linux fio write the disk , how to recover .very urgent. help me,please, : I`m use os is  CentOS release 6.6 . today , i want to test the disk write speed. 
i have a 500g disk is /dev/sdc.
i use the cmd  :
fio -filename=/dev/sdc -direct=1 -iodepth 1 -thread -rw=randwrite  -ioengine=psync -bs=16k -size=1G -numjobs=5 -runtime=15 -group_reporting -name=mytest
when i use the cmd df -h look the disk: 
Filesystem            Size  Used Avail Use% Mounted on
 9.0Z  9.0Z     0 100% /data
and in /data ,i use ls ,but i can`t see any data
disk is ext4 !
how can i recover it !!! i`m very worry 。please help me !! thanks very much !!