Oracle Message ORA-01580 - error creating control backup file string

ERRORerror creating control backup file string
CAUSEAn operating system error occurred while attempting to create a control file backup.
ACTIONCheck the error stack for more detailed information

841014Error ORA-01580 in BRSPACE database space administration
725251Known problems in patch level 122 of BR*Tools 6.20
169403Split mirror backup fails with ORA-01580
323332Tablespace extension with ORA-01580 does not work
651351BR tools on UNIX: Error due to executable permissions