[libvirt] [PATCH] xen: Fix bogus error when attaching a device

[Daniel P. Berrange]

On Tue, Oct 05, 2010 at 09:48:24AM -0400, Laine Stump wrote:
> 
> >The xm internal xen driver only supports disk and network devices to be
> >added to a guest. On an attempt to attach any other device the xm driver
> >used VIR_ERR_XML_ERROR which resulted in a completely bogus error
> >message:
> >
> >error: Failed to attach device from pci.xml
> >error: XML description for unknown device is not well formed or invalid
> >---
> >  src/xen/xm_internal.c |    4 ++--
> >  1 files changed, 2 insertions(+), 2 deletions(-)
> >
> >diff --git a/src/xen/xm_internal.c b/src/xen/xm_internal.c
> >index fcc9378..00f0df8 100644
> >--- a/src/xen/xm_internal.c
> >+++ b/src/xen/xm_internal.c
> >@@ -2980,8 +2980,8 @@ xenXMDomainAttachDeviceFlags(virDomainPtr domain, 
> >const char *xml,
> >      }
> >
> >      default:
> >-        xenXMError(VIR_ERR_XML_ERROR,
> >-                   "%s", _("unknown device"));
> >+        xenXMError(VIR_ERR_OPERATION_INVALID, "%s",
> >+                   _("Xm driver only supports adding disk or network 
> >devices"));
> >          goto cleanup;
> >      }
> >
> 
> It looks like many other similar errors in other drivers use 
> VIR_ERR_CONFIG_UNSUPPORTED. Would that maybe be a better choice than 
> VIR_ERR_OPERATION_INVALID, which seems to be used when something 
> normally valid is attempted while in an inavalid state (eg, trying to 
> stop a domain when it's already stopped, or perform some operation that 
> can be done only when a domain is stopped, but it's currently running.)

That is correct, OPERATION_INVALID is for reporting an operation that
could succeed, if the guest were in the correct lifecycle state.

If 'Xen' doesn't support this type of device at all, then CONFIG_UNSUPPORTED
is the better choice.

Regards,
Daniel
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