HDFS-5043. Merging r1508729 from branch-2

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.1-beta@1509463 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -17,6 +17,9 @@ Release 2.1.1-beta - UNRELEASED
 
   BUG FIXES
 
+    HDFS-5043. For HdfsFileStatus, set default value of childrenNum to -1
+    instead of 0 to avoid confusing applications. (brandonli)
+
 Release 2.1.0-beta - 2013-08-06
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocolPB/PBHelper.java

@@ -1056,7 +1056,7 @@ public class PBHelper {
         fs.getPath().toByteArray(),
         fs.hasFileId()? fs.getFileId(): INodeId.GRANDFATHER_INODE_ID,
         fs.hasLocations() ? PBHelper.convert(fs.getLocations()) : null,
-        fs.hasChildrenNum() ? fs.getChildrenNum() : 0);
+        fs.hasChildrenNum() ? fs.getChildrenNum() : -1);
   }
 
   public static SnapshottableDirectoryStatus convert(

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/web/JsonUtil.java

@@ -249,7 +249,7 @@ public class JsonUtil {
     final long fileId = m.containsKey("fileId") ? (Long) m.get("fileId")
         : INodeId.GRANDFATHER_INODE_ID;
     Long childrenNumLong = (Long) m.get("childrenNum");
-    final int childrenNum = (childrenNumLong == null) ? 0
+    final int childrenNum = (childrenNumLong == null) ? -1
             : childrenNumLong.intValue();
     return new HdfsFileStatus(len, type == PathType.DIRECTORY, replication,
         blockSize, mTime, aTime, permission, owner, group,

hadoop-hdfs-project/hadoop-hdfs/src/main/proto/hdfs.proto

@@ -179,7 +179,7 @@ message HdfsFileStatusProto {
 
   // Optional field for fileId
   optional uint64 fileId = 13 [default = 0]; // default as an invalid id
-  optional uint32 childrenNum = 14 [default = 0];
+  optional int32 childrenNum = 14 [default = -1];
 } 
 
 /**