From 0f12264e7a41458179ad10276a7c33c72024861a Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Wed, 28 Mar 2018 18:29:18 +0200 Subject: block: Allow graph changes in bdrv_drain_all_begin/end sections bdrv_drain_all_*() used bdrv_next() to iterate over all root nodes and did a subtree drain for each of them. This works fine as long as the graph is static, but sadly, reality looks different. If the graph changes so that root nodes are added or removed, we would have to compensate for this. bdrv_next() returns each root node only once even if it's the root node for multiple BlockBackends or for a monitor-owned block driver tree, which would only complicate things. The much easier and more obviously correct way is to fundamentally change the way the functions work: Iterate over all BlockDriverStates, no matter who owns them, and drain them individually. Compensation is only necessary when a new BDS is created inside a drain_all section. Removal of a BDS doesn't require any action because it's gone afterwards anyway. Signed-off-by: Kevin Wolf --- include/block/block.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/block/block.h') diff --git a/include/block/block.h b/include/block/block.h index 836746e4e1..b1d6fdb97a 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -421,6 +421,7 @@ BlockDriverState *bdrv_lookup_bs(const char *device, Error **errp); bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base); BlockDriverState *bdrv_next_node(BlockDriverState *bs); +BlockDriverState *bdrv_next_all_states(BlockDriverState *bs); typedef struct BdrvNextIterator { enum { -- cgit v1.2.3-55-g7522