Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable

* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
  Btrfs: apply updated fallocate i_size fix
  Btrfs: do not try and lookup the file extent when finishing ordered io
  Btrfs: Fix oopsen when dropping empty tree.
  Btrfs: remove BUG_ON() due to mounting bad filesystem
  Btrfs: make error return negative in btrfs_sync_file()
  Btrfs: fix race between allocate and release extent buffer.