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

[Dai Ngo <dai.ngo@oracle.com>]

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
hand out delegations for new requests.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
---
 fs/nfsd/nfs4state.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index fdc95bfbfbb6..a0bd6f6b994d 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -130,6 +130,7 @@ static const struct nfsd4_callback_ops nfsd4_cb_notify_lock_ops;
 static const struct nfsd4_callback_ops nfsd4_cb_getattr_ops;
 
 static struct workqueue_struct *laundry_wq;
+static void deleg_reaper(struct nfsd_net *nn);
 
 int nfsd4_create_laundry_wq(void)
 {
@@ -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);
 }
-- 
2.39.3