The database file locking mechanism "FS" (;FILE_LOCK=FS) did not work on Linux…

The database file locking mechanism "FS" (;FILE_LOCK=FS) did not work on Linux since version 1.3.161.

h2/src/main/org/h2/store/FileStore.java

@@ -489,7 +489,7 @@ public class FileStore {
     public synchronized boolean tryLock() {
         try {
             lock = file.tryLock();
-            return true;
+            return lock != null;
         } catch (Exception e) {
             // ignore OverlappingFileLockException
             return false;

h2/src/test/org/h2/test/TestAll.java

@@ -132,6 +132,7 @@ import org.h2.test.unit.TestDateIso8601;
 import org.h2.test.unit.TestExit;
 import org.h2.test.unit.TestFile;
 import org.h2.test.unit.TestFileLock;
+import org.h2.test.unit.TestFileLockProcess;
 import org.h2.test.unit.TestFileLockSerialized;
 import org.h2.test.unit.TestFileSystem;
 import org.h2.test.unit.TestFtp;
@@ -344,18 +345,15 @@ java org.h2.test.TestAll timer
         System.setProperty("h2.delayWrongPasswordMax", "0");
         System.setProperty("h2.useThreadContextClassLoader", "true");
 
-        int testing;
         // System.setProperty("h2.modifyOnWrite", "true");
 
-        int testWith_TCP_PROTOCOL_VERSION_10;
-
-        int todoSupportTrailingSemicolonsInDatabaseUrl;
-
         // System.setProperty("h2.storeLocalTime", "true");
 
         // speedup
         // System.setProperty("h2.syncMethod", "");
 
+        int testMultiThreadedBackup;
+
 /*
 
 recovery tests with small freeList pages, page size 64
@@ -672,6 +670,7 @@ kill -9 `jps -l | grep "org.h2.test." | cut -d " " -f 1`
         new TestExit().runTest(this);
         new TestFile().runTest(this);
         new TestFileLock().runTest(this);
+        new TestFileLockProcess().runTest(this);
         new TestFileLockSerialized().runTest(this);
         new TestFtp().runTest(this);
         new TestFileSystem().runTest(this);

h2/src/test/org/h2/test/unit/TestFileLockProcess.java

+/*
+ * Copyright 2004-2011 H2 Group. Multiple-Licensed under the H2 License,
+ * Version 1.0, and under the Eclipse Public License, Version 1.0
+ * (http://h2database.com/html/license.html).
+ * Initial Developer: H2 Group
+ */
+package org.h2.test.unit;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.util.ArrayList;
+import org.h2.test.TestBase;
+import org.h2.test.utils.SelfDestructor;
+import org.h2.util.New;
+
+/**
+ * Tests database file locking.
+ * A new process is started.
+ */
+public class TestFileLockProcess extends TestBase {
+
+    /**
+     * This method is called when executing this application from the command
+     * line.
+     *
+     * @param args the command line parameters
+     */
+    public static void main(String... args) throws Exception {
+        SelfDestructor.startCountdown(60);
+        if (args.length == 0) {
+            TestBase.createCaller().init().test();
+            return;
+        }
+        String url = args[0];
+        TestFileLockProcess app = new TestFileLockProcess();
+        app.execute(url);
+    }
+
+    private void execute(String url) {
+        org.h2.Driver.load();
+        try {
+            Class.forName("org.h2.Driver");
+            Connection conn = DriverManager.getConnection(url);
+            System.out.println("!");
+            conn.close();
+        } catch (Exception e) {
+            // failed - expected
+        }
+    }
+
+    public void test() throws Exception {
+        if (config.codeCoverage || config.networked) {
+            return;
+        }
+        if (getBaseDir().indexOf(':') > 0) {
+            return;
+        }
+        deleteDb("lock");
+        String url = "jdbc:h2:"+getBaseDir()+"/lock";
+        test(50, url);
+        println("socket");
+        test(4, url + ";file_lock=socket");
+        println("fs");
+        test(4, url + ";file_lock=fs");
+        deleteDb("lock");
+    }
+
+    public void test(int count, String url) throws Exception {
+        Connection conn = DriverManager.getConnection(url);
+        String selfDestruct = SelfDestructor.getPropertyString(60);
+        String[] procDef = { "java", selfDestruct,
+                "-cp", getClassPath(),
+                getClass().getName(), url };
+        ArrayList<Process> processes = New.arrayList();
+        for (int i = 0; i < count; i++) {
+            Thread.sleep(100);
+            if (i % 10 == 0) {
+                println(i + "/" + count);
+            }
+            Process proc = Runtime.getRuntime().exec(procDef);
+            processes.add(proc);
+        }
+        for (int i = 0; i < count; i++) {
+            Process proc = processes.get(i);
+            StringBuilder buff = new StringBuilder();
+            while (true) {
+                int ch = proc.getErrorStream().read();
+                if (ch < 0) {
+                    break;
+                }
+                System.out.print((char) ch);
+                buff.append((char) ch);
+            }
+            while (true) {
+                int ch = proc.getInputStream().read();
+                if (ch < 0) {
+                    break;
+                }
+                System.out.print((char) ch);
+                buff.append((char) ch);
+            }
+            proc.waitFor();
+            assertEquals(0, proc.exitValue());
+            assertTrue(buff.toString(), buff.length() == 0);
+        }
+        Thread.sleep(100);
+        conn.close();
+    }
+
+}