1. A method for faster data garbage collection (“GC”), the method comprising: determining to perform garbage collection on a data block of a non-volatile memory (“NVM”); loading a block table-of-contents (“TOC”) stored in the data block; comparing a bitmap stored in volatile memory with the block TOC; determining a subset of logical addresses of the data block that are mapped based on the comparison; performing garbage collection for only user data stored in the data block that are associated with the subset of logical addresses; for each logical address of the subset of logical addresses, consulting a tree stored in volatile memory to determine whether a logical-to-physical mapping exists for the logical address; in response to determining that the logical-to-physical mapping does not exist for the logical address, accessing an index page associated with the logical address; determining a physical address of the data block corresponding to the logical address based on the index page; and copying user data from the physical address to a different data block of the NVM.