s3:dbwrap_ctdb: fix a race in starting concurrent transactions on a single node
There are two races in concurrent transactions on a single node.
One in starting a transaction and one with replay during commit.
This commit closes the first race by storing the client pid in the
transaction-lock record and comparing the stored pid against its own
pid after releasing the lock and refetching the record inside the
transaction.
Michael
Signed-off-by: Michael Adam <obnox@samba.org>
(cherry picked from commit
7b37b8a5dcc08817b21e12570da6632674cc7575)