On Wed, Jul 26, 2023 at 7:58 PM Ariel Miculas <amiculas@xxxxxxxxx> wrote: > > This allows us to create a Vfsmount structure and pass it to the read > callback. > > Signed-off-by: Ariel Miculas <amiculas@xxxxxxxxx> > --- > rust/kernel/file.rs | 17 +++++++++++++++-- > samples/rust/puzzlefs.rs | 40 +++++++++++++++++++++++++++++++++++----- > samples/rust/rust_fs.rs | 3 ++- > 3 files changed, 52 insertions(+), 8 deletions(-) > > diff --git a/rust/kernel/file.rs b/rust/kernel/file.rs > index a3002c416dbb..af1eb1ee9267 100644 > --- a/rust/kernel/file.rs > +++ b/rust/kernel/file.rs > @@ -457,9 +457,15 @@ impl<A: OpenAdapter<T::OpenData>, T: Operations> OperationsVtable<A, T> { > // `fileref` never outlives this function, so it is guaranteed to be > // valid. > let fileref = unsafe { File::from_ptr(file) }; > + > + // SAFETY: into_foreign was called in fs::NewSuperBlock<..., NeedsInit>::init and > + // it is valid until from_foreign will be called in fs::Tables::free_callback > + let fs_info = > + unsafe { <T::Filesystem as fs::Type>::Data::borrow((*(*inode).i_sb).s_fs_info) }; > + > // SAFETY: `arg` was previously returned by `A::convert` and must > // be a valid non-null pointer. > - let ptr = T::open(unsafe { &*arg }, fileref)?.into_foreign(); > + let ptr = T::open(fs_info, unsafe { &*arg }, fileref)?.into_foreign(); > // SAFETY: The C contract guarantees that `private_data` is available > // for implementers of the file operations (no other C code accesses > // it), so we know that there are no concurrent threads/CPUs accessing > @@ -930,10 +936,17 @@ pub trait Operations { > /// The type of the context data passed to [`Operations::open`]. > type OpenData: Sync = (); > > + /// Data associated with each file system instance. > + type Filesystem: fs::Type; > + > /// Creates a new instance of this file. > /// > /// Corresponds to the `open` function pointer in `struct file_operations`. > - fn open(context: &Self::OpenData, file: &File) -> Result<Self::Data>; > + fn open( > + fs_info: <<Self::Filesystem as fs::Type>::Data as ForeignOwnable>::Borrowed<'_>, > + context: &Self::OpenData, > + file: &File, > + ) -> Result<Self::Data>; > > /// Cleans up after the last reference to the file goes away. > /// > diff --git a/samples/rust/puzzlefs.rs b/samples/rust/puzzlefs.rs > index 9afd82745b64..8a64e0bd437d 100644 > --- a/samples/rust/puzzlefs.rs > +++ b/samples/rust/puzzlefs.rs > @@ -3,8 +3,14 @@ > //! Rust file system sample. > > use kernel::module_fs; > +use kernel::mount::Vfsmount; > use kernel::prelude::*; > -use kernel::{c_str, file, fs, io_buffer::IoBufferWriter}; > +use kernel::{ > + c_str, file, fmt, fs, > + io_buffer::IoBufferWriter, > + str::CString, > + sync::{Arc, ArcBorrow}, > +}; > > mod puzzle; > // Required by the autogenerated '_capnp.rs' files > @@ -19,6 +25,12 @@ > > struct PuzzleFsModule; > > +#[derive(Debug)] > +struct PuzzlefsInfo { > + base_path: CString, > + vfs_mount: Arc<Vfsmount>, > +} > + > #[vtable] > impl fs::Context<Self> for PuzzleFsModule { > type Data = (); > @@ -46,14 +58,23 @@ fn try_new() -> Result { > impl fs::Type for PuzzleFsModule { > type Context = Self; > type INodeData = &'static [u8]; > + type Data = Box<PuzzlefsInfo>; > const SUPER_TYPE: fs::Super = fs::Super::Independent; > const NAME: &'static CStr = c_str!("puzzlefs"); > const FLAGS: i32 = fs::flags::USERNS_MOUNT; > const DCACHE_BASED: bool = true; > > fn fill_super(_data: (), sb: fs::NewSuperBlock<'_, Self>) -> Result<&fs::SuperBlock<Self>> { > + let base_path = CString::try_from_fmt(fmt!("hello world"))?; > + pr_info!("base_path {:?}\n", base_path); > + let vfs_mount = Vfsmount::new_private_mount(c_str!("/home/puzzlefs_oci"))?; > + pr_info!("vfs_mount {:?}\n", vfs_mount); > + > let sb = sb.init( > - (), > + Box::try_new(PuzzlefsInfo { > + base_path, > + vfs_mount: Arc::try_new(vfs_mount)?, > + })?, > &fs::SuperParams { > magic: 0x72757374, > ..fs::SuperParams::DEFAULT > @@ -88,14 +109,23 @@ fn fill_super(_data: (), sb: fs::NewSuperBlock<'_, Self>) -> Result<&fs::SuperBl > > #[vtable] > impl file::Operations for FsFile { > + // must be the same as INodeData > type OpenData = &'static [u8]; > + type Filesystem = PuzzleFsModule; > + // this is an Arc because Data must be ForeignOwnable and the only implementors of it are Box, > + // Arc and (); we cannot pass a reference to read, so we share Vfsmount using and Arc > + type Data = Arc<Vfsmount>; > > - fn open(_context: &Self::OpenData, _file: &file::File) -> Result<Self::Data> { > - Ok(()) > + fn open( > + fs_info: &PuzzlefsInfo, > + _context: &Self::OpenData, > + _file: &file::File, > + ) -> Result<Self::Data> { > + Ok(fs_info.vfs_mount.clone()) > } > > fn read( > - _data: (), > + data: ArcBorrow<'_, Vfsmount>, > file: &file::File, > writer: &mut impl IoBufferWriter, > offset: u64, > diff --git a/samples/rust/rust_fs.rs b/samples/rust/rust_fs.rs > index 7527681ee024..c58ed1560e06 100644 > --- a/samples/rust/rust_fs.rs > +++ b/samples/rust/rust_fs.rs > @@ -85,8 +85,9 @@ fn fill_super(_data: (), sb: fs::NewSuperBlock<'_, Self>) -> Result<&fs::SuperBl > #[vtable] > impl file::Operations for FsFile { > type OpenData = &'static [u8]; > + type Filesystem = RustFs; > > - fn open(_context: &Self::OpenData, _file: &file::File) -> Result<Self::Data> { > + fn open(_fs_info: (), _context: &Self::OpenData, _file: &file::File) -> Result<Self::Data> { > Ok(()) > } > > -- > 2.41.0 > > Hey Wedson, Is it ok to couple file::Operations with fs::Type? I didn't find a better way to implement this. I'm asking because I've seen you've gone to great lengths to decouple them. Cheers, Ariel