diff --git a/fs/mount.h b/fs/mount.h
index eb62ad2..4a5f1dc 100644
--- a/fs/mount.h
+++ b/fs/mount.h
@@ -25,6 +25,7 @@
 	struct list_head mnt_slave_list;/* list of slave mounts */
 	struct list_head mnt_slave;	/* slave list entry */
 	struct mount *mnt_master;	/* slave is on master->mnt_slave_list */
+	struct mnt_namespace *mnt_ns;	/* containing namespace */
 };
 
 static inline struct mount *real_mount(struct vfsmount *mnt)