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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1E8B7C54EBD for ; Sat, 7 Jan 2023 01:38:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235970AbjAGBh7 (ORCPT ); Fri, 6 Jan 2023 20:37:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43424 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229751AbjAGBh6 (ORCPT ); Fri, 6 Jan 2023 20:37:58 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8FE927D9FD; Fri, 6 Jan 2023 17:37:56 -0800 (PST) Received: from dggpeml500021.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4NpjQJ3kRbzqTtp; Sat, 7 Jan 2023 09:33:12 +0800 (CST) Received: from [10.174.177.174] (10.174.177.174) by dggpeml500021.china.huawei.com (7.185.36.21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.34; Sat, 7 Jan 2023 09:37:54 +0800 Message-ID: Date: Sat, 7 Jan 2023 09:37:53 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.1.2 Subject: Re: [PATCH 1/2] ext4: fail ext4_iget if special inode unallocated To: Jan Kara CC: , , , , , , , =?UTF-8?Q?Lu=c3=ads_Henriques?= References: <20230106104706.2410740-1-libaokun1@huawei.com> <20230106104706.2410740-2-libaokun1@huawei.com> <20230106142846.rzkflbdedv2oyrro@quack3> Content-Language: en-US From: Baokun Li In-Reply-To: <20230106142846.rzkflbdedv2oyrro@quack3> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.177.174] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpeml500021.china.huawei.com (7.185.36.21) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On 2023/1/6 22:28, Jan Kara wrote: > On Fri 06-01-23 18:47:05, Baokun Li wrote: >> In ext4_fill_super(), EXT4_ORPHAN_FS flag is cleared after >> ext4_orphan_cleanup() is executed. Therefore, when __ext4_iget() is >> called to get an inode whose i_nlink is 0 when the flag exists, no error >> is returned. If the inode is a special inode, a null pointer dereference >> may occur. If the value of i_nlink is 0 for any inodes (except boot loader >> inodes) got by using the EXT4_IGET_SPECIAL flag, the current file system >> is corrupted. Therefore, make the ext4_iget() function return an error if >> it gets such an abnormal special inode. >> >> Link: https://bugzilla.kernel.org/show_bug.cgi?id=199179 >> Link: https://bugzilla.kernel.org/show_bug.cgi?id=216541 >> Link: https://bugzilla.kernel.org/show_bug.cgi?id=216539 >> Reported-by: Luís Henriques >> Suggested-by: Theodore Ts'o >> Signed-off-by: Baokun Li > Thanks for the patch! A few comments below. > >> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c >> index 9d9f414f99fe..3f7cfa91ba89 100644 >> --- a/fs/ext4/inode.c >> +++ b/fs/ext4/inode.c >> @@ -4872,13 +4872,6 @@ struct inode *__ext4_iget(struct super_block *sb, unsigned long ino, >> goto bad_inode; >> raw_inode = ext4_raw_inode(&iloc); >> >> - if ((ino == EXT4_ROOT_INO) && (raw_inode->i_links_count == 0)) { >> - ext4_error_inode(inode, function, line, 0, >> - "iget: root inode unallocated"); >> - ret = -EFSCORRUPTED; >> - goto bad_inode; >> - } >> - >> if ((flags & EXT4_IGET_HANDLE) && >> (raw_inode->i_links_count == 0) && (raw_inode->i_mode == 0)) { >> ret = -ESTALE; >> @@ -4951,10 +4944,13 @@ struct inode *__ext4_iget(struct super_block *sb, unsigned long ino, >> * NeilBrown 1999oct15 >> */ >> if (inode->i_nlink == 0) { >> - if ((inode->i_mode == 0 || >> + if ((inode->i_mode == 0 || (flags & EXT4_IGET_SPECIAL) || > ^ extra parenthesis here ^ Indeed, I'll remove the extra parenthesis. >> !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) && >> ino != EXT4_BOOT_LOADER_INO) { >> /* this inode is deleted */ >> + if (flags & EXT4_IGET_SPECIAL) >> + ext4_error_inode(inode, function, line, 0, >> + "iget: special inode unallocated"); > I think it would be better to return -EFSCORRUPTED and not -ESTALE in this > case. Totally agree! For special inode, -EFSCORRUPTED is more reasonable. >> ret = -ESTALE; >> goto bad_inode; >> } > Otherwise the patch looks good to me. > > Honza > Thank you very much for your review！ I will send a patch V2 with the changes suggested by you. -- With Best Regards, Baokun Li .