From 96c3420b4f7cf29e50328ad0e732c97233ed02b5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?marc=20W=C3=A4ckerlin?= <marc@waeckerlin.org>
Date: Fri, 27 Oct 2017 10:21:56 +0200
Subject: [PATCH] rebalance / defragment is optional

---
 btrfs-snapshots.sh | 18 +++++++++++++++---
 install.sh         |  2 +-
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/btrfs-snapshots.sh b/btrfs-snapshots.sh
index 14ffb5d..302be0d 100755
--- a/btrfs-snapshots.sh
+++ b/btrfs-snapshots.sh
@@ -17,6 +17,7 @@ TMP_MNT=${TMP_MNT:-/var/tmp/btrfs-backup}
 vols=()
 del=${DEL}
 dryrun=0
+fast=0
 periodity=${0%/*}
 periodity=${periodity##*/}
 if [[ $periodity =~ ^cron\... ]]; then
@@ -24,11 +25,12 @@ if [[ $periodity =~ ^cron\... ]]; then
 else
     periodity=
 fi
+
 case "$periodity" in
-    (.hourly) del=${HOURLY_DEL};;
+    (.hourly) del=${HOURLY_DEL}; fast=1;;
     (.daily) del=${DAILY_DEL};;
-    (.weekly) del=${WEEKLY_DEL};;
-    (.monthly) del=${MONTHLY_DEL};;
+    (.weekly) del=${WEEKLY_DEL}; fast=1;;
+    (.monthly) del=${MONTHLY_DEL}; fast=1;;
 esac
 while test $# -gt 0; do
     case "$1" in
@@ -39,6 +41,7 @@ OPTIONS
 
   -h, --help         show this help
   -n, --dry-run      execute dry run, do not backup, just show commands
+  -f, --fast         fast run, do not optimize btrfs (otherwise done daily)
   -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})
@@ -74,6 +77,7 @@ appended to the snapshot name, and the expiry is set meaningfull:
 EOF
                     exit;;
         (-n|--dry-run) dryrun=1;;
+        (-f|--fast) fast=1;;
         (-p|--path) shift; vols+=( "$1" );;
         (-m|--mnt) shift; TMP_MNT="$1";;
         (-d|--del) shift; del="$1";;
@@ -126,6 +130,10 @@ for fs in ${BTRFS_VOLUMES}; do
                 done
             fi
             echo " " umount "$TMP_MNT"
+            if test $fast -eq 0; then
+                echo " " btrfs filesystem defragment ${fs}
+                echo " " btrfs balance start ${fs}
+            fi
         else
             sudo btrfs subvolume snapshot "${TMP_MNT}${subvol}" "${TMP_MNT}${target}${date}"
             if test -n "$del"; then
@@ -135,6 +143,10 @@ for fs in ${BTRFS_VOLUMES}; do
             fi
         fi
         sudo umount "$TMP_MNT"
+        if test $fast -eq 0; then
+            sudo btrfs filesystem defragment ${fs}
+            sudo btrfs balance start ${fs}
+        fi
     else
         echo "ERROR: no device found for $fs" 1>&2
         exit 2
diff --git a/install.sh b/install.sh
index 62f9998..9781218 100755
--- a/install.sh
+++ b/install.sh
@@ -4,7 +4,7 @@ for f in hourly daily weekly monthly; do
     sudo cp btrfs-snapshots.sh /etc/cron.$f/btrfs-snapshots;
 done
 if ! test -e /etc/btrfs-snapshots.conf; then
-    cat > /etc/btrfs-snapshots.conf <<EOF
+    sudo tee /etc/btrfs-snapshots.conf > /dev/null <<EOF
 HOURLY_DEL=4
 DAILY_DEL=3
 WEEKLY_DEL=2