From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from ipmail05.adl6.internode.on.net ([150.101.137.143]:9239 "EHLO ipmail05.adl6.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751756AbcJPVse (ORCPT ); Sun, 16 Oct 2016 17:48:34 -0400 Date: Mon, 17 Oct 2016 08:15:45 +1100 From: Dave Chinner Subject: Re: [PATCH] generic/285: discover allocation size for NFS Message-ID: <20161016211545.GA14023@dastard> References: <883bff7d2f3123aeb461df1072f9930c3d0f063b.1476440892.git.bcodding@redhat.com> <20161016071752.GC17675@infradead.org> <0A92328A-9E9C-4D8D-AADF-F995369A3E40@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0A92328A-9E9C-4D8D-AADF-F995369A3E40@redhat.com> Sender: fstests-owner@vger.kernel.org To: Benjamin Coddington Cc: Christoph Hellwig , fstests@vger.kernel.org List-ID: On Sun, Oct 16, 2016 at 06:18:13AM -0400, Benjamin Coddington wrote: > On 16 Oct 2016, at 3:17, Christoph Hellwig wrote: > > > On Fri, Oct 14, 2016 at 06:28:37AM -0400, Benjamin Coddington wrote: > >> On NFS, try to discover the allocation size for the exported filesystem. > >> NFS st_blksize is optimized for the network, and will usually be much > >> larger than the allocation size of the exported filesystem, which may > >> trigger preallocation strategies in the exported filesystem causing the > >> seek tests here to fail. > > > > Is there a reason not to use your new evidence-based check for all > > file systems? > > Only that on the filesystems I've checked (ext4, xfs, btrfs, tmpfs) > st_blksize is correct, so trying to discover it is unnecessary. As I've said previously, mount options (e.g. -o largeio) can change what XFS reports in st_blksize such that it behaves like the NFS client... Cheers, Dave. -- Dave Chinner david@fromorbit.com