1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * mkfs_ext2: utility to create EXT2 filesystem
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4 | * inspired by genext2fs
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5 | *
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6 | * Busybox'ed (2009) by Vladimir Dronnikov <dronnikov@gmail.com>
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7 | *
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8 | * Licensed under GPLv2, see file LICENSE in this source tree.
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9 | */
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10 | #include "libbb.h"
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11 | #include <linux/fs.h>
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12 | #include <linux/ext2_fs.h>
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13 |
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14 | #define ENABLE_FEATURE_MKFS_EXT2_RESERVED_GDT 0
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15 | #define ENABLE_FEATURE_MKFS_EXT2_DIR_INDEX 1
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16 |
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17 | // from e2fsprogs
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18 | #define s_reserved_gdt_blocks s_padding1
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19 | #define s_mkfs_time s_reserved[0]
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20 | #define s_flags s_reserved[22]
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21 |
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22 | #define EXT2_HASH_HALF_MD4 1
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23 | #define EXT2_FLAGS_SIGNED_HASH 0x0001
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24 | #define EXT2_FLAGS_UNSIGNED_HASH 0x0002
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25 |
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26 | // storage helpers
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27 | char BUG_wrong_field_size(void);
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28 | #define STORE_LE(field, value) \
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29 | do { \
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30 | if (sizeof(field) == 4) \
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31 | field = SWAP_LE32(value); \
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32 | else if (sizeof(field) == 2) \
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33 | field = SWAP_LE16(value); \
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34 | else if (sizeof(field) == 1) \
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35 | field = (value); \
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36 | else \
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37 | BUG_wrong_field_size(); \
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38 | } while (0)
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39 |
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40 | #define FETCH_LE32(field) \
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41 | (sizeof(field) == 4 ? SWAP_LE32(field) : BUG_wrong_field_size())
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42 |
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43 | // All fields are little-endian
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44 | struct ext2_dir {
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45 | uint32_t inode1;
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46 | uint16_t rec_len1;
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47 | uint8_t name_len1;
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48 | uint8_t file_type1;
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49 | char name1[4];
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50 | uint32_t inode2;
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51 | uint16_t rec_len2;
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52 | uint8_t name_len2;
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53 | uint8_t file_type2;
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54 | char name2[4];
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55 | uint32_t inode3;
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56 | uint16_t rec_len3;
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57 | uint8_t name_len3;
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58 | uint8_t file_type3;
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59 | char name3[12];
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60 | };
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61 |
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62 | static unsigned int_log2(unsigned arg)
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63 | {
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64 | unsigned r = 0;
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65 | while ((arg >>= 1) != 0)
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66 | r++;
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67 | return r;
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68 | }
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69 |
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70 | // taken from mkfs_minix.c. libbb candidate?
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71 | // "uint32_t size", since we never use it for anything >32 bits
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72 | static uint32_t div_roundup(uint32_t size, uint32_t n)
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73 | {
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74 | // Overflow-resistant
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75 | uint32_t res = size / n;
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76 | if (res * n != size)
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77 | res++;
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78 | return res;
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79 | }
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80 |
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81 | static void allocate(uint8_t *bitmap, uint32_t blocksize, uint32_t start, uint32_t end)
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82 | {
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83 | uint32_t i;
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84 |
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85 | //bb_info_msg("ALLOC: [%u][%u][%u]: [%u-%u]:=[%x],[%x]", blocksize, start, end, start/8, blocksize - end/8 - 1, (1 << (start & 7)) - 1, (uint8_t)(0xFF00 >> (end & 7)));
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86 | memset(bitmap, 0, blocksize);
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87 | i = start / 8;
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88 | memset(bitmap, 0xFF, i);
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89 | bitmap[i] = (1 << (start & 7)) - 1; //0..7 => 00000000..01111111
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90 | i = end / 8;
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91 | bitmap[blocksize - i - 1] |= 0x7F00 >> (end & 7); //0..7 => 00000000..11111110
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92 | memset(bitmap + blocksize - i, 0xFF, i); // N.B. no overflow here!
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93 | }
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94 |
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95 | static uint32_t has_super(uint32_t x)
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96 | {
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97 | // 0, 1 and powers of 3, 5, 7 up to 2^32 limit
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98 | static const uint32_t supers[] = {
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99 | 0, 1, 3, 5, 7, 9, 25, 27, 49, 81, 125, 243, 343, 625, 729,
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100 | 2187, 2401, 3125, 6561, 15625, 16807, 19683, 59049, 78125,
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101 | 117649, 177147, 390625, 531441, 823543, 1594323, 1953125,
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102 | 4782969, 5764801, 9765625, 14348907, 40353607, 43046721,
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103 | 48828125, 129140163, 244140625, 282475249, 387420489,
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104 | 1162261467, 1220703125, 1977326743, 3486784401/* >2^31 */,
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105 | };
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106 | const uint32_t *sp = supers + ARRAY_SIZE(supers);
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107 | while (1) {
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108 | sp--;
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109 | if (x == *sp)
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110 | return 1;
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111 | if (x > *sp)
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112 | return 0;
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113 | }
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114 | }
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115 |
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116 | #define fd 3 /* predefined output descriptor */
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117 |
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118 | static void PUT(uint64_t off, void *buf, uint32_t size)
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119 | {
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120 | // bb_info_msg("PUT[%llu]:[%u]", off, size);
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121 | xlseek(fd, off, SEEK_SET);
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122 | xwrite(fd, buf, size);
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123 | }
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124 |
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125 | // 128 and 256-byte inodes:
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126 | // 128-byte inode is described by struct ext2_inode.
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127 | // 256-byte one just has these fields appended:
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128 | // __u16 i_extra_isize;
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129 | // __u16 i_pad1;
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130 | // __u32 i_ctime_extra; /* extra Change time (nsec << 2 | epoch) */
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131 | // __u32 i_mtime_extra; /* extra Modification time (nsec << 2 | epoch) */
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132 | // __u32 i_atime_extra; /* extra Access time (nsec << 2 | epoch) */
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133 | // __u32 i_crtime; /* File creation time */
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134 | // __u32 i_crtime_extra; /* extra File creation time (nsec << 2 | epoch)*/
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135 | // __u32 i_version_hi; /* high 32 bits for 64-bit version */
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136 | // the rest is padding.
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137 | //
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138 | // linux/ext2_fs.h has "#define i_size_high i_dir_acl" which suggests that even
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139 | // 128-byte inode is capable of describing large files (i_dir_acl is meaningful
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140 | // only for directories, which never need i_size_high).
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141 | //
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142 | // Standard mke2fs creates a filesystem with 256-byte inodes if it is
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143 | // bigger than 0.5GB.
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144 |
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145 | // Standard mke2fs 1.41.9:
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146 | // Usage: mke2fs [-c|-l filename] [-b block-size] [-f fragment-size]
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147 | // [-i bytes-per-inode] [-I inode-size] [-J journal-options]
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148 | // [-G meta group size] [-N number-of-inodes]
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149 | // [-m reserved-blocks-percentage] [-o creator-os]
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150 | // [-g blocks-per-group] [-L volume-label] [-M last-mounted-directory]
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151 | // [-O feature[,...]] [-r fs-revision] [-E extended-option[,...]]
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152 | // [-T fs-type] [-U UUID] [-jnqvFSV] device [blocks-count]
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153 | //
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154 | // Options not commented below are taken but silently ignored:
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155 | enum {
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156 | OPT_c = 1 << 0,
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157 | OPT_l = 1 << 1,
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158 | OPT_b = 1 << 2, // block size, in bytes
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159 | OPT_f = 1 << 3,
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160 | OPT_i = 1 << 4, // bytes per inode
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161 | OPT_I = 1 << 5, // custom inode size, in bytes
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162 | OPT_J = 1 << 6,
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163 | OPT_G = 1 << 7,
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164 | OPT_N = 1 << 8,
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165 | OPT_m = 1 << 9, // percentage of blocks reserved for superuser
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166 | OPT_o = 1 << 10,
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167 | OPT_g = 1 << 11,
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168 | OPT_L = 1 << 12, // label
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169 | OPT_M = 1 << 13,
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170 | OPT_O = 1 << 14,
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171 | OPT_r = 1 << 15,
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172 | OPT_E = 1 << 16,
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173 | OPT_T = 1 << 17,
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174 | OPT_U = 1 << 18,
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175 | OPT_j = 1 << 19,
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176 | OPT_n = 1 << 20, // dry run: do not write anything
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177 | OPT_q = 1 << 21,
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178 | OPT_v = 1 << 22,
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179 | OPT_F = 1 << 23,
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180 | OPT_S = 1 << 24,
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181 | //OPT_V = 1 << 25, // -V version. bbox applets don't support that
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182 | };
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183 |
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184 | int mkfs_ext2_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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185 | int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
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186 | {
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187 | unsigned i, pos, n;
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188 | unsigned bs, bpi;
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189 | unsigned blocksize, blocksize_log2;
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190 | unsigned inodesize, user_inodesize;
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191 | unsigned reserved_percent = 5;
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192 | unsigned long long kilobytes;
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193 | uint32_t nblocks, nblocks_full;
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194 | uint32_t nreserved;
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195 | uint32_t ngroups;
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196 | uint32_t bytes_per_inode;
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197 | uint32_t first_block;
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198 | uint32_t inodes_per_group;
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199 | uint32_t group_desc_blocks;
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200 | uint32_t inode_table_blocks;
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201 | uint32_t lost_and_found_blocks;
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202 | time_t timestamp;
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203 | const char *label = "";
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204 | struct stat st;
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205 | struct ext2_super_block *sb; // superblock
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206 | struct ext2_group_desc *gd; // group descriptors
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207 | struct ext2_inode *inode;
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208 | struct ext2_dir *dir;
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209 | uint8_t *buf;
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210 |
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211 | // using global "option_mask32" instead of local "opts":
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212 | // we are register starved here
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213 | opt_complementary = "-1:b+:i+:I+:m+";
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214 | /*opts =*/ getopt32(argv, "cl:b:f:i:I:J:G:N:m:o:g:L:M:O:r:E:T:U:jnqvFS",
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215 | /*lbfi:*/ NULL, &bs, NULL, &bpi,
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216 | /*IJGN:*/ &user_inodesize, NULL, NULL, NULL,
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217 | /*mogL:*/ &reserved_percent, NULL, NULL, &label,
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218 | /*MOrE:*/ NULL, NULL, NULL, NULL,
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219 | /*TU:*/ NULL, NULL);
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220 | argv += optind; // argv[0] -- device
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221 |
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222 | // open the device, check the device is a block device
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223 | xmove_fd(xopen(argv[0], O_WRONLY), fd);
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224 | xfstat(fd, &st, argv[0]);
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225 | if (!S_ISBLK(st.st_mode) && !(option_mask32 & OPT_F))
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226 | bb_error_msg_and_die("%s: not a block device", argv[0]);
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227 |
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228 | // check if it is mounted
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229 | // N.B. what if we format a file? find_mount_point will return false negative since
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230 | // it is loop block device which is mounted!
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231 | if (find_mount_point(argv[0], 0))
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232 | bb_error_msg_and_die("can't format mounted filesystem");
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233 |
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234 | // get size in kbytes
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235 | kilobytes = get_volume_size_in_bytes(fd, argv[1], 1024, /*extend:*/ !(option_mask32 & OPT_n)) / 1024;
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236 |
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237 | bytes_per_inode = 16384;
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238 | if (kilobytes < 512*1024)
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239 | bytes_per_inode = 4096;
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240 | if (kilobytes < 3*1024)
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241 | bytes_per_inode = 8192;
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242 | if (option_mask32 & OPT_i)
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243 | bytes_per_inode = bpi;
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244 |
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245 | // Determine block size and inode size
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246 | // block size is a multiple of 1024
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247 | // inode size is a multiple of 128
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248 | blocksize = 1024;
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249 | inodesize = sizeof(struct ext2_inode); // 128
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250 | if (kilobytes >= 512*1024) { // mke2fs 1.41.9 compat
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251 | blocksize = 4096;
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252 | inodesize = 256;
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253 | }
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254 | if (EXT2_MAX_BLOCK_SIZE > 4096) {
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255 | // kilobytes >> 22 == size in 4gigabyte chunks.
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256 | // if size >= 16k gigs, blocksize must be increased.
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257 | // Try "mke2fs -F image $((16 * 1024*1024*1024))"
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258 | while ((kilobytes >> 22) >= blocksize)
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259 | blocksize *= 2;
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260 | }
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261 | if (option_mask32 & OPT_b)
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262 | blocksize = bs;
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263 | if (blocksize < EXT2_MIN_BLOCK_SIZE
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264 | || blocksize > EXT2_MAX_BLOCK_SIZE
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265 | || (blocksize & (blocksize - 1)) // not power of 2
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266 | ) {
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267 | bb_error_msg_and_die("blocksize %u is bad", blocksize);
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268 | }
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269 | // Do we have custom inode size?
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270 | if (option_mask32 & OPT_I) {
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271 | if (user_inodesize < sizeof(*inode)
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272 | || user_inodesize > blocksize
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273 | || (user_inodesize & (user_inodesize - 1)) // not power of 2
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274 | ) {
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275 | bb_error_msg("-%c is bad", 'I');
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276 | } else {
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277 | inodesize = user_inodesize;
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278 | }
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279 | }
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280 |
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281 | if ((int32_t)bytes_per_inode < blocksize)
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282 | bb_error_msg_and_die("-%c is bad", 'i');
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283 | // number of bits in one block, i.e. 8*blocksize
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284 | #define blocks_per_group (8 * blocksize)
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285 | first_block = (EXT2_MIN_BLOCK_SIZE == blocksize);
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286 | blocksize_log2 = int_log2(blocksize);
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287 |
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288 | // Determine number of blocks
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289 | kilobytes >>= (blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE);
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290 | nblocks = kilobytes;
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291 | if (nblocks != kilobytes)
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292 | bb_error_msg_and_die("block count doesn't fit in 32 bits");
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293 | #define kilobytes kilobytes_unused_after_this
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294 | // Experimentally, standard mke2fs won't work on images smaller than 60k
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295 | if (nblocks < 60)
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296 | bb_error_msg_and_die("need >= 60 blocks");
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297 |
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298 | // How many reserved blocks?
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299 | if (reserved_percent > 50)
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300 | bb_error_msg_and_die("-%c is bad", 'm');
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301 | nreserved = (uint64_t)nblocks * reserved_percent / 100;
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302 |
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303 | // N.B. killing e2fsprogs feature! Unused blocks don't account in calculations
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304 | nblocks_full = nblocks;
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305 |
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306 | // If last block group is too small, nblocks may be decreased in order
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307 | // to discard it, and control returns here to recalculate some
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308 | // parameters.
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309 | // Note: blocksize and bytes_per_inode are never recalculated.
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310 | retry:
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311 | // N.B. a block group can have no more than blocks_per_group blocks
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312 | ngroups = div_roundup(nblocks - first_block, blocks_per_group);
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313 |
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314 | group_desc_blocks = div_roundup(ngroups, blocksize / sizeof(*gd));
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315 | // TODO: reserved blocks must be marked as such in the bitmaps,
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316 | // or resulting filesystem is corrupt
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317 | if (ENABLE_FEATURE_MKFS_EXT2_RESERVED_GDT) {
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318 | /*
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319 | * From e2fsprogs: Calculate the number of GDT blocks to reserve for online
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320 | * filesystem growth.
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321 | * The absolute maximum number of GDT blocks we can reserve is determined by
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322 | * the number of block pointers that can fit into a single block.
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323 | * We set it at 1024x the current filesystem size, or
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324 | * the upper block count limit (2^32), whichever is lower.
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325 | */
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326 | uint32_t reserved_group_desc_blocks = 0xFFFFFFFF; // maximum block number
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327 | if (nblocks < reserved_group_desc_blocks / 1024)
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328 | reserved_group_desc_blocks = nblocks * 1024;
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329 | reserved_group_desc_blocks = div_roundup(reserved_group_desc_blocks - first_block, blocks_per_group);
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330 | reserved_group_desc_blocks = div_roundup(reserved_group_desc_blocks, blocksize / sizeof(*gd)) - group_desc_blocks;
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331 | if (reserved_group_desc_blocks > blocksize / sizeof(uint32_t))
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332 | reserved_group_desc_blocks = blocksize / sizeof(uint32_t);
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333 | //TODO: STORE_LE(sb->s_reserved_gdt_blocks, reserved_group_desc_blocks);
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334 | group_desc_blocks += reserved_group_desc_blocks;
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335 | }
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336 |
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337 | {
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338 | // N.B. e2fsprogs does as follows!
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339 | uint32_t overhead, remainder;
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340 | // ninodes is the max number of inodes in this filesystem
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341 | uint32_t ninodes = ((uint64_t) nblocks_full * blocksize) / bytes_per_inode;
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342 | if (ninodes < EXT2_GOOD_OLD_FIRST_INO+1)
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343 | ninodes = EXT2_GOOD_OLD_FIRST_INO+1;
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344 | inodes_per_group = div_roundup(ninodes, ngroups);
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345 | // minimum number because the first EXT2_GOOD_OLD_FIRST_INO-1 are reserved
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346 | if (inodes_per_group < 16)
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347 | inodes_per_group = 16;
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348 | // a block group can't have more inodes than blocks
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349 | if (inodes_per_group > blocks_per_group)
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350 | inodes_per_group = blocks_per_group;
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351 | // adjust inodes per group so they completely fill the inode table blocks in the descriptor
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352 | inodes_per_group = (div_roundup(inodes_per_group * inodesize, blocksize) * blocksize) / inodesize;
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353 | // make sure the number of inodes per group is a multiple of 8
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354 | inodes_per_group &= ~7;
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355 | inode_table_blocks = div_roundup(inodes_per_group * inodesize, blocksize);
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356 |
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357 | // to be useful, lost+found should occupy at least 2 blocks (but not exceeding 16*1024 bytes),
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358 | // and at most EXT2_NDIR_BLOCKS. So reserve these blocks right now
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359 | /* Or e2fsprogs comment verbatim (what does it mean?):
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360 | * Ensure that lost+found is at least 2 blocks, so we always
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361 | * test large empty blocks for big-block filesystems. */
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362 | lost_and_found_blocks = MIN(EXT2_NDIR_BLOCKS, 16 >> (blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE));
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363 |
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364 | // the last group needs more attention: isn't it too small for possible overhead?
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365 | overhead = (has_super(ngroups - 1) ? (1/*sb*/ + group_desc_blocks) : 0) + 1/*bbmp*/ + 1/*ibmp*/ + inode_table_blocks;
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366 | remainder = (nblocks - first_block) % blocks_per_group;
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367 | ////can't happen, nblocks >= 60 guarantees this
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368 | ////if ((1 == ngroups)
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369 | //// && remainder
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370 | //// && (remainder < overhead + 1/* "/" */ + lost_and_found_blocks)
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371 | ////) {
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372 | //// bb_error_msg_and_die("way small device");
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373 | ////}
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374 |
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375 | // Standard mke2fs uses 50. Looks like a bug in our calculation
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376 | // of "remainder" or "overhead" - we don't match standard mke2fs
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377 | // when we transition from one group to two groups
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378 | // (a bit after 8M image size), but it works for two->three groups
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379 | // transition (at 16M).
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380 | if (remainder && (remainder < overhead + 50)) {
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381 | //bb_info_msg("CHOP[%u]", remainder);
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382 | nblocks -= remainder;
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383 | goto retry;
|
---|
384 | }
|
---|
385 | }
|
---|
386 |
|
---|
387 | if (nblocks_full - nblocks)
|
---|
388 | printf("warning: %u blocks unused\n\n", nblocks_full - nblocks);
|
---|
389 | printf(
|
---|
390 | "Filesystem label=%s\n"
|
---|
391 | "OS type: Linux\n"
|
---|
392 | "Block size=%u (log=%u)\n"
|
---|
393 | "Fragment size=%u (log=%u)\n"
|
---|
394 | "%u inodes, %u blocks\n"
|
---|
395 | "%u blocks (%u%%) reserved for the super user\n"
|
---|
396 | "First data block=%u\n"
|
---|
397 | "Maximum filesystem blocks=%u\n"
|
---|
398 | "%u block groups\n"
|
---|
399 | "%u blocks per group, %u fragments per group\n"
|
---|
400 | "%u inodes per group"
|
---|
401 | , label
|
---|
402 | , blocksize, blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE
|
---|
403 | , blocksize, blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE
|
---|
404 | , inodes_per_group * ngroups, nblocks
|
---|
405 | , nreserved, reserved_percent
|
---|
406 | , first_block
|
---|
407 | , group_desc_blocks * (blocksize / (unsigned)sizeof(*gd)) * blocks_per_group
|
---|
408 | , ngroups
|
---|
409 | , blocks_per_group, blocks_per_group
|
---|
410 | , inodes_per_group
|
---|
411 | );
|
---|
412 | {
|
---|
413 | const char *fmt = "\nSuperblock backups stored on blocks:\n"
|
---|
414 | "\t%u";
|
---|
415 | pos = first_block;
|
---|
416 | for (i = 1; i < ngroups; i++) {
|
---|
417 | pos += blocks_per_group;
|
---|
418 | if (has_super(i)) {
|
---|
419 | printf(fmt, (unsigned)pos);
|
---|
420 | fmt = ", %u";
|
---|
421 | }
|
---|
422 | }
|
---|
423 | }
|
---|
424 | bb_putchar('\n');
|
---|
425 |
|
---|
426 | if (option_mask32 & OPT_n) {
|
---|
427 | if (ENABLE_FEATURE_CLEAN_UP)
|
---|
428 | close(fd);
|
---|
429 | return EXIT_SUCCESS;
|
---|
430 | }
|
---|
431 |
|
---|
432 | // TODO: 3/5 refuse if mounted
|
---|
433 | // TODO: 4/5 compat options
|
---|
434 | // TODO: 1/5 sanity checks
|
---|
435 | // TODO: 0/5 more verbose error messages
|
---|
436 | // TODO: 4/5 bigendianness: recheck, wait for ARM reporters
|
---|
437 | // TODO: 2/5 reserved GDT: how to mark but not allocate?
|
---|
438 | // TODO: 3/5 dir_index?
|
---|
439 |
|
---|
440 | // fill the superblock
|
---|
441 | sb = xzalloc(1024);
|
---|
442 | STORE_LE(sb->s_rev_level, EXT2_DYNAMIC_REV); // revision 1 filesystem
|
---|
443 | STORE_LE(sb->s_magic, EXT2_SUPER_MAGIC);
|
---|
444 | STORE_LE(sb->s_inode_size, inodesize);
|
---|
445 | // set "Required extra isize" and "Desired extra isize" fields to 28
|
---|
446 | if (inodesize != sizeof(*inode))
|
---|
447 | STORE_LE(sb->s_reserved[21], 0x001C001C);
|
---|
448 | STORE_LE(sb->s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
|
---|
449 | STORE_LE(sb->s_log_block_size, blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE);
|
---|
450 | STORE_LE(sb->s_log_frag_size, blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE);
|
---|
451 | // first 1024 bytes of the device are for boot record. If block size is 1024 bytes, then
|
---|
452 | // the first block is 1, otherwise 0
|
---|
453 | STORE_LE(sb->s_first_data_block, first_block);
|
---|
454 | // block and inode bitmaps occupy no more than one block, so maximum number of blocks is
|
---|
455 | STORE_LE(sb->s_blocks_per_group, blocks_per_group);
|
---|
456 | STORE_LE(sb->s_frags_per_group, blocks_per_group);
|
---|
457 | // blocks
|
---|
458 | STORE_LE(sb->s_blocks_count, nblocks);
|
---|
459 | // reserve blocks for superuser
|
---|
460 | STORE_LE(sb->s_r_blocks_count, nreserved);
|
---|
461 | // ninodes
|
---|
462 | STORE_LE(sb->s_inodes_per_group, inodes_per_group);
|
---|
463 | STORE_LE(sb->s_inodes_count, inodes_per_group * ngroups);
|
---|
464 | STORE_LE(sb->s_free_inodes_count, inodes_per_group * ngroups - EXT2_GOOD_OLD_FIRST_INO);
|
---|
465 | // timestamps
|
---|
466 | timestamp = time(NULL);
|
---|
467 | STORE_LE(sb->s_mkfs_time, timestamp);
|
---|
468 | STORE_LE(sb->s_wtime, timestamp);
|
---|
469 | STORE_LE(sb->s_lastcheck, timestamp);
|
---|
470 | // misc. Values are chosen to match mke2fs 1.41.9
|
---|
471 | STORE_LE(sb->s_state, 1); // TODO: what's 1?
|
---|
472 | STORE_LE(sb->s_creator_os, EXT2_OS_LINUX);
|
---|
473 | STORE_LE(sb->s_checkinterval, 24*60*60 * 180); // 180 days
|
---|
474 | STORE_LE(sb->s_errors, EXT2_ERRORS_DEFAULT);
|
---|
475 | // mke2fs 1.41.9 also sets EXT3_FEATURE_COMPAT_RESIZE_INODE
|
---|
476 | // and if >= 0.5GB, EXT3_FEATURE_RO_COMPAT_LARGE_FILE.
|
---|
477 | // we use values which match "mke2fs -O ^resize_inode":
|
---|
478 | // in this case 1.41.9 never sets EXT3_FEATURE_RO_COMPAT_LARGE_FILE.
|
---|
479 | STORE_LE(sb->s_feature_compat, EXT2_FEATURE_COMPAT_SUPP
|
---|
480 | | (EXT2_FEATURE_COMPAT_RESIZE_INO * ENABLE_FEATURE_MKFS_EXT2_RESERVED_GDT)
|
---|
481 | | (EXT2_FEATURE_COMPAT_DIR_INDEX * ENABLE_FEATURE_MKFS_EXT2_DIR_INDEX)
|
---|
482 | );
|
---|
483 | STORE_LE(sb->s_feature_incompat, EXT2_FEATURE_INCOMPAT_FILETYPE);
|
---|
484 | STORE_LE(sb->s_feature_ro_compat, EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER);
|
---|
485 | STORE_LE(sb->s_flags, EXT2_FLAGS_UNSIGNED_HASH * ENABLE_FEATURE_MKFS_EXT2_DIR_INDEX);
|
---|
486 | generate_uuid(sb->s_uuid);
|
---|
487 | if (ENABLE_FEATURE_MKFS_EXT2_DIR_INDEX) {
|
---|
488 | STORE_LE(sb->s_def_hash_version, EXT2_HASH_HALF_MD4);
|
---|
489 | generate_uuid((uint8_t *)sb->s_hash_seed);
|
---|
490 | }
|
---|
491 | /*
|
---|
492 | * From e2fsprogs: add "jitter" to the superblock's check interval so that we
|
---|
493 | * don't check all the filesystems at the same time. We use a
|
---|
494 | * kludgy hack of using the UUID to derive a random jitter value.
|
---|
495 | */
|
---|
496 | STORE_LE(sb->s_max_mnt_count,
|
---|
497 | EXT2_DFL_MAX_MNT_COUNT
|
---|
498 | + (sb->s_uuid[ARRAY_SIZE(sb->s_uuid)-1] % EXT2_DFL_MAX_MNT_COUNT));
|
---|
499 |
|
---|
500 | // write the label
|
---|
501 | safe_strncpy((char *)sb->s_volume_name, label, sizeof(sb->s_volume_name));
|
---|
502 |
|
---|
503 | // calculate filesystem skeleton structures
|
---|
504 | gd = xzalloc(group_desc_blocks * blocksize);
|
---|
505 | buf = xmalloc(blocksize);
|
---|
506 | sb->s_free_blocks_count = 0;
|
---|
507 | for (i = 0, pos = first_block, n = nblocks - first_block;
|
---|
508 | i < ngroups;
|
---|
509 | i++, pos += blocks_per_group, n -= blocks_per_group
|
---|
510 | ) {
|
---|
511 | uint32_t overhead = pos + (has_super(i) ? (1/*sb*/ + group_desc_blocks) : 0);
|
---|
512 | uint32_t free_blocks;
|
---|
513 | // fill group descriptors
|
---|
514 | STORE_LE(gd[i].bg_block_bitmap, overhead + 0);
|
---|
515 | STORE_LE(gd[i].bg_inode_bitmap, overhead + 1);
|
---|
516 | STORE_LE(gd[i].bg_inode_table, overhead + 2);
|
---|
517 | overhead = overhead - pos + 1/*bbmp*/ + 1/*ibmp*/ + inode_table_blocks;
|
---|
518 | gd[i].bg_free_inodes_count = inodes_per_group;
|
---|
519 | //STORE_LE(gd[i].bg_used_dirs_count, 0);
|
---|
520 | // N.B. both "/" and "/lost+found" are within the first block group
|
---|
521 | // "/" occupies 1 block, "/lost+found" occupies lost_and_found_blocks...
|
---|
522 | if (0 == i) {
|
---|
523 | // ... thus increased overhead for the first block group ...
|
---|
524 | overhead += 1 + lost_and_found_blocks;
|
---|
525 | // ... and 2 used directories
|
---|
526 | STORE_LE(gd[i].bg_used_dirs_count, 2);
|
---|
527 | // well known reserved inodes belong to the first block too
|
---|
528 | gd[i].bg_free_inodes_count -= EXT2_GOOD_OLD_FIRST_INO;
|
---|
529 | }
|
---|
530 |
|
---|
531 | // cache free block count of the group
|
---|
532 | free_blocks = (n < blocks_per_group ? n : blocks_per_group) - overhead;
|
---|
533 |
|
---|
534 | // mark preallocated blocks as allocated
|
---|
535 | //bb_info_msg("ALLOC: [%u][%u][%u]", blocksize, overhead, blocks_per_group - (free_blocks + overhead));
|
---|
536 | allocate(buf, blocksize,
|
---|
537 | // reserve "overhead" blocks
|
---|
538 | overhead,
|
---|
539 | // mark unused trailing blocks
|
---|
540 | blocks_per_group - (free_blocks + overhead)
|
---|
541 | );
|
---|
542 | // dump block bitmap
|
---|
543 | PUT((uint64_t)(FETCH_LE32(gd[i].bg_block_bitmap)) * blocksize, buf, blocksize);
|
---|
544 | STORE_LE(gd[i].bg_free_blocks_count, free_blocks);
|
---|
545 |
|
---|
546 | // mark preallocated inodes as allocated
|
---|
547 | allocate(buf, blocksize,
|
---|
548 | // mark reserved inodes
|
---|
549 | inodes_per_group - gd[i].bg_free_inodes_count,
|
---|
550 | // mark unused trailing inodes
|
---|
551 | blocks_per_group - inodes_per_group
|
---|
552 | );
|
---|
553 | // dump inode bitmap
|
---|
554 | //PUT((uint64_t)(FETCH_LE32(gd[i].bg_block_bitmap)) * blocksize, buf, blocksize);
|
---|
555 | //but it's right after block bitmap, so we can just:
|
---|
556 | xwrite(fd, buf, blocksize);
|
---|
557 | STORE_LE(gd[i].bg_free_inodes_count, gd[i].bg_free_inodes_count);
|
---|
558 |
|
---|
559 | // count overall free blocks
|
---|
560 | sb->s_free_blocks_count += free_blocks;
|
---|
561 | }
|
---|
562 | STORE_LE(sb->s_free_blocks_count, sb->s_free_blocks_count);
|
---|
563 |
|
---|
564 | // dump filesystem skeleton structures
|
---|
565 | // printf("Writing superblocks and filesystem accounting information: ");
|
---|
566 | for (i = 0, pos = first_block; i < ngroups; i++, pos += blocks_per_group) {
|
---|
567 | // dump superblock and group descriptors and their backups
|
---|
568 | if (has_super(i)) {
|
---|
569 | // N.B. 1024 byte blocks are special
|
---|
570 | PUT(((uint64_t)pos * blocksize) + ((0 == i && 1024 != blocksize) ? 1024 : 0),
|
---|
571 | sb, 1024);
|
---|
572 | PUT(((uint64_t)pos * blocksize) + blocksize,
|
---|
573 | gd, group_desc_blocks * blocksize);
|
---|
574 | }
|
---|
575 | }
|
---|
576 |
|
---|
577 | // zero boot sectors
|
---|
578 | memset(buf, 0, blocksize);
|
---|
579 | PUT(0, buf, 1024); // N.B. 1024 <= blocksize, so buf[0..1023] contains zeros
|
---|
580 | // zero inode tables
|
---|
581 | for (i = 0; i < ngroups; ++i)
|
---|
582 | for (n = 0; n < inode_table_blocks; ++n)
|
---|
583 | PUT((uint64_t)(FETCH_LE32(gd[i].bg_inode_table) + n) * blocksize,
|
---|
584 | buf, blocksize);
|
---|
585 |
|
---|
586 | // prepare directory inode
|
---|
587 | inode = (struct ext2_inode *)buf;
|
---|
588 | STORE_LE(inode->i_mode, S_IFDIR | S_IRWXU | S_IRGRP | S_IROTH | S_IXGRP | S_IXOTH);
|
---|
589 | STORE_LE(inode->i_mtime, timestamp);
|
---|
590 | STORE_LE(inode->i_atime, timestamp);
|
---|
591 | STORE_LE(inode->i_ctime, timestamp);
|
---|
592 | STORE_LE(inode->i_size, blocksize);
|
---|
593 | // inode->i_blocks stores the number of 512 byte data blocks
|
---|
594 | // (512, because it goes directly to struct stat without scaling)
|
---|
595 | STORE_LE(inode->i_blocks, blocksize / 512);
|
---|
596 |
|
---|
597 | // dump root dir inode
|
---|
598 | STORE_LE(inode->i_links_count, 3); // "/.", "/..", "/lost+found/.." point to this inode
|
---|
599 | STORE_LE(inode->i_block[0], FETCH_LE32(gd[0].bg_inode_table) + inode_table_blocks);
|
---|
600 | PUT(((uint64_t)FETCH_LE32(gd[0].bg_inode_table) * blocksize) + (EXT2_ROOT_INO-1) * inodesize,
|
---|
601 | buf, inodesize);
|
---|
602 |
|
---|
603 | // dump lost+found dir inode
|
---|
604 | STORE_LE(inode->i_links_count, 2); // both "/lost+found" and "/lost+found/." point to this inode
|
---|
605 | STORE_LE(inode->i_size, lost_and_found_blocks * blocksize);
|
---|
606 | STORE_LE(inode->i_blocks, (lost_and_found_blocks * blocksize) / 512);
|
---|
607 | n = FETCH_LE32(inode->i_block[0]) + 1;
|
---|
608 | for (i = 0; i < lost_and_found_blocks; ++i)
|
---|
609 | STORE_LE(inode->i_block[i], i + n); // use next block
|
---|
610 | //bb_info_msg("LAST BLOCK USED[%u]", i + n);
|
---|
611 | PUT(((uint64_t)FETCH_LE32(gd[0].bg_inode_table) * blocksize) + (EXT2_GOOD_OLD_FIRST_INO-1) * inodesize,
|
---|
612 | buf, inodesize);
|
---|
613 |
|
---|
614 | // dump directories
|
---|
615 | memset(buf, 0, blocksize);
|
---|
616 | dir = (struct ext2_dir *)buf;
|
---|
617 |
|
---|
618 | // dump 2nd+ blocks of "/lost+found"
|
---|
619 | STORE_LE(dir->rec_len1, blocksize); // e2fsck 1.41.4 compat (1.41.9 does not need this)
|
---|
620 | for (i = 1; i < lost_and_found_blocks; ++i)
|
---|
621 | PUT((uint64_t)(FETCH_LE32(gd[0].bg_inode_table) + inode_table_blocks + 1+i) * blocksize,
|
---|
622 | buf, blocksize);
|
---|
623 |
|
---|
624 | // dump 1st block of "/lost+found"
|
---|
625 | STORE_LE(dir->inode1, EXT2_GOOD_OLD_FIRST_INO);
|
---|
626 | STORE_LE(dir->rec_len1, 12);
|
---|
627 | STORE_LE(dir->name_len1, 1);
|
---|
628 | STORE_LE(dir->file_type1, EXT2_FT_DIR);
|
---|
629 | dir->name1[0] = '.';
|
---|
630 | STORE_LE(dir->inode2, EXT2_ROOT_INO);
|
---|
631 | STORE_LE(dir->rec_len2, blocksize - 12);
|
---|
632 | STORE_LE(dir->name_len2, 2);
|
---|
633 | STORE_LE(dir->file_type2, EXT2_FT_DIR);
|
---|
634 | dir->name2[0] = '.'; dir->name2[1] = '.';
|
---|
635 | PUT((uint64_t)(FETCH_LE32(gd[0].bg_inode_table) + inode_table_blocks + 1) * blocksize, buf, blocksize);
|
---|
636 |
|
---|
637 | // dump root dir block
|
---|
638 | STORE_LE(dir->inode1, EXT2_ROOT_INO);
|
---|
639 | STORE_LE(dir->rec_len2, 12);
|
---|
640 | STORE_LE(dir->inode3, EXT2_GOOD_OLD_FIRST_INO);
|
---|
641 | STORE_LE(dir->rec_len3, blocksize - 12 - 12);
|
---|
642 | STORE_LE(dir->name_len3, 10);
|
---|
643 | STORE_LE(dir->file_type3, EXT2_FT_DIR);
|
---|
644 | strcpy(dir->name3, "lost+found");
|
---|
645 | PUT((uint64_t)(FETCH_LE32(gd[0].bg_inode_table) + inode_table_blocks + 0) * blocksize, buf, blocksize);
|
---|
646 |
|
---|
647 | // cleanup
|
---|
648 | if (ENABLE_FEATURE_CLEAN_UP) {
|
---|
649 | free(buf);
|
---|
650 | free(gd);
|
---|
651 | free(sb);
|
---|
652 | }
|
---|
653 |
|
---|
654 | xclose(fd);
|
---|
655 | return EXIT_SUCCESS;
|
---|
656 | }
|
---|