From patchwork Mon May 11 18:07:52 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Al Viro X-Patchwork-Id: 6380721 Return-Path: X-Original-To: patchwork-linux-fsdevel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 140D29F32B for ; Mon, 11 May 2015 18:14:09 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 33B38209CD for ; Mon, 11 May 2015 18:14:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 33845209DA for ; Mon, 11 May 2015 18:14:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932543AbbEKSOE (ORCPT ); Mon, 11 May 2015 14:14:04 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:47515 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755037AbbEKSI3 (ORCPT ); Mon, 11 May 2015 14:08:29 -0400 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.76 #1 (Red Hat Linux)) id 1Yrs7u-0001Vb-P9; Mon, 11 May 2015 18:08:26 +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 092/110] namei: explicitly pass seq number to unlazy_walk() when dentry != NULL Date: Mon, 11 May 2015 19:07:52 +0100 Message-Id: <1431367690-5223-92-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 | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index 756e150..97315df 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -567,13 +567,14 @@ static inline int nd_alloc_stack(struct nameidata *nd) * unlazy_walk - try to switch to ref-walk mode. * @nd: nameidata pathwalk data * @dentry: child of nd->path.dentry or NULL + * @seq: seq number to check dentry against * Returns: 0 on success, -ECHILD on failure * * unlazy_walk attempts to legitimize the current nd->path, nd->root and dentry * for ref-walk mode. @dentry must be a path found by a do_lookup call on * @nd or NULL. Must be called from rcu-walk context. */ -static int unlazy_walk(struct nameidata *nd, struct dentry *dentry) +static int unlazy_walk(struct nameidata *nd, struct dentry *dentry, unsigned seq) { struct fs_struct *fs = current->fs; struct dentry *parent = nd->path.dentry; @@ -615,7 +616,7 @@ static int unlazy_walk(struct nameidata *nd, struct dentry *dentry) } else { if (!lockref_get_not_dead(&dentry->d_lockref)) goto out; - if (read_seqcount_retry(&dentry->d_seq, nd->seq)) + if (read_seqcount_retry(&dentry->d_seq, seq)) goto drop_dentry; } @@ -671,7 +672,7 @@ static int complete_walk(struct nameidata *nd) if (nd->flags & LOOKUP_RCU) { if (!(nd->flags & LOOKUP_ROOT)) nd->root.mnt = NULL; - if (unlikely(unlazy_walk(nd, NULL))) + if (unlikely(unlazy_walk(nd, NULL, 0))) return -ECHILD; } @@ -1451,7 +1452,7 @@ static int lookup_fast(struct nameidata *nd, if (likely(__follow_mount_rcu(nd, path, inode))) return 0; unlazy: - if (unlazy_walk(nd, dentry)) + if (unlazy_walk(nd, dentry, nd->seq)) return -ECHILD; } else { dentry = __d_lookup(parent, &nd->last); @@ -1511,7 +1512,7 @@ static inline int may_lookup(struct nameidata *nd) int err = inode_permission(nd->inode, MAY_EXEC|MAY_NOT_BLOCK); if (err != -ECHILD) return err; - if (unlazy_walk(nd, NULL)) + if (unlazy_walk(nd, NULL, 0)) return -ECHILD; } return inode_permission(nd->inode, MAY_EXEC); @@ -1552,7 +1553,7 @@ static int pick_link(struct nameidata *nd, struct path *link) } if (nd->flags & LOOKUP_RCU) { if (unlikely(nd->path.mnt != link->mnt || - unlazy_walk(nd, link->dentry))) { + unlazy_walk(nd, link->dentry, nd->seq))) { return -ECHILD; } } @@ -2297,7 +2298,7 @@ mountpoint_last(struct nameidata *nd, struct path *path) /* If we're in rcuwalk, drop out of it to handle last component */ if (nd->flags & LOOKUP_RCU) { - if (unlazy_walk(nd, NULL)) + if (unlazy_walk(nd, NULL, 0)) return -ECHILD; }