common/dmflakey

##/bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2013 Fusion IO, Inc.  All Rights Reserved.
#
# common functions for setting up and tearing down a dmflakey device

FLAKEY_ALLOW_WRITES=0
FLAKEY_DROP_WRITES=1
FLAKEY_ERROR_WRITES=2

export FLAKEY_NAME="flakey-test.$seq"
export FLAKEY_RTNAME="flakey-rttest.$seq"
export FLAKEY_LOGNAME="flakey-logtest.$seq"

_init_flakey()
{
	# Scratch device
	if [ -z "$NON_FLAKEY_DEV" ]; then
		# Set up the device switch
		local backing_dev="$SCRATCH_DEV"
		export NON_FLAKEY_DEV="$SCRATCH_DEV"
		SCRATCH_DEV=/dev/mapper/$FLAKEY_NAME
	else
		# Already set up; recreate tables
		local backing_dev="$NON_FLAKEY_DEV"
	fi
	local BLK_DEV_SIZE=`blockdev --getsz $backing_dev`
	FLAKEY_TABLE="0 $BLK_DEV_SIZE flakey $backing_dev 0 180 0"
	FLAKEY_TABLE_DROP="0 $BLK_DEV_SIZE flakey $backing_dev 0 0 180 1 drop_writes"
	FLAKEY_TABLE_ERROR="0 $BLK_DEV_SIZE flakey $backing_dev 0 0 180 1 error_writes"
	_dmsetup_create $FLAKEY_NAME --table "$FLAKEY_TABLE" || \
		_fatal "failed to create flakey device"

	# Realtime device
	if [ -n "$SCRATCH_RTDEV" ]; then
		if [ -z "$NON_FLAKEY_RTDEV" ]; then
			# Set up the device switch
			local backing_dev="$SCRATCH_RTDEV"
			export NON_FLAKEY_RTDEV="$SCRATCH_RTDEV"
			SCRATCH_RTDEV=/dev/mapper/$FLAKEY_RTNAME
		else
			# Already set up; recreate tables
			local backing_dev="$NON_FLAKEY_RTDEV"
		fi
		local BLK_DEV_SIZE=`blockdev --getsz $backing_dev`
		FLAKEY_RTTABLE="0 $BLK_DEV_SIZE flakey $backing_dev 0 180 0"
		FLAKEY_RTTABLE_DROP="0 $BLK_DEV_SIZE flakey $backing_dev 0 0 180 1 drop_writes"
		FLAKEY_RTTABLE_ERROR="0 $BLK_DEV_SIZE flakey $backing_dev 0 0 180 1 error_writes"
		_dmsetup_create $FLAKEY_RTNAME --table "$FLAKEY_RTTABLE" || \
			_fatal "failed to create flakey rt device"
	fi

	# External log device
	if [ -n "$SCRATCH_LOGDEV" ]; then
		if [ -z "$NON_FLAKEY_LOGDEV" ]; then
			# Set up the device switch
			local backing_dev="$SCRATCH_LOGDEV"
			export NON_FLAKEY_LOGDEV="$SCRATCH_LOGDEV"
			SCRATCH_LOGDEV=/dev/mapper/$FLAKEY_LOGNAME
		else
			# Already set up; recreate tables
			local backing_dev="$NON_FLAKEY_LOGDEV"
		fi
		local BLK_DEV_SIZE=`blockdev --getsz $backing_dev`
		FLAKEY_LOGTABLE="0 $BLK_DEV_SIZE flakey $backing_dev 0 180 0"
		FLAKEY_LOGTABLE_DROP="0 $BLK_DEV_SIZE flakey $backing_dev 0 0 180 1 drop_writes"
		FLAKEY_LOGTABLE_ERROR="0 $BLK_DEV_SIZE flakey $backing_dev 0 0 180 1 error_writes"
		_dmsetup_create $FLAKEY_LOGNAME --table "$FLAKEY_LOGTABLE" || \
			_fatal "failed to create flakey log device"
	fi
}

_cleanup_flakey()
{
	# If dmsetup load fails then we need to make sure to do resume here
	# otherwise the umount will hang
	test -n "$NON_FLAKEY_LOGDEV" && $DMSETUP_PROG resume $FLAKEY_LOGNAME &> /dev/null
	test -n "$NON_FLAKEY_RTDEV" && $DMSETUP_PROG resume $FLAKEY_RTNAME &> /dev/null
	test -n "$NON_FLAKEY_DEV" && $DMSETUP_PROG resume $FLAKEY_NAME &> /dev/null

	_unmount $SCRATCH_MNT > /dev/null 2>&1

	test -n "$NON_FLAKEY_DEV" && _dmsetup_remove $FLAKEY_NAME
	test -n "$NON_FLAKEY_LOGDEV" && _dmsetup_remove $FLAKEY_LOGNAME
	test -n "$NON_FLAKEY_RTDEV" && _dmsetup_remove $FLAKEY_RTNAME

	SCRATCH_DEV="$NON_FLAKEY_DEV"
	unset NON_FLAKEY_DEV

	if [ -n "$NON_FLAKEY_LOGDEV" ]; then
		SCRATCH_LOGDEV="$NON_FLAKEY_LOGDEV"
		unset NON_FLAKEY_LOGDEV
	fi

	if [ -n "$NON_FLAKEY_RTDEV" ]; then
		SCRATCH_RTDEV="$NON_FLAKEY_RTDEV"
		unset NON_FLAKEY_RTDEV
	fi
}

# _load_flakey_table <table> [lockfs]
#
# This defaults to --nolockfs, which doesn't freeze_fs() before loading the new
# table, so it simulates power failure.
_load_flakey_table()
{
	case "$1" in
	"$FLAKEY_DROP_WRITES")
		table="$FLAKEY_TABLE_DROP"
		logtable="$FLAKEY_LOGTABLE_DROP"
		rttable="$FLAKEY_RTTABLE_DROP"
		;;
	"$FLAKEY_ERROR_WRITES")
		table="$FLAKEY_TABLE_ERROR"
		logtable="$FLAKEY_LOGTABLE_ERROR"
		rttable="$FLAKEY_RTTABLE_ERROR"
		;;
	*)
		table="$FLAKEY_TABLE"
		logtable="$FLAKEY_LOGTABLE"
		rttable="$FLAKEY_RTTABLE"
		;;
	esac

	suspend_opt="--nolockfs"
	[ $# -gt 1 ] && [ $2 -eq 1 ] && suspend_opt=""

	# Suspend the scratch device before the log and realtime devices so
	# that the kernel can freeze and flush the filesystem if the caller
	# wanted a freeze.
	$DMSETUP_PROG suspend $suspend_opt $FLAKEY_NAME
	[ $? -ne 0 ] && _fatal "failed to suspend $FLAKEY_NAME"

	if [ -n "$NON_FLAKEY_RTDEV" ]; then
		$DMSETUP_PROG suspend $suspend_opt $FLAKEY_RTNAME
		[ $? -ne 0 ] && _fatal "failed to suspend flakey-rttest"
	fi

	if [ -n "$NON_FLAKEY_LOGDEV" ]; then
		$DMSETUP_PROG suspend $suspend_opt $FLAKEY_LOGNAME
		[ $? -ne 0 ] && _fatal "failed to suspend flakey-logtest"
	fi

	# There may be multiple dm targets in the table, and these dm targets
	# will be joined by the newline ("\n"). Option --table can not cope with
	# the multiple-targets case, so get them by reading from standard input.
	echo -e "$table" | $DMSETUP_PROG load $FLAKEY_NAME
	[ $? -ne 0 ] && _fatal "failed to load table into $FLAKEY_NAME"

	if [ -n "$NON_FLAKEY_RTDEV" ]; then
		echo -e "$rttable" | $DMSETUP_PROG load $FLAKEY_RTNAME
		[ $? -ne 0 ] && _fatal "failed to load table into flakey-rttest"
	fi

	if [ -n "$NON_FLAKEY_LOGDEV" ]; then
		echo -e "$logtable" | $DMSETUP_PROG load $FLAKEY_LOGNAME
		[ $? -ne 0 ] && _fatal "failed to load table into flakey-logtest"
	fi

	# Resume devices in the opposite order that we suspended them.
	if [ -n "$NON_FLAKEY_LOGDEV" ]; then
		$DMSETUP_PROG resume $FLAKEY_LOGNAME
		[ $? -ne 0 ] && _fatal  "failed to resume flakey-logtest"
	fi

	if [ -n "$NON_FLAKEY_RTDEV" ]; then
		$DMSETUP_PROG resume $FLAKEY_RTNAME
		[ $? -ne 0 ] && _fatal  "failed to resume flakey-rttest"
	fi

	$DMSETUP_PROG resume $FLAKEY_NAME
	[ $? -ne 0 ] && _fatal  "failed to resume $FLAKEY_NAME"
}

# Silently drop all writes and unmount/remount to simulate a crash/power
# failure.
_flakey_drop_and_remount()
{
	# If the full environment is set up, configure ourselves for shutdown
	type _prepare_for_eio_shutdown &>/dev/null && \
		_prepare_for_eio_shutdown $SCRATCH_DEV

	_load_flakey_table $FLAKEY_DROP_WRITES
	_scratch_unmount

	if [ "x$1" = "xyes" ]; then
		_check_scratch_fs
	fi

	_load_flakey_table $FLAKEY_ALLOW_WRITES
	_scratch_mount
}

_require_flakey_with_error_writes()
{
	local SIZE
	local TABLE
	local NAME=$FLAKEY_NAME

	_require_dm_target flakey

	SIZE=`blockdev --getsz $SCRATCH_DEV`
	TABLE="0 $SIZE flakey $SCRATCH_DEV 0 0 180 1 error_writes"

	_dmsetup_create $NAME --table "$TABLE" || \
		_notrun "This test requires error_writes feature in dm-flakey"

	_dmsetup_remove $FLAKEY_NAME
}