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30#include "qemu/osdep.h"
31#include "qapi/error.h"
32#include "nbd-client.h"
33
34#define HANDLE_TO_INDEX(bs, handle) ((handle) ^ ((uint64_t)(intptr_t)bs))
35#define INDEX_TO_HANDLE(bs, index) ((index) ^ ((uint64_t)(intptr_t)bs))
36
37static void nbd_recv_coroutines_enter_all(NBDClientSession *s)
38{
39 int i;
40
41 for (i = 0; i < MAX_NBD_REQUESTS; i++) {
42 NBDClientRequest *req = &s->requests[i];
43
44 if (req->coroutine && req->receiving) {
45 aio_co_wake(req->coroutine);
46 }
47 }
48}
49
50static void nbd_teardown_connection(BlockDriverState *bs)
51{
52 NBDClientSession *client = nbd_get_client_session(bs);
53
54 if (!client->ioc) {
55 return;
56 }
57
58
59 qio_channel_shutdown(client->ioc,
60 QIO_CHANNEL_SHUTDOWN_BOTH,
61 NULL);
62 BDRV_POLL_WHILE(bs, client->read_reply_co);
63
64 nbd_client_detach_aio_context(bs);
65 object_unref(OBJECT(client->sioc));
66 client->sioc = NULL;
67 object_unref(OBJECT(client->ioc));
68 client->ioc = NULL;
69}
70
71static coroutine_fn void nbd_read_reply_entry(void *opaque)
72{
73 NBDClientSession *s = opaque;
74 uint64_t i;
75 int ret = 0;
76 Error *local_err = NULL;
77
78 while (!s->quit) {
79 assert(s->reply.handle == 0);
80 ret = nbd_receive_reply(s->ioc, &s->reply, &local_err);
81 if (ret < 0) {
82 error_report_err(local_err);
83 }
84 if (ret <= 0) {
85 break;
86 }
87
88
89
90
91
92 i = HANDLE_TO_INDEX(s, s->reply.handle);
93 if (i >= MAX_NBD_REQUESTS ||
94 !s->requests[i].coroutine ||
95 !s->requests[i].receiving) {
96 break;
97 }
98
99
100
101
102
103
104
105
106
107
108
109
110 aio_co_wake(s->requests[i].coroutine);
111 qemu_coroutine_yield();
112 }
113
114 s->quit = true;
115 nbd_recv_coroutines_enter_all(s);
116 s->read_reply_co = NULL;
117}
118
119static int nbd_co_send_request(BlockDriverState *bs,
120 NBDRequest *request,
121 QEMUIOVector *qiov)
122{
123 NBDClientSession *s = nbd_get_client_session(bs);
124 int rc, ret, i;
125
126 qemu_co_mutex_lock(&s->send_mutex);
127 while (s->in_flight == MAX_NBD_REQUESTS) {
128 qemu_co_queue_wait(&s->free_sema, &s->send_mutex);
129 }
130 s->in_flight++;
131
132 for (i = 0; i < MAX_NBD_REQUESTS; i++) {
133 if (s->requests[i].coroutine == NULL) {
134 break;
135 }
136 }
137
138 g_assert(qemu_in_coroutine());
139 assert(i < MAX_NBD_REQUESTS);
140
141 s->requests[i].coroutine = qemu_coroutine_self();
142 s->requests[i].receiving = false;
143
144 request->handle = INDEX_TO_HANDLE(s, i);
145
146 if (s->quit) {
147 rc = -EIO;
148 goto err;
149 }
150 if (!s->ioc) {
151 rc = -EPIPE;
152 goto err;
153 }
154
155 if (qiov) {
156 qio_channel_set_cork(s->ioc, true);
157 rc = nbd_send_request(s->ioc, request);
158 if (rc >= 0 && !s->quit) {
159 ret = nbd_rwv(s->ioc, qiov->iov, qiov->niov, request->len, false,
160 NULL);
161 if (ret != request->len) {
162 rc = -EIO;
163 }
164 }
165 qio_channel_set_cork(s->ioc, false);
166 } else {
167 rc = nbd_send_request(s->ioc, request);
168 }
169
170err:
171 if (rc < 0) {
172 s->quit = true;
173 s->requests[i].coroutine = NULL;
174 s->in_flight--;
175 qemu_co_queue_next(&s->free_sema);
176 }
177 qemu_co_mutex_unlock(&s->send_mutex);
178 return rc;
179}
180
181static void nbd_co_receive_reply(NBDClientSession *s,
182 NBDRequest *request,
183 NBDReply *reply,
184 QEMUIOVector *qiov)
185{
186 int i = HANDLE_TO_INDEX(s, request->handle);
187 int ret;
188
189
190 s->requests[i].receiving = true;
191 qemu_coroutine_yield();
192 s->requests[i].receiving = false;
193 *reply = s->reply;
194 if (reply->handle != request->handle || !s->ioc || s->quit) {
195 reply->error = EIO;
196 } else {
197 if (qiov && reply->error == 0) {
198 ret = nbd_rwv(s->ioc, qiov->iov, qiov->niov, request->len, true,
199 NULL);
200 if (ret != request->len) {
201 reply->error = EIO;
202 s->quit = true;
203 }
204 }
205
206
207 s->reply.handle = 0;
208 }
209
210 s->requests[i].coroutine = NULL;
211
212
213 if (s->read_reply_co) {
214 aio_co_wake(s->read_reply_co);
215 }
216
217 qemu_co_mutex_lock(&s->send_mutex);
218 s->in_flight--;
219 qemu_co_queue_next(&s->free_sema);
220 qemu_co_mutex_unlock(&s->send_mutex);
221}
222
223int nbd_client_co_preadv(BlockDriverState *bs, uint64_t offset,
224 uint64_t bytes, QEMUIOVector *qiov, int flags)
225{
226 NBDClientSession *client = nbd_get_client_session(bs);
227 NBDRequest request = {
228 .type = NBD_CMD_READ,
229 .from = offset,
230 .len = bytes,
231 };
232 NBDReply reply;
233 ssize_t ret;
234
235 assert(bytes <= NBD_MAX_BUFFER_SIZE);
236 assert(!flags);
237
238 ret = nbd_co_send_request(bs, &request, NULL);
239 if (ret < 0) {
240 reply.error = -ret;
241 } else {
242 nbd_co_receive_reply(client, &request, &reply, qiov);
243 }
244 return -reply.error;
245}
246
247int nbd_client_co_pwritev(BlockDriverState *bs, uint64_t offset,
248 uint64_t bytes, QEMUIOVector *qiov, int flags)
249{
250 NBDClientSession *client = nbd_get_client_session(bs);
251 NBDRequest request = {
252 .type = NBD_CMD_WRITE,
253 .from = offset,
254 .len = bytes,
255 };
256 NBDReply reply;
257 ssize_t ret;
258
259 assert(!(client->info.flags & NBD_FLAG_READ_ONLY));
260 if (flags & BDRV_REQ_FUA) {
261 assert(client->info.flags & NBD_FLAG_SEND_FUA);
262 request.flags |= NBD_CMD_FLAG_FUA;
263 }
264
265 assert(bytes <= NBD_MAX_BUFFER_SIZE);
266
267 ret = nbd_co_send_request(bs, &request, qiov);
268 if (ret < 0) {
269 reply.error = -ret;
270 } else {
271 nbd_co_receive_reply(client, &request, &reply, NULL);
272 }
273 return -reply.error;
274}
275
276int nbd_client_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset,
277 int bytes, BdrvRequestFlags flags)
278{
279 ssize_t ret;
280 NBDClientSession *client = nbd_get_client_session(bs);
281 NBDRequest request = {
282 .type = NBD_CMD_WRITE_ZEROES,
283 .from = offset,
284 .len = bytes,
285 };
286 NBDReply reply;
287
288 assert(!(client->info.flags & NBD_FLAG_READ_ONLY));
289 if (!(client->info.flags & NBD_FLAG_SEND_WRITE_ZEROES)) {
290 return -ENOTSUP;
291 }
292
293 if (flags & BDRV_REQ_FUA) {
294 assert(client->info.flags & NBD_FLAG_SEND_FUA);
295 request.flags |= NBD_CMD_FLAG_FUA;
296 }
297 if (!(flags & BDRV_REQ_MAY_UNMAP)) {
298 request.flags |= NBD_CMD_FLAG_NO_HOLE;
299 }
300
301 ret = nbd_co_send_request(bs, &request, NULL);
302 if (ret < 0) {
303 reply.error = -ret;
304 } else {
305 nbd_co_receive_reply(client, &request, &reply, NULL);
306 }
307 return -reply.error;
308}
309
310int nbd_client_co_flush(BlockDriverState *bs)
311{
312 NBDClientSession *client = nbd_get_client_session(bs);
313 NBDRequest request = { .type = NBD_CMD_FLUSH };
314 NBDReply reply;
315 ssize_t ret;
316
317 if (!(client->info.flags & NBD_FLAG_SEND_FLUSH)) {
318 return 0;
319 }
320
321 request.from = 0;
322 request.len = 0;
323
324 ret = nbd_co_send_request(bs, &request, NULL);
325 if (ret < 0) {
326 reply.error = -ret;
327 } else {
328 nbd_co_receive_reply(client, &request, &reply, NULL);
329 }
330 return -reply.error;
331}
332
333int nbd_client_co_pdiscard(BlockDriverState *bs, int64_t offset, int bytes)
334{
335 NBDClientSession *client = nbd_get_client_session(bs);
336 NBDRequest request = {
337 .type = NBD_CMD_TRIM,
338 .from = offset,
339 .len = bytes,
340 };
341 NBDReply reply;
342 ssize_t ret;
343
344 assert(!(client->info.flags & NBD_FLAG_READ_ONLY));
345 if (!(client->info.flags & NBD_FLAG_SEND_TRIM)) {
346 return 0;
347 }
348
349 ret = nbd_co_send_request(bs, &request, NULL);
350 if (ret < 0) {
351 reply.error = -ret;
352 } else {
353 nbd_co_receive_reply(client, &request, &reply, NULL);
354 }
355 return -reply.error;
356
357}
358
359void nbd_client_detach_aio_context(BlockDriverState *bs)
360{
361 NBDClientSession *client = nbd_get_client_session(bs);
362 qio_channel_detach_aio_context(QIO_CHANNEL(client->ioc));
363}
364
365void nbd_client_attach_aio_context(BlockDriverState *bs,
366 AioContext *new_context)
367{
368 NBDClientSession *client = nbd_get_client_session(bs);
369 qio_channel_attach_aio_context(QIO_CHANNEL(client->ioc), new_context);
370 aio_co_schedule(new_context, client->read_reply_co);
371}
372
373void nbd_client_close(BlockDriverState *bs)
374{
375 NBDClientSession *client = nbd_get_client_session(bs);
376 NBDRequest request = { .type = NBD_CMD_DISC };
377
378 if (client->ioc == NULL) {
379 return;
380 }
381
382 nbd_send_request(client->ioc, &request);
383
384 nbd_teardown_connection(bs);
385}
386
387int nbd_client_init(BlockDriverState *bs,
388 QIOChannelSocket *sioc,
389 const char *export,
390 QCryptoTLSCreds *tlscreds,
391 const char *hostname,
392 Error **errp)
393{
394 NBDClientSession *client = nbd_get_client_session(bs);
395 int ret;
396
397
398 logout("session init %s\n", export);
399 qio_channel_set_blocking(QIO_CHANNEL(sioc), true, NULL);
400
401 client->info.request_sizes = true;
402 ret = nbd_receive_negotiate(QIO_CHANNEL(sioc), export,
403 tlscreds, hostname,
404 &client->ioc, &client->info, errp);
405 if (ret < 0) {
406 logout("Failed to negotiate with the NBD server\n");
407 return ret;
408 }
409 if (client->info.flags & NBD_FLAG_READ_ONLY &&
410 !bdrv_is_read_only(bs)) {
411 error_setg(errp,
412 "request for write access conflicts with read-only export");
413 return -EACCES;
414 }
415 if (client->info.flags & NBD_FLAG_SEND_FUA) {
416 bs->supported_write_flags = BDRV_REQ_FUA;
417 bs->supported_zero_flags |= BDRV_REQ_FUA;
418 }
419 if (client->info.flags & NBD_FLAG_SEND_WRITE_ZEROES) {
420 bs->supported_zero_flags |= BDRV_REQ_MAY_UNMAP;
421 }
422 if (client->info.min_block > bs->bl.request_alignment) {
423 bs->bl.request_alignment = client->info.min_block;
424 }
425
426 qemu_co_mutex_init(&client->send_mutex);
427 qemu_co_queue_init(&client->free_sema);
428 client->sioc = sioc;
429 object_ref(OBJECT(client->sioc));
430
431 if (!client->ioc) {
432 client->ioc = QIO_CHANNEL(sioc);
433 object_ref(OBJECT(client->ioc));
434 }
435
436
437
438 qio_channel_set_blocking(QIO_CHANNEL(sioc), false, NULL);
439 client->read_reply_co = qemu_coroutine_create(nbd_read_reply_entry, client);
440 nbd_client_attach_aio_context(bs, bdrv_get_aio_context(bs));
441
442 logout("Established connection with NBD server\n");
443 return 0;
444}
445