[dm-devel] [PATCH 22/57] multipath: use option '-i' when called from udev

[Christophe Varoqui]

Ben,

does this patch actually break the Red Hat integration ?
I'm inclined to merge it if not.

Thanks,
Christophe

On Tue, May 3, 2016 at 7:44 AM, Hannes Reinecke <hare at suse.de> wrote:

> On 05/02/2016 05:31 PM, Benjamin Marzinski wrote:
> > On Wed, Apr 27, 2016 at 01:10:23PM +0200, Hannes Reinecke wrote:
> >> multipath should be using the option '-i' to ignore the wwids
> >> file when called from udev. Otherwise we might run into a race
> >> condition with systemd and the system might not boot up correctly.
> >
> > The race condition being? Are you talking about the udev rules not
> > claiming a path for multipath, but then having multipathd create a
> > multipath device using that path? I agree that this can be an issue.
> > Another way to solve it is to run mutipathd with the -n option in the
> > initramfs (see commit a8efa5838cf215febd853f282c26af62c0daa862). That
> > commit solves the race by making mutipathd ignore devices that aren't
> > already in the wwids file.  This also keeps the initramfs from picking a
> > different user_friendly_name than will be picked in late boot (but
> > hopefully that issue has been sorted out by other patches already).
> >
> This is in fact SUSE-specific, as we do _not_ require any a-priory
> configuration. So we will start out with a system without any wwid file,
> _but_ expect multipath to start up properly.
> As the wwid file will only be created by multipathd the udev check will
> always being false, and none of the multipath devices will be created.
>
> > I'm not NAKing this. The question of what to do about the differnces in
> > the distribution's systemd and udev configurations can be hashed out
> > outside of patch reviewing. I just want to make sure I understand the
> > race this is solving.
> >
> This is in fact a good question.
> We should be coming up with a common approach which would suit both needs.
>
> Cheers,
>
> Hannes
> --
> Dr. Hannes Reinecke                   zSeries & Storage
> hare at suse.de                          +49 911 74053 688
> SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
> GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
>
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