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, 46 insertions, 0 deletions

diff --git a/tvix/castore/Cargo.toml b/tvix/castore/Cargo.toml
index 2a421280b82b..0f0146972969 100644
--- a/tvix/castore/Cargo.toml
+++ b/tvix/castore/Cargo.toml
@@ -10,6 +10,7 @@ bytes = "1.4.0"
 data-encoding = "2.3.3"
 futures = "0.3.28"
 lazy_static = "1.4.0"
+parking_lot = "0.12.1"
 pin-project-lite = "0.2.13"
 prost = "0.12.1"
 sled = { version = "0.34.7" }
@@ -25,10 +26,42 @@ walkdir = "2.4.0"
 bstr = "1.6.0"
 async-tempfile = "0.4.0"
 
+[dependencies.fuse-backend-rs]
+optional = true
+version = "0.11.0"
+
+[dependencies.libc]
+optional = true
+version = "0.2.144"
+
 [dependencies.tonic-reflection]
 optional = true
 version = "0.10.2"
 
+[dependencies.vhost]
+optional = true
+version = "0.6"
+
+[dependencies.vhost-user-backend]
+optional = true
+version = "0.8"
+
+[dependencies.virtio-queue]
+optional = true
+version = "0.7"
+
+[dependencies.vm-memory]
+optional = true
+version = "0.10"
+
+[dependencies.vmm-sys-util]
+optional = true
+version = "0.11"
+
+[dependencies.virtio-bindings]
+optional = true
+version = "0.2.1"
+
 [build-dependencies]
 prost-build = "0.12.1"
 tonic-build = "0.10.2"
@@ -41,4 +74,17 @@ hex-literal = "0.4.1"
 
 [features]
 default = []
+fs = ["dep:libc", "dep:fuse-backend-rs"]
+virtiofs = [
+  "fs",
+  "dep:vhost",
+  "dep:vhost-user-backend",
+  "dep:virtio-queue",
+  "dep:vm-memory",
+  "dep:vmm-sys-util",
+  "dep:virtio-bindings",
+  "fuse-backend-rs?/vhost-user-fs", # impl FsCacheReqHandler for SlaveFsCacheReq
+  "fuse-backend-rs?/virtiofs",
+]
+fuse = ["fs"]
 tonic-reflection = ["dep:tonic-reflection"]