diff --git a/box.go b/box.go
index 39c3d79..060e042 100644
--- a/box.go
+++ b/box.go
@@ -17,12 +17,42 @@ type Box struct {
 	zfs  *ZFSConfig
 }
 
+func (b *Box) ZFSTakeSnapshot(schedule, path string) (err error) {
+	err = b.SnapshotInitialize()
+	if err != nil {
+		return
+	}
+
+	b.zfs.M.Lock()
+	defer b.zfs.M.Unlock()
+
+	if *debugFlag {
+		log.Printf("Box.ZFSTakeSnapshot : %s : taking snapshot on %s for %s", b.Name, path, schedule)
+	}
+
+	timestamp := cfg.Now.Format("2006-01-02_15.04.05")
+	name := fmt.Sprintf("%s-%s--%s", schedule, timestamp, cfg.Zfsnap[schedule])
+	_, err = b.ssh.exec("zfs snapshot " + path + "@" + name)
+
+	if err != nil {
+		return
+	}
+
+	b.zfs.SnapshotAdded = true
+	b.zfs.SnapshotList = append(b.zfs.SnapshotList, Snapshot(path+"@"+name))
+
+	return
+}
+
 func (b *Box) ZFSGetLastSnapshot(path string) (last Snapshot, err error) {
 	err = b.SnapshotInitialize()
 	if err != nil {
 		return
 	}
 
+	b.zfs.M.Lock()
+	defer b.zfs.M.Unlock()
+
 	if *debugFlag {
 		log.Printf("Box.ZFSGetLastSnapshot : %s : Start %s (%d snapshots)", b.Name, path, len(b.zfs.SnapshotList))
 	}
@@ -44,6 +74,9 @@ func (b *Box) ZFSIsLastSnapshot(src Snapshot) (is bool, err error) {
 		return
 	}
 
+	b.zfs.M.Lock()
+	defer b.zfs.M.Unlock()
+
 	if *debugFlag {
 		log.Printf("SSHConfig.isLastSnapshot : %s : Start %s", b.Name, string(src))
 	}
@@ -66,6 +99,9 @@ func (b *Box) ZFSGetFirstSnapshot(path string) (first Snapshot, err error) {
 		return
 	}
 
+	b.zfs.M.Lock()
+	defer b.zfs.M.Unlock()
+
 	if *debugFlag {
 		log.Printf("SSHConfig.getFirstSnapshot : Start %s:%s", b.Name, path)
 	}
@@ -86,6 +122,9 @@ func (b *Box) ZFSGetNextSnapshot(src Snapshot) (next Snapshot, err error) {
 		return
 	}
 
+	b.zfs.M.Lock()
+	defer b.zfs.M.Unlock()
+
 	if *debugFlag {
 		log.Printf("Box.ZFSGetNextSnapshot : Start %s:%s", b.Name, string(src))
 	}
@@ -288,13 +327,3 @@ func (b *Box) SSHExec(cmd string) (buf *bytes.Buffer, err error) {
 	buf, err = b.ssh.exec(cmd)
 	return
 }
-
-func (b *Box) ZFSTakeSnapshot(schedule, path string) (err error) {
-	if *debugFlag {
-		log.Printf("Box.ZFSTakeSnapshot : %s : taking snapshot on %s for %s", b.Name, path, schedule)
-	}
-	timestamp := cfg.Now.Format("2006-01-02_15.04.05")
-	name := fmt.Sprintf("%s-%s--%s", schedule, timestamp, cfg.Zfsnap[schedule])
-	_, err = b.ssh.exec("zfs snapshot " + path + "@" + name)
-	return
-}
diff --git a/version.go b/version.go
index 6d26600..98a4c6c 100644
--- a/version.go
+++ b/version.go
@@ -1,6 +1,6 @@
 // Code generated by version.sh (@generated) DO NOT EDIT.
 package main
-var githash = "e192906"
-var buildstamp = "2021-11-14_09:20:16"
-var commits = "21"
-var version = "e192906-b21 - 2021-11-14_09:20:16"
+var githash = "0d3981e"
+var buildstamp = "2021-11-14_09:46:54"
+var commits = "22"
+var version = "0d3981e-b22 - 2021-11-14_09:46:54"