Re: [NFS][PATCH] Making sure negative lookup entries don't exist

[Mike Waychison <Michael.Waychison@Sun.COM>]

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Steve Dickson wrote:
> Here is a 2.4.28 patch that ensures negative cached dirents
> do not exist by always doing an otw getattr to the server.
> This does cause a small increase in getattrs (~3% from what
> I saw in my testing) but it seems to me the price is worth it to
> ensure the client does not lie about the existence of a file.
> 
> comments?
> 
> steved.
> 
> 
> ------------------------------------------------------------------------
> 
> --- linux-2.4.28/fs/nfs/dir.c.orig	2004-08-07 19:26:06.000000000 -0400
> +++ linux-2.4.28/fs/nfs/dir.c	2005-01-28 13:00:59.402239000 -0500
> @@ -455,7 +455,11 @@ int nfs_lookup_verify_inode(struct inode
>   */
>  static inline int nfs_neg_need_reval(struct inode *dir, struct dentry *dentry)
>  {
> -	if (!nfs_check_verifier(dir, dentry))
> +	if (IS_ROOT(dentry))
> +		return 1;

I don't think this is needed.  Aren't you guaranteed that a root dentry
will never have ->d_revalidate called?

> +	if (__nfs_revalidate_inode(NFS_SERVER(dir), dir))
> +		return 1;
> +	if (time_after(NFS_MTIME_UPDATE(dir), dentry->d_time))
>  		return 1;
>  	return time_after(jiffies, dentry->d_time + NFS_ATTRTIMEO(dir));
>  }

Am I missing something? or doesn't nfs_check_verifier do exactly these
checks already?

- --
Mike Waychison
Sun Microsystems, Inc.
1 (650) 352-5299 voice
1 (416) 202-8336 voice

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