[PATCH 1/3] fs: move path_put on failure out of ->follow_link

[Christoph Hellwig <hch@infradead.org>]

[-- Attachment #1: fs-follow_link-dont-put --]
[-- Type: text/plain, Size: 2010 bytes --]

Currently the non-nd_set_link based versions of ->follow_link are expected
to do a path_put(&nd->path).  This calling convention is unexpected,
undocumented and doesn't match what the nd_set_link-based instance do.

Move the path_put out of the only non-nd_set_link based ->follow_link
instance into the caller.

Signed-off-by: Christoph Hellwig <hch@lst.de>

---
 fs/namei.c     |    3 +--
 fs/proc/base.c |   12 ++++++++----
 2 files changed, 9 insertions(+), 6 deletions(-)

Index: linux-2.6/fs/namei.c
===================================================================
--- linux-2.6.orig/fs/namei.c	2012-06-18 12:46:47.560143542 +0200
+++ linux-2.6/fs/namei.c	2012-06-18 12:47:02.424143920 +0200
@@ -615,7 +615,7 @@ follow_link(struct path *link, struct na
 	*p = dentry->d_inode->i_op->follow_link(dentry, nd);
 	error = PTR_ERR(*p);
 	if (IS_ERR(*p))
-		goto out_put_link;
+		goto out_put_nd_path;
 
 	error = 0;
 	s = nd_get_link(nd);
@@ -640,7 +640,6 @@ follow_link(struct path *link, struct na
 
 out_put_nd_path:
 	path_put(&nd->path);
-out_put_link:
 	path_put(link);
 	return error;
 }
Index: linux-2.6/fs/proc/base.c
===================================================================
--- linux-2.6.orig/fs/proc/base.c	2012-06-18 12:46:47.560143542 +0200
+++ linux-2.6/fs/proc/base.c	2012-06-18 12:47:02.424143920 +0200
@@ -1427,16 +1427,20 @@ static int proc_exe_link(struct dentry *
 static void *proc_pid_follow_link(struct dentry *dentry, struct nameidata *nd)
 {
 	struct inode *inode = dentry->d_inode;
+	struct path path;
 	int error = -EACCES;
 
-	/* We don't need a base pointer in the /proc filesystem */
-	path_put(&nd->path);
-
 	/* Are we allowed to snoop on the tasks file descriptors? */
 	if (!proc_fd_access_allowed(inode))
 		goto out;
 
-	error = PROC_I(inode)->op.proc_get_link(dentry, &nd->path);
+	error = PROC_I(inode)->op.proc_get_link(dentry, &path);
+	if (error)
+		goto out;
+
+	path_put(&nd->path);
+	nd->path = path;
+	return NULL;
 out:
 	return ERR_PTR(error);
 }