diff options
Diffstat (limited to 'block.c')
| -rw-r--r-- | block.c | 32 |
1 files changed, 31 insertions, 1 deletions
@@ -1095,7 +1095,7 @@ static BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs, return child; } -void bdrv_detach_child(BdrvChild *child) +static void bdrv_detach_child(BdrvChild *child) { QLIST_REMOVE(child, next); QLIST_REMOVE(child, next_parent); @@ -2232,6 +2232,36 @@ void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top) bdrv_unref(bs_new); } +void bdrv_replace_in_backing_chain(BlockDriverState *old, BlockDriverState *new) +{ + assert(!bdrv_requests_pending(old)); + assert(!bdrv_requests_pending(new)); + + bdrv_ref(old); + + if (old->blk) { + /* As long as these fields aren't in BlockBackend, but in the top-level + * BlockDriverState, it's not possible for a BDS to have two BBs. + * + * We really want to copy the fields from old to new, but we go for a + * swap instead so that pointers aren't duplicated and cause trouble. + * (Also, bdrv_swap() used to do the same.) */ + assert(!new->blk); + swap_feature_fields(old, new); + } + change_parent_backing_link(old, new); + + /* Change backing files if a previously independent node is added to the + * chain. For active commit, we replace top by its own (indirect) backing + * file and don't do anything here so we don't build a loop. */ + if (new->backing == NULL && !bdrv_chain_contains(backing_bs(old), new)) { + bdrv_set_backing_hd(new, backing_bs(old)); + bdrv_set_backing_hd(old, NULL); + } + + bdrv_unref(old); +} + static void bdrv_delete(BlockDriverState *bs) { assert(!bs->job); |