cifs: do not disable interface polling on failure

When a server has multichannel enabled, we keep polling the server
for interfaces periodically. However, when this query fails, we
disable the polling. This can be problematic as it takes away the
chance for the server to start advertizing again.

This change reschedules the delayed work, even if the current call
failed. That way, multichannel sessions can recover.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/smb/client/connect.c

@@ -116,13 +116,9 @@ static void smb2_query_server_interfaces(struct work_struct *work)
 	rc = server->ops->query_server_interfaces(xid, tcon, false);
 	free_xid(xid);
 
-	if (rc) {
-		if (rc == -EOPNOTSUPP)
-			return;
-
+	if (rc)
 		cifs_dbg(FYI, "%s: failed to query server interfaces: %d\n",
 				__func__, rc);
-	}
 
 	queue_delayed_work(cifsiod_wq, &tcon->query_interfaces,
 			   (SMB_INTERFACE_POLL_INTERVAL * HZ));

fs/smb/client/smb2pdu.c

@@ -424,6 +424,10 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon,
 		free_xid(xid);
 		ses->flags &= ~CIFS_SES_FLAGS_PENDING_QUERY_INTERFACES;
 
+		/* regardless of rc value, setup polling */
+		queue_delayed_work(cifsiod_wq, &tcon->query_interfaces,
+				   (SMB_INTERFACE_POLL_INTERVAL * HZ));
+
 		mutex_unlock(&ses->session_mutex);
 
 		if (rc == -EOPNOTSUPP && ses->chan_count > 1) {
@@ -444,11 +448,8 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon,
 		if (ses->chan_max > ses->chan_count &&
 		    ses->iface_count &&
 		    !SERVER_IS_CHAN(server)) {
-			if (ses->chan_count == 1) {
+			if (ses->chan_count == 1)
 				cifs_server_dbg(VFS, "supports multichannel now\n");
-				queue_delayed_work(cifsiod_wq, &tcon->query_interfaces,
-						 (SMB_INTERFACE_POLL_INTERVAL * HZ));
-			}
 
 			cifs_try_adding_channels(ses);
 		}