global lua variables race condition

[dup2]

Using this with lua jit 2.1-20190912 from https://github.com/openresty/luajit2 renders warnings about global variables

[warn] 6#6: *1 [lua] _G write guard:12: __newindex(): writing a global Lua variable ('file_size') which may lead to race conditions between concurrent requests, so prefer the use of 'local' variables

and

[warn] 6#6: *1 [lua] _G write guard:12: __newindex(): writing a global Lua variable ('file_data') which may lead to race conditions between concurrent requests, so prefer the use of 'local' variables