unmounting asm diskgroup do not release the file descriptor

issuing

select * from v$asm_disk in 11gR2 after the unmount/drop disk command. or apply the one off patch in 10g clears the file descriptor.

can be verified lsof /dev/rdisk/disk44 ( or if there is LVM lsof -d /dev/dgsap01 of lsof /dev/dgsap01/rasm* )

metalink Note - 402526.1