From patchwork Thu Dec 17 01:11:57 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yafang Shao X-Patchwork-Id: 11978875 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0CEF1C3526F for ; Thu, 17 Dec 2020 01:13:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DF025233FB for ; Thu, 17 Dec 2020 01:13:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389103AbgLQBNc (ORCPT ); Wed, 16 Dec 2020 20:13:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55116 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725871AbgLQBNc (ORCPT ); Wed, 16 Dec 2020 20:13:32 -0500 Received: from mail-vs1-xe36.google.com (mail-vs1-xe36.google.com [IPv6:2607:f8b0:4864:20::e36]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0441FC06138C; Wed, 16 Dec 2020 17:12:33 -0800 (PST) Received: by mail-vs1-xe36.google.com with SMTP id e15so12549429vsa.0; Wed, 16 Dec 2020 17:12:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=9alW6vAYyuzuIAm2W1sBzzo1XFQKdglwiDiVNpF1K2U=; b=Wi5ul+TpVrtbHopu2Iwb3DlGk1ZxVzDtLAsRdQMTu0GERUdvG2WVNpqpfK16fgUS9h yhq0822cOkKhzQ7ZRWz8Npvm048BUEnToPYJy+xnZwyVe3RDHJLz0OF/hw55IGWeldgE 5eN4vwFCW486dOUy2PHx60b2avDZZplCXBLtp/MZ7UGJPsDYcXQeO1lq3yyxiP14Ndbr c3KSA6WFYM51Cm3HJNKmNc96A2rjtwuTYDUHTxjQG6h9I+beliWreu54pMsFr24ff8cW Bl8HuQt0co6Qc5ubOg4BSBFIANtBrd9eSaTpbhD0uV6moRHkdHgfcLJJB4b+Q/X3+GZ2 HG7Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=9alW6vAYyuzuIAm2W1sBzzo1XFQKdglwiDiVNpF1K2U=; b=uFFdvix69oFsXkVgW99anWq3fTBojBLKzgr09ZQtvW7byQjFIM+Fn8u1ZRGxBNu3EB rkezMZDqUpnZ6xLcLkkeNFjmwfehkWS2Rr0Sgh7mZD0Ki+z22f+WrzdcLzXUVr74zfJy 1+acVqK5qFaPKzUYbhqsDOtFDRxmm9Nr46/IAB0Aj9pjltoiSmLIW2pOdu3JlfAqYikI 4HnxsO7zvFPo2JV+bSeSBnODuWd3urT3DHtVDGOfkTqzFygtfhA4FGt+UBWOK++eY4i3 qLG5kKZW/qJz55Fk27bJLNYHL9PqNzbbB47j9DcJwOz8gvikImevIaqmZJ5uXcGEkAAo lH6A== X-Gm-Message-State: AOAM530Pp50QnzwiQPC65yWMJh3w5EajK6BWFwvcL1vdm8D9BbgpocrN K9RQaO3xemd9ncDG50WWr7E3LBue5e/NBivF X-Google-Smtp-Source: ABdhPJymD38OIInUxz/A6UMIS832ePfAYJx4qTFdpzI+xn54beO/QqmFh11xxFmKvkJ1ebq2NwfIEA== X-Received: by 2002:a67:1142:: with SMTP id 63mr15960710vsr.24.1608167552295; Wed, 16 Dec 2020 17:12:32 -0800 (PST) Received: from localhost.localdomain ([50.236.19.102]) by smtp.gmail.com with ESMTPSA id i63sm2900760uad.4.2020.12.16.17.12.27 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 16 Dec 2020 17:12:31 -0800 (PST) From: Yafang Shao To: darrick.wong@oracle.com, willy@infradead.org, david@fromorbit.com, hch@infradead.org, mhocko@kernel.org, akpm@linux-foundation.org, dhowells@redhat.com, jlayton@redhat.com Cc: linux-fsdevel@vger.kernel.org, linux-cachefs@redhat.com, linux-xfs@vger.kernel.org, linux-mm@kvack.org, Yafang Shao , Christoph Hellwig Subject: [PATCH v13 4/4] xfs: use current->journal_info to avoid transaction reservation recursion Date: Thu, 17 Dec 2020 09:11:57 +0800 Message-Id: <20201217011157.92549-5-laoar.shao@gmail.com> X-Mailer: git-send-email 2.24.3 (Apple Git-128) In-Reply-To: <20201217011157.92549-1-laoar.shao@gmail.com> References: <20201217011157.92549-1-laoar.shao@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org PF_FSTRANS which is used to avoid transaction reservation recursion, is dropped since commit 9070733b4efa ("xfs: abstract PF_FSTRANS to PF_MEMALLOC_NOFS") and replaced by PF_MEMALLOC_NOFS which means to avoid filesystem reclaim recursion. As these two flags have different meanings, we'd better reintroduce PF_FSTRANS back. To avoid wasting the space of PF_* flags in task_struct, we can reuse the current->journal_info to do that, per Willy. As the check of transaction reservation recursion is used by XFS only, we can move the check into xfs_vm_writepage(s), per Dave. Cc: Darrick J. Wong Cc: Matthew Wilcox (Oracle) Cc: Christoph Hellwig Cc: Dave Chinner Cc: Michal Hocko Cc: David Howells Cc: Jeff Layton Signed-off-by: Yafang Shao --- fs/iomap/buffered-io.c | 7 ------- fs/xfs/xfs_aops.c | 17 +++++++++++++++++ fs/xfs/xfs_trans.h | 26 +++++++++++++++++++------- 3 files changed, 36 insertions(+), 14 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 10cc7979ce38..3c53fa6ce64d 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1458,13 +1458,6 @@ iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data) PF_MEMALLOC)) goto redirty; - /* - * Given that we do not allow direct reclaim to call us, we should - * never be called in a recursive filesystem reclaim context. - */ - if (WARN_ON_ONCE(current->flags & PF_MEMALLOC_NOFS)) - goto redirty; - /* * Is this page beyond the end of the file? * diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c index 2371187b7615..0da0242d42c3 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -568,6 +568,16 @@ xfs_vm_writepage( { struct xfs_writepage_ctx wpc = { }; + /* + * Given that we do not allow direct reclaim to call us, we should + * never be called while in a filesystem transaction. + */ + if (WARN_ON_ONCE(xfs_trans_context_active())) { + redirty_page_for_writepage(wbc, page); + unlock_page(page); + return 0; + } + return iomap_writepage(page, wbc, &wpc.ctx, &xfs_writeback_ops); } @@ -579,6 +589,13 @@ xfs_vm_writepages( struct xfs_writepage_ctx wpc = { }; xfs_iflags_clear(XFS_I(mapping->host), XFS_ITRUNCATED); + /* + * Given that we do not allow direct reclaim to call us, we should + * never be called while in a filesystem transaction. + */ + if (WARN_ON_ONCE(xfs_trans_context_active())) + return 0; + return iomap_writepages(mapping, wbc, &wpc.ctx, &xfs_writeback_ops); } diff --git a/fs/xfs/xfs_trans.h b/fs/xfs/xfs_trans.h index 12380eaaf7ce..0c8140147b9b 100644 --- a/fs/xfs/xfs_trans.h +++ b/fs/xfs/xfs_trans.h @@ -268,29 +268,41 @@ xfs_trans_item_relog( return lip->li_ops->iop_relog(lip, tp); } +static inline bool +xfs_trans_context_active(void) +{ + /* Use journal_info to indicate current is in a transaction */ + return current->journal_info != NULL; +} + static inline void xfs_trans_context_set(struct xfs_trans *tp) { + ASSERT(!current->journal_info); + current->journal_info = tp; tp->t_pflags = memalloc_nofs_save(); } static inline void xfs_trans_context_clear(struct xfs_trans *tp) { + /* + * If xfs_trans_context_swap() handed the NOFS context to a + * new transaction we do not clear the context here. + */ + if (current->journal_info != tp) + return; + + current->journal_info = NULL; memalloc_nofs_restore(tp->t_pflags); } static inline void xfs_trans_context_swap(struct xfs_trans *tp, struct xfs_trans *ntp) { + ASSERT(current->journal_info == tp); + current->journal_info = ntp; ntp->t_pflags = tp->t_pflags; - /* - * For the rolling transaction, we have to set NOFS in the old - * transaction's t_pflags so that when we clear the context on - * the old transaction we don't actually change the thread's NOFS - * state. - */ - tp->t_pflags = current->flags | PF_MEMALLOC_NOFS; } #endif /* __XFS_TRANS_H__ */