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skd: Use kmem_cache_free
[mirror_ubuntu-bionic-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 = 16;
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 const 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 if (ret < 0)
824 ret = BLK_STS_IOERR;
825 else if (!ret)
826 ret = BLK_STS_OK;
827 complete(&cmd->send_complete);
828
829 return ret;
830 }
831
832 static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
833 bool netlink)
834 {
835 struct nbd_config *config = nbd->config;
836 struct socket *sock;
837 struct nbd_sock **socks;
838 struct nbd_sock *nsock;
839 int err;
840
841 sock = sockfd_lookup(arg, &err);
842 if (!sock)
843 return err;
844
845 if (!netlink && !nbd->task_setup &&
846 !test_bit(NBD_BOUND, &config->runtime_flags))
847 nbd->task_setup = current;
848
849 if (!netlink &&
850 (nbd->task_setup != current ||
851 test_bit(NBD_BOUND, &config->runtime_flags))) {
852 dev_err(disk_to_dev(nbd->disk),
853 "Device being setup by another task");
854 sockfd_put(sock);
855 return -EBUSY;
856 }
857
858 socks = krealloc(config->socks, (config->num_connections + 1) *
859 sizeof(struct nbd_sock *), GFP_KERNEL);
860 if (!socks) {
861 sockfd_put(sock);
862 return -ENOMEM;
863 }
864 nsock = kzalloc(sizeof(struct nbd_sock), GFP_KERNEL);
865 if (!nsock) {
866 sockfd_put(sock);
867 return -ENOMEM;
868 }
869
870 config->socks = socks;
871
872 nsock->fallback_index = -1;
873 nsock->dead = false;
874 mutex_init(&nsock->tx_lock);
875 nsock->sock = sock;
876 nsock->pending = NULL;
877 nsock->sent = 0;
878 nsock->cookie = 0;
879 socks[config->num_connections++] = nsock;
880 atomic_inc(&config->live_connections);
881
882 return 0;
883 }
884
885 static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg)
886 {
887 struct nbd_config *config = nbd->config;
888 struct socket *sock, *old;
889 struct recv_thread_args *args;
890 int i;
891 int err;
892
893 sock = sockfd_lookup(arg, &err);
894 if (!sock)
895 return err;
896
897 args = kzalloc(sizeof(*args), GFP_KERNEL);
898 if (!args) {
899 sockfd_put(sock);
900 return -ENOMEM;
901 }
902
903 for (i = 0; i < config->num_connections; i++) {
904 struct nbd_sock *nsock = config->socks[i];
905
906 if (!nsock->dead)
907 continue;
908
909 mutex_lock(&nsock->tx_lock);
910 if (!nsock->dead) {
911 mutex_unlock(&nsock->tx_lock);
912 continue;
913 }
914 sk_set_memalloc(sock->sk);
915 if (nbd->tag_set.timeout)
916 sock->sk->sk_sndtimeo = nbd->tag_set.timeout;
917 atomic_inc(&config->recv_threads);
918 refcount_inc(&nbd->config_refs);
919 old = nsock->sock;
920 nsock->fallback_index = -1;
921 nsock->sock = sock;
922 nsock->dead = false;
923 INIT_WORK(&args->work, recv_work);
924 args->index = i;
925 args->nbd = nbd;
926 nsock->cookie++;
927 mutex_unlock(&nsock->tx_lock);
928 sockfd_put(old);
929
930 clear_bit(NBD_DISCONNECTED, &config->runtime_flags);
931
932 /* We take the tx_mutex in an error path in the recv_work, so we
933 * need to queue_work outside of the tx_mutex.
934 */
935 queue_work(recv_workqueue, &args->work);
936
937 atomic_inc(&config->live_connections);
938 wake_up(&config->conn_wait);
939 return 0;
940 }
941 sockfd_put(sock);
942 kfree(args);
943 return -ENOSPC;
944 }
945
946 static void nbd_bdev_reset(struct block_device *bdev)
947 {
948 if (bdev->bd_openers > 1)
949 return;
950 bd_set_size(bdev, 0);
951 if (max_part > 0) {
952 blkdev_reread_part(bdev);
953 bdev->bd_invalidated = 1;
954 }
955 }
956
957 static void nbd_parse_flags(struct nbd_device *nbd)
958 {
959 struct nbd_config *config = nbd->config;
960 if (config->flags & NBD_FLAG_READ_ONLY)
961 set_disk_ro(nbd->disk, true);
962 else
963 set_disk_ro(nbd->disk, false);
964 if (config->flags & NBD_FLAG_SEND_TRIM)
965 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
966 if (config->flags & NBD_FLAG_SEND_FLUSH) {
967 if (config->flags & NBD_FLAG_SEND_FUA)
968 blk_queue_write_cache(nbd->disk->queue, true, true);
969 else
970 blk_queue_write_cache(nbd->disk->queue, true, false);
971 }
972 else
973 blk_queue_write_cache(nbd->disk->queue, false, false);
974 }
975
976 static void send_disconnects(struct nbd_device *nbd)
977 {
978 struct nbd_config *config = nbd->config;
979 struct nbd_request request = {
980 .magic = htonl(NBD_REQUEST_MAGIC),
981 .type = htonl(NBD_CMD_DISC),
982 };
983 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
984 struct iov_iter from;
985 int i, ret;
986
987 for (i = 0; i < config->num_connections; i++) {
988 struct nbd_sock *nsock = config->socks[i];
989
990 iov_iter_kvec(&from, WRITE | ITER_KVEC, &iov, 1, sizeof(request));
991 mutex_lock(&nsock->tx_lock);
992 ret = sock_xmit(nbd, i, 1, &from, 0, NULL);
993 if (ret <= 0)
994 dev_err(disk_to_dev(nbd->disk),
995 "Send disconnect failed %d\n", ret);
996 mutex_unlock(&nsock->tx_lock);
997 }
998 }
999
1000 static int nbd_disconnect(struct nbd_device *nbd)
1001 {
1002 struct nbd_config *config = nbd->config;
1003
1004 dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
1005 set_bit(NBD_DISCONNECT_REQUESTED, &config->runtime_flags);
1006 send_disconnects(nbd);
1007 return 0;
1008 }
1009
1010 static void nbd_clear_sock(struct nbd_device *nbd)
1011 {
1012 sock_shutdown(nbd);
1013 nbd_clear_que(nbd);
1014 nbd->task_setup = NULL;
1015 }
1016
1017 static void nbd_config_put(struct nbd_device *nbd)
1018 {
1019 if (refcount_dec_and_mutex_lock(&nbd->config_refs,
1020 &nbd->config_lock)) {
1021 struct nbd_config *config = nbd->config;
1022 nbd_dev_dbg_close(nbd);
1023 nbd_size_clear(nbd);
1024 if (test_and_clear_bit(NBD_HAS_PID_FILE,
1025 &config->runtime_flags))
1026 device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
1027 nbd->task_recv = NULL;
1028 nbd_clear_sock(nbd);
1029 if (config->num_connections) {
1030 int i;
1031 for (i = 0; i < config->num_connections; i++) {
1032 sockfd_put(config->socks[i]->sock);
1033 kfree(config->socks[i]);
1034 }
1035 kfree(config->socks);
1036 }
1037 kfree(nbd->config);
1038 nbd->config = NULL;
1039
1040 nbd->tag_set.timeout = 0;
1041 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
1042
1043 mutex_unlock(&nbd->config_lock);
1044 nbd_put(nbd);
1045 module_put(THIS_MODULE);
1046 }
1047 }
1048
1049 static int nbd_start_device(struct nbd_device *nbd)
1050 {
1051 struct nbd_config *config = nbd->config;
1052 int num_connections = config->num_connections;
1053 int error = 0, i;
1054
1055 if (nbd->task_recv)
1056 return -EBUSY;
1057 if (!config->socks)
1058 return -EINVAL;
1059 if (num_connections > 1 &&
1060 !(config->flags & NBD_FLAG_CAN_MULTI_CONN)) {
1061 dev_err(disk_to_dev(nbd->disk), "server does not support multiple connections per device.\n");
1062 return -EINVAL;
1063 }
1064
1065 blk_mq_update_nr_hw_queues(&nbd->tag_set, config->num_connections);
1066 nbd->task_recv = current;
1067
1068 nbd_parse_flags(nbd);
1069
1070 error = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
1071 if (error) {
1072 dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n");
1073 return error;
1074 }
1075 set_bit(NBD_HAS_PID_FILE, &config->runtime_flags);
1076
1077 nbd_dev_dbg_init(nbd);
1078 for (i = 0; i < num_connections; i++) {
1079 struct recv_thread_args *args;
1080
1081 args = kzalloc(sizeof(*args), GFP_KERNEL);
1082 if (!args) {
1083 sock_shutdown(nbd);
1084 return -ENOMEM;
1085 }
1086 sk_set_memalloc(config->socks[i]->sock->sk);
1087 if (nbd->tag_set.timeout)
1088 config->socks[i]->sock->sk->sk_sndtimeo =
1089 nbd->tag_set.timeout;
1090 atomic_inc(&config->recv_threads);
1091 refcount_inc(&nbd->config_refs);
1092 INIT_WORK(&args->work, recv_work);
1093 args->nbd = nbd;
1094 args->index = i;
1095 queue_work(recv_workqueue, &args->work);
1096 }
1097 return error;
1098 }
1099
1100 static int nbd_start_device_ioctl(struct nbd_device *nbd, struct block_device *bdev)
1101 {
1102 struct nbd_config *config = nbd->config;
1103 int ret;
1104
1105 ret = nbd_start_device(nbd);
1106 if (ret)
1107 return ret;
1108
1109 bd_set_size(bdev, config->bytesize);
1110 if (max_part)
1111 bdev->bd_invalidated = 1;
1112 mutex_unlock(&nbd->config_lock);
1113 ret = wait_event_interruptible(config->recv_wq,
1114 atomic_read(&config->recv_threads) == 0);
1115 if (ret)
1116 sock_shutdown(nbd);
1117 mutex_lock(&nbd->config_lock);
1118 bd_set_size(bdev, 0);
1119 /* user requested, ignore socket errors */
1120 if (test_bit(NBD_DISCONNECT_REQUESTED, &config->runtime_flags))
1121 ret = 0;
1122 if (test_bit(NBD_TIMEDOUT, &config->runtime_flags))
1123 ret = -ETIMEDOUT;
1124 return ret;
1125 }
1126
1127 static void nbd_clear_sock_ioctl(struct nbd_device *nbd,
1128 struct block_device *bdev)
1129 {
1130 sock_shutdown(nbd);
1131 kill_bdev(bdev);
1132 nbd_bdev_reset(bdev);
1133 if (test_and_clear_bit(NBD_HAS_CONFIG_REF,
1134 &nbd->config->runtime_flags))
1135 nbd_config_put(nbd);
1136 }
1137
1138 /* Must be called with config_lock held */
1139 static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
1140 unsigned int cmd, unsigned long arg)
1141 {
1142 struct nbd_config *config = nbd->config;
1143
1144 switch (cmd) {
1145 case NBD_DISCONNECT:
1146 return nbd_disconnect(nbd);
1147 case NBD_CLEAR_SOCK:
1148 nbd_clear_sock_ioctl(nbd, bdev);
1149 return 0;
1150 case NBD_SET_SOCK:
1151 return nbd_add_socket(nbd, arg, false);
1152 case NBD_SET_BLKSIZE:
1153 nbd_size_set(nbd, arg,
1154 div_s64(config->bytesize, arg));
1155 return 0;
1156 case NBD_SET_SIZE:
1157 nbd_size_set(nbd, config->blksize,
1158 div_s64(arg, config->blksize));
1159 return 0;
1160 case NBD_SET_SIZE_BLOCKS:
1161 nbd_size_set(nbd, config->blksize, arg);
1162 return 0;
1163 case NBD_SET_TIMEOUT:
1164 if (arg) {
1165 nbd->tag_set.timeout = arg * HZ;
1166 blk_queue_rq_timeout(nbd->disk->queue, arg * HZ);
1167 }
1168 return 0;
1169
1170 case NBD_SET_FLAGS:
1171 config->flags = arg;
1172 return 0;
1173 case NBD_DO_IT:
1174 return nbd_start_device_ioctl(nbd, bdev);
1175 case NBD_CLEAR_QUE:
1176 /*
1177 * This is for compatibility only. The queue is always cleared
1178 * by NBD_DO_IT or NBD_CLEAR_SOCK.
1179 */
1180 return 0;
1181 case NBD_PRINT_DEBUG:
1182 /*
1183 * For compatibility only, we no longer keep a list of
1184 * outstanding requests.
1185 */
1186 return 0;
1187 }
1188 return -ENOTTY;
1189 }
1190
1191 static int nbd_ioctl(struct block_device *bdev, fmode_t mode,
1192 unsigned int cmd, unsigned long arg)
1193 {
1194 struct nbd_device *nbd = bdev->bd_disk->private_data;
1195 struct nbd_config *config = nbd->config;
1196 int error = -EINVAL;
1197
1198 if (!capable(CAP_SYS_ADMIN))
1199 return -EPERM;
1200
1201 /* The block layer will pass back some non-nbd ioctls in case we have
1202 * special handling for them, but we don't so just return an error.
1203 */
1204 if (_IOC_TYPE(cmd) != 0xab)
1205 return -EINVAL;
1206
1207 mutex_lock(&nbd->config_lock);
1208
1209 /* Don't allow ioctl operations on a nbd device that was created with
1210 * netlink, unless it's DISCONNECT or CLEAR_SOCK, which are fine.
1211 */
1212 if (!test_bit(NBD_BOUND, &config->runtime_flags) ||
1213 (cmd == NBD_DISCONNECT || cmd == NBD_CLEAR_SOCK))
1214 error = __nbd_ioctl(bdev, nbd, cmd, arg);
1215 else
1216 dev_err(nbd_to_dev(nbd), "Cannot use ioctl interface on a netlink controlled device.\n");
1217 mutex_unlock(&nbd->config_lock);
1218 return error;
1219 }
1220
1221 static struct nbd_config *nbd_alloc_config(void)
1222 {
1223 struct nbd_config *config;
1224
1225 config = kzalloc(sizeof(struct nbd_config), GFP_NOFS);
1226 if (!config)
1227 return NULL;
1228 atomic_set(&config->recv_threads, 0);
1229 init_waitqueue_head(&config->recv_wq);
1230 init_waitqueue_head(&config->conn_wait);
1231 config->blksize = 1024;
1232 atomic_set(&config->live_connections, 0);
1233 try_module_get(THIS_MODULE);
1234 return config;
1235 }
1236
1237 static int nbd_open(struct block_device *bdev, fmode_t mode)
1238 {
1239 struct nbd_device *nbd;
1240 int ret = 0;
1241
1242 mutex_lock(&nbd_index_mutex);
1243 nbd = bdev->bd_disk->private_data;
1244 if (!nbd) {
1245 ret = -ENXIO;
1246 goto out;
1247 }
1248 if (!refcount_inc_not_zero(&nbd->refs)) {
1249 ret = -ENXIO;
1250 goto out;
1251 }
1252 if (!refcount_inc_not_zero(&nbd->config_refs)) {
1253 struct nbd_config *config;
1254
1255 mutex_lock(&nbd->config_lock);
1256 if (refcount_inc_not_zero(&nbd->config_refs)) {
1257 mutex_unlock(&nbd->config_lock);
1258 goto out;
1259 }
1260 config = nbd->config = nbd_alloc_config();
1261 if (!config) {
1262 ret = -ENOMEM;
1263 mutex_unlock(&nbd->config_lock);
1264 goto out;
1265 }
1266 refcount_set(&nbd->config_refs, 1);
1267 refcount_inc(&nbd->refs);
1268 mutex_unlock(&nbd->config_lock);
1269 }
1270 out:
1271 mutex_unlock(&nbd_index_mutex);
1272 return ret;
1273 }
1274
1275 static void nbd_release(struct gendisk *disk, fmode_t mode)
1276 {
1277 struct nbd_device *nbd = disk->private_data;
1278 nbd_config_put(nbd);
1279 nbd_put(nbd);
1280 }
1281
1282 static const struct block_device_operations nbd_fops =
1283 {
1284 .owner = THIS_MODULE,
1285 .open = nbd_open,
1286 .release = nbd_release,
1287 .ioctl = nbd_ioctl,
1288 .compat_ioctl = nbd_ioctl,
1289 };
1290
1291 #if IS_ENABLED(CONFIG_DEBUG_FS)
1292
1293 static int nbd_dbg_tasks_show(struct seq_file *s, void *unused)
1294 {
1295 struct nbd_device *nbd = s->private;
1296
1297 if (nbd->task_recv)
1298 seq_printf(s, "recv: %d\n", task_pid_nr(nbd->task_recv));
1299
1300 return 0;
1301 }
1302
1303 static int nbd_dbg_tasks_open(struct inode *inode, struct file *file)
1304 {
1305 return single_open(file, nbd_dbg_tasks_show, inode->i_private);
1306 }
1307
1308 static const struct file_operations nbd_dbg_tasks_ops = {
1309 .open = nbd_dbg_tasks_open,
1310 .read = seq_read,
1311 .llseek = seq_lseek,
1312 .release = single_release,
1313 };
1314
1315 static int nbd_dbg_flags_show(struct seq_file *s, void *unused)
1316 {
1317 struct nbd_device *nbd = s->private;
1318 u32 flags = nbd->config->flags;
1319
1320 seq_printf(s, "Hex: 0x%08x\n\n", flags);
1321
1322 seq_puts(s, "Known flags:\n");
1323
1324 if (flags & NBD_FLAG_HAS_FLAGS)
1325 seq_puts(s, "NBD_FLAG_HAS_FLAGS\n");
1326 if (flags & NBD_FLAG_READ_ONLY)
1327 seq_puts(s, "NBD_FLAG_READ_ONLY\n");
1328 if (flags & NBD_FLAG_SEND_FLUSH)
1329 seq_puts(s, "NBD_FLAG_SEND_FLUSH\n");
1330 if (flags & NBD_FLAG_SEND_FUA)
1331 seq_puts(s, "NBD_FLAG_SEND_FUA\n");
1332 if (flags & NBD_FLAG_SEND_TRIM)
1333 seq_puts(s, "NBD_FLAG_SEND_TRIM\n");
1334
1335 return 0;
1336 }
1337
1338 static int nbd_dbg_flags_open(struct inode *inode, struct file *file)
1339 {
1340 return single_open(file, nbd_dbg_flags_show, inode->i_private);
1341 }
1342
1343 static const struct file_operations nbd_dbg_flags_ops = {
1344 .open = nbd_dbg_flags_open,
1345 .read = seq_read,
1346 .llseek = seq_lseek,
1347 .release = single_release,
1348 };
1349
1350 static int nbd_dev_dbg_init(struct nbd_device *nbd)
1351 {
1352 struct dentry *dir;
1353 struct nbd_config *config = nbd->config;
1354
1355 if (!nbd_dbg_dir)
1356 return -EIO;
1357
1358 dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir);
1359 if (!dir) {
1360 dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s'\n",
1361 nbd_name(nbd));
1362 return -EIO;
1363 }
1364 config->dbg_dir = dir;
1365
1366 debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_ops);
1367 debugfs_create_u64("size_bytes", 0444, dir, &config->bytesize);
1368 debugfs_create_u32("timeout", 0444, dir, &nbd->tag_set.timeout);
1369 debugfs_create_u64("blocksize", 0444, dir, &config->blksize);
1370 debugfs_create_file("flags", 0444, dir, nbd, &nbd_dbg_flags_ops);
1371
1372 return 0;
1373 }
1374
1375 static void nbd_dev_dbg_close(struct nbd_device *nbd)
1376 {
1377 debugfs_remove_recursive(nbd->config->dbg_dir);
1378 }
1379
1380 static int nbd_dbg_init(void)
1381 {
1382 struct dentry *dbg_dir;
1383
1384 dbg_dir = debugfs_create_dir("nbd", NULL);
1385 if (!dbg_dir)
1386 return -EIO;
1387
1388 nbd_dbg_dir = dbg_dir;
1389
1390 return 0;
1391 }
1392
1393 static void nbd_dbg_close(void)
1394 {
1395 debugfs_remove_recursive(nbd_dbg_dir);
1396 }
1397
1398 #else /* IS_ENABLED(CONFIG_DEBUG_FS) */
1399
1400 static int nbd_dev_dbg_init(struct nbd_device *nbd)
1401 {
1402 return 0;
1403 }
1404
1405 static void nbd_dev_dbg_close(struct nbd_device *nbd)
1406 {
1407 }
1408
1409 static int nbd_dbg_init(void)
1410 {
1411 return 0;
1412 }
1413
1414 static void nbd_dbg_close(void)
1415 {
1416 }
1417
1418 #endif
1419
1420 static int nbd_init_request(struct blk_mq_tag_set *set, struct request *rq,
1421 unsigned int hctx_idx, unsigned int numa_node)
1422 {
1423 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq);
1424 cmd->nbd = set->driver_data;
1425 return 0;
1426 }
1427
1428 static const struct blk_mq_ops nbd_mq_ops = {
1429 .queue_rq = nbd_queue_rq,
1430 .complete = nbd_complete_rq,
1431 .init_request = nbd_init_request,
1432 .timeout = nbd_xmit_timeout,
1433 };
1434
1435 static int nbd_dev_add(int index)
1436 {
1437 struct nbd_device *nbd;
1438 struct gendisk *disk;
1439 struct request_queue *q;
1440 int err = -ENOMEM;
1441
1442 nbd = kzalloc(sizeof(struct nbd_device), GFP_KERNEL);
1443 if (!nbd)
1444 goto out;
1445
1446 disk = alloc_disk(1 << part_shift);
1447 if (!disk)
1448 goto out_free_nbd;
1449
1450 if (index >= 0) {
1451 err = idr_alloc(&nbd_index_idr, nbd, index, index + 1,
1452 GFP_KERNEL);
1453 if (err == -ENOSPC)
1454 err = -EEXIST;
1455 } else {
1456 err = idr_alloc(&nbd_index_idr, nbd, 0, 0, GFP_KERNEL);
1457 if (err >= 0)
1458 index = err;
1459 }
1460 if (err < 0)
1461 goto out_free_disk;
1462
1463 nbd->index = index;
1464 nbd->disk = disk;
1465 nbd->tag_set.ops = &nbd_mq_ops;
1466 nbd->tag_set.nr_hw_queues = 1;
1467 nbd->tag_set.queue_depth = 128;
1468 nbd->tag_set.numa_node = NUMA_NO_NODE;
1469 nbd->tag_set.cmd_size = sizeof(struct nbd_cmd);
1470 nbd->tag_set.flags = BLK_MQ_F_SHOULD_MERGE |
1471 BLK_MQ_F_SG_MERGE | BLK_MQ_F_BLOCKING;
1472 nbd->tag_set.driver_data = nbd;
1473
1474 err = blk_mq_alloc_tag_set(&nbd->tag_set);
1475 if (err)
1476 goto out_free_idr;
1477
1478 q = blk_mq_init_queue(&nbd->tag_set);
1479 if (IS_ERR(q)) {
1480 err = PTR_ERR(q);
1481 goto out_free_tags;
1482 }
1483 disk->queue = q;
1484
1485 /*
1486 * Tell the block layer that we are not a rotational device
1487 */
1488 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue);
1489 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, disk->queue);
1490 disk->queue->limits.discard_granularity = 512;
1491 blk_queue_max_discard_sectors(disk->queue, UINT_MAX);
1492 blk_queue_max_segment_size(disk->queue, UINT_MAX);
1493 blk_queue_max_segments(disk->queue, USHRT_MAX);
1494 blk_queue_max_hw_sectors(disk->queue, 65536);
1495 disk->queue->limits.max_sectors = 256;
1496
1497 mutex_init(&nbd->config_lock);
1498 refcount_set(&nbd->config_refs, 0);
1499 refcount_set(&nbd->refs, 1);
1500 INIT_LIST_HEAD(&nbd->list);
1501 disk->major = NBD_MAJOR;
1502 disk->first_minor = index << part_shift;
1503 disk->fops = &nbd_fops;
1504 disk->private_data = nbd;
1505 sprintf(disk->disk_name, "nbd%d", index);
1506 add_disk(disk);
1507 nbd_total_devices++;
1508 return index;
1509
1510 out_free_tags:
1511 blk_mq_free_tag_set(&nbd->tag_set);
1512 out_free_idr:
1513 idr_remove(&nbd_index_idr, index);
1514 out_free_disk:
1515 put_disk(disk);
1516 out_free_nbd:
1517 kfree(nbd);
1518 out:
1519 return err;
1520 }
1521
1522 static int find_free_cb(int id, void *ptr, void *data)
1523 {
1524 struct nbd_device *nbd = ptr;
1525 struct nbd_device **found = data;
1526
1527 if (!refcount_read(&nbd->config_refs)) {
1528 *found = nbd;
1529 return 1;
1530 }
1531 return 0;
1532 }
1533
1534 /* Netlink interface. */
1535 static struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = {
1536 [NBD_ATTR_INDEX] = { .type = NLA_U32 },
1537 [NBD_ATTR_SIZE_BYTES] = { .type = NLA_U64 },
1538 [NBD_ATTR_BLOCK_SIZE_BYTES] = { .type = NLA_U64 },
1539 [NBD_ATTR_TIMEOUT] = { .type = NLA_U64 },
1540 [NBD_ATTR_SERVER_FLAGS] = { .type = NLA_U64 },
1541 [NBD_ATTR_CLIENT_FLAGS] = { .type = NLA_U64 },
1542 [NBD_ATTR_SOCKETS] = { .type = NLA_NESTED},
1543 [NBD_ATTR_DEAD_CONN_TIMEOUT] = { .type = NLA_U64 },
1544 [NBD_ATTR_DEVICE_LIST] = { .type = NLA_NESTED},
1545 };
1546
1547 static struct nla_policy nbd_sock_policy[NBD_SOCK_MAX + 1] = {
1548 [NBD_SOCK_FD] = { .type = NLA_U32 },
1549 };
1550
1551 /* We don't use this right now since we don't parse the incoming list, but we
1552 * still want it here so userspace knows what to expect.
1553 */
1554 static struct nla_policy __attribute__((unused))
1555 nbd_device_policy[NBD_DEVICE_ATTR_MAX + 1] = {
1556 [NBD_DEVICE_INDEX] = { .type = NLA_U32 },
1557 [NBD_DEVICE_CONNECTED] = { .type = NLA_U8 },
1558 };
1559
1560 static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
1561 {
1562 struct nbd_device *nbd = NULL;
1563 struct nbd_config *config;
1564 int index = -1;
1565 int ret;
1566 bool put_dev = false;
1567
1568 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1569 return -EPERM;
1570
1571 if (info->attrs[NBD_ATTR_INDEX])
1572 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1573 if (!info->attrs[NBD_ATTR_SOCKETS]) {
1574 printk(KERN_ERR "nbd: must specify at least one socket\n");
1575 return -EINVAL;
1576 }
1577 if (!info->attrs[NBD_ATTR_SIZE_BYTES]) {
1578 printk(KERN_ERR "nbd: must specify a size in bytes for the device\n");
1579 return -EINVAL;
1580 }
1581 again:
1582 mutex_lock(&nbd_index_mutex);
1583 if (index == -1) {
1584 ret = idr_for_each(&nbd_index_idr, &find_free_cb, &nbd);
1585 if (ret == 0) {
1586 int new_index;
1587 new_index = nbd_dev_add(-1);
1588 if (new_index < 0) {
1589 mutex_unlock(&nbd_index_mutex);
1590 printk(KERN_ERR "nbd: failed to add new device\n");
1591 return ret;
1592 }
1593 nbd = idr_find(&nbd_index_idr, new_index);
1594 }
1595 } else {
1596 nbd = idr_find(&nbd_index_idr, index);
1597 if (!nbd) {
1598 ret = nbd_dev_add(index);
1599 if (ret < 0) {
1600 mutex_unlock(&nbd_index_mutex);
1601 printk(KERN_ERR "nbd: failed to add new device\n");
1602 return ret;
1603 }
1604 nbd = idr_find(&nbd_index_idr, index);
1605 }
1606 }
1607 if (!nbd) {
1608 printk(KERN_ERR "nbd: couldn't find device at index %d\n",
1609 index);
1610 mutex_unlock(&nbd_index_mutex);
1611 return -EINVAL;
1612 }
1613 if (!refcount_inc_not_zero(&nbd->refs)) {
1614 mutex_unlock(&nbd_index_mutex);
1615 if (index == -1)
1616 goto again;
1617 printk(KERN_ERR "nbd: device at index %d is going down\n",
1618 index);
1619 return -EINVAL;
1620 }
1621 mutex_unlock(&nbd_index_mutex);
1622
1623 mutex_lock(&nbd->config_lock);
1624 if (refcount_read(&nbd->config_refs)) {
1625 mutex_unlock(&nbd->config_lock);
1626 nbd_put(nbd);
1627 if (index == -1)
1628 goto again;
1629 printk(KERN_ERR "nbd: nbd%d already in use\n", index);
1630 return -EBUSY;
1631 }
1632 if (WARN_ON(nbd->config)) {
1633 mutex_unlock(&nbd->config_lock);
1634 nbd_put(nbd);
1635 return -EINVAL;
1636 }
1637 config = nbd->config = nbd_alloc_config();
1638 if (!nbd->config) {
1639 mutex_unlock(&nbd->config_lock);
1640 nbd_put(nbd);
1641 printk(KERN_ERR "nbd: couldn't allocate config\n");
1642 return -ENOMEM;
1643 }
1644 refcount_set(&nbd->config_refs, 1);
1645 set_bit(NBD_BOUND, &config->runtime_flags);
1646
1647 if (info->attrs[NBD_ATTR_SIZE_BYTES]) {
1648 u64 bytes = nla_get_u64(info->attrs[NBD_ATTR_SIZE_BYTES]);
1649 nbd_size_set(nbd, config->blksize,
1650 div64_u64(bytes, config->blksize));
1651 }
1652 if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]) {
1653 u64 bsize =
1654 nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]);
1655 nbd_size_set(nbd, bsize, div64_u64(config->bytesize, bsize));
1656 }
1657 if (info->attrs[NBD_ATTR_TIMEOUT]) {
1658 u64 timeout = nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]);
1659 nbd->tag_set.timeout = timeout * HZ;
1660 blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ);
1661 }
1662 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
1663 config->dead_conn_timeout =
1664 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
1665 config->dead_conn_timeout *= HZ;
1666 }
1667 if (info->attrs[NBD_ATTR_SERVER_FLAGS])
1668 config->flags =
1669 nla_get_u64(info->attrs[NBD_ATTR_SERVER_FLAGS]);
1670 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
1671 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
1672 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
1673 set_bit(NBD_DESTROY_ON_DISCONNECT,
1674 &config->runtime_flags);
1675 put_dev = true;
1676 }
1677 }
1678
1679 if (info->attrs[NBD_ATTR_SOCKETS]) {
1680 struct nlattr *attr;
1681 int rem, fd;
1682
1683 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
1684 rem) {
1685 struct nlattr *socks[NBD_SOCK_MAX+1];
1686
1687 if (nla_type(attr) != NBD_SOCK_ITEM) {
1688 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");
1689 ret = -EINVAL;
1690 goto out;
1691 }
1692 ret = nla_parse_nested(socks, NBD_SOCK_MAX, attr,
1693 nbd_sock_policy, info->extack);
1694 if (ret != 0) {
1695 printk(KERN_ERR "nbd: error processing sock list\n");
1696 ret = -EINVAL;
1697 goto out;
1698 }
1699 if (!socks[NBD_SOCK_FD])
1700 continue;
1701 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
1702 ret = nbd_add_socket(nbd, fd, true);
1703 if (ret)
1704 goto out;
1705 }
1706 }
1707 ret = nbd_start_device(nbd);
1708 out:
1709 mutex_unlock(&nbd->config_lock);
1710 if (!ret) {
1711 set_bit(NBD_HAS_CONFIG_REF, &config->runtime_flags);
1712 refcount_inc(&nbd->config_refs);
1713 nbd_connect_reply(info, nbd->index);
1714 }
1715 nbd_config_put(nbd);
1716 if (put_dev)
1717 nbd_put(nbd);
1718 return ret;
1719 }
1720
1721 static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info)
1722 {
1723 struct nbd_device *nbd;
1724 int index;
1725
1726 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1727 return -EPERM;
1728
1729 if (!info->attrs[NBD_ATTR_INDEX]) {
1730 printk(KERN_ERR "nbd: must specify an index to disconnect\n");
1731 return -EINVAL;
1732 }
1733 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1734 mutex_lock(&nbd_index_mutex);
1735 nbd = idr_find(&nbd_index_idr, index);
1736 if (!nbd) {
1737 mutex_unlock(&nbd_index_mutex);
1738 printk(KERN_ERR "nbd: couldn't find device at index %d\n",
1739 index);
1740 return -EINVAL;
1741 }
1742 if (!refcount_inc_not_zero(&nbd->refs)) {
1743 mutex_unlock(&nbd_index_mutex);
1744 printk(KERN_ERR "nbd: device at index %d is going down\n",
1745 index);
1746 return -EINVAL;
1747 }
1748 mutex_unlock(&nbd_index_mutex);
1749 if (!refcount_inc_not_zero(&nbd->config_refs)) {
1750 nbd_put(nbd);
1751 return 0;
1752 }
1753 mutex_lock(&nbd->config_lock);
1754 nbd_disconnect(nbd);
1755 mutex_unlock(&nbd->config_lock);
1756 if (test_and_clear_bit(NBD_HAS_CONFIG_REF,
1757 &nbd->config->runtime_flags))
1758 nbd_config_put(nbd);
1759 nbd_config_put(nbd);
1760 nbd_put(nbd);
1761 return 0;
1762 }
1763
1764 static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info)
1765 {
1766 struct nbd_device *nbd = NULL;
1767 struct nbd_config *config;
1768 int index;
1769 int ret = -EINVAL;
1770 bool put_dev = false;
1771
1772 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1773 return -EPERM;
1774
1775 if (!info->attrs[NBD_ATTR_INDEX]) {
1776 printk(KERN_ERR "nbd: must specify a device to reconfigure\n");
1777 return -EINVAL;
1778 }
1779 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1780 mutex_lock(&nbd_index_mutex);
1781 nbd = idr_find(&nbd_index_idr, index);
1782 if (!nbd) {
1783 mutex_unlock(&nbd_index_mutex);
1784 printk(KERN_ERR "nbd: couldn't find a device at index %d\n",
1785 index);
1786 return -EINVAL;
1787 }
1788 if (!refcount_inc_not_zero(&nbd->refs)) {
1789 mutex_unlock(&nbd_index_mutex);
1790 printk(KERN_ERR "nbd: device at index %d is going down\n",
1791 index);
1792 return -EINVAL;
1793 }
1794 mutex_unlock(&nbd_index_mutex);
1795
1796 if (!refcount_inc_not_zero(&nbd->config_refs)) {
1797 dev_err(nbd_to_dev(nbd),
1798 "not configured, cannot reconfigure\n");
1799 nbd_put(nbd);
1800 return -EINVAL;
1801 }
1802
1803 mutex_lock(&nbd->config_lock);
1804 config = nbd->config;
1805 if (!test_bit(NBD_BOUND, &config->runtime_flags) ||
1806 !nbd->task_recv) {
1807 dev_err(nbd_to_dev(nbd),
1808 "not configured, cannot reconfigure\n");
1809 goto out;
1810 }
1811
1812 if (info->attrs[NBD_ATTR_TIMEOUT]) {
1813 u64 timeout = nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]);
1814 nbd->tag_set.timeout = timeout * HZ;
1815 blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ);
1816 }
1817 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
1818 config->dead_conn_timeout =
1819 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
1820 config->dead_conn_timeout *= HZ;
1821 }
1822 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
1823 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
1824 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
1825 if (!test_and_set_bit(NBD_DESTROY_ON_DISCONNECT,
1826 &config->runtime_flags))
1827 put_dev = true;
1828 } else {
1829 if (test_and_clear_bit(NBD_DESTROY_ON_DISCONNECT,
1830 &config->runtime_flags))
1831 refcount_inc(&nbd->refs);
1832 }
1833 }
1834
1835 if (info->attrs[NBD_ATTR_SOCKETS]) {
1836 struct nlattr *attr;
1837 int rem, fd;
1838
1839 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
1840 rem) {
1841 struct nlattr *socks[NBD_SOCK_MAX+1];
1842
1843 if (nla_type(attr) != NBD_SOCK_ITEM) {
1844 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");
1845 ret = -EINVAL;
1846 goto out;
1847 }
1848 ret = nla_parse_nested(socks, NBD_SOCK_MAX, attr,
1849 nbd_sock_policy, info->extack);
1850 if (ret != 0) {
1851 printk(KERN_ERR "nbd: error processing sock list\n");
1852 ret = -EINVAL;
1853 goto out;
1854 }
1855 if (!socks[NBD_SOCK_FD])
1856 continue;
1857 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
1858 ret = nbd_reconnect_socket(nbd, fd);
1859 if (ret) {
1860 if (ret == -ENOSPC)
1861 ret = 0;
1862 goto out;
1863 }
1864 dev_info(nbd_to_dev(nbd), "reconnected socket\n");
1865 }
1866 }
1867 out:
1868 mutex_unlock(&nbd->config_lock);
1869 nbd_config_put(nbd);
1870 nbd_put(nbd);
1871 if (put_dev)
1872 nbd_put(nbd);
1873 return ret;
1874 }
1875
1876 static const struct genl_ops nbd_connect_genl_ops[] = {
1877 {
1878 .cmd = NBD_CMD_CONNECT,
1879 .policy = nbd_attr_policy,
1880 .doit = nbd_genl_connect,
1881 },
1882 {
1883 .cmd = NBD_CMD_DISCONNECT,
1884 .policy = nbd_attr_policy,
1885 .doit = nbd_genl_disconnect,
1886 },
1887 {
1888 .cmd = NBD_CMD_RECONFIGURE,
1889 .policy = nbd_attr_policy,
1890 .doit = nbd_genl_reconfigure,
1891 },
1892 {
1893 .cmd = NBD_CMD_STATUS,
1894 .policy = nbd_attr_policy,
1895 .doit = nbd_genl_status,
1896 },
1897 };
1898
1899 static const struct genl_multicast_group nbd_mcast_grps[] = {
1900 { .name = NBD_GENL_MCAST_GROUP_NAME, },
1901 };
1902
1903 static struct genl_family nbd_genl_family __ro_after_init = {
1904 .hdrsize = 0,
1905 .name = NBD_GENL_FAMILY_NAME,
1906 .version = NBD_GENL_VERSION,
1907 .module = THIS_MODULE,
1908 .ops = nbd_connect_genl_ops,
1909 .n_ops = ARRAY_SIZE(nbd_connect_genl_ops),
1910 .maxattr = NBD_ATTR_MAX,
1911 .mcgrps = nbd_mcast_grps,
1912 .n_mcgrps = ARRAY_SIZE(nbd_mcast_grps),
1913 };
1914
1915 static int populate_nbd_status(struct nbd_device *nbd, struct sk_buff *reply)
1916 {
1917 struct nlattr *dev_opt;
1918 u8 connected = 0;
1919 int ret;
1920
1921 /* This is a little racey, but for status it's ok. The
1922 * reason we don't take a ref here is because we can't
1923 * take a ref in the index == -1 case as we would need
1924 * to put under the nbd_index_mutex, which could
1925 * deadlock if we are configured to remove ourselves
1926 * once we're disconnected.
1927 */
1928 if (refcount_read(&nbd->config_refs))
1929 connected = 1;
1930 dev_opt = nla_nest_start(reply, NBD_DEVICE_ITEM);
1931 if (!dev_opt)
1932 return -EMSGSIZE;
1933 ret = nla_put_u32(reply, NBD_DEVICE_INDEX, nbd->index);
1934 if (ret)
1935 return -EMSGSIZE;
1936 ret = nla_put_u8(reply, NBD_DEVICE_CONNECTED,
1937 connected);
1938 if (ret)
1939 return -EMSGSIZE;
1940 nla_nest_end(reply, dev_opt);
1941 return 0;
1942 }
1943
1944 static int status_cb(int id, void *ptr, void *data)
1945 {
1946 struct nbd_device *nbd = ptr;
1947 return populate_nbd_status(nbd, (struct sk_buff *)data);
1948 }
1949
1950 static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info)
1951 {
1952 struct nlattr *dev_list;
1953 struct sk_buff *reply;
1954 void *reply_head;
1955 size_t msg_size;
1956 int index = -1;
1957 int ret = -ENOMEM;
1958
1959 if (info->attrs[NBD_ATTR_INDEX])
1960 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1961
1962 mutex_lock(&nbd_index_mutex);
1963
1964 msg_size = nla_total_size(nla_attr_size(sizeof(u32)) +
1965 nla_attr_size(sizeof(u8)));
1966 msg_size *= (index == -1) ? nbd_total_devices : 1;
1967
1968 reply = genlmsg_new(msg_size, GFP_KERNEL);
1969 if (!reply)
1970 goto out;
1971 reply_head = genlmsg_put_reply(reply, info, &nbd_genl_family, 0,
1972 NBD_CMD_STATUS);
1973 if (!reply_head) {
1974 nlmsg_free(reply);
1975 goto out;
1976 }
1977
1978 dev_list = nla_nest_start(reply, NBD_ATTR_DEVICE_LIST);
1979 if (index == -1) {
1980 ret = idr_for_each(&nbd_index_idr, &status_cb, reply);
1981 if (ret) {
1982 nlmsg_free(reply);
1983 goto out;
1984 }
1985 } else {
1986 struct nbd_device *nbd;
1987 nbd = idr_find(&nbd_index_idr, index);
1988 if (nbd) {
1989 ret = populate_nbd_status(nbd, reply);
1990 if (ret) {
1991 nlmsg_free(reply);
1992 goto out;
1993 }
1994 }
1995 }
1996 nla_nest_end(reply, dev_list);
1997 genlmsg_end(reply, reply_head);
1998 genlmsg_reply(reply, info);
1999 ret = 0;
2000 out:
2001 mutex_unlock(&nbd_index_mutex);
2002 return ret;
2003 }
2004
2005 static void nbd_connect_reply(struct genl_info *info, int index)
2006 {
2007 struct sk_buff *skb;
2008 void *msg_head;
2009 int ret;
2010
2011 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2012 if (!skb)
2013 return;
2014 msg_head = genlmsg_put_reply(skb, info, &nbd_genl_family, 0,
2015 NBD_CMD_CONNECT);
2016 if (!msg_head) {
2017 nlmsg_free(skb);
2018 return;
2019 }
2020 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2021 if (ret) {
2022 nlmsg_free(skb);
2023 return;
2024 }
2025 genlmsg_end(skb, msg_head);
2026 genlmsg_reply(skb, info);
2027 }
2028
2029 static void nbd_mcast_index(int index)
2030 {
2031 struct sk_buff *skb;
2032 void *msg_head;
2033 int ret;
2034
2035 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2036 if (!skb)
2037 return;
2038 msg_head = genlmsg_put(skb, 0, 0, &nbd_genl_family, 0,
2039 NBD_CMD_LINK_DEAD);
2040 if (!msg_head) {
2041 nlmsg_free(skb);
2042 return;
2043 }
2044 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2045 if (ret) {
2046 nlmsg_free(skb);
2047 return;
2048 }
2049 genlmsg_end(skb, msg_head);
2050 genlmsg_multicast(&nbd_genl_family, skb, 0, 0, GFP_KERNEL);
2051 }
2052
2053 static void nbd_dead_link_work(struct work_struct *work)
2054 {
2055 struct link_dead_args *args = container_of(work, struct link_dead_args,
2056 work);
2057 nbd_mcast_index(args->index);
2058 kfree(args);
2059 }
2060
2061 static int __init nbd_init(void)
2062 {
2063 int i;
2064
2065 BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
2066
2067 if (max_part < 0) {
2068 printk(KERN_ERR "nbd: max_part must be >= 0\n");
2069 return -EINVAL;
2070 }
2071
2072 part_shift = 0;
2073 if (max_part > 0) {
2074 part_shift = fls(max_part);
2075
2076 /*
2077 * Adjust max_part according to part_shift as it is exported
2078 * to user space so that user can know the max number of
2079 * partition kernel should be able to manage.
2080 *
2081 * Note that -1 is required because partition 0 is reserved
2082 * for the whole disk.
2083 */
2084 max_part = (1UL << part_shift) - 1;
2085 }
2086
2087 if ((1UL << part_shift) > DISK_MAX_PARTS)
2088 return -EINVAL;
2089
2090 if (nbds_max > 1UL << (MINORBITS - part_shift))
2091 return -EINVAL;
2092 recv_workqueue = alloc_workqueue("knbd-recv",
2093 WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
2094 if (!recv_workqueue)
2095 return -ENOMEM;
2096
2097 if (register_blkdev(NBD_MAJOR, "nbd")) {
2098 destroy_workqueue(recv_workqueue);
2099 return -EIO;
2100 }
2101
2102 if (genl_register_family(&nbd_genl_family)) {
2103 unregister_blkdev(NBD_MAJOR, "nbd");
2104 destroy_workqueue(recv_workqueue);
2105 return -EINVAL;
2106 }
2107 nbd_dbg_init();
2108
2109 mutex_lock(&nbd_index_mutex);
2110 for (i = 0; i < nbds_max; i++)
2111 nbd_dev_add(i);
2112 mutex_unlock(&nbd_index_mutex);
2113 return 0;
2114 }
2115
2116 static int nbd_exit_cb(int id, void *ptr, void *data)
2117 {
2118 struct list_head *list = (struct list_head *)data;
2119 struct nbd_device *nbd = ptr;
2120
2121 list_add_tail(&nbd->list, list);
2122 return 0;
2123 }
2124
2125 static void __exit nbd_cleanup(void)
2126 {
2127 struct nbd_device *nbd;
2128 LIST_HEAD(del_list);
2129
2130 nbd_dbg_close();
2131
2132 mutex_lock(&nbd_index_mutex);
2133 idr_for_each(&nbd_index_idr, &nbd_exit_cb, &del_list);
2134 mutex_unlock(&nbd_index_mutex);
2135
2136 while (!list_empty(&del_list)) {
2137 nbd = list_first_entry(&del_list, struct nbd_device, list);
2138 list_del_init(&nbd->list);
2139 if (refcount_read(&nbd->refs) != 1)
2140 printk(KERN_ERR "nbd: possibly leaking a device\n");
2141 nbd_put(nbd);
2142 }
2143
2144 idr_destroy(&nbd_index_idr);
2145 genl_unregister_family(&nbd_genl_family);
2146 destroy_workqueue(recv_workqueue);
2147 unregister_blkdev(NBD_MAJOR, "nbd");
2148 }
2149
2150 module_init(nbd_init);
2151 module_exit(nbd_cleanup);
2152
2153 MODULE_DESCRIPTION("Network Block Device");
2154 MODULE_LICENSE("GPL");
2155
2156 module_param(nbds_max, int, 0444);
2157 MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
2158 module_param(max_part, int, 0444);
2159 MODULE_PARM_DESC(max_part, "number of partitions per device (default: 16)");
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