ksmbd: mark SMB2_SESSION_EXPIRED to session when destroying previous session

Currently ksmbd exit connection as well destroying previous session.
When testing durable handle feaure, I found that
destroy_previous_session() should destroy only session, i.e. the
connection should be still alive. This patch mark SMB2_SESSION_EXPIRED
on the previous session to be destroyed later and not used anymore.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/smb/server/mgmt/user_session.c

@@ -156,7 +156,7 @@ void ksmbd_session_destroy(struct ksmbd_session *sess)
 	kfree(sess);
 }
 
-static struct ksmbd_session *__session_lookup(unsigned long long id)
+struct ksmbd_session *__session_lookup(unsigned long long id)
 {
 	struct ksmbd_session *sess;
 
@@ -305,6 +305,31 @@ struct preauth_session *ksmbd_preauth_session_alloc(struct ksmbd_conn *conn,
 	return sess;
 }
 
+void destroy_previous_session(struct ksmbd_conn *conn,
+			      struct ksmbd_user *user, u64 id)
+{
+	struct ksmbd_session *prev_sess;
+	struct ksmbd_user *prev_user;
+
+	down_write(&sessions_table_lock);
+	down_write(&conn->session_lock);
+	prev_sess = __session_lookup(id);
+	if (!prev_sess || prev_sess->state == SMB2_SESSION_EXPIRED)
+		goto out;
+
+	prev_user = prev_sess->user;
+	if (!prev_user ||
+	    strcmp(user->name, prev_user->name) ||
+	    user->passkey_sz != prev_user->passkey_sz ||
+	    memcmp(user->passkey, prev_user->passkey, user->passkey_sz))
+		goto out;
+
+	prev_sess->state = SMB2_SESSION_EXPIRED;
+out:
+	up_write(&conn->session_lock);
+	up_write(&sessions_table_lock);
+}
+
 static bool ksmbd_preauth_session_id_match(struct preauth_session *sess,
 					   unsigned long long id)
 {

fs/smb/server/mgmt/user_session.h

@@ -88,8 +88,11 @@ struct ksmbd_session *ksmbd_session_lookup(struct ksmbd_conn *conn,
 int ksmbd_session_register(struct ksmbd_conn *conn,
 			   struct ksmbd_session *sess);
 void ksmbd_sessions_deregister(struct ksmbd_conn *conn);
+struct ksmbd_session *__session_lookup(unsigned long long id);
 struct ksmbd_session *ksmbd_session_lookup_all(struct ksmbd_conn *conn,
 					       unsigned long long id);
+void destroy_previous_session(struct ksmbd_conn *conn,
+			      struct ksmbd_user *user, u64 id);
 struct preauth_session *ksmbd_preauth_session_alloc(struct ksmbd_conn *conn,
 						    u64 sess_id);
 struct preauth_session *ksmbd_preauth_session_lookup(struct ksmbd_conn *conn,

fs/smb/server/smb2pdu.c

@@ -607,30 +607,6 @@ int smb2_check_user_session(struct ksmbd_work *work)
 	return -ENOENT;
 }
 
-static void destroy_previous_session(struct ksmbd_conn *conn,
-				     struct ksmbd_user *user, u64 id)
-{
-	struct ksmbd_session *prev_sess = ksmbd_session_lookup_slowpath(id);
-	struct ksmbd_user *prev_user;
-	struct channel *chann;
-	long index;
-
-	if (!prev_sess)
-		return;
-
-	prev_user = prev_sess->user;
-
-	if (!prev_user ||
-	    strcmp(user->name, prev_user->name) ||
-	    user->passkey_sz != prev_user->passkey_sz ||
-	    memcmp(user->passkey, prev_user->passkey, user->passkey_sz))
-		return;
-
-	prev_sess->state = SMB2_SESSION_EXPIRED;
-	xa_for_each(&prev_sess->ksmbd_chann_list, index, chann)
-		ksmbd_conn_set_exiting(chann->conn);
-}
-
 /**
  * smb2_get_name() - get filename string from on the wire smb format
  * @src:	source buffer