[#1900] node: Fix loosing the "maintenance" status

In previous implementation node lost maintenance status after successful
switching to it. For example, after some period of time node sent
bootstrap requests with the "online" state instead of "maintenance".

Make `startMaintenance` method to set maintenance status in the
`networkState`.

Signed-off-by: Leonard Lyubich <ctulhurider@gmail.com>

CHANGELOG.md

@@ -29,6 +29,7 @@ Changelog for NeoFS Node
 - Make it possible to use `shard.ContainerSize` in read-only mode (#1975)
 - Storage node now starts if at least one gRPC enpoint is available (#1893)
 - Missing object relatives in object removal session opened by NeoFS CLI (#1978)
+- Bringing a node back online during maintenance (#1900)
 
 ### Removed
 ### Updated

cmd/neofs-node/config.go

@@ -312,8 +312,9 @@ type internals struct {
 }
 
 // starts node's maintenance.
-func (c *internals) startMaintenance() {
+func (c *cfg) startMaintenance() {
 	c.isMaintenance.Store(true)
+	c.cfgNetmap.state.setControlNetmapStatus(control.NetmapStatus_MAINTENANCE)
 	c.log.Info("started local node's maintenance")
 }
 

cmd/neofs-node/netmap.go

@@ -84,7 +84,14 @@ func (s *networkState) setNodeInfo(ni *netmapSDK.NodeInfo) {
 		}
 	}
 
-	s.controlNetStatus.Store(ctrlNetSt)
+	s.setControlNetmapStatus(ctrlNetSt)
+}
+
+// sets the current node state to the given value. Subsequent cfg.bootstrap
+// calls will process this value to decide what status node should set in the
+// network.
+func (s *networkState) setControlNetmapStatus(st control.NetmapStatus) {
+	s.controlNetStatus.Store(st)
 }
 
 func (s *networkState) controlNetmapStatus() (res control.NetmapStatus) {