Re: [PATCH] BTT: Change nd_btt_arena_is_valid() to verify UUID

[Toshi Kani <toshi.kani@hpe.com>]

On Fri, 2015-12-18 at 09:54 -0800, Dan Williams wrote:
> On Fri, Dec 18, 2015 at 7:15 AM, Toshi Kani <toshi.kani@hpe.com> wrote:
> > On Fri, 2015-12-18 at 01:34 -0700, Vishal Verma wrote:
> > > Also, I wonder if this problem is solved by using libndctl to manage
> > > BTTs.
> > 
> > I have not tested with libndctl yet, but I think our bind/unbind 
> > scripts do the same procedures.
> 
> We loop through all combinations of sector size in our unit test.  If
> you want to change the sector size the expectation is that the
> namespace is destroyed and fully re-created, especially due to the
> fact that changing sector size invalidates all data on the namespace.
> 
> See: https://github.com/pmem/ndctl/blob/master/lib/test-libndctl.c

The parent_uuid is not set on our NVDIMM-N systems.  I do not see 'uuid'
file under sysfs 'namespaceX.X' per namespace_visible(), either.  This
concept of creating/destroying a namespace is a bit foreign to us since
we've never needed to do.  Can you elaborate how it's supposed to work for
NVDIMM-N?

Thanks,
-Toshi