Pull ceph updates from Ilya Dryomov:
 "The highlights include:

   - a large series of fixes and improvements to the snapshot-handling
     code (Zheng Yan)

   - individual read/write OSD requests passed down to libceph are now
     limited to 16M in size to avoid hitting OSD-side limits (Zheng Yan)

   - encode MStatfs v2 message to allow for more accurate space usage
     reporting (Douglas Fuller)

   - switch to the new writeback error tracking infrastructure (Jeff
     Layton)"

* tag 'ceph-for-4.14-rc1' of git://github.com/ceph/ceph-client: (35 commits)
  ceph: stop on-going cached readdir if mds revokes FILE_SHARED cap
  ceph: wait on writeback after writing snapshot data
  ceph: fix capsnap dirty pages accounting
  ceph: ignore wbc->range_{start,end} when write back snapshot data
  ceph: fix "range cyclic" mode writepages
  ceph: cleanup local variables in ceph_writepages_start()
  ceph: optimize pagevec iterating in ceph_writepages_start()
  ceph: make writepage_nounlock() invalidate page that beyonds EOF
  ceph: properly get capsnap's size in get_oldest_context()
  ceph: remove stale check in ceph_invalidatepage()
  ceph: queue cap snap only when snap realm's context changes
  ceph: handle race between vmtruncate and queuing cap snap
  ceph: fix message order check in handle_cap_export()
  ceph: fix NULL pointer dereference in ceph_flush_snaps()
  ceph: adjust 36 checks for NULL pointers
  ceph: delete an unnecessary return statement in update_dentry_lease()
  ceph: ENOMEM pr_err in __get_or_create_frag() is redundant
  ceph: check negative offsets in ceph_llseek()
  ceph: more accurate statfs
  ceph: properly set snap follows for cap reconnect
  ...