In XFS, the system would end up in unbootable state if an abrupt power
off after grub-install is occuring. It can be easily reproduced with.
grub-install /dev/vda; reboot -f
The grub error would show many different kinds of corruption in
filesystem and the problem boils down to incompleted journal transaction
which would leave pending writes behind in the on-disk journal. It is
therefore necessary to recover the system via re-mounting the filesystem
from linux system that all pending journal log can be replayed.