diff options
Diffstat (limited to 'lib/mnesia/src/mnesia_locker.erl')
| -rw-r--r-- | lib/mnesia/src/mnesia_locker.erl | 33 |
1 files changed, 32 insertions, 1 deletions
diff --git a/lib/mnesia/src/mnesia_locker.erl b/lib/mnesia/src/mnesia_locker.erl index ca0cc79c45..9822dfd116 100644 --- a/lib/mnesia/src/mnesia_locker.erl +++ b/lib/mnesia/src/mnesia_locker.erl @@ -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 @@ -657,6 +658,7 @@ rwlock(Tid, Store, Oid) -> case need_lock(Store, Tab, Key, Lock) of yes -> Ns = w_nodes(Tab), + check_majority(Tab, Ns), Res = get_rwlocks_on_nodes(Ns, rwlock, Node, Store, Tid, Oid), ?ets_insert(Store, {{locks, Tab, Key}, Lock}), Res; @@ -683,6 +685,28 @@ w_nodes(Tab) -> _ -> 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. @@ -773,10 +797,14 @@ 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), + check_majority(CheckMajority, Tab, Ns), Op = {self(), {write, Tid, Oid}}, ?ets_insert(Store, {{locks, Tab, Key}, write}), get_wlocks_on_nodes(Ns, Ns, Store, Op, Oid); @@ -789,6 +817,9 @@ wlock(Tid, Store, Oid) -> 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) -> |