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authorAnand Jain <anand.jain@oracle.com>2023-05-24 20:02:38 +0800
committerDavid Sterba <dsterba@suse.com>2023-06-19 13:59:29 +0200
commitf62c302e6dfe7bb03b35157e1c1b7cdaeabd54f9 (patch)
treebfe6476ed084391b4fc3f81b3682dccf69229491 /fs/btrfs/volumes.h
parentc6930d7d11e30f55dee1e306bc3a3105fde56f93 (diff)
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btrfs: add comment about metadata_uuid in btrfs_fs_devices
Add comment about metadata_uuid in btrfs_fs_devices. No functional change. Signed-off-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/volumes.h')
-rw-r--r--fs/btrfs/volumes.h12
1 files changed, 12 insertions, 0 deletions
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 236ae696c984..24f30542ef7c 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -280,7 +280,19 @@ enum btrfs_read_policy {
struct btrfs_fs_devices {
u8 fsid[BTRFS_FSID_SIZE]; /* FS specific uuid */
+
+ /*
+ * UUID written into the btree blocks:
+ *
+ * - If metadata_uuid != fsid then super block must have
+ * BTRFS_FEATURE_INCOMPAT_METADATA_UUID flag set.
+ *
+ * - Following shall be true at all times:
+ * - metadata_uuid == btrfs_header::fsid
+ * - metadata_uuid == btrfs_dev_item::fsid
+ */
u8 metadata_uuid[BTRFS_FSID_SIZE];
+
struct list_head fs_list;
/*