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Merge branch 'work.regset' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
[linux/fpc-iii.git] / drivers / block / nbd.c
blob3ff4054d6834d25f2b8afae4e99d5e2db2994f4e
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Network block device - make block devices work over TCP
4 *
5 * Note that you can not swap over this thing, yet. Seems to work but
6 * deadlocks sometimes - you can not swap over TCP in general.
7 *
8 * Copyright 1997-2000, 2008 Pavel Machek <pavel@ucw.cz>
9 * Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com>
10 *
11 * (part of code stolen from loop.c)
12 */
13
14 #include <linux/major.h>
15
16 #include <linux/blkdev.h>
17 #include <linux/module.h>
18 #include <linux/init.h>
19 #include <linux/sched.h>
20 #include <linux/sched/mm.h>
21 #include <linux/fs.h>
22 #include <linux/bio.h>
23 #include <linux/stat.h>
24 #include <linux/errno.h>
25 #include <linux/file.h>
26 #include <linux/ioctl.h>
27 #include <linux/mutex.h>
28 #include <linux/compiler.h>
29 #include <linux/completion.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 #define CREATE_TRACE_POINTS
48 #include <trace/events/nbd.h>
49
50 static DEFINE_IDR(nbd_index_idr);
51 static DEFINE_MUTEX(nbd_index_mutex);
52 static int nbd_total_devices = 0;
53
54 struct nbd_sock {
55 struct socket *sock;
56 struct mutex tx_lock;
57 struct request *pending;
58 int sent;
59 bool dead;
60 int fallback_index;
61 int cookie;
62 };
63
64 struct recv_thread_args {
65 struct work_struct work;
66 struct nbd_device *nbd;
67 int index;
68 };
69
70 struct link_dead_args {
71 struct work_struct work;
72 int index;
73 };
74
75 #define NBD_RT_TIMEDOUT 0
76 #define NBD_RT_DISCONNECT_REQUESTED 1
77 #define NBD_RT_DISCONNECTED 2
78 #define NBD_RT_HAS_PID_FILE 3
79 #define NBD_RT_HAS_CONFIG_REF 4
80 #define NBD_RT_BOUND 5
81 #define NBD_RT_DESTROY_ON_DISCONNECT 6
82 #define NBD_RT_DISCONNECT_ON_CLOSE 7
83
84 #define NBD_DESTROY_ON_DISCONNECT 0
85 #define NBD_DISCONNECT_REQUESTED 1
86
87 struct nbd_config {
88 u32 flags;
89 unsigned long runtime_flags;
90 u64 dead_conn_timeout;
91
92 struct nbd_sock **socks;
93 int num_connections;
94 atomic_t live_connections;
95 wait_queue_head_t conn_wait;
96
97 atomic_t recv_threads;
98 wait_queue_head_t recv_wq;
99 loff_t blksize;
100 loff_t bytesize;
101 #if IS_ENABLED(CONFIG_DEBUG_FS)
102 struct dentry *dbg_dir;
103 #endif
104 };
105
106 struct nbd_device {
107 struct blk_mq_tag_set tag_set;
108
109 int index;
110 refcount_t config_refs;
111 refcount_t refs;
112 struct nbd_config *config;
113 struct mutex config_lock;
114 struct gendisk *disk;
115 struct workqueue_struct *recv_workq;
116
117 struct list_head list;
118 struct task_struct *task_recv;
119 struct task_struct *task_setup;
120
121 struct completion *destroy_complete;
122 unsigned long flags;
123 };
124
125 #define NBD_CMD_REQUEUED 1
126
127 struct nbd_cmd {
128 struct nbd_device *nbd;
129 struct mutex lock;
130 int index;
131 int cookie;
132 int retries;
133 blk_status_t status;
134 unsigned long flags;
135 u32 cmd_cookie;
136 };
137
138 #if IS_ENABLED(CONFIG_DEBUG_FS)
139 static struct dentry *nbd_dbg_dir;
140 #endif
141
142 #define nbd_name(nbd) ((nbd)->disk->disk_name)
143
144 #define NBD_MAGIC 0x68797548
145
146 #define NBD_DEF_BLKSIZE 1024
147
148 static unsigned int nbds_max = 16;
149 static int max_part = 16;
150 static int part_shift;
151
152 static int nbd_dev_dbg_init(struct nbd_device *nbd);
153 static void nbd_dev_dbg_close(struct nbd_device *nbd);
154 static void nbd_config_put(struct nbd_device *nbd);
155 static void nbd_connect_reply(struct genl_info *info, int index);
156 static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info);
157 static void nbd_dead_link_work(struct work_struct *work);
158 static void nbd_disconnect_and_put(struct nbd_device *nbd);
159
160 static inline struct device *nbd_to_dev(struct nbd_device *nbd)
161 {
162 return disk_to_dev(nbd->disk);
163 }
164
165 static void nbd_requeue_cmd(struct nbd_cmd *cmd)
166 {
167 struct request *req = blk_mq_rq_from_pdu(cmd);
168
169 if (!test_and_set_bit(NBD_CMD_REQUEUED, &cmd->flags))
170 blk_mq_requeue_request(req, true);
171 }
172
173 #define NBD_COOKIE_BITS 32
174
175 static u64 nbd_cmd_handle(struct nbd_cmd *cmd)
176 {
177 struct request *req = blk_mq_rq_from_pdu(cmd);
178 u32 tag = blk_mq_unique_tag(req);
179 u64 cookie = cmd->cmd_cookie;
180
181 return (cookie << NBD_COOKIE_BITS) | tag;
182 }
183
184 static u32 nbd_handle_to_tag(u64 handle)
185 {
186 return (u32)handle;
187 }
188
189 static u32 nbd_handle_to_cookie(u64 handle)
190 {
191 return (u32)(handle >> NBD_COOKIE_BITS);
192 }
193
194 static const char *nbdcmd_to_ascii(int cmd)
195 {
196 switch (cmd) {
197 case NBD_CMD_READ: return "read";
198 case NBD_CMD_WRITE: return "write";
199 case NBD_CMD_DISC: return "disconnect";
200 case NBD_CMD_FLUSH: return "flush";
201 case NBD_CMD_TRIM: return "trim/discard";
202 }
203 return "invalid";
204 }
205
206 static ssize_t pid_show(struct device *dev,
207 struct device_attribute *attr, char *buf)
208 {
209 struct gendisk *disk = dev_to_disk(dev);
210 struct nbd_device *nbd = (struct nbd_device *)disk->private_data;
211
212 return sprintf(buf, "%d\n", task_pid_nr(nbd->task_recv));
213 }
214
215 static const struct device_attribute pid_attr = {
216 .attr = { .name = "pid", .mode = 0444},
217 .show = pid_show,
218 };
219
220 static void nbd_dev_remove(struct nbd_device *nbd)
221 {
222 struct gendisk *disk = nbd->disk;
223 struct request_queue *q;
224
225 if (disk) {
226 q = disk->queue;
227 del_gendisk(disk);
228 blk_cleanup_queue(q);
229 blk_mq_free_tag_set(&nbd->tag_set);
230 disk->private_data = NULL;
231 put_disk(disk);
232 }
233
234 /*
235 * Place this in the last just before the nbd is freed to
236 * make sure that the disk and the related kobject are also
237 * totally removed to avoid duplicate creation of the same
238 * one.
239 */
240 if (test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags) && nbd->destroy_complete)
241 complete(nbd->destroy_complete);
242
243 kfree(nbd);
244 }
245
246 static void nbd_put(struct nbd_device *nbd)
247 {
248 if (refcount_dec_and_mutex_lock(&nbd->refs,
249 &nbd_index_mutex)) {
250 idr_remove(&nbd_index_idr, nbd->index);
251 nbd_dev_remove(nbd);
252 mutex_unlock(&nbd_index_mutex);
253 }
254 }
255
256 static int nbd_disconnected(struct nbd_config *config)
257 {
258 return test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags) ||
259 test_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags);
260 }
261
262 static void nbd_mark_nsock_dead(struct nbd_device *nbd, struct nbd_sock *nsock,
263 int notify)
264 {
265 if (!nsock->dead && notify && !nbd_disconnected(nbd->config)) {
266 struct link_dead_args *args;
267 args = kmalloc(sizeof(struct link_dead_args), GFP_NOIO);
268 if (args) {
269 INIT_WORK(&args->work, nbd_dead_link_work);
270 args->index = nbd->index;
271 queue_work(system_wq, &args->work);
272 }
273 }
274 if (!nsock->dead) {
275 kernel_sock_shutdown(nsock->sock, SHUT_RDWR);
276 if (atomic_dec_return(&nbd->config->live_connections) == 0) {
277 if (test_and_clear_bit(NBD_RT_DISCONNECT_REQUESTED,
278 &nbd->config->runtime_flags)) {
279 set_bit(NBD_RT_DISCONNECTED,
280 &nbd->config->runtime_flags);
281 dev_info(nbd_to_dev(nbd),
282 "Disconnected due to user request.\n");
283 }
284 }
285 }
286 nsock->dead = true;
287 nsock->pending = NULL;
288 nsock->sent = 0;
289 }
290
291 static void nbd_size_clear(struct nbd_device *nbd)
292 {
293 if (nbd->config->bytesize) {
294 set_capacity(nbd->disk, 0);
295 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
296 }
297 }
298
299 static void nbd_size_update(struct nbd_device *nbd)
300 {
301 struct nbd_config *config = nbd->config;
302 struct block_device *bdev = bdget_disk(nbd->disk, 0);
303
304 if (config->flags & NBD_FLAG_SEND_TRIM) {
305 nbd->disk->queue->limits.discard_granularity = config->blksize;
306 nbd->disk->queue->limits.discard_alignment = config->blksize;
307 blk_queue_max_discard_sectors(nbd->disk->queue, UINT_MAX);
308 }
309 blk_queue_logical_block_size(nbd->disk->queue, config->blksize);
310 blk_queue_physical_block_size(nbd->disk->queue, config->blksize);
311 set_capacity(nbd->disk, config->bytesize >> 9);
312 if (bdev) {
313 if (bdev->bd_disk) {
314 bd_set_size(bdev, config->bytesize);
315 set_blocksize(bdev, config->blksize);
316 } else
317 bdev->bd_invalidated = 1;
318 bdput(bdev);
319 }
320 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
321 }
322
323 static void nbd_size_set(struct nbd_device *nbd, loff_t blocksize,
324 loff_t nr_blocks)
325 {
326 struct nbd_config *config = nbd->config;
327 config->blksize = blocksize;
328 config->bytesize = blocksize * nr_blocks;
329 if (nbd->task_recv != NULL)
330 nbd_size_update(nbd);
331 }
332
333 static void nbd_complete_rq(struct request *req)
334 {
335 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
336
337 dev_dbg(nbd_to_dev(cmd->nbd), "request %p: %s\n", req,
338 cmd->status ? "failed" : "done");
339
340 blk_mq_end_request(req, cmd->status);
341 }
342
343 /*
344 * Forcibly shutdown the socket causing all listeners to error
345 */
346 static void sock_shutdown(struct nbd_device *nbd)
347 {
348 struct nbd_config *config = nbd->config;
349 int i;
350
351 if (config->num_connections == 0)
352 return;
353 if (test_and_set_bit(NBD_RT_DISCONNECTED, &config->runtime_flags))
354 return;
355
356 for (i = 0; i < config->num_connections; i++) {
357 struct nbd_sock *nsock = config->socks[i];
358 mutex_lock(&nsock->tx_lock);
359 nbd_mark_nsock_dead(nbd, nsock, 0);
360 mutex_unlock(&nsock->tx_lock);
361 }
362 dev_warn(disk_to_dev(nbd->disk), "shutting down sockets\n");
363 }
364
365 static u32 req_to_nbd_cmd_type(struct request *req)
366 {
367 switch (req_op(req)) {
368 case REQ_OP_DISCARD:
369 return NBD_CMD_TRIM;
370 case REQ_OP_FLUSH:
371 return NBD_CMD_FLUSH;
372 case REQ_OP_WRITE:
373 return NBD_CMD_WRITE;
374 case REQ_OP_READ:
375 return NBD_CMD_READ;
376 default:
377 return U32_MAX;
378 }
379 }
380
381 static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
382 bool reserved)
383 {
384 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
385 struct nbd_device *nbd = cmd->nbd;
386 struct nbd_config *config;
387
388 if (!mutex_trylock(&cmd->lock))
389 return BLK_EH_RESET_TIMER;
390
391 if (!refcount_inc_not_zero(&nbd->config_refs)) {
392 cmd->status = BLK_STS_TIMEOUT;
393 mutex_unlock(&cmd->lock);
394 goto done;
395 }
396 config = nbd->config;
397
398 if (config->num_connections > 1 ||
399 (config->num_connections == 1 && nbd->tag_set.timeout)) {
400 dev_err_ratelimited(nbd_to_dev(nbd),
401 "Connection timed out, retrying (%d/%d alive)\n",
402 atomic_read(&config->live_connections),
403 config->num_connections);
404 /*
405 * Hooray we have more connections, requeue this IO, the submit
406 * path will put it on a real connection. Or if only one
407 * connection is configured, the submit path will wait util
408 * a new connection is reconfigured or util dead timeout.
409 */
410 if (config->socks) {
411 if (cmd->index < config->num_connections) {
412 struct nbd_sock *nsock =
413 config->socks[cmd->index];
414 mutex_lock(&nsock->tx_lock);
415 /* We can have multiple outstanding requests, so
416 * we don't want to mark the nsock dead if we've
417 * already reconnected with a new socket, so
418 * only mark it dead if its the same socket we
419 * were sent out on.
420 */
421 if (cmd->cookie == nsock->cookie)
422 nbd_mark_nsock_dead(nbd, nsock, 1);
423 mutex_unlock(&nsock->tx_lock);
424 }
425 mutex_unlock(&cmd->lock);
426 nbd_requeue_cmd(cmd);
427 nbd_config_put(nbd);
428 return BLK_EH_DONE;
429 }
430 }
431
432 if (!nbd->tag_set.timeout) {
433 /*
434 * Userspace sets timeout=0 to disable socket disconnection,
435 * so just warn and reset the timer.
436 */
437 struct nbd_sock *nsock = config->socks[cmd->index];
438 cmd->retries++;
439 dev_info(nbd_to_dev(nbd), "Possible stuck request %p: control (%s@%llu,%uB). Runtime %u seconds\n",
440 req, nbdcmd_to_ascii(req_to_nbd_cmd_type(req)),
441 (unsigned long long)blk_rq_pos(req) << 9,
442 blk_rq_bytes(req), (req->timeout / HZ) * cmd->retries);
443
444 mutex_lock(&nsock->tx_lock);
445 if (cmd->cookie != nsock->cookie) {
446 nbd_requeue_cmd(cmd);
447 mutex_unlock(&nsock->tx_lock);
448 mutex_unlock(&cmd->lock);
449 nbd_config_put(nbd);
450 return BLK_EH_DONE;
451 }
452 mutex_unlock(&nsock->tx_lock);
453 mutex_unlock(&cmd->lock);
454 nbd_config_put(nbd);
455 return BLK_EH_RESET_TIMER;
456 }
457
458 dev_err_ratelimited(nbd_to_dev(nbd), "Connection timed out\n");
459 set_bit(NBD_RT_TIMEDOUT, &config->runtime_flags);
460 cmd->status = BLK_STS_IOERR;
461 mutex_unlock(&cmd->lock);
462 sock_shutdown(nbd);
463 nbd_config_put(nbd);
464 done:
465 blk_mq_complete_request(req);
466 return BLK_EH_DONE;
467 }
468
469 /*
470 * Send or receive packet.
471 */
472 static int sock_xmit(struct nbd_device *nbd, int index, int send,
473 struct iov_iter *iter, int msg_flags, int *sent)
474 {
475 struct nbd_config *config = nbd->config;
476 struct socket *sock = config->socks[index]->sock;
477 int result;
478 struct msghdr msg;
479 unsigned int noreclaim_flag;
480
481 if (unlikely(!sock)) {
482 dev_err_ratelimited(disk_to_dev(nbd->disk),
483 "Attempted %s on closed socket in sock_xmit\n",
484 (send ? "send" : "recv"));
485 return -EINVAL;
486 }
487
488 msg.msg_iter = *iter;
489
490 noreclaim_flag = memalloc_noreclaim_save();
491 do {
492 sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC;
493 msg.msg_name = NULL;
494 msg.msg_namelen = 0;
495 msg.msg_control = NULL;
496 msg.msg_controllen = 0;
497 msg.msg_flags = msg_flags | MSG_NOSIGNAL;
498
499 if (send)
500 result = sock_sendmsg(sock, &msg);
501 else
502 result = sock_recvmsg(sock, &msg, msg.msg_flags);
503
504 if (result <= 0) {
505 if (result == 0)
506 result = -EPIPE; /* short read */
507 break;
508 }
509 if (sent)
510 *sent += result;
511 } while (msg_data_left(&msg));
512
513 memalloc_noreclaim_restore(noreclaim_flag);
514
515 return result;
516 }
517
518 /*
519 * Different settings for sk->sk_sndtimeo can result in different return values
520 * if there is a signal pending when we enter sendmsg, because reasons?
521 */
522 static inline int was_interrupted(int result)
523 {
524 return result == -ERESTARTSYS || result == -EINTR;
525 }
526
527 /* always call with the tx_lock held */
528 static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
529 {
530 struct request *req = blk_mq_rq_from_pdu(cmd);
531 struct nbd_config *config = nbd->config;
532 struct nbd_sock *nsock = config->socks[index];
533 int result;
534 struct nbd_request request = {.magic = htonl(NBD_REQUEST_MAGIC)};
535 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
536 struct iov_iter from;
537 unsigned long size = blk_rq_bytes(req);
538 struct bio *bio;
539 u64 handle;
540 u32 type;
541 u32 nbd_cmd_flags = 0;
542 int sent = nsock->sent, skip = 0;
543
544 iov_iter_kvec(&from, WRITE, &iov, 1, sizeof(request));
545
546 type = req_to_nbd_cmd_type(req);
547 if (type == U32_MAX)
548 return -EIO;
549
550 if (rq_data_dir(req) == WRITE &&
551 (config->flags & NBD_FLAG_READ_ONLY)) {
552 dev_err_ratelimited(disk_to_dev(nbd->disk),
553 "Write on read-only\n");
554 return -EIO;
555 }
556
557 if (req->cmd_flags & REQ_FUA)
558 nbd_cmd_flags |= NBD_CMD_FLAG_FUA;
559
560 /* We did a partial send previously, and we at least sent the whole
561 * request struct, so just go and send the rest of the pages in the
562 * request.
563 */
564 if (sent) {
565 if (sent >= sizeof(request)) {
566 skip = sent - sizeof(request);
567
568 /* initialize handle for tracing purposes */
569 handle = nbd_cmd_handle(cmd);
570
571 goto send_pages;
572 }
573 iov_iter_advance(&from, sent);
574 } else {
575 cmd->cmd_cookie++;
576 }
577 cmd->index = index;
578 cmd->cookie = nsock->cookie;
579 cmd->retries = 0;
580 request.type = htonl(type | nbd_cmd_flags);
581 if (type != NBD_CMD_FLUSH) {
582 request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
583 request.len = htonl(size);
584 }
585 handle = nbd_cmd_handle(cmd);
586 memcpy(request.handle, &handle, sizeof(handle));
587
588 trace_nbd_send_request(&request, nbd->index, blk_mq_rq_from_pdu(cmd));
589
590 dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n",
591 req, nbdcmd_to_ascii(type),
592 (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req));
593 result = sock_xmit(nbd, index, 1, &from,
594 (type == NBD_CMD_WRITE) ? MSG_MORE : 0, &sent);
595 trace_nbd_header_sent(req, handle);
596 if (result <= 0) {
597 if (was_interrupted(result)) {
598 /* If we havne't sent anything we can just return BUSY,
599 * however if we have sent something we need to make
600 * sure we only allow this req to be sent until we are
601 * completely done.
602 */
603 if (sent) {
604 nsock->pending = req;
605 nsock->sent = sent;
606 }
607 set_bit(NBD_CMD_REQUEUED, &cmd->flags);
608 return BLK_STS_RESOURCE;
609 }
610 dev_err_ratelimited(disk_to_dev(nbd->disk),
611 "Send control failed (result %d)\n", result);
612 return -EAGAIN;
613 }
614 send_pages:
615 if (type != NBD_CMD_WRITE)
616 goto out;
617
618 bio = req->bio;
619 while (bio) {
620 struct bio *next = bio->bi_next;
621 struct bvec_iter iter;
622 struct bio_vec bvec;
623
624 bio_for_each_segment(bvec, bio, iter) {
625 bool is_last = !next && bio_iter_last(bvec, iter);
626 int flags = is_last ? 0 : MSG_MORE;
627
628 dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n",
629 req, bvec.bv_len);
630 iov_iter_bvec(&from, WRITE, &bvec, 1, bvec.bv_len);
631 if (skip) {
632 if (skip >= iov_iter_count(&from)) {
633 skip -= iov_iter_count(&from);
634 continue;
635 }
636 iov_iter_advance(&from, skip);
637 skip = 0;
638 }
639 result = sock_xmit(nbd, index, 1, &from, flags, &sent);
640 if (result <= 0) {
641 if (was_interrupted(result)) {
642 /* We've already sent the header, we
643 * have no choice but to set pending and
644 * return BUSY.
645 */
646 nsock->pending = req;
647 nsock->sent = sent;
648 set_bit(NBD_CMD_REQUEUED, &cmd->flags);
649 return BLK_STS_RESOURCE;
650 }
651 dev_err(disk_to_dev(nbd->disk),
652 "Send data failed (result %d)\n",
653 result);
654 return -EAGAIN;
655 }
656 /*
657 * The completion might already have come in,
658 * so break for the last one instead of letting
659 * the iterator do it. This prevents use-after-free
660 * of the bio.
661 */
662 if (is_last)
663 break;
664 }
665 bio = next;
666 }
667 out:
668 trace_nbd_payload_sent(req, handle);
669 nsock->pending = NULL;
670 nsock->sent = 0;
671 return 0;
672 }
673
674 /* NULL returned = something went wrong, inform userspace */
675 static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
676 {
677 struct nbd_config *config = nbd->config;
678 int result;
679 struct nbd_reply reply;
680 struct nbd_cmd *cmd;
681 struct request *req = NULL;
682 u64 handle;
683 u16 hwq;
684 u32 tag;
685 struct kvec iov = {.iov_base = &reply, .iov_len = sizeof(reply)};
686 struct iov_iter to;
687 int ret = 0;
688
689 reply.magic = 0;
690 iov_iter_kvec(&to, READ, &iov, 1, sizeof(reply));
691 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
692 if (result <= 0) {
693 if (!nbd_disconnected(config))
694 dev_err(disk_to_dev(nbd->disk),
695 "Receive control failed (result %d)\n", result);
696 return ERR_PTR(result);
697 }
698
699 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) {
700 dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n",
701 (unsigned long)ntohl(reply.magic));
702 return ERR_PTR(-EPROTO);
703 }
704
705 memcpy(&handle, reply.handle, sizeof(handle));
706 tag = nbd_handle_to_tag(handle);
707 hwq = blk_mq_unique_tag_to_hwq(tag);
708 if (hwq < nbd->tag_set.nr_hw_queues)
709 req = blk_mq_tag_to_rq(nbd->tag_set.tags[hwq],
710 blk_mq_unique_tag_to_tag(tag));
711 if (!req || !blk_mq_request_started(req)) {
712 dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%d) %p\n",
713 tag, req);
714 return ERR_PTR(-ENOENT);
715 }
716 trace_nbd_header_received(req, handle);
717 cmd = blk_mq_rq_to_pdu(req);
718
719 mutex_lock(&cmd->lock);
720 if (cmd->cmd_cookie != nbd_handle_to_cookie(handle)) {
721 dev_err(disk_to_dev(nbd->disk), "Double reply on req %p, cmd_cookie %u, handle cookie %u\n",
722 req, cmd->cmd_cookie, nbd_handle_to_cookie(handle));
723 ret = -ENOENT;
724 goto out;
725 }
726 if (cmd->status != BLK_STS_OK) {
727 dev_err(disk_to_dev(nbd->disk), "Command already handled %p\n",
728 req);
729 ret = -ENOENT;
730 goto out;
731 }
732 if (test_bit(NBD_CMD_REQUEUED, &cmd->flags)) {
733 dev_err(disk_to_dev(nbd->disk), "Raced with timeout on req %p\n",
734 req);
735 ret = -ENOENT;
736 goto out;
737 }
738 if (ntohl(reply.error)) {
739 dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n",
740 ntohl(reply.error));
741 cmd->status = BLK_STS_IOERR;
742 goto out;
743 }
744
745 dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", req);
746 if (rq_data_dir(req) != WRITE) {
747 struct req_iterator iter;
748 struct bio_vec bvec;
749
750 rq_for_each_segment(bvec, req, iter) {
751 iov_iter_bvec(&to, READ, &bvec, 1, bvec.bv_len);
752 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
753 if (result <= 0) {
754 dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
755 result);
756 /*
757 * If we've disconnected, we need to make sure we
758 * complete this request, otherwise error out
759 * and let the timeout stuff handle resubmitting
760 * this request onto another connection.
761 */
762 if (nbd_disconnected(config)) {
763 cmd->status = BLK_STS_IOERR;
764 goto out;
765 }
766 ret = -EIO;
767 goto out;
768 }
769 dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n",
770 req, bvec.bv_len);
771 }
772 }
773 out:
774 trace_nbd_payload_received(req, handle);
775 mutex_unlock(&cmd->lock);
776 return ret ? ERR_PTR(ret) : cmd;
777 }
778
779 static void recv_work(struct work_struct *work)
780 {
781 struct recv_thread_args *args = container_of(work,
782 struct recv_thread_args,
783 work);
784 struct nbd_device *nbd = args->nbd;
785 struct nbd_config *config = nbd->config;
786 struct nbd_cmd *cmd;
787 struct request *rq;
788
789 while (1) {
790 cmd = nbd_read_stat(nbd, args->index);
791 if (IS_ERR(cmd)) {
792 struct nbd_sock *nsock = config->socks[args->index];
793
794 mutex_lock(&nsock->tx_lock);
795 nbd_mark_nsock_dead(nbd, nsock, 1);
796 mutex_unlock(&nsock->tx_lock);
797 break;
798 }
799
800 rq = blk_mq_rq_from_pdu(cmd);
801 if (likely(!blk_should_fake_timeout(rq->q)))
802 blk_mq_complete_request(rq);
803 }
804 atomic_dec(&config->recv_threads);
805 wake_up(&config->recv_wq);
806 nbd_config_put(nbd);
807 kfree(args);
808 }
809
810 static bool nbd_clear_req(struct request *req, void *data, bool reserved)
811 {
812 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
813
814 mutex_lock(&cmd->lock);
815 cmd->status = BLK_STS_IOERR;
816 mutex_unlock(&cmd->lock);
817
818 blk_mq_complete_request(req);
819 return true;
820 }
821
822 static void nbd_clear_que(struct nbd_device *nbd)
823 {
824 blk_mq_quiesce_queue(nbd->disk->queue);
825 blk_mq_tagset_busy_iter(&nbd->tag_set, nbd_clear_req, NULL);
826 blk_mq_unquiesce_queue(nbd->disk->queue);
827 dev_dbg(disk_to_dev(nbd->disk), "queue cleared\n");
828 }
829
830 static int find_fallback(struct nbd_device *nbd, int index)
831 {
832 struct nbd_config *config = nbd->config;
833 int new_index = -1;
834 struct nbd_sock *nsock = config->socks[index];
835 int fallback = nsock->fallback_index;
836
837 if (test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags))
838 return new_index;
839
840 if (config->num_connections <= 1) {
841 dev_err_ratelimited(disk_to_dev(nbd->disk),
842 "Dead connection, failed to find a fallback\n");
843 return new_index;
844 }
845
846 if (fallback >= 0 && fallback < config->num_connections &&
847 !config->socks[fallback]->dead)
848 return fallback;
849
850 if (nsock->fallback_index < 0 ||
851 nsock->fallback_index >= config->num_connections ||
852 config->socks[nsock->fallback_index]->dead) {
853 int i;
854 for (i = 0; i < config->num_connections; i++) {
855 if (i == index)
856 continue;
857 if (!config->socks[i]->dead) {
858 new_index = i;
859 break;
860 }
861 }
862 nsock->fallback_index = new_index;
863 if (new_index < 0) {
864 dev_err_ratelimited(disk_to_dev(nbd->disk),
865 "Dead connection, failed to find a fallback\n");
866 return new_index;
867 }
868 }
869 new_index = nsock->fallback_index;
870 return new_index;
871 }
872
873 static int wait_for_reconnect(struct nbd_device *nbd)
874 {
875 struct nbd_config *config = nbd->config;
876 if (!config->dead_conn_timeout)
877 return 0;
878 if (test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags))
879 return 0;
880 return wait_event_timeout(config->conn_wait,
881 atomic_read(&config->live_connections) > 0,
882 config->dead_conn_timeout) > 0;
883 }
884
885 static int nbd_handle_cmd(struct nbd_cmd *cmd, int index)
886 {
887 struct request *req = blk_mq_rq_from_pdu(cmd);
888 struct nbd_device *nbd = cmd->nbd;
889 struct nbd_config *config;
890 struct nbd_sock *nsock;
891 int ret;
892
893 if (!refcount_inc_not_zero(&nbd->config_refs)) {
894 dev_err_ratelimited(disk_to_dev(nbd->disk),
895 "Socks array is empty\n");
896 blk_mq_start_request(req);
897 return -EINVAL;
898 }
899 config = nbd->config;
900
901 if (index >= config->num_connections) {
902 dev_err_ratelimited(disk_to_dev(nbd->disk),
903 "Attempted send on invalid socket\n");
904 nbd_config_put(nbd);
905 blk_mq_start_request(req);
906 return -EINVAL;
907 }
908 cmd->status = BLK_STS_OK;
909 again:
910 nsock = config->socks[index];
911 mutex_lock(&nsock->tx_lock);
912 if (nsock->dead) {
913 int old_index = index;
914 index = find_fallback(nbd, index);
915 mutex_unlock(&nsock->tx_lock);
916 if (index < 0) {
917 if (wait_for_reconnect(nbd)) {
918 index = old_index;
919 goto again;
920 }
921 /* All the sockets should already be down at this point,
922 * we just want to make sure that DISCONNECTED is set so
923 * any requests that come in that were queue'ed waiting
924 * for the reconnect timer don't trigger the timer again
925 * and instead just error out.
926 */
927 sock_shutdown(nbd);
928 nbd_config_put(nbd);
929 blk_mq_start_request(req);
930 return -EIO;
931 }
932 goto again;
933 }
934
935 /* Handle the case that we have a pending request that was partially
936 * transmitted that _has_ to be serviced first. We need to call requeue
937 * here so that it gets put _after_ the request that is already on the
938 * dispatch list.
939 */
940 blk_mq_start_request(req);
941 if (unlikely(nsock->pending && nsock->pending != req)) {
942 nbd_requeue_cmd(cmd);
943 ret = 0;
944 goto out;
945 }
946 /*
947 * Some failures are related to the link going down, so anything that
948 * returns EAGAIN can be retried on a different socket.
949 */
950 ret = nbd_send_cmd(nbd, cmd, index);
951 if (ret == -EAGAIN) {
952 dev_err_ratelimited(disk_to_dev(nbd->disk),
953 "Request send failed, requeueing\n");
954 nbd_mark_nsock_dead(nbd, nsock, 1);
955 nbd_requeue_cmd(cmd);
956 ret = 0;
957 }
958 out:
959 mutex_unlock(&nsock->tx_lock);
960 nbd_config_put(nbd);
961 return ret;
962 }
963
964 static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
965 const struct blk_mq_queue_data *bd)
966 {
967 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
968 int ret;
969
970 /*
971 * Since we look at the bio's to send the request over the network we
972 * need to make sure the completion work doesn't mark this request done
973 * before we are done doing our send. This keeps us from dereferencing
974 * freed data if we have particularly fast completions (ie we get the
975 * completion before we exit sock_xmit on the last bvec) or in the case
976 * that the server is misbehaving (or there was an error) before we're
977 * done sending everything over the wire.
978 */
979 mutex_lock(&cmd->lock);
980 clear_bit(NBD_CMD_REQUEUED, &cmd->flags);
981
982 /* We can be called directly from the user space process, which means we
983 * could possibly have signals pending so our sendmsg will fail. In
984 * this case we need to return that we are busy, otherwise error out as
985 * appropriate.
986 */
987 ret = nbd_handle_cmd(cmd, hctx->queue_num);
988 if (ret < 0)
989 ret = BLK_STS_IOERR;
990 else if (!ret)
991 ret = BLK_STS_OK;
992 mutex_unlock(&cmd->lock);
993
994 return ret;
995 }
996
997 static struct socket *nbd_get_socket(struct nbd_device *nbd, unsigned long fd,
998 int *err)
999 {
1000 struct socket *sock;
1001
1002 *err = 0;
1003 sock = sockfd_lookup(fd, err);
1004 if (!sock)
1005 return NULL;
1006
1007 if (sock->ops->shutdown == sock_no_shutdown) {
1008 dev_err(disk_to_dev(nbd->disk), "Unsupported socket: shutdown callout must be supported.\n");
1009 *err = -EINVAL;
1010 sockfd_put(sock);
1011 return NULL;
1012 }
1013
1014 return sock;
1015 }
1016
1017 static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
1018 bool netlink)
1019 {
1020 struct nbd_config *config = nbd->config;
1021 struct socket *sock;
1022 struct nbd_sock **socks;
1023 struct nbd_sock *nsock;
1024 int err;
1025
1026 sock = nbd_get_socket(nbd, arg, &err);
1027 if (!sock)
1028 return err;
1029
1030 if (!netlink && !nbd->task_setup &&
1031 !test_bit(NBD_RT_BOUND, &config->runtime_flags))
1032 nbd->task_setup = current;
1033
1034 if (!netlink &&
1035 (nbd->task_setup != current ||
1036 test_bit(NBD_RT_BOUND, &config->runtime_flags))) {
1037 dev_err(disk_to_dev(nbd->disk),
1038 "Device being setup by another task");
1039 err = -EBUSY;
1040 goto put_socket;
1041 }
1042
1043 nsock = kzalloc(sizeof(*nsock), GFP_KERNEL);
1044 if (!nsock) {
1045 err = -ENOMEM;
1046 goto put_socket;
1047 }
1048
1049 socks = krealloc(config->socks, (config->num_connections + 1) *
1050 sizeof(struct nbd_sock *), GFP_KERNEL);
1051 if (!socks) {
1052 kfree(nsock);
1053 err = -ENOMEM;
1054 goto put_socket;
1055 }
1056
1057 config->socks = socks;
1058
1059 nsock->fallback_index = -1;
1060 nsock->dead = false;
1061 mutex_init(&nsock->tx_lock);
1062 nsock->sock = sock;
1063 nsock->pending = NULL;
1064 nsock->sent = 0;
1065 nsock->cookie = 0;
1066 socks[config->num_connections++] = nsock;
1067 atomic_inc(&config->live_connections);
1068
1069 return 0;
1070
1071 put_socket:
1072 sockfd_put(sock);
1073 return err;
1074 }
1075
1076 static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg)
1077 {
1078 struct nbd_config *config = nbd->config;
1079 struct socket *sock, *old;
1080 struct recv_thread_args *args;
1081 int i;
1082 int err;
1083
1084 sock = nbd_get_socket(nbd, arg, &err);
1085 if (!sock)
1086 return err;
1087
1088 args = kzalloc(sizeof(*args), GFP_KERNEL);
1089 if (!args) {
1090 sockfd_put(sock);
1091 return -ENOMEM;
1092 }
1093
1094 for (i = 0; i < config->num_connections; i++) {
1095 struct nbd_sock *nsock = config->socks[i];
1096
1097 if (!nsock->dead)
1098 continue;
1099
1100 mutex_lock(&nsock->tx_lock);
1101 if (!nsock->dead) {
1102 mutex_unlock(&nsock->tx_lock);
1103 continue;
1104 }
1105 sk_set_memalloc(sock->sk);
1106 if (nbd->tag_set.timeout)
1107 sock->sk->sk_sndtimeo = nbd->tag_set.timeout;
1108 atomic_inc(&config->recv_threads);
1109 refcount_inc(&nbd->config_refs);
1110 old = nsock->sock;
1111 nsock->fallback_index = -1;
1112 nsock->sock = sock;
1113 nsock->dead = false;
1114 INIT_WORK(&args->work, recv_work);
1115 args->index = i;
1116 args->nbd = nbd;
1117 nsock->cookie++;
1118 mutex_unlock(&nsock->tx_lock);
1119 sockfd_put(old);
1120
1121 clear_bit(NBD_RT_DISCONNECTED, &config->runtime_flags);
1122
1123 /* We take the tx_mutex in an error path in the recv_work, so we
1124 * need to queue_work outside of the tx_mutex.
1125 */
1126 queue_work(nbd->recv_workq, &args->work);
1127
1128 atomic_inc(&config->live_connections);
1129 wake_up(&config->conn_wait);
1130 return 0;
1131 }
1132 sockfd_put(sock);
1133 kfree(args);
1134 return -ENOSPC;
1135 }
1136
1137 static void nbd_bdev_reset(struct block_device *bdev)
1138 {
1139 if (bdev->bd_openers > 1)
1140 return;
1141 bd_set_size(bdev, 0);
1142 }
1143
1144 static void nbd_parse_flags(struct nbd_device *nbd)
1145 {
1146 struct nbd_config *config = nbd->config;
1147 if (config->flags & NBD_FLAG_READ_ONLY)
1148 set_disk_ro(nbd->disk, true);
1149 else
1150 set_disk_ro(nbd->disk, false);
1151 if (config->flags & NBD_FLAG_SEND_TRIM)
1152 blk_queue_flag_set(QUEUE_FLAG_DISCARD, nbd->disk->queue);
1153 if (config->flags & NBD_FLAG_SEND_FLUSH) {
1154 if (config->flags & NBD_FLAG_SEND_FUA)
1155 blk_queue_write_cache(nbd->disk->queue, true, true);
1156 else
1157 blk_queue_write_cache(nbd->disk->queue, true, false);
1158 }
1159 else
1160 blk_queue_write_cache(nbd->disk->queue, false, false);
1161 }
1162
1163 static void send_disconnects(struct nbd_device *nbd)
1164 {
1165 struct nbd_config *config = nbd->config;
1166 struct nbd_request request = {
1167 .magic = htonl(NBD_REQUEST_MAGIC),
1168 .type = htonl(NBD_CMD_DISC),
1169 };
1170 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
1171 struct iov_iter from;
1172 int i, ret;
1173
1174 for (i = 0; i < config->num_connections; i++) {
1175 struct nbd_sock *nsock = config->socks[i];
1176
1177 iov_iter_kvec(&from, WRITE, &iov, 1, sizeof(request));
1178 mutex_lock(&nsock->tx_lock);
1179 ret = sock_xmit(nbd, i, 1, &from, 0, NULL);
1180 if (ret <= 0)
1181 dev_err(disk_to_dev(nbd->disk),
1182 "Send disconnect failed %d\n", ret);
1183 mutex_unlock(&nsock->tx_lock);
1184 }
1185 }
1186
1187 static int nbd_disconnect(struct nbd_device *nbd)
1188 {
1189 struct nbd_config *config = nbd->config;
1190
1191 dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
1192 set_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags);
1193 set_bit(NBD_DISCONNECT_REQUESTED, &nbd->flags);
1194 send_disconnects(nbd);
1195 return 0;
1196 }
1197
1198 static void nbd_clear_sock(struct nbd_device *nbd)
1199 {
1200 sock_shutdown(nbd);
1201 nbd_clear_que(nbd);
1202 nbd->task_setup = NULL;
1203 }
1204
1205 static void nbd_config_put(struct nbd_device *nbd)
1206 {
1207 if (refcount_dec_and_mutex_lock(&nbd->config_refs,
1208 &nbd->config_lock)) {
1209 struct nbd_config *config = nbd->config;
1210 nbd_dev_dbg_close(nbd);
1211 nbd_size_clear(nbd);
1212 if (test_and_clear_bit(NBD_RT_HAS_PID_FILE,
1213 &config->runtime_flags))
1214 device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
1215 nbd->task_recv = NULL;
1216 nbd_clear_sock(nbd);
1217 if (config->num_connections) {
1218 int i;
1219 for (i = 0; i < config->num_connections; i++) {
1220 sockfd_put(config->socks[i]->sock);
1221 kfree(config->socks[i]);
1222 }
1223 kfree(config->socks);
1224 }
1225 kfree(nbd->config);
1226 nbd->config = NULL;
1227
1228 if (nbd->recv_workq)
1229 destroy_workqueue(nbd->recv_workq);
1230 nbd->recv_workq = NULL;
1231
1232 nbd->tag_set.timeout = 0;
1233 nbd->disk->queue->limits.discard_granularity = 0;
1234 nbd->disk->queue->limits.discard_alignment = 0;
1235 blk_queue_max_discard_sectors(nbd->disk->queue, UINT_MAX);
1236 blk_queue_flag_clear(QUEUE_FLAG_DISCARD, nbd->disk->queue);
1237
1238 mutex_unlock(&nbd->config_lock);
1239 nbd_put(nbd);
1240 module_put(THIS_MODULE);
1241 }
1242 }
1243
1244 static int nbd_start_device(struct nbd_device *nbd)
1245 {
1246 struct nbd_config *config = nbd->config;
1247 int num_connections = config->num_connections;
1248 int error = 0, i;
1249
1250 if (nbd->task_recv)
1251 return -EBUSY;
1252 if (!config->socks)
1253 return -EINVAL;
1254 if (num_connections > 1 &&
1255 !(config->flags & NBD_FLAG_CAN_MULTI_CONN)) {
1256 dev_err(disk_to_dev(nbd->disk), "server does not support multiple connections per device.\n");
1257 return -EINVAL;
1258 }
1259
1260 nbd->recv_workq = alloc_workqueue("knbd%d-recv",
1261 WQ_MEM_RECLAIM | WQ_HIGHPRI |
1262 WQ_UNBOUND, 0, nbd->index);
1263 if (!nbd->recv_workq) {
1264 dev_err(disk_to_dev(nbd->disk), "Could not allocate knbd recv work queue.\n");
1265 return -ENOMEM;
1266 }
1267
1268 blk_mq_update_nr_hw_queues(&nbd->tag_set, config->num_connections);
1269 nbd->task_recv = current;
1270
1271 nbd_parse_flags(nbd);
1272
1273 error = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
1274 if (error) {
1275 dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n");
1276 return error;
1277 }
1278 set_bit(NBD_RT_HAS_PID_FILE, &config->runtime_flags);
1279
1280 nbd_dev_dbg_init(nbd);
1281 for (i = 0; i < num_connections; i++) {
1282 struct recv_thread_args *args;
1283
1284 args = kzalloc(sizeof(*args), GFP_KERNEL);
1285 if (!args) {
1286 sock_shutdown(nbd);
1287 /*
1288 * If num_connections is m (2 < m),
1289 * and NO.1 ~ NO.n(1 < n < m) kzallocs are successful.
1290 * But NO.(n + 1) failed. We still have n recv threads.
1291 * So, add flush_workqueue here to prevent recv threads
1292 * dropping the last config_refs and trying to destroy
1293 * the workqueue from inside the workqueue.
1294 */
1295 if (i)
1296 flush_workqueue(nbd->recv_workq);
1297 return -ENOMEM;
1298 }
1299 sk_set_memalloc(config->socks[i]->sock->sk);
1300 if (nbd->tag_set.timeout)
1301 config->socks[i]->sock->sk->sk_sndtimeo =
1302 nbd->tag_set.timeout;
1303 atomic_inc(&config->recv_threads);
1304 refcount_inc(&nbd->config_refs);
1305 INIT_WORK(&args->work, recv_work);
1306 args->nbd = nbd;
1307 args->index = i;
1308 queue_work(nbd->recv_workq, &args->work);
1309 }
1310 nbd_size_update(nbd);
1311 return error;
1312 }
1313
1314 static int nbd_start_device_ioctl(struct nbd_device *nbd, struct block_device *bdev)
1315 {
1316 struct nbd_config *config = nbd->config;
1317 int ret;
1318
1319 ret = nbd_start_device(nbd);
1320 if (ret)
1321 return ret;
1322
1323 if (max_part)
1324 bdev->bd_invalidated = 1;
1325 mutex_unlock(&nbd->config_lock);
1326 ret = wait_event_interruptible(config->recv_wq,
1327 atomic_read(&config->recv_threads) == 0);
1328 if (ret)
1329 sock_shutdown(nbd);
1330 flush_workqueue(nbd->recv_workq);
1331
1332 mutex_lock(&nbd->config_lock);
1333 nbd_bdev_reset(bdev);
1334 /* user requested, ignore socket errors */
1335 if (test_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags))
1336 ret = 0;
1337 if (test_bit(NBD_RT_TIMEDOUT, &config->runtime_flags))
1338 ret = -ETIMEDOUT;
1339 return ret;
1340 }
1341
1342 static void nbd_clear_sock_ioctl(struct nbd_device *nbd,
1343 struct block_device *bdev)
1344 {
1345 sock_shutdown(nbd);
1346 __invalidate_device(bdev, true);
1347 nbd_bdev_reset(bdev);
1348 if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF,
1349 &nbd->config->runtime_flags))
1350 nbd_config_put(nbd);
1351 }
1352
1353 static bool nbd_is_valid_blksize(unsigned long blksize)
1354 {
1355 if (!blksize || !is_power_of_2(blksize) || blksize < 512 ||
1356 blksize > PAGE_SIZE)
1357 return false;
1358 return true;
1359 }
1360
1361 static void nbd_set_cmd_timeout(struct nbd_device *nbd, u64 timeout)
1362 {
1363 nbd->tag_set.timeout = timeout * HZ;
1364 if (timeout)
1365 blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ);
1366 }
1367
1368 /* Must be called with config_lock held */
1369 static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
1370 unsigned int cmd, unsigned long arg)
1371 {
1372 struct nbd_config *config = nbd->config;
1373
1374 switch (cmd) {
1375 case NBD_DISCONNECT:
1376 return nbd_disconnect(nbd);
1377 case NBD_CLEAR_SOCK:
1378 nbd_clear_sock_ioctl(nbd, bdev);
1379 return 0;
1380 case NBD_SET_SOCK:
1381 return nbd_add_socket(nbd, arg, false);
1382 case NBD_SET_BLKSIZE:
1383 if (!arg)
1384 arg = NBD_DEF_BLKSIZE;
1385 if (!nbd_is_valid_blksize(arg))
1386 return -EINVAL;
1387 nbd_size_set(nbd, arg,
1388 div_s64(config->bytesize, arg));
1389 return 0;
1390 case NBD_SET_SIZE:
1391 nbd_size_set(nbd, config->blksize,
1392 div_s64(arg, config->blksize));
1393 return 0;
1394 case NBD_SET_SIZE_BLOCKS:
1395 nbd_size_set(nbd, config->blksize, arg);
1396 return 0;
1397 case NBD_SET_TIMEOUT:
1398 nbd_set_cmd_timeout(nbd, arg);
1399 return 0;
1400
1401 case NBD_SET_FLAGS:
1402 config->flags = arg;
1403 return 0;
1404 case NBD_DO_IT:
1405 return nbd_start_device_ioctl(nbd, bdev);
1406 case NBD_CLEAR_QUE:
1407 /*
1408 * This is for compatibility only. The queue is always cleared
1409 * by NBD_DO_IT or NBD_CLEAR_SOCK.
1410 */
1411 return 0;
1412 case NBD_PRINT_DEBUG:
1413 /*
1414 * For compatibility only, we no longer keep a list of
1415 * outstanding requests.
1416 */
1417 return 0;
1418 }
1419 return -ENOTTY;
1420 }
1421
1422 static int nbd_ioctl(struct block_device *bdev, fmode_t mode,
1423 unsigned int cmd, unsigned long arg)
1424 {
1425 struct nbd_device *nbd = bdev->bd_disk->private_data;
1426 struct nbd_config *config = nbd->config;
1427 int error = -EINVAL;
1428
1429 if (!capable(CAP_SYS_ADMIN))
1430 return -EPERM;
1431
1432 /* The block layer will pass back some non-nbd ioctls in case we have
1433 * special handling for them, but we don't so just return an error.
1434 */
1435 if (_IOC_TYPE(cmd) != 0xab)
1436 return -EINVAL;
1437
1438 mutex_lock(&nbd->config_lock);
1439
1440 /* Don't allow ioctl operations on a nbd device that was created with
1441 * netlink, unless it's DISCONNECT or CLEAR_SOCK, which are fine.
1442 */
1443 if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) ||
1444 (cmd == NBD_DISCONNECT || cmd == NBD_CLEAR_SOCK))
1445 error = __nbd_ioctl(bdev, nbd, cmd, arg);
1446 else
1447 dev_err(nbd_to_dev(nbd), "Cannot use ioctl interface on a netlink controlled device.\n");
1448 mutex_unlock(&nbd->config_lock);
1449 return error;
1450 }
1451
1452 static struct nbd_config *nbd_alloc_config(void)
1453 {
1454 struct nbd_config *config;
1455
1456 config = kzalloc(sizeof(struct nbd_config), GFP_NOFS);
1457 if (!config)
1458 return NULL;
1459 atomic_set(&config->recv_threads, 0);
1460 init_waitqueue_head(&config->recv_wq);
1461 init_waitqueue_head(&config->conn_wait);
1462 config->blksize = NBD_DEF_BLKSIZE;
1463 atomic_set(&config->live_connections, 0);
1464 try_module_get(THIS_MODULE);
1465 return config;
1466 }
1467
1468 static int nbd_open(struct block_device *bdev, fmode_t mode)
1469 {
1470 struct nbd_device *nbd;
1471 int ret = 0;
1472
1473 mutex_lock(&nbd_index_mutex);
1474 nbd = bdev->bd_disk->private_data;
1475 if (!nbd) {
1476 ret = -ENXIO;
1477 goto out;
1478 }
1479 if (!refcount_inc_not_zero(&nbd->refs)) {
1480 ret = -ENXIO;
1481 goto out;
1482 }
1483 if (!refcount_inc_not_zero(&nbd->config_refs)) {
1484 struct nbd_config *config;
1485
1486 mutex_lock(&nbd->config_lock);
1487 if (refcount_inc_not_zero(&nbd->config_refs)) {
1488 mutex_unlock(&nbd->config_lock);
1489 goto out;
1490 }
1491 config = nbd->config = nbd_alloc_config();
1492 if (!config) {
1493 ret = -ENOMEM;
1494 mutex_unlock(&nbd->config_lock);
1495 goto out;
1496 }
1497 refcount_set(&nbd->config_refs, 1);
1498 refcount_inc(&nbd->refs);
1499 mutex_unlock(&nbd->config_lock);
1500 bdev->bd_invalidated = 1;
1501 } else if (nbd_disconnected(nbd->config)) {
1502 bdev->bd_invalidated = 1;
1503 }
1504 out:
1505 mutex_unlock(&nbd_index_mutex);
1506 return ret;
1507 }
1508
1509 static void nbd_release(struct gendisk *disk, fmode_t mode)
1510 {
1511 struct nbd_device *nbd = disk->private_data;
1512 struct block_device *bdev = bdget_disk(disk, 0);
1513
1514 if (test_bit(NBD_RT_DISCONNECT_ON_CLOSE, &nbd->config->runtime_flags) &&
1515 bdev->bd_openers == 0)
1516 nbd_disconnect_and_put(nbd);
1517
1518 nbd_config_put(nbd);
1519 nbd_put(nbd);
1520 }
1521
1522 static const struct block_device_operations nbd_fops =
1523 {
1524 .owner = THIS_MODULE,
1525 .open = nbd_open,
1526 .release = nbd_release,
1527 .ioctl = nbd_ioctl,
1528 .compat_ioctl = nbd_ioctl,
1529 };
1530
1531 #if IS_ENABLED(CONFIG_DEBUG_FS)
1532
1533 static int nbd_dbg_tasks_show(struct seq_file *s, void *unused)
1534 {
1535 struct nbd_device *nbd = s->private;
1536
1537 if (nbd->task_recv)
1538 seq_printf(s, "recv: %d\n", task_pid_nr(nbd->task_recv));
1539
1540 return 0;
1541 }
1542
1543 static int nbd_dbg_tasks_open(struct inode *inode, struct file *file)
1544 {
1545 return single_open(file, nbd_dbg_tasks_show, inode->i_private);
1546 }
1547
1548 static const struct file_operations nbd_dbg_tasks_ops = {
1549 .open = nbd_dbg_tasks_open,
1550 .read = seq_read,
1551 .llseek = seq_lseek,
1552 .release = single_release,
1553 };
1554
1555 static int nbd_dbg_flags_show(struct seq_file *s, void *unused)
1556 {
1557 struct nbd_device *nbd = s->private;
1558 u32 flags = nbd->config->flags;
1559
1560 seq_printf(s, "Hex: 0x%08x\n\n", flags);
1561
1562 seq_puts(s, "Known flags:\n");
1563
1564 if (flags & NBD_FLAG_HAS_FLAGS)
1565 seq_puts(s, "NBD_FLAG_HAS_FLAGS\n");
1566 if (flags & NBD_FLAG_READ_ONLY)
1567 seq_puts(s, "NBD_FLAG_READ_ONLY\n");
1568 if (flags & NBD_FLAG_SEND_FLUSH)
1569 seq_puts(s, "NBD_FLAG_SEND_FLUSH\n");
1570 if (flags & NBD_FLAG_SEND_FUA)
1571 seq_puts(s, "NBD_FLAG_SEND_FUA\n");
1572 if (flags & NBD_FLAG_SEND_TRIM)
1573 seq_puts(s, "NBD_FLAG_SEND_TRIM\n");
1574
1575 return 0;
1576 }
1577
1578 static int nbd_dbg_flags_open(struct inode *inode, struct file *file)
1579 {
1580 return single_open(file, nbd_dbg_flags_show, inode->i_private);
1581 }
1582
1583 static const struct file_operations nbd_dbg_flags_ops = {
1584 .open = nbd_dbg_flags_open,
1585 .read = seq_read,
1586 .llseek = seq_lseek,
1587 .release = single_release,
1588 };
1589
1590 static int nbd_dev_dbg_init(struct nbd_device *nbd)
1591 {
1592 struct dentry *dir;
1593 struct nbd_config *config = nbd->config;
1594
1595 if (!nbd_dbg_dir)
1596 return -EIO;
1597
1598 dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir);
1599 if (!dir) {
1600 dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s'\n",
1601 nbd_name(nbd));
1602 return -EIO;
1603 }
1604 config->dbg_dir = dir;
1605
1606 debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_ops);
1607 debugfs_create_u64("size_bytes", 0444, dir, &config->bytesize);
1608 debugfs_create_u32("timeout", 0444, dir, &nbd->tag_set.timeout);
1609 debugfs_create_u64("blocksize", 0444, dir, &config->blksize);
1610 debugfs_create_file("flags", 0444, dir, nbd, &nbd_dbg_flags_ops);
1611
1612 return 0;
1613 }
1614
1615 static void nbd_dev_dbg_close(struct nbd_device *nbd)
1616 {
1617 debugfs_remove_recursive(nbd->config->dbg_dir);
1618 }
1619
1620 static int nbd_dbg_init(void)
1621 {
1622 struct dentry *dbg_dir;
1623
1624 dbg_dir = debugfs_create_dir("nbd", NULL);
1625 if (!dbg_dir)
1626 return -EIO;
1627
1628 nbd_dbg_dir = dbg_dir;
1629
1630 return 0;
1631 }
1632
1633 static void nbd_dbg_close(void)
1634 {
1635 debugfs_remove_recursive(nbd_dbg_dir);
1636 }
1637
1638 #else /* IS_ENABLED(CONFIG_DEBUG_FS) */
1639
1640 static int nbd_dev_dbg_init(struct nbd_device *nbd)
1641 {
1642 return 0;
1643 }
1644
1645 static void nbd_dev_dbg_close(struct nbd_device *nbd)
1646 {
1647 }
1648
1649 static int nbd_dbg_init(void)
1650 {
1651 return 0;
1652 }
1653
1654 static void nbd_dbg_close(void)
1655 {
1656 }
1657
1658 #endif
1659
1660 static int nbd_init_request(struct blk_mq_tag_set *set, struct request *rq,
1661 unsigned int hctx_idx, unsigned int numa_node)
1662 {
1663 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq);
1664 cmd->nbd = set->driver_data;
1665 cmd->flags = 0;
1666 mutex_init(&cmd->lock);
1667 return 0;
1668 }
1669
1670 static const struct blk_mq_ops nbd_mq_ops = {
1671 .queue_rq = nbd_queue_rq,
1672 .complete = nbd_complete_rq,
1673 .init_request = nbd_init_request,
1674 .timeout = nbd_xmit_timeout,
1675 };
1676
1677 static int nbd_dev_add(int index)
1678 {
1679 struct nbd_device *nbd;
1680 struct gendisk *disk;
1681 struct request_queue *q;
1682 int err = -ENOMEM;
1683
1684 nbd = kzalloc(sizeof(struct nbd_device), GFP_KERNEL);
1685 if (!nbd)
1686 goto out;
1687
1688 disk = alloc_disk(1 << part_shift);
1689 if (!disk)
1690 goto out_free_nbd;
1691
1692 if (index >= 0) {
1693 err = idr_alloc(&nbd_index_idr, nbd, index, index + 1,
1694 GFP_KERNEL);
1695 if (err == -ENOSPC)
1696 err = -EEXIST;
1697 } else {
1698 err = idr_alloc(&nbd_index_idr, nbd, 0, 0, GFP_KERNEL);
1699 if (err >= 0)
1700 index = err;
1701 }
1702 if (err < 0)
1703 goto out_free_disk;
1704
1705 nbd->index = index;
1706 nbd->disk = disk;
1707 nbd->tag_set.ops = &nbd_mq_ops;
1708 nbd->tag_set.nr_hw_queues = 1;
1709 nbd->tag_set.queue_depth = 128;
1710 nbd->tag_set.numa_node = NUMA_NO_NODE;
1711 nbd->tag_set.cmd_size = sizeof(struct nbd_cmd);
1712 nbd->tag_set.flags = BLK_MQ_F_SHOULD_MERGE |
1713 BLK_MQ_F_BLOCKING;
1714 nbd->tag_set.driver_data = nbd;
1715 nbd->destroy_complete = NULL;
1716
1717 err = blk_mq_alloc_tag_set(&nbd->tag_set);
1718 if (err)
1719 goto out_free_idr;
1720
1721 q = blk_mq_init_queue(&nbd->tag_set);
1722 if (IS_ERR(q)) {
1723 err = PTR_ERR(q);
1724 goto out_free_tags;
1725 }
1726 disk->queue = q;
1727
1728 /*
1729 * Tell the block layer that we are not a rotational device
1730 */
1731 blk_queue_flag_set(QUEUE_FLAG_NONROT, disk->queue);
1732 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, disk->queue);
1733 disk->queue->limits.discard_granularity = 0;
1734 disk->queue->limits.discard_alignment = 0;
1735 blk_queue_max_discard_sectors(disk->queue, 0);
1736 blk_queue_max_segment_size(disk->queue, UINT_MAX);
1737 blk_queue_max_segments(disk->queue, USHRT_MAX);
1738 blk_queue_max_hw_sectors(disk->queue, 65536);
1739 disk->queue->limits.max_sectors = 256;
1740
1741 mutex_init(&nbd->config_lock);
1742 refcount_set(&nbd->config_refs, 0);
1743 refcount_set(&nbd->refs, 1);
1744 INIT_LIST_HEAD(&nbd->list);
1745 disk->major = NBD_MAJOR;
1746 disk->first_minor = index << part_shift;
1747 disk->fops = &nbd_fops;
1748 disk->private_data = nbd;
1749 sprintf(disk->disk_name, "nbd%d", index);
1750 add_disk(disk);
1751 nbd_total_devices++;
1752 return index;
1753
1754 out_free_tags:
1755 blk_mq_free_tag_set(&nbd->tag_set);
1756 out_free_idr:
1757 idr_remove(&nbd_index_idr, index);
1758 out_free_disk:
1759 put_disk(disk);
1760 out_free_nbd:
1761 kfree(nbd);
1762 out:
1763 return err;
1764 }
1765
1766 static int find_free_cb(int id, void *ptr, void *data)
1767 {
1768 struct nbd_device *nbd = ptr;
1769 struct nbd_device **found = data;
1770
1771 if (!refcount_read(&nbd->config_refs)) {
1772 *found = nbd;
1773 return 1;
1774 }
1775 return 0;
1776 }
1777
1778 /* Netlink interface. */
1779 static const struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = {
1780 [NBD_ATTR_INDEX] = { .type = NLA_U32 },
1781 [NBD_ATTR_SIZE_BYTES] = { .type = NLA_U64 },
1782 [NBD_ATTR_BLOCK_SIZE_BYTES] = { .type = NLA_U64 },
1783 [NBD_ATTR_TIMEOUT] = { .type = NLA_U64 },
1784 [NBD_ATTR_SERVER_FLAGS] = { .type = NLA_U64 },
1785 [NBD_ATTR_CLIENT_FLAGS] = { .type = NLA_U64 },
1786 [NBD_ATTR_SOCKETS] = { .type = NLA_NESTED},
1787 [NBD_ATTR_DEAD_CONN_TIMEOUT] = { .type = NLA_U64 },
1788 [NBD_ATTR_DEVICE_LIST] = { .type = NLA_NESTED},
1789 };
1790
1791 static const struct nla_policy nbd_sock_policy[NBD_SOCK_MAX + 1] = {
1792 [NBD_SOCK_FD] = { .type = NLA_U32 },
1793 };
1794
1795 /* We don't use this right now since we don't parse the incoming list, but we
1796 * still want it here so userspace knows what to expect.
1797 */
1798 static const struct nla_policy __attribute__((unused))
1799 nbd_device_policy[NBD_DEVICE_ATTR_MAX + 1] = {
1800 [NBD_DEVICE_INDEX] = { .type = NLA_U32 },
1801 [NBD_DEVICE_CONNECTED] = { .type = NLA_U8 },
1802 };
1803
1804 static int nbd_genl_size_set(struct genl_info *info, struct nbd_device *nbd)
1805 {
1806 struct nbd_config *config = nbd->config;
1807 u64 bsize = config->blksize;
1808 u64 bytes = config->bytesize;
1809
1810 if (info->attrs[NBD_ATTR_SIZE_BYTES])
1811 bytes = nla_get_u64(info->attrs[NBD_ATTR_SIZE_BYTES]);
1812
1813 if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]) {
1814 bsize = nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]);
1815 if (!bsize)
1816 bsize = NBD_DEF_BLKSIZE;
1817 if (!nbd_is_valid_blksize(bsize)) {
1818 printk(KERN_ERR "Invalid block size %llu\n", bsize);
1819 return -EINVAL;
1820 }
1821 }
1822
1823 if (bytes != config->bytesize || bsize != config->blksize)
1824 nbd_size_set(nbd, bsize, div64_u64(bytes, bsize));
1825 return 0;
1826 }
1827
1828 static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
1829 {
1830 DECLARE_COMPLETION_ONSTACK(destroy_complete);
1831 struct nbd_device *nbd = NULL;
1832 struct nbd_config *config;
1833 int index = -1;
1834 int ret;
1835 bool put_dev = false;
1836
1837 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1838 return -EPERM;
1839
1840 if (info->attrs[NBD_ATTR_INDEX])
1841 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1842 if (!info->attrs[NBD_ATTR_SOCKETS]) {
1843 printk(KERN_ERR "nbd: must specify at least one socket\n");
1844 return -EINVAL;
1845 }
1846 if (!info->attrs[NBD_ATTR_SIZE_BYTES]) {
1847 printk(KERN_ERR "nbd: must specify a size in bytes for the device\n");
1848 return -EINVAL;
1849 }
1850 again:
1851 mutex_lock(&nbd_index_mutex);
1852 if (index == -1) {
1853 ret = idr_for_each(&nbd_index_idr, &find_free_cb, &nbd);
1854 if (ret == 0) {
1855 int new_index;
1856 new_index = nbd_dev_add(-1);
1857 if (new_index < 0) {
1858 mutex_unlock(&nbd_index_mutex);
1859 printk(KERN_ERR "nbd: failed to add new device\n");
1860 return new_index;
1861 }
1862 nbd = idr_find(&nbd_index_idr, new_index);
1863 }
1864 } else {
1865 nbd = idr_find(&nbd_index_idr, index);
1866 if (!nbd) {
1867 ret = nbd_dev_add(index);
1868 if (ret < 0) {
1869 mutex_unlock(&nbd_index_mutex);
1870 printk(KERN_ERR "nbd: failed to add new device\n");
1871 return ret;
1872 }
1873 nbd = idr_find(&nbd_index_idr, index);
1874 }
1875 }
1876 if (!nbd) {
1877 printk(KERN_ERR "nbd: couldn't find device at index %d\n",
1878 index);
1879 mutex_unlock(&nbd_index_mutex);
1880 return -EINVAL;
1881 }
1882
1883 if (test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags) &&
1884 test_bit(NBD_DISCONNECT_REQUESTED, &nbd->flags)) {
1885 nbd->destroy_complete = &destroy_complete;
1886 mutex_unlock(&nbd_index_mutex);
1887
1888 /* Wait untill the the nbd stuff is totally destroyed */
1889 wait_for_completion(&destroy_complete);
1890 goto again;
1891 }
1892
1893 if (!refcount_inc_not_zero(&nbd->refs)) {
1894 mutex_unlock(&nbd_index_mutex);
1895 if (index == -1)
1896 goto again;
1897 printk(KERN_ERR "nbd: device at index %d is going down\n",
1898 index);
1899 return -EINVAL;
1900 }
1901 mutex_unlock(&nbd_index_mutex);
1902
1903 mutex_lock(&nbd->config_lock);
1904 if (refcount_read(&nbd->config_refs)) {
1905 mutex_unlock(&nbd->config_lock);
1906 nbd_put(nbd);
1907 if (index == -1)
1908 goto again;
1909 printk(KERN_ERR "nbd: nbd%d already in use\n", index);
1910 return -EBUSY;
1911 }
1912 if (WARN_ON(nbd->config)) {
1913 mutex_unlock(&nbd->config_lock);
1914 nbd_put(nbd);
1915 return -EINVAL;
1916 }
1917 config = nbd->config = nbd_alloc_config();
1918 if (!nbd->config) {
1919 mutex_unlock(&nbd->config_lock);
1920 nbd_put(nbd);
1921 printk(KERN_ERR "nbd: couldn't allocate config\n");
1922 return -ENOMEM;
1923 }
1924 refcount_set(&nbd->config_refs, 1);
1925 set_bit(NBD_RT_BOUND, &config->runtime_flags);
1926
1927 ret = nbd_genl_size_set(info, nbd);
1928 if (ret)
1929 goto out;
1930
1931 if (info->attrs[NBD_ATTR_TIMEOUT])
1932 nbd_set_cmd_timeout(nbd,
1933 nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]));
1934 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
1935 config->dead_conn_timeout =
1936 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
1937 config->dead_conn_timeout *= HZ;
1938 }
1939 if (info->attrs[NBD_ATTR_SERVER_FLAGS])
1940 config->flags =
1941 nla_get_u64(info->attrs[NBD_ATTR_SERVER_FLAGS]);
1942 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
1943 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
1944 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
1945 set_bit(NBD_RT_DESTROY_ON_DISCONNECT,
1946 &config->runtime_flags);
1947 set_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags);
1948 put_dev = true;
1949 } else {
1950 clear_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags);
1951 }
1952 if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {
1953 set_bit(NBD_RT_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_deprecated(socks, NBD_SOCK_MAX,
1972 attr,
1973 nbd_sock_policy,
1974 info->extack);
1975 if (ret != 0) {
1976 printk(KERN_ERR "nbd: error processing sock list\n");
1977 ret = -EINVAL;
1978 goto out;
1979 }
1980 if (!socks[NBD_SOCK_FD])
1981 continue;
1982 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
1983 ret = nbd_add_socket(nbd, fd, true);
1984 if (ret)
1985 goto out;
1986 }
1987 }
1988 ret = nbd_start_device(nbd);
1989 out:
1990 mutex_unlock(&nbd->config_lock);
1991 if (!ret) {
1992 set_bit(NBD_RT_HAS_CONFIG_REF, &config->runtime_flags);
1993 refcount_inc(&nbd->config_refs);
1994 nbd_connect_reply(info, nbd->index);
1995 }
1996 nbd_config_put(nbd);
1997 if (put_dev)
1998 nbd_put(nbd);
1999 return ret;
2000 }
2001
2002 static void nbd_disconnect_and_put(struct nbd_device *nbd)
2003 {
2004 mutex_lock(&nbd->config_lock);
2005 nbd_disconnect(nbd);
2006 nbd_clear_sock(nbd);
2007 mutex_unlock(&nbd->config_lock);
2008 /*
2009 * Make sure recv thread has finished, so it does not drop the last
2010 * config ref and try to destroy the workqueue from inside the work
2011 * queue.
2012 */
2013 flush_workqueue(nbd->recv_workq);
2014 if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF,
2015 &nbd->config->runtime_flags))
2016 nbd_config_put(nbd);
2017 }
2018
2019 static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info)
2020 {
2021 struct nbd_device *nbd;
2022 int index;
2023
2024 if (!netlink_capable(skb, CAP_SYS_ADMIN))
2025 return -EPERM;
2026
2027 if (!info->attrs[NBD_ATTR_INDEX]) {
2028 printk(KERN_ERR "nbd: must specify an index to disconnect\n");
2029 return -EINVAL;
2030 }
2031 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2032 mutex_lock(&nbd_index_mutex);
2033 nbd = idr_find(&nbd_index_idr, index);
2034 if (!nbd) {
2035 mutex_unlock(&nbd_index_mutex);
2036 printk(KERN_ERR "nbd: couldn't find device at index %d\n",
2037 index);
2038 return -EINVAL;
2039 }
2040 if (!refcount_inc_not_zero(&nbd->refs)) {
2041 mutex_unlock(&nbd_index_mutex);
2042 printk(KERN_ERR "nbd: device at index %d is going down\n",
2043 index);
2044 return -EINVAL;
2045 }
2046 mutex_unlock(&nbd_index_mutex);
2047 if (!refcount_inc_not_zero(&nbd->config_refs)) {
2048 nbd_put(nbd);
2049 return 0;
2050 }
2051 nbd_disconnect_and_put(nbd);
2052 nbd_config_put(nbd);
2053 nbd_put(nbd);
2054 return 0;
2055 }
2056
2057 static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info)
2058 {
2059 struct nbd_device *nbd = NULL;
2060 struct nbd_config *config;
2061 int index;
2062 int ret = 0;
2063 bool put_dev = false;
2064
2065 if (!netlink_capable(skb, CAP_SYS_ADMIN))
2066 return -EPERM;
2067
2068 if (!info->attrs[NBD_ATTR_INDEX]) {
2069 printk(KERN_ERR "nbd: must specify a device to reconfigure\n");
2070 return -EINVAL;
2071 }
2072 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2073 mutex_lock(&nbd_index_mutex);
2074 nbd = idr_find(&nbd_index_idr, index);
2075 if (!nbd) {
2076 mutex_unlock(&nbd_index_mutex);
2077 printk(KERN_ERR "nbd: couldn't find a device at index %d\n",
2078 index);
2079 return -EINVAL;
2080 }
2081 if (!refcount_inc_not_zero(&nbd->refs)) {
2082 mutex_unlock(&nbd_index_mutex);
2083 printk(KERN_ERR "nbd: device at index %d is going down\n",
2084 index);
2085 return -EINVAL;
2086 }
2087 mutex_unlock(&nbd_index_mutex);
2088
2089 if (!refcount_inc_not_zero(&nbd->config_refs)) {
2090 dev_err(nbd_to_dev(nbd),
2091 "not configured, cannot reconfigure\n");
2092 nbd_put(nbd);
2093 return -EINVAL;
2094 }
2095
2096 mutex_lock(&nbd->config_lock);
2097 config = nbd->config;
2098 if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) ||
2099 !nbd->task_recv) {
2100 dev_err(nbd_to_dev(nbd),
2101 "not configured, cannot reconfigure\n");
2102 ret = -EINVAL;
2103 goto out;
2104 }
2105
2106 ret = nbd_genl_size_set(info, nbd);
2107 if (ret)
2108 goto out;
2109
2110 if (info->attrs[NBD_ATTR_TIMEOUT])
2111 nbd_set_cmd_timeout(nbd,
2112 nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]));
2113 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
2114 config->dead_conn_timeout =
2115 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
2116 config->dead_conn_timeout *= HZ;
2117 }
2118 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
2119 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
2120 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
2121 if (!test_and_set_bit(NBD_RT_DESTROY_ON_DISCONNECT,
2122 &config->runtime_flags))
2123 put_dev = true;
2124 set_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags);
2125 } else {
2126 if (test_and_clear_bit(NBD_RT_DESTROY_ON_DISCONNECT,
2127 &config->runtime_flags))
2128 refcount_inc(&nbd->refs);
2129 clear_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags);
2130 }
2131
2132 if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {
2133 set_bit(NBD_RT_DISCONNECT_ON_CLOSE,
2134 &config->runtime_flags);
2135 } else {
2136 clear_bit(NBD_RT_DISCONNECT_ON_CLOSE,
2137 &config->runtime_flags);
2138 }
2139 }
2140
2141 if (info->attrs[NBD_ATTR_SOCKETS]) {
2142 struct nlattr *attr;
2143 int rem, fd;
2144
2145 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
2146 rem) {
2147 struct nlattr *socks[NBD_SOCK_MAX+1];
2148
2149 if (nla_type(attr) != NBD_SOCK_ITEM) {
2150 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");
2151 ret = -EINVAL;
2152 goto out;
2153 }
2154 ret = nla_parse_nested_deprecated(socks, NBD_SOCK_MAX,
2155 attr,
2156 nbd_sock_policy,
2157 info->extack);
2158 if (ret != 0) {
2159 printk(KERN_ERR "nbd: error processing sock list\n");
2160 ret = -EINVAL;
2161 goto out;
2162 }
2163 if (!socks[NBD_SOCK_FD])
2164 continue;
2165 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
2166 ret = nbd_reconnect_socket(nbd, fd);
2167 if (ret) {
2168 if (ret == -ENOSPC)
2169 ret = 0;
2170 goto out;
2171 }
2172 dev_info(nbd_to_dev(nbd), "reconnected socket\n");
2173 }
2174 }
2175 out:
2176 mutex_unlock(&nbd->config_lock);
2177 nbd_config_put(nbd);
2178 nbd_put(nbd);
2179 if (put_dev)
2180 nbd_put(nbd);
2181 return ret;
2182 }
2183
2184 static const struct genl_ops nbd_connect_genl_ops[] = {
2185 {
2186 .cmd = NBD_CMD_CONNECT,
2187 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2188 .doit = nbd_genl_connect,
2189 },
2190 {
2191 .cmd = NBD_CMD_DISCONNECT,
2192 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2193 .doit = nbd_genl_disconnect,
2194 },
2195 {
2196 .cmd = NBD_CMD_RECONFIGURE,
2197 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2198 .doit = nbd_genl_reconfigure,
2199 },
2200 {
2201 .cmd = NBD_CMD_STATUS,
2202 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2203 .doit = nbd_genl_status,
2204 },
2205 };
2206
2207 static const struct genl_multicast_group nbd_mcast_grps[] = {
2208 { .name = NBD_GENL_MCAST_GROUP_NAME, },
2209 };
2210
2211 static struct genl_family nbd_genl_family __ro_after_init = {
2212 .hdrsize = 0,
2213 .name = NBD_GENL_FAMILY_NAME,
2214 .version = NBD_GENL_VERSION,
2215 .module = THIS_MODULE,
2216 .ops = nbd_connect_genl_ops,
2217 .n_ops = ARRAY_SIZE(nbd_connect_genl_ops),
2218 .maxattr = NBD_ATTR_MAX,
2219 .policy = nbd_attr_policy,
2220 .mcgrps = nbd_mcast_grps,
2221 .n_mcgrps = ARRAY_SIZE(nbd_mcast_grps),
2222 };
2223
2224 static int populate_nbd_status(struct nbd_device *nbd, struct sk_buff *reply)
2225 {
2226 struct nlattr *dev_opt;
2227 u8 connected = 0;
2228 int ret;
2229
2230 /* This is a little racey, but for status it's ok. The
2231 * reason we don't take a ref here is because we can't
2232 * take a ref in the index == -1 case as we would need
2233 * to put under the nbd_index_mutex, which could
2234 * deadlock if we are configured to remove ourselves
2235 * once we're disconnected.
2236 */
2237 if (refcount_read(&nbd->config_refs))
2238 connected = 1;
2239 dev_opt = nla_nest_start_noflag(reply, NBD_DEVICE_ITEM);
2240 if (!dev_opt)
2241 return -EMSGSIZE;
2242 ret = nla_put_u32(reply, NBD_DEVICE_INDEX, nbd->index);
2243 if (ret)
2244 return -EMSGSIZE;
2245 ret = nla_put_u8(reply, NBD_DEVICE_CONNECTED,
2246 connected);
2247 if (ret)
2248 return -EMSGSIZE;
2249 nla_nest_end(reply, dev_opt);
2250 return 0;
2251 }
2252
2253 static int status_cb(int id, void *ptr, void *data)
2254 {
2255 struct nbd_device *nbd = ptr;
2256 return populate_nbd_status(nbd, (struct sk_buff *)data);
2257 }
2258
2259 static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info)
2260 {
2261 struct nlattr *dev_list;
2262 struct sk_buff *reply;
2263 void *reply_head;
2264 size_t msg_size;
2265 int index = -1;
2266 int ret = -ENOMEM;
2267
2268 if (info->attrs[NBD_ATTR_INDEX])
2269 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2270
2271 mutex_lock(&nbd_index_mutex);
2272
2273 msg_size = nla_total_size(nla_attr_size(sizeof(u32)) +
2274 nla_attr_size(sizeof(u8)));
2275 msg_size *= (index == -1) ? nbd_total_devices : 1;
2276
2277 reply = genlmsg_new(msg_size, GFP_KERNEL);
2278 if (!reply)
2279 goto out;
2280 reply_head = genlmsg_put_reply(reply, info, &nbd_genl_family, 0,
2281 NBD_CMD_STATUS);
2282 if (!reply_head) {
2283 nlmsg_free(reply);
2284 goto out;
2285 }
2286
2287 dev_list = nla_nest_start_noflag(reply, NBD_ATTR_DEVICE_LIST);
2288 if (index == -1) {
2289 ret = idr_for_each(&nbd_index_idr, &status_cb, reply);
2290 if (ret) {
2291 nlmsg_free(reply);
2292 goto out;
2293 }
2294 } else {
2295 struct nbd_device *nbd;
2296 nbd = idr_find(&nbd_index_idr, index);
2297 if (nbd) {
2298 ret = populate_nbd_status(nbd, reply);
2299 if (ret) {
2300 nlmsg_free(reply);
2301 goto out;
2302 }
2303 }
2304 }
2305 nla_nest_end(reply, dev_list);
2306 genlmsg_end(reply, reply_head);
2307 ret = genlmsg_reply(reply, info);
2308 out:
2309 mutex_unlock(&nbd_index_mutex);
2310 return ret;
2311 }
2312
2313 static void nbd_connect_reply(struct genl_info *info, int index)
2314 {
2315 struct sk_buff *skb;
2316 void *msg_head;
2317 int ret;
2318
2319 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2320 if (!skb)
2321 return;
2322 msg_head = genlmsg_put_reply(skb, info, &nbd_genl_family, 0,
2323 NBD_CMD_CONNECT);
2324 if (!msg_head) {
2325 nlmsg_free(skb);
2326 return;
2327 }
2328 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2329 if (ret) {
2330 nlmsg_free(skb);
2331 return;
2332 }
2333 genlmsg_end(skb, msg_head);
2334 genlmsg_reply(skb, info);
2335 }
2336
2337 static void nbd_mcast_index(int index)
2338 {
2339 struct sk_buff *skb;
2340 void *msg_head;
2341 int ret;
2342
2343 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2344 if (!skb)
2345 return;
2346 msg_head = genlmsg_put(skb, 0, 0, &nbd_genl_family, 0,
2347 NBD_CMD_LINK_DEAD);
2348 if (!msg_head) {
2349 nlmsg_free(skb);
2350 return;
2351 }
2352 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2353 if (ret) {
2354 nlmsg_free(skb);
2355 return;
2356 }
2357 genlmsg_end(skb, msg_head);
2358 genlmsg_multicast(&nbd_genl_family, skb, 0, 0, GFP_KERNEL);
2359 }
2360
2361 static void nbd_dead_link_work(struct work_struct *work)
2362 {
2363 struct link_dead_args *args = container_of(work, struct link_dead_args,
2364 work);
2365 nbd_mcast_index(args->index);
2366 kfree(args);
2367 }
2368
2369 static int __init nbd_init(void)
2370 {
2371 int i;
2372
2373 BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
2374
2375 if (max_part < 0) {
2376 printk(KERN_ERR "nbd: max_part must be >= 0\n");
2377 return -EINVAL;
2378 }
2379
2380 part_shift = 0;
2381 if (max_part > 0) {
2382 part_shift = fls(max_part);
2383
2384 /*
2385 * Adjust max_part according to part_shift as it is exported
2386 * to user space so that user can know the max number of
2387 * partition kernel should be able to manage.
2388 *
2389 * Note that -1 is required because partition 0 is reserved
2390 * for the whole disk.
2391 */
2392 max_part = (1UL << part_shift) - 1;
2393 }
2394
2395 if ((1UL << part_shift) > DISK_MAX_PARTS)
2396 return -EINVAL;
2397
2398 if (nbds_max > 1UL << (MINORBITS - part_shift))
2399 return -EINVAL;
2400
2401 if (register_blkdev(NBD_MAJOR, "nbd"))
2402 return -EIO;
2403
2404 if (genl_register_family(&nbd_genl_family)) {
2405 unregister_blkdev(NBD_MAJOR, "nbd");
2406 return -EINVAL;
2407 }
2408 nbd_dbg_init();
2409
2410 mutex_lock(&nbd_index_mutex);
2411 for (i = 0; i < nbds_max; i++)
2412 nbd_dev_add(i);
2413 mutex_unlock(&nbd_index_mutex);
2414 return 0;
2415 }
2416
2417 static int nbd_exit_cb(int id, void *ptr, void *data)
2418 {
2419 struct list_head *list = (struct list_head *)data;
2420 struct nbd_device *nbd = ptr;
2421
2422 list_add_tail(&nbd->list, list);
2423 return 0;
2424 }
2425
2426 static void __exit nbd_cleanup(void)
2427 {
2428 struct nbd_device *nbd;
2429 LIST_HEAD(del_list);
2430
2431 nbd_dbg_close();
2432
2433 mutex_lock(&nbd_index_mutex);
2434 idr_for_each(&nbd_index_idr, &nbd_exit_cb, &del_list);
2435 mutex_unlock(&nbd_index_mutex);
2436
2437 while (!list_empty(&del_list)) {
2438 nbd = list_first_entry(&del_list, struct nbd_device, list);
2439 list_del_init(&nbd->list);
2440 if (refcount_read(&nbd->refs) != 1)
2441 printk(KERN_ERR "nbd: possibly leaking a device\n");
2442 nbd_put(nbd);
2443 }
2444
2445 idr_destroy(&nbd_index_idr);
2446 genl_unregister_family(&nbd_genl_family);
2447 unregister_blkdev(NBD_MAJOR, "nbd");
2448 }
2449
2450 module_init(nbd_init);
2451 module_exit(nbd_cleanup);
2452
2453 MODULE_DESCRIPTION("Network Block Device");
2454 MODULE_LICENSE("GPL");
2455
2456 module_param(nbds_max, int, 0444);
2457 MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
2458 module_param(max_part, int, 0444);
2459 MODULE_PARM_DESC(max_part, "number of partitions per device (default: 16)");
Linux with added FPC-III support