Re: setattr for vserver over NFS

On Tue, Dec 13, 2011 at 11:18:38AM -0700, Dan Urist wrote:
> I have a number of vservers running on a Debian lenny host that
> I'm planning to migrate to a squeeze host. The vservers' root
> filesystems are on NFS shares from a netapp.

> I've followed the instructions to set the barrier attribute here:
> http://linux-vserver.org/Secure_chroot_Barrier#Solution:_Secure_Barrier

> The problem I'm having is "setattr --barrier" doesn't appear to
> do anything for the NFS filesystems, as reported by showattr
> (it works for other vservers on ext3 filesystems, though).
> I've tried this on both the lenny and the squeeze hosts, with
> the filesystems mounted as both NFSv3 and NFSv4 (the netapp
> supports both). I've also tried mounting the filesystems with
> the "noac" option, which had no effect. Here are the package
> versions for the squeeze host:

> linux-image-2.6.32-5-vserver-amd64          2.6.32-39                    
> util-vserver                                0.30.216-pre2864-2+b1 

the barrier is not implemented for NFS as NFS doesn't
support xattr (which the barrier is based on) at all

but, with a recent kernel and recent util-vserver,
you won't be needing the barrier anyway ...

note that I do not know if the debian kernel/tools
are recent enough, so I'd suggest to ask the debian
folks about this case.

HTH,
Herbert

> Does anyone have any experience with running vservers over NFS?


> -- 
> Dan Urist
> [email protected]
> 303-497-2459