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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 5BE4AC04AB5 for ; Mon, 3 Jun 2019 10:34:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3C0C4280A3 for ; Mon, 3 Jun 2019 10:34:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727122AbfFCKef (ORCPT ); Mon, 3 Jun 2019 06:34:35 -0400 Received: from szxga07-in.huawei.com ([45.249.212.35]:49380 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726791AbfFCKef (ORCPT ); Mon, 3 Jun 2019 06:34:35 -0400 Received: from DGGEMS408-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id B8A478589F240428C33B; Mon, 3 Jun 2019 18:34:32 +0800 (CST) Received: from [10.134.22.195] (10.134.22.195) by smtp.huawei.com (10.3.19.208) with Microsoft SMTP Server (TLS) id 14.3.439.0; Mon, 3 Jun 2019 18:34:29 +0800 Subject: Re: [PATCH v3 2/4] f2fs: Fix root reserved on remount To: Daniel Rosenberg , Jaegeuk Kim , Jonathan Corbet , CC: , , , References: <20190530004906.261170-1-drosen@google.com> <20190530004906.261170-3-drosen@google.com> From: Chao Yu Message-ID: Date: Mon, 3 Jun 2019 18:34:28 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20190530004906.261170-3-drosen@google.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.134.22.195] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/5/30 8:49, Daniel Rosenberg wrote: > On a remount, you can currently set root reserved if it was not > previously set. This can cause an underflow if reserved has been set to > a very high value, since then root reserved + current reserved could be > greater than user_block_count. inc_valid_block_count later subtracts out > these values from user_block_count, causing an underflow. > > Signed-off-by: Daniel Rosenberg Reviewed-by: Chao Yu Thanks,