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