include/linux/nbd.h

   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
  30 enum {
  31         NBD_CMD_READ = 0,
  32         NBD_CMD_WRITE = 1,
  33         NBD_CMD_DISC = 2
  34 };
  35
  36 #define nbd_cmd(req) ((req)->cmd[0])
  37 #define MAX_NBD 128
  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
  49 struct request;
  50
  51 struct 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 are added here...       */
  60         struct request *active_req;
  61         wait_queue_head_t active_wq;
  62
  63         struct mutex tx_lock;
  64         struct gendisk *disk;
  65         int blksize;
  66         u64 bytesize;
  67         pid_t pid; /* pid of nbd-client, if attached */
  68 };
  69
  70 #endif
  71
  72 /* These are sent over the network in the request/reply magic fields */
  73
  74 #define NBD_REQUEST_MAGIC 0x25609513
  75 #define NBD_REPLY_MAGIC 0x67446698
  76 /* Do *not* use magics: 0x12560953 0x96744668. */
  77
  78 /*
  79  * This is the packet used for communication between client and
  80  * server. All data are in network byte order.
  81  */
  82 struct nbd_request {
  83         __be32 magic;
  84         __be32 type;    /* == READ || == WRITE  */
  85         char handle[8];
  86         __be64 from;
  87         __be32 len;
  88 }
  89 #ifdef __GNUC__
  90         __attribute__ ((packed))
  91 #endif
  92 ;
  93
  94 /*
  95  * This is the reply packet that nbd-server sends back to the client after
  96  * it has completed an I/O request (or an error occurs).
  97  */
  98 struct nbd_reply {
  99         __be32 magic;
 100         __be32 error;           /* 0 = ok, else error   */
 101         char handle[8];         /* handle you got from request  */
 102 };
 103 #endif