Re: [PATCH v2 10/18] mm: teach truncate_inode_pages_range() to handlenon page aligned ranges

From: Lukáš Czerner
Date: Thu Feb 21 2013 - 03:37:57 EST


On Fri, 8 Feb 2013, Lukáš Czerner wrote:

> Date: Fri, 8 Feb 2013 10:08:05 +0100 (CET)
> From: Lukáš Czerner <lczerner@xxxxxxxxxx>
> To: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Lukas Czerner <lczerner@xxxxxxxxxx>, linux-mm@xxxxxxxxx,
> linux-kernel@xxxxxxxxxxxxxxx, linux-fsdevel@xxxxxxxxxxxxxxx,
> linux-ext4@xxxxxxxxxxxxxxx, Hugh Dickins <hughd@xxxxxxxxxx>
> 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