svn merge -c 1373193 from trunk for HDFS-3794. WebHDFS OPEN returns the incorrect Content-Length in the HTTP header when offset is specified and length is omitted.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1373195 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -447,6 +447,10 @@ Release 2.0.1-alpha - UNRELEASED
 
     HDFS-3658. Fix bugs in TestDFSClientRetries and add more tests.  (szetszwo)
 
+    HDFS-3794. WebHDFS OPEN returns the incorrect Content-Length in the HTTP
+    header when offset is specified and length is omitted.
+    (Ravi Prakash via szetszwo)
+
   BREAKDOWN OF HDFS-3042 SUBTASKS
 
     HDFS-2185. HDFS portion of ZK-based FailoverController (todd)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/web/resources/DatanodeWebHdfsMethods.java

@@ -411,7 +411,7 @@ public class DatanodeWebHdfsMethods {
       }
       
       final long n = length.getValue() != null? length.getValue()
-          : in.getVisibleLength();
+        : in.getVisibleLength() - offset.getValue();
       return Response.ok(new OpenEntity(in, n, dfsclient)).type(
           MediaType.APPLICATION_OCTET_STREAM).build();
     }