From: "John Anthony Kazos Jr." Subject: Re: A feature?? Date: Sun, 20 May 2007 07:01:32 -0400 (EDT) Message-ID: References: <46500C02.3010802@cybericom.co.uk> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=us-ascii Cc: linux-ext4 To: Chris Lee Return-path: Received: from seahorse.shentel.net ([204.111.1.244]:32771 "EHLO seahorse.shentel.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755641AbXETL0E (ORCPT ); Sun, 20 May 2007 07:26:04 -0400 In-Reply-To: <46500C02.3010802@cybericom.co.uk> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org > I am not a FS guru so please tell me where to get off if I sound stupid. > After lurking for some time I have come up with something that may be of > interest as a feature: > > If EXT4 were to pr-allocate a configurable amount of space for a special file > and then use that file as a new EXT4 partition; > -Use that file for all new writes to disk > -Any changed files are changed by writing the change to this file, or the > whole changed file, whichever is more efficient end to end. > -A section of the file includes tracking of files that need modification in > the actual FS. > -Then when the disk is put back into normal read write mode the FS data in the > file just needs to be worked into the actual FS. > > This way the FS could be put into suspended operation while a third party > reads it. > I know there are other methods like snapshots, but this works at the FS level > so that the third party, which obviously needs to know ext4, can access the > hard drive directly. Sounds like a combination of loopback and union mounting, except more automated. Not sure there'd be much benefit to implementing those concepts redundantly at the filesystem level.