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=-18.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 D7C3AC49EA3 for ; Wed, 16 Jun 2021 15:36:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C40B7613CD for ; Wed, 16 Jun 2021 15:36:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235120AbhFPPiq (ORCPT ); Wed, 16 Jun 2021 11:38:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:51066 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234749AbhFPPhe (ORCPT ); Wed, 16 Jun 2021 11:37:34 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 07564613CB; Wed, 16 Jun 2021 15:35:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1623857728; bh=kvSrNLIh+uOkr9jxyOKYG8oS7k48Q+7gWUhGNQ4QAyk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=k0LfEa4eYvGJO1H3tEY/m1cKw5Ius2W4WHnxNin6h07xCYbl4uPZJGOWd0IvA+E3n nUlp+eQUG0Ve+VaxW2IA2c6zeXtL/w42Jk9UulWpgjztKdYU+xl7+iHzGgDYk58C8M 34Pcprl2mvJZ557lKHnAgJESMZeOriPzOgtN/tAM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Bob Peterson , Andreas Gruenbacher , Sasha Levin Subject: [PATCH 5.10 16/38] gfs2: fix a deadlock on withdraw-during-mount Date: Wed, 16 Jun 2021 17:33:25 +0200 Message-Id: <20210616152835.912416286@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210616152835.407925718@linuxfoundation.org> References: <20210616152835.407925718@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Bob Peterson [ Upstream commit 865cc3e9cc0b1d4b81c10d53174bced76decf888 ] Before this patch, gfs2 would deadlock because of the following sequence during mount: mount gfs2_fill_super gfs2_make_fs_rw <--- Detects IO error with glock kthread_stop(sdp->sd_quotad_process); <--- Blocked waiting for quotad to finish logd Detects IO error and the need to withdraw calls gfs2_withdraw gfs2_make_fs_ro kthread_stop(sdp->sd_quotad_process); <--- Blocked waiting for quotad to finish gfs2_quotad gfs2_statfs_sync gfs2_glock_wait <---- Blocked waiting for statfs glock to be granted glock_work_func do_xmote <---Detects IO error, can't release glock: blocked on withdraw glops->go_inval glock_blocked_by_withdraw requeue glock work & exit <--- work requeued, blocked by withdraw This patch makes a special exception for the statfs system inode glock, which allows the statfs glock UNLOCK to proceed normally. That allows the quotad daemon to exit during the withdraw, which allows the logd daemon to exit during the withdraw, which allows the mount to exit. Signed-off-by: Bob Peterson Signed-off-by: Andreas Gruenbacher Signed-off-by: Sasha Levin --- fs/gfs2/glock.c | 24 +++++++++++++++++++++--- 1 file changed, 21 insertions(+), 3 deletions(-) diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index ea2f2de44806..59130cbbd995 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -569,6 +569,16 @@ out_locked: spin_unlock(&gl->gl_lockref.lock); } +static bool is_system_glock(struct gfs2_glock *gl) +{ + struct gfs2_sbd *sdp = gl->gl_name.ln_sbd; + struct gfs2_inode *m_ip = GFS2_I(sdp->sd_statfs_inode); + + if (gl == m_ip->i_gl) + return true; + return false; +} + /** * do_xmote - Calls the DLM to change the state of a lock * @gl: The lock state @@ -658,17 +668,25 @@ skip_inval: * to see sd_log_error and withdraw, and in the meantime, requeue the * work for later. * + * We make a special exception for some system glocks, such as the + * system statfs inode glock, which needs to be granted before the + * gfs2_quotad daemon can exit, and that exit needs to finish before + * we can unmount the withdrawn file system. + * * However, if we're just unlocking the lock (say, for unmount, when * gfs2_gl_hash_clear calls clear_glock) and recovery is complete * then it's okay to tell dlm to unlock it. */ if (unlikely(sdp->sd_log_error && !gfs2_withdrawn(sdp))) gfs2_withdraw_delayed(sdp); - if (glock_blocked_by_withdraw(gl)) { - if (target != LM_ST_UNLOCKED || - test_bit(SDF_WITHDRAW_RECOVERY, &sdp->sd_flags)) { + if (glock_blocked_by_withdraw(gl) && + (target != LM_ST_UNLOCKED || + test_bit(SDF_WITHDRAW_RECOVERY, &sdp->sd_flags))) { + if (!is_system_glock(gl)) { gfs2_glock_queue_work(gl, GL_GLOCK_DFT_HOLD); goto out; + } else { + clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags); } } -- 2.30.2