static int cifs_writepages_region(struct address_space *mapping,
				  struct writeback_control *wbc,
				  loff_t start, loff_t end, loff_t *_next)
static int cifs_writepages_region(struct address_space *mapping,
				  struct writeback_control *wbc,
				  unsigned long long *_start,
				  unsigned long long end)