HDFS-14028. HDFS OIV temporary dir deletes folder.

Contributed by Adam Antal.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/offlineImageViewer/PBImageTextWriter.java

@@ -20,7 +20,6 @@ package org.apache.hadoop.hdfs.tools.offlineImageViewer;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Lists;
-import org.apache.commons.io.FileUtils;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.fs.permission.PermissionStatus;
@@ -298,7 +297,8 @@ abstract class PBImageTextWriter implements Closeable {
     LevelDBMetadataMap(String baseDir) throws IOException {
       File dbDir = new File(baseDir);
       if (dbDir.exists()) {
-        FileUtils.deleteDirectory(dbDir);
+        throw new IOException("Folder " + dbDir + " already exists! Delete " +
+            "manually or provide another (not existing) directory!");
       }
       if (!dbDir.mkdirs()) {
         throw new IOException("Failed to mkdir on " + dbDir);

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/tools/offlineImageViewer/TestOfflineImageViewer.java

@@ -669,6 +669,25 @@ public class TestOfflineImageViewer {
     }
   }
 
+  @Test(expected = IOException.class)
+  public void testDelimitedWithExistingFolder() throws IOException,
+      InterruptedException {
+    File tempDelimitedDir = null;
+    try {
+      String tempDelimitedDirName = "tempDirDelimited";
+      String tempDelimitedDirPath = new FileSystemTestHelper().
+          getTestRootDir() + "/" + tempDelimitedDirName;
+      tempDelimitedDir = new File(tempDelimitedDirPath);
+      Assert.assertTrue("Couldn't create temp directory!",
+          tempDelimitedDir.mkdirs());
+      testPBDelimitedWriter(tempDelimitedDirPath);
+    } finally {
+      if (tempDelimitedDir != null) {
+        FileUtils.deleteDirectory(tempDelimitedDir);
+      }
+    }
+  }
+
   private void testPBDelimitedWriter(String db)
       throws IOException, InterruptedException {
     final String DELIMITER = "\t";