Re: [PATCH v2 1/2] block: Explicit null-co uses 'read-zeroes=false'

From: Eric Blake <eblake@redhat.com>
To: "Philippe Mathieu-Daudé" <philmd@redhat.com>, qemu-devel@nongnu.org
Cc: Fam Zheng <fam@euphon.net>, Laurent Vivier <lvivier@redhat.com>,
	Thomas Huth <thuth@redhat.com>,
	qemu-block@nongnu.org, Markus Armbruster <armbru@redhat.com>,
	Wainer dos Santos Moschetta <wainersm@redhat.com>,
	Max Reitz <mreitz@redhat.com>, Alexander Bulekov <alxndr@bu.edu>,
	Bandan Das <bsd@redhat.com>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	Cleber Rosa <crosa@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Kevin Wolf <kwolf@redhat.com>
Subject: Re: [PATCH v2 1/2] block: Explicit null-co uses 'read-zeroes=false'
Date: Fri, 12 Feb 2021 13:06:19 -0600	[thread overview]
Message-ID: <5f9277ec-2f3c-8238-358b-0ab177491a2a@redhat.com> (raw)
In-Reply-To: <20210211142656.3818078-2-philmd@redhat.com>

On 2/11/21 8:26 AM, Philippe Mathieu-Daudé wrote:
> We are going to switch the 'null-co' default 'read-zeroes' value
> from FALSE to TRUE in the next commit. First explicit the FALSE
> value when it is not set.
> 
> Suggested-by: Eric Blake <eblake@redhat.com>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---

> +++ b/tests/qemu-iotests/300
> @@ -44,12 +44,12 @@ class TestDirtyBitmapMigration(iotests.QMPTestCase):
>      def setUp(self) -> None:
>          self.vm_a = iotests.VM(path_suffix='-a')
>          self.vm_a.add_blockdev(f'node-name={self.src_node_name},'
> -                               'driver=null-co')
> +                               'driver=null-co,read-zeroes=off')
>          self.vm_a.launch()
>  
>          self.vm_b = iotests.VM(path_suffix='-b')
>          self.vm_b.add_blockdev(f'node-name={self.dst_node_name},'
> -                               'driver=null-co')
> +                               'driver=null-co,read-zeroes=off')
>          self.vm_b.add_incoming(f'unix:{mig_sock}')
>          self.vm_b.launch()
>  
> 

Incomplete: 300 has a couple more lines that look like:

tests/qemu-iotests/300-        result = self.vm_a.qmp('blockdev-add',
tests/qemu-iotests/300:
node_name='node-b', driver='null-co')
--
tests/qemu-iotests/300-        result = self.vm_b.qmp('blockdev-add',
tests/qemu-iotests/300:
node_name='node-a', driver='null-co')

that could use the same treatment (noticed while reviewing Peter's patch
to add yet more uses in that test).

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org