> It results in a grub.cfg line like:
> linux /root/boot/vmlinuz-4.2.0-1-amd64
root=UUID=d430d7ee-8059-11e5-9834-502690aa641f ro rootflags=subvol=root
rootflags=degraded
> and apparently the 2nd rootflags= is simply ignored.
My tests shows that first "rootflags" is ignored, and the second one
matters:
root@pegaz# cat /boot/grub/grub.cfg | egrep subvol | head -n1
linux /pegaz/boot/vmlinuz-4.19.0-14-amd64
root=UUID=ea6ae51d-d9b0-4628-a8f3-3406e1dc59c6 ro rootflags=subvol=pegaz
rootflags=space_cache=v2 quiet
This one is iginored:
rootflags=subvol=pegaz
and this one takes effect:
rootflags=space_cache=v2
so default subvolume is mounted instead of "pegaz" subvolume.
This is severe and can change how system boots.
My workaround is to put whole rootflags in /etc/default/grub:
root@pegaz:~# egrep rootflags= /etc/default/grub
GRUB_CMDLINE_LINUX="rootflags=clear_cache,space_cache=v2,subvol=pegaz"
root@pegaz:~# egrep rootflags= /boot/grub/grub.cfg | head -n1
linux /pegaz/boot/vmlinuz-4.19.0-14-amd64
root=UUID=ea6ae51d-d9b0-4628-a8f3-3406e1dc59c6 ro rootflags=subvol=pegaz
rootflags=clear_cache,space_cache=v2,subvol=pegaz quiet
This is ignored:
rootflags=subvol=pegaz
and this takes effect:
rootflags=clear_cache,space_cache=v2,subvol=pegaz
