f2fs: missing REQ_META and REQ_PRIO when sync_meta_pages(META_FLUSH)

Doing sync_meta_pages with META_FLUSH when checkpoint, we overide rw
using WRITE_FLUSH_FUA. At this time, we also should set
REQ_META|REQ_PRIO.

Signed-off-by: Changman Lee <cm224.lee@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index e57bde0..bda889e 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -144,7 +144,7 @@
 	/* change META to META_FLUSH in the checkpoint procedure */
 	if (type >= META_FLUSH) {
 		io->fio.type = META_FLUSH;
-		io->fio.rw = WRITE_FLUSH_FUA;
+		io->fio.rw = WRITE_FLUSH_FUA | REQ_META | REQ_PRIO;
 	}
 	__submit_merged_bio(io);
 	mutex_unlock(&io->io_mutex);