Re: [PATCH v2 1/3] kernfs: allow passing fsnotify event types

[Amir Goldstein]

On Thu, Feb 12, 2026 at 01:58:12PM -0800, T.J. Mercier wrote:
> The kernfs_notify function is hardcoded to only issue FS_MODIFY events
> since that is the only current use case. Allow for supporting other
> events by adding a notify_event field to kernfs_elem_attr. The
> limitation of only one queued event per kernfs_node continues to exist
> as a consequence of the design of the kernfs_notify_list. The new
> notify_event field is protected by the same kernfs_notify_lock as the
> existing notify_next field.
> 
> Signed-off-by: T.J. Mercier <tjmercier@xxxxxxxxxx>

Looks fine
Feel free to add
Acked-by: Amir Goldstein <amir73il@xxxxxxxxx>

> ---
>  fs/kernfs/file.c       | 8 ++++++--
>  include/linux/kernfs.h | 1 +
>  2 files changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c
> index 9adf36e6364b..e978284ff983 100644
> --- a/fs/kernfs/file.c
> +++ b/fs/kernfs/file.c
> @@ -914,6 +914,7 @@ static void kernfs_notify_workfn(struct work_struct *work)
>  	struct kernfs_node *kn;
>  	struct kernfs_super_info *info;
>  	struct kernfs_root *root;
> +	u32 notify_event;
>  repeat:
>  	/* pop one off the notify_list */
>  	spin_lock_irq(&kernfs_notify_lock);
> @@ -924,6 +925,8 @@ static void kernfs_notify_workfn(struct work_struct *work)
>  	}
>  	kernfs_notify_list = kn->attr.notify_next;
>  	kn->attr.notify_next = NULL;
> +	notify_event = kn->attr.notify_event;
> +	kn->attr.notify_event = 0;
>  	spin_unlock_irq(&kernfs_notify_lock);
>  
>  	root = kernfs_root(kn);
> @@ -954,7 +957,7 @@ static void kernfs_notify_workfn(struct work_struct *work)
>  		if (parent) {
>  			p_inode = ilookup(info->sb, kernfs_ino(parent));
>  			if (p_inode) {
> -				fsnotify(FS_MODIFY | FS_EVENT_ON_CHILD,
> +				fsnotify(notify_event | FS_EVENT_ON_CHILD,
>  					 inode, FSNOTIFY_EVENT_INODE,
>  					 p_inode, &name, inode, 0);
>  				iput(p_inode);
> @@ -964,7 +967,7 @@ static void kernfs_notify_workfn(struct work_struct *work)
>  		}
>  
>  		if (!p_inode)
> -			fsnotify_inode(inode, FS_MODIFY);
> +			fsnotify_inode(inode, notify_event);
>  
>  		iput(inode);
>  	}
> @@ -1005,6 +1008,7 @@ void kernfs_notify(struct kernfs_node *kn)
>  	if (!kn->attr.notify_next) {
>  		kernfs_get(kn);
>  		kn->attr.notify_next = kernfs_notify_list;
> +		kn->attr.notify_event = FS_MODIFY;
>  		kernfs_notify_list = kn;
>  		schedule_work(&kernfs_notify_work);
>  	}
> diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
> index b5a5f32fdfd1..1762b32c1a8e 100644
> --- a/include/linux/kernfs.h
> +++ b/include/linux/kernfs.h
> @@ -181,6 +181,7 @@ struct kernfs_elem_attr {
>  	struct kernfs_open_node __rcu	*open;
>  	loff_t			size;
>  	struct kernfs_node	*notify_next;	/* for kernfs_notify() */
> +	u32			notify_event;   /* for kernfs_notify() */
>  };
>  
>  /*
> -- 
> 2.53.0.273.g2a3d683680-goog
>