ORA-15081: failed to submit an I/O operation to a disk
If your are using multi-path make sure that your O.S. does not point to the file system instead of the disk groups. 
  it happened to me 2 times after box reboot.



This is to answer your question:

SQL&gt; set pagesize 800
SQL&gt; select name, label, path from v$asm_disk;
NAME                           LABEL
------------------------------ -------------------------------
PATH

DGER_0000    /dev/oracleasm/disks/DSK5

DGSTBY_0000 /dev/oracleasm/disks/DSKPATHY


 



run the follwing command : 

 /etc/init.d/oracleasm querydisk -d &lt;your disk here&gt;


post the output !