to go to the FS image we are making cannot be read (e.g. EPERM). Current behaviour when we issue waring but still proceeed and return success is definitely not correct: masking out error condition as well as making a slighly inconsistent FS where attempt to access the file in question ends up in EBADF. See linked DR for details. MFC after: 1 month Differential Revision: https://reviews.freebsd.org/D18584