diff options
-rw-r--r-- | block/nbd.c | 50 |
1 files changed, 32 insertions, 18 deletions
diff --git a/block/nbd.c b/block/nbd.c index f2d5b47..15b569a 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -130,7 +130,8 @@ typedef struct BDRVNBDState { static void nbd_free_connect_thread(NBDConnectThread *thr); static int nbd_establish_connection(BlockDriverState *bs, SocketAddress *saddr, Error **errp); -static int nbd_co_establish_connection(BlockDriverState *bs, Error **errp); +static coroutine_fn QIOChannelSocket * +nbd_co_establish_connection(NBDConnectThread *thr, Error **errp); static void nbd_co_establish_connection_cancel(BlockDriverState *bs); static int nbd_client_handshake(BlockDriverState *bs, Error **errp); static void nbd_yank(void *opaque); @@ -416,22 +417,37 @@ static void *connect_thread_func(void *opaque) return NULL; } -static int coroutine_fn -nbd_co_establish_connection(BlockDriverState *bs, Error **errp) +/* + * Get a new connection in context of @thr: + * if the thread is running, wait for completion + * if the thread already succeeded in the background, and user didn't get the + * result, just return it now + * otherwise the thread is not running, so start a thread and wait for + * completion + */ +static coroutine_fn QIOChannelSocket * +nbd_co_establish_connection(NBDConnectThread *thr, Error **errp) { + QIOChannelSocket *sioc = NULL; QemuThread thread; - BDRVNBDState *s = bs->opaque; - NBDConnectThread *thr = s->connect_thread; - - assert(!s->sioc); qemu_mutex_lock(&thr->mutex); + /* + * Don't call nbd_co_establish_connection() in several coroutines in + * parallel. Only one call at once is supported. + */ + assert(!thr->wait_co); + if (!thr->running) { if (thr->sioc) { /* Previous attempt finally succeeded in background */ - goto out; + sioc = g_steal_pointer(&thr->sioc); + qemu_mutex_unlock(&thr->mutex); + + return sioc; } + thr->running = true; error_free(thr->err); thr->err = NULL; @@ -445,13 +461,12 @@ nbd_co_establish_connection(BlockDriverState *bs, Error **errp) /* * We are going to wait for connect-thread finish, but - * nbd_client_co_drain_begin() can interrupt. + * nbd_co_establish_connection_cancel() can interrupt. */ qemu_coroutine_yield(); qemu_mutex_lock(&thr->mutex); -out: if (thr->running) { /* * The connection attempt was canceled and the coroutine resumed @@ -463,17 +478,12 @@ out: } else { error_propagate(errp, thr->err); thr->err = NULL; - s->sioc = thr->sioc; - thr->sioc = NULL; - if (s->sioc) { - yank_register_function(BLOCKDEV_YANK_INSTANCE(bs->node_name), - nbd_yank, bs); - } + sioc = g_steal_pointer(&thr->sioc); } qemu_mutex_unlock(&thr->mutex); - return s->sioc ? 0 : -1; + return sioc; } /* @@ -541,11 +551,15 @@ static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s) s->ioc = NULL; } - if (nbd_co_establish_connection(s->bs, NULL) < 0) { + s->sioc = nbd_co_establish_connection(s->connect_thread, NULL); + if (!s->sioc) { ret = -ECONNREFUSED; goto out; } + yank_register_function(BLOCKDEV_YANK_INSTANCE(s->bs->node_name), nbd_yank, + s->bs); + bdrv_dec_in_flight(s->bs); ret = nbd_client_handshake(s->bs, NULL); |