} else if (cmd->updateref &&
                        (write_in_full(lock->lock_fd,
                                sha1_to_hex(cb.last_kept_sha1), 40) != 40 ||
-                        write_in_full(lock->lock_fd, "\n", 1) != 1 ||
+                        write_str_in_full(lock->lock_fd, "\n") != 1 ||
                         close_ref(lock) < 0)) {
                        status |= error("Couldn't write %s",
                                lock->lk->filename);