Subject: Re: [PATCH RFC 06/24] vfs: break parent dir delegations in open(..., O_CREAT) codepath

From: Al Viro <[email-masked]>
Date: Sun, 17 Mar 2024 00:19:42 +0000

On Fri, Mar 15, 2024 at 12:52:57PM -0400, Jeff Layton wrote:
> In order to add directory delegation support, we need to break
> delegations on the parent whenever there is going to be a change in the
> directory.
> 
> Add a delegated_inode parameter to lookup_open and have it break the
> delegation. Then, open_last_lookups can wait for the delegation break
> and retry the call to lookup_open once it's done.

> @@ -3490,6 +3490,11 @@ static struct dentry *lookup_open(struct nameidata *nd, struct file *file,

Wait a sec - are you going to do anything to the atomic_open side of things?
 
>  	/* Negative dentry, just create the file */
>  	if (!dentry->d_inode && (open_flag & O_CREAT)) {
> +		/* but break the directory lease first! */
> +		error = try_break_deleg(dir_inode, delegated_inode);
> +		if (error)
> +			goto out_dput;