On Wed, Oct 14, 2020 at 06:26:34PM +0100, Matthew Wilcox wrote: > On Wed, Oct 14, 2020 at 09:33:47AM -0700, Darrick J. Wong wrote: > > > @@ -1415,7 +1420,6 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc, > > > */ > > > if (wpc->ops->discard_page) > > > wpc->ops->discard_page(page); > > > - ClearPageUptodate(page); > > > > Er, I don't get it -- why do we now leave the page up to date after > > writeback fails? > > The page is still uptodate -- every byte in this page is at least as new > as the corresponding bytes on disk. > That seems rather odd if the preceding ->discard_page() turned an underlying delalloc block into a hole. Technically the original written data is still in the page, but it's no longer allocated/mapped or dirty so really no longer in sync with on-disk state. Hm? Brian
