1. 07 Dec, 2023 40 commits
    • Zhang Tianci's avatar
      xfs: update dir3 leaf block metadata after swap · 5759aa4f
      Zhang Tianci authored
      xfs_da3_swap_lastblock() copy the last block content to the dead block,
      but do not update the metadata in it. We need update some metadata
      for some kinds of type block, such as dir3 leafn block records its
      blkno, we shall update it to the dead block blkno. Otherwise,
      before write the xfs_buf to disk, the verify_write() will fail in
      blk_hdr->blkno != xfs_buf->b_bn, then xfs will be shutdown.
      
      We will get this warning:
      
        XFS (dm-0): Metadata corruption detected at xfs_dir3_leaf_verify+0xa8/0xe0 [xfs], xfs_dir3_leafn block 0x178
        XFS (dm-0): Unmount and run xfs_repair
        XFS (dm-0): First 128 bytes of corrupted metadata buffer:
        00000000e80f1917: 00 80 00 0b 00 80 00 07 3d ff 00 00 00 00 00 00  ........=.......
        000000009604c005: 00 00 00 00 00 00 01 a0 00 00 00 00 00 00 00 00  ................
        000000006b6fb2bf: e4 44 e3 97 b5 64 44 41 8b 84 60 0e 50 43 d9 bf  .D...dDA..`.PC..
        00000000678978a2: 00 00 00 00 00 00 00 83 01 73 00 93 00 00 00 00  .........s......
        00000000b28b247c: 99 29 1d 38 00 00 00 00 99 29 1d 40 00 00 00 00  .).8.....).@....
        000000002b2a662c: 99 29 1d 48 00 00 00 00 99 49 11 00 00 00 00 00  .).H.....I......
        00000000ea2ffbb8: 99 49 11 08 00 00 45 25 99 49 11 10 00 00 48 fe  .I....E%.I....H.
        0000000069e86440: 99 49 11 18 00 00 4c 6b 99 49 11 20 00 00 4d 97  .I....Lk.I. ..M.
        XFS (dm-0): xfs_do_force_shutdown(0x8) called from line 1423 of file fs/xfs/xfs_buf.c.  Return address = 00000000c0ff63c1
        XFS (dm-0): Corruption of in-memory data detected.  Shutting down filesystem
        XFS (dm-0): Please umount the filesystem and rectify the problem(s)
      
      >From the log above, we know xfs_buf->b_no is 0x178, but the block's hdr record
      its blkno is 0x1a0.
      
      Fixes: 24df33b4 ("xfs: add CRC checking to dir2 leaf blocks")
      Signed-off-by: default avatarZhang Tianci <zhangtianci.1997@bytedance.com>
      Suggested-by: default avatarDave Chinner <david@fromorbit.com>
      Reviewed-by: default avatar"Darrick J. Wong" <djwong@kernel.org>
      Signed-off-by: default avatarChandan Babu R <chandanbabu@kernel.org>
      5759aa4f
    • Jiachen Zhang's avatar
      xfs: ensure logflagsp is initialized in xfs_bmap_del_extent_real · e6af9c98
      Jiachen Zhang authored
      In the case of returning -ENOSPC, ensure logflagsp is initialized by 0.
      Otherwise the caller __xfs_bunmapi will set uninitialized illegal
      tmp_logflags value into xfs log, which might cause unpredictable error
      in the log recovery procedure.
      
      Also, remove the flags variable and set the *logflagsp directly, so that
      the code should be more robust in the long run.
      
      Fixes: 1b24b633 ("xfs: move some more code into xfs_bmap_del_extent_real")
      Signed-off-by: default avatarJiachen Zhang <zhangjiachen.jaycee@bytedance.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatar"Darrick J. Wong" <djwong@kernel.org>
      Signed-off-by: default avatarChandan Babu R <chandanbabu@kernel.org>
      e6af9c98
    • Christoph Hellwig's avatar
      xfs: clean up xfs_fsops.h · 08e54ca4
      Christoph Hellwig authored
      Use struct types instead of typedefs so that the header can be included
      with pulling in the headers that define the typedefs, and remove the
      pointless externs.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatar"Darrick J. Wong" <djwong@kernel.org>
      Signed-off-by: default avatarChandan Babu R <chandanbabu@kernel.org>
      08e54ca4
    • Christoph Hellwig's avatar
      xfs: clean up the xfs_reserve_blocks interface · 646ddf0c
      Christoph Hellwig authored
      xfs_reserve_blocks has a very odd interface that can only be explained
      by it directly deriving from the IRIX fcntl handler back in the day.
      
      Split reporting out the reserved blocks out of xfs_reserve_blocks into
      the only caller that cares.  This means that the value reported from
      XFS_IOC_SET_RESBLKS isn't atomically sampled in the same critical
      section as when it was set anymore, but as the values could change
      right after setting them anyway that does not matter.  It does
      provide atomic sampling of both values for XFS_IOC_GET_RESBLKS now,
      though.
      
      Also pass a normal scalar integer value for the requested value instead
      of the pointless pointer.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatar"Darrick J. Wong" <djwong@kernel.org>
      Signed-off-by: default avatarChandan Babu R <chandanbabu@kernel.org>
      646ddf0c
    • Christoph Hellwig's avatar
      xfs: clean up the XFS_IOC_FSCOUNTS handler · c2c2620d
      Christoph Hellwig authored
      Split XFS_IOC_FSCOUNTS out of the main xfs_file_ioctl function, and
      merge the xfs_fs_counts helper into the ioctl handler.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatar"Darrick J. Wong" <djwong@kernel.org>
      Signed-off-by: default avatarChandan Babu R <chandanbabu@kernel.org>
      c2c2620d
    • Christoph Hellwig's avatar
      xfs: clean up the XFS_IOC_{GS}ET_RESBLKS handler · 64f08b15
      Christoph Hellwig authored
      The XFS_IOC_GET_RESBLKS and XFS_IOC_SET_RESBLKS already share a fair
      amount of code, and will share even more soon.  Move the logic for both
      of them out of the main xfs_file_ioctl function into a
      xfs_ioctl_getset_resblocks helper to share the code and prepare for
      additional changes.
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatar"Darrick J. Wong" <djwong@kernel.org>
      Signed-off-by: default avatarChandan Babu R <chandanbabu@kernel.org>
      64f08b15
    • Bagas Sanjaya's avatar
      Documentation: xfs: consolidate XFS docs into its own subdirectory · 011f129f
      Bagas Sanjaya authored
      XFS docs are currently in upper-level Documentation/filesystems.
      Although these are currently 4 docs, they are already outstanding as
      a group and can be moved to its own subdirectory.
      
      Consolidate them into Documentation/filesystems/xfs/.
      Signed-off-by: default avatarBagas Sanjaya <bagasdotme@gmail.com>
      Reviewed-by: default avatarBill O'Donnell <bodonnel@redhat.com>
      Reviewed-by: default avatar"Darrick J. Wong" <djwong@kernel.org>
      Signed-off-by: default avatarChandan Babu R <chandanbabu@kernel.org>
      011f129f
    • Shiyang Ruan's avatar
      mm, pmem, xfs: Introduce MF_MEM_PRE_REMOVE for unbind · fa422b35
      Shiyang Ruan authored
      Now, if we suddenly remove a PMEM device(by calling unbind) which
      contains FSDAX while programs are still accessing data in this device,
      e.g.:
      ```
       $FSSTRESS_PROG -d $SCRATCH_MNT -n 99999 -p 4 &
       # $FSX_PROG -N 1000000 -o 8192 -l 500000 $SCRATCH_MNT/t001 &
       echo "pfn1.1" > /sys/bus/nd/drivers/nd_pmem/unbind
      ```
      it could come into an unacceptable state:
        1. device has gone but mount point still exists, and umount will fail
             with "target is busy"
        2. programs will hang and cannot be killed
        3. may crash with NULL pointer dereference
      
      To fix this, we introduce a MF_MEM_PRE_REMOVE flag to let it know that we
      are going to remove the whole device, and make sure all related processes
      could be notified so that they could end up gracefully.
      
      This patch is inspired by Dan's "mm, dax, pmem: Introduce
      dev_pagemap_failure()"[1].  With the help of dax_holder and
      ->notify_failure() mechanism, the pmem driver is able to ask filesystem
      on it to unmap all files in use, and notify processes who are using
      those files.
      
      Call trace:
      trigger unbind
       -> unbind_store()
        -> ... (skip)
         -> devres_release_all()
          -> kill_dax()
           -> dax_holder_notify_failure(dax_dev, 0, U64_MAX, MF_MEM_PRE_REMOVE)
            -> xfs_dax_notify_failure()
            `-> freeze_super()             // freeze (kernel call)
            `-> do xfs rmap
            ` -> mf_dax_kill_procs()
            `  -> collect_procs_fsdax()    // all associated processes
            `  -> unmap_and_kill()
            ` -> invalidate_inode_pages2_range() // drop file's cache
            `-> thaw_super()               // thaw (both kernel & user call)
      
      Introduce MF_MEM_PRE_REMOVE to let filesystem know this is a remove
      event.  Use the exclusive freeze/thaw[2] to lock the filesystem to prevent
      new dax mapping from being created.  Do not shutdown filesystem directly
      if configuration is not supported, or if failure range includes metadata
      area.  Make sure all files and processes(not only the current progress)
      are handled correctly.  Also drop the cache of associated files before
      pmem is removed.
      
      [1]: https://lore.kernel.org/linux-mm/161604050314.1463742.14151665140035795571.stgit@dwillia2-desk3.amr.corp.intel.com/
      [2]: https://lore.kernel.org/linux-xfs/169116275623.3187159.16862410128731457358.stg-ugh@frogsfrogsfrogs/Signed-off-by: default avatarShiyang Ruan <ruansy.fnst@fujitsu.com>
      Reviewed-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarDan Williams <dan.j.williams@intel.com>
      Signed-off-by: default avatarChandan Babu R <chandanbabu@kernel.org>
      fa422b35
    • Chandan Babu R's avatar
      Merge tag 'repair-auto-reap-space-reservations-6.8_2023-12-06' of... · 49391d13
      Chandan Babu R authored
      Merge tag 'repair-auto-reap-space-reservations-6.8_2023-12-06' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.8-mergeA
      
      xfs: reserve disk space for online repairs
      
      Online repair fixes metadata structures by writing a new copy out to
      disk and atomically committing the new structure into the filesystem.
      For this to work, we need to reserve all the space we're going to need
      ahead of time so that the atomic commit transaction is as small as
      possible.  We also require the reserved space to be freed if the system
      goes down, or if we decide not to commit the repair, or if we reserve
      too much space.
      
      To keep the atomic commit transaction as small as possible, we would
      like to allocate some space and simultaneously schedule automatic
      reaping of the reserved space, even on log recovery.  EFIs are the
      mechanism to get us there, but we need to use them in a novel manner.
      Once we allocate the space, we want to hold on to the EFI (relogging as
      necessary) until we can commit or cancel the repair.  EFIs for written
      committed blocks need to go away, but unwritten or uncommitted blocks
      can be freed like normal.
      
      Earlier versions of this patchset directly manipulated the log items,
      but Dave thought that to be a layering violation.  For v27, I've
      modified the defer ops handling code to be capable of pausing a deferred
      work item.  Log intent items are created as they always have been, but
      paused items are pushed onto a side list when finishing deferred work
      items, and pushed back onto the transaction after that.  Log intent done
      item are not created for paused work.
      
      The second part adds a "stale" flag to the EFI so that the repair
      reservation code can dispose of an EFI the normal way, but without the
      space actually being freed.
      
      This has been lightly tested with fstests.  Enjoy!
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Signed-off-by: default avatarChandan Babu R <chandanbabu@kernel.org>
      
      * tag 'repair-auto-reap-space-reservations-6.8_2023-12-06' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux:
        xfs: force small EFIs for reaping btree extents
        xfs: log EFIs for all btree blocks being used to stage a btree
        xfs: implement block reservation accounting for btrees we're staging
        xfs: remove unused fields from struct xbtree_ifakeroot
        xfs: automatic freeing of freshly allocated unwritten space
        xfs: remove __xfs_free_extent_later
        xfs: allow pausing of pending deferred work items
        xfs: don't append work items to logged xfs_defer_pending objects
      49391d13
    • Chandan Babu R's avatar
      Merge tag 'scrub-livelock-prevention-6.8_2023-12-06' of... · dec0224b
      Chandan Babu R authored
      Merge tag 'scrub-livelock-prevention-6.8_2023-12-06' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.8-mergeA
      
      xfs: prevent livelocks in xchk_iget
      
      Prevent scrub from live locking in xchk_iget if there's a cycle in the
      inobt by allocating an empty transaction.
      
      This has been lightly tested with fstests.  Enjoy!
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Signed-off-by: default avatarChandan Babu R <chandanbabu@kernel.org>
      Signed-off-by: default avatarChandan Babu R <chandanbabu@kernel.org>
      
      * tag 'scrub-livelock-prevention-6.8_2023-12-06' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux:
        xfs: make xchk_iget safer in the presence of corrupt inode btrees
      dec0224b
    • Chandan Babu R's avatar
      Merge tag 'defer-elide-create-done-6.8_2023-12-06' of... · 9f334526
      Chandan Babu R authored
      Merge tag 'defer-elide-create-done-6.8_2023-12-06' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.8-mergeA
      
      xfs: elide defer work ->create_done if no intent
      
      Christoph pointed out that the defer ops machinery doesn't need to call
      ->create_done if the deferred work item didn't generate a log intent
      item in the first place.  Let's clean that up and save an indirect call
      in the non-logged xattr update call path.
      
      This has been lightly tested with fstests.  Enjoy!
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Signed-off-by: default avatarChandan Babu R <chandanbabu@kernel.org>
      
      * tag 'defer-elide-create-done-6.8_2023-12-06' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux:
        xfs: elide ->create_done calls for unlogged deferred work
        xfs: document what LARP means
      9f334526
    • Chandan Babu R's avatar
      Merge tag 'fix-rtmount-overflows-6.8_2023-12-06' of... · 47c460ef
      Chandan Babu R authored
      Merge tag 'fix-rtmount-overflows-6.8_2023-12-06' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.8-mergeA
      
      xfs: fix realtime geometry integer overflows
      
      While reading through the realtime geometry support code in xfsprogs, I
      noticed a discrepancy between the sb_rextslog computation used when
      writing out the superblock during mkfs and the validation code used in
      xfs_repair.  This discrepancy would lead to system failure for a runt rt
      volume having more than 1 rt block but zero rt extents in length.  Most
      people aren't going to configure a 1M extent size for their 360k rt
      floppy disk volume, but I did!
      
      In the process of studying that code, it occurred to me that there is a
      second bug in the computation -- the use of highbit32 for a 64-bit
      value means that the upper 32 bits are not considered in the search for
      a high bit.  This causes the creation of a realtime summary file that is
      the wrong length.  If rextents is a multiple of U32_MAX then this will
      appear to work fine because highbit32 returns -1 for an input of 0; but
      for all other cases the rt summary is undersized, leading to failures.
      
      Fix the first problem by standardizing the computation with a helper in
      libxfs; and the second problem by correcting the computation.  This will
      cause any existing rt volumes larger than 2^32 blocks to fail validation
      but they probably were already crashing anyway.
      
      This has been lightly tested with fstests.  Enjoy!
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Signed-off-by: default avatarChandan Babu R <chandanbabu@kernel.org>
      
      * tag 'fix-rtmount-overflows-6.8_2023-12-06' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux:
        xfs: don't allow overly small or large realtime volumes
        xfs: fix 32-bit truncation in xfs_compute_rextslog
        xfs: make rextslog computation consistent with mkfs
      47c460ef
    • Chandan Babu R's avatar
      Merge tag 'reconstruct-defer-cleanups-6.8_2023-12-06' of... · 34d38666
      Chandan Babu R authored
      Merge tag 'reconstruct-defer-cleanups-6.8_2023-12-06' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.8-mergeA
      
      xfs: continue removing defer item boilerplate
      
      Now that we've restructured log intent item recovery to reconstruct the
      incore deferred work state, apply further cleanups to that code to
      remove boilerplate that is duplicated across all the _item.c files.
      Having done that, collapse a bunch of trivial helpers to reduce the
      overall call chain.  That enables us to refactor the relog code so that
      the ->relog_item implementations only have to know how to format the
      implementation-specific data encoded in an intent item and don't
      themselves have to handle the log item juggling.
      
      This has been lightly tested with fstests.  Enjoy!
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Signed-off-by: default avatarChandan Babu R <chandanbabu@kernel.org>
      
      * tag 'reconstruct-defer-cleanups-6.8_2023-12-06' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux:
        xfs: move ->iop_relog to struct xfs_defer_op_type
        xfs: collapse the ->create_done functions
        xfs: hoist xfs_trans_add_item calls to defer ops functions
        xfs: clean out XFS_LI_DIRTY setting boilerplate from ->iop_relog
        xfs: use xfs_defer_create_done for the relogging operation
        xfs: hoist ->create_intent boilerplate to its callsite
        xfs: collapse the ->finish_item helpers
        xfs: hoist intent done flag setting to ->finish_item callsite
        xfs: don't set XFS_TRANS_HAS_INTENT_DONE when there's no ATTRD log item
      34d38666
    • Chandan Babu R's avatar
      Merge tag 'reconstruct-defer-work-6.8_2023-12-06' of... · 6b4ffe97
      Chandan Babu R authored
      Merge tag 'reconstruct-defer-work-6.8_2023-12-06' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into xfs-6.8-mergeA
      
      xfs: log intent item recovery should reconstruct defer work state
      
      Long Li reported a KASAN report from a UAF when intent recovery fails:
      
       ==================================================================
       BUG: KASAN: slab-use-after-free in xfs_cui_release+0xb7/0xc0
       Read of size 4 at addr ffff888012575e60 by task kworker/u8:3/103
       CPU: 3 PID: 103 Comm: kworker/u8:3 Not tainted 6.4.0-rc7-next-20230619-00003-g94543a53f9a4-dirty #166
       Workqueue: xfs-cil/sda xlog_cil_push_work
       Call Trace:
        <TASK>
        dump_stack_lvl+0x50/0x70
        print_report+0xc2/0x600
        kasan_report+0xb6/0xe0
        xfs_cui_release+0xb7/0xc0
        xfs_cud_item_release+0x3c/0x90
        xfs_trans_committed_bulk+0x2d5/0x7f0
        xlog_cil_committed+0xaba/0xf20
        xlog_cil_push_work+0x1a60/0x2360
        process_one_work+0x78e/0x1140
        worker_thread+0x58b/0xf60
        kthread+0x2cd/0x3c0
        ret_from_fork+0x1f/0x30
        </TASK>
      
       Allocated by task 531:
        kasan_save_stack+0x22/0x40
        kasan_set_track+0x25/0x30
        __kasan_slab_alloc+0x55/0x60
        kmem_cache_alloc+0x195/0x5f0
        xfs_cui_init+0x198/0x1d0
        xlog_recover_cui_commit_pass2+0x133/0x5f0
        xlog_recover_items_pass2+0x107/0x230
        xlog_recover_commit_trans+0x3e7/0x9c0
        xlog_recovery_process_trans+0x140/0x1d0
        xlog_recover_process_ophdr+0x1a0/0x3d0
        xlog_recover_process_data+0x108/0x2d0
        xlog_recover_process+0x1f6/0x280
        xlog_do_recovery_pass+0x609/0xdb0
        xlog_do_log_recovery+0x84/0xe0
        xlog_do_recover+0x7d/0x470
        xlog_recover+0x25f/0x490
        xfs_log_mount+0x2dd/0x6f0
        xfs_mountfs+0x11ce/0x1e70
        xfs_fs_fill_super+0x10ec/0x1b20
        get_tree_bdev+0x3c8/0x730
        vfs_get_tree+0x89/0x2c0
        path_mount+0xecf/0x1800
        do_mount+0xf3/0x110
        __x64_sys_mount+0x154/0x1f0
        do_syscall_64+0x39/0x80
        entry_SYSCALL_64_after_hwframe+0x63/0xcd
      
       Freed by task 531:
        kasan_save_stack+0x22/0x40
        kasan_set_track+0x25/0x30
        kasan_save_free_info+0x2b/0x40
        __kasan_slab_free+0x114/0x1b0
        kmem_cache_free+0xf8/0x510
        xfs_cui_item_free+0x95/0xb0
        xfs_cui_release+0x86/0xc0
        xlog_recover_cancel_intents.isra.0+0xf8/0x210
        xlog_recover_finish+0x7e7/0x980
        xfs_log_mount_finish+0x2bb/0x4a0
        xfs_mountfs+0x14bf/0x1e70
        xfs_fs_fill_super+0x10ec/0x1b20
        get_tree_bdev+0x3c8/0x730
        vfs_get_tree+0x89/0x2c0
        path_mount+0xecf/0x1800
        do_mount+0xf3/0x110
        __x64_sys_mount+0x154/0x1f0
        do_syscall_64+0x39/0x80
        entry_SYSCALL_64_after_hwframe+0x63/0xcd
      
       The buggy address belongs to the object at ffff888012575dc8
        which belongs to the cache xfs_cui_item of size 432
       The buggy address is located 152 bytes inside of
        freed 432-byte region [ffff888012575dc8, ffff888012575f78)
      
       The buggy address belongs to the physical page:
       page:ffffea0000495d00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888012576208 pfn:0x12574
       head:ffffea0000495d00 order:2 entire_mapcount:0 nr_pages_mapped:0 pincount:0
       flags: 0x1fffff80010200(slab|head|node=0|zone=1|lastcpupid=0x1fffff)
       page_type: 0xffffffff()
       raw: 001fffff80010200 ffff888012092f40 ffff888014570150 ffff888014570150
       raw: ffff888012576208 00000000001e0010 00000001ffffffff 0000000000000000
       page dumped because: kasan: bad access detected
      
       Memory state around the buggy address:
        ffff888012575d00: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc
        ffff888012575d80: fc fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb
       >ffff888012575e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                              ^
        ffff888012575e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
        ffff888012575f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc
       ==================================================================
      
      "If process intents fails, intent items left in AIL will be delete
      from AIL and freed in error handling, even intent items that have been
      recovered and created done items. After this, uaf will be triggered when
      done item committed, because at this point the released intent item will
      be accessed.
      
      xlog_recover_finish                     xlog_cil_push_work
      ----------------------------            ---------------------------
      xlog_recover_process_intents
        xfs_cui_item_recover//cui_refcount == 1
          xfs_trans_get_cud
          xfs_trans_commit
            <add cud item to cil>
        xfs_cui_item_recover
          <error occurred and return>
      xlog_recover_cancel_intents
        xfs_cui_release     //cui_refcount == 0
          xfs_cui_item_free //free cui
        <release other intent items>
      xlog_force_shutdown   //shutdown
                                     <...>
                                              <push items in cil>
                                              xlog_cil_committed
                                                xfs_cud_item_release
                                                  xfs_cui_release // UAF
      
      "Intent log items are created with a reference count of 2, one for the
      creator, and one for the intent done object. Log recovery explicitly
      drops the creator reference after it is inserted into the AIL, but it
      then processes the log item as if it also owns the intent-done reference.
      
      "The code in ->iop_recovery should assume that it passes the reference
      to the done intent, we can remove the intent item from the AIL after
      creating the done-intent, but if that code fails before creating the
      done-intent then it needs to release the intent reference by log recovery
      itself.
      
      "That way when we go to cancel the intent, the only intents we find in
      the AIL are the ones we know have not been processed yet and hence we
      can safely drop both the creator and the intent done reference from
      xlog_recover_cancel_intents().
      
      "Hence if we remove the intent from the list of intents that need to
      be recovered after we have done the initial recovery, we acheive two
      things:
      
      "1. the tail of the log can be moved forward with the commit of the
      done intent or new intent to continue the operation, and
      
      "2. We avoid the problem of trying to determine how many reference
      counts we need to drop from intent recovery cancelling because we
      never come across intents we've actually attempted recovery on."
      
      Restated: The cause of the UAF is that xlog_recover_cancel_intents
      thinks that it owns the refcount on any intent item in the AIL, and that
      it's always safe to release these intent items.  This is not true after
      the recovery function creates an log intent done item and points it at
      the log intent item because releasing the done item always releases the
      intent item.
      
      The runtime defer ops code avoids all this by tracking both the log
      intent and the intent done items, and releasing only the intent done
      item if both have been created.  Long Li proposed fixing this by adding
      state flags, but I have a more comprehensive fix.
      
      First, observe that the latter half of the intent _recover functions are
      nearly open-coded versions of the corresponding _finish_one function
      that uses an onstack deferred work item to single-step through the item.
      
      Second, notice that the recover function is not an exact match because
      of the odd behavior that unfinished recovered work items are relogged
      with separate log intent items instead of a single new log intent item,
      which is what the defer ops machinery does.
      
      Dave and I have long suspected that recovery should be reconstructing
      the defer work state from what's in the recovered intent item.  Now we
      finally have an excuse to refactor the code to do that.
      
      This series starts by fixing a resource leak in LARP recovery.  We fix
      the bug that Long Li reported by switching the intent recovery code to
      construct chains of xfs_defer_pending objects and then using the defer
      pending objects to track the intent/done item ownership.  Finally, we
      clean up the code to reconstruct the exact incore state, which means we
      can remove all the opencoded _recover code, which makes maintaining log
      items much easier.
      
      v2: minor changes per review comments
      v3: pick up more rvb tags, fix build errors
      
      This has been lightly tested with fstests.  Enjoy!
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Signed-off-by: default avatarChandan Babu R <chandanbabu@kernel.org>
      
      * tag 'reconstruct-defer-work-6.8_2023-12-06' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux:
        xfs: move ->iop_recover to xfs_defer_op_type
        xfs: use xfs_defer_finish_one to finish recovered work items
        xfs: dump the recovered xattri log item if corruption happens
        xfs: recreate work items when recovering intent items
        xfs: transfer recovered intent item ownership in ->iop_recover
        xfs: pass the xfs_defer_pending object to iop_recover
        xfs: use xfs_defer_pending objects to recover intent items
        xfs: don't leak recovered attri intent items
      6b4ffe97
    • Darrick J. Wong's avatar
      xfs: force small EFIs for reaping btree extents · 3f3cec03
      Darrick J. Wong authored
      Introduce the concept of a defer ops barrier to separate consecutively
      queued pending work items of the same type.  With a barrier in place,
      the two work items will be tracked separately, and receive separate log
      intent items.  The goal here is to prevent reaping of old metadata
      blocks from creating unnecessarily huge EFIs that could then run the
      risk of overflowing the scrub transaction.
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      3f3cec03
    • Darrick J. Wong's avatar
      xfs: log EFIs for all btree blocks being used to stage a btree · 6bb9ea8e
      Darrick J. Wong authored
      We need to log EFIs for every extent that we allocate for the purpose of
      staging a new btree so that if we fail then the blocks will be freed
      during log recovery.  Use the autoreaping mechanism provided by the
      previous patch to attach paused freeing work to the scrub transaction.
      We can then mark the EFIs stale if we decide to commit the new btree, or
      we can unpause the EFIs if we decide to abort the repair.
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      6bb9ea8e
    • Darrick J. Wong's avatar
      xfs: implement block reservation accounting for btrees we're staging · be408417
      Darrick J. Wong authored
      Create a new xrep_newbt structure to encapsulate a fake root for
      creating a staged btree cursor as well as to track all the blocks that
      we need to reserve in order to build that btree.
      
      As for the particular choice of lowspace thresholds and btree block
      slack factors -- at this point one could say that the thresholds in
      online repair come from bulkload_estimate_ag_slack in xfs_repair[1].
      But that's not the entire story, since the offline btree rebuilding
      code in xfs_repair was merged as a retroport of the online btree code
      in this patchset!
      
      Before xfs_btree_staging.[ch] came along, xfs_repair determined the
      slack factor (aka the number of slots to leave unfilled in each new
      btree block) via open-coded logic in repair/phase5.c[2].  At that point
      the slack factors were arbitrary quantities per btree.  The rmapbt
      automatically left 10 slots free; everything else left zero.
      
      That had a noticeable effect on performance straight after mounting
      because adding records to /any/ btree would result in splits.  A few
      years ago when this patch was first written, Dave and I decided that
      repair should generate btree blocks that were 75% full unless space was
      tight, in which case it should try to fill the blocks to nearly full.
      We defined tight as ~10% free to avoid repair failures but settled on
      3/32 (~9%) to avoid div64.
      
      IOWs, we mostly pulled the thresholds out of thin air.  We've been
      QAing with those geometry numbers ever since. ;)
      
      Link: https://git.kernel.org/pub/scm/fs/xfs/xfsprogs-dev.git/tree/repair/bulkload.c?h=v6.5.0#n114
      Link: https://git.kernel.org/pub/scm/fs/xfs/xfsprogs-dev.git/tree/repair/phase5.c?h=v4.19.0#n1349Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
      be408417
    • Darrick J. Wong's avatar
      xfs: remove unused fields from struct xbtree_ifakeroot · 4c8ecd1c
      Darrick J. Wong authored
      Remove these unused fields since nobody uses them.  They should have
      been removed years ago in a different cleanup series from Christoph
      Hellwig.
      
      Fixes: daf83964 ("xfs: move the per-fork nextents fields into struct xfs_ifork")
      Fixes: f7e67b20 ("xfs: move the fork format fields into struct xfs_ifork")
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
      4c8ecd1c
    • Darrick J. Wong's avatar
      xfs: automatic freeing of freshly allocated unwritten space · e3042be3
      Darrick J. Wong authored
      As mentioned in the previous commit, online repair wants to allocate
      space to write out a new metadata structure, and it also wants to hedge
      against system crashes during repairs by logging (and later cancelling)
      EFIs to free the space if we crash before committing the new data
      structure.
      
      Therefore, create a trio of functions to schedule automatic reaping of
      freshly allocated unwritten space.  xfs_alloc_schedule_autoreap creates
      a paused EFI representing the space we just allocated.  Once the
      allocations are made and the autoreaps scheduled, we can start writing
      to disk.
      
      If the writes succeed, xfs_alloc_cancel_autoreap marks the EFI work
      items as stale and unpauses the pending deferred work item.  Assuming
      that's done in the same transaction that commits the new structure into
      the filesystem, we guarantee that either the new object is fully
      visible, or that all the space gets reclaimed.
      
      If the writes succeed but only part of an extent was used, repair must
      call the same _cancel_autoreap function to kill the first EFI and then
      log a new EFI to free the unused space.  The first EFI is already
      committed, so it cannot be changed.
      
      For full extents that aren't used, xfs_alloc_commit_autoreap will
      unpause the EFI, which results in the space being freed during the next
      _defer_finish cycle.
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      e3042be3
    • Darrick J. Wong's avatar
      xfs: remove __xfs_free_extent_later · 4c88fef3
      Darrick J. Wong authored
      xfs_free_extent_later is a trivial helper, so remove it to reduce the
      amount of thinking required to understand the deferred freeing
      interface.  This will make it easier to introduce automatic reaping of
      speculative allocations in the next patch.
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      4c88fef3
    • Darrick J. Wong's avatar
      xfs: allow pausing of pending deferred work items · 4dffb2cb
      Darrick J. Wong authored
      Traditionally, all pending deferred work attached to a transaction is
      finished when one of the xfs_defer_finish* functions is called.
      However, online repair wants to be able to allocate space for a new data
      structure, format a new metadata structure into the allocated space, and
      commit that into the filesystem.
      
      As a hedge against system crashes during repairs, we also want to log
      some EFI items for the allocated space speculatively, and cancel them if
      we elect to commit the new data structure.
      
      Therefore, introduce the idea of pausing a pending deferred work item.
      Log intent items are still created for paused items and relogged as
      necessary.  However, paused items are pushed onto a side list before we
      start calling ->finish_item, and the whole list is reattach to the
      transaction afterwards.  New work items are never attached to paused
      pending items.
      
      Modify xfs_defer_cancel to clean up pending deferred work items holding
      a log intent item but not a log intent done item, since that is now
      possible.
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      4dffb2cb
    • Darrick J. Wong's avatar
      xfs: don't append work items to logged xfs_defer_pending objects · 6b126139
      Darrick J. Wong authored
      When someone tries to add a deferred work item to xfs_defer_add, it will
      try to attach the work item to the most recently added xfs_defer_pending
      object attached to the transaction.  However, it doesn't check if the
      pending object has a log intent item attached to it.  This is incorrect
      behavior because we cannot add more work to an object that has already
      been committed to the ondisk log.
      
      Therefore, change the behavior not to append to pending items with a non
      null dfp_intent.  In practice this has not been an issue because the
      only way xfs_defer_add gets called after log intent items have been
      committed is from the defer ops ->finish_item functions themselves, and
      the @dop_pending isolation in xfs_defer_finish_noroll protects the
      pending items that have already been logged.
      
      However, the next patch will add the ability to pause a deferred extent
      free object during online btree rebuilding, and any new extfree work
      items need to have their own pending event.
      
      While we're at it, hoist the predicate to its own static inline function
      for readability.
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      6b126139
    • Darrick J. Wong's avatar
      xfs: make xchk_iget safer in the presence of corrupt inode btrees · 3f113c27
      Darrick J. Wong authored
      When scrub is trying to iget an inode, ensure that it won't end up
      deadlocked on a cycle in the inode btree by using an empty transaction
      to store all the buffers.
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      3f113c27
    • Darrick J. Wong's avatar
      xfs: elide ->create_done calls for unlogged deferred work · 9c07bca7
      Darrick J. Wong authored
      Extended attribute updates use the deferred work machinery to manage
      state across a chain of smaller transactions.  All previous deferred
      work users have employed log intent items and log done items to manage
      restarting of interrupted operations, which means that ->create_intent
      sets dfp_intent to a log intent item and ->create_done uses that item to
      create a log intent done item.
      
      However, xattrs have used the INCOMPLETE flag to deal with the lack of
      recovery support for an interrupted transaction chain.  Log items are
      optional if the xattr update caller didn't set XFS_DA_OP_LOGGED to
      require a restartable sequence.
      
      In other words, ->create_intent can return NULL to say that there's no
      log intent item.  If that's the case, no log intent done item should be
      created.  Clean up xfs_defer_create_done not to do this, so that the
      ->create_done functions don't have to check for non-null dfp_intent
      themselves.
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      9c07bca7
    • Darrick J. Wong's avatar
      xfs: don't allow overly small or large realtime volumes · e1429380
      Darrick J. Wong authored
      Don't allow realtime volumes that are less than one rt extent long.
      This has been broken across 4 LTS kernels with nobody noticing, so let's
      just disable it.
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      e1429380
    • Darrick J. Wong's avatar
      xfs: move ->iop_relog to struct xfs_defer_op_type · a49c708f
      Darrick J. Wong authored
      The only log items that need relogging are the ones created for deferred
      work operations, and the only part of the code base that relogs log
      items is the deferred work machinery.  Move the function pointers.
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      a49c708f
    • Darrick J. Wong's avatar
      xfs: document what LARP means · 94da54d5
      Darrick J. Wong authored
      Christoph requested a blurb somewhere explaining exactly what LARP
      means.  I don't know of a good place other than the source code (debug
      knobs aren't covered in Documentation/), so here it is.
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      94da54d5
    • Darrick J. Wong's avatar
      xfs: fix 32-bit truncation in xfs_compute_rextslog · cf8f0e6c
      Darrick J. Wong authored
      It's quite reasonable that some customer somewhere will want to
      configure a realtime volume with more than 2^32 extents.  If they try to
      do this, the highbit32() call will truncate the upper bits of the
      xfs_rtbxlen_t and produce the wrong value for rextslog.  This in turn
      causes the rsumlevels to be wrong, which results in a realtime summary
      file that is the wrong length.  Fix that.
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      cf8f0e6c
    • Darrick J. Wong's avatar
      xfs: make rextslog computation consistent with mkfs · a6a38f30
      Darrick J. Wong authored
      There's a weird discrepancy in xfsprogs dating back to the creation of
      the Linux port -- if there are zero rt extents, mkfs will set
      sb_rextents and sb_rextslog both to zero:
      
      	sbp->sb_rextslog =
      		(uint8_t)(rtextents ?
      			libxfs_highbit32((unsigned int)rtextents) : 0);
      
      However, that's not the check that xfs_repair uses for nonzero rtblocks:
      
      	if (sb->sb_rextslog !=
      			libxfs_highbit32((unsigned int)sb->sb_rextents))
      
      The difference here is that xfs_highbit32 returns -1 if its argument is
      zero.  Unfortunately, this means that in the weird corner case of a
      realtime volume shorter than 1 rt extent, xfs_repair will immediately
      flag a freshly formatted filesystem as corrupt.  Because mkfs has been
      writing ondisk artifacts like this for decades, we have to accept that
      as "correct".  TBH, zero rextslog for zero rtextents makes more sense to
      me anyway.
      
      Regrettably, the superblock verifier checks created in commit copied
      xfs_repair even though mkfs has been writing out such filesystems for
      ages.  Fix the superblock verifier to accept what mkfs spits out; the
      userspace version of this patch will have to fix xfs_repair as well.
      
      Note that the new helper leaves the zeroday bug where the upper 32 bits
      of sb_rextents is ripped off and fed to highbit32.  This leads to a
      seriously undersized rt summary file, which immediately breaks mkfs:
      
      $ hugedisk.sh foo /dev/sdc $(( 0x100000080 * 4096))B
      $ /sbin/mkfs.xfs -f /dev/sda -m rmapbt=0,reflink=0 -r rtdev=/dev/mapper/foo
      meta-data=/dev/sda               isize=512    agcount=4, agsize=1298176 blks
               =                       sectsz=512   attr=2, projid32bit=1
               =                       crc=1        finobt=1, sparse=1, rmapbt=0
               =                       reflink=0    bigtime=1 inobtcount=1 nrext64=1
      data     =                       bsize=4096   blocks=5192704, imaxpct=25
               =                       sunit=0      swidth=0 blks
      naming   =version 2              bsize=4096   ascii-ci=0, ftype=1
      log      =internal log           bsize=4096   blocks=16384, version=2
               =                       sectsz=512   sunit=0 blks, lazy-count=1
      realtime =/dev/mapper/foo        extsz=4096   blocks=4294967424, rtextents=4294967424
      Discarding blocks...Done.
      mkfs.xfs: Error initializing the realtime space [117 - Structure needs cleaning]
      
      The next patch will drop support for rt volumes with fewer than 1 or
      more than 2^32-1 rt extents, since they've clearly been broken forever.
      
      Fixes: f8e566c0 ("xfs: validate the realtime geometry in xfs_validate_sb_common")
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      a6a38f30
    • Darrick J. Wong's avatar
      xfs: collapse the ->create_done functions · 8a9aa763
      Darrick J. Wong authored
      Move the meat of the ->create_done function helpers into ->create_done
      to reduce the amount of boilerplate.
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      8a9aa763
    • Darrick J. Wong's avatar
      xfs: hoist xfs_trans_add_item calls to defer ops functions · b28852a5
      Darrick J. Wong authored
      Remove even more repeated boilerplate.
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      b28852a5
    • Darrick J. Wong's avatar
      xfs: clean out XFS_LI_DIRTY setting boilerplate from ->iop_relog · 3e0958be
      Darrick J. Wong authored
      Hoist this dirty flag setting to the ->iop_relog callsite to reduce
      boilerplate.
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      3e0958be
    • Darrick J. Wong's avatar
      xfs: use xfs_defer_create_done for the relogging operation · bd3a88f6
      Darrick J. Wong authored
      Now that we have a helper to handle creating a log intent done item and
      updating all the necessary state flags, use it to reduce boilerplate in
      the ->iop_relog implementations.
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      bd3a88f6
    • Darrick J. Wong's avatar
      xfs: hoist ->create_intent boilerplate to its callsite · f3fd7f6f
      Darrick J. Wong authored
      Hoist the dirty flag setting code out of each ->create_intent
      implementation up to the callsite to reduce boilerplate further.
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      f3fd7f6f
    • Darrick J. Wong's avatar
      xfs: collapse the ->finish_item helpers · e6e5299f
      Darrick J. Wong authored
      Each log item's ->finish_item function sets up a small amount of state
      and calls another function to do the work.  Collapse that other function
      into ->finish_item to reduce the call stack height.
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      e6e5299f
    • Darrick J. Wong's avatar
      xfs: move ->iop_recover to xfs_defer_op_type · db7ccc0b
      Darrick J. Wong authored
      Finish off the series by moving the intent item recovery function
      pointer to the xfs_defer_op_type struct, since this is really a deferred
      work function now.
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      db7ccc0b
    • Darrick J. Wong's avatar
      xfs: hoist intent done flag setting to ->finish_item callsite · 3dd75c8d
      Darrick J. Wong authored
      Each log intent item's ->finish_item call chain inevitably includes some
      code to set the dirty flag of the transaction.  If there's an associated
      log intent done item, it also sets the item's dirty flag and the
      transaction's INTENT_DONE flag.  This is repeated throughout the
      codebase.
      
      Reduce the LOC by moving all that to xfs_defer_finish_one.
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      3dd75c8d
    • Darrick J. Wong's avatar
      xfs: use xfs_defer_finish_one to finish recovered work items · e5f1a514
      Darrick J. Wong authored
      Get rid of the open-coded calls to xfs_defer_finish_one.  This also
      means that the recovery transaction takes care of cleaning up the dfp,
      and we have solved (I hope) all the ownership issues in recovery.
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      e5f1a514
    • Darrick J. Wong's avatar
      xfs: don't set XFS_TRANS_HAS_INTENT_DONE when there's no ATTRD log item · 172538be
      Darrick J. Wong authored
      XFS_TRANS_HAS_INTENT_DONE is a flag to the CIL that we've added a log
      intent done item to the transaction.  This enables an optimization
      wherein we avoid writing out log intent and log intent done items if
      they would have ended up in the same checkpoint.  This reduces writes to
      the ondisk log and speeds up recovery as a result.
      
      However, callers can use the defer ops machinery to modify xattrs
      without using the log items.  In this situation, there won't be an
      intent done item, so we do not need to set the flag.
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      172538be
    • Darrick J. Wong's avatar
      xfs: dump the recovered xattri log item if corruption happens · a51489e1
      Darrick J. Wong authored
      If xfs_attri_item_recover receives a corruption error when it tries to
      finish a recovered log intent item, it should dump the log item for
      debugging, just like all the other log intent items.
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      a51489e1