From mboxrd@z Thu Jan 1 00:00:00 1970 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 F39B1C4724C for ; Fri, 1 May 2020 13:42:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CED20208DB for ; Fri, 1 May 2020 13:42:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588340553; bh=FR43RgaZaK0hs2+jq2BnsmLQUirWJ4wclBUZsQbFpLI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=NEC+U833TaE2UsobYxaFQLVys5q3Kpud/bbSt0zqkLzSfALni+b6hqAr2mmIGrFfE C2zJIHsbdCF5L/0jsUsDQdqL0Hn0EsbV3vWgxm/Z1LSB0u4w5BceZRfIG8EntekmU+ 5Oi8dpJnDIQ5gXlLQorUNECc/dygn1+tKR1yhzF0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731026AbgEANmd (ORCPT ); Fri, 1 May 2020 09:42:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:43070 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731510AbgEANm1 (ORCPT ); Fri, 1 May 2020 09:42:27 -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 F0E42216FD; Fri, 1 May 2020 13:42:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588340546; bh=FR43RgaZaK0hs2+jq2BnsmLQUirWJ4wclBUZsQbFpLI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rZTweV8EKLhXA3UL97rXXaLl9PUjYpWRrXpayek4jwNp4QeA45DBDBgDuq/3rKhqo ia+kgiU1Bnom6mbt0fUJVix/c+ikLgdVQPhm3K7hJJgQPUm8Hz1LXPMiDh+D7bQipu cqpOMjGo/I+8TLxGaTS/uTtQ+AYPwLMcu7zMEjYQ= 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 5.6 038/106] xfs: acquire superblock freeze protection on eofblocks scans Date: Fri, 1 May 2020 15:23:11 +0200 Message-Id: <20200501131548.426288076@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200501131543.421333643@linuxfoundation.org> References: <20200501131543.421333643@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 @@ -907,7 +907,12 @@ 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); } @@ -934,7 +939,12 @@ 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 @@ -2264,7 +2264,10 @@ 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: