diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 1fd655ac806a..7c00dd530bd1 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -1137,6 +1137,21 @@ static int send_renew_caps(struct ceph_mds_client *mdsc,
 	return 0;
 }
 
+static int send_flushmsg_ack(struct ceph_mds_client *mdsc,
+			     struct ceph_mds_session *session, u64 seq)
+{
+	struct ceph_msg *msg;
+
+	dout("send_flushmsg_ack to mds%d (%s)s seq %lld\n",
+	     session->s_mds, session_state_name(session->s_state), seq);
+	msg = create_session_msg(CEPH_SESSION_FLUSHMSG_ACK, seq);
+	if (!msg)
+		return -ENOMEM;
+	ceph_con_send(&session->s_con, msg);
+	return 0;
+}
+
+
 /*
  * Note new cap ttl, and any transition from stale -> not stale (fresh?).
  *
@@ -2396,6 +2411,10 @@ static void handle_session(struct ceph_mds_session *session,
 		trim_caps(mdsc, session, le32_to_cpu(h->max_caps));
 		break;
 
+	case CEPH_SESSION_FLUSHMSG:
+		send_flushmsg_ack(mdsc, session, seq);
+		break;
+
 	default:
 		pr_err("mdsc_handle_session bad op %d mds%d\n", op, mds);
 		WARN_ON(1);
diff --git a/fs/ceph/strings.c b/fs/ceph/strings.c
index 89fa4a940a0f..4440f447fd3f 100644
--- a/fs/ceph/strings.c
+++ b/fs/ceph/strings.c
@@ -41,6 +41,8 @@ const char *ceph_session_op_name(int op)
 	case CEPH_SESSION_RENEWCAPS: return "renewcaps";
 	case CEPH_SESSION_STALE: return "stale";
 	case CEPH_SESSION_RECALL_STATE: return "recall_state";
+	case CEPH_SESSION_FLUSHMSG: return "flushmsg";
+	case CEPH_SESSION_FLUSHMSG_ACK: return "flushmsg_ack";
 	}
 	return "???";
 }
diff --git a/include/linux/ceph/ceph_fs.h b/include/linux/ceph/ceph_fs.h
index 2ad7b860f062..26bb587deb78 100644
--- a/include/linux/ceph/ceph_fs.h
+++ b/include/linux/ceph/ceph_fs.h
@@ -282,6 +282,8 @@ enum {
 	CEPH_SESSION_RENEWCAPS,
 	CEPH_SESSION_STALE,
 	CEPH_SESSION_RECALL_STATE,
+	CEPH_SESSION_FLUSHMSG,
+	CEPH_SESSION_FLUSHMSG_ACK,
 };
 
 extern const char *ceph_session_op_name(int op);