Commit Graph

7225 Commits

Author SHA1 Message Date
Linus Torvalds
3bd9dd8138 Bug fixes for 5.17-rc4:
- Only call sync_filesystem when we're remounting the filesystem
    readonly readonly, and actually check its return value.
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Merge tag 'xfs-5.17-fixes-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull xfs fixes from Darrick Wong:
 "Nothing exciting, just more fixes for not returning sync_filesystem
  error values (and eliding it when it's not necessary).

  Summary:

   - Only call sync_filesystem when we're remounting the filesystem
     readonly readonly, and actually check its return value"

* tag 'xfs-5.17-fixes-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: only bother with sync_filesystem during readonly remount
2022-02-26 09:53:19 -08:00
Darrick J. Wong
b97cca3ba9 xfs: only bother with sync_filesystem during readonly remount
In commit 02b9984d64, we pushed a sync_filesystem() call from the VFS
into xfs_fs_remount.  The only time that we ever need to push dirty file
data or metadata to disk for a remount is if we're remounting the
filesystem read only, so this really could be moved to xfs_remount_ro.

Once we've moved the call site, actually check the return value from
sync_filesystem.

Fixes: 02b9984d64 ("fs: push sync_filesystem() down to the file system's remount_fs()")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-02-09 21:07:24 -08:00
Linus Torvalds
fbc04bf01a Fixes for 5.17-rc3:
- Fix fallocate so that it drops all file privileges when files are
    modified instead of open-coding that incompletely.
  - Fix fallocate to flush the log if the caller wanted synchronous file
    updates.
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Merge tag 'xfs-5.17-fixes-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull xfs fixes from Darrick Wong:
 "I was auditing operations in XFS that clear file privileges, and
  realized that XFS' fallocate implementation drops suid/sgid but
  doesn't clear file capabilities the same way that file writes and
  reflink do.

  There are VFS helpers that do it correctly, so refactor XFS to use
  them. I also noticed that we weren't flushing the log at the correct
  point in the fallocate operation, so that's fixed too.

  Summary:

   - Fix fallocate so that it drops all file privileges when files are
     modified instead of open-coding that incompletely.

   - Fix fallocate to flush the log if the caller wanted synchronous
     file updates"

* tag 'xfs-5.17-fixes-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: ensure log flush at the end of a synchronous fallocate call
  xfs: move xfs_update_prealloc_flags() to xfs_pnfs.c
  xfs: set prealloc flag in xfs_alloc_file_space()
  xfs: fallocate() should call file_modified()
  xfs: remove XFS_PREALLOC_SYNC
  xfs: reject crazy array sizes being fed to XFS_IOC_GETBMAP*
2022-02-05 09:21:55 -08:00
Linus Torvalds
ea7b3e6d42 Fixes for 5.17-rc3:
- Fix a bug where callers of ->sync_fs (e.g. sync_filesystem and
    syncfs(2)) ignore the return value.
  - Fix a bug where callers of sync_filesystem (e.g. fs freeze) ignore
    the return value.
  - Fix a bug in XFS where xfs_fs_sync_fs never passed back error
    returns.
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Merge tag 'vfs-5.17-fixes-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull vfs fixes from Darrick Wong:
 "I was auditing the sync_fs code paths recently and noticed that most
  callers of ->sync_fs ignore its return value (and many implementations
  never return nonzero even if the fs is broken!), which means that
  internal fs errors and corruption are not passed up to userspace
  callers of syncfs(2) or FIFREEZE. Hence fixing the common code and
  XFS, and I'll start working on the ext4/btrfs folks if this is merged.

  Summary:

   - Fix a bug where callers of ->sync_fs (e.g. sync_filesystem and
     syncfs(2)) ignore the return value.

   - Fix a bug where callers of sync_filesystem (e.g. fs freeze) ignore
     the return value.

   - Fix a bug in XFS where xfs_fs_sync_fs never passed back error
     returns"

* tag 'vfs-5.17-fixes-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: return errors in xfs_fs_sync_fs
  quota: make dquot_quota_sync return errors from ->sync_fs
  vfs: make sync_filesystem return errors from ->sync_fs
  vfs: make freeze_super abort when sync_filesystem returns error
2022-02-05 09:13:51 -08:00
Dave Chinner
cea267c235 xfs: ensure log flush at the end of a synchronous fallocate call
Since we've started treating fallocate more like a file write, we
should flush the log to disk if the user has asked for synchronous
writes either by setting it via fcntl flags, or inode flags, or with
the sync mount option.  We've already got a helper for this, so use
it.

[The original patch by Darrick was massaged by Dave to fit this patchset]

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2022-02-01 14:14:48 -08:00
Dave Chinner
b39a04636f xfs: move xfs_update_prealloc_flags() to xfs_pnfs.c
The operations that xfs_update_prealloc_flags() perform are now
unique to xfs_fs_map_blocks(), so move xfs_update_prealloc_flags()
to be a static function in xfs_pnfs.c and cut out all the
other functionality that is doesn't use anymore.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2022-02-01 14:14:48 -08:00
Dave Chinner
0b02c8c0d7 xfs: set prealloc flag in xfs_alloc_file_space()
Now that we only call xfs_update_prealloc_flags() from
xfs_file_fallocate() in the case where we need to set the
preallocation flag, do this in xfs_alloc_file_space() where we
already have the inode joined into a transaction and get
rid of the call to xfs_update_prealloc_flags() from the fallocate
code.

This also means that we now correctly avoid setting the
XFS_DIFLAG_PREALLOC flag when xfs_is_always_cow_inode() is true, as
these inodes will never have preallocated extents.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2022-02-01 14:14:48 -08:00
Dave Chinner
fbe7e52003 xfs: fallocate() should call file_modified()
In XFS, we always update the inode change and modification time when
any fallocate() operation succeeds.  Furthermore, as various
fallocate modes can change the file contents (extending EOF,
punching holes, zeroing things, shifting extents), we should drop
file privileges like suid just like we do for a regular write().
There's already a VFS helper that figures all this out for us, so
use that.

The net effect of this is that we no longer drop suid/sgid if the
caller is root, but we also now drop file capabilities.

We also move the xfs_update_prealloc_flags() function so that it now
is only called by the scope that needs to set the the prealloc flag.

Based on a patch from Darrick Wong.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2022-02-01 14:14:48 -08:00
Dave Chinner
472c6e46f5 xfs: remove XFS_PREALLOC_SYNC
Callers can acheive the same thing by calling xfs_log_force_inode()
after making their modifications. There is no need for
xfs_update_prealloc_flags() to do this.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2022-02-01 14:14:48 -08:00
Darrick J. Wong
29d650f7e3 xfs: reject crazy array sizes being fed to XFS_IOC_GETBMAP*
Syzbot tripped over the following complaint from the kernel:

WARNING: CPU: 2 PID: 15402 at mm/util.c:597 kvmalloc_node+0x11e/0x125 mm/util.c:597

While trying to run XFS_IOC_GETBMAP against the following structure:

struct getbmap fubar = {
	.bmv_count	= 0x22dae649,
};

Obviously, this is a crazy huge value since the next thing that the
ioctl would do is allocate 37GB of memory.  This is enough to make
kvmalloc mad, but isn't large enough to trip the validation functions.
In other words, I'm fussing with checks that were **already sufficient**
because that's easier than dealing with 644 internal bug reports.  Yes,
that's right, six hundred and forty-four.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Catherine Hoang <catherine.hoang@oracle.com>
2022-01-31 13:20:58 -08:00
Darrick J. Wong
2d86293c70 xfs: return errors in xfs_fs_sync_fs
Now that the VFS will do something with the return values from
->sync_fs, make ours pass on error codes.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christian Brauner <brauner@kernel.org>
2022-01-30 08:59:47 -08:00
Dave Chinner
ebb7fb1557 xfs, iomap: limit individual ioend chain lengths in writeback
Trond Myklebust reported soft lockups in XFS IO completion such as
this:

 watchdog: BUG: soft lockup - CPU#12 stuck for 23s! [kworker/12:1:3106]
 CPU: 12 PID: 3106 Comm: kworker/12:1 Not tainted 4.18.0-305.10.2.el8_4.x86_64 #1
 Workqueue: xfs-conv/md127 xfs_end_io [xfs]
 RIP: 0010:_raw_spin_unlock_irqrestore+0x11/0x20
 Call Trace:
  wake_up_page_bit+0x8a/0x110
  iomap_finish_ioend+0xd7/0x1c0
  iomap_finish_ioends+0x7f/0xb0
  xfs_end_ioend+0x6b/0x100 [xfs]
  xfs_end_io+0xb9/0xe0 [xfs]
  process_one_work+0x1a7/0x360
  worker_thread+0x1fa/0x390
  kthread+0x116/0x130
  ret_from_fork+0x35/0x40

Ioends are processed as an atomic completion unit when all the
chained bios in the ioend have completed their IO. Logically
contiguous ioends can also be merged and completed as a single,
larger unit.  Both of these things can be problematic as both the
bio chains per ioend and the size of the merged ioends processed as
a single completion are both unbound.

If we have a large sequential dirty region in the page cache,
write_cache_pages() will keep feeding us sequential pages and we
will keep mapping them into ioends and bios until we get a dirty
page at a non-sequential file offset. These large sequential runs
can will result in bio and ioend chaining to optimise the io
patterns. The pages iunder writeback are pinned within these chains
until the submission chaining is broken, allowing the entire chain
to be completed. This can result in huge chains being processed
in IO completion context.

We get deep bio chaining if we have large contiguous physical
extents. We will keep adding pages to the current bio until it is
full, then we'll chain a new bio to keep adding pages for writeback.
Hence we can build bio chains that map millions of pages and tens of
gigabytes of RAM if the page cache contains big enough contiguous
dirty file regions. This long bio chain pins those pages until the
final bio in the chain completes and the ioend can iterate all the
chained bios and complete them.

OTOH, if we have a physically fragmented file, we end up submitting
one ioend per physical fragment that each have a small bio or bio
chain attached to them. We do not chain these at IO submission time,
but instead we chain them at completion time based on file
offset via iomap_ioend_try_merge(). Hence we can end up with unbound
ioend chains being built via completion merging.

XFS can then do COW remapping or unwritten extent conversion on that
merged chain, which involves walking an extent fragment at a time
and running a transaction to modify the physical extent information.
IOWs, we merge all the discontiguous ioends together into a
contiguous file range, only to then process them individually as
discontiguous extents.

This extent manipulation is computationally expensive and can run in
a tight loop, so merging logically contiguous but physically
discontigous ioends gains us nothing except for hiding the fact the
fact we broke the ioends up into individual physical extents at
submission and then need to loop over those individual physical
extents at completion.

Hence we need to have mechanisms to limit ioend sizes and
to break up completion processing of large merged ioend chains:

1. bio chains per ioend need to be bound in length. Pure overwrites
go straight to iomap_finish_ioend() in softirq context with the
exact bio chain attached to the ioend by submission. Hence the only
way to prevent long holdoffs here is to bound ioend submission
sizes because we can't reschedule in softirq context.

2. iomap_finish_ioends() has to handle unbound merged ioend chains
correctly. This relies on any one call to iomap_finish_ioend() being
bound in runtime so that cond_resched() can be issued regularly as
the long ioend chain is processed. i.e. this relies on mechanism #1
to limit individual ioend sizes to work correctly.

3. filesystems have to loop over the merged ioends to process
physical extent manipulations. This means they can loop internally,
and so we break merging at physical extent boundaries so the
filesystem can easily insert reschedule points between individual
extent manipulations.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reported-and-tested-by: Trond Myklebust <trondmy@hammerspace.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2022-01-26 09:19:20 -08:00
Linus Torvalds
1cb69c8044 New code for 5.17:
- Minor cleanup of ioctl32 cruft
 - Clean up open coded inodegc workqueue function calls
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Merge tag 'xfs-5.17-merge-7' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull xfs fixes from Darrick Wong:
 "One of the patches removes some dead code from xfs_ioctl32.h and the
  other fixes broken workqueue flushing in the inode garbage collector.

   - Minor cleanup of ioctl32 cruft

   - Clean up open coded inodegc workqueue function calls"

* tag 'xfs-5.17-merge-7' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: flush inodegc workqueue tasks before cancel
  xfs: remove unused xfs_ioctl32.h declarations
2022-01-22 11:04:27 +02:00
Linus Torvalds
31d949782e Withdraw the XFS_IOC_ALLOCSP* and XFS_IOC_FREESP* ioctl definitions.
Remove the header definitions for these ioctls.  The just-removed
 implementation has allowed callers to read stale disk contents for more
 than **21 years** and nobody noticed or complained, which implies a lack
 of users aside from exploit programs.
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Merge tag 'xfs-5.17-merge-6' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull more xfs irix ioctl housecleaning from Darrick Wong:
 "Withdraw the XFS_IOC_ALLOCSP* and XFS_IOC_FREESP* ioctl definitions.

  This is the third and final of a series of small pull requests that
  perform some long overdue housecleaning of XFS ioctls. This time,
  we're withdrawing all variants of the ALLOCSP and FREESP ioctls from
  XFS' userspace API. This might be a little premature since we've only
  just removed the functionality, but as I pointed out in the last pull
  request, nobody (including fstests) noticed that it was broken for 20
  years.

  In response to the patch, we received a single comment from someone
  who stated that they 'augment' the ioctl for their own purposes, but
  otherwise acquiesced to the withdrawal. I still want to try to clobber
  these old ioctl definitions in 5.17.

  So remove the header definitions for these ioctls. The just-removed
  implementation has allowed callers to read stale disk contents for
  more than **21 years** and nobody noticed or complained, which implies
  a lack of users aside from exploit programs"

* tag 'xfs-5.17-merge-6' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: remove the XFS_IOC_{ALLOC,FREE}SP* definitions
2022-01-21 08:51:48 +02:00
Linus Torvalds
d701a8ccac Remove the XFS_IOC_ALLOCSP* and XFS_IOC_FREESP* ioctl families.
Linux has always used fallocate as the space management system call,
 whereas these Irix legacy ioctls only ever worked on XFS, and have been
 the cause of recent stale data disclosure vulnerabilities.  As
 equivalent functionality is available elsewhere, remove the code.
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Merge tag 'xfs-5.17-merge-5' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull xfs irix ioctl housecleaning from Darrick Wong:
 "Remove the XFS_IOC_ALLOCSP* and XFS_IOC_FREESP* ioctl families.

  This is the second of a series of small pull requests that perform
  some long overdue housecleaning of XFS ioctls. This time, we're
  vacating the implementation of all variants of the ALLOCSP and FREESP
  ioctls, which are holdovers from EFS in Irix, circa 1993. Roughly
  equivalent functionality have been available for both ioctls since
  2.6.25 (April 2008):

   - XFS_IOC_FREESP ftruncates a file.

   - XFS_IOC_ALLOCSP is the equivalent of fallocate.

  As noted in the fix patch for CVE 2021-4155, the ALLOCSP ioctl has
  been serving up stale disk blocks since 2000, and in 21 years
  **nobody** noticed. On those grounds I think it's safe to vacate the
  implementation.

  Note that we lose the ability to preallocate and truncate relative to
  the current file position, but as nobody's ever implemented that for
  the VFS, I conclude that it's not in high demand.

  Linux has always used fallocate as the space management system call,
  whereas these Irix legacy ioctls only ever worked on XFS, and have
  been the cause of recent stale data disclosure vulnerabilities. As
  equivalent functionality is available elsewhere, remove the code"

* tag 'xfs-5.17-merge-5' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: kill the XFS_IOC_{ALLOC,FREE}SP* ioctls
2022-01-21 08:47:25 +02:00
Linus Torvalds
12a8fb20f1 Withdraw the ioctl definition for the FSSETDM ioctl.
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Merge tag 'xfs-5.17-merge-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull xfs ioctl housecleaning from Darrick Wong:
 "This is the first of a series of small pull requests that perform some
  long overdue housecleaning of XFS ioctls. This first pull request
  removes the FSSETDM ioctl, which was used to set DMAPI event
  attributes on XFS files. The DMAPI support has never been merged
  upstream and the implementation of FSSETDM itself was removed two
  years ago, so let's withdraw it completely.

   - Withdraw the ioctl definition for the FSSETDM ioctl"

* tag 'xfs-5.17-merge-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: remove the XFS_IOC_FSSETDM definitions
2022-01-21 08:44:07 +02:00
Brian Foster
6191cf3ad5 xfs: flush inodegc workqueue tasks before cancel
The xfs_inodegc_stop() helper performs a high level flush of pending
work on the percpu queues and then runs a cancel_work_sync() on each
of the percpu work tasks to ensure all work has completed before
returning.  While cancel_work_sync() waits for wq tasks to complete,
it does not guarantee work tasks have started. This means that the
_stop() helper can queue and instantly cancel a wq task without
having completed the associated work. This can be observed by
tracepoint inspection of a simple "rm -f <file>; fsfreeze -f <mnt>"
test:

	xfs_destroy_inode: ... ino 0x83 ...
	xfs_inode_set_need_inactive: ... ino 0x83 ...
	xfs_inodegc_stop: ...
	...
	xfs_inodegc_start: ...
	xfs_inodegc_worker: ...
	xfs_inode_inactivating: ... ino 0x83 ...

The first few lines show that the inode is removed and need inactive
state set, but the inactivation work has not completed before the
inodegc mechanism stops. The inactivation doesn't actually occur
until the fs is unfrozen and the gc mechanism starts back up. Note
that this test requires fsfreeze to reproduce because xfs_freeze
indirectly invokes xfs_fs_statfs(), which calls xfs_inodegc_flush().

When this occurs, the workqueue try_to_grab_pending() logic first
tries to steal the pending bit, which does not succeed because the
bit has been set by queue_work_on(). Subsequently, it checks for
association of a pool workqueue from the work item under the pool
lock. This association is set at the point a work item is queued and
cleared when dequeued for processing. If the association exists, the
work item is removed from the queue and cancel_work_sync() returns
true. If the pwq association is cleared, the remove attempt assumes
the task is busy and retries (eventually returning false to the
caller after waiting for the work task to complete).

To avoid this race, we can flush each work item explicitly before
cancel. However, since the _queue_all() already schedules each
underlying work item, the workqueue level helpers are sufficient to
achieve the same ordering effect. E.g., the inodegc enabled flag
prevents scheduling any further work in the _stop() case. Use the
drain_workqueue() helper in this particular case to make the intent
a bit more self explanatory.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-01-19 14:58:26 -08:00
Darrick J. Wong
a8e422af69 xfs: remove unused xfs_ioctl32.h declarations
Remove these unused ia32 compat declarations; all the bits involved have
either been withdrawn or hoisted to the VFS.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
2022-01-18 10:18:36 -08:00
Darrick J. Wong
b3bb9413e7 xfs: remove the XFS_IOC_{ALLOC,FREE}SP* definitions
Now that we've made these ioctls defunct, move them from xfs_fs.h to
xfs_ioctl.c, which effectively removes them from the publicly supported
ioctl interfaces for XFS.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
2022-01-17 09:17:11 -08:00
Darrick J. Wong
4d1b97f9ce xfs: kill the XFS_IOC_{ALLOC,FREE}SP* ioctls
According to the glibc compat header for Irix 4, these ioctls originated
in April 1991 as a (somewhat clunky) way to preallocate space at the end
of a file on an EFS filesystem.  XFS, which was released in Irix 5.3 in
December 1993, picked up these ioctls to maintain compatibility and they
were ported to Linux in the early 2000s.

Recently it was pointed out to me they still lurk in the kernel, even
though the Linux fallocate syscall supplanted the functionality a long
time ago.  fstests doesn't seem to include any real functional or stress
tests for these ioctls, which means that the code quality is ... very
questionable.  Most notably, it was a stale disk block exposure vector
for 21 years and nobody noticed or complained.  As mature programmers
say, "If you're not testing it, it's broken."

Given all that, let's withdraw these ioctls from the XFS userspace API.
Normally we'd set a long deprecation process, but I estimate that there
aren't any real users, so let's trigger a warning in dmesg and return
-ENOTTY.

See: CVE-2021-4155

Augments: 983d8e60f5 ("xfs: map unwritten blocks in XFS_IOC_{ALLOC,FREE}SP just like fallocate")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-01-17 09:16:41 -08:00
Darrick J. Wong
9dec0368b9 xfs: remove the XFS_IOC_FSSETDM definitions
Remove the definitions for these ioctls, since the functionality (and,
weirdly, the 32-bit compat ioctl definitions) were removed from the
kernel in November 2019.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-01-17 09:16:40 -08:00
Linus Torvalds
f56caedaf9 Merge branch 'akpm' (patches from Andrew)
Merge misc updates from Andrew Morton:
 "146 patches.

  Subsystems affected by this patch series: kthread, ia64, scripts,
  ntfs, squashfs, ocfs2, vfs, and mm (slab-generic, slab, kmemleak,
  dax, kasan, debug, pagecache, gup, shmem, frontswap, memremap,
  memcg, selftests, pagemap, dma, vmalloc, memory-failure, hugetlb,
  userfaultfd, vmscan, mempolicy, oom-kill, hugetlbfs, migration, thp,
  ksm, page-poison, percpu, rmap, zswap, zram, cleanups, hmm, and
  damon)"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (146 commits)
  mm/damon: hide kernel pointer from tracepoint event
  mm/damon/vaddr: hide kernel pointer from damon_va_three_regions() failure log
  mm/damon/vaddr: use pr_debug() for damon_va_three_regions() failure logging
  mm/damon/dbgfs: remove an unnecessary variable
  mm/damon: move the implementation of damon_insert_region to damon.h
  mm/damon: add access checking for hugetlb pages
  Docs/admin-guide/mm/damon/usage: update for schemes statistics
  mm/damon/dbgfs: support all DAMOS stats
  Docs/admin-guide/mm/damon/reclaim: document statistics parameters
  mm/damon/reclaim: provide reclamation statistics
  mm/damon/schemes: account how many times quota limit has exceeded
  mm/damon/schemes: account scheme actions that successfully applied
  mm/damon: remove a mistakenly added comment for a future feature
  Docs/admin-guide/mm/damon/usage: update for kdamond_pid and (mk|rm)_contexts
  Docs/admin-guide/mm/damon/usage: mention tracepoint at the beginning
  Docs/admin-guide/mm/damon/usage: remove redundant information
  Docs/admin-guide/mm/damon/usage: update for scheme quotas and watermarks
  mm/damon: convert macro functions to static inline functions
  mm/damon: modify damon_rand() macro to static inline function
  mm/damon: move damon_rand() definition into damon.h
  ...
2022-01-15 20:37:06 +02:00
NeilBrown
4034247a0d mm: introduce memalloc_retry_wait()
Various places in the kernel - largely in filesystems - respond to a
memory allocation failure by looping around and re-trying.  Some of
these cannot conveniently use __GFP_NOFAIL, for reasons such as:

 - a GFP_ATOMIC allocation, which __GFP_NOFAIL doesn't work on
 - a need to check for the process being signalled between failures
 - the possibility that other recovery actions could be performed
 - the allocation is quite deep in support code, and passing down an
   extra flag to say if __GFP_NOFAIL is wanted would be clumsy.

Many of these currently use congestion_wait() which (in almost all
cases) simply waits the given timeout - congestion isn't tracked for
most devices.

It isn't clear what the best delay is for loops, but it is clear that
the various filesystems shouldn't be responsible for choosing a timeout.

This patch introduces memalloc_retry_wait() with takes on that
responsibility.  Code that wants to retry a memory allocation can call
this function passing the GFP flags that were used.  It will wait
however is appropriate.

For now, it only considers __GFP_NORETRY and whatever
gfpflags_allow_blocking() tests.  If blocking is allowed without
__GFP_NORETRY, then alloc_page either made some reclaim progress, or
waited for a while, before failing.  So there is no need for much
further waiting.  memalloc_retry_wait() will wait until the current
jiffie ends.  If this condition is not met, then alloc_page() won't have
waited much if at all.  In that case memalloc_retry_wait() waits about
200ms.  This is the delay that most current loops uses.

linux/sched/mm.h needs to be included in some files now,
but linux/backing-dev.h does not.

Link: https://lkml.kernel.org/r/163754371968.13692.1277530886009912421@noble.neil.brown.name
Signed-off-by: NeilBrown <neilb@suse.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Chao Yu <chao@kernel.org>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-01-15 16:30:29 +02:00
Linus Torvalds
a33f5c380c New code for 5.17:
- Fix a minor locking inconsistency in readdir
  - Fix incorrect fs feature bit validation for secondary superblocks
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Merge tag 'xfs-5.17-merge-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull xfs fixes from Darrick Wong:
 "These are the last few obvious fixes that I found while stress testing
  online fsck for XFS prior to initiating a design review of the whole
  giant machinery.

   - Fix a minor locking inconsistency in readdir

   - Fix incorrect fs feature bit validation for secondary superblocks"

* tag 'xfs-5.17-merge-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: fix online fsck handling of v5 feature bits on secondary supers
  xfs: take the ILOCK when readdir inspects directory mapping data
2022-01-15 07:47:40 +02:00
Linus Torvalds
3acbdbf42e dax + libnvdimm for v5.17
- Simplify the dax_operations API
   - Eliminate bdev_dax_pgoff() in favor of the filesystem maintaining
     and applying a partition offset to all its DAX iomap operations.
   - Remove wrappers and device-mapper stacked callbacks for
     ->copy_from_iter() and ->copy_to_iter() in favor of moving
     block_device relative offset responsibility to the
     dax_direct_access() caller.
   - Remove the need for an @bdev in filesystem-DAX infrastructure
   - Remove unused uio helpers copy_from_iter_flushcache() and
     copy_mc_to_iter() as only the non-check_copy_size() versions are
     used for DAX.
 - Prepare XFS for the pending (next merge window) DAX+reflink support
 - Remove deprecated DEV_DAX_PMEM_COMPAT support
 - Cleanup a straggling misuse of the GUID api
 
 Tags offered after the branch was cut:
 Reviewed-by: Mike Snitzer <snitzer@redhat.com>
 Link: https://lore.kernel.org/r/Ydb/3P+8nvjCjYfO@redhat.com
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Merge tag 'libnvdimm-for-5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull dax and libnvdimm updates from Dan Williams:
 "The bulk of this is a rework of the dax_operations API after
  discovering the obstacles it posed to the work-in-progress DAX+reflink
  support for XFS and other copy-on-write filesystem mechanics.

  Primarily the need to plumb a block_device through the API to handle
  partition offsets was a sticking point and Christoph untangled that
  dependency in addition to other cleanups to make landing the
  DAX+reflink support easier.

  The DAX_PMEM_COMPAT option has been around for 4 years and not only
  are distributions shipping userspace that understand the current
  configuration API, but some are not even bothering to turn this option
  on anymore, so it seems a good time to remove it per the deprecation
  schedule. Recall that this was added after the device-dax subsystem
  moved from /sys/class/dax to /sys/bus/dax for its sysfs organization.
  All recent functionality depends on /sys/bus/dax.

  Some other miscellaneous cleanups and reflink prep patches are
  included as well.

  Summary:

   - Simplify the dax_operations API:

      - Eliminate bdev_dax_pgoff() in favor of the filesystem
        maintaining and applying a partition offset to all its DAX iomap
        operations.

      - Remove wrappers and device-mapper stacked callbacks for
        ->copy_from_iter() and ->copy_to_iter() in favor of moving
        block_device relative offset responsibility to the
        dax_direct_access() caller.

      - Remove the need for an @bdev in filesystem-DAX infrastructure

      - Remove unused uio helpers copy_from_iter_flushcache() and
        copy_mc_to_iter() as only the non-check_copy_size() versions are
        used for DAX.

   - Prepare XFS for the pending (next merge window) DAX+reflink support

   - Remove deprecated DEV_DAX_PMEM_COMPAT support

   - Cleanup a straggling misuse of the GUID api"

* tag 'libnvdimm-for-5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (38 commits)
  iomap: Fix error handling in iomap_zero_iter()
  ACPI: NFIT: Import GUID before use
  dax: remove the copy_from_iter and copy_to_iter methods
  dax: remove the DAXDEV_F_SYNC flag
  dax: simplify dax_synchronous and set_dax_synchronous
  uio: remove copy_from_iter_flushcache() and copy_mc_to_iter()
  iomap: turn the byte variable in iomap_zero_iter into a ssize_t
  memremap: remove support for external pgmap refcounts
  fsdax: don't require CONFIG_BLOCK
  iomap: build the block based code conditionally
  dax: fix up some of the block device related ifdefs
  fsdax: shift partition offset handling into the file systems
  dax: return the partition offset from fs_dax_get_by_bdev
  iomap: add a IOMAP_DAX flag
  xfs: pass the mapping flags to xfs_bmbt_to_iomap
  xfs: use xfs_direct_write_iomap_ops for DAX zeroing
  xfs: move dax device handling into xfs_{alloc,free}_buftarg
  ext4: cleanup the dax handling in ext4_fill_super
  ext2: cleanup the dax handling in ext2_fill_super
  fsdax: decouple zeroing from the iomap buffered I/O code
  ...
2022-01-12 15:46:11 -08:00
Linus Torvalds
f079ab01b5 Convert xfs/iomap to use folios
This should be all that is needed for XFS to use large folios.
 There is no code in this pull request to create large folios, but
 no additional changes should be needed to XFS or iomap once they
 are created.
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Merge tag 'iomap-5.17' of git://git.infradead.org/users/willy/linux

Pull iomap updates from Matthew Wilcox:
 "Convert xfs/iomap to use folios.

  This should be all that is needed for XFS to use large folios. There
  is no code in this pull request to create large folios, but no
  additional changes should be needed to XFS or iomap once they are
  created.

  Usually this would have come from Darrick, and we had intended that it
  would come that route. Between the holidays and various things which
  Darrick needed to work on, he asked if I could send things directly.

  There weren't any other iomap patches pending for this release, which
  probably also played a role"

* tag 'iomap-5.17' of git://git.infradead.org/users/willy/linux: (26 commits)
  iomap: Inline __iomap_zero_iter into its caller
  xfs: Support large folios
  iomap: Support large folios in invalidatepage
  iomap: Convert iomap_migrate_page() to use folios
  iomap: Convert iomap_add_to_ioend() to take a folio
  iomap: Simplify iomap_do_writepage()
  iomap: Simplify iomap_writepage_map()
  iomap,xfs: Convert ->discard_page to ->discard_folio
  iomap: Convert iomap_write_end_inline to take a folio
  iomap: Convert iomap_write_begin() and iomap_write_end() to folios
  iomap: Convert __iomap_zero_iter to use a folio
  iomap: Allow iomap_write_begin() to be called with the full length
  iomap: Convert iomap_page_mkwrite to use a folio
  iomap: Convert readahead and readpage to use a folio
  iomap: Convert iomap_read_inline_data to take a folio
  iomap: Use folio offsets instead of page offsets
  iomap: Convert bio completions to use folios
  iomap: Pass the iomap_page into iomap_set_range_uptodate
  iomap: Add iomap_invalidate_folio
  iomap: Convert iomap_releasepage to use a folio
  ...
2022-01-12 12:51:41 -08:00
Darrick J. Wong
4a9bca8680 xfs: fix online fsck handling of v5 feature bits on secondary supers
While I was auditing the code in xfs_repair that adds feature bits to
existing V5 filesystems, I decided to have a look at how online fsck
handles feature bits, and I found a few problems:

1) ATTR2 is added to the primary super when an xattr is set to a file,
but that isn't consistently propagated to secondary supers.  This isn't
a corruption, merely a discrepancy that repair will fix if it ever has
to restore the primary from a secondary.  Hence, if we find a mismatch
on a secondary, this is a preen condition, not a corruption.

2) There are more compat and ro_compat features now than there used to
be, but we mask off the newer features from testing.  This means we
ignore inconsistencies in the INOBTCOUNT and BIGTIME features, which is
wrong.  Get rid of the masking and compare directly.

3) NEEDSREPAIR, when set on a secondary, is ignored by everyone.  Hence
a mismatch here should also be flagged for preening, and online repair
should clear the flag.  Right now we ignore it due to (2).

4) log_incompat features are ephemeral, since we can clear the feature
bit as soon as the log no longer contains live records for a particular
log feature.  As such, the only copy we care about is the one in the
primary super.  If we find any bits set in the secondary super, we
should flag that for preening, and clear the bits if the user elects to
repair it.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-01-12 09:45:21 -08:00
Darrick J. Wong
65552b02a1 xfs: take the ILOCK when readdir inspects directory mapping data
I was poking around in the directory code while diagnosing online fsck
bugs, and noticed that xfs_readdir doesn't actually take the directory
ILOCK when it calls xfs_dir2_isblock.  xfs_dir_open most probably loaded
the data fork mappings and the VFS took i_rwsem (aka IOLOCK_SHARED) so
we're protected against writer threads, but we really need to follow the
locking model like we do in other places.

To avoid unnecessarily cycling the ILOCK for fairly small directories,
change the block/leaf _getdents functions to consume the ILOCK hold that
the parent readdir function took to decide on a _getdents implementation.

It is ok to cycle the ILOCK in readdir because the VFS takes the IOLOCK
in the appropriate mode during lookups and writes, and we don't want to
be holding the ILOCK when we copy directory entries to userspace in case
there's a page fault.  We really only need it to protect against data
fork lookups, like we do for other files.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-01-11 15:11:04 -08:00
Linus Torvalds
11fc88c2e4 New code for 5.17:
- Fix log recovery with da btree buffers when metauuid is in use.
  - Fix type coercion problems in xattr buffer size validation.
  - Fix a bug in online scrub dir leaf bestcount checking.
  - Only run COW recovery when recovering the log.
  - Fix symlink target buffer UAF problems and symlink locking problems
    by not exposing xfs innards to the VFS.
  - Fix incorrect quotaoff lock usage.
  - Don't let transactions cancel cleanly if they have deferred work
    items attached.
  - Fix a UAF when we're deciding if we need to relog an intent item.
  - Reduce kvmalloc overhead for log shadow buffers.
  - Clean up sysfs attr group usage.
  - Fix a bug where scrub's bmap/rmap checking could race with a quota
    file block allocation due to insufficient locking.
  - Teach scrub to complain about invalid project ids.
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Merge tag 'xfs-5.17-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull xfs updates from Darrick Wong:
 "The big new feature here is that the mount code now only bothers to
  try to free stale COW staging extents if the fs unmounted uncleanly.
  This should reduce mount times, particularly on filesystems supporting
  reflink and containing a large number of allocation groups.

  Everything else this cycle are bugfixes, as the iomap folios
  conversion should be plenty enough excitement for anyone. That and I
  ran out of brain bandwidth after Thanksgiving last year.

  Summary:

   - Fix log recovery with da btree buffers when metauuid is in use.

   - Fix type coercion problems in xattr buffer size validation.

   - Fix a bug in online scrub dir leaf bestcount checking.

   - Only run COW recovery when recovering the log.

   - Fix symlink target buffer UAF problems and symlink locking problems
     by not exposing xfs innards to the VFS.

   - Fix incorrect quotaoff lock usage.

   - Don't let transactions cancel cleanly if they have deferred work
     items attached.

   - Fix a UAF when we're deciding if we need to relog an intent item.

   - Reduce kvmalloc overhead for log shadow buffers.

   - Clean up sysfs attr group usage.

   - Fix a bug where scrub's bmap/rmap checking could race with a quota
     file block allocation due to insufficient locking.

   - Teach scrub to complain about invalid project ids"

* tag 'xfs-5.17-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: warn about inodes with project id of -1
  xfs: hold quota inode ILOCK_EXCL until the end of dqalloc
  xfs: Remove redundant assignment of mp
  xfs: reduce kvmalloc overhead for CIL shadow buffers
  xfs: sysfs: use default_groups in kobj_type
  xfs: prevent UAF in xfs_log_item_in_current_chkpt
  xfs: prevent a WARN_ONCE() in xfs_ioc_attr_list()
  xfs: Fix comments mentioning xfs_ialloc
  xfs: check sb_meta_uuid for dabuf buffer recovery
  xfs: fix a bug in the online fsck directory leaf1 bestcount check
  xfs: only run COW extent recovery when there are no live extents
  xfs: don't expose internal symlink metadata buffers to the vfs
  xfs: fix quotaoff mutex usage now that we don't support disabling it
  xfs: shut down filesystem if we xfs_trans_cancel with deferred work items
2022-01-11 15:01:50 -08:00
Linus Torvalds
5dfbfe71e3 fs.idmapped.v5.17
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Merge tag 'fs.idmapped.v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux

Pull fs idmapping updates from Christian Brauner:
 "This contains the work to enable the idmapping infrastructure to
  support idmapped mounts of filesystems mounted with an idmapping.

  In addition this contains various cleanups that avoid repeated
  open-coding of the same functionality and simplify the code in quite a
  few places.

  We also finish the renaming of the mapping helpers we started a few
  kernel releases back and move them to a dedicated header to not
  continue polluting the fs header needlessly with low-level idmapping
  helpers. With this series the fs header only contains idmapping
  helpers that interact with fs objects.

  Currently we only support idmapped mounts for filesystems mounted
  without an idmapping themselves. This was a conscious decision
  mentioned in multiple places (cf. [1]).

  As explained at length in [3] it is perfectly fine to extend support
  for idmapped mounts to filesystem's mounted with an idmapping should
  the need arise. The need has been there for some time now (cf. [2]).

  Before we can port any filesystem that is mountable with an idmapping
  to support idmapped mounts in the coming cycles, we need to first
  extend the mapping helpers to account for the filesystem's idmapping.
  This again, is explained at length in our documentation at [3] and
  also in the individual commit messages so here's an overview.

  Currently, the low-level mapping helpers implement the remapping
  algorithms described in [3] in a simplified manner as we could rely on
  the fact that all filesystems supporting idmapped mounts are mounted
  without an idmapping.

  In contrast, filesystems mounted with an idmapping are very likely to
  not use an identity mapping and will instead use a non-identity
  mapping. So the translation step from or into the filesystem's
  idmapping in the remapping algorithm cannot be skipped for such
  filesystems.

  Non-idmapped filesystems and filesystems not supporting idmapped
  mounts are unaffected by this change as the remapping algorithms can
  take the same shortcut as before. If the low-level helpers detect that
  they are dealing with an idmapped mount but the underlying filesystem
  is mounted without an idmapping we can rely on the previous shortcut
  and can continue to skip the translation step from or into the
  filesystem's idmapping. And of course, if the low-level helpers detect
  that they are not dealing with an idmapped mount they can simply
  return the relevant id unchanged; no remapping needs to be performed
  at all.

  These checks guarantee that only the minimal amount of work is
  performed. As before, if idmapped mounts aren't used the low-level
  helpers are idempotent and no work is performed at all"

Link: 2ca4dcc490 ("fs/mount_setattr: tighten permission checks") [1]
Link: https://github.com/containers/podman/issues/10374 [2]
Link: Documentations/filesystems/idmappings.rst [3]
Link: a65e58e791 ("fs: document and rename fsid helpers") [4]

* tag 'fs.idmapped.v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
  fs: support mapped mounts of mapped filesystems
  fs: add i_user_ns() helper
  fs: port higher-level mapping helpers
  fs: remove unused low-level mapping helpers
  fs: use low-level mapping helpers
  docs: update mapping documentation
  fs: account for filesystem mappings
  fs: tweak fsuidgid_has_mapping()
  fs: move mapping helpers
  fs: add is_idmapped_mnt() helper
2022-01-11 14:26:55 -08:00
Darrick J. Wong
7e937bb3cb xfs: warn about inodes with project id of -1
Inodes aren't supposed to have a project id of -1U (aka 4294967295) but
the kernel hasn't always validated FSSETXATTR correctly.  Flag this as
something for the sysadmin to check out.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-01-06 10:43:30 -08:00
Darrick J. Wong
eae44cb341 xfs: hold quota inode ILOCK_EXCL until the end of dqalloc
Online fsck depends on callers holding ILOCK_EXCL from the time they
decide to update a block mapping until after they've updated the reverse
mapping records to guarantee the stability of both mapping records.
Unfortunately, the quota code drops ILOCK_EXCL at the first transaction
roll in the dquot allocation process, which breaks that assertion.  This
leads to sporadic failures in the online rmap repair code if the repair
code grabs the AGF after bmapi_write maps a new block into the quota
file's data fork but before it can finish the deferred rmap update.

Fix this by rewriting the function to hold the ILOCK until after the
transaction commit like all other bmap updates do, and get rid of the
dqread wrapper that does nothing but complicate the codebase.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-01-06 10:43:30 -08:00
Jiapeng Chong
f4901a182d xfs: Remove redundant assignment of mp
mp is being initialized to log->l_mp but this is never read
as record is overwritten later on. Remove the redundant
assignment.

Cleans up the following clang-analyzer warning:

fs/xfs/xfs_log_recover.c:3543:20: warning: Value stored to 'mp' during
its initialization is never read [clang-analyzer-deadcode.DeadStores].

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2022-01-06 10:43:30 -08:00
Dave Chinner
8dc9384b7d xfs: reduce kvmalloc overhead for CIL shadow buffers
Oh, let me count the ways that the kvmalloc API sucks dog eggs.

The problem is when we are logging lots of large objects, we hit
kvmalloc really damn hard with costly order allocations, and
behaviour utterly sucks:

     - 49.73% xlog_cil_commit
	 - 31.62% kvmalloc_node
	    - 29.96% __kmalloc_node
	       - 29.38% kmalloc_large_node
		  - 29.33% __alloc_pages
		     - 24.33% __alloc_pages_slowpath.constprop.0
			- 18.35% __alloc_pages_direct_compact
			   - 17.39% try_to_compact_pages
			      - compact_zone_order
				 - 15.26% compact_zone
				      5.29% __pageblock_pfn_to_page
				      3.71% PageHuge
				    - 1.44% isolate_migratepages_block
					 0.71% set_pfnblock_flags_mask
				   1.11% get_pfnblock_flags_mask
			   - 0.81% get_page_from_freelist
			      - 0.59% _raw_spin_lock_irqsave
				 - do_raw_spin_lock
				      __pv_queued_spin_lock_slowpath
			- 3.24% try_to_free_pages
			   - 3.14% shrink_node
			      - 2.94% shrink_slab.constprop.0
				 - 0.89% super_cache_count
				    - 0.66% xfs_fs_nr_cached_objects
				       - 0.65% xfs_reclaim_inodes_count
					    0.55% xfs_perag_get_tag
				   0.58% kfree_rcu_shrink_count
			- 2.09% get_page_from_freelist
			   - 1.03% _raw_spin_lock_irqsave
			      - do_raw_spin_lock
				   __pv_queued_spin_lock_slowpath
		     - 4.88% get_page_from_freelist
			- 3.66% _raw_spin_lock_irqsave
			   - do_raw_spin_lock
				__pv_queued_spin_lock_slowpath
	    - 1.63% __vmalloc_node
	       - __vmalloc_node_range
		  - 1.10% __alloc_pages_bulk
		     - 0.93% __alloc_pages
			- 0.92% get_page_from_freelist
			   - 0.89% rmqueue_bulk
			      - 0.69% _raw_spin_lock
				 - do_raw_spin_lock
				      __pv_queued_spin_lock_slowpath
	   13.73% memcpy_erms
	 - 2.22% kvfree

On this workload, that's almost a dozen CPUs all trying to compact
and reclaim memory inside kvmalloc_node at the same time. Yet it is
regularly falling back to vmalloc despite all that compaction, page
and shrinker reclaim that direct reclaim is doing. Copying all the
metadata is taking far less CPU time than allocating the storage!

Direct reclaim should be considered extremely harmful.

This is a high frequency, high throughput, CPU usage and latency
sensitive allocation. We've got memory there, and we're using
kvmalloc to allow memory allocation to avoid doing lots of work to
try to do contiguous allocations.

Except it still does *lots of costly work* that is unnecessary.

Worse: the only way to avoid the slowpath page allocation trying to
do compaction on costly allocations is to turn off direct reclaim
(i.e. remove __GFP_RECLAIM_DIRECT from the gfp flags).

Unfortunately, the stupid kvmalloc API then says "oh, this isn't a
GFP_KERNEL allocation context, so you only get kmalloc!". This
cuts off the vmalloc fallback, and this leads to almost instant OOM
problems which ends up in filesystems deadlocks, shutdowns and/or
kernel crashes.

I want some basic kvmalloc behaviour:

- kmalloc for a contiguous range with fail fast semantics - no
  compaction direct reclaim if the allocation enters the slow path.
- run normal vmalloc (i.e. GFP_KERNEL) if kmalloc fails

The really, really stupid part about this is these kvmalloc() calls
are run under memalloc_nofs task context, so all the allocations are
always reduced to GFP_NOFS regardless of the fact that kvmalloc
requires GFP_KERNEL to be passed in. IOWs, we're already telling
kvmalloc to behave differently to the gfp flags we pass in, but it
still won't allow vmalloc to be run with anything other than
GFP_KERNEL.

So, this patch open codes the kvmalloc() in the commit path to have
the above described behaviour. The result is we more than halve the
CPU time spend doing kvmalloc() in this path and transaction commits
with 64kB objects in them more than doubles. i.e. we get ~5x
reduction in CPU usage per costly-sized kvmalloc() invocation and
the profile looks like this:

  - 37.60% xlog_cil_commit
	16.01% memcpy_erms
      - 8.45% __kmalloc
	 - 8.04% kmalloc_order_trace
	    - 8.03% kmalloc_order
	       - 7.93% alloc_pages
		  - 7.90% __alloc_pages
		     - 4.05% __alloc_pages_slowpath.constprop.0
			- 2.18% get_page_from_freelist
			- 1.77% wake_all_kswapds
....
				    - __wake_up_common_lock
				       - 0.94% _raw_spin_lock_irqsave
		     - 3.72% get_page_from_freelist
			- 2.43% _raw_spin_lock_irqsave
      - 5.72% vmalloc
	 - 5.72% __vmalloc_node_range
	    - 4.81% __get_vm_area_node.constprop.0
	       - 3.26% alloc_vmap_area
		  - 2.52% _raw_spin_lock
	       - 1.46% _raw_spin_lock
	      0.56% __alloc_pages_bulk
      - 4.66% kvfree
	 - 3.25% vfree
	    - __vfree
	       - 3.23% __vunmap
		  - 1.95% remove_vm_area
		     - 1.06% free_vmap_area_noflush
			- 0.82% _raw_spin_lock
		     - 0.68% _raw_spin_lock
		  - 0.92% _raw_spin_lock
	 - 1.40% kfree
	    - 1.36% __free_pages
	       - 1.35% __free_pages_ok
		  - 1.02% _raw_spin_lock_irqsave

It's worth noting that over 50% of the CPU time spent allocating
these shadow buffers is now spent on spinlocks. So the shadow buffer
allocation overhead is greatly reduced by getting rid of direct
reclaim from kmalloc, and could probably be made even less costly if
vmalloc() didn't use global spinlocks to protect it's structures.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2022-01-06 10:43:30 -08:00
Greg Kroah-Hartman
219aac5d46 xfs: sysfs: use default_groups in kobj_type
There are currently 2 ways to create a set of sysfs files for a
kobj_type, through the default_attrs field, and the default_groups
field.  Move the xfs sysfs code to use default_groups field which has
been the preferred way since aa30f47cf6 ("kobject: Add support for
default attribute groups to kobj_type") so that we can soon get rid of
the obsolete default_attrs field.

Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: linux-xfs@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2022-01-06 10:43:30 -08:00
Darrick J. Wong
983d8e60f5 xfs: map unwritten blocks in XFS_IOC_{ALLOC,FREE}SP just like fallocate
The old ALLOCSP/FREESP ioctls in XFS can be used to preallocate space at
the end of files, just like fallocate and RESVSP.  Make the behavior
consistent with the other ioctls.

Reported-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
2021-12-22 14:19:18 -08:00
Darrick J. Wong
f8d92a66e8 xfs: prevent UAF in xfs_log_item_in_current_chkpt
While I was running with KASAN and lockdep enabled, I stumbled upon an
KASAN report about a UAF to a freed CIL checkpoint.  Looking at the
comment for xfs_log_item_in_current_chkpt, it seems pretty obvious to me
that the original patch to xfs_defer_finish_noroll should have done
something to lock the CIL to prevent it from switching the CIL contexts
while the predicate runs.

For upper level code that needs to know if a given log item is new
enough not to need relogging, add a new wrapper that takes the CIL
context lock long enough to sample the current CIL context.  This is
kind of racy in that the CIL can switch the contexts immediately after
sampling, but that's ok because the consequence is that the defer ops
code is a little slow to relog items.

 ==================================================================
 BUG: KASAN: use-after-free in xfs_log_item_in_current_chkpt+0x139/0x160 [xfs]
 Read of size 8 at addr ffff88804ea5f608 by task fsstress/527999

 CPU: 1 PID: 527999 Comm: fsstress Tainted: G      D      5.16.0-rc4-xfsx #rc4
 Call Trace:
  <TASK>
  dump_stack_lvl+0x45/0x59
  print_address_description.constprop.0+0x1f/0x140
  kasan_report.cold+0x83/0xdf
  xfs_log_item_in_current_chkpt+0x139/0x160
  xfs_defer_finish_noroll+0x3bb/0x1e30
  __xfs_trans_commit+0x6c8/0xcf0
  xfs_reflink_remap_extent+0x66f/0x10e0
  xfs_reflink_remap_blocks+0x2dd/0xa90
  xfs_file_remap_range+0x27b/0xc30
  vfs_dedupe_file_range_one+0x368/0x420
  vfs_dedupe_file_range+0x37c/0x5d0
  do_vfs_ioctl+0x308/0x1260
  __x64_sys_ioctl+0xa1/0x170
  do_syscall_64+0x35/0x80
  entry_SYSCALL_64_after_hwframe+0x44/0xae
 RIP: 0033:0x7f2c71a2950b
 Code: 0f 1e fa 48 8b 05 85 39 0d 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff
ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa b8 10 00 00 00 0f 05 <48> 3d 01
f0 ff ff 73 01 c3 48 8b 0d 55 39 0d 00 f7 d8 64 89 01 48
 RSP: 002b:00007ffe8c0e03c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
 RAX: ffffffffffffffda RBX: 00005600862a8740 RCX: 00007f2c71a2950b
 RDX: 00005600862a7be0 RSI: 00000000c0189436 RDI: 0000000000000004
 RBP: 000000000000000b R08: 0000000000000027 R09: 0000000000000003
 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000005a
 R13: 00005600862804a8 R14: 0000000000016000 R15: 00005600862a8a20
  </TASK>

 Allocated by task 464064:
  kasan_save_stack+0x1e/0x50
  __kasan_kmalloc+0x81/0xa0
  kmem_alloc+0xcd/0x2c0 [xfs]
  xlog_cil_ctx_alloc+0x17/0x1e0 [xfs]
  xlog_cil_push_work+0x141/0x13d0 [xfs]
  process_one_work+0x7f6/0x1380
  worker_thread+0x59d/0x1040
  kthread+0x3b0/0x490
  ret_from_fork+0x1f/0x30

 Freed by task 51:
  kasan_save_stack+0x1e/0x50
  kasan_set_track+0x21/0x30
  kasan_set_free_info+0x20/0x30
  __kasan_slab_free+0xed/0x130
  slab_free_freelist_hook+0x7f/0x160
  kfree+0xde/0x340
  xlog_cil_committed+0xbfd/0xfe0 [xfs]
  xlog_cil_process_committed+0x103/0x1c0 [xfs]
  xlog_state_do_callback+0x45d/0xbd0 [xfs]
  xlog_ioend_work+0x116/0x1c0 [xfs]
  process_one_work+0x7f6/0x1380
  worker_thread+0x59d/0x1040
  kthread+0x3b0/0x490
  ret_from_fork+0x1f/0x30

 Last potentially related work creation:
  kasan_save_stack+0x1e/0x50
  __kasan_record_aux_stack+0xb7/0xc0
  insert_work+0x48/0x2e0
  __queue_work+0x4e7/0xda0
  queue_work_on+0x69/0x80
  xlog_cil_push_now.isra.0+0x16b/0x210 [xfs]
  xlog_cil_force_seq+0x1b7/0x850 [xfs]
  xfs_log_force_seq+0x1c7/0x670 [xfs]
  xfs_file_fsync+0x7c1/0xa60 [xfs]
  __x64_sys_fsync+0x52/0x80
  do_syscall_64+0x35/0x80
  entry_SYSCALL_64_after_hwframe+0x44/0xae

 The buggy address belongs to the object at ffff88804ea5f600
  which belongs to the cache kmalloc-256 of size 256
 The buggy address is located 8 bytes inside of
  256-byte region [ffff88804ea5f600, ffff88804ea5f700)
 The buggy address belongs to the page:
 page:ffffea00013a9780 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88804ea5ea00 pfn:0x4ea5e
 head:ffffea00013a9780 order:1 compound_mapcount:0
 flags: 0x4fff80000010200(slab|head|node=1|zone=1|lastcpupid=0xfff)
 raw: 04fff80000010200 ffffea0001245908 ffffea00011bd388 ffff888004c42b40
 raw: ffff88804ea5ea00 0000000000100009 00000001ffffffff 0000000000000000
 page dumped because: kasan: bad access detected

 Memory state around the buggy address:
  ffff88804ea5f500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
  ffff88804ea5f580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 >ffff88804ea5f600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                       ^
  ffff88804ea5f680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
  ffff88804ea5f700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ==================================================================

Fixes: 4e919af782 ("xfs: periodically relog deferred intent items")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2021-12-22 14:17:55 -08:00
Dan Carpenter
6ed6356b07 xfs: prevent a WARN_ONCE() in xfs_ioc_attr_list()
The "bufsize" comes from the root user.  If "bufsize" is negative then,
because of type promotion, neither of the validation checks at the start
of the function are able to catch it:

	if (bufsize < sizeof(struct xfs_attrlist) ||
	    bufsize > XFS_XATTR_LIST_MAX)
		return -EINVAL;

This means "bufsize" will trigger (WARN_ON_ONCE(size > INT_MAX)) in
kvmalloc_node().  Fix this by changing the type from int to size_t.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-12-21 09:49:41 -08:00
Yang Xu
132c460e49 xfs: Fix comments mentioning xfs_ialloc
Since kernel commit 1abcf26101 ("xfs: move on-disk inode allocation out of xfs_ialloc()"),
xfs_ialloc has been renamed to xfs_init_new_inode. So update this in comments.

Signed-off-by: Yang Xu <xuyang2018.jy@fujitsu.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-12-21 09:49:41 -08:00
Dave Chinner
09654ed8a1 xfs: check sb_meta_uuid for dabuf buffer recovery
Got a report that a repeated crash test of a container host would
eventually fail with a log recovery error preventing the system from
mounting the root filesystem. It manifested as a directory leaf node
corruption on writeback like so:

 XFS (loop0): Mounting V5 Filesystem
 XFS (loop0): Starting recovery (logdev: internal)
 XFS (loop0): Metadata corruption detected at xfs_dir3_leaf_check_int+0x99/0xf0, xfs_dir3_leaf1 block 0x12faa158
 XFS (loop0): Unmount and run xfs_repair
 XFS (loop0): First 128 bytes of corrupted metadata buffer:
 00000000: 00 00 00 00 00 00 00 00 3d f1 00 00 e1 9e d5 8b  ........=.......
 00000010: 00 00 00 00 12 fa a1 58 00 00 00 29 00 00 1b cc  .......X...)....
 00000020: 91 06 78 ff f7 7e 4a 7d 8d 53 86 f2 ac 47 a8 23  ..x..~J}.S...G.#
 00000030: 00 00 00 00 17 e0 00 80 00 43 00 00 00 00 00 00  .........C......
 00000040: 00 00 00 2e 00 00 00 08 00 00 17 2e 00 00 00 0a  ................
 00000050: 02 35 79 83 00 00 00 30 04 d3 b4 80 00 00 01 50  .5y....0.......P
 00000060: 08 40 95 7f 00 00 02 98 08 41 fe b7 00 00 02 d4  .@.......A......
 00000070: 0d 62 ef a7 00 00 01 f2 14 50 21 41 00 00 00 0c  .b.......P!A....
 XFS (loop0): Corruption of in-memory data (0x8) detected at xfs_do_force_shutdown+0x1a/0x20 (fs/xfs/xfs_buf.c:1514).  Shutting down.
 XFS (loop0): Please unmount the filesystem and rectify the problem(s)
 XFS (loop0): log mount/recovery failed: error -117
 XFS (loop0): log mount failed

Tracing indicated that we were recovering changes from a transaction
at LSN 0x29/0x1c16 into a buffer that had an LSN of 0x29/0x1d57.
That is, log recovery was overwriting a buffer with newer changes on
disk than was in the transaction. Tracing indicated that we were
hitting the "recovery immediately" case in
xfs_buf_log_recovery_lsn(), and hence it was ignoring the LSN in the
buffer.

The code was extracting the LSN correctly, then ignoring it because
the UUID in the buffer did not match the superblock UUID. The
problem arises because the UUID check uses the wrong UUID - it
should be checking the sb_meta_uuid, not sb_uuid. This filesystem
has sb_uuid != sb_meta_uuid (which is fine), and the buffer has the
correct matching sb_meta_uuid in it, it's just the code checked it
against the wrong superblock uuid.

The is no corruption in the filesystem, and failing to recover the
buffer due to a write verifier failure means the recovery bug did
not propagate the corruption to disk. Hence there is no corruption
before or after this bug has manifested, the impact is limited
simply to an unmountable filesystem....

This was missed back in 2015 during an audit of incorrect sb_uuid
usage that resulted in commit fcfbe2c4ef ("xfs: log recovery needs
to validate against sb_meta_uuid") that fixed the magic32 buffers to
validate against sb_meta_uuid instead of sb_uuid. It missed the
magicda buffers....

Fixes: ce748eaa65 ("xfs: create new metadata UUID field and incompat flag")
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-12-21 09:49:41 -08:00
Darrick J. Wong
e5d1802c70 xfs: fix a bug in the online fsck directory leaf1 bestcount check
When xfs_scrub encounters a directory with a leaf1 block, it tries to
validate that the leaf1 block's bestcount (aka the best free count of
each directory data block) is the correct size.  Previously, this author
believed that comparing bestcount to the directory isize (since
directory data blocks are under isize, and leaf/bestfree blocks are
above it) was sufficient.

Unfortunately during testing of online repair, it was discovered that it
is possible to create a directory with a hole between the last directory
block and isize.  The directory code seems to handle this situation just
fine and xfs_repair doesn't complain, which effectively makes this quirk
part of the disk format.

Fix the check to work properly.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2021-12-21 09:49:41 -08:00
Darrick J. Wong
7993f1a431 xfs: only run COW extent recovery when there are no live extents
As part of multiple customer escalations due to file data corruption
after copy on write operations, I wrote some fstests that use fsstress
to hammer on COW to shake things loose.  Regrettably, I caught some
filesystem shutdowns due to incorrect rmap operations with the following
loop:

mount <filesystem>				# (0)
fsstress <run only readonly ops> &		# (1)
while true; do
	fsstress <run all ops>
	mount -o remount,ro			# (2)
	fsstress <run only readonly ops>
	mount -o remount,rw			# (3)
done

When (2) happens, notice that (1) is still running.  xfs_remount_ro will
call xfs_blockgc_stop to walk the inode cache to free all the COW
extents, but the blockgc mechanism races with (1)'s reader threads to
take IOLOCKs and loses, which means that it doesn't clean them all out.
Call such a file (A).

When (3) happens, xfs_remount_rw calls xfs_reflink_recover_cow, which
walks the ondisk refcount btree and frees any COW extent that it finds.
This function does not check the inode cache, which means that incore
COW forks of inode (A) is now inconsistent with the ondisk metadata.  If
one of those former COW extents are allocated and mapped into another
file (B) and someone triggers a COW to the stale reservation in (A), A's
dirty data will be written into (B) and once that's done, those blocks
will be transferred to (A)'s data fork without bumping the refcount.

The results are catastrophic -- file (B) and the refcount btree are now
corrupt.  In the first patch, we fixed the race condition in (2) so that
(A) will always flush the COW fork.  In this second patch, we move the
_recover_cow call to the initial mount call in (0) for safety.

As mentioned previously, xfs_reflink_recover_cow walks the refcount
btree looking for COW staging extents, and frees them.  This was
intended to be run at mount time (when we know there are no live inodes)
to clean up any leftover staging events that may have been left behind
during an unclean shutdown.  As a time "optimization" for readonly
mounts, we deferred this to the ro->rw transition, not realizing that
any failure to clean all COW forks during a rw->ro transition would
result in catastrophic corruption.

Therefore, remove this optimization and only run the recovery routine
when we're guaranteed not to have any COW staging extents anywhere,
which means we always run this at mount time.  While we're at it, move
the callsite to xfs_log_mount_finish because any refcount btree
expansion (however unlikely given that we're removing records from the
right side of the index) must be fed by a per-AG reservation, which
doesn't exist in its current location.

Fixes: 174edb0e46 ("xfs: store in-progress CoW allocations in the refcount btree")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2021-12-21 09:49:41 -08:00
Darrick J. Wong
7b7820b83f xfs: don't expose internal symlink metadata buffers to the vfs
Ian Kent reported that for inline symlinks, it's possible for
vfs_readlink to hang on to the target buffer returned by
_vn_get_link_inline long after it's been freed by xfs inode reclaim.
This is a layering violation -- we should never expose XFS internals to
the VFS.

When the symlink has a remote target, we allocate a separate buffer,
copy the internal information, and let the VFS manage the new buffer's
lifetime.  Let's adapt the inline code paths to do this too.  It's
less efficient, but fixes the layering violation and avoids the need to
adapt the if_data lifetime to rcu rules.  Clearly I don't care about
readlink benchmarks.

As a side note, this fixes the minor locking violation where we can
access the inode data fork without taking any locks; proper locking (and
eliminating the possibility of having to switch inode_operations on a
live inode) is essential to online repair coordinating repairs
correctly.

Reported-by: Ian Kent <raven@themaw.net>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2021-12-21 09:49:41 -08:00
Darrick J. Wong
59d7fab2df xfs: fix quotaoff mutex usage now that we don't support disabling it
Prior to commit 40b52225e5 ("xfs: remove support for disabling quota
accounting on a mounted file system"), we used the quotaoff mutex to
protect dquot operations against quotaoff trying to pull down dquots as
part of disabling quota.

Now that we only support turning off quota enforcement, the quotaoff
mutex only protects changes in m_qflags/sb_qflags.  We don't need it to
protect dquots, which means we can remove it from setqlimits and the
dquot scrub code.  While we're at it, fix the function that forces
quotacheck, since it should have been taking the quotaoff mutex.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2021-12-21 09:49:41 -08:00
Darrick J. Wong
47a6df7cd3 xfs: shut down filesystem if we xfs_trans_cancel with deferred work items
While debugging some very strange rmap corruption reports in connection
with the online directory repair code.  I root-caused the error to the
following incorrect sequence:

<start repair transaction>
<expand directory, causing a deferred rmap to be queued>
<roll transaction>
<cancel transaction>

Obviously, we should have committed the transaction instead of
cancelling it.  Thinking more broadly, however, xfs_trans_cancel should
have warned us that we were throwing away work item that we already
committed to performing.  This is not correct, and we need to shut down
the filesystem.

Change xfs_trans_cancel to complain in the loudest manner if we're
cancelling any transaction with deferred work items attached.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2021-12-21 09:49:41 -08:00
Matthew Wilcox (Oracle)
6795801366 xfs: Support large folios
Now that iomap has been converted, XFS is large folio safe.
Indicate to the VFS that it can now create large folios for XFS.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2021-12-18 00:06:08 -05:00
Matthew Wilcox (Oracle)
6e478521df iomap,xfs: Convert ->discard_page to ->discard_folio
XFS has the only implementation of ->discard_page today, so convert it
to use folios in the same patch as converting the API.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2021-12-18 00:06:07 -05:00
Darrick J. Wong
089558bc7b xfs: remove all COW fork extents when remounting readonly
As part of multiple customer escalations due to file data corruption
after copy on write operations, I wrote some fstests that use fsstress
to hammer on COW to shake things loose.  Regrettably, I caught some
filesystem shutdowns due to incorrect rmap operations with the following
loop:

mount <filesystem>				# (0)
fsstress <run only readonly ops> &		# (1)
while true; do
	fsstress <run all ops>
	mount -o remount,ro			# (2)
	fsstress <run only readonly ops>
	mount -o remount,rw			# (3)
done

When (2) happens, notice that (1) is still running.  xfs_remount_ro will
call xfs_blockgc_stop to walk the inode cache to free all the COW
extents, but the blockgc mechanism races with (1)'s reader threads to
take IOLOCKs and loses, which means that it doesn't clean them all out.
Call such a file (A).

When (3) happens, xfs_remount_rw calls xfs_reflink_recover_cow, which
walks the ondisk refcount btree and frees any COW extent that it finds.
This function does not check the inode cache, which means that incore
COW forks of inode (A) is now inconsistent with the ondisk metadata.  If
one of those former COW extents are allocated and mapped into another
file (B) and someone triggers a COW to the stale reservation in (A), A's
dirty data will be written into (B) and once that's done, those blocks
will be transferred to (A)'s data fork without bumping the refcount.

The results are catastrophic -- file (B) and the refcount btree are now
corrupt.  Solve this race by forcing the xfs_blockgc_free_space to run
synchronously, which causes xfs_icwalk to return to inodes that were
skipped because the blockgc code couldn't take the IOLOCK.  This is safe
to do here because the VFS has already prohibited new writer threads.

Fixes: 10ddf64e42 ("xfs: remove leftover CoW reservations when remounting ro")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
2021-12-07 10:17:29 -08:00
Christian Brauner
209188ce75
fs: port higher-level mapping helpers
Enable the mapped_fs{g,u}id() helpers to support filesystems mounted
with an idmapping. Apart from core mapping helpers that use
mapped_fs{g,u}id() to initialize struct inode's i_{g,u}id fields xfs is
the only place that uses these low-level helpers directly.

The patch only extends the helpers to be able to take the filesystem
idmapping into account. Since we don't actually yet pass the
filesystem's idmapping in no functional changes happen. This will happen
in a final patch.

Link: https://lore.kernel.org/r/20211123114227.3124056-9-brauner@kernel.org (v1)
Link: https://lore.kernel.org/r/20211130121032.3753852-9-brauner@kernel.org (v2)
Link: https://lore.kernel.org/r/20211203111707.3901969-9-brauner@kernel.org
Cc: Seth Forshee <sforshee@digitalocean.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
CC: linux-fsdevel@vger.kernel.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Seth Forshee <sforshee@digitalocean.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2021-12-05 10:28:57 +01:00
Christoph Hellwig
de20511477 fsdax: shift partition offset handling into the file systems
Remove the last user of ->bdev in dax.c by requiring the file system to
pass in an address that already includes the DAX offset.  As part of the
only set ->bdev or ->daxdev when actually required in the ->iomap_begin
methods.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> [erofs]
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-27-hch@lst.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2021-12-04 08:58:54 -08:00