diff --git src/java/org/apache/hadoop/hdfs/server/datanode/FSDataset.java src/java/org/apache/hadoop/hdfs/server/datanode/FSDataset.java
index e6f1f1c..98011e7 100644
--- src/java/org/apache/hadoop/hdfs/server/datanode/FSDataset.java
+++ src/java/org/apache/hadoop/hdfs/server/datanode/FSDataset.java
@@ -332,7 +332,7 @@ public class FSDataset implements FSConstants, FSDatasetInterface {
           throw new IOException("Mkdirs failed to create " + tmpDir.toString());
         }
       }
-      this.usage = new DF(parent, conf);
+      this.usage = DF.getDF(parent, conf);
       this.dfsUsage = new DU(parent, conf);
       this.dfsUsage.start();
     }
diff --git src/test/hdfs/org/apache/hadoop/hdfs/server/namenode/TestNamenodeCapacityReport.java src/test/hdfs/org/apache/hadoop/hdfs/server/namenode/TestNamenodeCapacityReport.java
index 827e3f1..7798920 100644
--- src/test/hdfs/org/apache/hadoop/hdfs/server/namenode/TestNamenodeCapacityReport.java
+++ src/test/hdfs/org/apache/hadoop/hdfs/server/namenode/TestNamenodeCapacityReport.java
@@ -86,7 +86,7 @@ public class TestNamenodeCapacityReport extends TestCase {
         assertTrue(percentRemaining == ((100.0f * (float)remaining)/(float)configCapacity));
       }   
       
-      DF df = new DF(new File(cluster.getDataDirectory()), conf);
+      DF df = DF.getDF(new File(cluster.getDataDirectory()), conf);
      
       //
       // Currently two data directories are created by the data node