From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0E9AE8F5B for ; Sun, 16 Jul 2023 20:26:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 87B10C433C9; Sun, 16 Jul 2023 20:26:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1689539178; bh=OAwa4yHFrLFWnhI9AOF1MEHPvOmbJPFxZWG6pgcXj+I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=R3c+Zy9U/HEnmzxNz/rgKt41aRaoogNm5Hl94lOsoioCoUjezPsGgVnibtQur32iI eRpa/3YRclqO+4jdKrJLHe77Uwo2zRoA+TlB6G+IKejSVUxUm91PjwJzJe0h0QZcO1 06MaY+Oi2bZ+XypEzy8uiCDMPEDOtT6tVsgE+4eQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Matthew Wilcox (Oracle)" , Christoph Hellwig , Jan Kara , Dave Chinner , Andrew Morton , Sasha Levin Subject: [PATCH 6.4 715/800] writeback: account the number of pages written back Date: Sun, 16 Jul 2023 21:49:28 +0200 Message-ID: <20230716195005.725847022@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230716194949.099592437@linuxfoundation.org> References: <20230716194949.099592437@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Matthew Wilcox (Oracle) [ Upstream commit 8344a3d44be3d18671e18c4ba23bb03dd21e14ad ] 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. Dave added: : XFS is the only filesystem this would affect, right? AFAIA, nothing : else enables large folios and uses writeback through : write_cache_pages() at this point... : : In which case, I'd be surprised if much difference, if any, gets : noticed by anyone. Link: https://lkml.kernel.org/r/20230628185548.981888-1-willy@infradead.org Fixes: 793917d997df ("mm/readahead: Add large folio readahead") Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Christoph Hellwig Cc: Jan Kara Cc: Dave Chinner Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin --- mm/page-writeback.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/mm/page-writeback.c b/mm/page-writeback.c index db79439990073..6faa09f1783b3 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -2434,6 +2434,7 @@ int write_cache_pages(struct address_space *mapping, for (i = 0; i < nr_folios; i++) { struct folio *folio = fbatch.folios[i]; + unsigned long nr; done_index = folio->index; @@ -2471,6 +2472,7 @@ int write_cache_pages(struct address_space *mapping, trace_wbc_writepage(wbc, inode_to_bdi(mapping->host)); error = writepage(folio, wbc, data); + nr = folio_nr_pages(folio); if (unlikely(error)) { /* * Handle errors according to the type of @@ -2489,8 +2491,7 @@ int write_cache_pages(struct address_space *mapping, error = 0; } else if (wbc->sync_mode != WB_SYNC_ALL) { ret = error; - done_index = folio->index + - folio_nr_pages(folio); + done_index = folio->index + nr; done = 1; break; } @@ -2504,7 +2505,8 @@ int write_cache_pages(struct address_space *mapping, * keep going until we have written all the pages * we tagged for writeback prior to entering this loop. */ - if (--wbc->nr_to_write <= 0 && + wbc->nr_to_write -= nr; + if (wbc->nr_to_write <= 0 && wbc->sync_mode == WB_SYNC_NONE) { done = 1; break; -- 2.39.2