• Qu Wenruo's avatar
    btrfs: Use real device structure to verify dev extent · 1b3922a8
    Qu Wenruo authored
    [BUG]
    Linux v5.0-rc1 will fail fstests/btrfs/163 with the following kernel
    message:
    
      BTRFS error (device dm-6): dev extent devid 1 physical offset 13631488 len 8388608 is beyond device boundary 0
      BTRFS error (device dm-6): failed to verify dev extents against chunks: -117
      BTRFS error (device dm-6): open_ctree failed
    
    [CAUSE]
    Commit cf90d884 ("btrfs: Introduce mount time chunk <-> dev extent
    mapping check") introduced strict check on dev extents.
    
    We use btrfs_find_device() with dev uuid and fs uuid set to NULL, and
    only dependent on @devid to find the real device.
    
    For seed devices, we call clone_fs_devices() in open_seed_devices() to
    allow us search seed devices directly.
    
    However clone_fs_devices() just populates devices with devid and dev
    uuid, without populating other essential members, like disk_total_bytes.
    
    This makes any device returned by btrfs_find_device(fs_info, devid,
    NULL, NULL) is just a dummy, with 0 disk_total_bytes, and any dev
    extents on the seed device will not pass the device boundary check.
    
    [FIX]
    This patch will try to verify the device returned by btrfs_find_device()
    and if it's a dummy then re-search in seed devices.
    
    Fixes: cf90d884 ("btrfs: Introduce mount time chunk <-> dev extent mapping check")
    CC: stable@vger.kernel.org # 4.19+
    Reported-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>
    1b3922a8
volumes.c 210 KB