1 2 #ifdef __KERNEL__ 3 # include <linux/string.h> 4 # include <linux/slab.h> 5 # include <linux/bug.h> 6 # include <linux/kernel.h> 7 # ifndef dprintk 8 # define dprintk(args...) 9 # endif 10 #else 11 # include <string.h> 12 # include <stdio.h> 13 # include <stdlib.h> 14 # include <assert.h> 15 # define BUG_ON(x) assert(!(x)) 16 # define dprintk(args...) /* printf(args) */ 17 # define kmalloc(x, f) malloc(x) 18 # define kfree(x) free(x) 19 #endif 20 21 #include <linux/crush/crush.h> 22 #include <linux/crush/hash.h> 23 #include "crush_ln_table.h" 24 25 /* 26 * Implement the core CRUSH mapping algorithm. 27 */ 28 29 /** 30 * crush_find_rule - find a crush_rule id for a given ruleset, type, and size. 31 * @map: the crush_map 32 * @ruleset: the storage ruleset id (user defined) 33 * @type: storage ruleset type (user defined) 34 * @size: output set size 35 */ 36 int crush_find_rule(const struct crush_map *map, int ruleset, int type, int size) 37 { 38 __u32 i; 39 40 for (i = 0; i < map->max_rules; i++) { 41 if (map->rules[i] && 42 map->rules[i]->mask.ruleset == ruleset && 43 map->rules[i]->mask.type == type && 44 map->rules[i]->mask.min_size <= size && 45 map->rules[i]->mask.max_size >= size) 46 return i; 47 } 48 return -1; 49 } 50 51 52 /* 53 * bucket choose methods 54 * 55 * For each bucket algorithm, we have a "choose" method that, given a 56 * crush input @x and replica position (usually, position in output set) @r, 57 * will produce an item in the bucket. 58 */ 59 60 /* 61 * Choose based on a random permutation of the bucket. 62 * 63 * We used to use some prime number arithmetic to do this, but it 64 * wasn't very random, and had some other bad behaviors. Instead, we 65 * calculate an actual random permutation of the bucket members. 66 * Since this is expensive, we optimize for the r=0 case, which 67 * captures the vast majority of calls. 68 */ 69 static int bucket_perm_choose(struct crush_bucket *bucket, 70 int x, int r) 71 { 72 unsigned int pr = r % bucket->size; 73 unsigned int i, s; 74 75 /* start a new permutation if @x has changed */ 76 if (bucket->perm_x != (__u32)x || bucket->perm_n == 0) { 77 dprintk("bucket %d new x=%d\n", bucket->id, x); 78 bucket->perm_x = x; 79 80 /* optimize common r=0 case */ 81 if (pr == 0) { 82 s = crush_hash32_3(bucket->hash, x, bucket->id, 0) % 83 bucket->size; 84 bucket->perm[0] = s; 85 bucket->perm_n = 0xffff; /* magic value, see below */ 86 goto out; 87 } 88 89 for (i = 0; i < bucket->size; i++) 90 bucket->perm[i] = i; 91 bucket->perm_n = 0; 92 } else if (bucket->perm_n == 0xffff) { 93 /* clean up after the r=0 case above */ 94 for (i = 1; i < bucket->size; i++) 95 bucket->perm[i] = i; 96 bucket->perm[bucket->perm[0]] = 0; 97 bucket->perm_n = 1; 98 } 99 100 /* calculate permutation up to pr */ 101 for (i = 0; i < bucket->perm_n; i++) 102 dprintk(" perm_choose have %d: %d\n", i, bucket->perm[i]); 103 while (bucket->perm_n <= pr) { 104 unsigned int p = bucket->perm_n; 105 /* no point in swapping the final entry */ 106 if (p < bucket->size - 1) { 107 i = crush_hash32_3(bucket->hash, x, bucket->id, p) % 108 (bucket->size - p); 109 if (i) { 110 unsigned int t = bucket->perm[p + i]; 111 bucket->perm[p + i] = bucket->perm[p]; 112 bucket->perm[p] = t; 113 } 114 dprintk(" perm_choose swap %d with %d\n", p, p+i); 115 } 116 bucket->perm_n++; 117 } 118 for (i = 0; i < bucket->size; i++) 119 dprintk(" perm_choose %d: %d\n", i, bucket->perm[i]); 120 121 s = bucket->perm[pr]; 122 out: 123 dprintk(" perm_choose %d sz=%d x=%d r=%d (%d) s=%d\n", bucket->id, 124 bucket->size, x, r, pr, s); 125 return bucket->items[s]; 126 } 127 128 /* uniform */ 129 static int bucket_uniform_choose(struct crush_bucket_uniform *bucket, 130 int x, int r) 131 { 132 return bucket_perm_choose(&bucket->h, x, r); 133 } 134 135 /* list */ 136 static int bucket_list_choose(struct crush_bucket_list *bucket, 137 int x, int r) 138 { 139 int i; 140 141 for (i = bucket->h.size-1; i >= 0; i--) { 142 __u64 w = crush_hash32_4(bucket->h.hash,x, bucket->h.items[i], 143 r, bucket->h.id); 144 w &= 0xffff; 145 dprintk("list_choose i=%d x=%d r=%d item %d weight %x " 146 "sw %x rand %llx", 147 i, x, r, bucket->h.items[i], bucket->item_weights[i], 148 bucket->sum_weights[i], w); 149 w *= bucket->sum_weights[i]; 150 w = w >> 16; 151 /*dprintk(" scaled %llx\n", w);*/ 152 if (w < bucket->item_weights[i]) 153 return bucket->h.items[i]; 154 } 155 156 dprintk("bad list sums for bucket %d\n", bucket->h.id); 157 return bucket->h.items[0]; 158 } 159 160 161 /* (binary) tree */ 162 static int height(int n) 163 { 164 int h = 0; 165 while ((n & 1) == 0) { 166 h++; 167 n = n >> 1; 168 } 169 return h; 170 } 171 172 static int left(int x) 173 { 174 int h = height(x); 175 return x - (1 << (h-1)); 176 } 177 178 static int right(int x) 179 { 180 int h = height(x); 181 return x + (1 << (h-1)); 182 } 183 184 static int terminal(int x) 185 { 186 return x & 1; 187 } 188 189 static int bucket_tree_choose(struct crush_bucket_tree *bucket, 190 int x, int r) 191 { 192 int n; 193 __u32 w; 194 __u64 t; 195 196 /* start at root */ 197 n = bucket->num_nodes >> 1; 198 199 while (!terminal(n)) { 200 int l; 201 /* pick point in [0, w) */ 202 w = bucket->node_weights[n]; 203 t = (__u64)crush_hash32_4(bucket->h.hash, x, n, r, 204 bucket->h.id) * (__u64)w; 205 t = t >> 32; 206 207 /* descend to the left or right? */ 208 l = left(n); 209 if (t < bucket->node_weights[l]) 210 n = l; 211 else 212 n = right(n); 213 } 214 215 return bucket->h.items[n >> 1]; 216 } 217 218 219 /* straw */ 220 221 static int bucket_straw_choose(struct crush_bucket_straw *bucket, 222 int x, int r) 223 { 224 __u32 i; 225 int high = 0; 226 __u64 high_draw = 0; 227 __u64 draw; 228 229 for (i = 0; i < bucket->h.size; i++) { 230 draw = crush_hash32_3(bucket->h.hash, x, bucket->h.items[i], r); 231 draw &= 0xffff; 232 draw *= bucket->straws[i]; 233 if (i == 0 || draw > high_draw) { 234 high = i; 235 high_draw = draw; 236 } 237 } 238 return bucket->h.items[high]; 239 } 240 241 // compute 2^44*log2(input+1) 242 uint64_t crush_ln(unsigned xin) 243 { 244 unsigned x=xin, x1; 245 int iexpon, index1, index2; 246 uint64_t RH, LH, LL, xl64, result; 247 248 x++; 249 250 // normalize input 251 iexpon = 15; 252 while(!(x&0x18000)) { x<<=1; iexpon--; } 253 254 index1 = (x>>8)<<1; 255 // RH ~ 2^56/index1 256 RH = __RH_LH_tbl[index1 - 256]; 257 // LH ~ 2^48 * log2(index1/256) 258 LH = __RH_LH_tbl[index1 + 1 - 256]; 259 260 // RH*x ~ 2^48 * (2^15 + xf), xf<2^8 261 xl64 = (int64_t)x * RH; 262 xl64 >>= 48; 263 x1 = xl64; 264 265 result = iexpon; 266 result <<= (12 + 32); 267 268 index2 = x1 & 0xff; 269 // LL ~ 2^48*log2(1.0+index2/2^15) 270 LL = __LL_tbl[index2]; 271 272 LH = LH + LL; 273 274 LH >>= (48-12 - 32); 275 result += LH; 276 277 return result; 278 } 279 280 281 /* 282 * straw2 283 * 284 * for reference, see: 285 * 286 * http://en.wikipedia.org/wiki/Exponential_distribution#Distribution_of_the_minimum_of_exponential_random_variables 287 * 288 */ 289 290 static int bucket_straw2_choose(struct crush_bucket_straw2 *bucket, 291 int x, int r) 292 { 293 unsigned i, high = 0; 294 unsigned u; 295 unsigned w; 296 __s64 ln, draw, high_draw = 0; 297 298 for (i = 0; i < bucket->h.size; i++) { 299 w = bucket->item_weights[i]; 300 if (w) { 301 u = crush_hash32_3(bucket->h.hash, x, 302 bucket->h.items[i], r); 303 u &= 0xffff; 304 305 /* 306 * for some reason slightly less than 0x10000 produces 307 * a slightly more accurate distribution... probably a 308 * rounding effect. 309 * 310 * the natural log lookup table maps [0,0xffff] 311 * (corresponding to real numbers [1/0x10000, 1] to 312 * [0, 0xffffffffffff] (corresponding to real numbers 313 * [-11.090355,0]). 314 */ 315 ln = crush_ln(u) - 0x1000000000000ll; 316 317 /* 318 * divide by 16.16 fixed-point weight. note 319 * that the ln value is negative, so a larger 320 * weight means a larger (less negative) value 321 * for draw. 322 */ 323 draw = div64_s64(ln, w); 324 } else { 325 draw = S64_MIN; 326 } 327 328 if (i == 0 || draw > high_draw) { 329 high = i; 330 high_draw = draw; 331 } 332 } 333 return bucket->h.items[high]; 334 } 335 336 337 static int crush_bucket_choose(struct crush_bucket *in, int x, int r) 338 { 339 dprintk(" crush_bucket_choose %d x=%d r=%d\n", in->id, x, r); 340 BUG_ON(in->size == 0); 341 switch (in->alg) { 342 case CRUSH_BUCKET_UNIFORM: 343 return bucket_uniform_choose((struct crush_bucket_uniform *)in, 344 x, r); 345 case CRUSH_BUCKET_LIST: 346 return bucket_list_choose((struct crush_bucket_list *)in, 347 x, r); 348 case CRUSH_BUCKET_TREE: 349 return bucket_tree_choose((struct crush_bucket_tree *)in, 350 x, r); 351 case CRUSH_BUCKET_STRAW: 352 return bucket_straw_choose((struct crush_bucket_straw *)in, 353 x, r); 354 case CRUSH_BUCKET_STRAW2: 355 return bucket_straw2_choose((struct crush_bucket_straw2 *)in, 356 x, r); 357 default: 358 dprintk("unknown bucket %d alg %d\n", in->id, in->alg); 359 return in->items[0]; 360 } 361 } 362 363 364 /* 365 * true if device is marked "out" (failed, fully offloaded) 366 * of the cluster 367 */ 368 static int is_out(const struct crush_map *map, 369 const __u32 *weight, int weight_max, 370 int item, int x) 371 { 372 if (item >= weight_max) 373 return 1; 374 if (weight[item] >= 0x10000) 375 return 0; 376 if (weight[item] == 0) 377 return 1; 378 if ((crush_hash32_2(CRUSH_HASH_RJENKINS1, x, item) & 0xffff) 379 < weight[item]) 380 return 0; 381 return 1; 382 } 383 384 /** 385 * crush_choose_firstn - choose numrep distinct items of given type 386 * @map: the crush_map 387 * @bucket: the bucket we are choose an item from 388 * @x: crush input value 389 * @numrep: the number of items to choose 390 * @type: the type of item to choose 391 * @out: pointer to output vector 392 * @outpos: our position in that vector 393 * @out_size: size of the out vector 394 * @tries: number of attempts to make 395 * @recurse_tries: number of attempts to have recursive chooseleaf make 396 * @local_retries: localized retries 397 * @local_fallback_retries: localized fallback retries 398 * @recurse_to_leaf: true if we want one device under each item of given type (chooseleaf instead of choose) 399 * @vary_r: pass r to recursive calls 400 * @out2: second output vector for leaf items (if @recurse_to_leaf) 401 * @parent_r: r value passed from the parent 402 */ 403 static int crush_choose_firstn(const struct crush_map *map, 404 struct crush_bucket *bucket, 405 const __u32 *weight, int weight_max, 406 int x, int numrep, int type, 407 int *out, int outpos, 408 int out_size, 409 unsigned int tries, 410 unsigned int recurse_tries, 411 unsigned int local_retries, 412 unsigned int local_fallback_retries, 413 int recurse_to_leaf, 414 unsigned int vary_r, 415 int *out2, 416 int parent_r) 417 { 418 int rep; 419 unsigned int ftotal, flocal; 420 int retry_descent, retry_bucket, skip_rep; 421 struct crush_bucket *in = bucket; 422 int r; 423 int i; 424 int item = 0; 425 int itemtype; 426 int collide, reject; 427 int count = out_size; 428 429 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", 430 recurse_to_leaf ? "_LEAF" : "", 431 bucket->id, x, outpos, numrep, 432 tries, recurse_tries, local_retries, local_fallback_retries, 433 parent_r); 434 435 for (rep = outpos; rep < numrep && count > 0 ; rep++) { 436 /* keep trying until we get a non-out, non-colliding item */ 437 ftotal = 0; 438 skip_rep = 0; 439 do { 440 retry_descent = 0; 441 in = bucket; /* initial bucket */ 442 443 /* choose through intervening buckets */ 444 flocal = 0; 445 do { 446 collide = 0; 447 retry_bucket = 0; 448 r = rep + parent_r; 449 /* r' = r + f_total */ 450 r += ftotal; 451 452 /* bucket choose */ 453 if (in->size == 0) { 454 reject = 1; 455 goto reject; 456 } 457 if (local_fallback_retries > 0 && 458 flocal >= (in->size>>1) && 459 flocal > local_fallback_retries) 460 item = bucket_perm_choose(in, x, r); 461 else 462 item = crush_bucket_choose(in, x, r); 463 if (item >= map->max_devices) { 464 dprintk(" bad item %d\n", item); 465 skip_rep = 1; 466 break; 467 } 468 469 /* desired type? */ 470 if (item < 0) 471 itemtype = map->buckets[-1-item]->type; 472 else 473 itemtype = 0; 474 dprintk(" item %d type %d\n", item, itemtype); 475 476 /* keep going? */ 477 if (itemtype != type) { 478 if (item >= 0 || 479 (-1-item) >= map->max_buckets) { 480 dprintk(" bad item type %d\n", type); 481 skip_rep = 1; 482 break; 483 } 484 in = map->buckets[-1-item]; 485 retry_bucket = 1; 486 continue; 487 } 488 489 /* collision? */ 490 for (i = 0; i < outpos; i++) { 491 if (out[i] == item) { 492 collide = 1; 493 break; 494 } 495 } 496 497 reject = 0; 498 if (!collide && recurse_to_leaf) { 499 if (item < 0) { 500 int sub_r; 501 if (vary_r) 502 sub_r = r >> (vary_r-1); 503 else 504 sub_r = 0; 505 if (crush_choose_firstn(map, 506 map->buckets[-1-item], 507 weight, weight_max, 508 x, outpos+1, 0, 509 out2, outpos, count, 510 recurse_tries, 0, 511 local_retries, 512 local_fallback_retries, 513 0, 514 vary_r, 515 NULL, 516 sub_r) <= outpos) 517 /* didn't get leaf */ 518 reject = 1; 519 } else { 520 /* we already have a leaf! */ 521 out2[outpos] = item; 522 } 523 } 524 525 if (!reject) { 526 /* out? */ 527 if (itemtype == 0) 528 reject = is_out(map, weight, 529 weight_max, 530 item, x); 531 else 532 reject = 0; 533 } 534 535 reject: 536 if (reject || collide) { 537 ftotal++; 538 flocal++; 539 540 if (collide && flocal <= local_retries) 541 /* retry locally a few times */ 542 retry_bucket = 1; 543 else if (local_fallback_retries > 0 && 544 flocal <= in->size + local_fallback_retries) 545 /* exhaustive bucket search */ 546 retry_bucket = 1; 547 else if (ftotal < tries) 548 /* then retry descent */ 549 retry_descent = 1; 550 else 551 /* else give up */ 552 skip_rep = 1; 553 dprintk(" reject %d collide %d " 554 "ftotal %u flocal %u\n", 555 reject, collide, ftotal, 556 flocal); 557 } 558 } while (retry_bucket); 559 } while (retry_descent); 560 561 if (skip_rep) { 562 dprintk("skip rep\n"); 563 continue; 564 } 565 566 dprintk("CHOOSE got %d\n", item); 567 out[outpos] = item; 568 outpos++; 569 count--; 570 } 571 572 dprintk("CHOOSE returns %d\n", outpos); 573 return outpos; 574 } 575 576 577 /** 578 * crush_choose_indep: alternative breadth-first positionally stable mapping 579 * 580 */ 581 static void crush_choose_indep(const struct crush_map *map, 582 struct crush_bucket *bucket, 583 const __u32 *weight, int weight_max, 584 int x, int left, int numrep, int type, 585 int *out, int outpos, 586 unsigned int tries, 587 unsigned int recurse_tries, 588 int recurse_to_leaf, 589 int *out2, 590 int parent_r) 591 { 592 struct crush_bucket *in = bucket; 593 int endpos = outpos + left; 594 int rep; 595 unsigned int ftotal; 596 int r; 597 int i; 598 int item = 0; 599 int itemtype; 600 int collide; 601 602 dprintk("CHOOSE%s INDEP bucket %d x %d outpos %d numrep %d\n", recurse_to_leaf ? "_LEAF" : "", 603 bucket->id, x, outpos, numrep); 604 605 /* initially my result is undefined */ 606 for (rep = outpos; rep < endpos; rep++) { 607 out[rep] = CRUSH_ITEM_UNDEF; 608 if (out2) 609 out2[rep] = CRUSH_ITEM_UNDEF; 610 } 611 612 for (ftotal = 0; left > 0 && ftotal < tries; ftotal++) { 613 for (rep = outpos; rep < endpos; rep++) { 614 if (out[rep] != CRUSH_ITEM_UNDEF) 615 continue; 616 617 in = bucket; /* initial bucket */ 618 619 /* choose through intervening buckets */ 620 for (;;) { 621 /* note: we base the choice on the position 622 * even in the nested call. that means that 623 * if the first layer chooses the same bucket 624 * in a different position, we will tend to 625 * choose a different item in that bucket. 626 * this will involve more devices in data 627 * movement and tend to distribute the load. 628 */ 629 r = rep + parent_r; 630 631 /* be careful */ 632 if (in->alg == CRUSH_BUCKET_UNIFORM && 633 in->size % numrep == 0) 634 /* r'=r+(n+1)*f_total */ 635 r += (numrep+1) * ftotal; 636 else 637 /* r' = r + n*f_total */ 638 r += numrep * ftotal; 639 640 /* bucket choose */ 641 if (in->size == 0) { 642 dprintk(" empty bucket\n"); 643 break; 644 } 645 646 item = crush_bucket_choose(in, x, r); 647 if (item >= map->max_devices) { 648 dprintk(" bad item %d\n", item); 649 out[rep] = CRUSH_ITEM_NONE; 650 if (out2) 651 out2[rep] = CRUSH_ITEM_NONE; 652 left--; 653 break; 654 } 655 656 /* desired type? */ 657 if (item < 0) 658 itemtype = map->buckets[-1-item]->type; 659 else 660 itemtype = 0; 661 dprintk(" item %d type %d\n", item, itemtype); 662 663 /* keep going? */ 664 if (itemtype != type) { 665 if (item >= 0 || 666 (-1-item) >= map->max_buckets) { 667 dprintk(" bad item type %d\n", type); 668 out[rep] = CRUSH_ITEM_NONE; 669 if (out2) 670 out2[rep] = 671 CRUSH_ITEM_NONE; 672 left--; 673 break; 674 } 675 in = map->buckets[-1-item]; 676 continue; 677 } 678 679 /* collision? */ 680 collide = 0; 681 for (i = outpos; i < endpos; i++) { 682 if (out[i] == item) { 683 collide = 1; 684 break; 685 } 686 } 687 if (collide) 688 break; 689 690 if (recurse_to_leaf) { 691 if (item < 0) { 692 crush_choose_indep(map, 693 map->buckets[-1-item], 694 weight, weight_max, 695 x, 1, numrep, 0, 696 out2, rep, 697 recurse_tries, 0, 698 0, NULL, r); 699 if (out2[rep] == CRUSH_ITEM_NONE) { 700 /* placed nothing; no leaf */ 701 break; 702 } 703 } else { 704 /* we already have a leaf! */ 705 out2[rep] = item; 706 } 707 } 708 709 /* out? */ 710 if (itemtype == 0 && 711 is_out(map, weight, weight_max, item, x)) 712 break; 713 714 /* yay! */ 715 out[rep] = item; 716 left--; 717 break; 718 } 719 } 720 } 721 for (rep = outpos; rep < endpos; rep++) { 722 if (out[rep] == CRUSH_ITEM_UNDEF) { 723 out[rep] = CRUSH_ITEM_NONE; 724 } 725 if (out2 && out2[rep] == CRUSH_ITEM_UNDEF) { 726 out2[rep] = CRUSH_ITEM_NONE; 727 } 728 } 729 } 730 731 /** 732 * crush_do_rule - calculate a mapping with the given input and rule 733 * @map: the crush_map 734 * @ruleno: the rule id 735 * @x: hash input 736 * @result: pointer to result vector 737 * @result_max: maximum result size 738 * @weight: weight vector (for map leaves) 739 * @weight_max: size of weight vector 740 * @scratch: scratch vector for private use; must be >= 3 * result_max 741 */ 742 int crush_do_rule(const struct crush_map *map, 743 int ruleno, int x, int *result, int result_max, 744 const __u32 *weight, int weight_max, 745 int *scratch) 746 { 747 int result_len; 748 int *a = scratch; 749 int *b = scratch + result_max; 750 int *c = scratch + result_max*2; 751 int recurse_to_leaf; 752 int *w; 753 int wsize = 0; 754 int *o; 755 int osize; 756 int *tmp; 757 struct crush_rule *rule; 758 __u32 step; 759 int i, j; 760 int numrep; 761 int out_size; 762 /* 763 * the original choose_total_tries value was off by one (it 764 * counted "retries" and not "tries"). add one. 765 */ 766 int choose_tries = map->choose_total_tries + 1; 767 int choose_leaf_tries = 0; 768 /* 769 * the local tries values were counted as "retries", though, 770 * and need no adjustment 771 */ 772 int choose_local_retries = map->choose_local_tries; 773 int choose_local_fallback_retries = map->choose_local_fallback_tries; 774 775 int vary_r = map->chooseleaf_vary_r; 776 777 if ((__u32)ruleno >= map->max_rules) { 778 dprintk(" bad ruleno %d\n", ruleno); 779 return 0; 780 } 781 782 rule = map->rules[ruleno]; 783 result_len = 0; 784 w = a; 785 o = b; 786 787 for (step = 0; step < rule->len; step++) { 788 int firstn = 0; 789 struct crush_rule_step *curstep = &rule->steps[step]; 790 791 switch (curstep->op) { 792 case CRUSH_RULE_TAKE: 793 if ((curstep->arg1 >= 0 && 794 curstep->arg1 < map->max_devices) || 795 (-1-curstep->arg1 < map->max_buckets && 796 map->buckets[-1-curstep->arg1])) { 797 w[0] = curstep->arg1; 798 wsize = 1; 799 } else { 800 dprintk(" bad take value %d\n", curstep->arg1); 801 } 802 break; 803 804 case CRUSH_RULE_SET_CHOOSE_TRIES: 805 if (curstep->arg1 > 0) 806 choose_tries = curstep->arg1; 807 break; 808 809 case CRUSH_RULE_SET_CHOOSELEAF_TRIES: 810 if (curstep->arg1 > 0) 811 choose_leaf_tries = curstep->arg1; 812 break; 813 814 case CRUSH_RULE_SET_CHOOSE_LOCAL_TRIES: 815 if (curstep->arg1 >= 0) 816 choose_local_retries = curstep->arg1; 817 break; 818 819 case CRUSH_RULE_SET_CHOOSE_LOCAL_FALLBACK_TRIES: 820 if (curstep->arg1 >= 0) 821 choose_local_fallback_retries = curstep->arg1; 822 break; 823 824 case CRUSH_RULE_SET_CHOOSELEAF_VARY_R: 825 if (curstep->arg1 >= 0) 826 vary_r = curstep->arg1; 827 break; 828 829 case CRUSH_RULE_CHOOSELEAF_FIRSTN: 830 case CRUSH_RULE_CHOOSE_FIRSTN: 831 firstn = 1; 832 /* fall through */ 833 case CRUSH_RULE_CHOOSELEAF_INDEP: 834 case CRUSH_RULE_CHOOSE_INDEP: 835 if (wsize == 0) 836 break; 837 838 recurse_to_leaf = 839 curstep->op == 840 CRUSH_RULE_CHOOSELEAF_FIRSTN || 841 curstep->op == 842 CRUSH_RULE_CHOOSELEAF_INDEP; 843 844 /* reset output */ 845 osize = 0; 846 847 for (i = 0; i < wsize; i++) { 848 /* 849 * see CRUSH_N, CRUSH_N_MINUS macros. 850 * basically, numrep <= 0 means relative to 851 * the provided result_max 852 */ 853 numrep = curstep->arg1; 854 if (numrep <= 0) { 855 numrep += result_max; 856 if (numrep <= 0) 857 continue; 858 } 859 j = 0; 860 if (firstn) { 861 int recurse_tries; 862 if (choose_leaf_tries) 863 recurse_tries = 864 choose_leaf_tries; 865 else if (map->chooseleaf_descend_once) 866 recurse_tries = 1; 867 else 868 recurse_tries = choose_tries; 869 osize += crush_choose_firstn( 870 map, 871 map->buckets[-1-w[i]], 872 weight, weight_max, 873 x, numrep, 874 curstep->arg2, 875 o+osize, j, 876 result_max-osize, 877 choose_tries, 878 recurse_tries, 879 choose_local_retries, 880 choose_local_fallback_retries, 881 recurse_to_leaf, 882 vary_r, 883 c+osize, 884 0); 885 } else { 886 out_size = ((numrep < (result_max-osize)) ? 887 numrep : (result_max-osize)); 888 crush_choose_indep( 889 map, 890 map->buckets[-1-w[i]], 891 weight, weight_max, 892 x, out_size, numrep, 893 curstep->arg2, 894 o+osize, j, 895 choose_tries, 896 choose_leaf_tries ? 897 choose_leaf_tries : 1, 898 recurse_to_leaf, 899 c+osize, 900 0); 901 osize += out_size; 902 } 903 } 904 905 if (recurse_to_leaf) 906 /* copy final _leaf_ values to output set */ 907 memcpy(o, c, osize*sizeof(*o)); 908 909 /* swap o and w arrays */ 910 tmp = o; 911 o = w; 912 w = tmp; 913 wsize = osize; 914 break; 915 916 917 case CRUSH_RULE_EMIT: 918 for (i = 0; i < wsize && result_len < result_max; i++) { 919 result[result_len] = w[i]; 920 result_len++; 921 } 922 wsize = 0; 923 break; 924 925 default: 926 dprintk(" unknown op %d at step %d\n", 927 curstep->op, step); 928 break; 929 } 930 } 931 return result_len; 932 } 933 934 935