On Mon, 05/15 12:02, Peter Lieven wrote:
Hi Block developers,
I would like to add a feature to Qemu to drain all traffic from a block so that
I can take external snaphosts without the risk to that in the middle of a write
operation. Its meant for cases where where QGA freeze/thaw is not available.
For me its enough to have this through qemu-io, but Kevin asked me to check
if its not worth to have a stable API for it and present it via QMP/HMP.
What are your thoughts?
For debugging purpose or a "hacky" usage where you know what you are doing, it
may be fine to have this. The only issue is it should be a separate flag, like
BlockJob.user_paused.
What happens from guest perspective? In the case of virtio, the request queue is
not handled and -ETIMEDOUT may happen. With IDE, I/O commands are still handled,
the command is not effective (or rather the implementation is not complete).