- /* The device, inode number and ctime of the placeholder. Use
- ctime, not mtime, to make false matches less likely if some
- other process removes the placeholder. */
+ /* The device, inode number and birthtime of the placeholder.
+ birthtime.tv_nsec is negative if the birthtime is not available.
+ Don't use mtime as this would allow for false matches if some
+ other process removes the placeholder. Don't use ctime as
+ this would cause race conditions and other screwups, e.g.,
+ when restoring hard-linked symlinks. */