Hi I am also seeing this same problem. With ATA_DEBUG and AD_DEBUG I see that blocks 127 and 2127 are read successfully and then the panic.
eric haug Saint Louis Univ. > ad0s4: cannot find label (no disk label) > /: bad dir ino 2 at offset 0: mangled entry > panic: ufs_dirbad: bad dir > To Unsubscribe: send mail to majord...@freebsd.org with "unsubscribe freebsd-current" in the body of the message