[PATCH] knfsd: call lockd_down when closing a socket via a write to nfsd/portlist

The refcount that nfsd holds on lockd is based on the number of open sockets.
So when we close a socket, we should decrement the ref (with lockd_down).

Currently when a socket is closed via writing to the portlist file, that
doesn't happen.

So: make sure we get an error return if the socket that was requested does is
not found, and call lockd_down if it was.

Cc: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/nfsd/nfsctl.c

@@ -545,6 +545,8 @@ static ssize_t write_ports(struct file *file, char *buf, size_t size)
 		if (nfsd_serv)
 			len = svc_sock_names(buf, nfsd_serv, toclose);
 		unlock_kernel();
+		if (len >= 0)
+			lockd_down();
 		kfree(toclose);
 		return len;
 	}