blob: 6997d8e6bfb5d70e9dfcc25d391be36ae2799a87 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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 Pavel Machek <pavel@ucw.cz>
8 * Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com>
9 *
10 * (part of code stolen from loop.c)
11 *
12 * 97-3-25 compiled 0-th version, not yet tested it
13 * (it did not work, BTW) (later that day) HEY! it works!
14 * (bit later) hmm, not that much... 2:00am next day:
15 * yes, it works, but it gives something like 50kB/sec
16 * 97-4-01 complete rewrite to make it possible for many requests at
17 * once to be processed
18 * 97-4-11 Making protocol independent of endianity etc.
19 * 97-9-13 Cosmetic changes
20 * 98-5-13 Attempt to make 64-bit-clean on 64-bit machines
21 * 99-1-11 Attempt to make 64-bit-clean on 32-bit machines <ankry@mif.pg.gda.pl>
22 * 01-2-27 Fix to store proper blockcount for kernel (calculated using
23 * BLOCK_SIZE_BITS, not device blocksize) <aga@permonline.ru>
24 * 01-3-11 Make nbd work with new Linux block layer code. It now supports
25 * plugging like all the other block devices. Also added in MSG_MORE to
26 * reduce number of partial TCP segments sent. <steve@chygwyn.com>
27 * 01-12-6 Fix deadlock condition by making queue locks independent of
28 * the transmit lock. <steve@chygwyn.com>
29 * 02-10-11 Allow hung xmit to be aborted via SIGKILL & various fixes.
30 * <Paul.Clements@SteelEye.com> <James.Bottomley@SteelEye.com>
31 * 03-06-22 Make nbd work with new linux 2.5 block layer design. This fixes
32 * memory corruption from module removal and possible memory corruption
33 * from sending/receiving disk data. <ldl@aros.net>
34 * 03-06-23 Cosmetic changes. <ldl@aros.net>
35 * 03-06-23 Enhance diagnostics support. <ldl@aros.net>
36 * 03-06-24 Remove unneeded blksize_bits field from nbd_device struct.
37 * <ldl@aros.net>
38 * 03-06-24 Cleanup PARANOIA usage & code. <ldl@aros.net>
39 * 04-02-19 Remove PARANOIA, plus various cleanups (Paul Clements)
40 * possible FIXME: make set_sock / set_blksize / set_size / do_it one syscall
41 * why not: would need access_ok and friends, would share yet another
42 * structure with userland
43 */
44
45#include <linux/major.h>
46
47#include <linux/blkdev.h>
48#include <linux/module.h>
49#include <linux/init.h>
50#include <linux/sched.h>
51#include <linux/fs.h>
52#include <linux/bio.h>
53#include <linux/stat.h>
54#include <linux/errno.h>
55#include <linux/file.h>
56#include <linux/ioctl.h>
Herbert Xu4b2f0262006-01-06 00:09:47 -080057#include <linux/compiler.h>
58#include <linux/err.h>
59#include <linux/kernel.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070060#include <net/sock.h>
61
62#include <linux/devfs_fs_kernel.h>
63
64#include <asm/uaccess.h>
Herbert Xu4b2f0262006-01-06 00:09:47 -080065#include <asm/system.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070066#include <asm/types.h>
67
68#include <linux/nbd.h>
69
70#define LO_MAGIC 0x68797548
71
72#ifdef NDEBUG
73#define dprintk(flags, fmt...)
74#else /* NDEBUG */
75#define dprintk(flags, fmt...) do { \
76 if (debugflags & (flags)) printk(KERN_DEBUG fmt); \
77} while (0)
78#define DBG_IOCTL 0x0004
79#define DBG_INIT 0x0010
80#define DBG_EXIT 0x0020
81#define DBG_BLKDEV 0x0100
82#define DBG_RX 0x0200
83#define DBG_TX 0x0400
84static unsigned int debugflags;
Lars Marowsky-Bree40be0c22005-05-01 08:59:07 -070085static unsigned int nbds_max = 16;
Linus Torvalds1da177e2005-04-16 15:20:36 -070086#endif /* NDEBUG */
87
88static struct nbd_device nbd_dev[MAX_NBD];
89
90/*
91 * Use just one lock (or at most 1 per NIC). Two arguments for this:
92 * 1. Each NIC is essentially a synchronization point for all servers
93 * accessed through that NIC so there's no need to have more locks
94 * than NICs anyway.
95 * 2. More locks lead to more "Dirty cache line bouncing" which will slow
96 * down each lock to the point where they're actually slower than just
97 * a single lock.
98 * Thanks go to Jens Axboe and Al Viro for their LKML emails explaining this!
99 */
100static DEFINE_SPINLOCK(nbd_lock);
101
102#ifndef NDEBUG
103static const char *ioctl_cmd_to_ascii(int cmd)
104{
105 switch (cmd) {
106 case NBD_SET_SOCK: return "set-sock";
107 case NBD_SET_BLKSIZE: return "set-blksize";
108 case NBD_SET_SIZE: return "set-size";
109 case NBD_DO_IT: return "do-it";
110 case NBD_CLEAR_SOCK: return "clear-sock";
111 case NBD_CLEAR_QUE: return "clear-que";
112 case NBD_PRINT_DEBUG: return "print-debug";
113 case NBD_SET_SIZE_BLOCKS: return "set-size-blocks";
114 case NBD_DISCONNECT: return "disconnect";
115 case BLKROSET: return "set-read-only";
116 case BLKFLSBUF: return "flush-buffer-cache";
117 }
118 return "unknown";
119}
120
121static const char *nbdcmd_to_ascii(int cmd)
122{
123 switch (cmd) {
124 case NBD_CMD_READ: return "read";
125 case NBD_CMD_WRITE: return "write";
126 case NBD_CMD_DISC: return "disconnect";
127 }
128 return "invalid";
129}
130#endif /* NDEBUG */
131
132static void nbd_end_request(struct request *req)
133{
134 int uptodate = (req->errors == 0) ? 1 : 0;
135 request_queue_t *q = req->q;
136 unsigned long flags;
137
138 dprintk(DBG_BLKDEV, "%s: request %p: %s\n", req->rq_disk->disk_name,
139 req, uptodate? "done": "failed");
140
141 spin_lock_irqsave(q->queue_lock, flags);
142 if (!end_that_request_first(req, uptodate, req->nr_sectors)) {
Tejun Heo8ffdc652006-01-06 09:49:03 +0100143 end_that_request_last(req, uptodate);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 }
145 spin_unlock_irqrestore(q->queue_lock, flags);
146}
147
148/*
149 * Send or receive packet.
150 */
151static int sock_xmit(struct socket *sock, int send, void *buf, int size,
152 int msg_flags)
153{
154 int result;
155 struct msghdr msg;
156 struct kvec iov;
157 unsigned long flags;
158 sigset_t oldset;
159
160 /* Allow interception of SIGKILL only
161 * Don't allow other signals to interrupt the transmission */
162 spin_lock_irqsave(&current->sighand->siglock, flags);
163 oldset = current->blocked;
164 sigfillset(&current->blocked);
165 sigdelsetmask(&current->blocked, sigmask(SIGKILL));
166 recalc_sigpending();
167 spin_unlock_irqrestore(&current->sighand->siglock, flags);
168
169 do {
170 sock->sk->sk_allocation = GFP_NOIO;
171 iov.iov_base = buf;
172 iov.iov_len = size;
173 msg.msg_name = NULL;
174 msg.msg_namelen = 0;
175 msg.msg_control = NULL;
176 msg.msg_controllen = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177 msg.msg_flags = msg_flags | MSG_NOSIGNAL;
178
179 if (send)
180 result = kernel_sendmsg(sock, &msg, &iov, 1, size);
181 else
182 result = kernel_recvmsg(sock, &msg, &iov, 1, size, 0);
183
184 if (signal_pending(current)) {
185 siginfo_t info;
186 spin_lock_irqsave(&current->sighand->siglock, flags);
187 printk(KERN_WARNING "nbd (pid %d: %s) got signal %d\n",
188 current->pid, current->comm,
189 dequeue_signal(current, &current->blocked, &info));
190 spin_unlock_irqrestore(&current->sighand->siglock, flags);
191 result = -EINTR;
192 break;
193 }
194
195 if (result <= 0) {
196 if (result == 0)
197 result = -EPIPE; /* short read */
198 break;
199 }
200 size -= result;
201 buf += result;
202 } while (size > 0);
203
204 spin_lock_irqsave(&current->sighand->siglock, flags);
205 current->blocked = oldset;
206 recalc_sigpending();
207 spin_unlock_irqrestore(&current->sighand->siglock, flags);
208
209 return result;
210}
211
212static inline int sock_send_bvec(struct socket *sock, struct bio_vec *bvec,
213 int flags)
214{
215 int result;
216 void *kaddr = kmap(bvec->bv_page);
217 result = sock_xmit(sock, 1, kaddr + bvec->bv_offset, bvec->bv_len,
218 flags);
219 kunmap(bvec->bv_page);
220 return result;
221}
222
223static int nbd_send_req(struct nbd_device *lo, struct request *req)
224{
225 int result, i, flags;
226 struct nbd_request request;
227 unsigned long size = req->nr_sectors << 9;
228 struct socket *sock = lo->sock;
229
230 request.magic = htonl(NBD_REQUEST_MAGIC);
231 request.type = htonl(nbd_cmd(req));
232 request.from = cpu_to_be64((u64) req->sector << 9);
233 request.len = htonl(size);
234 memcpy(request.handle, &req, sizeof(req));
235
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%luB)\n",
237 lo->disk->disk_name, req,
238 nbdcmd_to_ascii(nbd_cmd(req)),
239 (unsigned long long)req->sector << 9,
240 req->nr_sectors << 9);
241 result = sock_xmit(sock, 1, &request, sizeof(request),
242 (nbd_cmd(req) == NBD_CMD_WRITE)? MSG_MORE: 0);
243 if (result <= 0) {
244 printk(KERN_ERR "%s: Send control failed (result %d)\n",
245 lo->disk->disk_name, result);
246 goto error_out;
247 }
248
249 if (nbd_cmd(req) == NBD_CMD_WRITE) {
250 struct bio *bio;
251 /*
252 * we are really probing at internals to determine
253 * whether to set MSG_MORE or not...
254 */
255 rq_for_each_bio(bio, req) {
256 struct bio_vec *bvec;
257 bio_for_each_segment(bvec, bio, i) {
258 flags = 0;
259 if ((i < (bio->bi_vcnt - 1)) || bio->bi_next)
260 flags = MSG_MORE;
261 dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n",
262 lo->disk->disk_name, req,
263 bvec->bv_len);
264 result = sock_send_bvec(sock, bvec, flags);
265 if (result <= 0) {
266 printk(KERN_ERR "%s: Send data failed (result %d)\n",
267 lo->disk->disk_name,
268 result);
269 goto error_out;
270 }
271 }
272 }
273 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 return 0;
275
276error_out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277 return 1;
278}
279
280static struct request *nbd_find_request(struct nbd_device *lo, char *handle)
281{
282 struct request *req;
283 struct list_head *tmp;
284 struct request *xreq;
Herbert Xu4b2f0262006-01-06 00:09:47 -0800285 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286
287 memcpy(&xreq, handle, sizeof(xreq));
288
Herbert Xu4b2f0262006-01-06 00:09:47 -0800289 err = wait_event_interruptible(lo->active_wq, lo->active_req != xreq);
290 if (unlikely(err))
291 goto out;
292
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 spin_lock(&lo->queue_lock);
294 list_for_each(tmp, &lo->queue_head) {
295 req = list_entry(tmp, struct request, queuelist);
296 if (req != xreq)
297 continue;
298 list_del_init(&req->queuelist);
299 spin_unlock(&lo->queue_lock);
300 return req;
301 }
302 spin_unlock(&lo->queue_lock);
Herbert Xu4b2f0262006-01-06 00:09:47 -0800303
304 err = -ENOENT;
305
306out:
307 return ERR_PTR(err);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308}
309
310static inline int sock_recv_bvec(struct socket *sock, struct bio_vec *bvec)
311{
312 int result;
313 void *kaddr = kmap(bvec->bv_page);
314 result = sock_xmit(sock, 0, kaddr + bvec->bv_offset, bvec->bv_len,
315 MSG_WAITALL);
316 kunmap(bvec->bv_page);
317 return result;
318}
319
320/* NULL returned = something went wrong, inform userspace */
321static struct request *nbd_read_stat(struct nbd_device *lo)
322{
323 int result;
324 struct nbd_reply reply;
325 struct request *req;
326 struct socket *sock = lo->sock;
327
328 reply.magic = 0;
329 result = sock_xmit(sock, 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 req = nbd_find_request(lo, reply.handle);
Herbert Xu4b2f0262006-01-06 00:09:47 -0800336 if (unlikely(IS_ERR(req))) {
337 result = PTR_ERR(req);
338 if (result != -ENOENT)
339 goto harderror;
340
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341 printk(KERN_ERR "%s: Unexpected reply (%p)\n",
342 lo->disk->disk_name, reply.handle);
343 result = -EBADR;
344 goto harderror;
345 }
346
347 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) {
348 printk(KERN_ERR "%s: Wrong magic (0x%lx)\n",
349 lo->disk->disk_name,
350 (unsigned long)ntohl(reply.magic));
351 result = -EPROTO;
352 goto harderror;
353 }
354 if (ntohl(reply.error)) {
355 printk(KERN_ERR "%s: Other side returned error (%d)\n",
356 lo->disk->disk_name, ntohl(reply.error));
357 req->errors++;
358 return req;
359 }
360
361 dprintk(DBG_RX, "%s: request %p: got reply\n",
362 lo->disk->disk_name, req);
363 if (nbd_cmd(req) == NBD_CMD_READ) {
364 int i;
365 struct bio *bio;
366 rq_for_each_bio(bio, req) {
367 struct bio_vec *bvec;
368 bio_for_each_segment(bvec, bio, i) {
369 result = sock_recv_bvec(sock, bvec);
370 if (result <= 0) {
371 printk(KERN_ERR "%s: Receive data failed (result %d)\n",
372 lo->disk->disk_name,
373 result);
374 goto harderror;
375 }
376 dprintk(DBG_RX, "%s: request %p: got %d bytes data\n",
377 lo->disk->disk_name, req, bvec->bv_len);
378 }
379 }
380 }
381 return req;
382harderror:
383 lo->harderror = result;
384 return NULL;
385}
386
387static void nbd_do_it(struct nbd_device *lo)
388{
389 struct request *req;
390
391 BUG_ON(lo->magic != LO_MAGIC);
392
393 while ((req = nbd_read_stat(lo)) != NULL)
394 nbd_end_request(req);
395 return;
396}
397
398static void nbd_clear_que(struct nbd_device *lo)
399{
400 struct request *req;
401
402 BUG_ON(lo->magic != LO_MAGIC);
403
Herbert Xu4b2f0262006-01-06 00:09:47 -0800404 /*
405 * Because we have set lo->sock to NULL under the tx_lock, all
406 * modifications to the list must have completed by now. For
407 * the same reason, the active_req must be NULL.
408 *
409 * As a consequence, we don't need to take the spin lock while
410 * purging the list here.
411 */
412 BUG_ON(lo->sock);
413 BUG_ON(lo->active_req);
414
415 while (!list_empty(&lo->queue_head)) {
416 req = list_entry(lo->queue_head.next, struct request,
417 queuelist);
418 list_del_init(&req->queuelist);
419 req->errors++;
420 nbd_end_request(req);
421 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422}
423
424/*
425 * We always wait for result of write, for now. It would be nice to make it optional
426 * in future
427 * if ((req->cmd == WRITE) && (lo->flags & NBD_WRITE_NOCHK))
428 * { printk( "Warning: Ignoring result!\n"); nbd_end_request( req ); }
429 */
430
431static void do_nbd_request(request_queue_t * q)
432{
433 struct request *req;
434
435 while ((req = elv_next_request(q)) != NULL) {
436 struct nbd_device *lo;
437
438 blkdev_dequeue_request(req);
439 dprintk(DBG_BLKDEV, "%s: request %p: dequeued (flags=%lx)\n",
440 req->rq_disk->disk_name, req, req->flags);
441
442 if (!(req->flags & REQ_CMD))
443 goto error_out;
444
445 lo = req->rq_disk->private_data;
446
447 BUG_ON(lo->magic != LO_MAGIC);
448
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449 nbd_cmd(req) = NBD_CMD_READ;
450 if (rq_data_dir(req) == WRITE) {
451 nbd_cmd(req) = NBD_CMD_WRITE;
452 if (lo->flags & NBD_READ_ONLY) {
453 printk(KERN_ERR "%s: Write on read-only\n",
454 lo->disk->disk_name);
455 goto error_out;
456 }
457 }
458
459 req->errors = 0;
460 spin_unlock_irq(q->queue_lock);
461
Herbert Xu4b2f0262006-01-06 00:09:47 -0800462 down(&lo->tx_lock);
463 if (unlikely(!lo->sock)) {
464 up(&lo->tx_lock);
465 printk(KERN_ERR "%s: Attempted send on closed socket\n",
466 lo->disk->disk_name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467 req->errors++;
468 nbd_end_request(req);
469 spin_lock_irq(q->queue_lock);
470 continue;
471 }
472
Herbert Xu4b2f0262006-01-06 00:09:47 -0800473 lo->active_req = req;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700474
475 if (nbd_send_req(lo, req) != 0) {
476 printk(KERN_ERR "%s: Request send failed\n",
477 lo->disk->disk_name);
Herbert Xu4b2f0262006-01-06 00:09:47 -0800478 req->errors++;
479 nbd_end_request(req);
480 } else {
481 spin_lock(&lo->queue_lock);
482 list_add(&req->queuelist, &lo->queue_head);
483 spin_unlock(&lo->queue_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484 }
485
Herbert Xu4b2f0262006-01-06 00:09:47 -0800486 lo->active_req = NULL;
487 up(&lo->tx_lock);
488 wake_up_all(&lo->active_wq);
489
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490 spin_lock_irq(q->queue_lock);
491 continue;
492
493error_out:
494 req->errors++;
495 spin_unlock(q->queue_lock);
496 nbd_end_request(req);
497 spin_lock(q->queue_lock);
498 }
499 return;
500}
501
502static int nbd_ioctl(struct inode *inode, struct file *file,
503 unsigned int cmd, unsigned long arg)
504{
505 struct nbd_device *lo = inode->i_bdev->bd_disk->private_data;
506 int error;
507 struct request sreq ;
508
509 if (!capable(CAP_SYS_ADMIN))
510 return -EPERM;
511
512 BUG_ON(lo->magic != LO_MAGIC);
513
514 /* Anyone capable of this syscall can do *real bad* things */
515 dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n",
516 lo->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg);
517
518 switch (cmd) {
519 case NBD_DISCONNECT:
520 printk(KERN_INFO "%s: NBD_DISCONNECT\n", lo->disk->disk_name);
521 sreq.flags = REQ_SPECIAL;
522 nbd_cmd(&sreq) = NBD_CMD_DISC;
523 /*
524 * Set these to sane values in case server implementation
525 * fails to check the request type first and also to keep
526 * debugging output cleaner.
527 */
528 sreq.sector = 0;
529 sreq.nr_sectors = 0;
530 if (!lo->sock)
531 return -EINVAL;
532 nbd_send_req(lo, &sreq);
533 return 0;
534
535 case NBD_CLEAR_SOCK:
536 error = 0;
537 down(&lo->tx_lock);
538 lo->sock = NULL;
539 up(&lo->tx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540 file = lo->file;
541 lo->file = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700542 nbd_clear_que(lo);
Herbert Xu4b2f0262006-01-06 00:09:47 -0800543 BUG_ON(!list_empty(&lo->queue_head));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544 if (file)
545 fput(file);
546 return error;
547 case NBD_SET_SOCK:
548 if (lo->file)
549 return -EBUSY;
550 error = -EINVAL;
551 file = fget(arg);
552 if (file) {
553 inode = file->f_dentry->d_inode;
554 if (S_ISSOCK(inode->i_mode)) {
555 lo->file = file;
556 lo->sock = SOCKET_I(inode);
557 error = 0;
558 } else {
559 fput(file);
560 }
561 }
562 return error;
563 case NBD_SET_BLKSIZE:
564 lo->blksize = arg;
565 lo->bytesize &= ~(lo->blksize-1);
566 inode->i_bdev->bd_inode->i_size = lo->bytesize;
567 set_blocksize(inode->i_bdev, lo->blksize);
568 set_capacity(lo->disk, lo->bytesize >> 9);
569 return 0;
570 case NBD_SET_SIZE:
571 lo->bytesize = arg & ~(lo->blksize-1);
572 inode->i_bdev->bd_inode->i_size = lo->bytesize;
573 set_blocksize(inode->i_bdev, lo->blksize);
574 set_capacity(lo->disk, lo->bytesize >> 9);
575 return 0;
576 case NBD_SET_SIZE_BLOCKS:
577 lo->bytesize = ((u64) arg) * lo->blksize;
578 inode->i_bdev->bd_inode->i_size = lo->bytesize;
579 set_blocksize(inode->i_bdev, lo->blksize);
580 set_capacity(lo->disk, lo->bytesize >> 9);
581 return 0;
582 case NBD_DO_IT:
583 if (!lo->file)
584 return -EINVAL;
585 nbd_do_it(lo);
586 /* on return tidy up in case we have a signal */
587 /* Forcibly shutdown the socket causing all listeners
588 * to error
589 *
590 * FIXME: This code is duplicated from sys_shutdown, but
591 * there should be a more generic interface rather than
592 * calling socket ops directly here */
593 down(&lo->tx_lock);
594 if (lo->sock) {
595 printk(KERN_WARNING "%s: shutting down socket\n",
596 lo->disk->disk_name);
597 lo->sock->ops->shutdown(lo->sock,
598 SEND_SHUTDOWN|RCV_SHUTDOWN);
599 lo->sock = NULL;
600 }
601 up(&lo->tx_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602 file = lo->file;
603 lo->file = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700604 nbd_clear_que(lo);
605 printk(KERN_WARNING "%s: queue cleared\n", lo->disk->disk_name);
606 if (file)
607 fput(file);
608 return lo->harderror;
609 case NBD_CLEAR_QUE:
Herbert Xu4b2f0262006-01-06 00:09:47 -0800610 /*
611 * This is for compatibility only. The queue is always cleared
612 * by NBD_DO_IT or NBD_CLEAR_SOCK.
613 */
614 BUG_ON(!lo->sock && !list_empty(&lo->queue_head));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615 return 0;
616 case NBD_PRINT_DEBUG:
617 printk(KERN_INFO "%s: next = %p, prev = %p, head = %p\n",
618 inode->i_bdev->bd_disk->disk_name,
619 lo->queue_head.next, lo->queue_head.prev,
620 &lo->queue_head);
621 return 0;
622 }
623 return -EINVAL;
624}
625
626static struct block_device_operations nbd_fops =
627{
628 .owner = THIS_MODULE,
629 .ioctl = nbd_ioctl,
630};
631
632/*
633 * And here should be modules and kernel interface
634 * (Just smiley confuses emacs :-)
635 */
636
637static int __init nbd_init(void)
638{
639 int err = -ENOMEM;
640 int i;
641
642 if (sizeof(struct nbd_request) != 28) {
643 printk(KERN_CRIT "nbd: sizeof nbd_request needs to be 28 in order to work!\n" );
644 return -EIO;
645 }
646
Lars Marowsky-Bree40be0c22005-05-01 08:59:07 -0700647 if (nbds_max > MAX_NBD) {
648 printk(KERN_CRIT "nbd: cannot allocate more than %u nbds; %u requested.\n", MAX_NBD,
649 nbds_max);
650 return -EINVAL;
651 }
652
653 for (i = 0; i < nbds_max; i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654 struct gendisk *disk = alloc_disk(1);
655 if (!disk)
656 goto out;
657 nbd_dev[i].disk = disk;
658 /*
659 * The new linux 2.5 block layer implementation requires
660 * every gendisk to have its very own request_queue struct.
661 * These structs are big so we dynamically allocate them.
662 */
663 disk->queue = blk_init_queue(do_nbd_request, &nbd_lock);
664 if (!disk->queue) {
665 put_disk(disk);
666 goto out;
667 }
668 }
669
670 if (register_blkdev(NBD_MAJOR, "nbd")) {
671 err = -EIO;
672 goto out;
673 }
674
675 printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR);
676 dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags);
677
678 devfs_mk_dir("nbd");
Lars Marowsky-Bree40be0c22005-05-01 08:59:07 -0700679 for (i = 0; i < nbds_max; i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700680 struct gendisk *disk = nbd_dev[i].disk;
681 nbd_dev[i].file = NULL;
682 nbd_dev[i].magic = LO_MAGIC;
683 nbd_dev[i].flags = 0;
684 spin_lock_init(&nbd_dev[i].queue_lock);
685 INIT_LIST_HEAD(&nbd_dev[i].queue_head);
686 init_MUTEX(&nbd_dev[i].tx_lock);
Herbert Xu4b2f0262006-01-06 00:09:47 -0800687 init_waitqueue_head(&nbd_dev[i].active_wq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688 nbd_dev[i].blksize = 1024;
689 nbd_dev[i].bytesize = 0x7ffffc00ULL << 10; /* 2TB */
690 disk->major = NBD_MAJOR;
691 disk->first_minor = i;
692 disk->fops = &nbd_fops;
693 disk->private_data = &nbd_dev[i];
694 disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO;
695 sprintf(disk->disk_name, "nbd%d", i);
696 sprintf(disk->devfs_name, "nbd/%d", i);
697 set_capacity(disk, 0x7ffffc00ULL << 1); /* 2 TB */
698 add_disk(disk);
699 }
700
701 return 0;
702out:
703 while (i--) {
704 blk_cleanup_queue(nbd_dev[i].disk->queue);
705 put_disk(nbd_dev[i].disk);
706 }
707 return err;
708}
709
710static void __exit nbd_cleanup(void)
711{
712 int i;
Lars Marowsky-Bree40be0c22005-05-01 08:59:07 -0700713 for (i = 0; i < nbds_max; i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714 struct gendisk *disk = nbd_dev[i].disk;
Lars Marowsky-Bree40be0c22005-05-01 08:59:07 -0700715 nbd_dev[i].magic = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700716 if (disk) {
717 del_gendisk(disk);
718 blk_cleanup_queue(disk->queue);
719 put_disk(disk);
720 }
721 }
722 devfs_remove("nbd");
723 unregister_blkdev(NBD_MAJOR, "nbd");
724 printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR);
725}
726
727module_init(nbd_init);
728module_exit(nbd_cleanup);
729
730MODULE_DESCRIPTION("Network Block Device");
731MODULE_LICENSE("GPL");
732
Lars Marowsky-Bree40be0c22005-05-01 08:59:07 -0700733module_param(nbds_max, int, 0444);
734MODULE_PARM_DESC(nbds_max, "How many network block devices to initialize.");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735#ifndef NDEBUG
736module_param(debugflags, int, 0644);
737MODULE_PARM_DESC(debugflags, "flags for controlling debug output");
738#endif