Re: silent semantic changes with reiser4

From: Hans Reiser
Date: Sun Aug 29 2004 - 21:24:47 EST


You are assuming that the hiding has to be embodied by the dentry cache. That sounds hard. Let's not do that; I am too lazy.

We can put it at a layer above that. Let us have a "mask" concept. For the purposes of this discussion, the mask can be made totally trivial and hardcoded, with none of the expressive power of my new DoD project, and can probably be coded in a few hours to exclude the metas. For my new DoD project we are creating a configurable, scalable, sophisticated "mask" abstraction, and you must successfully pass through the mask before you can ask if the filesystem contains X/Y/Z. (For the darpa project with the general purpose masks with specifications and all that we will take 6 months, not a few hours.)

The rest shall wait until after I get a bite to eat, ok?

Hans

viro@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx wrote:

On Sun, Aug 29, 2004 at 01:06:41PM -0700, Hans Reiser wrote:



How about if you educate me on the problems you see for a bit before I respond? I think it might help us move into a constructive discussion.



A slew of cache coherency issues (and memory consumption on top of that).
Rigth now we have a signle dentry tree for all fs instances, no matter
how many times it and its subtrees are visible in the tree. Which,
obviously, avoids all that crap. As soon as we start trying to have
multiple trees over the same fs, we are in for a *lot* of fun.




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