Re: [PATCH] rules: block - add dm devices to whitelist

[Lennart Poettering <lennart@poettering.net>]

On Mon, 10.07.17 11:37, David Disseldorp (ddiss@suse.de) wrote:

> Thanks for the feedback, Lennart...
> 
> On Mon, 10 Jul 2017 10:38:38 +0200, Lennart Poettering wrote:
> 
> > On Wed, 05.07.17 13:01, David Disseldorp (ddiss@suse.de) wrote:
> > 
> > > Ceph relies on by-partuuid symlinks, in order to locate the journal
> > > partition from a given OSD partition. For details, see
> > > http://tracker.ceph.com/issues/19489.  
> > 
> > This appears way too broad, as it would apply to all LVM and all other
> > devices.
> >
> > It appears to me Ceph should do the same as LVM does for this, and
> > ship its own set of rules, and be careful to only match against the
> > actual devices it creates.
> 
> We can certainly do this in a Ceph specific manner via the existing
> 95-ceph-osd.rules, but my impression was that the by-partuuid symlinks
> are "owned" by 60-persistent-storage.rules .
> 
> If you don't think the existence of these symlinks for dm paths will be
> of use to others then I'll go ahead and propose it as a Ceph only
> change.

Hmmm, so thinking about this again: "partuuid" is actually for GPT
partition UUIDs if I recall recorrectly, they wouldn't be generated
for DM devices anyway, since they are one layer removed from the GPT,
so are you even sure this will do what you are asking for?

But even if this actually works: DM links so far are created by the
LVM/libdevicemapper/ packages, not by udev, and I don't think this
should change. Hence, please talk to the LVM/libdevicemapper folks
about this and ask them for including it.

Lennart

-- 
Lennart Poettering, Red Hat
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