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authorHans Bolinder <[email protected]>2016-01-26 08:54:44 +0100
committerHans Bolinder <[email protected]>2016-01-26 08:54:44 +0100
commit6165f613a5b33aec2b9505a193fe7e309e2be7fd (patch)
tree791a680b9cf78709cdfe407b25180f6db63b11d0
parentfe2d78e98e01fb8a596bd6816e2f154a2d5cfdd0 (diff)
parent332d61900b466c3bb9f3892d272043e2ad3ffb90 (diff)
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Merge branch 'hb/stdlib/dets_fix/OTP-13260'
* hb/stdlib/dets_fix/OTP-13260: Fix a race bug affecting dets_SUITE:open_file/2
-rw-r--r--lib/stdlib/src/dets.erl10
-rw-r--r--lib/stdlib/test/dets_SUITE.erl53
2 files changed, 60 insertions, 3 deletions
diff --git a/lib/stdlib/src/dets.erl b/lib/stdlib/src/dets.erl
index 7036316242..6887bda67c 100644
--- a/lib/stdlib/src/dets.erl
+++ b/lib/stdlib/src/dets.erl
@@ -1291,7 +1291,15 @@ init(Parent, Server) ->
open_file_loop(#head{parent = Parent, server = Server}).
open_file_loop(Head) ->
- open_file_loop(Head, 0).
+ %% The Dets server pretends the file is open before
+ %% internal_open() has been called, which means that unless the
+ %% internal_open message is applied first, other processes can
+ %% find the pid by calling dets_server:get_pid() and do things
+ %% before Head has been initialized properly.
+ receive
+ ?DETS_CALL(From, {internal_open, _Ref, _Args}=Op) ->
+ do_apply_op(Op, From, Head, 0)
+ end.
open_file_loop(Head, N) when element(1, Head#head.update_mode) =:= error ->
open_file_loop2(Head, N);
diff --git a/lib/stdlib/test/dets_SUITE.erl b/lib/stdlib/test/dets_SUITE.erl
index e061e16e4c..b101054229 100644
--- a/lib/stdlib/test/dets_SUITE.erl
+++ b/lib/stdlib/test/dets_SUITE.erl
@@ -53,7 +53,8 @@
simultaneous_open/1, insert_new/1, repair_continuation/1,
otp_5487/1, otp_6206/1, otp_6359/1, otp_4738/1, otp_7146/1,
otp_8070/1, otp_8856/1, otp_8898/1, otp_8899/1, otp_8903/1,
- otp_8923/1, otp_9282/1, otp_11245/1, otp_11709/1, otp_13229/1]).
+ otp_8923/1, otp_9282/1, otp_11245/1, otp_11709/1, otp_13229/1,
+ otp_13260/1]).
-export([dets_dirty_loop/0]).
@@ -111,7 +112,7 @@ all() ->
insert_new, repair_continuation, otp_5487, otp_6206,
otp_6359, otp_4738, otp_7146, otp_8070, otp_8856, otp_8898,
otp_8899, otp_8903, otp_8923, otp_9282, otp_11245, otp_11709,
- otp_13229
+ otp_13229, otp_13260
].
groups() ->
@@ -4001,6 +4002,54 @@ otp_13229(_Config) ->
ok
end.
+otp_13260(doc) ->
+ ["OTP-13260. Race when opening a table."];
+otp_13260(Config) ->
+ [ok] = lists:usort([otp_13260_1(Config) || _ <- lists:seq(1, 3)]),
+ ok.
+
+otp_13260_1(Config) ->
+ Tab = otp_13260,
+ File = filename(Tab, Config),
+ N = 20,
+ P = self(),
+ Pids = [spawn_link(fun() -> counter(P, Tab, File) end) ||
+ _ <- lists:seq(1, N)],
+ Rs = rec(Pids),
+ true = lists:all(fun(R) -> is_integer(R) end, Rs),
+ wait_for_close(Tab).
+
+rec([]) ->
+ [];
+rec([Pid | Pids]) ->
+ receive {Pid, R} ->
+ [R | rec(Pids)]
+ end.
+
+%% One may have to run the test several times to trigger the bug.
+counter(P, Tab, File) ->
+ Key = key,
+ N = case catch dets:update_counter(Tab, Key, 1) of
+ {'EXIT', _} ->
+ {ok, Tab} = dets:open_file(Tab, [{file, File}]),
+ ok = dets:insert(Tab, {Key, 1}),
+ dets:update_counter(Tab, Key, 1);
+ N1 when is_integer(N1) ->
+ N1;
+ DetsBug ->
+ DetsBug
+ end,
+ P ! {self(), N}.
+
+wait_for_close(Tab) ->
+ case dets:info(Tab, owner) of
+ undefined ->
+ ok;
+ _ ->
+ timer:sleep(100),
+ wait_for_close(Tab)
+ end.
+
%%
%% Parts common to several test cases
%%