Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:51076 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754965AbdELN1X (ORCPT ); Fri, 12 May 2017 09:27:23 -0400 Date: Fri, 12 May 2017 09:27:21 -0400 From: Stefan Hajnoczi To: Chuck Lever Cc: Linux NFS Mailing List , "J. Bruce Fields" , Steve Dickson Subject: EXCHANGE_ID with same network address but different server owner Message-ID: <20170512132721.GA654@stefanha-x1.localdomain> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="7AUc2qLy4jB3hD7Z" Sender: linux-nfs-owner@vger.kernel.org List-ID: --7AUc2qLy4jB3hD7Z Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Hi, I've been working on NFS over the AF_VSOCK transport (https://www.spinics.net/lists/linux-nfs/msg60292.html). AF_VSOCK resets established network connections when the virtual machine is migrated to a new host. The NFS client expects file handles and other state to remain valid upon reconnecting. This is not the case after VM live migration since the new host does not have the NFS server state from the old host. Volatile file handles have been suggested as a way to reflect that state does not persist across reconnect, but the Linux NFS client does not support volatile file handles. I saw NFS 4.1 has a way for a new server running with the same network address of an old server to communicate that it is indeed a new server instance. If the server owner/scope in the EXCHANGE_ID response does not match the previous server's values then the server is a new instance. The implications of encountering a new server owner/scope upon reconnect aren't clear to me and I'm not sure to what extent the Linux implementation handles this case. Can anyone explain what happens if the NFS client finds a new server owner/scope after reconnecting? Thanks, Stefan --7AUc2qLy4jB3hD7Z Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEcBAEBAgAGBQJZFbg5AAoJEJykq7OBq3PILB4IAJpZ7PaJzw9ClUMTQcvgjMGi 50i+v64yRyX3h4WbX3kgd7o5iJjviUMgUBjs2pwSi7PP/9R+owkP1OsnI6wmrqCy gVHbnL18qVDrA+MsTpBIYmz8GIOG664ylsca/C5qv0JHal5j1wgN6TvYAofjrfKh imJBlf6ByrYhiUCHTCI3OOODut6irBiwS2CXup9tcsNyFOgAkuDLsNFy5B1DpeU3 8ecOZOY3RRkXck/zyGmKuG3WkuyDLorwuiM+8kPVxhpG9ipiUPmoCQy7mHo5iDDs +UtbSZqYIeDgywOKOcrjJdQrkKMCa4usqlhCPUiEXJBqZ39f6DG+RyEZ88J6Cbw= =Q0WZ -----END PGP SIGNATURE----- --7AUc2qLy4jB3hD7Z--