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[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 = 15;
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 }
247
248 static void nbd_complete_rq(struct request *req)
249 {
250 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
251
252 dev_dbg(nbd_to_dev(cmd->nbd), "request %p: %s\n", cmd,
253 cmd->status ? "failed" : "done");
254
255 blk_mq_end_request(req, cmd->status);
256 }
257
258 /*
259 * Forcibly shutdown the socket causing all listeners to error
260 */
261 static void sock_shutdown(struct nbd_device *nbd)
262 {
263 struct nbd_config *config = nbd->config;
264 int i;
265
266 if (config->num_connections == 0)
267 return;
268 if (test_and_set_bit(NBD_DISCONNECTED, &config->runtime_flags))
269 return;
270
271 for (i = 0; i < config->num_connections; i++) {
272 struct nbd_sock *nsock = config->socks[i];
273 mutex_lock(&nsock->tx_lock);
274 nbd_mark_nsock_dead(nbd, nsock, 0);
275 mutex_unlock(&nsock->tx_lock);
276 }
277 dev_warn(disk_to_dev(nbd->disk), "shutting down sockets\n");
278 }
279
280 static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
281 bool reserved)
282 {
283 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
284 struct nbd_device *nbd = cmd->nbd;
285 struct nbd_config *config;
286
287 if (!refcount_inc_not_zero(&nbd->config_refs)) {
288 cmd->status = BLK_STS_TIMEOUT;
289 return BLK_EH_HANDLED;
290 }
291
292 /* If we are waiting on our dead timer then we could get timeout
293 * callbacks for our request. For this we just want to reset the timer
294 * and let the queue side take care of everything.
295 */
296 if (!completion_done(&cmd->send_complete)) {
297 nbd_config_put(nbd);
298 return BLK_EH_RESET_TIMER;
299 }
300 config = nbd->config;
301
302 if (config->num_connections > 1) {
303 dev_err_ratelimited(nbd_to_dev(nbd),
304 "Connection timed out, retrying\n");
305 /*
306 * Hooray we have more connections, requeue this IO, the submit
307 * path will put it on a real connection.
308 */
309 if (config->socks && config->num_connections > 1) {
310 if (cmd->index < config->num_connections) {
311 struct nbd_sock *nsock =
312 config->socks[cmd->index];
313 mutex_lock(&nsock->tx_lock);
314 /* We can have multiple outstanding requests, so
315 * we don't want to mark the nsock dead if we've
316 * already reconnected with a new socket, so
317 * only mark it dead if its the same socket we
318 * were sent out on.
319 */
320 if (cmd->cookie == nsock->cookie)
321 nbd_mark_nsock_dead(nbd, nsock, 1);
322 mutex_unlock(&nsock->tx_lock);
323 }
324 blk_mq_requeue_request(req, true);
325 nbd_config_put(nbd);
326 return BLK_EH_NOT_HANDLED;
327 }
328 } else {
329 dev_err_ratelimited(nbd_to_dev(nbd),
330 "Connection timed out\n");
331 }
332 set_bit(NBD_TIMEDOUT, &config->runtime_flags);
333 cmd->status = BLK_STS_IOERR;
334 sock_shutdown(nbd);
335 nbd_config_put(nbd);
336
337 return BLK_EH_HANDLED;
338 }
339
340 /*
341 * Send or receive packet.
342 */
343 static int sock_xmit(struct nbd_device *nbd, int index, int send,
344 struct iov_iter *iter, int msg_flags, int *sent)
345 {
346 struct nbd_config *config = nbd->config;
347 struct socket *sock = config->socks[index]->sock;
348 int result;
349 struct msghdr msg;
350 unsigned int noreclaim_flag;
351
352 if (unlikely(!sock)) {
353 dev_err_ratelimited(disk_to_dev(nbd->disk),
354 "Attempted %s on closed socket in sock_xmit\n",
355 (send ? "send" : "recv"));
356 return -EINVAL;
357 }
358
359 msg.msg_iter = *iter;
360
361 noreclaim_flag = memalloc_noreclaim_save();
362 do {
363 sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC;
364 msg.msg_name = NULL;
365 msg.msg_namelen = 0;
366 msg.msg_control = NULL;
367 msg.msg_controllen = 0;
368 msg.msg_flags = msg_flags | MSG_NOSIGNAL;
369
370 if (send)
371 result = sock_sendmsg(sock, &msg);
372 else
373 result = sock_recvmsg(sock, &msg, msg.msg_flags);
374
375 if (result <= 0) {
376 if (result == 0)
377 result = -EPIPE; /* short read */
378 break;
379 }
380 if (sent)
381 *sent += result;
382 } while (msg_data_left(&msg));
383
384 memalloc_noreclaim_restore(noreclaim_flag);
385
386 return result;
387 }
388
389 /*
390 * Different settings for sk->sk_sndtimeo can result in different return values
391 * if there is a signal pending when we enter sendmsg, because reasons?
392 */
393 static inline int was_interrupted(int result)
394 {
395 return result == -ERESTARTSYS || result == -EINTR;
396 }
397
398 /* always call with the tx_lock held */
399 static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
400 {
401 struct request *req = blk_mq_rq_from_pdu(cmd);
402 struct nbd_config *config = nbd->config;
403 struct nbd_sock *nsock = config->socks[index];
404 int result;
405 struct nbd_request request = {.magic = htonl(NBD_REQUEST_MAGIC)};
406 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
407 struct iov_iter from;
408 unsigned long size = blk_rq_bytes(req);
409 struct bio *bio;
410 u32 type;
411 u32 nbd_cmd_flags = 0;
412 u32 tag = blk_mq_unique_tag(req);
413 int sent = nsock->sent, skip = 0;
414
415 iov_iter_kvec(&from, WRITE | ITER_KVEC, &iov, 1, sizeof(request));
416
417 switch (req_op(req)) {
418 case REQ_OP_DISCARD:
419 type = NBD_CMD_TRIM;
420 break;
421 case REQ_OP_FLUSH:
422 type = NBD_CMD_FLUSH;
423 break;
424 case REQ_OP_WRITE:
425 type = NBD_CMD_WRITE;
426 break;
427 case REQ_OP_READ:
428 type = NBD_CMD_READ;
429 break;
430 default:
431 return -EIO;
432 }
433
434 if (rq_data_dir(req) == WRITE &&
435 (config->flags & NBD_FLAG_READ_ONLY)) {
436 dev_err_ratelimited(disk_to_dev(nbd->disk),
437 "Write on read-only\n");
438 return -EIO;
439 }
440
441 if (req->cmd_flags & REQ_FUA)
442 nbd_cmd_flags |= NBD_CMD_FLAG_FUA;
443
444 /* We did a partial send previously, and we at least sent the whole
445 * request struct, so just go and send the rest of the pages in the
446 * request.
447 */
448 if (sent) {
449 if (sent >= sizeof(request)) {
450 skip = sent - sizeof(request);
451 goto send_pages;
452 }
453 iov_iter_advance(&from, sent);
454 }
455 cmd->index = index;
456 cmd->cookie = nsock->cookie;
457 request.type = htonl(type | nbd_cmd_flags);
458 if (type != NBD_CMD_FLUSH) {
459 request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
460 request.len = htonl(size);
461 }
462 memcpy(request.handle, &tag, sizeof(tag));
463
464 dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n",
465 cmd, nbdcmd_to_ascii(type),
466 (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req));
467 result = sock_xmit(nbd, index, 1, &from,
468 (type == NBD_CMD_WRITE) ? MSG_MORE : 0, &sent);
469 if (result <= 0) {
470 if (was_interrupted(result)) {
471 /* If we havne't sent anything we can just return BUSY,
472 * however if we have sent something we need to make
473 * sure we only allow this req to be sent until we are
474 * completely done.
475 */
476 if (sent) {
477 nsock->pending = req;
478 nsock->sent = sent;
479 }
480 return BLK_STS_RESOURCE;
481 }
482 dev_err_ratelimited(disk_to_dev(nbd->disk),
483 "Send control failed (result %d)\n", result);
484 return -EAGAIN;
485 }
486 send_pages:
487 if (type != NBD_CMD_WRITE)
488 goto out;
489
490 bio = req->bio;
491 while (bio) {
492 struct bio *next = bio->bi_next;
493 struct bvec_iter iter;
494 struct bio_vec bvec;
495
496 bio_for_each_segment(bvec, bio, iter) {
497 bool is_last = !next && bio_iter_last(bvec, iter);
498 int flags = is_last ? 0 : MSG_MORE;
499
500 dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n",
501 cmd, bvec.bv_len);
502 iov_iter_bvec(&from, ITER_BVEC | WRITE,
503 &bvec, 1, bvec.bv_len);
504 if (skip) {
505 if (skip >= iov_iter_count(&from)) {
506 skip -= iov_iter_count(&from);
507 continue;
508 }
509 iov_iter_advance(&from, skip);
510 skip = 0;
511 }
512 result = sock_xmit(nbd, index, 1, &from, flags, &sent);
513 if (result <= 0) {
514 if (was_interrupted(result)) {
515 /* We've already sent the header, we
516 * have no choice but to set pending and
517 * return BUSY.
518 */
519 nsock->pending = req;
520 nsock->sent = sent;
521 return BLK_STS_RESOURCE;
522 }
523 dev_err(disk_to_dev(nbd->disk),
524 "Send data failed (result %d)\n",
525 result);
526 return -EAGAIN;
527 }
528 /*
529 * The completion might already have come in,
530 * so break for the last one instead of letting
531 * the iterator do it. This prevents use-after-free
532 * of the bio.
533 */
534 if (is_last)
535 break;
536 }
537 bio = next;
538 }
539 out:
540 nsock->pending = NULL;
541 nsock->sent = 0;
542 return 0;
543 }
544
545 /* NULL returned = something went wrong, inform userspace */
546 static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
547 {
548 struct nbd_config *config = nbd->config;
549 int result;
550 struct nbd_reply reply;
551 struct nbd_cmd *cmd;
552 struct request *req = NULL;
553 u16 hwq;
554 u32 tag;
555 struct kvec iov = {.iov_base = &reply, .iov_len = sizeof(reply)};
556 struct iov_iter to;
557
558 reply.magic = 0;
559 iov_iter_kvec(&to, READ | ITER_KVEC, &iov, 1, sizeof(reply));
560 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
561 if (result <= 0) {
562 if (!nbd_disconnected(config))
563 dev_err(disk_to_dev(nbd->disk),
564 "Receive control failed (result %d)\n", result);
565 return ERR_PTR(result);
566 }
567
568 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) {
569 dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n",
570 (unsigned long)ntohl(reply.magic));
571 return ERR_PTR(-EPROTO);
572 }
573
574 memcpy(&tag, reply.handle, sizeof(u32));
575
576 hwq = blk_mq_unique_tag_to_hwq(tag);
577 if (hwq < nbd->tag_set.nr_hw_queues)
578 req = blk_mq_tag_to_rq(nbd->tag_set.tags[hwq],
579 blk_mq_unique_tag_to_tag(tag));
580 if (!req || !blk_mq_request_started(req)) {
581 dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%d) %p\n",
582 tag, req);
583 return ERR_PTR(-ENOENT);
584 }
585 cmd = blk_mq_rq_to_pdu(req);
586 if (ntohl(reply.error)) {
587 dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n",
588 ntohl(reply.error));
589 cmd->status = BLK_STS_IOERR;
590 return cmd;
591 }
592
593 dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", cmd);
594 if (rq_data_dir(req) != WRITE) {
595 struct req_iterator iter;
596 struct bio_vec bvec;
597
598 rq_for_each_segment(bvec, req, iter) {
599 iov_iter_bvec(&to, ITER_BVEC | READ,
600 &bvec, 1, bvec.bv_len);
601 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
602 if (result <= 0) {
603 dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
604 result);
605 /*
606 * If we've disconnected or we only have 1
607 * connection then we need to make sure we
608 * complete this request, otherwise error out
609 * and let the timeout stuff handle resubmitting
610 * this request onto another connection.
611 */
612 if (nbd_disconnected(config) ||
613 config->num_connections <= 1) {
614 cmd->status = BLK_STS_IOERR;
615 return cmd;
616 }
617 return ERR_PTR(-EIO);
618 }
619 dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n",
620 cmd, bvec.bv_len);
621 }
622 } else {
623 /* See the comment in nbd_queue_rq. */
624 wait_for_completion(&cmd->send_complete);
625 }
626 return cmd;
627 }
628
629 static void recv_work(struct work_struct *work)
630 {
631 struct recv_thread_args *args = container_of(work,
632 struct recv_thread_args,
633 work);
634 struct nbd_device *nbd = args->nbd;
635 struct nbd_config *config = nbd->config;
636 struct nbd_cmd *cmd;
637
638 while (1) {
639 cmd = nbd_read_stat(nbd, args->index);
640 if (IS_ERR(cmd)) {
641 struct nbd_sock *nsock = config->socks[args->index];
642
643 mutex_lock(&nsock->tx_lock);
644 nbd_mark_nsock_dead(nbd, nsock, 1);
645 mutex_unlock(&nsock->tx_lock);
646 break;
647 }
648
649 blk_mq_complete_request(blk_mq_rq_from_pdu(cmd));
650 }
651 atomic_dec(&config->recv_threads);
652 wake_up(&config->recv_wq);
653 nbd_config_put(nbd);
654 kfree(args);
655 }
656
657 static void nbd_clear_req(struct request *req, void *data, bool reserved)
658 {
659 struct nbd_cmd *cmd;
660
661 if (!blk_mq_request_started(req))
662 return;
663 cmd = blk_mq_rq_to_pdu(req);
664 cmd->status = BLK_STS_IOERR;
665 blk_mq_complete_request(req);
666 }
667
668 static void nbd_clear_que(struct nbd_device *nbd)
669 {
670 blk_mq_quiesce_queue(nbd->disk->queue);
671 blk_mq_tagset_busy_iter(&nbd->tag_set, nbd_clear_req, NULL);
672 blk_mq_unquiesce_queue(nbd->disk->queue);
673 dev_dbg(disk_to_dev(nbd->disk), "queue cleared\n");
674 }
675
676 static int find_fallback(struct nbd_device *nbd, int index)
677 {
678 struct nbd_config *config = nbd->config;
679 int new_index = -1;
680 struct nbd_sock *nsock = config->socks[index];
681 int fallback = nsock->fallback_index;
682
683 if (test_bit(NBD_DISCONNECTED, &config->runtime_flags))
684 return new_index;
685
686 if (config->num_connections <= 1) {
687 dev_err_ratelimited(disk_to_dev(nbd->disk),
688 "Attempted send on invalid socket\n");
689 return new_index;
690 }
691
692 if (fallback >= 0 && fallback < config->num_connections &&
693 !config->socks[fallback]->dead)
694 return fallback;
695
696 if (nsock->fallback_index < 0 ||
697 nsock->fallback_index >= config->num_connections ||
698 config->socks[nsock->fallback_index]->dead) {
699 int i;
700 for (i = 0; i < config->num_connections; i++) {
701 if (i == index)
702 continue;
703 if (!config->socks[i]->dead) {
704 new_index = i;
705 break;
706 }
707 }
708 nsock->fallback_index = new_index;
709 if (new_index < 0) {
710 dev_err_ratelimited(disk_to_dev(nbd->disk),
711 "Dead connection, failed to find a fallback\n");
712 return new_index;
713 }
714 }
715 new_index = nsock->fallback_index;
716 return new_index;
717 }
718
719 static int wait_for_reconnect(struct nbd_device *nbd)
720 {
721 struct nbd_config *config = nbd->config;
722 if (!config->dead_conn_timeout)
723 return 0;
724 if (test_bit(NBD_DISCONNECTED, &config->runtime_flags))
725 return 0;
726 wait_event_interruptible_timeout(config->conn_wait,
727 atomic_read(&config->live_connections),
728 config->dead_conn_timeout);
729 return atomic_read(&config->live_connections);
730 }
731
732 static int nbd_handle_cmd(struct nbd_cmd *cmd, int index)
733 {
734 struct request *req = blk_mq_rq_from_pdu(cmd);
735 struct nbd_device *nbd = cmd->nbd;
736 struct nbd_config *config;
737 struct nbd_sock *nsock;
738 int ret;
739
740 if (!refcount_inc_not_zero(&nbd->config_refs)) {
741 dev_err_ratelimited(disk_to_dev(nbd->disk),
742 "Socks array is empty\n");
743 return -EINVAL;
744 }
745 config = nbd->config;
746
747 if (index >= config->num_connections) {
748 dev_err_ratelimited(disk_to_dev(nbd->disk),
749 "Attempted send on invalid socket\n");
750 nbd_config_put(nbd);
751 return -EINVAL;
752 }
753 cmd->status = BLK_STS_OK;
754 again:
755 nsock = config->socks[index];
756 mutex_lock(&nsock->tx_lock);
757 if (nsock->dead) {
758 int old_index = index;
759 index = find_fallback(nbd, index);
760 mutex_unlock(&nsock->tx_lock);
761 if (index < 0) {
762 if (wait_for_reconnect(nbd)) {
763 index = old_index;
764 goto again;
765 }
766 /* All the sockets should already be down at this point,
767 * we just want to make sure that DISCONNECTED is set so
768 * any requests that come in that were queue'ed waiting
769 * for the reconnect timer don't trigger the timer again
770 * and instead just error out.
771 */
772 sock_shutdown(nbd);
773 nbd_config_put(nbd);
774 return -EIO;
775 }
776 goto again;
777 }
778
779 /* Handle the case that we have a pending request that was partially
780 * transmitted that _has_ to be serviced first. We need to call requeue
781 * here so that it gets put _after_ the request that is already on the
782 * dispatch list.
783 */
784 if (unlikely(nsock->pending && nsock->pending != req)) {
785 blk_mq_requeue_request(req, true);
786 ret = 0;
787 goto out;
788 }
789 /*
790 * Some failures are related to the link going down, so anything that
791 * returns EAGAIN can be retried on a different socket.
792 */
793 ret = nbd_send_cmd(nbd, cmd, index);
794 if (ret == -EAGAIN) {
795 dev_err_ratelimited(disk_to_dev(nbd->disk),
796 "Request send failed trying another connection\n");
797 nbd_mark_nsock_dead(nbd, nsock, 1);
798 mutex_unlock(&nsock->tx_lock);
799 goto again;
800 }
801 out:
802 mutex_unlock(&nsock->tx_lock);
803 nbd_config_put(nbd);
804 return ret;
805 }
806
807 static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
808 const struct blk_mq_queue_data *bd)
809 {
810 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
811 int ret;
812
813 /*
814 * Since we look at the bio's to send the request over the network we
815 * need to make sure the completion work doesn't mark this request done
816 * before we are done doing our send. This keeps us from dereferencing
817 * freed data if we have particularly fast completions (ie we get the
818 * completion before we exit sock_xmit on the last bvec) or in the case
819 * that the server is misbehaving (or there was an error) before we're
820 * done sending everything over the wire.
821 */
822 init_completion(&cmd->send_complete);
823 blk_mq_start_request(bd->rq);
824
825 /* We can be called directly from the user space process, which means we
826 * could possibly have signals pending so our sendmsg will fail. In
827 * this case we need to return that we are busy, otherwise error out as
828 * appropriate.
829 */
830 ret = nbd_handle_cmd(cmd, hctx->queue_num);
831 complete(&cmd->send_complete);
832
833 return ret < 0 ? BLK_STS_IOERR : BLK_STS_OK;
834 }
835
836 static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
837 bool netlink)
838 {
839 struct nbd_config *config = nbd->config;
840 struct socket *sock;
841 struct nbd_sock **socks;
842 struct nbd_sock *nsock;
843 int err;
844
845 sock = sockfd_lookup(arg, &err);
846 if (!sock)
847 return err;
848
849 if (!netlink && !nbd->task_setup &&
850 !test_bit(NBD_BOUND, &config->runtime_flags))
851 nbd->task_setup = current;
852
853 if (!netlink &&
854 (nbd->task_setup != current ||
855 test_bit(NBD_BOUND, &config->runtime_flags))) {
856 dev_err(disk_to_dev(nbd->disk),
857 "Device being setup by another task");
858 sockfd_put(sock);
859 return -EBUSY;
860 }
861
862 socks = krealloc(config->socks, (config->num_connections + 1) *
863 sizeof(struct nbd_sock *), GFP_KERNEL);
864 if (!socks) {
865 sockfd_put(sock);
866 return -ENOMEM;
867 }
868 nsock = kzalloc(sizeof(struct nbd_sock), GFP_KERNEL);
869 if (!nsock) {
870 sockfd_put(sock);
871 return -ENOMEM;
872 }
873
874 config->socks = socks;
875
876 nsock->fallback_index = -1;
877 nsock->dead = false;
878 mutex_init(&nsock->tx_lock);
879 nsock->sock = sock;
880 nsock->pending = NULL;
881 nsock->sent = 0;
882 nsock->cookie = 0;
883 socks[config->num_connections++] = nsock;
884 atomic_inc(&config->live_connections);
885
886 return 0;
887 }
888
889 static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg)
890 {
891 struct nbd_config *config = nbd->config;
892 struct socket *sock, *old;
893 struct recv_thread_args *args;
894 int i;
895 int err;
896
897 sock = sockfd_lookup(arg, &err);
898 if (!sock)
899 return err;
900
901 args = kzalloc(sizeof(*args), GFP_KERNEL);
902 if (!args) {
903 sockfd_put(sock);
904 return -ENOMEM;
905 }
906
907 for (i = 0; i < config->num_connections; i++) {
908 struct nbd_sock *nsock = config->socks[i];
909
910 if (!nsock->dead)
911 continue;
912
913 mutex_lock(&nsock->tx_lock);
914 if (!nsock->dead) {
915 mutex_unlock(&nsock->tx_lock);
916 continue;
917 }
918 sk_set_memalloc(sock->sk);
919 if (nbd->tag_set.timeout)
920 sock->sk->sk_sndtimeo = nbd->tag_set.timeout;
921 atomic_inc(&config->recv_threads);
922 refcount_inc(&nbd->config_refs);
923 old = nsock->sock;
924 nsock->fallback_index = -1;
925 nsock->sock = sock;
926 nsock->dead = false;
927 INIT_WORK(&args->work, recv_work);
928 args->index = i;
929 args->nbd = nbd;
930 nsock->cookie++;
931 mutex_unlock(&nsock->tx_lock);
932 sockfd_put(old);
933
934 clear_bit(NBD_DISCONNECTED, &config->runtime_flags);
935
936 /* We take the tx_mutex in an error path in the recv_work, so we
937 * need to queue_work outside of the tx_mutex.
938 */
939 queue_work(recv_workqueue, &args->work);
940
941 atomic_inc(&config->live_connections);
942 wake_up(&config->conn_wait);
943 return 0;
944 }
945 sockfd_put(sock);
946 kfree(args);
947 return -ENOSPC;
948 }
949
950 static void nbd_bdev_reset(struct block_device *bdev)
951 {
952 if (bdev->bd_openers > 1)
953 return;
954 bd_set_size(bdev, 0);
955 if (max_part > 0) {
956 blkdev_reread_part(bdev);
957 bdev->bd_invalidated = 1;
958 }
959 }
960
961 static void nbd_parse_flags(struct nbd_device *nbd)
962 {
963 struct nbd_config *config = nbd->config;
964 if (config->flags & NBD_FLAG_READ_ONLY)
965 set_disk_ro(nbd->disk, true);
966 else
967 set_disk_ro(nbd->disk, false);
968 if (config->flags & NBD_FLAG_SEND_TRIM)
969 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
970 if (config->flags & NBD_FLAG_SEND_FLUSH) {
971 if (config->flags & NBD_FLAG_SEND_FUA)
972 blk_queue_write_cache(nbd->disk->queue, true, true);
973 else
974 blk_queue_write_cache(nbd->disk->queue, true, false);
975 }
976 else
977 blk_queue_write_cache(nbd->disk->queue, false, false);
978 }
979
980 static void send_disconnects(struct nbd_device *nbd)
981 {
982 struct nbd_config *config = nbd->config;
983 struct nbd_request request = {
984 .magic = htonl(NBD_REQUEST_MAGIC),
985 .type = htonl(NBD_CMD_DISC),
986 };
987 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
988 struct iov_iter from;
989 int i, ret;
990
991 for (i = 0; i < config->num_connections; i++) {
992 struct nbd_sock *nsock = config->socks[i];
993
994 iov_iter_kvec(&from, WRITE | ITER_KVEC, &iov, 1, sizeof(request));
995 mutex_lock(&nsock->tx_lock);
996 ret = sock_xmit(nbd, i, 1, &from, 0, NULL);
997 if (ret <= 0)
998 dev_err(disk_to_dev(nbd->disk),
999 "Send disconnect failed %d\n", ret);
1000 mutex_unlock(&nsock->tx_lock);
1001 }
1002 }
1003
1004 static int nbd_disconnect(struct nbd_device *nbd)
1005 {
1006 struct nbd_config *config = nbd->config;
1007
1008 dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
1009 set_bit(NBD_DISCONNECT_REQUESTED, &config->runtime_flags);
1010 send_disconnects(nbd);
1011 return 0;
1012 }
1013
1014 static void nbd_clear_sock(struct nbd_device *nbd)
1015 {
1016 sock_shutdown(nbd);
1017 nbd_clear_que(nbd);
1018 nbd->task_setup = NULL;
1019 }
1020
1021 static void nbd_config_put(struct nbd_device *nbd)
1022 {
1023 if (refcount_dec_and_mutex_lock(&nbd->config_refs,
1024 &nbd->config_lock)) {
1025 struct nbd_config *config = nbd->config;
1026 nbd_dev_dbg_close(nbd);
1027 nbd_size_clear(nbd);
1028 if (test_and_clear_bit(NBD_HAS_PID_FILE,
1029 &config->runtime_flags))
1030 device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
1031 nbd->task_recv = NULL;
1032 nbd_clear_sock(nbd);
1033 if (config->num_connections) {
1034 int i;
1035 for (i = 0; i < config->num_connections; i++) {
1036 sockfd_put(config->socks[i]->sock);
1037 kfree(config->socks[i]);
1038 }
1039 kfree(config->socks);
1040 }
1041 kfree(nbd->config);
1042 nbd->config = NULL;
1043
1044 nbd->tag_set.timeout = 0;
1045 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
1046
1047 mutex_unlock(&nbd->config_lock);
1048 nbd_put(nbd);
1049 module_put(THIS_MODULE);
1050 }
1051 }
1052
1053 static int nbd_start_device(struct nbd_device *nbd)
1054 {
1055 struct nbd_config *config = nbd->config;
1056 int num_connections = config->num_connections;
1057 int error = 0, i;
1058
1059 if (nbd->task_recv)
1060 return -EBUSY;
1061 if (!config->socks)
1062 return -EINVAL;
1063 if (num_connections > 1 &&
1064 !(config->flags & NBD_FLAG_CAN_MULTI_CONN)) {
1065 dev_err(disk_to_dev(nbd->disk), "server does not support multiple connections per device.\n");
1066 return -EINVAL;
1067 }
1068
1069 blk_mq_update_nr_hw_queues(&nbd->tag_set, config->num_connections);
1070 nbd->task_recv = current;
1071
1072 nbd_parse_flags(nbd);
1073
1074 error = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
1075 if (error) {
1076 dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n");
1077 return error;
1078 }
1079 set_bit(NBD_HAS_PID_FILE, &config->runtime_flags);
1080
1081 nbd_dev_dbg_init(nbd);
1082 for (i = 0; i < num_connections; i++) {
1083 struct recv_thread_args *args;
1084
1085 args = kzalloc(sizeof(*args), GFP_KERNEL);
1086 if (!args) {
1087 sock_shutdown(nbd);
1088 return -ENOMEM;
1089 }
1090 sk_set_memalloc(config->socks[i]->sock->sk);
1091 if (nbd->tag_set.timeout)
1092 config->socks[i]->sock->sk->sk_sndtimeo =
1093 nbd->tag_set.timeout;
1094 atomic_inc(&config->recv_threads);
1095 refcount_inc(&nbd->config_refs);
1096 INIT_WORK(&args->work, recv_work);
1097 args->nbd = nbd;
1098 args->index = i;
1099 queue_work(recv_workqueue, &args->work);
1100 }
1101 nbd_size_update(nbd);
1102 return error;
1103 }
1104
1105 static int nbd_start_device_ioctl(struct nbd_device *nbd, struct block_device *bdev)
1106 {
1107 struct nbd_config *config = nbd->config;
1108 int ret;
1109
1110 ret = nbd_start_device(nbd);
1111 if (ret)
1112 return ret;
1113
1114 bd_set_size(bdev, config->bytesize);
1115 if (max_part)
1116 bdev->bd_invalidated = 1;
1117 mutex_unlock(&nbd->config_lock);
1118 ret = wait_event_interruptible(config->recv_wq,
1119 atomic_read(&config->recv_threads) == 0);
1120 if (ret)
1121 sock_shutdown(nbd);
1122 mutex_lock(&nbd->config_lock);
1123 bd_set_size(bdev, 0);
1124 /* user requested, ignore socket errors */
1125 if (test_bit(NBD_DISCONNECT_REQUESTED, &config->runtime_flags))
1126 ret = 0;
1127 if (test_bit(NBD_TIMEDOUT, &config->runtime_flags))
1128 ret = -ETIMEDOUT;
1129 return ret;
1130 }
1131
1132 static void nbd_clear_sock_ioctl(struct nbd_device *nbd,
1133 struct block_device *bdev)
1134 {
1135 sock_shutdown(nbd);
1136 kill_bdev(bdev);
1137 nbd_bdev_reset(bdev);
1138 if (test_and_clear_bit(NBD_HAS_CONFIG_REF,
1139 &nbd->config->runtime_flags))
1140 nbd_config_put(nbd);
1141 }
1142
1143 /* Must be called with config_lock held */
1144 static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
1145 unsigned int cmd, unsigned long arg)
1146 {
1147 struct nbd_config *config = nbd->config;
1148
1149 switch (cmd) {
1150 case NBD_DISCONNECT:
1151 return nbd_disconnect(nbd);
1152 case NBD_CLEAR_SOCK:
1153 nbd_clear_sock_ioctl(nbd, bdev);
1154 return 0;
1155 case NBD_SET_SOCK:
1156 return nbd_add_socket(nbd, arg, false);
1157 case NBD_SET_BLKSIZE:
1158 nbd_size_set(nbd, arg,
1159 div_s64(config->bytesize, arg));
1160 return 0;
1161 case NBD_SET_SIZE:
1162 nbd_size_set(nbd, config->blksize,
1163 div_s64(arg, config->blksize));
1164 return 0;
1165 case NBD_SET_SIZE_BLOCKS:
1166 nbd_size_set(nbd, config->blksize, arg);
1167 return 0;
1168 case NBD_SET_TIMEOUT:
1169 if (arg) {
1170 nbd->tag_set.timeout = arg * HZ;
1171 blk_queue_rq_timeout(nbd->disk->queue, arg * HZ);
1172 }
1173 return 0;
1174
1175 case NBD_SET_FLAGS:
1176 config->flags = arg;
1177 return 0;
1178 case NBD_DO_IT:
1179 return nbd_start_device_ioctl(nbd, bdev);
1180 case NBD_CLEAR_QUE:
1181 /*
1182 * This is for compatibility only. The queue is always cleared
1183 * by NBD_DO_IT or NBD_CLEAR_SOCK.
1184 */
1185 return 0;
1186 case NBD_PRINT_DEBUG:
1187 /*
1188 * For compatibility only, we no longer keep a list of
1189 * outstanding requests.
1190 */
1191 return 0;
1192 }
1193 return -ENOTTY;
1194 }
1195
1196 static int nbd_ioctl(struct block_device *bdev, fmode_t mode,
1197 unsigned int cmd, unsigned long arg)
1198 {
1199 struct nbd_device *nbd = bdev->bd_disk->private_data;
1200 struct nbd_config *config = nbd->config;
1201 int error = -EINVAL;
1202
1203 if (!capable(CAP_SYS_ADMIN))
1204 return -EPERM;
1205
1206 mutex_lock(&nbd->config_lock);
1207
1208 /* Don't allow ioctl operations on a nbd device that was created with
1209 * netlink, unless it's DISCONNECT or CLEAR_SOCK, which are fine.
1210 */
1211 if (!test_bit(NBD_BOUND, &config->runtime_flags) ||
1212 (cmd == NBD_DISCONNECT || cmd == NBD_CLEAR_SOCK))
1213 error = __nbd_ioctl(bdev, nbd, cmd, arg);
1214 else
1215 dev_err(nbd_to_dev(nbd), "Cannot use ioctl interface on a netlink controlled device.\n");
1216 mutex_unlock(&nbd->config_lock);
1217 return error;
1218 }
1219
1220 static struct nbd_config *nbd_alloc_config(void)
1221 {
1222 struct nbd_config *config;
1223
1224 config = kzalloc(sizeof(struct nbd_config), GFP_NOFS);
1225 if (!config)
1226 return NULL;
1227 atomic_set(&config->recv_threads, 0);
1228 init_waitqueue_head(&config->recv_wq);
1229 init_waitqueue_head(&config->conn_wait);
1230 config->blksize = 1024;
1231 atomic_set(&config->live_connections, 0);
1232 try_module_get(THIS_MODULE);
1233 return config;
1234 }
1235
1236 static int nbd_open(struct block_device *bdev, fmode_t mode)
1237 {
1238 struct nbd_device *nbd;
1239 int ret = 0;
1240
1241 mutex_lock(&nbd_index_mutex);
1242 nbd = bdev->bd_disk->private_data;
1243 if (!nbd) {
1244 ret = -ENXIO;
1245 goto out;
1246 }
1247 if (!refcount_inc_not_zero(&nbd->refs)) {
1248 ret = -ENXIO;
1249 goto out;
1250 }
1251 if (!refcount_inc_not_zero(&nbd->config_refs)) {
1252 struct nbd_config *config;
1253
1254 mutex_lock(&nbd->config_lock);
1255 if (refcount_inc_not_zero(&nbd->config_refs)) {
1256 mutex_unlock(&nbd->config_lock);
1257 goto out;
1258 }
1259 config = nbd->config = nbd_alloc_config();
1260 if (!config) {
1261 ret = -ENOMEM;
1262 mutex_unlock(&nbd->config_lock);
1263 goto out;
1264 }
1265 refcount_set(&nbd->config_refs, 1);
1266 refcount_inc(&nbd->refs);
1267 mutex_unlock(&nbd->config_lock);
1268 }
1269 out:
1270 mutex_unlock(&nbd_index_mutex);
1271 return ret;
1272 }
1273
1274 static void nbd_release(struct gendisk *disk, fmode_t mode)
1275 {
1276 struct nbd_device *nbd = disk->private_data;
1277 nbd_config_put(nbd);
1278 nbd_put(nbd);
1279 }
1280
1281 static const struct block_device_operations nbd_fops =
1282 {
1283 .owner = THIS_MODULE,
1284 .open = nbd_open,
1285 .release = nbd_release,
1286 .ioctl = nbd_ioctl,
1287 .compat_ioctl = nbd_ioctl,
1288 };
1289
1290 #if IS_ENABLED(CONFIG_DEBUG_FS)
1291
1292 static int nbd_dbg_tasks_show(struct seq_file *s, void *unused)
1293 {
1294 struct nbd_device *nbd = s->private;
1295
1296 if (nbd->task_recv)
1297 seq_printf(s, "recv: %d\n", task_pid_nr(nbd->task_recv));
1298
1299 return 0;
1300 }
1301
1302 static int nbd_dbg_tasks_open(struct inode *inode, struct file *file)
1303 {
1304 return single_open(file, nbd_dbg_tasks_show, inode->i_private);
1305 }
1306
1307 static const struct file_operations nbd_dbg_tasks_ops = {
1308 .open = nbd_dbg_tasks_open,
1309 .read = seq_read,
1310 .llseek = seq_lseek,
1311 .release = single_release,
1312 };
1313
1314 static int nbd_dbg_flags_show(struct seq_file *s, void *unused)
1315 {
1316 struct nbd_device *nbd = s->private;
1317 u32 flags = nbd->config->flags;
1318
1319 seq_printf(s, "Hex: 0x%08x\n\n", flags);
1320
1321 seq_puts(s, "Known flags:\n");
1322
1323 if (flags & NBD_FLAG_HAS_FLAGS)
1324 seq_puts(s, "NBD_FLAG_HAS_FLAGS\n");
1325 if (flags & NBD_FLAG_READ_ONLY)
1326 seq_puts(s, "NBD_FLAG_READ_ONLY\n");
1327 if (flags & NBD_FLAG_SEND_FLUSH)
1328 seq_puts(s, "NBD_FLAG_SEND_FLUSH\n");
1329 if (flags & NBD_FLAG_SEND_FUA)
1330 seq_puts(s, "NBD_FLAG_SEND_FUA\n");
1331 if (flags & NBD_FLAG_SEND_TRIM)
1332 seq_puts(s, "NBD_FLAG_SEND_TRIM\n");
1333
1334 return 0;
1335 }
1336
1337 static int nbd_dbg_flags_open(struct inode *inode, struct file *file)
1338 {
1339 return single_open(file, nbd_dbg_flags_show, inode->i_private);
1340 }
1341
1342 static const struct file_operations nbd_dbg_flags_ops = {
1343 .open = nbd_dbg_flags_open,
1344 .read = seq_read,
1345 .llseek = seq_lseek,
1346 .release = single_release,
1347 };
1348
1349 static int nbd_dev_dbg_init(struct nbd_device *nbd)
1350 {
1351 struct dentry *dir;
1352 struct nbd_config *config = nbd->config;
1353
1354 if (!nbd_dbg_dir)
1355 return -EIO;
1356
1357 dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir);
1358 if (!dir) {
1359 dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s'\n",
1360 nbd_name(nbd));
1361 return -EIO;
1362 }
1363 config->dbg_dir = dir;
1364
1365 debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_ops);
1366 debugfs_create_u64("size_bytes", 0444, dir, &config->bytesize);
1367 debugfs_create_u32("timeout", 0444, dir, &nbd->tag_set.timeout);
1368 debugfs_create_u64("blocksize", 0444, dir, &config->blksize);
1369 debugfs_create_file("flags", 0444, dir, nbd, &nbd_dbg_flags_ops);
1370
1371 return 0;
1372 }
1373
1374 static void nbd_dev_dbg_close(struct nbd_device *nbd)
1375 {
1376 debugfs_remove_recursive(nbd->config->dbg_dir);
1377 }
1378
1379 static int nbd_dbg_init(void)
1380 {
1381 struct dentry *dbg_dir;
1382
1383 dbg_dir = debugfs_create_dir("nbd", NULL);
1384 if (!dbg_dir)
1385 return -EIO;
1386
1387 nbd_dbg_dir = dbg_dir;
1388
1389 return 0;
1390 }
1391
1392 static void nbd_dbg_close(void)
1393 {
1394 debugfs_remove_recursive(nbd_dbg_dir);
1395 }
1396
1397 #else /* IS_ENABLED(CONFIG_DEBUG_FS) */
1398
1399 static int nbd_dev_dbg_init(struct nbd_device *nbd)
1400 {
1401 return 0;
1402 }
1403
1404 static void nbd_dev_dbg_close(struct nbd_device *nbd)
1405 {
1406 }
1407
1408 static int nbd_dbg_init(void)
1409 {
1410 return 0;
1411 }
1412
1413 static void nbd_dbg_close(void)
1414 {
1415 }
1416
1417 #endif
1418
1419 static int nbd_init_request(struct blk_mq_tag_set *set, struct request *rq,
1420 unsigned int hctx_idx, unsigned int numa_node)
1421 {
1422 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq);
1423 cmd->nbd = set->driver_data;
1424 return 0;
1425 }
1426
1427 static const struct blk_mq_ops nbd_mq_ops = {
1428 .queue_rq = nbd_queue_rq,
1429 .complete = nbd_complete_rq,
1430 .init_request = nbd_init_request,
1431 .timeout = nbd_xmit_timeout,
1432 };
1433
1434 static int nbd_dev_add(int index)
1435 {
1436 struct nbd_device *nbd;
1437 struct gendisk *disk;
1438 struct request_queue *q;
1439 int err = -ENOMEM;
1440
1441 nbd = kzalloc(sizeof(struct nbd_device), GFP_KERNEL);
1442 if (!nbd)
1443 goto out;
1444
1445 disk = alloc_disk(1 << part_shift);
1446 if (!disk)
1447 goto out_free_nbd;
1448
1449 if (index >= 0) {
1450 err = idr_alloc(&nbd_index_idr, nbd, index, index + 1,
1451 GFP_KERNEL);
1452 if (err == -ENOSPC)
1453 err = -EEXIST;
1454 } else {
1455 err = idr_alloc(&nbd_index_idr, nbd, 0, 0, GFP_KERNEL);
1456 if (err >= 0)
1457 index = err;
1458 }
1459 if (err < 0)
1460 goto out_free_disk;
1461
1462 nbd->index = index;
1463 nbd->disk = disk;
1464 nbd->tag_set.ops = &nbd_mq_ops;
1465 nbd->tag_set.nr_hw_queues = 1;
1466 nbd->tag_set.queue_depth = 128;
1467 nbd->tag_set.numa_node = NUMA_NO_NODE;
1468 nbd->tag_set.cmd_size = sizeof(struct nbd_cmd);
1469 nbd->tag_set.flags = BLK_MQ_F_SHOULD_MERGE |
1470 BLK_MQ_F_SG_MERGE | BLK_MQ_F_BLOCKING;
1471 nbd->tag_set.driver_data = nbd;
1472
1473 err = blk_mq_alloc_tag_set(&nbd->tag_set);
1474 if (err)
1475 goto out_free_idr;
1476
1477 q = blk_mq_init_queue(&nbd->tag_set);
1478 if (IS_ERR(q)) {
1479 err = PTR_ERR(q);
1480 goto out_free_tags;
1481 }
1482 disk->queue = q;
1483
1484 /*
1485 * Tell the block layer that we are not a rotational device
1486 */
1487 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue);
1488 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, disk->queue);
1489 disk->queue->limits.discard_granularity = 512;
1490 blk_queue_max_discard_sectors(disk->queue, UINT_MAX);
1491 blk_queue_max_segment_size(disk->queue, UINT_MAX);
1492 blk_queue_max_segments(disk->queue, USHRT_MAX);
1493 blk_queue_max_hw_sectors(disk->queue, 65536);
1494 disk->queue->limits.max_sectors = 256;
1495
1496 mutex_init(&nbd->config_lock);
1497 refcount_set(&nbd->config_refs, 0);
1498 refcount_set(&nbd->refs, 1);
1499 INIT_LIST_HEAD(&nbd->list);
1500 disk->major = NBD_MAJOR;
1501 disk->first_minor = index << part_shift;
1502 disk->fops = &nbd_fops;
1503 disk->private_data = nbd;
1504 sprintf(disk->disk_name, "nbd%d", index);
1505 add_disk(disk);
1506 nbd_total_devices++;
1507 return index;
1508
1509 out_free_tags:
1510 blk_mq_free_tag_set(&nbd->tag_set);
1511 out_free_idr:
1512 idr_remove(&nbd_index_idr, index);
1513 out_free_disk:
1514 put_disk(disk);
1515 out_free_nbd:
1516 kfree(nbd);
1517 out:
1518 return err;
1519 }
1520
1521 static int find_free_cb(int id, void *ptr, void *data)
1522 {
1523 struct nbd_device *nbd = ptr;
1524 struct nbd_device **found = data;
1525
1526 if (!refcount_read(&nbd->config_refs)) {
1527 *found = nbd;
1528 return 1;
1529 }
1530 return 0;
1531 }
1532
1533 /* Netlink interface. */
1534 static struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = {
1535 [NBD_ATTR_INDEX] = { .type = NLA_U32 },
1536 [NBD_ATTR_SIZE_BYTES] = { .type = NLA_U64 },
1537 [NBD_ATTR_BLOCK_SIZE_BYTES] = { .type = NLA_U64 },
1538 [NBD_ATTR_TIMEOUT] = { .type = NLA_U64 },
1539 [NBD_ATTR_SERVER_FLAGS] = { .type = NLA_U64 },
1540 [NBD_ATTR_CLIENT_FLAGS] = { .type = NLA_U64 },
1541 [NBD_ATTR_SOCKETS] = { .type = NLA_NESTED},
1542 [NBD_ATTR_DEAD_CONN_TIMEOUT] = { .type = NLA_U64 },
1543 [NBD_ATTR_DEVICE_LIST] = { .type = NLA_NESTED},
1544 };
1545
1546 static struct nla_policy nbd_sock_policy[NBD_SOCK_MAX + 1] = {
1547 [NBD_SOCK_FD] = { .type = NLA_U32 },
1548 };
1549
1550 /* We don't use this right now since we don't parse the incoming list, but we
1551 * still want it here so userspace knows what to expect.
1552 */
1553 static struct nla_policy __attribute__((unused))
1554 nbd_device_policy[NBD_DEVICE_ATTR_MAX + 1] = {
1555 [NBD_DEVICE_INDEX] = { .type = NLA_U32 },
1556 [NBD_DEVICE_CONNECTED] = { .type = NLA_U8 },
1557 };
1558
1559 static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
1560 {
1561 struct nbd_device *nbd = NULL;
1562 struct nbd_config *config;
1563 int index = -1;
1564 int ret;
1565 bool put_dev = false;
1566
1567 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1568 return -EPERM;
1569
1570 if (info->attrs[NBD_ATTR_INDEX])
1571 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1572 if (!info->attrs[NBD_ATTR_SOCKETS]) {
1573 printk(KERN_ERR "nbd: must specify at least one socket\n");
1574 return -EINVAL;
1575 }
1576 if (!info->attrs[NBD_ATTR_SIZE_BYTES]) {
1577 printk(KERN_ERR "nbd: must specify a size in bytes for the device\n");
1578 return -EINVAL;
1579 }
1580 again:
1581 mutex_lock(&nbd_index_mutex);
1582 if (index == -1) {
1583 ret = idr_for_each(&nbd_index_idr, &find_free_cb, &nbd);
1584 if (ret == 0) {
1585 int new_index;
1586 new_index = nbd_dev_add(-1);
1587 if (new_index < 0) {
1588 mutex_unlock(&nbd_index_mutex);
1589 printk(KERN_ERR "nbd: failed to add new device\n");
1590 return ret;
1591 }
1592 nbd = idr_find(&nbd_index_idr, new_index);
1593 }
1594 } else {
1595 nbd = idr_find(&nbd_index_idr, index);
1596 }
1597 if (!nbd) {
1598 printk(KERN_ERR "nbd: couldn't find device at index %d\n",
1599 index);
1600 mutex_unlock(&nbd_index_mutex);
1601 return -EINVAL;
1602 }
1603 if (!refcount_inc_not_zero(&nbd->refs)) {
1604 mutex_unlock(&nbd_index_mutex);
1605 if (index == -1)
1606 goto again;
1607 printk(KERN_ERR "nbd: device at index %d is going down\n",
1608 index);
1609 return -EINVAL;
1610 }
1611 mutex_unlock(&nbd_index_mutex);
1612
1613 mutex_lock(&nbd->config_lock);
1614 if (refcount_read(&nbd->config_refs)) {
1615 mutex_unlock(&nbd->config_lock);
1616 nbd_put(nbd);
1617 if (index == -1)
1618 goto again;
1619 printk(KERN_ERR "nbd: nbd%d already in use\n", index);
1620 return -EBUSY;
1621 }
1622 if (WARN_ON(nbd->config)) {
1623 mutex_unlock(&nbd->config_lock);
1624 nbd_put(nbd);
1625 return -EINVAL;
1626 }
1627 config = nbd->config = nbd_alloc_config();
1628 if (!nbd->config) {
1629 mutex_unlock(&nbd->config_lock);
1630 nbd_put(nbd);
1631 printk(KERN_ERR "nbd: couldn't allocate config\n");
1632 return -ENOMEM;
1633 }
1634 refcount_set(&nbd->config_refs, 1);
1635 set_bit(NBD_BOUND, &config->runtime_flags);
1636
1637 if (info->attrs[NBD_ATTR_SIZE_BYTES]) {
1638 u64 bytes = nla_get_u64(info->attrs[NBD_ATTR_SIZE_BYTES]);
1639 nbd_size_set(nbd, config->blksize,
1640 div64_u64(bytes, config->blksize));
1641 }
1642 if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]) {
1643 u64 bsize =
1644 nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]);
1645 nbd_size_set(nbd, bsize, div64_u64(config->bytesize, bsize));
1646 }
1647 if (info->attrs[NBD_ATTR_TIMEOUT]) {
1648 u64 timeout = nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]);
1649 nbd->tag_set.timeout = timeout * HZ;
1650 blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ);
1651 }
1652 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
1653 config->dead_conn_timeout =
1654 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
1655 config->dead_conn_timeout *= HZ;
1656 }
1657 if (info->attrs[NBD_ATTR_SERVER_FLAGS])
1658 config->flags =
1659 nla_get_u64(info->attrs[NBD_ATTR_SERVER_FLAGS]);
1660 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
1661 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
1662 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
1663 set_bit(NBD_DESTROY_ON_DISCONNECT,
1664 &config->runtime_flags);
1665 put_dev = true;
1666 }
1667 }
1668
1669 if (info->attrs[NBD_ATTR_SOCKETS]) {
1670 struct nlattr *attr;
1671 int rem, fd;
1672
1673 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
1674 rem) {
1675 struct nlattr *socks[NBD_SOCK_MAX+1];
1676
1677 if (nla_type(attr) != NBD_SOCK_ITEM) {
1678 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");
1679 ret = -EINVAL;
1680 goto out;
1681 }
1682 ret = nla_parse_nested(socks, NBD_SOCK_MAX, attr,
1683 nbd_sock_policy, info->extack);
1684 if (ret != 0) {
1685 printk(KERN_ERR "nbd: error processing sock list\n");
1686 ret = -EINVAL;
1687 goto out;
1688 }
1689 if (!socks[NBD_SOCK_FD])
1690 continue;
1691 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
1692 ret = nbd_add_socket(nbd, fd, true);
1693 if (ret)
1694 goto out;
1695 }
1696 }
1697 ret = nbd_start_device(nbd);
1698 out:
1699 mutex_unlock(&nbd->config_lock);
1700 if (!ret) {
1701 set_bit(NBD_HAS_CONFIG_REF, &config->runtime_flags);
1702 refcount_inc(&nbd->config_refs);
1703 nbd_connect_reply(info, nbd->index);
1704 }
1705 nbd_config_put(nbd);
1706 if (put_dev)
1707 nbd_put(nbd);
1708 return ret;
1709 }
1710
1711 static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info)
1712 {
1713 struct nbd_device *nbd;
1714 int index;
1715
1716 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1717 return -EPERM;
1718
1719 if (!info->attrs[NBD_ATTR_INDEX]) {
1720 printk(KERN_ERR "nbd: must specify an index to disconnect\n");
1721 return -EINVAL;
1722 }
1723 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1724 mutex_lock(&nbd_index_mutex);
1725 nbd = idr_find(&nbd_index_idr, index);
1726 if (!nbd) {
1727 mutex_unlock(&nbd_index_mutex);
1728 printk(KERN_ERR "nbd: couldn't find device at index %d\n",
1729 index);
1730 return -EINVAL;
1731 }
1732 if (!refcount_inc_not_zero(&nbd->refs)) {
1733 mutex_unlock(&nbd_index_mutex);
1734 printk(KERN_ERR "nbd: device at index %d is going down\n",
1735 index);
1736 return -EINVAL;
1737 }
1738 mutex_unlock(&nbd_index_mutex);
1739 if (!refcount_inc_not_zero(&nbd->config_refs)) {
1740 nbd_put(nbd);
1741 return 0;
1742 }
1743 mutex_lock(&nbd->config_lock);
1744 nbd_disconnect(nbd);
1745 mutex_unlock(&nbd->config_lock);
1746 if (test_and_clear_bit(NBD_HAS_CONFIG_REF,
1747 &nbd->config->runtime_flags))
1748 nbd_config_put(nbd);
1749 nbd_config_put(nbd);
1750 nbd_put(nbd);
1751 return 0;
1752 }
1753
1754 static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info)
1755 {
1756 struct nbd_device *nbd = NULL;
1757 struct nbd_config *config;
1758 int index;
1759 int ret = -EINVAL;
1760 bool put_dev = false;
1761
1762 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1763 return -EPERM;
1764
1765 if (!info->attrs[NBD_ATTR_INDEX]) {
1766 printk(KERN_ERR "nbd: must specify a device to reconfigure\n");
1767 return -EINVAL;
1768 }
1769 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1770 mutex_lock(&nbd_index_mutex);
1771 nbd = idr_find(&nbd_index_idr, index);
1772 if (!nbd) {
1773 mutex_unlock(&nbd_index_mutex);
1774 printk(KERN_ERR "nbd: couldn't find a device at index %d\n",
1775 index);
1776 return -EINVAL;
1777 }
1778 if (!refcount_inc_not_zero(&nbd->refs)) {
1779 mutex_unlock(&nbd_index_mutex);
1780 printk(KERN_ERR "nbd: device at index %d is going down\n",
1781 index);
1782 return -EINVAL;
1783 }
1784 mutex_unlock(&nbd_index_mutex);
1785
1786 if (!refcount_inc_not_zero(&nbd->config_refs)) {
1787 dev_err(nbd_to_dev(nbd),
1788 "not configured, cannot reconfigure\n");
1789 nbd_put(nbd);
1790 return -EINVAL;
1791 }
1792
1793 mutex_lock(&nbd->config_lock);
1794 config = nbd->config;
1795 if (!test_bit(NBD_BOUND, &config->runtime_flags) ||
1796 !nbd->task_recv) {
1797 dev_err(nbd_to_dev(nbd),
1798 "not configured, cannot reconfigure\n");
1799 goto out;
1800 }
1801
1802 if (info->attrs[NBD_ATTR_TIMEOUT]) {
1803 u64 timeout = nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]);
1804 nbd->tag_set.timeout = timeout * HZ;
1805 blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ);
1806 }
1807 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
1808 config->dead_conn_timeout =
1809 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
1810 config->dead_conn_timeout *= HZ;
1811 }
1812 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
1813 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
1814 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
1815 if (!test_and_set_bit(NBD_DESTROY_ON_DISCONNECT,
1816 &config->runtime_flags))
1817 put_dev = true;
1818 } else {
1819 if (test_and_clear_bit(NBD_DESTROY_ON_DISCONNECT,
1820 &config->runtime_flags))
1821 refcount_inc(&nbd->refs);
1822 }
1823 }
1824
1825 if (info->attrs[NBD_ATTR_SOCKETS]) {
1826 struct nlattr *attr;
1827 int rem, fd;
1828
1829 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
1830 rem) {
1831 struct nlattr *socks[NBD_SOCK_MAX+1];
1832
1833 if (nla_type(attr) != NBD_SOCK_ITEM) {
1834 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");
1835 ret = -EINVAL;
1836 goto out;
1837 }
1838 ret = nla_parse_nested(socks, NBD_SOCK_MAX, attr,
1839 nbd_sock_policy, info->extack);
1840 if (ret != 0) {
1841 printk(KERN_ERR "nbd: error processing sock list\n");
1842 ret = -EINVAL;
1843 goto out;
1844 }
1845 if (!socks[NBD_SOCK_FD])
1846 continue;
1847 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
1848 ret = nbd_reconnect_socket(nbd, fd);
1849 if (ret) {
1850 if (ret == -ENOSPC)
1851 ret = 0;
1852 goto out;
1853 }
1854 dev_info(nbd_to_dev(nbd), "reconnected socket\n");
1855 }
1856 }
1857 out:
1858 mutex_unlock(&nbd->config_lock);
1859 nbd_config_put(nbd);
1860 nbd_put(nbd);
1861 if (put_dev)
1862 nbd_put(nbd);
1863 return ret;
1864 }
1865
1866 static const struct genl_ops nbd_connect_genl_ops[] = {
1867 {
1868 .cmd = NBD_CMD_CONNECT,
1869 .policy = nbd_attr_policy,
1870 .doit = nbd_genl_connect,
1871 },
1872 {
1873 .cmd = NBD_CMD_DISCONNECT,
1874 .policy = nbd_attr_policy,
1875 .doit = nbd_genl_disconnect,
1876 },
1877 {
1878 .cmd = NBD_CMD_RECONFIGURE,
1879 .policy = nbd_attr_policy,
1880 .doit = nbd_genl_reconfigure,
1881 },
1882 {
1883 .cmd = NBD_CMD_STATUS,
1884 .policy = nbd_attr_policy,
1885 .doit = nbd_genl_status,
1886 },
1887 };
1888
1889 static const struct genl_multicast_group nbd_mcast_grps[] = {
1890 { .name = NBD_GENL_MCAST_GROUP_NAME, },
1891 };
1892
1893 static struct genl_family nbd_genl_family __ro_after_init = {
1894 .hdrsize = 0,
1895 .name = NBD_GENL_FAMILY_NAME,
1896 .version = NBD_GENL_VERSION,
1897 .module = THIS_MODULE,
1898 .ops = nbd_connect_genl_ops,
1899 .n_ops = ARRAY_SIZE(nbd_connect_genl_ops),
1900 .maxattr = NBD_ATTR_MAX,
1901 .mcgrps = nbd_mcast_grps,
1902 .n_mcgrps = ARRAY_SIZE(nbd_mcast_grps),
1903 };
1904
1905 static int populate_nbd_status(struct nbd_device *nbd, struct sk_buff *reply)
1906 {
1907 struct nlattr *dev_opt;
1908 u8 connected = 0;
1909 int ret;
1910
1911 /* This is a little racey, but for status it's ok. The
1912 * reason we don't take a ref here is because we can't
1913 * take a ref in the index == -1 case as we would need
1914 * to put under the nbd_index_mutex, which could
1915 * deadlock if we are configured to remove ourselves
1916 * once we're disconnected.
1917 */
1918 if (refcount_read(&nbd->config_refs))
1919 connected = 1;
1920 dev_opt = nla_nest_start(reply, NBD_DEVICE_ITEM);
1921 if (!dev_opt)
1922 return -EMSGSIZE;
1923 ret = nla_put_u32(reply, NBD_DEVICE_INDEX, nbd->index);
1924 if (ret)
1925 return -EMSGSIZE;
1926 ret = nla_put_u8(reply, NBD_DEVICE_CONNECTED,
1927 connected);
1928 if (ret)
1929 return -EMSGSIZE;
1930 nla_nest_end(reply, dev_opt);
1931 return 0;
1932 }
1933
1934 static int status_cb(int id, void *ptr, void *data)
1935 {
1936 struct nbd_device *nbd = ptr;
1937 return populate_nbd_status(nbd, (struct sk_buff *)data);
1938 }
1939
1940 static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info)
1941 {
1942 struct nlattr *dev_list;
1943 struct sk_buff *reply;
1944 void *reply_head;
1945 size_t msg_size;
1946 int index = -1;
1947 int ret = -ENOMEM;
1948
1949 if (info->attrs[NBD_ATTR_INDEX])
1950 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1951
1952 mutex_lock(&nbd_index_mutex);
1953
1954 msg_size = nla_total_size(nla_attr_size(sizeof(u32)) +
1955 nla_attr_size(sizeof(u8)));
1956 msg_size *= (index == -1) ? nbd_total_devices : 1;
1957
1958 reply = genlmsg_new(msg_size, GFP_KERNEL);
1959 if (!reply)
1960 goto out;
1961 reply_head = genlmsg_put_reply(reply, info, &nbd_genl_family, 0,
1962 NBD_CMD_STATUS);
1963 if (!reply_head) {
1964 nlmsg_free(reply);
1965 goto out;
1966 }
1967
1968 dev_list = nla_nest_start(reply, NBD_ATTR_DEVICE_LIST);
1969 if (index == -1) {
1970 ret = idr_for_each(&nbd_index_idr, &status_cb, reply);
1971 if (ret) {
1972 nlmsg_free(reply);
1973 goto out;
1974 }
1975 } else {
1976 struct nbd_device *nbd;
1977 nbd = idr_find(&nbd_index_idr, index);
1978 if (nbd) {
1979 ret = populate_nbd_status(nbd, reply);
1980 if (ret) {
1981 nlmsg_free(reply);
1982 goto out;
1983 }
1984 }
1985 }
1986 nla_nest_end(reply, dev_list);
1987 genlmsg_end(reply, reply_head);
1988 genlmsg_reply(reply, info);
1989 ret = 0;
1990 out:
1991 mutex_unlock(&nbd_index_mutex);
1992 return ret;
1993 }
1994
1995 static void nbd_connect_reply(struct genl_info *info, int index)
1996 {
1997 struct sk_buff *skb;
1998 void *msg_head;
1999 int ret;
2000
2001 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2002 if (!skb)
2003 return;
2004 msg_head = genlmsg_put_reply(skb, info, &nbd_genl_family, 0,
2005 NBD_CMD_CONNECT);
2006 if (!msg_head) {
2007 nlmsg_free(skb);
2008 return;
2009 }
2010 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2011 if (ret) {
2012 nlmsg_free(skb);
2013 return;
2014 }
2015 genlmsg_end(skb, msg_head);
2016 genlmsg_reply(skb, info);
2017 }
2018
2019 static void nbd_mcast_index(int index)
2020 {
2021 struct sk_buff *skb;
2022 void *msg_head;
2023 int ret;
2024
2025 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2026 if (!skb)
2027 return;
2028 msg_head = genlmsg_put(skb, 0, 0, &nbd_genl_family, 0,
2029 NBD_CMD_LINK_DEAD);
2030 if (!msg_head) {
2031 nlmsg_free(skb);
2032 return;
2033 }
2034 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2035 if (ret) {
2036 nlmsg_free(skb);
2037 return;
2038 }
2039 genlmsg_end(skb, msg_head);
2040 genlmsg_multicast(&nbd_genl_family, skb, 0, 0, GFP_KERNEL);
2041 }
2042
2043 static void nbd_dead_link_work(struct work_struct *work)
2044 {
2045 struct link_dead_args *args = container_of(work, struct link_dead_args,
2046 work);
2047 nbd_mcast_index(args->index);
2048 kfree(args);
2049 }
2050
2051 static int __init nbd_init(void)
2052 {
2053 int i;
2054
2055 BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
2056
2057 if (max_part < 0) {
2058 printk(KERN_ERR "nbd: max_part must be >= 0\n");
2059 return -EINVAL;
2060 }
2061
2062 part_shift = 0;
2063 if (max_part > 0) {
2064 part_shift = fls(max_part);
2065
2066 /*
2067 * Adjust max_part according to part_shift as it is exported
2068 * to user space so that user can know the max number of
2069 * partition kernel should be able to manage.
2070 *
2071 * Note that -1 is required because partition 0 is reserved
2072 * for the whole disk.
2073 */
2074 max_part = (1UL << part_shift) - 1;
2075 }
2076
2077 if ((1UL << part_shift) > DISK_MAX_PARTS)
2078 return -EINVAL;
2079
2080 if (nbds_max > 1UL << (MINORBITS - part_shift))
2081 return -EINVAL;
2082 recv_workqueue = alloc_workqueue("knbd-recv",
2083 WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
2084 if (!recv_workqueue)
2085 return -ENOMEM;
2086
2087 if (register_blkdev(NBD_MAJOR, "nbd")) {
2088 destroy_workqueue(recv_workqueue);
2089 return -EIO;
2090 }
2091
2092 if (genl_register_family(&nbd_genl_family)) {
2093 unregister_blkdev(NBD_MAJOR, "nbd");
2094 destroy_workqueue(recv_workqueue);
2095 return -EINVAL;
2096 }
2097 nbd_dbg_init();
2098
2099 mutex_lock(&nbd_index_mutex);
2100 for (i = 0; i < nbds_max; i++)
2101 nbd_dev_add(i);
2102 mutex_unlock(&nbd_index_mutex);
2103 return 0;
2104 }
2105
2106 static int nbd_exit_cb(int id, void *ptr, void *data)
2107 {
2108 struct list_head *list = (struct list_head *)data;
2109 struct nbd_device *nbd = ptr;
2110
2111 list_add_tail(&nbd->list, list);
2112 return 0;
2113 }
2114
2115 static void __exit nbd_cleanup(void)
2116 {
2117 struct nbd_device *nbd;
2118 LIST_HEAD(del_list);
2119
2120 nbd_dbg_close();
2121
2122 mutex_lock(&nbd_index_mutex);
2123 idr_for_each(&nbd_index_idr, &nbd_exit_cb, &del_list);
2124 mutex_unlock(&nbd_index_mutex);
2125
2126 while (!list_empty(&del_list)) {
2127 nbd = list_first_entry(&del_list, struct nbd_device, list);
2128 list_del_init(&nbd->list);
2129 if (refcount_read(&nbd->refs) != 1)
2130 printk(KERN_ERR "nbd: possibly leaking a device\n");
2131 nbd_put(nbd);
2132 }
2133
2134 idr_destroy(&nbd_index_idr);
2135 genl_unregister_family(&nbd_genl_family);
2136 destroy_workqueue(recv_workqueue);
2137 unregister_blkdev(NBD_MAJOR, "nbd");
2138 }
2139
2140 module_init(nbd_init);
2141 module_exit(nbd_cleanup);
2142
2143 MODULE_DESCRIPTION("Network Block Device");
2144 MODULE_LICENSE("GPL");
2145
2146 module_param(nbds_max, int, 0444);
2147 MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
2148 module_param(max_part, int, 0444);
2149 MODULE_PARM_DESC(max_part, "number of partitions per device (default: 0)");
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