Transactional File System

• US 20100042626A1
• Filed: 10/22/2009
• Published: 02/18/2010
• Est. Priority Date: 03/30/2000
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Miller, Thomas J., Atkinson, Robert G., Verma, Surendra
• Granted Patent: US 8,010,559 B2
• Time in Patent Office: Days
• US Class Current: N/A
• CPC Class Codes: G06F 16/1865 Transactional file systems
• CPC Class Codes: Y10S 707/959 Network
• CPC Class Codes: Y10S 707/99931 Database or file accessing
• CPC Class Codes: Y10S 707/99932 Access augmentation or optimizing
• CPC Class Codes: Y10S 707/99937 Sorting
• CPC Class Codes: Y10S 707/99938 Concurrency, e.g. lock management in shared database
• CPC Class Codes: Y10S 707/99942 Manipulating data structure, e.g. compression, compaction, compilation
• CPC Class Codes: Y10S 707/99944 Object-oriented database structure
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

A transactional file system wherein multiple file system operations may be performed as a transaction. An application specifies that file system-related operations are to be handled as a transaction, and the application is given a file handle associated with a transaction context. For file system requests associated with a transaction context, a file system component manages operations consistent with transactional behavior. Transactions over a network are facilitated. Remote files may be accessed within a transaction via a redirector protocol. A redirector on a client computer system communicates with an agent on a server computer system to relay and maintain transactional information on both systems.

Claims

1. A method for maintaining files on a computer system, comprising:

receiving a first request at a file system of a first computer system to perform a first file system operation thereon, the first request including data that indicates to the file system that the first request is associated with a transaction specified by a program;

detecting, at a redirector of the file system of the first computer system, that the first request corresponds to a remote file that is stored on a second computer system to which the first computer system is connected via a network;

redirecting the first request to an agent of a file system of the second computer system;

performing the first file system operation at the file system of the second computer system;

maintaining information within the file system of the second computer system indicating that the first file system operation is associated with the transaction; and

if the transaction commits, committing the first file system operation.

2. The method of claim 1 wherein the redirector communicates with the agent using a redirector protocol.

3. The method of claim 2 wherein the redirector protocol is one of SMB, Wev DAV, or NFS.

4. The method of claim 1 wherein the first file system operation is a request to open a file stored in the file system of the second computer system, and wherein the method further comprises:

the redirector marshalling a transaction object associated with the first request into a flat byte-stream and transmitting the flat byte-stream to the agent; and

the agent creating a transaction object in the file system of the second computer system to represent the transaction on the second computer system.

5. The method of claim 4 further comprising:

the file system of the second computer system enlisting the transaction with a transaction coordinator proxy on the second computer system.

6. The method of claim 1 wherein the first computer system maintains a cache of reads and writes associated with the transaction, and wherein the method further comprises:

the second computer system determining that the transaction is to commit; and

in response, notifying the first computer system to flush its cache to the second computer system.

7. The method of claim 6 further comprising:

the second computer system receiving the flushed cache from the first computer system; and

overwriting a portion of a cache stored at the second computer system to represent reads and writes associated with the transaction with the contents of the cache flushed from the first computer system.

8. The method of claim 1 wherein the first computer system maintains a cache of reads and writes associated with the transaction, and wherein the method further comprises:

the second computer system determining that the transaction is to abort, and in response, notifying the first computer system of the pending abort; and

the first computer system discarding its cache rather than flushing it to the second computer system.

9. The method of claim 8 wherein the first computer system discards its cache in response to being notified that a third computer system has opened the remote file concurrently with the transaction.

10. The method of claim 1 further comprising:

logging information corresponding to the first file system operation in at least one log.

11. A computer readable medium storing computer executable instruction which when executed by a processor perform acts for maintaining files on a computer system, comprising:

receiving a first request at a file system of a first computer system to perform a first file system operation thereon, the first request including data that indicates to the file system that the first request is associated with a transaction specified by a program;

detecting, at a redirector of the file system of the first computer system, that the first request corresponds to a remote file that is stored on a second computer system to which the first computer system is connected via a network;

redirecting the first request to an agent of a file system of the second computer system;

performing the first file system operation at the file system of the second computer system;

maintaining information within the file system of the second computer system indicating that the first file system operation is associated with the transaction; and

if the transaction commits, committing the first file system operation.

12. The computer storage medium of claim 11 wherein the redirector communicates with the agent using a redirector protocol.

13. The computer storage medium of claim 12 wherein the redirector protocol is one of SMB, Wev DAV, or NFS.

14. The computer readable medium of claim 11 wherein the first file system operation is a request to open a file stored in the file system of the second computer system, and wherein the method further comprises:

the redirector marshalling a transaction object associated with the first request into a flat byte-stream and transmitting the flat byte-stream to the agent; and

the agent creating a transaction object in the file system of the second computer system to represent the transaction on the second computer system.

15. The computer readable medium of claim 14 further comprising:

the file system of the second computer system enlisting the transaction with a transaction coordinator proxy on the second computer system.

16. The computer readable medium of claim 11 wherein the first computer system maintains a cache of reads and writes associated with the transaction, and wherein the method further comprises:

the second computer system determining that the transaction is to commit; and

in response, notifying the first computer system to flush its cache to the second computer system.

17. The computer readable medium of claim 16 further comprising:

the second computer system receiving the flushed cache from the first computer system; and

overwriting a portion of a cache stored at the second computer system to represent reads and writes associated with the transaction with the contents of the flushed cache received from the first computer system.

18. The computer readable medium of claim 11 wherein the first computer system maintains a cache of reads and writes associated with the transaction, and wherein the method further comprises:

the second computer system determining that the transaction is to abort, and in response, notifying the first computer system of the pending abort; and

the first computer system discarding its cache rather than flushing it to the second computer system.

19. The computer readable medium of claim 18 wherein the first computer system discards its cache in response to being notified that a third computer system has opened the remote file concurrently with the transaction.

20. A computing system comprising:

a first computer system comprising a processor and memory;

a second computer system comprising a processor and memory, wherein the first computer system is connected to the second computer system over a network, and wherein the first and second computer systems communicate over the network to perform the following method;

receiving a first request at a file system of the first computer system to perform a first file system operation thereon, the first request including data that indicates to the file system that the first request is associated with a transaction specified by a program;

detecting, at a redirector of the file system of the first computer system, that the first request corresponds to a remote file that is stored on the second computer system;

redirecting the first request to an agent of a file system of the second computer system;

performing the first file system operation at the file system of the second computer system;

maintaining information within the file system of the second computer system indicating that the first file system operation is associated with the transaction; and

if the transaction commits, committing the first file system operation.