Free space from locked files without restarting process

gistfile1.sh

root@hostname:/var/log# df -h | grep lv_var
/dev/rootvg/lv_var    992M  943M     0 100% /var

root@hostname:~# pidof mysqld
17431

root@hostname:~# lsof -p 17431 | grep deleted
mysqld  17431 mysql    1w   REG              252,5          1   32994 /var/log/mysql/error.log.1 (deleted)
mysqld  17431 mysql    2w   REG              252,5          1   32994 /var/log/mysql/error.log.1 (deleted)
mysqld  17431 mysql    4w   REG              252,5          1   32987 /var/log/mysql/mysql-slow.log.1 (deleted)

root@hostname:~# cd /proc/17431/fd

root@hostname:/proc/17431/fd# echo '' > 1
root@hostname:/proc/17431/fd# echo '' > 2
root@hostname:/proc/17431/fd# echo '' > 4

root@hostname:/proc/17431/fd# df -h | grep lv_var
/dev/rootvg/lv_var    992M  200M  742M  22% /var