util: Introduce DirectoryCommit commit function to sync a directory

Author: eklitzke

src/util/system.cpp

@@ -1043,6 +1043,15 @@ bool FileCommit(FILE *file)
     return true;
 }
 
+void DirectoryCommit(const fs::path &dirname)
+{
+#ifndef WIN32
+    FILE* file = fsbridge::fopen(dirname, "r");
+    fsync(fileno(file));
+    fclose(file);
+#endif
+}
+
 bool TruncateFile(FILE *file, unsigned int length) {
 #if defined(WIN32)
     return _chsize(_fileno(file), length) == 0;

src/util/system.h

@@ -62,6 +62,13 @@ void PrintExceptionContinue(const std::exception *pex, const char* pszThread);
  * feature analogous to fsync().
  */
 bool FileCommit(FILE *file);
+
+/**
+ * Sync directory contents. This is required on some environments to ensure that
+ * newly created files are committed to disk.
+ */
+void DirectoryCommit(const fs::path &dirname);
+
 bool TruncateFile(FILE *file, unsigned int length);
 int RaiseFileDescriptorLimit(int nMinFD);
 void AllocateFileRange(FILE *file, unsigned int offset, unsigned int length);