SCSI Primary Commands - 2.pdf

T10/1236-D Revision 20 18 July 2001See figure 2 for a description of how a device server interprets a PREEMPT service action to determine the itsactions (e.g., preempt persistent reservation, remove registration or both preempt persistent reservation andremove reservation).PREEMPT service actionNoRequestinginitiatorregistered?YesRESERVATIONCONFLICTNoValidRESERVATIONKEY & SERVICE ACTIONRESERVATIONKEY?YesDoneYesExistingpersistentreservation?NoYesSERVICE ACTIONRESERVATION KEY matchespersistent reservation?Noa) Remove registration pointed to by the SERVICEACTION RESERVATION KEYb) Release reservationc) Create reservation using new TYPE and SCOPERemove registration pointed to bythe SERVICE ACTION RESERVATIONKEYDoneDoneFigure 2 — Device server interpretation of PREEMPT service action5.5.3.6.3.2 Failed persistent reservation preemptIf the preempting initiator’s PREEMPT service action or PREEMPT AND ABORT service action fails (e.g., TASKSET FULL, BUSY, transport protocol time-out or time-out due to queue blocked due to failed initiator), the initiatormay issue a LOGICAL UNIT RESET task management function to the failing logical unit to remove blocking tasksand then reissue the preempting service action.34 dpANS SCSI Primary Commands - 2 (SPC-2)