From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Morton <akpm@osdl.org>
Subject: Re: [PATCH 7/5] Optimise d_find_alias()
Date: Fri, 3 Mar 2006 03:45:52 -0800
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To: David Howells <dhowells@redhat.com>
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David Howells <dhowells@redhat.com> wrote:
>
>  struct dentry * d_find_alias(struct inode *inode)
>   {
>  -	struct dentry *de;
>  -	spin_lock(&dcache_lock);
>  -	de = __d_find_alias(inode, 0);
>  -	spin_unlock(&dcache_lock);
>  +	struct dentry *de = NULL;
>  +	if (!list_empty(&inode->i_dentry)) {
>  +		spin_lock(&dcache_lock);
>  +		de = __d_find_alias(inode, 0);
>  +		spin_unlock(&dcache_lock);
>  +	}
>   	return de;
>   }

How can we get away without a barrier?