Re: [git pull] vfs pile, part 2

From: Al Viro
Date: Fri May 28 2010 - 15:48:01 EST


On Fri, May 28, 2010 at 12:27:51PM -0700, Sage Weil wrote:
> Hi Al,
>
> There are two patches
>
> 1f24668c vfs: make real_lookup do dentry revalidation with i_mutex held
> 982ddae4 vfs: clean up do_lookup()
>
> that were in your for-next a few weeks back but aren't anymore (they're
> still in your autofs branch). I just want to make sure those don't get
> lost if they're not going to make it upstream this time around? I think
> they've been in vfs-2.6.git limbo for two release cycles now.

My apologies, I thought you'd been Cc'd on the discussions with Ian concerning
that stuff, but...

The bottom line: "autofs4: always use lookup for lookup" is needed for them
and it had to be reverted since it'd been FUBAR.

Details: we really, *really* can not do things in ->d_revalidate() and count
on ->lookup() to come and finish them. Think for a minute and you'll see why -
between these two calls we allocate a dentry to pass to ->lookup(). What
happens if that allocation fails?

And without that patch your stuff breaks autofs4. So it's waiting for the
->d_revalidate() interface redesign. Hopefully in the coming cycle...
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