<feed xmlns='http://www.w3.org/2005/Atom'>
<title>starfive-tech/linux.git/fs/xfs, branch rt-linux-release</title>
<subtitle>StarFive Tech Linux Kernel for VisionFive (JH7110) boards (mirror)</subtitle>
<id>https://git.radix-linux.su/starfive-tech/linux.git/atom?h=rt-linux-release</id>
<link rel='self' href='https://git.radix-linux.su/starfive-tech/linux.git/atom?h=rt-linux-release'/>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/starfive-tech/linux.git/'/>
<updated>2021-09-09T18:39:57+00:00</updated>
<entry>
<title>Merge tag 'libnvdimm-for-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm</title>
<updated>2021-09-09T18:39:57+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-09-09T18:39:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/starfive-tech/linux.git/commit/?id=2e5fd489a4e5fcc97b035c03ace724c1d481a4c1'/>
<id>urn:sha1:2e5fd489a4e5fcc97b035c03ace724c1d481a4c1</id>
<content type='text'>
Pull libnvdimm updates from Dan Williams:

 - Fix a race condition in the teardown path of raw mode pmem
   namespaces.

 - Cleanup the code that filesystems use to detect filesystem-dax
   capabilities of their underlying block device.

* tag 'libnvdimm-for-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  dax: remove bdev_dax_supported
  xfs: factor out a xfs_buftarg_is_dax helper
  dax: stub out dax_supported for !CONFIG_FS_DAX
  dax: remove __generic_fsdax_supported
  dax: move the dax_read_lock() locking into dax_supported
  dax: mark dax_get_by_host static
  dm: use fs_dax_get_by_bdev instead of dax_get_by_host
  dax: stop using bdevname
  fsdax: improve the FS_DAX Kconfig description and help text
  libnvdimm/pmem: Fix crash triggered when I/O in-flight during unbind
</content>
</entry>
<entry>
<title>Merge tag 'ovl-update-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs</title>
<updated>2021-09-02T16:21:27+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-09-02T16:21:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/starfive-tech/linux.git/commit/?id=815409a12c0a9c0de17a910fd95fe11e1eb97f32'/>
<id>urn:sha1:815409a12c0a9c0de17a910fd95fe11e1eb97f32</id>
<content type='text'>
Pull overlayfs update from Miklos Szeredi:

 - Copy up immutable/append/sync/noatime attributes (Amir Goldstein)

 - Improve performance by enabling RCU lookup.

 - Misc fixes and improvements

The reason this touches so many files is that the -&gt;get_acl() method now
gets a "bool rcu" argument.  The -&gt;get_acl() API was updated based on
comments from Al and Linus:

Link: https://lore.kernel.org/linux-fsdevel/CAJfpeguQxpd6Wgc0Jd3ks77zcsAv_bn0q17L3VNnnmPKu11t8A@mail.gmail.com/

* tag 'ovl-update-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  ovl: enable RCU'd -&gt;get_acl()
  vfs: add rcu argument to -&gt;get_acl() callback
  ovl: fix BUG_ON() in may_delete() when called from ovl_cleanup()
  ovl: use kvalloc in xattr copy-up
  ovl: update ctime when changing fileattr
  ovl: skip checking lower file's i_writecount on truncate
  ovl: relax lookup error on mismatch origin ftype
  ovl: do not set overlay.opaque for new directories
  ovl: add ovl_allow_offline_changes() helper
  ovl: disable decoding null uuid with redirect_dir
  ovl: consistent behavior for immutable/append-only inodes
  ovl: copy up sync/noatime fileattr flags
  ovl: pass ovl_fs to ovl_check_setxattr()
  fs: add generic helper for filling statx attribute flags
</content>
</entry>
<entry>
<title>Merge tag 'xfs-5.15-merge-6' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux</title>
<updated>2021-09-02T15:26:03+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-09-02T15:26:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/starfive-tech/linux.git/commit/?id=90c90cda05aecf0f7c45f9f35384b31bba38455f'/>
<id>urn:sha1:90c90cda05aecf0f7c45f9f35384b31bba38455f</id>
<content type='text'>
Pull xfs updates from Darrick Wong:
 "There's a lot in this cycle.

  Starting with bug fixes: To avoid livelocks between the logging code
  and the quota code, we've disabled the ability of quotaoff to turn off
  quota accounting. (Admins can still disable quota enforcement, but
  truly turning off accounting requires a remount.) We've tried to do
  this in a careful enough way that there shouldn't be any user visible
  effects aside from quotaoff no longer randomly hanging the system.

  We've also fixed some bugs in runtime log behavior that could trip up
  log recovery if (otherwise unrelated) transactions manage to start and
  commit concurrently; some bugs in the GETFSMAP ioctl where we would
  incorrectly restrict the range of records output if the two xfs
  devices are of different sizes; a bug that resulted in fallocate
  funshare failing unnecessarily; and broken behavior in the xfs inode
  cache when DONTCACHE is in play.

  As for new features: we now batch inode inactivations in percpu
  background threads, which sharply decreases frontend thread wait time
  when performing file deletions and should improve overall directory
  tree deletion times. This eliminates both the problem where closing an
  unlinked file (especially on a frozen fs) can stall for a long time,
  and should also ease complaints about direct reclaim bogging down on
  unlinked file cleanup.

  Starting with this release, we've enabled pipelining of the XFS log.
  On workloads with high rates of metadata updates to different shards
  of the filesystem, multiple threads can be used to format committed
  log updates into log checkpoints.

  Lastly, with this release, two new features have graduated to
  supported status: inode btree counters (for faster mounts), and
  support for dates beyond Y2038. Expect these to be enabled by default
  in a future release of xfsprogs.

  Summary:

   - Fix a potential log livelock on busy filesystems when there's so
     much work going on that we can't finish a quotaoff before filling
     up the log by removing the ability to disable quota accounting.

   - Introduce the ability to use per-CPU data structures in XFS so that
     we can do a better job of maintaining CPU locality for certain
     operations.

   - Defer inode inactivation work to per-CPU lists, which will help us
     batch that processing. Deletions of large sparse files will
     *appear* to run faster, but all that means is that we've moved the
     work to the backend.

   - Drop the EXPERIMENTAL warnings from the y2038+ support and the
     inode btree counters, since it's been nearly a year and no
     complaints have come in.

   - Remove more of our bespoke kmem* variants in favor of using the
     standard Linux calls.

   - Prepare for the addition of log incompat features in upcoming
     cycles by actually adding code to support this.

   - Small cleanups of the xattr code in preparation for landing support
     for full logging of extended attribute updates in a future cycle.

   - Replace the various log shutdown state and flag code all over xfs
     with a single atomic bit flag.

   - Fix a serious log recovery bug where log item replay can be skipped
     based on the start lsn of a transaction even though the transaction
     commit lsn is the key data point for that by enforcing start lsns
     to appear in the log in the same order as commit lsns.

   - Enable pipelining in the code that pushes log items to disk.

   - Drop -&gt;writepage.

   - Fix some bugs in GETFSMAP where the last fsmap record reported for
     a device could extend beyond the end of the device, and a separate
     bug where query keys for one device could be applied to another.

   - Don't let GETFSMAP query functions edit their input parameters.

   - Small cleanups to the scrub code's handling of perag structures.

   - Small cleanups to the incore inode tree walk code.

   - Constify btree function parameters that aren't changed, so that
     there will never again be confusion about range query functions
     changing their input parameters.

   - Standardize the format and names of tracepoint data attributes.

   - Clean up all the mount state and feature flags to use wrapped
     bitset functions instead of inconsistently open-coded flag checks.

   - Fix some confusion between xfs_buf hash table key variable vs.
     block number.

   - Fix a mis-interaction with iomap where we reported shared delalloc
     cow fork extents to iomap, which would cause the iomap unshare
     operation to return IO errors unnecessarily.

   - Fix DONTCACHE behavior"

* tag 'xfs-5.15-merge-6' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (103 commits)
  xfs: fix I_DONTCACHE
  xfs: only set IOMAP_F_SHARED when providing a srcmap to a write
  xfs: fix perag structure refcounting error when scrub fails
  xfs: rename buffer cache index variable b_bn
  xfs: convert bp-&gt;b_bn references to xfs_buf_daddr()
  xfs: introduce xfs_buf_daddr()
  xfs: kill xfs_sb_version_has_v3inode()
  xfs: introduce xfs_sb_is_v5 helper
  xfs: remove unused xfs_sb_version_has wrappers
  xfs: convert xfs_sb_version_has checks to use mount features
  xfs: convert scrub to use mount-based feature checks
  xfs: open code sb verifier feature checks
  xfs: convert xfs_fs_geometry to use mount feature checks
  xfs: replace XFS_FORCED_SHUTDOWN with xfs_is_shutdown
  xfs: convert remaining mount flags to state flags
  xfs: convert mount flags to features
  xfs: consolidate mount option features in m_features
  xfs: replace xfs_sb_version checks with feature flag checks
  xfs: reflect sb features in xfs_mount
  xfs: rework attr2 feature and mount options
  ...
</content>
</entry>
<entry>
<title>Merge tag 'for-5.15/block-2021-08-30' of git://git.kernel.dk/linux-block</title>
<updated>2021-08-31T01:52:11+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-08-31T01:52:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/starfive-tech/linux.git/commit/?id=679369114e55f422dc593d0628cfde1d04ae59b3'/>
<id>urn:sha1:679369114e55f422dc593d0628cfde1d04ae59b3</id>
<content type='text'>
Pull block updates from Jens Axboe:
 "Nothing major in here - lots of good cleanups and tech debt handling,
  which is also evident in the diffstats. In particular:

   - Add disk sequence numbers (Matteo)

   - Discard merge fix (Ming)

   - Relax disk zoned reporting restrictions (Niklas)

   - Bio error handling zoned leak fix (Pavel)

   - Start of proper add_disk() error handling (Luis, Christoph)

   - blk crypto fix (Eric)

   - Non-standard GPT location support (Dmitry)

   - IO priority improvements and cleanups (Damien)o

   - blk-throtl improvements (Chunguang)

   - diskstats_show() stack reduction (Abd-Alrhman)

   - Loop scheduler selection (Bart)

   - Switch block layer to use kmap_local_page() (Christoph)

   - Remove obsolete disk_name helper (Christoph)

   - block_device refcounting improvements (Christoph)

   - Ensure gendisk always has a request queue reference (Christoph)

   - Misc fixes/cleanups (Shaokun, Oliver, Guoqing)"

* tag 'for-5.15/block-2021-08-30' of git://git.kernel.dk/linux-block: (129 commits)
  sg: pass the device name to blk_trace_setup
  block, bfq: cleanup the repeated declaration
  blk-crypto: fix check for too-large dun_bytes
  blk-zoned: allow BLKREPORTZONE without CAP_SYS_ADMIN
  blk-zoned: allow zone management send operations without CAP_SYS_ADMIN
  block: mark blkdev_fsync static
  block: refine the disk_live check in del_gendisk
  mmc: sdhci-tegra: Enable MMC_CAP2_ALT_GPT_TEGRA
  mmc: block: Support alternative_gpt_sector() operation
  partitions/efi: Support non-standard GPT location
  block: Add alternative_gpt_sector() operation
  bio: fix page leak bio_add_hw_page failure
  block: remove CONFIG_DEBUG_BLOCK_EXT_DEVT
  block: remove a pointless call to MINOR() in device_add_disk
  null_blk: add error handling support for add_disk()
  virtio_blk: add error handling support for add_disk()
  block: add error handling for device_add_disk / add_disk
  block: return errors from disk_alloc_events
  block: return errors from blk_integrity_add
  block: call blk_register_queue earlier in device_add_disk
  ...
</content>
</entry>
<entry>
<title>Merge tag 'hole_punch_for_v5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs</title>
<updated>2021-08-30T17:24:50+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-08-30T17:24:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/starfive-tech/linux.git/commit/?id=aa99f3c2b9c797d8fee28c674a2cbb5adb2ce2ef'/>
<id>urn:sha1:aa99f3c2b9c797d8fee28c674a2cbb5adb2ce2ef</id>
<content type='text'>
Pull fs hole punching vs cache filling race fixes from Jan Kara:
 "Fix races leading to possible data corruption or stale data exposure
  in multiple filesystems when hole punching races with operations such
  as readahead.

  This is the series I was sending for the last merge window but with
  your objection fixed - now filemap_fault() has been modified to take
  invalidate_lock only when we need to create new page in the page cache
  and / or bring it uptodate"

* tag 'hole_punch_for_v5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  filesystems/locking: fix Malformed table warning
  cifs: Fix race between hole punch and page fault
  ceph: Fix race between hole punch and page fault
  fuse: Convert to using invalidate_lock
  f2fs: Convert to using invalidate_lock
  zonefs: Convert to using invalidate_lock
  xfs: Convert double locking of MMAPLOCK to use VFS helpers
  xfs: Convert to use invalidate_lock
  xfs: Refactor xfs_isilocked()
  ext2: Convert to using invalidate_lock
  ext4: Convert to use mapping-&gt;invalidate_lock
  mm: Add functions to lock invalidate_lock for two mappings
  mm: Protect operations adding pages to page cache with invalidate_lock
  documentation: Sync file_operations members with reality
  mm: Fix comments mentioning i_mutex
</content>
</entry>
<entry>
<title>dax: remove bdev_dax_supported</title>
<updated>2021-08-26T23:52:03+00:00</updated>
<author>
<name>Christoph Hellwig</name>
<email>hch@lst.de</email>
</author>
<published>2021-08-26T13:55:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/starfive-tech/linux.git/commit/?id=bdd3c50d83bf7f6acc869b48d02670d19030ae03'/>
<id>urn:sha1:bdd3c50d83bf7f6acc869b48d02670d19030ae03</id>
<content type='text'>
All callers already have a dax_device obtained from fs_dax_get_by_bdev
at hand, so just pass that to dax_supported() insted of doing another
lookup.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Link: https://lore.kernel.org/r/20210826135510.6293-10-hch@lst.de
Signed-off-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
</content>
</entry>
<entry>
<title>xfs: factor out a xfs_buftarg_is_dax helper</title>
<updated>2021-08-26T23:52:03+00:00</updated>
<author>
<name>Christoph Hellwig</name>
<email>hch@lst.de</email>
</author>
<published>2021-08-26T13:55:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/starfive-tech/linux.git/commit/?id=a384f088e4a102b97a59bc0fdaf8b60bca177679'/>
<id>urn:sha1:a384f088e4a102b97a59bc0fdaf8b60bca177679</id>
<content type='text'>
Refactor the DAX setup code in preparation of removing
bdev_dax_supported.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Reviewed-by: Darrick J. Wong &lt;djwong@kernel.org&gt;
Link: https://lore.kernel.org/r/20210826135510.6293-9-hch@lst.de
Signed-off-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
</content>
</entry>
<entry>
<title>xfs: fix I_DONTCACHE</title>
<updated>2021-08-25T02:13:04+00:00</updated>
<author>
<name>Dave Chinner</name>
<email>dchinner@redhat.com</email>
</author>
<published>2021-08-25T02:13:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/starfive-tech/linux.git/commit/?id=f38a032b165d812b0ba8378a5cd237c0888ff65f'/>
<id>urn:sha1:f38a032b165d812b0ba8378a5cd237c0888ff65f</id>
<content type='text'>
Yup, the VFS hoist broke it, and nobody noticed. Bulkstat workloads
make it clear that it doesn't work as it should.

Fixes: dae2f8ed7992 ("fs: Lift XFS_IDONTCACHE to the VFS layer")
Signed-off-by: Dave Chinner &lt;dchinner@redhat.com&gt;
Reviewed-by: Darrick J. Wong &lt;djwong@kernel.org&gt;
Signed-off-by: Darrick J. Wong &lt;djwong@kernel.org&gt;
</content>
</entry>
<entry>
<title>xfs: only set IOMAP_F_SHARED when providing a srcmap to a write</title>
<updated>2021-08-24T00:32:51+00:00</updated>
<author>
<name>Darrick J. Wong</name>
<email>djwong@kernel.org</email>
</author>
<published>2021-08-20T21:42:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/starfive-tech/linux.git/commit/?id=72a048c1056a72e37ea2ee34cc73d8c6d6cb4290'/>
<id>urn:sha1:72a048c1056a72e37ea2ee34cc73d8c6d6cb4290</id>
<content type='text'>
While prototyping a free space defragmentation tool, I observed an
unexpected IO error while running a sequence of commands that can be
recreated by the following sequence of commands:

# xfs_io -f -c "pwrite -S 0x58 -b 10m 0 10m" file1
# cp --reflink=always file1 file2
# punch-alternating -o 1 file2
# xfs_io -c "funshare 0 10m" file2
fallocate: Input/output error

I then scraped this (abbreviated) stack trace from dmesg:

WARNING: CPU: 0 PID: 30788 at fs/iomap/buffered-io.c:577 iomap_write_begin+0x376/0x450
CPU: 0 PID: 30788 Comm: xfs_io Not tainted 5.14.0-rc6-xfsx #rc6 5ef57b62a900814b3e4d885c755e9014541c8732
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:iomap_write_begin+0x376/0x450
RSP: 0018:ffffc90000c0fc20 EFLAGS: 00010297
RAX: 0000000000000001 RBX: ffffc90000c0fd10 RCX: 0000000000001000
RDX: ffffc90000c0fc54 RSI: 000000000000000c RDI: 000000000000000c
RBP: ffff888005d5dbd8 R08: 0000000000102000 R09: ffffc90000c0fc50
R10: 0000000000b00000 R11: 0000000000101000 R12: ffffea0000336c40
R13: 0000000000001000 R14: ffffc90000c0fd10 R15: 0000000000101000
FS:  00007f4b8f62fe40(0000) GS:ffff88803ec00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056361c554108 CR3: 000000000524e004 CR4: 00000000001706f0
Call Trace:
 iomap_unshare_actor+0x95/0x140
 iomap_apply+0xfa/0x300
 iomap_file_unshare+0x44/0x60
 xfs_reflink_unshare+0x50/0x140 [xfs 61947ea9b3a73e79d747dbc1b90205e7987e4195]
 xfs_file_fallocate+0x27c/0x610 [xfs 61947ea9b3a73e79d747dbc1b90205e7987e4195]
 vfs_fallocate+0x133/0x330
 __x64_sys_fallocate+0x3e/0x70
 do_syscall_64+0x35/0x80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f4b8f79140a

Looking at the iomap tracepoints, I saw this:

iomap_iter:           dev 8:64 ino 0x100 pos 0 length 0 flags WRITE|0x80 (0x81) ops xfs_buffered_write_iomap_ops caller iomap_file_unshare
iomap_iter_dstmap:    dev 8:64 ino 0x100 bdev 8:64 addr -1 offset 0 length 131072 type DELALLOC flags SHARED
iomap_iter_srcmap:    dev 8:64 ino 0x100 bdev 8:64 addr 147456 offset 0 length 4096 type MAPPED flags
iomap_iter:           dev 8:64 ino 0x100 pos 0 length 4096 flags WRITE|0x80 (0x81) ops xfs_buffered_write_iomap_ops caller iomap_file_unshare
iomap_iter_dstmap:    dev 8:64 ino 0x100 bdev 8:64 addr -1 offset 4096 length 4096 type DELALLOC flags SHARED
console:              WARNING: CPU: 0 PID: 30788 at fs/iomap/buffered-io.c:577 iomap_write_begin+0x376/0x450

The first time funshare calls -&gt;iomap_begin, xfs sees that the first
block is shared and creates a 128k delalloc reservation in the COW fork.
The delalloc reservation is returned as dstmap, and the shared block is
returned as srcmap.  So far so good.

funshare calls -&gt;iomap_begin to try the second block.  This time there's
no srcmap (punch-alternating punched it out!) but we still have the
delalloc reservation in the COW fork.  Therefore, we again return the
reservation as dstmap and the hole as srcmap.  iomap_unshare_iter
incorrectly tries to unshare the hole, which __iomap_write_begin rejects
because shared regions must be fully written and therefore cannot
require zeroing.

Therefore, change the buffered write iomap_begin function not to set
IOMAP_F_SHARED when there isn't a source mapping to read from for the
unsharing.

Signed-off-by: Darrick J. Wong &lt;djwong@kernel.org&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Chandan Babu R &lt;chandanrlinux@gmail.com&gt;
</content>
</entry>
<entry>
<title>xfs: fix perag structure refcounting error when scrub fails</title>
<updated>2021-08-20T20:20:33+00:00</updated>
<author>
<name>Darrick J. Wong</name>
<email>djwong@kernel.org</email>
</author>
<published>2021-08-19T19:07:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/starfive-tech/linux.git/commit/?id=61e0d0cc51cd6b9d7447923f3ac7e60049de3e2e'/>
<id>urn:sha1:61e0d0cc51cd6b9d7447923f3ac7e60049de3e2e</id>
<content type='text'>
The kernel test robot found the following bug when running xfs/355 to
scrub a bmap btree:

XFS: Assertion failed: !sa-&gt;pag, file: fs/xfs/scrub/common.c, line: 412
------------[ cut here ]------------
kernel BUG at fs/xfs/xfs_message.c:110!
invalid opcode: 0000 [#1] SMP PTI
CPU: 2 PID: 1415 Comm: xfs_scrub Not tainted 5.14.0-rc4-00021-g48c6615cc557 #1
Hardware name: Hewlett-Packard p6-1451cx/2ADA, BIOS 8.15 02/05/2013
RIP: 0010:assfail+0x23/0x28 [xfs]
RSP: 0018:ffffc9000aacb890 EFLAGS: 00010202
RAX: 0000000000000000 RBX: ffffc9000aacbcc8 RCX: 0000000000000000
RDX: 00000000ffffffc0 RSI: 000000000000000a RDI: ffffffffc09e7dcd
RBP: ffffc9000aacbc80 R08: ffff8881fdf17d50 R09: 0000000000000000
R10: 000000000000000a R11: f000000000000000 R12: 0000000000000000
R13: ffff88820c7ed000 R14: 0000000000000001 R15: ffffc9000aacb980
FS:  00007f185b955700(0000) GS:ffff8881fdf00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7f6ef43000 CR3: 000000020de38002 CR4: 00000000001706e0
Call Trace:
 xchk_ag_read_headers+0xda/0x100 [xfs]
 xchk_ag_init+0x15/0x40 [xfs]
 xchk_btree_check_block_owner+0x76/0x180 [xfs]
 xchk_btree_get_block+0xd0/0x140 [xfs]
 xchk_btree+0x32e/0x440 [xfs]
 xchk_bmap_btree+0xd4/0x140 [xfs]
 xchk_bmap+0x1eb/0x3c0 [xfs]
 xfs_scrub_metadata+0x227/0x4c0 [xfs]
 xfs_ioc_scrub_metadata+0x50/0xc0 [xfs]
 xfs_file_ioctl+0x90c/0xc40 [xfs]
 __x64_sys_ioctl+0x83/0xc0
 do_syscall_64+0x3b/0xc0

The unusual handling of errors while initializing struct xchk_ag is the
root cause here.  Since the beginning of xfs_scrub, the goal of
xchk_ag_read_headers has been to read all three AG header buffers and
attach them both to the xchk_ag structure and the scrub transaction.
Corruption errors on any of the three headers doesn't necessarily
trigger an immediate return to userspace, because xfs_scrub can also
tell us to /fix/ the problem.

In other words, it's possible for the xchk_ag init functions to return
an error code and a partially filled out structure so that scrub can use
however much information it managed to pull.  Before 5.15, it was
sufficient to cancel (or commit) the scrub transaction on the way out of
the scrub code to release the buffers.

Ccommit 48c6615cc557 added a reference to the perag structure to struct
xchk_ag.  Since perag structures are not attached to transactions like
buffers are, this adds the requirement that the perag ref be released
explicitly.  The scrub teardown function xchk_teardown was amended to do
this for the xchk_ag embedded in struct xfs_scrub.

Unfortunately, I forgot that certain parts of the scrub code probe
multiple AGs and therefore handle the initialization and cleanup on
their own.  Specifically, the bmbt scrubber will initialize it long
enough to cross-reference AG metadata for btree blocks and for the
extent mappings in the bmbt.

If one of the AG headers is corrupt, the init function returns with a
live perag structure reference and some of the AG header buffers.  If an
error occurs, the cross referencing will be noted as XCORRUPTion and
skipped, but the main scrub process will move on to the next record.
It is now necessary to release the perag reference before we try to
analyze something from a different AG, or else we'll trip over the
assertion noted above.

Fixes: 48c6615cc557 ("xfs: grab active perag ref when reading AG headers")
Reported-by: kernel test robot &lt;oliver.sang@intel.com&gt;
Signed-off-by: Darrick J. Wong &lt;djwong@kernel.org&gt;
Reviewed-by: Chandan Babu R &lt;chandanrlinux@gmail.com&gt;
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