6539707: (fc) MappedByteBuffer.force() method throws an IOException in a very simple test

Reviewed-by: alanb

src/java.base/share/classes/java/nio/MappedByteBuffer.java

@@ -26,6 +26,7 @@
 package java.nio;
 
 import java.io.FileDescriptor;
+import java.io.UncheckedIOException;
 import java.lang.ref.Reference;
 import java.util.Objects;
 
@@ -221,6 +222,10 @@ public abstract class MappedByteBuffer
      * mapping modes. This method may or may not have an effect for
      * implementation-specific mapping modes. </p>
      *
+     * @throws UncheckedIOException
+     *         If an I/O error occurs writing the buffer's content to the
+     *         storage device containing the mapped file
+     *
      * @return  This buffer
      */
     public final MappedByteBuffer force() {
@@ -272,6 +277,10 @@ public abstract class MappedByteBuffer
      *         if the preconditions on the index and length do not
      *         hold.
      *
+     * @throws UncheckedIOException
+     *         If an I/O error occurs writing the buffer's content to the
+     *         storage device containing the mapped file
+     *
      * @return  This buffer
      *
      * @since 13

src/java.base/share/classes/java/nio/MappedMemoryUtils.java

@@ -28,6 +28,8 @@ package java.nio;
 import jdk.internal.misc.Unsafe;
 
 import java.io.FileDescriptor;
+import java.io.IOException;
+import java.io.UncheckedIOException;
 
 /* package */ class MappedMemoryUtils {
 
@@ -94,7 +96,11 @@ import java.io.FileDescriptor;
         } else {
             // force writeback via file descriptor
             long offset = mappingOffset(address, index);
-            force0(fd, mappingAddress(address, offset, index), mappingLength(offset, length));
+            try {
+                force0(fd, mappingAddress(address, offset, index), mappingLength(offset, length));
+            } catch (IOException cause) {
+                throw new UncheckedIOException(cause);
+            }
         }
     }
 
@@ -103,7 +109,7 @@ import java.io.FileDescriptor;
     private static native boolean isLoaded0(long address, long length, int pageCount);
     private static native void load0(long address, long length);
     private static native void unload0(long address, long length);
-    private static native void force0(FileDescriptor fd, long address, long length);
+    private static native void force0(FileDescriptor fd, long address, long length) throws IOException;
 
     // utility methods
 

src/java.base/windows/native/libnio/MappedMemoryUtils.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2021, 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
@@ -76,7 +76,7 @@ Java_java_nio_MappedMemoryUtils_force0(JNIEnv *env, jobject obj, jobject fdo,
         if ((result != 0) || (GetLastError() != ERROR_LOCK_VIOLATION))
             break;
         retry++;
-    } while (retry < 3);
+    } while (retry < 5);
 
     /**
      * FlushViewOfFile only initiates the writing of dirty pages to disk

src/jdk.incubator.foreign/share/classes/jdk/incubator/foreign/MappedMemorySegments.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2021, 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
@@ -27,6 +27,7 @@ package jdk.incubator.foreign;
 
 import jdk.internal.foreign.MappedMemorySegmentImpl;
 
+import java.io.UncheckedIOException;
 import java.nio.MappedByteBuffer;
 import java.util.Objects;
 
@@ -149,6 +150,7 @@ public final class MappedMemorySegments {
      * and this method is called from a thread other than the segment's owner thread.
      * @throws UnsupportedOperationException if the given segment is not a mapped memory segment, e.g. if
      * {@code segment.isMapped() == false}.
+     * @throws UncheckedIOException if there is an I/O error writing the contents of the segment to the associated storage device
      */
     public static void force(MemorySegment segment) {
         toMappedSegment(segment).force();

test/jdk/java/nio/MappedByteBuffer/ForceException.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2021, 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 6539707
+ * @summary Test behavior of force() with respect to throwing exceptions
+ * @run main ForceException
+ */
+
+import java.io.File;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.io.UncheckedIOException;
+import java.nio.MappedByteBuffer;
+import java.nio.channels.FileChannel;
+
+public class ForceException {
+    public static void main(String[] args) throws IOException {
+        int blockSize = 2048 * 1024;
+        int numberOfBlocks = 200;
+        int fileLength = numberOfBlocks * blockSize;
+
+        File file = new File(System.getProperty("test.src", "."), "test.dat");
+        file.deleteOnExit();
+        try (RandomAccessFile raf = new RandomAccessFile(file, "rw")) {
+            raf.setLength(fileLength);
+
+            int pos = (numberOfBlocks - 1) * blockSize;
+            int size = (int)Math.min(blockSize, fileLength - pos);
+            MappedByteBuffer mbb =
+                raf.getChannel().map(FileChannel.MapMode.READ_WRITE, pos, size);
+
+            System.out.printf("Write region 0x%s..0x%s%n",
+                Long.toHexString(pos), Long.toHexString(size));
+            for (int k = 0; k < mbb.limit(); k++) {
+                mbb.put(k, (byte)65);
+            }
+
+            // Catch and process UncheckedIOException; other Throwables fail
+            try {
+                System.out.println("Force");
+                mbb.force();
+            } catch (UncheckedIOException legal) {
+                System.out.printf("Caught legal exception %s%n", legal);
+                IOException cause = legal.getCause(); // can't be null
+                // Throw the cause if flush failed (should be only on Windows)
+                if (cause.getMessage().startsWith("Flush failed")) {
+                    throw cause;
+                }
+            }
+
+            System.out.println("OK");
+        }
+    }
+}