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[209.132.180.67]) by mx.google.com with ESMTP id c4si2309718pll.412.2018.11.12.03.32.18; Mon, 12 Nov 2018 03:32:34 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729166AbeKLVYr (ORCPT + 99 others); Mon, 12 Nov 2018 16:24:47 -0500 Received: from mx2.suse.de ([195.135.220.15]:56630 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728153AbeKLVYr (ORCPT ); Mon, 12 Nov 2018 16:24:47 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 2D70AB074; Mon, 12 Nov 2018 11:31:55 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 53C2B1E09A5; Mon, 12 Nov 2018 12:31:53 +0100 (CET) Date: Mon, 12 Nov 2018 12:31:53 +0100 From: Jan Kara To: Pavel Tikhomirov Cc: Andrew Morton , Vasily Averin , Andrey Ryabinin , Konstantin Khorenko , Johannes Weiner , Mel Gorman , Jan Kara , Matthew Wilcox , Andi Kleen , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: cleancache: fix corruption on missed inode invalidation Message-ID: <20181112113153.GC7175@quack2.suse.cz> References: <20181112095734.17979-1-ptikhomirov@virtuozzo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181112095734.17979-1-ptikhomirov@virtuozzo.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 12-11-18 12:57:34, 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. > > Fixes: commit 91b0abe36a7b ("mm + fs: store shadow entries in page cache") > To: Andrew Morton > Cc: Johannes Weiner > Cc: Mel Gorman > Cc: Jan Kara > Cc: Matthew Wilcox > Cc: Andi Kleen > Cc: linux-mm@kvack.org > Cc: linux-kernel@vger.kernel.org > Reviewed-by: Vasily Averin > Reviewed-by: Andrey Ryabinin > Signed-off-by: Pavel Tikhomirov > --- > mm/truncate.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) The patch looks good but can you add a short comment before the truncate_inode_pages() call explaining why it needs to be called always? Something like: /* * Cleancache needs notification even if there are no pages or * shadow entries... */ Otherwise you can add: Reviewed-by: Jan Kara Honza > > diff --git a/mm/truncate.c b/mm/truncate.c > index 45d68e90b703..4c56c19e76eb 100644 > --- a/mm/truncate.c > +++ b/mm/truncate.c > @@ -517,9 +517,9 @@ void truncate_inode_pages_final(struct address_space *mapping) > */ > xa_lock_irq(&mapping->i_pages); > xa_unlock_irq(&mapping->i_pages); > - > - truncate_inode_pages(mapping, 0); > } > + > + truncate_inode_pages(mapping, 0); > } > EXPORT_SYMBOL(truncate_inode_pages_final); > > -- > 2.17.1 > -- Jan Kara SUSE Labs, CR