Index: uspace/srv/vfs/vfs_ops.c
===================================================================
--- uspace/srv/vfs/vfs_ops.c	(revision ea44bd16afdbd695c6e1bd7da4d5d2fadfd95753)
+++ uspace/srv/vfs/vfs_ops.c	(revision 6a4e9723578a5975a92f37f68b01835aa5ce1776)
@@ -538,6 +538,6 @@
 
 		phone = vfs_grab_phone(mp_node->fs_handle);
-		rc = async_req_2_0(phone, VFS_OUT_UNMOUNT, mp_node->fs_handle,
-		    mp_node->dev_handle);
+		rc = async_req_2_0(phone, VFS_OUT_UNMOUNT, mp_node->dev_handle,
+		    mp_node->index);
 		vfs_release_phone(phone);
 		if (rc != EOK) {