Adding upstream version 14.2.21.upstream/14.2.21upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1525 insertions, 0 deletions

diff --git a/src/crush/builder.c b/src/crush/builder.c
new file mode 100644
index 00000000..68dfcb69
--- /dev/null
+++ b/src/crush/builder.c
@@ -0,0 +1,1525 @@
+#include <string.h>
+#include <math.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <assert.h>
+#include <errno.h>
+
+#include "crush/crush.h"
+#include "builder.h"
+
+#define dprintk(args...) /* printf(args) */
+
+#define BUG_ON(x) assert(!(x))
+
+struct crush_map *crush_create()
+{
+	struct crush_map *m;
+	m = malloc(sizeof(*m));
+        if (!m)
+                return NULL;
+	memset(m, 0, sizeof(*m));
+
+	set_optimal_crush_map(m);
+	return m;
+}
+
+/*
+ * finalize should be called _after_ all buckets are added to the map.
+ */
+void crush_finalize(struct crush_map *map)
+{
+	int b;
+	__u32 i;
+
+	/* Calculate the needed working space while we do other
+	   finalization tasks. */
+	map->working_size = sizeof(struct crush_work);
+	/* Space for the array of pointers to per-bucket workspace */
+	map->working_size += map->max_buckets *
+		sizeof(struct crush_work_bucket *);
+
+	/* calc max_devices */
+	map->max_devices = 0;
+	for (b=0; b<map->max_buckets; b++) {
+		if (map->buckets[b] == 0)
+			continue;
+		for (i=0; i<map->buckets[b]->size; i++)
+			if (map->buckets[b]->items[i] >= map->max_devices)
+				map->max_devices = map->buckets[b]->items[i] + 1;
+
+		switch (map->buckets[b]->alg) {
+		default:
+			/* The base case, permutation variables and
+			   the pointer to the permutation array. */
+			map->working_size += sizeof(struct crush_work_bucket);
+			break;
+		}
+		/* Every bucket has a permutation array. */
+		map->working_size += map->buckets[b]->size * sizeof(__u32);
+	}
+}
+
+
+
+/** rules **/
+
+int crush_add_rule(struct crush_map *map, struct crush_rule *rule, int ruleno)
+{
+	__u32 r;
+
+	if (ruleno < 0) {
+		for (r=0; r < map->max_rules; r++)
+			if (map->rules[r] == 0)
+				break;
+		assert(r < CRUSH_MAX_RULES);
+	}
+	else
+		r = ruleno;
+
+	if (r >= map->max_rules) {
+		/* expand array */
+		int oldsize;
+		void *_realloc = NULL;
+		if (map->max_rules +1 > CRUSH_MAX_RULES)
+			return -ENOSPC;
+		oldsize = map->max_rules;
+		map->max_rules = r+1;
+		if ((_realloc = realloc(map->rules, map->max_rules * sizeof(map->rules[0]))) == NULL) {
+			return -ENOMEM; 
+		} else {
+			map->rules = _realloc;
+		} 
+		memset(map->rules + oldsize, 0, (map->max_rules-oldsize) * sizeof(map->rules[0]));
+	}
+
+	/* add it */
+	map->rules[r] = rule;
+	return r;
+}
+
+struct crush_rule *crush_make_rule(int len, int ruleset, int type, int minsize, int maxsize)
+{
+	struct crush_rule *rule;
+	rule = malloc(crush_rule_size(len));
+        if (!rule)
+                return NULL;
+	rule->len = len;
+	rule->mask.ruleset = ruleset;
+	rule->mask.type = type;
+	rule->mask.min_size = minsize;
+	rule->mask.max_size = maxsize;
+	return rule;
+}
+
+/*
+ * be careful; this doesn't verify that the buffer you allocated is big enough!
+ */
+void crush_rule_set_step(struct crush_rule *rule, int n, int op, int arg1, int arg2)
+{
+	assert((__u32)n < rule->len);
+	rule->steps[n].op = op;
+	rule->steps[n].arg1 = arg1;
+	rule->steps[n].arg2 = arg2;
+}
+
+
+/** buckets **/
+int crush_get_next_bucket_id(struct crush_map *map)
+{
+	int pos;
+	for (pos=0; pos < map->max_buckets; pos++)
+		if (map->buckets[pos] == 0)
+			break;
+	return -1 - pos;
+}
+
+
+int crush_add_bucket(struct crush_map *map,
+		     int id,
+		     struct crush_bucket *bucket,
+		     int *idout)
+{
+	int pos;
+
+	/* find a bucket id */
+	if (id == 0)
+		id = crush_get_next_bucket_id(map);
+	pos = -1 - id;
+
+	while (pos >= map->max_buckets) {
+		/* expand array */
+		int oldsize = map->max_buckets;
+		if (map->max_buckets)
+			map->max_buckets *= 2;
+		else
+			map->max_buckets = 8;
+		void *_realloc = NULL;
+		if ((_realloc = realloc(map->buckets, map->max_buckets * sizeof(map->buckets[0]))) == NULL) {
+			return -ENOMEM; 
+		} else {
+			map->buckets = _realloc;
+		}
+		memset(map->buckets + oldsize, 0, (map->max_buckets-oldsize) * sizeof(map->buckets[0]));
+	}
+
+	if (map->buckets[pos] != 0) {
+		return -EEXIST;
+	}
+
+        /* add it */
+	bucket->id = id;
+	map->buckets[pos] = bucket;
+
+	if (idout) *idout = id;
+	return 0;
+}
+
+int crush_remove_bucket(struct crush_map *map, struct crush_bucket *bucket)
+{
+	int pos = -1 - bucket->id;
+       assert(pos < map->max_buckets);
+	map->buckets[pos] = NULL;
+	crush_destroy_bucket(bucket);
+	return 0;
+}
+
+
+/* uniform bucket */
+
+struct crush_bucket_uniform *
+crush_make_uniform_bucket(int hash, int type, int size,
+			  int *items,
+			  int item_weight)
+{
+	int i;
+	struct crush_bucket_uniform *bucket;
+
+	bucket = malloc(sizeof(*bucket));
+        if (!bucket)
+                return NULL;
+	memset(bucket, 0, sizeof(*bucket));
+	bucket->h.alg = CRUSH_BUCKET_UNIFORM;
+	bucket->h.hash = hash;
+	bucket->h.type = type;
+	bucket->h.size = size;
+
+	if (crush_multiplication_is_unsafe(size, item_weight))
+                goto err;
+
+	bucket->h.weight = size * item_weight;
+	bucket->item_weight = item_weight;
+	bucket->h.items = malloc(sizeof(__s32)*size);
+
+        if (!bucket->h.items)
+                goto err;
+
+	for (i=0; i<size; i++)
+		bucket->h.items[i] = items[i];
+
+	return bucket;
+err:
+        free(bucket->h.items);
+        free(bucket);
+        return NULL;
+}
+
+
+/* list bucket */
+
+struct crush_bucket_list*
+crush_make_list_bucket(int hash, int type, int size,
+		       int *items,
+		       int *weights)
+{
+	int i;
+	int w;
+	struct crush_bucket_list *bucket;
+
+	bucket = malloc(sizeof(*bucket));
+        if (!bucket)
+                return NULL;
+	memset(bucket, 0, sizeof(*bucket));
+	bucket->h.alg = CRUSH_BUCKET_LIST;
+	bucket->h.hash = hash;
+	bucket->h.type = type;
+	bucket->h.size = size;
+
+	bucket->h.items = malloc(sizeof(__s32)*size);
+        if (!bucket->h.items)
+                goto err;
+
+
+        bucket->item_weights = malloc(sizeof(__u32)*size);
+        if (!bucket->item_weights)
+                goto err;
+	bucket->sum_weights = malloc(sizeof(__u32)*size);
+        if (!bucket->sum_weights)
+                goto err;
+	w = 0;
+	for (i=0; i<size; i++) {
+		bucket->h.items[i] = items[i];
+		bucket->item_weights[i] = weights[i];
+
+		if (crush_addition_is_unsafe(w, weights[i]))
+                        goto err;
+
+		w += weights[i];
+		bucket->sum_weights[i] = w;
+		/*dprintk("pos %d item %d weight %d sum %d\n",
+		  i, items[i], weights[i], bucket->sum_weights[i]);*/
+	}
+
+	bucket->h.weight = w;
+
+	return bucket;
+err:
+        free(bucket->sum_weights);
+        free(bucket->item_weights);
+        free(bucket->h.items);
+        free(bucket);
+        return NULL;
+}
+
+
+/* tree bucket */
+
+static int height(int n) {
+	int h = 0;
+	while ((n & 1) == 0) {
+		h++;
+		n = n >> 1;
+	}
+	return h;
+}
+static int on_right(int n, int h) {
+	return n & (1 << (h+1));
+}
+static int parent(int n)
+{
+	int h = height(n);
+	if (on_right(n, h))
+		return n - (1<<h);
+	else
+		return n + (1<<h);
+}
+
+static int calc_depth(int size)
+{
+	if (size == 0) {
+		return 0;
+	}
+
+	int depth = 1;
+	int t = size - 1;
+	while (t) {
+		t = t >> 1;
+		depth++;
+	}
+	return depth;
+}
+
+struct crush_bucket_tree*
+crush_make_tree_bucket(int hash, int type, int size,
+		       int *items,    /* in leaf order */
+		       int *weights)
+{
+	struct crush_bucket_tree *bucket;
+	int depth;
+	int node;
+	int i, j;
+
+	bucket = malloc(sizeof(*bucket));
+        if (!bucket)
+                return NULL;
+	memset(bucket, 0, sizeof(*bucket));
+	bucket->h.alg = CRUSH_BUCKET_TREE;
+	bucket->h.hash = hash;
+	bucket->h.type = type;
+	bucket->h.size = size;
+
+	if (size == 0) {
+		bucket->h.items = NULL;
+		bucket->h.weight = 0;
+		bucket->node_weights = NULL;
+		bucket->num_nodes = 0;
+		/* printf("size 0 depth 0 nodes 0\n"); */
+		return bucket;
+	}
+
+	bucket->h.items = malloc(sizeof(__s32)*size);
+        if (!bucket->h.items)
+                goto err;
+
+	/* calc tree depth */
+	depth = calc_depth(size);
+	bucket->num_nodes = 1 << depth;
+	dprintk("size %d depth %d nodes %d\n", size, depth, bucket->num_nodes);
+
+        bucket->node_weights = malloc(sizeof(__u32)*bucket->num_nodes);
+        if (!bucket->node_weights)
+                goto err;
+
+	memset(bucket->h.items, 0, sizeof(__s32)*bucket->h.size);
+	memset(bucket->node_weights, 0, sizeof(__u32)*bucket->num_nodes);
+
+	for (i=0; i<size; i++) {
+		bucket->h.items[i] = items[i];
+		node = crush_calc_tree_node(i);
+		dprintk("item %d node %d weight %d\n", i, node, weights[i]);
+		bucket->node_weights[node] = weights[i];
+
+		if (crush_addition_is_unsafe(bucket->h.weight, weights[i]))
+                        goto err;
+
+		bucket->h.weight += weights[i];
+		for (j=1; j<depth; j++) {
+			node = parent(node);
+
+                        if (crush_addition_is_unsafe(bucket->node_weights[node], weights[i]))
+                                goto err;
+
+			bucket->node_weights[node] += weights[i];
+			dprintk(" node %d weight %d\n", node, bucket->node_weights[node]);
+		}
+	}
+	BUG_ON(bucket->node_weights[bucket->num_nodes/2] != bucket->h.weight);
+
+	return bucket;
+err:
+        free(bucket->node_weights);
+        free(bucket->h.items);
+        free(bucket);
+        return NULL;
+}
+
+
+
+/* straw bucket */
+
+/*
+ * this code was written 8 years ago.  i have a vague recollection of
+ * drawing boxes underneath bars of different lengths, where the bar
+ * length represented the probability/weight, and that there was some
+ * trial and error involved in arriving at this implementation.
+ * however, reading the code now after all this time, the intuition
+ * that motivated is lost on me.  lame.  my only excuse is that I now
+ * know that the approach is fundamentally flawed and am not
+ * particularly motivated to reconstruct the flawed reasoning.
+ *
+ * as best as i can remember, the idea is: sort the weights, and start
+ * with the smallest.  arbitrarily scale it at 1.0 (16-bit fixed
+ * point).  look at the next larger weight, and calculate the scaling
+ * factor for that straw based on the relative difference in weight so
+ * far.  what's not clear to me now is why we are looking at wnext
+ * (the delta to the next bigger weight) for all remaining weights,
+ * and slicing things horizontally instead of considering just the
+ * next item or set of items.  or why pow() is used the way it is.
+ *
+ * note that the original version 1 of this function made special
+ * accommodation for the case where straw lengths were identical.  this
+ * is also flawed in a non-obvious way; version 2 drops the special
+ * handling and appears to work just as well.
+ *
+ * moral of the story: if you do something clever, write down why it
+ * works.
+ */
+int crush_calc_straw(struct crush_map *map, struct crush_bucket_straw *bucket)
+{
+	int *reverse;
+	int i, j, k;
+	double straw, wbelow, lastw, wnext, pbelow;
+	int numleft;
+	int size = bucket->h.size;
+	__u32 *weights = bucket->item_weights;
+
+	/* reverse sort by weight (simple insertion sort) */
+	reverse = malloc(sizeof(int) * size);
+        if (!reverse)
+                return -ENOMEM;
+	if (size)
+		reverse[0] = 0;
+	for (i=1; i<size; i++) {
+		for (j=0; j<i; j++) {
+			if (weights[i] < weights[reverse[j]]) {
+				/* insert here */
+				for (k=i; k>j; k--)
+					reverse[k] = reverse[k-1];
+				reverse[j] = i;
+				break;
+			}
+		}
+		if (j == i)
+			reverse[i] = i;
+	}
+
+	numleft = size;
+	straw = 1.0;
+	wbelow = 0;
+	lastw = 0;
+
+	i=0;
+	while (i < size) {
+		if (map->straw_calc_version == 0) {
+			/* zero weight items get 0 length straws! */
+			if (weights[reverse[i]] == 0) {
+				bucket->straws[reverse[i]] = 0;
+				i++;
+				continue;
+			}
+
+			/* set this item's straw */
+			bucket->straws[reverse[i]] = straw * 0x10000;
+			dprintk("item %d at %d weight %d straw %d (%lf)\n",
+				bucket->h.items[reverse[i]],
+				reverse[i], weights[reverse[i]],
+				bucket->straws[reverse[i]], straw);
+			i++;
+			if (i == size)
+				break;
+
+			/* same weight as previous? */
+			if (weights[reverse[i]] == weights[reverse[i-1]]) {
+				dprintk("same as previous\n");
+				continue;
+			}
+
+			/* adjust straw for next guy */
+			wbelow += ((double)weights[reverse[i-1]] - lastw) *
+				numleft;
+			for (j=i; j<size; j++)
+				if (weights[reverse[j]] == weights[reverse[i]])
+					numleft--;
+				else
+					break;
+			wnext = numleft * (weights[reverse[i]] -
+					   weights[reverse[i-1]]);
+			pbelow = wbelow / (wbelow + wnext);
+			dprintk("wbelow %lf  wnext %lf  pbelow %lf  numleft %d\n",
+				wbelow, wnext, pbelow, numleft);
+
+			straw *= pow((double)1.0 / pbelow, (double)1.0 /
+				     (double)numleft);
+
+			lastw = weights[reverse[i-1]];
+		} else if (map->straw_calc_version >= 1) {
+			/* zero weight items get 0 length straws! */
+			if (weights[reverse[i]] == 0) {
+				bucket->straws[reverse[i]] = 0;
+				i++;
+				numleft--;
+				continue;
+			}
+
+			/* set this item's straw */
+			bucket->straws[reverse[i]] = straw * 0x10000;
+			dprintk("item %d at %d weight %d straw %d (%lf)\n",
+				bucket->h.items[reverse[i]],
+				reverse[i], weights[reverse[i]],
+				bucket->straws[reverse[i]], straw);
+			i++;
+			if (i == size)
+				break;
+
+			/* adjust straw for next guy */
+			wbelow += ((double)weights[reverse[i-1]] - lastw) *
+				numleft;
+			numleft--;
+			wnext = numleft * (weights[reverse[i]] -
+					   weights[reverse[i-1]]);
+			pbelow = wbelow / (wbelow + wnext);
+			dprintk("wbelow %lf  wnext %lf  pbelow %lf  numleft %d\n",
+				wbelow, wnext, pbelow, numleft);
+
+			straw *= pow((double)1.0 / pbelow, (double)1.0 /
+				     (double)numleft);
+
+			lastw = weights[reverse[i-1]];
+		}
+	}
+
+	free(reverse);
+	return 0;
+}
+
+struct crush_bucket_straw *
+crush_make_straw_bucket(struct crush_map *map,
+			int hash,
+			int type,
+			int size,
+			int *items,
+			int *weights)
+{
+	struct crush_bucket_straw *bucket;
+	int i;
+
+	bucket = malloc(sizeof(*bucket));
+        if (!bucket)
+                return NULL;
+	memset(bucket, 0, sizeof(*bucket));
+	bucket->h.alg = CRUSH_BUCKET_STRAW;
+	bucket->h.hash = hash;
+	bucket->h.type = type;
+	bucket->h.size = size;
+
+        bucket->h.items = malloc(sizeof(__s32)*size);
+        if (!bucket->h.items)
+                goto err;
+	bucket->item_weights = malloc(sizeof(__u32)*size);
+        if (!bucket->item_weights)
+                goto err;
+        bucket->straws = malloc(sizeof(__u32)*size);
+        if (!bucket->straws)
+                goto err;
+
+        bucket->h.weight = 0;
+	for (i=0; i<size; i++) {
+		bucket->h.items[i] = items[i];
+		bucket->h.weight += weights[i];
+		bucket->item_weights[i] = weights[i];
+	}
+
+        if (crush_calc_straw(map, bucket) < 0)
+                goto err;
+
+	return bucket;
+err:
+        free(bucket->straws);
+        free(bucket->item_weights);
+        free(bucket->h.items);
+        free(bucket);
+        return NULL;
+}
+
+struct crush_bucket_straw2 *
+crush_make_straw2_bucket(struct crush_map *map,
+			 int hash,
+			 int type,
+			 int size,
+			 int *items,
+			 int *weights)
+{
+	struct crush_bucket_straw2 *bucket;
+	int i;
+
+	bucket = malloc(sizeof(*bucket));
+        if (!bucket)
+                return NULL;
+	memset(bucket, 0, sizeof(*bucket));
+	bucket->h.alg = CRUSH_BUCKET_STRAW2;
+	bucket->h.hash = hash;
+	bucket->h.type = type;
+	bucket->h.size = size;
+
+        bucket->h.items = malloc(sizeof(__s32)*size);
+        if (!bucket->h.items)
+                goto err;
+	bucket->item_weights = malloc(sizeof(__u32)*size);
+        if (!bucket->item_weights)
+                goto err;
+
+        bucket->h.weight = 0;
+	for (i=0; i<size; i++) {
+		bucket->h.items[i] = items[i];
+		bucket->h.weight += weights[i];
+		bucket->item_weights[i] = weights[i];
+	}
+
+	return bucket;
+err:
+        free(bucket->item_weights);
+        free(bucket->h.items);
+        free(bucket);
+        return NULL;
+}
+
+
+
+struct crush_bucket*
+crush_make_bucket(struct crush_map *map,
+		  int alg, int hash, int type, int size,
+		  int *items,
+		  int *weights)
+{
+	int item_weight;
+
+	switch (alg) {
+	case CRUSH_BUCKET_UNIFORM:
+		if (size && weights)
+			item_weight = weights[0];
+		else
+			item_weight = 0;
+		return (struct crush_bucket *)crush_make_uniform_bucket(hash, type, size, items, item_weight);
+
+	case CRUSH_BUCKET_LIST:
+		return (struct crush_bucket *)crush_make_list_bucket(hash, type, size, items, weights);
+
+	case CRUSH_BUCKET_TREE:
+		return (struct crush_bucket *)crush_make_tree_bucket(hash, type, size, items, weights);
+
+	case CRUSH_BUCKET_STRAW:
+		return (struct crush_bucket *)crush_make_straw_bucket(map, hash, type, size, items, weights);
+	case CRUSH_BUCKET_STRAW2:
+		return (struct crush_bucket *)crush_make_straw2_bucket(map, hash, type, size, items, weights);
+	}
+	return 0;
+}
+
+
+/************************************************/
+
+int crush_add_uniform_bucket_item(struct crush_bucket_uniform *bucket, int item, int weight)
+{
+        int newsize = bucket->h.size + 1;
+	void *_realloc = NULL;
+
+	/* In such situation 'CRUSH_BUCKET_UNIFORM', the weight
+	   provided for the item should be the same as
+	   bucket->item_weight defined with 'crush_make_bucket'. This
+	   assumption is enforced by the return value which is always
+	   0. */
+	if (bucket->item_weight != weight) {
+	  return -EINVAL;
+	}
+
+	if ((_realloc = realloc(bucket->h.items, sizeof(__s32)*newsize)) == NULL) {
+		return -ENOMEM;
+	} else {
+		bucket->h.items = _realloc;
+	}
+
+	bucket->h.items[newsize-1] = item;
+
+        if (crush_addition_is_unsafe(bucket->h.weight, weight))
+                return -ERANGE;
+
+        bucket->h.weight += weight;
+        bucket->h.size++;
+
+        return 0;
+}
+
+int crush_add_list_bucket_item(struct crush_bucket_list *bucket, int item, int weight)
+{
+        int newsize = bucket->h.size + 1;
+	void *_realloc = NULL;
+
+	if ((_realloc = realloc(bucket->h.items, sizeof(__s32)*newsize)) == NULL) {
+		return -ENOMEM;
+	} else {
+		bucket->h.items = _realloc;
+	}
+	if ((_realloc = realloc(bucket->item_weights, sizeof(__u32)*newsize)) == NULL) {
+		return -ENOMEM;
+	} else {
+		bucket->item_weights = _realloc;
+	}
+	if ((_realloc = realloc(bucket->sum_weights, sizeof(__u32)*newsize)) == NULL) {
+		return -ENOMEM;
+	} else {
+		bucket->sum_weights = _realloc;
+	}
+	
+	bucket->h.items[newsize-1] = item;
+	bucket->item_weights[newsize-1] = weight;
+	if (newsize > 1) {
+
+                if (crush_addition_is_unsafe(bucket->sum_weights[newsize-2], weight))
+                        return -ERANGE;
+
+                bucket->sum_weights[newsize-1] = bucket->sum_weights[newsize-2] + weight;
+	}
+
+        else {
+                bucket->sum_weights[newsize-1] = weight;
+        }
+
+	bucket->h.weight += weight;
+	bucket->h.size++;
+	return 0;
+}
+
+int crush_add_tree_bucket_item(struct crush_bucket_tree *bucket, int item, int weight)
+{
+	int newsize = bucket->h.size + 1;
+	int depth = calc_depth(newsize);;
+	int node;
+	int j;
+	void *_realloc = NULL;
+
+	bucket->num_nodes = 1 << depth;
+
+	if ((_realloc = realloc(bucket->h.items, sizeof(__s32)*newsize)) == NULL) {
+		return -ENOMEM;
+	} else {
+		bucket->h.items = _realloc;
+	}
+	if ((_realloc = realloc(bucket->node_weights, sizeof(__u32)*bucket->num_nodes)) == NULL) {
+		return -ENOMEM;
+	} else {
+		bucket->node_weights = _realloc;
+	}
+
+	node = crush_calc_tree_node(newsize-1);
+	bucket->node_weights[node] = weight;
+
+	/* if the depth increase, we need to initialize the new root node's weight before add bucket item */
+	int root = bucket->num_nodes/2;
+	if (depth >= 2 && (node - 1) == root) {
+		/* if the new item is the first node in right sub tree, so
+		* the root node initial weight is left sub tree's weight
+		*/
+		bucket->node_weights[root] = bucket->node_weights[root/2];
+	}
+
+	for (j=1; j<depth; j++) {
+		node = parent(node);
+
+                if (crush_addition_is_unsafe(bucket->node_weights[node], weight))
+                        return -ERANGE;
+
+		bucket->node_weights[node] += weight;
+                dprintk(" node %d weight %d\n", node, bucket->node_weights[node]);
+	}
+
+
+	if (crush_addition_is_unsafe(bucket->h.weight, weight))
+                return -ERANGE;
+	
+	bucket->h.items[newsize-1] = item;
+        bucket->h.weight += weight;
+        bucket->h.size++;
+
+	return 0;
+}
+
+int crush_add_straw_bucket_item(struct crush_map *map,
+				struct crush_bucket_straw *bucket,
+				int item, int weight)
+{
+	int newsize = bucket->h.size + 1;
+
+	void *_realloc = NULL;
+
+	if ((_realloc = realloc(bucket->h.items, sizeof(__s32)*newsize)) == NULL) {
+		return -ENOMEM;
+	} else {
+		bucket->h.items = _realloc;
+	}
+	if ((_realloc = realloc(bucket->item_weights, sizeof(__u32)*newsize)) == NULL) {
+		return -ENOMEM;
+	} else {
+		bucket->item_weights = _realloc;
+	}
+	if ((_realloc = realloc(bucket->straws, sizeof(__u32)*newsize)) == NULL) {
+		return -ENOMEM;
+	} else {
+		bucket->straws = _realloc;
+	}
+
+	bucket->h.items[newsize-1] = item;
+	bucket->item_weights[newsize-1] = weight;
+
+	if (crush_addition_is_unsafe(bucket->h.weight, weight))
+                return -ERANGE;
+
+	bucket->h.weight += weight;
+	bucket->h.size++;
+	
+	return crush_calc_straw(map, bucket);
+}
+
+int crush_add_straw2_bucket_item(struct crush_map *map,
+				 struct crush_bucket_straw2 *bucket,
+				 int item, int weight)
+{
+	int newsize = bucket->h.size + 1;
+
+	void *_realloc = NULL;
+
+	if ((_realloc = realloc(bucket->h.items, sizeof(__s32)*newsize)) == NULL) {
+		return -ENOMEM;
+	} else {
+		bucket->h.items = _realloc;
+	}
+	if ((_realloc = realloc(bucket->item_weights, sizeof(__u32)*newsize)) == NULL) {
+		return -ENOMEM;
+	} else {
+		bucket->item_weights = _realloc;
+	}
+
+	bucket->h.items[newsize-1] = item;
+	bucket->item_weights[newsize-1] = weight;
+
+	if (crush_addition_is_unsafe(bucket->h.weight, weight))
+                return -ERANGE;
+
+	bucket->h.weight += weight;
+	bucket->h.size++;
+
+	return 0;
+}
+
+int crush_bucket_add_item(struct crush_map *map,
+			  struct crush_bucket *b, int item, int weight)
+{
+	switch (b->alg) {
+	case CRUSH_BUCKET_UNIFORM:
+		return crush_add_uniform_bucket_item((struct crush_bucket_uniform *)b, item, weight);
+	case CRUSH_BUCKET_LIST:
+		return crush_add_list_bucket_item((struct crush_bucket_list *)b, item, weight);
+	case CRUSH_BUCKET_TREE:
+		return crush_add_tree_bucket_item((struct crush_bucket_tree *)b, item, weight);
+	case CRUSH_BUCKET_STRAW:
+		return crush_add_straw_bucket_item(map, (struct crush_bucket_straw *)b, item, weight);
+	case CRUSH_BUCKET_STRAW2:
+		return crush_add_straw2_bucket_item(map, (struct crush_bucket_straw2 *)b, item, weight);
+	default:
+		return -1;
+	}
+}
+
+/************************************************/
+
+int crush_remove_uniform_bucket_item(struct crush_bucket_uniform *bucket, int item)
+{
+	unsigned i, j;
+	int newsize;
+	void *_realloc = NULL;
+	
+	for (i = 0; i < bucket->h.size; i++)
+		if (bucket->h.items[i] == item)
+			break;
+	if (i == bucket->h.size)
+		return -ENOENT;
+
+	for (j = i; j < bucket->h.size; j++)
+		bucket->h.items[j] = bucket->h.items[j+1];
+	newsize = --bucket->h.size;
+	if (bucket->item_weight < bucket->h.weight)
+		bucket->h.weight -= bucket->item_weight;
+	else
+		bucket->h.weight = 0;
+
+	if ((_realloc = realloc(bucket->h.items, sizeof(__s32)*newsize)) == NULL) {
+		return -ENOMEM;
+	} else {
+		bucket->h.items = _realloc;
+	}
+	return 0;
+}
+
+int crush_remove_list_bucket_item(struct crush_bucket_list *bucket, int item)
+{
+	unsigned i, j;
+	int newsize;
+	unsigned weight;
+
+	for (i = 0; i < bucket->h.size; i++)
+		if (bucket->h.items[i] == item)
+			break;
+	if (i == bucket->h.size)
+		return -ENOENT;
+
+	weight = bucket->item_weights[i];
+	for (j = i; j < bucket->h.size; j++) {
+		bucket->h.items[j] = bucket->h.items[j+1];
+		bucket->item_weights[j] = bucket->item_weights[j+1];
+		bucket->sum_weights[j] = bucket->sum_weights[j+1] - weight;
+	}
+	if (weight < bucket->h.weight)
+		bucket->h.weight -= weight;
+	else
+		bucket->h.weight = 0;
+	newsize = --bucket->h.size;
+	
+	void *_realloc = NULL;
+
+	if ((_realloc = realloc(bucket->h.items, sizeof(__s32)*newsize)) == NULL) {
+		return -ENOMEM;
+	} else {
+		bucket->h.items = _realloc;
+	}
+	if ((_realloc = realloc(bucket->item_weights, sizeof(__u32)*newsize)) == NULL) {
+		return -ENOMEM;
+	} else {
+		bucket->item_weights = _realloc;
+	}
+	if ((_realloc = realloc(bucket->sum_weights, sizeof(__u32)*newsize)) == NULL) {
+		return -ENOMEM;
+	} else {
+		bucket->sum_weights = _realloc;
+	}
+	return 0;
+}
+
+int crush_remove_tree_bucket_item(struct crush_bucket_tree *bucket, int item)
+{
+	unsigned i;
+	unsigned newsize;
+
+	for (i = 0; i < bucket->h.size; i++) {
+		int node;
+		unsigned weight;
+		int j;
+		int depth = calc_depth(bucket->h.size);
+
+		if (bucket->h.items[i] != item)
+			continue;
+
+		bucket->h.items[i] = 0;
+		node = crush_calc_tree_node(i);
+		weight = bucket->node_weights[node];
+		bucket->node_weights[node] = 0;
+
+		for (j = 1; j < depth; j++) {
+			node = parent(node);
+			bucket->node_weights[node] -= weight;
+			dprintk(" node %d weight %d\n", node, bucket->node_weights[node]);
+		}
+		if (weight < bucket->h.weight)
+			bucket->h.weight -= weight;
+		else
+			bucket->h.weight = 0;
+		break;
+	}
+	if (i == bucket->h.size)
+		return -ENOENT;
+
+	newsize = bucket->h.size;
+	while (newsize > 0) {
+		int node = crush_calc_tree_node(newsize - 1);
+		if (bucket->node_weights[node])
+			break;
+		--newsize;
+	}
+
+	if (newsize != bucket->h.size) {
+		int olddepth, newdepth;
+
+		void *_realloc = NULL;
+
+		if ((_realloc = realloc(bucket->h.items, sizeof(__s32)*newsize)) == NULL) {
+			return -ENOMEM;
+		} else {
+			bucket->h.items = _realloc;
+		}
+
+		olddepth = calc_depth(bucket->h.size);
+		newdepth = calc_depth(newsize);
+		if (olddepth != newdepth) {
+			bucket->num_nodes = 1 << newdepth;
+			if ((_realloc = realloc(bucket->node_weights, 
+						sizeof(__u32)*bucket->num_nodes)) == NULL) {
+				return -ENOMEM;
+			} else {
+				bucket->node_weights = _realloc;
+			}
+		}
+
+		bucket->h.size = newsize;
+	}
+	return 0;
+}
+
+int crush_remove_straw_bucket_item(struct crush_map *map,
+				   struct crush_bucket_straw *bucket, int item)
+{
+	int newsize = bucket->h.size - 1;
+	unsigned i, j;
+
+	for (i = 0; i < bucket->h.size; i++) {
+		if (bucket->h.items[i] == item) {
+			if (bucket->item_weights[i] < bucket->h.weight)
+				bucket->h.weight -= bucket->item_weights[i];
+			else
+				bucket->h.weight = 0;
+			for (j = i; j < bucket->h.size - 1; j++) {
+				bucket->h.items[j] = bucket->h.items[j+1];
+				bucket->item_weights[j] = bucket->item_weights[j+1];
+			}
+			break;
+		}
+	}
+	if (i == bucket->h.size)
+		return -ENOENT;
+	bucket->h.size--;
+	if (bucket->h.size == 0) {
+		/* don't bother reallocating */
+		return 0;
+	}
+	void *_realloc = NULL;
+
+	if ((_realloc = realloc(bucket->h.items, sizeof(__s32)*newsize)) == NULL) {
+		return -ENOMEM;
+	} else {
+		bucket->h.items = _realloc;
+	}
+	if ((_realloc = realloc(bucket->item_weights, sizeof(__u32)*newsize)) == NULL) {
+		return -ENOMEM;
+	} else {
+		bucket->item_weights = _realloc;
+	}
+	if ((_realloc = realloc(bucket->straws, sizeof(__u32)*newsize)) == NULL) {
+		return -ENOMEM;
+	} else {
+		bucket->straws = _realloc;
+	}
+
+	return crush_calc_straw(map, bucket);
+}
+
+int crush_remove_straw2_bucket_item(struct crush_map *map,
+				    struct crush_bucket_straw2 *bucket, int item)
+{
+	int newsize = bucket->h.size - 1;
+	unsigned i, j;
+
+	for (i = 0; i < bucket->h.size; i++) {
+		if (bucket->h.items[i] == item) {
+			if (bucket->item_weights[i] < bucket->h.weight)
+				bucket->h.weight -= bucket->item_weights[i];
+			else
+				bucket->h.weight = 0;
+			for (j = i; j < bucket->h.size - 1; j++) {
+				bucket->h.items[j] = bucket->h.items[j+1];
+				bucket->item_weights[j] = bucket->item_weights[j+1];
+			}
+			break;
+		}
+	}
+	if (i == bucket->h.size)
+		return -ENOENT;
+
+	bucket->h.size--;
+	if (!newsize) {
+		/* don't bother reallocating a 0-length array. */
+		return 0;
+	}
+
+	void *_realloc = NULL;
+
+	if ((_realloc = realloc(bucket->h.items, sizeof(__s32)*newsize)) == NULL) {
+		return -ENOMEM;
+	} else {
+		bucket->h.items = _realloc;
+	}
+	if ((_realloc = realloc(bucket->item_weights, sizeof(__u32)*newsize)) == NULL) {
+		return -ENOMEM;
+	} else {
+		bucket->item_weights = _realloc;
+	}
+
+	return 0;
+}
+
+int crush_bucket_remove_item(struct crush_map *map, struct crush_bucket *b, int item)
+{
+	switch (b->alg) {
+	case CRUSH_BUCKET_UNIFORM:
+		return crush_remove_uniform_bucket_item((struct crush_bucket_uniform *)b, item);
+	case CRUSH_BUCKET_LIST:
+		return crush_remove_list_bucket_item((struct crush_bucket_list *)b, item);
+	case CRUSH_BUCKET_TREE:
+		return crush_remove_tree_bucket_item((struct crush_bucket_tree *)b, item);
+	case CRUSH_BUCKET_STRAW:
+		return crush_remove_straw_bucket_item(map, (struct crush_bucket_straw *)b, item);
+	case CRUSH_BUCKET_STRAW2:
+		return crush_remove_straw2_bucket_item(map, (struct crush_bucket_straw2 *)b, item);
+	default:
+		return -1;
+	}
+}
+
+
+/************************************************/
+
+int crush_adjust_uniform_bucket_item_weight(struct crush_bucket_uniform *bucket, int item, int weight)
+{
+	int diff = (weight - bucket->item_weight) * bucket->h.size;
+
+	bucket->item_weight = weight;
+	bucket->h.weight = bucket->item_weight * bucket->h.size;
+
+	return diff;
+}
+
+int crush_adjust_list_bucket_item_weight(struct crush_bucket_list *bucket, int item, int weight)
+{
+	int diff;
+	unsigned i, j;
+
+	for (i = 0; i < bucket->h.size; i++) {
+		if (bucket->h.items[i] == item)
+			break;
+	}
+	if (i == bucket->h.size)
+		return 0;
+
+	diff = weight - bucket->item_weights[i];
+	bucket->item_weights[i] = weight;
+	bucket->h.weight += diff;
+
+	for (j = i; j < bucket->h.size; j++)
+		bucket->sum_weights[j] += diff;
+
+	return diff;
+}
+
+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;
+}
+
+int crush_adjust_straw_bucket_item_weight(struct crush_map *map,
+					  struct crush_bucket_straw *bucket,
+					  int item, int weight)
+{
+	unsigned idx;
+	int diff;
+        int r;
+
+	for (idx = 0; idx < bucket->h.size; idx++)
+		if (bucket->h.items[idx] == item)
+			break;
+	if (idx == bucket->h.size)
+		return 0;
+
+	diff = weight - bucket->item_weights[idx];
+	bucket->item_weights[idx] = weight;
+	bucket->h.weight += diff;
+
+	r = crush_calc_straw(map, bucket);
+        if (r < 0)
+                return r;
+
+	return diff;
+}
+
+int crush_adjust_straw2_bucket_item_weight(struct crush_map *map,
+					   struct crush_bucket_straw2 *bucket,
+					   int item, int weight)
+{
+	unsigned idx;
+	int diff;
+
+	for (idx = 0; idx < bucket->h.size; idx++)
+		if (bucket->h.items[idx] == item)
+			break;
+	if (idx == bucket->h.size)
+		return 0;
+
+	diff = weight - bucket->item_weights[idx];
+	bucket->item_weights[idx] = weight;
+	bucket->h.weight += diff;
+
+	return diff;
+}
+
+int crush_bucket_adjust_item_weight(struct crush_map *map,
+				    struct crush_bucket *b,
+				    int item, int weight)
+{
+	switch (b->alg) {
+	case CRUSH_BUCKET_UNIFORM:
+		return crush_adjust_uniform_bucket_item_weight((struct crush_bucket_uniform *)b,
+							     item, weight);
+	case CRUSH_BUCKET_LIST:
+		return crush_adjust_list_bucket_item_weight((struct crush_bucket_list *)b,
+							    item, weight);
+	case CRUSH_BUCKET_TREE:
+		return crush_adjust_tree_bucket_item_weight((struct crush_bucket_tree *)b,
+							    item, weight);
+	case CRUSH_BUCKET_STRAW:
+		return crush_adjust_straw_bucket_item_weight(map,
+							     (struct crush_bucket_straw *)b,
+							     item, weight);
+	case CRUSH_BUCKET_STRAW2:
+		return crush_adjust_straw2_bucket_item_weight(map,
+							      (struct crush_bucket_straw2 *)b,
+							     item, weight);
+	default:
+		return -1;
+	}
+}
+
+/************************************************/
+
+static int crush_reweight_uniform_bucket(struct crush_map *map, struct crush_bucket_uniform *bucket)
+{
+	unsigned i;
+	unsigned sum = 0, n = 0, leaves = 0;
+
+	for (i = 0; i < bucket->h.size; i++) {
+		int id = bucket->h.items[i];
+		if (id < 0) {
+			struct crush_bucket *c = map->buckets[-1-id];
+			crush_reweight_bucket(map, c);
+
+			if (crush_addition_is_unsafe(sum, c->weight))
+                                return -ERANGE;
+
+			sum += c->weight;
+			n++;
+		} else {
+			leaves++;
+		}
+	}
+
+	if (n > leaves)
+		bucket->item_weight = sum / n;  // more bucket children than leaves, average!
+	bucket->h.weight = bucket->item_weight * bucket->h.size;
+
+	return 0;
+}
+
+static int crush_reweight_list_bucket(struct crush_map *map, struct crush_bucket_list *bucket)
+{
+	unsigned i;
+
+	bucket->h.weight = 0;
+	for (i = 0; i < bucket->h.size; i++) {
+		int id = bucket->h.items[i];
+		if (id < 0) {
+			struct crush_bucket *c = map->buckets[-1-id];
+			crush_reweight_bucket(map, c);
+			bucket->item_weights[i] = c->weight;
+		}
+
+		if (crush_addition_is_unsafe(bucket->h.weight, bucket->item_weights[i]))
+                        return -ERANGE;
+
+		bucket->h.weight += bucket->item_weights[i];
+	}
+
+	return 0;
+}
+
+static int crush_reweight_tree_bucket(struct crush_map *map, struct crush_bucket_tree *bucket)
+{
+	unsigned i;
+
+	bucket->h.weight = 0;
+	for (i = 0; i < bucket->h.size; i++) {
+		int node = crush_calc_tree_node(i);
+		int id = bucket->h.items[i];
+		if (id < 0) {
+			struct crush_bucket *c = map->buckets[-1-id];
+			crush_reweight_bucket(map, c);
+			bucket->node_weights[node] = c->weight;
+		}
+
+		if (crush_addition_is_unsafe(bucket->h.weight, bucket->node_weights[node]))
+                        return -ERANGE;
+
+		bucket->h.weight += bucket->node_weights[node];
+
+
+	}
+
+	return 0;
+}
+
+static int crush_reweight_straw_bucket(struct crush_map *map, struct crush_bucket_straw *bucket)
+{
+	unsigned i;
+
+	bucket->h.weight = 0;
+	for (i = 0; i < bucket->h.size; i++) {
+		int id = bucket->h.items[i];
+		if (id < 0) {
+			struct crush_bucket *c = map->buckets[-1-id];
+			crush_reweight_bucket(map, c);
+			bucket->item_weights[i] = c->weight;
+		}
+
+                if (crush_addition_is_unsafe(bucket->h.weight, bucket->item_weights[i]))
+                        return -ERANGE;
+
+                bucket->h.weight += bucket->item_weights[i];
+	}
+	crush_calc_straw(map, bucket);
+
+	return 0;
+}
+
+static int crush_reweight_straw2_bucket(struct crush_map *map, struct crush_bucket_straw2 *bucket)
+{
+	unsigned i;
+
+	bucket->h.weight = 0;
+	for (i = 0; i < bucket->h.size; i++) {
+		int id = bucket->h.items[i];
+		if (id < 0) {
+			struct crush_bucket *c = map->buckets[-1-id];
+			crush_reweight_bucket(map, c);
+			bucket->item_weights[i] = c->weight;
+		}
+
+                if (crush_addition_is_unsafe(bucket->h.weight, bucket->item_weights[i]))
+                        return -ERANGE;
+
+                bucket->h.weight += bucket->item_weights[i];
+	}
+
+	return 0;
+}
+
+int crush_reweight_bucket(struct crush_map *map, struct crush_bucket *b)
+{
+	switch (b->alg) {
+	case CRUSH_BUCKET_UNIFORM:
+		return crush_reweight_uniform_bucket(map, (struct crush_bucket_uniform *)b);
+	case CRUSH_BUCKET_LIST:
+		return crush_reweight_list_bucket(map, (struct crush_bucket_list *)b);
+	case CRUSH_BUCKET_TREE:
+		return crush_reweight_tree_bucket(map, (struct crush_bucket_tree *)b);
+	case CRUSH_BUCKET_STRAW:
+		return crush_reweight_straw_bucket(map, (struct crush_bucket_straw *)b);
+	case CRUSH_BUCKET_STRAW2:
+		return crush_reweight_straw2_bucket(map, (struct crush_bucket_straw2 *)b);
+	default:
+		return -1;
+	}
+}
+
+struct crush_choose_arg *crush_make_choose_args(struct crush_map *map, int num_positions)
+{
+  int b;
+  int sum_bucket_size = 0;
+  int bucket_count = 0;
+  for (b = 0; b < map->max_buckets; b++) {
+    if (map->buckets[b] == 0)
+      continue;
+    sum_bucket_size += map->buckets[b]->size;
+    bucket_count++;
+  }
+  dprintk("sum_bucket_size %d max_buckets %d bucket_count %d\n",
+          sum_bucket_size, map->max_buckets, bucket_count);
+  int size = (sizeof(struct crush_choose_arg) * map->max_buckets +
+              sizeof(struct crush_weight_set) * bucket_count * num_positions +
+              sizeof(__u32) * sum_bucket_size * num_positions + // weights
+              sizeof(__s32) * sum_bucket_size); // ids
+  char *space = malloc(size);
+  struct crush_choose_arg *arg = (struct crush_choose_arg *)space;
+  struct crush_weight_set *weight_set = (struct crush_weight_set *)(arg + map->max_buckets);
+  __u32 *weights = (__u32 *)(weight_set + bucket_count * num_positions);
+  char *weight_set_ends __attribute__((unused)) = (char*)weights;
+  __s32 *ids = (__s32 *)(weights + sum_bucket_size * num_positions);
+  char *weights_end __attribute__((unused)) = (char *)ids;
+  char *ids_end __attribute__((unused)) = (char *)(ids + sum_bucket_size);
+  BUG_ON(space + size != ids_end);
+  for (b = 0; b < map->max_buckets; b++) {
+    if (map->buckets[b] == 0) {
+      memset(&arg[b], '\0', sizeof(struct crush_choose_arg));
+      continue;
+    }
+    struct crush_bucket_straw2 *bucket = (struct crush_bucket_straw2 *)map->buckets[b];
+
+    int position;
+    for (position = 0; position < num_positions; position++) {
+      memcpy(weights, bucket->item_weights, sizeof(__u32) * bucket->h.size);
+      weight_set[position].weights = weights;
+      weight_set[position].size = bucket->h.size;
+      dprintk("moving weight %d bytes forward\n", (int)((weights + bucket->h.size) - weights));
+      weights += bucket->h.size;
+    }
+    arg[b].weight_set = weight_set;
+    arg[b].weight_set_positions = num_positions;
+    weight_set += position;
+
+    memcpy(ids, bucket->h.items, sizeof(__s32) * bucket->h.size);
+    arg[b].ids = ids;
+    arg[b].ids_size = bucket->h.size;
+    ids += bucket->h.size;
+  }
+  BUG_ON((char*)weight_set_ends != (char*)weight_set);
+  BUG_ON((char*)weights_end != (char*)weights);
+  BUG_ON((char*)ids != (char*)ids_end);
+  return arg;
+}
+
+void crush_destroy_choose_args(struct crush_choose_arg *args)
+{
+  free(args);
+}
+
+/***************************/
+
+/* methods to check for safe arithmetic operations */
+
+int crush_addition_is_unsafe(__u32 a, __u32 b)
+{
+	if ((((__u32)(-1)) - b) < a)
+		return 1;
+	else
+		return 0;
+}
+
+int crush_multiplication_is_unsafe(__u32  a, __u32 b)
+{
+	/* prevent division by zero */
+        if (!a)
+                return 0;
+	if (!b)
+		return 1;
+	if ((((__u32)(-1)) / b) < a)
+		return 1;
+	else
+		return 0;
+}
+
+/***************************/
+
+/* methods to configure crush_map */
+
+void set_legacy_crush_map(struct crush_map *map) {
+  /* initialize legacy tunable values */
+  map->choose_local_tries = 2;
+  map->choose_local_fallback_tries = 5;
+  map->choose_total_tries = 19;
+  map->chooseleaf_descend_once = 0;
+  map->chooseleaf_vary_r = 0;
+  map->chooseleaf_stable = 0;
+  map->straw_calc_version = 0;
+
+  // by default, use legacy types, and also exclude tree,
+  // since it was buggy.
+  map->allowed_bucket_algs = CRUSH_LEGACY_ALLOWED_BUCKET_ALGS;
+}
+
+void set_optimal_crush_map(struct crush_map *map) {
+  map->choose_local_tries = 0;
+  map->choose_local_fallback_tries = 0;
+  map->choose_total_tries = 50;
+  map->chooseleaf_descend_once = 1;
+  map->chooseleaf_vary_r = 1;
+  map->chooseleaf_stable = 1;
+  map->allowed_bucket_algs = (
+    (1 << CRUSH_BUCKET_UNIFORM) |
+    (1 << CRUSH_BUCKET_LIST) |
+    (1 << CRUSH_BUCKET_STRAW) |
+    (1 << CRUSH_BUCKET_STRAW2));
+}