From 82d1b7b4c79cef54f04e062f04b696544609a25b Mon Sep 17 00:00:00 2001
From: Dan Gudmundsson <dgud@erlang.org>
Date: Tue, 11 Oct 2016 15:19:10 +0200
Subject: mnesia: Fix double blocked tables which could cause a crash

Fast restarts could cause table to be blocked twice.
---
 lib/mnesia/src/mnesia_controller.erl | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

(limited to 'lib/mnesia/src/mnesia_controller.erl')

diff --git a/lib/mnesia/src/mnesia_controller.erl b/lib/mnesia/src/mnesia_controller.erl
index 4791e2e290..17b47c059e 100644
--- a/lib/mnesia/src/mnesia_controller.erl
+++ b/lib/mnesia/src/mnesia_controller.erl
@@ -1703,9 +1703,10 @@ add_active_replica(Tab, Node, Cs = #cstruct{}) ->
 
 block_table(Tab) ->
     Var = {Tab, where_to_commit},
-    Old = val(Var),
-    New = {blocked, Old},
-    set(Var, New). % where_to_commit
+    case is_tab_blocked(val(Var)) of
+        {true, _} -> ok;
+        {false, W2C} -> set(Var, mark_blocked_tab(true, W2C))
+    end.
 
 unblock_table(Tab) ->
     call({unblock_table, Tab}).
-- 
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