diff options
| -rw-r--r-- | include/usage.h | 2 | ||||
| -rw-r--r-- | util-linux/mkfs_ext2.c | 66 |
2 files changed, 44 insertions, 24 deletions
diff --git a/include/usage.h b/include/usage.h index bdd9ae3..80111e5 100644 --- a/include/usage.h +++ b/include/usage.h @@ -2724,7 +2724,7 @@ "[-L LABEL] " \ "[-n] " \ /* "[-M last-mounted-directory] [-S] [-T filesystem-type] " */ \ - "DEVICE [BLK_COUNT]" + "DEVICE [KBYTES]" #define mkfs_ext2_full_usage "\n" \ "\n -b BLK_SIZE Block size in bytes" \ /* "\n -c Check for bad blocks before creating" */ \ diff --git a/util-linux/mkfs_ext2.c b/util-linux/mkfs_ext2.c index a990668..56203c7 100644 --- a/util-linux/mkfs_ext2.c +++ b/util-linux/mkfs_ext2.c @@ -70,7 +70,11 @@ static unsigned int_log2(unsigned arg) // taken from mkfs_minix.c. libbb candidate? static unsigned div_roundup(uint32_t size, uint32_t n) { - return (size + n-1) / 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) @@ -161,6 +165,7 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv) unsigned i, pos, n; unsigned bs, blocksize, blocksize_log2; unsigned nreserved = 5; + unsigned long long nblocks_ull; uint32_t nblocks; uint32_t ngroups; unsigned bytes_per_inode; @@ -179,23 +184,13 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv) struct ext2_dir *dir; uint8_t *buf; - bs = EXT2_MIN_BLOCK_SIZE; opt_complementary = "-1:b+:m+:i+"; opts = getopt32(argv, "cl:b:f:i:I:J:G:N:m:o:g:L:M:O:r:E:T:U:jnqvFS", NULL, &bs, NULL, &bytes_per_inode, NULL, NULL, NULL, NULL, &nreserved, NULL, NULL, &label, NULL, NULL, NULL, NULL, NULL, NULL); argv += optind; // argv[0] -- device - // block size minimax, block size is a multiple of minimum - 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("-%c is bad", 'b'); - } - - // reserved blocks count + // reserved blocks percentage if (nreserved > 50) bb_error_msg_and_die("-%c is bad", 'm'); @@ -210,6 +205,42 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv) if (find_mount_point(argv[0], 0)) bb_error_msg_and_die("can't format mounted filesystem"); + // open the device, get size in kbytes + xmove_fd(xopen3(argv[0], O_WRONLY | O_CREAT, 0666), fd); + if (argv[1]) { + nblocks_ull = xatoull(argv[1]); + } else { + nblocks_ull = (uoff_t)xlseek(fd, 0, SEEK_END) / 1024; + } + + // block size is a multiple of 1024 + blocksize = 1024; + if (nblocks_ull >= 512*1024) // mke2fs 1.41.9 compat + blocksize = 4096; + if (EXT2_MAX_BLOCK_SIZE > 4096) { + // nblocks_ull >> 22 == size in 4gigabyte chunks. + // if it is >= 16k gigs, blocksize must be increased. + // Try "mke2fs -F image_std $((16 * 1024*1024*1024))" + while ((nblocks_ull >> 22) >= blocksize) + blocksize *= 2; + } + if (opts & 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); + } + blocksize_log2 = int_log2(blocksize); + nblocks_ull >>= (blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE); + // nblocks: the total number of blocks in the filesystem + nblocks = nblocks_ull; + if (nblocks != nblocks_ull) + bb_error_msg_and_die("block count doesn't fit in 32 bits"); + if (nblocks < 8) + bb_error_msg_and_die("need >= 8 blocks"); + // TODO: 5?/5 WE MUST NOT DEPEND ON WHETHER DEVICE IS /dev/zero 'ed OR NOT // TODO: 3/5 refuse if mounted // TODO: 4/5 compat options @@ -226,7 +257,6 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv) sb->s_magic = EXT2_SUPER_MAGIC; sb->s_inode_size = sizeof(*inode); sb->s_first_ino = EXT2_GOOD_OLD_FIRST_INO; - blocksize_log2 = int_log2(blocksize); sb->s_log_block_size = 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 available for data is 1, otherwise 0 @@ -261,18 +291,8 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv) */ sb->s_max_mnt_count += sb->s_uuid[ARRAY_SIZE(sb->s_uuid)-1] % EXT2_DFL_MAX_MNT_COUNT; - // open the device, get number of blocks - xmove_fd(xopen3(argv[0], O_WRONLY | O_CREAT, 0666), fd); - if (argv[1]) { - nblocks = xatou(argv[1]); - } else { - nblocks = (uoff_t)xlseek(fd, 0, SEEK_END) >> blocksize_log2; - } sb->s_blocks_count = nblocks; - // nblocks is the total number of blocks in the filesystem - if (nblocks < 8) - bb_error_msg_and_die("nblocks"); // reserve blocks for superuser sb->s_r_blocks_count = ((uint64_t) nblocks * nreserved) / 100; |