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 20:30:44 +0530 Message-ID: <201003112030.44605.knikanth@suse.de> References: <4B947393.2050002@kernel.org> <201003111927.24829.knikanth@suse.de> <472A4C80-30CE-4875-8073-F7E61659B6F0@mit.edu> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from cantor.suse.de ([195.135.220.2]:35641 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932424Ab0CKO7a (ORCPT ); Thu, 11 Mar 2010 09:59:30 -0500 In-Reply-To: <472A4C80-30CE-4875-8073-F7E61659B6F0@mit.edu> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Theodore Tso Cc: Damian Lukowski , "linux-ide@vger.kernel.org" , Jeff Garzik , Matthew Wilcox , "Martin K. Petersen" , James Bottomley , 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 19:58:11 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. > Yes. May be, just a simple but transparent device-mapper like mapping on top of the mis-aligned partition, to do the alignment. Then the file-system code need not change much. But Linux already has device-mapper and Linux will not be affected with mis- aligned partitions, when we use LVM. But the actual problem here is that partitioning tools might create partitions that wont allow other operating-systems to boot. So it might be enough, if the partitioning tools just create partitions with (mis-)alignment requirement for Windows. Thanks Nikanth