Re: [PATCH v3] ext4: fix bug for rename with RENAME_WHITEOUT

Amir Goldstein
2021-01-22T20:35:53Z

On Fri, Jan 22, 2021 at 9:21 PM harshad shirwadkar
<harshadshirwadkar@gmail.com> wrote:
>
> Thanks Amir for pointing that out. Yes we are missing fast commit
> tracking in whiteout. I'll send out a fix for that.
>
> > But I must say it would have been very hard to catch missing ext4_fc_track_*
> > without specialized fs fuzzer such as the CrashMonkey generated tests.
>
> I agree, it's been on my to-do list to run CrashMonkey tests with fast
> commits. I'm curious what kind of CrashMonkey tests you ran that
> helped you catch this? Were you running Overlayfs on top of Ext4 with
> fast commits?
>

Neither. I just guessed RENAME_WHITEOUT might be missed as
developers are rarely aware of it.
I never ran CrashMonkey tests myself.
I found a few crash consistency bugs using xfstest generic/455.
I suggest that you run it with fast commits
and try using NUM_OPS and NUM_FILES larger than the test defaults
to let the test run for a longer time.

Thanks,
Amir.