docker volumes on cifs share cause permission disaster
The problem can be solved by using mount options that force the application of the correct user and group eventhough these attributes can't really be set on the target system its sufficient to get around the docker related problem. 

Also a reasonable set of privileges needs to be defined that is used for new files and folders.

mount -t cifs -o username=user,password=pass, \               # provide creds
  uid=www-data,forceuid,gid=root,forcegid, \                  # force gid and uid
  file_mode=744,dir_mode=744 //host/share /local/mountpoint   # set permissions for new files and directories