@maartenvanveen As you mentioned in the other post @ "Cloudstor" volume plugin missing this is indeed a side effect of CIFS. As mentioned in https://www.samba.org/samba/docs/man/manpages-3/mount.cifs.8.html
The core CIFS protocol does not provide unix ownership information or mode for files and directories. Because of this, files and directories will generally appear to be owned by whatever values the uid= or gid= options are set, and will have permissions set to the default file_mode and dir_mode for the mount. Attempting to change these values via chmod/chown will return success but have no effect.
One thing we can do is pop up the uid and gid parameters (used during CIFS mount) as options to admins that you can specify as part of the volume/service creation commandlines. Do you think that will satisfy the requirement somewhat?