GRUB fails to update correctly with BTRFS or ZFS on Bedrock Linux

[development]

First, I'm inexperienced with the mailing list and GRUB development processes. Let me know if I'm going about this correctly.

The Bedrock Linux project has been wrestling with a GRUB update issue. There is a Github issue[1] containing relevant info that I will summarize here.

The current theory is that, due to Bedrock's use of bind mounts on the root directory, /proc/self/mountinfo may contain multiple entries with identical major:minor numbers. This (we think) is causing grub-mkrelpath to choose the wrong one, leading to an incorrect boot configuration.

I intend to write a patch but want to gather whatever information I can before I take to programming.

Relevant links:

[1] https://github.com/bedrocklinux/bedrocklinux-userland/issues/200

[2] https://bedrocklinux.org/0.7/feature-compatibility.html#grub-btrfs-zfs

[3] https://github.com/bedrocklinux/bedrocklinux-userland/issues/190#issuecomment-664373262

[4] https://github.com/bedrocklinux/bedrocklinux-userland/issues/157

Possibly relevant bugs:

[5] https://savannah.gnu.org/bugs/?58270

[6] https://savannah.gnu.org/bugs/?51451

[7] https://savannah.gnu.org/bugs/?45902