From 36fe13317bfc3414745528c6c08cea2904ca49ec Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Tue, 17 May 2016 14:51:55 +0200 Subject: [PATCH] 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.c | 18 ++++++++++++++---- block/block-backend.c | 9 +++++---- include/block/block_int.h | 3 ++- 3 files changed, 21 insertions(+), 9 deletions(-) diff --git a/block.c b/block.c index 351344e408..598624f869 100644 --- a/block.c +++ b/block.c @@ -1155,24 +1155,33 @@ static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs) BlockDriverState *old_bs = child->bs; if (old_bs) { + if (old_bs->quiesce_counter && child->role->drained_end) { + child->role->drained_end(child); + } QLIST_REMOVE(child, next_parent); } + + child->bs = new_bs; + if (new_bs) { QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent); + if (new_bs->quiesce_counter && child->role->drained_begin) { + child->role->drained_begin(child); + } } - - child->bs = new_bs; } BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, const char *child_name, - const BdrvChildRole *child_role) + const BdrvChildRole *child_role, + void *opaque) { BdrvChild *child = g_new(BdrvChild, 1); *child = (BdrvChild) { .bs = NULL, .name = g_strdup(child_name), .role = child_role, + .opaque = opaque, }; bdrv_replace_child(child, child_bs); @@ -1185,7 +1194,8 @@ BdrvChild *bdrv_attach_child(BlockDriverState *parent_bs, const char *child_name, const BdrvChildRole *child_role) { - BdrvChild *child = bdrv_root_attach_child(child_bs, child_name, child_role); + BdrvChild *child = bdrv_root_attach_child(child_bs, child_name, child_role, + NULL); QLIST_INSERT_HEAD(&parent_bs->children, child, next); return child; } 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); } diff --git a/include/block/block_int.h b/include/block/block_int.h index b6f4755725..30a97178c8 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -719,7 +719,8 @@ void hmp_drive_add_node(Monitor *mon, const char *optstr); BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs, const char *child_name, - const BdrvChildRole *child_role); + const BdrvChildRole *child_role, + void *opaque); void bdrv_root_unref_child(BdrvChild *child); const char *bdrv_get_parent_name(const BlockDriverState *bs); -- 2.11.4.GIT