HDFS-14674. [SBN read] Got an unexpected txid when tail editlog. Contributed by wangzhaohui.

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

@@ -893,7 +893,8 @@ public long loadEdits(Iterable<EditLogInputStream> editStreams,
     StartupProgress prog = NameNode.getStartupProgress();
     prog.beginPhase(Phase.LOADING_EDITS);
     
-    long prevLastAppliedTxId = lastAppliedTxId;  
+    long prevLastAppliedTxId = lastAppliedTxId;
+    long remainingReadTxns = maxTxnsToRead;
     try {    
       FSEditLogLoader loader = new FSEditLogLoader(target, lastAppliedTxId);
       
@@ -910,8 +911,8 @@ public long loadEdits(Iterable<EditLogInputStream> editStreams,
               (lastAppliedTxId + 1) + logSuppressed);
         }
         try {
-          loader.loadFSEdits(editIn, lastAppliedTxId + 1, maxTxnsToRead,
+          remainingReadTxns -= loader.loadFSEdits(editIn, lastAppliedTxId + 1,
-              startOpt, recovery);
+                  remainingReadTxns, startOpt, recovery);
         } finally {
           // Update lastAppliedTxId even in case of error, since some ops may
           // have been successfully applied before the error.
@@ -922,6 +923,9 @@ public long loadEdits(Iterable<EditLogInputStream> editStreams,
             && recovery != null) {
           lastAppliedTxId = editIn.getLastTxId();
         }
+        if (remainingReadTxns <= 0) {
+          break;
+        }
       }
     } finally {
       FSEditLog.closeAllStreams(editStreams);

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

@@ -307,6 +307,87 @@ private long testLoad(byte[] data, FSNamesystem namesys) throws IOException {
     return loader.loadFSEdits(new EditLogByteInputStream(data), 1);
   }
 
+  @Test
+  public void testMultiStreamsLoadEditWithConfMaxTxns()
+          throws IOException {
+    Configuration conf = getConf();
+    MiniDFSCluster cluster = null;
+    FileSystem fileSystem = null;
+    FSImage writeFsImage = null;
+    try {
+      cluster = new MiniDFSCluster
+              .Builder(conf)
+              .numDataNodes(NUM_DATA_NODES)
+              .build();
+      cluster.waitActive();
+      fileSystem = cluster.getFileSystem();
+      final FSNamesystem namesystem = cluster.getNamesystem();
+      writeFsImage = namesystem.getFSImage();
+      for (Iterator<URI> it = cluster.getNameDirs(0)
+              .iterator(); it.hasNext();) {
+        File dir = new File(it.next().getPath());
+        System.out.println(dir);
+      }
+      // Roll log so new output buffer size takes effect
+      // we should now be writing to edits_inprogress_3
+      long originalLastInodeId = namesystem.dir.getLastInodeId();
+      // Reopen some files as for append
+      Transactions trans = new Transactions(
+              namesystem, NUM_TRANSACTIONS, NUM_TRANSACTIONS / 2);
+      trans.run();
+      // Roll another time to finalize edits_inprogress_3
+      writeFsImage.rollEditLog(NameNodeLayoutVersion.CURRENT_LAYOUT_VERSION);
+      Transactions trans1 = new Transactions(
+              namesystem, NUM_TRANSACTIONS, NUM_TRANSACTIONS / 2);
+      trans1.run();
+      writeFsImage.rollEditLog(NameNodeLayoutVersion.CURRENT_LAYOUT_VERSION);
+      namesystem.dir.resetLastInodeIdWithoutChecking(originalLastInodeId);
+      for(Iterator<StorageDirectory> it = writeFsImage.getStorage().
+              dirIterator(NameNodeDirType.EDITS); it.hasNext();){
+        long expectedTxns = (2 * NUM_TRANSACTIONS) + 2;
+        File editFile = NNStorage.getFinalizedEditsFile(it.next(),
+                1, expectedTxns);
+        File editFile1 = NNStorage.getFinalizedEditsFile(it.next(),
+                203, 404);
+        assertTrue("Expect " + editFile + " exists", editFile.exists());
+        assertTrue("Expect " + editFile1 + " exists", editFile1.exists());
+        EditLogFileInputStream editLogFileInputStream1 =
+                new EditLogFileInputStream(editFile, 1, 202, false);
+        EditLogFileInputStream editLogFileInputStream2 =
+                new EditLogFileInputStream(editFile1, 203, 404, false);
+        List<EditLogInputStream> editStreams = Lists.newArrayList();
+        editStreams.add(editLogFileInputStream1);
+        editStreams.add(editLogFileInputStream2);
+        FSImage readFsImage = new FSImage(conf);
+        try {
+          readFsImage.loadEdits(editStreams, namesystem, 100, null, null);
+        } catch (Exception e){
+          LOG.error("There appears to be an out-of-order edit in the edit log",
+                  e.getMessage());
+          fail("no exception should be thrown");
+        } finally {
+          if (readFsImage != null) {
+            readFsImage.close();
+          }
+        }
+      }
+    } finally {
+      try {
+        if(fileSystem != null) {
+          fileSystem.close();
+        }
+        if(cluster != null) {
+          cluster.shutdown();
+        }
+        if(writeFsImage != null){
+          writeFsImage.close();
+        }
+      } catch (Throwable t) {
+        LOG.error("Couldn't shut down cleanly", t);
+      }
+    }
+  }
+
   /**
    * Simple test for writing to and rolling the edit log.
    */