Re: [Qemu-block] [PATCH v3] qemu-img: Check for backing image if specified during create

[John Snow]

On 05/11/2017 11:17 AM, Eric Blake wrote:
> On 05/11/2017 10:11 AM, John Snow wrote:
>> Or, rather, force the open of a backing image if one was specified
>> for creation. Using a similar -unsafe option as rebase, allow qemu-img
>> to ignore the backing file validation if possible.
>>
>> It may not always be possible, as in the existing case when a filesize
>> for the new image was not specified.
>>
>> This is accomplished by shifting around the conditionals in
>> bdrv_img_create, such that a backing file is always opened unless we
>> provide BDRV_O_NO_BACKING. qemu-img is adjusted to pass this new flag
>> when -u is provided to create.
>>
>> Sorry for the heinous looking diffstat, but it's mostly whitespace.
>>
>> Inspired by: https://bugzilla.redhat.com/show_bug.cgi?id=1213786
>>
>> Signed-off-by: John Snow <address@hidden>
>> ---
>> v3: Rebased
>>
> 
>> +++ b/qemu-img.c
>> @@ -145,9 +145,11 @@ static void QEMU_NORETURN help(void)
>>             "  'snapshot_id_or_name' is deprecated, use 'snapshot_param'\n"
>>             "    instead\n"
>>             "  '-c' indicates that target image must be compressed (qcow 
>> format only)\n"
>> -           "  '-u' enables unsafe rebasing. It is assumed that old and new 
>> backing file\n"
>> -           "       match exactly. The image doesn't need a working backing 
>> file before\n"
>> -           "       rebasing in this case (useful for renaming the backing 
>> file)\n"
>> +           "  '-u' allows unsafe backing chains. For rebasing, it is 
>> assumed that old and new\n"
>> +           "       backing file match exactly. The image doesn't need a 
>> working backing file\n"
>> +           "       before rebasing in this case (useful for renaming the 
>> backing file)\n"
>> +           "       For image creation, allow creating without attempting to"
>> +           "       open the backing file.\n"
> 
> You forgot to fix my v2 review comments ('.', \n)
> 

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