Patent ID: 8583840
Filing Date: 2013-11-12
Classification: G06F,H04L

Abstract:
1. A method operable in a storage controller comprising a logical volume I/O request processing stack implemented as software executed by the storage controller and further comprising a fast path I/O request processing circuit, the method comprising: receiving in the storage controller a fast path I/O request from an attached host system, wherein the request is directed to a device identified by a device identifier in the received I/O request, and wherein the request includes a version identifier that specifies a version of logical to physical mapping information utilized by the host system in generating the fast path I/O request for the device; determining whether the version identifier in the fast path I/O request specifies a version of logical to physical mapping information that is presently utilized by the logical volume I/O request processing stack for generating I/O operations for the device; responsive to determining that the version identifier specifies the version of the logical to physical mapping information that is presently utilized by the I/O request processing stack, processing the fast path I/O request by operation of the fast path I/O request processing circuit of the storage controller; and responsive to determining that the version identifier specifies an older version of the logical to physical mapping information than that which is presently utilized by the request processing stack, transferring the fast path I/O request to the logical volume I/O request processing stack for subsequent processing.