From patchwork Tue Mar 10 12:39:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 229506 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 706B5C10F27 for ; Tue, 10 Mar 2020 13:28:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4243A24649 for ; Tue, 10 Mar 2020 13:28:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583846928; bh=zIkW5w5iHGe1BG22rwFNnqCuldDOaOwm7rAIwYEbfRo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=dpwX83Ffa/RERbpstrbB8j8AAi1BcfxV7BCS4XSI7T8yL761aA4Zy7VZHe4+0GENf nljlaFWhmRW0szkF4H9HmXqjzp28LHk31/WXnW/8JP5HHe9UfJrtQ7hEQaL0HKnk4a x1F5vSJY61H/zDyvKoWgWxosfge3QWdbPolArpTY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728593AbgCJMxE (ORCPT ); Tue, 10 Mar 2020 08:53:04 -0400 Received: from mail.kernel.org ([198.145.29.99]:58808 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729094AbgCJMxA (ORCPT ); Tue, 10 Mar 2020 08:53:00 -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 39C3E24692; Tue, 10 Mar 2020 12:52:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1583844778; bh=zIkW5w5iHGe1BG22rwFNnqCuldDOaOwm7rAIwYEbfRo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0bgMR968t8JMrt0v/w2bS5Os0zfA40AakKCggt4Te5UKbaxqknrJqZBcXmCuNnT5o L0GuzM7uc59LNt+RK6u75mVT4TA2MrUXcUC6euuqIFLpG4f48DBCWyD1uokPrzcry8 OtITkouUHaUboNQERnrrlzFBkqQEuN3kXSjtrM0M= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Corey Marthaler , Mikulas Patocka , Mike Snitzer Subject: [PATCH 5.4 108/168] dm: report suspended device during destroy Date: Tue, 10 Mar 2020 13:39:14 +0100 Message-Id: <20200310123646.318562515@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200310123635.322799692@linuxfoundation.org> References: <20200310123635.322799692@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: Mikulas Patocka commit adc0daad366b62ca1bce3e2958a40b0b71a8b8b3 upstream. The function dm_suspended returns true if the target is suspended. However, when the target is being suspended during unload, it returns false. An example where this is a problem: the test "!dm_suspended(wc->ti)" in writecache_writeback is not sufficient, because dm_suspended returns zero while writecache_suspend is in progress. As is, without an enhanced dm_suspended, simply switching from flush_workqueue to drain_workqueue still emits warnings: workqueue writecache-writeback: drain_workqueue() isn't complete after 10 tries workqueue writecache-writeback: drain_workqueue() isn't complete after 100 tries workqueue writecache-writeback: drain_workqueue() isn't complete after 200 tries workqueue writecache-writeback: drain_workqueue() isn't complete after 300 tries workqueue writecache-writeback: drain_workqueue() isn't complete after 400 tries writecache_suspend calls flush_workqueue(wc->writeback_wq) - this function flushes the current work. However, the workqueue may re-queue itself and flush_workqueue doesn't wait for re-queued works to finish. Because of this - the function writecache_writeback continues execution after the device was suspended and then concurrently with writecache_dtr, causing a crash in writecache_writeback. We must use drain_workqueue - that waits until the work and all re-queued works finish. As a prereq for switching to drain_workqueue, this commit fixes dm_suspended to return true after the presuspend hook and before the postsuspend hook - just like during a normal suspend. It allows simplifying the dm-integrity and dm-writecache targets so that they don't have to maintain suspended flags on their own. With this change use of drain_workqueue() can be used effectively. This change was tested with the lvm2 testsuite and cryptsetup testsuite and the are no regressions. Fixes: 48debafe4f2f ("dm: add writecache target") Cc: stable@vger.kernel.org # 4.18+ Reported-by: Corey Marthaler Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-integrity.c | 12 +++++------- drivers/md/dm-writecache.c | 2 +- drivers/md/dm.c | 1 + 3 files changed, 7 insertions(+), 8 deletions(-) --- a/drivers/md/dm-integrity.c +++ b/drivers/md/dm-integrity.c @@ -199,12 +199,13 @@ struct dm_integrity_c { __u8 log2_blocks_per_bitmap_bit; unsigned char mode; - int suspending; int failed; struct crypto_shash *internal_hash; + struct dm_target *ti; + /* these variables are locked with endio_wait.lock */ struct rb_root in_progress; struct list_head wait_list; @@ -2311,7 +2312,7 @@ static void integrity_writer(struct work unsigned prev_free_sectors; /* the following test is not needed, but it tests the replay code */ - if (READ_ONCE(ic->suspending) && !ic->meta_dev) + if (unlikely(dm_suspended(ic->ti)) && !ic->meta_dev) return; spin_lock_irq(&ic->endio_wait.lock); @@ -2372,7 +2373,7 @@ static void integrity_recalc(struct work next_chunk: - if (unlikely(READ_ONCE(ic->suspending))) + if (unlikely(dm_suspended(ic->ti))) goto unlock_ret; range.logical_sector = le64_to_cpu(ic->sb->recalc_sector); @@ -2800,8 +2801,6 @@ static void dm_integrity_postsuspend(str del_timer_sync(&ic->autocommit_timer); - WRITE_ONCE(ic->suspending, 1); - if (ic->recalc_wq) drain_workqueue(ic->recalc_wq); @@ -2830,8 +2829,6 @@ static void dm_integrity_postsuspend(str #endif } - WRITE_ONCE(ic->suspending, 0); - BUG_ON(!RB_EMPTY_ROOT(&ic->in_progress)); ic->journal_uptodate = true; @@ -3615,6 +3612,7 @@ static int dm_integrity_ctr(struct dm_ta } ti->private = ic; ti->per_io_data_size = sizeof(struct dm_integrity_io); + ic->ti = ti; ic->in_progress = RB_ROOT; INIT_LIST_HEAD(&ic->wait_list); --- a/drivers/md/dm-writecache.c +++ b/drivers/md/dm-writecache.c @@ -838,7 +838,7 @@ static void writecache_suspend(struct dm } wc_unlock(wc); - flush_workqueue(wc->writeback_wq); + drain_workqueue(wc->writeback_wq); wc_lock(wc); if (flush_on_suspend) --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -2389,6 +2389,7 @@ static void __dm_destroy(struct mapped_d map = dm_get_live_table(md, &srcu_idx); if (!dm_suspended_md(md)) { dm_table_presuspend_targets(map); + set_bit(DMF_SUSPENDED, &md->flags); dm_table_postsuspend_targets(map); } /* dm_put_live_table must be before msleep, otherwise deadlock is possible */