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From: Amir Goldstein <amir73il@gmail.com>
To: Zhihao Cheng <chengzhihao1@huawei.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>,
	overlayfs <linux-unionfs@vger.kernel.org>,
	Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [QUESTION] Why overlayfs cannot mounted as nfs_export and metacopy?
Date: Sat, 7 Aug 2021 14:05:15 +0300	[thread overview]
Message-ID: <CAOQ4uxiO7zt7sywNqyd-WwCVds9-NqRAixham9yVeN7F+JhXoA@mail.gmail.com> (raw)
In-Reply-To: <ec78de1b-4edb-1eea-5c0d-79e65f139d79@huawei.com>

On Sat, Aug 7, 2021 at 1:17 PM Zhihao Cheng <chengzhihao1@huawei.com> wrote:
>
> Hi, all.
>
> As title said. I wonder to know the reason for overlayfs mount failure
> with '-o nfs_export=on,metacopy=on'.
>
> I modified kernel to enable these two options 'on',  it looks like that
> overlayfs can still work fine under nfs_v4.
>
> Besides, I can get no more information about the reason from source
> code, maybe I missed something.
>

It's because ovl_obtain_alias() (decoding a disconnected non-dir file handle)
does not know how to construct a metacopy overlayfs inode.

Maybe Vivek will be able to point you to the discussion that lead to making
the features mutually exclusive.

I don't remember any other reason.

Thanks,
Amir.

  reply	other threads:[~2021-08-07 11:05 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-07 10:17 [QUESTION] Why overlayfs cannot mounted as nfs_export and metacopy? Zhihao Cheng
2021-08-07 11:05 ` Amir Goldstein [this message]
2021-08-07 16:37   ` Amir Goldstein
2021-08-09  9:21     ` Zhihao Cheng
2021-08-09 21:35     ` Vivek Goyal
2021-08-10  4:17       ` Amir Goldstein
2021-08-10 19:48         ` Vivek Goyal
2021-08-10 20:00           ` Vivek Goyal
2021-08-11  6:51           ` Amir Goldstein
2021-08-16 18:27             ` Vivek Goyal
2021-08-16 18:44               ` Amir Goldstein
2021-08-16 19:00                 ` Vivek Goyal
2021-08-09 19:56   ` Vivek Goyal

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