From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: Warning and BUG with btrfs and corrupted image Date: Wed, 4 Feb 2009 19:29:51 +0100 Message-ID: <20090204182951.GC4797@elf.ucw.cz> References: <20090118174035.GG1944@ucw.cz> <20090120063150.GC5854@alice> <20090120101119.GB10158@disturbed> <20090120101503.GC17377@alice> <20090120125944.GC10158@disturbed> <20090120132829.GA27429@infradead.org> <20090120222019.GB2320@elf.ucw.cz> <20090121040042.GI10158@disturbed> <20090126162711.GA2083@elf.ucw.cz> <20090201014050.GD24173@disturbed> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: Christoph Hellwig , Eric Sesterhenn , Chris Mason , linux-kernel@vger.kernel.org, linux-btrfs@vger.kernel.org Return-path: In-Reply-To: <20090201014050.GD24173@disturbed> List-ID: On Sun 2009-02-01 12:40:50, Dave Chinner wrote: > On Mon, Jan 26, 2009 at 05:27:11PM +0100, Pavel Machek wrote: > > On Wed 2009-01-21 15:00:42, Dave Chinner wrote: > > > On Tue, Jan 20, 2009 at 11:20:19PM +0100, Pavel Machek wrote: > > > > On Tue 2009-01-20 08:28:29, Christoph Hellwig wrote: > > > > > I think that was the issue with the debug builds. If you do this > > > > > testing always do it without CONFIG_XFS_DEBUG set as with that option > > > > > we intentionally panic on detected disk corruptions. > > > > > > > > Uhuh, *_DEBUG options are not supposed to make kernel less > > > > stable/robust. Should that crashing functionality be guarded with > > > > command line option or something? ext2 has errors=panic mount > > > > option... > > > > > > No, it's a debugging option that is described as: > > > > > > "Say N unless you are an XFS developer, or you play one on TV." > > > > > > Seriously, if you aren't trying to develop XFS stuff then *don't turn it > > > on*. > > > > What about this, then? > > .... > > > + Turning this option on will result in kernel panicking any time > > + it detects on-disk corruption. > > Thin end of a wedge. There's a couple of thousand conditions that > CONFIG_XFS_DEBUG introduces kernel panics on: > > $ grep -r ASSERT fs/xfs |wc -l > 2095 > > > 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. IMO xfs should use errors=panic mount option as ext3 does, but... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html