Hi Dave, Darrick, Thanks for good suggestions! As my understanding, we could modify do_fchownat() to change project ID instead of group id if AT_FCHOWN_PROJID(new flags) passed in. Besides that we also need a new flag AT_FCHOWN_PROJ_INHERIT. to set/clear inherit attributes? And for Project Get, we might need extend 'struct attr {' to include project id. What do you think? Thanks, Shilong