diff --git a/core/src/main/java/hudson/org/apache/tools/tar/TarOutputStream.java b/core/src/main/java/hudson/org/apache/tools/tar/TarOutputStream.java
index e60a927e550928e87fd38345e26600c130a7ffd6..f23e44262847de611c21231223966e8f78d1c5b7 100644
--- a/core/src/main/java/hudson/org/apache/tools/tar/TarOutputStream.java
+++ b/core/src/main/java/hudson/org/apache/tools/tar/TarOutputStream.java
@@ -315,7 +315,7 @@ public class TarOutputStream extends FilterOutputStream {
 
                 wOffset += numToWrite;
                 this.assemLen += numToWrite;
-                numToWrite -= numToWrite;
+                numToWrite = 0;
             }
         }