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  */
   6
   7 #ifndef LINUX_NBD_H
   8 #define LINUX_NBD_H
   9
  10 #define NBD_SET_SOCK    _IO( 0xab, 0 )
  11 #define NBD_SET_BLKSIZE _IO( 0xab, 1 )
  12 #define NBD_SET_SIZE    _IO( 0xab, 2 )
  13 #define NBD_DO_IT       _IO( 0xab, 3 )
  14 #define NBD_CLEAR_SOCK  _IO( 0xab, 4 )
  15 #define NBD_CLEAR_QUE   _IO( 0xab, 5 )
  16 #define NBD_PRINT_DEBUG _IO( 0xab, 6 )
  17 #define NBD_SET_SIZE_BLOCKS     _IO( 0xab, 7 )
  18 #define NBD_DISCONNECT  _IO( 0xab, 8 )
  19
  20 #ifdef MAJOR_NR
  21
  22 #include <linux/locks.h>
  23 #include <asm/semaphore.h>
  24
  25 #define LOCAL_END_REQUEST
  26
  27 #include <linux/blk.h>
  28
  29 #ifdef PARANOIA
  30 extern int requests_in;
  31 extern int requests_out;
  32 #endif
  33
  34 static int
  35 nbd_end_request(struct request *req)
  36 {
  37         unsigned long flags;
  38         int ret = 0;
  39
  40 #ifdef PARANOIA
  41         requests_out++;
  42 #endif
  43         /*
  44          * This is a very dirty hack that we have to do to handle
  45          * merged requests because end_request stuff is a bit
  46          * broken. The fact we have to do this only if there
  47          * aren't errors looks even more silly.
  48          */
  49         if (!req->errors) {
  50                 req->sector += req->current_nr_sectors;
  51                 req->nr_sectors -= req->current_nr_sectors;
  52         }
  53
  54         spin_lock_irqsave(&io_request_lock, flags);
  55         if (end_that_request_first( req, !req->errors, "nbd" ))
  56                 goto out;
  57         ret = 1;
  58         end_that_request_last( req );
  59
  60 out:
  61         spin_unlock_irqrestore(&io_request_lock, flags);
  62         return ret;
  63 }
  64
  65 #define MAX_NBD 128
  66
  67 struct nbd_device {
  68         int refcnt;
  69         int flags;
  70         int harderror;          /* Code of hard error                   */
  71 #define NBD_READ_ONLY 0x0001
  72 #define NBD_WRITE_NOCHK 0x0002
  73         struct socket * sock;
  74         struct file * file;             /* If == NULL, device is not ready, yet */
  75         int magic;                      /* FIXME: not if debugging is off       */
  76         struct list_head queue_head;    /* Requests are added here...                   */
  77         struct semaphore queue_lock;
  78 };
  79 #endif
  80
  81 /* This now IS in some kind of include file...  */
  82
  83 /* These are send over network in request/reply magic field */
  84
  85 #define NBD_REQUEST_MAGIC 0x25609513
  86 #define NBD_REPLY_MAGIC 0x67446698
  87 /* Do *not* use magics: 0x12560953 0x96744668. */
  88
  89 /*
  90  * This is packet used for communication between client and
  91  * server. All data are in network byte order.
  92  */
  93 struct nbd_request {
  94         u32 magic;
  95         u32 type;       /* == READ || == WRITE  */
  96         char handle[8];
  97         u64 from;
  98         u32 len;
  99 }
 100 #ifdef __GNUC__
 101         __attribute__ ((packed))
 102 #endif
 103 ;
 104
 105 struct nbd_reply {
 106         u32 magic;
 107         u32 error;              /* 0 = ok, else error   */
 108         char handle[8];         /* handle you got from request  */
 109 };
 110 #endif