Restrict auto-fcntl to non-v2 schemes.

src/scheme/root.rs

@@ -74,6 +74,12 @@ impl KernelScheme for RootScheme {
                 let path_box = path.to_string().into_boxed_str();
                 let mut schemes = scheme::schemes_mut();
 
+                let v2 = flags & O_FSYNC == O_FSYNC;
+
+                if !v2 {
+                    //log::warn!("Context {} opened a v1 scheme", context::current().read().name);
+                }
+
                 let (_scheme_id, inner) =
                     schemes.insert_and_pass(self.scheme_ns, path, |scheme_id| {
                         let inner = Arc::new(UserInner::new(
@@ -81,7 +87,7 @@ impl KernelScheme for RootScheme {
                             scheme_id,
                             // TODO: This is a hack, but eventually the legacy interface will be
                             // removed.
-                            flags & O_FSYNC == O_FSYNC,
+                            v2,
                             id,
                             path_box,
                             flags,

src/scheme/user.rs

@@ -1533,11 +1533,12 @@ impl KernelScheme for UserScheme {
         call_flags: u32,
         stored_flags: u32,
     ) -> Result<usize> {
-        if call_flags != stored_flags {
+        let inner = self.inner.upgrade().ok_or(Error::new(ENODEV))?;
+
+        if call_flags != stored_flags && !inner.v2 {
             self.fcntl(file, F_SETFL, call_flags as usize)?;
         }
 
-        let inner = self.inner.upgrade().ok_or(Error::new(ENODEV))?;
         let mut address = inner.capture_user(buf)?;
         let result = inner.call(
             Opcode::Read,
@@ -1552,7 +1553,7 @@ impl KernelScheme for UserScheme {
         );
         address.release()?;
 
-        if call_flags != stored_flags {
+        if call_flags != stored_flags && !inner.v2 {
             self.fcntl(file, F_SETFL, stored_flags as usize)?;
         }
 
@@ -1567,11 +1568,11 @@ impl KernelScheme for UserScheme {
         call_flags: u32,
         stored_flags: u32,
     ) -> Result<usize> {
-        if call_flags != stored_flags {
+        let inner = self.inner.upgrade().ok_or(Error::new(ENODEV))?;
+        if call_flags != stored_flags && !inner.v2 {
             self.fcntl(file, F_SETFL, call_flags as usize)?;
         }
 
-        let inner = self.inner.upgrade().ok_or(Error::new(ENODEV))?;
         let mut address = inner.capture_user(buf)?;
         let result = inner.call(
             Opcode::Write,
@@ -1586,7 +1587,7 @@ impl KernelScheme for UserScheme {
         );
         address.release()?;
 
-        if call_flags != stored_flags {
+        if call_flags != stored_flags && !inner.v2 {
             self.fcntl(file, F_SETFL, stored_flags as usize)?;
         }