support multi tmpfs in cadvisor

[zouyee]

support multi tmpfs in cadvisor
fix kubernetes/kubernetes#81575

[zouyee]

related PR: #1667
@dashpole PTAL

[dashpole]

I don't fully understand the issue. Would you mind explaining it in detail?

[zouyee]

Have multiple tmpfs mounts which have different major:minor pairs, e.g.:

root@hostname:/# cat /proc/self/mountinfo | grep tmpfs

404 394 0:18 / /dev/shm rw,nosuid,nodev shared:22 - tmpfs tmpfs rw,seclabel
1715 278 0:36 /var/lib/kubernetes/ssl/kubelet /var/lib/kubernetes/ssl ro,relatime shared:1 - tmpfs tmpfs rw,seclabel,mode=755
...
1775 278 0:36 /var/lib/kubelet /var/lib/kubelet rw,relatime shared:1 - tmpfs tmpfs rw,seclabel,mode=755
1820 278 0:36 /etc/kubernetes /etc/kubernetes rw,relatime shared:1 - tmpfs tmpfs rw,seclabel,mode=755
1845 278 0:36 /etc/ssl/certs /etc/ssl/certs ro,relatime shared:1 - tmpfs tmpfs rw,seclabel,mode=755
1877 278 0:36 /etc/hosts /etc/hosts rw,relatime shared:1 - tmpfs tmpfs rw,seclabel,mode=755

_, ok := partitions[mount.Source]
If mount.Source is tmpfs, other mountpoints which source also is tmpfs, will be escape.

[dashpole]

Right, I see why it exits. I'm trying to figure out why this works for other filesystems, but not for tmpfs. Is mount.Source normally unique?

[zouyee]

mount.Source is normally unique, but the uniqueness of the mount point is more universal.

[dashpole]

Sorry for the delay, this LGTM.

[dashpole]

You will have to rebase. Ping the PR after you do that so I can merge it.

[zouyee]

@dashpole PTAL

[dashpole]

/retest