HDFS-11416. Refactor out system default erasure coding policy. Contributed by Andrew Wang.

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/StringUtils.java

@@ -177,6 +177,17 @@ public static String byteToHexString(byte bytes[]) {
     return byteToHexString(bytes, 0, bytes.length);
   }
 
+  /**
+   * Convert a byte to a hex string.
+   * @see #byteToHexString(byte[])
+   * @see #byteToHexString(byte[], int, int)
+   * @param b byte
+   * @return byte's hex value as a String
+   */
+  public static String byteToHexString(byte b) {
+    return byteToHexString(new byte[] {b});
+  }
+
   /**
    * Given a hexstring this will return the byte array corresponding to the
    * string

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

@@ -102,6 +102,7 @@ static List<XAttr> setErasureCodingPolicyXAttr(final FSNamesystem fsn,
     FSDirectory fsd = fsn.getFSDirectory();
     assert fsd.hasWriteLock();
     Preconditions.checkNotNull(srcIIP, "INodes cannot be null");
+    Preconditions.checkNotNull(ecPolicy, "EC policy cannot be null");
     String src = srcIIP.getPath();
     final INode inode = srcIIP.getLastINode();
     if (inode == null) {
@@ -112,11 +113,7 @@ static List<XAttr> setErasureCodingPolicyXAttr(final FSNamesystem fsn,
           "for a file " + src);
     }
 
-    // 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.
+    // Check that the EC policy is one of the active policies.
     boolean validPolicy = false;
     ErasureCodingPolicy[] activePolicies =
         FSDirErasureCodingOp.getErasureCodingPolicies(fsd.getFSNamesystem());
@@ -135,7 +132,6 @@ static List<XAttr> setErasureCodingPolicyXAttr(final FSNamesystem fsn,
           ecPolicy.getName() + " ] does not match any of the " +
           "supported policies. Please select any one of " + ecPolicyNames);
     }
-    }
 
     final XAttr ecXAttr;
     DataOutputStream dOut = null;

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

@@ -1108,8 +1108,7 @@ private void updateBlocks(FSDirectory fsDir, BlockListUpdatingOp op,
           // versions of Hadoop. Current versions always log
           // OP_ADD operations as each block is allocated.
           if (isStriped) {
-            newBI = new BlockInfoStriped(newBlock,
-                ErasureCodingPolicyManager.getSystemDefaultPolicy());
+            newBI = new BlockInfoStriped(newBlock, ecPolicy);
           } else {
             newBI = new BlockInfoContiguous(newBlock,
                 file.getFileReplication());

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

@@ -56,6 +56,7 @@
 
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
+import org.apache.hadoop.util.StringUtils;
 
 /** I-node for closed file. */
 @InterfaceAudience.Private
@@ -190,9 +191,10 @@ static long getBlockLayoutRedundancy(final BlockType blockType,
       if (blockType == STRIPED) {
         Preconditions.checkArgument(replication == null &&
             erasureCodingPolicyID != null);
-        Preconditions.checkArgument(
-            ErasureCodingPolicyManager.getPolicyByPolicyID(
-                erasureCodingPolicyID) != null);
+        Preconditions.checkArgument(ErasureCodingPolicyManager
+            .getPolicyByPolicyID(erasureCodingPolicyID) != null,
+            "Could not find EC policy with ID 0x" + StringUtils
+                .byteToHexString(erasureCodingPolicyID));
         layoutRedundancy |= BLOCK_TYPE_MASK_STRIPED;
         // Following bitwise OR with signed byte erasureCodingPolicyID is safe
         // as the PolicyID can never be in negative.
@@ -201,7 +203,8 @@ static long getBlockLayoutRedundancy(final BlockType blockType,
         Preconditions.checkArgument(replication != null &&
             erasureCodingPolicyID == null);
         Preconditions.checkArgument(replication >= 0 &&
-            replication <= MAX_REDUNDANCY);
+            replication <= MAX_REDUNDANCY,
+            "Invalid replication value " + replication);
         layoutRedundancy |= replication;
       }
       return layoutRedundancy;
@@ -513,9 +516,8 @@ public short getPreferredBlockReplication() {
     ErasureCodingPolicy ecPolicy =
         ErasureCodingPolicyManager.getPolicyByPolicyID(
             getErasureCodingPolicyID());
-    if (ecPolicy == null){
-      ecPolicy = ErasureCodingPolicyManager.getSystemDefaultPolicy();
-    }
+    Preconditions.checkNotNull(ecPolicy, "Could not find EC policy with ID 0x"
+        + StringUtils.byteToHexString(getErasureCodingPolicyID()));
     return (short) (ecPolicy.getNumDataUnits() + ecPolicy.getNumParityUnits());
   }
 

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

@@ -1311,11 +1311,8 @@ public String toString() {
 
   @VisibleForTesting
   static class ErasureCodingResult extends Result {
-    final String defaultECPolicy;
 
     ErasureCodingResult(Configuration conf) {
-      defaultECPolicy = ErasureCodingPolicyManager.getSystemDefaultPolicy()
-          .getName();
     }
 
     @Override
@@ -1392,8 +1389,7 @@ public String toString() {
             ((float) (numMisReplicatedBlocks * 100) / (float) totalBlocks))
             .append(" %)");
       }
-      res.append("\n Default ecPolicy:\t\t").append(defaultECPolicy)
-          .append("\n Average block group size:\t").append(
+      res.append("\n Average block group size:\t").append(
           getReplicationFactor()).append("\n Missing block groups:\t\t").append(
           missingIds.size()).append("\n Corrupt block groups:\t\t").append(
           corruptBlocks).append("\n Missing internal blocks:\t").append(

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestStripedINodeFile.java

@@ -54,6 +54,7 @@
 import org.junit.Assert;
 import org.junit.Rule;
 import org.junit.Test;
+import org.junit.rules.ExpectedException;
 import org.junit.rules.Timeout;
 
 /**
@@ -83,6 +84,18 @@ private static INodeFile createStripedINodeFile() {
         HdfsConstants.COLD_STORAGE_POLICY_ID, BlockType.STRIPED);
   }
 
+  @Rule
+  public ExpectedException thrown = ExpectedException.none();
+
+  @Test
+  public void testInvalidECPolicy() throws IllegalArgumentException {
+    thrown.expect(IllegalArgumentException.class);
+    thrown.expectMessage("Could not find EC policy with ID 0xbb");
+    new INodeFile(HdfsConstants.GRANDFATHER_INODE_ID, null, perm, 0L, 0L,
+        null, null, (byte) 0xBB, 1024L,
+        HdfsConstants.COLD_STORAGE_POLICY_ID, BlockType.STRIPED);
+  }
+
   @Test
   public void testBlockStripedFeature()
       throws IOException, InterruptedException{