Conditional message delivery to holder of locks relating to a distributed locking manager

• US 20060248127A1
• Filed: 04/27/2005
• Published: 11/02/2006
• Est. Priority Date: 04/27/2005
• Status: Active Grant

• Current Assignee: Red Hat, Inc. (International Business Machines Corporation)
• Original Assignee: Red Hat, Inc. (International Business Machines Corporation)
• Inventors: Whitehouse, Steven John
• Granted Patent: US 7,484,048 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 9/526 Mutual exclusion algorithms

Abstract

A method of and system for managing storage resources in a distributed file system is described. A lock for a storage resource is maintained on a lock-holding node. A master node that controls the lock-holding node receives a lock request from a requesting node. The lock request includes a request to obtain a lock for the storage resource, and a request to perform an action by the lock-holding node on the storage resource if the request to obtain the lock is not granted immediately.

Claims

1. A method of managing storage resources in a distributed file system, the method comprising:

a) maintaining a first lock for a storage resource using a lock holder; and

b) receiving, at a master node that manages said lock-holder, a lock request from a requesting node, wherein said lock request includes;

b-i) a request to obtain a second lock for said storage resource, and

b-ii) a request for a node on which said lock holder resides to perform an action on said storage resource.

2. The method of claim 1, wherein the master node performs:

granting said second lock to said requesting node in response to said lock request in accordance with a mutual exclusion requirement of said first and second locks.

3. The method of claim 1, further comprising:

calculating a cost of releasing said first lock; and

calculating a cost of performing said requested action.

4. The method of claim 3, further comprising:

releasing said first lock if said cost of releasing said first lock is less than said cost of performing said requested action.

5. The method of claim 4, further comprising:

maintaining said first lock if said cost of performing said requested action is less than said cost of releasing said first lock.

6. The method of claim 5, further comprising:

performing said requested action without releasing said first lock.

7. The method of claim 1, further comprising:

identifying a node that accesses said resource most frequently; and

designating said identified node as said master node.

8. A system of clustered nodes that includes a file system for managing storage resources of the cluster, the system comprising:

a lock-holding node on which a first lock for a storage resource resides;

a lock-requesting node from which a lock request to release said lock is initiated; and

a master-lock node configured to receive said lock request from said lock-requesting node, wherein said lock request includes;

a) a request to obtain a second lock for said storage resource, and

b) a request for said lock-holding node to perform an action on said storage resource.

9. The system of claim 8, wherein said lock-holding node is configured to initiate calculations for determining a cost of releasing said first lock and a cost of performing said requested action.

10. The system of claim 9, wherein said lock-holding node is further configured to cause said first lock to be released from said lock-holding node if said cost of releasing said first lock is less than said cost of performing said requested action.

11. The system of claim 9, wherein said lock-holding node is further configured to cause said first lock to be maintained on said lock-holding node if said cost of performing said requested action is less than said cost of releasing said first lock.

12. The system of claim 8, wherein said master-lock node is configured to initiate calculations for determining a cost of releasing said first lock and a cost of performing said requested action.

13. The system of claim 12, wherein said master-lock node is further configured to cause said first lock to be released from said lock-holding node if said cost of releasing said first lock is less than said cost of performing said requested action.

14. The system of claim 12, wherein said master-lock node is further configured to cause said first lock to be maintained on said lock-holding node if said cost of performing said requested action is less than said cost of releasing said first lock.

15. The system of claim 9, further comprising a distributed lock manager configured to identify a node that accesses said resource most frequently and to designate said identified node as said master node.

16. The system of claim 9, wherein said lock-holding node is configured to perform said action without releasing said first lock.

17. A computer program product, residing on a computer-readable medium, the computer program product comprising computer instructions for configuring a computer to perform the acts of:

a) maintaining a first lock for a storage resource using a lock-holder; and

b) receiving, at a master node that controls said lock-holder, a lock request from a requesting node, wherein said lock request includes;

b-i) a request to obtain a second lock for said storage resource, and

b-ii) a request for a node on which said lock-holder resides to perform an action on said storage resource.

18. The medium of claim 17, further comprising instructions to configure said master node to:

grant said second lock to said requesting node in response to said lock request in accordance with a mutual exclusion requirement of said first and second locks.

19. The medium of claim 17, further comprising instructions for performing the acts of:

calculating an amount of input/output operations required to release said first lock;

calculating a frequency of said lock-holding node using said storage resource; and

calculating a cost of performing said requested action.

20. The medium of claim 19, further comprising instructions for performing the act of:

releasing said first lock if said cost of releasing said first lock is low said cost of performing said requested action.

21. The medium of claim 19, further comprising instructions for performing the act of:

maintaining said first lock if said cost of performing said requested action is lower than said cost of releasing said first lock.