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 0D18A140796; Tue, 23 Jan 2024 01:07:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705972052; cv=none; b=ahfruicsbMJiCkBGyDHu++MipCoxfozZm3QUo2HGXlYqh5SEGWNqTIWmL3Cg5jrnXvOkMvkXWwZy3nmE2E6RIPFFZDjTpzapL1+e2S9zItsaDYMhWwthipUoVtwbHeyl8UW8wZ1YBaatSl+q6yW41UZAQ+91Lg7OoKO5AW/fie0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705972052; c=relaxed/simple; bh=pr27Fg5X1C4QRnFmzTmdK5JQjK3E20QHe0Zl1MsnssY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RhRgEG9XUQRuk0H0jduBeehL0gH6z9gxa92EMuYsO1aNiqhQu2+O7wexUTqfyBEh8+oiv5eNLxGkAh6BomFlqsMiW8Rt6ftOwUcv3nGiSpTNv9oyCBo3c9tnt2+o7Ay4fNkYUnbgOhwPlDi0d2PZ2pBFUhc9PYgoueB86nX5aSk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=0634L1/y; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="0634L1/y" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BCAACC433F1; Tue, 23 Jan 2024 01:07:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1705972051; bh=pr27Fg5X1C4QRnFmzTmdK5JQjK3E20QHe0Zl1MsnssY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0634L1/yCR60l6JCiZBADgVmxksCkb31G7ThkghGV2QlSpIi03i+kHj/VGfYjkd9X fHniXpWmPuqENxOrq2rDDJ7oiR1MxwijrVZLGxkwxw9YezL8M3Wk9XWr6tSboe7V9b FEH5T4yqVgPKJzTrOxmu5Z9zVUyL9CPHrRk/zDZ0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Matthew Wilcox (Oracle)" , Jens Axboe Subject: [PATCH 6.1 416/417] block: Remove special-casing of compound pages Date: Mon, 22 Jan 2024 15:59:44 -0800 Message-ID: <20240122235806.104877332@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240122235751.480367507@linuxfoundation.org> References: <20240122235751.480367507@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Matthew Wilcox (Oracle) commit 1b151e2435fc3a9b10c8946c6aebe9f3e1938c55 upstream. The special casing was originally added in pre-git history; reproducing the commit log here: > commit a318a92567d77 > Author: Andrew Morton > Date: Sun Sep 21 01:42:22 2003 -0700 > > [PATCH] Speed up direct-io hugetlbpage handling > > This patch short-circuits all the direct-io page dirtying logic for > higher-order pages. Without this, we pointlessly bounce BIOs up to > keventd all the time. In the last twenty years, compound pages have become used for more than just hugetlb. Rewrite these functions to operate on folios instead of pages and remove the special case for hugetlbfs; I don't think it's needed any more (and if it is, we can put it back in as a call to folio_test_hugetlb()). This was found by inspection; as far as I can tell, this bug can lead to pages used as the destination of a direct I/O read not being marked as dirty. If those pages are then reclaimed by the MM without being dirtied for some other reason, they won't be written out. Then when they're faulted back in, they will not contain the data they should. It'll take a pretty unusual setup to produce this problem with several races all going the wrong way. This problem predates the folio work; it could for example have been triggered by mmaping a THP in tmpfs and using that as the target of an O_DIRECT read. Fixes: 800d8c63b2e98 ("shmem: add huge pages support") Cc: Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- block/bio.c | 38 +++++++++++++++++++++++--------------- 1 file changed, 23 insertions(+), 15 deletions(-) --- a/block/bio.c +++ b/block/bio.c @@ -1109,13 +1109,22 @@ bool bio_add_folio(struct bio *bio, stru void __bio_release_pages(struct bio *bio, bool mark_dirty) { - struct bvec_iter_all iter_all; - struct bio_vec *bvec; + struct folio_iter fi; - bio_for_each_segment_all(bvec, bio, iter_all) { - if (mark_dirty && !PageCompound(bvec->bv_page)) - set_page_dirty_lock(bvec->bv_page); - put_page(bvec->bv_page); + bio_for_each_folio_all(fi, bio) { + struct page *page; + size_t done = 0; + + if (mark_dirty) { + folio_lock(fi.folio); + folio_mark_dirty(fi.folio); + folio_unlock(fi.folio); + } + page = folio_page(fi.folio, fi.offset / PAGE_SIZE); + do { + folio_put(fi.folio); + done += PAGE_SIZE; + } while (done < fi.length); } } EXPORT_SYMBOL_GPL(__bio_release_pages); @@ -1414,12 +1423,12 @@ EXPORT_SYMBOL(bio_free_pages); */ void bio_set_pages_dirty(struct bio *bio) { - struct bio_vec *bvec; - struct bvec_iter_all iter_all; + struct folio_iter fi; - bio_for_each_segment_all(bvec, bio, iter_all) { - if (!PageCompound(bvec->bv_page)) - set_page_dirty_lock(bvec->bv_page); + bio_for_each_folio_all(fi, bio) { + folio_lock(fi.folio); + folio_mark_dirty(fi.folio); + folio_unlock(fi.folio); } } @@ -1462,12 +1471,11 @@ static void bio_dirty_fn(struct work_str void bio_check_pages_dirty(struct bio *bio) { - struct bio_vec *bvec; + struct folio_iter fi; unsigned long flags; - struct bvec_iter_all iter_all; - bio_for_each_segment_all(bvec, bio, iter_all) { - if (!PageDirty(bvec->bv_page) && !PageCompound(bvec->bv_page)) + bio_for_each_folio_all(fi, bio) { + if (!folio_test_dirty(fi.folio)) goto defer; }