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| author | Denys Vlasenko <vda.linux@googlemail.com> | 2009-10-21 11:34:32 +0200 |
|---|---|---|
| committer | Denys Vlasenko <vda.linux@googlemail.com> | 2009-10-21 11:34:32 +0200 |
| commit | 2ee2724a41f195f8a5e3e4e9ebc54dadc255d6f7 (patch) | |
| tree | b3b973095c4b77b0ff48a3c113138ca747d1f4fc /util-linux/mkfs_ext2.c | |
| parent | 2288d86a54eee81800bdadea6f603ad4e234efb1 (diff) | |
| download | busybox-w32-2ee2724a41f195f8a5e3e4e9ebc54dadc255d6f7.tar.gz busybox-w32-2ee2724a41f195f8a5e3e4e9ebc54dadc255d6f7.tar.bz2 busybox-w32-2ee2724a41f195f8a5e3e4e9ebc54dadc255d6f7.zip | |
mkfs_ext2: explain 256-byte inodes. no code changes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'util-linux/mkfs_ext2.c')
| -rw-r--r-- | util-linux/mkfs_ext2.c | 58 |
1 files changed, 39 insertions, 19 deletions
diff --git a/util-linux/mkfs_ext2.c b/util-linux/mkfs_ext2.c index de4c8b6c6..5cd923811 100644 --- a/util-linux/mkfs_ext2.c +++ b/util-linux/mkfs_ext2.c | |||
| @@ -120,16 +120,45 @@ static uint32_t has_super(uint32_t x) | |||
| 120 | } | 120 | } |
| 121 | } | 121 | } |
| 122 | 122 | ||
| 123 | /* Standard mke2fs 1.41.9: | 123 | #define fd 3 /* predefined output descriptor */ |
| 124 | * Usage: mke2fs [-c|-l filename] [-b block-size] [-f fragment-size] | 124 | |
| 125 | * [-i bytes-per-inode] [-I inode-size] [-J journal-options] | 125 | static void PUT(uint64_t off, void *buf, uint32_t size) |
| 126 | * [-G meta group size] [-N number-of-inodes] | 126 | { |
| 127 | * [-m reserved-blocks-percentage] [-o creator-os] | 127 | // bb_info_msg("PUT[%llu]:[%u]", off, size); |
| 128 | * [-g blocks-per-group] [-L volume-label] [-M last-mounted-directory] | 128 | xlseek(fd, off, SEEK_SET); |
| 129 | * [-O feature[,...]] [-r fs-revision] [-E extended-option[,...]] | 129 | xwrite(fd, buf, size); |
| 130 | * [-T fs-type] [-U UUID] [-jnqvFSV] device [blocks-count] | 130 | } |
| 131 | */ | 131 | |
| 132 | // N.B. not commented below options are taken and silently ignored | 132 | // 128 and 256-byte inodes: |
| 133 | // 128-byte inode is described by struct ext2_inode. | ||
| 134 | // 256-byte one just has these fields appended: | ||
| 135 | // __u16 i_extra_isize; | ||
| 136 | // __u16 i_pad1; | ||
| 137 | // __u32 i_ctime_extra; /* extra Change time (nsec << 2 | epoch) */ | ||
| 138 | // __u32 i_mtime_extra; /* extra Modification time (nsec << 2 | epoch) */ | ||
| 139 | // __u32 i_atime_extra; /* extra Access time (nsec << 2 | epoch) */ | ||
| 140 | // __u32 i_crtime; /* File creation time */ | ||
| 141 | // __u32 i_crtime_extra; /* extra File creation time (nsec << 2 | epoch)*/ | ||
| 142 | // __u32 i_version_hi; /* high 32 bits for 64-bit version */ | ||
| 143 | // the rest is padding. | ||
| 144 | // | ||
| 145 | // linux/ext2_fs.h has "#define i_size_high i_dir_acl" which suggests that even | ||
| 146 | // 128-byte inode is capable of describing large files (i_dir_acl is meaningful | ||
| 147 | // only for directories, which never need i_size_high). | ||
| 148 | // | ||
| 149 | // Standard mke2fs creates a filesystem with 256-byte inodes if it is | ||
| 150 | // bigger than 0.5GB. So far, we do not do this. | ||
| 151 | |||
| 152 | // Standard mke2fs 1.41.9: | ||
| 153 | // Usage: mke2fs [-c|-l filename] [-b block-size] [-f fragment-size] | ||
| 154 | // [-i bytes-per-inode] [-I inode-size] [-J journal-options] | ||
| 155 | // [-G meta group size] [-N number-of-inodes] | ||
| 156 | // [-m reserved-blocks-percentage] [-o creator-os] | ||
| 157 | // [-g blocks-per-group] [-L volume-label] [-M last-mounted-directory] | ||
| 158 | // [-O feature[,...]] [-r fs-revision] [-E extended-option[,...]] | ||
| 159 | // [-T fs-type] [-U UUID] [-jnqvFSV] device [blocks-count] | ||
| 160 | // | ||
| 161 | // Options not commented below are taken but silently ignored: | ||
| 133 | enum { | 162 | enum { |
| 134 | OPT_c = 1 << 0, | 163 | OPT_c = 1 << 0, |
| 135 | OPT_l = 1 << 1, | 164 | OPT_l = 1 << 1, |
| @@ -159,15 +188,6 @@ enum { | |||
| 159 | //OPT_V = 1 << 25, // -V version. bbox applets don't support that | 188 | //OPT_V = 1 << 25, // -V version. bbox applets don't support that |
| 160 | }; | 189 | }; |
| 161 | 190 | ||
| 162 | #define fd 3 /* predefined output descriptor */ | ||
| 163 | |||
| 164 | static void PUT(uint64_t off, void *buf, uint32_t size) | ||
| 165 | { | ||
| 166 | // bb_info_msg("PUT[%llu]:[%u]", off, size); | ||
| 167 | xlseek(fd, off, SEEK_SET); | ||
| 168 | xwrite(fd, buf, size); | ||
| 169 | } | ||
| 170 | |||
| 171 | int mkfs_ext2_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; | 191 | int mkfs_ext2_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| 172 | int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv) | 192 | int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv) |
| 173 | { | 193 | { |