Re: [PATCH 17/19] fs: Reduce inode I_FREEING and factor inode disposal

Nick Piggin
2010-10-17T05:13:17Z

On Sun, Oct 17, 2010 at 03:35:14PM +1100, Nick Piggin wrote:
> On Sun, Oct 17, 2010 at 03:13:13PM +1100, Dave Chinner wrote:
> > On Sun, Oct 17, 2010 at 01:49:23PM +1100, Nick Piggin wrote:
> > > On Sat, Oct 16, 2010 at 09:30:47PM -0400, Christoph Hellwig wrote:
> > > > > * inode->i_lock is *always* the innermost lock.
> > > > > *
> > > > > + * inode->i_lock is *always* the innermost lock.
> > > > > + *
> > > >
> > > > No need to repeat, we got it..
> > >
> > > Except that I didn't see where you fixed all the places where it is
> > > *not* the innermost lock. Like for example places that take dcache_lock
> > > inside i_lock.
> >
> > I can't find any code outside of ceph where the dcache_lock is used
> > within 200 lines of code of the inode->i_lock. The ceph code is not
> > nesting them, though.
>
> You mustn't have looked very hard? From ceph:
>
> spin_unlock(&dcache_lock);
> spin_unlock(&inode->i_lock);
>
> (and yes, acquisition side does go in i_lock->dcache_lock order)

A really quick grep reveals cifs is using GlobalSMBSeslock inside i_lock
too.

Everything uses i_size seqlock inside it, but I guess that's *always*
the inner innermost lock so it doesn't really count.