HDFS-2810. Leases not getting renewed properly by clients. Contributed by Todd Lipcon.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1233793 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -159,6 +159,8 @@ Release 0.23.1 - UNRELEASED
     HDFS-2790. FSNamesystem.setTimes throws exception with wrong
     configuration name in the message. (Arpit Gupta via eli)
 
+    HDFS-2810. Leases not getting renewed properly by clients (todd)
+
 Release 0.23.0 - 2011-11-01 
 
   INCOMPATIBLE CHANGES

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

@@ -374,11 +374,17 @@ boolean isClientRunning() {
     return clientRunning;
   }
 
-  /** Renew leases */
-  void renewLease() throws IOException {
+  /**
+   * Renew leases.
+   * @return true if lease was renewed. May return false if this
+   * client has been closed or has no files open.
+   **/
+  boolean renewLease() throws IOException {
     if (clientRunning && !isFilesBeingWrittenEmpty()) {
       namenode.renewLease(clientName);
+      return true;
     }
+    return false;
   }
 
   /** Abort and release resources held.  Ignore all errors. */

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

@@ -67,7 +67,7 @@
  * </p>
  */
 class LeaseRenewer {
-  private static final Log LOG = LogFactory.getLog(LeaseRenewer.class);
+  static final Log LOG = LogFactory.getLog(LeaseRenewer.class);
 
   static final long LEASE_RENEWER_GRACE_DEFAULT = 60*1000L;
   static final long LEASE_RENEWER_SLEEP_DEFAULT = 1000L;
@@ -407,7 +407,13 @@ public int compare(final DFSClient left, final DFSClient right) {
       final DFSClient c = copies.get(i);
       //skip if current client name is the same as the previous name.
       if (!c.getClientName().equals(previousName)) {
-        c.renewLease();
+        if (!c.renewLease()) {
+          if (LOG.isDebugEnabled()) {
+            LOG.debug("Did not renew lease for client " +
+                c);
+          }
+          continue;
+        }
         previousName = c.getClientName();
         if (LOG.isDebugEnabled()) {
           LOG.debug("Lease renewed for client " + previousName);

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

@@ -17,11 +17,14 @@
  */
 package org.apache.hadoop.hdfs;
 
+import static org.junit.Assert.*;
+
 import java.io.IOException;
 import java.util.concurrent.atomic.AtomicInteger;
 
 
 import org.apache.hadoop.security.UserGroupInformation;
+import org.apache.hadoop.test.GenericTestUtils;
 import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;
@@ -29,6 +32,8 @@
 import org.mockito.invocation.InvocationOnMock;
 import org.mockito.stubbing.Answer;
 
+import com.google.common.base.Supplier;
+
 public class TestLeaseRenewer {
   private String FAKE_AUTHORITY="hdfs://nn1/";
   private UserGroupInformation FAKE_UGI_A =
@@ -46,19 +51,24 @@ public class TestLeaseRenewer {
   
   @Before
   public void setupMocksAndRenewer() throws IOException {
-    MOCK_DFSCLIENT = Mockito.mock(DFSClient.class);
-    Mockito.doReturn(true)
-      .when(MOCK_DFSCLIENT).isClientRunning();
-    Mockito.doReturn((int)FAST_GRACE_PERIOD)
-      .when(MOCK_DFSCLIENT).getHdfsTimeout();
-    Mockito.doReturn("myclient")
-      .when(MOCK_DFSCLIENT).getClientName();
+    MOCK_DFSCLIENT = createMockClient();
     
     renewer = LeaseRenewer.getInstance(
         FAKE_AUTHORITY, FAKE_UGI_A, MOCK_DFSCLIENT);
     renewer.setGraceSleepPeriod(FAST_GRACE_PERIOD);
 }
  
+  private DFSClient createMockClient() {
+    DFSClient mock = Mockito.mock(DFSClient.class);
+    Mockito.doReturn(true)
+      .when(mock).isClientRunning();
+    Mockito.doReturn((int)FAST_GRACE_PERIOD)
+      .when(mock).getHdfsTimeout();
+    Mockito.doReturn("myclient")
+      .when(mock).getClientName();
+    return mock;
+  }
+
   @Test
   public void testInstanceSharing() throws IOException {
     // Two lease renewers with the same UGI should return
@@ -93,11 +103,11 @@ public void testClientName() throws IOException {
   public void testRenewal() throws Exception {
     // Keep track of how many times the lease gets renewed
     final AtomicInteger leaseRenewalCount = new AtomicInteger();
-    Mockito.doAnswer(new Answer<Void>() {
+    Mockito.doAnswer(new Answer<Boolean>() {
       @Override
-      public Void answer(InvocationOnMock invocation) throws Throwable {
+      public Boolean answer(InvocationOnMock invocation) throws Throwable {
         leaseRenewalCount.incrementAndGet();
-        return null;
+        return true;
       }
     }).when(MOCK_DFSCLIENT).renewLease();
 
@@ -120,6 +130,57 @@ public Void answer(InvocationOnMock invocation) throws Throwable {
     renewer.closeFile(filePath, MOCK_DFSCLIENT);
   }
   
+  /**
+   * Regression test for HDFS-2810. In this bug, the LeaseRenewer has handles
+   * to several DFSClients with the same name, the first of which has no files
+   * open. Previously, this was causing the lease to not get renewed.
+   */
+  @Test
+  public void testManyDfsClientsWhereSomeNotOpen() throws Exception {
+    // First DFSClient has no files open so doesn't renew leases.
+    final DFSClient mockClient1 = createMockClient();
+    Mockito.doReturn(false).when(mockClient1).renewLease();
+    assertSame(renewer, LeaseRenewer.getInstance(
+        FAKE_AUTHORITY, FAKE_UGI_A, mockClient1));
+    
+    // Set up a file so that we start renewing our lease.
+    DFSOutputStream mockStream1 = Mockito.mock(DFSOutputStream.class);
+    String filePath = "/foo";
+    renewer.put(filePath, mockStream1, mockClient1);
+
+    // Second DFSClient does renew lease
+    final DFSClient mockClient2 = createMockClient();
+    Mockito.doReturn(true).when(mockClient2).renewLease();
+    assertSame(renewer, LeaseRenewer.getInstance(
+        FAKE_AUTHORITY, FAKE_UGI_A, mockClient2));
+
+    // Set up a file so that we start renewing our lease.
+    DFSOutputStream mockStream2 = Mockito.mock(DFSOutputStream.class);
+    renewer.put(filePath, mockStream2, mockClient2);
+
+    
+    // Wait for lease to get renewed
+    GenericTestUtils.waitFor(new Supplier<Boolean>() {
+      @Override
+      public Boolean get() {
+        try {
+          Mockito.verify(mockClient1, Mockito.atLeastOnce()).renewLease();
+          Mockito.verify(mockClient2, Mockito.atLeastOnce()).renewLease();
+          return true;
+        } catch (AssertionError err) {
+          LeaseRenewer.LOG.warn("Not yet satisfied", err);
+          return false;
+        } catch (IOException e) {
+          // should not throw!
+          throw new RuntimeException(e);
+        }
+      }
+    }, 100, 10000);
+
+    renewer.closeFile(filePath, mockClient1);
+    renewer.closeFile(filePath, mockClient2);
+  }
+  
   @Test
   public void testThreadName() throws Exception {
     DFSOutputStream mockStream = Mockito.mock(DFSOutputStream.class);