Django image upload failed when not enough disk space with unrelated exception

[Yang Youseok]

Currently, when horizon use direct file upload for glance image upload and horizon server does not enough disk space for temporary file, horizon meets 'KeyError' for 'visibility'.

I think root cause of comment 31 in https://bugzilla.redhat.com/show_bug.cgi?id=1508725 is same as what I saw.

Master version of horizon allow empty params of 'visibility' so I guess master will have something different exception though, I think root problem is still valid in master too.

Root cause I assume is that

- When request.POST is accessed (openstack_dashboard/api/rest/utils.py post2data())
- Django multipartpaser start to parse
- It does not emit any exception when IOError(No disk space) occurred only with error hint which is emtpy POST dict.
- request.DATA is empty dict {} since request.POST is emtpy.
- [Bug here] Logic access request.DATA is all invalid since this dict is empty. (Actually from my environment, Ocata, 'visibility' key is first location that I find KeyError.)

Sugguestion

- Raise some exception when Django request.POST is empty when we assume it's filled with multipart data.

I'm not 100% sure since it's just result of only the phenomenon, so please correct me what i'm missing if there.

Thanks