Fwd: Grub support for btrfs zstd compression?

[Colin Watson]

On Tue, Feb 23, 2021 at 07:47:16AM +0200, Tor-björn Claesson wrote:
> I hope this is the right venue for this question.
> 
> Does the current grub (2.04-15) support booting from a btrfs filesystem
> with zstd-compression?

In principle it should do; the relevant upstream commit seems to be
386128648606a3aa6ae7108d1c9af52258202279, which was part of 2.04.  I
have no direct experience with this, though.

> I recently installed debian testing to a root subvolume on zstd-compressed
> btrfs raid1, which failed to boot, citing inability to find drives
> belonging to the btrfs raid array. Disabling compression on /boot,
> /initrd.img and /vmlinuz, reinstalling the kernel package and rebuilding
> the initramfs fixed this.
> There was however another error generating the initramfs-image, which I
> fixed, but which confuses me as to the cause of my boot problems.
> 
> I looked through the changelog of grub-efi-amd64 but did not find a mention
> of cherry picking zstd-support. Does this mean it does not currently
> support booting off a zstd compressed btrfs volume and would you in this
> case like me to file a bug report? Trying to fix this, if desirable, would
> be a nice learning experience for me.

I don't know what the specific issue here might be; I don't think it's
just a missing cherry-pick, since I don't see any upstream commits since
2.04 that immediately seem relevant.  Feel free to file a bug with
details.

-- 
Colin Watson (he/him)                              [cjwatson at debian.org]