system reconfigure: rename-file: invalid cross-device link

[Kenny Ballou]

Hello fellow Guix'ers,

I'm encountering a new error sometime after 
[[https://git.savannah.gnu.org/cgit/guix.git/commit/?id=28bc0e870b4d48b8e3e773382bb0e999df2e3611][28bc0e870b4d48b8]].

The elided output for the error:

#+begin_example
building /gnu/store/fmhhk62qagcg8jjfk6m2wzsnw8gyi6a0-switch-to-system.scm.drv...
making '/var/guix/profiles/system-79-link' the current system...
setting up setuid programs in '/run/setuid-programs'...
populating /etc from /gnu/store/jv2b1lgw3q2nhq6jl242c3vwh6s8szcj-etc...
guix system: error: rename-file: Invalid cross-device link
#+end_example

I have not had issues until trying to upgrade recently.  I don't believe my
configuration is all that exotic.  However, I do leverage several partitions
for each of the main mount points.  Namely, I have a 1GB root partition, with
additional partitions for ~/gnu~, ~/var~, ~/home~, etc.  The details can be 
seen in
my [[https://git.sr.ht/~kennyballou/dotfiles.git/][dotfiles]], specifically: 
[[https://git.sr.ht/~kennyballou/dotfiles.git/tree/master/item/systems/axo.scm][systems/axo.scm]].

Notice, this does not appear to affect home configurations, as I was able to
reconfigure/switch generations for my home configuration 
([[https://git.sr.ht/~kennyballou/dotfiles.git/tree/master/item/homes/axo.scm][homes/axo.scm]]).

I first noticed this issue in commit 
[[https://git.savannah.gnu.org/cgit/guix.git/commit/?id=4d994f98a49e1a6e58b9b0b512a05efc1c431a50][4d994f98a49e1a6e58b9b0b512a05efc1c431a50]].
I haven't tried to bisect to see if there's an immediate culprit due to time.
Before I do that, I'm reaching out to see if anyone here may know what is
happening.

Any help is greatly appreciated.

-- 
Kenny