Re: flatview_write_continue global mutex deadlock

[Paolo Bonzini]

On 03/09/20 17:42, Vladimir Sementsov-Ogievskiy wrote:
> 
> 
> so no timer exists now: reconnect code goes to yield during drain, to
> continue after drain-end.. Haha, that's obviously bad design, as nobody
> will wake up the waiting requests, and drain will hang forever. OK
> thanks, you helped me, I see now that nbd code is wrong..
> 
> But still, is it OK to do blk_drain holding the global mutex? Drain may
> take a relatively long time, and vm is not responding due to global
> mutex locked in cpu thread..

It has been like that forever, and it's a major reason to use iothreads
even if you don't care about performance.

Paolo