linux-kernel - Re: [f2fs-dev] f2fs do DIO write make file corruption

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Date:   Wed, 11 Aug 2021 11:28:57 +0800
From:   Wu Bo <bo.wu@...o.com>
To:     Chao Yu <chao@...nel.org>, linux-kernel@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net
Subject: Re: [f2fs-dev] f2fs do DIO write make file corruption


在 2021/8/11 11:03, Chao Yu 写道:
> On 2021/8/11 10:48, Wu Bo wrote:
>> I use the following command to create a file, the file may got 
>> corruption:
>>     f2fs_io write 2 0 512 inc_num dio $path
>>
>> And when I use bio or to set the chunk size to 1 block, the file is
>> normal. The commands as following:
>>     f2fs_io write 2 0 512 inc_num buffered $path
>>     f2fs_io write 1 0 512 inc_num dio $path
>>
>> I find this bug on old kernel version 4.14.117, and not find on version
>> 4.19.152. So this bug is fixed. Can anyone can tell me which patch fixed
>> this bug?
> 
> Not sure,
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-4.19.y&id=7bae8b6b73e46c307fa355ce086800b7ad6610f8 
> 

This patch is applied. The issue occurs when f2fs dio try to preallocate 
multiple blocks and got scattered disk blocks. The log as following:
       my_f2fs_io-13425 [002] ....   395.583637: el0_irq_naked: 
1:type:1,ino:40132,off:768,old_blk:0,new_blk:185764
       my_f2fs_io-13425 [002] ....   395.583710: el0_irq_naked: 
1:type:1,ino:40132,off:769,old_blk:0,new_blk:205824
       my_f2fs_io-13425 [002] ....   395.583721: f2fs_map_blocks: dev = 
(259,23), ino = 40132, file offset = 768, start blkaddr = 0x2d5a4, len = 
0x2, err = 0
       my_f2fs_io-13425 [002] ....   395.583735: f2fs_map_blocks: dev = 
(259,23), ino = 40132, file offset = 768, start blkaddr = 0x2d5a4, len = 
0x1, err = 0
       my_f2fs_io-13425 [002] ....   395.583741: f2fs_map_blocks: dev = 
(259,23), ino = 40132, file offset = 769, start blkaddr = 0x32400, len = 
0x1, err = 0

And if the blocks are continuously, the file data is normal:
	  my_f2fs_io-13425 [002] ....   395.584037: el0_irq_naked: 
1:type:1,ino:40132,off:770,old_blk:0,new_blk:205825
       my_f2fs_io-13425 [002] ....   395.584066: el0_irq_naked: 
1:type:1,ino:40132,off:771,old_blk:0,new_blk:205826
       my_f2fs_io-13425 [002] ....   395.584077: f2fs_map_blocks: dev = 
(259,23), ino = 40132, file offset = 770, start blkaddr = 0x32401, len = 
0x2, err = 0
       my_f2fs_io-13425 [002] ....   395.584091: f2fs_map_blocks: dev = 
(259,23), ino = 40132, file offset = 770, start blkaddr = 0x32401, len = 
0x2, err = 0

> 
> Thanks,
> 
>>
>>
>> _______________________________________________
>> Linux-f2fs-devel mailing list
>> Linux-f2fs-devel@...ts.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
>>
>