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 #define NBD_SET_TIMEOUT _IO( 0xab, 9 )
  30 #define NBD_SET_FLAGS   _IO( 0xab, 10)
  31
  32 enum {
  33         NBD_CMD_READ = 0,
  34         NBD_CMD_WRITE = 1,
  35         NBD_CMD_DISC = 2,
  36         /* there is a gap here to match userspace */
  37         NBD_CMD_TRIM = 4
  38 };
  39
  40 /* values for flags field */
  41 #define NBD_FLAG_HAS_FLAGS    (1 << 0) /* nbd-server supports flags */
  42 #define NBD_FLAG_READ_ONLY    (1 << 1) /* device is read-only */
  43 /* there is a gap here to match userspace */
  44 #define NBD_FLAG_SEND_TRIM    (1 << 5) /* send trim/discard */
  45
  46 #define nbd_cmd(req) ((req)->cmd[0])
  47
  48 /* userspace doesn't need the nbd_device structure */
  49 #ifdef __KERNEL__
  50
  51 #include <linux/wait.h>
  52 #include <linux/mutex.h>
  53
  54 struct request;
  55
  56 struct nbd_device {
  57         int flags;
  58         int harderror;          /* Code of hard error                   */
  59         struct socket * sock;
  60         struct file * file;     /* If == NULL, device is not ready, yet */
  61         int magic;
  62
  63         spinlock_t queue_lock;
  64         struct list_head queue_head;    /* Requests waiting result */
  65         struct request *active_req;
  66         wait_queue_head_t active_wq;
  67         struct list_head waiting_queue; /* Requests to be sent */
  68         wait_queue_head_t waiting_wq;
  69
  70         struct mutex tx_lock;
  71         struct gendisk *disk;
  72         int blksize;
  73         u64 bytesize;
  74         pid_t pid; /* pid of nbd-client, if attached */
  75         int xmit_timeout;
  76 };
  77
  78 #endif
  79
  80 /* These are sent over the network in the request/reply magic fields */
  81
  82 #define NBD_REQUEST_MAGIC 0x25609513
  83 #define NBD_REPLY_MAGIC 0x67446698
  84 /* Do *not* use magics: 0x12560953 0x96744668. */
  85
  86 /*
  87  * This is the packet used for communication between client and
  88  * server. All data are in network byte order.
  89  */
  90 struct nbd_request {
  91         __be32 magic;
  92         __be32 type;    /* == READ || == WRITE  */
  93         char handle[8];
  94         __be64 from;
  95         __be32 len;
  96 } __attribute__((packed));
  97
  98 /*
  99  * This is the reply packet that nbd-server sends back to the client after
 100  * it has completed an I/O request (or an error occurs).
 101  */
 102 struct nbd_reply {
 103         __be32 magic;
 104         __be32 error;           /* 0 = ok, else error   */
 105         char handle[8];         /* handle you got from request  */
 106 };
 107 #endif