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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 77DC9C468C1 for ; Mon, 10 Jun 2019 09:37:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 598682082E for ; Mon, 10 Jun 2019 09:37:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389070AbfFJJha (ORCPT ); Mon, 10 Jun 2019 05:37:30 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:18540 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2389056AbfFJJha (ORCPT ); Mon, 10 Jun 2019 05:37:30 -0400 Received: from DGGEMS402-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id C663E4202C791DA4E475; Mon, 10 Jun 2019 17:37:27 +0800 (CST) Received: from architecture4.huawei.com (10.140.130.215) by smtp.huawei.com (10.3.19.202) with Microsoft SMTP Server (TLS) id 14.3.439.0; Mon, 10 Jun 2019 17:37:21 +0800 From: Gao Xiang To: Chao Yu , Greg Kroah-Hartman , CC: LKML , , "Chao Yu" , Miao Xie , , Fang Wei , Gao Xiang , Subject: [PATCH 1/2] staging: erofs: add requirements field in superblock Date: Mon, 10 Jun 2019 17:36:39 +0800 Message-ID: <20190610093640.96705-1-gaoxiang25@huawei.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.140.130.215] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There are some backward incompatible optimizations pending for months, mainly due to on-disk format expensions. However, we should ensure that it cannot be mounted with old kernels. Otherwise, it will causes unexpected behaviors. Fixes: ba2b77a82022 ("staging: erofs: add super block operations") Cc: # 4.19+ Signed-off-by: Gao Xiang --- drivers/staging/erofs/erofs_fs.h | 11 +++++++++-- drivers/staging/erofs/super.c | 8 ++++++++ 2 files changed, 17 insertions(+), 2 deletions(-) diff --git a/drivers/staging/erofs/erofs_fs.h b/drivers/staging/erofs/erofs_fs.h index fa52898df006..531821757845 100644 --- a/drivers/staging/erofs/erofs_fs.h +++ b/drivers/staging/erofs/erofs_fs.h @@ -17,10 +17,16 @@ #define EROFS_SUPER_MAGIC_V1 0xE0F5E1E2 #define EROFS_SUPER_OFFSET 1024 +/* + * Any bits that aren't in EROFS_ALL_REQUIREMENTS should be + * incompatible with this kernel version. + */ +#define EROFS_ALL_REQUIREMENTS 0 + struct erofs_super_block { /* 0 */__le32 magic; /* in the little endian */ /* 4 */__le32 checksum; /* crc32c(super_block) */ -/* 8 */__le32 features; +/* 8 */__le32 features; /* extra features for the image */ /* 12 */__u8 blkszbits; /* support block_size == PAGE_SIZE only */ /* 13 */__u8 reserved; @@ -34,8 +40,9 @@ struct erofs_super_block { /* 44 */__le32 xattr_blkaddr; /* 48 */__u8 uuid[16]; /* 128-bit uuid for volume */ /* 64 */__u8 volume_name[16]; /* volume name */ +/* 80 */__le32 requirements; /* all mandatory minimum requirements */ -/* 80 */__u8 reserved2[48]; /* 128 bytes */ +/* 84 */__u8 reserved2[44]; /* 128 bytes */ } __packed; /* diff --git a/drivers/staging/erofs/super.c b/drivers/staging/erofs/super.c index f580d4ef77a1..815e5825db59 100644 --- a/drivers/staging/erofs/super.c +++ b/drivers/staging/erofs/super.c @@ -104,6 +104,14 @@ static int superblock_read(struct super_block *sb) goto out; } + /* check if the kernel meets all mandatory requirements */ + if (le32_to_cpu(layout->requirements) & (~EROFS_ALL_REQUIREMENTS)) { + errln("too old to meet minimum requirements: %x supported: %x", + le32_to_cpu(layout->requirements), + EROFS_ALL_REQUIREMENTS); + goto out; + } + sbi->blocks = le32_to_cpu(layout->blocks); sbi->meta_blkaddr = le32_to_cpu(layout->meta_blkaddr); #ifdef CONFIG_EROFS_FS_XATTR -- 2.17.1