Title: Use of index and the "racy git" problem
Author: Junio C Hamano
Abstract: In order to speed up comparison between files in
the work tree and index entries, git compares current
lstat(2) information with saved lstat(2) information from
whenever it updated the corresponding index entry. A very
quick update that does not change file size could therefore
make git incorrectly think files in the working tree are
unmodified even though they actually are modified. This is
called the "racy git" problem (discovered by Pasky), and
the entries that would appear clean when they ought not to
be because of this problem are called "racily clean".
This document explains how git avoids that problem.
Section: File Management