A method and system are disclosed that permit a host application to obtain cluster location data, for example logical addresses associated with the clusters of a file, and a host application to communicate the logical block address mapping information to firmware of a storage device. The method includes the host transmitting one or more clusters or partial clusters having a signature to the storage device where the storage device knows or has been instructed to look for the signature. The storage device may receive clusters having a signature and, responsive to a host request, return logical address information to a host for the location in the storage device of the marked clusters. The host may parse a data structure on the storage device to obtain remaining cluster location information using a file's first cluster location or may request that the storage device return the cluster location information.