Work on SMB3 persistent handles

Michael Adam obnox at
Mon Oct 23 23:11:00 UTC 2017

On 2017-10-24 at 00:58 +0200, Michael Adam via samba-technical wrote:
> On 2017-10-23 at 13:17 -0500, Christopher R. Hertel wrote:
> > Michael:  Thanks for calling my attention to this thread.
> > 
> > You wrote:
> > > Maybe, if appropriate, someone could summarize the latest
> > > state of the discussions/design/prototyping...
> > 
> > I can summarize my own status:
> > 
> > * I have done the work necessary to negotiate Persistent Handle support in
> > the Session Setup.  Similarly, I have added per-share configuration to
> > support Continuous Availability in the Tree Connect.  Both of these
> > additions work nicely.
> > 
> > * Internally to Samba, I have added fields and flags that identify a share
> > as being CA, and a file handle as being Persistent.
> > 
> > Those are basic steps needed to negotiate Continuous Availability on the
> > wire, and to signal internally that CA is in use.
> > 
> > In theory, given the way that Durable Handle data is stored, we *should* be
> > able to pass Persistent Handle tests in this configuration.  As long as the
> > Samba node that owns the handle does not actually go down (that is, as long
> > as the test is performed by dropping the network connection), the data
> > should be maintained and we should be able to re-establish the Persistent
> > Handle.
> > 
> > I'm not quite there yet.  I am not yet sending back the correct blob
> > following the recovery.  This *should* be an easy fix.
> Since we've been talking about this a bit now, I've revived the
> patches that Metze and I had in our WIP branches since 2012, have
> rebased them on top of current master and made them work again.
> It's mainly the protocol boilerplate code. I.e. there is no
> persistence of the DBs or records, also the subtleties of how
> persistent handles are different from durable handles in semantic
> are not all covered yet, in particular no calling of
> SMB_VFS_DURABLE_DISCONNECT() under other circumstances than
> before, but for a start it does survive our (smbtorture's)
> durable-v2-open test (against nt4_dc) including the persistent
> open tests. Nothing fancy yet but just for comparing.
> Also attached for convenience.

Warning... I just noticed that this was not rebased to
the latest state of master but a few days back.
So it does (of course) not cleanly rebase on top of
Ralph's refactoring of smbd_smb2_create_send(). ;-)

Will look into it...

Cheers - Michael
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