Public bug reported:
The lastest Lucid Lynx kernels generate file modification timestamps
with a precision of merely 0.5 seconds on filesystems which support a
much higher timestamp resolution, e.g. ext4 or tmpfs. In other words,
the test command
{ while true; do echo >t; ls --full-time t; rm t; done; } | uniq
prints exactly two lines per second.
It seems that this bug has been introduced with kernel 2.6.32-45.
I'm able to reproduce it on three platforms:
- a HP desktop PC with Ubuntu Lucid Lynx x86_64 Desktop Edition
- a VirtualBox VM on OS X with Ubuntu Lucid Lynx x86_64 Desktop Edition
- a VirtualBox VM on OS X with Ubuntu Lucid Lynx x86_64 Server Edition
The affected kernels include the latest Lucid Lynx kernels:
2.6.32-45-generic, 2.6.32-46-generic, 2.6.32-47-generic, and 2.6.32-47-server
are affected.
2.6.32-45-server and 2.6.32-46-server most likely as well.
The kernels 2.6.32-44-generic and 2.6.32-38-server are fine,
2.6.32-44-server most likely as well. (Fine is this context meaning that
the provided test command prints exactly 100 unique timestamps per
second when run on these kernel versions.)
I discovered this bug while giving Subversion 1.8 RC2 a try. One test
case kept failing due to Subversion's unfortunate assumption that
sleeping for one millisecond would be enough to get different timestamps
afterwards, combined with the low 0.5 seconds granularity of
modification filestamps described in this report. (Please see thread
http://mail-archives.apache.org/mod_mbox/subversion-
users/201305.mbox/%3C519DDBE3.5040909%40web.de%3E if you're interested
in details.)
IMHO this bug has a good chance of affecting other version control
systems as well, because many rely on changed timestamps to recognize
modified files.
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1185730
Title:
Very low granularity of file modification timestamps
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1185730/+subscriptions
--
ubuntu-bugs mailing list
ubuntu-bugs@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
