2 * Network block device - make block devices work over TCP
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.
7 * Copyright 1997-2000, 2008 Pavel Machek <pavel@ucw.cz>
8 * Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com>
10 * This file is released under GPLv2 or later.
12 * (part of code stolen from loop.c)
15 #include <linux/major.h>
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>
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>
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 static DEFINE_IDR(nbd_index_idr);
48 static DEFINE_MUTEX(nbd_index_mutex);
49 static int nbd_total_devices = 0;
54 struct request *pending;
61 struct recv_thread_args {
62 struct work_struct work;
63 struct nbd_device *nbd;
67 struct link_dead_args {
68 struct work_struct work;
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
78 #define NBD_DESTROY_ON_DISCONNECT 6
82 unsigned long runtime_flags;
83 u64 dead_conn_timeout;
85 struct nbd_sock **socks;
87 atomic_t live_connections;
88 wait_queue_head_t conn_wait;
90 atomic_t recv_threads;
91 wait_queue_head_t recv_wq;
94 #if IS_ENABLED(CONFIG_DEBUG_FS)
95 struct dentry *dbg_dir;
100 struct blk_mq_tag_set tag_set;
103 refcount_t config_refs;
105 struct nbd_config *config;
106 struct mutex config_lock;
107 struct gendisk *disk;
109 struct list_head list;
110 struct task_struct *task_recv;
111 struct task_struct *task_setup;
115 struct nbd_device *nbd;
118 struct completion send_complete;
122 #if IS_ENABLED(CONFIG_DEBUG_FS)
123 static struct dentry *nbd_dbg_dir;
126 #define nbd_name(nbd) ((nbd)->disk->disk_name)
128 #define NBD_MAGIC 0x68797548
130 static unsigned int nbds_max = 16;
132 static struct workqueue_struct *recv_workqueue;
133 static int part_shift;
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);
142 static inline struct device *nbd_to_dev(struct nbd_device *nbd)
144 return disk_to_dev(nbd->disk);
147 static const char *nbdcmd_to_ascii(int 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";
159 static ssize_t pid_show(struct device *dev,
160 struct device_attribute *attr, char *buf)
162 struct gendisk *disk = dev_to_disk(dev);
163 struct nbd_device *nbd = (struct nbd_device *)disk->private_data;
165 return sprintf(buf, "%d\n", task_pid_nr(nbd->task_recv));
168 static struct device_attribute pid_attr = {
169 .attr = { .name = "pid", .mode = S_IRUGO},
173 static void nbd_dev_remove(struct nbd_device *nbd)
175 struct gendisk *disk = nbd->disk;
178 blk_cleanup_queue(disk->queue);
179 blk_mq_free_tag_set(&nbd->tag_set);
180 disk->private_data = NULL;
186 static void nbd_put(struct nbd_device *nbd)
188 if (refcount_dec_and_mutex_lock(&nbd->refs,
190 idr_remove(&nbd_index_idr, nbd->index);
191 mutex_unlock(&nbd_index_mutex);
196 static int nbd_disconnected(struct nbd_config *config)
198 return test_bit(NBD_DISCONNECTED, &config->runtime_flags) ||
199 test_bit(NBD_DISCONNECT_REQUESTED, &config->runtime_flags);
202 static void nbd_mark_nsock_dead(struct nbd_device *nbd, struct nbd_sock *nsock,
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);
209 INIT_WORK(&args->work, nbd_dead_link_work);
210 args->index = nbd->index;
211 queue_work(system_wq, &args->work);
215 kernel_sock_shutdown(nsock->sock, SHUT_RDWR);
216 atomic_dec(&nbd->config->live_connections);
219 nsock->pending = NULL;
223 static void nbd_size_clear(struct nbd_device *nbd)
225 if (nbd->config->bytesize) {
226 set_capacity(nbd->disk, 0);
227 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
231 static void nbd_size_update(struct nbd_device *nbd)
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);
240 static void nbd_size_set(struct nbd_device *nbd, loff_t blocksize,
243 struct nbd_config *config = nbd->config;
244 config->blksize = blocksize;
245 config->bytesize = blocksize * nr_blocks;
246 nbd_size_update(nbd);
249 static void nbd_complete_rq(struct request *req)
251 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
253 dev_dbg(nbd_to_dev(cmd->nbd), "request %p: %s\n", cmd,
254 cmd->status ? "failed" : "done");
256 blk_mq_end_request(req, cmd->status);
260 * Forcibly shutdown the socket causing all listeners to error
262 static void sock_shutdown(struct nbd_device *nbd)
264 struct nbd_config *config = nbd->config;
267 if (config->num_connections == 0)
269 if (test_and_set_bit(NBD_DISCONNECTED, &config->runtime_flags))
272 for (i = 0; i < config->num_connections; i++) {
273 struct nbd_sock *nsock = config->socks[i];
274 mutex_lock(&nsock->tx_lock);
275 nbd_mark_nsock_dead(nbd, nsock, 0);
276 mutex_unlock(&nsock->tx_lock);
278 dev_warn(disk_to_dev(nbd->disk), "shutting down sockets\n");
281 static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
284 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
285 struct nbd_device *nbd = cmd->nbd;
286 struct nbd_config *config;
288 if (!refcount_inc_not_zero(&nbd->config_refs)) {
290 return BLK_EH_HANDLED;
293 /* If we are waiting on our dead timer then we could get timeout
294 * callbacks for our request. For this we just want to reset the timer
295 * and let the queue side take care of everything.
297 if (!completion_done(&cmd->send_complete)) {
299 return BLK_EH_RESET_TIMER;
301 config = nbd->config;
303 if (config->num_connections > 1) {
304 dev_err_ratelimited(nbd_to_dev(nbd),
305 "Connection timed out, retrying\n");
307 * Hooray we have more connections, requeue this IO, the submit
308 * path will put it on a real connection.
310 if (config->socks && config->num_connections > 1) {
311 if (cmd->index < config->num_connections) {
312 struct nbd_sock *nsock =
313 config->socks[cmd->index];
314 mutex_lock(&nsock->tx_lock);
315 /* We can have multiple outstanding requests, so
316 * we don't want to mark the nsock dead if we've
317 * already reconnected with a new socket, so
318 * only mark it dead if its the same socket we
321 if (cmd->cookie == nsock->cookie)
322 nbd_mark_nsock_dead(nbd, nsock, 1);
323 mutex_unlock(&nsock->tx_lock);
325 blk_mq_requeue_request(req, true);
327 return BLK_EH_NOT_HANDLED;
330 dev_err_ratelimited(nbd_to_dev(nbd),
331 "Connection timed out\n");
333 set_bit(NBD_TIMEDOUT, &config->runtime_flags);
338 return BLK_EH_HANDLED;
342 * Send or receive packet.
344 static int sock_xmit(struct nbd_device *nbd, int index, int send,
345 struct iov_iter *iter, int msg_flags, int *sent)
347 struct nbd_config *config = nbd->config;
348 struct socket *sock = config->socks[index]->sock;
351 unsigned int noreclaim_flag;
353 if (unlikely(!sock)) {
354 dev_err_ratelimited(disk_to_dev(nbd->disk),
355 "Attempted %s on closed socket in sock_xmit\n",
356 (send ? "send" : "recv"));
360 msg.msg_iter = *iter;
362 noreclaim_flag = memalloc_noreclaim_save();
364 sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC;
367 msg.msg_control = NULL;
368 msg.msg_controllen = 0;
369 msg.msg_flags = msg_flags | MSG_NOSIGNAL;
372 result = sock_sendmsg(sock, &msg);
374 result = sock_recvmsg(sock, &msg, msg.msg_flags);
378 result = -EPIPE; /* short read */
383 } while (msg_data_left(&msg));
385 memalloc_noreclaim_restore(noreclaim_flag);
390 /* always call with the tx_lock held */
391 static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
393 struct request *req = blk_mq_rq_from_pdu(cmd);
394 struct nbd_config *config = nbd->config;
395 struct nbd_sock *nsock = config->socks[index];
397 struct nbd_request request = {.magic = htonl(NBD_REQUEST_MAGIC)};
398 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
399 struct iov_iter from;
400 unsigned long size = blk_rq_bytes(req);
403 u32 tag = blk_mq_unique_tag(req);
404 int sent = nsock->sent, skip = 0;
406 iov_iter_kvec(&from, WRITE | ITER_KVEC, &iov, 1, sizeof(request));
408 switch (req_op(req)) {
413 type = NBD_CMD_FLUSH;
416 type = NBD_CMD_WRITE;
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");
432 /* We did a partial send previously, and we at least sent the whole
433 * request struct, so just go and send the rest of the pages in the
437 if (sent >= sizeof(request)) {
438 skip = sent - sizeof(request);
441 iov_iter_advance(&from, sent);
444 cmd->cookie = nsock->cookie;
445 request.type = htonl(type);
446 if (type != NBD_CMD_FLUSH) {
447 request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
448 request.len = htonl(size);
450 memcpy(request.handle, &tag, sizeof(tag));
452 dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n",
453 cmd, nbdcmd_to_ascii(type),
454 (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req));
455 result = sock_xmit(nbd, index, 1, &from,
456 (type == NBD_CMD_WRITE) ? MSG_MORE : 0, &sent);
458 if (result == -ERESTARTSYS) {
459 /* If we havne't sent anything we can just return BUSY,
460 * however if we have sent something we need to make
461 * sure we only allow this req to be sent until we are
465 nsock->pending = req;
468 return BLK_MQ_RQ_QUEUE_BUSY;
470 dev_err_ratelimited(disk_to_dev(nbd->disk),
471 "Send control failed (result %d)\n", result);
475 if (type != NBD_CMD_WRITE)
480 struct bio *next = bio->bi_next;
481 struct bvec_iter iter;
484 bio_for_each_segment(bvec, bio, iter) {
485 bool is_last = !next && bio_iter_last(bvec, iter);
486 int flags = is_last ? 0 : MSG_MORE;
488 dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n",
490 iov_iter_bvec(&from, ITER_BVEC | WRITE,
491 &bvec, 1, bvec.bv_len);
493 if (skip >= iov_iter_count(&from)) {
494 skip -= iov_iter_count(&from);
497 iov_iter_advance(&from, skip);
500 result = sock_xmit(nbd, index, 1, &from, flags, &sent);
502 if (result == -ERESTARTSYS) {
503 /* We've already sent the header, we
504 * have no choice but to set pending and
507 nsock->pending = req;
509 return BLK_MQ_RQ_QUEUE_BUSY;
511 dev_err(disk_to_dev(nbd->disk),
512 "Send data failed (result %d)\n",
517 * The completion might already have come in,
518 * so break for the last one instead of letting
519 * the iterator do it. This prevents use-after-free
528 nsock->pending = NULL;
533 /* NULL returned = something went wrong, inform userspace */
534 static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
536 struct nbd_config *config = nbd->config;
538 struct nbd_reply reply;
540 struct request *req = NULL;
543 struct kvec iov = {.iov_base = &reply, .iov_len = sizeof(reply)};
547 iov_iter_kvec(&to, READ | ITER_KVEC, &iov, 1, sizeof(reply));
548 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
550 if (!nbd_disconnected(config))
551 dev_err(disk_to_dev(nbd->disk),
552 "Receive control failed (result %d)\n", result);
553 return ERR_PTR(result);
556 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) {
557 dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n",
558 (unsigned long)ntohl(reply.magic));
559 return ERR_PTR(-EPROTO);
562 memcpy(&tag, reply.handle, sizeof(u32));
564 hwq = blk_mq_unique_tag_to_hwq(tag);
565 if (hwq < nbd->tag_set.nr_hw_queues)
566 req = blk_mq_tag_to_rq(nbd->tag_set.tags[hwq],
567 blk_mq_unique_tag_to_tag(tag));
568 if (!req || !blk_mq_request_started(req)) {
569 dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%d) %p\n",
571 return ERR_PTR(-ENOENT);
573 cmd = blk_mq_rq_to_pdu(req);
574 if (ntohl(reply.error)) {
575 dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n",
581 dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", cmd);
582 if (rq_data_dir(req) != WRITE) {
583 struct req_iterator iter;
586 rq_for_each_segment(bvec, req, iter) {
587 iov_iter_bvec(&to, ITER_BVEC | READ,
588 &bvec, 1, bvec.bv_len);
589 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
591 dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
594 * If we've disconnected or we only have 1
595 * connection then we need to make sure we
596 * complete this request, otherwise error out
597 * and let the timeout stuff handle resubmitting
598 * this request onto another connection.
600 if (nbd_disconnected(config) ||
601 config->num_connections <= 1) {
605 return ERR_PTR(-EIO);
607 dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n",
611 /* See the comment in nbd_queue_rq. */
612 wait_for_completion(&cmd->send_complete);
617 static void recv_work(struct work_struct *work)
619 struct recv_thread_args *args = container_of(work,
620 struct recv_thread_args,
622 struct nbd_device *nbd = args->nbd;
623 struct nbd_config *config = nbd->config;
628 cmd = nbd_read_stat(nbd, args->index);
630 struct nbd_sock *nsock = config->socks[args->index];
632 mutex_lock(&nsock->tx_lock);
633 nbd_mark_nsock_dead(nbd, nsock, 1);
634 mutex_unlock(&nsock->tx_lock);
639 blk_mq_complete_request(blk_mq_rq_from_pdu(cmd));
641 atomic_dec(&config->recv_threads);
642 wake_up(&config->recv_wq);
647 static void nbd_clear_req(struct request *req, void *data, bool reserved)
651 if (!blk_mq_request_started(req))
653 cmd = blk_mq_rq_to_pdu(req);
655 blk_mq_complete_request(req);
658 static void nbd_clear_que(struct nbd_device *nbd)
660 blk_mq_stop_hw_queues(nbd->disk->queue);
661 blk_mq_tagset_busy_iter(&nbd->tag_set, nbd_clear_req, NULL);
662 blk_mq_start_hw_queues(nbd->disk->queue);
663 dev_dbg(disk_to_dev(nbd->disk), "queue cleared\n");
666 static int find_fallback(struct nbd_device *nbd, int index)
668 struct nbd_config *config = nbd->config;
670 struct nbd_sock *nsock = config->socks[index];
671 int fallback = nsock->fallback_index;
673 if (test_bit(NBD_DISCONNECTED, &config->runtime_flags))
676 if (config->num_connections <= 1) {
677 dev_err_ratelimited(disk_to_dev(nbd->disk),
678 "Attempted send on invalid socket\n");
682 if (fallback >= 0 && fallback < config->num_connections &&
683 !config->socks[fallback]->dead)
686 if (nsock->fallback_index < 0 ||
687 nsock->fallback_index >= config->num_connections ||
688 config->socks[nsock->fallback_index]->dead) {
690 for (i = 0; i < config->num_connections; i++) {
693 if (!config->socks[i]->dead) {
698 nsock->fallback_index = new_index;
700 dev_err_ratelimited(disk_to_dev(nbd->disk),
701 "Dead connection, failed to find a fallback\n");
705 new_index = nsock->fallback_index;
709 static int wait_for_reconnect(struct nbd_device *nbd)
711 struct nbd_config *config = nbd->config;
712 if (!config->dead_conn_timeout)
714 if (test_bit(NBD_DISCONNECTED, &config->runtime_flags))
716 wait_event_interruptible_timeout(config->conn_wait,
717 atomic_read(&config->live_connections),
718 config->dead_conn_timeout);
719 return atomic_read(&config->live_connections);
722 static int nbd_handle_cmd(struct nbd_cmd *cmd, int index)
724 struct request *req = blk_mq_rq_from_pdu(cmd);
725 struct nbd_device *nbd = cmd->nbd;
726 struct nbd_config *config;
727 struct nbd_sock *nsock;
730 if (!refcount_inc_not_zero(&nbd->config_refs)) {
731 dev_err_ratelimited(disk_to_dev(nbd->disk),
732 "Socks array is empty\n");
735 config = nbd->config;
737 if (index >= config->num_connections) {
738 dev_err_ratelimited(disk_to_dev(nbd->disk),
739 "Attempted send on invalid socket\n");
745 nsock = config->socks[index];
746 mutex_lock(&nsock->tx_lock);
748 int old_index = index;
749 index = find_fallback(nbd, index);
750 mutex_unlock(&nsock->tx_lock);
752 if (wait_for_reconnect(nbd)) {
756 /* All the sockets should already be down at this point,
757 * we just want to make sure that DISCONNECTED is set so
758 * any requests that come in that were queue'ed waiting
759 * for the reconnect timer don't trigger the timer again
760 * and instead just error out.
769 /* Handle the case that we have a pending request that was partially
770 * transmitted that _has_ to be serviced first. We need to call requeue
771 * here so that it gets put _after_ the request that is already on the
774 if (unlikely(nsock->pending && nsock->pending != req)) {
775 blk_mq_requeue_request(req, true);
780 * Some failures are related to the link going down, so anything that
781 * returns EAGAIN can be retried on a different socket.
783 ret = nbd_send_cmd(nbd, cmd, index);
784 if (ret == -EAGAIN) {
785 dev_err_ratelimited(disk_to_dev(nbd->disk),
786 "Request send failed trying another connection\n");
787 nbd_mark_nsock_dead(nbd, nsock, 1);
788 mutex_unlock(&nsock->tx_lock);
792 mutex_unlock(&nsock->tx_lock);
797 static int nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
798 const struct blk_mq_queue_data *bd)
800 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
804 * Since we look at the bio's to send the request over the network we
805 * need to make sure the completion work doesn't mark this request done
806 * before we are done doing our send. This keeps us from dereferencing
807 * freed data if we have particularly fast completions (ie we get the
808 * completion before we exit sock_xmit on the last bvec) or in the case
809 * that the server is misbehaving (or there was an error) before we're
810 * done sending everything over the wire.
812 init_completion(&cmd->send_complete);
813 blk_mq_start_request(bd->rq);
815 /* We can be called directly from the user space process, which means we
816 * could possibly have signals pending so our sendmsg will fail. In
817 * this case we need to return that we are busy, otherwise error out as
820 ret = nbd_handle_cmd(cmd, hctx->queue_num);
822 ret = BLK_MQ_RQ_QUEUE_ERROR;
824 ret = BLK_MQ_RQ_QUEUE_OK;
825 complete(&cmd->send_complete);
830 static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
833 struct nbd_config *config = nbd->config;
835 struct nbd_sock **socks;
836 struct nbd_sock *nsock;
839 sock = sockfd_lookup(arg, &err);
843 if (!netlink && !nbd->task_setup &&
844 !test_bit(NBD_BOUND, &config->runtime_flags))
845 nbd->task_setup = current;
848 (nbd->task_setup != current ||
849 test_bit(NBD_BOUND, &config->runtime_flags))) {
850 dev_err(disk_to_dev(nbd->disk),
851 "Device being setup by another task");
856 socks = krealloc(config->socks, (config->num_connections + 1) *
857 sizeof(struct nbd_sock *), GFP_KERNEL);
862 nsock = kzalloc(sizeof(struct nbd_sock), GFP_KERNEL);
868 config->socks = socks;
870 nsock->fallback_index = -1;
872 mutex_init(&nsock->tx_lock);
874 nsock->pending = NULL;
877 socks[config->num_connections++] = nsock;
878 atomic_inc(&config->live_connections);
883 static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg)
885 struct nbd_config *config = nbd->config;
886 struct socket *sock, *old;
887 struct recv_thread_args *args;
891 sock = sockfd_lookup(arg, &err);
895 args = kzalloc(sizeof(*args), GFP_KERNEL);
901 for (i = 0; i < config->num_connections; i++) {
902 struct nbd_sock *nsock = config->socks[i];
907 mutex_lock(&nsock->tx_lock);
909 mutex_unlock(&nsock->tx_lock);
912 sk_set_memalloc(sock->sk);
913 atomic_inc(&config->recv_threads);
914 refcount_inc(&nbd->config_refs);
916 nsock->fallback_index = -1;
919 INIT_WORK(&args->work, recv_work);
923 mutex_unlock(&nsock->tx_lock);
926 /* We take the tx_mutex in an error path in the recv_work, so we
927 * need to queue_work outside of the tx_mutex.
929 queue_work(recv_workqueue, &args->work);
931 atomic_inc(&config->live_connections);
932 wake_up(&config->conn_wait);
940 /* Reset all properties of an NBD device */
941 static void nbd_reset(struct nbd_device *nbd)
944 nbd->tag_set.timeout = 0;
945 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
948 static void nbd_bdev_reset(struct block_device *bdev)
950 if (bdev->bd_openers > 1)
952 bd_set_size(bdev, 0);
954 blkdev_reread_part(bdev);
955 bdev->bd_invalidated = 1;
959 static void nbd_parse_flags(struct nbd_device *nbd)
961 struct nbd_config *config = nbd->config;
962 if (config->flags & NBD_FLAG_READ_ONLY)
963 set_disk_ro(nbd->disk, true);
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 blk_queue_write_cache(nbd->disk->queue, true, false);
971 blk_queue_write_cache(nbd->disk->queue, false, false);
974 static void send_disconnects(struct nbd_device *nbd)
976 struct nbd_config *config = nbd->config;
977 struct nbd_request request = {
978 .magic = htonl(NBD_REQUEST_MAGIC),
979 .type = htonl(NBD_CMD_DISC),
981 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
982 struct iov_iter from;
985 for (i = 0; i < config->num_connections; i++) {
986 iov_iter_kvec(&from, WRITE | ITER_KVEC, &iov, 1, sizeof(request));
987 ret = sock_xmit(nbd, i, 1, &from, 0, NULL);
989 dev_err(disk_to_dev(nbd->disk),
990 "Send disconnect failed %d\n", ret);
994 static int nbd_disconnect(struct nbd_device *nbd)
996 struct nbd_config *config = nbd->config;
998 dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
999 if (!test_and_set_bit(NBD_DISCONNECT_REQUESTED,
1000 &config->runtime_flags))
1001 send_disconnects(nbd);
1005 static void nbd_clear_sock(struct nbd_device *nbd)
1009 nbd->task_setup = NULL;
1012 static void nbd_config_put(struct nbd_device *nbd)
1014 if (refcount_dec_and_mutex_lock(&nbd->config_refs,
1015 &nbd->config_lock)) {
1016 struct nbd_config *config = nbd->config;
1017 nbd_dev_dbg_close(nbd);
1018 nbd_size_clear(nbd);
1019 if (test_and_clear_bit(NBD_HAS_PID_FILE,
1020 &config->runtime_flags))
1021 device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
1022 nbd->task_recv = NULL;
1023 nbd_clear_sock(nbd);
1024 if (config->num_connections) {
1026 for (i = 0; i < config->num_connections; i++) {
1027 sockfd_put(config->socks[i]->sock);
1028 kfree(config->socks[i]);
1030 kfree(config->socks);
1034 mutex_unlock(&nbd->config_lock);
1036 module_put(THIS_MODULE);
1040 static int nbd_start_device(struct nbd_device *nbd)
1042 struct nbd_config *config = nbd->config;
1043 int num_connections = config->num_connections;
1050 if (num_connections > 1 &&
1051 !(config->flags & NBD_FLAG_CAN_MULTI_CONN)) {
1052 dev_err(disk_to_dev(nbd->disk), "server does not support multiple connections per device.\n");
1056 blk_mq_update_nr_hw_queues(&nbd->tag_set, config->num_connections);
1057 nbd->task_recv = current;
1059 nbd_parse_flags(nbd);
1061 error = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
1063 dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n");
1066 set_bit(NBD_HAS_PID_FILE, &config->runtime_flags);
1068 nbd_dev_dbg_init(nbd);
1069 for (i = 0; i < num_connections; i++) {
1070 struct recv_thread_args *args;
1072 args = kzalloc(sizeof(*args), GFP_KERNEL);
1077 sk_set_memalloc(config->socks[i]->sock->sk);
1078 atomic_inc(&config->recv_threads);
1079 refcount_inc(&nbd->config_refs);
1080 INIT_WORK(&args->work, recv_work);
1083 queue_work(recv_workqueue, &args->work);
1088 static int nbd_start_device_ioctl(struct nbd_device *nbd, struct block_device *bdev)
1090 struct nbd_config *config = nbd->config;
1093 ret = nbd_start_device(nbd);
1097 bd_set_size(bdev, config->bytesize);
1099 bdev->bd_invalidated = 1;
1100 mutex_unlock(&nbd->config_lock);
1101 ret = wait_event_interruptible(config->recv_wq,
1102 atomic_read(&config->recv_threads) == 0);
1105 mutex_lock(&nbd->config_lock);
1106 bd_set_size(bdev, 0);
1107 /* user requested, ignore socket errors */
1108 if (test_bit(NBD_DISCONNECT_REQUESTED, &config->runtime_flags))
1110 if (test_bit(NBD_TIMEDOUT, &config->runtime_flags))
1115 static void nbd_clear_sock_ioctl(struct nbd_device *nbd,
1116 struct block_device *bdev)
1120 nbd_bdev_reset(bdev);
1121 if (test_and_clear_bit(NBD_HAS_CONFIG_REF,
1122 &nbd->config->runtime_flags))
1123 nbd_config_put(nbd);
1126 /* Must be called with config_lock held */
1127 static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
1128 unsigned int cmd, unsigned long arg)
1130 struct nbd_config *config = nbd->config;
1133 case NBD_DISCONNECT:
1134 return nbd_disconnect(nbd);
1135 case NBD_CLEAR_SOCK:
1136 nbd_clear_sock_ioctl(nbd, bdev);
1139 return nbd_add_socket(nbd, arg, false);
1140 case NBD_SET_BLKSIZE:
1141 nbd_size_set(nbd, arg,
1142 div_s64(config->bytesize, arg));
1145 nbd_size_set(nbd, config->blksize,
1146 div_s64(arg, config->blksize));
1148 case NBD_SET_SIZE_BLOCKS:
1149 nbd_size_set(nbd, config->blksize, arg);
1151 case NBD_SET_TIMEOUT:
1153 nbd->tag_set.timeout = arg * HZ;
1154 blk_queue_rq_timeout(nbd->disk->queue, arg * HZ);
1159 config->flags = arg;
1162 return nbd_start_device_ioctl(nbd, bdev);
1165 * This is for compatibility only. The queue is always cleared
1166 * by NBD_DO_IT or NBD_CLEAR_SOCK.
1169 case NBD_PRINT_DEBUG:
1171 * For compatibility only, we no longer keep a list of
1172 * outstanding requests.
1179 static int nbd_ioctl(struct block_device *bdev, fmode_t mode,
1180 unsigned int cmd, unsigned long arg)
1182 struct nbd_device *nbd = bdev->bd_disk->private_data;
1183 struct nbd_config *config = nbd->config;
1184 int error = -EINVAL;
1186 if (!capable(CAP_SYS_ADMIN))
1189 mutex_lock(&nbd->config_lock);
1191 /* Don't allow ioctl operations on a nbd device that was created with
1192 * netlink, unless it's DISCONNECT or CLEAR_SOCK, which are fine.
1194 if (!test_bit(NBD_BOUND, &config->runtime_flags) ||
1195 (cmd == NBD_DISCONNECT || cmd == NBD_CLEAR_SOCK))
1196 error = __nbd_ioctl(bdev, nbd, cmd, arg);
1198 dev_err(nbd_to_dev(nbd), "Cannot use ioctl interface on a netlink controlled device.\n");
1199 mutex_unlock(&nbd->config_lock);
1203 static struct nbd_config *nbd_alloc_config(void)
1205 struct nbd_config *config;
1207 config = kzalloc(sizeof(struct nbd_config), GFP_NOFS);
1210 atomic_set(&config->recv_threads, 0);
1211 init_waitqueue_head(&config->recv_wq);
1212 init_waitqueue_head(&config->conn_wait);
1213 config->blksize = 1024;
1214 atomic_set(&config->live_connections, 0);
1215 try_module_get(THIS_MODULE);
1219 static int nbd_open(struct block_device *bdev, fmode_t mode)
1221 struct nbd_device *nbd;
1224 mutex_lock(&nbd_index_mutex);
1225 nbd = bdev->bd_disk->private_data;
1230 if (!refcount_inc_not_zero(&nbd->refs)) {
1234 if (!refcount_inc_not_zero(&nbd->config_refs)) {
1235 struct nbd_config *config;
1237 mutex_lock(&nbd->config_lock);
1238 if (refcount_inc_not_zero(&nbd->config_refs)) {
1239 mutex_unlock(&nbd->config_lock);
1242 config = nbd->config = nbd_alloc_config();
1245 mutex_unlock(&nbd->config_lock);
1248 refcount_set(&nbd->config_refs, 1);
1249 refcount_inc(&nbd->refs);
1250 mutex_unlock(&nbd->config_lock);
1253 mutex_unlock(&nbd_index_mutex);
1257 static void nbd_release(struct gendisk *disk, fmode_t mode)
1259 struct nbd_device *nbd = disk->private_data;
1260 nbd_config_put(nbd);
1264 static const struct block_device_operations nbd_fops =
1266 .owner = THIS_MODULE,
1268 .release = nbd_release,
1270 .compat_ioctl = nbd_ioctl,
1273 #if IS_ENABLED(CONFIG_DEBUG_FS)
1275 static int nbd_dbg_tasks_show(struct seq_file *s, void *unused)
1277 struct nbd_device *nbd = s->private;
1280 seq_printf(s, "recv: %d\n", task_pid_nr(nbd->task_recv));
1285 static int nbd_dbg_tasks_open(struct inode *inode, struct file *file)
1287 return single_open(file, nbd_dbg_tasks_show, inode->i_private);
1290 static const struct file_operations nbd_dbg_tasks_ops = {
1291 .open = nbd_dbg_tasks_open,
1293 .llseek = seq_lseek,
1294 .release = single_release,
1297 static int nbd_dbg_flags_show(struct seq_file *s, void *unused)
1299 struct nbd_device *nbd = s->private;
1300 u32 flags = nbd->config->flags;
1302 seq_printf(s, "Hex: 0x%08x\n\n", flags);
1304 seq_puts(s, "Known flags:\n");
1306 if (flags & NBD_FLAG_HAS_FLAGS)
1307 seq_puts(s, "NBD_FLAG_HAS_FLAGS\n");
1308 if (flags & NBD_FLAG_READ_ONLY)
1309 seq_puts(s, "NBD_FLAG_READ_ONLY\n");
1310 if (flags & NBD_FLAG_SEND_FLUSH)
1311 seq_puts(s, "NBD_FLAG_SEND_FLUSH\n");
1312 if (flags & NBD_FLAG_SEND_TRIM)
1313 seq_puts(s, "NBD_FLAG_SEND_TRIM\n");
1318 static int nbd_dbg_flags_open(struct inode *inode, struct file *file)
1320 return single_open(file, nbd_dbg_flags_show, inode->i_private);
1323 static const struct file_operations nbd_dbg_flags_ops = {
1324 .open = nbd_dbg_flags_open,
1326 .llseek = seq_lseek,
1327 .release = single_release,
1330 static int nbd_dev_dbg_init(struct nbd_device *nbd)
1333 struct nbd_config *config = nbd->config;
1338 dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir);
1340 dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s'\n",
1344 config->dbg_dir = dir;
1346 debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_ops);
1347 debugfs_create_u64("size_bytes", 0444, dir, &config->bytesize);
1348 debugfs_create_u32("timeout", 0444, dir, &nbd->tag_set.timeout);
1349 debugfs_create_u64("blocksize", 0444, dir, &config->blksize);
1350 debugfs_create_file("flags", 0444, dir, nbd, &nbd_dbg_flags_ops);
1355 static void nbd_dev_dbg_close(struct nbd_device *nbd)
1357 debugfs_remove_recursive(nbd->config->dbg_dir);
1360 static int nbd_dbg_init(void)
1362 struct dentry *dbg_dir;
1364 dbg_dir = debugfs_create_dir("nbd", NULL);
1368 nbd_dbg_dir = dbg_dir;
1373 static void nbd_dbg_close(void)
1375 debugfs_remove_recursive(nbd_dbg_dir);
1378 #else /* IS_ENABLED(CONFIG_DEBUG_FS) */
1380 static int nbd_dev_dbg_init(struct nbd_device *nbd)
1385 static void nbd_dev_dbg_close(struct nbd_device *nbd)
1389 static int nbd_dbg_init(void)
1394 static void nbd_dbg_close(void)
1400 static int nbd_init_request(struct blk_mq_tag_set *set, struct request *rq,
1401 unsigned int hctx_idx, unsigned int numa_node)
1403 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq);
1404 cmd->nbd = set->driver_data;
1408 static const struct blk_mq_ops nbd_mq_ops = {
1409 .queue_rq = nbd_queue_rq,
1410 .complete = nbd_complete_rq,
1411 .init_request = nbd_init_request,
1412 .timeout = nbd_xmit_timeout,
1415 static int nbd_dev_add(int index)
1417 struct nbd_device *nbd;
1418 struct gendisk *disk;
1419 struct request_queue *q;
1422 nbd = kzalloc(sizeof(struct nbd_device), GFP_KERNEL);
1426 disk = alloc_disk(1 << part_shift);
1431 err = idr_alloc(&nbd_index_idr, nbd, index, index + 1,
1436 err = idr_alloc(&nbd_index_idr, nbd, 0, 0, GFP_KERNEL);
1445 nbd->tag_set.ops = &nbd_mq_ops;
1446 nbd->tag_set.nr_hw_queues = 1;
1447 nbd->tag_set.queue_depth = 128;
1448 nbd->tag_set.numa_node = NUMA_NO_NODE;
1449 nbd->tag_set.cmd_size = sizeof(struct nbd_cmd);
1450 nbd->tag_set.flags = BLK_MQ_F_SHOULD_MERGE |
1451 BLK_MQ_F_SG_MERGE | BLK_MQ_F_BLOCKING;
1452 nbd->tag_set.driver_data = nbd;
1454 err = blk_mq_alloc_tag_set(&nbd->tag_set);
1458 q = blk_mq_init_queue(&nbd->tag_set);
1466 * Tell the block layer that we are not a rotational device
1468 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue);
1469 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, disk->queue);
1470 disk->queue->limits.discard_granularity = 512;
1471 blk_queue_max_discard_sectors(disk->queue, UINT_MAX);
1472 blk_queue_max_segment_size(disk->queue, UINT_MAX);
1473 blk_queue_max_segments(disk->queue, USHRT_MAX);
1474 blk_queue_max_hw_sectors(disk->queue, 65536);
1475 disk->queue->limits.max_sectors = 256;
1477 mutex_init(&nbd->config_lock);
1478 refcount_set(&nbd->config_refs, 0);
1479 refcount_set(&nbd->refs, 1);
1480 INIT_LIST_HEAD(&nbd->list);
1481 disk->major = NBD_MAJOR;
1482 disk->first_minor = index << part_shift;
1483 disk->fops = &nbd_fops;
1484 disk->private_data = nbd;
1485 sprintf(disk->disk_name, "nbd%d", index);
1488 nbd_total_devices++;
1492 blk_mq_free_tag_set(&nbd->tag_set);
1494 idr_remove(&nbd_index_idr, index);
1503 static int find_free_cb(int id, void *ptr, void *data)
1505 struct nbd_device *nbd = ptr;
1506 struct nbd_device **found = data;
1508 if (!refcount_read(&nbd->config_refs)) {
1515 /* Netlink interface. */
1516 static struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = {
1517 [NBD_ATTR_INDEX] = { .type = NLA_U32 },
1518 [NBD_ATTR_SIZE_BYTES] = { .type = NLA_U64 },
1519 [NBD_ATTR_BLOCK_SIZE_BYTES] = { .type = NLA_U64 },
1520 [NBD_ATTR_TIMEOUT] = { .type = NLA_U64 },
1521 [NBD_ATTR_SERVER_FLAGS] = { .type = NLA_U64 },
1522 [NBD_ATTR_CLIENT_FLAGS] = { .type = NLA_U64 },
1523 [NBD_ATTR_SOCKETS] = { .type = NLA_NESTED},
1524 [NBD_ATTR_DEAD_CONN_TIMEOUT] = { .type = NLA_U64 },
1525 [NBD_ATTR_DEVICE_LIST] = { .type = NLA_NESTED},
1528 static struct nla_policy nbd_sock_policy[NBD_SOCK_MAX + 1] = {
1529 [NBD_SOCK_FD] = { .type = NLA_U32 },
1532 /* We don't use this right now since we don't parse the incoming list, but we
1533 * still want it here so userspace knows what to expect.
1535 static struct nla_policy __attribute__((unused))
1536 nbd_device_policy[NBD_DEVICE_ATTR_MAX + 1] = {
1537 [NBD_DEVICE_INDEX] = { .type = NLA_U32 },
1538 [NBD_DEVICE_CONNECTED] = { .type = NLA_U8 },
1541 static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
1543 struct nbd_device *nbd = NULL;
1544 struct nbd_config *config;
1547 bool put_dev = false;
1549 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1552 if (info->attrs[NBD_ATTR_INDEX])
1553 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1554 if (!info->attrs[NBD_ATTR_SOCKETS]) {
1555 printk(KERN_ERR "nbd: must specify at least one socket\n");
1558 if (!info->attrs[NBD_ATTR_SIZE_BYTES]) {
1559 printk(KERN_ERR "nbd: must specify a size in bytes for the device\n");
1563 mutex_lock(&nbd_index_mutex);
1565 ret = idr_for_each(&nbd_index_idr, &find_free_cb, &nbd);
1568 new_index = nbd_dev_add(-1);
1569 if (new_index < 0) {
1570 mutex_unlock(&nbd_index_mutex);
1571 printk(KERN_ERR "nbd: failed to add new device\n");
1574 nbd = idr_find(&nbd_index_idr, new_index);
1577 nbd = idr_find(&nbd_index_idr, index);
1580 printk(KERN_ERR "nbd: couldn't find device at index %d\n",
1582 mutex_unlock(&nbd_index_mutex);
1585 if (!refcount_inc_not_zero(&nbd->refs)) {
1586 mutex_unlock(&nbd_index_mutex);
1589 printk(KERN_ERR "nbd: device at index %d is going down\n",
1593 mutex_unlock(&nbd_index_mutex);
1595 mutex_lock(&nbd->config_lock);
1596 if (refcount_read(&nbd->config_refs)) {
1597 mutex_unlock(&nbd->config_lock);
1601 printk(KERN_ERR "nbd: nbd%d already in use\n", index);
1604 if (WARN_ON(nbd->config)) {
1605 mutex_unlock(&nbd->config_lock);
1609 config = nbd->config = nbd_alloc_config();
1611 mutex_unlock(&nbd->config_lock);
1613 printk(KERN_ERR "nbd: couldn't allocate config\n");
1616 refcount_set(&nbd->config_refs, 1);
1617 set_bit(NBD_BOUND, &config->runtime_flags);
1619 if (info->attrs[NBD_ATTR_SIZE_BYTES]) {
1620 u64 bytes = nla_get_u64(info->attrs[NBD_ATTR_SIZE_BYTES]);
1621 nbd_size_set(nbd, config->blksize,
1622 div64_u64(bytes, config->blksize));
1624 if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]) {
1626 nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]);
1627 nbd_size_set(nbd, bsize, div64_u64(config->bytesize, bsize));
1629 if (info->attrs[NBD_ATTR_TIMEOUT]) {
1630 u64 timeout = nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]);
1631 nbd->tag_set.timeout = timeout * HZ;
1632 blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ);
1634 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
1635 config->dead_conn_timeout =
1636 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
1637 config->dead_conn_timeout *= HZ;
1639 if (info->attrs[NBD_ATTR_SERVER_FLAGS])
1641 nla_get_u64(info->attrs[NBD_ATTR_SERVER_FLAGS]);
1642 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
1643 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
1644 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
1645 set_bit(NBD_DESTROY_ON_DISCONNECT,
1646 &config->runtime_flags);
1651 if (info->attrs[NBD_ATTR_SOCKETS]) {
1652 struct nlattr *attr;
1655 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
1657 struct nlattr *socks[NBD_SOCK_MAX+1];
1659 if (nla_type(attr) != NBD_SOCK_ITEM) {
1660 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");
1664 ret = nla_parse_nested(socks, NBD_SOCK_MAX, attr,
1665 nbd_sock_policy, info->extack);
1667 printk(KERN_ERR "nbd: error processing sock list\n");
1671 if (!socks[NBD_SOCK_FD])
1673 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
1674 ret = nbd_add_socket(nbd, fd, true);
1679 ret = nbd_start_device(nbd);
1681 mutex_unlock(&nbd->config_lock);
1683 set_bit(NBD_HAS_CONFIG_REF, &config->runtime_flags);
1684 refcount_inc(&nbd->config_refs);
1685 nbd_connect_reply(info, nbd->index);
1687 nbd_config_put(nbd);
1693 static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info)
1695 struct nbd_device *nbd;
1698 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1701 if (!info->attrs[NBD_ATTR_INDEX]) {
1702 printk(KERN_ERR "nbd: must specify an index to disconnect\n");
1705 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1706 mutex_lock(&nbd_index_mutex);
1707 nbd = idr_find(&nbd_index_idr, index);
1709 mutex_unlock(&nbd_index_mutex);
1710 printk(KERN_ERR "nbd: couldn't find device at index %d\n",
1714 if (!refcount_inc_not_zero(&nbd->refs)) {
1715 mutex_unlock(&nbd_index_mutex);
1716 printk(KERN_ERR "nbd: device at index %d is going down\n",
1720 mutex_unlock(&nbd_index_mutex);
1721 if (!refcount_inc_not_zero(&nbd->config_refs)) {
1725 mutex_lock(&nbd->config_lock);
1726 nbd_disconnect(nbd);
1727 mutex_unlock(&nbd->config_lock);
1728 if (test_and_clear_bit(NBD_HAS_CONFIG_REF,
1729 &nbd->config->runtime_flags))
1730 nbd_config_put(nbd);
1731 nbd_config_put(nbd);
1736 static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info)
1738 struct nbd_device *nbd = NULL;
1739 struct nbd_config *config;
1742 bool put_dev = false;
1744 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1747 if (!info->attrs[NBD_ATTR_INDEX]) {
1748 printk(KERN_ERR "nbd: must specify a device to reconfigure\n");
1751 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1752 mutex_lock(&nbd_index_mutex);
1753 nbd = idr_find(&nbd_index_idr, index);
1755 mutex_unlock(&nbd_index_mutex);
1756 printk(KERN_ERR "nbd: couldn't find a device at index %d\n",
1760 if (!refcount_inc_not_zero(&nbd->refs)) {
1761 mutex_unlock(&nbd_index_mutex);
1762 printk(KERN_ERR "nbd: device at index %d is going down\n",
1766 mutex_unlock(&nbd_index_mutex);
1768 if (!refcount_inc_not_zero(&nbd->config_refs)) {
1769 dev_err(nbd_to_dev(nbd),
1770 "not configured, cannot reconfigure\n");
1775 mutex_lock(&nbd->config_lock);
1776 config = nbd->config;
1777 if (!test_bit(NBD_BOUND, &config->runtime_flags) ||
1779 dev_err(nbd_to_dev(nbd),
1780 "not configured, cannot reconfigure\n");
1784 if (info->attrs[NBD_ATTR_TIMEOUT]) {
1785 u64 timeout = nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]);
1786 nbd->tag_set.timeout = timeout * HZ;
1787 blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ);
1789 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
1790 config->dead_conn_timeout =
1791 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
1792 config->dead_conn_timeout *= HZ;
1794 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
1795 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
1796 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
1797 if (!test_and_set_bit(NBD_DESTROY_ON_DISCONNECT,
1798 &config->runtime_flags))
1801 if (test_and_clear_bit(NBD_DESTROY_ON_DISCONNECT,
1802 &config->runtime_flags))
1803 refcount_inc(&nbd->refs);
1807 if (info->attrs[NBD_ATTR_SOCKETS]) {
1808 struct nlattr *attr;
1811 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
1813 struct nlattr *socks[NBD_SOCK_MAX+1];
1815 if (nla_type(attr) != NBD_SOCK_ITEM) {
1816 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");
1820 ret = nla_parse_nested(socks, NBD_SOCK_MAX, attr,
1821 nbd_sock_policy, info->extack);
1823 printk(KERN_ERR "nbd: error processing sock list\n");
1827 if (!socks[NBD_SOCK_FD])
1829 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
1830 ret = nbd_reconnect_socket(nbd, fd);
1836 dev_info(nbd_to_dev(nbd), "reconnected socket\n");
1840 mutex_unlock(&nbd->config_lock);
1841 nbd_config_put(nbd);
1848 static const struct genl_ops nbd_connect_genl_ops[] = {
1850 .cmd = NBD_CMD_CONNECT,
1851 .policy = nbd_attr_policy,
1852 .doit = nbd_genl_connect,
1855 .cmd = NBD_CMD_DISCONNECT,
1856 .policy = nbd_attr_policy,
1857 .doit = nbd_genl_disconnect,
1860 .cmd = NBD_CMD_RECONFIGURE,
1861 .policy = nbd_attr_policy,
1862 .doit = nbd_genl_reconfigure,
1865 .cmd = NBD_CMD_STATUS,
1866 .policy = nbd_attr_policy,
1867 .doit = nbd_genl_status,
1871 static const struct genl_multicast_group nbd_mcast_grps[] = {
1872 { .name = NBD_GENL_MCAST_GROUP_NAME, },
1875 static struct genl_family nbd_genl_family __ro_after_init = {
1877 .name = NBD_GENL_FAMILY_NAME,
1878 .version = NBD_GENL_VERSION,
1879 .module = THIS_MODULE,
1880 .ops = nbd_connect_genl_ops,
1881 .n_ops = ARRAY_SIZE(nbd_connect_genl_ops),
1882 .maxattr = NBD_ATTR_MAX,
1883 .mcgrps = nbd_mcast_grps,
1884 .n_mcgrps = ARRAY_SIZE(nbd_mcast_grps),
1887 static int populate_nbd_status(struct nbd_device *nbd, struct sk_buff *reply)
1889 struct nlattr *dev_opt;
1893 /* This is a little racey, but for status it's ok. The
1894 * reason we don't take a ref here is because we can't
1895 * take a ref in the index == -1 case as we would need
1896 * to put under the nbd_index_mutex, which could
1897 * deadlock if we are configured to remove ourselves
1898 * once we're disconnected.
1900 if (refcount_read(&nbd->config_refs))
1902 dev_opt = nla_nest_start(reply, NBD_DEVICE_ITEM);
1905 ret = nla_put_u32(reply, NBD_DEVICE_INDEX, nbd->index);
1908 ret = nla_put_u8(reply, NBD_DEVICE_CONNECTED,
1912 nla_nest_end(reply, dev_opt);
1916 static int status_cb(int id, void *ptr, void *data)
1918 struct nbd_device *nbd = ptr;
1919 return populate_nbd_status(nbd, (struct sk_buff *)data);
1922 static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info)
1924 struct nlattr *dev_list;
1925 struct sk_buff *reply;
1931 if (info->attrs[NBD_ATTR_INDEX])
1932 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1934 mutex_lock(&nbd_index_mutex);
1936 msg_size = nla_total_size(nla_attr_size(sizeof(u32)) +
1937 nla_attr_size(sizeof(u8)));
1938 msg_size *= (index == -1) ? nbd_total_devices : 1;
1940 reply = genlmsg_new(msg_size, GFP_KERNEL);
1943 reply_head = genlmsg_put_reply(reply, info, &nbd_genl_family, 0,
1950 dev_list = nla_nest_start(reply, NBD_ATTR_DEVICE_LIST);
1952 ret = idr_for_each(&nbd_index_idr, &status_cb, reply);
1958 struct nbd_device *nbd;
1959 nbd = idr_find(&nbd_index_idr, index);
1961 ret = populate_nbd_status(nbd, reply);
1968 nla_nest_end(reply, dev_list);
1969 genlmsg_end(reply, reply_head);
1970 genlmsg_reply(reply, info);
1973 mutex_unlock(&nbd_index_mutex);
1977 static void nbd_connect_reply(struct genl_info *info, int index)
1979 struct sk_buff *skb;
1983 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
1986 msg_head = genlmsg_put_reply(skb, info, &nbd_genl_family, 0,
1992 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
1997 genlmsg_end(skb, msg_head);
1998 genlmsg_reply(skb, info);
2001 static void nbd_mcast_index(int index)
2003 struct sk_buff *skb;
2007 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2010 msg_head = genlmsg_put(skb, 0, 0, &nbd_genl_family, 0,
2016 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2021 genlmsg_end(skb, msg_head);
2022 genlmsg_multicast(&nbd_genl_family, skb, 0, 0, GFP_KERNEL);
2025 static void nbd_dead_link_work(struct work_struct *work)
2027 struct link_dead_args *args = container_of(work, struct link_dead_args,
2029 nbd_mcast_index(args->index);
2033 static int __init nbd_init(void)
2037 BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
2040 printk(KERN_ERR "nbd: max_part must be >= 0\n");
2046 part_shift = fls(max_part);
2049 * Adjust max_part according to part_shift as it is exported
2050 * to user space so that user can know the max number of
2051 * partition kernel should be able to manage.
2053 * Note that -1 is required because partition 0 is reserved
2054 * for the whole disk.
2056 max_part = (1UL << part_shift) - 1;
2059 if ((1UL << part_shift) > DISK_MAX_PARTS)
2062 if (nbds_max > 1UL << (MINORBITS - part_shift))
2064 recv_workqueue = alloc_workqueue("knbd-recv",
2065 WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
2066 if (!recv_workqueue)
2069 if (register_blkdev(NBD_MAJOR, "nbd")) {
2070 destroy_workqueue(recv_workqueue);
2074 if (genl_register_family(&nbd_genl_family)) {
2075 unregister_blkdev(NBD_MAJOR, "nbd");
2076 destroy_workqueue(recv_workqueue);
2081 mutex_lock(&nbd_index_mutex);
2082 for (i = 0; i < nbds_max; i++)
2084 mutex_unlock(&nbd_index_mutex);
2088 static int nbd_exit_cb(int id, void *ptr, void *data)
2090 struct list_head *list = (struct list_head *)data;
2091 struct nbd_device *nbd = ptr;
2093 list_add_tail(&nbd->list, list);
2097 static void __exit nbd_cleanup(void)
2099 struct nbd_device *nbd;
2100 LIST_HEAD(del_list);
2104 mutex_lock(&nbd_index_mutex);
2105 idr_for_each(&nbd_index_idr, &nbd_exit_cb, &del_list);
2106 mutex_unlock(&nbd_index_mutex);
2108 while (!list_empty(&del_list)) {
2109 nbd = list_first_entry(&del_list, struct nbd_device, list);
2110 list_del_init(&nbd->list);
2111 if (refcount_read(&nbd->refs) != 1)
2112 printk(KERN_ERR "nbd: possibly leaking a device\n");
2116 idr_destroy(&nbd_index_idr);
2117 genl_unregister_family(&nbd_genl_family);
2118 destroy_workqueue(recv_workqueue);
2119 unregister_blkdev(NBD_MAJOR, "nbd");
2122 module_init(nbd_init);
2123 module_exit(nbd_cleanup);
2125 MODULE_DESCRIPTION("Network Block Device");
2126 MODULE_LICENSE("GPL");
2128 module_param(nbds_max, int, 0444);
2129 MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
2130 module_param(max_part, int, 0444);
2131 MODULE_PARM_DESC(max_part, "number of partitions per device (default: 0)");