Concurrency classes for shared file systems

• US 7,254,578 B2
• Filed: 12/10/2002
• Issued: 08/07/2007
• Est. Priority Date: 12/10/2002
• Status: Expired due to Fees

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Devarakonda, Murthy V., Robinson, John T.
• Primary Examiner(s): Wong; Don
• Assistant Examiner(s): FILIPCZYK, MARCIN R
• Application Number:
  US10/315,820
• Publication Number:
  US 20040111422A1
• Time in Patent Office: 1,701 Days
• Field of Search: 707/1, 707/2, 707 7- 10, 707/200, 707/201, 707/6, 710/200
• US Class Current: 1/1
• CPC Class Codes: G06F 9/526 Mutual exclusion algorithms
• CPC Class Codes: Y10S 707/99931 Database or file accessing
• CPC Class Codes: Y10S 707/99938 Concurrency, e.g. lock management in shared database

Abstract

A method, apparatus and computer product wherein means and mechanisms are provided whereby, in a distributed or clustered shared file system, (1) concurrency classes may be defined specifying granularity of locking, whether locks are cached, and whether modified data is written-through at the completion of updates, (2) certain files, file types, or files and/or file types as used by given applications or classes of applications, may be associated with concurrency classes, and (3) for each usage of a file by an application, the associated concurrency class determines a policy for choosing specific concurrency and coherency control mechanisms to be used for accessing the given file.

Claims

1. In a distributed computer system with a shared file system, a method for managing concurrency and coherency of files, comprising:

defining a number of concurrency classes in a concurrency class table;

specifying files and applications to be associated with each concurrency class in a file/application concurrency class policy table; and

determining granularity of locking, caching of locks, and write-through of cached data, to a file server, policies to be used for files and applications in accordance with an associated concurrency class, wherein said concurrency classes include;

a default concurrency class in which granularity is at the file level, a cache lock is used, and there is no write-through;

a shared file concurrency class in which granularity is at the file level, a cache lock is used, and there is write-through;

an update file concurrency class in which granularity is at the file level, no cache lock is used, and there is write-through;

a default data concurrency class in which granularity is at the block level, a cache lock is used, and there is no write-through;

a shared data concurrency class in which granularity is at the block level, a cache lock is used, and there is write-through; and

an update data concurrency class in which granularity is at the block level, no cache lock is used, and there is write-through.

2. The method as recited in claim 1, wherein the concurrency class further specifies lifetime of cached locks.

3. The method as recited in claim 1, further comprising updating the concurrency table with a new concurrency class.

4. The method as recited in claim 1, further comprising defining an association between an item to be processed and a concurrency class.

5. The method as recited in claim 4, wherein the items processed comprise at least one of files, file types, files and/or file types, specified applications, and classes of applications.

6. The method as recited in claim 5, wherein an association table is accessed to determine said association.

7. The method as recited in claim 6, further comprising adding new associations to said association table.

8. The method as recited in claim 4, wherein when no association is defined for an item, a default concurrency class is used.

9. The method as recited in claim 4, wherein a factor to be considered in defining said association is an owner of the item, and a relationship between a party accessing the item and the owner.

10. The method as recited in claim 4, wherein a factor to be considered in defining said association is a party accessing the item, where a party is identified by a user identification and a group identification.

11. The method as recited in claim 1, wherein the file/application concurrency class policy table comprises indications that:

in the absence of a match in the file/application concurrency class policy table, and for all executable and documentation files, the default concurrency class is used;

for any other files having a match in the file/application concurrency class policy table and opened by a program, one of the update file, shared file, default data, shared data, and update data concurrency classes is used.

12. A computer system having at least one file server and a plurality of clients served by said at least one file server, wherein files provided by said at least one file server are shared by said clients, said system comprising:

a file manager for managing coherency and concurrency of the files, said file manager including;

a storage including a concurrency class table for defining a number of concurrency classes, and a file/application concurrency class policy table for specifying files and applications to be associated with each concurrency class; and

apparatus for execution of granularity of locking, caching of locks, and write-through of cached data, to a file server, policies to be used for files and applications in accordance with an associated concurrency class, wherein said concurrency classes include;

a default concurrency class in which granularity is at the file level, a cache lock is used, and there is no write-through;

a shared file concurrency class in which granularity is at the file level, a cache lock is used, and there is write-through;

an update file concurrency class in which granularity is at the file level, no cache lock is used, and there is write-through;

a default data concurrency class in which granularity is at the block level, a cache lock is used, and there is no write-through;

a shared data concurrency class in which granularity is at the block level, a cache lock is used, and there is write-through; and

an update data concurrency class in which granularity is at the block level, no cache lock is used, and there is write-through.

13. The system as recited in claim 12, wherein the concurrency class further specifies lifetime of cached locks.

14. The system as recited in claim 12, wherein said concurrency class table includes a default concurrency class in which granularity is at the file level, a cache lock is used and there is no write-through.

15. The system as recited in claim 12, further comprising a system management application for providing access to said storage for updating the concurrency table with a new concurrency class.

16. The system as recited in claim 12, further comprising additional storage for storing an association between an item to be processed and a concurrency class.

17. The system as recited in claim 16, wherein the items processed comprise at least one of files, file types, files and/or file types, specified applications, and classes of applications.

18. The system as recited in claim 17, wherein when no association is defined for an item, a default concurrency class is specified.

19. The system as recited in claim 16, wherein a factor to be considered in defining said association is an owner of the item, and a relationship between a party accessing the item and the owner.

20. The system as recited in claim 16, wherein a factor to be considered in defining said association is a party accessing the item, where a party is identified by a user identification and a group identification.

21. The system as recited in claim 16, comprising a system management application for accessing an association table to determine said association.

22. The system as recited in claim 21, further comprising a system management application for adding new associations to said association table.

23. The system as recited in claim 12, wherein the file/application concurrency class policy table comprises indications that:

in the absence of a match in the file/application concurrency class policy table, and for all executable and documentation files, the default concurrency class is used;

for any other files having a match in the file/application concurrency class policy table and opened by a program, one of the update file, shared file, default data, shared data, and update data concurrency classes is used.

24. An article of manufacture comprising a computer usable medium having computer readable program code means embodied therein for causing a computer to manage concurrency and coherency of files, said computer readable program code comprising:

code for defining a number of concurrency classes in a concurrency class table;

code for specifying files and applications to be associated with each concurrency class in a file/application concurrency class policy table; and

code for determining granularity of locking, caching of locks, and write-through of cached data, to a file server, policies to be used for files and applications in accordance with an associated concurrency class, wherein said concurrency classes include;

a default concurrency class in which granularity is at the file level, a cache lock is used, and there is no write-through;

a shared file concurrency class in which granularity is at the file level, a cache lock is used, and there is write-through;

an update file concurrency class in which granularity is at the file level, no cache lock is used, and there is write-through;

a default data concurrency class in which granularity is at the block level, a cache lock is used, and there is no write-through;

a shared data concurrency class in which granularity is at the block level, a cache lock is used, and there is write-through; and

an update data concurrency class in which granularity is at the block level, no cache lock is used, and there is write-through.

25. The article of manufacture as recited in claim 24, wherein the code for determining locking and caching policies further specifies lifetime of cached locks.

26. The article of manufacture as recited in claim 24, further comprising code for updating the concurrency table with a new concurrency class.

27. The article of manufacture as recited in claim 24, further comprising code for defining an association between an item to be processed and a concurrency class.

28. The article of manufacture as recited in claim 27, wherein the computer program code includes code for processing items which comprise at least one of files, file types, files and/or file types, specified applications, and classes of applications.

29. The article of manufacture as recited in claim 28, wherein the code for defining an association is an association table.

30. The article of manufacture as recited in claim 27, further comprising code for adding new associations to said association table.

31. The article of manufacture as recited in claim 27, wherein when no association is defined for an item, the computer readable program code defines a default concurrency class.

32. The article of manufacture as recited in claim 27, further comprising code for considering an owner of the item, and a relationship between a party accessing the item and the owner, in defining said association.

33. The article of manufacture as recited in claim 27, further comprising code for considering a party accessing the item, where a party is identified by a user identification and a group identification, in defining said association.

34. The article of manufacture as recited in claim 24, wherein the file/application concurrency class policy table comprises indications that:

in the absence of a match in the file/application concurrency class policy table, and for all executable and documentation files, the default concurrency class is used;

for any other files having a match in the file/application concurrency class policy table and opened by a program, one of the update file, shared file, default data, shared data, and update data concurrency classes is used.