block: move drain outside of quorum_del_child()
The quorum_del_child() callback runs under the graph lock, so it is
not allowed to drain. It is only called as the .bdrv_del_child()
callback, which is only called in the bdrv_del_child() function, which
also runs under the graph lock.
The bdrv_del_child() function is called by qmp_x_blockdev_change().
A drained section was already introduced there by commit "block: move
drain out of quorum_add_child()".
This finally finishes moving out the drain to places that are not
under the graph lock started in "block: move draining out of
bdrv_change_aio_context() and mark GRAPH_RDLOCK".
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
Message-ID: <20250530151125.955508-17-f.ebner@proxmox.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block.c b/block.c
index 15a8ccb..bfd4340 100644
--- a/block.c
+++ b/block.c
@@ -8276,6 +8276,8 @@
/*
* Hot remove a BDS's child. Used in combination with bdrv_add_child, so the
* user can take a child offline when it is broken and take a new child online.
+ *
+ * All block nodes must be drained.
*/
void bdrv_del_child(BlockDriverState *parent_bs, BdrvChild *child, Error **errp)
{
diff --git a/block/quorum.c b/block/quorum.c
index 81407a3..cc3bc5f 100644
--- a/block/quorum.c
+++ b/block/quorum.c
@@ -1147,9 +1147,7 @@
(s->num_children - i - 1) * sizeof(BdrvChild *));
s->children = g_renew(BdrvChild *, s->children, --s->num_children);
- bdrv_drain_all_begin();
bdrv_unref_child(bs, child);
- bdrv_drain_all_end();
quorum_refresh_flags(bs);
}
diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h
index f9e742f..925a3e7 100644
--- a/include/block/block_int-common.h
+++ b/include/block/block_int-common.h
@@ -406,6 +406,13 @@
void GRAPH_WRLOCK_PTR (*bdrv_add_child)(
BlockDriverState *parent, BlockDriverState *child, Error **errp);
+ /**
+ * Hot remove a BDS's child. Used in combination with bdrv_add_child, so the
+ * user can take a child offline when it is broken and take a new child
+ * online.
+ *
+ * All block nodes must be drained.
+ */
void GRAPH_WRLOCK_PTR (*bdrv_del_child)(
BlockDriverState *parent, BdrvChild *child, Error **errp);
