From: Mark Tinguely <tinguely@sgi.com>
To: Dave Chinner <david@fromorbit.com>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH 2/8] xfs: fix incorrect b_offset initialisation
Date: Thu, 29 Mar 2012 15:43:42 -0500 [thread overview]
Message-ID: <4F74C97E.1090907@sgi.com> (raw)
In-Reply-To: <1333023835-12856-3-git-send-email-david@fromorbit.com>
On 03/29/12 07:23, Dave Chinner wrote:
> From: Dave Chinner<dchinner@redhat.com>
>
> Because we no longer use the page cache for buffering, there is no
> direct block number to page offset relationship anymore.
> xfs_buf_get_pages is still setting up b_offset as if there was some
> relationship, and that is leading to incorrectly setting up
> *uncached* buffers that don't overwrite b_offset once they've had
> pages allocated.
>
> For cached buffers, the first block of the buffer is always at offset
> zero into the allocated memory. This is true for sub-page sized
> buffers, as well as for multiple-page buffers.
>
> For uncached buffers, b_offset is only non-zero when we are
> associating specific memory to the buffers, and that is set
> correctly by the code setting up the buffer.
>
> Hence remove the setting of b_offset in xfs_buf_get_pages, because
> it is now always the wrong thing to do.
>
> Signed-off-by: Dave Chinner<dchinner@redhat.com>
> ---
Looks good.
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
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next prev parent reply other threads:[~2012-03-29 20:43 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-29 12:23 [PATCH 0/8] xfs: clean up unit usage in xfs_buf V2 Dave Chinner
2012-03-29 12:23 ` [PATCH 1/8] xfs: check for buffer errors before waiting Dave Chinner
2012-03-29 19:04 ` Mark Tinguely
2012-03-29 21:10 ` Dave Chinner
2012-03-29 21:48 ` Mark Tinguely
2012-03-29 22:07 ` Dave Chinner
2012-03-29 19:12 ` Christoph Hellwig
2012-03-29 21:17 ` Dave Chinner
2012-03-29 12:23 ` [PATCH 2/8] xfs: fix incorrect b_offset initialisation Dave Chinner
2012-03-29 19:13 ` Christoph Hellwig
2012-03-29 20:43 ` Mark Tinguely [this message]
2012-03-29 12:23 ` [PATCH 3/8] xfs: use kmem_zone_zalloc for buffers Dave Chinner
2012-03-29 19:14 ` Christoph Hellwig
2012-03-29 20:45 ` Mark Tinguely
2012-03-29 12:23 ` [PATCH 4/8] xfs: clean up buffer get/read call API Dave Chinner
2012-03-30 19:12 ` Mark Tinguely
2012-03-29 12:23 ` [PATCH 5/8] xfs: kill b_file_offset Dave Chinner
2012-03-30 19:12 ` Mark Tinguely
2012-03-29 12:23 ` [PATCH 6/8] xfs: use blocks for counting length of buffers Dave Chinner
2012-03-29 19:16 ` Christoph Hellwig
2012-03-30 19:13 ` Mark Tinguely
2012-03-29 12:23 ` [PATCH 7/8] xfs: use blocks for storing the desired IO size Dave Chinner
2012-03-30 19:13 ` Mark Tinguely
2012-03-29 12:23 ` [PATCH 8/8] xfs: kill xfs_buf_btoc Dave Chinner
2012-03-29 19:18 ` Christoph Hellwig
2012-03-30 19:13 ` Mark Tinguely
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