--- old/src/java.base/share/classes/sun/nio/ch/FileChannelImpl.java	2017-08-09 14:53:21.974811133 -0700
+++ new/src/java.base/share/classes/sun/nio/ch/FileChannelImpl.java	2017-08-09 14:53:21.868811132 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 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
@@ -40,6 +40,11 @@
 import java.nio.channels.ReadableByteChannel;
 import java.nio.channels.SelectableChannel;
 import java.nio.channels.WritableByteChannel;
+import java.nio.file.Files;
+import java.nio.file.FileStore;
+import java.nio.file.FileSystemException;
+import java.nio.file.Path;
+import java.nio.file.Paths;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -85,15 +90,27 @@
     // Positional-read is not interruptible
     private volatile boolean uninterruptible;
 
+    //directIO
+    private final boolean direct;
+
+    //IO alignment for DirectIO
+    private final int alignment;
+
     private FileChannelImpl(FileDescriptor fd, String path, boolean readable,
-                            boolean writable, Object parent)
+                            boolean writable, boolean direct, Object parent)
     {
         this.fd = fd;
         this.readable = readable;
         this.writable = writable;
         this.parent = parent;
         this.path = path;
+        this.direct = direct;
         this.nd = new FileDispatcherImpl();
+        if (direct) {
+            this.alignment = nd.setDirectIO(fd, path);
+        } else {
+            this.alignment = -1;
+        }
     }
 
     // Used by FileInputStream.getChannel(), FileOutputStream.getChannel
@@ -102,7 +119,14 @@
                                    boolean readable, boolean writable,
                                    Object parent)
     {
-        return new FileChannelImpl(fd, path, readable, writable, parent);
+        return new FileChannelImpl(fd, path, readable, writable, false, parent);
+    }
+
+    public static FileChannel open(FileDescriptor fd, String path,
+                                   boolean readable, boolean writable,
+                                   boolean direct, Object parent)
+    {
+        return new FileChannelImpl(fd, path, readable, writable, direct, parent);
     }
 
     private void ensureOpen() throws IOException {
@@ -150,6 +174,16 @@
     }
 
     public int read(ByteBuffer dst) throws IOException {
+        if (direct) {
+            if (dst.remaining() % alignment != 0) {
+               throw new IOException("Number of remaining bytes is not "
+                                     + "a multiple of the block size");
+            }
+            if (position() % alignment != 0) {
+               throw new IOException("Channel position is not a multiple "
+                                     + "of the block size");
+            }
+        }
         ensureOpen();
         if (!readable)
             throw new NonReadableChannelException();
@@ -162,7 +196,7 @@
                 if (!isOpen())
                     return 0;
                 do {
-                    n = IOUtil.read(fd, dst, -1, nd);
+                    n = IOUtil.read(fd, dst, -1, direct, alignment, nd);
                 } while ((n == IOStatus.INTERRUPTED) && isOpen());
                 return IOStatus.normalize(n);
             } finally {
@@ -178,6 +212,19 @@
     {
         if ((offset < 0) || (length < 0) || (offset > dsts.length - length))
             throw new IndexOutOfBoundsException();
+
+        if (direct && (position() % alignment != 0))
+            throw new IOException("Channel position is not "
+                                  + "a multiple of the block size");
+
+        int i = offset;
+        while (i < dsts.length) {
+            if (direct && (dsts[i].remaining() % alignment != 0))
+                throw new IOException("Number of remaining bytes is not "
+                                      + "a multiple of the block size");
+            i++;
+        }
+
         ensureOpen();
         if (!readable)
             throw new NonReadableChannelException();
@@ -190,7 +237,8 @@
                 if (!isOpen())
                     return 0;
                 do {
-                    n = IOUtil.read(fd, dsts, offset, length, nd);
+                    n = IOUtil.read(fd, dsts, offset, length,
+                            direct, alignment, nd);
                 } while ((n == IOStatus.INTERRUPTED) && isOpen());
                 return IOStatus.normalize(n);
             } finally {
@@ -205,6 +253,16 @@
         ensureOpen();
         if (!writable)
             throw new NonWritableChannelException();
+        if (direct) {
+            if (src.remaining() % alignment != 0) {
+               throw new IOException("Number of remaining bytes is not "
+                                     + "a multiple of the block size");
+            }
+            if (position() % alignment != 0) {
+               throw new IOException("Channel position is not a multiple "
+                                     + "of the block size");
+            }
+        }
         synchronized (positionLock) {
             int n = 0;
             int ti = -1;
@@ -214,7 +272,7 @@
                 if (!isOpen())
                     return 0;
                 do {
-                    n = IOUtil.write(fd, src, -1, nd);
+                    n = IOUtil.write(fd, src, -1, direct, alignment, nd);
                 } while ((n == IOStatus.INTERRUPTED) && isOpen());
                 return IOStatus.normalize(n);
             } finally {
@@ -233,6 +291,19 @@
         ensureOpen();
         if (!writable)
             throw new NonWritableChannelException();
+
+        if (direct && (position() % alignment != 0))
+            throw new IOException("Channel position is not a multiple "
+                                  + " of the block size");
+
+        int i = offset;
+        while (i < srcs.length) {
+            if (direct && (srcs[i].remaining() % alignment != 0))
+                throw new IOException("Number of remaining bytes is not "
+                                      + "a multiple of the block size");
+            i++;
+        }
+
         synchronized (positionLock) {
             long n = 0;
             int ti = -1;
@@ -242,7 +313,8 @@
                 if (!isOpen())
                     return 0;
                 do {
-                    n = IOUtil.write(fd, srcs, offset, length, nd);
+                    n = IOUtil.write(fd, srcs, offset, length,
+                            direct, alignment, nd);
                 } while ((n == IOStatus.INTERRUPTED) && isOpen());
                 return IOStatus.normalize(n);
             } finally {
@@ -725,6 +797,17 @@
             throw new IllegalArgumentException("Negative position");
         if (!readable)
             throw new NonReadableChannelException();
+        if (direct) {
+            if (dst.remaining() % alignment != 0) {
+                throw new IOException("Remaining number of bytes is not "
+                                      + "a multiple of the block size");
+            }
+            if (position % alignment != 0) {
+                throw new IOException("Channel position is not a multiple "
+                                      + "of the block size");
+            }
+        }
+
         ensureOpen();
         if (nd.needsPositionLock()) {
             synchronized (positionLock) {
@@ -747,7 +830,7 @@
             if (!isOpen())
                 return -1;
             do {
-                n = IOUtil.read(fd, dst, position, nd);
+                n = IOUtil.read(fd, dst, position, direct, alignment, nd);
             } while ((n == IOStatus.INTERRUPTED) && isOpen());
             return IOStatus.normalize(n);
         } finally {
@@ -764,6 +847,16 @@
             throw new IllegalArgumentException("Negative position");
         if (!writable)
             throw new NonWritableChannelException();
+        if (direct) {
+            if (src.remaining() % alignment != 0) {
+                throw new IOException("Remaining number of bytes is not "
+                                      + "a multiple of the block size");
+            }
+            if (position % alignment != 0) {
+                throw new IOException("Channel position is not a multiple "
+                                      + "of the block size");
+            }
+        }
         ensureOpen();
         if (nd.needsPositionLock()) {
             synchronized (positionLock) {
@@ -784,7 +877,7 @@
             if (!isOpen())
                 return -1;
             do {
-                n = IOUtil.write(fd, src, position, nd);
+                n = IOUtil.write(fd, src, position, direct, alignment, nd);
             } while ((n == IOStatus.INTERRUPTED) && isOpen());
             return IOStatus.normalize(n);
         } finally {