Linux Btrfs filesystem development
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From: Marc MERLIN <marc@merlins.org>
To: Hugo Mills <hugo@carfax.org.uk>, Liu Bo <bo.li.liu@oracle.com>,
	Chris Mason <clm@fb.com>,
	linux-btrfs@vger.kernel.org
Subject: Re: 4.11.0: kernel BUG at fs/btrfs/ctree.h:1779!
Date: Fri, 19 May 2017 17:47:48 -0700	[thread overview]
Message-ID: <20170520004748.GA29894@merlins.org> (raw)
In-Reply-To: <20170520003747.GO9701@carfax.org.uk>

On Sat, May 20, 2017 at 12:37:47AM +0000, Hugo Mills wrote:
> > Can I make another plea for just removing all those BUG/BUG_ON?
> > They really have no place in production code, there is no excuse for a
> > filesystem to bring down the entire and in the process not even tell you
> > which of your filesystems had the issue to start with.
> > 
> > Could this be made part of a cleanup for this build to remove them all?
> 
>    The removal of these has been an ongoing process for at least the
> last 5 years.
 
That's great news, thanks. I guess I'm a bit edgy because I've hit too many
of them already :) but glad to hear that there are a lot fewer now.

>    I don't understand the specifics of the kernel code in question(*),
> but compared to 5 years ago, btrfs has got rid of most of the
> BUG_ONs(**) a few years ago. The remaining ones are probably
> complicated to deal with in any way more elegant than just stopping.

The biggest problem is that those BUG* do not even tell you where the
problem.
The assumption that you'd only ever have a single btrfs filesystem mounted,
is flawed to say the least :)
(I have 5 different ones on my server)

>    I recall seeing someone's stats on BUG_ON locations a couple of
> years ago, and btrfs had managed to get the number of locations down
> below XFS (but no other FS). It's a kind of success, at least...

Good to know, thanks, and thanks to anyone who has worked on removing those.

Marc
-- 
"A mouse is a device used to point at the xterm you want to type in" - A.S.R.
Microsoft is to operating systems ....
                                      .... what McDonalds is to gourmet cooking
Home page: http://marc.merlins.org/  

  reply	other threads:[~2017-05-20  0:48 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-19  4:16 4.11.0: kernel BUG at fs/btrfs/ctree.h:1779! Marc MERLIN
2017-05-19 19:03 ` Liu Bo
2017-05-20  0:11   ` Marc MERLIN
2017-05-20  0:37     ` Hugo Mills
2017-05-20  0:47       ` Marc MERLIN [this message]
2017-05-20  0:57         ` Hugo Mills
2017-05-20  1:25           ` Marc MERLIN
2017-05-20  1:48             ` Hugo Mills

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