LFS_MINBLOCKSIZE
bsize = strsuftoi64("block size", optarg, LFS_MINBLOCKSIZE, INT64_MAX, NULL);
fsize = strsuftoi64("fragment size", optarg, LFS_MINBLOCKSIZE, INT64_MAX, NULL);
ibsize = strsuftoi64("inode block size", optarg, LFS_MINBLOCKSIZE, INT64_MAX, NULL);