HDFS-15998. Fix NullPointException In listOpenFiles (#3036)

Co-authored-by: huhaiyang <huhaiyang@didichuxing.com>
(cherry picked from commit b38b00e528)

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

@@ -1953,8 +1953,14 @@ public class FSNamesystem implements Namesystem, FSNamesystemMBean,
           continue;
         }
         Preconditions.checkState(ucFile instanceof INodeFile);
-        openFileIds.add(ucFileId);
+
         INodeFile inodeFile = ucFile.asFile();
+        if (!inodeFile.isUnderConstruction()) {
+          LOG.warn("The file {} is not under construction but has lease.",
+              inodeFile.getFullPathName());
+          continue;
+        }
+        openFileIds.add(ucFileId);
 
         String fullPathName = inodeFile.getFullPathName();
         if (org.apache.commons.lang3.StringUtils.isEmpty(path)

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

@@ -300,8 +300,13 @@ public class LeaseManager {
     Iterator<Long> inodeIdIterator = inodeIds.iterator();
     while (inodeIdIterator.hasNext()) {
       Long inodeId = inodeIdIterator.next();
-      final INodeFile inodeFile =
+      INode ucFile = fsnamesystem.getFSDirectory().getInode(inodeId);
-          fsnamesystem.getFSDirectory().getInode(inodeId).asFile();
+      if (ucFile == null) {
+        //probably got deleted
+        continue;
+      }
+
+      final INodeFile inodeFile = ucFile.asFile();
       if (!inodeFile.isUnderConstruction()) {
         LOG.warn("The file {} is not under construction but has lease.",
             inodeFile.getFullPathName());

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

@@ -37,6 +37,7 @@ import java.util.Scanner;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.regex.Pattern;
+import java.util.EnumSet;
 
 import java.util.function.Supplier;
 import org.apache.hadoop.thirdparty.com.google.common.collect.Lists;
@@ -46,6 +47,7 @@ import org.apache.hadoop.fs.CommonConfigurationKeys;
 import org.apache.hadoop.fs.FSDataOutputStream;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.fs.BatchedRemoteIterator.BatchedEntries;
 import org.apache.hadoop.hdfs.client.HdfsDataInputStream;
 import org.apache.hadoop.hdfs.client.HdfsDataOutputStream;
 import org.apache.hadoop.hdfs.protocol.DatanodeID;
@@ -55,6 +57,8 @@ import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.DatanodeReportType;
 import org.apache.hadoop.hdfs.protocol.LocatedBlock;
 import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
+import org.apache.hadoop.hdfs.protocol.OpenFileEntry;
+import org.apache.hadoop.hdfs.protocol.OpenFilesIterator;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfo;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockManager;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockManagerTestUtil;
@@ -867,6 +871,69 @@ public class TestDecommission extends AdminStatesBaseTest {
         closedFileSet, openFilesMap, 0);
   }
 
+  /**
+   * Verify Decommission In Progress with List Open Files
+   * 1. start decommissioning a node (set LeavingServiceStatus)
+   * 2. close file with decommissioning
+   * @throws Exception
+   */
+  @Test(timeout=180000)
+  public void testDecommissionWithCloseFileAndListOpenFiles()
+      throws Exception {
+    LOG.info("Starting test testDecommissionWithCloseFileAndListOpenFiles");
+
+    // Disable redundancy monitor check so that open files blocking
+    // decommission can be listed and verified.
+    getConf().setInt(
+        DFSConfigKeys.DFS_NAMENODE_REDUNDANCY_INTERVAL_SECONDS_KEY, 1000);
+    getConf().setLong(
+        DFSConfigKeys.DFS_NAMENODE_LIST_OPENFILES_NUM_RESPONSES, 1);
+
+    startSimpleCluster(1, 3);
+    FileSystem fileSys = getCluster().getFileSystem(0);
+    FSNamesystem ns = getCluster().getNamesystem(0);
+    Path file = new Path("/openFile");
+    FSDataOutputStream st = AdminStatesBaseTest.writeIncompleteFile(fileSys,
+        file, (short)3, (short)(fileSize / blockSize));
+    for (DataNode d: getCluster().getDataNodes()) {
+      DataNodeTestUtils.triggerBlockReport(d);
+    }
+
+    LocatedBlocks lbs = NameNodeAdapter.getBlockLocations(
+        getCluster().getNameNode(0), file.toUri().getPath(),
+        0, blockSize * 10);
+    DatanodeInfo dnToDecommission = lbs.getLastLocatedBlock().getLocations()[0];
+
+    DatanodeManager dm = ns.getBlockManager().getDatanodeManager();
+    dnToDecommission = dm.getDatanode(dnToDecommission.getDatanodeUuid());
+    initExcludeHost(dnToDecommission.getXferAddr());
+    refreshNodes(0);
+    BlockManagerTestUtil.recheckDecommissionState(dm);
+    waitNodeState(dnToDecommission, AdminStates.DECOMMISSION_INPROGRESS);
+    Thread.sleep(3000);
+    //Make sure DatanodeAdminMonitor(DatanodeAdminBackoffMonitor) At least twice run.
+
+    BatchedEntries<OpenFileEntry> batchedListEntries = getCluster().
+        getNameNodeRpc(0).listOpenFiles(0,
+        EnumSet.of(OpenFilesIterator.OpenFilesType.BLOCKING_DECOMMISSION),
+        OpenFilesIterator.FILTER_PATH_DEFAULT);
+    assertEquals(1, batchedListEntries.size());
+    st.close(); //close file
+
+    try {
+      batchedListEntries = getCluster().getNameNodeRpc().listOpenFiles(0,
+          EnumSet.of(OpenFilesIterator.OpenFilesType.BLOCKING_DECOMMISSION),
+          OpenFilesIterator.FILTER_PATH_DEFAULT);
+      assertEquals(0, batchedListEntries.size());
+    } catch (NullPointerException e) {
+      Assert.fail("Should not throw NPE when the file is not under " +
+          "construction but has lease!");
+    }
+    initExcludeHost("");
+    refreshNodes(0);
+    fileSys.delete(file, false);
+  }
+
   @Test(timeout = 360000)
   public void testDecommissionWithOpenFileAndBlockRecovery()
       throws IOException, InterruptedException {

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

@@ -54,9 +54,11 @@ import org.apache.hadoop.hdfs.HdfsConfiguration;
 import org.apache.hadoop.hdfs.MiniDFSCluster;
 import org.apache.hadoop.hdfs.tools.DFSAdmin;
 import org.apache.hadoop.util.ToolRunner;
+import org.apache.hadoop.util.ChunkedArrayList;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
+import org.junit.Assert;
 
 /**
  * Verify open files listing.
@@ -321,4 +323,33 @@ public class TestListOpenFiles {
                 "hdfs://non-cluster/"));
     fs.listOpenFiles(EnumSet.of(OpenFilesType.ALL_OPEN_FILES), "/path");
   }
+
+  @Test
+  public void testListOpenFilesWithDeletedPath() throws Exception {
+    HashMap<Path, FSDataOutputStream> openFiles = new HashMap<>();
+    openFiles.putAll(
+        DFSTestUtil.createOpenFiles(fs, new Path("/"), "open-1", 1));
+    BatchedEntries<OpenFileEntry> openFileEntryBatchedEntries = nnRpc
+        .listOpenFiles(0, EnumSet.of(OpenFilesType.ALL_OPEN_FILES),
+        OpenFilesIterator.FILTER_PATH_DEFAULT);
+    assertEquals(1, openFileEntryBatchedEntries.size());
+    String path = openFileEntryBatchedEntries.get(0).getFilePath();
+    FSNamesystem fsNamesystem = cluster.getNamesystem();
+    FSDirectory dir = fsNamesystem.getFSDirectory();
+    List<INode> removedINodes = new ChunkedArrayList<>();
+    removedINodes.add(dir.getINode(path));
+    fsNamesystem.writeLock();
+    try {
+      dir.removeFromInodeMap(removedINodes);
+      openFileEntryBatchedEntries = nnRpc
+          .listOpenFiles(0, EnumSet.of(OpenFilesType.ALL_OPEN_FILES),
+          OpenFilesIterator.FILTER_PATH_DEFAULT);
+      assertEquals(0, openFileEntryBatchedEntries.size());
+      fsNamesystem.leaseManager.removeLease(dir.getINode(path).getId());
+    } catch (NullPointerException e) {
+      Assert.fail("Should not throw NPE when the file is deleted but has lease!");
+    } finally {
+      fsNamesystem.writeUnlock();
+    }
+  }
 }