Hi Abhishek,
It looks like readlink_copy is no longer exported (it was prior to 4.7).

I would guess you'd need to do something similar to this, ie: use the
i_op->readlink function instead.
https://marc.info/?l=linux-xfs&m=142981614925048&w=2

Regards,
Andre

On Fri, 17 Nov 2017 at 20:54 Abhishek Joshi <abjoshi@cs.stonybrook.edu>
wrote:

> Hi,
> With linux kernel version 4.10.0-38-generic, when I compile yaffs2 as an
> out of tree module, I get the following warning:
>
> *WARNING: "readlink_copy"
> [/home/abjoshi/workspace/cse523/yaffs2/yaffs2multi.ko] undefined!*
> I did a bit of digging and found that '*readlink_copy'* is used in
> yaffs_readlink when the kernel version is greater than 3.15 and is in fact,
> not exported which explains the warning, I think.
> I believe I am missing something here, module obviously cannot have
> undefined symbols. Is this a kernel version problem? Any help is greatly
> appreciated.
>
> My compilation steps:
>  - git clone
>  - make
>
>
> --
> Thanks and Regards,
> Abhishek Joshi
>
>
>
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