CP-312082: [xapi] Only re-plug attached PIFs when applying LLDP

Apply the LLDP change to networkd only for PIFs that are currently
attached; an unplugged PIF has its DB value updated and picks up
the setting the next time it is brought up. This avoids bringing up
interfaces that were deliberately down as a side effect of a pure
LLDP configuration change.

PIF.set_lldp_mode re-plugs the target (self, or the bond master for
a bond member) only if it is currently_attached; pool.set_lldp_enabled
re-plugs only currently-attached standalone physical PIFs and bond
masters.

Signed-off-by: Changlei Li <changlei.li@citrix.com>

Author: changlei-li

ocaml/xapi/xapi_pif.ml

@@ -990,10 +990,13 @@ let set_lldp_mode ~__context ~self ~value ~force =
   assert_lldp_configurable ~__context ~self ;
   if force || Db.PIF.get_lldp_mode ~__context ~self <> value then (
     Db.PIF.set_lldp_mode ~__context ~self ~value ;
+    (* Re-apply to networkd only if the NIC is up; an unplugged PIF will pick
+       up the new setting the next time it is brought up. *)
     let to_plug = pif_to_plug_for_lldp ~__context ~self in
-    Helpers.call_api_functions ~__context (fun rpc session_id ->
-        Client.Client.PIF.plug ~rpc ~session_id ~self:to_plug
-    )
+    if Db.PIF.get_currently_attached ~__context ~self:to_plug then
+      Helpers.call_api_functions ~__context (fun rpc session_id ->
+          Client.Client.PIF.plug ~rpc ~session_id ~self:to_plug
+      )
   )
 
 let set_property ~__context ~self ~name ~value =

ocaml/xapi/xapi_pool.ml

@@ -3862,11 +3862,13 @@ let set_lldp_enabled ~__context ~self ~value ~force =
     Db.Pool.set_lldp_enabled ~__context ~self ~value ;
     (* LLDP runs on physical NICs. Standalone physical PIFs are plugged
        directly; bonded NICs are (re)configured by plugging the bond master.
-       Both apply the per-PIF PIF.lldp_mode against the new pool setting. *)
+       Only currently-attached PIFs are re-plugged; an unplugged PIF will pick
+       up the new pool setting the next time it is brought up. *)
     let pifs =
       Db.PIF.get_all_records ~__context
       |> List.filter (fun (_, r) ->
              r.API.pIF_managed
+             && r.API.pIF_currently_attached
              && (r.API.pIF_physical && r.API.pIF_bond_slave_of = Ref.null
                 || r.API.pIF_bond_master_of <> []
                 )