Re: [libvirt] [PATCH RFC 30/40] backup: Introduce virDomainBackup APIs

From: Eric Blake <eblake(a)redhat.com&gt; Introduce a few new public APIs related to incremental backups. This builds on the previous notion of a checkpoint (without an existing checkpoint, the new API is a full backup, differing from virDomainBlockCopy in the point of time chosen and in operation on multiple disks at once); and also allows creation of a new checkpoint at the same time as starting the backup (after all, an incremental backup is only useful if it covers the state since the previous backup). A backup job also affects filtering a listing of domains, as well as adding event reporting for signaling when a push model backup completes (where the hypervisor creates the backup); note that the pull model does not have an event (starting the backup lets a third party access the data, and only the third party knows when it is finished). Since multiple backup jobs can be run in parallel in the future (well, qemu doesn't support it yet, but we don't want to preclude the idea), virDomainBackupBegin() returns a positive job id, and the id is also visible in the backup XML. But until a future libvirt release adds a bunch of APIs related to parallel job management where job ids will actually matter, the documentation is also clear that job id 0 means the 'currently running backup job' (provided one exists), for use in virDomainBackupGetXMLDesc() and virDomainBackupEnd(). The full list of new APIs: virDomainBackupBegin; virDomainBackupEnd; virDomainBackupGetXMLDesc; Signed-off-by: Eric Blake <eblake(a)redhat.com&gt; Reviewed-by: Daniel P. Berrangé <berrange(a)redhat.com&gt; --- include/libvirt/libvirt-domain.h | 26 ++++- src/driver-hypervisor.h | 20 ++++ src/libvirt-domain-checkpoint.c | 7 +- src/libvirt-domain.c | 191 +++++++++++++++++++++++++++++++ src/libvirt_public.syms | 8 ++ tools/virsh-domain.c | 4 +- 6 files changed, 252 insertions(+), 4 deletions(-) diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h index 22277b0a84..2d9f69f7d4 100644 --- a/include/libvirt/libvirt-domain.h +++ b/include/libvirt/libvirt-domain.h @@ -3267,6 +3267,7 @@ typedef enum {

+/** + * VIR_DOMAIN_JOB_ID: + * + * virDomainGetJobStats field: the id of the job (so far, only for jobs + * started by virDomainBackupBegin()), as VIR_TYPED_PARAM_INT. + */ +# define VIR_DOMAIN_JOB_ID "id" + /** * VIR_DOMAIN_JOB_TIME_ELAPSED: * @@ -4106,7 +4115,8 @@ typedef void (*virConnectDomainEventMigrationIterationCallback)(virConnectPtr co * @nparams: size of the params array * @opaque: application specific data * - * This callback occurs when a job (such as migration) running on the domain + * This callback occurs when a job (such as migration or push-model + * virDomainBackupBegin()) running on the domain * is completed. The params array will contain statistics of the just completed * job as virDomainGetJobStats would return. The callback must not free @params * (the array will be freed once the callback finishes). @@ -4916,4 +4926,18 @@ int virDomainGetGuestInfo(virDomainPtr domain, int *nparams, unsigned int flags); + +int virDomainBackupBegin(virDomainPtr domain, + const char *backupXML, + const char *checkpointXML, + unsigned int flags); + +char *virDomainBackupGetXMLDesc(virDomainPtr domain, + int id, + unsigned int flags); + +int virDomainBackupEnd(virDomainPtr domain, + int id, + unsigned int flags);