Methods and structure for task management in storage controllers of a clustered storage system

Methods and structure for task management in storage controllers of a clustered storage system. An initiator storage controller of the clustered storage system ships I/O requests for processing to a target storage controller of the system. Responsive to a need to abort a previously shipped I/O request, the initiator storage controller transmits a task management message to the target storage controller. The task management message identifies one or more previously shipped I/O requests to be aborted. The target storage controller processes the received task management message in due course of processing requests and completes processing for the aborted previously shipped request in an orderly manner. Resources associated with the aborted previously shipped requests are release within both controllers.