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Option on a filesystem open to disable journaling

IP.com Disclosure Number: IPCOM000200324D
Publication Date: 2010-Oct-05
Document File: 2 page(s) / 22K

Publishing Venue

The IP.com Prior Art Database

Abstract

Method for a file system to bypass Journaling for a specific file open.

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This is the abbreviated version, containing approximately 51% of the total text.

Page 01 of 2

Option on a filesystem open to disable journaling

File system Journaling is a common technique used by some physical file system to allow the file system to recover to a consistent meta data state after an unexpected crash or power outage. The file system will first write a Journal entry when changing file system meta data such a director entry or file allocation blocks. Since the meta data is written to the Journal a consistent file system state can be established on reboot using the Journal if the file system was mounted at the time of the crash. Without Journaling the file system must be repaired by walking the entire file system using an OS command such as fsck. This fsck command thus checks the file system consistency and repairs the file system. The drawback to Journaling is that for Journaling to work the Journal must first be written to persistent media for use in the event of a crash. At some point the file system will write the director entry or allocation block meta data to the file system persistent media. Since the meta data is in the Journal the file system does not need to wait on entry to be written to the file system persistent media. When a file system is mounted the Journal is checked to see if outstanding Journal entries exist. If an Journal entry exists on mount the Journal entry is flushed to the file system persistent media.

The proposed idea is to add an option to the open of a file. This option would bypass Journaling on the file for the duration of the open. One use of this option would be an application writing temporary files. A second use would be an application where the contents of the file are invalid until end of the processing for that file. The proposed idea would allow a program to open the file and bypass the overhead of Journaling on that f...