gfs2: drain ail under sd_log_flush_lock

When a withdraw is carried out, call gfs2_ail_drain() under the
sdp->sd_log_flush_lock.  This isn't strictly necessary but should be easier to
read, and more robust against possible future bugs.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

Author: Andreas Gruenbacher

fs/gfs2/util.c

@@ -123,9 +123,8 @@ static void do_withdraw(struct gfs2_sbd *sdp)
 		return;
 	}
 	clear_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
-	up_write(&sdp->sd_log_flush_lock);
-
 	gfs2_ail_drain(sdp); /* frees all transactions */
+	up_write(&sdp->sd_log_flush_lock);
 
 	wake_up(&sdp->sd_logd_waitq);
 	wake_up(&sdp->sd_quota_wait);