Re: Post ext3 conversion problems

[Sean Greenslade <sean@seangreenslade.com>]

On Tue, Sep 20, 2016 at 04:51:21PM -0400, Sean Greenslade wrote:
> On Tue, Sep 20, 2016 at 01:02:38PM +0800, Qu Wenruo wrote:
> > > Glad to hear you've found the core of the issue.
> > > 
> > > At this point, I can trigger it immediately. As soon as I log in and run
> > > dmenu, it will attempt to rebuild its cache file (small text file that's
> > > just a list of all executables in the PATH). Once that write happens,
> > > the bug triggers and the fs goes read only.
> > 
> > Rewrite? Or write into new inode?
> > 
> > And is the same inode always causing the problem?
> 
> It's not always the same. It seems like whatever triggers a write first
> is what kills it. I went to test it, and this time it triggered on my
> .bash_history file. I have bash set up with "history -a", so presumably
> that was an append, not an overwrite.
> 
> To cut down on the number of variables, I booted my system with the
> "rescue" systemd target, then su'd to my user. Simply running a few
> commands (with the history -a writes that bash triggered) was enough to
> trigger the bug. This is on 4.8.0-rc6, with the following compile time
> options enabled:
> 
> CONFIG_BTRFS_FS_RUN_SANITY_TESTS=y
> CONFIG_BTRFS_DEBUG=y
> CONFIG_BTRFS_ASSERT=y
> 
> If I run the stock Arch kernel (4.7.2 at the moment), the issue still
> appears, but it takes longer. My most reliable trigger is Firefox, whose
> constant DB writes will trigger it within minutes.

Is there anything I can do to help this along? I can build experimental
patches, set up long running scripts, run tests, whatever is necessary.

Thanks,

--Sean