From 504d81c512f614ce6aa3d4857e6587580e445a1d Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 24 Jul 2023 06:26:53 -0700 Subject: [PATCH] btrfs: don't stop integrity writeback too early commit effa24f689ce0948f68c754991a445a8d697d3a8 upstream. extent_write_cache_pages stops writing pages as soon as nr_to_write hits zero. That is the right thing for opportunistic writeback, but incorrect for data integrity writeback, which needs to ensure that no dirty pages are left in the range. Thus only stop the writeback for WB_SYNC_NONE if nr_to_write hits 0. This is a port of write_cache_pages changes in commit 05fe478dd04e ("mm: write_cache_pages integrity fix"). Note that I've only trigger the problem with other changes to the btrfs writeback code, but this condition seems worthwhile fixing anyway. CC: stable@vger.kernel.org # 4.14+ Reviewed-by: Josef Bacik Signed-off-by: Christoph Hellwig Reviewed-by: David Sterba [ updated comment ] Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/extent_io.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 58785dc7080ad..0ad69041954ff 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -3015,11 +3015,12 @@ int btree_write_cache_pages(struct address_space *mapping, } /* - * the filesystem may choose to bump up nr_to_write. + * The filesystem may choose to bump up nr_to_write. * We have to make sure to honor the new nr_to_write - * at any time + * at any time. */ - nr_to_write_done = wbc->nr_to_write <= 0; + nr_to_write_done = (wbc->sync_mode == WB_SYNC_NONE && + wbc->nr_to_write <= 0); } pagevec_release(&pvec); cond_resched();