Re: Patch "fs: use RCU read side protection in d_validate" broken

[Nick Piggin <npiggin@kernel.dk>]

On Mon, Nov 15, 2010 at 04:11:20PM +1100, Nick Piggin wrote:
> This patch is totally broken. You can't just dget() a dentry with
> nothing but RCU critical section open.
> 
> The patch in my tree this is claimed to be split out of, at least
> attemptet to do some locking, I don't know why that was stripped
> out. But I didn't get that quite right myself at which point I
> decided to just forget about it entirely.
> 
> Christoph, why did you think such a patch is worth getting merged, btw?
> I saw no hint of a justification in your changelog.  I mean, in my tree
> at least there was a _rationale_ that dcache_lock is going away and this
> marginally made the locking simpler. But it doesn't make sense in the
> current tree, even if the merged patch was _not_ buggy -- what were you
> trying to do, make ncpfs's readdir go really fast?

Also, could you try to have a bit more common sense, in general, with
these things?

I mean, your dentry lru modification patch really didn't need to be
pulled ahead of my other patches and and subtly changed. That just
scatters wreckage throughout my patchset, which goes beyond just
merging things up but also all the stress testing and verification I've
done goes out the window too.

Yes, I may not have the thing structured *exactly* as you want it, but
really, unless it is a real problem, just look at the big picture a bit
more.