--- a/fs/gfs2/quota.c
+++ b/fs/gfs2/quota.c
@@ -117,6 +117,7 @@ static void gfs2_qd_dispose(struct list_head *list)
 	while (!list_empty(list)) {
 		qd = list_first_entry(list, struct gfs2_quota_data, qd_lru);
 		sdp = qd->qd_gl->gl_name.ln_sbd;
+		mutex_lock(&sdp->sd_quota_sync_mutex);
 
 		list_del(&qd->qd_lru);
 
@@ -138,6 +139,7 @@ static void gfs2_qd_dispose(struct list_head *list)
 
 		/* Delete it from the common reclaim list */
 		call_rcu(&qd->qd_rcu, gfs2_qd_dealloc);
+		mutex_unlock(&sdp->sd_quota_sync_mutex);
 	}
 }