From patchwork Mon May 11 18:08:06 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Al Viro X-Patchwork-Id: 6380511 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 6B7A3BEEE1 for ; Mon, 11 May 2015 18:11:58 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 9B3D1209C3 for ; Mon, 11 May 2015 18:11:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9AFA4209C2 for ; Mon, 11 May 2015 18:11:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755187AbbEKSK7 (ORCPT ); Mon, 11 May 2015 14:10:59 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:47623 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755071AbbEKSIb (ORCPT ); Mon, 11 May 2015 14:08:31 -0400 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.76 #1 (Red Hat Linux)) id 1Yrs7x-0001X0-Do; Mon, 11 May 2015 18:08:29 +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 106/110] namei: don't unlazy until get_link() Date: Mon, 11 May 2015 19:08:06 +0100 Message-Id: <1431367690-5223-106-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 Signed-off-by: Al Viro --- fs/namei.c | 37 ++++++++++++++++++++++++++----------- 1 file changed, 26 insertions(+), 11 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index 090214b..4d6065d 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -536,10 +536,19 @@ static void restore_nameidata(struct nameidata *old) static int __nd_alloc_stack(struct nameidata *nd) { - struct saved *p = kmalloc(MAXSYMLINKS * sizeof(struct saved), + struct saved *p; + + if (nd->flags & LOOKUP_RCU) { + p= kmalloc(MAXSYMLINKS * sizeof(struct saved), + GFP_ATOMIC); + if (unlikely(!p)) + return -ECHILD; + } else { + p= kmalloc(MAXSYMLINKS * sizeof(struct saved), GFP_KERNEL); - if (unlikely(!p)) - return -ENOMEM; + if (unlikely(!p)) + return -ENOMEM; + } memcpy(p, nd->internal, sizeof(nd->internal)); nd->stack = p; return 0; @@ -949,8 +958,10 @@ const char *get_link(struct nameidata *nd) int error; const char *res; - BUG_ON(nd->flags & LOOKUP_RCU); - + if (nd->flags & LOOKUP_RCU) { + if (unlikely(unlazy_walk(nd, NULL, 0))) + return ERR_PTR(-ECHILD); + } cond_resched(); touch_atime(&last->link); @@ -1632,17 +1643,21 @@ static int pick_link(struct nameidata *nd, struct path *link, path_to_nameidata(link, nd); return -ELOOP; } - if (nd->flags & LOOKUP_RCU) { - if (unlikely(unlazy_link(nd, link, seq))) - return -ECHILD; - } else { + if (!(nd->flags & LOOKUP_RCU)) { if (link->mnt == nd->path.mnt) mntget(link->mnt); } error = nd_alloc_stack(nd); if (unlikely(error)) { - path_put(link); - return error; + if (error == -ECHILD) { + if (unlikely(unlazy_link(nd, link, seq))) + return -ECHILD; + error = nd_alloc_stack(nd); + } + if (error) { + path_put(link); + return error; + } } last = nd->stack + nd->depth++;