]>
Commit | Line | Data |
---|---|---|
1 | /* | |
2 | * Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws> | |
3 | * | |
4 | * Network Block Device | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; under version 2 of the License. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License | |
16 | * along with this program; if not, see <http://www.gnu.org/licenses/>. | |
17 | */ | |
18 | ||
19 | #include "block/nbd.h" | |
20 | #include "block/block.h" | |
21 | ||
22 | #include "block/coroutine.h" | |
23 | ||
24 | #include <errno.h> | |
25 | #include <string.h> | |
26 | #ifndef _WIN32 | |
27 | #include <sys/ioctl.h> | |
28 | #endif | |
29 | #if defined(__sun__) || defined(__HAIKU__) | |
30 | #include <sys/ioccom.h> | |
31 | #endif | |
32 | #include <ctype.h> | |
33 | #include <inttypes.h> | |
34 | ||
35 | #ifdef __linux__ | |
36 | #include <linux/fs.h> | |
37 | #endif | |
38 | ||
39 | #include "qemu_socket.h" | |
40 | #include "qemu-queue.h" | |
41 | ||
42 | //#define DEBUG_NBD | |
43 | ||
44 | #ifdef DEBUG_NBD | |
45 | #define TRACE(msg, ...) do { \ | |
46 | LOG(msg, ## __VA_ARGS__); \ | |
47 | } while(0) | |
48 | #else | |
49 | #define TRACE(msg, ...) \ | |
50 | do { } while (0) | |
51 | #endif | |
52 | ||
53 | #define LOG(msg, ...) do { \ | |
54 | fprintf(stderr, "%s:%s():L%d: " msg "\n", \ | |
55 | __FILE__, __FUNCTION__, __LINE__, ## __VA_ARGS__); \ | |
56 | } while(0) | |
57 | ||
58 | /* This is all part of the "official" NBD API */ | |
59 | ||
60 | #define NBD_REQUEST_SIZE (4 + 4 + 8 + 8 + 4) | |
61 | #define NBD_REPLY_SIZE (4 + 4 + 8) | |
62 | #define NBD_REQUEST_MAGIC 0x25609513 | |
63 | #define NBD_REPLY_MAGIC 0x67446698 | |
64 | #define NBD_OPTS_MAGIC 0x49484156454F5054LL | |
65 | #define NBD_CLIENT_MAGIC 0x0000420281861253LL | |
66 | ||
67 | #define NBD_SET_SOCK _IO(0xab, 0) | |
68 | #define NBD_SET_BLKSIZE _IO(0xab, 1) | |
69 | #define NBD_SET_SIZE _IO(0xab, 2) | |
70 | #define NBD_DO_IT _IO(0xab, 3) | |
71 | #define NBD_CLEAR_SOCK _IO(0xab, 4) | |
72 | #define NBD_CLEAR_QUE _IO(0xab, 5) | |
73 | #define NBD_PRINT_DEBUG _IO(0xab, 6) | |
74 | #define NBD_SET_SIZE_BLOCKS _IO(0xab, 7) | |
75 | #define NBD_DISCONNECT _IO(0xab, 8) | |
76 | #define NBD_SET_TIMEOUT _IO(0xab, 9) | |
77 | #define NBD_SET_FLAGS _IO(0xab, 10) | |
78 | ||
79 | #define NBD_OPT_EXPORT_NAME (1 << 0) | |
80 | ||
81 | /* Definitions for opaque data types */ | |
82 | ||
83 | typedef struct NBDRequest NBDRequest; | |
84 | ||
85 | struct NBDRequest { | |
86 | QSIMPLEQ_ENTRY(NBDRequest) entry; | |
87 | NBDClient *client; | |
88 | uint8_t *data; | |
89 | }; | |
90 | ||
91 | struct NBDExport { | |
92 | int refcount; | |
93 | void (*close)(NBDExport *exp); | |
94 | ||
95 | BlockDriverState *bs; | |
96 | char *name; | |
97 | off_t dev_offset; | |
98 | off_t size; | |
99 | uint32_t nbdflags; | |
100 | QTAILQ_HEAD(, NBDClient) clients; | |
101 | QSIMPLEQ_HEAD(, NBDRequest) requests; | |
102 | QTAILQ_ENTRY(NBDExport) next; | |
103 | }; | |
104 | ||
105 | static QTAILQ_HEAD(, NBDExport) exports = QTAILQ_HEAD_INITIALIZER(exports); | |
106 | ||
107 | struct NBDClient { | |
108 | int refcount; | |
109 | void (*close)(NBDClient *client); | |
110 | ||
111 | NBDExport *exp; | |
112 | int sock; | |
113 | ||
114 | Coroutine *recv_coroutine; | |
115 | ||
116 | CoMutex send_lock; | |
117 | Coroutine *send_coroutine; | |
118 | ||
119 | QTAILQ_ENTRY(NBDClient) next; | |
120 | int nb_requests; | |
121 | bool closing; | |
122 | }; | |
123 | ||
124 | /* That's all folks */ | |
125 | ||
126 | ssize_t nbd_wr_sync(int fd, void *buffer, size_t size, bool do_read) | |
127 | { | |
128 | size_t offset = 0; | |
129 | int err; | |
130 | ||
131 | if (qemu_in_coroutine()) { | |
132 | if (do_read) { | |
133 | return qemu_co_recv(fd, buffer, size); | |
134 | } else { | |
135 | return qemu_co_send(fd, buffer, size); | |
136 | } | |
137 | } | |
138 | ||
139 | while (offset < size) { | |
140 | ssize_t len; | |
141 | ||
142 | if (do_read) { | |
143 | len = qemu_recv(fd, buffer + offset, size - offset, 0); | |
144 | } else { | |
145 | len = send(fd, buffer + offset, size - offset, 0); | |
146 | } | |
147 | ||
148 | if (len < 0) { | |
149 | err = socket_error(); | |
150 | ||
151 | /* recoverable error */ | |
152 | if (err == EINTR || (offset > 0 && err == EAGAIN)) { | |
153 | continue; | |
154 | } | |
155 | ||
156 | /* unrecoverable error */ | |
157 | return -err; | |
158 | } | |
159 | ||
160 | /* eof */ | |
161 | if (len == 0) { | |
162 | break; | |
163 | } | |
164 | ||
165 | offset += len; | |
166 | } | |
167 | ||
168 | return offset; | |
169 | } | |
170 | ||
171 | static ssize_t read_sync(int fd, void *buffer, size_t size) | |
172 | { | |
173 | /* Sockets are kept in blocking mode in the negotiation phase. After | |
174 | * that, a non-readable socket simply means that another thread stole | |
175 | * our request/reply. Synchronization is done with recv_coroutine, so | |
176 | * that this is coroutine-safe. | |
177 | */ | |
178 | return nbd_wr_sync(fd, buffer, size, true); | |
179 | } | |
180 | ||
181 | static ssize_t write_sync(int fd, void *buffer, size_t size) | |
182 | { | |
183 | int ret; | |
184 | do { | |
185 | /* For writes, we do expect the socket to be writable. */ | |
186 | ret = nbd_wr_sync(fd, buffer, size, false); | |
187 | } while (ret == -EAGAIN); | |
188 | return ret; | |
189 | } | |
190 | ||
191 | static void combine_addr(char *buf, size_t len, const char* address, | |
192 | uint16_t port) | |
193 | { | |
194 | /* If the address-part contains a colon, it's an IPv6 IP so needs [] */ | |
195 | if (strstr(address, ":")) { | |
196 | snprintf(buf, len, "[%s]:%u", address, port); | |
197 | } else { | |
198 | snprintf(buf, len, "%s:%u", address, port); | |
199 | } | |
200 | } | |
201 | ||
202 | int tcp_socket_outgoing(const char *address, uint16_t port) | |
203 | { | |
204 | char address_and_port[128]; | |
205 | combine_addr(address_and_port, 128, address, port); | |
206 | return tcp_socket_outgoing_spec(address_and_port); | |
207 | } | |
208 | ||
209 | int tcp_socket_outgoing_spec(const char *address_and_port) | |
210 | { | |
211 | Error *local_err = NULL; | |
212 | int fd = inet_connect(address_and_port, &local_err); | |
213 | ||
214 | if (local_err != NULL) { | |
215 | qerror_report_err(local_err); | |
216 | error_free(local_err); | |
217 | } | |
218 | return fd; | |
219 | } | |
220 | ||
221 | int tcp_socket_incoming(const char *address, uint16_t port) | |
222 | { | |
223 | char address_and_port[128]; | |
224 | combine_addr(address_and_port, 128, address, port); | |
225 | return tcp_socket_incoming_spec(address_and_port); | |
226 | } | |
227 | ||
228 | int tcp_socket_incoming_spec(const char *address_and_port) | |
229 | { | |
230 | Error *local_err = NULL; | |
231 | int fd = inet_listen(address_and_port, NULL, 0, SOCK_STREAM, 0, &local_err); | |
232 | ||
233 | if (local_err != NULL) { | |
234 | qerror_report_err(local_err); | |
235 | error_free(local_err); | |
236 | } | |
237 | return fd; | |
238 | } | |
239 | ||
240 | int unix_socket_incoming(const char *path) | |
241 | { | |
242 | Error *local_err = NULL; | |
243 | int fd = unix_listen(path, NULL, 0, &local_err); | |
244 | ||
245 | if (local_err != NULL) { | |
246 | qerror_report_err(local_err); | |
247 | error_free(local_err); | |
248 | } | |
249 | return fd; | |
250 | } | |
251 | ||
252 | int unix_socket_outgoing(const char *path) | |
253 | { | |
254 | Error *local_err = NULL; | |
255 | int fd = unix_connect(path, &local_err); | |
256 | ||
257 | if (local_err != NULL) { | |
258 | qerror_report_err(local_err); | |
259 | error_free(local_err); | |
260 | } | |
261 | return fd; | |
262 | } | |
263 | ||
264 | /* Basic flow for negotiation | |
265 | ||
266 | Server Client | |
267 | Negotiate | |
268 | ||
269 | or | |
270 | ||
271 | Server Client | |
272 | Negotiate #1 | |
273 | Option | |
274 | Negotiate #2 | |
275 | ||
276 | ---- | |
277 | ||
278 | followed by | |
279 | ||
280 | Server Client | |
281 | Request | |
282 | Response | |
283 | Request | |
284 | Response | |
285 | ... | |
286 | ... | |
287 | Request (type == 2) | |
288 | ||
289 | */ | |
290 | ||
291 | static int nbd_receive_options(NBDClient *client) | |
292 | { | |
293 | int csock = client->sock; | |
294 | char name[256]; | |
295 | uint32_t tmp, length; | |
296 | uint64_t magic; | |
297 | int rc; | |
298 | ||
299 | /* Client sends: | |
300 | [ 0 .. 3] reserved (0) | |
301 | [ 4 .. 11] NBD_OPTS_MAGIC | |
302 | [12 .. 15] NBD_OPT_EXPORT_NAME | |
303 | [16 .. 19] length | |
304 | [20 .. xx] export name (length bytes) | |
305 | */ | |
306 | ||
307 | rc = -EINVAL; | |
308 | if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) { | |
309 | LOG("read failed"); | |
310 | goto fail; | |
311 | } | |
312 | TRACE("Checking reserved"); | |
313 | if (tmp != 0) { | |
314 | LOG("Bad reserved received"); | |
315 | goto fail; | |
316 | } | |
317 | ||
318 | if (read_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) { | |
319 | LOG("read failed"); | |
320 | goto fail; | |
321 | } | |
322 | TRACE("Checking reserved"); | |
323 | if (magic != be64_to_cpu(NBD_OPTS_MAGIC)) { | |
324 | LOG("Bad magic received"); | |
325 | goto fail; | |
326 | } | |
327 | ||
328 | if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) { | |
329 | LOG("read failed"); | |
330 | goto fail; | |
331 | } | |
332 | TRACE("Checking option"); | |
333 | if (tmp != be32_to_cpu(NBD_OPT_EXPORT_NAME)) { | |
334 | LOG("Bad option received"); | |
335 | goto fail; | |
336 | } | |
337 | ||
338 | if (read_sync(csock, &length, sizeof(length)) != sizeof(length)) { | |
339 | LOG("read failed"); | |
340 | goto fail; | |
341 | } | |
342 | TRACE("Checking length"); | |
343 | length = be32_to_cpu(length); | |
344 | if (length > 255) { | |
345 | LOG("Bad length received"); | |
346 | goto fail; | |
347 | } | |
348 | if (read_sync(csock, name, length) != length) { | |
349 | LOG("read failed"); | |
350 | goto fail; | |
351 | } | |
352 | name[length] = '\0'; | |
353 | ||
354 | client->exp = nbd_export_find(name); | |
355 | if (!client->exp) { | |
356 | LOG("export not found"); | |
357 | goto fail; | |
358 | } | |
359 | ||
360 | QTAILQ_INSERT_TAIL(&client->exp->clients, client, next); | |
361 | nbd_export_get(client->exp); | |
362 | ||
363 | TRACE("Option negotiation succeeded."); | |
364 | rc = 0; | |
365 | fail: | |
366 | return rc; | |
367 | } | |
368 | ||
369 | static int nbd_send_negotiate(NBDClient *client) | |
370 | { | |
371 | int csock = client->sock; | |
372 | char buf[8 + 8 + 8 + 128]; | |
373 | int rc; | |
374 | const int myflags = (NBD_FLAG_HAS_FLAGS | NBD_FLAG_SEND_TRIM | | |
375 | NBD_FLAG_SEND_FLUSH | NBD_FLAG_SEND_FUA); | |
376 | ||
377 | /* Negotiation header without options: | |
378 | [ 0 .. 7] passwd ("NBDMAGIC") | |
379 | [ 8 .. 15] magic (NBD_CLIENT_MAGIC) | |
380 | [16 .. 23] size | |
381 | [24 .. 25] server flags (0) | |
382 | [24 .. 27] export flags | |
383 | [28 .. 151] reserved (0) | |
384 | ||
385 | Negotiation header with options, part 1: | |
386 | [ 0 .. 7] passwd ("NBDMAGIC") | |
387 | [ 8 .. 15] magic (NBD_OPTS_MAGIC) | |
388 | [16 .. 17] server flags (0) | |
389 | ||
390 | part 2 (after options are sent): | |
391 | [18 .. 25] size | |
392 | [26 .. 27] export flags | |
393 | [28 .. 151] reserved (0) | |
394 | */ | |
395 | ||
396 | socket_set_block(csock); | |
397 | rc = -EINVAL; | |
398 | ||
399 | TRACE("Beginning negotiation."); | |
400 | memset(buf, 0, sizeof(buf)); | |
401 | memcpy(buf, "NBDMAGIC", 8); | |
402 | if (client->exp) { | |
403 | assert ((client->exp->nbdflags & ~65535) == 0); | |
404 | cpu_to_be64w((uint64_t*)(buf + 8), NBD_CLIENT_MAGIC); | |
405 | cpu_to_be64w((uint64_t*)(buf + 16), client->exp->size); | |
406 | cpu_to_be16w((uint16_t*)(buf + 26), client->exp->nbdflags | myflags); | |
407 | } else { | |
408 | cpu_to_be64w((uint64_t*)(buf + 8), NBD_OPTS_MAGIC); | |
409 | } | |
410 | ||
411 | if (client->exp) { | |
412 | if (write_sync(csock, buf, sizeof(buf)) != sizeof(buf)) { | |
413 | LOG("write failed"); | |
414 | goto fail; | |
415 | } | |
416 | } else { | |
417 | if (write_sync(csock, buf, 18) != 18) { | |
418 | LOG("write failed"); | |
419 | goto fail; | |
420 | } | |
421 | rc = nbd_receive_options(client); | |
422 | if (rc < 0) { | |
423 | LOG("option negotiation failed"); | |
424 | goto fail; | |
425 | } | |
426 | ||
427 | assert ((client->exp->nbdflags & ~65535) == 0); | |
428 | cpu_to_be64w((uint64_t*)(buf + 18), client->exp->size); | |
429 | cpu_to_be16w((uint16_t*)(buf + 26), client->exp->nbdflags | myflags); | |
430 | if (write_sync(csock, buf + 18, sizeof(buf) - 18) != sizeof(buf) - 18) { | |
431 | LOG("write failed"); | |
432 | goto fail; | |
433 | } | |
434 | } | |
435 | ||
436 | TRACE("Negotiation succeeded."); | |
437 | rc = 0; | |
438 | fail: | |
439 | socket_set_nonblock(csock); | |
440 | return rc; | |
441 | } | |
442 | ||
443 | int nbd_receive_negotiate(int csock, const char *name, uint32_t *flags, | |
444 | off_t *size, size_t *blocksize) | |
445 | { | |
446 | char buf[256]; | |
447 | uint64_t magic, s; | |
448 | uint16_t tmp; | |
449 | int rc; | |
450 | ||
451 | TRACE("Receiving negotiation."); | |
452 | ||
453 | socket_set_block(csock); | |
454 | rc = -EINVAL; | |
455 | ||
456 | if (read_sync(csock, buf, 8) != 8) { | |
457 | LOG("read failed"); | |
458 | goto fail; | |
459 | } | |
460 | ||
461 | buf[8] = '\0'; | |
462 | if (strlen(buf) == 0) { | |
463 | LOG("server connection closed"); | |
464 | goto fail; | |
465 | } | |
466 | ||
467 | TRACE("Magic is %c%c%c%c%c%c%c%c", | |
468 | qemu_isprint(buf[0]) ? buf[0] : '.', | |
469 | qemu_isprint(buf[1]) ? buf[1] : '.', | |
470 | qemu_isprint(buf[2]) ? buf[2] : '.', | |
471 | qemu_isprint(buf[3]) ? buf[3] : '.', | |
472 | qemu_isprint(buf[4]) ? buf[4] : '.', | |
473 | qemu_isprint(buf[5]) ? buf[5] : '.', | |
474 | qemu_isprint(buf[6]) ? buf[6] : '.', | |
475 | qemu_isprint(buf[7]) ? buf[7] : '.'); | |
476 | ||
477 | if (memcmp(buf, "NBDMAGIC", 8) != 0) { | |
478 | LOG("Invalid magic received"); | |
479 | goto fail; | |
480 | } | |
481 | ||
482 | if (read_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) { | |
483 | LOG("read failed"); | |
484 | goto fail; | |
485 | } | |
486 | magic = be64_to_cpu(magic); | |
487 | TRACE("Magic is 0x%" PRIx64, magic); | |
488 | ||
489 | if (name) { | |
490 | uint32_t reserved = 0; | |
491 | uint32_t opt; | |
492 | uint32_t namesize; | |
493 | ||
494 | TRACE("Checking magic (opts_magic)"); | |
495 | if (magic != NBD_OPTS_MAGIC) { | |
496 | LOG("Bad magic received"); | |
497 | goto fail; | |
498 | } | |
499 | if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) { | |
500 | LOG("flags read failed"); | |
501 | goto fail; | |
502 | } | |
503 | *flags = be16_to_cpu(tmp) << 16; | |
504 | /* reserved for future use */ | |
505 | if (write_sync(csock, &reserved, sizeof(reserved)) != | |
506 | sizeof(reserved)) { | |
507 | LOG("write failed (reserved)"); | |
508 | goto fail; | |
509 | } | |
510 | /* write the export name */ | |
511 | magic = cpu_to_be64(magic); | |
512 | if (write_sync(csock, &magic, sizeof(magic)) != sizeof(magic)) { | |
513 | LOG("write failed (magic)"); | |
514 | goto fail; | |
515 | } | |
516 | opt = cpu_to_be32(NBD_OPT_EXPORT_NAME); | |
517 | if (write_sync(csock, &opt, sizeof(opt)) != sizeof(opt)) { | |
518 | LOG("write failed (opt)"); | |
519 | goto fail; | |
520 | } | |
521 | namesize = cpu_to_be32(strlen(name)); | |
522 | if (write_sync(csock, &namesize, sizeof(namesize)) != | |
523 | sizeof(namesize)) { | |
524 | LOG("write failed (namesize)"); | |
525 | goto fail; | |
526 | } | |
527 | if (write_sync(csock, (char*)name, strlen(name)) != strlen(name)) { | |
528 | LOG("write failed (name)"); | |
529 | goto fail; | |
530 | } | |
531 | } else { | |
532 | TRACE("Checking magic (cli_magic)"); | |
533 | ||
534 | if (magic != NBD_CLIENT_MAGIC) { | |
535 | LOG("Bad magic received"); | |
536 | goto fail; | |
537 | } | |
538 | } | |
539 | ||
540 | if (read_sync(csock, &s, sizeof(s)) != sizeof(s)) { | |
541 | LOG("read failed"); | |
542 | goto fail; | |
543 | } | |
544 | *size = be64_to_cpu(s); | |
545 | *blocksize = 1024; | |
546 | TRACE("Size is %" PRIu64, *size); | |
547 | ||
548 | if (!name) { | |
549 | if (read_sync(csock, flags, sizeof(*flags)) != sizeof(*flags)) { | |
550 | LOG("read failed (flags)"); | |
551 | goto fail; | |
552 | } | |
553 | *flags = be32_to_cpup(flags); | |
554 | } else { | |
555 | if (read_sync(csock, &tmp, sizeof(tmp)) != sizeof(tmp)) { | |
556 | LOG("read failed (tmp)"); | |
557 | goto fail; | |
558 | } | |
559 | *flags |= be32_to_cpu(tmp); | |
560 | } | |
561 | if (read_sync(csock, &buf, 124) != 124) { | |
562 | LOG("read failed (buf)"); | |
563 | goto fail; | |
564 | } | |
565 | rc = 0; | |
566 | ||
567 | fail: | |
568 | socket_set_nonblock(csock); | |
569 | return rc; | |
570 | } | |
571 | ||
572 | #ifdef __linux__ | |
573 | int nbd_init(int fd, int csock, uint32_t flags, off_t size, size_t blocksize) | |
574 | { | |
575 | TRACE("Setting NBD socket"); | |
576 | ||
577 | if (ioctl(fd, NBD_SET_SOCK, csock) < 0) { | |
578 | int serrno = errno; | |
579 | LOG("Failed to set NBD socket"); | |
580 | return -serrno; | |
581 | } | |
582 | ||
583 | TRACE("Setting block size to %lu", (unsigned long)blocksize); | |
584 | ||
585 | if (ioctl(fd, NBD_SET_BLKSIZE, blocksize) < 0) { | |
586 | int serrno = errno; | |
587 | LOG("Failed setting NBD block size"); | |
588 | return -serrno; | |
589 | } | |
590 | ||
591 | TRACE("Setting size to %zd block(s)", (size_t)(size / blocksize)); | |
592 | ||
593 | if (ioctl(fd, NBD_SET_SIZE_BLOCKS, size / blocksize) < 0) { | |
594 | int serrno = errno; | |
595 | LOG("Failed setting size (in blocks)"); | |
596 | return -serrno; | |
597 | } | |
598 | ||
599 | if (ioctl(fd, NBD_SET_FLAGS, flags) < 0) { | |
600 | if (errno == ENOTTY) { | |
601 | int read_only = (flags & NBD_FLAG_READ_ONLY) != 0; | |
602 | TRACE("Setting readonly attribute"); | |
603 | ||
604 | if (ioctl(fd, BLKROSET, (unsigned long) &read_only) < 0) { | |
605 | int serrno = errno; | |
606 | LOG("Failed setting read-only attribute"); | |
607 | return -serrno; | |
608 | } | |
609 | } else { | |
610 | int serrno = errno; | |
611 | LOG("Failed setting flags"); | |
612 | return -serrno; | |
613 | } | |
614 | } | |
615 | ||
616 | TRACE("Negotiation ended"); | |
617 | ||
618 | return 0; | |
619 | } | |
620 | ||
621 | int nbd_disconnect(int fd) | |
622 | { | |
623 | ioctl(fd, NBD_CLEAR_QUE); | |
624 | ioctl(fd, NBD_DISCONNECT); | |
625 | ioctl(fd, NBD_CLEAR_SOCK); | |
626 | return 0; | |
627 | } | |
628 | ||
629 | int nbd_client(int fd) | |
630 | { | |
631 | int ret; | |
632 | int serrno; | |
633 | ||
634 | TRACE("Doing NBD loop"); | |
635 | ||
636 | ret = ioctl(fd, NBD_DO_IT); | |
637 | if (ret < 0 && errno == EPIPE) { | |
638 | /* NBD_DO_IT normally returns EPIPE when someone has disconnected | |
639 | * the socket via NBD_DISCONNECT. We do not want to return 1 in | |
640 | * that case. | |
641 | */ | |
642 | ret = 0; | |
643 | } | |
644 | serrno = errno; | |
645 | ||
646 | TRACE("NBD loop returned %d: %s", ret, strerror(serrno)); | |
647 | ||
648 | TRACE("Clearing NBD queue"); | |
649 | ioctl(fd, NBD_CLEAR_QUE); | |
650 | ||
651 | TRACE("Clearing NBD socket"); | |
652 | ioctl(fd, NBD_CLEAR_SOCK); | |
653 | ||
654 | errno = serrno; | |
655 | return ret; | |
656 | } | |
657 | #else | |
658 | int nbd_init(int fd, int csock, uint32_t flags, off_t size, size_t blocksize) | |
659 | { | |
660 | return -ENOTSUP; | |
661 | } | |
662 | ||
663 | int nbd_disconnect(int fd) | |
664 | { | |
665 | return -ENOTSUP; | |
666 | } | |
667 | ||
668 | int nbd_client(int fd) | |
669 | { | |
670 | return -ENOTSUP; | |
671 | } | |
672 | #endif | |
673 | ||
674 | ssize_t nbd_send_request(int csock, struct nbd_request *request) | |
675 | { | |
676 | uint8_t buf[NBD_REQUEST_SIZE]; | |
677 | ssize_t ret; | |
678 | ||
679 | cpu_to_be32w((uint32_t*)buf, NBD_REQUEST_MAGIC); | |
680 | cpu_to_be32w((uint32_t*)(buf + 4), request->type); | |
681 | cpu_to_be64w((uint64_t*)(buf + 8), request->handle); | |
682 | cpu_to_be64w((uint64_t*)(buf + 16), request->from); | |
683 | cpu_to_be32w((uint32_t*)(buf + 24), request->len); | |
684 | ||
685 | TRACE("Sending request to client: " | |
686 | "{ .from = %" PRIu64", .len = %u, .handle = %" PRIu64", .type=%i}", | |
687 | request->from, request->len, request->handle, request->type); | |
688 | ||
689 | ret = write_sync(csock, buf, sizeof(buf)); | |
690 | if (ret < 0) { | |
691 | return ret; | |
692 | } | |
693 | ||
694 | if (ret != sizeof(buf)) { | |
695 | LOG("writing to socket failed"); | |
696 | return -EINVAL; | |
697 | } | |
698 | return 0; | |
699 | } | |
700 | ||
701 | static ssize_t nbd_receive_request(int csock, struct nbd_request *request) | |
702 | { | |
703 | uint8_t buf[NBD_REQUEST_SIZE]; | |
704 | uint32_t magic; | |
705 | ssize_t ret; | |
706 | ||
707 | ret = read_sync(csock, buf, sizeof(buf)); | |
708 | if (ret < 0) { | |
709 | return ret; | |
710 | } | |
711 | ||
712 | if (ret != sizeof(buf)) { | |
713 | LOG("read failed"); | |
714 | return -EINVAL; | |
715 | } | |
716 | ||
717 | /* Request | |
718 | [ 0 .. 3] magic (NBD_REQUEST_MAGIC) | |
719 | [ 4 .. 7] type (0 == READ, 1 == WRITE) | |
720 | [ 8 .. 15] handle | |
721 | [16 .. 23] from | |
722 | [24 .. 27] len | |
723 | */ | |
724 | ||
725 | magic = be32_to_cpup((uint32_t*)buf); | |
726 | request->type = be32_to_cpup((uint32_t*)(buf + 4)); | |
727 | request->handle = be64_to_cpup((uint64_t*)(buf + 8)); | |
728 | request->from = be64_to_cpup((uint64_t*)(buf + 16)); | |
729 | request->len = be32_to_cpup((uint32_t*)(buf + 24)); | |
730 | ||
731 | TRACE("Got request: " | |
732 | "{ magic = 0x%x, .type = %d, from = %" PRIu64" , len = %u }", | |
733 | magic, request->type, request->from, request->len); | |
734 | ||
735 | if (magic != NBD_REQUEST_MAGIC) { | |
736 | LOG("invalid magic (got 0x%x)", magic); | |
737 | return -EINVAL; | |
738 | } | |
739 | return 0; | |
740 | } | |
741 | ||
742 | ssize_t nbd_receive_reply(int csock, struct nbd_reply *reply) | |
743 | { | |
744 | uint8_t buf[NBD_REPLY_SIZE]; | |
745 | uint32_t magic; | |
746 | ssize_t ret; | |
747 | ||
748 | ret = read_sync(csock, buf, sizeof(buf)); | |
749 | if (ret < 0) { | |
750 | return ret; | |
751 | } | |
752 | ||
753 | if (ret != sizeof(buf)) { | |
754 | LOG("read failed"); | |
755 | return -EINVAL; | |
756 | } | |
757 | ||
758 | /* Reply | |
759 | [ 0 .. 3] magic (NBD_REPLY_MAGIC) | |
760 | [ 4 .. 7] error (0 == no error) | |
761 | [ 7 .. 15] handle | |
762 | */ | |
763 | ||
764 | magic = be32_to_cpup((uint32_t*)buf); | |
765 | reply->error = be32_to_cpup((uint32_t*)(buf + 4)); | |
766 | reply->handle = be64_to_cpup((uint64_t*)(buf + 8)); | |
767 | ||
768 | TRACE("Got reply: " | |
769 | "{ magic = 0x%x, .error = %d, handle = %" PRIu64" }", | |
770 | magic, reply->error, reply->handle); | |
771 | ||
772 | if (magic != NBD_REPLY_MAGIC) { | |
773 | LOG("invalid magic (got 0x%x)", magic); | |
774 | return -EINVAL; | |
775 | } | |
776 | return 0; | |
777 | } | |
778 | ||
779 | static ssize_t nbd_send_reply(int csock, struct nbd_reply *reply) | |
780 | { | |
781 | uint8_t buf[NBD_REPLY_SIZE]; | |
782 | ssize_t ret; | |
783 | ||
784 | /* Reply | |
785 | [ 0 .. 3] magic (NBD_REPLY_MAGIC) | |
786 | [ 4 .. 7] error (0 == no error) | |
787 | [ 7 .. 15] handle | |
788 | */ | |
789 | cpu_to_be32w((uint32_t*)buf, NBD_REPLY_MAGIC); | |
790 | cpu_to_be32w((uint32_t*)(buf + 4), reply->error); | |
791 | cpu_to_be64w((uint64_t*)(buf + 8), reply->handle); | |
792 | ||
793 | TRACE("Sending response to client"); | |
794 | ||
795 | ret = write_sync(csock, buf, sizeof(buf)); | |
796 | if (ret < 0) { | |
797 | return ret; | |
798 | } | |
799 | ||
800 | if (ret != sizeof(buf)) { | |
801 | LOG("writing to socket failed"); | |
802 | return -EINVAL; | |
803 | } | |
804 | return 0; | |
805 | } | |
806 | ||
807 | #define MAX_NBD_REQUESTS 16 | |
808 | ||
809 | void nbd_client_get(NBDClient *client) | |
810 | { | |
811 | client->refcount++; | |
812 | } | |
813 | ||
814 | void nbd_client_put(NBDClient *client) | |
815 | { | |
816 | if (--client->refcount == 0) { | |
817 | /* The last reference should be dropped by client->close, | |
818 | * which is called by nbd_client_close. | |
819 | */ | |
820 | assert(client->closing); | |
821 | ||
822 | qemu_set_fd_handler2(client->sock, NULL, NULL, NULL, NULL); | |
823 | close(client->sock); | |
824 | client->sock = -1; | |
825 | if (client->exp) { | |
826 | QTAILQ_REMOVE(&client->exp->clients, client, next); | |
827 | nbd_export_put(client->exp); | |
828 | } | |
829 | g_free(client); | |
830 | } | |
831 | } | |
832 | ||
833 | void nbd_client_close(NBDClient *client) | |
834 | { | |
835 | if (client->closing) { | |
836 | return; | |
837 | } | |
838 | ||
839 | client->closing = true; | |
840 | ||
841 | /* Force requests to finish. They will drop their own references, | |
842 | * then we'll close the socket and free the NBDClient. | |
843 | */ | |
844 | shutdown(client->sock, 2); | |
845 | ||
846 | /* Also tell the client, so that they release their reference. */ | |
847 | if (client->close) { | |
848 | client->close(client); | |
849 | } | |
850 | } | |
851 | ||
852 | static NBDRequest *nbd_request_get(NBDClient *client) | |
853 | { | |
854 | NBDRequest *req; | |
855 | NBDExport *exp = client->exp; | |
856 | ||
857 | assert(client->nb_requests <= MAX_NBD_REQUESTS - 1); | |
858 | client->nb_requests++; | |
859 | ||
860 | if (QSIMPLEQ_EMPTY(&exp->requests)) { | |
861 | req = g_malloc0(sizeof(NBDRequest)); | |
862 | req->data = qemu_blockalign(exp->bs, NBD_BUFFER_SIZE); | |
863 | } else { | |
864 | req = QSIMPLEQ_FIRST(&exp->requests); | |
865 | QSIMPLEQ_REMOVE_HEAD(&exp->requests, entry); | |
866 | } | |
867 | nbd_client_get(client); | |
868 | req->client = client; | |
869 | return req; | |
870 | } | |
871 | ||
872 | static void nbd_request_put(NBDRequest *req) | |
873 | { | |
874 | NBDClient *client = req->client; | |
875 | QSIMPLEQ_INSERT_HEAD(&client->exp->requests, req, entry); | |
876 | if (client->nb_requests-- == MAX_NBD_REQUESTS) { | |
877 | qemu_notify_event(); | |
878 | } | |
879 | nbd_client_put(client); | |
880 | } | |
881 | ||
882 | NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, | |
883 | off_t size, uint32_t nbdflags, | |
884 | void (*close)(NBDExport *)) | |
885 | { | |
886 | NBDExport *exp = g_malloc0(sizeof(NBDExport)); | |
887 | QSIMPLEQ_INIT(&exp->requests); | |
888 | exp->refcount = 1; | |
889 | QTAILQ_INIT(&exp->clients); | |
890 | exp->bs = bs; | |
891 | exp->dev_offset = dev_offset; | |
892 | exp->nbdflags = nbdflags; | |
893 | exp->size = size == -1 ? bdrv_getlength(bs) : size; | |
894 | exp->close = close; | |
895 | return exp; | |
896 | } | |
897 | ||
898 | NBDExport *nbd_export_find(const char *name) | |
899 | { | |
900 | NBDExport *exp; | |
901 | QTAILQ_FOREACH(exp, &exports, next) { | |
902 | if (strcmp(name, exp->name) == 0) { | |
903 | return exp; | |
904 | } | |
905 | } | |
906 | ||
907 | return NULL; | |
908 | } | |
909 | ||
910 | void nbd_export_set_name(NBDExport *exp, const char *name) | |
911 | { | |
912 | if (exp->name == name) { | |
913 | return; | |
914 | } | |
915 | ||
916 | nbd_export_get(exp); | |
917 | if (exp->name != NULL) { | |
918 | g_free(exp->name); | |
919 | exp->name = NULL; | |
920 | QTAILQ_REMOVE(&exports, exp, next); | |
921 | nbd_export_put(exp); | |
922 | } | |
923 | if (name != NULL) { | |
924 | nbd_export_get(exp); | |
925 | exp->name = g_strdup(name); | |
926 | QTAILQ_INSERT_TAIL(&exports, exp, next); | |
927 | } | |
928 | nbd_export_put(exp); | |
929 | } | |
930 | ||
931 | void nbd_export_close(NBDExport *exp) | |
932 | { | |
933 | NBDClient *client, *next; | |
934 | ||
935 | nbd_export_get(exp); | |
936 | QTAILQ_FOREACH_SAFE(client, &exp->clients, next, next) { | |
937 | nbd_client_close(client); | |
938 | } | |
939 | nbd_export_set_name(exp, NULL); | |
940 | nbd_export_put(exp); | |
941 | } | |
942 | ||
943 | void nbd_export_get(NBDExport *exp) | |
944 | { | |
945 | assert(exp->refcount > 0); | |
946 | exp->refcount++; | |
947 | } | |
948 | ||
949 | void nbd_export_put(NBDExport *exp) | |
950 | { | |
951 | assert(exp->refcount > 0); | |
952 | if (exp->refcount == 1) { | |
953 | nbd_export_close(exp); | |
954 | } | |
955 | ||
956 | if (--exp->refcount == 0) { | |
957 | assert(exp->name == NULL); | |
958 | ||
959 | if (exp->close) { | |
960 | exp->close(exp); | |
961 | } | |
962 | ||
963 | while (!QSIMPLEQ_EMPTY(&exp->requests)) { | |
964 | NBDRequest *first = QSIMPLEQ_FIRST(&exp->requests); | |
965 | QSIMPLEQ_REMOVE_HEAD(&exp->requests, entry); | |
966 | qemu_vfree(first->data); | |
967 | g_free(first); | |
968 | } | |
969 | ||
970 | g_free(exp); | |
971 | } | |
972 | } | |
973 | ||
974 | BlockDriverState *nbd_export_get_blockdev(NBDExport *exp) | |
975 | { | |
976 | return exp->bs; | |
977 | } | |
978 | ||
979 | void nbd_export_close_all(void) | |
980 | { | |
981 | NBDExport *exp, *next; | |
982 | ||
983 | QTAILQ_FOREACH_SAFE(exp, &exports, next, next) { | |
984 | nbd_export_close(exp); | |
985 | } | |
986 | } | |
987 | ||
988 | static int nbd_can_read(void *opaque); | |
989 | static void nbd_read(void *opaque); | |
990 | static void nbd_restart_write(void *opaque); | |
991 | ||
992 | static ssize_t nbd_co_send_reply(NBDRequest *req, struct nbd_reply *reply, | |
993 | int len) | |
994 | { | |
995 | NBDClient *client = req->client; | |
996 | int csock = client->sock; | |
997 | ssize_t rc, ret; | |
998 | ||
999 | qemu_co_mutex_lock(&client->send_lock); | |
1000 | qemu_set_fd_handler2(csock, nbd_can_read, nbd_read, | |
1001 | nbd_restart_write, client); | |
1002 | client->send_coroutine = qemu_coroutine_self(); | |
1003 | ||
1004 | if (!len) { | |
1005 | rc = nbd_send_reply(csock, reply); | |
1006 | } else { | |
1007 | socket_set_cork(csock, 1); | |
1008 | rc = nbd_send_reply(csock, reply); | |
1009 | if (rc >= 0) { | |
1010 | ret = qemu_co_send(csock, req->data, len); | |
1011 | if (ret != len) { | |
1012 | rc = -EIO; | |
1013 | } | |
1014 | } | |
1015 | socket_set_cork(csock, 0); | |
1016 | } | |
1017 | ||
1018 | client->send_coroutine = NULL; | |
1019 | qemu_set_fd_handler2(csock, nbd_can_read, nbd_read, NULL, client); | |
1020 | qemu_co_mutex_unlock(&client->send_lock); | |
1021 | return rc; | |
1022 | } | |
1023 | ||
1024 | static ssize_t nbd_co_receive_request(NBDRequest *req, struct nbd_request *request) | |
1025 | { | |
1026 | NBDClient *client = req->client; | |
1027 | int csock = client->sock; | |
1028 | ssize_t rc; | |
1029 | ||
1030 | client->recv_coroutine = qemu_coroutine_self(); | |
1031 | rc = nbd_receive_request(csock, request); | |
1032 | if (rc < 0) { | |
1033 | if (rc != -EAGAIN) { | |
1034 | rc = -EIO; | |
1035 | } | |
1036 | goto out; | |
1037 | } | |
1038 | ||
1039 | if (request->len > NBD_BUFFER_SIZE) { | |
1040 | LOG("len (%u) is larger than max len (%u)", | |
1041 | request->len, NBD_BUFFER_SIZE); | |
1042 | rc = -EINVAL; | |
1043 | goto out; | |
1044 | } | |
1045 | ||
1046 | if ((request->from + request->len) < request->from) { | |
1047 | LOG("integer overflow detected! " | |
1048 | "you're probably being attacked"); | |
1049 | rc = -EINVAL; | |
1050 | goto out; | |
1051 | } | |
1052 | ||
1053 | TRACE("Decoding type"); | |
1054 | ||
1055 | if ((request->type & NBD_CMD_MASK_COMMAND) == NBD_CMD_WRITE) { | |
1056 | TRACE("Reading %u byte(s)", request->len); | |
1057 | ||
1058 | if (qemu_co_recv(csock, req->data, request->len) != request->len) { | |
1059 | LOG("reading from socket failed"); | |
1060 | rc = -EIO; | |
1061 | goto out; | |
1062 | } | |
1063 | } | |
1064 | rc = 0; | |
1065 | ||
1066 | out: | |
1067 | client->recv_coroutine = NULL; | |
1068 | return rc; | |
1069 | } | |
1070 | ||
1071 | static void nbd_trip(void *opaque) | |
1072 | { | |
1073 | NBDClient *client = opaque; | |
1074 | NBDExport *exp = client->exp; | |
1075 | NBDRequest *req; | |
1076 | struct nbd_request request; | |
1077 | struct nbd_reply reply; | |
1078 | ssize_t ret; | |
1079 | ||
1080 | TRACE("Reading request."); | |
1081 | if (client->closing) { | |
1082 | return; | |
1083 | } | |
1084 | ||
1085 | req = nbd_request_get(client); | |
1086 | ret = nbd_co_receive_request(req, &request); | |
1087 | if (ret == -EAGAIN) { | |
1088 | goto done; | |
1089 | } | |
1090 | if (ret == -EIO) { | |
1091 | goto out; | |
1092 | } | |
1093 | ||
1094 | reply.handle = request.handle; | |
1095 | reply.error = 0; | |
1096 | ||
1097 | if (ret < 0) { | |
1098 | reply.error = -ret; | |
1099 | goto error_reply; | |
1100 | } | |
1101 | ||
1102 | if ((request.from + request.len) > exp->size) { | |
1103 | LOG("From: %" PRIu64 ", Len: %u, Size: %" PRIu64 | |
1104 | ", Offset: %" PRIu64 "\n", | |
1105 | request.from, request.len, | |
1106 | (uint64_t)exp->size, (uint64_t)exp->dev_offset); | |
1107 | LOG("requested operation past EOF--bad client?"); | |
1108 | goto invalid_request; | |
1109 | } | |
1110 | ||
1111 | switch (request.type & NBD_CMD_MASK_COMMAND) { | |
1112 | case NBD_CMD_READ: | |
1113 | TRACE("Request type is READ"); | |
1114 | ||
1115 | if (request.type & NBD_CMD_FLAG_FUA) { | |
1116 | ret = bdrv_co_flush(exp->bs); | |
1117 | if (ret < 0) { | |
1118 | LOG("flush failed"); | |
1119 | reply.error = -ret; | |
1120 | goto error_reply; | |
1121 | } | |
1122 | } | |
1123 | ||
1124 | ret = bdrv_read(exp->bs, (request.from + exp->dev_offset) / 512, | |
1125 | req->data, request.len / 512); | |
1126 | if (ret < 0) { | |
1127 | LOG("reading from file failed"); | |
1128 | reply.error = -ret; | |
1129 | goto error_reply; | |
1130 | } | |
1131 | ||
1132 | TRACE("Read %u byte(s)", request.len); | |
1133 | if (nbd_co_send_reply(req, &reply, request.len) < 0) | |
1134 | goto out; | |
1135 | break; | |
1136 | case NBD_CMD_WRITE: | |
1137 | TRACE("Request type is WRITE"); | |
1138 | ||
1139 | if (exp->nbdflags & NBD_FLAG_READ_ONLY) { | |
1140 | TRACE("Server is read-only, return error"); | |
1141 | reply.error = EROFS; | |
1142 | goto error_reply; | |
1143 | } | |
1144 | ||
1145 | TRACE("Writing to device"); | |
1146 | ||
1147 | ret = bdrv_write(exp->bs, (request.from + exp->dev_offset) / 512, | |
1148 | req->data, request.len / 512); | |
1149 | if (ret < 0) { | |
1150 | LOG("writing to file failed"); | |
1151 | reply.error = -ret; | |
1152 | goto error_reply; | |
1153 | } | |
1154 | ||
1155 | if (request.type & NBD_CMD_FLAG_FUA) { | |
1156 | ret = bdrv_co_flush(exp->bs); | |
1157 | if (ret < 0) { | |
1158 | LOG("flush failed"); | |
1159 | reply.error = -ret; | |
1160 | goto error_reply; | |
1161 | } | |
1162 | } | |
1163 | ||
1164 | if (nbd_co_send_reply(req, &reply, 0) < 0) { | |
1165 | goto out; | |
1166 | } | |
1167 | break; | |
1168 | case NBD_CMD_DISC: | |
1169 | TRACE("Request type is DISCONNECT"); | |
1170 | errno = 0; | |
1171 | goto out; | |
1172 | case NBD_CMD_FLUSH: | |
1173 | TRACE("Request type is FLUSH"); | |
1174 | ||
1175 | ret = bdrv_co_flush(exp->bs); | |
1176 | if (ret < 0) { | |
1177 | LOG("flush failed"); | |
1178 | reply.error = -ret; | |
1179 | } | |
1180 | if (nbd_co_send_reply(req, &reply, 0) < 0) { | |
1181 | goto out; | |
1182 | } | |
1183 | break; | |
1184 | case NBD_CMD_TRIM: | |
1185 | TRACE("Request type is TRIM"); | |
1186 | ret = bdrv_co_discard(exp->bs, (request.from + exp->dev_offset) / 512, | |
1187 | request.len / 512); | |
1188 | if (ret < 0) { | |
1189 | LOG("discard failed"); | |
1190 | reply.error = -ret; | |
1191 | } | |
1192 | if (nbd_co_send_reply(req, &reply, 0) < 0) { | |
1193 | goto out; | |
1194 | } | |
1195 | break; | |
1196 | default: | |
1197 | LOG("invalid request type (%u) received", request.type); | |
1198 | invalid_request: | |
1199 | reply.error = -EINVAL; | |
1200 | error_reply: | |
1201 | if (nbd_co_send_reply(req, &reply, 0) < 0) { | |
1202 | goto out; | |
1203 | } | |
1204 | break; | |
1205 | } | |
1206 | ||
1207 | TRACE("Request/Reply complete"); | |
1208 | ||
1209 | done: | |
1210 | nbd_request_put(req); | |
1211 | return; | |
1212 | ||
1213 | out: | |
1214 | nbd_request_put(req); | |
1215 | nbd_client_close(client); | |
1216 | } | |
1217 | ||
1218 | static int nbd_can_read(void *opaque) | |
1219 | { | |
1220 | NBDClient *client = opaque; | |
1221 | ||
1222 | return client->recv_coroutine || client->nb_requests < MAX_NBD_REQUESTS; | |
1223 | } | |
1224 | ||
1225 | static void nbd_read(void *opaque) | |
1226 | { | |
1227 | NBDClient *client = opaque; | |
1228 | ||
1229 | if (client->recv_coroutine) { | |
1230 | qemu_coroutine_enter(client->recv_coroutine, NULL); | |
1231 | } else { | |
1232 | qemu_coroutine_enter(qemu_coroutine_create(nbd_trip), client); | |
1233 | } | |
1234 | } | |
1235 | ||
1236 | static void nbd_restart_write(void *opaque) | |
1237 | { | |
1238 | NBDClient *client = opaque; | |
1239 | ||
1240 | qemu_coroutine_enter(client->send_coroutine, NULL); | |
1241 | } | |
1242 | ||
1243 | NBDClient *nbd_client_new(NBDExport *exp, int csock, | |
1244 | void (*close)(NBDClient *)) | |
1245 | { | |
1246 | NBDClient *client; | |
1247 | client = g_malloc0(sizeof(NBDClient)); | |
1248 | client->refcount = 1; | |
1249 | client->exp = exp; | |
1250 | client->sock = csock; | |
1251 | if (nbd_send_negotiate(client) < 0) { | |
1252 | g_free(client); | |
1253 | return NULL; | |
1254 | } | |
1255 | client->close = close; | |
1256 | qemu_co_mutex_init(&client->send_lock); | |
1257 | qemu_set_fd_handler2(csock, nbd_can_read, nbd_read, NULL, client); | |
1258 | ||
1259 | if (exp) { | |
1260 | QTAILQ_INSERT_TAIL(&exp->clients, client, next); | |
1261 | nbd_export_get(exp); | |
1262 | } | |
1263 | return client; | |
1264 | } |