Browse Prior Art Database

Method of Quiescing File System Activity

IP.com Disclosure Number: IPCOM000124723D
Original Publication Date: 2005-May-04
Included in the Prior Art Database: 2005-May-04
Document File: 1 page(s) / 53K

Publishing Venue

IBM

Abstract

Method for Quiescing File System Activity

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This is the abbreviated version, containing approximately 53% of the total text.

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Method of Quiescing File System Activity

Disclosed is an invention for quiescing file system activity prior to an unmount of a file system. A system using this design is ensured that no active references to objects in the file system are given out during the unmount. This could also provide benefits during maintenance or when bad behavior is detected by the file system.

    The Virtual File System (VFS) is an interface specification for the UNIX* file interface. The VFS interface provides abstract object, vnodes, which represent real objects in a file system. Vnodes can represent directories, files, FIFOs, sockets etc. Synchronizing the unmounting of a file system with acquiring of a new vnode for an object in the file system being unmounted has been a persistent problem. Let's call the acquiring of vnodes for a file system, vnode acquisition.

    One way to solve this problem is a complete interlock between unmounting any file system and the vnode acquisition for all file systems. However, this solution impacts file systems that have nothing to do with the file system being unmounted. A better solution would be to provide the capability to turn vnode acquisition on and off for a specific file system. The capability to shut off vnode acquisition for a particular file system could be used in other ways as well:

You need to do maintenance on your file system. Existing vnodes that are outstanding are acceptable, but you don't want to hand out any more because you're going to correct something or change the format of the vnode.

You detect possible bad behavior in the file system and want to limit its ability to cause more problems, so you turn...