HDFS-6373. Remove support for extended attributes on symlinks. Contributed by Charles Lamb.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-2006@1594438 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES-HDFS-2006.txt

@@ -31,6 +31,8 @@ HDFS-2006 (Unreleased)
 
     HDFS-6377. Unify xattr name and value limits into a single limit. (wang)
 
+    HDFS-6373. Remove support for extended attributes on symlinks (Charles Lamb via wang)
+
   OPTIMIZATIONS
 
     HDFS-6346. Optimize OP_SET_XATTRS by persisting single Xattr entry per setXattr/removeXattr api call

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INodeSymlink.java

@@ -25,6 +25,7 @@ import org.apache.hadoop.fs.permission.PermissionStatus;
 import org.apache.hadoop.hdfs.DFSUtil;
 import org.apache.hadoop.hdfs.protocol.QuotaExceededException;
 import org.apache.hadoop.hdfs.server.namenode.snapshot.Snapshot;
+import org.apache.hadoop.hdfs.server.namenode.XAttrFeature;
 
 /**
  * An {@link INode} representing a symbolic link.
@@ -110,4 +111,19 @@ public class INodeSymlink extends INodeWithAdditionalFields {
     super.dumpTreeRecursively(out, prefix, snapshot);
     out.println();
   }
+
+  @Override
+  final XAttrFeature getXAttrFeature(int snapshotId) {
+    throw new UnsupportedOperationException("XAttrs are not supported on symlinks");
+  }
+  
+  @Override
+  public void removeXAttrFeature() {
+    throw new UnsupportedOperationException("XAttrs are not supported on symlinks");
+  }
+  
+  @Override
+  public void addXAttrFeature(XAttrFeature f) {
+    throw new UnsupportedOperationException("XAttrs are not supported on symlinks");
+  }
 }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/INodeWithAdditionalFields.java

@@ -343,7 +343,7 @@ public abstract class INodeWithAdditionalFields extends INode
   }
   
   @Override
-  final XAttrFeature getXAttrFeature(int snapshotId) {
+  XAttrFeature getXAttrFeature(int snapshotId) {
     if (snapshotId != Snapshot.CURRENT_STATE_ID) {
       return getSnapshotINode(snapshotId).getXAttrFeature();
     }