fix out of bounds miscomputation

box.go

@@ -198,20 +198,20 @@ func TransferDirectZfs(from, to Addr) error {
 
 	}
 
-	fromFromSnapshotId := len(fromSnapshots)
+	fromFromSnapshotId := len(fromSnapshots) - 1
 	fromToSnapshotId := -1
 	for fromFromSnapshotId >= 0 {
-		fromFromSnapshotId = fromFromSnapshotId - 1
-		fromToSnapshotId = len(toSnapshots)
+		fromToSnapshotId = len(toSnapshots) - 1
 		for fromToSnapshotId >= 0 {
-			fromToSnapshotId = fromToSnapshotId - 1
 			if fromSnapshots[fromFromSnapshotId].name == toSnapshots[fromToSnapshotId].name {
 				break
 			}
+			fromToSnapshotId = fromToSnapshotId - 1
 		}
 		if fromToSnapshotId >= 0 {
 			break
 		}
+		fromFromSnapshotId = fromFromSnapshotId - 1
 	}
 
 	if fromFromSnapshotId == -1 {