PPC: e500mc: add missing IVORs to bitmap
[qemu.git] / block / nbd.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-common.h"
30 #include "nbd.h"
31 #include "block_int.h"
32 #include "module.h"
33 #include "qemu_socket.h"
34
35 #include <sys/types.h>
36 #include <unistd.h>
37
38 #define EN_OPTSTR ":exportname="
39
40 /* #define DEBUG_NBD */
41
42 #if defined(DEBUG_NBD)
43 #define logout(fmt, ...) \
44 fprintf(stderr, "nbd\t%-24s" fmt, __func__, ##__VA_ARGS__)
45 #else
46 #define logout(fmt, ...) ((void)0)
47 #endif
48
49 #define MAX_NBD_REQUESTS 16
50 #define HANDLE_TO_INDEX(bs, handle) ((handle) ^ ((uint64_t)(intptr_t)bs))
51 #define INDEX_TO_HANDLE(bs, index) ((index) ^ ((uint64_t)(intptr_t)bs))
52
53 typedef struct BDRVNBDState {
54 int sock;
55 uint32_t nbdflags;
56 off_t size;
57 size_t blocksize;
58 char *export_name; /* An NBD server may export several devices */
59
60 CoMutex send_mutex;
61 CoMutex free_sema;
62 Coroutine *send_coroutine;
63 int in_flight;
64
65 Coroutine *recv_coroutine[MAX_NBD_REQUESTS];
66 struct nbd_reply reply;
67
68 /* If it begins with '/', this is a UNIX domain socket. Otherwise,
69 * it's a string of the form <hostname|ip4|\[ip6\]>:port
70 */
71 char *host_spec;
72 } BDRVNBDState;
73
74 static int nbd_config(BDRVNBDState *s, const char *filename, int flags)
75 {
76 char *file;
77 char *export_name;
78 const char *host_spec;
79 const char *unixpath;
80 int err = -EINVAL;
81
82 file = g_strdup(filename);
83
84 export_name = strstr(file, EN_OPTSTR);
85 if (export_name) {
86 if (export_name[strlen(EN_OPTSTR)] == 0) {
87 goto out;
88 }
89 export_name[0] = 0; /* truncate 'file' */
90 export_name += strlen(EN_OPTSTR);
91 s->export_name = g_strdup(export_name);
92 }
93
94 /* extract the host_spec - fail if it's not nbd:... */
95 if (!strstart(file, "nbd:", &host_spec)) {
96 goto out;
97 }
98
99 /* are we a UNIX or TCP socket? */
100 if (strstart(host_spec, "unix:", &unixpath)) {
101 if (unixpath[0] != '/') { /* We demand an absolute path*/
102 goto out;
103 }
104 s->host_spec = g_strdup(unixpath);
105 } else {
106 s->host_spec = g_strdup(host_spec);
107 }
108
109 err = 0;
110
111 out:
112 g_free(file);
113 if (err != 0) {
114 g_free(s->export_name);
115 g_free(s->host_spec);
116 }
117 return err;
118 }
119
120 static void nbd_coroutine_start(BDRVNBDState *s, struct nbd_request *request)
121 {
122 int i;
123
124 /* Poor man semaphore. The free_sema is locked when no other request
125 * can be accepted, and unlocked after receiving one reply. */
126 if (s->in_flight >= MAX_NBD_REQUESTS - 1) {
127 qemu_co_mutex_lock(&s->free_sema);
128 assert(s->in_flight < MAX_NBD_REQUESTS);
129 }
130 s->in_flight++;
131
132 for (i = 0; i < MAX_NBD_REQUESTS; i++) {
133 if (s->recv_coroutine[i] == NULL) {
134 s->recv_coroutine[i] = qemu_coroutine_self();
135 break;
136 }
137 }
138
139 assert(i < MAX_NBD_REQUESTS);
140 request->handle = INDEX_TO_HANDLE(s, i);
141 }
142
143 static int nbd_have_request(void *opaque)
144 {
145 BDRVNBDState *s = opaque;
146
147 return s->in_flight > 0;
148 }
149
150 static void nbd_reply_ready(void *opaque)
151 {
152 BDRVNBDState *s = opaque;
153 int i;
154
155 if (s->reply.handle == 0) {
156 /* No reply already in flight. Fetch a header. */
157 if (nbd_receive_reply(s->sock, &s->reply) < 0) {
158 s->reply.handle = 0;
159 goto fail;
160 }
161 }
162
163 /* There's no need for a mutex on the receive side, because the
164 * handler acts as a synchronization point and ensures that only
165 * one coroutine is called until the reply finishes. */
166 i = HANDLE_TO_INDEX(s, s->reply.handle);
167 if (s->recv_coroutine[i]) {
168 qemu_coroutine_enter(s->recv_coroutine[i], NULL);
169 return;
170 }
171
172 fail:
173 for (i = 0; i < MAX_NBD_REQUESTS; i++) {
174 if (s->recv_coroutine[i]) {
175 qemu_coroutine_enter(s->recv_coroutine[i], NULL);
176 }
177 }
178 }
179
180 static void nbd_restart_write(void *opaque)
181 {
182 BDRVNBDState *s = opaque;
183 qemu_coroutine_enter(s->send_coroutine, NULL);
184 }
185
186 static int nbd_co_send_request(BDRVNBDState *s, struct nbd_request *request,
187 struct iovec *iov, int offset)
188 {
189 int rc, ret;
190
191 qemu_co_mutex_lock(&s->send_mutex);
192 s->send_coroutine = qemu_coroutine_self();
193 qemu_aio_set_fd_handler(s->sock, nbd_reply_ready, nbd_restart_write,
194 nbd_have_request, NULL, s);
195 rc = nbd_send_request(s->sock, request);
196 if (rc != -1 && iov) {
197 ret = qemu_co_sendv(s->sock, iov, request->len, offset);
198 if (ret != request->len) {
199 errno = -EIO;
200 rc = -1;
201 }
202 }
203 qemu_aio_set_fd_handler(s->sock, nbd_reply_ready, NULL,
204 nbd_have_request, NULL, s);
205 s->send_coroutine = NULL;
206 qemu_co_mutex_unlock(&s->send_mutex);
207 return rc;
208 }
209
210 static void nbd_co_receive_reply(BDRVNBDState *s, struct nbd_request *request,
211 struct nbd_reply *reply,
212 struct iovec *iov, int offset)
213 {
214 int ret;
215
216 /* Wait until we're woken up by the read handler. TODO: perhaps
217 * peek at the next reply and avoid yielding if it's ours? */
218 qemu_coroutine_yield();
219 *reply = s->reply;
220 if (reply->handle != request->handle) {
221 reply->error = EIO;
222 } else {
223 if (iov && reply->error == 0) {
224 ret = qemu_co_recvv(s->sock, iov, request->len, offset);
225 if (ret != request->len) {
226 reply->error = EIO;
227 }
228 }
229
230 /* Tell the read handler to read another header. */
231 s->reply.handle = 0;
232 }
233 }
234
235 static void nbd_coroutine_end(BDRVNBDState *s, struct nbd_request *request)
236 {
237 int i = HANDLE_TO_INDEX(s, request->handle);
238 s->recv_coroutine[i] = NULL;
239 if (s->in_flight-- == MAX_NBD_REQUESTS) {
240 qemu_co_mutex_unlock(&s->free_sema);
241 }
242 }
243
244 static int nbd_establish_connection(BlockDriverState *bs)
245 {
246 BDRVNBDState *s = bs->opaque;
247 int sock;
248 int ret;
249 off_t size;
250 size_t blocksize;
251
252 if (s->host_spec[0] == '/') {
253 sock = unix_socket_outgoing(s->host_spec);
254 } else {
255 sock = tcp_socket_outgoing_spec(s->host_spec);
256 }
257
258 /* Failed to establish connection */
259 if (sock == -1) {
260 logout("Failed to establish connection to NBD server\n");
261 return -errno;
262 }
263
264 /* NBD handshake */
265 ret = nbd_receive_negotiate(sock, s->export_name, &s->nbdflags, &size,
266 &blocksize);
267 if (ret == -1) {
268 logout("Failed to negotiate with the NBD server\n");
269 closesocket(sock);
270 return -errno;
271 }
272
273 /* Now that we're connected, set the socket to be non-blocking and
274 * kick the reply mechanism. */
275 socket_set_nonblock(sock);
276 qemu_aio_set_fd_handler(s->sock, nbd_reply_ready, NULL,
277 nbd_have_request, NULL, s);
278
279 s->sock = sock;
280 s->size = size;
281 s->blocksize = blocksize;
282
283 logout("Established connection with NBD server\n");
284 return 0;
285 }
286
287 static void nbd_teardown_connection(BlockDriverState *bs)
288 {
289 BDRVNBDState *s = bs->opaque;
290 struct nbd_request request;
291
292 request.type = NBD_CMD_DISC;
293 request.from = 0;
294 request.len = 0;
295 nbd_send_request(s->sock, &request);
296
297 qemu_aio_set_fd_handler(s->sock, NULL, NULL, NULL, NULL, NULL);
298 closesocket(s->sock);
299 }
300
301 static int nbd_open(BlockDriverState *bs, const char* filename, int flags)
302 {
303 BDRVNBDState *s = bs->opaque;
304 int result;
305
306 qemu_co_mutex_init(&s->send_mutex);
307 qemu_co_mutex_init(&s->free_sema);
308
309 /* Pop the config into our state object. Exit if invalid. */
310 result = nbd_config(s, filename, flags);
311 if (result != 0) {
312 return result;
313 }
314
315 /* establish TCP connection, return error if it fails
316 * TODO: Configurable retry-until-timeout behaviour.
317 */
318 result = nbd_establish_connection(bs);
319
320 return result;
321 }
322
323 static int nbd_co_readv_1(BlockDriverState *bs, int64_t sector_num,
324 int nb_sectors, QEMUIOVector *qiov,
325 int offset)
326 {
327 BDRVNBDState *s = bs->opaque;
328 struct nbd_request request;
329 struct nbd_reply reply;
330
331 request.type = NBD_CMD_READ;
332 request.from = sector_num * 512;
333 request.len = nb_sectors * 512;
334
335 nbd_coroutine_start(s, &request);
336 if (nbd_co_send_request(s, &request, NULL, 0) == -1) {
337 reply.error = errno;
338 } else {
339 nbd_co_receive_reply(s, &request, &reply, qiov->iov, offset);
340 }
341 nbd_coroutine_end(s, &request);
342 return -reply.error;
343
344 }
345
346 static int nbd_co_writev_1(BlockDriverState *bs, int64_t sector_num,
347 int nb_sectors, QEMUIOVector *qiov,
348 int offset)
349 {
350 BDRVNBDState *s = bs->opaque;
351 struct nbd_request request;
352 struct nbd_reply reply;
353
354 request.type = NBD_CMD_WRITE;
355 if (!bdrv_enable_write_cache(bs) && (s->nbdflags & NBD_FLAG_SEND_FUA)) {
356 request.type |= NBD_CMD_FLAG_FUA;
357 }
358
359 request.from = sector_num * 512;
360 request.len = nb_sectors * 512;
361
362 nbd_coroutine_start(s, &request);
363 if (nbd_co_send_request(s, &request, qiov->iov, offset) == -1) {
364 reply.error = errno;
365 } else {
366 nbd_co_receive_reply(s, &request, &reply, NULL, 0);
367 }
368 nbd_coroutine_end(s, &request);
369 return -reply.error;
370 }
371
372 /* qemu-nbd has a limit of slightly less than 1M per request. Try to
373 * remain aligned to 4K. */
374 #define NBD_MAX_SECTORS 2040
375
376 static int nbd_co_readv(BlockDriverState *bs, int64_t sector_num,
377 int nb_sectors, QEMUIOVector *qiov)
378 {
379 int offset = 0;
380 int ret;
381 while (nb_sectors > NBD_MAX_SECTORS) {
382 ret = nbd_co_readv_1(bs, sector_num, NBD_MAX_SECTORS, qiov, offset);
383 if (ret < 0) {
384 return ret;
385 }
386 offset += NBD_MAX_SECTORS * 512;
387 sector_num += NBD_MAX_SECTORS;
388 nb_sectors -= NBD_MAX_SECTORS;
389 }
390 return nbd_co_readv_1(bs, sector_num, nb_sectors, qiov, offset);
391 }
392
393 static int nbd_co_writev(BlockDriverState *bs, int64_t sector_num,
394 int nb_sectors, QEMUIOVector *qiov)
395 {
396 int offset = 0;
397 int ret;
398 while (nb_sectors > NBD_MAX_SECTORS) {
399 ret = nbd_co_writev_1(bs, sector_num, NBD_MAX_SECTORS, qiov, offset);
400 if (ret < 0) {
401 return ret;
402 }
403 offset += NBD_MAX_SECTORS * 512;
404 sector_num += NBD_MAX_SECTORS;
405 nb_sectors -= NBD_MAX_SECTORS;
406 }
407 return nbd_co_writev_1(bs, sector_num, nb_sectors, qiov, offset);
408 }
409
410 static int nbd_co_flush(BlockDriverState *bs)
411 {
412 BDRVNBDState *s = bs->opaque;
413 struct nbd_request request;
414 struct nbd_reply reply;
415
416 if (!(s->nbdflags & NBD_FLAG_SEND_FLUSH)) {
417 return 0;
418 }
419
420 request.type = NBD_CMD_FLUSH;
421 if (s->nbdflags & NBD_FLAG_SEND_FUA) {
422 request.type |= NBD_CMD_FLAG_FUA;
423 }
424
425 request.from = 0;
426 request.len = 0;
427
428 nbd_coroutine_start(s, &request);
429 if (nbd_co_send_request(s, &request, NULL, 0) == -1) {
430 reply.error = errno;
431 } else {
432 nbd_co_receive_reply(s, &request, &reply, NULL, 0);
433 }
434 nbd_coroutine_end(s, &request);
435 return -reply.error;
436 }
437
438 static int nbd_co_discard(BlockDriverState *bs, int64_t sector_num,
439 int nb_sectors)
440 {
441 BDRVNBDState *s = bs->opaque;
442 struct nbd_request request;
443 struct nbd_reply reply;
444
445 if (!(s->nbdflags & NBD_FLAG_SEND_TRIM)) {
446 return 0;
447 }
448 request.type = NBD_CMD_TRIM;
449 request.from = sector_num * 512;;
450 request.len = nb_sectors * 512;
451
452 nbd_coroutine_start(s, &request);
453 if (nbd_co_send_request(s, &request, NULL, 0) == -1) {
454 reply.error = errno;
455 } else {
456 nbd_co_receive_reply(s, &request, &reply, NULL, 0);
457 }
458 nbd_coroutine_end(s, &request);
459 return -reply.error;
460 }
461
462 static void nbd_close(BlockDriverState *bs)
463 {
464 BDRVNBDState *s = bs->opaque;
465 g_free(s->export_name);
466 g_free(s->host_spec);
467
468 nbd_teardown_connection(bs);
469 }
470
471 static int64_t nbd_getlength(BlockDriverState *bs)
472 {
473 BDRVNBDState *s = bs->opaque;
474
475 return s->size;
476 }
477
478 static BlockDriver bdrv_nbd = {
479 .format_name = "nbd",
480 .instance_size = sizeof(BDRVNBDState),
481 .bdrv_file_open = nbd_open,
482 .bdrv_co_readv = nbd_co_readv,
483 .bdrv_co_writev = nbd_co_writev,
484 .bdrv_close = nbd_close,
485 .bdrv_co_flush_to_os = nbd_co_flush,
486 .bdrv_co_discard = nbd_co_discard,
487 .bdrv_getlength = nbd_getlength,
488 .protocol_name = "nbd",
489 };
490
491 static void bdrv_nbd_init(void)
492 {
493 bdrv_register(&bdrv_nbd);
494 }
495
496 block_init(bdrv_nbd_init);