Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs

Pull btrfs update frm Chris Mason:
 "This is our usual merge window set of bug fixes, performance
  improvements and cleanups.  Miao Xie has some really nice
  optimizations for writeback.

  Josef also expanded our sanity checks quite a bit; these make up a big
  chunk of the new lines"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (98 commits)
  Btrfs: rename btrfs_start_all_delalloc_inodes
  Btrfs: don't wait for the completion of all the ordered extents
  Btrfs: don't wait for all the async delalloc when shrinking delalloc
  Btrfs: fix the confusion between delalloc bytes and metadata bytes
  Btrfs: pick up the code for the item number calculation in flush_space()
  Btrfs: wait for the ordered extent only when we want
  Btrfs: remove unnecessary initialization and memory barrior in shrink_delalloc()
  Btrfs: avoid unnecessary scrub workers allocation
  Btrfs: check file extent type before anything else
  btrfs: Remove useless variable in write_ctree_super()
  btrfs: Fix checkpatch.pl warning of spacing issues
  btrfs: Replace kmalloc with kmalloc_array
  btrfs: Enclose macros with complex values within parenthesis
  btrfs: Use WARN_ON()'s return value in place of WARN_ON(1)
  btrfs: Remove redundant local zero structure
  btrfs: Pack struct btrfs_device
  btrfs: Replace multiple atomic_inc() with atomic_add()
  btrfs: Add helper function for free_root_pointers()
  Btrfs: fix a crash when running balance and defrag concurrently
  Btrfs: do not run snapshot-aware defragment on error
  ...

include/uapi/linux/magic.h

@@ -71,6 +71,6 @@
 #define USBDEVICE_SUPER_MAGIC	0x9fa2
 #define MTD_INODE_FS_MAGIC      0x11307854
 #define ANON_INODE_FS_MAGIC	0x09041934
-
+#define BTRFS_TEST_MAGIC	0x73727279
 
 #endif /* __LINUX_MAGIC_H__ */