Am 23.02.2016 um 14:54 hat Paolo Bonzini geschrieben: > > > On 23/02/2016 13:49, Fam Zheng wrote: > > On Tue, 02/23 11:43, Paolo Bonzini wrote: > >> > >> > >> On 23/02/2016 06:57, Fam Zheng wrote: > >>>>>> + qed_cancel_need_check_timer(s); > >>>>>> + qed_need_check_timer_cb(s); > >>>>>> + } > >>>>> > >>>>> What if an allocating write is queued (the else branch case)? Its > >>>>> completion > >>>>> will be in bdrv_drain and it could arm the need_check_timer which is > >>>>> wrong. > >>>>> > >>>>> We need to drain the allocating_write_reqs queue before checking the > >>>>> timer. > >>>> > >>>> You're right, but how? That's what bdrv_drain(bs) does, it's a > >>>> chicken-and-egg problem. > >>> > >>> Maybe use an aio_poll loop before the if? > >> > >> That would not change the fact that you're reimplementing bdrv_drain > >> inside bdrv_qed_drain. > > > > But it fulfills the contract of .bdrv_drain. This is the easy way, the hard > > way > > would be iterating through the allocating_write_reqs list and process reqs > > one > > by one synchronously, which still involves aio_poll indirectly. > > The easy way would be better then. > > Stefan, any second opinion?
What's the status here? It would be good to have qed not segfaulting all the time. Kevin
