HDFS-7124. Remove EncryptionZoneManager.NULL_EZ. (clamb via wang)

(cherry picked from commit 7f0efe96f8)

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

@@ -265,6 +265,8 @@ Release 2.6.0 - UNRELEASED
 
     HDFS-7104. Fix and clarify INodeInPath getter functions. (Zhe Zhang via wang)
 
+    HDFS-7124. Remove EncryptionZoneManager.NULL_EZ. (clamb via wang)
+
   OPTIMIZATIONS
 
     HDFS-6690. Deduplicate xattr names in memory. (wang)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSClient.java

@@ -2940,8 +2940,7 @@ public class DFSClient implements java.io.Closeable, RemotePeerFactory,
           throws IOException {
     checkOpen();
     try {
-      final EncryptionZone ez = namenode.getEZForPath(src);
+      return namenode.getEZForPath(src);
-      return (ez.getId() < 0) ? null : ez;
     } catch (RemoteException re) {
       throw re.unwrapRemoteException(AccessControlException.class,
                                      UnresolvedPathException.class);

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

@@ -1340,7 +1340,9 @@ public class ClientNamenodeProtocolServerSideTranslatorPB implements
       GetEZForPathResponseProto.Builder builder =
           GetEZForPathResponseProto.newBuilder();
       final EncryptionZone ret = server.getEZForPath(req.getSrc());
+      if (ret != null) {
         builder.setZone(PBHelper.convert(ret));
+      }
       return builder.build();
     } catch (IOException e) {
       throw new ServiceException(e);

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

@@ -1347,7 +1347,11 @@ public class ClientNamenodeProtocolTranslatorPB implements
     try {
       final EncryptionZonesProtos.GetEZForPathResponseProto response =
           rpcProxy.getEZForPath(null, req);
+      if (response.hasZone()) {
         return PBHelper.convert(response.getZone());
+      } else {
+        return null;
+      }
     } catch (ServiceException e) {
       throw ProtobufHelper.getRemoteException(e);
     }

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

@@ -57,10 +57,6 @@ public class EncryptionZoneManager {
   public static Logger LOG = LoggerFactory.getLogger(EncryptionZoneManager
       .class);
 
-  public static final EncryptionZone NULL_EZ =
-      new EncryptionZone(-1, "", CipherSuite.UNKNOWN,
-          CryptoProtocolVersion.UNKNOWN, "");
-
   /**
    * EncryptionZoneInt is the internal representation of an encryption zone. The
    * external representation of an EZ is embodied in an EncryptionZone and
@@ -226,7 +222,7 @@ public class EncryptionZoneManager {
   EncryptionZone getEZINodeForPath(INodesInPath iip) {
     final EncryptionZoneInt ezi = getEncryptionZoneForPath(iip);
     if (ezi == null) {
-      return NULL_EZ;
+      return null;
     } else {
       return new EncryptionZone(ezi.getINodeId(), getFullPathName(ezi),
           ezi.getSuite(), ezi.getVersion(), ezi.getKeyName());

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

@@ -2846,8 +2846,7 @@ public class FSDirectory implements Closeable {
         iip = getINodesInPath(inode.getFullPathName(), true);
       }
       EncryptionZone encryptionZone = getEZForPath(iip);
-      if (encryptionZone == null ||
+      if (encryptionZone == null) {
-          encryptionZone.equals(EncryptionZoneManager.NULL_EZ)) {
         // not an encrypted file
         return null;
       } else if(encryptionZone.getPath() == null

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

@@ -63,5 +63,5 @@ message GetEZForPathRequestProto {
 }
 
 message GetEZForPathResponseProto {
-    required EncryptionZoneProto zone = 1;
+    optional EncryptionZoneProto zone = 1;
 }