#!/usr/bin/bash
#
# Copyright (C) 2023 Red Hat, Inc. All rights reserved.
#
# This file is part of the device-mapper-multipath package.
#
# This copyrighted material is made available to anyone wishing to use,
# modify, copy, or redistribute it subject to the terms and conditions
# of the GNU General Public License v.2.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software Foundation,
# Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

unset PROGRAM FLUSH DEVICE DEVNAME MAJOR MINOR PATHDEVS PATHDEV HAVE_MULTIPATHD QUEUEING

function usage
{
	echo "usage: $PROGRAM [-h] [--flush] <device>"
	echo ""
	echo "remove a multipath device and its scsi path devices"
	echo ""
	echo "options:"
	echo "  -h, --help        show this help message and exit"
	echo "  --flush           disable queuing on the multipath device and"
	echo "                    flush the path devices before removing"
}

function parse_args
{
	while [ -n "$1" ]; do
		case $1 in
			--flush)
				FLUSH=1
				shift
				;;
			--help | -h)
				usage
				exit 1
				;;
			*)
				if [ -n "$DEVICE" ]; then
					usage
					exit 1
				fi
				DEVICE=$1
				shift
				;;
		esac
	done
}

function validate_device
{
	if [ -z "$DEVICE" ]; then
		usage
		exit 1
	fi
	if [[ "$DEVICE" =~ ^[[:digit:]]+:[[:digit:]]+$ ]]; then
		MAJOR=${DEVICE%%:*}
		MINOR=${DEVICE##*:}
		DEVNAME=`dmsetup ls --target multipath | grep "($MAJOR, $MINOR)$" | awk '{print $1}'`
	else
		DEVNAME=`dmsetup ls --target multipath | awk '{print $1}' | grep "^$DEVICE$"`
	fi
	if [ -z "$DEVNAME" ]; then
		DEVNAME=`multipath -v 1 -l $DEVICE 2>/dev/null`
		if [ -z "$DEVNAME" ]; then
			echo "$DEVICE is not a multipath device"
			exit 1
		fi
		# verify that this is not a native nvme multipath device
		dmsetup ls --target multipath | awk '{print $1}' | grep -q "^$DEVNAME$"
		if test $? -eq 1; then
			echo "$DEVICE is not a device-mapper multipath device"
			exit 1
		fi
	fi
	if [ -z "$MINOR" ]; then
		MINOR=`dmsetup info -c --noheadings -o minor $DEVNAME`
	fi
}

function get_paths
{
	PATHDEVS=`ls /sys/block/dm-$MINOR/slaves`
	for PATHDEV in $PATHDEVS; do
		if [[ ! "$PATHDEV" =~ ^sd[a-z]+$ ]]; then
			echo "$PATHDEV is not a scsi device. $PROGRAM only works with scsi devices"
			exit 1
		fi
	done
}

function remove_devs
{
	pidof multipathd > /dev/null
	HAVE_MULTIPATHD=$?
	multipath -v2 -l "$DEVNAME" | grep features | grep -q queue_if_no_path
	QUEUEING=$?
	if [ -n "$FLUSH" ] && [ "$QUEUEING" -eq 0 ]; then
		if test $HAVE_MULTIPATHD -eq 0; then
			multipathd disablequeueing map "$DEVNAME" > /dev/null
		else
			dmsetup message "$DEVNAME" 0 fail_if_no_path
		fi
		sleep 1
	fi
	if test $HAVE_MULTIPATHD -eq 0; then
		multipath -f "$DEVNAME"
	else
		multipathd -Df "$DEVNAME"
	fi
	if test $? -eq 1; then
		echo "$DEVICE cannot be removed"
		exit 1
	fi
	for PATHDEV in $PATHDEVS; do
		if [ -n "$FLUSH" ]; then
			blockdev --flushbufs /dev/"$PATHDEV"
		fi
		echo 1 > /sys/block/"$PATHDEV"/device/delete
	done
}

function verify_removal
{
	multipath -v 1 -d $DEVNAME | grep -q "^$DEVNAME$"
	if test $? -eq 0; then
		echo "$DEVICE removed but path devices still exist"
		exit 1
	fi
	multipath -v 1 -l $DEVNAME | grep -q "^$DEVNAME$"
	if test $? -eq 0; then
		echo "$DEVICE removal succeeded, but device still exists"
		exit 1
	fi
}

PROGRAM="$0"
parse_args "$@"
validate_device
get_paths
remove_devs
verify_removal