From aabf591007a83dc6520329bce929570115849286 Mon Sep 17 00:00:00 2001 From: Fam Zheng Date: Wed, 5 Apr 2017 14:44:24 +0800 Subject: block: Quiesce old aio context during bdrv_set_aio_context The fact that the bs->aio_context is changing can confuse the dataplane iothread, because of the now fine granularity aio context lock. bdrv_drain should rather be a bdrv_drained_begin/end pair, but since bs->aio_context is changing, we can just use aio_disable_external and bdrv_parent_drained_begin. Reported-by: Ed Swierk Signed-off-by: Fam Zheng Acked-by: Stefan Hajnoczi Reviewed-by: Stefan Hajnoczi Reviewed-by: Kevin Wolf --- block.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'block.c') diff --git a/block.c b/block.c index b8a30115e1..a995a8ec00 100644 --- a/block.c +++ b/block.c @@ -4396,11 +4396,12 @@ void bdrv_attach_aio_context(BlockDriverState *bs, void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context) { - AioContext *ctx; + AioContext *ctx = bdrv_get_aio_context(bs); + aio_disable_external(ctx); + bdrv_parent_drained_begin(bs); bdrv_drain(bs); /* ensure there are no in-flight requests */ - ctx = bdrv_get_aio_context(bs); while (aio_poll(ctx, false)) { /* wait for all bottom halves to execute */ } @@ -4412,6 +4413,8 @@ void bdrv_set_aio_context(BlockDriverState *bs, AioContext *new_context) */ aio_context_acquire(new_context); bdrv_attach_aio_context(bs, new_context); + bdrv_parent_drained_end(bs); + aio_enable_external(ctx); aio_context_release(new_context); } -- cgit v1.2.1