RFR: 8229872: (fs) Increase buffer size used with getmntent

[Florian Weimer]

* Vladimir Kempik:

> I’m planning to sync setmntent/getmntent on some object via MonitorEnter/Exit to prevent race condition.
> But where to get some jobject ?
> Should I pass it from caller (java method), but then It needs to be some static object.
> Or should I create my own on first usage of setmntent ?

The new race condition is with other processes (not even Java processes)
which do mounts.  There is no way to avoid it reliably.

I still recommend to implement the file parsing in Java.  It's more code
than what's there today only because all of it would currently be
Linux-specific.  Otherwise I expect to be it a simplification.

Thanks,
Florian