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Date: Wed, 10 Jan 2024 14:33:04 +0100
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Subject: Re: [0/4] overlayfs: Adjustments for ovl_fill_super()
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To: Amir Goldstein <amir73il@gmail.com>, linux-unionfs@vger.kernel.org,
 kernel-janitors@vger.kernel.org
Cc: Miklos Szeredi <miklos@szeredi.hu>, cocci@inria.fr,
 LKML <linux-kernel@vger.kernel.org>, Christian Brauner <brauner@kernel.org>
References: <6cbcf640-55e5-2f11-4a09-716fe681c0d2@web.de>
 <87b65f8e-abde-2aff-4da8-df6e0b464677@web.de>
 <05d334af-1a0f-4498-b57d-36a783288f07@web.de>
 <CAOQ4uxiRaTQyT1nxeRD7B89=VuA+KKEqi01LL1kqfJ17-qKKpw@mail.gmail.com>
 <d912872a-e70a-4e5d-aabe-26f289507f44@web.de>
 <CAOQ4uxjsuYy8BzgaHXaNa-S0+HZ_P-Fb1UEgOkbrdxQPz0Y6rQ@mail.gmail.com>
From: Markus Elfring <Markus.Elfring@web.de>
In-Reply-To: <CAOQ4uxjsuYy8BzgaHXaNa-S0+HZ_P-Fb1UEgOkbrdxQPz0Y6rQ@mail.gmail.com>
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>>>> See also:
>>>> https://lore.kernel.org/cocci/87b65f8e-abde-2aff-4da8-df6e0b464677@we=
b.de/
>>>> https://sympa.inria.fr/sympa/arc/cocci/2023-03/msg00115.html
>>>
>>> I will queue cleanup patches 1-2,
>>
>> Thanks for this positive feedback.
>
> Sorry, these patches do not apply to master branch and patch 1
> is no longer correct in master branch and the new mount api changes.

Do you want that I adapt the linked development ideas to the current situa=
tion
a bit more?


>>>                                   but I do not like patches 3/4 and 4/=
4.
>>> I do not think that they make the code better to read or maintain.
>>
>> I would appreciate if the details for such change reluctance can be cla=
rified better.
>
> patch 3:
> I much rather a single error handling label that takes care of
> all the cleanups - it is harder to make mistakes and jump to
> the wrong label when adding new error conditions.

There are different coding style preferences involved.

See also:
https://wiki.sei.cmu.edu/confluence/display/c/MEM12-C.+Consider+using+a+go=
to+chain+when+leaving+a+function+on+error+when+using+and+releasing+resourc=
es


> patch 4:
> Overlayfs uses this coding style all over the place
>
>   err =3D -ENOMEM;
>   ofs->creator_cred =3D cred =3D prepare_creds();
>   if (!cred)
>       goto out_free_ofs;
>
> I don't see the benefit in making err =3D -ENOMEM conditional.
> I don't see the style after your patch as clearly better than before.

Can it be nicer to set error codes only in exceptional data processing sit=
uations?

Regards,
Markus