[PATCH 08/19] nvme-tcp: start error recovery when a send fails

[Keith Busch]

From: Josef Bacik <josef at toxicpanda.com>

When the target closes a connection, nvme_tcp_state_change() calls
nvme_tcp_error_recovery(), which does nothing unless the controller is
live. While connecting that's fine for the queue being set up, its
Connect fails and the attempt with it. But if an already connected queue
is closed at the end of the attempt, nothing fails, the notification is
lost and the controller goes live on a dead socket. Every request on
that queue then fails with "failed to send request -32" and is retried,
forever with native multipathing, and if it's the admin queue the first
keep-alive fails too. Nothing but a manual reset recovers it. The Linux
target closes its connections at exactly that moment after a fatal
error.

Start error recovery when a request can't be sent, as nvme-rdma does.

Fixes: 3f2304f8c6d6 ("nvme-tcp: add NVMe over TCP host driver")
Cc: Keith Busch <kbusch at kernel.org>
Cc: Christoph Hellwig <hch at lst.de>
Cc: Sagi Grimberg <sagi at grimberg.me>
Reviewed-by: Hannes Reinecke <hare at kernel.org>
Signed-off-by: Josef Bacik <josef at toxicpanda.com>
Signed-off-by: Jens Axboe <axboe at kernel.dk>
Signed-off-by: Keith Busch <kbusch at kernel.org>
---
 drivers/nvme/host/tcp.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index bc46e5f3eaa79..9e15311e7d9cc 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -1437,6 +1437,8 @@ static int nvme_tcp_try_send(struct nvme_tcp_queue *queue)
 			"failed to send request %d\n", ret);
 		nvme_tcp_fail_request(queue->request);
 		nvme_tcp_done_send_req(queue);
+		/* The close may have come when nobody could act on it */
+		nvme_tcp_error_recovery(&queue->ctrl->ctrl);
 	}
 out:
 	memalloc_noreclaim_restore(noreclaim_flag);
-- 
2.52.0