Re: [PATCH 14/18] fs: Protect inode->i_state with th einode->i_lock

Christoph Hellwig
2010-10-16T16:19:17Z

On Sat, Oct 16, 2010 at 06:57:09PM +1100, Nick Piggin wrote:
> > > Ah, done thinking now! I was so the i_state field had been set
> > > before the inode was added to various lists and potentially
> > > accessable to other threads. I should probably add a comment to that
> > > effect, right?
> >
> > Yes, please.
>
> This is due to i_lock not covering all the icache state of the inode,
> so you have to make these synchronisation changes like this.
>
> I much prefer such proposals to go at the end of my series, where I
> will probably nack them (and use rcu instead if the remaining trylocks
> are such a big issue).

To get back to the context - what it changes is setting up i_state =
I_NEW before adding the inode to the sb-list and the hash. Making
sure objects are fully set up before adding to a list is always a good
idea, and really has nothing to do with RCU.