From: Dave Kleikamp Subject: Re: [RFC] Ext3 online defrag Date: Thu, 26 Oct 2006 09:40:41 -0500 Message-ID: <1161873641.4536.3.camel@kleikamp.austin.ibm.com> References: <20061025024257.GA23769@havoc.gtf.org> <20061025042753.GV8394166@melbourne.sgi.com> <20061025044844.GB32486@havoc.gtf.org> <20061025053823.GX8394166@melbourne.sgi.com> <20061025060142.GD32486@havoc.gtf.org> <20061025081137.GB8394166@melbourne.sgi.com> <20061025170052.GA19513@havoc.gtf.org> <20061026014020.GC8394166@melbourne.sgi.com> <20061026033316.GC27858@thunk.org> <20061026063648.GE8394166@melbourne.sgi.com> <20061026133737.GA31996@thunk.org> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: David Chinner , Jeff Garzik , Barry Naujok , "'Alex Tomas'" , "'Jan Kara'" , linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org Return-path: Received: from e4.ny.us.ibm.com ([32.97.182.144]:657 "EHLO e4.ny.us.ibm.com") by vger.kernel.org with ESMTP id S1423530AbWJZOkz (ORCPT ); Thu, 26 Oct 2006 10:40:55 -0400 To: Theodore Tso In-Reply-To: <20061026133737.GA31996@thunk.org> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Thu, 2006-10-26 at 09:37 -0400, Theodore Tso wrote: > On Thu, Oct 26, 2006 at 04:36:48PM +1000, David Chinner wrote: > > > > Remember, I'm not just talking about defrag - I'm talking about > > > > an interface that is actually useful to apps that might care > > > > about how data is laid out on disk but the applications writers > > > > don't know anyhting about how filesystem X or Y or Z is > > > > implemented. Putting the burden of learning about fileystem > > > > internals on application developers is not the correct solution. > > If all you want is something for applicaiton developers, about all you > can do is to tell the filesystem, "create the file so that it will be > quickly accessed after accessing this file or this directory". I > really don't see the point of having the application specify block > numbers if you're also claiming the applicaiton isn't going to know > anything about the filesystem layout --- or even the RAID layout of > the filesystem. I don't think it's at **all** useful to be > half-pregnant on this score. I think a utility such as a defragmenter should know about about the filesystem layout. I also think that it would be a good thing to have a consistent interface so that every filesystem isn't implementing a completely different one. -- David Kleikamp IBM Linux Technology Center