bin/146205: df(1) fails to display total space on a 100PB filesystem correctly

[Alexander Best]

On Mon Mar 21 11, Xin LI wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA256
> 
> Revised version, I have mistakenly understood the old code, which only
> keeps one digit after the dot.

with this patch running my example code with

int64_t bytes = 6007692009979824 * 1024;

returns "8E". with

int64_t bytes = 2007692009979824 * 1024;

however it returns "9E. this doesn't seem quite right.

> 
> Cheers,
> - -- 
> Xin LI <delphij at delphij.net>	http://www.delphij.net/
> FreeBSD - The Power to Serve!	       Live free or die
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> Index: humanize_number.c
> ===================================================================
> --- humanize_number.c	(revision 219842)
> +++ humanize_number.c	(working copy)
> @@ -47,8 +47,9 @@
>      const char *suffix, int scale, int flags)
>  {
>  	const char *prefixes, *sep;
> -	int	b, i, r, maxscale, s1, s2, sign;
> +	int	i, r, maxscale, s1, s2, sign;
>  	int64_t	divisor, max;
> +	int64_t quotient = bytes, reminder = 0;
>  	size_t	baselen;
>  
>  	assert(buf != NULL);
> @@ -88,11 +89,10 @@
>  		buf[0] = '\0';
>  	if (bytes < 0) {
>  		sign = -1;
> -		bytes *= -100;
> +		quotient = -quotient;
>  		baselen = 3;		/* sign, digit, prefix */
>  	} else {
>  		sign = 1;
> -		bytes *= 100;
>  		baselen = 2;		/* digit, prefix */
>  	}
>  	if (flags & HN_NOSPACE)
> @@ -109,7 +109,7 @@
>  
>  	if (scale & (HN_AUTOSCALE | HN_GETSCALE)) {
>  		/* See if there is additional columns can be used. */
> -		for (max = 100, i = len - baselen; i-- > 0;)
> +		for (max = 1, i = len - baselen; i-- > 0;)
>  			max *= 10;
>  
>  		/*
> @@ -117,29 +117,33 @@
>  		 * If there will be an overflow by the rounding below,
>  		 * divide once more.
>  		 */
> -		for (i = 0; bytes >= max - 50 && i < maxscale; i++)
> -			bytes /= divisor;
> +		for (i = 0; quotient > max && i < maxscale; i++) {
> +			reminder = quotient % divisor;
> +			quotient /= divisor;
> +		}
>  
>  		if (scale & HN_GETSCALE)
>  			return (i);
> -	} else
> -		for (i = 0; i < scale && i < maxscale; i++)
> -			bytes /= divisor;
> +	} else {
> +		for (i = 0; i < scale && i < maxscale; i++) {
> +			reminder = quotient % divisor;
> +			quotient /= divisor;
> +		}
> +	}
>  
>  	/* If a value <= 9.9 after rounding and ... */
> -	if (bytes < 995 && i > 0 && flags & HN_DECIMAL) {
> +	if (quotient == 9 && reminder < 950 && i > 0 && flags & HN_DECIMAL) {
>  		/* baselen + \0 + .N */
>  		if (len < baselen + 1 + 2)
>  			return (-1);
> -		b = ((int)bytes + 5) / 10;
> -		s1 = b / 10;
> -		s2 = b % 10;
> +		s1 = (int)quotient + (((int)reminder + 50) / 100);
> +		s2 = (((int)reminder + 50) / 10) % 10;
>  		r = snprintf(buf, len, "%d%s%d%s%s%s",
>  		    sign * s1, localeconv()->decimal_point, s2,
>  		    sep, SCALE2PREFIX(i), suffix);
>  	} else
>  		r = snprintf(buf, len, "%" PRId64 "%s%s%s",
> -		    sign * ((bytes + 50) / 100),
> +		    sign * (quotient + (reminder + 50) / 100),
>  		    sep, SCALE2PREFIX(i), suffix);
>  
>  	return (r);


-- 
a13x