Re: [PATCH 12/17] rpc_mkpipe_dentry(): switch to start_creating()

[Jeff Layton <jlayton@kernel.org>]

On Fri, 2025-06-13 at 08:34 +0100, Al Viro wrote:
> ... and make sure we set the rpc_pipe-private part of inode up before
> attaching it to dentry.
> 

"rpc_pipe->private"

nit: subject should say  "...switch to simple_start_creating()".

> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
> ---
>  net/sunrpc/rpc_pipe.c | 83 +++++++++++++++----------------------------
>  1 file changed, 29 insertions(+), 54 deletions(-)
> 
> diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
> index 8f88c75c9b30..a52fe3bbf9dc 100644
> --- a/net/sunrpc/rpc_pipe.c
> +++ b/net/sunrpc/rpc_pipe.c
> @@ -485,31 +485,6 @@ rpc_get_inode(struct super_block *sb, umode_t mode)
>  	return inode;
>  }
>  
> -static int __rpc_create_common(struct inode *dir, struct dentry *dentry,
> -			       umode_t mode,
> -			       const struct file_operations *i_fop,
> -			       void *private)
> -{
> -	struct inode *inode;
> -
> -	d_drop(dentry);
> -	inode = rpc_get_inode(dir->i_sb, mode);
> -	if (!inode)
> -		goto out_err;
> -	inode->i_ino = iunique(dir->i_sb, 100);
> -	if (i_fop)
> -		inode->i_fop = i_fop;
> -	if (private)
> -		rpc_inode_setowner(inode, private);
> -	d_add(dentry, inode);
> -	return 0;
> -out_err:
> -	printk(KERN_WARNING "%s: %s failed to allocate inode for dentry %pd\n",
> -			__FILE__, __func__, dentry);
> -	dput(dentry);
> -	return -ENOMEM;
> -}
> -
>  static void
>  init_pipe(struct rpc_pipe *pipe)
>  {
> @@ -546,25 +521,6 @@ struct rpc_pipe *rpc_mkpipe_data(const struct rpc_pipe_ops *ops, int flags)
>  }
>  EXPORT_SYMBOL_GPL(rpc_mkpipe_data);
>  
> -static int __rpc_mkpipe_dentry(struct inode *dir, struct dentry *dentry,
> -			       umode_t mode,
> -			       const struct file_operations *i_fop,
> -			       void *private,
> -			       struct rpc_pipe *pipe)
> -{
> -	struct rpc_inode *rpci;
> -	int err;
> -
> -	err = __rpc_create_common(dir, dentry, S_IFIFO | mode, i_fop, private);
> -	if (err)
> -		return err;
> -	rpci = RPC_I(d_inode(dentry));
> -	rpci->private = private;
> -	rpci->pipe = pipe;
> -	fsnotify_create(dir, dentry);
> -	return 0;
> -}
> -
>  static int rpc_new_file(struct dentry *parent,
>  			   const char *name,
>  			   umode_t mode,
> @@ -704,8 +660,10 @@ static struct dentry *rpc_mkdir_populate(struct dentry *parent,
>  int rpc_mkpipe_dentry(struct dentry *parent, const char *name,
>  				 void *private, struct rpc_pipe *pipe)
>  {
> -	struct dentry *dentry;
>  	struct inode *dir = d_inode(parent);
> +	struct dentry *dentry;
> +	struct inode *inode;
> +	struct rpc_inode *rpci;
>  	umode_t umode = S_IFIFO | 0600;
>  	int err;
>  
> @@ -715,16 +673,33 @@ int rpc_mkpipe_dentry(struct dentry *parent, const char *name,
>  		umode &= ~0222;
>  
>  	dentry = simple_start_creating(parent, name);
> -	if (IS_ERR(dentry))
> -		return PTR_ERR(dentry);
> -	err = __rpc_mkpipe_dentry(dir, dentry, umode, &rpc_pipe_fops,
> -				  private, pipe);
> -	if (unlikely(err))
> -		pr_warn("%s() failed to create pipe %pd/%s (errno = %d)\n",
> -			__func__, parent, name, err);
> -	else
> -		pipe->dentry = dentry;
> +	if (IS_ERR(dentry)) {
> +		err = PTR_ERR(dentry);
> +		goto failed;
> +	}
> +
> +	inode = rpc_get_inode(dir->i_sb, umode);
> +	if (unlikely(!inode)) {
> +		dput(dentry);
> +		inode_unlock(dir);
> +		err = -ENOMEM;
> +		goto failed;
> +	}
> +	inode->i_ino = iunique(dir->i_sb, 100);
> +	inode->i_fop = &rpc_pipe_fops;
> +	rpci = RPC_I(inode);
> +	rpci->private = private;
> +	rpci->pipe = pipe;
> +	rpc_inode_setowner(inode, private);
> +	d_instantiate(dentry, inode);
> +	pipe->dentry = dentry;
> +	fsnotify_create(dir, dentry);
>  	inode_unlock(dir);
> +	return 0;
> +
> +failed:
> +	pr_warn("%s() failed to create pipe %pd/%s (errno = %d)\n",
> +			__func__, parent, name, err);
>  	return err;
>  }
>  EXPORT_SYMBOL_GPL(rpc_mkpipe_dentry);

-- 
Jeff Layton <jlayton@kernel.org>