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 1E4D4C6FA99 for ; Fri, 10 Mar 2023 12:53:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230124AbjCJMxG (ORCPT ); Fri, 10 Mar 2023 07:53:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41944 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230165AbjCJMwz (ORCPT ); Fri, 10 Mar 2023 07:52:55 -0500 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C3F8C10C721; Fri, 10 Mar 2023 04:52:52 -0800 (PST) Received: from kwepemm600013.china.huawei.com (unknown [172.30.72.57]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4PY5WR5MZhzHwTv; Fri, 10 Mar 2023 20:50:43 +0800 (CST) Received: from huawei.com (10.175.127.227) by kwepemm600013.china.huawei.com (7.193.23.68) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.21; Fri, 10 Mar 2023 20:52:50 +0800 From: Zhihao Cheng To: , , CC: , , , Subject: [PATCH 1/5] ext4: Fix reusing stale buffer heads from last failed mounting Date: Fri, 10 Mar 2023 20:52:02 +0800 Message-ID: <20230310125206.2867822-2-chengzhihao1@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20230310125206.2867822-1-chengzhihao1@huawei.com> References: <20230310125206.2867822-1-chengzhihao1@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.127.227] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To kwepemm600013.china.huawei.com (7.193.23.68) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Following process makes ext4 load stale buffer heads from last failed mounting in a new mounting operation: mount_bdev ext4_fill_super | ext4_load_and_init_journal | ext4_load_journal | jbd2_journal_load | load_superblock | journal_get_superblock | set_buffer_verified(bh) // buffer head is verified | jbd2_journal_recover // failed caused by EIO | goto failed_mount3a // skip 'sb->s_root' initialization deactivate_locked_super kill_block_super generic_shutdown_super if (sb->s_root) // false, skip ext4_put_super->invalidate_bdev-> // invalidate_mapping_pages->mapping_evict_folio-> // filemap_release_folio->try_to_free_buffers, which // cannot drop buffer head. blkdev_put blkdev_put_whole if (atomic_dec_and_test(&bdev->bd_openers)) // false, systemd-udev happens to open the device. Then // blkdev_flush_mapping->kill_bdev->truncate_inode_pages-> // truncate_inode_folio->truncate_cleanup_folio-> // folio_invalidate->block_invalidate_folio-> // filemap_release_folio->try_to_free_buffers will be skipped, // dropping buffer head is missed again. Second mount: ext4_fill_super ext4_load_and_init_journal ext4_load_journal ext4_get_journal jbd2_journal_init_inode journal_init_common bh = getblk_unmovable bh = __find_get_block // Found stale bh in last failed mounting journal->j_sb_buffer = bh jbd2_journal_load load_superblock journal_get_superblock if (buffer_verified(bh)) // true, skip journal->j_format_version = 2, value is 0 jbd2_journal_recover do_one_pass next_log_block += count_tags(journal, bh) // According to journal_tag_bytes(), 'tag_bytes' calculating is // affected by jbd2_has_feature_csum3(), jbd2_has_feature_csum3() // returns false because 'j->j_format_version >= 2' is not true, // then we get wrong next_log_block. The do_one_pass may exit // early whenoccuring non JBD2_MAGIC_NUMBER in 'next_log_block'. The filesystem is corrupted here, journal is partially replayed, and new journal sequence number actually is already used by last mounting. The invalidate_bdev() can drop all buffer heads even racing with bare reading block device(eg. systemd-udev), so we can fix it by invalidating bdev in error handling path in __ext4_fill_super(). Fetch a reproducer in [Link]. Link: https://bugzilla.kernel.org/show_bug.cgi?id=217171 Cc: Signed-off-by: Zhihao Cheng --- fs/ext4/super.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 88f7b8a88c76..7e990637bc48 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -1126,6 +1126,12 @@ static void ext4_blkdev_remove(struct ext4_sb_info *sbi) struct block_device *bdev; bdev = sbi->s_journal_bdev; if (bdev) { + /* + * Invalidate the journal device's buffers. We don't want them + * floating about in memory - the physical journal device may + * hotswapped, and it breaks the `ro-after' testing code. + */ + invalidate_bdev(bdev); ext4_blkdev_put(bdev); sbi->s_journal_bdev = NULL; } @@ -1271,14 +1277,8 @@ static void ext4_put_super(struct super_block *sb) sync_blockdev(sb->s_bdev); invalidate_bdev(sb->s_bdev); - if (sbi->s_journal_bdev && sbi->s_journal_bdev != sb->s_bdev) { - /* - * Invalidate the journal device's buffers. We don't want them - * floating about in memory - the physical journal device may - * hotswapped, and it breaks the `ro-after' testing code. - */ + if (sbi->s_journal_bdev) { sync_blockdev(sbi->s_journal_bdev); - invalidate_bdev(sbi->s_journal_bdev); ext4_blkdev_remove(sbi); } @@ -5610,6 +5610,7 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb) brelse(sbi->s_sbh); ext4_blkdev_remove(sbi); out_fail: + invalidate_bdev(sb->s_bdev); sb->s_fs_info = NULL; return err ? err : ret; } -- 2.31.1