#!/bin/bash
[[ $UID -ne 0 ]] && exec sudo "$0"

trap 'echo -e "\nInterrupted!"; exit 1' INT TERM

die() {
    cat << EOF

  +----------------------+
  |  There were errors!  |
  +----------------------+

EOF
    exit 1
}

mapfile -t mountpoints < <(
    findmnt --types btrfs --nofsroot --noheading --output SOURCE |
        sort -u |
        while IFS= read -r device; do
            findmnt --source "$device" --output TARGET --noheading | head -1
        done
)

for mount in "${mountpoints[@]}"; do
    echo "=== Working on '$mount':"
    #for x in 0 1 5 10 20 30; do
    for x in 5; do
        echo "* Metadata balancing, usage=$x..."
        btrfs balance start -musage="$x" "$mount" || die
    done
    #for x in 0 1 5 10 20 30 40 50; do
    for x in 5 10; do
        echo "* Data balancing, usage=$x..."
        btrfs balance start -dusage="$x" "$mount" || die
    done
done