--- a/fs/gfs2/quota.c
+++ b/fs/gfs2/quota.c
@@ -1457,6 +1457,7 @@ void gfs2_quota_cleanup(struct gfs2_sbd *sdp)
 	struct gfs2_quota_data *qd;
 
 	spin_lock(&qd_lock);
+	mutex_lock(&sdp->sd_quota_sync_mutex);
 	while (!list_empty(head)) {
 		qd = list_last_entry(head, struct gfs2_quota_data, qd_list);
 
@@ -1480,6 +1481,7 @@ void gfs2_quota_cleanup(struct gfs2_sbd *sdp)
 
 		spin_lock(&qd_lock);
 	}
+	mutex_unlock(&sdp->sd_quota_sync_mutex);
 	spin_unlock(&qd_lock);
 
 	gfs2_assert_warn(sdp, !atomic_read(&sdp->sd_quota_count));