Am 16.03.2017 um 01:46 hat John Snow geschrieben:
> This lets us hook into drained_begin and drained_end requests from the
> backend level, which is particularly useful for making sure that all
> jobs associated with a particular node (whether the source or the target)
> receive a drain request.
>
> Suggested-by: Kevin Wolf <kw...@redhat.com>
> Signed-off-by: John Snow <js...@redhat.com>
>
> --
>
> RFC topics:
>
> - BlkDevOps is traditionally only for Qdev devices, and a BlockJob is not
> currently a 'device'... Do we want to loosen this restriction, find another
> way to deliver callbacks to BlockJobs attached to BlkBackends, or do
> something
> crazy like make a BlockJob device object?
>
> struct JobDevice {
> DeviceState parent_obj;
> BlockJob *job;
> } ...??
We should probably rename BlkDevOps to something that works not only for
devices, but for any user of a BlockBackend. I don't think the
implementation has to be changed, it's just a struct of callbacks and an
opaque pointer that is actually properly treated as opaque.
BlockBackend also has a dev field, which is indeed supposed to be a
DeviceState and is sometimes casted to one (if we can assert
!blk->legacy_dev), but it's a concept completely separate from
BlkDevOps. So we just need to be sure not to call blk_attach_dev() or
blk_attach_dev_legacy().
Kevin
