RE: "exportfs -a" -> stale NFS filehandle

["Kaz Kylheku" <kaz@zeugmasystems.com>]

Ralf Baechle wrote:
> On Thu, Nov 15, 2007 at 11:26:06AM -0800, Kaz Kylheku wrote:
> 
>> After backing out the nfsutils patch, the diskless node does boot.
>> 
>> However, the original "exportfs -a" problem comes back!
>> 
>> So this problem is not resolved simply by using the correct compat
>> routine; it's deeper. 
>> 
>> Sigh.
> 
> Thanks for testing anyway!

I'm continuing to dig into the problem.

The export logic doesn't even go through nfsctl() anyway, which is why I
originally hadn't even suspected that syscall.

The nfsexport() function in nfsutils first tries opening
"/proc/net/rpc/nfsd.fh./channel". If that works, it uses that, via a
text-based protocol. Only if that interface doesn't exist does it fall
back on the nfsctl(NFSCTL_EXPORT, ...) interface.