| /* |
| * Network block device - make block devices work over TCP |
| * |
| * Note that you can not swap over this thing, yet. Seems to work but |
| * deadlocks sometimes - you can not swap over TCP in general. |
| * |
| * Copyright 1997-2000, 2008 Pavel Machek <pavel@ucw.cz> |
| * Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com> |
| * |
| * This file is released under GPLv2 or later. |
| * |
| * (part of code stolen from loop.c) |
| */ |
| |
| #include <linux/major.h> |
| |
| #include <linux/blkdev.h> |
| #include <linux/module.h> |
| #include <linux/init.h> |
| #include <linux/sched.h> |
| #include <linux/fs.h> |
| #include <linux/bio.h> |
| #include <linux/stat.h> |
| #include <linux/errno.h> |
| #include <linux/file.h> |
| #include <linux/ioctl.h> |
| #include <linux/mutex.h> |
| #include <linux/compiler.h> |
| #include <linux/err.h> |
| #include <linux/kernel.h> |
| #include <linux/slab.h> |
| #include <net/sock.h> |
| #include <linux/net.h> |
| #include <linux/kthread.h> |
| #include <linux/types.h> |
| #include <linux/debugfs.h> |
| #include <linux/blk-mq.h> |
| |
| #include <asm/uaccess.h> |
| #include <asm/types.h> |
| |
| #include <linux/nbd.h> |
| |
| struct nbd_sock { |
| struct socket *sock; |
| struct mutex tx_lock; |
| }; |
| |
| #define NBD_TIMEDOUT 0 |
| #define NBD_DISCONNECT_REQUESTED 1 |
| #define NBD_DISCONNECTED 2 |
| #define NBD_RUNNING 3 |
| |
| struct nbd_device { |
| u32 flags; |
| unsigned long runtime_flags; |
| struct nbd_sock **socks; |
| int magic; |
| |
| struct blk_mq_tag_set tag_set; |
| |
| struct mutex config_lock; |
| struct gendisk *disk; |
| int num_connections; |
| atomic_t recv_threads; |
| wait_queue_head_t recv_wq; |
| loff_t blksize; |
| loff_t bytesize; |
| |
| struct task_struct *task_recv; |
| struct task_struct *task_setup; |
| |
| #if IS_ENABLED(CONFIG_DEBUG_FS) |
| struct dentry *dbg_dir; |
| #endif |
| }; |
| |
| struct nbd_cmd { |
| struct nbd_device *nbd; |
| struct completion send_complete; |
| }; |
| |
| #if IS_ENABLED(CONFIG_DEBUG_FS) |
| static struct dentry *nbd_dbg_dir; |
| #endif |
| |
| #define nbd_name(nbd) ((nbd)->disk->disk_name) |
| |
| #define NBD_MAGIC 0x68797548 |
| |
| static unsigned int nbds_max = 16; |
| static struct nbd_device *nbd_dev; |
| static int max_part; |
| |
| static inline struct device *nbd_to_dev(struct nbd_device *nbd) |
| { |
| return disk_to_dev(nbd->disk); |
| } |
| |
| static bool nbd_is_connected(struct nbd_device *nbd) |
| { |
| return !!nbd->task_recv; |
| } |
| |
| static const char *nbdcmd_to_ascii(int cmd) |
| { |
| switch (cmd) { |
| case NBD_CMD_READ: return "read"; |
| case NBD_CMD_WRITE: return "write"; |
| case NBD_CMD_DISC: return "disconnect"; |
| case NBD_CMD_FLUSH: return "flush"; |
| case NBD_CMD_TRIM: return "trim/discard"; |
| } |
| return "invalid"; |
| } |
| |
| static int nbd_size_clear(struct nbd_device *nbd, struct block_device *bdev) |
| { |
| bdev->bd_inode->i_size = 0; |
| set_capacity(nbd->disk, 0); |
| kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE); |
| |
| return 0; |
| } |
| |
| static void nbd_size_update(struct nbd_device *nbd, struct block_device *bdev) |
| { |
| if (!nbd_is_connected(nbd)) |
| return; |
| |
| bdev->bd_inode->i_size = nbd->bytesize; |
| set_capacity(nbd->disk, nbd->bytesize >> 9); |
| kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE); |
| } |
| |
| static int nbd_size_set(struct nbd_device *nbd, struct block_device *bdev, |
| loff_t blocksize, loff_t nr_blocks) |
| { |
| int ret; |
| |
| ret = set_blocksize(bdev, blocksize); |
| if (ret) |
| return ret; |
| |
| nbd->blksize = blocksize; |
| nbd->bytesize = blocksize * nr_blocks; |
| |
| nbd_size_update(nbd, bdev); |
| |
| return 0; |
| } |
| |
| static void nbd_end_request(struct nbd_cmd *cmd) |
| { |
| struct nbd_device *nbd = cmd->nbd; |
| struct request *req = blk_mq_rq_from_pdu(cmd); |
| int error = req->errors ? -EIO : 0; |
| |
| dev_dbg(nbd_to_dev(nbd), "request %p: %s\n", cmd, |
| error ? "failed" : "done"); |
| |
| blk_mq_complete_request(req, error); |
| } |
| |
| /* |
| * Forcibly shutdown the socket causing all listeners to error |
| */ |
| static void sock_shutdown(struct nbd_device *nbd) |
| { |
| int i; |
| |
| if (nbd->num_connections == 0) |
| return; |
| if (test_and_set_bit(NBD_DISCONNECTED, &nbd->runtime_flags)) |
| return; |
| |
| for (i = 0; i < nbd->num_connections; i++) { |
| struct nbd_sock *nsock = nbd->socks[i]; |
| mutex_lock(&nsock->tx_lock); |
| kernel_sock_shutdown(nsock->sock, SHUT_RDWR); |
| mutex_unlock(&nsock->tx_lock); |
| } |
| dev_warn(disk_to_dev(nbd->disk), "shutting down sockets\n"); |
| } |
| |
| static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req, |
| bool reserved) |
| { |
| struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req); |
| struct nbd_device *nbd = cmd->nbd; |
| |
| dev_err(nbd_to_dev(nbd), "Connection timed out, shutting down connection\n"); |
| set_bit(NBD_TIMEDOUT, &nbd->runtime_flags); |
| req->errors++; |
| |
| /* |
| * If our disconnect packet times out then we're already holding the |
| * config_lock and could deadlock here, so just set an error and return, |
| * we'll handle shutting everything down later. |
| */ |
| if (req->cmd_type == REQ_TYPE_DRV_PRIV) |
| return BLK_EH_HANDLED; |
| mutex_lock(&nbd->config_lock); |
| sock_shutdown(nbd); |
| mutex_unlock(&nbd->config_lock); |
| return BLK_EH_HANDLED; |
| } |
| |
| /* |
| * Send or receive packet. |
| */ |
| static int sock_xmit(struct nbd_device *nbd, int index, int send, void *buf, |
| int size, int msg_flags) |
| { |
| struct socket *sock = nbd->socks[index]->sock; |
| int result; |
| struct msghdr msg; |
| struct kvec iov; |
| unsigned long pflags = current->flags; |
| |
| if (unlikely(!sock)) { |
| dev_err_ratelimited(disk_to_dev(nbd->disk), |
| "Attempted %s on closed socket in sock_xmit\n", |
| (send ? "send" : "recv")); |
| return -EINVAL; |
| } |
| |
| current->flags |= PF_MEMALLOC; |
| do { |
| sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC; |
| iov.iov_base = buf; |
| iov.iov_len = size; |
| msg.msg_name = NULL; |
| msg.msg_namelen = 0; |
| msg.msg_control = NULL; |
| msg.msg_controllen = 0; |
| msg.msg_flags = msg_flags | MSG_NOSIGNAL; |
| |
| if (send) |
| result = kernel_sendmsg(sock, &msg, &iov, 1, size); |
| else |
| result = kernel_recvmsg(sock, &msg, &iov, 1, size, |
| msg.msg_flags); |
| |
| if (result <= 0) { |
| if (result == 0) |
| result = -EPIPE; /* short read */ |
| break; |
| } |
| size -= result; |
| buf += result; |
| } while (size > 0); |
| |
| tsk_restore_flags(current, pflags, PF_MEMALLOC); |
| |
| return result; |
| } |
| |
| static inline int sock_send_bvec(struct nbd_device *nbd, int index, |
| struct bio_vec *bvec, int flags) |
| { |
| int result; |
| void *kaddr = kmap(bvec->bv_page); |
| result = sock_xmit(nbd, index, 1, kaddr + bvec->bv_offset, |
| bvec->bv_len, flags); |
| kunmap(bvec->bv_page); |
| return result; |
| } |
| |
| /* always call with the tx_lock held */ |
| static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index) |
| { |
| struct request *req = blk_mq_rq_from_pdu(cmd); |
| int result, flags; |
| struct nbd_request request; |
| unsigned long size = blk_rq_bytes(req); |
| struct bio *bio; |
| u32 type; |
| u32 tag = blk_mq_unique_tag(req); |
| |
| if (req_op(req) == REQ_OP_DISCARD) |
| type = NBD_CMD_TRIM; |
| else if (req_op(req) == REQ_OP_FLUSH) |
| type = NBD_CMD_FLUSH; |
| else if (rq_data_dir(req) == WRITE) |
| type = NBD_CMD_WRITE; |
| else |
| type = NBD_CMD_READ; |
| |
| memset(&request, 0, sizeof(request)); |
| request.magic = htonl(NBD_REQUEST_MAGIC); |
| request.type = htonl(type); |
| if (type != NBD_CMD_FLUSH) { |
| request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9); |
| request.len = htonl(size); |
| } |
| memcpy(request.handle, &tag, sizeof(tag)); |
| |
| dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n", |
| cmd, nbdcmd_to_ascii(type), |
| (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req)); |
| result = sock_xmit(nbd, index, 1, &request, sizeof(request), |
| (type == NBD_CMD_WRITE) ? MSG_MORE : 0); |
| if (result <= 0) { |
| dev_err_ratelimited(disk_to_dev(nbd->disk), |
| "Send control failed (result %d)\n", result); |
| return -EIO; |
| } |
| |
| if (type != NBD_CMD_WRITE) |
| return 0; |
| |
| flags = 0; |
| bio = req->bio; |
| while (bio) { |
| struct bio *next = bio->bi_next; |
| struct bvec_iter iter; |
| struct bio_vec bvec; |
| |
| bio_for_each_segment(bvec, bio, iter) { |
| bool is_last = !next && bio_iter_last(bvec, iter); |
| |
| if (is_last) |
| flags = MSG_MORE; |
| dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n", |
| cmd, bvec.bv_len); |
| result = sock_send_bvec(nbd, index, &bvec, flags); |
| if (result <= 0) { |
| dev_err(disk_to_dev(nbd->disk), |
| "Send data failed (result %d)\n", |
| result); |
| return -EIO; |
| } |
| /* |
| * The completion might already have come in, |
| * so break for the last one instead of letting |
| * the iterator do it. This prevents use-after-free |
| * of the bio. |
| */ |
| if (is_last) |
| break; |
| } |
| bio = next; |
| } |
| return 0; |
| } |
| |
| static inline int sock_recv_bvec(struct nbd_device *nbd, int index, |
| struct bio_vec *bvec) |
| { |
| int result; |
| void *kaddr = kmap(bvec->bv_page); |
| result = sock_xmit(nbd, index, 0, kaddr + bvec->bv_offset, |
| bvec->bv_len, MSG_WAITALL); |
| kunmap(bvec->bv_page); |
| return result; |
| } |
| |
| /* NULL returned = something went wrong, inform userspace */ |
| static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index) |
| { |
| int result; |
| struct nbd_reply reply; |
| struct nbd_cmd *cmd; |
| struct request *req = NULL; |
| u16 hwq; |
| u32 tag; |
| |
| reply.magic = 0; |
| result = sock_xmit(nbd, index, 0, &reply, sizeof(reply), MSG_WAITALL); |
| if (result <= 0) { |
| if (!test_bit(NBD_DISCONNECTED, &nbd->runtime_flags) && |
| !test_bit(NBD_DISCONNECT_REQUESTED, &nbd->runtime_flags)) |
| dev_err(disk_to_dev(nbd->disk), |
| "Receive control failed (result %d)\n", result); |
| return ERR_PTR(result); |
| } |
| |
| if (ntohl(reply.magic) != NBD_REPLY_MAGIC) { |
| dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n", |
| (unsigned long)ntohl(reply.magic)); |
| return ERR_PTR(-EPROTO); |
| } |
| |
| memcpy(&tag, reply.handle, sizeof(u32)); |
| |
| hwq = blk_mq_unique_tag_to_hwq(tag); |
| if (hwq < nbd->tag_set.nr_hw_queues) |
| req = blk_mq_tag_to_rq(nbd->tag_set.tags[hwq], |
| blk_mq_unique_tag_to_tag(tag)); |
| if (!req || !blk_mq_request_started(req)) { |
| dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%d) %p\n", |
| tag, req); |
| return ERR_PTR(-ENOENT); |
| } |
| cmd = blk_mq_rq_to_pdu(req); |
| if (ntohl(reply.error)) { |
| dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n", |
| ntohl(reply.error)); |
| req->errors++; |
| return cmd; |
| } |
| |
| dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", cmd); |
| if (rq_data_dir(req) != WRITE) { |
| struct req_iterator iter; |
| struct bio_vec bvec; |
| |
| rq_for_each_segment(bvec, req, iter) { |
| result = sock_recv_bvec(nbd, index, &bvec); |
| if (result <= 0) { |
| dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n", |
| result); |
| req->errors++; |
| return cmd; |
| } |
| dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n", |
| cmd, bvec.bv_len); |
| } |
| } else { |
| /* See the comment in nbd_queue_rq. */ |
| wait_for_completion(&cmd->send_complete); |
| } |
| return cmd; |
| } |
| |
| static ssize_t pid_show(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| struct gendisk *disk = dev_to_disk(dev); |
| struct nbd_device *nbd = (struct nbd_device *)disk->private_data; |
| |
| return sprintf(buf, "%d\n", task_pid_nr(nbd->task_recv)); |
| } |
| |
| static struct device_attribute pid_attr = { |
| .attr = { .name = "pid", .mode = S_IRUGO}, |
| .show = pid_show, |
| }; |
| |
| struct recv_thread_args { |
| struct work_struct work; |
| struct nbd_device *nbd; |
| int index; |
| }; |
| |
| static void recv_work(struct work_struct *work) |
| { |
| struct recv_thread_args *args = container_of(work, |
| struct recv_thread_args, |
| work); |
| struct nbd_device *nbd = args->nbd; |
| struct nbd_cmd *cmd; |
| int ret = 0; |
| |
| BUG_ON(nbd->magic != NBD_MAGIC); |
| while (1) { |
| cmd = nbd_read_stat(nbd, args->index); |
| if (IS_ERR(cmd)) { |
| ret = PTR_ERR(cmd); |
| break; |
| } |
| |
| nbd_end_request(cmd); |
| } |
| |
| /* |
| * We got an error, shut everybody down if this wasn't the result of a |
| * disconnect request. |
| */ |
| if (ret && !test_bit(NBD_DISCONNECT_REQUESTED, &nbd->runtime_flags)) |
| sock_shutdown(nbd); |
| atomic_dec(&nbd->recv_threads); |
| wake_up(&nbd->recv_wq); |
| } |
| |
| static void nbd_clear_req(struct request *req, void *data, bool reserved) |
| { |
| struct nbd_cmd *cmd; |
| |
| if (!blk_mq_request_started(req)) |
| return; |
| cmd = blk_mq_rq_to_pdu(req); |
| req->errors++; |
| nbd_end_request(cmd); |
| } |
| |
| static void nbd_clear_que(struct nbd_device *nbd) |
| { |
| BUG_ON(nbd->magic != NBD_MAGIC); |
| |
| blk_mq_tagset_busy_iter(&nbd->tag_set, nbd_clear_req, NULL); |
| dev_dbg(disk_to_dev(nbd->disk), "queue cleared\n"); |
| } |
| |
| |
| static void nbd_handle_cmd(struct nbd_cmd *cmd, int index) |
| { |
| struct request *req = blk_mq_rq_from_pdu(cmd); |
| struct nbd_device *nbd = cmd->nbd; |
| struct nbd_sock *nsock; |
| |
| if (index >= nbd->num_connections) { |
| dev_err_ratelimited(disk_to_dev(nbd->disk), |
| "Attempted send on invalid socket\n"); |
| goto error_out; |
| } |
| |
| if (test_bit(NBD_DISCONNECTED, &nbd->runtime_flags)) { |
| dev_err_ratelimited(disk_to_dev(nbd->disk), |
| "Attempted send on closed socket\n"); |
| goto error_out; |
| } |
| |
| if (req->cmd_type != REQ_TYPE_FS && |
| req->cmd_type != REQ_TYPE_DRV_PRIV) |
| goto error_out; |
| |
| if (req->cmd_type == REQ_TYPE_FS && |
| rq_data_dir(req) == WRITE && |
| (nbd->flags & NBD_FLAG_READ_ONLY)) { |
| dev_err_ratelimited(disk_to_dev(nbd->disk), |
| "Write on read-only\n"); |
| goto error_out; |
| } |
| |
| req->errors = 0; |
| |
| nsock = nbd->socks[index]; |
| mutex_lock(&nsock->tx_lock); |
| if (unlikely(!nsock->sock)) { |
| mutex_unlock(&nsock->tx_lock); |
| dev_err_ratelimited(disk_to_dev(nbd->disk), |
| "Attempted send on closed socket\n"); |
| goto error_out; |
| } |
| |
| if (nbd_send_cmd(nbd, cmd, index) != 0) { |
| dev_err_ratelimited(disk_to_dev(nbd->disk), |
| "Request send failed\n"); |
| req->errors++; |
| nbd_end_request(cmd); |
| } |
| |
| mutex_unlock(&nsock->tx_lock); |
| |
| return; |
| |
| error_out: |
| req->errors++; |
| nbd_end_request(cmd); |
| } |
| |
| static int nbd_queue_rq(struct blk_mq_hw_ctx *hctx, |
| const struct blk_mq_queue_data *bd) |
| { |
| struct nbd_cmd *cmd = blk_mq_rq_to_pdu(bd->rq); |
| |
| /* |
| * Since we look at the bio's to send the request over the network we |
| * need to make sure the completion work doesn't mark this request done |
| * before we are done doing our send. This keeps us from dereferencing |
| * freed data if we have particularly fast completions (ie we get the |
| * completion before we exit sock_xmit on the last bvec) or in the case |
| * that the server is misbehaving (or there was an error) before we're |
| * done sending everything over the wire. |
| */ |
| init_completion(&cmd->send_complete); |
| blk_mq_start_request(bd->rq); |
| nbd_handle_cmd(cmd, hctx->queue_num); |
| complete(&cmd->send_complete); |
| |
| return BLK_MQ_RQ_QUEUE_OK; |
| } |
| |
| static int nbd_add_socket(struct nbd_device *nbd, struct socket *sock) |
| { |
| struct nbd_sock **socks; |
| struct nbd_sock *nsock; |
| |
| if (!nbd->task_setup) |
| nbd->task_setup = current; |
| if (nbd->task_setup != current) { |
| dev_err(disk_to_dev(nbd->disk), |
| "Device being setup by another task"); |
| return -EINVAL; |
| } |
| |
| socks = krealloc(nbd->socks, (nbd->num_connections + 1) * |
| sizeof(struct nbd_sock *), GFP_KERNEL); |
| if (!socks) |
| return -ENOMEM; |
| nsock = kzalloc(sizeof(struct nbd_sock), GFP_KERNEL); |
| if (!nsock) |
| return -ENOMEM; |
| |
| nbd->socks = socks; |
| |
| mutex_init(&nsock->tx_lock); |
| nsock->sock = sock; |
| socks[nbd->num_connections++] = nsock; |
| |
| return 0; |
| } |
| |
| /* Reset all properties of an NBD device */ |
| static void nbd_reset(struct nbd_device *nbd) |
| { |
| int i; |
| |
| for (i = 0; i < nbd->num_connections; i++) |
| kfree(nbd->socks[i]); |
| kfree(nbd->socks); |
| nbd->socks = NULL; |
| nbd->runtime_flags = 0; |
| nbd->blksize = 1024; |
| nbd->bytesize = 0; |
| set_capacity(nbd->disk, 0); |
| nbd->flags = 0; |
| nbd->tag_set.timeout = 0; |
| nbd->num_connections = 0; |
| nbd->task_setup = NULL; |
| queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue); |
| } |
| |
| static void nbd_bdev_reset(struct block_device *bdev) |
| { |
| set_device_ro(bdev, false); |
| bdev->bd_inode->i_size = 0; |
| if (max_part > 0) { |
| blkdev_reread_part(bdev); |
| bdev->bd_invalidated = 1; |
| } |
| } |
| |
| static void nbd_parse_flags(struct nbd_device *nbd, struct block_device *bdev) |
| { |
| if (nbd->flags & NBD_FLAG_READ_ONLY) |
| set_device_ro(bdev, true); |
| if (nbd->flags & NBD_FLAG_SEND_TRIM) |
| queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue); |
| if (nbd->flags & NBD_FLAG_SEND_FLUSH) |
| blk_queue_write_cache(nbd->disk->queue, true, false); |
| else |
| blk_queue_write_cache(nbd->disk->queue, false, false); |
| } |
| |
| static void send_disconnects(struct nbd_device *nbd) |
| { |
| struct nbd_request request = {}; |
| int i, ret; |
| |
| request.magic = htonl(NBD_REQUEST_MAGIC); |
| request.type = htonl(NBD_CMD_DISC); |
| |
| for (i = 0; i < nbd->num_connections; i++) { |
| ret = sock_xmit(nbd, i, 1, &request, sizeof(request), 0); |
| if (ret <= 0) |
| dev_err(disk_to_dev(nbd->disk), |
| "Send disconnect failed %d\n", ret); |
| } |
| } |
| |
| static int nbd_dev_dbg_init(struct nbd_device *nbd); |
| static void nbd_dev_dbg_close(struct nbd_device *nbd); |
| |
| /* Must be called with config_lock held */ |
| static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd, |
| unsigned int cmd, unsigned long arg) |
| { |
| switch (cmd) { |
| case NBD_DISCONNECT: { |
| dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n"); |
| if (!nbd->socks) |
| return -EINVAL; |
| |
| mutex_unlock(&nbd->config_lock); |
| fsync_bdev(bdev); |
| mutex_lock(&nbd->config_lock); |
| |
| /* Check again after getting mutex back. */ |
| if (!nbd->socks) |
| return -EINVAL; |
| |
| if (!test_and_set_bit(NBD_DISCONNECT_REQUESTED, |
| &nbd->runtime_flags)) |
| send_disconnects(nbd); |
| return 0; |
| } |
| |
| case NBD_CLEAR_SOCK: |
| sock_shutdown(nbd); |
| nbd_clear_que(nbd); |
| kill_bdev(bdev); |
| nbd_bdev_reset(bdev); |
| /* |
| * We want to give the run thread a chance to wait for everybody |
| * to clean up and then do it's own cleanup. |
| */ |
| if (!test_bit(NBD_RUNNING, &nbd->runtime_flags)) { |
| int i; |
| |
| for (i = 0; i < nbd->num_connections; i++) |
| kfree(nbd->socks[i]); |
| kfree(nbd->socks); |
| nbd->socks = NULL; |
| nbd->num_connections = 0; |
| nbd->task_setup = NULL; |
| } |
| return 0; |
| |
| case NBD_SET_SOCK: { |
| int err; |
| struct socket *sock = sockfd_lookup(arg, &err); |
| |
| if (!sock) |
| return err; |
| |
| err = nbd_add_socket(nbd, sock); |
| if (!err && max_part) |
| bdev->bd_invalidated = 1; |
| |
| return err; |
| } |
| |
| case NBD_SET_BLKSIZE: { |
| loff_t bsize = div_s64(nbd->bytesize, arg); |
| |
| return nbd_size_set(nbd, bdev, arg, bsize); |
| } |
| |
| case NBD_SET_SIZE: |
| return nbd_size_set(nbd, bdev, nbd->blksize, |
| div_s64(arg, nbd->blksize)); |
| |
| case NBD_SET_SIZE_BLOCKS: |
| return nbd_size_set(nbd, bdev, nbd->blksize, arg); |
| |
| case NBD_SET_TIMEOUT: |
| nbd->tag_set.timeout = arg * HZ; |
| return 0; |
| |
| case NBD_SET_FLAGS: |
| nbd->flags = arg; |
| return 0; |
| |
| case NBD_DO_IT: { |
| struct recv_thread_args *args; |
| int num_connections = nbd->num_connections; |
| int error = 0, i; |
| |
| if (nbd->task_recv) |
| return -EBUSY; |
| if (!nbd->socks) |
| return -EINVAL; |
| if (num_connections > 1 && |
| !(nbd->flags & NBD_FLAG_CAN_MULTI_CONN)) { |
| dev_err(disk_to_dev(nbd->disk), "server does not support multiple connections per device.\n"); |
| error = -EINVAL; |
| goto out_err; |
| } |
| |
| set_bit(NBD_RUNNING, &nbd->runtime_flags); |
| blk_mq_update_nr_hw_queues(&nbd->tag_set, nbd->num_connections); |
| args = kcalloc(num_connections, sizeof(*args), GFP_KERNEL); |
| if (!args) { |
| error = -ENOMEM; |
| goto out_err; |
| } |
| nbd->task_recv = current; |
| mutex_unlock(&nbd->config_lock); |
| |
| nbd_parse_flags(nbd, bdev); |
| |
| error = device_create_file(disk_to_dev(nbd->disk), &pid_attr); |
| if (error) { |
| dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n"); |
| goto out_recv; |
| } |
| |
| nbd_size_update(nbd, bdev); |
| |
| nbd_dev_dbg_init(nbd); |
| for (i = 0; i < num_connections; i++) { |
| sk_set_memalloc(nbd->socks[i]->sock->sk); |
| atomic_inc(&nbd->recv_threads); |
| INIT_WORK(&args[i].work, recv_work); |
| args[i].nbd = nbd; |
| args[i].index = i; |
| queue_work(system_long_wq, &args[i].work); |
| } |
| wait_event_interruptible(nbd->recv_wq, |
| atomic_read(&nbd->recv_threads) == 0); |
| for (i = 0; i < num_connections; i++) |
| flush_work(&args[i].work); |
| nbd_dev_dbg_close(nbd); |
| nbd_size_clear(nbd, bdev); |
| device_remove_file(disk_to_dev(nbd->disk), &pid_attr); |
| out_recv: |
| mutex_lock(&nbd->config_lock); |
| nbd->task_recv = NULL; |
| out_err: |
| sock_shutdown(nbd); |
| nbd_clear_que(nbd); |
| kill_bdev(bdev); |
| nbd_bdev_reset(bdev); |
| |
| /* user requested, ignore socket errors */ |
| if (test_bit(NBD_DISCONNECT_REQUESTED, &nbd->runtime_flags)) |
| error = 0; |
| if (test_bit(NBD_TIMEDOUT, &nbd->runtime_flags)) |
| error = -ETIMEDOUT; |
| |
| nbd_reset(nbd); |
| return error; |
| } |
| |
| case NBD_CLEAR_QUE: |
| /* |
| * This is for compatibility only. The queue is always cleared |
| * by NBD_DO_IT or NBD_CLEAR_SOCK. |
| */ |
| return 0; |
| |
| case NBD_PRINT_DEBUG: |
| /* |
| * For compatibility only, we no longer keep a list of |
| * outstanding requests. |
| */ |
| return 0; |
| } |
| return -ENOTTY; |
| } |
| |
| static int nbd_ioctl(struct block_device *bdev, fmode_t mode, |
| unsigned int cmd, unsigned long arg) |
| { |
| struct nbd_device *nbd = bdev->bd_disk->private_data; |
| int error; |
| |
| if (!capable(CAP_SYS_ADMIN)) |
| return -EPERM; |
| |
| BUG_ON(nbd->magic != NBD_MAGIC); |
| |
| mutex_lock(&nbd->config_lock); |
| error = __nbd_ioctl(bdev, nbd, cmd, arg); |
| mutex_unlock(&nbd->config_lock); |
| |
| return error; |
| } |
| |
| static const struct block_device_operations nbd_fops = |
| { |
| .owner = THIS_MODULE, |
| .ioctl = nbd_ioctl, |
| .compat_ioctl = nbd_ioctl, |
| }; |
| |
| #if IS_ENABLED(CONFIG_DEBUG_FS) |
| |
| static int nbd_dbg_tasks_show(struct seq_file *s, void *unused) |
| { |
| struct nbd_device *nbd = s->private; |
| |
| if (nbd->task_recv) |
| seq_printf(s, "recv: %d\n", task_pid_nr(nbd->task_recv)); |
| |
| return 0; |
| } |
| |
| static int nbd_dbg_tasks_open(struct inode *inode, struct file *file) |
| { |
| return single_open(file, nbd_dbg_tasks_show, inode->i_private); |
| } |
| |
| static const struct file_operations nbd_dbg_tasks_ops = { |
| .open = nbd_dbg_tasks_open, |
| .read = seq_read, |
| .llseek = seq_lseek, |
| .release = single_release, |
| }; |
| |
| static int nbd_dbg_flags_show(struct seq_file *s, void *unused) |
| { |
| struct nbd_device *nbd = s->private; |
| u32 flags = nbd->flags; |
| |
| seq_printf(s, "Hex: 0x%08x\n\n", flags); |
| |
| seq_puts(s, "Known flags:\n"); |
| |
| if (flags & NBD_FLAG_HAS_FLAGS) |
| seq_puts(s, "NBD_FLAG_HAS_FLAGS\n"); |
| if (flags & NBD_FLAG_READ_ONLY) |
| seq_puts(s, "NBD_FLAG_READ_ONLY\n"); |
| if (flags & NBD_FLAG_SEND_FLUSH) |
| seq_puts(s, "NBD_FLAG_SEND_FLUSH\n"); |
| if (flags & NBD_FLAG_SEND_TRIM) |
| seq_puts(s, "NBD_FLAG_SEND_TRIM\n"); |
| |
| return 0; |
| } |
| |
| static int nbd_dbg_flags_open(struct inode *inode, struct file *file) |
| { |
| return single_open(file, nbd_dbg_flags_show, inode->i_private); |
| } |
| |
| static const struct file_operations nbd_dbg_flags_ops = { |
| .open = nbd_dbg_flags_open, |
| .read = seq_read, |
| .llseek = seq_lseek, |
| .release = single_release, |
| }; |
| |
| static int nbd_dev_dbg_init(struct nbd_device *nbd) |
| { |
| struct dentry *dir; |
| |
| if (!nbd_dbg_dir) |
| return -EIO; |
| |
| dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir); |
| if (!dir) { |
| dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s'\n", |
| nbd_name(nbd)); |
| return -EIO; |
| } |
| nbd->dbg_dir = dir; |
| |
| debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_ops); |
| debugfs_create_u64("size_bytes", 0444, dir, &nbd->bytesize); |
| debugfs_create_u32("timeout", 0444, dir, &nbd->tag_set.timeout); |
| debugfs_create_u64("blocksize", 0444, dir, &nbd->blksize); |
| debugfs_create_file("flags", 0444, dir, nbd, &nbd_dbg_flags_ops); |
| |
| return 0; |
| } |
| |
| static void nbd_dev_dbg_close(struct nbd_device *nbd) |
| { |
| debugfs_remove_recursive(nbd->dbg_dir); |
| } |
| |
| static int nbd_dbg_init(void) |
| { |
| struct dentry *dbg_dir; |
| |
| dbg_dir = debugfs_create_dir("nbd", NULL); |
| if (!dbg_dir) |
| return -EIO; |
| |
| nbd_dbg_dir = dbg_dir; |
| |
| return 0; |
| } |
| |
| static void nbd_dbg_close(void) |
| { |
| debugfs_remove_recursive(nbd_dbg_dir); |
| } |
| |
| #else /* IS_ENABLED(CONFIG_DEBUG_FS) */ |
| |
| static int nbd_dev_dbg_init(struct nbd_device *nbd) |
| { |
| return 0; |
| } |
| |
| static void nbd_dev_dbg_close(struct nbd_device *nbd) |
| { |
| } |
| |
| static int nbd_dbg_init(void) |
| { |
| return 0; |
| } |
| |
| static void nbd_dbg_close(void) |
| { |
| } |
| |
| #endif |
| |
| static int nbd_init_request(void *data, struct request *rq, |
| unsigned int hctx_idx, unsigned int request_idx, |
| unsigned int numa_node) |
| { |
| struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq); |
| cmd->nbd = data; |
| return 0; |
| } |
| |
| static struct blk_mq_ops nbd_mq_ops = { |
| .queue_rq = nbd_queue_rq, |
| .init_request = nbd_init_request, |
| .timeout = nbd_xmit_timeout, |
| }; |
| |
| /* |
| * And here should be modules and kernel interface |
| * (Just smiley confuses emacs :-) |
| */ |
| |
| static int __init nbd_init(void) |
| { |
| int err = -ENOMEM; |
| int i; |
| int part_shift; |
| |
| BUILD_BUG_ON(sizeof(struct nbd_request) != 28); |
| |
| if (max_part < 0) { |
| printk(KERN_ERR "nbd: max_part must be >= 0\n"); |
| return -EINVAL; |
| } |
| |
| part_shift = 0; |
| if (max_part > 0) { |
| part_shift = fls(max_part); |
| |
| /* |
| * Adjust max_part according to part_shift as it is exported |
| * to user space so that user can know the max number of |
| * partition kernel should be able to manage. |
| * |
| * Note that -1 is required because partition 0 is reserved |
| * for the whole disk. |
| */ |
| max_part = (1UL << part_shift) - 1; |
| } |
| |
| if ((1UL << part_shift) > DISK_MAX_PARTS) |
| return -EINVAL; |
| |
| if (nbds_max > 1UL << (MINORBITS - part_shift)) |
| return -EINVAL; |
| |
| nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL); |
| if (!nbd_dev) |
| return -ENOMEM; |
| |
| for (i = 0; i < nbds_max; i++) { |
| struct gendisk *disk = alloc_disk(1 << part_shift); |
| if (!disk) |
| goto out; |
| nbd_dev[i].disk = disk; |
| |
| nbd_dev[i].tag_set.ops = &nbd_mq_ops; |
| nbd_dev[i].tag_set.nr_hw_queues = 1; |
| nbd_dev[i].tag_set.queue_depth = 128; |
| nbd_dev[i].tag_set.numa_node = NUMA_NO_NODE; |
| nbd_dev[i].tag_set.cmd_size = sizeof(struct nbd_cmd); |
| nbd_dev[i].tag_set.flags = BLK_MQ_F_SHOULD_MERGE | |
| BLK_MQ_F_SG_MERGE | BLK_MQ_F_BLOCKING; |
| nbd_dev[i].tag_set.driver_data = &nbd_dev[i]; |
| |
| err = blk_mq_alloc_tag_set(&nbd_dev[i].tag_set); |
| if (err) { |
| put_disk(disk); |
| goto out; |
| } |
| |
| /* |
| * The new linux 2.5 block layer implementation requires |
| * every gendisk to have its very own request_queue struct. |
| * These structs are big so we dynamically allocate them. |
| */ |
| disk->queue = blk_mq_init_queue(&nbd_dev[i].tag_set); |
| if (!disk->queue) { |
| blk_mq_free_tag_set(&nbd_dev[i].tag_set); |
| put_disk(disk); |
| goto out; |
| } |
| |
| /* |
| * Tell the block layer that we are not a rotational device |
| */ |
| queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue); |
| queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, disk->queue); |
| disk->queue->limits.discard_granularity = 512; |
| blk_queue_max_discard_sectors(disk->queue, UINT_MAX); |
| disk->queue->limits.discard_zeroes_data = 0; |
| blk_queue_max_hw_sectors(disk->queue, 65536); |
| disk->queue->limits.max_sectors = 256; |
| } |
| |
| if (register_blkdev(NBD_MAJOR, "nbd")) { |
| err = -EIO; |
| goto out; |
| } |
| |
| printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR); |
| |
| nbd_dbg_init(); |
| |
| for (i = 0; i < nbds_max; i++) { |
| struct gendisk *disk = nbd_dev[i].disk; |
| nbd_dev[i].magic = NBD_MAGIC; |
| mutex_init(&nbd_dev[i].config_lock); |
| disk->major = NBD_MAJOR; |
| disk->first_minor = i << part_shift; |
| disk->fops = &nbd_fops; |
| disk->private_data = &nbd_dev[i]; |
| sprintf(disk->disk_name, "nbd%d", i); |
| init_waitqueue_head(&nbd_dev[i].recv_wq); |
| nbd_reset(&nbd_dev[i]); |
| add_disk(disk); |
| } |
| |
| return 0; |
| out: |
| while (i--) { |
| blk_mq_free_tag_set(&nbd_dev[i].tag_set); |
| blk_cleanup_queue(nbd_dev[i].disk->queue); |
| put_disk(nbd_dev[i].disk); |
| } |
| kfree(nbd_dev); |
| return err; |
| } |
| |
| static void __exit nbd_cleanup(void) |
| { |
| int i; |
| |
| nbd_dbg_close(); |
| |
| for (i = 0; i < nbds_max; i++) { |
| struct gendisk *disk = nbd_dev[i].disk; |
| nbd_dev[i].magic = 0; |
| if (disk) { |
| del_gendisk(disk); |
| blk_cleanup_queue(disk->queue); |
| blk_mq_free_tag_set(&nbd_dev[i].tag_set); |
| put_disk(disk); |
| } |
| } |
| unregister_blkdev(NBD_MAJOR, "nbd"); |
| kfree(nbd_dev); |
| printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR); |
| } |
| |
| module_init(nbd_init); |
| module_exit(nbd_cleanup); |
| |
| MODULE_DESCRIPTION("Network Block Device"); |
| MODULE_LICENSE("GPL"); |
| |
| module_param(nbds_max, int, 0444); |
| MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)"); |
| module_param(max_part, int, 0444); |
| MODULE_PARM_DESC(max_part, "number of partitions per device (default: 0)"); |