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1/*
2 * Network block device - make block devices work over TCP
3 *
4 * Note that you can not swap over this thing, yet. Seems to work but
5 * deadlocks sometimes - you can not swap over TCP in general.
6 *
7 * Copyright 1997-2000, 2008 Pavel Machek <pavel@ucw.cz>
8 * Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com>
9 *
10 * This file is released under GPLv2 or later.
11 *
12 * (part of code stolen from loop.c)
13 */
14
15#include <linux/major.h>
16
17#include <linux/blkdev.h>
18#include <linux/module.h>
19#include <linux/init.h>
20#include <linux/sched.h>
21#include <linux/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/err.h>
30#include <linux/kernel.h>
31#include <linux/slab.h>
32#include <net/sock.h>
33#include <linux/net.h>
34#include <linux/kthread.h>
35
36#include <asm/uaccess.h>
37#include <asm/system.h>
38#include <asm/types.h>
39
40#include <linux/nbd.h>
41
42#define LO_MAGIC 0x68797548
43
44#ifdef NDEBUG
45#define dprintk(flags, fmt...)
46#else /* NDEBUG */
47#define dprintk(flags, fmt...) do { \
48 if (debugflags & (flags)) printk(KERN_DEBUG fmt); \
49} while (0)
50#define DBG_IOCTL 0x0004
51#define DBG_INIT 0x0010
52#define DBG_EXIT 0x0020
53#define DBG_BLKDEV 0x0100
54#define DBG_RX 0x0200
55#define DBG_TX 0x0400
56static unsigned int debugflags;
57#endif /* NDEBUG */
58
59static unsigned int nbds_max = 16;
60static struct nbd_device *nbd_dev;
61static int max_part;
62
63/*
64 * Use just one lock (or at most 1 per NIC). Two arguments for this:
65 * 1. Each NIC is essentially a synchronization point for all servers
66 * accessed through that NIC so there's no need to have more locks
67 * than NICs anyway.
68 * 2. More locks lead to more "Dirty cache line bouncing" which will slow
69 * down each lock to the point where they're actually slower than just
70 * a single lock.
71 * Thanks go to Jens Axboe and Al Viro for their LKML emails explaining this!
72 */
73static DEFINE_SPINLOCK(nbd_lock);
74
75#ifndef NDEBUG
76static const char *ioctl_cmd_to_ascii(int cmd)
77{
78 switch (cmd) {
79 case NBD_SET_SOCK: return "set-sock";
80 case NBD_SET_BLKSIZE: return "set-blksize";
81 case NBD_SET_SIZE: return "set-size";
82 case NBD_DO_IT: return "do-it";
83 case NBD_CLEAR_SOCK: return "clear-sock";
84 case NBD_CLEAR_QUE: return "clear-que";
85 case NBD_PRINT_DEBUG: return "print-debug";
86 case NBD_SET_SIZE_BLOCKS: return "set-size-blocks";
87 case NBD_DISCONNECT: return "disconnect";
88 case BLKROSET: return "set-read-only";
89 case BLKFLSBUF: return "flush-buffer-cache";
90 }
91 return "unknown";
92}
93
94static const char *nbdcmd_to_ascii(int cmd)
95{
96 switch (cmd) {
97 case NBD_CMD_READ: return "read";
98 case NBD_CMD_WRITE: return "write";
99 case NBD_CMD_DISC: return "disconnect";
100 }
101 return "invalid";
102}
103#endif /* NDEBUG */
104
105static void nbd_end_request(struct request *req)
106{
107 int error = req->errors ? -EIO : 0;
108 struct request_queue *q = req->q;
109 unsigned long flags;
110
111 dprintk(DBG_BLKDEV, "%s: request %p: %s\n", req->rq_disk->disk_name,
112 req, error ? "failed" : "done");
113
114 spin_lock_irqsave(q->queue_lock, flags);
115 __blk_end_request_all(req, error);
116 spin_unlock_irqrestore(q->queue_lock, flags);
117}
118
119static void sock_shutdown(struct nbd_device *lo, int lock)
120{
121 /* Forcibly shutdown the socket causing all listeners
122 * to error
123 *
124 * FIXME: This code is duplicated from sys_shutdown, but
125 * there should be a more generic interface rather than
126 * calling socket ops directly here */
127 if (lock)
128 mutex_lock(&lo->tx_lock);
129 if (lo->sock) {
130 printk(KERN_WARNING "%s: shutting down socket\n",
131 lo->disk->disk_name);
132 kernel_sock_shutdown(lo->sock, SHUT_RDWR);
133 lo->sock = NULL;
134 }
135 if (lock)
136 mutex_unlock(&lo->tx_lock);
137}
138
139static void nbd_xmit_timeout(unsigned long arg)
140{
141 struct task_struct *task = (struct task_struct *)arg;
142
143 printk(KERN_WARNING "nbd: killing hung xmit (%s, pid: %d)\n",
144 task->comm, task->pid);
145 force_sig(SIGKILL, task);
146}
147
148/*
149 * Send or receive packet.
150 */
151static int sock_xmit(struct nbd_device *lo, int send, void *buf, int size,
152 int msg_flags)
153{
154 struct socket *sock = lo->sock;
155 int result;
156 struct msghdr msg;
157 struct kvec iov;
158 sigset_t blocked, oldset;
159
160 if (unlikely(!sock)) {
161 printk(KERN_ERR "%s: Attempted %s on closed socket in sock_xmit\n",
162 lo->disk->disk_name, (send ? "send" : "recv"));
163 return -EINVAL;
164 }
165
166 /* Allow interception of SIGKILL only
167 * Don't allow other signals to interrupt the transmission */
168 siginitsetinv(&blocked, sigmask(SIGKILL));
169 sigprocmask(SIG_SETMASK, &blocked, &oldset);
170
171 do {
172 sock->sk->sk_allocation = GFP_NOIO;
173 iov.iov_base = buf;
174 iov.iov_len = size;
175 msg.msg_name = NULL;
176 msg.msg_namelen = 0;
177 msg.msg_control = NULL;
178 msg.msg_controllen = 0;
179 msg.msg_flags = msg_flags | MSG_NOSIGNAL;
180
181 if (send) {
182 struct timer_list ti;
183
184 if (lo->xmit_timeout) {
185 init_timer(&ti);
186 ti.function = nbd_xmit_timeout;
187 ti.data = (unsigned long)current;
188 ti.expires = jiffies + lo->xmit_timeout;
189 add_timer(&ti);
190 }
191 result = kernel_sendmsg(sock, &msg, &iov, 1, size);
192 if (lo->xmit_timeout)
193 del_timer_sync(&ti);
194 } else
195 result = kernel_recvmsg(sock, &msg, &iov, 1, size,
196 msg.msg_flags);
197
198 if (signal_pending(current)) {
199 siginfo_t info;
200 printk(KERN_WARNING "nbd (pid %d: %s) got signal %d\n",
201 task_pid_nr(current), current->comm,
202 dequeue_signal_lock(current, ¤t->blocked, &info));
203 result = -EINTR;
204 sock_shutdown(lo, !send);
205 break;
206 }
207
208 if (result <= 0) {
209 if (result == 0)
210 result = -EPIPE; /* short read */
211 break;
212 }
213 size -= result;
214 buf += result;
215 } while (size > 0);
216
217 sigprocmask(SIG_SETMASK, &oldset, NULL);
218
219 return result;
220}
221
222static inline int sock_send_bvec(struct nbd_device *lo, struct bio_vec *bvec,
223 int flags)
224{
225 int result;
226 void *kaddr = kmap(bvec->bv_page);
227 result = sock_xmit(lo, 1, kaddr + bvec->bv_offset, bvec->bv_len, flags);
228 kunmap(bvec->bv_page);
229 return result;
230}
231
232/* always call with the tx_lock held */
233static int nbd_send_req(struct nbd_device *lo, struct request *req)
234{
235 int result, flags;
236 struct nbd_request request;
237 unsigned long size = blk_rq_bytes(req);
238
239 request.magic = htonl(NBD_REQUEST_MAGIC);
240 request.type = htonl(nbd_cmd(req));
241 request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
242 request.len = htonl(size);
243 memcpy(request.handle, &req, sizeof(req));
244
245 dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%uB)\n",
246 lo->disk->disk_name, req,
247 nbdcmd_to_ascii(nbd_cmd(req)),
248 (unsigned long long)blk_rq_pos(req) << 9,
249 blk_rq_bytes(req));
250 result = sock_xmit(lo, 1, &request, sizeof(request),
251 (nbd_cmd(req) == NBD_CMD_WRITE) ? MSG_MORE : 0);
252 if (result <= 0) {
253 printk(KERN_ERR "%s: Send control failed (result %d)\n",
254 lo->disk->disk_name, result);
255 goto error_out;
256 }
257
258 if (nbd_cmd(req) == NBD_CMD_WRITE) {
259 struct req_iterator iter;
260 struct bio_vec *bvec;
261 /*
262 * we are really probing at internals to determine
263 * whether to set MSG_MORE or not...
264 */
265 rq_for_each_segment(bvec, req, iter) {
266 flags = 0;
267 if (!rq_iter_last(req, iter))
268 flags = MSG_MORE;
269 dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n",
270 lo->disk->disk_name, req, bvec->bv_len);
271 result = sock_send_bvec(lo, bvec, flags);
272 if (result <= 0) {
273 printk(KERN_ERR "%s: Send data failed (result %d)\n",
274 lo->disk->disk_name, result);
275 goto error_out;
276 }
277 }
278 }
279 return 0;
280
281error_out:
282 return -EIO;
283}
284
285static struct request *nbd_find_request(struct nbd_device *lo,
286 struct request *xreq)
287{
288 struct request *req, *tmp;
289 int err;
290
291 err = wait_event_interruptible(lo->active_wq, lo->active_req != xreq);
292 if (unlikely(err))
293 goto out;
294
295 spin_lock(&lo->queue_lock);
296 list_for_each_entry_safe(req, tmp, &lo->queue_head, queuelist) {
297 if (req != xreq)
298 continue;
299 list_del_init(&req->queuelist);
300 spin_unlock(&lo->queue_lock);
301 return req;
302 }
303 spin_unlock(&lo->queue_lock);
304
305 err = -ENOENT;
306
307out:
308 return ERR_PTR(err);
309}
310
311static inline int sock_recv_bvec(struct nbd_device *lo, struct bio_vec *bvec)
312{
313 int result;
314 void *kaddr = kmap(bvec->bv_page);
315 result = sock_xmit(lo, 0, kaddr + bvec->bv_offset, bvec->bv_len,
316 MSG_WAITALL);
317 kunmap(bvec->bv_page);
318 return result;
319}
320
321/* NULL returned = something went wrong, inform userspace */
322static struct request *nbd_read_stat(struct nbd_device *lo)
323{
324 int result;
325 struct nbd_reply reply;
326 struct request *req;
327
328 reply.magic = 0;
329 result = sock_xmit(lo, 0, &reply, sizeof(reply), MSG_WAITALL);
330 if (result <= 0) {
331 printk(KERN_ERR "%s: Receive control failed (result %d)\n",
332 lo->disk->disk_name, result);
333 goto harderror;
334 }
335
336 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) {
337 printk(KERN_ERR "%s: Wrong magic (0x%lx)\n",
338 lo->disk->disk_name,
339 (unsigned long)ntohl(reply.magic));
340 result = -EPROTO;
341 goto harderror;
342 }
343
344 req = nbd_find_request(lo, *(struct request **)reply.handle);
345 if (IS_ERR(req)) {
346 result = PTR_ERR(req);
347 if (result != -ENOENT)
348 goto harderror;
349
350 printk(KERN_ERR "%s: Unexpected reply (%p)\n",
351 lo->disk->disk_name, reply.handle);
352 result = -EBADR;
353 goto harderror;
354 }
355
356 if (ntohl(reply.error)) {
357 printk(KERN_ERR "%s: Other side returned error (%d)\n",
358 lo->disk->disk_name, ntohl(reply.error));
359 req->errors++;
360 return req;
361 }
362
363 dprintk(DBG_RX, "%s: request %p: got reply\n",
364 lo->disk->disk_name, req);
365 if (nbd_cmd(req) == NBD_CMD_READ) {
366 struct req_iterator iter;
367 struct bio_vec *bvec;
368
369 rq_for_each_segment(bvec, req, iter) {
370 result = sock_recv_bvec(lo, bvec);
371 if (result <= 0) {
372 printk(KERN_ERR "%s: Receive data failed (result %d)\n",
373 lo->disk->disk_name, result);
374 req->errors++;
375 return req;
376 }
377 dprintk(DBG_RX, "%s: request %p: got %d bytes data\n",
378 lo->disk->disk_name, req, bvec->bv_len);
379 }
380 }
381 return req;
382harderror:
383 lo->harderror = result;
384 return NULL;
385}
386
387static ssize_t pid_show(struct device *dev,
388 struct device_attribute *attr, char *buf)
389{
390 struct gendisk *disk = dev_to_disk(dev);
391
392 return sprintf(buf, "%ld\n",
393 (long) ((struct nbd_device *)disk->private_data)->pid);
394}
395
396static struct device_attribute pid_attr = {
397 .attr = { .name = "pid", .mode = S_IRUGO},
398 .show = pid_show,
399};
400
401static int nbd_do_it(struct nbd_device *lo)
402{
403 struct request *req;
404 int ret;
405
406 BUG_ON(lo->magic != LO_MAGIC);
407
408 lo->pid = current->pid;
409 ret = sysfs_create_file(&disk_to_dev(lo->disk)->kobj, &pid_attr.attr);
410 if (ret) {
411 printk(KERN_ERR "nbd: sysfs_create_file failed!");
412 lo->pid = 0;
413 return ret;
414 }
415
416 while ((req = nbd_read_stat(lo)) != NULL)
417 nbd_end_request(req);
418
419 sysfs_remove_file(&disk_to_dev(lo->disk)->kobj, &pid_attr.attr);
420 lo->pid = 0;
421 return 0;
422}
423
424static void nbd_clear_que(struct nbd_device *lo)
425{
426 struct request *req;
427
428 BUG_ON(lo->magic != LO_MAGIC);
429
430 /*
431 * Because we have set lo->sock to NULL under the tx_lock, all
432 * modifications to the list must have completed by now. For
433 * the same reason, the active_req must be NULL.
434 *
435 * As a consequence, we don't need to take the spin lock while
436 * purging the list here.
437 */
438 BUG_ON(lo->sock);
439 BUG_ON(lo->active_req);
440
441 while (!list_empty(&lo->queue_head)) {
442 req = list_entry(lo->queue_head.next, struct request,
443 queuelist);
444 list_del_init(&req->queuelist);
445 req->errors++;
446 nbd_end_request(req);
447 }
448}
449
450
451static void nbd_handle_req(struct nbd_device *lo, struct request *req)
452{
453 if (req->cmd_type != REQ_TYPE_FS)
454 goto error_out;
455
456 nbd_cmd(req) = NBD_CMD_READ;
457 if (rq_data_dir(req) == WRITE) {
458 nbd_cmd(req) = NBD_CMD_WRITE;
459 if (lo->flags & NBD_READ_ONLY) {
460 printk(KERN_ERR "%s: Write on read-only\n",
461 lo->disk->disk_name);
462 goto error_out;
463 }
464 }
465
466 req->errors = 0;
467
468 mutex_lock(&lo->tx_lock);
469 if (unlikely(!lo->sock)) {
470 mutex_unlock(&lo->tx_lock);
471 printk(KERN_ERR "%s: Attempted send on closed socket\n",
472 lo->disk->disk_name);
473 goto error_out;
474 }
475
476 lo->active_req = req;
477
478 if (nbd_send_req(lo, req) != 0) {
479 printk(KERN_ERR "%s: Request send failed\n",
480 lo->disk->disk_name);
481 req->errors++;
482 nbd_end_request(req);
483 } else {
484 spin_lock(&lo->queue_lock);
485 list_add(&req->queuelist, &lo->queue_head);
486 spin_unlock(&lo->queue_lock);
487 }
488
489 lo->active_req = NULL;
490 mutex_unlock(&lo->tx_lock);
491 wake_up_all(&lo->active_wq);
492
493 return;
494
495error_out:
496 req->errors++;
497 nbd_end_request(req);
498}
499
500static int nbd_thread(void *data)
501{
502 struct nbd_device *lo = data;
503 struct request *req;
504
505 set_user_nice(current, -20);
506 while (!kthread_should_stop() || !list_empty(&lo->waiting_queue)) {
507 /* wait for something to do */
508 wait_event_interruptible(lo->waiting_wq,
509 kthread_should_stop() ||
510 !list_empty(&lo->waiting_queue));
511
512 /* extract request */
513 if (list_empty(&lo->waiting_queue))
514 continue;
515
516 spin_lock_irq(&lo->queue_lock);
517 req = list_entry(lo->waiting_queue.next, struct request,
518 queuelist);
519 list_del_init(&req->queuelist);
520 spin_unlock_irq(&lo->queue_lock);
521
522 /* handle request */
523 nbd_handle_req(lo, req);
524 }
525 return 0;
526}
527
528/*
529 * We always wait for result of write, for now. It would be nice to make it optional
530 * in future
531 * if ((rq_data_dir(req) == WRITE) && (lo->flags & NBD_WRITE_NOCHK))
532 * { printk( "Warning: Ignoring result!\n"); nbd_end_request( req ); }
533 */
534
535static void do_nbd_request(struct request_queue *q)
536{
537 struct request *req;
538
539 while ((req = blk_fetch_request(q)) != NULL) {
540 struct nbd_device *lo;
541
542 spin_unlock_irq(q->queue_lock);
543
544 dprintk(DBG_BLKDEV, "%s: request %p: dequeued (flags=%x)\n",
545 req->rq_disk->disk_name, req, req->cmd_type);
546
547 lo = req->rq_disk->private_data;
548
549 BUG_ON(lo->magic != LO_MAGIC);
550
551 if (unlikely(!lo->sock)) {
552 printk(KERN_ERR "%s: Attempted send on closed socket\n",
553 lo->disk->disk_name);
554 req->errors++;
555 nbd_end_request(req);
556 spin_lock_irq(q->queue_lock);
557 continue;
558 }
559
560 spin_lock_irq(&lo->queue_lock);
561 list_add_tail(&req->queuelist, &lo->waiting_queue);
562 spin_unlock_irq(&lo->queue_lock);
563
564 wake_up(&lo->waiting_wq);
565
566 spin_lock_irq(q->queue_lock);
567 }
568}
569
570/* Must be called with tx_lock held */
571
572static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *lo,
573 unsigned int cmd, unsigned long arg)
574{
575 switch (cmd) {
576 case NBD_DISCONNECT: {
577 struct request sreq;
578
579 printk(KERN_INFO "%s: NBD_DISCONNECT\n", lo->disk->disk_name);
580
581 blk_rq_init(NULL, &sreq);
582 sreq.cmd_type = REQ_TYPE_SPECIAL;
583 nbd_cmd(&sreq) = NBD_CMD_DISC;
584 if (!lo->sock)
585 return -EINVAL;
586 nbd_send_req(lo, &sreq);
587 return 0;
588 }
589
590 case NBD_CLEAR_SOCK: {
591 struct file *file;
592
593 lo->sock = NULL;
594 file = lo->file;
595 lo->file = NULL;
596 nbd_clear_que(lo);
597 BUG_ON(!list_empty(&lo->queue_head));
598 if (file)
599 fput(file);
600 return 0;
601 }
602
603 case NBD_SET_SOCK: {
604 struct file *file;
605 if (lo->file)
606 return -EBUSY;
607 file = fget(arg);
608 if (file) {
609 struct inode *inode = file->f_path.dentry->d_inode;
610 if (S_ISSOCK(inode->i_mode)) {
611 lo->file = file;
612 lo->sock = SOCKET_I(inode);
613 if (max_part > 0)
614 bdev->bd_invalidated = 1;
615 return 0;
616 } else {
617 fput(file);
618 }
619 }
620 return -EINVAL;
621 }
622
623 case NBD_SET_BLKSIZE:
624 lo->blksize = arg;
625 lo->bytesize &= ~(lo->blksize-1);
626 bdev->bd_inode->i_size = lo->bytesize;
627 set_blocksize(bdev, lo->blksize);
628 set_capacity(lo->disk, lo->bytesize >> 9);
629 return 0;
630
631 case NBD_SET_SIZE:
632 lo->bytesize = arg & ~(lo->blksize-1);
633 bdev->bd_inode->i_size = lo->bytesize;
634 set_blocksize(bdev, lo->blksize);
635 set_capacity(lo->disk, lo->bytesize >> 9);
636 return 0;
637
638 case NBD_SET_TIMEOUT:
639 lo->xmit_timeout = arg * HZ;
640 return 0;
641
642 case NBD_SET_SIZE_BLOCKS:
643 lo->bytesize = ((u64) arg) * lo->blksize;
644 bdev->bd_inode->i_size = lo->bytesize;
645 set_blocksize(bdev, lo->blksize);
646 set_capacity(lo->disk, lo->bytesize >> 9);
647 return 0;
648
649 case NBD_DO_IT: {
650 struct task_struct *thread;
651 struct file *file;
652 int error;
653
654 if (lo->pid)
655 return -EBUSY;
656 if (!lo->file)
657 return -EINVAL;
658
659 mutex_unlock(&lo->tx_lock);
660
661 thread = kthread_create(nbd_thread, lo, lo->disk->disk_name);
662 if (IS_ERR(thread)) {
663 mutex_lock(&lo->tx_lock);
664 return PTR_ERR(thread);
665 }
666 wake_up_process(thread);
667 error = nbd_do_it(lo);
668 kthread_stop(thread);
669
670 mutex_lock(&lo->tx_lock);
671 if (error)
672 return error;
673 sock_shutdown(lo, 0);
674 file = lo->file;
675 lo->file = NULL;
676 nbd_clear_que(lo);
677 printk(KERN_WARNING "%s: queue cleared\n", lo->disk->disk_name);
678 if (file)
679 fput(file);
680 lo->bytesize = 0;
681 bdev->bd_inode->i_size = 0;
682 set_capacity(lo->disk, 0);
683 if (max_part > 0)
684 ioctl_by_bdev(bdev, BLKRRPART, 0);
685 return lo->harderror;
686 }
687
688 case NBD_CLEAR_QUE:
689 /*
690 * This is for compatibility only. The queue is always cleared
691 * by NBD_DO_IT or NBD_CLEAR_SOCK.
692 */
693 BUG_ON(!lo->sock && !list_empty(&lo->queue_head));
694 return 0;
695
696 case NBD_PRINT_DEBUG:
697 printk(KERN_INFO "%s: next = %p, prev = %p, head = %p\n",
698 bdev->bd_disk->disk_name,
699 lo->queue_head.next, lo->queue_head.prev,
700 &lo->queue_head);
701 return 0;
702 }
703 return -ENOTTY;
704}
705
706static int nbd_ioctl(struct block_device *bdev, fmode_t mode,
707 unsigned int cmd, unsigned long arg)
708{
709 struct nbd_device *lo = bdev->bd_disk->private_data;
710 int error;
711
712 if (!capable(CAP_SYS_ADMIN))
713 return -EPERM;
714
715 BUG_ON(lo->magic != LO_MAGIC);
716
717 /* Anyone capable of this syscall can do *real bad* things */
718 dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n",
719 lo->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg);
720
721 mutex_lock(&lo->tx_lock);
722 error = __nbd_ioctl(bdev, lo, cmd, arg);
723 mutex_unlock(&lo->tx_lock);
724
725 return error;
726}
727
728static const struct block_device_operations nbd_fops =
729{
730 .owner = THIS_MODULE,
731 .ioctl = nbd_ioctl,
732};
733
734/*
735 * And here should be modules and kernel interface
736 * (Just smiley confuses emacs :-)
737 */
738
739static int __init nbd_init(void)
740{
741 int err = -ENOMEM;
742 int i;
743 int part_shift;
744
745 BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
746
747 if (max_part < 0) {
748 printk(KERN_CRIT "nbd: max_part must be >= 0\n");
749 return -EINVAL;
750 }
751
752 nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL);
753 if (!nbd_dev)
754 return -ENOMEM;
755
756 part_shift = 0;
757 if (max_part > 0) {
758 part_shift = fls(max_part);
759
760 /*
761 * Adjust max_part according to part_shift as it is exported
762 * to user space so that user can know the max number of
763 * partition kernel should be able to manage.
764 *
765 * Note that -1 is required because partition 0 is reserved
766 * for the whole disk.
767 */
768 max_part = (1UL << part_shift) - 1;
769 }
770
771 if ((1UL << part_shift) > DISK_MAX_PARTS)
772 return -EINVAL;
773
774 if (nbds_max > 1UL << (MINORBITS - part_shift))
775 return -EINVAL;
776
777 for (i = 0; i < nbds_max; i++) {
778 struct gendisk *disk = alloc_disk(1 << part_shift);
779 if (!disk)
780 goto out;
781 nbd_dev[i].disk = disk;
782 /*
783 * The new linux 2.5 block layer implementation requires
784 * every gendisk to have its very own request_queue struct.
785 * These structs are big so we dynamically allocate them.
786 */
787 disk->queue = blk_init_queue(do_nbd_request, &nbd_lock);
788 if (!disk->queue) {
789 put_disk(disk);
790 goto out;
791 }
792 /*
793 * Tell the block layer that we are not a rotational device
794 */
795 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue);
796 }
797
798 if (register_blkdev(NBD_MAJOR, "nbd")) {
799 err = -EIO;
800 goto out;
801 }
802
803 printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR);
804 dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags);
805
806 for (i = 0; i < nbds_max; i++) {
807 struct gendisk *disk = nbd_dev[i].disk;
808 nbd_dev[i].file = NULL;
809 nbd_dev[i].magic = LO_MAGIC;
810 nbd_dev[i].flags = 0;
811 INIT_LIST_HEAD(&nbd_dev[i].waiting_queue);
812 spin_lock_init(&nbd_dev[i].queue_lock);
813 INIT_LIST_HEAD(&nbd_dev[i].queue_head);
814 mutex_init(&nbd_dev[i].tx_lock);
815 init_waitqueue_head(&nbd_dev[i].active_wq);
816 init_waitqueue_head(&nbd_dev[i].waiting_wq);
817 nbd_dev[i].blksize = 1024;
818 nbd_dev[i].bytesize = 0;
819 disk->major = NBD_MAJOR;
820 disk->first_minor = i << part_shift;
821 disk->fops = &nbd_fops;
822 disk->private_data = &nbd_dev[i];
823 sprintf(disk->disk_name, "nbd%d", i);
824 set_capacity(disk, 0);
825 add_disk(disk);
826 }
827
828 return 0;
829out:
830 while (i--) {
831 blk_cleanup_queue(nbd_dev[i].disk->queue);
832 put_disk(nbd_dev[i].disk);
833 }
834 kfree(nbd_dev);
835 return err;
836}
837
838static void __exit nbd_cleanup(void)
839{
840 int i;
841 for (i = 0; i < nbds_max; i++) {
842 struct gendisk *disk = nbd_dev[i].disk;
843 nbd_dev[i].magic = 0;
844 if (disk) {
845 del_gendisk(disk);
846 blk_cleanup_queue(disk->queue);
847 put_disk(disk);
848 }
849 }
850 unregister_blkdev(NBD_MAJOR, "nbd");
851 kfree(nbd_dev);
852 printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR);
853}
854
855module_init(nbd_init);
856module_exit(nbd_cleanup);
857
858MODULE_DESCRIPTION("Network Block Device");
859MODULE_LICENSE("GPL");
860
861module_param(nbds_max, int, 0444);
862MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
863module_param(max_part, int, 0444);
864MODULE_PARM_DESC(max_part, "number of partitions per device (default: 0)");
865#ifndef NDEBUG
866module_param(debugflags, int, 0644);
867MODULE_PARM_DESC(debugflags, "flags for controlling debug output");
868#endif
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#define pr_fmt(fmt) "nbd: " fmt
15
16#include <linux/major.h>
17
18#include <linux/blkdev.h>
19#include <linux/module.h>
20#include <linux/init.h>
21#include <linux/sched.h>
22#include <linux/sched/mm.h>
23#include <linux/fs.h>
24#include <linux/bio.h>
25#include <linux/stat.h>
26#include <linux/errno.h>
27#include <linux/file.h>
28#include <linux/ioctl.h>
29#include <linux/mutex.h>
30#include <linux/compiler.h>
31#include <linux/completion.h>
32#include <linux/err.h>
33#include <linux/kernel.h>
34#include <linux/slab.h>
35#include <net/sock.h>
36#include <linux/net.h>
37#include <linux/kthread.h>
38#include <linux/types.h>
39#include <linux/debugfs.h>
40#include <linux/blk-mq.h>
41
42#include <linux/uaccess.h>
43#include <asm/types.h>
44
45#include <linux/nbd.h>
46#include <linux/nbd-netlink.h>
47#include <net/genetlink.h>
48
49#define CREATE_TRACE_POINTS
50#include <trace/events/nbd.h>
51
52static DEFINE_IDR(nbd_index_idr);
53static DEFINE_MUTEX(nbd_index_mutex);
54static struct workqueue_struct *nbd_del_wq;
55static int nbd_total_devices = 0;
56
57struct nbd_sock {
58 struct socket *sock;
59 struct mutex tx_lock;
60 struct request *pending;
61 int sent;
62 bool dead;
63 int fallback_index;
64 int cookie;
65};
66
67struct recv_thread_args {
68 struct work_struct work;
69 struct nbd_device *nbd;
70 int index;
71};
72
73struct link_dead_args {
74 struct work_struct work;
75 int index;
76};
77
78#define NBD_RT_TIMEDOUT 0
79#define NBD_RT_DISCONNECT_REQUESTED 1
80#define NBD_RT_DISCONNECTED 2
81#define NBD_RT_HAS_PID_FILE 3
82#define NBD_RT_HAS_CONFIG_REF 4
83#define NBD_RT_BOUND 5
84#define NBD_RT_DISCONNECT_ON_CLOSE 6
85#define NBD_RT_HAS_BACKEND_FILE 7
86
87#define NBD_DESTROY_ON_DISCONNECT 0
88#define NBD_DISCONNECT_REQUESTED 1
89
90struct nbd_config {
91 u32 flags;
92 unsigned long runtime_flags;
93 u64 dead_conn_timeout;
94
95 struct nbd_sock **socks;
96 int num_connections;
97 atomic_t live_connections;
98 wait_queue_head_t conn_wait;
99
100 atomic_t recv_threads;
101 wait_queue_head_t recv_wq;
102 unsigned int blksize_bits;
103 loff_t bytesize;
104#if IS_ENABLED(CONFIG_DEBUG_FS)
105 struct dentry *dbg_dir;
106#endif
107};
108
109static inline unsigned int nbd_blksize(struct nbd_config *config)
110{
111 return 1u << config->blksize_bits;
112}
113
114struct nbd_device {
115 struct blk_mq_tag_set tag_set;
116
117 int index;
118 refcount_t config_refs;
119 refcount_t refs;
120 struct nbd_config *config;
121 struct mutex config_lock;
122 struct gendisk *disk;
123 struct workqueue_struct *recv_workq;
124 struct work_struct remove_work;
125
126 struct list_head list;
127 struct task_struct *task_setup;
128
129 unsigned long flags;
130 pid_t pid; /* pid of nbd-client, if attached */
131
132 char *backend;
133};
134
135#define NBD_CMD_REQUEUED 1
136/*
137 * This flag will be set if nbd_queue_rq() succeed, and will be checked and
138 * cleared in completion. Both setting and clearing of the flag are protected
139 * by cmd->lock.
140 */
141#define NBD_CMD_INFLIGHT 2
142
143struct nbd_cmd {
144 struct nbd_device *nbd;
145 struct mutex lock;
146 int index;
147 int cookie;
148 int retries;
149 blk_status_t status;
150 unsigned long flags;
151 u32 cmd_cookie;
152};
153
154#if IS_ENABLED(CONFIG_DEBUG_FS)
155static struct dentry *nbd_dbg_dir;
156#endif
157
158#define nbd_name(nbd) ((nbd)->disk->disk_name)
159
160#define NBD_DEF_BLKSIZE_BITS 10
161
162static unsigned int nbds_max = 16;
163static int max_part = 16;
164static int part_shift;
165
166static int nbd_dev_dbg_init(struct nbd_device *nbd);
167static void nbd_dev_dbg_close(struct nbd_device *nbd);
168static void nbd_config_put(struct nbd_device *nbd);
169static void nbd_connect_reply(struct genl_info *info, int index);
170static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info);
171static void nbd_dead_link_work(struct work_struct *work);
172static void nbd_disconnect_and_put(struct nbd_device *nbd);
173
174static inline struct device *nbd_to_dev(struct nbd_device *nbd)
175{
176 return disk_to_dev(nbd->disk);
177}
178
179static void nbd_requeue_cmd(struct nbd_cmd *cmd)
180{
181 struct request *req = blk_mq_rq_from_pdu(cmd);
182
183 if (!test_and_set_bit(NBD_CMD_REQUEUED, &cmd->flags))
184 blk_mq_requeue_request(req, true);
185}
186
187#define NBD_COOKIE_BITS 32
188
189static u64 nbd_cmd_handle(struct nbd_cmd *cmd)
190{
191 struct request *req = blk_mq_rq_from_pdu(cmd);
192 u32 tag = blk_mq_unique_tag(req);
193 u64 cookie = cmd->cmd_cookie;
194
195 return (cookie << NBD_COOKIE_BITS) | tag;
196}
197
198static u32 nbd_handle_to_tag(u64 handle)
199{
200 return (u32)handle;
201}
202
203static u32 nbd_handle_to_cookie(u64 handle)
204{
205 return (u32)(handle >> NBD_COOKIE_BITS);
206}
207
208static const char *nbdcmd_to_ascii(int cmd)
209{
210 switch (cmd) {
211 case NBD_CMD_READ: return "read";
212 case NBD_CMD_WRITE: return "write";
213 case NBD_CMD_DISC: return "disconnect";
214 case NBD_CMD_FLUSH: return "flush";
215 case NBD_CMD_TRIM: return "trim/discard";
216 }
217 return "invalid";
218}
219
220static ssize_t pid_show(struct device *dev,
221 struct device_attribute *attr, char *buf)
222{
223 struct gendisk *disk = dev_to_disk(dev);
224 struct nbd_device *nbd = (struct nbd_device *)disk->private_data;
225
226 return sprintf(buf, "%d\n", nbd->pid);
227}
228
229static const struct device_attribute pid_attr = {
230 .attr = { .name = "pid", .mode = 0444},
231 .show = pid_show,
232};
233
234static ssize_t backend_show(struct device *dev,
235 struct device_attribute *attr, char *buf)
236{
237 struct gendisk *disk = dev_to_disk(dev);
238 struct nbd_device *nbd = (struct nbd_device *)disk->private_data;
239
240 return sprintf(buf, "%s\n", nbd->backend ?: "");
241}
242
243static const struct device_attribute backend_attr = {
244 .attr = { .name = "backend", .mode = 0444},
245 .show = backend_show,
246};
247
248static void nbd_dev_remove(struct nbd_device *nbd)
249{
250 struct gendisk *disk = nbd->disk;
251
252 del_gendisk(disk);
253 put_disk(disk);
254 blk_mq_free_tag_set(&nbd->tag_set);
255
256 /*
257 * Remove from idr after del_gendisk() completes, so if the same ID is
258 * reused, the following add_disk() will succeed.
259 */
260 mutex_lock(&nbd_index_mutex);
261 idr_remove(&nbd_index_idr, nbd->index);
262 mutex_unlock(&nbd_index_mutex);
263 destroy_workqueue(nbd->recv_workq);
264 kfree(nbd);
265}
266
267static void nbd_dev_remove_work(struct work_struct *work)
268{
269 nbd_dev_remove(container_of(work, struct nbd_device, remove_work));
270}
271
272static void nbd_put(struct nbd_device *nbd)
273{
274 if (!refcount_dec_and_test(&nbd->refs))
275 return;
276
277 /* Call del_gendisk() asynchrounously to prevent deadlock */
278 if (test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags))
279 queue_work(nbd_del_wq, &nbd->remove_work);
280 else
281 nbd_dev_remove(nbd);
282}
283
284static int nbd_disconnected(struct nbd_config *config)
285{
286 return test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags) ||
287 test_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags);
288}
289
290static void nbd_mark_nsock_dead(struct nbd_device *nbd, struct nbd_sock *nsock,
291 int notify)
292{
293 if (!nsock->dead && notify && !nbd_disconnected(nbd->config)) {
294 struct link_dead_args *args;
295 args = kmalloc(sizeof(struct link_dead_args), GFP_NOIO);
296 if (args) {
297 INIT_WORK(&args->work, nbd_dead_link_work);
298 args->index = nbd->index;
299 queue_work(system_wq, &args->work);
300 }
301 }
302 if (!nsock->dead) {
303 kernel_sock_shutdown(nsock->sock, SHUT_RDWR);
304 if (atomic_dec_return(&nbd->config->live_connections) == 0) {
305 if (test_and_clear_bit(NBD_RT_DISCONNECT_REQUESTED,
306 &nbd->config->runtime_flags)) {
307 set_bit(NBD_RT_DISCONNECTED,
308 &nbd->config->runtime_flags);
309 dev_info(nbd_to_dev(nbd),
310 "Disconnected due to user request.\n");
311 }
312 }
313 }
314 nsock->dead = true;
315 nsock->pending = NULL;
316 nsock->sent = 0;
317}
318
319static int nbd_set_size(struct nbd_device *nbd, loff_t bytesize,
320 loff_t blksize)
321{
322 if (!blksize)
323 blksize = 1u << NBD_DEF_BLKSIZE_BITS;
324
325 if (blk_validate_block_size(blksize))
326 return -EINVAL;
327
328 nbd->config->bytesize = bytesize;
329 nbd->config->blksize_bits = __ffs(blksize);
330
331 if (!nbd->pid)
332 return 0;
333
334 if (nbd->config->flags & NBD_FLAG_SEND_TRIM) {
335 nbd->disk->queue->limits.discard_granularity = blksize;
336 blk_queue_max_discard_sectors(nbd->disk->queue, UINT_MAX);
337 }
338 blk_queue_logical_block_size(nbd->disk->queue, blksize);
339 blk_queue_physical_block_size(nbd->disk->queue, blksize);
340
341 if (max_part)
342 set_bit(GD_NEED_PART_SCAN, &nbd->disk->state);
343 if (!set_capacity_and_notify(nbd->disk, bytesize >> 9))
344 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
345 return 0;
346}
347
348static void nbd_complete_rq(struct request *req)
349{
350 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
351
352 dev_dbg(nbd_to_dev(cmd->nbd), "request %p: %s\n", req,
353 cmd->status ? "failed" : "done");
354
355 blk_mq_end_request(req, cmd->status);
356}
357
358/*
359 * Forcibly shutdown the socket causing all listeners to error
360 */
361static void sock_shutdown(struct nbd_device *nbd)
362{
363 struct nbd_config *config = nbd->config;
364 int i;
365
366 if (config->num_connections == 0)
367 return;
368 if (test_and_set_bit(NBD_RT_DISCONNECTED, &config->runtime_flags))
369 return;
370
371 for (i = 0; i < config->num_connections; i++) {
372 struct nbd_sock *nsock = config->socks[i];
373 mutex_lock(&nsock->tx_lock);
374 nbd_mark_nsock_dead(nbd, nsock, 0);
375 mutex_unlock(&nsock->tx_lock);
376 }
377 dev_warn(disk_to_dev(nbd->disk), "shutting down sockets\n");
378}
379
380static u32 req_to_nbd_cmd_type(struct request *req)
381{
382 switch (req_op(req)) {
383 case REQ_OP_DISCARD:
384 return NBD_CMD_TRIM;
385 case REQ_OP_FLUSH:
386 return NBD_CMD_FLUSH;
387 case REQ_OP_WRITE:
388 return NBD_CMD_WRITE;
389 case REQ_OP_READ:
390 return NBD_CMD_READ;
391 default:
392 return U32_MAX;
393 }
394}
395
396static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req)
397{
398 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
399 struct nbd_device *nbd = cmd->nbd;
400 struct nbd_config *config;
401
402 if (!mutex_trylock(&cmd->lock))
403 return BLK_EH_RESET_TIMER;
404
405 if (!test_bit(NBD_CMD_INFLIGHT, &cmd->flags)) {
406 mutex_unlock(&cmd->lock);
407 return BLK_EH_DONE;
408 }
409
410 if (!refcount_inc_not_zero(&nbd->config_refs)) {
411 cmd->status = BLK_STS_TIMEOUT;
412 __clear_bit(NBD_CMD_INFLIGHT, &cmd->flags);
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 __clear_bit(NBD_CMD_INFLIGHT, &cmd->flags);
482 mutex_unlock(&cmd->lock);
483 sock_shutdown(nbd);
484 nbd_config_put(nbd);
485done:
486 blk_mq_complete_request(req);
487 return BLK_EH_DONE;
488}
489
490/*
491 * Send or receive packet. Return a positive value on success and
492 * negtive value on failue, and never return 0.
493 */
494static int sock_xmit(struct nbd_device *nbd, int index, int send,
495 struct iov_iter *iter, int msg_flags, int *sent)
496{
497 struct nbd_config *config = nbd->config;
498 struct socket *sock = config->socks[index]->sock;
499 int result;
500 struct msghdr msg;
501 unsigned int noreclaim_flag;
502
503 if (unlikely(!sock)) {
504 dev_err_ratelimited(disk_to_dev(nbd->disk),
505 "Attempted %s on closed socket in sock_xmit\n",
506 (send ? "send" : "recv"));
507 return -EINVAL;
508 }
509
510 msg.msg_iter = *iter;
511
512 noreclaim_flag = memalloc_noreclaim_save();
513 do {
514 sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC;
515 sock->sk->sk_use_task_frag = false;
516 msg.msg_name = NULL;
517 msg.msg_namelen = 0;
518 msg.msg_control = NULL;
519 msg.msg_controllen = 0;
520 msg.msg_flags = msg_flags | MSG_NOSIGNAL;
521
522 if (send)
523 result = sock_sendmsg(sock, &msg);
524 else
525 result = sock_recvmsg(sock, &msg, msg.msg_flags);
526
527 if (result <= 0) {
528 if (result == 0)
529 result = -EPIPE; /* short read */
530 break;
531 }
532 if (sent)
533 *sent += result;
534 } while (msg_data_left(&msg));
535
536 memalloc_noreclaim_restore(noreclaim_flag);
537
538 return result;
539}
540
541/*
542 * Different settings for sk->sk_sndtimeo can result in different return values
543 * if there is a signal pending when we enter sendmsg, because reasons?
544 */
545static inline int was_interrupted(int result)
546{
547 return result == -ERESTARTSYS || result == -EINTR;
548}
549
550/* always call with the tx_lock held */
551static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
552{
553 struct request *req = blk_mq_rq_from_pdu(cmd);
554 struct nbd_config *config = nbd->config;
555 struct nbd_sock *nsock = config->socks[index];
556 int result;
557 struct nbd_request request = {.magic = htonl(NBD_REQUEST_MAGIC)};
558 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
559 struct iov_iter from;
560 unsigned long size = blk_rq_bytes(req);
561 struct bio *bio;
562 u64 handle;
563 u32 type;
564 u32 nbd_cmd_flags = 0;
565 int sent = nsock->sent, skip = 0;
566
567 iov_iter_kvec(&from, ITER_SOURCE, &iov, 1, sizeof(request));
568
569 type = req_to_nbd_cmd_type(req);
570 if (type == U32_MAX)
571 return -EIO;
572
573 if (rq_data_dir(req) == WRITE &&
574 (config->flags & NBD_FLAG_READ_ONLY)) {
575 dev_err_ratelimited(disk_to_dev(nbd->disk),
576 "Write on read-only\n");
577 return -EIO;
578 }
579
580 if (req->cmd_flags & REQ_FUA)
581 nbd_cmd_flags |= NBD_CMD_FLAG_FUA;
582
583 /* We did a partial send previously, and we at least sent the whole
584 * request struct, so just go and send the rest of the pages in the
585 * request.
586 */
587 if (sent) {
588 if (sent >= sizeof(request)) {
589 skip = sent - sizeof(request);
590
591 /* initialize handle for tracing purposes */
592 handle = nbd_cmd_handle(cmd);
593
594 goto send_pages;
595 }
596 iov_iter_advance(&from, sent);
597 } else {
598 cmd->cmd_cookie++;
599 }
600 cmd->index = index;
601 cmd->cookie = nsock->cookie;
602 cmd->retries = 0;
603 request.type = htonl(type | nbd_cmd_flags);
604 if (type != NBD_CMD_FLUSH) {
605 request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
606 request.len = htonl(size);
607 }
608 handle = nbd_cmd_handle(cmd);
609 memcpy(request.handle, &handle, sizeof(handle));
610
611 trace_nbd_send_request(&request, nbd->index, blk_mq_rq_from_pdu(cmd));
612
613 dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n",
614 req, nbdcmd_to_ascii(type),
615 (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req));
616 result = sock_xmit(nbd, index, 1, &from,
617 (type == NBD_CMD_WRITE) ? MSG_MORE : 0, &sent);
618 trace_nbd_header_sent(req, handle);
619 if (result < 0) {
620 if (was_interrupted(result)) {
621 /* If we havne't sent anything we can just return BUSY,
622 * however if we have sent something we need to make
623 * sure we only allow this req to be sent until we are
624 * completely done.
625 */
626 if (sent) {
627 nsock->pending = req;
628 nsock->sent = sent;
629 }
630 set_bit(NBD_CMD_REQUEUED, &cmd->flags);
631 return BLK_STS_RESOURCE;
632 }
633 dev_err_ratelimited(disk_to_dev(nbd->disk),
634 "Send control failed (result %d)\n", result);
635 return -EAGAIN;
636 }
637send_pages:
638 if (type != NBD_CMD_WRITE)
639 goto out;
640
641 bio = req->bio;
642 while (bio) {
643 struct bio *next = bio->bi_next;
644 struct bvec_iter iter;
645 struct bio_vec bvec;
646
647 bio_for_each_segment(bvec, bio, iter) {
648 bool is_last = !next && bio_iter_last(bvec, iter);
649 int flags = is_last ? 0 : MSG_MORE;
650
651 dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n",
652 req, bvec.bv_len);
653 iov_iter_bvec(&from, ITER_SOURCE, &bvec, 1, bvec.bv_len);
654 if (skip) {
655 if (skip >= iov_iter_count(&from)) {
656 skip -= iov_iter_count(&from);
657 continue;
658 }
659 iov_iter_advance(&from, skip);
660 skip = 0;
661 }
662 result = sock_xmit(nbd, index, 1, &from, flags, &sent);
663 if (result < 0) {
664 if (was_interrupted(result)) {
665 /* We've already sent the header, we
666 * have no choice but to set pending and
667 * return BUSY.
668 */
669 nsock->pending = req;
670 nsock->sent = sent;
671 set_bit(NBD_CMD_REQUEUED, &cmd->flags);
672 return BLK_STS_RESOURCE;
673 }
674 dev_err(disk_to_dev(nbd->disk),
675 "Send data failed (result %d)\n",
676 result);
677 return -EAGAIN;
678 }
679 /*
680 * The completion might already have come in,
681 * so break for the last one instead of letting
682 * the iterator do it. This prevents use-after-free
683 * of the bio.
684 */
685 if (is_last)
686 break;
687 }
688 bio = next;
689 }
690out:
691 trace_nbd_payload_sent(req, handle);
692 nsock->pending = NULL;
693 nsock->sent = 0;
694 return 0;
695}
696
697static int nbd_read_reply(struct nbd_device *nbd, int index,
698 struct nbd_reply *reply)
699{
700 struct kvec iov = {.iov_base = reply, .iov_len = sizeof(*reply)};
701 struct iov_iter to;
702 int result;
703
704 reply->magic = 0;
705 iov_iter_kvec(&to, ITER_DEST, &iov, 1, sizeof(*reply));
706 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
707 if (result < 0) {
708 if (!nbd_disconnected(nbd->config))
709 dev_err(disk_to_dev(nbd->disk),
710 "Receive control failed (result %d)\n", result);
711 return result;
712 }
713
714 if (ntohl(reply->magic) != NBD_REPLY_MAGIC) {
715 dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n",
716 (unsigned long)ntohl(reply->magic));
717 return -EPROTO;
718 }
719
720 return 0;
721}
722
723/* NULL returned = something went wrong, inform userspace */
724static struct nbd_cmd *nbd_handle_reply(struct nbd_device *nbd, int index,
725 struct nbd_reply *reply)
726{
727 int result;
728 struct nbd_cmd *cmd;
729 struct request *req = NULL;
730 u64 handle;
731 u16 hwq;
732 u32 tag;
733 int ret = 0;
734
735 memcpy(&handle, reply->handle, sizeof(handle));
736 tag = nbd_handle_to_tag(handle);
737 hwq = blk_mq_unique_tag_to_hwq(tag);
738 if (hwq < nbd->tag_set.nr_hw_queues)
739 req = blk_mq_tag_to_rq(nbd->tag_set.tags[hwq],
740 blk_mq_unique_tag_to_tag(tag));
741 if (!req || !blk_mq_request_started(req)) {
742 dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%d) %p\n",
743 tag, req);
744 return ERR_PTR(-ENOENT);
745 }
746 trace_nbd_header_received(req, handle);
747 cmd = blk_mq_rq_to_pdu(req);
748
749 mutex_lock(&cmd->lock);
750 if (!test_bit(NBD_CMD_INFLIGHT, &cmd->flags)) {
751 dev_err(disk_to_dev(nbd->disk), "Suspicious reply %d (status %u flags %lu)",
752 tag, cmd->status, cmd->flags);
753 ret = -ENOENT;
754 goto out;
755 }
756 if (cmd->index != index) {
757 dev_err(disk_to_dev(nbd->disk), "Unexpected reply %d from different sock %d (expected %d)",
758 tag, index, cmd->index);
759 ret = -ENOENT;
760 goto out;
761 }
762 if (cmd->cmd_cookie != nbd_handle_to_cookie(handle)) {
763 dev_err(disk_to_dev(nbd->disk), "Double reply on req %p, cmd_cookie %u, handle cookie %u\n",
764 req, cmd->cmd_cookie, nbd_handle_to_cookie(handle));
765 ret = -ENOENT;
766 goto out;
767 }
768 if (cmd->status != BLK_STS_OK) {
769 dev_err(disk_to_dev(nbd->disk), "Command already handled %p\n",
770 req);
771 ret = -ENOENT;
772 goto out;
773 }
774 if (test_bit(NBD_CMD_REQUEUED, &cmd->flags)) {
775 dev_err(disk_to_dev(nbd->disk), "Raced with timeout on req %p\n",
776 req);
777 ret = -ENOENT;
778 goto out;
779 }
780 if (ntohl(reply->error)) {
781 dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n",
782 ntohl(reply->error));
783 cmd->status = BLK_STS_IOERR;
784 goto out;
785 }
786
787 dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", req);
788 if (rq_data_dir(req) != WRITE) {
789 struct req_iterator iter;
790 struct bio_vec bvec;
791 struct iov_iter to;
792
793 rq_for_each_segment(bvec, req, iter) {
794 iov_iter_bvec(&to, ITER_DEST, &bvec, 1, bvec.bv_len);
795 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
796 if (result < 0) {
797 dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
798 result);
799 /*
800 * If we've disconnected, we need to make sure we
801 * complete this request, otherwise error out
802 * and let the timeout stuff handle resubmitting
803 * this request onto another connection.
804 */
805 if (nbd_disconnected(nbd->config)) {
806 cmd->status = BLK_STS_IOERR;
807 goto out;
808 }
809 ret = -EIO;
810 goto out;
811 }
812 dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n",
813 req, bvec.bv_len);
814 }
815 }
816out:
817 trace_nbd_payload_received(req, handle);
818 mutex_unlock(&cmd->lock);
819 return ret ? ERR_PTR(ret) : cmd;
820}
821
822static void recv_work(struct work_struct *work)
823{
824 struct recv_thread_args *args = container_of(work,
825 struct recv_thread_args,
826 work);
827 struct nbd_device *nbd = args->nbd;
828 struct nbd_config *config = nbd->config;
829 struct request_queue *q = nbd->disk->queue;
830 struct nbd_sock *nsock;
831 struct nbd_cmd *cmd;
832 struct request *rq;
833
834 while (1) {
835 struct nbd_reply reply;
836
837 if (nbd_read_reply(nbd, args->index, &reply))
838 break;
839
840 /*
841 * Grab .q_usage_counter so request pool won't go away, then no
842 * request use-after-free is possible during nbd_handle_reply().
843 * If queue is frozen, there won't be any inflight requests, we
844 * needn't to handle the incoming garbage message.
845 */
846 if (!percpu_ref_tryget(&q->q_usage_counter)) {
847 dev_err(disk_to_dev(nbd->disk), "%s: no io inflight\n",
848 __func__);
849 break;
850 }
851
852 cmd = nbd_handle_reply(nbd, args->index, &reply);
853 if (IS_ERR(cmd)) {
854 percpu_ref_put(&q->q_usage_counter);
855 break;
856 }
857
858 rq = blk_mq_rq_from_pdu(cmd);
859 if (likely(!blk_should_fake_timeout(rq->q))) {
860 bool complete;
861
862 mutex_lock(&cmd->lock);
863 complete = __test_and_clear_bit(NBD_CMD_INFLIGHT,
864 &cmd->flags);
865 mutex_unlock(&cmd->lock);
866 if (complete)
867 blk_mq_complete_request(rq);
868 }
869 percpu_ref_put(&q->q_usage_counter);
870 }
871
872 nsock = config->socks[args->index];
873 mutex_lock(&nsock->tx_lock);
874 nbd_mark_nsock_dead(nbd, nsock, 1);
875 mutex_unlock(&nsock->tx_lock);
876
877 nbd_config_put(nbd);
878 atomic_dec(&config->recv_threads);
879 wake_up(&config->recv_wq);
880 kfree(args);
881}
882
883static bool nbd_clear_req(struct request *req, void *data)
884{
885 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
886
887 /* don't abort one completed request */
888 if (blk_mq_request_completed(req))
889 return true;
890
891 mutex_lock(&cmd->lock);
892 if (!__test_and_clear_bit(NBD_CMD_INFLIGHT, &cmd->flags)) {
893 mutex_unlock(&cmd->lock);
894 return true;
895 }
896 cmd->status = BLK_STS_IOERR;
897 mutex_unlock(&cmd->lock);
898
899 blk_mq_complete_request(req);
900 return true;
901}
902
903static void nbd_clear_que(struct nbd_device *nbd)
904{
905 blk_mq_quiesce_queue(nbd->disk->queue);
906 blk_mq_tagset_busy_iter(&nbd->tag_set, nbd_clear_req, NULL);
907 blk_mq_unquiesce_queue(nbd->disk->queue);
908 dev_dbg(disk_to_dev(nbd->disk), "queue cleared\n");
909}
910
911static int find_fallback(struct nbd_device *nbd, int index)
912{
913 struct nbd_config *config = nbd->config;
914 int new_index = -1;
915 struct nbd_sock *nsock = config->socks[index];
916 int fallback = nsock->fallback_index;
917
918 if (test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags))
919 return new_index;
920
921 if (config->num_connections <= 1) {
922 dev_err_ratelimited(disk_to_dev(nbd->disk),
923 "Dead connection, failed to find a fallback\n");
924 return new_index;
925 }
926
927 if (fallback >= 0 && fallback < config->num_connections &&
928 !config->socks[fallback]->dead)
929 return fallback;
930
931 if (nsock->fallback_index < 0 ||
932 nsock->fallback_index >= config->num_connections ||
933 config->socks[nsock->fallback_index]->dead) {
934 int i;
935 for (i = 0; i < config->num_connections; i++) {
936 if (i == index)
937 continue;
938 if (!config->socks[i]->dead) {
939 new_index = i;
940 break;
941 }
942 }
943 nsock->fallback_index = new_index;
944 if (new_index < 0) {
945 dev_err_ratelimited(disk_to_dev(nbd->disk),
946 "Dead connection, failed to find a fallback\n");
947 return new_index;
948 }
949 }
950 new_index = nsock->fallback_index;
951 return new_index;
952}
953
954static int wait_for_reconnect(struct nbd_device *nbd)
955{
956 struct nbd_config *config = nbd->config;
957 if (!config->dead_conn_timeout)
958 return 0;
959
960 if (!wait_event_timeout(config->conn_wait,
961 test_bit(NBD_RT_DISCONNECTED,
962 &config->runtime_flags) ||
963 atomic_read(&config->live_connections) > 0,
964 config->dead_conn_timeout))
965 return 0;
966
967 return !test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags);
968}
969
970static int nbd_handle_cmd(struct nbd_cmd *cmd, int index)
971{
972 struct request *req = blk_mq_rq_from_pdu(cmd);
973 struct nbd_device *nbd = cmd->nbd;
974 struct nbd_config *config;
975 struct nbd_sock *nsock;
976 int ret;
977
978 if (!refcount_inc_not_zero(&nbd->config_refs)) {
979 dev_err_ratelimited(disk_to_dev(nbd->disk),
980 "Socks array is empty\n");
981 return -EINVAL;
982 }
983 config = nbd->config;
984
985 if (index >= config->num_connections) {
986 dev_err_ratelimited(disk_to_dev(nbd->disk),
987 "Attempted send on invalid socket\n");
988 nbd_config_put(nbd);
989 return -EINVAL;
990 }
991 cmd->status = BLK_STS_OK;
992again:
993 nsock = config->socks[index];
994 mutex_lock(&nsock->tx_lock);
995 if (nsock->dead) {
996 int old_index = index;
997 index = find_fallback(nbd, index);
998 mutex_unlock(&nsock->tx_lock);
999 if (index < 0) {
1000 if (wait_for_reconnect(nbd)) {
1001 index = old_index;
1002 goto again;
1003 }
1004 /* All the sockets should already be down at this point,
1005 * we just want to make sure that DISCONNECTED is set so
1006 * any requests that come in that were queue'ed waiting
1007 * for the reconnect timer don't trigger the timer again
1008 * and instead just error out.
1009 */
1010 sock_shutdown(nbd);
1011 nbd_config_put(nbd);
1012 return -EIO;
1013 }
1014 goto again;
1015 }
1016
1017 /* Handle the case that we have a pending request that was partially
1018 * transmitted that _has_ to be serviced first. We need to call requeue
1019 * here so that it gets put _after_ the request that is already on the
1020 * dispatch list.
1021 */
1022 blk_mq_start_request(req);
1023 if (unlikely(nsock->pending && nsock->pending != req)) {
1024 nbd_requeue_cmd(cmd);
1025 ret = 0;
1026 goto out;
1027 }
1028 /*
1029 * Some failures are related to the link going down, so anything that
1030 * returns EAGAIN can be retried on a different socket.
1031 */
1032 ret = nbd_send_cmd(nbd, cmd, index);
1033 /*
1034 * Access to this flag is protected by cmd->lock, thus it's safe to set
1035 * the flag after nbd_send_cmd() succeed to send request to server.
1036 */
1037 if (!ret)
1038 __set_bit(NBD_CMD_INFLIGHT, &cmd->flags);
1039 else if (ret == -EAGAIN) {
1040 dev_err_ratelimited(disk_to_dev(nbd->disk),
1041 "Request send failed, requeueing\n");
1042 nbd_mark_nsock_dead(nbd, nsock, 1);
1043 nbd_requeue_cmd(cmd);
1044 ret = 0;
1045 }
1046out:
1047 mutex_unlock(&nsock->tx_lock);
1048 nbd_config_put(nbd);
1049 return ret;
1050}
1051
1052static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
1053 const struct blk_mq_queue_data *bd)
1054{
1055 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
1056 int ret;
1057
1058 /*
1059 * Since we look at the bio's to send the request over the network we
1060 * need to make sure the completion work doesn't mark this request done
1061 * before we are done doing our send. This keeps us from dereferencing
1062 * freed data if we have particularly fast completions (ie we get the
1063 * completion before we exit sock_xmit on the last bvec) or in the case
1064 * that the server is misbehaving (or there was an error) before we're
1065 * done sending everything over the wire.
1066 */
1067 mutex_lock(&cmd->lock);
1068 clear_bit(NBD_CMD_REQUEUED, &cmd->flags);
1069
1070 /* We can be called directly from the user space process, which means we
1071 * could possibly have signals pending so our sendmsg will fail. In
1072 * this case we need to return that we are busy, otherwise error out as
1073 * appropriate.
1074 */
1075 ret = nbd_handle_cmd(cmd, hctx->queue_num);
1076 if (ret < 0)
1077 ret = BLK_STS_IOERR;
1078 else if (!ret)
1079 ret = BLK_STS_OK;
1080 mutex_unlock(&cmd->lock);
1081
1082 return ret;
1083}
1084
1085static struct socket *nbd_get_socket(struct nbd_device *nbd, unsigned long fd,
1086 int *err)
1087{
1088 struct socket *sock;
1089
1090 *err = 0;
1091 sock = sockfd_lookup(fd, err);
1092 if (!sock)
1093 return NULL;
1094
1095 if (sock->ops->shutdown == sock_no_shutdown) {
1096 dev_err(disk_to_dev(nbd->disk), "Unsupported socket: shutdown callout must be supported.\n");
1097 *err = -EINVAL;
1098 sockfd_put(sock);
1099 return NULL;
1100 }
1101
1102 return sock;
1103}
1104
1105static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
1106 bool netlink)
1107{
1108 struct nbd_config *config = nbd->config;
1109 struct socket *sock;
1110 struct nbd_sock **socks;
1111 struct nbd_sock *nsock;
1112 int err;
1113
1114 sock = nbd_get_socket(nbd, arg, &err);
1115 if (!sock)
1116 return err;
1117
1118 /*
1119 * We need to make sure we don't get any errant requests while we're
1120 * reallocating the ->socks array.
1121 */
1122 blk_mq_freeze_queue(nbd->disk->queue);
1123
1124 if (!netlink && !nbd->task_setup &&
1125 !test_bit(NBD_RT_BOUND, &config->runtime_flags))
1126 nbd->task_setup = current;
1127
1128 if (!netlink &&
1129 (nbd->task_setup != current ||
1130 test_bit(NBD_RT_BOUND, &config->runtime_flags))) {
1131 dev_err(disk_to_dev(nbd->disk),
1132 "Device being setup by another task");
1133 err = -EBUSY;
1134 goto put_socket;
1135 }
1136
1137 nsock = kzalloc(sizeof(*nsock), GFP_KERNEL);
1138 if (!nsock) {
1139 err = -ENOMEM;
1140 goto put_socket;
1141 }
1142
1143 socks = krealloc(config->socks, (config->num_connections + 1) *
1144 sizeof(struct nbd_sock *), GFP_KERNEL);
1145 if (!socks) {
1146 kfree(nsock);
1147 err = -ENOMEM;
1148 goto put_socket;
1149 }
1150
1151 config->socks = socks;
1152
1153 nsock->fallback_index = -1;
1154 nsock->dead = false;
1155 mutex_init(&nsock->tx_lock);
1156 nsock->sock = sock;
1157 nsock->pending = NULL;
1158 nsock->sent = 0;
1159 nsock->cookie = 0;
1160 socks[config->num_connections++] = nsock;
1161 atomic_inc(&config->live_connections);
1162 blk_mq_unfreeze_queue(nbd->disk->queue);
1163
1164 return 0;
1165
1166put_socket:
1167 blk_mq_unfreeze_queue(nbd->disk->queue);
1168 sockfd_put(sock);
1169 return err;
1170}
1171
1172static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg)
1173{
1174 struct nbd_config *config = nbd->config;
1175 struct socket *sock, *old;
1176 struct recv_thread_args *args;
1177 int i;
1178 int err;
1179
1180 sock = nbd_get_socket(nbd, arg, &err);
1181 if (!sock)
1182 return err;
1183
1184 args = kzalloc(sizeof(*args), GFP_KERNEL);
1185 if (!args) {
1186 sockfd_put(sock);
1187 return -ENOMEM;
1188 }
1189
1190 for (i = 0; i < config->num_connections; i++) {
1191 struct nbd_sock *nsock = config->socks[i];
1192
1193 if (!nsock->dead)
1194 continue;
1195
1196 mutex_lock(&nsock->tx_lock);
1197 if (!nsock->dead) {
1198 mutex_unlock(&nsock->tx_lock);
1199 continue;
1200 }
1201 sk_set_memalloc(sock->sk);
1202 if (nbd->tag_set.timeout)
1203 sock->sk->sk_sndtimeo = nbd->tag_set.timeout;
1204 atomic_inc(&config->recv_threads);
1205 refcount_inc(&nbd->config_refs);
1206 old = nsock->sock;
1207 nsock->fallback_index = -1;
1208 nsock->sock = sock;
1209 nsock->dead = false;
1210 INIT_WORK(&args->work, recv_work);
1211 args->index = i;
1212 args->nbd = nbd;
1213 nsock->cookie++;
1214 mutex_unlock(&nsock->tx_lock);
1215 sockfd_put(old);
1216
1217 clear_bit(NBD_RT_DISCONNECTED, &config->runtime_flags);
1218
1219 /* We take the tx_mutex in an error path in the recv_work, so we
1220 * need to queue_work outside of the tx_mutex.
1221 */
1222 queue_work(nbd->recv_workq, &args->work);
1223
1224 atomic_inc(&config->live_connections);
1225 wake_up(&config->conn_wait);
1226 return 0;
1227 }
1228 sockfd_put(sock);
1229 kfree(args);
1230 return -ENOSPC;
1231}
1232
1233static void nbd_bdev_reset(struct nbd_device *nbd)
1234{
1235 if (disk_openers(nbd->disk) > 1)
1236 return;
1237 set_capacity(nbd->disk, 0);
1238}
1239
1240static void nbd_parse_flags(struct nbd_device *nbd)
1241{
1242 struct nbd_config *config = nbd->config;
1243 if (config->flags & NBD_FLAG_READ_ONLY)
1244 set_disk_ro(nbd->disk, true);
1245 else
1246 set_disk_ro(nbd->disk, false);
1247 if (config->flags & NBD_FLAG_SEND_FLUSH) {
1248 if (config->flags & NBD_FLAG_SEND_FUA)
1249 blk_queue_write_cache(nbd->disk->queue, true, true);
1250 else
1251 blk_queue_write_cache(nbd->disk->queue, true, false);
1252 }
1253 else
1254 blk_queue_write_cache(nbd->disk->queue, false, false);
1255}
1256
1257static void send_disconnects(struct nbd_device *nbd)
1258{
1259 struct nbd_config *config = nbd->config;
1260 struct nbd_request request = {
1261 .magic = htonl(NBD_REQUEST_MAGIC),
1262 .type = htonl(NBD_CMD_DISC),
1263 };
1264 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
1265 struct iov_iter from;
1266 int i, ret;
1267
1268 for (i = 0; i < config->num_connections; i++) {
1269 struct nbd_sock *nsock = config->socks[i];
1270
1271 iov_iter_kvec(&from, ITER_SOURCE, &iov, 1, sizeof(request));
1272 mutex_lock(&nsock->tx_lock);
1273 ret = sock_xmit(nbd, i, 1, &from, 0, NULL);
1274 if (ret < 0)
1275 dev_err(disk_to_dev(nbd->disk),
1276 "Send disconnect failed %d\n", ret);
1277 mutex_unlock(&nsock->tx_lock);
1278 }
1279}
1280
1281static int nbd_disconnect(struct nbd_device *nbd)
1282{
1283 struct nbd_config *config = nbd->config;
1284
1285 dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
1286 set_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags);
1287 set_bit(NBD_DISCONNECT_REQUESTED, &nbd->flags);
1288 send_disconnects(nbd);
1289 return 0;
1290}
1291
1292static void nbd_clear_sock(struct nbd_device *nbd)
1293{
1294 sock_shutdown(nbd);
1295 nbd_clear_que(nbd);
1296 nbd->task_setup = NULL;
1297}
1298
1299static void nbd_config_put(struct nbd_device *nbd)
1300{
1301 if (refcount_dec_and_mutex_lock(&nbd->config_refs,
1302 &nbd->config_lock)) {
1303 struct nbd_config *config = nbd->config;
1304 nbd_dev_dbg_close(nbd);
1305 invalidate_disk(nbd->disk);
1306 if (nbd->config->bytesize)
1307 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
1308 if (test_and_clear_bit(NBD_RT_HAS_PID_FILE,
1309 &config->runtime_flags))
1310 device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
1311 nbd->pid = 0;
1312 if (test_and_clear_bit(NBD_RT_HAS_BACKEND_FILE,
1313 &config->runtime_flags)) {
1314 device_remove_file(disk_to_dev(nbd->disk), &backend_attr);
1315 kfree(nbd->backend);
1316 nbd->backend = NULL;
1317 }
1318 nbd_clear_sock(nbd);
1319 if (config->num_connections) {
1320 int i;
1321 for (i = 0; i < config->num_connections; i++) {
1322 sockfd_put(config->socks[i]->sock);
1323 kfree(config->socks[i]);
1324 }
1325 kfree(config->socks);
1326 }
1327 kfree(nbd->config);
1328 nbd->config = NULL;
1329
1330 nbd->tag_set.timeout = 0;
1331 nbd->disk->queue->limits.discard_granularity = 0;
1332 blk_queue_max_discard_sectors(nbd->disk->queue, 0);
1333
1334 mutex_unlock(&nbd->config_lock);
1335 nbd_put(nbd);
1336 module_put(THIS_MODULE);
1337 }
1338}
1339
1340static int nbd_start_device(struct nbd_device *nbd)
1341{
1342 struct nbd_config *config = nbd->config;
1343 int num_connections = config->num_connections;
1344 int error = 0, i;
1345
1346 if (nbd->pid)
1347 return -EBUSY;
1348 if (!config->socks)
1349 return -EINVAL;
1350 if (num_connections > 1 &&
1351 !(config->flags & NBD_FLAG_CAN_MULTI_CONN)) {
1352 dev_err(disk_to_dev(nbd->disk), "server does not support multiple connections per device.\n");
1353 return -EINVAL;
1354 }
1355
1356 blk_mq_update_nr_hw_queues(&nbd->tag_set, config->num_connections);
1357 nbd->pid = task_pid_nr(current);
1358
1359 nbd_parse_flags(nbd);
1360
1361 error = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
1362 if (error) {
1363 dev_err(disk_to_dev(nbd->disk), "device_create_file failed for pid!\n");
1364 return error;
1365 }
1366 set_bit(NBD_RT_HAS_PID_FILE, &config->runtime_flags);
1367
1368 nbd_dev_dbg_init(nbd);
1369 for (i = 0; i < num_connections; i++) {
1370 struct recv_thread_args *args;
1371
1372 args = kzalloc(sizeof(*args), GFP_KERNEL);
1373 if (!args) {
1374 sock_shutdown(nbd);
1375 /*
1376 * If num_connections is m (2 < m),
1377 * and NO.1 ~ NO.n(1 < n < m) kzallocs are successful.
1378 * But NO.(n + 1) failed. We still have n recv threads.
1379 * So, add flush_workqueue here to prevent recv threads
1380 * dropping the last config_refs and trying to destroy
1381 * the workqueue from inside the workqueue.
1382 */
1383 if (i)
1384 flush_workqueue(nbd->recv_workq);
1385 return -ENOMEM;
1386 }
1387 sk_set_memalloc(config->socks[i]->sock->sk);
1388 if (nbd->tag_set.timeout)
1389 config->socks[i]->sock->sk->sk_sndtimeo =
1390 nbd->tag_set.timeout;
1391 atomic_inc(&config->recv_threads);
1392 refcount_inc(&nbd->config_refs);
1393 INIT_WORK(&args->work, recv_work);
1394 args->nbd = nbd;
1395 args->index = i;
1396 queue_work(nbd->recv_workq, &args->work);
1397 }
1398 return nbd_set_size(nbd, config->bytesize, nbd_blksize(config));
1399}
1400
1401static int nbd_start_device_ioctl(struct nbd_device *nbd)
1402{
1403 struct nbd_config *config = nbd->config;
1404 int ret;
1405
1406 ret = nbd_start_device(nbd);
1407 if (ret)
1408 return ret;
1409
1410 if (max_part)
1411 set_bit(GD_NEED_PART_SCAN, &nbd->disk->state);
1412 mutex_unlock(&nbd->config_lock);
1413 ret = wait_event_interruptible(config->recv_wq,
1414 atomic_read(&config->recv_threads) == 0);
1415 if (ret) {
1416 sock_shutdown(nbd);
1417 nbd_clear_que(nbd);
1418 }
1419
1420 flush_workqueue(nbd->recv_workq);
1421 mutex_lock(&nbd->config_lock);
1422 nbd_bdev_reset(nbd);
1423 /* user requested, ignore socket errors */
1424 if (test_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags))
1425 ret = 0;
1426 if (test_bit(NBD_RT_TIMEDOUT, &config->runtime_flags))
1427 ret = -ETIMEDOUT;
1428 return ret;
1429}
1430
1431static void nbd_clear_sock_ioctl(struct nbd_device *nbd,
1432 struct block_device *bdev)
1433{
1434 nbd_clear_sock(nbd);
1435 __invalidate_device(bdev, true);
1436 nbd_bdev_reset(nbd);
1437 if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF,
1438 &nbd->config->runtime_flags))
1439 nbd_config_put(nbd);
1440}
1441
1442static void nbd_set_cmd_timeout(struct nbd_device *nbd, u64 timeout)
1443{
1444 nbd->tag_set.timeout = timeout * HZ;
1445 if (timeout)
1446 blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ);
1447 else
1448 blk_queue_rq_timeout(nbd->disk->queue, 30 * HZ);
1449}
1450
1451/* Must be called with config_lock held */
1452static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
1453 unsigned int cmd, unsigned long arg)
1454{
1455 struct nbd_config *config = nbd->config;
1456 loff_t bytesize;
1457
1458 switch (cmd) {
1459 case NBD_DISCONNECT:
1460 return nbd_disconnect(nbd);
1461 case NBD_CLEAR_SOCK:
1462 nbd_clear_sock_ioctl(nbd, bdev);
1463 return 0;
1464 case NBD_SET_SOCK:
1465 return nbd_add_socket(nbd, arg, false);
1466 case NBD_SET_BLKSIZE:
1467 return nbd_set_size(nbd, config->bytesize, arg);
1468 case NBD_SET_SIZE:
1469 return nbd_set_size(nbd, arg, nbd_blksize(config));
1470 case NBD_SET_SIZE_BLOCKS:
1471 if (check_shl_overflow(arg, config->blksize_bits, &bytesize))
1472 return -EINVAL;
1473 return nbd_set_size(nbd, bytesize, nbd_blksize(config));
1474 case NBD_SET_TIMEOUT:
1475 nbd_set_cmd_timeout(nbd, arg);
1476 return 0;
1477
1478 case NBD_SET_FLAGS:
1479 config->flags = arg;
1480 return 0;
1481 case NBD_DO_IT:
1482 return nbd_start_device_ioctl(nbd);
1483 case NBD_CLEAR_QUE:
1484 /*
1485 * This is for compatibility only. The queue is always cleared
1486 * by NBD_DO_IT or NBD_CLEAR_SOCK.
1487 */
1488 return 0;
1489 case NBD_PRINT_DEBUG:
1490 /*
1491 * For compatibility only, we no longer keep a list of
1492 * outstanding requests.
1493 */
1494 return 0;
1495 }
1496 return -ENOTTY;
1497}
1498
1499static int nbd_ioctl(struct block_device *bdev, fmode_t mode,
1500 unsigned int cmd, unsigned long arg)
1501{
1502 struct nbd_device *nbd = bdev->bd_disk->private_data;
1503 struct nbd_config *config = nbd->config;
1504 int error = -EINVAL;
1505
1506 if (!capable(CAP_SYS_ADMIN))
1507 return -EPERM;
1508
1509 /* The block layer will pass back some non-nbd ioctls in case we have
1510 * special handling for them, but we don't so just return an error.
1511 */
1512 if (_IOC_TYPE(cmd) != 0xab)
1513 return -EINVAL;
1514
1515 mutex_lock(&nbd->config_lock);
1516
1517 /* Don't allow ioctl operations on a nbd device that was created with
1518 * netlink, unless it's DISCONNECT or CLEAR_SOCK, which are fine.
1519 */
1520 if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) ||
1521 (cmd == NBD_DISCONNECT || cmd == NBD_CLEAR_SOCK))
1522 error = __nbd_ioctl(bdev, nbd, cmd, arg);
1523 else
1524 dev_err(nbd_to_dev(nbd), "Cannot use ioctl interface on a netlink controlled device.\n");
1525 mutex_unlock(&nbd->config_lock);
1526 return error;
1527}
1528
1529static struct nbd_config *nbd_alloc_config(void)
1530{
1531 struct nbd_config *config;
1532
1533 if (!try_module_get(THIS_MODULE))
1534 return ERR_PTR(-ENODEV);
1535
1536 config = kzalloc(sizeof(struct nbd_config), GFP_NOFS);
1537 if (!config) {
1538 module_put(THIS_MODULE);
1539 return ERR_PTR(-ENOMEM);
1540 }
1541
1542 atomic_set(&config->recv_threads, 0);
1543 init_waitqueue_head(&config->recv_wq);
1544 init_waitqueue_head(&config->conn_wait);
1545 config->blksize_bits = NBD_DEF_BLKSIZE_BITS;
1546 atomic_set(&config->live_connections, 0);
1547 return config;
1548}
1549
1550static int nbd_open(struct block_device *bdev, fmode_t mode)
1551{
1552 struct nbd_device *nbd;
1553 int ret = 0;
1554
1555 mutex_lock(&nbd_index_mutex);
1556 nbd = bdev->bd_disk->private_data;
1557 if (!nbd) {
1558 ret = -ENXIO;
1559 goto out;
1560 }
1561 if (!refcount_inc_not_zero(&nbd->refs)) {
1562 ret = -ENXIO;
1563 goto out;
1564 }
1565 if (!refcount_inc_not_zero(&nbd->config_refs)) {
1566 struct nbd_config *config;
1567
1568 mutex_lock(&nbd->config_lock);
1569 if (refcount_inc_not_zero(&nbd->config_refs)) {
1570 mutex_unlock(&nbd->config_lock);
1571 goto out;
1572 }
1573 config = nbd_alloc_config();
1574 if (IS_ERR(config)) {
1575 ret = PTR_ERR(config);
1576 mutex_unlock(&nbd->config_lock);
1577 goto out;
1578 }
1579 nbd->config = config;
1580 refcount_set(&nbd->config_refs, 1);
1581 refcount_inc(&nbd->refs);
1582 mutex_unlock(&nbd->config_lock);
1583 if (max_part)
1584 set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
1585 } else if (nbd_disconnected(nbd->config)) {
1586 if (max_part)
1587 set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
1588 }
1589out:
1590 mutex_unlock(&nbd_index_mutex);
1591 return ret;
1592}
1593
1594static void nbd_release(struct gendisk *disk, fmode_t mode)
1595{
1596 struct nbd_device *nbd = disk->private_data;
1597
1598 if (test_bit(NBD_RT_DISCONNECT_ON_CLOSE, &nbd->config->runtime_flags) &&
1599 disk_openers(disk) == 0)
1600 nbd_disconnect_and_put(nbd);
1601
1602 nbd_config_put(nbd);
1603 nbd_put(nbd);
1604}
1605
1606static const struct block_device_operations nbd_fops =
1607{
1608 .owner = THIS_MODULE,
1609 .open = nbd_open,
1610 .release = nbd_release,
1611 .ioctl = nbd_ioctl,
1612 .compat_ioctl = nbd_ioctl,
1613};
1614
1615#if IS_ENABLED(CONFIG_DEBUG_FS)
1616
1617static int nbd_dbg_tasks_show(struct seq_file *s, void *unused)
1618{
1619 struct nbd_device *nbd = s->private;
1620
1621 if (nbd->pid)
1622 seq_printf(s, "recv: %d\n", nbd->pid);
1623
1624 return 0;
1625}
1626
1627DEFINE_SHOW_ATTRIBUTE(nbd_dbg_tasks);
1628
1629static int nbd_dbg_flags_show(struct seq_file *s, void *unused)
1630{
1631 struct nbd_device *nbd = s->private;
1632 u32 flags = nbd->config->flags;
1633
1634 seq_printf(s, "Hex: 0x%08x\n\n", flags);
1635
1636 seq_puts(s, "Known flags:\n");
1637
1638 if (flags & NBD_FLAG_HAS_FLAGS)
1639 seq_puts(s, "NBD_FLAG_HAS_FLAGS\n");
1640 if (flags & NBD_FLAG_READ_ONLY)
1641 seq_puts(s, "NBD_FLAG_READ_ONLY\n");
1642 if (flags & NBD_FLAG_SEND_FLUSH)
1643 seq_puts(s, "NBD_FLAG_SEND_FLUSH\n");
1644 if (flags & NBD_FLAG_SEND_FUA)
1645 seq_puts(s, "NBD_FLAG_SEND_FUA\n");
1646 if (flags & NBD_FLAG_SEND_TRIM)
1647 seq_puts(s, "NBD_FLAG_SEND_TRIM\n");
1648
1649 return 0;
1650}
1651
1652DEFINE_SHOW_ATTRIBUTE(nbd_dbg_flags);
1653
1654static int nbd_dev_dbg_init(struct nbd_device *nbd)
1655{
1656 struct dentry *dir;
1657 struct nbd_config *config = nbd->config;
1658
1659 if (!nbd_dbg_dir)
1660 return -EIO;
1661
1662 dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir);
1663 if (!dir) {
1664 dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s'\n",
1665 nbd_name(nbd));
1666 return -EIO;
1667 }
1668 config->dbg_dir = dir;
1669
1670 debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_fops);
1671 debugfs_create_u64("size_bytes", 0444, dir, &config->bytesize);
1672 debugfs_create_u32("timeout", 0444, dir, &nbd->tag_set.timeout);
1673 debugfs_create_u32("blocksize_bits", 0444, dir, &config->blksize_bits);
1674 debugfs_create_file("flags", 0444, dir, nbd, &nbd_dbg_flags_fops);
1675
1676 return 0;
1677}
1678
1679static void nbd_dev_dbg_close(struct nbd_device *nbd)
1680{
1681 debugfs_remove_recursive(nbd->config->dbg_dir);
1682}
1683
1684static int nbd_dbg_init(void)
1685{
1686 struct dentry *dbg_dir;
1687
1688 dbg_dir = debugfs_create_dir("nbd", NULL);
1689 if (!dbg_dir)
1690 return -EIO;
1691
1692 nbd_dbg_dir = dbg_dir;
1693
1694 return 0;
1695}
1696
1697static void nbd_dbg_close(void)
1698{
1699 debugfs_remove_recursive(nbd_dbg_dir);
1700}
1701
1702#else /* IS_ENABLED(CONFIG_DEBUG_FS) */
1703
1704static int nbd_dev_dbg_init(struct nbd_device *nbd)
1705{
1706 return 0;
1707}
1708
1709static void nbd_dev_dbg_close(struct nbd_device *nbd)
1710{
1711}
1712
1713static int nbd_dbg_init(void)
1714{
1715 return 0;
1716}
1717
1718static void nbd_dbg_close(void)
1719{
1720}
1721
1722#endif
1723
1724static int nbd_init_request(struct blk_mq_tag_set *set, struct request *rq,
1725 unsigned int hctx_idx, unsigned int numa_node)
1726{
1727 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq);
1728 cmd->nbd = set->driver_data;
1729 cmd->flags = 0;
1730 mutex_init(&cmd->lock);
1731 return 0;
1732}
1733
1734static const struct blk_mq_ops nbd_mq_ops = {
1735 .queue_rq = nbd_queue_rq,
1736 .complete = nbd_complete_rq,
1737 .init_request = nbd_init_request,
1738 .timeout = nbd_xmit_timeout,
1739};
1740
1741static struct nbd_device *nbd_dev_add(int index, unsigned int refs)
1742{
1743 struct nbd_device *nbd;
1744 struct gendisk *disk;
1745 int err = -ENOMEM;
1746
1747 nbd = kzalloc(sizeof(struct nbd_device), GFP_KERNEL);
1748 if (!nbd)
1749 goto out;
1750
1751 nbd->tag_set.ops = &nbd_mq_ops;
1752 nbd->tag_set.nr_hw_queues = 1;
1753 nbd->tag_set.queue_depth = 128;
1754 nbd->tag_set.numa_node = NUMA_NO_NODE;
1755 nbd->tag_set.cmd_size = sizeof(struct nbd_cmd);
1756 nbd->tag_set.flags = BLK_MQ_F_SHOULD_MERGE |
1757 BLK_MQ_F_BLOCKING;
1758 nbd->tag_set.driver_data = nbd;
1759 INIT_WORK(&nbd->remove_work, nbd_dev_remove_work);
1760 nbd->backend = NULL;
1761
1762 err = blk_mq_alloc_tag_set(&nbd->tag_set);
1763 if (err)
1764 goto out_free_nbd;
1765
1766 mutex_lock(&nbd_index_mutex);
1767 if (index >= 0) {
1768 err = idr_alloc(&nbd_index_idr, nbd, index, index + 1,
1769 GFP_KERNEL);
1770 if (err == -ENOSPC)
1771 err = -EEXIST;
1772 } else {
1773 err = idr_alloc(&nbd_index_idr, nbd, 0, 0, GFP_KERNEL);
1774 if (err >= 0)
1775 index = err;
1776 }
1777 nbd->index = index;
1778 mutex_unlock(&nbd_index_mutex);
1779 if (err < 0)
1780 goto out_free_tags;
1781
1782 disk = blk_mq_alloc_disk(&nbd->tag_set, NULL);
1783 if (IS_ERR(disk)) {
1784 err = PTR_ERR(disk);
1785 goto out_free_idr;
1786 }
1787 nbd->disk = disk;
1788
1789 nbd->recv_workq = alloc_workqueue("nbd%d-recv",
1790 WQ_MEM_RECLAIM | WQ_HIGHPRI |
1791 WQ_UNBOUND, 0, nbd->index);
1792 if (!nbd->recv_workq) {
1793 dev_err(disk_to_dev(nbd->disk), "Could not allocate knbd recv work queue.\n");
1794 err = -ENOMEM;
1795 goto out_err_disk;
1796 }
1797
1798 /*
1799 * Tell the block layer that we are not a rotational device
1800 */
1801 blk_queue_flag_set(QUEUE_FLAG_NONROT, disk->queue);
1802 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, disk->queue);
1803 disk->queue->limits.discard_granularity = 0;
1804 blk_queue_max_discard_sectors(disk->queue, 0);
1805 blk_queue_max_segment_size(disk->queue, UINT_MAX);
1806 blk_queue_max_segments(disk->queue, USHRT_MAX);
1807 blk_queue_max_hw_sectors(disk->queue, 65536);
1808 disk->queue->limits.max_sectors = 256;
1809
1810 mutex_init(&nbd->config_lock);
1811 refcount_set(&nbd->config_refs, 0);
1812 /*
1813 * Start out with a zero references to keep other threads from using
1814 * this device until it is fully initialized.
1815 */
1816 refcount_set(&nbd->refs, 0);
1817 INIT_LIST_HEAD(&nbd->list);
1818 disk->major = NBD_MAJOR;
1819 disk->first_minor = index << part_shift;
1820 disk->minors = 1 << part_shift;
1821 disk->fops = &nbd_fops;
1822 disk->private_data = nbd;
1823 sprintf(disk->disk_name, "nbd%d", index);
1824 err = add_disk(disk);
1825 if (err)
1826 goto out_free_work;
1827
1828 /*
1829 * Now publish the device.
1830 */
1831 refcount_set(&nbd->refs, refs);
1832 nbd_total_devices++;
1833 return nbd;
1834
1835out_free_work:
1836 destroy_workqueue(nbd->recv_workq);
1837out_err_disk:
1838 put_disk(disk);
1839out_free_idr:
1840 mutex_lock(&nbd_index_mutex);
1841 idr_remove(&nbd_index_idr, index);
1842 mutex_unlock(&nbd_index_mutex);
1843out_free_tags:
1844 blk_mq_free_tag_set(&nbd->tag_set);
1845out_free_nbd:
1846 kfree(nbd);
1847out:
1848 return ERR_PTR(err);
1849}
1850
1851static struct nbd_device *nbd_find_get_unused(void)
1852{
1853 struct nbd_device *nbd;
1854 int id;
1855
1856 lockdep_assert_held(&nbd_index_mutex);
1857
1858 idr_for_each_entry(&nbd_index_idr, nbd, id) {
1859 if (refcount_read(&nbd->config_refs) ||
1860 test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags))
1861 continue;
1862 if (refcount_inc_not_zero(&nbd->refs))
1863 return nbd;
1864 }
1865
1866 return NULL;
1867}
1868
1869/* Netlink interface. */
1870static const struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = {
1871 [NBD_ATTR_INDEX] = { .type = NLA_U32 },
1872 [NBD_ATTR_SIZE_BYTES] = { .type = NLA_U64 },
1873 [NBD_ATTR_BLOCK_SIZE_BYTES] = { .type = NLA_U64 },
1874 [NBD_ATTR_TIMEOUT] = { .type = NLA_U64 },
1875 [NBD_ATTR_SERVER_FLAGS] = { .type = NLA_U64 },
1876 [NBD_ATTR_CLIENT_FLAGS] = { .type = NLA_U64 },
1877 [NBD_ATTR_SOCKETS] = { .type = NLA_NESTED},
1878 [NBD_ATTR_DEAD_CONN_TIMEOUT] = { .type = NLA_U64 },
1879 [NBD_ATTR_DEVICE_LIST] = { .type = NLA_NESTED},
1880 [NBD_ATTR_BACKEND_IDENTIFIER] = { .type = NLA_STRING},
1881};
1882
1883static const struct nla_policy nbd_sock_policy[NBD_SOCK_MAX + 1] = {
1884 [NBD_SOCK_FD] = { .type = NLA_U32 },
1885};
1886
1887/* We don't use this right now since we don't parse the incoming list, but we
1888 * still want it here so userspace knows what to expect.
1889 */
1890static const struct nla_policy __attribute__((unused))
1891nbd_device_policy[NBD_DEVICE_ATTR_MAX + 1] = {
1892 [NBD_DEVICE_INDEX] = { .type = NLA_U32 },
1893 [NBD_DEVICE_CONNECTED] = { .type = NLA_U8 },
1894};
1895
1896static int nbd_genl_size_set(struct genl_info *info, struct nbd_device *nbd)
1897{
1898 struct nbd_config *config = nbd->config;
1899 u64 bsize = nbd_blksize(config);
1900 u64 bytes = config->bytesize;
1901
1902 if (info->attrs[NBD_ATTR_SIZE_BYTES])
1903 bytes = nla_get_u64(info->attrs[NBD_ATTR_SIZE_BYTES]);
1904
1905 if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES])
1906 bsize = nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]);
1907
1908 if (bytes != config->bytesize || bsize != nbd_blksize(config))
1909 return nbd_set_size(nbd, bytes, bsize);
1910 return 0;
1911}
1912
1913static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
1914{
1915 struct nbd_device *nbd;
1916 struct nbd_config *config;
1917 int index = -1;
1918 int ret;
1919 bool put_dev = false;
1920
1921 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1922 return -EPERM;
1923
1924 if (info->attrs[NBD_ATTR_INDEX]) {
1925 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1926
1927 /*
1928 * Too big first_minor can cause duplicate creation of
1929 * sysfs files/links, since index << part_shift might overflow, or
1930 * MKDEV() expect that the max bits of first_minor is 20.
1931 */
1932 if (index < 0 || index > MINORMASK >> part_shift) {
1933 pr_err("illegal input index %d\n", index);
1934 return -EINVAL;
1935 }
1936 }
1937 if (!info->attrs[NBD_ATTR_SOCKETS]) {
1938 pr_err("must specify at least one socket\n");
1939 return -EINVAL;
1940 }
1941 if (!info->attrs[NBD_ATTR_SIZE_BYTES]) {
1942 pr_err("must specify a size in bytes for the device\n");
1943 return -EINVAL;
1944 }
1945again:
1946 mutex_lock(&nbd_index_mutex);
1947 if (index == -1) {
1948 nbd = nbd_find_get_unused();
1949 } else {
1950 nbd = idr_find(&nbd_index_idr, index);
1951 if (nbd) {
1952 if ((test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags) &&
1953 test_bit(NBD_DISCONNECT_REQUESTED, &nbd->flags)) ||
1954 !refcount_inc_not_zero(&nbd->refs)) {
1955 mutex_unlock(&nbd_index_mutex);
1956 pr_err("device at index %d is going down\n",
1957 index);
1958 return -EINVAL;
1959 }
1960 }
1961 }
1962 mutex_unlock(&nbd_index_mutex);
1963
1964 if (!nbd) {
1965 nbd = nbd_dev_add(index, 2);
1966 if (IS_ERR(nbd)) {
1967 pr_err("failed to add new device\n");
1968 return PTR_ERR(nbd);
1969 }
1970 }
1971
1972 mutex_lock(&nbd->config_lock);
1973 if (refcount_read(&nbd->config_refs)) {
1974 mutex_unlock(&nbd->config_lock);
1975 nbd_put(nbd);
1976 if (index == -1)
1977 goto again;
1978 pr_err("nbd%d already in use\n", index);
1979 return -EBUSY;
1980 }
1981 if (WARN_ON(nbd->config)) {
1982 mutex_unlock(&nbd->config_lock);
1983 nbd_put(nbd);
1984 return -EINVAL;
1985 }
1986 config = nbd_alloc_config();
1987 if (IS_ERR(config)) {
1988 mutex_unlock(&nbd->config_lock);
1989 nbd_put(nbd);
1990 pr_err("couldn't allocate config\n");
1991 return PTR_ERR(config);
1992 }
1993 nbd->config = config;
1994 refcount_set(&nbd->config_refs, 1);
1995 set_bit(NBD_RT_BOUND, &config->runtime_flags);
1996
1997 ret = nbd_genl_size_set(info, nbd);
1998 if (ret)
1999 goto out;
2000
2001 if (info->attrs[NBD_ATTR_TIMEOUT])
2002 nbd_set_cmd_timeout(nbd,
2003 nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]));
2004 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
2005 config->dead_conn_timeout =
2006 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
2007 config->dead_conn_timeout *= HZ;
2008 }
2009 if (info->attrs[NBD_ATTR_SERVER_FLAGS])
2010 config->flags =
2011 nla_get_u64(info->attrs[NBD_ATTR_SERVER_FLAGS]);
2012 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
2013 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
2014 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
2015 /*
2016 * We have 1 ref to keep the device around, and then 1
2017 * ref for our current operation here, which will be
2018 * inherited by the config. If we already have
2019 * DESTROY_ON_DISCONNECT set then we know we don't have
2020 * that extra ref already held so we don't need the
2021 * put_dev.
2022 */
2023 if (!test_and_set_bit(NBD_DESTROY_ON_DISCONNECT,
2024 &nbd->flags))
2025 put_dev = true;
2026 } else {
2027 if (test_and_clear_bit(NBD_DESTROY_ON_DISCONNECT,
2028 &nbd->flags))
2029 refcount_inc(&nbd->refs);
2030 }
2031 if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {
2032 set_bit(NBD_RT_DISCONNECT_ON_CLOSE,
2033 &config->runtime_flags);
2034 }
2035 }
2036
2037 if (info->attrs[NBD_ATTR_SOCKETS]) {
2038 struct nlattr *attr;
2039 int rem, fd;
2040
2041 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
2042 rem) {
2043 struct nlattr *socks[NBD_SOCK_MAX+1];
2044
2045 if (nla_type(attr) != NBD_SOCK_ITEM) {
2046 pr_err("socks must be embedded in a SOCK_ITEM attr\n");
2047 ret = -EINVAL;
2048 goto out;
2049 }
2050 ret = nla_parse_nested_deprecated(socks, NBD_SOCK_MAX,
2051 attr,
2052 nbd_sock_policy,
2053 info->extack);
2054 if (ret != 0) {
2055 pr_err("error processing sock list\n");
2056 ret = -EINVAL;
2057 goto out;
2058 }
2059 if (!socks[NBD_SOCK_FD])
2060 continue;
2061 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
2062 ret = nbd_add_socket(nbd, fd, true);
2063 if (ret)
2064 goto out;
2065 }
2066 }
2067 ret = nbd_start_device(nbd);
2068 if (ret)
2069 goto out;
2070 if (info->attrs[NBD_ATTR_BACKEND_IDENTIFIER]) {
2071 nbd->backend = nla_strdup(info->attrs[NBD_ATTR_BACKEND_IDENTIFIER],
2072 GFP_KERNEL);
2073 if (!nbd->backend) {
2074 ret = -ENOMEM;
2075 goto out;
2076 }
2077 }
2078 ret = device_create_file(disk_to_dev(nbd->disk), &backend_attr);
2079 if (ret) {
2080 dev_err(disk_to_dev(nbd->disk),
2081 "device_create_file failed for backend!\n");
2082 goto out;
2083 }
2084 set_bit(NBD_RT_HAS_BACKEND_FILE, &config->runtime_flags);
2085out:
2086 mutex_unlock(&nbd->config_lock);
2087 if (!ret) {
2088 set_bit(NBD_RT_HAS_CONFIG_REF, &config->runtime_flags);
2089 refcount_inc(&nbd->config_refs);
2090 nbd_connect_reply(info, nbd->index);
2091 }
2092 nbd_config_put(nbd);
2093 if (put_dev)
2094 nbd_put(nbd);
2095 return ret;
2096}
2097
2098static void nbd_disconnect_and_put(struct nbd_device *nbd)
2099{
2100 mutex_lock(&nbd->config_lock);
2101 nbd_disconnect(nbd);
2102 sock_shutdown(nbd);
2103 wake_up(&nbd->config->conn_wait);
2104 /*
2105 * Make sure recv thread has finished, we can safely call nbd_clear_que()
2106 * to cancel the inflight I/Os.
2107 */
2108 flush_workqueue(nbd->recv_workq);
2109 nbd_clear_que(nbd);
2110 nbd->task_setup = NULL;
2111 mutex_unlock(&nbd->config_lock);
2112
2113 if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF,
2114 &nbd->config->runtime_flags))
2115 nbd_config_put(nbd);
2116}
2117
2118static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info)
2119{
2120 struct nbd_device *nbd;
2121 int index;
2122
2123 if (!netlink_capable(skb, CAP_SYS_ADMIN))
2124 return -EPERM;
2125
2126 if (!info->attrs[NBD_ATTR_INDEX]) {
2127 pr_err("must specify an index to disconnect\n");
2128 return -EINVAL;
2129 }
2130 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2131 mutex_lock(&nbd_index_mutex);
2132 nbd = idr_find(&nbd_index_idr, index);
2133 if (!nbd) {
2134 mutex_unlock(&nbd_index_mutex);
2135 pr_err("couldn't find device at index %d\n", index);
2136 return -EINVAL;
2137 }
2138 if (!refcount_inc_not_zero(&nbd->refs)) {
2139 mutex_unlock(&nbd_index_mutex);
2140 pr_err("device at index %d is going down\n", index);
2141 return -EINVAL;
2142 }
2143 mutex_unlock(&nbd_index_mutex);
2144 if (!refcount_inc_not_zero(&nbd->config_refs))
2145 goto put_nbd;
2146 nbd_disconnect_and_put(nbd);
2147 nbd_config_put(nbd);
2148put_nbd:
2149 nbd_put(nbd);
2150 return 0;
2151}
2152
2153static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info)
2154{
2155 struct nbd_device *nbd = NULL;
2156 struct nbd_config *config;
2157 int index;
2158 int ret = 0;
2159 bool put_dev = false;
2160
2161 if (!netlink_capable(skb, CAP_SYS_ADMIN))
2162 return -EPERM;
2163
2164 if (!info->attrs[NBD_ATTR_INDEX]) {
2165 pr_err("must specify a device to reconfigure\n");
2166 return -EINVAL;
2167 }
2168 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2169 mutex_lock(&nbd_index_mutex);
2170 nbd = idr_find(&nbd_index_idr, index);
2171 if (!nbd) {
2172 mutex_unlock(&nbd_index_mutex);
2173 pr_err("couldn't find a device at index %d\n", index);
2174 return -EINVAL;
2175 }
2176 if (nbd->backend) {
2177 if (info->attrs[NBD_ATTR_BACKEND_IDENTIFIER]) {
2178 if (nla_strcmp(info->attrs[NBD_ATTR_BACKEND_IDENTIFIER],
2179 nbd->backend)) {
2180 mutex_unlock(&nbd_index_mutex);
2181 dev_err(nbd_to_dev(nbd),
2182 "backend image doesn't match with %s\n",
2183 nbd->backend);
2184 return -EINVAL;
2185 }
2186 } else {
2187 mutex_unlock(&nbd_index_mutex);
2188 dev_err(nbd_to_dev(nbd), "must specify backend\n");
2189 return -EINVAL;
2190 }
2191 }
2192 if (!refcount_inc_not_zero(&nbd->refs)) {
2193 mutex_unlock(&nbd_index_mutex);
2194 pr_err("device at index %d is going down\n", index);
2195 return -EINVAL;
2196 }
2197 mutex_unlock(&nbd_index_mutex);
2198
2199 if (!refcount_inc_not_zero(&nbd->config_refs)) {
2200 dev_err(nbd_to_dev(nbd),
2201 "not configured, cannot reconfigure\n");
2202 nbd_put(nbd);
2203 return -EINVAL;
2204 }
2205
2206 mutex_lock(&nbd->config_lock);
2207 config = nbd->config;
2208 if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) ||
2209 !nbd->pid) {
2210 dev_err(nbd_to_dev(nbd),
2211 "not configured, cannot reconfigure\n");
2212 ret = -EINVAL;
2213 goto out;
2214 }
2215
2216 ret = nbd_genl_size_set(info, nbd);
2217 if (ret)
2218 goto out;
2219
2220 if (info->attrs[NBD_ATTR_TIMEOUT])
2221 nbd_set_cmd_timeout(nbd,
2222 nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]));
2223 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
2224 config->dead_conn_timeout =
2225 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
2226 config->dead_conn_timeout *= HZ;
2227 }
2228 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
2229 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
2230 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
2231 if (!test_and_set_bit(NBD_DESTROY_ON_DISCONNECT,
2232 &nbd->flags))
2233 put_dev = true;
2234 } else {
2235 if (test_and_clear_bit(NBD_DESTROY_ON_DISCONNECT,
2236 &nbd->flags))
2237 refcount_inc(&nbd->refs);
2238 }
2239
2240 if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {
2241 set_bit(NBD_RT_DISCONNECT_ON_CLOSE,
2242 &config->runtime_flags);
2243 } else {
2244 clear_bit(NBD_RT_DISCONNECT_ON_CLOSE,
2245 &config->runtime_flags);
2246 }
2247 }
2248
2249 if (info->attrs[NBD_ATTR_SOCKETS]) {
2250 struct nlattr *attr;
2251 int rem, fd;
2252
2253 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
2254 rem) {
2255 struct nlattr *socks[NBD_SOCK_MAX+1];
2256
2257 if (nla_type(attr) != NBD_SOCK_ITEM) {
2258 pr_err("socks must be embedded in a SOCK_ITEM attr\n");
2259 ret = -EINVAL;
2260 goto out;
2261 }
2262 ret = nla_parse_nested_deprecated(socks, NBD_SOCK_MAX,
2263 attr,
2264 nbd_sock_policy,
2265 info->extack);
2266 if (ret != 0) {
2267 pr_err("error processing sock list\n");
2268 ret = -EINVAL;
2269 goto out;
2270 }
2271 if (!socks[NBD_SOCK_FD])
2272 continue;
2273 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
2274 ret = nbd_reconnect_socket(nbd, fd);
2275 if (ret) {
2276 if (ret == -ENOSPC)
2277 ret = 0;
2278 goto out;
2279 }
2280 dev_info(nbd_to_dev(nbd), "reconnected socket\n");
2281 }
2282 }
2283out:
2284 mutex_unlock(&nbd->config_lock);
2285 nbd_config_put(nbd);
2286 nbd_put(nbd);
2287 if (put_dev)
2288 nbd_put(nbd);
2289 return ret;
2290}
2291
2292static const struct genl_small_ops nbd_connect_genl_ops[] = {
2293 {
2294 .cmd = NBD_CMD_CONNECT,
2295 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2296 .doit = nbd_genl_connect,
2297 },
2298 {
2299 .cmd = NBD_CMD_DISCONNECT,
2300 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2301 .doit = nbd_genl_disconnect,
2302 },
2303 {
2304 .cmd = NBD_CMD_RECONFIGURE,
2305 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2306 .doit = nbd_genl_reconfigure,
2307 },
2308 {
2309 .cmd = NBD_CMD_STATUS,
2310 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2311 .doit = nbd_genl_status,
2312 },
2313};
2314
2315static const struct genl_multicast_group nbd_mcast_grps[] = {
2316 { .name = NBD_GENL_MCAST_GROUP_NAME, },
2317};
2318
2319static struct genl_family nbd_genl_family __ro_after_init = {
2320 .hdrsize = 0,
2321 .name = NBD_GENL_FAMILY_NAME,
2322 .version = NBD_GENL_VERSION,
2323 .module = THIS_MODULE,
2324 .small_ops = nbd_connect_genl_ops,
2325 .n_small_ops = ARRAY_SIZE(nbd_connect_genl_ops),
2326 .resv_start_op = NBD_CMD_STATUS + 1,
2327 .maxattr = NBD_ATTR_MAX,
2328 .policy = nbd_attr_policy,
2329 .mcgrps = nbd_mcast_grps,
2330 .n_mcgrps = ARRAY_SIZE(nbd_mcast_grps),
2331};
2332
2333static int populate_nbd_status(struct nbd_device *nbd, struct sk_buff *reply)
2334{
2335 struct nlattr *dev_opt;
2336 u8 connected = 0;
2337 int ret;
2338
2339 /* This is a little racey, but for status it's ok. The
2340 * reason we don't take a ref here is because we can't
2341 * take a ref in the index == -1 case as we would need
2342 * to put under the nbd_index_mutex, which could
2343 * deadlock if we are configured to remove ourselves
2344 * once we're disconnected.
2345 */
2346 if (refcount_read(&nbd->config_refs))
2347 connected = 1;
2348 dev_opt = nla_nest_start_noflag(reply, NBD_DEVICE_ITEM);
2349 if (!dev_opt)
2350 return -EMSGSIZE;
2351 ret = nla_put_u32(reply, NBD_DEVICE_INDEX, nbd->index);
2352 if (ret)
2353 return -EMSGSIZE;
2354 ret = nla_put_u8(reply, NBD_DEVICE_CONNECTED,
2355 connected);
2356 if (ret)
2357 return -EMSGSIZE;
2358 nla_nest_end(reply, dev_opt);
2359 return 0;
2360}
2361
2362static int status_cb(int id, void *ptr, void *data)
2363{
2364 struct nbd_device *nbd = ptr;
2365 return populate_nbd_status(nbd, (struct sk_buff *)data);
2366}
2367
2368static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info)
2369{
2370 struct nlattr *dev_list;
2371 struct sk_buff *reply;
2372 void *reply_head;
2373 size_t msg_size;
2374 int index = -1;
2375 int ret = -ENOMEM;
2376
2377 if (info->attrs[NBD_ATTR_INDEX])
2378 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2379
2380 mutex_lock(&nbd_index_mutex);
2381
2382 msg_size = nla_total_size(nla_attr_size(sizeof(u32)) +
2383 nla_attr_size(sizeof(u8)));
2384 msg_size *= (index == -1) ? nbd_total_devices : 1;
2385
2386 reply = genlmsg_new(msg_size, GFP_KERNEL);
2387 if (!reply)
2388 goto out;
2389 reply_head = genlmsg_put_reply(reply, info, &nbd_genl_family, 0,
2390 NBD_CMD_STATUS);
2391 if (!reply_head) {
2392 nlmsg_free(reply);
2393 goto out;
2394 }
2395
2396 dev_list = nla_nest_start_noflag(reply, NBD_ATTR_DEVICE_LIST);
2397 if (index == -1) {
2398 ret = idr_for_each(&nbd_index_idr, &status_cb, reply);
2399 if (ret) {
2400 nlmsg_free(reply);
2401 goto out;
2402 }
2403 } else {
2404 struct nbd_device *nbd;
2405 nbd = idr_find(&nbd_index_idr, index);
2406 if (nbd) {
2407 ret = populate_nbd_status(nbd, reply);
2408 if (ret) {
2409 nlmsg_free(reply);
2410 goto out;
2411 }
2412 }
2413 }
2414 nla_nest_end(reply, dev_list);
2415 genlmsg_end(reply, reply_head);
2416 ret = genlmsg_reply(reply, info);
2417out:
2418 mutex_unlock(&nbd_index_mutex);
2419 return ret;
2420}
2421
2422static void nbd_connect_reply(struct genl_info *info, int index)
2423{
2424 struct sk_buff *skb;
2425 void *msg_head;
2426 int ret;
2427
2428 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2429 if (!skb)
2430 return;
2431 msg_head = genlmsg_put_reply(skb, info, &nbd_genl_family, 0,
2432 NBD_CMD_CONNECT);
2433 if (!msg_head) {
2434 nlmsg_free(skb);
2435 return;
2436 }
2437 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2438 if (ret) {
2439 nlmsg_free(skb);
2440 return;
2441 }
2442 genlmsg_end(skb, msg_head);
2443 genlmsg_reply(skb, info);
2444}
2445
2446static void nbd_mcast_index(int index)
2447{
2448 struct sk_buff *skb;
2449 void *msg_head;
2450 int ret;
2451
2452 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2453 if (!skb)
2454 return;
2455 msg_head = genlmsg_put(skb, 0, 0, &nbd_genl_family, 0,
2456 NBD_CMD_LINK_DEAD);
2457 if (!msg_head) {
2458 nlmsg_free(skb);
2459 return;
2460 }
2461 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2462 if (ret) {
2463 nlmsg_free(skb);
2464 return;
2465 }
2466 genlmsg_end(skb, msg_head);
2467 genlmsg_multicast(&nbd_genl_family, skb, 0, 0, GFP_KERNEL);
2468}
2469
2470static void nbd_dead_link_work(struct work_struct *work)
2471{
2472 struct link_dead_args *args = container_of(work, struct link_dead_args,
2473 work);
2474 nbd_mcast_index(args->index);
2475 kfree(args);
2476}
2477
2478static int __init nbd_init(void)
2479{
2480 int i;
2481
2482 BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
2483
2484 if (max_part < 0) {
2485 pr_err("max_part must be >= 0\n");
2486 return -EINVAL;
2487 }
2488
2489 part_shift = 0;
2490 if (max_part > 0) {
2491 part_shift = fls(max_part);
2492
2493 /*
2494 * Adjust max_part according to part_shift as it is exported
2495 * to user space so that user can know the max number of
2496 * partition kernel should be able to manage.
2497 *
2498 * Note that -1 is required because partition 0 is reserved
2499 * for the whole disk.
2500 */
2501 max_part = (1UL << part_shift) - 1;
2502 }
2503
2504 if ((1UL << part_shift) > DISK_MAX_PARTS)
2505 return -EINVAL;
2506
2507 if (nbds_max > 1UL << (MINORBITS - part_shift))
2508 return -EINVAL;
2509
2510 if (register_blkdev(NBD_MAJOR, "nbd"))
2511 return -EIO;
2512
2513 nbd_del_wq = alloc_workqueue("nbd-del", WQ_UNBOUND, 0);
2514 if (!nbd_del_wq) {
2515 unregister_blkdev(NBD_MAJOR, "nbd");
2516 return -ENOMEM;
2517 }
2518
2519 if (genl_register_family(&nbd_genl_family)) {
2520 destroy_workqueue(nbd_del_wq);
2521 unregister_blkdev(NBD_MAJOR, "nbd");
2522 return -EINVAL;
2523 }
2524 nbd_dbg_init();
2525
2526 for (i = 0; i < nbds_max; i++)
2527 nbd_dev_add(i, 1);
2528 return 0;
2529}
2530
2531static int nbd_exit_cb(int id, void *ptr, void *data)
2532{
2533 struct list_head *list = (struct list_head *)data;
2534 struct nbd_device *nbd = ptr;
2535
2536 /* Skip nbd that is being removed asynchronously */
2537 if (refcount_read(&nbd->refs))
2538 list_add_tail(&nbd->list, list);
2539
2540 return 0;
2541}
2542
2543static void __exit nbd_cleanup(void)
2544{
2545 struct nbd_device *nbd;
2546 LIST_HEAD(del_list);
2547
2548 /*
2549 * Unregister netlink interface prior to waiting
2550 * for the completion of netlink commands.
2551 */
2552 genl_unregister_family(&nbd_genl_family);
2553
2554 nbd_dbg_close();
2555
2556 mutex_lock(&nbd_index_mutex);
2557 idr_for_each(&nbd_index_idr, &nbd_exit_cb, &del_list);
2558 mutex_unlock(&nbd_index_mutex);
2559
2560 while (!list_empty(&del_list)) {
2561 nbd = list_first_entry(&del_list, struct nbd_device, list);
2562 list_del_init(&nbd->list);
2563 if (refcount_read(&nbd->config_refs))
2564 pr_err("possibly leaking nbd_config (ref %d)\n",
2565 refcount_read(&nbd->config_refs));
2566 if (refcount_read(&nbd->refs) != 1)
2567 pr_err("possibly leaking a device\n");
2568 nbd_put(nbd);
2569 }
2570
2571 /* Also wait for nbd_dev_remove_work() completes */
2572 destroy_workqueue(nbd_del_wq);
2573
2574 idr_destroy(&nbd_index_idr);
2575 unregister_blkdev(NBD_MAJOR, "nbd");
2576}
2577
2578module_init(nbd_init);
2579module_exit(nbd_cleanup);
2580
2581MODULE_DESCRIPTION("Network Block Device");
2582MODULE_LICENSE("GPL");
2583
2584module_param(nbds_max, int, 0444);
2585MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
2586module_param(max_part, int, 0444);
2587MODULE_PARM_DESC(max_part, "number of partitions per device (default: 16)");