NFSv4: Don't use the delegation->inode in nfs_mark_return_delegation()

NFSv4: Don't use the delegation->inode in nfs_mark_return_delegation()

commit ed1e6211a0a134ff23592c6f057af982ad5dab52 upstream.

nfs_mark_return_delegation() is usually called without any locking, and
so it is not safe to dereference delegation->inode. Since the inode is
only used to discover the nfs_client anyway, it makes more sense to
have the callers pass a valid pointer to the nfs_server as a parameter.

Reported-by: Ian Kent <raven@themaw.net>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>