Re: btrfs hang in flush-btrfs-5

[Jeremy Sanders <jeremy@jeremysanders.net>]

Josef Bacik wrote:

> On 07/11/2011 07:40 AM, Jeremy Sanders wrote:
>> Jeremy Sanders wrote:
>> 
>>> Hi - I'm trying btrfs with kernel 2.6.38.8-32.fc15.x86_64 (a Fedora
>>> kernel). I'm just doing a tar-to-tar copy onto the file system with
>>> compress- force=zlib. Here are some traces of the stuck processes.
>> 
>> I've managed to reproduce the hang using the latest btrfs from the
>> repository. I had to remove some of the tracing lines to get it to
>> compile under 2.6.38.8 and an ioctl which wasn't defined. Here is is
>> where it is stuck:
>> 
> 
> Hrm well that is just unlikely and hard to hit.  Will you try this and
> see if it helps you?  Thanks,

It's got quite a bit further past than where it got before and hasn't 
crashed yet. I will let you know when it has finished ok.

I see that the btrfs-delalloc (rather than endio-write) thread is taking up 
100% of CPU and the write speed seems to have dropped during the copying, 
however. The copy started with using endio-write fully on both cores and now 
is using dealloc a lot.

Jeremy