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Author SHA1 Message Date
Darrick J. Wong
7e1b84b24d xfs: hook live rmap operations during a repair operation
Hook the regular rmap code when an rmapbt repair operation is running so
that we can unlock the AGF buffer to scan the filesystem and keep the
in-memory btree up to date during the scan.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22 12:43:40 -08:00
Darrick J. Wong
32080a9b9b xfs: repair the rmapbt
Rebuild the reverse mapping btree from all primary metadata.  This first
patch establishes the bare mechanics of finding records and putting
together a new ondisk tree; more complex pieces are needed to make it
work properly.

Link: Documentation/filesystems/xfs-online-fsck-design.rst
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22 12:43:38 -08:00
Darrick J. Wong
a095686a23 xfs: support in-memory btrees
Adapt the generic btree cursor code to be able to create a btree whose
buffers come from a (presumably in-memory) buftarg with a header block
that's specific to in-memory btrees.  We'll connect this to other parts
of online scrub in the next patches.

Note that in-memory btrees always have a block size matching the system
memory page size for efficiency reasons.  There are also a few things we
need to do to finalize a btree update; that's covered in the next patch.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22 12:43:35 -08:00
Darrick J. Wong
4ed080cd7c xfs: repair summary counters
Use the same summary counter calculation infrastructure to generate new
values for the in-core summary counters.   The difference between the
scrubber and the repairer is that the repairer will freeze the fs during
setup, which means that the values should match exactly.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22 12:33:05 -08:00
Darrick J. Wong
a1f3e0cca4 xfs: update health status if we get a clean bill of health
If scrub finds that everything is ok with the filesystem, we need a way
to tell the health tracking that it can let go of indirect health flags,
since indirect flags only mean that at some point in the past we lost
some context.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22 12:33:04 -08:00
Darrick J. Wong
6b631c60c9 xfs: teach repair to fix file nlinks
Fix the file link counts since we just computed the correct ones.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22 12:31:00 -08:00
Darrick J. Wong
86a1746eea xfs: track directory entry updates during live nlinks fsck
Create the necessary hooks in the directory operations
(create/link/unlink/rename) code so that our live nlink scrub code can
stay up to date with link count updates in the rest of the filesystem.
This will be the means to keep our shadow link count information up to
date while the scan runs in real time.

In online fsck part 2, we'll use these same hooks to handle repairs
to directories and parent pointer information.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22 12:30:59 -08:00
Darrick J. Wong
f1184081ac xfs: teach scrub to check file nlinks
Create the necessary scrub code to walk the filesystem's directory tree
so that we can compute file link counts.  Similar to quotacheck, we
create an incore shadow array of link count information and then we walk
the filesystem a second time to compare the link counts.  We need live
updates to keep the information up to date during the lengthy scan, so
this scrubber remains disabled until the next patch.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22 12:30:58 -08:00
Darrick J. Wong
96ed2ae4a9 xfs: repair dquots based on live quotacheck results
Use the shadow quota counters that live quotacheck creates to reset the
incore dquot counters.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22 12:30:57 -08:00
Darrick J. Wong
200491875c xfs: track quota updates during live quotacheck
Create a shadow dqtrx system in the quotacheck code that hooks the
regular dquot counter update code.  This will be the means to keep our
copy of the dquot counters up to date while the scan runs in real time.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22 12:30:55 -08:00
Darrick J. Wong
48dd9117a3 xfs: implement live quotacheck inode scan
Create a new trio of scrub functions to check quota counters.  While the
dquots themselves are filesystem metadata and should be checked early,
the dquot counter values are computed from other metadata and are
therefore summary counters.  We don't plug these into the scrub dispatch
just yet, because we still need to be able to watch quota updates while
doing our scan.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22 12:30:54 -08:00
Darrick J. Wong
a5b9155540 xfs: repair quotas
Fix anything that causes the quota verifiers to fail.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2023-12-15 10:03:45 -08:00
Darrick J. Wong
ffd37b22bd xfs: online repair of realtime bitmaps
Fix all the file metadata surrounding the realtime bitmap file, which
includes the rt geometry, file size, forks, and space mappings.  The
bitmap contents themselves cannot be fixed without rt rmap, so that will
come later.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2023-12-15 10:03:43 -08:00
Darrick J. Wong
20cc0d398e xfs: always check the rtbitmap and rtsummary files
XFS filesystems always have a realtime bitmap and summary file, even if
there has never been a realtime volume attached.  Always check them.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2023-12-15 10:03:42 -08:00
Darrick J. Wong
dbbdbd0086 xfs: repair problems in CoW forks
Try to repair errors that we see in file CoW forks so that we don't do
stupid things like remap garbage into a file.  There's not a lot we can
do with the COW fork -- the ondisk metadata record only that the COW
staging extents are owned by the refcount btree, which effectively means
that we can't reconstruct this incore structure from scratch.

Actually, this is even worse -- we can't touch written extents, because
those map space that are actively under writeback, and there's not much
to do with delalloc reservations.  Hence we can only detect crosslinked
unwritten extents and fix them by punching out the problematic parts and
replacing them with delalloc extents.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2023-12-15 10:03:40 -08:00
Darrick J. Wong
48a72f6086 xfs: refactor repair forcing tests into a repair.c helper
There are a couple of conditions that userspace can set to force repairs
of metadata.  These really belong in the repair code and not open-coded
into the check code, so refactor them into a helper.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2023-12-15 10:03:39 -08:00
Darrick J. Wong
8f71bede8e xfs: repair inode fork block mapping data structures
Use the reverse-mapping btree information to rebuild an inode block map.
Update the btree bulk loading code as necessary to support inode rooted
btrees and fix some bitrot problems.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2023-12-15 10:03:39 -08:00
Darrick J. Wong
2d295fe657 xfs: repair inode records
If an inode is so badly damaged that it cannot be loaded into the cache,
fix the ondisk metadata and try again.  If there /is/ a cached inode,
fix any problems and apply any optimizations that can be solved incore.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2023-12-15 10:03:36 -08:00
Darrick J. Wong
9099cd3800 xfs: repair refcount btrees
Reconstruct the refcount data from the rmap btree.

Link: https://docs.kernel.org/filesystems/xfs-online-fsck-design.html#case-study-rebuilding-the-space-reference-counts
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2023-12-15 10:03:33 -08:00
Darrick J. Wong
dbfbf3bdf6 xfs: repair inode btrees
Use the rmapbt to find inode chunks, query the chunks to compute hole
and free masks, and with that information rebuild the inobt and finobt.
Refer to the case study in
Documentation/filesystems/xfs-online-fsck-design.rst for more details.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2023-12-15 10:03:32 -08:00
Darrick J. Wong
4bdfd7d157 xfs: repair free space btrees
Rebuild the free space btrees from the gaps in the rmap btree.  Refer to
the case study in Documentation/filesystems/xfs-online-fsck-design.rst
for more details.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2023-12-15 10:03:32 -08:00
Darrick J. Wong
8bd0bf570b xfs: remove trivial bnobt/inobt scrub helpers
Christoph Hellwig complained about awkward code in the next two repair
patches such as:

	sc->sm->sm_type = XFS_SCRUB_TYPE_BNOBT;
	error = xchk_bnobt(sc);

This is a little silly, so let's export the xchk_{,i}allocbt functions
to the dispatch table in scrub.c directly and get rid of the helpers.
Originally I had planned each btree gets its own separate entry point,
but since repair doesn't work that way, it no longer makes sense to
complicate the call chain that way.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2023-12-15 10:03:31 -08:00
Darrick J. Wong
e031928200 xfs: only call xchk_stats_merge after validating scrub inputs
Harshit Mogalapalli slogged through several reports from our internal
syzbot instance and observed that they all had a common stack trace:

BUG: KASAN: user-memory-access in instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
BUG: KASAN: user-memory-access in atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1294 [inline]
BUG: KASAN: user-memory-access in queued_spin_lock include/asm-generic/qspinlock.h:111 [inline]
BUG: KASAN: user-memory-access in do_raw_spin_lock include/linux/spinlock.h:187 [inline]
BUG: KASAN: user-memory-access in __raw_spin_lock include/linux/spinlock_api_smp.h:134 [inline]
BUG: KASAN: user-memory-access in _raw_spin_lock+0x76/0xe0 kernel/locking/spinlock.c:154
Write of size 4 at addr 0000001dd87ee280 by task syz-executor365/1543

CPU: 2 PID: 1543 Comm: syz-executor365 Not tainted 6.5.0-syzk #1
Hardware name: Red Hat KVM, BIOS 1.13.0-2.module+el8.3.0+7860+a7792d29 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x83/0xb0 lib/dump_stack.c:106
 print_report+0x3f8/0x620 mm/kasan/report.c:478
 kasan_report+0xb0/0xe0 mm/kasan/report.c:588
 check_region_inline mm/kasan/generic.c:181 [inline]
 kasan_check_range+0x139/0x1e0 mm/kasan/generic.c:187
 instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
 atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1294 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:111 [inline]
 do_raw_spin_lock include/linux/spinlock.h:187 [inline]
 __raw_spin_lock include/linux/spinlock_api_smp.h:134 [inline]
 _raw_spin_lock+0x76/0xe0 kernel/locking/spinlock.c:154
 spin_lock include/linux/spinlock.h:351 [inline]
 xchk_stats_merge_one.isra.1+0x39/0x650 fs/xfs/scrub/stats.c:191
 xchk_stats_merge+0x5f/0xe0 fs/xfs/scrub/stats.c:225
 xfs_scrub_metadata+0x252/0x14e0 fs/xfs/scrub/scrub.c:599
 xfs_ioc_scrub_metadata+0xc8/0x160 fs/xfs/xfs_ioctl.c:1646
 xfs_file_ioctl+0x3fd/0x1870 fs/xfs/xfs_ioctl.c:1955
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:871 [inline]
 __se_sys_ioctl fs/ioctl.c:857 [inline]
 __x64_sys_ioctl+0x199/0x220 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3e/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x6e/0xd8
RIP: 0033:0x7ff155af753d
Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 1b 79 2c 00 f7 d8 64 89 01 48
RSP: 002b:00007ffc006e2568 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ff155af753d
RDX: 00000000200000c0 RSI: 00000000c040583c RDI: 0000000000000003
RBP: 00000000ffffffff R08: 00000000004010c0 R09: 00000000004010c0
R10: 00000000004010c0 R11: 0000000000000246 R12: 0000000000400cb0
R13: 00007ffc006e2670 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

The root cause here is that xchk_stats_merge_one walks off the end of
the xchk_scrub_stats.cs_stats array because it has been fed a garbage
value in sm->sm_type.  That occurs because I put the xchk_stats_merge
in the wrong place -- it should have been after the last xchk_teardown
call on our way out of xfs_scrub_metadata because we only call the
teardown function if we called the setup function, and we don't call the
setup functions if the inputs are obviously garbage.

Thanks to Harshit for triaging the bug reports and bringing this to my
attention.

Fixes: d7a74cad8f ("xfs: track usage statistics of online fsck")
Reported-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-09-12 10:31:08 -07:00
Linus Torvalds
53ea7f624f New code for 6.6:
* Chandan Babu will be taking over as the XFS release manager.  He has
    reviewed all the patches that are in this branch, though I'm signing
    the branch one last time since I'm still technically maintainer. :P
  * Create a maintainer entry profile for XFS in which we lay out the
    various roles that I have played for many years.  Aside from release
    manager, the remaining roles are as yet unfilled.
  * Start merging online repair -- we now have in-memory pageable memory
    for staging btrees, a bunch of pending fixes, and we've started the
    process of refactoring the scrub support code to support more of
    repair.  In particular, reaping of old blocks from damaged structures.
  * Scrub the realtime summary file.
  * Fix a bug where scrub's quota iteration only ever returned the root
    dquot.  Oooops.
  * Fix some typos.
 
 Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Merge tag 'xfs-6.6-merge-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull xfs updates from Chandan Babu:

 - Chandan Babu will be taking over as the XFS release manager. He has
   reviewed all the patches that are in this branch, though I'm signing
   the branch one last time since I'm still technically maintainer. :P

 - Create a maintainer entry profile for XFS in which we lay out the
   various roles that I have played for many years.  Aside from release
   manager, the remaining roles are as yet unfilled.

 - Start merging online repair -- we now have in-memory pageable memory
   for staging btrees, a bunch of pending fixes, and we've started the
   process of refactoring the scrub support code to support more of
   repair.  In particular, reaping of old blocks from damaged structures.

 - Scrub the realtime summary file.

 - Fix a bug where scrub's quota iteration only ever returned the root
   dquot.  Oooops.

 - Fix some typos.

[ Pull request from Chandan Babu, but signed tag and description from
  Darrick Wong, thus the first person singular above is Darrick, not
  Chandan ]

* tag 'xfs-6.6-merge-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (37 commits)
  fs/xfs: Fix typos in comments
  xfs: fix dqiterate thinko
  xfs: don't check reflink iflag state when checking cow fork
  xfs: simplify returns in xchk_bmap
  xfs: rewrite xchk_inode_is_allocated to work properly
  xfs: hide xfs_inode_is_allocated in scrub common code
  xfs: fix agf_fllast when repairing an empty AGFL
  xfs: allow userspace to rebuild metadata structures
  xfs: clear pagf_agflreset when repairing the AGFL
  xfs: allow the user to cancel repairs before we start writing
  xfs: don't complain about unfixed metadata when repairs were injected
  xfs: implement online scrubbing of rtsummary info
  xfs: always rescan allegedly healthy per-ag metadata after repair
  xfs: move the realtime summary file scrubber to a separate source file
  xfs: wrap ilock/iunlock operations on sc->ip
  xfs: get our own reference to inodes that we want to scrub
  xfs: track usage statistics of online fsck
  xfs: improve xfarray quicksort pivot
  xfs: create scaffolding for creating debugfs entries
  xfs: cache pages used for xfarray quicksort convergence
  ...
2023-08-30 12:34:12 -07:00
Darrick J. Wong
5c83df2e54 xfs: allow userspace to rebuild metadata structures
Add a new (superuser-only) flag to the online metadata repair ioctl to
force it to rebuild structures, even if they're not broken.  We will use
this to move metadata structures out of the way during a free space
defragmentation operation.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-08-10 07:48:11 -07:00
Darrick J. Wong
8336a64eb7 xfs: don't complain about unfixed metadata when repairs were injected
While debugging other parts of online repair, I noticed that if someone
injects FORCE_SCRUB_REPAIR, starts an IFLAG_REPAIR scrub on a piece of
metadata, and the metadata repair fails, we'll log a message about
uncorrected errors in the filesystem.

This isn't strictly true if the scrub function didn't set OFLAG_CORRUPT
and we're only doing the repair because the error injection knob is set.
Repair functions are allowed to abort the entire operation at any point
before committing new metadata, in which case the piece of metadata is
in the same state as it was before.  Therefore, the log message should
be gated on the results of the scrub.  Refactor the predicate and
rearrange the code flow to make this happen.

Note: If the repair function errors out after it commits the new
metadata, the transaction cancellation will shut down the filesystem,
which is an obvious sign of corrupt metadata.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-08-10 07:48:10 -07:00
Darrick J. Wong
526aab5f57 xfs: implement online scrubbing of rtsummary info
Finish the realtime summary scrubber by adding the functions we need to
compute a fresh copy of the rtsummary info and comparing it to the copy
on disk.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-08-10 07:48:09 -07:00
Darrick J. Wong
294012fb07 xfs: wrap ilock/iunlock operations on sc->ip
Scrub tracks the resources that it's holding onto in the xfs_scrub
structure.  This includes the inode being checked (if applicable) and
the inode lock state of that inode.  Replace the open-coded structure
manipulation with a trivial helper to eliminate sources of error.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-08-10 07:48:08 -07:00
Darrick J. Wong
1730853950 xfs: get our own reference to inodes that we want to scrub
When we want to scrub a file, get our own reference to the inode
unconditionally.  This will make disposal rules simpler in the long run.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-08-10 07:48:08 -07:00
Darrick J. Wong
d7a74cad8f xfs: track usage statistics of online fsck
Track the usage, outcomes, and run times of the online fsck code, and
report these values via debugfs.  The columns in the file are:

 * scrubber name

 * number of scrub invocations
 * clean objects found
 * corruptions found
 * optimizations found
 * cross referencing failures
 * inconsistencies found during cross referencing
 * incomplete scrubs
 * warnings
 * number of time scrub had to retry
 * cumulative amount of time spent scrubbing (microseconds)

 * number of repair inovcations
 * successfully repaired objects
 * cumuluative amount of time spent repairing (microseconds)

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-08-10 07:48:07 -07:00
Darrick J. Wong
ce85a1e046 xfs: stabilize fs summary counters for online fsck
If the fscounters scrubber notices incorrect summary counters, it's
entirely possible that scrub is simply racing with other threads that
are updating the incore counters.  There isn't a good way to stabilize
percpu counters or set ourselves up to observe live updates with hooks
like we do for the quotacheck or nlinks scanners, so we instead choose
to freeze the filesystem long enough to walk the incore per-AG
structures.

Past me thought that it was going to be commonplace to have to freeze
the filesystem to perform some kind of repair and set up a whole
separate infrastructure to freeze the filesystem in such a way that
userspace could not unfreeze while we were running.  This involved
adding a mutex and freeze_super/thaw_super functions and dealing with
the fact that the VFS freeze/thaw functions can free the VFS superblock
references on return.

This was all very overwrought, since fscounters turned out to be the
only user of scrub freezes, and it doesn't require the log to quiesce,
only the incore superblock counters.  We prevent other threads from
changing the freeze level by calling freeze_super_excl with a custom
freeze cookie to keep everyone else out of the filesystem.

The end result is that fscounters should be much more efficient.  When
we're checking a busy system and we can't stabilize the counters, the
custom freeze will do less work, which should result in less downtime.
Repair should be similarly speedy, but that's in a later patch.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-08-04 08:20:57 -07:00
Darrick J. Wong
2d5f38a319 xfs: disable reaping in fscounters scrub
The fscounters scrub code doesn't work properly because it cannot
quiesce updates to the percpu counters in the filesystem, hence it
returns false corruption reports.  This has been fixed properly in
one of the online repair patchsets that are under review by replacing
the xchk_disable_reaping calls with an exclusive filesystem freeze.
Disabling background gc isn't sufficient to fix the problem.

In other words, scrub doesn't need to call xfs_inodegc_stop, which is
just as well since it wasn't correct to allow scrub to call
xfs_inodegc_start when something else could be calling xfs_inodegc_stop
(e.g. trying to freeze the filesystem).

Neuter the scrubber for now, and remove the xchk_*_reaping functions.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2023-05-02 09:16:14 +10:00
Darrick J. Wong
91781ff549 xfs: split freemap from xchk_xattr_buf.buf
Move the free space bitmap from somewhere in xchk_xattr_buf.buf[] to an
explicit pointer.  This is the start of removing the complex overloaded
memory buffer that is the source of weird memory misuse bugs.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-11 19:00:30 -07:00
Darrick J. Wong
a03297a0ca xfs: manage inode DONTCACHE status at irele time
Right now, there are statements scattered all over the online fsck
codebase about how we can't use XFS_IGET_DONTCACHE because of concerns
about scrub's unusual practice of releasing inodes with transactions
held.

However, iget is the wrong place to handle this -- the DONTCACHE state
doesn't matter at all until we try to *release* the inode, and here we
get things wrong in multiple ways:

First, if we /do/ have a transaction, we must NOT drop the inode,
because the inode could have dirty pages, dropping the inode will
trigger writeback, and writeback can trigger a nested transaction.

Second, if the inode already had an active reference and the DONTCACHE
flag set, the icache hit when scrub grabs another ref will not clear
DONTCACHE.  This is sort of by design, since DONTCACHE is now used to
initiate cache drops so that sysadmins can change a file's access mode
between pagecache and DAX.

Third, if we do actually have the last active reference to the inode, we
can set DONTCACHE to avoid polluting the cache.  This is the /one/ case
where we actually want that flag.

Create an xchk_irele helper to encode all that logic and switch the
online fsck code to use it.  Since this now means that nearly all
scrubbers use the same xfs_iget flags, we can wrap them too.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-11 19:00:20 -07:00
Darrick J. Wong
88accf1722 xfs: scrub should use ECHRNG to signal that the drain is needed
In the previous patch, we added jump labels to the intent drain code so
that regular filesystem operations need not pay the price of checking
for someone (scrub) waiting on intents to drain from some part of the
filesystem when that someone isn't running.

However, I observed that xfs/285 now spends a lot more time pushing the
AIL from the inode btree scrubber than it used to.  This is because the
inobt scrubber will try push the AIL to try to get logged inode cores
written to the filesystem when it sees a weird discrepancy between the
ondisk inode and the inobt records.  This AIL push is triggered when the
setup function sees TRY_HARDER is set; and the requisite EDEADLOCK
return is initiated when the discrepancy is seen.

The solution to this performance slow down is to use a different result
code (ECHRNG) for scrub code to signal that it needs to wait for
deferred intent work items to drain out of some part of the filesystem.
When this happens, set a new scrub state flag (XCHK_NEED_DRAIN) so that
setup functions will activate the jump label.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-11 19:00:00 -07:00
Darrick J. Wong
466c525d6d xfs: minimize overhead of drain wakeups by using jump labels
To reduce the runtime overhead even further when online fsck isn't
running, use a static branch key to decide if we call wake_up on the
drain.  For compilers that support jump labels, the call to wake_up is
replaced by a nop sled when nobody is waiting for intents to drain.

From my initial microbenchmarking, every transition of the static key
between the on and off states takes about 22000ns to complete; this is
paid entirely by the xfs_scrub process.  When the static key is off
(which it should be when fsck isn't running), the nop sled adds an
overhead of approximately 0.36ns to runtime code.  The post-atomic
lockless waiter check adds about 0.03ns, which is basically free.

For the few compilers that don't support jump labels, runtime code pays
the cost of calling wake_up on an empty waitqueue, which was observed to
be about 30ns.  However, most architectures that have sufficient memory
and CPU capacity to run XFS also support jump labels, so this is not
much of a worry.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-11 18:59:59 -07:00
Darrick J. Wong
3f64c718d0 xfs: clean up scrub context if scrub setup returns -EDEADLOCK
It has been a longstanding convention that online scrub and repair
functions can return -EDEADLOCK to signal that they weren't able to
obtain some necessary resource.  When this happens, the scrub framework
is supposed to release all resources attached to the scrub context, set
the TRY_HARDER flag in the scrub context flags, and try again.  In this
context, individual scrub functions are supposed to take all the
resources they (incorrectly) speculated were not necessary.

We're about to make it so that the functions that lock and wait for a
filesystem AG can also return EDEADLOCK to signal that we need to try
again with the drain waiters enabled.  Therefore, refactor
xfs_scrub_metadata to support this behavior for ->setup() functions.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-11 18:59:59 -07:00
Darrick J. Wong
ecc73f8a58 xfs: update copyright years for scrub/ files
Update the copyright years in the scrub/ source code files.  This isn't
required, but it's helpful to remind myself just how long it's taken to
develop this feature.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-11 18:59:57 -07:00
Darrick J. Wong
739a2fe042 xfs: fix author and spdx headers on scrub/ files
Fix the spdx tags to match current practice, and update the author
contact information.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-11 18:59:56 -07:00
Darrick J. Wong
306195f355 xfs: pivot online scrub away from kmem.[ch]
Convert all the online scrub code to use the Linux slab allocator
functions directly instead of going through the kmem wrappers.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-11-16 15:25:02 -08:00
Darrick J. Wong
df5660cf63 xfs: implement per-mount warnings for scrub and shrink usage
Currently, we don't have a consistent story around logging when an
EXPERIMENTAL feature gets turned on at runtime -- online fsck and shrink
log a message once per day across all mounts, and the recently merged
LARP mode only ever does it once per insmod cycle or reboot.

Because EXPERIMENTAL tags are supposed to go away eventually, convert
the existing daily warnings into state flags that travel with the mount,
and warn once per mount.  Making this an opstate flag means that we'll
be able to capture the experimental usage in the ftrace output too.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2022-05-27 10:31:34 +10:00
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
510a28e195 xfs: don't allocate scrub contexts on the stack
Convert the on-stack scrub context, btree scrub context, and da btree
scrub context into a heap allocation so that we reduce stack usage and
gain the ability to handle tall btrees without issue.

Specifically, this saves us ~208 bytes for the dabtree scrub, ~464 bytes
for the btree scrub, and ~200 bytes for the main scrub context.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2021-10-14 09:19:32 -07:00
Dave Chinner
55fafb31f9 xfs: convert scrub to use mount-based feature checks
The scrub feature checks are the last place that the superblock
feature checks are used. Convert them to mount based feature checks.

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>
2021-08-19 10:07:13 -07:00
Dave Chinner
75c8c50fa1 xfs: replace XFS_FORCED_SHUTDOWN with xfs_is_shutdown
Remove the shouty macro and instead use the inline function that
matches other state/feature check wrapper naming. This conversion
was done with sed.

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>
2021-08-19 10:07:13 -07:00
Dave Chinner
2e973b2cd4 xfs: convert remaining mount flags to state flags
The remaining mount flags kept in m_flags are actually runtime state
flags. These change dynamically, so they really should be updated
atomically so we don't potentially lose an update due to racing
modifications.

Convert these remaining flags to be stored in m_opstate and use
atomic bitops to set and clear the flags. This also adds a couple of
simple wrappers for common state checks - read only and shutdown.

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>
2021-08-19 10:07:13 -07:00
Dave Chinner
0560f31a09 xfs: convert mount flags to features
Replace m_flags feature checks with xfs_has_<feature>() calls and
rework the setup code to set flags in m_features.

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>
2021-08-19 10:07:12 -07:00
Dave Chinner
38c26bfd90 xfs: replace xfs_sb_version checks with feature flag checks
Convert the xfs_sb_version_hasfoo() to checks against
mp->m_features. Checks of the superblock itself during disk
operations (e.g. in the read/write verifiers and the to/from disk
formatters) are not converted - they operate purely on the
superblock state. Everything else should use the mount features.

Large parts of this conversion were done with sed with commands like
this:

for f in `git grep -l xfs_sb_version_has fs/xfs/*.c`; do
	sed -i -e 's/xfs_sb_version_has\(.*\)(&\(.*\)->m_sb)/xfs_has_\1(\2)/' $f
done

With manual cleanups for things like "xfs_has_extflgbit" and other
little inconsistencies in naming.

The result is ia lot less typing to check features and an XFS binary
size reduced by a bit over 3kB:

$ size -t fs/xfs/built-in.a
	text	   data	    bss	    dec	    hex	filenam
before	1130866  311352     484 1442702  16038e (TOTALS)
after	1127727  311352     484 1439563  15f74b (TOTALS)

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-08-19 10:07:12 -07:00
Darrick J. Wong
54406764c6 xfs: remove unnecessary agno variable from struct xchk_ag
Now that we always grab an active reference to a perag structure when
dealing with perag metadata, we can remove this unnecessary variable.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2021-08-18 18:46:00 -07:00
Darrick J. Wong
026f57ebe1 xfs: get rid of the ip parameter to xchk_setup_*
Now that the scrub context stores a pointer to the file that was used to
invoke the scrub call, the struct xfs_inode pointer that we passed to
all the setup functions is no longer necessary.  This is only ever used
if the caller wants us to scrub the metadata of the open file.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2021-04-09 10:27:18 -07:00