Address remaining issues in PR

* Remove lock defs file; it was moved to riak_kv_vnode.hrl since all these locks are KV-specific * The optional call to handoff_started/2 allows vnodes one last chance to abort the handoff process. the function is passed the source vnode's partition number and node name (this node) because the callback does not have access to the full vnode state at this time. In addition the worker pid is passed so the vnode may use that information in its decision to cancel the handoff or not (e.g. get a lock on behalf of the process) * Move code that calls handooff_started/2 into separate function and put the call inside the try/catch.
doubaokun · Dec 20, 2013 · ae6b3f8 · ae6b3f8
1 parent 23f9464
commit ae6b3f8
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diff --git a/include/riak_core_locks.hrl b/include/riak_core_locks.hrl
diff --git a/src/riak_core_handoff_sender.erl b/src/riak_core_handoff_sender.erl
@@ -93,27 +93,10 @@ start_fold(TargetNode, Module, {Type, Opts}, ParentPid, SslOpts) ->
     SrcPartition = get_src_partition(Opts),
     TargetPartition = get_target_partition(Opts),
 
-    %% Consult handoff module for optional implemenation of handoff_started/2
-    case lists:member({handoff_started, 2}, Module:module_info(exports)) of
-        true ->
-            Source = {SrcPartition, SrcNode},
-            WorkerPid = self(),
-            case Module:handoff_started(Source, WorkerPid) of
-                true ->
-                    ok;
-                max_concurrency ->
-                    %% Handoff of that partition is busy or can't proceed. Stopping with
-                    %% max_concurrency will cause this partition to be retried again later.
-                    exit({shutdown, max_concurrency});
-                Error ->
-                    exit({shutdown, Error})
-            end;
-        false ->
-            %% optional callback not implemented, so we carry on.
-            ok
-    end,
-
     try
+        %% Give workers one more chance to abort or get a lock or whatever.
+        maybe_call_handoff_started(Module, SrcPartition, SrcNode),
+
          Filter = get_filter(Opts),
          [_Name,Host] = string:tokens(atom_to_list(TargetNode), "@"),
          {ok, Port} = get_handoff_port(TargetNode),
@@ -590,3 +573,29 @@ remote_supports_batching(Node) ->
             false
     end.
 
+%% @private
+%% @doc The optional call to handoff_started/2 allows vnodes one last chance to abort
+%% the handoff process. the function is passed the source vnode's partition number
+%% and node name (this node) because the callback does not have access to the full vnode
+%% state at this time. In addition the worker pid is passed so the vnode may use that
+%% information in its decision to cancel the handoff or not (e.g. get a lock on behalf
+%% of the process.
+maybe_call_handoff_started(Module, SrcPartition, SrcNode) ->
+    case lists:member({handoff_started, 2}, Module:module_info(exports)) of
+        true ->
+            Source = {SrcPartition, SrcNode},
+            WorkerPid = self(),
+            case Module:handoff_started(Source, WorkerPid) of
+                true ->
+                    ok;
+                max_concurrency ->
+                    %% Handoff of that partition is busy or can't proceed. Stopping with
+                    %% max_concurrency will cause this partition to be retried again later.
+                    exit({shutdown, max_concurrency});
+                Error ->
+                    exit({shutdown, Error})
+            end;
+        false ->
+            %% optional callback not implemented, so we carry on.
+            ok
+    end.