On Fri, Jun 02, 2023 at 11:24:40PM +0100, Matthew Wilcox (Oracle) wrote: > The check for the folio being under writeback is unnecessary; the caller > has checked this and the folio is locked, so the folio cannot be under > writeback at this point. Do we need a debug assertion here to validate that filemap_release_folio has already filtered out folios unergoing writeback? The documentation change in the next patch might be fine since you're the pagecache maintainer. > The comment is somewhat misleading in that it talks about one specific > situation in which we can see a dirty folio. There are others, so change > the comment to explain why we can't release the iomap_page. > > Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> > --- > fs/iomap/buffered-io.c | 8 +++----- > 1 file changed, 3 insertions(+), 5 deletions(-) > > diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c > index 08ee293c4117..2054b85c9d9b 100644 > --- a/fs/iomap/buffered-io.c > +++ b/fs/iomap/buffered-io.c > @@ -483,12 +483,10 @@ bool iomap_release_folio(struct folio *folio, gfp_t gfp_flags) > folio_size(folio)); > > /* > - * mm accommodates an old ext3 case where clean folios might > - * not have had the dirty bit cleared. Thus, it can send actual > - * dirty folios to ->release_folio() via shrink_active_list(); > - * skip those here. > + * If the folio is dirty, we refuse to release our metadata because > + * it may be partially dirty (FIXME, add a test for that). Er... is this FIXME reflective of incomplete code? --D > */ > - if (folio_test_dirty(folio) || folio_test_writeback(folio)) > + if (folio_test_dirty(folio)) > return false; > iomap_page_release(folio); > return true; > -- > 2.39.2 >
