fixup! CP-52226 - oxenstored: Implement partial directory call for do…

…m0 with per-connection cache

oxenstored/connection.ml

@@ -103,6 +103,9 @@ and t = {
     xb: Xenbus.Xb.t
   ; dom: Domain.t option
   ; transactions: (int, Transaction.t) Hashtbl.t
+  ; directory_cache_gen_count: int64 ref
+        (* Used to provide connection-unique generation counts in case a cache entry
+           was evicted and TODO *)
   ; directory_cache:
       (Store.Path.t, Store.Node.t * int64 * string * float) Hashtbl.t option
         (* Used for partial_directory calls, maps
@@ -239,6 +242,10 @@ let create xbcon dom =
       xb= xbcon
     ; dom
     ; transactions= Hashtbl.create 5
+    ; directory_cache_gen_count=
+        ref 1L
+        (* Start the generation count with 1, since 0 is a special
+           NULL value in CXenstored *)
     ; directory_cache
     ; next_tid= initial_next_tid
     ; watches= Hashtbl.create 8

oxenstored/process.ml

@@ -362,6 +362,7 @@ let do_directory_part con t _domains _cons data =
 
   let generation, children =
     Transaction.ls_partial t (Connection.get_perm con) path directory_cache
+      con.Connection.directory_cache_gen_count
   in
 
   let generation_s = Printf.sprintf "%Ld\000" generation in

oxenstored/transaction.ml

@@ -222,7 +222,7 @@ let ls t perm path =
   let _node, r = Store.ls t.store perm path in
   set_read_lowpath t path ; r
 
-let ls_partial t perm path directory_cache =
+let ls_partial t perm path directory_cache max_gen_count =
   let configurable_cache_size = 8 in
   let check_hashtable_bounds ht =
     if Hashtbl.length ht >= configurable_cache_size then
@@ -239,6 +239,12 @@ let ls_partial t perm path directory_cache =
       Hashtbl.remove ht (Option.get key)
   in
 
+  let inc_gen_count gen_cnt =
+    let r = !gen_cnt in
+    gen_cnt := Int64.add !gen_cnt 1L ;
+    r
+  in
+
   (* Return the cached buffer if the node hasn't changed; otherwise
      create or refresh the cache *)
   let ( let* ) = Option.bind in
@@ -268,17 +274,7 @@ let ls_partial t perm path directory_cache =
           else
             ""
         in
-        (* We need to increment the generation count if the cache existed
-           but needed to be refreshed *)
-        let generation_count =
-          match cache_opt with
-          | Some (_, generation_count, _, _) ->
-              Int64.add generation_count 1L
-          | None ->
-              1L
-          (* Start the generation count with 1, since 0 is a special
-             NULL value in CXenstored *)
-        in
+        let generation_count = inc_gen_count max_gen_count in
         (* Check the bounds, evict something from the hashtable
            to keep its size bounded *)
         check_hashtable_bounds directory_cache ;