1 files changed, 33 insertions, 0 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index 9f544f35ed34..bec51e4e0549 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1895,6 +1895,39 @@ static int do_new_mount(struct path *path, char *type, int flags,
         return do_add_mount(mnt, path, mnt_flags);
 }
 
+int finish_automount(struct vfsmount *m, struct path *path)
+{
+        int err;
+        /* The new mount record should have at least 2 refs to prevent it being
+         * expired before we get a chance to add it
+         */
+        BUG_ON(mnt_get_count(m) < 2);
+
+        if (m->mnt_sb == path->mnt->mnt_sb &&
+            m->mnt_root == path->dentry) {
+                mnt_clear_expiry(m);
+                mntput(m);
+                mntput(m);
+                return -ELOOP;
+        }
+
+        /* We need to add the mountpoint to the parent.  The filesystem may
+         * have placed it on an expiry list, and so we need to make sure it
+         * won't be expired under us if do_add_mount() fails (do_add_mount()
+         * will eat a reference unconditionally).
+         */
+        mntget(m);
+        err = do_add_mount(m, path, path->mnt->mnt_flags | MNT_SHRINKABLE);
+        if (err) {
+                mnt_clear_expiry(m);
+                mntput(m);
+                mntput(m);
+        } else {
+                mntput(m);
+        }
+        return err;
+}
+
 /*
  * add a mount into a namespace's mount tree
  * - this unconditionally eats one of the caller's references to newmnt.