On Mon, Aug 19, 2024 at 05:08:04PM +0200, Christoph Hellwig wrote: > On Mon, Aug 19, 2024 at 08:00:30AM -0700, Darrick J. Wong wrote: > > > This works. OTOH it will break again with the zoned RT subvolume > > > which can't support FITRIM even on devices that claim it. And for > > > actual users that care (and not just xfstests) these kinds of hacks > > > don't seem very palatable.. > > > > What does discard do on a zoned device? Is that how you reset the write > > pointer? And does that mean that either you tell the device to discard > > everything it's written in a zone, or it will do nothing? > > On an actual zone device it will probably do nothing. But at least for > NVMe the command used to implement discard is mandatory, so all > devices will show support. We also support the zoned mode on > conventional devices, but instead of through FITRIM we want to issue > it instad of a zone reset when the whole rtg has been garbage collected. > > > Hmm. No manpage for FITRIM. Why don't we return the number of bytes > > in the space map that we iterated as range.len? Or perhaps leave it > > unchanged? > > The above would seem sensible. Not sure if we can still pull it > off, though. It seems to have survived testing on TOT overnight, so I'll bake it into djwong-dev when I go through and remove the rtgroups/rtsb feature bits today. And I guess the rtgroups xarray conversion too. --D
