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/*
* Copyright (c) 2007, XenSource Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of XenSource Inc. nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
* OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Some notes on the tap_disk interface:
*
* tap_disk aims to provide a generic interface to easily implement new
* types of image accessors. The structure-of-function-calls is similar
* to disk interfaces used in qemu/denali/etc, with the significant
* difference being the expectation of asynchronous rather than synchronous
* I/O. The asynchronous interface is intended to allow lots of requests to
* be pipelined through a disk, without the disk requiring any of its own
* threads of control. As such, a batch of requests is delivered to the disk
* using:
*
* td_queue_[read,write]()
*
* and passing in a completion callback, which the disk is responsible for
* tracking. Disks should transform these requests as necessary and return
* the resulting iocbs to tapdisk using td_prep_[read,write]() and
* td_queue_tiocb().
*
* NOTE: tapdisk uses the number of sectors submitted per request as a
* ref count. Plugins must use the callback function to communicate the
* completion -- or error -- of every sector submitted to them.
*
* td_get_parent_id returns:
* 0 if parent id successfully retrieved
* TD_NO_PARENT if no parent exists
* -errno on error
*/
#ifndef _TAPDISK_H_
#define _TAPDISK_H_
#include <time.h>
#include <stdint.h>
#include "list.h"
#include "blktaplib.h"
#include "tapdisk-log.h"
#include "tapdisk-utils.h"
#define DPRINTF(_f, _a...) syslog(LOG_INFO, _f, ##_a)
#define EPRINTF(_f, _a...) syslog(LOG_ERR, "tap-err:%s: " _f, __func__, ##_a)
#define PERROR(_f, _a...) EPRINTF(_f ": %s", ##_a, strerror(errno))
#define MAX_SEGMENTS_PER_REQ 11
#define SECTOR_SHIFT 9
#define DEFAULT_SECTOR_SIZE 512
#define TAPDISK_DATA_REQUESTS (MAX_REQUESTS * MAX_SEGMENTS_PER_REQ)
//#define BLK_NOT_ALLOCATED (-99)
#define TD_NO_PARENT 1
#define MAX_RAMDISK_SIZE 1024000 /*500MB disk limit*/
#define TD_OP_READ 0
#define TD_OP_WRITE 1
#define TD_OPEN_QUIET 0x00001
#define TD_OPEN_QUERY 0x00002
#define TD_OPEN_RDONLY 0x00004
#define TD_OPEN_STRICT 0x00008
#define TD_OPEN_SHAREABLE 0x00010
#define TD_OPEN_ADD_CACHE 0x00020
#define TD_OPEN_VHD_INDEX 0x00040
#define TD_OPEN_LOG_DIRTY 0x00080
#define TD_CREATE_SPARSE 0x00001
#define TD_CREATE_MULTITYPE 0x00002
#define td_flag_set(word, flag) ((word) |= (flag))
#define td_flag_clear(word, flag) ((word) &= ~(flag))
#define td_flag_test(word, flag) ((word) & (flag))
typedef uint16_t td_uuid_t;
typedef uint32_t td_flag_t;
typedef uint64_t td_sector_t;
typedef struct td_disk_id td_disk_id_t;
typedef struct td_disk_info td_disk_info_t;
typedef struct td_request td_request_t;
typedef struct td_driver_handle td_driver_t;
typedef struct td_image_handle td_image_t;
struct td_disk_id {
char *name;
int drivertype;
};
struct td_disk_info {
td_sector_t size;
uint64_t sector_size;
uint32_t info;
};
struct td_request {
int op;
char *buf;
td_sector_t sec;
int secs;
uint8_t blocked; /* blocked on a dependency */
td_image_t *image;
void * /*td_callback_t*/ cb;
void *cb_data;
uint64_t id;
int sidx;
void *private;
#ifdef MEMSHR
uint64_t memshr_hnd;
#endif
};
/*
* Prototype of the callback to activate as requests complete.
*/
typedef void (*td_callback_t)(td_request_t, int);
/*
* Structure describing the interface to a virtual disk implementation.
* See note at the top of this file describing this interface.
*/
struct tap_disk {
const char *disk_type;
td_flag_t flags;
int private_data_size;
int (*td_open) (td_driver_t *, const char *, td_flag_t);
int (*td_close) (td_driver_t *);
int (*td_get_parent_id) (td_driver_t *, td_disk_id_t *);
int (*td_validate_parent) (td_driver_t *, td_driver_t *, td_flag_t);
void (*td_queue_read) (td_driver_t *, td_request_t);
void (*td_queue_write) (td_driver_t *, td_request_t);
void (*td_debug) (td_driver_t *);
};
#endif
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