cifs: Fix lookup of SMB connections on multichannel

With the addition of SMB session channels, we introduced new TCP
server pointers that have no sessions or tcons associated with them.

In this case, when we started looking for TCP connections, we might
end up picking session channel rather than the master connection,
hence failing to get either a session or a tcon.

In order to fix that, this patch introduces a new "is_channel" field
to TCP_Server_Info structure so we can skip session channels during
lookup of connections.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 5b976e0..fd0262c 100644 (file)
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -777,6 +777,7 @@ struct TCP_Server_Info {
         */
        int nr_targets;
        bool noblockcnt; /* use non-blocking connect() */
+       bool is_channel; /* if a session channel */
 };
 
 struct cifs_credits {

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 86d1bae..05ea0e2 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2712,7 +2712,11 @@ cifs_find_tcp_session(struct smb_vol *vol)
 
        spin_lock(&cifs_tcp_ses_lock);
        list_for_each_entry(server, &cifs_tcp_ses_list, tcp_ses_list) {
-               if (!match_server(server, vol))
+               /*
+                * Skip ses channels since they're only handled in lower layers
+                * (e.g. cifs_send_recv).
+                */
+               if (server->is_channel || !match_server(server, vol))
                        continue;
 
                ++server->srv_count;

diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index fb3bdc4..d951373 100644 (file)
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -213,6 +213,9 @@ cifs_ses_add_channel(struct cifs_ses *ses, struct cifs_server_iface *iface)
                chan->server = NULL;
                goto out;
        }
+       spin_lock(&cifs_tcp_ses_lock);
+       chan->server->is_channel = true;
+       spin_unlock(&cifs_tcp_ses_lock);
 
        /*
         * We need to allocate the server crypto now as we will need