From f6f901fa6d2f27a6a309505c9d56a7cb81dd2453 Mon Sep 17 00:00:00 2001
From: Ayush Singh <ayush@beagleboard.org>
Date: Fri, 9 Jan 2026 12:24:02 +0530
Subject: [PATCH] std: sys: fs: uefi: Implement File::{flush, *sync}

- Make flush a noop since it is only for buffered writers.
- Also forward fsync to datasync. UEFI does not have anything
  separate for metadata sync.

Signed-off-by: Ayush Singh <ayush@beagleboard.org>
---
 library/std/src/sys/fs/uefi.rs | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/library/std/src/sys/fs/uefi.rs b/library/std/src/sys/fs/uefi.rs
index b1e5f33b1b22e..3fec1ee9ae138 100644
--- a/library/std/src/sys/fs/uefi.rs
+++ b/library/std/src/sys/fs/uefi.rs
@@ -285,11 +285,11 @@ impl File {
     }
 
     pub fn fsync(&self) -> io::Result<()> {
-        unsupported()
+        self.datasync()
     }
 
     pub fn datasync(&self) -> io::Result<()> {
-        unsupported()
+        self.0.flush()
     }
 
     pub fn lock(&self) -> io::Result<()> {
@@ -348,8 +348,9 @@ impl File {
         false
     }
 
+    // Write::flush is only meant for buffered writers. So should be noop for unbuffered files.
     pub fn flush(&self) -> io::Result<()> {
-        unsupported()
+        Ok(())
     }
 
     pub fn seek(&self, _pos: SeekFrom) -> io::Result<u64> {
@@ -744,6 +745,12 @@ mod uefi_fs {
             if r.is_error() { Err(io::Error::from_raw_os_error(r.as_usize())) } else { Ok(()) }
         }
 
+        pub(crate) fn flush(&self) -> io::Result<()> {
+            let file_ptr = self.protocol.as_ptr();
+            let r = unsafe { ((*file_ptr).flush)(file_ptr) };
+            if r.is_error() { Err(io::Error::from_raw_os_error(r.as_usize())) } else { Ok(()) }
+        }
+
         pub(crate) fn path(&self) -> &Path {
             &self.path
         }