Re: fs-independent quotas

[Jared McNeill <jmcneill%invisible.ca@localhost>]

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On Thu, 20 Oct 2011, Manuel Bouyer wrote:
> > also it doesn't support cursors.
>
> This can easily be implemented in userland, without changes to the
> quotactl(2) interface. I've trouble seeing how this can be sanely
> implemented at the quotactl(2) level (I don't like the idea of the
> kernel keeping states about what a specific userland process is doing).

Heyas Manuel --

You don't need to track state in the kernel, you just need to keep a 
generation ID. Have the caller pass a "starting index" and "requested 
count" parameter, and have the kernel include "number of matches", "total 
matches", and "generation ID" in the response. Let the kernel limit 
the maximum number of matches to return per request if you like. If 
the generation ID changes while the caller is fetching records you simply 
restart the process.

Cheers,
Jared
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