linux-kernel - [PATCH v3 084/110] namei: take increment of nd->depth into pick

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Message-Id: <1431367690-5223-84-git-send-email-viro@ZenIV.linux.org.uk>
Date:	Mon, 11 May 2015 19:07:44 +0100
From:	Al Viro <viro@...IV.linux.org.uk>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Neil Brown <neilb@...e.de>, Christoph Hellwig <hch@...radead.org>,
	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: [PATCH v3 084/110] namei: take increment of nd->depth into pick_link()

From: Al Viro <viro@...iv.linux.org.uk>

Makes the situation much more regular - we avoid a strange state
when the element just after the top of stack is used to store
struct path of symlink, but isn't counted in nd->depth.  This
is much more regular, so the normal failure exits, etc., work
fine.

Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
 fs/namei.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 277ca86..6d4692d 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -798,8 +798,7 @@ static inline int may_follow_link(struct nameidata *nd)
 		return 0;
 
 	audit_log_link_denied("follow_link", &nd->stack[0].link);
-	path_put(&nd->stack[0].link);
-	path_put(&nd->path);
+	terminate_walk(nd);
 	return -EACCES;
 }
 
@@ -875,7 +874,7 @@ static int may_linkat(struct path *link)
 static __always_inline
 const char *get_link(struct nameidata *nd)
 {
-	struct saved *last = nd->stack + nd->depth;
+	struct saved *last = nd->stack + nd->depth - 1;
 	struct dentry *dentry = last->link.dentry;
 	struct inode *inode = dentry->d_inode;
 	int error;
@@ -883,9 +882,6 @@ const char *get_link(struct nameidata *nd)
 
 	BUG_ON(nd->flags & LOOKUP_RCU);
 
-	last->cookie = NULL;
-	nd->depth++;
-
 	cond_resched();
 
 	touch_atime(&last->link);
@@ -1575,8 +1571,9 @@ static int pick_link(struct nameidata *nd, struct path *link)
 		return error;
 	}
 
-	last = nd->stack + nd->depth;
+	last = nd->stack + nd->depth++;
 	last->link = *link;
+	last->cookie = NULL;
 	return 1;
 }
 
-- 
2.1.4

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