1 | /*
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2 | * alloc.c --- allocate new inodes, blocks for ext2fs
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3 | *
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4 | * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
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5 | *
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6 | * %Begin-Header%
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7 | * This file may be redistributed under the terms of the GNU Public
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8 | * License.
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9 | * %End-Header%
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10 | *
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11 | */
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12 |
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13 | #include <stdio.h>
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14 | #if HAVE_UNISTD_H
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15 | #include <unistd.h>
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16 | #endif
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17 | #include <time.h>
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18 | #include <string.h>
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19 | #if HAVE_SYS_STAT_H
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20 | #include <sys/stat.h>
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21 | #endif
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22 | #if HAVE_SYS_TYPES_H
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23 | #include <sys/types.h>
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24 | #endif
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25 |
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26 | #include "ext2_fs.h"
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27 | #include "ext2fs.h"
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28 |
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29 | /*
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30 | * Right now, just search forward from the parent directory's block
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31 | * group to find the next free inode.
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32 | *
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33 | * Should have a special policy for directories.
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34 | */
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35 | errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir,
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36 | int mode EXT2FS_ATTR((unused)),
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37 | ext2fs_inode_bitmap map, ext2_ino_t *ret)
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38 | {
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39 | ext2_ino_t dir_group = 0;
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40 | ext2_ino_t i;
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41 | ext2_ino_t start_inode;
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42 |
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43 | EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
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44 |
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45 | if (!map)
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46 | map = fs->inode_map;
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47 | if (!map)
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48 | return EXT2_ET_NO_INODE_BITMAP;
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49 |
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50 | if (dir > 0)
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51 | dir_group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super);
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52 |
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53 | start_inode = (dir_group * EXT2_INODES_PER_GROUP(fs->super)) + 1;
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54 | if (start_inode < EXT2_FIRST_INODE(fs->super))
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55 | start_inode = EXT2_FIRST_INODE(fs->super);
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56 | i = start_inode;
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57 |
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58 | do {
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59 | if (!ext2fs_fast_test_inode_bitmap(map, i))
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60 | break;
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61 | i++;
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62 | if (i > fs->super->s_inodes_count)
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63 | i = EXT2_FIRST_INODE(fs->super);
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64 | } while (i != start_inode);
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65 |
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66 | if (ext2fs_test_inode_bitmap(map, i))
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67 | return EXT2_ET_INODE_ALLOC_FAIL;
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68 | *ret = i;
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69 | return 0;
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70 | }
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71 |
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72 | /*
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73 | * Stupid algorithm --- we now just search forward starting from the
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74 | * goal. Should put in a smarter one someday....
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75 | */
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76 | errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal,
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77 | ext2fs_block_bitmap map, blk_t *ret)
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78 | {
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79 | blk_t i;
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80 |
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81 | EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
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82 |
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83 | if (!map)
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84 | map = fs->block_map;
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85 | if (!map)
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86 | return EXT2_ET_NO_BLOCK_BITMAP;
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87 | if (!goal || (goal >= fs->super->s_blocks_count))
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88 | goal = fs->super->s_first_data_block;
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89 | i = goal;
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90 | do {
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91 | if (!ext2fs_fast_test_block_bitmap(map, i)) {
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92 | *ret = i;
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93 | return 0;
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94 | }
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95 | i++;
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96 | if (i >= fs->super->s_blocks_count)
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97 | i = fs->super->s_first_data_block;
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98 | } while (i != goal);
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99 | return EXT2_ET_BLOCK_ALLOC_FAIL;
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100 | }
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101 |
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102 | /*
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103 | * This function zeros out the allocated block, and updates all of the
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104 | * appropriate filesystem records.
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105 | */
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106 | errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal,
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107 | char *block_buf, blk_t *ret)
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108 | {
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109 | errcode_t retval;
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110 | blk_t block;
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111 | char *buf = 0;
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112 |
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113 | if (!block_buf) {
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114 | retval = ext2fs_get_mem(fs->blocksize, &buf);
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115 | if (retval)
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116 | return retval;
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117 | block_buf = buf;
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118 | }
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119 | memset(block_buf, 0, fs->blocksize);
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120 |
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121 | if (!fs->block_map) {
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122 | retval = ext2fs_read_block_bitmap(fs);
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123 | if (retval)
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124 | goto fail;
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125 | }
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126 |
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127 | retval = ext2fs_new_block(fs, goal, 0, &block);
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128 | if (retval)
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129 | goto fail;
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130 |
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131 | retval = io_channel_write_blk(fs->io, block, 1, block_buf);
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132 | if (retval)
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133 | goto fail;
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134 |
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135 | ext2fs_block_alloc_stats(fs, block, +1);
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136 | *ret = block;
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137 | return 0;
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138 |
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139 | fail:
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140 | if (buf)
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141 | ext2fs_free_mem(&buf);
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142 | return retval;
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143 | }
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144 |
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145 | errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish,
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146 | int num, ext2fs_block_bitmap map, blk_t *ret)
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147 | {
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148 | blk_t b = start;
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149 |
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150 | EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
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151 |
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152 | if (!map)
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153 | map = fs->block_map;
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154 | if (!map)
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155 | return EXT2_ET_NO_BLOCK_BITMAP;
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156 | if (!b)
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157 | b = fs->super->s_first_data_block;
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158 | if (!finish)
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159 | finish = start;
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160 | if (!num)
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161 | num = 1;
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162 | do {
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163 | if (b+num-1 > fs->super->s_blocks_count)
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164 | b = fs->super->s_first_data_block;
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165 | if (ext2fs_fast_test_block_bitmap_range(map, b, num)) {
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166 | *ret = b;
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167 | return 0;
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168 | }
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169 | b++;
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170 | } while (b != finish);
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171 | return EXT2_ET_BLOCK_ALLOC_FAIL;
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172 | }
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173 |
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