Ceph » RADOS

From: ZhuRongze <zrz4ceph@gmail.com>
Date: Wed, Feb 15, 2012 at 5:51 AM
Subject: I found some problem in CRUSH code
To: ceph-devel <ceph-devel@vger.kernel.org>

Hi,

The function crush_adjust_tree_bucket_item_weight in
ceph-0.41/src/crush/builder.c seem to ?have a bug. The argument weight
is no use, because it is assigned .
--------------------------------------------------------------------
int crush_adjust_tree_bucket_item_weight(struct crush_bucket_tree
*bucket, int item, int weight)
{
? ?int diff;
? ?int node;
? ?unsigned i, j;
? ?unsigned depth = calc_depth(bucket->h.size);

? ?for (i = 0; i < bucket->h.size; i++) {
? ? ? ?if (bucket->h.items[i] == item)
? ? ? ? ? ?break;
? ?}
? ?if (i == bucket->h.size)
? ? ? ?return 0;

? ?node = crush_calc_tree_node(i);
? ?diff = weight = bucket->node_weights[node];
? ?bucket->node_weights[node] = weight;
? ?bucket->h.weight += diff;

? ?for (j=1; j<depth; j++) {
? ? ? ?node = parent(node);
? ? ? ?bucket->node_weights[node] += diff;
? ?}

? ?return diff;

those = should be -, as with the straw bucket code.

1- make a cli test that breaks on current code
2- fix the bug