CA-424021: Add GC rule for PCI records

PCI records should be destroyed if the associated host reference is
invalid. This is needed to handle the case where a host is ejected from
a pool.

Signed-off-by: Rob Hoes <rob.hoes@citrix.com>

Author: robhoes

ocaml/xapi/db_gc_util.ml

@@ -234,6 +234,13 @@ let gc_VGPU_types ~__context =
         (String.concat "; " (List.map Ref.string_of (List.map fst garbage))) ;
       List.iter (fun (self, _) -> Db.VGPU_type.destroy ~__context ~self) garbage
 
+let gc_PCIs ~__context =
+  Db.PCI.get_all ~__context
+  |> List.iter (fun self ->
+      if not (valid_ref __context (Db.PCI.get_host ~__context ~self)) then
+        Db.PCI.destroy ~__context ~self
+  )
+
 let gc_Host_patches ~__context =
   gc_connector ~__context Db.Host_patch.get_all Db.Host_patch.get_record
     (fun x -> valid_ref __context x.host_patch_host)
@@ -627,6 +634,7 @@ let gc_subtask_list =
   ; ("VGPUs", gc_VGPUs)
   ; ("PGPUs", gc_PGPUs)
   ; ("VGPU_types", gc_VGPU_types)
+  ; ("PCIs", gc_PCIs)
   ; ("Host patches", gc_Host_patches)
   ; ("Host CPUs", gc_host_cpus)
   ; ("Host metrics", gc_host_metrics)