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linux/nbd.h 源文件

• 2017 年 06 月 13 日 • Linux开发

linux/nbd.h源代码

/*
 * 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

#include <linux/types.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 )
#define NBD_SET_TIMEOUT _IO( 0xab, 9 )
#define NBD_SET_FLAGS   _IO( 0xab, 10)

enum {
    NBD_CMD_READ = 0,
    NBD_CMD_WRITE = 1,
    NBD_CMD_DISC = 2,
    NBD_CMD_FLUSH = 3,
    NBD_CMD_TRIM = 4
};

/* values for flags field */
#define NBD_FLAG_HAS_FLAGS    (1 << 0) /* nbd-server supports flags */
#define NBD_FLAG_READ_ONLY    (1 << 1) /* device is read-only */
#define NBD_FLAG_SEND_FLUSH   (1 << 2) /* can flush writeback cache */
/* there is a gap here to match userspace */
#define NBD_FLAG_SEND_TRIM    (1 << 5) /* send trim/discard */

/* userspace doesn't need the nbd_device structure */

/* 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.
 */
struct nbd_request {
    __be32 magic;
    __be32 type;    /* == READ || == WRITE     */
    char handle[8];
    __be64 from;
    __be32 len;
} __attribute__((packed));

/*
 * 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).
 */
struct nbd_reply {
    __be32 magic;
    __be32 error;        /* 0 = ok, else error    */
    char handle[8];        /* handle you got from request    */
};
#endif /* LINUX_NBD_H */
标签: Linux, nbd, C
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