Re: [PATCH V2] loosen input requirements on defrag testing

[Dmitry Monakhov <dmonakhov@openvz.org>]

Eric Sandeen <sandeen@sandeen.net> writes:

> We don't have perfect control of file allocation for these tests;
> in some cases we may fail to adequately fragment a file prior to
> defragmentation testing, and today that will fail the test.
>
> Attack this on 2 fronts:
>
> 1) Explicitly allow fewer extents on one of the input files in
>    generic/018 where the allocator has discretion.
> 2) _notrun rather than _fail if we don't create enough extents;
>    this is a defrag test, not an allocator/fragmentation test,
>    so just skip the test if we can't create an acceptable file
>    for defrag testing.
>
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>

> ---
>
> V2 fix args to _defrag and fix 018.out.  what the ... I swear I tested
> this... :/  This time for realz.
Looks reasonable.
Acked-by: Dmitry Monakhov <dmonakhov@openvz.org>

>
> diff --git a/common/defrag b/common/defrag
> index f923dc0..d2b137e 100644
> --- a/common/defrag
> +++ b/common/defrag
> @@ -53,15 +53,24 @@ _check_extent_count()
>  	max=$2
>  	ext_cnt=$3
>  
> -	[ "$min" -gt "$ext_cnt" ] && _fail "Found $ext_cnt extents  min:$max"
> -	[ "$max" -ne -1 ] && [ "$ext_cnt" -gt "$max" ] && _fail "Found $ext_cnt max: $max"
> +	# Return failure if $3 isn't between $1 and $2; let caller decide
> +	# action if it's not, we just return status here.
> +	if [ "$min" -gt "$ext_cnt" ]; then
> +		echo "Found $ext_cnt extents  min:$max"
> +		return 1;
> +	fi
> +	if [ "$max" -ne -1 ] && [ "$ext_cnt" -gt "$max" ]; then
> +		echo "Found $ext_cnt max: $max"
> +		return 1;
> +	fi
>  
>  	if [ $max -ne $min ]; then
>  	    echo "in_range($min, $max)"
>  	else
>  	    echo "$ext_cnt"
>  	fi
> -	return $ext_cnt
> +	# success
> +	return 0
>  }
>  
>  # Defrag file, check it, and remove it.
> @@ -129,6 +138,7 @@ _defrag()
>  	echo -n "Before: "
>  	ext_before=$(_extent_count $1)
>  	_check_extent_count $min_before $max_before $ext_before
> +	[ $? -eq 0 ] || _notrun "Could not adequately fragment file"
>  
>  	[ ! -z $csum ] && CSUM_BEFORE=`md5sum $1`
>  	STAT_BEFORE=`stat -c "a: %x m: %y c: %z" $1`
> @@ -141,6 +151,7 @@ _defrag()
>  	echo -n "After: "
>  	ext_after=$(_extent_count $1)
>  	_check_extent_count $min_after $max_after $ext_after
> +	[ $? -eq 0 ] || _fail "Failed to adequately defragment file"
>  
>  	[ "$ext_before" -lt "$ext_after" ] && \
>  		_fail "Number of extents increased after defragmentation," \
> diff --git a/tests/generic/018 b/tests/generic/018
> index d97bb88..e8dbab3 100755
> --- a/tests/generic/018
> +++ b/tests/generic/018
> @@ -77,7 +77,9 @@ for i in `seq 9 -1 0`; do
>  	$XFS_IO_PROG -fs -c "pwrite -b $bsize $((i * bsize)) $bsize" $fragfile \
>  					> /dev/null
>  done
> -_defrag --before 10 --after 1 $fragfile
> +
> +# Accept fewer fragments than we might expect; we don't have perfect control.
> +_defrag --max_before 10 --min_before 5 --after 1 $fragfile
>  
>  echo "Write backwards sync leaving holes - defrag should do nothing" | tee -a $seqres.full
>  for i in `seq 31 -2 0`; do
> diff --git a/tests/generic/018.out b/tests/generic/018.out
> index 5f265d1..1746b32 100644
> --- a/tests/generic/018.out
> +++ b/tests/generic/018.out
> @@ -9,7 +9,7 @@ Contiguous file:
>  Before: 1
>  After: 1
>  Write backwards sync, but contiguous - should defrag to 1 extent
> -Before: 10
> +Before: in_range(5, 10)
>  After: 1
>  Write backwards sync leaving holes - defrag should do nothing
>  Before: 16