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