On Tue, Apr 09, 2024 at 10:19:09AM +0200, Lennart Poettering wrote: > All I am looking for is a very simple test that returns me a boolean: > is there kernel-level partition scanning enabled on this device or > not. And we can add a trivial sysfs attribute for that. > At this point it's not clear to me if I can write this at all in > a way that works reasonably correctly on any kernel since let's say > 4.15 (which is systemd's "recommended baseline" right now). > > I am really not sure how to salvage this mess at all. AFAICS there's > currently no way to write such a test correctly. You can't. Maybe that's a lesson to not depend on undocumented internal flags exposed by accident by a weirdo interface. Just talk to people. > I think it would be nice if the "capabilities" thing would be brought > back in a limited form. For example, if it would be changed to start > to return 0x200|0x1000 for part scanning is off, 0x1000 when it is on. > > That would then mean we return to compatibility with Linux <= 5.15, > but the new 0x1000 bit would tell us that the information is > reliable. i.e. if userspace sees 0x1000 being set we know that the > 0x200 bit is definitely correct. That would then just mean that > kernels >= 5.16 until today are left in the cold... At this point we're just better off with a clean new interface. And you can use the old hack for < 5.15 if you care strongly enough or just talk distros into backporting it to make their lives easier.
