We don't want new requests from guest, so block the operation around the nested poll.
Signed-off-by: Fam Zheng <f...@redhat.com> --- block/io.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/block/io.c b/block/io.c index 1ce62c4..d369de3 100644 --- a/block/io.c +++ b/block/io.c @@ -289,9 +289,15 @@ static bool bdrv_drain_one(BlockDriverState *bs) */ void bdrv_drain(BlockDriverState *bs) { + Error *blocker = NULL; + + error_setg(&blocker, "bdrv_drain in progress"); + bdrv_op_block(bs, BLOCK_OP_TYPE_DEVICE_IO, blocker); while (bdrv_drain_one(bs)) { /* Keep iterating */ } + bdrv_op_unblock(bs, BLOCK_OP_TYPE_DEVICE_IO, blocker); + error_free(blocker); } /* @@ -311,6 +317,9 @@ void bdrv_drain_all(void) /* Always run first iteration so any pending completion BHs run */ bool busy = true; BlockDriverState *bs = NULL; + Error *blocker = NULL; + + error_setg(&blocker, "bdrv_drain_all in progress"); while ((bs = bdrv_next(bs))) { AioContext *aio_context = bdrv_get_aio_context(bs); @@ -319,6 +328,7 @@ void bdrv_drain_all(void) if (bs->job) { block_job_pause(bs->job); } + bdrv_op_block(bs, BLOCK_OP_TYPE_DEVICE_IO, blocker); aio_context_release(aio_context); } @@ -343,8 +353,10 @@ void bdrv_drain_all(void) if (bs->job) { block_job_resume(bs->job); } + bdrv_op_unblock(bs, BLOCK_OP_TYPE_DEVICE_IO, blocker); aio_context_release(aio_context); } + error_free(blocker); } /** -- 1.9.3