/* this prevents anyone from attaching or migrating to this blkcg */
wb_blkcg_offline(blkcg);
- /* put the base cgwb reference allowing step 2 to be triggered */
- blkcg_cgwb_put(blkcg);
+ /* put the base online pin allowing step 2 to be triggered */
+ blkcg_unpin_online(blkcg);
}
/**
}
spin_lock_init(&blkcg->lock);
+ refcount_set(&blkcg->online_pin, 1);
INIT_RADIX_TREE(&blkcg->blkg_tree, GFP_NOWAIT | __GFP_NOWARN);
INIT_HLIST_HEAD(&blkcg->blkg_list);
#ifdef CONFIG_CGROUP_WRITEBACK
INIT_LIST_HEAD(&blkcg->cgwb_list);
- refcount_set(&blkcg->cgwb_refcnt, 1);
#endif
list_add_tail(&blkcg->all_blkcgs_node, &all_blkcgs);
return ret;
}
+static int blkcg_css_online(struct cgroup_subsys_state *css)
+{
+ struct blkcg *blkcg = css_to_blkcg(css);
+ struct blkcg *parent = blkcg_parent(blkcg);
+
+ /*
+ * blkcg_pin_online() is used to delay blkcg offline so that blkgs
+ * don't go offline while cgwbs are still active on them. Pin the
+ * parent so that offline always happens towards the root.
+ */
+ if (parent)
+ blkcg_pin_online(parent);
+ return 0;
+}
+
/**
* blkcg_init_queue - initialize blkcg part of request queue
* @q: request_queue to initialize
struct cgroup_subsys io_cgrp_subsys = {
.css_alloc = blkcg_css_alloc,
+ .css_online = blkcg_css_online,
.css_offline = blkcg_css_offline,
.css_free = blkcg_css_free,
.can_attach = blkcg_can_attach,