From 8c2794533dd69b4c77182385ae080130d8da35a1 Mon Sep 17 00:00:00 2001
From: Anatol Belski <anbelski@linux.microsoft.com>
Date: Wed, 11 Mar 2026 00:05:19 +0100
Subject: [PATCH] block: qcow: impl AsFd for RawFile and QcowRawFile

Implement AsFd for both RawFile and QcowRawFile by delegating to
the inner File handle. This enables safe fd borrowing through the
standard AsFd trait, which is a prerequisite for replacing unsafe
libc::dup calls with BorrowedFd::try_clone_to_owned().

Suggested-by: Rob Bradford <rbradford@rivosinc.com>
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
---
 block/src/qcow/qcow_raw_file.rs | 8 +++++++-
 block/src/qcow/raw_file.rs      | 7 +++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/block/src/qcow/qcow_raw_file.rs b/block/src/qcow/qcow_raw_file.rs
index 92a569d34..232f6b5a5 100644
--- a/block/src/qcow/qcow_raw_file.rs
+++ b/block/src/qcow/qcow_raw_file.rs
@@ -7,7 +7,7 @@
 use std::fmt::Debug;
 use std::io::{self, BufWriter, Read, Seek, SeekFrom, Write};
 use std::mem::size_of;
-use std::os::fd::{AsRawFd, RawFd};
+use std::os::fd::{AsFd, AsRawFd, BorrowedFd, RawFd};
 
 use byteorder::{BigEndian, ReadBytesExt, WriteBytesExt};
 use vmm_sys_util::write_zeroes::WriteZeroes;
@@ -361,3 +361,9 @@ impl AsRawFd for QcowRawFile {
         self.file.as_raw_fd()
     }
 }
+
+impl AsFd for QcowRawFile {
+    fn as_fd(&self) -> BorrowedFd<'_> {
+        self.file.as_fd()
+    }
+}
diff --git a/block/src/qcow/raw_file.rs b/block/src/qcow/raw_file.rs
index eda7751c3..06ec4975f 100644
--- a/block/src/qcow/raw_file.rs
+++ b/block/src/qcow/raw_file.rs
@@ -11,6 +11,7 @@
 use std::alloc::{Layout, alloc_zeroed, dealloc};
 use std::fs::{File, Metadata};
 use std::io::{self, Read, Seek, SeekFrom, Write};
+use std::os::fd::{AsFd, BorrowedFd};
 use std::os::unix::io::{AsRawFd, RawFd};
 use std::slice;
 
@@ -397,3 +398,9 @@ impl AsRawFd for RawFile {
         self.file.as_raw_fd()
     }
 }
+
+impl AsFd for RawFile {
+    fn as_fd(&self) -> BorrowedFd<'_> {
+        self.file.as_fd()
+    }
+}