Hi. I'm sorry to disturb other guys.
in my former company, RHEL 5.4 is the main OS. we had to follow the rule.
so I want to solve this problem.
There are 2 answers.
easy one is just use fsync instead of sync_file_range but it is slower than
another is using sync_file_range as well as possible.
I already sent a patch about this. but I'm not sure that it is a good way.
if someone tried custom environment, It may fail.
but. I still think RHEL5 is very important OS. especially in Korea, most
company may use this version.