On Wed, Mar 4, 2020 at 5:48 AM Mike Christie <mchristi@xxxxxxxxxx> wrote: > > On 03/03/2020 03:12 PM, Josef Bacik wrote: > > On 2/28/20 1:40 AM, Hou Pu wrote: > >> Nbd server with multiple connections could be upgraded since > >> 560bc4b (nbd: handle dead connections). But if only one conncection > >> is configured, after we take down nbd server, all inflight IO > >> would finally timeout and return error. We could requeue them > >> like what we do with multiple connections and wait for new socket > >> in submit path. > >> > >> Signed-off-by: Hou Pu <houpu@xxxxxxxxxxxxx> > >> --- > >> drivers/block/nbd.c | 17 +++++++++-------- > >> 1 file changed, 9 insertions(+), 8 deletions(-) > >> > >> diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c > >> index 78181908f0df..83070714888b 100644 > >> --- a/drivers/block/nbd.c > >> +++ b/drivers/block/nbd.c > >> @@ -395,16 +395,19 @@ static enum blk_eh_timer_return > >> nbd_xmit_timeout(struct request *req, > >> } > >> config = nbd->config; > >> - if (config->num_connections > 1) { > >> + if (config->num_connections > 1 || > >> + (config->num_connections == 1 && nbd->tag_set.timeout)) { > > > > This is every connection, do you mean to couple this with > > dead_conn_timeout? Thanks, > > Except this case tag_set.timeout==0 and num_connections == 1. As Mike said below. Regards. Hou. > > In > > commit 2da22da573481cc4837e246d0eee4d518b3f715e > Author: Mike Christie <mchristi@xxxxxxxxxx> > Date: Tue Aug 13 11:39:52 2019 -0500 > > nbd: fix zero cmd timeout handling v2 > > we can set tag_set.timeout=0 again. > > So if timeout != 0 and num_connections = 1, we requeue here and let > nbd_handle_cmd->wait_for_reconnect decide to wait or fail the command if > dead_conn_timeout is not set. > > If timeout = 0, then we give it more time because it might have just > been a slow server or connection. I think this behavior is wrong for the > case Hou is fixing. See comment in the next patch. > Yes. While we are waiting for a slow connection, we also take care if the socket is reconfigured. Regards. Hou.