Messages in this thread |  | | | Date | Fri, 28 Jul 2000 10:49:25 -0400 | | From | "Theodore Y. Ts'o" <> | | Subject | Re: (reiserfs) Re: NFSv4 ACLs (was: ...ACL's and reiser...) |
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Date: Fri, 28 Jul 2000 16:39:23 +0200 From: Xuan Baldauf <xuan--reiserfs@baldauf.org>
> and I open the file "stupid", I don't have to either traverse all of the > directories down to the pathname, and I don't have to do any permissions > checks in all of the parent directories of the cwd. For inheriting ACLs, you do not have to traverse all the path components either, because you can use your cached resolved ACLs for your cwd ".../really", can't you?
In order handle stuff like ../../bill/gates/sucks, you have to cache the ACL's at a per-directory level, and not fully resolved. (Or you could do both, but now you're talking memory bloat issues). And of course, if you do all of this cacheing, the moemnt you want to change an ACL, you have to go all over the place invalidiating caches.
This becomes particularly disastrous over networked filesystems, since you have to send all of these invalidates over the network. Fortunately, as I said, NFSv4 eschews dynamic inheritance. (They specifically state that inheritance only applies to newly created files, and not to existing files. At this point, it's basically the standards Multics's per-directory default creation ACL, which is assigned to all new files created in that directory.)
- Ted
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