| /* |
| * 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 <asm/uaccess.h> |
| #include <asm/types.h> |
| |
| #include <linux/nbd.h> |
| |
| struct nbd_device { |
| int flags; |
| int harderror; /* Code of hard error */ |
| struct socket * sock; /* If == NULL, device is not ready, yet */ |
| int magic; |
| |
| spinlock_t queue_lock; |
| struct list_head queue_head; /* Requests waiting result */ |
| struct request *active_req; |
| wait_queue_head_t active_wq; |
| struct list_head waiting_queue; /* Requests to be sent */ |
| wait_queue_head_t waiting_wq; |
| |
| struct mutex tx_lock; |
| struct gendisk *disk; |
| int blksize; |
| loff_t bytesize; |
| pid_t pid; /* pid of nbd-client, if attached */ |
| int xmit_timeout; |
| int disconnect; /* a disconnect has been requested by user */ |
| }; |
| |
| #define NBD_MAGIC 0x68797548 |
| |
| static unsigned int nbds_max = 16; |
| static struct nbd_device *nbd_dev; |
| static int max_part; |
| |
| /* |
| * Use just one lock (or at most 1 per NIC). Two arguments for this: |
| * 1. Each NIC is essentially a synchronization point for all servers |
| * accessed through that NIC so there's no need to have more locks |
| * than NICs anyway. |
| * 2. More locks lead to more "Dirty cache line bouncing" which will slow |
| * down each lock to the point where they're actually slower than just |
| * a single lock. |
| * Thanks go to Jens Axboe and Al Viro for their LKML emails explaining this! |
| */ |
| static DEFINE_SPINLOCK(nbd_lock); |
| |
| static inline struct device *nbd_to_dev(struct nbd_device *nbd) |
| { |
| return disk_to_dev(nbd->disk); |
| } |
| |
| 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 void nbd_end_request(struct nbd_device *nbd, struct request *req) |
| { |
| int error = req->errors ? -EIO : 0; |
| struct request_queue *q = req->q; |
| unsigned long flags; |
| |
| dev_dbg(nbd_to_dev(nbd), "request %p: %s\n", req, |
| error ? "failed" : "done"); |
| |
| spin_lock_irqsave(q->queue_lock, flags); |
| __blk_end_request_all(req, error); |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| } |
| |
| /* |
| * Forcibly shutdown the socket causing all listeners to error |
| */ |
| static void sock_shutdown(struct nbd_device *nbd, int lock) |
| { |
| if (lock) |
| mutex_lock(&nbd->tx_lock); |
| if (nbd->sock) { |
| dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n"); |
| kernel_sock_shutdown(nbd->sock, SHUT_RDWR); |
| nbd->sock = NULL; |
| } |
| if (lock) |
| mutex_unlock(&nbd->tx_lock); |
| } |
| |
| static void nbd_xmit_timeout(unsigned long arg) |
| { |
| struct task_struct *task = (struct task_struct *)arg; |
| |
| printk(KERN_WARNING "nbd: killing hung xmit (%s, pid: %d)\n", |
| task->comm, task->pid); |
| force_sig(SIGKILL, task); |
| } |
| |
| /* |
| * Send or receive packet. |
| */ |
| static int sock_xmit(struct nbd_device *nbd, int send, void *buf, int size, |
| int msg_flags) |
| { |
| struct socket *sock = nbd->sock; |
| int result; |
| struct msghdr msg; |
| struct kvec iov; |
| sigset_t blocked, oldset; |
| unsigned long pflags = current->flags; |
| |
| if (unlikely(!sock)) { |
| dev_err(disk_to_dev(nbd->disk), |
| "Attempted %s on closed socket in sock_xmit\n", |
| (send ? "send" : "recv")); |
| return -EINVAL; |
| } |
| |
| /* Allow interception of SIGKILL only |
| * Don't allow other signals to interrupt the transmission */ |
| siginitsetinv(&blocked, sigmask(SIGKILL)); |
| sigprocmask(SIG_SETMASK, &blocked, &oldset); |
| |
| 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) { |
| struct timer_list ti; |
| |
| if (nbd->xmit_timeout) { |
| init_timer(&ti); |
| ti.function = nbd_xmit_timeout; |
| ti.data = (unsigned long)current; |
| ti.expires = jiffies + nbd->xmit_timeout; |
| add_timer(&ti); |
| } |
| result = kernel_sendmsg(sock, &msg, &iov, 1, size); |
| if (nbd->xmit_timeout) |
| del_timer_sync(&ti); |
| } else |
| result = kernel_recvmsg(sock, &msg, &iov, 1, size, |
| msg.msg_flags); |
| |
| if (signal_pending(current)) { |
| siginfo_t info; |
| printk(KERN_WARNING "nbd (pid %d: %s) got signal %d\n", |
| task_pid_nr(current), current->comm, |
| dequeue_signal_lock(current, ¤t->blocked, &info)); |
| result = -EINTR; |
| sock_shutdown(nbd, !send); |
| break; |
| } |
| |
| if (result <= 0) { |
| if (result == 0) |
| result = -EPIPE; /* short read */ |
| break; |
| } |
| size -= result; |
| buf += result; |
| } while (size > 0); |
| |
| sigprocmask(SIG_SETMASK, &oldset, NULL); |
| tsk_restore_flags(current, pflags, PF_MEMALLOC); |
| |
| return result; |
| } |
| |
| static inline int sock_send_bvec(struct nbd_device *nbd, struct bio_vec *bvec, |
| int flags) |
| { |
| int result; |
| void *kaddr = kmap(bvec->bv_page); |
| result = sock_xmit(nbd, 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_req(struct nbd_device *nbd, struct request *req) |
| { |
| int result, flags; |
| struct nbd_request request; |
| unsigned long size = blk_rq_bytes(req); |
| u32 type; |
| |
| if (req->cmd_type == REQ_TYPE_DRV_PRIV) |
| type = NBD_CMD_DISC; |
| else if (req->cmd_flags & REQ_DISCARD) |
| type = NBD_CMD_TRIM; |
| else if (req->cmd_flags & REQ_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 && type != NBD_CMD_DISC) { |
| request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9); |
| request.len = htonl(size); |
| } |
| memcpy(request.handle, &req, sizeof(req)); |
| |
| dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n", |
| req, nbdcmd_to_ascii(type), |
| (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req)); |
| result = sock_xmit(nbd, 1, &request, sizeof(request), |
| (type == NBD_CMD_WRITE) ? MSG_MORE : 0); |
| if (result <= 0) { |
| dev_err(disk_to_dev(nbd->disk), |
| "Send control failed (result %d)\n", result); |
| return -EIO; |
| } |
| |
| if (type == NBD_CMD_WRITE) { |
| struct req_iterator iter; |
| struct bio_vec bvec; |
| /* |
| * we are really probing at internals to determine |
| * whether to set MSG_MORE or not... |
| */ |
| rq_for_each_segment(bvec, req, iter) { |
| flags = 0; |
| if (!rq_iter_last(bvec, iter)) |
| flags = MSG_MORE; |
| dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n", |
| req, bvec.bv_len); |
| result = sock_send_bvec(nbd, &bvec, flags); |
| if (result <= 0) { |
| dev_err(disk_to_dev(nbd->disk), |
| "Send data failed (result %d)\n", |
| result); |
| return -EIO; |
| } |
| } |
| } |
| return 0; |
| } |
| |
| static struct request *nbd_find_request(struct nbd_device *nbd, |
| struct request *xreq) |
| { |
| struct request *req, *tmp; |
| int err; |
| |
| err = wait_event_interruptible(nbd->active_wq, nbd->active_req != xreq); |
| if (unlikely(err)) |
| return ERR_PTR(err); |
| |
| spin_lock(&nbd->queue_lock); |
| list_for_each_entry_safe(req, tmp, &nbd->queue_head, queuelist) { |
| if (req != xreq) |
| continue; |
| list_del_init(&req->queuelist); |
| spin_unlock(&nbd->queue_lock); |
| return req; |
| } |
| spin_unlock(&nbd->queue_lock); |
| |
| return ERR_PTR(-ENOENT); |
| } |
| |
| static inline int sock_recv_bvec(struct nbd_device *nbd, struct bio_vec *bvec) |
| { |
| int result; |
| void *kaddr = kmap(bvec->bv_page); |
| result = sock_xmit(nbd, 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 request *nbd_read_stat(struct nbd_device *nbd) |
| { |
| int result; |
| struct nbd_reply reply; |
| struct request *req; |
| |
| reply.magic = 0; |
| result = sock_xmit(nbd, 0, &reply, sizeof(reply), MSG_WAITALL); |
| if (result <= 0) { |
| dev_err(disk_to_dev(nbd->disk), |
| "Receive control failed (result %d)\n", result); |
| goto harderror; |
| } |
| |
| if (ntohl(reply.magic) != NBD_REPLY_MAGIC) { |
| dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n", |
| (unsigned long)ntohl(reply.magic)); |
| result = -EPROTO; |
| goto harderror; |
| } |
| |
| req = nbd_find_request(nbd, *(struct request **)reply.handle); |
| if (IS_ERR(req)) { |
| result = PTR_ERR(req); |
| if (result != -ENOENT) |
| goto harderror; |
| |
| dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%p)\n", |
| reply.handle); |
| result = -EBADR; |
| goto harderror; |
| } |
| |
| if (ntohl(reply.error)) { |
| dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n", |
| ntohl(reply.error)); |
| req->errors++; |
| return req; |
| } |
| |
| dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", req); |
| 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, &bvec); |
| if (result <= 0) { |
| dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n", |
| result); |
| req->errors++; |
| return req; |
| } |
| dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n", |
| req, bvec.bv_len); |
| } |
| } |
| return req; |
| harderror: |
| nbd->harderror = result; |
| return NULL; |
| } |
| |
| static ssize_t pid_show(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| struct gendisk *disk = dev_to_disk(dev); |
| |
| return sprintf(buf, "%ld\n", |
| (long) ((struct nbd_device *)disk->private_data)->pid); |
| } |
| |
| static struct device_attribute pid_attr = { |
| .attr = { .name = "pid", .mode = S_IRUGO}, |
| .show = pid_show, |
| }; |
| |
| static int nbd_do_it(struct nbd_device *nbd) |
| { |
| struct request *req; |
| int ret; |
| |
| BUG_ON(nbd->magic != NBD_MAGIC); |
| |
| sk_set_memalloc(nbd->sock->sk); |
| nbd->pid = task_pid_nr(current); |
| ret = device_create_file(disk_to_dev(nbd->disk), &pid_attr); |
| if (ret) { |
| dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n"); |
| nbd->pid = 0; |
| return ret; |
| } |
| |
| while ((req = nbd_read_stat(nbd)) != NULL) |
| nbd_end_request(nbd, req); |
| |
| device_remove_file(disk_to_dev(nbd->disk), &pid_attr); |
| nbd->pid = 0; |
| return 0; |
| } |
| |
| static void nbd_clear_que(struct nbd_device *nbd) |
| { |
| struct request *req; |
| |
| BUG_ON(nbd->magic != NBD_MAGIC); |
| |
| /* |
| * Because we have set nbd->sock to NULL under the tx_lock, all |
| * modifications to the list must have completed by now. For |
| * the same reason, the active_req must be NULL. |
| * |
| * As a consequence, we don't need to take the spin lock while |
| * purging the list here. |
| */ |
| BUG_ON(nbd->sock); |
| BUG_ON(nbd->active_req); |
| |
| while (!list_empty(&nbd->queue_head)) { |
| req = list_entry(nbd->queue_head.next, struct request, |
| queuelist); |
| list_del_init(&req->queuelist); |
| req->errors++; |
| nbd_end_request(nbd, req); |
| } |
| |
| while (!list_empty(&nbd->waiting_queue)) { |
| req = list_entry(nbd->waiting_queue.next, struct request, |
| queuelist); |
| list_del_init(&req->queuelist); |
| req->errors++; |
| nbd_end_request(nbd, req); |
| } |
| } |
| |
| |
| static void nbd_handle_req(struct nbd_device *nbd, struct request *req) |
| { |
| if (req->cmd_type != REQ_TYPE_FS) |
| goto error_out; |
| |
| if (rq_data_dir(req) == WRITE && |
| (nbd->flags & NBD_FLAG_READ_ONLY)) { |
| dev_err(disk_to_dev(nbd->disk), |
| "Write on read-only\n"); |
| goto error_out; |
| } |
| |
| req->errors = 0; |
| |
| mutex_lock(&nbd->tx_lock); |
| if (unlikely(!nbd->sock)) { |
| mutex_unlock(&nbd->tx_lock); |
| dev_err(disk_to_dev(nbd->disk), |
| "Attempted send on closed socket\n"); |
| goto error_out; |
| } |
| |
| nbd->active_req = req; |
| |
| if (nbd_send_req(nbd, req) != 0) { |
| dev_err(disk_to_dev(nbd->disk), "Request send failed\n"); |
| req->errors++; |
| nbd_end_request(nbd, req); |
| } else { |
| spin_lock(&nbd->queue_lock); |
| list_add_tail(&req->queuelist, &nbd->queue_head); |
| spin_unlock(&nbd->queue_lock); |
| } |
| |
| nbd->active_req = NULL; |
| mutex_unlock(&nbd->tx_lock); |
| wake_up_all(&nbd->active_wq); |
| |
| return; |
| |
| error_out: |
| req->errors++; |
| nbd_end_request(nbd, req); |
| } |
| |
| static int nbd_thread(void *data) |
| { |
| struct nbd_device *nbd = data; |
| struct request *req; |
| |
| set_user_nice(current, MIN_NICE); |
| while (!kthread_should_stop() || !list_empty(&nbd->waiting_queue)) { |
| /* wait for something to do */ |
| wait_event_interruptible(nbd->waiting_wq, |
| kthread_should_stop() || |
| !list_empty(&nbd->waiting_queue)); |
| |
| /* extract request */ |
| if (list_empty(&nbd->waiting_queue)) |
| continue; |
| |
| spin_lock_irq(&nbd->queue_lock); |
| req = list_entry(nbd->waiting_queue.next, struct request, |
| queuelist); |
| list_del_init(&req->queuelist); |
| spin_unlock_irq(&nbd->queue_lock); |
| |
| /* handle request */ |
| nbd_handle_req(nbd, req); |
| } |
| return 0; |
| } |
| |
| /* |
| * We always wait for result of write, for now. It would be nice to make it optional |
| * in future |
| * if ((rq_data_dir(req) == WRITE) && (nbd->flags & NBD_WRITE_NOCHK)) |
| * { printk( "Warning: Ignoring result!\n"); nbd_end_request( req ); } |
| */ |
| |
| static void do_nbd_request(struct request_queue *q) |
| __releases(q->queue_lock) __acquires(q->queue_lock) |
| { |
| struct request *req; |
| |
| while ((req = blk_fetch_request(q)) != NULL) { |
| struct nbd_device *nbd; |
| |
| spin_unlock_irq(q->queue_lock); |
| |
| nbd = req->rq_disk->private_data; |
| |
| BUG_ON(nbd->magic != NBD_MAGIC); |
| |
| dev_dbg(nbd_to_dev(nbd), "request %p: dequeued (flags=%x)\n", |
| req, req->cmd_type); |
| |
| if (unlikely(!nbd->sock)) { |
| dev_err(disk_to_dev(nbd->disk), |
| "Attempted send on closed socket\n"); |
| req->errors++; |
| nbd_end_request(nbd, req); |
| spin_lock_irq(q->queue_lock); |
| continue; |
| } |
| |
| spin_lock_irq(&nbd->queue_lock); |
| list_add_tail(&req->queuelist, &nbd->waiting_queue); |
| spin_unlock_irq(&nbd->queue_lock); |
| |
| wake_up(&nbd->waiting_wq); |
| |
| spin_lock_irq(q->queue_lock); |
| } |
| } |
| |
| /* Must be called with tx_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: { |
| struct request sreq; |
| |
| dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n"); |
| if (!nbd->sock) |
| return -EINVAL; |
| |
| mutex_unlock(&nbd->tx_lock); |
| fsync_bdev(bdev); |
| mutex_lock(&nbd->tx_lock); |
| blk_rq_init(NULL, &sreq); |
| sreq.cmd_type = REQ_TYPE_DRV_PRIV; |
| |
| /* Check again after getting mutex back. */ |
| if (!nbd->sock) |
| return -EINVAL; |
| |
| nbd->disconnect = 1; |
| |
| nbd_send_req(nbd, &sreq); |
| return 0; |
| } |
| |
| case NBD_CLEAR_SOCK: { |
| struct socket *sock = nbd->sock; |
| nbd->sock = NULL; |
| nbd_clear_que(nbd); |
| BUG_ON(!list_empty(&nbd->queue_head)); |
| BUG_ON(!list_empty(&nbd->waiting_queue)); |
| kill_bdev(bdev); |
| if (sock) |
| sockfd_put(sock); |
| return 0; |
| } |
| |
| case NBD_SET_SOCK: { |
| struct socket *sock; |
| int err; |
| if (nbd->sock) |
| return -EBUSY; |
| sock = sockfd_lookup(arg, &err); |
| if (sock) { |
| nbd->sock = sock; |
| if (max_part > 0) |
| bdev->bd_invalidated = 1; |
| nbd->disconnect = 0; /* we're connected now */ |
| return 0; |
| } |
| return -EINVAL; |
| } |
| |
| case NBD_SET_BLKSIZE: |
| nbd->blksize = arg; |
| nbd->bytesize &= ~(nbd->blksize-1); |
| bdev->bd_inode->i_size = nbd->bytesize; |
| set_blocksize(bdev, nbd->blksize); |
| set_capacity(nbd->disk, nbd->bytesize >> 9); |
| return 0; |
| |
| case NBD_SET_SIZE: |
| nbd->bytesize = arg & ~(nbd->blksize-1); |
| bdev->bd_inode->i_size = nbd->bytesize; |
| set_blocksize(bdev, nbd->blksize); |
| set_capacity(nbd->disk, nbd->bytesize >> 9); |
| return 0; |
| |
| case NBD_SET_TIMEOUT: |
| nbd->xmit_timeout = arg * HZ; |
| return 0; |
| |
| case NBD_SET_FLAGS: |
| nbd->flags = arg; |
| return 0; |
| |
| case NBD_SET_SIZE_BLOCKS: |
| nbd->bytesize = ((u64) arg) * nbd->blksize; |
| bdev->bd_inode->i_size = nbd->bytesize; |
| set_blocksize(bdev, nbd->blksize); |
| set_capacity(nbd->disk, nbd->bytesize >> 9); |
| return 0; |
| |
| case NBD_DO_IT: { |
| struct task_struct *thread; |
| struct socket *sock; |
| int error; |
| |
| if (nbd->pid) |
| return -EBUSY; |
| if (!nbd->sock) |
| return -EINVAL; |
| |
| mutex_unlock(&nbd->tx_lock); |
| |
| 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_flush(nbd->disk->queue, REQ_FLUSH); |
| else |
| blk_queue_flush(nbd->disk->queue, 0); |
| |
| thread = kthread_run(nbd_thread, nbd, "%s", |
| nbd->disk->disk_name); |
| if (IS_ERR(thread)) { |
| mutex_lock(&nbd->tx_lock); |
| return PTR_ERR(thread); |
| } |
| |
| error = nbd_do_it(nbd); |
| kthread_stop(thread); |
| |
| mutex_lock(&nbd->tx_lock); |
| if (error) |
| return error; |
| sock_shutdown(nbd, 0); |
| sock = nbd->sock; |
| nbd->sock = NULL; |
| nbd_clear_que(nbd); |
| dev_warn(disk_to_dev(nbd->disk), "queue cleared\n"); |
| kill_bdev(bdev); |
| queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue); |
| set_device_ro(bdev, false); |
| if (sock) |
| sockfd_put(sock); |
| nbd->flags = 0; |
| nbd->bytesize = 0; |
| bdev->bd_inode->i_size = 0; |
| set_capacity(nbd->disk, 0); |
| if (max_part > 0) |
| blkdev_reread_part(bdev); |
| if (nbd->disconnect) /* user requested, ignore socket errors */ |
| return 0; |
| return nbd->harderror; |
| } |
| |
| 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: |
| dev_info(disk_to_dev(nbd->disk), |
| "next = %p, prev = %p, head = %p\n", |
| nbd->queue_head.next, nbd->queue_head.prev, |
| &nbd->queue_head); |
| 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->tx_lock); |
| error = __nbd_ioctl(bdev, nbd, cmd, arg); |
| mutex_unlock(&nbd->tx_lock); |
| |
| return error; |
| } |
| |
| static const struct block_device_operations nbd_fops = |
| { |
| .owner = THIS_MODULE, |
| .ioctl = nbd_ioctl, |
| }; |
| |
| /* |
| * 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; |
| /* |
| * 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_init_queue(do_nbd_request, &nbd_lock); |
| if (!disk->queue) { |
| 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); |
| |
| for (i = 0; i < nbds_max; i++) { |
| struct gendisk *disk = nbd_dev[i].disk; |
| nbd_dev[i].magic = NBD_MAGIC; |
| INIT_LIST_HEAD(&nbd_dev[i].waiting_queue); |
| spin_lock_init(&nbd_dev[i].queue_lock); |
| INIT_LIST_HEAD(&nbd_dev[i].queue_head); |
| mutex_init(&nbd_dev[i].tx_lock); |
| init_waitqueue_head(&nbd_dev[i].active_wq); |
| init_waitqueue_head(&nbd_dev[i].waiting_wq); |
| nbd_dev[i].blksize = 1024; |
| nbd_dev[i].bytesize = 0; |
| 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); |
| set_capacity(disk, 0); |
| add_disk(disk); |
| } |
| |
| return 0; |
| out: |
| while (i--) { |
| 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; |
| 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); |
| 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)"); |