1 | /*
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2 | * Copyright (c) 2011 Martin Sucha
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3 | * All rights reserved.
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4 | *
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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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7 | * are met:
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8 | *
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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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16 | *
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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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27 | */
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28 |
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29 | /** @addtogroup libext2
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30 | * @{
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31 | */
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32 | /**
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33 | * @file
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34 | */
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35 |
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36 | #include "libext2_filesystem.h"
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37 | #include "libext2_superblock.h"
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38 | #include "libext2_block_group.h"
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39 | #include <errno.h>
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40 | #include <libblock.h>
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41 | #include <malloc.h>
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42 |
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43 | /**
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44 | * Initialize an instance of filesystem on the device.
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45 | * This function reads superblock from the device and
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46 | * initializes libblock cache with appropriate logical block size.
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47 | *
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48 | * @param fs Pointer to ext2_filesystem_t to initialize
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49 | * @param devmap_handle Device handle of the block device
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50 | *
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51 | * @return EOK on success or negative error code on failure
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52 | */
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53 | int ext2_filesystem_init(ext2_filesystem_t *fs, devmap_handle_t devmap_handle)
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54 | {
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55 | int rc;
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56 | ext2_superblock_t *temp_superblock;
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57 | size_t block_size;
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58 |
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59 | fs->device = devmap_handle;
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60 |
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61 | rc = block_init(fs->device, 2048);
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62 | if (rc != EOK) {
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63 | return rc;
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64 | }
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65 |
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66 | rc = ext2_superblock_read_direct(fs->device, &temp_superblock);
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67 | if (rc != EOK) {
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68 | block_fini(fs->device);
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69 | return rc;
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70 | }
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71 |
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72 | block_size = ext2_superblock_get_block_size(temp_superblock);
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73 |
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74 | if (block_size > EXT2_MAX_BLOCK_SIZE) {
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75 | block_fini(fs->device);
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76 | return ENOTSUP;
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77 | }
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78 |
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79 | rc = block_cache_init(devmap_handle, block_size, 0, CACHE_MODE_WT);
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80 | if (rc != EOK) {
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81 | block_fini(fs->device);
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82 | return rc;
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83 | }
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84 |
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85 | fs->superblock = temp_superblock;
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86 |
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87 | return EOK;
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88 | }
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89 |
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90 | /**
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91 | * Check filesystem for sanity
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92 | *
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93 | * @param fs Pointer to ext2_filesystem_t to check
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94 | * @return EOK on success or negative error code on failure
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95 | */
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96 | int ext2_filesystem_check_sanity(ext2_filesystem_t *fs)
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97 | {
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98 | int rc;
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99 |
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100 | rc = ext2_superblock_check_sanity(fs->superblock);
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101 | if (rc != EOK) {
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102 | return rc;
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103 | }
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104 |
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105 | return EOK;
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106 | }
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107 |
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108 | /**
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109 | * Get a reference to block descriptor
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110 | *
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111 | * @param fs Pointer to filesystem information
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112 | * @param bgid Index of block group to find
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113 | * @param ref Pointer where to store pointer to block group reference
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114 | *
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115 | * @return EOK on success or negative error code on failure
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116 | */
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117 | int ext2_filesystem_get_block_group_ref(ext2_filesystem_t *fs, uint32_t bgid,
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118 | ext2_block_group_ref_t **ref)
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119 | {
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120 | int rc;
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121 | aoff64_t block_id;
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122 | uint32_t descriptors_per_block;
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123 | size_t offset;
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124 | ext2_block_group_ref_t *newref;
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125 |
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126 | newref = malloc(sizeof(ext2_block_group_ref_t));
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127 | if (newref == NULL) {
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128 | return ENOMEM;
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129 | }
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130 |
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131 | descriptors_per_block = ext2_superblock_get_block_size(fs->superblock)
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132 | / EXT2_BLOCK_GROUP_DESCRIPTOR_SIZE;
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133 |
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134 | // Block group descriptor table starts at the next block after superblock
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135 | block_id = ext2_superblock_get_first_block(fs->superblock) + 1;
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136 |
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137 | // Find the block containing the descriptor we are looking for
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138 | block_id += bgid / descriptors_per_block;
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139 | offset = (bgid % descriptors_per_block) * EXT2_BLOCK_GROUP_DESCRIPTOR_SIZE;
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140 |
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141 | rc = block_get(&newref->block, fs->device, block_id, 0);
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142 | if (rc != EOK) {
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143 | free(newref);
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144 | return rc;
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145 | }
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146 |
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147 | newref->block_group = newref->block->data + offset;
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148 |
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149 | *ref = newref;
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150 |
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151 | return EOK;
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152 | }
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153 |
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154 | /**
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155 | * Free a reference to block group
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156 | *
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157 | * @param ref Pointer to block group reference to free
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158 | *
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159 | * @return EOK on success or negative error code on failure
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160 | */
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161 | int ext2_filesystem_put_block_group_ref(ext2_block_group_ref_t *ref)
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162 | {
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163 | int rc;
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164 |
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165 | rc = block_put(ref->block);
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166 | free(ref);
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167 |
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168 | return rc;
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169 | }
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170 |
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171 | /**
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172 | * Finalize an instance of filesystem
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173 | *
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174 | * @param fs Pointer to ext2_filesystem_t to finalize
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175 | */
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176 | void ext2_filesystem_fini(ext2_filesystem_t *fs)
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177 | {
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178 | free(fs->superblock);
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179 | block_fini(fs->device);
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180 | }
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181 |
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182 |
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183 | /** @}
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184 | */
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