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Subject: Re: [PATCH] ext4: Fix bdev write error check failed when mount fs
 with ro
To:     Jan Kara <jack@suse.cz>
CC:     <yi.zhang@huawei.com>, <tytso@mit.edu>,
        <linux-ext4@vger.kernel.org>, <adilger.kernel@dilger.ca>
References: <20200924011149.1624846-1-zhangxiaoxu5@huawei.com>
 <20200924080613.GC27019@quack2.suse.cz>
From:   "zhangxiaoxu (A)" <zhangxiaoxu5@huawei.com>
Message-ID: <e4d35bb9-e83f-343f-10ff-7b19be6cb86b@huawei.com>
Date:   Thu, 24 Sep 2020 22:42:30 +0800
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?? 2020/9/24 16:06, Jan Kara д??:
> 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.

Thanks for your suggesstion.
I will send the v2 to remove the errseq_check_and_advance in ext4_remount.

Xiaoxu.
> 
> 
>> 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
>>