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Subject: Re: [Ext2-devel] bug in ext3 htree rename: doesn't delete old
	name, leaves ino with bad nlink
From: Jeremy Fitzhardinge <jeremy@goop.org>
To: chrisl@vmware.com
Cc: Ext2 devel <ext2-devel@lists.sourceforge.net>,
       Linux Kernel List <linux-kernel@vger.kernel.org>
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On Tue, 2002-11-05 at 13:24, chrisl@vmware.com wrote:
> Thanks again for the nice bug report.

Thanks for looking at it so quickly.  I want ext3+htree to stabilise as
quickly as possible, and since I had a nice reproducible bug, I may as
well make the most of it.

> I think I understand the problem now. What happen was, in ext3_rename,
> it will first add the new entry to directory and then remove the
> old entry. In this case, when add a new entry to the directory
> cause a leaf node split. And the old entry is in the very same
> leaf node. After split, the old entry have been move to another
> leaf node. But ext3_rename still holding the old pointer and bh
> to the old leaf node.

Yes, I would have guessed that it was related to a tree split.  The
interesting thing to me is that it happened twice in this particular
run, and yet it must be a fairly uncommon occurrence overall (otherwise
it would have been reported before).  I wonder if it really is a rare
event, or it has just gone unnoticed?

> This also raise an interesting question, after split leave node,
> do we need to update the dentry cache for the change?

Update it in what way?  In principle a rename is an atomic operation, so
other things shouldn't be able to observe the directory in an
intermediate state.

	J


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