Index: lucene/core/src/java/org/apache/lucene/index/SegmentReader.java
===================================================================
--- lucene/core/src/java/org/apache/lucene/index/SegmentReader.java	(revision 1481937)
+++ lucene/core/src/java/org/apache/lucene/index/SegmentReader.java	(working copy)
@@ -58,7 +58,7 @@
     try {
       if (si.hasDeletions()) {
         // NOTE: the bitvector is stored using the regular directory, not cfs
-        liveDocs = si.info.getCodec().liveDocsFormat().readLiveDocs(directory(), si, new IOContext(IOContext.READ, true));
+        liveDocs = si.info.getCodec().liveDocsFormat().readLiveDocs(directory(), si, IOContext.READONCE);
       } else {
         assert si.getDelCount() == 0;
         liveDocs = null;
Index: lucene/core/src/java/org/apache/lucene/index/BufferedDeletesStream.java
===================================================================
--- lucene/core/src/java/org/apache/lucene/index/BufferedDeletesStream.java	(revision 1481937)
+++ lucene/core/src/java/org/apache/lucene/index/BufferedDeletesStream.java	(working copy)
@@ -206,7 +206,7 @@
         // Lock order: IW -> BD -> RP
         assert readerPool.infoIsLive(info);
         final ReadersAndLiveDocs rld = readerPool.get(info, true);
-        final SegmentReader reader = rld.getReader(IOContext.READ);
+        final SegmentReader reader = rld.getReader(IOContext.READONCE);
         int delCount = 0;
         final boolean segAllDeletes;
         try {
@@ -259,7 +259,7 @@
           // Lock order: IW -> BD -> RP
           assert readerPool.infoIsLive(info);
           final ReadersAndLiveDocs rld = readerPool.get(info, true);
-          final SegmentReader reader = rld.getReader(IOContext.READ);
+          final SegmentReader reader = rld.getReader(IOContext.READONCE);
           int delCount = 0;
           final boolean segAllDeletes;
           try {
Index: lucene/core/src/java/org/apache/lucene/index/CheckIndex.java
===================================================================
--- lucene/core/src/java/org/apache/lucene/index/CheckIndex.java	(revision 1481937)
+++ lucene/core/src/java/org/apache/lucene/index/CheckIndex.java	(working copy)
@@ -412,7 +412,7 @@
     // note: we only read the format byte (required preamble) here!
     IndexInput input = null;
     try {
-      input = dir.openInput(segmentsFileName, IOContext.DEFAULT);
+      input = dir.openInput(segmentsFileName, IOContext.READONCE);
     } catch (Throwable t) {
       msg(infoStream, "ERROR: could not open segments file in directory");
       if (infoStream != null)
Index: lucene/core/src/java/org/apache/lucene/index/IndexWriter.java
===================================================================
--- lucene/core/src/java/org/apache/lucene/index/IndexWriter.java	(revision 1481937)
+++ lucene/core/src/java/org/apache/lucene/index/IndexWriter.java	(working copy)
@@ -3811,7 +3811,7 @@
       final IndexReaderWarmer mergedSegmentWarmer = config.getMergedSegmentWarmer();
       if (poolReaders && mergedSegmentWarmer != null && merge.info.info.getDocCount() != 0) {
         final ReadersAndLiveDocs rld = readerPool.get(merge.info, true);
-        final SegmentReader sr = rld.getReader(IOContext.READ);
+        final SegmentReader sr = rld.getReader(IOContext.READONCE);
         try {
           mergedSegmentWarmer.warm(sr);
         } finally {
Index: lucene/test-framework/src/java/org/apache/lucene/index/BasePostingsFormatTestCase.java
===================================================================
--- lucene/test-framework/src/java/org/apache/lucene/index/BasePostingsFormatTestCase.java	(revision 1481937)
+++ lucene/test-framework/src/java/org/apache/lucene/index/BasePostingsFormatTestCase.java	(working copy)
@@ -567,7 +567,7 @@
 
     currentFieldInfos = newFieldInfos;
 
-    SegmentReadState readState = new SegmentReadState(dir, segmentInfo, newFieldInfos, IOContext.DEFAULT, 1);
+    SegmentReadState readState = new SegmentReadState(dir, segmentInfo, newFieldInfos, IOContext.READ, 1);
 
     return codec.postingsFormat().fieldsProducer(readState);
   }