diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 47cfd8935b9c..bb372859c0ad 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -351,7 +351,9 @@ struct ceph_inode_info {
 	struct rb_root i_caps;           /* cap list */
 	struct ceph_cap *i_auth_cap;     /* authoritative cap, if any */
 	unsigned i_dirty_caps, i_flushing_caps;     /* mask of dirtied fields */
-	struct list_head i_dirty_item, i_flushing_item;
+	struct list_head i_dirty_item, i_flushing_item; /* protected by
+							 * mdsc->cap_dirty_lock
+							 */
 	/* we need to track cap writeback on a per-cap-bit basis, to allow
 	 * overlapping, pipelined cap flushes to the mds.  we can probably
 	 * reduce the tid to 8 bits if we're concerned about inode size. */