Re: [PATCH 02/26] qcow2: remove incorrect coroutine_fn annotations

[Paolo Bonzini]

On 4/21/22 12:24, Stefan Hajnoczi wrote:
> > > -int coroutine_fn qcow2_flush_caches(BlockDriverState *bs)
> > > +int qcow2_flush_caches(BlockDriverState *bs)
> > >   {
> > >       int ret = qcow2_write_caches(bs);
> >
> > Both of these eventually hit qcow2_cache_write, which is not marked
> > coroutine, so these should not be either.
>
> coroutine_fn may call non-coroutine_fn, so this alone is not a reason
> for removing it from qcow2_write_caches().
>
> There must be a call chain where qcow2_write_caches() and
> qcow2_flush_caches() are is invoked from outside coroutine_fn.

The main problematic caller is qcow2_inactivate(), which calls these 
functions via qcow2_mark_clean().  Another one is 
update_ext_header_and_dir(), called by 
qcow2_store_persistent_dirty_bitmaps(), called by qcow2_inactivate().

Converting inactivate to run in coroutine context would help.

Paolo