A storage module and host device for storage module defragmentation are disclosed. In one embodiment, a host controller sends a storage module a first set of logical block addresses of a file stored in the storage module. The host controller receives a metric from the storage module indicative of a fragmentation level of the file in physical blocks of memory in the storage module. If the metric is greater than a threshold, the host controller reads the file and then writes it back to the storage module using a different set of logical block addresses. To avoid sending the file back and forth, in another embodiment, the host controller sends the fragmentation threshold and the different set of logical block addresses to the storage module. The storage module then moves the file itself if the metric indicative of the fragmentation level is greater than the threshold. Other embodiments are provided.