On 10/23/2014 08:56 AM, Max Reitz wrote: > Sometimes, qemu does not have a filename to work with (it then generates > a JSON filename), so it does not know which directory to use for a > backing file specified by a relative filename. > > In this case, qemu should not somehow try to append the backing file's > name to the JSON object, but rather just print an error and bail out.
Hmm. Makes me wonder if we should extend BlockdevOptions to allow for a
BDS to additionally track a notion of "current directory" from which any
relative names should be interpreted against. That is, something like:
TEST_IMG="json:{
'driver': '$IMGFMT',
'file': {
'driver': 'blkdebug',
'image': {
'driver': 'file',
'filename': '$TEST_IMG'
},
+ 'rel-dir': '$DIR_OF_TEST_IMG_BACK',
'set-state': [
{
'event': 'read_aio',
'new_state': 42
}
]
}
}" _img_info | _filter_img_info
being a way to let us access the (otherwise relative-only) backing file
encoded behind the blkdebug wall with a notion of the correct directory
to find it in. Of course, such an extension to BDS description (for
both command line and QMP) would be a separate series...
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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