[PATCH v2 0/8] Binary Large Objects for Rust DebugFS

Danilo Krummrich
2025-10-20T22:27:44Z

This series adds support for exposing binary large objects via Rust debugfs.

The first two patches extend UserSliceReader and UserSliceWriter with partial
read/write helpers.

The series further introduces read_binary_file(), write_binary_file() and
read_write_binary_file() methods for the Dir and ScopedDir types.

It also introduces the BinaryWriter and BinaryReader traits, which are used to
read/write the implementing type's binary representation with the help of the
backing file operations from/to debugfs.

Additional to some more generic blanked implementations for the BinaryWriter and
BinaryReader traits it also provides implementations for common smart pointer
types.

Both samples (file-based and scoped) are updated with corresponding examples.

A branch containing the patches can be found in [1].

[1] https://git.kernel.org/pub/scm/linux/kernel/git/dakr/linux.git/log/?h=debugfs_blobs

Changes in v2:
- Add file::Offset type alias.
- uaccess:
- Saturate at buffer length on offset overflow.
- Use file::Offset instead of usize.
- debugfs:
- Use file::Offset instead of usize.
- Handle potential overflow when updating ppos.
- Use &T::FILE_OPS directly if possible.
- Fix safety comment in BinaryReaderMut::read_from_slice_mut().

Danilo Krummrich (8):
rust: fs: add file::Offset type alias
rust: uaccess: add UserSliceReader::read_slice_partial()
rust: uaccess: add UserSliceWriter::write_slice_partial()
rust: debugfs: support for binary large objects
rust: debugfs: support blobs from smart pointers
samples: rust: debugfs: add example for blobs
rust: debugfs: support binary large objects for ScopedDir
samples: rust: debugfs_scoped: add example for blobs

rust/kernel/debugfs.rs | 110 +++++++++++++++-
rust/kernel/debugfs/file_ops.rs | 145 ++++++++++++++++++++-
rust/kernel/debugfs/traits.rs | 190 +++++++++++++++++++++++++++-
rust/kernel/fs/file.rs | 5 +
rust/kernel/uaccess.rs | 49 +++++++
samples/rust/rust_debugfs.rs | 13 ++
samples/rust/rust_debugfs_scoped.rs | 14 +-
7 files changed, 515 insertions(+), 11 deletions(-)

base-commit: 340ccc973544a6e7e331729bc4944603085cafab
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2.51.0