1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Network block device - make block devices work over TCP 4 * 5 * Note that you can not swap over this thing, yet. Seems to work but 6 * deadlocks sometimes - you can not swap over TCP in general. 7 * 8 * Copyright 1997-2000, 2008 Pavel Machek <pavel@ucw.cz> 9 * Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com> 10 * 11 * (part of code stolen from loop.c) 12 */ 13 14 #include <linux/major.h> 15 16 #include <linux/blkdev.h> 17 #include <linux/module.h> 18 #include <linux/init.h> 19 #include <linux/sched.h> 20 #include <linux/sched/mm.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/completion.h> 30 #include <linux/err.h> 31 #include <linux/kernel.h> 32 #include <linux/slab.h> 33 #include <net/sock.h> 34 #include <linux/net.h> 35 #include <linux/kthread.h> 36 #include <linux/types.h> 37 #include <linux/debugfs.h> 38 #include <linux/blk-mq.h> 39 40 #include <linux/uaccess.h> 41 #include <asm/types.h> 42 43 #include <linux/nbd.h> 44 #include <linux/nbd-netlink.h> 45 #include <net/genetlink.h> 46 47 #define CREATE_TRACE_POINTS 48 #include <trace/events/nbd.h> 49 50 static DEFINE_IDR(nbd_index_idr); 51 static DEFINE_MUTEX(nbd_index_mutex); 52 static int nbd_total_devices = 0; 53 54 struct nbd_sock { 55 struct socket *sock; 56 struct mutex tx_lock; 57 struct request *pending; 58 int sent; 59 bool dead; 60 int fallback_index; 61 int cookie; 62 }; 63 64 struct recv_thread_args { 65 struct work_struct work; 66 struct nbd_device *nbd; 67 int index; 68 }; 69 70 struct link_dead_args { 71 struct work_struct work; 72 int index; 73 }; 74 75 #define NBD_RT_TIMEDOUT 0 76 #define NBD_RT_DISCONNECT_REQUESTED 1 77 #define NBD_RT_DISCONNECTED 2 78 #define NBD_RT_HAS_PID_FILE 3 79 #define NBD_RT_HAS_CONFIG_REF 4 80 #define NBD_RT_BOUND 5 81 #define NBD_RT_DESTROY_ON_DISCONNECT 6 82 #define NBD_RT_DISCONNECT_ON_CLOSE 7 83 84 #define NBD_DESTROY_ON_DISCONNECT 0 85 #define NBD_DISCONNECT_REQUESTED 1 86 87 struct nbd_config { 88 u32 flags; 89 unsigned long runtime_flags; 90 u64 dead_conn_timeout; 91 92 struct nbd_sock **socks; 93 int num_connections; 94 atomic_t live_connections; 95 wait_queue_head_t conn_wait; 96 97 atomic_t recv_threads; 98 wait_queue_head_t recv_wq; 99 loff_t blksize; 100 loff_t bytesize; 101 #if IS_ENABLED(CONFIG_DEBUG_FS) 102 struct dentry *dbg_dir; 103 #endif 104 }; 105 106 struct nbd_device { 107 struct blk_mq_tag_set tag_set; 108 109 int index; 110 refcount_t config_refs; 111 refcount_t refs; 112 struct nbd_config *config; 113 struct mutex config_lock; 114 struct gendisk *disk; 115 struct workqueue_struct *recv_workq; 116 117 struct list_head list; 118 struct task_struct *task_recv; 119 struct task_struct *task_setup; 120 121 struct completion *destroy_complete; 122 unsigned long flags; 123 }; 124 125 #define NBD_CMD_REQUEUED 1 126 127 struct nbd_cmd { 128 struct nbd_device *nbd; 129 struct mutex lock; 130 int index; 131 int cookie; 132 int retries; 133 blk_status_t status; 134 unsigned long flags; 135 u32 cmd_cookie; 136 }; 137 138 #if IS_ENABLED(CONFIG_DEBUG_FS) 139 static struct dentry *nbd_dbg_dir; 140 #endif 141 142 #define nbd_name(nbd) ((nbd)->disk->disk_name) 143 144 #define NBD_MAGIC 0x68797548 145 146 #define NBD_DEF_BLKSIZE 1024 147 148 static unsigned int nbds_max = 16; 149 static int max_part = 16; 150 static int part_shift; 151 152 static int nbd_dev_dbg_init(struct nbd_device *nbd); 153 static void nbd_dev_dbg_close(struct nbd_device *nbd); 154 static void nbd_config_put(struct nbd_device *nbd); 155 static void nbd_connect_reply(struct genl_info *info, int index); 156 static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info); 157 static void nbd_dead_link_work(struct work_struct *work); 158 static void nbd_disconnect_and_put(struct nbd_device *nbd); 159 160 static inline struct device *nbd_to_dev(struct nbd_device *nbd) 161 { 162 return disk_to_dev(nbd->disk); 163 } 164 165 static void nbd_requeue_cmd(struct nbd_cmd *cmd) 166 { 167 struct request *req = blk_mq_rq_from_pdu(cmd); 168 169 if (!test_and_set_bit(NBD_CMD_REQUEUED, &cmd->flags)) 170 blk_mq_requeue_request(req, true); 171 } 172 173 #define NBD_COOKIE_BITS 32 174 175 static u64 nbd_cmd_handle(struct nbd_cmd *cmd) 176 { 177 struct request *req = blk_mq_rq_from_pdu(cmd); 178 u32 tag = blk_mq_unique_tag(req); 179 u64 cookie = cmd->cmd_cookie; 180 181 return (cookie << NBD_COOKIE_BITS) | tag; 182 } 183 184 static u32 nbd_handle_to_tag(u64 handle) 185 { 186 return (u32)handle; 187 } 188 189 static u32 nbd_handle_to_cookie(u64 handle) 190 { 191 return (u32)(handle >> NBD_COOKIE_BITS); 192 } 193 194 static const char *nbdcmd_to_ascii(int cmd) 195 { 196 switch (cmd) { 197 case NBD_CMD_READ: return "read"; 198 case NBD_CMD_WRITE: return "write"; 199 case NBD_CMD_DISC: return "disconnect"; 200 case NBD_CMD_FLUSH: return "flush"; 201 case NBD_CMD_TRIM: return "trim/discard"; 202 } 203 return "invalid"; 204 } 205 206 static ssize_t pid_show(struct device *dev, 207 struct device_attribute *attr, char *buf) 208 { 209 struct gendisk *disk = dev_to_disk(dev); 210 struct nbd_device *nbd = (struct nbd_device *)disk->private_data; 211 212 return sprintf(buf, "%d\n", task_pid_nr(nbd->task_recv)); 213 } 214 215 static const struct device_attribute pid_attr = { 216 .attr = { .name = "pid", .mode = 0444}, 217 .show = pid_show, 218 }; 219 220 static void nbd_dev_remove(struct nbd_device *nbd) 221 { 222 struct gendisk *disk = nbd->disk; 223 struct request_queue *q; 224 225 if (disk) { 226 q = disk->queue; 227 del_gendisk(disk); 228 blk_cleanup_queue(q); 229 blk_mq_free_tag_set(&nbd->tag_set); 230 disk->private_data = NULL; 231 put_disk(disk); 232 } 233 234 /* 235 * Place this in the last just before the nbd is freed to 236 * make sure that the disk and the related kobject are also 237 * totally removed to avoid duplicate creation of the same 238 * one. 239 */ 240 if (test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags) && nbd->destroy_complete) 241 complete(nbd->destroy_complete); 242 243 kfree(nbd); 244 } 245 246 static void nbd_put(struct nbd_device *nbd) 247 { 248 if (refcount_dec_and_mutex_lock(&nbd->refs, 249 &nbd_index_mutex)) { 250 idr_remove(&nbd_index_idr, nbd->index); 251 nbd_dev_remove(nbd); 252 mutex_unlock(&nbd_index_mutex); 253 } 254 } 255 256 static int nbd_disconnected(struct nbd_config *config) 257 { 258 return test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags) || 259 test_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags); 260 } 261 262 static void nbd_mark_nsock_dead(struct nbd_device *nbd, struct nbd_sock *nsock, 263 int notify) 264 { 265 if (!nsock->dead && notify && !nbd_disconnected(nbd->config)) { 266 struct link_dead_args *args; 267 args = kmalloc(sizeof(struct link_dead_args), GFP_NOIO); 268 if (args) { 269 INIT_WORK(&args->work, nbd_dead_link_work); 270 args->index = nbd->index; 271 queue_work(system_wq, &args->work); 272 } 273 } 274 if (!nsock->dead) { 275 kernel_sock_shutdown(nsock->sock, SHUT_RDWR); 276 if (atomic_dec_return(&nbd->config->live_connections) == 0) { 277 if (test_and_clear_bit(NBD_RT_DISCONNECT_REQUESTED, 278 &nbd->config->runtime_flags)) { 279 set_bit(NBD_RT_DISCONNECTED, 280 &nbd->config->runtime_flags); 281 dev_info(nbd_to_dev(nbd), 282 "Disconnected due to user request.\n"); 283 } 284 } 285 } 286 nsock->dead = true; 287 nsock->pending = NULL; 288 nsock->sent = 0; 289 } 290 291 static void nbd_size_clear(struct nbd_device *nbd) 292 { 293 if (nbd->config->bytesize) { 294 set_capacity(nbd->disk, 0); 295 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE); 296 } 297 } 298 299 static void nbd_size_update(struct nbd_device *nbd, bool start) 300 { 301 struct nbd_config *config = nbd->config; 302 struct block_device *bdev = bdget_disk(nbd->disk, 0); 303 sector_t nr_sectors = config->bytesize >> 9; 304 305 if (config->flags & NBD_FLAG_SEND_TRIM) { 306 nbd->disk->queue->limits.discard_granularity = config->blksize; 307 nbd->disk->queue->limits.discard_alignment = config->blksize; 308 blk_queue_max_discard_sectors(nbd->disk->queue, UINT_MAX); 309 } 310 blk_queue_logical_block_size(nbd->disk->queue, config->blksize); 311 blk_queue_physical_block_size(nbd->disk->queue, config->blksize); 312 set_capacity(nbd->disk, nr_sectors); 313 if (bdev) { 314 if (bdev->bd_disk) { 315 bd_set_nr_sectors(bdev, nr_sectors); 316 if (start) 317 set_blocksize(bdev, config->blksize); 318 } else 319 set_bit(GD_NEED_PART_SCAN, &nbd->disk->state); 320 bdput(bdev); 321 } 322 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE); 323 } 324 325 static void nbd_size_set(struct nbd_device *nbd, loff_t blocksize, 326 loff_t nr_blocks) 327 { 328 struct nbd_config *config = nbd->config; 329 config->blksize = blocksize; 330 config->bytesize = blocksize * nr_blocks; 331 if (nbd->task_recv != NULL) 332 nbd_size_update(nbd, false); 333 } 334 335 static void nbd_complete_rq(struct request *req) 336 { 337 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req); 338 339 dev_dbg(nbd_to_dev(cmd->nbd), "request %p: %s\n", req, 340 cmd->status ? "failed" : "done"); 341 342 blk_mq_end_request(req, cmd->status); 343 } 344 345 /* 346 * Forcibly shutdown the socket causing all listeners to error 347 */ 348 static void sock_shutdown(struct nbd_device *nbd) 349 { 350 struct nbd_config *config = nbd->config; 351 int i; 352 353 if (config->num_connections == 0) 354 return; 355 if (test_and_set_bit(NBD_RT_DISCONNECTED, &config->runtime_flags)) 356 return; 357 358 for (i = 0; i < config->num_connections; i++) { 359 struct nbd_sock *nsock = config->socks[i]; 360 mutex_lock(&nsock->tx_lock); 361 nbd_mark_nsock_dead(nbd, nsock, 0); 362 mutex_unlock(&nsock->tx_lock); 363 } 364 dev_warn(disk_to_dev(nbd->disk), "shutting down sockets\n"); 365 } 366 367 static u32 req_to_nbd_cmd_type(struct request *req) 368 { 369 switch (req_op(req)) { 370 case REQ_OP_DISCARD: 371 return NBD_CMD_TRIM; 372 case REQ_OP_FLUSH: 373 return NBD_CMD_FLUSH; 374 case REQ_OP_WRITE: 375 return NBD_CMD_WRITE; 376 case REQ_OP_READ: 377 return NBD_CMD_READ; 378 default: 379 return U32_MAX; 380 } 381 } 382 383 static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req, 384 bool reserved) 385 { 386 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req); 387 struct nbd_device *nbd = cmd->nbd; 388 struct nbd_config *config; 389 390 if (!mutex_trylock(&cmd->lock)) 391 return BLK_EH_RESET_TIMER; 392 393 if (!refcount_inc_not_zero(&nbd->config_refs)) { 394 cmd->status = BLK_STS_TIMEOUT; 395 mutex_unlock(&cmd->lock); 396 goto done; 397 } 398 config = nbd->config; 399 400 if (config->num_connections > 1 || 401 (config->num_connections == 1 && nbd->tag_set.timeout)) { 402 dev_err_ratelimited(nbd_to_dev(nbd), 403 "Connection timed out, retrying (%d/%d alive)\n", 404 atomic_read(&config->live_connections), 405 config->num_connections); 406 /* 407 * Hooray we have more connections, requeue this IO, the submit 408 * path will put it on a real connection. Or if only one 409 * connection is configured, the submit path will wait util 410 * a new connection is reconfigured or util dead timeout. 411 */ 412 if (config->socks) { 413 if (cmd->index < config->num_connections) { 414 struct nbd_sock *nsock = 415 config->socks[cmd->index]; 416 mutex_lock(&nsock->tx_lock); 417 /* We can have multiple outstanding requests, so 418 * we don't want to mark the nsock dead if we've 419 * already reconnected with a new socket, so 420 * only mark it dead if its the same socket we 421 * were sent out on. 422 */ 423 if (cmd->cookie == nsock->cookie) 424 nbd_mark_nsock_dead(nbd, nsock, 1); 425 mutex_unlock(&nsock->tx_lock); 426 } 427 mutex_unlock(&cmd->lock); 428 nbd_requeue_cmd(cmd); 429 nbd_config_put(nbd); 430 return BLK_EH_DONE; 431 } 432 } 433 434 if (!nbd->tag_set.timeout) { 435 /* 436 * Userspace sets timeout=0 to disable socket disconnection, 437 * so just warn and reset the timer. 438 */ 439 struct nbd_sock *nsock = config->socks[cmd->index]; 440 cmd->retries++; 441 dev_info(nbd_to_dev(nbd), "Possible stuck request %p: control (%s@%llu,%uB). Runtime %u seconds\n", 442 req, nbdcmd_to_ascii(req_to_nbd_cmd_type(req)), 443 (unsigned long long)blk_rq_pos(req) << 9, 444 blk_rq_bytes(req), (req->timeout / HZ) * cmd->retries); 445 446 mutex_lock(&nsock->tx_lock); 447 if (cmd->cookie != nsock->cookie) { 448 nbd_requeue_cmd(cmd); 449 mutex_unlock(&nsock->tx_lock); 450 mutex_unlock(&cmd->lock); 451 nbd_config_put(nbd); 452 return BLK_EH_DONE; 453 } 454 mutex_unlock(&nsock->tx_lock); 455 mutex_unlock(&cmd->lock); 456 nbd_config_put(nbd); 457 return BLK_EH_RESET_TIMER; 458 } 459 460 dev_err_ratelimited(nbd_to_dev(nbd), "Connection timed out\n"); 461 set_bit(NBD_RT_TIMEDOUT, &config->runtime_flags); 462 cmd->status = BLK_STS_IOERR; 463 mutex_unlock(&cmd->lock); 464 sock_shutdown(nbd); 465 nbd_config_put(nbd); 466 done: 467 blk_mq_complete_request(req); 468 return BLK_EH_DONE; 469 } 470 471 /* 472 * Send or receive packet. 473 */ 474 static int sock_xmit(struct nbd_device *nbd, int index, int send, 475 struct iov_iter *iter, int msg_flags, int *sent) 476 { 477 struct nbd_config *config = nbd->config; 478 struct socket *sock = config->socks[index]->sock; 479 int result; 480 struct msghdr msg; 481 unsigned int noreclaim_flag; 482 483 if (unlikely(!sock)) { 484 dev_err_ratelimited(disk_to_dev(nbd->disk), 485 "Attempted %s on closed socket in sock_xmit\n", 486 (send ? "send" : "recv")); 487 return -EINVAL; 488 } 489 490 msg.msg_iter = *iter; 491 492 noreclaim_flag = memalloc_noreclaim_save(); 493 do { 494 sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC; 495 msg.msg_name = NULL; 496 msg.msg_namelen = 0; 497 msg.msg_control = NULL; 498 msg.msg_controllen = 0; 499 msg.msg_flags = msg_flags | MSG_NOSIGNAL; 500 501 if (send) 502 result = sock_sendmsg(sock, &msg); 503 else 504 result = sock_recvmsg(sock, &msg, msg.msg_flags); 505 506 if (result <= 0) { 507 if (result == 0) 508 result = -EPIPE; /* short read */ 509 break; 510 } 511 if (sent) 512 *sent += result; 513 } while (msg_data_left(&msg)); 514 515 memalloc_noreclaim_restore(noreclaim_flag); 516 517 return result; 518 } 519 520 /* 521 * Different settings for sk->sk_sndtimeo can result in different return values 522 * if there is a signal pending when we enter sendmsg, because reasons? 523 */ 524 static inline int was_interrupted(int result) 525 { 526 return result == -ERESTARTSYS || result == -EINTR; 527 } 528 529 /* always call with the tx_lock held */ 530 static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index) 531 { 532 struct request *req = blk_mq_rq_from_pdu(cmd); 533 struct nbd_config *config = nbd->config; 534 struct nbd_sock *nsock = config->socks[index]; 535 int result; 536 struct nbd_request request = {.magic = htonl(NBD_REQUEST_MAGIC)}; 537 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)}; 538 struct iov_iter from; 539 unsigned long size = blk_rq_bytes(req); 540 struct bio *bio; 541 u64 handle; 542 u32 type; 543 u32 nbd_cmd_flags = 0; 544 int sent = nsock->sent, skip = 0; 545 546 iov_iter_kvec(&from, WRITE, &iov, 1, sizeof(request)); 547 548 type = req_to_nbd_cmd_type(req); 549 if (type == U32_MAX) 550 return -EIO; 551 552 if (rq_data_dir(req) == WRITE && 553 (config->flags & NBD_FLAG_READ_ONLY)) { 554 dev_err_ratelimited(disk_to_dev(nbd->disk), 555 "Write on read-only\n"); 556 return -EIO; 557 } 558 559 if (req->cmd_flags & REQ_FUA) 560 nbd_cmd_flags |= NBD_CMD_FLAG_FUA; 561 562 /* We did a partial send previously, and we at least sent the whole 563 * request struct, so just go and send the rest of the pages in the 564 * request. 565 */ 566 if (sent) { 567 if (sent >= sizeof(request)) { 568 skip = sent - sizeof(request); 569 570 /* initialize handle for tracing purposes */ 571 handle = nbd_cmd_handle(cmd); 572 573 goto send_pages; 574 } 575 iov_iter_advance(&from, sent); 576 } else { 577 cmd->cmd_cookie++; 578 } 579 cmd->index = index; 580 cmd->cookie = nsock->cookie; 581 cmd->retries = 0; 582 request.type = htonl(type | nbd_cmd_flags); 583 if (type != NBD_CMD_FLUSH) { 584 request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9); 585 request.len = htonl(size); 586 } 587 handle = nbd_cmd_handle(cmd); 588 memcpy(request.handle, &handle, sizeof(handle)); 589 590 trace_nbd_send_request(&request, nbd->index, blk_mq_rq_from_pdu(cmd)); 591 592 dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n", 593 req, nbdcmd_to_ascii(type), 594 (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req)); 595 result = sock_xmit(nbd, index, 1, &from, 596 (type == NBD_CMD_WRITE) ? MSG_MORE : 0, &sent); 597 trace_nbd_header_sent(req, handle); 598 if (result <= 0) { 599 if (was_interrupted(result)) { 600 /* If we havne't sent anything we can just return BUSY, 601 * however if we have sent something we need to make 602 * sure we only allow this req to be sent until we are 603 * completely done. 604 */ 605 if (sent) { 606 nsock->pending = req; 607 nsock->sent = sent; 608 } 609 set_bit(NBD_CMD_REQUEUED, &cmd->flags); 610 return BLK_STS_RESOURCE; 611 } 612 dev_err_ratelimited(disk_to_dev(nbd->disk), 613 "Send control failed (result %d)\n", result); 614 return -EAGAIN; 615 } 616 send_pages: 617 if (type != NBD_CMD_WRITE) 618 goto out; 619 620 bio = req->bio; 621 while (bio) { 622 struct bio *next = bio->bi_next; 623 struct bvec_iter iter; 624 struct bio_vec bvec; 625 626 bio_for_each_segment(bvec, bio, iter) { 627 bool is_last = !next && bio_iter_last(bvec, iter); 628 int flags = is_last ? 0 : MSG_MORE; 629 630 dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n", 631 req, bvec.bv_len); 632 iov_iter_bvec(&from, WRITE, &bvec, 1, bvec.bv_len); 633 if (skip) { 634 if (skip >= iov_iter_count(&from)) { 635 skip -= iov_iter_count(&from); 636 continue; 637 } 638 iov_iter_advance(&from, skip); 639 skip = 0; 640 } 641 result = sock_xmit(nbd, index, 1, &from, flags, &sent); 642 if (result <= 0) { 643 if (was_interrupted(result)) { 644 /* We've already sent the header, we 645 * have no choice but to set pending and 646 * return BUSY. 647 */ 648 nsock->pending = req; 649 nsock->sent = sent; 650 set_bit(NBD_CMD_REQUEUED, &cmd->flags); 651 return BLK_STS_RESOURCE; 652 } 653 dev_err(disk_to_dev(nbd->disk), 654 "Send data failed (result %d)\n", 655 result); 656 return -EAGAIN; 657 } 658 /* 659 * The completion might already have come in, 660 * so break for the last one instead of letting 661 * the iterator do it. This prevents use-after-free 662 * of the bio. 663 */ 664 if (is_last) 665 break; 666 } 667 bio = next; 668 } 669 out: 670 trace_nbd_payload_sent(req, handle); 671 nsock->pending = NULL; 672 nsock->sent = 0; 673 return 0; 674 } 675 676 /* NULL returned = something went wrong, inform userspace */ 677 static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index) 678 { 679 struct nbd_config *config = nbd->config; 680 int result; 681 struct nbd_reply reply; 682 struct nbd_cmd *cmd; 683 struct request *req = NULL; 684 u64 handle; 685 u16 hwq; 686 u32 tag; 687 struct kvec iov = {.iov_base = &reply, .iov_len = sizeof(reply)}; 688 struct iov_iter to; 689 int ret = 0; 690 691 reply.magic = 0; 692 iov_iter_kvec(&to, READ, &iov, 1, sizeof(reply)); 693 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL); 694 if (result <= 0) { 695 if (!nbd_disconnected(config)) 696 dev_err(disk_to_dev(nbd->disk), 697 "Receive control failed (result %d)\n", result); 698 return ERR_PTR(result); 699 } 700 701 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) { 702 dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n", 703 (unsigned long)ntohl(reply.magic)); 704 return ERR_PTR(-EPROTO); 705 } 706 707 memcpy(&handle, reply.handle, sizeof(handle)); 708 tag = nbd_handle_to_tag(handle); 709 hwq = blk_mq_unique_tag_to_hwq(tag); 710 if (hwq < nbd->tag_set.nr_hw_queues) 711 req = blk_mq_tag_to_rq(nbd->tag_set.tags[hwq], 712 blk_mq_unique_tag_to_tag(tag)); 713 if (!req || !blk_mq_request_started(req)) { 714 dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%d) %p\n", 715 tag, req); 716 return ERR_PTR(-ENOENT); 717 } 718 trace_nbd_header_received(req, handle); 719 cmd = blk_mq_rq_to_pdu(req); 720 721 mutex_lock(&cmd->lock); 722 if (cmd->cmd_cookie != nbd_handle_to_cookie(handle)) { 723 dev_err(disk_to_dev(nbd->disk), "Double reply on req %p, cmd_cookie %u, handle cookie %u\n", 724 req, cmd->cmd_cookie, nbd_handle_to_cookie(handle)); 725 ret = -ENOENT; 726 goto out; 727 } 728 if (cmd->status != BLK_STS_OK) { 729 dev_err(disk_to_dev(nbd->disk), "Command already handled %p\n", 730 req); 731 ret = -ENOENT; 732 goto out; 733 } 734 if (test_bit(NBD_CMD_REQUEUED, &cmd->flags)) { 735 dev_err(disk_to_dev(nbd->disk), "Raced with timeout on req %p\n", 736 req); 737 ret = -ENOENT; 738 goto out; 739 } 740 if (ntohl(reply.error)) { 741 dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n", 742 ntohl(reply.error)); 743 cmd->status = BLK_STS_IOERR; 744 goto out; 745 } 746 747 dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", req); 748 if (rq_data_dir(req) != WRITE) { 749 struct req_iterator iter; 750 struct bio_vec bvec; 751 752 rq_for_each_segment(bvec, req, iter) { 753 iov_iter_bvec(&to, READ, &bvec, 1, bvec.bv_len); 754 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL); 755 if (result <= 0) { 756 dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n", 757 result); 758 /* 759 * If we've disconnected, we need to make sure we 760 * complete this request, otherwise error out 761 * and let the timeout stuff handle resubmitting 762 * this request onto another connection. 763 */ 764 if (nbd_disconnected(config)) { 765 cmd->status = BLK_STS_IOERR; 766 goto out; 767 } 768 ret = -EIO; 769 goto out; 770 } 771 dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n", 772 req, bvec.bv_len); 773 } 774 } 775 out: 776 trace_nbd_payload_received(req, handle); 777 mutex_unlock(&cmd->lock); 778 return ret ? ERR_PTR(ret) : cmd; 779 } 780 781 static void recv_work(struct work_struct *work) 782 { 783 struct recv_thread_args *args = container_of(work, 784 struct recv_thread_args, 785 work); 786 struct nbd_device *nbd = args->nbd; 787 struct nbd_config *config = nbd->config; 788 struct nbd_cmd *cmd; 789 struct request *rq; 790 791 while (1) { 792 cmd = nbd_read_stat(nbd, args->index); 793 if (IS_ERR(cmd)) { 794 struct nbd_sock *nsock = config->socks[args->index]; 795 796 mutex_lock(&nsock->tx_lock); 797 nbd_mark_nsock_dead(nbd, nsock, 1); 798 mutex_unlock(&nsock->tx_lock); 799 break; 800 } 801 802 rq = blk_mq_rq_from_pdu(cmd); 803 if (likely(!blk_should_fake_timeout(rq->q))) 804 blk_mq_complete_request(rq); 805 } 806 nbd_config_put(nbd); 807 atomic_dec(&config->recv_threads); 808 wake_up(&config->recv_wq); 809 kfree(args); 810 } 811 812 static bool nbd_clear_req(struct request *req, void *data, bool reserved) 813 { 814 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req); 815 816 mutex_lock(&cmd->lock); 817 cmd->status = BLK_STS_IOERR; 818 mutex_unlock(&cmd->lock); 819 820 blk_mq_complete_request(req); 821 return true; 822 } 823 824 static void nbd_clear_que(struct nbd_device *nbd) 825 { 826 blk_mq_quiesce_queue(nbd->disk->queue); 827 blk_mq_tagset_busy_iter(&nbd->tag_set, nbd_clear_req, NULL); 828 blk_mq_unquiesce_queue(nbd->disk->queue); 829 dev_dbg(disk_to_dev(nbd->disk), "queue cleared\n"); 830 } 831 832 static int find_fallback(struct nbd_device *nbd, int index) 833 { 834 struct nbd_config *config = nbd->config; 835 int new_index = -1; 836 struct nbd_sock *nsock = config->socks[index]; 837 int fallback = nsock->fallback_index; 838 839 if (test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags)) 840 return new_index; 841 842 if (config->num_connections <= 1) { 843 dev_err_ratelimited(disk_to_dev(nbd->disk), 844 "Dead connection, failed to find a fallback\n"); 845 return new_index; 846 } 847 848 if (fallback >= 0 && fallback < config->num_connections && 849 !config->socks[fallback]->dead) 850 return fallback; 851 852 if (nsock->fallback_index < 0 || 853 nsock->fallback_index >= config->num_connections || 854 config->socks[nsock->fallback_index]->dead) { 855 int i; 856 for (i = 0; i < config->num_connections; i++) { 857 if (i == index) 858 continue; 859 if (!config->socks[i]->dead) { 860 new_index = i; 861 break; 862 } 863 } 864 nsock->fallback_index = new_index; 865 if (new_index < 0) { 866 dev_err_ratelimited(disk_to_dev(nbd->disk), 867 "Dead connection, failed to find a fallback\n"); 868 return new_index; 869 } 870 } 871 new_index = nsock->fallback_index; 872 return new_index; 873 } 874 875 static int wait_for_reconnect(struct nbd_device *nbd) 876 { 877 struct nbd_config *config = nbd->config; 878 if (!config->dead_conn_timeout) 879 return 0; 880 if (test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags)) 881 return 0; 882 return wait_event_timeout(config->conn_wait, 883 atomic_read(&config->live_connections) > 0, 884 config->dead_conn_timeout) > 0; 885 } 886 887 static int nbd_handle_cmd(struct nbd_cmd *cmd, int index) 888 { 889 struct request *req = blk_mq_rq_from_pdu(cmd); 890 struct nbd_device *nbd = cmd->nbd; 891 struct nbd_config *config; 892 struct nbd_sock *nsock; 893 int ret; 894 895 if (!refcount_inc_not_zero(&nbd->config_refs)) { 896 dev_err_ratelimited(disk_to_dev(nbd->disk), 897 "Socks array is empty\n"); 898 blk_mq_start_request(req); 899 return -EINVAL; 900 } 901 config = nbd->config; 902 903 if (index >= config->num_connections) { 904 dev_err_ratelimited(disk_to_dev(nbd->disk), 905 "Attempted send on invalid socket\n"); 906 nbd_config_put(nbd); 907 blk_mq_start_request(req); 908 return -EINVAL; 909 } 910 cmd->status = BLK_STS_OK; 911 again: 912 nsock = config->socks[index]; 913 mutex_lock(&nsock->tx_lock); 914 if (nsock->dead) { 915 int old_index = index; 916 index = find_fallback(nbd, index); 917 mutex_unlock(&nsock->tx_lock); 918 if (index < 0) { 919 if (wait_for_reconnect(nbd)) { 920 index = old_index; 921 goto again; 922 } 923 /* All the sockets should already be down at this point, 924 * we just want to make sure that DISCONNECTED is set so 925 * any requests that come in that were queue'ed waiting 926 * for the reconnect timer don't trigger the timer again 927 * and instead just error out. 928 */ 929 sock_shutdown(nbd); 930 nbd_config_put(nbd); 931 blk_mq_start_request(req); 932 return -EIO; 933 } 934 goto again; 935 } 936 937 /* Handle the case that we have a pending request that was partially 938 * transmitted that _has_ to be serviced first. We need to call requeue 939 * here so that it gets put _after_ the request that is already on the 940 * dispatch list. 941 */ 942 blk_mq_start_request(req); 943 if (unlikely(nsock->pending && nsock->pending != req)) { 944 nbd_requeue_cmd(cmd); 945 ret = 0; 946 goto out; 947 } 948 /* 949 * Some failures are related to the link going down, so anything that 950 * returns EAGAIN can be retried on a different socket. 951 */ 952 ret = nbd_send_cmd(nbd, cmd, index); 953 if (ret == -EAGAIN) { 954 dev_err_ratelimited(disk_to_dev(nbd->disk), 955 "Request send failed, requeueing\n"); 956 nbd_mark_nsock_dead(nbd, nsock, 1); 957 nbd_requeue_cmd(cmd); 958 ret = 0; 959 } 960 out: 961 mutex_unlock(&nsock->tx_lock); 962 nbd_config_put(nbd); 963 return ret; 964 } 965 966 static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx, 967 const struct blk_mq_queue_data *bd) 968 { 969 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(bd->rq); 970 int ret; 971 972 /* 973 * Since we look at the bio's to send the request over the network we 974 * need to make sure the completion work doesn't mark this request done 975 * before we are done doing our send. This keeps us from dereferencing 976 * freed data if we have particularly fast completions (ie we get the 977 * completion before we exit sock_xmit on the last bvec) or in the case 978 * that the server is misbehaving (or there was an error) before we're 979 * done sending everything over the wire. 980 */ 981 mutex_lock(&cmd->lock); 982 clear_bit(NBD_CMD_REQUEUED, &cmd->flags); 983 984 /* We can be called directly from the user space process, which means we 985 * could possibly have signals pending so our sendmsg will fail. In 986 * this case we need to return that we are busy, otherwise error out as 987 * appropriate. 988 */ 989 ret = nbd_handle_cmd(cmd, hctx->queue_num); 990 if (ret < 0) 991 ret = BLK_STS_IOERR; 992 else if (!ret) 993 ret = BLK_STS_OK; 994 mutex_unlock(&cmd->lock); 995 996 return ret; 997 } 998 999 static struct socket *nbd_get_socket(struct nbd_device *nbd, unsigned long fd, 1000 int *err) 1001 { 1002 struct socket *sock; 1003 1004 *err = 0; 1005 sock = sockfd_lookup(fd, err); 1006 if (!sock) 1007 return NULL; 1008 1009 if (sock->ops->shutdown == sock_no_shutdown) { 1010 dev_err(disk_to_dev(nbd->disk), "Unsupported socket: shutdown callout must be supported.\n"); 1011 *err = -EINVAL; 1012 sockfd_put(sock); 1013 return NULL; 1014 } 1015 1016 return sock; 1017 } 1018 1019 static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg, 1020 bool netlink) 1021 { 1022 struct nbd_config *config = nbd->config; 1023 struct socket *sock; 1024 struct nbd_sock **socks; 1025 struct nbd_sock *nsock; 1026 int err; 1027 1028 sock = nbd_get_socket(nbd, arg, &err); 1029 if (!sock) 1030 return err; 1031 1032 if (!netlink && !nbd->task_setup && 1033 !test_bit(NBD_RT_BOUND, &config->runtime_flags)) 1034 nbd->task_setup = current; 1035 1036 if (!netlink && 1037 (nbd->task_setup != current || 1038 test_bit(NBD_RT_BOUND, &config->runtime_flags))) { 1039 dev_err(disk_to_dev(nbd->disk), 1040 "Device being setup by another task"); 1041 err = -EBUSY; 1042 goto put_socket; 1043 } 1044 1045 nsock = kzalloc(sizeof(*nsock), GFP_KERNEL); 1046 if (!nsock) { 1047 err = -ENOMEM; 1048 goto put_socket; 1049 } 1050 1051 socks = krealloc(config->socks, (config->num_connections + 1) * 1052 sizeof(struct nbd_sock *), GFP_KERNEL); 1053 if (!socks) { 1054 kfree(nsock); 1055 err = -ENOMEM; 1056 goto put_socket; 1057 } 1058 1059 config->socks = socks; 1060 1061 nsock->fallback_index = -1; 1062 nsock->dead = false; 1063 mutex_init(&nsock->tx_lock); 1064 nsock->sock = sock; 1065 nsock->pending = NULL; 1066 nsock->sent = 0; 1067 nsock->cookie = 0; 1068 socks[config->num_connections++] = nsock; 1069 atomic_inc(&config->live_connections); 1070 1071 return 0; 1072 1073 put_socket: 1074 sockfd_put(sock); 1075 return err; 1076 } 1077 1078 static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg) 1079 { 1080 struct nbd_config *config = nbd->config; 1081 struct socket *sock, *old; 1082 struct recv_thread_args *args; 1083 int i; 1084 int err; 1085 1086 sock = nbd_get_socket(nbd, arg, &err); 1087 if (!sock) 1088 return err; 1089 1090 args = kzalloc(sizeof(*args), GFP_KERNEL); 1091 if (!args) { 1092 sockfd_put(sock); 1093 return -ENOMEM; 1094 } 1095 1096 for (i = 0; i < config->num_connections; i++) { 1097 struct nbd_sock *nsock = config->socks[i]; 1098 1099 if (!nsock->dead) 1100 continue; 1101 1102 mutex_lock(&nsock->tx_lock); 1103 if (!nsock->dead) { 1104 mutex_unlock(&nsock->tx_lock); 1105 continue; 1106 } 1107 sk_set_memalloc(sock->sk); 1108 if (nbd->tag_set.timeout) 1109 sock->sk->sk_sndtimeo = nbd->tag_set.timeout; 1110 atomic_inc(&config->recv_threads); 1111 refcount_inc(&nbd->config_refs); 1112 old = nsock->sock; 1113 nsock->fallback_index = -1; 1114 nsock->sock = sock; 1115 nsock->dead = false; 1116 INIT_WORK(&args->work, recv_work); 1117 args->index = i; 1118 args->nbd = nbd; 1119 nsock->cookie++; 1120 mutex_unlock(&nsock->tx_lock); 1121 sockfd_put(old); 1122 1123 clear_bit(NBD_RT_DISCONNECTED, &config->runtime_flags); 1124 1125 /* We take the tx_mutex in an error path in the recv_work, so we 1126 * need to queue_work outside of the tx_mutex. 1127 */ 1128 queue_work(nbd->recv_workq, &args->work); 1129 1130 atomic_inc(&config->live_connections); 1131 wake_up(&config->conn_wait); 1132 return 0; 1133 } 1134 sockfd_put(sock); 1135 kfree(args); 1136 return -ENOSPC; 1137 } 1138 1139 static void nbd_bdev_reset(struct block_device *bdev) 1140 { 1141 if (bdev->bd_openers > 1) 1142 return; 1143 bd_set_nr_sectors(bdev, 0); 1144 } 1145 1146 static void nbd_parse_flags(struct nbd_device *nbd) 1147 { 1148 struct nbd_config *config = nbd->config; 1149 if (config->flags & NBD_FLAG_READ_ONLY) 1150 set_disk_ro(nbd->disk, true); 1151 else 1152 set_disk_ro(nbd->disk, false); 1153 if (config->flags & NBD_FLAG_SEND_TRIM) 1154 blk_queue_flag_set(QUEUE_FLAG_DISCARD, nbd->disk->queue); 1155 if (config->flags & NBD_FLAG_SEND_FLUSH) { 1156 if (config->flags & NBD_FLAG_SEND_FUA) 1157 blk_queue_write_cache(nbd->disk->queue, true, true); 1158 else 1159 blk_queue_write_cache(nbd->disk->queue, true, false); 1160 } 1161 else 1162 blk_queue_write_cache(nbd->disk->queue, false, false); 1163 } 1164 1165 static void send_disconnects(struct nbd_device *nbd) 1166 { 1167 struct nbd_config *config = nbd->config; 1168 struct nbd_request request = { 1169 .magic = htonl(NBD_REQUEST_MAGIC), 1170 .type = htonl(NBD_CMD_DISC), 1171 }; 1172 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)}; 1173 struct iov_iter from; 1174 int i, ret; 1175 1176 for (i = 0; i < config->num_connections; i++) { 1177 struct nbd_sock *nsock = config->socks[i]; 1178 1179 iov_iter_kvec(&from, WRITE, &iov, 1, sizeof(request)); 1180 mutex_lock(&nsock->tx_lock); 1181 ret = sock_xmit(nbd, i, 1, &from, 0, NULL); 1182 if (ret <= 0) 1183 dev_err(disk_to_dev(nbd->disk), 1184 "Send disconnect failed %d\n", ret); 1185 mutex_unlock(&nsock->tx_lock); 1186 } 1187 } 1188 1189 static int nbd_disconnect(struct nbd_device *nbd) 1190 { 1191 struct nbd_config *config = nbd->config; 1192 1193 dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n"); 1194 set_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags); 1195 set_bit(NBD_DISCONNECT_REQUESTED, &nbd->flags); 1196 send_disconnects(nbd); 1197 return 0; 1198 } 1199 1200 static void nbd_clear_sock(struct nbd_device *nbd) 1201 { 1202 sock_shutdown(nbd); 1203 nbd_clear_que(nbd); 1204 nbd->task_setup = NULL; 1205 } 1206 1207 static void nbd_config_put(struct nbd_device *nbd) 1208 { 1209 if (refcount_dec_and_mutex_lock(&nbd->config_refs, 1210 &nbd->config_lock)) { 1211 struct nbd_config *config = nbd->config; 1212 nbd_dev_dbg_close(nbd); 1213 nbd_size_clear(nbd); 1214 if (test_and_clear_bit(NBD_RT_HAS_PID_FILE, 1215 &config->runtime_flags)) 1216 device_remove_file(disk_to_dev(nbd->disk), &pid_attr); 1217 nbd->task_recv = NULL; 1218 nbd_clear_sock(nbd); 1219 if (config->num_connections) { 1220 int i; 1221 for (i = 0; i < config->num_connections; i++) { 1222 sockfd_put(config->socks[i]->sock); 1223 kfree(config->socks[i]); 1224 } 1225 kfree(config->socks); 1226 } 1227 kfree(nbd->config); 1228 nbd->config = NULL; 1229 1230 if (nbd->recv_workq) 1231 destroy_workqueue(nbd->recv_workq); 1232 nbd->recv_workq = NULL; 1233 1234 nbd->tag_set.timeout = 0; 1235 nbd->disk->queue->limits.discard_granularity = 0; 1236 nbd->disk->queue->limits.discard_alignment = 0; 1237 blk_queue_max_discard_sectors(nbd->disk->queue, UINT_MAX); 1238 blk_queue_flag_clear(QUEUE_FLAG_DISCARD, nbd->disk->queue); 1239 1240 mutex_unlock(&nbd->config_lock); 1241 nbd_put(nbd); 1242 module_put(THIS_MODULE); 1243 } 1244 } 1245 1246 static int nbd_start_device(struct nbd_device *nbd) 1247 { 1248 struct nbd_config *config = nbd->config; 1249 int num_connections = config->num_connections; 1250 int error = 0, i; 1251 1252 if (nbd->task_recv) 1253 return -EBUSY; 1254 if (!config->socks) 1255 return -EINVAL; 1256 if (num_connections > 1 && 1257 !(config->flags & NBD_FLAG_CAN_MULTI_CONN)) { 1258 dev_err(disk_to_dev(nbd->disk), "server does not support multiple connections per device.\n"); 1259 return -EINVAL; 1260 } 1261 1262 nbd->recv_workq = alloc_workqueue("knbd%d-recv", 1263 WQ_MEM_RECLAIM | WQ_HIGHPRI | 1264 WQ_UNBOUND, 0, nbd->index); 1265 if (!nbd->recv_workq) { 1266 dev_err(disk_to_dev(nbd->disk), "Could not allocate knbd recv work queue.\n"); 1267 return -ENOMEM; 1268 } 1269 1270 blk_mq_update_nr_hw_queues(&nbd->tag_set, config->num_connections); 1271 nbd->task_recv = current; 1272 1273 nbd_parse_flags(nbd); 1274 1275 error = device_create_file(disk_to_dev(nbd->disk), &pid_attr); 1276 if (error) { 1277 dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n"); 1278 return error; 1279 } 1280 set_bit(NBD_RT_HAS_PID_FILE, &config->runtime_flags); 1281 1282 nbd_dev_dbg_init(nbd); 1283 for (i = 0; i < num_connections; i++) { 1284 struct recv_thread_args *args; 1285 1286 args = kzalloc(sizeof(*args), GFP_KERNEL); 1287 if (!args) { 1288 sock_shutdown(nbd); 1289 /* 1290 * If num_connections is m (2 < m), 1291 * and NO.1 ~ NO.n(1 < n < m) kzallocs are successful. 1292 * But NO.(n + 1) failed. We still have n recv threads. 1293 * So, add flush_workqueue here to prevent recv threads 1294 * dropping the last config_refs and trying to destroy 1295 * the workqueue from inside the workqueue. 1296 */ 1297 if (i) 1298 flush_workqueue(nbd->recv_workq); 1299 return -ENOMEM; 1300 } 1301 sk_set_memalloc(config->socks[i]->sock->sk); 1302 if (nbd->tag_set.timeout) 1303 config->socks[i]->sock->sk->sk_sndtimeo = 1304 nbd->tag_set.timeout; 1305 atomic_inc(&config->recv_threads); 1306 refcount_inc(&nbd->config_refs); 1307 INIT_WORK(&args->work, recv_work); 1308 args->nbd = nbd; 1309 args->index = i; 1310 queue_work(nbd->recv_workq, &args->work); 1311 } 1312 nbd_size_update(nbd, true); 1313 return error; 1314 } 1315 1316 static int nbd_start_device_ioctl(struct nbd_device *nbd, struct block_device *bdev) 1317 { 1318 struct nbd_config *config = nbd->config; 1319 int ret; 1320 1321 ret = nbd_start_device(nbd); 1322 if (ret) 1323 return ret; 1324 1325 if (max_part) 1326 set_bit(GD_NEED_PART_SCAN, &nbd->disk->state); 1327 mutex_unlock(&nbd->config_lock); 1328 ret = wait_event_interruptible(config->recv_wq, 1329 atomic_read(&config->recv_threads) == 0); 1330 if (ret) 1331 sock_shutdown(nbd); 1332 flush_workqueue(nbd->recv_workq); 1333 1334 mutex_lock(&nbd->config_lock); 1335 nbd_bdev_reset(bdev); 1336 /* user requested, ignore socket errors */ 1337 if (test_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags)) 1338 ret = 0; 1339 if (test_bit(NBD_RT_TIMEDOUT, &config->runtime_flags)) 1340 ret = -ETIMEDOUT; 1341 return ret; 1342 } 1343 1344 static void nbd_clear_sock_ioctl(struct nbd_device *nbd, 1345 struct block_device *bdev) 1346 { 1347 sock_shutdown(nbd); 1348 __invalidate_device(bdev, true); 1349 nbd_bdev_reset(bdev); 1350 if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF, 1351 &nbd->config->runtime_flags)) 1352 nbd_config_put(nbd); 1353 } 1354 1355 static bool nbd_is_valid_blksize(unsigned long blksize) 1356 { 1357 if (!blksize || !is_power_of_2(blksize) || blksize < 512 || 1358 blksize > PAGE_SIZE) 1359 return false; 1360 return true; 1361 } 1362 1363 static void nbd_set_cmd_timeout(struct nbd_device *nbd, u64 timeout) 1364 { 1365 nbd->tag_set.timeout = timeout * HZ; 1366 if (timeout) 1367 blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ); 1368 else 1369 blk_queue_rq_timeout(nbd->disk->queue, 30 * HZ); 1370 } 1371 1372 /* Must be called with config_lock held */ 1373 static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd, 1374 unsigned int cmd, unsigned long arg) 1375 { 1376 struct nbd_config *config = nbd->config; 1377 1378 switch (cmd) { 1379 case NBD_DISCONNECT: 1380 return nbd_disconnect(nbd); 1381 case NBD_CLEAR_SOCK: 1382 nbd_clear_sock_ioctl(nbd, bdev); 1383 return 0; 1384 case NBD_SET_SOCK: 1385 return nbd_add_socket(nbd, arg, false); 1386 case NBD_SET_BLKSIZE: 1387 if (!arg) 1388 arg = NBD_DEF_BLKSIZE; 1389 if (!nbd_is_valid_blksize(arg)) 1390 return -EINVAL; 1391 nbd_size_set(nbd, arg, 1392 div_s64(config->bytesize, arg)); 1393 return 0; 1394 case NBD_SET_SIZE: 1395 nbd_size_set(nbd, config->blksize, 1396 div_s64(arg, config->blksize)); 1397 return 0; 1398 case NBD_SET_SIZE_BLOCKS: 1399 nbd_size_set(nbd, config->blksize, arg); 1400 return 0; 1401 case NBD_SET_TIMEOUT: 1402 nbd_set_cmd_timeout(nbd, arg); 1403 return 0; 1404 1405 case NBD_SET_FLAGS: 1406 config->flags = arg; 1407 return 0; 1408 case NBD_DO_IT: 1409 return nbd_start_device_ioctl(nbd, bdev); 1410 case NBD_CLEAR_QUE: 1411 /* 1412 * This is for compatibility only. The queue is always cleared 1413 * by NBD_DO_IT or NBD_CLEAR_SOCK. 1414 */ 1415 return 0; 1416 case NBD_PRINT_DEBUG: 1417 /* 1418 * For compatibility only, we no longer keep a list of 1419 * outstanding requests. 1420 */ 1421 return 0; 1422 } 1423 return -ENOTTY; 1424 } 1425 1426 static int nbd_ioctl(struct block_device *bdev, fmode_t mode, 1427 unsigned int cmd, unsigned long arg) 1428 { 1429 struct nbd_device *nbd = bdev->bd_disk->private_data; 1430 struct nbd_config *config = nbd->config; 1431 int error = -EINVAL; 1432 1433 if (!capable(CAP_SYS_ADMIN)) 1434 return -EPERM; 1435 1436 /* The block layer will pass back some non-nbd ioctls in case we have 1437 * special handling for them, but we don't so just return an error. 1438 */ 1439 if (_IOC_TYPE(cmd) != 0xab) 1440 return -EINVAL; 1441 1442 mutex_lock(&nbd->config_lock); 1443 1444 /* Don't allow ioctl operations on a nbd device that was created with 1445 * netlink, unless it's DISCONNECT or CLEAR_SOCK, which are fine. 1446 */ 1447 if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) || 1448 (cmd == NBD_DISCONNECT || cmd == NBD_CLEAR_SOCK)) 1449 error = __nbd_ioctl(bdev, nbd, cmd, arg); 1450 else 1451 dev_err(nbd_to_dev(nbd), "Cannot use ioctl interface on a netlink controlled device.\n"); 1452 mutex_unlock(&nbd->config_lock); 1453 return error; 1454 } 1455 1456 static struct nbd_config *nbd_alloc_config(void) 1457 { 1458 struct nbd_config *config; 1459 1460 config = kzalloc(sizeof(struct nbd_config), GFP_NOFS); 1461 if (!config) 1462 return NULL; 1463 atomic_set(&config->recv_threads, 0); 1464 init_waitqueue_head(&config->recv_wq); 1465 init_waitqueue_head(&config->conn_wait); 1466 config->blksize = NBD_DEF_BLKSIZE; 1467 atomic_set(&config->live_connections, 0); 1468 try_module_get(THIS_MODULE); 1469 return config; 1470 } 1471 1472 static int nbd_open(struct block_device *bdev, fmode_t mode) 1473 { 1474 struct nbd_device *nbd; 1475 int ret = 0; 1476 1477 mutex_lock(&nbd_index_mutex); 1478 nbd = bdev->bd_disk->private_data; 1479 if (!nbd) { 1480 ret = -ENXIO; 1481 goto out; 1482 } 1483 if (!refcount_inc_not_zero(&nbd->refs)) { 1484 ret = -ENXIO; 1485 goto out; 1486 } 1487 if (!refcount_inc_not_zero(&nbd->config_refs)) { 1488 struct nbd_config *config; 1489 1490 mutex_lock(&nbd->config_lock); 1491 if (refcount_inc_not_zero(&nbd->config_refs)) { 1492 mutex_unlock(&nbd->config_lock); 1493 goto out; 1494 } 1495 config = nbd->config = nbd_alloc_config(); 1496 if (!config) { 1497 ret = -ENOMEM; 1498 mutex_unlock(&nbd->config_lock); 1499 goto out; 1500 } 1501 refcount_set(&nbd->config_refs, 1); 1502 refcount_inc(&nbd->refs); 1503 mutex_unlock(&nbd->config_lock); 1504 set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state); 1505 } else if (nbd_disconnected(nbd->config)) { 1506 set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state); 1507 } 1508 out: 1509 mutex_unlock(&nbd_index_mutex); 1510 return ret; 1511 } 1512 1513 static void nbd_release(struct gendisk *disk, fmode_t mode) 1514 { 1515 struct nbd_device *nbd = disk->private_data; 1516 struct block_device *bdev = bdget_disk(disk, 0); 1517 1518 if (test_bit(NBD_RT_DISCONNECT_ON_CLOSE, &nbd->config->runtime_flags) && 1519 bdev->bd_openers == 0) 1520 nbd_disconnect_and_put(nbd); 1521 1522 nbd_config_put(nbd); 1523 nbd_put(nbd); 1524 } 1525 1526 static const struct block_device_operations nbd_fops = 1527 { 1528 .owner = THIS_MODULE, 1529 .open = nbd_open, 1530 .release = nbd_release, 1531 .ioctl = nbd_ioctl, 1532 .compat_ioctl = nbd_ioctl, 1533 }; 1534 1535 #if IS_ENABLED(CONFIG_DEBUG_FS) 1536 1537 static int nbd_dbg_tasks_show(struct seq_file *s, void *unused) 1538 { 1539 struct nbd_device *nbd = s->private; 1540 1541 if (nbd->task_recv) 1542 seq_printf(s, "recv: %d\n", task_pid_nr(nbd->task_recv)); 1543 1544 return 0; 1545 } 1546 1547 static int nbd_dbg_tasks_open(struct inode *inode, struct file *file) 1548 { 1549 return single_open(file, nbd_dbg_tasks_show, inode->i_private); 1550 } 1551 1552 static const struct file_operations nbd_dbg_tasks_ops = { 1553 .open = nbd_dbg_tasks_open, 1554 .read = seq_read, 1555 .llseek = seq_lseek, 1556 .release = single_release, 1557 }; 1558 1559 static int nbd_dbg_flags_show(struct seq_file *s, void *unused) 1560 { 1561 struct nbd_device *nbd = s->private; 1562 u32 flags = nbd->config->flags; 1563 1564 seq_printf(s, "Hex: 0x%08x\n\n", flags); 1565 1566 seq_puts(s, "Known flags:\n"); 1567 1568 if (flags & NBD_FLAG_HAS_FLAGS) 1569 seq_puts(s, "NBD_FLAG_HAS_FLAGS\n"); 1570 if (flags & NBD_FLAG_READ_ONLY) 1571 seq_puts(s, "NBD_FLAG_READ_ONLY\n"); 1572 if (flags & NBD_FLAG_SEND_FLUSH) 1573 seq_puts(s, "NBD_FLAG_SEND_FLUSH\n"); 1574 if (flags & NBD_FLAG_SEND_FUA) 1575 seq_puts(s, "NBD_FLAG_SEND_FUA\n"); 1576 if (flags & NBD_FLAG_SEND_TRIM) 1577 seq_puts(s, "NBD_FLAG_SEND_TRIM\n"); 1578 1579 return 0; 1580 } 1581 1582 static int nbd_dbg_flags_open(struct inode *inode, struct file *file) 1583 { 1584 return single_open(file, nbd_dbg_flags_show, inode->i_private); 1585 } 1586 1587 static const struct file_operations nbd_dbg_flags_ops = { 1588 .open = nbd_dbg_flags_open, 1589 .read = seq_read, 1590 .llseek = seq_lseek, 1591 .release = single_release, 1592 }; 1593 1594 static int nbd_dev_dbg_init(struct nbd_device *nbd) 1595 { 1596 struct dentry *dir; 1597 struct nbd_config *config = nbd->config; 1598 1599 if (!nbd_dbg_dir) 1600 return -EIO; 1601 1602 dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir); 1603 if (!dir) { 1604 dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s'\n", 1605 nbd_name(nbd)); 1606 return -EIO; 1607 } 1608 config->dbg_dir = dir; 1609 1610 debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_ops); 1611 debugfs_create_u64("size_bytes", 0444, dir, &config->bytesize); 1612 debugfs_create_u32("timeout", 0444, dir, &nbd->tag_set.timeout); 1613 debugfs_create_u64("blocksize", 0444, dir, &config->blksize); 1614 debugfs_create_file("flags", 0444, dir, nbd, &nbd_dbg_flags_ops); 1615 1616 return 0; 1617 } 1618 1619 static void nbd_dev_dbg_close(struct nbd_device *nbd) 1620 { 1621 debugfs_remove_recursive(nbd->config->dbg_dir); 1622 } 1623 1624 static int nbd_dbg_init(void) 1625 { 1626 struct dentry *dbg_dir; 1627 1628 dbg_dir = debugfs_create_dir("nbd", NULL); 1629 if (!dbg_dir) 1630 return -EIO; 1631 1632 nbd_dbg_dir = dbg_dir; 1633 1634 return 0; 1635 } 1636 1637 static void nbd_dbg_close(void) 1638 { 1639 debugfs_remove_recursive(nbd_dbg_dir); 1640 } 1641 1642 #else /* IS_ENABLED(CONFIG_DEBUG_FS) */ 1643 1644 static int nbd_dev_dbg_init(struct nbd_device *nbd) 1645 { 1646 return 0; 1647 } 1648 1649 static void nbd_dev_dbg_close(struct nbd_device *nbd) 1650 { 1651 } 1652 1653 static int nbd_dbg_init(void) 1654 { 1655 return 0; 1656 } 1657 1658 static void nbd_dbg_close(void) 1659 { 1660 } 1661 1662 #endif 1663 1664 static int nbd_init_request(struct blk_mq_tag_set *set, struct request *rq, 1665 unsigned int hctx_idx, unsigned int numa_node) 1666 { 1667 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq); 1668 cmd->nbd = set->driver_data; 1669 cmd->flags = 0; 1670 mutex_init(&cmd->lock); 1671 return 0; 1672 } 1673 1674 static const struct blk_mq_ops nbd_mq_ops = { 1675 .queue_rq = nbd_queue_rq, 1676 .complete = nbd_complete_rq, 1677 .init_request = nbd_init_request, 1678 .timeout = nbd_xmit_timeout, 1679 }; 1680 1681 static int nbd_dev_add(int index) 1682 { 1683 struct nbd_device *nbd; 1684 struct gendisk *disk; 1685 struct request_queue *q; 1686 int err = -ENOMEM; 1687 1688 nbd = kzalloc(sizeof(struct nbd_device), GFP_KERNEL); 1689 if (!nbd) 1690 goto out; 1691 1692 disk = alloc_disk(1 << part_shift); 1693 if (!disk) 1694 goto out_free_nbd; 1695 1696 if (index >= 0) { 1697 err = idr_alloc(&nbd_index_idr, nbd, index, index + 1, 1698 GFP_KERNEL); 1699 if (err == -ENOSPC) 1700 err = -EEXIST; 1701 } else { 1702 err = idr_alloc(&nbd_index_idr, nbd, 0, 0, GFP_KERNEL); 1703 if (err >= 0) 1704 index = err; 1705 } 1706 if (err < 0) 1707 goto out_free_disk; 1708 1709 nbd->index = index; 1710 nbd->disk = disk; 1711 nbd->tag_set.ops = &nbd_mq_ops; 1712 nbd->tag_set.nr_hw_queues = 1; 1713 nbd->tag_set.queue_depth = 128; 1714 nbd->tag_set.numa_node = NUMA_NO_NODE; 1715 nbd->tag_set.cmd_size = sizeof(struct nbd_cmd); 1716 nbd->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | 1717 BLK_MQ_F_BLOCKING; 1718 nbd->tag_set.driver_data = nbd; 1719 nbd->destroy_complete = NULL; 1720 1721 err = blk_mq_alloc_tag_set(&nbd->tag_set); 1722 if (err) 1723 goto out_free_idr; 1724 1725 q = blk_mq_init_queue(&nbd->tag_set); 1726 if (IS_ERR(q)) { 1727 err = PTR_ERR(q); 1728 goto out_free_tags; 1729 } 1730 disk->queue = q; 1731 1732 /* 1733 * Tell the block layer that we are not a rotational device 1734 */ 1735 blk_queue_flag_set(QUEUE_FLAG_NONROT, disk->queue); 1736 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, disk->queue); 1737 disk->queue->limits.discard_granularity = 0; 1738 disk->queue->limits.discard_alignment = 0; 1739 blk_queue_max_discard_sectors(disk->queue, 0); 1740 blk_queue_max_segment_size(disk->queue, UINT_MAX); 1741 blk_queue_max_segments(disk->queue, USHRT_MAX); 1742 blk_queue_max_hw_sectors(disk->queue, 65536); 1743 disk->queue->limits.max_sectors = 256; 1744 1745 mutex_init(&nbd->config_lock); 1746 refcount_set(&nbd->config_refs, 0); 1747 refcount_set(&nbd->refs, 1); 1748 INIT_LIST_HEAD(&nbd->list); 1749 disk->major = NBD_MAJOR; 1750 disk->first_minor = index << part_shift; 1751 disk->fops = &nbd_fops; 1752 disk->private_data = nbd; 1753 sprintf(disk->disk_name, "nbd%d", index); 1754 add_disk(disk); 1755 nbd_total_devices++; 1756 return index; 1757 1758 out_free_tags: 1759 blk_mq_free_tag_set(&nbd->tag_set); 1760 out_free_idr: 1761 idr_remove(&nbd_index_idr, index); 1762 out_free_disk: 1763 put_disk(disk); 1764 out_free_nbd: 1765 kfree(nbd); 1766 out: 1767 return err; 1768 } 1769 1770 static int find_free_cb(int id, void *ptr, void *data) 1771 { 1772 struct nbd_device *nbd = ptr; 1773 struct nbd_device **found = data; 1774 1775 if (!refcount_read(&nbd->config_refs)) { 1776 *found = nbd; 1777 return 1; 1778 } 1779 return 0; 1780 } 1781 1782 /* Netlink interface. */ 1783 static const struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = { 1784 [NBD_ATTR_INDEX] = { .type = NLA_U32 }, 1785 [NBD_ATTR_SIZE_BYTES] = { .type = NLA_U64 }, 1786 [NBD_ATTR_BLOCK_SIZE_BYTES] = { .type = NLA_U64 }, 1787 [NBD_ATTR_TIMEOUT] = { .type = NLA_U64 }, 1788 [NBD_ATTR_SERVER_FLAGS] = { .type = NLA_U64 }, 1789 [NBD_ATTR_CLIENT_FLAGS] = { .type = NLA_U64 }, 1790 [NBD_ATTR_SOCKETS] = { .type = NLA_NESTED}, 1791 [NBD_ATTR_DEAD_CONN_TIMEOUT] = { .type = NLA_U64 }, 1792 [NBD_ATTR_DEVICE_LIST] = { .type = NLA_NESTED}, 1793 }; 1794 1795 static const struct nla_policy nbd_sock_policy[NBD_SOCK_MAX + 1] = { 1796 [NBD_SOCK_FD] = { .type = NLA_U32 }, 1797 }; 1798 1799 /* We don't use this right now since we don't parse the incoming list, but we 1800 * still want it here so userspace knows what to expect. 1801 */ 1802 static const struct nla_policy __attribute__((unused)) 1803 nbd_device_policy[NBD_DEVICE_ATTR_MAX + 1] = { 1804 [NBD_DEVICE_INDEX] = { .type = NLA_U32 }, 1805 [NBD_DEVICE_CONNECTED] = { .type = NLA_U8 }, 1806 }; 1807 1808 static int nbd_genl_size_set(struct genl_info *info, struct nbd_device *nbd) 1809 { 1810 struct nbd_config *config = nbd->config; 1811 u64 bsize = config->blksize; 1812 u64 bytes = config->bytesize; 1813 1814 if (info->attrs[NBD_ATTR_SIZE_BYTES]) 1815 bytes = nla_get_u64(info->attrs[NBD_ATTR_SIZE_BYTES]); 1816 1817 if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]) { 1818 bsize = nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]); 1819 if (!bsize) 1820 bsize = NBD_DEF_BLKSIZE; 1821 if (!nbd_is_valid_blksize(bsize)) { 1822 printk(KERN_ERR "Invalid block size %llu\n", bsize); 1823 return -EINVAL; 1824 } 1825 } 1826 1827 if (bytes != config->bytesize || bsize != config->blksize) 1828 nbd_size_set(nbd, bsize, div64_u64(bytes, bsize)); 1829 return 0; 1830 } 1831 1832 static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info) 1833 { 1834 DECLARE_COMPLETION_ONSTACK(destroy_complete); 1835 struct nbd_device *nbd = NULL; 1836 struct nbd_config *config; 1837 int index = -1; 1838 int ret; 1839 bool put_dev = false; 1840 1841 if (!netlink_capable(skb, CAP_SYS_ADMIN)) 1842 return -EPERM; 1843 1844 if (info->attrs[NBD_ATTR_INDEX]) 1845 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]); 1846 if (!info->attrs[NBD_ATTR_SOCKETS]) { 1847 printk(KERN_ERR "nbd: must specify at least one socket\n"); 1848 return -EINVAL; 1849 } 1850 if (!info->attrs[NBD_ATTR_SIZE_BYTES]) { 1851 printk(KERN_ERR "nbd: must specify a size in bytes for the device\n"); 1852 return -EINVAL; 1853 } 1854 again: 1855 mutex_lock(&nbd_index_mutex); 1856 if (index == -1) { 1857 ret = idr_for_each(&nbd_index_idr, &find_free_cb, &nbd); 1858 if (ret == 0) { 1859 int new_index; 1860 new_index = nbd_dev_add(-1); 1861 if (new_index < 0) { 1862 mutex_unlock(&nbd_index_mutex); 1863 printk(KERN_ERR "nbd: failed to add new device\n"); 1864 return new_index; 1865 } 1866 nbd = idr_find(&nbd_index_idr, new_index); 1867 } 1868 } else { 1869 nbd = idr_find(&nbd_index_idr, index); 1870 if (!nbd) { 1871 ret = nbd_dev_add(index); 1872 if (ret < 0) { 1873 mutex_unlock(&nbd_index_mutex); 1874 printk(KERN_ERR "nbd: failed to add new device\n"); 1875 return ret; 1876 } 1877 nbd = idr_find(&nbd_index_idr, index); 1878 } 1879 } 1880 if (!nbd) { 1881 printk(KERN_ERR "nbd: couldn't find device at index %d\n", 1882 index); 1883 mutex_unlock(&nbd_index_mutex); 1884 return -EINVAL; 1885 } 1886 1887 if (test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags) && 1888 test_bit(NBD_DISCONNECT_REQUESTED, &nbd->flags)) { 1889 nbd->destroy_complete = &destroy_complete; 1890 mutex_unlock(&nbd_index_mutex); 1891 1892 /* Wait untill the the nbd stuff is totally destroyed */ 1893 wait_for_completion(&destroy_complete); 1894 goto again; 1895 } 1896 1897 if (!refcount_inc_not_zero(&nbd->refs)) { 1898 mutex_unlock(&nbd_index_mutex); 1899 if (index == -1) 1900 goto again; 1901 printk(KERN_ERR "nbd: device at index %d is going down\n", 1902 index); 1903 return -EINVAL; 1904 } 1905 mutex_unlock(&nbd_index_mutex); 1906 1907 mutex_lock(&nbd->config_lock); 1908 if (refcount_read(&nbd->config_refs)) { 1909 mutex_unlock(&nbd->config_lock); 1910 nbd_put(nbd); 1911 if (index == -1) 1912 goto again; 1913 printk(KERN_ERR "nbd: nbd%d already in use\n", index); 1914 return -EBUSY; 1915 } 1916 if (WARN_ON(nbd->config)) { 1917 mutex_unlock(&nbd->config_lock); 1918 nbd_put(nbd); 1919 return -EINVAL; 1920 } 1921 config = nbd->config = nbd_alloc_config(); 1922 if (!nbd->config) { 1923 mutex_unlock(&nbd->config_lock); 1924 nbd_put(nbd); 1925 printk(KERN_ERR "nbd: couldn't allocate config\n"); 1926 return -ENOMEM; 1927 } 1928 refcount_set(&nbd->config_refs, 1); 1929 set_bit(NBD_RT_BOUND, &config->runtime_flags); 1930 1931 ret = nbd_genl_size_set(info, nbd); 1932 if (ret) 1933 goto out; 1934 1935 if (info->attrs[NBD_ATTR_TIMEOUT]) 1936 nbd_set_cmd_timeout(nbd, 1937 nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT])); 1938 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) { 1939 config->dead_conn_timeout = 1940 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]); 1941 config->dead_conn_timeout *= HZ; 1942 } 1943 if (info->attrs[NBD_ATTR_SERVER_FLAGS]) 1944 config->flags = 1945 nla_get_u64(info->attrs[NBD_ATTR_SERVER_FLAGS]); 1946 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) { 1947 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]); 1948 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) { 1949 set_bit(NBD_RT_DESTROY_ON_DISCONNECT, 1950 &config->runtime_flags); 1951 set_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags); 1952 put_dev = true; 1953 } else { 1954 clear_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags); 1955 } 1956 if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) { 1957 set_bit(NBD_RT_DISCONNECT_ON_CLOSE, 1958 &config->runtime_flags); 1959 } 1960 } 1961 1962 if (info->attrs[NBD_ATTR_SOCKETS]) { 1963 struct nlattr *attr; 1964 int rem, fd; 1965 1966 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS], 1967 rem) { 1968 struct nlattr *socks[NBD_SOCK_MAX+1]; 1969 1970 if (nla_type(attr) != NBD_SOCK_ITEM) { 1971 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n"); 1972 ret = -EINVAL; 1973 goto out; 1974 } 1975 ret = nla_parse_nested_deprecated(socks, NBD_SOCK_MAX, 1976 attr, 1977 nbd_sock_policy, 1978 info->extack); 1979 if (ret != 0) { 1980 printk(KERN_ERR "nbd: error processing sock list\n"); 1981 ret = -EINVAL; 1982 goto out; 1983 } 1984 if (!socks[NBD_SOCK_FD]) 1985 continue; 1986 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]); 1987 ret = nbd_add_socket(nbd, fd, true); 1988 if (ret) 1989 goto out; 1990 } 1991 } 1992 ret = nbd_start_device(nbd); 1993 out: 1994 mutex_unlock(&nbd->config_lock); 1995 if (!ret) { 1996 set_bit(NBD_RT_HAS_CONFIG_REF, &config->runtime_flags); 1997 refcount_inc(&nbd->config_refs); 1998 nbd_connect_reply(info, nbd->index); 1999 } 2000 nbd_config_put(nbd); 2001 if (put_dev) 2002 nbd_put(nbd); 2003 return ret; 2004 } 2005 2006 static void nbd_disconnect_and_put(struct nbd_device *nbd) 2007 { 2008 mutex_lock(&nbd->config_lock); 2009 nbd_disconnect(nbd); 2010 nbd_clear_sock(nbd); 2011 mutex_unlock(&nbd->config_lock); 2012 /* 2013 * Make sure recv thread has finished, so it does not drop the last 2014 * config ref and try to destroy the workqueue from inside the work 2015 * queue. 2016 */ 2017 flush_workqueue(nbd->recv_workq); 2018 if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF, 2019 &nbd->config->runtime_flags)) 2020 nbd_config_put(nbd); 2021 } 2022 2023 static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info) 2024 { 2025 struct nbd_device *nbd; 2026 int index; 2027 2028 if (!netlink_capable(skb, CAP_SYS_ADMIN)) 2029 return -EPERM; 2030 2031 if (!info->attrs[NBD_ATTR_INDEX]) { 2032 printk(KERN_ERR "nbd: must specify an index to disconnect\n"); 2033 return -EINVAL; 2034 } 2035 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]); 2036 mutex_lock(&nbd_index_mutex); 2037 nbd = idr_find(&nbd_index_idr, index); 2038 if (!nbd) { 2039 mutex_unlock(&nbd_index_mutex); 2040 printk(KERN_ERR "nbd: couldn't find device at index %d\n", 2041 index); 2042 return -EINVAL; 2043 } 2044 if (!refcount_inc_not_zero(&nbd->refs)) { 2045 mutex_unlock(&nbd_index_mutex); 2046 printk(KERN_ERR "nbd: device at index %d is going down\n", 2047 index); 2048 return -EINVAL; 2049 } 2050 mutex_unlock(&nbd_index_mutex); 2051 if (!refcount_inc_not_zero(&nbd->config_refs)) { 2052 nbd_put(nbd); 2053 return 0; 2054 } 2055 nbd_disconnect_and_put(nbd); 2056 nbd_config_put(nbd); 2057 nbd_put(nbd); 2058 return 0; 2059 } 2060 2061 static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info) 2062 { 2063 struct nbd_device *nbd = NULL; 2064 struct nbd_config *config; 2065 int index; 2066 int ret = 0; 2067 bool put_dev = false; 2068 2069 if (!netlink_capable(skb, CAP_SYS_ADMIN)) 2070 return -EPERM; 2071 2072 if (!info->attrs[NBD_ATTR_INDEX]) { 2073 printk(KERN_ERR "nbd: must specify a device to reconfigure\n"); 2074 return -EINVAL; 2075 } 2076 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]); 2077 mutex_lock(&nbd_index_mutex); 2078 nbd = idr_find(&nbd_index_idr, index); 2079 if (!nbd) { 2080 mutex_unlock(&nbd_index_mutex); 2081 printk(KERN_ERR "nbd: couldn't find a device at index %d\n", 2082 index); 2083 return -EINVAL; 2084 } 2085 if (!refcount_inc_not_zero(&nbd->refs)) { 2086 mutex_unlock(&nbd_index_mutex); 2087 printk(KERN_ERR "nbd: device at index %d is going down\n", 2088 index); 2089 return -EINVAL; 2090 } 2091 mutex_unlock(&nbd_index_mutex); 2092 2093 if (!refcount_inc_not_zero(&nbd->config_refs)) { 2094 dev_err(nbd_to_dev(nbd), 2095 "not configured, cannot reconfigure\n"); 2096 nbd_put(nbd); 2097 return -EINVAL; 2098 } 2099 2100 mutex_lock(&nbd->config_lock); 2101 config = nbd->config; 2102 if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) || 2103 !nbd->task_recv) { 2104 dev_err(nbd_to_dev(nbd), 2105 "not configured, cannot reconfigure\n"); 2106 ret = -EINVAL; 2107 goto out; 2108 } 2109 2110 ret = nbd_genl_size_set(info, nbd); 2111 if (ret) 2112 goto out; 2113 2114 if (info->attrs[NBD_ATTR_TIMEOUT]) 2115 nbd_set_cmd_timeout(nbd, 2116 nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT])); 2117 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) { 2118 config->dead_conn_timeout = 2119 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]); 2120 config->dead_conn_timeout *= HZ; 2121 } 2122 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) { 2123 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]); 2124 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) { 2125 if (!test_and_set_bit(NBD_RT_DESTROY_ON_DISCONNECT, 2126 &config->runtime_flags)) 2127 put_dev = true; 2128 set_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags); 2129 } else { 2130 if (test_and_clear_bit(NBD_RT_DESTROY_ON_DISCONNECT, 2131 &config->runtime_flags)) 2132 refcount_inc(&nbd->refs); 2133 clear_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags); 2134 } 2135 2136 if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) { 2137 set_bit(NBD_RT_DISCONNECT_ON_CLOSE, 2138 &config->runtime_flags); 2139 } else { 2140 clear_bit(NBD_RT_DISCONNECT_ON_CLOSE, 2141 &config->runtime_flags); 2142 } 2143 } 2144 2145 if (info->attrs[NBD_ATTR_SOCKETS]) { 2146 struct nlattr *attr; 2147 int rem, fd; 2148 2149 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS], 2150 rem) { 2151 struct nlattr *socks[NBD_SOCK_MAX+1]; 2152 2153 if (nla_type(attr) != NBD_SOCK_ITEM) { 2154 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n"); 2155 ret = -EINVAL; 2156 goto out; 2157 } 2158 ret = nla_parse_nested_deprecated(socks, NBD_SOCK_MAX, 2159 attr, 2160 nbd_sock_policy, 2161 info->extack); 2162 if (ret != 0) { 2163 printk(KERN_ERR "nbd: error processing sock list\n"); 2164 ret = -EINVAL; 2165 goto out; 2166 } 2167 if (!socks[NBD_SOCK_FD]) 2168 continue; 2169 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]); 2170 ret = nbd_reconnect_socket(nbd, fd); 2171 if (ret) { 2172 if (ret == -ENOSPC) 2173 ret = 0; 2174 goto out; 2175 } 2176 dev_info(nbd_to_dev(nbd), "reconnected socket\n"); 2177 } 2178 } 2179 out: 2180 mutex_unlock(&nbd->config_lock); 2181 nbd_config_put(nbd); 2182 nbd_put(nbd); 2183 if (put_dev) 2184 nbd_put(nbd); 2185 return ret; 2186 } 2187 2188 static const struct genl_small_ops nbd_connect_genl_ops[] = { 2189 { 2190 .cmd = NBD_CMD_CONNECT, 2191 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 2192 .doit = nbd_genl_connect, 2193 }, 2194 { 2195 .cmd = NBD_CMD_DISCONNECT, 2196 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 2197 .doit = nbd_genl_disconnect, 2198 }, 2199 { 2200 .cmd = NBD_CMD_RECONFIGURE, 2201 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 2202 .doit = nbd_genl_reconfigure, 2203 }, 2204 { 2205 .cmd = NBD_CMD_STATUS, 2206 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP, 2207 .doit = nbd_genl_status, 2208 }, 2209 }; 2210 2211 static const struct genl_multicast_group nbd_mcast_grps[] = { 2212 { .name = NBD_GENL_MCAST_GROUP_NAME, }, 2213 }; 2214 2215 static struct genl_family nbd_genl_family __ro_after_init = { 2216 .hdrsize = 0, 2217 .name = NBD_GENL_FAMILY_NAME, 2218 .version = NBD_GENL_VERSION, 2219 .module = THIS_MODULE, 2220 .small_ops = nbd_connect_genl_ops, 2221 .n_small_ops = ARRAY_SIZE(nbd_connect_genl_ops), 2222 .maxattr = NBD_ATTR_MAX, 2223 .policy = nbd_attr_policy, 2224 .mcgrps = nbd_mcast_grps, 2225 .n_mcgrps = ARRAY_SIZE(nbd_mcast_grps), 2226 }; 2227 2228 static int populate_nbd_status(struct nbd_device *nbd, struct sk_buff *reply) 2229 { 2230 struct nlattr *dev_opt; 2231 u8 connected = 0; 2232 int ret; 2233 2234 /* This is a little racey, but for status it's ok. The 2235 * reason we don't take a ref here is because we can't 2236 * take a ref in the index == -1 case as we would need 2237 * to put under the nbd_index_mutex, which could 2238 * deadlock if we are configured to remove ourselves 2239 * once we're disconnected. 2240 */ 2241 if (refcount_read(&nbd->config_refs)) 2242 connected = 1; 2243 dev_opt = nla_nest_start_noflag(reply, NBD_DEVICE_ITEM); 2244 if (!dev_opt) 2245 return -EMSGSIZE; 2246 ret = nla_put_u32(reply, NBD_DEVICE_INDEX, nbd->index); 2247 if (ret) 2248 return -EMSGSIZE; 2249 ret = nla_put_u8(reply, NBD_DEVICE_CONNECTED, 2250 connected); 2251 if (ret) 2252 return -EMSGSIZE; 2253 nla_nest_end(reply, dev_opt); 2254 return 0; 2255 } 2256 2257 static int status_cb(int id, void *ptr, void *data) 2258 { 2259 struct nbd_device *nbd = ptr; 2260 return populate_nbd_status(nbd, (struct sk_buff *)data); 2261 } 2262 2263 static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info) 2264 { 2265 struct nlattr *dev_list; 2266 struct sk_buff *reply; 2267 void *reply_head; 2268 size_t msg_size; 2269 int index = -1; 2270 int ret = -ENOMEM; 2271 2272 if (info->attrs[NBD_ATTR_INDEX]) 2273 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]); 2274 2275 mutex_lock(&nbd_index_mutex); 2276 2277 msg_size = nla_total_size(nla_attr_size(sizeof(u32)) + 2278 nla_attr_size(sizeof(u8))); 2279 msg_size *= (index == -1) ? nbd_total_devices : 1; 2280 2281 reply = genlmsg_new(msg_size, GFP_KERNEL); 2282 if (!reply) 2283 goto out; 2284 reply_head = genlmsg_put_reply(reply, info, &nbd_genl_family, 0, 2285 NBD_CMD_STATUS); 2286 if (!reply_head) { 2287 nlmsg_free(reply); 2288 goto out; 2289 } 2290 2291 dev_list = nla_nest_start_noflag(reply, NBD_ATTR_DEVICE_LIST); 2292 if (index == -1) { 2293 ret = idr_for_each(&nbd_index_idr, &status_cb, reply); 2294 if (ret) { 2295 nlmsg_free(reply); 2296 goto out; 2297 } 2298 } else { 2299 struct nbd_device *nbd; 2300 nbd = idr_find(&nbd_index_idr, index); 2301 if (nbd) { 2302 ret = populate_nbd_status(nbd, reply); 2303 if (ret) { 2304 nlmsg_free(reply); 2305 goto out; 2306 } 2307 } 2308 } 2309 nla_nest_end(reply, dev_list); 2310 genlmsg_end(reply, reply_head); 2311 ret = genlmsg_reply(reply, info); 2312 out: 2313 mutex_unlock(&nbd_index_mutex); 2314 return ret; 2315 } 2316 2317 static void nbd_connect_reply(struct genl_info *info, int index) 2318 { 2319 struct sk_buff *skb; 2320 void *msg_head; 2321 int ret; 2322 2323 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL); 2324 if (!skb) 2325 return; 2326 msg_head = genlmsg_put_reply(skb, info, &nbd_genl_family, 0, 2327 NBD_CMD_CONNECT); 2328 if (!msg_head) { 2329 nlmsg_free(skb); 2330 return; 2331 } 2332 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index); 2333 if (ret) { 2334 nlmsg_free(skb); 2335 return; 2336 } 2337 genlmsg_end(skb, msg_head); 2338 genlmsg_reply(skb, info); 2339 } 2340 2341 static void nbd_mcast_index(int index) 2342 { 2343 struct sk_buff *skb; 2344 void *msg_head; 2345 int ret; 2346 2347 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL); 2348 if (!skb) 2349 return; 2350 msg_head = genlmsg_put(skb, 0, 0, &nbd_genl_family, 0, 2351 NBD_CMD_LINK_DEAD); 2352 if (!msg_head) { 2353 nlmsg_free(skb); 2354 return; 2355 } 2356 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index); 2357 if (ret) { 2358 nlmsg_free(skb); 2359 return; 2360 } 2361 genlmsg_end(skb, msg_head); 2362 genlmsg_multicast(&nbd_genl_family, skb, 0, 0, GFP_KERNEL); 2363 } 2364 2365 static void nbd_dead_link_work(struct work_struct *work) 2366 { 2367 struct link_dead_args *args = container_of(work, struct link_dead_args, 2368 work); 2369 nbd_mcast_index(args->index); 2370 kfree(args); 2371 } 2372 2373 static int __init nbd_init(void) 2374 { 2375 int i; 2376 2377 BUILD_BUG_ON(sizeof(struct nbd_request) != 28); 2378 2379 if (max_part < 0) { 2380 printk(KERN_ERR "nbd: max_part must be >= 0\n"); 2381 return -EINVAL; 2382 } 2383 2384 part_shift = 0; 2385 if (max_part > 0) { 2386 part_shift = fls(max_part); 2387 2388 /* 2389 * Adjust max_part according to part_shift as it is exported 2390 * to user space so that user can know the max number of 2391 * partition kernel should be able to manage. 2392 * 2393 * Note that -1 is required because partition 0 is reserved 2394 * for the whole disk. 2395 */ 2396 max_part = (1UL << part_shift) - 1; 2397 } 2398 2399 if ((1UL << part_shift) > DISK_MAX_PARTS) 2400 return -EINVAL; 2401 2402 if (nbds_max > 1UL << (MINORBITS - part_shift)) 2403 return -EINVAL; 2404 2405 if (register_blkdev(NBD_MAJOR, "nbd")) 2406 return -EIO; 2407 2408 if (genl_register_family(&nbd_genl_family)) { 2409 unregister_blkdev(NBD_MAJOR, "nbd"); 2410 return -EINVAL; 2411 } 2412 nbd_dbg_init(); 2413 2414 mutex_lock(&nbd_index_mutex); 2415 for (i = 0; i < nbds_max; i++) 2416 nbd_dev_add(i); 2417 mutex_unlock(&nbd_index_mutex); 2418 return 0; 2419 } 2420 2421 static int nbd_exit_cb(int id, void *ptr, void *data) 2422 { 2423 struct list_head *list = (struct list_head *)data; 2424 struct nbd_device *nbd = ptr; 2425 2426 list_add_tail(&nbd->list, list); 2427 return 0; 2428 } 2429 2430 static void __exit nbd_cleanup(void) 2431 { 2432 struct nbd_device *nbd; 2433 LIST_HEAD(del_list); 2434 2435 nbd_dbg_close(); 2436 2437 mutex_lock(&nbd_index_mutex); 2438 idr_for_each(&nbd_index_idr, &nbd_exit_cb, &del_list); 2439 mutex_unlock(&nbd_index_mutex); 2440 2441 while (!list_empty(&del_list)) { 2442 nbd = list_first_entry(&del_list, struct nbd_device, list); 2443 list_del_init(&nbd->list); 2444 if (refcount_read(&nbd->refs) != 1) 2445 printk(KERN_ERR "nbd: possibly leaking a device\n"); 2446 nbd_put(nbd); 2447 } 2448 2449 idr_destroy(&nbd_index_idr); 2450 genl_unregister_family(&nbd_genl_family); 2451 unregister_blkdev(NBD_MAJOR, "nbd"); 2452 } 2453 2454 module_init(nbd_init); 2455 module_exit(nbd_cleanup); 2456 2457 MODULE_DESCRIPTION("Network Block Device"); 2458 MODULE_LICENSE("GPL"); 2459 2460 module_param(nbds_max, int, 0444); 2461 MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)"); 2462 module_param(max_part, int, 0444); 2463 MODULE_PARM_DESC(max_part, "number of partitions per device (default: 16)"); 2464