Re: [PATCH 1/3] direct-io: add a hook for the fs to provide its own bio merging check function

[Miao Xie <miaox@cn.fujitsu.com>]

On 	wed, 17 Nov 2010 20:24:39 -0500, Chris Mason wrote:
> Excerpts from Miao Xie's message of 2010-11-17 20:18:18 -0500:
>>>> Right thats the idea, if we can't span chunks/stripes we should be doing that
>>>> limiting in our get_blocks call and that way we don't have to screw with the
>>>> generic direct io stuff too much.  Thanks,
>>>
>>> In this case we're adding complexity to the O_DIRECT mapping code, when
>>> we really should be adding it to the btrfs submit bio hook.  It can
>>> easily break up the bio into smaller units, which will leave us with a
>>> smaller number of get_blocks calls overall.
>>>
>>> I'm working that out now.
>>
>> Do you mean you are fixing this bug now?
>
> I started on it this afternoon, but lost network due to high winds here.
> So, I didn't make any real progress.
>
> If you'd like to fix this in the btrfs direct-io bio submit call you're
> welcome to continue working on it.
>
> The idea is to just clone and split up the bio, which will keep us from
> filling up fs/direct-io.c w/btrfs rules and allow us to take fewer
> trips into the get_blocks call.

Ok, I'll do it.

Thanks
Miao