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-rw-r--r--kernel/net/ceph/crush/mapper.c927
1 files changed, 927 insertions, 0 deletions
diff --git a/kernel/net/ceph/crush/mapper.c b/kernel/net/ceph/crush/mapper.c
new file mode 100644
index 000000000..5b47736d2
--- /dev/null
+++ b/kernel/net/ceph/crush/mapper.c
@@ -0,0 +1,927 @@
+
+#ifdef __KERNEL__
+# include <linux/string.h>
+# include <linux/slab.h>
+# include <linux/bug.h>
+# include <linux/kernel.h>
+# ifndef dprintk
+# define dprintk(args...)
+# endif
+#else
+# include <string.h>
+# include <stdio.h>
+# include <stdlib.h>
+# include <assert.h>
+# define BUG_ON(x) assert(!(x))
+# define dprintk(args...) /* printf(args) */
+# define kmalloc(x, f) malloc(x)
+# define kfree(x) free(x)
+#endif
+
+#include <linux/crush/crush.h>
+#include <linux/crush/hash.h>
+#include "crush_ln_table.h"
+
+/*
+ * Implement the core CRUSH mapping algorithm.
+ */
+
+/**
+ * crush_find_rule - find a crush_rule id for a given ruleset, type, and size.
+ * @map: the crush_map
+ * @ruleset: the storage ruleset id (user defined)
+ * @type: storage ruleset type (user defined)
+ * @size: output set size
+ */
+int crush_find_rule(const struct crush_map *map, int ruleset, int type, int size)
+{
+ __u32 i;
+
+ for (i = 0; i < map->max_rules; i++) {
+ if (map->rules[i] &&
+ map->rules[i]->mask.ruleset == ruleset &&
+ map->rules[i]->mask.type == type &&
+ map->rules[i]->mask.min_size <= size &&
+ map->rules[i]->mask.max_size >= size)
+ return i;
+ }
+ return -1;
+}
+
+
+/*
+ * bucket choose methods
+ *
+ * For each bucket algorithm, we have a "choose" method that, given a
+ * crush input @x and replica position (usually, position in output set) @r,
+ * will produce an item in the bucket.
+ */
+
+/*
+ * Choose based on a random permutation of the bucket.
+ *
+ * We used to use some prime number arithmetic to do this, but it
+ * wasn't very random, and had some other bad behaviors. Instead, we
+ * calculate an actual random permutation of the bucket members.
+ * Since this is expensive, we optimize for the r=0 case, which
+ * captures the vast majority of calls.
+ */
+static int bucket_perm_choose(struct crush_bucket *bucket,
+ int x, int r)
+{
+ unsigned int pr = r % bucket->size;
+ unsigned int i, s;
+
+ /* start a new permutation if @x has changed */
+ if (bucket->perm_x != (__u32)x || bucket->perm_n == 0) {
+ dprintk("bucket %d new x=%d\n", bucket->id, x);
+ bucket->perm_x = x;
+
+ /* optimize common r=0 case */
+ if (pr == 0) {
+ s = crush_hash32_3(bucket->hash, x, bucket->id, 0) %
+ bucket->size;
+ bucket->perm[0] = s;
+ bucket->perm_n = 0xffff; /* magic value, see below */
+ goto out;
+ }
+
+ for (i = 0; i < bucket->size; i++)
+ bucket->perm[i] = i;
+ bucket->perm_n = 0;
+ } else if (bucket->perm_n == 0xffff) {
+ /* clean up after the r=0 case above */
+ for (i = 1; i < bucket->size; i++)
+ bucket->perm[i] = i;
+ bucket->perm[bucket->perm[0]] = 0;
+ bucket->perm_n = 1;
+ }
+
+ /* calculate permutation up to pr */
+ for (i = 0; i < bucket->perm_n; i++)
+ dprintk(" perm_choose have %d: %d\n", i, bucket->perm[i]);
+ while (bucket->perm_n <= pr) {
+ unsigned int p = bucket->perm_n;
+ /* no point in swapping the final entry */
+ if (p < bucket->size - 1) {
+ i = crush_hash32_3(bucket->hash, x, bucket->id, p) %
+ (bucket->size - p);
+ if (i) {
+ unsigned int t = bucket->perm[p + i];
+ bucket->perm[p + i] = bucket->perm[p];
+ bucket->perm[p] = t;
+ }
+ dprintk(" perm_choose swap %d with %d\n", p, p+i);
+ }
+ bucket->perm_n++;
+ }
+ for (i = 0; i < bucket->size; i++)
+ dprintk(" perm_choose %d: %d\n", i, bucket->perm[i]);
+
+ s = bucket->perm[pr];
+out:
+ dprintk(" perm_choose %d sz=%d x=%d r=%d (%d) s=%d\n", bucket->id,
+ bucket->size, x, r, pr, s);
+ return bucket->items[s];
+}
+
+/* uniform */
+static int bucket_uniform_choose(struct crush_bucket_uniform *bucket,
+ int x, int r)
+{
+ return bucket_perm_choose(&bucket->h, x, r);
+}
+
+/* list */
+static int bucket_list_choose(struct crush_bucket_list *bucket,
+ int x, int r)
+{
+ int i;
+
+ for (i = bucket->h.size-1; i >= 0; i--) {
+ __u64 w = crush_hash32_4(bucket->h.hash,x, bucket->h.items[i],
+ r, bucket->h.id);
+ w &= 0xffff;
+ dprintk("list_choose i=%d x=%d r=%d item %d weight %x "
+ "sw %x rand %llx",
+ i, x, r, bucket->h.items[i], bucket->item_weights[i],
+ bucket->sum_weights[i], w);
+ w *= bucket->sum_weights[i];
+ w = w >> 16;
+ /*dprintk(" scaled %llx\n", w);*/
+ if (w < bucket->item_weights[i])
+ return bucket->h.items[i];
+ }
+
+ dprintk("bad list sums for bucket %d\n", bucket->h.id);
+ return bucket->h.items[0];
+}
+
+
+/* (binary) tree */
+static int height(int n)
+{
+ int h = 0;
+ while ((n & 1) == 0) {
+ h++;
+ n = n >> 1;
+ }
+ return h;
+}
+
+static int left(int x)
+{
+ int h = height(x);
+ return x - (1 << (h-1));
+}
+
+static int right(int x)
+{
+ int h = height(x);
+ return x + (1 << (h-1));
+}
+
+static int terminal(int x)
+{
+ return x & 1;
+}
+
+static int bucket_tree_choose(struct crush_bucket_tree *bucket,
+ int x, int r)
+{
+ int n;
+ __u32 w;
+ __u64 t;
+
+ /* start at root */
+ n = bucket->num_nodes >> 1;
+
+ while (!terminal(n)) {
+ int l;
+ /* pick point in [0, w) */
+ w = bucket->node_weights[n];
+ t = (__u64)crush_hash32_4(bucket->h.hash, x, n, r,
+ bucket->h.id) * (__u64)w;
+ t = t >> 32;
+
+ /* descend to the left or right? */
+ l = left(n);
+ if (t < bucket->node_weights[l])
+ n = l;
+ else
+ n = right(n);
+ }
+
+ return bucket->h.items[n >> 1];
+}
+
+
+/* straw */
+
+static int bucket_straw_choose(struct crush_bucket_straw *bucket,
+ int x, int r)
+{
+ __u32 i;
+ int high = 0;
+ __u64 high_draw = 0;
+ __u64 draw;
+
+ for (i = 0; i < bucket->h.size; i++) {
+ draw = crush_hash32_3(bucket->h.hash, x, bucket->h.items[i], r);
+ draw &= 0xffff;
+ draw *= bucket->straws[i];
+ if (i == 0 || draw > high_draw) {
+ high = i;
+ high_draw = draw;
+ }
+ }
+ return bucket->h.items[high];
+}
+
+// compute 2^44*log2(input+1)
+uint64_t crush_ln(unsigned xin)
+{
+ unsigned x=xin, x1;
+ int iexpon, index1, index2;
+ uint64_t RH, LH, LL, xl64, result;
+
+ x++;
+
+ // normalize input
+ iexpon = 15;
+ while(!(x&0x18000)) { x<<=1; iexpon--; }
+
+ index1 = (x>>8)<<1;
+ // RH ~ 2^56/index1
+ RH = __RH_LH_tbl[index1 - 256];
+ // LH ~ 2^48 * log2(index1/256)
+ LH = __RH_LH_tbl[index1 + 1 - 256];
+
+ // RH*x ~ 2^48 * (2^15 + xf), xf<2^8
+ xl64 = (int64_t)x * RH;
+ xl64 >>= 48;
+ x1 = xl64;
+
+ result = iexpon;
+ result <<= (12 + 32);
+
+ index2 = x1 & 0xff;
+ // LL ~ 2^48*log2(1.0+index2/2^15)
+ LL = __LL_tbl[index2];
+
+ LH = LH + LL;
+
+ LH >>= (48-12 - 32);
+ result += LH;
+
+ return result;
+}
+
+
+/*
+ * straw2
+ *
+ * for reference, see:
+ *
+ * http://en.wikipedia.org/wiki/Exponential_distribution#Distribution_of_the_minimum_of_exponential_random_variables
+ *
+ */
+
+static int bucket_straw2_choose(struct crush_bucket_straw2 *bucket,
+ int x, int r)
+{
+ unsigned i, high = 0;
+ unsigned u;
+ unsigned w;
+ __s64 ln, draw, high_draw = 0;
+
+ for (i = 0; i < bucket->h.size; i++) {
+ w = bucket->item_weights[i];
+ if (w) {
+ u = crush_hash32_3(bucket->h.hash, x,
+ bucket->h.items[i], r);
+ u &= 0xffff;
+
+ /*
+ * for some reason slightly less than 0x10000 produces
+ * a slightly more accurate distribution... probably a
+ * rounding effect.
+ *
+ * the natural log lookup table maps [0,0xffff]
+ * (corresponding to real numbers [1/0x10000, 1] to
+ * [0, 0xffffffffffff] (corresponding to real numbers
+ * [-11.090355,0]).
+ */
+ ln = crush_ln(u) - 0x1000000000000ll;
+
+ /*
+ * divide by 16.16 fixed-point weight. note
+ * that the ln value is negative, so a larger
+ * weight means a larger (less negative) value
+ * for draw.
+ */
+ draw = div64_s64(ln, w);
+ } else {
+ draw = S64_MIN;
+ }
+
+ if (i == 0 || draw > high_draw) {
+ high = i;
+ high_draw = draw;
+ }
+ }
+ return bucket->h.items[high];
+}
+
+
+static int crush_bucket_choose(struct crush_bucket *in, int x, int r)
+{
+ dprintk(" crush_bucket_choose %d x=%d r=%d\n", in->id, x, r);
+ BUG_ON(in->size == 0);
+ switch (in->alg) {
+ case CRUSH_BUCKET_UNIFORM:
+ return bucket_uniform_choose((struct crush_bucket_uniform *)in,
+ x, r);
+ case CRUSH_BUCKET_LIST:
+ return bucket_list_choose((struct crush_bucket_list *)in,
+ x, r);
+ case CRUSH_BUCKET_TREE:
+ return bucket_tree_choose((struct crush_bucket_tree *)in,
+ x, r);
+ case CRUSH_BUCKET_STRAW:
+ return bucket_straw_choose((struct crush_bucket_straw *)in,
+ x, r);
+ case CRUSH_BUCKET_STRAW2:
+ return bucket_straw2_choose((struct crush_bucket_straw2 *)in,
+ x, r);
+ default:
+ dprintk("unknown bucket %d alg %d\n", in->id, in->alg);
+ return in->items[0];
+ }
+}
+
+
+/*
+ * true if device is marked "out" (failed, fully offloaded)
+ * of the cluster
+ */
+static int is_out(const struct crush_map *map,
+ const __u32 *weight, int weight_max,
+ int item, int x)
+{
+ if (item >= weight_max)
+ return 1;
+ if (weight[item] >= 0x10000)
+ return 0;
+ if (weight[item] == 0)
+ return 1;
+ if ((crush_hash32_2(CRUSH_HASH_RJENKINS1, x, item) & 0xffff)
+ < weight[item])
+ return 0;
+ return 1;
+}
+
+/**
+ * crush_choose_firstn - choose numrep distinct items of given type
+ * @map: the crush_map
+ * @bucket: the bucket we are choose an item from
+ * @x: crush input value
+ * @numrep: the number of items to choose
+ * @type: the type of item to choose
+ * @out: pointer to output vector
+ * @outpos: our position in that vector
+ * @out_size: size of the out vector
+ * @tries: number of attempts to make
+ * @recurse_tries: number of attempts to have recursive chooseleaf make
+ * @local_retries: localized retries
+ * @local_fallback_retries: localized fallback retries
+ * @recurse_to_leaf: true if we want one device under each item of given type (chooseleaf instead of choose)
+ * @vary_r: pass r to recursive calls
+ * @out2: second output vector for leaf items (if @recurse_to_leaf)
+ * @parent_r: r value passed from the parent
+ */
+static int crush_choose_firstn(const struct crush_map *map,
+ struct crush_bucket *bucket,
+ const __u32 *weight, int weight_max,
+ int x, int numrep, int type,
+ int *out, int outpos,
+ int out_size,
+ unsigned int tries,
+ unsigned int recurse_tries,
+ unsigned int local_retries,
+ unsigned int local_fallback_retries,
+ int recurse_to_leaf,
+ unsigned int vary_r,
+ int *out2,
+ int parent_r)
+{
+ int rep;
+ unsigned int ftotal, flocal;
+ int retry_descent, retry_bucket, skip_rep;
+ struct crush_bucket *in = bucket;
+ int r;
+ int i;
+ int item = 0;
+ int itemtype;
+ int collide, reject;
+ int count = out_size;
+
+ dprintk("CHOOSE%s bucket %d x %d outpos %d numrep %d tries %d recurse_tries %d local_retries %d local_fallback_retries %d parent_r %d\n",
+ recurse_to_leaf ? "_LEAF" : "",
+ bucket->id, x, outpos, numrep,
+ tries, recurse_tries, local_retries, local_fallback_retries,
+ parent_r);
+
+ for (rep = outpos; rep < numrep && count > 0 ; rep++) {
+ /* keep trying until we get a non-out, non-colliding item */
+ ftotal = 0;
+ skip_rep = 0;
+ do {
+ retry_descent = 0;
+ in = bucket; /* initial bucket */
+
+ /* choose through intervening buckets */
+ flocal = 0;
+ do {
+ collide = 0;
+ retry_bucket = 0;
+ r = rep + parent_r;
+ /* r' = r + f_total */
+ r += ftotal;
+
+ /* bucket choose */
+ if (in->size == 0) {
+ reject = 1;
+ goto reject;
+ }
+ if (local_fallback_retries > 0 &&
+ flocal >= (in->size>>1) &&
+ flocal > local_fallback_retries)
+ item = bucket_perm_choose(in, x, r);
+ else
+ item = crush_bucket_choose(in, x, r);
+ if (item >= map->max_devices) {
+ dprintk(" bad item %d\n", item);
+ skip_rep = 1;
+ break;
+ }
+
+ /* desired type? */
+ if (item < 0)
+ itemtype = map->buckets[-1-item]->type;
+ else
+ itemtype = 0;
+ dprintk(" item %d type %d\n", item, itemtype);
+
+ /* keep going? */
+ if (itemtype != type) {
+ if (item >= 0 ||
+ (-1-item) >= map->max_buckets) {
+ dprintk(" bad item type %d\n", type);
+ skip_rep = 1;
+ break;
+ }
+ in = map->buckets[-1-item];
+ retry_bucket = 1;
+ continue;
+ }
+
+ /* collision? */
+ for (i = 0; i < outpos; i++) {
+ if (out[i] == item) {
+ collide = 1;
+ break;
+ }
+ }
+
+ reject = 0;
+ if (!collide && recurse_to_leaf) {
+ if (item < 0) {
+ int sub_r;
+ if (vary_r)
+ sub_r = r >> (vary_r-1);
+ else
+ sub_r = 0;
+ if (crush_choose_firstn(map,
+ map->buckets[-1-item],
+ weight, weight_max,
+ x, outpos+1, 0,
+ out2, outpos, count,
+ recurse_tries, 0,
+ local_retries,
+ local_fallback_retries,
+ 0,
+ vary_r,
+ NULL,
+ sub_r) <= outpos)
+ /* didn't get leaf */
+ reject = 1;
+ } else {
+ /* we already have a leaf! */
+ out2[outpos] = item;
+ }
+ }
+
+ if (!reject) {
+ /* out? */
+ if (itemtype == 0)
+ reject = is_out(map, weight,
+ weight_max,
+ item, x);
+ else
+ reject = 0;
+ }
+
+reject:
+ if (reject || collide) {
+ ftotal++;
+ flocal++;
+
+ if (collide && flocal <= local_retries)
+ /* retry locally a few times */
+ retry_bucket = 1;
+ else if (local_fallback_retries > 0 &&
+ flocal <= in->size + local_fallback_retries)
+ /* exhaustive bucket search */
+ retry_bucket = 1;
+ else if (ftotal < tries)
+ /* then retry descent */
+ retry_descent = 1;
+ else
+ /* else give up */
+ skip_rep = 1;
+ dprintk(" reject %d collide %d "
+ "ftotal %u flocal %u\n",
+ reject, collide, ftotal,
+ flocal);
+ }
+ } while (retry_bucket);
+ } while (retry_descent);
+
+ if (skip_rep) {
+ dprintk("skip rep\n");
+ continue;
+ }
+
+ dprintk("CHOOSE got %d\n", item);
+ out[outpos] = item;
+ outpos++;
+ count--;
+ }
+
+ dprintk("CHOOSE returns %d\n", outpos);
+ return outpos;
+}
+
+
+/**
+ * crush_choose_indep: alternative breadth-first positionally stable mapping
+ *
+ */
+static void crush_choose_indep(const struct crush_map *map,
+ struct crush_bucket *bucket,
+ const __u32 *weight, int weight_max,
+ int x, int left, int numrep, int type,
+ int *out, int outpos,
+ unsigned int tries,
+ unsigned int recurse_tries,
+ int recurse_to_leaf,
+ int *out2,
+ int parent_r)
+{
+ struct crush_bucket *in = bucket;
+ int endpos = outpos + left;
+ int rep;
+ unsigned int ftotal;
+ int r;
+ int i;
+ int item = 0;
+ int itemtype;
+ int collide;
+
+ dprintk("CHOOSE%s INDEP bucket %d x %d outpos %d numrep %d\n", recurse_to_leaf ? "_LEAF" : "",
+ bucket->id, x, outpos, numrep);
+
+ /* initially my result is undefined */
+ for (rep = outpos; rep < endpos; rep++) {
+ out[rep] = CRUSH_ITEM_UNDEF;
+ if (out2)
+ out2[rep] = CRUSH_ITEM_UNDEF;
+ }
+
+ for (ftotal = 0; left > 0 && ftotal < tries; ftotal++) {
+ for (rep = outpos; rep < endpos; rep++) {
+ if (out[rep] != CRUSH_ITEM_UNDEF)
+ continue;
+
+ in = bucket; /* initial bucket */
+
+ /* choose through intervening buckets */
+ for (;;) {
+ /* note: we base the choice on the position
+ * even in the nested call. that means that
+ * if the first layer chooses the same bucket
+ * in a different position, we will tend to
+ * choose a different item in that bucket.
+ * this will involve more devices in data
+ * movement and tend to distribute the load.
+ */
+ r = rep + parent_r;
+
+ /* be careful */
+ if (in->alg == CRUSH_BUCKET_UNIFORM &&
+ in->size % numrep == 0)
+ /* r'=r+(n+1)*f_total */
+ r += (numrep+1) * ftotal;
+ else
+ /* r' = r + n*f_total */
+ r += numrep * ftotal;
+
+ /* bucket choose */
+ if (in->size == 0) {
+ dprintk(" empty bucket\n");
+ break;
+ }
+
+ item = crush_bucket_choose(in, x, r);
+ if (item >= map->max_devices) {
+ dprintk(" bad item %d\n", item);
+ out[rep] = CRUSH_ITEM_NONE;
+ if (out2)
+ out2[rep] = CRUSH_ITEM_NONE;
+ left--;
+ break;
+ }
+
+ /* desired type? */
+ if (item < 0)
+ itemtype = map->buckets[-1-item]->type;
+ else
+ itemtype = 0;
+ dprintk(" item %d type %d\n", item, itemtype);
+
+ /* keep going? */
+ if (itemtype != type) {
+ if (item >= 0 ||
+ (-1-item) >= map->max_buckets) {
+ dprintk(" bad item type %d\n", type);
+ out[rep] = CRUSH_ITEM_NONE;
+ if (out2)
+ out2[rep] =
+ CRUSH_ITEM_NONE;
+ left--;
+ break;
+ }
+ in = map->buckets[-1-item];
+ continue;
+ }
+
+ /* collision? */
+ collide = 0;
+ for (i = outpos; i < endpos; i++) {
+ if (out[i] == item) {
+ collide = 1;
+ break;
+ }
+ }
+ if (collide)
+ break;
+
+ if (recurse_to_leaf) {
+ if (item < 0) {
+ crush_choose_indep(map,
+ map->buckets[-1-item],
+ weight, weight_max,
+ x, 1, numrep, 0,
+ out2, rep,
+ recurse_tries, 0,
+ 0, NULL, r);
+ if (out2[rep] == CRUSH_ITEM_NONE) {
+ /* placed nothing; no leaf */
+ break;
+ }
+ } else {
+ /* we already have a leaf! */
+ out2[rep] = item;
+ }
+ }
+
+ /* out? */
+ if (itemtype == 0 &&
+ is_out(map, weight, weight_max, item, x))
+ break;
+
+ /* yay! */
+ out[rep] = item;
+ left--;
+ break;
+ }
+ }
+ }
+ for (rep = outpos; rep < endpos; rep++) {
+ if (out[rep] == CRUSH_ITEM_UNDEF) {
+ out[rep] = CRUSH_ITEM_NONE;
+ }
+ if (out2 && out2[rep] == CRUSH_ITEM_UNDEF) {
+ out2[rep] = CRUSH_ITEM_NONE;
+ }
+ }
+}
+
+/**
+ * crush_do_rule - calculate a mapping with the given input and rule
+ * @map: the crush_map
+ * @ruleno: the rule id
+ * @x: hash input
+ * @result: pointer to result vector
+ * @result_max: maximum result size
+ * @weight: weight vector (for map leaves)
+ * @weight_max: size of weight vector
+ * @scratch: scratch vector for private use; must be >= 3 * result_max
+ */
+int crush_do_rule(const struct crush_map *map,
+ int ruleno, int x, int *result, int result_max,
+ const __u32 *weight, int weight_max,
+ int *scratch)
+{
+ int result_len;
+ int *a = scratch;
+ int *b = scratch + result_max;
+ int *c = scratch + result_max*2;
+ int recurse_to_leaf;
+ int *w;
+ int wsize = 0;
+ int *o;
+ int osize;
+ int *tmp;
+ struct crush_rule *rule;
+ __u32 step;
+ int i, j;
+ int numrep;
+ int out_size;
+ /*
+ * the original choose_total_tries value was off by one (it
+ * counted "retries" and not "tries"). add one.
+ */
+ int choose_tries = map->choose_total_tries + 1;
+ int choose_leaf_tries = 0;
+ /*
+ * the local tries values were counted as "retries", though,
+ * and need no adjustment
+ */
+ int choose_local_retries = map->choose_local_tries;
+ int choose_local_fallback_retries = map->choose_local_fallback_tries;
+
+ int vary_r = map->chooseleaf_vary_r;
+
+ if ((__u32)ruleno >= map->max_rules) {
+ dprintk(" bad ruleno %d\n", ruleno);
+ return 0;
+ }
+
+ rule = map->rules[ruleno];
+ result_len = 0;
+ w = a;
+ o = b;
+
+ for (step = 0; step < rule->len; step++) {
+ int firstn = 0;
+ struct crush_rule_step *curstep = &rule->steps[step];
+
+ switch (curstep->op) {
+ case CRUSH_RULE_TAKE:
+ w[0] = curstep->arg1;
+ wsize = 1;
+ break;
+
+ case CRUSH_RULE_SET_CHOOSE_TRIES:
+ if (curstep->arg1 > 0)
+ choose_tries = curstep->arg1;
+ break;
+
+ case CRUSH_RULE_SET_CHOOSELEAF_TRIES:
+ if (curstep->arg1 > 0)
+ choose_leaf_tries = curstep->arg1;
+ break;
+
+ case CRUSH_RULE_SET_CHOOSE_LOCAL_TRIES:
+ if (curstep->arg1 >= 0)
+ choose_local_retries = curstep->arg1;
+ break;
+
+ case CRUSH_RULE_SET_CHOOSE_LOCAL_FALLBACK_TRIES:
+ if (curstep->arg1 >= 0)
+ choose_local_fallback_retries = curstep->arg1;
+ break;
+
+ case CRUSH_RULE_SET_CHOOSELEAF_VARY_R:
+ if (curstep->arg1 >= 0)
+ vary_r = curstep->arg1;
+ break;
+
+ case CRUSH_RULE_CHOOSELEAF_FIRSTN:
+ case CRUSH_RULE_CHOOSE_FIRSTN:
+ firstn = 1;
+ /* fall through */
+ case CRUSH_RULE_CHOOSELEAF_INDEP:
+ case CRUSH_RULE_CHOOSE_INDEP:
+ if (wsize == 0)
+ break;
+
+ recurse_to_leaf =
+ curstep->op ==
+ CRUSH_RULE_CHOOSELEAF_FIRSTN ||
+ curstep->op ==
+ CRUSH_RULE_CHOOSELEAF_INDEP;
+
+ /* reset output */
+ osize = 0;
+
+ for (i = 0; i < wsize; i++) {
+ /*
+ * see CRUSH_N, CRUSH_N_MINUS macros.
+ * basically, numrep <= 0 means relative to
+ * the provided result_max
+ */
+ numrep = curstep->arg1;
+ if (numrep <= 0) {
+ numrep += result_max;
+ if (numrep <= 0)
+ continue;
+ }
+ j = 0;
+ if (firstn) {
+ int recurse_tries;
+ if (choose_leaf_tries)
+ recurse_tries =
+ choose_leaf_tries;
+ else if (map->chooseleaf_descend_once)
+ recurse_tries = 1;
+ else
+ recurse_tries = choose_tries;
+ osize += crush_choose_firstn(
+ map,
+ map->buckets[-1-w[i]],
+ weight, weight_max,
+ x, numrep,
+ curstep->arg2,
+ o+osize, j,
+ result_max-osize,
+ choose_tries,
+ recurse_tries,
+ choose_local_retries,
+ choose_local_fallback_retries,
+ recurse_to_leaf,
+ vary_r,
+ c+osize,
+ 0);
+ } else {
+ out_size = ((numrep < (result_max-osize)) ?
+ numrep : (result_max-osize));
+ crush_choose_indep(
+ map,
+ map->buckets[-1-w[i]],
+ weight, weight_max,
+ x, out_size, numrep,
+ curstep->arg2,
+ o+osize, j,
+ choose_tries,
+ choose_leaf_tries ?
+ choose_leaf_tries : 1,
+ recurse_to_leaf,
+ c+osize,
+ 0);
+ osize += out_size;
+ }
+ }
+
+ if (recurse_to_leaf)
+ /* copy final _leaf_ values to output set */
+ memcpy(o, c, osize*sizeof(*o));
+
+ /* swap o and w arrays */
+ tmp = o;
+ o = w;
+ w = tmp;
+ wsize = osize;
+ break;
+
+
+ case CRUSH_RULE_EMIT:
+ for (i = 0; i < wsize && result_len < result_max; i++) {
+ result[result_len] = w[i];
+ result_len++;
+ }
+ wsize = 0;
+ break;
+
+ default:
+ dprintk(" unknown op %d at step %d\n",
+ curstep->op, step);
+ break;
+ }
+ }
+ return result_len;
+}
+
+