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 unsigned long pflags = current->flags; 158 159 if (unlikely(!sock)) { 160 dev_err(disk_to_dev(nbd->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 current->flags |= PF_MEMALLOC; 172 do { 173 sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC; 174 iov.iov_base = buf; 175 iov.iov_len = size; 176 msg.msg_name = NULL; 177 msg.msg_namelen = 0; 178 msg.msg_control = NULL; 179 msg.msg_controllen = 0; 180 msg.msg_flags = msg_flags | MSG_NOSIGNAL; 181 182 if (send) { 183 struct timer_list ti; 184 185 if (nbd->xmit_timeout) { 186 init_timer(&ti); 187 ti.function = nbd_xmit_timeout; 188 ti.data = (unsigned long)current; 189 ti.expires = jiffies + nbd->xmit_timeout; 190 add_timer(&ti); 191 } 192 result = kernel_sendmsg(sock, &msg, &iov, 1, size); 193 if (nbd->xmit_timeout) 194 del_timer_sync(&ti); 195 } else 196 result = kernel_recvmsg(sock, &msg, &iov, 1, size, 197 msg.msg_flags); 198 199 if (signal_pending(current)) { 200 siginfo_t info; 201 printk(KERN_WARNING "nbd (pid %d: %s) got signal %d\n", 202 task_pid_nr(current), current->comm, 203 dequeue_signal_lock(current, ¤t->blocked, &info)); 204 result = -EINTR; 205 sock_shutdown(nbd, !send); 206 break; 207 } 208 209 if (result <= 0) { 210 if (result == 0) 211 result = -EPIPE; /* short read */ 212 break; 213 } 214 size -= result; 215 buf += result; 216 } while (size > 0); 217 218 sigprocmask(SIG_SETMASK, &oldset, NULL); 219 tsk_restore_flags(current, pflags, PF_MEMALLOC); 220 221 return result; 222 } 223 224 static inline int sock_send_bvec(struct nbd_device *nbd, struct bio_vec *bvec, 225 int flags) 226 { 227 int result; 228 void *kaddr = kmap(bvec->bv_page); 229 result = sock_xmit(nbd, 1, kaddr + bvec->bv_offset, 230 bvec->bv_len, flags); 231 kunmap(bvec->bv_page); 232 return result; 233 } 234 235 /* always call with the tx_lock held */ 236 static int nbd_send_req(struct nbd_device *nbd, struct request *req) 237 { 238 int result, flags; 239 struct nbd_request request; 240 unsigned long size = blk_rq_bytes(req); 241 242 request.magic = htonl(NBD_REQUEST_MAGIC); 243 request.type = htonl(nbd_cmd(req)); 244 request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9); 245 request.len = htonl(size); 246 memcpy(request.handle, &req, sizeof(req)); 247 248 dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%uB)\n", 249 nbd->disk->disk_name, req, 250 nbdcmd_to_ascii(nbd_cmd(req)), 251 (unsigned long long)blk_rq_pos(req) << 9, 252 blk_rq_bytes(req)); 253 result = sock_xmit(nbd, 1, &request, sizeof(request), 254 (nbd_cmd(req) == NBD_CMD_WRITE) ? MSG_MORE : 0); 255 if (result <= 0) { 256 dev_err(disk_to_dev(nbd->disk), 257 "Send control failed (result %d)\n", result); 258 goto error_out; 259 } 260 261 if (nbd_cmd(req) == NBD_CMD_WRITE) { 262 struct req_iterator iter; 263 struct bio_vec *bvec; 264 /* 265 * we are really probing at internals to determine 266 * whether to set MSG_MORE or not... 267 */ 268 rq_for_each_segment(bvec, req, iter) { 269 flags = 0; 270 if (!rq_iter_last(req, iter)) 271 flags = MSG_MORE; 272 dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n", 273 nbd->disk->disk_name, req, bvec->bv_len); 274 result = sock_send_bvec(nbd, bvec, flags); 275 if (result <= 0) { 276 dev_err(disk_to_dev(nbd->disk), 277 "Send data failed (result %d)\n", 278 result); 279 goto error_out; 280 } 281 } 282 } 283 return 0; 284 285 error_out: 286 return -EIO; 287 } 288 289 static struct request *nbd_find_request(struct nbd_device *nbd, 290 struct request *xreq) 291 { 292 struct request *req, *tmp; 293 int err; 294 295 err = wait_event_interruptible(nbd->active_wq, nbd->active_req != xreq); 296 if (unlikely(err)) 297 goto out; 298 299 spin_lock(&nbd->queue_lock); 300 list_for_each_entry_safe(req, tmp, &nbd->queue_head, queuelist) { 301 if (req != xreq) 302 continue; 303 list_del_init(&req->queuelist); 304 spin_unlock(&nbd->queue_lock); 305 return req; 306 } 307 spin_unlock(&nbd->queue_lock); 308 309 err = -ENOENT; 310 311 out: 312 return ERR_PTR(err); 313 } 314 315 static inline int sock_recv_bvec(struct nbd_device *nbd, struct bio_vec *bvec) 316 { 317 int result; 318 void *kaddr = kmap(bvec->bv_page); 319 result = sock_xmit(nbd, 0, kaddr + bvec->bv_offset, bvec->bv_len, 320 MSG_WAITALL); 321 kunmap(bvec->bv_page); 322 return result; 323 } 324 325 /* NULL returned = something went wrong, inform userspace */ 326 static struct request *nbd_read_stat(struct nbd_device *nbd) 327 { 328 int result; 329 struct nbd_reply reply; 330 struct request *req; 331 332 reply.magic = 0; 333 result = sock_xmit(nbd, 0, &reply, sizeof(reply), MSG_WAITALL); 334 if (result <= 0) { 335 dev_err(disk_to_dev(nbd->disk), 336 "Receive control failed (result %d)\n", result); 337 goto harderror; 338 } 339 340 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) { 341 dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n", 342 (unsigned long)ntohl(reply.magic)); 343 result = -EPROTO; 344 goto harderror; 345 } 346 347 req = nbd_find_request(nbd, *(struct request **)reply.handle); 348 if (IS_ERR(req)) { 349 result = PTR_ERR(req); 350 if (result != -ENOENT) 351 goto harderror; 352 353 dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%p)\n", 354 reply.handle); 355 result = -EBADR; 356 goto harderror; 357 } 358 359 if (ntohl(reply.error)) { 360 dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n", 361 ntohl(reply.error)); 362 req->errors++; 363 return req; 364 } 365 366 dprintk(DBG_RX, "%s: request %p: got reply\n", 367 nbd->disk->disk_name, req); 368 if (nbd_cmd(req) == NBD_CMD_READ) { 369 struct req_iterator iter; 370 struct bio_vec *bvec; 371 372 rq_for_each_segment(bvec, req, iter) { 373 result = sock_recv_bvec(nbd, bvec); 374 if (result <= 0) { 375 dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n", 376 result); 377 req->errors++; 378 return req; 379 } 380 dprintk(DBG_RX, "%s: request %p: got %d bytes data\n", 381 nbd->disk->disk_name, req, bvec->bv_len); 382 } 383 } 384 return req; 385 harderror: 386 nbd->harderror = result; 387 return NULL; 388 } 389 390 static ssize_t pid_show(struct device *dev, 391 struct device_attribute *attr, char *buf) 392 { 393 struct gendisk *disk = dev_to_disk(dev); 394 395 return sprintf(buf, "%ld\n", 396 (long) ((struct nbd_device *)disk->private_data)->pid); 397 } 398 399 static struct device_attribute pid_attr = { 400 .attr = { .name = "pid", .mode = S_IRUGO}, 401 .show = pid_show, 402 }; 403 404 static int nbd_do_it(struct nbd_device *nbd) 405 { 406 struct request *req; 407 int ret; 408 409 BUG_ON(nbd->magic != NBD_MAGIC); 410 411 sk_set_memalloc(nbd->sock->sk); 412 nbd->pid = task_pid_nr(current); 413 ret = device_create_file(disk_to_dev(nbd->disk), &pid_attr); 414 if (ret) { 415 dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n"); 416 nbd->pid = 0; 417 return ret; 418 } 419 420 while ((req = nbd_read_stat(nbd)) != NULL) 421 nbd_end_request(req); 422 423 device_remove_file(disk_to_dev(nbd->disk), &pid_attr); 424 nbd->pid = 0; 425 return 0; 426 } 427 428 static void nbd_clear_que(struct nbd_device *nbd) 429 { 430 struct request *req; 431 432 BUG_ON(nbd->magic != NBD_MAGIC); 433 434 /* 435 * Because we have set nbd->sock to NULL under the tx_lock, all 436 * modifications to the list must have completed by now. For 437 * the same reason, the active_req must be NULL. 438 * 439 * As a consequence, we don't need to take the spin lock while 440 * purging the list here. 441 */ 442 BUG_ON(nbd->sock); 443 BUG_ON(nbd->active_req); 444 445 while (!list_empty(&nbd->queue_head)) { 446 req = list_entry(nbd->queue_head.next, struct request, 447 queuelist); 448 list_del_init(&req->queuelist); 449 req->errors++; 450 nbd_end_request(req); 451 } 452 453 while (!list_empty(&nbd->waiting_queue)) { 454 req = list_entry(nbd->waiting_queue.next, struct request, 455 queuelist); 456 list_del_init(&req->queuelist); 457 req->errors++; 458 nbd_end_request(req); 459 } 460 } 461 462 463 static void nbd_handle_req(struct nbd_device *nbd, struct request *req) 464 { 465 if (req->cmd_type != REQ_TYPE_FS) 466 goto error_out; 467 468 nbd_cmd(req) = NBD_CMD_READ; 469 if (rq_data_dir(req) == WRITE) { 470 nbd_cmd(req) = NBD_CMD_WRITE; 471 if (nbd->flags & NBD_READ_ONLY) { 472 dev_err(disk_to_dev(nbd->disk), 473 "Write on read-only\n"); 474 goto error_out; 475 } 476 } 477 478 req->errors = 0; 479 480 mutex_lock(&nbd->tx_lock); 481 if (unlikely(!nbd->sock)) { 482 mutex_unlock(&nbd->tx_lock); 483 dev_err(disk_to_dev(nbd->disk), 484 "Attempted send on closed socket\n"); 485 goto error_out; 486 } 487 488 nbd->active_req = req; 489 490 if (nbd_send_req(nbd, req) != 0) { 491 dev_err(disk_to_dev(nbd->disk), "Request send failed\n"); 492 req->errors++; 493 nbd_end_request(req); 494 } else { 495 spin_lock(&nbd->queue_lock); 496 list_add_tail(&req->queuelist, &nbd->queue_head); 497 spin_unlock(&nbd->queue_lock); 498 } 499 500 nbd->active_req = NULL; 501 mutex_unlock(&nbd->tx_lock); 502 wake_up_all(&nbd->active_wq); 503 504 return; 505 506 error_out: 507 req->errors++; 508 nbd_end_request(req); 509 } 510 511 static int nbd_thread(void *data) 512 { 513 struct nbd_device *nbd = data; 514 struct request *req; 515 516 set_user_nice(current, -20); 517 while (!kthread_should_stop() || !list_empty(&nbd->waiting_queue)) { 518 /* wait for something to do */ 519 wait_event_interruptible(nbd->waiting_wq, 520 kthread_should_stop() || 521 !list_empty(&nbd->waiting_queue)); 522 523 /* extract request */ 524 if (list_empty(&nbd->waiting_queue)) 525 continue; 526 527 spin_lock_irq(&nbd->queue_lock); 528 req = list_entry(nbd->waiting_queue.next, struct request, 529 queuelist); 530 list_del_init(&req->queuelist); 531 spin_unlock_irq(&nbd->queue_lock); 532 533 /* handle request */ 534 nbd_handle_req(nbd, req); 535 } 536 return 0; 537 } 538 539 /* 540 * We always wait for result of write, for now. It would be nice to make it optional 541 * in future 542 * if ((rq_data_dir(req) == WRITE) && (nbd->flags & NBD_WRITE_NOCHK)) 543 * { printk( "Warning: Ignoring result!\n"); nbd_end_request( req ); } 544 */ 545 546 static void do_nbd_request(struct request_queue *q) 547 { 548 struct request *req; 549 550 while ((req = blk_fetch_request(q)) != NULL) { 551 struct nbd_device *nbd; 552 553 spin_unlock_irq(q->queue_lock); 554 555 dprintk(DBG_BLKDEV, "%s: request %p: dequeued (flags=%x)\n", 556 req->rq_disk->disk_name, req, req->cmd_type); 557 558 nbd = req->rq_disk->private_data; 559 560 BUG_ON(nbd->magic != NBD_MAGIC); 561 562 if (unlikely(!nbd->sock)) { 563 dev_err(disk_to_dev(nbd->disk), 564 "Attempted send on closed socket\n"); 565 req->errors++; 566 nbd_end_request(req); 567 spin_lock_irq(q->queue_lock); 568 continue; 569 } 570 571 spin_lock_irq(&nbd->queue_lock); 572 list_add_tail(&req->queuelist, &nbd->waiting_queue); 573 spin_unlock_irq(&nbd->queue_lock); 574 575 wake_up(&nbd->waiting_wq); 576 577 spin_lock_irq(q->queue_lock); 578 } 579 } 580 581 /* Must be called with tx_lock held */ 582 583 static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd, 584 unsigned int cmd, unsigned long arg) 585 { 586 switch (cmd) { 587 case NBD_DISCONNECT: { 588 struct request sreq; 589 590 dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n"); 591 592 blk_rq_init(NULL, &sreq); 593 sreq.cmd_type = REQ_TYPE_SPECIAL; 594 nbd_cmd(&sreq) = NBD_CMD_DISC; 595 if (!nbd->sock) 596 return -EINVAL; 597 nbd_send_req(nbd, &sreq); 598 return 0; 599 } 600 601 case NBD_CLEAR_SOCK: { 602 struct file *file; 603 604 nbd->sock = NULL; 605 file = nbd->file; 606 nbd->file = NULL; 607 nbd_clear_que(nbd); 608 BUG_ON(!list_empty(&nbd->queue_head)); 609 BUG_ON(!list_empty(&nbd->waiting_queue)); 610 if (file) 611 fput(file); 612 return 0; 613 } 614 615 case NBD_SET_SOCK: { 616 struct file *file; 617 if (nbd->file) 618 return -EBUSY; 619 file = fget(arg); 620 if (file) { 621 struct inode *inode = file->f_path.dentry->d_inode; 622 if (S_ISSOCK(inode->i_mode)) { 623 nbd->file = file; 624 nbd->sock = SOCKET_I(inode); 625 if (max_part > 0) 626 bdev->bd_invalidated = 1; 627 return 0; 628 } else { 629 fput(file); 630 } 631 } 632 return -EINVAL; 633 } 634 635 case NBD_SET_BLKSIZE: 636 nbd->blksize = arg; 637 nbd->bytesize &= ~(nbd->blksize-1); 638 bdev->bd_inode->i_size = nbd->bytesize; 639 set_blocksize(bdev, nbd->blksize); 640 set_capacity(nbd->disk, nbd->bytesize >> 9); 641 return 0; 642 643 case NBD_SET_SIZE: 644 nbd->bytesize = arg & ~(nbd->blksize-1); 645 bdev->bd_inode->i_size = nbd->bytesize; 646 set_blocksize(bdev, nbd->blksize); 647 set_capacity(nbd->disk, nbd->bytesize >> 9); 648 return 0; 649 650 case NBD_SET_TIMEOUT: 651 nbd->xmit_timeout = arg * HZ; 652 return 0; 653 654 case NBD_SET_SIZE_BLOCKS: 655 nbd->bytesize = ((u64) arg) * nbd->blksize; 656 bdev->bd_inode->i_size = nbd->bytesize; 657 set_blocksize(bdev, nbd->blksize); 658 set_capacity(nbd->disk, nbd->bytesize >> 9); 659 return 0; 660 661 case NBD_DO_IT: { 662 struct task_struct *thread; 663 struct file *file; 664 int error; 665 666 if (nbd->pid) 667 return -EBUSY; 668 if (!nbd->file) 669 return -EINVAL; 670 671 mutex_unlock(&nbd->tx_lock); 672 673 thread = kthread_create(nbd_thread, nbd, nbd->disk->disk_name); 674 if (IS_ERR(thread)) { 675 mutex_lock(&nbd->tx_lock); 676 return PTR_ERR(thread); 677 } 678 wake_up_process(thread); 679 error = nbd_do_it(nbd); 680 kthread_stop(thread); 681 682 mutex_lock(&nbd->tx_lock); 683 if (error) 684 return error; 685 sock_shutdown(nbd, 0); 686 file = nbd->file; 687 nbd->file = NULL; 688 nbd_clear_que(nbd); 689 dev_warn(disk_to_dev(nbd->disk), "queue cleared\n"); 690 if (file) 691 fput(file); 692 nbd->bytesize = 0; 693 bdev->bd_inode->i_size = 0; 694 set_capacity(nbd->disk, 0); 695 if (max_part > 0) 696 ioctl_by_bdev(bdev, BLKRRPART, 0); 697 return nbd->harderror; 698 } 699 700 case NBD_CLEAR_QUE: 701 /* 702 * This is for compatibility only. The queue is always cleared 703 * by NBD_DO_IT or NBD_CLEAR_SOCK. 704 */ 705 BUG_ON(!nbd->sock && !list_empty(&nbd->queue_head)); 706 return 0; 707 708 case NBD_PRINT_DEBUG: 709 dev_info(disk_to_dev(nbd->disk), 710 "next = %p, prev = %p, head = %p\n", 711 nbd->queue_head.next, nbd->queue_head.prev, 712 &nbd->queue_head); 713 return 0; 714 } 715 return -ENOTTY; 716 } 717 718 static int nbd_ioctl(struct block_device *bdev, fmode_t mode, 719 unsigned int cmd, unsigned long arg) 720 { 721 struct nbd_device *nbd = bdev->bd_disk->private_data; 722 int error; 723 724 if (!capable(CAP_SYS_ADMIN)) 725 return -EPERM; 726 727 BUG_ON(nbd->magic != NBD_MAGIC); 728 729 /* Anyone capable of this syscall can do *real bad* things */ 730 dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n", 731 nbd->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg); 732 733 mutex_lock(&nbd->tx_lock); 734 error = __nbd_ioctl(bdev, nbd, cmd, arg); 735 mutex_unlock(&nbd->tx_lock); 736 737 return error; 738 } 739 740 static const struct block_device_operations nbd_fops = 741 { 742 .owner = THIS_MODULE, 743 .ioctl = nbd_ioctl, 744 }; 745 746 /* 747 * And here should be modules and kernel interface 748 * (Just smiley confuses emacs :-) 749 */ 750 751 static int __init nbd_init(void) 752 { 753 int err = -ENOMEM; 754 int i; 755 int part_shift; 756 757 BUILD_BUG_ON(sizeof(struct nbd_request) != 28); 758 759 if (max_part < 0) { 760 printk(KERN_ERR "nbd: max_part must be >= 0\n"); 761 return -EINVAL; 762 } 763 764 nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL); 765 if (!nbd_dev) 766 return -ENOMEM; 767 768 part_shift = 0; 769 if (max_part > 0) { 770 part_shift = fls(max_part); 771 772 /* 773 * Adjust max_part according to part_shift as it is exported 774 * to user space so that user can know the max number of 775 * partition kernel should be able to manage. 776 * 777 * Note that -1 is required because partition 0 is reserved 778 * for the whole disk. 779 */ 780 max_part = (1UL << part_shift) - 1; 781 } 782 783 if ((1UL << part_shift) > DISK_MAX_PARTS) 784 return -EINVAL; 785 786 if (nbds_max > 1UL << (MINORBITS - part_shift)) 787 return -EINVAL; 788 789 for (i = 0; i < nbds_max; i++) { 790 struct gendisk *disk = alloc_disk(1 << part_shift); 791 if (!disk) 792 goto out; 793 nbd_dev[i].disk = disk; 794 /* 795 * The new linux 2.5 block layer implementation requires 796 * every gendisk to have its very own request_queue struct. 797 * These structs are big so we dynamically allocate them. 798 */ 799 disk->queue = blk_init_queue(do_nbd_request, &nbd_lock); 800 if (!disk->queue) { 801 put_disk(disk); 802 goto out; 803 } 804 /* 805 * Tell the block layer that we are not a rotational device 806 */ 807 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue); 808 } 809 810 if (register_blkdev(NBD_MAJOR, "nbd")) { 811 err = -EIO; 812 goto out; 813 } 814 815 printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR); 816 dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags); 817 818 for (i = 0; i < nbds_max; i++) { 819 struct gendisk *disk = nbd_dev[i].disk; 820 nbd_dev[i].file = NULL; 821 nbd_dev[i].magic = NBD_MAGIC; 822 nbd_dev[i].flags = 0; 823 INIT_LIST_HEAD(&nbd_dev[i].waiting_queue); 824 spin_lock_init(&nbd_dev[i].queue_lock); 825 INIT_LIST_HEAD(&nbd_dev[i].queue_head); 826 mutex_init(&nbd_dev[i].tx_lock); 827 init_waitqueue_head(&nbd_dev[i].active_wq); 828 init_waitqueue_head(&nbd_dev[i].waiting_wq); 829 nbd_dev[i].blksize = 1024; 830 nbd_dev[i].bytesize = 0; 831 disk->major = NBD_MAJOR; 832 disk->first_minor = i << part_shift; 833 disk->fops = &nbd_fops; 834 disk->private_data = &nbd_dev[i]; 835 sprintf(disk->disk_name, "nbd%d", i); 836 set_capacity(disk, 0); 837 add_disk(disk); 838 } 839 840 return 0; 841 out: 842 while (i--) { 843 blk_cleanup_queue(nbd_dev[i].disk->queue); 844 put_disk(nbd_dev[i].disk); 845 } 846 kfree(nbd_dev); 847 return err; 848 } 849 850 static void __exit nbd_cleanup(void) 851 { 852 int i; 853 for (i = 0; i < nbds_max; i++) { 854 struct gendisk *disk = nbd_dev[i].disk; 855 nbd_dev[i].magic = 0; 856 if (disk) { 857 del_gendisk(disk); 858 blk_cleanup_queue(disk->queue); 859 put_disk(disk); 860 } 861 } 862 unregister_blkdev(NBD_MAJOR, "nbd"); 863 kfree(nbd_dev); 864 printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR); 865 } 866 867 module_init(nbd_init); 868 module_exit(nbd_cleanup); 869 870 MODULE_DESCRIPTION("Network Block Device"); 871 MODULE_LICENSE("GPL"); 872 873 module_param(nbds_max, int, 0444); 874 MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)"); 875 module_param(max_part, int, 0444); 876 MODULE_PARM_DESC(max_part, "number of partitions per device (default: 0)"); 877 #ifndef NDEBUG 878 module_param(debugflags, int, 0644); 879 MODULE_PARM_DESC(debugflags, "flags for controlling debug output"); 880 #endif 881