You can follow below steps from root user to clear the space if it gets stuck at kernel level
lsof +L | grep deleted ## it will show the process id, here it gave process id 21099
cd /proc/<process_id>/fd ## go to process id directory like below
cd /proc/21099/fd
l-wx------ 1 root root 64 Apr 1 2016 30 -> /u00/app/grid/diag/asm/+asm/+ASM1/trace/alert_+ASM1.log_bkup1Aug17 (deleted)
## it will show a link with some number to delete file which is still holding the space
> 30 ##then truncate the file like this, mention the number here with > It will clear the deleted space