[CRIU] Dump Failure with 3.18 and OverlayFS

[Saied Kazemi]

Hi Andrew and Pavel,

CRIU fails to dump a Docker container created on 3.18 with OverlayFS with
the following error message:

(00.176154) Error (files-reg.c:821): Unable to look up the 37 mount

I do not find mnt_id 37 anywhere (neither in the container's mount
namespace nor in the global namespace).

Before digging deeper, wanted to quickly check if you've seen this problem
before.  As you know, starting with 3.18, OverlayFS is the preferred
storage driver for Docker so CRIU needs to support it.

I have attached dump.log.  Also, below is a snippet of my terminal.

Thanks,

--Saied


# pwd
/proc/16030

# ls -l fd
total 0
lr-x------ 1 root root 64 Apr 13 12:58 0 -> /dev/null
l-wx------ 1 root root 64 Apr 13 12:58 1 -> pipe:[147784]
lrwx------ 1 root root 64 Apr 13 12:58 10 -> socket:[191845]
l-wx------ 1 root root 64 Apr 13 12:58 2 ->
/usr/local/nginx-streaming/logs/error.log
lrwx------ 1 root root 64 Apr 13 12:58 3 -> socket:[191844]
l-wx------ 1 root root 64 Apr 13 12:58 4 ->
/usr/local/nginx-streaming/logs/access.log
l-wx------ 1 root root 64 Apr 13 12:58 5 ->
/var/log/nginx-streaming/access-streaming.log
l-wx------ 1 root root 64 Apr 13 12:58 6 ->
/var/log/nginx-streaming/error-streaming.log
l-wx------ 1 root root 64 Apr 13 12:58 7 ->
/usr/local/nginx-streaming/logs/error.log
lrwx------ 1 root root 64 Apr 13 12:58 8 -> socket:[191837]
lrwx------ 1 root root 64 Apr 13 12:58 9 -> socket:[191838]

# grep 37 fdinfo/*
fdinfo/2:mnt_id: 37
fdinfo/4:mnt_id: 37
fdinfo/5:mnt_id: 37
fdinfo/6:mnt_id: 37
fdinfo/7:mnt_id: 37

# cat mountinfo
66 39 0:30 / / rw,relatime - overlay overlay
rw,lowerdir=/sda2/docker/overlay/f5296f2a5837f999642df5f17fe9ccdfcf5261eafc16282a54f31fadb6121fac/root,upperdir=/sda2/docker/overlay/064769518b7a26b601c199cbf806682a48f44755f934e2b9261f5515bcadfad0/upper,workdir=/sda2/docker/overlay/064769518b7a26b601c199cbf806682a48f44755f934e2b9261f5515bcadfad0/work
67 66 0:32 / /proc rw,nosuid,nodev,noexec,relatime - proc proc rw
68 66 0:33 / /dev rw,nosuid - tmpfs tmpfs rw,mode=755
69 68 0:34 / /dev/shm rw,nosuid,nodev,noexec,relatime - tmpfs shm
rw,size=65536k
70 68 0:31 / /dev/mqueue rw,nosuid,nodev,noexec,relatime - mqueue mqueue rw
71 68 0:35 / /dev/pts rw,nosuid,noexec,relatime - devpts devpts
rw,gid=5,mode=620,ptmxmode=666
72 66 0:36 / /sys ro,nosuid,nodev,noexec,relatime - sysfs sysfs ro
73 66 8:2
/docker/containers/064769518b7a26b601c199cbf806682a48f44755f934e2b9261f5515bcadfad0/resolv.conf
/etc/resolv.conf rw,relatime - ext4 /dev/sda2 rw,data=ordered
74 66 8:2
/docker/containers/064769518b7a26b601c199cbf806682a48f44755f934e2b9261f5515bcadfad0/hostname
/etc/hostname rw,relatime - ext4 /dev/sda2 rw,data=ordered
75 66 8:2
/docker/containers/064769518b7a26b601c199cbf806682a48f44755f934e2b9261f5515bcadfad0/hosts
/etc/hosts rw,relatime - ext4 /dev/sda2 rw,data=ordered
40 67 0:32 /sys /proc/sys ro,nosuid,nodev,noexec,relatime - proc proc rw
41 67 0:32 /sysrq-trigger /proc/sysrq-trigger
ro,nosuid,nodev,noexec,relatime - proc proc rw
42 67 0:32 /irq /proc/irq ro,nosuid,nodev,noexec,relatime - proc proc rw
43 67 0:32 /bus /proc/bus ro,nosuid,nodev,noexec,relatime - proc proc rw
44 67 0:33 /null /proc/kcore rw,nosuid - tmpfs tmpfs rw,mode=755

# grep -w 37 /proc/[1-9]*/mountinfo
#
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openvz.org/pipermail/criu/attachments/20150413/982d792c/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: dump.log
Type: text/x-log
Size: 21373 bytes
Desc: not available
URL: <http://lists.openvz.org/pipermail/criu/attachments/20150413/982d792c/attachment-0001.bin>