RE: [GIT PULL] Please pull NFS client bugfixes and cleanups
From: Myklebust, Trond
Date: Mon Jan 09 2012 - 17:29:06 EST
> -----Original Message-----
> From: Wolfgang Walter [mailto:wolfgang.walter@xxxxxxx]
> Sent: Monday, January 09, 2012 5:15 PM
> To: Myklebust, Trond
> Cc: Linus Torvalds; linux-nfs@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [GIT PULL] Please pull NFS client bugfixes and cleanups
>
> On Monday 09 January 2012, Trond Myklebust wrote:
> > Hi Linus,
> >
> > Please pull from the "nfs-for-3.3" branch of the repository at
> >
> > git pull git://git.linux-nfs.org/projects/trondmy/linux-nfs.git
> > nfs-
> for-3.3
> >
> > This will update the following files through the appended changesets.
> >
> > Cheers,
> > Trond
> >
> >
> > commit 074b1d12fe2500d7d453902f9266e6674b30d84c
> > Author: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
> > Date: Mon Jan 9 13:46:26 2012 -0500
> >
> > NFSv4: Change the default setting of the nfs4_disable_idmapping
> parameter
> >
> > Now that the use of numeric uids/gids is officially sanctioned in
> > RFC3530bis, it is time to change the default here to 'enabled'.
> >
> > By doing so, we ensure that NFSv4 copies the behaviour of NFSv3
> > when
> we're
> > using the default AUTH_SYS authentication (i.e. when the client uses the
> > numeric uids/gids as authentication tokens), so that when new files are
> > created, they will appear to have the correct user/group.
> > It also fixes a number of backward compatibility issues when migrating
> > from NFSv3 to NFSv4 on a platform where the server uses different
> uid/gid
> > mappings than the client.
> >
> > Note also that this setting has been successfully tested against servers
> > that do not support numeric uids/gids at several
> Connectathon/Bakeathon
> > events at this point, and the fall back to using string names/groups has
> > been shown to work well in all those test cases.
> >
> > Signed-off-by: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
> >
>
>
> Does this mean that one has to modify all one's clients to get the old
> behaviour?
>
> I'm not sure if this is a really good idea. I don't see the advantage. This will
> break a lot of existing installations when upgrading to >=3.3. And someone
> migrating from NFSv3 to NFSv4 has to give some thoughts to it anyway.
Please read the changelog and documentation:
If your server doesnât support numeric uids/gids, then you will see _no_ change in behaviour.
If your server does support numeric uids/gids, and has the same mapping between numeric uids/gids and username/groupname as your clients, then you will see _no_ change in behaviour.
If your server does support numeric uids/gids, but the mapping between numeric uids/gids and username/groupname differs between server and client (e.g.. uid=20 maps to different users on the client and server) then you already had a problem in that creating the file using NFSv4 would result in you seeing the wrong owner and/or group. If this case, and this case only, the change to nfs4_disable_idmapper will result in you now seeing the correct owner/group for these files (just as if you were using NFSv3).
IOW: the only people who will want to use the old setting are those with broken servers that return incorrect errors when confronted with a numeric uid/gid. We have found no evidence that any such servers exist during the last full year of testing.
Trond
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