Work on SMB3 persistent handles

[Christopher R. Hertel]

On 10/30/2017 03:48 PM, Volker Lendecke wrote:
> On Mon, Oct 30, 2017 at 12:04:29PM -0500, Christopher R. Hertel via samba-technical wrote:
>> The model that Ralph and I (and others) discussed last September at the
>> Storage Developers Conference (SDC) was, indeed, coupled on CTDB.  I am sure
>> Ralph will correct me if I misstate, but as I understand it there was a
>> strong desire within the Samba Team to ensure that Samba itself--without any
>> FS-specific modifications--could provide Persistent Handle support.
> 
> The main reason for this is end-to-end testability without any special
> file system support. We might of course compromise on efficiency, but
> the functionality must (IMHO) be testable on a pretty plain posix
> system. This is also in the interest of any OEM, because otherwise we
> (the Samba Team) will definitely break the infrastructure around
> persistent file handles sooner or later, and OEMs usually notice only
> months later when they pull in a fresh upstream release.

...and that makes perfect sense.

Note also that with such an implementation you could even create Persistent
Handles on non-clustered file systems, such as XFS or EXT4.  This would be
useful, for example, on systems that can reboot quickly after a catastrophic
failure, or in those rare cases in which an smbd instance crashes.

However, several vendors (including the one that employs me) have expressed
the desire to be able to integrate Persistent Handle support into their
existing cluster file system infrastructure.

Chris -)-----