On Thu, 7 Nov 2024 at 22:00, Jeff Layton <jlayton@xxxxxxxxxx> wrote: > + /* > + * If nothing was emitted, return to avoid setting the flag > + * and terminating the buffer. > + */ > + if (seq->count == start) > + return ret; First of all, I don't think it's okay to subtly change behavior of other string attributes in this patch. If that is what we want, it should be separated into a separate prep or followup patch. Clearing the returned mask if there's no subtype does sound like the right thing to do. But it makes it impossible to detect whether the running kernel supports returning subtype or not. Missing the STATMOUNT_FS_SUBTYPE in statmount.mask may mean two different things: - kernel supports returning subtype and filesystem does not have a subtype - kernel does not support returning a subtype and the filesystem may or may not have a subtype I think we can live with that, but it would be really good if there was a universal way to detect whether a particular feature is supported on the running kernel or not, and not have to rely on syscall specific ways. Thanks, Miklos
