Currently mkfs uses its own create_uuid_tree(), but that function is
only handling FS_TREE. This means for btrfs-convert we do not generate
the uuid tree, nor add the UUID of the image subvolume. This can be a
problem if we're going to support multiple subvolumes during mkfs time.
To address this, introduce a new helper, btrfs_rebuild_uuid_tree():
- Create a new uuid tree if there is not one
- Remove all the existing items from uuid tree
- Iterate through all subvolumes
* If the subvolume has no valid UUID, regenerate one
* Add the uuid entry for the subvolume UUID
* If the subvolume has received UUID, also add it to UUID tree
By this, this new helper can handle all the uuid tree generation needs for:
- Current mkfs
Only one uuid entry for FS_TREE
- Current btrfs-convert
Only FS_TREE and the image subvolume
- Future multi-subvolume mkfs
As we do the scan for all subvolumes.
- Future "btrfs rescue rebuild-uuid-tree"
Signed-off-by: Qu Wenruo <wqu@suse.com>
d3cf350e21