1 files changed, 42 insertions, 6 deletions

diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 243d17696f06..cbb0d55c1267 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -166,8 +166,12 @@ cifs_reconnect_tcon(struct cifs_tcon *tcon, int smb_command)
 		retries = server->nr_targets;
 	}
 
-	if (!ses->need_reconnect && !tcon->need_reconnect)
+	spin_lock(&ses->chan_lock);
+	if (!cifs_chan_needs_reconnect(ses, server) && !tcon->need_reconnect) {
+		spin_unlock(&ses->chan_lock);
 		return 0;
+	}
+	spin_unlock(&ses->chan_lock);
 
 	nls_codepage = load_nls_default();
 
@@ -188,8 +192,25 @@ cifs_reconnect_tcon(struct cifs_tcon *tcon, int smb_command)
 		goto out;
 	}
 
+	/*
+	 * need to prevent multiple threads trying to simultaneously
+	 * reconnect the same SMB session
+	 */
+	spin_lock(&ses->chan_lock);
+	if (!cifs_chan_needs_reconnect(ses, server)) {
+		spin_unlock(&ses->chan_lock);
+		/* this just means that we only need to tcon */
+		if (tcon->need_reconnect)
+			goto skip_sess_setup;
+
+		rc = -EHOSTDOWN;
+		mutex_unlock(&ses->session_mutex);
+		goto out;
+	}
+	spin_unlock(&ses->chan_lock);
+
 	rc = cifs_negotiate_protocol(0, ses);
-	if (rc == 0 && ses->need_reconnect)
+	if (!rc)
 		rc = cifs_setup_session(0, ses, nls_codepage);
 
 	/* do we need to reconnect tcon? */
@@ -198,6 +219,7 @@ cifs_reconnect_tcon(struct cifs_tcon *tcon, int smb_command)
 		goto out;
 	}
 
+skip_sess_setup:
 	cifs_mark_open_files_invalid(tcon);
 	rc = cifs_tree_connect(0, tcon, nls_codepage);
 	mutex_unlock(&ses->session_mutex);
@@ -337,8 +359,13 @@ static int
 smb_init_no_reconnect(int smb_command, int wct, struct cifs_tcon *tcon,
 			void **request_buf, void **response_buf)
 {
-	if (tcon->ses->need_reconnect || tcon->need_reconnect)
+	spin_lock(&tcon->ses->chan_lock);
+	if (cifs_chan_needs_reconnect(tcon->ses, tcon->ses->server) ||
+	    tcon->need_reconnect) {
+		spin_unlock(&tcon->ses->chan_lock);
 		return -EHOSTDOWN;
+	}
+	spin_unlock(&tcon->ses->chan_lock);
 
 	return __smb_init(smb_command, wct, tcon, request_buf, response_buf);
 }
@@ -600,8 +627,12 @@ CIFSSMBTDis(const unsigned int xid, struct cifs_tcon *tcon)
 	 * the tcon is no longer on the list, so no need to take lock before
 	 * checking this.
 	 */
-	if ((tcon->need_reconnect) || (tcon->ses->need_reconnect))
-		return 0;
+	spin_lock(&tcon->ses->chan_lock);
+	if ((tcon->need_reconnect) || CIFS_ALL_CHANS_NEED_RECONNECT(tcon->ses)) {
+		spin_unlock(&tcon->ses->chan_lock);
+		return -EIO;
+	}
+	spin_unlock(&tcon->ses->chan_lock);
 
 	rc = small_smb_init(SMB_COM_TREE_DISCONNECT, 0, tcon,
 			    (void **)&smb_buffer);
@@ -696,9 +727,14 @@ CIFSSMBLogoff(const unsigned int xid, struct cifs_ses *ses)
 		return -EIO;
 
 	mutex_lock(&ses->session_mutex);
-	if (ses->need_reconnect)
+	spin_lock(&ses->chan_lock);
+	if (CIFS_ALL_CHANS_NEED_RECONNECT(ses)) {
+		spin_unlock(&ses->chan_lock);
 		goto session_already_dead; /* no need to send SMBlogoff if uid
 					      already closed due to reconnect */
+	}
+	spin_unlock(&ses->chan_lock);
+
 	rc = small_smb_init(SMB_COM_LOGOFF_ANDX, 2, NULL, (void **)&pSMB);
 	if (rc) {
 		mutex_unlock(&ses->session_mutex);