From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6D9E5C433EF for ; Wed, 8 Jun 2022 21:53:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230107AbiFHVxq (ORCPT ); Wed, 8 Jun 2022 17:53:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38688 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229492AbiFHVxq (ORCPT ); Wed, 8 Jun 2022 17:53:46 -0400 Received: from mail105.syd.optusnet.com.au (mail105.syd.optusnet.com.au [211.29.132.249]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 4AB361CFF2; Wed, 8 Jun 2022 14:53:45 -0700 (PDT) Received: from dread.disaster.area (pa49-181-2-147.pa.nsw.optusnet.com.au [49.181.2.147]) by mail105.syd.optusnet.com.au (Postfix) with ESMTPS id CA0DC10E755A; Thu, 9 Jun 2022 07:53:43 +1000 (AEST) Received: from dave by dread.disaster.area with local (Exim 4.92.3) (envelope-from ) id 1nz3cT-004Jeu-8P; Thu, 09 Jun 2022 07:53:41 +1000 Date: Thu, 9 Jun 2022 07:53:41 +1000 From: Dave Chinner To: =?iso-8859-1?Q?Lu=EDs?= Henriques Cc: fstests@vger.kernel.org, Jeff Layton , Xiubo Li , ceph-devel@vger.kernel.org Subject: Re: [PATCH 1/2] generic/020: adjust max_attrval_size for ceph Message-ID: <20220608215341.GU1098723@dread.disaster.area> References: <20220607151513.26347-1-lhenriques@suse.de> <20220607151513.26347-2-lhenriques@suse.de> <20220608001642.GS1098723@dread.disaster.area> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.4 cv=e9dl9Yl/ c=1 sm=1 tr=0 ts=62a11a68 a=ivVLWpVy4j68lT4lJFbQgw==:117 a=ivVLWpVy4j68lT4lJFbQgw==:17 a=8nJEP1OIZ-IA:10 a=JPEYwPQDsx4A:10 a=7-415B0cAAAA:8 a=j3QlSqe6CAlGx3RROSAA:9 a=wPNLvfGTeEIA:10 a=biEYGPWJfzWAr4FL6Ov7:22 Precedence: bulk List-ID: X-Mailing-List: fstests@vger.kernel.org On Wed, Jun 08, 2022 at 10:46:40AM +0100, Luís Henriques wrote: > On Wed, Jun 08, 2022 at 10:16:42AM +1000, Dave Chinner wrote: > > On Tue, Jun 07, 2022 at 04:15:12PM +0100, Luís Henriques wrote: > > > CephFS doesn't had a maximum xattr size. Instead, it imposes a maximum > > > size for the full set of an inode's xattrs names+values, which by default > > > is 64K but it can be changed by a cluster admin. > > > > So given the max attr name length is fixed by the kernel at 255 > > bytes (XATTR_NAME_MAX), that means the max value length is somewhere > > around 65000 bytes, not 1024 bytes? > > Right, but if the name is smaller (and in this test specifically we're not > using that XATTR_NAME_MAX), then that max value is > 65000. Or if the > file already has some attributes set (which is the case in this test), > then this maximum will need to be adjusted accordingly. (See below.) > > > Really, we want to stress and exercise max supported sizes - if the > > admin reduces the max size on their test filesystems, that's not > > something we should be trying to work around in the test suite by > > preventing the test code from ever exercising attr values > 1024 > > bytes..... > > Agreed. Xiubo also noted that and I also think this test shouldn't care > about other values. I should drop (or at least rephrase) the reference to > different values in the commit text. > > On Wed, Jun 08, 2022 at 04:41:25PM +0800, Xiubo Li wrote: > ... > > Why not fixing this by making sure that the total length of 'name' + 'value' > > == 64K instead for ceph case ? > > The reason why I didn't do that is because the $testfile *already* has > another attribute set when we set this max value: > > user.snrub="fish2\012" > > which means that the maximum for this case will be: > > 65536 - $max_attrval_namelen - strlen("user.snrub") - strlen("fish2\012") > > I'll split the _attr_get_max() function in 2: > > * _attr_get_max() sets max_attrs which is needed in several places in > generic/020 > * _attr_get_max_size() sets max_attrval_size, and gets called immediately > before that value is needed so that it can take into account the > current state. > > Does this sound reasonable? It seems like unnecessary additional complexity - keep it simple. Just set the max size for ceph to ~65000 and add a comment that says max name+val length for all ceph attrs is 64k and we need enough space of that space for two attr names... Cheers, Dave. -- Dave Chinner david@fromorbit.com