Perform frontend index writes in two phases

1 files changed, 18 insertions, 7 deletions

diff --git a/src/db.erl b/src/db.erl
index d2e0814..0541678 100644
--- a/src/db.erl
+++ b/src/db.erl
@@ -6,10 +6,11 @@
 
 %% API.
 -export([start_link/0, stop/0]).
--export([add/2, add_entryhash/2, add_index/2, set_treesize/1, size/0]).
+-export([add/2, add_entryhash/2, add_index_nosync/2, set_treesize/1, size/0]).
 -export([get_by_index/1, get_by_indices/3, get_by_leaf_hash/1]).
 -export([get_by_entry_hash/1, entry_for_leafhash/1, leafhash_for_index/1]).
 -export([leafhash_for_indices/2, indexsize/0]).
+-export([indexforhash_sync/2, index_sync/0]).
 %% gen_server callbacks.
 -export([init/1, handle_call/3, terminate/2, handle_cast/2, handle_info/2,
          code_change/3]).
@@ -48,9 +49,9 @@ add_entryhash(LeafHash, EntryHash) ->
     ok = perm:ensurefile(entryhash_root_path(), EntryHash, LeafHash),
     ok.
 
--spec add_index(binary(), non_neg_integer()) -> ok.
-add_index(LeafHash, Index) ->
-    call(?MODULE, {add_index, {LeafHash, Index}}).
+-spec add_index_nosync(binary(), non_neg_integer()) -> ok.
+add_index_nosync(LeafHash, Index) ->
+    call(?MODULE, {add_index_nosync, {LeafHash, Index}}).
 
 -spec set_treesize(non_neg_integer()) -> ok.
 set_treesize(Size) ->
@@ -177,8 +178,18 @@ get_by_indices_helper(Start, End) ->
 handle_call(stop, _From, State) ->
     {stop, normal, stopped, State};
 
-handle_call({add_index, {LeafHash, Index}}, _From, State) ->
-    ok = perm:ensurefile(indexforhash_root_path(),
-                         LeafHash, integer_to_binary(Index)),
+handle_call({add_index_nosync, {LeafHash, Index}}, _From, State) ->
+    ok = perm:ensurefile_nosync(indexforhash_root_path(),
+                                LeafHash, integer_to_binary(Index)),
     ok = index:add(index_path(), Index, LeafHash),
     {reply, ok, State}.
+
+indexforhash_sync(LeafHash, Index) ->
+    ok = perm:ensurefile(indexforhash_root_path(),
+                         LeafHash, integer_to_binary(Index)),
+    ok.
+
+index_sync() ->
+    Basepath = index_path(),
+    ok = util:fsync([Basepath, filename:dirname(Basepath)]),
+    ok.