[dm-devel] [PATCH 1/3] libmultipath: keep existing dm_info if you fail to get a new one

[Benjamin Marzinski]

On Fri, Dec 03, 2021 at 08:01:11AM +0000, Martin Wilck wrote:
> On Thu, 2021-12-02 at 19:34 -0600, Benjamin Marzinski wrote:
> > There are reasons that dm_get_info() can fail other than the
> > multipath
> > device not existing. If there is an existing dm_info structure and
> > the
> > call fails, don't free it.
> > 
> > Signed-off-by: Benjamin Marzinski <bmarzins at redhat.com>
> 
> This is ok, but I think it'd be better to simply embed the dmi struct
> in struct multipath and thus avoid having allocate and free it
> separately. Either that, or just use a struct dm_info on stack  in
> dm_get_info() and just copy the properties we actually look at, i.e.
> read_only, major, minor, suspended, to respective fields in struct
> multipath. I'd prefer embedding the complete dmi, as it's not that
> large and contains other interesting fields, too (for example, we might
> be able to leverage the event_nr field to avoid duplicate work between
> uevent and dmevent handlers).
> 
> We would need to be able to figure out if the dmi is valid, but that's
> rather easy, we could simply set major = minor = 0.


Makes sense. I can change this.

-Ben

> 
> Regards
> Martin