nbd: Use default port if only host is specified

The URL method already takes care to apply the default port when none is
specfied. Directly specifying driver-specific options required the port
number until now. Allow leaving it out and apply the default.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

block/nbd.c

@@ -118,21 +118,18 @@ static int nbd_parse_uri(const char *filename, QDict *options)
         }
         qdict_put(options, "path", qstring_from_str(qp->p[0].value));
     } else {
-        /* nbd[+tcp]://host:port/export */
-        char *port_str;
-
+        /* nbd[+tcp]://host[:port]/export */
         if (!uri->server) {
             ret = -EINVAL;
             goto out;
         }
-        if (!uri->port) {
-            uri->port = NBD_DEFAULT_PORT;
-        }
 
-        port_str = g_strdup_printf("%d", uri->port);
         qdict_put(options, "host", qstring_from_str(uri->server));
-        qdict_put(options, "port", qstring_from_str(port_str));
-        g_free(port_str);
+        if (uri->port) {
+            char* port_str = g_strdup_printf("%d", uri->port);
+            qdict_put(options, "port", qstring_from_str(port_str));
+            g_free(port_str);
+        }
     }
 
 out:
@@ -223,6 +220,10 @@ static int nbd_config(BDRVNBDState *s, QDict *options)
         return -EINVAL;
     }
 
+    if (!qemu_opt_get(s->socket_opts, "port")) {
+        qemu_opt_set_number(s->socket_opts, "port", NBD_DEFAULT_PORT);
+    }
+
     s->export_name = g_strdup(qdict_get_try_str(options, "export"));
     if (s->export_name) {
         qdict_del(options, "export");