Break client/server out of waiting network replies

If there is a forced unmount we call _net_shutdown from
umount_begin in order to tell the server and clients to
break out of pending network replies. We then add the call
to abort within the shutdown_worker since most of the mucking
with send and resend queues are all done there.

Signed-off-by: Bryant G. Duffy-Ly <bduffyly@versity.com>

kmod/src/client.c

@@ -668,3 +668,11 @@ void scoutfs_client_destroy(struct super_block *sb)
 	kfree(client);
 	sbi->client_info = NULL;
 }
+
+void scoutfs_client_net_shutdown(struct super_block *sb)
+{
+	struct client_info *client = SCOUTFS_SB(sb)->client_info;
+
+	if (client && client->conn)
+		scoutfs_net_shutdown(sb, client->conn);
+}

kmod/src/client.h

@@ -35,6 +35,7 @@ int scoutfs_client_clear_volopt(struct super_block *sb, struct scoutfs_volume_op
 int scoutfs_client_resize_devices(struct super_block *sb, struct scoutfs_net_resize_devices *nrd);
 int scoutfs_client_statfs(struct super_block *sb, struct scoutfs_net_statfs *nst);
 
+void scoutfs_client_net_shutdown(struct super_block *sb);
 int scoutfs_client_setup(struct super_block *sb);
 void scoutfs_client_destroy(struct super_block *sb);
 

kmod/src/net.c

@@ -835,17 +835,9 @@ static void scoutfs_net_destroy_worker(struct work_struct *work)
 	if (conn->listening_conn && conn->notify_down)
 		conn->notify_down(sb, conn, conn->info, conn->rid);
 
-	/*
-	 * Usually networking is idle and we destroy pending sends, but when forcing unmount
-	 * we can have to wake up waiters by failing pending sends.
-	 */
 	list_splice_init(&conn->resend_queue, &conn->send_queue);
-	list_for_each_entry_safe(msend, tmp, &conn->send_queue, head) {
-		if (scoutfs_forcing_unmount(sb))
-			call_resp_func(sb, conn, msend->resp_func, msend->resp_data,
-				       NULL, 0, -ECONNABORTED);
+	list_for_each_entry_safe(msend, tmp, &conn->send_queue, head)
 		free_msend(ninf, msend);
-	}
 
 	/* accepted sockets are removed from their listener's list */
 	if (conn->listening_conn) {
@@ -1134,9 +1126,11 @@ static void scoutfs_net_shutdown_worker(struct work_struct *work)
 	struct net_info *ninf = SCOUTFS_SB(sb)->net_info;
 	struct scoutfs_net_connection *listener;
 	struct scoutfs_net_connection *acc_conn;
+	scoutfs_net_response_t resp_func;
 	struct message_send *msend;
 	struct message_send *tmp;
 	unsigned long delay;
+	void *resp_data;
 
 	trace_scoutfs_net_shutdown_work_enter(sb, 0, 0);
 	trace_scoutfs_conn_shutdown_start(conn);
@@ -1182,6 +1176,30 @@ static void scoutfs_net_shutdown_worker(struct work_struct *work)
 	/* and wait for accepted conn shutdown work to finish */
 	wait_event(conn->waitq, empty_accepted_list(conn));
 
+	/*
+	 * Forced unmount will cause net submit to fail once it's
+	 * started and it calls shutdown to interrupt any previous
+	 * senders waiting for a response.   The response callbacks can
+	 * do quite a lot of work so we're careful to call them outside
+	 * the lock.
+	 */
+	if (scoutfs_forcing_unmount(sb)) {
+		spin_lock(&conn->lock);
+		list_splice_tail_init(&conn->send_queue, &conn->resend_queue);
+		while ((msend = list_first_entry_or_null(&conn->resend_queue,
+							struct message_send, head))) {
+			resp_func = msend->resp_func;
+			resp_data = msend->resp_data;
+			free_msend(ninf, msend);
+			spin_unlock(&conn->lock);
+
+			call_resp_func(sb, conn, resp_func, resp_data, NULL, 0, -ECONNABORTED);
+
+			spin_lock(&conn->lock);
+		}
+		spin_unlock(&conn->lock);
+	}
+
 	spin_lock(&conn->lock);
 
 	/* greetings aren't resent across sockets */

kmod/src/super.c

@@ -271,6 +271,8 @@ static void scoutfs_umount_begin(struct super_block *sb)
 
 	scoutfs_warn(sb, "forcing unmount, can return errors and lose unsynced data");
 	sbi->forced_unmount = true;
+
+	scoutfs_client_net_shutdown(sb);
 }
 
 static const struct super_operations scoutfs_super_ops = {