1. A system for implementing block extent granularity authorization model processing in a Coherent Accelerator Processor Interface (CAPI) adapter comprising: the CAPI adapter comprising an authorization table, and a file system authorization function; said file system authorization function, authenticating data access for a CAPI client at an extent granularity and preventing an application from accessing unauthorized data in the CAPI adapter; and said authorization table providing for the CAPI client, a CAPI client identification (ID), a CAPI server register space assigning resource ownership to the CAPI client and a CAPI set of allowed functions.