On Tue, Apr 7, 2026, at 9:21 AM, Jeff Layton wrote:
> Add the necessary parts to accept a fsnotify callback for directory
> change event and create a CB_NOTIFY request for it. When a dir nfsd_file
> is created set a handle_event callback to handle the notification.
>
> Use that to allocate a nfsd_notify_event object and then hand off a
> reference to each delegation's CB_NOTIFY. If anything fails along the
> way, recall any affected delegations.
>
> Signed-off-by: Jeff Layton <[email protected]>
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index b2b8c454fc0f..339c3d0bb575 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -9796,3 +9887,118 @@ nfsd_get_dir_deleg(struct nfsd4_compound_state
> *cstate,
> put_nfs4_file(fp);
> return ERR_PTR(status);
> }
> +
> +static void
> +nfsd4_run_cb_notify(struct nfsd4_cb_notify *ncn)
> +{
> + struct nfs4_delegation *dp = container_of(ncn, struct
> nfs4_delegation, dl_cb_notify);
> +
> + if (test_and_set_bit(NFSD4_CALLBACK_RUNNING, &ncn->ncn_cb.cb_flags))
> + return;
> +
> + if (!refcount_inc_not_zero(&dp->dl_stid.sc_count))
> + clear_bit(NFSD4_CALLBACK_RUNNING, &ncn->ncn_cb.cb_flags);
> + else
> + nfsd4_run_cb(&ncn->ncn_cb);
> +}
> +
> +static struct nfsd_notify_event *
> +alloc_nfsd_notify_event(u32 mask, const struct qstr *q, struct dentry
> *dentry)
> +{
> + struct nfsd_notify_event *ne;
> +
> + ne = kmalloc(sizeof(*ne) + q->len + 1, GFP_KERNEL);
> + if (!ne)
> + return NULL;
> +
> + memcpy(&ne->ne_name, q->name, q->len);
> + refcount_set(&ne->ne_ref, 1);
> + ne->ne_mask = mask;
> + ne->ne_name[q->len] = '\0';
> + ne->ne_namelen = q->len;
> + ne->ne_dentry = dget(dentry);
> + return ne;
> +}
> +
> +static bool
> +should_notify_deleg(u32 mask, struct file_lease *fl)
> +{
> + /* Only nfsd leases */
> + if (fl->fl_lmops != &nfsd_lease_mng_ops)
> + return false;
> +
> + /* Skip if this event wasn't ignored by the lease */
> + if ((mask & FS_DELETE) && !(fl->c.flc_flags & FL_IGN_DIR_DELETE))
> + return false;
> + if ((mask & FS_CREATE) && !(fl->c.flc_flags & FL_IGN_DIR_CREATE))
> + return false;
> + if ((mask & FS_RENAME) && !(fl->c.flc_flags & FL_IGN_DIR_RENAME))
> + return false;
> +
> + return true;
> +}
For a cross-directory rename, vfs_rename calls try_break_deleg(old_dir,
LEASE_BREAK_DIR_DELETE, ...). A delegation with FL_IGN_DIR_DELETE
(subscribed to NOTIFY4_REMOVE_ENTRY) suppresses the lease break, which
is correct.
But fsnotify delivers FS_RENAME on old_dir, not FS_DELETE. In
should_notify_deleg(), the check (mask & FS_RENAME) &&
!(fl->c.flc_flags & FL_IGN_DIR_RENAME) fails, because the delegation
has FL_IGN_DIR_DELETE but not FL_IGN_DIR_RENAME. No notification is
sent.
IIUC, a client subscribed to NOTIFY4_REMOVE_ENTRY for old_dir sees
neither a lease break nor a CB_NOTIFY when a child is renamed out of
the directory. Is that behavior correct?
> +
> +static void
> +nfsd_recall_all_dir_delegs(const struct inode *dir)
> +{
> + struct file_lock_context *ctx = locks_inode_context(dir);
> + struct file_lock_core *flc;
> +
> + spin_lock(&ctx->flc_lock);
> + list_for_each_entry(flc, &ctx->flc_lease, flc_list) {
> + struct file_lease *fl = container_of(flc, struct file_lease, c);
> +
> + if (fl->fl_lmops == &nfsd_lease_mng_ops)
> + nfsd_break_deleg_cb(fl);
> + }
> + spin_unlock(&ctx->flc_lock);
> +}
> +
> +int
> +nfsd_handle_dir_event(u32 mask, const struct inode *dir, const void
> *data,
> + int data_type, const struct qstr *name)
> +{
> + struct dentry *dentry = fsnotify_data_dentry(data, data_type);
> + struct file_lock_context *ctx;
> + struct file_lock_core *flc;
> + struct nfsd_notify_event *evt;
> +
> + /* Don't do anything if this is not an expected event */
> + if (!(mask & (FS_CREATE|FS_DELETE|FS_RENAME)))
> + return 0;
> +
> + ctx = locks_inode_context(dir);
> + if (!ctx || list_empty(&ctx->flc_lease))
> + return 0;
> +
> + evt = alloc_nfsd_notify_event(mask, name, dentry);
> + if (!evt) {
> + nfsd_recall_all_dir_delegs(dir);
> + return 0;
> + }
> +
> + spin_lock(&ctx->flc_lock);
> + list_for_each_entry(flc, &ctx->flc_lease, flc_list) {
> + struct file_lease *fl = container_of(flc, struct file_lease, c);
> + struct nfs4_delegation *dp = flc->flc_owner;
> + struct nfsd4_cb_notify *ncn = &dp->dl_cb_notify;
> +
> + if (!should_notify_deleg(mask, fl))
> + continue;
> +
> + spin_lock(&ncn->ncn_lock);
> + if (ncn->ncn_evt_cnt >= NOTIFY4_EVENT_QUEUE_SIZE) {
> + /* We're generating notifications too fast. Recall. */
> + spin_unlock(&ncn->ncn_lock);
> + nfsd_break_deleg_cb(fl);
> + continue;
> + }
> + ncn->ncn_evt[ncn->ncn_evt_cnt++] = nfsd_notify_event_get(evt);
> + spin_unlock(&ncn->ncn_lock);
> +
> + nfsd4_run_cb_notify(ncn);
> + }
> + spin_unlock(&ctx->flc_lock);
> + nfsd_notify_event_put(evt);
> + return 0;
> +}
--
Chuck Lever
