1. 19 Apr, 2022 1 commit
  2. 05 Apr, 2022 9 commits
  3. 24 Mar, 2022 5 commits
    • Kaiwen Hu's avatar
      btrfs: prevent subvol with swapfile from being deleted · 60021bd7
      Kaiwen Hu authored
      A subvolume with an active swapfile must not be deleted otherwise it
      would not be possible to deactivate it.
      
      After the subvolume is deleted, we cannot swapoff the swapfile in this
      deleted subvolume because the path is unreachable.  The swapfile is
      still active and holding references, the filesystem cannot be unmounted.
      
      The test looks like this:
      
        mkfs.btrfs -f $dev > /dev/null
        mount $dev $mnt
      
        btrfs sub create $mnt/subvol
        touch $mnt/subvol/swapfile
        chmod 600 $mnt/subvol/swapfile
        chattr +C $mnt/subvol/swapfile
        dd if=/dev/zero of=$mnt/subvol/swapfile bs=1K count=4096
        mkswap $mnt/subvol/swapfile
        swapon $mnt/subvol/swapfile
      
        btrfs sub delete $mnt/subvol
        swapoff $mnt/subvol/swapfile  # failed: No such file or directory
        swapoff --all
      
        unmount $mnt                  # target is busy.
      
      To prevent above issue, we simply check that whether the subvolume
      contains any active swapfile, and stop the deleting process.  This
      behavior is like snapshot ioctl dealing with a swapfile.
      
      CC: stable@vger.kernel.org # 5.4+
      Reviewed-by: default avatarRobbie Ko <robbieko@synology.com>
      Reviewed-by: default avatarQu Wenruo <wqu@suse.com>
      Reviewed-by: default avatarFilipe Manana <fdmanana@suse.com>
      Signed-off-by: default avatarKaiwen Hu <kevinhu@synology.com>
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      60021bd7
    • Josef Bacik's avatar
      btrfs: do not warn for free space inode in cow_file_range · a7d16d9a
      Josef Bacik authored
      This is a long time leftover from when I originally added the free space
      inode, the point was to catch cases where we weren't honoring the NOCOW
      flag.  However there exists a race with relocation, if we allocate our
      free space inode in a block group that is about to be relocated, we
      could trigger the COW path before the relocation has the opportunity to
      find the extents and delete the free space cache.  In production where
      we have auto-relocation enabled we're seeing this WARN_ON_ONCE() around
      5k times in a 2 week period, so not super common but enough that it's at
      the top of our metrics.
      
      We're properly handling the error here, and with us phasing out v1 space
      cache anyway just drop the WARN_ON_ONCE.
      Signed-off-by: default avatarJosef Bacik <josef@toxicpanda.com>
      Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      a7d16d9a
    • Qu Wenruo's avatar
      btrfs: avoid defragging extents whose next extents are not targets · 75a36a7d
      Qu Wenruo authored
      [BUG]
      There is a report that autodefrag is defragging single sector, which
      is completely waste of IO, and no help for defragging:
      
         btrfs-cleaner-808 defrag_one_locked_range: root=256 ino=651122 start=0 len=4096
      
      [CAUSE]
      In defrag_collect_targets(), we check if the current range (A) can be merged
      with next one (B).
      
      If mergeable, we will add range A into target for defrag.
      
      However there is a catch for autodefrag, when checking mergeability
      against range B, we intentionally pass 0 as @newer_than, hoping to get a
      higher chance to merge with the next extent.
      
      But in the next iteration, range B will looked up by defrag_lookup_extent(),
      with non-zero @newer_than.
      
      And if range B is not really newer, it will rejected directly, causing
      only range A being defragged, while we expect to defrag both range A and
      B.
      
      [FIX]
      Since the root cause is the difference in check condition of
      defrag_check_next_extent() and defrag_collect_targets(), we fix it by:
      
      1. Pass @newer_than to defrag_check_next_extent()
      2. Pass @extent_thresh to defrag_check_next_extent()
      
      This makes the check between defrag_collect_targets() and
      defrag_check_next_extent() more consistent.
      
      While there is still some minor difference, the remaining checks are
      focus on runtime flags like writeback/delalloc, which are mostly
      transient and safe to be checked only in defrag_collect_targets().
      
      Link: https://github.com/btrfs/linux/issues/423#issuecomment-1066981856
      CC: stable@vger.kernel.org # 5.16+
      Reviewed-by: default avatarFilipe Manana <fdmanana@suse.com>
      Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      75a36a7d
    • Darrick J. Wong's avatar
      btrfs: fix fallocate to use file_modified to update permissions consistently · 05fd9564
      Darrick J. Wong authored
      Since the initial introduction of (posix) fallocate back at the turn of
      the century, it has been possible to use this syscall to change the
      user-visible contents of files.  This can happen by extending the file
      size during a preallocation, or through any of the newer modes (punch,
      zero range).  Because the call can be used to change file contents, we
      should treat it like we do any other modification to a file -- update
      the mtime, and drop set[ug]id privileges/capabilities.
      
      The VFS function file_modified() does all this for us if pass it a
      locked inode, so let's make fallocate drop permissions correctly.
      Reviewed-by: default avatarFilipe Manana <fdmanana@suse.com>
      Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      05fd9564
    • Qu Wenruo's avatar
      btrfs: remove device item and update super block in the same transaction · bbac5869
      Qu Wenruo authored
      [BUG]
      There is a report that a btrfs has a bad super block num devices.
      
      This makes btrfs to reject the fs completely.
      
        BTRFS error (device sdd3): super_num_devices 3 mismatch with num_devices 2 found here
        BTRFS error (device sdd3): failed to read chunk tree: -22
        BTRFS error (device sdd3): open_ctree failed
      
      [CAUSE]
      During btrfs device removal, chunk tree and super block num devs are
      updated in two different transactions:
      
        btrfs_rm_device()
        |- btrfs_rm_dev_item(device)
        |  |- trans = btrfs_start_transaction()
        |  |  Now we got transaction X
        |  |
        |  |- btrfs_del_item()
        |  |  Now device item is removed from chunk tree
        |  |
        |  |- btrfs_commit_transaction()
        |     Transaction X got committed, super num devs untouched,
        |     but device item removed from chunk tree.
        |     (AKA, super num devs is already incorrect)
        |
        |- cur_devices->num_devices--;
        |- cur_devices->total_devices--;
        |- btrfs_set_super_num_devices()
           All those operations are not in transaction X, thus it will
           only be written back to disk in next transaction.
      
      So after the transaction X in btrfs_rm_dev_item() committed, but before
      transaction X+1 (which can be minutes away), a power loss happen, then
      we got the super num mismatch.
      
      [FIX]
      Instead of starting and committing a transaction inside
      btrfs_rm_dev_item(), start a transaction in side btrfs_rm_device() and
      pass it to btrfs_rm_dev_item().
      
      And only commit the transaction after everything is done.
      Reported-by: default avatarLuca Béla Palkovics <luca.bela.palkovics@gmail.com>
      Link: https://lore.kernel.org/linux-btrfs/CA+8xDSpvdm_U0QLBAnrH=zqDq_cWCOH5TiV46CKmp3igr44okQ@mail.gmail.com/
      CC: stable@vger.kernel.org # 4.14+
      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>
      bbac5869
  4. 23 Mar, 2022 3 commits
    • Ethan Lien's avatar
      btrfs: fix qgroup reserve overflow the qgroup limit · b642b52d
      Ethan Lien authored
      We use extent_changeset->bytes_changed in qgroup_reserve_data() to record
      how many bytes we set for EXTENT_QGROUP_RESERVED state. Currently the
      bytes_changed is set as "unsigned int", and it will overflow if we try to
      fallocate a range larger than 4GiB. The result is we reserve less bytes
      and eventually break the qgroup limit.
      
      Unlike regular buffered/direct write, which we use one changeset for
      each ordered extent, which can never be larger than 256M.  For
      fallocate, we use one changeset for the whole range, thus it no longer
      respects the 256M per extent limit, and caused the problem.
      
      The following example test script reproduces the problem:
      
        $ cat qgroup-overflow.sh
        #!/bin/bash
      
        DEV=/dev/sdj
        MNT=/mnt/sdj
      
        mkfs.btrfs -f $DEV
        mount $DEV $MNT
      
        # Set qgroup limit to 2GiB.
        btrfs quota enable $MNT
        btrfs qgroup limit 2G $MNT
      
        # Try to fallocate a 3GiB file. This should fail.
        echo
        echo "Try to fallocate a 3GiB file..."
        fallocate -l 3G $MNT/3G.file
      
        # Try to fallocate a 5GiB file.
        echo
        echo "Try to fallocate a 5GiB file..."
        fallocate -l 5G $MNT/5G.file
      
        # See we break the qgroup limit.
        echo
        sync
        btrfs qgroup show -r $MNT
      
        umount $MNT
      
      When running the test:
      
        $ ./qgroup-overflow.sh
        (...)
      
        Try to fallocate a 3GiB file...
        fallocate: fallocate failed: Disk quota exceeded
      
        Try to fallocate a 5GiB file...
      
        qgroupid         rfer         excl     max_rfer
        --------         ----         ----     --------
        0/5           5.00GiB      5.00GiB      2.00GiB
      
      Since we have no control of how bytes_changed is used, it's better to
      set it to u64.
      
      CC: stable@vger.kernel.org # 4.14+
      Reviewed-by: default avatarQu Wenruo <wqu@suse.com>
      Signed-off-by: default avatarEthan Lien <ethanlien@synology.com>
      Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      b642b52d
    • Johannes Thumshirn's avatar
      btrfs: zoned: remove left over ASSERT checking for single profile · 62ed0bf7
      Johannes Thumshirn authored
      With commit dcf5652291f6 ("btrfs: zoned: allow DUP on meta-data block
      groups") we started allowing DUP on metadata block groups, so the
      ASSERT()s in btrfs_can_activate_zone() and btrfs_zoned_get_device() are
      no longer valid and in fact even harmful.
      
      Fixes: dcf5652291f6 ("btrfs: zoned: allow DUP on meta-data block groups")
      CC: stable@vger.kernel.org # 5.17
      Signed-off-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
      Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      62ed0bf7
    • Johannes Thumshirn's avatar
      btrfs: zoned: traverse devices under chunk_mutex in btrfs_can_activate_zone · 0b9e6676
      Johannes Thumshirn authored
      btrfs_can_activate_zone() can be called with the device_list_mutex already
      held, which will lead to a deadlock:
      
      insert_dev_extents() // Takes device_list_mutex
      `-> insert_dev_extent()
       `-> btrfs_insert_empty_item()
        `-> btrfs_insert_empty_items()
         `-> btrfs_search_slot()
          `-> btrfs_cow_block()
           `-> __btrfs_cow_block()
            `-> btrfs_alloc_tree_block()
             `-> btrfs_reserve_extent()
              `-> find_free_extent()
               `-> find_free_extent_update_loop()
                `-> can_allocate_chunk()
                 `-> btrfs_can_activate_zone() // Takes device_list_mutex again
      
      Instead of using the RCU on fs_devices->device_list we
      can use fs_devices->alloc_list, protected by the chunk_mutex to traverse
      the list of active devices.
      
      We are in the chunk allocation thread. The newer chunk allocation
      happens from the devices in the fs_device->alloc_list protected by the
      chunk_mutex.
      
        btrfs_create_chunk()
          lockdep_assert_held(&info->chunk_mutex);
          gather_device_info
            list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list)
      
      Also, a device that reappears after the mount won't join the alloc_list
      yet and, it will be in the dev_list, which we don't want to consider in
      the context of the chunk alloc.
      
        [15.166572] WARNING: possible recursive locking detected
        [15.167117] 5.17.0-rc6-dennis #79 Not tainted
        [15.167487] --------------------------------------------
        [15.167733] kworker/u8:3/146 is trying to acquire lock:
        [15.167733] ffff888102962ee0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: find_free_extent+0x15a/0x14f0 [btrfs]
        [15.167733]
        [15.167733] but task is already holding lock:
        [15.167733] ffff888102962ee0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_create_pending_block_groups+0x20a/0x560 [btrfs]
        [15.167733]
        [15.167733] other info that might help us debug this:
        [15.167733]  Possible unsafe locking scenario:
        [15.167733]
        [15.171834]        CPU0
        [15.171834]        ----
        [15.171834]   lock(&fs_devs->device_list_mutex);
        [15.171834]   lock(&fs_devs->device_list_mutex);
        [15.171834]
        [15.171834]  *** DEADLOCK ***
        [15.171834]
        [15.171834]  May be due to missing lock nesting notation
        [15.171834]
        [15.171834] 5 locks held by kworker/u8:3/146:
        [15.171834]  #0: ffff888100050938 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x1c3/0x5a0
        [15.171834]  #1: ffffc9000067be80 ((work_completion)(&fs_info->async_data_reclaim_work)){+.+.}-{0:0}, at: process_one_work+0x1c3/0x5a0
        [15.176244]  #2: ffff88810521e620 (sb_internal){.+.+}-{0:0}, at: flush_space+0x335/0x600 [btrfs]
        [15.176244]  #3: ffff888102962ee0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_create_pending_block_groups+0x20a/0x560 [btrfs]
        [15.176244]  #4: ffff8881152e4b78 (btrfs-dev-00){++++}-{3:3}, at: __btrfs_tree_lock+0x27/0x130 [btrfs]
        [15.179641]
        [15.179641] stack backtrace:
        [15.179641] CPU: 1 PID: 146 Comm: kworker/u8:3 Not tainted 5.17.0-rc6-dennis #79
        [15.179641] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1.fc35 04/01/2014
        [15.179641] Workqueue: events_unbound btrfs_async_reclaim_data_space [btrfs]
        [15.179641] Call Trace:
        [15.179641]  <TASK>
        [15.179641]  dump_stack_lvl+0x45/0x59
        [15.179641]  __lock_acquire.cold+0x217/0x2b2
        [15.179641]  lock_acquire+0xbf/0x2b0
        [15.183838]  ? find_free_extent+0x15a/0x14f0 [btrfs]
        [15.183838]  __mutex_lock+0x8e/0x970
        [15.183838]  ? find_free_extent+0x15a/0x14f0 [btrfs]
        [15.183838]  ? find_free_extent+0x15a/0x14f0 [btrfs]
        [15.183838]  ? lock_is_held_type+0xd7/0x130
        [15.183838]  ? find_free_extent+0x15a/0x14f0 [btrfs]
        [15.183838]  find_free_extent+0x15a/0x14f0 [btrfs]
        [15.183838]  ? _raw_spin_unlock+0x24/0x40
        [15.183838]  ? btrfs_get_alloc_profile+0x106/0x230 [btrfs]
        [15.187601]  btrfs_reserve_extent+0x131/0x260 [btrfs]
        [15.187601]  btrfs_alloc_tree_block+0xb5/0x3b0 [btrfs]
        [15.187601]  __btrfs_cow_block+0x138/0x600 [btrfs]
        [15.187601]  btrfs_cow_block+0x10f/0x230 [btrfs]
        [15.187601]  btrfs_search_slot+0x55f/0xbc0 [btrfs]
        [15.187601]  ? lock_is_held_type+0xd7/0x130
        [15.187601]  btrfs_insert_empty_items+0x2d/0x60 [btrfs]
        [15.187601]  btrfs_create_pending_block_groups+0x2b3/0x560 [btrfs]
        [15.187601]  __btrfs_end_transaction+0x36/0x2a0 [btrfs]
        [15.192037]  flush_space+0x374/0x600 [btrfs]
        [15.192037]  ? find_held_lock+0x2b/0x80
        [15.192037]  ? btrfs_async_reclaim_data_space+0x49/0x180 [btrfs]
        [15.192037]  ? lock_release+0x131/0x2b0
        [15.192037]  btrfs_async_reclaim_data_space+0x70/0x180 [btrfs]
        [15.192037]  process_one_work+0x24c/0x5a0
        [15.192037]  worker_thread+0x4a/0x3d0
      
      Fixes: a85f05e5 ("btrfs: zoned: avoid chunk allocation if active block group has enough space")
      CC: stable@vger.kernel.org # 5.16+
      Reviewed-by: default avatarAnand Jain <anand.jain@oracle.com>
      Signed-off-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
      Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
      Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
      0b9e6676
  5. 14 Mar, 2022 22 commits