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, 24 insertions, 4 deletions

diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index d749c96070f6..dd7dac0f984a 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -1279,9 +1279,29 @@ extern void ceph_fs_debugfs_init(struct ceph_fs_client *client);
 extern void ceph_fs_debugfs_cleanup(struct ceph_fs_client *client);
 
 /* quota.c */
-static inline bool __ceph_has_any_quota(struct ceph_inode_info *ci)
+
+enum quota_get_realm {
+	QUOTA_GET_MAX_FILES,
+	QUOTA_GET_MAX_BYTES,
+	QUOTA_GET_ANY
+};
+
+static inline bool __ceph_has_quota(struct ceph_inode_info *ci,
+				    enum quota_get_realm which)
 {
-	return ci->i_max_files || ci->i_max_bytes;
+	bool has_quota = false;
+
+	switch (which) {
+	case QUOTA_GET_MAX_BYTES:
+		has_quota = !!ci->i_max_bytes;
+		break;
+	case QUOTA_GET_MAX_FILES:
+		has_quota = !!ci->i_max_files;
+		break;
+	default:
+		has_quota = !!(ci->i_max_files || ci->i_max_bytes);
+	}
+	return has_quota;
 }
 
 extern void ceph_adjust_quota_realms_count(struct inode *inode, bool inc);
@@ -1290,10 +1310,10 @@ static inline void __ceph_update_quota(struct ceph_inode_info *ci,
 				       u64 max_bytes, u64 max_files)
 {
 	bool had_quota, has_quota;
-	had_quota = __ceph_has_any_quota(ci);
+	had_quota = __ceph_has_quota(ci, QUOTA_GET_ANY);
 	ci->i_max_bytes = max_bytes;
 	ci->i_max_files = max_files;
-	has_quota = __ceph_has_any_quota(ci);
+	has_quota = __ceph_has_quota(ci, QUOTA_GET_ANY);
 
 	if (had_quota != has_quota)
 		ceph_adjust_quota_realms_count(&ci->vfs_inode, has_quota);