daemon: Fix type signature of mount_vfs (RHBZ#1564983).

Reported-by: Yongkui Guo.

Fixes commit 82bbd9c8a5.

daemon/inspect_fs.ml

@@ -39,14 +39,12 @@ let rec check_for_filesystem_on mountable vfs_type =
         if vfs_type = "ufs" then ( (* Hack for the *BSDs. *)
           (* FreeBSD fs is a variant of ufs called ufs2 ... *)
           try
-            Mount.mount_vfs (Some "ro,ufstype=ufs2") (Some "ufs")
-                            mountable "/";
+            Mount.mount_vfs "ro,ufstype=ufs2" "ufs" mountable "/";
             true
           with _ ->
             (* while NetBSD and OpenBSD use another variant labeled 44bsd *)
             try
-              Mount.mount_vfs (Some "ro,ufstype=44bsd") (Some "ufs")
-                              mountable "/";
+              Mount.mount_vfs "ro,ufstype=44bsd" "ufs" mountable "/";
               true
             with _ -> false
         ) else (

daemon/mount.ml

@@ -32,22 +32,22 @@ let mount_vfs options vfs mountable mountpoint =
 
   (* -o options *)
   (match options, mountable.m_type with
-   | (None | Some ""), (MountableDevice | MountablePath) -> ()
-   | Some options, (MountableDevice | MountablePath) ->
+   | "", (MountableDevice | MountablePath) -> ()
+   | options, (MountableDevice | MountablePath) ->
       List.push_back args "-o";
       List.push_back args options
-   | (None | Some ""), MountableBtrfsVol subvol ->
+   | "", MountableBtrfsVol subvol ->
       List.push_back args "-o";
       List.push_back args ("subvol=" ^ subvol)
-   | Some options, MountableBtrfsVol subvol ->
+   | options, MountableBtrfsVol subvol ->
       List.push_back args "-o";
       List.push_back args ("subvol=" ^ subvol ^ "," ^ options)
   );
 
   (* -t vfs *)
   (match vfs with
-   | None | Some "" -> ()
-   | Some t ->
+   | "" -> ()
+   | t ->
       List.push_back args "-t";
       List.push_back args t
   );
@@ -57,9 +57,9 @@ let mount_vfs options vfs mountable mountpoint =
 
   ignore (command "mount" !args)
 
-let mount = mount_vfs None None
-let mount_ro = mount_vfs (Some "ro") None
-let mount_options options = mount_vfs (Some options) None
+let mount = mount_vfs "" ""
+let mount_ro = mount_vfs "ro" ""
+let mount_options options = mount_vfs options ""
 
 (* Unmount everything mounted under /sysroot.
  *

daemon/mount.mli

@@ -19,6 +19,6 @@
 val mount : Mountable.t -> string -> unit
 val mount_ro : Mountable.t -> string -> unit
 val mount_options : string -> Mountable.t -> string -> unit
-val mount_vfs : string option -> string option -> Mountable.t -> string -> unit
+val mount_vfs : string -> string -> Mountable.t -> string -> unit
 
 val umount_all : unit -> unit