HDFS-10265. OEV tool fails to read edit xml file if OP_UPDATE_BLOCKS has no BLOCK tag (Wan Chang via cmccabe)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSEditLogOp.java

@@ -1096,7 +1096,8 @@ public abstract class FSEditLogOp {
     
     @Override void fromXml(Stanza st) throws InvalidXmlException {
       this.path = st.getValue("PATH");
-      List<Stanza> blocks = st.getChildren("BLOCK");
+      List<Stanza> blocks = st.hasChildren("BLOCK") ?
+          st.getChildren("BLOCK") : new ArrayList<Stanza>();
       this.blocks = new Block[blocks.size()];
       for (int i = 0; i < blocks.size(); i++) {
         this.blocks[i] = FSEditLogOp.blockFromXml(blocks.get(i));

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/DFSTestUtil.java

@@ -1272,6 +1272,18 @@ public class DFSTestUtil {
     // OP_APPEND 47
     FSDataOutputStream s2 = filesystem.append(pathFileCreate, 4096, null);
     s2.close();
+
+    // OP_UPDATE_BLOCKS 25
+    final String updateBlockFile = "/update_blocks";
+    FSDataOutputStream fout = filesystem.create(new Path(updateBlockFile), true, 4096, (short)1, 4096L);
+    fout.write(1);
+    fout.hflush();
+    long fileId = ((DFSOutputStream)fout.getWrappedStream()).getFileId();
+    DFSClient dfsclient = DFSClientAdapter.getDFSClient(filesystem);
+    LocatedBlocks blocks = dfsclient.getNamenode().getBlockLocations(updateBlockFile, 0, Integer.MAX_VALUE);
+    dfsclient.getNamenode().abandonBlock(blocks.get(0).getBlock(), fileId, updateBlockFile, dfsclient.clientName);
+    fout.close();
+
     // OP_SET_STORAGE_POLICY 45
     filesystem.setStoragePolicy(pathFileCreate,
         HdfsConstants.HOT_STORAGE_POLICY_NAME);