drbd: explicitly submit meta data requests with REQ_NOIDLE

For some reason we have assumed NOIDLE was implied
by one of the other flags we set. It is not (anymore?).
Explicitly set REQ_NOIDLE for synchronous meta data updates,
or we can seriously starve random writes when using CFQ.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

drivers/block/drbd/drbd_actlog.c

@@ -150,7 +150,7 @@ static int _drbd_md_sync_page_io(struct drbd_device *device,
 
 	if ((rw & WRITE) && !test_bit(MD_NO_FUA, &device->flags))
 		rw |= REQ_FUA | REQ_FLUSH;
-	rw |= REQ_SYNC;
+	rw |= REQ_SYNC | REQ_NOIDLE;
 
 	bio = bio_alloc_drbd(GFP_NOIO);
 	bio->bi_bdev = bdev->md_bdev;