METHOD AND SYSTEM FOR PROCESSING ACCESS TO DISK BLOCK

• US 20080235474A1
• Filed: 03/21/2008
• Published: 09/25/2008
• Est. Priority Date: 03/21/2007
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: SUH, Sang-bum, HWANG, Joo-young, RYU, Jae-min
• Granted Patent: US 8,335,903 B2
• Time in Patent Office: Days
• US Class Current: 711/163
• CPC Class Codes: G06F 12/0815 Cache consistency protocols
• CPC Class Codes: G06F 12/0842 for multiprocessing or multitasking
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: G06F 2212/284 being distributed
• CPC Class Codes: G06F 2212/311 In host system
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0637 Permissions
• CPC Class Codes: G06F 3/064 Management of blocks
• CPC Class Codes: G06F 3/0676 Magnetic disk device
• CPC Class Codes: G06F 9/526 Mutual exclusion algorithms

Abstract

Provided are a method and a system for processing an access to a disk block. The system receives a disk block access request from an OS domain, determines whether the OS domain is permitted to access a disk block with reference to a predetermined block table and processes disk block access of the OS domain according to the determination result. Accordingly, OS domains can share caches without having data copy through memory access control in a virtual machine monitor environment. Furthermore, a device domain controls access to a disk drive so that data corruption can be prevented.

Claims

1. A method for processing an Operating System (OS) domain access to a disk block in an environment in which at least one OS domain is executed on a virtual machine monitor, the method comprising:

receiving a disk block access request from a first OS domain;

determining whether the first OS domain is permitted to access the disk block with reference to a block table to generate a determination result; and

processing an access of the disk block by the first OS domain according to the determination result.

2. The method of claim 1, further comprising sharing a disk block stored in a buffer cache of a second OS domain with the first OS domain according to the determination result.

3. The method of claim 1, wherein the block table includes a home node representing an OS domain of a node having a cached page for the disk block, and the processing of the access of the disk block comprises requesting an OS domain corresponding to the home node to test a buffer cache of the OS domain corresponding to the home node.

4. The method of claim 3, wherein, if the disk block is cached in the OS domain corresponding to the home node, the processing of the access of the disk block comprises:

requesting the virtual machine monitor to update a page table of the first OS domain such that the first OS domain and the OS domain corresponding to the home node share the page of the disk block; and

returning the address of the shared page to the first OS domain.

5. The method of claim 1, wherein, when the disk block is not cached in a second OS domain, the processing of the access of the disk block comprises accessing a disk drive to make the disk drive copy data of the disk block to a page of the first OS domain.

6. The method of claim 5, wherein the disk drive is accessed using a native driver.

7. The method of claim 1, wherein the block table includes a lock type representing a shared state of the disk block.

8. The method of claim 7, wherein the lock type includes idle, multiple reader and exclusive writer.

9. The method of claim 1, wherein the block table includes a lock holder representing OS domains having permission to access the disk block.

10. The method of claim 1, wherein the block table includes a lock type, a lock holder, a home node and a page address of the disk block.

11. The method of claim 1, wherein the disk block access request is a request for permission to read/write data from/to the disk block.

12. A method of processing a disk block access, the method comprising:

requesting from a device domain, by a first OS domain, access to a disk block;

requesting, by the device domain, a second OS domain to check whether a buffer cache thereof caches the disk block with reference to a predetermined block table;

requesting, by the device domain, a virtual machine monitor to update a page table of the first OS domain such that the first OS domain and the second OS domain caching the disk block in the buffer cache thereof share the page of the disk block according to the checking result; and

returning, by the device domain, the address of the shared page of the disk block to the first OS domain.

13. A computer readable recording medium storing instructions for causing a computer executing the instructions to perform the method of claim

14. A system for processing an Operating System (OS) domain access to a disk block in an environment in which at least one OS domain is executed on a virtual machine monitor, the system comprising:

a device domain receiving a disk block access request from a first OS domain,

determining whether the first OS domain is permitted to access the disk block with reference to a block table to generate a determination result, and

processing an access of the disk block by the first OS domain according to the determination result.

15. The system of claim 14, wherein the device domain comprises a block table that includes at least one of a lock type, a lock holder, a home node and a page address of the disk block.

16. The system of claim 14, wherein, if the disk block is cached in a second OS domain, the device domain requests the virtual machine monitor to update a page table of the first OS domain such that the first OS domain shares the page of the disk block and returns the address of the shared page to the first OS domain according to update of the page table.

17. The system of claim 14, wherein, when the disk block is not cached in a second OS domain, the device domain accesses a disk drive to make the disk drive copy data of the disk block to a page of the first OS domain.

18. The system of claim 14, wherein the device domain comprises:

a back-end driver communicating with a front-end driver of the first OS domain through an event channel of the virtual machine monitor; and

a native driver accessing the disk drive.

19. The system of claim 14, wherein the device domain comprises a victim page cache that copies data of a page that is to be replaced from an arbitrary OS domain.

20. The system of claim 14, wherein the disk block access request is a request for permission to read/write data from/to the disk block.