cifs: Handle -EINPROGRESS only when noblockcnt is set

We only want to avoid blocking in connect when mounting SMB root
filesystems, otherwise bail out from generic_ip_connect() so cifs.ko
can perform any reconnect failover appropriately.

This fixes DFS failover/reconnection tests in upstream buildbot.

Fixes: 8eecd1c2 ("cifs: Add support for root file systems")
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/connect.c

@@ -3882,8 +3882,12 @@ generic_ip_connect(struct TCP_Server_Info *server)
 
 	rc = socket->ops->connect(socket, saddr, slen,
 				  server->noblockcnt ? O_NONBLOCK : 0);
-
-	if (rc == -EINPROGRESS)
+	/*
+	 * When mounting SMB root file systems, we do not want to block in
+	 * connect. Otherwise bail out and then let cifs_reconnect() perform
+	 * reconnect failover - if possible.
+	 */
+	if (server->noblockcnt && rc == -EINPROGRESS)
 		rc = 0;
 	if (rc < 0) {
 		cifs_dbg(FYI, "Error %d connecting to server\n", rc);