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 #include <linux/types.h> 36 #include <linux/debugfs.h> 37 38 #include <asm/uaccess.h> 39 #include <asm/types.h> 40 41 #include <linux/nbd.h> 42 43 struct nbd_device { 44 u32 flags; 45 struct socket * sock; /* If == NULL, device is not ready, yet */ 46 int magic; 47 48 spinlock_t queue_lock; 49 struct list_head queue_head; /* Requests waiting result */ 50 struct request *active_req; 51 wait_queue_head_t active_wq; 52 struct list_head waiting_queue; /* Requests to be sent */ 53 wait_queue_head_t waiting_wq; 54 55 struct mutex tx_lock; 56 struct gendisk *disk; 57 int blksize; 58 loff_t bytesize; 59 int xmit_timeout; 60 bool disconnect; /* a disconnect has been requested by user */ 61 62 struct timer_list timeout_timer; 63 spinlock_t tasks_lock; 64 struct task_struct *task_recv; 65 struct task_struct *task_send; 66 67 #if IS_ENABLED(CONFIG_DEBUG_FS) 68 struct dentry *dbg_dir; 69 #endif 70 }; 71 72 #if IS_ENABLED(CONFIG_DEBUG_FS) 73 static struct dentry *nbd_dbg_dir; 74 #endif 75 76 #define nbd_name(nbd) ((nbd)->disk->disk_name) 77 78 #define NBD_MAGIC 0x68797548 79 80 static unsigned int nbds_max = 16; 81 static struct nbd_device *nbd_dev; 82 static int max_part; 83 84 /* 85 * Use just one lock (or at most 1 per NIC). Two arguments for this: 86 * 1. Each NIC is essentially a synchronization point for all servers 87 * accessed through that NIC so there's no need to have more locks 88 * than NICs anyway. 89 * 2. More locks lead to more "Dirty cache line bouncing" which will slow 90 * down each lock to the point where they're actually slower than just 91 * a single lock. 92 * Thanks go to Jens Axboe and Al Viro for their LKML emails explaining this! 93 */ 94 static DEFINE_SPINLOCK(nbd_lock); 95 96 static inline struct device *nbd_to_dev(struct nbd_device *nbd) 97 { 98 return disk_to_dev(nbd->disk); 99 } 100 101 static const char *nbdcmd_to_ascii(int cmd) 102 { 103 switch (cmd) { 104 case NBD_CMD_READ: return "read"; 105 case NBD_CMD_WRITE: return "write"; 106 case NBD_CMD_DISC: return "disconnect"; 107 case NBD_CMD_FLUSH: return "flush"; 108 case NBD_CMD_TRIM: return "trim/discard"; 109 } 110 return "invalid"; 111 } 112 113 static void nbd_end_request(struct nbd_device *nbd, struct request *req) 114 { 115 int error = req->errors ? -EIO : 0; 116 struct request_queue *q = req->q; 117 unsigned long flags; 118 119 dev_dbg(nbd_to_dev(nbd), "request %p: %s\n", req, 120 error ? "failed" : "done"); 121 122 spin_lock_irqsave(q->queue_lock, flags); 123 __blk_end_request_all(req, error); 124 spin_unlock_irqrestore(q->queue_lock, flags); 125 } 126 127 /* 128 * Forcibly shutdown the socket causing all listeners to error 129 */ 130 static void sock_shutdown(struct nbd_device *nbd) 131 { 132 if (!nbd->sock) 133 return; 134 135 dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n"); 136 kernel_sock_shutdown(nbd->sock, SHUT_RDWR); 137 nbd->sock = NULL; 138 del_timer_sync(&nbd->timeout_timer); 139 } 140 141 static void nbd_xmit_timeout(unsigned long arg) 142 { 143 struct nbd_device *nbd = (struct nbd_device *)arg; 144 unsigned long flags; 145 146 if (list_empty(&nbd->queue_head)) 147 return; 148 149 nbd->disconnect = true; 150 151 spin_lock_irqsave(&nbd->tasks_lock, flags); 152 153 if (nbd->task_recv) 154 force_sig(SIGKILL, nbd->task_recv); 155 156 if (nbd->task_send) 157 force_sig(SIGKILL, nbd->task_send); 158 159 spin_unlock_irqrestore(&nbd->tasks_lock, flags); 160 161 dev_err(nbd_to_dev(nbd), "Connection timed out, killed receiver and sender, shutting down connection\n"); 162 } 163 164 /* 165 * Send or receive packet. 166 */ 167 static int sock_xmit(struct nbd_device *nbd, int send, void *buf, int size, 168 int msg_flags) 169 { 170 struct socket *sock = nbd->sock; 171 int result; 172 struct msghdr msg; 173 struct kvec iov; 174 sigset_t blocked, oldset; 175 unsigned long pflags = current->flags; 176 177 if (unlikely(!sock)) { 178 dev_err(disk_to_dev(nbd->disk), 179 "Attempted %s on closed socket in sock_xmit\n", 180 (send ? "send" : "recv")); 181 return -EINVAL; 182 } 183 184 /* Allow interception of SIGKILL only 185 * Don't allow other signals to interrupt the transmission */ 186 siginitsetinv(&blocked, sigmask(SIGKILL)); 187 sigprocmask(SIG_SETMASK, &blocked, &oldset); 188 189 current->flags |= PF_MEMALLOC; 190 do { 191 sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC; 192 iov.iov_base = buf; 193 iov.iov_len = size; 194 msg.msg_name = NULL; 195 msg.msg_namelen = 0; 196 msg.msg_control = NULL; 197 msg.msg_controllen = 0; 198 msg.msg_flags = msg_flags | MSG_NOSIGNAL; 199 200 if (send) 201 result = kernel_sendmsg(sock, &msg, &iov, 1, size); 202 else 203 result = kernel_recvmsg(sock, &msg, &iov, 1, size, 204 msg.msg_flags); 205 206 if (result <= 0) { 207 if (result == 0) 208 result = -EPIPE; /* short read */ 209 break; 210 } 211 size -= result; 212 buf += result; 213 } while (size > 0); 214 215 sigprocmask(SIG_SETMASK, &oldset, NULL); 216 tsk_restore_flags(current, pflags, PF_MEMALLOC); 217 218 if (!send && nbd->xmit_timeout) 219 mod_timer(&nbd->timeout_timer, jiffies + nbd->xmit_timeout); 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 u32 type; 242 243 if (req->cmd_type == REQ_TYPE_DRV_PRIV) 244 type = NBD_CMD_DISC; 245 else if (req->cmd_flags & REQ_DISCARD) 246 type = NBD_CMD_TRIM; 247 else if (req->cmd_flags & REQ_FLUSH) 248 type = NBD_CMD_FLUSH; 249 else if (rq_data_dir(req) == WRITE) 250 type = NBD_CMD_WRITE; 251 else 252 type = NBD_CMD_READ; 253 254 memset(&request, 0, sizeof(request)); 255 request.magic = htonl(NBD_REQUEST_MAGIC); 256 request.type = htonl(type); 257 if (type != NBD_CMD_FLUSH && type != NBD_CMD_DISC) { 258 request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9); 259 request.len = htonl(size); 260 } 261 memcpy(request.handle, &req, sizeof(req)); 262 263 dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n", 264 req, nbdcmd_to_ascii(type), 265 (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req)); 266 result = sock_xmit(nbd, 1, &request, sizeof(request), 267 (type == NBD_CMD_WRITE) ? MSG_MORE : 0); 268 if (result <= 0) { 269 dev_err(disk_to_dev(nbd->disk), 270 "Send control failed (result %d)\n", result); 271 return -EIO; 272 } 273 274 if (type == NBD_CMD_WRITE) { 275 struct req_iterator iter; 276 struct bio_vec bvec; 277 /* 278 * we are really probing at internals to determine 279 * whether to set MSG_MORE or not... 280 */ 281 rq_for_each_segment(bvec, req, iter) { 282 flags = 0; 283 if (!rq_iter_last(bvec, iter)) 284 flags = MSG_MORE; 285 dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n", 286 req, bvec.bv_len); 287 result = sock_send_bvec(nbd, &bvec, flags); 288 if (result <= 0) { 289 dev_err(disk_to_dev(nbd->disk), 290 "Send data failed (result %d)\n", 291 result); 292 return -EIO; 293 } 294 } 295 } 296 return 0; 297 } 298 299 static struct request *nbd_find_request(struct nbd_device *nbd, 300 struct request *xreq) 301 { 302 struct request *req, *tmp; 303 int err; 304 305 err = wait_event_interruptible(nbd->active_wq, nbd->active_req != xreq); 306 if (unlikely(err)) 307 return ERR_PTR(err); 308 309 spin_lock(&nbd->queue_lock); 310 list_for_each_entry_safe(req, tmp, &nbd->queue_head, queuelist) { 311 if (req != xreq) 312 continue; 313 list_del_init(&req->queuelist); 314 spin_unlock(&nbd->queue_lock); 315 return req; 316 } 317 spin_unlock(&nbd->queue_lock); 318 319 return ERR_PTR(-ENOENT); 320 } 321 322 static inline int sock_recv_bvec(struct nbd_device *nbd, struct bio_vec *bvec) 323 { 324 int result; 325 void *kaddr = kmap(bvec->bv_page); 326 result = sock_xmit(nbd, 0, kaddr + bvec->bv_offset, bvec->bv_len, 327 MSG_WAITALL); 328 kunmap(bvec->bv_page); 329 return result; 330 } 331 332 /* NULL returned = something went wrong, inform userspace */ 333 static struct request *nbd_read_stat(struct nbd_device *nbd) 334 { 335 int result; 336 struct nbd_reply reply; 337 struct request *req; 338 339 reply.magic = 0; 340 result = sock_xmit(nbd, 0, &reply, sizeof(reply), MSG_WAITALL); 341 if (result <= 0) { 342 dev_err(disk_to_dev(nbd->disk), 343 "Receive control failed (result %d)\n", result); 344 return ERR_PTR(result); 345 } 346 347 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) { 348 dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n", 349 (unsigned long)ntohl(reply.magic)); 350 return ERR_PTR(-EPROTO); 351 } 352 353 req = nbd_find_request(nbd, *(struct request **)reply.handle); 354 if (IS_ERR(req)) { 355 result = PTR_ERR(req); 356 if (result != -ENOENT) 357 return ERR_PTR(result); 358 359 dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%p)\n", 360 reply.handle); 361 return ERR_PTR(-EBADR); 362 } 363 364 if (ntohl(reply.error)) { 365 dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n", 366 ntohl(reply.error)); 367 req->errors++; 368 return req; 369 } 370 371 dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", req); 372 if (rq_data_dir(req) != WRITE) { 373 struct req_iterator iter; 374 struct bio_vec bvec; 375 376 rq_for_each_segment(bvec, req, iter) { 377 result = sock_recv_bvec(nbd, &bvec); 378 if (result <= 0) { 379 dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n", 380 result); 381 req->errors++; 382 return req; 383 } 384 dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n", 385 req, bvec.bv_len); 386 } 387 } 388 return req; 389 } 390 391 static ssize_t pid_show(struct device *dev, 392 struct device_attribute *attr, char *buf) 393 { 394 struct gendisk *disk = dev_to_disk(dev); 395 struct nbd_device *nbd = (struct nbd_device *)disk->private_data; 396 397 return sprintf(buf, "%d\n", task_pid_nr(nbd->task_recv)); 398 } 399 400 static struct device_attribute pid_attr = { 401 .attr = { .name = "pid", .mode = S_IRUGO}, 402 .show = pid_show, 403 }; 404 405 static int nbd_thread_recv(struct nbd_device *nbd) 406 { 407 struct request *req; 408 int ret; 409 unsigned long flags; 410 411 BUG_ON(nbd->magic != NBD_MAGIC); 412 413 sk_set_memalloc(nbd->sock->sk); 414 415 spin_lock_irqsave(&nbd->tasks_lock, flags); 416 nbd->task_recv = current; 417 spin_unlock_irqrestore(&nbd->tasks_lock, flags); 418 419 ret = device_create_file(disk_to_dev(nbd->disk), &pid_attr); 420 if (ret) { 421 dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n"); 422 423 spin_lock_irqsave(&nbd->tasks_lock, flags); 424 nbd->task_recv = NULL; 425 spin_unlock_irqrestore(&nbd->tasks_lock, flags); 426 427 return ret; 428 } 429 430 while (1) { 431 req = nbd_read_stat(nbd); 432 if (IS_ERR(req)) { 433 ret = PTR_ERR(req); 434 break; 435 } 436 437 nbd_end_request(nbd, req); 438 } 439 440 device_remove_file(disk_to_dev(nbd->disk), &pid_attr); 441 442 spin_lock_irqsave(&nbd->tasks_lock, flags); 443 nbd->task_recv = NULL; 444 spin_unlock_irqrestore(&nbd->tasks_lock, flags); 445 446 if (signal_pending(current)) { 447 ret = kernel_dequeue_signal(NULL); 448 dev_warn(nbd_to_dev(nbd), "pid %d, %s, got signal %d\n", 449 task_pid_nr(current), current->comm, ret); 450 mutex_lock(&nbd->tx_lock); 451 sock_shutdown(nbd); 452 mutex_unlock(&nbd->tx_lock); 453 ret = -ETIMEDOUT; 454 } 455 456 return ret; 457 } 458 459 static void nbd_clear_que(struct nbd_device *nbd) 460 { 461 struct request *req; 462 463 BUG_ON(nbd->magic != NBD_MAGIC); 464 465 /* 466 * Because we have set nbd->sock to NULL under the tx_lock, all 467 * modifications to the list must have completed by now. For 468 * the same reason, the active_req must be NULL. 469 * 470 * As a consequence, we don't need to take the spin lock while 471 * purging the list here. 472 */ 473 BUG_ON(nbd->sock); 474 BUG_ON(nbd->active_req); 475 476 while (!list_empty(&nbd->queue_head)) { 477 req = list_entry(nbd->queue_head.next, struct request, 478 queuelist); 479 list_del_init(&req->queuelist); 480 req->errors++; 481 nbd_end_request(nbd, req); 482 } 483 484 while (!list_empty(&nbd->waiting_queue)) { 485 req = list_entry(nbd->waiting_queue.next, struct request, 486 queuelist); 487 list_del_init(&req->queuelist); 488 req->errors++; 489 nbd_end_request(nbd, req); 490 } 491 dev_dbg(disk_to_dev(nbd->disk), "queue cleared\n"); 492 } 493 494 495 static void nbd_handle_req(struct nbd_device *nbd, struct request *req) 496 { 497 if (req->cmd_type != REQ_TYPE_FS) 498 goto error_out; 499 500 if (rq_data_dir(req) == WRITE && 501 (nbd->flags & NBD_FLAG_READ_ONLY)) { 502 dev_err(disk_to_dev(nbd->disk), 503 "Write on read-only\n"); 504 goto error_out; 505 } 506 507 req->errors = 0; 508 509 mutex_lock(&nbd->tx_lock); 510 if (unlikely(!nbd->sock)) { 511 mutex_unlock(&nbd->tx_lock); 512 dev_err(disk_to_dev(nbd->disk), 513 "Attempted send on closed socket\n"); 514 goto error_out; 515 } 516 517 nbd->active_req = req; 518 519 if (nbd->xmit_timeout && list_empty_careful(&nbd->queue_head)) 520 mod_timer(&nbd->timeout_timer, jiffies + nbd->xmit_timeout); 521 522 if (nbd_send_req(nbd, req) != 0) { 523 dev_err(disk_to_dev(nbd->disk), "Request send failed\n"); 524 req->errors++; 525 nbd_end_request(nbd, req); 526 } else { 527 spin_lock(&nbd->queue_lock); 528 list_add_tail(&req->queuelist, &nbd->queue_head); 529 spin_unlock(&nbd->queue_lock); 530 } 531 532 nbd->active_req = NULL; 533 mutex_unlock(&nbd->tx_lock); 534 wake_up_all(&nbd->active_wq); 535 536 return; 537 538 error_out: 539 req->errors++; 540 nbd_end_request(nbd, req); 541 } 542 543 static int nbd_thread_send(void *data) 544 { 545 struct nbd_device *nbd = data; 546 struct request *req; 547 unsigned long flags; 548 549 spin_lock_irqsave(&nbd->tasks_lock, flags); 550 nbd->task_send = current; 551 spin_unlock_irqrestore(&nbd->tasks_lock, flags); 552 553 set_user_nice(current, MIN_NICE); 554 while (!kthread_should_stop() || !list_empty(&nbd->waiting_queue)) { 555 /* wait for something to do */ 556 wait_event_interruptible(nbd->waiting_wq, 557 kthread_should_stop() || 558 !list_empty(&nbd->waiting_queue)); 559 560 if (signal_pending(current)) { 561 int ret = kernel_dequeue_signal(NULL); 562 563 dev_warn(nbd_to_dev(nbd), "pid %d, %s, got signal %d\n", 564 task_pid_nr(current), current->comm, ret); 565 mutex_lock(&nbd->tx_lock); 566 sock_shutdown(nbd); 567 mutex_unlock(&nbd->tx_lock); 568 break; 569 } 570 571 /* extract request */ 572 if (list_empty(&nbd->waiting_queue)) 573 continue; 574 575 spin_lock_irq(&nbd->queue_lock); 576 req = list_entry(nbd->waiting_queue.next, struct request, 577 queuelist); 578 list_del_init(&req->queuelist); 579 spin_unlock_irq(&nbd->queue_lock); 580 581 /* handle request */ 582 nbd_handle_req(nbd, req); 583 } 584 585 spin_lock_irqsave(&nbd->tasks_lock, flags); 586 nbd->task_send = NULL; 587 spin_unlock_irqrestore(&nbd->tasks_lock, flags); 588 589 /* Clear maybe pending signals */ 590 if (signal_pending(current)) 591 kernel_dequeue_signal(NULL); 592 593 return 0; 594 } 595 596 /* 597 * We always wait for result of write, for now. It would be nice to make it optional 598 * in future 599 * if ((rq_data_dir(req) == WRITE) && (nbd->flags & NBD_WRITE_NOCHK)) 600 * { printk( "Warning: Ignoring result!\n"); nbd_end_request( req ); } 601 */ 602 603 static void nbd_request_handler(struct request_queue *q) 604 __releases(q->queue_lock) __acquires(q->queue_lock) 605 { 606 struct request *req; 607 608 while ((req = blk_fetch_request(q)) != NULL) { 609 struct nbd_device *nbd; 610 611 spin_unlock_irq(q->queue_lock); 612 613 nbd = req->rq_disk->private_data; 614 615 BUG_ON(nbd->magic != NBD_MAGIC); 616 617 dev_dbg(nbd_to_dev(nbd), "request %p: dequeued (flags=%x)\n", 618 req, req->cmd_type); 619 620 if (unlikely(!nbd->sock)) { 621 dev_err(disk_to_dev(nbd->disk), 622 "Attempted send on closed socket\n"); 623 req->errors++; 624 nbd_end_request(nbd, req); 625 spin_lock_irq(q->queue_lock); 626 continue; 627 } 628 629 spin_lock_irq(&nbd->queue_lock); 630 list_add_tail(&req->queuelist, &nbd->waiting_queue); 631 spin_unlock_irq(&nbd->queue_lock); 632 633 wake_up(&nbd->waiting_wq); 634 635 spin_lock_irq(q->queue_lock); 636 } 637 } 638 639 static int nbd_dev_dbg_init(struct nbd_device *nbd); 640 static void nbd_dev_dbg_close(struct nbd_device *nbd); 641 642 /* Must be called with tx_lock held */ 643 644 static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd, 645 unsigned int cmd, unsigned long arg) 646 { 647 switch (cmd) { 648 case NBD_DISCONNECT: { 649 struct request sreq; 650 651 dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n"); 652 if (!nbd->sock) 653 return -EINVAL; 654 655 mutex_unlock(&nbd->tx_lock); 656 fsync_bdev(bdev); 657 mutex_lock(&nbd->tx_lock); 658 blk_rq_init(NULL, &sreq); 659 sreq.cmd_type = REQ_TYPE_DRV_PRIV; 660 661 /* Check again after getting mutex back. */ 662 if (!nbd->sock) 663 return -EINVAL; 664 665 nbd->disconnect = true; 666 667 nbd_send_req(nbd, &sreq); 668 return 0; 669 } 670 671 case NBD_CLEAR_SOCK: { 672 struct socket *sock = nbd->sock; 673 nbd->sock = NULL; 674 nbd_clear_que(nbd); 675 BUG_ON(!list_empty(&nbd->queue_head)); 676 BUG_ON(!list_empty(&nbd->waiting_queue)); 677 kill_bdev(bdev); 678 if (sock) 679 sockfd_put(sock); 680 return 0; 681 } 682 683 case NBD_SET_SOCK: { 684 struct socket *sock; 685 int err; 686 if (nbd->sock) 687 return -EBUSY; 688 sock = sockfd_lookup(arg, &err); 689 if (sock) { 690 nbd->sock = sock; 691 if (max_part > 0) 692 bdev->bd_invalidated = 1; 693 nbd->disconnect = false; /* we're connected now */ 694 return 0; 695 } 696 return -EINVAL; 697 } 698 699 case NBD_SET_BLKSIZE: 700 nbd->blksize = arg; 701 nbd->bytesize &= ~(nbd->blksize-1); 702 bdev->bd_inode->i_size = nbd->bytesize; 703 set_blocksize(bdev, nbd->blksize); 704 set_capacity(nbd->disk, nbd->bytesize >> 9); 705 return 0; 706 707 case NBD_SET_SIZE: 708 nbd->bytesize = arg & ~(nbd->blksize-1); 709 bdev->bd_inode->i_size = nbd->bytesize; 710 set_blocksize(bdev, nbd->blksize); 711 set_capacity(nbd->disk, nbd->bytesize >> 9); 712 return 0; 713 714 case NBD_SET_TIMEOUT: 715 nbd->xmit_timeout = arg * HZ; 716 if (arg) 717 mod_timer(&nbd->timeout_timer, 718 jiffies + nbd->xmit_timeout); 719 else 720 del_timer_sync(&nbd->timeout_timer); 721 722 return 0; 723 724 case NBD_SET_FLAGS: 725 nbd->flags = arg; 726 return 0; 727 728 case NBD_SET_SIZE_BLOCKS: 729 nbd->bytesize = ((u64) arg) * nbd->blksize; 730 bdev->bd_inode->i_size = nbd->bytesize; 731 set_blocksize(bdev, nbd->blksize); 732 set_capacity(nbd->disk, nbd->bytesize >> 9); 733 return 0; 734 735 case NBD_DO_IT: { 736 struct task_struct *thread; 737 struct socket *sock; 738 int error; 739 740 if (nbd->task_recv) 741 return -EBUSY; 742 if (!nbd->sock) 743 return -EINVAL; 744 745 mutex_unlock(&nbd->tx_lock); 746 747 if (nbd->flags & NBD_FLAG_READ_ONLY) 748 set_device_ro(bdev, true); 749 if (nbd->flags & NBD_FLAG_SEND_TRIM) 750 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, 751 nbd->disk->queue); 752 if (nbd->flags & NBD_FLAG_SEND_FLUSH) 753 blk_queue_flush(nbd->disk->queue, REQ_FLUSH); 754 else 755 blk_queue_flush(nbd->disk->queue, 0); 756 757 thread = kthread_run(nbd_thread_send, nbd, "%s", 758 nbd_name(nbd)); 759 if (IS_ERR(thread)) { 760 mutex_lock(&nbd->tx_lock); 761 return PTR_ERR(thread); 762 } 763 764 nbd_dev_dbg_init(nbd); 765 error = nbd_thread_recv(nbd); 766 nbd_dev_dbg_close(nbd); 767 kthread_stop(thread); 768 769 mutex_lock(&nbd->tx_lock); 770 771 sock_shutdown(nbd); 772 sock = nbd->sock; 773 nbd->sock = NULL; 774 nbd_clear_que(nbd); 775 kill_bdev(bdev); 776 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue); 777 set_device_ro(bdev, false); 778 if (sock) 779 sockfd_put(sock); 780 nbd->flags = 0; 781 nbd->bytesize = 0; 782 bdev->bd_inode->i_size = 0; 783 set_capacity(nbd->disk, 0); 784 if (max_part > 0) 785 blkdev_reread_part(bdev); 786 if (nbd->disconnect) /* user requested, ignore socket errors */ 787 return 0; 788 return error; 789 } 790 791 case NBD_CLEAR_QUE: 792 /* 793 * This is for compatibility only. The queue is always cleared 794 * by NBD_DO_IT or NBD_CLEAR_SOCK. 795 */ 796 return 0; 797 798 case NBD_PRINT_DEBUG: 799 dev_info(disk_to_dev(nbd->disk), 800 "next = %p, prev = %p, head = %p\n", 801 nbd->queue_head.next, nbd->queue_head.prev, 802 &nbd->queue_head); 803 return 0; 804 } 805 return -ENOTTY; 806 } 807 808 static int nbd_ioctl(struct block_device *bdev, fmode_t mode, 809 unsigned int cmd, unsigned long arg) 810 { 811 struct nbd_device *nbd = bdev->bd_disk->private_data; 812 int error; 813 814 if (!capable(CAP_SYS_ADMIN)) 815 return -EPERM; 816 817 BUG_ON(nbd->magic != NBD_MAGIC); 818 819 mutex_lock(&nbd->tx_lock); 820 error = __nbd_ioctl(bdev, nbd, cmd, arg); 821 mutex_unlock(&nbd->tx_lock); 822 823 return error; 824 } 825 826 static const struct block_device_operations nbd_fops = 827 { 828 .owner = THIS_MODULE, 829 .ioctl = nbd_ioctl, 830 .compat_ioctl = nbd_ioctl, 831 }; 832 833 #if IS_ENABLED(CONFIG_DEBUG_FS) 834 835 static int nbd_dbg_tasks_show(struct seq_file *s, void *unused) 836 { 837 struct nbd_device *nbd = s->private; 838 839 if (nbd->task_recv) 840 seq_printf(s, "recv: %d\n", task_pid_nr(nbd->task_recv)); 841 if (nbd->task_send) 842 seq_printf(s, "send: %d\n", task_pid_nr(nbd->task_send)); 843 844 return 0; 845 } 846 847 static int nbd_dbg_tasks_open(struct inode *inode, struct file *file) 848 { 849 return single_open(file, nbd_dbg_tasks_show, inode->i_private); 850 } 851 852 static const struct file_operations nbd_dbg_tasks_ops = { 853 .open = nbd_dbg_tasks_open, 854 .read = seq_read, 855 .llseek = seq_lseek, 856 .release = single_release, 857 }; 858 859 static int nbd_dbg_flags_show(struct seq_file *s, void *unused) 860 { 861 struct nbd_device *nbd = s->private; 862 u32 flags = nbd->flags; 863 864 seq_printf(s, "Hex: 0x%08x\n\n", flags); 865 866 seq_puts(s, "Known flags:\n"); 867 868 if (flags & NBD_FLAG_HAS_FLAGS) 869 seq_puts(s, "NBD_FLAG_HAS_FLAGS\n"); 870 if (flags & NBD_FLAG_READ_ONLY) 871 seq_puts(s, "NBD_FLAG_READ_ONLY\n"); 872 if (flags & NBD_FLAG_SEND_FLUSH) 873 seq_puts(s, "NBD_FLAG_SEND_FLUSH\n"); 874 if (flags & NBD_FLAG_SEND_TRIM) 875 seq_puts(s, "NBD_FLAG_SEND_TRIM\n"); 876 877 return 0; 878 } 879 880 static int nbd_dbg_flags_open(struct inode *inode, struct file *file) 881 { 882 return single_open(file, nbd_dbg_flags_show, inode->i_private); 883 } 884 885 static const struct file_operations nbd_dbg_flags_ops = { 886 .open = nbd_dbg_flags_open, 887 .read = seq_read, 888 .llseek = seq_lseek, 889 .release = single_release, 890 }; 891 892 static int nbd_dev_dbg_init(struct nbd_device *nbd) 893 { 894 struct dentry *dir; 895 struct dentry *f; 896 897 dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir); 898 if (IS_ERR_OR_NULL(dir)) { 899 dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s' (%ld)\n", 900 nbd_name(nbd), PTR_ERR(dir)); 901 return PTR_ERR(dir); 902 } 903 nbd->dbg_dir = dir; 904 905 f = debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_ops); 906 if (IS_ERR_OR_NULL(f)) { 907 dev_err(nbd_to_dev(nbd), "Failed to create debugfs file 'tasks', %ld\n", 908 PTR_ERR(f)); 909 return PTR_ERR(f); 910 } 911 912 f = debugfs_create_u64("size_bytes", 0444, dir, &nbd->bytesize); 913 if (IS_ERR_OR_NULL(f)) { 914 dev_err(nbd_to_dev(nbd), "Failed to create debugfs file 'size_bytes', %ld\n", 915 PTR_ERR(f)); 916 return PTR_ERR(f); 917 } 918 919 f = debugfs_create_u32("timeout", 0444, dir, &nbd->xmit_timeout); 920 if (IS_ERR_OR_NULL(f)) { 921 dev_err(nbd_to_dev(nbd), "Failed to create debugfs file 'timeout', %ld\n", 922 PTR_ERR(f)); 923 return PTR_ERR(f); 924 } 925 926 f = debugfs_create_u32("blocksize", 0444, dir, &nbd->blksize); 927 if (IS_ERR_OR_NULL(f)) { 928 dev_err(nbd_to_dev(nbd), "Failed to create debugfs file 'blocksize', %ld\n", 929 PTR_ERR(f)); 930 return PTR_ERR(f); 931 } 932 933 f = debugfs_create_file("flags", 0444, dir, &nbd, &nbd_dbg_flags_ops); 934 if (IS_ERR_OR_NULL(f)) { 935 dev_err(nbd_to_dev(nbd), "Failed to create debugfs file 'flags', %ld\n", 936 PTR_ERR(f)); 937 return PTR_ERR(f); 938 } 939 940 return 0; 941 } 942 943 static void nbd_dev_dbg_close(struct nbd_device *nbd) 944 { 945 debugfs_remove_recursive(nbd->dbg_dir); 946 } 947 948 static int nbd_dbg_init(void) 949 { 950 struct dentry *dbg_dir; 951 952 dbg_dir = debugfs_create_dir("nbd", NULL); 953 if (IS_ERR(dbg_dir)) 954 return PTR_ERR(dbg_dir); 955 956 nbd_dbg_dir = dbg_dir; 957 958 return 0; 959 } 960 961 static void nbd_dbg_close(void) 962 { 963 debugfs_remove_recursive(nbd_dbg_dir); 964 } 965 966 #else /* IS_ENABLED(CONFIG_DEBUG_FS) */ 967 968 static int nbd_dev_dbg_init(struct nbd_device *nbd) 969 { 970 return 0; 971 } 972 973 static void nbd_dev_dbg_close(struct nbd_device *nbd) 974 { 975 } 976 977 static int nbd_dbg_init(void) 978 { 979 return 0; 980 } 981 982 static void nbd_dbg_close(void) 983 { 984 } 985 986 #endif 987 988 /* 989 * And here should be modules and kernel interface 990 * (Just smiley confuses emacs :-) 991 */ 992 993 static int __init nbd_init(void) 994 { 995 int err = -ENOMEM; 996 int i; 997 int part_shift; 998 999 BUILD_BUG_ON(sizeof(struct nbd_request) != 28); 1000 1001 if (max_part < 0) { 1002 printk(KERN_ERR "nbd: max_part must be >= 0\n"); 1003 return -EINVAL; 1004 } 1005 1006 part_shift = 0; 1007 if (max_part > 0) { 1008 part_shift = fls(max_part); 1009 1010 /* 1011 * Adjust max_part according to part_shift as it is exported 1012 * to user space so that user can know the max number of 1013 * partition kernel should be able to manage. 1014 * 1015 * Note that -1 is required because partition 0 is reserved 1016 * for the whole disk. 1017 */ 1018 max_part = (1UL << part_shift) - 1; 1019 } 1020 1021 if ((1UL << part_shift) > DISK_MAX_PARTS) 1022 return -EINVAL; 1023 1024 if (nbds_max > 1UL << (MINORBITS - part_shift)) 1025 return -EINVAL; 1026 1027 nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL); 1028 if (!nbd_dev) 1029 return -ENOMEM; 1030 1031 for (i = 0; i < nbds_max; i++) { 1032 struct gendisk *disk = alloc_disk(1 << part_shift); 1033 if (!disk) 1034 goto out; 1035 nbd_dev[i].disk = disk; 1036 /* 1037 * The new linux 2.5 block layer implementation requires 1038 * every gendisk to have its very own request_queue struct. 1039 * These structs are big so we dynamically allocate them. 1040 */ 1041 disk->queue = blk_init_queue(nbd_request_handler, &nbd_lock); 1042 if (!disk->queue) { 1043 put_disk(disk); 1044 goto out; 1045 } 1046 /* 1047 * Tell the block layer that we are not a rotational device 1048 */ 1049 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue); 1050 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, disk->queue); 1051 disk->queue->limits.discard_granularity = 512; 1052 blk_queue_max_discard_sectors(disk->queue, UINT_MAX); 1053 disk->queue->limits.discard_zeroes_data = 0; 1054 blk_queue_max_hw_sectors(disk->queue, 65536); 1055 disk->queue->limits.max_sectors = 256; 1056 } 1057 1058 if (register_blkdev(NBD_MAJOR, "nbd")) { 1059 err = -EIO; 1060 goto out; 1061 } 1062 1063 printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR); 1064 1065 nbd_dbg_init(); 1066 1067 for (i = 0; i < nbds_max; i++) { 1068 struct gendisk *disk = nbd_dev[i].disk; 1069 nbd_dev[i].magic = NBD_MAGIC; 1070 INIT_LIST_HEAD(&nbd_dev[i].waiting_queue); 1071 spin_lock_init(&nbd_dev[i].queue_lock); 1072 spin_lock_init(&nbd_dev[i].tasks_lock); 1073 INIT_LIST_HEAD(&nbd_dev[i].queue_head); 1074 mutex_init(&nbd_dev[i].tx_lock); 1075 init_timer(&nbd_dev[i].timeout_timer); 1076 nbd_dev[i].timeout_timer.function = nbd_xmit_timeout; 1077 nbd_dev[i].timeout_timer.data = (unsigned long)&nbd_dev[i]; 1078 init_waitqueue_head(&nbd_dev[i].active_wq); 1079 init_waitqueue_head(&nbd_dev[i].waiting_wq); 1080 nbd_dev[i].blksize = 1024; 1081 nbd_dev[i].bytesize = 0; 1082 disk->major = NBD_MAJOR; 1083 disk->first_minor = i << part_shift; 1084 disk->fops = &nbd_fops; 1085 disk->private_data = &nbd_dev[i]; 1086 sprintf(disk->disk_name, "nbd%d", i); 1087 set_capacity(disk, 0); 1088 add_disk(disk); 1089 } 1090 1091 return 0; 1092 out: 1093 while (i--) { 1094 blk_cleanup_queue(nbd_dev[i].disk->queue); 1095 put_disk(nbd_dev[i].disk); 1096 } 1097 kfree(nbd_dev); 1098 return err; 1099 } 1100 1101 static void __exit nbd_cleanup(void) 1102 { 1103 int i; 1104 1105 nbd_dbg_close(); 1106 1107 for (i = 0; i < nbds_max; i++) { 1108 struct gendisk *disk = nbd_dev[i].disk; 1109 nbd_dev[i].magic = 0; 1110 if (disk) { 1111 del_gendisk(disk); 1112 blk_cleanup_queue(disk->queue); 1113 put_disk(disk); 1114 } 1115 } 1116 unregister_blkdev(NBD_MAJOR, "nbd"); 1117 kfree(nbd_dev); 1118 printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR); 1119 } 1120 1121 module_init(nbd_init); 1122 module_exit(nbd_cleanup); 1123 1124 MODULE_DESCRIPTION("Network Block Device"); 1125 MODULE_LICENSE("GPL"); 1126 1127 module_param(nbds_max, int, 0444); 1128 MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)"); 1129 module_param(max_part, int, 0444); 1130 MODULE_PARM_DESC(max_part, "number of partitions per device (default: 0)"); 1131