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Date:   Thu, 24 Sep 2020 10:06:13 +0200
From:   Jan Kara <jack@suse.cz>
To:     Zhang Xiaoxu <zhangxiaoxu5@huawei.com>
Cc:     yi.zhang@huawei.com, tytso@mit.edu, jack@suse.cz,
        linux-ext4@vger.kernel.org, adilger.kernel@dilger.ca
Subject: Re: [PATCH] ext4: Fix bdev write error check failed when mount fs
 with ro
Message-ID: <20200924080613.GC27019@quack2.suse.cz>
References: <20200924011149.1624846-1-zhangxiaoxu5@huawei.com>
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On Wed 23-09-20 21:11:49, Zhang Xiaoxu wrote:
> If some errors has occurred on the device, and the orphan list not empty,
> then mount the device with 'ro', the bdev write error check will failed:
>   ext4_check_bdev_write_error:193: comm mount: Error while async write back metadata
> 
> Since the sbi->s_bdev_wb_err wouldn't be initialized when mount file system
> with 'ro', when clean up the orphan list and access the iloc buffer, bdev
> write error check will failed.
> 
> So we should always initialize the sbi->s_bdev_wb_err even if mount the
> file system with 'ro'.
> 
> Fixes: bc71726c7257 ("ext4: abort the filesystem if failed to async write metadata buffer")
> Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>

Thanks for the patch! Good catch! I just think you should now remove the
errseq_check_and_advance() call in ext4_remount() because it isn't needed
anymore.

								Honza


> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index ea425b49b345..086439889869 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -4814,9 +4814,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
>  	 * used to detect the metadata async write error.
>  	 */
>  	spin_lock_init(&sbi->s_bdev_wb_lock);
> -	if (!sb_rdonly(sb))
> -		errseq_check_and_advance(&sb->s_bdev->bd_inode->i_mapping->wb_err,
> -					 &sbi->s_bdev_wb_err);
> +	errseq_check_and_advance(&sb->s_bdev->bd_inode->i_mapping->wb_err,
> +				 &sbi->s_bdev_wb_err);
>  	sb->s_bdev->bd_super = sb;
>  	EXT4_SB(sb)->s_mount_state |= EXT4_ORPHAN_FS;
>  	ext4_orphan_cleanup(sb, es);
> -- 
> 2.25.4
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR