| Message ID | 1527698711-14919-1-git-send-email-kvigor@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, May 30, 2018 at 10:45:11AM -0600, kvigor@gmail.com wrote: > From: Kevin Vigor <kvigor@fb.com> > > When a userspace client requests a NBD device be disconnected, the > DISCONNECT_REQUESTED flag is set. While this flag is set, the driver > will not inform userspace when a connection is closed. > > Unfortunately the flag was never cleared, so once a disconnect was > requested the driver would thereafter never tell userspace about a > closed connection. Thus when connections failed due to timeout, no > attempt to reconnect was made and eventually the device would fail. > > Fix by clearing the DISCONNECT_REQUESTED flag (and setting the > DISCONNECTED flag) once all connections are closed. > > Changes relative to v1 (https://marc.info/?l=linux-block&m=152763540418902): > > * remove pointless wake_up() -> wake_up_all() change. > Usually you want to put the changelog after the --- bit below so we can all see it but it doesn't end up in the git changelog. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Thanks, Josef
On 5/30/18 10:45 AM, kvigor@gmail.com wrote: > From: Kevin Vigor <kvigor@fb.com> > > When a userspace client requests a NBD device be disconnected, the > DISCONNECT_REQUESTED flag is set. While this flag is set, the driver > will not inform userspace when a connection is closed. > > Unfortunately the flag was never cleared, so once a disconnect was > requested the driver would thereafter never tell userspace about a > closed connection. Thus when connections failed due to timeout, no > attempt to reconnect was made and eventually the device would fail. > > Fix by clearing the DISCONNECT_REQUESTED flag (and setting the > DISCONNECTED flag) once all connections are closed. Applied, thanks Kevin.
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index afbc202..1cd041b 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -213,7 +213,15 @@ static void nbd_mark_nsock_dead(struct nbd_device *nbd, struct nbd_sock *nsock, } if (!nsock->dead) { kernel_sock_shutdown(nsock->sock, SHUT_RDWR); - atomic_dec(&nbd->config->live_connections); + if (atomic_dec_return(&nbd->config->live_connections) == 0) { + if (test_and_clear_bit(NBD_DISCONNECT_REQUESTED, + &nbd->config->runtime_flags)) { + set_bit(NBD_DISCONNECTED, + &nbd->config->runtime_flags); + dev_info(nbd_to_dev(nbd), + "Disconnected due to user request.\n"); + } + } } nsock->dead = true; nsock->pending = NULL; @@ -292,7 +300,9 @@ static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req, if (config->num_connections > 1) { dev_err_ratelimited(nbd_to_dev(nbd), - "Connection timed out, retrying\n"); + "Connection timed out, retrying (%d/%d alive)\n", + atomic_read(&config->live_connections), + config->num_connections); /* * Hooray we have more connections, requeue this IO, the submit * path will put it on a real connection. @@ -714,10 +724,9 @@ static int wait_for_reconnect(struct nbd_device *nbd) return 0; if (test_bit(NBD_DISCONNECTED, &config->runtime_flags)) return 0; - wait_event_timeout(config->conn_wait, - atomic_read(&config->live_connections), - config->dead_conn_timeout); - return atomic_read(&config->live_connections); + return wait_event_timeout(config->conn_wait, + atomic_read(&config->live_connections) > 0, + config->dead_conn_timeout) > 0; } static int nbd_handle_cmd(struct nbd_cmd *cmd, int index)