Best practices: Adding Persistent Handle support

Tom Talpey ttalpey at
Mon Jun 5 13:45:43 UTC 2017

Snipping to just one topic for this...

> -----Original Message-----
> From: Christopher R. Hertel [mailto:crh at]
> Sent: Monday, June 5, 2017 12:12 AM
> To: Tom Talpey <ttalpey at>; Stefan Metzmacher
> <metze at>; Christoph Hellwig <hch at>
> Cc: samba-technical at
> Subject: Re: Best practices: Adding Persistent Handle support
> Responding to a few intertwined threads here...
> Tom:
> From one pedant to another, your clear definitions of Continued Availability
> and (vs.) Persistent Handles is quite helpful and appreciated.  From a
> practical perspective, it seems to me that if the SMB3 server does not have
> any shares that provide Continuous Availability, then it should not send
> SMB2_GLOBAL_CAP_PERSISTENT_HANDLES since it cannot actually provide
> Persistent Handles.

Well, that's not how Windows does it. Persistence is handled by an entirely
separate component, above the filesystems, called the Resume Key Filter (RKF).
The server global persistence *capability* reflects only the presence of this

The persistence *implementation*, on the other hand, is per-handle, and is
determined by the filesystem at handle creation time. Totally separate subsystems,
and although they often come and go together, they're not monolithic*.


* Monolithic: "One Big Rock" :-)

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