cifs: nosharesock should not share socket with future sessions

Today, when a new mount is done with nosharesock, we ensure
that we don't select an existing matching session. However,
we don't mark the connection as nosharesock, which means that
those could be shared with future sessions.

Fixed it with this commit. Also printing this info in DebugData.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/cifs_debug.c

@@ -358,6 +358,8 @@ static int cifs_debug_data_proc_show(struct seq_file *m, void *v)
 			seq_printf(m, " signed");
 		if (server->posix_ext_supported)
 			seq_printf(m, " posix");
+		if (server->nosharesock)
+			seq_printf(m, " nosharesock");
 
 		if (server->rdma)
 			seq_printf(m, "\nRDMA ");

fs/cifs/cifsglob.h

@@ -592,6 +592,7 @@ struct TCP_Server_Info {
 	struct list_head pending_mid_q;
 	bool noblocksnd;		/* use blocking sendmsg */
 	bool noautotune;		/* do not autotune send buf sizes */
+	bool nosharesock;
 	bool tcp_nodelay;
 	unsigned int credits;  /* send no more requests at once */
 	unsigned int max_credits; /* can override large 32000 default at mnt */

fs/cifs/connect.c

@@ -1217,7 +1217,13 @@ static int match_server(struct TCP_Server_Info *server, struct smb3_fs_context *
 {
 	struct sockaddr *addr = (struct sockaddr *)&ctx->dstaddr;
 
-	if (ctx->nosharesock)
+	if (ctx->nosharesock) {
+		server->nosharesock = true;
+		return 0;
+	}
+
+	/* this server does not share socket */
+	if (server->nosharesock)
 		return 0;
 
 	/* If multidialect negotiation see if existing sessions match one */