Re: [Qemu-devel] [PATCH v3 2/4] block: Add 'ignore-backing' field to BlockdevOptionsGenericCOWFormat

[Max Reitz <mreitz@redhat.com>]

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On 11.09.2015 19:28, Kevin Wolf wrote:
> Am 11.09.2015 um 19:21 hat Max Reitz geschrieben:
>> On 10.09.2015 15:39, Alberto Garcia wrote:
>>> If set to true, the image will be opened with the BDRV_O_NO_BACKING
>>> flag. This is useful for creating snapshots using images opened with
>>> blockdev-add, since they are not supposed to have a backing image
>>> before the operation.
>>>
>>> Signed-off-by: Alberto Garcia <berto@igalia.com>
>>> ---
>>>  block.c              | 5 +++++
>>>  qapi/block-core.json | 6 +++++-
>>>  2 files changed, 10 insertions(+), 1 deletion(-)
>>
>> Ignorant of any possible previous discussion that might have taken
>> place: The documentation for @backing says it may be set to the empty
>> string in order to achieve exactly that.
>>
>> So why do we need the new flag? Because "backing: ''" is ugly?
> 
> I guess it's just because you're the only one who actually reads the
> documentation. When discussing this, I didn't remember that we already
> had a way to express this (an additional bool wouldn't have been my
> favourite solution anyway). Thanks for catching this.

I read the patch, it was part of the context. ;-)

Max


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