Re: [f2fs-dev] [PATCH] f2fs: fix to update dir's i_pino during cross_rename

[Chao Yu]

On 2019/11/8 1:05, Eric Biggers wrote:
> On Thu, Nov 07, 2019 at 02:12:05PM +0800, Chao Yu wrote:
>> As Eric reported:
>>
>> RENAME_EXCHANGE support was just added to fsstress in xfstests:
>>
>> 	commit 65dfd40a97b6bbbd2a22538977bab355c5bc0f06
>> 	Author: kaixuxia <xiakaixu1987@xxxxxxxxx>
>> 	Date:   Thu Oct 31 14:41:48 2019 +0800
>>
>> 	    fsstress: add EXCHANGE renameat2 support
>>
>> This is causing xfstest generic/579 to fail due to fsck.f2fs reporting errors.
>> I'm not sure what the problem is, but it still happens even with all the
>> fs-verity stuff in the test commented out, so that the test just runs fsstress.
>>
>> generic/579 23s ... 	[10:02:25]
>> [    7.745370] run fstests generic/579 at 2019-11-04 10:02:25
>> _check_generic_filesystem: filesystem on /dev/vdc is inconsistent
>> (see /results/f2fs/results-default/generic/579.full for details)
>>  [10:02:47]
>> Ran: generic/579
>> Failures: generic/579
>> Failed 1 of 1 tests
>> Xunit report: /results/f2fs/results-default/result.xml
>>
>> Here's the contents of 579.full:
>>
>> _check_generic_filesystem: filesystem on /dev/vdc is inconsistent
>> *** fsck.f2fs output ***
>> [ASSERT] (__chk_dots_dentries:1378)  --> Bad inode number[0x24] for '..', parent parent ino is [0xd10]
>>
>> The root cause is that we forgot to update directory's i_pino during
>> cross_rename, fix it.
>>
>> Fixes: 32f9bc25cbda0 ("f2fs: support ->rename2()")
>> Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
> 
> Tested-by: Eric Biggers <ebiggers@xxxxxxxxxx>

Thanks for the test.

> 
> The i_pino field is only valid on directories, right?

i_pino is also valid on regular inode, because after sudden power-cut case, we
will recover fsynced file and link it into parent directory which i_pino field
points.

For rename/cross_rename cases, we just tag src/dst regular inode with
parent_lost flag instead of updating its i_pino field, once there is fsync()
comes after rename(), we will trigger checkpoint for such parent lost inode to
keep rename/cross_rename operation as an atomic operation.

Thanks,

> 
> - Eric
> .
>