Subject: [PATCH 9/9] racy-git.txt: explain nsec problem in more detail

From: Jonathan Nieder <[email-masked]>
Date: Fri, 9 Oct 2009 05:25:54 -0500

Idealists may want USE_NSEC to be the default on Linux some day.
Point to a patch to better explain the requirements on
filesystem code for that to happen.

Signed-off-by: Jonathan Nieder <[email-masked]>
---
Am I understanding the problem here correctly?  It seems to me
that ext2/3/4, tmpfs, ntfs, and so on shouldn’t have problems
with USE_NSEC, and all that is left is the monster that is
networked filesystems.

 Documentation/technical/racy-git.txt |   10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/Documentation/technical/racy-git.txt b/Documentation/technical/racy-git.txt
index 48bb97f..53aa0c8 100644
--- a/Documentation/technical/racy-git.txt
+++ b/Documentation/technical/racy-git.txt
@@ -42,10 +42,12 @@ compared, but this is not enabled by default because this member
 is not stable on network filesystems.  With `USE_NSEC`
 compile-time option, `st_mtim.tv_nsec` and `st_ctim.tv_nsec`
 members are also compared, but this is not enabled by default
-because the value of this member becomes meaningless once the
-inode is evicted from the inode cache on filesystems that do not
-store it on disk.
-
+because in-core timestamps can have finer granularity than
+on-disk timestamps, resulting in meaningless changes when an
+inode is evicted from the inode cache.  See commit 8ce13b0
+of git://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git
+([PATCH] Sync in core time granuality with filesystems,
+2005-01-04).
 
 Racy git
 --------
-- 
1.6.5.rc1.199.g596ec