[OpenAFS] best practice for salvage

[Jeffrey Altman]

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John Hascall wrote:
>> Since the file server has no way of knowing if the file is still in
>> use it can't delete it.
> 
>    Why not?  Is there no way for the file server to query the
>    cache manager and ask?

The fact that the file is considered temporary is only known to the
client.  AFS is not like SMB servers that issue file handles to
clients in response to an "open" call and destroy them whenever the
client becomes unresponsive.  AFS is designed to work across WANs
in which it is expected that network connectivity will be interrupted
or that a client will migrate.

The only reason that the files are deleted at all by the Salvager
is because the files were renamed to .__afsNNNN.  If the application
had created temporary files with some other name and then disappeared
without deleting them they would not be deleted by the salvager.

The way I would have implemented this functionality would be for the
file to be moved into the local client's cache and removed from the
file server since the file has now been unlinked and can therefore
not be referenced by other clients.  It would then be the client's
responsibility to clean up after itself.

Of course, even if we do implement this functionality in a future client
revision we can't fix the clients that are already deployed.



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