Pull f2fs updates from Jaegeuk Kim:
 "The major work includes fixing and enhancing the existing extent_cache
  feature, which has been well settling down so far and now it becomes a
  default mount option accordingly.

  Also, this version newly registers a f2fs memory shrinker to reclaim
  several objects consumed by a couple of data structures in order to
  avoid memory pressures.

  Another new feature is to add ioctl(F2FS_GARBAGE_COLLECT) which
  triggers a cleaning job explicitly by users.

  Most of the other patches are to fix bugs occurred in the corner cases
  across the whole code area"

* tag 'for-f2fs-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (85 commits)
  f2fs: upset segment_info repair
  f2fs: avoid accessing NULL pointer in f2fs_drop_largest_extent
  f2fs: update extent tree in batches
  f2fs: fix to release inode correctly
  f2fs: handle f2fs_truncate error correctly
  f2fs: avoid unneeded initializing when converting inline dentry
  f2fs: atomically set inode->i_flags
  f2fs: fix wrong pointer access during try_to_free_nids
  f2fs: use __GFP_NOFAIL to avoid infinite loop
  f2fs: lookup neighbor extent nodes for merging later
  f2fs: split __insert_extent_tree_ret for readability
  f2fs: kill dead code in __insert_extent_tree
  f2fs: adjust showing of extent cache stat
  f2fs: add largest/cached stat in extent cache
  f2fs: fix incorrect mapping for bmap
  f2fs: add annotation for space utilization of regular/inline dentry
  f2fs: fix to update cached_en of extent tree properly
  f2fs: fix typo
  f2fs: check the node block address of newly allocated nid
  f2fs: go out for insert_inode_locked failure
  ...