Method for handling persistent reservation registrations in a storage device

• US 6,704,810 B1
• Filed: 08/27/2002
• Issued: 03/09/2004
• Est. Priority Date: 08/27/2002
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: LSI Logic Corporation (Broadcom, Inc.)
• Inventors: Ulrich, David J., Krehbiel, Stanley E. Jr.
• Primary Examiner(s): Shin, Christopher B.
• Application Number:
  US10/231,331
• Publication Number:
  US 20040044800A1
• Time in Patent Office: 560 Days
• Field of Search: 710/5-7, 710/15-19, 710/20-21, 710/58-61, 712/216-219, 711/141, 711/164, 713/2, 713/300
• US Class Current: 710/5
• CPC Class Codes: G11C 7/20 Memory cell initialisation circuits, e.g. when powering up or down, memory clear, latent image memory
• CPC Class Codes: G11C 7/24 Memory cell safety or protection circuits, e.g. arrangements for preventing inadvertent reading or writing; Status cells; Test cells

Abstract

Persistent reservations may be processed on an as-needed basis after a power cycle sequence. A computer storage device may have persistent reservations for various volumes that are to be deleted after a power cycle but before accepting any reservation I/O requests for those volumes. After a start up sequence, the device comes on-line prior to deleting the required registrations. Prior to the first reservation I/O request for the particular volume, the registrations are processed for that volume and the necessary registrations are deleted.

Claims

1. A method for processing persistent reservations after a power cycle in a computer storage device with multiple volumes comprising:

completing a power-on sequence after a power cycle;

setting the status of said storage device to receive I/O requests;

receiving a reservation I/O request for a volume of said storage device, said volume having at least one persistent reservation that is to persist through a restart but not a power cycle;

determining that a power cycle has occurred and that said reservation is not to persist after said power cycle;

performing at least some processing on said reservation; and

processing said reservation I/O request.

2. The method of claim 1 wherein said power-on sequence comprises setting a power-on bit for each of said multiple volumes, said power-on bit being used to indicate if at least one registration for said volume must be deleted prior to accepting said I/O request.

3. The method of claim 1 wherein said computer storage device is a SCSI device.

4. The method of claim 1 wherein said processing on said reservation comprises deleting at least one registration.

5. A computer storage device of multiple volumes with reservations that persist after a reset but not a power cycle comprising:

a storage medium comprising multiple volumes; and

a controller for said storage device adapted to completing a power-on sequence after a power cycle, setting the status of said storage device to receive I/O requests, receiving a reservation I/O request for a volume of said storage device, said volume having at least one persistent reservation that is to persist through a restart but not a power cycle, determining that a power cycle has occurred and that said reservation is not to persist after said power cycle, performing at least some processing on said reservation, and processing said reservation I/O request.

6. The computer storage device of claim 5 further comprising:

a power-on bit for each of said multiple volumes wherein said power-on bit indicates if at least one registration must be deleted prior to processing a reservation I/O request for said volume.

7. The computer storage device of claim 5 wherein said computer storage device is a SCSI device.

8. The computer storage device of claim 5 wherein said processing on said reservation comprises deleting at least one registration.