[libvirt] [PATCH v3 4/4] on_missing: Emit event on disk source dropping

[Daniel P. Berrange]

On Wed, Oct 19, 2011 at 04:42:59PM +0200, Michal Privoznik wrote:
> If a disk source gets dropped because it is not accessible,
> mgmt application might want to be informed about this. Therefore
> we need to emit an event. The event presented in this patch
> is however a bit superset of what written above. The reason is simple:
> an intention to be easily expanded, e.g. on 'user ejected disk
> in guest' events. Therefore, callback gets target string
> (which should be unique among a domain) and reason (an integer);
> It can't get alias, as some disk changes (esp. dropping source
> caused by on_missing feature) might happen on inactive domain
> where no disks aliases exists.
> ---
>  daemon/remote.c                                    |   37 ++++++++++++++
>  examples/domain-events/events-c/event-test.c       |   27 ++++++++++-
>  examples/domain-events/events-python/event-test.py |    4 ++
>  include/libvirt/libvirt.h.in                       |   28 +++++++++++
>  python/libvirt-override-virConnect.py              |    9 ++++
>  python/libvirt-override.c                          |   51 ++++++++++++++++++++
>  src/conf/domain_event.c                            |   50 +++++++++++++++++++
>  src/conf/domain_event.h                            |    7 +++
>  src/libvirt_private.syms                           |    2 +
>  src/qemu/qemu_domain.c                             |    7 +++
>  src/remote/remote_driver.c                         |   34 +++++++++++++
>  src/remote/remote_protocol.x                       |    9 +++-
>  src/remote_protocol-structs                        |    5 ++
>  13 files changed, 268 insertions(+), 2 deletions(-)
> diff --git a/include/libvirt/libvirt.h.in b/include/libvirt/libvirt.h.in
> index 361881a..d6d928a 100644
> --- a/include/libvirt/libvirt.h.in
> +++ b/include/libvirt/libvirt.h.in
> @@ -2996,6 +2996,33 @@ typedef void (*virConnectDomainEventBlockJobCallback)(virConnectPtr conn,
>                                                        void *opaque);
>  
>  /**
> + * virConnectDomainEventDiskEjectReason:
> + *
> + * The reason describing why this callback is called
> + */
> +typedef enum {
> +    VIR_DOMAIN_DISK_EJECT_ON_MISSING = 0,
> +} virConnectDomainEventDiskEjectReason;

I'd name this:

 VIR_DOMAIN_DISK_EJECT_MISSING_ON_START


> +
> +/**
> + * virConnectDomainEventDiskEjectCallback:
> + * @conn: connection object
> + * @dom: domain on which the event occurred
> + * @target: target which changed status

In the I/O error event, we use  'srcPath' and 'devAlias' in the event
name. I think we probably ought todo the same here. So the app gets
details of which file was missing, and the unique alias of the device.

> + * @reason: reason why this callback was called; any of
> + *          virConnectDomainEventDiskEjectReason
> + * @opaque: application specified data
> + *
> + * The callback signature to use when registering for an event of type
> + * VIR_DOMAIN_EVENT_ID_IO_ERROR with virConnectDomainEventRegisterAny()
> + */
> +typedef void (*virConnectDomainEventDiskEjectCallback)(virConnectPtr conn,
> +                                                       virDomainPtr dom,
> +                                                       const char *target,
> +                                                       int reason,
> +                                                       void *opaque);
> +


Daniel
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