/*
* Network block device - make block devices work over TCP
*
* Note that you can not swap over this thing, yet. Seems to work but
* deadlocks sometimes - you can not swap over TCP in general.
*
* Copyright 1997-2000, 2008 Pavel Machek <pavel@ucw.cz>
* Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com>
*
* This file is released under GPLv2 or later.
*
* (part of code stolen from loop.c)
*/
#include <linux/major.h>
#include <linux/blkdev.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/bio.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/file.h>
#include <linux/ioctl.h>
#include <linux/mutex.h>
#include <linux/compiler.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <net/sock.h>
#include <linux/net.h>
#include <linux/kthread.h>
#include <linux/types.h>
#include <linux/debugfs.h>
#include <linux/blk-mq.h>
#include <linux/uaccess.h>
#include <asm/types.h>
#include <linux/nbd.h>
static DEFINE_IDR(nbd_index_idr);
static DEFINE_MUTEX(nbd_index_mutex);
struct nbd_sock {
struct socket *sock;
struct mutex tx_lock;
};
#define NBD_TIMEDOUT 0
#define NBD_DISCONNECT_REQUESTED 1
#define NBD_DISCONNECTED 2
#define NBD_RUNNING 3
struct nbd_device {
u32 flags;
unsigned long runtime_flags;
struct nbd_sock **socks;
int magic;
struct blk_mq_tag_set tag_set;
struct mutex config_lock;
struct gendisk *disk;
int num_connections;
atomic_t recv_threads;
wait_queue_head_t recv_wq;
loff_t blksize;
loff_t bytesize;
struct task_struct *task_recv;
struct task_struct *task_setup;
#if IS_ENABLED(CONFIG_DEBUG_FS)
struct dentry *dbg_dir;
#endif
};
struct nbd_cmd {
struct nbd_device *nbd;
struct completion send_complete;
};
#if IS_ENABLED(CONFIG_DEBUG_FS)
static struct dentry *nbd_dbg_dir;
#endif
#define nbd_name(nbd) ((nbd)->disk->disk_name)
#define NBD_MAGIC 0x68797548
static unsigned int nbds_max = 16;
static int max_part;
static struct workqueue_struct *recv_workqueue;
static int part_shift;
static int nbd_dev_dbg_init(struct nbd_device *nbd);
static void nbd_dev_dbg_close(struct nbd_device *nbd);
static inline struct device *nbd_to_dev(struct nbd_device *nbd)
{
return disk_to_dev(nbd->disk);
}
static bool nbd_is_connected(struct nbd_device *nbd)
{
return !!nbd->task_recv;
}
static const char *nbdcmd_to_ascii(int cmd)
{
switch (cmd) {
case NBD_CMD_READ: return "read";
case NBD_CMD_WRITE: return "write";
case NBD_CMD_DISC: return "disconnect";
case NBD_CMD_FLUSH: return "flush";
case NBD_CMD_TRIM: return "trim/discard";
}
return "invalid";
}
static int nbd_size_clear(struct nbd_device *nbd, struct block_device *bdev)
{
bd_set_size(bdev, 0);
set_capacity(nbd->disk, 0);
kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
return 0;
}
static void nbd_size_update(struct nbd_device *nbd, struct block_device *bdev)
{
blk_queue_logical_block_size(nbd->disk->queue, nbd->blksize);
blk_queue_physical_block_size(nbd->disk->queue, nbd->blksize);
bd_set_size(bdev, nbd->bytesize);
set_capacity(nbd->disk, nbd->bytesize >> 9);
kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHAN