Using 3.0.26a, I was unable to delete a file with mode 0400 through a SMB mount. I do have "delete readonly" set. I tracked this down to nttrans.c:reply_ntcreate_and_X() where there is a readonly test to determine whether can_delete_file_in_directory() is called or not. Unfortunately, there is no lp_delete_readonly check to disable the readonly test.
Created attachment 2962 [details] Fix for deleting readonly files Here is a patch that works for me.
Applied for 3.2.0 - thanks ! Jeremy.