On Fri, Feb 24, 2023 at 12:14 PM David Howells <dhowells@xxxxxxxxxx> wrote: > > Then why do we have to wait for PG_writeback to complete? At least for PG_writeback, it's about "the _previous_ dirty write is still under way, but - since PG_dirty is set again - the page has been dirtied since". So we have to start _another_ writeback, because while the current writeback *might* have written the updated data, that is not at all certain or clear. I'm not sure what the fscache rules are. Linus