nbd: set sk->sk_sndtimeo for our sockets

If the nbd server stops receiving packets altogether we will get stuck
waiting for them to receive indefinitely as the tcp buffer will never
empty, which looks like a deadlock.  Fix this by setting the sk send
timeout to our configured timeout, that way if the server really
misbehaves we'll disconnect cleanly instead of waiting forever.

Reported-by: Dan Melnic <dmm@fb.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index c5e52f66d3d44b2fdf4e3726d51870a7c7c49441..6de9f9943a0e74377be2a0c5552cbfafe3a06ff4 100644 (file)
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -914,6 +914,7 @@ static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg)
                        continue;
                }
                sk_set_memalloc(sock->sk);
+               sock->sk->sk_sndtimeo = nbd->tag_set.timeout;
                atomic_inc(&config->recv_threads);
                refcount_inc(&nbd->config_refs);
                old = nsock->sock;
@@ -1083,6 +1084,7 @@ static int nbd_start_device(struct nbd_device *nbd)
                        return -ENOMEM;
                }
                sk_set_memalloc(config->socks[i]->sock->sk);
+               config->socks[i]->sock->sk->sk_sndtimeo = nbd->tag_set.timeout;
                atomic_inc(&config->recv_threads);
                refcount_inc(&nbd->config_refs);
                INIT_WORK(&args->work, recv_work);