Merge tag 'for-f2fs-3.20' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs

Pull f2fs updates from Jaegeuk Kim:
 "Major changes are to:
   - add f2fs_io_tracer and F2FS_IOC_GETVERSION
   - fix wrong acl assignment from parent
   - fix accessing wrong data blocks
   - fix wrong condition check for f2fs_sync_fs
   - align start block address for direct_io
   - add and refactor the readahead flows of FS metadata
   - refactor atomic and volatile write policies

  But most of patches are for clean-ups and minor bug fixes.  Some of
  them refactor old code too"

* tag 'for-f2fs-3.20' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (64 commits)
  f2fs: use spinlock for segmap_lock instead of rwlock
  f2fs: fix accessing wrong indexed data blocks
  f2fs: avoid variable length array
  f2fs: fix sparse warnings
  f2fs: allocate data blocks in advance for f2fs_direct_IO
  f2fs: introduce macros to convert bytes and blocks in f2fs
  f2fs: call set_buffer_new for get_block
  f2fs: check nod...