On Fri, Jan 22, 2010 at 04:21:09PM -0700, Jim Fehlig wrote:
> Daniel P. Berrange wrote:
> > On Tue, Jan 19, 2010 at 07:40:14PM +0000, Daniel P. Berrange wrote:
> >
> >> On Thu, Jan 14, 2010 at 10:42:41AM -0700, Jim Fehlig wrote:
> >>
> >>> Implementation of public API for virDomain{Attach,Detach}DeviceFlags.
> >>> ---
> >>> src/libvirt.c | 106 ++++++++++++++++++++++++++++++++++++++++++++++++++++----
> >>> 1 files changed, 98 insertions(+), 8 deletions(-)
> >>>
> >>> diff --git a/src/libvirt.c b/src/libvirt.c
> >>> index 1145561..77f76bc 100644
> >>> --- a/src/libvirt.c
> >>> +++ b/src/libvirt.c
> >>> @@ -5129,7 +5129,6 @@ error:
> >>> int
> >>> virDomainAttachDevice(virDomainPtr domain, const char *xml)
> >>> {
> >>> - virConnectPtr conn;
> >>> DEBUG("domain=%p, xml=%s", domain, xml);
> >>>
> >>> virResetLastError();
> >>> @@ -5147,17 +5146,63 @@ virDomainAttachDevice(virDomainPtr domain, const char *xml)
> >>> virLibDomainError(domain, VIR_ERR_OPERATION_INVALID, __FUNCTION__);
> >>> goto error;
> >>> }
> >>> +
> >>> + return virDomainAttachDeviceFlags(domain, xml,
> >>> + VIR_DOMAIN_DEVICE_MODIFY_LIVE);
> >>> +
> >>> +error:
> >>> + virDispatchError(domain->conn);
> >>> + return -1;
> >>> +}
> >>>
> >> This looks safe, but there's a subtle problem with changing the existing
> >> virDomainAttachDevice() entry point to call virDomainAttachDeviceFlags().
> >> It will break compatability with old libvirtd, even though the old
> >> libvirtd supports the virDomainAttachDevice() code.
>
> Ah, yes - good catch. Thanks.
>
> >> So we need to keep
> >> the distinct paths in the public API & driver definitions. The eventual
> >> low level hypervisor drivers can of course just turn their existing
> >> impl into a thin wrapper to the new method..
> >>
> >
> > There's one other option actually - we could put compatability code in
> > the remote driver client instead. Either, make it always invoke the old
> > RPC call if flags == VIR_DOMAIN_DEVICE_MODIFY_LIVE, or have it invoke
> > the new RPC call & fallback to the old RPC call if it gets an error
> > indicating the new one doesn't exist.
> >
>
> Do you prefer the latter option? After a quick look, I didn't spot any
> existing compatibility code in the remote driver client. The first
> option might be slightly better wrt maintenance.
Yes, the first option is certainly simpler / clearer code todo, so lets
just do that first. We can easily revisit adding compat code in the
remote driver client at a later date if we find it to be neccessary.
Daniel
--
|: Red Hat, Engineering, London -o- http://people.redhat.com/berrange/ :|
|: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :|
|: http://autobuild.org -o- http://search.cpan.org/~danberr/ :|
|: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|
--
libvir-list mailing list
libvir-list@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/libvir-list