HDFS-3049. During the normal NN startup process, fall back on a different edit log if we see one that is corrupt. Contributed by Colin Patrick McCabe.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1349114 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -90,6 +90,9 @@ Trunk (unreleased changes)
     HDFS-3040. TestMulitipleNNDataBlockScanner is misspelled. (Madhukara Phatak
     via atm)
 
+    HDFS-3049. During the normal NN startup process, fall back on a different
+    edit log if we see one that is corrupt (Colin Patrick McCabe via todd)
+
   OPTIMIZATIONS
 
   BUG FIXES

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

@@ -1173,18 +1173,6 @@ public class FSEditLog  {
         throw e;
       }
     }
-    // This code will go away as soon as RedundantEditLogInputStream is
-    // introduced. (HDFS-3049)
-    try {
-      if (!streams.isEmpty()) {
-        streams.get(0).skipUntil(fromTxId);
-      }
-    } catch (IOException e) {
-      // We don't want to throw an exception from here, because that would make
-      // recovery impossible even if the user requested it.  An exception will
-      // be thrown later, when we don't read the starting txid we expect.
-      LOG.error("error skipping until transaction " + fromTxId, e);
-    }
     return streams;
   }
   

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

@@ -668,7 +668,9 @@ public class FSEditLogLoader {
         FSImage.LOG.warn("Caught exception after reading " + numValid +
             " ops from " + in + " while determining its valid length." +
             "Position was " + lastPos, t);
-        break;
+        in.resync();
+        FSImage.LOG.warn("After resync, position is " + in.getPosition());
+        continue;
       }
       if (lastTxId == HdfsConstants.INVALID_TXID
           || op.getTransactionId() > lastTxId) {

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

@@ -24,7 +24,9 @@ import java.util.Collections;
 import java.util.Comparator;
 import java.util.LinkedList;
 import java.util.List;
+import java.util.PriorityQueue;
 import java.util.SortedSet;
+import java.util.TreeSet;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -40,7 +42,6 @@ import com.google.common.collect.ImmutableListMultimap;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Multimaps;
 import com.google.common.collect.Sets;
-import com.google.common.collect.TreeMultiset;
 
 /**
  * Manages a collection of Journals. None of the methods are synchronized, it is
@@ -222,8 +223,9 @@ public class JournalSet implements JournalManager {
   @Override
   public void selectInputStreams(Collection<EditLogInputStream> streams,
       long fromTxId, boolean inProgressOk) {
-    final TreeMultiset<EditLogInputStream> allStreams =
-        TreeMultiset.create(EDIT_LOG_INPUT_STREAM_COMPARATOR);
+    final PriorityQueue<EditLogInputStream> allStreams = 
+        new PriorityQueue<EditLogInputStream>(64,
+            EDIT_LOG_INPUT_STREAM_COMPARATOR);
     for (JournalAndStream jas : journals) {
       if (jas.isDisabled()) {
         LOG.info("Skipping jas " + jas + " since it's disabled");
@@ -239,7 +241,8 @@ public class JournalSet implements JournalManager {
     // transaction ID.
     LinkedList<EditLogInputStream> acc =
         new LinkedList<EditLogInputStream>();
-    for (EditLogInputStream elis : allStreams) {
+    EditLogInputStream elis;
+    while ((elis = allStreams.poll()) != null) {
       if (acc.isEmpty()) {
         acc.add(elis);
       } else {
@@ -247,7 +250,7 @@ public class JournalSet implements JournalManager {
         if (accFirstTxId == elis.getFirstTxId()) {
           acc.add(elis);
         } else if (accFirstTxId < elis.getFirstTxId()) {
-          streams.add(acc.get(0));
+          streams.add(new RedundantEditLogInputStream(acc, fromTxId));
           acc.clear();
           acc.add(elis);
         } else if (accFirstTxId > elis.getFirstTxId()) {
@@ -258,7 +261,7 @@ public class JournalSet implements JournalManager {
       }
     }
     if (!acc.isEmpty()) {
-      streams.add(acc.get(0));
+      streams.add(new RedundantEditLogInputStream(acc, fromTxId));
       acc.clear();
     }
   }

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

@@ -0,0 +1,276 @@
+/**
+ * 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.server.namenode;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
+
+import org.apache.commons.lang.StringUtils;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.hdfs.protocol.HdfsConstants;
+import org.apache.hadoop.io.IOUtils;
+
+import com.google.common.base.Preconditions;
+import com.google.common.primitives.Longs;
+
+/**
+ * A merged input stream that handles failover between different edit logs.
+ *
+ * We will currently try each edit log stream exactly once.  In other words, we
+ * don't handle the "ping pong" scenario where different edit logs contain a
+ * different subset of the available edits.
+ */
+class RedundantEditLogInputStream extends EditLogInputStream {
+  public static final Log LOG = LogFactory.getLog(EditLogInputStream.class.getName());
+  private int curIdx;
+  private long prevTxId;
+  private final EditLogInputStream[] streams;
+
+  /**
+   * States that the RedundantEditLogInputStream can be in.
+   *
+   * <pre>
+   *                   start (if no streams)
+   *                           |
+   *                           V
+   * PrematureEOFException  +----------------+
+   *        +-------------->| EOF            |<--------------+
+   *        |               +----------------+               |
+   *        |                                                |
+   *        |          start (if there are streams)          |
+   *        |                  |                             |
+   *        |                  V                             | EOF
+   *        |   resync      +----------------+ skipUntil  +---------+
+   *        |   +---------->| SKIP_UNTIL     |----------->|  OK     |
+   *        |   |           +----------------+            +---------+
+   *        |   |                | IOE   ^ fail over to      | IOE
+   *        |   |                V       | next stream       |
+   * +----------------------+   +----------------+           |
+   * | STREAM_FAILED_RESYNC |   | STREAM_FAILED  |<----------+
+   * +----------------------+   +----------------+
+   *                  ^   Recovery mode    |
+   *                  +--------------------+
+   * </pre>
+   */
+  static private enum State {
+    /** We need to skip until prevTxId + 1 */
+    SKIP_UNTIL,
+    /** We're ready to read opcodes out of the current stream */
+    OK,
+    /** The current stream has failed. */
+    STREAM_FAILED,
+    /** The current stream has failed, and resync() was called.  */
+    STREAM_FAILED_RESYNC,
+    /** There are no more opcodes to read from this
+     * RedundantEditLogInputStream */
+    EOF;
+  }
+
+  private State state;
+  private IOException prevException;
+
+  RedundantEditLogInputStream(Collection<EditLogInputStream> streams,
+      long startTxId) {
+    this.curIdx = 0;
+    this.prevTxId = (startTxId == HdfsConstants.INVALID_TXID) ?
+      HdfsConstants.INVALID_TXID : (startTxId - 1);
+    this.state = (streams.isEmpty()) ? State.EOF : State.SKIP_UNTIL;
+    this.prevException = null;
+    // EditLogInputStreams in a RedundantEditLogInputStream must be finalized,
+    // and can't be pre-transactional.
+    EditLogInputStream first = null;
+    for (EditLogInputStream s : streams) {
+      Preconditions.checkArgument(s.getFirstTxId() !=
+          HdfsConstants.INVALID_TXID, "invalid first txid in stream: %s", s);
+      Preconditions.checkArgument(s.getLastTxId() !=
+          HdfsConstants.INVALID_TXID, "invalid last txid in stream: %s", s);
+      if (first == null) {
+        first = s;
+      } else {
+        Preconditions.checkArgument(s.getFirstTxId() == first.getFirstTxId(),
+          "All streams in the RedundantEditLogInputStream must have the same " +
+          "start transaction ID!  " + first + " had start txId " +
+          first.getFirstTxId() + ", but " + s + " had start txId " +
+          s.getFirstTxId());
+      }
+    }
+
+    this.streams = streams.toArray(new EditLogInputStream[0]);
+
+    // We sort the streams here so that the streams that end later come first.
+    Arrays.sort(this.streams, new Comparator<EditLogInputStream>() {
+      @Override
+      public int compare(EditLogInputStream a, EditLogInputStream b) {
+        return Longs.compare(b.getLastTxId(), a.getLastTxId());
+      }
+    });
+  }
+
+  @Override
+  public String getName() {
+    StringBuilder bld = new StringBuilder();
+    String prefix = "";
+    for (EditLogInputStream elis : streams) {
+      bld.append(prefix);
+      bld.append(elis.getName());
+      prefix = ", ";
+    }
+    return bld.toString();
+  }
+
+  @Override
+  public long getFirstTxId() {
+    return streams[curIdx].getFirstTxId();
+  }
+
+  @Override
+  public long getLastTxId() {
+    return streams[curIdx].getLastTxId();
+  }
+
+  @Override
+  public void close() throws IOException {
+    IOUtils.cleanup(LOG,  streams);
+  }
+
+  @Override
+  protected FSEditLogOp nextValidOp() {
+    try {
+      if (state == State.STREAM_FAILED) {
+        state = State.STREAM_FAILED_RESYNC;
+      }
+      return nextOp();
+    } catch (IOException e) {
+      return null;
+    }
+  }
+
+  @Override
+  protected FSEditLogOp nextOp() throws IOException {
+    while (true) {
+      switch (state) {
+      case SKIP_UNTIL:
+       try {
+          if (prevTxId != HdfsConstants.INVALID_TXID) {
+            LOG.info("Fast-forwarding stream '" + streams[curIdx].getName() +
+                "' to transaction ID " + (prevTxId + 1));
+            streams[curIdx].skipUntil(prevTxId + 1);
+          }
+        } catch (IOException e) {
+          prevException = e;
+          state = State.STREAM_FAILED;
+        }
+        state = State.OK;
+        break;
+      case OK:
+        try {
+          FSEditLogOp op = streams[curIdx].readOp();
+          if (op == null) {
+            state = State.EOF;
+            if (streams[curIdx].getLastTxId() == prevTxId) {
+              return null;
+            } else {
+              throw new PrematureEOFException("got premature end-of-file " +
+                  "at txid " + prevTxId + "; expected file to go up to " +
+                  streams[curIdx].getLastTxId());
+            }
+          }
+          prevTxId = op.getTransactionId();
+          return op;
+        } catch (IOException e) {
+          prevException = e;
+          state = State.STREAM_FAILED;
+        }
+        break;
+      case STREAM_FAILED:
+        if (curIdx + 1 == streams.length) {
+          throw prevException;
+        }
+        long oldLast = streams[curIdx].getLastTxId();
+        long newLast = streams[curIdx + 1].getLastTxId();
+        if (newLast < oldLast) {
+          throw new IOException("We encountered an error reading " +
+              streams[curIdx].getName() + ".  During automatic edit log " +
+              "failover, we noticed that all of the remaining edit log " +
+              "streams are shorter than the current one!  The best " +
+              "remaining edit log ends at transaction " +
+              newLast + ", but we thought we could read up to transaction " +
+              oldLast + ".  If you continue, metadata will be lost forever!");
+        }
+        LOG.error("Got error reading edit log input stream " +
+          streams[curIdx].getName() + "; failing over to edit log " +
+          streams[curIdx + 1].getName(), prevException);
+        curIdx++;
+        state = State.SKIP_UNTIL;
+        break;
+      case STREAM_FAILED_RESYNC:
+        if (curIdx + 1 == streams.length) {
+          if (prevException instanceof PrematureEOFException) {
+            // bypass early EOF check
+            state = State.EOF;
+          } else {
+            streams[curIdx].resync();
+            state = State.SKIP_UNTIL;
+          }
+        } else {
+          LOG.error("failing over to edit log " +
+              streams[curIdx + 1].getName());
+          curIdx++;
+          state = State.SKIP_UNTIL;
+        }
+        break;
+      case EOF:
+        return null;
+      }
+    }
+  }
+
+  @Override
+  public int getVersion() throws IOException {
+    return streams[curIdx].getVersion();
+  }
+
+  @Override
+  public long getPosition() {
+    return streams[curIdx].getPosition();
+  }
+
+  @Override
+  public long length() throws IOException {
+    return streams[curIdx].length();
+  }
+
+  @Override
+  public boolean isInProgress() {
+    return streams[curIdx].isInProgress();
+  }
+
+  static private final class PrematureEOFException extends IOException {
+    private static final long serialVersionUID = 1L;
+    PrematureEOFException(String msg) {
+      super(msg);
+    }
+  }
+}

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

@@ -134,6 +134,7 @@ public class MiniDFSCluster {
     private boolean format = true;
     private boolean manageNameDfsDirs = true;
     private boolean manageNameDfsSharedDirs = true;
+    private boolean enableManagedDfsDirsRedundancy = true;
     private boolean manageDataDfsDirs = true;
     private StartupOption option = null;
     private String[] racks = null; 
@@ -196,6 +197,14 @@ public class MiniDFSCluster {
       return this;
     }
 
+    /**
+     * Default: true
+     */
+    public Builder enableManagedDfsDirsRedundancy(boolean val) {
+      this.enableManagedDfsDirsRedundancy = val;
+      return this;
+    }
+
     /**
      * Default: true
      */
@@ -298,6 +307,7 @@ public class MiniDFSCluster {
                        builder.format,
                        builder.manageNameDfsDirs,
                        builder.manageNameDfsSharedDirs,
+                       builder.enableManagedDfsDirsRedundancy,
                        builder.manageDataDfsDirs,
                        builder.option,
                        builder.racks,
@@ -385,7 +395,7 @@ public class MiniDFSCluster {
   public MiniDFSCluster(Configuration conf,
                         int numDataNodes,
                         StartupOption nameNodeOperation) throws IOException {
-    this(0, conf, numDataNodes, false, false, false,  nameNodeOperation, 
+    this(0, conf, numDataNodes, false, false, false, false,  nameNodeOperation, 
           null, null, null);
   }
   
@@ -407,7 +417,8 @@ public class MiniDFSCluster {
                         int numDataNodes,
                         boolean format,
                         String[] racks) throws IOException {
-    this(0, conf, numDataNodes, format, true, true,  null, racks, null, null);
+    this(0, conf, numDataNodes, format, true, true, true, null,
+        racks, null, null);
   }
   
   /**
@@ -429,7 +440,8 @@ public class MiniDFSCluster {
                         int numDataNodes,
                         boolean format,
                         String[] racks, String[] hosts) throws IOException {
-    this(0, conf, numDataNodes, format, true, true, null, racks, hosts, null);
+    this(0, conf, numDataNodes, format, true, true, true, null,
+        racks, hosts, null);
   }
   
   /**
@@ -462,8 +474,8 @@ public class MiniDFSCluster {
                         boolean manageDfsDirs,
                         StartupOption operation,
                         String[] racks) throws IOException {
-    this(nameNodePort, conf, numDataNodes, format, manageDfsDirs, manageDfsDirs,
-         operation, racks, null, null);
+    this(nameNodePort, conf, numDataNodes, format, manageDfsDirs,
+        manageDfsDirs, manageDfsDirs, operation, racks, null, null);
   }
 
   /**
@@ -497,7 +509,7 @@ public class MiniDFSCluster {
                         String[] racks,
                         long[] simulatedCapacities) throws IOException {
     this(nameNodePort, conf, numDataNodes, format, manageDfsDirs, manageDfsDirs,
-          operation, racks, null, simulatedCapacities);
+        manageDfsDirs, operation, racks, null, simulatedCapacities);
   }
   
   /**
@@ -531,13 +543,15 @@ public class MiniDFSCluster {
                         int numDataNodes,
                         boolean format,
                         boolean manageNameDfsDirs,
+                        boolean enableManagedDfsDirsRedundancy,
                         boolean manageDataDfsDirs,
                         StartupOption operation,
                         String[] racks, String hosts[],
                         long[] simulatedCapacities) throws IOException {
     this.nameNodes = new NameNodeInfo[1]; // Single namenode in the cluster
     initMiniDFSCluster(conf, numDataNodes, format,
-        manageNameDfsDirs, true, manageDataDfsDirs, operation, racks, hosts,
+        manageNameDfsDirs, true, enableManagedDfsDirsRedundancy, manageDataDfsDirs,
+        operation, racks, hosts,
         simulatedCapacities, null, true, false,
         MiniDFSNNTopology.simpleSingleNN(nameNodePort, 0));
   }
@@ -545,8 +559,8 @@ public class MiniDFSCluster {
   private void initMiniDFSCluster(
       Configuration conf,
       int numDataNodes, boolean format, boolean manageNameDfsDirs,
-      boolean manageNameDfsSharedDirs, boolean manageDataDfsDirs,
-      StartupOption operation, String[] racks,
+      boolean manageNameDfsSharedDirs, boolean enableManagedDfsDirsRedundancy,
+      boolean manageDataDfsDirs, StartupOption operation, String[] racks,
       String[] hosts, long[] simulatedCapacities, String clusterId,
       boolean waitSafeMode, boolean setupHostsFile,
       MiniDFSNNTopology nnTopology)
@@ -586,6 +600,7 @@ public class MiniDFSCluster {
     federation = nnTopology.isFederated();
     createNameNodesAndSetConf(
         nnTopology, manageNameDfsDirs, manageNameDfsSharedDirs,
+        enableManagedDfsDirsRedundancy,
         format, operation, clusterId, conf);
     
     if (format) {
@@ -608,7 +623,8 @@ public class MiniDFSCluster {
   
   private void createNameNodesAndSetConf(MiniDFSNNTopology nnTopology,
       boolean manageNameDfsDirs, boolean manageNameDfsSharedDirs,
-      boolean format, StartupOption operation, String clusterId,
+      boolean enableManagedDfsDirsRedundancy, boolean format,
+      StartupOption operation, String clusterId,
       Configuration conf) throws IOException {
     Preconditions.checkArgument(nnTopology.countNameNodes() > 0,
         "empty NN topology: no namenodes specified!");
@@ -664,7 +680,7 @@ public class MiniDFSCluster {
       Collection<URI> prevNNDirs = null;
       int nnCounterForFormat = nnCounter;
       for (NNConf nn : nameservice.getNNs()) {
-        initNameNodeConf(conf, nsId, nn.getNnId(), manageNameDfsDirs,
+        initNameNodeConf(conf, nsId, nn.getNnId(), manageNameDfsDirs, manageNameDfsDirs,
             nnCounterForFormat);
         Collection<URI> namespaceDirs = FSNamesystem.getNamespaceDirs(conf);
         if (format) {
@@ -696,7 +712,8 @@ public class MiniDFSCluster {
 
       // Start all Namenodes
       for (NNConf nn : nameservice.getNNs()) {
-        initNameNodeConf(conf, nsId, nn.getNnId(), manageNameDfsDirs, nnCounter);
+        initNameNodeConf(conf, nsId, nn.getNnId(), manageNameDfsDirs,
+            enableManagedDfsDirsRedundancy, nnCounter);
         createNameNode(nnCounter++, conf, numDataNodes, false, operation,
             clusterId, nsId, nn.getNnId());
       }
@@ -721,8 +738,8 @@ public class MiniDFSCluster {
 
   private void initNameNodeConf(Configuration conf,
       String nameserviceId, String nnId,
-      boolean manageNameDfsDirs, int nnIndex)
-      throws IOException {
+      boolean manageNameDfsDirs, boolean enableManagedDfsDirsRedundancy,
+      int nnIndex) throws IOException {
     if (nameserviceId != null) {
       conf.set(DFS_NAMESERVICE_ID, nameserviceId);
     }
@@ -731,12 +748,21 @@ public class MiniDFSCluster {
     }
     
     if (manageNameDfsDirs) {
-      conf.set(DFS_NAMENODE_NAME_DIR_KEY,
-          fileAsURI(new File(base_dir, "name" + (2*nnIndex + 1)))+","+
-          fileAsURI(new File(base_dir, "name" + (2*nnIndex + 2))));
-      conf.set(DFS_NAMENODE_CHECKPOINT_DIR_KEY,
-          fileAsURI(new File(base_dir, "namesecondary" + (2*nnIndex + 1)))+","+
-          fileAsURI(new File(base_dir, "namesecondary" + (2*nnIndex + 2))));
+      if (enableManagedDfsDirsRedundancy) {
+        conf.set(DFS_NAMENODE_NAME_DIR_KEY,
+            fileAsURI(new File(base_dir, "name" + (2*nnIndex + 1)))+","+
+            fileAsURI(new File(base_dir, "name" + (2*nnIndex + 2))));
+        conf.set(DFS_NAMENODE_CHECKPOINT_DIR_KEY,
+            fileAsURI(new File(base_dir, "namesecondary" + (2*nnIndex + 1)))+","+
+            fileAsURI(new File(base_dir, "namesecondary" + (2*nnIndex + 2))));
+      } else {
+        conf.set(DFS_NAMENODE_NAME_DIR_KEY,
+            fileAsURI(new File(base_dir, "name" + (2*nnIndex + 1))).
+              toString());
+        conf.set(DFS_NAMENODE_CHECKPOINT_DIR_KEY,
+            fileAsURI(new File(base_dir, "namesecondary" + (2*nnIndex + 1))).
+              toString());
+      }
     }
   }
 
@@ -2134,7 +2160,7 @@ public class MiniDFSCluster {
     String nnId = null;
     initNameNodeAddress(conf, nameserviceId,
         new NNConf(nnId).setIpcPort(namenodePort));
-    initNameNodeConf(conf, nameserviceId, nnId, true, nnIndex);
+    initNameNodeConf(conf, nameserviceId, nnId, true, true, nnIndex);
     createNameNode(nnIndex, conf, numDataNodes, true, null, null,
         nameserviceId, nnId);
 

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

@@ -506,21 +506,29 @@ public class TestEditLog extends TestCase {
     FSImage fsimage = namesystem.getFSImage();
     final FSEditLog editLog = fsimage.getEditLog();
     fileSys.mkdirs(new Path("/tmp"));
-    StorageDirectory sd = fsimage.getStorage().dirIterator(NameNodeDirType.EDITS).next();
+
+    Iterator<StorageDirectory> iter = fsimage.getStorage().
+      dirIterator(NameNodeDirType.EDITS);
+    LinkedList<StorageDirectory> sds = new LinkedList<StorageDirectory>();
+    while (iter.hasNext()) {
+      sds.add(iter.next());
+    }
     editLog.close();
     cluster.shutdown();
 
-    File editFile = NNStorage.getFinalizedEditsFile(sd, 1, 3);
-    assertTrue(editFile.exists());
+    for (StorageDirectory sd : sds) {
+      File editFile = NNStorage.getFinalizedEditsFile(sd, 1, 3);
+      assertTrue(editFile.exists());
   
-    long fileLen = editFile.length();
-    System.out.println("File name: " + editFile + " len: " + fileLen);
-    RandomAccessFile rwf = new RandomAccessFile(editFile, "rw");
-    rwf.seek(fileLen-4); // seek to checksum bytes
-    int b = rwf.readInt();
-    rwf.seek(fileLen-4);
-    rwf.writeInt(b+1);
-    rwf.close();
+      long fileLen = editFile.length();
+      LOG.debug("Corrupting Log File: " + editFile + " len: " + fileLen);
+      RandomAccessFile rwf = new RandomAccessFile(editFile, "rw");
+      rwf.seek(fileLen-4); // seek to checksum bytes
+      int b = rwf.readInt();
+      rwf.seek(fileLen-4);
+      rwf.writeInt(b+1);
+      rwf.close();
+    }
     
     try {
       cluster = new MiniDFSCluster.Builder(conf).numDataNodes(NUM_DATA_NODES).format(false).build();
@@ -1232,6 +1240,113 @@ public class TestEditLog extends TestCase {
     }
   }
 
+  private static long readAllEdits(Collection<EditLogInputStream> streams,
+      long startTxId) throws IOException {
+    FSEditLogOp op;
+    long nextTxId = startTxId;
+    long numTx = 0;
+    for (EditLogInputStream s : streams) {
+      while (true) {
+        op = s.readOp();
+        if (op == null)
+          break;
+        if (op.getTransactionId() != nextTxId) {
+          throw new IOException("out of order transaction ID!  expected " +
+              nextTxId + " but got " + op.getTransactionId() + " when " +
+              "reading " + s.getName());
+        }
+        numTx++;
+        nextTxId = op.getTransactionId() + 1;
+      }
+    }
+    return numTx;
+  }
+
+  /**
+   * Test edit log failover.  If a single edit log is missing, other 
+   * edits logs should be used instead.
+   */
+  @Test
+  public void testEditLogFailOverFromMissing() throws IOException {
+    File f1 = new File(TEST_DIR + "/failover0");
+    File f2 = new File(TEST_DIR + "/failover1");
+    List<URI> editUris = ImmutableList.of(f1.toURI(), f2.toURI());
+
+    NNStorage storage = setupEdits(editUris, 3);
+    
+    final long startErrorTxId = 1*TXNS_PER_ROLL + 1;
+    final long endErrorTxId = 2*TXNS_PER_ROLL;
+
+    File[] files = new File(f1, "current").listFiles(new FilenameFilter() {
+        public boolean accept(File dir, String name) {
+          if (name.startsWith(NNStorage.getFinalizedEditsFileName(startErrorTxId, 
+                                  endErrorTxId))) {
+            return true;
+          }
+          return false;
+        }
+      });
+    assertEquals(1, files.length);
+    assertTrue(files[0].delete());
+
+    FSEditLog editlog = getFSEditLog(storage);
+    editlog.initJournalsForWrite();
+    long startTxId = 1;
+    try {
+      readAllEdits(editlog.selectInputStreams(startTxId, 4*TXNS_PER_ROLL),
+          startTxId);
+    } catch (IOException e) {
+      LOG.error("edit log failover didn't work", e);
+      fail("Edit log failover didn't work");
+    }
+  }
+
+  /** 
+   * Test edit log failover from a corrupt edit log
+   */
+  @Test
+  public void testEditLogFailOverFromCorrupt() throws IOException {
+    File f1 = new File(TEST_DIR + "/failover0");
+    File f2 = new File(TEST_DIR + "/failover1");
+    List<URI> editUris = ImmutableList.of(f1.toURI(), f2.toURI());
+
+    NNStorage storage = setupEdits(editUris, 3);
+    
+    final long startErrorTxId = 1*TXNS_PER_ROLL + 1;
+    final long endErrorTxId = 2*TXNS_PER_ROLL;
+
+    File[] files = new File(f1, "current").listFiles(new FilenameFilter() {
+        public boolean accept(File dir, String name) {
+          if (name.startsWith(NNStorage.getFinalizedEditsFileName(startErrorTxId, 
+                                  endErrorTxId))) {
+            return true;
+          }
+          return false;
+        }
+      });
+    assertEquals(1, files.length);
+
+    long fileLen = files[0].length();
+    LOG.debug("Corrupting Log File: " + files[0] + " len: " + fileLen);
+    RandomAccessFile rwf = new RandomAccessFile(files[0], "rw");
+    rwf.seek(fileLen-4); // seek to checksum bytes
+    int b = rwf.readInt();
+    rwf.seek(fileLen-4);
+    rwf.writeInt(b+1);
+    rwf.close();
+    
+    FSEditLog editlog = getFSEditLog(storage);
+    editlog.initJournalsForWrite();
+    long startTxId = 1;
+    try {
+      readAllEdits(editlog.selectInputStreams(startTxId, 4*TXNS_PER_ROLL),
+          startTxId);
+    } catch (IOException e) {
+      LOG.error("edit log failover didn't work", e);
+      fail("Edit log failover didn't work");
+    }
+  }
+
   /**
    * Test creating a directory with lots and lots of edit log segments
    */

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

@@ -50,6 +50,16 @@ public class TestEditLogFileOutputStream {
     TEST_EDITS.delete();
   }
 
+  @Test
+  public void testConstants() {
+    // Each call to FSEditLogOp#Reader#readOp can read at most MAX_OP_SIZE bytes
+    // before getting an exception.  So we don't want to preallocate a longer
+    // region than MAX_OP_SIZE, because then we'd get an IOException when reading
+    // through the padding at the end of the file.
+    assertTrue(EditLogFileOutputStream.PREALLOCATION_LENGTH <
+        FSEditLogOp.MAX_OP_SIZE);
+  }
+
   @Test
   public void testPreallocation() throws IOException {
     Configuration conf = new HdfsConfiguration();

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

@@ -77,7 +77,7 @@ public class TestFSEditLogLoader {
     MiniDFSCluster cluster = null;
     FileSystem fileSys = null;
     cluster = new MiniDFSCluster.Builder(conf).numDataNodes(NUM_DATA_NODES)
-        .build();
+        .enableManagedDfsDirsRedundancy(false).build();
     cluster.waitActive();
     fileSys = cluster.getFileSystem();
     final FSNamesystem namesystem = cluster.getNamesystem();
@@ -107,7 +107,7 @@ public class TestFSEditLogLoader {
     bld.append("Recent opcode offsets: (\\d+\\s*){4}$");
     try {
       cluster = new MiniDFSCluster.Builder(conf).numDataNodes(NUM_DATA_NODES)
-          .format(false).build();
+          .enableManagedDfsDirsRedundancy(false).format(false).build();
       fail("should not be able to start");
     } catch (IOException e) {
       assertTrue("error message contains opcodes message",
@@ -326,6 +326,56 @@ public class TestFSEditLogLoader {
     assertTrue(validation.hasCorruptHeader());
   }
 
+  @Test
+  public void testValidateEditLogWithCorruptBody() throws IOException {
+    File testDir = new File(TEST_DIR, "testValidateEditLogWithCorruptBody");
+    SortedMap<Long, Long> offsetToTxId = Maps.newTreeMap();
+    final int NUM_TXNS = 20;
+    File logFile = prepareUnfinalizedTestEditLog(testDir, NUM_TXNS,
+        offsetToTxId);
+    // Back up the uncorrupted log
+    File logFileBak = new File(testDir, logFile.getName() + ".bak");
+    Files.copy(logFile, logFileBak);
+    EditLogValidation validation =
+        EditLogFileInputStream.validateEditLog(logFile);
+    assertTrue(!validation.hasCorruptHeader());
+    // We expect that there will be an OP_START_LOG_SEGMENT, followed by
+    // NUM_TXNS opcodes, followed by an OP_END_LOG_SEGMENT.
+    assertEquals(NUM_TXNS + 1, validation.getEndTxId());
+    // Corrupt each edit and verify that validation continues to work
+    for (Map.Entry<Long, Long> entry : offsetToTxId.entrySet()) {
+      long txOffset = entry.getKey();
+      long txId = entry.getValue();
+
+      // Restore backup, corrupt the txn opcode
+      Files.copy(logFileBak, logFile);
+      corruptByteInFile(logFile, txOffset);
+      validation = EditLogFileInputStream.validateEditLog(logFile);
+      long expectedEndTxId = (txId == (NUM_TXNS + 1)) ?
+          NUM_TXNS : (NUM_TXNS + 1);
+      assertEquals("Failed when corrupting txn opcode at " + txOffset,
+          expectedEndTxId, validation.getEndTxId());
+      assertTrue(!validation.hasCorruptHeader());
+    }
+
+    // Truncate right before each edit and verify that validation continues
+    // to work
+    for (Map.Entry<Long, Long> entry : offsetToTxId.entrySet()) {
+      long txOffset = entry.getKey();
+      long txId = entry.getValue();
+
+      // Restore backup, corrupt the txn opcode
+      Files.copy(logFileBak, logFile);
+      truncateFile(logFile, txOffset);
+      validation = EditLogFileInputStream.validateEditLog(logFile);
+      long expectedEndTxId = (txId == 0) ?
+          HdfsConstants.INVALID_TXID : (txId - 1);
+      assertEquals("Failed when corrupting txid " + txId + " txn opcode " +
+        "at " + txOffset, expectedEndTxId, validation.getEndTxId());
+      assertTrue(!validation.hasCorruptHeader());
+    }
+  }
+
   @Test
   public void testValidateEmptyEditLog() throws IOException {
     File testDir = new File(TEST_DIR, "testValidateEmptyEditLog");

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

@@ -20,10 +20,10 @@ package org.apache.hadoop.hdfs.server.namenode;
 import static org.junit.Assert.*;
 
 import java.net.URI;
-import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.Iterator;
+import java.util.PriorityQueue;
 
 import java.io.RandomAccessFile;
 import java.io.File;
@@ -33,7 +33,6 @@ import org.junit.Test;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.fs.FileUtil;
-import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.server.common.Storage.StorageDirectory;
 import org.apache.hadoop.hdfs.server.namenode.JournalManager.CorruptionException;
 import org.apache.hadoop.hdfs.server.namenode.NNStorage.NameNodeDirType;
@@ -45,7 +44,6 @@ import static org.apache.hadoop.hdfs.server.namenode.TestEditLog.TXNS_PER_ROLL;
 import static org.apache.hadoop.hdfs.server.namenode.TestEditLog.TXNS_PER_FAIL;
 
 import com.google.common.collect.ImmutableList;
-import com.google.common.collect.TreeMultiset;
 import com.google.common.base.Joiner;
 
 public class TestFileJournalManager {
@@ -64,12 +62,13 @@ public class TestFileJournalManager {
   static long getNumberOfTransactions(FileJournalManager jm, long fromTxId,
       boolean inProgressOk, boolean abortOnGap) throws IOException {
     long numTransactions = 0, txId = fromTxId;
-    final TreeMultiset<EditLogInputStream> allStreams =
-        TreeMultiset.create(JournalSet.EDIT_LOG_INPUT_STREAM_COMPARATOR);
+    final PriorityQueue<EditLogInputStream> allStreams = 
+        new PriorityQueue<EditLogInputStream>(64,
+            JournalSet.EDIT_LOG_INPUT_STREAM_COMPARATOR);
     jm.selectInputStreams(allStreams, fromTxId, inProgressOk);
-
+    EditLogInputStream elis = null;
     try {
-      for (EditLogInputStream elis : allStreams) {
+      while ((elis = allStreams.poll()) != null) {
         elis.skipUntil(txId);
         while (true) {
           FSEditLogOp op = elis.readOp();
@@ -87,6 +86,7 @@ public class TestFileJournalManager {
       }
     } finally {
       IOUtils.cleanup(LOG, allStreams.toArray(new EditLogInputStream[0]));
+      IOUtils.cleanup(LOG, elis);
     }
     return numTransactions;
   }
@@ -379,27 +379,28 @@ public class TestFileJournalManager {
   
   private static EditLogInputStream getJournalInputStream(JournalManager jm,
       long txId, boolean inProgressOk) throws IOException {
-    final TreeMultiset<EditLogInputStream> allStreams =
-        TreeMultiset.create(JournalSet.EDIT_LOG_INPUT_STREAM_COMPARATOR);
+    final PriorityQueue<EditLogInputStream> allStreams = 
+        new PriorityQueue<EditLogInputStream>(64,
+            JournalSet.EDIT_LOG_INPUT_STREAM_COMPARATOR);
     jm.selectInputStreams(allStreams, txId, inProgressOk);
+    EditLogInputStream elis = null, ret;
     try {
-      for (Iterator<EditLogInputStream> iter = allStreams.iterator();
-          iter.hasNext();) {
-        EditLogInputStream elis = iter.next();
+      while ((elis = allStreams.poll()) != null) {
         if (elis.getFirstTxId() > txId) {
           break;
         }
         if (elis.getLastTxId() < txId) {
-          iter.remove();
           elis.close();
           continue;
         }
         elis.skipUntil(txId);
-        iter.remove();
-        return elis;
+        ret = elis;
+        elis = null;
+        return ret;
       }
     } finally {
       IOUtils.cleanup(LOG,  allStreams.toArray(new EditLogInputStream[0]));
+      IOUtils.cleanup(LOG,  elis);
     }
     return null;
   }

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

@@ -343,7 +343,7 @@ public class TestNameNodeRecovery {
     StorageDirectory sd = null;
     try {
       cluster = new MiniDFSCluster.Builder(conf).numDataNodes(0)
-          .build();
+          .enableManagedDfsDirsRedundancy(false).build();
       cluster.waitActive();
       if (!finalize) {
         // Normally, the in-progress edit log would be finalized by
@@ -379,7 +379,7 @@ public class TestNameNodeRecovery {
     try {
       LOG.debug("trying to start normally (this should fail)...");
       cluster = new MiniDFSCluster.Builder(conf).numDataNodes(0)
-          .format(false).build();
+          .enableManagedDfsDirsRedundancy(false).format(false).build();
       cluster.waitActive();
       cluster.shutdown();
       if (needRecovery) {
@@ -404,7 +404,8 @@ public class TestNameNodeRecovery {
     try {
       LOG.debug("running recovery...");
       cluster = new MiniDFSCluster.Builder(conf).numDataNodes(0)
-          .format(false).startupOption(recoverStartOpt).build();
+          .enableManagedDfsDirsRedundancy(false).format(false)
+          .startupOption(recoverStartOpt).build();
     } catch (IOException e) {
       fail("caught IOException while trying to recover. " +
           "message was " + e.getMessage() +
@@ -420,7 +421,7 @@ public class TestNameNodeRecovery {
     try {
       LOG.debug("starting cluster normally after recovery...");
       cluster = new MiniDFSCluster.Builder(conf).numDataNodes(0)
-          .format(false).build();
+          .enableManagedDfsDirsRedundancy(false).format(false).build();
       LOG.debug("successfully recovered the " + corruptor.getName() +
           " corrupted edit log");
       cluster.waitActive();