Re: [PATCH 5/6] xfs_scrub: fix fractional reporting of single inodes

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

On Sat, Nov 10, 2018 at 12:15:49AM -0700, Allison Henderson wrote:
> 
> 
> On 11/9/18 5:45 PM, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@oracle.com>
> > 
> > When there are fewer than 1024 inodes in the filesystem, scrub reports
> > fractional inodes in its final report:
> > 
> > 35.2MiB data used;  5.0 inodes used.
> > 34.2MiB data found; 5.0 inodes found.
> > 5.0 inodes counted; 5.0 inodes checked.
> > 
> > Inodes are indivisible, so only report the fractional part when we have
> > a large enough number of inodes to perform a unit conversion:
> > 
> > 35.2MiB data used;  5 inodes used.
> > 34.2MiB data found; 5 inodes found.
> > 5 inodes counted; 5 inodes checked.
> > 
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > ---
> >   scrub/common.c |    5 ++++-
> >   scrub/common.h |    2 +-
> >   scrub/phase7.c |   34 ++++++++++++++++++----------------
> >   3 files changed, 23 insertions(+), 18 deletions(-)
> > 
> > 
> > diff --git a/scrub/common.c b/scrub/common.c
> > index 96b86a26..78afc4bf 100644
> > --- a/scrub/common.c
> > +++ b/scrub/common.c
> > @@ -200,10 +200,12 @@ auto_space_units(
> >   double
> >   auto_units(
> >   	unsigned long long	number,
> > -	char			**units)
> > +	char			**units,
> > +	int			*precision)
> >   {
> >   	if (debug > 1)
> >   		goto no_prefix;
> > +	*precision = 1;
> >   	if (number > 1000000000000ULL) {
> >   		*units = "T";
> >   		return number / 1000000000000.0;
> > @@ -220,6 +222,7 @@ auto_units(
> >   no_prefix:
> >   	*units = "";
> > +	*precision = 0;
> >   	return number;
> >   }
> > diff --git a/scrub/common.h b/scrub/common.h
> > index 5a43ac0c..e85a0333 100644
> > --- a/scrub/common.h
> > +++ b/scrub/common.h
> > @@ -62,7 +62,7 @@ debug_tweak_on(
> >   double timeval_subtract(struct timeval *tv1, struct timeval *tv2);
> >   double auto_space_units(unsigned long long kilobytes, char **units);
> > -double auto_units(unsigned long long number, char **units);
> > +double auto_units(unsigned long long number, char **units, int *precision);
> >   unsigned int scrub_nproc(struct scrub_ctx *ctx);
> >   unsigned int scrub_nproc_workqueue(struct scrub_ctx *ctx);
> > diff --git a/scrub/phase7.c b/scrub/phase7.c
> > index cac0c75a..504a6927 100644
> > --- a/scrub/phase7.c
> > +++ b/scrub/phase7.c
> > @@ -107,6 +107,7 @@ xfs_scan_summary(
> >   	unsigned long long		f_free;
> >   	bool				moveon;
> >   	bool				complain;
> > +	int				ip;
> >   	int				error;
> >   	/* Flush everything out to disk before we start counting. */
> > @@ -176,27 +177,27 @@ xfs_scan_summary(
> >   		if (used_rt || stat_rt) {
> >   			d = auto_space_units(used_data, &du);
> >   			r = auto_space_units(used_rt, &ru);
> > -			i = auto_units(used_files, &iu);
> > +			i = auto_units(used_files, &iu, &ip);
> >   			fprintf(stdout,
> > -_("%.1f%s data used;  %.1f%s realtime data used;  %.2f%s inodes used.\n"),
> > -					d, du, r, ru, i, iu);
> > +_("%.1f%s data used;  %.1f%s realtime data used;  %.*f%s inodes used.\n"),
> > +					d, du, r, ru, ip, i, iu);
> >   			d = auto_space_units(stat_data, &du);
> >   			r = auto_space_units(stat_rt, &ru);
> > -			i = auto_units(counted_inodes, &iu);
> > +			i = auto_units(counted_inodes, &iu, &ip);
> >   			fprintf(stdout,
> > -_("%.1f%s data found; %.1f%s realtime data found; %.2f%s inodes found.\n"),
> > -					d, du, r, ru, i, iu);
> > +_("%.1f%s data found; %.1f%s realtime data found; %.*f%s inodes found.\n"),
> > +					d, du, r, ru, ip, i, iu);
> 
> Just a suggestion:
> Is plumbing in the extra precision parameter really preferable to just doing
> something like (i == (int)i ? 0 : 1)  Or maybe a precision macro or
> something.

auto_units() is supposed to turn a big number into something more
human-friendly for display, so it's in charge of figuring out all the
formatting stuff (label, precision, unit converted number).  Better to
keep all that in a single function than open-code it everywhere.

--D

> 
> Otherwise looks fine.
> 
> Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
> >   		} else {
> >   			d = auto_space_units(used_data, &du);
> > -			i = auto_units(used_files, &iu);
> > +			i = auto_units(used_files, &iu, &ip);
> >   			fprintf(stdout,
> > -_("%.1f%s data used;  %.1f%s inodes used.\n"),
> > -					d, du, i, iu);
> > +_("%.1f%s data used;  %.*f%s inodes used.\n"),
> > +					d, du, ip, i, iu);
> >   			d = auto_space_units(stat_data, &du);
> > -			i = auto_units(counted_inodes, &iu);
> > +			i = auto_units(counted_inodes, &iu, &ip);
> >   			fprintf(stdout,
> > -_("%.1f%s data found; %.1f%s inodes found.\n"),
> > -					d, du, i, iu);
> > +_("%.1f%s data found; %.*f%s inodes found.\n"),
> > +					d, du, ip, i, iu);
> >   		}
> >   		fflush(stdout);
> >   	}
> > @@ -210,12 +211,13 @@ _("%.1f%s data found; %.1f%s inodes found.\n"),
> >   			_("checked inodes"))) {
> >   		double		i1, i2;
> >   		char		*i1u, *i2u;
> > +		int		i1p, i2p;
> > -		i1 = auto_units(counted_inodes, &i1u);
> > -		i2 = auto_units(ctx->inodes_checked, &i2u);
> > +		i1 = auto_units(counted_inodes, &i1u, &i1p);
> > +		i2 = auto_units(ctx->inodes_checked, &i2u, &i2p);
> >   		fprintf(stdout,
> > -_("%.1f%s inodes counted; %.1f%s inodes checked.\n"),
> > -				i1, i1u, i2, i2u);
> > +_("%.*f%s inodes counted; %.*f%s inodes checked.\n"),
> > +				i1p, i1, i1u, i2p, i2, i2u);
> >   		fflush(stdout);
> >   	}
> >