]> git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blob - drivers/block/nbd.c
projects / mirror_ubuntu-artful-kernel.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
Merge tag 'imx-fixes-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/shawnguo...
[mirror_ubuntu-artful-kernel.git] / drivers / block / nbd.c
1 /*
2 * Network block device - make block devices work over TCP
3 *
4 * Note that you can not swap over this thing, yet. Seems to work but
5 * deadlocks sometimes - you can not swap over TCP in general.
6 *
7 * Copyright 1997-2000, 2008 Pavel Machek <pavel@ucw.cz>
8 * Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com>
9 *
10 * This file is released under GPLv2 or later.
11 *
12 * (part of code stolen from loop.c)
13 */
14
15 #include <linux/major.h>
16
17 #include <linux/blkdev.h>
18 #include <linux/module.h>
19 #include <linux/init.h>
20 #include <linux/sched.h>
21 #include <linux/sched/mm.h>
22 #include <linux/fs.h>
23 #include <linux/bio.h>
24 #include <linux/stat.h>
25 #include <linux/errno.h>
26 #include <linux/file.h>
27 #include <linux/ioctl.h>
28 #include <linux/mutex.h>
29 #include <linux/compiler.h>
30 #include <linux/err.h>
31 #include <linux/kernel.h>
32 #include <linux/slab.h>
33 #include <net/sock.h>
34 #include <linux/net.h>
35 #include <linux/kthread.h>
36 #include <linux/types.h>
37 #include <linux/debugfs.h>
38 #include <linux/blk-mq.h>
39
40 #include <linux/uaccess.h>
41 #include <asm/types.h>
42
43 #include <linux/nbd.h>
44 #include <linux/nbd-netlink.h>
45 #include <net/genetlink.h>
46
47 static DEFINE_IDR(nbd_index_idr);
48 static DEFINE_MUTEX(nbd_index_mutex);
49 static int nbd_total_devices = 0;
50
51 struct nbd_sock {
52 struct socket *sock;
53 struct mutex tx_lock;
54 struct request *pending;
55 int sent;
56 bool dead;
57 int fallback_index;
58 int cookie;
59 };
60
61 struct recv_thread_args {
62 struct work_struct work;
63 struct nbd_device *nbd;
64 int index;
65 };
66
67 struct link_dead_args {
68 struct work_struct work;
69 int index;
70 };
71
72 #define NBD_TIMEDOUT 0
73 #define NBD_DISCONNECT_REQUESTED 1
74 #define NBD_DISCONNECTED 2
75 #define NBD_HAS_PID_FILE 3
76 #define NBD_HAS_CONFIG_REF 4
77 #define NBD_BOUND 5
78 #define NBD_DESTROY_ON_DISCONNECT 6
79
80 struct nbd_config {
81 u32 flags;
82 unsigned long runtime_flags;
83 u64 dead_conn_timeout;
84
85 struct nbd_sock **socks;
86 int num_connections;
87 atomic_t live_connections;
88 wait_queue_head_t conn_wait;
89
90 atomic_t recv_threads;
91 wait_queue_head_t recv_wq;
92 loff_t blksize;
93 loff_t bytesize;
94 #if IS_ENABLED(CONFIG_DEBUG_FS)
95 struct dentry *dbg_dir;
96 #endif
97 };
98
99 struct nbd_device {
100 struct blk_mq_tag_set tag_set;
101
102 int index;
103 refcount_t config_refs;
104 refcount_t refs;
105 struct nbd_config *config;
106 struct mutex config_lock;
107 struct gendisk *disk;
108
109 struct list_head list;
110 struct task_struct *task_recv;
111 struct task_struct *task_setup;
112 };
113
114 struct nbd_cmd {
115 struct nbd_device *nbd;
116 int index;
117 int cookie;
118 struct completion send_complete;
119 blk_status_t status;
120 };
121
122 #if IS_ENABLED(CONFIG_DEBUG_FS)
123 static struct dentry *nbd_dbg_dir;
124 #endif
125
126 #define nbd_name(nbd) ((nbd)->disk->disk_name)
127
128 #define NBD_MAGIC 0x68797548
129
130 static unsigned int nbds_max = 16;
131 static int max_part;
132 static struct workqueue_struct *recv_workqueue;
133 static int part_shift;
134
135 static int nbd_dev_dbg_init(struct nbd_device *nbd);
136 static void nbd_dev_dbg_close(struct nbd_device *nbd);
137 static void nbd_config_put(struct nbd_device *nbd);
138 static void nbd_connect_reply(struct genl_info *info, int index);
139 static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info);
140 static void nbd_dead_link_work(struct work_struct *work);
141
142 static inline struct device *nbd_to_dev(struct nbd_device *nbd)
143 {
144 return disk_to_dev(nbd->disk);
145 }
146
147 static const char *nbdcmd_to_ascii(int cmd)
148 {
149 switch (cmd) {
150 case NBD_CMD_READ: return "read";
151 case NBD_CMD_WRITE: return "write";
152 case NBD_CMD_DISC: return "disconnect";
153 case NBD_CMD_FLUSH: return "flush";
154 case NBD_CMD_TRIM: return "trim/discard";
155 }
156 return "invalid";
157 }
158
159 static ssize_t pid_show(struct device *dev,
160 struct device_attribute *attr, char *buf)
161 {
162 struct gendisk *disk = dev_to_disk(dev);
163 struct nbd_device *nbd = (struct nbd_device *)disk->private_data;
164
165 return sprintf(buf, "%d\n", task_pid_nr(nbd->task_recv));
166 }
167
168 static struct device_attribute pid_attr = {
169 .attr = { .name = "pid", .mode = S_IRUGO},
170 .show = pid_show,
171 };
172
173 static void nbd_dev_remove(struct nbd_device *nbd)
174 {
175 struct gendisk *disk = nbd->disk;
176 if (disk) {
177 del_gendisk(disk);
178 blk_cleanup_queue(disk->queue);
179 blk_mq_free_tag_set(&nbd->tag_set);
180 disk->private_data = NULL;
181 put_disk(disk);
182 }
183 kfree(nbd);
184 }
185
186 static void nbd_put(struct nbd_device *nbd)
187 {
188 if (refcount_dec_and_mutex_lock(&nbd->refs,
189 &nbd_index_mutex)) {
190 idr_remove(&nbd_index_idr, nbd->index);
191 mutex_unlock(&nbd_index_mutex);
192 nbd_dev_remove(nbd);
193 }
194 }
195
196 static int nbd_disconnected(struct nbd_config *config)
197 {
198 return test_bit(NBD_DISCONNECTED, &config->runtime_flags) ||
199 test_bit(NBD_DISCONNECT_REQUESTED, &config->runtime_flags);
200 }
201
202 static void nbd_mark_nsock_dead(struct nbd_device *nbd, struct nbd_sock *nsock,
203 int notify)
204 {
205 if (!nsock->dead && notify && !nbd_disconnected(nbd->config)) {
206 struct link_dead_args *args;
207 args = kmalloc(sizeof(struct link_dead_args), GFP_NOIO);
208 if (args) {
209 INIT_WORK(&args->work, nbd_dead_link_work);
210 args->index = nbd->index;
211 queue_work(system_wq, &args->work);
212 }
213 }
214 if (!nsock->dead) {
215 kernel_sock_shutdown(nsock->sock, SHUT_RDWR);
216 atomic_dec(&nbd->config->live_connections);
217 }
218 nsock->dead = true;
219 nsock->pending = NULL;
220 nsock->sent = 0;
221 }
222
223 static void nbd_size_clear(struct nbd_device *nbd)
224 {
225 if (nbd->config->bytesize) {
226 set_capacity(nbd->disk, 0);
227 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
228 }
229 }
230
231 static void nbd_size_update(struct nbd_device *nbd)
232 {
233 struct nbd_config *config = nbd->config;
234 blk_queue_logical_block_size(nbd->disk->queue, config->blksize);
235 blk_queue_physical_block_size(nbd->disk->queue, config->blksize);
236 set_capacity(nbd->disk, config->bytesize >> 9);
237 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
238 }
239
240 static void nbd_size_set(struct nbd_device *nbd, loff_t blocksize,
241 loff_t nr_blocks)
242 {
243 struct nbd_config *config = nbd->config;
244 config->blksize = blocksize;
245 config->bytesize = blocksize * nr_blocks;
246 nbd_size_update(nbd);
247 }
248
249 static void nbd_complete_rq(struct request *req)
250 {
251 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
252
253 dev_dbg(nbd_to_dev(cmd->nbd), "request %p: %s\n", cmd,
254 cmd->status ? "failed" : "done");
255
256 blk_mq_end_request(req, cmd->status);
257 }
258
259 /*
260 * Forcibly shutdown the socket causing all listeners to error
261 */
262 static void sock_shutdown(struct nbd_device *nbd)
263 {
264 struct nbd_config *config = nbd->config;
265 int i;
266
267 if (config->num_connections == 0)
268 return;
269 if (test_and_set_bit(NBD_DISCONNECTED, &config->runtime_flags))
270 return;
271
272 for (i = 0; i < config->num_connections; i++) {
273 struct nbd_sock *nsock = config->socks[i];
274 mutex_lock(&nsock->tx_lock);
275 nbd_mark_nsock_dead(nbd, nsock, 0);
276 mutex_unlock(&nsock->tx_lock);
277 }
278 dev_warn(disk_to_dev(nbd->disk), "shutting down sockets\n");
279 }
280
281 static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
282 bool reserved)
283 {
284 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
285 struct nbd_device *nbd = cmd->nbd;
286 struct nbd_config *config;
287
288 if (!refcount_inc_not_zero(&nbd->config_refs)) {
289 cmd->status = BLK_STS_TIMEOUT;
290 return BLK_EH_HANDLED;
291 }
292
293 /* If we are waiting on our dead timer then we could get timeout
294 * callbacks for our request. For this we just want to reset the timer
295 * and let the queue side take care of everything.
296 */
297 if (!completion_done(&cmd->send_complete)) {
298 nbd_config_put(nbd);
299 return BLK_EH_RESET_TIMER;
300 }
301 config = nbd->config;
302
303 if (config->num_connections > 1) {
304 dev_err_ratelimited(nbd_to_dev(nbd),
305 "Connection timed out, retrying\n");
306 /*
307 * Hooray we have more connections, requeue this IO, the submit
308 * path will put it on a real connection.
309 */
310 if (config->socks && config->num_connections > 1) {
311 if (cmd->index < config->num_connections) {
312 struct nbd_sock *nsock =
313 config->socks[cmd->index];
314 mutex_lock(&nsock->tx_lock);
315 /* We can have multiple outstanding requests, so
316 * we don't want to mark the nsock dead if we've
317 * already reconnected with a new socket, so
318 * only mark it dead if its the same socket we
319 * were sent out on.
320 */
321 if (cmd->cookie == nsock->cookie)
322 nbd_mark_nsock_dead(nbd, nsock, 1);
323 mutex_unlock(&nsock->tx_lock);
324 }
325 blk_mq_requeue_request(req, true);
326 nbd_config_put(nbd);
327 return BLK_EH_NOT_HANDLED;
328 }
329 } else {
330 dev_err_ratelimited(nbd_to_dev(nbd),
331 "Connection timed out\n");
332 }
333 set_bit(NBD_TIMEDOUT, &config->runtime_flags);
334 cmd->status = BLK_STS_IOERR;
335 sock_shutdown(nbd);
336 nbd_config_put(nbd);
337
338 return BLK_EH_HANDLED;
339 }
340
341 /*
342 * Send or receive packet.
343 */
344 static int sock_xmit(struct nbd_device *nbd, int index, int send,
345 struct iov_iter *iter, int msg_flags, int *sent)
346 {
347 struct nbd_config *config = nbd->config;
348 struct socket *sock = config->socks[index]->sock;
349 int result;
350 struct msghdr msg;
351 unsigned int noreclaim_flag;
352
353 if (unlikely(!sock)) {
354 dev_err_ratelimited(disk_to_dev(nbd->disk),
355 "Attempted %s on closed socket in sock_xmit\n",
356 (send ? "send" : "recv"));
357 return -EINVAL;
358 }
359
360 msg.msg_iter = *iter;
361
362 noreclaim_flag = memalloc_noreclaim_save();
363 do {
364 sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC;
365 msg.msg_name = NULL;
366 msg.msg_namelen = 0;
367 msg.msg_control = NULL;
368 msg.msg_controllen = 0;
369 msg.msg_flags = msg_flags | MSG_NOSIGNAL;
370
371 if (send)
372 result = sock_sendmsg(sock, &msg);
373 else
374 result = sock_recvmsg(sock, &msg, msg.msg_flags);
375
376 if (result <= 0) {
377 if (result == 0)
378 result = -EPIPE; /* short read */
379 break;
380 }
381 if (sent)
382 *sent += result;
383 } while (msg_data_left(&msg));
384
385 memalloc_noreclaim_restore(noreclaim_flag);
386
387 return result;
388 }
389
390 /* always call with the tx_lock held */
391 static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
392 {
393 struct request *req = blk_mq_rq_from_pdu(cmd);
394 struct nbd_config *config = nbd->config;
395 struct nbd_sock *nsock = config->socks[index];
396 int result;
397 struct nbd_request request = {.magic = htonl(NBD_REQUEST_MAGIC)};
398 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
399 struct iov_iter from;
400 unsigned long size = blk_rq_bytes(req);
401 struct bio *bio;
402 u32 type;
403 u32 nbd_cmd_flags = 0;
404 u32 tag = blk_mq_unique_tag(req);
405 int sent = nsock->sent, skip = 0;
406
407 iov_iter_kvec(&from, WRITE | ITER_KVEC, &iov, 1, sizeof(request));
408
409 switch (req_op(req)) {
410 case REQ_OP_DISCARD:
411 type = NBD_CMD_TRIM;
412 break;
413 case REQ_OP_FLUSH:
414 type = NBD_CMD_FLUSH;
415 break;
416 case REQ_OP_WRITE:
417 type = NBD_CMD_WRITE;
418 break;
419 case REQ_OP_READ:
420 type = NBD_CMD_READ;
421 break;
422 default:
423 return -EIO;
424 }
425
426 if (rq_data_dir(req) == WRITE &&
427 (config->flags & NBD_FLAG_READ_ONLY)) {
428 dev_err_ratelimited(disk_to_dev(nbd->disk),
429 "Write on read-only\n");
430 return -EIO;
431 }
432
433 if (req->cmd_flags & REQ_FUA)
434 nbd_cmd_flags |= NBD_CMD_FLAG_FUA;
435
436 /* We did a partial send previously, and we at least sent the whole
437 * request struct, so just go and send the rest of the pages in the
438 * request.
439 */
440 if (sent) {
441 if (sent >= sizeof(request)) {
442 skip = sent - sizeof(request);
443 goto send_pages;
444 }
445 iov_iter_advance(&from, sent);
446 }
447 cmd->index = index;
448 cmd->cookie = nsock->cookie;
449 request.type = htonl(type | nbd_cmd_flags);
450 if (type != NBD_CMD_FLUSH) {
451 request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
452 request.len = htonl(size);
453 }
454 memcpy(request.handle, &tag, sizeof(tag));
455
456 dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n",
457 cmd, nbdcmd_to_ascii(type),
458 (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req));
459 result = sock_xmit(nbd, index, 1, &from,
460 (type == NBD_CMD_WRITE) ? MSG_MORE : 0, &sent);
461 if (result <= 0) {
462 if (result == -ERESTARTSYS) {
463 /* If we havne't sent anything we can just return BUSY,
464 * however if we have sent something we need to make
465 * sure we only allow this req to be sent until we are
466 * completely done.
467 */
468 if (sent) {
469 nsock->pending = req;
470 nsock->sent = sent;
471 }
472 return BLK_STS_RESOURCE;
473 }
474 dev_err_ratelimited(disk_to_dev(nbd->disk),
475 "Send control failed (result %d)\n", result);
476 return -EAGAIN;
477 }
478 send_pages:
479 if (type != NBD_CMD_WRITE)
480 goto out;
481
482 bio = req->bio;
483 while (bio) {
484 struct bio *next = bio->bi_next;
485 struct bvec_iter iter;
486 struct bio_vec bvec;
487
488 bio_for_each_segment(bvec, bio, iter) {
489 bool is_last = !next && bio_iter_last(bvec, iter);
490 int flags = is_last ? 0 : MSG_MORE;
491
492 dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n",
493 cmd, bvec.bv_len);
494 iov_iter_bvec(&from, ITER_BVEC | WRITE,
495 &bvec, 1, bvec.bv_len);
496 if (skip) {
497 if (skip >= iov_iter_count(&from)) {
498 skip -= iov_iter_count(&from);
499 continue;
500 }
501 iov_iter_advance(&from, skip);
502 skip = 0;
503 }
504 result = sock_xmit(nbd, index, 1, &from, flags, &sent);
505 if (result <= 0) {
506 if (result == -ERESTARTSYS) {
507 /* We've already sent the header, we
508 * have no choice but to set pending and
509 * return BUSY.
510 */
511 nsock->pending = req;
512 nsock->sent = sent;
513 return BLK_STS_RESOURCE;
514 }
515 dev_err(disk_to_dev(nbd->disk),
516 "Send data failed (result %d)\n",
517 result);
518 return -EAGAIN;
519 }
520 /*
521 * The completion might already have come in,
522 * so break for the last one instead of letting
523 * the iterator do it. This prevents use-after-free
524 * of the bio.
525 */
526 if (is_last)
527 break;
528 }
529 bio = next;
530 }
531 out:
532 nsock->pending = NULL;
533 nsock->sent = 0;
534 return 0;
535 }
536
537 /* NULL returned = something went wrong, inform userspace */
538 static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
539 {
540 struct nbd_config *config = nbd->config;
541 int result;
542 struct nbd_reply reply;
543 struct nbd_cmd *cmd;
544 struct request *req = NULL;
545 u16 hwq;
546 u32 tag;
547 struct kvec iov = {.iov_base = &reply, .iov_len = sizeof(reply)};
548 struct iov_iter to;
549
550 reply.magic = 0;
551 iov_iter_kvec(&to, READ | ITER_KVEC, &iov, 1, sizeof(reply));
552 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
553 if (result <= 0) {
554 if (!nbd_disconnected(config))
555 dev_err(disk_to_dev(nbd->disk),
556 "Receive control failed (result %d)\n", result);
557 return ERR_PTR(result);
558 }
559
560 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) {
561 dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n",
562 (unsigned long)ntohl(reply.magic));
563 return ERR_PTR(-EPROTO);
564 }
565
566 memcpy(&tag, reply.handle, sizeof(u32));
567
568 hwq = blk_mq_unique_tag_to_hwq(tag);
569 if (hwq < nbd->tag_set.nr_hw_queues)
570 req = blk_mq_tag_to_rq(nbd->tag_set.tags[hwq],
571 blk_mq_unique_tag_to_tag(tag));
572 if (!req || !blk_mq_request_started(req)) {
573 dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%d) %p\n",
574 tag, req);
575 return ERR_PTR(-ENOENT);
576 }
577 cmd = blk_mq_rq_to_pdu(req);
578 if (ntohl(reply.error)) {
579 dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n",
580 ntohl(reply.error));
581 cmd->status = BLK_STS_IOERR;
582 return cmd;
583 }
584
585 dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", cmd);
586 if (rq_data_dir(req) != WRITE) {
587 struct req_iterator iter;
588 struct bio_vec bvec;
589
590 rq_for_each_segment(bvec, req, iter) {
591 iov_iter_bvec(&to, ITER_BVEC | READ,
592 &bvec, 1, bvec.bv_len);
593 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
594 if (result <= 0) {
595 dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
596 result);
597 /*
598 * If we've disconnected or we only have 1
599 * connection then we need to make sure we
600 * complete this request, otherwise error out
601 * and let the timeout stuff handle resubmitting
602 * this request onto another connection.
603 */
604 if (nbd_disconnected(config) ||
605 config->num_connections <= 1) {
606 cmd->status = BLK_STS_IOERR;
607 return cmd;
608 }
609 return ERR_PTR(-EIO);
610 }
611 dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n",
612 cmd, bvec.bv_len);
613 }
614 } else {
615 /* See the comment in nbd_queue_rq. */
616 wait_for_completion(&cmd->send_complete);
617 }
618 return cmd;
619 }
620
621 static void recv_work(struct work_struct *work)
622 {
623 struct recv_thread_args *args = container_of(work,
624 struct recv_thread_args,
625 work);
626 struct nbd_device *nbd = args->nbd;
627 struct nbd_config *config = nbd->config;
628 struct nbd_cmd *cmd;
629
630 while (1) {
631 cmd = nbd_read_stat(nbd, args->index);
632 if (IS_ERR(cmd)) {
633 struct nbd_sock *nsock = config->socks[args->index];
634
635 mutex_lock(&nsock->tx_lock);
636 nbd_mark_nsock_dead(nbd, nsock, 1);
637 mutex_unlock(&nsock->tx_lock);
638 break;
639 }
640
641 blk_mq_complete_request(blk_mq_rq_from_pdu(cmd));
642 }
643 atomic_dec(&config->recv_threads);
644 wake_up(&config->recv_wq);
645 nbd_config_put(nbd);
646 kfree(args);
647 }
648
649 static void nbd_clear_req(struct request *req, void *data, bool reserved)
650 {
651 struct nbd_cmd *cmd;
652
653 if (!blk_mq_request_started(req))
654 return;
655 cmd = blk_mq_rq_to_pdu(req);
656 cmd->status = BLK_STS_IOERR;
657 blk_mq_complete_request(req);
658 }
659
660 static void nbd_clear_que(struct nbd_device *nbd)
661 {
662 blk_mq_quiesce_queue(nbd->disk->queue);
663 blk_mq_tagset_busy_iter(&nbd->tag_set, nbd_clear_req, NULL);
664 blk_mq_unquiesce_queue(nbd->disk->queue);
665 dev_dbg(disk_to_dev(nbd->disk), "queue cleared\n");
666 }
667
668 static int find_fallback(struct nbd_device *nbd, int index)
669 {
670 struct nbd_config *config = nbd->config;
671 int new_index = -1;
672 struct nbd_sock *nsock = config->socks[index];
673 int fallback = nsock->fallback_index;
674
675 if (test_bit(NBD_DISCONNECTED, &config->runtime_flags))
676 return new_index;
677
678 if (config->num_connections <= 1) {
679 dev_err_ratelimited(disk_to_dev(nbd->disk),
680 "Attempted send on invalid socket\n");
681 return new_index;
682 }
683
684 if (fallback >= 0 && fallback < config->num_connections &&
685 !config->socks[fallback]->dead)
686 return fallback;
687
688 if (nsock->fallback_index < 0 ||
689 nsock->fallback_index >= config->num_connections ||
690 config->socks[nsock->fallback_index]->dead) {
691 int i;
692 for (i = 0; i < config->num_connections; i++) {
693 if (i == index)
694 continue;
695 if (!config->socks[i]->dead) {
696 new_index = i;
697 break;
698 }
699 }
700 nsock->fallback_index = new_index;
701 if (new_index < 0) {
702 dev_err_ratelimited(disk_to_dev(nbd->disk),
703 "Dead connection, failed to find a fallback\n");
704 return new_index;
705 }
706 }
707 new_index = nsock->fallback_index;
708 return new_index;
709 }
710
711 static int wait_for_reconnect(struct nbd_device *nbd)
712 {
713 struct nbd_config *config = nbd->config;
714 if (!config->dead_conn_timeout)
715 return 0;
716 if (test_bit(NBD_DISCONNECTED, &config->runtime_flags))
717 return 0;
718 wait_event_interruptible_timeout(config->conn_wait,
719 atomic_read(&config->live_connections),
720 config->dead_conn_timeout);
721 return atomic_read(&config->live_connections);
722 }
723
724 static int nbd_handle_cmd(struct nbd_cmd *cmd, int index)
725 {
726 struct request *req = blk_mq_rq_from_pdu(cmd);
727 struct nbd_device *nbd = cmd->nbd;
728 struct nbd_config *config;
729 struct nbd_sock *nsock;
730 int ret;
731
732 if (!refcount_inc_not_zero(&nbd->config_refs)) {
733 dev_err_ratelimited(disk_to_dev(nbd->disk),
734 "Socks array is empty\n");
735 return -EINVAL;
736 }
737 config = nbd->config;
738
739 if (index >= config->num_connections) {
740 dev_err_ratelimited(disk_to_dev(nbd->disk),
741 "Attempted send on invalid socket\n");
742 nbd_config_put(nbd);
743 return -EINVAL;
744 }
745 cmd->status = BLK_STS_OK;
746 again:
747 nsock = config->socks[index];
748 mutex_lock(&nsock->tx_lock);
749 if (nsock->dead) {
750 int old_index = index;
751 index = find_fallback(nbd, index);
752 mutex_unlock(&nsock->tx_lock);
753 if (index < 0) {
754 if (wait_for_reconnect(nbd)) {
755 index = old_index;
756 goto again;
757 }
758 /* All the sockets should already be down at this point,
759 * we just want to make sure that DISCONNECTED is set so
760 * any requests that come in that were queue'ed waiting
761 * for the reconnect timer don't trigger the timer again
762 * and instead just error out.
763 */
764 sock_shutdown(nbd);
765 nbd_config_put(nbd);
766 return -EIO;
767 }
768 goto again;
769 }
770
771 /* Handle the case that we have a pending request that was partially
772 * transmitted that _has_ to be serviced first. We need to call requeue
773 * here so that it gets put _after_ the request that is already on the
774 * dispatch list.
775 */
776 if (unlikely(nsock->pending && nsock->pending != req)) {
777 blk_mq_requeue_request(req, true);
778 ret = 0;
779 goto out;
780 }
781 /*
782 * Some failures are related to the link going down, so anything that
783 * returns EAGAIN can be retried on a different socket.
784 */
785 ret = nbd_send_cmd(nbd, cmd, index);
786 if (ret == -EAGAIN) {
787 dev_err_ratelimited(disk_to_dev(nbd->disk),
788 "Request send failed trying another connection\n");
789 nbd_mark_nsock_dead(nbd, nsock, 1);
790 mutex_unlock(&nsock->tx_lock);
791 goto again;
792 }
793 out:
794 mutex_unlock(&nsock->tx_lock);
795 nbd_config_put(nbd);
796 return ret;
797 }
798
799 static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
800 const struct blk_mq_queue_data *bd)
801 {
802 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
803 int ret;
804
805 /*
806 * Since we look at the bio's to send the request over the network we
807 * need to make sure the completion work doesn't mark this request done
808 * before we are done doing our send. This keeps us from dereferencing
809 * freed data if we have particularly fast completions (ie we get the
810 * completion before we exit sock_xmit on the last bvec) or in the case
811 * that the server is misbehaving (or there was an error) before we're
812 * done sending everything over the wire.
813 */
814 init_completion(&cmd->send_complete);
815 blk_mq_start_request(bd->rq);
816
817 /* We can be called directly from the user space process, which means we
818 * could possibly have signals pending so our sendmsg will fail. In
819 * this case we need to return that we are busy, otherwise error out as
820 * appropriate.
821 */
822 ret = nbd_handle_cmd(cmd, hctx->queue_num);
823 complete(&cmd->send_complete);
824
825 return ret < 0 ? BLK_STS_IOERR : BLK_STS_OK;
826 }
827
828 static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
829 bool netlink)
830 {
831 struct nbd_config *config = nbd->config;
832 struct socket *sock;
833 struct nbd_sock **socks;
834 struct nbd_sock *nsock;
835 int err;
836
837 sock = sockfd_lookup(arg, &err);
838 if (!sock)
839 return err;
840
841 if (!netlink && !nbd->task_setup &&
842 !test_bit(NBD_BOUND, &config->runtime_flags))
843 nbd->task_setup = current;
844
845 if (!netlink &&
846 (nbd->task_setup != current ||
847 test_bit(NBD_BOUND, &config->runtime_flags))) {
848 dev_err(disk_to_dev(nbd->disk),
849 "Device being setup by another task");
850 sockfd_put(sock);
851 return -EBUSY;
852 }
853
854 socks = krealloc(config->socks, (config->num_connections + 1) *
855 sizeof(struct nbd_sock *), GFP_KERNEL);
856 if (!socks) {
857 sockfd_put(sock);
858 return -ENOMEM;
859 }
860 nsock = kzalloc(sizeof(struct nbd_sock), GFP_KERNEL);
861 if (!nsock) {
862 sockfd_put(sock);
863 return -ENOMEM;
864 }
865
866 config->socks = socks;
867
868 nsock->fallback_index = -1;
869 nsock->dead = false;
870 mutex_init(&nsock->tx_lock);
871 nsock->sock = sock;
872 nsock->pending = NULL;
873 nsock->sent = 0;
874 nsock->cookie = 0;
875 socks[config->num_connections++] = nsock;
876 atomic_inc(&config->live_connections);
877
878 return 0;
879 }
880
881 static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg)
882 {
883 struct nbd_config *config = nbd->config;
884 struct socket *sock, *old;
885 struct recv_thread_args *args;
886 int i;
887 int err;
888
889 sock = sockfd_lookup(arg, &err);
890 if (!sock)
891 return err;
892
893 args = kzalloc(sizeof(*args), GFP_KERNEL);
894 if (!args) {
895 sockfd_put(sock);
896 return -ENOMEM;
897 }
898
899 for (i = 0; i < config->num_connections; i++) {
900 struct nbd_sock *nsock = config->socks[i];
901
902 if (!nsock->dead)
903 continue;
904
905 mutex_lock(&nsock->tx_lock);
906 if (!nsock->dead) {
907 mutex_unlock(&nsock->tx_lock);
908 continue;
909 }
910 sk_set_memalloc(sock->sk);
911 if (nbd->tag_set.timeout)
912 sock->sk->sk_sndtimeo = nbd->tag_set.timeout;
913 atomic_inc(&config->recv_threads);
914 refcount_inc(&nbd->config_refs);
915 old = nsock->sock;
916 nsock->fallback_index = -1;
917 nsock->sock = sock;
918 nsock->dead = false;
919 INIT_WORK(&args->work, recv_work);
920 args->index = i;
921 args->nbd = nbd;
922 nsock->cookie++;
923 mutex_unlock(&nsock->tx_lock);
924 sockfd_put(old);
925
926 clear_bit(NBD_DISCONNECTED, &config->runtime_flags);
927
928 /* We take the tx_mutex in an error path in the recv_work, so we
929 * need to queue_work outside of the tx_mutex.
930 */
931 queue_work(recv_workqueue, &args->work);
932
933 atomic_inc(&config->live_connections);
934 wake_up(&config->conn_wait);
935 return 0;
936 }
937 sockfd_put(sock);
938 kfree(args);
939 return -ENOSPC;
940 }
941
942 static void nbd_bdev_reset(struct block_device *bdev)
943 {
944 if (bdev->bd_openers > 1)
945 return;
946 bd_set_size(bdev, 0);
947 if (max_part > 0) {
948 blkdev_reread_part(bdev);
949 bdev->bd_invalidated = 1;
950 }
951 }
952
953 static void nbd_parse_flags(struct nbd_device *nbd)
954 {
955 struct nbd_config *config = nbd->config;
956 if (config->flags & NBD_FLAG_READ_ONLY)
957 set_disk_ro(nbd->disk, true);
958 else
959 set_disk_ro(nbd->disk, false);
960 if (config->flags & NBD_FLAG_SEND_TRIM)
961 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
962 if (config->flags & NBD_FLAG_SEND_FLUSH) {
963 if (config->flags & NBD_FLAG_SEND_FUA)
964 blk_queue_write_cache(nbd->disk->queue, true, true);
965 else
966 blk_queue_write_cache(nbd->disk->queue, true, false);
967 }
968 else
969 blk_queue_write_cache(nbd->disk->queue, false, false);
970 }
971
972 static void send_disconnects(struct nbd_device *nbd)
973 {
974 struct nbd_config *config = nbd->config;
975 struct nbd_request request = {
976 .magic = htonl(NBD_REQUEST_MAGIC),
977 .type = htonl(NBD_CMD_DISC),
978 };
979 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
980 struct iov_iter from;
981 int i, ret;
982
983 for (i = 0; i < config->num_connections; i++) {
984 struct nbd_sock *nsock = config->socks[i];
985
986 iov_iter_kvec(&from, WRITE | ITER_KVEC, &iov, 1, sizeof(request));
987 mutex_lock(&nsock->tx_lock);
988 ret = sock_xmit(nbd, i, 1, &from, 0, NULL);
989 if (ret <= 0)
990 dev_err(disk_to_dev(nbd->disk),
991 "Send disconnect failed %d\n", ret);
992 mutex_unlock(&nsock->tx_lock);
993 }
994 }
995
996 static int nbd_disconnect(struct nbd_device *nbd)
997 {
998 struct nbd_config *config = nbd->config;
999
1000 dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
1001 set_bit(NBD_DISCONNECT_REQUESTED, &config->runtime_flags);
1002 send_disconnects(nbd);
1003 return 0;
1004 }
1005
1006 static void nbd_clear_sock(struct nbd_device *nbd)
1007 {
1008 sock_shutdown(nbd);
1009 nbd_clear_que(nbd);
1010 nbd->task_setup = NULL;
1011 }
1012
1013 static void nbd_config_put(struct nbd_device *nbd)
1014 {
1015 if (refcount_dec_and_mutex_lock(&nbd->config_refs,
1016 &nbd->config_lock)) {
1017 struct nbd_config *config = nbd->config;
1018 nbd_dev_dbg_close(nbd);
1019 nbd_size_clear(nbd);
1020 if (test_and_clear_bit(NBD_HAS_PID_FILE,
1021 &config->runtime_flags))
1022 device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
1023 nbd->task_recv = NULL;
1024 nbd_clear_sock(nbd);
1025 if (config->num_connections) {
1026 int i;
1027 for (i = 0; i < config->num_connections; i++) {
1028 sockfd_put(config->socks[i]->sock);
1029 kfree(config->socks[i]);
1030 }
1031 kfree(config->socks);
1032 }
1033 kfree(nbd->config);
1034 nbd->config = NULL;
1035
1036 nbd->tag_set.timeout = 0;
1037 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
1038
1039 mutex_unlock(&nbd->config_lock);
1040 nbd_put(nbd);
1041 module_put(THIS_MODULE);
1042 }
1043 }
1044
1045 static int nbd_start_device(struct nbd_device *nbd)
1046 {
1047 struct nbd_config *config = nbd->config;
1048 int num_connections = config->num_connections;
1049 int error = 0, i;
1050
1051 if (nbd->task_recv)
1052 return -EBUSY;
1053 if (!config->socks)
1054 return -EINVAL;
1055 if (num_connections > 1 &&
1056 !(config->flags & NBD_FLAG_CAN_MULTI_CONN)) {
1057 dev_err(disk_to_dev(nbd->disk), "server does not support multiple connections per device.\n");
1058 return -EINVAL;
1059 }
1060
1061 blk_mq_update_nr_hw_queues(&nbd->tag_set, config->num_connections);
1062 nbd->task_recv = current;
1063
1064 nbd_parse_flags(nbd);
1065
1066 error = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
1067 if (error) {
1068 dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n");
1069 return error;
1070 }
1071 set_bit(NBD_HAS_PID_FILE, &config->runtime_flags);
1072
1073 nbd_dev_dbg_init(nbd);
1074 for (i = 0; i < num_connections; i++) {
1075 struct recv_thread_args *args;
1076
1077 args = kzalloc(sizeof(*args), GFP_KERNEL);
1078 if (!args) {
1079 sock_shutdown(nbd);
1080 return -ENOMEM;
1081 }
1082 sk_set_memalloc(config->socks[i]->sock->sk);
1083 if (nbd->tag_set.timeout)
1084 config->socks[i]->sock->sk->sk_sndtimeo =
1085 nbd->tag_set.timeout;
1086 atomic_inc(&config->recv_threads);
1087 refcount_inc(&nbd->config_refs);
1088 INIT_WORK(&args->work, recv_work);
1089 args->nbd = nbd;
1090 args->index = i;
1091 queue_work(recv_workqueue, &args->work);
1092 }
1093 return error;
1094 }
1095
1096 static int nbd_start_device_ioctl(struct nbd_device *nbd, struct block_device *bdev)
1097 {
1098 struct nbd_config *config = nbd->config;
1099 int ret;
1100
1101 ret = nbd_start_device(nbd);
1102 if (ret)
1103 return ret;
1104
1105 bd_set_size(bdev, config->bytesize);
1106 if (max_part)
1107 bdev->bd_invalidated = 1;
1108 mutex_unlock(&nbd->config_lock);
1109 ret = wait_event_interruptible(config->recv_wq,
1110 atomic_read(&config->recv_threads) == 0);
1111 if (ret)
1112 sock_shutdown(nbd);
1113 mutex_lock(&nbd->config_lock);
1114 bd_set_size(bdev, 0);
1115 /* user requested, ignore socket errors */
1116 if (test_bit(NBD_DISCONNECT_REQUESTED, &config->runtime_flags))
1117 ret = 0;
1118 if (test_bit(NBD_TIMEDOUT, &config->runtime_flags))
1119 ret = -ETIMEDOUT;
1120 return ret;
1121 }
1122
1123 static void nbd_clear_sock_ioctl(struct nbd_device *nbd,
1124 struct block_device *bdev)
1125 {
1126 sock_shutdown(nbd);
1127 kill_bdev(bdev);
1128 nbd_bdev_reset(bdev);
1129 if (test_and_clear_bit(NBD_HAS_CONFIG_REF,
1130 &nbd->config->runtime_flags))
1131 nbd_config_put(nbd);
1132 }
1133
1134 /* Must be called with config_lock held */
1135 static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
1136 unsigned int cmd, unsigned long arg)
1137 {
1138 struct nbd_config *config = nbd->config;
1139
1140 switch (cmd) {
1141 case NBD_DISCONNECT:
1142 return nbd_disconnect(nbd);
1143 case NBD_CLEAR_SOCK:
1144 nbd_clear_sock_ioctl(nbd, bdev);
1145 return 0;
1146 case NBD_SET_SOCK:
1147 return nbd_add_socket(nbd, arg, false);
1148 case NBD_SET_BLKSIZE:
1149 nbd_size_set(nbd, arg,
1150 div_s64(config->bytesize, arg));
1151 return 0;
1152 case NBD_SET_SIZE:
1153 nbd_size_set(nbd, config->blksize,
1154 div_s64(arg, config->blksize));
1155 return 0;
1156 case NBD_SET_SIZE_BLOCKS:
1157 nbd_size_set(nbd, config->blksize, arg);
1158 return 0;
1159 case NBD_SET_TIMEOUT:
1160 if (arg) {
1161 nbd->tag_set.timeout = arg * HZ;
1162 blk_queue_rq_timeout(nbd->disk->queue, arg * HZ);
1163 }
1164 return 0;
1165
1166 case NBD_SET_FLAGS:
1167 config->flags = arg;
1168 return 0;
1169 case NBD_DO_IT:
1170 return nbd_start_device_ioctl(nbd, bdev);
1171 case NBD_CLEAR_QUE:
1172 /*
1173 * This is for compatibility only. The queue is always cleared
1174 * by NBD_DO_IT or NBD_CLEAR_SOCK.
1175 */
1176 return 0;
1177 case NBD_PRINT_DEBUG:
1178 /*
1179 * For compatibility only, we no longer keep a list of
1180 * outstanding requests.
1181 */
1182 return 0;
1183 }
1184 return -ENOTTY;
1185 }
1186
1187 static int nbd_ioctl(struct block_device *bdev, fmode_t mode,
1188 unsigned int cmd, unsigned long arg)
1189 {
1190 struct nbd_device *nbd = bdev->bd_disk->private_data;
1191 struct nbd_config *config = nbd->config;
1192 int error = -EINVAL;
1193
1194 if (!capable(CAP_SYS_ADMIN))
1195 return -EPERM;
1196
1197 mutex_lock(&nbd->config_lock);
1198
1199 /* Don't allow ioctl operations on a nbd device that was created with
1200 * netlink, unless it's DISCONNECT or CLEAR_SOCK, which are fine.
1201 */
1202 if (!test_bit(NBD_BOUND, &config->runtime_flags) ||
1203 (cmd == NBD_DISCONNECT || cmd == NBD_CLEAR_SOCK))
1204 error = __nbd_ioctl(bdev, nbd, cmd, arg);
1205 else
1206 dev_err(nbd_to_dev(nbd), "Cannot use ioctl interface on a netlink controlled device.\n");
1207 mutex_unlock(&nbd->config_lock);
1208 return error;
1209 }
1210
1211 static struct nbd_config *nbd_alloc_config(void)
1212 {
1213 struct nbd_config *config;
1214
1215 config = kzalloc(sizeof(struct nbd_config), GFP_NOFS);
1216 if (!config)
1217 return NULL;
1218 atomic_set(&config->recv_threads, 0);
1219 init_waitqueue_head(&config->recv_wq);
1220 init_waitqueue_head(&config->conn_wait);
1221 config->blksize = 1024;
1222 atomic_set(&config->live_connections, 0);
1223 try_module_get(THIS_MODULE);
1224 return config;
1225 }
1226
1227 static int nbd_open(struct block_device *bdev, fmode_t mode)
1228 {
1229 struct nbd_device *nbd;
1230 int ret = 0;
1231
1232 mutex_lock(&nbd_index_mutex);
1233 nbd = bdev->bd_disk->private_data;
1234 if (!nbd) {
1235 ret = -ENXIO;
1236 goto out;
1237 }
1238 if (!refcount_inc_not_zero(&nbd->refs)) {
1239 ret = -ENXIO;
1240 goto out;
1241 }
1242 if (!refcount_inc_not_zero(&nbd->config_refs)) {
1243 struct nbd_config *config;
1244
1245 mutex_lock(&nbd->config_lock);
1246 if (refcount_inc_not_zero(&nbd->config_refs)) {
1247 mutex_unlock(&nbd->config_lock);
1248 goto out;
1249 }
1250 config = nbd->config = nbd_alloc_config();
1251 if (!config) {
1252 ret = -ENOMEM;
1253 mutex_unlock(&nbd->config_lock);
1254 goto out;
1255 }
1256 refcount_set(&nbd->config_refs, 1);
1257 refcount_inc(&nbd->refs);
1258 mutex_unlock(&nbd->config_lock);
1259 }
1260 out:
1261 mutex_unlock(&nbd_index_mutex);
1262 return ret;
1263 }
1264
1265 static void nbd_release(struct gendisk *disk, fmode_t mode)
1266 {
1267 struct nbd_device *nbd = disk->private_data;
1268 nbd_config_put(nbd);
1269 nbd_put(nbd);
1270 }
1271
1272 static const struct block_device_operations nbd_fops =
1273 {
1274 .owner = THIS_MODULE,
1275 .open = nbd_open,
1276 .release = nbd_release,
1277 .ioctl = nbd_ioctl,
1278 .compat_ioctl = nbd_ioctl,
1279 };
1280
1281 #if IS_ENABLED(CONFIG_DEBUG_FS)
1282
1283 static int nbd_dbg_tasks_show(struct seq_file *s, void *unused)
1284 {
1285 struct nbd_device *nbd = s->private;
1286
1287 if (nbd->task_recv)
1288 seq_printf(s, "recv: %d\n", task_pid_nr(nbd->task_recv));
1289
1290 return 0;
1291 }
1292
1293 static int nbd_dbg_tasks_open(struct inode *inode, struct file *file)
1294 {
1295 return single_open(file, nbd_dbg_tasks_show, inode->i_private);
1296 }
1297
1298 static const struct file_operations nbd_dbg_tasks_ops = {
1299 .open = nbd_dbg_tasks_open,
1300 .read = seq_read,
1301 .llseek = seq_lseek,
1302 .release = single_release,
1303 };
1304
1305 static int nbd_dbg_flags_show(struct seq_file *s, void *unused)
1306 {
1307 struct nbd_device *nbd = s->private;
1308 u32 flags = nbd->config->flags;
1309
1310 seq_printf(s, "Hex: 0x%08x\n\n", flags);
1311
1312 seq_puts(s, "Known flags:\n");
1313
1314 if (flags & NBD_FLAG_HAS_FLAGS)
1315 seq_puts(s, "NBD_FLAG_HAS_FLAGS\n");
1316 if (flags & NBD_FLAG_READ_ONLY)
1317 seq_puts(s, "NBD_FLAG_READ_ONLY\n");
1318 if (flags & NBD_FLAG_SEND_FLUSH)
1319 seq_puts(s, "NBD_FLAG_SEND_FLUSH\n");
1320 if (flags & NBD_FLAG_SEND_FUA)
1321 seq_puts(s, "NBD_FLAG_SEND_FUA\n");
1322 if (flags & NBD_FLAG_SEND_TRIM)
1323 seq_puts(s, "NBD_FLAG_SEND_TRIM\n");
1324
1325 return 0;
1326 }
1327
1328 static int nbd_dbg_flags_open(struct inode *inode, struct file *file)
1329 {
1330 return single_open(file, nbd_dbg_flags_show, inode->i_private);
1331 }
1332
1333 static const struct file_operations nbd_dbg_flags_ops = {
1334 .open = nbd_dbg_flags_open,
1335 .read = seq_read,
1336 .llseek = seq_lseek,
1337 .release = single_release,
1338 };
1339
1340 static int nbd_dev_dbg_init(struct nbd_device *nbd)
1341 {
1342 struct dentry *dir;
1343 struct nbd_config *config = nbd->config;
1344
1345 if (!nbd_dbg_dir)
1346 return -EIO;
1347
1348 dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir);
1349 if (!dir) {
1350 dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s'\n",
1351 nbd_name(nbd));
1352 return -EIO;
1353 }
1354 config->dbg_dir = dir;
1355
1356 debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_ops);
1357 debugfs_create_u64("size_bytes", 0444, dir, &config->bytesize);
1358 debugfs_create_u32("timeout", 0444, dir, &nbd->tag_set.timeout);
1359 debugfs_create_u64("blocksize", 0444, dir, &config->blksize);
1360 debugfs_create_file("flags", 0444, dir, nbd, &nbd_dbg_flags_ops);
1361
1362 return 0;
1363 }
1364
1365 static void nbd_dev_dbg_close(struct nbd_device *nbd)
1366 {
1367 debugfs_remove_recursive(nbd->config->dbg_dir);
1368 }
1369
1370 static int nbd_dbg_init(void)
1371 {
1372 struct dentry *dbg_dir;
1373
1374 dbg_dir = debugfs_create_dir("nbd", NULL);
1375 if (!dbg_dir)
1376 return -EIO;
1377
1378 nbd_dbg_dir = dbg_dir;
1379
1380 return 0;
1381 }
1382
1383 static void nbd_dbg_close(void)
1384 {
1385 debugfs_remove_recursive(nbd_dbg_dir);
1386 }
1387
1388 #else /* IS_ENABLED(CONFIG_DEBUG_FS) */
1389
1390 static int nbd_dev_dbg_init(struct nbd_device *nbd)
1391 {
1392 return 0;
1393 }
1394
1395 static void nbd_dev_dbg_close(struct nbd_device *nbd)
1396 {
1397 }
1398
1399 static int nbd_dbg_init(void)
1400 {
1401 return 0;
1402 }
1403
1404 static void nbd_dbg_close(void)
1405 {
1406 }
1407
1408 #endif
1409
1410 static int nbd_init_request(struct blk_mq_tag_set *set, struct request *rq,
1411 unsigned int hctx_idx, unsigned int numa_node)
1412 {
1413 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq);
1414 cmd->nbd = set->driver_data;
1415 return 0;
1416 }
1417
1418 static const struct blk_mq_ops nbd_mq_ops = {
1419 .queue_rq = nbd_queue_rq,
1420 .complete = nbd_complete_rq,
1421 .init_request = nbd_init_request,
1422 .timeout = nbd_xmit_timeout,
1423 };
1424
1425 static int nbd_dev_add(int index)
1426 {
1427 struct nbd_device *nbd;
1428 struct gendisk *disk;
1429 struct request_queue *q;
1430 int err = -ENOMEM;
1431
1432 nbd = kzalloc(sizeof(struct nbd_device), GFP_KERNEL);
1433 if (!nbd)
1434 goto out;
1435
1436 disk = alloc_disk(1 << part_shift);
1437 if (!disk)
1438 goto out_free_nbd;
1439
1440 if (index >= 0) {
1441 err = idr_alloc(&nbd_index_idr, nbd, index, index + 1,
1442 GFP_KERNEL);
1443 if (err == -ENOSPC)
1444 err = -EEXIST;
1445 } else {
1446 err = idr_alloc(&nbd_index_idr, nbd, 0, 0, GFP_KERNEL);
1447 if (err >= 0)
1448 index = err;
1449 }
1450 if (err < 0)
1451 goto out_free_disk;
1452
1453 nbd->index = index;
1454 nbd->disk = disk;
1455 nbd->tag_set.ops = &nbd_mq_ops;
1456 nbd->tag_set.nr_hw_queues = 1;
1457 nbd->tag_set.queue_depth = 128;
1458 nbd->tag_set.numa_node = NUMA_NO_NODE;
1459 nbd->tag_set.cmd_size = sizeof(struct nbd_cmd);
1460 nbd->tag_set.flags = BLK_MQ_F_SHOULD_MERGE |
1461 BLK_MQ_F_SG_MERGE | BLK_MQ_F_BLOCKING;
1462 nbd->tag_set.driver_data = nbd;
1463
1464 err = blk_mq_alloc_tag_set(&nbd->tag_set);
1465 if (err)
1466 goto out_free_idr;
1467
1468 q = blk_mq_init_queue(&nbd->tag_set);
1469 if (IS_ERR(q)) {
1470 err = PTR_ERR(q);
1471 goto out_free_tags;
1472 }
1473 disk->queue = q;
1474
1475 /*
1476 * Tell the block layer that we are not a rotational device
1477 */
1478 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue);
1479 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, disk->queue);
1480 disk->queue->limits.discard_granularity = 512;
1481 blk_queue_max_discard_sectors(disk->queue, UINT_MAX);
1482 blk_queue_max_segment_size(disk->queue, UINT_MAX);
1483 blk_queue_max_segments(disk->queue, USHRT_MAX);
1484 blk_queue_max_hw_sectors(disk->queue, 65536);
1485 disk->queue->limits.max_sectors = 256;
1486
1487 mutex_init(&nbd->config_lock);
1488 refcount_set(&nbd->config_refs, 0);
1489 refcount_set(&nbd->refs, 1);
1490 INIT_LIST_HEAD(&nbd->list);
1491 disk->major = NBD_MAJOR;
1492 disk->first_minor = index << part_shift;
1493 disk->fops = &nbd_fops;
1494 disk->private_data = nbd;
1495 sprintf(disk->disk_name, "nbd%d", index);
1496 add_disk(disk);
1497 nbd_total_devices++;
1498 return index;
1499
1500 out_free_tags:
1501 blk_mq_free_tag_set(&nbd->tag_set);
1502 out_free_idr:
1503 idr_remove(&nbd_index_idr, index);
1504 out_free_disk:
1505 put_disk(disk);
1506 out_free_nbd:
1507 kfree(nbd);
1508 out:
1509 return err;
1510 }
1511
1512 static int find_free_cb(int id, void *ptr, void *data)
1513 {
1514 struct nbd_device *nbd = ptr;
1515 struct nbd_device **found = data;
1516
1517 if (!refcount_read(&nbd->config_refs)) {
1518 *found = nbd;
1519 return 1;
1520 }
1521 return 0;
1522 }
1523
1524 /* Netlink interface. */
1525 static struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = {
1526 [NBD_ATTR_INDEX] = { .type = NLA_U32 },
1527 [NBD_ATTR_SIZE_BYTES] = { .type = NLA_U64 },
1528 [NBD_ATTR_BLOCK_SIZE_BYTES] = { .type = NLA_U64 },
1529 [NBD_ATTR_TIMEOUT] = { .type = NLA_U64 },
1530 [NBD_ATTR_SERVER_FLAGS] = { .type = NLA_U64 },
1531 [NBD_ATTR_CLIENT_FLAGS] = { .type = NLA_U64 },
1532 [NBD_ATTR_SOCKETS] = { .type = NLA_NESTED},
1533 [NBD_ATTR_DEAD_CONN_TIMEOUT] = { .type = NLA_U64 },
1534 [NBD_ATTR_DEVICE_LIST] = { .type = NLA_NESTED},
1535 };
1536
1537 static struct nla_policy nbd_sock_policy[NBD_SOCK_MAX + 1] = {
1538 [NBD_SOCK_FD] = { .type = NLA_U32 },
1539 };
1540
1541 /* We don't use this right now since we don't parse the incoming list, but we
1542 * still want it here so userspace knows what to expect.
1543 */
1544 static struct nla_policy __attribute__((unused))
1545 nbd_device_policy[NBD_DEVICE_ATTR_MAX + 1] = {
1546 [NBD_DEVICE_INDEX] = { .type = NLA_U32 },
1547 [NBD_DEVICE_CONNECTED] = { .type = NLA_U8 },
1548 };
1549
1550 static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
1551 {
1552 struct nbd_device *nbd = NULL;
1553 struct nbd_config *config;
1554 int index = -1;
1555 int ret;
1556 bool put_dev = false;
1557
1558 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1559 return -EPERM;
1560
1561 if (info->attrs[NBD_ATTR_INDEX])
1562 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1563 if (!info->attrs[NBD_ATTR_SOCKETS]) {
1564 printk(KERN_ERR "nbd: must specify at least one socket\n");
1565 return -EINVAL;
1566 }
1567 if (!info->attrs[NBD_ATTR_SIZE_BYTES]) {
1568 printk(KERN_ERR "nbd: must specify a size in bytes for the device\n");
1569 return -EINVAL;
1570 }
1571 again:
1572 mutex_lock(&nbd_index_mutex);
1573 if (index == -1) {
1574 ret = idr_for_each(&nbd_index_idr, &find_free_cb, &nbd);
1575 if (ret == 0) {
1576 int new_index;
1577 new_index = nbd_dev_add(-1);
1578 if (new_index < 0) {
1579 mutex_unlock(&nbd_index_mutex);
1580 printk(KERN_ERR "nbd: failed to add new device\n");
1581 return ret;
1582 }
1583 nbd = idr_find(&nbd_index_idr, new_index);
1584 }
1585 } else {
1586 nbd = idr_find(&nbd_index_idr, index);
1587 }
1588 if (!nbd) {
1589 printk(KERN_ERR "nbd: couldn't find device at index %d\n",
1590 index);
1591 mutex_unlock(&nbd_index_mutex);
1592 return -EINVAL;
1593 }
1594 if (!refcount_inc_not_zero(&nbd->refs)) {
1595 mutex_unlock(&nbd_index_mutex);
1596 if (index == -1)
1597 goto again;
1598 printk(KERN_ERR "nbd: device at index %d is going down\n",
1599 index);
1600 return -EINVAL;
1601 }
1602 mutex_unlock(&nbd_index_mutex);
1603
1604 mutex_lock(&nbd->config_lock);
1605 if (refcount_read(&nbd->config_refs)) {
1606 mutex_unlock(&nbd->config_lock);
1607 nbd_put(nbd);
1608 if (index == -1)
1609 goto again;
1610 printk(KERN_ERR "nbd: nbd%d already in use\n", index);
1611 return -EBUSY;
1612 }
1613 if (WARN_ON(nbd->config)) {
1614 mutex_unlock(&nbd->config_lock);
1615 nbd_put(nbd);
1616 return -EINVAL;
1617 }
1618 config = nbd->config = nbd_alloc_config();
1619 if (!nbd->config) {
1620 mutex_unlock(&nbd->config_lock);
1621 nbd_put(nbd);
1622 printk(KERN_ERR "nbd: couldn't allocate config\n");
1623 return -ENOMEM;
1624 }
1625 refcount_set(&nbd->config_refs, 1);
1626 set_bit(NBD_BOUND, &config->runtime_flags);
1627
1628 if (info->attrs[NBD_ATTR_SIZE_BYTES]) {
1629 u64 bytes = nla_get_u64(info->attrs[NBD_ATTR_SIZE_BYTES]);
1630 nbd_size_set(nbd, config->blksize,
1631 div64_u64(bytes, config->blksize));
1632 }
1633 if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]) {
1634 u64 bsize =
1635 nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]);
1636 nbd_size_set(nbd, bsize, div64_u64(config->bytesize, bsize));
1637 }
1638 if (info->attrs[NBD_ATTR_TIMEOUT]) {
1639 u64 timeout = nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]);
1640 nbd->tag_set.timeout = timeout * HZ;
1641 blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ);
1642 }
1643 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
1644 config->dead_conn_timeout =
1645 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
1646 config->dead_conn_timeout *= HZ;
1647 }
1648 if (info->attrs[NBD_ATTR_SERVER_FLAGS])
1649 config->flags =
1650 nla_get_u64(info->attrs[NBD_ATTR_SERVER_FLAGS]);
1651 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
1652 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
1653 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
1654 set_bit(NBD_DESTROY_ON_DISCONNECT,
1655 &config->runtime_flags);
1656 put_dev = true;
1657 }
1658 }
1659
1660 if (info->attrs[NBD_ATTR_SOCKETS]) {
1661 struct nlattr *attr;
1662 int rem, fd;
1663
1664 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
1665 rem) {
1666 struct nlattr *socks[NBD_SOCK_MAX+1];
1667
1668 if (nla_type(attr) != NBD_SOCK_ITEM) {
1669 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");
1670 ret = -EINVAL;
1671 goto out;
1672 }
1673 ret = nla_parse_nested(socks, NBD_SOCK_MAX, attr,
1674 nbd_sock_policy, info->extack);
1675 if (ret != 0) {
1676 printk(KERN_ERR "nbd: error processing sock list\n");
1677 ret = -EINVAL;
1678 goto out;
1679 }
1680 if (!socks[NBD_SOCK_FD])
1681 continue;
1682 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
1683 ret = nbd_add_socket(nbd, fd, true);
1684 if (ret)
1685 goto out;
1686 }
1687 }
1688 ret = nbd_start_device(nbd);
1689 out:
1690 mutex_unlock(&nbd->config_lock);
1691 if (!ret) {
1692 set_bit(NBD_HAS_CONFIG_REF, &config->runtime_flags);
1693 refcount_inc(&nbd->config_refs);
1694 nbd_connect_reply(info, nbd->index);
1695 }
1696 nbd_config_put(nbd);
1697 if (put_dev)
1698 nbd_put(nbd);
1699 return ret;
1700 }
1701
1702 static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info)
1703 {
1704 struct nbd_device *nbd;
1705 int index;
1706
1707 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1708 return -EPERM;
1709
1710 if (!info->attrs[NBD_ATTR_INDEX]) {
1711 printk(KERN_ERR "nbd: must specify an index to disconnect\n");
1712 return -EINVAL;
1713 }
1714 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1715 mutex_lock(&nbd_index_mutex);
1716 nbd = idr_find(&nbd_index_idr, index);
1717 if (!nbd) {
1718 mutex_unlock(&nbd_index_mutex);
1719 printk(KERN_ERR "nbd: couldn't find device at index %d\n",
1720 index);
1721 return -EINVAL;
1722 }
1723 if (!refcount_inc_not_zero(&nbd->refs)) {
1724 mutex_unlock(&nbd_index_mutex);
1725 printk(KERN_ERR "nbd: device at index %d is going down\n",
1726 index);
1727 return -EINVAL;
1728 }
1729 mutex_unlock(&nbd_index_mutex);
1730 if (!refcount_inc_not_zero(&nbd->config_refs)) {
1731 nbd_put(nbd);
1732 return 0;
1733 }
1734 mutex_lock(&nbd->config_lock);
1735 nbd_disconnect(nbd);
1736 mutex_unlock(&nbd->config_lock);
1737 if (test_and_clear_bit(NBD_HAS_CONFIG_REF,
1738 &nbd->config->runtime_flags))
1739 nbd_config_put(nbd);
1740 nbd_config_put(nbd);
1741 nbd_put(nbd);
1742 return 0;
1743 }
1744
1745 static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info)
1746 {
1747 struct nbd_device *nbd = NULL;
1748 struct nbd_config *config;
1749 int index;
1750 int ret = -EINVAL;
1751 bool put_dev = false;
1752
1753 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1754 return -EPERM;
1755
1756 if (!info->attrs[NBD_ATTR_INDEX]) {
1757 printk(KERN_ERR "nbd: must specify a device to reconfigure\n");
1758 return -EINVAL;
1759 }
1760 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1761 mutex_lock(&nbd_index_mutex);
1762 nbd = idr_find(&nbd_index_idr, index);
1763 if (!nbd) {
1764 mutex_unlock(&nbd_index_mutex);
1765 printk(KERN_ERR "nbd: couldn't find a device at index %d\n",
1766 index);
1767 return -EINVAL;
1768 }
1769 if (!refcount_inc_not_zero(&nbd->refs)) {
1770 mutex_unlock(&nbd_index_mutex);
1771 printk(KERN_ERR "nbd: device at index %d is going down\n",
1772 index);
1773 return -EINVAL;
1774 }
1775 mutex_unlock(&nbd_index_mutex);
1776
1777 if (!refcount_inc_not_zero(&nbd->config_refs)) {
1778 dev_err(nbd_to_dev(nbd),
1779 "not configured, cannot reconfigure\n");
1780 nbd_put(nbd);
1781 return -EINVAL;
1782 }
1783
1784 mutex_lock(&nbd->config_lock);
1785 config = nbd->config;
1786 if (!test_bit(NBD_BOUND, &config->runtime_flags) ||
1787 !nbd->task_recv) {
1788 dev_err(nbd_to_dev(nbd),
1789 "not configured, cannot reconfigure\n");
1790 goto out;
1791 }
1792
1793 if (info->attrs[NBD_ATTR_TIMEOUT]) {
1794 u64 timeout = nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]);
1795 nbd->tag_set.timeout = timeout * HZ;
1796 blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ);
1797 }
1798 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
1799 config->dead_conn_timeout =
1800 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
1801 config->dead_conn_timeout *= HZ;
1802 }
1803 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
1804 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
1805 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
1806 if (!test_and_set_bit(NBD_DESTROY_ON_DISCONNECT,
1807 &config->runtime_flags))
1808 put_dev = true;
1809 } else {
1810 if (test_and_clear_bit(NBD_DESTROY_ON_DISCONNECT,
1811 &config->runtime_flags))
1812 refcount_inc(&nbd->refs);
1813 }
1814 }
1815
1816 if (info->attrs[NBD_ATTR_SOCKETS]) {
1817 struct nlattr *attr;
1818 int rem, fd;
1819
1820 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
1821 rem) {
1822 struct nlattr *socks[NBD_SOCK_MAX+1];
1823
1824 if (nla_type(attr) != NBD_SOCK_ITEM) {
1825 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");
1826 ret = -EINVAL;
1827 goto out;
1828 }
1829 ret = nla_parse_nested(socks, NBD_SOCK_MAX, attr,
1830 nbd_sock_policy, info->extack);
1831 if (ret != 0) {
1832 printk(KERN_ERR "nbd: error processing sock list\n");
1833 ret = -EINVAL;
1834 goto out;
1835 }
1836 if (!socks[NBD_SOCK_FD])
1837 continue;
1838 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
1839 ret = nbd_reconnect_socket(nbd, fd);
1840 if (ret) {
1841 if (ret == -ENOSPC)
1842 ret = 0;
1843 goto out;
1844 }
1845 dev_info(nbd_to_dev(nbd), "reconnected socket\n");
1846 }
1847 }
1848 out:
1849 mutex_unlock(&nbd->config_lock);
1850 nbd_config_put(nbd);
1851 nbd_put(nbd);
1852 if (put_dev)
1853 nbd_put(nbd);
1854 return ret;
1855 }
1856
1857 static const struct genl_ops nbd_connect_genl_ops[] = {
1858 {
1859 .cmd = NBD_CMD_CONNECT,
1860 .policy = nbd_attr_policy,
1861 .doit = nbd_genl_connect,
1862 },
1863 {
1864 .cmd = NBD_CMD_DISCONNECT,
1865 .policy = nbd_attr_policy,
1866 .doit = nbd_genl_disconnect,
1867 },
1868 {
1869 .cmd = NBD_CMD_RECONFIGURE,
1870 .policy = nbd_attr_policy,
1871 .doit = nbd_genl_reconfigure,
1872 },
1873 {
1874 .cmd = NBD_CMD_STATUS,
1875 .policy = nbd_attr_policy,
1876 .doit = nbd_genl_status,
1877 },
1878 };
1879
1880 static const struct genl_multicast_group nbd_mcast_grps[] = {
1881 { .name = NBD_GENL_MCAST_GROUP_NAME, },
1882 };
1883
1884 static struct genl_family nbd_genl_family __ro_after_init = {
1885 .hdrsize = 0,
1886 .name = NBD_GENL_FAMILY_NAME,
1887 .version = NBD_GENL_VERSION,
1888 .module = THIS_MODULE,
1889 .ops = nbd_connect_genl_ops,
1890 .n_ops = ARRAY_SIZE(nbd_connect_genl_ops),
1891 .maxattr = NBD_ATTR_MAX,
1892 .mcgrps = nbd_mcast_grps,
1893 .n_mcgrps = ARRAY_SIZE(nbd_mcast_grps),
1894 };
1895
1896 static int populate_nbd_status(struct nbd_device *nbd, struct sk_buff *reply)
1897 {
1898 struct nlattr *dev_opt;
1899 u8 connected = 0;
1900 int ret;
1901
1902 /* This is a little racey, but for status it's ok. The
1903 * reason we don't take a ref here is because we can't
1904 * take a ref in the index == -1 case as we would need
1905 * to put under the nbd_index_mutex, which could
1906 * deadlock if we are configured to remove ourselves
1907 * once we're disconnected.
1908 */
1909 if (refcount_read(&nbd->config_refs))
1910 connected = 1;
1911 dev_opt = nla_nest_start(reply, NBD_DEVICE_ITEM);
1912 if (!dev_opt)
1913 return -EMSGSIZE;
1914 ret = nla_put_u32(reply, NBD_DEVICE_INDEX, nbd->index);
1915 if (ret)
1916 return -EMSGSIZE;
1917 ret = nla_put_u8(reply, NBD_DEVICE_CONNECTED,
1918 connected);
1919 if (ret)
1920 return -EMSGSIZE;
1921 nla_nest_end(reply, dev_opt);
1922 return 0;
1923 }
1924
1925 static int status_cb(int id, void *ptr, void *data)
1926 {
1927 struct nbd_device *nbd = ptr;
1928 return populate_nbd_status(nbd, (struct sk_buff *)data);
1929 }
1930
1931 static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info)
1932 {
1933 struct nlattr *dev_list;
1934 struct sk_buff *reply;
1935 void *reply_head;
1936 size_t msg_size;
1937 int index = -1;
1938 int ret = -ENOMEM;
1939
1940 if (info->attrs[NBD_ATTR_INDEX])
1941 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1942
1943 mutex_lock(&nbd_index_mutex);
1944
1945 msg_size = nla_total_size(nla_attr_size(sizeof(u32)) +
1946 nla_attr_size(sizeof(u8)));
1947 msg_size *= (index == -1) ? nbd_total_devices : 1;
1948
1949 reply = genlmsg_new(msg_size, GFP_KERNEL);
1950 if (!reply)
1951 goto out;
1952 reply_head = genlmsg_put_reply(reply, info, &nbd_genl_family, 0,
1953 NBD_CMD_STATUS);
1954 if (!reply_head) {
1955 nlmsg_free(reply);
1956 goto out;
1957 }
1958
1959 dev_list = nla_nest_start(reply, NBD_ATTR_DEVICE_LIST);
1960 if (index == -1) {
1961 ret = idr_for_each(&nbd_index_idr, &status_cb, reply);
1962 if (ret) {
1963 nlmsg_free(reply);
1964 goto out;
1965 }
1966 } else {
1967 struct nbd_device *nbd;
1968 nbd = idr_find(&nbd_index_idr, index);
1969 if (nbd) {
1970 ret = populate_nbd_status(nbd, reply);
1971 if (ret) {
1972 nlmsg_free(reply);
1973 goto out;
1974 }
1975 }
1976 }
1977 nla_nest_end(reply, dev_list);
1978 genlmsg_end(reply, reply_head);
1979 genlmsg_reply(reply, info);
1980 ret = 0;
1981 out:
1982 mutex_unlock(&nbd_index_mutex);
1983 return ret;
1984 }
1985
1986 static void nbd_connect_reply(struct genl_info *info, int index)
1987 {
1988 struct sk_buff *skb;
1989 void *msg_head;
1990 int ret;
1991
1992 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
1993 if (!skb)
1994 return;
1995 msg_head = genlmsg_put_reply(skb, info, &nbd_genl_family, 0,
1996 NBD_CMD_CONNECT);
1997 if (!msg_head) {
1998 nlmsg_free(skb);
1999 return;
2000 }
2001 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2002 if (ret) {
2003 nlmsg_free(skb);
2004 return;
2005 }
2006 genlmsg_end(skb, msg_head);
2007 genlmsg_reply(skb, info);
2008 }
2009
2010 static void nbd_mcast_index(int index)
2011 {
2012 struct sk_buff *skb;
2013 void *msg_head;
2014 int ret;
2015
2016 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2017 if (!skb)
2018 return;
2019 msg_head = genlmsg_put(skb, 0, 0, &nbd_genl_family, 0,
2020 NBD_CMD_LINK_DEAD);
2021 if (!msg_head) {
2022 nlmsg_free(skb);
2023 return;
2024 }
2025 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2026 if (ret) {
2027 nlmsg_free(skb);
2028 return;
2029 }
2030 genlmsg_end(skb, msg_head);
2031 genlmsg_multicast(&nbd_genl_family, skb, 0, 0, GFP_KERNEL);
2032 }
2033
2034 static void nbd_dead_link_work(struct work_struct *work)
2035 {
2036 struct link_dead_args *args = container_of(work, struct link_dead_args,
2037 work);
2038 nbd_mcast_index(args->index);
2039 kfree(args);
2040 }
2041
2042 static int __init nbd_init(void)
2043 {
2044 int i;
2045
2046 BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
2047
2048 if (max_part < 0) {
2049 printk(KERN_ERR "nbd: max_part must be >= 0\n");
2050 return -EINVAL;
2051 }
2052
2053 part_shift = 0;
2054 if (max_part > 0) {
2055 part_shift = fls(max_part);
2056
2057 /*
2058 * Adjust max_part according to part_shift as it is exported
2059 * to user space so that user can know the max number of
2060 * partition kernel should be able to manage.
2061 *
2062 * Note that -1 is required because partition 0 is reserved
2063 * for the whole disk.
2064 */
2065 max_part = (1UL << part_shift) - 1;
2066 }
2067
2068 if ((1UL << part_shift) > DISK_MAX_PARTS)
2069 return -EINVAL;
2070
2071 if (nbds_max > 1UL << (MINORBITS - part_shift))
2072 return -EINVAL;
2073 recv_workqueue = alloc_workqueue("knbd-recv",
2074 WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
2075 if (!recv_workqueue)
2076 return -ENOMEM;
2077
2078 if (register_blkdev(NBD_MAJOR, "nbd")) {
2079 destroy_workqueue(recv_workqueue);
2080 return -EIO;
2081 }
2082
2083 if (genl_register_family(&nbd_genl_family)) {
2084 unregister_blkdev(NBD_MAJOR, "nbd");
2085 destroy_workqueue(recv_workqueue);
2086 return -EINVAL;
2087 }
2088 nbd_dbg_init();
2089
2090 mutex_lock(&nbd_index_mutex);
2091 for (i = 0; i < nbds_max; i++)
2092 nbd_dev_add(i);
2093 mutex_unlock(&nbd_index_mutex);
2094 return 0;
2095 }
2096
2097 static int nbd_exit_cb(int id, void *ptr, void *data)
2098 {
2099 struct list_head *list = (struct list_head *)data;
2100 struct nbd_device *nbd = ptr;
2101
2102 list_add_tail(&nbd->list, list);
2103 return 0;
2104 }
2105
2106 static void __exit nbd_cleanup(void)
2107 {
2108 struct nbd_device *nbd;
2109 LIST_HEAD(del_list);
2110
2111 nbd_dbg_close();
2112
2113 mutex_lock(&nbd_index_mutex);
2114 idr_for_each(&nbd_index_idr, &nbd_exit_cb, &del_list);
2115 mutex_unlock(&nbd_index_mutex);
2116
2117 while (!list_empty(&del_list)) {
2118 nbd = list_first_entry(&del_list, struct nbd_device, list);
2119 list_del_init(&nbd->list);
2120 if (refcount_read(&nbd->refs) != 1)
2121 printk(KERN_ERR "nbd: possibly leaking a device\n");
2122 nbd_put(nbd);
2123 }
2124
2125 idr_destroy(&nbd_index_idr);
2126 genl_unregister_family(&nbd_genl_family);
2127 destroy_workqueue(recv_workqueue);
2128 unregister_blkdev(NBD_MAJOR, "nbd");
2129 }
2130
2131 module_init(nbd_init);
2132 module_exit(nbd_cleanup);
2133
2134 MODULE_DESCRIPTION("Network Block Device");
2135 MODULE_LICENSE("GPL");
2136
2137 module_param(nbds_max, int, 0444);
2138 MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
2139 module_param(max_part, int, 0444);
2140 MODULE_PARM_DESC(max_part, "number of partitions per device (default: 0)");
Ubuntu Artful kernel mirror