[lxc-devel] LXC_DIRECTORY remounted read-only

[Serge Hallyn]

Uh.  what the...

lxc_spawn closes the pinfd right before returning success.

This is a bug in commit 2b0e17e48f4f55ddfcde74d1f00932837fa2cfda

Thanks for reporting it!

-serge

Quoting Harald Dunkel (harri at afaics.de):
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> Hi Serge,
> 
> On 08/26/13 13:41, Serge Hallyn wrote:
> > 
> > Lxc should be creating a $lxcpath/$lxcname/rootfs.hold and keeping that open for write, which should prevent the remount -o ro.  Does that file exist in your case?  Which filesystem is mounted on /export/lxc?
> > 
> 
> Filesystem is ext4.
> 
> It seems that this problem comes up, if I run "halt" within
> the container. Using lxc-stop on the server I couldn't
> reproduce it by now. Sample session:
> 
> 
> {root at cecil:~ 501} lxc-create -t debian -n no2
> debootstrap is /usr/sbin/debootstrap
> Checking cache download in /var/cache/lxc/debian/rootfs-squeeze-amd64 ...
> Copying rootfs to /usr/lib/x86_64-linux-gnu/lxc...Generating locales (this might take a while)...
> Generation complete.
> update-rc.d: using dependency based boot sequencing
> update-rc.d: using dependency based boot sequencing
> update-rc.d: using dependency based boot sequencing
> update-rc.d: using dependency based boot sequencing
> Root password is 'root', please change !
> 
> {root at cecil:~ 501} mount | grep /export
> /dev/md0p4 on /export type ext4 (rw,noatime,stripe=32,data=ordered)
> 
> {root at cecil:~ 501} lxc-start -n no2
> INIT: version 2.88 booting
> Using makefile-style concurrent boot in runlevel S.
> :
> :
> 
> Debian GNU/Linux 6.0 no2 console
> 
> no2 login: root
> Password:
> Linux no2 3.10.10 #1 SMP PREEMPT Fri Aug 30 06:47:21 CEST 2013 x86_64
> 
> root at no2:~# passwd
> Enter new UNIX password:
> Retype new UNIX password:
> passwd: password updated successfully
> root at no2:~# halt
> 
> Broadcast message from root at no2 (console) (Sat Aug 31 06:19:47 2013):
> 
> The system is going down for system halt NOW!
> INIT: Switching to runlevel: 0
> INIT: Sending processes the TERM signal
> Using makefile-style concurrent boot in runlevel 0.
> Asking all remaining processes to terminate...done.
> All processes ended within 2 seconds....done.
> Deconfiguring network interfaces...ifdown: failed to open statefile /etc/network/run/ifstate: Read-only file system
> failed.
> Cleaning up ifupdown...rm: cannot remove `/etc/network/run/ifstate': Read-only file system
> Will now halt.
> 
> {root at cecil:~ 501} mount | grep /export
> /dev/md0p4 on /export type ext4 (ro,noatime,stripe=32,data=ordered)
> 
> {root at cecil:~ 501} ls -al /export/lxc/no2
> total 16
> drwxr-xr-x  3 root root 4096 Aug 31 08:19 .
> drwxr-xr-x  8 root root 4096 Aug 31 08:18 ..
> - -rw-r--r--  1 root root 1001 Aug 31 08:18 config
> drwxr-xr-x 20 root root 4096 Aug 31 08:19 rootfs
> - -rw-------  1 root root    0 Aug 31 08:19 rootfs.hold
> 
> 
> 
> AFAICS the file system is remounted read-only, while the container
> is still active.
> 
> Hope this helps.
> Harri
> 
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