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Date: Fri, 4 Mar 2005 16:45:53 -0800
From: Andrew Morton <akpm@osdl.org>
To: Badari Pulavarty <pbadari@us.ibm.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] 2.6.11-mm1 "nobh" support for ext3 writeback mode
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Badari Pulavarty <pbadari@us.ibm.com> wrote:
>
> > What's all this doing?  (It needs comments please - it's very unobvious).
> 
> All its trying to do is - to make sure the page is uptodate so that
> it can zero out the portion thats needed. 

OK.

> I can do getblock() and ll_rw_block(READ) instead. I was
> trying to re-use the code and mpage_readpage() drops the lock.
> What do you think ?

Can you just call ->prepare_write, as nobh_truncate_page() does?  That'll
cause a nested transaction, but that's legal.