static int exfat_search_empty_slot(struct super_block *sb,
		struct exfat_hint_femp *hint_femp, struct exfat_chain *p_dir,
		int num_entries)
static int exfat_search_empty_slot(struct super_block *sb,
		struct exfat_hint_femp *hint_femp, struct exfat_chain *p_dir,
		int num_entries, struct exfat_entry_set_cache *es)