static uint32_t ext4_balloc_bitmap_csum(struct ext4_sblock *sb,
void *bitmap)
{
uint32_t checksum = 0;
if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
uint32_t blocks_per_group = ext4_get32(sb, blocks_per_group);
/* First calculate crc32 checksum against fs uuid */
checksum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid,
sizeof(sb->uuid));
/* Then calculate crc32 checksum against block_group_desc */
checksum = ext4_crc32c(checksum, bitmap, blocks_per_group / 8);
}
return checksum;
}
static struct inode *open_ext4_db(char *file)
{
int fd;
struct ext4_extent_header *ihdr;
struct inode *inode;
struct db_handle *db;
struct block_device *bdev;
fd = device_open(file);
bdev = bdev_alloc(fd, 12);
inode = inode_alloc(bdev->bd_super);
/* For testing purpose, those data is hard-coded. */
inode->i_writeback = inode_sb_writeback;
memset(inode->i_uuid, 0xCC, sizeof(inode->i_uuid));
inode->i_inum = 45;
inode->i_csum = ext4_crc32c(~0, inode->i_uuid, sizeof(inode->i_uuid));
inode->i_csum =
ext4_crc32c(inode->i_csum, &inode->i_inum, sizeof(inode->i_inum));
inode->i_csum = ext4_crc32c(inode->i_csum, &inode->i_generation,
sizeof(inode->i_generation));
if (!device_size(bdev))
exit(EXIT_FAILURE);
db = db_open(inode->i_sb);
ihdr = ext4_ext_inode_hdr(inode);
memcpy(ihdr, db->db_header->db_tree_base, sizeof(inode->i_data));
if (ihdr->eh_magic != EXT4_EXT_MAGIC) {
ext4_ext_init_i_blocks(ihdr);
inode->i_data_dirty = 1;
}
inode->i_db = db;
return inode;
}
static uint32_t
ext4_dir_dx_checksum(struct ext4_inode_ref *inode_ref,
void *dirent,
int count_offset, int count, struct ext4_directory_dx_tail *t)
{
uint32_t orig_checksum, checksum = 0;
struct ext4_sblock *sb = &inode_ref->fs->sb;
int size;
/* Compute the checksum only if the filesystem supports it */
if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
uint32_t ino_index = to_le32(inode_ref->index);
uint32_t ino_gen =
to_le32(ext4_inode_get_generation(inode_ref->inode));
size = count_offset +
(count * sizeof(struct ext4_directory_dx_tail));
orig_checksum = t->checksum;
t->checksum = 0;
/* First calculate crc32 checksum against fs uuid */
checksum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid,
sizeof(sb->uuid));
/* Then calculate crc32 checksum against inode number
* and inode generation */
checksum = ext4_crc32c(checksum, &ino_index,
sizeof(ino_index));
checksum = ext4_crc32c(checksum, &ino_gen,
sizeof(ino_gen));
/* After that calculate crc32 checksum against all the dx_entry */
checksum = ext4_crc32c(checksum, dirent, size);
/* Finally calculate crc32 checksum for dx_tail */
checksum = ext4_crc32c(checksum, t,
sizeof(struct ext4_directory_dx_tail));
t->checksum = orig_checksum;
}
return checksum;
}
