#!/bin/bash

# Copyright (C) 2014-2017 Neil Brown <neilb@suse.de>

#

#

#    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 2 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.

#

#    Author: Neil Brown

#    Email: <neilb@suse.com>

# This script should be run periodically to automatically

# perform a 'check' on any md arrays.

#

# It supports a 'time budget' such that any incomplete 'check'

# will be checkpointed when that time has expired.

# A subsequent invocation can allow the 'check' to continue.

#

# Options are:

#   --continue    Don't start new checks, only continue old ones.

#   --duration    This is passed to "date --date=$duration" to find out

#		  when to finish

#

# To support '--continue', arrays are identified by UUID and the 'sync_completed'

# value is stored  in /var/lib/mdcheck/$UUID

# convert a /dev/md name into /sys/.../md equivalent

sysname() {

	set `ls -lLd $1`

	maj=${5%,}

	min=$6

	readlink -f /sys/dev/block/$maj:$min

}

args=$(getopt -o hcd: -l help,continue,duration: -n mdcheck -- "$@")

rv=$?

if [ $rv -ne 0 ]; then exit $rv; fi

eval set -- $args

cont=

endtime=

while [ " $1" != " --" ]

do

    case $1 in

	--help )

		echo >&2 'Usage: mdcheck [--continue] [--duration time-offset]'

		echo >&2 '  time-offset must be understood by "date --date"'

		exit 0

		;;

	--continue ) cont=yes ;;

	--duration ) shift; dur=$1

		endtime=$(date --date "$dur" "+%s")

		;;

    esac

    shift

done

shift

# We need a temp file occasionally...

tmp=/var/lib/mdcheck/.md-check-$$

trap 'rm -f "$tmp"' 0 2 3 15

# firstly, clean out really old state files

mkdir -p /var/lib/mdcheck

find /var/lib/mdcheck -name "MD_UUID*" -type f -mtime +180 -exec rm {} \;

# Now look at each md device.

cnt=0

for dev in /dev/md?*

do

	[ -e "$dev" ] || continue

	sys=`sysname $dev`

	if [ ! -f "$sys/md/sync_action" ]

	then # cannot check this array

		continue

	fi

	if [ "`cat $sys/md/sync_action`" != 'idle' ]

	then # This array is busy

		continue

	fi

	mdadm --detail --export "$dev" | grep '^MD_UUID=' > $tmp || continue

	source $tmp

	fl="/var/lib/mdcheck/MD_UUID_$MD_UUID"

	if [ -z "$cont" ]

	then

		start=0

		logger -p daemon.info mdcheck start checking $dev

	elif [ -z "$MD_UUID" -o ! -f "$fl" ]

	then

		# Nothing to continue here

		continue

	else

		start=`cat "$fl"`

		logger -p daemon.info mdcheck continue checking $dev from $start

	fi

	cnt=$[cnt+1]

	eval MD_${cnt}_fl=\$fl

	eval MD_${cnt}_sys=\$sys

	eval MD_${cnt}_dev=\$dev

	echo $start > $fl

	echo $start > $sys/md/sync_min

	echo check > $sys/md/sync_action

done

if [ -z "$endtime" ]

then

	exit 0

fi

while [ `date +%s` -lt $endtime ]

do

	any=

	for i in `eval echo {1..$cnt}`

	do

		eval fl=\$MD_${i}_fl

		eval sys=\$MD_${i}_sys

		if [ -z "$fl" ]; then continue; fi

		if [ "`cat $sys/md/sync_action`" != 'check' ]

		then

			eval MD_${i}_fl=

			rm -f $fl

			continue;

		fi

		read a rest < $sys/md/sync_completed

		echo $a > $fl

		any=yes

	done

	if [ -z "$any" ]; then exit 0; fi

	sleep 120

done

# We've waited, and there are still checks running.

# Time to stop them.

for i in `eval echo {1..$cnt}`

do

	eval fl=\$MD_${i}_fl

	eval sys=\$MD_${i}_sys

	eval dev=\$MD_${i}_dev

	if [ -z "$fl" ]; then continue; fi

	if [ "`cat $sys/md/sync_action`" != 'check' ]

	then

		eval MD_${i}_fl=

		rm -f $fl

		continue;

	fi

	echo idle > $sys/md/sync_action

	cat $sys/md/sync_min > $fl

	logger -p daemon.info pause checking $dev at `cat $fl`

done