On Thu, Nov 28, 2019 at 04:59:30PM +0100, Miklos Szeredi wrote: > String options always have parameters, hence the check for optional > parameter will never trigger. What do you mean, always have parameters? Granted, for fsconfig(2) it's (currently) true, but I see at least two other pathways that do not impose such requirement - vfs_parse_fs_string() and rbd_parse_options(). You seem to deal with the former later in the patchset, but I don't see anything for the latter...