Hi, As recently reported in the ceph-users mailing-list[1], the kernel client behaves differently from the fuse client regarding mounting subdirs where quotas are in effect. I've also created a bug to track this issue[2]. The following patches are a possible way of fixing this issue. The performance impact should be close to zero if the mount is done in the CephFS root inode. When we're mounting subdirs, we may have extra queries to the MDSs, depending on how many extra realms we'll need to loop through. Changes since RFC: The 1st patch hasn't been changed since the initial RFC. The 2nd patch has been refactored to include the following changes: - Zheng Yan's suggestions, i.e, move inode references from the realms to ceph_mds_client instance - It now also handles other cases where an MDS lookup may need to be performed: * statfs when there are quotas * renames, to forbid cross-quota renames [1] http://lists.ceph.com/pipermail/ceph-users-ceph.com/2019-February/033357.html [2] https://tracker.ceph.com/issues/38482 Cheers, -- Luís Luis Henriques (2): ceph: factor out ceph_lookup_inode() ceph: quota: fix quota subdir mounts fs/ceph/export.c | 14 ++++++- fs/ceph/mds_client.c | 14 +++++++ fs/ceph/mds_client.h | 2 + fs/ceph/quota.c | 91 +++++++++++++++++++++++++++++++++++++++----- fs/ceph/super.h | 3 ++ 5 files changed, 113 insertions(+), 11 deletions(-)
