Provide API for a node insertion to and removal from a backing chain. Suggested-by: Max Reitz <mre...@redhat.com> Signed-off-by: Andrey Shinkevich <andrey.shinkev...@virtuozzo.com> --- block.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++ include/block/block.h | 3 +++ 2 files changed, 52 insertions(+)
diff --git a/block.c b/block.c index 430edf7..502b483 100644 --- a/block.c +++ b/block.c @@ -4670,6 +4670,55 @@ static void bdrv_delete(BlockDriverState *bs) g_free(bs); } +BlockDriverState *bdrv_insert_node(BlockDriverState *bs, QDict *node_options, + int flags, Error **errp) +{ + BlockDriverState *new_node_bs; + Error *local_err = NULL; + + new_node_bs = bdrv_open(NULL, NULL, node_options, flags, errp); + if (new_node_bs == NULL) { + error_prepend(errp, "Could not create node: "); + return NULL; + } + + bdrv_drained_begin(bs); + bdrv_replace_node(bs, new_node_bs, &local_err); + bdrv_drained_end(bs); + + if (local_err) { + bdrv_unref(new_node_bs); + error_propagate(errp, local_err); + return NULL; + } + + return new_node_bs; +} + +void bdrv_remove_node(BlockDriverState *bs) +{ + BdrvChild *child; + BlockDriverState *inferior_bs; + + child = bdrv_filter_or_cow_child(bs); + if (!child) { + return; + } + inferior_bs = child->bs; + + /* Retain the BDS until we complete the graph change. */ + bdrv_ref(inferior_bs); + /* Hold a guest back from writing while permissions are being reset. */ + bdrv_drained_begin(inferior_bs); + /* Refresh permissions before the graph change. */ + bdrv_child_refresh_perms(bs, child, &error_abort); + bdrv_replace_node(bs, inferior_bs, &error_abort); + + bdrv_drained_end(inferior_bs); + bdrv_unref(inferior_bs); + bdrv_unref(bs); +} + /* * Run consistency checks on an image * diff --git a/include/block/block.h b/include/block/block.h index d16c401..ae7612f 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -350,6 +350,9 @@ void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top, Error **errp); void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to, Error **errp); +BlockDriverState *bdrv_insert_node(BlockDriverState *bs, QDict *node_options, + int flags, Error **errp); +void bdrv_remove_node(BlockDriverState *bs); int bdrv_parse_aio(const char *mode, int *flags); int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough); -- 1.8.3.1