HDFS-12836. startTxId could be greater than endTxId when tailing in-progress edit log. Contributed by Chao Sun.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/qjournal/client/QuorumJournalManager.java

@@ -498,6 +498,12 @@ public class QuorumJournalManager implements JournalManager {
         // than committedTxnId. This ensures the consistency.
         if (onlyDurableTxns && inProgressOk) {
           endTxId = Math.min(endTxId, committedTxnId);
+          if (endTxId < remoteLog.getStartTxId()) {
+            LOG.warn("Found endTxId (" + endTxId + ") that is less than " +
+                "the startTxId (" + remoteLog.getStartTxId() +
+                ") - setting it to startTxId.");
+            endTxId = remoteLog.getStartTxId();
+          }
         }
 
         EditLogInputStream elis = EditLogFileInputStream.fromUrl(

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

@@ -309,6 +309,25 @@ public class TestStandbyInProgressTail {
     assertNotNull(NameNodeAdapter.getFileInfo(nn1, "/test3", true));
   }
 
+  @Test
+  public void testNonUniformConfig() throws Exception {
+    // Test case where some NNs (in this case the active NN) in the cluster
+    // do not have in-progress tailing enabled.
+    Configuration newConf = cluster.getNameNode(0).getConf();
+    newConf.setBoolean(
+        DFSConfigKeys.DFS_HA_TAILEDITS_INPROGRESS_KEY,
+        false);
+    cluster.restartNameNode(0);
+    cluster.transitionToActive(0);
+
+    cluster.getNameNode(0).getRpcServer().mkdirs("/test",
+        FsPermission.createImmutable((short) 0755), true);
+    cluster.getNameNode(0).getRpcServer().rollEdits();
+
+    cluster.getNameNode(1).getNamesystem().getEditLogTailer().doTailEdits();
+    assertNotNull(NameNodeAdapter.getFileInfo(nn1, "/test", true));
+  }
+
   /**
    * Check that no edits files are present in the given storage dirs.
    */