From b2069ce598d72ffc367a7296b436027e78926018 Mon Sep 17 00:00:00 2001
From: Alice Gaudon <alice@gaudon.pro>
Date: Thu, 4 Mar 2021 14:21:35 +0100
Subject: [PATCH] Separate snapshot creation from snapshot sync

---
 zfs_backup_dataset.sh |   2 +-
 zsc-sync.sh           | 130 ++++++++++++++++++++++++++++++++++++++++++
 zsc.sh                |  40 ++++++++-----
 3 files changed, 158 insertions(+), 14 deletions(-)
 create mode 100755 zsc-sync.sh

diff --git a/zfs_backup_dataset.sh b/zfs_backup_dataset.sh
index aee921d..6b3a27c 100755
--- a/zfs_backup_dataset.sh
+++ b/zfs_backup_dataset.sh
@@ -53,7 +53,7 @@ for local_snapshot in "${LOCAL_SNAPSHOTS[@]}"; do
 	done
 
 	if [ $found = true ] ; then
-		echo "> Found remotely, settings as last snapshot"
+		echo "> Found remotely, setting as last snapshot"
 		LAST_SNAPSHOT=$local_snapshot
 		EXISTING_SNAPSHOT=""
 	else
diff --git a/zsc-sync.sh b/zsc-sync.sh
new file mode 100755
index 0000000..fa1e245
--- /dev/null
+++ b/zsc-sync.sh
@@ -0,0 +1,130 @@
+#!/bin/bash
+
+# ZSC-Sync - zfs snapshot cron sync
+# Usage: <script> <remote> <remote_dataset>
+
+ZSC_CONFIG="$HOME/.zsc"
+
+REMOTE=$1
+if test -z "$REMOTE"; then
+	echo "No remote specified"
+	exit -1
+fi
+
+REMOTE_ROOT_DATASET=$2
+if test -z "$REMOTE_ROOT_DATASET"; then
+	echo "No remote root dataset specified"
+	exit -1
+fi
+
+
+### LOCK ###
+echo "Locking ZSC"
+if ! lockfile-create -p -r 2 "zsc"; then
+	echo "Another backup is running, aborting"
+	exit 49
+fi
+
+
+handle_dataset() {
+	DATASET=$1
+	D=$2
+	W=$3
+	M=$4
+	Y=$5
+
+	PREFIX=$6
+	if test -z "$PREFIX"; then
+		PREFIX="zsc-"
+	fi
+
+	if test "!no_prefix!" = "$PREFIX"; then
+		PREFIX=""
+	fi
+
+	RECURSIVE=$7
+	if [ $recusive = 'true' ]; then
+		echo "Recursive"
+	fi
+
+	TARGET_REMOTE_DATASET="$REMOTE_ROOT_DATASET/"$(echo -e $DATASET | sed -r "s/\//_/g")
+
+	echo "--- $DATASET -> $TARGET_REMOTE_DATASET ---"
+
+
+	### Resume existing transfer ###
+	RESUME_TOKEN=$(ssh $REMOTE zfs get -H -p receive_resume_token -o value "$TARGET_REMOTE_DATASET")
+	if [ "$RESUME_TOKEN" != "" ] && [ "$RESUME_TOKEN" != "-" ]; then
+		echo "Resuming interrupted transfer..."
+		zfs send -v -t "$RESUME_TOKEN" | ssh $REMOTE zfs receive -F -s "$TARGET_REMOTE_DATASET" || return 1
+		echo "Resumed transfer finished."
+		return 0
+	fi
+
+
+	### Sync existing snapshots ###
+	REMOTE_SNAPSHOTS=($(ssh $REMOTE zfs list -H -t snapshot -o name -s creation $TARGET_REMOTE_DATASET | cut -d"@" -f 2))
+	LOCAL_SNAPSHOTS=($(zfs list -H -t snapshot -o name -s creation $DATASET | cut -d"@" -f 2))
+
+	echo "Remote snapshots: ${#REMOTE_SNAPSHOTS[@]}"
+	echo "Local snapshots: ${#LOCAL_SNAPSHOTS[@]}"
+
+	for local_snapshot in "${LOCAL_SNAPSHOTS[@]}"; do
+		echo "Syncing local snapshot $local_snapshot ..."
+		found=false
+		for remote_snapshot in "${REMOTE_SNAPSHOTS[@]}"; do
+			if [ "$remote_snapshot" = "$local_snapshot" ] ; then
+				found=true
+				break
+			fi
+		done
+
+		if [ $found = true ] ; then
+			echo "> Found remotely, setting as last snapshot"
+			FROM_SNAPSHOT=$local_snapshot
+			TO_SNAPSHOT=""
+		else
+			echo "> Needs sync"
+			TO_SNAPSHOT=$local_snapshot
+		fi
+	done
+
+	echo "Snapshot are synchronized up to $FROM_SNAPSHOT"
+
+	if test ! -z "$TO_SNAPSHOT"; then
+		echo "Synchronizing snapshots from $FROM_SNAPSHOT to $TO_SNAPSHOT ..."
+
+		if test ! -z "$FROM_SNAPSHOT"; then
+			incr="-I $FROM_SNAPSHOT"
+		fi
+		if [ $recusive = 'true' ]; then
+			recu="-R"
+		fi
+		zfs send -v -p $recu $incr $TO_SNAPSHOT | ssh $REMOTE zfs receive -F -s $TARGET_REMOTE_DATASET || return 1
+
+		echo "Done"
+	fi
+}
+
+cat "$ZSC_CONFIG" | while IFS=: read dataset recursive d w m y prefix; do
+	echo "| ##### Dataset: $dataset Recursive: $recursive Prefix: $prefix d: $d w: $w m: $m y: $y #####"
+
+	if [ $recursive = "true" ]; then
+		SUBDATASETS=($(zfs list -o name | grep "$dataset/"))
+		echo -e "| Subdatasets: ${SUBDATASETS[@]}"
+		echo -e '|'
+		#for p in "${SUBDATASETS[@]}"; do
+		#	handle_dataset $p $d $w $m $y $prefix | awk '{print "| " $0}' || exit 1
+		#	echo -e '|'
+		#done
+	fi
+
+	handle_dataset $dataset $d $w $m $y $prefix $recursive | awk '{print "| " $0}' || exit 1
+
+	echo -e "----------------------------------------------------------------------"
+done
+
+
+### UNLOCK ###
+echo "Unlocking ZSC"
+lockfile-remove "zsc"
diff --git a/zsc.sh b/zsc.sh
index 48668bd..2eece61 100755
--- a/zsc.sh
+++ b/zsc.sh
@@ -7,12 +7,21 @@ CONFIG_FILE="$HOME/.zsc"
 FORMAT='+%Y-%m-%d'
 DATE=$(date $FORMAT)
 
+
+### LOCK ###
+echo "Locking ZSC"
+if ! lockfile-create -p -r 2 "zsc"; then
+	echo "Another backup is running, aborting"
+	exit 49
+fi
+
+
 split_date() {
 	echo "$1" | sed -E 's/([0-9]{4})-([0-9]{2})-([0-9]{2})/\1\n\2\n\3/'
 }
 
-handle_pool() {
-	POOL=$1
+handle_dataset() {
+	DATASET=$1
 	D=$2
 	W=$3
 	M=$4
@@ -27,9 +36,9 @@ handle_pool() {
 		PREFIX=""
 	fi
 
-	echo "--- $POOL --- $D $W $M $Y $PREFIX"
+	echo "--- $DATASET --- $D $W $M $Y $PREFIX"
 
-	SNAPSHOTS=($(zfs list -t snapshot -o name | grep "$POOL@$PREFIX" | sort -r))
+	SNAPSHOTS=($(zfs list -t snapshot -o name | grep "$DATASET@$PREFIX" | sort -r))
 	echo "Snapshots: ${#SNAPSHOTS[@]}"
 
 	EXISTS=0
@@ -66,25 +75,30 @@ handle_pool() {
 	done
 
 	if [ $EXISTS -eq 0 ]; then
-		echo -e "Creating snapshot $POOL@$PREFIX$DATE"
-		zfs snapshot $POOL@$PREFIX$DATE
+		echo -e "Creating snapshot $DATASET@$PREFIX$DATE"
+		zfs snapshot $DATASET@$PREFIX$DATE
 	fi
 }
 
-cat "$CONFIG_FILE" | while IFS=: read pool recursive d w m y prefix; do
-	echo "| ##### Pool: $pool Recursive: $recursive Prefix: $prefix d: $d w: $w m: $m y: $y #####"
+cat "$CONFIG_FILE" | while IFS=: read dataset recursive d w m y prefix; do
+	echo "| ##### Dataset: $dataset Recursive: $recursive Prefix: $prefix d: $d w: $w m: $m y: $y #####"
 
 	if [ $recursive = "true" ]; then
-		SUBPOOLS=($(zfs list -o name | grep "$pool/"))
-		echo -e "Subpools: ${SUBPOOLS[@]}"
+		SUBDATASETS=($(zfs list -o name | grep "$dataset/"))
+		echo -e "| Subdatasets: ${SUBDATASETS[@]}"
 		echo -e '|'
-		for p in "${SUBPOOLS[@]}"; do
-			handle_pool $p $d $w $m $y $prefix | awk '{print "| " $0}'
+		for p in "${SUBDATASETS[@]}"; do
+			handle_dataset $p $d $w $m $y $prefix | awk '{print "| " $0}'
 			echo -e '|'
 		done
 	fi
 
-	handle_pool $pool $d $w $m $y $prefix | awk '{print "| " $0}'
+	handle_dataset $dataset $d $w $m $y $prefix | awk '{print "| " $0}'
 
 	echo -e "----------------------------------------------------------------------"
 done
+
+
+### UNLOCK ###
+echo "Unlocking ZSC"
+lockfile-remove "zsc"