From patchwork Mon Mar 16 04:43:20 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: NeilBrown X-Patchwork-Id: 6015311 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 58B53BF90F for ; Mon, 16 Mar 2015 04:47:08 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 898FB203E3 for ; Mon, 16 Mar 2015 04:47:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 97C7A203DA for ; Mon, 16 Mar 2015 04:47:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752755AbbCPEon (ORCPT ); Mon, 16 Mar 2015 00:44:43 -0400 Received: from cantor2.suse.de ([195.135.220.15]:56203 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750736AbbCPEol (ORCPT ); Mon, 16 Mar 2015 00:44:41 -0400 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 5AC68AAF3; Mon, 16 Mar 2015 04:44:39 +0000 (UTC) From: NeilBrown To: Al Viro Date: Mon, 16 Mar 2015 15:43:20 +1100 Subject: [PATCH 05/13] VFS/namei: use terminate_walk when symlink lookup fails. Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Message-ID: <20150316044319.23648.34965.stgit@notabene.brown> In-Reply-To: <20150316043602.23648.52734.stgit@notabene.brown> References: <20150316043602.23648.52734.stgit@notabene.brown> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 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 Currently following a symlink never uses rcu-walk, so terminate_walk isn't needed. That will change in a future patch. In preparation, change some path_put_condtional() path_put() sequences to path_to_nameidata() terminate_walk() These sequence are identical when in ref-walk, and correct when in rcu-walk. Also change two path_put() calls to equivalent terminate_walk(). Signed-off-by: NeilBrown --- fs/namei.c | 40 ++++++++++++++++++++-------------------- 1 file changed, 20 insertions(+), 20 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/fs/namei.c b/fs/namei.c index 9a5d429f2a8a..8cb89a0d30ba 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -749,6 +749,18 @@ char *nd_get_link(void) } EXPORT_SYMBOL(nd_get_link); +static void terminate_walk(struct nameidata *nd) +{ + if (!(nd->flags & LOOKUP_RCU)) { + path_put(&nd->path); + } else { + nd->flags &= ~LOOKUP_RCU; + if (!(nd->flags & LOOKUP_ROOT)) + nd->root.mnt = NULL; + rcu_read_unlock(); + } +} + static inline void put_link(struct nameidata *nd, struct path *link, void *cookie) { struct inode *inode = link->dentry->d_inode; @@ -799,8 +811,8 @@ static inline int may_follow_link(struct path *link, struct nameidata *nd) return 0; audit_log_link_denied("follow_link", link); - path_put_conditional(link, nd); - path_put(&nd->path); + path_to_nameidata(link, nd); + terminate_walk(nd); return -EACCES; } @@ -909,7 +921,7 @@ follow_link(struct path *link, struct nameidata *nd, void **p) s = nd_get_link(); if (s) { if (unlikely(IS_ERR(s))) { - path_put(&nd->path); + terminate_walk(nd); put_link(nd, link, *p); return PTR_ERR(s); } @@ -931,7 +943,7 @@ follow_link(struct path *link, struct nameidata *nd, void **p) out_put_nd_path: *p = NULL; - path_put(&nd->path); + terminate_walk(nd); path_put(link); return error; } @@ -1562,18 +1574,6 @@ static inline int handle_dots(struct nameidata *nd, int type) return 0; } -static void terminate_walk(struct nameidata *nd) -{ - if (!(nd->flags & LOOKUP_RCU)) { - path_put(&nd->path); - } else { - nd->flags &= ~LOOKUP_RCU; - if (!(nd->flags & LOOKUP_ROOT)) - nd->root.mnt = NULL; - rcu_read_unlock(); - } -} - /* * Do we need to follow links? We _really_ want to be able * to do this check without having to look at inode->i_op, @@ -1645,8 +1645,8 @@ static inline int nested_symlink(struct path *path, struct nameidata *nd) int res; if (unlikely(current->nameidata->link_count >= MAX_NESTED_LINKS)) { - path_put_conditional(path, nd); - path_put(&nd->path); + path_to_nameidata(path, nd); + terminate_walk(nd); return -ELOOP; } BUG_ON(nd->depth >= MAX_NESTED_LINKS); @@ -3267,8 +3267,8 @@ static struct file *path_openat(int dfd, struct filename *pathname, struct path link = path; void *cookie; if (!(nd->flags & LOOKUP_FOLLOW)) { - path_put_conditional(&path, nd); - path_put(&nd->path); + path_to_nameidata(&path, nd); + terminate_walk(nd); error = -ELOOP; break; }