Re: [Qemu-devel] [PATCH 08/21] backup: skip unallocated clusters for full mode

[Vladimir Sementsov-Ogievskiy]

24.01.2017 12:36, Fam Zheng wrote:
> On Tue, 01/24 12:18, Vladimir Sementsov-Ogievskiy wrote:
> > 24.01.2017 10:59, Fam Zheng wrote:
> > > On Fri, 12/23 17:28, Vladimir Sementsov-Ogievskiy wrote:
> > > > diff --git a/tests/qemu-iotests/055 b/tests/qemu-iotests/055
> > > > index 1d3fd04..388b7b2 100755
> > > > --- a/tests/qemu-iotests/055
> > > > +++ b/tests/qemu-iotests/055
> > > > @@ -30,6 +30,7 @@ target_img = os.path.join(iotests.test_dir, 'target.img')
> > > >    blockdev_target_img = os.path.join(iotests.test_dir, 'blockdev-target.img')
> > > >    image_len = 64 * 1024 * 1024 # MB
> > > > +pause_write = '3M'
> > > >    def setUpModule():
> > > >        qemu_img('create', '-f', iotests.imgfmt, test_img, str(image_len))
> > > > @@ -39,6 +40,7 @@ def setUpModule():
> > > >        qemu_io('-f', iotests.imgfmt, '-c', 'write -P0xd5 1M 32k', test_img)
> > > >        qemu_io('-f', iotests.imgfmt, '-c', 'write -P0xdc 32M 124k', test_img)
> > > >        qemu_io('-f', iotests.imgfmt, '-c', 'write -P0x33 67043328 64k', 
> > > > test_img)
> > > > +    qemu_io('-f', iotests.imgfmt, '-c', 'write -P0xdc 40M ' + pause_write, 
> > > > test_img)
> > > What does this iotest change do?
> > Without this backup block-job finishes before the next query to it from test
> > and test fails. This is a wide problem I suffer of on the way of backup
> > improvement and it should have better solution then adjusting amount of data
> > being copied...
> You can use blkdebug to pause I/O before querying the block job, or simply
> throttle it down.
>
> Fam

throttling down is not better I thing then just copying additional 3M, 
it is environment-dependent hack too. And we can't use throttling in all 
tests - throttling should be itself tested separately.

In the other thread there was an idea to not delete block jobs on their 
finish, but maintain them in some 'finished' state. This will be great 
for the case and will be generic.

--
Best regards,
Vladimir