If we configured io timeout of nbd0 to 100s. Later after we finished using it, we configured nbd0 again and set the io timeout to 0. We expect it would timeout after 30 seconds and keep retry. But in fact we could not change the timeout when we set it to 0. the timeout is still the original 100s. So change the timeout to default 30s when we set it to zero. It also behaves same as commit 2da22da57348 ("nbd: fix zero cmd timeout handling v2"). It becomes more important if we were reconfigure a nbd device and the io timeout it set to zero. Because it could take 30s to detect the new socket and thus io could be completed more quickly compared to 100s. Signed-off-by: Hou Pu <houpu@xxxxxxxxxxxxx> --- drivers/block/nbd.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index ce7e9f223b20..bc9dc1f847e1 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -1360,6 +1360,8 @@ static void nbd_set_cmd_timeout(struct nbd_device *nbd, u64 timeout) nbd->tag_set.timeout = timeout * HZ; if (timeout) blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ); + else + blk_queue_rq_timeout(nbd->disk->queue, 30 * HZ); } /* Must be called with config_lock held */ -- 2.11.0