Re: [PATCH 2/2] generic: test shutdowns of a nested filesystem

[Zorro Lang <zlang@redhat.com>]

On Tue, Aug 17, 2021 at 04:53:25PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
> 
> generic/475, but we're running fsstress on a disk image inside the
> scratch filesystem
> 
> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> ---

Good to me, thanks for this helpful test case. Just one question,
is it better to use xfs_metadump with "-o" option by default?

Reviewed-by: Zorro Lang <zlang@redhat.com>

>  common/rc             |   20 +++++++
>  tests/generic/725     |  136 +++++++++++++++++++++++++++++++++++++++++++++++++
>  tests/generic/725.out |    2 +
>  3 files changed, 158 insertions(+)
>  create mode 100755 tests/generic/725
>  create mode 100644 tests/generic/725.out
> 
> 
> diff --git a/common/rc b/common/rc
> index 84757fc1..473bfb0a 100644
> --- a/common/rc
> +++ b/common/rc
> @@ -631,6 +631,26 @@ _ext4_metadump()
>  		$DUMP_COMPRESSOR -f "$dumpfile" &>> "$seqres.full"
>  }
>  
> +# Capture the metadata of a filesystem in a dump file for offline analysis
> +_metadump_dev() {
> +	local device="$1"
> +	local dumpfile="$2"
> +	local compressopt="$3"
> +
> +	case "$FSTYP" in
> +	ext*)
> +		_ext4_metadump $device $dumpfile $compressopt
> +		;;
> +	xfs)
> +		_xfs_metadump $dumpfile $device none $compressopt
> +		;;
> +	*)
> +		echo "Don't know how to metadump $FSTYP"
> +		return 1
> +		;;
> +	esac
> +}
> +
>  _test_mkfs()
>  {
>      case $FSTYP in
> diff --git a/tests/generic/725 b/tests/generic/725
> new file mode 100755
> index 00000000..ac008fdb
> --- /dev/null
> +++ b/tests/generic/725
> @@ -0,0 +1,136 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2021 Oracle, Inc.  All Rights Reserved.
> +#
> +# FS QA Test No. 725
> +#
> +# Test nested log recovery with repeated (simulated) disk failures.  We kick
> +# off fsstress on a loopback filesystem mounted on the scratch fs, then switch
> +# out the underlying scratch device with dm-error to see what happens when the
> +# disk goes down.  Having taken down both fses in this manner, remount them and
> +# repeat.  This test simulates VM hosts crashing to try to shake out CoW bugs
> +# in writeback on the host that cause VM guests to fail to recover.
> +#
> +. ./common/preamble
> +_begin_fstest shutdown auto log metadata eio recoveryloop
> +
> +_cleanup()
> +{
> +	cd /
> +	$KILLALL_PROG -9 fsstress > /dev/null 2>&1
> +	wait
> +	if [ -n "$loopmnt" ]; then
> +		$UMOUNT_PROG $loopmnt 2>/dev/null
> +		rm -r -f $loopmnt
> +	fi
> +	rm -f $tmp.*
> +	_dmerror_unmount
> +	_dmerror_cleanup
> +}
> +
> +# Import common functions.
> +. ./common/dmerror
> +. ./common/reflink
> +
> +# Modify as appropriate.
> +_supported_fs generic
> +
> +_require_scratch_reflink
> +_require_cp_reflink
> +_require_dm_target error
> +_require_command "$KILLALL_PROG" "killall"
> +
> +echo "Silence is golden."
> +
> +_scratch_mkfs >> $seqres.full 2>&1
> +_require_metadata_journaling $SCRATCH_DEV
> +_dmerror_init
> +_dmerror_mount
> +
> +# Create a fs image consuming 1/3 of the scratch fs
> +scratch_freesp_bytes=$(_get_available_space $SCRATCH_MNT)
> +loopimg_bytes=$((scratch_freesp_bytes / 3))
> +
> +loopimg=$SCRATCH_MNT/testfs
> +truncate -s $loopimg_bytes $loopimg
> +_mkfs_dev $loopimg
> +
> +loopmnt=$tmp.mount
> +mkdir -p $loopmnt
> +
> +scratch_aliveflag=$tmp.runsnap
> +snap_aliveflag=$tmp.snapping
> +
> +snap_loop_fs() {
> +	touch "$snap_aliveflag"
> +	while [ -e "$scratch_aliveflag" ]; do
> +		rm -f $loopimg.a
> +		_cp_reflink $loopimg $loopimg.a
> +		sleep 1
> +	done
> +	rm -f "$snap_aliveflag"
> +}
> +
> +fsstress=($FSSTRESS_PROG $FSSTRESS_AVOID -d "$loopmnt" -n 999999 -p "$((LOAD_FACTOR * 4))")
> +
> +for i in $(seq 1 $((25 * TIME_FACTOR)) ); do
> +	touch $scratch_aliveflag
> +	snap_loop_fs >> $seqres.full 2>&1 &
> +
> +	if ! _mount $loopimg $loopmnt -o loop; then
> +		rm -f $scratch_aliveflag
> +		_metadump_dev $loopimg $seqres.loop.$i.md
> +		_fail "iteration $i loopimg mount failed"
> +		break
> +	fi
> +
> +	("${fsstress[@]}" >> $seqres.full &) > /dev/null 2>&1
> +
> +	# purposely include 0 second sleeps to test shutdown immediately after
> +	# recovery
> +	sleep $((RANDOM % (3 * TIME_FACTOR) ))
> +	rm -f $scratch_aliveflag
> +
> +	# This test aims to simulate sudden disk failure, which means that we
> +	# do not want to quiesce the filesystem or otherwise give it a chance
> +	# to flush its logs.  Therefore we want to call dmsetup with the
> +	# --nolockfs parameter; to make this happen we must call the load
> +	# error table helper *without* 'lockfs'.
> +	_dmerror_load_error_table
> +
> +	ps -e | grep fsstress > /dev/null 2>&1
> +	while [ $? -eq 0 ]; do
> +		$KILLALL_PROG -9 fsstress > /dev/null 2>&1
> +		wait > /dev/null 2>&1
> +		ps -e | grep fsstress > /dev/null 2>&1
> +	done
> +	for ((i = 0; i < 10; i++)); do
> +		test -e "$snap_aliveflag" || break
> +		sleep 1
> +	done
> +
> +	# Mount again to replay log after loading working table, so we have a
> +	# consistent fs after test.
> +	$UMOUNT_PROG $loopmnt
> +	_dmerror_unmount || _fail "iteration $i scratch unmount failed"
> +	_dmerror_load_working_table
> +	if ! _dmerror_mount; then
> +		_metadump_dev $DMERROR_DEV $seqres.scratch.$i.md
> +		_fail "iteration $i scratch mount failed"
> +	fi
> +done
> +
> +# Make sure the fs image file is ok
> +if [ -f "$loopimg" ]; then
> +	if _mount $loopimg $loopmnt -o loop; then
> +		$UMOUNT_PROG $loopmnt &> /dev/null
> +	else
> +		_metadump_dev $DMERROR_DEV $seqres.scratch.final.md
> +		echo "final scratch mount failed"
> +	fi
> +	SCRATCH_RTDEV= SCRATCH_LOGDEV= _check_scratch_fs $loopimg
> +fi
> +
> +# success, all done; let the test harness check the scratch fs
> +status=0
> +exit
> diff --git a/tests/generic/725.out b/tests/generic/725.out
> new file mode 100644
> index 00000000..ed73a9fc
> --- /dev/null
> +++ b/tests/generic/725.out
> @@ -0,0 +1,2 @@
> +QA output created by 725
> +Silence is golden.
>