Re: [PATCH 0/5] mkfs: Configuration file defined options

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Thu, Oct 15, 2020 at 02:29:20PM +1100, Dave Chinner wrote:
> Version 2:
> 
> - "-c file=xxx" > "-c options=xxx"
> - split out constification into new patch
> - removed debug output
> - fixed some comments
> - added man page stuff
> 
> Hi Folks,
> 
> Because needing config files for mkfs came up yet again in
> discussion, here is a simple implementation of INI format config
> files. These config files behave identically to options specified on
> the command line - the do not change defaults, they do not override
> CLI options, they are not overridden by cli options.
> 
> Example:
> 
> $ echo -e "[metadata]\ncrc = 0" > foo
> $ mkfs/mkfs.xfs -N -c options=foo -d file=1,size=100m blah
> Parameters parsed from config file foo successfully
> meta-data=blah                   isize=256    agcount=4, agsize=6400 blks
>          =                       sectsz=512   attr=2, projid32bit=1
>          =                       crc=0        finobt=0, sparse=0, rmapbt=0
>          =                       reflink=0
> data     =                       bsize=4096   blocks=25600, imaxpct=25
>          =                       sunit=0      swidth=0 blks
> naming   =version 2              bsize=4096   ascii-ci=0, ftype=1
> log      =internal log           bsize=4096   blocks=853, version=2
>          =                       sectsz=512   sunit=0 blks, lazy-count=1
> realtime =none                   extsz=4096   blocks=0, rtextents=0
> $
> 
> And there's a V4 filesystem as specified by the option defined
> in the config file. If we do:
> 
> $ mkfs/mkfs.xfs -N -c options=foo -m crc=1 -d file=1,size=100m blah
> -m crc option respecified
> Usage: mkfs.xfs
> .....
> $
> 
> You can see it errors out because the CRC option was specified in
> both the config file and on the CLI.
> 
> There's lots of stuff we can do to make the conflict and respec
> error messages better, but that doesn't change the basic
> functionality of config file based mkfs options. To allow for future
> changes to the way we want to apply config files, I created a
> full option subtype for config files. That means we can add another
> option to say "apply config file as default values rather than as
> options" if we decide that is functionality that we want to support.
> 
> However, policy decisions like that are completely separate to the
> mechanism, so these patches don't try to address desires to ship
> "tuned" configs, system wide option files, shipping distro specific
> defaults in config files, etc. This is purely a mechanism to allow
> users to specify options via files instead of on the CLI.  No more,
> no less.
> 
> This has only been given a basic smoke testing right now (see above!
> :).  I need to get Darrick's tests from the previous round of config

This was in the v1 series; have you gotten Darrick's fstests to do more
substantial testing? ;)

--D

> file bikeshedding working in my test environment to do more
> substantial testing of this....
> 
> Cheers,
> 
> Dave.
> 
> 
> Dave Chinner (5):
>   build: add support for libinih for mkfs
>   mkfs: add initial ini format config file parsing support
>   mkfs: constify various strings
>   mkfs: hook up suboption parsing to ini files
>   mkfs: document config files in mkfs.xfs(8)
> 
>  configure.ac         |   3 +
>  doc/INSTALL          |   5 +
>  include/builddefs.in |   1 +
>  include/linux.h      |   2 +-
>  m4/package_inih.m4   |  20 ++++
>  man/man8/mkfs.xfs.8  | 113 +++++++++++++++++++--
>  mkfs/Makefile        |   2 +-
>  mkfs/xfs_mkfs.c      | 228 ++++++++++++++++++++++++++++++++++++++-----
>  8 files changed, 340 insertions(+), 34 deletions(-)
>  create mode 100644 m4/package_inih.m4
> 
> -- 
> 2.28.0
>