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genetlink: make policy common to family
[mirror_ubuntu-jammy-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 #define NBD_DISCONNECT_ON_CLOSE 7
80
81 struct nbd_config {
82 u32 flags;
83 unsigned long runtime_flags;
84 u64 dead_conn_timeout;
85
86 struct nbd_sock **socks;
87 int num_connections;
88 atomic_t live_connections;
89 wait_queue_head_t conn_wait;
90
91 atomic_t recv_threads;
92 wait_queue_head_t recv_wq;
93 loff_t blksize;
94 loff_t bytesize;
95 #if IS_ENABLED(CONFIG_DEBUG_FS)
96 struct dentry *dbg_dir;
97 #endif
98 };
99
100 struct nbd_device {
101 struct blk_mq_tag_set tag_set;
102
103 int index;
104 refcount_t config_refs;
105 refcount_t refs;
106 struct nbd_config *config;
107 struct mutex config_lock;
108 struct gendisk *disk;
109
110 struct list_head list;
111 struct task_struct *task_recv;
112 struct task_struct *task_setup;
113 };
114
115 #define NBD_CMD_REQUEUED 1
116
117 struct nbd_cmd {
118 struct nbd_device *nbd;
119 struct mutex lock;
120 int index;
121 int cookie;
122 blk_status_t status;
123 unsigned long flags;
124 u32 cmd_cookie;
125 };
126
127 #if IS_ENABLED(CONFIG_DEBUG_FS)
128 static struct dentry *nbd_dbg_dir;
129 #endif
130
131 #define nbd_name(nbd) ((nbd)->disk->disk_name)
132
133 #define NBD_MAGIC 0x68797548
134
135 static unsigned int nbds_max = 16;
136 static int max_part = 16;
137 static struct workqueue_struct *recv_workqueue;
138 static int part_shift;
139
140 static int nbd_dev_dbg_init(struct nbd_device *nbd);
141 static void nbd_dev_dbg_close(struct nbd_device *nbd);
142 static void nbd_config_put(struct nbd_device *nbd);
143 static void nbd_connect_reply(struct genl_info *info, int index);
144 static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info);
145 static void nbd_dead_link_work(struct work_struct *work);
146 static void nbd_disconnect_and_put(struct nbd_device *nbd);
147
148 static inline struct device *nbd_to_dev(struct nbd_device *nbd)
149 {
150 return disk_to_dev(nbd->disk);
151 }
152
153 static void nbd_requeue_cmd(struct nbd_cmd *cmd)
154 {
155 struct request *req = blk_mq_rq_from_pdu(cmd);
156
157 if (!test_and_set_bit(NBD_CMD_REQUEUED, &cmd->flags))
158 blk_mq_requeue_request(req, true);
159 }
160
161 #define NBD_COOKIE_BITS 32
162
163 static u64 nbd_cmd_handle(struct nbd_cmd *cmd)
164 {
165 struct request *req = blk_mq_rq_from_pdu(cmd);
166 u32 tag = blk_mq_unique_tag(req);
167 u64 cookie = cmd->cmd_cookie;
168
169 return (cookie << NBD_COOKIE_BITS) | tag;
170 }
171
172 static u32 nbd_handle_to_tag(u64 handle)
173 {
174 return (u32)handle;
175 }
176
177 static u32 nbd_handle_to_cookie(u64 handle)
178 {
179 return (u32)(handle >> NBD_COOKIE_BITS);
180 }
181
182 static const char *nbdcmd_to_ascii(int cmd)
183 {
184 switch (cmd) {
185 case NBD_CMD_READ: return "read";
186 case NBD_CMD_WRITE: return "write";
187 case NBD_CMD_DISC: return "disconnect";
188 case NBD_CMD_FLUSH: return "flush";
189 case NBD_CMD_TRIM: return "trim/discard";
190 }
191 return "invalid";
192 }
193
194 static ssize_t pid_show(struct device *dev,
195 struct device_attribute *attr, char *buf)
196 {
197 struct gendisk *disk = dev_to_disk(dev);
198 struct nbd_device *nbd = (struct nbd_device *)disk->private_data;
199
200 return sprintf(buf, "%d\n", task_pid_nr(nbd->task_recv));
201 }
202
203 static const struct device_attribute pid_attr = {
204 .attr = { .name = "pid", .mode = 0444},
205 .show = pid_show,
206 };
207
208 static void nbd_dev_remove(struct nbd_device *nbd)
209 {
210 struct gendisk *disk = nbd->disk;
211 struct request_queue *q;
212
213 if (disk) {
214 q = disk->queue;
215 del_gendisk(disk);
216 blk_cleanup_queue(q);
217 blk_mq_free_tag_set(&nbd->tag_set);
218 disk->private_data = NULL;
219 put_disk(disk);
220 }
221 kfree(nbd);
222 }
223
224 static void nbd_put(struct nbd_device *nbd)
225 {
226 if (refcount_dec_and_mutex_lock(&nbd->refs,
227 &nbd_index_mutex)) {
228 idr_remove(&nbd_index_idr, nbd->index);
229 mutex_unlock(&nbd_index_mutex);
230 nbd_dev_remove(nbd);
231 }
232 }
233
234 static int nbd_disconnected(struct nbd_config *config)
235 {
236 return test_bit(NBD_DISCONNECTED, &config->runtime_flags) ||
237 test_bit(NBD_DISCONNECT_REQUESTED, &config->runtime_flags);
238 }
239
240 static void nbd_mark_nsock_dead(struct nbd_device *nbd, struct nbd_sock *nsock,
241 int notify)
242 {
243 if (!nsock->dead && notify && !nbd_disconnected(nbd->config)) {
244 struct link_dead_args *args;
245 args = kmalloc(sizeof(struct link_dead_args), GFP_NOIO);
246 if (args) {
247 INIT_WORK(&args->work, nbd_dead_link_work);
248 args->index = nbd->index;
249 queue_work(system_wq, &args->work);
250 }
251 }
252 if (!nsock->dead) {
253 kernel_sock_shutdown(nsock->sock, SHUT_RDWR);
254 if (atomic_dec_return(&nbd->config->live_connections) == 0) {
255 if (test_and_clear_bit(NBD_DISCONNECT_REQUESTED,
256 &nbd->config->runtime_flags)) {
257 set_bit(NBD_DISCONNECTED,
258 &nbd->config->runtime_flags);
259 dev_info(nbd_to_dev(nbd),
260 "Disconnected due to user request.\n");
261 }
262 }
263 }
264 nsock->dead = true;
265 nsock->pending = NULL;
266 nsock->sent = 0;
267 }
268
269 static void nbd_size_clear(struct nbd_device *nbd)
270 {
271 if (nbd->config->bytesize) {
272 set_capacity(nbd->disk, 0);
273 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
274 }
275 }
276
277 static void nbd_size_update(struct nbd_device *nbd)
278 {
279 struct nbd_config *config = nbd->config;
280 struct block_device *bdev = bdget_disk(nbd->disk, 0);
281
282 if (config->flags & NBD_FLAG_SEND_TRIM) {
283 nbd->disk->queue->limits.discard_granularity = config->blksize;
284 nbd->disk->queue->limits.discard_alignment = config->blksize;
285 blk_queue_max_discard_sectors(nbd->disk->queue, UINT_MAX);
286 }
287 blk_queue_logical_block_size(nbd->disk->queue, config->blksize);
288 blk_queue_physical_block_size(nbd->disk->queue, config->blksize);
289 set_capacity(nbd->disk, config->bytesize >> 9);
290 if (bdev) {
291 if (bdev->bd_disk) {
292 bd_set_size(bdev, config->bytesize);
293 set_blocksize(bdev, config->blksize);
294 } else
295 bdev->bd_invalidated = 1;
296 bdput(bdev);
297 }
298 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
299 }
300
301 static void nbd_size_set(struct nbd_device *nbd, loff_t blocksize,
302 loff_t nr_blocks)
303 {
304 struct nbd_config *config = nbd->config;
305 config->blksize = blocksize;
306 config->bytesize = blocksize * nr_blocks;
307 if (nbd->task_recv != NULL)
308 nbd_size_update(nbd);
309 }
310
311 static void nbd_complete_rq(struct request *req)
312 {
313 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
314
315 dev_dbg(nbd_to_dev(cmd->nbd), "request %p: %s\n", req,
316 cmd->status ? "failed" : "done");
317
318 blk_mq_end_request(req, cmd->status);
319 }
320
321 /*
322 * Forcibly shutdown the socket causing all listeners to error
323 */
324 static void sock_shutdown(struct nbd_device *nbd)
325 {
326 struct nbd_config *config = nbd->config;
327 int i;
328
329 if (config->num_connections == 0)
330 return;
331 if (test_and_set_bit(NBD_DISCONNECTED, &config->runtime_flags))
332 return;
333
334 for (i = 0; i < config->num_connections; i++) {
335 struct nbd_sock *nsock = config->socks[i];
336 mutex_lock(&nsock->tx_lock);
337 nbd_mark_nsock_dead(nbd, nsock, 0);
338 mutex_unlock(&nsock->tx_lock);
339 }
340 dev_warn(disk_to_dev(nbd->disk), "shutting down sockets\n");
341 }
342
343 static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
344 bool reserved)
345 {
346 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
347 struct nbd_device *nbd = cmd->nbd;
348 struct nbd_config *config;
349
350 if (!refcount_inc_not_zero(&nbd->config_refs)) {
351 cmd->status = BLK_STS_TIMEOUT;
352 goto done;
353 }
354 config = nbd->config;
355
356 if (!mutex_trylock(&cmd->lock))
357 return BLK_EH_RESET_TIMER;
358
359 if (config->num_connections > 1) {
360 dev_err_ratelimited(nbd_to_dev(nbd),
361 "Connection timed out, retrying (%d/%d alive)\n",
362 atomic_read(&config->live_connections),
363 config->num_connections);
364 /*
365 * Hooray we have more connections, requeue this IO, the submit
366 * path will put it on a real connection.
367 */
368 if (config->socks && config->num_connections > 1) {
369 if (cmd->index < config->num_connections) {
370 struct nbd_sock *nsock =
371 config->socks[cmd->index];
372 mutex_lock(&nsock->tx_lock);
373 /* We can have multiple outstanding requests, so
374 * we don't want to mark the nsock dead if we've
375 * already reconnected with a new socket, so
376 * only mark it dead if its the same socket we
377 * were sent out on.
378 */
379 if (cmd->cookie == nsock->cookie)
380 nbd_mark_nsock_dead(nbd, nsock, 1);
381 mutex_unlock(&nsock->tx_lock);
382 }
383 mutex_unlock(&cmd->lock);
384 nbd_requeue_cmd(cmd);
385 nbd_config_put(nbd);
386 return BLK_EH_DONE;
387 }
388 } else {
389 dev_err_ratelimited(nbd_to_dev(nbd),
390 "Connection timed out\n");
391 }
392 set_bit(NBD_TIMEDOUT, &config->runtime_flags);
393 cmd->status = BLK_STS_IOERR;
394 mutex_unlock(&cmd->lock);
395 sock_shutdown(nbd);
396 nbd_config_put(nbd);
397 done:
398 blk_mq_complete_request(req);
399 return BLK_EH_DONE;
400 }
401
402 /*
403 * Send or receive packet.
404 */
405 static int sock_xmit(struct nbd_device *nbd, int index, int send,
406 struct iov_iter *iter, int msg_flags, int *sent)
407 {
408 struct nbd_config *config = nbd->config;
409 struct socket *sock = config->socks[index]->sock;
410 int result;
411 struct msghdr msg;
412 unsigned int noreclaim_flag;
413
414 if (unlikely(!sock)) {
415 dev_err_ratelimited(disk_to_dev(nbd->disk),
416 "Attempted %s on closed socket in sock_xmit\n",
417 (send ? "send" : "recv"));
418 return -EINVAL;
419 }
420
421 msg.msg_iter = *iter;
422
423 noreclaim_flag = memalloc_noreclaim_save();
424 do {
425 sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC;
426 msg.msg_name = NULL;
427 msg.msg_namelen = 0;
428 msg.msg_control = NULL;
429 msg.msg_controllen = 0;
430 msg.msg_flags = msg_flags | MSG_NOSIGNAL;
431
432 if (send)
433 result = sock_sendmsg(sock, &msg);
434 else
435 result = sock_recvmsg(sock, &msg, msg.msg_flags);
436
437 if (result <= 0) {
438 if (result == 0)
439 result = -EPIPE; /* short read */
440 break;
441 }
442 if (sent)
443 *sent += result;
444 } while (msg_data_left(&msg));
445
446 memalloc_noreclaim_restore(noreclaim_flag);
447
448 return result;
449 }
450
451 /*
452 * Different settings for sk->sk_sndtimeo can result in different return values
453 * if there is a signal pending when we enter sendmsg, because reasons?
454 */
455 static inline int was_interrupted(int result)
456 {
457 return result == -ERESTARTSYS || result == -EINTR;
458 }
459
460 /* always call with the tx_lock held */
461 static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
462 {
463 struct request *req = blk_mq_rq_from_pdu(cmd);
464 struct nbd_config *config = nbd->config;
465 struct nbd_sock *nsock = config->socks[index];
466 int result;
467 struct nbd_request request = {.magic = htonl(NBD_REQUEST_MAGIC)};
468 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
469 struct iov_iter from;
470 unsigned long size = blk_rq_bytes(req);
471 struct bio *bio;
472 u64 handle;
473 u32 type;
474 u32 nbd_cmd_flags = 0;
475 int sent = nsock->sent, skip = 0;
476
477 iov_iter_kvec(&from, WRITE, &iov, 1, sizeof(request));
478
479 switch (req_op(req)) {
480 case REQ_OP_DISCARD:
481 type = NBD_CMD_TRIM;
482 break;
483 case REQ_OP_FLUSH:
484 type = NBD_CMD_FLUSH;
485 break;
486 case REQ_OP_WRITE:
487 type = NBD_CMD_WRITE;
488 break;
489 case REQ_OP_READ:
490 type = NBD_CMD_READ;
491 break;
492 default:
493 return -EIO;
494 }
495
496 if (rq_data_dir(req) == WRITE &&
497 (config->flags & NBD_FLAG_READ_ONLY)) {
498 dev_err_ratelimited(disk_to_dev(nbd->disk),
499 "Write on read-only\n");
500 return -EIO;
501 }
502
503 if (req->cmd_flags & REQ_FUA)
504 nbd_cmd_flags |= NBD_CMD_FLAG_FUA;
505
506 /* We did a partial send previously, and we at least sent the whole
507 * request struct, so just go and send the rest of the pages in the
508 * request.
509 */
510 if (sent) {
511 if (sent >= sizeof(request)) {
512 skip = sent - sizeof(request);
513 goto send_pages;
514 }
515 iov_iter_advance(&from, sent);
516 } else {
517 cmd->cmd_cookie++;
518 }
519 cmd->index = index;
520 cmd->cookie = nsock->cookie;
521 request.type = htonl(type | nbd_cmd_flags);
522 if (type != NBD_CMD_FLUSH) {
523 request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
524 request.len = htonl(size);
525 }
526 handle = nbd_cmd_handle(cmd);
527 memcpy(request.handle, &handle, sizeof(handle));
528
529 dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n",
530 req, nbdcmd_to_ascii(type),
531 (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req));
532 result = sock_xmit(nbd, index, 1, &from,
533 (type == NBD_CMD_WRITE) ? MSG_MORE : 0, &sent);
534 if (result <= 0) {
535 if (was_interrupted(result)) {
536 /* If we havne't sent anything we can just return BUSY,
537 * however if we have sent something we need to make
538 * sure we only allow this req to be sent until we are
539 * completely done.
540 */
541 if (sent) {
542 nsock->pending = req;
543 nsock->sent = sent;
544 }
545 set_bit(NBD_CMD_REQUEUED, &cmd->flags);
546 return BLK_STS_RESOURCE;
547 }
548 dev_err_ratelimited(disk_to_dev(nbd->disk),
549 "Send control failed (result %d)\n", result);
550 return -EAGAIN;
551 }
552 send_pages:
553 if (type != NBD_CMD_WRITE)
554 goto out;
555
556 bio = req->bio;
557 while (bio) {
558 struct bio *next = bio->bi_next;
559 struct bvec_iter iter;
560 struct bio_vec bvec;
561
562 bio_for_each_segment(bvec, bio, iter) {
563 bool is_last = !next && bio_iter_last(bvec, iter);
564 int flags = is_last ? 0 : MSG_MORE;
565
566 dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n",
567 req, bvec.bv_len);
568 iov_iter_bvec(&from, WRITE, &bvec, 1, bvec.bv_len);
569 if (skip) {
570 if (skip >= iov_iter_count(&from)) {
571 skip -= iov_iter_count(&from);
572 continue;
573 }
574 iov_iter_advance(&from, skip);
575 skip = 0;
576 }
577 result = sock_xmit(nbd, index, 1, &from, flags, &sent);
578 if (result <= 0) {
579 if (was_interrupted(result)) {
580 /* We've already sent the header, we
581 * have no choice but to set pending and
582 * return BUSY.
583 */
584 nsock->pending = req;
585 nsock->sent = sent;
586 set_bit(NBD_CMD_REQUEUED, &cmd->flags);
587 return BLK_STS_RESOURCE;
588 }
589 dev_err(disk_to_dev(nbd->disk),
590 "Send data failed (result %d)\n",
591 result);
592 return -EAGAIN;
593 }
594 /*
595 * The completion might already have come in,
596 * so break for the last one instead of letting
597 * the iterator do it. This prevents use-after-free
598 * of the bio.
599 */
600 if (is_last)
601 break;
602 }
603 bio = next;
604 }
605 out:
606 nsock->pending = NULL;
607 nsock->sent = 0;
608 return 0;
609 }
610
611 /* NULL returned = something went wrong, inform userspace */
612 static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
613 {
614 struct nbd_config *config = nbd->config;
615 int result;
616 struct nbd_reply reply;
617 struct nbd_cmd *cmd;
618 struct request *req = NULL;
619 u64 handle;
620 u16 hwq;
621 u32 tag;
622 struct kvec iov = {.iov_base = &reply, .iov_len = sizeof(reply)};
623 struct iov_iter to;
624 int ret = 0;
625
626 reply.magic = 0;
627 iov_iter_kvec(&to, READ, &iov, 1, sizeof(reply));
628 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
629 if (result <= 0) {
630 if (!nbd_disconnected(config))
631 dev_err(disk_to_dev(nbd->disk),
632 "Receive control failed (result %d)\n", result);
633 return ERR_PTR(result);
634 }
635
636 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) {
637 dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n",
638 (unsigned long)ntohl(reply.magic));
639 return ERR_PTR(-EPROTO);
640 }
641
642 memcpy(&handle, reply.handle, sizeof(handle));
643 tag = nbd_handle_to_tag(handle);
644 hwq = blk_mq_unique_tag_to_hwq(tag);
645 if (hwq < nbd->tag_set.nr_hw_queues)
646 req = blk_mq_tag_to_rq(nbd->tag_set.tags[hwq],
647 blk_mq_unique_tag_to_tag(tag));
648 if (!req || !blk_mq_request_started(req)) {
649 dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%d) %p\n",
650 tag, req);
651 return ERR_PTR(-ENOENT);
652 }
653 cmd = blk_mq_rq_to_pdu(req);
654
655 mutex_lock(&cmd->lock);
656 if (cmd->cmd_cookie != nbd_handle_to_cookie(handle)) {
657 dev_err(disk_to_dev(nbd->disk), "Double reply on req %p, cmd_cookie %u, handle cookie %u\n",
658 req, cmd->cmd_cookie, nbd_handle_to_cookie(handle));
659 ret = -ENOENT;
660 goto out;
661 }
662 if (test_bit(NBD_CMD_REQUEUED, &cmd->flags)) {
663 dev_err(disk_to_dev(nbd->disk), "Raced with timeout on req %p\n",
664 req);
665 ret = -ENOENT;
666 goto out;
667 }
668 if (ntohl(reply.error)) {
669 dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n",
670 ntohl(reply.error));
671 cmd->status = BLK_STS_IOERR;
672 goto out;
673 }
674
675 dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", req);
676 if (rq_data_dir(req) != WRITE) {
677 struct req_iterator iter;
678 struct bio_vec bvec;
679
680 rq_for_each_segment(bvec, req, iter) {
681 iov_iter_bvec(&to, READ, &bvec, 1, bvec.bv_len);
682 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
683 if (result <= 0) {
684 dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
685 result);
686 /*
687 * If we've disconnected or we only have 1
688 * connection then we need to make sure we
689 * complete this request, otherwise error out
690 * and let the timeout stuff handle resubmitting
691 * this request onto another connection.
692 */
693 if (nbd_disconnected(config) ||
694 config->num_connections <= 1) {
695 cmd->status = BLK_STS_IOERR;
696 goto out;
697 }
698 ret = -EIO;
699 goto out;
700 }
701 dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n",
702 req, bvec.bv_len);
703 }
704 }
705 out:
706 mutex_unlock(&cmd->lock);
707 return ret ? ERR_PTR(ret) : cmd;
708 }
709
710 static void recv_work(struct work_struct *work)
711 {
712 struct recv_thread_args *args = container_of(work,
713 struct recv_thread_args,
714 work);
715 struct nbd_device *nbd = args->nbd;
716 struct nbd_config *config = nbd->config;
717 struct nbd_cmd *cmd;
718
719 while (1) {
720 cmd = nbd_read_stat(nbd, args->index);
721 if (IS_ERR(cmd)) {
722 struct nbd_sock *nsock = config->socks[args->index];
723
724 mutex_lock(&nsock->tx_lock);
725 nbd_mark_nsock_dead(nbd, nsock, 1);
726 mutex_unlock(&nsock->tx_lock);
727 break;
728 }
729
730 blk_mq_complete_request(blk_mq_rq_from_pdu(cmd));
731 }
732 atomic_dec(&config->recv_threads);
733 wake_up(&config->recv_wq);
734 nbd_config_put(nbd);
735 kfree(args);
736 }
737
738 static bool nbd_clear_req(struct request *req, void *data, bool reserved)
739 {
740 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
741
742 cmd->status = BLK_STS_IOERR;
743 blk_mq_complete_request(req);
744 return true;
745 }
746
747 static void nbd_clear_que(struct nbd_device *nbd)
748 {
749 blk_mq_quiesce_queue(nbd->disk->queue);
750 blk_mq_tagset_busy_iter(&nbd->tag_set, nbd_clear_req, NULL);
751 blk_mq_unquiesce_queue(nbd->disk->queue);
752 dev_dbg(disk_to_dev(nbd->disk), "queue cleared\n");
753 }
754
755 static int find_fallback(struct nbd_device *nbd, int index)
756 {
757 struct nbd_config *config = nbd->config;
758 int new_index = -1;
759 struct nbd_sock *nsock = config->socks[index];
760 int fallback = nsock->fallback_index;
761
762 if (test_bit(NBD_DISCONNECTED, &config->runtime_flags))
763 return new_index;
764
765 if (config->num_connections <= 1) {
766 dev_err_ratelimited(disk_to_dev(nbd->disk),
767 "Attempted send on invalid socket\n");
768 return new_index;
769 }
770
771 if (fallback >= 0 && fallback < config->num_connections &&
772 !config->socks[fallback]->dead)
773 return fallback;
774
775 if (nsock->fallback_index < 0 ||
776 nsock->fallback_index >= config->num_connections ||
777 config->socks[nsock->fallback_index]->dead) {
778 int i;
779 for (i = 0; i < config->num_connections; i++) {
780 if (i == index)
781 continue;
782 if (!config->socks[i]->dead) {
783 new_index = i;
784 break;
785 }
786 }
787 nsock->fallback_index = new_index;
788 if (new_index < 0) {
789 dev_err_ratelimited(disk_to_dev(nbd->disk),
790 "Dead connection, failed to find a fallback\n");
791 return new_index;
792 }
793 }
794 new_index = nsock->fallback_index;
795 return new_index;
796 }
797
798 static int wait_for_reconnect(struct nbd_device *nbd)
799 {
800 struct nbd_config *config = nbd->config;
801 if (!config->dead_conn_timeout)
802 return 0;
803 if (test_bit(NBD_DISCONNECTED, &config->runtime_flags))
804 return 0;
805 return wait_event_timeout(config->conn_wait,
806 atomic_read(&config->live_connections) > 0,
807 config->dead_conn_timeout) > 0;
808 }
809
810 static int nbd_handle_cmd(struct nbd_cmd *cmd, int index)
811 {
812 struct request *req = blk_mq_rq_from_pdu(cmd);
813 struct nbd_device *nbd = cmd->nbd;
814 struct nbd_config *config;
815 struct nbd_sock *nsock;
816 int ret;
817
818 if (!refcount_inc_not_zero(&nbd->config_refs)) {
819 dev_err_ratelimited(disk_to_dev(nbd->disk),
820 "Socks array is empty\n");
821 blk_mq_start_request(req);
822 return -EINVAL;
823 }
824 config = nbd->config;
825
826 if (index >= config->num_connections) {
827 dev_err_ratelimited(disk_to_dev(nbd->disk),
828 "Attempted send on invalid socket\n");
829 nbd_config_put(nbd);
830 blk_mq_start_request(req);
831 return -EINVAL;
832 }
833 cmd->status = BLK_STS_OK;
834 again:
835 nsock = config->socks[index];
836 mutex_lock(&nsock->tx_lock);
837 if (nsock->dead) {
838 int old_index = index;
839 index = find_fallback(nbd, index);
840 mutex_unlock(&nsock->tx_lock);
841 if (index < 0) {
842 if (wait_for_reconnect(nbd)) {
843 index = old_index;
844 goto again;
845 }
846 /* All the sockets should already be down at this point,
847 * we just want to make sure that DISCONNECTED is set so
848 * any requests that come in that were queue'ed waiting
849 * for the reconnect timer don't trigger the timer again
850 * and instead just error out.
851 */
852 sock_shutdown(nbd);
853 nbd_config_put(nbd);
854 blk_mq_start_request(req);
855 return -EIO;
856 }
857 goto again;
858 }
859
860 /* Handle the case that we have a pending request that was partially
861 * transmitted that _has_ to be serviced first. We need to call requeue
862 * here so that it gets put _after_ the request that is already on the
863 * dispatch list.
864 */
865 blk_mq_start_request(req);
866 if (unlikely(nsock->pending && nsock->pending != req)) {
867 nbd_requeue_cmd(cmd);
868 ret = 0;
869 goto out;
870 }
871 /*
872 * Some failures are related to the link going down, so anything that
873 * returns EAGAIN can be retried on a different socket.
874 */
875 ret = nbd_send_cmd(nbd, cmd, index);
876 if (ret == -EAGAIN) {
877 dev_err_ratelimited(disk_to_dev(nbd->disk),
878 "Request send failed, requeueing\n");
879 nbd_mark_nsock_dead(nbd, nsock, 1);
880 nbd_requeue_cmd(cmd);
881 ret = 0;
882 }
883 out:
884 mutex_unlock(&nsock->tx_lock);
885 nbd_config_put(nbd);
886 return ret;
887 }
888
889 static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
890 const struct blk_mq_queue_data *bd)
891 {
892 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
893 int ret;
894
895 /*
896 * Since we look at the bio's to send the request over the network we
897 * need to make sure the completion work doesn't mark this request done
898 * before we are done doing our send. This keeps us from dereferencing
899 * freed data if we have particularly fast completions (ie we get the
900 * completion before we exit sock_xmit on the last bvec) or in the case
901 * that the server is misbehaving (or there was an error) before we're
902 * done sending everything over the wire.
903 */
904 mutex_lock(&cmd->lock);
905 clear_bit(NBD_CMD_REQUEUED, &cmd->flags);
906
907 /* We can be called directly from the user space process, which means we
908 * could possibly have signals pending so our sendmsg will fail. In
909 * this case we need to return that we are busy, otherwise error out as
910 * appropriate.
911 */
912 ret = nbd_handle_cmd(cmd, hctx->queue_num);
913 if (ret < 0)
914 ret = BLK_STS_IOERR;
915 else if (!ret)
916 ret = BLK_STS_OK;
917 mutex_unlock(&cmd->lock);
918
919 return ret;
920 }
921
922 static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
923 bool netlink)
924 {
925 struct nbd_config *config = nbd->config;
926 struct socket *sock;
927 struct nbd_sock **socks;
928 struct nbd_sock *nsock;
929 int err;
930
931 sock = sockfd_lookup(arg, &err);
932 if (!sock)
933 return err;
934
935 if (!netlink && !nbd->task_setup &&
936 !test_bit(NBD_BOUND, &config->runtime_flags))
937 nbd->task_setup = current;
938
939 if (!netlink &&
940 (nbd->task_setup != current ||
941 test_bit(NBD_BOUND, &config->runtime_flags))) {
942 dev_err(disk_to_dev(nbd->disk),
943 "Device being setup by another task");
944 sockfd_put(sock);
945 return -EBUSY;
946 }
947
948 socks = krealloc(config->socks, (config->num_connections + 1) *
949 sizeof(struct nbd_sock *), GFP_KERNEL);
950 if (!socks) {
951 sockfd_put(sock);
952 return -ENOMEM;
953 }
954 nsock = kzalloc(sizeof(struct nbd_sock), GFP_KERNEL);
955 if (!nsock) {
956 sockfd_put(sock);
957 return -ENOMEM;
958 }
959
960 config->socks = socks;
961
962 nsock->fallback_index = -1;
963 nsock->dead = false;
964 mutex_init(&nsock->tx_lock);
965 nsock->sock = sock;
966 nsock->pending = NULL;
967 nsock->sent = 0;
968 nsock->cookie = 0;
969 socks[config->num_connections++] = nsock;
970 atomic_inc(&config->live_connections);
971
972 return 0;
973 }
974
975 static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg)
976 {
977 struct nbd_config *config = nbd->config;
978 struct socket *sock, *old;
979 struct recv_thread_args *args;
980 int i;
981 int err;
982
983 sock = sockfd_lookup(arg, &err);
984 if (!sock)
985 return err;
986
987 args = kzalloc(sizeof(*args), GFP_KERNEL);
988 if (!args) {
989 sockfd_put(sock);
990 return -ENOMEM;
991 }
992
993 for (i = 0; i < config->num_connections; i++) {
994 struct nbd_sock *nsock = config->socks[i];
995
996 if (!nsock->dead)
997 continue;
998
999 mutex_lock(&nsock->tx_lock);
1000 if (!nsock->dead) {
1001 mutex_unlock(&nsock->tx_lock);
1002 continue;
1003 }
1004 sk_set_memalloc(sock->sk);
1005 if (nbd->tag_set.timeout)
1006 sock->sk->sk_sndtimeo = nbd->tag_set.timeout;
1007 atomic_inc(&config->recv_threads);
1008 refcount_inc(&nbd->config_refs);
1009 old = nsock->sock;
1010 nsock->fallback_index = -1;
1011 nsock->sock = sock;
1012 nsock->dead = false;
1013 INIT_WORK(&args->work, recv_work);
1014 args->index = i;
1015 args->nbd = nbd;
1016 nsock->cookie++;
1017 mutex_unlock(&nsock->tx_lock);
1018 sockfd_put(old);
1019
1020 clear_bit(NBD_DISCONNECTED, &config->runtime_flags);
1021
1022 /* We take the tx_mutex in an error path in the recv_work, so we
1023 * need to queue_work outside of the tx_mutex.
1024 */
1025 queue_work(recv_workqueue, &args->work);
1026
1027 atomic_inc(&config->live_connections);
1028 wake_up(&config->conn_wait);
1029 return 0;
1030 }
1031 sockfd_put(sock);
1032 kfree(args);
1033 return -ENOSPC;
1034 }
1035
1036 static void nbd_bdev_reset(struct block_device *bdev)
1037 {
1038 if (bdev->bd_openers > 1)
1039 return;
1040 bd_set_size(bdev, 0);
1041 }
1042
1043 static void nbd_parse_flags(struct nbd_device *nbd)
1044 {
1045 struct nbd_config *config = nbd->config;
1046 if (config->flags & NBD_FLAG_READ_ONLY)
1047 set_disk_ro(nbd->disk, true);
1048 else
1049 set_disk_ro(nbd->disk, false);
1050 if (config->flags & NBD_FLAG_SEND_TRIM)
1051 blk_queue_flag_set(QUEUE_FLAG_DISCARD, nbd->disk->queue);
1052 if (config->flags & NBD_FLAG_SEND_FLUSH) {
1053 if (config->flags & NBD_FLAG_SEND_FUA)
1054 blk_queue_write_cache(nbd->disk->queue, true, true);
1055 else
1056 blk_queue_write_cache(nbd->disk->queue, true, false);
1057 }
1058 else
1059 blk_queue_write_cache(nbd->disk->queue, false, false);
1060 }
1061
1062 static void send_disconnects(struct nbd_device *nbd)
1063 {
1064 struct nbd_config *config = nbd->config;
1065 struct nbd_request request = {
1066 .magic = htonl(NBD_REQUEST_MAGIC),
1067 .type = htonl(NBD_CMD_DISC),
1068 };
1069 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
1070 struct iov_iter from;
1071 int i, ret;
1072
1073 for (i = 0; i < config->num_connections; i++) {
1074 struct nbd_sock *nsock = config->socks[i];
1075
1076 iov_iter_kvec(&from, WRITE, &iov, 1, sizeof(request));
1077 mutex_lock(&nsock->tx_lock);
1078 ret = sock_xmit(nbd, i, 1, &from, 0, NULL);
1079 if (ret <= 0)
1080 dev_err(disk_to_dev(nbd->disk),
1081 "Send disconnect failed %d\n", ret);
1082 mutex_unlock(&nsock->tx_lock);
1083 }
1084 }
1085
1086 static int nbd_disconnect(struct nbd_device *nbd)
1087 {
1088 struct nbd_config *config = nbd->config;
1089
1090 dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
1091 set_bit(NBD_DISCONNECT_REQUESTED, &config->runtime_flags);
1092 send_disconnects(nbd);
1093 return 0;
1094 }
1095
1096 static void nbd_clear_sock(struct nbd_device *nbd)
1097 {
1098 sock_shutdown(nbd);
1099 nbd_clear_que(nbd);
1100 nbd->task_setup = NULL;
1101 }
1102
1103 static void nbd_config_put(struct nbd_device *nbd)
1104 {
1105 if (refcount_dec_and_mutex_lock(&nbd->config_refs,
1106 &nbd->config_lock)) {
1107 struct nbd_config *config = nbd->config;
1108 nbd_dev_dbg_close(nbd);
1109 nbd_size_clear(nbd);
1110 if (test_and_clear_bit(NBD_HAS_PID_FILE,
1111 &config->runtime_flags))
1112 device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
1113 nbd->task_recv = NULL;
1114 nbd_clear_sock(nbd);
1115 if (config->num_connections) {
1116 int i;
1117 for (i = 0; i < config->num_connections; i++) {
1118 sockfd_put(config->socks[i]->sock);
1119 kfree(config->socks[i]);
1120 }
1121 kfree(config->socks);
1122 }
1123 kfree(nbd->config);
1124 nbd->config = NULL;
1125
1126 nbd->tag_set.timeout = 0;
1127 nbd->disk->queue->limits.discard_granularity = 0;
1128 nbd->disk->queue->limits.discard_alignment = 0;
1129 blk_queue_max_discard_sectors(nbd->disk->queue, UINT_MAX);
1130 blk_queue_flag_clear(QUEUE_FLAG_DISCARD, nbd->disk->queue);
1131
1132 mutex_unlock(&nbd->config_lock);
1133 nbd_put(nbd);
1134 module_put(THIS_MODULE);
1135 }
1136 }
1137
1138 static int nbd_start_device(struct nbd_device *nbd)
1139 {
1140 struct nbd_config *config = nbd->config;
1141 int num_connections = config->num_connections;
1142 int error = 0, i;
1143
1144 if (nbd->task_recv)
1145 return -EBUSY;
1146 if (!config->socks)
1147 return -EINVAL;
1148 if (num_connections > 1 &&
1149 !(config->flags & NBD_FLAG_CAN_MULTI_CONN)) {
1150 dev_err(disk_to_dev(nbd->disk), "server does not support multiple connections per device.\n");
1151 return -EINVAL;
1152 }
1153
1154 blk_mq_update_nr_hw_queues(&nbd->tag_set, config->num_connections);
1155 nbd->task_recv = current;
1156
1157 nbd_parse_flags(nbd);
1158
1159 error = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
1160 if (error) {
1161 dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n");
1162 return error;
1163 }
1164 set_bit(NBD_HAS_PID_FILE, &config->runtime_flags);
1165
1166 nbd_dev_dbg_init(nbd);
1167 for (i = 0; i < num_connections; i++) {
1168 struct recv_thread_args *args;
1169
1170 args = kzalloc(sizeof(*args), GFP_KERNEL);
1171 if (!args) {
1172 sock_shutdown(nbd);
1173 return -ENOMEM;
1174 }
1175 sk_set_memalloc(config->socks[i]->sock->sk);
1176 if (nbd->tag_set.timeout)
1177 config->socks[i]->sock->sk->sk_sndtimeo =
1178 nbd->tag_set.timeout;
1179 atomic_inc(&config->recv_threads);
1180 refcount_inc(&nbd->config_refs);
1181 INIT_WORK(&args->work, recv_work);
1182 args->nbd = nbd;
1183 args->index = i;
1184 queue_work(recv_workqueue, &args->work);
1185 }
1186 nbd_size_update(nbd);
1187 return error;
1188 }
1189
1190 static int nbd_start_device_ioctl(struct nbd_device *nbd, struct block_device *bdev)
1191 {
1192 struct nbd_config *config = nbd->config;
1193 int ret;
1194
1195 ret = nbd_start_device(nbd);
1196 if (ret)
1197 return ret;
1198
1199 if (max_part)
1200 bdev->bd_invalidated = 1;
1201 mutex_unlock(&nbd->config_lock);
1202 ret = wait_event_interruptible(config->recv_wq,
1203 atomic_read(&config->recv_threads) == 0);
1204 if (ret)
1205 sock_shutdown(nbd);
1206 mutex_lock(&nbd->config_lock);
1207 nbd_bdev_reset(bdev);
1208 /* user requested, ignore socket errors */
1209 if (test_bit(NBD_DISCONNECT_REQUESTED, &config->runtime_flags))
1210 ret = 0;
1211 if (test_bit(NBD_TIMEDOUT, &config->runtime_flags))
1212 ret = -ETIMEDOUT;
1213 return ret;
1214 }
1215
1216 static void nbd_clear_sock_ioctl(struct nbd_device *nbd,
1217 struct block_device *bdev)
1218 {
1219 sock_shutdown(nbd);
1220 kill_bdev(bdev);
1221 nbd_bdev_reset(bdev);
1222 if (test_and_clear_bit(NBD_HAS_CONFIG_REF,
1223 &nbd->config->runtime_flags))
1224 nbd_config_put(nbd);
1225 }
1226
1227 /* Must be called with config_lock held */
1228 static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
1229 unsigned int cmd, unsigned long arg)
1230 {
1231 struct nbd_config *config = nbd->config;
1232
1233 switch (cmd) {
1234 case NBD_DISCONNECT:
1235 return nbd_disconnect(nbd);
1236 case NBD_CLEAR_SOCK:
1237 nbd_clear_sock_ioctl(nbd, bdev);
1238 return 0;
1239 case NBD_SET_SOCK:
1240 return nbd_add_socket(nbd, arg, false);
1241 case NBD_SET_BLKSIZE:
1242 if (!arg || !is_power_of_2(arg) || arg < 512 ||
1243 arg > PAGE_SIZE)
1244 return -EINVAL;
1245 nbd_size_set(nbd, arg,
1246 div_s64(config->bytesize, arg));
1247 return 0;
1248 case NBD_SET_SIZE:
1249 nbd_size_set(nbd, config->blksize,
1250 div_s64(arg, config->blksize));
1251 return 0;
1252 case NBD_SET_SIZE_BLOCKS:
1253 nbd_size_set(nbd, config->blksize, arg);
1254 return 0;
1255 case NBD_SET_TIMEOUT:
1256 if (arg) {
1257 nbd->tag_set.timeout = arg * HZ;
1258 blk_queue_rq_timeout(nbd->disk->queue, arg * HZ);
1259 }
1260 return 0;
1261
1262 case NBD_SET_FLAGS:
1263 config->flags = arg;
1264 return 0;
1265 case NBD_DO_IT:
1266 return nbd_start_device_ioctl(nbd, bdev);
1267 case NBD_CLEAR_QUE:
1268 /*
1269 * This is for compatibility only. The queue is always cleared
1270 * by NBD_DO_IT or NBD_CLEAR_SOCK.
1271 */
1272 return 0;
1273 case NBD_PRINT_DEBUG:
1274 /*
1275 * For compatibility only, we no longer keep a list of
1276 * outstanding requests.
1277 */
1278 return 0;
1279 }
1280 return -ENOTTY;
1281 }
1282
1283 static int nbd_ioctl(struct block_device *bdev, fmode_t mode,
1284 unsigned int cmd, unsigned long arg)
1285 {
1286 struct nbd_device *nbd = bdev->bd_disk->private_data;
1287 struct nbd_config *config = nbd->config;
1288 int error = -EINVAL;
1289
1290 if (!capable(CAP_SYS_ADMIN))
1291 return -EPERM;
1292
1293 /* The block layer will pass back some non-nbd ioctls in case we have
1294 * special handling for them, but we don't so just return an error.
1295 */
1296 if (_IOC_TYPE(cmd) != 0xab)
1297 return -EINVAL;
1298
1299 mutex_lock(&nbd->config_lock);
1300
1301 /* Don't allow ioctl operations on a nbd device that was created with
1302 * netlink, unless it's DISCONNECT or CLEAR_SOCK, which are fine.
1303 */
1304 if (!test_bit(NBD_BOUND, &config->runtime_flags) ||
1305 (cmd == NBD_DISCONNECT || cmd == NBD_CLEAR_SOCK))
1306 error = __nbd_ioctl(bdev, nbd, cmd, arg);
1307 else
1308 dev_err(nbd_to_dev(nbd), "Cannot use ioctl interface on a netlink controlled device.\n");
1309 mutex_unlock(&nbd->config_lock);
1310 return error;
1311 }
1312
1313 static struct nbd_config *nbd_alloc_config(void)
1314 {
1315 struct nbd_config *config;
1316
1317 config = kzalloc(sizeof(struct nbd_config), GFP_NOFS);
1318 if (!config)
1319 return NULL;
1320 atomic_set(&config->recv_threads, 0);
1321 init_waitqueue_head(&config->recv_wq);
1322 init_waitqueue_head(&config->conn_wait);
1323 config->blksize = 1024;
1324 atomic_set(&config->live_connections, 0);
1325 try_module_get(THIS_MODULE);
1326 return config;
1327 }
1328
1329 static int nbd_open(struct block_device *bdev, fmode_t mode)
1330 {
1331 struct nbd_device *nbd;
1332 int ret = 0;
1333
1334 mutex_lock(&nbd_index_mutex);
1335 nbd = bdev->bd_disk->private_data;
1336 if (!nbd) {
1337 ret = -ENXIO;
1338 goto out;
1339 }
1340 if (!refcount_inc_not_zero(&nbd->refs)) {
1341 ret = -ENXIO;
1342 goto out;
1343 }
1344 if (!refcount_inc_not_zero(&nbd->config_refs)) {
1345 struct nbd_config *config;
1346
1347 mutex_lock(&nbd->config_lock);
1348 if (refcount_inc_not_zero(&nbd->config_refs)) {
1349 mutex_unlock(&nbd->config_lock);
1350 goto out;
1351 }
1352 config = nbd->config = nbd_alloc_config();
1353 if (!config) {
1354 ret = -ENOMEM;
1355 mutex_unlock(&nbd->config_lock);
1356 goto out;
1357 }
1358 refcount_set(&nbd->config_refs, 1);
1359 refcount_inc(&nbd->refs);
1360 mutex_unlock(&nbd->config_lock);
1361 bdev->bd_invalidated = 1;
1362 } else if (nbd_disconnected(nbd->config)) {
1363 bdev->bd_invalidated = 1;
1364 }
1365 out:
1366 mutex_unlock(&nbd_index_mutex);
1367 return ret;
1368 }
1369
1370 static void nbd_release(struct gendisk *disk, fmode_t mode)
1371 {
1372 struct nbd_device *nbd = disk->private_data;
1373 struct block_device *bdev = bdget_disk(disk, 0);
1374
1375 if (test_bit(NBD_DISCONNECT_ON_CLOSE, &nbd->config->runtime_flags) &&
1376 bdev->bd_openers == 0)
1377 nbd_disconnect_and_put(nbd);
1378
1379 nbd_config_put(nbd);
1380 nbd_put(nbd);
1381 }
1382
1383 static const struct block_device_operations nbd_fops =
1384 {
1385 .owner = THIS_MODULE,
1386 .open = nbd_open,
1387 .release = nbd_release,
1388 .ioctl = nbd_ioctl,
1389 .compat_ioctl = nbd_ioctl,
1390 };
1391
1392 #if IS_ENABLED(CONFIG_DEBUG_FS)
1393
1394 static int nbd_dbg_tasks_show(struct seq_file *s, void *unused)
1395 {
1396 struct nbd_device *nbd = s->private;
1397
1398 if (nbd->task_recv)
1399 seq_printf(s, "recv: %d\n", task_pid_nr(nbd->task_recv));
1400
1401 return 0;
1402 }
1403
1404 static int nbd_dbg_tasks_open(struct inode *inode, struct file *file)
1405 {
1406 return single_open(file, nbd_dbg_tasks_show, inode->i_private);
1407 }
1408
1409 static const struct file_operations nbd_dbg_tasks_ops = {
1410 .open = nbd_dbg_tasks_open,
1411 .read = seq_read,
1412 .llseek = seq_lseek,
1413 .release = single_release,
1414 };
1415
1416 static int nbd_dbg_flags_show(struct seq_file *s, void *unused)
1417 {
1418 struct nbd_device *nbd = s->private;
1419 u32 flags = nbd->config->flags;
1420
1421 seq_printf(s, "Hex: 0x%08x\n\n", flags);
1422
1423 seq_puts(s, "Known flags:\n");
1424
1425 if (flags & NBD_FLAG_HAS_FLAGS)
1426 seq_puts(s, "NBD_FLAG_HAS_FLAGS\n");
1427 if (flags & NBD_FLAG_READ_ONLY)
1428 seq_puts(s, "NBD_FLAG_READ_ONLY\n");
1429 if (flags & NBD_FLAG_SEND_FLUSH)
1430 seq_puts(s, "NBD_FLAG_SEND_FLUSH\n");
1431 if (flags & NBD_FLAG_SEND_FUA)
1432 seq_puts(s, "NBD_FLAG_SEND_FUA\n");
1433 if (flags & NBD_FLAG_SEND_TRIM)
1434 seq_puts(s, "NBD_FLAG_SEND_TRIM\n");
1435
1436 return 0;
1437 }
1438
1439 static int nbd_dbg_flags_open(struct inode *inode, struct file *file)
1440 {
1441 return single_open(file, nbd_dbg_flags_show, inode->i_private);
1442 }
1443
1444 static const struct file_operations nbd_dbg_flags_ops = {
1445 .open = nbd_dbg_flags_open,
1446 .read = seq_read,
1447 .llseek = seq_lseek,
1448 .release = single_release,
1449 };
1450
1451 static int nbd_dev_dbg_init(struct nbd_device *nbd)
1452 {
1453 struct dentry *dir;
1454 struct nbd_config *config = nbd->config;
1455
1456 if (!nbd_dbg_dir)
1457 return -EIO;
1458
1459 dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir);
1460 if (!dir) {
1461 dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s'\n",
1462 nbd_name(nbd));
1463 return -EIO;
1464 }
1465 config->dbg_dir = dir;
1466
1467 debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_ops);
1468 debugfs_create_u64("size_bytes", 0444, dir, &config->bytesize);
1469 debugfs_create_u32("timeout", 0444, dir, &nbd->tag_set.timeout);
1470 debugfs_create_u64("blocksize", 0444, dir, &config->blksize);
1471 debugfs_create_file("flags", 0444, dir, nbd, &nbd_dbg_flags_ops);
1472
1473 return 0;
1474 }
1475
1476 static void nbd_dev_dbg_close(struct nbd_device *nbd)
1477 {
1478 debugfs_remove_recursive(nbd->config->dbg_dir);
1479 }
1480
1481 static int nbd_dbg_init(void)
1482 {
1483 struct dentry *dbg_dir;
1484
1485 dbg_dir = debugfs_create_dir("nbd", NULL);
1486 if (!dbg_dir)
1487 return -EIO;
1488
1489 nbd_dbg_dir = dbg_dir;
1490
1491 return 0;
1492 }
1493
1494 static void nbd_dbg_close(void)
1495 {
1496 debugfs_remove_recursive(nbd_dbg_dir);
1497 }
1498
1499 #else /* IS_ENABLED(CONFIG_DEBUG_FS) */
1500
1501 static int nbd_dev_dbg_init(struct nbd_device *nbd)
1502 {
1503 return 0;
1504 }
1505
1506 static void nbd_dev_dbg_close(struct nbd_device *nbd)
1507 {
1508 }
1509
1510 static int nbd_dbg_init(void)
1511 {
1512 return 0;
1513 }
1514
1515 static void nbd_dbg_close(void)
1516 {
1517 }
1518
1519 #endif
1520
1521 static int nbd_init_request(struct blk_mq_tag_set *set, struct request *rq,
1522 unsigned int hctx_idx, unsigned int numa_node)
1523 {
1524 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq);
1525 cmd->nbd = set->driver_data;
1526 cmd->flags = 0;
1527 mutex_init(&cmd->lock);
1528 return 0;
1529 }
1530
1531 static const struct blk_mq_ops nbd_mq_ops = {
1532 .queue_rq = nbd_queue_rq,
1533 .complete = nbd_complete_rq,
1534 .init_request = nbd_init_request,
1535 .timeout = nbd_xmit_timeout,
1536 };
1537
1538 static int nbd_dev_add(int index)
1539 {
1540 struct nbd_device *nbd;
1541 struct gendisk *disk;
1542 struct request_queue *q;
1543 int err = -ENOMEM;
1544
1545 nbd = kzalloc(sizeof(struct nbd_device), GFP_KERNEL);
1546 if (!nbd)
1547 goto out;
1548
1549 disk = alloc_disk(1 << part_shift);
1550 if (!disk)
1551 goto out_free_nbd;
1552
1553 if (index >= 0) {
1554 err = idr_alloc(&nbd_index_idr, nbd, index, index + 1,
1555 GFP_KERNEL);
1556 if (err == -ENOSPC)
1557 err = -EEXIST;
1558 } else {
1559 err = idr_alloc(&nbd_index_idr, nbd, 0, 0, GFP_KERNEL);
1560 if (err >= 0)
1561 index = err;
1562 }
1563 if (err < 0)
1564 goto out_free_disk;
1565
1566 nbd->index = index;
1567 nbd->disk = disk;
1568 nbd->tag_set.ops = &nbd_mq_ops;
1569 nbd->tag_set.nr_hw_queues = 1;
1570 nbd->tag_set.queue_depth = 128;
1571 nbd->tag_set.numa_node = NUMA_NO_NODE;
1572 nbd->tag_set.cmd_size = sizeof(struct nbd_cmd);
1573 nbd->tag_set.flags = BLK_MQ_F_SHOULD_MERGE |
1574 BLK_MQ_F_BLOCKING;
1575 nbd->tag_set.driver_data = nbd;
1576
1577 err = blk_mq_alloc_tag_set(&nbd->tag_set);
1578 if (err)
1579 goto out_free_idr;
1580
1581 q = blk_mq_init_queue(&nbd->tag_set);
1582 if (IS_ERR(q)) {
1583 err = PTR_ERR(q);
1584 goto out_free_tags;
1585 }
1586 disk->queue = q;
1587
1588 /*
1589 * Tell the block layer that we are not a rotational device
1590 */
1591 blk_queue_flag_set(QUEUE_FLAG_NONROT, disk->queue);
1592 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, disk->queue);
1593 disk->queue->limits.discard_granularity = 0;
1594 disk->queue->limits.discard_alignment = 0;
1595 blk_queue_max_discard_sectors(disk->queue, 0);
1596 blk_queue_max_segment_size(disk->queue, UINT_MAX);
1597 blk_queue_max_segments(disk->queue, USHRT_MAX);
1598 blk_queue_max_hw_sectors(disk->queue, 65536);
1599 disk->queue->limits.max_sectors = 256;
1600
1601 mutex_init(&nbd->config_lock);
1602 refcount_set(&nbd->config_refs, 0);
1603 refcount_set(&nbd->refs, 1);
1604 INIT_LIST_HEAD(&nbd->list);
1605 disk->major = NBD_MAJOR;
1606 disk->first_minor = index << part_shift;
1607 disk->fops = &nbd_fops;
1608 disk->private_data = nbd;
1609 sprintf(disk->disk_name, "nbd%d", index);
1610 add_disk(disk);
1611 nbd_total_devices++;
1612 return index;
1613
1614 out_free_tags:
1615 blk_mq_free_tag_set(&nbd->tag_set);
1616 out_free_idr:
1617 idr_remove(&nbd_index_idr, index);
1618 out_free_disk:
1619 put_disk(disk);
1620 out_free_nbd:
1621 kfree(nbd);
1622 out:
1623 return err;
1624 }
1625
1626 static int find_free_cb(int id, void *ptr, void *data)
1627 {
1628 struct nbd_device *nbd = ptr;
1629 struct nbd_device **found = data;
1630
1631 if (!refcount_read(&nbd->config_refs)) {
1632 *found = nbd;
1633 return 1;
1634 }
1635 return 0;
1636 }
1637
1638 /* Netlink interface. */
1639 static const struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = {
1640 [NBD_ATTR_INDEX] = { .type = NLA_U32 },
1641 [NBD_ATTR_SIZE_BYTES] = { .type = NLA_U64 },
1642 [NBD_ATTR_BLOCK_SIZE_BYTES] = { .type = NLA_U64 },
1643 [NBD_ATTR_TIMEOUT] = { .type = NLA_U64 },
1644 [NBD_ATTR_SERVER_FLAGS] = { .type = NLA_U64 },
1645 [NBD_ATTR_CLIENT_FLAGS] = { .type = NLA_U64 },
1646 [NBD_ATTR_SOCKETS] = { .type = NLA_NESTED},
1647 [NBD_ATTR_DEAD_CONN_TIMEOUT] = { .type = NLA_U64 },
1648 [NBD_ATTR_DEVICE_LIST] = { .type = NLA_NESTED},
1649 };
1650
1651 static const struct nla_policy nbd_sock_policy[NBD_SOCK_MAX + 1] = {
1652 [NBD_SOCK_FD] = { .type = NLA_U32 },
1653 };
1654
1655 /* We don't use this right now since we don't parse the incoming list, but we
1656 * still want it here so userspace knows what to expect.
1657 */
1658 static const struct nla_policy __attribute__((unused))
1659 nbd_device_policy[NBD_DEVICE_ATTR_MAX + 1] = {
1660 [NBD_DEVICE_INDEX] = { .type = NLA_U32 },
1661 [NBD_DEVICE_CONNECTED] = { .type = NLA_U8 },
1662 };
1663
1664 static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
1665 {
1666 struct nbd_device *nbd = NULL;
1667 struct nbd_config *config;
1668 int index = -1;
1669 int ret;
1670 bool put_dev = false;
1671
1672 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1673 return -EPERM;
1674
1675 if (info->attrs[NBD_ATTR_INDEX])
1676 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1677 if (!info->attrs[NBD_ATTR_SOCKETS]) {
1678 printk(KERN_ERR "nbd: must specify at least one socket\n");
1679 return -EINVAL;
1680 }
1681 if (!info->attrs[NBD_ATTR_SIZE_BYTES]) {
1682 printk(KERN_ERR "nbd: must specify a size in bytes for the device\n");
1683 return -EINVAL;
1684 }
1685 again:
1686 mutex_lock(&nbd_index_mutex);
1687 if (index == -1) {
1688 ret = idr_for_each(&nbd_index_idr, &find_free_cb, &nbd);
1689 if (ret == 0) {
1690 int new_index;
1691 new_index = nbd_dev_add(-1);
1692 if (new_index < 0) {
1693 mutex_unlock(&nbd_index_mutex);
1694 printk(KERN_ERR "nbd: failed to add new device\n");
1695 return new_index;
1696 }
1697 nbd = idr_find(&nbd_index_idr, new_index);
1698 }
1699 } else {
1700 nbd = idr_find(&nbd_index_idr, index);
1701 if (!nbd) {
1702 ret = nbd_dev_add(index);
1703 if (ret < 0) {
1704 mutex_unlock(&nbd_index_mutex);
1705 printk(KERN_ERR "nbd: failed to add new device\n");
1706 return ret;
1707 }
1708 nbd = idr_find(&nbd_index_idr, index);
1709 }
1710 }
1711 if (!nbd) {
1712 printk(KERN_ERR "nbd: couldn't find device at index %d\n",
1713 index);
1714 mutex_unlock(&nbd_index_mutex);
1715 return -EINVAL;
1716 }
1717 if (!refcount_inc_not_zero(&nbd->refs)) {
1718 mutex_unlock(&nbd_index_mutex);
1719 if (index == -1)
1720 goto again;
1721 printk(KERN_ERR "nbd: device at index %d is going down\n",
1722 index);
1723 return -EINVAL;
1724 }
1725 mutex_unlock(&nbd_index_mutex);
1726
1727 mutex_lock(&nbd->config_lock);
1728 if (refcount_read(&nbd->config_refs)) {
1729 mutex_unlock(&nbd->config_lock);
1730 nbd_put(nbd);
1731 if (index == -1)
1732 goto again;
1733 printk(KERN_ERR "nbd: nbd%d already in use\n", index);
1734 return -EBUSY;
1735 }
1736 if (WARN_ON(nbd->config)) {
1737 mutex_unlock(&nbd->config_lock);
1738 nbd_put(nbd);
1739 return -EINVAL;
1740 }
1741 config = nbd->config = nbd_alloc_config();
1742 if (!nbd->config) {
1743 mutex_unlock(&nbd->config_lock);
1744 nbd_put(nbd);
1745 printk(KERN_ERR "nbd: couldn't allocate config\n");
1746 return -ENOMEM;
1747 }
1748 refcount_set(&nbd->config_refs, 1);
1749 set_bit(NBD_BOUND, &config->runtime_flags);
1750
1751 if (info->attrs[NBD_ATTR_SIZE_BYTES]) {
1752 u64 bytes = nla_get_u64(info->attrs[NBD_ATTR_SIZE_BYTES]);
1753 nbd_size_set(nbd, config->blksize,
1754 div64_u64(bytes, config->blksize));
1755 }
1756 if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]) {
1757 u64 bsize =
1758 nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]);
1759 nbd_size_set(nbd, bsize, div64_u64(config->bytesize, bsize));
1760 }
1761 if (info->attrs[NBD_ATTR_TIMEOUT]) {
1762 u64 timeout = nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]);
1763 nbd->tag_set.timeout = timeout * HZ;
1764 blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ);
1765 }
1766 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
1767 config->dead_conn_timeout =
1768 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
1769 config->dead_conn_timeout *= HZ;
1770 }
1771 if (info->attrs[NBD_ATTR_SERVER_FLAGS])
1772 config->flags =
1773 nla_get_u64(info->attrs[NBD_ATTR_SERVER_FLAGS]);
1774 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
1775 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
1776 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
1777 set_bit(NBD_DESTROY_ON_DISCONNECT,
1778 &config->runtime_flags);
1779 put_dev = true;
1780 }
1781 if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {
1782 set_bit(NBD_DISCONNECT_ON_CLOSE,
1783 &config->runtime_flags);
1784 }
1785 }
1786
1787 if (info->attrs[NBD_ATTR_SOCKETS]) {
1788 struct nlattr *attr;
1789 int rem, fd;
1790
1791 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
1792 rem) {
1793 struct nlattr *socks[NBD_SOCK_MAX+1];
1794
1795 if (nla_type(attr) != NBD_SOCK_ITEM) {
1796 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");
1797 ret = -EINVAL;
1798 goto out;
1799 }
1800 ret = nla_parse_nested(socks, NBD_SOCK_MAX, attr,
1801 nbd_sock_policy, info->extack);
1802 if (ret != 0) {
1803 printk(KERN_ERR "nbd: error processing sock list\n");
1804 ret = -EINVAL;
1805 goto out;
1806 }
1807 if (!socks[NBD_SOCK_FD])
1808 continue;
1809 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
1810 ret = nbd_add_socket(nbd, fd, true);
1811 if (ret)
1812 goto out;
1813 }
1814 }
1815 ret = nbd_start_device(nbd);
1816 out:
1817 mutex_unlock(&nbd->config_lock);
1818 if (!ret) {
1819 set_bit(NBD_HAS_CONFIG_REF, &config->runtime_flags);
1820 refcount_inc(&nbd->config_refs);
1821 nbd_connect_reply(info, nbd->index);
1822 }
1823 nbd_config_put(nbd);
1824 if (put_dev)
1825 nbd_put(nbd);
1826 return ret;
1827 }
1828
1829 static void nbd_disconnect_and_put(struct nbd_device *nbd)
1830 {
1831 mutex_lock(&nbd->config_lock);
1832 nbd_disconnect(nbd);
1833 nbd_clear_sock(nbd);
1834 mutex_unlock(&nbd->config_lock);
1835 if (test_and_clear_bit(NBD_HAS_CONFIG_REF,
1836 &nbd->config->runtime_flags))
1837 nbd_config_put(nbd);
1838 }
1839
1840 static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info)
1841 {
1842 struct nbd_device *nbd;
1843 int index;
1844
1845 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1846 return -EPERM;
1847
1848 if (!info->attrs[NBD_ATTR_INDEX]) {
1849 printk(KERN_ERR "nbd: must specify an index to disconnect\n");
1850 return -EINVAL;
1851 }
1852 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1853 mutex_lock(&nbd_index_mutex);
1854 nbd = idr_find(&nbd_index_idr, index);
1855 if (!nbd) {
1856 mutex_unlock(&nbd_index_mutex);
1857 printk(KERN_ERR "nbd: couldn't find device at index %d\n",
1858 index);
1859 return -EINVAL;
1860 }
1861 if (!refcount_inc_not_zero(&nbd->refs)) {
1862 mutex_unlock(&nbd_index_mutex);
1863 printk(KERN_ERR "nbd: device at index %d is going down\n",
1864 index);
1865 return -EINVAL;
1866 }
1867 mutex_unlock(&nbd_index_mutex);
1868 if (!refcount_inc_not_zero(&nbd->config_refs)) {
1869 nbd_put(nbd);
1870 return 0;
1871 }
1872 nbd_disconnect_and_put(nbd);
1873 nbd_config_put(nbd);
1874 nbd_put(nbd);
1875 return 0;
1876 }
1877
1878 static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info)
1879 {
1880 struct nbd_device *nbd = NULL;
1881 struct nbd_config *config;
1882 int index;
1883 int ret = 0;
1884 bool put_dev = false;
1885
1886 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1887 return -EPERM;
1888
1889 if (!info->attrs[NBD_ATTR_INDEX]) {
1890 printk(KERN_ERR "nbd: must specify a device to reconfigure\n");
1891 return -EINVAL;
1892 }
1893 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1894 mutex_lock(&nbd_index_mutex);
1895 nbd = idr_find(&nbd_index_idr, index);
1896 if (!nbd) {
1897 mutex_unlock(&nbd_index_mutex);
1898 printk(KERN_ERR "nbd: couldn't find a device at index %d\n",
1899 index);
1900 return -EINVAL;
1901 }
1902 if (!refcount_inc_not_zero(&nbd->refs)) {
1903 mutex_unlock(&nbd_index_mutex);
1904 printk(KERN_ERR "nbd: device at index %d is going down\n",
1905 index);
1906 return -EINVAL;
1907 }
1908 mutex_unlock(&nbd_index_mutex);
1909
1910 if (!refcount_inc_not_zero(&nbd->config_refs)) {
1911 dev_err(nbd_to_dev(nbd),
1912 "not configured, cannot reconfigure\n");
1913 nbd_put(nbd);
1914 return -EINVAL;
1915 }
1916
1917 mutex_lock(&nbd->config_lock);
1918 config = nbd->config;
1919 if (!test_bit(NBD_BOUND, &config->runtime_flags) ||
1920 !nbd->task_recv) {
1921 dev_err(nbd_to_dev(nbd),
1922 "not configured, cannot reconfigure\n");
1923 ret = -EINVAL;
1924 goto out;
1925 }
1926
1927 if (info->attrs[NBD_ATTR_TIMEOUT]) {
1928 u64 timeout = nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]);
1929 nbd->tag_set.timeout = timeout * HZ;
1930 blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ);
1931 }
1932 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
1933 config->dead_conn_timeout =
1934 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
1935 config->dead_conn_timeout *= HZ;
1936 }
1937 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
1938 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
1939 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
1940 if (!test_and_set_bit(NBD_DESTROY_ON_DISCONNECT,
1941 &config->runtime_flags))
1942 put_dev = true;
1943 } else {
1944 if (test_and_clear_bit(NBD_DESTROY_ON_DISCONNECT,
1945 &config->runtime_flags))
1946 refcount_inc(&nbd->refs);
1947 }
1948
1949 if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {
1950 set_bit(NBD_DISCONNECT_ON_CLOSE,
1951 &config->runtime_flags);
1952 } else {
1953 clear_bit(NBD_DISCONNECT_ON_CLOSE,
1954 &config->runtime_flags);
1955 }
1956 }
1957
1958 if (info->attrs[NBD_ATTR_SOCKETS]) {
1959 struct nlattr *attr;
1960 int rem, fd;
1961
1962 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
1963 rem) {
1964 struct nlattr *socks[NBD_SOCK_MAX+1];
1965
1966 if (nla_type(attr) != NBD_SOCK_ITEM) {
1967 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");
1968 ret = -EINVAL;
1969 goto out;
1970 }
1971 ret = nla_parse_nested(socks, NBD_SOCK_MAX, attr,
1972 nbd_sock_policy, info->extack);
1973 if (ret != 0) {
1974 printk(KERN_ERR "nbd: error processing sock list\n");
1975 ret = -EINVAL;
1976 goto out;
1977 }
1978 if (!socks[NBD_SOCK_FD])
1979 continue;
1980 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
1981 ret = nbd_reconnect_socket(nbd, fd);
1982 if (ret) {
1983 if (ret == -ENOSPC)
1984 ret = 0;
1985 goto out;
1986 }
1987 dev_info(nbd_to_dev(nbd), "reconnected socket\n");
1988 }
1989 }
1990 out:
1991 mutex_unlock(&nbd->config_lock);
1992 nbd_config_put(nbd);
1993 nbd_put(nbd);
1994 if (put_dev)
1995 nbd_put(nbd);
1996 return ret;
1997 }
1998
1999 static const struct genl_ops nbd_connect_genl_ops[] = {
2000 {
2001 .cmd = NBD_CMD_CONNECT,
2002 .doit = nbd_genl_connect,
2003 },
2004 {
2005 .cmd = NBD_CMD_DISCONNECT,
2006 .doit = nbd_genl_disconnect,
2007 },
2008 {
2009 .cmd = NBD_CMD_RECONFIGURE,
2010 .doit = nbd_genl_reconfigure,
2011 },
2012 {
2013 .cmd = NBD_CMD_STATUS,
2014 .doit = nbd_genl_status,
2015 },
2016 };
2017
2018 static const struct genl_multicast_group nbd_mcast_grps[] = {
2019 { .name = NBD_GENL_MCAST_GROUP_NAME, },
2020 };
2021
2022 static struct genl_family nbd_genl_family __ro_after_init = {
2023 .hdrsize = 0,
2024 .name = NBD_GENL_FAMILY_NAME,
2025 .version = NBD_GENL_VERSION,
2026 .module = THIS_MODULE,
2027 .ops = nbd_connect_genl_ops,
2028 .n_ops = ARRAY_SIZE(nbd_connect_genl_ops),
2029 .maxattr = NBD_ATTR_MAX,
2030 .policy = nbd_attr_policy,
2031 .mcgrps = nbd_mcast_grps,
2032 .n_mcgrps = ARRAY_SIZE(nbd_mcast_grps),
2033 };
2034
2035 static int populate_nbd_status(struct nbd_device *nbd, struct sk_buff *reply)
2036 {
2037 struct nlattr *dev_opt;
2038 u8 connected = 0;
2039 int ret;
2040
2041 /* This is a little racey, but for status it's ok. The
2042 * reason we don't take a ref here is because we can't
2043 * take a ref in the index == -1 case as we would need
2044 * to put under the nbd_index_mutex, which could
2045 * deadlock if we are configured to remove ourselves
2046 * once we're disconnected.
2047 */
2048 if (refcount_read(&nbd->config_refs))
2049 connected = 1;
2050 dev_opt = nla_nest_start(reply, NBD_DEVICE_ITEM);
2051 if (!dev_opt)
2052 return -EMSGSIZE;
2053 ret = nla_put_u32(reply, NBD_DEVICE_INDEX, nbd->index);
2054 if (ret)
2055 return -EMSGSIZE;
2056 ret = nla_put_u8(reply, NBD_DEVICE_CONNECTED,
2057 connected);
2058 if (ret)
2059 return -EMSGSIZE;
2060 nla_nest_end(reply, dev_opt);
2061 return 0;
2062 }
2063
2064 static int status_cb(int id, void *ptr, void *data)
2065 {
2066 struct nbd_device *nbd = ptr;
2067 return populate_nbd_status(nbd, (struct sk_buff *)data);
2068 }
2069
2070 static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info)
2071 {
2072 struct nlattr *dev_list;
2073 struct sk_buff *reply;
2074 void *reply_head;
2075 size_t msg_size;
2076 int index = -1;
2077 int ret = -ENOMEM;
2078
2079 if (info->attrs[NBD_ATTR_INDEX])
2080 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2081
2082 mutex_lock(&nbd_index_mutex);
2083
2084 msg_size = nla_total_size(nla_attr_size(sizeof(u32)) +
2085 nla_attr_size(sizeof(u8)));
2086 msg_size *= (index == -1) ? nbd_total_devices : 1;
2087
2088 reply = genlmsg_new(msg_size, GFP_KERNEL);
2089 if (!reply)
2090 goto out;
2091 reply_head = genlmsg_put_reply(reply, info, &nbd_genl_family, 0,
2092 NBD_CMD_STATUS);
2093 if (!reply_head) {
2094 nlmsg_free(reply);
2095 goto out;
2096 }
2097
2098 dev_list = nla_nest_start(reply, NBD_ATTR_DEVICE_LIST);
2099 if (index == -1) {
2100 ret = idr_for_each(&nbd_index_idr, &status_cb, reply);
2101 if (ret) {
2102 nlmsg_free(reply);
2103 goto out;
2104 }
2105 } else {
2106 struct nbd_device *nbd;
2107 nbd = idr_find(&nbd_index_idr, index);
2108 if (nbd) {
2109 ret = populate_nbd_status(nbd, reply);
2110 if (ret) {
2111 nlmsg_free(reply);
2112 goto out;
2113 }
2114 }
2115 }
2116 nla_nest_end(reply, dev_list);
2117 genlmsg_end(reply, reply_head);
2118 ret = genlmsg_reply(reply, info);
2119 out:
2120 mutex_unlock(&nbd_index_mutex);
2121 return ret;
2122 }
2123
2124 static void nbd_connect_reply(struct genl_info *info, int index)
2125 {
2126 struct sk_buff *skb;
2127 void *msg_head;
2128 int ret;
2129
2130 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2131 if (!skb)
2132 return;
2133 msg_head = genlmsg_put_reply(skb, info, &nbd_genl_family, 0,
2134 NBD_CMD_CONNECT);
2135 if (!msg_head) {
2136 nlmsg_free(skb);
2137 return;
2138 }
2139 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2140 if (ret) {
2141 nlmsg_free(skb);
2142 return;
2143 }
2144 genlmsg_end(skb, msg_head);
2145 genlmsg_reply(skb, info);
2146 }
2147
2148 static void nbd_mcast_index(int index)
2149 {
2150 struct sk_buff *skb;
2151 void *msg_head;
2152 int ret;
2153
2154 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2155 if (!skb)
2156 return;
2157 msg_head = genlmsg_put(skb, 0, 0, &nbd_genl_family, 0,
2158 NBD_CMD_LINK_DEAD);
2159 if (!msg_head) {
2160 nlmsg_free(skb);
2161 return;
2162 }
2163 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2164 if (ret) {
2165 nlmsg_free(skb);
2166 return;
2167 }
2168 genlmsg_end(skb, msg_head);
2169 genlmsg_multicast(&nbd_genl_family, skb, 0, 0, GFP_KERNEL);
2170 }
2171
2172 static void nbd_dead_link_work(struct work_struct *work)
2173 {
2174 struct link_dead_args *args = container_of(work, struct link_dead_args,
2175 work);
2176 nbd_mcast_index(args->index);
2177 kfree(args);
2178 }
2179
2180 static int __init nbd_init(void)
2181 {
2182 int i;
2183
2184 BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
2185
2186 if (max_part < 0) {
2187 printk(KERN_ERR "nbd: max_part must be >= 0\n");
2188 return -EINVAL;
2189 }
2190
2191 part_shift = 0;
2192 if (max_part > 0) {
2193 part_shift = fls(max_part);
2194
2195 /*
2196 * Adjust max_part according to part_shift as it is exported
2197 * to user space so that user can know the max number of
2198 * partition kernel should be able to manage.
2199 *
2200 * Note that -1 is required because partition 0 is reserved
2201 * for the whole disk.
2202 */
2203 max_part = (1UL << part_shift) - 1;
2204 }
2205
2206 if ((1UL << part_shift) > DISK_MAX_PARTS)
2207 return -EINVAL;
2208
2209 if (nbds_max > 1UL << (MINORBITS - part_shift))
2210 return -EINVAL;
2211 recv_workqueue = alloc_workqueue("knbd-recv",
2212 WQ_MEM_RECLAIM | WQ_HIGHPRI |
2213 WQ_UNBOUND, 0);
2214 if (!recv_workqueue)
2215 return -ENOMEM;
2216
2217 if (register_blkdev(NBD_MAJOR, "nbd")) {
2218 destroy_workqueue(recv_workqueue);
2219 return -EIO;
2220 }
2221
2222 if (genl_register_family(&nbd_genl_family)) {
2223 unregister_blkdev(NBD_MAJOR, "nbd");
2224 destroy_workqueue(recv_workqueue);
2225 return -EINVAL;
2226 }
2227 nbd_dbg_init();
2228
2229 mutex_lock(&nbd_index_mutex);
2230 for (i = 0; i < nbds_max; i++)
2231 nbd_dev_add(i);
2232 mutex_unlock(&nbd_index_mutex);
2233 return 0;
2234 }
2235
2236 static int nbd_exit_cb(int id, void *ptr, void *data)
2237 {
2238 struct list_head *list = (struct list_head *)data;
2239 struct nbd_device *nbd = ptr;
2240
2241 list_add_tail(&nbd->list, list);
2242 return 0;
2243 }
2244
2245 static void __exit nbd_cleanup(void)
2246 {
2247 struct nbd_device *nbd;
2248 LIST_HEAD(del_list);
2249
2250 nbd_dbg_close();
2251
2252 mutex_lock(&nbd_index_mutex);
2253 idr_for_each(&nbd_index_idr, &nbd_exit_cb, &del_list);
2254 mutex_unlock(&nbd_index_mutex);
2255
2256 while (!list_empty(&del_list)) {
2257 nbd = list_first_entry(&del_list, struct nbd_device, list);
2258 list_del_init(&nbd->list);
2259 if (refcount_read(&nbd->refs) != 1)
2260 printk(KERN_ERR "nbd: possibly leaking a device\n");
2261 nbd_put(nbd);
2262 }
2263
2264 idr_destroy(&nbd_index_idr);
2265 genl_unregister_family(&nbd_genl_family);
2266 destroy_workqueue(recv_workqueue);
2267 unregister_blkdev(NBD_MAJOR, "nbd");
2268 }
2269
2270 module_init(nbd_init);
2271 module_exit(nbd_cleanup);
2272
2273 MODULE_DESCRIPTION("Network Block Device");
2274 MODULE_LICENSE("GPL");
2275
2276 module_param(nbds_max, int, 0444);
2277 MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
2278 module_param(max_part, int, 0444);
2279 MODULE_PARM_DESC(max_part, "number of partitions per device (default: 16)");
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