Distributed Lock Manager For File System Objects In A Shared File System

• US 20080319996A1
• Filed: 06/20/2007
• Published: 12/25/2008
• Est. Priority Date: 06/20/2007
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Cook, Steven D.
• Granted Patent: US 8,990,954 B2
• Time in Patent Office: Days
• US Class Current: 707/8
• CPC Class Codes: G06F 11/1435 using file system or storage system metadata
• CPC Class Codes: G06F 16/1774 Locking methods, e.g. locking methods for file systems allowing shared and concurrent access to files
• CPC Class Codes: G06F 16/1858 Parallel file systems, i.e. file systems supporting multiple processors
• CPC Class Codes: G06F 21/604 Tools and structures for managing or administering access control systems
• CPC Class Codes: G06F 21/6218 to a system of files or objects, e.g. local or distributed file system or database
• CPC Class Codes: G06F 9/465 Distributed object oriented systems remote method invocation [RMI] G06F9/548
• CPC Class Codes: G06F 9/52 Program synchronisation; Mutual exclusion, e.g. by means of semaphores
• CPC Class Codes: H04L 63/10 for controlling access to devices or network resources
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]

Abstract

A method and apparatus are provided for mediating access to a shared object in a naive computer system having a shared-nothing operating system layered on a shared file system. At least one primary token is utilized as a tool to mediate ownership of one or more shared objects in the naive system. A secondary token is created and utilized to mediate ownership of one or more shared objects. The secondary token created and utilized in limited circumstances, such as when the owner of the primary token ceases communicating with one or more requesters of the primary token.

Claims

1. A method for managing a shared file system comprising:

establishing a primary token in a computer system as an element to control access to an object in a shared file system, wherein said computer system includes a processor operating in a shared-nothing environment co-existing with a shared file system;

requesting ownership of said primary token by said processor from a prior owner of said primary token;

receiving a response from said prior owner of said primary token, wherein said response is selected from the group consisting of;

silent, unexpected, and expected negative; and

creating a secondary token in response to receipt of said response, wherein said secondary token is used to take ownership of said object in said file system protected by said primary token.

2. The method of claim 1, further comprising broadcasting primary token invalidation information to each server with access to said file system.

3. The method of claim 2, further comprising returning to use of said primary token when it becomes available.

4. The method of claim 3, further comprising releasing and invalidating said secondary token to all servers with access to said file system in conjunction with return of said primary token.

5. The method of claim 1, wherein the step of requesting said primary token from said prior owner includes issuing a heartbeat to said owner of said primary token to determine if said prior owner is in communication with a server requesting said primary token.

6. The method of claim 1, wherein said token is selected from the group consisting of:

a file, a directory, meta data, an attribute of the file system, and an object in the file system.

7. A computer system, comprising:

a shared file system;

a processor operating a shared-nothing operating system in communication with said shared file system;

a manager to request ownership of a primary token from a prior owner of said primary token, said primary token provides the control access to an object in said file system as shared resource;

said manager receives a negative response from said prior owner of said primary token, wherein said response is selected from the group consisting of;

silent, unexpected, and expected negative;

said manager issues a secondary token in response to receipt of said negative response from said prior owner, wherein said secondary token is used to take ownership of said object in said file system protected by said primary token.

8. The system of claim 7, further comprising said manager to broadcast primary token invalidation information to each server with access to said file system.

9. The system of claim 8, further comprising a return to use of said primary token when it becomes available.

10. The system of claim 9, further comprising said manager to release and invalidate said secondary token to all servers with access to said file system in conjunction with return of said primary token.

11. The system of claim 7, wherein the request of said primary token from said prior owner includes issuance of a heartbeat to said owner of said primary token to determine if said prior owner is in communication with a server requesting said primary token.

12. The system of claim 7, wherein said token is selected from the group consisting of:

a file, a directory, meta data, an attribute of the file system, and an object in the file system.

13. An article comprising:

a computer readable carrier including computer program instructions configured to manage a shared file system comprising;

instructions to establish a primary token in a computer system as an element to control access to an object in said shared file system, wherein said computer system is a shared-nothing environment layered with said shared file system;

instructions to issue a request for said primary token from a requesting server to a server owning said primary token; and

instructions to issue a secondary token in response to receipt of a response from said owning server, wherein said response is selected from the group consisting of;

silent, unexpected, and expected negative, and wherein said secondary token is used to take ownership of said object in said file system protected by said primary token.

14. The article of claim 13, further comprising instructions to broadcast primary token invalidation information to each server with access to said file system.

15. The article of claim 14, further comprising instructions to return to use of said primary token when it becomes available.

16. The article of claim 15, further comprising instructions to release and invalidate said secondary token to all servers with access to said file system in conjunction with return of said primary token.

17. The article of claim 13, wherein the instructions to request said primary token from said prior owner includes instructions to issue a heartbeat to said owner of said primary token to determine if said prior owner is in communication with a server requesting said primary token.

18. The article of claim 13, wherein said token is selected from the group consisting of:

a file, a directory, meta data, an attribute of the file system, and an object in the file system.

19. A method for managing a shared file system comprising:

establishing a primary token in a computer system as an element to control access to an object in a shared file system, wherein said computer system includes a processor operating in a shared-nothing environment co-existing with a shared file system;

requesting ownership of said primary token from a prior owner of said primary token; and

creating a secondary token in said system in response to receipt of a negative response from said prior owner, wherein said secondary token is used to take ownership of said object in said file system protected by said primary token.

20. The method of claim 19, wherein said negative response is selected from the group consisting of:

silent, unexpected, and expected negative.