From 33eb0a20d1dfe75418f49c124480d212199779c7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marc=20W=C3=A4ckerlin?= <marc@dev0001.int.swisssign.net>
Date: Fri, 6 Oct 2017 15:42:51 +0200
Subject: [PATCH] initial

---
 README.md          | 13 ++++++--
 btrfs-snapshots.sh | 82 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 93 insertions(+), 2 deletions(-)
 create mode 100755 btrfs-snapshots.sh

diff --git a/README.md b/README.md
index 2591c9d..8575f2b 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,12 @@
-# btrfs-backup
+Use BTRFS Snapshots For Backups
+===============================
 
-Scripts for using btrfs snapshot feature in backups.
\ No newline at end of file
+Try: btrfs-snapshots.sh --help
+
+Setup daily btrfs snapshot of all mounted subvols in `/etc/fstab`:
+
+    sudo cp btrfs-snapshots.sh /etc/cron.daily/btrfs-snapshots
+
+If you want hourly bakups, just enter:
+
+    sudo cp btrfs-snapshots.sh /etc/cron.hourly/btrfs-snapshots
diff --git a/btrfs-snapshots.sh b/btrfs-snapshots.sh
new file mode 100755
index 0000000..d54f601
--- /dev/null
+++ b/btrfs-snapshots.sh
@@ -0,0 +1,82 @@
+#!/bin/bash -e
+
+BTRFS_VOLUMES=${BTRFS_VOLUMES:-$(awk '!/^#/ && $3=="btrfs" {print $2}' /etc/fstab | tr '\n' ' ' | sed 's, $,,')}
+TMP_MNT=${TMP_MNT:-/var/tmp/btrfs-backup}
+
+vols=()
+del=
+dryrun=0
+while test $# -gt 0; do
+    case "$1" in
+        (-h|--help) cat <<EOF
+$0 [OPTIONS]
+
+OPTIONS
+
+  -h, --help         show this help
+  -n, --dry-run      execute dry run, do not backup, just show commands
+  -p, --path <path>  add a path that contains a btrfs (sub-) volume
+                     (defaults to: ${BTRFS_VOLUMES})
+  -m, --mnt <path>   temporary mount point (default: ${TMP_MNT})
+
+not yet implemented:
+
+  -d, --del <days>   delete snapshots older than given number of days
+
+ENVIRONMENT
+
+  BTRFS_VOLUMES      specify all volume pathes (instead of -p)
+  TMP_MNT            temporary mount point (instead of -m)
+
+DESCRIPTION
+
+Creates a snapshot for all btrfs volumes specified. Snapshot is named
+from the subvol name or if there is no subvol, from the path by
+appending -snapshot-YYYY-MM-DD-HH-mm.
+
+EOF
+                    exit;;
+        (-n|--dry-run) dryrun=1;;
+        (-p|--path) shift; vols+=( "$1" );;
+        (-m|--mnt) shift; TMP_MNT="$1";;
+        (-d|--del) shift; del="$1";;
+        (*) echo "ERROR: unknown option $1, try $0 --help" 1>&2
+            exit 1;;
+    esac
+    if test $# -lt 1; then
+        echo "ERROR: missing argument, try $0 --help" 1>&2
+        exit 1
+    fi
+    shift
+done
+
+BTRFS_VOLUMES=${BTRFS_VOLUMES:-$(awk '!/^#/ && $3=="btrfs" {print $2}' /etc/fstab)}
+TMP_MNT=${TMP_MNT:-/var/tmp/btrfs-backup}
+
+test -d "${TMP_MNT}" || mkdir -p "${TMP_MNT}"
+for fs in ${BTRFS_VOLUMES}; do
+    device=$(mount | awk '$3=="'$fs'" && $5=="btrfs" {print $1}')
+    subvol=$(mount | awk '$3=="'$fs'" && $5=="btrfs" {split(substr($6, 2, length($6)-2), res, ","); for (r in res) {if (res[r]~/^subvol=/) {sub(/^subvol=/,"" , res[r]); print res[r]}}}')
+    if test -n "$subvol"; then
+        name=${subvol}
+    else
+        if test "$fs" = "/"; then
+            name="@root"
+        else
+            name=${fs#/}
+            name=${name%/}
+            name=${name//\//-}
+        fi
+    fi
+    target="${name}-snapshot-$(date +%Y-%m-%d-%H-%M)"
+    if test $dryrun -eq 1; then
+        echo btrfs subvolume snapshot "${TMP_MNT}${subvol}" "${TMP_MNT}/${target}"
+    else
+        if mount | grep -q " on $TMP_MNT type "; then
+            sudo umount "$TMP_MNT"
+        fi
+        sudo mount "$device" "$TMP_MNT"
+        sudo btrfs subvolume snapshot "${TMP_MNT}${subvol}" "${TMP_MNT}/${target}"
+        sudo umount "$TMP_MNT"
+    fi
+done