HPCC-32879 Fix issue with FileAttrLock being used on superfiles

For superfiles, use DXB_SuperFile for DfsXmlBranchKind argument
in the CFileAttrLock::init() call.

(If this is not done, superfile's attributes cannot be locked as
dali attempt to lock a non-existant path).

Signed-off-by: Shamser Ahmed <shamser.ahmed@lexisnexis.com>

dali/base/dadfs.cpp

@@ -2912,7 +2912,7 @@ class CDistributedFileBase : implements INTERFACE, public CInterface
         if (history)
             queryAttributes().removeTree(history);
     }
-    void lockFileAttrLock(CFileAttrLock & attrLock)
+    virtual void lockFileAttrLock(CFileAttrLock & attrLock)
     {
         if (!attrLock.init(logicalName, DXB_File, RTM_LOCK_WRITE, conn, defaultTimeout, "CDistributedFile::lockFileAttrLock"))
         {
@@ -6482,6 +6482,19 @@ class CDistributedSuperFile: public CDistributedFileBase<IDistributedSuperFile>
         return new cSubFileIterator(subfiles,supersub);
     }
 
+    virtual void lockFileAttrLock(CFileAttrLock & attrLock) override
+    {
+        if (!attrLock.init(logicalName, DXB_SuperFile, RTM_LOCK_WRITE, conn, defaultTimeout, "CDistributedFile::lockFileAttrLock"))
+        {
+            // In unlikely event File/Attr doesn't exist, must ensure created, commited and root connection is reloaded.
+            verifyex(attrLock.init(logicalName, DXB_SuperFile, RTM_LOCK_WRITE|RTM_CREATE_QUERY, conn, defaultTimeout, "CDistributedFile::lockFileAttrLock"));
+            attrLock.commit();
+            conn->commit();
+            conn->reload();
+            root.setown(conn->getRoot());
+        }
+    }
+
     void updateFileAttrs()
     {
         if (subfiles.ordinality()==0) {