#76 — hang/deadlock/livelock when reading from or writing to zfs filesytems.

I haven't quite narrowed down the cause(s) of the problem, but I can describe the symptoms. Once it happens, reads and writes simply stop happening. Some apps, like emacs, are effectively single threaded and block on the io, others aren't and keep working. Eventually X decides to do some io and then you're reaching for the reset button. Even running 'reboot' from a user shell will hang, probably because it's searching the path, which includes ~/bin which is on a zfs filesystem.

There's one case that I can reproduce at will. I record certain information every day in emacs planner-mode (what hours I worked on which projects, etc), and loading the daily planner file will invariably lock up emacs. I'll attach an strace of emacs, which is rather odd.

I started with the 0.6.0 rpm, then upgraded to 0.6.9 to test the latest rpm and in the hope that this would go away. Now I'm running the latest from the git repository with the same problem.

I've got a script that takes snapshots of the majority of my file systems at regular intervals, which I disabled temporarily to see if that helps, but the problem remains.