% 1 fallocate [kernel.kallsyms] [k] xa_load
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] __filemap_add_folio
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] xas_store

6.5-rc3
2MB Page Size:
--99.93%--__x64_sys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
--99.38%--clear_huge_page
|
|--98.40%--clear_page_erms
|
--0.59%--__cond_resched
0.03% 0.03% 1 fallocate [kernel.kallsyms] [k] __filemap_add_folio

========================= TESTING ======================================

This patch passes libhugetlbfs tests and LTP hugetlb tests

********** TEST SUMMARY
* 2M
* 32-bit 64-bit
* Total testcases: 110 113
* Skipped: 0 0
* PASS: 107 113
* FAIL: 0 0
* Killed by signal: 3 0
* Bad configuration: 0 0
* Expected FAIL: 0 0
* Unexpected PASS: 0 0
* Test not present: 0 0
* Strange test result: 0 0
**********

Done executing testcases.
LTP Version: 20220527-178-g2761a81c4

page migration was also tested using Mike Kravetz's test program.[8]

[dan.carpenter@linaro.org: fix an NULL vs IS_ERR() bug]
Link: https://lkml.kernel.org/r/1772c296-1417-486f-8eef-171af2192681@moroto.mountain
Link: https://lkml.kernel.org/r/20230926192017.98183-1-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reported-and-tested-by: syzbot+c225dea486da4d5592bd@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=c225dea486da4d5592bd
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff a08c7193 Tue Sep 26 01:20:17 MDT 2023 Sidhartha Kumar <sidhartha.kumar@oracle.com> mm/filemap: remove hugetlb special casing in filemap.c

Remove special cased hugetlb handling code within the page cache by
changing the granularity of ->index to the base page size rather than the
huge page size. The motivation of this patch is to reduce complexity
within the filemap code while also increasing performance by removing
branches that are evaluated on every page cache lookup.

To support the change in index, new wrappers for hugetlb page cache
interactions are added. These wrappers perform the conversion to a linear
index which is now expected by the page cache for huge pages.

========================= PERFORMANCE ======================================

Perf was used to check the performance differences after the patch.
Overall the performance is similar to mainline with a very small larger
overhead that occurs in __filemap_add_folio() and
hugetlb_add_to_page_cache(). This is because of the larger overhead that
occurs in xa_load() and xa_store() as the xarray is now using more entries
to store hugetlb folios in the page cache.

Timing

aarch64
2MB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-1 hugepages]# time fallocate -l 700GB test.txt
real 1m49.568s
user 0m0.000s
sys 1m49.461s

6.5-rc3:
[root]# time fallocate -l 700GB test.txt
real 1m47.495s
user 0m0.000s
sys 1m47.370s
1GB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
real 1m47.024s
user 0m0.000s
sys 1m46.921s

6.5-rc3:
[root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
real 1m44.551s
user 0m0.000s
sys 1m44.438s

x86
2MB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-2 hugepages]# time fallocate -l 100GB test.txt
real 0m22.383s
user 0m0.000s
sys 0m22.255s

6.5-rc3:
[opc@sidhakum-ol9-2 hugepages]$ time sudo fallocate -l 100GB /dev/hugepages/test.txt
real 0m22.735s
user 0m0.038s
sys 0m22.567s

1GB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-2 hugepages1GB]# time fallocate -l 100GB test.txt
real 0m25.786s
user 0m0.001s
sys 0m25.589s

6.5-rc3:
[root@sidhakum-ol9-2 hugepages1G]# time fallocate -l 100GB test.txt
real 0m33.454s
user 0m0.001s
sys 0m33.193s

aarch64:
workload - fallocate a 700GB file backed by huge pages

6.5-rc3 + this patch:
2MB Page Size:
--100.00%--__arm64_sys_fallocate
ksys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
|--95.04%--__pi_clear_page
|
|--3.57%--clear_huge_page
| |
| |--2.63%--rcu_all_qs
| |
| --0.91%--__cond_resched
|
--0.67%--__cond_resched
0.17% 0.00% 0 fallocate [kernel.vmlinux] [k] hugetlb_add_to_page_cache
0.14% 0.10% 11 fallocate [kernel.vmlinux] [k] __filemap_add_folio

6.5-rc3
2MB Page Size:
--100.00%--__arm64_sys_fallocate
ksys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
|--94.91%--__pi_clear_page
|
|--4.11%--clear_huge_page
| |
| |--3.00%--rcu_all_qs
| |
| --1.10%--__cond_resched
|
--0.59%--__cond_resched
0.08% 0.01% 1 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache
0.05% 0.03% 3 fallocate [kernel.kallsyms] [k] __filemap_add_folio

x86
workload - fallocate a 100GB file backed by huge pages

6.5-rc3 + this patch:
2MB Page Size:
hugetlbfs_fallocate
|
--99.57%--clear_huge_page
|
--98.47%--clear_page_erms
|
--0.53%--asm_sysvec_apic_timer_interrupt

0.04% 0.04% 1 fallocate [kernel.kallsyms] [k] xa_load
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] __filemap_add_folio
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] xas_store

6.5-rc3
2MB Page Size:
--99.93%--__x64_sys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
--99.38%--clear_huge_page
|
|--98.40%--clear_page_erms
|
--0.59%--__cond_resched
0.03% 0.03% 1 fallocate [kernel.kallsyms] [k] __filemap_add_folio

========================= TESTING ======================================

This patch passes libhugetlbfs tests and LTP hugetlb tests

********** TEST SUMMARY
* 2M
* 32-bit 64-bit
* Total testcases: 110 113
* Skipped: 0 0
* PASS: 107 113
* FAIL: 0 0
* Killed by signal: 3 0
* Bad configuration: 0 0
* Expected FAIL: 0 0
* Unexpected PASS: 0 0
* Test not present: 0 0
* Strange test result: 0 0
**********

Done executing testcases.
LTP Version: 20220527-178-g2761a81c4

page migration was also tested using Mike Kravetz's test program.[8]

[dan.carpenter@linaro.org: fix an NULL vs IS_ERR() bug]
Link: https://lkml.kernel.org/r/1772c296-1417-486f-8eef-171af2192681@moroto.mountain
Link: https://lkml.kernel.org/r/20230926192017.98183-1-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reported-and-tested-by: syzbot+c225dea486da4d5592bd@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=c225dea486da4d5592bd
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff a08c7193 Tue Sep 26 01:20:17 MDT 2023 Sidhartha Kumar <sidhartha.kumar@oracle.com> mm/filemap: remove hugetlb special casing in filemap.c

Remove special cased hugetlb handling code within the page cache by
changing the granularity of ->index to the base page size rather than the
huge page size. The motivation of this patch is to reduce complexity
within the filemap code while also increasing performance by removing
branches that are evaluated on every page cache lookup.

To support the change in index, new wrappers for hugetlb page cache
interactions are added. These wrappers perform the conversion to a linear
index which is now expected by the page cache for huge pages.

========================= PERFORMANCE ======================================

Perf was used to check the performance differences after the patch.
Overall the performance is similar to mainline with a very small larger
overhead that occurs in __filemap_add_folio() and
hugetlb_add_to_page_cache(). This is because of the larger overhead that
occurs in xa_load() and xa_store() as the xarray is now using more entries
to store hugetlb folios in the page cache.

Timing

aarch64
2MB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-1 hugepages]# time fallocate -l 700GB test.txt
real 1m49.568s
user 0m0.000s
sys 1m49.461s

6.5-rc3:
[root]# time fallocate -l 700GB test.txt
real 1m47.495s
user 0m0.000s
sys 1m47.370s
1GB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
real 1m47.024s
user 0m0.000s
sys 1m46.921s

6.5-rc3:
[root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
real 1m44.551s
user 0m0.000s
sys 1m44.438s

x86
2MB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-2 hugepages]# time fallocate -l 100GB test.txt
real 0m22.383s
user 0m0.000s
sys 0m22.255s

6.5-rc3:
[opc@sidhakum-ol9-2 hugepages]$ time sudo fallocate -l 100GB /dev/hugepages/test.txt
real 0m22.735s
user 0m0.038s
sys 0m22.567s

1GB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-2 hugepages1GB]# time fallocate -l 100GB test.txt
real 0m25.786s
user 0m0.001s
sys 0m25.589s

6.5-rc3:
[root@sidhakum-ol9-2 hugepages1G]# time fallocate -l 100GB test.txt
real 0m33.454s
user 0m0.001s
sys 0m33.193s

aarch64:
workload - fallocate a 700GB file backed by huge pages

6.5-rc3 + this patch:
2MB Page Size:
--100.00%--__arm64_sys_fallocate
ksys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
|--95.04%--__pi_clear_page
|
|--3.57%--clear_huge_page
| |
| |--2.63%--rcu_all_qs
| |
| --0.91%--__cond_resched
|
--0.67%--__cond_resched
0.17% 0.00% 0 fallocate [kernel.vmlinux] [k] hugetlb_add_to_page_cache
0.14% 0.10% 11 fallocate [kernel.vmlinux] [k] __filemap_add_folio

6.5-rc3
2MB Page Size:
--100.00%--__arm64_sys_fallocate
ksys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
|--94.91%--__pi_clear_page
|
|--4.11%--clear_huge_page
| |
| |--3.00%--rcu_all_qs
| |
| --1.10%--__cond_resched
|
--0.59%--__cond_resched
0.08% 0.01% 1 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache
0.05% 0.03% 3 fallocate [kernel.kallsyms] [k] __filemap_add_folio

x86
workload - fallocate a 100GB file backed by huge pages

6.5-rc3 + this patch:
2MB Page Size:
hugetlbfs_fallocate
|
--99.57%--clear_huge_page
|
--98.47%--clear_page_erms
|
--0.53%--asm_sysvec_apic_timer_interrupt

0.04% 0.04% 1 fallocate [kernel.kallsyms] [k] xa_load
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] __filemap_add_folio
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] xas_store

6.5-rc3
2MB Page Size:
--99.93%--__x64_sys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
--99.38%--clear_huge_page
|
|--98.40%--clear_page_erms
|
--0.59%--__cond_resched
0.03% 0.03% 1 fallocate [kernel.kallsyms] [k] __filemap_add_folio

========================= TESTING ======================================

This patch passes libhugetlbfs tests and LTP hugetlb tests

********** TEST SUMMARY
* 2M
* 32-bit 64-bit
* Total testcases: 110 113
* Skipped: 0 0
* PASS: 107 113
* FAIL: 0 0
* Killed by signal: 3 0
* Bad configuration: 0 0
* Expected FAIL: 0 0
* Unexpected PASS: 0 0
* Test not present: 0 0
* Strange test result: 0 0
**********

Done executing testcases.
LTP Version: 20220527-178-g2761a81c4

page migration was also tested using Mike Kravetz's test program.[8]

[dan.carpenter@linaro.org: fix an NULL vs IS_ERR() bug]
Link: https://lkml.kernel.org/r/1772c296-1417-486f-8eef-171af2192681@moroto.mountain
Link: https://lkml.kernel.org/r/20230926192017.98183-1-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reported-and-tested-by: syzbot+c225dea486da4d5592bd@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=c225dea486da4d5592bd
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff a08c7193 Tue Sep 26 01:20:17 MDT 2023 Sidhartha Kumar <sidhartha.kumar@oracle.com> mm/filemap: remove hugetlb special casing in filemap.c

Remove special cased hugetlb handling code within the page cache by
changing the granularity of ->index to the base page size rather than the
huge page size. The motivation of this patch is to reduce complexity
within the filemap code while also increasing performance by removing
branches that are evaluated on every page cache lookup.

To support the change in index, new wrappers for hugetlb page cache
interactions are added. These wrappers perform the conversion to a linear
index which is now expected by the page cache for huge pages.

========================= PERFORMANCE ======================================

Perf was used to check the performance differences after the patch.
Overall the performance is similar to mainline with a very small larger
overhead that occurs in __filemap_add_folio() and
hugetlb_add_to_page_cache(). This is because of the larger overhead that
occurs in xa_load() and xa_store() as the xarray is now using more entries
to store hugetlb folios in the page cache.

Timing

aarch64
2MB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-1 hugepages]# time fallocate -l 700GB test.txt
real 1m49.568s
user 0m0.000s
sys 1m49.461s

6.5-rc3:
[root]# time fallocate -l 700GB test.txt
real 1m47.495s
user 0m0.000s
sys 1m47.370s
1GB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
real 1m47.024s
user 0m0.000s
sys 1m46.921s

6.5-rc3:
[root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
real 1m44.551s
user 0m0.000s
sys 1m44.438s

x86
2MB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-2 hugepages]# time fallocate -l 100GB test.txt
real 0m22.383s
user 0m0.000s
sys 0m22.255s

6.5-rc3:
[opc@sidhakum-ol9-2 hugepages]$ time sudo fallocate -l 100GB /dev/hugepages/test.txt
real 0m22.735s
user 0m0.038s
sys 0m22.567s

1GB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-2 hugepages1GB]# time fallocate -l 100GB test.txt
real 0m25.786s
user 0m0.001s
sys 0m25.589s

6.5-rc3:
[root@sidhakum-ol9-2 hugepages1G]# time fallocate -l 100GB test.txt
real 0m33.454s
user 0m0.001s
sys 0m33.193s

aarch64:
workload - fallocate a 700GB file backed by huge pages

6.5-rc3 + this patch:
2MB Page Size:
--100.00%--__arm64_sys_fallocate
ksys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
|--95.04%--__pi_clear_page
|
|--3.57%--clear_huge_page
| |
| |--2.63%--rcu_all_qs
| |
| --0.91%--__cond_resched
|
--0.67%--__cond_resched
0.17% 0.00% 0 fallocate [kernel.vmlinux] [k] hugetlb_add_to_page_cache
0.14% 0.10% 11 fallocate [kernel.vmlinux] [k] __filemap_add_folio

6.5-rc3
2MB Page Size:
--100.00%--__arm64_sys_fallocate
ksys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
|--94.91%--__pi_clear_page
|
|--4.11%--clear_huge_page
| |
| |--3.00%--rcu_all_qs
| |
| --1.10%--__cond_resched
|
--0.59%--__cond_resched
0.08% 0.01% 1 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache
0.05% 0.03% 3 fallocate [kernel.kallsyms] [k] __filemap_add_folio

x86
workload - fallocate a 100GB file backed by huge pages

6.5-rc3 + this patch:
2MB Page Size:
hugetlbfs_fallocate
|
--99.57%--clear_huge_page
|
--98.47%--clear_page_erms
|
--0.53%--asm_sysvec_apic_timer_interrupt

0.04% 0.04% 1 fallocate [kernel.kallsyms] [k] xa_load
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] __filemap_add_folio
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] xas_store

6.5-rc3
2MB Page Size:
--99.93%--__x64_sys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
--99.38%--clear_huge_page
|
|--98.40%--clear_page_erms
|
--0.59%--__cond_resched
0.03% 0.03% 1 fallocate [kernel.kallsyms] [k] __filemap_add_folio

========================= TESTING ======================================

This patch passes libhugetlbfs tests and LTP hugetlb tests

********** TEST SUMMARY
* 2M
* 32-bit 64-bit
* Total testcases: 110 113
* Skipped: 0 0
* PASS: 107 113
* FAIL: 0 0
* Killed by signal: 3 0
* Bad configuration: 0 0
* Expected FAIL: 0 0
* Unexpected PASS: 0 0
* Test not present: 0 0
* Strange test result: 0 0
**********

Done executing testcases.
LTP Version: 20220527-178-g2761a81c4

page migration was also tested using Mike Kravetz's test program.[8]

[dan.carpenter@linaro.org: fix an NULL vs IS_ERR() bug]
Link: https://lkml.kernel.org/r/1772c296-1417-486f-8eef-171af2192681@moroto.mountain
Link: https://lkml.kernel.org/r/20230926192017.98183-1-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reported-and-tested-by: syzbot+c225dea486da4d5592bd@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=c225dea486da4d5592bd
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff a08c7193 Tue Sep 26 01:20:17 MDT 2023 Sidhartha Kumar <sidhartha.kumar@oracle.com> mm/filemap: remove hugetlb special casing in filemap.c

Remove special cased hugetlb handling code within the page cache by
changing the granularity of ->index to the base page size rather than the
huge page size. The motivation of this patch is to reduce complexity
within the filemap code while also increasing performance by removing
branches that are evaluated on every page cache lookup.

To support the change in index, new wrappers for hugetlb page cache
interactions are added. These wrappers perform the conversion to a linear
index which is now expected by the page cache for huge pages.

========================= PERFORMANCE ======================================

Perf was used to check the performance differences after the patch.
Overall the performance is similar to mainline with a very small larger
overhead that occurs in __filemap_add_folio() and
hugetlb_add_to_page_cache(). This is because of the larger overhead that
occurs in xa_load() and xa_store() as the xarray is now using more entries
to store hugetlb folios in the page cache.

Timing

aarch64
2MB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-1 hugepages]# time fallocate -l 700GB test.txt
real 1m49.568s
user 0m0.000s
sys 1m49.461s

6.5-rc3:
[root]# time fallocate -l 700GB test.txt
real 1m47.495s
user 0m0.000s
sys 1m47.370s
1GB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
real 1m47.024s
user 0m0.000s
sys 1m46.921s

6.5-rc3:
[root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
real 1m44.551s
user 0m0.000s
sys 1m44.438s

x86
2MB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-2 hugepages]# time fallocate -l 100GB test.txt
real 0m22.383s
user 0m0.000s
sys 0m22.255s

6.5-rc3:
[opc@sidhakum-ol9-2 hugepages]$ time sudo fallocate -l 100GB /dev/hugepages/test.txt
real 0m22.735s
user 0m0.038s
sys 0m22.567s

1GB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-2 hugepages1GB]# time fallocate -l 100GB test.txt
real 0m25.786s
user 0m0.001s
sys 0m25.589s

6.5-rc3:
[root@sidhakum-ol9-2 hugepages1G]# time fallocate -l 100GB test.txt
real 0m33.454s
user 0m0.001s
sys 0m33.193s

aarch64:
workload - fallocate a 700GB file backed by huge pages

6.5-rc3 + this patch:
2MB Page Size:
--100.00%--__arm64_sys_fallocate
ksys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
|--95.04%--__pi_clear_page
|
|--3.57%--clear_huge_page
| |
| |--2.63%--rcu_all_qs
| |
| --0.91%--__cond_resched
|
--0.67%--__cond_resched
0.17% 0.00% 0 fallocate [kernel.vmlinux] [k] hugetlb_add_to_page_cache
0.14% 0.10% 11 fallocate [kernel.vmlinux] [k] __filemap_add_folio

6.5-rc3
2MB Page Size:
--100.00%--__arm64_sys_fallocate
ksys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
|--94.91%--__pi_clear_page
|
|--4.11%--clear_huge_page
| |
| |--3.00%--rcu_all_qs
| |
| --1.10%--__cond_resched
|
--0.59%--__cond_resched
0.08% 0.01% 1 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache
0.05% 0.03% 3 fallocate [kernel.kallsyms] [k] __filemap_add_folio

x86
workload - fallocate a 100GB file backed by huge pages

6.5-rc3 + this patch:
2MB Page Size:
hugetlbfs_fallocate
|
--99.57%--clear_huge_page
|
--98.47%--clear_page_erms
|
--0.53%--asm_sysvec_apic_timer_interrupt

0.04% 0.04% 1 fallocate [kernel.kallsyms] [k] xa_load
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] __filemap_add_folio
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] xas_store

6.5-rc3
2MB Page Size:
--99.93%--__x64_sys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
--99.38%--clear_huge_page
|
|--98.40%--clear_page_erms
|
--0.59%--__cond_resched
0.03% 0.03% 1 fallocate [kernel.kallsyms] [k] __filemap_add_folio

========================= TESTING ======================================

This patch passes libhugetlbfs tests and LTP hugetlb tests

********** TEST SUMMARY
* 2M
* 32-bit 64-bit
* Total testcases: 110 113
* Skipped: 0 0
* PASS: 107 113
* FAIL: 0 0
* Killed by signal: 3 0
* Bad configuration: 0 0
* Expected FAIL: 0 0
* Unexpected PASS: 0 0
* Test not present: 0 0
* Strange test result: 0 0
**********

Done executing testcases.
LTP Version: 20220527-178-g2761a81c4

page migration was also tested using Mike Kravetz's test program.[8]

[dan.carpenter@linaro.org: fix an NULL vs IS_ERR() bug]
Link: https://lkml.kernel.org/r/1772c296-1417-486f-8eef-171af2192681@moroto.mountain
Link: https://lkml.kernel.org/r/20230926192017.98183-1-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reported-and-tested-by: syzbot+c225dea486da4d5592bd@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=c225dea486da4d5592bd
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff a08c7193 Tue Sep 26 01:20:17 MDT 2023 Sidhartha Kumar <sidhartha.kumar@oracle.com> mm/filemap: remove hugetlb special casing in filemap.c

Remove special cased hugetlb handling code within the page cache by
changing the granularity of ->index to the base page size rather than the
huge page size. The motivation of this patch is to reduce complexity
within the filemap code while also increasing performance by removing
branches that are evaluated on every page cache lookup.

To support the change in index, new wrappers for hugetlb page cache
interactions are added. These wrappers perform the conversion to a linear
index which is now expected by the page cache for huge pages.

========================= PERFORMANCE ======================================

Perf was used to check the performance differences after the patch.
Overall the performance is similar to mainline with a very small larger
overhead that occurs in __filemap_add_folio() and
hugetlb_add_to_page_cache(). This is because of the larger overhead that
occurs in xa_load() and xa_store() as the xarray is now using more entries
to store hugetlb folios in the page cache.

Timing

aarch64
2MB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-1 hugepages]# time fallocate -l 700GB test.txt
real 1m49.568s
user 0m0.000s
sys 1m49.461s

6.5-rc3:
[root]# time fallocate -l 700GB test.txt
real 1m47.495s
user 0m0.000s
sys 1m47.370s
1GB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
real 1m47.024s
user 0m0.000s
sys 1m46.921s

6.5-rc3:
[root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
real 1m44.551s
user 0m0.000s
sys 1m44.438s

x86
2MB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-2 hugepages]# time fallocate -l 100GB test.txt
real 0m22.383s
user 0m0.000s
sys 0m22.255s

6.5-rc3:
[opc@sidhakum-ol9-2 hugepages]$ time sudo fallocate -l 100GB /dev/hugepages/test.txt
real 0m22.735s
user 0m0.038s
sys 0m22.567s

1GB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-2 hugepages1GB]# time fallocate -l 100GB test.txt
real 0m25.786s
user 0m0.001s
sys 0m25.589s

6.5-rc3:
[root@sidhakum-ol9-2 hugepages1G]# time fallocate -l 100GB test.txt
real 0m33.454s
user 0m0.001s
sys 0m33.193s

aarch64:
workload - fallocate a 700GB file backed by huge pages

6.5-rc3 + this patch:
2MB Page Size:
--100.00%--__arm64_sys_fallocate
ksys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
|--95.04%--__pi_clear_page
|
|--3.57%--clear_huge_page
| |
| |--2.63%--rcu_all_qs
| |
| --0.91%--__cond_resched
|
--0.67%--__cond_resched
0.17% 0.00% 0 fallocate [kernel.vmlinux] [k] hugetlb_add_to_page_cache
0.14% 0.10% 11 fallocate [kernel.vmlinux] [k] __filemap_add_folio

6.5-rc3
2MB Page Size:
--100.00%--__arm64_sys_fallocate
ksys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
|--94.91%--__pi_clear_page
|
|--4.11%--clear_huge_page
| |
| |--3.00%--rcu_all_qs
| |
| --1.10%--__cond_resched
|
--0.59%--__cond_resched
0.08% 0.01% 1 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache
0.05% 0.03% 3 fallocate [kernel.kallsyms] [k] __filemap_add_folio

x86
workload - fallocate a 100GB file backed by huge pages

6.5-rc3 + this patch:
2MB Page Size:
hugetlbfs_fallocate
|
--99.57%--clear_huge_page
|
--98.47%--clear_page_erms
|
--0.53%--asm_sysvec_apic_timer_interrupt

0.04% 0.04% 1 fallocate [kernel.kallsyms] [k] xa_load
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] __filemap_add_folio
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] xas_store

6.5-rc3
2MB Page Size:
--99.93%--__x64_sys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
--99.38%--clear_huge_page
|
|--98.40%--clear_page_erms
|
--0.59%--__cond_resched
0.03% 0.03% 1 fallocate [kernel.kallsyms] [k] __filemap_add_folio

========================= TESTING ======================================

This patch passes libhugetlbfs tests and LTP hugetlb tests

********** TEST SUMMARY
* 2M
* 32-bit 64-bit
* Total testcases: 110 113
* Skipped: 0 0
* PASS: 107 113
* FAIL: 0 0
* Killed by signal: 3 0
* Bad configuration: 0 0
* Expected FAIL: 0 0
* Unexpected PASS: 0 0
* Test not present: 0 0
* Strange test result: 0 0
**********

Done executing testcases.
LTP Version: 20220527-178-g2761a81c4

page migration was also tested using Mike Kravetz's test program.[8]

[dan.carpenter@linaro.org: fix an NULL vs IS_ERR() bug]
Link: https://lkml.kernel.org/r/1772c296-1417-486f-8eef-171af2192681@moroto.mountain
Link: https://lkml.kernel.org/r/20230926192017.98183-1-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reported-and-tested-by: syzbot+c225dea486da4d5592bd@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=c225dea486da4d5592bd
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff a08c7193 Tue Sep 26 01:20:17 MDT 2023 Sidhartha Kumar <sidhartha.kumar@oracle.com> mm/filemap: remove hugetlb special casing in filemap.c

Remove special cased hugetlb handling code within the page cache by
changing the granularity of ->index to the base page size rather than the
huge page size. The motivation of this patch is to reduce complexity
within the filemap code while also increasing performance by removing
branches that are evaluated on every page cache lookup.

To support the change in index, new wrappers for hugetlb page cache
interactions are added. These wrappers perform the conversion to a linear
index which is now expected by the page cache for huge pages.

========================= PERFORMANCE ======================================

Perf was used to check the performance differences after the patch.
Overall the performance is similar to mainline with a very small larger
overhead that occurs in __filemap_add_folio() and
hugetlb_add_to_page_cache(). This is because of the larger overhead that
occurs in xa_load() and xa_store() as the xarray is now using more entries
to store hugetlb folios in the page cache.

Timing

aarch64
2MB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-1 hugepages]# time fallocate -l 700GB test.txt
real 1m49.568s
user 0m0.000s
sys 1m49.461s

6.5-rc3:
[root]# time fallocate -l 700GB test.txt
real 1m47.495s
user 0m0.000s
sys 1m47.370s
1GB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
real 1m47.024s
user 0m0.000s
sys 1m46.921s

6.5-rc3:
[root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
real 1m44.551s
user 0m0.000s
sys 1m44.438s

x86
2MB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-2 hugepages]# time fallocate -l 100GB test.txt
real 0m22.383s
user 0m0.000s
sys 0m22.255s

6.5-rc3:
[opc@sidhakum-ol9-2 hugepages]$ time sudo fallocate -l 100GB /dev/hugepages/test.txt
real 0m22.735s
user 0m0.038s
sys 0m22.567s

1GB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-2 hugepages1GB]# time fallocate -l 100GB test.txt
real 0m25.786s
user 0m0.001s
sys 0m25.589s

6.5-rc3:
[root@sidhakum-ol9-2 hugepages1G]# time fallocate -l 100GB test.txt
real 0m33.454s
user 0m0.001s
sys 0m33.193s

aarch64:
workload - fallocate a 700GB file backed by huge pages

6.5-rc3 + this patch:
2MB Page Size:
--100.00%--__arm64_sys_fallocate
ksys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
|--95.04%--__pi_clear_page
|
|--3.57%--clear_huge_page
| |
| |--2.63%--rcu_all_qs
| |
| --0.91%--__cond_resched
|
--0.67%--__cond_resched
0.17% 0.00% 0 fallocate [kernel.vmlinux] [k] hugetlb_add_to_page_cache
0.14% 0.10% 11 fallocate [kernel.vmlinux] [k] __filemap_add_folio

6.5-rc3
2MB Page Size:
--100.00%--__arm64_sys_fallocate
ksys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
|--94.91%--__pi_clear_page
|
|--4.11%--clear_huge_page
| |
| |--3.00%--rcu_all_qs
| |
| --1.10%--__cond_resched
|
--0.59%--__cond_resched
0.08% 0.01% 1 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache
0.05% 0.03% 3 fallocate [kernel.kallsyms] [k] __filemap_add_folio

x86
workload - fallocate a 100GB file backed by huge pages

6.5-rc3 + this patch:
2MB Page Size:
hugetlbfs_fallocate
|
--99.57%--clear_huge_page
|
--98.47%--clear_page_erms
|
--0.53%--asm_sysvec_apic_timer_interrupt

0.04% 0.04% 1 fallocate [kernel.kallsyms] [k] xa_load
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] __filemap_add_folio
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] xas_store

6.5-rc3
2MB Page Size:
--99.93%--__x64_sys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
--99.38%--clear_huge_page
|
|--98.40%--clear_page_erms
|
--0.59%--__cond_resched
0.03% 0.03% 1 fallocate [kernel.kallsyms] [k] __filemap_add_folio

========================= TESTING ======================================

This patch passes libhugetlbfs tests and LTP hugetlb tests

********** TEST SUMMARY
* 2M
* 32-bit 64-bit
* Total testcases: 110 113
* Skipped: 0 0
* PASS: 107 113
* FAIL: 0 0
* Killed by signal: 3 0
* Bad configuration: 0 0
* Expected FAIL: 0 0
* Unexpected PASS: 0 0
* Test not present: 0 0
* Strange test result: 0 0
**********

Done executing testcases.
LTP Version: 20220527-178-g2761a81c4

page migration was also tested using Mike Kravetz's test program.[8]

[dan.carpenter@linaro.org: fix an NULL vs IS_ERR() bug]
Link: https://lkml.kernel.org/r/1772c296-1417-486f-8eef-171af2192681@moroto.mountain
Link: https://lkml.kernel.org/r/20230926192017.98183-1-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reported-and-tested-by: syzbot+c225dea486da4d5592bd@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=c225dea486da4d5592bd
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff a08c7193 Tue Sep 26 01:20:17 MDT 2023 Sidhartha Kumar <sidhartha.kumar@oracle.com> mm/filemap: remove hugetlb special casing in filemap.c

Remove special cased hugetlb handling code within the page cache by
changing the granularity of ->index to the base page size rather than the
huge page size. The motivation of this patch is to reduce complexity
within the filemap code while also increasing performance by removing
branches that are evaluated on every page cache lookup.

To support the change in index, new wrappers for hugetlb page cache
interactions are added. These wrappers perform the conversion to a linear
index which is now expected by the page cache for huge pages.

========================= PERFORMANCE ======================================

Perf was used to check the performance differences after the patch.
Overall the performance is similar to mainline with a very small larger
overhead that occurs in __filemap_add_folio() and
hugetlb_add_to_page_cache(). This is because of the larger overhead that
occurs in xa_load() and xa_store() as the xarray is now using more entries
to store hugetlb folios in the page cache.

Timing

aarch64
2MB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-1 hugepages]# time fallocate -l 700GB test.txt
real 1m49.568s
user 0m0.000s
sys 1m49.461s

6.5-rc3:
[root]# time fallocate -l 700GB test.txt
real 1m47.495s
user 0m0.000s
sys 1m47.370s
1GB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
real 1m47.024s
user 0m0.000s
sys 1m46.921s

6.5-rc3:
[root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
real 1m44.551s
user 0m0.000s
sys 1m44.438s

x86
2MB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-2 hugepages]# time fallocate -l 100GB test.txt
real 0m22.383s
user 0m0.000s
sys 0m22.255s

6.5-rc3:
[opc@sidhakum-ol9-2 hugepages]$ time sudo fallocate -l 100GB /dev/hugepages/test.txt
real 0m22.735s
user 0m0.038s
sys 0m22.567s

1GB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-2 hugepages1GB]# time fallocate -l 100GB test.txt
real 0m25.786s
user 0m0.001s
sys 0m25.589s

6.5-rc3:
[root@sidhakum-ol9-2 hugepages1G]# time fallocate -l 100GB test.txt
real 0m33.454s
user 0m0.001s
sys 0m33.193s

aarch64:
workload - fallocate a 700GB file backed by huge pages

6.5-rc3 + this patch:
2MB Page Size:
--100.00%--__arm64_sys_fallocate
ksys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
|--95.04%--__pi_clear_page
|
|--3.57%--clear_huge_page
| |
| |--2.63%--rcu_all_qs
| |
| --0.91%--__cond_resched
|
--0.67%--__cond_resched
0.17% 0.00% 0 fallocate [kernel.vmlinux] [k] hugetlb_add_to_page_cache
0.14% 0.10% 11 fallocate [kernel.vmlinux] [k] __filemap_add_folio

6.5-rc3
2MB Page Size:
--100.00%--__arm64_sys_fallocate
ksys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
|--94.91%--__pi_clear_page
|
|--4.11%--clear_huge_page
| |
| |--3.00%--rcu_all_qs
| |
| --1.10%--__cond_resched
|
--0.59%--__cond_resched
0.08% 0.01% 1 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache
0.05% 0.03% 3 fallocate [kernel.kallsyms] [k] __filemap_add_folio

x86
workload - fallocate a 100GB file backed by huge pages

6.5-rc3 + this patch:
2MB Page Size:
hugetlbfs_fallocate
|
--99.57%--clear_huge_page
|
--98.47%--clear_page_erms
|
--0.53%--asm_sysvec_apic_timer_interrupt

0.04% 0.04% 1 fallocate [kernel.kallsyms] [k] xa_load
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] __filemap_add_folio
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] xas_store

6.5-rc3
2MB Page Size:
--99.93%--__x64_sys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
--99.38%--clear_huge_page
|
|--98.40%--clear_page_erms
|
--0.59%--__cond_resched
0.03% 0.03% 1 fallocate [kernel.kallsyms] [k] __filemap_add_folio

========================= TESTING ======================================

This patch passes libhugetlbfs tests and LTP hugetlb tests

********** TEST SUMMARY
* 2M
* 32-bit 64-bit
* Total testcases: 110 113
* Skipped: 0 0
* PASS: 107 113
* FAIL: 0 0
* Killed by signal: 3 0
* Bad configuration: 0 0
* Expected FAIL: 0 0
* Unexpected PASS: 0 0
* Test not present: 0 0
* Strange test result: 0 0
**********

Done executing testcases.
LTP Version: 20220527-178-g2761a81c4

page migration was also tested using Mike Kravetz's test program.[8]

[dan.carpenter@linaro.org: fix an NULL vs IS_ERR() bug]
Link: https://lkml.kernel.org/r/1772c296-1417-486f-8eef-171af2192681@moroto.mountain
Link: https://lkml.kernel.org/r/20230926192017.98183-1-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reported-and-tested-by: syzbot+c225dea486da4d5592bd@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=c225dea486da4d5592bd
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff a08c7193 Tue Sep 26 01:20:17 MDT 2023 Sidhartha Kumar <sidhartha.kumar@oracle.com> mm/filemap: remove hugetlb special casing in filemap.c

Remove special cased hugetlb handling code within the page cache by
changing the granularity of ->index to the base page size rather than the
huge page size. The motivation of this patch is to reduce complexity
within the filemap code while also increasing performance by removing
branches that are evaluated on every page cache lookup.

To support the change in index, new wrappers for hugetlb page cache
interactions are added. These wrappers perform the conversion to a linear
index which is now expected by the page cache for huge pages.

========================= PERFORMANCE ======================================

Perf was used to check the performance differences after the patch.
Overall the performance is similar to mainline with a very small larger
overhead that occurs in __filemap_add_folio() and
hugetlb_add_to_page_cache(). This is because of the larger overhead that
occurs in xa_load() and xa_store() as the xarray is now using more entries
to store hugetlb folios in the page cache.

Timing

aarch64
2MB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-1 hugepages]# time fallocate -l 700GB test.txt
real 1m49.568s
user 0m0.000s
sys 1m49.461s

6.5-rc3:
[root]# time fallocate -l 700GB test.txt
real 1m47.495s
user 0m0.000s
sys 1m47.370s
1GB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
real 1m47.024s
user 0m0.000s
sys 1m46.921s

6.5-rc3:
[root@sidhakum-ol9-1 hugepages1G]# time fallocate -l 700GB test.txt
real 1m44.551s
user 0m0.000s
sys 1m44.438s

x86
2MB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-2 hugepages]# time fallocate -l 100GB test.txt
real 0m22.383s
user 0m0.000s
sys 0m22.255s

6.5-rc3:
[opc@sidhakum-ol9-2 hugepages]$ time sudo fallocate -l 100GB /dev/hugepages/test.txt
real 0m22.735s
user 0m0.038s
sys 0m22.567s

1GB Page Size
6.5-rc3 + this patch:
[root@sidhakum-ol9-2 hugepages1GB]# time fallocate -l 100GB test.txt
real 0m25.786s
user 0m0.001s
sys 0m25.589s

6.5-rc3:
[root@sidhakum-ol9-2 hugepages1G]# time fallocate -l 100GB test.txt
real 0m33.454s
user 0m0.001s
sys 0m33.193s

aarch64:
workload - fallocate a 700GB file backed by huge pages

6.5-rc3 + this patch:
2MB Page Size:
--100.00%--__arm64_sys_fallocate
ksys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
|--95.04%--__pi_clear_page
|
|--3.57%--clear_huge_page
| |
| |--2.63%--rcu_all_qs
| |
| --0.91%--__cond_resched
|
--0.67%--__cond_resched
0.17% 0.00% 0 fallocate [kernel.vmlinux] [k] hugetlb_add_to_page_cache
0.14% 0.10% 11 fallocate [kernel.vmlinux] [k] __filemap_add_folio

6.5-rc3
2MB Page Size:
--100.00%--__arm64_sys_fallocate
ksys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
|--94.91%--__pi_clear_page
|
|--4.11%--clear_huge_page
| |
| |--3.00%--rcu_all_qs
| |
| --1.10%--__cond_resched
|
--0.59%--__cond_resched
0.08% 0.01% 1 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache
0.05% 0.03% 3 fallocate [kernel.kallsyms] [k] __filemap_add_folio

x86
workload - fallocate a 100GB file backed by huge pages

6.5-rc3 + this patch:
2MB Page Size:
hugetlbfs_fallocate
|
--99.57%--clear_huge_page
|
--98.47%--clear_page_erms
|
--0.53%--asm_sysvec_apic_timer_interrupt

0.04% 0.04% 1 fallocate [kernel.kallsyms] [k] xa_load
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] hugetlb_add_to_page_cache
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] __filemap_add_folio
0.04% 0.00% 0 fallocate [kernel.kallsyms] [k] xas_store

6.5-rc3
2MB Page Size:
--99.93%--__x64_sys_fallocate
vfs_fallocate
hugetlbfs_fallocate
|
--99.38%--clear_huge_page
|
|--98.40%--clear_page_erms
|
--0.59%--__cond_resched
0.03% 0.03% 1 fallocate [kernel.kallsyms] [k] __filemap_add_folio

========================= TESTING ======================================

This patch passes libhugetlbfs tests and LTP hugetlb tests

********** TEST SUMMARY
* 2M
* 32-bit 64-bit
* Total testcases: 110 113
* Skipped: 0 0
* PASS: 107 113
* FAIL: 0 0
* Killed by signal: 3 0
* Bad configuration: 0 0
* Expected FAIL: 0 0
* Unexpected PASS: 0 0
* Test not present: 0 0
* Strange test result: 0 0
**********

Done executing testcases.
LTP Version: 20220527-178-g2761a81c4

page migration was also tested using Mike Kravetz's test program.[8]

[dan.carpenter@linaro.org: fix an NULL vs IS_ERR() bug]
Link: https://lkml.kernel.org/r/1772c296-1417-486f-8eef-171af2192681@moroto.mountain
Link: https://lkml.kernel.org/r/20230926192017.98183-1-sidhartha.kumar@oracle.com
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reported-and-tested-by: syzbot+c225dea486da4d5592bd@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=c225dea486da4d5592bd
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
/linux-master/fs/jffs2/
H A Dfs.cdiff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 2f221d6f Thu Jan 21 06:19:26 MST 2021 Christian Brauner <christian.brauner@ubuntu.com> attr: handle idmapped mounts

When file attributes are changed most filesystems rely on the
setattr_prepare(), setattr_copy(), and notify_change() helpers for
initialization and permission checking. Let them handle idmapped mounts.
If the inode is accessed through an idmapped mount map it into the
mount's user namespace. Afterwards the checks are identical to
non-idmapped mounts. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Helpers that perform checks on the ia_uid and ia_gid fields in struct
iattr assume that ia_uid and ia_gid are intended values and have already
been mapped correctly at the userspace-kernelspace boundary as we
already do today. If the initial user namespace is passed nothing
changes so non-idmapped mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
diff 1751e8a6 Mon Nov 27 14:05:09 MST 2017 Linus Torvalds <torvalds@linux-foundation.org> Rename superblock flags (MS_xyz -> SB_xyz)

This is a pure automated search-and-replace of the internal kernel
superblock flags.

The s_flags are now called SB_*, with the names and the values for the
moment mirroring the MS_* flags that they're equivalent to.

Note how the MS_xyz flags are the ones passed to the mount system call,
while the SB_xyz flags are what we then use in sb->s_flags.

The script to do this was:

# places to look in; re security/*: it generally should *not* be
# touched (that stuff parses mount(2) arguments directly), but
# there are two places where we really deal with superblock flags.
FILES="drivers/mtd drivers/staging/lustre fs ipc mm \
include/linux/fs.h include/uapi/linux/bfs_fs.h \
security/apparmor/apparmorfs.c security/apparmor/include/lib.h"
# the list of MS_... constants
SYMS="RDONLY NOSUID NODEV NOEXEC SYNCHRONOUS REMOUNT MANDLOCK \
DIRSYNC NOATIME NODIRATIME BIND MOVE REC VERBOSE SILENT \
POSIXACL UNBINDABLE PRIVATE SLAVE SHARED RELATIME KERNMOUNT \
I_VERSION STRICTATIME LAZYTIME SUBMOUNT NOREMOTELOCK NOSEC BORN \
ACTIVE NOUSER"

SED_PROG=
for i in $SYMS; do SED_PROG="$SED_PROG -e s/MS_$i/SB_$i/g"; done

# we want files that contain at least one of MS_...,
# with fs/namespace.c and fs/pnode.c excluded.
L=$(for i in $SYMS; do git grep -w -l MS_$i $FILES; done| sort|uniq|grep -v '^fs/namespace.c'|grep -v '^fs/pnode.c')

for f in $L; do sed -i $f $SED_PROG; done

Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff 5b825c3a Thu Feb 02 09:54:15 MST 2017 Ingo Molnar <mingo@kernel.org> sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h>

Add #include <linux/cred.h> dependencies to all .c files rely on sched.h
doing that for them.

Note that even if the count where we need to add extra headers seems high,
it's still a net win, because <linux/sched.h> is included in over
2,200 files ...

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff 2b0143b5 Tue Mar 17 16:25:59 MDT 2015 David Howells <dhowells@redhat.com> VFS: normal filesystems (and lustre): d_inode() annotations

that's the bulk of filesystem drivers dealing with inodes of their own

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff 2c27c65e Fri Jun 04 03:30:04 MDT 2010 Christoph Hellwig <hch@lst.de> check ATTR_SIZE contraints in inode_change_ok

Make sure we check the truncate constraints early on in ->setattr by adding
those checks to inode_change_ok. Also clean up and document inode_change_ok
to make this obvious.

As a fallout we don't have to call inode_newsize_ok from simple_setsize and
simplify it down to a truncate_setsize which doesn't return an error. This
simplifies a lot of setattr implementations and means we use truncate_setsize
almost everywhere. Get rid of fat_setsize now that it's trivial and mark
ext2_setsize static to make the calling convention obvious.

Keep the inode_newsize_ok in vmtruncate for now as all callers need an
audit for its removal anyway.

Note: setattr code in ecryptfs doesn't call inode_change_ok at all and
needs a deeper audit, but that is left for later.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff fc0e0197 Sat Sep 01 01:06:03 MDT 2007 Jason Lunz <lunz@falooley.org> [JFFS2] fix write deadlock regression

I've bisected the deadlock when many small appends are done on jffs2 down to
this commit:

commit 6fe6900e1e5b6fa9e5c59aa5061f244fe3f467e2
Author: Nick Piggin <npiggin@suse.de>
Date: Sun May 6 14:49:04 2007 -0700

mm: make read_cache_page synchronous

Ensure pages are uptodate after returning from read_cache_page, which allows
us to cut out most of the filesystem-internal PageUptodate calls.

I didn't have a great look down the call chains, but this appears to fixes 7
possible use-before uptodate in hfs, 2 in hfsplus, 1 in jfs, a few in
ecryptfs, 1 in jffs2, and a possible cleared data overwritten with readpage in
block2mtd. All depending on whether the filler is async and/or can return
with a !uptodate page.

It introduced a wait to read_cache_page, as well as a
read_cache_page_async function equivalent to the old read_cache_page
without any callers.

Switching jffs2_gc_fetch_page to read_cache_page_async for the old
behavior makes the deadlocks go away, but maybe reintroduces the
use-before-uptodate problem? I don't understand the mm/fs interaction
well enough to say.

[It's fine. dwmw2.]

Signed-off-by: Jason Lunz <lunz@falooley.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
diff aa98d7cf Sat May 13 00:09:47 MDT 2006 KaiGai Kohei <kaigai@ak.jp.nec.com> [JFFS2][XATTR] XATTR support on JFFS2 (version. 5)

This attached patches provide xattr support including POSIX-ACL and
SELinux support on JFFS2 (version.5).

There are some significant differences from previous version posted
at last December.
The biggest change is addition of EBS(Erase Block Summary) support.
Currently, both kernel and usermode utility (sumtool) can recognize
xattr nodes which have JFFS2_NODETYPE_XATTR/_XREF nodetype.

In addition, some bugs are fixed.
- A potential race condition was fixed.
- Unexpected fail when updating a xattr by same name/value pair was fixed.
- A bug when removing xattr name/value pair was fixed.

The fundamental structures (such as using two new nodetypes and exclusion
mechanism by rwsem) are unchanged. But most of implementation were reviewed
and updated if necessary.
Espacially, we had to change several internal implementations related to
load_xattr_datum() to avoid a potential race condition.

[1/2] xattr_on_jffs2.kernel.version-5.patch
[2/2] xattr_on_jffs2.utils.version-5.patch

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
diff aa98d7cf Sat May 13 00:09:47 MDT 2006 KaiGai Kohei <kaigai@ak.jp.nec.com> [JFFS2][XATTR] XATTR support on JFFS2 (version. 5)

This attached patches provide xattr support including POSIX-ACL and
SELinux support on JFFS2 (version.5).

There are some significant differences from previous version posted
at last December.
The biggest change is addition of EBS(Erase Block Summary) support.
Currently, both kernel and usermode utility (sumtool) can recognize
xattr nodes which have JFFS2_NODETYPE_XATTR/_XREF nodetype.

In addition, some bugs are fixed.
- A potential race condition was fixed.
- Unexpected fail when updating a xattr by same name/value pair was fixed.
- A bug when removing xattr name/value pair was fixed.

The fundamental structures (such as using two new nodetypes and exclusion
mechanism by rwsem) are unchanged. But most of implementation were reviewed
and updated if necessary.
Espacially, we had to change several internal implementations related to
load_xattr_datum() to avoid a potential race condition.

[1/2] xattr_on_jffs2.kernel.version-5.patch
[2/2] xattr_on_jffs2.utils.version-5.patch

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
diff aa98d7cf Sat May 13 00:09:47 MDT 2006 KaiGai Kohei <kaigai@ak.jp.nec.com> [JFFS2][XATTR] XATTR support on JFFS2 (version. 5)

This attached patches provide xattr support including POSIX-ACL and
SELinux support on JFFS2 (version.5).

There are some significant differences from previous version posted
at last December.
The biggest change is addition of EBS(Erase Block Summary) support.
Currently, both kernel and usermode utility (sumtool) can recognize
xattr nodes which have JFFS2_NODETYPE_XATTR/_XREF nodetype.

In addition, some bugs are fixed.
- A potential race condition was fixed.
- Unexpected fail when updating a xattr by same name/value pair was fixed.
- A bug when removing xattr name/value pair was fixed.

The fundamental structures (such as using two new nodetypes and exclusion
mechanism by rwsem) are unchanged. But most of implementation were reviewed
and updated if necessary.
Espacially, we had to change several internal implementations related to
load_xattr_datum() to avoid a potential race condition.

[1/2] xattr_on_jffs2.kernel.version-5.patch
[2/2] xattr_on_jffs2.utils.version-5.patch

Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

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