err = -EINVAL;
if (old) {
- struct fuse_dev *fud = fuse_get_dev(old);
+ struct fuse_dev *fud = NULL;
+
+ /*
+ * Check against file->f_op because CUSE
+ * uses the same ioctl handler.
+ */
+ if (old->f_op == file->f_op &&
+ old->f_cred->user_ns == file->f_cred->user_ns)
+ fud = fuse_get_dev(old);
if (fud) {
mutex_lock(&fuse_mutex);