tree a68ac809ec45dd09d9a24250f8ebcf3825ccea23
parent 60446067ba7a8e890a91db3b4a7436fe0ebd2dee
author J. Bruce Fields <bfields@citi.umich.edu> 1181330614 -0400
committer J. Bruce Fields <bfields@citi.umich.edu> 1184800639 -0400

nfs: disable leases over NFS

As Peter Staubach says elsewhere
(http://marc.info/?l=linux-kernel&m=118113649526444&w=2):

> The problem is that some file system such as NFSv2 and NFSv3 do
> not have sufficient support to be able to support leases correctly.
> In particular for these two file systems, there is no over the wire
> protocol support.
>
> Currently, these two file systems fail the fcntl(F_SETLEASE) call
> accidentally, due to a reference counting difference.  These file
> systems should fail more consciously, with a proper error to
> indicate that the call is invalid for them.

Define an nfs setlease method that just returns -EINVAL.

If someone can demonstrate a real need, perhaps we could reenable
them in the presence of the "nolock" mount option.

Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Cc: Peter Staubach <staubach@redhat.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>