On Wed, Dec 5, 2018 at 2:17 AM Dongsheng Yang
<dongsheng.yang@xxxxxxxxxxxx> wrote:
>
>
>
> On 12/04/2018 10:28 PM, Ilya Dryomov wrote:
> > On Mon, Dec 3, 2018 at 1:51 PM Dongsheng Yang
> > <dongsheng.yang@xxxxxxxxxxxx> wrote:
> >> When we want to add some prefix to the bio data, such as journal header,
> >> we don't want to copy it from bio into a new larger memory. Instead, we need
> >> a prefix page and suffix page to store the header and footer in bio_iter.
> >>
> >> Signed-off-by: Dongsheng Yang <dongsheng.yang@xxxxxxxxxxxx>
> ...
> >> }
> >> #endif /* CONFIG_BLOCK */
> > Have you looked at message data items (ceph_msg_data) for this?
> > A message can have multiple data items, each of different type (BIO,
> > PAGES, etc) and with its own iterator. The messenger will exhaust them
> > in order, so you can create a message with three data items: prefix
> > (type PAGES), data (type BIO), suffix (type PAGES).
> Yes, that was my first idea, but I found the framework is not
> enough to my case. And as I need to use bio only in my case,
What was the problem?
Thanks,
Ilya
