int exfat_build_file_dentry_set(struct exfat *exfat, const char *name,
unsigned short attr, struct exfat_dentry **dentry_set,
int *dentry_count);
+int exfat_find_free_cluster(struct exfat *exfat, clus_t start, clus_t *new_clu);
int exfat_add_dentry_set(struct exfat *exfat, struct exfat_dentry_loc *loc,
struct exfat_dentry *dset, int dcount,
bool need_next_loc);