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