Re: BTRFS hang with 3.16-rc5 (and also with 3.16-rc4)

[Liu Bo <bo.li.liu@oracle.com>]

On Mon, Jul 28, 2014 at 01:11:19PM +0200, Torbjørn wrote:
> On 28. juli 2014 12:00, Liu Bo wrote:
> <snip>
> >This seems to be incomplete(Looks like dmesg has reached its buffer size limit),
> >does /var/log/message have the whole stack info?
> >
> >thanks,
> >-liubo
> Hi,
> 
> Complete log was over 40MB. I uploaded everything from boot until
> "blocked for 120 seconds" started to appear.
> If you want all the trailing log as well, let me know.
> 
> https://gist.github.com/anonymous/7958d8917967f727f324

Sorry...still don't get why it's locked up, io_ctl_prepare_pages() has several
callers, and they are properly released from the code level.  And the warnings
printed in the log belong to other btrfs partitions, not the hanged btrfs one,
and we're still not able to know which one holds the free space cache inode page.

Maybe we'd better resort to a bisect between 3.14 and 3.15(I know it'd be a lot
of time though).

Here, doing rsync on compress=lzo full btrfs never hit that problem, shrug...

thanks,
-liubo

> 
> --
> Torbjørn