Re: [PATCH v2 04/20] block/block-copy: More explicit call_state

[Vladimir Sementsov-Ogievskiy]

17.07.2020 16:45, Max Reitz wrote:
> On 01.06.20 20:11, Vladimir Sementsov-Ogievskiy wrote:
> > Refactor common path to use BlockCopyCallState pointer as parameter, to
> > prepare it for use in asynchronous block-copy (at least, we'll need to
> > run block-copy in a coroutine, passing the whole parameters as one
> > pointer).
> >
> > Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> > ---
> >   block/block-copy.c | 51 ++++++++++++++++++++++++++++++++++------------
> >   1 file changed, 38 insertions(+), 13 deletions(-)
> >
> > diff --git a/block/block-copy.c b/block/block-copy.c
> > index 43a018d190..75882a094c 100644
> > --- a/block/block-copy.c
> > +++ b/block/block-copy.c
>
> [...]
>
> > @@ -646,16 +653,16 @@ out:
> >    * it means that some I/O operation failed in context of _this_ block_copy 
> > call,
> >    * not some parallel operation.
> >    */
> > -int coroutine_fn block_copy(BlockCopyState *s, int64_t offset, int64_t bytes,
> > -                            bool *error_is_read)
> > +static int coroutine_fn block_copy_common(BlockCopyCallState *call_state)
> >   {
> >       int ret;
> >   
> >       do {
> > -        ret = block_copy_dirty_clusters(s, offset, bytes, error_is_read);
> > +        ret = block_copy_dirty_clusters(call_state);
>
> It’s possible that much of this code will change in a future patch of
> this series, but as it is, it might be nice to make
> block_copy_dirty_clusters’s argument a const pointer so it’s clear that
> the call to block_copy_wait_one() below will use the original @offset
> and @bytes values.

Hm. I'm trying this, and it doesn't work:

block_copy_task_entry() wants to change call_state:

   t->call_state->failed = true;

> *shrug*
>
> Reviewed-by: Max Reitz <mreitz@redhat.com>
>
> >   
> >           if (ret == 0) {
> > -            ret = block_copy_wait_one(s, offset, bytes);
> > +            ret = block_copy_wait_one(call_state->s, call_state->offset,
> > +                                      call_state->bytes);
> >           }
> >   
> >           /*


--
Best regards,
Vladimir