[PATCH RFC] nvme-rdma: Queue ns scanning after a sucessful reconnection

[J Freyensee]

On Sun, 2016-08-07 at 12:12 +0300, Sagi Grimberg wrote:
> > 
> > > 
> > > On an ordered target shutdown, the target can send a AEN on a
> > > namespace
> > > removal, this will trigger the host to queue ns-list query. The
> > > shutdown
> > > will trigger error recovery which will attepmt periodic
> > > reconnect.
> > > 
> > > We can hit a race where the ns rescanning fails (error recovery
> > > kicked
> > > in and we're not connected) causing removing all the namespaces
> > > and
> > > when
> > > we reconnect we won't see any namespaces for this controller.
> > > 
> > > So, queue a namespace rescan after we successfully reconnected to
> > > the
> > > target.
> > > 
> > > Note, that unlike user initiated controller reset, we don't need
> > > to
> > > trigger
> > > namespace scanning (until the point I noticed the above at least)
> > > because we
> > > reconnect to an existing controller. However due to the
> > > interaction
> > > with
> > > the aen mechanism we queue ns scan here as well.
> > > 
> > > Signed-off-by: Sagi Grimberg <sagi at grimberg.me>
> > > ---
> > > I'm open to other suggestions if anyone has any...
> > 
> > this sounds like a fix that should really go in the core target
> > code
> > instead of RDMA code as this could affect any implementation layer.
> 
> But it fixes the host behavior (nvme-rdma).

Actually I think I meant host but didn't have enough coffee for my
brain when I looked at this :-/...

OK, makes sense.