io_uring: break links on shutdown failure

Ensure that the return value of __sys_shutdown_sock() is used to
potentially break links to the request, if we fail.

Fixes: 36f4fa6886 ("io_uring: add support for shutdown(2)")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -3784,6 +3784,8 @@ static int io_shutdown(struct io_kiocb *req, bool force_nonblock)
 		return -ENOTSOCK;
 
 	ret = __sys_shutdown_sock(sock, req->shutdown.how);
+	if (ret < 0)
+		req_set_fail_links(req);
 	io_req_complete(req, ret);
 	return 0;
 #else