ext4: replace read-only check for shutdown check in mmp code

The multi-mount protection kthread checks for read-only filesystem and
aborts in that case. The remount code actually handles stopping of the
kthread on remount so the only purpose of the check is in case of
emergency remount read-only. Replace the check for read-only filesystem
with a check for shutdown filesystem as running MMP on such is risky
anyway and it makes ordering of things during remount simpler.

Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230616165109.21695-11-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

ext4: fix lockdep warning when enabling MMP

When we enable MMP in ext4_multi_mount_protect() during mount or
remount, we end up calling sb_start_write() from write_mmp_block(). This
triggers lockdep warning because freeze protection ranks above s_umount
semaphore we are holding during mount / remount. The problem is harmless
because we are guaranteed the filesystem is not frozen during mount /
remount but still let's fix the warning by not grabbing freeze
protection from ext4_multi_mount_protect().

Cc: stable@kernel.org
Reported-by: syzbot+6b7df7d5506b32467149@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=ab7e5b6f400b7778d46f01841422e5718fb81843
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Link: https://lore.kernel.org/r/20230411121019.21940-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

ext4: reflect error codes from ext4_multi_mount_protect() to its callers

This will allow more fine-grained errno codes to be returned by the
mount system call.

Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

treewide: use get_random_u32_{above,below}() instead of manual loop

These cases were done with this Coccinelle:

@@
expression E;
identifier I;
@@
- do {
... when != I
- I = get_random_u32();
... when != I
- } while (I > E);
+ I = get_random_u32_below(E + 1);

@@
expression E;
identifier I;
@@
- do {
... when != I
- I = get_random_u32();
... when != I
- } while (I >= E);
+ I = get_random_u32_below(E);

@@
expression E;
identifier I;
@@
- do {
... when != I
- I = get_random_u32();
... when != I
- } while (I < E);
+ I = get_random_u32_above(E - 1);

@@
expression E;
identifier I;
@@
- do {
... when != I
- I = get_random_u32();
... when != I
- } while (I <= E);
+ I = get_random_u32_above(E);

@@
identifier I;
@@
- do {
... when != I
- I = get_random_u32();
... when != I
- } while (!I);
+ I = get_random_u32_above(0);

@@
identifier I;
@@
- do {
... when != I
- I = get_random_u32();
... when != I
- } while (I == 0);
+ I = get_random_u32_above(0);

@@
expression E;
@@
- E + 1 + get_random_u32_below(U32_MAX - E)
+ get_random_u32_above(E)

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

treewide: use get_random_u32() when possible

The prandom_u32() function has been a deprecated inline wrapper around
get_random_u32() for several releases now, and compiles down to the
exact same code. Replace the deprecated wrapper with a direct call to
the real function. The same also applies to get_random_int(), which is
just a wrapper around get_random_u32(). This was done as a basic find
and replace.

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: Jan Kara <jack@suse.cz> # for ext4
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk> # for sch_cake
Acked-by: Chuck Lever <chuck.lever@oracle.com> # for nfsd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com> # for thunderbolt
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Acked-by: Helge Deller <deller@gmx.de> # for parisc
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

fs/buffer: Combine two submit_bh() and ll_rw_block() arguments

Both submit_bh() and ll_rw_block() accept a request operation type and
request flags as their first two arguments. Micro-optimize these two
functions by combining these first two arguments into a single argument.
This patch does not change the behavior of any of the modified code.

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jan Kara <jack@suse.cz>
Acked-by: Song Liu <song@kernel.org> (for the md changes)
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220714180729.1065367-48-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: remove bdevname

Replace the remaining calls of bdevname with snprintf using the %pg
format specifier.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220713055317.1888500-10-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

ext4: only initialize mmp_bdevname once

mmp_bdevname is currently both initialized nested inside the kthread_run
call in ext4_multi_mount_protect and in the kmmpd thread started by it.

Lift the initiaization out of the kthread_run call in
ext4_multi_mount_protect, move the BUILD_BUG_ON next to it and remove
the duplicate assignment inside of kmmpd.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220713055317.1888500-9-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

ext4: remove unnecessary type castings

remove unnecessary void* type castings.

Signed-off-by: Yu Zhe <yuzhe@nfschina.com>
Link: https://lore.kernel.org/r/20220401081321.73735-1-yuzhe@nfschina.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

ext4: fix potential uninitialized access to retval in kmmpd

if (!ext4_has_feature_mmp(sb)) then retval can be unitialized before
we jump to the wait_to_exit label.

Fixes: 61bb4a1c417e ("ext4: fix possible UAF when remounting r/o a mmp-protected file system")
Signed-off-by: Ye Bin <yebin10@huawei.com>
Link: https://lore.kernel.org/r/20210713022728.2533770-1-yebin10@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

ext4: fix possible UAF when remounting r/o a mmp-protected file system

After commit 618f003199c6 ("ext4: fix memory leak in
ext4_fill_super"), after the file system is remounted read-only, there
is a race where the kmmpd thread can exit, causing sbi->s_mmp_tsk to
point at freed memory, which the call to ext4_stop_mmpd() can trip
over.

Fix this by only allowing kmmpd() to exit when it is stopped via
ext4_stop_mmpd().

Link: https://lore.kernel.org/r/20210707002433.3719773-1-tytso@mit.edu
Reported-by: Ye Bin <yebin10@huawei.com>
Bug-Report-Link: <20210629143603.2166962-1-yebin10@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>

ext4: fix memory leak in ext4_fill_super

static int kthread(void *_create) will return -ENOMEM
or -EINTR in case of internal failure or
kthread_stop() call happens before threadfn call.

To prevent fancy error checking and make code
more straightforward we moved all cleanup code out
of kmmpd threadfn.

Also, dropped struct mmpd_data at all. Now struct super_block
is a threadfn data and struct buffer_head embedded into
struct ext4_sb_info.

Reported-by: syzbot+d9e482e303930fa4f6ff@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Link: https://lore.kernel.org/r/20210430185046.15742-1-paskripkin@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

ext4: fix ext4_error_err save negative errno into superblock

Fix As write_mmp_block() so that it returns -EIO instead of 1, so that
the correct error gets saved into the superblock.

Cc: stable@kernel.org
Fixes: 54d3adbc29f0 ("ext4: save all error info in save_error_info() and drop ext4_set_errno()")
Reported-by: Liu Zhi Qiang <liuzhiqiang26@huawei.com>
Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Link: https://lore.kernel.org/r/20210406025331.148343-1-yebin10@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

ext4: use common helpers in all places reading metadata buffers

Revome all open codes that read metadata buffers, switch to use
ext4_read_bh_*() common helpers.

Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Suggested-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200924073337.861472-4-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

ext4: save all error info in save_error_info() and drop ext4_set_errno()

Using a separate function, ext4_set_errno() to set the errno is
problematic because it doesn't do the right thing once
s_last_error_errorcode is non-zero. It's also less racy to set all of
the error information all at once. (Also, as a bonus, it shrinks code
size slightly.)

Link: https://lore.kernel.org/r/20200329020404.686965-1-tytso@mit.edu
Fixes: 878520ac45f9 ("ext4: save the error code which triggered...")
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

ext4: don't assume that mmp_nodename/bdevname have NUL

Don't assume that the mmp_nodename and mmp_bdevname strings are NUL
terminated, since they are filled in by snprintf(), which is not
guaranteed to do so.

Link: https://lore.kernel.org/r/1580076215-1048-1-git-send-email-adilger@dilger.ca
Signed-off-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

ext4: save the error code which triggered an ext4_error() in the superblock

This allows the cause of an ext4_error() report to be categorized
based on whether it was triggered due to an I/O error, or an memory
allocation error, or other possible causes. Most errors are caused by
a detected file system inconsistency, so the default code stored in
the superblock will be EXT4_ERR_EFSCORRUPTED.

Link: https://lore.kernel.org/r/20191204032335.7683-1-tytso@mit.edu
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

ext4: don't mark mmp buffer head dirty

Marking mmp bh dirty before writing it will make writeback
pick up mmp block later and submit a write, we don't want the
duplicate write as kmmpd thread should have full control of
reading and writing the mmp block.
Another reason is we will also have random I/O error on
the writeback request when blk integrity is enabled, because
kmmpd could modify the content of the mmp block(e.g. setting
new seq and time) while the mmp block is under I/O requested
by writeback.

Signed-off-by: Li Dongyang <dongyangli@ddn.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Cc: stable@vger.kernel.org

ext4: use 64-bit timestamps for mmp_time

The mmp_time field is 64 bits wide, which is good, but calling
get_seconds() results in a 32-bit value on 32-bit architectures. Using
ktime_get_real_seconds() instead returns 64 bits everywhere.

Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

ext4: clear mmp sequence number when remounting read-only

Previously, when an MMP-protected file system is remounted read-only,
the kmmpd thread would exit the next time it woke up (a few seconds
later), without resetting the MMP sequence number back to
EXT4_MMP_SEQ_CLEAN.

Fix this by explicitly killing the MMP thread when the file system is
remounted read-only.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: Andreas Dilger <adilger@dilger.ca>

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>

ext4: use sizeof(*ptr)

Replace the specification of data structures by pointer dereferences
as the parameter for the operator "sizeof" to make the corresponding size
determination a bit safer according to the Linux coding style convention.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>

VFS: Convert sb->s_flags & MS_RDONLY to sb_rdonly(sb)

Firstly by applying the following with coccinelle's spatch:

@@ expression SB; @@
-SB->s_flags & MS_RDONLY
+sb_rdonly(SB)

to effect the conversion to sb_rdonly(sb), then by applying:

@@ expression A, SB; @@
(
-(!sb_rdonly(SB)) && A
+!sb_rdonly(SB) && A
|
-A != (sb_rdonly(SB))
+A != sb_rdonly(SB)
|
-A == (sb_rdonly(SB))
+A == sb_rdonly(SB)
|
-!(sb_rdonly(SB))
+!sb_rdonly(SB)
|
-A && (sb_rdonly(SB))
+A && sb_rdonly(SB)
|
-A || (sb_rdonly(SB))
+A || sb_rdonly(SB)
|
-(sb_rdonly(SB)) != A
+sb_rdonly(SB) != A
|
-(sb_rdonly(SB)) == A
+sb_rdonly(SB) == A
|
-(sb_rdonly(SB)) && A
+sb_rdonly(SB) && A
|
-(sb_rdonly(SB)) || A
+sb_rdonly(SB) || A
)

@@ expression A, B, SB; @@
(
-(sb_rdonly(SB)) ? 1 : 0
+sb_rdonly(SB)
|
-(sb_rdonly(SB)) ? A : B
+sb_rdonly(SB) ? A : B
)

to remove left over excess bracketage and finally by applying:

@@ expression A, SB; @@
(
-(A & MS_RDONLY) != sb_rdonly(SB)
+(bool)(A & MS_RDONLY) != sb_rdonly(SB)
|
-(A & MS_RDONLY) == sb_rdonly(SB)
+(bool)(A & MS_RDONLY) == sb_rdonly(SB)
)

to make comparisons against the result of sb_rdonly() (which is a bool)
work correctly.

Signed-off-by: David Howells <dhowells@redhat.com>

block,fs: use REQ_* flags directly

Remove the WRITE_* and READ_SYNC wrappers, and just use the flags
directly. Where applicable this also drops usage of the
bio_set_op_attrs wrapper.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

fs: have submit_bh users pass in op and flags separately

This has submit_bh users pass in the operation and flags separately,
so submit_bh_wbc can setup the bio op and bi_rw flags on the bio that
is submitted.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

ext4: remove trailing \n from ext4_warning/ext4_error calls

Messages passed to ext4_warning() or ext4_error() don't need trailing
newlines, because these function add the newlines themselves.

Signed-off-by: Jakub Wilk <jwilk@jwilk.net>

ext4: clean up error handling in the MMP support

There is memory leak as both caller function kmmpd() and callee
read_mmp_block() not releasing bh_check (i.e buffer_head).
Given patch fixes this problem.

[ Additional changes suggested by Andreas Dilger -- TYT ]

Signed-off-by: Jadhav Vikram <vikramjadhavpucsd2007@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

ext4: call out CRC and corruption errors with specific error codes

Instead of overloading EIO for CRC errors and corrupt structures,
return the same error codes that XFS returns for the same issues.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

ext4: silence a format string false positive

Static checkers complain that the format string should be "%s". It does
not make a difference for the current code.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

ext4: simplify some code in read_mmp_block()

My static check complains because we have:

if (!*bh)
return -ENOMEM;
if (*bh) {

The second check is unnecessary.

I've simplified this code by moving the "if (!*bh)" checks around. Also
Andreas Dilger says we should probably print a warning if sb_getblk()
fails.

[ Restructured the code so that we print a warning message as well if
the mmp block doesn't check out, and to print the error code to
disambiguate between the error cases. - TYT ]

Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

ext4: Replace open coded mdata csum feature to helper function

Besides the fact that this replacement improves code readability
it also protects from errors caused direct EXT4_S(sb)->s_es manipulation
which may result attempt to use uninitialized csum machinery.

#Testcase_BEGIN
IMG=/dev/ram0
MNT=/mnt
mkfs.ext4 $IMG
mount $IMG $MNT
#Enable feature directly on disk, on mounted fs
tune2fs -O metadata_csum $IMG
# Provoke metadata update, likey result in OOPS
touch $MNT/test
umount $MNT
#Testcase_END

# Replacement script
@@
expression E;
@@
- EXT4_HAS_RO_COMPAT_FEATURE(E, EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)
+ ext4_has_metadata_csum(E)

https://bugzilla.kernel.org/show_bug.cgi?id=82201

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

ext4: make local functions static

I have been running make namespacecheck to look for unneeded globals, and
found these in ext4.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

ext4: use prandom_u32() instead of get_random_bytes()

Many of the uses of get_random_bytes() do not actually need
cryptographically secure random numbers. Replace those uses with a
call to prandom_u32(), which is faster and which doesn't consume
entropy from the /dev/random driver.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

ext4: mark all metadata I/O with REQ_META

As Dave Chinner pointed out at the 2013 LSF/MM workshop, it's
important that metadata I/O requests are marked as such to avoid
priority inversions caused by I/O bandwidth throttling.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

ext4: fix big-endian bug in metadata checksum calculations

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org

ext4: use unlikely to improve the efficiency of the kernel

Because the function 'sb_getblk' seldomly fails to return NULL
value,it will be better to use 'unlikely' to optimize it.

Signed-off-by: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

ext4: return ENOMEM if sb_getblk() fails

The only reason for sb_getblk() failing is if it can't allocate the
buffer_head. So ENOMEM is more appropriate than EIO. In addition,
make sure that the file system is marked as being inconsistent if
sb_getblk() fails.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org

ext4: Convert to new freezing mechanism

We remove most of frozen checks since upper layer takes care of blocking all
writes. We have to handle protection in ext4_page_mkwrite() in a special way
because we cannot use generic block_page_mkwrite(). Also we add a freeze
protection to ext4_evict_inode() so that iput() of unlinked inode cannot modify
a frozen filesystem (we cannot easily instrument ext4_journal_start() /
ext4_journal_stop() with freeze protection because we are missing the
superblock pointer in ext4_journal_stop() in nojournal mode).

CC: linux-ext4@vger.kernel.org
CC: "Theodore Ts'o" <tytso@mit.edu>
BugLink: https://bugs.launchpad.net/bugs/897421
Tested-by: Kamal Mostafa <kamal@canonical.com>
Tested-by: Peter M. Petrakis <peter.petrakis@canonical.com>
Tested-by: Dann Frazier <dann.frazier@canonical.com>
Tested-by: Massimo Morana <massimo.morana@canonical.com>
Acked-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

ext4: add checksums to the MMP block

Compute and verify a checksum for the MMP block.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

ext4: Fix endianness bug when reading the MMP block

Sparse complained about this endian bug in fs/ext4/mmp.c.

Signed-off-by: Santosh Nayak <santoshprasadnayak@gmail.com>
Reviewed-by: Johann Lombardi <johann@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

ext4: Fix comparison endianness problem in MMP initialization

As part of startup, the MMP initialization code does this:

mmp->mmp_seq = seq = cpu_to_le32(mmp_new_seq());

Next, mmp->mmp_seq is written out to disk, a delay happens, and then
the MMP block is read back in and the sequence value is tested:

if (seq != le32_to_cpu(mmp->mmp_seq)) {
/* fail the mount */

On a LE system such as x86, the *le32* functions do nothing and this
works. Unfortunately, on a BE system such as ppc64, this comparison
becomes:

if (cpu_to_le32(new_seq) != le32_to_cpu(cpu_to_le32(new_seq)) {
/* fail the mount */

Except for a few palindromic sequence numbers, this test always causes
the mount to fail, which makes MMP filesystems generally unmountable
on ppc64. The attached patch fixes this situation.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

ext4: MMP: fix error message rate-limiting logic in kmmpd

Current logic would print an error message only once, and then
'failed_writes' would stay at 1. Rework the loop to increment
'failed_writes' and print the error message every
s_mmp_update_interval * 60 seconds, as intended according to the
comment.

Signed-off-by: Nikitas Angelinas <nikitas_angelinas@xyratex.com>
Signed-off-by: Andrew Perepechko <andrew_perepechko@xyratex.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Acked-by: Andreas Dilger <adilger@dilger.ca>

ext4: MMP: kmmpd should use nodename from init_uts_ns.name, not sysname

sysname holds "Linux" by default, i.e. what appears when doing a "uname
-s"; nodename should be used to print the machine's hostname, i.e. what
is returned when doing a "uname -n" or "hostname", and what
gethostname(2)/sethostname(2) manipulate, in order to notify the
administrator of the node which is contending to mount the filesystem.

Acked-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Nikitas Angelinas <nikitas_angelinas@xyratex.com>
Signed-off-by: Andrew Perepechko <andrew_perepechko@xyratex.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

ext4: add support for multiple mount protection

Prevent an ext4 filesystem from being mounted multiple times.
A sequence number is stored on disk and is periodically updated (every 5
seconds by default) by a mounted filesystem.
At mount time, we now wait for s_mmp_update_interval seconds to make sure
that the MMP sequence does not change.
In case of failure, the nodename, bdevname and the time at which the MMP
block was last updated is displayed.

Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Signed-off-by: Johann Lombardi <johann@whamcloud.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>