/* 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. */ //usage:#define mkfs_ext2_trivial_usage //usage: "[-Fn] " /* //usage: "[-c|-l filename] " */ //usage: "[-b BLK_SIZE] " /* //usage: "[-f fragment-size] [-g blocks-per-group] " */ //usage: "[-i INODE_RATIO] [-I INODE_SIZE] " /* //usage: "[-j] [-J journal-options] [-N number-of-inodes] " */ //usage: "[-m RESERVED_PERCENT] " /* //usage: "[-o creator-os] [-O feature[,...]] [-q] " */ /* //usage: "[r fs-revision-level] [-E extended-options] [-v] [-F] " */ //usage: "[-L LABEL] " /* //usage: "[-M last-mounted-directory] [-S] [-T filesystem-type] " */ //usage: "BLOCKDEV [KBYTES]" //usage:#define mkfs_ext2_full_usage "\n\n" //usage: " -b BLK_SIZE Block size, bytes" /* //usage: "\n -c Check device for bad blocks" */ /* //usage: "\n -E opts Set extended options" */ /* //usage: "\n -f size Fragment size in bytes" */ //usage: "\n -F Force" /* //usage: "\n -g N Number of blocks in a block group" */ //usage: "\n -i RATIO Max number of files is filesystem_size / RATIO" //usage: "\n -I BYTES Inode size (min 128)" /* //usage: "\n -j Create a journal (ext3)" */ /* //usage: "\n -J opts Set journal options (size/device)" */ /* //usage: "\n -l file Read bad blocks list from file" */ //usage: "\n -L LBL Volume label" //usage: "\n -m PERCENT Percent of blocks to reserve for admin" /* //usage: "\n -M dir Set last mounted directory" */ //usage: "\n -n Dry run" /* //usage: "\n -N N Number of inodes to create" */ /* //usage: "\n -o os Set the 'creator os' field" */ /* //usage: "\n -O features Dir_index/filetype/has_journal/journal_dev/sparse_super" */ /* //usage: "\n -q Quiet" */ /* //usage: "\n -r rev Set filesystem revision" */ /* //usage: "\n -S Write superblock and group descriptors only" */ /* //usage: "\n -T fs-type Set usage type (news/largefile/largefile4)" */ /* //usage: "\n -v Verbose" */ #include "libbb.h" #include <linux/fs.h> #include "bb_e2fs_defs.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); // Disabled: standard mke2fs doesn't do this, and // on SPARC this destroys Sun disklabel. // Users who need/want zeroing can easily do it with dd. //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; }