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>
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/err.h>
30 #include <linux/kernel.h>
31 #include <linux/slab.h>
33 #include <linux/net.h>
34 #include <linux/kthread.h>
35 #include <linux/types.h>
36 #include <linux/debugfs.h>
37 #include <linux/blk-mq.h>
39 #include <linux/uaccess.h>
40 #include <asm/types.h>
42 #include <linux/nbd.h>
44 static DEFINE_IDR(nbd_index_idr);
45 static DEFINE_MUTEX(nbd_index_mutex);
52 #define NBD_TIMEDOUT 0
53 #define NBD_DISCONNECT_REQUESTED 1
54 #define NBD_DISCONNECTED 2
59 unsigned long runtime_flags;
60 struct nbd_sock **socks;
63 struct blk_mq_tag_set tag_set;
65 struct mutex config_lock;
68 atomic_t recv_threads;
69 wait_queue_head_t recv_wq;
73 struct task_struct *task_recv;
74 struct task_struct *task_setup;
76 #if IS_ENABLED(CONFIG_DEBUG_FS)
77 struct dentry *dbg_dir;
82 struct nbd_device *nbd;
83 struct completion send_complete;
86 #if IS_ENABLED(CONFIG_DEBUG_FS)
87 static struct dentry *nbd_dbg_dir;
90 #define nbd_name(nbd) ((nbd)->disk->disk_name)
92 #define NBD_MAGIC 0x68797548
94 static unsigned int nbds_max = 16;
96 static struct workqueue_struct *recv_workqueue;
97 static int part_shift;
99 static int nbd_dev_dbg_init(struct nbd_device *nbd);
100 static void nbd_dev_dbg_close(struct nbd_device *nbd);
103 static inline struct device *nbd_to_dev(struct nbd_device *nbd)
105 return disk_to_dev(nbd->disk);
108 static bool nbd_is_connected(struct nbd_device *nbd)
110 return !!nbd->task_recv;
113 static const char *nbdcmd_to_ascii(int cmd)
116 case NBD_CMD_READ: return "read";
117 case NBD_CMD_WRITE: return "write";
118 case NBD_CMD_DISC: return "disconnect";
119 case NBD_CMD_FLUSH: return "flush";
120 case NBD_CMD_TRIM: return "trim/discard";
125 static int nbd_size_clear(struct nbd_device *nbd, struct block_device *bdev)
127 bd_set_size(bdev, 0);
128 set_capacity(nbd->disk, 0);
129 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
134 static void nbd_size_update(struct nbd_device *nbd, struct block_device *bdev)
136 blk_queue_logical_block_size(nbd->disk->queue, nbd->blksize);
137 blk_queue_physical_block_size(nbd->disk->queue, nbd->blksize);
138 bd_set_size(bdev, nbd->bytesize);
139 set_capacity(nbd->disk, nbd->bytesize >> 9);
140 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
143 static void nbd_size_set(struct nbd_device *nbd, struct block_device *bdev,
144 loff_t blocksize, loff_t nr_blocks)
146 nbd->blksize = blocksize;
147 nbd->bytesize = blocksize * nr_blocks;
148 if (nbd_is_connected(nbd))
149 nbd_size_update(nbd, bdev);
152 static void nbd_end_request(struct nbd_cmd *cmd)
154 struct nbd_device *nbd = cmd->nbd;
155 struct request *req = blk_mq_rq_from_pdu(cmd);
156 int error = req->errors ? -EIO : 0;
158 dev_dbg(nbd_to_dev(nbd), "request %p: %s\n", cmd,
159 error ? "failed" : "done");
161 blk_mq_complete_request(req, error);
165 * Forcibly shutdown the socket causing all listeners to error
167 static void sock_shutdown(struct nbd_device *nbd)
171 if (nbd->num_connections == 0)
173 if (test_and_set_bit(NBD_DISCONNECTED, &nbd->runtime_flags))
176 for (i = 0; i < nbd->num_connections; i++) {
177 struct nbd_sock *nsock = nbd->socks[i];
178 mutex_lock(&nsock->tx_lock);
179 kernel_sock_shutdown(nsock->sock, SHUT_RDWR);
180 mutex_unlock(&nsock->tx_lock);
182 dev_warn(disk_to_dev(nbd->disk), "shutting down sockets\n");
185 static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
188 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
189 struct nbd_device *nbd = cmd->nbd;
191 dev_err(nbd_to_dev(nbd), "Connection timed out, shutting down connection\n");
192 set_bit(NBD_TIMEDOUT, &nbd->runtime_flags);
195 mutex_lock(&nbd->config_lock);
197 mutex_unlock(&nbd->config_lock);
198 return BLK_EH_HANDLED;
202 * Send or receive packet.
204 static int sock_xmit(struct nbd_device *nbd, int index, int send,
205 struct iov_iter *iter, int msg_flags)
207 struct socket *sock = nbd->socks[index]->sock;
210 unsigned long pflags = current->flags;
212 if (unlikely(!sock)) {
213 dev_err_ratelimited(disk_to_dev(nbd->disk),
214 "Attempted %s on closed socket in sock_xmit\n",
215 (send ? "send" : "recv"));
219 msg.msg_iter = *iter;
221 current->flags |= PF_MEMALLOC;
223 sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC;
226 msg.msg_control = NULL;
227 msg.msg_controllen = 0;
228 msg.msg_flags = msg_flags | MSG_NOSIGNAL;
231 result = sock_sendmsg(sock, &msg);
233 result = sock_recvmsg(sock, &msg, msg.msg_flags);
237 result = -EPIPE; /* short read */
240 } while (msg_data_left(&msg));
242 tsk_restore_flags(current, pflags, PF_MEMALLOC);
247 /* always call with the tx_lock held */
248 static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
250 struct request *req = blk_mq_rq_from_pdu(cmd);
252 struct nbd_request request = {.magic = htonl(NBD_REQUEST_MAGIC)};
253 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
254 struct iov_iter from;
255 unsigned long size = blk_rq_bytes(req);
258 u32 tag = blk_mq_unique_tag(req);
260 iov_iter_kvec(&from, WRITE | ITER_KVEC, &iov, 1, sizeof(request));
262 switch (req_op(req)) {
267 type = NBD_CMD_FLUSH;
270 type = NBD_CMD_WRITE;
279 if (rq_data_dir(req) == WRITE &&
280 (nbd->flags & NBD_FLAG_READ_ONLY)) {
281 dev_err_ratelimited(disk_to_dev(nbd->disk),
282 "Write on read-only\n");
286 request.type = htonl(type);
287 if (type != NBD_CMD_FLUSH) {
288 request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
289 request.len = htonl(size);
291 memcpy(request.handle, &tag, sizeof(tag));
293 dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n",
294 cmd, nbdcmd_to_ascii(type),
295 (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req));
296 result = sock_xmit(nbd, index, 1, &from,
297 (type == NBD_CMD_WRITE) ? MSG_MORE : 0);
299 dev_err_ratelimited(disk_to_dev(nbd->disk),
300 "Send control failed (result %d)\n", result);
304 if (type != NBD_CMD_WRITE)
309 struct bio *next = bio->bi_next;
310 struct bvec_iter iter;
313 bio_for_each_segment(bvec, bio, iter) {
314 bool is_last = !next && bio_iter_last(bvec, iter);
315 int flags = is_last ? 0 : MSG_MORE;
317 dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n",
319 iov_iter_bvec(&from, ITER_BVEC | WRITE,
320 &bvec, 1, bvec.bv_len);
321 result = sock_xmit(nbd, index, 1, &from, flags);
323 dev_err(disk_to_dev(nbd->disk),
324 "Send data failed (result %d)\n",
329 * The completion might already have come in,
330 * so break for the last one instead of letting
331 * the iterator do it. This prevents use-after-free
342 /* NULL returned = something went wrong, inform userspace */
343 static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
346 struct nbd_reply reply;
348 struct request *req = NULL;
351 struct kvec iov = {.iov_base = &reply, .iov_len = sizeof(reply)};
355 iov_iter_kvec(&to, READ | ITER_KVEC, &iov, 1, sizeof(reply));
356 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL);
358 if (!test_bit(NBD_DISCONNECTED, &nbd->runtime_flags) &&
359 !test_bit(NBD_DISCONNECT_REQUESTED, &nbd->runtime_flags))
360 dev_err(disk_to_dev(nbd->disk),
361 "Receive control failed (result %d)\n", result);
362 return ERR_PTR(result);
365 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) {
366 dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n",
367 (unsigned long)ntohl(reply.magic));
368 return ERR_PTR(-EPROTO);
371 memcpy(&tag, reply.handle, sizeof(u32));
373 hwq = blk_mq_unique_tag_to_hwq(tag);
374 if (hwq < nbd->tag_set.nr_hw_queues)
375 req = blk_mq_tag_to_rq(nbd->tag_set.tags[hwq],
376 blk_mq_unique_tag_to_tag(tag));
377 if (!req || !blk_mq_request_started(req)) {
378 dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%d) %p\n",
380 return ERR_PTR(-ENOENT);
382 cmd = blk_mq_rq_to_pdu(req);
383 if (ntohl(reply.error)) {
384 dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n",
390 dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", cmd);
391 if (rq_data_dir(req) != WRITE) {
392 struct req_iterator iter;
395 rq_for_each_segment(bvec, req, iter) {
396 iov_iter_bvec(&to, ITER_BVEC | READ,
397 &bvec, 1, bvec.bv_len);
398 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL);
400 dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
405 dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n",
409 /* See the comment in nbd_queue_rq. */
410 wait_for_completion(&cmd->send_complete);
415 static ssize_t pid_show(struct device *dev,
416 struct device_attribute *attr, char *buf)
418 struct gendisk *disk = dev_to_disk(dev);
419 struct nbd_device *nbd = (struct nbd_device *)disk->private_data;
421 return sprintf(buf, "%d\n", task_pid_nr(nbd->task_recv));
424 static struct device_attribute pid_attr = {
425 .attr = { .name = "pid", .mode = S_IRUGO},
429 struct recv_thread_args {
430 struct work_struct work;
431 struct nbd_device *nbd;
435 static void recv_work(struct work_struct *work)
437 struct recv_thread_args *args = container_of(work,
438 struct recv_thread_args,
440 struct nbd_device *nbd = args->nbd;
444 BUG_ON(nbd->magic != NBD_MAGIC);
446 cmd = nbd_read_stat(nbd, args->index);
452 nbd_end_request(cmd);
456 * We got an error, shut everybody down if this wasn't the result of a
457 * disconnect request.
459 if (ret && !test_bit(NBD_DISCONNECT_REQUESTED, &nbd->runtime_flags))
461 atomic_dec(&nbd->recv_threads);
462 wake_up(&nbd->recv_wq);
465 static void nbd_clear_req(struct request *req, void *data, bool reserved)
469 if (!blk_mq_request_started(req))
471 cmd = blk_mq_rq_to_pdu(req);
473 nbd_end_request(cmd);
476 static void nbd_clear_que(struct nbd_device *nbd)
478 BUG_ON(nbd->magic != NBD_MAGIC);
480 blk_mq_tagset_busy_iter(&nbd->tag_set, nbd_clear_req, NULL);
481 dev_dbg(disk_to_dev(nbd->disk), "queue cleared\n");
485 static void nbd_handle_cmd(struct nbd_cmd *cmd, int index)
487 struct request *req = blk_mq_rq_from_pdu(cmd);
488 struct nbd_device *nbd = cmd->nbd;
489 struct nbd_sock *nsock;
491 if (index >= nbd->num_connections) {
492 dev_err_ratelimited(disk_to_dev(nbd->disk),
493 "Attempted send on invalid socket\n");
497 if (test_bit(NBD_DISCONNECTED, &nbd->runtime_flags)) {
498 dev_err_ratelimited(disk_to_dev(nbd->disk),
499 "Attempted send on closed socket\n");
505 nsock = nbd->socks[index];
506 mutex_lock(&nsock->tx_lock);
507 if (unlikely(!nsock->sock)) {
508 mutex_unlock(&nsock->tx_lock);
509 dev_err_ratelimited(disk_to_dev(nbd->disk),
510 "Attempted send on closed socket\n");
514 if (nbd_send_cmd(nbd, cmd, index) != 0) {
515 dev_err_ratelimited(disk_to_dev(nbd->disk),
516 "Request send failed\n");
518 nbd_end_request(cmd);
521 mutex_unlock(&nsock->tx_lock);
527 nbd_end_request(cmd);
530 static int nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
531 const struct blk_mq_queue_data *bd)
533 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
536 * Since we look at the bio's to send the request over the network we
537 * need to make sure the completion work doesn't mark this request done
538 * before we are done doing our send. This keeps us from dereferencing
539 * freed data if we have particularly fast completions (ie we get the
540 * completion before we exit sock_xmit on the last bvec) or in the case
541 * that the server is misbehaving (or there was an error) before we're
542 * done sending everything over the wire.
544 init_completion(&cmd->send_complete);
545 blk_mq_start_request(bd->rq);
546 nbd_handle_cmd(cmd, hctx->queue_num);
547 complete(&cmd->send_complete);
549 return BLK_MQ_RQ_QUEUE_OK;
552 static int nbd_add_socket(struct nbd_device *nbd, struct block_device *bdev,
556 struct nbd_sock **socks;
557 struct nbd_sock *nsock;
560 sock = sockfd_lookup(arg, &err);
564 if (!nbd->task_setup)
565 nbd->task_setup = current;
566 if (nbd->task_setup != current) {
567 dev_err(disk_to_dev(nbd->disk),
568 "Device being setup by another task");
572 socks = krealloc(nbd->socks, (nbd->num_connections + 1) *
573 sizeof(struct nbd_sock *), GFP_KERNEL);
576 nsock = kzalloc(sizeof(struct nbd_sock), GFP_KERNEL);
582 mutex_init(&nsock->tx_lock);
584 socks[nbd->num_connections++] = nsock;
587 bdev->bd_invalidated = 1;
591 /* Reset all properties of an NBD device */
592 static void nbd_reset(struct nbd_device *nbd)
594 nbd->runtime_flags = 0;
597 set_capacity(nbd->disk, 0);
599 nbd->tag_set.timeout = 0;
600 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
603 static void nbd_bdev_reset(struct block_device *bdev)
605 set_device_ro(bdev, false);
606 bdev->bd_inode->i_size = 0;
608 blkdev_reread_part(bdev);
609 bdev->bd_invalidated = 1;
613 static void nbd_parse_flags(struct nbd_device *nbd, struct block_device *bdev)
615 if (nbd->flags & NBD_FLAG_READ_ONLY)
616 set_device_ro(bdev, true);
617 if (nbd->flags & NBD_FLAG_SEND_TRIM)
618 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
619 if (nbd->flags & NBD_FLAG_SEND_FLUSH)
620 blk_queue_write_cache(nbd->disk->queue, true, false);
622 blk_queue_write_cache(nbd->disk->queue, false, false);
625 static void send_disconnects(struct nbd_device *nbd)
627 struct nbd_request request = {
628 .magic = htonl(NBD_REQUEST_MAGIC),
629 .type = htonl(NBD_CMD_DISC),
631 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
632 struct iov_iter from;
635 for (i = 0; i < nbd->num_connections; i++) {
636 iov_iter_kvec(&from, WRITE | ITER_KVEC, &iov, 1, sizeof(request));
637 ret = sock_xmit(nbd, i, 1, &from, 0);
639 dev_err(disk_to_dev(nbd->disk),
640 "Send disconnect failed %d\n", ret);
644 static int nbd_disconnect(struct nbd_device *nbd, struct block_device *bdev)
646 dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
650 mutex_unlock(&nbd->config_lock);
652 mutex_lock(&nbd->config_lock);
654 /* Check again after getting mutex back. */
658 if (!test_and_set_bit(NBD_DISCONNECT_REQUESTED,
659 &nbd->runtime_flags))
660 send_disconnects(nbd);
664 static int nbd_clear_sock(struct nbd_device *nbd, struct block_device *bdev)
669 nbd_bdev_reset(bdev);
671 * We want to give the run thread a chance to wait for everybody
672 * to clean up and then do it's own cleanup.
674 if (!test_bit(NBD_RUNNING, &nbd->runtime_flags) &&
675 nbd->num_connections) {
678 for (i = 0; i < nbd->num_connections; i++) {
679 sockfd_put(nbd->socks[i]->sock);
680 kfree(nbd->socks[i]);
684 nbd->num_connections = 0;
686 nbd->task_setup = NULL;
691 static int nbd_start_device(struct nbd_device *nbd, struct block_device *bdev)
693 struct recv_thread_args *args;
694 int num_connections = nbd->num_connections;
701 if (num_connections > 1 &&
702 !(nbd->flags & NBD_FLAG_CAN_MULTI_CONN)) {
703 dev_err(disk_to_dev(nbd->disk), "server does not support multiple connections per device.\n");
708 set_bit(NBD_RUNNING, &nbd->runtime_flags);
709 blk_mq_update_nr_hw_queues(&nbd->tag_set, nbd->num_connections);
710 args = kcalloc(num_connections, sizeof(*args), GFP_KERNEL);
715 nbd->task_recv = current;
716 mutex_unlock(&nbd->config_lock);
718 nbd_parse_flags(nbd, bdev);
720 error = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
722 dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n");
726 nbd_size_update(nbd, bdev);
728 nbd_dev_dbg_init(nbd);
729 for (i = 0; i < num_connections; i++) {
730 sk_set_memalloc(nbd->socks[i]->sock->sk);
731 atomic_inc(&nbd->recv_threads);
732 INIT_WORK(&args[i].work, recv_work);
735 queue_work(recv_workqueue, &args[i].work);
737 wait_event_interruptible(nbd->recv_wq,
738 atomic_read(&nbd->recv_threads) == 0);
739 for (i = 0; i < num_connections; i++)
740 flush_work(&args[i].work);
741 nbd_dev_dbg_close(nbd);
742 nbd_size_clear(nbd, bdev);
743 device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
745 mutex_lock(&nbd->config_lock);
746 nbd->task_recv = NULL;
748 clear_bit(NBD_RUNNING, &nbd->runtime_flags);
749 nbd_clear_sock(nbd, bdev);
751 /* user requested, ignore socket errors */
752 if (test_bit(NBD_DISCONNECT_REQUESTED, &nbd->runtime_flags))
754 if (test_bit(NBD_TIMEDOUT, &nbd->runtime_flags))
761 /* Must be called with config_lock held */
762 static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
763 unsigned int cmd, unsigned long arg)
767 return nbd_disconnect(nbd, bdev);
769 return nbd_clear_sock(nbd, bdev);
771 return nbd_add_socket(nbd, bdev, arg);
772 case NBD_SET_BLKSIZE:
773 nbd_size_set(nbd, bdev, arg,
774 div_s64(nbd->bytesize, arg));
777 nbd_size_set(nbd, bdev, nbd->blksize,
778 div_s64(arg, nbd->blksize));
780 case NBD_SET_SIZE_BLOCKS:
781 nbd_size_set(nbd, bdev, nbd->blksize, arg);
783 case NBD_SET_TIMEOUT:
784 nbd->tag_set.timeout = arg * HZ;
791 return nbd_start_device(nbd, bdev);
794 * This is for compatibility only. The queue is always cleared
795 * by NBD_DO_IT or NBD_CLEAR_SOCK.
798 case NBD_PRINT_DEBUG:
800 * For compatibility only, we no longer keep a list of
801 * outstanding requests.
808 static int nbd_ioctl(struct block_device *bdev, fmode_t mode,
809 unsigned int cmd, unsigned long arg)
811 struct nbd_device *nbd = bdev->bd_disk->private_data;
814 if (!capable(CAP_SYS_ADMIN))
817 BUG_ON(nbd->magic != NBD_MAGIC);
819 mutex_lock(&nbd->config_lock);
820 error = __nbd_ioctl(bdev, nbd, cmd, arg);
821 mutex_unlock(&nbd->config_lock);
826 static const struct block_device_operations nbd_fops =
828 .owner = THIS_MODULE,
830 .compat_ioctl = nbd_ioctl,
833 #if IS_ENABLED(CONFIG_DEBUG_FS)
835 static int nbd_dbg_tasks_show(struct seq_file *s, void *unused)
837 struct nbd_device *nbd = s->private;
840 seq_printf(s, "recv: %d\n", task_pid_nr(nbd->task_recv));
845 static int nbd_dbg_tasks_open(struct inode *inode, struct file *file)
847 return single_open(file, nbd_dbg_tasks_show, inode->i_private);
850 static const struct file_operations nbd_dbg_tasks_ops = {
851 .open = nbd_dbg_tasks_open,
854 .release = single_release,
857 static int nbd_dbg_flags_show(struct seq_file *s, void *unused)
859 struct nbd_device *nbd = s->private;
860 u32 flags = nbd->flags;
862 seq_printf(s, "Hex: 0x%08x\n\n", flags);
864 seq_puts(s, "Known flags:\n");
866 if (flags & NBD_FLAG_HAS_FLAGS)
867 seq_puts(s, "NBD_FLAG_HAS_FLAGS\n");
868 if (flags & NBD_FLAG_READ_ONLY)
869 seq_puts(s, "NBD_FLAG_READ_ONLY\n");
870 if (flags & NBD_FLAG_SEND_FLUSH)
871 seq_puts(s, "NBD_FLAG_SEND_FLUSH\n");
872 if (flags & NBD_FLAG_SEND_TRIM)
873 seq_puts(s, "NBD_FLAG_SEND_TRIM\n");
878 static int nbd_dbg_flags_open(struct inode *inode, struct file *file)
880 return single_open(file, nbd_dbg_flags_show, inode->i_private);
883 static const struct file_operations nbd_dbg_flags_ops = {
884 .open = nbd_dbg_flags_open,
887 .release = single_release,
890 static int nbd_dev_dbg_init(struct nbd_device *nbd)
897 dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir);
899 dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s'\n",
905 debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_ops);
906 debugfs_create_u64("size_bytes", 0444, dir, &nbd->bytesize);
907 debugfs_create_u32("timeout", 0444, dir, &nbd->tag_set.timeout);
908 debugfs_create_u64("blocksize", 0444, dir, &nbd->blksize);
909 debugfs_create_file("flags", 0444, dir, nbd, &nbd_dbg_flags_ops);
914 static void nbd_dev_dbg_close(struct nbd_device *nbd)
916 debugfs_remove_recursive(nbd->dbg_dir);
919 static int nbd_dbg_init(void)
921 struct dentry *dbg_dir;
923 dbg_dir = debugfs_create_dir("nbd", NULL);
927 nbd_dbg_dir = dbg_dir;
932 static void nbd_dbg_close(void)
934 debugfs_remove_recursive(nbd_dbg_dir);
937 #else /* IS_ENABLED(CONFIG_DEBUG_FS) */
939 static int nbd_dev_dbg_init(struct nbd_device *nbd)
944 static void nbd_dev_dbg_close(struct nbd_device *nbd)
948 static int nbd_dbg_init(void)
953 static void nbd_dbg_close(void)
959 static int nbd_init_request(void *data, struct request *rq,
960 unsigned int hctx_idx, unsigned int request_idx,
961 unsigned int numa_node)
963 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq);
968 static struct blk_mq_ops nbd_mq_ops = {
969 .queue_rq = nbd_queue_rq,
970 .init_request = nbd_init_request,
971 .timeout = nbd_xmit_timeout,
974 static void nbd_dev_remove(struct nbd_device *nbd)
976 struct gendisk *disk = nbd->disk;
980 blk_cleanup_queue(disk->queue);
981 blk_mq_free_tag_set(&nbd->tag_set);
987 static int nbd_dev_add(int index)
989 struct nbd_device *nbd;
990 struct gendisk *disk;
991 struct request_queue *q;
994 nbd = kzalloc(sizeof(struct nbd_device), GFP_KERNEL);
998 disk = alloc_disk(1 << part_shift);
1003 err = idr_alloc(&nbd_index_idr, nbd, index, index + 1,
1008 err = idr_alloc(&nbd_index_idr, nbd, 0, 0, GFP_KERNEL);
1016 nbd->tag_set.ops = &nbd_mq_ops;
1017 nbd->tag_set.nr_hw_queues = 1;
1018 nbd->tag_set.queue_depth = 128;
1019 nbd->tag_set.numa_node = NUMA_NO_NODE;
1020 nbd->tag_set.cmd_size = sizeof(struct nbd_cmd);
1021 nbd->tag_set.flags = BLK_MQ_F_SHOULD_MERGE |
1022 BLK_MQ_F_SG_MERGE | BLK_MQ_F_BLOCKING;
1023 nbd->tag_set.driver_data = nbd;
1025 err = blk_mq_alloc_tag_set(&nbd->tag_set);
1029 q = blk_mq_init_queue(&nbd->tag_set);
1037 * Tell the block layer that we are not a rotational device
1039 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue);
1040 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, disk->queue);
1041 disk->queue->limits.discard_granularity = 512;
1042 blk_queue_max_discard_sectors(disk->queue, UINT_MAX);
1043 disk->queue->limits.discard_zeroes_data = 0;
1044 blk_queue_max_hw_sectors(disk->queue, 65536);
1045 disk->queue->limits.max_sectors = 256;
1047 nbd->magic = NBD_MAGIC;
1048 mutex_init(&nbd->config_lock);
1049 disk->major = NBD_MAJOR;
1050 disk->first_minor = index << part_shift;
1051 disk->fops = &nbd_fops;
1052 disk->private_data = nbd;
1053 sprintf(disk->disk_name, "nbd%d", index);
1054 init_waitqueue_head(&nbd->recv_wq);
1060 blk_mq_free_tag_set(&nbd->tag_set);
1062 idr_remove(&nbd_index_idr, index);
1072 * And here should be modules and kernel interface
1073 * (Just smiley confuses emacs :-)
1076 static int __init nbd_init(void)
1080 BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
1083 printk(KERN_ERR "nbd: max_part must be >= 0\n");
1089 part_shift = fls(max_part);
1092 * Adjust max_part according to part_shift as it is exported
1093 * to user space so that user can know the max number of
1094 * partition kernel should be able to manage.
1096 * Note that -1 is required because partition 0 is reserved
1097 * for the whole disk.
1099 max_part = (1UL << part_shift) - 1;
1102 if ((1UL << part_shift) > DISK_MAX_PARTS)
1105 if (nbds_max > 1UL << (MINORBITS - part_shift))
1107 recv_workqueue = alloc_workqueue("knbd-recv",
1108 WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
1109 if (!recv_workqueue)
1112 if (register_blkdev(NBD_MAJOR, "nbd")) {
1113 destroy_workqueue(recv_workqueue);
1119 mutex_lock(&nbd_index_mutex);
1120 for (i = 0; i < nbds_max; i++)
1122 mutex_unlock(&nbd_index_mutex);
1126 static int nbd_exit_cb(int id, void *ptr, void *data)
1128 struct nbd_device *nbd = ptr;
1129 nbd_dev_remove(nbd);
1133 static void __exit nbd_cleanup(void)
1137 idr_for_each(&nbd_index_idr, &nbd_exit_cb, NULL);
1138 idr_destroy(&nbd_index_idr);
1139 destroy_workqueue(recv_workqueue);
1140 unregister_blkdev(NBD_MAJOR, "nbd");
1143 module_init(nbd_init);
1144 module_exit(nbd_cleanup);
1146 MODULE_DESCRIPTION("Network Block Device");
1147 MODULE_LICENSE("GPL");
1149 module_param(nbds_max, int, 0444);
1150 MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
1151 module_param(max_part, int, 0444);
1152 MODULE_PARM_DESC(max_part, "number of partitions per device (default: 0)");