vmxnet3: Use common MAC address tracing macros
[qemu.git] / block / nbd-client.c
1 /*
2 * QEMU Block driver for NBD
3 *
4 * Copyright (C) 2008 Bull S.A.S.
5 * Author: Laurent Vivier <Laurent.Vivier@bull.net>
6 *
7 * Some parts:
8 * Copyright (C) 2007 Anthony Liguori <anthony@codemonkey.ws>
9 *
10 * Permission is hereby granted, free of charge, to any person obtaining a copy
11 * of this software and associated documentation files (the "Software"), to deal
12 * in the Software without restriction, including without limitation the rights
13 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
14 * copies of the Software, and to permit persons to whom the Software is
15 * furnished to do so, subject to the following conditions:
16 *
17 * The above copyright notice and this permission notice shall be included in
18 * all copies or substantial portions of the Software.
19 *
20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
23 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
24 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
25 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
26 * THE SOFTWARE.
27 */
28
29 #include "qemu/osdep.h"
30 #include "nbd-client.h"
31
32 #define HANDLE_TO_INDEX(bs, handle) ((handle) ^ ((uint64_t)(intptr_t)bs))
33 #define INDEX_TO_HANDLE(bs, index) ((index) ^ ((uint64_t)(intptr_t)bs))
34
35 static void nbd_recv_coroutines_enter_all(NbdClientSession *s)
36 {
37 int i;
38
39 for (i = 0; i < MAX_NBD_REQUESTS; i++) {
40 if (s->recv_coroutine[i]) {
41 qemu_coroutine_enter(s->recv_coroutine[i], NULL);
42 }
43 }
44 }
45
46 static void nbd_teardown_connection(BlockDriverState *bs)
47 {
48 NbdClientSession *client = nbd_get_client_session(bs);
49
50 if (!client->ioc) { /* Already closed */
51 return;
52 }
53
54 /* finish any pending coroutines */
55 qio_channel_shutdown(client->ioc,
56 QIO_CHANNEL_SHUTDOWN_BOTH,
57 NULL);
58 nbd_recv_coroutines_enter_all(client);
59
60 nbd_client_detach_aio_context(bs);
61 object_unref(OBJECT(client->sioc));
62 client->sioc = NULL;
63 object_unref(OBJECT(client->ioc));
64 client->ioc = NULL;
65 }
66
67 static void nbd_reply_ready(void *opaque)
68 {
69 BlockDriverState *bs = opaque;
70 NbdClientSession *s = nbd_get_client_session(bs);
71 uint64_t i;
72 int ret;
73
74 if (!s->ioc) { /* Already closed */
75 return;
76 }
77
78 if (s->reply.handle == 0) {
79 /* No reply already in flight. Fetch a header. It is possible
80 * that another thread has done the same thing in parallel, so
81 * the socket is not readable anymore.
82 */
83 ret = nbd_receive_reply(s->ioc, &s->reply);
84 if (ret == -EAGAIN) {
85 return;
86 }
87 if (ret < 0) {
88 s->reply.handle = 0;
89 goto fail;
90 }
91 }
92
93 /* There's no need for a mutex on the receive side, because the
94 * handler acts as a synchronization point and ensures that only
95 * one coroutine is called until the reply finishes. */
96 i = HANDLE_TO_INDEX(s, s->reply.handle);
97 if (i >= MAX_NBD_REQUESTS) {
98 goto fail;
99 }
100
101 if (s->recv_coroutine[i]) {
102 qemu_coroutine_enter(s->recv_coroutine[i], NULL);
103 return;
104 }
105
106 fail:
107 nbd_teardown_connection(bs);
108 }
109
110 static void nbd_restart_write(void *opaque)
111 {
112 BlockDriverState *bs = opaque;
113
114 qemu_coroutine_enter(nbd_get_client_session(bs)->send_coroutine, NULL);
115 }
116
117 static int nbd_co_send_request(BlockDriverState *bs,
118 struct nbd_request *request,
119 QEMUIOVector *qiov, int offset)
120 {
121 NbdClientSession *s = nbd_get_client_session(bs);
122 AioContext *aio_context;
123 int rc, ret, i;
124
125 qemu_co_mutex_lock(&s->send_mutex);
126
127 for (i = 0; i < MAX_NBD_REQUESTS; i++) {
128 if (s->recv_coroutine[i] == NULL) {
129 s->recv_coroutine[i] = qemu_coroutine_self();
130 break;
131 }
132 }
133
134 g_assert(qemu_in_coroutine());
135 assert(i < MAX_NBD_REQUESTS);
136 request->handle = INDEX_TO_HANDLE(s, i);
137
138 if (!s->ioc) {
139 qemu_co_mutex_unlock(&s->send_mutex);
140 return -EPIPE;
141 }
142
143 s->send_coroutine = qemu_coroutine_self();
144 aio_context = bdrv_get_aio_context(bs);
145
146 aio_set_fd_handler(aio_context, s->sioc->fd, false,
147 nbd_reply_ready, nbd_restart_write, bs);
148 if (qiov) {
149 qio_channel_set_cork(s->ioc, true);
150 rc = nbd_send_request(s->ioc, request);
151 if (rc >= 0) {
152 ret = nbd_wr_syncv(s->ioc, qiov->iov, qiov->niov,
153 offset, request->len, 0);
154 if (ret != request->len) {
155 rc = -EIO;
156 }
157 }
158 qio_channel_set_cork(s->ioc, false);
159 } else {
160 rc = nbd_send_request(s->ioc, request);
161 }
162 aio_set_fd_handler(aio_context, s->sioc->fd, false,
163 nbd_reply_ready, NULL, bs);
164 s->send_coroutine = NULL;
165 qemu_co_mutex_unlock(&s->send_mutex);
166 return rc;
167 }
168
169 static void nbd_co_receive_reply(NbdClientSession *s,
170 struct nbd_request *request, struct nbd_reply *reply,
171 QEMUIOVector *qiov, int offset)
172 {
173 int ret;
174
175 /* Wait until we're woken up by the read handler. TODO: perhaps
176 * peek at the next reply and avoid yielding if it's ours? */
177 qemu_coroutine_yield();
178 *reply = s->reply;
179 if (reply->handle != request->handle ||
180 !s->ioc) {
181 reply->error = EIO;
182 } else {
183 if (qiov && reply->error == 0) {
184 ret = nbd_wr_syncv(s->ioc, qiov->iov, qiov->niov,
185 offset, request->len, 1);
186 if (ret != request->len) {
187 reply->error = EIO;
188 }
189 }
190
191 /* Tell the read handler to read another header. */
192 s->reply.handle = 0;
193 }
194 }
195
196 static void nbd_coroutine_start(NbdClientSession *s,
197 struct nbd_request *request)
198 {
199 /* Poor man semaphore. The free_sema is locked when no other request
200 * can be accepted, and unlocked after receiving one reply. */
201 if (s->in_flight >= MAX_NBD_REQUESTS - 1) {
202 qemu_co_mutex_lock(&s->free_sema);
203 assert(s->in_flight < MAX_NBD_REQUESTS);
204 }
205 s->in_flight++;
206
207 /* s->recv_coroutine[i] is set as soon as we get the send_lock. */
208 }
209
210 static void nbd_coroutine_end(NbdClientSession *s,
211 struct nbd_request *request)
212 {
213 int i = HANDLE_TO_INDEX(s, request->handle);
214 s->recv_coroutine[i] = NULL;
215 if (s->in_flight-- == MAX_NBD_REQUESTS) {
216 qemu_co_mutex_unlock(&s->free_sema);
217 }
218 }
219
220 static int nbd_co_readv_1(BlockDriverState *bs, int64_t sector_num,
221 int nb_sectors, QEMUIOVector *qiov,
222 int offset)
223 {
224 NbdClientSession *client = nbd_get_client_session(bs);
225 struct nbd_request request = { .type = NBD_CMD_READ };
226 struct nbd_reply reply;
227 ssize_t ret;
228
229 request.from = sector_num * 512;
230 request.len = nb_sectors * 512;
231
232 nbd_coroutine_start(client, &request);
233 ret = nbd_co_send_request(bs, &request, NULL, 0);
234 if (ret < 0) {
235 reply.error = -ret;
236 } else {
237 nbd_co_receive_reply(client, &request, &reply, qiov, offset);
238 }
239 nbd_coroutine_end(client, &request);
240 return -reply.error;
241
242 }
243
244 static int nbd_co_writev_1(BlockDriverState *bs, int64_t sector_num,
245 int nb_sectors, QEMUIOVector *qiov,
246 int offset, int flags)
247 {
248 NbdClientSession *client = nbd_get_client_session(bs);
249 struct nbd_request request = { .type = NBD_CMD_WRITE };
250 struct nbd_reply reply;
251 ssize_t ret;
252
253 if (flags & BDRV_REQ_FUA) {
254 assert(client->nbdflags & NBD_FLAG_SEND_FUA);
255 request.type |= NBD_CMD_FLAG_FUA;
256 }
257
258 request.from = sector_num * 512;
259 request.len = nb_sectors * 512;
260
261 nbd_coroutine_start(client, &request);
262 ret = nbd_co_send_request(bs, &request, qiov, offset);
263 if (ret < 0) {
264 reply.error = -ret;
265 } else {
266 nbd_co_receive_reply(client, &request, &reply, NULL, 0);
267 }
268 nbd_coroutine_end(client, &request);
269 return -reply.error;
270 }
271
272 /* qemu-nbd has a limit of slightly less than 1M per request. Try to
273 * remain aligned to 4K. */
274 #define NBD_MAX_SECTORS 2040
275
276 int nbd_client_co_readv(BlockDriverState *bs, int64_t sector_num,
277 int nb_sectors, QEMUIOVector *qiov)
278 {
279 int offset = 0;
280 int ret;
281 while (nb_sectors > NBD_MAX_SECTORS) {
282 ret = nbd_co_readv_1(bs, sector_num, NBD_MAX_SECTORS, qiov, offset);
283 if (ret < 0) {
284 return ret;
285 }
286 offset += NBD_MAX_SECTORS * 512;
287 sector_num += NBD_MAX_SECTORS;
288 nb_sectors -= NBD_MAX_SECTORS;
289 }
290 return nbd_co_readv_1(bs, sector_num, nb_sectors, qiov, offset);
291 }
292
293 int nbd_client_co_writev(BlockDriverState *bs, int64_t sector_num,
294 int nb_sectors, QEMUIOVector *qiov, int flags)
295 {
296 int offset = 0;
297 int ret;
298 while (nb_sectors > NBD_MAX_SECTORS) {
299 ret = nbd_co_writev_1(bs, sector_num, NBD_MAX_SECTORS, qiov, offset,
300 flags);
301 if (ret < 0) {
302 return ret;
303 }
304 offset += NBD_MAX_SECTORS * 512;
305 sector_num += NBD_MAX_SECTORS;
306 nb_sectors -= NBD_MAX_SECTORS;
307 }
308 return nbd_co_writev_1(bs, sector_num, nb_sectors, qiov, offset, flags);
309 }
310
311 int nbd_client_co_flush(BlockDriverState *bs)
312 {
313 NbdClientSession *client = nbd_get_client_session(bs);
314 struct nbd_request request = { .type = NBD_CMD_FLUSH };
315 struct nbd_reply reply;
316 ssize_t ret;
317
318 if (!(client->nbdflags & NBD_FLAG_SEND_FLUSH)) {
319 return 0;
320 }
321
322 request.from = 0;
323 request.len = 0;
324
325 nbd_coroutine_start(client, &request);
326 ret = nbd_co_send_request(bs, &request, NULL, 0);
327 if (ret < 0) {
328 reply.error = -ret;
329 } else {
330 nbd_co_receive_reply(client, &request, &reply, NULL, 0);
331 }
332 nbd_coroutine_end(client, &request);
333 return -reply.error;
334 }
335
336 int nbd_client_co_discard(BlockDriverState *bs, int64_t sector_num,
337 int nb_sectors)
338 {
339 NbdClientSession *client = nbd_get_client_session(bs);
340 struct nbd_request request = { .type = NBD_CMD_TRIM };
341 struct nbd_reply reply;
342 ssize_t ret;
343
344 if (!(client->nbdflags & NBD_FLAG_SEND_TRIM)) {
345 return 0;
346 }
347 request.from = sector_num * 512;
348 request.len = nb_sectors * 512;
349
350 nbd_coroutine_start(client, &request);
351 ret = nbd_co_send_request(bs, &request, NULL, 0);
352 if (ret < 0) {
353 reply.error = -ret;
354 } else {
355 nbd_co_receive_reply(client, &request, &reply, NULL, 0);
356 }
357 nbd_coroutine_end(client, &request);
358 return -reply.error;
359
360 }
361
362 void nbd_client_detach_aio_context(BlockDriverState *bs)
363 {
364 aio_set_fd_handler(bdrv_get_aio_context(bs),
365 nbd_get_client_session(bs)->sioc->fd,
366 false, NULL, NULL, NULL);
367 }
368
369 void nbd_client_attach_aio_context(BlockDriverState *bs,
370 AioContext *new_context)
371 {
372 aio_set_fd_handler(new_context, nbd_get_client_session(bs)->sioc->fd,
373 false, nbd_reply_ready, NULL, bs);
374 }
375
376 void nbd_client_close(BlockDriverState *bs)
377 {
378 NbdClientSession *client = nbd_get_client_session(bs);
379 struct nbd_request request = {
380 .type = NBD_CMD_DISC,
381 .from = 0,
382 .len = 0
383 };
384
385 if (client->ioc == NULL) {
386 return;
387 }
388
389 nbd_send_request(client->ioc, &request);
390
391 nbd_teardown_connection(bs);
392 }
393
394 int nbd_client_init(BlockDriverState *bs,
395 QIOChannelSocket *sioc,
396 const char *export,
397 QCryptoTLSCreds *tlscreds,
398 const char *hostname,
399 Error **errp)
400 {
401 NbdClientSession *client = nbd_get_client_session(bs);
402 int ret;
403
404 /* NBD handshake */
405 logout("session init %s\n", export);
406 qio_channel_set_blocking(QIO_CHANNEL(sioc), true, NULL);
407
408 ret = nbd_receive_negotiate(QIO_CHANNEL(sioc), export,
409 &client->nbdflags,
410 tlscreds, hostname,
411 &client->ioc,
412 &client->size, errp);
413 if (ret < 0) {
414 logout("Failed to negotiate with the NBD server\n");
415 return ret;
416 }
417 if (client->nbdflags & NBD_FLAG_SEND_FUA) {
418 bs->supported_write_flags = BDRV_REQ_FUA;
419 }
420
421 qemu_co_mutex_init(&client->send_mutex);
422 qemu_co_mutex_init(&client->free_sema);
423 client->sioc = sioc;
424 object_ref(OBJECT(client->sioc));
425
426 if (!client->ioc) {
427 client->ioc = QIO_CHANNEL(sioc);
428 object_ref(OBJECT(client->ioc));
429 }
430
431 /* Now that we're connected, set the socket to be non-blocking and
432 * kick the reply mechanism. */
433 qio_channel_set_blocking(QIO_CHANNEL(sioc), false, NULL);
434
435 nbd_client_attach_aio_context(bs, bdrv_get_aio_context(bs));
436
437 logout("Established connection with NBD server\n");
438 return 0;
439 }