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...)
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 <linux/crush/mapper.h>
24
25
26
27
28
29
30
31
32
33
34
35
36int 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
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69static 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
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
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;
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
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
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
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];
122out:
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
129static 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
136static 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
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
162static 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
172static int left(int x)
173{
174 int h = height(x);
175 return x - (1 << (h-1));
176}
177
178static int right(int x)
179{
180 int h = height(x);
181 return x + (1 << (h-1));
182}
183
184static int terminal(int x)
185{
186 return x & 1;
187}
188
189static int bucket_tree_choose(struct crush_bucket_tree *bucket,
190 int x, int r)
191{
192 int n, l;
193 __u32 w;
194 __u64 t;
195
196
197 n = bucket->num_nodes >> 1;
198
199 while (!terminal(n)) {
200
201 w = bucket->node_weights[n];
202 t = (__u64)crush_hash32_4(bucket->h.hash, x, n, r,
203 bucket->h.id) * (__u64)w;
204 t = t >> 32;
205
206
207 l = left(n);
208 if (t < bucket->node_weights[l])
209 n = l;
210 else
211 n = right(n);
212 }
213
214 return bucket->h.items[n >> 1];
215}
216
217
218
219
220static int bucket_straw_choose(struct crush_bucket_straw *bucket,
221 int x, int r)
222{
223 __u32 i;
224 int high = 0;
225 __u64 high_draw = 0;
226 __u64 draw;
227
228 for (i = 0; i < bucket->h.size; i++) {
229 draw = crush_hash32_3(bucket->h.hash, x, bucket->h.items[i], r);
230 draw &= 0xffff;
231 draw *= bucket->straws[i];
232 if (i == 0 || draw > high_draw) {
233 high = i;
234 high_draw = draw;
235 }
236 }
237 return bucket->h.items[high];
238}
239
240static int crush_bucket_choose(struct crush_bucket *in, int x, int r)
241{
242 dprintk(" crush_bucket_choose %d x=%d r=%d\n", in->id, x, r);
243 BUG_ON(in->size == 0);
244 switch (in->alg) {
245 case CRUSH_BUCKET_UNIFORM:
246 return bucket_uniform_choose((struct crush_bucket_uniform *)in,
247 x, r);
248 case CRUSH_BUCKET_LIST:
249 return bucket_list_choose((struct crush_bucket_list *)in,
250 x, r);
251 case CRUSH_BUCKET_TREE:
252 return bucket_tree_choose((struct crush_bucket_tree *)in,
253 x, r);
254 case CRUSH_BUCKET_STRAW:
255 return bucket_straw_choose((struct crush_bucket_straw *)in,
256 x, r);
257 default:
258 dprintk("unknown bucket %d alg %d\n", in->id, in->alg);
259 return in->items[0];
260 }
261}
262
263
264
265
266
267static int is_out(const struct crush_map *map, const __u32 *weight, int item, int x)
268{
269 if (weight[item] >= 0x10000)
270 return 0;
271 if (weight[item] == 0)
272 return 1;
273 if ((crush_hash32_2(CRUSH_HASH_RJENKINS1, x, item) & 0xffff)
274 < weight[item])
275 return 0;
276 return 1;
277}
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292static int crush_choose(const struct crush_map *map,
293 struct crush_bucket *bucket,
294 const __u32 *weight,
295 int x, int numrep, int type,
296 int *out, int outpos,
297 int firstn, int recurse_to_leaf,
298 int *out2)
299{
300 int rep;
301 unsigned int ftotal, flocal;
302 int retry_descent, retry_bucket, skip_rep;
303 struct crush_bucket *in = bucket;
304 int r;
305 int i;
306 int item = 0;
307 int itemtype;
308 int collide, reject;
309
310 dprintk("CHOOSE%s bucket %d x %d outpos %d numrep %d\n", recurse_to_leaf ? "_LEAF" : "",
311 bucket->id, x, outpos, numrep);
312
313 for (rep = outpos; rep < numrep; rep++) {
314
315 ftotal = 0;
316 skip_rep = 0;
317 do {
318 retry_descent = 0;
319 in = bucket;
320
321
322 flocal = 0;
323 do {
324 collide = 0;
325 retry_bucket = 0;
326 r = rep;
327 if (in->alg == CRUSH_BUCKET_UNIFORM) {
328
329 if (firstn || (__u32)numrep >= in->size)
330
331 r += ftotal;
332 else if (in->size % numrep == 0)
333
334 r += (numrep+1) *
335 (flocal+ftotal);
336 else
337
338 r += numrep * (flocal+ftotal);
339 } else {
340 if (firstn)
341
342 r += ftotal;
343 else
344
345 r += numrep * (flocal+ftotal);
346 }
347
348
349 if (in->size == 0) {
350 reject = 1;
351 goto reject;
352 }
353 if (map->choose_local_fallback_tries > 0 &&
354 flocal >= (in->size>>1) &&
355 flocal > map->choose_local_fallback_tries)
356 item = bucket_perm_choose(in, x, r);
357 else
358 item = crush_bucket_choose(in, x, r);
359 if (item >= map->max_devices) {
360 dprintk(" bad item %d\n", item);
361 skip_rep = 1;
362 break;
363 }
364
365
366 if (item < 0)
367 itemtype = map->buckets[-1-item]->type;
368 else
369 itemtype = 0;
370 dprintk(" item %d type %d\n", item, itemtype);
371
372
373 if (itemtype != type) {
374 if (item >= 0 ||
375 (-1-item) >= map->max_buckets) {
376 dprintk(" bad item type %d\n", type);
377 skip_rep = 1;
378 break;
379 }
380 in = map->buckets[-1-item];
381 retry_bucket = 1;
382 continue;
383 }
384
385
386 for (i = 0; i < outpos; i++) {
387 if (out[i] == item) {
388 collide = 1;
389 break;
390 }
391 }
392
393 reject = 0;
394 if (recurse_to_leaf) {
395 if (item < 0) {
396 if (crush_choose(map,
397 map->buckets[-1-item],
398 weight,
399 x, outpos+1, 0,
400 out2, outpos,
401 firstn, 0,
402 NULL) <= outpos)
403
404 reject = 1;
405 } else {
406
407 out2[outpos] = item;
408 }
409 }
410
411 if (!reject) {
412
413 if (itemtype == 0)
414 reject = is_out(map, weight,
415 item, x);
416 else
417 reject = 0;
418 }
419
420reject:
421 if (reject || collide) {
422 ftotal++;
423 flocal++;
424
425 if (collide && flocal <= map->choose_local_tries)
426
427 retry_bucket = 1;
428 else if (map->choose_local_fallback_tries > 0 &&
429 flocal <= in->size + map->choose_local_fallback_tries)
430
431 retry_bucket = 1;
432 else if (ftotal <= map->choose_total_tries)
433
434 retry_descent = 1;
435 else
436
437 skip_rep = 1;
438 dprintk(" reject %d collide %d "
439 "ftotal %u flocal %u\n",
440 reject, collide, ftotal,
441 flocal);
442 }
443 } while (retry_bucket);
444 } while (retry_descent);
445
446 if (skip_rep) {
447 dprintk("skip rep\n");
448 continue;
449 }
450
451 dprintk("CHOOSE got %d\n", item);
452 out[outpos] = item;
453 outpos++;
454 }
455
456 dprintk("CHOOSE returns %d\n", outpos);
457 return outpos;
458}
459
460
461
462
463
464
465
466
467
468
469int crush_do_rule(const struct crush_map *map,
470 int ruleno, int x, int *result, int result_max,
471 const __u32 *weight)
472{
473 int result_len;
474 int a[CRUSH_MAX_SET];
475 int b[CRUSH_MAX_SET];
476 int c[CRUSH_MAX_SET];
477 int recurse_to_leaf;
478 int *w;
479 int wsize = 0;
480 int *o;
481 int osize;
482 int *tmp;
483 struct crush_rule *rule;
484 __u32 step;
485 int i, j;
486 int numrep;
487 int firstn;
488
489 if ((__u32)ruleno >= map->max_rules) {
490 dprintk(" bad ruleno %d\n", ruleno);
491 return 0;
492 }
493
494 rule = map->rules[ruleno];
495 result_len = 0;
496 w = a;
497 o = b;
498
499 for (step = 0; step < rule->len; step++) {
500 struct crush_rule_step *curstep = &rule->steps[step];
501
502 firstn = 0;
503 switch (curstep->op) {
504 case CRUSH_RULE_TAKE:
505 w[0] = curstep->arg1;
506 wsize = 1;
507 break;
508
509 case CRUSH_RULE_CHOOSE_LEAF_FIRSTN:
510 case CRUSH_RULE_CHOOSE_FIRSTN:
511 firstn = 1;
512
513 case CRUSH_RULE_CHOOSE_LEAF_INDEP:
514 case CRUSH_RULE_CHOOSE_INDEP:
515 if (wsize == 0)
516 break;
517
518 recurse_to_leaf =
519 curstep->op ==
520 CRUSH_RULE_CHOOSE_LEAF_FIRSTN ||
521 curstep->op ==
522 CRUSH_RULE_CHOOSE_LEAF_INDEP;
523
524
525 osize = 0;
526
527 for (i = 0; i < wsize; i++) {
528
529
530
531
532
533 numrep = curstep->arg1;
534 if (numrep <= 0) {
535 numrep += result_max;
536 if (numrep <= 0)
537 continue;
538 }
539 j = 0;
540 osize += crush_choose(map,
541 map->buckets[-1-w[i]],
542 weight,
543 x, numrep,
544 curstep->arg2,
545 o+osize, j,
546 firstn,
547 recurse_to_leaf, c+osize);
548 }
549
550 if (recurse_to_leaf)
551
552 memcpy(o, c, osize*sizeof(*o));
553
554
555 tmp = o;
556 o = w;
557 w = tmp;
558 wsize = osize;
559 break;
560
561
562 case CRUSH_RULE_EMIT:
563 for (i = 0; i < wsize && result_len < result_max; i++) {
564 result[result_len] = w[i];
565 result_len++;
566 }
567 wsize = 0;
568 break;
569
570 default:
571 dprintk(" unknown op %d at step %d\n",
572 curstep->op, step);
573 break;
574 }
575 }
576 return result_len;
577}
578
579
580