process callbacks first; they are supposed to remove modifications they successfully handled, so that regular modify function can complain if any unhandled modification remains

LDAP Content Sync in general and "syncrepl" should only be used
when referring to replication-specific functionality.

to already-freed memory. That bug still needs to be tracked down. This
patch deletes curcsn and just uses op->o_csn, which did not exist when
this code was originally written.

  syncrepl: don't save contextCSN on incoming context entry
  syncprov: delete contextCSN on checkpoint if ctxcsn is empty

cookie, that's only an intermediate value.
ITS#4622, don't update the context cookie until all the nonpresent
deletes are finished.

cleanup overlay list if overlay db_init fails.

busy unnecessarily

looking for, don't cache anything else.