vhost: configure all host notifiers in a single MR transaction
[qemu.git] / nbd / client-connection.c
blob0c5f917efac0b86e56e8dd5dfa4c9b4ee6bbb3b4
1 /*
2 * QEMU Block driver for NBD
4 * Copyright (c) 2021 Virtuozzo International GmbH.
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22 * THE SOFTWARE.
25 #include "qemu/osdep.h"
26 #include "trace.h"
28 #include "block/nbd.h"
30 #include "qapi/qapi-visit-sockets.h"
31 #include "qapi/clone-visitor.h"
33 struct NBDClientConnection {
34 /* Initialization constants, never change */
35 SocketAddress *saddr; /* address to connect to */
36 QCryptoTLSCreds *tlscreds;
37 char *tlshostname;
38 NBDExportInfo initial_info;
39 bool do_negotiation;
40 bool do_retry;
42 QemuMutex mutex;
44 NBDExportInfo updated_info;
46 * @sioc represents a successful result. While thread is running, @sioc is
47 * used only by thread and not protected by mutex. When thread is not
48 * running, @sioc is stolen by nbd_co_establish_connection() under mutex.
50 QIOChannelSocket *sioc;
51 QIOChannel *ioc;
53 * @err represents previous attempt. It may be copied by
54 * nbd_co_establish_connection() when it reports failure.
56 Error *err;
58 /* All further fields are accessed only under mutex */
59 bool running; /* thread is running now */
60 bool detached; /* thread is detached and should cleanup the state */
63 * wait_co: if non-NULL, which coroutine to wake in
64 * nbd_co_establish_connection() after yield()
66 Coroutine *wait_co;
70 * The function isn't protected by any mutex, only call it when the client
71 * connection attempt has not yet started.
73 void nbd_client_connection_enable_retry(NBDClientConnection *conn)
75 conn->do_retry = true;
78 NBDClientConnection *nbd_client_connection_new(const SocketAddress *saddr,
79 bool do_negotiation,
80 const char *export_name,
81 const char *x_dirty_bitmap,
82 QCryptoTLSCreds *tlscreds,
83 const char *tlshostname)
85 NBDClientConnection *conn = g_new(NBDClientConnection, 1);
87 object_ref(OBJECT(tlscreds));
88 *conn = (NBDClientConnection) {
89 .saddr = QAPI_CLONE(SocketAddress, saddr),
90 .tlscreds = tlscreds,
91 .tlshostname = g_strdup(tlshostname),
92 .do_negotiation = do_negotiation,
94 .initial_info.request_sizes = true,
95 .initial_info.structured_reply = true,
96 .initial_info.base_allocation = true,
97 .initial_info.x_dirty_bitmap = g_strdup(x_dirty_bitmap),
98 .initial_info.name = g_strdup(export_name ?: "")
101 qemu_mutex_init(&conn->mutex);
103 return conn;
106 static void nbd_client_connection_do_free(NBDClientConnection *conn)
108 if (conn->sioc) {
109 qio_channel_close(QIO_CHANNEL(conn->sioc), NULL);
110 object_unref(OBJECT(conn->sioc));
112 error_free(conn->err);
113 qapi_free_SocketAddress(conn->saddr);
114 g_free(conn->tlshostname);
115 object_unref(OBJECT(conn->tlscreds));
116 g_free(conn->initial_info.x_dirty_bitmap);
117 g_free(conn->initial_info.name);
118 g_free(conn);
122 * Connect to @addr and do NBD negotiation if @info is not null. If @tlscreds
123 * are given @outioc is returned. @outioc is provided only on success. The call
124 * may be cancelled from other thread by simply qio_channel_shutdown(sioc).
126 static int nbd_connect(QIOChannelSocket *sioc, SocketAddress *addr,
127 NBDExportInfo *info, QCryptoTLSCreds *tlscreds,
128 const char *tlshostname,
129 QIOChannel **outioc, Error **errp)
131 int ret;
133 if (outioc) {
134 *outioc = NULL;
137 ret = qio_channel_socket_connect_sync(sioc, addr, errp);
138 if (ret < 0) {
139 return ret;
142 qio_channel_set_delay(QIO_CHANNEL(sioc), false);
144 if (!info) {
145 return 0;
148 ret = nbd_receive_negotiate(NULL, QIO_CHANNEL(sioc), tlscreds,
149 tlshostname,
150 outioc, info, errp);
151 if (ret < 0) {
153 * nbd_receive_negotiate() may setup tls ioc and return it even on
154 * failure path. In this case we should use it instead of original
155 * channel.
157 if (outioc && *outioc) {
158 qio_channel_close(QIO_CHANNEL(*outioc), NULL);
159 object_unref(OBJECT(*outioc));
160 *outioc = NULL;
161 } else {
162 qio_channel_close(QIO_CHANNEL(sioc), NULL);
165 return ret;
168 return 0;
171 static void *connect_thread_func(void *opaque)
173 NBDClientConnection *conn = opaque;
174 int ret;
175 bool do_free;
176 uint64_t timeout = 1;
177 uint64_t max_timeout = 16;
179 qemu_mutex_lock(&conn->mutex);
180 while (!conn->detached) {
181 Error *local_err = NULL;
183 assert(!conn->sioc);
184 conn->sioc = qio_channel_socket_new();
186 qemu_mutex_unlock(&conn->mutex);
188 conn->updated_info = conn->initial_info;
190 ret = nbd_connect(conn->sioc, conn->saddr,
191 conn->do_negotiation ? &conn->updated_info : NULL,
192 conn->tlscreds, conn->tlshostname,
193 &conn->ioc, &local_err);
196 * conn->updated_info will finally be returned to the user. Clear the
197 * pointers to our internally allocated strings, which are IN parameters
198 * of nbd_receive_negotiate() and therefore nbd_connect(). Caller
199 * shoudn't be interested in these fields.
201 conn->updated_info.x_dirty_bitmap = NULL;
202 conn->updated_info.name = NULL;
204 qemu_mutex_lock(&conn->mutex);
206 error_free(conn->err);
207 conn->err = NULL;
208 error_propagate(&conn->err, local_err);
210 if (ret < 0) {
211 object_unref(OBJECT(conn->sioc));
212 conn->sioc = NULL;
213 if (conn->do_retry && !conn->detached) {
214 trace_nbd_connect_thread_sleep(timeout);
215 qemu_mutex_unlock(&conn->mutex);
217 sleep(timeout);
218 if (timeout < max_timeout) {
219 timeout *= 2;
222 qemu_mutex_lock(&conn->mutex);
223 continue;
227 break;
230 /* mutex is locked */
232 assert(conn->running);
233 conn->running = false;
234 if (conn->wait_co) {
235 aio_co_wake(conn->wait_co);
236 conn->wait_co = NULL;
238 do_free = conn->detached;
240 qemu_mutex_unlock(&conn->mutex);
242 if (do_free) {
243 nbd_client_connection_do_free(conn);
246 return NULL;
249 void nbd_client_connection_release(NBDClientConnection *conn)
251 bool do_free = false;
253 if (!conn) {
254 return;
257 WITH_QEMU_LOCK_GUARD(&conn->mutex) {
258 assert(!conn->detached);
259 if (conn->running) {
260 conn->detached = true;
261 } else {
262 do_free = true;
264 if (conn->sioc) {
265 qio_channel_shutdown(QIO_CHANNEL(conn->sioc),
266 QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
270 if (do_free) {
271 nbd_client_connection_do_free(conn);
276 * Get a new connection in context of @conn:
277 * if the thread is running, wait for completion
278 * if the thread already succeeded in the background, and user didn't get the
279 * result, just return it now
280 * otherwise the thread is not running, so start a thread and wait for
281 * completion
283 * If @blocking is false, don't wait for the thread, return immediately.
285 * If @info is not NULL, also do nbd-negotiation after successful connection.
286 * In this case info is used only as out parameter, and is fully initialized by
287 * nbd_co_establish_connection(). "IN" fields of info as well as related only to
288 * nbd_receive_export_list() would be zero (see description of NBDExportInfo in
289 * include/block/nbd.h).
291 QIOChannel *coroutine_fn
292 nbd_co_establish_connection(NBDClientConnection *conn, NBDExportInfo *info,
293 bool blocking, Error **errp)
295 QemuThread thread;
297 if (conn->do_negotiation) {
298 assert(info);
301 WITH_QEMU_LOCK_GUARD(&conn->mutex) {
303 * Don't call nbd_co_establish_connection() in several coroutines in
304 * parallel. Only one call at once is supported.
306 assert(!conn->wait_co);
308 if (!conn->running) {
309 if (conn->sioc) {
310 /* Previous attempt finally succeeded in background */
311 if (conn->do_negotiation) {
312 memcpy(info, &conn->updated_info, sizeof(*info));
313 if (conn->ioc) {
314 /* TLS channel now has own reference to parent */
315 object_unref(OBJECT(conn->sioc));
316 conn->sioc = NULL;
318 return g_steal_pointer(&conn->ioc);
322 assert(!conn->ioc);
324 return QIO_CHANNEL(g_steal_pointer(&conn->sioc));
327 conn->running = true;
328 qemu_thread_create(&thread, "nbd-connect",
329 connect_thread_func, conn, QEMU_THREAD_DETACHED);
332 if (!blocking) {
333 if (conn->err) {
334 error_propagate(errp, error_copy(conn->err));
335 } else {
336 error_setg(errp, "No connection at the moment");
339 return NULL;
342 conn->wait_co = qemu_coroutine_self();
346 * We are going to wait for connect-thread finish, but
347 * nbd_co_establish_connection_cancel() can interrupt.
349 qemu_coroutine_yield();
351 WITH_QEMU_LOCK_GUARD(&conn->mutex) {
352 if (conn->running) {
354 * The connection attempt was canceled and the coroutine resumed
355 * before the connection thread finished its job. Report the
356 * attempt as failed, but leave the connection thread running,
357 * to reuse it for the next connection attempt.
359 if (conn->err) {
360 error_propagate(errp, error_copy(conn->err));
361 } else {
363 * The only possible case here is cancelling by open_timer
364 * during nbd_open(). So, the error message is for that case.
365 * If we have more use cases, we can refactor
366 * nbd_co_establish_connection_cancel() to take an additional
367 * parameter cancel_reason, that would be passed than to the
368 * caller of cancelled nbd_co_establish_connection().
370 error_setg(errp, "Connection attempt cancelled by timeout");
373 return NULL;
374 } else {
375 /* Thread finished. There must be either error or sioc */
376 assert(!conn->err != !conn->sioc);
378 if (conn->err) {
379 error_propagate(errp, error_copy(conn->err));
380 return NULL;
383 if (conn->do_negotiation) {
384 memcpy(info, &conn->updated_info, sizeof(*info));
385 if (conn->ioc) {
386 /* TLS channel now has own reference to parent */
387 object_unref(OBJECT(conn->sioc));
388 conn->sioc = NULL;
390 return g_steal_pointer(&conn->ioc);
394 assert(!conn->ioc);
396 return QIO_CHANNEL(g_steal_pointer(&conn->sioc));
400 abort(); /* unreachable */
404 * nbd_co_establish_connection_cancel
405 * Cancel nbd_co_establish_connection() asynchronously.
407 * Note that this function neither directly stops the thread nor closes the
408 * socket, but rather safely wakes nbd_co_establish_connection() which is
409 * sleeping in yield()
411 void nbd_co_establish_connection_cancel(NBDClientConnection *conn)
413 Coroutine *wait_co;
415 WITH_QEMU_LOCK_GUARD(&conn->mutex) {
416 wait_co = g_steal_pointer(&conn->wait_co);
419 if (wait_co) {
420 aio_co_wake(wait_co);