agent: Fix the issues with bind volumes

The mount type should be considered as empty if the value is
`Some("none")`.

Fixes: kata-containers#10642

Signed-off-by: Xuewei Niu <[email protected]>

src/agent/rustjail/src/mount.rs

@@ -233,7 +233,7 @@ pub fn init_rootfs(
         // bind may be only specified in the oci spec options -> flags update r#type
         let m = &{
             let mut mbind = m.clone();
-            if mbind.typ().is_none() && flags & MsFlags::MS_BIND == MsFlags::MS_BIND {
+            if is_none_mount_type(mbind.typ()) && flags & MsFlags::MS_BIND == MsFlags::MS_BIND {
                 mbind.set_typ(Some("bind".to_string()));
             }
             mbind
@@ -397,6 +397,13 @@ fn mount_cgroups_v2(cfd_log: RawFd, m: &Mount, rootfs: &str, flags: MsFlags) ->
     Ok(())
 }
 
+fn is_none_mount_type(typ: &Option<String>) -> bool {
+    match typ {
+        Some(t) => t == "none",
+        None => true,
+    }
+}
+
 fn mount_cgroups(
     cfd_log: RawFd,
     m: &Mount,