drbd: Allow to disconnect if one volume is diskless

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

drivers/block/drbd/drbd_receiver.c

@@ -3447,7 +3447,7 @@ static int receive_req_conn_state(struct drbd_tconn *tconn, struct packet_info *
 	mask = convert_state(mask);
 	val = convert_state(val);
 
-	rv = conn_request_state(tconn, mask, val, CS_VERBOSE | CS_LOCAL_ONLY);
+	rv = conn_request_state(tconn, mask, val, CS_VERBOSE | CS_LOCAL_ONLY | CS_IGN_OUTD_FAIL);
 	conn_send_sr_reply(tconn, rv);
 
 	return 0;

drivers/block/drbd/drbd_state.c

@@ -1433,6 +1433,9 @@ conn_is_valid_transition(struct drbd_tconn *tconn, union drbd_state mask, union
 		os = mdev->state;
 		ns = sanitize_state(mdev, apply_mask_val(os, mask, val), NULL);
 
+		if (flags & CS_IGN_OUTD_FAIL && ns.disk == D_OUTDATED && os.disk < D_OUTDATED)
+			ns.disk = os.disk;
+
 		if (ns.i == os.i)
 			continue;
 
@@ -1475,6 +1478,9 @@ conn_set_state(struct drbd_tconn *tconn, union drbd_state mask, union drbd_state
 		ns = apply_mask_val(os, mask, val);
 		ns = sanitize_state(mdev, ns, NULL);
 
+		if (flags & CS_IGN_OUTD_FAIL && ns.disk == D_OUTDATED && os.disk < D_OUTDATED)
+			ns.disk = os.disk;
+
 		rv = __drbd_set_state(mdev, ns, flags, NULL);
 		if (rv < SS_SUCCESS)
 			BUG();

drivers/block/drbd/drbd_state.h

@@ -69,6 +69,7 @@ enum chg_state_flags {
 	CS_DC_DISK       = 1 << 8,
 	CS_DC_PDSK       = 1 << 9,
 	CS_DC_MASK       = CS_DC_ROLE + CS_DC_PEER + CS_DC_CONN + CS_DC_DISK + CS_DC_PDSK,
+	CS_IGN_OUTD_FAIL = 1 << 10,
 };
 
 extern enum drbd_state_rv drbd_change_state(struct drbd_conf *mdev,