Am 28.05.2013 um 11:48 hat Paolo Bonzini geschrieben: > Il 28/05/2013 11:36, Kevin Wolf ha scritto: > > Am 28.05.2013 um 11:24 hat Paolo Bonzini geschrieben: > >> Il 28/05/2013 11:18, Kevin Wolf ha scritto: > >>>>> The other part why I haven't sent a fix yet is that I don't have a test > >>>>> case for it. > >>>> > >>>> Temporarily add a sleep(31) in qemu_fdatasync()? > >>>> > >>>> I was lazy in testing with -snapshot to not corrupt my disk image, which > >>>> would not trigger the same issue since qcow2-backed AFAIU. > >>>> > >>>>> I guess I need to extend blkdebug first before this can be > >>>>> reliably tested by qtest. > >>>> > >>>> It can't, since it's not a pure device emulation issue but depends on > >>>> the relative timing of filesystem operations and subsequent commands. > >>> > >>> That's why you need to take influence on the timing. It's no excuse for > >>> merging without a test case. If we only ever tested devices that have no > >>> relation to the outside world, our testing would be pretty useless and > >>> always stay as bad as it is today in many areas. > >> > >> I don't think the qtest would be timing dependent. The Linux testcase > >> is timing dependent, but for the qtest all you need to check is "is BUSY > >> set during a flush?". This can be done with blkdebug suspend/resume, > >> except that there is no way to call bdrv_debug_resume from QEMU. > > > > That's exactly what I was talking about, suspending a request is taking > > influence on its timing. I'm looking into this right now. (And it's not > > just resume, bdrv_debug_suspend can't be called from QEMU either) > > It can be called from the rules file though, can't it?
No, you can only define ACTION_INJECT_ERROR and ACTION_SET_STATE from the config file, but not ACTION_SUSPEND. Maybe we should add it, but it would still require a manual resume. So far all test cases suspend requests with explicit qemu-io commands. > > In fact, I'm checking whether we can have a monitor command to issue > > qemu-io commands, which will be more generally useful for test cases. We > > just need to make obvious that it doesn't become an ABI. Maybe prefix it > > with "__org.qemu.debug-" or something like that. > > Makes sense. I'm not sure why you'd want to read or write from > testcases, but bdrv_drain(_all) can also be useful from testcases. I imagine writing could be very useful for block job test cases. Kevin
