Inconsistent state of containers when running out of disk space with btrfs

[discordianfish]

Hi,

a few days ago one docker host ran out of disk space on the /var/lib/docker btrfs partition. This caused some very odd behavior like processes inside the container dying without the container exiting, which made the container unkillable because docker complained that the registered pid can't be found.
Can't provide much details right now because I had to recover the system and had no time to gather more details. But I believe this should be fairly easy to reproduce.

I consider this low priority but still a case that can be handled better.

[unclejack]

Adding quota support is tracked by issue #3804. The underlying cause for the problems which have led to this issue are actually the same as those from #5685 and that remains a problem.

I'll close this issue and we can continue the discussion on #5685.