#!/bin/sh
#
# checkarray -- initiates a check run of an MD array's redundancy information.
#
# Copyright © martin f. krafft <madduck@debian.org>
# distributed under the terms of the Artistic Licence 2.0
#
set -eu

PROGNAME=${0##*/}

about()
{
  echo "\
$PROGNAME -- MD array (RAID) redundancy checker tool
Copyright © martin f. krafft <madduck@debian.org>
Released under the terms of the Artistic Licence 2.0"
}

usage()
{
  about
  echo "
Usage: $PROGNAME [options] [arrays]

Valid options are:
 -a|--all	check all assembled arrays (ignores arrays in command line).
 -s|--status	print redundancy check status of devices.
 -x|--cancel	queue a request to cancel a running redundancy check.
 -i|--idle	perform check in a lowest scheduling class (idle)
 -l|--slow	perform check in a lower-than-standard scheduling class
 -f|--fast	perform check in higher-than-standard scheduling class
 --realtime	perform check in real-time scheduling class (DANGEROUS!)
 -c|--cron	honour AUTOCHECK setting in /etc/default/mdadm.
 -q|--quiet	suppress informational messages
		(use twice to suppress error messages too).
 -h|--help	show this output.
 -V|--version	show version information.

Examples:
 $PROGNAME --all --idle
 $PROGNAME --quiet /dev/md[123]
 $PROGNAME -sa
 $PROGNAME -x --all

Devices can be specified in almost any format. The following are equivalent:
 /dev/md0, md0, /dev/md/0, /sys/block/md0

You can also control the status of a check with /proc/mdstat file."
}

SHORTOPTS=achVqQsxilf
LONGOPTS=all,cron,help,version,quiet,real-quiet,status,cancel,idle,slow,fast,realtime

eval set -- $(getopt -o $SHORTOPTS -l $LONGOPTS -n $PROGNAME -- "$@")

arrays=''
cron=0
all=0
quiet=0
status=0
action=check
ionice=

for opt in $@; do
  case "$opt" in
    -a|--all) all=1;;
    -s|--status) action=status;;
    -x|--cancel) action=idle;;
    -i|--idle) ionice=idle;;
    -l|--slow) ionice=low;;
    -f|--fast) ionice=high;;
    --realtime) ionice=realtime;;
    -c|--cron) cron=1;;
    -q|--quiet) quiet=$(($quiet+1));;
    -Q|--real-quiet) quiet=$(($quiet+2));;	# for compatibility
    -h|--help) usage; exit 0;;
    -V|--version) about; exit 0;;
    /dev/md/*|md/*) arrays="${arrays:+$arrays }md${opt#*md/}";;
    /dev/md*|md*) arrays="${arrays:+$arrays }${opt#/dev/}";;
    /sys/block/md*) arrays="${arrays:+$arrays }${opt#/sys/block/}";;
    --) :;;
    *) echo "$PROGNAME: E: invalid option: $opt.  Try --help." >&2; exit 1;;
  esac
done

is_true()
{
  case "${1:-}" in
    [Yy]es|[Yy]|1|[Tt]rue|[Tt]) return 0;;
    *) return 1;
  esac
}

DEBIANCONFIG=/etc/default/mdadm
[ -r $DEBIANCONFIG ] && . $DEBIANCONFIG
if [ $cron = 1 ] && ! is_true ${AUTOCHECK:-false}; then
  [ $quiet -lt 1 ] && echo "$PROGNAME: I: disabled in $DEBIANCONFIG ." >&2
  exit 0
fi

if [ ! -f /proc/mdstat ]; then
  [ $quiet -lt 2 ] && echo "$PROGNAME: E: MD subsystem not loaded, or /proc unavailable." >&2
  exit 2
fi

if [ ! -d /sys/block ]; then
  [ $quiet -lt 2 ] && echo "$PROGNAME: E: /sys filesystem not available." >&2
  exit 7
fi

if [ -z "$(ls /sys/block/md* 2>/dev/null)" ]; then
  if [ $quiet -lt 2 ] && [ $cron != 1 ]; then
    echo "$PROGNAME: W: no active MD arrays found." >&2
    echo "$PROGNAME: W: (maybe uninstall the mdadm package?)" >&2
  fi
  exit 0
fi

if [ -z "$(ls /sys/block/md*/md/level 2>/dev/null)" ]; then
  [ $quiet -lt 2 ] && echo "$PROGNAME: E: kernel too old, no support for redundancy checks." >&2
  exit 6
fi

if ! egrep -q '^raid([1456]|10)$' /sys/block/md*/md/level 2>/dev/null; then
  [ $quiet -lt 1 ] && echo "$PROGNAME: I: no redundant arrays present; skipping checks..." >&2
  exit 0
fi

if [ -z "$(ls /sys/block/md*/md/sync_action 2>/dev/null)" ]; then
  [ $quiet -lt 2 ] && echo "$PROGNAME: E: no kernel support for redundancy checks." >&2
  exit 3
fi

[ $all = 1 ] && arrays="$(ls -d1 /sys/block/md* | cut -d/ -f4)"

for array in $arrays; do
  MDBASE=/sys/block/$array/md

  if [ ! -e $MDBASE/sync_action ]; then
    [ $quiet -lt 1 ] && echo "$PROGNAME: I: skipping non-redundant array $array." >&2
    continue
  fi

  cur_status="$(cat $MDBASE/sync_action)"

  if [ $action = status ]; then
    echo "$array: $cur_status"
    continue
  fi

  if [ ! -w $MDBASE/sync_action ]; then
    [ $quiet -lt 2 ] && echo "$PROGNAME: E: $MDBASE/sync_action not writeable." >&2
    exit 4
  fi

  if [ "$(cat $MDBASE/array_state)" = 'read-auto' ]; then
    [ $quiet -lt 1 ] && echo "$PROGNAME: W: array $array in auto-read-only state, skipping..." >&2
    continue
  fi

  case "$action" in
    idle)
      echo $action > $MDBASE/sync_action
      [ $quiet -lt 1 ] && echo "$PROGNAME: I: cancel request queued for array $array." >&2
      ;;

    check)
      if [ "$cur_status" != idle ]; then
        [ $quiet -lt 2 ] && echo "$PROGNAME: W: array $array not idle, skipping..." >&2
        continue
      fi

      # check if the array created recently and skip test if it is
      created=$(mdadm --detail /dev/$array 2>/dev/null |
                sed -n 's/.*Creation Time *://p' )
      if [ -n "$created" ]; then
        created=$(date +%s -d "$created" 2>/dev/null)
      fi
      if [ -n "$created" ]; then
        now=$(date +%s)
        if [ "$created" -lt "$now" -a \
             "$created" -gt "$(($now - 14 * 24 * 60 * 60))" ]; then
          [ $quiet -lt 2 ] && echo "$PROGNAME: I: array $array created recently, skipping..." >&2
          continue
        fi
      fi

      # queue request for the array. The kernel will make sure that these requests
      # are properly queued so as to not kill one of the array.
      echo $action > $MDBASE/sync_action
      [ $quiet -lt 1 ] && echo "$PROGNAME: I: check queued for array $array." >&2

      case "$ionice" in
        idle) ioarg='-c3'; renice=15;;
        low) ioarg='-c2 -n7'; renice=5;;
        high) ioarg='-c2 -n0'; renice=0;;
        realtime) ioarg='-c1 -n4'; renice=-5;;
        *) continue;;
      esac

      resync_pid= wait=5
      while [ $wait -gt 0 ]; do
        wait=$((wait - 1))
        resync_pid=$(ps -ef | awk -v dev=$array 'BEGIN { pattern = "^\\[" dev "_resync]$" } $8 ~ pattern { print $2 }')
        if [ -n "$resync_pid" ]; then
          [ $quiet -lt 1 ] && echo "$PROGNAME: I: selecting $ionice I/O scheduling class and $renice niceness for resync of $array." >&2
          ionice -p "$resync_pid" $ioarg 2>/dev/null || :
          renice -n $renice -p "$resync_pid" 1>/dev/null 2>&1 || :
          break
        fi
        sleep 1
      done
      ;;
  esac

done

exit 0