HDFS-8853. Erasure Coding: Provide ECSchema validation when setting EC policy. Contributed by J.Andreina.

Change-Id: I9211d9728480225a407d82e6c0bea1a928adfa11

hadoop-hdfs-project/hadoop-hdfs/CHANGES-HDFS-EC-7285.txt

@@ -415,3 +415,6 @@
 
     HDFS-8833. Erasure coding: store EC schema and cell size in INodeFile and 
     eliminate notion of EC zones. (zhz)
+
+    HDFS-8853. Erasure Coding: Provide ECSchema validation when setting EC
+    policy. (andreina via zhz)

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

@@ -28,6 +28,8 @@
 
 import com.google.common.base.Preconditions;
 import com.google.common.collect.Lists;
+
+import org.apache.hadoop.HadoopIllegalArgumentException;
 import org.apache.hadoop.fs.XAttr;
 import org.apache.hadoop.fs.XAttrSetFlag;
 import org.apache.hadoop.fs.permission.FsAction;
@@ -105,6 +107,26 @@ static List<XAttr> createErasureCodingPolicyXAttr(final FSNamesystem fsn,
     // System default erasure coding policy will be used since no specified.
     if (ecPolicy == null) {
       ecPolicy = ErasureCodingPolicyManager.getSystemDefaultPolicy();
+    } else {
+      // If ecPolicy is specified check if it is one among active policies.
+      boolean validPolicy = false;
+      ErasureCodingPolicy[] activePolicies =
+          FSDirErasureCodingOp.getErasureCodingPolicies(fsd.getFSNamesystem());
+      for (ErasureCodingPolicy activePolicy : activePolicies) {
+        if (activePolicy.equals(ecPolicy)) {
+          validPolicy = true;
+          break;
+        }
+      }
+      if (!validPolicy) {
+        List<String> ecPolicyNames = new ArrayList<String>();
+        for (ErasureCodingPolicy activePolicy : activePolicies) {
+          ecPolicyNames.add(activePolicy.getName());
+        }
+        throw new HadoopIllegalArgumentException("Policy [ " +
+            ecPolicy.getName()+ " ] does not match any of the " +
+            "supported policies. Please select any one of " + ecPolicyNames);
+      }
     }
 
     final XAttr ecXAttr;

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

@@ -26,6 +26,7 @@
 import org.apache.hadoop.hdfs.server.namenode.FSNamesystem;
 import org.apache.hadoop.hdfs.server.namenode.INode;
 import org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy;
+import org.apache.hadoop.io.erasurecode.ECSchema;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
@@ -208,4 +209,26 @@ private void verifyErasureCodingInfo(
     assertEquals("Actually used ecPolicy should be equal with target ecPolicy",
         usingECPolicy, ecPolicy);
   }
+
+  @Test
+  public void testCreationErasureCodingZoneWithInvalidPolicy()
+      throws IOException {
+    ECSchema rsSchema = new ECSchema("rs", 4, 2);
+    String policyName = "RS-4-2-128k";
+    int cellSize = 128 * 1024;
+    ErasureCodingPolicy ecPolicy=
+        new ErasureCodingPolicy(policyName,rsSchema,cellSize);
+    String src = "/ecZone4-2";
+    final Path ecDir = new Path(src);
+    try {
+      fs.mkdir(ecDir, FsPermission.getDirDefault());
+      fs.getClient().setErasureCodingPolicy(src, ecPolicy);
+      fail("HadoopIllegalArgumentException should be thrown for"
+          + "setting an invalid erasure coding policy");
+    } catch (Exception e) {
+      assertExceptionContains("Policy [ RS-4-2-128k ] does not match " +
+          "any of the supported policies",e);
+    }
+  }
+
 }