Exemplo n.º 1
0
int dm_btree_del(struct dm_btree_info *info, dm_block_t root)
{
	int r;
	struct del_stack *s;

	s = kmalloc(sizeof(*s), GFP_NOIO);
	if (!s)
		return -ENOMEM;
	s->tm = info->tm;
	s->top = -1;

	r = push_frame(s, root, 0);
	if (r)
		goto out;

	while (unprocessed_frames(s)) {
		uint32_t flags;
		struct frame *f;
		dm_block_t b;

		r = top_frame(s, &f);
		if (r)
			goto out;

		if (f->current_child >= f->nr_children) {
			pop_frame(s);
			continue;
		}

		flags = le32_to_cpu(f->n->header.flags);
		if (flags & INTERNAL_NODE) {
			b = value64(f->n, f->current_child);
			f->current_child++;
			r = push_frame(s, b, f->level);
			if (r)
				goto out;

		} else if (is_internal_level(info, f)) {
			b = value64(f->n, f->current_child);
			f->current_child++;
			r = push_frame(s, b, f->level + 1);
			if (r)
				goto out;

		} else {
			if (info->value_type.dec) {
				unsigned i;

				for (i = 0; i < f->nr_children; i++)
					info->value_type.dec(info->value_type.context,
							     value_ptr(f->n, i));
			}
			f->current_child = f->nr_children;
		}
	}

out:
	kfree(s);
	return r;
}
Exemplo n.º 2
0
static int push_frame(struct del_stack *s, dm_block_t b, unsigned level)
{
	int r;
	uint32_t ref_count;

	if (s->top >= MAX_SPINE_DEPTH - 1) {
		DMERR("btree deletion stack out of memory");
		return -ENOMEM;
	}

	r = dm_tm_ref(s->tm, b, &ref_count);
	if (r)
		return r;

	if (ref_count > 1)
		/*
		 * This is a shared node, so we can just decrement it's
		 * reference counter and leave the children.
		 */
		dm_tm_dec(s->tm, b);

	else {
		uint32_t flags;
		struct frame *f = s->spine + ++s->top;

		r = dm_tm_read_lock(s->tm, b, &btree_node_validator, &f->b);
		if (r) {
			s->top--;
			return r;
		}

		f->n = dm_block_data(f->b);
		f->level = level;
		f->nr_children = le32_to_cpu(f->n->header.nr_entries);
		f->current_child = 0;

		flags = le32_to_cpu(f->n->header.flags);
		if (flags & INTERNAL_NODE || is_internal_level(s->info, f))
			prefetch_children(s, f);
	}

	return 0;
}