From 28f31300525b2ee18cb77df0796fa5a83e5b8ac9 Mon Sep 17 00:00:00 2001
From: Felix Obenhuber <felix.obenhuber@esrlabs.com>
Date: Thu, 27 May 2021 08:46:36 +0200
Subject: [PATCH 1/2] Implement `AsRawFd` and `IntoRawFd` for LoopControl and
 LoopDevice

Getting the raw fd of loop control can be neccecary because the
`next_free` and `attach` operation is (unfortunately) not atomic. The fd
can be used to acquire a `flock`.

Add `IntoRawFd` for LoopDevice.
---
 src/lib.rs | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/src/lib.rs b/src/lib.rs
index ff8eec0..a52eaf4 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -86,6 +86,18 @@ impl LoopControl {
     }
 }
 
+impl AsRawFd for LoopControl {
+    fn as_raw_fd(&self) -> RawFd {
+        self.dev_file.as_raw_fd()
+    }
+}
+
+impl IntoRawFd for LoopControl {
+    fn into_raw_fd(self) -> RawFd {
+        self.dev_file.into_raw_fd()
+    }
+}
+
 /// Interface to a loop device ie `/dev/loop0`.
 #[derive(Debug)]
 pub struct LoopDevice {
@@ -98,6 +110,12 @@ impl AsRawFd for LoopDevice {
     }
 }
 
+impl IntoRawFd for LoopDevice {
+    fn into_raw_fd(self) -> RawFd {
+        self.device.into_raw_fd()
+    }
+}
+
 impl LoopDevice {
     /// Opens a loop device.
     pub fn open<P: AsRef<Path>>(dev: P) -> io::Result<Self> {

From 546d63449f9b5116ed967d55fabae46340d58d0a Mon Sep 17 00:00:00 2001
From: Felix Obenhuber <felix.obenhuber@esrlabs.com>
Date: Thu, 27 May 2021 08:49:02 +0200
Subject: [PATCH 2/2] Add `metadata` for a `LoopDevice`

Getting the `Metadata` is usefull to access the major/minor number of
the device that is needed when using the loopdev in combination with
device-mapper.
---
 src/lib.rs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/lib.rs b/src/lib.rs
index a52eaf4..4821f79 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -22,9 +22,9 @@ use bindings::{
     loop_info64, LOOP_CLR_FD, LOOP_CTL_GET_FREE, LOOP_SET_CAPACITY, LOOP_SET_FD, LOOP_SET_STATUS64,
 };
 use libc::{c_int, ioctl};
-use std::fs::{File, OpenOptions};
 use std::{
     default::Default,
+    fs::{File, Metadata, OpenOptions},
     io,
     os::unix::prelude::*,
     path::{Path, PathBuf},
@@ -263,6 +263,11 @@ impl LoopDevice {
         std::fs::read_link(&p).ok()
     }
 
+    /// Get the device metadata
+    pub fn metadata(&self) -> io::Result<Metadata> {
+        self.device.metadata()
+    }
+
     /// Detach a loop device from its backing file.
     ///
     /// Note that the device won't fully detach until a short delay after the underling device file