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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 struct nbd_sock *nsock;
71 int index;
72};
73
74struct link_dead_args {
75 struct work_struct work;
76 int index;
77};
78
79#define NBD_RT_TIMEDOUT 0
80#define NBD_RT_DISCONNECT_REQUESTED 1
81#define NBD_RT_DISCONNECTED 2
82#define NBD_RT_HAS_PID_FILE 3
83#define NBD_RT_HAS_CONFIG_REF 4
84#define NBD_RT_BOUND 5
85#define NBD_RT_DISCONNECT_ON_CLOSE 6
86#define NBD_RT_HAS_BACKEND_FILE 7
87
88#define NBD_DESTROY_ON_DISCONNECT 0
89#define NBD_DISCONNECT_REQUESTED 1
90
91struct nbd_config {
92 u32 flags;
93 unsigned long runtime_flags;
94 u64 dead_conn_timeout;
95
96 struct nbd_sock **socks;
97 int num_connections;
98 atomic_t live_connections;
99 wait_queue_head_t conn_wait;
100
101 atomic_t recv_threads;
102 wait_queue_head_t recv_wq;
103 unsigned int blksize_bits;
104 loff_t bytesize;
105#if IS_ENABLED(CONFIG_DEBUG_FS)
106 struct dentry *dbg_dir;
107#endif
108};
109
110static inline unsigned int nbd_blksize(struct nbd_config *config)
111{
112 return 1u << config->blksize_bits;
113}
114
115struct nbd_device {
116 struct blk_mq_tag_set tag_set;
117
118 int index;
119 refcount_t config_refs;
120 refcount_t refs;
121 struct nbd_config *config;
122 struct mutex config_lock;
123 struct gendisk *disk;
124 struct workqueue_struct *recv_workq;
125 struct work_struct remove_work;
126
127 struct list_head list;
128 struct task_struct *task_setup;
129
130 unsigned long flags;
131 pid_t pid; /* pid of nbd-client, if attached */
132
133 char *backend;
134};
135
136#define NBD_CMD_REQUEUED 1
137/*
138 * This flag will be set if nbd_queue_rq() succeed, and will be checked and
139 * cleared in completion. Both setting and clearing of the flag are protected
140 * by cmd->lock.
141 */
142#define NBD_CMD_INFLIGHT 2
143
144struct nbd_cmd {
145 struct nbd_device *nbd;
146 struct mutex lock;
147 int index;
148 int cookie;
149 int retries;
150 blk_status_t status;
151 unsigned long flags;
152 u32 cmd_cookie;
153};
154
155#if IS_ENABLED(CONFIG_DEBUG_FS)
156static struct dentry *nbd_dbg_dir;
157#endif
158
159#define nbd_name(nbd) ((nbd)->disk->disk_name)
160
161#define NBD_DEF_BLKSIZE_BITS 10
162
163static unsigned int nbds_max = 16;
164static int max_part = 16;
165static int part_shift;
166
167static int nbd_dev_dbg_init(struct nbd_device *nbd);
168static void nbd_dev_dbg_close(struct nbd_device *nbd);
169static void nbd_config_put(struct nbd_device *nbd);
170static void nbd_connect_reply(struct genl_info *info, int index);
171static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info);
172static void nbd_dead_link_work(struct work_struct *work);
173static void nbd_disconnect_and_put(struct nbd_device *nbd);
174
175static inline struct device *nbd_to_dev(struct nbd_device *nbd)
176{
177 return disk_to_dev(nbd->disk);
178}
179
180static void nbd_requeue_cmd(struct nbd_cmd *cmd)
181{
182 struct request *req = blk_mq_rq_from_pdu(cmd);
183
184 if (!test_and_set_bit(NBD_CMD_REQUEUED, &cmd->flags))
185 blk_mq_requeue_request(req, true);
186}
187
188#define NBD_COOKIE_BITS 32
189
190static u64 nbd_cmd_handle(struct nbd_cmd *cmd)
191{
192 struct request *req = blk_mq_rq_from_pdu(cmd);
193 u32 tag = blk_mq_unique_tag(req);
194 u64 cookie = cmd->cmd_cookie;
195
196 return (cookie << NBD_COOKIE_BITS) | tag;
197}
198
199static u32 nbd_handle_to_tag(u64 handle)
200{
201 return (u32)handle;
202}
203
204static u32 nbd_handle_to_cookie(u64 handle)
205{
206 return (u32)(handle >> NBD_COOKIE_BITS);
207}
208
209static const char *nbdcmd_to_ascii(int cmd)
210{
211 switch (cmd) {
212 case NBD_CMD_READ: return "read";
213 case NBD_CMD_WRITE: return "write";
214 case NBD_CMD_DISC: return "disconnect";
215 case NBD_CMD_FLUSH: return "flush";
216 case NBD_CMD_TRIM: return "trim/discard";
217 }
218 return "invalid";
219}
220
221static ssize_t pid_show(struct device *dev,
222 struct device_attribute *attr, char *buf)
223{
224 struct gendisk *disk = dev_to_disk(dev);
225 struct nbd_device *nbd = (struct nbd_device *)disk->private_data;
226
227 return sprintf(buf, "%d\n", nbd->pid);
228}
229
230static const struct device_attribute pid_attr = {
231 .attr = { .name = "pid", .mode = 0444},
232 .show = pid_show,
233};
234
235static ssize_t backend_show(struct device *dev,
236 struct device_attribute *attr, char *buf)
237{
238 struct gendisk *disk = dev_to_disk(dev);
239 struct nbd_device *nbd = (struct nbd_device *)disk->private_data;
240
241 return sprintf(buf, "%s\n", nbd->backend ?: "");
242}
243
244static const struct device_attribute backend_attr = {
245 .attr = { .name = "backend", .mode = 0444},
246 .show = backend_show,
247};
248
249static void nbd_dev_remove(struct nbd_device *nbd)
250{
251 struct gendisk *disk = nbd->disk;
252
253 del_gendisk(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 put_disk(disk);
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 if (bytesize < 0)
329 return -EINVAL;
330
331 nbd->config->bytesize = bytesize;
332 nbd->config->blksize_bits = __ffs(blksize);
333
334 if (!nbd->pid)
335 return 0;
336
337 if (nbd->config->flags & NBD_FLAG_SEND_TRIM)
338 blk_queue_max_discard_sectors(nbd->disk->queue, UINT_MAX);
339 blk_queue_logical_block_size(nbd->disk->queue, blksize);
340 blk_queue_physical_block_size(nbd->disk->queue, blksize);
341
342 if (max_part)
343 set_bit(GD_NEED_PART_SCAN, &nbd->disk->state);
344 if (!set_capacity_and_notify(nbd->disk, bytesize >> 9))
345 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
346 return 0;
347}
348
349static void nbd_complete_rq(struct request *req)
350{
351 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
352
353 dev_dbg(nbd_to_dev(cmd->nbd), "request %p: %s\n", req,
354 cmd->status ? "failed" : "done");
355
356 blk_mq_end_request(req, cmd->status);
357}
358
359/*
360 * Forcibly shutdown the socket causing all listeners to error
361 */
362static void sock_shutdown(struct nbd_device *nbd)
363{
364 struct nbd_config *config = nbd->config;
365 int i;
366
367 if (config->num_connections == 0)
368 return;
369 if (test_and_set_bit(NBD_RT_DISCONNECTED, &config->runtime_flags))
370 return;
371
372 for (i = 0; i < config->num_connections; i++) {
373 struct nbd_sock *nsock = config->socks[i];
374 mutex_lock(&nsock->tx_lock);
375 nbd_mark_nsock_dead(nbd, nsock, 0);
376 mutex_unlock(&nsock->tx_lock);
377 }
378 dev_warn(disk_to_dev(nbd->disk), "shutting down sockets\n");
379}
380
381static u32 req_to_nbd_cmd_type(struct request *req)
382{
383 switch (req_op(req)) {
384 case REQ_OP_DISCARD:
385 return NBD_CMD_TRIM;
386 case REQ_OP_FLUSH:
387 return NBD_CMD_FLUSH;
388 case REQ_OP_WRITE:
389 return NBD_CMD_WRITE;
390 case REQ_OP_READ:
391 return NBD_CMD_READ;
392 default:
393 return U32_MAX;
394 }
395}
396
397static struct nbd_config *nbd_get_config_unlocked(struct nbd_device *nbd)
398{
399 if (refcount_inc_not_zero(&nbd->config_refs)) {
400 /*
401 * Add smp_mb__after_atomic to ensure that reading nbd->config_refs
402 * and reading nbd->config is ordered. The pair is the barrier in
403 * nbd_alloc_and_init_config(), avoid nbd->config_refs is set
404 * before nbd->config.
405 */
406 smp_mb__after_atomic();
407 return nbd->config;
408 }
409
410 return NULL;
411}
412
413static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req)
414{
415 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
416 struct nbd_device *nbd = cmd->nbd;
417 struct nbd_config *config;
418
419 if (!mutex_trylock(&cmd->lock))
420 return BLK_EH_RESET_TIMER;
421
422 if (!test_bit(NBD_CMD_INFLIGHT, &cmd->flags)) {
423 mutex_unlock(&cmd->lock);
424 return BLK_EH_DONE;
425 }
426
427 config = nbd_get_config_unlocked(nbd);
428 if (!config) {
429 cmd->status = BLK_STS_TIMEOUT;
430 __clear_bit(NBD_CMD_INFLIGHT, &cmd->flags);
431 mutex_unlock(&cmd->lock);
432 goto done;
433 }
434
435 if (config->num_connections > 1 ||
436 (config->num_connections == 1 && nbd->tag_set.timeout)) {
437 dev_err_ratelimited(nbd_to_dev(nbd),
438 "Connection timed out, retrying (%d/%d alive)\n",
439 atomic_read(&config->live_connections),
440 config->num_connections);
441 /*
442 * Hooray we have more connections, requeue this IO, the submit
443 * path will put it on a real connection. Or if only one
444 * connection is configured, the submit path will wait util
445 * a new connection is reconfigured or util dead timeout.
446 */
447 if (config->socks) {
448 if (cmd->index < config->num_connections) {
449 struct nbd_sock *nsock =
450 config->socks[cmd->index];
451 mutex_lock(&nsock->tx_lock);
452 /* We can have multiple outstanding requests, so
453 * we don't want to mark the nsock dead if we've
454 * already reconnected with a new socket, so
455 * only mark it dead if its the same socket we
456 * were sent out on.
457 */
458 if (cmd->cookie == nsock->cookie)
459 nbd_mark_nsock_dead(nbd, nsock, 1);
460 mutex_unlock(&nsock->tx_lock);
461 }
462 mutex_unlock(&cmd->lock);
463 nbd_requeue_cmd(cmd);
464 nbd_config_put(nbd);
465 return BLK_EH_DONE;
466 }
467 }
468
469 if (!nbd->tag_set.timeout) {
470 /*
471 * Userspace sets timeout=0 to disable socket disconnection,
472 * so just warn and reset the timer.
473 */
474 struct nbd_sock *nsock = config->socks[cmd->index];
475 cmd->retries++;
476 dev_info(nbd_to_dev(nbd), "Possible stuck request %p: control (%s@%llu,%uB). Runtime %u seconds\n",
477 req, nbdcmd_to_ascii(req_to_nbd_cmd_type(req)),
478 (unsigned long long)blk_rq_pos(req) << 9,
479 blk_rq_bytes(req), (req->timeout / HZ) * cmd->retries);
480
481 mutex_lock(&nsock->tx_lock);
482 if (cmd->cookie != nsock->cookie) {
483 nbd_requeue_cmd(cmd);
484 mutex_unlock(&nsock->tx_lock);
485 mutex_unlock(&cmd->lock);
486 nbd_config_put(nbd);
487 return BLK_EH_DONE;
488 }
489 mutex_unlock(&nsock->tx_lock);
490 mutex_unlock(&cmd->lock);
491 nbd_config_put(nbd);
492 return BLK_EH_RESET_TIMER;
493 }
494
495 dev_err_ratelimited(nbd_to_dev(nbd), "Connection timed out\n");
496 set_bit(NBD_RT_TIMEDOUT, &config->runtime_flags);
497 cmd->status = BLK_STS_IOERR;
498 __clear_bit(NBD_CMD_INFLIGHT, &cmd->flags);
499 mutex_unlock(&cmd->lock);
500 sock_shutdown(nbd);
501 nbd_config_put(nbd);
502done:
503 blk_mq_complete_request(req);
504 return BLK_EH_DONE;
505}
506
507static int __sock_xmit(struct nbd_device *nbd, struct socket *sock, int send,
508 struct iov_iter *iter, int msg_flags, int *sent)
509{
510 int result;
511 struct msghdr msg = {} ;
512 unsigned int noreclaim_flag;
513
514 if (unlikely(!sock)) {
515 dev_err_ratelimited(disk_to_dev(nbd->disk),
516 "Attempted %s on closed socket in sock_xmit\n",
517 (send ? "send" : "recv"));
518 return -EINVAL;
519 }
520
521 msg.msg_iter = *iter;
522
523 noreclaim_flag = memalloc_noreclaim_save();
524 do {
525 sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC;
526 sock->sk->sk_use_task_frag = false;
527 msg.msg_flags = msg_flags | MSG_NOSIGNAL;
528
529 if (send)
530 result = sock_sendmsg(sock, &msg);
531 else
532 result = sock_recvmsg(sock, &msg, msg.msg_flags);
533
534 if (result <= 0) {
535 if (result == 0)
536 result = -EPIPE; /* short read */
537 break;
538 }
539 if (sent)
540 *sent += result;
541 } while (msg_data_left(&msg));
542
543 memalloc_noreclaim_restore(noreclaim_flag);
544
545 return result;
546}
547
548/*
549 * Send or receive packet. Return a positive value on success and
550 * negtive value on failure, and never return 0.
551 */
552static int sock_xmit(struct nbd_device *nbd, int index, int send,
553 struct iov_iter *iter, int msg_flags, int *sent)
554{
555 struct nbd_config *config = nbd->config;
556 struct socket *sock = config->socks[index]->sock;
557
558 return __sock_xmit(nbd, sock, send, iter, msg_flags, sent);
559}
560
561/*
562 * Different settings for sk->sk_sndtimeo can result in different return values
563 * if there is a signal pending when we enter sendmsg, because reasons?
564 */
565static inline int was_interrupted(int result)
566{
567 return result == -ERESTARTSYS || result == -EINTR;
568}
569
570/* always call with the tx_lock held */
571static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
572{
573 struct request *req = blk_mq_rq_from_pdu(cmd);
574 struct nbd_config *config = nbd->config;
575 struct nbd_sock *nsock = config->socks[index];
576 int result;
577 struct nbd_request request = {.magic = htonl(NBD_REQUEST_MAGIC)};
578 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
579 struct iov_iter from;
580 unsigned long size = blk_rq_bytes(req);
581 struct bio *bio;
582 u64 handle;
583 u32 type;
584 u32 nbd_cmd_flags = 0;
585 int sent = nsock->sent, skip = 0;
586
587 iov_iter_kvec(&from, ITER_SOURCE, &iov, 1, sizeof(request));
588
589 type = req_to_nbd_cmd_type(req);
590 if (type == U32_MAX)
591 return -EIO;
592
593 if (rq_data_dir(req) == WRITE &&
594 (config->flags & NBD_FLAG_READ_ONLY)) {
595 dev_err_ratelimited(disk_to_dev(nbd->disk),
596 "Write on read-only\n");
597 return -EIO;
598 }
599
600 if (req->cmd_flags & REQ_FUA)
601 nbd_cmd_flags |= NBD_CMD_FLAG_FUA;
602
603 /* We did a partial send previously, and we at least sent the whole
604 * request struct, so just go and send the rest of the pages in the
605 * request.
606 */
607 if (sent) {
608 if (sent >= sizeof(request)) {
609 skip = sent - sizeof(request);
610
611 /* initialize handle for tracing purposes */
612 handle = nbd_cmd_handle(cmd);
613
614 goto send_pages;
615 }
616 iov_iter_advance(&from, sent);
617 } else {
618 cmd->cmd_cookie++;
619 }
620 cmd->index = index;
621 cmd->cookie = nsock->cookie;
622 cmd->retries = 0;
623 request.type = htonl(type | nbd_cmd_flags);
624 if (type != NBD_CMD_FLUSH) {
625 request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
626 request.len = htonl(size);
627 }
628 handle = nbd_cmd_handle(cmd);
629 request.cookie = cpu_to_be64(handle);
630
631 trace_nbd_send_request(&request, nbd->index, blk_mq_rq_from_pdu(cmd));
632
633 dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n",
634 req, nbdcmd_to_ascii(type),
635 (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req));
636 result = sock_xmit(nbd, index, 1, &from,
637 (type == NBD_CMD_WRITE) ? MSG_MORE : 0, &sent);
638 trace_nbd_header_sent(req, handle);
639 if (result < 0) {
640 if (was_interrupted(result)) {
641 /* If we haven't sent anything we can just return BUSY,
642 * however if we have sent something we need to make
643 * sure we only allow this req to be sent until we are
644 * completely done.
645 */
646 if (sent) {
647 nsock->pending = req;
648 nsock->sent = sent;
649 }
650 set_bit(NBD_CMD_REQUEUED, &cmd->flags);
651 return BLK_STS_RESOURCE;
652 }
653 dev_err_ratelimited(disk_to_dev(nbd->disk),
654 "Send control failed (result %d)\n", result);
655 return -EAGAIN;
656 }
657send_pages:
658 if (type != NBD_CMD_WRITE)
659 goto out;
660
661 bio = req->bio;
662 while (bio) {
663 struct bio *next = bio->bi_next;
664 struct bvec_iter iter;
665 struct bio_vec bvec;
666
667 bio_for_each_segment(bvec, bio, iter) {
668 bool is_last = !next && bio_iter_last(bvec, iter);
669 int flags = is_last ? 0 : MSG_MORE;
670
671 dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n",
672 req, bvec.bv_len);
673 iov_iter_bvec(&from, ITER_SOURCE, &bvec, 1, bvec.bv_len);
674 if (skip) {
675 if (skip >= iov_iter_count(&from)) {
676 skip -= iov_iter_count(&from);
677 continue;
678 }
679 iov_iter_advance(&from, skip);
680 skip = 0;
681 }
682 result = sock_xmit(nbd, index, 1, &from, flags, &sent);
683 if (result < 0) {
684 if (was_interrupted(result)) {
685 /* We've already sent the header, we
686 * have no choice but to set pending and
687 * return BUSY.
688 */
689 nsock->pending = req;
690 nsock->sent = sent;
691 set_bit(NBD_CMD_REQUEUED, &cmd->flags);
692 return BLK_STS_RESOURCE;
693 }
694 dev_err(disk_to_dev(nbd->disk),
695 "Send data failed (result %d)\n",
696 result);
697 return -EAGAIN;
698 }
699 /*
700 * The completion might already have come in,
701 * so break for the last one instead of letting
702 * the iterator do it. This prevents use-after-free
703 * of the bio.
704 */
705 if (is_last)
706 break;
707 }
708 bio = next;
709 }
710out:
711 trace_nbd_payload_sent(req, handle);
712 nsock->pending = NULL;
713 nsock->sent = 0;
714 return 0;
715}
716
717static int nbd_read_reply(struct nbd_device *nbd, struct socket *sock,
718 struct nbd_reply *reply)
719{
720 struct kvec iov = {.iov_base = reply, .iov_len = sizeof(*reply)};
721 struct iov_iter to;
722 int result;
723
724 reply->magic = 0;
725 iov_iter_kvec(&to, ITER_DEST, &iov, 1, sizeof(*reply));
726 result = __sock_xmit(nbd, sock, 0, &to, MSG_WAITALL, NULL);
727 if (result < 0) {
728 if (!nbd_disconnected(nbd->config))
729 dev_err(disk_to_dev(nbd->disk),
730 "Receive control failed (result %d)\n", result);
731 return result;
732 }
733
734 if (ntohl(reply->magic) != NBD_REPLY_MAGIC) {
735 dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n",
736 (unsigned long)ntohl(reply->magic));
737 return -EPROTO;
738 }
739
740 return 0;
741}
742
743/* NULL returned = something went wrong, inform userspace */
744static struct nbd_cmd *nbd_handle_reply(struct nbd_device *nbd, int index,
745 struct nbd_reply *reply)
746{
747 int result;
748 struct nbd_cmd *cmd;
749 struct request *req = NULL;
750 u64 handle;
751 u16 hwq;
752 u32 tag;
753 int ret = 0;
754
755 handle = be64_to_cpu(reply->cookie);
756 tag = nbd_handle_to_tag(handle);
757 hwq = blk_mq_unique_tag_to_hwq(tag);
758 if (hwq < nbd->tag_set.nr_hw_queues)
759 req = blk_mq_tag_to_rq(nbd->tag_set.tags[hwq],
760 blk_mq_unique_tag_to_tag(tag));
761 if (!req || !blk_mq_request_started(req)) {
762 dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%d) %p\n",
763 tag, req);
764 return ERR_PTR(-ENOENT);
765 }
766 trace_nbd_header_received(req, handle);
767 cmd = blk_mq_rq_to_pdu(req);
768
769 mutex_lock(&cmd->lock);
770 if (!test_bit(NBD_CMD_INFLIGHT, &cmd->flags)) {
771 dev_err(disk_to_dev(nbd->disk), "Suspicious reply %d (status %u flags %lu)",
772 tag, cmd->status, cmd->flags);
773 ret = -ENOENT;
774 goto out;
775 }
776 if (cmd->index != index) {
777 dev_err(disk_to_dev(nbd->disk), "Unexpected reply %d from different sock %d (expected %d)",
778 tag, index, cmd->index);
779 ret = -ENOENT;
780 goto out;
781 }
782 if (cmd->cmd_cookie != nbd_handle_to_cookie(handle)) {
783 dev_err(disk_to_dev(nbd->disk), "Double reply on req %p, cmd_cookie %u, handle cookie %u\n",
784 req, cmd->cmd_cookie, nbd_handle_to_cookie(handle));
785 ret = -ENOENT;
786 goto out;
787 }
788 if (cmd->status != BLK_STS_OK) {
789 dev_err(disk_to_dev(nbd->disk), "Command already handled %p\n",
790 req);
791 ret = -ENOENT;
792 goto out;
793 }
794 if (test_bit(NBD_CMD_REQUEUED, &cmd->flags)) {
795 dev_err(disk_to_dev(nbd->disk), "Raced with timeout on req %p\n",
796 req);
797 ret = -ENOENT;
798 goto out;
799 }
800 if (ntohl(reply->error)) {
801 dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n",
802 ntohl(reply->error));
803 cmd->status = BLK_STS_IOERR;
804 goto out;
805 }
806
807 dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", req);
808 if (rq_data_dir(req) != WRITE) {
809 struct req_iterator iter;
810 struct bio_vec bvec;
811 struct iov_iter to;
812
813 rq_for_each_segment(bvec, req, iter) {
814 iov_iter_bvec(&to, ITER_DEST, &bvec, 1, bvec.bv_len);
815 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
816 if (result < 0) {
817 dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
818 result);
819 /*
820 * If we've disconnected, we need to make sure we
821 * complete this request, otherwise error out
822 * and let the timeout stuff handle resubmitting
823 * this request onto another connection.
824 */
825 if (nbd_disconnected(nbd->config)) {
826 cmd->status = BLK_STS_IOERR;
827 goto out;
828 }
829 ret = -EIO;
830 goto out;
831 }
832 dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n",
833 req, bvec.bv_len);
834 }
835 }
836out:
837 trace_nbd_payload_received(req, handle);
838 mutex_unlock(&cmd->lock);
839 return ret ? ERR_PTR(ret) : cmd;
840}
841
842static void recv_work(struct work_struct *work)
843{
844 struct recv_thread_args *args = container_of(work,
845 struct recv_thread_args,
846 work);
847 struct nbd_device *nbd = args->nbd;
848 struct nbd_config *config = nbd->config;
849 struct request_queue *q = nbd->disk->queue;
850 struct nbd_sock *nsock = args->nsock;
851 struct nbd_cmd *cmd;
852 struct request *rq;
853
854 while (1) {
855 struct nbd_reply reply;
856
857 if (nbd_read_reply(nbd, nsock->sock, &reply))
858 break;
859
860 /*
861 * Grab .q_usage_counter so request pool won't go away, then no
862 * request use-after-free is possible during nbd_handle_reply().
863 * If queue is frozen, there won't be any inflight requests, we
864 * needn't to handle the incoming garbage message.
865 */
866 if (!percpu_ref_tryget(&q->q_usage_counter)) {
867 dev_err(disk_to_dev(nbd->disk), "%s: no io inflight\n",
868 __func__);
869 break;
870 }
871
872 cmd = nbd_handle_reply(nbd, args->index, &reply);
873 if (IS_ERR(cmd)) {
874 percpu_ref_put(&q->q_usage_counter);
875 break;
876 }
877
878 rq = blk_mq_rq_from_pdu(cmd);
879 if (likely(!blk_should_fake_timeout(rq->q))) {
880 bool complete;
881
882 mutex_lock(&cmd->lock);
883 complete = __test_and_clear_bit(NBD_CMD_INFLIGHT,
884 &cmd->flags);
885 mutex_unlock(&cmd->lock);
886 if (complete)
887 blk_mq_complete_request(rq);
888 }
889 percpu_ref_put(&q->q_usage_counter);
890 }
891
892 mutex_lock(&nsock->tx_lock);
893 nbd_mark_nsock_dead(nbd, nsock, 1);
894 mutex_unlock(&nsock->tx_lock);
895
896 nbd_config_put(nbd);
897 atomic_dec(&config->recv_threads);
898 wake_up(&config->recv_wq);
899 kfree(args);
900}
901
902static bool nbd_clear_req(struct request *req, void *data)
903{
904 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
905
906 /* don't abort one completed request */
907 if (blk_mq_request_completed(req))
908 return true;
909
910 mutex_lock(&cmd->lock);
911 if (!__test_and_clear_bit(NBD_CMD_INFLIGHT, &cmd->flags)) {
912 mutex_unlock(&cmd->lock);
913 return true;
914 }
915 cmd->status = BLK_STS_IOERR;
916 mutex_unlock(&cmd->lock);
917
918 blk_mq_complete_request(req);
919 return true;
920}
921
922static void nbd_clear_que(struct nbd_device *nbd)
923{
924 blk_mq_quiesce_queue(nbd->disk->queue);
925 blk_mq_tagset_busy_iter(&nbd->tag_set, nbd_clear_req, NULL);
926 blk_mq_unquiesce_queue(nbd->disk->queue);
927 dev_dbg(disk_to_dev(nbd->disk), "queue cleared\n");
928}
929
930static int find_fallback(struct nbd_device *nbd, int index)
931{
932 struct nbd_config *config = nbd->config;
933 int new_index = -1;
934 struct nbd_sock *nsock = config->socks[index];
935 int fallback = nsock->fallback_index;
936
937 if (test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags))
938 return new_index;
939
940 if (config->num_connections <= 1) {
941 dev_err_ratelimited(disk_to_dev(nbd->disk),
942 "Dead connection, failed to find a fallback\n");
943 return new_index;
944 }
945
946 if (fallback >= 0 && fallback < config->num_connections &&
947 !config->socks[fallback]->dead)
948 return fallback;
949
950 if (nsock->fallback_index < 0 ||
951 nsock->fallback_index >= config->num_connections ||
952 config->socks[nsock->fallback_index]->dead) {
953 int i;
954 for (i = 0; i < config->num_connections; i++) {
955 if (i == index)
956 continue;
957 if (!config->socks[i]->dead) {
958 new_index = i;
959 break;
960 }
961 }
962 nsock->fallback_index = new_index;
963 if (new_index < 0) {
964 dev_err_ratelimited(disk_to_dev(nbd->disk),
965 "Dead connection, failed to find a fallback\n");
966 return new_index;
967 }
968 }
969 new_index = nsock->fallback_index;
970 return new_index;
971}
972
973static int wait_for_reconnect(struct nbd_device *nbd)
974{
975 struct nbd_config *config = nbd->config;
976 if (!config->dead_conn_timeout)
977 return 0;
978
979 if (!wait_event_timeout(config->conn_wait,
980 test_bit(NBD_RT_DISCONNECTED,
981 &config->runtime_flags) ||
982 atomic_read(&config->live_connections) > 0,
983 config->dead_conn_timeout))
984 return 0;
985
986 return !test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags);
987}
988
989static int nbd_handle_cmd(struct nbd_cmd *cmd, int index)
990{
991 struct request *req = blk_mq_rq_from_pdu(cmd);
992 struct nbd_device *nbd = cmd->nbd;
993 struct nbd_config *config;
994 struct nbd_sock *nsock;
995 int ret;
996
997 config = nbd_get_config_unlocked(nbd);
998 if (!config) {
999 dev_err_ratelimited(disk_to_dev(nbd->disk),
1000 "Socks array is empty\n");
1001 return -EINVAL;
1002 }
1003
1004 if (index >= config->num_connections) {
1005 dev_err_ratelimited(disk_to_dev(nbd->disk),
1006 "Attempted send on invalid socket\n");
1007 nbd_config_put(nbd);
1008 return -EINVAL;
1009 }
1010 cmd->status = BLK_STS_OK;
1011again:
1012 nsock = config->socks[index];
1013 mutex_lock(&nsock->tx_lock);
1014 if (nsock->dead) {
1015 int old_index = index;
1016 index = find_fallback(nbd, index);
1017 mutex_unlock(&nsock->tx_lock);
1018 if (index < 0) {
1019 if (wait_for_reconnect(nbd)) {
1020 index = old_index;
1021 goto again;
1022 }
1023 /* All the sockets should already be down at this point,
1024 * we just want to make sure that DISCONNECTED is set so
1025 * any requests that come in that were queue'ed waiting
1026 * for the reconnect timer don't trigger the timer again
1027 * and instead just error out.
1028 */
1029 sock_shutdown(nbd);
1030 nbd_config_put(nbd);
1031 return -EIO;
1032 }
1033 goto again;
1034 }
1035
1036 /* Handle the case that we have a pending request that was partially
1037 * transmitted that _has_ to be serviced first. We need to call requeue
1038 * here so that it gets put _after_ the request that is already on the
1039 * dispatch list.
1040 */
1041 blk_mq_start_request(req);
1042 if (unlikely(nsock->pending && nsock->pending != req)) {
1043 nbd_requeue_cmd(cmd);
1044 ret = 0;
1045 goto out;
1046 }
1047 /*
1048 * Some failures are related to the link going down, so anything that
1049 * returns EAGAIN can be retried on a different socket.
1050 */
1051 ret = nbd_send_cmd(nbd, cmd, index);
1052 /*
1053 * Access to this flag is protected by cmd->lock, thus it's safe to set
1054 * the flag after nbd_send_cmd() succeed to send request to server.
1055 */
1056 if (!ret)
1057 __set_bit(NBD_CMD_INFLIGHT, &cmd->flags);
1058 else if (ret == -EAGAIN) {
1059 dev_err_ratelimited(disk_to_dev(nbd->disk),
1060 "Request send failed, requeueing\n");
1061 nbd_mark_nsock_dead(nbd, nsock, 1);
1062 nbd_requeue_cmd(cmd);
1063 ret = 0;
1064 }
1065out:
1066 mutex_unlock(&nsock->tx_lock);
1067 nbd_config_put(nbd);
1068 return ret;
1069}
1070
1071static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
1072 const struct blk_mq_queue_data *bd)
1073{
1074 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
1075 int ret;
1076
1077 /*
1078 * Since we look at the bio's to send the request over the network we
1079 * need to make sure the completion work doesn't mark this request done
1080 * before we are done doing our send. This keeps us from dereferencing
1081 * freed data if we have particularly fast completions (ie we get the
1082 * completion before we exit sock_xmit on the last bvec) or in the case
1083 * that the server is misbehaving (or there was an error) before we're
1084 * done sending everything over the wire.
1085 */
1086 mutex_lock(&cmd->lock);
1087 clear_bit(NBD_CMD_REQUEUED, &cmd->flags);
1088
1089 /* We can be called directly from the user space process, which means we
1090 * could possibly have signals pending so our sendmsg will fail. In
1091 * this case we need to return that we are busy, otherwise error out as
1092 * appropriate.
1093 */
1094 ret = nbd_handle_cmd(cmd, hctx->queue_num);
1095 if (ret < 0)
1096 ret = BLK_STS_IOERR;
1097 else if (!ret)
1098 ret = BLK_STS_OK;
1099 mutex_unlock(&cmd->lock);
1100
1101 return ret;
1102}
1103
1104static struct socket *nbd_get_socket(struct nbd_device *nbd, unsigned long fd,
1105 int *err)
1106{
1107 struct socket *sock;
1108
1109 *err = 0;
1110 sock = sockfd_lookup(fd, err);
1111 if (!sock)
1112 return NULL;
1113
1114 if (sock->ops->shutdown == sock_no_shutdown) {
1115 dev_err(disk_to_dev(nbd->disk), "Unsupported socket: shutdown callout must be supported.\n");
1116 *err = -EINVAL;
1117 sockfd_put(sock);
1118 return NULL;
1119 }
1120
1121 return sock;
1122}
1123
1124static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
1125 bool netlink)
1126{
1127 struct nbd_config *config = nbd->config;
1128 struct socket *sock;
1129 struct nbd_sock **socks;
1130 struct nbd_sock *nsock;
1131 int err;
1132
1133 /* Arg will be cast to int, check it to avoid overflow */
1134 if (arg > INT_MAX)
1135 return -EINVAL;
1136 sock = nbd_get_socket(nbd, arg, &err);
1137 if (!sock)
1138 return err;
1139
1140 /*
1141 * We need to make sure we don't get any errant requests while we're
1142 * reallocating the ->socks array.
1143 */
1144 blk_mq_freeze_queue(nbd->disk->queue);
1145
1146 if (!netlink && !nbd->task_setup &&
1147 !test_bit(NBD_RT_BOUND, &config->runtime_flags))
1148 nbd->task_setup = current;
1149
1150 if (!netlink &&
1151 (nbd->task_setup != current ||
1152 test_bit(NBD_RT_BOUND, &config->runtime_flags))) {
1153 dev_err(disk_to_dev(nbd->disk),
1154 "Device being setup by another task");
1155 err = -EBUSY;
1156 goto put_socket;
1157 }
1158
1159 nsock = kzalloc(sizeof(*nsock), GFP_KERNEL);
1160 if (!nsock) {
1161 err = -ENOMEM;
1162 goto put_socket;
1163 }
1164
1165 socks = krealloc(config->socks, (config->num_connections + 1) *
1166 sizeof(struct nbd_sock *), GFP_KERNEL);
1167 if (!socks) {
1168 kfree(nsock);
1169 err = -ENOMEM;
1170 goto put_socket;
1171 }
1172
1173 config->socks = socks;
1174
1175 nsock->fallback_index = -1;
1176 nsock->dead = false;
1177 mutex_init(&nsock->tx_lock);
1178 nsock->sock = sock;
1179 nsock->pending = NULL;
1180 nsock->sent = 0;
1181 nsock->cookie = 0;
1182 socks[config->num_connections++] = nsock;
1183 atomic_inc(&config->live_connections);
1184 blk_mq_unfreeze_queue(nbd->disk->queue);
1185
1186 return 0;
1187
1188put_socket:
1189 blk_mq_unfreeze_queue(nbd->disk->queue);
1190 sockfd_put(sock);
1191 return err;
1192}
1193
1194static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg)
1195{
1196 struct nbd_config *config = nbd->config;
1197 struct socket *sock, *old;
1198 struct recv_thread_args *args;
1199 int i;
1200 int err;
1201
1202 sock = nbd_get_socket(nbd, arg, &err);
1203 if (!sock)
1204 return err;
1205
1206 args = kzalloc(sizeof(*args), GFP_KERNEL);
1207 if (!args) {
1208 sockfd_put(sock);
1209 return -ENOMEM;
1210 }
1211
1212 for (i = 0; i < config->num_connections; i++) {
1213 struct nbd_sock *nsock = config->socks[i];
1214
1215 if (!nsock->dead)
1216 continue;
1217
1218 mutex_lock(&nsock->tx_lock);
1219 if (!nsock->dead) {
1220 mutex_unlock(&nsock->tx_lock);
1221 continue;
1222 }
1223 sk_set_memalloc(sock->sk);
1224 if (nbd->tag_set.timeout)
1225 sock->sk->sk_sndtimeo = nbd->tag_set.timeout;
1226 atomic_inc(&config->recv_threads);
1227 refcount_inc(&nbd->config_refs);
1228 old = nsock->sock;
1229 nsock->fallback_index = -1;
1230 nsock->sock = sock;
1231 nsock->dead = false;
1232 INIT_WORK(&args->work, recv_work);
1233 args->index = i;
1234 args->nbd = nbd;
1235 args->nsock = nsock;
1236 nsock->cookie++;
1237 mutex_unlock(&nsock->tx_lock);
1238 sockfd_put(old);
1239
1240 clear_bit(NBD_RT_DISCONNECTED, &config->runtime_flags);
1241
1242 /* We take the tx_mutex in an error path in the recv_work, so we
1243 * need to queue_work outside of the tx_mutex.
1244 */
1245 queue_work(nbd->recv_workq, &args->work);
1246
1247 atomic_inc(&config->live_connections);
1248 wake_up(&config->conn_wait);
1249 return 0;
1250 }
1251 sockfd_put(sock);
1252 kfree(args);
1253 return -ENOSPC;
1254}
1255
1256static void nbd_bdev_reset(struct nbd_device *nbd)
1257{
1258 if (disk_openers(nbd->disk) > 1)
1259 return;
1260 set_capacity(nbd->disk, 0);
1261}
1262
1263static void nbd_parse_flags(struct nbd_device *nbd)
1264{
1265 struct nbd_config *config = nbd->config;
1266 if (config->flags & NBD_FLAG_READ_ONLY)
1267 set_disk_ro(nbd->disk, true);
1268 else
1269 set_disk_ro(nbd->disk, false);
1270 if (config->flags & NBD_FLAG_SEND_FLUSH) {
1271 if (config->flags & NBD_FLAG_SEND_FUA)
1272 blk_queue_write_cache(nbd->disk->queue, true, true);
1273 else
1274 blk_queue_write_cache(nbd->disk->queue, true, false);
1275 }
1276 else
1277 blk_queue_write_cache(nbd->disk->queue, false, false);
1278}
1279
1280static void send_disconnects(struct nbd_device *nbd)
1281{
1282 struct nbd_config *config = nbd->config;
1283 struct nbd_request request = {
1284 .magic = htonl(NBD_REQUEST_MAGIC),
1285 .type = htonl(NBD_CMD_DISC),
1286 };
1287 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
1288 struct iov_iter from;
1289 int i, ret;
1290
1291 for (i = 0; i < config->num_connections; i++) {
1292 struct nbd_sock *nsock = config->socks[i];
1293
1294 iov_iter_kvec(&from, ITER_SOURCE, &iov, 1, sizeof(request));
1295 mutex_lock(&nsock->tx_lock);
1296 ret = sock_xmit(nbd, i, 1, &from, 0, NULL);
1297 if (ret < 0)
1298 dev_err(disk_to_dev(nbd->disk),
1299 "Send disconnect failed %d\n", ret);
1300 mutex_unlock(&nsock->tx_lock);
1301 }
1302}
1303
1304static int nbd_disconnect(struct nbd_device *nbd)
1305{
1306 struct nbd_config *config = nbd->config;
1307
1308 dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
1309 set_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags);
1310 set_bit(NBD_DISCONNECT_REQUESTED, &nbd->flags);
1311 send_disconnects(nbd);
1312 return 0;
1313}
1314
1315static void nbd_clear_sock(struct nbd_device *nbd)
1316{
1317 sock_shutdown(nbd);
1318 nbd_clear_que(nbd);
1319 nbd->task_setup = NULL;
1320}
1321
1322static void nbd_config_put(struct nbd_device *nbd)
1323{
1324 if (refcount_dec_and_mutex_lock(&nbd->config_refs,
1325 &nbd->config_lock)) {
1326 struct nbd_config *config = nbd->config;
1327 nbd_dev_dbg_close(nbd);
1328 invalidate_disk(nbd->disk);
1329 if (nbd->config->bytesize)
1330 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
1331 if (test_and_clear_bit(NBD_RT_HAS_PID_FILE,
1332 &config->runtime_flags))
1333 device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
1334 nbd->pid = 0;
1335 if (test_and_clear_bit(NBD_RT_HAS_BACKEND_FILE,
1336 &config->runtime_flags)) {
1337 device_remove_file(disk_to_dev(nbd->disk), &backend_attr);
1338 kfree(nbd->backend);
1339 nbd->backend = NULL;
1340 }
1341 nbd_clear_sock(nbd);
1342 if (config->num_connections) {
1343 int i;
1344 for (i = 0; i < config->num_connections; i++) {
1345 sockfd_put(config->socks[i]->sock);
1346 kfree(config->socks[i]);
1347 }
1348 kfree(config->socks);
1349 }
1350 kfree(nbd->config);
1351 nbd->config = NULL;
1352
1353 nbd->tag_set.timeout = 0;
1354 blk_queue_max_discard_sectors(nbd->disk->queue, 0);
1355
1356 mutex_unlock(&nbd->config_lock);
1357 nbd_put(nbd);
1358 module_put(THIS_MODULE);
1359 }
1360}
1361
1362static int nbd_start_device(struct nbd_device *nbd)
1363{
1364 struct nbd_config *config = nbd->config;
1365 int num_connections = config->num_connections;
1366 int error = 0, i;
1367
1368 if (nbd->pid)
1369 return -EBUSY;
1370 if (!config->socks)
1371 return -EINVAL;
1372 if (num_connections > 1 &&
1373 !(config->flags & NBD_FLAG_CAN_MULTI_CONN)) {
1374 dev_err(disk_to_dev(nbd->disk), "server does not support multiple connections per device.\n");
1375 return -EINVAL;
1376 }
1377
1378 blk_mq_update_nr_hw_queues(&nbd->tag_set, config->num_connections);
1379 nbd->pid = task_pid_nr(current);
1380
1381 nbd_parse_flags(nbd);
1382
1383 error = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
1384 if (error) {
1385 dev_err(disk_to_dev(nbd->disk), "device_create_file failed for pid!\n");
1386 return error;
1387 }
1388 set_bit(NBD_RT_HAS_PID_FILE, &config->runtime_flags);
1389
1390 nbd_dev_dbg_init(nbd);
1391 for (i = 0; i < num_connections; i++) {
1392 struct recv_thread_args *args;
1393
1394 args = kzalloc(sizeof(*args), GFP_KERNEL);
1395 if (!args) {
1396 sock_shutdown(nbd);
1397 /*
1398 * If num_connections is m (2 < m),
1399 * and NO.1 ~ NO.n(1 < n < m) kzallocs are successful.
1400 * But NO.(n + 1) failed. We still have n recv threads.
1401 * So, add flush_workqueue here to prevent recv threads
1402 * dropping the last config_refs and trying to destroy
1403 * the workqueue from inside the workqueue.
1404 */
1405 if (i)
1406 flush_workqueue(nbd->recv_workq);
1407 return -ENOMEM;
1408 }
1409 sk_set_memalloc(config->socks[i]->sock->sk);
1410 if (nbd->tag_set.timeout)
1411 config->socks[i]->sock->sk->sk_sndtimeo =
1412 nbd->tag_set.timeout;
1413 atomic_inc(&config->recv_threads);
1414 refcount_inc(&nbd->config_refs);
1415 INIT_WORK(&args->work, recv_work);
1416 args->nbd = nbd;
1417 args->nsock = config->socks[i];
1418 args->index = i;
1419 queue_work(nbd->recv_workq, &args->work);
1420 }
1421 return nbd_set_size(nbd, config->bytesize, nbd_blksize(config));
1422}
1423
1424static int nbd_start_device_ioctl(struct nbd_device *nbd)
1425{
1426 struct nbd_config *config = nbd->config;
1427 int ret;
1428
1429 ret = nbd_start_device(nbd);
1430 if (ret)
1431 return ret;
1432
1433 if (max_part)
1434 set_bit(GD_NEED_PART_SCAN, &nbd->disk->state);
1435 mutex_unlock(&nbd->config_lock);
1436 ret = wait_event_interruptible(config->recv_wq,
1437 atomic_read(&config->recv_threads) == 0);
1438 if (ret) {
1439 sock_shutdown(nbd);
1440 nbd_clear_que(nbd);
1441 }
1442
1443 flush_workqueue(nbd->recv_workq);
1444 mutex_lock(&nbd->config_lock);
1445 nbd_bdev_reset(nbd);
1446 /* user requested, ignore socket errors */
1447 if (test_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags))
1448 ret = 0;
1449 if (test_bit(NBD_RT_TIMEDOUT, &config->runtime_flags))
1450 ret = -ETIMEDOUT;
1451 return ret;
1452}
1453
1454static void nbd_clear_sock_ioctl(struct nbd_device *nbd)
1455{
1456 nbd_clear_sock(nbd);
1457 disk_force_media_change(nbd->disk);
1458 nbd_bdev_reset(nbd);
1459 if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF,
1460 &nbd->config->runtime_flags))
1461 nbd_config_put(nbd);
1462}
1463
1464static void nbd_set_cmd_timeout(struct nbd_device *nbd, u64 timeout)
1465{
1466 nbd->tag_set.timeout = timeout * HZ;
1467 if (timeout)
1468 blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ);
1469 else
1470 blk_queue_rq_timeout(nbd->disk->queue, 30 * HZ);
1471}
1472
1473/* Must be called with config_lock held */
1474static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
1475 unsigned int cmd, unsigned long arg)
1476{
1477 struct nbd_config *config = nbd->config;
1478 loff_t bytesize;
1479
1480 switch (cmd) {
1481 case NBD_DISCONNECT:
1482 return nbd_disconnect(nbd);
1483 case NBD_CLEAR_SOCK:
1484 nbd_clear_sock_ioctl(nbd);
1485 return 0;
1486 case NBD_SET_SOCK:
1487 return nbd_add_socket(nbd, arg, false);
1488 case NBD_SET_BLKSIZE:
1489 return nbd_set_size(nbd, config->bytesize, arg);
1490 case NBD_SET_SIZE:
1491 return nbd_set_size(nbd, arg, nbd_blksize(config));
1492 case NBD_SET_SIZE_BLOCKS:
1493 if (check_shl_overflow(arg, config->blksize_bits, &bytesize))
1494 return -EINVAL;
1495 return nbd_set_size(nbd, bytesize, nbd_blksize(config));
1496 case NBD_SET_TIMEOUT:
1497 nbd_set_cmd_timeout(nbd, arg);
1498 return 0;
1499
1500 case NBD_SET_FLAGS:
1501 config->flags = arg;
1502 return 0;
1503 case NBD_DO_IT:
1504 return nbd_start_device_ioctl(nbd);
1505 case NBD_CLEAR_QUE:
1506 /*
1507 * This is for compatibility only. The queue is always cleared
1508 * by NBD_DO_IT or NBD_CLEAR_SOCK.
1509 */
1510 return 0;
1511 case NBD_PRINT_DEBUG:
1512 /*
1513 * For compatibility only, we no longer keep a list of
1514 * outstanding requests.
1515 */
1516 return 0;
1517 }
1518 return -ENOTTY;
1519}
1520
1521static int nbd_ioctl(struct block_device *bdev, blk_mode_t mode,
1522 unsigned int cmd, unsigned long arg)
1523{
1524 struct nbd_device *nbd = bdev->bd_disk->private_data;
1525 struct nbd_config *config = nbd->config;
1526 int error = -EINVAL;
1527
1528 if (!capable(CAP_SYS_ADMIN))
1529 return -EPERM;
1530
1531 /* The block layer will pass back some non-nbd ioctls in case we have
1532 * special handling for them, but we don't so just return an error.
1533 */
1534 if (_IOC_TYPE(cmd) != 0xab)
1535 return -EINVAL;
1536
1537 mutex_lock(&nbd->config_lock);
1538
1539 /* Don't allow ioctl operations on a nbd device that was created with
1540 * netlink, unless it's DISCONNECT or CLEAR_SOCK, which are fine.
1541 */
1542 if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) ||
1543 (cmd == NBD_DISCONNECT || cmd == NBD_CLEAR_SOCK))
1544 error = __nbd_ioctl(bdev, nbd, cmd, arg);
1545 else
1546 dev_err(nbd_to_dev(nbd), "Cannot use ioctl interface on a netlink controlled device.\n");
1547 mutex_unlock(&nbd->config_lock);
1548 return error;
1549}
1550
1551static int nbd_alloc_and_init_config(struct nbd_device *nbd)
1552{
1553 struct nbd_config *config;
1554
1555 if (WARN_ON(nbd->config))
1556 return -EINVAL;
1557
1558 if (!try_module_get(THIS_MODULE))
1559 return -ENODEV;
1560
1561 config = kzalloc(sizeof(struct nbd_config), GFP_NOFS);
1562 if (!config) {
1563 module_put(THIS_MODULE);
1564 return -ENOMEM;
1565 }
1566
1567 atomic_set(&config->recv_threads, 0);
1568 init_waitqueue_head(&config->recv_wq);
1569 init_waitqueue_head(&config->conn_wait);
1570 config->blksize_bits = NBD_DEF_BLKSIZE_BITS;
1571 atomic_set(&config->live_connections, 0);
1572
1573 nbd->config = config;
1574 /*
1575 * Order refcount_set(&nbd->config_refs, 1) and nbd->config assignment,
1576 * its pair is the barrier in nbd_get_config_unlocked().
1577 * So nbd_get_config_unlocked() won't see nbd->config as null after
1578 * refcount_inc_not_zero() succeed.
1579 */
1580 smp_mb__before_atomic();
1581 refcount_set(&nbd->config_refs, 1);
1582
1583 return 0;
1584}
1585
1586static int nbd_open(struct gendisk *disk, blk_mode_t mode)
1587{
1588 struct nbd_device *nbd;
1589 struct nbd_config *config;
1590 int ret = 0;
1591
1592 mutex_lock(&nbd_index_mutex);
1593 nbd = disk->private_data;
1594 if (!nbd) {
1595 ret = -ENXIO;
1596 goto out;
1597 }
1598 if (!refcount_inc_not_zero(&nbd->refs)) {
1599 ret = -ENXIO;
1600 goto out;
1601 }
1602
1603 config = nbd_get_config_unlocked(nbd);
1604 if (!config) {
1605 mutex_lock(&nbd->config_lock);
1606 if (refcount_inc_not_zero(&nbd->config_refs)) {
1607 mutex_unlock(&nbd->config_lock);
1608 goto out;
1609 }
1610 ret = nbd_alloc_and_init_config(nbd);
1611 if (ret) {
1612 mutex_unlock(&nbd->config_lock);
1613 goto out;
1614 }
1615
1616 refcount_inc(&nbd->refs);
1617 mutex_unlock(&nbd->config_lock);
1618 if (max_part)
1619 set_bit(GD_NEED_PART_SCAN, &disk->state);
1620 } else if (nbd_disconnected(config)) {
1621 if (max_part)
1622 set_bit(GD_NEED_PART_SCAN, &disk->state);
1623 }
1624out:
1625 mutex_unlock(&nbd_index_mutex);
1626 return ret;
1627}
1628
1629static void nbd_release(struct gendisk *disk)
1630{
1631 struct nbd_device *nbd = disk->private_data;
1632
1633 if (test_bit(NBD_RT_DISCONNECT_ON_CLOSE, &nbd->config->runtime_flags) &&
1634 disk_openers(disk) == 0)
1635 nbd_disconnect_and_put(nbd);
1636
1637 nbd_config_put(nbd);
1638 nbd_put(nbd);
1639}
1640
1641static void nbd_free_disk(struct gendisk *disk)
1642{
1643 struct nbd_device *nbd = disk->private_data;
1644
1645 kfree(nbd);
1646}
1647
1648static const struct block_device_operations nbd_fops =
1649{
1650 .owner = THIS_MODULE,
1651 .open = nbd_open,
1652 .release = nbd_release,
1653 .ioctl = nbd_ioctl,
1654 .compat_ioctl = nbd_ioctl,
1655 .free_disk = nbd_free_disk,
1656};
1657
1658#if IS_ENABLED(CONFIG_DEBUG_FS)
1659
1660static int nbd_dbg_tasks_show(struct seq_file *s, void *unused)
1661{
1662 struct nbd_device *nbd = s->private;
1663
1664 if (nbd->pid)
1665 seq_printf(s, "recv: %d\n", nbd->pid);
1666
1667 return 0;
1668}
1669
1670DEFINE_SHOW_ATTRIBUTE(nbd_dbg_tasks);
1671
1672static int nbd_dbg_flags_show(struct seq_file *s, void *unused)
1673{
1674 struct nbd_device *nbd = s->private;
1675 u32 flags = nbd->config->flags;
1676
1677 seq_printf(s, "Hex: 0x%08x\n\n", flags);
1678
1679 seq_puts(s, "Known flags:\n");
1680
1681 if (flags & NBD_FLAG_HAS_FLAGS)
1682 seq_puts(s, "NBD_FLAG_HAS_FLAGS\n");
1683 if (flags & NBD_FLAG_READ_ONLY)
1684 seq_puts(s, "NBD_FLAG_READ_ONLY\n");
1685 if (flags & NBD_FLAG_SEND_FLUSH)
1686 seq_puts(s, "NBD_FLAG_SEND_FLUSH\n");
1687 if (flags & NBD_FLAG_SEND_FUA)
1688 seq_puts(s, "NBD_FLAG_SEND_FUA\n");
1689 if (flags & NBD_FLAG_SEND_TRIM)
1690 seq_puts(s, "NBD_FLAG_SEND_TRIM\n");
1691
1692 return 0;
1693}
1694
1695DEFINE_SHOW_ATTRIBUTE(nbd_dbg_flags);
1696
1697static int nbd_dev_dbg_init(struct nbd_device *nbd)
1698{
1699 struct dentry *dir;
1700 struct nbd_config *config = nbd->config;
1701
1702 if (!nbd_dbg_dir)
1703 return -EIO;
1704
1705 dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir);
1706 if (IS_ERR(dir)) {
1707 dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s'\n",
1708 nbd_name(nbd));
1709 return -EIO;
1710 }
1711 config->dbg_dir = dir;
1712
1713 debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_fops);
1714 debugfs_create_u64("size_bytes", 0444, dir, &config->bytesize);
1715 debugfs_create_u32("timeout", 0444, dir, &nbd->tag_set.timeout);
1716 debugfs_create_u32("blocksize_bits", 0444, dir, &config->blksize_bits);
1717 debugfs_create_file("flags", 0444, dir, nbd, &nbd_dbg_flags_fops);
1718
1719 return 0;
1720}
1721
1722static void nbd_dev_dbg_close(struct nbd_device *nbd)
1723{
1724 debugfs_remove_recursive(nbd->config->dbg_dir);
1725}
1726
1727static int nbd_dbg_init(void)
1728{
1729 struct dentry *dbg_dir;
1730
1731 dbg_dir = debugfs_create_dir("nbd", NULL);
1732 if (IS_ERR(dbg_dir))
1733 return -EIO;
1734
1735 nbd_dbg_dir = dbg_dir;
1736
1737 return 0;
1738}
1739
1740static void nbd_dbg_close(void)
1741{
1742 debugfs_remove_recursive(nbd_dbg_dir);
1743}
1744
1745#else /* IS_ENABLED(CONFIG_DEBUG_FS) */
1746
1747static int nbd_dev_dbg_init(struct nbd_device *nbd)
1748{
1749 return 0;
1750}
1751
1752static void nbd_dev_dbg_close(struct nbd_device *nbd)
1753{
1754}
1755
1756static int nbd_dbg_init(void)
1757{
1758 return 0;
1759}
1760
1761static void nbd_dbg_close(void)
1762{
1763}
1764
1765#endif
1766
1767static int nbd_init_request(struct blk_mq_tag_set *set, struct request *rq,
1768 unsigned int hctx_idx, unsigned int numa_node)
1769{
1770 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq);
1771 cmd->nbd = set->driver_data;
1772 cmd->flags = 0;
1773 mutex_init(&cmd->lock);
1774 return 0;
1775}
1776
1777static const struct blk_mq_ops nbd_mq_ops = {
1778 .queue_rq = nbd_queue_rq,
1779 .complete = nbd_complete_rq,
1780 .init_request = nbd_init_request,
1781 .timeout = nbd_xmit_timeout,
1782};
1783
1784static struct nbd_device *nbd_dev_add(int index, unsigned int refs)
1785{
1786 struct nbd_device *nbd;
1787 struct gendisk *disk;
1788 int err = -ENOMEM;
1789
1790 nbd = kzalloc(sizeof(struct nbd_device), GFP_KERNEL);
1791 if (!nbd)
1792 goto out;
1793
1794 nbd->tag_set.ops = &nbd_mq_ops;
1795 nbd->tag_set.nr_hw_queues = 1;
1796 nbd->tag_set.queue_depth = 128;
1797 nbd->tag_set.numa_node = NUMA_NO_NODE;
1798 nbd->tag_set.cmd_size = sizeof(struct nbd_cmd);
1799 nbd->tag_set.flags = BLK_MQ_F_SHOULD_MERGE |
1800 BLK_MQ_F_BLOCKING;
1801 nbd->tag_set.driver_data = nbd;
1802 INIT_WORK(&nbd->remove_work, nbd_dev_remove_work);
1803 nbd->backend = NULL;
1804
1805 err = blk_mq_alloc_tag_set(&nbd->tag_set);
1806 if (err)
1807 goto out_free_nbd;
1808
1809 mutex_lock(&nbd_index_mutex);
1810 if (index >= 0) {
1811 err = idr_alloc(&nbd_index_idr, nbd, index, index + 1,
1812 GFP_KERNEL);
1813 if (err == -ENOSPC)
1814 err = -EEXIST;
1815 } else {
1816 err = idr_alloc(&nbd_index_idr, nbd, 0,
1817 (MINORMASK >> part_shift) + 1, GFP_KERNEL);
1818 if (err >= 0)
1819 index = err;
1820 }
1821 nbd->index = index;
1822 mutex_unlock(&nbd_index_mutex);
1823 if (err < 0)
1824 goto out_free_tags;
1825
1826 disk = blk_mq_alloc_disk(&nbd->tag_set, NULL);
1827 if (IS_ERR(disk)) {
1828 err = PTR_ERR(disk);
1829 goto out_free_idr;
1830 }
1831 nbd->disk = disk;
1832
1833 nbd->recv_workq = alloc_workqueue("nbd%d-recv",
1834 WQ_MEM_RECLAIM | WQ_HIGHPRI |
1835 WQ_UNBOUND, 0, nbd->index);
1836 if (!nbd->recv_workq) {
1837 dev_err(disk_to_dev(nbd->disk), "Could not allocate knbd recv work queue.\n");
1838 err = -ENOMEM;
1839 goto out_err_disk;
1840 }
1841
1842 /*
1843 * Tell the block layer that we are not a rotational device
1844 */
1845 blk_queue_flag_set(QUEUE_FLAG_NONROT, disk->queue);
1846 blk_queue_max_discard_sectors(disk->queue, 0);
1847 blk_queue_max_segment_size(disk->queue, UINT_MAX);
1848 blk_queue_max_segments(disk->queue, USHRT_MAX);
1849 blk_queue_max_hw_sectors(disk->queue, 65536);
1850 disk->queue->limits.max_sectors = 256;
1851
1852 mutex_init(&nbd->config_lock);
1853 refcount_set(&nbd->config_refs, 0);
1854 /*
1855 * Start out with a zero references to keep other threads from using
1856 * this device until it is fully initialized.
1857 */
1858 refcount_set(&nbd->refs, 0);
1859 INIT_LIST_HEAD(&nbd->list);
1860 disk->major = NBD_MAJOR;
1861 disk->first_minor = index << part_shift;
1862 disk->minors = 1 << part_shift;
1863 disk->fops = &nbd_fops;
1864 disk->private_data = nbd;
1865 sprintf(disk->disk_name, "nbd%d", index);
1866 err = add_disk(disk);
1867 if (err)
1868 goto out_free_work;
1869
1870 /*
1871 * Now publish the device.
1872 */
1873 refcount_set(&nbd->refs, refs);
1874 nbd_total_devices++;
1875 return nbd;
1876
1877out_free_work:
1878 destroy_workqueue(nbd->recv_workq);
1879out_err_disk:
1880 put_disk(disk);
1881out_free_idr:
1882 mutex_lock(&nbd_index_mutex);
1883 idr_remove(&nbd_index_idr, index);
1884 mutex_unlock(&nbd_index_mutex);
1885out_free_tags:
1886 blk_mq_free_tag_set(&nbd->tag_set);
1887out_free_nbd:
1888 kfree(nbd);
1889out:
1890 return ERR_PTR(err);
1891}
1892
1893static struct nbd_device *nbd_find_get_unused(void)
1894{
1895 struct nbd_device *nbd;
1896 int id;
1897
1898 lockdep_assert_held(&nbd_index_mutex);
1899
1900 idr_for_each_entry(&nbd_index_idr, nbd, id) {
1901 if (refcount_read(&nbd->config_refs) ||
1902 test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags))
1903 continue;
1904 if (refcount_inc_not_zero(&nbd->refs))
1905 return nbd;
1906 }
1907
1908 return NULL;
1909}
1910
1911/* Netlink interface. */
1912static const struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = {
1913 [NBD_ATTR_INDEX] = { .type = NLA_U32 },
1914 [NBD_ATTR_SIZE_BYTES] = { .type = NLA_U64 },
1915 [NBD_ATTR_BLOCK_SIZE_BYTES] = { .type = NLA_U64 },
1916 [NBD_ATTR_TIMEOUT] = { .type = NLA_U64 },
1917 [NBD_ATTR_SERVER_FLAGS] = { .type = NLA_U64 },
1918 [NBD_ATTR_CLIENT_FLAGS] = { .type = NLA_U64 },
1919 [NBD_ATTR_SOCKETS] = { .type = NLA_NESTED},
1920 [NBD_ATTR_DEAD_CONN_TIMEOUT] = { .type = NLA_U64 },
1921 [NBD_ATTR_DEVICE_LIST] = { .type = NLA_NESTED},
1922 [NBD_ATTR_BACKEND_IDENTIFIER] = { .type = NLA_STRING},
1923};
1924
1925static const struct nla_policy nbd_sock_policy[NBD_SOCK_MAX + 1] = {
1926 [NBD_SOCK_FD] = { .type = NLA_U32 },
1927};
1928
1929/* We don't use this right now since we don't parse the incoming list, but we
1930 * still want it here so userspace knows what to expect.
1931 */
1932static const struct nla_policy __attribute__((unused))
1933nbd_device_policy[NBD_DEVICE_ATTR_MAX + 1] = {
1934 [NBD_DEVICE_INDEX] = { .type = NLA_U32 },
1935 [NBD_DEVICE_CONNECTED] = { .type = NLA_U8 },
1936};
1937
1938static int nbd_genl_size_set(struct genl_info *info, struct nbd_device *nbd)
1939{
1940 struct nbd_config *config = nbd->config;
1941 u64 bsize = nbd_blksize(config);
1942 u64 bytes = config->bytesize;
1943
1944 if (info->attrs[NBD_ATTR_SIZE_BYTES])
1945 bytes = nla_get_u64(info->attrs[NBD_ATTR_SIZE_BYTES]);
1946
1947 if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES])
1948 bsize = nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]);
1949
1950 if (bytes != config->bytesize || bsize != nbd_blksize(config))
1951 return nbd_set_size(nbd, bytes, bsize);
1952 return 0;
1953}
1954
1955static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
1956{
1957 struct nbd_device *nbd;
1958 struct nbd_config *config;
1959 int index = -1;
1960 int ret;
1961 bool put_dev = false;
1962
1963 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1964 return -EPERM;
1965
1966 if (info->attrs[NBD_ATTR_INDEX]) {
1967 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1968
1969 /*
1970 * Too big first_minor can cause duplicate creation of
1971 * sysfs files/links, since index << part_shift might overflow, or
1972 * MKDEV() expect that the max bits of first_minor is 20.
1973 */
1974 if (index < 0 || index > MINORMASK >> part_shift) {
1975 pr_err("illegal input index %d\n", index);
1976 return -EINVAL;
1977 }
1978 }
1979 if (GENL_REQ_ATTR_CHECK(info, NBD_ATTR_SOCKETS)) {
1980 pr_err("must specify at least one socket\n");
1981 return -EINVAL;
1982 }
1983 if (GENL_REQ_ATTR_CHECK(info, NBD_ATTR_SIZE_BYTES)) {
1984 pr_err("must specify a size in bytes for the device\n");
1985 return -EINVAL;
1986 }
1987again:
1988 mutex_lock(&nbd_index_mutex);
1989 if (index == -1) {
1990 nbd = nbd_find_get_unused();
1991 } else {
1992 nbd = idr_find(&nbd_index_idr, index);
1993 if (nbd) {
1994 if ((test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags) &&
1995 test_bit(NBD_DISCONNECT_REQUESTED, &nbd->flags)) ||
1996 !refcount_inc_not_zero(&nbd->refs)) {
1997 mutex_unlock(&nbd_index_mutex);
1998 pr_err("device at index %d is going down\n",
1999 index);
2000 return -EINVAL;
2001 }
2002 }
2003 }
2004 mutex_unlock(&nbd_index_mutex);
2005
2006 if (!nbd) {
2007 nbd = nbd_dev_add(index, 2);
2008 if (IS_ERR(nbd)) {
2009 pr_err("failed to add new device\n");
2010 return PTR_ERR(nbd);
2011 }
2012 }
2013
2014 mutex_lock(&nbd->config_lock);
2015 if (refcount_read(&nbd->config_refs)) {
2016 mutex_unlock(&nbd->config_lock);
2017 nbd_put(nbd);
2018 if (index == -1)
2019 goto again;
2020 pr_err("nbd%d already in use\n", index);
2021 return -EBUSY;
2022 }
2023
2024 ret = nbd_alloc_and_init_config(nbd);
2025 if (ret) {
2026 mutex_unlock(&nbd->config_lock);
2027 nbd_put(nbd);
2028 pr_err("couldn't allocate config\n");
2029 return ret;
2030 }
2031
2032 config = nbd->config;
2033 set_bit(NBD_RT_BOUND, &config->runtime_flags);
2034 ret = nbd_genl_size_set(info, nbd);
2035 if (ret)
2036 goto out;
2037
2038 if (info->attrs[NBD_ATTR_TIMEOUT])
2039 nbd_set_cmd_timeout(nbd,
2040 nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]));
2041 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
2042 config->dead_conn_timeout =
2043 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
2044 config->dead_conn_timeout *= HZ;
2045 }
2046 if (info->attrs[NBD_ATTR_SERVER_FLAGS])
2047 config->flags =
2048 nla_get_u64(info->attrs[NBD_ATTR_SERVER_FLAGS]);
2049 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
2050 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
2051 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
2052 /*
2053 * We have 1 ref to keep the device around, and then 1
2054 * ref for our current operation here, which will be
2055 * inherited by the config. If we already have
2056 * DESTROY_ON_DISCONNECT set then we know we don't have
2057 * that extra ref already held so we don't need the
2058 * put_dev.
2059 */
2060 if (!test_and_set_bit(NBD_DESTROY_ON_DISCONNECT,
2061 &nbd->flags))
2062 put_dev = true;
2063 } else {
2064 if (test_and_clear_bit(NBD_DESTROY_ON_DISCONNECT,
2065 &nbd->flags))
2066 refcount_inc(&nbd->refs);
2067 }
2068 if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {
2069 set_bit(NBD_RT_DISCONNECT_ON_CLOSE,
2070 &config->runtime_flags);
2071 }
2072 }
2073
2074 if (info->attrs[NBD_ATTR_SOCKETS]) {
2075 struct nlattr *attr;
2076 int rem, fd;
2077
2078 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
2079 rem) {
2080 struct nlattr *socks[NBD_SOCK_MAX+1];
2081
2082 if (nla_type(attr) != NBD_SOCK_ITEM) {
2083 pr_err("socks must be embedded in a SOCK_ITEM attr\n");
2084 ret = -EINVAL;
2085 goto out;
2086 }
2087 ret = nla_parse_nested_deprecated(socks, NBD_SOCK_MAX,
2088 attr,
2089 nbd_sock_policy,
2090 info->extack);
2091 if (ret != 0) {
2092 pr_err("error processing sock list\n");
2093 ret = -EINVAL;
2094 goto out;
2095 }
2096 if (!socks[NBD_SOCK_FD])
2097 continue;
2098 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
2099 ret = nbd_add_socket(nbd, fd, true);
2100 if (ret)
2101 goto out;
2102 }
2103 }
2104 ret = nbd_start_device(nbd);
2105 if (ret)
2106 goto out;
2107 if (info->attrs[NBD_ATTR_BACKEND_IDENTIFIER]) {
2108 nbd->backend = nla_strdup(info->attrs[NBD_ATTR_BACKEND_IDENTIFIER],
2109 GFP_KERNEL);
2110 if (!nbd->backend) {
2111 ret = -ENOMEM;
2112 goto out;
2113 }
2114 }
2115 ret = device_create_file(disk_to_dev(nbd->disk), &backend_attr);
2116 if (ret) {
2117 dev_err(disk_to_dev(nbd->disk),
2118 "device_create_file failed for backend!\n");
2119 goto out;
2120 }
2121 set_bit(NBD_RT_HAS_BACKEND_FILE, &config->runtime_flags);
2122out:
2123 mutex_unlock(&nbd->config_lock);
2124 if (!ret) {
2125 set_bit(NBD_RT_HAS_CONFIG_REF, &config->runtime_flags);
2126 refcount_inc(&nbd->config_refs);
2127 nbd_connect_reply(info, nbd->index);
2128 }
2129 nbd_config_put(nbd);
2130 if (put_dev)
2131 nbd_put(nbd);
2132 return ret;
2133}
2134
2135static void nbd_disconnect_and_put(struct nbd_device *nbd)
2136{
2137 mutex_lock(&nbd->config_lock);
2138 nbd_disconnect(nbd);
2139 sock_shutdown(nbd);
2140 wake_up(&nbd->config->conn_wait);
2141 /*
2142 * Make sure recv thread has finished, we can safely call nbd_clear_que()
2143 * to cancel the inflight I/Os.
2144 */
2145 flush_workqueue(nbd->recv_workq);
2146 nbd_clear_que(nbd);
2147 nbd->task_setup = NULL;
2148 mutex_unlock(&nbd->config_lock);
2149
2150 if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF,
2151 &nbd->config->runtime_flags))
2152 nbd_config_put(nbd);
2153}
2154
2155static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info)
2156{
2157 struct nbd_device *nbd;
2158 int index;
2159
2160 if (!netlink_capable(skb, CAP_SYS_ADMIN))
2161 return -EPERM;
2162
2163 if (GENL_REQ_ATTR_CHECK(info, NBD_ATTR_INDEX)) {
2164 pr_err("must specify an index to disconnect\n");
2165 return -EINVAL;
2166 }
2167 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2168 mutex_lock(&nbd_index_mutex);
2169 nbd = idr_find(&nbd_index_idr, index);
2170 if (!nbd) {
2171 mutex_unlock(&nbd_index_mutex);
2172 pr_err("couldn't find device at index %d\n", index);
2173 return -EINVAL;
2174 }
2175 if (!refcount_inc_not_zero(&nbd->refs)) {
2176 mutex_unlock(&nbd_index_mutex);
2177 pr_err("device at index %d is going down\n", index);
2178 return -EINVAL;
2179 }
2180 mutex_unlock(&nbd_index_mutex);
2181 if (!refcount_inc_not_zero(&nbd->config_refs))
2182 goto put_nbd;
2183 nbd_disconnect_and_put(nbd);
2184 nbd_config_put(nbd);
2185put_nbd:
2186 nbd_put(nbd);
2187 return 0;
2188}
2189
2190static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info)
2191{
2192 struct nbd_device *nbd = NULL;
2193 struct nbd_config *config;
2194 int index;
2195 int ret = 0;
2196 bool put_dev = false;
2197
2198 if (!netlink_capable(skb, CAP_SYS_ADMIN))
2199 return -EPERM;
2200
2201 if (GENL_REQ_ATTR_CHECK(info, NBD_ATTR_INDEX)) {
2202 pr_err("must specify a device to reconfigure\n");
2203 return -EINVAL;
2204 }
2205 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2206 mutex_lock(&nbd_index_mutex);
2207 nbd = idr_find(&nbd_index_idr, index);
2208 if (!nbd) {
2209 mutex_unlock(&nbd_index_mutex);
2210 pr_err("couldn't find a device at index %d\n", index);
2211 return -EINVAL;
2212 }
2213 if (nbd->backend) {
2214 if (info->attrs[NBD_ATTR_BACKEND_IDENTIFIER]) {
2215 if (nla_strcmp(info->attrs[NBD_ATTR_BACKEND_IDENTIFIER],
2216 nbd->backend)) {
2217 mutex_unlock(&nbd_index_mutex);
2218 dev_err(nbd_to_dev(nbd),
2219 "backend image doesn't match with %s\n",
2220 nbd->backend);
2221 return -EINVAL;
2222 }
2223 } else {
2224 mutex_unlock(&nbd_index_mutex);
2225 dev_err(nbd_to_dev(nbd), "must specify backend\n");
2226 return -EINVAL;
2227 }
2228 }
2229 if (!refcount_inc_not_zero(&nbd->refs)) {
2230 mutex_unlock(&nbd_index_mutex);
2231 pr_err("device at index %d is going down\n", index);
2232 return -EINVAL;
2233 }
2234 mutex_unlock(&nbd_index_mutex);
2235
2236 config = nbd_get_config_unlocked(nbd);
2237 if (!config) {
2238 dev_err(nbd_to_dev(nbd),
2239 "not configured, cannot reconfigure\n");
2240 nbd_put(nbd);
2241 return -EINVAL;
2242 }
2243
2244 mutex_lock(&nbd->config_lock);
2245 if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) ||
2246 !nbd->pid) {
2247 dev_err(nbd_to_dev(nbd),
2248 "not configured, cannot reconfigure\n");
2249 ret = -EINVAL;
2250 goto out;
2251 }
2252
2253 ret = nbd_genl_size_set(info, nbd);
2254 if (ret)
2255 goto out;
2256
2257 if (info->attrs[NBD_ATTR_TIMEOUT])
2258 nbd_set_cmd_timeout(nbd,
2259 nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]));
2260 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
2261 config->dead_conn_timeout =
2262 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
2263 config->dead_conn_timeout *= HZ;
2264 }
2265 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
2266 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
2267 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
2268 if (!test_and_set_bit(NBD_DESTROY_ON_DISCONNECT,
2269 &nbd->flags))
2270 put_dev = true;
2271 } else {
2272 if (test_and_clear_bit(NBD_DESTROY_ON_DISCONNECT,
2273 &nbd->flags))
2274 refcount_inc(&nbd->refs);
2275 }
2276
2277 if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {
2278 set_bit(NBD_RT_DISCONNECT_ON_CLOSE,
2279 &config->runtime_flags);
2280 } else {
2281 clear_bit(NBD_RT_DISCONNECT_ON_CLOSE,
2282 &config->runtime_flags);
2283 }
2284 }
2285
2286 if (info->attrs[NBD_ATTR_SOCKETS]) {
2287 struct nlattr *attr;
2288 int rem, fd;
2289
2290 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
2291 rem) {
2292 struct nlattr *socks[NBD_SOCK_MAX+1];
2293
2294 if (nla_type(attr) != NBD_SOCK_ITEM) {
2295 pr_err("socks must be embedded in a SOCK_ITEM attr\n");
2296 ret = -EINVAL;
2297 goto out;
2298 }
2299 ret = nla_parse_nested_deprecated(socks, NBD_SOCK_MAX,
2300 attr,
2301 nbd_sock_policy,
2302 info->extack);
2303 if (ret != 0) {
2304 pr_err("error processing sock list\n");
2305 ret = -EINVAL;
2306 goto out;
2307 }
2308 if (!socks[NBD_SOCK_FD])
2309 continue;
2310 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
2311 ret = nbd_reconnect_socket(nbd, fd);
2312 if (ret) {
2313 if (ret == -ENOSPC)
2314 ret = 0;
2315 goto out;
2316 }
2317 dev_info(nbd_to_dev(nbd), "reconnected socket\n");
2318 }
2319 }
2320out:
2321 mutex_unlock(&nbd->config_lock);
2322 nbd_config_put(nbd);
2323 nbd_put(nbd);
2324 if (put_dev)
2325 nbd_put(nbd);
2326 return ret;
2327}
2328
2329static const struct genl_small_ops nbd_connect_genl_ops[] = {
2330 {
2331 .cmd = NBD_CMD_CONNECT,
2332 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2333 .doit = nbd_genl_connect,
2334 },
2335 {
2336 .cmd = NBD_CMD_DISCONNECT,
2337 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2338 .doit = nbd_genl_disconnect,
2339 },
2340 {
2341 .cmd = NBD_CMD_RECONFIGURE,
2342 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2343 .doit = nbd_genl_reconfigure,
2344 },
2345 {
2346 .cmd = NBD_CMD_STATUS,
2347 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2348 .doit = nbd_genl_status,
2349 },
2350};
2351
2352static const struct genl_multicast_group nbd_mcast_grps[] = {
2353 { .name = NBD_GENL_MCAST_GROUP_NAME, },
2354};
2355
2356static struct genl_family nbd_genl_family __ro_after_init = {
2357 .hdrsize = 0,
2358 .name = NBD_GENL_FAMILY_NAME,
2359 .version = NBD_GENL_VERSION,
2360 .module = THIS_MODULE,
2361 .small_ops = nbd_connect_genl_ops,
2362 .n_small_ops = ARRAY_SIZE(nbd_connect_genl_ops),
2363 .resv_start_op = NBD_CMD_STATUS + 1,
2364 .maxattr = NBD_ATTR_MAX,
2365 .netnsok = 1,
2366 .policy = nbd_attr_policy,
2367 .mcgrps = nbd_mcast_grps,
2368 .n_mcgrps = ARRAY_SIZE(nbd_mcast_grps),
2369};
2370MODULE_ALIAS_GENL_FAMILY(NBD_GENL_FAMILY_NAME);
2371
2372static int populate_nbd_status(struct nbd_device *nbd, struct sk_buff *reply)
2373{
2374 struct nlattr *dev_opt;
2375 u8 connected = 0;
2376 int ret;
2377
2378 /* This is a little racey, but for status it's ok. The
2379 * reason we don't take a ref here is because we can't
2380 * take a ref in the index == -1 case as we would need
2381 * to put under the nbd_index_mutex, which could
2382 * deadlock if we are configured to remove ourselves
2383 * once we're disconnected.
2384 */
2385 if (refcount_read(&nbd->config_refs))
2386 connected = 1;
2387 dev_opt = nla_nest_start_noflag(reply, NBD_DEVICE_ITEM);
2388 if (!dev_opt)
2389 return -EMSGSIZE;
2390 ret = nla_put_u32(reply, NBD_DEVICE_INDEX, nbd->index);
2391 if (ret)
2392 return -EMSGSIZE;
2393 ret = nla_put_u8(reply, NBD_DEVICE_CONNECTED,
2394 connected);
2395 if (ret)
2396 return -EMSGSIZE;
2397 nla_nest_end(reply, dev_opt);
2398 return 0;
2399}
2400
2401static int status_cb(int id, void *ptr, void *data)
2402{
2403 struct nbd_device *nbd = ptr;
2404 return populate_nbd_status(nbd, (struct sk_buff *)data);
2405}
2406
2407static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info)
2408{
2409 struct nlattr *dev_list;
2410 struct sk_buff *reply;
2411 void *reply_head;
2412 size_t msg_size;
2413 int index = -1;
2414 int ret = -ENOMEM;
2415
2416 if (info->attrs[NBD_ATTR_INDEX])
2417 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2418
2419 mutex_lock(&nbd_index_mutex);
2420
2421 msg_size = nla_total_size(nla_attr_size(sizeof(u32)) +
2422 nla_attr_size(sizeof(u8)));
2423 msg_size *= (index == -1) ? nbd_total_devices : 1;
2424
2425 reply = genlmsg_new(msg_size, GFP_KERNEL);
2426 if (!reply)
2427 goto out;
2428 reply_head = genlmsg_put_reply(reply, info, &nbd_genl_family, 0,
2429 NBD_CMD_STATUS);
2430 if (!reply_head) {
2431 nlmsg_free(reply);
2432 goto out;
2433 }
2434
2435 dev_list = nla_nest_start_noflag(reply, NBD_ATTR_DEVICE_LIST);
2436 if (index == -1) {
2437 ret = idr_for_each(&nbd_index_idr, &status_cb, reply);
2438 if (ret) {
2439 nlmsg_free(reply);
2440 goto out;
2441 }
2442 } else {
2443 struct nbd_device *nbd;
2444 nbd = idr_find(&nbd_index_idr, index);
2445 if (nbd) {
2446 ret = populate_nbd_status(nbd, reply);
2447 if (ret) {
2448 nlmsg_free(reply);
2449 goto out;
2450 }
2451 }
2452 }
2453 nla_nest_end(reply, dev_list);
2454 genlmsg_end(reply, reply_head);
2455 ret = genlmsg_reply(reply, info);
2456out:
2457 mutex_unlock(&nbd_index_mutex);
2458 return ret;
2459}
2460
2461static void nbd_connect_reply(struct genl_info *info, int index)
2462{
2463 struct sk_buff *skb;
2464 void *msg_head;
2465 int ret;
2466
2467 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2468 if (!skb)
2469 return;
2470 msg_head = genlmsg_put_reply(skb, info, &nbd_genl_family, 0,
2471 NBD_CMD_CONNECT);
2472 if (!msg_head) {
2473 nlmsg_free(skb);
2474 return;
2475 }
2476 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2477 if (ret) {
2478 nlmsg_free(skb);
2479 return;
2480 }
2481 genlmsg_end(skb, msg_head);
2482 genlmsg_reply(skb, info);
2483}
2484
2485static void nbd_mcast_index(int index)
2486{
2487 struct sk_buff *skb;
2488 void *msg_head;
2489 int ret;
2490
2491 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2492 if (!skb)
2493 return;
2494 msg_head = genlmsg_put(skb, 0, 0, &nbd_genl_family, 0,
2495 NBD_CMD_LINK_DEAD);
2496 if (!msg_head) {
2497 nlmsg_free(skb);
2498 return;
2499 }
2500 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2501 if (ret) {
2502 nlmsg_free(skb);
2503 return;
2504 }
2505 genlmsg_end(skb, msg_head);
2506 genlmsg_multicast(&nbd_genl_family, skb, 0, 0, GFP_KERNEL);
2507}
2508
2509static void nbd_dead_link_work(struct work_struct *work)
2510{
2511 struct link_dead_args *args = container_of(work, struct link_dead_args,
2512 work);
2513 nbd_mcast_index(args->index);
2514 kfree(args);
2515}
2516
2517static int __init nbd_init(void)
2518{
2519 int i;
2520
2521 BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
2522
2523 if (max_part < 0) {
2524 pr_err("max_part must be >= 0\n");
2525 return -EINVAL;
2526 }
2527
2528 part_shift = 0;
2529 if (max_part > 0) {
2530 part_shift = fls(max_part);
2531
2532 /*
2533 * Adjust max_part according to part_shift as it is exported
2534 * to user space so that user can know the max number of
2535 * partition kernel should be able to manage.
2536 *
2537 * Note that -1 is required because partition 0 is reserved
2538 * for the whole disk.
2539 */
2540 max_part = (1UL << part_shift) - 1;
2541 }
2542
2543 if ((1UL << part_shift) > DISK_MAX_PARTS)
2544 return -EINVAL;
2545
2546 if (nbds_max > 1UL << (MINORBITS - part_shift))
2547 return -EINVAL;
2548
2549 if (register_blkdev(NBD_MAJOR, "nbd"))
2550 return -EIO;
2551
2552 nbd_del_wq = alloc_workqueue("nbd-del", WQ_UNBOUND, 0);
2553 if (!nbd_del_wq) {
2554 unregister_blkdev(NBD_MAJOR, "nbd");
2555 return -ENOMEM;
2556 }
2557
2558 if (genl_register_family(&nbd_genl_family)) {
2559 destroy_workqueue(nbd_del_wq);
2560 unregister_blkdev(NBD_MAJOR, "nbd");
2561 return -EINVAL;
2562 }
2563 nbd_dbg_init();
2564
2565 for (i = 0; i < nbds_max; i++)
2566 nbd_dev_add(i, 1);
2567 return 0;
2568}
2569
2570static int nbd_exit_cb(int id, void *ptr, void *data)
2571{
2572 struct list_head *list = (struct list_head *)data;
2573 struct nbd_device *nbd = ptr;
2574
2575 /* Skip nbd that is being removed asynchronously */
2576 if (refcount_read(&nbd->refs))
2577 list_add_tail(&nbd->list, list);
2578
2579 return 0;
2580}
2581
2582static void __exit nbd_cleanup(void)
2583{
2584 struct nbd_device *nbd;
2585 LIST_HEAD(del_list);
2586
2587 /*
2588 * Unregister netlink interface prior to waiting
2589 * for the completion of netlink commands.
2590 */
2591 genl_unregister_family(&nbd_genl_family);
2592
2593 nbd_dbg_close();
2594
2595 mutex_lock(&nbd_index_mutex);
2596 idr_for_each(&nbd_index_idr, &nbd_exit_cb, &del_list);
2597 mutex_unlock(&nbd_index_mutex);
2598
2599 while (!list_empty(&del_list)) {
2600 nbd = list_first_entry(&del_list, struct nbd_device, list);
2601 list_del_init(&nbd->list);
2602 if (refcount_read(&nbd->config_refs))
2603 pr_err("possibly leaking nbd_config (ref %d)\n",
2604 refcount_read(&nbd->config_refs));
2605 if (refcount_read(&nbd->refs) != 1)
2606 pr_err("possibly leaking a device\n");
2607 nbd_put(nbd);
2608 }
2609
2610 /* Also wait for nbd_dev_remove_work() completes */
2611 destroy_workqueue(nbd_del_wq);
2612
2613 idr_destroy(&nbd_index_idr);
2614 unregister_blkdev(NBD_MAJOR, "nbd");
2615}
2616
2617module_init(nbd_init);
2618module_exit(nbd_cleanup);
2619
2620MODULE_DESCRIPTION("Network Block Device");
2621MODULE_LICENSE("GPL");
2622
2623module_param(nbds_max, int, 0444);
2624MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
2625module_param(max_part, int, 0444);
2626MODULE_PARM_DESC(max_part, "number of partitions per device (default: 16)");