From b1793929b7dc17842a5e4377796b005d3efd61bc Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Thu, 15 Feb 2024 07:36:42 +0100 Subject: writeback: factor folio_prepare_writeback() out of write_cache_pages() Reduce write_cache_pages() by about 30 lines; much of it is commentary, but it all bundles nicely into an obvious function. [hch@lst.de: rename should_writeback_folio to folio_prepare_writeback per Jan] Link: https://lkml.kernel.org/r/20240215063649.2164017-8-hch@lst.de Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Christoph Hellwig Reviewed-by: Brian Foster Reviewed-by: Jan Kara Acked-by: Dave Chinner Cc: Christian Brauner Cc: David Howells Signed-off-by: Andrew Morton --- mm/page-writeback.c | 61 +++++++++++++++++++++++++++++------------------------ 1 file changed, 34 insertions(+), 27 deletions(-) (limited to 'mm') diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 3a1e23bed4052..4bc55ce9597d1 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -2360,6 +2360,38 @@ void tag_pages_for_writeback(struct address_space *mapping, } EXPORT_SYMBOL(tag_pages_for_writeback); +static bool folio_prepare_writeback(struct address_space *mapping, + struct writeback_control *wbc, struct folio *folio) +{ + /* + * Folio truncated or invalidated. We can freely skip it then, + * even for data integrity operations: the folio has disappeared + * concurrently, so there could be no real expectation of this + * data integrity operation even if there is now a new, dirty + * folio at the same pagecache index. + */ + if (unlikely(folio->mapping != mapping)) + return false; + + /* + * Did somebody else write it for us? + */ + if (!folio_test_dirty(folio)) + return false; + + if (folio_test_writeback(folio)) { + if (wbc->sync_mode == WB_SYNC_NONE) + return false; + folio_wait_writeback(folio); + } + BUG_ON(folio_test_writeback(folio)); + + if (!folio_clear_dirty_for_io(folio)) + return false; + + return true; +} + /** * write_cache_pages - walk the list of dirty pages of the given address space and write all of them. * @mapping: address space structure to write @@ -2430,38 +2462,13 @@ int write_cache_pages(struct address_space *mapping, for (i = 0; i < nr_folios; i++) { folio = fbatch.folios[i]; folio_lock(folio); - - /* - * Page truncated or invalidated. We can freely skip it - * then, even for data integrity operations: the page - * has disappeared concurrently, so there could be no - * real expectation of this data integrity operation - * even if there is now a new, dirty page at the same - * pagecache address. - */ - if (unlikely(folio->mapping != mapping)) { -continue_unlock: + if (!folio_prepare_writeback(mapping, wbc, folio)) { folio_unlock(folio); continue; } - if (!folio_test_dirty(folio)) { - /* someone wrote it for us */ - goto continue_unlock; - } - - if (folio_test_writeback(folio)) { - if (wbc->sync_mode != WB_SYNC_NONE) - folio_wait_writeback(folio); - else - goto continue_unlock; - } - - BUG_ON(folio_test_writeback(folio)); - if (!folio_clear_dirty_for_io(folio)) - goto continue_unlock; - trace_wbc_writepage(wbc, inode_to_bdi(mapping->host)); + error = writepage(folio, wbc, data); wbc->nr_to_write -= folio_nr_pages(folio); -- cgit 1.2.3-korg