From mboxrd@z Thu Jan 1 00:00:00 1970 From: "J. Bruce Fields" Subject: Re: [PATCH] cifs: Allow nfsd over cifs Date: Tue, 1 Mar 2011 15:48:07 -0500 Message-ID: <20110301204807.GF20599@fieldses.org> References: <20110228235910.GD14237@fieldses.org> <20110301032808.GA17725@fieldses.org> <20110301180700.GC20599@fieldses.org> <20110301192102.GD20599@fieldses.org> <20110301150949.6ca5b880@tlielax.poochiereds.net> <20110301203445.GE20599@fieldses.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Jeff Layton , Shirish Pargaonkar , linux-cifs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Steve French Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-cifs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: On Tue, Mar 01, 2011 at 02:38:27PM -0600, Steve French wrote: > On Tue, Mar 1, 2011 at 2:34 PM, J. Bruce Fields wrote: > > On Tue, Mar 01, 2011 at 02:11:32PM -0600, Steve French wrote: > >> I vaguely remember that the same problem can occur with nfsd on a > >> local file system > > > > Not true; as I've said, exportable local filesystems know how to lo= ok up > > a file on disk by filehandle. > > > >> and that nfs clients have to be able to recover from > >> ESTALE (e.g. lookup/delete/create/lookup would fail with ESTALE > >> otherwise). > > > > It is true, however, that there are some *other* cases when a serve= r can > > return ESTALE. =C2=A0In those cases (such as the one Peter Staubach= discusses > > in more detail at http://lwn.net/Articles/272684/) there may be som= e > > recovery that a client might reasonably attempt. > > > > Alas, no client can be expected to recover from ESTALE errors on an > > opened file--those will just be passed on to the application. >=20 > If this is v4 (only) wouldn't we always have an open->dentry in cache= ? That's correct, but only as long as the server is running. We need reboot recovery to work as well. Also: - NFSv4 uptake is still rather small as far as I know, so the v3 behavior is important - We don't currently have any way to export cifs as v4 only. --b.