diff options
Diffstat (limited to 'lib/mnesia/src/mnesia_locker.erl')
| -rw-r--r-- | lib/mnesia/src/mnesia_locker.erl | 74 |
1 files changed, 62 insertions, 12 deletions
diff --git a/lib/mnesia/src/mnesia_locker.erl b/lib/mnesia/src/mnesia_locker.erl index cfa3f171b2..0492d794f3 100644 --- a/lib/mnesia/src/mnesia_locker.erl +++ b/lib/mnesia/src/mnesia_locker.erl @@ -1,7 +1,7 @@ %% %% %CopyrightBegin% %% -%% Copyright Ericsson AB 1996-2009. All Rights Reserved. +%% Copyright Ericsson AB 1996-2011. 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 @@ -40,7 +40,8 @@ sticky_wlock_table/3, wlock/3, wlock_no_exist/4, - wlock_table/3 + wlock_table/3, + load_lock_table/3 ]). %% sys callback functions @@ -49,6 +50,8 @@ system_code_change/4 ]). +-compile({no_auto_import,[error/2]}). + -include("mnesia.hrl"). -import(mnesia_lib, [dbg_out/2, error/2, verbose/2]). @@ -654,16 +657,17 @@ rwlock(Tid, Store, Oid) -> Lock = write, case need_lock(Store, Tab, Key, Lock) of yes -> - Ns = w_nodes(Tab), + {Ns, Majority} = w_nodes(Tab), + check_majority(Majority, Tab, Ns), Res = get_rwlocks_on_nodes(Ns, rwlock, Node, Store, Tid, Oid), ?ets_insert(Store, {{locks, Tab, Key}, Lock}), Res; no -> if Key == ?ALL -> - w_nodes(Tab); + element(2, w_nodes(Tab)); Tab == ?GLOBAL -> - w_nodes(Tab); + element(2, w_nodes(Tab)); true -> dirty_rpc(Node, Tab, Key, Lock) end @@ -675,12 +679,34 @@ rwlock(Tid, Store, Oid) -> %% in the local store under the key == nodes w_nodes(Tab) -> - Nodes = ?catch_val({Tab, where_to_write}), - case Nodes of - [_ | _] -> Nodes; + case ?catch_val({Tab, where_to_wlock}) of + {[_ | _], _} = Where -> Where; _ -> mnesia:abort({no_exists, Tab}) end. +%% If the table has the 'majority' flag set, we can +%% only take a write lock if we see a majority of the +%% nodes. + + +check_majority(true, Tab, HaveNs) -> + check_majority(Tab, HaveNs); +check_majority(false, _, _) -> + ok. + +check_majority(Tab, HaveNs) -> + case ?catch_val({Tab, majority}) of + true -> + case mnesia_lib:have_majority(Tab, HaveNs) of + true -> + ok; + false -> + mnesia:abort({no_majority, Tab}) + end; + _ -> + ok + end. + %% aquire a sticky wlock, a sticky lock is a lock %% which remains at this node after the termination of the %% transaction. @@ -706,12 +732,14 @@ sticky_lock(Tid, Store, {Tab, Key} = Oid, Lock) -> end. do_sticky_lock(Tid, Store, {Tab, Key} = Oid, Lock) -> + {WNodes, Majority} = w_nodes(Tab), + sticky_check_majority(Lock, Tab, Majority, WNodes), ?MODULE ! {self(), {test_set_sticky, Tid, Oid, Lock}}, N = node(), receive {?MODULE, N, granted} -> ?ets_insert(Store, {{locks, Tab, Key}, write}), - [?ets_insert(Store, {nodes, Node}) || Node <- w_nodes(Tab)], + [?ets_insert(Store, {nodes, Node}) || Node <- WNodes], granted; {?MODULE, N, {granted, Val}} -> %% for rwlocks case opt_lookup_in_client(Val, Oid, write) of @@ -719,7 +747,7 @@ do_sticky_lock(Tid, Store, {Tab, Key} = Oid, Lock) -> exit({aborted, C}); Val2 -> ?ets_insert(Store, {{locks, Tab, Key}, write}), - [?ets_insert(Store, {nodes, Node}) || Node <- w_nodes(Tab)], + [?ets_insert(Store, {nodes, Node}) || Node <- WNodes], Val2 end; {?MODULE, N, {not_granted, Reason}} -> @@ -735,6 +763,16 @@ do_sticky_lock(Tid, Store, {Tab, Key} = Oid, Lock) -> dirty_sticky_lock(Tab, Key, [N], Lock) end. +sticky_check_majority(W, Tab, true, WNodes) when W==write; W==read_write -> + case mnesia_lib:have_majority(Tab, WNodes) of + true -> + ok; + false -> + mnesia:abort({no_majority, Tab}) + end; +sticky_check_majority(_, _, _, _) -> + ok. + not_stuck(Tid, Store, Tab, _Key, Oid, _Lock, N) -> rlock(Tid, Store, {Tab, ?ALL}), %% needed? wlock(Tid, Store, Oid), %% perfect sync @@ -771,22 +809,33 @@ sticky_wlock_table(Tid, Store, Tab) -> %% local store when we have aquired the lock. %% wlock(Tid, Store, Oid) -> + wlock(Tid, Store, Oid, _CheckMajority = true). + +wlock(Tid, Store, Oid, CheckMajority) -> {Tab, Key} = Oid, case need_lock(Store, Tab, Key, write) of yes -> - Ns = w_nodes(Tab), + {Ns, Majority} = w_nodes(Tab), + if CheckMajority -> + check_majority(Majority, Tab, Ns); + true -> + ignore + end, Op = {self(), {write, Tid, Oid}}, ?ets_insert(Store, {{locks, Tab, Key}, write}), get_wlocks_on_nodes(Ns, Ns, Store, Op, Oid); no when Key /= ?ALL, Tab /= ?GLOBAL -> []; no -> - w_nodes(Tab) + element(2, w_nodes(Tab)) end. wlock_table(Tid, Store, Tab) -> wlock(Tid, Store, {Tab, ?ALL}). +load_lock_table(Tid, Store, Tab) -> + wlock(Tid, Store, {Tab, ?ALL}, _CheckMajority = false). + %% Write lock even if the table does not exist wlock_no_exist(Tid, Store, Tab, Ns) -> @@ -1102,6 +1151,7 @@ do_stop() -> system_continue(_Parent, _Debug, State) -> loop(State). +-spec system_terminate(_, _, _, _) -> no_return(). system_terminate(_Reason, _Parent, _Debug, _State) -> do_stop(). |