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Subject: Re: [PATCH] [REGRESSION] ovl: Handle ENOSYS when fileattr support is
 missing in lower/upper fs
From:   =?utf-8?Q?Christian_Kohlsch=C3=BCtter?= 
        <christian@kohlschutter.com>
In-Reply-To: <CAHk-=wg+bpP5cvcaBhnmJKzTmAtgx12UhR4qzFXXb52atn9gDw@mail.gmail.com>
Date:   Mon, 18 Jul 2022 22:33:48 +0200
Cc:     Miklos Szeredi <miklos@szeredi.hu>,
        overlayfs <linux-unionfs@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>
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To:     Linus Torvalds <torvalds@linux-foundation.org>
Precedence: bulk

> Am 18.07.2022 um 22:12 schrieb Linus Torvalds =
<torvalds@linux-foundation.org>:
>=20
> On Mon, Jul 18, 2022 at 12:28 PM Miklos Szeredi <miklos@szeredi.hu> =
wrote:
>>=20
>> So this is a bug in the kernel part of fuse, that doesn't catch and
>> convert ENOSYS in case of the ioctl request.
>=20
> Ahh, even better. No need to worry about external issues.
>=20
>            Linus

My concern was fixing it in fuse instead of ovl would leave non-fuse =
filesystems affected (even though I don't have proof that such =
filesystems exist).

I'm glad you are OK with Miklos' change; the outcome of this discussion =
certainly adds some nuance to the famous "don't break userspace" / error =
code thread from 2012.

Best,
Christian