exfat_alloc_cluster
ret = exfat_alloc_cluster(inode, 1, clu, IS_DIRSYNC(inode));
int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc,
ret = exfat_alloc_cluster(inode, new_num_clusters - num_clusters,
ret = exfat_alloc_cluster(inode, num_to_be_allocated, &new_clu,
ret = exfat_alloc_cluster(inode, 1, &clu, IS_DIRSYNC(inode));