Re: 3.15.1: kernel BUG at fs/btrfs/locking.c:269

[Marc MERLIN <marc@merlins.org>]

On Fri, Jul 04, 2014 at 01:29:29PM +0800, Wang Shilong wrote:
> >Well, I explained the problem, ext4 and others of course tell me which 
> >devid
> >an error is on, hopefully btrfs will able to do so in the near future.
>
> So it is ok for you to print one of btrfs filesystem device(for example
> device name) ? maybe it is not really physical address the metadata
> locates in, this is easier.

Yes, the device name is great, now I can see which of my 3 filesystems has a
problem, that's a start.
Next would be knowing which filename this occurred in, but I understand this
would be harder to get from that point in the code.
Ideally scrub should be able to find that problem and report it, at least I
would know which filesystem to rescan for errors:

> >Back to the original problem, would you agree that
> >find / -type f -print0 | xargs grep . >/dev/nul?

I'll also have to try this to see if I get lucky with it :)

> +       printk_ratelimited("BTRFS (device: %s) parent transid verify 
> failed on %llu wanted %llu found %llu\n",
> +                       eb->fs_info->sb->s_id, eb->start,
> +                       parent_transid, btrfs_header_generation(eb));

That looks great. Ideally all such errors would look like this.

Thanks for looking into this, I appreciate it.

Best,
Marc
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