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 v2: - Replaced inodes list in mdsc by an rbtree. This is because we need to able to keep track errors in lookupino so that we don't keep sending the same useless request for inodes that have failed. This also resulted in reworking the locking in lookup_quotarealm_inode, so that 2 threads can lookup the same inode at the same time - No need to set realm->inode in lookup_quotarealm_inode() as the lookupino has set it already. Changes since v1: - Loop to free mdsc->quotarealms_inodes_list list was moved further down where it's not possible to race with insertions. This way there's no need to hold the spinlock anymore. - Clarified comments regarding the get_quota_realm function 'retry' parameter, both in the function itself and in function ceph_quota_is_same_realm, where that param is set to 'false' - Distinguish between 'realm->inode is NULL' and igrab failures, both in get_quota_realm and check_quota_exceeded 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 | 19 ++++++ fs/ceph/mds_client.h | 18 +++++ fs/ceph/quota.c | 158 ++++++++++++++++++++++++++++++++++++++++--- fs/ceph/super.h | 1 + 5 files changed, 199 insertions(+), 11 deletions(-)
