fuser-ng

fuser-ng is a higher-level, path-oriented FUSE filesystem library for Rust, built on top of fuser 0.17.

It started as a fork of fuse-mt. Version 0.7 updates the crate for fuser 0.17, uses fuser's native threading instead of an internal thread pool, and adds a new inode table that keeps descendant paths correct when a parent directory is renamed.

Overview

fuser exposes low-level FUSE kernel operations. fuser-ng wraps those operations with an API that is closer to the FUSE C API and simpler to implement for path-based filesystems.

The crate:

translates FUSE inodes into paths;
lets Filesystem methods return std::io::Result values instead of using fuser reply objects directly;
provides default ENOSYS implementations for operations you do not support;
simplifies readdir by handling FUSE pagination internally;
uses fuser's threaded event loop, configurable with ThreadCount;
adds broader unit and integration test coverage than the original fuse-mt codebase, including inode-table rename cases and passthrough FUSE operations.

Path API

Filesystem methods receive path-oriented types instead of raw inode numbers:

EntryName is a child name resolved relative to a parent directory. It is used for operations such as mkdir, create, unlink, and rename.
ResolvedPath is an existing entry path with its inode attached. It is used for operations such as open, read, write, and getattr.
FolderPath is the shared path stored for a directory.

The inode table stores complete paths for directories and derives leaf paths from their parent directories. This keeps descendants consistent after a directory subtree is renamed.

Usage

Add the crate to your Cargo.toml:

[dependencies]
fuser-ng = "0.7"

Implement fuser_ng::Filesystem, then wrap it before mounting:

let options = [fuser_ng::MountOption::FSName("myfs".into())];

fuser_ng::mount(
    fuser_ng::FuserNG::new(filesystem),
    mountpoint,
    &options,
    fuser_ng::ThreadCount::Default,
)?;

Passthrough example

The workspace includes a passthrough filesystem that forwards operations to another directory:

cargo run -p passthrufs -- <target> <mountpoint>
fusermount3 -u <mountpoint>

Testing

cargo test --workspace
cargo clippy --workspace --tests

Status

This crate is a work in progress. Version 0.7 is a breaking update from the old fuse-mt API. Bug reports, pull requests, and feedback are welcome.

License

Licensed under either MIT or Apache-2.0.

fuser-ng 0.7.0