From: Christoph Hellwig hch@lst.de
[ Upstream commit 7ea1d9b4a840c2dd01d1234663d4a8ef256cfe39 ]
write_cache_pages always clear the page dirty bit before calling into the file systems, and leaves folios with a writeback failure without the dirty bit after return. We also clear the per-block writeback bits for writeback failures unless no I/O has submitted, which will leave the folio in an inconsistent state where it doesn't have the folio dirty, but one or more per-block dirty bits. This seems to be due the place where the iomap_clear_range_dirty call was inserted into the existing not very clearly structured code when adding per-block dirty bit support and not actually intentional. Switch to always clearing the dirty on writeback failure.
Fixes: 4ce02c679722 ("iomap: Add per-block dirty state tracking to improve performance") Signed-off-by: Christoph Hellwig hch@lst.de Link: https://lore.kernel.org/r/20231207072710.176093-2-hch@lst.de Signed-off-by: Christian Brauner brauner@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/iomap/buffered-io.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-)
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index f72df2babe561..fc5c64712318a 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1843,16 +1843,10 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc, if (unlikely(error)) { /* * Let the filesystem know what portion of the current page - * failed to map. If the page hasn't been added to ioend, it - * won't be affected by I/O completion and we must unlock it - * now. + * failed to map. */ if (wpc->ops->discard_folio) wpc->ops->discard_folio(folio, pos); - if (!count) { - folio_unlock(folio); - goto done; - } }
/* @@ -1861,6 +1855,16 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc, * all the dirty bits in the folio here. */ iomap_clear_range_dirty(folio, 0, folio_size(folio)); + + /* + * If the page hasn't been added to the ioend, it won't be affected by + * I/O completion and we must unlock it now. + */ + if (error && !count) { + folio_unlock(folio); + goto done; + } + folio_start_writeback(folio); folio_unlock(folio);