fix zfs send for expired snapshots

box.go

@@ -198,13 +198,18 @@ func TransferDirectZfs(from, to Addr) error {
 
 	}
 
-	fromFromSnapshotId := -1
-	lastToSnapshot := toSnapshots[len(toSnapshots)-1]
-	log.WithFields(log.Fields{"from": from, "to": to}).Debugf("searching last snapshot %s", lastToSnapshot.String())
-	for id, v := range fromSnapshots {
-		if v.name == lastToSnapshot.name {
-			fromFromSnapshotId = id
-			log.WithFields(log.Fields{"from": from, "to": to}).Debugf("found %s", v.String())
+	fromFromSnapshotId := len(fromSnapshots)
+	fromToSnapshotId := -1
+	for fromFromSnapshotId >= 0 {
+		fromFromSnapshotId = fromFromSnapshotId - 1
+		fromToSnapshotId = len(toSnapshots)
+		for fromToSnapshotId >= 0 {
+			fromToSnapshotId = fromToSnapshotId - 1
+			if fromSnapshots[fromFromSnapshotId].name == toSnapshots[fromToSnapshotId].name {
+				break
+			}
+		}
+		if fromToSnapshotId >= 0 {
 			break
 		}
 	}