Index: lucene/src/java/org/apache/lucene/index/SegmentReader.java
===================================================================
--- lucene/src/java/org/apache/lucene/index/SegmentReader.java	(revision 1180081)
+++ lucene/src/java/org/apache/lucene/index/SegmentReader.java	(working copy)
@@ -50,7 +50,7 @@
   CloseableThreadLocal<FieldsReader> fieldsReaderLocal = new FieldsReaderLocal();
   CloseableThreadLocal<TermVectorsReader> termVectorsLocal = new CloseableThreadLocal<TermVectorsReader>();
 
-  volatile BitVector liveDocs;
+  BitVector liveDocs;
   AtomicInteger liveDocsRef = null;
   private boolean liveDocsDirty = false;
   private boolean normsDirty = false;
@@ -136,7 +136,7 @@
 
   @Override
   public Bits getLiveDocs() {
-    ensureOpen();
+    // Don't call ensureOpen() here (it could affect performance), and this implementation will still work fine after close anyway
     return liveDocs;
   }