On Wed, Jun 09, 2021 at 04:50:27PM +0800, Ian Kent wrote:
> + if (d_really_is_negative(dentry)) {
> + struct dentry *d_parent = dget_parent(dentry);
> + struct kernfs_node *parent;
What the hell is dget_parent() for? You don't do anything blocking
here, so why not simply grab dentry->d_lock - that'll stabilize
the value of ->d_parent just fine. Just don't forget to drop the
lock before returning and that's it...
> + /* If the kernfs parent node has changed discard and
> + * proceed to ->lookup.
> + */
> + parent = kernfs_dentry_node(d_parent);
> + if (parent) {
> + if (kernfs_dir_changed(parent, dentry)) {
> + dput(d_parent);
> + return 0;
> + }
> + }
> + dput(d_parent);
> +
> + /* The kernfs node doesn't exist, leave the dentry
> + * negative and return success.
> + */
> + return 1;
> + }
