From patchwork Mon May 11 18:08:01 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Al Viro X-Patchwork-Id: 6380651 Return-Path: X-Original-To: patchwork-linux-fsdevel@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 D2C19BEEE5 for ; Mon, 11 May 2015 18:13:41 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 18E0B209CD for ; Mon, 11 May 2015 18:13:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2D4CB209D7 for ; Mon, 11 May 2015 18:13:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932446AbbEKSMO (ORCPT ); Mon, 11 May 2015 14:12:14 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:47584 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755059AbbEKSIa (ORCPT ); Mon, 11 May 2015 14:08:30 -0400 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.76 #1 (Red Hat Linux)) id 1Yrs7w-0001WT-Cr; Mon, 11 May 2015 18:08:28 +0000 From: Al Viro To: Linus Torvalds Cc: Neil Brown , Christoph Hellwig , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH v3 101/110] namei: make put_link() RCU-safe Date: Mon, 11 May 2015 19:08:01 +0100 Message-Id: <1431367690-5223-101-git-send-email-viro@ZenIV.linux.org.uk> X-Mailer: git-send-email 1.7.7.6 In-Reply-To: <20150511180650.GA4147@ZenIV.linux.org.uk> References: <20150511180650.GA4147@ZenIV.linux.org.uk> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_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 From: Al Viro very simple - just make path_put() conditional on !RCU. Note that right now it doesn't get called in RCU mode - we leave it before getting anything into stack. Signed-off-by: Al Viro --- fs/namei.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/namei.c b/fs/namei.c index 4303404..998c3c2 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -750,7 +750,8 @@ static inline void put_link(struct nameidata *nd) struct inode *inode = last->inode; if (last->cookie && inode->i_op->put_link) inode->i_op->put_link(inode, last->cookie); - path_put(&last->link); + if (!(nd->flags & LOOKUP_RCU)) + path_put(&last->link); } int sysctl_protected_symlinks __read_mostly = 0;