On Tue, Sep 10, 2019 at 11:32 AM Qu Wenruo <wqu@xxxxxxxx> wrote:
>
> We have generic dm-logwrites with fsstress test case (generic/482), but
> it doesn't cover fs specific operations like btrfs snapshot creation and
> deletion.
>
> Furthermore, that test is not heavy enough to bump btrfs tree height by
> its short runtime.
>
> And finally, btrfs check doesn't consider dirty log as an error, unlike
> ext*/xfs, that's to say we don't need to mount the fs to replay the log,
> but just running btrfs check on the fs is enough.
>
> So introduce a similar test case but for btrfs only.
>
> The test case will stress btrfs by:
> - Use small nodesize to bump tree height
> - Create a base tree which is already high enough
> - Trim tree blocks to find possible trim bugs
> - Call snapshot creation and deletion along with fsstress
>
> Also it includes certain workaround for btrfs:
> - Allow _log_writes_mkfs to accept extra mkfs options
> - Use no-holes feature
> To avoid missing hole file extents.
> Although that behavior doesn't follow the on-disk format spec, it
> doesn't cause data loss. And will follow the new on-disk format spec
> of no-holes feature, so it's better to workaround it.
>
> And an optimization for btrfs only:
> - Use replay-log --fsck/--check command
> Since dm-log-writes records bios sequentially, there is no way to
> locate certain entry unless we iterate all entries.
> This is becoming a big performance penalty if we replay certain a
> range, check the fs, then re-execute replay-log to replay another
> range.
>
> We need to records the previous entry location, or we need to
> re-iterate all previous entries.
>
> Thankfully, replay-log has already address it by providing --fsck and
> --check command, thus we don't need to break replay-log command.
>
> Please note, for fast storage (e.g. fast NVME or unsafe cache mode),
> it's recommended to use log devices larger than 15G, or we can't record
> the full log of just 30s fsstress run.
>
> Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
Reviewed-by: Filipe Manana <fdmanana@xxxxxxxx>
Looks good to me, thanks.
> ---
> For the log devices size problem, I have submitted dm-logwrites bio flag
> filter support, to filter out data bios.
>
> But that is not yet merged into kernel, thus we need a large log device
> for short run.
>
> For reference, if using unsafe cache mode for all test devices, on a
> system with 32G dual-channel DDR4 3200 RAM, 5G log device will be
> filled up in less than 15 seconds.
> So to ensure dm-log-writes covers all the operations, one needs at least
> 15G log device, and even more if using RAM with more channels.
>
> Changelog:
> v2
> - Better expression/words for comment
> - Add requirement for no-holes features
> - Use xattr to bump up tree height
> So no need for max_inline mount option
> - Coding style fixes for function definition
> - Add -f for rm to avoid user alias setting
> - Add new workload (update time stamp and create new files) for snapshot
> workload
> - Remove an unnecessary sync call
> - Get rid of wrong 2>&1 redirection
> - Add to group "snapshot" and "stress"
>
> v3:
> - Add '_require_attrs' and source common/attr
> - Introduce '_require_fsck_not_report_dirty_logs_as_error'
> - Add comment for the replay-log code fix
> - Wait after killing all background fsstress
> - Use $BLKDISCARD_PROG instead of plain 'blkdiscard'
> - Add trap for snapshot and delete workload
>
> v4:
> - Comment polishment
> - Remove unnecessary fix in replay-log
> - Catch the return value from replay-log properly
> - Move the fast log replay function local as it's only used by btrfs yet
> - Allow _log_writes_mkfs to accept extra options
> ---
> common/config | 1 +
> common/dmlogwrites | 2 +-
> tests/btrfs/192 | 175 ++++++++++++++++++++++++++++++++++++++++++++
> tests/btrfs/192.out | 2 +
> tests/btrfs/group | 1 +
> 5 files changed, 180 insertions(+), 1 deletion(-)
> create mode 100755 tests/btrfs/192
> create mode 100644 tests/btrfs/192.out
>
> diff --git a/common/config b/common/config
> index bd64be62..4c86a492 100644
> --- a/common/config
> +++ b/common/config
> @@ -183,6 +183,7 @@ export LOGGER_PROG="$(type -P logger)"
> export DBENCH_PROG="$(type -P dbench)"
> export DMSETUP_PROG="$(type -P dmsetup)"
> export WIPEFS_PROG="$(type -P wipefs)"
> +export BLKDISCARD_PROG="$(type -P blkdiscard)"
> export DUMP_PROG="$(type -P dump)"
> export RESTORE_PROG="$(type -P restore)"
> export LVM_PROG="$(type -P lvm)"
> diff --git a/common/dmlogwrites b/common/dmlogwrites
> index ae2cbc6a..2a7ff612 100644
> --- a/common/dmlogwrites
> +++ b/common/dmlogwrites
> @@ -69,7 +69,7 @@ _log_writes_mark()
> _log_writes_mkfs()
> {
> _scratch_options mkfs
> - _mkfs_dev $SCRATCH_OPTIONS $LOGWRITES_DMDEV
> + _mkfs_dev $SCRATCH_OPTIONS $@ $LOGWRITES_DMDEV
> _log_writes_mark mkfs
> }
>
> diff --git a/tests/btrfs/192 b/tests/btrfs/192
> new file mode 100755
> index 00000000..4414ee67
> --- /dev/null
> +++ b/tests/btrfs/192
> @@ -0,0 +1,175 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (C) 2019 SUSE Linux Products GmbH. All Rights Reserved.
> +#
> +# FS QA Test 192
> +#
> +# Test btrfs consistency after each FUA for a workload with snapshot creation
> +# and removal
> +#
> +seq=`basename $0`
> +seqres=$RESULT_DIR/$seq
> +echo "QA output created by $seq"
> +
> +here=`pwd`
> +tmp=/tmp/$$
> +status=1 # failure is the default!
> +trap "_cleanup; exit \$status" 0 1 2 3 15
> +
> +_cleanup()
> +{
> + cd /
> + kill -q $pid1 &> /dev/null
> + kill -q $pid2 &> /dev/null
> + "$KILLALL_PROG" -q $FSSTRESS_PROG &> /dev/null
> + wait
> + _log_writes_cleanup &> /dev/null
> + rm -f $tmp.*
> +}
> +
> +# get standard environment, filters and checks
> +. ./common/rc
> +. ./common/filter
> +. ./common/attr
> +. ./common/dmlogwrites
> +
> +# remove previous $seqres.full before test
> +rm -f $seqres.full
> +
> +# real QA test starts here
> +
> +# Modify as appropriate.
> +_supported_fs btrfs
> +_supported_os Linux
> +
> +_require_command "$KILLALL_PROG" killall
> +_require_command "$BLKDISCARD_PROG" blkdiscard
> +_require_btrfs_fs_feature "no_holes"
> +_require_btrfs_mkfs_feature "no-holes"
> +_require_log_writes
> +_require_scratch
> +_require_attrs
> +
> +# We require a 4K nodesize to ensure the test isn't too slow
> +if [ $(get_page_size) -ne 4096 ]; then
> + _notrun "This test doesn't support non-4K page size yet"
> +fi
> +
> +runtime=30
> +nr_cpus=$("$here/src/feature" -o)
> +# cap nr_cpus to 8 to avoid spending too much time on hosts with many cpus
> +if [ $nr_cpus -gt 8 ]; then
> + nr_cpus=8
> +fi
> +fsstress_args=$(_scale_fsstress_args -w -d $SCRATCH_MNT -n 99999 -p $nr_cpus \
> + $FSSTRESS_AVOID)
> +_log_writes_init $SCRATCH_DEV
> +
> +# Discard the whole devices so when some tree pointer is wrong, it won't point
> +# to some older valid tree blocks, so we can detect it.
> +$BLKDISCARD_PROG $LOGWRITES_DMDEV > /dev/null 2>&1
> +
> +# Use no-holes to avoid warnings of missing file extent items (expected
> +# for holes due to mix of buffered and direct IO writes).
> +# And use 4K nodesize to bump tree height.
> +_log_writes_mkfs -O no-holes -n 4k >> $seqres.full
> +_log_writes_mount
> +
> +$BTRFS_UTIL_PROG subvolume create $SCRATCH_MNT/src > /dev/null
> +mkdir -p $SCRATCH_MNT/snapshots
> +mkdir -p $SCRATCH_MNT/src/padding
> +
> +random_file()
> +{
> + local basedir=$1
> + echo "$basedir/$(ls $basedir | sort -R | tail -1)"
> +}
> +
> +snapshot_workload()
> +{
> + trap "wait; exit" SIGTERM
> +
> + local i=0
> + while true; do
> + $BTRFS_UTIL_PROG subvolume snapshot \
> + $SCRATCH_MNT/src $SCRATCH_MNT/snapshots/$i \
> + > /dev/null
> + # Do something small to make snapshots different
> + rm -f "$(random_file $SCRATCH_MNT/src/padding)"
> + rm -f "$(random_file $SCRATCH_MNT/src/padding)"
> + touch "$(random_file $SCRATCH_MNT/src/padding)"
> + touch "$SCRATCH_MNT/src/padding/random_$RANDOM"
> +
> + i=$(($i + 1))
> + sleep 1
> + done
> +}
> +
> +delete_workload()
> +{
> + trap "wait; exit" SIGTERM
> +
> + while true; do
> + sleep 2
> + $BTRFS_UTIL_PROG subvolume delete \
> + "$(random_file $SCRATCH_MNT/snapshots)" \
> + > /dev/null 2>&1
> + done
> +}
> +
> +# Replay and check each fua/flush (specified by $2) point.
> +#
> +# Since dm-log-writes records bio sequentially, even just replaying a range
> +# still needs to iterate all records before the end point.
> +# When number of records grows, it will be unacceptably slow, thus we need
> +# to use relay-log itself to trigger fsck, avoid unnecessary seek.
> +_log_writes_fast_replay_check()
> +{
> + local check_point=$1
> + local blkdev=$2
> + local fsck_command="$BTRFS_UTIL_PROG check $blkdev"
> + local ret
> +
> + [ -z "$check_point" -o -z "$blkdev" ] && _fail \
> + "check_point and blkdev must be specified for _log_writes_fast_replay_check"
> +
> + $here/src/log-writes/replay-log --log $LOGWRITES_DEV \
> + --replay $blkdev --check $check_point --fsck "$fsck_command" \
> + &> $tmp.full_fsck
> + ret=$?
> + tail -n 150 $tmp.full_fsck > $seqres.full
> + [ $ret -ne 0 ] && _fail "fsck failed during replay"
> +}
> +
> +xattr_value=$(printf '%0.sX' $(seq 1 3800))
> +
> +# Bumping tree height to level 2.
> +for ((i = 0; i < 64; i++)); do
> + touch "$SCRATCH_MNT/src/padding/$i"
> + $SETFATTR_PROG -n 'user.x1' -v $xattr_value "$SCRATCH_MNT/src/padding/$i"
> +done
> +
> +_log_writes_mark prepare
> +
> +snapshot_workload &
> +pid1=$!
> +delete_workload &
> +pid2=$!
> +
> +"$FSSTRESS_PROG" $fsstress_args > /dev/null &
> +sleep $runtime
> +
> +"$KILLALL_PROG" -q "$FSSTRESS_PROG" &> /dev/null
> +kill $pid1 &> /dev/null
> +kill $pid2 &> /dev/null
> +wait
> +_log_writes_unmount
> +_log_writes_remove
> +
> +_log_writes_fast_replay_check fua "$SCRATCH_DEV"
> +
> +echo "Silence is golden"
> +
> +# success, all done
> +status=0
> +exit
> diff --git a/tests/btrfs/192.out b/tests/btrfs/192.out
> new file mode 100644
> index 00000000..6779aa77
> --- /dev/null
> +++ b/tests/btrfs/192.out
> @@ -0,0 +1,2 @@
> +QA output created by 192
> +Silence is golden
> diff --git a/tests/btrfs/group b/tests/btrfs/group
> index 2474d43e..cab10d19 100644
> --- a/tests/btrfs/group
> +++ b/tests/btrfs/group
> @@ -194,3 +194,4 @@
> 189 auto quick send clone
> 190 auto quick replay balance qgroup
> 191 auto quick send dedupe
> +192 auto replay snapshot stress
> --
> 2.22.0
>
--
Filipe David Manana,
“Whether you think you can, or you think you can't — you're right.”
