If you want your Linux box to act as an NFS *server*, so that other
computers on your local network which support NFS can access certain
directories on your box transparently, you have two options: you can
use the self-contained user space program nfsd, in which case you
should say N here, or you can say Y and use the kernel based NFS
server. The advantage of the kernel based solution is that it is
faster.

In either case, you will need support software; the respective
locations are given in the file Documentation/Changes in the
NFS section.

If you say Y here, you will get support for version 2 of the NFS
protocol (NFSv2). If you also want NFSv3, say Y to the next question
as well.

Please read the NFS-HOWTO, available from
<http://www.tldp.org/docs.html#howto>.

To compile the NFS server support as a module, choose M here: the
module will be called nfsd. If unsure, say N.

source code:

fs/nfsd/