void ext4_create_resize_inode() { struct block_allocation *reserve_inode_alloc = create_allocation(); u32 reserve_inode_len = 0; unsigned int i; struct ext4_inode *inode = get_inode(EXT4_RESIZE_INO); if (inode == NULL) { error("failed to get resize inode"); return; } for (i = 0; i < aux_info.groups; i++) { if (ext4_bg_has_super_block(i)) { u64 group_start_block = aux_info.first_data_block + i * info.blocks_per_group; u32 reserved_block_start = group_start_block + 1 + aux_info.bg_desc_blocks; u32 reserved_block_len = info.bg_desc_reserve_blocks; append_region(reserve_inode_alloc, reserved_block_start, reserved_block_len, i); reserve_inode_len += reserved_block_len; } } inode_attach_resize(inode, reserve_inode_alloc); inode->i_mode = S_IFREG | S_IRUSR | S_IWUSR; inode->i_links_count = 1; free_alloc(reserve_inode_alloc); }
/* Compute the rest of the parameters of the filesystem from the basic info */ void ext4_create_fs_aux_info() { aux_info.first_data_block = (info.block_size > 1024) ? 0 : 1; aux_info.len_blocks = info.len / info.block_size; aux_info.inode_table_blocks = DIV_ROUND_UP(info.inodes_per_group * info.inode_size, info.block_size); aux_info.groups = DIV_ROUND_UP(aux_info.len_blocks - aux_info.first_data_block, info.blocks_per_group); aux_info.blocks_per_ind = info.block_size / sizeof(u32); aux_info.blocks_per_dind = aux_info.blocks_per_ind * aux_info.blocks_per_ind; aux_info.blocks_per_tind = aux_info.blocks_per_dind * aux_info.blocks_per_dind; aux_info.bg_desc_blocks = DIV_ROUND_UP(aux_info.groups * sizeof(struct ext2_group_desc), info.block_size); aux_info.default_i_flags = EXT4_NOATIME_FL; u32 last_group_size = aux_info.len_blocks % info.blocks_per_group; u32 last_header_size = 2 + aux_info.inode_table_blocks; if (ext4_bg_has_super_block(aux_info.groups - 1)) last_header_size += 1 + aux_info.bg_desc_blocks + info.bg_desc_reserve_blocks; if (last_group_size > 0 && last_group_size < last_header_size) { aux_info.groups--; aux_info.len_blocks -= last_group_size; } aux_info.sb = calloc(info.block_size, 1); /* Alloc an array to hold the pointers to the backup superblocks */ aux_info.backup_sb = calloc(aux_info.groups, sizeof(char *)); if (!aux_info.sb) critical_error_errno("calloc"); aux_info.bg_desc = calloc(info.block_size, aux_info.bg_desc_blocks); if (!aux_info.bg_desc) critical_error_errno("calloc"); aux_info.xattrs = NULL; }
/* Fill in the superblock memory buffer based on the filesystem parameters */ void ext4_fill_in_sb() { unsigned int i; struct ext4_super_block *sb = aux_info.sb; sb->s_inodes_count = info.inodes_per_group * aux_info.groups; sb->s_blocks_count_lo = aux_info.len_blocks; sb->s_r_blocks_count_lo = 0; sb->s_free_blocks_count_lo = 0; sb->s_free_inodes_count = 0; sb->s_first_data_block = aux_info.first_data_block; sb->s_log_block_size = log_2(info.block_size / 1024); sb->s_obso_log_frag_size = log_2(info.block_size / 1024); sb->s_blocks_per_group = info.blocks_per_group; sb->s_obso_frags_per_group = info.blocks_per_group; sb->s_inodes_per_group = info.inodes_per_group; sb->s_mtime = 0; sb->s_wtime = 0; sb->s_mnt_count = 0; sb->s_max_mnt_count = 0xFFFF; sb->s_magic = EXT4_SUPER_MAGIC; sb->s_state = EXT4_VALID_FS; sb->s_errors = EXT4_ERRORS_RO; sb->s_minor_rev_level = 0; sb->s_lastcheck = 0; sb->s_checkinterval = 0; sb->s_creator_os = EXT4_OS_LINUX; sb->s_rev_level = EXT4_DYNAMIC_REV; sb->s_def_resuid = EXT4_DEF_RESUID; sb->s_def_resgid = EXT4_DEF_RESGID; sb->s_first_ino = EXT4_GOOD_OLD_FIRST_INO; sb->s_inode_size = info.inode_size; sb->s_block_group_nr = 0; sb->s_feature_compat = info.feat_compat; sb->s_feature_incompat = info.feat_incompat; sb->s_feature_ro_compat = info.feat_ro_compat; generate_uuid("extandroid/make_ext4fs", info.label, sb->s_uuid); memset(sb->s_volume_name, 0, sizeof(sb->s_volume_name)); strncpy(sb->s_volume_name, info.label, sizeof(sb->s_volume_name)); memset(sb->s_last_mounted, 0, sizeof(sb->s_last_mounted)); sb->s_algorithm_usage_bitmap = 0; sb->s_reserved_gdt_blocks = info.bg_desc_reserve_blocks; sb->s_prealloc_blocks = 0; sb->s_prealloc_dir_blocks = 0; //memcpy(sb->s_journal_uuid, sb->s_uuid, sizeof(sb->s_journal_uuid)); if (info.feat_compat & EXT4_FEATURE_COMPAT_HAS_JOURNAL) sb->s_journal_inum = EXT4_JOURNAL_INO; sb->s_journal_dev = 0; sb->s_last_orphan = 0; sb->s_hash_seed[0] = 0; /* FIXME */ sb->s_def_hash_version = DX_HASH_TEA; sb->s_reserved_char_pad = EXT4_JNL_BACKUP_BLOCKS; sb->s_desc_size = sizeof(struct ext2_group_desc); sb->s_default_mount_opts = 0; /* FIXME */ sb->s_first_meta_bg = 0; sb->s_mkfs_time = 0; //sb->s_jnl_blocks[17]; /* FIXME */ sb->s_blocks_count_hi = aux_info.len_blocks >> 32; sb->s_r_blocks_count_hi = 0; sb->s_free_blocks_count_hi = 0; sb->s_min_extra_isize = sizeof(struct ext4_inode) - EXT4_GOOD_OLD_INODE_SIZE; sb->s_want_extra_isize = sizeof(struct ext4_inode) - EXT4_GOOD_OLD_INODE_SIZE; sb->s_flags = 0; sb->s_raid_stride = 0; sb->s_mmp_interval = 0; sb->s_mmp_block = 0; sb->s_raid_stripe_width = 0; sb->s_log_groups_per_flex = 0; sb->s_kbytes_written = 0; for (i = 0; i < aux_info.groups; i++) { u64 group_start_block = aux_info.first_data_block + i * info.blocks_per_group; u32 header_size = 0; if (ext4_bg_has_super_block(i)) { if (i != 0) { aux_info.backup_sb[i] = calloc(info.block_size, 1); memcpy(aux_info.backup_sb[i], sb, info.block_size); /* Update the block group nr of this backup superblock */ aux_info.backup_sb[i]->s_block_group_nr = i; queue_data_block((u8 *)aux_info.backup_sb[i], info.block_size, group_start_block); } queue_data_block((u8 *)aux_info.bg_desc, aux_info.bg_desc_blocks * info.block_size, group_start_block + 1); header_size = 1 + aux_info.bg_desc_blocks + info.bg_desc_reserve_blocks; } aux_info.bg_desc[i].bg_block_bitmap = group_start_block + header_size; aux_info.bg_desc[i].bg_inode_bitmap = group_start_block + header_size + 1; aux_info.bg_desc[i].bg_inode_table = group_start_block + header_size + 2; aux_info.bg_desc[i].bg_free_blocks_count = sb->s_blocks_per_group; aux_info.bg_desc[i].bg_free_inodes_count = sb->s_inodes_per_group; aux_info.bg_desc[i].bg_used_dirs_count = 0; } }