From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ipmail01.adl2.internode.on.net ([150.101.137.133]:40831 "EHLO ipmail01.adl2.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753838AbdHYBCj (ORCPT ); Thu, 24 Aug 2017 21:02:39 -0400 Date: Fri, 25 Aug 2017 11:01:55 +1000 From: Dave Chinner Subject: Re: Filesystem configuration parsers - (was: Re: [RESEND][PATCH] xfs: add online uevent for mount operation) Message-ID: <20170825010155.GK21024@dastard> References: <1503582115-37220-1-git-send-email-houtao1@huawei.com> <20170824171028.GF4796@magnolia> <20170824180441.GL27873@wotan.suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170824180441.GL27873@wotan.suse.de> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: "Luis R. Rodriguez" Cc: "Darrick J. Wong" , Hou Tao , linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jeff Mahoney , NeilBrown , Tso Ted , Dmitri Pal On Thu, Aug 24, 2017 at 08:04:41PM +0200, Luis R. Rodriguez wrote: > While all this is nice, I'm sure we're all aware of the dangers of setting > things in stone through sysfs, its likely already decided for the above > tunables, but adding a uevent *is* yet another layer of user interface > which userspace can *expect* and we should be certain we want this so > we won't regress userspace later. > > Just saying, we better damn be sure this is the way we want to go. I'm not sure what you are trying to warn us about? :/ These are events on an XFS specific kobj, it's not a generic VFS filesystem event we are generating here. It's no different from a hardware device generating it's own uevents to tell userspace something changed in the device. A quick grep would have told you that GFS2 already has it's own online/offline uevents (e.g. gfs2_online_uevent()), as does the DLM code. Orangefs seems to use quite a few of uevent notifications, too. So it's not like we're doing something controversial or unique here, nor something that locks us out of a non-existent VFS event notification mechanism. Please, talk all you want about a Grand Unified VFS Event Notification infrastructure and filesystem tool libraries, but please don't hijack an unrelated discussion to do it. Cheers, Dave. -- Dave Chinner david@fromorbit.com