On Do, 14.06.18 14:20, Chris Murphy (lists(a)colorremedies.com) wrote:
The cited BLS spec is the original one, not the more thoroughly
discussed and thought through variant by Matthew Garrett [1] some
years ago.
Quite frankly, as one of the authors of the original BLS spec, I can'd
say Matthew's version was much discussed with me...
I mean, I am open to extending the spec, but we should do this bit by
bit.
Zbigniew suggested to move the spec into docbook or markdown format,
and then accept changes via usual github PRs. If there's interest
still in extending the spec with some of Matthew's ideas we can
certainly look into that, but in general I'd actually prefer to reduce
the size of the spec if possible, and drop as many bits of it as we
can, i.e. the stuff noone implements anyway.
The cited BLS spec requires $BOOT be VFAT, are we doing that?
Why would we? I mean the idea is that $BOOT can be shared among
multiple OSes installed. Which means one really should settle on a
format anyone can read. And VFAT certainly qualifies as that, most
other file systems do not.
Are we going to stop doing the diabolical (and widespread) nested
mount nonsense, e.g. /boot/efi? Are we getting rid of the persistent
mounting of these volumes in favor of mounting/unmounting dynamically
only by the programs that are authorized to make changes to these
volumes?
So, in systemd we ship a generator that automatically establishes
automount points for the ESP. It will preferably use /efi as mount
point if it exists and is empty. If it doesn't exist or isn't
empty it will use /boot — if that exists or is empty. If neither exist
or are empty it won't do anything. Using an automount point for this
has many benefits:
1) The chance that the ESP remains in a clean state is maximized, as
the file system is unmounted whenever possible, and only mounted
for a short time window around actual disk accesses. This is the
behaviour you really want for something as fragile as the ESP.
2) It's compatible with current behaviour, as the path is always
accessible under a fixed name, requiring no explicit mounting.
3) There's no need to configure any lines for the ESP in /etc/fstab
anymore. Instead the system will discover the ESP automatically and
make it available. This means the installer can be simpler, and
things are generally more robust as /efi (or /boot) will follow
what is in place, instead of require a separate layer of
configuration that has a good chance of getting out of sync.
I'd love to see Fedora adopt this generator. Primarily this would mean
some chnages to anaconda I guess. It would make things simpler and
more robust. That said, the generator only cares about the ESP, not
for cases where $BOOT is backed by any other partition.
See systemd-gpt-auto-generator(8) for details about all of this.
Lennart
--
Lennart Poettering, Red Hat