From nobody Mon Apr 13 20:05:37 2026 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 610ECC4332F for ; Thu, 17 Nov 2022 03:42:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238928AbiKQDma (ORCPT ); Wed, 16 Nov 2022 22:42:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55490 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234067AbiKQDmX (ORCPT ); Wed, 16 Nov 2022 22:42:23 -0500 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6B3A4275E2; Wed, 16 Nov 2022 19:42:22 -0800 (PST) Received: from dggpeml500021.china.huawei.com (unknown [172.30.72.57]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4NCQcS1bgYzqSWR; Thu, 17 Nov 2022 11:38:32 +0800 (CST) Received: from huawei.com (10.175.127.227) 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 15.1.2375.31; Thu, 17 Nov 2022 11:42:20 +0800 From: Baokun Li To: CC: , , , , , , , Subject: [PATCH v3 2/3] ext4: fix corrupt backup group descriptors after online resize Date: Thu, 17 Nov 2022 12:03:40 +0800 Message-ID: <20221117040341.1380702-3-libaokun1@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20221117040341.1380702-1-libaokun1@huawei.com> References: <20221117040341.1380702-1-libaokun1@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.175.127.227] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpeml500021.china.huawei.com (7.185.36.21) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" In commit 9a8c5b0d0615 ("ext4: update the backup superblock's at the end of the online resize"), it is assumed that update_backups() only updates backup superblocks, so each b_data is treated as a backupsuper block to update its s_block_group_nr and s_checksum. However, update_backups() also updates the backup group descriptors, which causes the backup group descriptors to be corrupted. The above commit fixes the problem of invalid checksum of the backup superblock. The root cause of this problem is that the checksum of ext4_update_super() is not set correctly. This problem has been fixed in the previous patch ("ext4: fix bad checksum after online resize"). However, we do need to set block_group_nr for the backup superblock in update_backups(). When a block is in a group that contains a backup superblock, and the block is the first block in the group, the block is definitely a superblock. We add a helper function that includes setting s_block_group_nr and updating checksum, and then call it only when the above conditions are met to prevent the backup group descriptors from being incorrectly modified. Fixes: 9a8c5b0d0615 ("ext4: update the backup superblock's at the end of th= e online resize") Signed-off-by: Baokun Li Reviewed-by: Jan Kara --- V2->V3: Modify the scheme and retain s_block_group_nr. fs/ext4/resize.c | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-) diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c index cb99b410c9fa..66ceabbd83ad 100644 --- a/fs/ext4/resize.c +++ b/fs/ext4/resize.c @@ -1110,6 +1110,16 @@ static int reserve_backup_gdb(handle_t *handle, stru= ct inode *inode, return err; } =20 +static inline void ext4_set_block_group_nr(struct super_block *sb, char *d= ata, + ext4_group_t group) +{ + struct ext4_super_block *es =3D (struct ext4_super_block *) data; + + es->s_block_group_nr =3D cpu_to_le16(group); + if (ext4_has_metadata_csum(sb)) + es->s_checksum =3D ext4_superblock_csum(sb, es); +} + /* * Update the backup copies of the ext4 metadata. These don't need to be = part * of the main resize transaction, because e2fsck will re-write them if th= ere @@ -1158,7 +1168,8 @@ static void update_backups(struct super_block *sb, se= ctor_t blk_off, char *data, while (group < sbi->s_groups_count) { struct buffer_head *bh; ext4_fsblk_t backup_block; - struct ext4_super_block *es; + int has_super =3D ext4_bg_has_super(sb, group); + ext4_fsblk_t first_block =3D ext4_group_first_block_no(sb, group); =20 /* Out of journal space, and can't get more - abort - so sad */ err =3D ext4_resize_ensure_credits_batch(handle, 1); @@ -1168,8 +1179,7 @@ static void update_backups(struct super_block *sb, se= ctor_t blk_off, char *data, if (meta_bg =3D=3D 0) backup_block =3D ((ext4_fsblk_t)group) * bpg + blk_off; else - backup_block =3D (ext4_group_first_block_no(sb, group) + - ext4_bg_has_super(sb, group)); + backup_block =3D first_block + has_super; =20 bh =3D sb_getblk(sb, backup_block); if (unlikely(!bh)) { @@ -1187,10 +1197,8 @@ static void update_backups(struct super_block *sb, s= ector_t blk_off, char *data, memcpy(bh->b_data, data, size); if (rest) memset(bh->b_data + size, 0, rest); - es =3D (struct ext4_super_block *) bh->b_data; - es->s_block_group_nr =3D cpu_to_le16(group); - if (ext4_has_metadata_csum(sb)) - es->s_checksum =3D ext4_superblock_csum(sb, es); + if (has_super && (backup_block =3D=3D first_block)) + ext4_set_block_group_nr(sb, bh->b_data, group); set_buffer_uptodate(bh); unlock_buffer(bh); err =3D ext4_handle_dirty_metadata(handle, NULL, bh); --=20 2.31.1