On Mon, 2020-02-10 at 14:49 -0600, Benjamin Marzinski wrote:
> On Mon, Feb 10, 2020 at 02:49:38PM +0000, Martin Wilck wrote:
> > On Wed, 2020-02-05 at 12:58 -0600, Benjamin Marzinski wrote:
> > > This adds the wildcard 'g' for multipath and path formatted
> > > printing,
> > > which returns extra data from a device's vendor specific vpd
> > > page. The
> > > specific vendor vpd page to use, and the vendor/product id to
> > > decode
> > > it
> > > can be set in the hwentry with vpd_vendor_pg and vpd_vendor_id.
> > > It
> > > can
> > > be configured in the devices section of multipath.conf with the
> > > vpd_vendor parameter. Currently, the only devices that use this
> > > are
> > > HPE
> > > 3PAR arrays, to return the Volume Name.
> > >
> > > Signed-off-by: Benjamin Marzinski <bmarzins@xxxxxxxxxx>
> > > ---
> > > libmultipath/config.c | 2 ++
> > > libmultipath/config.h | 1 +
> > > libmultipath/dict.c | 38
> > > ++++++++++++++++++++++++++++++++++++
> > > libmultipath/discovery.c | 40
> > > +++++++++++++++++++++++++++++++++++++-
> > > libmultipath/hwtable.c | 1 +
> > > libmultipath/print.c | 25 ++++++++++++++++++++++++
> > > libmultipath/propsel.c | 18 +++++++++++++++++
> > > libmultipath/propsel.h | 1 +
> > > libmultipath/structs.h | 15 ++++++++++++++
> > > multipath/multipath.conf.5 | 8 ++++++++
> > > 10 files changed, 148 insertions(+), 1 deletion(-)
> > >
> > > struct sg_id {
> > > int host_no;
> > > int channel;
> > > @@ -255,6 +268,7 @@ struct path {
> > > char rev[PATH_REV_SIZE];
> > > char serial[SERIAL_SIZE];
> > > char tgt_node_name[NODE_NAME_SIZE];
> > > + char vpd_data[VPD_DATA_SIZE];
> >
> > Hm, 128 more bytes per path for a rarely-used property... do we
> > need to
> > store this in "struct path"? Can't we simply fetch that information
> > when someone requests it with the %g format wildcard? It doesn't
> > matter
> > much today as "struct path" is really thick already, but I have
> > hopes
> > to make it a bit leaner some day.
>
> Well, the thought was that this information (which should help map
> the
> path to a physical array) would most often be wanted when things were
> going badly, and you might not be able to access the device.
Point taken. How about using a pointer? That would be only 8 extra
bytes for those cases where the field was unused.
Call me old-fashioned, I've grown up in a world where 1000x128 bytes
mattered.
Regards,
Martin
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