[dm-devel] libmultipath issue

[Martin Wilck]

Hi James,

On Tue, 2017-06-13 at 11:19 -0500, James Shoemaker wrote:
>    I have a piece of hardware, a 16 bay storagetek  optically
> connected SAN to
> be specific, that returns empty string for Device id.
> 
>    I did the following patch to resolve the issue, it basically
> allows empty
> string for vendor and product, I couldn't find anywhere that had an
> issue with
> it..
> 
> diff --git a/libmultipath/discovery.c b/libmultipath/discovery.c
> index 663c8ea..92d0e49 100644
> --- a/libmultipath/discovery.c
> +++ b/libmultipath/discovery.c
> @@ -1149,12 +1149,12 @@ scsi_sysfs_pathinfo (struct path * pp, vector
> hwtable)
>         if (!attr_path || pp->sg_id.host_no == -1)
>                 return 1;
> 
> -       if (sysfs_get_vendor(parent, pp->vendor_id, SCSI_VENDOR_SIZE)
> <= 0)
> +       if (sysfs_get_vendor(parent, pp->vendor_id, SCSI_VENDOR_SIZE)
> < 0)
>                 return 1;
> 
>         condlog(3, "%s: vendor = %s", pp->dev, pp->vendor_id);
> 
> -       if (sysfs_get_model(parent, pp->product_id,
> SCSI_PRODUCT_SIZE) <= 0)
> +       if (sysfs_get_model(parent, pp->product_id,
> SCSI_PRODUCT_SIZE) < 0)
>                 return 1;
> 
>         condlog(3, "%s: product = %s", pp->dev, pp->product_id);

In general, yes, I think this would work. vendor_id and product_id are
primarily used to lookup parameters in the hwtable, and there we have
no entries with empty vendor or product.

One side issue that needs to be considered is printout, though:
snprint_multipath_(vpr|prod|vend) will just print nothing if either
vendor or product has zero length. It would be good if they'd print
e.g. "<NOVNDR>" and "<NO PRODUCT>" instead.

Regards
Martin

PS: Patch in plain text format would be appreciated.

-- 
Dr. Martin Wilck <mwilck at suse.com>, Tel. +49 (0)911 74053 2107
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)