On Fri, 10 Mar 2000, Erez Zadok wrote:
> Thanks Al.
>
> VFS changes are important to any F/S developer, but even more important to
> me since my stackable templates must behave like both a lower-level F/S and
> a VFS. Ion and I updated our templates to 2.3.49 just a couple of days ago,
> taking into account the previous set of VFS changes.
>
> I was under the impression that this late into 2.3, no such major changes
> were going to happen, so that we get a 2.4 soon, not another long series
> like 2.1. Do you know if there are more (VFS) changes planned in 2.3, and
> if so, which ones? I would prefer to wait until all changes are in, rather
> than spend time on my stacking templates for each change; it would be a
> smaller effort doing it all at once.
Next batches: VOP_FHTOVP() and reverse; better handling ofi module reference
counters (there were oopsable races); getting rid of ->read_inode(); knfsd
cleanup wrt dcache; _badly_ needed cleanup of autofs4; actually working
->getattr() (that will take a while); fixes for races in namei.c (we still
have quite a few barely covered ones);
How much of that will go? Hell knows, ask Linus. Most of those are seriously
needed (read: I can demonstrate bad races). The last thing I want is opening
the hell gates and getting something _really_ icky into the tree (reiserfs,
for one <sounds of violent vomiting>). Devfs was bad enough... So as far as
I'm concerned it's a massive cleanup mode. I _hope_ to get SMP-safe dcache
into 2.4.
> BTW, the new vfs_* things are very nice. They are "stacking friendly." But
> Ion and I noticed other problems that make it hard to do clean stacking.
> For example, there are asymmetries b/t the creation and deletion of inodes
> and dentries; a file system can get notified when a refcnt of an object is
> decreased, but not when it is increased, and more. Ion will send a separate
> detailed mail about that a little later.
Please, do. The things I have in mind for 2.5 are soft-updates and namespaces.
It will require massaging VFS, but currently I just bloody want to clean up
the interactions between dcache and filesystems.
> If you're doing all this VFS work, are you open to suggestions that would
> make stacking cleaner and more flexible? We were going to hold off
> submitting such changes until 2.5, but if 2.3 is going to stretch further,
> we might as well do it now.
No comments on the timescale (I simply don't know - it depends on many things)
but if some stuff will fit well into the current work - why not? Getting the
massive changes is one thing, taking the future stuff into account when
choosing the ways to fix the stuff that needs fixing is another...
BTW, the last couple of batches happened for one reason: they are prerequisites
for fixing knfsd...
