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| author | Anand Jain <anand.jain@oracle.com> | 2023-09-06 19:16:41 +0300 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2023-10-12 17:44:04 +0300 |
| commit | cb6eb4757e1ea7867bcfe4b8a8b6199cc803b8c2 (patch) | |
| tree | b2b58187b5183d6e58e3751bbf44987418cddce1 /fs | |
| parent | 1246873114cf6e4cfbd9530ba70911f6c802510d (diff) | |
| download | linux-cb6eb4757e1ea7867bcfe4b8a8b6199cc803b8c2.tar.xz | |
btrfs: comment about fsid and metadata_uuid relationship
Add a comment explaining the relationship between fsid and metadata_uuid
in the on-disk superblock and the in-memory struct btrfs_fs_devices.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/volumes.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h index 2128a032c3b7..576bfcb5b764 100644 --- a/fs/btrfs/volumes.h +++ b/fs/btrfs/volumes.h @@ -290,6 +290,15 @@ struct btrfs_fs_devices { * - Following shall be true at all times: * - metadata_uuid == btrfs_header::fsid * - metadata_uuid == btrfs_dev_item::fsid + * + * - Relations between fsid and metadata_uuid in sb and fs_devices: + * - Normal: + * fs_devices->fsid == fs_devices->metadata_uuid == sb->fsid + * sb->metadata_uuid == 0 + * + * - When the BTRFS_FEATURE_INCOMPAT_METADATA_UUID flag is set: + * fs_devices->fsid == sb->fsid + * fs_devices->metadata_uuid == sb->metadata_uuid */ u8 metadata_uuid[BTRFS_FSID_SIZE]; |