I was thinking a bit more recently about the "live" changes
stuff https://github.com/coreos/rpm-ostree/issues/639
(particularly since https://github.com/coreos/rpm-ostree/pull/2060 )
and I realized reading the last debates in that issue that
there's really a much simpler solution; do exactly the same
thing we do for `ostree admin unlock`, except mount it read-only
by default.
Then, anything that wants to modify it does the same thing
libostree does for `/sysroot` and `/boot` as of recently; create
a new mount namespace and do the modifications there.
The advantages of this are numerous. First, we already have
all of the code, it's basically just plumbing through a new
entry in the state enumeration and passing `MS_RDONLY` into
the `mount()` system call.
"live" changes here also naturally don't persist, unlike what
we are currently doing in rpm-ostree.
Follow the precedent set in https://github.com/coreos/rpm-ostree/pull/2106
and rename the directory, to more clearly move away from the
"uninstalled" test model. Prep for Rust-based tests.
Colin Walters