1 | /* |
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2 | * COPYRIGHT (c) 2010 Chris Johns <chrisj@rtems.org> |
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3 | * |
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4 | * The license and distribution terms for this file may be |
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5 | * found in the file LICENSE in this distribution or at |
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6 | * http://www.rtems.com/license/LICENSE. |
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7 | * |
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8 | * $Id$ |
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9 | */ |
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10 | /** |
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11 | * @file |
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12 | * |
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13 | * @ingroup rtems-rfs |
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14 | * |
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15 | * RTEMS File Systems Block Routines. |
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16 | * |
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17 | * These functions manage blocks in the RFS file system. A block is an area of |
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18 | * the media and its size is set for a each specific media. The block size is |
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19 | * set when the file system is set up and needs to be matched for it to be read |
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20 | * correctly. |
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21 | * |
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22 | * Blocks are managed as groups. A block group or "group" is part of the total |
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23 | * number of blocks being managed by the file system and exist to allow |
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24 | * resources to localised. A file in a directory will be allocated blocks in |
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25 | * the same group as the directory, and the blocks for the file will also be |
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26 | * allocated in the same group. |
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27 | * |
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28 | * A group consist of a block bitmap, inodes and data blocks. The first block |
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29 | * of the file system will hold the superblock. The block bitmap is a |
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30 | * collection of blocks that hold a map of bits, one bit per block for each |
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31 | * block in the group. When a file system is mounted the block bitmaps are read |
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32 | * and a summary bit map is made. The summary bitmap has a single bit for 32 |
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33 | * bits in the bitmap and is set when all 32 bits it maps to are set. This |
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34 | * speeds up the search for a free block by a factor of 32. |
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35 | */ |
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36 | |
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37 | #include <rtems/rfs/rtems-rfs-block.h> |
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38 | #include <rtems/rfs/rtems-rfs-data.h> |
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39 | #include <rtems/rfs/rtems-rfs-group.h> |
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40 | #include <rtems/rfs/rtems-rfs-inode.h> |
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41 | |
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42 | void |
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43 | rtems_rfs_block_get_bpos (rtems_rfs_file_system* fs, |
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44 | rtems_rfs_pos pos, |
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45 | rtems_rfs_block_pos* bpos) |
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46 | { |
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47 | bpos->bno = pos / rtems_rfs_fs_block_size (fs); |
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48 | bpos->boff = pos % rtems_rfs_fs_block_size (fs); |
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49 | } |
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50 | |
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51 | rtems_rfs_pos |
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52 | rtems_rfs_block_get_pos (rtems_rfs_file_system* fs, |
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53 | rtems_rfs_block_pos* bpos) |
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54 | { |
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55 | rtems_rfs_pos pos = 0; |
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56 | if (bpos->bno) |
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57 | { |
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58 | pos = bpos->boff; |
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59 | if (pos == 0) |
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60 | pos = rtems_rfs_fs_block_size (fs); |
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61 | pos += (bpos->bno - 1) * rtems_rfs_fs_block_size (fs); |
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62 | } |
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63 | return pos; |
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64 | } |
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65 | |
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66 | void |
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67 | rtems_rfs_block_get_block_size (rtems_rfs_file_system* fs, |
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68 | rtems_rfs_pos pos, |
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69 | rtems_rfs_block_size* size) |
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70 | { |
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71 | if (pos == 0) |
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72 | rtems_rfs_block_set_size_zero (size); |
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73 | else |
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74 | { |
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75 | size->count = pos / rtems_rfs_fs_block_size (fs) + 1; |
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76 | size->offset = pos % rtems_rfs_fs_block_size (fs); |
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77 | } |
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78 | } |
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79 | |
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80 | rtems_rfs_pos |
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81 | rtems_rfs_block_get_size (rtems_rfs_file_system* fs, |
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82 | rtems_rfs_block_size* size) |
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83 | { |
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84 | uint32_t offset; |
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85 | if (size->count == 0) |
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86 | return 0; |
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87 | if (size->offset == 0) |
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88 | offset = rtems_rfs_fs_block_size (fs); |
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89 | else |
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90 | offset = size->offset; |
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91 | return (((uint64_t) (size->count - 1)) * rtems_rfs_fs_block_size (fs)) + offset; |
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92 | } |
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93 | |
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94 | int |
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95 | rtems_rfs_block_map_open (rtems_rfs_file_system* fs, |
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96 | rtems_rfs_inode_handle* inode, |
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97 | rtems_rfs_block_map* map) |
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98 | { |
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99 | int b; |
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100 | int rc; |
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101 | |
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102 | /* |
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103 | * Set the count to 0 so at least find fails, then open the handle and make |
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104 | * sure the inode has been loaded into memory. If we did not load the inode |
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105 | * do not unload it. The caller may assume it is still loaded when we return. |
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106 | */ |
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107 | |
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108 | map->dirty = false; |
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109 | map->inode = NULL; |
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110 | rtems_rfs_block_set_size_zero (&map->size); |
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111 | rtems_rfs_block_set_bpos_zero (&map->bpos); |
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112 | |
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113 | rc = rtems_rfs_buffer_handle_open (fs, &map->singly_buffer); |
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114 | if (rc > 0) |
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115 | return rc; |
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116 | rc = rtems_rfs_buffer_handle_open (fs, &map->doubly_buffer); |
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117 | if (rc > 0) |
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118 | return rc; |
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119 | |
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120 | rc = rtems_rfs_inode_load (fs, inode); |
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121 | if (rc > 0) |
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122 | { |
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123 | rtems_rfs_buffer_handle_close (fs, &map->singly_buffer); |
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124 | rtems_rfs_buffer_handle_close (fs, &map->doubly_buffer); |
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125 | return rc; |
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126 | } |
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127 | |
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128 | /* |
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129 | * Extract the block and block count data from the inode into the targets |
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130 | * byte order. |
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131 | */ |
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132 | map->inode = inode; |
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133 | for (b = 0; b < RTEMS_RFS_INODE_BLOCKS; b++) |
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134 | map->blocks[b] = rtems_rfs_inode_get_block (inode, b); |
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135 | map->size.count = rtems_rfs_inode_get_block_count (inode); |
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136 | map->size.offset = rtems_rfs_inode_get_block_offset (inode); |
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137 | map->last_map_block = rtems_rfs_inode_get_last_map_block (inode); |
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138 | map->last_data_block = rtems_rfs_inode_get_last_data_block (inode); |
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139 | |
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140 | rc = rtems_rfs_inode_unload (fs, inode, false); |
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141 | |
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142 | return rc; |
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143 | } |
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144 | |
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145 | int |
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146 | rtems_rfs_block_map_close (rtems_rfs_file_system* fs, |
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147 | rtems_rfs_block_map* map) |
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148 | { |
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149 | int rc = 0; |
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150 | int brc; |
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151 | |
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152 | if (map->dirty && map->inode) |
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153 | { |
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154 | brc = rtems_rfs_inode_load (fs, map->inode); |
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155 | if (brc > 0) |
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156 | rc = brc; |
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157 | |
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158 | if (rc == 0) |
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159 | { |
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160 | int b; |
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161 | |
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162 | for (b = 0; b < RTEMS_RFS_INODE_BLOCKS; b++) |
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163 | rtems_rfs_inode_set_block (map->inode, b, map->blocks[b]); |
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164 | rtems_rfs_inode_set_block_count (map->inode, map->size.count); |
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165 | rtems_rfs_inode_set_block_offset (map->inode, map->size.offset); |
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166 | rtems_rfs_inode_set_last_map_block (map->inode, map->last_map_block); |
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167 | rtems_rfs_inode_set_last_data_block (map->inode, map->last_data_block); |
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168 | |
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169 | brc = rtems_rfs_inode_unload (fs, map->inode, true); |
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170 | if (brc > 0) |
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171 | rc = brc; |
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172 | |
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173 | map->dirty = false; |
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174 | } |
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175 | } |
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176 | |
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177 | map->inode = NULL; |
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178 | |
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179 | brc = rtems_rfs_buffer_handle_close (fs, &map->singly_buffer); |
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180 | if ((brc > 0) && (rc == 0)) |
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181 | rc = brc; |
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182 | brc = rtems_rfs_buffer_handle_close (fs, &map->doubly_buffer); |
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183 | if ((brc > 0) && (rc == 0)) |
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184 | rc = brc; |
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185 | return rc; |
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186 | } |
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187 | |
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188 | /** |
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189 | * Find a block indirectly held in a table of block numbers. |
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190 | * |
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191 | * @param fs The file system. |
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192 | * @param buffer The handle to access the block data by. |
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193 | * @param block The block number of the table of block numbers. |
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194 | * @param offset The offset in the table of the block number to return. This is |
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195 | * a block number offset not a byte offset into the table. |
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196 | * @param result Pointer to the result of the search. |
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197 | * @return int The error number (errno). No error if 0. |
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198 | */ |
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199 | static int |
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200 | rtems_rfs_block_find_indirect (rtems_rfs_file_system* fs, |
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201 | rtems_rfs_buffer_handle* buffer, |
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202 | rtems_rfs_block_no block, |
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203 | int offset, |
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204 | rtems_rfs_block_no* result) |
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205 | { |
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206 | int rc; |
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207 | |
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208 | /* |
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209 | * If the handle has a buffer and this request is a different block the current |
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210 | * buffer is released. |
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211 | */ |
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212 | rc = rtems_rfs_buffer_handle_request (fs, buffer, block, true); |
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213 | if (rc > 0) |
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214 | return rc; |
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215 | |
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216 | *result = rtems_rfs_block_get_number (buffer, offset); |
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217 | if ((*result + 1) == 0) |
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218 | *result = 0; |
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219 | |
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220 | if (*result >= rtems_rfs_fs_blocks (fs)) |
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221 | { |
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222 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BLOCK_FIND)) |
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223 | printf ("rtems-rfs: block-find: invalid block in table:" \ |
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224 | " block=%ld, indirect=%ld/%d\n", *result, block, offset); |
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225 | *result = 0; |
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226 | rc = EIO; |
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227 | } |
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228 | |
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229 | return 0; |
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230 | } |
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231 | |
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232 | int |
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233 | rtems_rfs_block_map_find (rtems_rfs_file_system* fs, |
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234 | rtems_rfs_block_map* map, |
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235 | rtems_rfs_block_pos* bpos, |
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236 | rtems_rfs_block_no* block) |
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237 | { |
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238 | int rc = 0; |
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239 | |
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240 | *block = 0; |
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241 | |
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242 | /* |
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243 | * Range checking here makes the remaining logic simpler. |
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244 | */ |
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245 | if (rtems_rfs_block_pos_block_past_end (bpos, &map->size)) |
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246 | return ENXIO; |
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247 | |
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248 | /* |
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249 | * If the block position is the same and we have found the block just return it. |
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250 | */ |
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251 | if ((bpos->bno == map->bpos.bno) && (map->bpos.block != 0)) |
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252 | { |
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253 | *block = map->bpos.block; |
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254 | } |
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255 | else |
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256 | { |
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257 | /* |
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258 | * Determine the type of access we need to perform. If the number of blocks |
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259 | * is less than or equal to the number of slots in the inode the blocks are |
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260 | * directly accessed. |
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261 | */ |
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262 | if (map->size.count <= RTEMS_RFS_INODE_BLOCKS) |
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263 | { |
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264 | *block = map->blocks[bpos->bno]; |
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265 | } |
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266 | else |
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267 | { |
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268 | /* |
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269 | * The map is either singly or doubly indirect. |
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270 | */ |
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271 | rtems_rfs_block_no direct; |
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272 | rtems_rfs_block_no singly; |
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273 | |
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274 | direct = bpos->bno % fs->blocks_per_block; |
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275 | singly = bpos->bno / fs->blocks_per_block; |
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276 | |
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277 | if (map->size.count <= fs->block_map_singly_blocks) |
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278 | { |
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279 | /* |
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280 | * This is a single indirect table of blocks anchored off a slot in the |
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281 | * inode. |
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282 | */ |
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283 | rc = rtems_rfs_block_find_indirect (fs, |
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284 | &map->singly_buffer, |
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285 | map->blocks[singly], |
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286 | direct, block); |
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287 | } |
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288 | else |
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289 | { |
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290 | /* |
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291 | * The map is doubly indirect. |
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292 | */ |
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293 | rtems_rfs_block_no doubly; |
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294 | |
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295 | doubly = singly / fs->blocks_per_block; |
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296 | singly %= fs->blocks_per_block; |
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297 | |
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298 | if (map->size.count < fs->block_map_doubly_blocks) |
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299 | { |
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300 | rc = rtems_rfs_block_find_indirect (fs, |
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301 | &map->doubly_buffer, |
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302 | map->blocks[doubly], |
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303 | singly, &singly); |
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304 | if (rc == 0) |
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305 | { |
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306 | rc = rtems_rfs_block_find_indirect (fs, |
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307 | &map->singly_buffer, |
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308 | singly, direct, block); |
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309 | } |
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310 | } |
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311 | else |
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312 | { |
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313 | /* |
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314 | * This should never happen. Here so Joel can remove once his coverage |
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315 | * testing gets to the file systems. |
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316 | */ |
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317 | rc = ENXIO; |
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318 | } |
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319 | } |
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320 | } |
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321 | } |
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322 | |
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323 | if (rc == 0) |
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324 | { |
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325 | rtems_rfs_block_copy_bpos (&map->bpos, bpos); |
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326 | map->bpos.block = *block; |
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327 | } |
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328 | |
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329 | return rc; |
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330 | } |
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331 | |
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332 | int |
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333 | rtems_rfs_block_map_seek (rtems_rfs_file_system* fs, |
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334 | rtems_rfs_block_map* map, |
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335 | rtems_rfs_pos_rel offset, |
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336 | rtems_rfs_block_no* block) |
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337 | { |
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338 | rtems_rfs_block_pos bpos; |
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339 | rtems_rfs_block_copy_bpos (&bpos, &map->bpos); |
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340 | rtems_rfs_block_add_pos (fs, offset, &bpos); |
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341 | return rtems_rfs_block_map_find (fs, map, &bpos, block); |
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342 | } |
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343 | |
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344 | int |
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345 | rtems_rfs_block_map_next_block (rtems_rfs_file_system* fs, |
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346 | rtems_rfs_block_map* map, |
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347 | rtems_rfs_block_no* block) |
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348 | { |
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349 | rtems_rfs_block_pos bpos; |
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350 | bpos.bno = map->bpos.bno + 1; |
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351 | bpos.boff = 0; |
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352 | bpos.block = 0; |
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353 | return rtems_rfs_block_map_find (fs, map, &bpos, block); |
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354 | } |
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355 | |
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356 | /** |
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357 | * Allocate an indirect block to a map. |
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358 | * |
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359 | * @param fs The file system data. |
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360 | * @param map The map the allocation is for. |
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361 | * @param buffer The buffer the indirect block is accessed by. |
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362 | * @param block The block number of the indirect block allocated. |
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363 | * @param upping True is upping the map to the next indirect level. |
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364 | * @return int The error number (errno). No error if 0. |
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365 | */ |
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366 | static int |
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367 | rtems_rfs_block_map_indirect_alloc (rtems_rfs_file_system* fs, |
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368 | rtems_rfs_block_map* map, |
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369 | rtems_rfs_buffer_handle* buffer, |
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370 | rtems_rfs_block_no* block, |
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371 | bool upping) |
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372 | { |
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373 | rtems_rfs_bitmap_bit new_block; |
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374 | int rc; |
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375 | /* |
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376 | * Save the new block locally because upping can have *block pointing to the |
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377 | * slots which are cleared when upping. |
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378 | */ |
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379 | rc = rtems_rfs_group_bitmap_alloc (fs, map->last_map_block, false, &new_block); |
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380 | if (rc > 0) |
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381 | return rc; |
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382 | rc = rtems_rfs_buffer_handle_request (fs, buffer, new_block, false); |
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383 | if (rc > 0) |
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384 | { |
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385 | rtems_rfs_group_bitmap_free (fs, false, new_block); |
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386 | return rc; |
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387 | } |
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388 | memset (rtems_rfs_buffer_data (buffer), 0xff, rtems_rfs_fs_block_size (fs)); |
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389 | if (upping) |
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390 | { |
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391 | int b; |
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392 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BLOCK_MAP_GROW)) |
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393 | printf ("rtems-rfs: block-map-grow: upping: block-count=%ld\n", |
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394 | map->size.count); |
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395 | for (b = 0; b < RTEMS_RFS_INODE_BLOCKS; b++) |
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396 | rtems_rfs_block_set_number (buffer, b, map->blocks[b]); |
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397 | memset (map->blocks, 0, sizeof (map->blocks)); |
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398 | } |
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399 | rtems_rfs_buffer_mark_dirty (buffer); |
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400 | *block = new_block; |
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401 | map->last_map_block = new_block; |
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402 | return 0; |
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403 | } |
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404 | |
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405 | int |
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406 | rtems_rfs_block_map_grow (rtems_rfs_file_system* fs, |
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407 | rtems_rfs_block_map* map, |
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408 | size_t blocks, |
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409 | rtems_rfs_block_no* new_block) |
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410 | { |
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411 | int b; |
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412 | |
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413 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BLOCK_MAP_GROW)) |
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414 | printf ("rtems-rfs: block-map-grow: entry: blocks=%ld count=%lu\n", |
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415 | blocks, map->size.count); |
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416 | |
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417 | if ((map->size.count + blocks) >= rtems_rfs_fs_max_block_map_blocks (fs)) |
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418 | return EFBIG; |
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419 | |
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420 | /* |
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421 | * Allocate a block at a time. The buffer handles hold the blocks so adding |
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422 | * this way does not thrash the cache with lots of requests. |
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423 | */ |
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424 | for (b = 0; b < blocks; b++) |
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425 | { |
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426 | rtems_rfs_bitmap_bit block; |
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427 | int rc; |
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428 | |
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429 | /* |
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430 | * Allocate the block. If an indirect block is needed and cannot be |
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431 | * allocated free this block. |
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432 | */ |
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433 | |
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434 | rc = rtems_rfs_group_bitmap_alloc (fs, map->last_data_block, |
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435 | false, &block); |
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436 | if (rc > 0) |
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437 | return rc; |
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438 | |
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439 | if (map->size.count < RTEMS_RFS_INODE_BLOCKS) |
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440 | map->blocks[map->size.count] = block; |
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441 | else |
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442 | { |
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443 | /* |
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444 | * Single indirect access is occuring. It could still be doubly indirect. |
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445 | */ |
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446 | rtems_rfs_block_no direct; |
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447 | rtems_rfs_block_no singly; |
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448 | |
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449 | direct = map->size.count % fs->blocks_per_block; |
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450 | singly = map->size.count / fs->blocks_per_block; |
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451 | |
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452 | if (map->size.count < fs->block_map_singly_blocks) |
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453 | { |
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454 | /* |
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455 | * Singly indirect tables are being used. Allocate a new block for a |
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456 | * mapping table if direct is 0 or we are moving up (upping). If upping |
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457 | * move the direct blocks into the table and if not this is the first |
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458 | * entry of a new block. |
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459 | */ |
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460 | if ((direct == 0) || |
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461 | ((singly == 0) && (direct == RTEMS_RFS_INODE_BLOCKS))) |
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462 | { |
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463 | /* |
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464 | * Upping is when we move from direct to singly indirect. |
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465 | */ |
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466 | bool upping; |
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467 | upping = map->size.count == RTEMS_RFS_INODE_BLOCKS; |
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468 | rc = rtems_rfs_block_map_indirect_alloc (fs, map, |
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469 | &map->singly_buffer, |
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470 | &map->blocks[singly], |
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471 | upping); |
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472 | } |
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473 | else |
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474 | { |
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475 | rc = rtems_rfs_buffer_handle_request (fs, &map->singly_buffer, |
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476 | map->blocks[singly], true); |
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477 | } |
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478 | |
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479 | if (rc > 0) |
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480 | { |
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481 | rtems_rfs_group_bitmap_free (fs, false, block); |
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482 | return rc; |
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483 | } |
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484 | } |
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485 | else |
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486 | { |
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487 | /* |
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488 | * Doubly indirect tables are being used. |
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489 | */ |
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490 | rtems_rfs_block_no doubly; |
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491 | rtems_rfs_block_no singly_block; |
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492 | |
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493 | doubly = singly / fs->blocks_per_block; |
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494 | singly %= fs->blocks_per_block; |
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495 | |
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496 | /* |
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497 | * Allocate a new block for a singly indirect table if direct is 0 as |
---|
498 | * it is the first entry of a new block. We may also need to allocate a |
---|
499 | * doubly indirect block as well. Both always occur when direct is 0 |
---|
500 | * and the doubly indirect block when singly is 0. |
---|
501 | */ |
---|
502 | if (direct == 0) |
---|
503 | { |
---|
504 | rc = rtems_rfs_block_map_indirect_alloc (fs, map, |
---|
505 | &map->singly_buffer, |
---|
506 | &singly_block, |
---|
507 | false); |
---|
508 | if (rc > 0) |
---|
509 | { |
---|
510 | rtems_rfs_group_bitmap_free (fs, false, block); |
---|
511 | return rc; |
---|
512 | } |
---|
513 | |
---|
514 | /* |
---|
515 | * Allocate a new block for a doubly indirect table if singly is 0 as |
---|
516 | * it is the first entry of a new singly indirect block. |
---|
517 | */ |
---|
518 | if ((singly == 0) || |
---|
519 | ((doubly == 0) && (singly == RTEMS_RFS_INODE_BLOCKS))) |
---|
520 | { |
---|
521 | bool upping; |
---|
522 | upping = map->size.count == fs->block_map_singly_blocks; |
---|
523 | rc = rtems_rfs_block_map_indirect_alloc (fs, map, |
---|
524 | &map->doubly_buffer, |
---|
525 | &map->blocks[doubly], |
---|
526 | upping); |
---|
527 | if (rc > 0) |
---|
528 | { |
---|
529 | rtems_rfs_group_bitmap_free (fs, false, singly_block); |
---|
530 | rtems_rfs_group_bitmap_free (fs, false, block); |
---|
531 | return rc; |
---|
532 | } |
---|
533 | } |
---|
534 | else |
---|
535 | { |
---|
536 | rc = rtems_rfs_buffer_handle_request (fs, &map->doubly_buffer, |
---|
537 | map->blocks[doubly], true); |
---|
538 | if (rc > 0) |
---|
539 | { |
---|
540 | rtems_rfs_group_bitmap_free (fs, false, singly_block); |
---|
541 | rtems_rfs_group_bitmap_free (fs, false, block); |
---|
542 | return rc; |
---|
543 | } |
---|
544 | } |
---|
545 | |
---|
546 | rtems_rfs_block_set_number (&map->doubly_buffer, |
---|
547 | singly, |
---|
548 | singly_block); |
---|
549 | } |
---|
550 | else |
---|
551 | { |
---|
552 | rc = rtems_rfs_buffer_handle_request (fs, |
---|
553 | &map->doubly_buffer, |
---|
554 | map->blocks[doubly], |
---|
555 | true); |
---|
556 | if (rc > 0) |
---|
557 | { |
---|
558 | rtems_rfs_group_bitmap_free (fs, false, block); |
---|
559 | return rc; |
---|
560 | } |
---|
561 | |
---|
562 | singly_block = rtems_rfs_block_get_number (&map->doubly_buffer, |
---|
563 | singly); |
---|
564 | |
---|
565 | rc = rtems_rfs_buffer_handle_request (fs, &map->singly_buffer, |
---|
566 | singly_block, true); |
---|
567 | if (rc > 0) |
---|
568 | { |
---|
569 | rtems_rfs_group_bitmap_free (fs, false, block); |
---|
570 | return rc; |
---|
571 | } |
---|
572 | } |
---|
573 | } |
---|
574 | |
---|
575 | rtems_rfs_block_set_number (&map->singly_buffer, direct, block); |
---|
576 | } |
---|
577 | |
---|
578 | map->size.count++; |
---|
579 | map->size.offset = 0; |
---|
580 | |
---|
581 | if (b == 0) |
---|
582 | *new_block = block; |
---|
583 | map->last_data_block = block; |
---|
584 | map->dirty = true; |
---|
585 | } |
---|
586 | |
---|
587 | return 0; |
---|
588 | } |
---|
589 | |
---|
590 | /** |
---|
591 | * Shrink an indirect block. |
---|
592 | * |
---|
593 | * @param fs The file system data. |
---|
594 | * @param map The map the allocation is for. |
---|
595 | * @param buffer The buffer the indirect block is accessed by. |
---|
596 | * @param indirect The index index in the inode's block table. |
---|
597 | * @param index The index in the indirect table of the block. |
---|
598 | * @return int The error number (errno). No error if 0. |
---|
599 | */ |
---|
600 | static int |
---|
601 | rtems_rfs_block_map_indirect_shrink (rtems_rfs_file_system* fs, |
---|
602 | rtems_rfs_block_map* map, |
---|
603 | rtems_rfs_buffer_handle* buffer, |
---|
604 | rtems_rfs_block_no indirect, |
---|
605 | rtems_rfs_block_no index) |
---|
606 | { |
---|
607 | int rc = 0; |
---|
608 | |
---|
609 | /* |
---|
610 | * If this is the first block in the indirect table (index == 0), ie the last |
---|
611 | * block to be freed and the indirect block is now also free, or we have only |
---|
612 | * one indirect table and we can fit the remaining blocks into the inode, |
---|
613 | * then either move to the next indirect block or move the remaining blocks |
---|
614 | * into the inode and free the indirect table's block. |
---|
615 | */ |
---|
616 | if ((index == 0) || |
---|
617 | ((indirect == 0) && (index == RTEMS_RFS_INODE_BLOCKS))) |
---|
618 | { |
---|
619 | rtems_rfs_block_no block_to_free = map->blocks[indirect]; |
---|
620 | |
---|
621 | if ((indirect == 0) && (index == RTEMS_RFS_INODE_BLOCKS)) |
---|
622 | { |
---|
623 | /* |
---|
624 | * Move to direct inode access. |
---|
625 | */ |
---|
626 | int b; |
---|
627 | for (b = 0; b < RTEMS_RFS_INODE_BLOCKS; b++) |
---|
628 | map->blocks[b] = rtems_rfs_block_get_number (buffer, b); |
---|
629 | |
---|
630 | rtems_rfs_buffer_handle_reset (buffer); |
---|
631 | } |
---|
632 | else |
---|
633 | { |
---|
634 | /* |
---|
635 | * One less singly indirect block in the inode. |
---|
636 | */ |
---|
637 | map->blocks[indirect] = 0; |
---|
638 | } |
---|
639 | |
---|
640 | rc = rtems_rfs_group_bitmap_free (fs, false, block_to_free); |
---|
641 | if (rc > 0) |
---|
642 | return rc; |
---|
643 | |
---|
644 | map->last_map_block = block_to_free; |
---|
645 | } |
---|
646 | |
---|
647 | return rc; |
---|
648 | } |
---|
649 | |
---|
650 | int |
---|
651 | rtems_rfs_block_map_shrink (rtems_rfs_file_system* fs, |
---|
652 | rtems_rfs_block_map* map, |
---|
653 | size_t blocks) |
---|
654 | { |
---|
655 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BLOCK_MAP_SHRINK)) |
---|
656 | printf ("rtems-rfs: block-map-shrink: entry: blocks=%ld count=%lu\n", |
---|
657 | blocks, map->size.count); |
---|
658 | |
---|
659 | if (map->size.count == 0) |
---|
660 | return 0; |
---|
661 | |
---|
662 | if (blocks > map->size.count) |
---|
663 | blocks = map->size.count; |
---|
664 | |
---|
665 | while (blocks) |
---|
666 | { |
---|
667 | rtems_rfs_block_no block; |
---|
668 | rtems_rfs_block_no block_to_free; |
---|
669 | int rc; |
---|
670 | |
---|
671 | block = map->size.count - 1; |
---|
672 | |
---|
673 | if (block < RTEMS_RFS_INODE_BLOCKS) |
---|
674 | { |
---|
675 | /* |
---|
676 | * We have less than RTEMS_RFS_INODE_BLOCKS so they are held in the |
---|
677 | * inode. |
---|
678 | */ |
---|
679 | block_to_free = map->blocks[block]; |
---|
680 | map->blocks[block] = 0; |
---|
681 | } |
---|
682 | else |
---|
683 | { |
---|
684 | /* |
---|
685 | * Single indirect access is occuring. It could still be doubly indirect. |
---|
686 | * |
---|
687 | * The 'direct' variable is the offset in to the indirect table of |
---|
688 | * blocks, and 'singly' is the inode block index of the singly indirect |
---|
689 | * table of block numbers. |
---|
690 | */ |
---|
691 | rtems_rfs_block_no direct; |
---|
692 | rtems_rfs_block_no singly; |
---|
693 | |
---|
694 | direct = block % fs->blocks_per_block; |
---|
695 | singly = block / fs->blocks_per_block; |
---|
696 | |
---|
697 | if (block < fs->block_map_singly_blocks) |
---|
698 | { |
---|
699 | /* |
---|
700 | * Request the indirect block and then obtain the block number from the |
---|
701 | * indirect block. |
---|
702 | */ |
---|
703 | rc = rtems_rfs_buffer_handle_request (fs, &map->singly_buffer, |
---|
704 | map->blocks[singly], true); |
---|
705 | if (rc > 0) |
---|
706 | return rc; |
---|
707 | |
---|
708 | block_to_free = rtems_rfs_block_get_number (&map->singly_buffer, |
---|
709 | direct); |
---|
710 | |
---|
711 | rc = rtems_rfs_block_map_indirect_shrink (fs, map, &map->singly_buffer, |
---|
712 | singly, direct); |
---|
713 | if (rc) |
---|
714 | return rc; |
---|
715 | } |
---|
716 | else if (block < fs->block_map_doubly_blocks) |
---|
717 | { |
---|
718 | /* |
---|
719 | * Doubly indirect tables are being used. The 'doubly' variable is the |
---|
720 | * index in to the inode's block table and points to a singly indirect |
---|
721 | * table of block numbers. The 'doubly_singly' variable is the index |
---|
722 | * into the doubly indirect table pointing to the singly indirect table |
---|
723 | * of block numbers that form the map. This is used later to determine |
---|
724 | * if the current doubly indirect table needs to be freed. The 'direct' |
---|
725 | * value is still valid for doubly indirect tables. |
---|
726 | */ |
---|
727 | rtems_rfs_block_no doubly; |
---|
728 | rtems_rfs_block_no doubly_singly; |
---|
729 | |
---|
730 | doubly = singly / fs->blocks_per_block; |
---|
731 | doubly_singly = singly % fs->blocks_per_block; |
---|
732 | |
---|
733 | rc = rtems_rfs_buffer_handle_request (fs, &map->doubly_buffer, |
---|
734 | map->blocks[doubly], true); |
---|
735 | if (rc > 0) |
---|
736 | return rc; |
---|
737 | |
---|
738 | singly = rtems_rfs_block_get_number (&map->doubly_buffer, |
---|
739 | doubly_singly); |
---|
740 | |
---|
741 | /* |
---|
742 | * Read the singly indirect table and get the block number. |
---|
743 | */ |
---|
744 | rc = rtems_rfs_buffer_handle_request (fs, &map->singly_buffer, |
---|
745 | singly, true); |
---|
746 | if (rc > 0) |
---|
747 | return rc; |
---|
748 | |
---|
749 | block_to_free = rtems_rfs_block_get_number (&map->singly_buffer, |
---|
750 | direct); |
---|
751 | |
---|
752 | if (direct == 0) |
---|
753 | { |
---|
754 | rc = rtems_rfs_group_bitmap_free (fs, false, singly); |
---|
755 | if (rc > 0) |
---|
756 | return rc; |
---|
757 | |
---|
758 | map->last_map_block = singly; |
---|
759 | |
---|
760 | rc = rtems_rfs_block_map_indirect_shrink (fs, map, &map->doubly_buffer, |
---|
761 | doubly, doubly_singly); |
---|
762 | if (rc) |
---|
763 | return rc; |
---|
764 | } |
---|
765 | } |
---|
766 | else |
---|
767 | { |
---|
768 | rc = EIO; |
---|
769 | break; |
---|
770 | } |
---|
771 | } |
---|
772 | rc = rtems_rfs_group_bitmap_free (fs, false, block_to_free); |
---|
773 | if (rc > 0) |
---|
774 | return rc; |
---|
775 | map->size.count--; |
---|
776 | map->size.offset = 0; |
---|
777 | map->last_data_block = block_to_free; |
---|
778 | map->dirty = true; |
---|
779 | blocks--; |
---|
780 | } |
---|
781 | |
---|
782 | if (map->size.count == 0) |
---|
783 | { |
---|
784 | map->last_map_block = 0; |
---|
785 | map->last_data_block = 0; |
---|
786 | } |
---|
787 | |
---|
788 | /* |
---|
789 | * Keep the position inside the map. |
---|
790 | */ |
---|
791 | if (rtems_rfs_block_pos_past_end (&map->bpos, &map->size)) |
---|
792 | rtems_rfs_block_size_get_bpos (&map->size, &map->bpos); |
---|
793 | |
---|
794 | return 0; |
---|
795 | } |
---|
796 | |
---|
797 | int |
---|
798 | rtems_rfs_block_map_free_all (rtems_rfs_file_system* fs, |
---|
799 | rtems_rfs_block_map* map) |
---|
800 | { |
---|
801 | return rtems_rfs_block_map_shrink (fs, map, map->size.count); |
---|
802 | } |
---|