[OpenAFS-devel] Re: [OpenAFS] 2.6 kernel support anytime soon?Workarounds?

[Douglas E. Engert]

Derrick J Brashear wrote:
> 
> Ok, that's great. So, what should we do about it?
> 
> Remember that it needs to work with most of the distributed kernels from
> vendors, because once we require a rebuild we could just require a kernel
> patch, and fundamentally we don't want to do either. So given either
> working what what's in the kernel now, or getting a patch adopted are
> required, what should we do?
> 

Is there another way to look at the PAG problem rather then having to
use the groups? Using the groups to store a PAG was a convenience for 
the AFS Kernel routines to find credentials associated with a process,
but does not appear to be a requirement. 

If push comes to shove, (as it appears it has!) could the AFS
code in effect shadow the process table (or task_struct), so when a request
is needed if it has not seen this process before, it will look at the parent 
and on up the chain to find a process it has seen that has a "PAG".

The "setpag" syscall would in effect cause the shadow of the process
table to be updated indicating that this process is the Process
Authentication Group Leader. 

In Linux 2.6 the address of the task_struct and its start_time 
might be all that needs to be shadowed along with some garbage 
collection.  
 
This may be more overhead, but it get the PAG out of the groups,
and does not require trapping the setgroups syscall. 


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-- 

 Douglas E. Engert  <DEEngert@anl.gov>
 Argonne National Laboratory
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