Comment 122 for bug 93546

> Seems to me that the problem is not the local file system, but network ones
> (nfs, afs, smbfs, cifs, etc), so why not break the problems in two?
>
> firefox detect if the profile file system is a local fs or a network one and
> then:
>
> if local, ...
>
> if network file system, ...

Filesystems are supposed to abstract backing store. If you are trying to "find
out whether filesystem is networked", you are doing something wrong. What next?
"Does my filesystem sit on SATA disk made by Samsung?"

Just act as if your filesystem is always networked (i.e., do not use flock()
locking, use lock files and/or atomic renames).

Apart from this, I like the proposal to make second firefox run in some sort of
"read only" mode.