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=-10.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,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 5DDF5C49ED7 for ; Fri, 13 Sep 2019 13:30:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 37CAC206A5 for ; Fri, 13 Sep 2019 13:30:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568381457; bh=KPBt0vTCOmRrJNhkIgQw67qoTqslgfitXdMMk7LF4lc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=aQ+WxlUXJSvd+EYlq9zmO/z5meyY4t+ncl/47W5bSa/218x3DDTEWmMlW0b+/RFCz mNISDIsz+euDnpb2ElPTU8nloO+m6Hz91rqLrHEac8VDKRjjtVQwI7kikkk//J7Z19 zBqhjwgY60RK801LpsAHOBv/7f236pVzaCHFkUOA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389746AbfIMNPu (ORCPT ); Fri, 13 Sep 2019 09:15:50 -0400 Received: from mail.kernel.org ([198.145.29.99]:42186 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389740AbfIMNPt (ORCPT ); Fri, 13 Sep 2019 09:15:49 -0400 Received: from localhost (unknown [104.132.45.99]) (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 D7448214AE; Fri, 13 Sep 2019 13:15:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568380548; bh=KPBt0vTCOmRrJNhkIgQw67qoTqslgfitXdMMk7LF4lc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=x1JeNS9C26JB4u9AfwBe4dOq4mMLsnt3v8y+po9qcRwFnbVsx3MIMg+uP12V1P1Fu 1oEi+SmfAOaFEs+806S3zGwU+o1GLmo3jn+ALFcvJl+ppv/zq44/O4458NS8HWHrdd b9CxfAp8vEaE4u7TDQEt4oh7LIXyj3VhuL9xONmM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, David Sterba , Sasha Levin Subject: [PATCH 4.19 100/190] btrfs: scrub: move scrub_setup_ctx allocation out of device_list_mutex Date: Fri, 13 Sep 2019 14:05:55 +0100 Message-Id: <20190913130607.587164373@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190913130559.669563815@linuxfoundation.org> References: <20190913130559.669563815@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org [ Upstream commit 0e94c4f45d14cf89d1f40c91b0a8517e791672a7 ] 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 Signed-off-by: Sasha Levin --- 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 efaad3e1b295a..56c4d2236484f 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -3837,13 +3837,18 @@ 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 && @@ -3851,7 +3856,8 @@ 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); @@ -3859,7 +3865,8 @@ 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); @@ -3869,7 +3876,8 @@ 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); @@ -3877,16 +3885,9 @@ 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); @@ -3939,6 +3940,11 @@ 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; } -- 2.20.1