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From: Carl Karsten <carl@nextdayvideo.com>
To: linux-unionfs@vger.kernel.org
Subject: Re: sd .img partition loop support
Date: Mon, 18 Oct 2021 13:45:46 -0500	[thread overview]
Message-ID: <CADmzSSgZqrBCavL=NmO1_YPCHP7DfG9hLnN4gNBXZXyJTo8XiQ@mail.gmail.com> (raw)
In-Reply-To: <CADmzSSgquwg49GfMNSxi6KRcvq2nxPhwtiH311D+Ux_VTuE+fA@mail.gmail.com>

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

code to replicate:

mkdir boot
cd boot
mkdir img  lower  upper work merged

wget http://downloads.raspberrypi.org/raspios_lite_armhf/images/raspios_lite_armhf-2020-05-28/2020-05-27-raspios-buster-lite-armhf.zip
unzip 2020-05-27-raspios-buster-lite-armhf.zip

sudo kpartx -av 2020-05-27-raspios-buster-lite-armhf.img
sudo mount /dev/mapper/loop0p1 img

# this errors:
sudo mount -t overlay overlay -olowerdir=img,upperdir=upper,workdir=work
merged

# this does not
cp img/* lower/
sudo mount -t overlay overlay -olowerdir=lower,upperdir=upper,workdir=work
merged

https://github.com/CarlFK/pici/blob/main/test1.sh

The goal is to netboot a pi using the files from the .img with a few
changes, the root kernel parameter needs to be changed from local storage
to nfs:
# tftp/cmdline.txt
root=/dev/nfs nfsroot=10.21.0.1:/srv/nfs/rpi/root,vers=4.1,proto=tcp rw
ip=dhcp rootwait elevator=deadline consoleblank=0

I can copy all the files from the .img into a dir,  but I am thinking I
should be able to overlay a dir on top to manage the changes.

If you want to see my netboot pi server setup
https://github.com/CarlFK/pici/blob/main/setup.md

--
Carl K

       reply	other threads:[~2021-10-18 18:46 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 ` Carl Karsten [this message]
2021-10-19  6:53   ` sd .img partition loop support Amir Goldstein
2021-10-19 15:29     ` Carl Karsten

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