[libvirt] [PATCH] fix a ambiguous output of the command:'virsh vol-create-as'

[Daniel P. Berrange]

On Mon, Oct 07, 2013 at 10:48:30AM +0200, Michal Privoznik wrote:
> On 07.10.2013 07:20, Hongwei Bi wrote:
> > I created a storage volume(eg: test) from a storage pool(eg:vg10) using
> > the following command:"virsh vol-create-as --pool vg10 --name test --capacity 300M."
> > When I re-executed the above command, the output was as the following:
> > "error: Failed to create vol test
> >  error: Storage volume not found: storage vol 'test' already exists"
> > 
> > I think the output "Storage volume not found" is not appropriate. Because in fact storage
> > vol test has been found at this time. And then I think virErrorNumber should includes
> > VIR_ERR_STORAGE_EXIST which can also be used elsewhere. So I make this patch. The result
> > is as following:
> > "error: Failed to create vol test
> >  error: storage volume 'test' exists already"
> > 
> > ---
> >  include/libvirt/virterror.h  |    1 +
> >  src/storage/storage_driver.c |    4 ++--
> >  src/util/virerror.c          |    6 ++++++
> >  3 files changed, 9 insertions(+), 2 deletions(-)
> > 
> > diff --git a/include/libvirt/virterror.h b/include/libvirt/virterror.h
> > index c1960c8..28ef30a 100644
> > --- a/include/libvirt/virterror.h
> > +++ b/include/libvirt/virterror.h
> > @@ -296,6 +296,7 @@ typedef enum {
> >      VIR_ERR_ACCESS_DENIED = 88,         /* operation on the object/resource
> >                                             was denied */
> >      VIR_ERR_DBUS_SERVICE = 89,          /* error from a dbus service */
> > +    VIR_ERR_STORAGE_EXIST = 90,         /* the storage vol already exist */

I'd suggest this should be  VIR_ERR_STORAGE_VOL_EXISTS.

> 
> What about instead of inventing new error code re-use the old VIR_ERR_OPERATION_FAILED? Something like we have in virDomainObjListAddLocked:
> 
>         if (STRNEQ(vm->def->name, def->name)) {
>             virUUIDFormat(vm->def->uuid, uuidstr);
>             virReportError(VIR_ERR_OPERATION_FAILED,
>                            _("domain '%s' is already defined with uuid %s"),
>                            vm->def->name, uuidstr);
>             goto error;
>         }

I'd actually suggest that we should add a new error code for domains
and other object types too. I think it is useful to be explicit about
duplicate / clashing names/ids.

Regards,
Daniel
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