+/**
+ * path_connected - Verify that a path->dentry is below path->mnt.mnt_root
+ * @path: nameidate to verify
+ *
+ * Rename can sometimes move a file or directory outside of a bind
+ * mount, path_connected allows those cases to be detected.
+ */
+static bool path_connected(const struct path *path)
+{
+ struct vfsmount *mnt = path->mnt;
+ struct super_block *sb = mnt->mnt_sb;
+
+ /* Bind mounts and multi-root filesystems can have disconnected paths */
+ if (!(sb->s_iflags & SB_I_MULTIROOT) && (mnt->mnt_root == sb->s_root))
+ return true;
+
+ return is_subdir(path->dentry, mnt->mnt_root);
+}
+