tools/dm-logwrite-replay

#!/bin/bash
# SPDX-License-Identifier: GPL-2.0 Copyright (c) 2021 Red Hat, Inc.  All Rights
# Reserved.
#
# dm-logwrite-replay utility.
#
# This is used to replay failures that result from generic/482. Modify the
# cleanup function in g/482 to the version that does not tear down the dm-thin
# volume and grab the thin volume name from the the 482.full output file.  Then
# you can replay the log writes manually with this tool so that the changes
# between a good replay and a bad replay can be isolated. The 482.full output
# file has all the FUA write locations recorded - these are what you pass the
# tool as "PREV_FUA" and "END_FUA".
#
# The tool uses the fstests infrastructure and scripts, so it needs to be run
# from the base fstests directory similar to the check script. RESULT_DIR is
# pointed at the current directory, which means that debug output from the tool
# placed in $seqres.full points ends up in ./dm-logwrite-replay.full.
#
# For example:
#	- device name /dev/mapper/thin-vol
# 	- last good replay @ write 124
# 	- first bad replay @ write 125
#
# Replay from start to 124:
#
# cd src/fstests
# tools/dm-logwrite-replay --dev /dev/mapper/thin-vol --end 124
# <take image of filesystem /dev/mapper/thin-vol>
#
# Replay from 124 to 125:
#
# tools/dm-logwrite-replay --dev /dev/mapper/thin-vol --start 124 --end 125
# <take image of filesystem from /dev/mapper/thin-vol>
#
# Now compare images of the filesystem to see the differences and analyse the
# failure.
#
# Often with log recovery failures, you need to see the pre-recovery state of
# the filesystem. To do this, use the --no-recovery option in conjunction with
# the above commands.  This allows you to determine if recovery is doing the
# wrong thing or not.
#
# Once finished, teardown the logwrites/thin vol with
#
# tools/dm-logwrite-replay --dev /dev/mapper/thin-vol --cleanup
#

DMTHIN_VOL_DEV=""
PREV_FUA=""
END_FUA=""
CLEANUP=""
DO_RECOVERY="y"

while [ $# -gt 0 ]; do
	case "$1" in
	--dev) DMTHIN_VOL_DEV="$2" ; shift ;;
	--start) PREV_FUA="$2" ; shift ;;
	--end) END_FUA="$2" ; shift ;;
	--cleanup) CLEANUP=y ;;
	--no-recovery) DO_RECOVERY="" ;;
	esac
	shift
done

[ -z "$DMTHIN_VOL_DEV" ] && _fail "not dmthin vol defined"

RESULT_DIR=`pwd`

. ./common/preamble
_begin_fstest replay

MOUNT_OPTIONS="-o dax=never"

# Import common functions.
. ./common/filter
. ./common/dmthin
. ./common/dmlogwrites

LOGWRITES_NAME=logwrites-test
LOGWRITES_DMDEV=/dev/mapper/$LOGWRITES_NAME

if [ -n "$CLEANUP" ]; then
	_log_writes_cleanup &> /dev/null
	_dmthin_cleanup
	exit;
fi

if [ -z "$PREV_FUA" ]; then
	prev=$(_log_writes_mark_to_entry_number mkfs)
	[ -z "$prev" ] && _fail "failed to locate entry mark 'mkfs'"
else
	prev="$((PREV_FUA + 1))"
fi
cur=$(_log_writes_find_next_fua $prev)
[ -z "$cur" ] && _fail "failed to locate next FUA write"

while [ ! -z "$cur" ]; do
	echo "Replay writes from $prev to $cur"
	_log_writes_replay_log_range $cur $DMTHIN_VOL_DEV

	if [ -n "$DO_RECOVERY" ]; then
		_dmthin_mount
		_dmthin_check_fs
	fi

	[ -n "$END_FUA" -a "$END_FUA" -eq "$cur" ] && break;

	prev=$cur
	cur=$(_log_writes_find_next_fua $(($cur + 1)))
	[ -z "$cur" ] && break
done