nfsd4: make recall callback an asynchronous rpc

As with the probe, this removes the need for another kthread.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

fs/nfsd/nfs4callback.c

@@ -494,45 +494,69 @@ nfsd4_probe_callback(struct nfs4_client *clp)
 	do_probe_callback(clp);
 }
 
-/*
- * called with dp->dl_count inc'ed.
- */
-void
-nfsd4_cb_recall(struct nfs4_delegation *dp)
+static void nfsd4_cb_recall_done(struct rpc_task *task, void *calldata)
 {
+	struct nfs4_delegation *dp = calldata;
 	struct nfs4_client *clp = dp->dl_client;
-	struct rpc_clnt *clnt = clp->cl_cb_conn.cb_client;
-	struct rpc_message msg = {
-		.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_RECALL],
-		.rpc_argp = dp,
-		.rpc_cred = clp->cl_cb_conn.cb_cred
-	};
-	int status = 0;
 
-	dp->dl_retries = 1;
-	status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT);
-	while (dp->dl_retries--) {
-		switch (status) {
+	switch (task->tk_status) {
 	case -EIO:
 		/* Network partition? */
 		atomic_set(&clp->cl_cb_conn.cb_set, 0);
+		warn_no_callback_path(clp, task->tk_status);
 	case -EBADHANDLE:
 	case -NFS4ERR_BAD_STATEID:
 		/* Race: client probably got cb_recall
 		 * before open reply granting delegation */
 		break;
 	default:
-				goto out_put_cred;
+		/* success, or error we can't handle */
+		return;
 	}
-		ssleep(2);
-		status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFT);
+	if (dp->dl_retries--) {
+		rpc_delay(task, 2*HZ);
+		task->tk_status = 0;
+		rpc_restart_call(task);
+	} else {
+		atomic_set(&clp->cl_cb_conn.cb_set, 0);
+		warn_no_callback_path(clp, task->tk_status);
 	}
-out_put_cred:
-	/*
-	 * Success or failure, now we're either waiting for lease expiration
-	 * or deleg_return.
+}
+
+static void nfsd4_cb_recall_release(void *calldata)
+{
+	struct nfs4_delegation *dp = calldata;
+	struct nfs4_client *clp = dp->dl_client;
+
+	nfs4_put_delegation(dp);
+	put_nfs4_client(clp);
+}
+
+static const struct rpc_call_ops nfsd4_cb_recall_ops = {
+	.rpc_call_done = nfsd4_cb_recall_done,
+	.rpc_release = nfsd4_cb_recall_release,
+};
+
+/*
+ * called with dp->dl_count inc'ed.
  */
+void
+nfsd4_cb_recall(struct nfs4_delegation *dp)
+{
+	struct nfs4_client *clp = dp->dl_client;
+	struct rpc_clnt *clnt = clp->cl_cb_conn.cb_client;
+	struct rpc_message msg = {
+		.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_RECALL],
+		.rpc_argp = dp,
+		.rpc_cred = clp->cl_cb_conn.cb_cred
+	};
+	int status;
+
+	dp->dl_retries = 1;
+	status = rpc_call_async(clnt, &msg, RPC_TASK_SOFT,
+				&nfsd4_cb_recall_ops, dp);
+	if (status) {
 		put_nfs4_client(clp);
 		nfs4_put_delegation(dp);
-	return;
+	}
 }

fs/nfsd/nfs4state.c

@@ -2059,19 +2059,6 @@ nfs4_file_downgrade(struct file *filp, unsigned int share_access)
 	}
 }
 
-/*
- * Recall a delegation
- */
-static int
-do_recall(void *__dp)
-{
-	struct nfs4_delegation *dp = __dp;
-
-	dp->dl_file->fi_had_conflict = true;
-	nfsd4_cb_recall(dp);
-	return 0;
-}
-
 /*
  * Spawn a thread to perform a recall on the delegation represented
  * by the lease (file_lock)
@@ -2083,8 +2070,7 @@ do_recall(void *__dp)
 static
 void nfsd_break_deleg_cb(struct file_lock *fl)
 {
-	struct nfs4_delegation *dp=  (struct nfs4_delegation *)fl->fl_owner;
-	struct task_struct *t;
+	struct nfs4_delegation *dp = (struct nfs4_delegation *)fl->fl_owner;
 
 	dprintk("NFSD nfsd_break_deleg_cb: dp %p fl %p\n",dp,fl);
 	if (!dp)
@@ -2112,16 +2098,8 @@ void nfsd_break_deleg_cb(struct file_lock *fl)
 	 */
 	fl->fl_break_time = 0;
 
-	t = kthread_run(do_recall, dp, "%s", "nfs4_cb_recall");
-	if (IS_ERR(t)) {
-		struct nfs4_client *clp = dp->dl_client;
-
-		printk(KERN_INFO "NFSD: Callback thread failed for "
-			"for client (clientid %08x/%08x)\n",
-			clp->cl_clientid.cl_boot, clp->cl_clientid.cl_id);
-		put_nfs4_client(dp->dl_client);
-		nfs4_put_delegation(dp);
-	}
+	dp->dl_file->fi_had_conflict = true;
+	nfsd4_cb_recall(dp);
 }
 
 /*