linux/include/linux/nbd.h
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   1/*
   2 * 1999 Copyright (C) Pavel Machek, pavel@ucw.cz. This code is GPL.
   3 * 1999/11/04 Copyright (C) 1999 VMware, Inc. (Regis "HPReg" Duchesne)
   4 *            Made nbd_end_request() use the io_request_lock
   5 * 2001 Copyright (C) Steven Whitehouse
   6 *            New nbd_end_request() for compatibility with new linux block
   7 *            layer code.
   8 * 2003/06/24 Louis D. Langholtz <ldl@aros.net>
   9 *            Removed unneeded blksize_bits field from nbd_device struct.
  10 *            Cleanup PARANOIA usage & code.
  11 * 2004/02/19 Paul Clements
  12 *            Removed PARANOIA, plus various cleanup and comments
  13 */
  14
  15#ifndef LINUX_NBD_H
  16#define LINUX_NBD_H
  17
  18#include <linux/types.h>
  19
  20#define NBD_SET_SOCK    _IO( 0xab, 0 )
  21#define NBD_SET_BLKSIZE _IO( 0xab, 1 )
  22#define NBD_SET_SIZE    _IO( 0xab, 2 )
  23#define NBD_DO_IT       _IO( 0xab, 3 )
  24#define NBD_CLEAR_SOCK  _IO( 0xab, 4 )
  25#define NBD_CLEAR_QUE   _IO( 0xab, 5 )
  26#define NBD_PRINT_DEBUG _IO( 0xab, 6 )
  27#define NBD_SET_SIZE_BLOCKS     _IO( 0xab, 7 )
  28#define NBD_DISCONNECT  _IO( 0xab, 8 )
  29#define NBD_SET_TIMEOUT _IO( 0xab, 9 )
  30
  31enum {
  32        NBD_CMD_READ = 0,
  33        NBD_CMD_WRITE = 1,
  34        NBD_CMD_DISC = 2
  35};
  36
  37#define nbd_cmd(req) ((req)->cmd[0])
  38
  39/* userspace doesn't need the nbd_device structure */
  40#ifdef __KERNEL__
  41
  42#include <linux/wait.h>
  43#include <linux/mutex.h>
  44
  45/* values for flags field */
  46#define NBD_READ_ONLY 0x0001
  47#define NBD_WRITE_NOCHK 0x0002
  48
  49struct request;
  50
  51struct nbd_device {
  52        int flags;
  53        int harderror;          /* Code of hard error                   */
  54        struct socket * sock;
  55        struct file * file;     /* If == NULL, device is not ready, yet */
  56        int magic;
  57
  58        spinlock_t queue_lock;
  59        struct list_head queue_head;    /* Requests waiting result */
  60        struct request *active_req;
  61        wait_queue_head_t active_wq;
  62        struct list_head waiting_queue; /* Requests to be sent */
  63        wait_queue_head_t waiting_wq;
  64
  65        struct mutex tx_lock;
  66        struct gendisk *disk;
  67        int blksize;
  68        u64 bytesize;
  69        pid_t pid; /* pid of nbd-client, if attached */
  70        int xmit_timeout;
  71};
  72
  73#endif
  74
  75/* These are sent over the network in the request/reply magic fields */
  76
  77#define NBD_REQUEST_MAGIC 0x25609513
  78#define NBD_REPLY_MAGIC 0x67446698
  79/* Do *not* use magics: 0x12560953 0x96744668. */
  80
  81/*
  82 * This is the packet used for communication between client and
  83 * server. All data are in network byte order.
  84 */
  85struct nbd_request {
  86        __be32 magic;
  87        __be32 type;    /* == READ || == WRITE  */
  88        char handle[8];
  89        __be64 from;
  90        __be32 len;
  91} __attribute__((packed));
  92
  93/*
  94 * This is the reply packet that nbd-server sends back to the client after
  95 * it has completed an I/O request (or an error occurs).
  96 */
  97struct nbd_reply {
  98        __be32 magic;
  99        __be32 error;           /* 0 = ok, else error   */
 100        char handle[8];         /* handle you got from request  */
 101};
 102#endif
 103
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