From patchwork Mon Sep 18 09:11:54 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 9956011 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id BE963601E9 for ; Mon, 18 Sep 2017 09:23:56 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AF55528930 for ; Mon, 18 Sep 2017 09:23:56 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A43D928C0A; Mon, 18 Sep 2017 09:23:56 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2D94928930 for ; Mon, 18 Sep 2017 09:23:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753196AbdIRJXJ (ORCPT ); Mon, 18 Sep 2017 05:23:09 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:56658 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932463AbdIRJRA (ORCPT ); Mon, 18 Sep 2017 05:17:00 -0400 Received: from localhost (LFbn-1-12253-150.w90-92.abo.wanadoo.fr [90.92.67.150]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 6B5187AA; Mon, 18 Sep 2017 09:16:59 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , linux-xfs@vger.kernel.org, "Darrick J . Wong" , Christoph Hellwig , Nikolay Borisov Subject: [PATCH 4.9 45/78] xfs: fix multi-AG deadlock in xfs_bunmapi Date: Mon, 18 Sep 2017 11:11:54 +0200 Message-Id: <20170918091133.088816511@linuxfoundation.org> X-Mailer: git-send-email 2.14.1 In-Reply-To: <20170918091126.077483037@linuxfoundation.org> References: <20170918091126.077483037@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ commit 5b094d6dac0451ad89b1dc088395c7b399b7e9e8 upstream. Just like in the allocator we must avoid touching multiple AGs out of order when freeing blocks, as freeing still locks the AGF and can cause the same AB-BA deadlocks as in the allocation path. Signed-off-by: Christoph Hellwig Reported-by: Nikolay Borisov Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong Signed-off-by: Greg Kroah-Hartman --- fs/xfs/libxfs/xfs_bmap.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html --- a/fs/xfs/libxfs/xfs_bmap.c +++ b/fs/xfs/libxfs/xfs_bmap.c @@ -5556,6 +5556,7 @@ __xfs_bunmapi( xfs_fsblock_t sum; xfs_filblks_t len = *rlen; /* length to unmap in file */ xfs_fileoff_t max_len; + xfs_agnumber_t prev_agno = NULLAGNUMBER, agno; trace_xfs_bunmap(ip, bno, len, flags, _RET_IP_); @@ -5658,6 +5659,17 @@ __xfs_bunmapi( ASSERT(ep != NULL); del = got; wasdel = isnullstartblock(del.br_startblock); + + /* + * Make sure we don't touch multiple AGF headers out of order + * in a single transaction, as that could cause AB-BA deadlocks. + */ + if (!wasdel) { + agno = XFS_FSB_TO_AGNO(mp, del.br_startblock); + if (prev_agno != NULLAGNUMBER && prev_agno > agno) + break; + prev_agno = agno; + } if (got.br_startoff < start) { del.br_startoff = start; del.br_blockcount -= start - got.br_startoff;