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Date: Tue, 31 Jul 2001 12:34:13 +1000
From: Andrew Morton <akpm@zip.com.au>
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To: Christoph Hellwig <hch@caldera.de>
CC: Hans Reiser <reiser@namesys.com>, linux-kernel@vger.kernel.org
Subject: Re: ReiserFS / 2.4.6 / Data Corruption
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Christoph Hellwig wrote:
> 
> For example I've just turned of the debugging on my ext3-using boxens.

FYI...  CONFIG_JBD_DEBUG is really just that - debug stuff.  Mainly,
it enables the printks which are controlled by /proc/sys/fs/jbd-debug.

Early on, sct made the decision that the assertion checks in ext3:

	akpm-1:/usr/src/ext3> grep -r ASSERT . | wc -l
	    187

cannot be disabled.  Each and every one of these will nicely
crash the machine.  The idea being, as you stated earlier,
that data integrity is golden - if we detect an inconsistency
we take the machine out and let recovery fix it up.

Turns out that at present we're over-aggressive on this. A modest
filesytem inconsistency (bit already free in bitmap, whatever)
or an IO error could force a panic.  Stephen is working on changing
the fs to be more selective in its handling of errors - less severe
errors will turn the fs readonly.

I would support your decision to enable reiserfs checking.  It's
a valuable feature.  It can save your data from hardware failures
as well as software failures.  Perhaps Hans' team should look into
moving the expensive checks into a different ifdef.

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