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Gmane
From: Cyril Brulebois <cyril.brulebois <at> kerlabs.com>
Subject: Blocking rename?
Newsgroups: gmane.linux.file-systems.aufs.user
Date: Thursday 10th July 2008 16:58:13 UTC (over 9 years ago)
Hi,

when using aufs as union FS for a Debian LiveCD (using the
http://debian-live.alioth.debian.org/
tools), I've encountered the
following problem: I'm able to "apt-get install $package", but not to
"apt-get update". Using strace, I've noticed the following rename call
seems blocking:
2490  stat64("/var/lib/apt/lists/partial/", {st_mode=S_IFDIR|0755,
st_size=3, ...}) = 0
2490  stat64("/var/cache/apt/archives/partial/", {st_mode=S_IFDIR|0755,
st_size=3, ...}) = 0
2490 
unlink("/var/lib/apt/lists/partial/ftp.fr.debian.org_debian_dists_lenny_Release.gpg")
= -1 ENOENT (No such file or directory)
2490 
stat64("/var/lib/apt/lists/ftp.fr.debian.org_debian_dists_lenny_Release.gpg",
{st_mode=S_IFREG|0644, st_size=189, ...}) = 0
2490 
rename("/var/lib/apt/lists/ftp.fr.debian.org_debian_dists_lenny_Release.gpg",
"/var/lib/apt/lists/partial/ftp.fr.debian.org_debian_dists_lenny_Release.gpg.reverify"

I'm attaching the whole output of the following command:
$ sudo strace -f -o /tmp/livecd-apt-get-update.log

After that, I tried to rename files with very long filenames in my
$HOME directory, no problem. And when I tried to look into the
/var/lib/apt/lists directory, I wasn't even able to cd into it.
$ ls /var/lib       # ok
$ ls /var/lib/apt   # blocking

I've uploaded a quite minimal ISO to the following location, so that
you can try yourself. It's a quite minimal image, so that it doesn't
waste too much bandwidth, but it should help you reproduce the bug.
You can try it out into qemu or virtualbox, for example, just press
Enter at the boot prompt, and once you have the user prompt, use the
sudo command I pasted above.

    http://people.debian.org/~kibi/aufs-tmp/
(60MB)

It'll disappear in some time, but readers of the archives are
welcome to contact me if they need it afterwards.

The configuration is the following: 2.6.24-1-486 (from Debian),
its config file is stored under /boot. The aufs version is 20080129.
I've also reproduced this with the 20080609 aufs snapshot (using the
Debian package), but also with the 20080707 snapshot, and I've got
the very same trace. Other people from #debian-live (irc.debian.org)
are also experiencing the very same problem. I've also reproduced it
with a (modified) 2.6.20 Linux package, so I think it's quite
independent from the kernel version.

We aren't experiencing any troubles on "real" systems, only on
LiveCDs so I think that has nothing to do with apt/apt-get.

Do you have any hint about what could be going wrong? Thanks in
advance.

Cheers,

-- 
Cyril Brulebois
 
CD: 3ms