--- /dev/null	2017-04-27 11:02:11.338611058 -0700
+++ new/test/java/nio/channels/FileChannel/directio/PwriteDirect.java	2017-08-09 14:53:27.899811189 -0700
@@ -0,0 +1,158 @@
+/*
+ * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/* @test
+ * @bug 8164900
+ * @summary Test positional write method of FileChannel with DirectIO
+ * (use -Dseed=X to set PRNG seed)
+ * @library .. /test/lib
+ * @build jdk.test.lib.RandomFactory
+ * @run main PwriteDirect
+ * @key randomness
+ */
+
+import java.io.*;
+import java.nio.ByteBuffer;
+import java.nio.CharBuffer;
+import java.nio.channels.*;
+import java.nio.channels.FileChannel;
+import java.util.Random;
+import java.nio.file.Paths;
+import java.nio.file.Path;
+import java.nio.file.Files;
+import java.nio.file.FileStore;
+import java.nio.file.StandardOpenOption;
+import com.sun.nio.file.ExtendedOpenOption;
+
+import jdk.test.lib.RandomFactory;
+
+/**
+ * Testing FileChannel's positional write method.
+ */
+public class PwriteDirect {
+
+    private static Random generator = RandomFactory.getRandom();
+
+    public static void main(String[] args) throws Exception {
+        genericTest();
+        testUnwritableChannel();
+    }
+
+    private static void testUnwritableChannel() throws Exception {
+        Path p = Files.createTempFile(Paths.get(
+                System.getProperty("test.dir", ".")), "test", null);
+        OutputStream fos = Files.newOutputStream(p);
+        fos.write(new byte[4096]);
+        fos.close();
+
+        FileChannel fc = FileChannel.open(p, ExtendedOpenOption.DIRECT);
+
+        try {
+            fc.write(ByteBuffer.allocate(4096),0);
+            throw new RuntimeException("Expected exception not thrown");
+        } catch(NonWritableChannelException e) {
+            // Correct result
+        } finally {
+            fc.close();
+            Files.delete(p);
+        }
+    }
+
+    private static void genericTest() throws Exception {
+        Path p = Files.createTempFile(Paths.get(
+                System.getProperty("test.dir", ".")), "test", null);
+        initTestFile(p);
+
+        FileChannel c = FileChannel.open(p, StandardOpenOption.WRITE,
+                StandardOpenOption.READ, ExtendedOpenOption.DIRECT);
+        FileStore fs = Files.getFileStore(p);
+        int alignment = (int)fs.getBlockSize();
+
+        for (int x=0; x<100; x++) {
+            long offset = generator.nextInt(100) * 4096;
+            ByteBuffer block = ByteBuffer.allocateDirect(4096 + alignment - 1)
+                                         .alignedSlice(alignment);
+
+            // Write known sequence out
+            for (byte i=0; i<4; i++) {
+                block.put(i);
+            }
+            block.position(0);
+            long originalPosition = c.position();
+            int totalWritten = 0;
+            while (totalWritten < 4096) {
+                int written = c.write(block, offset);
+                if (written < 0)
+                    throw new Exception("Write failed");
+                totalWritten += written;
+            }
+
+            long newPosition = c.position();
+
+            // Ensure that file pointer position has not changed
+            if (originalPosition != newPosition)
+                throw new Exception("File position modified");
+
+            // Attempt to read sequence back in
+            block = ByteBuffer.allocateDirect(4096 + alignment - 1)
+                              .alignedSlice(alignment);
+            originalPosition = c.position();
+            int totalRead = 0;
+            while (totalRead < 4096) {
+                int read = c.read(block, offset);
+                if (read < 0)
+                    throw new Exception("Read failed");
+                totalRead += read;
+            }
+            newPosition = c.position();
+
+            // Ensure that file pointer position has not changed
+            if (originalPosition != newPosition)
+                throw new Exception("File position modified");
+
+            for (byte i=0; i<4; i++) {
+                if (block.get(i) != i)
+                    throw new Exception("Write test failed");
+            }
+        }
+        c.close();
+        Files.delete(p);
+    }
+
+    private static void initTestFile(Path p) throws Exception {
+        OutputStream fos = Files.newOutputStream(p);
+        BufferedWriter awriter
+            = new BufferedWriter(new OutputStreamWriter(fos, "8859_1"));
+
+        for(int i=0; i<100; i++) {
+            String number = new Integer(i).toString();
+            for (int h=0; h<4-number.length(); h++)
+                awriter.write("0");
+            awriter.write(""+i);
+            for (int j=0; j < 4092; j++)
+                awriter.write("0");
+        }
+       awriter.flush();
+       awriter.close();
+    }
+}