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

From: Wu Bo
Date: Wed Aug 11 2021 - 22:55:31 EST



在 2021/8/11 20:57, Chao Yu 写道:
On 2021/8/11 11:28, Wu Bo wrote:

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

I didn't see this patch in 4.14 stable kernel of mailine, so do you mean 4.14 kernel
maintained by Android?

If so, f2fs codes in between 4.14 and 4.19 Android kernel are almost the same,
see below link:

https://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs-stable.git/


Sorry, it's our old Android project code.So the kernel version may have no reference value.
This project code last sync to Android common kernel is:
9f892496fc0b:f2fs: readahead encrypted block during GC[2018-09-05]
The code link is:
https://android.googlesource.com/kernel/common/+/9f892496fc0b
And after that, we applied some fixup patches.

Thanks,



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,



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