diff --git a/mllib/common_utils.ml b/mllib/common_utils.ml
index 966069209..69118da41 100644
--- a/mllib/common_utils.ml
+++ b/mllib/common_utils.ml
@@ -942,3 +942,10 @@ let inspect_mount_root g ?mount_opts_fn root =
 
 let inspect_mount_root_ro =
   inspect_mount_root ~mount_opts_fn:(fun _ -> "ro")
+
+let is_btrfs_subvolume g fs =
+  try
+    ignore (g#mountable_subvolume fs); true
+  with Guestfs.Error msg as exn ->
+    if g#last_errno () = Guestfs.Errno.errno_EINVAL then false
+    else raise exn
diff --git a/mllib/common_utils.mli b/mllib/common_utils.mli
index 44b3018a2..9b1086cc8 100644
--- a/mllib/common_utils.mli
+++ b/mllib/common_utils.mli
@@ -368,3 +368,6 @@ val inspect_mount_root : Guestfs.guestfs -> ?mount_opts_fn:(string -> string) ->
 val inspect_mount_root_ro : Guestfs.guestfs -> string -> unit
 (** Like [inspect_mount_root], but mounting every mount point as
     read-only. *)
+
+val is_btrfs_subvolume : Guestfs.guestfs -> string -> bool
+(** Checks if a filesystem is a btrfs subvolume. *)