cleanup

#!/bin/bash

# © 2015–2016 Sebastián González
# http://www.apache.org/licenses/LICENSE-2.0

set -o errexit

this="$(realpath "$0")"
lib="$(dirname "$this")"
script="$(basename "$this")"

source "$lib/common.sh"
source "$lib/$script.sh"

usage() {
    cat >&2 <<EOF
Usage: $script <pool>

Removes old backups from snapshot pool <pool>.

Example: $script /var/backup/home
EOF
    exit 1
}

(( $# == 1 )) || usage

pool="$1"

use-pool "$pool"

delete-subvolumes() {
    while read subvolume; do
        local path="$pool/$subvolume"
        btrfs subvolume delete "$path" > /dev/null
        echo "Removed subvolume $path"
    done
}

#---[ Cleanup tasks ]---

# Delete empty subvolumes (usually created for testing).
find "$pool" -maxdepth 1 -type d -empty -print0 | \
    xargs -0 -n 1 -r btrfs subvolume delete | \
    sed -e "s/Delete subvolume[^:]*:[^']*'\([^']*\)'/Removed empty subvolume \1/g"

# Run cleanup filters.
if [ -d "$lib"/cleanup.d ]; then
    for filter in "$lib"/cleanup.d/*.sh; do
        subvolume-names "$pool" | (source "$filter") | delete-subvolumes
    done
fi