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To:     <miklos@szeredi.hu>, <amir73il@gmail.com>,
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From:   Zhihao Cheng <chengzhihao1@huawei.com>
Subject: [QUESTION] Why overlayfs cannot mounted as nfs_export and metacopy?
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Date:   Sat, 7 Aug 2021 18:17:02 +0800
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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.