Bug#685530: Possibly nothing to deal with grub

[lionel]

Package: grub-common
Version: 2.00-22
Followup-For: Bug #685530

Dear Maintainer,

This possibly has nothing to deal with grub but with the way BTRFS works
with missing drives (if bug's responsible is using a btrfs only / and
/boot).

Where mdadm raid1 volumes are readable even if one componnent is
missing, Btrfs does not let the volume being mounted.
Administrator must edit the kernel command line at boot time and add something like :
rootflags=degraded

Then he can delete the failed drive, add another one, and start a "btrfs balance" on the filesystem.

Maybe Grub's scripts responsible of creating rescue mode entry can add this rootflags option when it
detects btrfs root ?