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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/*
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/types.h>
38
39#include <linux/nbd.h>
40
41#define NBD_MAGIC 0x68797548
42
43#ifdef NDEBUG
44#define dprintk(flags, fmt...)
45#else /* NDEBUG */
46#define dprintk(flags, fmt...) do { \
47 if (debugflags & (flags)) printk(KERN_DEBUG fmt); \
48} while (0)
49#define DBG_IOCTL 0x0004
50#define DBG_INIT 0x0010
51#define DBG_EXIT 0x0020
52#define DBG_BLKDEV 0x0100
53#define DBG_RX 0x0200
54#define DBG_TX 0x0400
55static unsigned int debugflags;
56#endif /* NDEBUG */
57
58static unsigned int nbds_max = 16;
59static struct nbd_device *nbd_dev;
60static int max_part;
61
62/*
63 * Use just one lock (or at most 1 per NIC). Two arguments for this:
64 * 1. Each NIC is essentially a synchronization point for all servers
65 * accessed through that NIC so there's no need to have more locks
66 * than NICs anyway.
67 * 2. More locks lead to more "Dirty cache line bouncing" which will slow
68 * down each lock to the point where they're actually slower than just
69 * a single lock.
70 * Thanks go to Jens Axboe and Al Viro for their LKML emails explaining this!
71 */
72static DEFINE_SPINLOCK(nbd_lock);
73
74#ifndef NDEBUG
75static const char *ioctl_cmd_to_ascii(int cmd)
76{
77 switch (cmd) {
78 case NBD_SET_SOCK: return "set-sock";
79 case NBD_SET_BLKSIZE: return "set-blksize";
80 case NBD_SET_SIZE: return "set-size";
81 case NBD_DO_IT: return "do-it";
82 case NBD_CLEAR_SOCK: return "clear-sock";
83 case NBD_CLEAR_QUE: return "clear-que";
84 case NBD_PRINT_DEBUG: return "print-debug";
85 case NBD_SET_SIZE_BLOCKS: return "set-size-blocks";
86 case NBD_DISCONNECT: return "disconnect";
87 case BLKROSET: return "set-read-only";
88 case BLKFLSBUF: return "flush-buffer-cache";
89 }
90 return "unknown";
91}
92
93static const char *nbdcmd_to_ascii(int cmd)
94{
95 switch (cmd) {
96 case NBD_CMD_READ: return "read";
97 case NBD_CMD_WRITE: return "write";
98 case NBD_CMD_DISC: return "disconnect";
99 }
100 return "invalid";
101}
102#endif /* NDEBUG */
103
104static void nbd_end_request(struct request *req)
105{
106 int error = req->errors ? -EIO : 0;
107 struct request_queue *q = req->q;
108 unsigned long flags;
109
110 dprintk(DBG_BLKDEV, "%s: request %p: %s\n", req->rq_disk->disk_name,
111 req, error ? "failed" : "done");
112
113 spin_lock_irqsave(q->queue_lock, flags);
114 __blk_end_request_all(req, error);
115 spin_unlock_irqrestore(q->queue_lock, flags);
116}
117
118static void sock_shutdown(struct nbd_device *nbd, int lock)
119{
120 /* Forcibly shutdown the socket causing all listeners
121 * to error
122 *
123 * FIXME: This code is duplicated from sys_shutdown, but
124 * there should be a more generic interface rather than
125 * calling socket ops directly here */
126 if (lock)
127 mutex_lock(&nbd->tx_lock);
128 if (nbd->sock) {
129 dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
130 kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
131 nbd->sock = NULL;
132 }
133 if (lock)
134 mutex_unlock(&nbd->tx_lock);
135}
136
137static void nbd_xmit_timeout(unsigned long arg)
138{
139 struct task_struct *task = (struct task_struct *)arg;
140
141 printk(KERN_WARNING "nbd: killing hung xmit (%s, pid: %d)\n",
142 task->comm, task->pid);
143 force_sig(SIGKILL, task);
144}
145
146/*
147 * Send or receive packet.
148 */
149static int sock_xmit(struct nbd_device *nbd, int send, void *buf, int size,
150 int msg_flags)
151{
152 struct socket *sock = nbd->sock;
153 int result;
154 struct msghdr msg;
155 struct kvec iov;
156 sigset_t blocked, oldset;
157
158 if (unlikely(!sock)) {
159 dev_err(disk_to_dev(nbd->disk),
160 "Attempted %s on closed socket in sock_xmit\n",
161 (send ? "send" : "recv"));
162 return -EINVAL;
163 }
164
165 /* Allow interception of SIGKILL only
166 * Don't allow other signals to interrupt the transmission */
167 siginitsetinv(&blocked, sigmask(SIGKILL));
168 sigprocmask(SIG_SETMASK, &blocked, &oldset);
169
170 do {
171 sock->sk->sk_allocation = GFP_NOIO;
172 iov.iov_base = buf;
173 iov.iov_len = size;
174 msg.msg_name = NULL;
175 msg.msg_namelen = 0;
176 msg.msg_control = NULL;
177 msg.msg_controllen = 0;
178 msg.msg_flags = msg_flags | MSG_NOSIGNAL;
179
180 if (send) {
181 struct timer_list ti;
182
183 if (nbd->xmit_timeout) {
184 init_timer(&ti);
185 ti.function = nbd_xmit_timeout;
186 ti.data = (unsigned long)current;
187 ti.expires = jiffies + nbd->xmit_timeout;
188 add_timer(&ti);
189 }
190 result = kernel_sendmsg(sock, &msg, &iov, 1, size);
191 if (nbd->xmit_timeout)
192 del_timer_sync(&ti);
193 } else
194 result = kernel_recvmsg(sock, &msg, &iov, 1, size,
195 msg.msg_flags);
196
197 if (signal_pending(current)) {
198 siginfo_t info;
199 printk(KERN_WARNING "nbd (pid %d: %s) got signal %d\n",
200 task_pid_nr(current), current->comm,
201 dequeue_signal_lock(current, ¤t->blocked, &info));
202 result = -EINTR;
203 sock_shutdown(nbd, !send);
204 break;
205 }
206
207 if (result <= 0) {
208 if (result == 0)
209 result = -EPIPE; /* short read */
210 break;
211 }
212 size -= result;
213 buf += result;
214 } while (size > 0);
215
216 sigprocmask(SIG_SETMASK, &oldset, NULL);
217
218 return result;
219}
220
221static inline int sock_send_bvec(struct nbd_device *nbd, struct bio_vec *bvec,
222 int flags)
223{
224 int result;
225 void *kaddr = kmap(bvec->bv_page);
226 result = sock_xmit(nbd, 1, kaddr + bvec->bv_offset,
227 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 *nbd, 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 nbd->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(nbd, 1, &request, sizeof(request),
251 (nbd_cmd(req) == NBD_CMD_WRITE) ? MSG_MORE : 0);
252 if (result <= 0) {
253 dev_err(disk_to_dev(nbd->disk),
254 "Send control failed (result %d)\n", 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 nbd->disk->disk_name, req, bvec->bv_len);
271 result = sock_send_bvec(nbd, bvec, flags);
272 if (result <= 0) {
273 dev_err(disk_to_dev(nbd->disk),
274 "Send data failed (result %d)\n",
275 result);
276 goto error_out;
277 }
278 }
279 }
280 return 0;
281
282error_out:
283 return -EIO;
284}
285
286static struct request *nbd_find_request(struct nbd_device *nbd,
287 struct request *xreq)
288{
289 struct request *req, *tmp;
290 int err;
291
292 err = wait_event_interruptible(nbd->active_wq, nbd->active_req != xreq);
293 if (unlikely(err))
294 goto out;
295
296 spin_lock(&nbd->queue_lock);
297 list_for_each_entry_safe(req, tmp, &nbd->queue_head, queuelist) {
298 if (req != xreq)
299 continue;
300 list_del_init(&req->queuelist);
301 spin_unlock(&nbd->queue_lock);
302 return req;
303 }
304 spin_unlock(&nbd->queue_lock);
305
306 err = -ENOENT;
307
308out:
309 return ERR_PTR(err);
310}
311
312static inline int sock_recv_bvec(struct nbd_device *nbd, struct bio_vec *bvec)
313{
314 int result;
315 void *kaddr = kmap(bvec->bv_page);
316 result = sock_xmit(nbd, 0, kaddr + bvec->bv_offset, bvec->bv_len,
317 MSG_WAITALL);
318 kunmap(bvec->bv_page);
319 return result;
320}
321
322/* NULL returned = something went wrong, inform userspace */
323static struct request *nbd_read_stat(struct nbd_device *nbd)
324{
325 int result;
326 struct nbd_reply reply;
327 struct request *req;
328
329 reply.magic = 0;
330 result = sock_xmit(nbd, 0, &reply, sizeof(reply), MSG_WAITALL);
331 if (result <= 0) {
332 dev_err(disk_to_dev(nbd->disk),
333 "Receive control failed (result %d)\n", result);
334 goto harderror;
335 }
336
337 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) {
338 dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n",
339 (unsigned long)ntohl(reply.magic));
340 result = -EPROTO;
341 goto harderror;
342 }
343
344 req = nbd_find_request(nbd, *(struct request **)reply.handle);
345 if (IS_ERR(req)) {
346 result = PTR_ERR(req);
347 if (result != -ENOENT)
348 goto harderror;
349
350 dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%p)\n",
351 reply.handle);
352 result = -EBADR;
353 goto harderror;
354 }
355
356 if (ntohl(reply.error)) {
357 dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n",
358 ntohl(reply.error));
359 req->errors++;
360 return req;
361 }
362
363 dprintk(DBG_RX, "%s: request %p: got reply\n",
364 nbd->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(nbd, bvec);
371 if (result <= 0) {
372 dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
373 result);
374 req->errors++;
375 return req;
376 }
377 dprintk(DBG_RX, "%s: request %p: got %d bytes data\n",
378 nbd->disk->disk_name, req, bvec->bv_len);
379 }
380 }
381 return req;
382harderror:
383 nbd->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 *nbd)
402{
403 struct request *req;
404 int ret;
405
406 BUG_ON(nbd->magic != NBD_MAGIC);
407
408 nbd->pid = task_pid_nr(current);
409 ret = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
410 if (ret) {
411 dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n");
412 nbd->pid = 0;
413 return ret;
414 }
415
416 while ((req = nbd_read_stat(nbd)) != NULL)
417 nbd_end_request(req);
418
419 device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
420 nbd->pid = 0;
421 return 0;
422}
423
424static void nbd_clear_que(struct nbd_device *nbd)
425{
426 struct request *req;
427
428 BUG_ON(nbd->magic != NBD_MAGIC);
429
430 /*
431 * Because we have set nbd->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(nbd->sock);
439 BUG_ON(nbd->active_req);
440
441 while (!list_empty(&nbd->queue_head)) {
442 req = list_entry(nbd->queue_head.next, struct request,
443 queuelist);
444 list_del_init(&req->queuelist);
445 req->errors++;
446 nbd_end_request(req);
447 }
448
449 while (!list_empty(&nbd->waiting_queue)) {
450 req = list_entry(nbd->waiting_queue.next, struct request,
451 queuelist);
452 list_del_init(&req->queuelist);
453 req->errors++;
454 nbd_end_request(req);
455 }
456}
457
458
459static void nbd_handle_req(struct nbd_device *nbd, struct request *req)
460{
461 if (req->cmd_type != REQ_TYPE_FS)
462 goto error_out;
463
464 nbd_cmd(req) = NBD_CMD_READ;
465 if (rq_data_dir(req) == WRITE) {
466 nbd_cmd(req) = NBD_CMD_WRITE;
467 if (nbd->flags & NBD_READ_ONLY) {
468 dev_err(disk_to_dev(nbd->disk),
469 "Write on read-only\n");
470 goto error_out;
471 }
472 }
473
474 req->errors = 0;
475
476 mutex_lock(&nbd->tx_lock);
477 if (unlikely(!nbd->sock)) {
478 mutex_unlock(&nbd->tx_lock);
479 dev_err(disk_to_dev(nbd->disk),
480 "Attempted send on closed socket\n");
481 goto error_out;
482 }
483
484 nbd->active_req = req;
485
486 if (nbd_send_req(nbd, req) != 0) {
487 dev_err(disk_to_dev(nbd->disk), "Request send failed\n");
488 req->errors++;
489 nbd_end_request(req);
490 } else {
491 spin_lock(&nbd->queue_lock);
492 list_add(&req->queuelist, &nbd->queue_head);
493 spin_unlock(&nbd->queue_lock);
494 }
495
496 nbd->active_req = NULL;
497 mutex_unlock(&nbd->tx_lock);
498 wake_up_all(&nbd->active_wq);
499
500 return;
501
502error_out:
503 req->errors++;
504 nbd_end_request(req);
505}
506
507static int nbd_thread(void *data)
508{
509 struct nbd_device *nbd = data;
510 struct request *req;
511
512 set_user_nice(current, -20);
513 while (!kthread_should_stop() || !list_empty(&nbd->waiting_queue)) {
514 /* wait for something to do */
515 wait_event_interruptible(nbd->waiting_wq,
516 kthread_should_stop() ||
517 !list_empty(&nbd->waiting_queue));
518
519 /* extract request */
520 if (list_empty(&nbd->waiting_queue))
521 continue;
522
523 spin_lock_irq(&nbd->queue_lock);
524 req = list_entry(nbd->waiting_queue.next, struct request,
525 queuelist);
526 list_del_init(&req->queuelist);
527 spin_unlock_irq(&nbd->queue_lock);
528
529 /* handle request */
530 nbd_handle_req(nbd, req);
531 }
532 return 0;
533}
534
535/*
536 * We always wait for result of write, for now. It would be nice to make it optional
537 * in future
538 * if ((rq_data_dir(req) == WRITE) && (nbd->flags & NBD_WRITE_NOCHK))
539 * { printk( "Warning: Ignoring result!\n"); nbd_end_request( req ); }
540 */
541
542static void do_nbd_request(struct request_queue *q)
543{
544 struct request *req;
545
546 while ((req = blk_fetch_request(q)) != NULL) {
547 struct nbd_device *nbd;
548
549 spin_unlock_irq(q->queue_lock);
550
551 dprintk(DBG_BLKDEV, "%s: request %p: dequeued (flags=%x)\n",
552 req->rq_disk->disk_name, req, req->cmd_type);
553
554 nbd = req->rq_disk->private_data;
555
556 BUG_ON(nbd->magic != NBD_MAGIC);
557
558 if (unlikely(!nbd->sock)) {
559 dev_err(disk_to_dev(nbd->disk),
560 "Attempted send on closed socket\n");
561 req->errors++;
562 nbd_end_request(req);
563 spin_lock_irq(q->queue_lock);
564 continue;
565 }
566
567 spin_lock_irq(&nbd->queue_lock);
568 list_add_tail(&req->queuelist, &nbd->waiting_queue);
569 spin_unlock_irq(&nbd->queue_lock);
570
571 wake_up(&nbd->waiting_wq);
572
573 spin_lock_irq(q->queue_lock);
574 }
575}
576
577/* Must be called with tx_lock held */
578
579static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
580 unsigned int cmd, unsigned long arg)
581{
582 switch (cmd) {
583 case NBD_DISCONNECT: {
584 struct request sreq;
585
586 dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
587
588 blk_rq_init(NULL, &sreq);
589 sreq.cmd_type = REQ_TYPE_SPECIAL;
590 nbd_cmd(&sreq) = NBD_CMD_DISC;
591 if (!nbd->sock)
592 return -EINVAL;
593 nbd_send_req(nbd, &sreq);
594 return 0;
595 }
596
597 case NBD_CLEAR_SOCK: {
598 struct file *file;
599
600 nbd->sock = NULL;
601 file = nbd->file;
602 nbd->file = NULL;
603 nbd_clear_que(nbd);
604 BUG_ON(!list_empty(&nbd->queue_head));
605 BUG_ON(!list_empty(&nbd->waiting_queue));
606 if (file)
607 fput(file);
608 return 0;
609 }
610
611 case NBD_SET_SOCK: {
612 struct file *file;
613 if (nbd->file)
614 return -EBUSY;
615 file = fget(arg);
616 if (file) {
617 struct inode *inode = file->f_path.dentry->d_inode;
618 if (S_ISSOCK(inode->i_mode)) {
619 nbd->file = file;
620 nbd->sock = SOCKET_I(inode);
621 if (max_part > 0)
622 bdev->bd_invalidated = 1;
623 return 0;
624 } else {
625 fput(file);
626 }
627 }
628 return -EINVAL;
629 }
630
631 case NBD_SET_BLKSIZE:
632 nbd->blksize = arg;
633 nbd->bytesize &= ~(nbd->blksize-1);
634 bdev->bd_inode->i_size = nbd->bytesize;
635 set_blocksize(bdev, nbd->blksize);
636 set_capacity(nbd->disk, nbd->bytesize >> 9);
637 return 0;
638
639 case NBD_SET_SIZE:
640 nbd->bytesize = arg & ~(nbd->blksize-1);
641 bdev->bd_inode->i_size = nbd->bytesize;
642 set_blocksize(bdev, nbd->blksize);
643 set_capacity(nbd->disk, nbd->bytesize >> 9);
644 return 0;
645
646 case NBD_SET_TIMEOUT:
647 nbd->xmit_timeout = arg * HZ;
648 return 0;
649
650 case NBD_SET_SIZE_BLOCKS:
651 nbd->bytesize = ((u64) arg) * nbd->blksize;
652 bdev->bd_inode->i_size = nbd->bytesize;
653 set_blocksize(bdev, nbd->blksize);
654 set_capacity(nbd->disk, nbd->bytesize >> 9);
655 return 0;
656
657 case NBD_DO_IT: {
658 struct task_struct *thread;
659 struct file *file;
660 int error;
661
662 if (nbd->pid)
663 return -EBUSY;
664 if (!nbd->file)
665 return -EINVAL;
666
667 mutex_unlock(&nbd->tx_lock);
668
669 thread = kthread_create(nbd_thread, nbd, nbd->disk->disk_name);
670 if (IS_ERR(thread)) {
671 mutex_lock(&nbd->tx_lock);
672 return PTR_ERR(thread);
673 }
674 wake_up_process(thread);
675 error = nbd_do_it(nbd);
676 kthread_stop(thread);
677
678 mutex_lock(&nbd->tx_lock);
679 if (error)
680 return error;
681 sock_shutdown(nbd, 0);
682 file = nbd->file;
683 nbd->file = NULL;
684 nbd_clear_que(nbd);
685 dev_warn(disk_to_dev(nbd->disk), "queue cleared\n");
686 if (file)
687 fput(file);
688 nbd->bytesize = 0;
689 bdev->bd_inode->i_size = 0;
690 set_capacity(nbd->disk, 0);
691 if (max_part > 0)
692 ioctl_by_bdev(bdev, BLKRRPART, 0);
693 return nbd->harderror;
694 }
695
696 case NBD_CLEAR_QUE:
697 /*
698 * This is for compatibility only. The queue is always cleared
699 * by NBD_DO_IT or NBD_CLEAR_SOCK.
700 */
701 BUG_ON(!nbd->sock && !list_empty(&nbd->queue_head));
702 return 0;
703
704 case NBD_PRINT_DEBUG:
705 dev_info(disk_to_dev(nbd->disk),
706 "next = %p, prev = %p, head = %p\n",
707 nbd->queue_head.next, nbd->queue_head.prev,
708 &nbd->queue_head);
709 return 0;
710 }
711 return -ENOTTY;
712}
713
714static int nbd_ioctl(struct block_device *bdev, fmode_t mode,
715 unsigned int cmd, unsigned long arg)
716{
717 struct nbd_device *nbd = bdev->bd_disk->private_data;
718 int error;
719
720 if (!capable(CAP_SYS_ADMIN))
721 return -EPERM;
722
723 BUG_ON(nbd->magic != NBD_MAGIC);
724
725 /* Anyone capable of this syscall can do *real bad* things */
726 dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n",
727 nbd->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg);
728
729 mutex_lock(&nbd->tx_lock);
730 error = __nbd_ioctl(bdev, nbd, cmd, arg);
731 mutex_unlock(&nbd->tx_lock);
732
733 return error;
734}
735
736static const struct block_device_operations nbd_fops =
737{
738 .owner = THIS_MODULE,
739 .ioctl = nbd_ioctl,
740};
741
742/*
743 * And here should be modules and kernel interface
744 * (Just smiley confuses emacs :-)
745 */
746
747static int __init nbd_init(void)
748{
749 int err = -ENOMEM;
750 int i;
751 int part_shift;
752
753 BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
754
755 if (max_part < 0) {
756 printk(KERN_ERR "nbd: max_part must be >= 0\n");
757 return -EINVAL;
758 }
759
760 nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL);
761 if (!nbd_dev)
762 return -ENOMEM;
763
764 part_shift = 0;
765 if (max_part > 0) {
766 part_shift = fls(max_part);
767
768 /*
769 * Adjust max_part according to part_shift as it is exported
770 * to user space so that user can know the max number of
771 * partition kernel should be able to manage.
772 *
773 * Note that -1 is required because partition 0 is reserved
774 * for the whole disk.
775 */
776 max_part = (1UL << part_shift) - 1;
777 }
778
779 if ((1UL << part_shift) > DISK_MAX_PARTS)
780 return -EINVAL;
781
782 if (nbds_max > 1UL << (MINORBITS - part_shift))
783 return -EINVAL;
784
785 for (i = 0; i < nbds_max; i++) {
786 struct gendisk *disk = alloc_disk(1 << part_shift);
787 if (!disk)
788 goto out;
789 nbd_dev[i].disk = disk;
790 /*
791 * The new linux 2.5 block layer implementation requires
792 * every gendisk to have its very own request_queue struct.
793 * These structs are big so we dynamically allocate them.
794 */
795 disk->queue = blk_init_queue(do_nbd_request, &nbd_lock);
796 if (!disk->queue) {
797 put_disk(disk);
798 goto out;
799 }
800 /*
801 * Tell the block layer that we are not a rotational device
802 */
803 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue);
804 }
805
806 if (register_blkdev(NBD_MAJOR, "nbd")) {
807 err = -EIO;
808 goto out;
809 }
810
811 printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR);
812 dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags);
813
814 for (i = 0; i < nbds_max; i++) {
815 struct gendisk *disk = nbd_dev[i].disk;
816 nbd_dev[i].file = NULL;
817 nbd_dev[i].magic = NBD_MAGIC;
818 nbd_dev[i].flags = 0;
819 INIT_LIST_HEAD(&nbd_dev[i].waiting_queue);
820 spin_lock_init(&nbd_dev[i].queue_lock);
821 INIT_LIST_HEAD(&nbd_dev[i].queue_head);
822 mutex_init(&nbd_dev[i].tx_lock);
823 init_waitqueue_head(&nbd_dev[i].active_wq);
824 init_waitqueue_head(&nbd_dev[i].waiting_wq);
825 nbd_dev[i].blksize = 1024;
826 nbd_dev[i].bytesize = 0;
827 disk->major = NBD_MAJOR;
828 disk->first_minor = i << part_shift;
829 disk->fops = &nbd_fops;
830 disk->private_data = &nbd_dev[i];
831 sprintf(disk->disk_name, "nbd%d", i);
832 set_capacity(disk, 0);
833 add_disk(disk);
834 }
835
836 return 0;
837out:
838 while (i--) {
839 blk_cleanup_queue(nbd_dev[i].disk->queue);
840 put_disk(nbd_dev[i].disk);
841 }
842 kfree(nbd_dev);
843 return err;
844}
845
846static void __exit nbd_cleanup(void)
847{
848 int i;
849 for (i = 0; i < nbds_max; i++) {
850 struct gendisk *disk = nbd_dev[i].disk;
851 nbd_dev[i].magic = 0;
852 if (disk) {
853 del_gendisk(disk);
854 blk_cleanup_queue(disk->queue);
855 put_disk(disk);
856 }
857 }
858 unregister_blkdev(NBD_MAJOR, "nbd");
859 kfree(nbd_dev);
860 printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR);
861}
862
863module_init(nbd_init);
864module_exit(nbd_cleanup);
865
866MODULE_DESCRIPTION("Network Block Device");
867MODULE_LICENSE("GPL");
868
869module_param(nbds_max, int, 0444);
870MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
871module_param(max_part, int, 0444);
872MODULE_PARM_DESC(max_part, "number of partitions per device (default: 0)");
873#ifndef NDEBUG
874module_param(debugflags, int, 0644);
875MODULE_PARM_DESC(debugflags, "flags for controlling debug output");
876#endif