On Sat, 2021-06-12 at 00:07 +0000, Al Viro wrote:
> 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...
Thanks Al, I'll change 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;
> > + }
