Re: [PATCH v5 09/21] nfsd: add data structures for handling CB_NOTIFY

[Chuck Lever]

On Fri, May 22, 2026, at 3:42 PM, Jeff Layton wrote:
> Add the data structures, allocation helpers, and callback operations
> needed for directory delegation CB_NOTIFY support:

> diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
> index 9c6e2e7abc82..505fabf8f1bf 100644
> --- a/fs/nfsd/state.h
> +++ b/fs/nfsd/state.h
> @@ -197,6 +197,44 @@ struct nfs4_cb_fattr {
>  #define NOTIFY4_EVENT_QUEUE_SIZE	3
>  #define NOTIFY4_PAGE_ARRAY_SIZE		1
> 
> +struct nfsd_notify_event {
> +	refcount_t	ne_ref;		// refcount
> +	u32		ne_mask;	// FS_* mask from fsnotify callback
> +	struct dentry	*ne_dentry;	// dentry reference to target
> +	u32		ne_namelen;	// length of ne_name
> +	char		ne_name[];	// name of dentry being changed

Nit: checkpatch doesn't like the C++ comment style.


> +};
> +
> +static inline struct nfsd_notify_event *nfsd_notify_event_get(struct 
> nfsd_notify_event *ne)
> +{
> +	refcount_inc(&ne->ne_ref);
> +	return ne;
> +}
> +
> +static inline void nfsd_notify_event_put(struct nfsd_notify_event *ne)
> +{
> +	if (refcount_dec_and_test(&ne->ne_ref)) {
> +		dput(ne->ne_dentry);
> +		kfree(ne);
> +	}
> +}
> +
> +/*
> + * Represents a directory delegation. The callback is for handling 
> CB_NOTIFYs.
> + * As notifications from fsnotify come in, allocate a new event, take 
> the ncn_lock,
> + * and add it to the ncn_evt queue. The CB_NOTIFY prepare handler will 
> take the
> + * lock, clean out the list and process it.
> + */
> +struct nfsd4_cb_notify {
> +	spinlock_t			ncn_lock;	// protects the evt queue and count
> +	int				ncn_evt_cnt;	// count of events in ncn_evt
> +	int				ncn_nf_cnt;	// count of valid entries in ncn_nf
> +	struct nfsd_notify_event	*ncn_evt[NOTIFY4_EVENT_QUEUE_SIZE]; // list 
> of events
> +	struct page			*ncn_pages[NOTIFY4_PAGE_ARRAY_SIZE]; // for encoding
> +	struct notify4			*ncn_nf;	// array of notify4's to be sent
> +	struct nfsd4_callback		ncn_cb;		// notify4 callback
> +};

Ditto.


-- 
Chuck Lever