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Date: Fri, 14 Jan 2011 03:38:46 +0000
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Nick Piggin <npiggin@gmail.com>
Cc: "J. R. Okajima" <hooanon05@yahoo.co.jp>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
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Subject: Re: vfs-scale, d_revalidate from nfsd
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On Fri, Jan 14, 2011 at 02:29:11PM +1100, Nick Piggin wrote:
> > ? ? ? ?if (nd->flags & LOOKUP_RCU)
> > ? ? ? ? ? ? ? ?return -ECHILD;
> > ? ? ? ?return -EPERM;
> > }
> > when the sole intent of that sucker is to have dentry of /.xattr (pinned
> > in dcache and hashed all along) rejected on lookups from root? ?IOW, WTF
> > bother with -ECHILD here at all?
> 
> That's true. I guess I always have a weakness for doing "just one
> little easy optimisation/simplification" folded into patch that is supposed
> to be more mechanical changes :) I did have exactly that in the patch
> initially, but I decided it's better just to do everything with -ECHILD first.
> 
> That also gives the -ECHILD paths a bit more workout before
> fs conversions are done, too.

Not unless your test loads include trying to access pathnames like
/.xattr/whatever on reiserfs and watching those attempts fail...