linux-kernel - Re: [PATCH v2 10/18] mm: teach truncate_inode_pages_range() to handle non page aligned ranges

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Date:	Thu, 21 Feb 2013 09:33:56 +0100 (CET)
From:	Lukáš Czerner <lczerner@...hat.com>
To:	Lukáš Czerner <lczerner@...hat.com>
cc:	Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
	linux-ext4@...r.kernel.org, Hugh Dickins <hughd@...gle.com>
Subject: Re: [PATCH v2 10/18] mm: teach truncate_inode_pages_range() to handle
 non page aligned ranges

On Fri, 8 Feb 2013, Lukáš Czerner wrote:

> Date: Fri, 8 Feb 2013 10:08:05 +0100 (CET)
> From: Lukáš Czerner <lczerner@...hat.com>
> To: Andrew Morton <akpm@...ux-foundation.org>
> Cc: Lukas Czerner <lczerner@...hat.com>, linux-mm@...ck.org,
>     linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
>     linux-ext4@...r.kernel.org, Hugh Dickins <hughd@...gle.com>
> Subject: Re: [PATCH v2 10/18] mm: teach truncate_inode_pages_range() to handle
>      non page aligned ranges

..snip..

> > > +	/*
> > > +	 * 'start' and 'end' always covers the range of pages to be fully
> > > +	 * truncated. Partial pages are covered with 'partial_start' at the
> > > +	 * start of the range and 'partial_end' at the end of the range.
> > > +	 * Note that 'end' is exclusive while 'lend' is inclusive.
> > > +	 */
> > 
> > That helped ;)  So the bytes to be truncated are
> > 
> > (start*PAGE_SIZE + partial_start) -> (end*PAGE_SIZE + partial_end) - 1
> > 
> > yes?
> 
> The start of the range is not right, because 'start' and 'end'
> covers pages to be _fully_ truncated. See the while cycle and 
> then 'if (partial_start)' condition where we search for the
> page (start - 1) and do_invalidate within that page.
> 
> So it should be like this:
> 
> 
> (start*PAGE_SIZE - partial_start*(PAGE_SIZE - partial_start) ->
> (end*PAGE_END + partial_end) - 1
> 
> 
> assuming that you want the range to be inclusive on both sides.
> 
> -Lukas
> 

Hi Andrew,

what's the status of the patch set ? Do you have any more comments
or questions ? Can we get this in in this merge window ?

Thanks!
-Lukas