+ /*
+ * We must always pass in a valid mount pointer. Historically
+ * callers got away with not passing it, but we must enforce this at
+ * the earliest possible point now to avoid strange problems deep in the
+ * filesystem stack.
+ */
+ if (!mnt) {
+ printk(KERN_WARNING "%s called with NULL vfsmount\n", __func__);
+ dump_stack();
+ return ERR_PTR(-EINVAL);
+ }
+