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=-8.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,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 A89C8C65BAE for ; Thu, 13 Dec 2018 14:55:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6ACF52086D for ; Thu, 13 Dec 2018 14:55:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6ACF52086D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-block-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728709AbeLMOze (ORCPT ); Thu, 13 Dec 2018 09:55:34 -0500 Received: from mx2.suse.de ([195.135.220.15]:51510 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728612AbeLMOze (ORCPT ); Thu, 13 Dec 2018 09:55:34 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id ED825AD5C; Thu, 13 Dec 2018 14:55:32 +0000 (UTC) From: Coly Li To: linux-bcache@vger.kernel.org, axboe@kernel.dk Cc: linux-block@vger.kernel.org, Shenghui Wang , Coly Li Subject: [PATCH 06/12] bcache: cannot set writeback_running via sysfs if no writeback kthread created Date: Thu, 13 Dec 2018 22:53:51 +0800 Message-Id: <20181213145357.38528-7-colyli@suse.de> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20181213145357.38528-1-colyli@suse.de> References: <20181213145357.38528-1-colyli@suse.de> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org From: Shenghui Wang "echo 1 > writeback_running" marks writeback_running even if no writeback kthread created as "d_strtoul(writeback_running)" will simply set dc-> writeback_running without checking the existence of dc->writeback_thread. Add check for setting writeback_running via sysfs: if no writeback kthread available, reject setting to 1. v2 -> v3: * Make message on wrong assignment more clear. * Print name of bcache device instead of name of backing device. Signed-off-by: Shenghui Wang Signed-off-by: Coly Li --- drivers/md/bcache/sysfs.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c index d2e5c9892d4d..9d5fe12f0c9c 100644 --- a/drivers/md/bcache/sysfs.c +++ b/drivers/md/bcache/sysfs.c @@ -384,8 +384,25 @@ STORE(bch_cached_dev) mutex_lock(&bch_register_lock); size = __cached_dev_store(kobj, attr, buf, size); - if (attr == &sysfs_writeback_running) - bch_writeback_queue(dc); + if (attr == &sysfs_writeback_running) { + /* dc->writeback_running changed in __cached_dev_store() */ + if (IS_ERR_OR_NULL(dc->writeback_thread)) { + /* + * reject setting it to 1 via sysfs if writeback + * kthread is not created yet. + */ + if (dc->writeback_running) { + dc->writeback_running = false; + pr_err("%s: failed to run non-existent writeback thread", + dc->disk.disk->disk_name); + } + } else + /* + * writeback kthread will check if dc->writeback_running + * is true or false. + */ + bch_writeback_queue(dc); + } if (attr == &sysfs_writeback_percent) if (!test_and_set_bit(BCACHE_DEV_WB_RUNNING, &dc->disk.flags)) -- 2.16.4