Re: [PATCH v2 1/1] NFSD: send OP_CB_RECALL_ANY to clients when number of delegations reaches its limit

[Jeff Layton <jlayton@kernel.org>]

On Sun, 2024-03-03 at 14:23 -0800, Dai Ngo wrote:
> The NFS server should ask clients to voluntarily return unused
> delegations when the number of granted delegations reaches the
> max_delegations. This is so that the server can continue to
> grant delegations for new requests.
> 
> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
> ---
>  fs/nfsd/nfs4state.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> v2: move declaration of deleg_reaper() up to other forward
>     declarations in the file.
> 
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index fdc95bfbfbb6..961000261b3e 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -87,6 +87,7 @@ static void nfs4_free_ol_stateid(struct nfs4_stid *stid);
>  void nfsd4_end_grace(struct nfsd_net *nn);
>  static void _free_cpntf_state_locked(struct nfsd_net *nn, struct nfs4_cpntf_state *cps);
>  static void nfsd4_file_hash_remove(struct nfs4_file *fi);
> +static void deleg_reaper(struct nfsd_net *nn);
>  
>  /* Locking: */
>  
> @@ -6550,6 +6551,8 @@ nfs4_laundromat(struct nfsd_net *nn)
>  	/* service the server-to-server copy delayed unmount list */
>  	nfsd4_ssc_expire_umount(nn);
>  #endif
> +	if (atomic_long_read(&num_delegations) >= max_delegations)
> +		deleg_reaper(nn);
>  out:
>  	return max_t(time64_t, lt.new_timeo, NFSD_LAUNDROMAT_MINTIMEOUT);
>  }

Seems like a reasonable thing to do:

Reviewed-by: Jeff Layton <jlayton@kernel.org>