merge_backup: Do not read logorder past what fetched indicates.

3 files changed, 29 insertions, 40 deletions

diff --git a/merge/src/merge_backup.erl b/merge/src/merge_backup.erl
index 5f4f3d5..768bd32 100644
--- a/merge/src/merge_backup.erl
+++ b/merge/src/merge_backup.erl
@@ -28,7 +28,7 @@ handle_cast(_Request, State) ->
     {noreply, State}.
 
 handle_info({timeout, _Timer, backup}, State) ->
-    backup(merge_util:readfile(fetched_path), State).
+    backup(merge_util:nfetched(), State).
 
 code_change(_OldVsn, State, _Extra) ->
     {ok, State}.
@@ -40,19 +40,9 @@ terminate(Reason, #state{timer = Timer}) ->
 
 %%%%%%%%%%%%%%%%%%%%
 
-backup(noentry, State) ->
+backup(Size, State) when Size < 0 ->
     {noreply, State#state{timer = erlang:start_timer(1000, self(), backup)}};
-backup({struct, Fetched}, State) ->
-    Index = proplists:get_value(<<"index">>, Fetched),
-    Hash = proplists:get_value(<<"hash">>, Fetched),
-    backup(Index, Hash, State).
-
-backup(-1, _, State) ->
-    {noreply, State#state{timer = erlang:start_timer(1000, self(), backup)}};
-backup(Index, Hash,
-        #state{node_name = NodeName, node_address = NodeAddress} = State) ->
-    ok = merge_util:verify_logorder_and_fetched_consistency(Index, Hash),
-    Size = index:indexsize(logorder),
+backup(Size, #state{node_name = NodeName, node_address = NodeAddress} = State) ->
     lager:debug("~p: logorder size ~B", [NodeName, Size]),
     ht:load_tree(Size - 1), % TODO: Make sure this is OK to do from multiple processes and that it's not "moving backwards".
     try
diff --git a/merge/src/merge_sth.erl b/merge/src/merge_sth.erl
index a34179d..3dffaca 100644
--- a/merge/src/merge_sth.erl
+++ b/merge/src/merge_sth.erl
@@ -58,7 +58,7 @@ make_sth(CurSize, State) ->
     %% entry with the size found in the 'fetched' file, sort the list
     %% (highest tree size first) and index it with backup quorum to
     %% get our new tree size.
-    Sizes = [fetched() | verified_sizes(MergeSecondaryNames)],
+    Sizes = [merge_util:nfetched() | verified_sizes(MergeSecondaryNames)],
     BackupQuorumSize = plopconfig:get_env(backup_quorum, 0),
     true = BackupQuorumSize =< length(MergeSecondaryNames),
     NewSize = lists:nth(BackupQuorumSize + 1, Sizes),
@@ -143,25 +143,6 @@ validate_tree_head(Treesize, Roothash) ->
                  root_mismatch
          end.
 
-fetched() ->
-    case read_fetched() of
-        {-1, _} ->
-            0;
-        {Index, Hash} ->
-            ok = merge_util:verify_logorder_and_fetched_consistency(Index, Hash),
-            Index + 1
-    end.
-
-read_fetched() ->            % FIXME: merge with backup implementation
-    case merge_util:readfile(fetched_path) of
-        noentry ->
-            {-1, <<>>};
-        {struct, PropList} ->
-            {proplists:get_value(<<"index">>, PropList),
-             proplists:get_value(<<"hash">>, PropList)}
-    end.
-
-
 read_sth_treesize() ->
     case plop:sth() of
         noentry ->
diff --git a/merge/src/merge_util.erl b/merge/src/merge_util.erl
index 4a4340d..1df1409 100644
--- a/merge/src/merge_util.erl
+++ b/merge/src/merge_util.erl
@@ -4,7 +4,7 @@
 -module(merge_util).
 -export([sendlog/4, sendentries/3]).
 -export([request/2, request/4]).
--export([readfile/1, verify_logorder_and_fetched_consistency/2]).
+-export([readfile/1, nfetched/0]).
 
 request(DebugTag, URL) ->
     request(DebugTag, URL, [], <<>>).
@@ -87,13 +87,31 @@ readfile(FileInConfig) ->
             noentry
     end.
 
-verify_logorder_and_fetched_consistency(Index, Hash) ->
-    HashString = binary_to_list(Hash),
+nfetched() ->
+    {Index, Hash} = read_fetched(),
+    case Index >= 0 of
+        true ->
+            ok = verify_logorder_entry(Index, binary_to_list(Hash));
+        false ->
+            ok
+    end,
+    Index + 1.
+
+read_fetched() ->
+    case merge_util:readfile(fetched_path) of
+        noentry ->
+            {-1, <<>>};
+        {struct, PropList} ->
+            {proplists:get_value(<<"index">>, PropList),
+             proplists:get_value(<<"hash">>, PropList)}
+    end.
+
+verify_logorder_entry(Index, HashAsString) ->
     case hex:bin_to_hexstr(index:get(logorder, Index)) of
-        HashString ->
+        HashAsString ->
             ok;
         Mismatch ->
-            lager:error("fetched file hash=~p doesn't match logorder[~B]=~p",
-                        [HashString, Index, Mismatch]),
-            fetched_mismatch
+            lager:error("hash in fetched file ~p doesn't match logorder[~B]=~p",
+                        [HashAsString, Index, Mismatch]),
+            mismatch
     end.