[libvirt] [PATCH] virsh: Correctly detect inserted media in change-media command

[Michal Privoznik]

On 25.01.2016 13:45, Pavel Hrdina wrote:
> On Wed, Jan 13, 2016 at 05:39:10PM +0100, Michal Privoznik wrote:
>> https://bugzilla.redhat.com/show_bug.cgi?id=1250331
>>
>> It all works like this. The change-media command dumps domain
>> XML, finds the corresponding cdrom device we want to change media
>> in and returns it in the xmlNodePtr form. This way we don't have
>> to bother with keeping all the subelements or attributes that we
>> don't care about in the XML that is fed back to libvirt for the
>> update API.
>>
>> Now, the problem is we try to be clever here and detect if disk
>> already has a source (indicated by <source/> subelement).
>> However, bare fact that the element is there does not mean disk
>> has source. The element has some attributes and only if @file or
>> @dev is within them disk has source. Any other attribute is
>> meaningless for our purpose now. Make our clever check better.
> 
> That's not true, what about disk type='dir|volume|network'?  Those could be also
> used as cdrom or floppy.  The patch looks good, but extend it to detect all
> possible disk types.
> 

Well, the code doesn't know how to deal with those types anyway. For all
types you've pointed out we will change the disk type to file. So in the
end from a type='dir|volume|network' disk we will create type='file'. I
see no point in producing the following XML then:

<disk type='file' device='cdrom'>
  <source file='example.host.com'/>
  ...
</disk>

But that's a bigger bug to fix. Meanwhile I think we can use my
(incomplete?) fix.

Michal