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 struct workqueue_struct *nbd_del_wq;
53 static int nbd_total_devices = 0;
54
55 struct nbd_sock {
56 struct socket *sock;
57 struct mutex tx_lock;
58 struct request *pending;
59 int sent;
60 bool dead;
61 int fallback_index;
62 int cookie;
63 };
64
65 struct recv_thread_args {
66 struct work_struct work;
67 struct nbd_device *nbd;
68 int index;
69 };
70
71 struct link_dead_args {
72 struct work_struct work;
73 int index;
74 };
75
76 #define NBD_RT_TIMEDOUT 0
77 #define NBD_RT_DISCONNECT_REQUESTED 1
78 #define NBD_RT_DISCONNECTED 2
79 #define NBD_RT_HAS_PID_FILE 3
80 #define NBD_RT_HAS_CONFIG_REF 4
81 #define NBD_RT_BOUND 5
82 #define NBD_RT_DISCONNECT_ON_CLOSE 6
83 #define NBD_RT_HAS_BACKEND_FILE 7
84
85 #define NBD_DESTROY_ON_DISCONNECT 0
86 #define NBD_DISCONNECT_REQUESTED 1
87
88 struct nbd_config {
89 u32 flags;
90 unsigned long runtime_flags;
91 u64 dead_conn_timeout;
92
93 struct nbd_sock **socks;
94 int num_connections;
95 atomic_t live_connections;
96 wait_queue_head_t conn_wait;
97
98 atomic_t recv_threads;
99 wait_queue_head_t recv_wq;
100 unsigned int blksize_bits;
101 loff_t bytesize;
102 #if IS_ENABLED(CONFIG_DEBUG_FS)
103 struct dentry *dbg_dir;
104 #endif
105 };
106
nbd_blksize(struct nbd_config * config)107 static inline unsigned int nbd_blksize(struct nbd_config *config)
108 {
109 return 1u << config->blksize_bits;
110 }
111
112 struct nbd_device {
113 struct blk_mq_tag_set tag_set;
114
115 int index;
116 refcount_t config_refs;
117 refcount_t refs;
118 struct nbd_config *config;
119 struct mutex config_lock;
120 struct gendisk *disk;
121 struct workqueue_struct *recv_workq;
122 struct work_struct remove_work;
123
124 struct list_head list;
125 struct task_struct *task_setup;
126
127 unsigned long flags;
128 pid_t pid; /* pid of nbd-client, if attached */
129
130 char *backend;
131 };
132
133 #define NBD_CMD_REQUEUED 1
134
135 struct nbd_cmd {
136 struct nbd_device *nbd;
137 struct mutex lock;
138 int index;
139 int cookie;
140 int retries;
141 blk_status_t status;
142 unsigned long flags;
143 u32 cmd_cookie;
144 };
145
146 #if IS_ENABLED(CONFIG_DEBUG_FS)
147 static struct dentry *nbd_dbg_dir;
148 #endif
149
150 #define nbd_name(nbd) ((nbd)->disk->disk_name)
151
152 #define NBD_MAGIC 0x68797548
153
154 #define NBD_DEF_BLKSIZE_BITS 10
155
156 static unsigned int nbds_max = 16;
157 static int max_part = 16;
158 static int part_shift;
159
160 static int nbd_dev_dbg_init(struct nbd_device *nbd);
161 static void nbd_dev_dbg_close(struct nbd_device *nbd);
162 static void nbd_config_put(struct nbd_device *nbd);
163 static void nbd_connect_reply(struct genl_info *info, int index);
164 static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info);
165 static void nbd_dead_link_work(struct work_struct *work);
166 static void nbd_disconnect_and_put(struct nbd_device *nbd);
167
nbd_to_dev(struct nbd_device * nbd)168 static inline struct device *nbd_to_dev(struct nbd_device *nbd)
169 {
170 return disk_to_dev(nbd->disk);
171 }
172
nbd_requeue_cmd(struct nbd_cmd * cmd)173 static void nbd_requeue_cmd(struct nbd_cmd *cmd)
174 {
175 struct request *req = blk_mq_rq_from_pdu(cmd);
176
177 if (!test_and_set_bit(NBD_CMD_REQUEUED, &cmd->flags))
178 blk_mq_requeue_request(req, true);
179 }
180
181 #define NBD_COOKIE_BITS 32
182
nbd_cmd_handle(struct nbd_cmd * cmd)183 static u64 nbd_cmd_handle(struct nbd_cmd *cmd)
184 {
185 struct request *req = blk_mq_rq_from_pdu(cmd);
186 u32 tag = blk_mq_unique_tag(req);
187 u64 cookie = cmd->cmd_cookie;
188
189 return (cookie << NBD_COOKIE_BITS) | tag;
190 }
191
nbd_handle_to_tag(u64 handle)192 static u32 nbd_handle_to_tag(u64 handle)
193 {
194 return (u32)handle;
195 }
196
nbd_handle_to_cookie(u64 handle)197 static u32 nbd_handle_to_cookie(u64 handle)
198 {
199 return (u32)(handle >> NBD_COOKIE_BITS);
200 }
201
nbdcmd_to_ascii(int cmd)202 static const char *nbdcmd_to_ascii(int cmd)
203 {
204 switch (cmd) {
205 case NBD_CMD_READ: return "read";
206 case NBD_CMD_WRITE: return "write";
207 case NBD_CMD_DISC: return "disconnect";
208 case NBD_CMD_FLUSH: return "flush";
209 case NBD_CMD_TRIM: return "trim/discard";
210 }
211 return "invalid";
212 }
213
pid_show(struct device * dev,struct device_attribute * attr,char * buf)214 static ssize_t pid_show(struct device *dev,
215 struct device_attribute *attr, char *buf)
216 {
217 struct gendisk *disk = dev_to_disk(dev);
218 struct nbd_device *nbd = (struct nbd_device *)disk->private_data;
219
220 return sprintf(buf, "%d\n", nbd->pid);
221 }
222
223 static const struct device_attribute pid_attr = {
224 .attr = { .name = "pid", .mode = 0444},
225 .show = pid_show,
226 };
227
backend_show(struct device * dev,struct device_attribute * attr,char * buf)228 static ssize_t backend_show(struct device *dev,
229 struct device_attribute *attr, char *buf)
230 {
231 struct gendisk *disk = dev_to_disk(dev);
232 struct nbd_device *nbd = (struct nbd_device *)disk->private_data;
233
234 return sprintf(buf, "%s\n", nbd->backend ?: "");
235 }
236
237 static const struct device_attribute backend_attr = {
238 .attr = { .name = "backend", .mode = 0444},
239 .show = backend_show,
240 };
241
nbd_dev_remove(struct nbd_device * nbd)242 static void nbd_dev_remove(struct nbd_device *nbd)
243 {
244 struct gendisk *disk = nbd->disk;
245
246 del_gendisk(disk);
247 blk_cleanup_disk(disk);
248 blk_mq_free_tag_set(&nbd->tag_set);
249
250 /*
251 * Remove from idr after del_gendisk() completes, so if the same ID is
252 * reused, the following add_disk() will succeed.
253 */
254 mutex_lock(&nbd_index_mutex);
255 idr_remove(&nbd_index_idr, nbd->index);
256 mutex_unlock(&nbd_index_mutex);
257 destroy_workqueue(nbd->recv_workq);
258 kfree(nbd);
259 }
260
nbd_dev_remove_work(struct work_struct * work)261 static void nbd_dev_remove_work(struct work_struct *work)
262 {
263 nbd_dev_remove(container_of(work, struct nbd_device, remove_work));
264 }
265
nbd_put(struct nbd_device * nbd)266 static void nbd_put(struct nbd_device *nbd)
267 {
268 if (!refcount_dec_and_test(&nbd->refs))
269 return;
270
271 /* Call del_gendisk() asynchrounously to prevent deadlock */
272 if (test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags))
273 queue_work(nbd_del_wq, &nbd->remove_work);
274 else
275 nbd_dev_remove(nbd);
276 }
277
nbd_disconnected(struct nbd_config * config)278 static int nbd_disconnected(struct nbd_config *config)
279 {
280 return test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags) ||
281 test_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags);
282 }
283
nbd_mark_nsock_dead(struct nbd_device * nbd,struct nbd_sock * nsock,int notify)284 static void nbd_mark_nsock_dead(struct nbd_device *nbd, struct nbd_sock *nsock,
285 int notify)
286 {
287 if (!nsock->dead && notify && !nbd_disconnected(nbd->config)) {
288 struct link_dead_args *args;
289 args = kmalloc(sizeof(struct link_dead_args), GFP_NOIO);
290 if (args) {
291 INIT_WORK(&args->work, nbd_dead_link_work);
292 args->index = nbd->index;
293 queue_work(system_wq, &args->work);
294 }
295 }
296 if (!nsock->dead) {
297 kernel_sock_shutdown(nsock->sock, SHUT_RDWR);
298 if (atomic_dec_return(&nbd->config->live_connections) == 0) {
299 if (test_and_clear_bit(NBD_RT_DISCONNECT_REQUESTED,
300 &nbd->config->runtime_flags)) {
301 set_bit(NBD_RT_DISCONNECTED,
302 &nbd->config->runtime_flags);
303 dev_info(nbd_to_dev(nbd),
304 "Disconnected due to user request.\n");
305 }
306 }
307 }
308 nsock->dead = true;
309 nsock->pending = NULL;
310 nsock->sent = 0;
311 }
312
nbd_size_clear(struct nbd_device * nbd)313 static void nbd_size_clear(struct nbd_device *nbd)
314 {
315 if (nbd->config->bytesize) {
316 set_capacity(nbd->disk, 0);
317 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
318 }
319 }
320
nbd_set_size(struct nbd_device * nbd,loff_t bytesize,loff_t blksize)321 static int nbd_set_size(struct nbd_device *nbd, loff_t bytesize,
322 loff_t blksize)
323 {
324 if (!blksize)
325 blksize = 1u << NBD_DEF_BLKSIZE_BITS;
326 if (blksize < 512 || blksize > PAGE_SIZE || !is_power_of_2(blksize))
327 return -EINVAL;
328
329 if (bytesize < 0)
330 return -EINVAL;
331
332 nbd->config->bytesize = bytesize;
333 nbd->config->blksize_bits = __ffs(blksize);
334
335 if (!nbd->pid)
336 return 0;
337
338 if (nbd->config->flags & NBD_FLAG_SEND_TRIM) {
339 nbd->disk->queue->limits.discard_granularity = blksize;
340 nbd->disk->queue->limits.discard_alignment = blksize;
341 blk_queue_max_discard_sectors(nbd->disk->queue, UINT_MAX);
342 }
343 blk_queue_logical_block_size(nbd->disk->queue, blksize);
344 blk_queue_physical_block_size(nbd->disk->queue, blksize);
345
346 if (max_part)
347 set_bit(GD_NEED_PART_SCAN, &nbd->disk->state);
348 if (!set_capacity_and_notify(nbd->disk, bytesize >> 9))
349 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
350 return 0;
351 }
352
nbd_complete_rq(struct request * req)353 static void nbd_complete_rq(struct request *req)
354 {
355 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
356
357 dev_dbg(nbd_to_dev(cmd->nbd), "request %p: %s\n", req,
358 cmd->status ? "failed" : "done");
359
360 blk_mq_end_request(req, cmd->status);
361 }
362
363 /*
364 * Forcibly shutdown the socket causing all listeners to error
365 */
sock_shutdown(struct nbd_device * nbd)366 static void sock_shutdown(struct nbd_device *nbd)
367 {
368 struct nbd_config *config = nbd->config;
369 int i;
370
371 if (config->num_connections == 0)
372 return;
373 if (test_and_set_bit(NBD_RT_DISCONNECTED, &config->runtime_flags))
374 return;
375
376 for (i = 0; i < config->num_connections; i++) {
377 struct nbd_sock *nsock = config->socks[i];
378 mutex_lock(&nsock->tx_lock);
379 nbd_mark_nsock_dead(nbd, nsock, 0);
380 mutex_unlock(&nsock->tx_lock);
381 }
382 dev_warn(disk_to_dev(nbd->disk), "shutting down sockets\n");
383 }
384
req_to_nbd_cmd_type(struct request * req)385 static u32 req_to_nbd_cmd_type(struct request *req)
386 {
387 switch (req_op(req)) {
388 case REQ_OP_DISCARD:
389 return NBD_CMD_TRIM;
390 case REQ_OP_FLUSH:
391 return NBD_CMD_FLUSH;
392 case REQ_OP_WRITE:
393 return NBD_CMD_WRITE;
394 case REQ_OP_READ:
395 return NBD_CMD_READ;
396 default:
397 return U32_MAX;
398 }
399 }
400
nbd_xmit_timeout(struct request * req,bool reserved)401 static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
402 bool reserved)
403 {
404 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
405 struct nbd_device *nbd = cmd->nbd;
406 struct nbd_config *config;
407
408 if (!mutex_trylock(&cmd->lock))
409 return BLK_EH_RESET_TIMER;
410
411 if (!refcount_inc_not_zero(&nbd->config_refs)) {
412 cmd->status = BLK_STS_TIMEOUT;
413 mutex_unlock(&cmd->lock);
414 goto done;
415 }
416 config = nbd->config;
417
418 if (config->num_connections > 1 ||
419 (config->num_connections == 1 && nbd->tag_set.timeout)) {
420 dev_err_ratelimited(nbd_to_dev(nbd),
421 "Connection timed out, retrying (%d/%d alive)\n",
422 atomic_read(&config->live_connections),
423 config->num_connections);
424 /*
425 * Hooray we have more connections, requeue this IO, the submit
426 * path will put it on a real connection. Or if only one
427 * connection is configured, the submit path will wait util
428 * a new connection is reconfigured or util dead timeout.
429 */
430 if (config->socks) {
431 if (cmd->index < config->num_connections) {
432 struct nbd_sock *nsock =
433 config->socks[cmd->index];
434 mutex_lock(&nsock->tx_lock);
435 /* We can have multiple outstanding requests, so
436 * we don't want to mark the nsock dead if we've
437 * already reconnected with a new socket, so
438 * only mark it dead if its the same socket we
439 * were sent out on.
440 */
441 if (cmd->cookie == nsock->cookie)
442 nbd_mark_nsock_dead(nbd, nsock, 1);
443 mutex_unlock(&nsock->tx_lock);
444 }
445 mutex_unlock(&cmd->lock);
446 nbd_requeue_cmd(cmd);
447 nbd_config_put(nbd);
448 return BLK_EH_DONE;
449 }
450 }
451
452 if (!nbd->tag_set.timeout) {
453 /*
454 * Userspace sets timeout=0 to disable socket disconnection,
455 * so just warn and reset the timer.
456 */
457 struct nbd_sock *nsock = config->socks[cmd->index];
458 cmd->retries++;
459 dev_info(nbd_to_dev(nbd), "Possible stuck request %p: control (%s@%llu,%uB). Runtime %u seconds\n",
460 req, nbdcmd_to_ascii(req_to_nbd_cmd_type(req)),
461 (unsigned long long)blk_rq_pos(req) << 9,
462 blk_rq_bytes(req), (req->timeout / HZ) * cmd->retries);
463
464 mutex_lock(&nsock->tx_lock);
465 if (cmd->cookie != nsock->cookie) {
466 nbd_requeue_cmd(cmd);
467 mutex_unlock(&nsock->tx_lock);
468 mutex_unlock(&cmd->lock);
469 nbd_config_put(nbd);
470 return BLK_EH_DONE;
471 }
472 mutex_unlock(&nsock->tx_lock);
473 mutex_unlock(&cmd->lock);
474 nbd_config_put(nbd);
475 return BLK_EH_RESET_TIMER;
476 }
477
478 dev_err_ratelimited(nbd_to_dev(nbd), "Connection timed out\n");
479 set_bit(NBD_RT_TIMEDOUT, &config->runtime_flags);
480 cmd->status = BLK_STS_IOERR;
481 mutex_unlock(&cmd->lock);
482 sock_shutdown(nbd);
483 nbd_config_put(nbd);
484 done:
485 blk_mq_complete_request(req);
486 return BLK_EH_DONE;
487 }
488
489 /*
490 * Send or receive packet.
491 */
sock_xmit(struct nbd_device * nbd,int index,int send,struct iov_iter * iter,int msg_flags,int * sent)492 static int sock_xmit(struct nbd_device *nbd, int index, int send,
493 struct iov_iter *iter, int msg_flags, int *sent)
494 {
495 struct nbd_config *config = nbd->config;
496 struct socket *sock = config->socks[index]->sock;
497 int result;
498 struct msghdr msg;
499 unsigned int noreclaim_flag;
500
501 if (unlikely(!sock)) {
502 dev_err_ratelimited(disk_to_dev(nbd->disk),
503 "Attempted %s on closed socket in sock_xmit\n",
504 (send ? "send" : "recv"));
505 return -EINVAL;
506 }
507
508 msg.msg_iter = *iter;
509
510 noreclaim_flag = memalloc_noreclaim_save();
511 do {
512 sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC;
513 msg.msg_name = NULL;
514 msg.msg_namelen = 0;
515 msg.msg_control = NULL;
516 msg.msg_controllen = 0;
517 msg.msg_flags = msg_flags | MSG_NOSIGNAL;
518
519 if (send)
520 result = sock_sendmsg(sock, &msg);
521 else
522 result = sock_recvmsg(sock, &msg, msg.msg_flags);
523
524 if (result <= 0) {
525 if (result == 0)
526 result = -EPIPE; /* short read */
527 break;
528 }
529 if (sent)
530 *sent += result;
531 } while (msg_data_left(&msg));
532
533 memalloc_noreclaim_restore(noreclaim_flag);
534
535 return result;
536 }
537
538 /*
539 * Different settings for sk->sk_sndtimeo can result in different return values
540 * if there is a signal pending when we enter sendmsg, because reasons?
541 */
was_interrupted(int result)542 static inline int was_interrupted(int result)
543 {
544 return result == -ERESTARTSYS || result == -EINTR;
545 }
546
547 /* always call with the tx_lock held */
nbd_send_cmd(struct nbd_device * nbd,struct nbd_cmd * cmd,int index)548 static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
549 {
550 struct request *req = blk_mq_rq_from_pdu(cmd);
551 struct nbd_config *config = nbd->config;
552 struct nbd_sock *nsock = config->socks[index];
553 int result;
554 struct nbd_request request = {.magic = htonl(NBD_REQUEST_MAGIC)};
555 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
556 struct iov_iter from;
557 unsigned long size = blk_rq_bytes(req);
558 struct bio *bio;
559 u64 handle;
560 u32 type;
561 u32 nbd_cmd_flags = 0;
562 int sent = nsock->sent, skip = 0;
563
564 iov_iter_kvec(&from, WRITE, &iov, 1, sizeof(request));
565
566 type = req_to_nbd_cmd_type(req);
567 if (type == U32_MAX)
568 return -EIO;
569
570 if (rq_data_dir(req) == WRITE &&
571 (config->flags & NBD_FLAG_READ_ONLY)) {
572 dev_err_ratelimited(disk_to_dev(nbd->disk),
573 "Write on read-only\n");
574 return -EIO;
575 }
576
577 if (req->cmd_flags & REQ_FUA)
578 nbd_cmd_flags |= NBD_CMD_FLAG_FUA;
579
580 /* We did a partial send previously, and we at least sent the whole
581 * request struct, so just go and send the rest of the pages in the
582 * request.
583 */
584 if (sent) {
585 if (sent >= sizeof(request)) {
586 skip = sent - sizeof(request);
587
588 /* initialize handle for tracing purposes */
589 handle = nbd_cmd_handle(cmd);
590
591 goto send_pages;
592 }
593 iov_iter_advance(&from, sent);
594 } else {
595 cmd->cmd_cookie++;
596 }
597 cmd->index = index;
598 cmd->cookie = nsock->cookie;
599 cmd->retries = 0;
600 request.type = htonl(type | nbd_cmd_flags);
601 if (type != NBD_CMD_FLUSH) {
602 request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
603 request.len = htonl(size);
604 }
605 handle = nbd_cmd_handle(cmd);
606 memcpy(request.handle, &handle, sizeof(handle));
607
608 trace_nbd_send_request(&request, nbd->index, blk_mq_rq_from_pdu(cmd));
609
610 dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n",
611 req, nbdcmd_to_ascii(type),
612 (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req));
613 result = sock_xmit(nbd, index, 1, &from,
614 (type == NBD_CMD_WRITE) ? MSG_MORE : 0, &sent);
615 trace_nbd_header_sent(req, handle);
616 if (result <= 0) {
617 if (was_interrupted(result)) {
618 /* If we havne't sent anything we can just return BUSY,
619 * however if we have sent something we need to make
620 * sure we only allow this req to be sent until we are
621 * completely done.
622 */
623 if (sent) {
624 nsock->pending = req;
625 nsock->sent = sent;
626 }
627 set_bit(NBD_CMD_REQUEUED, &cmd->flags);
628 return BLK_STS_RESOURCE;
629 }
630 dev_err_ratelimited(disk_to_dev(nbd->disk),
631 "Send control failed (result %d)\n", result);
632 return -EAGAIN;
633 }
634 send_pages:
635 if (type != NBD_CMD_WRITE)
636 goto out;
637
638 bio = req->bio;
639 while (bio) {
640 struct bio *next = bio->bi_next;
641 struct bvec_iter iter;
642 struct bio_vec bvec;
643
644 bio_for_each_segment(bvec, bio, iter) {
645 bool is_last = !next && bio_iter_last(bvec, iter);
646 int flags = is_last ? 0 : MSG_MORE;
647
648 dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n",
649 req, bvec.bv_len);
650 iov_iter_bvec(&from, WRITE, &bvec, 1, bvec.bv_len);
651 if (skip) {
652 if (skip >= iov_iter_count(&from)) {
653 skip -= iov_iter_count(&from);
654 continue;
655 }
656 iov_iter_advance(&from, skip);
657 skip = 0;
658 }
659 result = sock_xmit(nbd, index, 1, &from, flags, &sent);
660 if (result <= 0) {
661 if (was_interrupted(result)) {
662 /* We've already sent the header, we
663 * have no choice but to set pending and
664 * return BUSY.
665 */
666 nsock->pending = req;
667 nsock->sent = sent;
668 set_bit(NBD_CMD_REQUEUED, &cmd->flags);
669 return BLK_STS_RESOURCE;
670 }
671 dev_err(disk_to_dev(nbd->disk),
672 "Send data failed (result %d)\n",
673 result);
674 return -EAGAIN;
675 }
676 /*
677 * The completion might already have come in,
678 * so break for the last one instead of letting
679 * the iterator do it. This prevents use-after-free
680 * of the bio.
681 */
682 if (is_last)
683 break;
684 }
685 bio = next;
686 }
687 out:
688 trace_nbd_payload_sent(req, handle);
689 nsock->pending = NULL;
690 nsock->sent = 0;
691 return 0;
692 }
693
694 /* NULL returned = something went wrong, inform userspace */
nbd_read_stat(struct nbd_device * nbd,int index)695 static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
696 {
697 struct nbd_config *config = nbd->config;
698 int result;
699 struct nbd_reply reply;
700 struct nbd_cmd *cmd;
701 struct request *req = NULL;
702 u64 handle;
703 u16 hwq;
704 u32 tag;
705 struct kvec iov = {.iov_base = &reply, .iov_len = sizeof(reply)};
706 struct iov_iter to;
707 int ret = 0;
708
709 reply.magic = 0;
710 iov_iter_kvec(&to, READ, &iov, 1, sizeof(reply));
711 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
712 if (result <= 0) {
713 if (!nbd_disconnected(config))
714 dev_err(disk_to_dev(nbd->disk),
715 "Receive control failed (result %d)\n", result);
716 return ERR_PTR(result);
717 }
718
719 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) {
720 dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n",
721 (unsigned long)ntohl(reply.magic));
722 return ERR_PTR(-EPROTO);
723 }
724
725 memcpy(&handle, reply.handle, sizeof(handle));
726 tag = nbd_handle_to_tag(handle);
727 hwq = blk_mq_unique_tag_to_hwq(tag);
728 if (hwq < nbd->tag_set.nr_hw_queues)
729 req = blk_mq_tag_to_rq(nbd->tag_set.tags[hwq],
730 blk_mq_unique_tag_to_tag(tag));
731 if (!req || !blk_mq_request_started(req)) {
732 dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%d) %p\n",
733 tag, req);
734 return ERR_PTR(-ENOENT);
735 }
736 trace_nbd_header_received(req, handle);
737 cmd = blk_mq_rq_to_pdu(req);
738
739 mutex_lock(&cmd->lock);
740 if (cmd->cmd_cookie != nbd_handle_to_cookie(handle)) {
741 dev_err(disk_to_dev(nbd->disk), "Double reply on req %p, cmd_cookie %u, handle cookie %u\n",
742 req, cmd->cmd_cookie, nbd_handle_to_cookie(handle));
743 ret = -ENOENT;
744 goto out;
745 }
746 if (cmd->status != BLK_STS_OK) {
747 dev_err(disk_to_dev(nbd->disk), "Command already handled %p\n",
748 req);
749 ret = -ENOENT;
750 goto out;
751 }
752 if (test_bit(NBD_CMD_REQUEUED, &cmd->flags)) {
753 dev_err(disk_to_dev(nbd->disk), "Raced with timeout on req %p\n",
754 req);
755 ret = -ENOENT;
756 goto out;
757 }
758 if (ntohl(reply.error)) {
759 dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n",
760 ntohl(reply.error));
761 cmd->status = BLK_STS_IOERR;
762 goto out;
763 }
764
765 dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", req);
766 if (rq_data_dir(req) != WRITE) {
767 struct req_iterator iter;
768 struct bio_vec bvec;
769
770 rq_for_each_segment(bvec, req, iter) {
771 iov_iter_bvec(&to, READ, &bvec, 1, bvec.bv_len);
772 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
773 if (result <= 0) {
774 dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
775 result);
776 /*
777 * If we've disconnected, we need to make sure we
778 * complete this request, otherwise error out
779 * and let the timeout stuff handle resubmitting
780 * this request onto another connection.
781 */
782 if (nbd_disconnected(config)) {
783 cmd->status = BLK_STS_IOERR;
784 goto out;
785 }
786 ret = -EIO;
787 goto out;
788 }
789 dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n",
790 req, bvec.bv_len);
791 }
792 }
793 out:
794 trace_nbd_payload_received(req, handle);
795 mutex_unlock(&cmd->lock);
796 return ret ? ERR_PTR(ret) : cmd;
797 }
798
recv_work(struct work_struct * work)799 static void recv_work(struct work_struct *work)
800 {
801 struct recv_thread_args *args = container_of(work,
802 struct recv_thread_args,
803 work);
804 struct nbd_device *nbd = args->nbd;
805 struct nbd_config *config = nbd->config;
806 struct nbd_cmd *cmd;
807 struct request *rq;
808
809 while (1) {
810 cmd = nbd_read_stat(nbd, args->index);
811 if (IS_ERR(cmd)) {
812 struct nbd_sock *nsock = config->socks[args->index];
813
814 mutex_lock(&nsock->tx_lock);
815 nbd_mark_nsock_dead(nbd, nsock, 1);
816 mutex_unlock(&nsock->tx_lock);
817 break;
818 }
819
820 rq = blk_mq_rq_from_pdu(cmd);
821 if (likely(!blk_should_fake_timeout(rq->q)))
822 blk_mq_complete_request(rq);
823 }
824 nbd_config_put(nbd);
825 atomic_dec(&config->recv_threads);
826 wake_up(&config->recv_wq);
827 kfree(args);
828 }
829
nbd_clear_req(struct request * req,void * data,bool reserved)830 static bool nbd_clear_req(struct request *req, void *data, bool reserved)
831 {
832 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
833
834 /* don't abort one completed request */
835 if (blk_mq_request_completed(req))
836 return true;
837
838 mutex_lock(&cmd->lock);
839 cmd->status = BLK_STS_IOERR;
840 mutex_unlock(&cmd->lock);
841
842 blk_mq_complete_request(req);
843 return true;
844 }
845
nbd_clear_que(struct nbd_device * nbd)846 static void nbd_clear_que(struct nbd_device *nbd)
847 {
848 blk_mq_quiesce_queue(nbd->disk->queue);
849 blk_mq_tagset_busy_iter(&nbd->tag_set, nbd_clear_req, NULL);
850 blk_mq_unquiesce_queue(nbd->disk->queue);
851 dev_dbg(disk_to_dev(nbd->disk), "queue cleared\n");
852 }
853
find_fallback(struct nbd_device * nbd,int index)854 static int find_fallback(struct nbd_device *nbd, int index)
855 {
856 struct nbd_config *config = nbd->config;
857 int new_index = -1;
858 struct nbd_sock *nsock = config->socks[index];
859 int fallback = nsock->fallback_index;
860
861 if (test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags))
862 return new_index;
863
864 if (config->num_connections <= 1) {
865 dev_err_ratelimited(disk_to_dev(nbd->disk),
866 "Dead connection, failed to find a fallback\n");
867 return new_index;
868 }
869
870 if (fallback >= 0 && fallback < config->num_connections &&
871 !config->socks[fallback]->dead)
872 return fallback;
873
874 if (nsock->fallback_index < 0 ||
875 nsock->fallback_index >= config->num_connections ||
876 config->socks[nsock->fallback_index]->dead) {
877 int i;
878 for (i = 0; i < config->num_connections; i++) {
879 if (i == index)
880 continue;
881 if (!config->socks[i]->dead) {
882 new_index = i;
883 break;
884 }
885 }
886 nsock->fallback_index = new_index;
887 if (new_index < 0) {
888 dev_err_ratelimited(disk_to_dev(nbd->disk),
889 "Dead connection, failed to find a fallback\n");
890 return new_index;
891 }
892 }
893 new_index = nsock->fallback_index;
894 return new_index;
895 }
896
wait_for_reconnect(struct nbd_device * nbd)897 static int wait_for_reconnect(struct nbd_device *nbd)
898 {
899 struct nbd_config *config = nbd->config;
900 if (!config->dead_conn_timeout)
901 return 0;
902
903 if (!wait_event_timeout(config->conn_wait,
904 test_bit(NBD_RT_DISCONNECTED,
905 &config->runtime_flags) ||
906 atomic_read(&config->live_connections) > 0,
907 config->dead_conn_timeout))
908 return 0;
909
910 return !test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags);
911 }
912
nbd_handle_cmd(struct nbd_cmd * cmd,int index)913 static int nbd_handle_cmd(struct nbd_cmd *cmd, int index)
914 {
915 struct request *req = blk_mq_rq_from_pdu(cmd);
916 struct nbd_device *nbd = cmd->nbd;
917 struct nbd_config *config;
918 struct nbd_sock *nsock;
919 int ret;
920
921 if (!refcount_inc_not_zero(&nbd->config_refs)) {
922 dev_err_ratelimited(disk_to_dev(nbd->disk),
923 "Socks array is empty\n");
924 blk_mq_start_request(req);
925 return -EINVAL;
926 }
927 config = nbd->config;
928
929 if (index >= config->num_connections) {
930 dev_err_ratelimited(disk_to_dev(nbd->disk),
931 "Attempted send on invalid socket\n");
932 nbd_config_put(nbd);
933 blk_mq_start_request(req);
934 return -EINVAL;
935 }
936 cmd->status = BLK_STS_OK;
937 again:
938 nsock = config->socks[index];
939 mutex_lock(&nsock->tx_lock);
940 if (nsock->dead) {
941 int old_index = index;
942 index = find_fallback(nbd, index);
943 mutex_unlock(&nsock->tx_lock);
944 if (index < 0) {
945 if (wait_for_reconnect(nbd)) {
946 index = old_index;
947 goto again;
948 }
949 /* All the sockets should already be down at this point,
950 * we just want to make sure that DISCONNECTED is set so
951 * any requests that come in that were queue'ed waiting
952 * for the reconnect timer don't trigger the timer again
953 * and instead just error out.
954 */
955 sock_shutdown(nbd);
956 nbd_config_put(nbd);
957 blk_mq_start_request(req);
958 return -EIO;
959 }
960 goto again;
961 }
962
963 /* Handle the case that we have a pending request that was partially
964 * transmitted that _has_ to be serviced first. We need to call requeue
965 * here so that it gets put _after_ the request that is already on the
966 * dispatch list.
967 */
968 blk_mq_start_request(req);
969 if (unlikely(nsock->pending && nsock->pending != req)) {
970 nbd_requeue_cmd(cmd);
971 ret = 0;
972 goto out;
973 }
974 /*
975 * Some failures are related to the link going down, so anything that
976 * returns EAGAIN can be retried on a different socket.
977 */
978 ret = nbd_send_cmd(nbd, cmd, index);
979 if (ret == -EAGAIN) {
980 dev_err_ratelimited(disk_to_dev(nbd->disk),
981 "Request send failed, requeueing\n");
982 nbd_mark_nsock_dead(nbd, nsock, 1);
983 nbd_requeue_cmd(cmd);
984 ret = 0;
985 }
986 out:
987 mutex_unlock(&nsock->tx_lock);
988 nbd_config_put(nbd);
989 return ret;
990 }
991
nbd_queue_rq(struct blk_mq_hw_ctx * hctx,const struct blk_mq_queue_data * bd)992 static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
993 const struct blk_mq_queue_data *bd)
994 {
995 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
996 int ret;
997
998 /*
999 * Since we look at the bio's to send the request over the network we
1000 * need to make sure the completion work doesn't mark this request done
1001 * before we are done doing our send. This keeps us from dereferencing
1002 * freed data if we have particularly fast completions (ie we get the
1003 * completion before we exit sock_xmit on the last bvec) or in the case
1004 * that the server is misbehaving (or there was an error) before we're
1005 * done sending everything over the wire.
1006 */
1007 mutex_lock(&cmd->lock);
1008 clear_bit(NBD_CMD_REQUEUED, &cmd->flags);
1009
1010 /* We can be called directly from the user space process, which means we
1011 * could possibly have signals pending so our sendmsg will fail. In
1012 * this case we need to return that we are busy, otherwise error out as
1013 * appropriate.
1014 */
1015 ret = nbd_handle_cmd(cmd, hctx->queue_num);
1016 if (ret < 0)
1017 ret = BLK_STS_IOERR;
1018 else if (!ret)
1019 ret = BLK_STS_OK;
1020 mutex_unlock(&cmd->lock);
1021
1022 return ret;
1023 }
1024
nbd_get_socket(struct nbd_device * nbd,unsigned long fd,int * err)1025 static struct socket *nbd_get_socket(struct nbd_device *nbd, unsigned long fd,
1026 int *err)
1027 {
1028 struct socket *sock;
1029
1030 *err = 0;
1031 sock = sockfd_lookup(fd, err);
1032 if (!sock)
1033 return NULL;
1034
1035 if (sock->ops->shutdown == sock_no_shutdown) {
1036 dev_err(disk_to_dev(nbd->disk), "Unsupported socket: shutdown callout must be supported.\n");
1037 *err = -EINVAL;
1038 sockfd_put(sock);
1039 return NULL;
1040 }
1041
1042 return sock;
1043 }
1044
nbd_add_socket(struct nbd_device * nbd,unsigned long arg,bool netlink)1045 static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
1046 bool netlink)
1047 {
1048 struct nbd_config *config = nbd->config;
1049 struct socket *sock;
1050 struct nbd_sock **socks;
1051 struct nbd_sock *nsock;
1052 int err;
1053
1054 /* Arg will be cast to int, check it to avoid overflow */
1055 if (arg > INT_MAX)
1056 return -EINVAL;
1057 sock = nbd_get_socket(nbd, arg, &err);
1058 if (!sock)
1059 return err;
1060
1061 /*
1062 * We need to make sure we don't get any errant requests while we're
1063 * reallocating the ->socks array.
1064 */
1065 blk_mq_freeze_queue(nbd->disk->queue);
1066
1067 if (!netlink && !nbd->task_setup &&
1068 !test_bit(NBD_RT_BOUND, &config->runtime_flags))
1069 nbd->task_setup = current;
1070
1071 if (!netlink &&
1072 (nbd->task_setup != current ||
1073 test_bit(NBD_RT_BOUND, &config->runtime_flags))) {
1074 dev_err(disk_to_dev(nbd->disk),
1075 "Device being setup by another task");
1076 err = -EBUSY;
1077 goto put_socket;
1078 }
1079
1080 nsock = kzalloc(sizeof(*nsock), GFP_KERNEL);
1081 if (!nsock) {
1082 err = -ENOMEM;
1083 goto put_socket;
1084 }
1085
1086 socks = krealloc(config->socks, (config->num_connections + 1) *
1087 sizeof(struct nbd_sock *), GFP_KERNEL);
1088 if (!socks) {
1089 kfree(nsock);
1090 err = -ENOMEM;
1091 goto put_socket;
1092 }
1093
1094 config->socks = socks;
1095
1096 nsock->fallback_index = -1;
1097 nsock->dead = false;
1098 mutex_init(&nsock->tx_lock);
1099 nsock->sock = sock;
1100 nsock->pending = NULL;
1101 nsock->sent = 0;
1102 nsock->cookie = 0;
1103 socks[config->num_connections++] = nsock;
1104 atomic_inc(&config->live_connections);
1105 blk_mq_unfreeze_queue(nbd->disk->queue);
1106
1107 return 0;
1108
1109 put_socket:
1110 blk_mq_unfreeze_queue(nbd->disk->queue);
1111 sockfd_put(sock);
1112 return err;
1113 }
1114
nbd_reconnect_socket(struct nbd_device * nbd,unsigned long arg)1115 static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg)
1116 {
1117 struct nbd_config *config = nbd->config;
1118 struct socket *sock, *old;
1119 struct recv_thread_args *args;
1120 int i;
1121 int err;
1122
1123 sock = nbd_get_socket(nbd, arg, &err);
1124 if (!sock)
1125 return err;
1126
1127 args = kzalloc(sizeof(*args), GFP_KERNEL);
1128 if (!args) {
1129 sockfd_put(sock);
1130 return -ENOMEM;
1131 }
1132
1133 for (i = 0; i < config->num_connections; i++) {
1134 struct nbd_sock *nsock = config->socks[i];
1135
1136 if (!nsock->dead)
1137 continue;
1138
1139 mutex_lock(&nsock->tx_lock);
1140 if (!nsock->dead) {
1141 mutex_unlock(&nsock->tx_lock);
1142 continue;
1143 }
1144 sk_set_memalloc(sock->sk);
1145 if (nbd->tag_set.timeout)
1146 sock->sk->sk_sndtimeo = nbd->tag_set.timeout;
1147 atomic_inc(&config->recv_threads);
1148 refcount_inc(&nbd->config_refs);
1149 old = nsock->sock;
1150 nsock->fallback_index = -1;
1151 nsock->sock = sock;
1152 nsock->dead = false;
1153 INIT_WORK(&args->work, recv_work);
1154 args->index = i;
1155 args->nbd = nbd;
1156 nsock->cookie++;
1157 mutex_unlock(&nsock->tx_lock);
1158 sockfd_put(old);
1159
1160 clear_bit(NBD_RT_DISCONNECTED, &config->runtime_flags);
1161
1162 /* We take the tx_mutex in an error path in the recv_work, so we
1163 * need to queue_work outside of the tx_mutex.
1164 */
1165 queue_work(nbd->recv_workq, &args->work);
1166
1167 atomic_inc(&config->live_connections);
1168 wake_up(&config->conn_wait);
1169 return 0;
1170 }
1171 sockfd_put(sock);
1172 kfree(args);
1173 return -ENOSPC;
1174 }
1175
nbd_bdev_reset(struct nbd_device * nbd)1176 static void nbd_bdev_reset(struct nbd_device *nbd)
1177 {
1178 if (nbd->disk->part0->bd_openers > 1)
1179 return;
1180 set_capacity(nbd->disk, 0);
1181 }
1182
nbd_parse_flags(struct nbd_device * nbd)1183 static void nbd_parse_flags(struct nbd_device *nbd)
1184 {
1185 struct nbd_config *config = nbd->config;
1186 if (config->flags & NBD_FLAG_READ_ONLY)
1187 set_disk_ro(nbd->disk, true);
1188 else
1189 set_disk_ro(nbd->disk, false);
1190 if (config->flags & NBD_FLAG_SEND_TRIM)
1191 blk_queue_flag_set(QUEUE_FLAG_DISCARD, nbd->disk->queue);
1192 if (config->flags & NBD_FLAG_SEND_FLUSH) {
1193 if (config->flags & NBD_FLAG_SEND_FUA)
1194 blk_queue_write_cache(nbd->disk->queue, true, true);
1195 else
1196 blk_queue_write_cache(nbd->disk->queue, true, false);
1197 }
1198 else
1199 blk_queue_write_cache(nbd->disk->queue, false, false);
1200 }
1201
send_disconnects(struct nbd_device * nbd)1202 static void send_disconnects(struct nbd_device *nbd)
1203 {
1204 struct nbd_config *config = nbd->config;
1205 struct nbd_request request = {
1206 .magic = htonl(NBD_REQUEST_MAGIC),
1207 .type = htonl(NBD_CMD_DISC),
1208 };
1209 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
1210 struct iov_iter from;
1211 int i, ret;
1212
1213 for (i = 0; i < config->num_connections; i++) {
1214 struct nbd_sock *nsock = config->socks[i];
1215
1216 iov_iter_kvec(&from, WRITE, &iov, 1, sizeof(request));
1217 mutex_lock(&nsock->tx_lock);
1218 ret = sock_xmit(nbd, i, 1, &from, 0, NULL);
1219 if (ret <= 0)
1220 dev_err(disk_to_dev(nbd->disk),
1221 "Send disconnect failed %d\n", ret);
1222 mutex_unlock(&nsock->tx_lock);
1223 }
1224 }
1225
nbd_disconnect(struct nbd_device * nbd)1226 static int nbd_disconnect(struct nbd_device *nbd)
1227 {
1228 struct nbd_config *config = nbd->config;
1229
1230 dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
1231 set_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags);
1232 set_bit(NBD_DISCONNECT_REQUESTED, &nbd->flags);
1233 send_disconnects(nbd);
1234 return 0;
1235 }
1236
nbd_clear_sock(struct nbd_device * nbd)1237 static void nbd_clear_sock(struct nbd_device *nbd)
1238 {
1239 sock_shutdown(nbd);
1240 nbd_clear_que(nbd);
1241 nbd->task_setup = NULL;
1242 }
1243
nbd_config_put(struct nbd_device * nbd)1244 static void nbd_config_put(struct nbd_device *nbd)
1245 {
1246 if (refcount_dec_and_mutex_lock(&nbd->config_refs,
1247 &nbd->config_lock)) {
1248 struct nbd_config *config = nbd->config;
1249 nbd_dev_dbg_close(nbd);
1250 nbd_size_clear(nbd);
1251 if (test_and_clear_bit(NBD_RT_HAS_PID_FILE,
1252 &config->runtime_flags))
1253 device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
1254 nbd->pid = 0;
1255 if (test_and_clear_bit(NBD_RT_HAS_BACKEND_FILE,
1256 &config->runtime_flags)) {
1257 device_remove_file(disk_to_dev(nbd->disk), &backend_attr);
1258 kfree(nbd->backend);
1259 nbd->backend = NULL;
1260 }
1261 nbd_clear_sock(nbd);
1262 if (config->num_connections) {
1263 int i;
1264 for (i = 0; i < config->num_connections; i++) {
1265 sockfd_put(config->socks[i]->sock);
1266 kfree(config->socks[i]);
1267 }
1268 kfree(config->socks);
1269 }
1270 kfree(nbd->config);
1271 nbd->config = NULL;
1272
1273 nbd->tag_set.timeout = 0;
1274 nbd->disk->queue->limits.discard_granularity = 0;
1275 nbd->disk->queue->limits.discard_alignment = 0;
1276 blk_queue_max_discard_sectors(nbd->disk->queue, UINT_MAX);
1277 blk_queue_flag_clear(QUEUE_FLAG_DISCARD, nbd->disk->queue);
1278
1279 mutex_unlock(&nbd->config_lock);
1280 nbd_put(nbd);
1281 module_put(THIS_MODULE);
1282 }
1283 }
1284
nbd_start_device(struct nbd_device * nbd)1285 static int nbd_start_device(struct nbd_device *nbd)
1286 {
1287 struct nbd_config *config = nbd->config;
1288 int num_connections = config->num_connections;
1289 int error = 0, i;
1290
1291 if (nbd->pid)
1292 return -EBUSY;
1293 if (!config->socks)
1294 return -EINVAL;
1295 if (num_connections > 1 &&
1296 !(config->flags & NBD_FLAG_CAN_MULTI_CONN)) {
1297 dev_err(disk_to_dev(nbd->disk), "server does not support multiple connections per device.\n");
1298 return -EINVAL;
1299 }
1300
1301 blk_mq_update_nr_hw_queues(&nbd->tag_set, config->num_connections);
1302 nbd->pid = task_pid_nr(current);
1303
1304 nbd_parse_flags(nbd);
1305
1306 error = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
1307 if (error) {
1308 dev_err(disk_to_dev(nbd->disk), "device_create_file failed for pid!\n");
1309 return error;
1310 }
1311 set_bit(NBD_RT_HAS_PID_FILE, &config->runtime_flags);
1312
1313 nbd_dev_dbg_init(nbd);
1314 for (i = 0; i < num_connections; i++) {
1315 struct recv_thread_args *args;
1316
1317 args = kzalloc(sizeof(*args), GFP_KERNEL);
1318 if (!args) {
1319 sock_shutdown(nbd);
1320 /*
1321 * If num_connections is m (2 < m),
1322 * and NO.1 ~ NO.n(1 < n < m) kzallocs are successful.
1323 * But NO.(n + 1) failed. We still have n recv threads.
1324 * So, add flush_workqueue here to prevent recv threads
1325 * dropping the last config_refs and trying to destroy
1326 * the workqueue from inside the workqueue.
1327 */
1328 if (i)
1329 flush_workqueue(nbd->recv_workq);
1330 return -ENOMEM;
1331 }
1332 sk_set_memalloc(config->socks[i]->sock->sk);
1333 if (nbd->tag_set.timeout)
1334 config->socks[i]->sock->sk->sk_sndtimeo =
1335 nbd->tag_set.timeout;
1336 atomic_inc(&config->recv_threads);
1337 refcount_inc(&nbd->config_refs);
1338 INIT_WORK(&args->work, recv_work);
1339 args->nbd = nbd;
1340 args->index = i;
1341 queue_work(nbd->recv_workq, &args->work);
1342 }
1343 return nbd_set_size(nbd, config->bytesize, nbd_blksize(config));
1344 }
1345
nbd_start_device_ioctl(struct nbd_device * nbd)1346 static int nbd_start_device_ioctl(struct nbd_device *nbd)
1347 {
1348 struct nbd_config *config = nbd->config;
1349 int ret;
1350
1351 ret = nbd_start_device(nbd);
1352 if (ret)
1353 return ret;
1354
1355 if (max_part)
1356 set_bit(GD_NEED_PART_SCAN, &nbd->disk->state);
1357 mutex_unlock(&nbd->config_lock);
1358 ret = wait_event_interruptible(config->recv_wq,
1359 atomic_read(&config->recv_threads) == 0);
1360 if (ret) {
1361 sock_shutdown(nbd);
1362 nbd_clear_que(nbd);
1363 }
1364
1365 flush_workqueue(nbd->recv_workq);
1366 mutex_lock(&nbd->config_lock);
1367 nbd_bdev_reset(nbd);
1368 /* user requested, ignore socket errors */
1369 if (test_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags))
1370 ret = 0;
1371 if (test_bit(NBD_RT_TIMEDOUT, &config->runtime_flags))
1372 ret = -ETIMEDOUT;
1373 return ret;
1374 }
1375
nbd_clear_sock_ioctl(struct nbd_device * nbd,struct block_device * bdev)1376 static void nbd_clear_sock_ioctl(struct nbd_device *nbd,
1377 struct block_device *bdev)
1378 {
1379 nbd_clear_sock(nbd);
1380 __invalidate_device(bdev, true);
1381 nbd_bdev_reset(nbd);
1382 if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF,
1383 &nbd->config->runtime_flags))
1384 nbd_config_put(nbd);
1385 }
1386
nbd_set_cmd_timeout(struct nbd_device * nbd,u64 timeout)1387 static void nbd_set_cmd_timeout(struct nbd_device *nbd, u64 timeout)
1388 {
1389 nbd->tag_set.timeout = timeout * HZ;
1390 if (timeout)
1391 blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ);
1392 else
1393 blk_queue_rq_timeout(nbd->disk->queue, 30 * HZ);
1394 }
1395
1396 /* Must be called with config_lock held */
__nbd_ioctl(struct block_device * bdev,struct nbd_device * nbd,unsigned int cmd,unsigned long arg)1397 static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
1398 unsigned int cmd, unsigned long arg)
1399 {
1400 struct nbd_config *config = nbd->config;
1401 loff_t bytesize;
1402
1403 switch (cmd) {
1404 case NBD_DISCONNECT:
1405 return nbd_disconnect(nbd);
1406 case NBD_CLEAR_SOCK:
1407 nbd_clear_sock_ioctl(nbd, bdev);
1408 return 0;
1409 case NBD_SET_SOCK:
1410 return nbd_add_socket(nbd, arg, false);
1411 case NBD_SET_BLKSIZE:
1412 return nbd_set_size(nbd, config->bytesize, arg);
1413 case NBD_SET_SIZE:
1414 return nbd_set_size(nbd, arg, nbd_blksize(config));
1415 case NBD_SET_SIZE_BLOCKS:
1416 if (check_shl_overflow(arg, config->blksize_bits, &bytesize))
1417 return -EINVAL;
1418 return nbd_set_size(nbd, bytesize, nbd_blksize(config));
1419 case NBD_SET_TIMEOUT:
1420 nbd_set_cmd_timeout(nbd, arg);
1421 return 0;
1422
1423 case NBD_SET_FLAGS:
1424 config->flags = arg;
1425 return 0;
1426 case NBD_DO_IT:
1427 return nbd_start_device_ioctl(nbd);
1428 case NBD_CLEAR_QUE:
1429 /*
1430 * This is for compatibility only. The queue is always cleared
1431 * by NBD_DO_IT or NBD_CLEAR_SOCK.
1432 */
1433 return 0;
1434 case NBD_PRINT_DEBUG:
1435 /*
1436 * For compatibility only, we no longer keep a list of
1437 * outstanding requests.
1438 */
1439 return 0;
1440 }
1441 return -ENOTTY;
1442 }
1443
nbd_ioctl(struct block_device * bdev,fmode_t mode,unsigned int cmd,unsigned long arg)1444 static int nbd_ioctl(struct block_device *bdev, fmode_t mode,
1445 unsigned int cmd, unsigned long arg)
1446 {
1447 struct nbd_device *nbd = bdev->bd_disk->private_data;
1448 struct nbd_config *config = nbd->config;
1449 int error = -EINVAL;
1450
1451 if (!capable(CAP_SYS_ADMIN))
1452 return -EPERM;
1453
1454 /* The block layer will pass back some non-nbd ioctls in case we have
1455 * special handling for them, but we don't so just return an error.
1456 */
1457 if (_IOC_TYPE(cmd) != 0xab)
1458 return -EINVAL;
1459
1460 mutex_lock(&nbd->config_lock);
1461
1462 /* Don't allow ioctl operations on a nbd device that was created with
1463 * netlink, unless it's DISCONNECT or CLEAR_SOCK, which are fine.
1464 */
1465 if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) ||
1466 (cmd == NBD_DISCONNECT || cmd == NBD_CLEAR_SOCK))
1467 error = __nbd_ioctl(bdev, nbd, cmd, arg);
1468 else
1469 dev_err(nbd_to_dev(nbd), "Cannot use ioctl interface on a netlink controlled device.\n");
1470 mutex_unlock(&nbd->config_lock);
1471 return error;
1472 }
1473
nbd_alloc_config(void)1474 static struct nbd_config *nbd_alloc_config(void)
1475 {
1476 struct nbd_config *config;
1477
1478 if (!try_module_get(THIS_MODULE))
1479 return ERR_PTR(-ENODEV);
1480
1481 config = kzalloc(sizeof(struct nbd_config), GFP_NOFS);
1482 if (!config) {
1483 module_put(THIS_MODULE);
1484 return ERR_PTR(-ENOMEM);
1485 }
1486
1487 atomic_set(&config->recv_threads, 0);
1488 init_waitqueue_head(&config->recv_wq);
1489 init_waitqueue_head(&config->conn_wait);
1490 config->blksize_bits = NBD_DEF_BLKSIZE_BITS;
1491 atomic_set(&config->live_connections, 0);
1492 return config;
1493 }
1494
nbd_open(struct block_device * bdev,fmode_t mode)1495 static int nbd_open(struct block_device *bdev, fmode_t mode)
1496 {
1497 struct nbd_device *nbd;
1498 int ret = 0;
1499
1500 mutex_lock(&nbd_index_mutex);
1501 nbd = bdev->bd_disk->private_data;
1502 if (!nbd) {
1503 ret = -ENXIO;
1504 goto out;
1505 }
1506 if (!refcount_inc_not_zero(&nbd->refs)) {
1507 ret = -ENXIO;
1508 goto out;
1509 }
1510 if (!refcount_inc_not_zero(&nbd->config_refs)) {
1511 struct nbd_config *config;
1512
1513 mutex_lock(&nbd->config_lock);
1514 if (refcount_inc_not_zero(&nbd->config_refs)) {
1515 mutex_unlock(&nbd->config_lock);
1516 goto out;
1517 }
1518 config = nbd_alloc_config();
1519 if (IS_ERR(config)) {
1520 ret = PTR_ERR(config);
1521 mutex_unlock(&nbd->config_lock);
1522 goto out;
1523 }
1524 nbd->config = config;
1525 refcount_set(&nbd->config_refs, 1);
1526 refcount_inc(&nbd->refs);
1527 mutex_unlock(&nbd->config_lock);
1528 if (max_part)
1529 set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
1530 } else if (nbd_disconnected(nbd->config)) {
1531 if (max_part)
1532 set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
1533 }
1534 out:
1535 mutex_unlock(&nbd_index_mutex);
1536 return ret;
1537 }
1538
nbd_release(struct gendisk * disk,fmode_t mode)1539 static void nbd_release(struct gendisk *disk, fmode_t mode)
1540 {
1541 struct nbd_device *nbd = disk->private_data;
1542
1543 if (test_bit(NBD_RT_DISCONNECT_ON_CLOSE, &nbd->config->runtime_flags) &&
1544 disk->part0->bd_openers == 0)
1545 nbd_disconnect_and_put(nbd);
1546
1547 nbd_config_put(nbd);
1548 nbd_put(nbd);
1549 }
1550
1551 static const struct block_device_operations nbd_fops =
1552 {
1553 .owner = THIS_MODULE,
1554 .open = nbd_open,
1555 .release = nbd_release,
1556 .ioctl = nbd_ioctl,
1557 .compat_ioctl = nbd_ioctl,
1558 };
1559
1560 #if IS_ENABLED(CONFIG_DEBUG_FS)
1561
nbd_dbg_tasks_show(struct seq_file * s,void * unused)1562 static int nbd_dbg_tasks_show(struct seq_file *s, void *unused)
1563 {
1564 struct nbd_device *nbd = s->private;
1565
1566 if (nbd->pid)
1567 seq_printf(s, "recv: %d\n", nbd->pid);
1568
1569 return 0;
1570 }
1571
1572 DEFINE_SHOW_ATTRIBUTE(nbd_dbg_tasks);
1573
nbd_dbg_flags_show(struct seq_file * s,void * unused)1574 static int nbd_dbg_flags_show(struct seq_file *s, void *unused)
1575 {
1576 struct nbd_device *nbd = s->private;
1577 u32 flags = nbd->config->flags;
1578
1579 seq_printf(s, "Hex: 0x%08x\n\n", flags);
1580
1581 seq_puts(s, "Known flags:\n");
1582
1583 if (flags & NBD_FLAG_HAS_FLAGS)
1584 seq_puts(s, "NBD_FLAG_HAS_FLAGS\n");
1585 if (flags & NBD_FLAG_READ_ONLY)
1586 seq_puts(s, "NBD_FLAG_READ_ONLY\n");
1587 if (flags & NBD_FLAG_SEND_FLUSH)
1588 seq_puts(s, "NBD_FLAG_SEND_FLUSH\n");
1589 if (flags & NBD_FLAG_SEND_FUA)
1590 seq_puts(s, "NBD_FLAG_SEND_FUA\n");
1591 if (flags & NBD_FLAG_SEND_TRIM)
1592 seq_puts(s, "NBD_FLAG_SEND_TRIM\n");
1593
1594 return 0;
1595 }
1596
1597 DEFINE_SHOW_ATTRIBUTE(nbd_dbg_flags);
1598
nbd_dev_dbg_init(struct nbd_device * nbd)1599 static int nbd_dev_dbg_init(struct nbd_device *nbd)
1600 {
1601 struct dentry *dir;
1602 struct nbd_config *config = nbd->config;
1603
1604 if (!nbd_dbg_dir)
1605 return -EIO;
1606
1607 dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir);
1608 if (IS_ERR(dir)) {
1609 dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s'\n",
1610 nbd_name(nbd));
1611 return -EIO;
1612 }
1613 config->dbg_dir = dir;
1614
1615 debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_fops);
1616 debugfs_create_u64("size_bytes", 0444, dir, &config->bytesize);
1617 debugfs_create_u32("timeout", 0444, dir, &nbd->tag_set.timeout);
1618 debugfs_create_u32("blocksize_bits", 0444, dir, &config->blksize_bits);
1619 debugfs_create_file("flags", 0444, dir, nbd, &nbd_dbg_flags_fops);
1620
1621 return 0;
1622 }
1623
nbd_dev_dbg_close(struct nbd_device * nbd)1624 static void nbd_dev_dbg_close(struct nbd_device *nbd)
1625 {
1626 debugfs_remove_recursive(nbd->config->dbg_dir);
1627 }
1628
nbd_dbg_init(void)1629 static int nbd_dbg_init(void)
1630 {
1631 struct dentry *dbg_dir;
1632
1633 dbg_dir = debugfs_create_dir("nbd", NULL);
1634 if (IS_ERR(dbg_dir))
1635 return -EIO;
1636
1637 nbd_dbg_dir = dbg_dir;
1638
1639 return 0;
1640 }
1641
nbd_dbg_close(void)1642 static void nbd_dbg_close(void)
1643 {
1644 debugfs_remove_recursive(nbd_dbg_dir);
1645 }
1646
1647 #else /* IS_ENABLED(CONFIG_DEBUG_FS) */
1648
nbd_dev_dbg_init(struct nbd_device * nbd)1649 static int nbd_dev_dbg_init(struct nbd_device *nbd)
1650 {
1651 return 0;
1652 }
1653
nbd_dev_dbg_close(struct nbd_device * nbd)1654 static void nbd_dev_dbg_close(struct nbd_device *nbd)
1655 {
1656 }
1657
nbd_dbg_init(void)1658 static int nbd_dbg_init(void)
1659 {
1660 return 0;
1661 }
1662
nbd_dbg_close(void)1663 static void nbd_dbg_close(void)
1664 {
1665 }
1666
1667 #endif
1668
nbd_init_request(struct blk_mq_tag_set * set,struct request * rq,unsigned int hctx_idx,unsigned int numa_node)1669 static int nbd_init_request(struct blk_mq_tag_set *set, struct request *rq,
1670 unsigned int hctx_idx, unsigned int numa_node)
1671 {
1672 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq);
1673 cmd->nbd = set->driver_data;
1674 cmd->flags = 0;
1675 mutex_init(&cmd->lock);
1676 return 0;
1677 }
1678
1679 static const struct blk_mq_ops nbd_mq_ops = {
1680 .queue_rq = nbd_queue_rq,
1681 .complete = nbd_complete_rq,
1682 .init_request = nbd_init_request,
1683 .timeout = nbd_xmit_timeout,
1684 };
1685
nbd_dev_add(int index,unsigned int refs)1686 static struct nbd_device *nbd_dev_add(int index, unsigned int refs)
1687 {
1688 struct nbd_device *nbd;
1689 struct gendisk *disk;
1690 int err = -ENOMEM;
1691
1692 nbd = kzalloc(sizeof(struct nbd_device), GFP_KERNEL);
1693 if (!nbd)
1694 goto out;
1695
1696 nbd->tag_set.ops = &nbd_mq_ops;
1697 nbd->tag_set.nr_hw_queues = 1;
1698 nbd->tag_set.queue_depth = 128;
1699 nbd->tag_set.numa_node = NUMA_NO_NODE;
1700 nbd->tag_set.cmd_size = sizeof(struct nbd_cmd);
1701 nbd->tag_set.flags = BLK_MQ_F_SHOULD_MERGE |
1702 BLK_MQ_F_BLOCKING;
1703 nbd->tag_set.driver_data = nbd;
1704 INIT_WORK(&nbd->remove_work, nbd_dev_remove_work);
1705 nbd->backend = NULL;
1706
1707 err = blk_mq_alloc_tag_set(&nbd->tag_set);
1708 if (err)
1709 goto out_free_nbd;
1710
1711 mutex_lock(&nbd_index_mutex);
1712 if (index >= 0) {
1713 err = idr_alloc(&nbd_index_idr, nbd, index, index + 1,
1714 GFP_KERNEL);
1715 if (err == -ENOSPC)
1716 err = -EEXIST;
1717 } else {
1718 err = idr_alloc(&nbd_index_idr, nbd, 0,
1719 (MINORMASK >> part_shift) + 1, GFP_KERNEL);
1720 if (err >= 0)
1721 index = err;
1722 }
1723 nbd->index = index;
1724 mutex_unlock(&nbd_index_mutex);
1725 if (err < 0)
1726 goto out_free_tags;
1727
1728 disk = blk_mq_alloc_disk(&nbd->tag_set, NULL);
1729 if (IS_ERR(disk)) {
1730 err = PTR_ERR(disk);
1731 goto out_free_idr;
1732 }
1733 nbd->disk = disk;
1734
1735 nbd->recv_workq = alloc_workqueue("nbd%d-recv",
1736 WQ_MEM_RECLAIM | WQ_HIGHPRI |
1737 WQ_UNBOUND, 0, nbd->index);
1738 if (!nbd->recv_workq) {
1739 dev_err(disk_to_dev(nbd->disk), "Could not allocate knbd recv work queue.\n");
1740 err = -ENOMEM;
1741 goto out_err_disk;
1742 }
1743
1744 /*
1745 * Tell the block layer that we are not a rotational device
1746 */
1747 blk_queue_flag_set(QUEUE_FLAG_NONROT, disk->queue);
1748 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, disk->queue);
1749 disk->queue->limits.discard_granularity = 0;
1750 disk->queue->limits.discard_alignment = 0;
1751 blk_queue_max_discard_sectors(disk->queue, 0);
1752 blk_queue_max_segment_size(disk->queue, UINT_MAX);
1753 blk_queue_max_segments(disk->queue, USHRT_MAX);
1754 blk_queue_max_hw_sectors(disk->queue, 65536);
1755 disk->queue->limits.max_sectors = 256;
1756
1757 mutex_init(&nbd->config_lock);
1758 refcount_set(&nbd->config_refs, 0);
1759 /*
1760 * Start out with a zero references to keep other threads from using
1761 * this device until it is fully initialized.
1762 */
1763 refcount_set(&nbd->refs, 0);
1764 INIT_LIST_HEAD(&nbd->list);
1765 disk->major = NBD_MAJOR;
1766 disk->first_minor = index << part_shift;
1767 disk->minors = 1 << part_shift;
1768 disk->fops = &nbd_fops;
1769 disk->private_data = nbd;
1770 sprintf(disk->disk_name, "nbd%d", index);
1771 err = add_disk(disk);
1772 if (err)
1773 goto out_free_work;
1774
1775 /*
1776 * Now publish the device.
1777 */
1778 refcount_set(&nbd->refs, refs);
1779 nbd_total_devices++;
1780 return nbd;
1781
1782 out_free_work:
1783 destroy_workqueue(nbd->recv_workq);
1784 out_err_disk:
1785 blk_cleanup_disk(disk);
1786 out_free_idr:
1787 mutex_lock(&nbd_index_mutex);
1788 idr_remove(&nbd_index_idr, index);
1789 mutex_unlock(&nbd_index_mutex);
1790 out_free_tags:
1791 blk_mq_free_tag_set(&nbd->tag_set);
1792 out_free_nbd:
1793 kfree(nbd);
1794 out:
1795 return ERR_PTR(err);
1796 }
1797
nbd_find_get_unused(void)1798 static struct nbd_device *nbd_find_get_unused(void)
1799 {
1800 struct nbd_device *nbd;
1801 int id;
1802
1803 lockdep_assert_held(&nbd_index_mutex);
1804
1805 idr_for_each_entry(&nbd_index_idr, nbd, id) {
1806 if (refcount_read(&nbd->config_refs) ||
1807 test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags))
1808 continue;
1809 if (refcount_inc_not_zero(&nbd->refs))
1810 return nbd;
1811 }
1812
1813 return NULL;
1814 }
1815
1816 /* Netlink interface. */
1817 static const struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = {
1818 [NBD_ATTR_INDEX] = { .type = NLA_U32 },
1819 [NBD_ATTR_SIZE_BYTES] = { .type = NLA_U64 },
1820 [NBD_ATTR_BLOCK_SIZE_BYTES] = { .type = NLA_U64 },
1821 [NBD_ATTR_TIMEOUT] = { .type = NLA_U64 },
1822 [NBD_ATTR_SERVER_FLAGS] = { .type = NLA_U64 },
1823 [NBD_ATTR_CLIENT_FLAGS] = { .type = NLA_U64 },
1824 [NBD_ATTR_SOCKETS] = { .type = NLA_NESTED},
1825 [NBD_ATTR_DEAD_CONN_TIMEOUT] = { .type = NLA_U64 },
1826 [NBD_ATTR_DEVICE_LIST] = { .type = NLA_NESTED},
1827 [NBD_ATTR_BACKEND_IDENTIFIER] = { .type = NLA_STRING},
1828 };
1829
1830 static const struct nla_policy nbd_sock_policy[NBD_SOCK_MAX + 1] = {
1831 [NBD_SOCK_FD] = { .type = NLA_U32 },
1832 };
1833
1834 /* We don't use this right now since we don't parse the incoming list, but we
1835 * still want it here so userspace knows what to expect.
1836 */
1837 static const struct nla_policy __attribute__((unused))
1838 nbd_device_policy[NBD_DEVICE_ATTR_MAX + 1] = {
1839 [NBD_DEVICE_INDEX] = { .type = NLA_U32 },
1840 [NBD_DEVICE_CONNECTED] = { .type = NLA_U8 },
1841 };
1842
nbd_genl_size_set(struct genl_info * info,struct nbd_device * nbd)1843 static int nbd_genl_size_set(struct genl_info *info, struct nbd_device *nbd)
1844 {
1845 struct nbd_config *config = nbd->config;
1846 u64 bsize = nbd_blksize(config);
1847 u64 bytes = config->bytesize;
1848
1849 if (info->attrs[NBD_ATTR_SIZE_BYTES])
1850 bytes = nla_get_u64(info->attrs[NBD_ATTR_SIZE_BYTES]);
1851
1852 if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES])
1853 bsize = nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]);
1854
1855 if (bytes != config->bytesize || bsize != nbd_blksize(config))
1856 return nbd_set_size(nbd, bytes, bsize);
1857 return 0;
1858 }
1859
nbd_genl_connect(struct sk_buff * skb,struct genl_info * info)1860 static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
1861 {
1862 struct nbd_device *nbd;
1863 struct nbd_config *config;
1864 int index = -1;
1865 int ret;
1866 bool put_dev = false;
1867
1868 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1869 return -EPERM;
1870
1871 if (info->attrs[NBD_ATTR_INDEX]) {
1872 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1873
1874 /*
1875 * Too big first_minor can cause duplicate creation of
1876 * sysfs files/links, since index << part_shift might overflow, or
1877 * MKDEV() expect that the max bits of first_minor is 20.
1878 */
1879 if (index < 0 || index > MINORMASK >> part_shift) {
1880 printk(KERN_ERR "nbd: illegal input index %d\n", index);
1881 return -EINVAL;
1882 }
1883 }
1884 if (!info->attrs[NBD_ATTR_SOCKETS]) {
1885 printk(KERN_ERR "nbd: must specify at least one socket\n");
1886 return -EINVAL;
1887 }
1888 if (!info->attrs[NBD_ATTR_SIZE_BYTES]) {
1889 printk(KERN_ERR "nbd: must specify a size in bytes for the device\n");
1890 return -EINVAL;
1891 }
1892 again:
1893 mutex_lock(&nbd_index_mutex);
1894 if (index == -1) {
1895 nbd = nbd_find_get_unused();
1896 } else {
1897 nbd = idr_find(&nbd_index_idr, index);
1898 if (nbd) {
1899 if ((test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags) &&
1900 test_bit(NBD_DISCONNECT_REQUESTED, &nbd->flags)) ||
1901 !refcount_inc_not_zero(&nbd->refs)) {
1902 mutex_unlock(&nbd_index_mutex);
1903 pr_err("nbd: device at index %d is going down\n",
1904 index);
1905 return -EINVAL;
1906 }
1907 }
1908 }
1909 mutex_unlock(&nbd_index_mutex);
1910
1911 if (!nbd) {
1912 nbd = nbd_dev_add(index, 2);
1913 if (IS_ERR(nbd)) {
1914 pr_err("nbd: failed to add new device\n");
1915 return PTR_ERR(nbd);
1916 }
1917 }
1918
1919 mutex_lock(&nbd->config_lock);
1920 if (refcount_read(&nbd->config_refs)) {
1921 mutex_unlock(&nbd->config_lock);
1922 nbd_put(nbd);
1923 if (index == -1)
1924 goto again;
1925 printk(KERN_ERR "nbd: nbd%d already in use\n", index);
1926 return -EBUSY;
1927 }
1928 if (WARN_ON(nbd->config)) {
1929 mutex_unlock(&nbd->config_lock);
1930 nbd_put(nbd);
1931 return -EINVAL;
1932 }
1933 config = nbd_alloc_config();
1934 if (IS_ERR(config)) {
1935 mutex_unlock(&nbd->config_lock);
1936 nbd_put(nbd);
1937 printk(KERN_ERR "nbd: couldn't allocate config\n");
1938 return PTR_ERR(config);
1939 }
1940 nbd->config = config;
1941 refcount_set(&nbd->config_refs, 1);
1942 set_bit(NBD_RT_BOUND, &config->runtime_flags);
1943
1944 ret = nbd_genl_size_set(info, nbd);
1945 if (ret)
1946 goto out;
1947
1948 if (info->attrs[NBD_ATTR_TIMEOUT])
1949 nbd_set_cmd_timeout(nbd,
1950 nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]));
1951 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
1952 config->dead_conn_timeout =
1953 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
1954 config->dead_conn_timeout *= HZ;
1955 }
1956 if (info->attrs[NBD_ATTR_SERVER_FLAGS])
1957 config->flags =
1958 nla_get_u64(info->attrs[NBD_ATTR_SERVER_FLAGS]);
1959 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
1960 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
1961 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
1962 /*
1963 * We have 1 ref to keep the device around, and then 1
1964 * ref for our current operation here, which will be
1965 * inherited by the config. If we already have
1966 * DESTROY_ON_DISCONNECT set then we know we don't have
1967 * that extra ref already held so we don't need the
1968 * put_dev.
1969 */
1970 if (!test_and_set_bit(NBD_DESTROY_ON_DISCONNECT,
1971 &nbd->flags))
1972 put_dev = true;
1973 } else {
1974 if (test_and_clear_bit(NBD_DESTROY_ON_DISCONNECT,
1975 &nbd->flags))
1976 refcount_inc(&nbd->refs);
1977 }
1978 if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {
1979 set_bit(NBD_RT_DISCONNECT_ON_CLOSE,
1980 &config->runtime_flags);
1981 }
1982 }
1983
1984 if (info->attrs[NBD_ATTR_SOCKETS]) {
1985 struct nlattr *attr;
1986 int rem, fd;
1987
1988 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
1989 rem) {
1990 struct nlattr *socks[NBD_SOCK_MAX+1];
1991
1992 if (nla_type(attr) != NBD_SOCK_ITEM) {
1993 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");
1994 ret = -EINVAL;
1995 goto out;
1996 }
1997 ret = nla_parse_nested_deprecated(socks, NBD_SOCK_MAX,
1998 attr,
1999 nbd_sock_policy,
2000 info->extack);
2001 if (ret != 0) {
2002 printk(KERN_ERR "nbd: error processing sock list\n");
2003 ret = -EINVAL;
2004 goto out;
2005 }
2006 if (!socks[NBD_SOCK_FD])
2007 continue;
2008 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
2009 ret = nbd_add_socket(nbd, fd, true);
2010 if (ret)
2011 goto out;
2012 }
2013 }
2014 ret = nbd_start_device(nbd);
2015 if (ret)
2016 goto out;
2017 if (info->attrs[NBD_ATTR_BACKEND_IDENTIFIER]) {
2018 nbd->backend = nla_strdup(info->attrs[NBD_ATTR_BACKEND_IDENTIFIER],
2019 GFP_KERNEL);
2020 if (!nbd->backend) {
2021 ret = -ENOMEM;
2022 goto out;
2023 }
2024 }
2025 ret = device_create_file(disk_to_dev(nbd->disk), &backend_attr);
2026 if (ret) {
2027 dev_err(disk_to_dev(nbd->disk),
2028 "device_create_file failed for backend!\n");
2029 goto out;
2030 }
2031 set_bit(NBD_RT_HAS_BACKEND_FILE, &config->runtime_flags);
2032 out:
2033 mutex_unlock(&nbd->config_lock);
2034 if (!ret) {
2035 set_bit(NBD_RT_HAS_CONFIG_REF, &config->runtime_flags);
2036 refcount_inc(&nbd->config_refs);
2037 nbd_connect_reply(info, nbd->index);
2038 }
2039 nbd_config_put(nbd);
2040 if (put_dev)
2041 nbd_put(nbd);
2042 return ret;
2043 }
2044
nbd_disconnect_and_put(struct nbd_device * nbd)2045 static void nbd_disconnect_and_put(struct nbd_device *nbd)
2046 {
2047 mutex_lock(&nbd->config_lock);
2048 nbd_disconnect(nbd);
2049 sock_shutdown(nbd);
2050 wake_up(&nbd->config->conn_wait);
2051 /*
2052 * Make sure recv thread has finished, we can safely call nbd_clear_que()
2053 * to cancel the inflight I/Os.
2054 */
2055 flush_workqueue(nbd->recv_workq);
2056 nbd_clear_que(nbd);
2057 nbd->task_setup = NULL;
2058 mutex_unlock(&nbd->config_lock);
2059
2060 if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF,
2061 &nbd->config->runtime_flags))
2062 nbd_config_put(nbd);
2063 }
2064
nbd_genl_disconnect(struct sk_buff * skb,struct genl_info * info)2065 static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info)
2066 {
2067 struct nbd_device *nbd;
2068 int index;
2069
2070 if (!netlink_capable(skb, CAP_SYS_ADMIN))
2071 return -EPERM;
2072
2073 if (!info->attrs[NBD_ATTR_INDEX]) {
2074 printk(KERN_ERR "nbd: must specify an index to disconnect\n");
2075 return -EINVAL;
2076 }
2077 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2078 mutex_lock(&nbd_index_mutex);
2079 nbd = idr_find(&nbd_index_idr, index);
2080 if (!nbd) {
2081 mutex_unlock(&nbd_index_mutex);
2082 printk(KERN_ERR "nbd: couldn't find device at index %d\n",
2083 index);
2084 return -EINVAL;
2085 }
2086 if (!refcount_inc_not_zero(&nbd->refs)) {
2087 mutex_unlock(&nbd_index_mutex);
2088 printk(KERN_ERR "nbd: device at index %d is going down\n",
2089 index);
2090 return -EINVAL;
2091 }
2092 mutex_unlock(&nbd_index_mutex);
2093 if (!refcount_inc_not_zero(&nbd->config_refs))
2094 goto put_nbd;
2095 nbd_disconnect_and_put(nbd);
2096 nbd_config_put(nbd);
2097 put_nbd:
2098 nbd_put(nbd);
2099 return 0;
2100 }
2101
nbd_genl_reconfigure(struct sk_buff * skb,struct genl_info * info)2102 static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info)
2103 {
2104 struct nbd_device *nbd = NULL;
2105 struct nbd_config *config;
2106 int index;
2107 int ret = 0;
2108 bool put_dev = false;
2109
2110 if (!netlink_capable(skb, CAP_SYS_ADMIN))
2111 return -EPERM;
2112
2113 if (!info->attrs[NBD_ATTR_INDEX]) {
2114 printk(KERN_ERR "nbd: must specify a device to reconfigure\n");
2115 return -EINVAL;
2116 }
2117 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2118 mutex_lock(&nbd_index_mutex);
2119 nbd = idr_find(&nbd_index_idr, index);
2120 if (!nbd) {
2121 mutex_unlock(&nbd_index_mutex);
2122 printk(KERN_ERR "nbd: couldn't find a device at index %d\n",
2123 index);
2124 return -EINVAL;
2125 }
2126 if (nbd->backend) {
2127 if (info->attrs[NBD_ATTR_BACKEND_IDENTIFIER]) {
2128 if (nla_strcmp(info->attrs[NBD_ATTR_BACKEND_IDENTIFIER],
2129 nbd->backend)) {
2130 mutex_unlock(&nbd_index_mutex);
2131 dev_err(nbd_to_dev(nbd),
2132 "backend image doesn't match with %s\n",
2133 nbd->backend);
2134 return -EINVAL;
2135 }
2136 } else {
2137 mutex_unlock(&nbd_index_mutex);
2138 dev_err(nbd_to_dev(nbd), "must specify backend\n");
2139 return -EINVAL;
2140 }
2141 }
2142 if (!refcount_inc_not_zero(&nbd->refs)) {
2143 mutex_unlock(&nbd_index_mutex);
2144 printk(KERN_ERR "nbd: device at index %d is going down\n",
2145 index);
2146 return -EINVAL;
2147 }
2148 mutex_unlock(&nbd_index_mutex);
2149
2150 if (!refcount_inc_not_zero(&nbd->config_refs)) {
2151 dev_err(nbd_to_dev(nbd),
2152 "not configured, cannot reconfigure\n");
2153 nbd_put(nbd);
2154 return -EINVAL;
2155 }
2156
2157 mutex_lock(&nbd->config_lock);
2158 config = nbd->config;
2159 if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) ||
2160 !nbd->pid) {
2161 dev_err(nbd_to_dev(nbd),
2162 "not configured, cannot reconfigure\n");
2163 ret = -EINVAL;
2164 goto out;
2165 }
2166
2167 ret = nbd_genl_size_set(info, nbd);
2168 if (ret)
2169 goto out;
2170
2171 if (info->attrs[NBD_ATTR_TIMEOUT])
2172 nbd_set_cmd_timeout(nbd,
2173 nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]));
2174 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
2175 config->dead_conn_timeout =
2176 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
2177 config->dead_conn_timeout *= HZ;
2178 }
2179 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
2180 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
2181 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
2182 if (!test_and_set_bit(NBD_DESTROY_ON_DISCONNECT,
2183 &nbd->flags))
2184 put_dev = true;
2185 } else {
2186 if (test_and_clear_bit(NBD_DESTROY_ON_DISCONNECT,
2187 &nbd->flags))
2188 refcount_inc(&nbd->refs);
2189 }
2190
2191 if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {
2192 set_bit(NBD_RT_DISCONNECT_ON_CLOSE,
2193 &config->runtime_flags);
2194 } else {
2195 clear_bit(NBD_RT_DISCONNECT_ON_CLOSE,
2196 &config->runtime_flags);
2197 }
2198 }
2199
2200 if (info->attrs[NBD_ATTR_SOCKETS]) {
2201 struct nlattr *attr;
2202 int rem, fd;
2203
2204 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
2205 rem) {
2206 struct nlattr *socks[NBD_SOCK_MAX+1];
2207
2208 if (nla_type(attr) != NBD_SOCK_ITEM) {
2209 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");
2210 ret = -EINVAL;
2211 goto out;
2212 }
2213 ret = nla_parse_nested_deprecated(socks, NBD_SOCK_MAX,
2214 attr,
2215 nbd_sock_policy,
2216 info->extack);
2217 if (ret != 0) {
2218 printk(KERN_ERR "nbd: error processing sock list\n");
2219 ret = -EINVAL;
2220 goto out;
2221 }
2222 if (!socks[NBD_SOCK_FD])
2223 continue;
2224 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
2225 ret = nbd_reconnect_socket(nbd, fd);
2226 if (ret) {
2227 if (ret == -ENOSPC)
2228 ret = 0;
2229 goto out;
2230 }
2231 dev_info(nbd_to_dev(nbd), "reconnected socket\n");
2232 }
2233 }
2234 out:
2235 mutex_unlock(&nbd->config_lock);
2236 nbd_config_put(nbd);
2237 nbd_put(nbd);
2238 if (put_dev)
2239 nbd_put(nbd);
2240 return ret;
2241 }
2242
2243 static const struct genl_small_ops nbd_connect_genl_ops[] = {
2244 {
2245 .cmd = NBD_CMD_CONNECT,
2246 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2247 .doit = nbd_genl_connect,
2248 },
2249 {
2250 .cmd = NBD_CMD_DISCONNECT,
2251 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2252 .doit = nbd_genl_disconnect,
2253 },
2254 {
2255 .cmd = NBD_CMD_RECONFIGURE,
2256 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2257 .doit = nbd_genl_reconfigure,
2258 },
2259 {
2260 .cmd = NBD_CMD_STATUS,
2261 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2262 .doit = nbd_genl_status,
2263 },
2264 };
2265
2266 static const struct genl_multicast_group nbd_mcast_grps[] = {
2267 { .name = NBD_GENL_MCAST_GROUP_NAME, },
2268 };
2269
2270 static struct genl_family nbd_genl_family __ro_after_init = {
2271 .hdrsize = 0,
2272 .name = NBD_GENL_FAMILY_NAME,
2273 .version = NBD_GENL_VERSION,
2274 .module = THIS_MODULE,
2275 .small_ops = nbd_connect_genl_ops,
2276 .n_small_ops = ARRAY_SIZE(nbd_connect_genl_ops),
2277 .maxattr = NBD_ATTR_MAX,
2278 .policy = nbd_attr_policy,
2279 .mcgrps = nbd_mcast_grps,
2280 .n_mcgrps = ARRAY_SIZE(nbd_mcast_grps),
2281 };
2282
populate_nbd_status(struct nbd_device * nbd,struct sk_buff * reply)2283 static int populate_nbd_status(struct nbd_device *nbd, struct sk_buff *reply)
2284 {
2285 struct nlattr *dev_opt;
2286 u8 connected = 0;
2287 int ret;
2288
2289 /* This is a little racey, but for status it's ok. The
2290 * reason we don't take a ref here is because we can't
2291 * take a ref in the index == -1 case as we would need
2292 * to put under the nbd_index_mutex, which could
2293 * deadlock if we are configured to remove ourselves
2294 * once we're disconnected.
2295 */
2296 if (refcount_read(&nbd->config_refs))
2297 connected = 1;
2298 dev_opt = nla_nest_start_noflag(reply, NBD_DEVICE_ITEM);
2299 if (!dev_opt)
2300 return -EMSGSIZE;
2301 ret = nla_put_u32(reply, NBD_DEVICE_INDEX, nbd->index);
2302 if (ret)
2303 return -EMSGSIZE;
2304 ret = nla_put_u8(reply, NBD_DEVICE_CONNECTED,
2305 connected);
2306 if (ret)
2307 return -EMSGSIZE;
2308 nla_nest_end(reply, dev_opt);
2309 return 0;
2310 }
2311
status_cb(int id,void * ptr,void * data)2312 static int status_cb(int id, void *ptr, void *data)
2313 {
2314 struct nbd_device *nbd = ptr;
2315 return populate_nbd_status(nbd, (struct sk_buff *)data);
2316 }
2317
nbd_genl_status(struct sk_buff * skb,struct genl_info * info)2318 static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info)
2319 {
2320 struct nlattr *dev_list;
2321 struct sk_buff *reply;
2322 void *reply_head;
2323 size_t msg_size;
2324 int index = -1;
2325 int ret = -ENOMEM;
2326
2327 if (info->attrs[NBD_ATTR_INDEX])
2328 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2329
2330 mutex_lock(&nbd_index_mutex);
2331
2332 msg_size = nla_total_size(nla_attr_size(sizeof(u32)) +
2333 nla_attr_size(sizeof(u8)));
2334 msg_size *= (index == -1) ? nbd_total_devices : 1;
2335
2336 reply = genlmsg_new(msg_size, GFP_KERNEL);
2337 if (!reply)
2338 goto out;
2339 reply_head = genlmsg_put_reply(reply, info, &nbd_genl_family, 0,
2340 NBD_CMD_STATUS);
2341 if (!reply_head) {
2342 nlmsg_free(reply);
2343 goto out;
2344 }
2345
2346 dev_list = nla_nest_start_noflag(reply, NBD_ATTR_DEVICE_LIST);
2347 if (index == -1) {
2348 ret = idr_for_each(&nbd_index_idr, &status_cb, reply);
2349 if (ret) {
2350 nlmsg_free(reply);
2351 goto out;
2352 }
2353 } else {
2354 struct nbd_device *nbd;
2355 nbd = idr_find(&nbd_index_idr, index);
2356 if (nbd) {
2357 ret = populate_nbd_status(nbd, reply);
2358 if (ret) {
2359 nlmsg_free(reply);
2360 goto out;
2361 }
2362 }
2363 }
2364 nla_nest_end(reply, dev_list);
2365 genlmsg_end(reply, reply_head);
2366 ret = genlmsg_reply(reply, info);
2367 out:
2368 mutex_unlock(&nbd_index_mutex);
2369 return ret;
2370 }
2371
nbd_connect_reply(struct genl_info * info,int index)2372 static void nbd_connect_reply(struct genl_info *info, int index)
2373 {
2374 struct sk_buff *skb;
2375 void *msg_head;
2376 int ret;
2377
2378 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2379 if (!skb)
2380 return;
2381 msg_head = genlmsg_put_reply(skb, info, &nbd_genl_family, 0,
2382 NBD_CMD_CONNECT);
2383 if (!msg_head) {
2384 nlmsg_free(skb);
2385 return;
2386 }
2387 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2388 if (ret) {
2389 nlmsg_free(skb);
2390 return;
2391 }
2392 genlmsg_end(skb, msg_head);
2393 genlmsg_reply(skb, info);
2394 }
2395
nbd_mcast_index(int index)2396 static void nbd_mcast_index(int index)
2397 {
2398 struct sk_buff *skb;
2399 void *msg_head;
2400 int ret;
2401
2402 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2403 if (!skb)
2404 return;
2405 msg_head = genlmsg_put(skb, 0, 0, &nbd_genl_family, 0,
2406 NBD_CMD_LINK_DEAD);
2407 if (!msg_head) {
2408 nlmsg_free(skb);
2409 return;
2410 }
2411 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2412 if (ret) {
2413 nlmsg_free(skb);
2414 return;
2415 }
2416 genlmsg_end(skb, msg_head);
2417 genlmsg_multicast(&nbd_genl_family, skb, 0, 0, GFP_KERNEL);
2418 }
2419
nbd_dead_link_work(struct work_struct * work)2420 static void nbd_dead_link_work(struct work_struct *work)
2421 {
2422 struct link_dead_args *args = container_of(work, struct link_dead_args,
2423 work);
2424 nbd_mcast_index(args->index);
2425 kfree(args);
2426 }
2427
nbd_init(void)2428 static int __init nbd_init(void)
2429 {
2430 int i;
2431
2432 BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
2433
2434 if (max_part < 0) {
2435 printk(KERN_ERR "nbd: max_part must be >= 0\n");
2436 return -EINVAL;
2437 }
2438
2439 part_shift = 0;
2440 if (max_part > 0) {
2441 part_shift = fls(max_part);
2442
2443 /*
2444 * Adjust max_part according to part_shift as it is exported
2445 * to user space so that user can know the max number of
2446 * partition kernel should be able to manage.
2447 *
2448 * Note that -1 is required because partition 0 is reserved
2449 * for the whole disk.
2450 */
2451 max_part = (1UL << part_shift) - 1;
2452 }
2453
2454 if ((1UL << part_shift) > DISK_MAX_PARTS)
2455 return -EINVAL;
2456
2457 if (nbds_max > 1UL << (MINORBITS - part_shift))
2458 return -EINVAL;
2459
2460 if (register_blkdev(NBD_MAJOR, "nbd"))
2461 return -EIO;
2462
2463 nbd_del_wq = alloc_workqueue("nbd-del", WQ_UNBOUND, 0);
2464 if (!nbd_del_wq) {
2465 unregister_blkdev(NBD_MAJOR, "nbd");
2466 return -ENOMEM;
2467 }
2468
2469 if (genl_register_family(&nbd_genl_family)) {
2470 destroy_workqueue(nbd_del_wq);
2471 unregister_blkdev(NBD_MAJOR, "nbd");
2472 return -EINVAL;
2473 }
2474 nbd_dbg_init();
2475
2476 for (i = 0; i < nbds_max; i++)
2477 nbd_dev_add(i, 1);
2478 return 0;
2479 }
2480
nbd_exit_cb(int id,void * ptr,void * data)2481 static int nbd_exit_cb(int id, void *ptr, void *data)
2482 {
2483 struct list_head *list = (struct list_head *)data;
2484 struct nbd_device *nbd = ptr;
2485
2486 /* Skip nbd that is being removed asynchronously */
2487 if (refcount_read(&nbd->refs))
2488 list_add_tail(&nbd->list, list);
2489
2490 return 0;
2491 }
2492
nbd_cleanup(void)2493 static void __exit nbd_cleanup(void)
2494 {
2495 struct nbd_device *nbd;
2496 LIST_HEAD(del_list);
2497
2498 /*
2499 * Unregister netlink interface prior to waiting
2500 * for the completion of netlink commands.
2501 */
2502 genl_unregister_family(&nbd_genl_family);
2503
2504 nbd_dbg_close();
2505
2506 mutex_lock(&nbd_index_mutex);
2507 idr_for_each(&nbd_index_idr, &nbd_exit_cb, &del_list);
2508 mutex_unlock(&nbd_index_mutex);
2509
2510 while (!list_empty(&del_list)) {
2511 nbd = list_first_entry(&del_list, struct nbd_device, list);
2512 list_del_init(&nbd->list);
2513 if (refcount_read(&nbd->config_refs))
2514 printk(KERN_ERR "nbd: possibly leaking nbd_config (ref %d)\n",
2515 refcount_read(&nbd->config_refs));
2516 if (refcount_read(&nbd->refs) != 1)
2517 printk(KERN_ERR "nbd: possibly leaking a device\n");
2518 nbd_put(nbd);
2519 }
2520
2521 /* Also wait for nbd_dev_remove_work() completes */
2522 destroy_workqueue(nbd_del_wq);
2523
2524 idr_destroy(&nbd_index_idr);
2525 unregister_blkdev(NBD_MAJOR, "nbd");
2526 }
2527
2528 module_init(nbd_init);
2529 module_exit(nbd_cleanup);
2530
2531 MODULE_DESCRIPTION("Network Block Device");
2532 MODULE_LICENSE("GPL");
2533
2534 module_param(nbds_max, int, 0444);
2535 MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
2536 module_param(max_part, int, 0444);
2537 MODULE_PARM_DESC(max_part, "number of partitions per device (default: 16)");
2538