[RFC, PATCH, RESEND] fs: push rcu_barrier() from deactivate_locked_super() to filesystems

[Andrew Morton]

On Fri, 8 Jun 2012 23:27:34 +0100
Al Viro <viro at ZenIV.linux.org.uk> wrote:

> On Fri, Jun 08, 2012 at 03:25:50PM -0700, Andrew Morton wrote:
> 
> > A neater implementation might be to add a kmem_cache* argument to
> > unregister_filesystem().  If that is non-NULL, unregister_filesystem()
> > does the rcu_barrier() and destroys the cache.  That way we get to
> > delete (rather than add) a bunch of code from all filesystems and new
> > and out-of-tree filesystems cannot forget to perform the rcu_barrier().
> 
> There's often enough more than one cache, so that one is no-go.

kmem_cache** ;)

Which filesystems have multiple inode caches?