1 | /* |
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2 | * fat_fat_operations.c |
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3 | * |
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4 | * General operations on File Allocation Table |
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5 | * |
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6 | * Copyright (C) 2001 OKTET Ltd., St.-Petersburg, Russia |
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7 | * Author: Eugeny S. Mints <Eugeny.Mints@oktet.ru> |
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8 | * |
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9 | * @(#) $Id$ |
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10 | */ |
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11 | |
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12 | #include <sys/types.h> |
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13 | #include <sys/stat.h> |
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14 | #include <fcntl.h> |
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15 | #include <unistd.h> |
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16 | #include <errno.h> |
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17 | #include <stdlib.h> |
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18 | #include <assert.h> |
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19 | |
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20 | #include <rtems/libio_.h> |
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21 | |
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22 | #include "fat.h" |
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23 | #include "fat_fat_operations.h" |
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24 | |
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25 | /* fat_scan_fat_for_free_clusters -- |
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26 | * Allocate chain of free clusters from Files Allocation Table |
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27 | * |
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28 | * PARAMETERS: |
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29 | * mt_entry - mount table entry |
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30 | * chain - the number of the first allocated cluster (first cluster |
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31 | * in the chain) |
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32 | * count - count of clusters to allocate (chain length) |
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33 | * |
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34 | * RETURNS: |
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35 | * RC_OK on success, or error code if error occured (errno set |
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36 | * appropriately) |
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37 | * |
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38 | * |
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39 | */ |
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40 | int |
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41 | fat_scan_fat_for_free_clusters( |
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42 | rtems_filesystem_mount_table_entry_t *mt_entry, |
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43 | unsigned32 *chain, |
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44 | unsigned32 count, |
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45 | unsigned32 *cls_added, |
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46 | unsigned32 *last_cl |
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47 | ) |
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48 | { |
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49 | int rc = RC_OK; |
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50 | fat_fs_info_t *fs_info = mt_entry->fs_info; |
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51 | unsigned32 cl4find = 2; |
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52 | unsigned32 next_cln = 0; |
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53 | unsigned32 save_cln = 0; |
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54 | unsigned32 data_cls_val = fs_info->vol.data_cls + 2; |
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55 | unsigned32 i = 2; |
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56 | |
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57 | *cls_added = 0; |
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58 | |
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59 | if (count == 0) |
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60 | return rc; |
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61 | |
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62 | if ((fs_info->vol.type & FAT_FAT32) && |
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63 | (fs_info->vol.next_cl != FAT_UNDEFINED_VALUE)) |
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64 | cl4find = fs_info->vol.next_cl; |
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65 | |
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66 | /* |
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67 | * fs_info->vol.data_cls is exactly the count of data clusters |
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68 | * starting at cluster 2, so the maximum valid cluster number is |
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69 | * (fs_info->vol.data_cls + 1) |
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70 | */ |
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71 | while (i < data_cls_val) |
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72 | { |
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73 | rc = fat_get_fat_cluster(mt_entry, cl4find, &next_cln); |
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74 | if ( rc != RC_OK ) |
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75 | { |
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76 | if (*cls_added != 0) |
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77 | fat_free_fat_clusters_chain(mt_entry, (*chain)); |
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78 | return rc; |
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79 | } |
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80 | |
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81 | if ((next_cln & fs_info->vol.mask) == FAT_GENFAT_FREE) |
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82 | { |
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83 | /* |
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84 | * We are enforced to process allocation of the first free cluster |
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85 | * by separate 'if' statement because otherwise undo function |
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86 | * wouldn't work properly |
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87 | */ |
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88 | if (*cls_added == 0) |
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89 | { |
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90 | *chain = cl4find; |
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91 | rc = fat_set_fat_cluster(mt_entry, cl4find, FAT_GENFAT_EOC); |
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92 | if ( rc != RC_OK ) |
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93 | { |
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94 | /* |
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95 | * this is the first cluster we tried to allocate so no |
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96 | * cleanup activity needed |
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97 | */ |
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98 | return rc; |
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99 | } |
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100 | } |
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101 | else |
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102 | { |
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103 | /* set EOC value to new allocated cluster */ |
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104 | rc = fat_set_fat_cluster(mt_entry, cl4find, FAT_GENFAT_EOC); |
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105 | if ( rc != RC_OK ) |
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106 | { |
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107 | /* cleanup activity */ |
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108 | fat_free_fat_clusters_chain(mt_entry, (*chain)); |
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109 | return rc; |
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110 | } |
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111 | |
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112 | rc = fat_set_fat_cluster(mt_entry, save_cln, cl4find); |
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113 | if ( rc != RC_OK ) |
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114 | { |
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115 | /* cleanup activity */ |
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116 | fat_free_fat_clusters_chain(mt_entry, (*chain)); |
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117 | /* trying to save last allocated cluster for future use */ |
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118 | fat_set_fat_cluster(mt_entry, cl4find, FAT_GENFAT_FREE); |
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119 | fat_buf_release(fs_info); |
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120 | return rc; |
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121 | } |
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122 | } |
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123 | |
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124 | save_cln = cl4find; |
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125 | (*cls_added)++; |
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126 | |
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127 | /* have we satisfied request ? */ |
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128 | if (*cls_added == count) |
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129 | { |
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130 | if (fs_info->vol.type & FAT_FAT32) |
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131 | { |
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132 | fs_info->vol.next_cl = save_cln; |
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133 | if (fs_info->vol.free_cls != 0xFFFFFFFF) |
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134 | fs_info->vol.free_cls -= (*cls_added); |
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135 | } |
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136 | *last_cl = save_cln; |
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137 | fat_buf_release(fs_info); |
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138 | return rc; |
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139 | } |
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140 | } |
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141 | i++; |
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142 | cl4find++; |
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143 | if (cl4find >= data_cls_val) |
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144 | cl4find = 2; |
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145 | } |
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146 | |
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147 | if (fs_info->vol.type & FAT_FAT32) |
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148 | { |
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149 | fs_info->vol.next_cl = save_cln; |
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150 | if (fs_info->vol.free_cls != 0xFFFFFFFF) |
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151 | fs_info->vol.free_cls -= (*cls_added); |
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152 | } |
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153 | *last_cl = save_cln; |
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154 | fat_buf_release(fs_info); |
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155 | return RC_OK; |
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156 | } |
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157 | |
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158 | /* fat_free_fat_clusters_chain -- |
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159 | * Free chain of clusters in Files Allocation Table. |
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160 | * |
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161 | * PARAMETERS: |
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162 | * mt_entry - mount table entry |
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163 | * chain - number of the first cluster in the chain |
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164 | * |
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165 | * RETURNS: |
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166 | * RC_OK on success, or -1 if error occured (errno set appropriately) |
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167 | */ |
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168 | int |
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169 | fat_free_fat_clusters_chain( |
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170 | rtems_filesystem_mount_table_entry_t *mt_entry, |
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171 | unsigned32 chain |
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172 | ) |
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173 | { |
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174 | int rc = RC_OK, rc1 = RC_OK; |
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175 | fat_fs_info_t *fs_info = mt_entry->fs_info; |
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176 | unsigned32 cur_cln = chain; |
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177 | unsigned32 next_cln = 0; |
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178 | unsigned32 freed_cls_cnt = 0; |
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179 | |
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180 | while ((cur_cln & fs_info->vol.mask) != fs_info->vol.eoc_val) |
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181 | { |
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182 | rc = fat_get_fat_cluster(mt_entry, cur_cln, &next_cln); |
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183 | if ( rc != RC_OK ) |
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184 | { |
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185 | if ((fs_info->vol.type & FAT_FAT32) && |
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186 | (fs_info->vol.free_cls != FAT_UNDEFINED_VALUE)) |
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187 | fs_info->vol.free_cls += freed_cls_cnt; |
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188 | fat_buf_release(fs_info); |
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189 | return rc; |
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190 | } |
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191 | |
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192 | rc = fat_set_fat_cluster(mt_entry, cur_cln, FAT_GENFAT_FREE); |
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193 | if ( rc != RC_OK ) |
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194 | rc1 = rc; |
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195 | |
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196 | freed_cls_cnt++; |
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197 | cur_cln = next_cln; |
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198 | } |
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199 | |
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200 | if (fs_info->vol.type & FAT_FAT32) |
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201 | { |
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202 | fs_info->vol.next_cl = chain; |
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203 | if (fs_info->vol.free_cls != FAT_UNDEFINED_VALUE) |
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204 | fs_info->vol.free_cls += freed_cls_cnt; |
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205 | } |
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206 | |
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207 | fat_buf_release(fs_info); |
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208 | if (rc1 != RC_OK) |
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209 | return rc1; |
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210 | |
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211 | return RC_OK; |
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212 | } |
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213 | |
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214 | /* fat_get_fat_cluster -- |
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215 | * Fetches the contents of the cluster (link to next cluster in the chain) |
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216 | * from Files Allocation Table. |
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217 | * |
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218 | * PARAMETERS: |
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219 | * mt_entry - mount table entry |
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220 | * cln - number of cluster to fetch the contents from |
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221 | * ret_val - contents of the cluster 'cln' (link to next cluster in |
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222 | * the chain) |
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223 | * |
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224 | * RETURNS: |
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225 | * RC_OK on success, or -1 if error occured |
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226 | * and errno set appropriately |
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227 | */ |
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228 | int |
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229 | fat_get_fat_cluster( |
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230 | rtems_filesystem_mount_table_entry_t *mt_entry, |
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231 | unsigned32 cln, |
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232 | unsigned32 *ret_val |
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233 | ) |
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234 | { |
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235 | int rc = RC_OK; |
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236 | register fat_fs_info_t *fs_info = mt_entry->fs_info; |
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237 | bdbuf_buffer *block0 = NULL; |
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238 | unsigned32 sec = 0; |
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239 | unsigned32 ofs = 0; |
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240 | |
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241 | /* sanity check */ |
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242 | if ( (cln < 2) || (cln > (fs_info->vol.data_cls + 1)) ) |
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243 | set_errno_and_return_minus_one(EIO); |
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244 | |
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245 | sec = (FAT_FAT_OFFSET(fs_info->vol.type, cln) >> fs_info->vol.sec_log2) + |
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246 | fs_info->vol.afat_loc; |
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247 | ofs = FAT_FAT_OFFSET(fs_info->vol.type, cln) & (fs_info->vol.bps - 1); |
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248 | |
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249 | rc = fat_buf_access(fs_info, sec, FAT_OP_TYPE_READ, &block0); |
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250 | if (rc != RC_OK) |
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251 | return rc; |
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252 | |
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253 | switch ( fs_info->vol.type ) |
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254 | { |
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255 | case FAT_FAT12: |
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256 | /* |
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257 | * we are enforced in complex computations for FAT12 to escape CPU |
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258 | * align problems for some architectures |
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259 | */ |
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260 | *ret_val = (*((unsigned8 *)(block0->buffer + ofs))); |
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261 | if ( ofs == (fs_info->vol.bps - 1) ) |
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262 | { |
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263 | rc = fat_buf_access(fs_info, sec + 1, FAT_OP_TYPE_READ, |
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264 | &block0); |
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265 | if (rc != RC_OK) |
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266 | return rc; |
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267 | |
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268 | *ret_val |= (*((unsigned8 *)(block0->buffer)))<<8; |
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269 | } |
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270 | else |
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271 | { |
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272 | *ret_val |= (*((unsigned8 *)(block0->buffer + ofs + 1)))<<8; |
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273 | } |
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274 | |
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275 | if ( FAT_CLUSTER_IS_ODD(cln) ) |
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276 | *ret_val = (*ret_val) >> FAT12_SHIFT; |
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277 | else |
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278 | *ret_val = (*ret_val) & FAT_FAT12_MASK; |
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279 | |
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280 | break; |
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281 | |
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282 | case FAT_FAT16: |
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283 | *ret_val = *((unsigned16 *)(block0->buffer + ofs)); |
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284 | *ret_val = CF_LE_W(*ret_val); |
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285 | break; |
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286 | |
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287 | case FAT_FAT32: |
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288 | *ret_val = *((unsigned32 *)(block0->buffer + ofs)); |
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289 | *ret_val = CF_LE_L(*ret_val); |
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290 | break; |
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291 | |
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292 | default: |
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293 | set_errno_and_return_minus_one(EIO); |
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294 | break; |
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295 | } |
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296 | |
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297 | return RC_OK; |
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298 | } |
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299 | |
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300 | /* fat_set_fat_cluster -- |
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301 | * Set the contents of the cluster (link to next cluster in the chain) |
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302 | * from Files Allocation Table. |
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303 | * |
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304 | * PARAMETERS: |
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305 | * mt_entry - mount table entry |
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306 | * cln - number of cluster to set contents to |
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307 | * in_val - value to set |
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308 | * |
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309 | * RETURNS: |
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310 | * RC_OK on success, or -1 if error occured |
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311 | * and errno set appropriately |
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312 | */ |
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313 | int |
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314 | fat_set_fat_cluster( |
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315 | rtems_filesystem_mount_table_entry_t *mt_entry, |
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316 | unsigned32 cln, |
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317 | unsigned32 in_val |
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318 | ) |
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319 | { |
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320 | int rc = RC_OK; |
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321 | fat_fs_info_t *fs_info = mt_entry->fs_info; |
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322 | unsigned32 sec = 0; |
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323 | unsigned32 ofs = 0; |
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324 | unsigned16 fat16_clv = 0; |
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325 | unsigned32 fat32_clv = 0; |
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326 | bdbuf_buffer *block0 = NULL; |
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327 | |
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328 | /* sanity check */ |
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329 | if ( (cln < 2) || (cln > (fs_info->vol.data_cls + 1)) ) |
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330 | set_errno_and_return_minus_one(EIO); |
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331 | |
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332 | sec = (FAT_FAT_OFFSET(fs_info->vol.type, cln) >> fs_info->vol.sec_log2) + |
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333 | fs_info->vol.afat_loc; |
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334 | ofs = FAT_FAT_OFFSET(fs_info->vol.type, cln) & (fs_info->vol.bps - 1); |
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335 | |
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336 | rc = fat_buf_access(fs_info, sec, FAT_OP_TYPE_READ, &block0); |
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337 | if (rc != RC_OK) |
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338 | return rc; |
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339 | |
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340 | switch ( fs_info->vol.type ) |
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341 | { |
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342 | case FAT_FAT12: |
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343 | if ( FAT_CLUSTER_IS_ODD(cln) ) |
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344 | { |
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345 | fat16_clv = CT_LE_W((((unsigned16)in_val) << FAT_FAT12_SHIFT)); |
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346 | |
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347 | *((unsigned8 *)(block0->buffer + ofs)) = |
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348 | (*((unsigned8 *)(block0->buffer + ofs))) & 0x0F; |
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349 | |
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350 | *((unsigned8 *)(block0->buffer + ofs)) = |
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351 | (*((unsigned8 *)(block0->buffer + ofs))) | |
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352 | (unsigned8)(fat16_clv & 0x00FF); |
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353 | |
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354 | fat_buf_mark_modified(fs_info); |
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355 | |
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356 | if ( ofs == (fs_info->vol.bps - 1) ) |
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357 | { |
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358 | rc = fat_buf_access(fs_info, sec + 1, FAT_OP_TYPE_READ, |
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359 | &block0); |
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360 | if (rc != RC_OK) |
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361 | return rc; |
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362 | |
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363 | *((unsigned8 *)(block0->buffer)) &= 0x00; |
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364 | |
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365 | *((unsigned8 *)(block0->buffer)) = |
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366 | (*((unsigned8 *)(block0->buffer))) | |
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367 | (unsigned8)((fat16_clv & 0xFF00)>>8); |
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368 | |
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369 | fat_buf_mark_modified(fs_info); |
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370 | } |
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371 | else |
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372 | { |
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373 | *((unsigned8 *)(block0->buffer + ofs + 1)) &= 0x00; |
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374 | |
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375 | *((unsigned8 *)(block0->buffer + ofs + 1)) = |
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376 | (*((unsigned8 *)(block0->buffer + ofs + 1))) | |
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377 | (unsigned8)((fat16_clv & 0xFF00)>>8); |
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378 | } |
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379 | } |
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380 | else |
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381 | { |
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382 | fat16_clv = CT_LE_W((((unsigned16)in_val) & FAT_FAT12_MASK)); |
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383 | |
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384 | *((unsigned8 *)(block0->buffer + ofs)) &= 0x00; |
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385 | |
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386 | *((unsigned8 *)(block0->buffer + ofs)) = |
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387 | (*((unsigned8 *)(block0->buffer + ofs))) | |
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388 | (unsigned8)(fat16_clv & 0x00FF); |
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389 | |
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390 | fat_buf_mark_modified(fs_info); |
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391 | |
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392 | if ( ofs == (fs_info->vol.bps - 1) ) |
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393 | { |
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394 | rc = fat_buf_access(fs_info, sec + 1, FAT_OP_TYPE_READ, |
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395 | &block0); |
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396 | if (rc != RC_OK) |
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397 | return rc; |
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398 | |
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399 | *((unsigned8 *)(block0->buffer)) = |
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400 | (*((unsigned8 *)(block0->buffer))) & 0xF0; |
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401 | |
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402 | *((unsigned8 *)(block0->buffer)) = |
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403 | (*((unsigned8 *)(block0->buffer))) | |
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404 | (unsigned8)((fat16_clv & 0xFF00)>>8); |
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405 | |
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406 | fat_buf_mark_modified(fs_info); |
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407 | } |
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408 | else |
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409 | { |
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410 | *((unsigned8 *)(block0->buffer + ofs + 1)) = |
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411 | (*((unsigned8 *)(block0->buffer + ofs + 1))) & 0xF0; |
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412 | |
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413 | *((unsigned8 *)(block0->buffer + ofs+1)) = |
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414 | (*((unsigned8 *)(block0->buffer + ofs+1))) | |
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415 | (unsigned8)((fat16_clv & 0xFF00)>>8); |
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416 | } |
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417 | } |
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418 | break; |
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419 | |
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420 | case FAT_FAT16: |
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421 | *((unsigned16 *)(block0->buffer + ofs)) = |
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422 | (unsigned16)(CT_LE_W(in_val)); |
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423 | fat_buf_mark_modified(fs_info); |
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424 | break; |
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425 | |
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426 | case FAT_FAT32: |
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427 | fat32_clv = CT_LE_L((in_val & FAT_FAT32_MASK)); |
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428 | |
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429 | *((unsigned32 *)(block0->buffer + ofs)) = |
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430 | (*((unsigned32 *)(block0->buffer + ofs))) & (CT_LE_L(0xF0000000)); |
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431 | |
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432 | *((unsigned32 *)(block0->buffer + ofs)) = |
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433 | fat32_clv | (*((unsigned32 *)(block0->buffer + ofs))); |
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434 | |
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435 | fat_buf_mark_modified(fs_info); |
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436 | break; |
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437 | |
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438 | default: |
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439 | set_errno_and_return_minus_one(EIO); |
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440 | break; |
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441 | |
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442 | } |
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443 | |
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444 | return RC_OK; |
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445 | } |
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