common/dmdelay

##/bin/bash
# SPDX-License-Identifier: GPL-2.0
# Copyright (c) 2016 Red Hat, Inc.  All Rights Reserved.
#
# common functions for setting up and tearing down a dmdelay device

DELAY_NONE=0
DELAY_READ=1

export DELAY_NAME="delay-test.$seq"

_init_delay()
{
	local BLK_DEV_SIZE=`blockdev --getsz $SCRATCH_DEV`
	DELAY_DEV=/dev/mapper/$DELAY_NAME
	DELAY_TABLE="0 $BLK_DEV_SIZE delay $SCRATCH_DEV 0 0"
	DELAY_TABLE_RDELAY="0 $BLK_DEV_SIZE delay $SCRATCH_DEV 0 10000 $SCRATCH_DEV 0 0"
	_dmsetup_create $DELAY_NAME --table "$DELAY_TABLE" || \
		_fatal "failed to create delay device"
}

_mount_delay()
{
	_scratch_options mount
	$MOUNT_PROG -t $FSTYP `_common_dev_mount_options` $SCRATCH_OPTIONS \
		$DELAY_DEV $SCRATCH_MNT
}

_unmount_delay()
{
	_unmount $SCRATCH_MNT
}

_cleanup_delay()
{
	# If dmsetup load fails then we need to make sure to do resume here
	# otherwise the umount will hang
	$DMSETUP_PROG resume $DELAY_NAME > /dev/null 2>&1
	_unmount $SCRATCH_MNT > /dev/null 2>&1
	_dmsetup_remove $DELAY_NAME
}

# _load_delay_table <table> [lockfs]
#
# This defaults to --nolockfs, which doesn't freeze_fs() before loading the new
# table
_load_delay_table()
{
	table="$DELAY_TABLE"
	[ $1 -eq $DELAY_READ ] && table="$DELAY_TABLE_RDELAY"

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

	# run a suspend/resume cycle to avoid excessive resume delays once a
	# delay is introduced below
	$DMSETUP_PROG suspend $suspend_opt $DELAY_NAME
	$DMSETUP_PROG resume $suspend_opt $DELAY_NAME

	$DMSETUP_PROG suspend $suspend_opt $DELAY_NAME
	[ $? -ne 0 ] && _fatal "failed to suspend delay-test"

	$DMSETUP_PROG load $DELAY_NAME --table "$table"
	[ $? -ne 0 ] && _fatal "failed to load table into delay-test"

	$DMSETUP_PROG resume $DELAY_NAME
	[ $? -ne 0 ] && _fatal  "failed to resume delay-test"
}