Inner mutability improvements

src/fs.rs

@@ -72,6 +72,19 @@ pub struct Allocation<Storage: driver::Storage> {
     state: ll::lfs_t,
 }
 
+/// # Safety
+///
+/// All operations are done on `&mut Allocation, and the reference is held
+/// during the entire lifetime of the filesystem, so once the reference is
+/// available again, the filesystem is closed
+unsafe impl<Storage: driver::Storage> Sync for Allocation<Storage> {}
+/// # Safety
+///
+/// All operations are done on `&mut Allocation, and the reference is held
+/// during the entire lifetime of the filesystem, so once the reference is
+/// available again, the filesystem is closed
+unsafe impl<Storage: driver::Storage> Send for Allocation<Storage> {}
+
 // pub fn check_storage_requirements(
 
 impl<Storage: driver::Storage> Default for Allocation<Storage> {
@@ -803,7 +816,7 @@ impl OpenOptions {
     pub unsafe fn open<'a, 'b, S: driver::Storage>(
         &self,
         fs: &'b Filesystem<'a, S>,
-        alloc: &mut FileAllocation<S>,
+        alloc: &'b mut FileAllocation<S>,
         path: &Path,
     ) -> Result<File<'a, 'b, S>> {
         alloc.config.buffer = alloc.cache.get() as *mut _;
@@ -1544,4 +1557,21 @@ mod tests {
         })
         .unwrap();
     }
+
+    #[allow(unreachable_code)]
+    fn _filesystem_is_sync() {
+        fn assert_is_sync<T: Sync, R>(_: &T) -> R {
+            todo!()
+        }
+        fn assert_is_send<T: Send, R>(_: &T) -> R {
+            todo!()
+        }
+
+        assert_is_sync::<Allocation<TestStorage>, ()>(todo!());
+        assert_is_send::<&mut Allocation<TestStorage>, ()>(todo!());
+        assert_is_send::<RefCell<&mut Allocation<TestStorage>>, ()>(todo!());
+
+        let mut test_storage = TestStorage::new();
+        Filesystem::mount_and_then(&mut test_storage, |fs| assert_is_send(fs)).unwrap()
+    }
 }