Storage device and method for sudden power off recovery thereof

A storage device comprising a volatile memory, a non-volatile memory, and a controller, the controller coupled to the volatile memory and the non-volatile memory, the controller comprises:

• a processor, configured to execute a program code for a method for sudden power off recovery of the storage device to:
• perform a first snapshot operation on the storage device to obtain system information of the storage device, and write the system information and a first tag to the non-volatile memory when the storage device is in an idle state;
• perform a second snapshot operation on the storage device to obtain system information of the storage device, and write the system information and a second tag to the non-volatile memory, when it is determined that at least one of the following situations occurs:
• a logical-to-physical mapping table is updated in the non-volatile memory, a garbage collection operation is executed, and a new block is programmed;
• search the latest system information written in the non-volatile memory, and determine whether the searched system information comprises the first tag when supply of power is recovered after a power failure;
• perform a lightweight SPOR operation in the storage device when the searched system information comprises the first tag;
• and
• perform a formal sudden power off recovery (SPOR) operation in the storage device when the searched system information comprises the second tag;
• wherein a complexity of the lightweight SPOR operation is simpler than that of the formal SPOR operation;
• wherein the first tag and the second tag are different.