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authorHans Bolinder <[email protected]>2014-10-23 09:02:28 +0200
committerHans Bolinder <[email protected]>2014-10-23 09:02:28 +0200
commit527ae7b5030ba7339eba5ba4089888c8f90e2879 (patch)
treeffd9350604b0f02cee5ea8de8e77c50dd5966597 /lib/stdlib/src
parentaeeda10c7ada4f81add3cb9c0b8205cc15168675 (diff)
parentff3fae223431a9cb0d2a2852a07f9447960c92ed (diff)
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Merge branch 'maint'
* maint: Fix rare race condition in Dets
Diffstat (limited to 'lib/stdlib/src')
-rw-r--r--lib/stdlib/src/dets.erl25
-rw-r--r--lib/stdlib/src/dets_server.erl18
2 files changed, 30 insertions, 13 deletions
diff --git a/lib/stdlib/src/dets.erl b/lib/stdlib/src/dets.erl
index 76e03bbfaa..a4bd45ea19 100644
--- a/lib/stdlib/src/dets.erl
+++ b/lib/stdlib/src/dets.erl
@@ -2839,17 +2839,22 @@ fsck_try(Fd, Tab, FH, Fname, SlotNumbers, Version) ->
tempfile(Fname) ->
Tmp = lists:concat([Fname, ".TMP"]),
- tempfile(Tmp, 10).
-
-tempfile(Tmp, 0) ->
- Tmp;
-tempfile(Tmp, N) ->
case file:delete(Tmp) of
- {error, eacces} -> % 'dets_process_died' happened anyway... (W-nd-ws)
- timer:sleep(1000),
- tempfile(Tmp, N-1);
- _ ->
- Tmp
+ {error, _Reason} -> % typically enoent
+ ok;
+ ok ->
+ assure_no_file(Tmp)
+ end,
+ Tmp.
+
+assure_no_file(File) ->
+ case file:read_file_info(File) of
+ {ok, _FileInfo} ->
+ %% Wait for some other process to close the file:
+ timer:sleep(100),
+ assure_no_file(File);
+ {error, _} ->
+ ok
end.
%% -> {ok, NewHead} | {try_again, integer()} | Error
diff --git a/lib/stdlib/src/dets_server.erl b/lib/stdlib/src/dets_server.erl
index 268c201047..3164d40f35 100644
--- a/lib/stdlib/src/dets_server.erl
+++ b/lib/stdlib/src/dets_server.erl
@@ -1,7 +1,7 @@
%%
%% %CopyrightBegin%
%%
-%% Copyright Ericsson AB 2001-2013. All Rights Reserved.
+%% Copyright Ericsson AB 2001-2014. All Rights Reserved.
%%
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
@@ -171,9 +171,15 @@ handle_info({pending_reply, {Ref, Result0}}, State) ->
link(Pid),
do_link(Store, FromPid),
true = ets:insert(Store, {FromPid, Tab}),
- true = ets:insert(?REGISTRY, {Tab, 1, Pid}),
- true = ets:insert(?OWNERS, {Pid, Tab}),
+ %% do_internal_open() has already done the following:
+ %% true = ets:insert(?REGISTRY, {Tab, 1, Pid}),
+ %% true = ets:insert(?OWNERS, {Pid, Tab}),
{ok, Tab};
+ {Reply, internal_open} ->
+ %% Clean up what do_internal_open() did:
+ true = ets:delete(?REGISTRY, Tab),
+ true = ets:delete(?OWNERS, Pid),
+ Reply;
{Reply, _} -> % ok or Error
Reply
end,
@@ -309,6 +315,12 @@ do_internal_open(State, From, Args) ->
[T, _, _] -> T;
[_, _] -> Ref
end,
+ %% Pretend the table is open. If someone else tries to
+ %% open the file it will always become a pending
+ %% 'add_user' request. If someone tries to use the table
+ %% there will be a delay, but that is OK.
+ true = ets:insert(?REGISTRY, {Tab, 1, Pid}),
+ true = ets:insert(?OWNERS, {Pid, Tab}),
pending_call(Tab, Pid, Ref, From, Args, internal_open, State);
Error ->
{Error, State}