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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 3E863C43441 for ; Fri, 16 Nov 2018 07:55:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0308A208E7 for ; Fri, 16 Nov 2018 07:55:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0308A208E7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=virtuozzo.com 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 S2389308AbeKPSHI (ORCPT ); Fri, 16 Nov 2018 13:07:08 -0500 Received: from relay.sw.ru ([185.231.240.75]:53012 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727410AbeKPSHH (ORCPT ); Fri, 16 Nov 2018 13:07:07 -0500 Received: from [172.16.24.21] by relay.sw.ru with esmtp (Exim 4.90_1) (envelope-from ) id 1gNYyg-0004Z1-8L; Fri, 16 Nov 2018 10:55:46 +0300 Subject: Re: [PATCH] mm: cleancache: fix corruption on missed inode invalidation To: Andrew Morton , Pavel Tikhomirov Cc: Andrey Ryabinin , Konstantin Khorenko , Johannes Weiner , Mel Gorman , Jan Kara , Matthew Wilcox , Andi Kleen , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20181112095734.17979-1-ptikhomirov@virtuozzo.com> <20181115143103.c6fa8fec343bb706b91f6c6c@linux-foundation.org> From: Vasily Averin Message-ID: Date: Fri, 16 Nov 2018 10:55:45 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20181115143103.c6fa8fec343bb706b91f6c6c@linux-foundation.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/16/18 1:31 AM, Andrew Morton wrote: > On Mon, 12 Nov 2018 12:57:34 +0300 Pavel Tikhomirov wrote: > >> If all pages are deleted from the mapping by memory reclaim and also >> moved to the cleancache: >> >> __delete_from_page_cache >> (no shadow case) >> unaccount_page_cache_page >> cleancache_put_page >> page_cache_delete >> mapping->nrpages -= nr >> (nrpages becomes 0) >> >> We don't clean the cleancache for an inode after final file truncation >> (removal). >> >> truncate_inode_pages_final >> check (nrpages || nrexceptional) is false >> no truncate_inode_pages >> no cleancache_invalidate_inode(mapping) >> >> These way when reading the new file created with same inode we may get >> these trash leftover pages from cleancache and see wrong data instead of >> the contents of the new file. >> >> Fix it by always doing truncate_inode_pages which is already ready for >> nrpages == 0 && nrexceptional == 0 case and just invalidates inode. >> > > Data corruption sounds serious. Shouldn't we backport this into > -stable kernels? Yes, it was broken in 4.14 kernel and it should affect all who uses cleancache Fixes: commit 91b0abe36a7b ("mm + fs: store shadow entries in page cache")