From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from aserp2130.oracle.com ([141.146.126.79]:37988 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752918AbeEUPeO (ORCPT ); Mon, 21 May 2018 11:34:14 -0400 Date: Mon, 21 May 2018 08:33:54 -0700 From: "Darrick J. Wong" Subject: Re: [PATCH v2 5/5] mkfs.xfs: add configuration file parsing support using our own parser Message-ID: <20180521153354.GH23858@magnolia> References: <20180517192700.23457-1-mcgrof@kernel.org> <20180517192700.23457-6-mcgrof@kernel.org> <1f1e87df-aba5-e285-e3cb-820306f24f1c@sandeen.net> <20180518034600.GW23858@magnolia> <20180520001648.GN23861@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180520001648.GN23861@dastard> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Dave Chinner Cc: Eric Sandeen , "Luis R. Rodriguez" , linux-xfs@vger.kernel.org, jack@suse.com, jeffm@suse.com, okurz@suse.com, lpechacek@suse.com, jtulak@redhat.com On Sun, May 20, 2018 at 10:16:48AM +1000, Dave Chinner wrote: > On Thu, May 17, 2018 at 08:46:00PM -0700, Darrick J. Wong wrote: > > On Thu, May 17, 2018 at 10:24:13PM -0500, Eric Sandeen wrote: > > > On 5/17/18 2:27 PM, Luis R. Rodriguez wrote: > > > > You may want to stick to specific set of configuration options when > > > > creating filesystems with mkfs.xfs -- sometimes due to pure technical > > > > reasons, but some other times to ensure systems remain compatible as > > > > new features are introduced with older kernels, or if you always want > > > > to take advantage of some new feature which would otherwise typically > > > > be disruptive. > > > > > > > > This adds support for parsing a configuration file to override defaults > > > > parameters to be used for mkfs.xfs. > > > > > > > > We define an XFS configuration directory,/etc/mkfs.xfs.d/ and allow for > > > > different configuration files, if none is specified we look for the > > > > default configuration file, /etc/mkfs.xfs.d/default. You can override > > > > with -c. For instance, if you specify: > > > > > > > > mkfs.xfs -c experimental -f /dev/loop0 > > > > > > > > The file /etc/mkfs.xfs.d/experimental will be used as your configuration > > > > file. If you really need to override the full path of the configuration > > > > file you may use the MKFS_XFS_CONFIG environment variable. > > > > > > I'm swamped under a deadline at work this week so just commenting at a > > > very high level for now, but I'm curious; why use an env var vs > > > providing a full path for -c ? env vars always strike me as magic unexpected > > > behaviors. > > > > > > # mkfs.xfs -c /my/fancy/path/to/config > > > > > > seems much clearer than > > > > > > # export MKFS_XFS_CONFIG=/my/fancy/path/to/ > > > # mkfs.xfs -c config > > > > > > i.e. if a full path is specified use it, else use the config directory. > > > > > > Thoughts? > > > > In this case your choices are: > > MKFS_XFS_CONFIG=/my/fancy/path/to/config mkfs.xfs > > > > or: > > cp /my/fancy/path/to/config /etc/mkfs.xfs.d/hoogah > > mkfs.xfs -c hooga > > Sorry, why do we need to copy it to /etc/mkfs.xfs.d/? No particular reason, just showing off relative pathname interpretation. That could have been mkfs.xfs -c ../../my/fancy/path/to/config But that's kinda ugly. $sysconfdir seems to get set to /usr on my local builds, though I think dpkg overrides that back to /... :) > > Bikeshedding more, what if either option accepted either an > > absolute path, or a file in $sysconfdir/etc/mkfs.xfs.d/ ? > > I kinda assumed that config files could be located anywhere, but we > only searched the sysconfig path if it didn't point at a local > file... openat() semantics are fine enough with me, I think. --D > > Cheers, > > Dave. > > -- > Dave Chinner > david@fromorbit.com > -- > To unsubscribe from this list: send the line "unsubscribe linux-xfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html