On Mon 24 Oct 2016 12:53:41 PM CEST, Paolo Bonzini wrote: >> My first thoughts were about how to let an unpause succeed without a >> previous pause for these objects, but actually I think this isn't >> what we should do. We rather want to actually do the pause instead >> because even new BDSes and block jobs should probably start in a >> quiesced state when created inside a drain_all section. > > Yes, I agree with this. It shouldn't be too hard to implement it. It > would require a BlockDriverState to look at the global "inside > bdrv_drain_all_begin" state, and ask its BlockBackend to disable > itself upon bdrv_replace_child.
Why in bdrv_replace_child()? bdrv_drain_all_end() enables all BDSs, but if you add one with "blockdev-add" it's not going to be disabled using this method. In addition to that block jobs need the same, don't they? Something like "job->pause_count = all_quiesce_counter" in the initialization. I think we'd also need to add block_job_pause_point() at the beginning of each one of their coroutines, in order to make sure that they really start paused. Berto
