'reference existing' files showing as downloaded from original entity not currently the attached entity

Issue Summary

I'm in the process of upgrading the download_count module to d7, and the meta data tracked for file downloads includes the entity from which the file was downloaded. The problem is, 'reference existing' files are reporting the original entity to which they are attached instead of the current entity.

From what I can see it's because the _filefield_sources_field_access function doesn't include the entity in its field_access call. I'm trying to come up with a patch, but any pointers/suggestions would be very welcome (i'm still finding my way around the file api in d7).

Thanks.