Re: [PATCH v7 08/24] erofs: add namei functions

From: Pavel Machek
Date: Thu Aug 15 2019 - 03:01:39 EST


Hi!

> > > + /*
> > > + * on-disk error, let's only BUG_ON in the debugging mode.
> > > + * otherwise, it will return 1 to just skip the invalid name
> > > + * and go on (in consideration of the lookup performance).
> > > + */
> > > + DBG_BUGON(qd->name > qd->end);
> >
> > I believe you should check for errors in non-debug mode, too.
>
> Thanks for your kindly reply!
>
> The following is just my personal thought... If I am wrong, please
> kindly point out...
>
> As you can see, this is a new prefixed string binary search algorithm
> which can provide similar performance with hashed approach (but no
> need to store hash value at all), so I really care about its lookup
> performance.
>
> There is something needing to be concerned, is, whether namei() should
> report any potential on-disk issues or just return -ENOENT for these
> corrupted dirs, I think I tend to use the latter one.

-ENOENT is okay for corrupted directories, as long as corrupted
directories do not cause some kind of security bugs (memory
corruption, crashes, ...)


Best regards,
Pavel
--
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

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