From patchwork Sun Jan 8 19:40:26 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andreas Gruenbacher X-Patchwork-Id: 13092671 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 68D18C54EBD for ; Sun, 8 Jan 2023 19:42:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233243AbjAHTmT (ORCPT ); Sun, 8 Jan 2023 14:42:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49538 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233542AbjAHTmR (ORCPT ); Sun, 8 Jan 2023 14:42:17 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5C38E1A8 for ; Sun, 8 Jan 2023 11:40:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1673206848; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=PT14zPx5a4QI1wKUmKAWzmL+FBkRZkQR/RJK9Bzk7iQ=; b=SXMH6XGdiiMhwcNRz9JP5GnkbHlQ1daAlrMdueG3X86G8FrK/413AZPgT/ODQR9iXzE43T X05TFCyuAJ8in9jhY8DeVxMX+NPFkeqVymSunc5fXBUo/hTXuffYOKS10zgikq7K1sSwy2 hP+m1h8lVYnR/+m0mL7teO5R8eKH5v4= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-172-j_dXx1AtPbeHu5kMaZbABw-1; Sun, 08 Jan 2023 14:40:44 -0500 X-MC-Unique: j_dXx1AtPbeHu5kMaZbABw-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id E6320101A52E; Sun, 8 Jan 2023 19:40:43 +0000 (UTC) Received: from pasta.redhat.com (ovpn-192-3.brq.redhat.com [10.40.192.3]) by smtp.corp.redhat.com (Postfix) with ESMTP id 28C01492B06; Sun, 8 Jan 2023 19:40:40 +0000 (UTC) From: Andreas Gruenbacher To: Christoph Hellwig , "Darrick J . Wong" , Alexander Viro , Matthew Wilcox Cc: Andreas Gruenbacher , linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, cluster-devel@redhat.com, Christoph Hellwig Subject: [RFC v6 02/10] iomap/gfs2: Unlock and put folio in page_done handler Date: Sun, 8 Jan 2023 20:40:26 +0100 Message-Id: <20230108194034.1444764-3-agruenba@redhat.com> In-Reply-To: <20230108194034.1444764-1-agruenba@redhat.com> References: <20230108194034.1444764-1-agruenba@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org When an iomap defines a ->page_done() handler in its page_ops, delegate unlocking the folio and putting the folio reference to that handler. This allows to fix a race between journaled data writes and folio writeback in gfs2: before this change, gfs2_iomap_page_done() was called after unlocking the folio, so writeback could start writing back the folio's buffers before they could be marked for writing to the journal. Also, try_to_free_buffers() could free the buffers before gfs2_iomap_page_done() was done adding the buffers to the current current transaction. With this change, gfs2_iomap_page_done() adds the buffers to the current transaction while the folio is still locked, so the problems described above can no longer occur. The only current user of ->page_done() is gfs2, so other filesystems are not affected. To catch out any out-of-tree users, switch from a page to a folio in ->page_done(). Signed-off-by: Andreas Gruenbacher Reviewed-by: Darrick J. Wong Reviewed-by: Christoph Hellwig --- fs/gfs2/bmap.c | 15 ++++++++++++--- fs/iomap/buffered-io.c | 8 ++++---- include/linux/iomap.h | 7 ++++--- 3 files changed, 20 insertions(+), 10 deletions(-) diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c index e7537fd305dd..46206286ad42 100644 --- a/fs/gfs2/bmap.c +++ b/fs/gfs2/bmap.c @@ -968,14 +968,23 @@ static int gfs2_iomap_page_prepare(struct inode *inode, loff_t pos, } static void gfs2_iomap_page_done(struct inode *inode, loff_t pos, - unsigned copied, struct page *page) + unsigned copied, struct folio *folio) { struct gfs2_trans *tr = current->journal_info; struct gfs2_inode *ip = GFS2_I(inode); struct gfs2_sbd *sdp = GFS2_SB(inode); - if (page && !gfs2_is_stuffed(ip)) - gfs2_page_add_databufs(ip, page, offset_in_page(pos), copied); + if (!folio) { + gfs2_trans_end(sdp); + return; + } + + if (!gfs2_is_stuffed(ip)) + gfs2_page_add_databufs(ip, &folio->page, offset_in_page(pos), + copied); + + folio_unlock(folio); + folio_put(folio); if (tr->tr_num_buf_new) __mark_inode_dirty(inode, I_DIRTY_DATASYNC); diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index c045689b6af8..a9082078e4ed 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -580,12 +580,12 @@ static void __iomap_put_folio(struct iomap_iter *iter, loff_t pos, size_t ret, { const struct iomap_page_ops *page_ops = iter->iomap.page_ops; - if (folio) + if (page_ops && page_ops->page_done) { + page_ops->page_done(iter->inode, pos, ret, folio); + } else if (folio) { folio_unlock(folio); - if (page_ops && page_ops->page_done) - page_ops->page_done(iter->inode, pos, ret, &folio->page); - if (folio) folio_put(folio); + } } static int iomap_write_begin_inline(const struct iomap_iter *iter, diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 0983dfc9a203..743e2a909162 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -131,13 +131,14 @@ static inline bool iomap_inline_data_valid(const struct iomap *iomap) * associated with them. * * When page_prepare succeeds, page_done will always be called to do any - * cleanup work necessary. In that page_done call, @page will be NULL if the - * associated page could not be obtained. + * cleanup work necessary. In that page_done call, @folio will be NULL if the + * associated folio could not be obtained. When folio is not NULL, page_done + * is responsible for unlocking and putting the folio. */ struct iomap_page_ops { int (*page_prepare)(struct inode *inode, loff_t pos, unsigned len); void (*page_done)(struct inode *inode, loff_t pos, unsigned copied, - struct page *page); + struct folio *folio); /* * Check that the cached iomap still maps correctly to the filesystem's