Make it call .write_pagemap once and decide whether or not to
call .write_pages based on the flags caluculated in one place
as well.
Acked-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>