Commit Graph

7683 Commits

Author SHA1 Message Date
Andreas Gruenbacher
471859f57d iomap: Rename page_ops to folio_ops
The operations in struct page_ops all operate on folios, so rename
struct page_ops to struct folio_ops.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
[djwong: port around not removing iomap_valid]
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2023-01-18 10:44:05 -08:00
Wengang Wang
601a27ea09 xfs: fix extent busy updating
In xfs_extent_busy_update_extent() case 6 and 7, whenever bno is modified on
extent busy, the relavent length has to be modified accordingly.

Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2023-01-05 07:34:21 -08:00
Li zeming
e195605ed2 xfs: xfs_qm: remove unnecessary ‘0’ values from error
error is assigned first, so it does not need to initialize the
assignment.

Signed-off-by: Li zeming <zeming@nfschina.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2023-01-03 10:23:07 -08:00
Wu Guanghao
4da112513c xfs: Fix deadlock on xfs_inodegc_worker
We are doing a test about deleting a large number of files
when memory is low. A deadlock problem was found.

[ 1240.279183] -> #1 (fs_reclaim){+.+.}-{0:0}:
[ 1240.280450]        lock_acquire+0x197/0x460
[ 1240.281548]        fs_reclaim_acquire.part.0+0x20/0x30
[ 1240.282625]        kmem_cache_alloc+0x2b/0x940
[ 1240.283816]        xfs_trans_alloc+0x8a/0x8b0
[ 1240.284757]        xfs_inactive_ifree+0xe4/0x4e0
[ 1240.285935]        xfs_inactive+0x4e9/0x8a0
[ 1240.286836]        xfs_inodegc_worker+0x160/0x5e0
[ 1240.287969]        process_one_work+0xa19/0x16b0
[ 1240.289030]        worker_thread+0x9e/0x1050
[ 1240.290131]        kthread+0x34f/0x460
[ 1240.290999]        ret_from_fork+0x22/0x30
[ 1240.291905]
[ 1240.291905] -> #0 ((work_completion)(&gc->work)){+.+.}-{0:0}:
[ 1240.293569]        check_prev_add+0x160/0x2490
[ 1240.294473]        __lock_acquire+0x2c4d/0x5160
[ 1240.295544]        lock_acquire+0x197/0x460
[ 1240.296403]        __flush_work+0x6bc/0xa20
[ 1240.297522]        xfs_inode_mark_reclaimable+0x6f0/0xdc0
[ 1240.298649]        destroy_inode+0xc6/0x1b0
[ 1240.299677]        dispose_list+0xe1/0x1d0
[ 1240.300567]        prune_icache_sb+0xec/0x150
[ 1240.301794]        super_cache_scan+0x2c9/0x480
[ 1240.302776]        do_shrink_slab+0x3f0/0xaa0
[ 1240.303671]        shrink_slab+0x170/0x660
[ 1240.304601]        shrink_node+0x7f7/0x1df0
[ 1240.305515]        balance_pgdat+0x766/0xf50
[ 1240.306657]        kswapd+0x5bd/0xd20
[ 1240.307551]        kthread+0x34f/0x460
[ 1240.308346]        ret_from_fork+0x22/0x30
[ 1240.309247]
[ 1240.309247] other info that might help us debug this:
[ 1240.309247]
[ 1240.310944]  Possible unsafe locking scenario:
[ 1240.310944]
[ 1240.312379]        CPU0                    CPU1
[ 1240.313363]        ----                    ----
[ 1240.314433]   lock(fs_reclaim);
[ 1240.315107]                                lock((work_completion)(&gc->work));
[ 1240.316828]                                lock(fs_reclaim);
[ 1240.318088]   lock((work_completion)(&gc->work));
[ 1240.319203]
[ 1240.319203]  *** DEADLOCK ***
...
[ 2438.431081] Workqueue: xfs-inodegc/sda xfs_inodegc_worker
[ 2438.432089] Call Trace:
[ 2438.432562]  __schedule+0xa94/0x1d20
[ 2438.435787]  schedule+0xbf/0x270
[ 2438.436397]  schedule_timeout+0x6f8/0x8b0
[ 2438.445126]  wait_for_completion+0x163/0x260
[ 2438.448610]  __flush_work+0x4c4/0xa40
[ 2438.455011]  xfs_inode_mark_reclaimable+0x6ef/0xda0
[ 2438.456695]  destroy_inode+0xc6/0x1b0
[ 2438.457375]  dispose_list+0xe1/0x1d0
[ 2438.458834]  prune_icache_sb+0xe8/0x150
[ 2438.461181]  super_cache_scan+0x2b3/0x470
[ 2438.461950]  do_shrink_slab+0x3cf/0xa50
[ 2438.462687]  shrink_slab+0x17d/0x660
[ 2438.466392]  shrink_node+0x87e/0x1d40
[ 2438.467894]  do_try_to_free_pages+0x364/0x1300
[ 2438.471188]  try_to_free_pages+0x26c/0x5b0
[ 2438.473567]  __alloc_pages_slowpath.constprop.136+0x7aa/0x2100
[ 2438.482577]  __alloc_pages+0x5db/0x710
[ 2438.485231]  alloc_pages+0x100/0x200
[ 2438.485923]  allocate_slab+0x2c0/0x380
[ 2438.486623]  ___slab_alloc+0x41f/0x690
[ 2438.490254]  __slab_alloc+0x54/0x70
[ 2438.491692]  kmem_cache_alloc+0x23e/0x270
[ 2438.492437]  xfs_trans_alloc+0x88/0x880
[ 2438.493168]  xfs_inactive_ifree+0xe2/0x4e0
[ 2438.496419]  xfs_inactive+0x4eb/0x8b0
[ 2438.497123]  xfs_inodegc_worker+0x16b/0x5e0
[ 2438.497918]  process_one_work+0xbf7/0x1a20
[ 2438.500316]  worker_thread+0x8c/0x1060
[ 2438.504938]  ret_from_fork+0x22/0x30

When the memory is insufficient, xfs_inonodegc_worker will trigger memory
reclamation when memory is allocated, then flush_work() may be called to
wait for the work to complete. This causes a deadlock.

So use memalloc_nofs_save() to avoid triggering memory reclamation in
xfs_inodegc_worker.

Signed-off-by: Wu Guanghao <wuguanghao3@huawei.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2023-01-03 10:23:07 -08:00
Hironori Shiina
817644fa45 xfs: get root inode correctly at bulkstat
The root inode number should be set to `breq->startino` for getting stat
information of the root when XFS_BULK_IREQ_SPECIAL_ROOT is used.
Otherwise, the inode search is started from 1
(XFS_BULK_IREQ_SPECIAL_ROOT) and the inode with the lowest number in a
filesystem is returned.

Fixes: bf3cb39447 ("xfs: allow single bulkstat of special inodes")
Signed-off-by: Hironori Shiina <shiina.hironori@fujitsu.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2023-01-03 10:23:07 -08:00
Darrick J. Wong
c0f399ff51 xfs: fix off-by-one error in xfs_btree_space_to_height
Lately I've been stress-testing extreme-sized rmap btrees by using the
(new) xfs_db bmap_inflate command to clone bmbt mappings billions of
times and then using xfs_repair to build new rmap and refcount btrees.
This of course is /much/ faster than actually FICLONEing a file billions
of times.

Unfortunately, xfs_repair fails in xfs_btree_bload_compute_geometry with
EOVERFLOW, which indicates that xfs_mount.m_rmap_maxlevels is not
sufficiently large for the test scenario.  For a 1TB filesystem (~67
million AG blocks, 4 AGs) the btheight command reports:

$ xfs_db -c 'btheight -n 4400801200 -w min rmapbt' /dev/sda
rmapbt: worst case per 4096-byte block: 84 records (leaf) / 45 keyptrs (node)
level 0: 4400801200 records, 52390491 blocks
level 1: 52390491 records, 1164234 blocks
level 2: 1164234 records, 25872 blocks
level 3: 25872 records, 575 blocks
level 4: 575 records, 13 blocks
level 5: 13 records, 1 block
6 levels, 53581186 blocks total

The AG is sufficiently large to build this rmap btree.  Unfortunately,
m_rmap_maxlevels is 5.  Augmenting the loop in the space->height
function to report height, node blocks, and blocks remaining produces
this:

ht 1 node_blocks 45 blockleft 67108863
ht 2 node_blocks 2025 blockleft 67108818
ht 3 node_blocks 91125 blockleft 67106793
ht 4 node_blocks 4100625 blockleft 67015668
final height: 5

The goal of this function is to compute the maximum height btree that
can be stored in the given number of ondisk fsblocks.  Starting with the
top level of the tree, each iteration through the loop adds the fanout
factor of the next level down until we run out of blocks.  IOWs, maximum
height is achieved by using the smallest fanout factor that can apply
to that level.

However, the loop setup is not correct.  Top level btree blocks are
allowed to contain fewer than minrecs items, so the computation is
incorrect because the first time through the loop it should be using a
fanout factor of 2.  With this corrected, the above becomes:

ht 1 node_blocks 2 blockleft 67108863
ht 2 node_blocks 90 blockleft 67108861
ht 3 node_blocks 4050 blockleft 67108771
ht 4 node_blocks 182250 blockleft 67104721
ht 5 node_blocks 8201250 blockleft 66922471
final height: 6

Fixes: 9ec691205e ("xfs: compute the maximum height of the rmap btree when reflink enabled")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-01-03 10:23:07 -08:00
Darrick J. Wong
d4542f3145 xfs: make xfs_iomap_page_ops static
Shut up the sparse warnings about this variable that isn't referenced
anywhere else.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-12-26 10:11:18 -08:00
Darrick J. Wong
26870c3f5b xfs: don't assert if cmap covers imap after cycling lock
In xfs_reflink_fill_cow_hole, there's a debugging assertion that trips
if (after cycling the ILOCK to get a transaction) the requeried cow
mapping overlaps the start of the area being written.  IOWs, it trips if
the hole in the cow fork that it's supposed to fill has been filled.

This is trivially possible since we cycled ILOCK_EXCL.  If we trip the
assertion, then we know that cmap is a delalloc extent because @found is
false.  Fortunately, the bmapi_write call below will convert the
delalloc extent to a real unwritten cow fork extent, so all we need to
do here is remove the assertion.

It turns out that generic/095 trips this pretty regularly with alwayscow
mode enabled.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-12-26 10:11:17 -08:00
Linus Torvalds
87be949912 New XFS code for 6.2:
- Fix a race condition w.r.t. percpu inode free counters
  - Fix a broken error return in xfs_remove
  - Print FS UUID at mount/unmount time
  - Numerous fixes to the online fsck code
  - Fix inode locking inconsistency problems when dealing with realtime
    metadata files
  - Actually merge pull requests so that we capture the cover letter
    contents
  - Fix a race between rebuilding VFS inode state and the AIL flushing
    inodes that could cause corrupt inodes to be written to the
    filesystem
  - Fix a data corruption problem resulting from a write() to an
    unwritten extent racing with writeback started on behalf of memory
    reclaim changing the extent state
  - Add debugging knobs so that we can test iomap invalidation
  - Fix the blockdev pagecache contents being stale after unmounting the
    filesystem, leading to spurious xfs_db errors and corrupt metadumps
  - Fix a file mapping corruption bug due to ilock cycling when attaching
    dquots to a file during delalloc reservation
  - Fix a refcount btree corruption problem due to the refcount
    adjustment code not handling MAXREFCOUNT correctly, resulting in
    unnecessary record splits
  - Fix COW staging extent alloctions not being classified as USERDATA,
    which results in filestreams being ignored and possible data
    corruption if the allocation was filled from the AGFL and the block
    buffer is still being tracked in the AIL
  - Fix new duplicated includes
  - Fix a race between the dquot shrinker and dquot freeing that could
    cause a UAF
 
 Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Merge tag 'xfs-6.2-merge-8' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull XFS updates from Darrick Wong:
 "The highlight of this is a batch of fixes for the online metadata
  checking code as we start the loooong march towards merging online
  repair. I aim to merge that in time for the 2023 LTS.

  There are also a large number of data corruption and race condition
  fixes in this patchset. Most notably fixed are write() calls to
  unwritten extents racing with writeback, which required some late(r
  than I prefer) code changes to iomap to support the necessary
  revalidations. I don't really like iomap changes going in past -rc4,
  but Dave and I have been working on it long enough that I chose to
  push it for 6.2 anyway.

  There are also a number of other subtle problems fixed, including the
  log racing with inode writeback to write inodes with incorrect link
  count to disk; file data mapping corruptions as a result of incorrect
  lock cycling when attaching dquots; refcount metadata corruption if
  one actually manages to share a block 2^32 times; and the log
  clobbering cow staging extents if they were formerly metadata blocks.

  Summary:

   - Fix a race condition w.r.t. percpu inode free counters

   - Fix a broken error return in xfs_remove

   - Print FS UUID at mount/unmount time

   - Numerous fixes to the online fsck code

   - Fix inode locking inconsistency problems when dealing with realtime
     metadata files

   - Actually merge pull requests so that we capture the cover letter
     contents

   - Fix a race between rebuilding VFS inode state and the AIL flushing
     inodes that could cause corrupt inodes to be written to the
     filesystem

   - Fix a data corruption problem resulting from a write() to an
     unwritten extent racing with writeback started on behalf of memory
     reclaim changing the extent state

   - Add debugging knobs so that we can test iomap invalidation

   - Fix the blockdev pagecache contents being stale after unmounting
     the filesystem, leading to spurious xfs_db errors and corrupt
     metadumps

   - Fix a file mapping corruption bug due to ilock cycling when
     attaching dquots to a file during delalloc reservation

   - Fix a refcount btree corruption problem due to the refcount
     adjustment code not handling MAXREFCOUNT correctly, resulting in
     unnecessary record splits

   - Fix COW staging extent alloctions not being classified as USERDATA,
     which results in filestreams being ignored and possible data
     corruption if the allocation was filled from the AGFL and the block
     buffer is still being tracked in the AIL

   - Fix new duplicated includes

   - Fix a race between the dquot shrinker and dquot freeing that could
     cause a UAF"

* tag 'xfs-6.2-merge-8' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (50 commits)
  xfs: dquot shrinker doesn't check for XFS_DQFLAG_FREEING
  xfs: Remove duplicated include in xfs_iomap.c
  xfs: invalidate xfs_bufs when allocating cow extents
  xfs: get rid of assert from xfs_btree_islastblock
  xfs: estimate post-merge refcounts correctly
  xfs: hoist refcount record merge predicates
  xfs: fix super block buf log item UAF during force shutdown
  xfs: wait iclog complete before tearing down AIL
  xfs: attach dquots to inode before reading data/cow fork mappings
  xfs: shut up -Wuninitialized in xfsaild_push
  xfs: use memcpy, not strncpy, to format the attr prefix during listxattr
  xfs: invalidate block device page cache during unmount
  xfs: add debug knob to slow down write for fun
  xfs: add debug knob to slow down writeback for fun
  xfs: drop write error injection is unfixable, remove it
  xfs: use iomap_valid method to detect stale cached iomaps
  iomap: write iomap validity checks
  xfs: xfs_bmap_punch_delalloc_range() should take a byte range
  iomap: buffered write failure should not truncate the page cache
  xfs,iomap: move delalloc punching to iomap
  ...
2022-12-14 10:11:51 -08:00
Linus Torvalds
e2ca6ba6ba MM patches for 6.2-rc1.
- More userfaultfs work from Peter Xu.
 
 - Several convert-to-folios series from Sidhartha Kumar and Huang Ying.
 
 - Some filemap cleanups from Vishal Moola.
 
 - David Hildenbrand added the ability to selftest anon memory COW handling.
 
 - Some cpuset simplifications from Liu Shixin.
 
 - Addition of vmalloc tracing support by Uladzislau Rezki.
 
 - Some pagecache folioifications and simplifications from Matthew Wilcox.
 
 - A pagemap cleanup from Kefeng Wang: we have VM_ACCESS_FLAGS, so use it.
 
 - Miguel Ojeda contributed some cleanups for our use of the
   __no_sanitize_thread__ gcc keyword.  This series shold have been in the
   non-MM tree, my bad.
 
 - Naoya Horiguchi improved the interaction between memory poisoning and
   memory section removal for huge pages.
 
 - DAMON cleanups and tuneups from SeongJae Park
 
 - Tony Luck fixed the handling of COW faults against poisoned pages.
 
 - Peter Xu utilized the PTE marker code for handling swapin errors.
 
 - Hugh Dickins reworked compound page mapcount handling, simplifying it
   and making it more efficient.
 
 - Removal of the autonuma savedwrite infrastructure from Nadav Amit and
   David Hildenbrand.
 
 - zram support for multiple compression streams from Sergey Senozhatsky.
 
 - David Hildenbrand reworked the GUP code's R/O long-term pinning so
   that drivers no longer need to use the FOLL_FORCE workaround which
   didn't work very well anyway.
 
 - Mel Gorman altered the page allocator so that local IRQs can remnain
   enabled during per-cpu page allocations.
 
 - Vishal Moola removed the try_to_release_page() wrapper.
 
 - Stefan Roesch added some per-BDI sysfs tunables which are used to
   prevent network block devices from dirtying excessive amounts of
   pagecache.
 
 - David Hildenbrand did some cleanup and repair work on KSM COW
   breaking.
 
 - Nhat Pham and Johannes Weiner have implemented writeback in zswap's
   zsmalloc backend.
 
 - Brian Foster has fixed a longstanding corner-case oddity in
   file[map]_write_and_wait_range().
 
 - sparse-vmemmap changes for MIPS, LoongArch and NIOS2 from Feiyang
   Chen.
 
 - Shiyang Ruan has done some work on fsdax, to make its reflink mode
   work better under xfstests.  Better, but still not perfect.
 
 - Christoph Hellwig has removed the .writepage() method from several
   filesystems.  They only need .writepages().
 
 - Yosry Ahmed wrote a series which fixes the memcg reclaim target
   beancounting.
 
 - David Hildenbrand has fixed some of our MM selftests for 32-bit
   machines.
 
 - Many singleton patches, as usual.
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Merge tag 'mm-stable-2022-12-13' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - More userfaultfs work from Peter Xu

 - Several convert-to-folios series from Sidhartha Kumar and Huang Ying

 - Some filemap cleanups from Vishal Moola

 - David Hildenbrand added the ability to selftest anon memory COW
   handling

 - Some cpuset simplifications from Liu Shixin

 - Addition of vmalloc tracing support by Uladzislau Rezki

 - Some pagecache folioifications and simplifications from Matthew
   Wilcox

 - A pagemap cleanup from Kefeng Wang: we have VM_ACCESS_FLAGS, so use
   it

 - Miguel Ojeda contributed some cleanups for our use of the
   __no_sanitize_thread__ gcc keyword.

   This series should have been in the non-MM tree, my bad

 - Naoya Horiguchi improved the interaction between memory poisoning and
   memory section removal for huge pages

 - DAMON cleanups and tuneups from SeongJae Park

 - Tony Luck fixed the handling of COW faults against poisoned pages

 - Peter Xu utilized the PTE marker code for handling swapin errors

 - Hugh Dickins reworked compound page mapcount handling, simplifying it
   and making it more efficient

 - Removal of the autonuma savedwrite infrastructure from Nadav Amit and
   David Hildenbrand

 - zram support for multiple compression streams from Sergey Senozhatsky

 - David Hildenbrand reworked the GUP code's R/O long-term pinning so
   that drivers no longer need to use the FOLL_FORCE workaround which
   didn't work very well anyway

 - Mel Gorman altered the page allocator so that local IRQs can remnain
   enabled during per-cpu page allocations

 - Vishal Moola removed the try_to_release_page() wrapper

 - Stefan Roesch added some per-BDI sysfs tunables which are used to
   prevent network block devices from dirtying excessive amounts of
   pagecache

 - David Hildenbrand did some cleanup and repair work on KSM COW
   breaking

 - Nhat Pham and Johannes Weiner have implemented writeback in zswap's
   zsmalloc backend

 - Brian Foster has fixed a longstanding corner-case oddity in
   file[map]_write_and_wait_range()

 - sparse-vmemmap changes for MIPS, LoongArch and NIOS2 from Feiyang
   Chen

 - Shiyang Ruan has done some work on fsdax, to make its reflink mode
   work better under xfstests. Better, but still not perfect

 - Christoph Hellwig has removed the .writepage() method from several
   filesystems. They only need .writepages()

 - Yosry Ahmed wrote a series which fixes the memcg reclaim target
   beancounting

 - David Hildenbrand has fixed some of our MM selftests for 32-bit
   machines

 - Many singleton patches, as usual

* tag 'mm-stable-2022-12-13' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (313 commits)
  mm/hugetlb: set head flag before setting compound_order in __prep_compound_gigantic_folio
  mm: mmu_gather: allow more than one batch of delayed rmaps
  mm: fix typo in struct pglist_data code comment
  kmsan: fix memcpy tests
  mm: add cond_resched() in swapin_walk_pmd_entry()
  mm: do not show fs mm pc for VM_LOCKONFAULT pages
  selftests/vm: ksm_functional_tests: fixes for 32bit
  selftests/vm: cow: fix compile warning on 32bit
  selftests/vm: madv_populate: fix missing MADV_POPULATE_(READ|WRITE) definitions
  mm/gup_test: fix PIN_LONGTERM_TEST_READ with highmem
  mm,thp,rmap: fix races between updates of subpages_mapcount
  mm: memcg: fix swapcached stat accounting
  mm: add nodes= arg to memory.reclaim
  mm: disable top-tier fallback to reclaim on proactive reclaim
  selftests: cgroup: make sure reclaim target memcg is unprotected
  selftests: cgroup: refactor proactive reclaim code to reclaim_until()
  mm: memcg: fix stale protection of reclaim target memcg
  mm/mmap: properly unaccount memory on mas_preallocate() failure
  omfs: remove ->writepage
  jfs: remove ->writepage
  ...
2022-12-13 19:29:45 -08:00
Linus Torvalds
6a518afcc2 fs.acl.rework.v6.2
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Merge tag 'fs.acl.rework.v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping

Pull VFS acl updates from Christian Brauner:
 "This contains the work that builds a dedicated vfs posix acl api.

  The origins of this work trace back to v5.19 but it took quite a while
  to understand the various filesystem specific implementations in
  sufficient detail and also come up with an acceptable solution.

  As we discussed and seen multiple times the current state of how posix
  acls are handled isn't nice and comes with a lot of problems: The
  current way of handling posix acls via the generic xattr api is error
  prone, hard to maintain, and type unsafe for the vfs until we call
  into the filesystem's dedicated get and set inode operations.

  It is already the case that posix acls are special-cased to death all
  the way through the vfs. There are an uncounted number of hacks that
  operate on the uapi posix acl struct instead of the dedicated vfs
  struct posix_acl. And the vfs must be involved in order to interpret
  and fixup posix acls before storing them to the backing store, caching
  them, reporting them to userspace, or for permission checking.

  Currently a range of hacks and duct tape exist to make this work. As
  with most things this is really no ones fault it's just something that
  happened over time. But the code is hard to understand and difficult
  to maintain and one is constantly at risk of introducing bugs and
  regressions when having to touch it.

  Instead of continuing to hack posix acls through the xattr handlers
  this series builds a dedicated posix acl api solely around the get and
  set inode operations.

  Going forward, the vfs_get_acl(), vfs_remove_acl(), and vfs_set_acl()
  helpers must be used in order to interact with posix acls. They
  operate directly on the vfs internal struct posix_acl instead of
  abusing the uapi posix acl struct as we currently do. In the end this
  removes all of the hackiness, makes the codepaths easier to maintain,
  and gets us type safety.

  This series passes the LTP and xfstests suites without any
  regressions. For xfstests the following combinations were tested:
   - xfs
   - ext4
   - btrfs
   - overlayfs
   - overlayfs on top of idmapped mounts
   - orangefs
   - (limited) cifs

  There's more simplifications for posix acls that we can make in the
  future if the basic api has made it.

  A few implementation details:

   - The series makes sure to retain exactly the same security and
     integrity module permission checks. Especially for the integrity
     modules this api is a win because right now they convert the uapi
     posix acl struct passed to them via a void pointer into the vfs
     struct posix_acl format to perform permission checking on the mode.

     There's a new dedicated security hook for setting posix acls which
     passes the vfs struct posix_acl not a void pointer. Basing checking
     on the posix acl stored in the uapi format is really unreliable.
     The vfs currently hacks around directly in the uapi struct storing
     values that frankly the security and integrity modules can't
     correctly interpret as evidenced by bugs we reported and fixed in
     this area. It's not necessarily even their fault it's just that the
     format we provide to them is sub optimal.

   - Some filesystems like 9p and cifs need access to the dentry in
     order to get and set posix acls which is why they either only
     partially or not even at all implement get and set inode
     operations. For example, cifs allows setxattr() and getxattr()
     operations but doesn't allow permission checking based on posix
     acls because it can't implement a get acl inode operation.

     Thus, this patch series updates the set acl inode operation to take
     a dentry instead of an inode argument. However, for the get acl
     inode operation we can't do this as the old get acl method is
     called in e.g., generic_permission() and inode_permission(). These
     helpers in turn are called in various filesystem's permission inode
     operation. So passing a dentry argument to the old get acl inode
     operation would amount to passing a dentry to the permission inode
     operation which we shouldn't and probably can't do.

     So instead of extending the existing inode operation Christoph
     suggested to add a new one. He also requested to ensure that the
     get and set acl inode operation taking a dentry are consistently
     named. So for this version the old get acl operation is renamed to
     ->get_inode_acl() and a new ->get_acl() inode operation taking a
     dentry is added. With this we can give both 9p and cifs get and set
     acl inode operations and in turn remove their complex custom posix
     xattr handlers.

     In the future I hope to get rid of the inode method duplication but
     it isn't like we have never had this situation. Readdir is just one
     example. And frankly, the overall gain in type safety and the more
     pleasant api wise are simply too big of a benefit to not accept
     this duplication for a while.

   - We've done a full audit of every codepaths using variant of the
     current generic xattr api to get and set posix acls and
     surprisingly it isn't that many places. There's of course always a
     chance that we might have missed some and if so I'm sure we'll find
     them soon enough.

     The crucial codepaths to be converted are obviously stacking
     filesystems such as ecryptfs and overlayfs.

     For a list of all callers currently using generic xattr api helpers
     see [2] including comments whether they support posix acls or not.

   - The old vfs generic posix acl infrastructure doesn't obey the
     create and replace semantics promised on the setxattr(2) manpage.
     This patch series doesn't address this. It really is something we
     should revisit later though.

  The patches are roughly organized as follows:

   (1) Change existing set acl inode operation to take a dentry
       argument (Intended to be a non-functional change)

   (2) Rename existing get acl method (Intended to be a non-functional
       change)

   (3) Implement get and set acl inode operations for filesystems that
       couldn't implement one before because of the missing dentry.
       That's mostly 9p and cifs (Intended to be a non-functional
       change)

   (4) Build posix acl api, i.e., add vfs_get_acl(), vfs_remove_acl(),
       and vfs_set_acl() including security and integrity hooks
       (Intended to be a non-functional change)

   (5) Implement get and set acl inode operations for stacking
       filesystems (Intended to be a non-functional change)

   (6) Switch posix acl handling in stacking filesystems to new posix
       acl api now that all filesystems it can stack upon support it.

   (7) Switch vfs to new posix acl api (semantical change)

   (8) Remove all now unused helpers

   (9) Additional regression fixes reported after we merged this into
       linux-next

  Thanks to Seth for a lot of good discussion around this and
  encouragement and input from Christoph"

* tag 'fs.acl.rework.v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping: (36 commits)
  posix_acl: Fix the type of sentinel in get_acl
  orangefs: fix mode handling
  ovl: call posix_acl_release() after error checking
  evm: remove dead code in evm_inode_set_acl()
  cifs: check whether acl is valid early
  acl: make vfs_posix_acl_to_xattr() static
  acl: remove a slew of now unused helpers
  9p: use stub posix acl handlers
  cifs: use stub posix acl handlers
  ovl: use stub posix acl handlers
  ecryptfs: use stub posix acl handlers
  evm: remove evm_xattr_acl_change()
  xattr: use posix acl api
  ovl: use posix acl api
  ovl: implement set acl method
  ovl: implement get acl method
  ecryptfs: implement set acl method
  ecryptfs: implement get acl method
  ksmbd: use vfs_remove_acl()
  acl: add vfs_remove_acl()
  ...
2022-12-12 18:46:39 -08:00
Shiyang Ruan
480017957d xfs: remove restrictions for fsdax and reflink
Since the basic function for fsdax and reflink has been implemented,
remove the restrictions of them for widly test.

Link: https://lkml.kernel.org/r/1669908773-207-1-git-send-email-ruansy.fnst@fujitsu.com
Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-12-11 18:12:17 -08:00
Shiyang Ruan
d984648e42 fsdax,xfs: port unshare to fsdax
Implement unshare in fsdax mode: copy data from srcmap to iomap.

Link: https://lkml.kernel.org/r/1669908753-169-1-git-send-email-ruansy.fnst@fujitsu.com
Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-12-11 18:12:17 -08:00
Shiyang Ruan
64e6edc185 xfs: use dax ops for zero and truncate in fsdax mode
Zero and truncate on a dax file may execute CoW.  So use dax ops which
contains end work for CoW.

Link: https://lkml.kernel.org/r/1669908730-131-1-git-send-email-ruansy.fnst@fujitsu.com
Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-12-11 18:12:16 -08:00
Shiyang Ruan
c6f0b395b2 fsdax,xfs: set the shared flag when file extent is shared
If a dax page is shared, mapread at different offsets can also trigger
page fault on same dax page.  So, change the flag from "cow" to "shared". 
And get the shared flag from filesystem when read.

Link: https://lkml.kernel.org/r/1669908538-55-5-git-send-email-ruansy.fnst@fujitsu.com
Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-12-11 18:12:16 -08:00
Dave Chinner
52f31ed228 xfs: dquot shrinker doesn't check for XFS_DQFLAG_FREEING
Resulting in a UAF if the shrinker races with some other dquot
freeing mechanism that sets XFS_DQFLAG_FREEING before the dquot is
removed from the LRU. This can occur if a dquot purge races with
drop_caches.

Reported-by: syzbot+912776840162c13db1a3@syzkaller.appspotmail.com
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>
2022-12-08 08:29:58 -08:00
Yang Li
1f5619ed88 xfs: Remove duplicated include in xfs_iomap.c
./fs/xfs/xfs_iomap.c: xfs_error.h is included more than once.
./fs/xfs/xfs_iomap.c: xfs_errortag.h is included more than once.

Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=3337
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2022-12-04 09:42:59 -08:00
Darrick J. Wong
ddfdd530e4 xfs: invalidate xfs_bufs when allocating cow extents
While investigating test failures in xfs/17[1-3] in alwayscow mode, I
noticed through code inspection that xfs_bmap_alloc_userdata isn't
setting XFS_ALLOC_USERDATA when allocating extents for a file's CoW
fork.  COW staging extents should be flagged as USERDATA, since user
data are persisted to these blocks before being remapped into a file.

This mis-classification has a few impacts on the behavior of the system.
First, the filestreams allocator is supposed to keep allocating from a
chosen AG until it runs out of space in that AG.  However, it only does
that for USERDATA allocations, which means that COW allocations aren't
tied to the filestreams AG.  Fortunately, few people use filestreams, so
nobody's noticed.

A more serious problem is that xfs_alloc_ag_vextent_small looks for a
buffer to invalidate *if* the USERDATA flag is set and the AG is so full
that the allocation had to come from the AGFL because the cntbt is
empty.  The consequences of not invalidating the buffer are severe --
if the AIL incorrectly checkpoints a buffer that is now being used to
store user data, that action will clobber the user's written data.

Fix filestreams and yet another data corruption vector by flagging COW
allocations as USERDATA.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-12-01 09:36:16 -08:00
Guo Xuenan
8c25febf23 xfs: get rid of assert from xfs_btree_islastblock
xfs_btree_check_block contains debugging knobs. With XFS_DEBUG setting up,
turn on the debugging knob can trigger the assert of xfs_btree_islastblock,
test script as follows:

while true
do
    mount $disk $mountpoint
    fsstress -d $testdir -l 0 -n 10000 -p 4 >/dev/null
    echo 1 > /sys/fs/xfs/sda/errortag/btree_chk_sblk
    sleep 10
    umount $mountpoint
done

Kick off fsstress and only *then* turn on the debugging knob. If it
happens that the knob gets turned on after the cntbt lookup succeeds
but before the call to xfs_btree_islastblock, then we *can* end up in
the situation where a previously checked btree block suddenly starts
returning EFSCORRUPTED from xfs_btree_check_block. Kaboom.

Darrick give a very detailed explanation as follows:
Looking back at commit 27d9ee577d, I think the point of all this was
to make sure that the cursor has actually performed a lookup, and that
the btree block at whatever level we're asking about is ok.

If the caller hasn't ever done a lookup, the bc_levels array will be
empty, so cur->bc_levels[level].bp pointer will be NULL.  The call to
xfs_btree_get_block will crash anyway, so the "ASSERT(block);" part is
pointless.

If the caller did a lookup but the lookup failed due to block
corruption, the corresponding cur->bc_levels[level].bp pointer will also
be NULL, and we'll still crash.  The "ASSERT(xfs_btree_check_block);"
logic is also unnecessary.

If the cursor level points to an inode root, the block buffer will be
incore, so it had better always be consistent.

If the caller ignores a failed lookup after a successful one and calls
this function, the cursor state is garbage and the assert wouldn't have
tripped anyway. So get rid of the assert.

Fixes: 27d9ee577d ("xfs: actually check xfs_btree_check_block return in xfs_btree_islastblock")
Signed-off-by: Guo Xuenan <guoxuenan@huawei.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2022-12-01 09:36:16 -08:00
Darrick J. Wong
948961964b xfs: fix broken MAXREFCOUNT handling
This series fixes a bug in the refcount code where we don't merge
 records correctly if the refcount is hovering around MAXREFCOUNT.  This
 fixes regressions in xfs/179 when fsdax is enabled.  xfs/179 itself will
 be modified to exploit the bug through the pagecache path.
 
 Signed-off-by: Darrick J. Wong <djwong@kernel.org>
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Merge tag 'maxrefcount-fixes-6.2_2022-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.2-mergeD

xfs: fix broken MAXREFCOUNT handling

This series fixes a bug in the refcount code where we don't merge
records correctly if the refcount is hovering around MAXREFCOUNT.  This
fixes regressions in xfs/179 when fsdax is enabled.  xfs/179 itself will
be modified to exploit the bug through the pagecache path.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>

* tag 'maxrefcount-fixes-6.2_2022-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux:
  xfs: estimate post-merge refcounts correctly
  xfs: hoist refcount record merge predicates
2022-12-01 09:35:52 -08:00
Darrick J. Wong
b25d1984aa xfs: estimate post-merge refcounts correctly
Upon enabling fsdax + reflink for XFS, xfs/179 began to report refcount
metadata corruptions after being run.  Specifically, xfs_repair noticed
single-block refcount records that could be combined but had not been.

The root cause of this is improper MAXREFCOUNT edge case handling in
xfs_refcount_merge_extents.  When we're trying to find candidates for a
refcount btree record merge, we compute the refcount attribute of the
merged record, but we fail to account for the fact that once a record
hits rc_refcount == MAXREFCOUNT, it is pinned that way forever.  Hence
the computed refcount is wrong, and we fail to merge the extents.

Fix this by adjusting the merge predicates to compute the adjusted
refcount correctly.

Fixes: 3172725814 ("xfs: adjust refcount of an extent of blocks in refcount btree")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Xiao Yang <yangx.jy@fujitsu.com>
2022-12-01 09:32:04 -08:00
Darrick J. Wong
9d720a5a65 xfs: hoist refcount record merge predicates
Hoist these multiline conditionals into separate static inline helpers
to improve readability and set the stage for corruption fixes that will
be introduced in the next patch.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Xiao Yang <yangx.jy@fujitsu.com>
2022-12-01 09:32:04 -08:00
Guo Xuenan
575689fc0f xfs: fix super block buf log item UAF during force shutdown
xfs log io error will trigger xlog shut down, and end_io worker call
xlog_state_shutdown_callbacks to unpin and release the buf log item.
The race condition is that when there are some thread doing transaction
commit and happened not to be intercepted by xlog_is_shutdown, then,
these log item will be insert into CIL, when unpin and release these
buf log item, UAF will occur. BTW, add delay before `xlog_cil_commit`
can increase recurrence probability.

The following call graph actually encountered this bad situation.
fsstress                    io end worker kworker/0:1H-216
                            xlog_ioend_work
                              ->xlog_force_shutdown
                                ->xlog_state_shutdown_callbacks
                                  ->xlog_cil_process_committed
                                    ->xlog_cil_committed
                                      ->xfs_trans_committed_bulk
->xfs_trans_apply_sb_deltas             ->li_ops->iop_unpin(lip, 1);
  ->xfs_trans_getsb
    ->_xfs_trans_bjoin
      ->xfs_buf_item_init
        ->if (bip) { return 0;} //relog
->xlog_cil_commit
  ->xlog_cil_insert_items //insert into CIL
                                           ->xfs_buf_ioend_fail(bp);
                                             ->xfs_buf_ioend
                                               ->xfs_buf_item_done
                                                 ->xfs_buf_item_relse
                                                   ->xfs_buf_item_free

when cil push worker gather percpu cil and insert super block buf log item
into ctx->log_items then uaf occurs.

==================================================================
BUG: KASAN: use-after-free in xlog_cil_push_work+0x1c8f/0x22f0
Write of size 8 at addr ffff88801800f3f0 by task kworker/u4:4/105

CPU: 0 PID: 105 Comm: kworker/u4:4 Tainted: G W
6.1.0-rc1-00001-g274115149b42 #136
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.13.0-1ubuntu1.1 04/01/2014
Workqueue: xfs-cil/sda xlog_cil_push_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x4d/0x66
 print_report+0x171/0x4a6
 kasan_report+0xb3/0x130
 xlog_cil_push_work+0x1c8f/0x22f0
 process_one_work+0x6f9/0xf70
 worker_thread+0x578/0xf30
 kthread+0x28c/0x330
 ret_from_fork+0x1f/0x30
 </TASK>

Allocated by task 2145:
 kasan_save_stack+0x1e/0x40
 kasan_set_track+0x21/0x30
 __kasan_slab_alloc+0x54/0x60
 kmem_cache_alloc+0x14a/0x510
 xfs_buf_item_init+0x160/0x6d0
 _xfs_trans_bjoin+0x7f/0x2e0
 xfs_trans_getsb+0xb6/0x3f0
 xfs_trans_apply_sb_deltas+0x1f/0x8c0
 __xfs_trans_commit+0xa25/0xe10
 xfs_symlink+0xe23/0x1660
 xfs_vn_symlink+0x157/0x280
 vfs_symlink+0x491/0x790
 do_symlinkat+0x128/0x220
 __x64_sys_symlink+0x7a/0x90
 do_syscall_64+0x35/0x80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 216:
 kasan_save_stack+0x1e/0x40
 kasan_set_track+0x21/0x30
 kasan_save_free_info+0x2a/0x40
 __kasan_slab_free+0x105/0x1a0
 kmem_cache_free+0xb6/0x460
 xfs_buf_ioend+0x1e9/0x11f0
 xfs_buf_item_unpin+0x3d6/0x840
 xfs_trans_committed_bulk+0x4c2/0x7c0
 xlog_cil_committed+0xab6/0xfb0
 xlog_cil_process_committed+0x117/0x1e0
 xlog_state_shutdown_callbacks+0x208/0x440
 xlog_force_shutdown+0x1b3/0x3a0
 xlog_ioend_work+0xef/0x1d0
 process_one_work+0x6f9/0xf70
 worker_thread+0x578/0xf30
 kthread+0x28c/0x330
 ret_from_fork+0x1f/0x30

The buggy address belongs to the object at ffff88801800f388
 which belongs to the cache xfs_buf_item of size 272
The buggy address is located 104 bytes inside of
 272-byte region [ffff88801800f388, ffff88801800f498)

The buggy address belongs to the physical page:
page:ffffea0000600380 refcount:1 mapcount:0 mapping:0000000000000000
index:0xffff88801800f208 pfn:0x1800e
head:ffffea0000600380 order:1 compound_mapcount:0 compound_pincount:0
flags: 0x1fffff80010200(slab|head|node=0|zone=1|lastcpupid=0x1fffff)
raw: 001fffff80010200 ffffea0000699788 ffff88801319db50 ffff88800fb50640
raw: ffff88801800f208 000000000015000a 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88801800f280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801800f300: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88801800f380: fc fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                             ^
 ffff88801800f400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801800f480: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
Disabling lock debugging due to kernel taint

Signed-off-by: Guo Xuenan <guoxuenan@huawei.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2022-11-30 09:25:46 -08:00
Guo Xuenan
1eb52a6a71 xfs: wait iclog complete before tearing down AIL
Fix uaf in xfs_trans_ail_delete during xlog force shutdown.
In commit cd6f79d1fb ("xfs: run callbacks before waking waiters in
xlog_state_shutdown_callbacks") changed the order of running callbacks
and wait for iclog completion to avoid unmount path untimely destroy AIL.
But which seems not enough to ensue this, adding mdelay in
`xfs_buf_item_unpin` can prove that.

The reproduction is as follows. To ensure destroy AIL safely,
we should wait all xlog ioend workers done and sync the AIL.

==================================================================
BUG: KASAN: use-after-free in xfs_trans_ail_delete+0x240/0x2a0
Read of size 8 at addr ffff888023169400 by task kworker/1:1H/43

CPU: 1 PID: 43 Comm: kworker/1:1H Tainted: G        W
6.1.0-rc1-00002-gc28266863c4a #137
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.13.0-1ubuntu1.1 04/01/2014
Workqueue: xfs-log/sda xlog_ioend_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x4d/0x66
 print_report+0x171/0x4a6
 kasan_report+0xb3/0x130
 xfs_trans_ail_delete+0x240/0x2a0
 xfs_buf_item_done+0x7b/0xa0
 xfs_buf_ioend+0x1e9/0x11f0
 xfs_buf_item_unpin+0x4c8/0x860
 xfs_trans_committed_bulk+0x4c2/0x7c0
 xlog_cil_committed+0xab6/0xfb0
 xlog_cil_process_committed+0x117/0x1e0
 xlog_state_shutdown_callbacks+0x208/0x440
 xlog_force_shutdown+0x1b3/0x3a0
 xlog_ioend_work+0xef/0x1d0
 process_one_work+0x6f9/0xf70
 worker_thread+0x578/0xf30
 kthread+0x28c/0x330
 ret_from_fork+0x1f/0x30
 </TASK>

Allocated by task 9606:
 kasan_save_stack+0x1e/0x40
 kasan_set_track+0x21/0x30
 __kasan_kmalloc+0x7a/0x90
 __kmalloc+0x59/0x140
 kmem_alloc+0xb2/0x2f0
 xfs_trans_ail_init+0x20/0x320
 xfs_log_mount+0x37e/0x690
 xfs_mountfs+0xe36/0x1b40
 xfs_fs_fill_super+0xc5c/0x1a70
 get_tree_bdev+0x3c5/0x6c0
 vfs_get_tree+0x85/0x250
 path_mount+0xec3/0x1830
 do_mount+0xef/0x110
 __x64_sys_mount+0x150/0x1f0
 do_syscall_64+0x35/0x80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 9662:
 kasan_save_stack+0x1e/0x40
 kasan_set_track+0x21/0x30
 kasan_save_free_info+0x2a/0x40
 __kasan_slab_free+0x105/0x1a0
 __kmem_cache_free+0x99/0x2d0
 kvfree+0x3a/0x40
 xfs_log_unmount+0x60/0xf0
 xfs_unmountfs+0xf3/0x1d0
 xfs_fs_put_super+0x78/0x300
 generic_shutdown_super+0x151/0x400
 kill_block_super+0x9a/0xe0
 deactivate_locked_super+0x82/0xe0
 deactivate_super+0x91/0xb0
 cleanup_mnt+0x32a/0x4a0
 task_work_run+0x15f/0x240
 exit_to_user_mode_prepare+0x188/0x190
 syscall_exit_to_user_mode+0x12/0x30
 do_syscall_64+0x42/0x80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff888023169400
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 0 bytes inside of
 128-byte region [ffff888023169400, ffff888023169480)

The buggy address belongs to the physical page:
page:ffffea00008c5a00 refcount:1 mapcount:0 mapping:0000000000000000
index:0xffff888023168f80 pfn:0x23168
head:ffffea00008c5a00 order:1 compound_mapcount:0 compound_pincount:0
flags: 0x1fffff80010200(slab|head|node=0|zone=1|lastcpupid=0x1fffff)
raw: 001fffff80010200 ffffea00006b3988 ffffea0000577a88 ffff88800f842ac0
raw: ffff888023168f80 0000000000150007 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888023169300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888023169380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888023169400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff888023169480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888023169500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
Disabling lock debugging due to kernel taint

Fixes: cd6f79d1fb ("xfs: run callbacks before waking waiters in xlog_state_shutdown_callbacks")
Signed-off-by: Guo Xuenan <guoxuenan@huawei.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2022-11-30 09:25:46 -08:00
Darrick J. Wong
4c6dbfd275 xfs: attach dquots to inode before reading data/cow fork mappings
I've been running near-continuous integration testing of online fsck,
and I've noticed that once a day, one of the ARM VMs will fail the test
with out of order records in the data fork.

xfs/804 races fsstress with online scrub (aka scan but do not change
anything), so I think this might be a bug in the core xfs code.  This
also only seems to trigger if one runs the test for more than ~6 minutes
via TIME_FACTOR=13 or something.
https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfstests-dev.git/tree/tests/xfs/804?h=djwong-wtf

I added a debugging patch to the kernel to check the data fork extents
after taking the ILOCK, before dropping ILOCK, and before and after each
bmapping operation.  So far I've narrowed it down to the delalloc code
inserting a record in the wrong place in the iext tree:

xfs_bmap_add_extent_hole_delay, near line 2691:

	case 0:
		/*
		 * New allocation is not contiguous with another
		 * delayed allocation.
		 * Insert a new entry.
		 */
		oldlen = newlen = 0;
		xfs_iunlock_check_datafork(ip);		<-- ok here
		xfs_iext_insert(ip, icur, new, state);
		xfs_iunlock_check_datafork(ip);		<-- bad here
		break;
	}

I recorded the state of the data fork mappings and iext cursor state
when a corrupt data fork is detected immediately after the
xfs_bmap_add_extent_hole_delay call in xfs_bmapi_reserve_delalloc:

ino 0x140bb3 func xfs_bmapi_reserve_delalloc line 4164 data fork:
    ino 0x140bb3 nr 0x0 nr_real 0x0 offset 0xb9 blockcount 0x1f startblock 0x935de2 state 1
    ino 0x140bb3 nr 0x1 nr_real 0x1 offset 0xe6 blockcount 0xa startblock 0xffffffffe0007 state 0
    ino 0x140bb3 nr 0x2 nr_real 0x1 offset 0xd8 blockcount 0xe startblock 0x935e01 state 0

Here we see that a delalloc extent was inserted into the wrong position
in the iext leaf, same as all the other times.  The extra trace data I
collected are as follows:

ino 0x140bb3 fork 0 oldoff 0xe6 oldlen 0x4 oldprealloc 0x6 isize 0xe6000
    ino 0x140bb3 oldgotoff 0xea oldgotstart 0xfffffffffffffffe oldgotcount 0x0 oldgotstate 0
    ino 0x140bb3 crapgotoff 0x0 crapgotstart 0x0 crapgotcount 0x0 crapgotstate 0
    ino 0x140bb3 freshgotoff 0xd8 freshgotstart 0x935e01 freshgotcount 0xe freshgotstate 0
    ino 0x140bb3 nowgotoff 0xe6 nowgotstart 0xffffffffe0007 nowgotcount 0xa nowgotstate 0
    ino 0x140bb3 oldicurpos 1 oldleafnr 2 oldleaf 0xfffffc00f0609a00
    ino 0x140bb3 crapicurpos 2 crapleafnr 2 crapleaf 0xfffffc00f0609a00
    ino 0x140bb3 freshicurpos 1 freshleafnr 2 freshleaf 0xfffffc00f0609a00
    ino 0x140bb3 newicurpos 1 newleafnr 3 newleaf 0xfffffc00f0609a00

The first line shows that xfs_bmapi_reserve_delalloc was called with
whichfork=XFS_DATA_FORK, off=0xe6, len=0x4, prealloc=6.

The second line ("oldgot") shows the contents of @got at the beginning
of the call, which are the results of the first iext lookup in
xfs_buffered_write_iomap_begin.

Line 3 ("crapgot") is the result of duplicating the cursor at the start
of the body of xfs_bmapi_reserve_delalloc and performing a fresh lookup
at @off.

Line 4 ("freshgot") is the result of a new xfs_iext_get_extent right
before the call to xfs_bmap_add_extent_hole_delay.  Totally garbage.

Line 5 ("nowgot") is contents of @got after the
xfs_bmap_add_extent_hole_delay call.

Line 6 is the contents of @icur at the beginning fo the call.  Lines 7-9
are the contents of the iext cursors at the point where the block
mappings were sampled.

I think @oldgot is a HOLESTARTBLOCK extent because the first lookup
didn't find anything, so we filled in imap with "fake hole until the
end".  At the time of the first lookup, I suspect that there's only one
32-block unwritten extent in the mapping (hence oldicurpos==1) but by
the time we get to recording crapgot, crapicurpos==2.

Dave then added:

Ok, that's much simpler to reason about, and implies the smoke is
coming from xfs_buffered_write_iomap_begin() or
xfs_bmapi_reserve_delalloc(). I suspect the former - it does a lot
of stuff with the ILOCK_EXCL held.....

.... including calling xfs_qm_dqattach_locked().

xfs_buffered_write_iomap_begin
  ILOCK_EXCL
  look up icur
  xfs_qm_dqattach_locked
    xfs_qm_dqattach_one
      xfs_qm_dqget_inode
        dquot cache miss
        xfs_iunlock(ip, XFS_ILOCK_EXCL);
        error = xfs_qm_dqread(mp, id, type, can_alloc, &dqp);
        xfs_ilock(ip, XFS_ILOCK_EXCL);
  ....
  xfs_bmapi_reserve_delalloc(icur)

Yup, that's what is letting the magic smoke out -
xfs_qm_dqattach_locked() can cycle the ILOCK. If that happens, we
can pass a stale icur to xfs_bmapi_reserve_delalloc() and it all
goes downhill from there.

Back to Darrick now:

So.  Fix this by moving the dqattach_locked call up before we take the
ILOCK, like all the other callers in that file.

Fixes: a526c85c22 ("xfs: move xfs_file_iomap_begin_delay around") # goes further back than this
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-11-30 08:55:18 -08:00
Darrick J. Wong
e5827a007a xfs: shut up -Wuninitialized in xfsaild_push
-Wuninitialized complains about @target in xfsaild_push being
uninitialized in the case where the waitqueue is active but there is no
last item in the AIL to wait for.  I /think/ it should never be the case
that the subsequent xfs_trans_ail_cursor_first returns a log item and
hence we'll never end up at XFS_LSN_CMP, but let's make this explicit.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-11-30 08:55:18 -08:00
Darrick J. Wong
fd5beaff25 xfs: use memcpy, not strncpy, to format the attr prefix during listxattr
When -Wstringop-truncation is enabled, the compiler complains about
truncation of the null byte at the end of the xattr name prefix.  This
is intentional, since we're concatenating the two strings together and
do _not_ want a null byte in the middle of the name.

We've already ensured that the name buffer is long enough to handle
prefix and name, and the prefix_len is supposed to be the length of the
prefix string without the null byte, so use memcpy here instead.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-11-30 08:55:18 -08:00
Darrick J. Wong
032e160305 xfs: invalidate block device page cache during unmount
Every now and then I see fstests failures on aarch64 (64k pages) that
trigger on the following sequence:

mkfs.xfs $dev
mount $dev $mnt
touch $mnt/a
umount $mnt
xfs_db -c 'path /a' -c 'print' $dev

99% of the time this succeeds, but every now and then xfs_db cannot find
/a and fails.  This turns out to be a race involving udev/blkid, the
page cache for the block device, and the xfs_db process.

udev is triggered whenever anyone closes a block device or unmounts it.
The default udev rules invoke blkid to read the fs super and create
symlinks to the bdev under /dev/disk.  For this, it uses buffered reads
through the page cache.

xfs_db also uses buffered reads to examine metadata.  There is no
coordination between xfs_db and udev, which means that they can run
concurrently.  Note there is no coordination between the kernel and
blkid either.

On a system with 64k pages, the page cache can cache the superblock and
the root inode (and hence the root dir) with the same 64k page.  If
udev spawns blkid after the mkfs and the system is busy enough that it
is still running when xfs_db starts up, they'll both read from the same
page in the pagecache.

The unmount writes updated inode metadata to disk directly.  The XFS
buffer cache does not use the bdev pagecache, nor does it invalidate the
pagecache on umount.  If the above scenario occurs, the pagecache no
longer reflects what's on disk, xfs_db reads the stale metadata, and
fails to find /a.  Most of the time this succeeds because closing a bdev
invalidates the page cache, but when processes race, everyone loses.

Fix the problem by invalidating the bdev pagecache after flushing the
bdev, so that xfs_db will see up to date metadata.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-11-30 08:55:18 -08:00
Darrick J. Wong
254e345928 xfs: add debug knob to slow down write for fun
Add a new error injection knob so that we can arbitrarily slow down
pagecache writes to test for race conditions and aberrant reclaim
behavior if the writeback mechanisms are slow to issue writeback.  This
will enable functional testing for the ifork sequence counters
introduced in commit 304a68b9c6 ("xfs: use iomap_valid method to
detect stale cached iomaps") that fixes write racing with reclaim
writeback.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-11-28 17:54:49 -08:00
Darrick J. Wong
c2beff99eb xfs: add debug knob to slow down writeback for fun
Add a new error injection knob so that we can arbitrarily slow down
writeback to test for race conditions and aberrant reclaim behavior if
the writeback mechanisms are slow to issue writeback.  This will enable
functional testing for the ifork sequence counters introduced in commit
745b3f76d1 ("xfs: maintain a sequence count for inode fork
manipulations").

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-11-28 17:24:35 -08:00
Darrick J. Wong
7dd73802f9 xfs, iomap: fix data corruption due to stale cached iomaps
This patch series fixes a data corruption that occurs in a specific
 multi-threaded write workload. The workload combined
 racing unaligned adjacent buffered writes with low memory conditions
 that caused both writeback and memory reclaim to race with the
 writes.
 
 The result of this was random partial blocks containing zeroes
 instead of the correct data.  The underlying problem is that iomap
 caches the write iomap for the duration of the write() operation,
 but it fails to take into account that the extent underlying the
 iomap can change whilst the write is in progress.
 
 The short story is that an iomap can span mutliple folios, and so
 under low memory writeback can be cleaning folios the write()
 overlaps. Whilst the overlapping data is cached in memory, this
 isn't a problem, but because the folios are now clean they can be
 reclaimed. Once reclaimed, the write() does the wrong thing when
 re-instantiating partial folios because the iomap no longer reflects
 the underlying state of the extent. e.g. it thinks the extent is
 unwritten, so it zeroes the partial range, when in fact the
 underlying extent is now written and so it should have read the data
 from disk.  This is how we get random zero ranges in the file
 instead of the correct data.
 
 The gory details of the race condition can be found here:
 
 https://lore.kernel.org/linux-xfs/20220817093627.GZ3600936@dread.disaster.area/
 
 Fixing the problem has two aspects. The first aspect of the problem
 is ensuring that iomap can detect a stale cached iomap during a
 write in a race-free manner. We already do this stale iomap
 detection in the writeback path, so we have a mechanism for
 detecting that the iomap backing the data range may have changed
 and needs to be remapped.
 
 In the case of the write() path, we have to ensure that the iomap is
 validated at a point in time when the page cache is stable and
 cannot be reclaimed from under us. We also need to validate the
 extent before we start performing any modifications to the folio
 state or contents. Combine these two requirements together, and the
 only "safe" place to validate the iomap is after we have looked up
 and locked the folio we are going to copy the data into, but before
 we've performed any initialisation operations on that folio.
 
 If the iomap fails validation, we then mark it stale, unlock the
 folio and end the write. This effectively means a stale iomap
 results in a short write. Filesystems should already be able to
 handle this, as write operations can end short for many reasons and
 need to iterate through another mapping cycle to be completed. Hence
 the iomap changes needed to detect and handle stale iomaps during
 write() operations is relatively simple...
 
 However, the assumption is that filesystems should already be able
 to handle write failures safely, and that's where the second
 (first?) part of the problem exists. That is, handling a partial
 write is harder than just "punching out the unused delayed
 allocation extent". This is because mmap() based faults can race
 with writes, and if they land in the delalloc region that the write
 allocated, then punching out the delalloc region can cause data
 corruption.
 
 This data corruption problem is exposed by generic/346 when iomap is
 converted to detect stale iomaps during write() operations. Hence
 write failure in the filesytems needs to handle the fact that the
 write() in progress doesn't necessarily own the data in the page
 cache over the range of the delalloc extent it just allocated.
 
 As a result, we can't just truncate the page cache over the range
 the write() didn't reach and punch all the delalloc extent. We have
 to walk the page cache over the untouched range and skip over any
 dirty data region in the cache in that range. Which is ....
 non-trivial.
 
 That is, iterating the page cache has to handle partially populated
 folios (i.e. block size < page size) that contain data. The data
 might be discontiguous within a folio. Indeed, there might be
 *multiple* discontiguous data regions within a single folio. And to
 make matters more complex, multi-page folios mean we just don't know
 how many sub-folio regions we might have to iterate to find all
 these regions. All the corner cases between the conversions and
 rounding between filesystem block size, folio size and multi-page
 folio size combined with unaligned write offsets kept breaking my
 brain.
 
 However, if we convert the code to track the processed
 write regions by byte ranges instead of fileystem block or page
 cache index, we could simply use mapping_seek_hole_data() to find
 the start and end of each discrete data region within the range we
 needed to scan. SEEK_DATA finds the start of the cached data region,
 SEEK_HOLE finds the end of the region. These are byte based
 interfaces that understand partially uptodate folio regions, and so
 can iterate discrete sub-folio data regions directly. This largely
 solved the problem of discovering the dirty regions we need to keep
 the delalloc extent over.
 
 However, to use mapping_seek_hole_data() without needing to export
 it, we have to move all the delalloc extent cleanup to the iomap
 core and so now the iomap core can clean up delayed allocation
 extents in a safe, sane and filesystem neutral manner.
 
 With all this done, the original data corruption never occurs
 anymore, and we now have a generic mechanism for ensuring that page
 cache writes do not do the wrong thing when writeback and reclaim
 change the state of the physical extent and/or page cache contents
 whilst the write is in progress.
 
 Signed-off-by: Dave Chinner <dchinner@redhat.com>
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Merge tag 'xfs-iomap-stale-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs into xfs-6.2-mergeB

xfs, iomap: fix data corruption due to stale cached iomaps

This patch series fixes a data corruption that occurs in a specific
multi-threaded write workload. The workload combined
racing unaligned adjacent buffered writes with low memory conditions
that caused both writeback and memory reclaim to race with the
writes.

The result of this was random partial blocks containing zeroes
instead of the correct data.  The underlying problem is that iomap
caches the write iomap for the duration of the write() operation,
but it fails to take into account that the extent underlying the
iomap can change whilst the write is in progress.

The short story is that an iomap can span mutliple folios, and so
under low memory writeback can be cleaning folios the write()
overlaps. Whilst the overlapping data is cached in memory, this
isn't a problem, but because the folios are now clean they can be
reclaimed. Once reclaimed, the write() does the wrong thing when
re-instantiating partial folios because the iomap no longer reflects
the underlying state of the extent. e.g. it thinks the extent is
unwritten, so it zeroes the partial range, when in fact the
underlying extent is now written and so it should have read the data
from disk.  This is how we get random zero ranges in the file
instead of the correct data.

The gory details of the race condition can be found here:

https://lore.kernel.org/linux-xfs/20220817093627.GZ3600936@dread.disaster.area/

Fixing the problem has two aspects. The first aspect of the problem
is ensuring that iomap can detect a stale cached iomap during a
write in a race-free manner. We already do this stale iomap
detection in the writeback path, so we have a mechanism for
detecting that the iomap backing the data range may have changed
and needs to be remapped.

In the case of the write() path, we have to ensure that the iomap is
validated at a point in time when the page cache is stable and
cannot be reclaimed from under us. We also need to validate the
extent before we start performing any modifications to the folio
state or contents. Combine these two requirements together, and the
only "safe" place to validate the iomap is after we have looked up
and locked the folio we are going to copy the data into, but before
we've performed any initialisation operations on that folio.

If the iomap fails validation, we then mark it stale, unlock the
folio and end the write. This effectively means a stale iomap
results in a short write. Filesystems should already be able to
handle this, as write operations can end short for many reasons and
need to iterate through another mapping cycle to be completed. Hence
the iomap changes needed to detect and handle stale iomaps during
write() operations is relatively simple...

However, the assumption is that filesystems should already be able
to handle write failures safely, and that's where the second
(first?) part of the problem exists. That is, handling a partial
write is harder than just "punching out the unused delayed
allocation extent". This is because mmap() based faults can race
with writes, and if they land in the delalloc region that the write
allocated, then punching out the delalloc region can cause data
corruption.

This data corruption problem is exposed by generic/346 when iomap is
converted to detect stale iomaps during write() operations. Hence
write failure in the filesytems needs to handle the fact that the
write() in progress doesn't necessarily own the data in the page
cache over the range of the delalloc extent it just allocated.

As a result, we can't just truncate the page cache over the range
the write() didn't reach and punch all the delalloc extent. We have
to walk the page cache over the untouched range and skip over any
dirty data region in the cache in that range. Which is ....
non-trivial.

That is, iterating the page cache has to handle partially populated
folios (i.e. block size < page size) that contain data. The data
might be discontiguous within a folio. Indeed, there might be
*multiple* discontiguous data regions within a single folio. And to
make matters more complex, multi-page folios mean we just don't know
how many sub-folio regions we might have to iterate to find all
these regions. All the corner cases between the conversions and
rounding between filesystem block size, folio size and multi-page
folio size combined with unaligned write offsets kept breaking my
brain.

However, if we convert the code to track the processed
write regions by byte ranges instead of fileystem block or page
cache index, we could simply use mapping_seek_hole_data() to find
the start and end of each discrete data region within the range we
needed to scan. SEEK_DATA finds the start of the cached data region,
SEEK_HOLE finds the end of the region. These are byte based
interfaces that understand partially uptodate folio regions, and so
can iterate discrete sub-folio data regions directly. This largely
solved the problem of discovering the dirty regions we need to keep
the delalloc extent over.

However, to use mapping_seek_hole_data() without needing to export
it, we have to move all the delalloc extent cleanup to the iomap
core and so now the iomap core can clean up delayed allocation
extents in a safe, sane and filesystem neutral manner.

With all this done, the original data corruption never occurs
anymore, and we now have a generic mechanism for ensuring that page
cache writes do not do the wrong thing when writeback and reclaim
change the state of the physical extent and/or page cache contents
whilst the write is in progress.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

* tag 'xfs-iomap-stale-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs:
  xfs: drop write error injection is unfixable, remove it
  xfs: use iomap_valid method to detect stale cached iomaps
  iomap: write iomap validity checks
  xfs: xfs_bmap_punch_delalloc_range() should take a byte range
  iomap: buffered write failure should not truncate the page cache
  xfs,iomap: move delalloc punching to iomap
  xfs: use byte ranges for write cleanup ranges
  xfs: punching delalloc extents on write failure is racy
  xfs: write page faults in iomap are not buffered writes
2022-11-28 17:23:58 -08:00
Dave Chinner
6e8af15ccd xfs: drop write error injection is unfixable, remove it
With the changes to scan the page cache for dirty data to avoid data
corruptions from partial write cleanup racing with other page cache
operations, the drop writes error injection no longer works the same
way it used to and causes xfs/196 to fail. This is because xfs/196
writes to the file and populates the page cache before it turns on
the error injection and starts failing -overwrites-.

The result is that the original drop-writes code failed writes only
-after- overwriting the data in the cache, followed by invalidates
the cached data, then punching out the delalloc extent from under
that data.

On the surface, this looks fine. The problem is that page cache
invalidation *doesn't guarantee that it removes anything from the
page cache* and it doesn't change the dirty state of the folio. When
block size == page size and we do page aligned IO (as xfs/196 does)
everything happens to align perfectly and page cache invalidation
removes the single page folios that span the written data. Hence the
followup delalloc punch pass does not find cached data over that
range and it can punch the extent out.

IOWs, xfs/196 "works" for block size == page size with the new
code. I say "works", because it actually only works for the case
where IO is page aligned, and no data was read from disk before
writes occur. Because the moment we actually read data first, the
readahead code allocates multipage folios and suddenly the
invalidate code goes back to zeroing subfolio ranges without
changing dirty state.

Hence, with multipage folios in play, block size == page size is
functionally identical to block size < page size behaviour, and
drop-writes is manifestly broken w.r.t to this case. Invalidation of
a subfolio range doesn't result in the folio being removed from the
cache, just the range gets zeroed. Hence after we've sequentially
walked over a folio that we've dirtied (via write data) and then
invalidated, we end up with a dirty folio full of zeroed data.

And because the new code skips punching ranges that have dirty
folios covering them, we end up leaving the delalloc range intact
after failing all the writes. Hence failed writes now end up
writing zeroes to disk in the cases where invalidation zeroes folios
rather than removing them from cache.

This is a fundamental change of behaviour that is needed to avoid
the data corruption vectors that exist in the old write fail path,
and it renders the drop-writes injection non-functional and
unworkable as it stands.

As it is, I think the error injection is also now unnecessary, as
partial writes that need delalloc extent are going to be a lot more
common with stale iomap detection in place. Hence this patch removes
the drop-writes error injection completely. xfs/196 can remain for
testing kernels that don't have this data corruption fix, but those
that do will report:

xfs/196 3s ... [not run] XFS error injection drop_writes unknown on this kernel.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2022-11-29 09:09:17 +11:00
Dave Chinner
304a68b9c6 xfs: use iomap_valid method to detect stale cached iomaps
Now that iomap supports a mechanism to validate cached iomaps for
buffered write operations, hook it up to the XFS buffered write ops
so that we can avoid data corruptions that result from stale cached
iomaps. See:

https://lore.kernel.org/linux-xfs/20220817093627.GZ3600936@dread.disaster.area/

or the ->iomap_valid() introduction commit for exact details of the
corruption vector.

The validity cookie we store in the iomap is based on the type of
iomap we return. It is expected that the iomap->flags we set in
xfs_bmbt_to_iomap() is not perturbed by the iomap core and are
returned to us in the iomap passed via the .iomap_valid() callback.
This ensures that the validity cookie is always checking the correct
inode fork sequence numbers to detect potential changes that affect
the extent cached by the iomap.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2022-11-29 09:09:17 +11:00
Dave Chinner
7348b32233 xfs: xfs_bmap_punch_delalloc_range() should take a byte range
All the callers of xfs_bmap_punch_delalloc_range() jump through
hoops to convert a byte range to filesystem blocks before calling
xfs_bmap_punch_delalloc_range(). Instead, pass the byte range to
xfs_bmap_punch_delalloc_range() and have it do the conversion to
filesystem blocks internally.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2022-11-29 09:09:17 +11:00
Dave Chinner
9c7babf94a xfs,iomap: move delalloc punching to iomap
Because that's what Christoph wants for this error handling path
only XFS uses.

It requires a new iomap export for handling errors over delalloc
ranges. This is basically the XFS code as is stands, but even though
Christoph wants this as iomap funcitonality, we still have 
to call it from the filesystem specific ->iomap_end callback, and
call into the iomap code with yet another filesystem specific
callback to punch the delalloc extent within the defined ranges.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2022-11-23 12:44:38 +11:00
Dave Chinner
b71f889c18 xfs: use byte ranges for write cleanup ranges
xfs_buffered_write_iomap_end() currently converts the byte ranges
passed to it to filesystem blocks to pass them to the bmap code to
punch out delalloc blocks, but then has to convert filesytem
blocks back to byte ranges for page cache truncate.

We're about to make the page cache truncate go away and replace it
with a page cache walk, so having to convert everything to/from/to
filesystem blocks is messy and error-prone. It is much easier to
pass around byte ranges and convert to page indexes and/or
filesystem blocks only where those units are needed.

In preparation for the page cache walk being added, add a helper
that converts byte ranges to filesystem blocks and calls
xfs_bmap_punch_delalloc_range() and convert
xfs_buffered_write_iomap_end() to calculate limits in byte ranges.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2022-11-23 12:40:12 +11:00
Dave Chinner
198dd8aede xfs: punching delalloc extents on write failure is racy
xfs_buffered_write_iomap_end() has a comment about the safety of
punching delalloc extents based holding the IOLOCK_EXCL. This
comment is wrong, and punching delalloc extents is not race free.

When we punch out a delalloc extent after a write failure in
xfs_buffered_write_iomap_end(), we punch out the page cache with
truncate_pagecache_range() before we punch out the delalloc extents.
At this point, we only hold the IOLOCK_EXCL, so there is nothing
stopping mmap() write faults racing with this cleanup operation,
reinstantiating a folio over the range we are about to punch and
hence requiring the delalloc extent to be kept.

If this race condition is hit, we can end up with a dirty page in
the page cache that has no delalloc extent or space reservation
backing it. This leads to bad things happening at writeback time.

To avoid this race condition, we need the page cache truncation to
be atomic w.r.t. the extent manipulation. We can do this by holding
the mapping->invalidate_lock exclusively across this operation -
this will prevent new pages from being inserted into the page cache
whilst we are removing the pages and the backing extent and space
reservation.

Taking the mapping->invalidate_lock exclusively in the buffered
write IO path is safe - it naturally nests inside the IOLOCK (see
truncate and fallocate paths). iomap_zero_range() can be called from
under the mapping->invalidate_lock (from the truncate path via
either xfs_zero_eof() or xfs_truncate_page(), but iomap_zero_iter()
will not instantiate new delalloc pages (because it skips holes) and
hence will not ever need to punch out delalloc extents on failure.

Fix the locking issue, and clean up the code logic a little to avoid
unnecessary work if we didn't allocate the delalloc extent or wrote
the entire region we allocated.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2022-11-23 12:40:11 +11:00
Long Li
28b4b05963 xfs: fix incorrect i_nlink caused by inode racing
The following error occurred during the fsstress test:

XFS: Assertion failed: VFS_I(ip)->i_nlink >= 2, file: fs/xfs/xfs_inode.c, line: 2452

The problem was that inode race condition causes incorrect i_nlink to be
written to disk, and then it is read into memory. Consider the following
call graph, inodes that are marked as both XFS_IFLUSHING and
XFS_IRECLAIMABLE, i_nlink will be reset to 1 and then restored to original
value in xfs_reinit_inode(). Therefore, the i_nlink of directory on disk
may be set to 1.

  xfsaild
      xfs_inode_item_push
          xfs_iflush_cluster
              xfs_iflush
                  xfs_inode_to_disk

  xfs_iget
      xfs_iget_cache_hit
          xfs_iget_recycle
              xfs_reinit_inode
                  inode_init_always

xfs_reinit_inode() needs to hold the ILOCK_EXCL as it is changing internal
inode state and can race with other RCU protected inode lookups. On the
read side, xfs_iflush_cluster() grabs the ILOCK_SHARED while under rcu +
ip->i_flags_lock, and so xfs_iflush/xfs_inode_to_disk() are protected from
racing inode updates (during transactions) by that lock.

Fixes: ff7bebeb91 ("xfs: refactor the inode recycling code") # goes further back than this
Signed-off-by: Long Li <leo.lilong@huawei.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2022-11-21 10:00:01 -08:00
Jason A. Donenfeld
8032bf1233 treewide: use get_random_u32_below() instead of deprecated function
This is a simple mechanical transformation done by:

@@
expression E;
@@
- prandom_u32_max
+ get_random_u32_below
  (E)

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Reviewed-by: SeongJae Park <sj@kernel.org> # for damon
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> # for infiniband
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> # for arm
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-11-18 02:15:15 +01:00
Lukas Herbolt
64c80dfd04 xfs: Print XFS UUID on mount and umount events.
As of now only device names are printed out over __xfs_printk().
The device names are not persistent across reboots which in case
of searching for origin of corruption brings another task to properly
identify the devices. This patch add XFS UUID upon every mount/umount
event which will make the identification much easier.

Signed-off-by: Lukas Herbolt <lukas@herbolt.com>
[sandeen: rebase onto current upstream kernel]
Signed-off-by: Eric Sandeen <sandeen@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>
2022-11-16 19:20:21 -08:00
Long Li
59f6ab40fd xfs: fix sb write verify for lazysbcount
When lazysbcount is enabled, fsstress and loop mount/unmount test report
the following problems:

XFS (loop0): SB summary counter sanity check failed
XFS (loop0): Metadata corruption detected at xfs_sb_write_verify+0x13b/0x460,
	xfs_sb block 0x0
XFS (loop0): Unmount and run xfs_repair
XFS (loop0): First 128 bytes of corrupted metadata buffer:
00000000: 58 46 53 42 00 00 10 00 00 00 00 00 00 28 00 00  XFSB.........(..
00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
00000020: 69 fb 7c cd 5f dc 44 af 85 74 e0 cc d4 e3 34 5a  i.|._.D..t....4Z
00000030: 00 00 00 00 00 20 00 06 00 00 00 00 00 00 00 80  ..... ..........
00000040: 00 00 00 00 00 00 00 81 00 00 00 00 00 00 00 82  ................
00000050: 00 00 00 01 00 0a 00 00 00 00 00 04 00 00 00 00  ................
00000060: 00 00 0a 00 b4 b5 02 00 02 00 00 08 00 00 00 00  ................
00000070: 00 00 00 00 00 00 00 00 0c 09 09 03 14 00 00 19  ................
XFS (loop0): Corruption of in-memory data (0x8) detected at _xfs_buf_ioapply
	+0xe1e/0x10e0 (fs/xfs/xfs_buf.c:1580).  Shutting down filesystem.
XFS (loop0): Please unmount the filesystem and rectify the problem(s)
XFS (loop0): log mount/recovery failed: error -117
XFS (loop0): log mount failed

This corruption will shutdown the file system and the file system will
no longer be mountable. The following script can reproduce the problem,
but it may take a long time.

 #!/bin/bash

 device=/dev/sda
 testdir=/mnt/test
 round=0

 function fail()
 {
	 echo "$*"
	 exit 1
 }

 mkdir -p $testdir
 while [ $round -lt 10000 ]
 do
	 echo "******* round $round ********"
	 mkfs.xfs -f $device
	 mount $device $testdir || fail "mount failed!"
	 fsstress -d $testdir -l 0 -n 10000 -p 4 >/dev/null &
	 sleep 4
	 killall -w fsstress
	 umount $testdir
	 xfs_repair -e $device > /dev/null
	 if [ $? -eq 2 ];then
		 echo "ERR CODE 2: Dirty log exception during repair."
		 exit 1
	 fi
	 round=$(($round+1))
 done

With lazysbcount is enabled, There is no additional lock protection for
reading m_ifree and m_icount in xfs_log_sb(), if other cpu modifies the
m_ifree, this will make the m_ifree greater than m_icount. For example,
consider the following sequence and ifreedelta is postive:

 CPU0				 CPU1
 xfs_log_sb			 xfs_trans_unreserve_and_mod_sb
 ----------			 ------------------------------
 percpu_counter_sum(&mp->m_icount)
				 percpu_counter_add_batch(&mp->m_icount,
						idelta, XFS_ICOUNT_BATCH)
				 percpu_counter_add(&mp->m_ifree, ifreedelta);
 percpu_counter_sum(&mp->m_ifree)

After this, incorrect inode count (sb_ifree > sb_icount) will be writen to
the log. In the subsequent writing of sb, incorrect inode count (sb_ifree >
sb_icount) will fail to pass the boundary check in xfs_validate_sb_write()
that cause the file system shutdown.

When lazysbcount is enabled, we don't need to guarantee that Lazy sb
counters are completely correct, but we do need to guarantee that sb_ifree
<= sb_icount. On the other hand, the constraint that m_ifree <= m_icount
must be satisfied any time that there /cannot/ be other threads allocating
or freeing inode chunks. If the constraint is violated under these
circumstances, sb_i{count,free} (the ondisk superblock inode counters)
maybe incorrect and need to be marked sick at unmount, the count will
be rebuilt on the next mount.

Fixes: 8756a5af18 ("libxfs: add more bounds checking to sb sanity checks")
Signed-off-by: Long Li <leo.lilong@huawei.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2022-11-16 19:20:20 -08:00
Darrick J. Wong
2653d53345 xfs: fix incorrect error-out in xfs_remove
Clean up resources if resetting the dotdot entry doesn't succeed.
Observed through code inspection.

Fixes: 5838d0356b ("xfs: reset child dir '..' entry when unlinking child")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Andrey Albershteyn <aalbersh@redhat.com>
2022-11-16 19:20:20 -08:00
Darrick J. Wong
f36b954a1f xfs: check inode core when scrubbing metadata files
Metadata files (e.g. realtime bitmaps and quota files) do not show up in
the bulkstat output, which means that scrub-by-handle does not work;
they can only be checked through a specific scrub type.  Therefore, each
scrub type calls xchk_metadata_inode_forks to check the metadata for
whatever's in the file.

Unfortunately, that function doesn't actually check the inode record
itself.  Refactor the function a bit to make that happen.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-11-16 16:11:51 -08:00
Darrick J. Wong
bd5ab5f987 xfs: don't warn about files that are exactly s_maxbytes long
We can handle files that are exactly s_maxbytes bytes long; we just
can't handle anything larger than that.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-11-16 16:11:51 -08:00
Darrick J. Wong
5eef46358f xfs: teach scrub to flag non-extents format cow forks
CoW forks only exist in memory, which means that they can only ever have
an incore extent tree.  Hence they must always be FMT_EXTENTS, so check
this when we're scrubbing them.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-11-16 15:25:05 -08:00
Darrick J. Wong
3178553701 xfs: check that CoW fork extents are not shared
Ensure that extents in an inode's CoW fork are not marked as shared in
the refcount btree.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-11-16 15:25:04 -08:00
Darrick J. Wong
f23c40443d xfs: check quota files for unwritten extents
Teach scrub to flag quota files containing unwritten extents.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-11-16 15:25:04 -08:00
Darrick J. Wong
830ffa09fb xfs: block map scrub should handle incore delalloc reservations
Enhance the block map scrubber to check delayed allocation reservations.
Though there are no physical space allocations to check, we do need to
make sure that the range of file offsets being mapped are correct, and
to bump the lastoff cursor so that key order checking works correctly.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-11-16 15:25:04 -08:00
Darrick J. Wong
6a5777865e xfs: teach scrub to check for adjacent bmaps when rmap larger than bmap
When scrub is checking file fork mappings against rmap records and
the rmap record starts before or ends after the bmap record, check the
adjacent bmap records to make sure that they're adjacent to the one
we're checking.  This helps us to detect cases where the rmaps cover
territory that the bmaps do not.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-11-16 15:25:04 -08:00
Darrick J. Wong
033985b6fe xfs: fix perag loop in xchk_bmap_check_rmaps
sparse complains that we can return an uninitialized error from this
function and that pag could be uninitialized.  We know that there are no
zero-AG filesystems and hence we had to call xchk_bmap_check_ag_rmaps at
least once, so this is not actually possible, but I'm too worn out from
automated complaints from unsophisticated AIs so let's just fix this and
move on to more interesting problems, eh?

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-11-16 15:25:04 -08:00