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From d472c4bc5ff1cb72d6ecb0d691f239b9088378dc Mon Sep 17 00:00:00 2001
Date: Fri, 22 Jan 2021 11:35:09 +0800
Subject: Backport of JDK-8166253
summary: (ch) FileLock object can get GC'd and result in unexpected release of file lock
LLT: jdk/test/java/nio/channels/FileLock/FileLockGC.java
bug link: https://bugs.openjdk.java.net/browse/JDK-8166253
---
.../classes/sun/nio/ch/FileLockTable.java | 13 +-
.../nio/channels/FileLock/FileLockGC.java | 143 ++++++++++++++++++
2 files changed, 155 insertions(+), 1 deletion(-)
create mode 100644 jdk/test/java/nio/channels/FileLock/FileLockGC.java
diff --git a/jdk/src/share/classes/sun/nio/ch/FileLockTable.java b/jdk/src/share/classes/sun/nio/ch/FileLockTable.java
index e77e1c4ce..b0351e566 100644
--- a/jdk/src/share/classes/sun/nio/ch/FileLockTable.java
+++ b/jdk/src/share/classes/sun/nio/ch/FileLockTable.java
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2005, 2009, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2018, 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
@@ -115,9 +115,13 @@ class SharedFileLockTable extends FileLockTable {
// File key for the file that this channel is connected to
private final FileKey fileKey;
+ // Locks obtained for this channel
+ private final Set<FileLock> locks;
+
SharedFileLockTable(Channel channel, FileDescriptor fd) throws IOException {
this.channel = channel;
this.fileKey = FileKey.create(fd);
+ this.locks = new HashSet<FileLock>();
}
@Override
@@ -135,6 +139,7 @@ class SharedFileLockTable extends FileLockTable {
if (prev == null) {
// we successfully created the key so we add the file lock
list.add(new FileLockReference(fl, queue, fileKey));
+ locks.add(fl);
break;
}
}
@@ -151,6 +156,7 @@ class SharedFileLockTable extends FileLockTable {
if (list == current) {
checkList(list, fl.position(), fl.size());
list.add(new FileLockReference(fl, queue, fileKey));
+ locks.add(fl);
break;
}
list = current;
@@ -187,6 +193,7 @@ class SharedFileLockTable extends FileLockTable {
assert (lock != null) && (lock.acquiredBy() == channel);
ref.clear();
list.remove(index);
+ locks.remove(fl);
break;
}
index++;
@@ -220,6 +227,8 @@ class SharedFileLockTable extends FileLockTable {
// once the lock list is empty we remove it from the map
removeKeyIfEmpty(fileKey, list);
+
+ locks.clear();
}
}
return result;
@@ -238,6 +247,8 @@ class SharedFileLockTable extends FileLockTable {
if (lock == fromLock) {
ref.clear();
list.set(index, new FileLockReference(toLock, queue, fileKey));
+ locks.remove(fromLock);
+ locks.add(toLock);
break;
}
}
diff --git a/jdk/test/java/nio/channels/FileLock/FileLockGC.java b/jdk/test/java/nio/channels/FileLock/FileLockGC.java
new file mode 100644
index 000000000..fb6618688
--- /dev/null
+++ b/jdk/test/java/nio/channels/FileLock/FileLockGC.java
@@ -0,0 +1,143 @@
+/*
+ * Copyright (c) 2018, 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.
+ */
+
+import java.io.File;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.lang.ref.Reference;
+import java.lang.ref.WeakReference;
+import java.nio.channels.FileLock;
+import java.nio.channels.OverlappingFileLockException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import jdk.testlibrary.FileUtils;
+
+/*
+ * @test
+ * @bug 8166253
+ * @summary Verify that OverlappingFileLockException is thrown when expected.
+ * @library /lib/testlibrary
+ * @build jdk.testlibrary.Utils
+ * @run main/othervm FileLockGC
+ */
+public class FileLockGC {
+ public enum TestType {
+ NO_GC_NO_RELEASE(true),
+ // A hypothetical 'GC_THEN_RELEASE' case is infeasible
+ RELEASE(false),
+ RELEASE_THEN_GC(false),
+ GC(true);
+
+ private final boolean exceptionExpected;
+
+ TestType(boolean exceptionExpected) {
+ this.exceptionExpected = exceptionExpected;
+ }
+
+ boolean exceptionExpected() {
+ return exceptionExpected;
+ }
+ }
+
+ public static void main(String[] args) throws Exception {
+ final File f = new File(System.getProperty("test.dir", ".")
+ + File.separator + "junk.txt");
+ final Path p = f.toPath();
+ int failures = 0;
+
+ for (TestType t : TestType.values()) {
+ try {
+ if (!testFileLockGC(f, t)) {
+ failures++;
+ }
+ } finally {
+ FileUtils.deleteFileIfExistsWithRetry(p);
+ }
+ }
+
+ if (failures != 0) {
+ throw new RuntimeException("Test had " + failures + " failure(s)");
+ }
+ }
+
+ private static boolean testFileLockGC(File f, TestType type)
+ throws InterruptedException, IOException {
+ System.out.printf("Test %s starting%n", type.toString());
+
+ final RandomAccessFile raf1 = new RandomAccessFile(f, "rw");
+
+ FileLock lock1 = raf1.getChannel().tryLock();
+ WeakReference<FileLock> ref1 = new WeakReference(lock1);
+
+ switch (type) {
+ case GC:
+ lock1 = null;
+ System.gc();
+ break;
+ case RELEASE:
+ lock1.release();
+ break;
+ case RELEASE_THEN_GC:
+ lock1.release();
+ lock1 = null;
+ System.gc();
+ break;
+ default: // NO_GC_NO_RELEASE
+ // lock1 is neither collected nor released
+ break;
+ }
+
+ final RandomAccessFile raf2 = new RandomAccessFile(f, "rw");
+
+ boolean success = true;
+ FileLock lock2 = null;
+ try {
+ lock2 = raf2.getChannel().tryLock();
+ if (type.exceptionExpected()) {
+ System.err.printf
+ ("No expected OverlappingFileLockException for test %s%n",
+ type.toString());
+ success = false;
+ }
+ } catch (OverlappingFileLockException ofe) {
+ if (!type.exceptionExpected()) {
+ System.err.printf
+ ("Unexpected OverlappingFileLockException for test %s%n",
+ type.toString());
+ success = false;
+ }
+ } finally {
+ if (lock1 != null) {
+ lock1.release();
+ }
+ if (lock2 != null) {
+ lock2.release();
+ }
+ raf2.close();
+ raf1.close();
+ System.out.printf("Test %s finished%n", type.toString());
+ }
+
+ return success;
+ }
+}
--
2.19.0
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