On 11/04/2017 00:04, Stefan Hajnoczi wrote:
> On Mon, Apr 10, 2017 at 10:26:34AM +0800, Fam Zheng wrote:
>> v3: Use bdrv_parent_drained_begin/end. [Kevin]
>> Do it before releasing new_context. [Stefan]
>>
>> Fam Zheng (2):
>> block: Make bdrv_parent_drained_begin/end public
>> block: Quiesce old aio context during bdrv_set_aio_context
>>
>> block.c | 7 +++++--
>> block/io.c | 4 ++--
>> include/block/block.h | 16 ++++++++++++++++
>> 3 files changed, 23 insertions(+), 4 deletions(-)
>
> Thanks, applied to my block tree for 2.10:
> https://github.com/stefanha/qemu/commits/block
>
> If you'd like this in a stable release please CC qemu-stable.
Stefan, can you squash this documentation patch in please?
diff --git a/block.c b/block.c
index 3b20a29..cb1c5c9 100644
--- a/block.c
+++ b/block.c
@@ -4392,6 +4392,18 @@ void bdrv_set_aio_context(BlockDriverState *bs,
AioContext *new_context)
{
AioContext *ctx = bdrv_get_aio_context(bs);
+ /* FIXME: This is the same as bdrv_drained_begin, only done
+ * manually. At the end of this function, aio_enable_external
+ * must be done on ctx, not on new_context, so we cannot call
+ * bdrv_drained_end there. And because bs->quiesce_counter will
+ * not be decreased there, we have to "explode" bdrv_drained_begin
+ * here too.
+ *
+ * Once aio_disable_external and aio_enable_external are replaced
+ * by BlockBackend device ops (called by .drained_begin/end
+ * BdrvChildRole callbacks), this can be replaced by a simple
+ * bdrv_drained_begin/end pair.
+ */
aio_disable_external(ctx);
bdrv_parent_drained_begin(bs);
bdrv_drain(bs); /* ensure there are no in-flight requests */
Thanks,
Paolo
