From: Josef Bacik <jbacik@fb.com>
Date: Thu, 8 Jun 2017 15:39:30 -0400
Subject: [PATCH] nbd: set sk->sk_sndtimeo for our sockets
Git-commit: dc88e34d69d87c370deaa9d613dac8e3a0411f59
Patch-mainline: v4.13-rc1
References: bsc#1104967,FATE#325924

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>
Acked-by: Hannes Reinecke <hare@suse.com>
---
 drivers/block/nbd.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index c5e52f66d3d4..6de9f9943a0e 100644
--- 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);
-- 
2.16.4