Re: [PATCH 0/7] Permit filesystem local caching and NFS superblocksharing [try #13]

[Trond Myklebust]

On Tue, 2006-09-05 at 12:06 +0800, Ian Kent wrote:

> > One way to fix this is to simply not hash the dentry when we're doing
> > the O_EXCL intent optimisation, but rather to only hash it _after_ we've
> > successfully created the file on the server. Something like the attached
> > patch ought to do it.
> 
> No.
> 
> This patch simply marks the dentry negative and returns ENOMEM from the
> lookup which, as would be expected, results in this error being returned
> to userspace.

Oops. You are right. I forgot to set res=NULL...


> --- Begin Message ---
> Signed-off-by: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
> ---
>
>  fs/nfs/dir.c |   14 +++++++++++---
>  1 files changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
> index 51328ae..3419c2d 100644
> --- a/fs/nfs/dir.c
> +++ b/fs/nfs/dir.c
> @@ -904,9 +904,15 @@ static struct dentry *nfs_lookup(struct 
>  
>  	lock_kernel();
>  
> -	/* If we're doing an exclusive create, optimize away the lookup */
> -	if (nfs_is_exclusive_create(dir, nd))
> -		goto no_entry;
> +	/*
> +	 * If we're doing an exclusive create, optimize away the lookup
> +	 * but don't hash the dentry.
> +	 */
> +	if (nfs_is_exclusive_create(dir, nd)) {
> +		d_instantiate(dentry, NULL);
> +		res = NULL;
> +		goto out_unlock;
> +	}
>  
>  	error = NFS_PROTO(dir)->lookup(dir, &dentry->d_name, &fhandle, &fattr);
>  	if (error == -ENOENT)
> @@ -1161,6 +1167,8 @@ int nfs_instantiate(struct dentry *dentr
>  	if (IS_ERR(inode))
>  		return error;
>  	d_instantiate(dentry, inode);
> +	if (d_unhashed(dentry))
> +		d_rehash(dentry);
>  	return 0;
>  }
>  
>
> --- End Message ---