Test btrfs quota group consistency operations during snapshot
delete. Btrfs has had long standing issues with drop snapshot
failing to properly account for quota groups. This test crafts
several snapshot trees with shared and exclusive elements. One of
the trees is removed and then quota group consistency is checked.
This issue is fixed by the following linux kernel patches:
Btrfs: use btrfs_get_fs_root in resolve_indirect_ref
Btrfs: keep dropped roots in cache until transaciton commit
btrfs: qgroup: account shared subtree during snapshot delete
Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>