use mnesia:system_config(use_dir)

2 files changed, 11 insertions, 3 deletions

diff --git a/src/rabbit_mnesia.erl b/src/rabbit_mnesia.erl
index f94db8af48..9d1fe42301 100644
--- a/src/rabbit_mnesia.erl
+++ b/src/rabbit_mnesia.erl
@@ -602,7 +602,7 @@ is_disc_node() ->
     %% This is pretty ugly but we can't start Mnesia and ask it (will hang),
     %% we can't look at the config file (may not include us even if we're a
     %% disc node).
-    filelib:is_regular(filename:join(dir(), "rabbit_durable_exchange.DCD")).
+    mnesia:system_info(use_dir).
 
 should_be_disc_node(ClusterNodes) ->
     ClusterNodes == [] orelse lists:member(node(), ClusterNodes).
diff --git a/src/rabbit_upgrade.erl b/src/rabbit_upgrade.erl
index e6b52c61e3..a6d04f7eaf 100644
--- a/src/rabbit_upgrade.erl
+++ b/src/rabbit_upgrade.erl
@@ -144,7 +144,7 @@ upgrade_mode(AllNodes) ->
     case nodes_running(AllNodes) of
         [] ->
             AfterUs = rabbit_mnesia:read_previously_running_nodes(),
-            case {rabbit_mnesia:is_disc_node(), AfterUs} of
+            case {is_disc_node(), AfterUs} of
                 {true, []}  ->
                     primary;
                 {true, _}  ->
@@ -212,7 +212,7 @@ force_tables() ->
 
 secondary_upgrade(AllNodes) ->
     %% must do this before we wipe out schema
-    IsDiscNode = rabbit_mnesia:is_disc_node(),
+    IsDiscNode = is_disc_node(),
     rabbit_misc:ensure_ok(mnesia:delete_schema([node()]),
                           cannot_delete_schema),
     %% Note that we cluster with all nodes, rather than all disc nodes
@@ -276,6 +276,14 @@ lock_filename() -> lock_filename(dir()).
 lock_filename(Dir) -> filename:join(Dir, ?LOCK_FILENAME).
 backup_dir() -> dir() ++ "-upgrade-backup".
 
+is_disc_node() ->
+    %% This is pretty ugly but we can't start Mnesia and ask it (will
+    %% hang), we can't look at the config file (may not include us
+    %% even if we're a disc node).  We also can't use
+    %% rabbit_mnesia:is_disc_node/0 because that will give false
+    %% postivies on Rabbit up to 2.5.1.
+    filelib:is_regular(filename:join(dir(), "rabbit_durable_exchange.DCD")).
+
 %% NB: we cannot use rabbit_log here since it may not have been
 %% started yet
 info(Msg, Args) -> error_logger:info_msg(Msg, Args).