On Wed, 28 Jun 2023 19:55:48 +0100 "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> wrote: > nr_to_write is a count of pages, so we need to decrease it by the number > of pages in the folio we just wrote, not by 1. Most callers specify > either LONG_MAX or 1, so are unaffected, but writeback_sb_inodes() > might end up writing 512x as many pages as it asked for. 512 is a big number, Should we backport this? > Fixes: 793917d997df ("mm/readahead: Add large folio readahead") I'm not seeing how a readahead change messed up writeback accounting?