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 #define EXT4_BLOCK_ZERO() \
46 {.uptodate = 0, .dirty = 0, .lb_id = 0, .cache_id = 0, .data = 0}
48 /**@brief Single block descriptor*/
50 /**@brief Uptodate flag*/
53 /**@brief Dirty flag*/
56 /**@brief Logical block ID*/
62 /**@brief Data buffer.*/
66 /**@brief Block cache descriptor*/
69 /**@brief Item count in block cache*/
72 /**@brief Item size in block cache*/
75 /**@brief Last recently used counter*/
78 /**@brief Reference count table*/
79 uint32_t refctr[CONFIG_BLOCK_DEV_CACHE_SIZE];
81 /**@brief Last recently used ID table*/
82 uint32_t lru_id[CONFIG_BLOCK_DEV_CACHE_SIZE];
84 /**@brief Writeback free delay mode table*/
85 uint8_t free_delay[CONFIG_BLOCK_DEV_CACHE_SIZE];
87 /**@brief Logical block table*/
88 uint64_t lba[CONFIG_BLOCK_DEV_CACHE_SIZE];
91 int flags[CONFIG_BLOCK_DEV_CACHE_SIZE];
93 /**@brief Cache data buffers*/
96 /**@brief Currently referenced datablocks*/
99 /**@brief Maximum referenced datablocks*/
100 uint32_t max_ref_blocks;
103 enum bcache_state_bits {
108 #define ext4_bcache_set_flag(bc, id, b) \
109 (bc)->flags[id] |= 1 << (b)
111 #define ext4_bcache_clear_flag(bc, id, b) \
112 (bc)->flags[id] &= ~(1 << (b))
114 #define ext4_bcache_test_flag(bc, id, b) \
115 (((bc)->flags[id] & (1 << (b))) >> (b))
117 /**@brief Static initializer of block cache structure.*/
118 #define EXT4_BCACHE_STATIC_INSTANCE(__name, __cnt, __itemsize) \
119 static uint8_t __name##_data[(__cnt) * (__itemsize)]; \
120 static struct ext4_bcache __name = { \
122 .itemsize = __itemsize, \
124 .data = __name##_data, \
127 /**@brief Dynamic initialization of block cache.
128 * @param bc block cache descriptor
129 * @param cnt items count in block cache
130 * @param itemsize single item size (in bytes)
131 * @return standard error code*/
132 int ext4_bcache_init_dynamic(struct ext4_bcache *bc, uint32_t cnt,
135 /**@brief Dynamic de-initialization of block cache.
136 * @param bc block cache descriptor
137 * @return standard error code*/
138 int ext4_bcache_fini_dynamic(struct ext4_bcache *bc);
140 /**@brief Allocate block from block cache memory.
141 * Unreferenced block allocation is based on LRU
142 * (Last Recently Used) algorithm.
143 * @param bc block cache descriptor
144 * @param b block to alloc
145 * @param is_new block is new (needs to be read)
146 * @return standard error code*/
147 int ext4_bcache_alloc(struct ext4_bcache *bc, struct ext4_block *b,
150 /**@brief Free block from cache memory (decrement reference counter).
151 * @param bc block cache descriptor
152 * @param b block to free
153 * @param cache writeback mode
154 * @return standard error code*/
155 int ext4_bcache_free(struct ext4_bcache *bc, struct ext4_block *b,
158 /**@brief Return a full status of block cache.
159 * @param bc block cache descriptor
160 * @return full status*/
161 bool ext4_bcache_is_full(struct ext4_bcache *bc);
163 #endif /* EXT4_BCACHE_H_ */