Method and apparatus for coordination of client/server processes

Abstract

The invention provides for the coordination of client/server processes. One or more embodiments provide a completion object comprised of various states of completion of a client request. The completion object may be manipulated to transition from one state to another by both the client and server. The following states of completion may be provided: idle, ready, active, completing, completed, and acknowledged. In the idle state, the completion object is obtained by the client (by constructing a new object or retrieving an existing object that has been recycled). In the ready state, the request has been initialized but not yet issued to the server or I/O device. In the active state, the server processes the I/O request. In the completing state, the server has completed the I/O operations requested but has not yet stored the results. In the completed state, the server stores the results to be returned to the client and notifies the client. At the acknowledged state, the client examines the results, performs additional operations and frees up the completion object for use by another client request. Depending on the state of the completion object, a request to cancel the I/O operations may require varying actions. The completion object provides the ability to easily and quickly determine where in the completion process an I/O request is. Further, when a client request is canceled, the completion object provides the ability to easily identify the actions necessary to properly cancel the request.

1 . A system comprising: one or more processors; a memory coupled to said one or more processors; one or more sequences of instructions which, when executed by said one or more processors, cause said one or more processors to perform the steps of: obtaining a completion object associated with a first request from at least one client to at least one server, wherein said completion object indicates a state of completion of said first request; transitioning said completion object from indicating a first state of completion of said first request to indicating a second state of completion of said first request in response to a message from said at least one client; and transitioning said completion object from indicating a third state of completion of said first request to indicating a fourth state of completion of said first request in response to a message from said at least one server; wherein said second state of completion and said third state of completion are the same state of completion.