![Linus Torvalds](/assets/img/avatar_default.png)
This was entirely automated, using the script by Al: PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>' sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \ $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h) to do the replacement at the end of the merge window. Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1154 lines
27 KiB
C
1154 lines
27 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 <linux/types.h>
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#include <linux/debugfs.h>
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#include <linux/blk-mq.h>
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#include <linux/uaccess.h>
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#include <asm/types.h>
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#include <linux/nbd.h>
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struct nbd_sock {
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struct socket *sock;
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struct mutex tx_lock;
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};
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#define NBD_TIMEDOUT 0
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#define NBD_DISCONNECT_REQUESTED 1
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#define NBD_DISCONNECTED 2
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#define NBD_RUNNING 3
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struct nbd_device {
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u32 flags;
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unsigned long runtime_flags;
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struct nbd_sock **socks;
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int magic;
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struct blk_mq_tag_set tag_set;
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struct mutex config_lock;
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struct gendisk *disk;
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int num_connections;
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atomic_t recv_threads;
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wait_queue_head_t recv_wq;
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loff_t blksize;
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loff_t bytesize;
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struct task_struct *task_recv;
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struct task_struct *task_setup;
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#if IS_ENABLED(CONFIG_DEBUG_FS)
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struct dentry *dbg_dir;
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#endif
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};
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struct nbd_cmd {
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struct nbd_device *nbd;
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struct completion send_complete;
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};
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#if IS_ENABLED(CONFIG_DEBUG_FS)
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static struct dentry *nbd_dbg_dir;
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#endif
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#define nbd_name(nbd) ((nbd)->disk->disk_name)
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#define NBD_MAGIC 0x68797548
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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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static inline struct device *nbd_to_dev(struct nbd_device *nbd)
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{
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return disk_to_dev(nbd->disk);
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}
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static bool nbd_is_connected(struct nbd_device *nbd)
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{
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return !!nbd->task_recv;
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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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static int nbd_size_clear(struct nbd_device *nbd, struct block_device *bdev)
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{
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bdev->bd_inode->i_size = 0;
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set_capacity(nbd->disk, 0);
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kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
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return 0;
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}
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static void nbd_size_update(struct nbd_device *nbd, struct block_device *bdev)
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{
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if (!nbd_is_connected(nbd))
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return;
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bdev->bd_inode->i_size = nbd->bytesize;
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set_capacity(nbd->disk, nbd->bytesize >> 9);
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kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
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}
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static int nbd_size_set(struct nbd_device *nbd, struct block_device *bdev,
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loff_t blocksize, loff_t nr_blocks)
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{
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int ret;
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ret = set_blocksize(bdev, blocksize);
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if (ret)
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return ret;
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nbd->blksize = blocksize;
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nbd->bytesize = blocksize * nr_blocks;
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nbd_size_update(nbd, bdev);
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return 0;
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}
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static void nbd_end_request(struct nbd_cmd *cmd)
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{
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struct nbd_device *nbd = cmd->nbd;
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struct request *req = blk_mq_rq_from_pdu(cmd);
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int error = req->errors ? -EIO : 0;
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dev_dbg(nbd_to_dev(nbd), "request %p: %s\n", cmd,
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error ? "failed" : "done");
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blk_mq_complete_request(req, error);
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}
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/*
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* Forcibly shutdown the socket causing all listeners to error
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*/
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static void sock_shutdown(struct nbd_device *nbd)
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{
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int i;
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if (nbd->num_connections == 0)
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return;
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if (test_and_set_bit(NBD_DISCONNECTED, &nbd->runtime_flags))
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return;
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for (i = 0; i < nbd->num_connections; i++) {
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struct nbd_sock *nsock = nbd->socks[i];
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mutex_lock(&nsock->tx_lock);
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kernel_sock_shutdown(nsock->sock, SHUT_RDWR);
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mutex_unlock(&nsock->tx_lock);
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}
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dev_warn(disk_to_dev(nbd->disk), "shutting down sockets\n");
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}
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static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
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bool reserved)
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{
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struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
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struct nbd_device *nbd = cmd->nbd;
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dev_err(nbd_to_dev(nbd), "Connection timed out, shutting down connection\n");
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set_bit(NBD_TIMEDOUT, &nbd->runtime_flags);
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req->errors++;
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/*
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* If our disconnect packet times out then we're already holding the
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* config_lock and could deadlock here, so just set an error and return,
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* we'll handle shutting everything down later.
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*/
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if (req->cmd_type == REQ_TYPE_DRV_PRIV)
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return BLK_EH_HANDLED;
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mutex_lock(&nbd->config_lock);
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sock_shutdown(nbd);
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mutex_unlock(&nbd->config_lock);
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return BLK_EH_HANDLED;
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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 index, int send, void *buf,
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int size, int msg_flags)
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{
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struct socket *sock = nbd->socks[index]->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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unsigned long pflags = current->flags;
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if (unlikely(!sock)) {
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dev_err_ratelimited(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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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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result = kernel_sendmsg(sock, &msg, &iov, 1, size);
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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 (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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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, int index,
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struct bio_vec *bvec, 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, index, 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_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
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{
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struct request *req = blk_mq_rq_from_pdu(cmd);
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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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struct bio *bio;
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u32 type;
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u32 tag = blk_mq_unique_tag(req);
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if (req_op(req) == REQ_OP_DISCARD)
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type = NBD_CMD_TRIM;
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else if (req_op(req) == REQ_OP_FLUSH)
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type = NBD_CMD_FLUSH;
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else if (rq_data_dir(req) == WRITE)
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type = NBD_CMD_WRITE;
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else
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type = NBD_CMD_READ;
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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(type);
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if (type != NBD_CMD_FLUSH) {
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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, &tag, sizeof(tag));
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dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n",
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cmd, nbdcmd_to_ascii(type),
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(unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req));
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result = sock_xmit(nbd, index, 1, &request, sizeof(request),
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(type == NBD_CMD_WRITE) ? MSG_MORE : 0);
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if (result <= 0) {
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dev_err_ratelimited(disk_to_dev(nbd->disk),
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"Send control failed (result %d)\n", result);
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return -EIO;
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}
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if (type != NBD_CMD_WRITE)
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return 0;
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flags = 0;
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bio = req->bio;
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while (bio) {
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struct bio *next = bio->bi_next;
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struct bvec_iter iter;
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struct bio_vec bvec;
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bio_for_each_segment(bvec, bio, iter) {
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bool is_last = !next && bio_iter_last(bvec, iter);
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if (is_last)
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flags = MSG_MORE;
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dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n",
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cmd, bvec.bv_len);
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result = sock_send_bvec(nbd, index, &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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return -EIO;
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}
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/*
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* The completion might already have come in,
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* so break for the last one instead of letting
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* the iterator do it. This prevents use-after-free
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* of the bio.
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*/
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if (is_last)
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break;
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}
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bio = next;
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}
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return 0;
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}
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static inline int sock_recv_bvec(struct nbd_device *nbd, int index,
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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, index, 0, kaddr + bvec->bv_offset,
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bvec->bv_len, MSG_WAITALL);
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kunmap(bvec->bv_page);
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return result;
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}
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/* NULL returned = something went wrong, inform userspace */
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static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
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{
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int result;
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struct nbd_reply reply;
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struct nbd_cmd *cmd;
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struct request *req = NULL;
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u16 hwq;
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u32 tag;
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reply.magic = 0;
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result = sock_xmit(nbd, index, 0, &reply, sizeof(reply), MSG_WAITALL);
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if (result <= 0) {
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if (!test_bit(NBD_DISCONNECTED, &nbd->runtime_flags) &&
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!test_bit(NBD_DISCONNECT_REQUESTED, &nbd->runtime_flags))
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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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return ERR_PTR(result);
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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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return ERR_PTR(-EPROTO);
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}
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memcpy(&tag, reply.handle, sizeof(u32));
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hwq = blk_mq_unique_tag_to_hwq(tag);
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if (hwq < nbd->tag_set.nr_hw_queues)
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req = blk_mq_tag_to_rq(nbd->tag_set.tags[hwq],
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blk_mq_unique_tag_to_tag(tag));
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if (!req || !blk_mq_request_started(req)) {
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dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%d) %p\n",
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tag, req);
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return ERR_PTR(-ENOENT);
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}
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cmd = blk_mq_rq_to_pdu(req);
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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 cmd;
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}
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dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", cmd);
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if (rq_data_dir(req) != WRITE) {
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struct req_iterator iter;
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struct bio_vec bvec;
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rq_for_each_segment(bvec, req, iter) {
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result = sock_recv_bvec(nbd, index, &bvec);
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if (result <= 0) {
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dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
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result);
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req->errors++;
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return cmd;
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}
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dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n",
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cmd, bvec.bv_len);
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}
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} else {
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/* See the comment in nbd_queue_rq. */
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wait_for_completion(&cmd->send_complete);
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}
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return cmd;
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}
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static ssize_t pid_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct gendisk *disk = dev_to_disk(dev);
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struct nbd_device *nbd = (struct nbd_device *)disk->private_data;
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return sprintf(buf, "%d\n", task_pid_nr(nbd->task_recv));
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}
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static struct device_attribute pid_attr = {
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.attr = { .name = "pid", .mode = S_IRUGO},
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.show = pid_show,
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};
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struct recv_thread_args {
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struct work_struct work;
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struct nbd_device *nbd;
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int index;
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};
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static void recv_work(struct work_struct *work)
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{
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struct recv_thread_args *args = container_of(work,
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struct recv_thread_args,
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work);
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struct nbd_device *nbd = args->nbd;
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struct nbd_cmd *cmd;
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int ret = 0;
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BUG_ON(nbd->magic != NBD_MAGIC);
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while (1) {
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cmd = nbd_read_stat(nbd, args->index);
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if (IS_ERR(cmd)) {
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ret = PTR_ERR(cmd);
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break;
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}
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nbd_end_request(cmd);
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}
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|
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/*
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* We got an error, shut everybody down if this wasn't the result of a
|
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* disconnect request.
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*/
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if (ret && !test_bit(NBD_DISCONNECT_REQUESTED, &nbd->runtime_flags))
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sock_shutdown(nbd);
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atomic_dec(&nbd->recv_threads);
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wake_up(&nbd->recv_wq);
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}
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static void nbd_clear_req(struct request *req, void *data, bool reserved)
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{
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struct nbd_cmd *cmd;
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if (!blk_mq_request_started(req))
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return;
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cmd = blk_mq_rq_to_pdu(req);
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req->errors++;
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nbd_end_request(cmd);
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}
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static void nbd_clear_que(struct nbd_device *nbd)
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{
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BUG_ON(nbd->magic != NBD_MAGIC);
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blk_mq_tagset_busy_iter(&nbd->tag_set, nbd_clear_req, NULL);
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dev_dbg(disk_to_dev(nbd->disk), "queue cleared\n");
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}
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|
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static void nbd_handle_cmd(struct nbd_cmd *cmd, int index)
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{
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struct request *req = blk_mq_rq_from_pdu(cmd);
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struct nbd_device *nbd = cmd->nbd;
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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)");
|