ceph: fix statfs for subdir mounts

When doing a mount using as base a directory that has 'max_bytes' quotas
statfs uses that value as the total; if a subdirectory is used instead,
the same 'max_bytes' too in statfs, unless there is another quota set.

Unfortunately, if this subdirectory only has the 'max_files' quota set,
then statfs uses the filesystem total.  Fix this by making sure we only
lookup realms that contain the 'max_bytes' quota.

Cc: Ryan Taylor <rptaylor@uvic.ca>
URL: https://tracker.ceph.com/issues/55090
Signed-off-by: Luís Henriques <lhenriques@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

1 files changed, 11 insertions, 8 deletions

diff --git a/fs/ceph/quota.c b/fs/ceph/quota.c
index a338a3ec0dc4..64592adfe48f 100644
--- a/fs/ceph/quota.c
+++ b/fs/ceph/quota.c
@@ -195,9 +195,9 @@ void ceph_cleanup_quotarealms_inodes(struct ceph_mds_client *mdsc)
 
 /*
  * This function walks through the snaprealm for an inode and returns the
- * ceph_snap_realm for the first snaprealm that has quotas set (either max_files
- * or max_bytes).  If the root is reached, return the root ceph_snap_realm
- * instead.
+ * ceph_snap_realm for the first snaprealm that has quotas set (max_files,
+ * max_bytes, or any, depending on the 'which_quota' argument).  If the root is
+ * reached, return the root ceph_snap_realm instead.
  *
  * Note that the caller is responsible for calling ceph_put_snap_realm() on the
  * returned realm.
@@ -209,7 +209,9 @@ void ceph_cleanup_quotarealms_inodes(struct ceph_mds_client *mdsc)
  * will be restarted.
  */
 static struct ceph_snap_realm *get_quota_realm(struct ceph_mds_client *mdsc,
-					       struct inode *inode, bool retry)
+					       struct inode *inode,
+					       enum quota_get_realm which_quota,
+					       bool retry)
 {
 	struct ceph_inode_info *ci = NULL;
 	struct ceph_snap_realm *realm, *next;
@@ -248,7 +250,7 @@ restart:
 		}
 
 		ci = ceph_inode(in);
-		has_quota = __ceph_has_any_quota(ci);
+		has_quota = __ceph_has_quota(ci, which_quota);
 		iput(in);
 
 		next = realm->parent;
@@ -279,8 +281,8 @@ restart:
 	 * dropped and we can then restart the whole operation.
 	 */
 	down_read(&mdsc->snap_rwsem);
-	old_realm = get_quota_realm(mdsc, old, true);
-	new_realm = get_quota_realm(mdsc, new, false);
+	old_realm = get_quota_realm(mdsc, old, QUOTA_GET_ANY, true);
+	new_realm = get_quota_realm(mdsc, new, QUOTA_GET_ANY, false);
 	if (PTR_ERR(new_realm) == -EAGAIN) {
 		up_read(&mdsc->snap_rwsem);
 		if (old_realm)
@@ -483,7 +485,8 @@ bool ceph_quota_update_statfs(struct ceph_fs_client *fsc, struct kstatfs *buf)
 	bool is_updated = false;
 
 	down_read(&mdsc->snap_rwsem);
-	realm = get_quota_realm(mdsc, d_inode(fsc->sb->s_root), true);
+	realm = get_quota_realm(mdsc, d_inode(fsc->sb->s_root),
+				QUOTA_GET_MAX_BYTES, true);
 	up_read(&mdsc->snap_rwsem);
 	if (!realm)
 		return false;