Recent multichannel fixes for the client

Commit Message

Steve French Dec. 29, 2023, 3:20 p.m. UTC

Here is the set of important multichannel fixes that Shyam recently
sent out, ordered the way he requested (and a few updated with missing
tags as requested).  They are applied to cifs-2.6.git for-next now

Patch

From 27e1fd343f80168ff456785c2443136b6b7ca3cc Mon Sep 17 00:00:00 2001
From: Shyam Prasad N <[e-mail]>
Date: Fri, 29 Dec 2023 11:30:07 +0000
Subject: [PATCH 1/5] cifs: after disabling multichannel, mark tcon for
 reconnect

Once the server disables multichannel for an active multichannel
session, on the following reconnect, the client would reduce
the number of channels to 1. However, it could be the case that
the tree connect was active on one of these disabled channels.
This results in an unrecoverable state.

This change fixes that by making sure that whenever a channel
is being terminated, the session and tcon are marked for
reconnect too. This could mean a few redundant tree connect
calls to the server, but considering that this is not a frequent
event, we should be okay.

Fixes: ee1d21794e55 ("cifs: handle when server stops supporting multichannel")
Signed-off-by: Shyam Prasad N <[e-mail]>
Signed-off-by: Steve French <[e-mail]>
---
 fs/smb/client/connect.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c
index dd2a1fb65e71..560624189c8b 100644
--- a/fs/smb/client/connect.c
+++ b/fs/smb/client/connect.c
@@ -216,17 +216,21 @@  cifs_mark_tcp_ses_conns_for_reconnect(struct TCP_Server_Info *server,
 	/* If server is a channel, select the primary channel */
 	pserver = SERVER_IS_CHAN(server) ? server->primary_server : server;
 
+	/*
+	 * if the server has been marked for termination, there is a
+	 * chance that the remaining channels all need reconnect. To be
+	 * on the safer side, mark the session and trees for reconnect
+	 * for this scenario. This might cause a few redundant session
+	 * setup and tree connect requests, but it is better than not doing
+	 * a tree connect when needed, and all following requests failing
+	 */
+	if (server->terminate) {
+		mark_smb_session = true;
+		server = pserver;
+	}
 
 	spin_lock(&cifs_tcp_ses_lock);
 	list_for_each_entry_safe(ses, nses, &pserver->smb_ses_list, smb_ses_list) {
-		/*
-		 * if channel has been marked for termination, nothing to do
-		 * for the channel. in fact, we cannot find the channel for the
-		 * server. So safe to exit here
-		 */
-		if (server->terminate)
-			break;
-
 		/* check if iface is still active */
 		if (!cifs_chan_is_iface_active(ses, server))
 			cifs_chan_update_iface(ses, server);
-- 
2.40.1