nfs: port block device access to files

Link: https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-24-adbd023e19cc@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>

pnfs/blocklayout: Don't add zero-length pnfs_block_dev

We noticed a SCSI device that refused to allow READ CAPACITY when the
device had a PR with exclusive access, registrants only. The result of
this situation is that the blocklayout driver adds a pnfs_block_dev of zero
length which always fails the offset_in_map tests. Instead of continuously
trying to do pNFS for this case, just mark the device as unavailable which
will allow the client to fallback to the MDS for the duration of
PNFS_DEVICE_RETRY_TIMEOUT.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

nfs/blocklayout: Convert to use bdev_open_by_dev/path()

Convert block device handling to use bdev_open_by_dev/path() and pass
the handle around.

CC: linux-nfs@vger.kernel.org
CC: Trond Myklebust <trond.myklebust@hammerspace.com>
CC: Anna Schumaker <anna@kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230927093442.25915-25-jack@suse.cz
Signed-off-by: Christian Brauner <brauner@kernel.org>

nfs/blocklayout: Use the passed in gfp flags

This allocation should use the passed in GFP_ flags instead of
GFP_KERNEL. One places where this matters is in filelayout_pg_init_write()
which uses GFP_NOFS as the allocation flags.

Fixes: 5c83746a0cf2 ("pnfs/blocklayout: in-kernel GETDEVICEINFO XDR parsing")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

block: replace fmode_t with a block-specific type for block open flags

The only overlap between the block open flags mapped into the fmode_t and
other uses of fmode_t are FMODE_READ and FMODE_WRITE. Define a new
blk_mode_t instead for use in blkdev_get_by_{dev,path}, ->open and
->ioctl and stop abusing fmode_t.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jack Wang <jinpu.wang@ionos.com> [rnbd]
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Link: https://lore.kernel.org/r/20230608110258.189493-28-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: use the holder as indication for exclusive opens

The current interface for exclusive opens is rather confusing as it
requires both the FMODE_EXCL flag and a holder. Remove the need to pass
FMODE_EXCL and just key off the exclusive open off a non-NULL holder.

For blkdev_put this requires adding the holder argument, which provides
better debug checking that only the holder actually releases the hold,
but at the same time allows removing the now superfluous mode argument.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Christian Brauner <brauner@kernel.org>
Acked-by: David Sterba <dsterba@suse.com> [btrfs]
Acked-by: Jack Wang <jinpu.wang@ionos.com> [rnbd]
Link: https://lore.kernel.org/r/20230608110258.189493-16-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block: introduce holder ops

Add a new blk_holder_ops structure, which is passed to blkdev_get_by_* and
installed in the block_device for exclusive claims. It will be used to
allow the block layer to call back into the user of the block device for
thing like notification of a removed device or a device resize.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Link: https://lore.kernel.org/r/20230601094459.1350643-10-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nfs/blocklayout: refactor block device opening

Deduplicate the helpers to open a device node by passing a name
prefix argument and using the same helper for both kinds of paths.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

nfs/blocklayout: use bdev_nr_bytes instead of open coding it

Use the proper helper to read the block device size.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20211018101130.1838532-19-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

SUNRPC: Add xdr_set_scratch_page() and xdr_reset_scratch_buffer()

Clean up: De-duplicate some frequently-used code.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

pnfs/blocklayout: off by one in bl_map_stripe()

"dev->nr_children" is the number of children which were parsed
successfully in bl_parse_stripe(). It could be all of them and then, in
that case, it is equal to v->stripe.volumes_count. Either way, the >
should be >= so that we don't go beyond the end of what we're supposed
to.

Fixes: 5c83746a0cf2 ("pnfs/blocklayout: in-kernel GETDEVICEINFO XDR parsing")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org # 3.17+
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

pnfs/blocklayout: handle transient devices

PNFS block/SCSI layouts should gracefully handle cases where block devices
are not available when a layout is retrieved, or the block devices are
removed while the client holds a layout.

While setting up a layout segment, keep a record of an unavailable or
un-parsable block device in cache with a flag so that subsequent layouts do
not spam the server with GETDEVINFO. We can reuse the current
NFS_DEVICEID_UNAVAILABLE handling with one variation: instead of reusing
the device, we will discard it and send a fresh GETDEVINFO after the
timeout, since the lookup and validation of the device occurs within the
GETDEVINFO response handling.

A lookup of a layout segment that references an unavailable device will
return a segment with the NFS_LSEG_UNAVAILABLE flag set. This will allow
the pgio layer to mark the layout with the appropriate fail bit, which
forces subsequent IO to the MDS, and prevents spamming the server with
LAYOUTGET, LAYOUTRETURN.

Finally, when IO to a block device fails, look up the block device(s)
referenced by the pgio header, and mark them as unavailable.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

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>

Fix NULL pointer dereference in bl_free_device().

When bl_parse_deviceid() fails in bl_alloc_deviceid_node() on
blkdev_get_by_*() step we get an pnfs_block_dev struct that is
uninitialized except for bdev field which is set to whatever error
blkdev_get_by_*() returns. bl_free_device() then tries to call
blkdev_put() if bdev is not 0 resulting in a wrong pointer dereference.

Fixing this by setting bdev in struct pnfs_block_dev only if we didn't
get an error from blkdev_get_by_*().

Signed-off-by: Artem Savkov <asavkov@redhat.com>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

nfs/blocklayout: Check max uuids and devices before decoding

Avoid nfs return uuids/devices larger than maximum.

Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

nfs/blocklayout: Make sure calculate signature length aligned

Avoid a bad nfs server return an unaligned length of signature.

Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

nfs/blocklayout: support RH/Fedora dm-mpath device nodes

Instead of reusing the wwn-* names for multipath devices nodes RHEL and
Fedora introduce new dm-mpath-uuid-* nodes with a slightly different
naming scheme. Try these names first to ensure we always get a
multipath-capable device if it exists.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

nfs/blocklayout: refactor open-by-wwn

The current code works with the standard udev/systemd names, but we'll have
to add another method in the next patch. Refactor it into a separate helper
to make room for the new variant.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

nfs/blocklayout: use proper fmode for opening block devices

This was fixed for the original block layout code a while ago, but also
needs to be fixed for the SCSI layout path.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

nfs/blocklayout: add SCSI layout support

This is a trivial extension to the block layout driver to support the
new SCSI layouts draft. There are three changes:

- device identifcation through the SCSI VPD page. This allows us to
directly use the udev generated persistent device names instead of
requiring an expensive lookup by crawling every block device node
in /dev and reading a signature for it.
- use of SCSI persistent reservations to protect device access and
allow for robust fencing. On the client sides this just means
registering and unregistering a server supplied key.
- an optimized LAYOUTCOMMIT payload that doesn't send unessecary
fields to the server.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

pnfs/blocklayout: pass proper file mode to blkdev_get/put

We generally want to read and write to a block device that's used by
the pNFS block layout client (and even if it's read only the server
has no way of telling us). Add FMODE_WRITE to the mode argument
so that we don't incorrectly tell the block driver that we want a
read-only open.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

pnfs/blocklayout: reject too long signatures

Instead of overwriting kernel memory reject too long signatures.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

NFSv4.1: Convert pNFS deviceid to use kfree_rcu()

Use of synchronize_rcu() when unmounting and potentially freeing a lot
of deviceids is problematic. There really is no reason why we can't just
use kfree_rcu() here.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

pnfs/blocklayout: Fix a 64-bit division/remainder issue in bl_map_stripe

kbuild test robot reports:

fs/built-in.o: In function `bl_map_stripe':
>> :(.text+0x965b4): undefined reference to `__aeabi_uldivmod'
>> :(.text+0x965cc): undefined reference to `__aeabi_uldivmod'
>> :(.text+0x96604): undefined reference to `__aeabi_uldivmod'

Fixes: 5c83746a0cf2 (pnfs/blocklayout: in-kernel GETDEVICEINFO XDR parsing)
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

pnfs/blocklayout: in-kernel GETDEVICEINFO XDR parsing

This patches moves parsing of the GETDEVICEINFO XDR to kernel space, as well
as the management of complex devices. The reason for that is we might have
multiple outstanding complex devices after a NOTIFY_DEVICEID4_CHANGE, which
device mapper or md can't handle as they claim devices exclusively.

But as is turns out simple striping / concatenation is fairly trivial to
implement anyway, so we make our life simpler by reducing the reliance
on blkmapd. For now we still use blkmapd by feeding it synthetic SIMPLE
device XDR to translate device signatures to device numbers, but in the
long runs I have plans to eliminate it entirely.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>