Re: [PATCH 3/5] nfsctl: Use vfs_path_lookup

[Christoph Hellwig <hch@infradead.org>]

On Sun, May 06, 2007 at 01:41:27PM -0400, Josef 'Jeff' Sipek wrote:
> use vfs_path_lookup instead of open-coding the necessary functionality.
> 
> Signed-off-by: Josef 'Jeff' Sipek <jsipek@cs.sunysb.edu>
> ---
>  fs/nfsctl.c |   15 +++++----------
>  1 files changed, 5 insertions(+), 10 deletions(-)
> 
> diff --git a/fs/nfsctl.c b/fs/nfsctl.c
> index c043136..c97df14 100644
> --- a/fs/nfsctl.c
> +++ b/fs/nfsctl.c
> @@ -23,19 +23,14 @@
>  static struct file *do_open(char *name, int flags)
>  {
>  	struct nameidata nd;
> +	struct vfsmount *mnt;
>  	int error;
>  
> -	nd.mnt = do_kern_mount("nfsd", 0, "nfsd", NULL);
> +	mnt = do_kern_mount("nfsd", 0, "nfsd", NULL);
> +	if (IS_ERR(mnt))
> +		return (struct file *)mnt;
>  
> -	if (IS_ERR(nd.mnt))
> -		return (struct file *)nd.mnt;
> -
> -	nd.dentry = dget(nd.mnt->mnt_root);
> -	nd.last_type = LAST_ROOT;
> -	nd.flags = 0;
> -	nd.depth = 0;
> -
> -	error = path_walk(name, &nd);
> +	error = vfs_path_lookup(mnt->mnt_root, mnt, name, 0, &nd);
>  	if (error)
>  		return ERR_PTR(error);

I think you're leaking a reference on the mount here as we didn't
do a mntget before.  We need to do an additional mntput just after
the lookup to drop the reference from do_kern_mount.