Re: [PATCH v6 3/3] mkfs: make use of xfs_validate_stripe_geometry()

[Gao Xiang <hsiangkao@redhat.com>]

On Thu, Feb 18, 2021 at 10:38:17AM -0600, Eric Sandeen wrote:
> On 2/17/21 11:24 PM, Gao Xiang wrote:
> 

...

> since we have this check already in xfs_validate_stripe_geometry, it seems best to
> keep using it there, and not copy it ... which I think you accomplish below.
> 
> >> btw, do we have some range test about these variables? I could rearrange the code
> >> snippet, but I'm not sure if it could introduce some new potential regression as well...
> >>
> >> Thanks,
> >> Gao Xiang
> > 
> > Or how about applying the following incremental patch, although the maximum dswidth
> > would be smaller I think, but considering libxfs_validate_stripe_geometry() accepts
> > dswidth in 64-bit bytes as well. I think that would be fine. Does that make sense?
> > 
> > I've confirmed "# mkfs/mkfs.xfs -f -d su=4097,sw=1 /dev/loop0" now report:
> > stripe unit (4097) must be a multiple of the sector size (512)
> > 
> > and xfs/191-input-validation passes now...
> > 
> > diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
> > index f152d5c7..80405790 100644
> > --- a/mkfs/xfs_mkfs.c
> > +++ b/mkfs/xfs_mkfs.c
> > @@ -2361,20 +2361,24 @@ _("both data su and data sw options must be specified\n"));
> >  			usage();
> >  		}
> 
> Just thinking through this... I think this is the right idea.
> 
> > -		dsunit  = (int)BTOBBT(dsu);
> > -		big_dswidth = (long long int)dsunit * dsw;
> > +		big_dswidth = (long long int)dsu * dsw;
> 
> dsu is in bytes; this would mean big_dswidth is now also in bytes...
> the original goal here, I think, is to not overflow the 32-bit superblock value
> for dswidth.

Yeah, agreed. Thanks for catching this.

> 
> >  		if (big_dswidth > INT_MAX) {
> >  			fprintf(stderr,
> >  _("data stripe width (%lld) is too large of a multiple of the data stripe unit (%d)\n"),
> >  				big_dswidth, dsunit);
> 
> so this used to test big_dswidth in BB (sectors); but now it tests in bytes.
> 
> Perhaps this should change to check and report sectors again:
> 
>   		if (BTOBBT(big_dswidth) > INT_MAX) {
>   			fprintf(stderr,
>   _("data stripe width (%lld) is too large of a multiple of the data stripe unit (%d)\n"),
>   				BTOBBT(big_dswidth), dsunit);
> 
> I think the goal is to not overflow the 32-bit on-disk values, which would be
> easy to do with "dsw" specified as a /multiplier/ of "dsu"
> 
> So I think that if we keep range checking the value in BB units, it will be
> OK.
> 
> >  			usage();
> >  		}
> > -		dswidth = big_dswidth;
> > -	}
> >  
> > -	if (!libxfs_validate_stripe_geometry(NULL, BBTOB(dsunit), BBTOB(dswidth),
> > -					     cfg->sectorsize, false))
> > +		if (!libxfs_validate_stripe_geometry(NULL, dsu, big_dswidth,
> > +						     cfg->sectorsize, false))
> > +			usage();
> > +
> > +		dsunit = BTOBBT(dsu);
> > +		dswidth = BTOBBT(big_dswidth);
> > +	} else if (!libxfs_validate_stripe_geometry(NULL, BBTOB(dsunit),
> > +			BBTOB(dswidth), cfg->sectorsize, false)) {
> >  		usage();
> > +	}
> Otherwise this looks reasonable to me; now it's basically:
> 
> 1) If we got geometry in bytes, validate them directly
> 2) If we got geometry in BB, convert to bytes, and validate
> 3) If we got no geometry, validate the device-reported defaults
> 

Ok, let me send the next version.

Thanks,
Gao Xiang

> Thanks,
> -Eric
> 
> >  	/* If sunit & swidth were manually specified as 0, same as noalign */
> >  	if ((cli_opt_set(&dopts, D_SUNIT) || cli_opt_set(&dopts, D_SU)) &&
> > 
>