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nbd.h

/*
 * 1999 Copyright (C) Pavel Machek, pavel@ucw.cz. This code is GPL.
 * 1999/11/04 Copyright (C) 1999 VMware, Inc. (Regis "HPReg" Duchesne)
 *            Made nbd_end_request() use the io_request_lock
 * 2001 Copyright (C) Steven Whitehouse
 *            New nbd_end_request() for compatibility with new linux block
 *            layer code.
 * 2003/06/24 Louis D. Langholtz <ldl@aros.net>
 *            Removed unneeded blksize_bits field from nbd_device struct.
 *            Cleanup PARANOIA usage & code.
 * 2004/02/19 Paul Clements
 *            Removed PARANOIA, plus various cleanup and comments
 */

#ifndef LINUX_NBD_H
#define LINUX_NBD_H

#define NBD_SET_SOCK    _IO( 0xab, 0 )
#define NBD_SET_BLKSIZE _IO( 0xab, 1 )
#define NBD_SET_SIZE    _IO( 0xab, 2 )
#define NBD_DO_IT _IO( 0xab, 3 )
#define NBD_CLEAR_SOCK  _IO( 0xab, 4 )
#define NBD_CLEAR_QUE   _IO( 0xab, 5 )
#define NBD_PRINT_DEBUG _IO( 0xab, 6 )
#define NBD_SET_SIZE_BLOCKS   _IO( 0xab, 7 )
#define NBD_DISCONNECT  _IO( 0xab, 8 )

enum {
      NBD_CMD_READ = 0,
      NBD_CMD_WRITE = 1,
      NBD_CMD_DISC = 2
};

#define nbd_cmd(req) ((req)->cmd[0])
#define MAX_NBD 128

/* userspace doesn't need the nbd_device structure */
#ifdef __KERNEL__

/* values for flags field */
#define NBD_READ_ONLY 0x0001
#define NBD_WRITE_NOCHK 0x0002

struct nbd_device {
      int flags;
      int harderror;          /* Code of hard error               */
      struct socket * sock;
      struct file * file;     /* If == NULL, device is not ready, yet   */
      int magic;
      spinlock_t queue_lock;
      struct list_head queue_head;/* Requests are added here...   */
      struct semaphore tx_lock;
      struct gendisk *disk;
      int blksize;
      u64 bytesize;
};

#endif

/* These are sent over the network in the request/reply magic fields */

#define NBD_REQUEST_MAGIC 0x25609513
#define NBD_REPLY_MAGIC 0x67446698
/* Do *not* use magics: 0x12560953 0x96744668. */

/*
 * This is the packet used for communication between client and
 * server. All data are in network byte order.
 */
00070 struct nbd_request {
      u32 magic;
      u32 type;   /* == READ || == WRITE  */
      char handle[8];
      u64 from;
      u32 len;
}
#ifdef __GNUC__
      __attribute__ ((packed))
#endif
;

/*
 * This is the reply packet that nbd-server sends back to the client after
 * it has completed an I/O request (or an error occurs).
 */
00086 struct nbd_reply {
      u32 magic;
      u32 error;        /* 0 = ok, else error   */
      char handle[8];         /* handle you got from request      */
};
#endif

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