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 55 static unsigned int debugflags; 56 #endif /* NDEBUG */ 57 58 static unsigned int nbds_max = 16; 59 static struct nbd_device *nbd_dev; 60 static 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 */ 72 static DEFINE_SPINLOCK(nbd_lock); 73 74 #ifndef NDEBUG 75 static 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 93 static 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 */ 103 104 static 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 } 117 118 static 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 } 136 137 static 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 */ 149 static 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 } 220 221 static 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 */ 233 static 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; 281 282 error_out: 283 return -EIO; 284 } 285 286 static 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; 307 308 out: 309 return ERR_PTR(err); 310 } 311 312 static 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 */ 323 static 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; 382 harderror: 383 nbd->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 *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 } 423 424 static 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 } 449 450 451 static void nbd_handle_req(struct nbd_device *nbd, 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 (nbd->flags & NBD_READ_ONLY) { 460 dev_err(disk_to_dev(nbd->disk), 461 "Write on read-only\n"); 462 goto error_out; 463 } 464 } 465 466 req->errors = 0; 467 468 mutex_lock(&nbd->tx_lock); 469 if (unlikely(!nbd->sock)) { 470 mutex_unlock(&nbd->tx_lock); 471 dev_err(disk_to_dev(nbd->disk), 472 "Attempted send on closed socket\n"); 473 goto error_out; 474 } 475 476 nbd->active_req = req; 477 478 if (nbd_send_req(nbd, req) != 0) { 479 dev_err(disk_to_dev(nbd->disk), "Request send failed\n"); 480 req->errors++; 481 nbd_end_request(req); 482 } else { 483 spin_lock(&nbd->queue_lock); 484 list_add(&req->queuelist, &nbd->queue_head); 485 spin_unlock(&nbd->queue_lock); 486 } 487 488 nbd->active_req = NULL; 489 mutex_unlock(&nbd->tx_lock); 490 wake_up_all(&nbd->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 *nbd = data; 502 struct request *req; 503 504 set_user_nice(current, -20); 505 while (!kthread_should_stop() || !list_empty(&nbd->waiting_queue)) { 506 /* wait for something to do */ 507 wait_event_interruptible(nbd->waiting_wq, 508 kthread_should_stop() || 509 !list_empty(&nbd->waiting_queue)); 510 511 /* extract request */ 512 if (list_empty(&nbd->waiting_queue)) 513 continue; 514 515 spin_lock_irq(&nbd->queue_lock); 516 req = list_entry(nbd->waiting_queue.next, struct request, 517 queuelist); 518 list_del_init(&req->queuelist); 519 spin_unlock_irq(&nbd->queue_lock); 520 521 /* handle request */ 522 nbd_handle_req(nbd, 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) && (nbd->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 *nbd; 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 nbd = req->rq_disk->private_data; 547 548 BUG_ON(nbd->magic != NBD_MAGIC); 549 550 if (unlikely(!nbd->sock)) { 551 dev_err(disk_to_dev(nbd->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(&nbd->queue_lock); 560 list_add_tail(&req->queuelist, &nbd->waiting_queue); 561 spin_unlock_irq(&nbd->queue_lock); 562 563 wake_up(&nbd->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 *nbd, 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(nbd->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 (!nbd->sock) 584 return -EINVAL; 585 nbd_send_req(nbd, &sreq); 586 return 0; 587 } 588 589 case NBD_CLEAR_SOCK: { 590 struct file *file; 591 592 nbd->sock = NULL; 593 file = nbd->file; 594 nbd->file = NULL; 595 nbd_clear_que(nbd); 596 BUG_ON(!list_empty(&nbd->queue_head)); 597 if (file) 598 fput(file); 599 return 0; 600 } 601 602 case NBD_SET_SOCK: { 603 struct file *file; 604 if (nbd->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 nbd->file = file; 611 nbd->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 nbd->blksize = arg; 624 nbd->bytesize &= ~(nbd->blksize-1); 625 bdev->bd_inode->i_size = nbd->bytesize; 626 set_blocksize(bdev, nbd->blksize); 627 set_capacity(nbd->disk, nbd->bytesize >> 9); 628 return 0; 629 630 case NBD_SET_SIZE: 631 nbd->bytesize = arg & ~(nbd->blksize-1); 632 bdev->bd_inode->i_size = nbd->bytesize; 633 set_blocksize(bdev, nbd->blksize); 634 set_capacity(nbd->disk, nbd->bytesize >> 9); 635 return 0; 636 637 case NBD_SET_TIMEOUT: 638 nbd->xmit_timeout = arg * HZ; 639 return 0; 640 641 case NBD_SET_SIZE_BLOCKS: 642 nbd->bytesize = ((u64) arg) * nbd->blksize; 643 bdev->bd_inode->i_size = nbd->bytesize; 644 set_blocksize(bdev, nbd->blksize); 645 set_capacity(nbd->disk, nbd->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 (nbd->pid) 654 return -EBUSY; 655 if (!nbd->file) 656 return -EINVAL; 657 658 mutex_unlock(&nbd->tx_lock); 659 660 thread = kthread_create(nbd_thread, nbd, nbd->disk->disk_name); 661 if (IS_ERR(thread)) { 662 mutex_lock(&nbd->tx_lock); 663 return PTR_ERR(thread); 664 } 665 wake_up_process(thread); 666 error = nbd_do_it(nbd); 667 kthread_stop(thread); 668 669 mutex_lock(&nbd->tx_lock); 670 if (error) 671 return error; 672 sock_shutdown(nbd, 0); 673 file = nbd->file; 674 nbd->file = NULL; 675 nbd_clear_que(nbd); 676 dev_warn(disk_to_dev(nbd->disk), "queue cleared\n"); 677 if (file) 678 fput(file); 679 nbd->bytesize = 0; 680 bdev->bd_inode->i_size = 0; 681 set_capacity(nbd->disk, 0); 682 if (max_part > 0) 683 ioctl_by_bdev(bdev, BLKRRPART, 0); 684 return nbd->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(!nbd->sock && !list_empty(&nbd->queue_head)); 693 return 0; 694 695 case NBD_PRINT_DEBUG: 696 dev_info(disk_to_dev(nbd->disk), 697 "next = %p, prev = %p, head = %p\n", 698 nbd->queue_head.next, nbd->queue_head.prev, 699 &nbd->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 *nbd = bdev->bd_disk->private_data; 709 int error; 710 711 if (!capable(CAP_SYS_ADMIN)) 712 return -EPERM; 713 714 BUG_ON(nbd->magic != NBD_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 nbd->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg); 719 720 mutex_lock(&nbd->tx_lock); 721 error = __nbd_ioctl(bdev, nbd, cmd, arg); 722 mutex_unlock(&nbd->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 = NBD_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 868