drbd: move start io accounting before activity log transaction

The IO accounting of the drbd "queue depth" was misleading.
We only started IO accounting once we already wrote the activity log.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index b923d41..d72f2fe 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -1056,6 +1056,9 @@
 		req->private_bio = NULL;
 	}
 
+	/* Update disk stats */
+	_drbd_start_io_acct(mdev, req);
+
 	if (rw == WRITE && req->private_bio && req->i.size
 	&& !test_bit(AL_SUSPENDED, &mdev->flags)) {
 		if (!drbd_al_begin_io_fastpath(mdev, &req->i)) {
@@ -1095,9 +1098,6 @@
 		goto out;
 	}
 
-	/* Update disk stats */
-	_drbd_start_io_acct(mdev, req);
-
 	/* We fail READ/READA early, if we can not serve it.
 	 * We must do this before req is registered on any lists.
 	 * Otherwise, drbd_req_complete() will queue failed READ for retry. */