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b277da0a8a
Clear QUEUE_FLAG_ADD_RANDOM in all block drivers that set
QUEUE_FLAG_NONROT.
Historically, all block devices have automatically made entropy
contributions. But as previously stated in commit e2e1a148
("block: add
sysfs knob for turning off disk entropy contributions"):
- On SSD disks, the completion times aren't as random as they
are for rotational drives. So it's questionable whether they
should contribute to the random pool in the first place.
- Calling add_disk_randomness() has a lot of overhead.
There are more reliable sources for randomness than non-rotational block
devices. From a security perspective it is better to err on the side of
caution than to allow entropy contributions from unreliable "random"
sources.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
927 lines
22 KiB
C
927 lines
22 KiB
C
/*
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* Network block device - make block devices work over TCP
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*
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* Note that you can not swap over this thing, yet. Seems to work but
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* deadlocks sometimes - you can not swap over TCP in general.
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*
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* Copyright 1997-2000, 2008 Pavel Machek <pavel@ucw.cz>
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* Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com>
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*
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* This file is released under GPLv2 or later.
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*
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* (part of code stolen from loop.c)
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*/
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#include <linux/major.h>
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#include <linux/blkdev.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/sched.h>
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#include <linux/fs.h>
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#include <linux/bio.h>
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#include <linux/stat.h>
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#include <linux/errno.h>
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#include <linux/file.h>
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#include <linux/ioctl.h>
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#include <linux/mutex.h>
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#include <linux/compiler.h>
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#include <linux/err.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <net/sock.h>
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#include <linux/net.h>
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#include <linux/kthread.h>
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#include <asm/uaccess.h>
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#include <asm/types.h>
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#include <linux/nbd.h>
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#define NBD_MAGIC 0x68797548
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#ifdef NDEBUG
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#define dprintk(flags, fmt...)
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#else /* NDEBUG */
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#define dprintk(flags, fmt...) do { \
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if (debugflags & (flags)) printk(KERN_DEBUG fmt); \
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} while (0)
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#define DBG_IOCTL 0x0004
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#define DBG_INIT 0x0010
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#define DBG_EXIT 0x0020
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#define DBG_BLKDEV 0x0100
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#define DBG_RX 0x0200
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#define DBG_TX 0x0400
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static unsigned int debugflags;
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#endif /* NDEBUG */
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static unsigned int nbds_max = 16;
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static struct nbd_device *nbd_dev;
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static int max_part;
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/*
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* Use just one lock (or at most 1 per NIC). Two arguments for this:
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* 1. Each NIC is essentially a synchronization point for all servers
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* accessed through that NIC so there's no need to have more locks
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* than NICs anyway.
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* 2. More locks lead to more "Dirty cache line bouncing" which will slow
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* down each lock to the point where they're actually slower than just
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* a single lock.
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* Thanks go to Jens Axboe and Al Viro for their LKML emails explaining this!
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*/
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static DEFINE_SPINLOCK(nbd_lock);
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#ifndef NDEBUG
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static const char *ioctl_cmd_to_ascii(int cmd)
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{
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switch (cmd) {
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case NBD_SET_SOCK: return "set-sock";
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case NBD_SET_BLKSIZE: return "set-blksize";
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case NBD_SET_SIZE: return "set-size";
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case NBD_SET_TIMEOUT: return "set-timeout";
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case NBD_SET_FLAGS: return "set-flags";
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case NBD_DO_IT: return "do-it";
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case NBD_CLEAR_SOCK: return "clear-sock";
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case NBD_CLEAR_QUE: return "clear-que";
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case NBD_PRINT_DEBUG: return "print-debug";
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case NBD_SET_SIZE_BLOCKS: return "set-size-blocks";
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case NBD_DISCONNECT: return "disconnect";
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case BLKROSET: return "set-read-only";
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case BLKFLSBUF: return "flush-buffer-cache";
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}
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return "unknown";
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}
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static const char *nbdcmd_to_ascii(int cmd)
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{
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switch (cmd) {
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case NBD_CMD_READ: return "read";
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case NBD_CMD_WRITE: return "write";
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case NBD_CMD_DISC: return "disconnect";
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case NBD_CMD_FLUSH: return "flush";
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case NBD_CMD_TRIM: return "trim/discard";
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}
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return "invalid";
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}
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#endif /* NDEBUG */
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static void nbd_end_request(struct request *req)
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{
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int error = req->errors ? -EIO : 0;
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struct request_queue *q = req->q;
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unsigned long flags;
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dprintk(DBG_BLKDEV, "%s: request %p: %s\n", req->rq_disk->disk_name,
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req, error ? "failed" : "done");
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spin_lock_irqsave(q->queue_lock, flags);
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__blk_end_request_all(req, error);
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spin_unlock_irqrestore(q->queue_lock, flags);
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}
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static void sock_shutdown(struct nbd_device *nbd, int lock)
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{
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/* Forcibly shutdown the socket causing all listeners
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* to error
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*
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* FIXME: This code is duplicated from sys_shutdown, but
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* there should be a more generic interface rather than
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* calling socket ops directly here */
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if (lock)
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mutex_lock(&nbd->tx_lock);
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if (nbd->sock) {
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dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
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kernel_sock_shutdown(nbd->sock, SHUT_RDWR);
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nbd->sock = NULL;
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}
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if (lock)
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mutex_unlock(&nbd->tx_lock);
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}
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static void nbd_xmit_timeout(unsigned long arg)
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{
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struct task_struct *task = (struct task_struct *)arg;
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printk(KERN_WARNING "nbd: killing hung xmit (%s, pid: %d)\n",
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task->comm, task->pid);
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force_sig(SIGKILL, task);
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}
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/*
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* Send or receive packet.
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*/
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static int sock_xmit(struct nbd_device *nbd, int send, void *buf, int size,
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int msg_flags)
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{
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struct socket *sock = nbd->sock;
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int result;
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struct msghdr msg;
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struct kvec iov;
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sigset_t blocked, oldset;
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unsigned long pflags = current->flags;
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if (unlikely(!sock)) {
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dev_err(disk_to_dev(nbd->disk),
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"Attempted %s on closed socket in sock_xmit\n",
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(send ? "send" : "recv"));
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return -EINVAL;
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}
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/* Allow interception of SIGKILL only
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* Don't allow other signals to interrupt the transmission */
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siginitsetinv(&blocked, sigmask(SIGKILL));
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sigprocmask(SIG_SETMASK, &blocked, &oldset);
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current->flags |= PF_MEMALLOC;
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do {
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sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC;
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iov.iov_base = buf;
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iov.iov_len = size;
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msg.msg_name = NULL;
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msg.msg_namelen = 0;
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msg.msg_control = NULL;
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msg.msg_controllen = 0;
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msg.msg_flags = msg_flags | MSG_NOSIGNAL;
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if (send) {
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struct timer_list ti;
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if (nbd->xmit_timeout) {
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init_timer(&ti);
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ti.function = nbd_xmit_timeout;
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ti.data = (unsigned long)current;
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ti.expires = jiffies + nbd->xmit_timeout;
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add_timer(&ti);
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}
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result = kernel_sendmsg(sock, &msg, &iov, 1, size);
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if (nbd->xmit_timeout)
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del_timer_sync(&ti);
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} else
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result = kernel_recvmsg(sock, &msg, &iov, 1, size,
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msg.msg_flags);
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if (signal_pending(current)) {
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siginfo_t info;
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printk(KERN_WARNING "nbd (pid %d: %s) got signal %d\n",
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task_pid_nr(current), current->comm,
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dequeue_signal_lock(current, ¤t->blocked, &info));
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result = -EINTR;
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sock_shutdown(nbd, !send);
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break;
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}
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if (result <= 0) {
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if (result == 0)
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result = -EPIPE; /* short read */
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break;
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}
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size -= result;
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buf += result;
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} while (size > 0);
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sigprocmask(SIG_SETMASK, &oldset, NULL);
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tsk_restore_flags(current, pflags, PF_MEMALLOC);
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return result;
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}
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static inline int sock_send_bvec(struct nbd_device *nbd, struct bio_vec *bvec,
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int flags)
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{
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int result;
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void *kaddr = kmap(bvec->bv_page);
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result = sock_xmit(nbd, 1, kaddr + bvec->bv_offset,
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bvec->bv_len, flags);
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kunmap(bvec->bv_page);
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return result;
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}
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/* always call with the tx_lock held */
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static int nbd_send_req(struct nbd_device *nbd, struct request *req)
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{
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int result, flags;
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struct nbd_request request;
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unsigned long size = blk_rq_bytes(req);
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memset(&request, 0, sizeof(request));
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request.magic = htonl(NBD_REQUEST_MAGIC);
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request.type = htonl(nbd_cmd(req));
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if (nbd_cmd(req) != NBD_CMD_FLUSH && nbd_cmd(req) != NBD_CMD_DISC) {
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request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
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request.len = htonl(size);
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}
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memcpy(request.handle, &req, sizeof(req));
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dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%uB)\n",
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nbd->disk->disk_name, req,
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nbdcmd_to_ascii(nbd_cmd(req)),
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(unsigned long long)blk_rq_pos(req) << 9,
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blk_rq_bytes(req));
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result = sock_xmit(nbd, 1, &request, sizeof(request),
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(nbd_cmd(req) == NBD_CMD_WRITE) ? MSG_MORE : 0);
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if (result <= 0) {
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dev_err(disk_to_dev(nbd->disk),
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"Send control failed (result %d)\n", result);
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goto error_out;
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}
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if (nbd_cmd(req) == NBD_CMD_WRITE) {
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struct req_iterator iter;
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struct bio_vec bvec;
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/*
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* we are really probing at internals to determine
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* whether to set MSG_MORE or not...
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*/
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rq_for_each_segment(bvec, req, iter) {
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flags = 0;
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if (!rq_iter_last(bvec, iter))
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flags = MSG_MORE;
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dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n",
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nbd->disk->disk_name, req, bvec.bv_len);
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result = sock_send_bvec(nbd, &bvec, flags);
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if (result <= 0) {
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dev_err(disk_to_dev(nbd->disk),
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"Send data failed (result %d)\n",
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result);
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goto error_out;
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}
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}
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}
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return 0;
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error_out:
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return -EIO;
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}
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static struct request *nbd_find_request(struct nbd_device *nbd,
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struct request *xreq)
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{
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struct request *req, *tmp;
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int err;
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err = wait_event_interruptible(nbd->active_wq, nbd->active_req != xreq);
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if (unlikely(err))
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goto out;
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spin_lock(&nbd->queue_lock);
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list_for_each_entry_safe(req, tmp, &nbd->queue_head, queuelist) {
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if (req != xreq)
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continue;
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list_del_init(&req->queuelist);
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spin_unlock(&nbd->queue_lock);
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return req;
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}
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spin_unlock(&nbd->queue_lock);
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err = -ENOENT;
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out:
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return ERR_PTR(err);
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}
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static inline int sock_recv_bvec(struct nbd_device *nbd, struct bio_vec *bvec)
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{
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int result;
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void *kaddr = kmap(bvec->bv_page);
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result = sock_xmit(nbd, 0, kaddr + bvec->bv_offset, bvec->bv_len,
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MSG_WAITALL);
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kunmap(bvec->bv_page);
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return result;
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}
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|
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/* NULL returned = something went wrong, inform userspace */
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static struct request *nbd_read_stat(struct nbd_device *nbd)
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{
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int result;
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struct nbd_reply reply;
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struct request *req;
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reply.magic = 0;
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result = sock_xmit(nbd, 0, &reply, sizeof(reply), MSG_WAITALL);
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if (result <= 0) {
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dev_err(disk_to_dev(nbd->disk),
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"Receive control failed (result %d)\n", result);
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goto harderror;
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}
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if (ntohl(reply.magic) != NBD_REPLY_MAGIC) {
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dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n",
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(unsigned long)ntohl(reply.magic));
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result = -EPROTO;
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goto harderror;
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}
|
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req = nbd_find_request(nbd, *(struct request **)reply.handle);
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if (IS_ERR(req)) {
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result = PTR_ERR(req);
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if (result != -ENOENT)
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|
goto harderror;
|
|
|
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dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%p)\n",
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reply.handle);
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result = -EBADR;
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goto harderror;
|
|
}
|
|
|
|
if (ntohl(reply.error)) {
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dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n",
|
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ntohl(reply.error));
|
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req->errors++;
|
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return req;
|
|
}
|
|
|
|
dprintk(DBG_RX, "%s: request %p: got reply\n",
|
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nbd->disk->disk_name, req);
|
|
if (nbd_cmd(req) == NBD_CMD_READ) {
|
|
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;
|
|
}
|
|
dprintk(DBG_RX, "%s: request %p: got %d bytes data\n",
|
|
nbd->disk->disk_name, 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(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(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(req);
|
|
}
|
|
}
|
|
|
|
|
|
static void nbd_handle_req(struct nbd_device *nbd, struct request *req)
|
|
{
|
|
if (req->cmd_type != REQ_TYPE_FS)
|
|
goto error_out;
|
|
|
|
nbd_cmd(req) = NBD_CMD_READ;
|
|
if (rq_data_dir(req) == WRITE) {
|
|
if ((req->cmd_flags & REQ_DISCARD)) {
|
|
WARN_ON(!(nbd->flags & NBD_FLAG_SEND_TRIM));
|
|
nbd_cmd(req) = NBD_CMD_TRIM;
|
|
} else
|
|
nbd_cmd(req) = NBD_CMD_WRITE;
|
|
if (nbd->flags & NBD_FLAG_READ_ONLY) {
|
|
dev_err(disk_to_dev(nbd->disk),
|
|
"Write on read-only\n");
|
|
goto error_out;
|
|
}
|
|
}
|
|
|
|
if (req->cmd_flags & REQ_FLUSH) {
|
|
BUG_ON(unlikely(blk_rq_sectors(req)));
|
|
nbd_cmd(req) = NBD_CMD_FLUSH;
|
|
}
|
|
|
|
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(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(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);
|
|
|
|
dprintk(DBG_BLKDEV, "%s: request %p: dequeued (flags=%x)\n",
|
|
req->rq_disk->disk_name, req, req->cmd_type);
|
|
|
|
nbd = req->rq_disk->private_data;
|
|
|
|
BUG_ON(nbd->magic != NBD_MAGIC);
|
|
|
|
if (unlikely(!nbd->sock)) {
|
|
dev_err(disk_to_dev(nbd->disk),
|
|
"Attempted send on closed socket\n");
|
|
req->errors++;
|
|
nbd_end_request(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_SPECIAL;
|
|
nbd_cmd(&sreq) = NBD_CMD_DISC;
|
|
|
|
/* 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_create(nbd_thread, nbd, "%s",
|
|
nbd->disk->disk_name);
|
|
if (IS_ERR(thread)) {
|
|
mutex_lock(&nbd->tx_lock);
|
|
return PTR_ERR(thread);
|
|
}
|
|
wake_up_process(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)
|
|
ioctl_by_bdev(bdev, BLKRRPART, 0);
|
|
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);
|
|
|
|
/* Anyone capable of this syscall can do *real bad* things */
|
|
dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n",
|
|
nbd->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg);
|
|
|
|
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;
|
|
}
|
|
|
|
nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL);
|
|
if (!nbd_dev)
|
|
return -ENOMEM;
|
|
|
|
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;
|
|
|
|
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;
|
|
disk->queue->limits.max_discard_sectors = 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);
|
|
dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags);
|
|
|
|
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)");
|
|
#ifndef NDEBUG
|
|
module_param(debugflags, int, 0644);
|
|
MODULE_PARM_DESC(debugflags, "flags for controlling debug output");
|
|
#endif
|