From 36fe13317bfc3414745528c6c08cea2904ca49ec Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Tue, 17 May 2016 14:51:55 +0200 Subject: block: Fix reconfiguring graph with drained nodes When changing the BlockDriverState that a BdrvChild points to while the node is currently drained, we must call the .drained_end() parent callback. Conversely, when this means attaching a new node that is already drained, we need to call .drained_begin(). bdrv_root_attach_child() takes now an opaque parameter, which is needed because the callbacks must also be called if we're attaching a new child to the BlockBackend when the root node is already drained, and they need a way to identify the BlockBackend. Previously, child->opaque was set too late and the callbacks would still see it as NULL. Signed-off-by: Kevin Wolf Reviewed-by: Eric Blake Reviewed-by: Fam Zheng --- block/block-backend.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'block/block-backend.c') diff --git a/block/block-backend.c b/block/block-backend.c index 4e8298b291..14e528ea82 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -161,8 +161,7 @@ BlockBackend *blk_new_open(const char *filename, const char *reference, } blk_set_enable_write_cache(blk, true); - blk->root = bdrv_root_attach_child(bs, "root", &child_root); - blk->root->opaque = blk; + blk->root = bdrv_root_attach_child(bs, "root", &child_root, blk); return blk; } @@ -481,8 +480,7 @@ void blk_remove_bs(BlockBackend *blk) void blk_insert_bs(BlockBackend *blk, BlockDriverState *bs) { bdrv_ref(bs); - blk->root = bdrv_root_attach_child(bs, "root", &child_root); - blk->root->opaque = blk; + blk->root = bdrv_root_attach_child(bs, "root", &child_root, blk); notifier_list_notify(&blk->insert_bs_notifiers, blk); if (blk->public.throttle_state) { @@ -1676,6 +1674,9 @@ static void blk_root_drained_begin(BdrvChild *child) { BlockBackend *blk = child->opaque; + /* Note that blk->root may not be accessible here yet if we are just + * attaching to a BlockDriverState that is drained. Use child instead. */ + if (blk->public.io_limits_disabled++ == 0) { throttle_group_restart_blk(blk); } -- cgit v1.2.3