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From: Amir Goldstein <amir73il@gmail.com>
To: Carl Karsten <carl@nextdayvideo.com>
Cc: overlayfs <linux-unionfs@vger.kernel.org>
Subject: Re: sd .img partition loop support
Date: Tue, 19 Oct 2021 09:53:33 +0300	[thread overview]
Message-ID: <CAOQ4uxizf9=arB8V7N_EtgsDrjO3XetKSCkQA3ErtwyovExkuA@mail.gmail.com> (raw)
In-Reply-To: <CADmzSSgZqrBCavL=NmO1_YPCHP7DfG9hLnN4gNBXZXyJTo8XiQ@mail.gmail.com>

On Mon, Oct 18, 2021 at 9:46 PM Carl Karsten <carl@nextdayvideo.com> wrote:
>
> I'm trying to overlay an empty upper dir onto a fat/loop/img fs and getting:
>
> juser@negk:~/boot$ sudo mount -o ro /dev/mapper/loop0p1 img
> juser@negk:~/boot$ sudo mount -t overlay overlay
> -olowerdir=img,upperdir=upper,workdir=work merged
> mount: /home/juser/boot/merged: wrong fs type, bad option, bad superblock
> on overlay, missing codepage or helper program, or other error.
>
> [ 2449.670177] overlayfs: filesystem on 'lower' not supported
>

fat was never supported as lower or upper layer AFAIK, see:
https://lore.kernel.org/linux-unionfs/2527352.xHhNOModH5@nerdopolis/

This is due to the case insensitive and special name encoding of fat.
It is not unfixable, but it was never a priority for anyone to fix it.

I suppose it would be easier for you to copy the image to another filesystem
before constructing the overlay.

Thanks,
Amir.

  reply	other threads:[~2021-10-19  6:53 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CADmzSSgquwg49GfMNSxi6KRcvq2nxPhwtiH311D+Ux_VTuE+fA@mail.gmail.com>
2021-10-18 18:45 ` sd .img partition loop support Carl Karsten
2021-10-19  6:53   ` Amir Goldstein [this message]
2021-10-19 15:29     ` Carl Karsten

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