engines: posixaio: add support for DDIR_SYNCFS Flag the posixaio IO engine with FIO_ASYNCIO_SYNC_SYNCFS to indicate that it supports the syncfs operation, synchronously. Also change fio_posixaio_queue() to execute aio_fsync() only for sync operations that are not a syncfs, in which case, we directly call do_io_u_sync(). Signed-off-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Sitsofe Wheeler <sitsofe@yahoo.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>