Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
        struct drbd_conf *mdev;
        int i;
 
+       if (tconn->net_conf && tconn->agreed_pro_version < 100 &&
+           tconn->cstate == C_WF_REPORT_PARAMS &&
+           new_conf->wire_protocol != tconn->net_conf->wire_protocol)
+               return ERR_NEED_APV_100;
+
        if (new_conf->two_primaries &&
            (new_conf->wire_protocol != DRBD_PROT_C))
                return ERR_NOT_PROTO_C;
 
        ERR_MINOR_CONFIGURED    = 160,
        ERR_MINOR_EXISTS        = 161,
        ERR_INVALID_REQUEST     = 162,
+       ERR_NEED_APV_100        = 163,
 
        /* insert new ones above this line */
        AFTER_LAST_ERR_CODE