ref: eddcd695d0c06c5e2dbef7c23c4998405857df59
dir: /lwext4/ext4_bcache.h/
/*
* Copyright (c) 2013 Grzegorz Kostka ([email protected])
* 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.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
/** @addtogroup lwext4
* @{
*/
/**
* @file ext4_bcache.h
* @brief Block cache allocator.
*/
#ifndef EXT4_BCACHE_H_
#define EXT4_BCACHE_H_
#include "ext4_config.h"
#include <stdint.h>
#include <stdbool.h>
/**@brief Single block descriptor.*/
struct ext4_block {
/**@brief Dirty flag.*/
bool dirty;
/**@brief Logical block ID*/
uint64_t lb_id;
/**@brief Cache id*/
uint32_t cache_id;
/**@brief Data buffer.*/
uint8_t *data;
};
/**@brief Block cache descriptor.*/
struct ext4_bcache {
/**@brief Item count in block cache*/
uint32_t cnt;
/**@brief Item size in block cache*/
uint32_t itemsize;
/**@brief Last recently used counter.*/
uint32_t lru_ctr;
/**@brief Reference count table (cnt).*/
uint32_t refctr[CONFIG_BLOCK_DEV_CACHE_SIZE];
/**@brief Last recently used ID table (cnt)*/
uint32_t lru_id[CONFIG_BLOCK_DEV_CACHE_SIZE];
/**@brief Writeback free delay mode table (cnt)*/
uint8_t free_delay[CONFIG_BLOCK_DEV_CACHE_SIZE];
/**@brief Logical block table (cnt).*/
uint64_t lba[CONFIG_BLOCK_DEV_CACHE_SIZE];
/**@brief Dirty mark (cnt).*/
bool dirty[CONFIG_BLOCK_DEV_CACHE_SIZE];
/**@brief Cache data buffers (cnt * itemsize)*/
uint8_t *data;
/**@brief Currently referenced datablocks*/
uint32_t ref_blocks;
/**@brief Maximum referenced datablocks*/
uint32_t max_ref_blocks;
};
/**@brief Static initializer of block cache structure.*/
#define EXT4_BCACHE_STATIC_INSTANCE(__name, __cnt, __itemsize) \
static uint8_t __name##_data[(__cnt) * (__itemsize)]; \
static struct ext4_bcache __name = { \
.cnt = __cnt, \
.itemsize = __itemsize, \
.lru_ctr = 0, \
.data = __name##_data, \
}
/**@brief Dynamic initialization of block cache.
* @param bc block cache descriptor
* @param cnt items count in block cache
* @param itemsize single item size (in bytes)
* @return standard error code*/
int ext4_bcache_init_dynamic(struct ext4_bcache *bc, uint32_t cnt,
uint32_t itemsize);
/**@brief Dynamic de-initialization of block cache.
* @param bc block cache descriptor
* @return standard error code*/
int ext4_bcache_fini_dynamic(struct ext4_bcache *bc);
/**@brief Allocate block from block cache memory.
* Unreferenced block allocation is based on LRU
* (Last Recently Used) algorithm.
* @param bc block cache descriptor
* @param b block to alloc
* @param is_new block is new (needs to be read)
* @return standard error code*/
int ext4_bcache_alloc(struct ext4_bcache *bc, struct ext4_block *b,
bool *is_new);
/**@brief Free block from cache memory (decrement reference counter).
* @param bc block cache descriptor
* @param b block to free
* @param cache writeback mode
* @return standard error code*/
int ext4_bcache_free(struct ext4_bcache *bc, struct ext4_block *b,
uint8_t free_delay);
/**@brief Return a full status of block cache.
* @param bc block cache descriptor
* @return full status*/
bool ext4_bcache_is_full(struct ext4_bcache *bc);
#endif /* EXT4_BCACHE_H_ */
/**
* @}
*/