Re: trying to understand how the /boot/loader symlink is supposed to work.

[Colin Walters <walters verbum org>]

On Mon, Feb 5, 2018, at 8:48 AM, Daniel Drake wrote:
> On Fri, Feb 2, 2018 at 2:14 PM, Colin Walters <walters verbum org> wrote:
> > I could imagine doing something like this with a "pre-grubx64.efi" binary
> > or the like whose sole purpose was to iterate over an available set of
> > grubx64-1.efi, grubx64-2.efi etc. which had .checksum files available too,
> > and if the checksum didn't match it was skipped or so.
>
> The idea being that we would first rename the current bootloader to
> grubx64-2 before then installing the new one as grubx64-1? And if it
> gets interrupted in the process we would rely on it falling back to
> grubx64-2?

Right.

> That might have some benefift but we would just end up with the same
> problem for the smaller pre-grubx64 bootloader  - how could we safely
> update that when it changes?

Yeah, the Universal Computer Science Solution here
of adding a layer of indirection only pushes the problem away partially.

> As an alternative, I wonder if UEFI variables can be updated
> atomically, allowing us to install the bootloader in a new path and
> only update the UEFI boot configuration to point to it once we're
> comfortable that the fs has been fully synced.

Yeah, I chatted with the grub2 maintainer about something like that
but I don't think we really fleshed it out.

In the big picture I personally am unlikely to work on this area anytime
soon, but maybe just post releases of your bootloader updater here
so there's more opportunity to collaborate?