Ceph » CephFS

We found client won't get quota updated for a long time under following case. We found this issue on Luminous, but it might be also existed on previous versions.

Steps to reproduce:
1. mount a ceph-fuse client-1 (for admin) on host-1 and set quota as follows.

[ceph@x1 ~]$ sudo setfattr -n ceph.quota.max_bytes -v 100000 /mnt/cephfs/test10/      
[ceph@x1 ~]$ sudo setfattr -n ceph.quota.max_bytes -v 200000 /mnt/cephfs/test10/test11/

2. unmount above ceph-fuse client-1
3. mount another ceph-fuse client-2 (for user) on host-2 and copy some files into sub-directory test11. Since test10's quota is less than test11's, quota will be exceeded first on test10.

[ceph@x2 ~]$ sudo cp config /mnt/cephfs/test10/test11/2
cp: error writing '/mnt/cephfs/test10/test11/2': Disk quota exceeded
cp: failed to extend '/mnt/cephfs/test10/test11/2': Disk quota exceeded

4. mount a ceph-fuse client-1 (for admin) on host-1 again and change test10's quota.

[ceph@x1 ~]$ sudo setfattr -n ceph.quota.max_bytes -v 200000 /mnt/cephfs/test10/

5. unmount above ceph-fuse client-1

6. continue copying files into sub-directory test11 on host-2. It will still return quota exceeded for a long time, or until explicitly call getfattr to get quota back.

[ceph@x2 ~]$ sudo cp config /mnt/cephfs/test10/test11/3
cp: error writing '/mnt/cephfs/test10/test11/3': Disk quota exceeded
cp: failed to extend '/mnt/cephfs/test10/test11/3': Disk quota exceeded

The reason is that MDS only broadcasts quota under two cases, but above case is not one of them. So I think we could broadcast quota to relevant clients proactively if quota is explicitly set by someone.