HDFS-12985. NameNode crashes during restart after an OpenForWrite file present in the Snapshot got deleted.

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

@@ -523,6 +523,13 @@ public class INodeFile extends INodeWithAdditionalFields
     this.blocks = BlockInfo.EMPTY_ARRAY;
   }
 
+  private void updateRemovedUnderConstructionFiles(
+      ReclaimContext reclaimContext) {
+    if (isUnderConstruction() && reclaimContext.removedUCFiles != null) {
+      reclaimContext.removedUCFiles.add(getId());
+    }
+  }
+
   @Override
   public void cleanSubtree(ReclaimContext reclaimContext,
       final int snapshot, int priorSnapshotId) {
@@ -531,6 +538,7 @@ public class INodeFile extends INodeWithAdditionalFields
       // TODO: avoid calling getStoragePolicyID
       sf.cleanFile(reclaimContext, this, snapshot, priorSnapshotId,
           getStoragePolicyID());
+      updateRemovedUnderConstructionFiles(reclaimContext);
     } else {
       if (snapshot == CURRENT_STATE_ID) {
         if (priorSnapshotId == NO_SNAPSHOT_ID) {
@@ -543,9 +551,7 @@ public class INodeFile extends INodeWithAdditionalFields
           // clean the 0-sized block if the file is UC
           if (uc != null) {
             uc.cleanZeroSizeBlock(this, reclaimContext.collectedBlocks);
-            if (reclaimContext.removedUCFiles != null) {
+            updateRemovedUnderConstructionFiles(reclaimContext);
-              reclaimContext.removedUCFiles.add(getId());
-            }
           }
         }
       }
@@ -564,9 +570,7 @@ public class INodeFile extends INodeWithAdditionalFields
           reclaimContext.collectedBlocks);
       sf.clearDiffs();
     }
-    if (isUnderConstruction() && reclaimContext.removedUCFiles != null) {
+    updateRemovedUnderConstructionFiles(reclaimContext);
-      reclaimContext.removedUCFiles.add(getId());
-    }
   }
 
   public void clearFile(ReclaimContext reclaimContext) {

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

@@ -630,6 +630,51 @@ public class TestOpenFilesWithSnapshot {
     hbaseOutputStream.close();
   }
 
+  /**
+   * Verify if the NameNode can restart properly after an OpenForWrite
+   * file and the only snapshot it was present in were deleted.
+   *
+   * @throws Exception
+   */
+  @Test (timeout = 600000)
+  public void testOpenFileDeletionAndNNRestart() throws Exception {
+    // Construct the directory tree
+    final Path snapRootDir = new Path("/level_0_A/test");
+    final String hbaseFileName = "hbase.log";
+    final String snap1Name = "snap_1";
+
+    // Create a file with few blocks. Get its output stream
+    // for append.
+    final Path hbaseFile = new Path(snapRootDir, hbaseFileName);
+    createFile(hbaseFile);
+    FSDataOutputStream hbaseOutputStream = fs.append(hbaseFile);
+
+    int newWriteLength = (int) (BLOCKSIZE * 1.5);
+    byte[] buf = new byte[newWriteLength];
+    Random random = new Random();
+    random.nextBytes(buf);
+
+    // Write more data to the file
+    writeToStream(hbaseOutputStream, buf);
+
+    // Take a snapshot while the file is open for write
+    final Path snap1Dir = SnapshotTestHelper.createSnapshot(
+        fs, snapRootDir, snap1Name);
+    LOG.info("Open file status in snap: " +
+        fs.getFileStatus(new Path(snap1Dir, hbaseFileName)));
+
+    // Delete the open file and the snapshot while
+    // its output stream is still open.
+    fs.delete(hbaseFile, true);
+    fs.deleteSnapshot(snapRootDir, snap1Name);
+    Assert.assertFalse(fs.exists(hbaseFile));
+
+    // Verify file existence after the NameNode restart
+    cluster.restartNameNode();
+    cluster.waitActive();
+    Assert.assertFalse(fs.exists(hbaseFile));
+  }
+
   /**
    * Test client writing to open files are not interrupted when snapshots
    * that captured open files get deleted.