Btrfs: check UUID tree during mount if required
If the filesystem was mounted with an old kernel that was not aware of the UUID tree, this is detected by looking at the uuid_tree_generation field of the superblock (similar to how the free space cache is doing it). If a mismatch is detected at mount time, a thread is started that does two things: 1. Iterate through the UUID tree, check each entry, delete those entries that are not valid anymore (i.e., the subvol does not exist anymore or the value changed). 2. Iterate through the root tree, for each found subvolume, add the UUID tree entries for the subvolume (if they are not already there). This mechanism is also used to handle and repair errors that happened during the initial creation and filling of the tree. The update of the uuid_tree_generation field (which indicates that the state of the UUID tree is up to date) is blocked until all create and repair operations are successfully completed. Signed-off-by:Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by:
Josef Bacik <jbacik@fusionio.com> Signed-off-by:
Chris Mason <chris.mason@fusionio.com>
parent
26432799
Please register or sign in to comment