Pull btrfs fix from Chris Mason:
"Sage hit a deadlock with ceph on btrfs, and Josef tracked it down to a
regression in our initial rc1 pull. When doing nocow writes we were
sometimes starting a transaction with locks held"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
Btrfs: release path before starting transaction in can_nocow_extent