bpfire/src/scripts/repair-mdraid

#!/bin/bash
###############################################################################
#                                                                             #
# IPFire.org - A linux based firewall                                         #
# Copyright (C) 2022 IPFire Team  <info@ipfire.org>                           #
#                                                                             #
# This program is free software: you can redistribute it and/or modify        #
# it under the terms of the GNU General Public License as published by        #
# the Free Software Foundation, either version 3 of the License, or           #
# (at your option) any later version.                                         #
#                                                                             #
# This program is distributed in the hope that it will be useful,             #
# but WITHOUT ANY WARRANTY; without even the implied warranty of              #
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the               #
# GNU General Public License for more details.                                #
#                                                                             #
# You should have received a copy of the GNU General Public License           #
# along with this program.  If not, see <http://www.gnu.org/licenses/>.       #
#                                                                             #
###############################################################################
#
# This script is supposed to repair any broken RAID installations
# where the system has been booted from only one of the RAID devices
# without the software RAID being activated first.
#
# This script does as follows:
#
# * It tries to find an inactive RAID called "ipfire:0"
# * It will then destroy any devices that are still part of this RAID.
#   This is required because if the RAID is being assembled correctly,
#   data from the disk that has NOT been mounted will be replicated
#   back to the device that has been changed. That causes that any
#   data that has been written to the mounted disk will be lost.
#   To avoid this, we will partially destroy the RAID.
# * We will then erase any partition tables and destroy any filesystems
#   on the devices so that they do not get accidentially mounted again.
# * The system will then need to be rebooted where the RAID will be
#   mounted again in a degraded state which might take some extra
#   time at boot (the system stands still for about a minute).
# * After the system has been booted up correctly, we will re-add
#   the devices back to the RAID which will resync and the system
#   will be back to its intended configuration.

find_inactive_raid() {
	local status
	local device
	local arg
	local args

	while read -r status device args; do
		if [ "${status}" = "INACTIVE-ARRAY" ]; then
			for arg in ${args}; do
				case "${arg}" in
					name=ipfire:0)
						echo "${device}"
						return 0
						;;
				esac
			done
		fi
	done <<< "$(mdadm --detail --scan)"

	return 1
}

find_root() {
	local device
	local mp
	local fs
	local args

	while read -r device mp fs args; do
		if [ "${mp}" = "/" ]; then
			echo "${device:0:-1}"
			return 0
		fi
	done < /proc/mounts

	return 1
}

find_raid_devices() {
	local raid="${1}"

	local IFS=,

	local device
	for device in $(mdadm -v --detail --scan "${raid}" | awk -F= '/^[ ]+devices/ { print $2 }'); do
		echo "${device}"
	done

	return 0
}

destroy_everything() {
	local device="${1}"
	local part

	# Destroy the RAID superblock
	mdadm --zero-superblock "${device}"

	# Wipe the partition table
	wipefs -a "${device}"

	# Wipe any partition signatures
	for part in ${device}*; do
		wipefs -a "${part}"
	done
}

raid_rebuild() {
	local devices=( "$@" )

	cat > /etc/rc.d/rcsysinit.d/S99fix-raid <<EOF
#!/bin/bash

case "\${1}" in
	start)
		if [ -e "/dev/md/ipfire:0" ]; then
			for device in ${devices[@]}; do
				mdadm --add "/dev/md/ipfire:0" "\${device}"
			done

			# Delete this script
			rm "\${0}"
		fi
		;;
esac
EOF

	chmod a+x /etc/rc.d/rcsysinit.d/S99fix-raid
}

main() {
	local raid="$(find_inactive_raid)"

	# Nothing to do if no RAID device found
	if [ -z "${raid}" ]; then
		return 0
	fi

	echo "Fixing RAID ${raid}..."

	local root="$(find_root)"

	# Finding any devices in this RAID
	local devices=(
		$(find_raid_devices "${raid}")
	)

	# Stop the RAID
	mdadm --stop "${raid}" &>/dev/null

	# Destroy any useful data on all remaining RAID devices
	local device
	for device in ${devices[@]}; do
		# Skip root
		[ "${device}" = "${root}" ] && continue

		destroy_everything "${device}"
	done &>/dev/null

	# Re-add devices to the RAID
	raid_rebuild "${device}"

	return 0
}

main "$@" || return $?