1/* 2 * Network block device - make block devices work over TCP 3 * 4 * Note that you can not swap over this thing, yet. Seems to work but 5 * deadlocks sometimes - you can not swap over TCP in general. 6 * 7 * Copyright 1997-2000, 2008 Pavel Machek <pavel@ucw.cz> 8 * Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com> 9 * 10 * This file is released under GPLv2 or later. 11 * 12 * (part of code stolen from loop.c) 13 */ 14 15#include <linux/major.h> 16 17#include <linux/blkdev.h> 18#include <linux/module.h> 19#include <linux/init.h> 20#include <linux/sched.h> 21#include <linux/fs.h> 22#include <linux/bio.h> 23#include <linux/stat.h> 24#include <linux/errno.h> 25#include <linux/file.h> 26#include <linux/ioctl.h> 27#include <linux/mutex.h> 28#include <linux/compiler.h> 29#include <linux/err.h> 30#include <linux/kernel.h> 31#include <linux/slab.h> 32#include <net/sock.h> 33#include <linux/net.h> 34#include <linux/kthread.h> 35 36#include <asm/uaccess.h> 37#include <asm/types.h> 38 39#include <linux/nbd.h> 40 41#define NBD_MAGIC 0x68797548 42 43#ifdef NDEBUG 44#define dprintk(flags, fmt...) 45#else /* NDEBUG */ 46#define dprintk(flags, fmt...) do { \ 47 if (debugflags & (flags)) printk(KERN_DEBUG fmt); \ 48} while (0) 49#define DBG_IOCTL 0x0004 50#define DBG_INIT 0x0010 51#define DBG_EXIT 0x0020 52#define DBG_BLKDEV 0x0100 53#define DBG_RX 0x0200 54#define DBG_TX 0x0400 55static unsigned int debugflags; 56#endif /* NDEBUG */ 57 58static unsigned int nbds_max = 16; 59static struct nbd_device *nbd_dev; 60static int max_part; 61 62/* 63 * Use just one lock (or at most 1 per NIC). Two arguments for this: 64 * 1. Each NIC is essentially a synchronization point for all servers 65 * accessed through that NIC so there's no need to have more locks 66 * than NICs anyway. 67 * 2. More locks lead to more "Dirty cache line bouncing" which will slow 68 * down each lock to the point where they're actually slower than just 69 * a single lock. 70 * Thanks go to Jens Axboe and Al Viro for their LKML emails explaining this! 71 */ 72static DEFINE_SPINLOCK(nbd_lock); 73 74#ifndef NDEBUG 75static const char *ioctl_cmd_to_ascii(int cmd) 76{ 77 switch (cmd) { 78 case NBD_SET_SOCK: return "set-sock"; 79 case NBD_SET_BLKSIZE: return "set-blksize"; 80 case NBD_SET_SIZE: return "set-size"; 81 case NBD_SET_TIMEOUT: return "set-timeout"; 82 case NBD_SET_FLAGS: return "set-flags"; 83 case NBD_DO_IT: return "do-it"; 84 case NBD_CLEAR_SOCK: return "clear-sock"; 85 case NBD_CLEAR_QUE: return "clear-que"; 86 case NBD_PRINT_DEBUG: return "print-debug"; 87 case NBD_SET_SIZE_BLOCKS: return "set-size-blocks"; 88 case NBD_DISCONNECT: return "disconnect"; 89 case BLKROSET: return "set-read-only"; 90 case BLKFLSBUF: return "flush-buffer-cache"; 91 } 92 return "unknown"; 93} 94 95static const char *nbdcmd_to_ascii(int cmd) 96{ 97 switch (cmd) { 98 case NBD_CMD_READ: return "read"; 99 case NBD_CMD_WRITE: return "write"; 100 case NBD_CMD_DISC: return "disconnect"; 101 case NBD_CMD_FLUSH: return "flush"; 102 case NBD_CMD_TRIM: return "trim/discard"; 103 } 104 return "invalid"; 105} 106#endif /* NDEBUG */ 107 108static void nbd_end_request(struct request *req) 109{ 110 int error = req->errors ? -EIO : 0; 111 struct request_queue *q = req->q; 112 unsigned long flags; 113 114 dprintk(DBG_BLKDEV, "%s: request %p: %s\n", req->rq_disk->disk_name, 115 req, error ? "failed" : "done"); 116 117 spin_lock_irqsave(q->queue_lock, flags); 118 __blk_end_request_all(req, error); 119 spin_unlock_irqrestore(q->queue_lock, flags); 120} 121 122static void sock_shutdown(struct nbd_device *nbd, int lock) 123{ 124 /* Forcibly shutdown the socket causing all listeners 125 * to error 126 * 127 * FIXME: This code is duplicated from sys_shutdown, but 128 * there should be a more generic interface rather than 129 * calling socket ops directly here */ 130 if (lock) 131 mutex_lock(&nbd->tx_lock); 132 if (nbd->sock) { 133 dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n"); 134 kernel_sock_shutdown(nbd->sock, SHUT_RDWR); 135 nbd->sock = NULL; 136 } 137 if (lock) 138 mutex_unlock(&nbd->tx_lock); 139} 140 141static void nbd_xmit_timeout(unsigned long arg) 142{ 143 struct task_struct *task = (struct task_struct *)arg; 144 145 printk(KERN_WARNING "nbd: killing hung xmit (%s, pid: %d)\n", 146 task->comm, task->pid); 147 force_sig(SIGKILL, task); 148} 149 150/* 151 * Send or receive packet. 152 */ 153static int sock_xmit(struct nbd_device *nbd, int send, void *buf, int size, 154 int msg_flags) 155{ 156 struct socket *sock = nbd->sock; 157 int result; 158 struct msghdr msg; 159 struct kvec iov; 160 sigset_t blocked, oldset; 161 unsigned long pflags = current->flags; 162 163 if (unlikely(!sock)) { 164 dev_err(disk_to_dev(nbd->disk), 165 "Attempted %s on closed socket in sock_xmit\n", 166 (send ? "send" : "recv")); 167 return -EINVAL; 168 } 169 170 /* Allow interception of SIGKILL only 171 * Don't allow other signals to interrupt the transmission */ 172 siginitsetinv(&blocked, sigmask(SIGKILL)); 173 sigprocmask(SIG_SETMASK, &blocked, &oldset); 174 175 current->flags |= PF_MEMALLOC; 176 do { 177 sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC; 178 iov.iov_base = buf; 179 iov.iov_len = size; 180 msg.msg_name = NULL; 181 msg.msg_namelen = 0; 182 msg.msg_control = NULL; 183 msg.msg_controllen = 0; 184 msg.msg_flags = msg_flags | MSG_NOSIGNAL; 185 186 if (send) { 187 struct timer_list ti; 188 189 if (nbd->xmit_timeout) { 190 init_timer(&ti); 191 ti.function = nbd_xmit_timeout; 192 ti.data = (unsigned long)current; 193 ti.expires = jiffies + nbd->xmit_timeout; 194 add_timer(&ti); 195 } 196 result = kernel_sendmsg(sock, &msg, &iov, 1, size); 197 if (nbd->xmit_timeout) 198 del_timer_sync(&ti); 199 } else 200 result = kernel_recvmsg(sock, &msg, &iov, 1, size, 201 msg.msg_flags); 202 203 if (signal_pending(current)) { 204 siginfo_t info; 205 printk(KERN_WARNING "nbd (pid %d: %s) got signal %d\n", 206 task_pid_nr(current), current->comm, 207 dequeue_signal_lock(current, ¤t->blocked, &info)); 208 result = -EINTR; 209 sock_shutdown(nbd, !send); 210 break; 211 } 212 213 if (result <= 0) { 214 if (result == 0) 215 result = -EPIPE; /* short read */ 216 break; 217 } 218 size -= result; 219 buf += result; 220 } while (size > 0); 221 222 sigprocmask(SIG_SETMASK, &oldset, NULL); 223 tsk_restore_flags(current, pflags, PF_MEMALLOC); 224 225 return result; 226} 227 228static inline int sock_send_bvec(struct nbd_device *nbd, struct bio_vec *bvec, 229 int flags) 230{ 231 int result; 232 void *kaddr = kmap(bvec->bv_page); 233 result = sock_xmit(nbd, 1, kaddr + bvec->bv_offset, 234 bvec->bv_len, flags); 235 kunmap(bvec->bv_page); 236 return result; 237} 238 239/* always call with the tx_lock held */ 240static int nbd_send_req(struct nbd_device *nbd, struct request *req) 241{ 242 int result, flags; 243 struct nbd_request request; 244 unsigned long size = blk_rq_bytes(req); 245 246 memset(&request, 0, sizeof(request)); 247 request.magic = htonl(NBD_REQUEST_MAGIC); 248 request.type = htonl(nbd_cmd(req)); 249 250 if (nbd_cmd(req) != NBD_CMD_FLUSH && nbd_cmd(req) != NBD_CMD_DISC) { 251 request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9); 252 request.len = htonl(size); 253 } 254 memcpy(request.handle, &req, sizeof(req)); 255 256 dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%uB)\n", 257 nbd->disk->disk_name, req, 258 nbdcmd_to_ascii(nbd_cmd(req)), 259 (unsigned long long)blk_rq_pos(req) << 9, 260 blk_rq_bytes(req)); 261 result = sock_xmit(nbd, 1, &request, sizeof(request), 262 (nbd_cmd(req) == NBD_CMD_WRITE) ? MSG_MORE : 0); 263 if (result <= 0) { 264 dev_err(disk_to_dev(nbd->disk), 265 "Send control failed (result %d)\n", result); 266 goto error_out; 267 } 268 269 if (nbd_cmd(req) == NBD_CMD_WRITE) { 270 struct req_iterator iter; 271 struct bio_vec bvec; 272 /* 273 * we are really probing at internals to determine 274 * whether to set MSG_MORE or not... 275 */ 276 rq_for_each_segment(bvec, req, iter) { 277 flags = 0; 278 if (!rq_iter_last(bvec, iter)) 279 flags = MSG_MORE; 280 dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n", 281 nbd->disk->disk_name, req, bvec.bv_len); 282 result = sock_send_bvec(nbd, &bvec, flags); 283 if (result <= 0) { 284 dev_err(disk_to_dev(nbd->disk), 285 "Send data failed (result %d)\n", 286 result); 287 goto error_out; 288 } 289 } 290 } 291 return 0; 292 293error_out: 294 return -EIO; 295} 296 297static struct request *nbd_find_request(struct nbd_device *nbd, 298 struct request *xreq) 299{ 300 struct request *req, *tmp; 301 int err; 302 303 err = wait_event_interruptible(nbd->active_wq, nbd->active_req != xreq); 304 if (unlikely(err)) 305 goto out; 306 307 spin_lock(&nbd->queue_lock); 308 list_for_each_entry_safe(req, tmp, &nbd->queue_head, queuelist) { 309 if (req != xreq) 310 continue; 311 list_del_init(&req->queuelist); 312 spin_unlock(&nbd->queue_lock); 313 return req; 314 } 315 spin_unlock(&nbd->queue_lock); 316 317 err = -ENOENT; 318 319out: 320 return ERR_PTR(err); 321} 322 323static inline int sock_recv_bvec(struct nbd_device *nbd, struct bio_vec *bvec) 324{ 325 int result; 326 void *kaddr = kmap(bvec->bv_page); 327 result = sock_xmit(nbd, 0, kaddr + bvec->bv_offset, bvec->bv_len, 328 MSG_WAITALL); 329 kunmap(bvec->bv_page); 330 return result; 331} 332 333/* NULL returned = something went wrong, inform userspace */ 334static struct request *nbd_read_stat(struct nbd_device *nbd) 335{ 336 int result; 337 struct nbd_reply reply; 338 struct request *req; 339 340 reply.magic = 0; 341 result = sock_xmit(nbd, 0, &reply, sizeof(reply), MSG_WAITALL); 342 if (result <= 0) { 343 dev_err(disk_to_dev(nbd->disk), 344 "Receive control failed (result %d)\n", result); 345 goto harderror; 346 } 347 348 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) { 349 dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n", 350 (unsigned long)ntohl(reply.magic)); 351 result = -EPROTO; 352 goto harderror; 353 } 354 355 req = nbd_find_request(nbd, *(struct request **)reply.handle); 356 if (IS_ERR(req)) { 357 result = PTR_ERR(req); 358 if (result != -ENOENT) 359 goto harderror; 360 361 dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%p)\n", 362 reply.handle); 363 result = -EBADR; 364 goto harderror; 365 } 366 367 if (ntohl(reply.error)) { 368 dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n", 369 ntohl(reply.error)); 370 req->errors++; 371 return req; 372 } 373 374 dprintk(DBG_RX, "%s: request %p: got reply\n", 375 nbd->disk->disk_name, req); 376 if (nbd_cmd(req) == NBD_CMD_READ) { 377 struct req_iterator iter; 378 struct bio_vec bvec; 379 380 rq_for_each_segment(bvec, req, iter) { 381 result = sock_recv_bvec(nbd, &bvec); 382 if (result <= 0) { 383 dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n", 384 result); 385 req->errors++; 386 return req; 387 } 388 dprintk(DBG_RX, "%s: request %p: got %d bytes data\n", 389 nbd->disk->disk_name, req, bvec.bv_len); 390 } 391 } 392 return req; 393harderror: 394 nbd->harderror = result; 395 return NULL; 396} 397 398static ssize_t pid_show(struct device *dev, 399 struct device_attribute *attr, char *buf) 400{ 401 struct gendisk *disk = dev_to_disk(dev); 402 403 return sprintf(buf, "%ld\n", 404 (long) ((struct nbd_device *)disk->private_data)->pid); 405} 406 407static struct device_attribute pid_attr = { 408 .attr = { .name = "pid", .mode = S_IRUGO}, 409 .show = pid_show, 410}; 411 412static int nbd_do_it(struct nbd_device *nbd) 413{ 414 struct request *req; 415 int ret; 416 417 BUG_ON(nbd->magic != NBD_MAGIC); 418 419 sk_set_memalloc(nbd->sock->sk); 420 nbd->pid = task_pid_nr(current); 421 ret = device_create_file(disk_to_dev(nbd->disk), &pid_attr); 422 if (ret) { 423 dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n"); 424 nbd->pid = 0; 425 return ret; 426 } 427 428 while ((req = nbd_read_stat(nbd)) != NULL) 429 nbd_end_request(req); 430 431 device_remove_file(disk_to_dev(nbd->disk), &pid_attr); 432 nbd->pid = 0; 433 return 0; 434} 435 436static void nbd_clear_que(struct nbd_device *nbd) 437{ 438 struct request *req; 439 440 BUG_ON(nbd->magic != NBD_MAGIC); 441 442 /* 443 * Because we have set nbd->sock to NULL under the tx_lock, all 444 * modifications to the list must have completed by now. For 445 * the same reason, the active_req must be NULL. 446 * 447 * As a consequence, we don't need to take the spin lock while 448 * purging the list here. 449 */ 450 BUG_ON(nbd->sock); 451 BUG_ON(nbd->active_req); 452 453 while (!list_empty(&nbd->queue_head)) { 454 req = list_entry(nbd->queue_head.next, struct request, 455 queuelist); 456 list_del_init(&req->queuelist); 457 req->errors++; 458 nbd_end_request(req); 459 } 460 461 while (!list_empty(&nbd->waiting_queue)) { 462 req = list_entry(nbd->waiting_queue.next, struct request, 463 queuelist); 464 list_del_init(&req->queuelist); 465 req->errors++; 466 nbd_end_request(req); 467 } 468} 469 470 471static void nbd_handle_req(struct nbd_device *nbd, struct request *req) 472{ 473 if (req->cmd_type != REQ_TYPE_FS) 474 goto error_out; 475 476 nbd_cmd(req) = NBD_CMD_READ; 477 if (rq_data_dir(req) == WRITE) { 478 if ((req->cmd_flags & REQ_DISCARD)) { 479 WARN_ON(!(nbd->flags & NBD_FLAG_SEND_TRIM)); 480 nbd_cmd(req) = NBD_CMD_TRIM; 481 } else 482 nbd_cmd(req) = NBD_CMD_WRITE; 483 if (nbd->flags & NBD_FLAG_READ_ONLY) { 484 dev_err(disk_to_dev(nbd->disk), 485 "Write on read-only\n"); 486 goto error_out; 487 } 488 } 489 490 if (req->cmd_flags & REQ_FLUSH) { 491 BUG_ON(unlikely(blk_rq_sectors(req))); 492 nbd_cmd(req) = NBD_CMD_FLUSH; 493 } 494 495 req->errors = 0; 496 497 mutex_lock(&nbd->tx_lock); 498 if (unlikely(!nbd->sock)) { 499 mutex_unlock(&nbd->tx_lock); 500 dev_err(disk_to_dev(nbd->disk), 501 "Attempted send on closed socket\n"); 502 goto error_out; 503 } 504 505 nbd->active_req = req; 506 507 if (nbd_send_req(nbd, req) != 0) { 508 dev_err(disk_to_dev(nbd->disk), "Request send failed\n"); 509 req->errors++; 510 nbd_end_request(req); 511 } else { 512 spin_lock(&nbd->queue_lock); 513 list_add_tail(&req->queuelist, &nbd->queue_head); 514 spin_unlock(&nbd->queue_lock); 515 } 516 517 nbd->active_req = NULL; 518 mutex_unlock(&nbd->tx_lock); 519 wake_up_all(&nbd->active_wq); 520 521 return; 522 523error_out: 524 req->errors++; 525 nbd_end_request(req); 526} 527 528static int nbd_thread(void *data) 529{ 530 struct nbd_device *nbd = data; 531 struct request *req; 532 533 set_user_nice(current, MIN_NICE); 534 while (!kthread_should_stop() || !list_empty(&nbd->waiting_queue)) { 535 /* wait for something to do */ 536 wait_event_interruptible(nbd->waiting_wq, 537 kthread_should_stop() || 538 !list_empty(&nbd->waiting_queue)); 539 540 /* extract request */ 541 if (list_empty(&nbd->waiting_queue)) 542 continue; 543 544 spin_lock_irq(&nbd->queue_lock); 545 req = list_entry(nbd->waiting_queue.next, struct request, 546 queuelist); 547 list_del_init(&req->queuelist); 548 spin_unlock_irq(&nbd->queue_lock); 549 550 /* handle request */ 551 nbd_handle_req(nbd, req); 552 } 553 return 0; 554} 555 556/* 557 * We always wait for result of write, for now. It would be nice to make it optional 558 * in future 559 * if ((rq_data_dir(req) == WRITE) && (nbd->flags & NBD_WRITE_NOCHK)) 560 * { printk( "Warning: Ignoring result!\n"); nbd_end_request( req ); } 561 */ 562 563static void do_nbd_request(struct request_queue *q) 564 __releases(q->queue_lock) __acquires(q->queue_lock) 565{ 566 struct request *req; 567 568 while ((req = blk_fetch_request(q)) != NULL) { 569 struct nbd_device *nbd; 570 571 spin_unlock_irq(q->queue_lock); 572 573 dprintk(DBG_BLKDEV, "%s: request %p: dequeued (flags=%x)\n", 574 req->rq_disk->disk_name, req, req->cmd_type); 575 576 nbd = req->rq_disk->private_data; 577 578 BUG_ON(nbd->magic != NBD_MAGIC); 579 580 if (unlikely(!nbd->sock)) { 581 dev_err(disk_to_dev(nbd->disk), 582 "Attempted send on closed socket\n"); 583 req->errors++; 584 nbd_end_request(req); 585 spin_lock_irq(q->queue_lock); 586 continue; 587 } 588 589 spin_lock_irq(&nbd->queue_lock); 590 list_add_tail(&req->queuelist, &nbd->waiting_queue); 591 spin_unlock_irq(&nbd->queue_lock); 592 593 wake_up(&nbd->waiting_wq); 594 595 spin_lock_irq(q->queue_lock); 596 } 597} 598 599/* Must be called with tx_lock held */ 600 601static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd, 602 unsigned int cmd, unsigned long arg) 603{ 604 switch (cmd) { 605 case NBD_DISCONNECT: { 606 struct request sreq; 607 608 dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n"); 609 if (!nbd->sock) 610 return -EINVAL; 611 612 mutex_unlock(&nbd->tx_lock); 613 fsync_bdev(bdev); 614 mutex_lock(&nbd->tx_lock); 615 blk_rq_init(NULL, &sreq); 616 sreq.cmd_type = REQ_TYPE_SPECIAL; 617 nbd_cmd(&sreq) = NBD_CMD_DISC; 618 619 /* Check again after getting mutex back. */ 620 if (!nbd->sock) 621 return -EINVAL; 622 623 nbd->disconnect = 1; 624 625 nbd_send_req(nbd, &sreq); 626 return 0; 627 } 628 629 case NBD_CLEAR_SOCK: { 630 struct socket *sock = nbd->sock; 631 nbd->sock = NULL; 632 nbd_clear_que(nbd); 633 BUG_ON(!list_empty(&nbd->queue_head)); 634 BUG_ON(!list_empty(&nbd->waiting_queue)); 635 kill_bdev(bdev); 636 if (sock) 637 sockfd_put(sock); 638 return 0; 639 } 640 641 case NBD_SET_SOCK: { 642 struct socket *sock; 643 int err; 644 if (nbd->sock) 645 return -EBUSY; 646 sock = sockfd_lookup(arg, &err); 647 if (sock) { 648 nbd->sock = sock; 649 if (max_part > 0) 650 bdev->bd_invalidated = 1; 651 nbd->disconnect = 0; /* we're connected now */ 652 return 0; 653 } 654 return -EINVAL; 655 } 656 657 case NBD_SET_BLKSIZE: 658 nbd->blksize = arg; 659 nbd->bytesize &= ~(nbd->blksize-1); 660 bdev->bd_inode->i_size = nbd->bytesize; 661 set_blocksize(bdev, nbd->blksize); 662 set_capacity(nbd->disk, nbd->bytesize >> 9); 663 return 0; 664 665 case NBD_SET_SIZE: 666 nbd->bytesize = arg & ~(nbd->blksize-1); 667 bdev->bd_inode->i_size = nbd->bytesize; 668 set_blocksize(bdev, nbd->blksize); 669 set_capacity(nbd->disk, nbd->bytesize >> 9); 670 return 0; 671 672 case NBD_SET_TIMEOUT: 673 nbd->xmit_timeout = arg * HZ; 674 return 0; 675 676 case NBD_SET_FLAGS: 677 nbd->flags = arg; 678 return 0; 679 680 case NBD_SET_SIZE_BLOCKS: 681 nbd->bytesize = ((u64) arg) * nbd->blksize; 682 bdev->bd_inode->i_size = nbd->bytesize; 683 set_blocksize(bdev, nbd->blksize); 684 set_capacity(nbd->disk, nbd->bytesize >> 9); 685 return 0; 686 687 case NBD_DO_IT: { 688 struct task_struct *thread; 689 struct socket *sock; 690 int error; 691 692 if (nbd->pid) 693 return -EBUSY; 694 if (!nbd->sock) 695 return -EINVAL; 696 697 mutex_unlock(&nbd->tx_lock); 698 699 if (nbd->flags & NBD_FLAG_READ_ONLY) 700 set_device_ro(bdev, true); 701 if (nbd->flags & NBD_FLAG_SEND_TRIM) 702 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, 703 nbd->disk->queue); 704 if (nbd->flags & NBD_FLAG_SEND_FLUSH) 705 blk_queue_flush(nbd->disk->queue, REQ_FLUSH); 706 else 707 blk_queue_flush(nbd->disk->queue, 0); 708 709 thread = kthread_create(nbd_thread, nbd, "%s", 710 nbd->disk->disk_name); 711 if (IS_ERR(thread)) { 712 mutex_lock(&nbd->tx_lock); 713 return PTR_ERR(thread); 714 } 715 wake_up_process(thread); 716 error = nbd_do_it(nbd); 717 kthread_stop(thread); 718 719 mutex_lock(&nbd->tx_lock); 720 if (error) 721 return error; 722 sock_shutdown(nbd, 0); 723 sock = nbd->sock; 724 nbd->sock = NULL; 725 nbd_clear_que(nbd); 726 dev_warn(disk_to_dev(nbd->disk), "queue cleared\n"); 727 kill_bdev(bdev); 728 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue); 729 set_device_ro(bdev, false); 730 if (sock) 731 sockfd_put(sock); 732 nbd->flags = 0; 733 nbd->bytesize = 0; 734 bdev->bd_inode->i_size = 0; 735 set_capacity(nbd->disk, 0); 736 if (max_part > 0) 737 ioctl_by_bdev(bdev, BLKRRPART, 0); 738 if (nbd->disconnect) /* user requested, ignore socket errors */ 739 return 0; 740 return nbd->harderror; 741 } 742 743 case NBD_CLEAR_QUE: 744 /* 745 * This is for compatibility only. The queue is always cleared 746 * by NBD_DO_IT or NBD_CLEAR_SOCK. 747 */ 748 return 0; 749 750 case NBD_PRINT_DEBUG: 751 dev_info(disk_to_dev(nbd->disk), 752 "next = %p, prev = %p, head = %p\n", 753 nbd->queue_head.next, nbd->queue_head.prev, 754 &nbd->queue_head); 755 return 0; 756 } 757 return -ENOTTY; 758} 759 760static int nbd_ioctl(struct block_device *bdev, fmode_t mode, 761 unsigned int cmd, unsigned long arg) 762{ 763 struct nbd_device *nbd = bdev->bd_disk->private_data; 764 int error; 765 766 if (!capable(CAP_SYS_ADMIN)) 767 return -EPERM; 768 769 BUG_ON(nbd->magic != NBD_MAGIC); 770 771 /* Anyone capable of this syscall can do *real bad* things */ 772 dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n", 773 nbd->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg); 774 775 mutex_lock(&nbd->tx_lock); 776 error = __nbd_ioctl(bdev, nbd, cmd, arg); 777 mutex_unlock(&nbd->tx_lock); 778 779 return error; 780} 781 782static const struct block_device_operations nbd_fops = 783{ 784 .owner = THIS_MODULE, 785 .ioctl = nbd_ioctl, 786}; 787 788/* 789 * And here should be modules and kernel interface 790 * (Just smiley confuses emacs :-) 791 */ 792 793static int __init nbd_init(void) 794{ 795 int err = -ENOMEM; 796 int i; 797 int part_shift; 798 799 BUILD_BUG_ON(sizeof(struct nbd_request) != 28); 800 801 if (max_part < 0) { 802 printk(KERN_ERR "nbd: max_part must be >= 0\n"); 803 return -EINVAL; 804 } 805 806 nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL); 807 if (!nbd_dev) 808 return -ENOMEM; 809 810 part_shift = 0; 811 if (max_part > 0) { 812 part_shift = fls(max_part); 813 814 /* 815 * Adjust max_part according to part_shift as it is exported 816 * to user space so that user can know the max number of 817 * partition kernel should be able to manage. 818 * 819 * Note that -1 is required because partition 0 is reserved 820 * for the whole disk. 821 */ 822 max_part = (1UL << part_shift) - 1; 823 } 824 825 if ((1UL << part_shift) > DISK_MAX_PARTS) 826 return -EINVAL; 827 828 if (nbds_max > 1UL << (MINORBITS - part_shift)) 829 return -EINVAL; 830 831 for (i = 0; i < nbds_max; i++) { 832 struct gendisk *disk = alloc_disk(1 << part_shift); 833 if (!disk) 834 goto out; 835 nbd_dev[i].disk = disk; 836 /* 837 * The new linux 2.5 block layer implementation requires 838 * every gendisk to have its very own request_queue struct. 839 * These structs are big so we dynamically allocate them. 840 */ 841 disk->queue = blk_init_queue(do_nbd_request, &nbd_lock); 842 if (!disk->queue) { 843 put_disk(disk); 844 goto out; 845 } 846 /* 847 * Tell the block layer that we are not a rotational device 848 */ 849 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue); 850 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, disk->queue); 851 disk->queue->limits.discard_granularity = 512; 852 disk->queue->limits.max_discard_sectors = UINT_MAX; 853 disk->queue->limits.discard_zeroes_data = 0; 854 blk_queue_max_hw_sectors(disk->queue, 65536); 855 disk->queue->limits.max_sectors = 256; 856 } 857 858 if (register_blkdev(NBD_MAJOR, "nbd")) { 859 err = -EIO; 860 goto out; 861 } 862 863 printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR); 864 dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags); 865 866 for (i = 0; i < nbds_max; i++) { 867 struct gendisk *disk = nbd_dev[i].disk; 868 nbd_dev[i].magic = NBD_MAGIC; 869 INIT_LIST_HEAD(&nbd_dev[i].waiting_queue); 870 spin_lock_init(&nbd_dev[i].queue_lock); 871 INIT_LIST_HEAD(&nbd_dev[i].queue_head); 872 mutex_init(&nbd_dev[i].tx_lock); 873 init_waitqueue_head(&nbd_dev[i].active_wq); 874 init_waitqueue_head(&nbd_dev[i].waiting_wq); 875 nbd_dev[i].blksize = 1024; 876 nbd_dev[i].bytesize = 0; 877 disk->major = NBD_MAJOR; 878 disk->first_minor = i << part_shift; 879 disk->fops = &nbd_fops; 880 disk->private_data = &nbd_dev[i]; 881 sprintf(disk->disk_name, "nbd%d", i); 882 set_capacity(disk, 0); 883 add_disk(disk); 884 } 885 886 return 0; 887out: 888 while (i--) { 889 blk_cleanup_queue(nbd_dev[i].disk->queue); 890 put_disk(nbd_dev[i].disk); 891 } 892 kfree(nbd_dev); 893 return err; 894} 895 896static void __exit nbd_cleanup(void) 897{ 898 int i; 899 for (i = 0; i < nbds_max; i++) { 900 struct gendisk *disk = nbd_dev[i].disk; 901 nbd_dev[i].magic = 0; 902 if (disk) { 903 del_gendisk(disk); 904 blk_cleanup_queue(disk->queue); 905 put_disk(disk); 906 } 907 } 908 unregister_blkdev(NBD_MAJOR, "nbd"); 909 kfree(nbd_dev); 910 printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR); 911} 912 913module_init(nbd_init); 914module_exit(nbd_cleanup); 915 916MODULE_DESCRIPTION("Network Block Device"); 917MODULE_LICENSE("GPL"); 918 919module_param(nbds_max, int, 0444); 920MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)"); 921module_param(max_part, int, 0444); 922MODULE_PARM_DESC(max_part, "number of partitions per device (default: 0)"); 923#ifndef NDEBUG 924module_param(debugflags, int, 0644); 925MODULE_PARM_DESC(debugflags, "flags for controlling debug output"); 926#endif 927