oracleasm createdisk fails with no additional error message

ASM

Problem Description
“oracleasm configure” works fine but whenever it is tried to create disk for ASM using createdisk command it fails like below.

# /etc/init.d/oracleasm createdisk VOL1 /dev/sdc1
Creating Oracle ASM disk "VOL1" [FAILED]

Running createdisk with strace show the device /dev/sdc1 is busy

# strace -f /etc/init.d/oracleasm createdisk VOL1 /dev/sdc1
...
19543 open("/dev/sdc1", O_RDWR|O_EXCL) = -1 EBUSY (Device or resource busy)
...
19543 write(2, "Unable to open device "/dev/sdc1"..., 59 >unfinished ...<
...
19527 write(1, "FAILED", 6) = 6

Cause of the Problem
The device in question (/dev/sdc1) is already mounted on a directory.

# mount | grep sdc1
/dev/sdc1 on /mnt type ext3 (rw)

Solution of the Problem
1. Unmount the device /dev/sdc1 and make sure it is not mounted anymore.

# umount /dev/sdc1
# mount | grep sdc1

2. Retry createdisk:

# /etc/init.d/oracleasm createdisk VOL1 /dev/sdc1
Creating Oracle ASM disk "VOL1" [ OK ]