diff --git a/hadoop-ozone/client/src/test/java/org/apache/hadoop/ozone/client/MockDatanodeStorage.java b/hadoop-ozone/client/src/test/java/org/apache/hadoop/ozone/client/MockDatanodeStorage.java
index 393e8cdb3112..caa3996a09ff 100644
--- a/hadoop-ozone/client/src/test/java/org/apache/hadoop/ozone/client/MockDatanodeStorage.java
+++ b/hadoop-ozone/client/src/test/java/org/apache/hadoop/ozone/client/MockDatanodeStorage.java
@@ -162,10 +162,10 @@ public void writeChunk(
     if (data.containsKey(blockKey)) {
       block = data.get(blockKey);
       assert block.size() == chunkInfo.getOffset();
-      data.put(blockKey, block.concat(bytes));
+      data.put(blockKey, block.concat(ByteString.copyFrom(bytes.asReadOnlyByteBuffer())));
     } else {
       assert chunkInfo.getOffset() == 0;
-      data.put(blockKey, bytes);
+      data.put(blockKey, ByteString.copyFrom(bytes.asReadOnlyByteBuffer()));
     }
 
     fullBlockData