From patchwork Sun Jan 19 03:17:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Al Viro X-Patchwork-Id: 11340509 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 95322921 for ; Sun, 19 Jan 2020 03:26:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 73A572051A for ; Sun, 19 Jan 2020 03:26:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726635AbgASDZ5 (ORCPT ); Sat, 18 Jan 2020 22:25:57 -0500 Received: from zeniv.linux.org.uk ([195.92.253.2]:57016 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725497AbgASDZ5 (ORCPT ); Sat, 18 Jan 2020 22:25:57 -0500 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1it1DO-00BFlc-6j; Sun, 19 Jan 2020 03:25:36 +0000 From: Al Viro To: linux-fsdevel@vger.kernel.org Cc: Linus Torvalds , linux-kernel@vger.kernel.org, Aleksa Sarai , David Howells , Eric Biederman , Christian Brauner , Al Viro Subject: [PATCH 7/9] finally fold get_link() into pick_link() Date: Sun, 19 Jan 2020 03:17:36 +0000 Message-Id: <20200119031738.2681033-24-viro@ZenIV.linux.org.uk> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200119031738.2681033-1-viro@ZenIV.linux.org.uk> References: <20200119031423.GV8904@ZenIV.linux.org.uk> <20200119031738.2681033-1-viro@ZenIV.linux.org.uk> MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Al Viro kill nd->link_inode, while we are at it Signed-off-by: Al Viro --- fs/namei.c | 135 ++++++++++++++++++++++++----------------------------- 1 file changed, 61 insertions(+), 74 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index adb573e0f424..40263f89a54f 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -503,7 +503,6 @@ struct nameidata { } *stack, internal[EMBEDDED_LEVELS]; struct filename *name; struct nameidata *saved; - struct inode *link_inode; unsigned root_seq; int dfd; } __randomize_layout; @@ -962,9 +961,8 @@ int sysctl_protected_regular __read_mostly; * * Returns 0 if following the symlink is allowed, -ve on error. */ -static inline int may_follow_link(struct nameidata *nd) +static inline int may_follow_link(struct nameidata *nd, const struct inode *inode) { - const struct inode *inode; const struct inode *parent; kuid_t puid; @@ -972,7 +970,6 @@ static inline int may_follow_link(struct nameidata *nd) return 0; /* Allowed if owner and follower match. */ - inode = nd->link_inode; if (uid_eq(current_cred()->fsuid, inode->i_uid)) return 0; @@ -1105,73 +1102,6 @@ static int may_create_in_sticky(struct dentry * const dir, return 0; } -static __always_inline -const char *get_link(struct nameidata *nd) -{ - struct saved *last = nd->stack + nd->depth - 1; - struct dentry *dentry = last->link.dentry; - struct inode *inode = nd->link_inode; - int error; - const char *res; - - if (!(nd->flags & LOOKUP_PARENT)) { - error = may_follow_link(nd); - if (unlikely(error)) - return ERR_PTR(error); - } - - if (unlikely(nd->flags & LOOKUP_NO_SYMLINKS)) - return ERR_PTR(-ELOOP); - - if (!(nd->flags & LOOKUP_RCU)) { - touch_atime(&last->link); - cond_resched(); - } else if (atime_needs_update(&last->link, inode)) { - if (unlikely(unlazy_walk(nd))) - return ERR_PTR(-ECHILD); - touch_atime(&last->link); - } - - error = security_inode_follow_link(dentry, inode, - nd->flags & LOOKUP_RCU); - if (unlikely(error)) - return ERR_PTR(error); - - nd->last_type = LAST_BIND; - res = READ_ONCE(inode->i_link); - if (!res) { - const char * (*get)(struct dentry *, struct inode *, - struct delayed_call *); - get = inode->i_op->get_link; - if (nd->flags & LOOKUP_RCU) { - res = get(NULL, inode, &last->done); - if (res == ERR_PTR(-ECHILD)) { - if (unlikely(unlazy_walk(nd))) - return ERR_PTR(-ECHILD); - res = get(dentry, inode, &last->done); - } - } else { - res = get(dentry, inode, &last->done); - } - if (!res) - goto all_done; - if (IS_ERR(res)) - return res; - } - if (*res == '/') { - error = nd_jump_root(nd); - if (unlikely(error)) - return ERR_PTR(error); - while (unlikely(*++res == '/')) - ; - } - if (*res) - return res; -all_done: // pure jump - put_link(nd); - return NULL; -} - /* * follow_up - Find the mountpoint of path's vfsmount * @@ -1795,8 +1725,10 @@ static inline int handle_dots(struct nameidata *nd, int type) static const char *pick_link(struct nameidata *nd, struct path *link, struct inode *inode, unsigned seq) { - int error; struct saved *last; + const char *res; + int error; + if (unlikely(nd->total_link_count++ >= MAXSYMLINKS)) { path_to_nameidata(link, nd); return ERR_PTR(-ELOOP); @@ -1827,9 +1759,64 @@ static const char *pick_link(struct nameidata *nd, struct path *link, last = nd->stack + nd->depth++; last->link = *link; clear_delayed_call(&last->done); - nd->link_inode = inode; last->seq = seq; - return get_link(nd); + + if (!(nd->flags & LOOKUP_PARENT)) { + error = may_follow_link(nd, inode); + if (unlikely(error)) + return ERR_PTR(error); + } + + if (unlikely(nd->flags & LOOKUP_NO_SYMLINKS)) + return ERR_PTR(-ELOOP); + + if (!(nd->flags & LOOKUP_RCU)) { + touch_atime(&last->link); + cond_resched(); + } else if (atime_needs_update(&last->link, inode)) { + if (unlikely(unlazy_walk(nd))) + return ERR_PTR(-ECHILD); + touch_atime(&last->link); + } + + error = security_inode_follow_link(link->dentry, inode, + nd->flags & LOOKUP_RCU); + if (unlikely(error)) + return ERR_PTR(error); + + nd->last_type = LAST_BIND; + res = READ_ONCE(inode->i_link); + if (!res) { + const char * (*get)(struct dentry *, struct inode *, + struct delayed_call *); + get = inode->i_op->get_link; + if (nd->flags & LOOKUP_RCU) { + res = get(NULL, inode, &last->done); + if (res == ERR_PTR(-ECHILD)) { + if (unlikely(unlazy_walk(nd))) + return ERR_PTR(-ECHILD); + res = get(link->dentry, inode, &last->done); + } + } else { + res = get(link->dentry, inode, &last->done); + } + if (!res) + goto all_done; + if (IS_ERR(res)) + return res; + } + if (*res == '/') { + error = nd_jump_root(nd); + if (unlikely(error)) + return ERR_PTR(error); + while (unlikely(*++res == '/')) + ; + } + if (*res) + return res; +all_done: // pure jump + put_link(nd); + return NULL; } enum {WALK_FOLLOW = 1, WALK_MORE = 2, WALK_NOFOLLOW = 4};