Pull f2fs updates from Jaegeuk Kim:
 "In this round, we introduce sysfile-based quota support which is
  required for Android by default. In addition, we allow that users are
  able to reserve some blocks in runtime to mitigate performance drops
  in low free space.

  Enhancements:
   - assign proper data segments according to write_hints given by user
   - issue cache_flush on dirty devices only among multiple devices
   - exploit cp_error flag and add more faults to enhance fault
     injection test
   - conduct more readaheads during f2fs_readdir
   - add a range for discard commands

  Bug fixes:
   - fix zero stat->st_blocks when inline_data is set
   - drop crypto key and free stale memory pointer while evict_inode is
     failing
   - fix some corner cases in free space and segment management
   - fix wrong last_disk_size

  This series includes lots of clean-ups and code enhancement in terms
  of xattr operations, discard/flush command control. In addition, it
  adds versatile debugfs entries to monitor f2fs status"

* tag 'f2fs-for-4.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (75 commits)
  f2fs: deny accessing encryption policy if encryption is off
  f2fs: inject fault in inc_valid_node_count
  f2fs: fix to clear FI_NO_PREALLOC
  f2fs: expose quota information in debugfs
  f2fs: separate nat entry mem alloc from nat_tree_lock
  f2fs: validate before set/clear free nat bitmap
  f2fs: avoid opened loop codes in __add_ino_entry
  f2fs: apply write hints to select the type of segments for buffered write
  f2fs: introduce scan_curseg_cache for cleanup
  f2fs: optimize the way of traversing free_nid_bitmap
  f2fs: keep scanning until enough free nids are acquired
  f2fs: trace checkpoint reason in fsync()
  f2fs: keep isize once block is reserved cross EOF
  f2fs: avoid race in between GC and block exchange
  f2fs: save a multiplication for last_nid calculation
  f2fs: fix summary info corruption
  f2fs: remove dead code in update_meta_page
  f2fs: remove unneeded semicolon
  f2fs: don't bother with inode->i_version
  f2fs: check curseg space before foreground GC
  ...