Merge pull request #1657 from h2database/panic-bkg

Failure to stop background thread

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

@@ -186,23 +186,22 @@ public class FileStore {
      * Close this store.
      */
     public void close() {
-        if(file != null) {
         try {
+            if(file != null && file.isOpen()) {
                 if (fileLock != null) {
                     fileLock.release();
-                    fileLock = null;
                 }
                 file.close();
-                freeSpace.clear();
+            }
         } catch (Exception e) {
             throw DataUtils.newIllegalStateException(
                     DataUtils.ERROR_WRITING_FAILED,
                     "Closing failed for file {0}", fileName, e);
         } finally {
+            fileLock = null;
             file = null;
         }
     }
-    }
 
     /**
      * Flush all changes.

h2/src/main/org/h2/mvstore/MVStore.java

@@ -2845,10 +2845,10 @@ public class MVStore implements AutoCloseable {
         // which should not happen with non-weak flavour of CAS operation,
         // but I've seen it, so just to be safe...
         BackgroundWriterThread t;
-        while ((t = backgroundWriterThread.get()) != null &&
-                // if called from within the thread itself - can not join
-                t != Thread.currentThread()) {
+        while ((t = backgroundWriterThread.get()) != null) {
             if (backgroundWriterThread.compareAndSet(t, null)) {
+                // if called from within the thread itself - can not join
+                if (t != Thread.currentThread()) {
                     synchronized (t.sync) {
                         t.sync.notifyAll();
                     }
@@ -2860,6 +2860,7 @@ public class MVStore implements AutoCloseable {
                             // ignore
                         }
                     }
+                }
                 break;
             }
         }