From: Pavel Machek <pavel@suse.cz>
To: Chris Mason <chris.mason@oracle.com>
Cc: Christoph Hellwig <hch@infradead.org>,
Eric Sesterhenn <snakebyte@gmx.de>,
linux-kernel@vger.kernel.org, linux-btrfs@vger.kernel.org
Subject: Re: Warning and BUG with btrfs and corrupted image
Date: Thu, 5 Feb 2009 14:50:11 +0100 [thread overview]
Message-ID: <20090205135011.GA2294@elf.ucw.cz> (raw)
In-Reply-To: <1233838959.15948.6.camel@think.oraclecorp.com>
On Thu 2009-02-05 08:02:39, Chris Mason wrote:
> On Thu, 2009-02-05 at 10:02 +0100, Pavel Machek wrote:
> > > > > CONFIG_*_DEBUG means include *debug* code there to help developers,
> > > > > including adding additional failure tests into the kernel. Besides,
> > > > > which bit of "don't turn it on unless you are an XFS developer"
> > > > > don't you understand?
> > > >
> > > > Yes, but DEBUG code is normally to help debugging, not to crash
> > > > kernels.
> > >
> > > Crashing the kernel at exactly the point a problem is detected
> > > is often the simplest way of debugging the problem.
> > >
> > > e.g. CONFIG_VM_DEBUG=y turns on VM_BUG_ON() which crashes the kernel
> > > whenever it detects something wrong. Do I turn it on? Yes. Do i
> >
> > That's different. User is not supposed to be able to trigger
> > VM_BUG_ON().
> >
> > > complain about it when I hit a VM_BUG_ON()? No, I report the
> > > bug and move on. If you turn on a DEBUG option, then you are
> > > asking the system to behave in a way useful to a developer,
> > > not an end user. That includes panicing when something wrong
> > > is detected.
> >
> > Imagine vm going panic() on mkdir("/lost+found")...
>
> It is up to the XFS developers to decide what their debugging options
> do.
Eh?
> The whole point of panicing is so that you can collect important
> information about the system at the time of the error condition. When
> this option is compiled on, panic on mkdir is exactly what they are
> asking for.
>
> If you don't want it, don't compile it in. The Kconfig text is very
> clear.
No, I'd not expect that option to panic systems. That's why I
suggested:
diff --git a/fs/xfs/Kconfig b/fs/xfs/Kconfig
index 29228f5..b7ac847 100644
--- a/fs/xfs/Kconfig
+++ b/fs/xfs/Kconfig
@@ -77,4 +77,7 @@ config XFS_DEBUG
Note that the resulting code will be HUGE and SLOW, and probably
not useful unless you are debugging a particular problem.
+ Turning this option on will result in kernel panicking any time
+ it detects on-disk corruption.
+
Say N unless you are an XFS developer, or you play one on TV.
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2009-02-05 13:50 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-13 14:21 Warning and BUG with btrfs and corrupted image Eric Sesterhenn
2009-01-13 14:40 ` Chris Mason
2009-01-13 14:43 ` Eric Sesterhenn
2009-01-15 2:13 ` Chris Mason
2009-01-18 17:40 ` Pavel Machek
2009-01-20 6:31 ` Eric Sesterhenn
2009-01-20 9:34 ` Pavel Machek
2009-01-20 10:11 ` Dave Chinner
2009-01-20 10:15 ` Eric Sesterhenn
2009-01-20 12:59 ` Dave Chinner
2009-01-20 13:28 ` Christoph Hellwig
2009-01-20 22:20 ` Pavel Machek
2009-01-21 4:00 ` Dave Chinner
2009-01-26 16:27 ` Pavel Machek
2009-02-01 1:40 ` Dave Chinner
2009-02-04 18:29 ` Pavel Machek
2009-02-05 8:59 ` Dave Chinner
2009-02-05 9:02 ` Pavel Machek
2009-02-05 13:02 ` Chris Mason
2009-02-05 13:50 ` Pavel Machek [this message]
2009-02-05 14:19 ` jim owens
2009-02-25 19:54 ` Pavel Machek
2009-01-20 17:34 ` Eric Sesterhenn
2009-01-20 22:18 ` Pavel Machek
2009-01-21 9:36 ` Eric Sesterhenn
2009-01-21 3:57 ` Corrupted XFS log replay oops. (was Re: Warning and BUG with btrfs and corrupted image) Dave Chinner
2009-01-21 4:03 ` Nick Piggin
2009-01-22 4:37 ` [PATCH] Re: Corrupted XFS log replay oops Dave Chinner
2009-01-22 5:50 ` Felix Blyakher
2009-01-22 6:11 ` Christoph Hellwig
2009-01-22 8:35 ` Eric Sesterhenn
2009-01-22 10:06 ` Eric Sesterhenn
2009-01-22 23:37 ` Dave Chinner
2009-01-23 1:10 ` Dave Chinner
2009-01-22 23:35 ` Dave Chinner
2009-01-23 0:02 ` Dave Chinner
2009-01-23 0:06 ` Christoph Hellwig
2009-01-23 6:20 ` Felix Blyakher
2009-01-21 4:03 ` Corrupted XFS log replay oops. (was Re: Warning and BUG with btrfs and corrupted image) Dave Chinner
2009-01-20 13:11 ` Warning and BUG with btrfs and corrupted image Chris Mason
2009-01-20 16:51 ` Eric Sesterhenn
2009-01-22 2:15 ` Phillip Lougher
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