diff --git a/common/src/writer.rs b/common/src/writer.rs
index f871a9b9e..8056b11d8 100644
--- a/common/src/writer.rs
+++ b/common/src/writer.rs
@@ -65,7 +65,7 @@ pub struct AntiCallToken(());
 ///
 /// Thread-safety is enforced at the call sites that require it.
 pub trait TerminatingWrite: Write {
-    /// Indicates that the writer will no longer be used. Internally calls `terminate_ref`.
+    /// Indicate that the writer will no longer be used. Internally call terminate_ref.
     fn terminate(mut self) -> io::Result<()>
     where Self: Sized {
         self.terminate_ref(AntiCallToken(()))
@@ -84,9 +84,7 @@ impl<W: TerminatingWrite + ?Sized> TerminatingWrite for Box<W> {
 
 impl<W: TerminatingWrite> TerminatingWrite for BufWriter<W> {
     fn terminate_ref(&mut self, a: AntiCallToken) -> io::Result<()> {
-        if !self.buffer().is_empty() {
-            self.flush()?;
-        }
+        self.flush()?;
         self.get_mut().terminate_ref(a)
     }
 }
diff --git a/src/directory/directory.rs b/src/directory/directory.rs
index 46b3c669f..9e3a7b14d 100644
--- a/src/directory/directory.rs
+++ b/src/directory/directory.rs
@@ -139,15 +139,21 @@ pub trait Directory: DirectoryClone + fmt::Debug + Send + Sync + 'static {
     /// Opens a writer for the *virtual file* associated with
     /// a [`Path`].
     ///
-    /// Depending on the directory implementation, [`Directory::sync_directory()`] may be required
-    /// after terminating the writer to ensure that the file is durably created.
+    /// After the writer is terminated, the file should be created and any subsequent call to
+    /// [`Directory::open_read()`] for the same path should return a [`FileSlice`].
     ///
-    /// Write operations may be aggressively buffered. The client must call
-    /// [`TerminatingWrite::terminate()`] to finalize the file and make all writes available to
-    /// subsequent reads. The directory implementation owns its buffering strategy; clients should
-    /// not rely on `flush()` making an incomplete file available.
+    /// However, depending on the directory implementation,
+    /// it might be required to call [`Directory::sync_directory()`] to ensure
+    /// that the file is durably created.
+    /// (The semantics here are the same when dealing with
+    /// a POSIX filesystem.)
     ///
-    /// The user shall not rely on [`Drop`] finalizing the file.
+    /// Write operations may be aggressively buffered.
+    /// The client of this trait is responsible for calling terminate
+    /// to ensure that subsequent `read` operations
+    /// will take into account preceding `write` operations.
+    ///
+    /// The user shall not rely on [`Drop`] triggering terminate.
     ///
     /// The file may not previously exist.
     fn open_write(&self, path: &Path) -> Result<WritePtr, OpenWriteError>;
diff --git a/src/directory/footer.rs b/src/directory/footer.rs
index d2ff52f9a..bffa2f2cf 100644
--- a/src/directory/footer.rs
+++ b/src/directory/footer.rs
@@ -126,9 +126,9 @@ impl Footer {
 }
 
 pub(crate) struct FooterProxy<W: TerminatingWrite> {
-    /// Always `Some` except after `terminate()` is called.
+    /// always Some except after terminate call
     hasher: Option<Hasher>,
-    /// Always `Some` except after `terminate()` is called.
+    /// always Some except after terminate call
     writer: Option<W>,
 }
 
diff --git a/src/directory/mmap_directory/mod.rs b/src/directory/mmap_directory/mod.rs
index 061a4ca5f..1c33f0358 100644
--- a/src/directory/mmap_directory/mod.rs
+++ b/src/directory/mmap_directory/mod.rs
@@ -318,7 +318,8 @@ impl Drop for ReleaseLockFile {
     }
 }
 
-/// Wraps a file and syncs its data when the writer is terminated.
+/// This Write wraps a File, but has the specificity of
+/// calling `sync_all` on terminate.
 struct SafeFileWriter(File);
 
 impl SafeFileWriter {
diff --git a/src/directory/ram_directory.rs b/src/directory/ram_directory.rs
index 87b5b46a9..bfa3d0ecb 100644
--- a/src/directory/ram_directory.rs
+++ b/src/directory/ram_directory.rs
@@ -60,7 +60,7 @@ impl Drop for MemoryUsageTracker {
 
 /// Writer associated with the [`RamDirectory`].
 ///
-/// The writer stores its buffer in the directory when terminated.
+/// The Writer just writes a buffer.
 struct VecWriter {
     path: PathBuf,
     shared_directory: RamDirectory,
@@ -109,8 +109,6 @@ impl Write for VecWriter {
         Ok(buf.len())
     }
 
-    /// Nothing to flush since the data is stored in memory. The memory usage is updated on each
-    /// write.
     fn flush(&mut self) -> io::Result<()> {
         Ok(())
     }
diff --git a/src/fastfield/alive_bitset.rs b/src/fastfield/alive_bitset.rs
index ed2f8dfe8..bbdc82a45 100644
--- a/src/fastfield/alive_bitset.rs
+++ b/src/fastfield/alive_bitset.rs
@@ -8,7 +8,7 @@ use crate::DocId;
 /// Write an alive `BitSet`
 ///
 /// where `alive_bitset` is the set of alive `DocId`.
-/// Warning: this function does not call `terminate()`. The caller is in charge of
+/// Warning: this function does not call terminate. The caller is in charge of
 /// closing the writer properly.
 pub fn write_alive_bitset<T: Write>(alive_bitset: &BitSet, writer: &mut T) -> io::Result<()> {
     alive_bitset.serialize(writer)?;
diff --git a/src/positions/serializer.rs b/src/positions/serializer.rs
index 617033909..f41923e8b 100644
--- a/src/positions/serializer.rs
+++ b/src/positions/serializer.rs
@@ -86,8 +86,8 @@ impl<W: io::Write> PositionSerializer<W> {
         Ok(())
     }
 
-    /// Close the positions for this field.
-    pub fn close(self) -> io::Result<()> {
-        Ok(())
+    /// Close the positions for this term and flushes the data.
+    pub fn close(mut self) -> io::Result<()> {
+        self.positions_wrt.flush()
     }
 }