| /* vi: set sw=4 ts=4: */ |
| /* |
| * mkfs_ext2: utility to create EXT2 filesystem |
| * inspired by genext2fs |
| * |
| * Busybox'ed (2009) by Vladimir Dronnikov <dronnikov@gmail.com> |
| * |
| * Licensed under GPLv2, see file LICENSE in this source tree. |
| */ |
| #include "libbb.h" |
| #include <linux/fs.h> |
| #include <linux/ext2_fs.h> |
| |
| #define ENABLE_FEATURE_MKFS_EXT2_RESERVED_GDT 0 |
| #define ENABLE_FEATURE_MKFS_EXT2_DIR_INDEX 1 |
| |
| // from e2fsprogs |
| #define s_reserved_gdt_blocks s_padding1 |
| #define s_mkfs_time s_reserved[0] |
| #define s_flags s_reserved[22] |
| |
| #define EXT2_HASH_HALF_MD4 1 |
| #define EXT2_FLAGS_SIGNED_HASH 0x0001 |
| #define EXT2_FLAGS_UNSIGNED_HASH 0x0002 |
| |
| // storage helpers |
| char BUG_wrong_field_size(void); |
| #define STORE_LE(field, value) \ |
| do { \ |
| if (sizeof(field) == 4) \ |
| field = SWAP_LE32(value); \ |
| else if (sizeof(field) == 2) \ |
| field = SWAP_LE16(value); \ |
| else if (sizeof(field) == 1) \ |
| field = (value); \ |
| else \ |
| BUG_wrong_field_size(); \ |
| } while (0) |
| |
| #define FETCH_LE32(field) \ |
| (sizeof(field) == 4 ? SWAP_LE32(field) : BUG_wrong_field_size()) |
| |
| // All fields are little-endian |
| struct ext2_dir { |
| uint32_t inode1; |
| uint16_t rec_len1; |
| uint8_t name_len1; |
| uint8_t file_type1; |
| char name1[4]; |
| uint32_t inode2; |
| uint16_t rec_len2; |
| uint8_t name_len2; |
| uint8_t file_type2; |
| char name2[4]; |
| uint32_t inode3; |
| uint16_t rec_len3; |
| uint8_t name_len3; |
| uint8_t file_type3; |
| char name3[12]; |
| }; |
| |
| static unsigned int_log2(unsigned arg) |
| { |
| unsigned r = 0; |
| while ((arg >>= 1) != 0) |
| r++; |
| return r; |
| } |
| |
| // taken from mkfs_minix.c. libbb candidate? |
| // "uint32_t size", since we never use it for anything >32 bits |
| static uint32_t div_roundup(uint32_t size, uint32_t n) |
| { |
| // Overflow-resistant |
| uint32_t res = size / n; |
| if (res * n != size) |
| res++; |
| return res; |
| } |
| |
| static void allocate(uint8_t *bitmap, uint32_t blocksize, uint32_t start, uint32_t end) |
| { |
| uint32_t i; |
| |
| //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))); |
| memset(bitmap, 0, blocksize); |
| i = start / 8; |
| memset(bitmap, 0xFF, i); |
| bitmap[i] = (1 << (start & 7)) - 1; //0..7 => 00000000..01111111 |
| i = end / 8; |
| bitmap[blocksize - i - 1] |= 0x7F00 >> (end & 7); //0..7 => 00000000..11111110 |
| memset(bitmap + blocksize - i, 0xFF, i); // N.B. no overflow here! |
| } |
| |
| static uint32_t has_super(uint32_t x) |
| { |
| // 0, 1 and powers of 3, 5, 7 up to 2^32 limit |
| static const uint32_t supers[] = { |
| 0, 1, 3, 5, 7, 9, 25, 27, 49, 81, 125, 243, 343, 625, 729, |
| 2187, 2401, 3125, 6561, 15625, 16807, 19683, 59049, 78125, |
| 117649, 177147, 390625, 531441, 823543, 1594323, 1953125, |
| 4782969, 5764801, 9765625, 14348907, 40353607, 43046721, |
| 48828125, 129140163, 244140625, 282475249, 387420489, |
| 1162261467, 1220703125, 1977326743, 3486784401/* >2^31 */, |
| }; |
| const uint32_t *sp = supers + ARRAY_SIZE(supers); |
| while (1) { |
| sp--; |
| if (x == *sp) |
| return 1; |
| if (x > *sp) |
| return 0; |
| } |
| } |
| |
| #define fd 3 /* predefined output descriptor */ |
| |
| static void PUT(uint64_t off, void *buf, uint32_t size) |
| { |
| // bb_info_msg("PUT[%llu]:[%u]", off, size); |
| xlseek(fd, off, SEEK_SET); |
| xwrite(fd, buf, size); |
| } |
| |
| // 128 and 256-byte inodes: |
| // 128-byte inode is described by struct ext2_inode. |
| // 256-byte one just has these fields appended: |
| // __u16 i_extra_isize; |
| // __u16 i_pad1; |
| // __u32 i_ctime_extra; /* extra Change time (nsec << 2 | epoch) */ |
| // __u32 i_mtime_extra; /* extra Modification time (nsec << 2 | epoch) */ |
| // __u32 i_atime_extra; /* extra Access time (nsec << 2 | epoch) */ |
| // __u32 i_crtime; /* File creation time */ |
| // __u32 i_crtime_extra; /* extra File creation time (nsec << 2 | epoch)*/ |
| // __u32 i_version_hi; /* high 32 bits for 64-bit version */ |
| // the rest is padding. |
| // |
| // linux/ext2_fs.h has "#define i_size_high i_dir_acl" which suggests that even |
| // 128-byte inode is capable of describing large files (i_dir_acl is meaningful |
| // only for directories, which never need i_size_high). |
| // |
| // Standard mke2fs creates a filesystem with 256-byte inodes if it is |
| // bigger than 0.5GB. |
| |
| // Standard mke2fs 1.41.9: |
| // Usage: mke2fs [-c|-l filename] [-b block-size] [-f fragment-size] |
| // [-i bytes-per-inode] [-I inode-size] [-J journal-options] |
| // [-G meta group size] [-N number-of-inodes] |
| // [-m reserved-blocks-percentage] [-o creator-os] |
| // [-g blocks-per-group] [-L volume-label] [-M last-mounted-directory] |
| // [-O feature[,...]] [-r fs-revision] [-E extended-option[,...]] |
| // [-T fs-type] [-U UUID] [-jnqvFSV] device [blocks-count] |
| // |
| // Options not commented below are taken but silently ignored: |
| enum { |
| OPT_c = 1 << 0, |
| OPT_l = 1 << 1, |
| OPT_b = 1 << 2, // block size, in bytes |
| OPT_f = 1 << 3, |
| OPT_i = 1 << 4, // bytes per inode |
| OPT_I = 1 << 5, // custom inode size, in bytes |
| OPT_J = 1 << 6, |
| OPT_G = 1 << 7, |
| OPT_N = 1 << 8, |
| OPT_m = 1 << 9, // percentage of blocks reserved for superuser |
| OPT_o = 1 << 10, |
| OPT_g = 1 << 11, |
| OPT_L = 1 << 12, // label |
| OPT_M = 1 << 13, |
| OPT_O = 1 << 14, |
| OPT_r = 1 << 15, |
| OPT_E = 1 << 16, |
| OPT_T = 1 << 17, |
| OPT_U = 1 << 18, |
| OPT_j = 1 << 19, |
| OPT_n = 1 << 20, // dry run: do not write anything |
| OPT_q = 1 << 21, |
| OPT_v = 1 << 22, |
| OPT_F = 1 << 23, |
| OPT_S = 1 << 24, |
| //OPT_V = 1 << 25, // -V version. bbox applets don't support that |
| }; |
| |
| int mkfs_ext2_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv) |
| { |
| unsigned i, pos, n; |
| unsigned bs, bpi; |
| unsigned blocksize, blocksize_log2; |
| unsigned inodesize, user_inodesize; |
| unsigned reserved_percent = 5; |
| unsigned long long kilobytes; |
| uint32_t nblocks, nblocks_full; |
| uint32_t nreserved; |
| uint32_t ngroups; |
| uint32_t bytes_per_inode; |
| uint32_t first_block; |
| uint32_t inodes_per_group; |
| uint32_t group_desc_blocks; |
| uint32_t inode_table_blocks; |
| uint32_t lost_and_found_blocks; |
| time_t timestamp; |
| const char *label = ""; |
| struct stat st; |
| struct ext2_super_block *sb; // superblock |
| struct ext2_group_desc *gd; // group descriptors |
| struct ext2_inode *inode; |
| struct ext2_dir *dir; |
| uint8_t *buf; |
| |
| // using global "option_mask32" instead of local "opts": |
| // we are register starved here |
| opt_complementary = "-1:b+:i+:I+:m+"; |
| /*opts =*/ getopt32(argv, "cl:b:f:i:I:J:G:N:m:o:g:L:M:O:r:E:T:U:jnqvFS", |
| /*lbfi:*/ NULL, &bs, NULL, &bpi, |
| /*IJGN:*/ &user_inodesize, NULL, NULL, NULL, |
| /*mogL:*/ &reserved_percent, NULL, NULL, &label, |
| /*MOrE:*/ NULL, NULL, NULL, NULL, |
| /*TU:*/ NULL, NULL); |
| argv += optind; // argv[0] -- device |
| |
| // open the device, check the device is a block device |
| xmove_fd(xopen(argv[0], O_WRONLY), fd); |
| xfstat(fd, &st, argv[0]); |
| if (!S_ISBLK(st.st_mode) && !(option_mask32 & OPT_F)) |
| bb_error_msg_and_die("%s: not a block device", argv[0]); |
| |
| // check if it is mounted |
| // N.B. what if we format a file? find_mount_point will return false negative since |
| // it is loop block device which is mounted! |
| if (find_mount_point(argv[0], 0)) |
| bb_error_msg_and_die("can't format mounted filesystem"); |
| |
| // get size in kbytes |
| kilobytes = get_volume_size_in_bytes(fd, argv[1], 1024, /*extend:*/ !(option_mask32 & OPT_n)) / 1024; |
| |
| bytes_per_inode = 16384; |
| if (kilobytes < 512*1024) |
| bytes_per_inode = 4096; |
| if (kilobytes < 3*1024) |
| bytes_per_inode = 8192; |
| if (option_mask32 & OPT_i) |
| bytes_per_inode = bpi; |
| |
| // Determine block size and inode size |
| // block size is a multiple of 1024 |
| // inode size is a multiple of 128 |
| blocksize = 1024; |
| inodesize = sizeof(struct ext2_inode); // 128 |
| if (kilobytes >= 512*1024) { // mke2fs 1.41.9 compat |
| blocksize = 4096; |
| inodesize = 256; |
| } |
| if (EXT2_MAX_BLOCK_SIZE > 4096) { |
| // kilobytes >> 22 == size in 4gigabyte chunks. |
| // if size >= 16k gigs, blocksize must be increased. |
| // Try "mke2fs -F image $((16 * 1024*1024*1024))" |
| while ((kilobytes >> 22) >= blocksize) |
| blocksize *= 2; |
| } |
| if (option_mask32 & OPT_b) |
| blocksize = bs; |
| if (blocksize < EXT2_MIN_BLOCK_SIZE |
| || blocksize > EXT2_MAX_BLOCK_SIZE |
| || (blocksize & (blocksize - 1)) // not power of 2 |
| ) { |
| bb_error_msg_and_die("blocksize %u is bad", blocksize); |
| } |
| // Do we have custom inode size? |
| if (option_mask32 & OPT_I) { |
| if (user_inodesize < sizeof(*inode) |
| || user_inodesize > blocksize |
| || (user_inodesize & (user_inodesize - 1)) // not power of 2 |
| ) { |
| bb_error_msg("-%c is bad", 'I'); |
| } else { |
| inodesize = user_inodesize; |
| } |
| } |
| |
| if ((int32_t)bytes_per_inode < blocksize) |
| bb_error_msg_and_die("-%c is bad", 'i'); |
| // number of bits in one block, i.e. 8*blocksize |
| #define blocks_per_group (8 * blocksize) |
| first_block = (EXT2_MIN_BLOCK_SIZE == blocksize); |
| blocksize_log2 = int_log2(blocksize); |
| |
| // Determine number of blocks |
| kilobytes >>= (blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE); |
| nblocks = kilobytes; |
| if (nblocks != kilobytes) |
| bb_error_msg_and_die("block count doesn't fit in 32 bits"); |
| #define kilobytes kilobytes_unused_after_this |
| // Experimentally, standard mke2fs won't work on images smaller than 60k |
| if (nblocks < 60) |
| bb_error_msg_and_die("need >= 60 blocks"); |
| |
| // How many reserved blocks? |
| if (reserved_percent > 50) |
| bb_error_msg_and_die("-%c is bad", 'm'); |
| nreserved = (uint64_t)nblocks * reserved_percent / 100; |
| |
| // N.B. killing e2fsprogs feature! Unused blocks don't account in calculations |
| nblocks_full = nblocks; |
| |
| // If last block group is too small, nblocks may be decreased in order |
| // to discard it, and control returns here to recalculate some |
| // parameters. |
| // Note: blocksize and bytes_per_inode are never recalculated. |
| retry: |
| // N.B. a block group can have no more than blocks_per_group blocks |
| ngroups = div_roundup(nblocks - first_block, blocks_per_group); |
| |
| group_desc_blocks = div_roundup(ngroups, blocksize / sizeof(*gd)); |
| // TODO: reserved blocks must be marked as such in the bitmaps, |
| // or resulting filesystem is corrupt |
| if (ENABLE_FEATURE_MKFS_EXT2_RESERVED_GDT) { |
| /* |
| * From e2fsprogs: Calculate the number of GDT blocks to reserve for online |
| * filesystem growth. |
| * The absolute maximum number of GDT blocks we can reserve is determined by |
| * the number of block pointers that can fit into a single block. |
| * We set it at 1024x the current filesystem size, or |
| * the upper block count limit (2^32), whichever is lower. |
| */ |
| uint32_t reserved_group_desc_blocks = 0xFFFFFFFF; // maximum block number |
| if (nblocks < reserved_group_desc_blocks / 1024) |
| reserved_group_desc_blocks = nblocks * 1024; |
| reserved_group_desc_blocks = div_roundup(reserved_group_desc_blocks - first_block, blocks_per_group); |
| reserved_group_desc_blocks = div_roundup(reserved_group_desc_blocks, blocksize / sizeof(*gd)) - group_desc_blocks; |
| if (reserved_group_desc_blocks > blocksize / sizeof(uint32_t)) |
| reserved_group_desc_blocks = blocksize / sizeof(uint32_t); |
| //TODO: STORE_LE(sb->s_reserved_gdt_blocks, reserved_group_desc_blocks); |
| group_desc_blocks += reserved_group_desc_blocks; |
| } |
| |
| { |
| // N.B. e2fsprogs does as follows! |
| uint32_t overhead, remainder; |
| // ninodes is the max number of inodes in this filesystem |
| uint32_t ninodes = ((uint64_t) nblocks_full * blocksize) / bytes_per_inode; |
| if (ninodes < EXT2_GOOD_OLD_FIRST_INO+1) |
| ninodes = EXT2_GOOD_OLD_FIRST_INO+1; |
| inodes_per_group = div_roundup(ninodes, ngroups); |
| // minimum number because the first EXT2_GOOD_OLD_FIRST_INO-1 are reserved |
| if (inodes_per_group < 16) |
| inodes_per_group = 16; |
| // a block group can't have more inodes than blocks |
| if (inodes_per_group > blocks_per_group) |
| inodes_per_group = blocks_per_group; |
| // adjust inodes per group so they completely fill the inode table blocks in the descriptor |
| inodes_per_group = (div_roundup(inodes_per_group * inodesize, blocksize) * blocksize) / inodesize; |
| // make sure the number of inodes per group is a multiple of 8 |
| inodes_per_group &= ~7; |
| inode_table_blocks = div_roundup(inodes_per_group * inodesize, blocksize); |
| |
| // to be useful, lost+found should occupy at least 2 blocks (but not exceeding 16*1024 bytes), |
| // and at most EXT2_NDIR_BLOCKS. So reserve these blocks right now |
| /* Or e2fsprogs comment verbatim (what does it mean?): |
| * Ensure that lost+found is at least 2 blocks, so we always |
| * test large empty blocks for big-block filesystems. */ |
| lost_and_found_blocks = MIN(EXT2_NDIR_BLOCKS, 16 >> (blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE)); |
| |
| // the last group needs more attention: isn't it too small for possible overhead? |
| overhead = (has_super(ngroups - 1) ? (1/*sb*/ + group_desc_blocks) : 0) + 1/*bbmp*/ + 1/*ibmp*/ + inode_table_blocks; |
| remainder = (nblocks - first_block) % blocks_per_group; |
| ////can't happen, nblocks >= 60 guarantees this |
| ////if ((1 == ngroups) |
| //// && remainder |
| //// && (remainder < overhead + 1/* "/" */ + lost_and_found_blocks) |
| ////) { |
| //// bb_error_msg_and_die("way small device"); |
| ////} |
| |
| // Standard mke2fs uses 50. Looks like a bug in our calculation |
| // of "remainder" or "overhead" - we don't match standard mke2fs |
| // when we transition from one group to two groups |
| // (a bit after 8M image size), but it works for two->three groups |
| // transition (at 16M). |
| if (remainder && (remainder < overhead + 50)) { |
| //bb_info_msg("CHOP[%u]", remainder); |
| nblocks -= remainder; |
| goto retry; |
| } |
| } |
| |
| if (nblocks_full - nblocks) |
| printf("warning: %u blocks unused\n\n", nblocks_full - nblocks); |
| printf( |
| "Filesystem label=%s\n" |
| "OS type: Linux\n" |
| "Block size=%u (log=%u)\n" |
| "Fragment size=%u (log=%u)\n" |
| "%u inodes, %u blocks\n" |
| "%u blocks (%u%%) reserved for the super user\n" |
| "First data block=%u\n" |
| "Maximum filesystem blocks=%u\n" |
| "%u block groups\n" |
| "%u blocks per group, %u fragments per group\n" |
| "%u inodes per group" |
| , label |
| , blocksize, blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE |
| , blocksize, blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE |
| , inodes_per_group * ngroups, nblocks |
| , nreserved, reserved_percent |
| , first_block |
| , group_desc_blocks * (blocksize / (unsigned)sizeof(*gd)) * blocks_per_group |
| , ngroups |
| , blocks_per_group, blocks_per_group |
| , inodes_per_group |
| ); |
| { |
| const char *fmt = "\nSuperblock backups stored on blocks:\n" |
| "\t%u"; |
| pos = first_block; |
| for (i = 1; i < ngroups; i++) { |
| pos += blocks_per_group; |
| if (has_super(i)) { |
| printf(fmt, (unsigned)pos); |
| fmt = ", %u"; |
| } |
| } |
| } |
| bb_putchar('\n'); |
| |
| if (option_mask32 & OPT_n) { |
| if (ENABLE_FEATURE_CLEAN_UP) |
| close(fd); |
| return EXIT_SUCCESS; |
| } |
| |
| // TODO: 3/5 refuse if mounted |
| // TODO: 4/5 compat options |
| // TODO: 1/5 sanity checks |
| // TODO: 0/5 more verbose error messages |
| // TODO: 4/5 bigendianness: recheck, wait for ARM reporters |
| // TODO: 2/5 reserved GDT: how to mark but not allocate? |
| // TODO: 3/5 dir_index? |
| |
| // fill the superblock |
| sb = xzalloc(1024); |
| STORE_LE(sb->s_rev_level, EXT2_DYNAMIC_REV); // revision 1 filesystem |
| STORE_LE(sb->s_magic, EXT2_SUPER_MAGIC); |
| STORE_LE(sb->s_inode_size, inodesize); |
| // set "Required extra isize" and "Desired extra isize" fields to 28 |
| if (inodesize != sizeof(*inode)) |
| STORE_LE(sb->s_reserved[21], 0x001C001C); |
| STORE_LE(sb->s_first_ino, EXT2_GOOD_OLD_FIRST_INO); |
| STORE_LE(sb->s_log_block_size, blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE); |
| STORE_LE(sb->s_log_frag_size, blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE); |
| // first 1024 bytes of the device are for boot record. If block size is 1024 bytes, then |
| // the first block is 1, otherwise 0 |
| STORE_LE(sb->s_first_data_block, first_block); |
| // block and inode bitmaps occupy no more than one block, so maximum number of blocks is |
| STORE_LE(sb->s_blocks_per_group, blocks_per_group); |
| STORE_LE(sb->s_frags_per_group, blocks_per_group); |
| // blocks |
| STORE_LE(sb->s_blocks_count, nblocks); |
| // reserve blocks for superuser |
| STORE_LE(sb->s_r_blocks_count, nreserved); |
| // ninodes |
| STORE_LE(sb->s_inodes_per_group, inodes_per_group); |
| STORE_LE(sb->s_inodes_count, inodes_per_group * ngroups); |
| STORE_LE(sb->s_free_inodes_count, inodes_per_group * ngroups - EXT2_GOOD_OLD_FIRST_INO); |
| // timestamps |
| timestamp = time(NULL); |
| STORE_LE(sb->s_mkfs_time, timestamp); |
| STORE_LE(sb->s_wtime, timestamp); |
| STORE_LE(sb->s_lastcheck, timestamp); |
| // misc. Values are chosen to match mke2fs 1.41.9 |
| STORE_LE(sb->s_state, 1); // TODO: what's 1? |
| STORE_LE(sb->s_creator_os, EXT2_OS_LINUX); |
| STORE_LE(sb->s_checkinterval, 24*60*60 * 180); // 180 days |
| STORE_LE(sb->s_errors, EXT2_ERRORS_DEFAULT); |
| // mke2fs 1.41.9 also sets EXT3_FEATURE_COMPAT_RESIZE_INODE |
| // and if >= 0.5GB, EXT3_FEATURE_RO_COMPAT_LARGE_FILE. |
| // we use values which match "mke2fs -O ^resize_inode": |
| // in this case 1.41.9 never sets EXT3_FEATURE_RO_COMPAT_LARGE_FILE. |
| STORE_LE(sb->s_feature_compat, EXT2_FEATURE_COMPAT_SUPP |
| | (EXT2_FEATURE_COMPAT_RESIZE_INO * ENABLE_FEATURE_MKFS_EXT2_RESERVED_GDT) |
| | (EXT2_FEATURE_COMPAT_DIR_INDEX * ENABLE_FEATURE_MKFS_EXT2_DIR_INDEX) |
| ); |
| STORE_LE(sb->s_feature_incompat, EXT2_FEATURE_INCOMPAT_FILETYPE); |
| STORE_LE(sb->s_feature_ro_compat, EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER); |
| STORE_LE(sb->s_flags, EXT2_FLAGS_UNSIGNED_HASH * ENABLE_FEATURE_MKFS_EXT2_DIR_INDEX); |
| generate_uuid(sb->s_uuid); |
| if (ENABLE_FEATURE_MKFS_EXT2_DIR_INDEX) { |
| STORE_LE(sb->s_def_hash_version, EXT2_HASH_HALF_MD4); |
| generate_uuid((uint8_t *)sb->s_hash_seed); |
| } |
| /* |
| * From e2fsprogs: add "jitter" to the superblock's check interval so that we |
| * don't check all the filesystems at the same time. We use a |
| * kludgy hack of using the UUID to derive a random jitter value. |
| */ |
| STORE_LE(sb->s_max_mnt_count, |
| EXT2_DFL_MAX_MNT_COUNT |
| + (sb->s_uuid[ARRAY_SIZE(sb->s_uuid)-1] % EXT2_DFL_MAX_MNT_COUNT)); |
| |
| // write the label |
| safe_strncpy((char *)sb->s_volume_name, label, sizeof(sb->s_volume_name)); |
| |
| // calculate filesystem skeleton structures |
| gd = xzalloc(group_desc_blocks * blocksize); |
| buf = xmalloc(blocksize); |
| sb->s_free_blocks_count = 0; |
| for (i = 0, pos = first_block, n = nblocks - first_block; |
| i < ngroups; |
| i++, pos += blocks_per_group, n -= blocks_per_group |
| ) { |
| uint32_t overhead = pos + (has_super(i) ? (1/*sb*/ + group_desc_blocks) : 0); |
| uint32_t free_blocks; |
| // fill group descriptors |
| STORE_LE(gd[i].bg_block_bitmap, overhead + 0); |
| STORE_LE(gd[i].bg_inode_bitmap, overhead + 1); |
| STORE_LE(gd[i].bg_inode_table, overhead + 2); |
| overhead = overhead - pos + 1/*bbmp*/ + 1/*ibmp*/ + inode_table_blocks; |
| gd[i].bg_free_inodes_count = inodes_per_group; |
| //STORE_LE(gd[i].bg_used_dirs_count, 0); |
| // N.B. both "/" and "/lost+found" are within the first block group |
| // "/" occupies 1 block, "/lost+found" occupies lost_and_found_blocks... |
| if (0 == i) { |
| // ... thus increased overhead for the first block group ... |
| overhead += 1 + lost_and_found_blocks; |
| // ... and 2 used directories |
| STORE_LE(gd[i].bg_used_dirs_count, 2); |
| // well known reserved inodes belong to the first block too |
| gd[i].bg_free_inodes_count -= EXT2_GOOD_OLD_FIRST_INO; |
| } |
| |
| // cache free block count of the group |
| free_blocks = (n < blocks_per_group ? n : blocks_per_group) - overhead; |
| |
| // mark preallocated blocks as allocated |
| //bb_info_msg("ALLOC: [%u][%u][%u]", blocksize, overhead, blocks_per_group - (free_blocks + overhead)); |
| allocate(buf, blocksize, |
| // reserve "overhead" blocks |
| overhead, |
| // mark unused trailing blocks |
| blocks_per_group - (free_blocks + overhead) |
| ); |
| // dump block bitmap |
| PUT((uint64_t)(FETCH_LE32(gd[i].bg_block_bitmap)) * blocksize, buf, blocksize); |
| STORE_LE(gd[i].bg_free_blocks_count, free_blocks); |
| |
| // mark preallocated inodes as allocated |
| allocate(buf, blocksize, |
| // mark reserved inodes |
| inodes_per_group - gd[i].bg_free_inodes_count, |
| // mark unused trailing inodes |
| blocks_per_group - inodes_per_group |
| ); |
| // dump inode bitmap |
| //PUT((uint64_t)(FETCH_LE32(gd[i].bg_block_bitmap)) * blocksize, buf, blocksize); |
| //but it's right after block bitmap, so we can just: |
| xwrite(fd, buf, blocksize); |
| STORE_LE(gd[i].bg_free_inodes_count, gd[i].bg_free_inodes_count); |
| |
| // count overall free blocks |
| sb->s_free_blocks_count += free_blocks; |
| } |
| STORE_LE(sb->s_free_blocks_count, sb->s_free_blocks_count); |
| |
| // dump filesystem skeleton structures |
| // printf("Writing superblocks and filesystem accounting information: "); |
| for (i = 0, pos = first_block; i < ngroups; i++, pos += blocks_per_group) { |
| // dump superblock and group descriptors and their backups |
| if (has_super(i)) { |
| // N.B. 1024 byte blocks are special |
| PUT(((uint64_t)pos * blocksize) + ((0 == i && 1024 != blocksize) ? 1024 : 0), |
| sb, 1024); |
| PUT(((uint64_t)pos * blocksize) + blocksize, |
| gd, group_desc_blocks * blocksize); |
| } |
| } |
| |
| // zero boot sectors |
| memset(buf, 0, blocksize); |
| PUT(0, buf, 1024); // N.B. 1024 <= blocksize, so buf[0..1023] contains zeros |
| // zero inode tables |
| for (i = 0; i < ngroups; ++i) |
| for (n = 0; n < inode_table_blocks; ++n) |
| PUT((uint64_t)(FETCH_LE32(gd[i].bg_inode_table) + n) * blocksize, |
| buf, blocksize); |
| |
| // prepare directory inode |
| inode = (struct ext2_inode *)buf; |
| STORE_LE(inode->i_mode, S_IFDIR | S_IRWXU | S_IRGRP | S_IROTH | S_IXGRP | S_IXOTH); |
| STORE_LE(inode->i_mtime, timestamp); |
| STORE_LE(inode->i_atime, timestamp); |
| STORE_LE(inode->i_ctime, timestamp); |
| STORE_LE(inode->i_size, blocksize); |
| // inode->i_blocks stores the number of 512 byte data blocks |
| // (512, because it goes directly to struct stat without scaling) |
| STORE_LE(inode->i_blocks, blocksize / 512); |
| |
| // dump root dir inode |
| STORE_LE(inode->i_links_count, 3); // "/.", "/..", "/lost+found/.." point to this inode |
| STORE_LE(inode->i_block[0], FETCH_LE32(gd[0].bg_inode_table) + inode_table_blocks); |
| PUT(((uint64_t)FETCH_LE32(gd[0].bg_inode_table) * blocksize) + (EXT2_ROOT_INO-1) * inodesize, |
| buf, inodesize); |
| |
| // dump lost+found dir inode |
| STORE_LE(inode->i_links_count, 2); // both "/lost+found" and "/lost+found/." point to this inode |
| STORE_LE(inode->i_size, lost_and_found_blocks * blocksize); |
| STORE_LE(inode->i_blocks, (lost_and_found_blocks * blocksize) / 512); |
| n = FETCH_LE32(inode->i_block[0]) + 1; |
| for (i = 0; i < lost_and_found_blocks; ++i) |
| STORE_LE(inode->i_block[i], i + n); // use next block |
| //bb_info_msg("LAST BLOCK USED[%u]", i + n); |
| PUT(((uint64_t)FETCH_LE32(gd[0].bg_inode_table) * blocksize) + (EXT2_GOOD_OLD_FIRST_INO-1) * inodesize, |
| buf, inodesize); |
| |
| // dump directories |
| memset(buf, 0, blocksize); |
| dir = (struct ext2_dir *)buf; |
| |
| // dump 2nd+ blocks of "/lost+found" |
| STORE_LE(dir->rec_len1, blocksize); // e2fsck 1.41.4 compat (1.41.9 does not need this) |
| for (i = 1; i < lost_and_found_blocks; ++i) |
| PUT((uint64_t)(FETCH_LE32(gd[0].bg_inode_table) + inode_table_blocks + 1+i) * blocksize, |
| buf, blocksize); |
| |
| // dump 1st block of "/lost+found" |
| STORE_LE(dir->inode1, EXT2_GOOD_OLD_FIRST_INO); |
| STORE_LE(dir->rec_len1, 12); |
| STORE_LE(dir->name_len1, 1); |
| STORE_LE(dir->file_type1, EXT2_FT_DIR); |
| dir->name1[0] = '.'; |
| STORE_LE(dir->inode2, EXT2_ROOT_INO); |
| STORE_LE(dir->rec_len2, blocksize - 12); |
| STORE_LE(dir->name_len2, 2); |
| STORE_LE(dir->file_type2, EXT2_FT_DIR); |
| dir->name2[0] = '.'; dir->name2[1] = '.'; |
| PUT((uint64_t)(FETCH_LE32(gd[0].bg_inode_table) + inode_table_blocks + 1) * blocksize, buf, blocksize); |
| |
| // dump root dir block |
| STORE_LE(dir->inode1, EXT2_ROOT_INO); |
| STORE_LE(dir->rec_len2, 12); |
| STORE_LE(dir->inode3, EXT2_GOOD_OLD_FIRST_INO); |
| STORE_LE(dir->rec_len3, blocksize - 12 - 12); |
| STORE_LE(dir->name_len3, 10); |
| STORE_LE(dir->file_type3, EXT2_FT_DIR); |
| strcpy(dir->name3, "lost+found"); |
| PUT((uint64_t)(FETCH_LE32(gd[0].bg_inode_table) + inode_table_blocks + 0) * blocksize, buf, blocksize); |
| |
| // cleanup |
| if (ENABLE_FEATURE_CLEAN_UP) { |
| free(buf); |
| free(gd); |
| free(sb); |
| } |
| |
| xclose(fd); |
| return EXIT_SUCCESS; |
| } |