Re: (reiserfs) Re: NFSv4 ACLs (was: ...ACL's and reiser...)

[=?iso-8859-1?Q?Ragnar_Kj=F8rstad?=]

On Sun, Aug 06, 2000 at 11:56:34PM +0200, Xuan Baldauf wrote:
> > > P.P.S.: To the question: "What are you storing in the cache?": I store the list of
> > > pending acl-change orders in the cache. (The word cache was quite misleading.
> > > Sorry.)
> >
> > What if the data changes before your background thread have finished
> > updating the ACLs?
> >
> > 1. change ACLs for /dir recursively
> > 2. chage ACL for /dir/file
> > 3. thread executing (1) changes ACL of /dir/file
> 
> I knew that this question would come. So order the list of requested changes (the most
> recent one at top, the oldest one at bottom). The background thread popps the orders
> from the bottom, always hurrying to be in current state. The check (if the list is not
> empty) has to work like going from top to bottom. (I say "has to work like", because you
> can think if implementations where checking is implemented with a tree. If a match in
> this tree is found, there should be tests wether the the inner entry (/dir/file) or the
> outer entry (/dir) is newer.

What if:
1. change ACLs for /dir recursively
2. touch /dir/file
3. thread executing (1) changes ACL of /dir/file

BTW: This approach means ACL must be in directory-entry, because there
is no way to check if the cache contains ACLdata for a specific "inode",
just path.

-- 
Ragnar Kjorstad
Torque Systems / Big Storage