Re: NFS4 crack

[Peter Staubach <staubach@redhat.com>]

Bryan Henderson wrote:

>
>It would be good to understand whether the NFS server is in the kernel for 
>basic structural reasons or just because we're too lazy to invent this new 
>system call interface, because that sheds light on how a normally user 
>space problem like storing persistent application data for NFSv4 should be 
>approached.  Do we need a new kernel paradigm that admits file and 
>filename use within the kernel, or do we hold our nose and say, "what's 
>one more hack on top of an existing one?"
>

The NFS server is in the kernel for basic structural reasons, but also for
performance reasons.  I would be happy to hear and/or read a proposal on
how to get packets containing requests and/or responses in and out of the
kernel without copying them.  Inside of the kernel, both can be handled
with no copies.

It isn't that we are too lazy, by the way.  This issue gets looked into
every so often.  The set of system calls can be determined pretty quickly
and implementing them, while tricky in spots, can be done.  However, the
ugliness of the implementation soon starts to overwhelm the cleanliness
of the design.

--

I would even be happy with seeing a user mode local disk based file system
which performed as well as a kernel mode file system.  That seems easier to
to me because then there wouldn't be any of those sticky networking issues
to worry about.  When we get this, then we can consider the value of moving
something like NFS too.

    Thanx...

       ps