Method of storage space management for improving endurance of storage devices

A method of storage space management for a storage device, the storage device comprising a controller and a memory, the storage device having a declared capacity, the method of storage space management comprising:

• calculating, by the controller, an expectedly used capacity and an effective capacity of the memory, wherein the effective capacity decreases a number of blocks marked as bad blocks in a plurality of blocks of the memory increases, wherein the expectedly used capacity is a sum of a currently used capacity of the memory and a size of a data entry to be currently written into the memory;
• determining, by the controller, whether the plurality of blocks of the memory include one or more blocks that are non-bad blocks and are prohibited from reading/writing;
• when the one or more blocks are determined to be non-bad blocks and to be prohibited from reading/writing, marking, by the controller, each of the one or more blocks as a restricted block other than a bad block, thereby maintaining the effective capacity to be unchanged;
• and
• comparing, by the controller, a difference of the effective capacity and a total capacity of the one or more blocks that are marked as the restricted block to the expectedly used capacity to determine whether to prohibit programming to the memory.