Linux ACL designe - why the POSIX draft?

[Nicholas Miell]

With all the recent discussion about ACLs and Linux on
linux-kernel, I was wondering why the ACL implementations
for Linux are based off the withdrawn POSIX 1003.1e draft
17?

Is there any particular reason why this was chosen for
the basis for the Linux ACL system, besides the fact
that its what everybody else did? (It is a only a
withdrawn draft after all, there's no reason to actually
follow it...)

Wouldn't a more flexible solution, perhaps one based on 
the NFSv4 ACL design[1] be better?

Because the NFSv4 design is in effect a superset of the
POSIX 1003.1e draft functionality, all Unix filesystems
with ACLs could be easily supported by the Linux VFS, and
the task of implementing NFSv4, NTFS, and SMB would be
made easier[2] because of it.

Thanks, Nicholas

[1] Actually, it was the Windows NT/2000/XP design first...

[2] The VFS would still need some means of mapping the SIDs
used by SMB and NTFS and the UTF-8 strings used by NFSv4 to
usable uid_t's and gid_t's, but at least the ACLs would be
easy.