Re: Grace period

["Myklebust, Trond" <Trond.Myklebust@netapp.com>]

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On Mon, 2012-04-09 at 12:11 -0400, bfields@fieldses.org wrote:
> On Mon, Apr 09, 2012 at 08:08:57PM +0400, Stanislav Kinsbursky wrote:
> > 09.04.2012 19:27, Jeff Layton пишет:
> > >
> > >If you allow one container to hand out conflicting locks while another
> > >container is allowing reclaims, then you can end up with some very
> > >difficult to debug silent data corruption. That's the worst possible
> > >outcome, IMO. We really need to actively keep people from shooting
> > >themselves in the foot here.
> > >
> > >One possibility might be to only allow filesystems to be exported from
> > >a single container at a time (and allow that to be overridable somehow
> > >once we have a working active/active serving solution). With that, you
> > >may be able limp along with a per-container grace period handling
> > >scheme like you're proposing.
> > >
> > 
> > Ok then. Keeping people from shooting themselves here sounds reasonable.
> > And I like the idea of exporting a filesystem only from once per
> > network namespace.
> 
> Unfortunately that's not going to get us very far, especially not in the
> v4 case where we've got the common read-only pseudoroot that everyone
> has to share.

I don't see how that can work in cases where each container has its own
private mount namespace. You're going to have to tie that pseudoroot to
the mount namespace somehow.

-- 
Trond Myklebust
Linux NFS client maintainer

NetApp
Trond.Myklebust@netapp.com
www.netapp.com

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