2 * Copyright (c) 2013 Grzegorz Kostka (kostka.grzegorz@gmail.com)
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
9 * - Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * - The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 /** @addtogroup lwext4
34 * @brief Block cache allocator.
37 #ifndef EXT4_BCACHE_H_
38 #define EXT4_BCACHE_H_
40 #include "ext4_config.h"
45 /**@brief Single block descriptor*/
47 /**@brief Dirty flag*/
50 /**@brief Logical block ID*/
56 /**@brief Data buffer.*/
60 /**@brief Block cache descriptor*/
63 /**@brief Item count in block cache*/
66 /**@brief Item size in block cache*/
69 /**@brief Last recently used counter*/
72 /**@brief Reference count table*/
73 uint32_t refctr[CONFIG_BLOCK_DEV_CACHE_SIZE];
75 /**@brief Last recently used ID table*/
76 uint32_t lru_id[CONFIG_BLOCK_DEV_CACHE_SIZE];
78 /**@brief Writeback free delay mode table*/
79 uint8_t free_delay[CONFIG_BLOCK_DEV_CACHE_SIZE];
81 /**@brief Logical block table*/
82 uint64_t lba[CONFIG_BLOCK_DEV_CACHE_SIZE];
84 /**@brief Dirty mark*/
85 bool dirty[CONFIG_BLOCK_DEV_CACHE_SIZE];
87 /**@brief Cache data buffers*/
90 /**@brief Currently referenced datablocks*/
93 /**@brief Maximum referenced datablocks*/
94 uint32_t max_ref_blocks;
97 /**@brief Static initializer of block cache structure.*/
98 #define EXT4_BCACHE_STATIC_INSTANCE(__name, __cnt, __itemsize) \
99 static uint8_t __name##_data[(__cnt) * (__itemsize)]; \
100 static struct ext4_bcache __name = { \
102 .itemsize = __itemsize, \
104 .data = __name##_data, \
107 /**@brief Dynamic initialization of block cache.
108 * @param bc block cache descriptor
109 * @param cnt items count in block cache
110 * @param itemsize single item size (in bytes)
111 * @return standard error code*/
112 int ext4_bcache_init_dynamic(struct ext4_bcache *bc, uint32_t cnt,
115 /**@brief Dynamic de-initialization of block cache.
116 * @param bc block cache descriptor
117 * @return standard error code*/
118 int ext4_bcache_fini_dynamic(struct ext4_bcache *bc);
120 /**@brief Allocate block from block cache memory.
121 * Unreferenced block allocation is based on LRU
122 * (Last Recently Used) algorithm.
123 * @param bc block cache descriptor
124 * @param b block to alloc
125 * @param is_new block is new (needs to be read)
126 * @return standard error code*/
127 int ext4_bcache_alloc(struct ext4_bcache *bc, struct ext4_block *b,
130 /**@brief Free block from cache memory (decrement reference counter).
131 * @param bc block cache descriptor
132 * @param b block to free
133 * @param cache writeback mode
134 * @return standard error code*/
135 int ext4_bcache_free(struct ext4_bcache *bc, struct ext4_block *b,
138 /**@brief Return a full status of block cache.
139 * @param bc block cache descriptor
140 * @return full status*/
141 bool ext4_bcache_is_full(struct ext4_bcache *bc);
143 #endif /* EXT4_BCACHE_H_ */