1 /* 2 * Network block device - make block devices work over TCP 3 * 4 * Note that you can not swap over this thing, yet. Seems to work but 5 * deadlocks sometimes - you can not swap over TCP in general. 6 * 7 * Copyright 1997-2000, 2008 Pavel Machek <pavel@ucw.cz> 8 * Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com> 9 * 10 * This file is released under GPLv2 or later. 11 * 12 * (part of code stolen from loop.c) 13 */ 14 15 #include <linux/major.h> 16 17 #include <linux/blkdev.h> 18 #include <linux/module.h> 19 #include <linux/init.h> 20 #include <linux/sched.h> 21 #include <linux/sched/mm.h> 22 #include <linux/fs.h> 23 #include <linux/bio.h> 24 #include <linux/stat.h> 25 #include <linux/errno.h> 26 #include <linux/file.h> 27 #include <linux/ioctl.h> 28 #include <linux/mutex.h> 29 #include <linux/compiler.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 static DEFINE_IDR(nbd_index_idr); 48 static DEFINE_MUTEX(nbd_index_mutex); 49 static int nbd_total_devices = 0; 50 51 struct nbd_sock { 52 struct socket *sock; 53 struct mutex tx_lock; 54 struct request *pending; 55 int sent; 56 bool dead; 57 int fallback_index; 58 int cookie; 59 }; 60 61 struct recv_thread_args { 62 struct work_struct work; 63 struct nbd_device *nbd; 64 int index; 65 }; 66 67 struct link_dead_args { 68 struct work_struct work; 69 int index; 70 }; 71 72 #define NBD_TIMEDOUT 0 73 #define NBD_DISCONNECT_REQUESTED 1 74 #define NBD_DISCONNECTED 2 75 #define NBD_HAS_PID_FILE 3 76 #define NBD_HAS_CONFIG_REF 4 77 #define NBD_BOUND 5 78 #define NBD_DESTROY_ON_DISCONNECT 6 79 80 struct nbd_config { 81 u32 flags; 82 unsigned long runtime_flags; 83 u64 dead_conn_timeout; 84 85 struct nbd_sock **socks; 86 int num_connections; 87 atomic_t live_connections; 88 wait_queue_head_t conn_wait; 89 90 atomic_t recv_threads; 91 wait_queue_head_t recv_wq; 92 loff_t blksize; 93 loff_t bytesize; 94 #if IS_ENABLED(CONFIG_DEBUG_FS) 95 struct dentry *dbg_dir; 96 #endif 97 }; 98 99 struct nbd_device { 100 struct blk_mq_tag_set tag_set; 101 102 int index; 103 refcount_t config_refs; 104 refcount_t refs; 105 struct nbd_config *config; 106 struct mutex config_lock; 107 struct gendisk *disk; 108 109 struct list_head list; 110 struct task_struct *task_recv; 111 struct task_struct *task_setup; 112 }; 113 114 struct nbd_cmd { 115 struct nbd_device *nbd; 116 int index; 117 int cookie; 118 struct completion send_complete; 119 blk_status_t status; 120 }; 121 122 #if IS_ENABLED(CONFIG_DEBUG_FS) 123 static struct dentry *nbd_dbg_dir; 124 #endif 125 126 #define nbd_name(nbd) ((nbd)->disk->disk_name) 127 128 #define NBD_MAGIC 0x68797548 129 130 static unsigned int nbds_max = 16; 131 static int max_part = 16; 132 static struct workqueue_struct *recv_workqueue; 133 static int part_shift; 134 135 static int nbd_dev_dbg_init(struct nbd_device *nbd); 136 static void nbd_dev_dbg_close(struct nbd_device *nbd); 137 static void nbd_config_put(struct nbd_device *nbd); 138 static void nbd_connect_reply(struct genl_info *info, int index); 139 static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info); 140 static void nbd_dead_link_work(struct work_struct *work); 141 142 static inline struct device *nbd_to_dev(struct nbd_device *nbd) 143 { 144 return disk_to_dev(nbd->disk); 145 } 146 147 static const char *nbdcmd_to_ascii(int cmd) 148 { 149 switch (cmd) { 150 case NBD_CMD_READ: return "read"; 151 case NBD_CMD_WRITE: return "write"; 152 case NBD_CMD_DISC: return "disconnect"; 153 case NBD_CMD_FLUSH: return "flush"; 154 case NBD_CMD_TRIM: return "trim/discard"; 155 } 156 return "invalid"; 157 } 158 159 static ssize_t pid_show(struct device *dev, 160 struct device_attribute *attr, char *buf) 161 { 162 struct gendisk *disk = dev_to_disk(dev); 163 struct nbd_device *nbd = (struct nbd_device *)disk->private_data; 164 165 return sprintf(buf, "%d\n", task_pid_nr(nbd->task_recv)); 166 } 167 168 static const struct device_attribute pid_attr = { 169 .attr = { .name = "pid", .mode = S_IRUGO}, 170 .show = pid_show, 171 }; 172 173 static void nbd_dev_remove(struct nbd_device *nbd) 174 { 175 struct gendisk *disk = nbd->disk; 176 if (disk) { 177 del_gendisk(disk); 178 blk_cleanup_queue(disk->queue); 179 blk_mq_free_tag_set(&nbd->tag_set); 180 disk->private_data = NULL; 181 put_disk(disk); 182 } 183 kfree(nbd); 184 } 185 186 static void nbd_put(struct nbd_device *nbd) 187 { 188 if (refcount_dec_and_mutex_lock(&nbd->refs, 189 &nbd_index_mutex)) { 190 idr_remove(&nbd_index_idr, nbd->index); 191 mutex_unlock(&nbd_index_mutex); 192 nbd_dev_remove(nbd); 193 } 194 } 195 196 static int nbd_disconnected(struct nbd_config *config) 197 { 198 return test_bit(NBD_DISCONNECTED, &config->runtime_flags) || 199 test_bit(NBD_DISCONNECT_REQUESTED, &config->runtime_flags); 200 } 201 202 static void nbd_mark_nsock_dead(struct nbd_device *nbd, struct nbd_sock *nsock, 203 int notify) 204 { 205 if (!nsock->dead && notify && !nbd_disconnected(nbd->config)) { 206 struct link_dead_args *args; 207 args = kmalloc(sizeof(struct link_dead_args), GFP_NOIO); 208 if (args) { 209 INIT_WORK(&args->work, nbd_dead_link_work); 210 args->index = nbd->index; 211 queue_work(system_wq, &args->work); 212 } 213 } 214 if (!nsock->dead) { 215 kernel_sock_shutdown(nsock->sock, SHUT_RDWR); 216 atomic_dec(&nbd->config->live_connections); 217 } 218 nsock->dead = true; 219 nsock->pending = NULL; 220 nsock->sent = 0; 221 } 222 223 static void nbd_size_clear(struct nbd_device *nbd) 224 { 225 if (nbd->config->bytesize) { 226 set_capacity(nbd->disk, 0); 227 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE); 228 } 229 } 230 231 static void nbd_size_update(struct nbd_device *nbd) 232 { 233 struct nbd_config *config = nbd->config; 234 blk_queue_logical_block_size(nbd->disk->queue, config->blksize); 235 blk_queue_physical_block_size(nbd->disk->queue, config->blksize); 236 set_capacity(nbd->disk, config->bytesize >> 9); 237 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE); 238 } 239 240 static void nbd_size_set(struct nbd_device *nbd, loff_t blocksize, 241 loff_t nr_blocks) 242 { 243 struct nbd_config *config = nbd->config; 244 config->blksize = blocksize; 245 config->bytesize = blocksize * nr_blocks; 246 } 247 248 static void nbd_complete_rq(struct request *req) 249 { 250 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req); 251 252 dev_dbg(nbd_to_dev(cmd->nbd), "request %p: %s\n", cmd, 253 cmd->status ? "failed" : "done"); 254 255 blk_mq_end_request(req, cmd->status); 256 } 257 258 /* 259 * Forcibly shutdown the socket causing all listeners to error 260 */ 261 static void sock_shutdown(struct nbd_device *nbd) 262 { 263 struct nbd_config *config = nbd->config; 264 int i; 265 266 if (config->num_connections == 0) 267 return; 268 if (test_and_set_bit(NBD_DISCONNECTED, &config->runtime_flags)) 269 return; 270 271 for (i = 0; i < config->num_connections; i++) { 272 struct nbd_sock *nsock = config->socks[i]; 273 mutex_lock(&nsock->tx_lock); 274 nbd_mark_nsock_dead(nbd, nsock, 0); 275 mutex_unlock(&nsock->tx_lock); 276 } 277 dev_warn(disk_to_dev(nbd->disk), "shutting down sockets\n"); 278 } 279 280 static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req, 281 bool reserved) 282 { 283 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req); 284 struct nbd_device *nbd = cmd->nbd; 285 struct nbd_config *config; 286 287 if (!refcount_inc_not_zero(&nbd->config_refs)) { 288 cmd->status = BLK_STS_TIMEOUT; 289 return BLK_EH_HANDLED; 290 } 291 config = nbd->config; 292 293 if (config->num_connections > 1) { 294 dev_err_ratelimited(nbd_to_dev(nbd), 295 "Connection timed out, retrying\n"); 296 /* 297 * Hooray we have more connections, requeue this IO, the submit 298 * path will put it on a real connection. 299 */ 300 if (config->socks && config->num_connections > 1) { 301 if (cmd->index < config->num_connections) { 302 struct nbd_sock *nsock = 303 config->socks[cmd->index]; 304 mutex_lock(&nsock->tx_lock); 305 /* We can have multiple outstanding requests, so 306 * we don't want to mark the nsock dead if we've 307 * already reconnected with a new socket, so 308 * only mark it dead if its the same socket we 309 * were sent out on. 310 */ 311 if (cmd->cookie == nsock->cookie) 312 nbd_mark_nsock_dead(nbd, nsock, 1); 313 mutex_unlock(&nsock->tx_lock); 314 } 315 blk_mq_requeue_request(req, true); 316 nbd_config_put(nbd); 317 return BLK_EH_NOT_HANDLED; 318 } 319 } else { 320 dev_err_ratelimited(nbd_to_dev(nbd), 321 "Connection timed out\n"); 322 } 323 set_bit(NBD_TIMEDOUT, &config->runtime_flags); 324 cmd->status = BLK_STS_IOERR; 325 sock_shutdown(nbd); 326 nbd_config_put(nbd); 327 328 return BLK_EH_HANDLED; 329 } 330 331 /* 332 * Send or receive packet. 333 */ 334 static int sock_xmit(struct nbd_device *nbd, int index, int send, 335 struct iov_iter *iter, int msg_flags, int *sent) 336 { 337 struct nbd_config *config = nbd->config; 338 struct socket *sock = config->socks[index]->sock; 339 int result; 340 struct msghdr msg; 341 unsigned int noreclaim_flag; 342 343 if (unlikely(!sock)) { 344 dev_err_ratelimited(disk_to_dev(nbd->disk), 345 "Attempted %s on closed socket in sock_xmit\n", 346 (send ? "send" : "recv")); 347 return -EINVAL; 348 } 349 350 msg.msg_iter = *iter; 351 352 noreclaim_flag = memalloc_noreclaim_save(); 353 do { 354 sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC; 355 msg.msg_name = NULL; 356 msg.msg_namelen = 0; 357 msg.msg_control = NULL; 358 msg.msg_controllen = 0; 359 msg.msg_flags = msg_flags | MSG_NOSIGNAL; 360 361 if (send) 362 result = sock_sendmsg(sock, &msg); 363 else 364 result = sock_recvmsg(sock, &msg, msg.msg_flags); 365 366 if (result <= 0) { 367 if (result == 0) 368 result = -EPIPE; /* short read */ 369 break; 370 } 371 if (sent) 372 *sent += result; 373 } while (msg_data_left(&msg)); 374 375 memalloc_noreclaim_restore(noreclaim_flag); 376 377 return result; 378 } 379 380 /* 381 * Different settings for sk->sk_sndtimeo can result in different return values 382 * if there is a signal pending when we enter sendmsg, because reasons? 383 */ 384 static inline int was_interrupted(int result) 385 { 386 return result == -ERESTARTSYS || result == -EINTR; 387 } 388 389 /* always call with the tx_lock held */ 390 static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index) 391 { 392 struct request *req = blk_mq_rq_from_pdu(cmd); 393 struct nbd_config *config = nbd->config; 394 struct nbd_sock *nsock = config->socks[index]; 395 int result; 396 struct nbd_request request = {.magic = htonl(NBD_REQUEST_MAGIC)}; 397 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)}; 398 struct iov_iter from; 399 unsigned long size = blk_rq_bytes(req); 400 struct bio *bio; 401 u32 type; 402 u32 nbd_cmd_flags = 0; 403 u32 tag = blk_mq_unique_tag(req); 404 int sent = nsock->sent, skip = 0; 405 406 iov_iter_kvec(&from, WRITE | ITER_KVEC, &iov, 1, sizeof(request)); 407 408 switch (req_op(req)) { 409 case REQ_OP_DISCARD: 410 type = NBD_CMD_TRIM; 411 break; 412 case REQ_OP_FLUSH: 413 type = NBD_CMD_FLUSH; 414 break; 415 case REQ_OP_WRITE: 416 type = NBD_CMD_WRITE; 417 break; 418 case REQ_OP_READ: 419 type = NBD_CMD_READ; 420 break; 421 default: 422 return -EIO; 423 } 424 425 if (rq_data_dir(req) == WRITE && 426 (config->flags & NBD_FLAG_READ_ONLY)) { 427 dev_err_ratelimited(disk_to_dev(nbd->disk), 428 "Write on read-only\n"); 429 return -EIO; 430 } 431 432 if (req->cmd_flags & REQ_FUA) 433 nbd_cmd_flags |= NBD_CMD_FLAG_FUA; 434 435 /* We did a partial send previously, and we at least sent the whole 436 * request struct, so just go and send the rest of the pages in the 437 * request. 438 */ 439 if (sent) { 440 if (sent >= sizeof(request)) { 441 skip = sent - sizeof(request); 442 goto send_pages; 443 } 444 iov_iter_advance(&from, sent); 445 } 446 cmd->index = index; 447 cmd->cookie = nsock->cookie; 448 request.type = htonl(type | nbd_cmd_flags); 449 if (type != NBD_CMD_FLUSH) { 450 request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9); 451 request.len = htonl(size); 452 } 453 memcpy(request.handle, &tag, sizeof(tag)); 454 455 dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n", 456 cmd, nbdcmd_to_ascii(type), 457 (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req)); 458 result = sock_xmit(nbd, index, 1, &from, 459 (type == NBD_CMD_WRITE) ? MSG_MORE : 0, &sent); 460 if (result <= 0) { 461 if (was_interrupted(result)) { 462 /* If we havne't sent anything we can just return BUSY, 463 * however if we have sent something we need to make 464 * sure we only allow this req to be sent until we are 465 * completely done. 466 */ 467 if (sent) { 468 nsock->pending = req; 469 nsock->sent = sent; 470 } 471 return BLK_STS_RESOURCE; 472 } 473 dev_err_ratelimited(disk_to_dev(nbd->disk), 474 "Send control failed (result %d)\n", result); 475 return -EAGAIN; 476 } 477 send_pages: 478 if (type != NBD_CMD_WRITE) 479 goto out; 480 481 bio = req->bio; 482 while (bio) { 483 struct bio *next = bio->bi_next; 484 struct bvec_iter iter; 485 struct bio_vec bvec; 486 487 bio_for_each_segment(bvec, bio, iter) { 488 bool is_last = !next && bio_iter_last(bvec, iter); 489 int flags = is_last ? 0 : MSG_MORE; 490 491 dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n", 492 cmd, bvec.bv_len); 493 iov_iter_bvec(&from, ITER_BVEC | WRITE, 494 &bvec, 1, bvec.bv_len); 495 if (skip) { 496 if (skip >= iov_iter_count(&from)) { 497 skip -= iov_iter_count(&from); 498 continue; 499 } 500 iov_iter_advance(&from, skip); 501 skip = 0; 502 } 503 result = sock_xmit(nbd, index, 1, &from, flags, &sent); 504 if (result <= 0) { 505 if (was_interrupted(result)) { 506 /* We've already sent the header, we 507 * have no choice but to set pending and 508 * return BUSY. 509 */ 510 nsock->pending = req; 511 nsock->sent = sent; 512 return BLK_STS_RESOURCE; 513 } 514 dev_err(disk_to_dev(nbd->disk), 515 "Send data failed (result %d)\n", 516 result); 517 return -EAGAIN; 518 } 519 /* 520 * The completion might already have come in, 521 * so break for the last one instead of letting 522 * the iterator do it. This prevents use-after-free 523 * of the bio. 524 */ 525 if (is_last) 526 break; 527 } 528 bio = next; 529 } 530 out: 531 nsock->pending = NULL; 532 nsock->sent = 0; 533 return 0; 534 } 535 536 /* NULL returned = something went wrong, inform userspace */ 537 static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index) 538 { 539 struct nbd_config *config = nbd->config; 540 int result; 541 struct nbd_reply reply; 542 struct nbd_cmd *cmd; 543 struct request *req = NULL; 544 u16 hwq; 545 u32 tag; 546 struct kvec iov = {.iov_base = &reply, .iov_len = sizeof(reply)}; 547 struct iov_iter to; 548 549 reply.magic = 0; 550 iov_iter_kvec(&to, READ | ITER_KVEC, &iov, 1, sizeof(reply)); 551 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL); 552 if (result <= 0) { 553 if (!nbd_disconnected(config)) 554 dev_err(disk_to_dev(nbd->disk), 555 "Receive control failed (result %d)\n", result); 556 return ERR_PTR(result); 557 } 558 559 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) { 560 dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n", 561 (unsigned long)ntohl(reply.magic)); 562 return ERR_PTR(-EPROTO); 563 } 564 565 memcpy(&tag, reply.handle, sizeof(u32)); 566 567 hwq = blk_mq_unique_tag_to_hwq(tag); 568 if (hwq < nbd->tag_set.nr_hw_queues) 569 req = blk_mq_tag_to_rq(nbd->tag_set.tags[hwq], 570 blk_mq_unique_tag_to_tag(tag)); 571 if (!req || !blk_mq_request_started(req)) { 572 dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%d) %p\n", 573 tag, req); 574 return ERR_PTR(-ENOENT); 575 } 576 cmd = blk_mq_rq_to_pdu(req); 577 if (ntohl(reply.error)) { 578 dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n", 579 ntohl(reply.error)); 580 cmd->status = BLK_STS_IOERR; 581 return cmd; 582 } 583 584 dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", cmd); 585 if (rq_data_dir(req) != WRITE) { 586 struct req_iterator iter; 587 struct bio_vec bvec; 588 589 rq_for_each_segment(bvec, req, iter) { 590 iov_iter_bvec(&to, ITER_BVEC | READ, 591 &bvec, 1, bvec.bv_len); 592 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL); 593 if (result <= 0) { 594 dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n", 595 result); 596 /* 597 * If we've disconnected or we only have 1 598 * connection then we need to make sure we 599 * complete this request, otherwise error out 600 * and let the timeout stuff handle resubmitting 601 * this request onto another connection. 602 */ 603 if (nbd_disconnected(config) || 604 config->num_connections <= 1) { 605 cmd->status = BLK_STS_IOERR; 606 return cmd; 607 } 608 return ERR_PTR(-EIO); 609 } 610 dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n", 611 cmd, bvec.bv_len); 612 } 613 } else { 614 /* See the comment in nbd_queue_rq. */ 615 wait_for_completion(&cmd->send_complete); 616 } 617 return cmd; 618 } 619 620 static void recv_work(struct work_struct *work) 621 { 622 struct recv_thread_args *args = container_of(work, 623 struct recv_thread_args, 624 work); 625 struct nbd_device *nbd = args->nbd; 626 struct nbd_config *config = nbd->config; 627 struct nbd_cmd *cmd; 628 629 while (1) { 630 cmd = nbd_read_stat(nbd, args->index); 631 if (IS_ERR(cmd)) { 632 struct nbd_sock *nsock = config->socks[args->index]; 633 634 mutex_lock(&nsock->tx_lock); 635 nbd_mark_nsock_dead(nbd, nsock, 1); 636 mutex_unlock(&nsock->tx_lock); 637 break; 638 } 639 640 blk_mq_complete_request(blk_mq_rq_from_pdu(cmd)); 641 } 642 atomic_dec(&config->recv_threads); 643 wake_up(&config->recv_wq); 644 nbd_config_put(nbd); 645 kfree(args); 646 } 647 648 static void nbd_clear_req(struct request *req, void *data, bool reserved) 649 { 650 struct nbd_cmd *cmd; 651 652 if (!blk_mq_request_started(req)) 653 return; 654 cmd = blk_mq_rq_to_pdu(req); 655 cmd->status = BLK_STS_IOERR; 656 blk_mq_complete_request(req); 657 } 658 659 static void nbd_clear_que(struct nbd_device *nbd) 660 { 661 blk_mq_quiesce_queue(nbd->disk->queue); 662 blk_mq_tagset_busy_iter(&nbd->tag_set, nbd_clear_req, NULL); 663 blk_mq_unquiesce_queue(nbd->disk->queue); 664 dev_dbg(disk_to_dev(nbd->disk), "queue cleared\n"); 665 } 666 667 static int find_fallback(struct nbd_device *nbd, int index) 668 { 669 struct nbd_config *config = nbd->config; 670 int new_index = -1; 671 struct nbd_sock *nsock = config->socks[index]; 672 int fallback = nsock->fallback_index; 673 674 if (test_bit(NBD_DISCONNECTED, &config->runtime_flags)) 675 return new_index; 676 677 if (config->num_connections <= 1) { 678 dev_err_ratelimited(disk_to_dev(nbd->disk), 679 "Attempted send on invalid socket\n"); 680 return new_index; 681 } 682 683 if (fallback >= 0 && fallback < config->num_connections && 684 !config->socks[fallback]->dead) 685 return fallback; 686 687 if (nsock->fallback_index < 0 || 688 nsock->fallback_index >= config->num_connections || 689 config->socks[nsock->fallback_index]->dead) { 690 int i; 691 for (i = 0; i < config->num_connections; i++) { 692 if (i == index) 693 continue; 694 if (!config->socks[i]->dead) { 695 new_index = i; 696 break; 697 } 698 } 699 nsock->fallback_index = new_index; 700 if (new_index < 0) { 701 dev_err_ratelimited(disk_to_dev(nbd->disk), 702 "Dead connection, failed to find a fallback\n"); 703 return new_index; 704 } 705 } 706 new_index = nsock->fallback_index; 707 return new_index; 708 } 709 710 static int wait_for_reconnect(struct nbd_device *nbd) 711 { 712 struct nbd_config *config = nbd->config; 713 if (!config->dead_conn_timeout) 714 return 0; 715 if (test_bit(NBD_DISCONNECTED, &config->runtime_flags)) 716 return 0; 717 wait_event_timeout(config->conn_wait, 718 atomic_read(&config->live_connections), 719 config->dead_conn_timeout); 720 return atomic_read(&config->live_connections); 721 } 722 723 static int nbd_handle_cmd(struct nbd_cmd *cmd, int index) 724 { 725 struct request *req = blk_mq_rq_from_pdu(cmd); 726 struct nbd_device *nbd = cmd->nbd; 727 struct nbd_config *config; 728 struct nbd_sock *nsock; 729 int ret; 730 731 if (!refcount_inc_not_zero(&nbd->config_refs)) { 732 dev_err_ratelimited(disk_to_dev(nbd->disk), 733 "Socks array is empty\n"); 734 blk_mq_start_request(req); 735 return -EINVAL; 736 } 737 config = nbd->config; 738 739 if (index >= config->num_connections) { 740 dev_err_ratelimited(disk_to_dev(nbd->disk), 741 "Attempted send on invalid socket\n"); 742 nbd_config_put(nbd); 743 blk_mq_start_request(req); 744 return -EINVAL; 745 } 746 cmd->status = BLK_STS_OK; 747 again: 748 nsock = config->socks[index]; 749 mutex_lock(&nsock->tx_lock); 750 if (nsock->dead) { 751 int old_index = index; 752 index = find_fallback(nbd, index); 753 mutex_unlock(&nsock->tx_lock); 754 if (index < 0) { 755 if (wait_for_reconnect(nbd)) { 756 index = old_index; 757 goto again; 758 } 759 /* All the sockets should already be down at this point, 760 * we just want to make sure that DISCONNECTED is set so 761 * any requests that come in that were queue'ed waiting 762 * for the reconnect timer don't trigger the timer again 763 * and instead just error out. 764 */ 765 sock_shutdown(nbd); 766 nbd_config_put(nbd); 767 blk_mq_start_request(req); 768 return -EIO; 769 } 770 goto again; 771 } 772 773 /* Handle the case that we have a pending request that was partially 774 * transmitted that _has_ to be serviced first. We need to call requeue 775 * here so that it gets put _after_ the request that is already on the 776 * dispatch list. 777 */ 778 blk_mq_start_request(req); 779 if (unlikely(nsock->pending && nsock->pending != req)) { 780 blk_mq_requeue_request(req, true); 781 ret = 0; 782 goto out; 783 } 784 /* 785 * Some failures are related to the link going down, so anything that 786 * returns EAGAIN can be retried on a different socket. 787 */ 788 ret = nbd_send_cmd(nbd, cmd, index); 789 if (ret == -EAGAIN) { 790 dev_err_ratelimited(disk_to_dev(nbd->disk), 791 "Request send failed, requeueing\n"); 792 nbd_mark_nsock_dead(nbd, nsock, 1); 793 blk_mq_requeue_request(req, true); 794 ret = 0; 795 } 796 out: 797 mutex_unlock(&nsock->tx_lock); 798 nbd_config_put(nbd); 799 return ret; 800 } 801 802 static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx, 803 const struct blk_mq_queue_data *bd) 804 { 805 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(bd->rq); 806 int ret; 807 808 /* 809 * Since we look at the bio's to send the request over the network we 810 * need to make sure the completion work doesn't mark this request done 811 * before we are done doing our send. This keeps us from dereferencing 812 * freed data if we have particularly fast completions (ie we get the 813 * completion before we exit sock_xmit on the last bvec) or in the case 814 * that the server is misbehaving (or there was an error) before we're 815 * done sending everything over the wire. 816 */ 817 init_completion(&cmd->send_complete); 818 819 /* We can be called directly from the user space process, which means we 820 * could possibly have signals pending so our sendmsg will fail. In 821 * this case we need to return that we are busy, otherwise error out as 822 * appropriate. 823 */ 824 ret = nbd_handle_cmd(cmd, hctx->queue_num); 825 if (ret < 0) 826 ret = BLK_STS_IOERR; 827 else if (!ret) 828 ret = BLK_STS_OK; 829 complete(&cmd->send_complete); 830 831 return ret; 832 } 833 834 static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg, 835 bool netlink) 836 { 837 struct nbd_config *config = nbd->config; 838 struct socket *sock; 839 struct nbd_sock **socks; 840 struct nbd_sock *nsock; 841 int err; 842 843 sock = sockfd_lookup(arg, &err); 844 if (!sock) 845 return err; 846 847 if (!netlink && !nbd->task_setup && 848 !test_bit(NBD_BOUND, &config->runtime_flags)) 849 nbd->task_setup = current; 850 851 if (!netlink && 852 (nbd->task_setup != current || 853 test_bit(NBD_BOUND, &config->runtime_flags))) { 854 dev_err(disk_to_dev(nbd->disk), 855 "Device being setup by another task"); 856 sockfd_put(sock); 857 return -EBUSY; 858 } 859 860 socks = krealloc(config->socks, (config->num_connections + 1) * 861 sizeof(struct nbd_sock *), GFP_KERNEL); 862 if (!socks) { 863 sockfd_put(sock); 864 return -ENOMEM; 865 } 866 nsock = kzalloc(sizeof(struct nbd_sock), GFP_KERNEL); 867 if (!nsock) { 868 sockfd_put(sock); 869 return -ENOMEM; 870 } 871 872 config->socks = socks; 873 874 nsock->fallback_index = -1; 875 nsock->dead = false; 876 mutex_init(&nsock->tx_lock); 877 nsock->sock = sock; 878 nsock->pending = NULL; 879 nsock->sent = 0; 880 nsock->cookie = 0; 881 socks[config->num_connections++] = nsock; 882 atomic_inc(&config->live_connections); 883 884 return 0; 885 } 886 887 static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg) 888 { 889 struct nbd_config *config = nbd->config; 890 struct socket *sock, *old; 891 struct recv_thread_args *args; 892 int i; 893 int err; 894 895 sock = sockfd_lookup(arg, &err); 896 if (!sock) 897 return err; 898 899 args = kzalloc(sizeof(*args), GFP_KERNEL); 900 if (!args) { 901 sockfd_put(sock); 902 return -ENOMEM; 903 } 904 905 for (i = 0; i < config->num_connections; i++) { 906 struct nbd_sock *nsock = config->socks[i]; 907 908 if (!nsock->dead) 909 continue; 910 911 mutex_lock(&nsock->tx_lock); 912 if (!nsock->dead) { 913 mutex_unlock(&nsock->tx_lock); 914 continue; 915 } 916 sk_set_memalloc(sock->sk); 917 if (nbd->tag_set.timeout) 918 sock->sk->sk_sndtimeo = nbd->tag_set.timeout; 919 atomic_inc(&config->recv_threads); 920 refcount_inc(&nbd->config_refs); 921 old = nsock->sock; 922 nsock->fallback_index = -1; 923 nsock->sock = sock; 924 nsock->dead = false; 925 INIT_WORK(&args->work, recv_work); 926 args->index = i; 927 args->nbd = nbd; 928 nsock->cookie++; 929 mutex_unlock(&nsock->tx_lock); 930 sockfd_put(old); 931 932 clear_bit(NBD_DISCONNECTED, &config->runtime_flags); 933 934 /* We take the tx_mutex in an error path in the recv_work, so we 935 * need to queue_work outside of the tx_mutex. 936 */ 937 queue_work(recv_workqueue, &args->work); 938 939 atomic_inc(&config->live_connections); 940 wake_up(&config->conn_wait); 941 return 0; 942 } 943 sockfd_put(sock); 944 kfree(args); 945 return -ENOSPC; 946 } 947 948 static void nbd_bdev_reset(struct block_device *bdev) 949 { 950 if (bdev->bd_openers > 1) 951 return; 952 bd_set_size(bdev, 0); 953 if (max_part > 0) { 954 blkdev_reread_part(bdev); 955 bdev->bd_invalidated = 1; 956 } 957 } 958 959 static void nbd_parse_flags(struct nbd_device *nbd) 960 { 961 struct nbd_config *config = nbd->config; 962 if (config->flags & NBD_FLAG_READ_ONLY) 963 set_disk_ro(nbd->disk, true); 964 else 965 set_disk_ro(nbd->disk, false); 966 if (config->flags & NBD_FLAG_SEND_TRIM) 967 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue); 968 if (config->flags & NBD_FLAG_SEND_FLUSH) { 969 if (config->flags & NBD_FLAG_SEND_FUA) 970 blk_queue_write_cache(nbd->disk->queue, true, true); 971 else 972 blk_queue_write_cache(nbd->disk->queue, true, false); 973 } 974 else 975 blk_queue_write_cache(nbd->disk->queue, false, false); 976 } 977 978 static void send_disconnects(struct nbd_device *nbd) 979 { 980 struct nbd_config *config = nbd->config; 981 struct nbd_request request = { 982 .magic = htonl(NBD_REQUEST_MAGIC), 983 .type = htonl(NBD_CMD_DISC), 984 }; 985 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)}; 986 struct iov_iter from; 987 int i, ret; 988 989 for (i = 0; i < config->num_connections; i++) { 990 struct nbd_sock *nsock = config->socks[i]; 991 992 iov_iter_kvec(&from, WRITE | ITER_KVEC, &iov, 1, sizeof(request)); 993 mutex_lock(&nsock->tx_lock); 994 ret = sock_xmit(nbd, i, 1, &from, 0, NULL); 995 if (ret <= 0) 996 dev_err(disk_to_dev(nbd->disk), 997 "Send disconnect failed %d\n", ret); 998 mutex_unlock(&nsock->tx_lock); 999 } 1000 } 1001 1002 static int nbd_disconnect(struct nbd_device *nbd) 1003 { 1004 struct nbd_config *config = nbd->config; 1005 1006 dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n"); 1007 set_bit(NBD_DISCONNECT_REQUESTED, &config->runtime_flags); 1008 send_disconnects(nbd); 1009 return 0; 1010 } 1011 1012 static void nbd_clear_sock(struct nbd_device *nbd) 1013 { 1014 sock_shutdown(nbd); 1015 nbd_clear_que(nbd); 1016 nbd->task_setup = NULL; 1017 } 1018 1019 static void nbd_config_put(struct nbd_device *nbd) 1020 { 1021 if (refcount_dec_and_mutex_lock(&nbd->config_refs, 1022 &nbd->config_lock)) { 1023 struct nbd_config *config = nbd->config; 1024 nbd_dev_dbg_close(nbd); 1025 nbd_size_clear(nbd); 1026 if (test_and_clear_bit(NBD_HAS_PID_FILE, 1027 &config->runtime_flags)) 1028 device_remove_file(disk_to_dev(nbd->disk), &pid_attr); 1029 nbd->task_recv = NULL; 1030 nbd_clear_sock(nbd); 1031 if (config->num_connections) { 1032 int i; 1033 for (i = 0; i < config->num_connections; i++) { 1034 sockfd_put(config->socks[i]->sock); 1035 kfree(config->socks[i]); 1036 } 1037 kfree(config->socks); 1038 } 1039 kfree(nbd->config); 1040 nbd->config = NULL; 1041 1042 nbd->tag_set.timeout = 0; 1043 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue); 1044 1045 mutex_unlock(&nbd->config_lock); 1046 nbd_put(nbd); 1047 module_put(THIS_MODULE); 1048 } 1049 } 1050 1051 static int nbd_start_device(struct nbd_device *nbd) 1052 { 1053 struct nbd_config *config = nbd->config; 1054 int num_connections = config->num_connections; 1055 int error = 0, i; 1056 1057 if (nbd->task_recv) 1058 return -EBUSY; 1059 if (!config->socks) 1060 return -EINVAL; 1061 if (num_connections > 1 && 1062 !(config->flags & NBD_FLAG_CAN_MULTI_CONN)) { 1063 dev_err(disk_to_dev(nbd->disk), "server does not support multiple connections per device.\n"); 1064 return -EINVAL; 1065 } 1066 1067 blk_mq_update_nr_hw_queues(&nbd->tag_set, config->num_connections); 1068 nbd->task_recv = current; 1069 1070 nbd_parse_flags(nbd); 1071 1072 error = device_create_file(disk_to_dev(nbd->disk), &pid_attr); 1073 if (error) { 1074 dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n"); 1075 return error; 1076 } 1077 set_bit(NBD_HAS_PID_FILE, &config->runtime_flags); 1078 1079 nbd_dev_dbg_init(nbd); 1080 for (i = 0; i < num_connections; i++) { 1081 struct recv_thread_args *args; 1082 1083 args = kzalloc(sizeof(*args), GFP_KERNEL); 1084 if (!args) { 1085 sock_shutdown(nbd); 1086 return -ENOMEM; 1087 } 1088 sk_set_memalloc(config->socks[i]->sock->sk); 1089 if (nbd->tag_set.timeout) 1090 config->socks[i]->sock->sk->sk_sndtimeo = 1091 nbd->tag_set.timeout; 1092 atomic_inc(&config->recv_threads); 1093 refcount_inc(&nbd->config_refs); 1094 INIT_WORK(&args->work, recv_work); 1095 args->nbd = nbd; 1096 args->index = i; 1097 queue_work(recv_workqueue, &args->work); 1098 } 1099 nbd_size_update(nbd); 1100 return error; 1101 } 1102 1103 static int nbd_start_device_ioctl(struct nbd_device *nbd, struct block_device *bdev) 1104 { 1105 struct nbd_config *config = nbd->config; 1106 int ret; 1107 1108 ret = nbd_start_device(nbd); 1109 if (ret) 1110 return ret; 1111 1112 bd_set_size(bdev, config->bytesize); 1113 if (max_part) 1114 bdev->bd_invalidated = 1; 1115 mutex_unlock(&nbd->config_lock); 1116 ret = wait_event_interruptible(config->recv_wq, 1117 atomic_read(&config->recv_threads) == 0); 1118 if (ret) 1119 sock_shutdown(nbd); 1120 mutex_lock(&nbd->config_lock); 1121 bd_set_size(bdev, 0); 1122 /* user requested, ignore socket errors */ 1123 if (test_bit(NBD_DISCONNECT_REQUESTED, &config->runtime_flags)) 1124 ret = 0; 1125 if (test_bit(NBD_TIMEDOUT, &config->runtime_flags)) 1126 ret = -ETIMEDOUT; 1127 return ret; 1128 } 1129 1130 static void nbd_clear_sock_ioctl(struct nbd_device *nbd, 1131 struct block_device *bdev) 1132 { 1133 sock_shutdown(nbd); 1134 kill_bdev(bdev); 1135 nbd_bdev_reset(bdev); 1136 if (test_and_clear_bit(NBD_HAS_CONFIG_REF, 1137 &nbd->config->runtime_flags)) 1138 nbd_config_put(nbd); 1139 } 1140 1141 /* Must be called with config_lock held */ 1142 static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd, 1143 unsigned int cmd, unsigned long arg) 1144 { 1145 struct nbd_config *config = nbd->config; 1146 1147 switch (cmd) { 1148 case NBD_DISCONNECT: 1149 return nbd_disconnect(nbd); 1150 case NBD_CLEAR_SOCK: 1151 nbd_clear_sock_ioctl(nbd, bdev); 1152 return 0; 1153 case NBD_SET_SOCK: 1154 return nbd_add_socket(nbd, arg, false); 1155 case NBD_SET_BLKSIZE: 1156 nbd_size_set(nbd, arg, 1157 div_s64(config->bytesize, arg)); 1158 return 0; 1159 case NBD_SET_SIZE: 1160 nbd_size_set(nbd, config->blksize, 1161 div_s64(arg, config->blksize)); 1162 return 0; 1163 case NBD_SET_SIZE_BLOCKS: 1164 nbd_size_set(nbd, config->blksize, arg); 1165 return 0; 1166 case NBD_SET_TIMEOUT: 1167 if (arg) { 1168 nbd->tag_set.timeout = arg * HZ; 1169 blk_queue_rq_timeout(nbd->disk->queue, arg * HZ); 1170 } 1171 return 0; 1172 1173 case NBD_SET_FLAGS: 1174 config->flags = arg; 1175 return 0; 1176 case NBD_DO_IT: 1177 return nbd_start_device_ioctl(nbd, bdev); 1178 case NBD_CLEAR_QUE: 1179 /* 1180 * This is for compatibility only. The queue is always cleared 1181 * by NBD_DO_IT or NBD_CLEAR_SOCK. 1182 */ 1183 return 0; 1184 case NBD_PRINT_DEBUG: 1185 /* 1186 * For compatibility only, we no longer keep a list of 1187 * outstanding requests. 1188 */ 1189 return 0; 1190 } 1191 return -ENOTTY; 1192 } 1193 1194 static int nbd_ioctl(struct block_device *bdev, fmode_t mode, 1195 unsigned int cmd, unsigned long arg) 1196 { 1197 struct nbd_device *nbd = bdev->bd_disk->private_data; 1198 struct nbd_config *config = nbd->config; 1199 int error = -EINVAL; 1200 1201 if (!capable(CAP_SYS_ADMIN)) 1202 return -EPERM; 1203 1204 /* The block layer will pass back some non-nbd ioctls in case we have 1205 * special handling for them, but we don't so just return an error. 1206 */ 1207 if (_IOC_TYPE(cmd) != 0xab) 1208 return -EINVAL; 1209 1210 mutex_lock(&nbd->config_lock); 1211 1212 /* Don't allow ioctl operations on a nbd device that was created with 1213 * netlink, unless it's DISCONNECT or CLEAR_SOCK, which are fine. 1214 */ 1215 if (!test_bit(NBD_BOUND, &config->runtime_flags) || 1216 (cmd == NBD_DISCONNECT || cmd == NBD_CLEAR_SOCK)) 1217 error = __nbd_ioctl(bdev, nbd, cmd, arg); 1218 else 1219 dev_err(nbd_to_dev(nbd), "Cannot use ioctl interface on a netlink controlled device.\n"); 1220 mutex_unlock(&nbd->config_lock); 1221 return error; 1222 } 1223 1224 static struct nbd_config *nbd_alloc_config(void) 1225 { 1226 struct nbd_config *config; 1227 1228 config = kzalloc(sizeof(struct nbd_config), GFP_NOFS); 1229 if (!config) 1230 return NULL; 1231 atomic_set(&config->recv_threads, 0); 1232 init_waitqueue_head(&config->recv_wq); 1233 init_waitqueue_head(&config->conn_wait); 1234 config->blksize = 1024; 1235 atomic_set(&config->live_connections, 0); 1236 try_module_get(THIS_MODULE); 1237 return config; 1238 } 1239 1240 static int nbd_open(struct block_device *bdev, fmode_t mode) 1241 { 1242 struct nbd_device *nbd; 1243 int ret = 0; 1244 1245 mutex_lock(&nbd_index_mutex); 1246 nbd = bdev->bd_disk->private_data; 1247 if (!nbd) { 1248 ret = -ENXIO; 1249 goto out; 1250 } 1251 if (!refcount_inc_not_zero(&nbd->refs)) { 1252 ret = -ENXIO; 1253 goto out; 1254 } 1255 if (!refcount_inc_not_zero(&nbd->config_refs)) { 1256 struct nbd_config *config; 1257 1258 mutex_lock(&nbd->config_lock); 1259 if (refcount_inc_not_zero(&nbd->config_refs)) { 1260 mutex_unlock(&nbd->config_lock); 1261 goto out; 1262 } 1263 config = nbd->config = nbd_alloc_config(); 1264 if (!config) { 1265 ret = -ENOMEM; 1266 mutex_unlock(&nbd->config_lock); 1267 goto out; 1268 } 1269 refcount_set(&nbd->config_refs, 1); 1270 refcount_inc(&nbd->refs); 1271 mutex_unlock(&nbd->config_lock); 1272 } 1273 out: 1274 mutex_unlock(&nbd_index_mutex); 1275 return ret; 1276 } 1277 1278 static void nbd_release(struct gendisk *disk, fmode_t mode) 1279 { 1280 struct nbd_device *nbd = disk->private_data; 1281 nbd_config_put(nbd); 1282 nbd_put(nbd); 1283 } 1284 1285 static const struct block_device_operations nbd_fops = 1286 { 1287 .owner = THIS_MODULE, 1288 .open = nbd_open, 1289 .release = nbd_release, 1290 .ioctl = nbd_ioctl, 1291 .compat_ioctl = nbd_ioctl, 1292 }; 1293 1294 #if IS_ENABLED(CONFIG_DEBUG_FS) 1295 1296 static int nbd_dbg_tasks_show(struct seq_file *s, void *unused) 1297 { 1298 struct nbd_device *nbd = s->private; 1299 1300 if (nbd->task_recv) 1301 seq_printf(s, "recv: %d\n", task_pid_nr(nbd->task_recv)); 1302 1303 return 0; 1304 } 1305 1306 static int nbd_dbg_tasks_open(struct inode *inode, struct file *file) 1307 { 1308 return single_open(file, nbd_dbg_tasks_show, inode->i_private); 1309 } 1310 1311 static const struct file_operations nbd_dbg_tasks_ops = { 1312 .open = nbd_dbg_tasks_open, 1313 .read = seq_read, 1314 .llseek = seq_lseek, 1315 .release = single_release, 1316 }; 1317 1318 static int nbd_dbg_flags_show(struct seq_file *s, void *unused) 1319 { 1320 struct nbd_device *nbd = s->private; 1321 u32 flags = nbd->config->flags; 1322 1323 seq_printf(s, "Hex: 0x%08x\n\n", flags); 1324 1325 seq_puts(s, "Known flags:\n"); 1326 1327 if (flags & NBD_FLAG_HAS_FLAGS) 1328 seq_puts(s, "NBD_FLAG_HAS_FLAGS\n"); 1329 if (flags & NBD_FLAG_READ_ONLY) 1330 seq_puts(s, "NBD_FLAG_READ_ONLY\n"); 1331 if (flags & NBD_FLAG_SEND_FLUSH) 1332 seq_puts(s, "NBD_FLAG_SEND_FLUSH\n"); 1333 if (flags & NBD_FLAG_SEND_FUA) 1334 seq_puts(s, "NBD_FLAG_SEND_FUA\n"); 1335 if (flags & NBD_FLAG_SEND_TRIM) 1336 seq_puts(s, "NBD_FLAG_SEND_TRIM\n"); 1337 1338 return 0; 1339 } 1340 1341 static int nbd_dbg_flags_open(struct inode *inode, struct file *file) 1342 { 1343 return single_open(file, nbd_dbg_flags_show, inode->i_private); 1344 } 1345 1346 static const struct file_operations nbd_dbg_flags_ops = { 1347 .open = nbd_dbg_flags_open, 1348 .read = seq_read, 1349 .llseek = seq_lseek, 1350 .release = single_release, 1351 }; 1352 1353 static int nbd_dev_dbg_init(struct nbd_device *nbd) 1354 { 1355 struct dentry *dir; 1356 struct nbd_config *config = nbd->config; 1357 1358 if (!nbd_dbg_dir) 1359 return -EIO; 1360 1361 dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir); 1362 if (!dir) { 1363 dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s'\n", 1364 nbd_name(nbd)); 1365 return -EIO; 1366 } 1367 config->dbg_dir = dir; 1368 1369 debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_ops); 1370 debugfs_create_u64("size_bytes", 0444, dir, &config->bytesize); 1371 debugfs_create_u32("timeout", 0444, dir, &nbd->tag_set.timeout); 1372 debugfs_create_u64("blocksize", 0444, dir, &config->blksize); 1373 debugfs_create_file("flags", 0444, dir, nbd, &nbd_dbg_flags_ops); 1374 1375 return 0; 1376 } 1377 1378 static void nbd_dev_dbg_close(struct nbd_device *nbd) 1379 { 1380 debugfs_remove_recursive(nbd->config->dbg_dir); 1381 } 1382 1383 static int nbd_dbg_init(void) 1384 { 1385 struct dentry *dbg_dir; 1386 1387 dbg_dir = debugfs_create_dir("nbd", NULL); 1388 if (!dbg_dir) 1389 return -EIO; 1390 1391 nbd_dbg_dir = dbg_dir; 1392 1393 return 0; 1394 } 1395 1396 static void nbd_dbg_close(void) 1397 { 1398 debugfs_remove_recursive(nbd_dbg_dir); 1399 } 1400 1401 #else /* IS_ENABLED(CONFIG_DEBUG_FS) */ 1402 1403 static int nbd_dev_dbg_init(struct nbd_device *nbd) 1404 { 1405 return 0; 1406 } 1407 1408 static void nbd_dev_dbg_close(struct nbd_device *nbd) 1409 { 1410 } 1411 1412 static int nbd_dbg_init(void) 1413 { 1414 return 0; 1415 } 1416 1417 static void nbd_dbg_close(void) 1418 { 1419 } 1420 1421 #endif 1422 1423 static int nbd_init_request(struct blk_mq_tag_set *set, struct request *rq, 1424 unsigned int hctx_idx, unsigned int numa_node) 1425 { 1426 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq); 1427 cmd->nbd = set->driver_data; 1428 return 0; 1429 } 1430 1431 static const struct blk_mq_ops nbd_mq_ops = { 1432 .queue_rq = nbd_queue_rq, 1433 .complete = nbd_complete_rq, 1434 .init_request = nbd_init_request, 1435 .timeout = nbd_xmit_timeout, 1436 }; 1437 1438 static int nbd_dev_add(int index) 1439 { 1440 struct nbd_device *nbd; 1441 struct gendisk *disk; 1442 struct request_queue *q; 1443 int err = -ENOMEM; 1444 1445 nbd = kzalloc(sizeof(struct nbd_device), GFP_KERNEL); 1446 if (!nbd) 1447 goto out; 1448 1449 disk = alloc_disk(1 << part_shift); 1450 if (!disk) 1451 goto out_free_nbd; 1452 1453 if (index >= 0) { 1454 err = idr_alloc(&nbd_index_idr, nbd, index, index + 1, 1455 GFP_KERNEL); 1456 if (err == -ENOSPC) 1457 err = -EEXIST; 1458 } else { 1459 err = idr_alloc(&nbd_index_idr, nbd, 0, 0, GFP_KERNEL); 1460 if (err >= 0) 1461 index = err; 1462 } 1463 if (err < 0) 1464 goto out_free_disk; 1465 1466 nbd->index = index; 1467 nbd->disk = disk; 1468 nbd->tag_set.ops = &nbd_mq_ops; 1469 nbd->tag_set.nr_hw_queues = 1; 1470 nbd->tag_set.queue_depth = 128; 1471 nbd->tag_set.numa_node = NUMA_NO_NODE; 1472 nbd->tag_set.cmd_size = sizeof(struct nbd_cmd); 1473 nbd->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | 1474 BLK_MQ_F_SG_MERGE | BLK_MQ_F_BLOCKING; 1475 nbd->tag_set.driver_data = nbd; 1476 1477 err = blk_mq_alloc_tag_set(&nbd->tag_set); 1478 if (err) 1479 goto out_free_idr; 1480 1481 q = blk_mq_init_queue(&nbd->tag_set); 1482 if (IS_ERR(q)) { 1483 err = PTR_ERR(q); 1484 goto out_free_tags; 1485 } 1486 disk->queue = q; 1487 1488 /* 1489 * Tell the block layer that we are not a rotational device 1490 */ 1491 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue); 1492 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, disk->queue); 1493 disk->queue->limits.discard_granularity = 512; 1494 blk_queue_max_discard_sectors(disk->queue, UINT_MAX); 1495 blk_queue_max_segment_size(disk->queue, UINT_MAX); 1496 blk_queue_max_segments(disk->queue, USHRT_MAX); 1497 blk_queue_max_hw_sectors(disk->queue, 65536); 1498 disk->queue->limits.max_sectors = 256; 1499 1500 mutex_init(&nbd->config_lock); 1501 refcount_set(&nbd->config_refs, 0); 1502 refcount_set(&nbd->refs, 1); 1503 INIT_LIST_HEAD(&nbd->list); 1504 disk->major = NBD_MAJOR; 1505 disk->first_minor = index << part_shift; 1506 disk->fops = &nbd_fops; 1507 disk->private_data = nbd; 1508 sprintf(disk->disk_name, "nbd%d", index); 1509 add_disk(disk); 1510 nbd_total_devices++; 1511 return index; 1512 1513 out_free_tags: 1514 blk_mq_free_tag_set(&nbd->tag_set); 1515 out_free_idr: 1516 idr_remove(&nbd_index_idr, index); 1517 out_free_disk: 1518 put_disk(disk); 1519 out_free_nbd: 1520 kfree(nbd); 1521 out: 1522 return err; 1523 } 1524 1525 static int find_free_cb(int id, void *ptr, void *data) 1526 { 1527 struct nbd_device *nbd = ptr; 1528 struct nbd_device **found = data; 1529 1530 if (!refcount_read(&nbd->config_refs)) { 1531 *found = nbd; 1532 return 1; 1533 } 1534 return 0; 1535 } 1536 1537 /* Netlink interface. */ 1538 static struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = { 1539 [NBD_ATTR_INDEX] = { .type = NLA_U32 }, 1540 [NBD_ATTR_SIZE_BYTES] = { .type = NLA_U64 }, 1541 [NBD_ATTR_BLOCK_SIZE_BYTES] = { .type = NLA_U64 }, 1542 [NBD_ATTR_TIMEOUT] = { .type = NLA_U64 }, 1543 [NBD_ATTR_SERVER_FLAGS] = { .type = NLA_U64 }, 1544 [NBD_ATTR_CLIENT_FLAGS] = { .type = NLA_U64 }, 1545 [NBD_ATTR_SOCKETS] = { .type = NLA_NESTED}, 1546 [NBD_ATTR_DEAD_CONN_TIMEOUT] = { .type = NLA_U64 }, 1547 [NBD_ATTR_DEVICE_LIST] = { .type = NLA_NESTED}, 1548 }; 1549 1550 static struct nla_policy nbd_sock_policy[NBD_SOCK_MAX + 1] = { 1551 [NBD_SOCK_FD] = { .type = NLA_U32 }, 1552 }; 1553 1554 /* We don't use this right now since we don't parse the incoming list, but we 1555 * still want it here so userspace knows what to expect. 1556 */ 1557 static struct nla_policy __attribute__((unused)) 1558 nbd_device_policy[NBD_DEVICE_ATTR_MAX + 1] = { 1559 [NBD_DEVICE_INDEX] = { .type = NLA_U32 }, 1560 [NBD_DEVICE_CONNECTED] = { .type = NLA_U8 }, 1561 }; 1562 1563 static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info) 1564 { 1565 struct nbd_device *nbd = NULL; 1566 struct nbd_config *config; 1567 int index = -1; 1568 int ret; 1569 bool put_dev = false; 1570 1571 if (!netlink_capable(skb, CAP_SYS_ADMIN)) 1572 return -EPERM; 1573 1574 if (info->attrs[NBD_ATTR_INDEX]) 1575 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]); 1576 if (!info->attrs[NBD_ATTR_SOCKETS]) { 1577 printk(KERN_ERR "nbd: must specify at least one socket\n"); 1578 return -EINVAL; 1579 } 1580 if (!info->attrs[NBD_ATTR_SIZE_BYTES]) { 1581 printk(KERN_ERR "nbd: must specify a size in bytes for the device\n"); 1582 return -EINVAL; 1583 } 1584 again: 1585 mutex_lock(&nbd_index_mutex); 1586 if (index == -1) { 1587 ret = idr_for_each(&nbd_index_idr, &find_free_cb, &nbd); 1588 if (ret == 0) { 1589 int new_index; 1590 new_index = nbd_dev_add(-1); 1591 if (new_index < 0) { 1592 mutex_unlock(&nbd_index_mutex); 1593 printk(KERN_ERR "nbd: failed to add new device\n"); 1594 return ret; 1595 } 1596 nbd = idr_find(&nbd_index_idr, new_index); 1597 } 1598 } else { 1599 nbd = idr_find(&nbd_index_idr, index); 1600 if (!nbd) { 1601 ret = nbd_dev_add(index); 1602 if (ret < 0) { 1603 mutex_unlock(&nbd_index_mutex); 1604 printk(KERN_ERR "nbd: failed to add new device\n"); 1605 return ret; 1606 } 1607 nbd = idr_find(&nbd_index_idr, index); 1608 } 1609 } 1610 if (!nbd) { 1611 printk(KERN_ERR "nbd: couldn't find device at index %d\n", 1612 index); 1613 mutex_unlock(&nbd_index_mutex); 1614 return -EINVAL; 1615 } 1616 if (!refcount_inc_not_zero(&nbd->refs)) { 1617 mutex_unlock(&nbd_index_mutex); 1618 if (index == -1) 1619 goto again; 1620 printk(KERN_ERR "nbd: device at index %d is going down\n", 1621 index); 1622 return -EINVAL; 1623 } 1624 mutex_unlock(&nbd_index_mutex); 1625 1626 mutex_lock(&nbd->config_lock); 1627 if (refcount_read(&nbd->config_refs)) { 1628 mutex_unlock(&nbd->config_lock); 1629 nbd_put(nbd); 1630 if (index == -1) 1631 goto again; 1632 printk(KERN_ERR "nbd: nbd%d already in use\n", index); 1633 return -EBUSY; 1634 } 1635 if (WARN_ON(nbd->config)) { 1636 mutex_unlock(&nbd->config_lock); 1637 nbd_put(nbd); 1638 return -EINVAL; 1639 } 1640 config = nbd->config = nbd_alloc_config(); 1641 if (!nbd->config) { 1642 mutex_unlock(&nbd->config_lock); 1643 nbd_put(nbd); 1644 printk(KERN_ERR "nbd: couldn't allocate config\n"); 1645 return -ENOMEM; 1646 } 1647 refcount_set(&nbd->config_refs, 1); 1648 set_bit(NBD_BOUND, &config->runtime_flags); 1649 1650 if (info->attrs[NBD_ATTR_SIZE_BYTES]) { 1651 u64 bytes = nla_get_u64(info->attrs[NBD_ATTR_SIZE_BYTES]); 1652 nbd_size_set(nbd, config->blksize, 1653 div64_u64(bytes, config->blksize)); 1654 } 1655 if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]) { 1656 u64 bsize = 1657 nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]); 1658 nbd_size_set(nbd, bsize, div64_u64(config->bytesize, bsize)); 1659 } 1660 if (info->attrs[NBD_ATTR_TIMEOUT]) { 1661 u64 timeout = nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]); 1662 nbd->tag_set.timeout = timeout * HZ; 1663 blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ); 1664 } 1665 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) { 1666 config->dead_conn_timeout = 1667 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]); 1668 config->dead_conn_timeout *= HZ; 1669 } 1670 if (info->attrs[NBD_ATTR_SERVER_FLAGS]) 1671 config->flags = 1672 nla_get_u64(info->attrs[NBD_ATTR_SERVER_FLAGS]); 1673 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) { 1674 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]); 1675 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) { 1676 set_bit(NBD_DESTROY_ON_DISCONNECT, 1677 &config->runtime_flags); 1678 put_dev = true; 1679 } 1680 } 1681 1682 if (info->attrs[NBD_ATTR_SOCKETS]) { 1683 struct nlattr *attr; 1684 int rem, fd; 1685 1686 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS], 1687 rem) { 1688 struct nlattr *socks[NBD_SOCK_MAX+1]; 1689 1690 if (nla_type(attr) != NBD_SOCK_ITEM) { 1691 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n"); 1692 ret = -EINVAL; 1693 goto out; 1694 } 1695 ret = nla_parse_nested(socks, NBD_SOCK_MAX, attr, 1696 nbd_sock_policy, info->extack); 1697 if (ret != 0) { 1698 printk(KERN_ERR "nbd: error processing sock list\n"); 1699 ret = -EINVAL; 1700 goto out; 1701 } 1702 if (!socks[NBD_SOCK_FD]) 1703 continue; 1704 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]); 1705 ret = nbd_add_socket(nbd, fd, true); 1706 if (ret) 1707 goto out; 1708 } 1709 } 1710 ret = nbd_start_device(nbd); 1711 out: 1712 mutex_unlock(&nbd->config_lock); 1713 if (!ret) { 1714 set_bit(NBD_HAS_CONFIG_REF, &config->runtime_flags); 1715 refcount_inc(&nbd->config_refs); 1716 nbd_connect_reply(info, nbd->index); 1717 } 1718 nbd_config_put(nbd); 1719 if (put_dev) 1720 nbd_put(nbd); 1721 return ret; 1722 } 1723 1724 static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info) 1725 { 1726 struct nbd_device *nbd; 1727 int index; 1728 1729 if (!netlink_capable(skb, CAP_SYS_ADMIN)) 1730 return -EPERM; 1731 1732 if (!info->attrs[NBD_ATTR_INDEX]) { 1733 printk(KERN_ERR "nbd: must specify an index to disconnect\n"); 1734 return -EINVAL; 1735 } 1736 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]); 1737 mutex_lock(&nbd_index_mutex); 1738 nbd = idr_find(&nbd_index_idr, index); 1739 if (!nbd) { 1740 mutex_unlock(&nbd_index_mutex); 1741 printk(KERN_ERR "nbd: couldn't find device at index %d\n", 1742 index); 1743 return -EINVAL; 1744 } 1745 if (!refcount_inc_not_zero(&nbd->refs)) { 1746 mutex_unlock(&nbd_index_mutex); 1747 printk(KERN_ERR "nbd: device at index %d is going down\n", 1748 index); 1749 return -EINVAL; 1750 } 1751 mutex_unlock(&nbd_index_mutex); 1752 if (!refcount_inc_not_zero(&nbd->config_refs)) { 1753 nbd_put(nbd); 1754 return 0; 1755 } 1756 mutex_lock(&nbd->config_lock); 1757 nbd_disconnect(nbd); 1758 mutex_unlock(&nbd->config_lock); 1759 if (test_and_clear_bit(NBD_HAS_CONFIG_REF, 1760 &nbd->config->runtime_flags)) 1761 nbd_config_put(nbd); 1762 nbd_config_put(nbd); 1763 nbd_put(nbd); 1764 return 0; 1765 } 1766 1767 static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info) 1768 { 1769 struct nbd_device *nbd = NULL; 1770 struct nbd_config *config; 1771 int index; 1772 int ret = -EINVAL; 1773 bool put_dev = false; 1774 1775 if (!netlink_capable(skb, CAP_SYS_ADMIN)) 1776 return -EPERM; 1777 1778 if (!info->attrs[NBD_ATTR_INDEX]) { 1779 printk(KERN_ERR "nbd: must specify a device to reconfigure\n"); 1780 return -EINVAL; 1781 } 1782 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]); 1783 mutex_lock(&nbd_index_mutex); 1784 nbd = idr_find(&nbd_index_idr, index); 1785 if (!nbd) { 1786 mutex_unlock(&nbd_index_mutex); 1787 printk(KERN_ERR "nbd: couldn't find a device at index %d\n", 1788 index); 1789 return -EINVAL; 1790 } 1791 if (!refcount_inc_not_zero(&nbd->refs)) { 1792 mutex_unlock(&nbd_index_mutex); 1793 printk(KERN_ERR "nbd: device at index %d is going down\n", 1794 index); 1795 return -EINVAL; 1796 } 1797 mutex_unlock(&nbd_index_mutex); 1798 1799 if (!refcount_inc_not_zero(&nbd->config_refs)) { 1800 dev_err(nbd_to_dev(nbd), 1801 "not configured, cannot reconfigure\n"); 1802 nbd_put(nbd); 1803 return -EINVAL; 1804 } 1805 1806 mutex_lock(&nbd->config_lock); 1807 config = nbd->config; 1808 if (!test_bit(NBD_BOUND, &config->runtime_flags) || 1809 !nbd->task_recv) { 1810 dev_err(nbd_to_dev(nbd), 1811 "not configured, cannot reconfigure\n"); 1812 goto out; 1813 } 1814 1815 if (info->attrs[NBD_ATTR_TIMEOUT]) { 1816 u64 timeout = nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]); 1817 nbd->tag_set.timeout = timeout * HZ; 1818 blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ); 1819 } 1820 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) { 1821 config->dead_conn_timeout = 1822 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]); 1823 config->dead_conn_timeout *= HZ; 1824 } 1825 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) { 1826 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]); 1827 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) { 1828 if (!test_and_set_bit(NBD_DESTROY_ON_DISCONNECT, 1829 &config->runtime_flags)) 1830 put_dev = true; 1831 } else { 1832 if (test_and_clear_bit(NBD_DESTROY_ON_DISCONNECT, 1833 &config->runtime_flags)) 1834 refcount_inc(&nbd->refs); 1835 } 1836 } 1837 1838 if (info->attrs[NBD_ATTR_SOCKETS]) { 1839 struct nlattr *attr; 1840 int rem, fd; 1841 1842 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS], 1843 rem) { 1844 struct nlattr *socks[NBD_SOCK_MAX+1]; 1845 1846 if (nla_type(attr) != NBD_SOCK_ITEM) { 1847 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n"); 1848 ret = -EINVAL; 1849 goto out; 1850 } 1851 ret = nla_parse_nested(socks, NBD_SOCK_MAX, attr, 1852 nbd_sock_policy, info->extack); 1853 if (ret != 0) { 1854 printk(KERN_ERR "nbd: error processing sock list\n"); 1855 ret = -EINVAL; 1856 goto out; 1857 } 1858 if (!socks[NBD_SOCK_FD]) 1859 continue; 1860 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]); 1861 ret = nbd_reconnect_socket(nbd, fd); 1862 if (ret) { 1863 if (ret == -ENOSPC) 1864 ret = 0; 1865 goto out; 1866 } 1867 dev_info(nbd_to_dev(nbd), "reconnected socket\n"); 1868 } 1869 } 1870 out: 1871 mutex_unlock(&nbd->config_lock); 1872 nbd_config_put(nbd); 1873 nbd_put(nbd); 1874 if (put_dev) 1875 nbd_put(nbd); 1876 return ret; 1877 } 1878 1879 static const struct genl_ops nbd_connect_genl_ops[] = { 1880 { 1881 .cmd = NBD_CMD_CONNECT, 1882 .policy = nbd_attr_policy, 1883 .doit = nbd_genl_connect, 1884 }, 1885 { 1886 .cmd = NBD_CMD_DISCONNECT, 1887 .policy = nbd_attr_policy, 1888 .doit = nbd_genl_disconnect, 1889 }, 1890 { 1891 .cmd = NBD_CMD_RECONFIGURE, 1892 .policy = nbd_attr_policy, 1893 .doit = nbd_genl_reconfigure, 1894 }, 1895 { 1896 .cmd = NBD_CMD_STATUS, 1897 .policy = nbd_attr_policy, 1898 .doit = nbd_genl_status, 1899 }, 1900 }; 1901 1902 static const struct genl_multicast_group nbd_mcast_grps[] = { 1903 { .name = NBD_GENL_MCAST_GROUP_NAME, }, 1904 }; 1905 1906 static struct genl_family nbd_genl_family __ro_after_init = { 1907 .hdrsize = 0, 1908 .name = NBD_GENL_FAMILY_NAME, 1909 .version = NBD_GENL_VERSION, 1910 .module = THIS_MODULE, 1911 .ops = nbd_connect_genl_ops, 1912 .n_ops = ARRAY_SIZE(nbd_connect_genl_ops), 1913 .maxattr = NBD_ATTR_MAX, 1914 .mcgrps = nbd_mcast_grps, 1915 .n_mcgrps = ARRAY_SIZE(nbd_mcast_grps), 1916 }; 1917 1918 static int populate_nbd_status(struct nbd_device *nbd, struct sk_buff *reply) 1919 { 1920 struct nlattr *dev_opt; 1921 u8 connected = 0; 1922 int ret; 1923 1924 /* This is a little racey, but for status it's ok. The 1925 * reason we don't take a ref here is because we can't 1926 * take a ref in the index == -1 case as we would need 1927 * to put under the nbd_index_mutex, which could 1928 * deadlock if we are configured to remove ourselves 1929 * once we're disconnected. 1930 */ 1931 if (refcount_read(&nbd->config_refs)) 1932 connected = 1; 1933 dev_opt = nla_nest_start(reply, NBD_DEVICE_ITEM); 1934 if (!dev_opt) 1935 return -EMSGSIZE; 1936 ret = nla_put_u32(reply, NBD_DEVICE_INDEX, nbd->index); 1937 if (ret) 1938 return -EMSGSIZE; 1939 ret = nla_put_u8(reply, NBD_DEVICE_CONNECTED, 1940 connected); 1941 if (ret) 1942 return -EMSGSIZE; 1943 nla_nest_end(reply, dev_opt); 1944 return 0; 1945 } 1946 1947 static int status_cb(int id, void *ptr, void *data) 1948 { 1949 struct nbd_device *nbd = ptr; 1950 return populate_nbd_status(nbd, (struct sk_buff *)data); 1951 } 1952 1953 static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info) 1954 { 1955 struct nlattr *dev_list; 1956 struct sk_buff *reply; 1957 void *reply_head; 1958 size_t msg_size; 1959 int index = -1; 1960 int ret = -ENOMEM; 1961 1962 if (info->attrs[NBD_ATTR_INDEX]) 1963 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]); 1964 1965 mutex_lock(&nbd_index_mutex); 1966 1967 msg_size = nla_total_size(nla_attr_size(sizeof(u32)) + 1968 nla_attr_size(sizeof(u8))); 1969 msg_size *= (index == -1) ? nbd_total_devices : 1; 1970 1971 reply = genlmsg_new(msg_size, GFP_KERNEL); 1972 if (!reply) 1973 goto out; 1974 reply_head = genlmsg_put_reply(reply, info, &nbd_genl_family, 0, 1975 NBD_CMD_STATUS); 1976 if (!reply_head) { 1977 nlmsg_free(reply); 1978 goto out; 1979 } 1980 1981 dev_list = nla_nest_start(reply, NBD_ATTR_DEVICE_LIST); 1982 if (index == -1) { 1983 ret = idr_for_each(&nbd_index_idr, &status_cb, reply); 1984 if (ret) { 1985 nlmsg_free(reply); 1986 goto out; 1987 } 1988 } else { 1989 struct nbd_device *nbd; 1990 nbd = idr_find(&nbd_index_idr, index); 1991 if (nbd) { 1992 ret = populate_nbd_status(nbd, reply); 1993 if (ret) { 1994 nlmsg_free(reply); 1995 goto out; 1996 } 1997 } 1998 } 1999 nla_nest_end(reply, dev_list); 2000 genlmsg_end(reply, reply_head); 2001 genlmsg_reply(reply, info); 2002 ret = 0; 2003 out: 2004 mutex_unlock(&nbd_index_mutex); 2005 return ret; 2006 } 2007 2008 static void nbd_connect_reply(struct genl_info *info, int index) 2009 { 2010 struct sk_buff *skb; 2011 void *msg_head; 2012 int ret; 2013 2014 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL); 2015 if (!skb) 2016 return; 2017 msg_head = genlmsg_put_reply(skb, info, &nbd_genl_family, 0, 2018 NBD_CMD_CONNECT); 2019 if (!msg_head) { 2020 nlmsg_free(skb); 2021 return; 2022 } 2023 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index); 2024 if (ret) { 2025 nlmsg_free(skb); 2026 return; 2027 } 2028 genlmsg_end(skb, msg_head); 2029 genlmsg_reply(skb, info); 2030 } 2031 2032 static void nbd_mcast_index(int index) 2033 { 2034 struct sk_buff *skb; 2035 void *msg_head; 2036 int ret; 2037 2038 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL); 2039 if (!skb) 2040 return; 2041 msg_head = genlmsg_put(skb, 0, 0, &nbd_genl_family, 0, 2042 NBD_CMD_LINK_DEAD); 2043 if (!msg_head) { 2044 nlmsg_free(skb); 2045 return; 2046 } 2047 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index); 2048 if (ret) { 2049 nlmsg_free(skb); 2050 return; 2051 } 2052 genlmsg_end(skb, msg_head); 2053 genlmsg_multicast(&nbd_genl_family, skb, 0, 0, GFP_KERNEL); 2054 } 2055 2056 static void nbd_dead_link_work(struct work_struct *work) 2057 { 2058 struct link_dead_args *args = container_of(work, struct link_dead_args, 2059 work); 2060 nbd_mcast_index(args->index); 2061 kfree(args); 2062 } 2063 2064 static int __init nbd_init(void) 2065 { 2066 int i; 2067 2068 BUILD_BUG_ON(sizeof(struct nbd_request) != 28); 2069 2070 if (max_part < 0) { 2071 printk(KERN_ERR "nbd: max_part must be >= 0\n"); 2072 return -EINVAL; 2073 } 2074 2075 part_shift = 0; 2076 if (max_part > 0) { 2077 part_shift = fls(max_part); 2078 2079 /* 2080 * Adjust max_part according to part_shift as it is exported 2081 * to user space so that user can know the max number of 2082 * partition kernel should be able to manage. 2083 * 2084 * Note that -1 is required because partition 0 is reserved 2085 * for the whole disk. 2086 */ 2087 max_part = (1UL << part_shift) - 1; 2088 } 2089 2090 if ((1UL << part_shift) > DISK_MAX_PARTS) 2091 return -EINVAL; 2092 2093 if (nbds_max > 1UL << (MINORBITS - part_shift)) 2094 return -EINVAL; 2095 recv_workqueue = alloc_workqueue("knbd-recv", 2096 WQ_MEM_RECLAIM | WQ_HIGHPRI, 0); 2097 if (!recv_workqueue) 2098 return -ENOMEM; 2099 2100 if (register_blkdev(NBD_MAJOR, "nbd")) { 2101 destroy_workqueue(recv_workqueue); 2102 return -EIO; 2103 } 2104 2105 if (genl_register_family(&nbd_genl_family)) { 2106 unregister_blkdev(NBD_MAJOR, "nbd"); 2107 destroy_workqueue(recv_workqueue); 2108 return -EINVAL; 2109 } 2110 nbd_dbg_init(); 2111 2112 mutex_lock(&nbd_index_mutex); 2113 for (i = 0; i < nbds_max; i++) 2114 nbd_dev_add(i); 2115 mutex_unlock(&nbd_index_mutex); 2116 return 0; 2117 } 2118 2119 static int nbd_exit_cb(int id, void *ptr, void *data) 2120 { 2121 struct list_head *list = (struct list_head *)data; 2122 struct nbd_device *nbd = ptr; 2123 2124 list_add_tail(&nbd->list, list); 2125 return 0; 2126 } 2127 2128 static void __exit nbd_cleanup(void) 2129 { 2130 struct nbd_device *nbd; 2131 LIST_HEAD(del_list); 2132 2133 nbd_dbg_close(); 2134 2135 mutex_lock(&nbd_index_mutex); 2136 idr_for_each(&nbd_index_idr, &nbd_exit_cb, &del_list); 2137 mutex_unlock(&nbd_index_mutex); 2138 2139 while (!list_empty(&del_list)) { 2140 nbd = list_first_entry(&del_list, struct nbd_device, list); 2141 list_del_init(&nbd->list); 2142 if (refcount_read(&nbd->refs) != 1) 2143 printk(KERN_ERR "nbd: possibly leaking a device\n"); 2144 nbd_put(nbd); 2145 } 2146 2147 idr_destroy(&nbd_index_idr); 2148 genl_unregister_family(&nbd_genl_family); 2149 destroy_workqueue(recv_workqueue); 2150 unregister_blkdev(NBD_MAJOR, "nbd"); 2151 } 2152 2153 module_init(nbd_init); 2154 module_exit(nbd_cleanup); 2155 2156 MODULE_DESCRIPTION("Network Block Device"); 2157 MODULE_LICENSE("GPL"); 2158 2159 module_param(nbds_max, int, 0444); 2160 MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)"); 2161 module_param(max_part, int, 0444); 2162 MODULE_PARM_DESC(max_part, "number of partitions per device (default: 16)"); 2163