From patchwork Fri May 1 13:22:40 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 226542 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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY, 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 25740C47254 for ; Fri, 1 May 2020 13:53:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0607D216FD for ; Fri, 1 May 2020 13:53:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588341193; bh=DEKOV80S+EgZGm5x0oH/1MuU21eybiRSXazP2DjWCGA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ffFfOQ/zIFWvdyfGUKLaOjExmWC/xFSOLMvOk9U0bKIf+hSjPMCKmHNby+h9RKkMp br73DD2iKUl4rUfGVxsjv4jq6enAkLOQv5/+0HpamqlKAlsGs/jv5NDH6YpxqQP0kf bKb+1S08hmtRM4Y5/wBGLiTeq8947OomrNbH142k= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730880AbgEANgk (ORCPT ); Fri, 1 May 2020 09:36:40 -0400 Received: from mail.kernel.org ([198.145.29.99]:35206 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730877AbgEANgi (ORCPT ); Fri, 1 May 2020 09:36:38 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7734E208DB; Fri, 1 May 2020 13:36:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588340197; bh=DEKOV80S+EgZGm5x0oH/1MuU21eybiRSXazP2DjWCGA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vw+kNrV62uLWJ/fZfXCe4CCxeqd6aAUxm0oRtIJCUupGyMlm7vbfA1XHXAI1N+X9S YcRm7XIHEEzE6sGY5Pqr2TwYweFpZYWypZ8TgeVSEzZrm8BI9gYV5AvBPkWriuCB1N b/NQcpqwlrUAsSzXyI7VsiiEGIuvekoUbXLfbaaU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Paul Furtado , Brian Foster , Chandan Rajendra , Christoph Hellwig , Allison Collins , "Darrick J. Wong" Subject: [PATCH 4.19 15/46] xfs: acquire superblock freeze protection on eofblocks scans Date: Fri, 1 May 2020 15:22:40 +0200 Message-Id: <20200501131503.899313616@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200501131457.023036302@linuxfoundation.org> References: <20200501131457.023036302@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Brian Foster commit 4b674b9ac852937af1f8c62f730c325fb6eadcdb upstream. The filesystem freeze sequence in XFS waits on any background eofblocks or cowblocks scans to complete before the filesystem is quiesced. At this point, the freezer has already stopped the transaction subsystem, however, which means a truncate or cowblock cancellation in progress is likely blocked in transaction allocation. This results in a deadlock between freeze and the associated scanner. Fix this problem by holding superblock write protection across calls into the block reapers. Since protection for background scans is acquired from the workqueue task context, trylock to avoid a similar deadlock between freeze and blocking on the write lock. Fixes: d6b636ebb1c9f ("xfs: halt auto-reclamation activities while rebuilding rmap") Reported-by: Paul Furtado Signed-off-by: Brian Foster Reviewed-by: Chandan Rajendra Reviewed-by: Christoph Hellwig Reviewed-by: Allison Collins Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong Signed-off-by: Greg Kroah-Hartman --- fs/xfs/xfs_icache.c | 10 ++++++++++ fs/xfs/xfs_ioctl.c | 5 ++++- 2 files changed, 14 insertions(+), 1 deletion(-) --- a/fs/xfs/xfs_icache.c +++ b/fs/xfs/xfs_icache.c @@ -902,7 +902,12 @@ xfs_eofblocks_worker( { struct xfs_mount *mp = container_of(to_delayed_work(work), struct xfs_mount, m_eofblocks_work); + + if (!sb_start_write_trylock(mp->m_super)) + return; xfs_icache_free_eofblocks(mp, NULL); + sb_end_write(mp->m_super); + xfs_queue_eofblocks(mp); } @@ -929,7 +934,12 @@ xfs_cowblocks_worker( { struct xfs_mount *mp = container_of(to_delayed_work(work), struct xfs_mount, m_cowblocks_work); + + if (!sb_start_write_trylock(mp->m_super)) + return; xfs_icache_free_cowblocks(mp, NULL); + sb_end_write(mp->m_super); + xfs_queue_cowblocks(mp); } --- a/fs/xfs/xfs_ioctl.c +++ b/fs/xfs/xfs_ioctl.c @@ -2182,7 +2182,10 @@ xfs_file_ioctl( if (error) return error; - return xfs_icache_free_eofblocks(mp, &keofb); + sb_start_write(mp->m_super); + error = xfs_icache_free_eofblocks(mp, &keofb); + sb_end_write(mp->m_super); + return error; } default: