Messages in this thread | | | Date | Thu, 27 Jul 2000 15:38:27 -0400 | From | "Theodore Y. Ts'o" <> | Subject | Re: NFSv4 ACLs (was: ...ACL's and reiser...) |
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"Albert D. Cahalan" <acahalan@cs.uml.edu>: > Michael Gerdts writes: > > > When implementing ACL's please read over section 5.9 of the NFSv4 draft. > > http://www.ietf.org/internet-drafts/draft-ietf-nfsv4-07.txt > > > > By designing ACL's (and other things) to work well with NFSv4 from the > > start, reiserfs will likely have a leg up on the competition inside and > > outside of the Linux arena for being able to support NFSv4. > > Wow, that is almost pure NT 4.0, with 4 of 7 authors being from Sun! > The only difference is that the 17 access mask bits are all specific; > there is no concept of mapping generic bits to object-specific bits. > The inheritance, types, and scanning algorithm are all from NT.
No, it's not pure NT, for which we can be very thankful. In particular, it's not the case that you have to scan up the entire directory hierarchy looking to see which ACL's might apply to a particular file. Access control entries only apply apply to the current directory or file, and while certain ACE's can be marked as be "inheritable" in a directory, it only applies to newly created files, not all files underneath that directory.
(In NT, if "bob" is given access to /usr, the he has access to /usr/lib, /usr/local, /usr/bin, /usr/etc, /usr/home/tytso/Mail, etc. You have to scan all of the ACL's up to the root whenever you make an access decision. This is slow and painful, and doesn't have much semantic meaning in the presence of hard links --- which NT doesn't have.)
- Ted
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