diff --git a/src/main.h b/src/main.h
index 5ac5547a3..331b16b50 100644
--- a/src/main.h
+++ b/src/main.h
@@ -956,13 +956,7 @@ public:
         // Flush stdio buffers and commit to disk before returning
         fflush(fileout);
         if (!IsInitialBlockDownload() || (nBestHeight+1) % 500 == 0)
-        {
-#ifdef WIN32
-            _commit(_fileno(fileout));
-#else
-            fsync(fileno(fileout));
-#endif
-        }
+            FileCommit(fileout);
 
         return true;
     }
diff --git a/src/util.cpp b/src/util.cpp
index 823d00a4e..82c16feda 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -910,6 +910,27 @@ void CreatePidFile(const boost::filesystem::path &path, pid_t pid)
     }
 }
 
+bool RenameOver(boost::filesystem::path src, boost::filesystem::path dest)
+{
+#ifdef WIN32
+    return MoveFileEx(src.string().c_str(), dest.string().c_str(),
+                      MOVEFILE_REPLACE_EXISTING);
+#else
+    int rc = std::rename(src.string().c_str(), dest.string().c_str());
+    return (rc == 0);
+#endif /* WIN32 */
+}
+
+void FileCommit(FILE *fileout)
+{
+    fflush(fileout);                // harmless if redundantly called
+#ifdef WIN32
+    _commit(_fileno(fileout));
+#else
+    fsync(fileno(fileout));
+#endif
+}
+
 int GetFilesize(FILE* file)
 {
     int nSavePos = ftell(file);
diff --git a/src/util.h b/src/util.h
index 8e65fa786..f7bdaf533 100644
--- a/src/util.h
+++ b/src/util.h
@@ -152,7 +152,9 @@ std::string EncodeBase64(const std::string& str);
 void ParseParameters(int argc, const char*const argv[]);
 bool WildcardMatch(const char* psz, const char* mask);
 bool WildcardMatch(const std::string& str, const std::string& mask);
+void FileCommit(FILE *fileout);
 int GetFilesize(FILE* file);
+bool RenameOver(boost::filesystem::path src, boost::filesystem::path dest);
 boost::filesystem::path GetDefaultDataDir();
 const boost::filesystem::path &GetDataDir(bool fNetSpecific = true);
 boost::filesystem::path GetConfigFile();