[v1,13/13] cifs: introduce the CifsInvalidCredentials session state

diff --git a/fs/cifs/cifs_debug.c b/fs/cifs/cifs_debug.c
index 276e4b5ea8e0..c03a445e95bc 100644
--- a/fs/cifs/cifs_debug.c
+++ b/fs/cifs/cifs_debug.c
@@ -392,6 +392,8 @@  static int cifs_debug_data_proc_show(struct seq_file *m, void *v)
 
 			/* dump session id helpful for use with network trace */
 			seq_printf(m, " SessionId: 0x%llx", ses->Suid);
+			if (ses->status == CifsInvalidCredentials)
+				seq_printf(m, " InvalidCredentials!");
 			if (ses->session_flags & SMB2_SESSION_FLAG_ENCRYPT_DATA)
 				seq_puts(m, " encrypted");
 			if (ses->sign)
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 46ebaf3f0824..9e2e5fa2cdff 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -650,6 +650,7 @@  static void cifs_umount_begin(struct super_block *sb)
 	/* cancel_notify_requests(tcon); */
 	if (tcon->ses && tcon->ses->server) {
 		cifs_dbg(FYI, "wake up tasks now - umount begin not complete\n");
+		wake_up_all(&tcon->ses->server->demultiplex_q);
 		wake_up_all(&tcon->ses->server->request_q);
 		wake_up_all(&tcon->ses->server->response_q);
 		msleep(1); /* yield */
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 8393ed7ebf96..4494b35fa5c5 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -114,7 +114,8 @@  enum statusEnum {
 	CifsGood,
 	CifsExiting,
 	CifsNeedReconnect,
-	CifsNeedNegotiate
+	CifsNeedNegotiate,
+	CifsInvalidCredentials,
 };
 
 enum securityEnum {
@@ -687,6 +688,7 @@  struct TCP_Server_Info {
 #endif
 	wait_queue_head_t response_q;
 	wait_queue_head_t request_q; /* if more than maxmpx to srvr must block*/
+	wait_queue_head_t demultiplex_q;
 	struct list_head pending_mid_q;
 	bool noblocksnd;		/* use blocking sendmsg */
 	bool noautotune;		/* do not autotune send buf sizes */
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 7f4be85b7cc9..39c0a5154eb9 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -480,6 +480,65 @@  static inline int reconn_setup_dfs_targets(struct cifs_sb_info *cifs_sb,
 }
 #endif
 
+static bool
+server_should_poll_for_responses(struct TCP_Server_Info *server)
+{
+	switch (server->tcpStatus) {
+	case CifsNew:
+		return false;
+	case CifsExiting:
+		return false;
+	case CifsGood:
+		return true;
+	case CifsNeedReconnect:
+		return false;
+	case CifsNeedNegotiate:
+		return true;
+	case CifsInvalidCredentials:
+		/*
+		 * Only a session should have this state
+		 */
+		WARN(true, "BUG! server->tcpStatus=CifsInvalidCredentials\n");
+		return false;
+	}
+
+	WARN(true, "Unhandled server->tcpStatus=%u\n", server->tcpStatus);
+	return false;
+}
+
+static bool
+server_should_reconnect(struct TCP_Server_Info *server)
+{
+	struct cifs_ses *ses;
+	size_t num_valid = 0;
+	size_t num_invalid = 0;
+
+	/*
+	 * If we are in disconnected state, waiting for a reconnect,
+	 * we should only try to reconnect if there's a chance
+	 * of success, that's not the case of all sessions
+	 * are have invalid credentials.
+	 */
+	if (server->tcpStatus != CifsNeedReconnect)
+		return false;
+
+	spin_lock(&cifs_tcp_ses_lock);
+	list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
+		if (ses->status != CifsInvalidCredentials) {
+			num_valid++;
+		} else {
+			num_invalid++;
+		}
+	}
+	spin_unlock(&cifs_tcp_ses_lock);
+
+	if (num_invalid == 0 || num_valid != 0) {
+		return true;
+	}
+
+	return false;
+}
+
 /*
  * cifs tcp session reconnection
  *
@@ -617,6 +676,17 @@  cifs_reconnect(struct TCP_Server_Info *server)
 		try_to_freeze();
 
 		mutex_lock(&server->srv_mutex);
+
+		if (!server_should_reconnect(server)) {
+			cifs_dbg(VFS,
+				 "Server %s was disconnected. "
+				 "We should NOT reconnect...\n",
+				 server->hostname);
+			rc = -ECONNABORTED;
+			mutex_unlock(&server->srv_mutex);
+			break;
+		}
+
 		/*
 		 * Set up next DFS target server (if any) for reconnect. If DFS
 		 * feature is disabled, then we will retry last server we
@@ -669,8 +739,17 @@  cifs_reconnect(struct TCP_Server_Info *server)
 
 	put_tcp_super(sb);
 #endif
-	if (server->tcpStatus == CifsNeedNegotiate)
-		mod_delayed_work(cifsiod_wq, &server->echo, 0);
+	if (server->tcpStatus == CifsNeedNegotiate) {
+		/* unfreeze the demultiplex thread */
+		wake_up_all(&server->demultiplex_q);
+		/*
+		 * schedule a immediate reconnect of sessions
+		 * and tcons.
+		 */
+		mod_delayed_work(cifsiod_wq, &server->reconnect, 0);
+		/* reset the echo timer into the future. */
+		mod_delayed_work(cifsiod_wq, &server->echo, server->echo_interval);
+	}
 
 	wake_up(&server->response_q);
 	return rc;
@@ -872,6 +951,19 @@  cifs_readv_from_socket(struct TCP_Server_Info *server, struct msghdr *smb_msg)
 	for (total_read = 0; msg_data_left(smb_msg); total_read += length) {
 		try_to_freeze();
 
+		if (server_should_reconnect(server)) {
+			cifs_dbg(VFS, "Server %s was disconnected. Reconnecting...\n",
+				 server->hostname);
+			cifs_reconnect(server);
+			wake_up(&server->response_q);
+			return -ECONNABORTED;
+		}
+
+		if (!server_should_poll_for_responses(server)) {
+			cifs_dbg(FYI, "Only invalid credential sessions\n");
+			return -ECONNABORTED;
+		}
+
 		/* reconnect if no credits and no requests in flight */
 		if (zero_credits(server)) {
 			cifs_reconnect(server);
@@ -1222,6 +1314,22 @@  smb2_add_credits_from_hdr(char *buffer, struct TCP_Server_Info *server)
 	}
 }
 
+static bool cifs_demultiplex_thread_should_block(struct TCP_Server_Info *server)
+{
+	if (server->tcpStatus == CifsExiting) {
+		return false;
+	}
+
+	if (server_should_reconnect(server)) {
+		return false;
+	}
+
+	if (server_should_poll_for_responses(server)) {
+		return false;
+	}
+
+	return true;
+}
 
 static int
 cifs_demultiplex_thread(void *p)
@@ -1248,6 +1356,11 @@  cifs_demultiplex_thread(void *p)
 		if (try_to_freeze())
 			continue;
 
+		wait_event_freezable(server->demultiplex_q,
+				!cifs_demultiplex_thread_should_block(server));
+		if (server->tcpStatus == CifsExiting)
+			break;
+
 		if (!allocate_buffers(server))
 			continue;
 
@@ -2880,6 +2993,7 @@  cifs_get_tcp_session(struct smb_vol *volume_info)
 	tcp_ses->credits = 1;
 	init_waitqueue_head(&tcp_ses->response_q);
 	init_waitqueue_head(&tcp_ses->request_q);
+	init_waitqueue_head(&tcp_ses->demultiplex_q);
 	INIT_LIST_HEAD(&tcp_ses->pending_mid_q);
 	mutex_init(&tcp_ses->srv_mutex);
 	memcpy(tcp_ses->workstation_RFC1001_name,
@@ -2967,6 +3081,13 @@  cifs_get_tcp_session(struct smb_vol *volume_info)
 
 	cifs_fscache_get_client_cookie(tcp_ses);
 
+	/* unfreeze the demultiplex thread */
+	wake_up_all(&tcp_ses->demultiplex_q);
+	/*
+	 * we let the caller use cifs_connect_session_locked()
+	 * (directly or via cifs_get_smb_ses() and don't
+	 * schedule the reconnect timer.
+	 */
 	/* queue echo request delayed work */
 	queue_delayed_work(cifsiod_wq, &tcp_ses->echo, tcp_ses->echo_interval);
 
@@ -5454,6 +5575,10 @@  cifs_connect_session_locked(const unsigned int xid,
 {
 	int rc;
 
+	if (ses->status == CifsInvalidCredentials) {
+		return -EKEYREVOKED;
+	}
+
 	if (ses->server->tcpStatus == CifsNeedReconnect) {
 		return -EHOSTDOWN;
 	}
@@ -5463,7 +5588,12 @@  cifs_connect_session_locked(const unsigned int xid,
 		cifs_dbg(FYI, "Session needs reconnect\n");
 		rc = cifs_setup_session(xid, ses, nls_info);
 		if ((rc == -EACCES) && !retry) {
-			return -EHOSTDOWN;
+			cifs_dbg(VFS,
+				 "SessionSetup to Server %s failed, "
+				 "marking as CifsInvalidCredentials/EKEYREVOKED\n",
+				 ses->server->hostname);
+			ses->status = CifsInvalidCredentials;
+			return -EKEYREVOKED;
 		}
 	}
 
@@ -5505,6 +5635,10 @@  cifs_tcon_reconnect(struct cifs_tcon *tcon,
 
 	retries = server->nr_targets;
 
+	if (ses->status == CifsInvalidCredentials) {
+		return -EKEYREVOKED;
+	}
+
 	/*
 	 * Give demultiplex thread up to 10 seconds to each target available for
 	 * reconnect -- should be greater than cifs socket timeout which is 7
@@ -5515,6 +5649,7 @@  cifs_tcon_reconnect(struct cifs_tcon *tcon,
 			return -EAGAIN;
 		}
 
+		wake_up_all(&server->demultiplex_q);
 		rc = wait_event_interruptible_timeout(server->response_q,
 						      (server->tcpStatus != CifsNeedReconnect),
 						      10 * HZ);
@@ -5543,6 +5678,10 @@  cifs_tcon_reconnect(struct cifs_tcon *tcon,
 		retries = server->nr_targets;
 	}
 
+	if (ses->status == CifsInvalidCredentials) {
+		return -EKEYREVOKED;
+	}
+
 	if (!ses->need_reconnect && !tcon->need_reconnect)
 		return 0;