From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nikanth Karthikesan Subject: Re: ATA 4 KiB sector issues. Date: Thu, 11 Mar 2010 20:35:26 +0530 Message-ID: <201003112035.26743.knikanth@suse.de> References: <4B947393.2050002@kernel.org> <472A4C80-30CE-4875-8073-F7E61659B6F0@mit.edu> <1268318374.2798.2.camel@mulgrave.site> Mime-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: Received: from cantor2.suse.de ([195.135.220.15]:38932 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932954Ab0CKPEI (ORCPT ); Thu, 11 Mar 2010 10:04:08 -0500 In-Reply-To: <1268318374.2798.2.camel@mulgrave.site> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: James Bottomley Cc: Theodore Tso , Damian Lukowski , "linux-ide@vger.kernel.org" , Jeff Garzik , Matthew Wilcox , "Martin K. Petersen" , Tejun Heo , lkml , Daniel Taylor , Mark Lord , "H. Peter Anvin" , hirofumi@mail.parknet.co.jp, Andrew Morton , Alan Cox , irtiger@gmail.com, aschnell@suse.de, jdelvare@suse.de On Thursday 11 March 2010 20:09:34 James Bottomley wrote: > On Thu, 2010-03-11 at 09:28 -0500, Theodore Tso wrote: > > On Mar 11, 2010, at 8:57 AM, Nikanth Karthikesan wrote: > > > I guess, what he meant was, to keep filesystem blocks aligned, even if > > > the partition is not. Say if the partition is mis-aligned by 512-bytes, > > > let the filesystem waste 4k-512bytes and keep it's blocks aligned. But > > > it might be a case of over-engineering, possibly requiring disk format > > > change. > > > > Ah, yes, I agree with you; that's probably what he meant. > > > > Sure, that's theoretically possible, but it would mean changing every > > single filesystem, and it would require a file system format change > > --- or at least a file system format extension. > > > > It would seem to be way easier to simply fix the partitioning tools to > > do the right thing, though. > > Actually, it's a layering violation. The filesystem shouldn't need to > probe the device layout ... particularly when there are complexities > like is it logical 512 or physical, and if logical 512 on 4k does it > have an offset exponent or not. > > We can transmit certain abstractions of information up the stack (like > stripe width for RAID arrays which should be the fs optimal write size), > but for this type of alignment, which can be completely solved at the > partition layer, the information should really stay there and the > filesystem should "just work". > Right. It would be layering violation and we have LVM to solve it already. The real problem, here is just that partitioning-tools should create partitions that can work with both XP as well as Windows7. May be distro installers, should ask the user which compatibility he needs. Thanks Nikanth