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From: Evgeniy Dushistov <dushistov@mail.ru>
To: Alessio Igor Bogani <abogani@kernel.org>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	Tim Bird <tim.bird@am.sony.com>
Subject: Re: [PATCH] ufs: Check if page has buffers before calling page_buffers()
Date: Wed, 2 Feb 2011 07:23:47 +0300	[thread overview]
Message-ID: <20110202042347.GA3870@maclin> (raw)
In-Reply-To: <1296595418-2457-1-git-send-email-abogani@kernel.org>

On Tue, Feb 01, 2011 at 10:23:38PM +0100, Alessio Igor Bogani wrote:
> In ufs_change_blocknr() we have called page_buffers() without checking if the
> page actually had pages attached to it and this could cause a BUG oops.
> 

This looks wrong for me. May be I missed something?
Put little more context here.
In ufs the tail of small files consists of fragments (usually 2K),
the rest of file consists of blocks (usually 16K=8 fragments).
When file is growing, and tail become too big (8 fragments)
we allocate one block and move content of 8 fragments to it.

So in our case we reach (during realocation) point when
!page_has_buffers(page) (how?) and in your patch you suggest
just ignore such buffer (in terms of ufs - fragments),
in other words silently corrupt user data.
May be there is better variant?


-- 
/Evgeniy

  reply	other threads:[~2011-02-02  4:23 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-01 21:23 [PATCH] ufs: Check if page has buffers before calling page_buffers() Alessio Igor Bogani
2011-02-02  4:23 ` Evgeniy Dushistov [this message]
2011-02-02 17:57   ` Alessio Igor Bogani

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