[LTP] [PATCH v3] zram01: Improve error detection

[Alexey Kodanev]

Hi Petr,

On 8/15/19 8:58 AM, Petr Vorel wrote:
> * TBROK when detected size is 0 (+ print dd stderr, if any)
> * TBROK if actually used memory is 0, this fixes division by 0:
> 
> Sometimes free reports no memory use by zram, which leads to division by 0:
> zram01 8 TINFO: zram used 0M, zram disk sizes 104857600M
> /opt/ltp/testcases/bin/zram01.sh: line 87: 100 * 104857600 / 0: division by 0 (error token is "0")
> 
> Suggested-by: Alexey Kodanev <alexey.kodanev@oracle.com>
> Signed-off-by: Petr Vorel <pvorel@suse.cz>
> ---
> Hi Alexey,
> 
> feel free to send your fix if this is not what you meant.
> 
> Kind regards,
> Petr
> 
> Changes v2->v3:
> * print last dd error (if any) only when $b -eq 0

Yes, that's what I meant :)

> 
> Changes v2->v3:
> * add TBROK when $b -eq 0
> * print last dd error, if any
> ---
> 
>  testcases/kernel/device-drivers/zram/zram01.sh | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/testcases/kernel/device-drivers/zram/zram01.sh b/testcases/kernel/device-drivers/zram/zram01.sh
> index b3ed5170d..c0d46ed75 100755
> --- a/testcases/kernel/device-drivers/zram/zram01.sh
> +++ b/testcases/kernel/device-drivers/zram/zram01.sh
> @@ -67,9 +67,13 @@ zram_fill_fs()
>  		while true; do
>  			dd conv=notrunc if=/dev/zero of=zram${i}/file \
>  				oflag=append count=1 bs=1024 status=none \
> -				> /dev/null 2>&1 || break
> +				2>err.txt || break
>  			b=$(($b + 1))
>  		done
> +		if [ $b -eq 0 ]; then
> +			[ -s err.txt ] && tst_resm TWARN "dd error: $(cat err.txt)"
> +			tst_brkm TBROK "cannot fill zram"
> +		fi
>  		tst_resm TINFO "zram$i can be filled with '$b' KB"
>  	done
>  
> @@ -82,6 +86,8 @@ zram_fill_fs()
>  		total_size=$(($total_size + $s))
>  	done
>  
> +	[ $used_mem -eq 0 ] && tst_brkm TBROK "no memory used by zram"
> +
>  	tst_resm TINFO "zram used ${used_mem}M, zram disk sizes ${total_size}M"
>  
>  	local v=$((100 * $total_size / $used_mem))
>