On Fri, Apr 16, 2021 at 11:08:56AM +0300, Vladimir Sementsov-Ogievskiy wrote:
> Now, when thread can do negotiation and retry, it may run relatively
> long. We need a mechanism to stop it, when user is not interested in
> result anymore. So, on nbd_client_connection_release() let's shutdown
> the socked, and do not retry connection if thread is detached.
This kinda answers my question to the previous patch about reconnect
cancellation.
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
> ---
> nbd/client-connection.c | 36 ++++++++++++++++++++++++++----------
> 1 file changed, 26 insertions(+), 10 deletions(-)
>
> diff --git a/nbd/client-connection.c b/nbd/client-connection.c
> index 002bd91f42..54f73c6c24 100644
> --- a/nbd/client-connection.c
> +++ b/nbd/client-connection.c
> @@ -158,9 +158,13 @@ static void *connect_thread_func(void *opaque)
> uint64_t timeout = 1;
> uint64_t max_timeout = 16;
>
> - while (true) {
> + qemu_mutex_lock(&conn->mutex);
> + while (!conn->detached) {
> + assert(!conn->sioc);
> conn->sioc = qio_channel_socket_new();
>
> + qemu_mutex_unlock(&conn->mutex);
> +
> error_free(conn->err);
> conn->err = NULL;
> conn->updated_info = conn->initial_info;
> @@ -171,14 +175,20 @@ static void *connect_thread_func(void *opaque)
> conn->updated_info.x_dirty_bitmap = NULL;
> conn->updated_info.name = NULL;
>
> + qemu_mutex_lock(&conn->mutex);
> +
> if (ret < 0) {
> object_unref(OBJECT(conn->sioc));
> conn->sioc = NULL;
> - if (conn->do_retry) {
> + if (conn->do_retry && !conn->detached) {
> + qemu_mutex_unlock(&conn->mutex);
> +
> sleep(timeout);
> if (timeout < max_timeout) {
> timeout *= 2;
> }
> +
> + qemu_mutex_lock(&conn->mutex);
> continue;
> }
> }
> @@ -186,15 +196,17 @@ static void *connect_thread_func(void *opaque)
> break;
> }
>
> - WITH_QEMU_LOCK_GUARD(&conn->mutex) {
> - assert(conn->running);
> - conn->running = false;
> - if (conn->wait_co) {
> - aio_co_schedule(NULL, conn->wait_co);
> - conn->wait_co = NULL;
> - }
> - do_free = conn->detached;
> + /* mutex is locked */
> +
> + assert(conn->running);
> + conn->running = false;
> + if (conn->wait_co) {
> + aio_co_schedule(NULL, conn->wait_co);
> + conn->wait_co = NULL;
> }
> + do_free = conn->detached;
> +
> + qemu_mutex_unlock(&conn->mutex);
This basically reverts some hunks from patch 15 "nbd/client-connection:
use QEMU_LOCK_GUARD". How about dropping them there (they weren't an
obvious improvement even then).
Roman.
>
> if (do_free) {
> nbd_client_connection_do_free(conn);
> @@ -215,6 +227,10 @@ void nbd_client_connection_release(NBDClientConnection
> *conn)
> if (conn->running) {
> conn->detached = true;
> }
> + if (conn->sioc) {
> + qio_channel_shutdown(QIO_CHANNEL(conn->sioc),
> + QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
> + }
> do_free = !conn->running && !conn->detached;
> qemu_mutex_unlock(&conn->mutex);
>
> --
> 2.29.2
>
