Merge pull request thesofproject#26 from adamrk/add-fsync

Add fsync file operation

rust/kernel/src/file_operations.rs

@@ -140,6 +140,29 @@ unsafe extern "C" fn llseek_callback<T: FileOperations>(
  }
 }
 
+unsafe extern "C" fn fsync_callback<T: FileOperations>(
+ file: *mut bindings::file,
+ start: bindings::loff_t,
+ end: bindings::loff_t,
+ datasync: c_types::c_int,
+) -> c_types::c_int {
+ let start = match start.try_into() {
+ Ok(v) => v,
+ Err(_) => return Error::EINVAL.to_kernel_errno(),
+ };
+ let end = match end.try_into() {
+ Ok(v) => v,
+ Err(_) => return Error::EINVAL.to_kernel_errno(),
+ };
+ let datasync = datasync != 0;
+ let fsync = T::FSYNC.unwrap();
+ let f = &*((*file).private_data as *const T);
+ match fsync(f, &File::from_ptr(file), start, end, datasync) {
+ Ok(result) => result.try_into().unwrap(),
+ Err(e) => e.to_kernel_errno(),
+ }
+}
+
 pub(crate) struct FileOperationsVtable<T>(marker::PhantomData<T>);
 
 impl<T: FileOperations> FileOperationsVtable<T> {
@@ -170,7 +193,11 @@ impl<T: FileOperations> FileOperationsVtable<T> {
  fasync: None,
  flock: None,
  flush: None,
- fsync: None,
+ fsync: if let Some(_) = T::FSYNC {
+ Some(fsync_callback::<T>)
+ } else {
+ None
+ },
  get_unmapped_area: None,
  iterate: None,
  iterate_shared: None,
@@ -195,6 +222,7 @@ impl<T: FileOperations> FileOperationsVtable<T> {
 pub type ReadFn<T> = Option<fn(&T, &File, &mut UserSlicePtrWriter, u64) -> KernelResult<()>>;
 pub type WriteFn<T> = Option<fn(&T, &mut UserSlicePtrReader, u64) -> KernelResult<()>>;
 pub type SeekFn<T> = Option<fn(&T, &File, SeekFrom) -> KernelResult<u64>>;
+pub type FSync<T> = Option<fn(&T, &File, u64, u64, bool) -> KernelResult<u32>>;
 
 /// `FileOperations` corresponds to the kernel's `struct file_operations`. You
 /// implement this trait whenever you'd create a `struct file_operations`.
@@ -216,4 +244,8 @@ pub trait FileOperations: Sync + Sized {
  /// Changes the position of the file. Corresponds to the `llseek` function
  /// pointer in `struct file_operations`.
  const SEEK: SeekFn<Self> = None;
+
+ /// Syncs pending changes to this file. Corresponds to the `fsync` function 
+ /// pointer in the `struct file_operations`.
+ const FSYNC: FSync<Self> = None;
 }