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From: Richard Weinberger <richard@nod.at>
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Subject: Re: Regression in handling power cuts since 3a1e819b4e80 ("ovl: store file handle of lower inode on copy up")
Date: Sat, 20 Oct 2018 08:58:49 +0200
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Am Freitag, 19. Oktober 2018, 23:28:33 CEST schrieb Rafał Miłecki:
> On Fri, 19 Oct 2018 at 16:59, Richard Weinberger <richard@nod.at> wrote:
> > Am Freitag, 19. Oktober 2018, 16:45:53 CEST schrieb Richard Weinberger:
> > > Well, I fear it uncovers a problem in UBIFS. We had already problems with overlayfs.
> > > Did you bisect the problem and you are sure that the said commit is the first bad commit?
> >
> > Another thing, UBIFS has no export operations, so overlayfs will fall back to xattrs,
> > if I read the commit correctly.
> > Maybe this is the root of the problem.
> >
> > I'm currently traveling, so I cannot test much. Please make sure whether
> > 3a1e819b4e80 is really the first bad commit.
> > Then I can go for a bug hunt. :-)
> 
> I did another test and everything keeps pointing to the 3a1e819b4e80.
> 
> 1) I switched to the 4.12.14
> 2) I confirmed problem exists there
> 3) I added "return 0;" at the beginning of ovl_set_origin()
> 4) I confirmed problem disappeared

Okay. But I still think we're facing some UBIFS problem.

To double check, on Linux 4.12.14 the problem exists and by reverting 3a1e819b4e80 (or making it a nop)
it goes away?
Do you see the warning regarding the double orphan only in the bad case?

Thanks,
//richard