From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7D938C1B0F2 for ; Wed, 20 Jun 2018 09:14:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 38C7E20652 for ; Wed, 20 Jun 2018 09:14:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 38C7E20652 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arndb.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754827AbeFTJOk (ORCPT ); Wed, 20 Jun 2018 05:14:40 -0400 Received: from mout.kundenserver.de ([212.227.126.131]:44455 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754299AbeFTIdr (ORCPT ); Wed, 20 Jun 2018 04:33:47 -0400 Received: from wuerfel.lan ([95.208.111.237]) by mrelayeu.kundenserver.de (mreue005 [212.227.15.129]) with ESMTPA (Nemesis) id 0LrGGm-1gChuk1us0-0135sI; Wed, 20 Jun 2018 10:33:42 +0200 From: Arnd Bergmann To: David Howells Cc: y2038@lists.linaro.org, Arnd Bergmann , linux-cachefs@redhat.com, linux-kernel@vger.kernel.org Subject: [PATCH] cachefiles: avoid deprecated get_seconds() Date: Wed, 20 Jun 2018 10:31:10 +0200 Message-Id: <20180620083339.766780-1-arnd@arndb.de> X-Mailer: git-send-email 2.9.0 X-Provags-ID: V03:K1:5u9IqHPzy3OlmTSEzyeONOP86GAngA6lrWFV9i7lcKSXY2Edgx7 X/9UXKcQEMZP6Jy35BvMYKRsKGKDGj0560PJrHGvsO0H5OUBlNavWiQwCmM2t3wp9dQ7nWr XMrnKkShGcZXFJAw7nj6kByAYg+hk0Y+Eytw9Z0fhQPTtqhcdYfmXGWlRrNY3KusvXOz2bn gXIzB4kxsRjw+XORDD4gA== X-UI-Out-Filterresults: notjunk:1;V01:K0:cAuOoTufQ3I=:npO72s62Ui7Rz2uDl7mhS5 jmkkB2nJNG0jc1JtDprUsarxkQ69UVWrPhWgnNXzbBpNeaAPWoRlE7CqnlEo5nYVF522jzjEb emdoSbmM14lBkRB54xhVCesUorT33/kh5lONckrwxydLSpEPehBNJ25HxUxjHQli1nkTIiILB ztO6icLWx9+xDSbX+06LnNtTnsxnEPOawnajOXqYnkqI7rnrbpQ8bQnzf12t/VbH3HdAenYEV 2opUU+1ri7yD8CW+bGKKhJgIvPJ5NwMCSPgC/OZTyO1p7L1u+5gxADOKtAw1i9LCq+Kx/E9CI NC/qEoOH1MSQvBvjCZ+CJnUWibDj0KAUreC89eW1cO9uAl3q+4ih1EPWJdMq3E8My2U0uqPUI MJrrPwJmdjLQTuvxnjmnbz7FqhaqUAmdw5OOWrKgQ8KeHTwfrTMdKit1GU/qsUHoQAWuC2WmH WZrVdRbYjYmy9cakC0lFeOqUm3sZKrTwC9CuHZFOtF2tdTq1ecU5JH8ukzwQfUDciDjAL0eLW KMOM/9b82OSCTKdfJnemIpKUiYq9KfzPYmiRdF0SO0TeGUgB3ialtM/WgbHEQ+wYGCbCY82pE XAtUnjuQKV/5MGdbB84TTYWSGHmIMwaALmO4kvvCzBlPLcIMdxAp4Ds0qdfR4aYmDnkorLtdm XbXH/qPDKx1IPOBwNd1JD/aXD71lmkMJGH75WK+pG+vHY6iXChIBqMFMbpjwL2ioq77M= Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org get_seconds() returns an unsigned long can overflow on some architectures and is deprecated because of that. In cachefs, we cast that number to a a 32-bit integer, which will overflow in year 2106 on all architectures. The overflow probably isn't harmful in the end, since the timestamps are only used to make the file names unique, but they don't strictly have to be in monotonically increasing order. Moving to ktime_get_real_seconds() avoids the deprecated interface, the question is whether we should still truncate to 32 bits. In this patch, I decided to not overflow, but instead to extend the file names using the 64-bit timestamp, so they will be 17 characters after 2106 rather than 16. Signed-off-by: Arnd Bergmann --- fs/cachefiles/namei.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c index ab0bbe93b398..5705e29d4506 100644 --- a/fs/cachefiles/namei.c +++ b/fs/cachefiles/namei.c @@ -297,7 +297,7 @@ static int cachefiles_bury_object(struct cachefiles_cache *cache, { struct dentry *grave, *trap; struct path path, path_to_graveyard; - char nbuffer[8 + 8 + 1]; + char nbuffer[16 + 8 + 1]; int ret; _enter(",'%pd','%pd'", dir, rep); @@ -336,8 +336,8 @@ static int cachefiles_bury_object(struct cachefiles_cache *cache, try_again: /* first step is to make up a grave dentry in the graveyard */ - sprintf(nbuffer, "%08x%08x", - (uint32_t) get_seconds(), + sprintf(nbuffer, "%08llx%08x", + (uint64_t) ktime_get_real_seconds(), (uint32_t) atomic_inc_return(&cache->gravecounter)); /* do the multiway lock magic */ -- 2.9.0