Added some small modifications

src/backing.c

@@ -68,3 +68,18 @@ Status GetBackingDiskPath(const char* backing_identifier, char** _backing_path)
 
 	return status;
 }
+
+Status DoesBackingExist(const char* backing_identifier, bool* _result) {
+	// Get the backing path
+	char* backing_path = NULL;
+	Status status = GetBackingDiskPath(backing_identifier, &backing_path);
+	if (status != SUCCESS)
+		return status;
+
+	// Check if the backing exists and is a regular file
+	struct stat st;
+	*_result = stat(backing_path, &st) == 0 && S_ISREG(st.st_mode);
+	free(backing_path);
+
+	return SUCCESS;
+}