From patchwork Thu Mar 10 19:18:51 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kara X-Patchwork-Id: 8559601 Return-Path: X-Original-To: patchwork-linux-nvdimm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 2DBD9C0553 for ; Thu, 10 Mar 2016 19:18:44 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 6203720381 for ; Thu, 10 Mar 2016 19:18:43 +0000 (UTC) Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8F4E52037E for ; Thu, 10 Mar 2016 19:18:42 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 79CD01A1F5B; Thu, 10 Mar 2016 11:18:57 -0800 (PST) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 3EF061A1F51 for ; Thu, 10 Mar 2016 11:18:54 -0800 (PST) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 484F0ACB0; Thu, 10 Mar 2016 19:18:36 +0000 (UTC) Received: by quack.suse.cz (Postfix, from userid 1000) id 3CF1882526; Thu, 10 Mar 2016 20:18:57 +0100 (CET) From: Jan Kara To: linux-fsdevel@vger.kernel.org Subject: [PATCH 08/12] dax: Fix bogus fault return value on cow faults Date: Thu, 10 Mar 2016 20:18:51 +0100 Message-Id: <1457637535-21633-9-git-send-email-jack@suse.cz> X-Mailer: git-send-email 2.6.2 In-Reply-To: <1457637535-21633-1-git-send-email-jack@suse.cz> References: <1457637535-21633-1-git-send-email-jack@suse.cz> Cc: Jan Kara , linux-nvdimm@lists.01.org, NeilBrown , "Wilcox, Matthew R" X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP In case of cow fault when there is no page mapped at cow location, we return VM_FAULT_LOCKED despite we don't return any page from the fault. The code in do_cow_fault() carefully handled the case when no page was actually returned so no harm was done but still this is a bug waiting to happen. Signed-off-by: Jan Kara --- fs/dax.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/dax.c b/fs/dax.c index 4aa440f9305b..bf39f16e5390 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -680,7 +680,9 @@ int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, if (error) goto unlock_page; vmf->page = page; - return VM_FAULT_LOCKED; + if (page) + return VM_FAULT_LOCKED; + return 0; } /* Check we didn't race with a read fault installing a new page */