HDFS-13806. EC: No error message for unsetting EC policy of the directory inherits the erasure coding policy from an ancestor directory. Contributed by Ayush Saxena.

(cherry picked from commit 30eceec3420fc6be00d3878ba787bd9518d3ca0e)

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

@@ -133,6 +133,7 @@
 import org.apache.hadoop.hdfs.protocol.LocatedBlock;
 import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
 import org.apache.hadoop.hdfs.protocol.NSQuotaExceededException;
+import org.apache.hadoop.hdfs.protocol.NoECPolicySetException;
 import org.apache.hadoop.hdfs.protocol.OpenFileEntry;
 import org.apache.hadoop.hdfs.protocol.OpenFilesIterator;
 import org.apache.hadoop.hdfs.protocol.OpenFilesIterator.OpenFilesType;
@@ -2757,7 +2758,7 @@ public void unsetErasureCodingPolicy(String src) throws IOException {
       throw re.unwrapRemoteException(AccessControlException.class,
           SafeModeException.class,
           UnresolvedPathException.class,
-          FileNotFoundException.class);
+          FileNotFoundException.class, NoECPolicySetException.class);
     }
   }
 

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/protocol/NoECPolicySetException.java

@@ -0,0 +1,37 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.hadoop.hdfs.protocol;
+
+import java.io.IOException;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+
+/**
+ *Thrown when no EC policy is set explicitly on the directory.
+ */
+@InterfaceAudience.Private
+@InterfaceStability.Evolving
+public class NoECPolicySetException extends IOException {
+  private static final long serialVersionUID = 1L;
+
+  public NoECPolicySetException(String msg) {
+    super(msg);
+  }
+}

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

@@ -28,6 +28,7 @@
 import org.apache.hadoop.hdfs.XAttrHelper;
 import org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy;
 import org.apache.hadoop.hdfs.protocol.ErasureCodingPolicyInfo;
+import org.apache.hadoop.hdfs.protocol.NoECPolicySetException;
 import org.apache.hadoop.hdfs.server.namenode.FSDirectory.DirOp;
 import org.apache.hadoop.io.IOUtils;
 import org.apache.hadoop.io.WritableUtils;
@@ -206,6 +207,9 @@ static FileStatus unsetErasureCodingPolicy(final FSNamesystem fsn,
     }
     if (xAttrs != null) {
       fsn.getEditLog().logRemoveXAttrs(src, xAttrs, logRetryCache);
+    } else {
+      throw new NoECPolicySetException(
+          "No erasure coding policy explicitly set on " + src);
     }
     return fsd.getAuditFileInfo(iip);
   }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/ECAdmin.java

@@ -26,6 +26,7 @@
 import org.apache.hadoop.hdfs.protocol.AddErasureCodingPolicyResponse;
 import org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy;
 import org.apache.hadoop.hdfs.protocol.ErasureCodingPolicyInfo;
+import org.apache.hadoop.hdfs.protocol.NoECPolicySetException;
 import org.apache.hadoop.hdfs.util.ECPolicyLoader;
 import org.apache.hadoop.io.erasurecode.ErasureCodeConstants;
 import org.apache.hadoop.tools.TableListing;
@@ -424,6 +425,12 @@ public int run(Configuration conf, List<String> args) throws IOException {
               "non-empty directory will not automatically convert existing" +
               " files to replicated data.");
         }
+      } catch (NoECPolicySetException e) {
+        System.err.println(AdminHelper.prettifyException(e));
+        System.err.println("Use '-setPolicy -path <PATH> -replicate' to enforce"
+            + " default replication policy irrespective of EC policy"
+            + " defined on parent.");
+        return 2;
       } catch (Exception e) {
         System.err.println(AdminHelper.prettifyException(e));
         return 2;

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestUnsetAndChangeDirectoryEcPolicy.java

@@ -23,6 +23,7 @@
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.hdfs.protocol.SystemErasureCodingPolicies;
 import org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy;
+import org.apache.hadoop.hdfs.protocol.NoECPolicySetException;
 import org.apache.hadoop.io.erasurecode.CodecUtil;
 import org.apache.hadoop.io.erasurecode.ErasureCodeNative;
 import org.apache.hadoop.io.erasurecode.rawcoder.NativeRSRawErasureCoderFactory;
@@ -98,7 +99,11 @@ public void testUnsetEcPolicy() throws Exception {
 
     fs.mkdirs(dirPath);
     // Test unset a directory which has no EC policy
-    fs.unsetErasureCodingPolicy(dirPath);
+    try {
+      fs.unsetErasureCodingPolicy(dirPath);
+      fail();
+    } catch (NoECPolicySetException e) {
+    }
     // Set EC policy on directory
     fs.setErasureCodingPolicy(dirPath, ecPolicy.getName());
 
@@ -126,8 +131,8 @@ public void testUnsetEcPolicy() throws Exception {
   }
 
   /*
-  * Test nested directory with different EC policy.
+   * Test nested directory with different EC policy.
-  */
+   */
   @Test
   public void testNestedEcPolicy() throws Exception {
     final int numBlocks = 1;
@@ -199,7 +204,11 @@ public void testUnsetRootDirEcPolicy() throws Exception {
     final Path replicateFilePath = new Path(rootPath, "rep_file");
 
     // Test unset root path which has no EC policy
-    fs.unsetErasureCodingPolicy(rootPath);
+    try {
+      fs.unsetErasureCodingPolicy(rootPath);
+      fail();
+    } catch (NoECPolicySetException e) {
+    }
     // Set EC policy on root path
     fs.setErasureCodingPolicy(rootPath, ecPolicy.getName());
     DFSTestUtil.createFile(fs, ecFilePath, fileLen, (short) 1, 0L);
@@ -238,7 +247,11 @@ public void testChangeRootDirEcPolicy() throws Exception {
     final ErasureCodingPolicy ec32Policy = SystemErasureCodingPolicies
         .getByID(SystemErasureCodingPolicies.RS_3_2_POLICY_ID);
 
-    fs.unsetErasureCodingPolicy(rootPath);
+    try {
+      fs.unsetErasureCodingPolicy(rootPath);
+      fail();
+    } catch (NoECPolicySetException e) {
+    }
     fs.setErasureCodingPolicy(rootPath, ecPolicy.getName());
     // Create RS(6,3) EC policy file
     DFSTestUtil.createFile(fs, ec63FilePath, fileLen, (short) 1, 0L);

hadoop-hdfs-project/hadoop-hdfs/src/test/resources/testErasureCodingConf.xml

@@ -359,6 +359,30 @@
       </comparators>
     </test>
 
+    <test>
+      <description>unsetPolicy : unset on non EC directory</description>
+      <test-commands>
+        <command>-fs NAMENODE -mkdir /ecdir</command>
+        <command>-fs NAMENODE -mkdir /ecdir/child</command>
+        <ec-admin-command>-fs NAMENODE -unsetPolicy -path /ecdir/child</ec-admin-command>
+      </test-commands>
+      <cleanup-commands>
+        <command>-fs NAMENODE -rm /ecdir/child/ecfile</command>
+        <command>-fs NAMENODE -rmdir /ecdir/child</command>
+        <command>-fs NAMENODE -rmdir /ecdir</command>
+      </cleanup-commands>
+      <comparators>
+        <comparator>
+          <type>SubstringComparator</type>
+          <expected-output>NoECPolicySetException: No erasure coding policy explicitly set on /ecdir/child</expected-output>
+        </comparator>
+        <comparator>
+          <type>SubstringComparator</type>
+          <expected-output>Use '-setPolicy -path &lt;PATH&gt; -replicate' to enforce default replication policy irrespective of EC policy defined on parent.</expected-output>
+        </comparator>
+      </comparators>
+    </test>
+
     <test>
       <description>unsetPolicy : unset policy on non-empty directory</description>
       <test-commands>