[PATCH 1/1] NFSD: cancel CB_RECALL_ANY call when nfs4_client is about to be destroyed

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

Currently when a nfs4_client is destroyed we wait for the cb_recall_any
callback to complete before proceed. This adds unnecessary delay to the
__destroy_client call if there is problem communicating with the client.

This patch addresses this issue by cancelling the CB_RECALL_ANY call from
the workqueue when the nfs4_client is about to be destroyed.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
---
 fs/nfsd/nfs4callback.c | 10 ++++++++++
 fs/nfsd/nfs4state.c    | 10 +++++++++-
 fs/nfsd/state.h        |  1 +
 3 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 87c9547989f6..e5b50c96be6a 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -1568,3 +1568,13 @@ bool nfsd4_run_cb(struct nfsd4_callback *cb)
 		nfsd41_cb_inflight_end(clp);
 	return queued;
 }
+
+void nfsd41_cb_recall_any_cancel(struct nfs4_client *clp)
+{
+	if (test_bit(NFSD4_CLIENT_CB_RECALL_ANY, &clp->cl_flags) &&
+			cancel_delayed_work(&clp->cl_ra->ra_cb.cb_work)) {
+		clear_bit(NFSD4_CLIENT_CB_RECALL_ANY, &clp->cl_flags);
+		atomic_add_unless(&clp->cl_rpc_users, -1, 0);
+		nfsd41_cb_inflight_end(clp);
+	}
+}
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 1a93c7fcf76c..0e1db57c9a19 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -2402,6 +2402,7 @@ __destroy_client(struct nfs4_client *clp)
 	}
 	nfsd4_return_all_client_layouts(clp);
 	nfsd4_shutdown_copy(clp);
+	nfsd41_cb_recall_any_cancel(clp);
 	nfsd4_shutdown_callback(clp);
 	if (clp->cl_cb_conn.cb_xprt)
 		svc_xprt_put(clp->cl_cb_conn.cb_xprt);
@@ -2980,6 +2981,12 @@ static void force_expire_client(struct nfs4_client *clp)
 	clp->cl_time = 0;
 	spin_unlock(&nn->client_lock);
 
+	/*
+	 * no need to send and wait for CB_RECALL_ANY
+	 * when client is about to be destroyed
+	 */
+	nfsd41_cb_recall_any_cancel(clp);
+
 	wait_event(expiry_wq, atomic_read(&clp->cl_rpc_users) == 0);
 	spin_lock(&nn->client_lock);
 	already_expired = list_empty(&clp->cl_lru);
@@ -6617,7 +6624,8 @@ deleg_reaper(struct nfsd_net *nn)
 		clp->cl_ra->ra_bmval[0] = BIT(RCA4_TYPE_MASK_RDATA_DLG) |
 						BIT(RCA4_TYPE_MASK_WDATA_DLG);
 		trace_nfsd_cb_recall_any(clp->cl_ra);
-		nfsd4_run_cb(&clp->cl_ra->ra_cb);
+		if (!nfsd4_run_cb(&clp->cl_ra->ra_cb))
+			clear_bit(NFSD4_CLIENT_CB_RECALL_ANY, &clp->cl_flags);
 	}
 }
 
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 01c6f3445646..259b4af7d226 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -735,6 +735,7 @@ extern void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *
 extern void nfsd4_init_cb(struct nfsd4_callback *cb, struct nfs4_client *clp,
 		const struct nfsd4_callback_ops *ops, enum nfsd4_cb_op op);
 extern bool nfsd4_run_cb(struct nfsd4_callback *cb);
+extern void nfsd41_cb_recall_any_cancel(struct nfs4_client *clp);
 extern int nfsd4_create_callback_queue(void);
 extern void nfsd4_destroy_callback_queue(void);
 extern void nfsd4_shutdown_callback(struct nfs4_client *);
-- 
2.39.3