On Thu, Feb 28, 2019 at 4:41 PM Brian Foster <bfoster@xxxxxxxxxx> wrote:
>
> The dm-log-writes replay mechanism issues discards to provide
> zeroing functionality to prevent out-of-order replay issues. These
> discards don't always result in zeroing bevavior, however, depending
> on the underlying physical device. In turn, this causes test
> failures on XFS v5 filesystems that enforce metadata log recovery
> ordering if the filesystem ends up with stale data from the future
> with respect to the active log at a particular recovery point.
>
> To ensure reliable discard zeroing behavior, use a thinly
> provisioned volume as the data device instead of using the scratch
> device directly. This slows the test down slightly, but provides
> reliable functional behavior at a reduced cost from active snapshot
> management or forced zeroing.
>
> Signed-off-by: Brian Foster <bfoster@xxxxxxxxxx>
Looks ok. Apart from minor nit below
Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx>
> ---
> tests/generic/482 | 20 ++++++++++++++------
> 1 file changed, 14 insertions(+), 6 deletions(-)
>
> diff --git a/tests/generic/482 b/tests/generic/482
> index 3c2199d7..3b93a7fc 100755
> --- a/tests/generic/482
> +++ b/tests/generic/482
> @@ -22,12 +22,14 @@ _cleanup()
> cd /
> $KILLALL_PROG -KILL -q $FSSTRESS_PROG &> /dev/null
> _log_writes_cleanup &> /dev/null
> + _dmthin_cleanup
> rm -f $tmp.*
> }
>
> # get standard environment, filters and checks
> . ./common/rc
> . ./common/filter
> +. ./common/dmthin
> . ./common/dmlogwrites
>
> # remove previous $seqres.full before test
> @@ -44,6 +46,7 @@ _require_command "$KILLALL_PROG" killall
> _require_scratch
_require_scratch_nocheck
> # and we need extra device as log device
> _require_log_writes
> +_require_dm_target thin-pool
>
>
> nr_cpus=$("$here/src/feature" -o)
> @@ -53,9 +56,15 @@ if [ $nr_cpus -gt 8 ]; then
> fi
> fsstress_args=$(_scale_fsstress_args -w -d $SCRATCH_MNT -n 512 -p $nr_cpus \
> $FSSTRESS_AVOID)
> +devsize=$((1024*1024*200 / 512)) # 200m phys/virt size
> +csize=$((1024*64 / 512)) # 64k cluster size
> +lowspace=$((1024*1024 / 512)) # 1m low space threshold
>
> +# Use a thin device to provide deterministic discard behavior. Discards are used
> +# by the log replay tool for fast zeroing to prevent out-of-order replay issues.
> _test_unmount
> -_log_writes_init $SCRATCH_DEV
> +_dmthin_init $devsize $devsize $csize $lowspace
> +_log_writes_init $DMTHIN_VOL_DEV
> _log_writes_mkfs >> $seqres.full 2>&1
> _log_writes_mark mkfs
>
> @@ -70,16 +79,15 @@ cur=$(_log_writes_find_next_fua $prev)
> [ -z "$cur" ] && _fail "failed to locate next FUA write"
>
> while [ ! -z "$cur" ]; do
> - _log_writes_replay_log_range $cur $SCRATCH_DEV >> $seqres.full
> + _log_writes_replay_log_range $cur $DMTHIN_VOL_DEV >> $seqres.full
>
> # Here we need extra mount to replay the log, mainly for journal based
> # fs, as their fsck will report dirty log as error.
> - # We don't care to preserve any data on $SCRATCH_DEV, as we can replay
> + # We don't care to preserve any data on the replay dev, as we can replay
> # back to the point we need, and in fact sometimes creating/deleting
> # snapshots repeatedly can be slower than replaying the log.
> - _scratch_mount
> - _scratch_unmount
> - _check_scratch_fs
> + _dmthin_mount
> + _dmthin_check_fs
>
> prev=$cur
> cur=$(_log_writes_find_next_fua $(($cur + 1)))
> --
> 2.17.2
>
