1. 08 Mar, 2023 1 commit
    • Filipe Manana's avatar
      btrfs: fix block group item corruption after inserting new block group · 675dfe12
      Filipe Manana authored
      We can often end up inserting a block group item, for a new block group,
      with a wrong value for the used bytes field.
      
      This happens if for the new allocated block group, in the same transaction
      that created the block group, we have tasks allocating extents from it as
      well as tasks removing extents from it.
      
      For example:
      
      1) Task A creates a metadata block group X;
      
      2) Two extents are allocated from block group X, so its "used" field is
         updated to 32K, and its "commit_used" field remains as 0;
      
      3) Transaction commit starts, by some task B, and it enters
         btrfs_start_dirty_block_groups(). There it tries to update the block
         group item for block group X, which currently has its "used" field with
         a value of 32K. But that fails since the block group item was not yet
         inserted, and so on failure update_block_group_item() sets the
         "commit_used" field of the block group back to 0;
      
      4) The block group item is inserted by task A, when for example
         btrfs_create_pending_block_groups() is called when releasing its
         transaction handle. This results in insert_block_group_item() inserting
         the block group item in the extent tree (or block group tree), with a
         "used" field having a value of 32K, but without updating the
         "commit_used" field in the block group, which remains with value of 0;
      
      5) The two extents are freed from block X, so its "used" field changes
         from 32K to 0;
      
      6) The transaction commit by task B continues, it enters
         btrfs_write_dirty_block_groups() which calls update_block_group_item()
         for block group X, and there it decides to skip the block group item
         update, because "used" has a value of 0 and "commit_used" has a value
         of 0 too.
      
         As a result, we end up with a block item having a 32K "used" field but
         no extents allocated from it.
      
      When this issue happens, a btrfs check reports an error like this:
      
         [1/7] checking root items
         [2/7] checking extents
         block group [1104150528 1073741824] used 39796736 but extent items used 0
         ERROR: errors found in extent allocation tree or chunk allocation
         (...)
      
      Fix this by making insert_block_group_item() update the block group's
      "commit_used" field.
      
      Fixes: 7248e0ce ("btrfs: skip update of block group item if used bytes are the same")
      CC: stable@vger.kernel.org # 6.2+
      Reviewed-by: default avatarQu Wenruo <wqu@suse.com>
      Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      675dfe12
  2. 06 Mar, 2023 6 commits
    • Filipe Manana's avatar
      btrfs: fix extent map logging bit not cleared for split maps after dropping range · e4cc1483
      Filipe Manana authored
      At btrfs_drop_extent_map_range() we are clearing the EXTENT_FLAG_LOGGING
      bit on a 'flags' variable that was not initialized. This makes static
      checkers complain about it, so initialize the 'flags' variable before
      clearing the bit.
      
      In practice this has no consequences, because EXTENT_FLAG_LOGGING should
      not be set when btrfs_drop_extent_map_range() is called, as an fsync locks
      the inode in exclusive mode, locks the inode's mmap semaphore in exclusive
      mode too and it always flushes all delalloc.
      
      Also add a comment about why we clear EXTENT_FLAG_LOGGING on a copy of the
      flags of the split extent map.
      Reported-by: default avatarDan Carpenter <error27@gmail.com>
      Link: https://lore.kernel.org/linux-btrfs/Y%2FyipSVozUDEZKow@kili/
      Fixes: db21370b ("btrfs: drop extent map range more efficiently")
      Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      e4cc1483
    • Johannes Thumshirn's avatar
      btrfs: fix percent calculation for bg reclaim message · 95cd356c
      Johannes Thumshirn authored
      We have a report, that the info message for block-group reclaim is
      crossing the 100% used mark.
      
      This is happening as we were truncating the divisor for the division
      (the block_group->length) to a 32bit value.
      
      Fix this by using div64_u64() to not truncate the divisor.
      
      In the worst case, it can lead to a div by zero error and should be
      possible to trigger on 4 disks RAID0, and each device is large enough:
      
        $ mkfs.btrfs  -f /dev/test/scratch[1234] -m raid1 -d raid0
        btrfs-progs v6.1
        [...]
        Filesystem size:    40.00GiB
        Block group profiles:
          Data:             RAID0             4.00GiB <<<
          Metadata:         RAID1           256.00MiB
          System:           RAID1             8.00MiB
      Reported-by: default avatarForza <forza@tnonline.net>
      Link: https://lore.kernel.org/linux-btrfs/e99483.c11a58d.1863591ca52@tnonline.net/
      Fixes: 5f93e776 ("btrfs: zoned: print unusable percentage when reclaiming block groups")
      CC: stable@vger.kernel.org # 5.15+
      Reviewed-by: default avatarAnand Jain <anand.jain@oracle.com>
      Reviewed-by: default avatarQu Wenruo <wqu@suse.com>
      Signed-off-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
      Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
      [ add Qu's note ]
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      95cd356c
    • Naohiro Aota's avatar
      btrfs: fix unnecessary increment of read error stat on write error · 98e8d36a
      Naohiro Aota authored
      Current btrfs_log_dev_io_error() increases the read error count even if the
      erroneous IO is a WRITE request. This is because it forget to use "else
      if", and all the error WRITE requests counts as READ error as there is (of
      course) no REQ_RAHEAD bit set.
      
      Fixes: c3a62baf ("btrfs: use chained bios when cloning")
      CC: stable@vger.kernel.org # 6.1+
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
      Signed-off-by: default avatarNaohiro Aota <naohiro.aota@wdc.com>
      Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      98e8d36a
    • void0red's avatar
      btrfs: handle btrfs_del_item errors in __btrfs_update_delayed_inode · c06016a0
      void0red authored
      Even if the slot is already read out, we may still need to re-balance
      the tree, thus it can cause error in that btrfs_del_item() call and we
      need to handle it properly.
      Reviewed-by: default avatarQu Wenruo <wqu@suse.com>
      Signed-off-by: default avatarvoid0red <void0red@gmail.com>
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      c06016a0
    • Qu Wenruo's avatar
      btrfs: ioctl: return device fsid from DEV_INFO ioctl · 2943868a
      Qu Wenruo authored
      Currently user space utilizes dev info ioctl to grab the info of a
      certain devid, this includes its device uuid.  But the returned info is
      not enough to determine if a device is a seed.
      
      Commit a26d60de ("btrfs: sysfs: add devinfo/fsid to retrieve actual
      fsid from the device") exports the same value in sysfs so this is for
      parity with ioctl.  Add a new member, fsid, into
      btrfs_ioctl_dev_info_args, and populate the member with fsid value.
      
      This should not cause any compatibility problem, following the
      combinations:
      
      - Old user space, old kernel
      - Old user space, new kernel
        User space tool won't even check the new member.
      
      - New user space, old kernel
        The kernel won't touch the new member, and user space tool should
        zero out its argument, thus the new member is all zero.
      
        User space tool can then know the kernel doesn't support this fsid
        reporting, and falls back to whatever they can.
      
      - New user space, new kernel
        Go as planned.
      
        Would find the fsid member is no longer zero, and trust its value.
      Reviewed-by: default avatarAnand Jain <anand.jain@oracle.com>
      Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      2943868a
    • Boris Burkov's avatar
      btrfs: fix potential dead lock in size class loading logic · 12148367
      Boris Burkov authored
      As reported by Filipe, there's a potential deadlock caused by
      using btrfs_search_forward on commit_root. The locking there is
      unconditional, even if ->skip_locking and ->search_commit_root is set.
      It's not meant to be used for commit roots, so it always needs to do
      locking.
      
      So if another task is COWing a child node of the same root node and
      then needs to wait for block group caching to complete when trying to
      allocate a metadata extent, it deadlocks.
      
      For example:
      
      [539604.239315] sysrq: Show Blocked State
      [539604.240133] task:kworker/u16:6   state:D stack:0     pid:2119594 ppid:2      flags:0x00004000
      [539604.241613] Workqueue: btrfs-cache btrfs_work_helper [btrfs]
      [539604.242673] Call Trace:
      [539604.243129]  <TASK>
      [539604.243925]  __schedule+0x41d/0xee0
      [539604.244797]  ? rcu_read_lock_sched_held+0x12/0x70
      [539604.245399]  ? rwsem_down_read_slowpath+0x185/0x490
      [539604.246111]  schedule+0x5d/0xf0
      [539604.246593]  rwsem_down_read_slowpath+0x2da/0x490
      [539604.247290]  ? rcu_barrier_tasks_trace+0x10/0x20
      [539604.248090]  __down_read_common+0x3d/0x150
      [539604.248702]  down_read_nested+0xc3/0x140
      [539604.249280]  __btrfs_tree_read_lock+0x24/0x100 [btrfs]
      [539604.250097]  btrfs_read_lock_root_node+0x48/0x60 [btrfs]
      [539604.250915]  btrfs_search_forward+0x59/0x460 [btrfs]
      [539604.251781]  ? btrfs_global_root+0x50/0x70 [btrfs]
      [539604.252476]  caching_thread+0x1be/0x920 [btrfs]
      [539604.253167]  btrfs_work_helper+0xf6/0x400 [btrfs]
      [539604.253848]  process_one_work+0x24f/0x5a0
      [539604.254476]  worker_thread+0x52/0x3b0
      [539604.255166]  ? __pfx_worker_thread+0x10/0x10
      [539604.256047]  kthread+0xf0/0x120
      [539604.256591]  ? __pfx_kthread+0x10/0x10
      [539604.257212]  ret_from_fork+0x29/0x50
      [539604.257822]  </TASK>
      [539604.258233] task:btrfs-transacti state:D stack:0     pid:2236474 ppid:2      flags:0x00004000
      [539604.259802] Call Trace:
      [539604.260243]  <TASK>
      [539604.260615]  __schedule+0x41d/0xee0
      [539604.261205]  ? rcu_read_lock_sched_held+0x12/0x70
      [539604.262000]  ? rwsem_down_read_slowpath+0x185/0x490
      [539604.262822]  schedule+0x5d/0xf0
      [539604.263374]  rwsem_down_read_slowpath+0x2da/0x490
      [539604.266228]  ? lock_acquire+0x160/0x310
      [539604.266917]  ? rcu_read_lock_sched_held+0x12/0x70
      [539604.267996]  ? lock_contended+0x19e/0x500
      [539604.268720]  __down_read_common+0x3d/0x150
      [539604.269400]  down_read_nested+0xc3/0x140
      [539604.270057]  __btrfs_tree_read_lock+0x24/0x100 [btrfs]
      [539604.271129]  btrfs_read_lock_root_node+0x48/0x60 [btrfs]
      [539604.272372]  btrfs_search_slot+0x143/0xf70 [btrfs]
      [539604.273295]  update_block_group_item+0x9e/0x190 [btrfs]
      [539604.274282]  btrfs_start_dirty_block_groups+0x1c4/0x4f0 [btrfs]
      [539604.275381]  ? __mutex_unlock_slowpath+0x45/0x280
      [539604.276390]  btrfs_commit_transaction+0xee/0xed0 [btrfs]
      [539604.277391]  ? lock_acquire+0x1a4/0x310
      [539604.278080]  ? start_transaction+0xcb/0x6c0 [btrfs]
      [539604.279099]  transaction_kthread+0x142/0x1c0 [btrfs]
      [539604.279996]  ? __pfx_transaction_kthread+0x10/0x10 [btrfs]
      [539604.280673]  kthread+0xf0/0x120
      [539604.281050]  ? __pfx_kthread+0x10/0x10
      [539604.281496]  ret_from_fork+0x29/0x50
      [539604.281966]  </TASK>
      [539604.282255] task:fsstress        state:D stack:0     pid:2236483 ppid:1      flags:0x00004006
      [539604.283897] Call Trace:
      [539604.284700]  <TASK>
      [539604.285088]  __schedule+0x41d/0xee0
      [539604.285660]  schedule+0x5d/0xf0
      [539604.286175]  btrfs_wait_block_group_cache_progress+0xf2/0x170 [btrfs]
      [539604.287342]  ? __pfx_autoremove_wake_function+0x10/0x10
      [539604.288450]  find_free_extent+0xd93/0x1750 [btrfs]
      [539604.289256]  ? _raw_spin_unlock+0x29/0x50
      [539604.289911]  ? btrfs_get_alloc_profile+0x127/0x2a0 [btrfs]
      [539604.290843]  btrfs_reserve_extent+0x147/0x290 [btrfs]
      [539604.291943]  btrfs_alloc_tree_block+0xcb/0x3e0 [btrfs]
      [539604.292903]  __btrfs_cow_block+0x138/0x580 [btrfs]
      [539604.293773]  btrfs_cow_block+0x10e/0x240 [btrfs]
      [539604.294595]  btrfs_search_slot+0x7f3/0xf70 [btrfs]
      [539604.295585]  btrfs_update_device+0x71/0x1b0 [btrfs]
      [539604.296459]  btrfs_chunk_alloc_add_chunk_item+0xe0/0x340 [btrfs]
      [539604.297489]  btrfs_chunk_alloc+0x1bf/0x490 [btrfs]
      [539604.298335]  find_free_extent+0x6fa/0x1750 [btrfs]
      [539604.299174]  ? _raw_spin_unlock+0x29/0x50
      [539604.299950]  ? btrfs_get_alloc_profile+0x127/0x2a0 [btrfs]
      [539604.300918]  btrfs_reserve_extent+0x147/0x290 [btrfs]
      [539604.301797]  btrfs_alloc_tree_block+0xcb/0x3e0 [btrfs]
      [539604.303017]  ? lock_release+0x224/0x4a0
      [539604.303855]  __btrfs_cow_block+0x138/0x580 [btrfs]
      [539604.304789]  btrfs_cow_block+0x10e/0x240 [btrfs]
      [539604.305611]  btrfs_search_slot+0x7f3/0xf70 [btrfs]
      [539604.306682]  ? btrfs_global_root+0x50/0x70 [btrfs]
      [539604.308198]  lookup_inline_extent_backref+0x17b/0x7a0 [btrfs]
      [539604.309254]  lookup_extent_backref+0x43/0xd0 [btrfs]
      [539604.310122]  __btrfs_free_extent+0xf8/0x810 [btrfs]
      [539604.310874]  ? lock_release+0x224/0x4a0
      [539604.311724]  ? btrfs_merge_delayed_refs+0x17b/0x1d0 [btrfs]
      [539604.313023]  __btrfs_run_delayed_refs+0x2ba/0x1260 [btrfs]
      [539604.314271]  btrfs_run_delayed_refs+0x8f/0x1c0 [btrfs]
      [539604.315445]  ? rcu_read_lock_sched_held+0x12/0x70
      [539604.316706]  btrfs_commit_transaction+0xa2/0xed0 [btrfs]
      [539604.317855]  ? do_raw_spin_unlock+0x4b/0xa0
      [539604.318544]  ? _raw_spin_unlock+0x29/0x50
      [539604.319240]  create_subvol+0x53d/0x6e0 [btrfs]
      [539604.320283]  btrfs_mksubvol+0x4f5/0x590 [btrfs]
      [539604.321220]  __btrfs_ioctl_snap_create+0x11b/0x180 [btrfs]
      [539604.322307]  btrfs_ioctl_snap_create_v2+0xc6/0x150 [btrfs]
      [539604.323295]  btrfs_ioctl+0x9f7/0x33e0 [btrfs]
      [539604.324331]  ? rcu_read_lock_sched_held+0x12/0x70
      [539604.325137]  ? lock_release+0x224/0x4a0
      [539604.325808]  ? __x64_sys_ioctl+0x87/0xc0
      [539604.326467]  __x64_sys_ioctl+0x87/0xc0
      [539604.327109]  do_syscall_64+0x38/0x90
      [539604.327875]  entry_SYSCALL_64_after_hwframe+0x72/0xdc
      [539604.328792] RIP: 0033:0x7f05a7babaeb
      
      This needs to use regular btrfs_search_slot() with some skip and stop
      logic.
      
      Since we only consider five samples (five search slots), don't bother
      with the complexity of looking for commit_root_sem contention. If
      necessary, it can be added to the load function in between samples.
      Reported-by: default avatarFilipe Manana <fdmanana@kernel.org>
      Link: https://lore.kernel.org/linux-btrfs/CAL3q7H7eKMD44Z1+=Kb-1RFMMeZpAm2fwyO59yeBwCcSOU80Pg@mail.gmail.com/
      Fixes: c7eec3d9 ("btrfs: load block group size class when caching")
      Signed-off-by: default avatarBoris Burkov <boris@bur.io>
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      12148367
  3. 01 Mar, 2023 1 commit
  4. 15 Feb, 2023 32 commits