PROPOSAL: extend UNIX_INFO2 to mark existence of ACLs

[Shirish Pargaonkar]

On Jan 22, 2008 3:32 PM, James Peach <jpeach at apple.com> wrote:
>
> On Jan 22, 2008, at 1:23 PM, Steve French wrote:
>
> > James Peach wrote:
> >
> >> Hi all,
> >>
> >> Unix SMB client could often avoid a few round-trips to the server
> >> if  they could tell whether a file had an ACL at the point where
> >> they  query its metadata (presumably using the UNIX_INFO2 info
> >> level).
> >>
> >> Since the permissions field is 64bits, how about stealing the high
> >> bit  of this field to indicate whether the file might have an ACL?
> >>
> >> We'd probably need a mechanism for clients to figure out whether
> >> the  bit was meaningful or not ....
> >>
> >>
> > Do you mean POSIX ACL or NT ACL?
> > For the case of an NT ACL, how would you distinguish between the
> > case in which the file has an emulated ACL and a "real" ACL?  If you
> > query the NT ACL eg. with smbcacls, Samba will report one, even on
> > files which do not have an ACL.
> >
>
> You might be able to tell that I haven't thought this through very
> thoroughly yet :)
>
> But I think that I agree with Simo that the server should only set the
> bit for a "real" ACL, ie. it should not set the bit for files whose
> only ACL is fabricated from the POSIX permissions bits.
>

Could someone please explain what are   few round-trips   to the server
and what is an emulated ACL?