Data storage device and flash memory control method

A data storage device, comprising:

• a flash memory, divided into a plurality of blocks with each block comprising a plurality of physical pages;
• and
• a control unit, coupling the flash memory to a host and comprising a microcontroller and a random access memory,
• wherein:
• the microcontroller maintains a plurality of logical-to-physical address mapping tables and a link table on the flash memory to record mapping information between the host and the flash memory and records a link table indicator on the flash memory to indicate a position of the link table;
• the link table indicates positions of the plurality of logical-to-physical address mapping tables, and each entry in the link table corresponds to one logical-to-physical address mapping table;
• and
• the microcontroller erases user of logical addresses corresponding to N logical-to-physical address mapping tables by downloading the link table from the flash memory to the random access memory, invalidating N entries corresponding to the N logical-to-physical address mapping tables in the link table on the random access memory, uploading the link table with the N entries of invalid data back to the flash memory, and records an updated link table indicator on the flash memory to indicate a position of the uploaded link table on the flash memory, where N is an integer.