Re: reiser4: maybe just fix bugs?

From: Andrew Morton
Date: Tue Aug 01 2006 - 10:52:13 EST

On Tue, 01 Aug 2006 21:52:03 +1000
Nick Piggin <nickpiggin@xxxxxxxxxxxx> wrote:

> Andrew Morton wrote:
> > On Mon, 31 Jul 2006 10:26:55 +0100
> > "Denis Vlasenko" <vda.linux@xxxxxxxxxxxxxx> wrote:
> >
> >
> >>The reiser4 thread seem to be longer than usual.
> >
> >
> > Meanwhile here's poor old me trying to find another four hours to finish
> > reviewing the thing.
> >
> > The writeout code is ugly, although that's largely due to a mismatch between
> > what reiser4 wants to do and what the VFS/MM expects it to do. If it
> > works, we can live with it, although perhaps the VFS could be made smarter.
> >
> > I'd say that resier4's major problem is the lack of xattrs, acls and
> > direct-io. That's likely to significantly limit its vendor uptake. (As
> > might the copyright assignment thing, but is that a concern?)
> >
> > The plugins appear to be wildly misnamed - they're just an internal
> > abstraction layer which permits later feature additions to be added in a
> > clean and safe manner. Certainly not worth all this fuss.
> >
> > Could I suggest that further technical critiques of reiser4 include a
> > file-and-line reference? That should ease the load on vger.
> I haven't really reviewed it, but when I grepped through it last, I
> found a few alarming things, like use of __put_page, trying to remove
> pages from pagecache (duplicating parts of vmscan.c, plus bugs), and
> taking tree_lock.

__put_page() has gone.

A lot of the VM duplication has gone.

tree_lock is still there a bit. For two reasons:

a) A presently-unneeded duplication of the generic
__set_page_dirty_nobuffers() and

b) Manipulation of the fake inode (I think).

iirc the base problem here is that for whatever reason, the usual
blockdev inode which filesystems use for metadata (ie: the pagecache
which backs sb_bread(), etc) isn't suitable. reiser4 wants to get a
hold of its address_space ops, so it needs to create its own
covers-all-the-partition, identify-mapped address_space.

> Mostly didn't look like big problems to fix, but should be fixed for
> mm/ maintainers' sanity. Maybe it's better now, though.

It's better. More reviewing help is always appreciated ;)
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