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gpio: rcar: Fix runtime PM imbalance on error
[linux/fpc-iii.git] / drivers / block / nbd.c
blob43cff01a5a675d47cd9bcb60ffcf1440ac8fc871
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 sockfd_put(sock);
1037 return -EBUSY;
1038 }
1039
1040 socks = krealloc(config->socks, (config->num_connections + 1) *
1041 sizeof(struct nbd_sock *), GFP_KERNEL);
1042 if (!socks) {
1043 sockfd_put(sock);
1044 return -ENOMEM;
1045 }
1046
1047 config->socks = socks;
1048
1049 nsock = kzalloc(sizeof(struct nbd_sock), GFP_KERNEL);
1050 if (!nsock) {
1051 sockfd_put(sock);
1052 return -ENOMEM;
1053 }
1054
1055 nsock->fallback_index = -1;
1056 nsock->dead = false;
1057 mutex_init(&nsock->tx_lock);
1058 nsock->sock = sock;
1059 nsock->pending = NULL;
1060 nsock->sent = 0;
1061 nsock->cookie = 0;
1062 socks[config->num_connections++] = nsock;
1063 atomic_inc(&config->live_connections);
1064
1065 return 0;
1066 }
1067
1068 static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg)
1069 {
1070 struct nbd_config *config = nbd->config;
1071 struct socket *sock, *old;
1072 struct recv_thread_args *args;
1073 int i;
1074 int err;
1075
1076 sock = nbd_get_socket(nbd, arg, &err);
1077 if (!sock)
1078 return err;
1079
1080 args = kzalloc(sizeof(*args), GFP_KERNEL);
1081 if (!args) {
1082 sockfd_put(sock);
1083 return -ENOMEM;
1084 }
1085
1086 for (i = 0; i < config->num_connections; i++) {
1087 struct nbd_sock *nsock = config->socks[i];
1088
1089 if (!nsock->dead)
1090 continue;
1091
1092 mutex_lock(&nsock->tx_lock);
1093 if (!nsock->dead) {
1094 mutex_unlock(&nsock->tx_lock);
1095 continue;
1096 }
1097 sk_set_memalloc(sock->sk);
1098 if (nbd->tag_set.timeout)
1099 sock->sk->sk_sndtimeo = nbd->tag_set.timeout;
1100 atomic_inc(&config->recv_threads);
1101 refcount_inc(&nbd->config_refs);
1102 old = nsock->sock;
1103 nsock->fallback_index = -1;
1104 nsock->sock = sock;
1105 nsock->dead = false;
1106 INIT_WORK(&args->work, recv_work);
1107 args->index = i;
1108 args->nbd = nbd;
1109 nsock->cookie++;
1110 mutex_unlock(&nsock->tx_lock);
1111 sockfd_put(old);
1112
1113 clear_bit(NBD_RT_DISCONNECTED, &config->runtime_flags);
1114
1115 /* We take the tx_mutex in an error path in the recv_work, so we
1116 * need to queue_work outside of the tx_mutex.
1117 */
1118 queue_work(nbd->recv_workq, &args->work);
1119
1120 atomic_inc(&config->live_connections);
1121 wake_up(&config->conn_wait);
1122 return 0;
1123 }
1124 sockfd_put(sock);
1125 kfree(args);
1126 return -ENOSPC;
1127 }
1128
1129 static void nbd_bdev_reset(struct block_device *bdev)
1130 {
1131 if (bdev->bd_openers > 1)
1132 return;
1133 bd_set_size(bdev, 0);
1134 }
1135
1136 static void nbd_parse_flags(struct nbd_device *nbd)
1137 {
1138 struct nbd_config *config = nbd->config;
1139 if (config->flags & NBD_FLAG_READ_ONLY)
1140 set_disk_ro(nbd->disk, true);
1141 else
1142 set_disk_ro(nbd->disk, false);
1143 if (config->flags & NBD_FLAG_SEND_TRIM)
1144 blk_queue_flag_set(QUEUE_FLAG_DISCARD, nbd->disk->queue);
1145 if (config->flags & NBD_FLAG_SEND_FLUSH) {
1146 if (config->flags & NBD_FLAG_SEND_FUA)
1147 blk_queue_write_cache(nbd->disk->queue, true, true);
1148 else
1149 blk_queue_write_cache(nbd->disk->queue, true, false);
1150 }
1151 else
1152 blk_queue_write_cache(nbd->disk->queue, false, false);
1153 }
1154
1155 static void send_disconnects(struct nbd_device *nbd)
1156 {
1157 struct nbd_config *config = nbd->config;
1158 struct nbd_request request = {
1159 .magic = htonl(NBD_REQUEST_MAGIC),
1160 .type = htonl(NBD_CMD_DISC),
1161 };
1162 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
1163 struct iov_iter from;
1164 int i, ret;
1165
1166 for (i = 0; i < config->num_connections; i++) {
1167 struct nbd_sock *nsock = config->socks[i];
1168
1169 iov_iter_kvec(&from, WRITE, &iov, 1, sizeof(request));
1170 mutex_lock(&nsock->tx_lock);
1171 ret = sock_xmit(nbd, i, 1, &from, 0, NULL);
1172 if (ret <= 0)
1173 dev_err(disk_to_dev(nbd->disk),
1174 "Send disconnect failed %d\n", ret);
1175 mutex_unlock(&nsock->tx_lock);
1176 }
1177 }
1178
1179 static int nbd_disconnect(struct nbd_device *nbd)
1180 {
1181 struct nbd_config *config = nbd->config;
1182
1183 dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
1184 set_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags);
1185 set_bit(NBD_DISCONNECT_REQUESTED, &nbd->flags);
1186 send_disconnects(nbd);
1187 return 0;
1188 }
1189
1190 static void nbd_clear_sock(struct nbd_device *nbd)
1191 {
1192 sock_shutdown(nbd);
1193 nbd_clear_que(nbd);
1194 nbd->task_setup = NULL;
1195 }
1196
1197 static void nbd_config_put(struct nbd_device *nbd)
1198 {
1199 if (refcount_dec_and_mutex_lock(&nbd->config_refs,
1200 &nbd->config_lock)) {
1201 struct nbd_config *config = nbd->config;
1202 nbd_dev_dbg_close(nbd);
1203 nbd_size_clear(nbd);
1204 if (test_and_clear_bit(NBD_RT_HAS_PID_FILE,
1205 &config->runtime_flags))
1206 device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
1207 nbd->task_recv = NULL;
1208 nbd_clear_sock(nbd);
1209 if (config->num_connections) {
1210 int i;
1211 for (i = 0; i < config->num_connections; i++) {
1212 sockfd_put(config->socks[i]->sock);
1213 kfree(config->socks[i]);
1214 }
1215 kfree(config->socks);
1216 }
1217 kfree(nbd->config);
1218 nbd->config = NULL;
1219
1220 if (nbd->recv_workq)
1221 destroy_workqueue(nbd->recv_workq);
1222 nbd->recv_workq = NULL;
1223
1224 nbd->tag_set.timeout = 0;
1225 nbd->disk->queue->limits.discard_granularity = 0;
1226 nbd->disk->queue->limits.discard_alignment = 0;
1227 blk_queue_max_discard_sectors(nbd->disk->queue, UINT_MAX);
1228 blk_queue_flag_clear(QUEUE_FLAG_DISCARD, nbd->disk->queue);
1229
1230 mutex_unlock(&nbd->config_lock);
1231 nbd_put(nbd);
1232 module_put(THIS_MODULE);
1233 }
1234 }
1235
1236 static int nbd_start_device(struct nbd_device *nbd)
1237 {
1238 struct nbd_config *config = nbd->config;
1239 int num_connections = config->num_connections;
1240 int error = 0, i;
1241
1242 if (nbd->task_recv)
1243 return -EBUSY;
1244 if (!config->socks)
1245 return -EINVAL;
1246 if (num_connections > 1 &&
1247 !(config->flags & NBD_FLAG_CAN_MULTI_CONN)) {
1248 dev_err(disk_to_dev(nbd->disk), "server does not support multiple connections per device.\n");
1249 return -EINVAL;
1250 }
1251
1252 nbd->recv_workq = alloc_workqueue("knbd%d-recv",
1253 WQ_MEM_RECLAIM | WQ_HIGHPRI |
1254 WQ_UNBOUND, 0, nbd->index);
1255 if (!nbd->recv_workq) {
1256 dev_err(disk_to_dev(nbd->disk), "Could not allocate knbd recv work queue.\n");
1257 return -ENOMEM;
1258 }
1259
1260 blk_mq_update_nr_hw_queues(&nbd->tag_set, config->num_connections);
1261 nbd->task_recv = current;
1262
1263 nbd_parse_flags(nbd);
1264
1265 error = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
1266 if (error) {
1267 dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n");
1268 return error;
1269 }
1270 set_bit(NBD_RT_HAS_PID_FILE, &config->runtime_flags);
1271
1272 nbd_dev_dbg_init(nbd);
1273 for (i = 0; i < num_connections; i++) {
1274 struct recv_thread_args *args;
1275
1276 args = kzalloc(sizeof(*args), GFP_KERNEL);
1277 if (!args) {
1278 sock_shutdown(nbd);
1279 /*
1280 * If num_connections is m (2 < m),
1281 * and NO.1 ~ NO.n(1 < n < m) kzallocs are successful.
1282 * But NO.(n + 1) failed. We still have n recv threads.
1283 * So, add flush_workqueue here to prevent recv threads
1284 * dropping the last config_refs and trying to destroy
1285 * the workqueue from inside the workqueue.
1286 */
1287 if (i)
1288 flush_workqueue(nbd->recv_workq);
1289 return -ENOMEM;
1290 }
1291 sk_set_memalloc(config->socks[i]->sock->sk);
1292 if (nbd->tag_set.timeout)
1293 config->socks[i]->sock->sk->sk_sndtimeo =
1294 nbd->tag_set.timeout;
1295 atomic_inc(&config->recv_threads);
1296 refcount_inc(&nbd->config_refs);
1297 INIT_WORK(&args->work, recv_work);
1298 args->nbd = nbd;
1299 args->index = i;
1300 queue_work(nbd->recv_workq, &args->work);
1301 }
1302 nbd_size_update(nbd);
1303 return error;
1304 }
1305
1306 static int nbd_start_device_ioctl(struct nbd_device *nbd, struct block_device *bdev)
1307 {
1308 struct nbd_config *config = nbd->config;
1309 int ret;
1310
1311 ret = nbd_start_device(nbd);
1312 if (ret)
1313 return ret;
1314
1315 if (max_part)
1316 bdev->bd_invalidated = 1;
1317 mutex_unlock(&nbd->config_lock);
1318 ret = wait_event_interruptible(config->recv_wq,
1319 atomic_read(&config->recv_threads) == 0);
1320 if (ret)
1321 sock_shutdown(nbd);
1322 flush_workqueue(nbd->recv_workq);
1323
1324 mutex_lock(&nbd->config_lock);
1325 nbd_bdev_reset(bdev);
1326 /* user requested, ignore socket errors */
1327 if (test_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags))
1328 ret = 0;
1329 if (test_bit(NBD_RT_TIMEDOUT, &config->runtime_flags))
1330 ret = -ETIMEDOUT;
1331 return ret;
1332 }
1333
1334 static void nbd_clear_sock_ioctl(struct nbd_device *nbd,
1335 struct block_device *bdev)
1336 {
1337 sock_shutdown(nbd);
1338 __invalidate_device(bdev, true);
1339 nbd_bdev_reset(bdev);
1340 if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF,
1341 &nbd->config->runtime_flags))
1342 nbd_config_put(nbd);
1343 }
1344
1345 static bool nbd_is_valid_blksize(unsigned long blksize)
1346 {
1347 if (!blksize || !is_power_of_2(blksize) || blksize < 512 ||
1348 blksize > PAGE_SIZE)
1349 return false;
1350 return true;
1351 }
1352
1353 static void nbd_set_cmd_timeout(struct nbd_device *nbd, u64 timeout)
1354 {
1355 nbd->tag_set.timeout = timeout * HZ;
1356 if (timeout)
1357 blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ);
1358 }
1359
1360 /* Must be called with config_lock held */
1361 static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
1362 unsigned int cmd, unsigned long arg)
1363 {
1364 struct nbd_config *config = nbd->config;
1365
1366 switch (cmd) {
1367 case NBD_DISCONNECT:
1368 return nbd_disconnect(nbd);
1369 case NBD_CLEAR_SOCK:
1370 nbd_clear_sock_ioctl(nbd, bdev);
1371 return 0;
1372 case NBD_SET_SOCK:
1373 return nbd_add_socket(nbd, arg, false);
1374 case NBD_SET_BLKSIZE:
1375 if (!arg)
1376 arg = NBD_DEF_BLKSIZE;
1377 if (!nbd_is_valid_blksize(arg))
1378 return -EINVAL;
1379 nbd_size_set(nbd, arg,
1380 div_s64(config->bytesize, arg));
1381 return 0;
1382 case NBD_SET_SIZE:
1383 nbd_size_set(nbd, config->blksize,
1384 div_s64(arg, config->blksize));
1385 return 0;
1386 case NBD_SET_SIZE_BLOCKS:
1387 nbd_size_set(nbd, config->blksize, arg);
1388 return 0;
1389 case NBD_SET_TIMEOUT:
1390 nbd_set_cmd_timeout(nbd, arg);
1391 return 0;
1392
1393 case NBD_SET_FLAGS:
1394 config->flags = arg;
1395 return 0;
1396 case NBD_DO_IT:
1397 return nbd_start_device_ioctl(nbd, bdev);
1398 case NBD_CLEAR_QUE:
1399 /*
1400 * This is for compatibility only. The queue is always cleared
1401 * by NBD_DO_IT or NBD_CLEAR_SOCK.
1402 */
1403 return 0;
1404 case NBD_PRINT_DEBUG:
1405 /*
1406 * For compatibility only, we no longer keep a list of
1407 * outstanding requests.
1408 */
1409 return 0;
1410 }
1411 return -ENOTTY;
1412 }
1413
1414 static int nbd_ioctl(struct block_device *bdev, fmode_t mode,
1415 unsigned int cmd, unsigned long arg)
1416 {
1417 struct nbd_device *nbd = bdev->bd_disk->private_data;
1418 struct nbd_config *config = nbd->config;
1419 int error = -EINVAL;
1420
1421 if (!capable(CAP_SYS_ADMIN))
1422 return -EPERM;
1423
1424 /* The block layer will pass back some non-nbd ioctls in case we have
1425 * special handling for them, but we don't so just return an error.
1426 */
1427 if (_IOC_TYPE(cmd) != 0xab)
1428 return -EINVAL;
1429
1430 mutex_lock(&nbd->config_lock);
1431
1432 /* Don't allow ioctl operations on a nbd device that was created with
1433 * netlink, unless it's DISCONNECT or CLEAR_SOCK, which are fine.
1434 */
1435 if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) ||
1436 (cmd == NBD_DISCONNECT || cmd == NBD_CLEAR_SOCK))
1437 error = __nbd_ioctl(bdev, nbd, cmd, arg);
1438 else
1439 dev_err(nbd_to_dev(nbd), "Cannot use ioctl interface on a netlink controlled device.\n");
1440 mutex_unlock(&nbd->config_lock);
1441 return error;
1442 }
1443
1444 static struct nbd_config *nbd_alloc_config(void)
1445 {
1446 struct nbd_config *config;
1447
1448 config = kzalloc(sizeof(struct nbd_config), GFP_NOFS);
1449 if (!config)
1450 return NULL;
1451 atomic_set(&config->recv_threads, 0);
1452 init_waitqueue_head(&config->recv_wq);
1453 init_waitqueue_head(&config->conn_wait);
1454 config->blksize = NBD_DEF_BLKSIZE;
1455 atomic_set(&config->live_connections, 0);
1456 try_module_get(THIS_MODULE);
1457 return config;
1458 }
1459
1460 static int nbd_open(struct block_device *bdev, fmode_t mode)
1461 {
1462 struct nbd_device *nbd;
1463 int ret = 0;
1464
1465 mutex_lock(&nbd_index_mutex);
1466 nbd = bdev->bd_disk->private_data;
1467 if (!nbd) {
1468 ret = -ENXIO;
1469 goto out;
1470 }
1471 if (!refcount_inc_not_zero(&nbd->refs)) {
1472 ret = -ENXIO;
1473 goto out;
1474 }
1475 if (!refcount_inc_not_zero(&nbd->config_refs)) {
1476 struct nbd_config *config;
1477
1478 mutex_lock(&nbd->config_lock);
1479 if (refcount_inc_not_zero(&nbd->config_refs)) {
1480 mutex_unlock(&nbd->config_lock);
1481 goto out;
1482 }
1483 config = nbd->config = nbd_alloc_config();
1484 if (!config) {
1485 ret = -ENOMEM;
1486 mutex_unlock(&nbd->config_lock);
1487 goto out;
1488 }
1489 refcount_set(&nbd->config_refs, 1);
1490 refcount_inc(&nbd->refs);
1491 mutex_unlock(&nbd->config_lock);
1492 bdev->bd_invalidated = 1;
1493 } else if (nbd_disconnected(nbd->config)) {
1494 bdev->bd_invalidated = 1;
1495 }
1496 out:
1497 mutex_unlock(&nbd_index_mutex);
1498 return ret;
1499 }
1500
1501 static void nbd_release(struct gendisk *disk, fmode_t mode)
1502 {
1503 struct nbd_device *nbd = disk->private_data;
1504 struct block_device *bdev = bdget_disk(disk, 0);
1505
1506 if (test_bit(NBD_RT_DISCONNECT_ON_CLOSE, &nbd->config->runtime_flags) &&
1507 bdev->bd_openers == 0)
1508 nbd_disconnect_and_put(nbd);
1509
1510 nbd_config_put(nbd);
1511 nbd_put(nbd);
1512 }
1513
1514 static const struct block_device_operations nbd_fops =
1515 {
1516 .owner = THIS_MODULE,
1517 .open = nbd_open,
1518 .release = nbd_release,
1519 .ioctl = nbd_ioctl,
1520 .compat_ioctl = nbd_ioctl,
1521 };
1522
1523 #if IS_ENABLED(CONFIG_DEBUG_FS)
1524
1525 static int nbd_dbg_tasks_show(struct seq_file *s, void *unused)
1526 {
1527 struct nbd_device *nbd = s->private;
1528
1529 if (nbd->task_recv)
1530 seq_printf(s, "recv: %d\n", task_pid_nr(nbd->task_recv));
1531
1532 return 0;
1533 }
1534
1535 static int nbd_dbg_tasks_open(struct inode *inode, struct file *file)
1536 {
1537 return single_open(file, nbd_dbg_tasks_show, inode->i_private);
1538 }
1539
1540 static const struct file_operations nbd_dbg_tasks_ops = {
1541 .open = nbd_dbg_tasks_open,
1542 .read = seq_read,
1543 .llseek = seq_lseek,
1544 .release = single_release,
1545 };
1546
1547 static int nbd_dbg_flags_show(struct seq_file *s, void *unused)
1548 {
1549 struct nbd_device *nbd = s->private;
1550 u32 flags = nbd->config->flags;
1551
1552 seq_printf(s, "Hex: 0x%08x\n\n", flags);
1553
1554 seq_puts(s, "Known flags:\n");
1555
1556 if (flags & NBD_FLAG_HAS_FLAGS)
1557 seq_puts(s, "NBD_FLAG_HAS_FLAGS\n");
1558 if (flags & NBD_FLAG_READ_ONLY)
1559 seq_puts(s, "NBD_FLAG_READ_ONLY\n");
1560 if (flags & NBD_FLAG_SEND_FLUSH)
1561 seq_puts(s, "NBD_FLAG_SEND_FLUSH\n");
1562 if (flags & NBD_FLAG_SEND_FUA)
1563 seq_puts(s, "NBD_FLAG_SEND_FUA\n");
1564 if (flags & NBD_FLAG_SEND_TRIM)
1565 seq_puts(s, "NBD_FLAG_SEND_TRIM\n");
1566
1567 return 0;
1568 }
1569
1570 static int nbd_dbg_flags_open(struct inode *inode, struct file *file)
1571 {
1572 return single_open(file, nbd_dbg_flags_show, inode->i_private);
1573 }
1574
1575 static const struct file_operations nbd_dbg_flags_ops = {
1576 .open = nbd_dbg_flags_open,
1577 .read = seq_read,
1578 .llseek = seq_lseek,
1579 .release = single_release,
1580 };
1581
1582 static int nbd_dev_dbg_init(struct nbd_device *nbd)
1583 {
1584 struct dentry *dir;
1585 struct nbd_config *config = nbd->config;
1586
1587 if (!nbd_dbg_dir)
1588 return -EIO;
1589
1590 dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir);
1591 if (!dir) {
1592 dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s'\n",
1593 nbd_name(nbd));
1594 return -EIO;
1595 }
1596 config->dbg_dir = dir;
1597
1598 debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_ops);
1599 debugfs_create_u64("size_bytes", 0444, dir, &config->bytesize);
1600 debugfs_create_u32("timeout", 0444, dir, &nbd->tag_set.timeout);
1601 debugfs_create_u64("blocksize", 0444, dir, &config->blksize);
1602 debugfs_create_file("flags", 0444, dir, nbd, &nbd_dbg_flags_ops);
1603
1604 return 0;
1605 }
1606
1607 static void nbd_dev_dbg_close(struct nbd_device *nbd)
1608 {
1609 debugfs_remove_recursive(nbd->config->dbg_dir);
1610 }
1611
1612 static int nbd_dbg_init(void)
1613 {
1614 struct dentry *dbg_dir;
1615
1616 dbg_dir = debugfs_create_dir("nbd", NULL);
1617 if (!dbg_dir)
1618 return -EIO;
1619
1620 nbd_dbg_dir = dbg_dir;
1621
1622 return 0;
1623 }
1624
1625 static void nbd_dbg_close(void)
1626 {
1627 debugfs_remove_recursive(nbd_dbg_dir);
1628 }
1629
1630 #else /* IS_ENABLED(CONFIG_DEBUG_FS) */
1631
1632 static int nbd_dev_dbg_init(struct nbd_device *nbd)
1633 {
1634 return 0;
1635 }
1636
1637 static void nbd_dev_dbg_close(struct nbd_device *nbd)
1638 {
1639 }
1640
1641 static int nbd_dbg_init(void)
1642 {
1643 return 0;
1644 }
1645
1646 static void nbd_dbg_close(void)
1647 {
1648 }
1649
1650 #endif
1651
1652 static int nbd_init_request(struct blk_mq_tag_set *set, struct request *rq,
1653 unsigned int hctx_idx, unsigned int numa_node)
1654 {
1655 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq);
1656 cmd->nbd = set->driver_data;
1657 cmd->flags = 0;
1658 mutex_init(&cmd->lock);
1659 return 0;
1660 }
1661
1662 static const struct blk_mq_ops nbd_mq_ops = {
1663 .queue_rq = nbd_queue_rq,
1664 .complete = nbd_complete_rq,
1665 .init_request = nbd_init_request,
1666 .timeout = nbd_xmit_timeout,
1667 };
1668
1669 static int nbd_dev_add(int index)
1670 {
1671 struct nbd_device *nbd;
1672 struct gendisk *disk;
1673 struct request_queue *q;
1674 int err = -ENOMEM;
1675
1676 nbd = kzalloc(sizeof(struct nbd_device), GFP_KERNEL);
1677 if (!nbd)
1678 goto out;
1679
1680 disk = alloc_disk(1 << part_shift);
1681 if (!disk)
1682 goto out_free_nbd;
1683
1684 if (index >= 0) {
1685 err = idr_alloc(&nbd_index_idr, nbd, index, index + 1,
1686 GFP_KERNEL);
1687 if (err == -ENOSPC)
1688 err = -EEXIST;
1689 } else {
1690 err = idr_alloc(&nbd_index_idr, nbd, 0, 0, GFP_KERNEL);
1691 if (err >= 0)
1692 index = err;
1693 }
1694 if (err < 0)
1695 goto out_free_disk;
1696
1697 nbd->index = index;
1698 nbd->disk = disk;
1699 nbd->tag_set.ops = &nbd_mq_ops;
1700 nbd->tag_set.nr_hw_queues = 1;
1701 nbd->tag_set.queue_depth = 128;
1702 nbd->tag_set.numa_node = NUMA_NO_NODE;
1703 nbd->tag_set.cmd_size = sizeof(struct nbd_cmd);
1704 nbd->tag_set.flags = BLK_MQ_F_SHOULD_MERGE |
1705 BLK_MQ_F_BLOCKING;
1706 nbd->tag_set.driver_data = nbd;
1707 nbd->destroy_complete = NULL;
1708
1709 err = blk_mq_alloc_tag_set(&nbd->tag_set);
1710 if (err)
1711 goto out_free_idr;
1712
1713 q = blk_mq_init_queue(&nbd->tag_set);
1714 if (IS_ERR(q)) {
1715 err = PTR_ERR(q);
1716 goto out_free_tags;
1717 }
1718 disk->queue = q;
1719
1720 /*
1721 * Tell the block layer that we are not a rotational device
1722 */
1723 blk_queue_flag_set(QUEUE_FLAG_NONROT, disk->queue);
1724 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, disk->queue);
1725 disk->queue->limits.discard_granularity = 0;
1726 disk->queue->limits.discard_alignment = 0;
1727 blk_queue_max_discard_sectors(disk->queue, 0);
1728 blk_queue_max_segment_size(disk->queue, UINT_MAX);
1729 blk_queue_max_segments(disk->queue, USHRT_MAX);
1730 blk_queue_max_hw_sectors(disk->queue, 65536);
1731 disk->queue->limits.max_sectors = 256;
1732
1733 mutex_init(&nbd->config_lock);
1734 refcount_set(&nbd->config_refs, 0);
1735 refcount_set(&nbd->refs, 1);
1736 INIT_LIST_HEAD(&nbd->list);
1737 disk->major = NBD_MAJOR;
1738 disk->first_minor = index << part_shift;
1739 disk->fops = &nbd_fops;
1740 disk->private_data = nbd;
1741 sprintf(disk->disk_name, "nbd%d", index);
1742 add_disk(disk);
1743 nbd_total_devices++;
1744 return index;
1745
1746 out_free_tags:
1747 blk_mq_free_tag_set(&nbd->tag_set);
1748 out_free_idr:
1749 idr_remove(&nbd_index_idr, index);
1750 out_free_disk:
1751 put_disk(disk);
1752 out_free_nbd:
1753 kfree(nbd);
1754 out:
1755 return err;
1756 }
1757
1758 static int find_free_cb(int id, void *ptr, void *data)
1759 {
1760 struct nbd_device *nbd = ptr;
1761 struct nbd_device **found = data;
1762
1763 if (!refcount_read(&nbd->config_refs)) {
1764 *found = nbd;
1765 return 1;
1766 }
1767 return 0;
1768 }
1769
1770 /* Netlink interface. */
1771 static const struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = {
1772 [NBD_ATTR_INDEX] = { .type = NLA_U32 },
1773 [NBD_ATTR_SIZE_BYTES] = { .type = NLA_U64 },
1774 [NBD_ATTR_BLOCK_SIZE_BYTES] = { .type = NLA_U64 },
1775 [NBD_ATTR_TIMEOUT] = { .type = NLA_U64 },
1776 [NBD_ATTR_SERVER_FLAGS] = { .type = NLA_U64 },
1777 [NBD_ATTR_CLIENT_FLAGS] = { .type = NLA_U64 },
1778 [NBD_ATTR_SOCKETS] = { .type = NLA_NESTED},
1779 [NBD_ATTR_DEAD_CONN_TIMEOUT] = { .type = NLA_U64 },
1780 [NBD_ATTR_DEVICE_LIST] = { .type = NLA_NESTED},
1781 };
1782
1783 static const struct nla_policy nbd_sock_policy[NBD_SOCK_MAX + 1] = {
1784 [NBD_SOCK_FD] = { .type = NLA_U32 },
1785 };
1786
1787 /* We don't use this right now since we don't parse the incoming list, but we
1788 * still want it here so userspace knows what to expect.
1789 */
1790 static const struct nla_policy __attribute__((unused))
1791 nbd_device_policy[NBD_DEVICE_ATTR_MAX + 1] = {
1792 [NBD_DEVICE_INDEX] = { .type = NLA_U32 },
1793 [NBD_DEVICE_CONNECTED] = { .type = NLA_U8 },
1794 };
1795
1796 static int nbd_genl_size_set(struct genl_info *info, struct nbd_device *nbd)
1797 {
1798 struct nbd_config *config = nbd->config;
1799 u64 bsize = config->blksize;
1800 u64 bytes = config->bytesize;
1801
1802 if (info->attrs[NBD_ATTR_SIZE_BYTES])
1803 bytes = nla_get_u64(info->attrs[NBD_ATTR_SIZE_BYTES]);
1804
1805 if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]) {
1806 bsize = nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]);
1807 if (!bsize)
1808 bsize = NBD_DEF_BLKSIZE;
1809 if (!nbd_is_valid_blksize(bsize)) {
1810 printk(KERN_ERR "Invalid block size %llu\n", bsize);
1811 return -EINVAL;
1812 }
1813 }
1814
1815 if (bytes != config->bytesize || bsize != config->blksize)
1816 nbd_size_set(nbd, bsize, div64_u64(bytes, bsize));
1817 return 0;
1818 }
1819
1820 static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
1821 {
1822 DECLARE_COMPLETION_ONSTACK(destroy_complete);
1823 struct nbd_device *nbd = NULL;
1824 struct nbd_config *config;
1825 int index = -1;
1826 int ret;
1827 bool put_dev = false;
1828
1829 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1830 return -EPERM;
1831
1832 if (info->attrs[NBD_ATTR_INDEX])
1833 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1834 if (!info->attrs[NBD_ATTR_SOCKETS]) {
1835 printk(KERN_ERR "nbd: must specify at least one socket\n");
1836 return -EINVAL;
1837 }
1838 if (!info->attrs[NBD_ATTR_SIZE_BYTES]) {
1839 printk(KERN_ERR "nbd: must specify a size in bytes for the device\n");
1840 return -EINVAL;
1841 }
1842 again:
1843 mutex_lock(&nbd_index_mutex);
1844 if (index == -1) {
1845 ret = idr_for_each(&nbd_index_idr, &find_free_cb, &nbd);
1846 if (ret == 0) {
1847 int new_index;
1848 new_index = nbd_dev_add(-1);
1849 if (new_index < 0) {
1850 mutex_unlock(&nbd_index_mutex);
1851 printk(KERN_ERR "nbd: failed to add new device\n");
1852 return new_index;
1853 }
1854 nbd = idr_find(&nbd_index_idr, new_index);
1855 }
1856 } else {
1857 nbd = idr_find(&nbd_index_idr, index);
1858 if (!nbd) {
1859 ret = nbd_dev_add(index);
1860 if (ret < 0) {
1861 mutex_unlock(&nbd_index_mutex);
1862 printk(KERN_ERR "nbd: failed to add new device\n");
1863 return ret;
1864 }
1865 nbd = idr_find(&nbd_index_idr, index);
1866 }
1867 }
1868 if (!nbd) {
1869 printk(KERN_ERR "nbd: couldn't find device at index %d\n",
1870 index);
1871 mutex_unlock(&nbd_index_mutex);
1872 return -EINVAL;
1873 }
1874
1875 if (test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags) &&
1876 test_bit(NBD_DISCONNECT_REQUESTED, &nbd->flags)) {
1877 nbd->destroy_complete = &destroy_complete;
1878 mutex_unlock(&nbd_index_mutex);
1879
1880 /* Wait untill the the nbd stuff is totally destroyed */
1881 wait_for_completion(&destroy_complete);
1882 goto again;
1883 }
1884
1885 if (!refcount_inc_not_zero(&nbd->refs)) {
1886 mutex_unlock(&nbd_index_mutex);
1887 if (index == -1)
1888 goto again;
1889 printk(KERN_ERR "nbd: device at index %d is going down\n",
1890 index);
1891 return -EINVAL;
1892 }
1893 mutex_unlock(&nbd_index_mutex);
1894
1895 mutex_lock(&nbd->config_lock);
1896 if (refcount_read(&nbd->config_refs)) {
1897 mutex_unlock(&nbd->config_lock);
1898 nbd_put(nbd);
1899 if (index == -1)
1900 goto again;
1901 printk(KERN_ERR "nbd: nbd%d already in use\n", index);
1902 return -EBUSY;
1903 }
1904 if (WARN_ON(nbd->config)) {
1905 mutex_unlock(&nbd->config_lock);
1906 nbd_put(nbd);
1907 return -EINVAL;
1908 }
1909 config = nbd->config = nbd_alloc_config();
1910 if (!nbd->config) {
1911 mutex_unlock(&nbd->config_lock);
1912 nbd_put(nbd);
1913 printk(KERN_ERR "nbd: couldn't allocate config\n");
1914 return -ENOMEM;
1915 }
1916 refcount_set(&nbd->config_refs, 1);
1917 set_bit(NBD_RT_BOUND, &config->runtime_flags);
1918
1919 ret = nbd_genl_size_set(info, nbd);
1920 if (ret)
1921 goto out;
1922
1923 if (info->attrs[NBD_ATTR_TIMEOUT])
1924 nbd_set_cmd_timeout(nbd,
1925 nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]));
1926 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
1927 config->dead_conn_timeout =
1928 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
1929 config->dead_conn_timeout *= HZ;
1930 }
1931 if (info->attrs[NBD_ATTR_SERVER_FLAGS])
1932 config->flags =
1933 nla_get_u64(info->attrs[NBD_ATTR_SERVER_FLAGS]);
1934 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
1935 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
1936 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
1937 set_bit(NBD_RT_DESTROY_ON_DISCONNECT,
1938 &config->runtime_flags);
1939 set_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags);
1940 put_dev = true;
1941 } else {
1942 clear_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags);
1943 }
1944 if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {
1945 set_bit(NBD_RT_DISCONNECT_ON_CLOSE,
1946 &config->runtime_flags);
1947 }
1948 }
1949
1950 if (info->attrs[NBD_ATTR_SOCKETS]) {
1951 struct nlattr *attr;
1952 int rem, fd;
1953
1954 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
1955 rem) {
1956 struct nlattr *socks[NBD_SOCK_MAX+1];
1957
1958 if (nla_type(attr) != NBD_SOCK_ITEM) {
1959 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");
1960 ret = -EINVAL;
1961 goto out;
1962 }
1963 ret = nla_parse_nested_deprecated(socks, NBD_SOCK_MAX,
1964 attr,
1965 nbd_sock_policy,
1966 info->extack);
1967 if (ret != 0) {
1968 printk(KERN_ERR "nbd: error processing sock list\n");
1969 ret = -EINVAL;
1970 goto out;
1971 }
1972 if (!socks[NBD_SOCK_FD])
1973 continue;
1974 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
1975 ret = nbd_add_socket(nbd, fd, true);
1976 if (ret)
1977 goto out;
1978 }
1979 }
1980 ret = nbd_start_device(nbd);
1981 out:
1982 mutex_unlock(&nbd->config_lock);
1983 if (!ret) {
1984 set_bit(NBD_RT_HAS_CONFIG_REF, &config->runtime_flags);
1985 refcount_inc(&nbd->config_refs);
1986 nbd_connect_reply(info, nbd->index);
1987 }
1988 nbd_config_put(nbd);
1989 if (put_dev)
1990 nbd_put(nbd);
1991 return ret;
1992 }
1993
1994 static void nbd_disconnect_and_put(struct nbd_device *nbd)
1995 {
1996 mutex_lock(&nbd->config_lock);
1997 nbd_disconnect(nbd);
1998 nbd_clear_sock(nbd);
1999 mutex_unlock(&nbd->config_lock);
2000 /*
2001 * Make sure recv thread has finished, so it does not drop the last
2002 * config ref and try to destroy the workqueue from inside the work
2003 * queue.
2004 */
2005 flush_workqueue(nbd->recv_workq);
2006 if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF,
2007 &nbd->config->runtime_flags))
2008 nbd_config_put(nbd);
2009 }
2010
2011 static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info)
2012 {
2013 struct nbd_device *nbd;
2014 int index;
2015
2016 if (!netlink_capable(skb, CAP_SYS_ADMIN))
2017 return -EPERM;
2018
2019 if (!info->attrs[NBD_ATTR_INDEX]) {
2020 printk(KERN_ERR "nbd: must specify an index to disconnect\n");
2021 return -EINVAL;
2022 }
2023 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2024 mutex_lock(&nbd_index_mutex);
2025 nbd = idr_find(&nbd_index_idr, index);
2026 if (!nbd) {
2027 mutex_unlock(&nbd_index_mutex);
2028 printk(KERN_ERR "nbd: couldn't find device at index %d\n",
2029 index);
2030 return -EINVAL;
2031 }
2032 if (!refcount_inc_not_zero(&nbd->refs)) {
2033 mutex_unlock(&nbd_index_mutex);
2034 printk(KERN_ERR "nbd: device at index %d is going down\n",
2035 index);
2036 return -EINVAL;
2037 }
2038 mutex_unlock(&nbd_index_mutex);
2039 if (!refcount_inc_not_zero(&nbd->config_refs)) {
2040 nbd_put(nbd);
2041 return 0;
2042 }
2043 nbd_disconnect_and_put(nbd);
2044 nbd_config_put(nbd);
2045 nbd_put(nbd);
2046 return 0;
2047 }
2048
2049 static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info)
2050 {
2051 struct nbd_device *nbd = NULL;
2052 struct nbd_config *config;
2053 int index;
2054 int ret = 0;
2055 bool put_dev = false;
2056
2057 if (!netlink_capable(skb, CAP_SYS_ADMIN))
2058 return -EPERM;
2059
2060 if (!info->attrs[NBD_ATTR_INDEX]) {
2061 printk(KERN_ERR "nbd: must specify a device to reconfigure\n");
2062 return -EINVAL;
2063 }
2064 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2065 mutex_lock(&nbd_index_mutex);
2066 nbd = idr_find(&nbd_index_idr, index);
2067 if (!nbd) {
2068 mutex_unlock(&nbd_index_mutex);
2069 printk(KERN_ERR "nbd: couldn't find a device at index %d\n",
2070 index);
2071 return -EINVAL;
2072 }
2073 if (!refcount_inc_not_zero(&nbd->refs)) {
2074 mutex_unlock(&nbd_index_mutex);
2075 printk(KERN_ERR "nbd: device at index %d is going down\n",
2076 index);
2077 return -EINVAL;
2078 }
2079 mutex_unlock(&nbd_index_mutex);
2080
2081 if (!refcount_inc_not_zero(&nbd->config_refs)) {
2082 dev_err(nbd_to_dev(nbd),
2083 "not configured, cannot reconfigure\n");
2084 nbd_put(nbd);
2085 return -EINVAL;
2086 }
2087
2088 mutex_lock(&nbd->config_lock);
2089 config = nbd->config;
2090 if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) ||
2091 !nbd->task_recv) {
2092 dev_err(nbd_to_dev(nbd),
2093 "not configured, cannot reconfigure\n");
2094 ret = -EINVAL;
2095 goto out;
2096 }
2097
2098 ret = nbd_genl_size_set(info, nbd);
2099 if (ret)
2100 goto out;
2101
2102 if (info->attrs[NBD_ATTR_TIMEOUT])
2103 nbd_set_cmd_timeout(nbd,
2104 nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]));
2105 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
2106 config->dead_conn_timeout =
2107 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
2108 config->dead_conn_timeout *= HZ;
2109 }
2110 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
2111 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
2112 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
2113 if (!test_and_set_bit(NBD_RT_DESTROY_ON_DISCONNECT,
2114 &config->runtime_flags))
2115 put_dev = true;
2116 set_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags);
2117 } else {
2118 if (test_and_clear_bit(NBD_RT_DESTROY_ON_DISCONNECT,
2119 &config->runtime_flags))
2120 refcount_inc(&nbd->refs);
2121 clear_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags);
2122 }
2123
2124 if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {
2125 set_bit(NBD_RT_DISCONNECT_ON_CLOSE,
2126 &config->runtime_flags);
2127 } else {
2128 clear_bit(NBD_RT_DISCONNECT_ON_CLOSE,
2129 &config->runtime_flags);
2130 }
2131 }
2132
2133 if (info->attrs[NBD_ATTR_SOCKETS]) {
2134 struct nlattr *attr;
2135 int rem, fd;
2136
2137 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
2138 rem) {
2139 struct nlattr *socks[NBD_SOCK_MAX+1];
2140
2141 if (nla_type(attr) != NBD_SOCK_ITEM) {
2142 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");
2143 ret = -EINVAL;
2144 goto out;
2145 }
2146 ret = nla_parse_nested_deprecated(socks, NBD_SOCK_MAX,
2147 attr,
2148 nbd_sock_policy,
2149 info->extack);
2150 if (ret != 0) {
2151 printk(KERN_ERR "nbd: error processing sock list\n");
2152 ret = -EINVAL;
2153 goto out;
2154 }
2155 if (!socks[NBD_SOCK_FD])
2156 continue;
2157 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
2158 ret = nbd_reconnect_socket(nbd, fd);
2159 if (ret) {
2160 if (ret == -ENOSPC)
2161 ret = 0;
2162 goto out;
2163 }
2164 dev_info(nbd_to_dev(nbd), "reconnected socket\n");
2165 }
2166 }
2167 out:
2168 mutex_unlock(&nbd->config_lock);
2169 nbd_config_put(nbd);
2170 nbd_put(nbd);
2171 if (put_dev)
2172 nbd_put(nbd);
2173 return ret;
2174 }
2175
2176 static const struct genl_ops nbd_connect_genl_ops[] = {
2177 {
2178 .cmd = NBD_CMD_CONNECT,
2179 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2180 .doit = nbd_genl_connect,
2181 },
2182 {
2183 .cmd = NBD_CMD_DISCONNECT,
2184 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2185 .doit = nbd_genl_disconnect,
2186 },
2187 {
2188 .cmd = NBD_CMD_RECONFIGURE,
2189 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2190 .doit = nbd_genl_reconfigure,
2191 },
2192 {
2193 .cmd = NBD_CMD_STATUS,
2194 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2195 .doit = nbd_genl_status,
2196 },
2197 };
2198
2199 static const struct genl_multicast_group nbd_mcast_grps[] = {
2200 { .name = NBD_GENL_MCAST_GROUP_NAME, },
2201 };
2202
2203 static struct genl_family nbd_genl_family __ro_after_init = {
2204 .hdrsize = 0,
2205 .name = NBD_GENL_FAMILY_NAME,
2206 .version = NBD_GENL_VERSION,
2207 .module = THIS_MODULE,
2208 .ops = nbd_connect_genl_ops,
2209 .n_ops = ARRAY_SIZE(nbd_connect_genl_ops),
2210 .maxattr = NBD_ATTR_MAX,
2211 .policy = nbd_attr_policy,
2212 .mcgrps = nbd_mcast_grps,
2213 .n_mcgrps = ARRAY_SIZE(nbd_mcast_grps),
2214 };
2215
2216 static int populate_nbd_status(struct nbd_device *nbd, struct sk_buff *reply)
2217 {
2218 struct nlattr *dev_opt;
2219 u8 connected = 0;
2220 int ret;
2221
2222 /* This is a little racey, but for status it's ok. The
2223 * reason we don't take a ref here is because we can't
2224 * take a ref in the index == -1 case as we would need
2225 * to put under the nbd_index_mutex, which could
2226 * deadlock if we are configured to remove ourselves
2227 * once we're disconnected.
2228 */
2229 if (refcount_read(&nbd->config_refs))
2230 connected = 1;
2231 dev_opt = nla_nest_start_noflag(reply, NBD_DEVICE_ITEM);
2232 if (!dev_opt)
2233 return -EMSGSIZE;
2234 ret = nla_put_u32(reply, NBD_DEVICE_INDEX, nbd->index);
2235 if (ret)
2236 return -EMSGSIZE;
2237 ret = nla_put_u8(reply, NBD_DEVICE_CONNECTED,
2238 connected);
2239 if (ret)
2240 return -EMSGSIZE;
2241 nla_nest_end(reply, dev_opt);
2242 return 0;
2243 }
2244
2245 static int status_cb(int id, void *ptr, void *data)
2246 {
2247 struct nbd_device *nbd = ptr;
2248 return populate_nbd_status(nbd, (struct sk_buff *)data);
2249 }
2250
2251 static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info)
2252 {
2253 struct nlattr *dev_list;
2254 struct sk_buff *reply;
2255 void *reply_head;
2256 size_t msg_size;
2257 int index = -1;
2258 int ret = -ENOMEM;
2259
2260 if (info->attrs[NBD_ATTR_INDEX])
2261 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2262
2263 mutex_lock(&nbd_index_mutex);
2264
2265 msg_size = nla_total_size(nla_attr_size(sizeof(u32)) +
2266 nla_attr_size(sizeof(u8)));
2267 msg_size *= (index == -1) ? nbd_total_devices : 1;
2268
2269 reply = genlmsg_new(msg_size, GFP_KERNEL);
2270 if (!reply)
2271 goto out;
2272 reply_head = genlmsg_put_reply(reply, info, &nbd_genl_family, 0,
2273 NBD_CMD_STATUS);
2274 if (!reply_head) {
2275 nlmsg_free(reply);
2276 goto out;
2277 }
2278
2279 dev_list = nla_nest_start_noflag(reply, NBD_ATTR_DEVICE_LIST);
2280 if (index == -1) {
2281 ret = idr_for_each(&nbd_index_idr, &status_cb, reply);
2282 if (ret) {
2283 nlmsg_free(reply);
2284 goto out;
2285 }
2286 } else {
2287 struct nbd_device *nbd;
2288 nbd = idr_find(&nbd_index_idr, index);
2289 if (nbd) {
2290 ret = populate_nbd_status(nbd, reply);
2291 if (ret) {
2292 nlmsg_free(reply);
2293 goto out;
2294 }
2295 }
2296 }
2297 nla_nest_end(reply, dev_list);
2298 genlmsg_end(reply, reply_head);
2299 ret = genlmsg_reply(reply, info);
2300 out:
2301 mutex_unlock(&nbd_index_mutex);
2302 return ret;
2303 }
2304
2305 static void nbd_connect_reply(struct genl_info *info, int index)
2306 {
2307 struct sk_buff *skb;
2308 void *msg_head;
2309 int ret;
2310
2311 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2312 if (!skb)
2313 return;
2314 msg_head = genlmsg_put_reply(skb, info, &nbd_genl_family, 0,
2315 NBD_CMD_CONNECT);
2316 if (!msg_head) {
2317 nlmsg_free(skb);
2318 return;
2319 }
2320 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2321 if (ret) {
2322 nlmsg_free(skb);
2323 return;
2324 }
2325 genlmsg_end(skb, msg_head);
2326 genlmsg_reply(skb, info);
2327 }
2328
2329 static void nbd_mcast_index(int index)
2330 {
2331 struct sk_buff *skb;
2332 void *msg_head;
2333 int ret;
2334
2335 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2336 if (!skb)
2337 return;
2338 msg_head = genlmsg_put(skb, 0, 0, &nbd_genl_family, 0,
2339 NBD_CMD_LINK_DEAD);
2340 if (!msg_head) {
2341 nlmsg_free(skb);
2342 return;
2343 }
2344 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2345 if (ret) {
2346 nlmsg_free(skb);
2347 return;
2348 }
2349 genlmsg_end(skb, msg_head);
2350 genlmsg_multicast(&nbd_genl_family, skb, 0, 0, GFP_KERNEL);
2351 }
2352
2353 static void nbd_dead_link_work(struct work_struct *work)
2354 {
2355 struct link_dead_args *args = container_of(work, struct link_dead_args,
2356 work);
2357 nbd_mcast_index(args->index);
2358 kfree(args);
2359 }
2360
2361 static int __init nbd_init(void)
2362 {
2363 int i;
2364
2365 BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
2366
2367 if (max_part < 0) {
2368 printk(KERN_ERR "nbd: max_part must be >= 0\n");
2369 return -EINVAL;
2370 }
2371
2372 part_shift = 0;
2373 if (max_part > 0) {
2374 part_shift = fls(max_part);
2375
2376 /*
2377 * Adjust max_part according to part_shift as it is exported
2378 * to user space so that user can know the max number of
2379 * partition kernel should be able to manage.
2380 *
2381 * Note that -1 is required because partition 0 is reserved
2382 * for the whole disk.
2383 */
2384 max_part = (1UL << part_shift) - 1;
2385 }
2386
2387 if ((1UL << part_shift) > DISK_MAX_PARTS)
2388 return -EINVAL;
2389
2390 if (nbds_max > 1UL << (MINORBITS - part_shift))
2391 return -EINVAL;
2392
2393 if (register_blkdev(NBD_MAJOR, "nbd"))
2394 return -EIO;
2395
2396 if (genl_register_family(&nbd_genl_family)) {
2397 unregister_blkdev(NBD_MAJOR, "nbd");
2398 return -EINVAL;
2399 }
2400 nbd_dbg_init();
2401
2402 mutex_lock(&nbd_index_mutex);
2403 for (i = 0; i < nbds_max; i++)
2404 nbd_dev_add(i);
2405 mutex_unlock(&nbd_index_mutex);
2406 return 0;
2407 }
2408
2409 static int nbd_exit_cb(int id, void *ptr, void *data)
2410 {
2411 struct list_head *list = (struct list_head *)data;
2412 struct nbd_device *nbd = ptr;
2413
2414 list_add_tail(&nbd->list, list);
2415 return 0;
2416 }
2417
2418 static void __exit nbd_cleanup(void)
2419 {
2420 struct nbd_device *nbd;
2421 LIST_HEAD(del_list);
2422
2423 nbd_dbg_close();
2424
2425 mutex_lock(&nbd_index_mutex);
2426 idr_for_each(&nbd_index_idr, &nbd_exit_cb, &del_list);
2427 mutex_unlock(&nbd_index_mutex);
2428
2429 while (!list_empty(&del_list)) {
2430 nbd = list_first_entry(&del_list, struct nbd_device, list);
2431 list_del_init(&nbd->list);
2432 if (refcount_read(&nbd->refs) != 1)
2433 printk(KERN_ERR "nbd: possibly leaking a device\n");
2434 nbd_put(nbd);
2435 }
2436
2437 idr_destroy(&nbd_index_idr);
2438 genl_unregister_family(&nbd_genl_family);
2439 unregister_blkdev(NBD_MAJOR, "nbd");
2440 }
2441
2442 module_init(nbd_init);
2443 module_exit(nbd_cleanup);
2444
2445 MODULE_DESCRIPTION("Network Block Device");
2446 MODULE_LICENSE("GPL");
2447
2448 module_param(nbds_max, int, 0444);
2449 MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
2450 module_param(max_part, int, 0444);
2451 MODULE_PARM_DESC(max_part, "number of partitions per device (default: 16)");
Linux with added FPC-III support