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

Merge git://git./linux/kernel/git/mason/btrfs-unstable

* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (22 commits)
  Btrfs: Fix async caching interaction with unmount
  Btrfs: change how we unpin extents
  Btrfs: Correct redundant test in add_inode_ref
  Btrfs: find smallest available device extent during chunk allocation
  Btrfs: clear all space_info->full after removing a block group
  Btrfs: make flushoncommit mount option correctly wait on ordered_extents
  Btrfs: Avoid delayed reference update looping
  Btrfs: Fix ordering of key field checks in btrfs_previous_item
  Btrfs: find_free_dev_extent doesn't handle holes at the start of the device
  Btrfs: Remove code duplication in comp_keys
  Btrfs: async block group caching
  Btrfs: use hybrid extents+bitmap rb tree for free space
  Btrfs: Fix crash on read failures at mount
  Btrfs: remove of redundant btrfs_header_level
  Btrfs: adjust NULL test
  Btrfs: Remove broken sanity check from btrfs_rmap_block()
  Btrfs: convert nested spin_lock_irqsave to spin_lock
  Btrfs: make sure all dirty blocks are written at commit time
  Btrfs: fix locking issue in btrfs_find_next_key
  Btrfs: fix double increment of path->slots[0] in btrfs_next_leaf
  ...