1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Network block device - make block devices work over TCP
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.
8 * Copyright 1997-2000, 2008 Pavel Machek <pavel@ucw.cz>
9 * Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com>
11 * (part of code stolen from loop.c)
14 #include <linux/major.h>
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>
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>
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>
40 #include <linux/uaccess.h>
41 #include <asm/types.h>
43 #include <linux/nbd.h>
44 #include <linux/nbd-netlink.h>
45 #include <net/genetlink.h>
47 #define CREATE_TRACE_POINTS
48 #include <trace/events/nbd.h>
50 static DEFINE_IDR(nbd_index_idr);
51 static DEFINE_MUTEX(nbd_index_mutex);
52 static int nbd_total_devices = 0;
57 struct request *pending;
64 struct recv_thread_args {
65 struct work_struct work;
66 struct nbd_device *nbd;
70 struct link_dead_args {
71 struct work_struct work;
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
84 #define NBD_DESTROY_ON_DISCONNECT 0
85 #define NBD_DISCONNECT_REQUESTED 1
89 unsigned long runtime_flags;
90 u64 dead_conn_timeout;
92 struct nbd_sock **socks;
94 atomic_t live_connections;
95 wait_queue_head_t conn_wait;
97 atomic_t recv_threads;
98 wait_queue_head_t recv_wq;
101 #if IS_ENABLED(CONFIG_DEBUG_FS)
102 struct dentry *dbg_dir;
107 struct blk_mq_tag_set tag_set;
110 refcount_t config_refs;
112 struct nbd_config *config;
113 struct mutex config_lock;
114 struct gendisk *disk;
115 struct workqueue_struct *recv_workq;
117 struct list_head list;
118 struct task_struct *task_recv;
119 struct task_struct *task_setup;
121 struct completion *destroy_complete;
125 #define NBD_CMD_REQUEUED 1
128 struct nbd_device *nbd;
138 #if IS_ENABLED(CONFIG_DEBUG_FS)
139 static struct dentry *nbd_dbg_dir;
142 #define nbd_name(nbd) ((nbd)->disk->disk_name)
144 #define NBD_MAGIC 0x68797548
146 #define NBD_DEF_BLKSIZE 1024
148 static unsigned int nbds_max = 16;
149 static int max_part = 16;
150 static int part_shift;
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);
160 static inline struct device *nbd_to_dev(struct nbd_device *nbd)
162 return disk_to_dev(nbd->disk);
165 static void nbd_requeue_cmd(struct nbd_cmd *cmd)
167 struct request *req = blk_mq_rq_from_pdu(cmd);
169 if (!test_and_set_bit(NBD_CMD_REQUEUED, &cmd->flags))
170 blk_mq_requeue_request(req, true);
173 #define NBD_COOKIE_BITS 32
175 static u64 nbd_cmd_handle(struct nbd_cmd *cmd)
177 struct request *req = blk_mq_rq_from_pdu(cmd);
178 u32 tag = blk_mq_unique_tag(req);
179 u64 cookie = cmd->cmd_cookie;
181 return (cookie << NBD_COOKIE_BITS) | tag;
184 static u32 nbd_handle_to_tag(u64 handle)
189 static u32 nbd_handle_to_cookie(u64 handle)
191 return (u32)(handle >> NBD_COOKIE_BITS);
194 static const char *nbdcmd_to_ascii(int 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";
206 static ssize_t pid_show(struct device *dev,
207 struct device_attribute *attr, char *buf)
209 struct gendisk *disk = dev_to_disk(dev);
210 struct nbd_device *nbd = (struct nbd_device *)disk->private_data;
212 return sprintf(buf, "%d\n", task_pid_nr(nbd->task_recv));
215 static const struct device_attribute pid_attr = {
216 .attr = { .name = "pid", .mode = 0444},
220 static void nbd_dev_remove(struct nbd_device *nbd)
222 struct gendisk *disk = nbd->disk;
223 struct request_queue *q;
228 blk_cleanup_queue(q);
229 blk_mq_free_tag_set(&nbd->tag_set);
230 disk->private_data = NULL;
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
240 if (test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags) && nbd->destroy_complete)
241 complete(nbd->destroy_complete);
246 static void nbd_put(struct nbd_device *nbd)
248 if (refcount_dec_and_mutex_lock(&nbd->refs,
250 idr_remove(&nbd_index_idr, nbd->index);
252 mutex_unlock(&nbd_index_mutex);
256 static int nbd_disconnected(struct nbd_config *config)
258 return test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags) ||
259 test_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags);
262 static void nbd_mark_nsock_dead(struct nbd_device *nbd, struct nbd_sock *nsock,
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);
269 INIT_WORK(&args->work, nbd_dead_link_work);
270 args->index = nbd->index;
271 queue_work(system_wq, &args->work);
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");
287 nsock->pending = NULL;
291 static void nbd_size_clear(struct nbd_device *nbd)
293 if (nbd->config->bytesize) {
294 set_capacity(nbd->disk, 0);
295 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
299 static int nbd_set_size(struct nbd_device *nbd, loff_t bytesize,
303 blksize = NBD_DEF_BLKSIZE;
304 if (blksize < 512 || blksize > PAGE_SIZE || !is_power_of_2(blksize))
307 nbd->config->bytesize = bytesize;
308 nbd->config->blksize = blksize;
313 if (nbd->config->flags & NBD_FLAG_SEND_TRIM) {
314 nbd->disk->queue->limits.discard_granularity = blksize;
315 nbd->disk->queue->limits.discard_alignment = blksize;
316 blk_queue_max_discard_sectors(nbd->disk->queue, UINT_MAX);
318 blk_queue_logical_block_size(nbd->disk->queue, blksize);
319 blk_queue_physical_block_size(nbd->disk->queue, blksize);
322 set_bit(GD_NEED_PART_SCAN, &nbd->disk->state);
323 if (!set_capacity_and_notify(nbd->disk, bytesize >> 9))
324 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
328 static void nbd_complete_rq(struct request *req)
330 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
332 dev_dbg(nbd_to_dev(cmd->nbd), "request %p: %s\n", req,
333 cmd->status ? "failed" : "done");
335 blk_mq_end_request(req, cmd->status);
339 * Forcibly shutdown the socket causing all listeners to error
341 static void sock_shutdown(struct nbd_device *nbd)
343 struct nbd_config *config = nbd->config;
346 if (config->num_connections == 0)
348 if (test_and_set_bit(NBD_RT_DISCONNECTED, &config->runtime_flags))
351 for (i = 0; i < config->num_connections; i++) {
352 struct nbd_sock *nsock = config->socks[i];
353 mutex_lock(&nsock->tx_lock);
354 nbd_mark_nsock_dead(nbd, nsock, 0);
355 mutex_unlock(&nsock->tx_lock);
357 dev_warn(disk_to_dev(nbd->disk), "shutting down sockets\n");
360 static u32 req_to_nbd_cmd_type(struct request *req)
362 switch (req_op(req)) {
366 return NBD_CMD_FLUSH;
368 return NBD_CMD_WRITE;
376 static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
379 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
380 struct nbd_device *nbd = cmd->nbd;
381 struct nbd_config *config;
383 if (!mutex_trylock(&cmd->lock))
384 return BLK_EH_RESET_TIMER;
386 if (!refcount_inc_not_zero(&nbd->config_refs)) {
387 cmd->status = BLK_STS_TIMEOUT;
388 mutex_unlock(&cmd->lock);
391 config = nbd->config;
393 if (config->num_connections > 1 ||
394 (config->num_connections == 1 && nbd->tag_set.timeout)) {
395 dev_err_ratelimited(nbd_to_dev(nbd),
396 "Connection timed out, retrying (%d/%d alive)\n",
397 atomic_read(&config->live_connections),
398 config->num_connections);
400 * Hooray we have more connections, requeue this IO, the submit
401 * path will put it on a real connection. Or if only one
402 * connection is configured, the submit path will wait util
403 * a new connection is reconfigured or util dead timeout.
406 if (cmd->index < config->num_connections) {
407 struct nbd_sock *nsock =
408 config->socks[cmd->index];
409 mutex_lock(&nsock->tx_lock);
410 /* We can have multiple outstanding requests, so
411 * we don't want to mark the nsock dead if we've
412 * already reconnected with a new socket, so
413 * only mark it dead if its the same socket we
416 if (cmd->cookie == nsock->cookie)
417 nbd_mark_nsock_dead(nbd, nsock, 1);
418 mutex_unlock(&nsock->tx_lock);
420 mutex_unlock(&cmd->lock);
421 nbd_requeue_cmd(cmd);
427 if (!nbd->tag_set.timeout) {
429 * Userspace sets timeout=0 to disable socket disconnection,
430 * so just warn and reset the timer.
432 struct nbd_sock *nsock = config->socks[cmd->index];
434 dev_info(nbd_to_dev(nbd), "Possible stuck request %p: control (%s@%llu,%uB). Runtime %u seconds\n",
435 req, nbdcmd_to_ascii(req_to_nbd_cmd_type(req)),
436 (unsigned long long)blk_rq_pos(req) << 9,
437 blk_rq_bytes(req), (req->timeout / HZ) * cmd->retries);
439 mutex_lock(&nsock->tx_lock);
440 if (cmd->cookie != nsock->cookie) {
441 nbd_requeue_cmd(cmd);
442 mutex_unlock(&nsock->tx_lock);
443 mutex_unlock(&cmd->lock);
447 mutex_unlock(&nsock->tx_lock);
448 mutex_unlock(&cmd->lock);
450 return BLK_EH_RESET_TIMER;
453 dev_err_ratelimited(nbd_to_dev(nbd), "Connection timed out\n");
454 set_bit(NBD_RT_TIMEDOUT, &config->runtime_flags);
455 cmd->status = BLK_STS_IOERR;
456 mutex_unlock(&cmd->lock);
460 blk_mq_complete_request(req);
465 * Send or receive packet.
467 static int sock_xmit(struct nbd_device *nbd, int index, int send,
468 struct iov_iter *iter, int msg_flags, int *sent)
470 struct nbd_config *config = nbd->config;
471 struct socket *sock = config->socks[index]->sock;
474 unsigned int noreclaim_flag;
476 if (unlikely(!sock)) {
477 dev_err_ratelimited(disk_to_dev(nbd->disk),
478 "Attempted %s on closed socket in sock_xmit\n",
479 (send ? "send" : "recv"));
483 msg.msg_iter = *iter;
485 noreclaim_flag = memalloc_noreclaim_save();
487 sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC;
490 msg.msg_control = NULL;
491 msg.msg_controllen = 0;
492 msg.msg_flags = msg_flags | MSG_NOSIGNAL;
495 result = sock_sendmsg(sock, &msg);
497 result = sock_recvmsg(sock, &msg, msg.msg_flags);
501 result = -EPIPE; /* short read */
506 } while (msg_data_left(&msg));
508 memalloc_noreclaim_restore(noreclaim_flag);
514 * Different settings for sk->sk_sndtimeo can result in different return values
515 * if there is a signal pending when we enter sendmsg, because reasons?
517 static inline int was_interrupted(int result)
519 return result == -ERESTARTSYS || result == -EINTR;
522 /* always call with the tx_lock held */
523 static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
525 struct request *req = blk_mq_rq_from_pdu(cmd);
526 struct nbd_config *config = nbd->config;
527 struct nbd_sock *nsock = config->socks[index];
529 struct nbd_request request = {.magic = htonl(NBD_REQUEST_MAGIC)};
530 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
531 struct iov_iter from;
532 unsigned long size = blk_rq_bytes(req);
536 u32 nbd_cmd_flags = 0;
537 int sent = nsock->sent, skip = 0;
539 iov_iter_kvec(&from, WRITE, &iov, 1, sizeof(request));
541 type = req_to_nbd_cmd_type(req);
545 if (rq_data_dir(req) == WRITE &&
546 (config->flags & NBD_FLAG_READ_ONLY)) {
547 dev_err_ratelimited(disk_to_dev(nbd->disk),
548 "Write on read-only\n");
552 if (req->cmd_flags & REQ_FUA)
553 nbd_cmd_flags |= NBD_CMD_FLAG_FUA;
555 /* We did a partial send previously, and we at least sent the whole
556 * request struct, so just go and send the rest of the pages in the
560 if (sent >= sizeof(request)) {
561 skip = sent - sizeof(request);
563 /* initialize handle for tracing purposes */
564 handle = nbd_cmd_handle(cmd);
568 iov_iter_advance(&from, sent);
573 cmd->cookie = nsock->cookie;
575 request.type = htonl(type | nbd_cmd_flags);
576 if (type != NBD_CMD_FLUSH) {
577 request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
578 request.len = htonl(size);
580 handle = nbd_cmd_handle(cmd);
581 memcpy(request.handle, &handle, sizeof(handle));
583 trace_nbd_send_request(&request, nbd->index, blk_mq_rq_from_pdu(cmd));
585 dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n",
586 req, nbdcmd_to_ascii(type),
587 (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req));
588 result = sock_xmit(nbd, index, 1, &from,
589 (type == NBD_CMD_WRITE) ? MSG_MORE : 0, &sent);
590 trace_nbd_header_sent(req, handle);
592 if (was_interrupted(result)) {
593 /* If we havne't sent anything we can just return BUSY,
594 * however if we have sent something we need to make
595 * sure we only allow this req to be sent until we are
599 nsock->pending = req;
602 set_bit(NBD_CMD_REQUEUED, &cmd->flags);
603 return BLK_STS_RESOURCE;
605 dev_err_ratelimited(disk_to_dev(nbd->disk),
606 "Send control failed (result %d)\n", result);
610 if (type != NBD_CMD_WRITE)
615 struct bio *next = bio->bi_next;
616 struct bvec_iter iter;
619 bio_for_each_segment(bvec, bio, iter) {
620 bool is_last = !next && bio_iter_last(bvec, iter);
621 int flags = is_last ? 0 : MSG_MORE;
623 dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n",
625 iov_iter_bvec(&from, WRITE, &bvec, 1, bvec.bv_len);
627 if (skip >= iov_iter_count(&from)) {
628 skip -= iov_iter_count(&from);
631 iov_iter_advance(&from, skip);
634 result = sock_xmit(nbd, index, 1, &from, flags, &sent);
636 if (was_interrupted(result)) {
637 /* We've already sent the header, we
638 * have no choice but to set pending and
641 nsock->pending = req;
643 set_bit(NBD_CMD_REQUEUED, &cmd->flags);
644 return BLK_STS_RESOURCE;
646 dev_err(disk_to_dev(nbd->disk),
647 "Send data failed (result %d)\n",
652 * The completion might already have come in,
653 * so break for the last one instead of letting
654 * the iterator do it. This prevents use-after-free
663 trace_nbd_payload_sent(req, handle);
664 nsock->pending = NULL;
669 /* NULL returned = something went wrong, inform userspace */
670 static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
672 struct nbd_config *config = nbd->config;
674 struct nbd_reply reply;
676 struct request *req = NULL;
680 struct kvec iov = {.iov_base = &reply, .iov_len = sizeof(reply)};
685 iov_iter_kvec(&to, READ, &iov, 1, sizeof(reply));
686 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
688 if (!nbd_disconnected(config))
689 dev_err(disk_to_dev(nbd->disk),
690 "Receive control failed (result %d)\n", result);
691 return ERR_PTR(result);
694 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) {
695 dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n",
696 (unsigned long)ntohl(reply.magic));
697 return ERR_PTR(-EPROTO);
700 memcpy(&handle, reply.handle, sizeof(handle));
701 tag = nbd_handle_to_tag(handle);
702 hwq = blk_mq_unique_tag_to_hwq(tag);
703 if (hwq < nbd->tag_set.nr_hw_queues)
704 req = blk_mq_tag_to_rq(nbd->tag_set.tags[hwq],
705 blk_mq_unique_tag_to_tag(tag));
706 if (!req || !blk_mq_request_started(req)) {
707 dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%d) %p\n",
709 return ERR_PTR(-ENOENT);
711 trace_nbd_header_received(req, handle);
712 cmd = blk_mq_rq_to_pdu(req);
714 mutex_lock(&cmd->lock);
715 if (cmd->cmd_cookie != nbd_handle_to_cookie(handle)) {
716 dev_err(disk_to_dev(nbd->disk), "Double reply on req %p, cmd_cookie %u, handle cookie %u\n",
717 req, cmd->cmd_cookie, nbd_handle_to_cookie(handle));
721 if (cmd->status != BLK_STS_OK) {
722 dev_err(disk_to_dev(nbd->disk), "Command already handled %p\n",
727 if (test_bit(NBD_CMD_REQUEUED, &cmd->flags)) {
728 dev_err(disk_to_dev(nbd->disk), "Raced with timeout on req %p\n",
733 if (ntohl(reply.error)) {
734 dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n",
736 cmd->status = BLK_STS_IOERR;
740 dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", req);
741 if (rq_data_dir(req) != WRITE) {
742 struct req_iterator iter;
745 rq_for_each_segment(bvec, req, iter) {
746 iov_iter_bvec(&to, READ, &bvec, 1, bvec.bv_len);
747 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
749 dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
752 * If we've disconnected, we need to make sure we
753 * complete this request, otherwise error out
754 * and let the timeout stuff handle resubmitting
755 * this request onto another connection.
757 if (nbd_disconnected(config)) {
758 cmd->status = BLK_STS_IOERR;
764 dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n",
769 trace_nbd_payload_received(req, handle);
770 mutex_unlock(&cmd->lock);
771 return ret ? ERR_PTR(ret) : cmd;
774 static void recv_work(struct work_struct *work)
776 struct recv_thread_args *args = container_of(work,
777 struct recv_thread_args,
779 struct nbd_device *nbd = args->nbd;
780 struct nbd_config *config = nbd->config;
785 cmd = nbd_read_stat(nbd, args->index);
787 struct nbd_sock *nsock = config->socks[args->index];
789 mutex_lock(&nsock->tx_lock);
790 nbd_mark_nsock_dead(nbd, nsock, 1);
791 mutex_unlock(&nsock->tx_lock);
795 rq = blk_mq_rq_from_pdu(cmd);
796 if (likely(!blk_should_fake_timeout(rq->q)))
797 blk_mq_complete_request(rq);
800 atomic_dec(&config->recv_threads);
801 wake_up(&config->recv_wq);
805 static bool nbd_clear_req(struct request *req, void *data, bool reserved)
807 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
809 mutex_lock(&cmd->lock);
810 cmd->status = BLK_STS_IOERR;
811 mutex_unlock(&cmd->lock);
813 blk_mq_complete_request(req);
817 static void nbd_clear_que(struct nbd_device *nbd)
819 blk_mq_quiesce_queue(nbd->disk->queue);
820 blk_mq_tagset_busy_iter(&nbd->tag_set, nbd_clear_req, NULL);
821 blk_mq_unquiesce_queue(nbd->disk->queue);
822 dev_dbg(disk_to_dev(nbd->disk), "queue cleared\n");
825 static int find_fallback(struct nbd_device *nbd, int index)
827 struct nbd_config *config = nbd->config;
829 struct nbd_sock *nsock = config->socks[index];
830 int fallback = nsock->fallback_index;
832 if (test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags))
835 if (config->num_connections <= 1) {
836 dev_err_ratelimited(disk_to_dev(nbd->disk),
837 "Dead connection, failed to find a fallback\n");
841 if (fallback >= 0 && fallback < config->num_connections &&
842 !config->socks[fallback]->dead)
845 if (nsock->fallback_index < 0 ||
846 nsock->fallback_index >= config->num_connections ||
847 config->socks[nsock->fallback_index]->dead) {
849 for (i = 0; i < config->num_connections; i++) {
852 if (!config->socks[i]->dead) {
857 nsock->fallback_index = new_index;
859 dev_err_ratelimited(disk_to_dev(nbd->disk),
860 "Dead connection, failed to find a fallback\n");
864 new_index = nsock->fallback_index;
868 static int wait_for_reconnect(struct nbd_device *nbd)
870 struct nbd_config *config = nbd->config;
871 if (!config->dead_conn_timeout)
873 if (test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags))
875 return wait_event_timeout(config->conn_wait,
876 atomic_read(&config->live_connections) > 0,
877 config->dead_conn_timeout) > 0;
880 static int nbd_handle_cmd(struct nbd_cmd *cmd, int index)
882 struct request *req = blk_mq_rq_from_pdu(cmd);
883 struct nbd_device *nbd = cmd->nbd;
884 struct nbd_config *config;
885 struct nbd_sock *nsock;
888 if (!refcount_inc_not_zero(&nbd->config_refs)) {
889 dev_err_ratelimited(disk_to_dev(nbd->disk),
890 "Socks array is empty\n");
891 blk_mq_start_request(req);
894 config = nbd->config;
896 if (index >= config->num_connections) {
897 dev_err_ratelimited(disk_to_dev(nbd->disk),
898 "Attempted send on invalid socket\n");
900 blk_mq_start_request(req);
903 cmd->status = BLK_STS_OK;
905 nsock = config->socks[index];
906 mutex_lock(&nsock->tx_lock);
908 int old_index = index;
909 index = find_fallback(nbd, index);
910 mutex_unlock(&nsock->tx_lock);
912 if (wait_for_reconnect(nbd)) {
916 /* All the sockets should already be down at this point,
917 * we just want to make sure that DISCONNECTED is set so
918 * any requests that come in that were queue'ed waiting
919 * for the reconnect timer don't trigger the timer again
920 * and instead just error out.
924 blk_mq_start_request(req);
930 /* Handle the case that we have a pending request that was partially
931 * transmitted that _has_ to be serviced first. We need to call requeue
932 * here so that it gets put _after_ the request that is already on the
935 blk_mq_start_request(req);
936 if (unlikely(nsock->pending && nsock->pending != req)) {
937 nbd_requeue_cmd(cmd);
942 * Some failures are related to the link going down, so anything that
943 * returns EAGAIN can be retried on a different socket.
945 ret = nbd_send_cmd(nbd, cmd, index);
946 if (ret == -EAGAIN) {
947 dev_err_ratelimited(disk_to_dev(nbd->disk),
948 "Request send failed, requeueing\n");
949 nbd_mark_nsock_dead(nbd, nsock, 1);
950 nbd_requeue_cmd(cmd);
954 mutex_unlock(&nsock->tx_lock);
959 static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
960 const struct blk_mq_queue_data *bd)
962 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
966 * Since we look at the bio's to send the request over the network we
967 * need to make sure the completion work doesn't mark this request done
968 * before we are done doing our send. This keeps us from dereferencing
969 * freed data if we have particularly fast completions (ie we get the
970 * completion before we exit sock_xmit on the last bvec) or in the case
971 * that the server is misbehaving (or there was an error) before we're
972 * done sending everything over the wire.
974 mutex_lock(&cmd->lock);
975 clear_bit(NBD_CMD_REQUEUED, &cmd->flags);
977 /* We can be called directly from the user space process, which means we
978 * could possibly have signals pending so our sendmsg will fail. In
979 * this case we need to return that we are busy, otherwise error out as
982 ret = nbd_handle_cmd(cmd, hctx->queue_num);
987 mutex_unlock(&cmd->lock);
992 static struct socket *nbd_get_socket(struct nbd_device *nbd, unsigned long fd,
998 sock = sockfd_lookup(fd, err);
1002 if (sock->ops->shutdown == sock_no_shutdown) {
1003 dev_err(disk_to_dev(nbd->disk), "Unsupported socket: shutdown callout must be supported.\n");
1012 static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
1015 struct nbd_config *config = nbd->config;
1016 struct socket *sock;
1017 struct nbd_sock **socks;
1018 struct nbd_sock *nsock;
1021 sock = nbd_get_socket(nbd, arg, &err);
1026 * We need to make sure we don't get any errant requests while we're
1027 * reallocating the ->socks array.
1029 blk_mq_freeze_queue(nbd->disk->queue);
1031 if (!netlink && !nbd->task_setup &&
1032 !test_bit(NBD_RT_BOUND, &config->runtime_flags))
1033 nbd->task_setup = current;
1036 (nbd->task_setup != current ||
1037 test_bit(NBD_RT_BOUND, &config->runtime_flags))) {
1038 dev_err(disk_to_dev(nbd->disk),
1039 "Device being setup by another task");
1044 nsock = kzalloc(sizeof(*nsock), GFP_KERNEL);
1050 socks = krealloc(config->socks, (config->num_connections + 1) *
1051 sizeof(struct nbd_sock *), GFP_KERNEL);
1058 config->socks = socks;
1060 nsock->fallback_index = -1;
1061 nsock->dead = false;
1062 mutex_init(&nsock->tx_lock);
1064 nsock->pending = NULL;
1067 socks[config->num_connections++] = nsock;
1068 atomic_inc(&config->live_connections);
1069 blk_mq_unfreeze_queue(nbd->disk->queue);
1074 blk_mq_unfreeze_queue(nbd->disk->queue);
1079 static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg)
1081 struct nbd_config *config = nbd->config;
1082 struct socket *sock, *old;
1083 struct recv_thread_args *args;
1087 sock = nbd_get_socket(nbd, arg, &err);
1091 args = kzalloc(sizeof(*args), GFP_KERNEL);
1097 for (i = 0; i < config->num_connections; i++) {
1098 struct nbd_sock *nsock = config->socks[i];
1103 mutex_lock(&nsock->tx_lock);
1105 mutex_unlock(&nsock->tx_lock);
1108 sk_set_memalloc(sock->sk);
1109 if (nbd->tag_set.timeout)
1110 sock->sk->sk_sndtimeo = nbd->tag_set.timeout;
1111 atomic_inc(&config->recv_threads);
1112 refcount_inc(&nbd->config_refs);
1114 nsock->fallback_index = -1;
1116 nsock->dead = false;
1117 INIT_WORK(&args->work, recv_work);
1121 mutex_unlock(&nsock->tx_lock);
1124 clear_bit(NBD_RT_DISCONNECTED, &config->runtime_flags);
1126 /* We take the tx_mutex in an error path in the recv_work, so we
1127 * need to queue_work outside of the tx_mutex.
1129 queue_work(nbd->recv_workq, &args->work);
1131 atomic_inc(&config->live_connections);
1132 wake_up(&config->conn_wait);
1140 static void nbd_bdev_reset(struct block_device *bdev)
1142 if (bdev->bd_openers > 1)
1144 set_capacity(bdev->bd_disk, 0);
1147 static void nbd_parse_flags(struct nbd_device *nbd)
1149 struct nbd_config *config = nbd->config;
1150 if (config->flags & NBD_FLAG_READ_ONLY)
1151 set_disk_ro(nbd->disk, true);
1153 set_disk_ro(nbd->disk, false);
1154 if (config->flags & NBD_FLAG_SEND_TRIM)
1155 blk_queue_flag_set(QUEUE_FLAG_DISCARD, nbd->disk->queue);
1156 if (config->flags & NBD_FLAG_SEND_FLUSH) {
1157 if (config->flags & NBD_FLAG_SEND_FUA)
1158 blk_queue_write_cache(nbd->disk->queue, true, true);
1160 blk_queue_write_cache(nbd->disk->queue, true, false);
1163 blk_queue_write_cache(nbd->disk->queue, false, false);
1166 static void send_disconnects(struct nbd_device *nbd)
1168 struct nbd_config *config = nbd->config;
1169 struct nbd_request request = {
1170 .magic = htonl(NBD_REQUEST_MAGIC),
1171 .type = htonl(NBD_CMD_DISC),
1173 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
1174 struct iov_iter from;
1177 for (i = 0; i < config->num_connections; i++) {
1178 struct nbd_sock *nsock = config->socks[i];
1180 iov_iter_kvec(&from, WRITE, &iov, 1, sizeof(request));
1181 mutex_lock(&nsock->tx_lock);
1182 ret = sock_xmit(nbd, i, 1, &from, 0, NULL);
1184 dev_err(disk_to_dev(nbd->disk),
1185 "Send disconnect failed %d\n", ret);
1186 mutex_unlock(&nsock->tx_lock);
1190 static int nbd_disconnect(struct nbd_device *nbd)
1192 struct nbd_config *config = nbd->config;
1194 dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
1195 set_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags);
1196 set_bit(NBD_DISCONNECT_REQUESTED, &nbd->flags);
1197 send_disconnects(nbd);
1201 static void nbd_clear_sock(struct nbd_device *nbd)
1205 nbd->task_setup = NULL;
1208 static void nbd_config_put(struct nbd_device *nbd)
1210 if (refcount_dec_and_mutex_lock(&nbd->config_refs,
1211 &nbd->config_lock)) {
1212 struct nbd_config *config = nbd->config;
1213 nbd_dev_dbg_close(nbd);
1214 nbd_size_clear(nbd);
1215 if (test_and_clear_bit(NBD_RT_HAS_PID_FILE,
1216 &config->runtime_flags))
1217 device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
1218 nbd->task_recv = NULL;
1219 nbd_clear_sock(nbd);
1220 if (config->num_connections) {
1222 for (i = 0; i < config->num_connections; i++) {
1223 sockfd_put(config->socks[i]->sock);
1224 kfree(config->socks[i]);
1226 kfree(config->socks);
1231 if (nbd->recv_workq)
1232 destroy_workqueue(nbd->recv_workq);
1233 nbd->recv_workq = NULL;
1235 nbd->tag_set.timeout = 0;
1236 nbd->disk->queue->limits.discard_granularity = 0;
1237 nbd->disk->queue->limits.discard_alignment = 0;
1238 blk_queue_max_discard_sectors(nbd->disk->queue, UINT_MAX);
1239 blk_queue_flag_clear(QUEUE_FLAG_DISCARD, nbd->disk->queue);
1241 mutex_unlock(&nbd->config_lock);
1243 module_put(THIS_MODULE);
1247 static int nbd_start_device(struct nbd_device *nbd)
1249 struct nbd_config *config = nbd->config;
1250 int num_connections = config->num_connections;
1257 if (num_connections > 1 &&
1258 !(config->flags & NBD_FLAG_CAN_MULTI_CONN)) {
1259 dev_err(disk_to_dev(nbd->disk), "server does not support multiple connections per device.\n");
1263 nbd->recv_workq = alloc_workqueue("knbd%d-recv",
1264 WQ_MEM_RECLAIM | WQ_HIGHPRI |
1265 WQ_UNBOUND, 0, nbd->index);
1266 if (!nbd->recv_workq) {
1267 dev_err(disk_to_dev(nbd->disk), "Could not allocate knbd recv work queue.\n");
1271 blk_mq_update_nr_hw_queues(&nbd->tag_set, config->num_connections);
1272 nbd->task_recv = current;
1274 nbd_parse_flags(nbd);
1276 error = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
1278 dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n");
1281 set_bit(NBD_RT_HAS_PID_FILE, &config->runtime_flags);
1283 nbd_dev_dbg_init(nbd);
1284 for (i = 0; i < num_connections; i++) {
1285 struct recv_thread_args *args;
1287 args = kzalloc(sizeof(*args), GFP_KERNEL);
1291 * If num_connections is m (2 < m),
1292 * and NO.1 ~ NO.n(1 < n < m) kzallocs are successful.
1293 * But NO.(n + 1) failed. We still have n recv threads.
1294 * So, add flush_workqueue here to prevent recv threads
1295 * dropping the last config_refs and trying to destroy
1296 * the workqueue from inside the workqueue.
1299 flush_workqueue(nbd->recv_workq);
1302 sk_set_memalloc(config->socks[i]->sock->sk);
1303 if (nbd->tag_set.timeout)
1304 config->socks[i]->sock->sk->sk_sndtimeo =
1305 nbd->tag_set.timeout;
1306 atomic_inc(&config->recv_threads);
1307 refcount_inc(&nbd->config_refs);
1308 INIT_WORK(&args->work, recv_work);
1311 queue_work(nbd->recv_workq, &args->work);
1313 return nbd_set_size(nbd, config->bytesize, config->blksize);
1316 static int nbd_start_device_ioctl(struct nbd_device *nbd, struct block_device *bdev)
1318 struct nbd_config *config = nbd->config;
1321 ret = nbd_start_device(nbd);
1326 set_bit(GD_NEED_PART_SCAN, &nbd->disk->state);
1327 mutex_unlock(&nbd->config_lock);
1328 ret = wait_event_interruptible(config->recv_wq,
1329 atomic_read(&config->recv_threads) == 0);
1332 flush_workqueue(nbd->recv_workq);
1334 mutex_lock(&nbd->config_lock);
1335 nbd_bdev_reset(bdev);
1336 /* user requested, ignore socket errors */
1337 if (test_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags))
1339 if (test_bit(NBD_RT_TIMEDOUT, &config->runtime_flags))
1344 static void nbd_clear_sock_ioctl(struct nbd_device *nbd,
1345 struct block_device *bdev)
1348 __invalidate_device(bdev, true);
1349 nbd_bdev_reset(bdev);
1350 if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF,
1351 &nbd->config->runtime_flags))
1352 nbd_config_put(nbd);
1355 static void nbd_set_cmd_timeout(struct nbd_device *nbd, u64 timeout)
1357 nbd->tag_set.timeout = timeout * HZ;
1359 blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ);
1361 blk_queue_rq_timeout(nbd->disk->queue, 30 * HZ);
1364 /* Must be called with config_lock held */
1365 static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
1366 unsigned int cmd, unsigned long arg)
1368 struct nbd_config *config = nbd->config;
1371 case NBD_DISCONNECT:
1372 return nbd_disconnect(nbd);
1373 case NBD_CLEAR_SOCK:
1374 nbd_clear_sock_ioctl(nbd, bdev);
1377 return nbd_add_socket(nbd, arg, false);
1378 case NBD_SET_BLKSIZE:
1379 return nbd_set_size(nbd, config->bytesize, arg);
1381 return nbd_set_size(nbd, arg, config->blksize);
1382 case NBD_SET_SIZE_BLOCKS:
1383 return nbd_set_size(nbd, arg * config->blksize,
1385 case NBD_SET_TIMEOUT:
1386 nbd_set_cmd_timeout(nbd, arg);
1390 config->flags = arg;
1393 return nbd_start_device_ioctl(nbd, bdev);
1396 * This is for compatibility only. The queue is always cleared
1397 * by NBD_DO_IT or NBD_CLEAR_SOCK.
1400 case NBD_PRINT_DEBUG:
1402 * For compatibility only, we no longer keep a list of
1403 * outstanding requests.
1410 static int nbd_ioctl(struct block_device *bdev, fmode_t mode,
1411 unsigned int cmd, unsigned long arg)
1413 struct nbd_device *nbd = bdev->bd_disk->private_data;
1414 struct nbd_config *config = nbd->config;
1415 int error = -EINVAL;
1417 if (!capable(CAP_SYS_ADMIN))
1420 /* The block layer will pass back some non-nbd ioctls in case we have
1421 * special handling for them, but we don't so just return an error.
1423 if (_IOC_TYPE(cmd) != 0xab)
1426 mutex_lock(&nbd->config_lock);
1428 /* Don't allow ioctl operations on a nbd device that was created with
1429 * netlink, unless it's DISCONNECT or CLEAR_SOCK, which are fine.
1431 if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) ||
1432 (cmd == NBD_DISCONNECT || cmd == NBD_CLEAR_SOCK))
1433 error = __nbd_ioctl(bdev, nbd, cmd, arg);
1435 dev_err(nbd_to_dev(nbd), "Cannot use ioctl interface on a netlink controlled device.\n");
1436 mutex_unlock(&nbd->config_lock);
1440 static struct nbd_config *nbd_alloc_config(void)
1442 struct nbd_config *config;
1444 config = kzalloc(sizeof(struct nbd_config), GFP_NOFS);
1447 atomic_set(&config->recv_threads, 0);
1448 init_waitqueue_head(&config->recv_wq);
1449 init_waitqueue_head(&config->conn_wait);
1450 config->blksize = NBD_DEF_BLKSIZE;
1451 atomic_set(&config->live_connections, 0);
1452 try_module_get(THIS_MODULE);
1456 static int nbd_open(struct block_device *bdev, fmode_t mode)
1458 struct nbd_device *nbd;
1461 mutex_lock(&nbd_index_mutex);
1462 nbd = bdev->bd_disk->private_data;
1467 if (!refcount_inc_not_zero(&nbd->refs)) {
1471 if (!refcount_inc_not_zero(&nbd->config_refs)) {
1472 struct nbd_config *config;
1474 mutex_lock(&nbd->config_lock);
1475 if (refcount_inc_not_zero(&nbd->config_refs)) {
1476 mutex_unlock(&nbd->config_lock);
1479 config = nbd->config = nbd_alloc_config();
1482 mutex_unlock(&nbd->config_lock);
1485 refcount_set(&nbd->config_refs, 1);
1486 refcount_inc(&nbd->refs);
1487 mutex_unlock(&nbd->config_lock);
1489 set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
1490 } else if (nbd_disconnected(nbd->config)) {
1492 set_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
1495 mutex_unlock(&nbd_index_mutex);
1499 static void nbd_release(struct gendisk *disk, fmode_t mode)
1501 struct nbd_device *nbd = disk->private_data;
1503 if (test_bit(NBD_RT_DISCONNECT_ON_CLOSE, &nbd->config->runtime_flags) &&
1504 disk->part0->bd_openers == 0)
1505 nbd_disconnect_and_put(nbd);
1507 nbd_config_put(nbd);
1511 static const struct block_device_operations nbd_fops =
1513 .owner = THIS_MODULE,
1515 .release = nbd_release,
1517 .compat_ioctl = nbd_ioctl,
1520 #if IS_ENABLED(CONFIG_DEBUG_FS)
1522 static int nbd_dbg_tasks_show(struct seq_file *s, void *unused)
1524 struct nbd_device *nbd = s->private;
1527 seq_printf(s, "recv: %d\n", task_pid_nr(nbd->task_recv));
1532 DEFINE_SHOW_ATTRIBUTE(nbd_dbg_tasks);
1534 static int nbd_dbg_flags_show(struct seq_file *s, void *unused)
1536 struct nbd_device *nbd = s->private;
1537 u32 flags = nbd->config->flags;
1539 seq_printf(s, "Hex: 0x%08x\n\n", flags);
1541 seq_puts(s, "Known flags:\n");
1543 if (flags & NBD_FLAG_HAS_FLAGS)
1544 seq_puts(s, "NBD_FLAG_HAS_FLAGS\n");
1545 if (flags & NBD_FLAG_READ_ONLY)
1546 seq_puts(s, "NBD_FLAG_READ_ONLY\n");
1547 if (flags & NBD_FLAG_SEND_FLUSH)
1548 seq_puts(s, "NBD_FLAG_SEND_FLUSH\n");
1549 if (flags & NBD_FLAG_SEND_FUA)
1550 seq_puts(s, "NBD_FLAG_SEND_FUA\n");
1551 if (flags & NBD_FLAG_SEND_TRIM)
1552 seq_puts(s, "NBD_FLAG_SEND_TRIM\n");
1557 DEFINE_SHOW_ATTRIBUTE(nbd_dbg_flags);
1559 static int nbd_dev_dbg_init(struct nbd_device *nbd)
1562 struct nbd_config *config = nbd->config;
1567 dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir);
1569 dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s'\n",
1573 config->dbg_dir = dir;
1575 debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_fops);
1576 debugfs_create_u64("size_bytes", 0444, dir, &config->bytesize);
1577 debugfs_create_u32("timeout", 0444, dir, &nbd->tag_set.timeout);
1578 debugfs_create_u64("blocksize", 0444, dir, &config->blksize);
1579 debugfs_create_file("flags", 0444, dir, nbd, &nbd_dbg_flags_fops);
1584 static void nbd_dev_dbg_close(struct nbd_device *nbd)
1586 debugfs_remove_recursive(nbd->config->dbg_dir);
1589 static int nbd_dbg_init(void)
1591 struct dentry *dbg_dir;
1593 dbg_dir = debugfs_create_dir("nbd", NULL);
1597 nbd_dbg_dir = dbg_dir;
1602 static void nbd_dbg_close(void)
1604 debugfs_remove_recursive(nbd_dbg_dir);
1607 #else /* IS_ENABLED(CONFIG_DEBUG_FS) */
1609 static int nbd_dev_dbg_init(struct nbd_device *nbd)
1614 static void nbd_dev_dbg_close(struct nbd_device *nbd)
1618 static int nbd_dbg_init(void)
1623 static void nbd_dbg_close(void)
1629 static int nbd_init_request(struct blk_mq_tag_set *set, struct request *rq,
1630 unsigned int hctx_idx, unsigned int numa_node)
1632 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq);
1633 cmd->nbd = set->driver_data;
1635 mutex_init(&cmd->lock);
1639 static const struct blk_mq_ops nbd_mq_ops = {
1640 .queue_rq = nbd_queue_rq,
1641 .complete = nbd_complete_rq,
1642 .init_request = nbd_init_request,
1643 .timeout = nbd_xmit_timeout,
1646 static int nbd_dev_add(int index)
1648 struct nbd_device *nbd;
1649 struct gendisk *disk;
1650 struct request_queue *q;
1653 nbd = kzalloc(sizeof(struct nbd_device), GFP_KERNEL);
1657 disk = alloc_disk(1 << part_shift);
1662 err = idr_alloc(&nbd_index_idr, nbd, index, index + 1,
1667 err = idr_alloc(&nbd_index_idr, nbd, 0, 0, GFP_KERNEL);
1676 nbd->tag_set.ops = &nbd_mq_ops;
1677 nbd->tag_set.nr_hw_queues = 1;
1678 nbd->tag_set.queue_depth = 128;
1679 nbd->tag_set.numa_node = NUMA_NO_NODE;
1680 nbd->tag_set.cmd_size = sizeof(struct nbd_cmd);
1681 nbd->tag_set.flags = BLK_MQ_F_SHOULD_MERGE |
1683 nbd->tag_set.driver_data = nbd;
1684 nbd->destroy_complete = NULL;
1686 err = blk_mq_alloc_tag_set(&nbd->tag_set);
1690 q = blk_mq_init_queue(&nbd->tag_set);
1698 * Tell the block layer that we are not a rotational device
1700 blk_queue_flag_set(QUEUE_FLAG_NONROT, disk->queue);
1701 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, disk->queue);
1702 disk->queue->limits.discard_granularity = 0;
1703 disk->queue->limits.discard_alignment = 0;
1704 blk_queue_max_discard_sectors(disk->queue, 0);
1705 blk_queue_max_segment_size(disk->queue, UINT_MAX);
1706 blk_queue_max_segments(disk->queue, USHRT_MAX);
1707 blk_queue_max_hw_sectors(disk->queue, 65536);
1708 disk->queue->limits.max_sectors = 256;
1710 mutex_init(&nbd->config_lock);
1711 refcount_set(&nbd->config_refs, 0);
1712 refcount_set(&nbd->refs, 1);
1713 INIT_LIST_HEAD(&nbd->list);
1714 disk->major = NBD_MAJOR;
1715 disk->first_minor = index << part_shift;
1716 disk->fops = &nbd_fops;
1717 disk->private_data = nbd;
1718 sprintf(disk->disk_name, "nbd%d", index);
1720 nbd_total_devices++;
1724 blk_mq_free_tag_set(&nbd->tag_set);
1726 idr_remove(&nbd_index_idr, index);
1735 static int find_free_cb(int id, void *ptr, void *data)
1737 struct nbd_device *nbd = ptr;
1738 struct nbd_device **found = data;
1740 if (!refcount_read(&nbd->config_refs)) {
1747 /* Netlink interface. */
1748 static const struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = {
1749 [NBD_ATTR_INDEX] = { .type = NLA_U32 },
1750 [NBD_ATTR_SIZE_BYTES] = { .type = NLA_U64 },
1751 [NBD_ATTR_BLOCK_SIZE_BYTES] = { .type = NLA_U64 },
1752 [NBD_ATTR_TIMEOUT] = { .type = NLA_U64 },
1753 [NBD_ATTR_SERVER_FLAGS] = { .type = NLA_U64 },
1754 [NBD_ATTR_CLIENT_FLAGS] = { .type = NLA_U64 },
1755 [NBD_ATTR_SOCKETS] = { .type = NLA_NESTED},
1756 [NBD_ATTR_DEAD_CONN_TIMEOUT] = { .type = NLA_U64 },
1757 [NBD_ATTR_DEVICE_LIST] = { .type = NLA_NESTED},
1760 static const struct nla_policy nbd_sock_policy[NBD_SOCK_MAX + 1] = {
1761 [NBD_SOCK_FD] = { .type = NLA_U32 },
1764 /* We don't use this right now since we don't parse the incoming list, but we
1765 * still want it here so userspace knows what to expect.
1767 static const struct nla_policy __attribute__((unused))
1768 nbd_device_policy[NBD_DEVICE_ATTR_MAX + 1] = {
1769 [NBD_DEVICE_INDEX] = { .type = NLA_U32 },
1770 [NBD_DEVICE_CONNECTED] = { .type = NLA_U8 },
1773 static int nbd_genl_size_set(struct genl_info *info, struct nbd_device *nbd)
1775 struct nbd_config *config = nbd->config;
1776 u64 bsize = config->blksize;
1777 u64 bytes = config->bytesize;
1779 if (info->attrs[NBD_ATTR_SIZE_BYTES])
1780 bytes = nla_get_u64(info->attrs[NBD_ATTR_SIZE_BYTES]);
1782 if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES])
1783 bsize = nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]);
1785 if (bytes != config->bytesize || bsize != config->blksize)
1786 return nbd_set_size(nbd, bytes, bsize);
1790 static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
1792 DECLARE_COMPLETION_ONSTACK(destroy_complete);
1793 struct nbd_device *nbd = NULL;
1794 struct nbd_config *config;
1797 bool put_dev = false;
1799 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1802 if (info->attrs[NBD_ATTR_INDEX])
1803 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1804 if (!info->attrs[NBD_ATTR_SOCKETS]) {
1805 printk(KERN_ERR "nbd: must specify at least one socket\n");
1808 if (!info->attrs[NBD_ATTR_SIZE_BYTES]) {
1809 printk(KERN_ERR "nbd: must specify a size in bytes for the device\n");
1813 mutex_lock(&nbd_index_mutex);
1815 ret = idr_for_each(&nbd_index_idr, &find_free_cb, &nbd);
1818 new_index = nbd_dev_add(-1);
1819 if (new_index < 0) {
1820 mutex_unlock(&nbd_index_mutex);
1821 printk(KERN_ERR "nbd: failed to add new device\n");
1824 nbd = idr_find(&nbd_index_idr, new_index);
1827 nbd = idr_find(&nbd_index_idr, index);
1829 ret = nbd_dev_add(index);
1831 mutex_unlock(&nbd_index_mutex);
1832 printk(KERN_ERR "nbd: failed to add new device\n");
1835 nbd = idr_find(&nbd_index_idr, index);
1839 printk(KERN_ERR "nbd: couldn't find device at index %d\n",
1841 mutex_unlock(&nbd_index_mutex);
1845 if (test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags) &&
1846 test_bit(NBD_DISCONNECT_REQUESTED, &nbd->flags)) {
1847 nbd->destroy_complete = &destroy_complete;
1848 mutex_unlock(&nbd_index_mutex);
1850 /* Wait untill the the nbd stuff is totally destroyed */
1851 wait_for_completion(&destroy_complete);
1855 if (!refcount_inc_not_zero(&nbd->refs)) {
1856 mutex_unlock(&nbd_index_mutex);
1859 printk(KERN_ERR "nbd: device at index %d is going down\n",
1863 mutex_unlock(&nbd_index_mutex);
1865 mutex_lock(&nbd->config_lock);
1866 if (refcount_read(&nbd->config_refs)) {
1867 mutex_unlock(&nbd->config_lock);
1871 printk(KERN_ERR "nbd: nbd%d already in use\n", index);
1874 if (WARN_ON(nbd->config)) {
1875 mutex_unlock(&nbd->config_lock);
1879 config = nbd->config = nbd_alloc_config();
1881 mutex_unlock(&nbd->config_lock);
1883 printk(KERN_ERR "nbd: couldn't allocate config\n");
1886 refcount_set(&nbd->config_refs, 1);
1887 set_bit(NBD_RT_BOUND, &config->runtime_flags);
1889 ret = nbd_genl_size_set(info, nbd);
1893 if (info->attrs[NBD_ATTR_TIMEOUT])
1894 nbd_set_cmd_timeout(nbd,
1895 nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]));
1896 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
1897 config->dead_conn_timeout =
1898 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
1899 config->dead_conn_timeout *= HZ;
1901 if (info->attrs[NBD_ATTR_SERVER_FLAGS])
1903 nla_get_u64(info->attrs[NBD_ATTR_SERVER_FLAGS]);
1904 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
1905 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
1906 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
1907 set_bit(NBD_RT_DESTROY_ON_DISCONNECT,
1908 &config->runtime_flags);
1909 set_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags);
1912 clear_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags);
1914 if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {
1915 set_bit(NBD_RT_DISCONNECT_ON_CLOSE,
1916 &config->runtime_flags);
1920 if (info->attrs[NBD_ATTR_SOCKETS]) {
1921 struct nlattr *attr;
1924 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
1926 struct nlattr *socks[NBD_SOCK_MAX+1];
1928 if (nla_type(attr) != NBD_SOCK_ITEM) {
1929 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");
1933 ret = nla_parse_nested_deprecated(socks, NBD_SOCK_MAX,
1938 printk(KERN_ERR "nbd: error processing sock list\n");
1942 if (!socks[NBD_SOCK_FD])
1944 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
1945 ret = nbd_add_socket(nbd, fd, true);
1950 ret = nbd_start_device(nbd);
1952 mutex_unlock(&nbd->config_lock);
1954 set_bit(NBD_RT_HAS_CONFIG_REF, &config->runtime_flags);
1955 refcount_inc(&nbd->config_refs);
1956 nbd_connect_reply(info, nbd->index);
1958 nbd_config_put(nbd);
1964 static void nbd_disconnect_and_put(struct nbd_device *nbd)
1966 mutex_lock(&nbd->config_lock);
1967 nbd_disconnect(nbd);
1968 nbd_clear_sock(nbd);
1969 mutex_unlock(&nbd->config_lock);
1971 * Make sure recv thread has finished, so it does not drop the last
1972 * config ref and try to destroy the workqueue from inside the work
1975 flush_workqueue(nbd->recv_workq);
1976 if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF,
1977 &nbd->config->runtime_flags))
1978 nbd_config_put(nbd);
1981 static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info)
1983 struct nbd_device *nbd;
1986 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1989 if (!info->attrs[NBD_ATTR_INDEX]) {
1990 printk(KERN_ERR "nbd: must specify an index to disconnect\n");
1993 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1994 mutex_lock(&nbd_index_mutex);
1995 nbd = idr_find(&nbd_index_idr, index);
1997 mutex_unlock(&nbd_index_mutex);
1998 printk(KERN_ERR "nbd: couldn't find device at index %d\n",
2002 if (!refcount_inc_not_zero(&nbd->refs)) {
2003 mutex_unlock(&nbd_index_mutex);
2004 printk(KERN_ERR "nbd: device at index %d is going down\n",
2008 mutex_unlock(&nbd_index_mutex);
2009 if (!refcount_inc_not_zero(&nbd->config_refs)) {
2013 nbd_disconnect_and_put(nbd);
2014 nbd_config_put(nbd);
2019 static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info)
2021 struct nbd_device *nbd = NULL;
2022 struct nbd_config *config;
2025 bool put_dev = false;
2027 if (!netlink_capable(skb, CAP_SYS_ADMIN))
2030 if (!info->attrs[NBD_ATTR_INDEX]) {
2031 printk(KERN_ERR "nbd: must specify a device to reconfigure\n");
2034 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2035 mutex_lock(&nbd_index_mutex);
2036 nbd = idr_find(&nbd_index_idr, index);
2038 mutex_unlock(&nbd_index_mutex);
2039 printk(KERN_ERR "nbd: couldn't find a device at index %d\n",
2043 if (!refcount_inc_not_zero(&nbd->refs)) {
2044 mutex_unlock(&nbd_index_mutex);
2045 printk(KERN_ERR "nbd: device at index %d is going down\n",
2049 mutex_unlock(&nbd_index_mutex);
2051 if (!refcount_inc_not_zero(&nbd->config_refs)) {
2052 dev_err(nbd_to_dev(nbd),
2053 "not configured, cannot reconfigure\n");
2058 mutex_lock(&nbd->config_lock);
2059 config = nbd->config;
2060 if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) ||
2062 dev_err(nbd_to_dev(nbd),
2063 "not configured, cannot reconfigure\n");
2068 ret = nbd_genl_size_set(info, nbd);
2072 if (info->attrs[NBD_ATTR_TIMEOUT])
2073 nbd_set_cmd_timeout(nbd,
2074 nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]));
2075 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
2076 config->dead_conn_timeout =
2077 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
2078 config->dead_conn_timeout *= HZ;
2080 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
2081 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
2082 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
2083 if (!test_and_set_bit(NBD_RT_DESTROY_ON_DISCONNECT,
2084 &config->runtime_flags))
2086 set_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags);
2088 if (test_and_clear_bit(NBD_RT_DESTROY_ON_DISCONNECT,
2089 &config->runtime_flags))
2090 refcount_inc(&nbd->refs);
2091 clear_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags);
2094 if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {
2095 set_bit(NBD_RT_DISCONNECT_ON_CLOSE,
2096 &config->runtime_flags);
2098 clear_bit(NBD_RT_DISCONNECT_ON_CLOSE,
2099 &config->runtime_flags);
2103 if (info->attrs[NBD_ATTR_SOCKETS]) {
2104 struct nlattr *attr;
2107 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
2109 struct nlattr *socks[NBD_SOCK_MAX+1];
2111 if (nla_type(attr) != NBD_SOCK_ITEM) {
2112 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");
2116 ret = nla_parse_nested_deprecated(socks, NBD_SOCK_MAX,
2121 printk(KERN_ERR "nbd: error processing sock list\n");
2125 if (!socks[NBD_SOCK_FD])
2127 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
2128 ret = nbd_reconnect_socket(nbd, fd);
2134 dev_info(nbd_to_dev(nbd), "reconnected socket\n");
2138 mutex_unlock(&nbd->config_lock);
2139 nbd_config_put(nbd);
2146 static const struct genl_small_ops nbd_connect_genl_ops[] = {
2148 .cmd = NBD_CMD_CONNECT,
2149 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2150 .doit = nbd_genl_connect,
2153 .cmd = NBD_CMD_DISCONNECT,
2154 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2155 .doit = nbd_genl_disconnect,
2158 .cmd = NBD_CMD_RECONFIGURE,
2159 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2160 .doit = nbd_genl_reconfigure,
2163 .cmd = NBD_CMD_STATUS,
2164 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2165 .doit = nbd_genl_status,
2169 static const struct genl_multicast_group nbd_mcast_grps[] = {
2170 { .name = NBD_GENL_MCAST_GROUP_NAME, },
2173 static struct genl_family nbd_genl_family __ro_after_init = {
2175 .name = NBD_GENL_FAMILY_NAME,
2176 .version = NBD_GENL_VERSION,
2177 .module = THIS_MODULE,
2178 .small_ops = nbd_connect_genl_ops,
2179 .n_small_ops = ARRAY_SIZE(nbd_connect_genl_ops),
2180 .maxattr = NBD_ATTR_MAX,
2181 .policy = nbd_attr_policy,
2182 .mcgrps = nbd_mcast_grps,
2183 .n_mcgrps = ARRAY_SIZE(nbd_mcast_grps),
2186 static int populate_nbd_status(struct nbd_device *nbd, struct sk_buff *reply)
2188 struct nlattr *dev_opt;
2192 /* This is a little racey, but for status it's ok. The
2193 * reason we don't take a ref here is because we can't
2194 * take a ref in the index == -1 case as we would need
2195 * to put under the nbd_index_mutex, which could
2196 * deadlock if we are configured to remove ourselves
2197 * once we're disconnected.
2199 if (refcount_read(&nbd->config_refs))
2201 dev_opt = nla_nest_start_noflag(reply, NBD_DEVICE_ITEM);
2204 ret = nla_put_u32(reply, NBD_DEVICE_INDEX, nbd->index);
2207 ret = nla_put_u8(reply, NBD_DEVICE_CONNECTED,
2211 nla_nest_end(reply, dev_opt);
2215 static int status_cb(int id, void *ptr, void *data)
2217 struct nbd_device *nbd = ptr;
2218 return populate_nbd_status(nbd, (struct sk_buff *)data);
2221 static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info)
2223 struct nlattr *dev_list;
2224 struct sk_buff *reply;
2230 if (info->attrs[NBD_ATTR_INDEX])
2231 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2233 mutex_lock(&nbd_index_mutex);
2235 msg_size = nla_total_size(nla_attr_size(sizeof(u32)) +
2236 nla_attr_size(sizeof(u8)));
2237 msg_size *= (index == -1) ? nbd_total_devices : 1;
2239 reply = genlmsg_new(msg_size, GFP_KERNEL);
2242 reply_head = genlmsg_put_reply(reply, info, &nbd_genl_family, 0,
2249 dev_list = nla_nest_start_noflag(reply, NBD_ATTR_DEVICE_LIST);
2251 ret = idr_for_each(&nbd_index_idr, &status_cb, reply);
2257 struct nbd_device *nbd;
2258 nbd = idr_find(&nbd_index_idr, index);
2260 ret = populate_nbd_status(nbd, reply);
2267 nla_nest_end(reply, dev_list);
2268 genlmsg_end(reply, reply_head);
2269 ret = genlmsg_reply(reply, info);
2271 mutex_unlock(&nbd_index_mutex);
2275 static void nbd_connect_reply(struct genl_info *info, int index)
2277 struct sk_buff *skb;
2281 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2284 msg_head = genlmsg_put_reply(skb, info, &nbd_genl_family, 0,
2290 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2295 genlmsg_end(skb, msg_head);
2296 genlmsg_reply(skb, info);
2299 static void nbd_mcast_index(int index)
2301 struct sk_buff *skb;
2305 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2308 msg_head = genlmsg_put(skb, 0, 0, &nbd_genl_family, 0,
2314 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2319 genlmsg_end(skb, msg_head);
2320 genlmsg_multicast(&nbd_genl_family, skb, 0, 0, GFP_KERNEL);
2323 static void nbd_dead_link_work(struct work_struct *work)
2325 struct link_dead_args *args = container_of(work, struct link_dead_args,
2327 nbd_mcast_index(args->index);
2331 static int __init nbd_init(void)
2335 BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
2338 printk(KERN_ERR "nbd: max_part must be >= 0\n");
2344 part_shift = fls(max_part);
2347 * Adjust max_part according to part_shift as it is exported
2348 * to user space so that user can know the max number of
2349 * partition kernel should be able to manage.
2351 * Note that -1 is required because partition 0 is reserved
2352 * for the whole disk.
2354 max_part = (1UL << part_shift) - 1;
2357 if ((1UL << part_shift) > DISK_MAX_PARTS)
2360 if (nbds_max > 1UL << (MINORBITS - part_shift))
2363 if (register_blkdev(NBD_MAJOR, "nbd"))
2366 if (genl_register_family(&nbd_genl_family)) {
2367 unregister_blkdev(NBD_MAJOR, "nbd");
2372 mutex_lock(&nbd_index_mutex);
2373 for (i = 0; i < nbds_max; i++)
2375 mutex_unlock(&nbd_index_mutex);
2379 static int nbd_exit_cb(int id, void *ptr, void *data)
2381 struct list_head *list = (struct list_head *)data;
2382 struct nbd_device *nbd = ptr;
2384 list_add_tail(&nbd->list, list);
2388 static void __exit nbd_cleanup(void)
2390 struct nbd_device *nbd;
2391 LIST_HEAD(del_list);
2395 mutex_lock(&nbd_index_mutex);
2396 idr_for_each(&nbd_index_idr, &nbd_exit_cb, &del_list);
2397 mutex_unlock(&nbd_index_mutex);
2399 while (!list_empty(&del_list)) {
2400 nbd = list_first_entry(&del_list, struct nbd_device, list);
2401 list_del_init(&nbd->list);
2402 if (refcount_read(&nbd->refs) != 1)
2403 printk(KERN_ERR "nbd: possibly leaking a device\n");
2407 idr_destroy(&nbd_index_idr);
2408 genl_unregister_family(&nbd_genl_family);
2409 unregister_blkdev(NBD_MAJOR, "nbd");
2412 module_init(nbd_init);
2413 module_exit(nbd_cleanup);
2415 MODULE_DESCRIPTION("Network Block Device");
2416 MODULE_LICENSE("GPL");
2418 module_param(nbds_max, int, 0444);
2419 MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
2420 module_param(max_part, int, 0444);
2421 MODULE_PARM_DESC(max_part, "number of partitions per device (default: 16)");