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Date: Thu, 5 Sep 2002 19:46:49 +0100
From: Christoph Hellwig <hch@infradead.org>
To: Andrea Arcangeli <andrea@suse.de>
Cc: linux-kernel@vger.kernel.org, lord@sgi.com
Subject: Re: 2.4.20pre5aa1
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On Thu, Sep 05, 2002 at 08:41:25PM +0200, Andrea Arcangeli wrote:
> maybe I'm overlooking something but after a short read it seems you have
> no lock in do_truncate->setattr like for all the other fs, so the
> vmtruncate can run under reads and the i_size can change under you and
> in turn you must always read it with i_size_read using asm, like all the
> other fs, if you're not holding the i_sem (and you certainly aren't
> holding the i_sem that frequently, you don't even for writes). this
> because i_sem  is the only lock/sem hold by truncate.  Infact I'm unsure
> how you serialize the i_size writes of truncate against the ones from
> writes, that seems problematic too, the i_size could get a value past
> the last block allocated (in turn corrupting the fs). Please double
> check that I'm wrong, thanks.

I think we should take the XFS-specific inode lock around vmtruncate.
Need to double-check with Steve.

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