tdb: add TDB_MUTEX_LOCKING support
This adds optional support for locking based on
shared robust mutexes.
The caller can use the TDB_MUTEX_LOCKING flag
together with TDB_CLEAR_IF_FIRST after verifying
with tdb_runtime_check_for_robust_mutexes() that
it's supported by the current system.
The caller should be aware that using TDB_MUTEX_LOCKING
implies some limitations, e.g. it's not possible to
have multiple read chainlocks on a given hash chain
from multiple processes.
Note: that this doesn't make tdb thread safe!
Pair-Programmed-With: Stefan Metzmacher <metze@samba.org>
Pair-Programmed-With: Michael Adam <obnox@samba.org>
Signed-off-by: Volker Lendecke <vl@samba.org>
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Michael Adam <obnox@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
34 files changed: