Re: The INN/mmap bug

From: Chris Mason (mason@suse.com)
Date: Mon Sep 18 2000 - 08:29:39 EST


--On 09/18/00 09:16:22 -0400 Alexander Viro <viro@math.psu.edu> wrote:

>
>
> On Mon, 18 Sep 2000, Chris Mason wrote:
>
>> ReiserFS depends on the buffer head up to date flag being correct when it
>> is sent to get_block. When unpacking the tail, we have to know if the
>> packed data on disk should be copied over the data in the page.
>
> ??? Details, please. What the hell are you doing with buffer-heads for a
> piece of data that can be completely unaligned?
>

When reiserfs_get_block is called on the packed data (with create == 1), we
unpack it to a full block, so the generic functions can handle
dirties/writes from then on. If the data in the page cache isn't up to
date, we need to copy the packed data into the page cache so it doesn't get
lost in the conversion.

This isn't for writing directly to the tail, I'm only doing that in
writepage, where I always overwrite the tail data with page data.

-chris

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