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serial: tegra: drop bogus NULL tty-port checks
[linux/fpc-iii.git] / drivers / block / nbd.c
blobce7e9f223b20b821e2760f955f6df5bfec8f853e
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
788 while (1) {
789 cmd = nbd_read_stat(nbd, args->index);
790 if (IS_ERR(cmd)) {
791 struct nbd_sock *nsock = config->socks[args->index];
792
793 mutex_lock(&nsock->tx_lock);
794 nbd_mark_nsock_dead(nbd, nsock, 1);
795 mutex_unlock(&nsock->tx_lock);
796 break;
797 }
798
799 blk_mq_complete_request(blk_mq_rq_from_pdu(cmd));
800 }
801 atomic_dec(&config->recv_threads);
802 wake_up(&config->recv_wq);
803 nbd_config_put(nbd);
804 kfree(args);
805 }
806
807 static bool nbd_clear_req(struct request *req, void *data, bool reserved)
808 {
809 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
810
811 mutex_lock(&cmd->lock);
812 cmd->status = BLK_STS_IOERR;
813 mutex_unlock(&cmd->lock);
814
815 blk_mq_complete_request(req);
816 return true;
817 }
818
819 static void nbd_clear_que(struct nbd_device *nbd)
820 {
821 blk_mq_quiesce_queue(nbd->disk->queue);
822 blk_mq_tagset_busy_iter(&nbd->tag_set, nbd_clear_req, NULL);
823 blk_mq_unquiesce_queue(nbd->disk->queue);
824 dev_dbg(disk_to_dev(nbd->disk), "queue cleared\n");
825 }
826
827 static int find_fallback(struct nbd_device *nbd, int index)
828 {
829 struct nbd_config *config = nbd->config;
830 int new_index = -1;
831 struct nbd_sock *nsock = config->socks[index];
832 int fallback = nsock->fallback_index;
833
834 if (test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags))
835 return new_index;
836
837 if (config->num_connections <= 1) {
838 dev_err_ratelimited(disk_to_dev(nbd->disk),
839 "Dead connection, failed to find a fallback\n");
840 return new_index;
841 }
842
843 if (fallback >= 0 && fallback < config->num_connections &&
844 !config->socks[fallback]->dead)
845 return fallback;
846
847 if (nsock->fallback_index < 0 ||
848 nsock->fallback_index >= config->num_connections ||
849 config->socks[nsock->fallback_index]->dead) {
850 int i;
851 for (i = 0; i < config->num_connections; i++) {
852 if (i == index)
853 continue;
854 if (!config->socks[i]->dead) {
855 new_index = i;
856 break;
857 }
858 }
859 nsock->fallback_index = new_index;
860 if (new_index < 0) {
861 dev_err_ratelimited(disk_to_dev(nbd->disk),
862 "Dead connection, failed to find a fallback\n");
863 return new_index;
864 }
865 }
866 new_index = nsock->fallback_index;
867 return new_index;
868 }
869
870 static int wait_for_reconnect(struct nbd_device *nbd)
871 {
872 struct nbd_config *config = nbd->config;
873 if (!config->dead_conn_timeout)
874 return 0;
875 if (test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags))
876 return 0;
877 return wait_event_timeout(config->conn_wait,
878 atomic_read(&config->live_connections) > 0,
879 config->dead_conn_timeout) > 0;
880 }
881
882 static int nbd_handle_cmd(struct nbd_cmd *cmd, int index)
883 {
884 struct request *req = blk_mq_rq_from_pdu(cmd);
885 struct nbd_device *nbd = cmd->nbd;
886 struct nbd_config *config;
887 struct nbd_sock *nsock;
888 int ret;
889
890 if (!refcount_inc_not_zero(&nbd->config_refs)) {
891 dev_err_ratelimited(disk_to_dev(nbd->disk),
892 "Socks array is empty\n");
893 blk_mq_start_request(req);
894 return -EINVAL;
895 }
896 config = nbd->config;
897
898 if (index >= config->num_connections) {
899 dev_err_ratelimited(disk_to_dev(nbd->disk),
900 "Attempted send on invalid socket\n");
901 nbd_config_put(nbd);
902 blk_mq_start_request(req);
903 return -EINVAL;
904 }
905 cmd->status = BLK_STS_OK;
906 again:
907 nsock = config->socks[index];
908 mutex_lock(&nsock->tx_lock);
909 if (nsock->dead) {
910 int old_index = index;
911 index = find_fallback(nbd, index);
912 mutex_unlock(&nsock->tx_lock);
913 if (index < 0) {
914 if (wait_for_reconnect(nbd)) {
915 index = old_index;
916 goto again;
917 }
918 /* All the sockets should already be down at this point,
919 * we just want to make sure that DISCONNECTED is set so
920 * any requests that come in that were queue'ed waiting
921 * for the reconnect timer don't trigger the timer again
922 * and instead just error out.
923 */
924 sock_shutdown(nbd);
925 nbd_config_put(nbd);
926 blk_mq_start_request(req);
927 return -EIO;
928 }
929 goto again;
930 }
931
932 /* Handle the case that we have a pending request that was partially
933 * transmitted that _has_ to be serviced first. We need to call requeue
934 * here so that it gets put _after_ the request that is already on the
935 * dispatch list.
936 */
937 blk_mq_start_request(req);
938 if (unlikely(nsock->pending && nsock->pending != req)) {
939 nbd_requeue_cmd(cmd);
940 ret = 0;
941 goto out;
942 }
943 /*
944 * Some failures are related to the link going down, so anything that
945 * returns EAGAIN can be retried on a different socket.
946 */
947 ret = nbd_send_cmd(nbd, cmd, index);
948 if (ret == -EAGAIN) {
949 dev_err_ratelimited(disk_to_dev(nbd->disk),
950 "Request send failed, requeueing\n");
951 nbd_mark_nsock_dead(nbd, nsock, 1);
952 nbd_requeue_cmd(cmd);
953 ret = 0;
954 }
955 out:
956 mutex_unlock(&nsock->tx_lock);
957 nbd_config_put(nbd);
958 return ret;
959 }
960
961 static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
962 const struct blk_mq_queue_data *bd)
963 {
964 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
965 int ret;
966
967 /*
968 * Since we look at the bio's to send the request over the network we
969 * need to make sure the completion work doesn't mark this request done
970 * before we are done doing our send. This keeps us from dereferencing
971 * freed data if we have particularly fast completions (ie we get the
972 * completion before we exit sock_xmit on the last bvec) or in the case
973 * that the server is misbehaving (or there was an error) before we're
974 * done sending everything over the wire.
975 */
976 mutex_lock(&cmd->lock);
977 clear_bit(NBD_CMD_REQUEUED, &cmd->flags);
978
979 /* We can be called directly from the user space process, which means we
980 * could possibly have signals pending so our sendmsg will fail. In
981 * this case we need to return that we are busy, otherwise error out as
982 * appropriate.
983 */
984 ret = nbd_handle_cmd(cmd, hctx->queue_num);
985 if (ret < 0)
986 ret = BLK_STS_IOERR;
987 else if (!ret)
988 ret = BLK_STS_OK;
989 mutex_unlock(&cmd->lock);
990
991 return ret;
992 }
993
994 static struct socket *nbd_get_socket(struct nbd_device *nbd, unsigned long fd,
995 int *err)
996 {
997 struct socket *sock;
998
999 *err = 0;
1000 sock = sockfd_lookup(fd, err);
1001 if (!sock)
1002 return NULL;
1003
1004 if (sock->ops->shutdown == sock_no_shutdown) {
1005 dev_err(disk_to_dev(nbd->disk), "Unsupported socket: shutdown callout must be supported.\n");
1006 *err = -EINVAL;
1007 sockfd_put(sock);
1008 return NULL;
1009 }
1010
1011 return sock;
1012 }
1013
1014 static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
1015 bool netlink)
1016 {
1017 struct nbd_config *config = nbd->config;
1018 struct socket *sock;
1019 struct nbd_sock **socks;
1020 struct nbd_sock *nsock;
1021 int err;
1022
1023 sock = nbd_get_socket(nbd, arg, &err);
1024 if (!sock)
1025 return err;
1026
1027 if (!netlink && !nbd->task_setup &&
1028 !test_bit(NBD_RT_BOUND, &config->runtime_flags))
1029 nbd->task_setup = current;
1030
1031 if (!netlink &&
1032 (nbd->task_setup != current ||
1033 test_bit(NBD_RT_BOUND, &config->runtime_flags))) {
1034 dev_err(disk_to_dev(nbd->disk),
1035 "Device being setup by another task");
1036 err = -EBUSY;
1037 goto put_socket;
1038 }
1039
1040 nsock = kzalloc(sizeof(*nsock), GFP_KERNEL);
1041 if (!nsock) {
1042 err = -ENOMEM;
1043 goto put_socket;
1044 }
1045
1046 socks = krealloc(config->socks, (config->num_connections + 1) *
1047 sizeof(struct nbd_sock *), GFP_KERNEL);
1048 if (!socks) {
1049 kfree(nsock);
1050 err = -ENOMEM;
1051 goto put_socket;
1052 }
1053
1054 config->socks = socks;
1055
1056 nsock->fallback_index = -1;
1057 nsock->dead = false;
1058 mutex_init(&nsock->tx_lock);
1059 nsock->sock = sock;
1060 nsock->pending = NULL;
1061 nsock->sent = 0;
1062 nsock->cookie = 0;
1063 socks[config->num_connections++] = nsock;
1064 atomic_inc(&config->live_connections);
1065
1066 return 0;
1067
1068 put_socket:
1069 sockfd_put(sock);
1070 return err;
1071 }
1072
1073 static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg)
1074 {
1075 struct nbd_config *config = nbd->config;
1076 struct socket *sock, *old;
1077 struct recv_thread_args *args;
1078 int i;
1079 int err;
1080
1081 sock = nbd_get_socket(nbd, arg, &err);
1082 if (!sock)
1083 return err;
1084
1085 args = kzalloc(sizeof(*args), GFP_KERNEL);
1086 if (!args) {
1087 sockfd_put(sock);
1088 return -ENOMEM;
1089 }
1090
1091 for (i = 0; i < config->num_connections; i++) {
1092 struct nbd_sock *nsock = config->socks[i];
1093
1094 if (!nsock->dead)
1095 continue;
1096
1097 mutex_lock(&nsock->tx_lock);
1098 if (!nsock->dead) {
1099 mutex_unlock(&nsock->tx_lock);
1100 continue;
1101 }
1102 sk_set_memalloc(sock->sk);
1103 if (nbd->tag_set.timeout)
1104 sock->sk->sk_sndtimeo = nbd->tag_set.timeout;
1105 atomic_inc(&config->recv_threads);
1106 refcount_inc(&nbd->config_refs);
1107 old = nsock->sock;
1108 nsock->fallback_index = -1;
1109 nsock->sock = sock;
1110 nsock->dead = false;
1111 INIT_WORK(&args->work, recv_work);
1112 args->index = i;
1113 args->nbd = nbd;
1114 nsock->cookie++;
1115 mutex_unlock(&nsock->tx_lock);
1116 sockfd_put(old);
1117
1118 clear_bit(NBD_RT_DISCONNECTED, &config->runtime_flags);
1119
1120 /* We take the tx_mutex in an error path in the recv_work, so we
1121 * need to queue_work outside of the tx_mutex.
1122 */
1123 queue_work(nbd->recv_workq, &args->work);
1124
1125 atomic_inc(&config->live_connections);
1126 wake_up(&config->conn_wait);
1127 return 0;
1128 }
1129 sockfd_put(sock);
1130 kfree(args);
1131 return -ENOSPC;
1132 }
1133
1134 static void nbd_bdev_reset(struct block_device *bdev)
1135 {
1136 if (bdev->bd_openers > 1)
1137 return;
1138 bd_set_size(bdev, 0);
1139 }
1140
1141 static void nbd_parse_flags(struct nbd_device *nbd)
1142 {
1143 struct nbd_config *config = nbd->config;
1144 if (config->flags & NBD_FLAG_READ_ONLY)
1145 set_disk_ro(nbd->disk, true);
1146 else
1147 set_disk_ro(nbd->disk, false);
1148 if (config->flags & NBD_FLAG_SEND_TRIM)
1149 blk_queue_flag_set(QUEUE_FLAG_DISCARD, nbd->disk->queue);
1150 if (config->flags & NBD_FLAG_SEND_FLUSH) {
1151 if (config->flags & NBD_FLAG_SEND_FUA)
1152 blk_queue_write_cache(nbd->disk->queue, true, true);
1153 else
1154 blk_queue_write_cache(nbd->disk->queue, true, false);
1155 }
1156 else
1157 blk_queue_write_cache(nbd->disk->queue, false, false);
1158 }
1159
1160 static void send_disconnects(struct nbd_device *nbd)
1161 {
1162 struct nbd_config *config = nbd->config;
1163 struct nbd_request request = {
1164 .magic = htonl(NBD_REQUEST_MAGIC),
1165 .type = htonl(NBD_CMD_DISC),
1166 };
1167 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
1168 struct iov_iter from;
1169 int i, ret;
1170
1171 for (i = 0; i < config->num_connections; i++) {
1172 struct nbd_sock *nsock = config->socks[i];
1173
1174 iov_iter_kvec(&from, WRITE, &iov, 1, sizeof(request));
1175 mutex_lock(&nsock->tx_lock);
1176 ret = sock_xmit(nbd, i, 1, &from, 0, NULL);
1177 if (ret <= 0)
1178 dev_err(disk_to_dev(nbd->disk),
1179 "Send disconnect failed %d\n", ret);
1180 mutex_unlock(&nsock->tx_lock);
1181 }
1182 }
1183
1184 static int nbd_disconnect(struct nbd_device *nbd)
1185 {
1186 struct nbd_config *config = nbd->config;
1187
1188 dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
1189 set_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags);
1190 set_bit(NBD_DISCONNECT_REQUESTED, &nbd->flags);
1191 send_disconnects(nbd);
1192 return 0;
1193 }
1194
1195 static void nbd_clear_sock(struct nbd_device *nbd)
1196 {
1197 sock_shutdown(nbd);
1198 nbd_clear_que(nbd);
1199 nbd->task_setup = NULL;
1200 }
1201
1202 static void nbd_config_put(struct nbd_device *nbd)
1203 {
1204 if (refcount_dec_and_mutex_lock(&nbd->config_refs,
1205 &nbd->config_lock)) {
1206 struct nbd_config *config = nbd->config;
1207 nbd_dev_dbg_close(nbd);
1208 nbd_size_clear(nbd);
1209 if (test_and_clear_bit(NBD_RT_HAS_PID_FILE,
1210 &config->runtime_flags))
1211 device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
1212 nbd->task_recv = NULL;
1213 nbd_clear_sock(nbd);
1214 if (config->num_connections) {
1215 int i;
1216 for (i = 0; i < config->num_connections; i++) {
1217 sockfd_put(config->socks[i]->sock);
1218 kfree(config->socks[i]);
1219 }
1220 kfree(config->socks);
1221 }
1222 kfree(nbd->config);
1223 nbd->config = NULL;
1224
1225 if (nbd->recv_workq)
1226 destroy_workqueue(nbd->recv_workq);
1227 nbd->recv_workq = NULL;
1228
1229 nbd->tag_set.timeout = 0;
1230 nbd->disk->queue->limits.discard_granularity = 0;
1231 nbd->disk->queue->limits.discard_alignment = 0;
1232 blk_queue_max_discard_sectors(nbd->disk->queue, UINT_MAX);
1233 blk_queue_flag_clear(QUEUE_FLAG_DISCARD, nbd->disk->queue);
1234
1235 mutex_unlock(&nbd->config_lock);
1236 nbd_put(nbd);
1237 module_put(THIS_MODULE);
1238 }
1239 }
1240
1241 static int nbd_start_device(struct nbd_device *nbd)
1242 {
1243 struct nbd_config *config = nbd->config;
1244 int num_connections = config->num_connections;
1245 int error = 0, i;
1246
1247 if (nbd->task_recv)
1248 return -EBUSY;
1249 if (!config->socks)
1250 return -EINVAL;
1251 if (num_connections > 1 &&
1252 !(config->flags & NBD_FLAG_CAN_MULTI_CONN)) {
1253 dev_err(disk_to_dev(nbd->disk), "server does not support multiple connections per device.\n");
1254 return -EINVAL;
1255 }
1256
1257 nbd->recv_workq = alloc_workqueue("knbd%d-recv",
1258 WQ_MEM_RECLAIM | WQ_HIGHPRI |
1259 WQ_UNBOUND, 0, nbd->index);
1260 if (!nbd->recv_workq) {
1261 dev_err(disk_to_dev(nbd->disk), "Could not allocate knbd recv work queue.\n");
1262 return -ENOMEM;
1263 }
1264
1265 blk_mq_update_nr_hw_queues(&nbd->tag_set, config->num_connections);
1266 nbd->task_recv = current;
1267
1268 nbd_parse_flags(nbd);
1269
1270 error = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
1271 if (error) {
1272 dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n");
1273 return error;
1274 }
1275 set_bit(NBD_RT_HAS_PID_FILE, &config->runtime_flags);
1276
1277 nbd_dev_dbg_init(nbd);
1278 for (i = 0; i < num_connections; i++) {
1279 struct recv_thread_args *args;
1280
1281 args = kzalloc(sizeof(*args), GFP_KERNEL);
1282 if (!args) {
1283 sock_shutdown(nbd);
1284 /*
1285 * If num_connections is m (2 < m),
1286 * and NO.1 ~ NO.n(1 < n < m) kzallocs are successful.
1287 * But NO.(n + 1) failed. We still have n recv threads.
1288 * So, add flush_workqueue here to prevent recv threads
1289 * dropping the last config_refs and trying to destroy
1290 * the workqueue from inside the workqueue.
1291 */
1292 if (i)
1293 flush_workqueue(nbd->recv_workq);
1294 return -ENOMEM;
1295 }
1296 sk_set_memalloc(config->socks[i]->sock->sk);
1297 if (nbd->tag_set.timeout)
1298 config->socks[i]->sock->sk->sk_sndtimeo =
1299 nbd->tag_set.timeout;
1300 atomic_inc(&config->recv_threads);
1301 refcount_inc(&nbd->config_refs);
1302 INIT_WORK(&args->work, recv_work);
1303 args->nbd = nbd;
1304 args->index = i;
1305 queue_work(nbd->recv_workq, &args->work);
1306 }
1307 nbd_size_update(nbd);
1308 return error;
1309 }
1310
1311 static int nbd_start_device_ioctl(struct nbd_device *nbd, struct block_device *bdev)
1312 {
1313 struct nbd_config *config = nbd->config;
1314 int ret;
1315
1316 ret = nbd_start_device(nbd);
1317 if (ret)
1318 return ret;
1319
1320 if (max_part)
1321 bdev->bd_invalidated = 1;
1322 mutex_unlock(&nbd->config_lock);
1323 ret = wait_event_interruptible(config->recv_wq,
1324 atomic_read(&config->recv_threads) == 0);
1325 if (ret)
1326 sock_shutdown(nbd);
1327 flush_workqueue(nbd->recv_workq);
1328
1329 mutex_lock(&nbd->config_lock);
1330 nbd_bdev_reset(bdev);
1331 /* user requested, ignore socket errors */
1332 if (test_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags))
1333 ret = 0;
1334 if (test_bit(NBD_RT_TIMEDOUT, &config->runtime_flags))
1335 ret = -ETIMEDOUT;
1336 return ret;
1337 }
1338
1339 static void nbd_clear_sock_ioctl(struct nbd_device *nbd,
1340 struct block_device *bdev)
1341 {
1342 sock_shutdown(nbd);
1343 __invalidate_device(bdev, true);
1344 nbd_bdev_reset(bdev);
1345 if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF,
1346 &nbd->config->runtime_flags))
1347 nbd_config_put(nbd);
1348 }
1349
1350 static bool nbd_is_valid_blksize(unsigned long blksize)
1351 {
1352 if (!blksize || !is_power_of_2(blksize) || blksize < 512 ||
1353 blksize > PAGE_SIZE)
1354 return false;
1355 return true;
1356 }
1357
1358 static void nbd_set_cmd_timeout(struct nbd_device *nbd, u64 timeout)
1359 {
1360 nbd->tag_set.timeout = timeout * HZ;
1361 if (timeout)
1362 blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ);
1363 }
1364
1365 /* Must be called with config_lock held */
1366 static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
1367 unsigned int cmd, unsigned long arg)
1368 {
1369 struct nbd_config *config = nbd->config;
1370
1371 switch (cmd) {
1372 case NBD_DISCONNECT:
1373 return nbd_disconnect(nbd);
1374 case NBD_CLEAR_SOCK:
1375 nbd_clear_sock_ioctl(nbd, bdev);
1376 return 0;
1377 case NBD_SET_SOCK:
1378 return nbd_add_socket(nbd, arg, false);
1379 case NBD_SET_BLKSIZE:
1380 if (!arg)
1381 arg = NBD_DEF_BLKSIZE;
1382 if (!nbd_is_valid_blksize(arg))
1383 return -EINVAL;
1384 nbd_size_set(nbd, arg,
1385 div_s64(config->bytesize, arg));
1386 return 0;
1387 case NBD_SET_SIZE:
1388 nbd_size_set(nbd, config->blksize,
1389 div_s64(arg, config->blksize));
1390 return 0;
1391 case NBD_SET_SIZE_BLOCKS:
1392 nbd_size_set(nbd, config->blksize, arg);
1393 return 0;
1394 case NBD_SET_TIMEOUT:
1395 nbd_set_cmd_timeout(nbd, arg);
1396 return 0;
1397
1398 case NBD_SET_FLAGS:
1399 config->flags = arg;
1400 return 0;
1401 case NBD_DO_IT:
1402 return nbd_start_device_ioctl(nbd, bdev);
1403 case NBD_CLEAR_QUE:
1404 /*
1405 * This is for compatibility only. The queue is always cleared
1406 * by NBD_DO_IT or NBD_CLEAR_SOCK.
1407 */
1408 return 0;
1409 case NBD_PRINT_DEBUG:
1410 /*
1411 * For compatibility only, we no longer keep a list of
1412 * outstanding requests.
1413 */
1414 return 0;
1415 }
1416 return -ENOTTY;
1417 }
1418
1419 static int nbd_ioctl(struct block_device *bdev, fmode_t mode,
1420 unsigned int cmd, unsigned long arg)
1421 {
1422 struct nbd_device *nbd = bdev->bd_disk->private_data;
1423 struct nbd_config *config = nbd->config;
1424 int error = -EINVAL;
1425
1426 if (!capable(CAP_SYS_ADMIN))
1427 return -EPERM;
1428
1429 /* The block layer will pass back some non-nbd ioctls in case we have
1430 * special handling for them, but we don't so just return an error.
1431 */
1432 if (_IOC_TYPE(cmd) != 0xab)
1433 return -EINVAL;
1434
1435 mutex_lock(&nbd->config_lock);
1436
1437 /* Don't allow ioctl operations on a nbd device that was created with
1438 * netlink, unless it's DISCONNECT or CLEAR_SOCK, which are fine.
1439 */
1440 if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) ||
1441 (cmd == NBD_DISCONNECT || cmd == NBD_CLEAR_SOCK))
1442 error = __nbd_ioctl(bdev, nbd, cmd, arg);
1443 else
1444 dev_err(nbd_to_dev(nbd), "Cannot use ioctl interface on a netlink controlled device.\n");
1445 mutex_unlock(&nbd->config_lock);
1446 return error;
1447 }
1448
1449 static struct nbd_config *nbd_alloc_config(void)
1450 {
1451 struct nbd_config *config;
1452
1453 config = kzalloc(sizeof(struct nbd_config), GFP_NOFS);
1454 if (!config)
1455 return NULL;
1456 atomic_set(&config->recv_threads, 0);
1457 init_waitqueue_head(&config->recv_wq);
1458 init_waitqueue_head(&config->conn_wait);
1459 config->blksize = NBD_DEF_BLKSIZE;
1460 atomic_set(&config->live_connections, 0);
1461 try_module_get(THIS_MODULE);
1462 return config;
1463 }
1464
1465 static int nbd_open(struct block_device *bdev, fmode_t mode)
1466 {
1467 struct nbd_device *nbd;
1468 int ret = 0;
1469
1470 mutex_lock(&nbd_index_mutex);
1471 nbd = bdev->bd_disk->private_data;
1472 if (!nbd) {
1473 ret = -ENXIO;
1474 goto out;
1475 }
1476 if (!refcount_inc_not_zero(&nbd->refs)) {
1477 ret = -ENXIO;
1478 goto out;
1479 }
1480 if (!refcount_inc_not_zero(&nbd->config_refs)) {
1481 struct nbd_config *config;
1482
1483 mutex_lock(&nbd->config_lock);
1484 if (refcount_inc_not_zero(&nbd->config_refs)) {
1485 mutex_unlock(&nbd->config_lock);
1486 goto out;
1487 }
1488 config = nbd->config = nbd_alloc_config();
1489 if (!config) {
1490 ret = -ENOMEM;
1491 mutex_unlock(&nbd->config_lock);
1492 goto out;
1493 }
1494 refcount_set(&nbd->config_refs, 1);
1495 refcount_inc(&nbd->refs);
1496 mutex_unlock(&nbd->config_lock);
1497 bdev->bd_invalidated = 1;
1498 } else if (nbd_disconnected(nbd->config)) {
1499 bdev->bd_invalidated = 1;
1500 }
1501 out:
1502 mutex_unlock(&nbd_index_mutex);
1503 return ret;
1504 }
1505
1506 static void nbd_release(struct gendisk *disk, fmode_t mode)
1507 {
1508 struct nbd_device *nbd = disk->private_data;
1509 struct block_device *bdev = bdget_disk(disk, 0);
1510
1511 if (test_bit(NBD_RT_DISCONNECT_ON_CLOSE, &nbd->config->runtime_flags) &&
1512 bdev->bd_openers == 0)
1513 nbd_disconnect_and_put(nbd);
1514
1515 nbd_config_put(nbd);
1516 nbd_put(nbd);
1517 }
1518
1519 static const struct block_device_operations nbd_fops =
1520 {
1521 .owner = THIS_MODULE,
1522 .open = nbd_open,
1523 .release = nbd_release,
1524 .ioctl = nbd_ioctl,
1525 .compat_ioctl = nbd_ioctl,
1526 };
1527
1528 #if IS_ENABLED(CONFIG_DEBUG_FS)
1529
1530 static int nbd_dbg_tasks_show(struct seq_file *s, void *unused)
1531 {
1532 struct nbd_device *nbd = s->private;
1533
1534 if (nbd->task_recv)
1535 seq_printf(s, "recv: %d\n", task_pid_nr(nbd->task_recv));
1536
1537 return 0;
1538 }
1539
1540 static int nbd_dbg_tasks_open(struct inode *inode, struct file *file)
1541 {
1542 return single_open(file, nbd_dbg_tasks_show, inode->i_private);
1543 }
1544
1545 static const struct file_operations nbd_dbg_tasks_ops = {
1546 .open = nbd_dbg_tasks_open,
1547 .read = seq_read,
1548 .llseek = seq_lseek,
1549 .release = single_release,
1550 };
1551
1552 static int nbd_dbg_flags_show(struct seq_file *s, void *unused)
1553 {
1554 struct nbd_device *nbd = s->private;
1555 u32 flags = nbd->config->flags;
1556
1557 seq_printf(s, "Hex: 0x%08x\n\n", flags);
1558
1559 seq_puts(s, "Known flags:\n");
1560
1561 if (flags & NBD_FLAG_HAS_FLAGS)
1562 seq_puts(s, "NBD_FLAG_HAS_FLAGS\n");
1563 if (flags & NBD_FLAG_READ_ONLY)
1564 seq_puts(s, "NBD_FLAG_READ_ONLY\n");
1565 if (flags & NBD_FLAG_SEND_FLUSH)
1566 seq_puts(s, "NBD_FLAG_SEND_FLUSH\n");
1567 if (flags & NBD_FLAG_SEND_FUA)
1568 seq_puts(s, "NBD_FLAG_SEND_FUA\n");
1569 if (flags & NBD_FLAG_SEND_TRIM)
1570 seq_puts(s, "NBD_FLAG_SEND_TRIM\n");
1571
1572 return 0;
1573 }
1574
1575 static int nbd_dbg_flags_open(struct inode *inode, struct file *file)
1576 {
1577 return single_open(file, nbd_dbg_flags_show, inode->i_private);
1578 }
1579
1580 static const struct file_operations nbd_dbg_flags_ops = {
1581 .open = nbd_dbg_flags_open,
1582 .read = seq_read,
1583 .llseek = seq_lseek,
1584 .release = single_release,
1585 };
1586
1587 static int nbd_dev_dbg_init(struct nbd_device *nbd)
1588 {
1589 struct dentry *dir;
1590 struct nbd_config *config = nbd->config;
1591
1592 if (!nbd_dbg_dir)
1593 return -EIO;
1594
1595 dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir);
1596 if (!dir) {
1597 dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s'\n",
1598 nbd_name(nbd));
1599 return -EIO;
1600 }
1601 config->dbg_dir = dir;
1602
1603 debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_ops);
1604 debugfs_create_u64("size_bytes", 0444, dir, &config->bytesize);
1605 debugfs_create_u32("timeout", 0444, dir, &nbd->tag_set.timeout);
1606 debugfs_create_u64("blocksize", 0444, dir, &config->blksize);
1607 debugfs_create_file("flags", 0444, dir, nbd, &nbd_dbg_flags_ops);
1608
1609 return 0;
1610 }
1611
1612 static void nbd_dev_dbg_close(struct nbd_device *nbd)
1613 {
1614 debugfs_remove_recursive(nbd->config->dbg_dir);
1615 }
1616
1617 static int nbd_dbg_init(void)
1618 {
1619 struct dentry *dbg_dir;
1620
1621 dbg_dir = debugfs_create_dir("nbd", NULL);
1622 if (!dbg_dir)
1623 return -EIO;
1624
1625 nbd_dbg_dir = dbg_dir;
1626
1627 return 0;
1628 }
1629
1630 static void nbd_dbg_close(void)
1631 {
1632 debugfs_remove_recursive(nbd_dbg_dir);
1633 }
1634
1635 #else /* IS_ENABLED(CONFIG_DEBUG_FS) */
1636
1637 static int nbd_dev_dbg_init(struct nbd_device *nbd)
1638 {
1639 return 0;
1640 }
1641
1642 static void nbd_dev_dbg_close(struct nbd_device *nbd)
1643 {
1644 }
1645
1646 static int nbd_dbg_init(void)
1647 {
1648 return 0;
1649 }
1650
1651 static void nbd_dbg_close(void)
1652 {
1653 }
1654
1655 #endif
1656
1657 static int nbd_init_request(struct blk_mq_tag_set *set, struct request *rq,
1658 unsigned int hctx_idx, unsigned int numa_node)
1659 {
1660 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq);
1661 cmd->nbd = set->driver_data;
1662 cmd->flags = 0;
1663 mutex_init(&cmd->lock);
1664 return 0;
1665 }
1666
1667 static const struct blk_mq_ops nbd_mq_ops = {
1668 .queue_rq = nbd_queue_rq,
1669 .complete = nbd_complete_rq,
1670 .init_request = nbd_init_request,
1671 .timeout = nbd_xmit_timeout,
1672 };
1673
1674 static int nbd_dev_add(int index)
1675 {
1676 struct nbd_device *nbd;
1677 struct gendisk *disk;
1678 struct request_queue *q;
1679 int err = -ENOMEM;
1680
1681 nbd = kzalloc(sizeof(struct nbd_device), GFP_KERNEL);
1682 if (!nbd)
1683 goto out;
1684
1685 disk = alloc_disk(1 << part_shift);
1686 if (!disk)
1687 goto out_free_nbd;
1688
1689 if (index >= 0) {
1690 err = idr_alloc(&nbd_index_idr, nbd, index, index + 1,
1691 GFP_KERNEL);
1692 if (err == -ENOSPC)
1693 err = -EEXIST;
1694 } else {
1695 err = idr_alloc(&nbd_index_idr, nbd, 0, 0, GFP_KERNEL);
1696 if (err >= 0)
1697 index = err;
1698 }
1699 if (err < 0)
1700 goto out_free_disk;
1701
1702 nbd->index = index;
1703 nbd->disk = disk;
1704 nbd->tag_set.ops = &nbd_mq_ops;
1705 nbd->tag_set.nr_hw_queues = 1;
1706 nbd->tag_set.queue_depth = 128;
1707 nbd->tag_set.numa_node = NUMA_NO_NODE;
1708 nbd->tag_set.cmd_size = sizeof(struct nbd_cmd);
1709 nbd->tag_set.flags = BLK_MQ_F_SHOULD_MERGE |
1710 BLK_MQ_F_BLOCKING;
1711 nbd->tag_set.driver_data = nbd;
1712 nbd->destroy_complete = NULL;
1713
1714 err = blk_mq_alloc_tag_set(&nbd->tag_set);
1715 if (err)
1716 goto out_free_idr;
1717
1718 q = blk_mq_init_queue(&nbd->tag_set);
1719 if (IS_ERR(q)) {
1720 err = PTR_ERR(q);
1721 goto out_free_tags;
1722 }
1723 disk->queue = q;
1724
1725 /*
1726 * Tell the block layer that we are not a rotational device
1727 */
1728 blk_queue_flag_set(QUEUE_FLAG_NONROT, disk->queue);
1729 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, disk->queue);
1730 disk->queue->limits.discard_granularity = 0;
1731 disk->queue->limits.discard_alignment = 0;
1732 blk_queue_max_discard_sectors(disk->queue, 0);
1733 blk_queue_max_segment_size(disk->queue, UINT_MAX);
1734 blk_queue_max_segments(disk->queue, USHRT_MAX);
1735 blk_queue_max_hw_sectors(disk->queue, 65536);
1736 disk->queue->limits.max_sectors = 256;
1737
1738 mutex_init(&nbd->config_lock);
1739 refcount_set(&nbd->config_refs, 0);
1740 refcount_set(&nbd->refs, 1);
1741 INIT_LIST_HEAD(&nbd->list);
1742 disk->major = NBD_MAJOR;
1743 disk->first_minor = index << part_shift;
1744 disk->fops = &nbd_fops;
1745 disk->private_data = nbd;
1746 sprintf(disk->disk_name, "nbd%d", index);
1747 add_disk(disk);
1748 nbd_total_devices++;
1749 return index;
1750
1751 out_free_tags:
1752 blk_mq_free_tag_set(&nbd->tag_set);
1753 out_free_idr:
1754 idr_remove(&nbd_index_idr, index);
1755 out_free_disk:
1756 put_disk(disk);
1757 out_free_nbd:
1758 kfree(nbd);
1759 out:
1760 return err;
1761 }
1762
1763 static int find_free_cb(int id, void *ptr, void *data)
1764 {
1765 struct nbd_device *nbd = ptr;
1766 struct nbd_device **found = data;
1767
1768 if (!refcount_read(&nbd->config_refs)) {
1769 *found = nbd;
1770 return 1;
1771 }
1772 return 0;
1773 }
1774
1775 /* Netlink interface. */
1776 static const struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = {
1777 [NBD_ATTR_INDEX] = { .type = NLA_U32 },
1778 [NBD_ATTR_SIZE_BYTES] = { .type = NLA_U64 },
1779 [NBD_ATTR_BLOCK_SIZE_BYTES] = { .type = NLA_U64 },
1780 [NBD_ATTR_TIMEOUT] = { .type = NLA_U64 },
1781 [NBD_ATTR_SERVER_FLAGS] = { .type = NLA_U64 },
1782 [NBD_ATTR_CLIENT_FLAGS] = { .type = NLA_U64 },
1783 [NBD_ATTR_SOCKETS] = { .type = NLA_NESTED},
1784 [NBD_ATTR_DEAD_CONN_TIMEOUT] = { .type = NLA_U64 },
1785 [NBD_ATTR_DEVICE_LIST] = { .type = NLA_NESTED},
1786 };
1787
1788 static const struct nla_policy nbd_sock_policy[NBD_SOCK_MAX + 1] = {
1789 [NBD_SOCK_FD] = { .type = NLA_U32 },
1790 };
1791
1792 /* We don't use this right now since we don't parse the incoming list, but we
1793 * still want it here so userspace knows what to expect.
1794 */
1795 static const struct nla_policy __attribute__((unused))
1796 nbd_device_policy[NBD_DEVICE_ATTR_MAX + 1] = {
1797 [NBD_DEVICE_INDEX] = { .type = NLA_U32 },
1798 [NBD_DEVICE_CONNECTED] = { .type = NLA_U8 },
1799 };
1800
1801 static int nbd_genl_size_set(struct genl_info *info, struct nbd_device *nbd)
1802 {
1803 struct nbd_config *config = nbd->config;
1804 u64 bsize = config->blksize;
1805 u64 bytes = config->bytesize;
1806
1807 if (info->attrs[NBD_ATTR_SIZE_BYTES])
1808 bytes = nla_get_u64(info->attrs[NBD_ATTR_SIZE_BYTES]);
1809
1810 if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]) {
1811 bsize = nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]);
1812 if (!bsize)
1813 bsize = NBD_DEF_BLKSIZE;
1814 if (!nbd_is_valid_blksize(bsize)) {
1815 printk(KERN_ERR "Invalid block size %llu\n", bsize);
1816 return -EINVAL;
1817 }
1818 }
1819
1820 if (bytes != config->bytesize || bsize != config->blksize)
1821 nbd_size_set(nbd, bsize, div64_u64(bytes, bsize));
1822 return 0;
1823 }
1824
1825 static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
1826 {
1827 DECLARE_COMPLETION_ONSTACK(destroy_complete);
1828 struct nbd_device *nbd = NULL;
1829 struct nbd_config *config;
1830 int index = -1;
1831 int ret;
1832 bool put_dev = false;
1833
1834 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1835 return -EPERM;
1836
1837 if (info->attrs[NBD_ATTR_INDEX])
1838 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1839 if (!info->attrs[NBD_ATTR_SOCKETS]) {
1840 printk(KERN_ERR "nbd: must specify at least one socket\n");
1841 return -EINVAL;
1842 }
1843 if (!info->attrs[NBD_ATTR_SIZE_BYTES]) {
1844 printk(KERN_ERR "nbd: must specify a size in bytes for the device\n");
1845 return -EINVAL;
1846 }
1847 again:
1848 mutex_lock(&nbd_index_mutex);
1849 if (index == -1) {
1850 ret = idr_for_each(&nbd_index_idr, &find_free_cb, &nbd);
1851 if (ret == 0) {
1852 int new_index;
1853 new_index = nbd_dev_add(-1);
1854 if (new_index < 0) {
1855 mutex_unlock(&nbd_index_mutex);
1856 printk(KERN_ERR "nbd: failed to add new device\n");
1857 return new_index;
1858 }
1859 nbd = idr_find(&nbd_index_idr, new_index);
1860 }
1861 } else {
1862 nbd = idr_find(&nbd_index_idr, index);
1863 if (!nbd) {
1864 ret = nbd_dev_add(index);
1865 if (ret < 0) {
1866 mutex_unlock(&nbd_index_mutex);
1867 printk(KERN_ERR "nbd: failed to add new device\n");
1868 return ret;
1869 }
1870 nbd = idr_find(&nbd_index_idr, index);
1871 }
1872 }
1873 if (!nbd) {
1874 printk(KERN_ERR "nbd: couldn't find device at index %d\n",
1875 index);
1876 mutex_unlock(&nbd_index_mutex);
1877 return -EINVAL;
1878 }
1879
1880 if (test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags) &&
1881 test_bit(NBD_DISCONNECT_REQUESTED, &nbd->flags)) {
1882 nbd->destroy_complete = &destroy_complete;
1883 mutex_unlock(&nbd_index_mutex);
1884
1885 /* Wait untill the the nbd stuff is totally destroyed */
1886 wait_for_completion(&destroy_complete);
1887 goto again;
1888 }
1889
1890 if (!refcount_inc_not_zero(&nbd->refs)) {
1891 mutex_unlock(&nbd_index_mutex);
1892 if (index == -1)
1893 goto again;
1894 printk(KERN_ERR "nbd: device at index %d is going down\n",
1895 index);
1896 return -EINVAL;
1897 }
1898 mutex_unlock(&nbd_index_mutex);
1899
1900 mutex_lock(&nbd->config_lock);
1901 if (refcount_read(&nbd->config_refs)) {
1902 mutex_unlock(&nbd->config_lock);
1903 nbd_put(nbd);
1904 if (index == -1)
1905 goto again;
1906 printk(KERN_ERR "nbd: nbd%d already in use\n", index);
1907 return -EBUSY;
1908 }
1909 if (WARN_ON(nbd->config)) {
1910 mutex_unlock(&nbd->config_lock);
1911 nbd_put(nbd);
1912 return -EINVAL;
1913 }
1914 config = nbd->config = nbd_alloc_config();
1915 if (!nbd->config) {
1916 mutex_unlock(&nbd->config_lock);
1917 nbd_put(nbd);
1918 printk(KERN_ERR "nbd: couldn't allocate config\n");
1919 return -ENOMEM;
1920 }
1921 refcount_set(&nbd->config_refs, 1);
1922 set_bit(NBD_RT_BOUND, &config->runtime_flags);
1923
1924 ret = nbd_genl_size_set(info, nbd);
1925 if (ret)
1926 goto out;
1927
1928 if (info->attrs[NBD_ATTR_TIMEOUT])
1929 nbd_set_cmd_timeout(nbd,
1930 nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]));
1931 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
1932 config->dead_conn_timeout =
1933 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
1934 config->dead_conn_timeout *= HZ;
1935 }
1936 if (info->attrs[NBD_ATTR_SERVER_FLAGS])
1937 config->flags =
1938 nla_get_u64(info->attrs[NBD_ATTR_SERVER_FLAGS]);
1939 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
1940 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
1941 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
1942 set_bit(NBD_RT_DESTROY_ON_DISCONNECT,
1943 &config->runtime_flags);
1944 set_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags);
1945 put_dev = true;
1946 } else {
1947 clear_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags);
1948 }
1949 if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {
1950 set_bit(NBD_RT_DISCONNECT_ON_CLOSE,
1951 &config->runtime_flags);
1952 }
1953 }
1954
1955 if (info->attrs[NBD_ATTR_SOCKETS]) {
1956 struct nlattr *attr;
1957 int rem, fd;
1958
1959 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
1960 rem) {
1961 struct nlattr *socks[NBD_SOCK_MAX+1];
1962
1963 if (nla_type(attr) != NBD_SOCK_ITEM) {
1964 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");
1965 ret = -EINVAL;
1966 goto out;
1967 }
1968 ret = nla_parse_nested_deprecated(socks, NBD_SOCK_MAX,
1969 attr,
1970 nbd_sock_policy,
1971 info->extack);
1972 if (ret != 0) {
1973 printk(KERN_ERR "nbd: error processing sock list\n");
1974 ret = -EINVAL;
1975 goto out;
1976 }
1977 if (!socks[NBD_SOCK_FD])
1978 continue;
1979 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
1980 ret = nbd_add_socket(nbd, fd, true);
1981 if (ret)
1982 goto out;
1983 }
1984 }
1985 ret = nbd_start_device(nbd);
1986 out:
1987 mutex_unlock(&nbd->config_lock);
1988 if (!ret) {
1989 set_bit(NBD_RT_HAS_CONFIG_REF, &config->runtime_flags);
1990 refcount_inc(&nbd->config_refs);
1991 nbd_connect_reply(info, nbd->index);
1992 }
1993 nbd_config_put(nbd);
1994 if (put_dev)
1995 nbd_put(nbd);
1996 return ret;
1997 }
1998
1999 static void nbd_disconnect_and_put(struct nbd_device *nbd)
2000 {
2001 mutex_lock(&nbd->config_lock);
2002 nbd_disconnect(nbd);
2003 nbd_clear_sock(nbd);
2004 mutex_unlock(&nbd->config_lock);
2005 /*
2006 * Make sure recv thread has finished, so it does not drop the last
2007 * config ref and try to destroy the workqueue from inside the work
2008 * queue.
2009 */
2010 flush_workqueue(nbd->recv_workq);
2011 if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF,
2012 &nbd->config->runtime_flags))
2013 nbd_config_put(nbd);
2014 }
2015
2016 static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info)
2017 {
2018 struct nbd_device *nbd;
2019 int index;
2020
2021 if (!netlink_capable(skb, CAP_SYS_ADMIN))
2022 return -EPERM;
2023
2024 if (!info->attrs[NBD_ATTR_INDEX]) {
2025 printk(KERN_ERR "nbd: must specify an index to disconnect\n");
2026 return -EINVAL;
2027 }
2028 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2029 mutex_lock(&nbd_index_mutex);
2030 nbd = idr_find(&nbd_index_idr, index);
2031 if (!nbd) {
2032 mutex_unlock(&nbd_index_mutex);
2033 printk(KERN_ERR "nbd: couldn't find device at index %d\n",
2034 index);
2035 return -EINVAL;
2036 }
2037 if (!refcount_inc_not_zero(&nbd->refs)) {
2038 mutex_unlock(&nbd_index_mutex);
2039 printk(KERN_ERR "nbd: device at index %d is going down\n",
2040 index);
2041 return -EINVAL;
2042 }
2043 mutex_unlock(&nbd_index_mutex);
2044 if (!refcount_inc_not_zero(&nbd->config_refs)) {
2045 nbd_put(nbd);
2046 return 0;
2047 }
2048 nbd_disconnect_and_put(nbd);
2049 nbd_config_put(nbd);
2050 nbd_put(nbd);
2051 return 0;
2052 }
2053
2054 static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info)
2055 {
2056 struct nbd_device *nbd = NULL;
2057 struct nbd_config *config;
2058 int index;
2059 int ret = 0;
2060 bool put_dev = false;
2061
2062 if (!netlink_capable(skb, CAP_SYS_ADMIN))
2063 return -EPERM;
2064
2065 if (!info->attrs[NBD_ATTR_INDEX]) {
2066 printk(KERN_ERR "nbd: must specify a device to reconfigure\n");
2067 return -EINVAL;
2068 }
2069 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2070 mutex_lock(&nbd_index_mutex);
2071 nbd = idr_find(&nbd_index_idr, index);
2072 if (!nbd) {
2073 mutex_unlock(&nbd_index_mutex);
2074 printk(KERN_ERR "nbd: couldn't find a device at index %d\n",
2075 index);
2076 return -EINVAL;
2077 }
2078 if (!refcount_inc_not_zero(&nbd->refs)) {
2079 mutex_unlock(&nbd_index_mutex);
2080 printk(KERN_ERR "nbd: device at index %d is going down\n",
2081 index);
2082 return -EINVAL;
2083 }
2084 mutex_unlock(&nbd_index_mutex);
2085
2086 if (!refcount_inc_not_zero(&nbd->config_refs)) {
2087 dev_err(nbd_to_dev(nbd),
2088 "not configured, cannot reconfigure\n");
2089 nbd_put(nbd);
2090 return -EINVAL;
2091 }
2092
2093 mutex_lock(&nbd->config_lock);
2094 config = nbd->config;
2095 if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) ||
2096 !nbd->task_recv) {
2097 dev_err(nbd_to_dev(nbd),
2098 "not configured, cannot reconfigure\n");
2099 ret = -EINVAL;
2100 goto out;
2101 }
2102
2103 ret = nbd_genl_size_set(info, nbd);
2104 if (ret)
2105 goto out;
2106
2107 if (info->attrs[NBD_ATTR_TIMEOUT])
2108 nbd_set_cmd_timeout(nbd,
2109 nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]));
2110 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
2111 config->dead_conn_timeout =
2112 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
2113 config->dead_conn_timeout *= HZ;
2114 }
2115 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
2116 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
2117 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
2118 if (!test_and_set_bit(NBD_RT_DESTROY_ON_DISCONNECT,
2119 &config->runtime_flags))
2120 put_dev = true;
2121 set_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags);
2122 } else {
2123 if (test_and_clear_bit(NBD_RT_DESTROY_ON_DISCONNECT,
2124 &config->runtime_flags))
2125 refcount_inc(&nbd->refs);
2126 clear_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags);
2127 }
2128
2129 if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {
2130 set_bit(NBD_RT_DISCONNECT_ON_CLOSE,
2131 &config->runtime_flags);
2132 } else {
2133 clear_bit(NBD_RT_DISCONNECT_ON_CLOSE,
2134 &config->runtime_flags);
2135 }
2136 }
2137
2138 if (info->attrs[NBD_ATTR_SOCKETS]) {
2139 struct nlattr *attr;
2140 int rem, fd;
2141
2142 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
2143 rem) {
2144 struct nlattr *socks[NBD_SOCK_MAX+1];
2145
2146 if (nla_type(attr) != NBD_SOCK_ITEM) {
2147 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");
2148 ret = -EINVAL;
2149 goto out;
2150 }
2151 ret = nla_parse_nested_deprecated(socks, NBD_SOCK_MAX,
2152 attr,
2153 nbd_sock_policy,
2154 info->extack);
2155 if (ret != 0) {
2156 printk(KERN_ERR "nbd: error processing sock list\n");
2157 ret = -EINVAL;
2158 goto out;
2159 }
2160 if (!socks[NBD_SOCK_FD])
2161 continue;
2162 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
2163 ret = nbd_reconnect_socket(nbd, fd);
2164 if (ret) {
2165 if (ret == -ENOSPC)
2166 ret = 0;
2167 goto out;
2168 }
2169 dev_info(nbd_to_dev(nbd), "reconnected socket\n");
2170 }
2171 }
2172 out:
2173 mutex_unlock(&nbd->config_lock);
2174 nbd_config_put(nbd);
2175 nbd_put(nbd);
2176 if (put_dev)
2177 nbd_put(nbd);
2178 return ret;
2179 }
2180
2181 static const struct genl_ops nbd_connect_genl_ops[] = {
2182 {
2183 .cmd = NBD_CMD_CONNECT,
2184 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2185 .doit = nbd_genl_connect,
2186 },
2187 {
2188 .cmd = NBD_CMD_DISCONNECT,
2189 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2190 .doit = nbd_genl_disconnect,
2191 },
2192 {
2193 .cmd = NBD_CMD_RECONFIGURE,
2194 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2195 .doit = nbd_genl_reconfigure,
2196 },
2197 {
2198 .cmd = NBD_CMD_STATUS,
2199 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2200 .doit = nbd_genl_status,
2201 },
2202 };
2203
2204 static const struct genl_multicast_group nbd_mcast_grps[] = {
2205 { .name = NBD_GENL_MCAST_GROUP_NAME, },
2206 };
2207
2208 static struct genl_family nbd_genl_family __ro_after_init = {
2209 .hdrsize = 0,
2210 .name = NBD_GENL_FAMILY_NAME,
2211 .version = NBD_GENL_VERSION,
2212 .module = THIS_MODULE,
2213 .ops = nbd_connect_genl_ops,
2214 .n_ops = ARRAY_SIZE(nbd_connect_genl_ops),
2215 .maxattr = NBD_ATTR_MAX,
2216 .policy = nbd_attr_policy,
2217 .mcgrps = nbd_mcast_grps,
2218 .n_mcgrps = ARRAY_SIZE(nbd_mcast_grps),
2219 };
2220
2221 static int populate_nbd_status(struct nbd_device *nbd, struct sk_buff *reply)
2222 {
2223 struct nlattr *dev_opt;
2224 u8 connected = 0;
2225 int ret;
2226
2227 /* This is a little racey, but for status it's ok. The
2228 * reason we don't take a ref here is because we can't
2229 * take a ref in the index == -1 case as we would need
2230 * to put under the nbd_index_mutex, which could
2231 * deadlock if we are configured to remove ourselves
2232 * once we're disconnected.
2233 */
2234 if (refcount_read(&nbd->config_refs))
2235 connected = 1;
2236 dev_opt = nla_nest_start_noflag(reply, NBD_DEVICE_ITEM);
2237 if (!dev_opt)
2238 return -EMSGSIZE;
2239 ret = nla_put_u32(reply, NBD_DEVICE_INDEX, nbd->index);
2240 if (ret)
2241 return -EMSGSIZE;
2242 ret = nla_put_u8(reply, NBD_DEVICE_CONNECTED,
2243 connected);
2244 if (ret)
2245 return -EMSGSIZE;
2246 nla_nest_end(reply, dev_opt);
2247 return 0;
2248 }
2249
2250 static int status_cb(int id, void *ptr, void *data)
2251 {
2252 struct nbd_device *nbd = ptr;
2253 return populate_nbd_status(nbd, (struct sk_buff *)data);
2254 }
2255
2256 static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info)
2257 {
2258 struct nlattr *dev_list;
2259 struct sk_buff *reply;
2260 void *reply_head;
2261 size_t msg_size;
2262 int index = -1;
2263 int ret = -ENOMEM;
2264
2265 if (info->attrs[NBD_ATTR_INDEX])
2266 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2267
2268 mutex_lock(&nbd_index_mutex);
2269
2270 msg_size = nla_total_size(nla_attr_size(sizeof(u32)) +
2271 nla_attr_size(sizeof(u8)));
2272 msg_size *= (index == -1) ? nbd_total_devices : 1;
2273
2274 reply = genlmsg_new(msg_size, GFP_KERNEL);
2275 if (!reply)
2276 goto out;
2277 reply_head = genlmsg_put_reply(reply, info, &nbd_genl_family, 0,
2278 NBD_CMD_STATUS);
2279 if (!reply_head) {
2280 nlmsg_free(reply);
2281 goto out;
2282 }
2283
2284 dev_list = nla_nest_start_noflag(reply, NBD_ATTR_DEVICE_LIST);
2285 if (index == -1) {
2286 ret = idr_for_each(&nbd_index_idr, &status_cb, reply);
2287 if (ret) {
2288 nlmsg_free(reply);
2289 goto out;
2290 }
2291 } else {
2292 struct nbd_device *nbd;
2293 nbd = idr_find(&nbd_index_idr, index);
2294 if (nbd) {
2295 ret = populate_nbd_status(nbd, reply);
2296 if (ret) {
2297 nlmsg_free(reply);
2298 goto out;
2299 }
2300 }
2301 }
2302 nla_nest_end(reply, dev_list);
2303 genlmsg_end(reply, reply_head);
2304 ret = genlmsg_reply(reply, info);
2305 out:
2306 mutex_unlock(&nbd_index_mutex);
2307 return ret;
2308 }
2309
2310 static void nbd_connect_reply(struct genl_info *info, int index)
2311 {
2312 struct sk_buff *skb;
2313 void *msg_head;
2314 int ret;
2315
2316 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2317 if (!skb)
2318 return;
2319 msg_head = genlmsg_put_reply(skb, info, &nbd_genl_family, 0,
2320 NBD_CMD_CONNECT);
2321 if (!msg_head) {
2322 nlmsg_free(skb);
2323 return;
2324 }
2325 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2326 if (ret) {
2327 nlmsg_free(skb);
2328 return;
2329 }
2330 genlmsg_end(skb, msg_head);
2331 genlmsg_reply(skb, info);
2332 }
2333
2334 static void nbd_mcast_index(int index)
2335 {
2336 struct sk_buff *skb;
2337 void *msg_head;
2338 int ret;
2339
2340 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2341 if (!skb)
2342 return;
2343 msg_head = genlmsg_put(skb, 0, 0, &nbd_genl_family, 0,
2344 NBD_CMD_LINK_DEAD);
2345 if (!msg_head) {
2346 nlmsg_free(skb);
2347 return;
2348 }
2349 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2350 if (ret) {
2351 nlmsg_free(skb);
2352 return;
2353 }
2354 genlmsg_end(skb, msg_head);
2355 genlmsg_multicast(&nbd_genl_family, skb, 0, 0, GFP_KERNEL);
2356 }
2357
2358 static void nbd_dead_link_work(struct work_struct *work)
2359 {
2360 struct link_dead_args *args = container_of(work, struct link_dead_args,
2361 work);
2362 nbd_mcast_index(args->index);
2363 kfree(args);
2364 }
2365
2366 static int __init nbd_init(void)
2367 {
2368 int i;
2369
2370 BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
2371
2372 if (max_part < 0) {
2373 printk(KERN_ERR "nbd: max_part must be >= 0\n");
2374 return -EINVAL;
2375 }
2376
2377 part_shift = 0;
2378 if (max_part > 0) {
2379 part_shift = fls(max_part);
2380
2381 /*
2382 * Adjust max_part according to part_shift as it is exported
2383 * to user space so that user can know the max number of
2384 * partition kernel should be able to manage.
2385 *
2386 * Note that -1 is required because partition 0 is reserved
2387 * for the whole disk.
2388 */
2389 max_part = (1UL << part_shift) - 1;
2390 }
2391
2392 if ((1UL << part_shift) > DISK_MAX_PARTS)
2393 return -EINVAL;
2394
2395 if (nbds_max > 1UL << (MINORBITS - part_shift))
2396 return -EINVAL;
2397
2398 if (register_blkdev(NBD_MAJOR, "nbd"))
2399 return -EIO;
2400
2401 if (genl_register_family(&nbd_genl_family)) {
2402 unregister_blkdev(NBD_MAJOR, "nbd");
2403 return -EINVAL;
2404 }
2405 nbd_dbg_init();
2406
2407 mutex_lock(&nbd_index_mutex);
2408 for (i = 0; i < nbds_max; i++)
2409 nbd_dev_add(i);
2410 mutex_unlock(&nbd_index_mutex);
2411 return 0;
2412 }
2413
2414 static int nbd_exit_cb(int id, void *ptr, void *data)
2415 {
2416 struct list_head *list = (struct list_head *)data;
2417 struct nbd_device *nbd = ptr;
2418
2419 list_add_tail(&nbd->list, list);
2420 return 0;
2421 }
2422
2423 static void __exit nbd_cleanup(void)
2424 {
2425 struct nbd_device *nbd;
2426 LIST_HEAD(del_list);
2427
2428 nbd_dbg_close();
2429
2430 mutex_lock(&nbd_index_mutex);
2431 idr_for_each(&nbd_index_idr, &nbd_exit_cb, &del_list);
2432 mutex_unlock(&nbd_index_mutex);
2433
2434 while (!list_empty(&del_list)) {
2435 nbd = list_first_entry(&del_list, struct nbd_device, list);
2436 list_del_init(&nbd->list);
2437 if (refcount_read(&nbd->refs) != 1)
2438 printk(KERN_ERR "nbd: possibly leaking a device\n");
2439 nbd_put(nbd);
2440 }
2441
2442 idr_destroy(&nbd_index_idr);
2443 genl_unregister_family(&nbd_genl_family);
2444 unregister_blkdev(NBD_MAJOR, "nbd");
2445 }
2446
2447 module_init(nbd_init);
2448 module_exit(nbd_cleanup);
2449
2450 MODULE_DESCRIPTION("Network Block Device");
2451 MODULE_LICENSE("GPL");
2452
2453 module_param(nbds_max, int, 0444);
2454 MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
2455 module_param(max_part, int, 0444);
2456 MODULE_PARM_DESC(max_part, "number of partitions per device (default: 16)");
Linux with added FPC-III support