may_follow_link() should use nd->inode

Al Viro · Al Viro · commit aa65fa35ba6b · 2015-08-04T23:23:50.000-04:00
Now that we can get there in RCU mode, we shouldn't play with
nd-&gt;path.dentry-&gt;d_inode - it's not guaranteed to be stable.
Use nd-&gt;inode instead.

Reported-by: Hugh Dickins &lt;hughd@google.com&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
diff --git a/fs/namei.c b/fs/namei.c
@@ -879,7 +879,7 @@ static inline int may_follow_link(struct nameidata *nd)
 		return 0;
 
 	/* Allowed if parent directory not sticky and world-writable. */
-	parent = nd->path.dentry->d_inode;
+	parent = nd->inode;
 	if ((parent->i_mode & (S_ISVTX|S_IWOTH)) != (S_ISVTX|S_IWOTH))
 		return 0;
 
