chore(tvix): move store/fs to castore/fs r/7256

With the recent introduction of the RootNodes trait, there's nothing in
the fs module pulling in tvix-store dependencies, so it can live in
tvix-castore.

This allows other crates to make use of TvixStoreFS, without having to
pull in tvix-store.

For example, a tvix-build using a fuse mountpoint at /nix/store doesn't
need a PathInfoService to hold the root nodes that should be present,
but just a list.

tvix-store now has a pathinfoservice/fs module, which contains the
necessary glue logic to implement the RootNodes trait for a
PathInfoService.

To satisfy Rust orphan rules for trait implementations, we had to add a
small wrapper struct. It's mostly hidden away by the make_fs helper
function returning a TvixStoreFs.

It can't be entirely private, as its still leaking into the concrete
type of TvixStoreFS.

tvix-store still has `fuse` and `virtiofs` features, but they now simply
enable these features in the `tvix-castore` crate they depend on.

The tests for the fuse functionality stay in tvix-store for now, as
they populate the root nodes through a PathInfoService.

Once above mentioned "list of root nodes" implementation exists, we
might want to shuffle this around one more time.

Fixes b/341.

Change-Id: I989f664827a5a361b23b34368d242d10c157c756
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10378
Autosubmit: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>

1 files changed, 9 insertions, 8 deletions

diff --git a/tvix/Cargo.lock b/tvix/Cargo.lock
index 297adf5c84..2f04f037a7 100644
--- a/tvix/Cargo.lock
+++ b/tvix/Cargo.lock
@@ -3108,9 +3108,12 @@ dependencies = [
  "bstr",
  "bytes",
  "data-encoding",
+ "fuse-backend-rs",
  "futures",
  "hex-literal",
  "lazy_static",
+ "libc",
+ "parking_lot 0.12.1",
  "pin-project-lite",
  "prost",
  "prost-build",
@@ -3128,6 +3131,12 @@ dependencies = [
  "tower",
  "tracing",
  "url",
+ "vhost",
+ "vhost-user-backend",
+ "virtio-bindings 0.2.1",
+ "virtio-queue",
+ "vm-memory",
+ "vmm-sys-util",
  "walkdir",
 ]
 
@@ -3233,12 +3242,10 @@ dependencies = [
  "clap",
  "count-write",
  "data-encoding",
- "fuse-backend-rs",
  "futures",
  "lazy_static",
  "libc",
  "nix-compat",
- "parking_lot 0.12.1",
  "pin-project-lite",
  "prost",
  "prost-build",
@@ -3261,12 +3268,6 @@ dependencies = [
  "tracing-subscriber",
  "tvix-castore",
  "url",
- "vhost",
- "vhost-user-backend",
- "virtio-bindings 0.2.1",
- "virtio-queue",
- "vm-memory",
- "vmm-sys-util",
  "walkdir",
  "xz2",
 ]