Pull f2fs updates from Jaegeuk Kim:
 "This patch-set includes the following major enhancement patches.
   - introduce large directory support
   - introduce f2fs_issue_flush to merge redundant flush commands
   - merge write IOs as much as possible aligned to the segment
   - add sysfs entries to tune the f2fs configuration
   - use radix_tree for the free_nid_list to reduce in-memory operations
   - remove costly bit operations in f2fs_find_entry
   - enhance the readahead flow for CP/NAT/SIT/SSA blocks

  The other bug fixes are as follows:
   - recover xattr node blocks correctly after sudden-power-cut
   - fix to calculate the maximum number of node ids
   - enhance to handle many error cases

  And, there are a bunch of cleanups"

* tag 'for-f2fs-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (62 commits)
  f2fs: fix wrong statistics of inline data
  f2fs: check the acl's validity before setting
  f2fs: introduce f2fs_issue_flush to avoid redundant flush issue
  f2fs: fix to cover io->bio with io_rwsem
  f2fs: fix error path when fail to read inline data
  f2fs: use list_for_each_entry{_safe} for simplyfying code
  f2fs: avoid free slab cache under spinlock
  f2fs: avoid unneeded lookup when xattr name length is too long
  f2fs: avoid unnecessary bio submit when wait page writeback
  f2fs: return -EIO when node id is not matched
  f2fs: avoid RECLAIM_FS-ON-W warning
  f2fs: skip unnecessary node writes during fsync
  f2fs: introduce fi->i_sem to protect fi's info
  f2fs: change reclaim rate in percentage
  f2fs: add missing documentation for dir_level
  f2fs: remove unnecessary threshold
  f2fs: throttle the memory footprint with a sysfs entry
  f2fs: avoid to drop nat entries due to the negative nr_shrink
  f2fs: call f2fs_wait_on_page_writeback instead of native function
  f2fs: introduce nr_pages_to_write for segment alignment
  ...