1 | /*
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2 | * res_gdt.c --- reserve blocks for growing the group descriptor table
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3 | * during online resizing.
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4 | *
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5 | * Copyright (C) 2002 Andreas Dilger
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6 | *
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7 | * %Begin-Header%
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8 | * This file may be redistributed under the terms of the GNU Public
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9 | * License.
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10 | * %End-Header%
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11 | */
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12 |
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13 | #include <stdio.h>
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14 | #include <string.h>
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15 | #include <time.h>
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16 | #include "ext2_fs.h"
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17 | #include "ext2fs.h"
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18 |
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19 | /*
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20 | * Iterate through the groups which hold BACKUP superblock/GDT copies in an
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21 | * ext3 filesystem. The counters should be initialized to 1, 5, and 7 before
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22 | * calling this for the first time. In a sparse filesystem it will be the
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23 | * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
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24 | * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
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25 | */
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26 | static unsigned int list_backups(ext2_filsys fs, unsigned int *three,
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27 | unsigned int *five, unsigned int *seven)
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28 | {
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29 | unsigned int *min = three;
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30 | int mult = 3;
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31 | unsigned int ret;
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32 |
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33 | if (!(fs->super->s_feature_ro_compat &
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34 | EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
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35 | ret = *min;
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36 | *min += 1;
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37 | return ret;
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38 | }
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39 |
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40 | if (*five < *min) {
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41 | min = five;
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42 | mult = 5;
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43 | }
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44 | if (*seven < *min) {
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45 | min = seven;
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46 | mult = 7;
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47 | }
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48 |
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49 | ret = *min;
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50 | *min *= mult;
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51 |
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52 | return ret;
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53 | }
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54 |
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55 | /*
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56 | * This code assumes that the reserved blocks have already been marked in-use
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57 | * during ext2fs_initialize(), so that they are not allocated for other
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58 | * uses before we can add them to the resize inode (which has to come
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59 | * after the creation of the inode table).
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60 | */
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61 | errcode_t ext2fs_create_resize_inode(ext2_filsys fs)
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62 | {
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63 | errcode_t retval, retval2;
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64 | struct ext2_super_block *sb;
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65 | struct ext2_inode inode;
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66 | __u32 *dindir_buf, *gdt_buf;
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67 | int rsv_add;
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68 | unsigned long long apb, inode_size;
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69 | blk_t dindir_blk, rsv_off, gdt_off, gdt_blk;
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70 | int dindir_dirty = 0, inode_dirty = 0;
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71 |
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72 | EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
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73 |
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74 | sb = fs->super;
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75 |
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76 | retval = ext2fs_get_mem(2 * fs->blocksize, (void *)&dindir_buf);
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77 | if (retval)
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78 | goto out_free;
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79 | gdt_buf = (__u32 *)((char *)dindir_buf + fs->blocksize);
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80 |
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81 | retval = ext2fs_read_inode(fs, EXT2_RESIZE_INO, &inode);
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82 | if (retval)
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83 | goto out_free;
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84 |
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85 | /* Maximum possible file size (we donly use the dindirect blocks) */
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86 | apb = EXT2_ADDR_PER_BLOCK(sb);
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87 | rsv_add = fs->blocksize / 512;
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88 | if ((dindir_blk = inode.i_block[EXT2_DIND_BLOCK])) {
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89 | #ifdef RES_GDT_DEBUG
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90 | printf("reading GDT dindir %u\n", dindir_blk);
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91 | #endif
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92 | retval = ext2fs_read_ind_block(fs, dindir_blk, dindir_buf);
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93 | if (retval)
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94 | goto out_inode;
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95 | } else {
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96 | blk_t goal = 3 + sb->s_reserved_gdt_blocks +
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97 | fs->desc_blocks + fs->inode_blocks_per_group;
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98 |
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99 | retval = ext2fs_alloc_block(fs, goal, 0, &dindir_blk);
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100 | if (retval)
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101 | goto out_free;
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102 | inode.i_mode = LINUX_S_IFREG | 0600;
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103 | inode.i_links_count = 1;
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104 | inode.i_block[EXT2_DIND_BLOCK] = dindir_blk;
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105 | inode.i_blocks = rsv_add;
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106 | memset(dindir_buf, 0, fs->blocksize);
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107 | #ifdef RES_GDT_DEBUG
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108 | printf("allocated GDT dindir %u\n", dindir_blk);
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109 | #endif
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110 | dindir_dirty = inode_dirty = 1;
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111 | inode_size = apb*apb + apb + EXT2_NDIR_BLOCKS;
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112 | inode_size *= fs->blocksize;
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113 | inode.i_size = inode_size & 0xFFFFFFFF;
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114 | inode.i_size_high = (inode_size >> 32) & 0xFFFFFFFF;
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115 | if(inode.i_size_high) {
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116 | sb->s_feature_ro_compat |=
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117 | EXT2_FEATURE_RO_COMPAT_LARGE_FILE;
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118 | }
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119 | inode.i_ctime = time(0);
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120 | }
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121 |
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122 | for (rsv_off = 0, gdt_off = fs->desc_blocks,
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123 | gdt_blk = sb->s_first_data_block + 1 + fs->desc_blocks;
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124 | rsv_off < sb->s_reserved_gdt_blocks;
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125 | rsv_off++, gdt_off++, gdt_blk++) {
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126 | unsigned int three = 1, five = 5, seven = 7;
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127 | unsigned int grp, last = 0;
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128 | int gdt_dirty = 0;
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129 |
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130 | gdt_off %= apb;
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131 | if (!dindir_buf[gdt_off]) {
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132 | /* FIXME XXX XXX
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133 | blk_t new_blk;
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134 |
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135 | retval = ext2fs_new_block(fs, gdt_blk, 0, &new_blk);
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136 | if (retval)
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137 | goto out_free;
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138 | if (new_blk != gdt_blk) {
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139 | // XXX free block
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140 | retval = -1; // XXX
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141 | }
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142 | */
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143 | gdt_dirty = dindir_dirty = inode_dirty = 1;
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144 | memset(gdt_buf, 0, fs->blocksize);
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145 | dindir_buf[gdt_off] = gdt_blk;
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146 | inode.i_blocks += rsv_add;
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147 | #ifdef RES_GDT_DEBUG
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148 | printf("added primary GDT block %u at %u[%u]\n",
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149 | gdt_blk, dindir_blk, gdt_off);
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150 | #endif
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151 | } else if (dindir_buf[gdt_off] == gdt_blk) {
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152 | #ifdef RES_GDT_DEBUG
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153 | printf("reading primary GDT block %u\n", gdt_blk);
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154 | #endif
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155 | retval = ext2fs_read_ind_block(fs, gdt_blk, gdt_buf);
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156 | if (retval)
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157 | goto out_dindir;
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158 | } else {
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159 | #ifdef RES_GDT_DEBUG
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160 | printf("bad primary GDT %u != %u at %u[%u]\n",
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161 | dindir_buf[gdt_off], gdt_blk,dindir_blk,gdt_off);
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162 | #endif
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163 | retval = EXT2_ET_RESIZE_INODE_CORRUPT;
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164 | goto out_dindir;
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165 | }
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166 |
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167 | while ((grp = list_backups(fs, &three, &five, &seven)) <
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168 | fs->group_desc_count) {
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169 | blk_t expect = gdt_blk + grp * sb->s_blocks_per_group;
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170 |
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171 | if (!gdt_buf[last]) {
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172 | #ifdef RES_GDT_DEBUG
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173 | printf("added backup GDT %u grp %u@%u[%u]\n",
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174 | expect, grp, gdt_blk, last);
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175 | #endif
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176 | gdt_buf[last] = expect;
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177 | inode.i_blocks += rsv_add;
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178 | gdt_dirty = inode_dirty = 1;
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179 | } else if (gdt_buf[last] != expect) {
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180 | #ifdef RES_GDT_DEBUG
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181 | printf("bad backup GDT %u != %u at %u[%u]\n",
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182 | gdt_buf[last], expect, gdt_blk, last);
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183 | #endif
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184 | retval = EXT2_ET_RESIZE_INODE_CORRUPT;
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185 | goto out_dindir;
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186 | }
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187 | last++;
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188 | }
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189 | if (gdt_dirty) {
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190 | #ifdef RES_GDT_DEBUG
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191 | printf("writing primary GDT block %u\n", gdt_blk);
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192 | #endif
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193 | retval = ext2fs_write_ind_block(fs, gdt_blk, gdt_buf);
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194 | if (retval)
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195 | goto out_dindir;
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196 | }
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197 | }
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198 |
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199 | out_dindir:
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200 | if (dindir_dirty) {
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201 | retval2 = ext2fs_write_ind_block(fs, dindir_blk, dindir_buf);
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202 | if (!retval)
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203 | retval = retval2;
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204 | }
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205 | out_inode:
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206 | #ifdef RES_GDT_DEBUG
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207 | printf("inode.i_blocks = %u, i_size = %u\n", inode.i_blocks,
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208 | inode.i_size);
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209 | #endif
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210 | if (inode_dirty) {
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211 | inode.i_atime = inode.i_mtime = time(0);
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212 | retval2 = ext2fs_write_inode(fs, EXT2_RESIZE_INO, &inode);
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213 | if (!retval)
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214 | retval = retval2;
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215 | }
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216 | out_free:
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217 | ext2fs_free_mem((void *)&dindir_buf);
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218 | return retval;
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219 | }
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220 |
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