fsstress: check system call return values

Check the return values of various system calls and blow up if something
went wrong.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-By: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
1 file changed