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Commit | Line | Data |
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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 | |
56 | static unsigned int debugflags; | |
57 | #endif /* NDEBUG */ | |
58 | ||
59 | static unsigned int nbds_max = 16; | |
60 | static struct nbd_device *nbd_dev; | |
61 | static 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 | */ | |
73 | static DEFINE_SPINLOCK(nbd_lock); | |
74 | ||
75 | #ifndef NDEBUG | |
76 | static 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 | ||
94 | static 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 | ||
105 | static 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 | ||
119 | static 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 | dev_warn(disk_to_dev(lo->disk), "shutting down socket\n"); | |
131 | kernel_sock_shutdown(lo->sock, SHUT_RDWR); | |
132 | lo->sock = NULL; | |
133 | } | |
134 | if (lock) | |
135 | mutex_unlock(&lo->tx_lock); | |
136 | } | |
137 | ||
138 | static void nbd_xmit_timeout(unsigned long arg) | |
139 | { | |
140 | struct task_struct *task = (struct task_struct *)arg; | |
141 | ||
142 | printk(KERN_WARNING "nbd: killing hung xmit (%s, pid: %d)\n", | |
143 | task->comm, task->pid); | |
144 | force_sig(SIGKILL, task); | |
145 | } | |
146 | ||
147 | /* | |
148 | * Send or receive packet. | |
149 | */ | |
150 | static int sock_xmit(struct nbd_device *lo, int send, void *buf, int size, | |
151 | int msg_flags) | |
152 | { | |
153 | struct socket *sock = lo->sock; | |
154 | int result; | |
155 | struct msghdr msg; | |
156 | struct kvec iov; | |
157 | sigset_t blocked, oldset; | |
158 | ||
159 | if (unlikely(!sock)) { | |
160 | dev_err(disk_to_dev(lo->disk), | |
161 | "Attempted %s on closed socket in sock_xmit\n", | |
162 | (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 | ||
222 | static 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 */ | |
233 | static 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 | dev_err(disk_to_dev(lo->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 | lo->disk->disk_name, req, bvec->bv_len); | |
271 | result = sock_send_bvec(lo, bvec, flags); | |
272 | if (result <= 0) { | |
273 | dev_err(disk_to_dev(lo->disk), | |
274 | "Send data failed (result %d)\n", | |
275 | result); | |
276 | goto error_out; | |
277 | } | |
278 | } | |
279 | } | |
280 | return 0; | |
281 | ||
282 | error_out: | |
283 | return -EIO; | |
284 | } | |
285 | ||
286 | static struct request *nbd_find_request(struct nbd_device *lo, | |
287 | struct request *xreq) | |
288 | { | |
289 | struct request *req, *tmp; | |
290 | int err; | |
291 | ||
292 | err = wait_event_interruptible(lo->active_wq, lo->active_req != xreq); | |
293 | if (unlikely(err)) | |
294 | goto out; | |
295 | ||
296 | spin_lock(&lo->queue_lock); | |
297 | list_for_each_entry_safe(req, tmp, &lo->queue_head, queuelist) { | |
298 | if (req != xreq) | |
299 | continue; | |
300 | list_del_init(&req->queuelist); | |
301 | spin_unlock(&lo->queue_lock); | |
302 | return req; | |
303 | } | |
304 | spin_unlock(&lo->queue_lock); | |
305 | ||
306 | err = -ENOENT; | |
307 | ||
308 | out: | |
309 | return ERR_PTR(err); | |
310 | } | |
311 | ||
312 | static inline int sock_recv_bvec(struct nbd_device *lo, struct bio_vec *bvec) | |
313 | { | |
314 | int result; | |
315 | void *kaddr = kmap(bvec->bv_page); | |
316 | result = sock_xmit(lo, 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 */ | |
323 | static struct request *nbd_read_stat(struct nbd_device *lo) | |
324 | { | |
325 | int result; | |
326 | struct nbd_reply reply; | |
327 | struct request *req; | |
328 | ||
329 | reply.magic = 0; | |
330 | result = sock_xmit(lo, 0, &reply, sizeof(reply), MSG_WAITALL); | |
331 | if (result <= 0) { | |
332 | dev_err(disk_to_dev(lo->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(lo->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(lo, *(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(lo->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(lo->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 | 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 | dev_err(disk_to_dev(lo->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 | lo->disk->disk_name, req, bvec->bv_len); | |
379 | } | |
380 | } | |
381 | return req; | |
382 | harderror: | |
383 | lo->harderror = result; | |
384 | return NULL; | |
385 | } | |
386 | ||
387 | static 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 | ||
396 | static struct device_attribute pid_attr = { | |
397 | .attr = { .name = "pid", .mode = S_IRUGO}, | |
398 | .show = pid_show, | |
399 | }; | |
400 | ||
401 | static 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 = task_pid_nr(current); | |
409 | ret = device_create_file(disk_to_dev(lo->disk), &pid_attr); | |
410 | if (ret) { | |
411 | dev_err(disk_to_dev(lo->disk), "device_create_file failed!\n"); | |
412 | lo->pid = 0; | |
413 | return ret; | |
414 | } | |
415 | ||
416 | while ((req = nbd_read_stat(lo)) != NULL) | |
417 | nbd_end_request(req); | |
418 | ||
419 | device_remove_file(disk_to_dev(lo->disk), &pid_attr); | |
420 | lo->pid = 0; | |
421 | return 0; | |
422 | } | |
423 | ||
424 | static 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 | ||
451 | static 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 | dev_err(disk_to_dev(lo->disk), | |
461 | "Write on read-only\n"); | |
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 | dev_err(disk_to_dev(lo->disk), | |
472 | "Attempted send on closed socket\n"); | |
473 | goto error_out; | |
474 | } | |
475 | ||
476 | lo->active_req = req; | |
477 | ||
478 | if (nbd_send_req(lo, req) != 0) { | |
479 | dev_err(disk_to_dev(lo->disk), "Request send failed\n"); | |
480 | req->errors++; | |
481 | nbd_end_request(req); | |
482 | } else { | |
483 | spin_lock(&lo->queue_lock); | |
484 | list_add(&req->queuelist, &lo->queue_head); | |
485 | spin_unlock(&lo->queue_lock); | |
486 | } | |
487 | ||
488 | lo->active_req = NULL; | |
489 | mutex_unlock(&lo->tx_lock); | |
490 | wake_up_all(&lo->active_wq); | |
491 | ||
492 | return; | |
493 | ||
494 | error_out: | |
495 | req->errors++; | |
496 | nbd_end_request(req); | |
497 | } | |
498 | ||
499 | static int nbd_thread(void *data) | |
500 | { | |
501 | struct nbd_device *lo = data; | |
502 | struct request *req; | |
503 | ||
504 | set_user_nice(current, -20); | |
505 | while (!kthread_should_stop() || !list_empty(&lo->waiting_queue)) { | |
506 | /* wait for something to do */ | |
507 | wait_event_interruptible(lo->waiting_wq, | |
508 | kthread_should_stop() || | |
509 | !list_empty(&lo->waiting_queue)); | |
510 | ||
511 | /* extract request */ | |
512 | if (list_empty(&lo->waiting_queue)) | |
513 | continue; | |
514 | ||
515 | spin_lock_irq(&lo->queue_lock); | |
516 | req = list_entry(lo->waiting_queue.next, struct request, | |
517 | queuelist); | |
518 | list_del_init(&req->queuelist); | |
519 | spin_unlock_irq(&lo->queue_lock); | |
520 | ||
521 | /* handle request */ | |
522 | nbd_handle_req(lo, req); | |
523 | } | |
524 | return 0; | |
525 | } | |
526 | ||
527 | /* | |
528 | * We always wait for result of write, for now. It would be nice to make it optional | |
529 | * in future | |
530 | * if ((rq_data_dir(req) == WRITE) && (lo->flags & NBD_WRITE_NOCHK)) | |
531 | * { printk( "Warning: Ignoring result!\n"); nbd_end_request( req ); } | |
532 | */ | |
533 | ||
534 | static void do_nbd_request(struct request_queue *q) | |
535 | { | |
536 | struct request *req; | |
537 | ||
538 | while ((req = blk_fetch_request(q)) != NULL) { | |
539 | struct nbd_device *lo; | |
540 | ||
541 | spin_unlock_irq(q->queue_lock); | |
542 | ||
543 | dprintk(DBG_BLKDEV, "%s: request %p: dequeued (flags=%x)\n", | |
544 | req->rq_disk->disk_name, req, req->cmd_type); | |
545 | ||
546 | lo = req->rq_disk->private_data; | |
547 | ||
548 | BUG_ON(lo->magic != LO_MAGIC); | |
549 | ||
550 | if (unlikely(!lo->sock)) { | |
551 | dev_err(disk_to_dev(lo->disk), | |
552 | "Attempted send on closed socket\n"); | |
553 | req->errors++; | |
554 | nbd_end_request(req); | |
555 | spin_lock_irq(q->queue_lock); | |
556 | continue; | |
557 | } | |
558 | ||
559 | spin_lock_irq(&lo->queue_lock); | |
560 | list_add_tail(&req->queuelist, &lo->waiting_queue); | |
561 | spin_unlock_irq(&lo->queue_lock); | |
562 | ||
563 | wake_up(&lo->waiting_wq); | |
564 | ||
565 | spin_lock_irq(q->queue_lock); | |
566 | } | |
567 | } | |
568 | ||
569 | /* Must be called with tx_lock held */ | |
570 | ||
571 | static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *lo, | |
572 | unsigned int cmd, unsigned long arg) | |
573 | { | |
574 | switch (cmd) { | |
575 | case NBD_DISCONNECT: { | |
576 | struct request sreq; | |
577 | ||
578 | dev_info(disk_to_dev(lo->disk), "NBD_DISCONNECT\n"); | |
579 | ||
580 | blk_rq_init(NULL, &sreq); | |
581 | sreq.cmd_type = REQ_TYPE_SPECIAL; | |
582 | nbd_cmd(&sreq) = NBD_CMD_DISC; | |
583 | if (!lo->sock) | |
584 | return -EINVAL; | |
585 | nbd_send_req(lo, &sreq); | |
586 | return 0; | |
587 | } | |
588 | ||
589 | case NBD_CLEAR_SOCK: { | |
590 | struct file *file; | |
591 | ||
592 | lo->sock = NULL; | |
593 | file = lo->file; | |
594 | lo->file = NULL; | |
595 | nbd_clear_que(lo); | |
596 | BUG_ON(!list_empty(&lo->queue_head)); | |
597 | if (file) | |
598 | fput(file); | |
599 | return 0; | |
600 | } | |
601 | ||
602 | case NBD_SET_SOCK: { | |
603 | struct file *file; | |
604 | if (lo->file) | |
605 | return -EBUSY; | |
606 | file = fget(arg); | |
607 | if (file) { | |
608 | struct inode *inode = file->f_path.dentry->d_inode; | |
609 | if (S_ISSOCK(inode->i_mode)) { | |
610 | lo->file = file; | |
611 | lo->sock = SOCKET_I(inode); | |
612 | if (max_part > 0) | |
613 | bdev->bd_invalidated = 1; | |
614 | return 0; | |
615 | } else { | |
616 | fput(file); | |
617 | } | |
618 | } | |
619 | return -EINVAL; | |
620 | } | |
621 | ||
622 | case NBD_SET_BLKSIZE: | |
623 | lo->blksize = arg; | |
624 | lo->bytesize &= ~(lo->blksize-1); | |
625 | bdev->bd_inode->i_size = lo->bytesize; | |
626 | set_blocksize(bdev, lo->blksize); | |
627 | set_capacity(lo->disk, lo->bytesize >> 9); | |
628 | return 0; | |
629 | ||
630 | case NBD_SET_SIZE: | |
631 | lo->bytesize = arg & ~(lo->blksize-1); | |
632 | bdev->bd_inode->i_size = lo->bytesize; | |
633 | set_blocksize(bdev, lo->blksize); | |
634 | set_capacity(lo->disk, lo->bytesize >> 9); | |
635 | return 0; | |
636 | ||
637 | case NBD_SET_TIMEOUT: | |
638 | lo->xmit_timeout = arg * HZ; | |
639 | return 0; | |
640 | ||
641 | case NBD_SET_SIZE_BLOCKS: | |
642 | lo->bytesize = ((u64) arg) * lo->blksize; | |
643 | bdev->bd_inode->i_size = lo->bytesize; | |
644 | set_blocksize(bdev, lo->blksize); | |
645 | set_capacity(lo->disk, lo->bytesize >> 9); | |
646 | return 0; | |
647 | ||
648 | case NBD_DO_IT: { | |
649 | struct task_struct *thread; | |
650 | struct file *file; | |
651 | int error; | |
652 | ||
653 | if (lo->pid) | |
654 | return -EBUSY; | |
655 | if (!lo->file) | |
656 | return -EINVAL; | |
657 | ||
658 | mutex_unlock(&lo->tx_lock); | |
659 | ||
660 | thread = kthread_create(nbd_thread, lo, lo->disk->disk_name); | |
661 | if (IS_ERR(thread)) { | |
662 | mutex_lock(&lo->tx_lock); | |
663 | return PTR_ERR(thread); | |
664 | } | |
665 | wake_up_process(thread); | |
666 | error = nbd_do_it(lo); | |
667 | kthread_stop(thread); | |
668 | ||
669 | mutex_lock(&lo->tx_lock); | |
670 | if (error) | |
671 | return error; | |
672 | sock_shutdown(lo, 0); | |
673 | file = lo->file; | |
674 | lo->file = NULL; | |
675 | nbd_clear_que(lo); | |
676 | dev_warn(disk_to_dev(lo->disk), "queue cleared\n"); | |
677 | if (file) | |
678 | fput(file); | |
679 | lo->bytesize = 0; | |
680 | bdev->bd_inode->i_size = 0; | |
681 | set_capacity(lo->disk, 0); | |
682 | if (max_part > 0) | |
683 | ioctl_by_bdev(bdev, BLKRRPART, 0); | |
684 | return lo->harderror; | |
685 | } | |
686 | ||
687 | case NBD_CLEAR_QUE: | |
688 | /* | |
689 | * This is for compatibility only. The queue is always cleared | |
690 | * by NBD_DO_IT or NBD_CLEAR_SOCK. | |
691 | */ | |
692 | BUG_ON(!lo->sock && !list_empty(&lo->queue_head)); | |
693 | return 0; | |
694 | ||
695 | case NBD_PRINT_DEBUG: | |
696 | dev_info(disk_to_dev(lo->disk), | |
697 | "next = %p, prev = %p, head = %p\n", | |
698 | lo->queue_head.next, lo->queue_head.prev, | |
699 | &lo->queue_head); | |
700 | return 0; | |
701 | } | |
702 | return -ENOTTY; | |
703 | } | |
704 | ||
705 | static int nbd_ioctl(struct block_device *bdev, fmode_t mode, | |
706 | unsigned int cmd, unsigned long arg) | |
707 | { | |
708 | struct nbd_device *lo = bdev->bd_disk->private_data; | |
709 | int error; | |
710 | ||
711 | if (!capable(CAP_SYS_ADMIN)) | |
712 | return -EPERM; | |
713 | ||
714 | BUG_ON(lo->magic != LO_MAGIC); | |
715 | ||
716 | /* Anyone capable of this syscall can do *real bad* things */ | |
717 | dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n", | |
718 | lo->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg); | |
719 | ||
720 | mutex_lock(&lo->tx_lock); | |
721 | error = __nbd_ioctl(bdev, lo, cmd, arg); | |
722 | mutex_unlock(&lo->tx_lock); | |
723 | ||
724 | return error; | |
725 | } | |
726 | ||
727 | static const struct block_device_operations nbd_fops = | |
728 | { | |
729 | .owner = THIS_MODULE, | |
730 | .ioctl = nbd_ioctl, | |
731 | }; | |
732 | ||
733 | /* | |
734 | * And here should be modules and kernel interface | |
735 | * (Just smiley confuses emacs :-) | |
736 | */ | |
737 | ||
738 | static int __init nbd_init(void) | |
739 | { | |
740 | int err = -ENOMEM; | |
741 | int i; | |
742 | int part_shift; | |
743 | ||
744 | BUILD_BUG_ON(sizeof(struct nbd_request) != 28); | |
745 | ||
746 | if (max_part < 0) { | |
747 | printk(KERN_ERR "nbd: max_part must be >= 0\n"); | |
748 | return -EINVAL; | |
749 | } | |
750 | ||
751 | nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL); | |
752 | if (!nbd_dev) | |
753 | return -ENOMEM; | |
754 | ||
755 | part_shift = 0; | |
756 | if (max_part > 0) { | |
757 | part_shift = fls(max_part); | |
758 | ||
759 | /* | |
760 | * Adjust max_part according to part_shift as it is exported | |
761 | * to user space so that user can know the max number of | |
762 | * partition kernel should be able to manage. | |
763 | * | |
764 | * Note that -1 is required because partition 0 is reserved | |
765 | * for the whole disk. | |
766 | */ | |
767 | max_part = (1UL << part_shift) - 1; | |
768 | } | |
769 | ||
770 | if ((1UL << part_shift) > DISK_MAX_PARTS) | |
771 | return -EINVAL; | |
772 | ||
773 | if (nbds_max > 1UL << (MINORBITS - part_shift)) | |
774 | return -EINVAL; | |
775 | ||
776 | for (i = 0; i < nbds_max; i++) { | |
777 | struct gendisk *disk = alloc_disk(1 << part_shift); | |
778 | if (!disk) | |
779 | goto out; | |
780 | nbd_dev[i].disk = disk; | |
781 | /* | |
782 | * The new linux 2.5 block layer implementation requires | |
783 | * every gendisk to have its very own request_queue struct. | |
784 | * These structs are big so we dynamically allocate them. | |
785 | */ | |
786 | disk->queue = blk_init_queue(do_nbd_request, &nbd_lock); | |
787 | if (!disk->queue) { | |
788 | put_disk(disk); | |
789 | goto out; | |
790 | } | |
791 | /* | |
792 | * Tell the block layer that we are not a rotational device | |
793 | */ | |
794 | queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue); | |
795 | } | |
796 | ||
797 | if (register_blkdev(NBD_MAJOR, "nbd")) { | |
798 | err = -EIO; | |
799 | goto out; | |
800 | } | |
801 | ||
802 | printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR); | |
803 | dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags); | |
804 | ||
805 | for (i = 0; i < nbds_max; i++) { | |
806 | struct gendisk *disk = nbd_dev[i].disk; | |
807 | nbd_dev[i].file = NULL; | |
808 | nbd_dev[i].magic = LO_MAGIC; | |
809 | nbd_dev[i].flags = 0; | |
810 | INIT_LIST_HEAD(&nbd_dev[i].waiting_queue); | |
811 | spin_lock_init(&nbd_dev[i].queue_lock); | |
812 | INIT_LIST_HEAD(&nbd_dev[i].queue_head); | |
813 | mutex_init(&nbd_dev[i].tx_lock); | |
814 | init_waitqueue_head(&nbd_dev[i].active_wq); | |
815 | init_waitqueue_head(&nbd_dev[i].waiting_wq); | |
816 | nbd_dev[i].blksize = 1024; | |
817 | nbd_dev[i].bytesize = 0; | |
818 | disk->major = NBD_MAJOR; | |
819 | disk->first_minor = i << part_shift; | |
820 | disk->fops = &nbd_fops; | |
821 | disk->private_data = &nbd_dev[i]; | |
822 | sprintf(disk->disk_name, "nbd%d", i); | |
823 | set_capacity(disk, 0); | |
824 | add_disk(disk); | |
825 | } | |
826 | ||
827 | return 0; | |
828 | out: | |
829 | while (i--) { | |
830 | blk_cleanup_queue(nbd_dev[i].disk->queue); | |
831 | put_disk(nbd_dev[i].disk); | |
832 | } | |
833 | kfree(nbd_dev); | |
834 | return err; | |
835 | } | |
836 | ||
837 | static void __exit nbd_cleanup(void) | |
838 | { | |
839 | int i; | |
840 | for (i = 0; i < nbds_max; i++) { | |
841 | struct gendisk *disk = nbd_dev[i].disk; | |
842 | nbd_dev[i].magic = 0; | |
843 | if (disk) { | |
844 | del_gendisk(disk); | |
845 | blk_cleanup_queue(disk->queue); | |
846 | put_disk(disk); | |
847 | } | |
848 | } | |
849 | unregister_blkdev(NBD_MAJOR, "nbd"); | |
850 | kfree(nbd_dev); | |
851 | printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR); | |
852 | } | |
853 | ||
854 | module_init(nbd_init); | |
855 | module_exit(nbd_cleanup); | |
856 | ||
857 | MODULE_DESCRIPTION("Network Block Device"); | |
858 | MODULE_LICENSE("GPL"); | |
859 | ||
860 | module_param(nbds_max, int, 0444); | |
861 | MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)"); | |
862 | module_param(max_part, int, 0444); | |
863 | MODULE_PARM_DESC(max_part, "number of partitions per device (default: 0)"); | |
864 | #ifndef NDEBUG | |
865 | module_param(debugflags, int, 0644); | |
866 | MODULE_PARM_DESC(debugflags, "flags for controlling debug output"); | |
867 | #endif |