Re: [PATCH v2 1/5] ext4: Fix reusing stale buffer heads from last failed mounting

[Zhihao Cheng <chengzhihao1@huawei.com>]

在 2023/3/14 19:33, Jan Kara 写道:
Hi Jan,

> 
>> @@ -1271,14 +1277,8 @@ static void ext4_put_super(struct super_block *sb)
>>   
>>   	sync_blockdev(sb->s_bdev);
>>   	invalidate_bdev(sb->s_bdev);

For journal in the inode case, journal bhs come from block device, which 
means buffers will be dropped after this line 
'invalidate_bdev(sb->s_bdev)' being executed.

>> -	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);
>>   	}
>  > Hum, but this will invalidate bhs only if journal is stored on a block
> device. If journal is in the inode (the common case), we won't invalidate
> anything (sbi->s_journal_bdev is NULL) and the same problem can happen?
>