FileStore count fields need to be atomically accessed

shows up as random failures in the TestMVStore.testFastDelete test case

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

@@ -10,7 +10,7 @@ import java.nio.ByteBuffer;
 import java.nio.channels.FileChannel;
 import java.nio.channels.FileLock;
 import java.nio.channels.OverlappingFileLockException;
-
+import java.util.concurrent.atomic.AtomicLong;
 import org.h2.mvstore.cache.FilePathCache;
 import org.h2.store.fs.FilePath;
 import org.h2.store.fs.FilePathDisk;
@@ -27,22 +27,22 @@ public class FileStore {
     /**
      * The number of read operations.
      */
-    protected long readCount;
+    protected final AtomicLong readCount = new AtomicLong(0);
 
     /**
      * The number of read bytes.
      */
-    protected long readBytes;
+    protected final AtomicLong readBytes = new AtomicLong(0);
 
     /**
      * The number of write operations.
      */
-    protected long writeCount;
+    protected final AtomicLong writeCount = new AtomicLong(0);
 
     /**
      * The number of written bytes.
      */
-    protected long writeBytes;
+    protected final AtomicLong writeBytes = new AtomicLong(0);
 
     /**
      * The free spaces between the chunks. The first block to use is block 2
@@ -96,8 +96,8 @@ public class FileStore {
     public ByteBuffer readFully(long pos, int len) {
         ByteBuffer dst = ByteBuffer.allocate(len);
         DataUtils.readFully(file, pos, dst);
-        readCount++;
-        readBytes += len;
+        readCount.incrementAndGet();
+        readBytes.addAndGet(len);
         return dst;
     }
 
@@ -111,8 +111,8 @@ public class FileStore {
         int len = src.remaining();
         fileSize = Math.max(fileSize, pos + len);
         DataUtils.writeFully(file, pos, src);
-        writeCount++;
-        writeBytes += len;
+        writeCount.incrementAndGet();
+        writeBytes.addAndGet(len);
     }
 
     /**
@@ -231,7 +231,7 @@ public class FileStore {
      */
     public void truncate(long size) {
         try {
-            writeCount++;
+            writeCount.incrementAndGet();
             file.truncate(size);
             fileSize = Math.min(fileSize, size);
         } catch (IOException e) {
@@ -273,7 +273,7 @@ public class FileStore {
      * @return the number of write operations
      */
     public long getWriteCount() {
-        return writeCount;
+        return writeCount.get();
     }
 
     /**
@@ -282,7 +282,7 @@ public class FileStore {
      * @return the number of write operations
      */
     public long getWriteBytes() {
-        return writeBytes;
+        return writeBytes.get();
     }
 
     /**
@@ -292,7 +292,7 @@ public class FileStore {
      * @return the number of read operations
      */
     public long getReadCount() {
-        return readCount;
+        return readCount.get();
     }
 
     /**
@@ -301,7 +301,7 @@ public class FileStore {
      * @return the number of write operations
      */
     public long getReadBytes() {
-        return readBytes;
+        return readBytes.get();
     }
 
     public boolean isReadOnly() {

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

@@ -1292,7 +1292,7 @@ public final class MVStore {
     private Set<Integer> collectReferencedChunks() {
         long testVersion = lastChunk.version;
         DataUtils.checkArgument(testVersion > 0, "Collect references on version 0");
-        long readCount = getFileStore().readCount;
+        long readCount = getFileStore().readCount.get();
         Set<Integer> referenced = New.hashSet();
         for (Cursor<String, String> c = meta.cursor("root."); c.hasNext();) {
             String key = c.next();
@@ -1308,7 +1308,7 @@ public final class MVStore {
         }
         long pos = lastChunk.metaRootPos;
         collectReferencedChunks(referenced, 0, pos, 0);
-        readCount = fileStore.readCount - readCount;
+        readCount = fileStore.readCount.get() - readCount;
         return referenced;
     }
 

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

@@ -37,8 +37,8 @@ public class OffHeapStore extends FileStore {
                     DataUtils.ERROR_READING_FAILED,
                     "Could not read from position {0}", pos);
         }
-        readCount++;
-        readBytes += len;
+        readCount.incrementAndGet();
+        readBytes.addAndGet(len);
         ByteBuffer buff = memEntry.getValue();
         ByteBuffer read = buff.duplicate();
         int offset = (int) (pos - memEntry.getKey());
@@ -80,8 +80,8 @@ public class OffHeapStore extends FileStore {
                         "Could not write to position {0}; " +
                         "partial overwrite is not supported", pos);
             }
-            writeCount++;
-            writeBytes += length;
+            writeCount.incrementAndGet();
+            writeBytes.addAndGet(length);
             buff.rewind();
             buff.put(src);
             return;
@@ -97,8 +97,8 @@ public class OffHeapStore extends FileStore {
 
     private void writeNewEntry(long pos, ByteBuffer src) {
         int length = src.remaining();
-        writeCount++;
-        writeBytes += length;
+        writeCount.incrementAndGet();
+        writeBytes.addAndGet(length);
         ByteBuffer buff = ByteBuffer.allocateDirect(length);
         buff.put(src);
         buff.rewind();
@@ -107,7 +107,7 @@ public class OffHeapStore extends FileStore {
 
     @Override
     public void truncate(long size) {
-        writeCount++;
+        writeCount.incrementAndGet();
         if (size == 0) {
             fileSize = 0;
             memory.clear();