From: Wedson Almeida Filho <walmeida@xxxxxxxxxxxxx>
This series introduces Rust abstractions that allow page-cache-backed read-only
file systems to be written in Rust.
There are two file systems that are built on top of these abstractions: tarfs
and puzzlefs. The former has zero unsafe blocks and is included as a patch in
this series; the latter is described elsewhere [1]. We limit the functionality
to the bare minimum needed to implement them.
Rust file system modules can be declared with the `module_fs` macro and are
required to implement the following functions (which are part of the
`FileSystem` trait):
impl FileSystem for MyFS {
fn super_params(sb: &NewSuperBlock<Self>) -> Result<SuperParams<Self::Data>>;
fn init_root(sb: &SuperBlock<Self>) -> Result<ARef<INode<Self>>>;
fn read_dir(inode: &INode<Self>, emitter: &mut DirEmitter) -> Result;
fn lookup(parent: &INode<Self>, name: &[u8]) -> Result<ARef<INode<Self>>>;
fn read_folio(inode: &INode<Self>, folio: LockedFolio<'_>) -> Result;
}
They can optionally implement the following:
fn read_xattr(inode: &INode<Self>, name: &CStr, outbuf: &mut [u8]) -> Result<usize>;
fn statfs(sb: &SuperBlock<Self>) -> Result<Stat>;
They may also choose the type of the data they can attach to superblocks and/or
inodes.
There a couple of issues that are likely to lead to unsoundness that have to do
with the unregistration of file systems. I will send separate emails about
them.
A git tree is available here:
git://github.com/wedsonaf/linux.git vfs
Web:
https://github.com/wedsonaf/linux/commits/vfs
[1]: The PuzzleFS container filesystem: https://lwn.net/Articles/945320/
Wedson Almeida Filho (19):
rust: fs: add registration/unregistration of file systems
rust: fs: introduce the `module_fs` macro
samples: rust: add initial ro file system sample
rust: fs: introduce `FileSystem::super_params`
rust: fs: introduce `INode<T>`
rust: fs: introduce `FileSystem::init_root`
rust: fs: introduce `FileSystem::read_dir`
rust: fs: introduce `FileSystem::lookup`
rust: folio: introduce basic support for folios
rust: fs: introduce `FileSystem::read_folio`
rust: fs: introduce `FileSystem::read_xattr`
rust: fs: introduce `FileSystem::statfs`
rust: fs: introduce more inode types
rust: fs: add per-superblock data
rust: fs: add basic support for fs buffer heads
rust: fs: allow file systems backed by a block device
rust: fs: allow per-inode data
rust: fs: export file type from mode constants
tarfs: introduce tar fs
fs/Kconfig | 1 +
fs/Makefile | 1 +
fs/tarfs/Kconfig | 16 +
fs/tarfs/Makefile | 8 +
fs/tarfs/defs.rs | 80 ++
fs/tarfs/tar.rs | 322 +++++++
rust/bindings/bindings_helper.h | 13 +
rust/bindings/lib.rs | 6 +
rust/helpers.c | 142 ++++
rust/kernel/error.rs | 6 +-
rust/kernel/folio.rs | 214 +++++
rust/kernel/fs.rs | 1290 +++++++++++++++++++++++++++++
rust/kernel/fs/buffer.rs | 60 ++
rust/kernel/lib.rs | 2 +
rust/kernel/mem_cache.rs | 2 -
samples/rust/Kconfig | 10 +
samples/rust/Makefile | 1 +
samples/rust/rust_rofs.rs | 154 ++++
scripts/generate_rust_analyzer.py | 2 +-
19 files changed, 2324 insertions(+), 6 deletions(-)
create mode 100644 fs/tarfs/Kconfig
create mode 100644 fs/tarfs/Makefile
create mode 100644 fs/tarfs/defs.rs
create mode 100644 fs/tarfs/tar.rs
create mode 100644 rust/kernel/folio.rs
create mode 100644 rust/kernel/fs.rs
create mode 100644 rust/kernel/fs/buffer.rs
create mode 100644 samples/rust/rust_rofs.rs
base-commit: b0bc357ef7a98904600826dea3de79c0c67eb0a7
--
2.34.1
