1 files changed, 42 insertions, 7 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 4c4f95ac8aa5..6a82fb7e2127 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1416,21 +1416,28 @@ static void follow_mount(struct path *path)
         }
 }
 
+static int path_parent_directory(struct path *path)
+{
+        struct dentry *old = path->dentry;
+        /* rare case of legitimate dget_parent()... */
+        path->dentry = dget_parent(path->dentry);
+        dput(old);
+        if (unlikely(!path_connected(path)))
+                return -ENOENT;
+        return 0;
+}
+
 static int follow_dotdot(struct nameidata *nd)
 {
         while(1) {
-                struct dentry *old = nd->path.dentry;
-
                 if (nd->path.dentry == nd->root.dentry &&
                     nd->path.mnt == nd->root.mnt) {
                         break;
                 }
                 if (nd->path.dentry != nd->path.mnt->mnt_root) {
-                        /* rare case of legitimate dget_parent()... */
-                        nd->path.dentry = dget_parent(nd->path.dentry);
-                        dput(old);
-                        if (unlikely(!path_connected(&nd->path)))
-                                return -ENOENT;
+                        int ret = path_parent_directory(&nd->path);
+                        if (ret)
+                                return ret;
                         break;
                 }
                 if (!follow_up(&nd->path))
@@ -2514,6 +2521,34 @@ struct dentry *lookup_one_len_unlocked(const char *name,
 }
 EXPORT_SYMBOL(lookup_one_len_unlocked);
 
+#ifdef CONFIG_UNIX98_PTYS
+int path_pts(struct path *path)
+{
+        /* Find something mounted on "pts" in the same directory as
+         * the input path.
+         */
+        struct dentry *child, *parent;
+        struct qstr this;
+        int ret;
+
+        ret = path_parent_directory(path);
+        if (ret)
+                return ret;
+
+        parent = path->dentry;
+        this.name = "pts";
+        this.len = 3;
+        child = d_hash_and_lookup(parent, &this);
+        if (!child)
+                return -ENOENT;
+
+        path->dentry = child;
+        dput(parent);
+        follow_mount(path);
+        return 0;
+}
+#endif
+
 int user_path_at_empty(int dfd, const char __user *name, unsigned flags,
                  struct path *path, int *empty)
 {