From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id q1SJs7lG214977 for ; Tue, 28 Feb 2012 13:54:08 -0600 Received: from busoni.debian.org (busoni.debian.org [140.211.15.34]) by cuda.sgi.com with ESMTP id FRE7u04hry8uMja5 (version=TLSv1 cipher=AES256-SHA bits=256 verify=NO) for ; Tue, 28 Feb 2012 11:54:06 -0800 (PST) Subject: Bug#661580: mkfs.xfs fails to detect correct sector size Resent-To: debian-bugs-dist@lists.debian.org Resent-Message-ID: From: Goswin von Brederlow References: <20120228074914.31280.78231.reportbug@frosties.localnet> <20120228091151.GA24717@infradead.org> Date: Tue, 28 Feb 2012 20:19:54 +0100 In-Reply-To: <20120228091151.GA24717@infradead.org> (Christoph Hellwig's message of "Tue, 28 Feb 2012 04:11:51 -0500") Message-ID: <87399ug3z9.fsf@frosties.localnet> MIME-Version: 1.0 Reply-To: Goswin von Brederlow , 661580@bugs.debian.org List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Christoph Hellwig Cc: Debian Bug Tracking System , Carlos Maiolino , 661580@bugs.debian.org, Goswin von Brederlow Christoph Hellwig writes: > Carlos, didn't you plan to look into this issue? > > Goswin, how do you determin that mkfs is still doing unaligned I/O > when forcing the large sevtor size? Once we set the sector size XFS > can't do I/O smaller than it. I'm writing a nbd-server that uses async IO via libaio (the linux kernel AIO interface). This has some alignment requirements so I set nbd to use a 4k blocksize and added asserts that all requests are page aligned (both offset and size of the request). That worked fine for dd and mkfs.ext4 but fails on mount in general or mkfs.xfs. So next I added a printf("WARNING: unaligned read/write") and handled unaligned access in the server to see how extensive the problem is. With ext4 I get ONE single read request of 512 Byte on mount and everything else properly 4k aligned. With xfs I get a ton of them. If you want I can add a log of the read/write requests a mkfs.xfs and mount generates. MfG Goswin _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs