On 2021-10-02, Vagrant Cascadian wrote: > On 2021-02-15, Vieno Hakkerinen wrote: >> I created a ext2 for /boot and luks+lvm+btrfs for /. As d-i defaults >> to use a @rootfs subvolume for btrfs the linux bootargs need to have >> set "rootflags=subvol=@rootfs". This was not set during configuration >> of flash-kernel. Without this argument debian failed to boot with an >> error that no init was found. > >> * What outcome did you expect instead? >> >> debian-installer should set "rootflags=subvol=@rootfs" in >> /etc/default/flash-kernel when btrfs is used for / > >> * What did you do to solve the problem? >> >> 1. I ran "setenv bootargs rootflags=subvol=@rootfs" in u-boot >> 2. I ran "boot" in u-boot >> 3. debian found init successfully >> 4. I added "rootflags=subvol=@rootfs" to LINUX_KERNEL_CMDLINE_DEFAULTS in >> /etc/default/flash-kernel >> 5. I ran flash-kernel >> 6. I rebooted >> 7. debian booted successfully > > So, flash-kernel-installer has a debconf question that might be useable > for this purpose: > > flash-kernel-installer.postinst.in:echo flash-kernel > flash-kernel/linux_cmdline string $kopt_params | \ > flash-kernel-installer.postinst.in- chroot /target debconf-set-selections > > I'm curious how other systems handle btrfs (e.g. grub on amd64); are > there any configuration options passed via debian-installer to set > "rootflags=subvol=@rootfs", or does grub have any configuration that are > set from update-grub or whatever ... or autodetected when rootfs is on > btrfs?
To answer my own question, looks like it's autodetected in
/etc/grub.d/10_linux:
case x"$GRUB_FS" in
xbtrfs)
rootsubvol="`make_system_path_relative_to_its_root /`"
rootsubvol="${rootsubvol#/}"
if [ "x${rootsubvol}" != x ]; then
GRUB_CMDLINE_LINUX="rootflags=subvol=${rootsubvol}
${GRUB_CMDLINE_LINUX}"
fi;;
I suspect the way to handle this would be to have flash-kernel-installer
do something similar and pass it into the debconf option ... unless
someone can find a sane place to put that into flash-kernel at
run-time...
It might be easier to adapt other code, such as u-boot-menu and install
u-boot-menu instead of, or in addition to, flash-kernel... or at least,
that would be another case where this could be supported.
live well,
vagrant
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