Re: [PATCH 3/4] xfs/016: calculate minimum log size and end locations

[Eryu Guan <guaneryu@gmail.com>]

On Tue, Jun 18, 2019 at 02:07:21PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> xfs/016 looks for corruption in the log when the log wraps.  However,
> it hardcodes the minimum log size and the "95%" point where it wants to
> start the "nudge and check for corruption" part of the test.  New
> features require larger logs, which causes the test to fail when it
> can't mkfs with the smaller log size and when that 95% point doesn't put
> us within 20x "_log_traffic 2"s of the end of the log.
> 
> Fix the first problem by using the new min log size helper and replace
> the 95% figure with an estimate of where we need to be to guarantee that
> the 20x loop wraps the log.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

Call for reviews from other XFS folks :)

Thanks!

Eryu

> ---
>  tests/xfs/016     |   50 ++++++++++++++++++++++++++++++++++++++------------
>  tests/xfs/016.out |    1 +
>  2 files changed, 39 insertions(+), 12 deletions(-)
> 
> 
> diff --git a/tests/xfs/016 b/tests/xfs/016
> index 3407a4b1..aed37dca 100755
> --- a/tests/xfs/016
> +++ b/tests/xfs/016
> @@ -44,10 +44,21 @@ _block_filter()
>  
>  _init()
>  {
> +    echo "*** determine log size"
> +    local sz_mb=50
> +    local dsize="-d size=${sz_mb}m"
> +    local lsize="-l size=$(_scratch_find_xfs_min_logblocks $dsize)b"
> +    local force_opts="$dsize $lsize"
> +    _scratch_mkfs_xfs $force_opts >> $seqres.full 2>&1
> +
> +    # set log_size and log_size_bb globally
> +    log_size_bb=`_log_size`
> +    log_size=$((log_size_bb * 512))
> +    echo "log_size_bb = $log_size_bb log_size = $log_size" >> $seqres.full
> +
>      echo "*** reset partition"
> -    $here/src/devzero -b 2048 -n 50 -v 198 $SCRATCH_DEV
> +    $here/src/devzero -b 2048 -n $sz_mb -v 198 $SCRATCH_DEV # write 0xc6
>      echo "*** mkfs"
> -    force_opts="-dsize=50m -lsize=$log_size"
>      #
>      # Do not discard blocks as we check for patterns in free space.
>      # 
> @@ -65,6 +76,9 @@ _init()
>      . $tmp.mkfs
>      [ $logsunit -ne 0 ] && \
>          _notrun "Cannot run this test using log MKFS_OPTIONS specified"
> +
> +    # quotas generate extra log traffic so force it off
> +    _qmount_option noquota
>  }
>  
>  _log_traffic()
> @@ -157,6 +171,7 @@ _check_corrupt()
>  # get standard environment, filters and checks
>  . ./common/rc
>  . ./common/filter
> +. ./common/quota
>  
>  # real QA test starts here
>  _supported_fs xfs
> @@ -164,10 +179,6 @@ _supported_os Linux
>  
>  rm -f $seqres.full
>  
> -# mkfs sizes
> -log_size=3493888
> -log_size_bb=`expr $log_size / 512`
> -
>  _require_scratch
>  _init
>  
> @@ -188,18 +199,29 @@ echo "log sunit = $lsunit"			>>$seqres.full
>  [ $head -eq 2 -o $head -eq $((lsunit/512)) ] || \
>      _fail "!!! unexpected initial log position $head vs. $((lsunit/512))"
>  
> -# find how how many blocks per op for 100 ops
> +# find how how many blocks per op for 200 ops
>  # ignore the fact that it will also include an unmount record etc...
>  # this should be small overall
>  echo "    lots of traffic for sampling" >>$seqres.full
> -sample_size_ops=100
> +sample_size_ops=200
>  _log_traffic $sample_size_ops
>  head1=`_log_head`
>  num_blocks=`expr $head1 - $head`
>  blocks_per_op=`echo "scale=3; $num_blocks / $sample_size_ops" | bc`
> +echo "log position = $head1; old log position: $head" >> $seqres.full
>  echo "blocks_per_op = $blocks_per_op" >>$seqres.full
> -num_expected_ops=`echo "$log_size_bb / $blocks_per_op" | bc`
> +
> +# Since this is a log wrapping test, it's critical to push the log head to
> +# the point where it will wrap around within twenty rounds of log traffic.
> +near_end_min=$(echo "$log_size_bb - (10 * $blocks_per_op / 1)" | bc)
> +echo "near_end_min = $near_end_min" >>$seqres.full
> +
> +# Estimate the number of ops needed to get the log head close to but not past
> +# near_end_min.  We'd rather fall short and have to step our way closer to the
> +# end than run past the end.
> +num_expected_ops=$(( 8 * $(echo "$log_size_bb / $blocks_per_op" | bc) / 10))
>  echo "num_expected_ops = $num_expected_ops" >>$seqres.full
> +
>  num_expected_to_go=`echo "$num_expected_ops - $sample_size_ops" | bc`
>  echo "num_expected_to_go = $num_expected_to_go" >>$seqres.full
>  
> @@ -208,13 +230,17 @@ _log_traffic $num_expected_to_go
>  head=`_log_head`
>  echo "log position = $head"                     >>$seqres.full
>  
> -# e.g. 3891
> -near_end_min=`echo "0.95 * $log_size_bb" | bc | sed 's/\..*//'`
> -echo "near_end_min = $near_end_min" >>$seqres.full
> +# If we fell short of near_end_min, step our way towards it.
> +while [ $head -lt $near_end_min ]; do
> +	echo "    bump traffic from $head towards $near_end_min" >> $seqres.full
> +	_log_traffic 10 > /dev/null 2>&1
> +	head=$(_log_head)
> +done
>  
>  [ $head -gt $near_end_min -a $head -lt $log_size_bb ] || \
>      _fail "!!! unexpected near end log position $head"
>  
> +# Try to wrap the log, checking for corruption with each advance.
>  for c in `seq 0 20`
>  do
>      echo "   little traffic"            >>$seqres.full
> diff --git a/tests/xfs/016.out b/tests/xfs/016.out
> index f7844cdf..f4c8f88d 100644
> --- a/tests/xfs/016.out
> +++ b/tests/xfs/016.out
> @@ -1,4 +1,5 @@
>  QA output created by 016
> +*** determine log size
>  *** reset partition
>  Wrote 51200.00Kb (value 0xc6)
>  *** mkfs
>