Has there been any previous work or thread about vfs/syscall additions to
allow supporting permissions of non-unix filesystems? The system would
simply permit to obtain or set the particular file permissions from/to a
data block or such... and would allow for instance a unix system to
archive say, NTFS trees preserving permissions...

Of course the extentions would only be allowed to use by uid 0, and would
also permit a userspace environment to run a daemon with superuser
privileges, managing filesystem permissions for a lower user subsystem...
This could for instance be interesting to wine and other win32 API
implementations on unix systems, for Amiga emulators where affs
permissions could be evaluated and changed, etc.

Obviously the kernel would perform no evaluation whatsoever on the
permission data, it merely would only consist of user-settable flags.

Matt