[001/145] fix LOOKUP_FOLLOW on automount "symlinks"

From: Greg KH
Date: Fri Mar 12 2010 - 20:15:00 EST


2.6.32-stable review patch. If anyone has any objections, please let me know.

----------------
From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

commit ac278a9c505092dd82077a2446af8f9fc0d9c095 upstream.

Make sure that automount "symlinks" are followed regardless of LOOKUP_FOLLOW;
it should have no effect on them.

Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
fs/namei.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)

--- a/fs/namei.c
+++ b/fs/namei.c
@@ -829,6 +829,17 @@ fail:
}

/*
+ * This is a temporary kludge to deal with "automount" symlinks; proper
+ * solution is to trigger them on follow_mount(), so that do_lookup()
+ * would DTRT. To be killed before 2.6.34-final.
+ */
+static inline int follow_on_final(struct inode *inode, unsigned lookup_flags)
+{
+ return inode && unlikely(inode->i_op->follow_link) &&
+ ((lookup_flags & LOOKUP_FOLLOW) || S_ISDIR(inode->i_mode));
+}
+
+/*
* Name resolution.
* This is the basic name resolution function, turning a pathname into
* the final dentry. We expect 'base' to be positive and a directory.
@@ -964,8 +975,7 @@ last_component:
if (err)
break;
inode = next.dentry->d_inode;
- if ((lookup_flags & LOOKUP_FOLLOW)
- && inode && inode->i_op->follow_link) {
+ if (follow_on_final(inode, lookup_flags)) {
err = do_follow_link(&next, nd);
if (err)
goto return_err;


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