Re: below top level mounting NFS3 authentication patch

["J. Bruce Fields" <bfields@fieldses.org>]

On Thu, Aug 14, 2008 at 01:42:19PM +0200, EG Keizer wrote:
> At our faculty we use Linux (Debian) clients and Solaris 9/10 file servers.
> We use the automounter on the Linux clients to access home directories with krb5.
> The servers  export the home directories on the level above the user home
> directories.
> Kernel 2.6.18 allows this behavior, kernels later then 2.6.23 do not.
> The underlying cause for the problem is the interpretation of the wording in
> RFC 2623, sec  2.3.2. This allows fsinfo with UNIX authentication on the
> root of the  export. But the automounter mounts below the root of the export/share
> and the Solaris  server (justly) requires full, i.e. krb5, authentication.
> Thus the mount fails, which makes the automounter useless in our environment.
> The client should try both authentications and use the first one that
> succeeds.
> The nfs_proc_get_root subroutine in nfs3proc already does
> this, but...
> the call to the sget routine earlier in the routine nfs_get_sb causes a
> fsinfo call that always uses UNIX authentication. Which causes the mount
> to fail.
>
> The solution i came up with is simple. Transplant the way get_root
> handles this to fsinfo. This is implemented in the patch to 2.6.24-rc4
> in the attachment.
>
> The are probably better solutions. For example by collapsing the two
> calls to get_root and fsinfo. But all i needed was something that made
> things work for me and did not ruin something for anybody.
>
> It would be nice if this patch found its way into the distribution...

Seems fine to me.  Doesn't v2 need the same treatment as v3 here,
though?

--b.

>
>
> Ed Keizer
> IT group                                        tel: +31 20 5987804
> Faculty of Sciences		                fax: +31 20 5987653
> Vrije Universiteit                              e-mail: keie-vHs5IaWfoDhmR6Xm/wNWPw@public.gmane.org
> De Boelelaan 1081A, 1081 HV  Amsterdam, The Netherlands
>
>
>

> diff --git a/fs/dcache.c b/fs/dcache.c
> diff --git a/fs/nfs/nfs3proc.c b/fs/nfs/nfs3proc.c
> index 4cdc236..1215d42 100644
> --- a/fs/nfs/nfs3proc.c
> +++ b/fs/nfs/nfs3proc.c
> @@ -687,7 +687,7 @@ nfs3_proc_statfs(struct nfs_server *server, struct nfs_fh *fhandle,
>  }
>  
>  static int
> -nfs3_proc_fsinfo(struct nfs_server *server, struct nfs_fh *fhandle,
> +do_proc_fsinfo(struct rpc_clnt *client, struct nfs_fh *fhandle,
>  		 struct nfs_fsinfo *info)
>  {
>  	struct rpc_message msg = {
> @@ -699,11 +699,26 @@ nfs3_proc_fsinfo(struct nfs_server *server, struct nfs_fh *fhandle,
>  
>  	dprintk("NFS call  fsinfo\n");
>  	nfs_fattr_init(info->fattr);
> -	status = rpc_call_sync(server->nfs_client->cl_rpcclient, &msg, 0);
> +	status = rpc_call_sync(client, &msg, 0);
>  	dprintk("NFS reply fsinfo: %d\n", status);
>  	return status;
>  }
>  
> +/*
> + * Bare-bones access to fsinfo: this is for nfs_get_root/nfs_get_sb via nfs_create_server
> + */
> +static int
> +nfs3_proc_fsinfo(struct nfs_server *server, struct nfs_fh *fhandle,
> +		   struct nfs_fsinfo *info)
> +{
> +	int	status;
> +
> +	status = do_proc_fsinfo(server->client, fhandle, info);
> +	if (status && server->nfs_client->cl_rpcclient != server->client)
> +		status = do_proc_fsinfo(server->nfs_client->cl_rpcclient, fhandle, info);
> +	return status;
> +}
> +
>  static int
>  nfs3_proc_pathconf(struct nfs_server *server, struct nfs_fh *fhandle,
>  		   struct nfs_pathconf *info)
>