Techniques For Improving The Reliability of File Systems

• US 20080168108A1
• Filed: 05/18/2007
• Published: 07/10/2008
• Est. Priority Date: 01/04/2007
• Status: Active Grant

• Current Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Original Assignee: Hitachi Global Storage Technologies Netherlands BV (Western Digital Corporation)
• Inventors: New, Richard M. H., Campello de Souza, Jorge, Le Moal, Damien C. D., Molaro, Donald Joseph
• Granted Patent: US 7,640,412 B2
• Time in Patent Office: Days
• US Class Current: 707/202
• CPC Class Codes: G06F 11/1435 using file system or storage system metadata
• CPC Class Codes: Y10S 707/99953 Recoverability

Abstract

A system for enhancing the reliability of file systems is provided. In particular embodiments, the system includes a data storage device that includes one or more journal blocks, one or more primary metadata blocks, and one or more mirror metadata blocks. The system also includes a file system that writes metadata to the one or more journal blocks before writing the metadata to both the one or more primary metadata blocks and to the one or more mirror metadata blocks.

Claims

1. A system for enhancing the reliability of file systems, the system comprising:

a data storage device that stores metadata, the data storage device comprising at least one journal block, at least one primary metadata block, and at least one mirror metadata block; and

a file system that writes metadata to the journal block before writing the metadata to the primary metadata block and to the mirror metadata block.

2. The system defined in claim 1 wherein the file system erases the metadata from the journal block after the file system successfully writes the metadata to the primary metadata block and to the mirror metadata block.

3. The system defined in claim 1 wherein the file system overwrites any corrupted metadata in the primary metadata block with uncorrupted metadata from the mirror metadata block.

4. The system defined in claim 1 wherein the file system reattempts to write the metadata from a copy of the metadata stored in the journal block if a given write operation to the primary metadata block or the mirror metadata block fails.

5. The system defined in claim 1 wherein the file system performs mirroring of metadata separate from any process involving mirroring of file data.

6. The system defined in claim 1 wherein the data storage device utilizes the at least one journal block in combination with any of the at least one primary metadata block and the at least one mirror metadata block during file system recovery.

7. A method for storing metadata in a data storage device, the method comprising:

writing metadata to at least one journal block of a data storage device; and

writing the metadata to at least one primary metadata block and to at least one mirror metadata block of the data storage device after the metadata has been successfully written to the journal block.

8. The method defined in claim 7 further comprising erasing the metadata from the journal block after the metadata has been successfully written to the primary metadata block and to the mirror metadata block.

9. The method defined in claim 7 further comprising overwriting any corrupted metadata in the primary metadata block with uncorrupted metadata from the mirror metadata block.

10. The method defined in claim 7 further comprising reattempting to write the metadata from a copy of the metadata stored in the journal block if a given write operation to the primary metadata block or the mirror metadata block fails.

11. The method defined in claim 7 further comprising generating an error report if a given write operation to the primary metadata block or the mirror metadata block fails.

12. The method defined in claim 7 further comprising mirroring of metadata separate from any process involving mirroring of file data.

13. The method defined in claim 7 further comprising using backup metadata in the at least one mirror metadata block as an alternative to primary metadata in the at least one primary metadata block if the primary metadata is corrupted.

14. The method defined in claim 7 further comprising utilizing the at least one journal block in combination with any of the at least one primary metadata block and the at least one mirror metadata block during file system recovery.

15. A computer system that comprises code for storing metadata in a data storage device, wherein the code is stored on a computer readable medium, the computer system comprising:

code for writing metadata to a journal block of a data storage device; and

code for writing the metadata to a primary metadata block and to a mirror metadata block of the data storage device after the metadata has been successfully written to the journal block.

16. The computer system defined in claim 15 further comprising code for erasing the metadata from the journal block after the metadata has been successfully written to the primary metadata block and to the mirror metadata block.

17. The computer system defined in claim 15 further comprising code for overwriting any corrupted metadata in the primary metadata block with uncorrupted metadata from the mirror metadata block.

18. The computer system defined in claim 15 further comprising code for reattempting to write the metadata from a copy of the metadata stored in the journal block if a given write operation to the primary metadata block or the mirror metadata block fails.

19. The computer system defined in claim 15 further comprising code for generating an error report if a given write operation to the primary metadata block or the mirror metadata block fails.

20. The computer system defined in claim 15 further comprising code for mirroring of metadata separate from any process involving mirroring of file data.