lots of updates, some t11 stuff

[distro-setup] / btrfsmaint

#!/bin/bash


[[ $EUID == 0 ]] || exec sudo -E "${BASH_SOURCE[0]}" "$@"

source /a/bin/errhandle/err

# inspired from
# https://github.com/kdave/btrfsmaintenance


# Man page says we could also use a range, i suppose it would be
# logical to use a pattern like 5..10 10..20,
# but I don't know if this would help us at all.
dusage="5 10"
musage="5"

e() {
  echo "cron: $*"
  if ! $dryrun; then
    "$@"
  fi
}

check-idle() {
  type -p xprintidle &>/dev/null || return 0
  export DISPLAY=:0
  # a hours, a movie could run that long.
  idle_limit=$((1000 * 60 * 60 * 2))
  idle_time=$idle_limit
  while read -r user; do
    new_idle_time=$(sudo -u $user xprintidle 2>/dev/null) ||:
    if [[ $new_idle_time && $new_idle_time -lt $idle_time ]]; then
      idle_time=$new_idle_time
    fi
  done < <(users | tr " " "\n" | sort -u)
  if (( idle_time < idle_limit )); then
    idle=false
  else
    idle=true
  fi
}

usage() {
  cat <<EOF
Usage: ${0##*/} [ARGS]
Do btrfs maintence or stop if xprintidle shows a user

force  Run regardless of user idle status on all disks.
check  Only check if an existing maintence should be cancelled due to
         nonidle user. Also, runs in a loop every 20 seconds for 10
         minutes.

Note: Uses util-linux getopt option parsing: spaces between args and
options, short options can be combined, options before args.
EOF
  exit $1
}


force=false
check=false
dryrun=false
if [[ $1 ]]; then
  case $1 in
    check)
      check=true
      ;;
    force)
      force=true
      ;;
    dryrun)
      dryrun=true
      ;;
    *)
      echo "$0: error: unexpected arg" >&2
      usage 1
      ;;
  esac
fi


main() {
  idle=true
  if ! $force; then
    check-idle
    if ! $check; then
      min=0
      max_min=300
      # When the cron kicks in, we may not be idle (physically sleeping) yet, so
      # wait.
      while ! $idle && (( min < max_min )); do
        min=$(( min + 1 ))
        sleep 60
        check-idle
      done
      # If we've waited a really long time for idle, just give up.
      if (( min == max_min )); then
        return
      fi
    fi
  fi


  fnd="findmnt --types btrfs --noheading"
  for x in $($fnd --output "SOURCE" --nofsroot | sort -u); do
    mnt=$($fnd --output "TARGET" --first-only --source $x)
    [[ $mnt ]] || continue

    #### begin look for diff in stats, eg: increasing error count ####

    # Only run for $check, since it runs in parallel to non-check, avoid
    # race condition.
    if $check; then
      tmp=$(mktemp)
      # if mnt is /, avoid making a buggy looking path
      stats_path=${mnt%/}/btrfs-dev-stats
      if [[ ! -e $stats_path ]]; then
        btrfs dev stats -c $mnt >$stats_path ||: # populate initial reading
      elif ! btrfs dev stats -c $mnt >$tmp; then
        if ! diff -q $stats_path $tmp; then
              exim -t <<EOF
From: root@$HOSTNAME.b8.nz
To: alerts@iankelling.org
Subject: btrfsmaintstop: btrfs dev stats -c $mnt

$(diff -u $stats_path $tmp)
EOF
          mv $stats_path $stats_path.1
          cat $tmp >$stats_path
        fi
      fi
      rm -f $tmp
    fi
    #### end look for diff in stats, eg: increasing error count ####

    if $check; then
      if ! $idle; then
        if $dryrun; then
          echo "$0: not idle. if this wasnt a dry run, btrfs scrub cancel $mnt"
        else
          btrfs scrub cancel $mnt &>/dev/null ||:
        fi
      fi
      continue
    fi

    # for comparing before and after balance.
    # the log is already fairly verbose, so commented.
    # e btrfs filesystem df $mnt
    # e df -H $mnt
    if btrfs filesystem df $mnt | grep -q "Data+Metadata"; then
      for usage in $dusage; do
        e ionice -c 3 btrfs balance start -dusage=$usage -musage=$usage $mnt
      done
    else
      e ionice -c 3 btrfs balance start -dusage=0 $mnt
      for usage in $dusage; do
        e ionice -c 3 btrfs balance start -dusage=$usage $mnt
      done
      e ionice -c 3 btrfs balance start -musage=0 $mnt
      for usage in $musage; do
        e ionice -c 3 btrfs balance start -musage=$usage $mnt
      done
    fi
    date=
    scrub_status=$(btrfs scrub status $mnt)
    if printf "%s\n" "$scrub_status" | grep -i '^status:[[:space:]]*finished$' &>/dev/null; then
      date=$(printf "%s\n" "$scrub_status" | sed -rn 's/^Scrub started:[[:space:]]*(.*)/\1/p')
    fi
    if [[ ! $date ]]; then
      # output from older versions, at least btrfs v4.15.1
      date=$(
        printf "%s\n" "$scrub_status" | \
          sed -rn 's/^\s*scrub started at (.*) and finished.*/\1/p'
          )
    fi
    if [[ $date ]]; then
      if $dryrun; then
        echo "$0: last scrub finish for $mnt: $date"
      fi
      date=$(date --date="$date" +%s)
      # if date is sooner than 60 days ago
      # the wiki recommends 30 days or so, but
      # I'm going with 60 days.
      if (( date > EPOCHSECONDS - 60*60*24*60 )); then
        if $dryrun; then
          echo "$0: skiping scrub of $mnt, last was $(( (EPOCHSECONDS - date) / 60/60/24 )) days ago, < 30 days"
        fi
        continue
      fi
    fi
    # -c 2 -n 4 is from btrfsmaintenance, does ionice
    e btrfs scrub start -Bd -c 2 -n 4 $mnt

    # We normally only do one disk since this is meant to be run while I sleep
    # and if we try to do all disks, we invariably end up doing a scrub still
    # after I've woken up. So, just do one per day.
    if ! $force; then
      return 0
    fi
  done
}

loop-main() {
  while true; do
    main
    sleep 60
  done
}

if $check; then
  loop-main
else
  main
fi