A controller addresses portions of non-volatile memory via a memory interface using physical addresses and addresses portions of host data via the host interface using logical addresses. The controller maintains logical to physical mappings and physical to logical mappings for the logical addresses and the physical addresses. The controller is configured to move data from a source logical address to a destination logical address by updating logical to physical mappings and physical address to logical mappings without instructing the non-volatile memory to move the data between physical locations. In one embodiment, this process is used to implement a command to move or defragment data.