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:
  Btrfs: fix panic when trying to destroy a newly allocated
  Btrfs: allow more metadata chunk preallocation
  Btrfs: fallback on uncompressed io if compressed io fails
  Btrfs: find ideal block group for caching
  Btrfs: avoid null deref in unpin_extent_cache()
  Btrfs: skip btrfs_release_path in btrfs_update_root and btrfs_del_root
  Btrfs: fix some metadata enospc issues
  Btrfs: fix how we set max_size for free space clusters
  Btrfs: cleanup transaction starting and fix journal_info usage
  Btrfs: fix data allocation hint start