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

[Paolo Bonzini <pbonzini@redhat.com>]

On 4/27/22 14:36, Paolo Bonzini wrote:
> 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.

Or maybe not so much because bdrv_close also calls the same paths.

Paolo