• Chris Mason's avatar
    Btrfs: Use mutex_lock_nested for tree locking · 6dddcbeb
    Chris Mason authored
    Lockdep has the notion of locking subclasses so that you can identify
    locks you expect to be taken after other locks of the same class.  This
    changes the per-extent buffer btree locking routines to use a subclass based
    on the level in the tree.
    Unfortunately, lockdep can only handle 8 total subclasses, and the btrfs
    max level is also 8.  So when lockdep is on, use a lower max level.
    Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>