oracleasm createdisk marking disk FAILED with Unable to open device Device or resource busy

While adding new lun on the ASM storage we are getting below error in /var/log/oracleasm

Error:
/etc/init.d/oracleasm createdisk ASM_DISK02 /dev/sdf1
Marking disk "ASM_DATA02" as an ASM disk: [FAILED]

and in /var/log/oracleasm we are getting below error

Unable to open device "/dev/sdf1": Device or resource busy
Unable to open device "/dev/sdf1": Device or resource busy


Solution:

We are using multipath storage for backup.So in /etc/multipath.conf ,we blacklist the wwid of the new luns.

Then we are able to createdisk at asm level.