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=-9.0 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 3516DC04EB8 for ; Tue, 4 Dec 2018 15:12:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 01F69206B7 for ; Tue, 4 Dec 2018 15:12:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 01F69206B7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-btrfs-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726629AbeLDPM0 (ORCPT ); Tue, 4 Dec 2018 10:12:26 -0500 Received: from mx2.suse.de ([195.135.220.15]:59520 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726042AbeLDPMZ (ORCPT ); Tue, 4 Dec 2018 10:12:25 -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 4B2DCAF4A for ; Tue, 4 Dec 2018 15:12:21 +0000 (UTC) Received: by ds.suse.cz (Postfix, from userid 10065) id DC324DAC39; Tue, 4 Dec 2018 16:12:02 +0100 (CET) From: David Sterba To: linux-btrfs@vger.kernel.org Cc: fdmanana@suse.com, David Sterba Subject: [PATCH 2/2] btrfs: scrub: move scrub_setup_ctx allocation out of device_list_mutex Date: Tue, 4 Dec 2018 16:11:56 +0100 Message-Id: X-Mailer: git-send-email 2.19.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org The scrub context is allocated with GFP_KERNEL and called from btrfs_scrub_dev under the fs_info::device_list_mutex. This is not safe regarding reclaim that could try to flush filesystem data in order to get the memory. And the device_list_mutex is held during superblock commit, so this would cause a lockup. Move the alocation and initialization before any changes that require the mutex. Signed-off-by: David Sterba --- fs/btrfs/scrub.c | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-) diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index ffcab263e057..051d14c9f013 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -3834,13 +3834,18 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, return -EINVAL; } + /* Allocate outside of device_list_mutex */ + sctx = scrub_setup_ctx(fs_info, is_dev_replace); + if (IS_ERR(sctx)) + return PTR_ERR(sctx); mutex_lock(&fs_info->fs_devices->device_list_mutex); dev = btrfs_find_device(fs_info, devid, NULL, NULL); if (!dev || (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state) && !is_dev_replace)) { mutex_unlock(&fs_info->fs_devices->device_list_mutex); - return -ENODEV; + ret = -ENODEV; + goto out_free_ctx; } if (!is_dev_replace && !readonly && @@ -3848,7 +3853,8 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, mutex_unlock(&fs_info->fs_devices->device_list_mutex); btrfs_err_in_rcu(fs_info, "scrub: device %s is not writable", rcu_str_deref(dev->name)); - return -EROFS; + ret = -EROFS; + goto out_free_ctx; } mutex_lock(&fs_info->scrub_lock); @@ -3856,7 +3862,8 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &dev->dev_state)) { mutex_unlock(&fs_info->scrub_lock); mutex_unlock(&fs_info->fs_devices->device_list_mutex); - return -EIO; + ret = -EIO; + goto out_free_ctx; } btrfs_dev_replace_read_lock(&fs_info->dev_replace); @@ -3866,7 +3873,8 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, btrfs_dev_replace_read_unlock(&fs_info->dev_replace); mutex_unlock(&fs_info->scrub_lock); mutex_unlock(&fs_info->fs_devices->device_list_mutex); - return -EINPROGRESS; + ret = -EINPROGRESS; + goto out_free_ctx; } btrfs_dev_replace_read_unlock(&fs_info->dev_replace); @@ -3874,16 +3882,9 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, if (ret) { mutex_unlock(&fs_info->scrub_lock); mutex_unlock(&fs_info->fs_devices->device_list_mutex); - return ret; + goto out_free_ctx; } - sctx = scrub_setup_ctx(fs_info, is_dev_replace); - if (IS_ERR(sctx)) { - mutex_unlock(&fs_info->scrub_lock); - mutex_unlock(&fs_info->fs_devices->device_list_mutex); - scrub_workers_put(fs_info); - return PTR_ERR(sctx); - } sctx->readonly = readonly; dev->scrub_ctx = sctx; mutex_unlock(&fs_info->fs_devices->device_list_mutex); @@ -3936,6 +3937,11 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, scrub_put_ctx(sctx); + return ret; + +out_free_ctx: + scrub_free_ctx(sctx); + return ret; } -- 2.19.1