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 > > <shrug> Bikeshedding more, what if either option accepted either an > absolute path, or a file in $sysconfdir/etc/mkfs.xfs.d/ ? Let us recall that the reason for -c set in stone on /@sysconfigdir@/mkfs.xfs.d/ was to allow clean simple code. The MKFS_XFS_CONFIG is simply a comopromise to allow flexibility on a full path in case you cannot use the /@sysconfigdir@/mkfs.xfs.d/ directory. Supporting both remains simple. If we wanted to support what you suggest, if a user specified -c hoogah we'd have to treat multiple possibilities in code, increasing complexity: a) Did the user mean the hoogah in the present directory? b) Did the user mean hoogah in /@sysconfigdir@/mkfs.xfs.d/ Granted, if the user specified a -c /tmp/hoogah its clearer that the full path would be desirable. So, I think what you suggest makes sense provided we get rid of a) option and require only an alternative path *iff* the first character in the path is '/'. Does this work for all cases we wish to support a full path in? > And the -c > option can be specified once to override the environment variable / > builtin detaults? The -c option as-is in my patch series always overrides the environment variable, but it is currently always tied to /@sysconfigdir@/mkfs.xfs.d/. So if you specify both the -c wins. Its also why I implemented the reset feature / mechanism. Luis -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
