This series introduces Rust abstractions that allow read-only file systems to
be written in Rust.
There are three file systems implementations using these abstractions
abstractions: ext2, tarfs, and puzzlefs. The first two are part of this series.
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):
fn fill_super(
sb: &mut SuperBlock<Self, sb::New>,
mapper: Option<inode::Mapper>,
) -> Result<Self::Data>;
fn init_root(sb: &SuperBlock<Self>) -> Result<dentry::Root<Self>>;
They can optionally implement the following:
fn read_xattr(
_dentry: &DEntry<Self>,
_inode: &INode<Self>,
_name: &CStr,
_outbuf: &mut [u8],
) -> Result<usize>;
fn statfs(_dentry: &DEntry<Self>) -> Result<Stat>;
They may also choose the type of the data they can attach to superblocks and/or
inodes.
Lastly, file systems can implement inode, file, and address space operations
and attach them to inodes when they're created, similar to how C does it. They
can get a ro address space operations table from an implementation of iomap
operations, to be used with generic ro file operations.
A git tree is available here:
git://github.com/wedsonaf/linux.git vfs-v2
Web:
https://github.com/wedsonaf/linux/commits/vfs-v2
---
Changes in v2:
- Rebased to latest rust-next tree
- Removed buffer heads
- Added iomap support
- Removed `_pin` field from `Registration` as it's not needed anymore
- Renamed sample filesystem to match the module's name
- Using typestate instead of a separate type for superblock/new-superblock
- Created separate submodules for superblocks, inodes, dentries, and files
- Split out operations from FileSystem to inode/file/address_space ops, similar to how C does it
- Removed usages of folio_set_error
- Removed UniqueFolio, for now reading blocks from devices via the pagecache
- Changed map() to return the entire folio if not in highmem
- Added support for unlocking the folio asynchronously
- Added `from_raw` to all new ref-counted types
- Added explicit types in calls to cast()
- Added typestate to folio
- Added support for implementing get_link
- Fixed data race when reading inode->i_state
- Added nofs scope support during allocation
- Link to v1: https://lore.kernel.org/rust-for-linux/20231018122518.128049-1-wedsonaf@xxxxxxxxx/
---
Wedson Almeida Filho (30):
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::fill_super`
rust: fs: introduce `INode<T>`
rust: fs: introduce `DEntry<T>`
rust: fs: introduce `FileSystem::init_root`
rust: file: move `kernel::file` to `kernel::fs::file`
rust: fs: generalise `File` for different file systems
rust: fs: add empty file operations
rust: fs: introduce `file::Operations::read_dir`
rust: fs: introduce `file::Operations::seek`
rust: fs: introduce `file::Operations::read`
rust: fs: add empty inode operations
rust: fs: introduce `inode::Operations::lookup`
rust: folio: introduce basic support for folios
rust: fs: add empty address space operations
rust: fs: introduce `address_space::Operations::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: allow file systems backed by a block device
rust: fs: allow per-inode data
rust: fs: export file type from mode constants
rust: fs: allow populating i_lnk
rust: fs: add `iomap` module
rust: fs: add memalloc_nofs support
tarfs: introduce tar fs
WIP: fs: ext2: add rust ro ext2 implementation
fs/Kconfig | 2 +
fs/Makefile | 2 +
fs/rust-ext2/Kconfig | 13 +
fs/rust-ext2/Makefile | 8 +
fs/rust-ext2/defs.rs | 173 +++++++
fs/rust-ext2/ext2.rs | 551 +++++++++++++++++++++
fs/tarfs/Kconfig | 15 +
fs/tarfs/Makefile | 8 +
fs/tarfs/defs.rs | 80 +++
fs/tarfs/tar.rs | 394 +++++++++++++++
rust/bindings/bindings_helper.h | 11 +
rust/helpers.c | 182 +++++++
rust/kernel/block.rs | 10 +-
rust/kernel/error.rs | 8 +-
rust/kernel/file.rs | 251 ----------
rust/kernel/folio.rs | 305 ++++++++++++
rust/kernel/fs.rs | 492 +++++++++++++++++++
rust/kernel/fs/address_space.rs | 90 ++++
rust/kernel/fs/dentry.rs | 136 ++++++
rust/kernel/fs/file.rs | 607 +++++++++++++++++++++++
rust/kernel/fs/inode.rs | 780 ++++++++++++++++++++++++++++++
rust/kernel/fs/iomap.rs | 281 +++++++++++
rust/kernel/fs/sb.rs | 194 ++++++++
rust/kernel/lib.rs | 6 +-
rust/kernel/mem_cache.rs | 2 -
rust/kernel/user.rs | 1 -
samples/rust/Kconfig | 10 +
samples/rust/Makefile | 1 +
samples/rust/rust_rofs.rs | 202 ++++++++
scripts/generate_rust_analyzer.py | 2 +-
30 files changed, 4555 insertions(+), 262 deletions(-)
create mode 100644 fs/rust-ext2/Kconfig
create mode 100644 fs/rust-ext2/Makefile
create mode 100644 fs/rust-ext2/defs.rs
create mode 100644 fs/rust-ext2/ext2.rs
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
delete mode 100644 rust/kernel/file.rs
create mode 100644 rust/kernel/folio.rs
create mode 100644 rust/kernel/fs.rs
create mode 100644 rust/kernel/fs/address_space.rs
create mode 100644 rust/kernel/fs/dentry.rs
create mode 100644 rust/kernel/fs/file.rs
create mode 100644 rust/kernel/fs/inode.rs
create mode 100644 rust/kernel/fs/iomap.rs
create mode 100644 rust/kernel/fs/sb.rs
create mode 100644 samples/rust/rust_rofs.rs
base-commit: 183ea65d1fcd71039cf4d111a22d69c337bfd344
--
2.34.1
