Merge tag 'ceph-for-4.17-rc1' of git://github.com/ceph/ceph-client

Pull ceph updates from Ilya Dryomov:
 "The big ticket items are:

   - support for rbd "fancy" striping (myself).

     The striping feature bit is now fully implemented, allowing mapping
     v2 images with non-default striping patterns. This completes
     support for --image-format 2.

   - CephFS quota support (Luis Henriques and Zheng Yan).

     This set is based on the new SnapRealm code in the upcoming v13.y.z
     ("Mimic") release. Quota handling will be rejected on older
     filesystems.

   - memory usage improvements in CephFS (Chengguang Xu).

     Directory specific bits have been split out of ceph_file_info and
     some effort went into improving cap reservation code to avoid OOM
     crashes.

  Also included a bunch of assorted fixes all over the place from
  Chengguang and others"

* tag 'ceph-for-4.17-rc1' of git://github.com/ceph/ceph-client: (67 commits)
  ceph: quota: report root dir quota usage in statfs
  ceph: quota: add counter for snaprealms with quota
  ceph: quota: cache inode pointer in ceph_snap_realm
  ceph: fix root quota realm check
  ceph: don't check quota for snap inode
  ceph: quota: update MDS when max_bytes is approaching
  ceph: quota: support for ceph.quota.max_bytes
  ceph: quota: don't allow cross-quota renames
  ceph: quota: support for ceph.quota.max_files
  ceph: quota: add initial infrastructure to support cephfs quotas
  rbd: remove VLA usage
  rbd: fix spelling mistake: "reregisteration" -> "reregistration"
  ceph: rename function drop_leases() to a more descriptive name
  ceph: fix invalid point dereference for error case in mdsc destroy
  ceph: return proper bool type to caller instead of pointer
  ceph: optimize memory usage
  ceph: optimize mds session register
  libceph, ceph: add __init attribution to init funcitons
  ceph: filter out used flags when printing unused open flags
  ceph: don't wait on writeback when there is no more dirty pages
  ...

Author: torvalds

Documentation/filesystems/ceph.txt

@@ -62,6 +62,18 @@ subdirectories, and a summation of all nested file sizes.  This makes
 the identification of large disk space consumers relatively quick, as
 no 'du' or similar recursive scan of the file system is required.
 
+Finally, Ceph also allows quotas to be set on any directory in the system.
+The quota can restrict the number of bytes or the number of files stored
+beneath that point in the directory hierarchy.  Quotas can be set using
+extended attributes 'ceph.quota.max_files' and 'ceph.quota.max_bytes', eg:
+
+ setfattr -n ceph.quota.max_bytes -v 100000000 /some/dir
+ getfattr -n ceph.quota.max_bytes /some/dir
+
+A limitation of the current quotas implementation is that it relies on the
+cooperation of the client mounting the file system to stop writers when a
+limit is reached.  A modified or adversarial client cannot be prevented
+from writing as much data as it needs.
 
 Mount Syntax
 ============
@@ -137,6 +149,10 @@ Mount Options
   noasyncreaddir
 	Do not use the dcache as above for readdir.
 
+  noquotadf
+        Report overall filesystem usage in statfs instead of using the root
+        directory quota.
+
 More Information
 ================