tdb_transaction_cancel

[tridge at samba.org]

Taj,

 > here's a contrived test case.  it aborts with the latest tdb in svn,
 > but works ok with the tdb in samba4-tp4.
 > 
 > could someone please confirm if this is a bug, or a
 > misunderstanding/misuse of the tdb api on my part?

you are absolutely right.

Volker, this seems to have been broken by r21303 in Samba3. Can you
remember why you removed the 
   tdb->locked[h].count = 0;
line in that commit? Without that line the tdb still thinks the tdb is
locked after a transaction cancel.

I know the code has to change, as lockrecs is now dynamic, but I think
we need something equivalent there. Perhaps we can just deleting the
list? You are not allowed to start a transaction when locks are held,
so we should be able to wipe the lock list when the transaction is
cancelled.

Cheers, Tridge