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block: Fix reconfiguring graph with drained nodes

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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 <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
This commit is contained in:
Kevin Wolf 2016-05-17 14:51:55 +02:00
parent 6820643fdb
commit 36fe13317b
3 changed files with 22 additions and 10 deletions
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20
block.c
View file

@ -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);
}
if (new_bs) {
QLIST_INSERT_HEAD(&new_bs->parents, 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);
}
}
}
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;
}

9
block/block-backend.c
View file

@ -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);
}

3
include/block/block_int.h
View file

@ -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);