Darrick, On Tue, Jun 29, 2021 at 7:47 AM Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote: > On Mon, Jun 28, 2021 at 10:59:55PM +0100, Matthew Wilcox wrote: > > > > so permit pages without an iop to enter writeback and create an iop > > > > *then*. Would that solve your problem? > > > > > > It is the right thing to do, especially when combined with a feature > > > patch to not bother to create the iomap_page structure on small > > > block size file systems when the extent covers the whole page. > > > > We don't know the extent layout at the point where *this* patch creates > > iomap_pages during writeback. I imagine we can delay creating one until > > we find out what our destination layout will be? > > Hmm. Actually ->page_mkwrite is always is always called on an uptodate > page and we even assert that. I should have remembered the whole page > fault path better. > > So yeah, I think we should take patch 1 from Andreas, then a non-folio > version of your patch as a start. will you pick up those two patches and push them to Linus? They both seem pretty safe. Thanks, Andreas
