_ReadBlock
error = _ReadBlock(number, &block);
status_t _ReadBlock(uint64 number, Block **block);
status_t error = _ReadBlock(0, partitionTable);
status_t error = _ReadBlock(logical->PartitionTableOffset(),
status_t error = _ReadBlock(primary->Offset(), partitionTable);
status_t _ReadBlock(off_t offset,
error = _ReadBlock(block, blockIndex);