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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 9212EC432C0 for ; Fri, 22 Nov 2019 06:24:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6347620637 for ; Fri, 22 Nov 2019 06:24:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574403842; bh=/lcAWHBkLChrSM0oXx4xjHts2xF9XpAEnOD+MzhiIF4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=yqLIS5q6//xwj59NZF/cS99V+6n7lXd2qRvt3eUtJ+nSpQN1emlb2bM2xxadTHkgw I9xbuptKxuO9nsGktK+qP66GU5b8x6PLrLtVS5I6Tn0Epp8nuVYCE4jt7cy1ys7DX2 6mScf1KGR8KQoXwC3aFUHiumoNqMo4AngfV3zQ4Y= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728783AbfKVGYB (ORCPT ); Fri, 22 Nov 2019 01:24:01 -0500 Received: from mail.kernel.org ([198.145.29.99]:56746 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728188AbfKVFvf (ORCPT ); Fri, 22 Nov 2019 00:51:35 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 098112071C; Fri, 22 Nov 2019 05:51:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1574401894; bh=/lcAWHBkLChrSM0oXx4xjHts2xF9XpAEnOD+MzhiIF4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VRJGC0KenVClaPwYJX6lxBwzkXYrlorIWGUeqTeI+wLJBqAeUBBYZdMz0nZtT1lA3 FeU/jXx+NlHs051SDJAOnZ4NpicQpGQg+n4cz0ypoI8dpph4HRU9Jgz+g7aiNejGDo akLr8kf0VV9Vjwuoc5DvTj+ekqOms1HjsAPCL7NU= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Lars Ellenberg , Jens Axboe , Sasha Levin , drbd-dev@lists.linbit.com, linux-block@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 127/219] drbd: do not block when adjusting "disk-options" while IO is frozen Date: Fri, 22 Nov 2019 00:47:39 -0500 Message-Id: <20191122054911.1750-120-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191122054911.1750-1-sashal@kernel.org> References: <20191122054911.1750-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Lars Ellenberg [ Upstream commit f708bd08ecbdc23d03aaedf5b3311ebe44cfdb50 ] "suspending" IO is overloaded. It can mean "do not allow new requests" (obviously), but it also may mean "must not complete pending IO", for example while the fencing handlers do their arbitration. When adjusting disk options, we suspend io (disallow new requests), then wait for the activity-log to become unused (drain all IO completions), and possibly replace it with a new activity log of different size. If the other "suspend IO" aspect is active, pending IO completions won't happen, and we would block forever (unkillable drbdsetup process). Fix this by skipping the activity log adjustment if the "al-extents" setting did not change. Also, in case it did change, fail early without blocking if it looks like we would block forever. Signed-off-by: Lars Ellenberg Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- drivers/block/drbd/drbd_nl.c | 37 ++++++++++++++++++++++++++++-------- 1 file changed, 29 insertions(+), 8 deletions(-) diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c index 3366c1a91ee00..5b15ffd0c7f57 100644 --- a/drivers/block/drbd/drbd_nl.c +++ b/drivers/block/drbd/drbd_nl.c @@ -1515,6 +1515,30 @@ static void sanitize_disk_conf(struct drbd_device *device, struct disk_conf *dis } } +static int disk_opts_check_al_size(struct drbd_device *device, struct disk_conf *dc) +{ + int err = -EBUSY; + + if (device->act_log && + device->act_log->nr_elements == dc->al_extents) + return 0; + + drbd_suspend_io(device); + /* If IO completion is currently blocked, we would likely wait + * "forever" for the activity log to become unused. So we don't. */ + if (atomic_read(&device->ap_bio_cnt)) + goto out; + + wait_event(device->al_wait, lc_try_lock(device->act_log)); + drbd_al_shrink(device); + err = drbd_check_al_size(device, dc); + lc_unlock(device->act_log); + wake_up(&device->al_wait); +out: + drbd_resume_io(device); + return err; +} + int drbd_adm_disk_opts(struct sk_buff *skb, struct genl_info *info) { struct drbd_config_context adm_ctx; @@ -1577,15 +1601,12 @@ int drbd_adm_disk_opts(struct sk_buff *skb, struct genl_info *info) } } - drbd_suspend_io(device); - wait_event(device->al_wait, lc_try_lock(device->act_log)); - drbd_al_shrink(device); - err = drbd_check_al_size(device, new_disk_conf); - lc_unlock(device->act_log); - wake_up(&device->al_wait); - drbd_resume_io(device); - + err = disk_opts_check_al_size(device, new_disk_conf); if (err) { + /* Could be just "busy". Ignore? + * Introduce dedicated error code? */ + drbd_msg_put_info(adm_ctx.reply_skb, + "Try again without changing current al-extents setting"); retcode = ERR_NOMEM; goto fail_unlock; } -- 2.20.1