Re: PROBLEM: FUSE_NOTIFY_INVAL_ENTRY leaves stale negative dentry after c9ba789dad15

[Miklos Szeredi]

On Tue, 2 Jun 2026 at 01:43, NeilBrown <neilb@xxxxxxxxxxx> wrote:

> diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
> index b658b6baf72f..3f16ecbc358e 100644
> --- a/fs/fuse/dir.c
> +++ b/fs/fuse/dir.c
> @@ -1605,13 +1605,29 @@ int fuse_reverse_inval_entry(struct fuse_conn *fc, u64 parent_nodeid,
>                 struct dentry *child = try_lookup_noperm(name, dir);
>                 if (!child || IS_ERR(child))
>                         goto put_parent;
> -               entry = start_removing_dentry(dir, child);
> -               dput(child);
> -               if (IS_ERR(entry))
> -                       goto put_parent;
> -               if (!d_same_name(entry, dir, name)) {
> -                       end_removing(entry);
> -                       entry = NULL;
> +               if (d_really_is_negative(child)) {
> +                       spin_lock(&child->d_lock);
> +                       if (d_really_is_negative(child)) {
> +                               fuse_dir_changed(parent);
> +                               if (!(flags & FUSE_EXPIRE_ONLY))
> +                                       __d_drop(entry);
> +                               fuse_invalidate_entry_cache(entry);

s/entry/child/ for the above two lines

Otherwise looks good and tests OK.

Agree about the need for comments.

Thanks,
Miklos