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dkim=none (message not signed) header.d=none;openvz.org; dmarc=none action=none header.from=virtuozzo.com; Received: from AM7PR08MB5494.eurprd08.prod.outlook.com (2603:10a6:20b:dc::15) by AM6PR08MB3861.eurprd08.prod.outlook.com (2603:10a6:20b:80::30) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4065.21; Wed, 28 Apr 2021 08:14:47 +0000 Received: from AM7PR08MB5494.eurprd08.prod.outlook.com ([fe80::b403:c1a9:6bb7:133]) by AM7PR08MB5494.eurprd08.prod.outlook.com ([fe80::b403:c1a9:6bb7:133%7]) with mapi id 15.20.4065.027; Wed, 28 Apr 2021 08:14:47 +0000 Subject: Re: [PATCH v3 14/33] nbd: move connection code from block/nbd to nbd/client-connection To: Roman Kagan , qemu-block@nongnu.org, qemu-devel@nongnu.org, eblake@redhat.com, mreitz@redhat.com, kwolf@redhat.com, den@openvz.org References: <20210416080911.83197-1-vsementsov@virtuozzo.com> <20210416080911.83197-15-vsementsov@virtuozzo.com> From: Vladimir Sementsov-Ogievskiy Message-ID: <84aaa2dc-7a86-c540-fd82-6729d568cd50@virtuozzo.com> Date: Wed, 28 Apr 2021 11:14:44 +0300 User-Agent: Mozilla/5.0 (X11; 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envelope-from=vsementsov@virtuozzo.com; helo=EUR05-DB8-obe.outbound.protection.outlook.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, MSGID_FROM_MTA_HEADER=0.001, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" 28.04.2021 01:45, Roman Kagan wrote: > On Fri, Apr 16, 2021 at 11:08:52AM +0300, Vladimir Sementsov-Ogievskiy wrote: >> We now have bs-independent connection API, which consists of four >> functions: >> >> nbd_client_connection_new() >> nbd_client_connection_unref() >> nbd_co_establish_connection() >> nbd_co_establish_connection_cancel() >> >> Move them to a separate file together with NBDClientConnection >> structure which becomes private to the new API. >> >> Signed-off-by: Vladimir Sementsov-Ogievskiy >> --- >> include/block/nbd.h | 11 +++ >> block/nbd.c | 187 ----------------------------------- >> nbd/client-connection.c | 212 ++++++++++++++++++++++++++++++++++++++++ >> nbd/meson.build | 1 + >> 4 files changed, 224 insertions(+), 187 deletions(-) >> create mode 100644 nbd/client-connection.c >> >> diff --git a/include/block/nbd.h b/include/block/nbd.h >> index 5f34d23bb0..57381be76f 100644 >> --- a/include/block/nbd.h >> +++ b/include/block/nbd.h >> @@ -406,4 +406,15 @@ const char *nbd_info_lookup(uint16_t info); >> const char *nbd_cmd_lookup(uint16_t info); >> const char *nbd_err_lookup(int err); >> >> +/* nbd/client-connection.c */ >> +typedef struct NBDClientConnection NBDClientConnection; >> + >> +NBDClientConnection *nbd_client_connection_new(const SocketAddress *saddr); >> +void nbd_client_connection_release(NBDClientConnection *conn); >> + >> +QIOChannelSocket *coroutine_fn >> +nbd_co_establish_connection(NBDClientConnection *conn, Error **errp); >> + >> +void coroutine_fn nbd_co_establish_connection_cancel(NBDClientConnection *conn); >> + >> #endif >> diff --git a/block/nbd.c b/block/nbd.c >> index 8531d019b2..9bd68dcf10 100644 >> --- a/block/nbd.c >> +++ b/block/nbd.c >> @@ -66,24 +66,6 @@ typedef enum NBDClientState { >> NBD_CLIENT_QUIT >> } NBDClientState; >> >> -typedef struct NBDClientConnection { >> - /* Initialization constants */ >> - SocketAddress *saddr; /* address to connect to */ >> - >> - /* >> - * Result of last attempt. Valid in FAIL and SUCCESS states. >> - * If you want to steal error, don't forget to set pointer to NULL. >> - */ >> - QIOChannelSocket *sioc; >> - Error *err; >> - >> - QemuMutex mutex; >> - /* All further fields are protected by mutex */ >> - bool running; /* thread is running now */ >> - bool detached; /* thread is detached and should cleanup the state */ >> - Coroutine *wait_co; /* nbd_co_establish_connection() wait in yield() */ >> -} NBDClientConnection; >> - >> typedef struct BDRVNBDState { >> QIOChannelSocket *sioc; /* The master data channel */ >> QIOChannel *ioc; /* The current I/O channel which may differ (eg TLS) */ >> @@ -118,12 +100,8 @@ typedef struct BDRVNBDState { >> NBDClientConnection *conn; >> } BDRVNBDState; >> >> -static void nbd_client_connection_release(NBDClientConnection *conn); >> static int nbd_establish_connection(BlockDriverState *bs, SocketAddress *saddr, >> Error **errp); >> -static coroutine_fn QIOChannelSocket * >> -nbd_co_establish_connection(NBDClientConnection *conn, Error **errp); >> -static void nbd_co_establish_connection_cancel(NBDClientConnection *conn); >> static int nbd_client_handshake(BlockDriverState *bs, Error **errp); >> static void nbd_yank(void *opaque); >> >> @@ -340,171 +318,6 @@ static bool nbd_client_connecting_wait(BDRVNBDState *s) >> return qatomic_load_acquire(&s->state) == NBD_CLIENT_CONNECTING_WAIT; >> } >> >> -static NBDClientConnection * >> -nbd_client_connection_new(const SocketAddress *saddr) >> -{ >> - NBDClientConnection *conn = g_new(NBDClientConnection, 1); >> - >> - *conn = (NBDClientConnection) { >> - .saddr = QAPI_CLONE(SocketAddress, saddr), >> - }; >> - >> - qemu_mutex_init(&conn->mutex); >> - >> - return conn; >> -} >> - >> -static void nbd_client_connection_do_free(NBDClientConnection *conn) >> -{ >> - if (conn->sioc) { >> - qio_channel_close(QIO_CHANNEL(conn->sioc), NULL); >> - object_unref(OBJECT(conn->sioc)); >> - } >> - error_free(conn->err); >> - qapi_free_SocketAddress(conn->saddr); >> - g_free(conn); >> -} >> - >> -static void *connect_thread_func(void *opaque) >> -{ >> - NBDClientConnection *conn = opaque; >> - bool do_free; >> - int ret; >> - >> - conn->sioc = qio_channel_socket_new(); >> - >> - error_free(conn->err); >> - conn->err = NULL; >> - ret = qio_channel_socket_connect_sync(conn->sioc, conn->saddr, &conn->err); >> - if (ret < 0) { >> - object_unref(OBJECT(conn->sioc)); >> - conn->sioc = NULL; >> - } >> - >> - qemu_mutex_lock(&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; >> - >> - qemu_mutex_unlock(&conn->mutex); >> - >> - if (do_free) { >> - nbd_client_connection_do_free(conn); >> - } >> - >> - return NULL; >> -} >> - >> -static void nbd_client_connection_release(NBDClientConnection *conn) >> -{ >> - bool do_free; >> - >> - if (!conn) { >> - return; >> - } >> - >> - qemu_mutex_lock(&conn->mutex); >> - if (conn->running) { >> - conn->detached = true; >> - } >> - do_free = !conn->running && !conn->detached; >> - qemu_mutex_unlock(&conn->mutex); >> - >> - if (do_free) { >> - nbd_client_connection_do_free(conn); >> - } >> -} >> - >> -/* >> - * Get a new connection in context of @conn: >> - * if thread is running, wait for completion >> - * if thread is already succeeded in background, and user didn't get the >> - * result, just return it now >> - * otherwise if thread is not running, start a thread and wait for completion >> - */ >> -static coroutine_fn QIOChannelSocket * >> -nbd_co_establish_connection(NBDClientConnection *conn, Error **errp) >> -{ >> - QIOChannelSocket *sioc = NULL; >> - QemuThread thread; >> - >> - qemu_mutex_lock(&conn->mutex); >> - >> - /* >> - * Don't call nbd_co_establish_connection() in several coroutines in >> - * parallel. Only one call at once is supported. >> - */ >> - assert(!conn->wait_co); >> - >> - if (!conn->running) { >> - if (conn->sioc) { >> - /* Previous attempt finally succeeded in background */ >> - sioc = g_steal_pointer(&conn->sioc); >> - qemu_mutex_unlock(&conn->mutex); >> - >> - return sioc; >> - } >> - >> - conn->running = true; >> - error_free(conn->err); >> - conn->err = NULL; >> - qemu_thread_create(&thread, "nbd-connect", >> - connect_thread_func, conn, QEMU_THREAD_DETACHED); >> - } >> - >> - conn->wait_co = qemu_coroutine_self(); >> - >> - qemu_mutex_unlock(&conn->mutex); >> - >> - /* >> - * We are going to wait for connect-thread finish, but >> - * nbd_co_establish_connection_cancel() can interrupt. >> - */ >> - qemu_coroutine_yield(); >> - >> - qemu_mutex_lock(&conn->mutex); >> - >> - if (conn->running) { >> - /* >> - * Obviously, drained section wants to start. Report the attempt as >> - * failed. Still connect thread is executing in background, and its >> - * result may be used for next connection attempt. >> - */ >> - error_setg(errp, "Connection attempt cancelled by other operation"); >> - } else { >> - error_propagate(errp, conn->err); >> - conn->err = NULL; >> - sioc = g_steal_pointer(&conn->sioc); >> - } >> - >> - qemu_mutex_unlock(&conn->mutex); >> - >> - return sioc; >> -} >> - >> -/* >> - * nbd_co_establish_connection_cancel >> - * Cancel nbd_co_establish_connection() asynchronously. Note, that it doesn't >> - * stop the thread itself neither close the socket. It just safely wakes >> - * nbd_co_establish_connection() sleeping in the yield(). >> - */ >> -static void nbd_co_establish_connection_cancel(NBDClientConnection *conn) >> -{ >> - qemu_mutex_lock(&conn->mutex); >> - >> - if (conn->wait_co) { >> - aio_co_schedule(NULL, conn->wait_co); >> - conn->wait_co = NULL; >> - } >> - >> - qemu_mutex_unlock(&conn->mutex); >> -} >> - >> static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s) >> { >> int ret; >> diff --git a/nbd/client-connection.c b/nbd/client-connection.c >> new file mode 100644 >> index 0000000000..4e39a5b1af >> --- /dev/null >> +++ b/nbd/client-connection.c >> @@ -0,0 +1,212 @@ >> +/* >> + * QEMU Block driver for NBD >> + * >> + * Copyright (c) 2021 Virtuozzo International GmbH. >> + * >> + * Permission is hereby granted, free of charge, to any person obtaining a copy >> + * of this software and associated documentation files (the "Software"), to deal >> + * in the Software without restriction, including without limitation the rights >> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell >> + * copies of the Software, and to permit persons to whom the Software is >> + * furnished to do so, subject to the following conditions: >> + * >> + * The above copyright notice and this permission notice shall be included in >> + * all copies or substantial portions of the Software. >> + * >> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR >> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, >> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL >> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER >> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, >> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN >> + * THE SOFTWARE. >> + */ >> + >> +#include "qemu/osdep.h" >> + >> +#include "block/nbd.h" >> + >> +#include "qapi/qapi-visit-sockets.h" >> +#include "qapi/clone-visitor.h" >> + >> +struct NBDClientConnection { >> + /* Initialization constants */ >> + SocketAddress *saddr; /* address to connect to */ >> + >> + /* >> + * Result of last attempt. Valid in FAIL and SUCCESS states. >> + * If you want to steal error, don't forget to set pointer to NULL. >> + */ >> + QIOChannelSocket *sioc; >> + Error *err; > > These two are also manipulated under the mutex. Consider also updating > the comment: both these pointers are to be "stolen" by the caller, with > the former being valid when the connection succeeds and the latter > otherwise. > Hmm. I should move mutex and "All further" comment above these two fields. Ok, I'll think on updating the comment (probably as an additional patch, to keep this as a simple movement). I don't like to document that they are stolen by caller(). For me it sounds like caller is user of the interface. And caller of nbd_co_establish_connection() doesn't stole anything: the structure is private now.. > >> + >> + QemuMutex mutex; >> + /* All further fields are protected by mutex */ >> + bool running; /* thread is running now */ >> + bool detached; /* thread is detached and should cleanup the state */ >> + Coroutine *wait_co; /* nbd_co_establish_connection() wait in yield() */ >> +}; >> + >> +NBDClientConnection *nbd_client_connection_new(const SocketAddress *saddr) >> +{ >> + NBDClientConnection *conn = g_new(NBDClientConnection, 1); >> + >> + *conn = (NBDClientConnection) { >> + .saddr = QAPI_CLONE(SocketAddress, saddr), >> + }; >> + >> + qemu_mutex_init(&conn->mutex); >> + >> + return conn; >> +} >> + >> +static void nbd_client_connection_do_free(NBDClientConnection *conn) >> +{ >> + if (conn->sioc) { >> + qio_channel_close(QIO_CHANNEL(conn->sioc), NULL); >> + object_unref(OBJECT(conn->sioc)); >> + } >> + error_free(conn->err); >> + qapi_free_SocketAddress(conn->saddr); >> + g_free(conn); >> +} >> + >> +static void *connect_thread_func(void *opaque) >> +{ >> + NBDClientConnection *conn = opaque; >> + bool do_free; >> + int ret; >> + >> + conn->sioc = qio_channel_socket_new(); >> + >> + error_free(conn->err); >> + conn->err = NULL; >> + ret = qio_channel_socket_connect_sync(conn->sioc, conn->saddr, &conn->err); >> + if (ret < 0) { >> + object_unref(OBJECT(conn->sioc)); >> + conn->sioc = NULL; >> + } >> + >> + qemu_mutex_lock(&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; >> + >> + qemu_mutex_unlock(&conn->mutex); >> + >> + if (do_free) { >> + nbd_client_connection_do_free(conn); >> + } >> + >> + return NULL; >> +} >> + >> +void nbd_client_connection_release(NBDClientConnection *conn) >> +{ >> + bool do_free; >> + >> + if (!conn) { >> + return; >> + } >> + >> + qemu_mutex_lock(&conn->mutex); >> + if (conn->running) { >> + conn->detached = true; >> + } >> + do_free = !conn->running && !conn->detached; >> + qemu_mutex_unlock(&conn->mutex); >> + >> + if (do_free) { >> + nbd_client_connection_do_free(conn); >> + } >> +} >> + >> +/* >> + * Get a new connection in context of @conn: >> + * if thread is running, wait for completion >> + * if thread is already succeeded in background, and user didn't get the >> + * result, just return it now >> + * otherwise if thread is not running, start a thread and wait for completion >> + */ >> +QIOChannelSocket *coroutine_fn >> +nbd_co_establish_connection(NBDClientConnection *conn, Error **errp) >> +{ >> + QIOChannelSocket *sioc = NULL; >> + QemuThread thread; >> + >> + qemu_mutex_lock(&conn->mutex); >> + >> + /* >> + * Don't call nbd_co_establish_connection() in several coroutines in >> + * parallel. Only one call at once is supported. >> + */ >> + assert(!conn->wait_co); >> + >> + if (!conn->running) { >> + if (conn->sioc) { >> + /* Previous attempt finally succeeded in background */ >> + sioc = g_steal_pointer(&conn->sioc); >> + qemu_mutex_unlock(&conn->mutex); >> + >> + return sioc; >> + } >> + >> + conn->running = true; >> + error_free(conn->err); >> + conn->err = NULL; >> + qemu_thread_create(&thread, "nbd-connect", >> + connect_thread_func, conn, QEMU_THREAD_DETACHED); >> + } >> + >> + conn->wait_co = qemu_coroutine_self(); >> + >> + qemu_mutex_unlock(&conn->mutex); >> + >> + /* >> + * We are going to wait for connect-thread finish, but >> + * nbd_co_establish_connection_cancel() can interrupt. >> + */ >> + qemu_coroutine_yield(); >> + >> + qemu_mutex_lock(&conn->mutex); >> + >> + if (conn->running) { >> + /* >> + * Obviously, drained section wants to start. Report the attempt as >> + * failed. Still connect thread is executing in background, and its >> + * result may be used for next connection attempt. >> + */ >> + error_setg(errp, "Connection attempt cancelled by other operation"); >> + } else { >> + error_propagate(errp, conn->err); >> + conn->err = NULL; >> + sioc = g_steal_pointer(&conn->sioc); >> + } >> + >> + qemu_mutex_unlock(&conn->mutex); >> + >> + return sioc; >> +} >> + >> +/* >> + * nbd_co_establish_connection_cancel >> + * Cancel nbd_co_establish_connection() asynchronously. Note, that it doesn't >> + * stop the thread itself neither close the socket. It just safely wakes >> + * nbd_co_establish_connection() sleeping in the yield(). >> + */ >> +void coroutine_fn nbd_co_establish_connection_cancel(NBDClientConnection *conn) >> +{ >> + qemu_mutex_lock(&conn->mutex); >> + >> + if (conn->wait_co) { >> + aio_co_schedule(NULL, conn->wait_co); >> + conn->wait_co = NULL; >> + } >> + >> + qemu_mutex_unlock(&conn->mutex); >> +} >> diff --git a/nbd/meson.build b/nbd/meson.build >> index 2baaa36948..b26d70565e 100644 >> --- a/nbd/meson.build >> +++ b/nbd/meson.build >> @@ -1,5 +1,6 @@ >> block_ss.add(files( >> 'client.c', >> + 'client-connection.c', >> 'common.c', >> )) >> blockdev_ss.add(files( >> -- >> 2.29.2 >> -- Best regards, Vladimir