From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- drivers/block/nbd.c | 731 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 731 insertions(+) create mode 100644 drivers/block/nbd.c (limited to 'drivers/block/nbd.c') diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c new file mode 100644 index 000000000000..efdf04450bf7 --- /dev/null +++ b/drivers/block/nbd.c @@ -0,0 +1,731 @@ +/* + * 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 Pavel Machek + * Parts copyright 2001 Steven Whitehouse + * + * (part of code stolen from loop.c) + * + * 97-3-25 compiled 0-th version, not yet tested it + * (it did not work, BTW) (later that day) HEY! it works! + * (bit later) hmm, not that much... 2:00am next day: + * yes, it works, but it gives something like 50kB/sec + * 97-4-01 complete rewrite to make it possible for many requests at + * once to be processed + * 97-4-11 Making protocol independent of endianity etc. + * 97-9-13 Cosmetic changes + * 98-5-13 Attempt to make 64-bit-clean on 64-bit machines + * 99-1-11 Attempt to make 64-bit-clean on 32-bit machines + * 01-2-27 Fix to store proper blockcount for kernel (calculated using + * BLOCK_SIZE_BITS, not device blocksize) + * 01-3-11 Make nbd work with new Linux block layer code. It now supports + * plugging like all the other block devices. Also added in MSG_MORE to + * reduce number of partial TCP segments sent. + * 01-12-6 Fix deadlock condition by making queue locks independent of + * the transmit lock. + * 02-10-11 Allow hung xmit to be aborted via SIGKILL & various fixes. + * + * 03-06-22 Make nbd work with new linux 2.5 block layer design. This fixes + * memory corruption from module removal and possible memory corruption + * from sending/receiving disk data. + * 03-06-23 Cosmetic changes. + * 03-06-23 Enhance diagnostics support. + * 03-06-24 Remove unneeded blksize_bits field from nbd_device struct. + * + * 03-06-24 Cleanup PARANOIA usage & code. + * 04-02-19 Remove PARANOIA, plus various cleanups (Paul Clements) + * possible FIXME: make set_sock / set_blksize / set_size / do_it one syscall + * why not: would need access_ok and friends, would share yet another + * structure with userland + */ + +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include +#include + +#include + +#define LO_MAGIC 0x68797548 + +#ifdef NDEBUG +#define dprintk(flags, fmt...) +#else /* NDEBUG */ +#define dprintk(flags, fmt...) do { \ + if (debugflags & (flags)) printk(KERN_DEBUG fmt); \ +} while (0) +#define DBG_IOCTL 0x0004 +#define DBG_INIT 0x0010 +#define DBG_EXIT 0x0020 +#define DBG_BLKDEV 0x0100 +#define DBG_RX 0x0200 +#define DBG_TX 0x0400 +static unsigned int debugflags; +#endif /* NDEBUG */ + +static struct nbd_device nbd_dev[MAX_NBD]; + +/* + * 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); + +#ifndef NDEBUG +static const char *ioctl_cmd_to_ascii(int cmd) +{ + switch (cmd) { + case NBD_SET_SOCK: return "set-sock"; + case NBD_SET_BLKSIZE: return "set-blksize"; + case NBD_SET_SIZE: return "set-size"; + case NBD_DO_IT: return "do-it"; + case NBD_CLEAR_SOCK: return "clear-sock"; + case NBD_CLEAR_QUE: return "clear-que"; + case NBD_PRINT_DEBUG: return "print-debug"; + case NBD_SET_SIZE_BLOCKS: return "set-size-blocks"; + case NBD_DISCONNECT: return "disconnect"; + case BLKROSET: return "set-read-only"; + case BLKFLSBUF: return "flush-buffer-cache"; + } + return "unknown"; +} + +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"; + } + return "invalid"; +} +#endif /* NDEBUG */ + +static void nbd_end_request(struct request *req) +{ + int uptodate = (req->errors == 0) ? 1 : 0; + request_queue_t *q = req->q; + unsigned long flags; + + dprintk(DBG_BLKDEV, "%s: request %p: %s\n", req->rq_disk->disk_name, + req, uptodate? "done": "failed"); + + spin_lock_irqsave(q->queue_lock, flags); + if (!end_that_request_first(req, uptodate, req->nr_sectors)) { + end_that_request_last(req); + } + spin_unlock_irqrestore(q->queue_lock, flags); +} + +/* + * Send or receive packet. + */ +static int sock_xmit(struct socket *sock, int send, void *buf, int size, + int msg_flags) +{ + int result; + struct msghdr msg; + struct kvec iov; + unsigned long flags; + sigset_t oldset; + + /* Allow interception of SIGKILL only + * Don't allow other signals to interrupt the transmission */ + spin_lock_irqsave(¤t->sighand->siglock, flags); + oldset = current->blocked; + sigfillset(¤t->blocked); + sigdelsetmask(¤t->blocked, sigmask(SIGKILL)); + recalc_sigpending(); + spin_unlock_irqrestore(¤t->sighand->siglock, flags); + + do { + sock->sk->sk_allocation = GFP_NOIO; + 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_namelen = 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, 0); + + if (signal_pending(current)) { + siginfo_t info; + spin_lock_irqsave(¤t->sighand->siglock, flags); + printk(KERN_WARNING "nbd (pid %d: %s) got signal %d\n", + current->pid, current->comm, + dequeue_signal(current, ¤t->blocked, &info)); + spin_unlock_irqrestore(¤t->sighand->siglock, flags); + result = -EINTR; + break; + } + + if (result <= 0) { + if (result == 0) + result = -EPIPE; /* short read */ + break; + } + size -= result; + buf += result; + } while (size > 0); + + spin_lock_irqsave(¤t->sighand->siglock, flags); + current->blocked = oldset; + recalc_sigpending(); + spin_unlock_irqrestore(¤t->sighand->siglock, flags); + + return result; +} + +static inline int sock_send_bvec(struct socket *sock, struct bio_vec *bvec, + int flags) +{ + int result; + void *kaddr = kmap(bvec->bv_page); + result = sock_xmit(sock, 1, kaddr + bvec->bv_offset, bvec->bv_len, + flags); + kunmap(bvec->bv_page); + return result; +} + +static int nbd_send_req(struct nbd_device *lo, struct request *req) +{ + int result, i, flags; + struct nbd_request request; + unsigned long size = req->nr_sectors << 9; + struct socket *sock = lo->sock; + + request.magic = htonl(NBD_REQUEST_MAGIC); + request.type = htonl(nbd_cmd(req)); + request.from = cpu_to_be64((u64) req->sector << 9); + request.len = htonl(size); + memcpy(request.handle, &req, sizeof(req)); + + down(&lo->tx_lock); + + if (!sock || !lo->sock) { + printk(KERN_ERR "%s: Attempted send on closed socket\n", + lo->disk->disk_name); + goto error_out; + } + + dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%luB)\n", + lo->disk->disk_name, req, + nbdcmd_to_ascii(nbd_cmd(req)), + (unsigned long long)req->sector << 9, + req->nr_sectors << 9); + result = sock_xmit(sock, 1, &request, sizeof(request), + (nbd_cmd(req) == NBD_CMD_WRITE)? MSG_MORE: 0); + if (result <= 0) { + printk(KERN_ERR "%s: Send control failed (result %d)\n", + lo->disk->disk_name, result); + goto error_out; + } + + if (nbd_cmd(req) == NBD_CMD_WRITE) { + struct bio *bio; + /* + * we are really probing at internals to determine + * whether to set MSG_MORE or not... + */ + rq_for_each_bio(bio, req) { + struct bio_vec *bvec; + bio_for_each_segment(bvec, bio, i) { + flags = 0; + if ((i < (bio->bi_vcnt - 1)) || bio->bi_next) + flags = MSG_MORE; + dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n", + lo->disk->disk_name, req, + bvec->bv_len); + result = sock_send_bvec(sock, bvec, flags); + if (result <= 0) { + printk(KERN_ERR "%s: Send data failed (result %d)\n", + lo->disk->disk_name, + result); + goto error_out; + } + } + } + } + up(&lo->tx_lock); + return 0; + +error_out: + up(&lo->tx_lock); + return 1; +} + +static struct request *nbd_find_request(struct nbd_device *lo, char *handle) +{ + struct request *req; + struct list_head *tmp; + struct request *xreq; + + memcpy(&xreq, handle, sizeof(xreq)); + + spin_lock(&lo->queue_lock); + list_for_each(tmp, &lo->queue_head) { + req = list_entry(tmp, struct request, queuelist); + if (req != xreq) + continue; + list_del_init(&req->queuelist); + spin_unlock(&lo->queue_lock); + return req; + } + spin_unlock(&lo->queue_lock); + return NULL; +} + +static inline int sock_recv_bvec(struct socket *sock, struct bio_vec *bvec) +{ + int result; + void *kaddr = kmap(bvec->bv_page); + result = sock_xmit(sock, 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 *lo) +{ + int result; + struct nbd_reply reply; + struct request *req; + struct socket *sock = lo->sock; + + reply.magic = 0; + result = sock_xmit(sock, 0, &reply, sizeof(reply), MSG_WAITALL); + if (result <= 0) { + printk(KERN_ERR "%s: Receive control failed (result %d)\n", + lo->disk->disk_name, result); + goto harderror; + } + req = nbd_find_request(lo, reply.handle); + if (req == NULL) { + printk(KERN_ERR "%s: Unexpected reply (%p)\n", + lo->disk->disk_name, reply.handle); + result = -EBADR; + goto harderror; + } + + if (ntohl(reply.magic) != NBD_REPLY_MAGIC) { + printk(KERN_ERR "%s: Wrong magic (0x%lx)\n", + lo->disk->disk_name, + (unsigned long)ntohl(reply.magic)); + result = -EPROTO; + goto harderror; + } + if (ntohl(reply.error)) { + printk(KERN_ERR "%s: Other side returned error (%d)\n", + lo->disk->disk_name, ntohl(reply.error)); + req->errors++; + return req; + } + + dprintk(DBG_RX, "%s: request %p: got reply\n", + lo->disk->disk_name, req); + if (nbd_cmd(req) == NBD_CMD_READ) { + int i; + struct bio *bio; + rq_for_each_bio(bio, req) { + struct bio_vec *bvec; + bio_for_each_segment(bvec, bio, i) { + result = sock_recv_bvec(sock, bvec); + if (result <= 0) { + printk(KERN_ERR "%s: Receive data failed (result %d)\n", + lo->disk->disk_name, + result); + goto harderror; + } + dprintk(DBG_RX, "%s: request %p: got %d bytes data\n", + lo->disk->disk_name, req, bvec->bv_len); + } + } + } + return req; +harderror: + lo->harderror = result; + return NULL; +} + +static void nbd_do_it(struct nbd_device *lo) +{ + struct request *req; + + BUG_ON(lo->magic != LO_MAGIC); + + while ((req = nbd_read_stat(lo)) != NULL) + nbd_end_request(req); + return; +} + +static void nbd_clear_que(struct nbd_device *lo) +{ + struct request *req; + + BUG_ON(lo->magic != LO_MAGIC); + + do { + req = NULL; + spin_lock(&lo->queue_lock); + if (!list_empty(&lo->queue_head)) { + req = list_entry(lo->queue_head.next, struct request, queuelist); + list_del_init(&req->queuelist); + } + spin_unlock(&lo->queue_lock); + if (req) { + req->errors++; + nbd_end_request(req); + } + } while (req); +} + +/* + * We always wait for result of write, for now. It would be nice to make it optional + * in future + * if ((req->cmd == WRITE) && (lo->flags & NBD_WRITE_NOCHK)) + * { printk( "Warning: Ignoring result!\n"); nbd_end_request( req ); } + */ + +static void do_nbd_request(request_queue_t * q) +{ + struct request *req; + + while ((req = elv_next_request(q)) != NULL) { + struct nbd_device *lo; + + blkdev_dequeue_request(req); + dprintk(DBG_BLKDEV, "%s: request %p: dequeued (flags=%lx)\n", + req->rq_disk->disk_name, req, req->flags); + + if (!(req->flags & REQ_CMD)) + goto error_out; + + lo = req->rq_disk->private_data; + + BUG_ON(lo->magic != LO_MAGIC); + + if (!lo->file) { + printk(KERN_ERR "%s: Request when not-ready\n", + lo->disk->disk_name); + goto error_out; + } + nbd_cmd(req) = NBD_CMD_READ; + if (rq_data_dir(req) == WRITE) { + nbd_cmd(req) = NBD_CMD_WRITE; + if (lo->flags & NBD_READ_ONLY) { + printk(KERN_ERR "%s: Write on read-only\n", + lo->disk->disk_name); + goto error_out; + } + } + + req->errors = 0; + spin_unlock_irq(q->queue_lock); + + spin_lock(&lo->queue_lock); + + if (!lo->file) { + spin_unlock(&lo->queue_lock); + printk(KERN_ERR "%s: failed between accept and semaphore, file lost\n", + lo->disk->disk_name); + req->errors++; + nbd_end_request(req); + spin_lock_irq(q->queue_lock); + continue; + } + + list_add(&req->queuelist, &lo->queue_head); + spin_unlock(&lo->queue_lock); + + if (nbd_send_req(lo, req) != 0) { + printk(KERN_ERR "%s: Request send failed\n", + lo->disk->disk_name); + if (nbd_find_request(lo, (char *)&req) != NULL) { + /* we still own req */ + req->errors++; + nbd_end_request(req); + } else /* we're racing with nbd_clear_que */ + printk(KERN_DEBUG "nbd: can't find req\n"); + } + + spin_lock_irq(q->queue_lock); + continue; + +error_out: + req->errors++; + spin_unlock(q->queue_lock); + nbd_end_request(req); + spin_lock(q->queue_lock); + } + return; +} + +static int nbd_ioctl(struct inode *inode, struct file *file, + unsigned int cmd, unsigned long arg) +{ + struct nbd_device *lo = inode->i_bdev->bd_disk->private_data; + int error; + struct request sreq ; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + BUG_ON(lo->magic != LO_MAGIC); + + /* Anyone capable of this syscall can do *real bad* things */ + dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n", + lo->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg); + + switch (cmd) { + case NBD_DISCONNECT: + printk(KERN_INFO "%s: NBD_DISCONNECT\n", lo->disk->disk_name); + sreq.flags = REQ_SPECIAL; + nbd_cmd(&sreq) = NBD_CMD_DISC; + /* + * Set these to sane values in case server implementation + * fails to check the request type first and also to keep + * debugging output cleaner. + */ + sreq.sector = 0; + sreq.nr_sectors = 0; + if (!lo->sock) + return -EINVAL; + nbd_send_req(lo, &sreq); + return 0; + + case NBD_CLEAR_SOCK: + error = 0; + down(&lo->tx_lock); + lo->sock = NULL; + up(&lo->tx_lock); + spin_lock(&lo->queue_lock); + file = lo->file; + lo->file = NULL; + spin_unlock(&lo->queue_lock); + nbd_clear_que(lo); + spin_lock(&lo->queue_lock); + if (!list_empty(&lo->queue_head)) { + printk(KERN_ERR "nbd: disconnect: some requests are in progress -> please try again.\n"); + error = -EBUSY; + } + spin_unlock(&lo->queue_lock); + if (file) + fput(file); + return error; + case NBD_SET_SOCK: + if (lo->file) + return -EBUSY; + error = -EINVAL; + file = fget(arg); + if (file) { + inode = file->f_dentry->d_inode; + if (S_ISSOCK(inode->i_mode)) { + lo->file = file; + lo->sock = SOCKET_I(inode); + error = 0; + } else { + fput(file); + } + } + return error; + case NBD_SET_BLKSIZE: + lo->blksize = arg; + lo->bytesize &= ~(lo->blksize-1); + inode->i_bdev->bd_inode->i_size = lo->bytesize; + set_blocksize(inode->i_bdev, lo->blksize); + set_capacity(lo->disk, lo->bytesize >> 9); + return 0; + case NBD_SET_SIZE: + lo->bytesize = arg & ~(lo->blksize-1); + inode->i_bdev->bd_inode->i_size = lo->bytesize; + set_blocksize(inode->i_bdev, lo->blksize); + set_capacity(lo->disk, lo->bytesize >> 9); + return 0; + case NBD_SET_SIZE_BLOCKS: + lo->bytesize = ((u64) arg) * lo->blksize; + inode->i_bdev->bd_inode->i_size = lo->bytesize; + set_blocksize(inode->i_bdev, lo->blksize); + set_capacity(lo->disk, lo->bytesize >> 9); + return 0; + case NBD_DO_IT: + if (!lo->file) + return -EINVAL; + nbd_do_it(lo); + /* on return tidy up in case we have a signal */ + /* Forcibly shutdown the socket causing all listeners + * to error + * + * FIXME: This code is duplicated from sys_shutdown, but + * there should be a more generic interface rather than + * calling socket ops directly here */ + down(&lo->tx_lock); + if (lo->sock) { + printk(KERN_WARNING "%s: shutting down socket\n", + lo->disk->disk_name); + lo->sock->ops->shutdown(lo->sock, + SEND_SHUTDOWN|RCV_SHUTDOWN); + lo->sock = NULL; + } + up(&lo->tx_lock); + spin_lock(&lo->queue_lock); + file = lo->file; + lo->file = NULL; + spin_unlock(&lo->queue_lock); + nbd_clear_que(lo); + printk(KERN_WARNING "%s: queue cleared\n", lo->disk->disk_name); + if (file) + fput(file); + return lo->harderror; + case NBD_CLEAR_QUE: + down(&lo->tx_lock); + if (lo->sock) { + up(&lo->tx_lock); + return 0; /* probably should be error, but that would + * break "nbd-client -d", so just return 0 */ + } + up(&lo->tx_lock); + nbd_clear_que(lo); + return 0; + case NBD_PRINT_DEBUG: + printk(KERN_INFO "%s: next = %p, prev = %p, head = %p\n", + inode->i_bdev->bd_disk->disk_name, + lo->queue_head.next, lo->queue_head.prev, + &lo->queue_head); + return 0; + } + return -EINVAL; +} + +static 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; + + if (sizeof(struct nbd_request) != 28) { + printk(KERN_CRIT "nbd: sizeof nbd_request needs to be 28 in order to work!\n" ); + return -EIO; + } + + for (i = 0; i < MAX_NBD; i++) { + struct gendisk *disk = alloc_disk(1); + 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; + } + } + + if (register_blkdev(NBD_MAJOR, "nbd")) { + err = -EIO; + goto out; + } + + printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR); + dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags); + + devfs_mk_dir("nbd"); + for (i = 0; i < MAX_NBD; i++) { + struct gendisk *disk = nbd_dev[i].disk; + nbd_dev[i].file = NULL; + nbd_dev[i].magic = LO_MAGIC; + nbd_dev[i].flags = 0; + spin_lock_init(&nbd_dev[i].queue_lock); + INIT_LIST_HEAD(&nbd_dev[i].queue_head); + init_MUTEX(&nbd_dev[i].tx_lock); + nbd_dev[i].blksize = 1024; + nbd_dev[i].bytesize = 0x7ffffc00ULL << 10; /* 2TB */ + disk->major = NBD_MAJOR; + disk->first_minor = i; + disk->fops = &nbd_fops; + disk->private_data = &nbd_dev[i]; + disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO; + sprintf(disk->disk_name, "nbd%d", i); + sprintf(disk->devfs_name, "nbd/%d", i); + set_capacity(disk, 0x7ffffc00ULL << 1); /* 2 TB */ + add_disk(disk); + } + + return 0; +out: + while (i--) { + blk_cleanup_queue(nbd_dev[i].disk->queue); + put_disk(nbd_dev[i].disk); + } + return err; +} + +static void __exit nbd_cleanup(void) +{ + int i; + for (i = 0; i < MAX_NBD; i++) { + struct gendisk *disk = nbd_dev[i].disk; + if (disk) { + del_gendisk(disk); + blk_cleanup_queue(disk->queue); + put_disk(disk); + } + } + devfs_remove("nbd"); + unregister_blkdev(NBD_MAJOR, "nbd"); + 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"); + +#ifndef NDEBUG +module_param(debugflags, int, 0644); +MODULE_PARM_DESC(debugflags, "flags for controlling debug output"); +#endif -- cgit v1.2.1