On Fri, May 27, 2022 at 04:50:12PM +0100, Matthew Wilcox (Oracle) wrote: > After this series, there are some places which still use it. Lots of > the converted places are trivial -- they should have been checking the > uptodate flag. The trickiest are the ones which have multiple steps > and signal "hey, something went wrong with one step in the read of this > page/folio" by setting the error flag. How many of those do we have left, and how many of those can't be changed to just return them through errors or other on-stack means? > I'm thinking about (ab)using PageChecked == PG_owner_priv_1 for this > purpose. It'd be nice to be able to use page->private for this, but > that's not always available. I know some filesystems already ascribe > a meaning to PG_owner_priv_1, but those can be distinguished by whether > the uptodate flag is set. I suspect what to do will be very ad-hoc depending on the actual user. The first priority is probably to isolate PageError so that it is only used for that kind of communication insid a single file system so that all the generic uses can go away.