Display an error if home path is not valid for a subvolume

src/include/users/dialogs.rb

@@ -1370,6 +1370,7 @@ def EditUserDialog(what)
             no_skel = Convert.to_boolean(UI.QueryWidget(Id(:skel), :Value))
             mode = Convert.to_string(UI.QueryWidget(Id(:mode), :Value))
           end
+
           if Ops.add(Builtins.findlastof(new_home, "/"), 1) ==
               Builtins.size(new_home)
             new_home = Builtins.substring(
@@ -1533,6 +1534,22 @@ def EditUserDialog(what)
             create_home = false
           end
 
+          # A flag to decide if the Btrfs path validation should be performed, since it is not
+          # needed when moving it to other location. The "create_home" above is not reliable because
+          # it is "true" **when moving the directory/subvolume**.
+          check_btrfs_path = !UI.QueryWidget(Id(:move_home), :Value)
+
+          # Check if is a valid path when creating a Btfs subvolume
+          if btrfs_subvolume && check_btrfs_path && !valid_btrfs_path?(new_home)
+            Report.Error(
+              _("Given path is not a valid Btrfs location.\n\n" \
+              "Choose another path for the home directory\n" \
+              "or uncheck the 'Btrfs subvolume' option.")
+            )
+            focus_tab.call(current, :home)
+            next
+          end
+
           home = new_home
           shell = new_shell
           uid = new_i_uid