Re: [PATCH 2/5] mkfs: print config file for a given mkfs configuration

["Darrick J. Wong" <djwong@kernel.org>]

On Thu, Sep 03, 2026 at 01:14:01PM +0200, Andrey Albershteyn wrote:
> On 2026-08-31 16:27:05, Darrick J. Wong wrote:
> > From: Darrick J. Wong <djwong@kernel.org>
> > 
> > Add a -c makecfg= switch to mkfs to emit a mkfs.xfs configuration file
> > documenting the user-visible filesystem featuresets of the configured
> > filesystem.  This can be used to emit default configuration files as we
> > do once a year for each LTS.
> > 
> > Note that geometry information is not written to the configuration file.
> > 
> > Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
> > ---
> >  libfrog/fsgeom.h       |    3 
> >  libfrog/fsgeom.c       |  376 ++++++++++++++++++++++++++++++++++++++++++++++++
> >  man/man8/mkfs.xfs.8.in |    6 +
> >  mkfs/xfs_mkfs.c        |   44 +++++-
> >  4 files changed, 428 insertions(+), 1 deletion(-)
> > 
> > ...
> > 
> > diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
> > index 74bbb677eee2b6..212e17a354d8be 100644
> > --- a/mkfs/xfs_mkfs.c
> > +++ b/mkfs/xfs_mkfs.c
> > @@ -61,6 +61,7 @@ enum {
> >  
> >  enum {
> >  	C_OPTFILE = 0,
> > +	C_MAKECFG,
> >  	C_MAX_OPTS,
> >  };
> >  
> > @@ -312,6 +313,7 @@ static struct opt_params copts = {
> >  	.name = 'c',
> >  	.subopts = {
> >  		[C_OPTFILE] = "options",
> > +		[C_MAKECFG] = "makecfg",
> >  		[C_MAX_OPTS] = NULL,
> >  	},
> >  	.subopt_params = {
> > @@ -319,6 +321,10 @@ static struct opt_params copts = {
> >  		  .conflicts = { { NULL, LAST_CONFLICT } },
> >  		  .defaultval = SUBOPT_NEEDS_VAL,
> >  		},
> > +		{ .index = C_MAKECFG,
> > +		  .conflicts = { { NULL, LAST_CONFLICT } },
> > +		  .defaultval = 1,
> > +		},
> >  	},
> >  };
> >  
> > @@ -1072,6 +1078,7 @@ struct cli_params {
> >  
> >  	char	*cfgfile;
> >  	char	*protofile;
> > +	char	*makecfg;
> >  
> >  	enum fsprop_autofsck autofsck;
> >  
> > @@ -1207,7 +1214,7 @@ usage( void )
> >  {
> >  	fprintf(stderr, _("Usage: %s\n\
> >  /* blocksize */		[-b size=num]\n\
> > -/* config file */	[-c options=xxx]\n\
> > +/* config file */	[-c options=xxx,makecfg=0|1]\n\
> 
> Shouldn't this be makecfg=xxx?

I think they all should be "=path" because they take file paths
specifically.  I'll amend this patch to change this to

/* config file */  [-c options=path,makecfg=path]\n\

> Otherwise, looks good to me
> Reviewed-by: Andrey Albershteyn <aalbersh@kernel.org>

Thanks for reviewing!  A Sashiko review (I can run that internally now)
generated some complaints about xfrog_write_mkfs_config not handling the
quota mkfs options on metadir filesystems, and that there are a couple
of V4 options that it should emit.  I'll resend the series with those
two pieces of new functionality.

--D

> -- 
> - Andrey
>