[libvirt] [PATCH] libxl: add discard support to libxl_device_disk

[Olaf Hering]

On Fri, May 30, Jim Fehlig wrote:

> Olaf Hering wrote:
> > +    if (discard == VIR_DOMAIN_DISK_DISCARD_DEFAULT)
> > +        return;
> > +    virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> > +                   _("This version of libxenlight does not support "
> > +                     "discard= option passing"));
> An error would be reported here, but the overall libxlMakeDisk operation
> would succeed right?  Shouldn't it fail if the user requests discard but
> it is not supported?

How would libvirt know if the underlying backing store supports discard?
It would need to maintain a list of supported targets.
If it remains just some sort of warning a given .xml file can be shared
among different libvirt versions. After all, discard is not operation
critical.

Olaf