Re: [libvirt] [PATCH] blockjob: use stable disk string in job event

When the block job event was first added, it was for block pull, where the active layer of the disk remains the same name. It was also in a day where we only cared about local files, and so we always had a canonical absolute file name. But two things have changed since then: we now have network disks, where determining a single absolute string does not really make sense; and we have two-phase jobs (copy and active commit) where the name of the active layer changes between the first event (ready, on the old name) and second (complete, on the pivoted name). Adam Litke reported that having an unstable string between events makes life harder for clients. Furthermore, all of our API that operate on a particular disk of a domain accept multiple strings: not only the absolute name of the active layer, but also the destination device name (such as 'vda'). As this latter name is stable, even for network sources, it serves as a better string to supply in block job events. * include/libvirt/libvirt.h.in (virConnectDomainEventBlockJobCallback): Document altered semantics. * src/conf/domain_event.c (_virDomainEventBlockJob): Rename field, to ensure we catch all clients. (virDomainEventBlockJobDispose, virDomainEventBlockJobNew) (virDomainEventBlockJobNewFromObj) (virDomainEventBlockJobNewFromDom) (virDomainEventDispatchDefaultFunc): Adjust clients. * src/conf/domain_event.h: Likewise. * src/qemu/qemu_driver.c (qemuDomainBlockJobImpl): Likewise. * src/qemu/qemu_process.c (qemuProcessHandleBlockJob): Likewise. * src/remote/remote_protocol.x (remote_domain_event_block_job_msg): Likewise. * src/remote/remote_driver.c (remoteDomainBuildEventBlockJobHelper): Likewise. * daemon/remote.c (remoteRelayDomainEventBlockJob): Likewise. * src/remote_protocol-structs: Regenerate. Signed-off-by: Eric Blake <eblake(a)redhat.com&gt; --- If you think backward compatibility of old clients that expected and operated on an absolute name is too important to break, I'm open to suggestions on alternatives how to preserve that. We don't have a flag argument during event registration, or I would have used it. Otherwise, I hope this change is okay as-is.

daemon/remote.c | 8 ++++---- include/libvirt/libvirt.h.in | 11 ++++++++++- src/conf/domain_event.c | 18 +++++++++--------- src/conf/domain_event.h | 4 ++-- src/qemu/qemu_driver.c | 2 +- src/qemu/qemu_process.c | 4 +--- src/remote/remote_driver.c | 2 +- src/remote/remote_protocol.x | 2 +- src/remote_protocol-structs | 2 +- 9 files changed, 30 insertions(+), 23 deletions(-)