blob: cb4578a327b9d2841d43b58afd9be238d5d38a6c [file] [log] [blame]
Kent Overstreetcafe5632013-03-23 16:11:31 -07001/*
2 * Code for working with individual keys, and sorted sets of keys with in a
3 * btree node
4 *
5 * Copyright 2012 Google, Inc.
6 */
7
8#include "bcache.h"
9#include "btree.h"
10#include "debug.h"
11
12#include <linux/random.h>
Geert Uytterhoevencd953ed2013-03-27 18:56:28 +010013#include <linux/prefetch.h>
Kent Overstreetcafe5632013-03-23 16:11:31 -070014
15/* Keylists */
16
17void bch_keylist_copy(struct keylist *dest, struct keylist *src)
18{
19 *dest = *src;
20
21 if (src->list == src->d) {
22 size_t n = (uint64_t *) src->top - src->d;
23 dest->top = (struct bkey *) &dest->d[n];
24 dest->list = dest->d;
25 }
26}
27
28int bch_keylist_realloc(struct keylist *l, int nptrs, struct cache_set *c)
29{
30 unsigned oldsize = (uint64_t *) l->top - l->list;
31 unsigned newsize = oldsize + 2 + nptrs;
32 uint64_t *new;
33
34 /* The journalling code doesn't handle the case where the keys to insert
35 * is bigger than an empty write: If we just return -ENOMEM here,
36 * bio_insert() and bio_invalidate() will insert the keys created so far
37 * and finish the rest when the keylist is empty.
38 */
39 if (newsize * sizeof(uint64_t) > block_bytes(c) - sizeof(struct jset))
40 return -ENOMEM;
41
42 newsize = roundup_pow_of_two(newsize);
43
44 if (newsize <= KEYLIST_INLINE ||
45 roundup_pow_of_two(oldsize) == newsize)
46 return 0;
47
48 new = krealloc(l->list == l->d ? NULL : l->list,
49 sizeof(uint64_t) * newsize, GFP_NOIO);
50
51 if (!new)
52 return -ENOMEM;
53
54 if (l->list == l->d)
55 memcpy(new, l->list, sizeof(uint64_t) * KEYLIST_INLINE);
56
57 l->list = new;
58 l->top = (struct bkey *) (&l->list[oldsize]);
59
60 return 0;
61}
62
63struct bkey *bch_keylist_pop(struct keylist *l)
64{
65 struct bkey *k = l->bottom;
66
67 if (k == l->top)
68 return NULL;
69
70 while (bkey_next(k) != l->top)
71 k = bkey_next(k);
72
73 return l->top = k;
74}
75
76/* Pointer validation */
77
78bool __bch_ptr_invalid(struct cache_set *c, int level, const struct bkey *k)
79{
80 unsigned i;
81
82 if (level && (!KEY_PTRS(k) || !KEY_SIZE(k) || KEY_DIRTY(k)))
83 goto bad;
84
85 if (!level && KEY_SIZE(k) > KEY_OFFSET(k))
86 goto bad;
87
88 if (!KEY_SIZE(k))
89 return true;
90
91 for (i = 0; i < KEY_PTRS(k); i++)
92 if (ptr_available(c, k, i)) {
93 struct cache *ca = PTR_CACHE(c, k, i);
94 size_t bucket = PTR_BUCKET_NR(c, k, i);
95 size_t r = bucket_remainder(c, PTR_OFFSET(k, i));
96
97 if (KEY_SIZE(k) + r > c->sb.bucket_size ||
98 bucket < ca->sb.first_bucket ||
99 bucket >= ca->sb.nbuckets)
100 goto bad;
101 }
102
103 return false;
104bad:
105 cache_bug(c, "spotted bad key %s: %s", pkey(k), bch_ptr_status(c, k));
106 return true;
107}
108
109bool bch_ptr_bad(struct btree *b, const struct bkey *k)
110{
111 struct bucket *g;
112 unsigned i, stale;
113
114 if (!bkey_cmp(k, &ZERO_KEY) ||
115 !KEY_PTRS(k) ||
116 bch_ptr_invalid(b, k))
117 return true;
118
119 if (KEY_PTRS(k) && PTR_DEV(k, 0) == PTR_CHECK_DEV)
120 return true;
121
122 for (i = 0; i < KEY_PTRS(k); i++)
123 if (ptr_available(b->c, k, i)) {
124 g = PTR_BUCKET(b->c, k, i);
125 stale = ptr_stale(b->c, k, i);
126
127 btree_bug_on(stale > 96, b,
128 "key too stale: %i, need_gc %u",
129 stale, b->c->need_gc);
130
131 btree_bug_on(stale && KEY_DIRTY(k) && KEY_SIZE(k),
132 b, "stale dirty pointer");
133
134 if (stale)
135 return true;
136
137#ifdef CONFIG_BCACHE_EDEBUG
138 if (!mutex_trylock(&b->c->bucket_lock))
139 continue;
140
141 if (b->level) {
142 if (KEY_DIRTY(k) ||
143 g->prio != BTREE_PRIO ||
144 (b->c->gc_mark_valid &&
145 GC_MARK(g) != GC_MARK_METADATA))
146 goto bug;
147
148 } else {
149 if (g->prio == BTREE_PRIO)
150 goto bug;
151
152 if (KEY_DIRTY(k) &&
153 b->c->gc_mark_valid &&
154 GC_MARK(g) != GC_MARK_DIRTY)
155 goto bug;
156 }
157 mutex_unlock(&b->c->bucket_lock);
158#endif
159 }
160
161 return false;
162#ifdef CONFIG_BCACHE_EDEBUG
163bug:
164 mutex_unlock(&b->c->bucket_lock);
Kent Overstreetb1a67b02013-03-25 11:46:44 -0700165 btree_bug(b,
166"inconsistent pointer %s: bucket %zu pin %i prio %i gen %i last_gc %i mark %llu gc_gen %i",
167 pkey(k), PTR_BUCKET_NR(b->c, k, i), atomic_read(&g->pin),
Kent Overstreetcafe5632013-03-23 16:11:31 -0700168 g->prio, g->gen, g->last_gc, GC_MARK(g), g->gc_gen);
169 return true;
170#endif
171}
172
173/* Key/pointer manipulation */
174
175void bch_bkey_copy_single_ptr(struct bkey *dest, const struct bkey *src,
176 unsigned i)
177{
178 BUG_ON(i > KEY_PTRS(src));
179
180 /* Only copy the header, key, and one pointer. */
181 memcpy(dest, src, 2 * sizeof(uint64_t));
182 dest->ptr[0] = src->ptr[i];
183 SET_KEY_PTRS(dest, 1);
184 /* We didn't copy the checksum so clear that bit. */
185 SET_KEY_CSUM(dest, 0);
186}
187
188bool __bch_cut_front(const struct bkey *where, struct bkey *k)
189{
190 unsigned i, len = 0;
191
192 if (bkey_cmp(where, &START_KEY(k)) <= 0)
193 return false;
194
195 if (bkey_cmp(where, k) < 0)
196 len = KEY_OFFSET(k) - KEY_OFFSET(where);
197 else
198 bkey_copy_key(k, where);
199
200 for (i = 0; i < KEY_PTRS(k); i++)
201 SET_PTR_OFFSET(k, i, PTR_OFFSET(k, i) + KEY_SIZE(k) - len);
202
203 BUG_ON(len > KEY_SIZE(k));
204 SET_KEY_SIZE(k, len);
205 return true;
206}
207
208bool __bch_cut_back(const struct bkey *where, struct bkey *k)
209{
210 unsigned len = 0;
211
212 if (bkey_cmp(where, k) >= 0)
213 return false;
214
215 BUG_ON(KEY_INODE(where) != KEY_INODE(k));
216
217 if (bkey_cmp(where, &START_KEY(k)) > 0)
218 len = KEY_OFFSET(where) - KEY_START(k);
219
220 bkey_copy_key(k, where);
221
222 BUG_ON(len > KEY_SIZE(k));
223 SET_KEY_SIZE(k, len);
224 return true;
225}
226
227static uint64_t merge_chksums(struct bkey *l, struct bkey *r)
228{
229 return (l->ptr[KEY_PTRS(l)] + r->ptr[KEY_PTRS(r)]) &
230 ~((uint64_t)1 << 63);
231}
232
233/* Tries to merge l and r: l should be lower than r
234 * Returns true if we were able to merge. If we did merge, l will be the merged
235 * key, r will be untouched.
236 */
237bool bch_bkey_try_merge(struct btree *b, struct bkey *l, struct bkey *r)
238{
239 unsigned i;
240
241 if (key_merging_disabled(b->c))
242 return false;
243
244 if (KEY_PTRS(l) != KEY_PTRS(r) ||
245 KEY_DIRTY(l) != KEY_DIRTY(r) ||
246 bkey_cmp(l, &START_KEY(r)))
247 return false;
248
249 for (i = 0; i < KEY_PTRS(l); i++)
250 if (l->ptr[i] + PTR(0, KEY_SIZE(l), 0) != r->ptr[i] ||
251 PTR_BUCKET_NR(b->c, l, i) != PTR_BUCKET_NR(b->c, r, i))
252 return false;
253
254 /* Keys with no pointers aren't restricted to one bucket and could
255 * overflow KEY_SIZE
256 */
257 if (KEY_SIZE(l) + KEY_SIZE(r) > USHRT_MAX) {
258 SET_KEY_OFFSET(l, KEY_OFFSET(l) + USHRT_MAX - KEY_SIZE(l));
259 SET_KEY_SIZE(l, USHRT_MAX);
260
261 bch_cut_front(l, r);
262 return false;
263 }
264
265 if (KEY_CSUM(l)) {
266 if (KEY_CSUM(r))
267 l->ptr[KEY_PTRS(l)] = merge_chksums(l, r);
268 else
269 SET_KEY_CSUM(l, 0);
270 }
271
272 SET_KEY_OFFSET(l, KEY_OFFSET(l) + KEY_SIZE(r));
273 SET_KEY_SIZE(l, KEY_SIZE(l) + KEY_SIZE(r));
274
275 return true;
276}
277
278/* Binary tree stuff for auxiliary search trees */
279
280static unsigned inorder_next(unsigned j, unsigned size)
281{
282 if (j * 2 + 1 < size) {
283 j = j * 2 + 1;
284
285 while (j * 2 < size)
286 j *= 2;
287 } else
288 j >>= ffz(j) + 1;
289
290 return j;
291}
292
293static unsigned inorder_prev(unsigned j, unsigned size)
294{
295 if (j * 2 < size) {
296 j = j * 2;
297
298 while (j * 2 + 1 < size)
299 j = j * 2 + 1;
300 } else
301 j >>= ffs(j);
302
303 return j;
304}
305
306/* I have no idea why this code works... and I'm the one who wrote it
307 *
308 * However, I do know what it does:
309 * Given a binary tree constructed in an array (i.e. how you normally implement
310 * a heap), it converts a node in the tree - referenced by array index - to the
311 * index it would have if you did an inorder traversal.
312 *
313 * Also tested for every j, size up to size somewhere around 6 million.
314 *
315 * The binary tree starts at array index 1, not 0
316 * extra is a function of size:
317 * extra = (size - rounddown_pow_of_two(size - 1)) << 1;
318 */
319static unsigned __to_inorder(unsigned j, unsigned size, unsigned extra)
320{
321 unsigned b = fls(j);
322 unsigned shift = fls(size - 1) - b;
323
324 j ^= 1U << (b - 1);
325 j <<= 1;
326 j |= 1;
327 j <<= shift;
328
329 if (j > extra)
330 j -= (j - extra) >> 1;
331
332 return j;
333}
334
335static unsigned to_inorder(unsigned j, struct bset_tree *t)
336{
337 return __to_inorder(j, t->size, t->extra);
338}
339
340static unsigned __inorder_to_tree(unsigned j, unsigned size, unsigned extra)
341{
342 unsigned shift;
343
344 if (j > extra)
345 j += j - extra;
346
347 shift = ffs(j);
348
349 j >>= shift;
350 j |= roundup_pow_of_two(size) >> shift;
351
352 return j;
353}
354
355static unsigned inorder_to_tree(unsigned j, struct bset_tree *t)
356{
357 return __inorder_to_tree(j, t->size, t->extra);
358}
359
360#if 0
361void inorder_test(void)
362{
363 unsigned long done = 0;
364 ktime_t start = ktime_get();
365
366 for (unsigned size = 2;
367 size < 65536000;
368 size++) {
369 unsigned extra = (size - rounddown_pow_of_two(size - 1)) << 1;
370 unsigned i = 1, j = rounddown_pow_of_two(size - 1);
371
372 if (!(size % 4096))
373 printk(KERN_NOTICE "loop %u, %llu per us\n", size,
374 done / ktime_us_delta(ktime_get(), start));
375
376 while (1) {
377 if (__inorder_to_tree(i, size, extra) != j)
378 panic("size %10u j %10u i %10u", size, j, i);
379
380 if (__to_inorder(j, size, extra) != i)
381 panic("size %10u j %10u i %10u", size, j, i);
382
383 if (j == rounddown_pow_of_two(size) - 1)
384 break;
385
386 BUG_ON(inorder_prev(inorder_next(j, size), size) != j);
387
388 j = inorder_next(j, size);
389 i++;
390 }
391
392 done += size - 1;
393 }
394}
395#endif
396
397/*
398 * Cacheline/offset <-> bkey pointer arithmatic:
399 *
400 * t->tree is a binary search tree in an array; each node corresponds to a key
401 * in one cacheline in t->set (BSET_CACHELINE bytes).
402 *
403 * This means we don't have to store the full index of the key that a node in
404 * the binary tree points to; to_inorder() gives us the cacheline, and then
405 * bkey_float->m gives us the offset within that cacheline, in units of 8 bytes.
406 *
407 * cacheline_to_bkey() and friends abstract out all the pointer arithmatic to
408 * make this work.
409 *
410 * To construct the bfloat for an arbitrary key we need to know what the key
411 * immediately preceding it is: we have to check if the two keys differ in the
412 * bits we're going to store in bkey_float->mantissa. t->prev[j] stores the size
413 * of the previous key so we can walk backwards to it from t->tree[j]'s key.
414 */
415
416static struct bkey *cacheline_to_bkey(struct bset_tree *t, unsigned cacheline,
417 unsigned offset)
418{
419 return ((void *) t->data) + cacheline * BSET_CACHELINE + offset * 8;
420}
421
422static unsigned bkey_to_cacheline(struct bset_tree *t, struct bkey *k)
423{
424 return ((void *) k - (void *) t->data) / BSET_CACHELINE;
425}
426
427static unsigned bkey_to_cacheline_offset(struct bkey *k)
428{
429 return ((size_t) k & (BSET_CACHELINE - 1)) / sizeof(uint64_t);
430}
431
432static struct bkey *tree_to_bkey(struct bset_tree *t, unsigned j)
433{
434 return cacheline_to_bkey(t, to_inorder(j, t), t->tree[j].m);
435}
436
437static struct bkey *tree_to_prev_bkey(struct bset_tree *t, unsigned j)
438{
439 return (void *) (((uint64_t *) tree_to_bkey(t, j)) - t->prev[j]);
440}
441
442/*
443 * For the write set - the one we're currently inserting keys into - we don't
444 * maintain a full search tree, we just keep a simple lookup table in t->prev.
445 */
446static struct bkey *table_to_bkey(struct bset_tree *t, unsigned cacheline)
447{
448 return cacheline_to_bkey(t, cacheline, t->prev[cacheline]);
449}
450
451static inline uint64_t shrd128(uint64_t high, uint64_t low, uint8_t shift)
452{
453#ifdef CONFIG_X86_64
454 asm("shrd %[shift],%[high],%[low]"
455 : [low] "+Rm" (low)
456 : [high] "R" (high),
457 [shift] "ci" (shift)
458 : "cc");
459#else
460 low >>= shift;
461 low |= (high << 1) << (63U - shift);
462#endif
463 return low;
464}
465
466static inline unsigned bfloat_mantissa(const struct bkey *k,
467 struct bkey_float *f)
468{
469 const uint64_t *p = &k->low - (f->exponent >> 6);
470 return shrd128(p[-1], p[0], f->exponent & 63) & BKEY_MANTISSA_MASK;
471}
472
473static void make_bfloat(struct bset_tree *t, unsigned j)
474{
475 struct bkey_float *f = &t->tree[j];
476 struct bkey *m = tree_to_bkey(t, j);
477 struct bkey *p = tree_to_prev_bkey(t, j);
478
479 struct bkey *l = is_power_of_2(j)
480 ? t->data->start
481 : tree_to_prev_bkey(t, j >> ffs(j));
482
483 struct bkey *r = is_power_of_2(j + 1)
484 ? node(t->data, t->data->keys - bkey_u64s(&t->end))
485 : tree_to_bkey(t, j >> (ffz(j) + 1));
486
487 BUG_ON(m < l || m > r);
488 BUG_ON(bkey_next(p) != m);
489
490 if (KEY_INODE(l) != KEY_INODE(r))
491 f->exponent = fls64(KEY_INODE(r) ^ KEY_INODE(l)) + 64;
492 else
493 f->exponent = fls64(r->low ^ l->low);
494
495 f->exponent = max_t(int, f->exponent - BKEY_MANTISSA_BITS, 0);
496
497 /*
498 * Setting f->exponent = 127 flags this node as failed, and causes the
499 * lookup code to fall back to comparing against the original key.
500 */
501
502 if (bfloat_mantissa(m, f) != bfloat_mantissa(p, f))
503 f->mantissa = bfloat_mantissa(m, f) - 1;
504 else
505 f->exponent = 127;
506}
507
508static void bset_alloc_tree(struct btree *b, struct bset_tree *t)
509{
510 if (t != b->sets) {
511 unsigned j = roundup(t[-1].size,
512 64 / sizeof(struct bkey_float));
513
514 t->tree = t[-1].tree + j;
515 t->prev = t[-1].prev + j;
516 }
517
518 while (t < b->sets + MAX_BSETS)
519 t++->size = 0;
520}
521
522static void bset_build_unwritten_tree(struct btree *b)
523{
524 struct bset_tree *t = b->sets + b->nsets;
525
526 bset_alloc_tree(b, t);
527
528 if (t->tree != b->sets->tree + bset_tree_space(b)) {
529 t->prev[0] = bkey_to_cacheline_offset(t->data->start);
530 t->size = 1;
531 }
532}
533
534static void bset_build_written_tree(struct btree *b)
535{
536 struct bset_tree *t = b->sets + b->nsets;
537 struct bkey *k = t->data->start;
538 unsigned j, cacheline = 1;
539
540 bset_alloc_tree(b, t);
541
542 t->size = min_t(unsigned,
543 bkey_to_cacheline(t, end(t->data)),
544 b->sets->tree + bset_tree_space(b) - t->tree);
545
546 if (t->size < 2) {
547 t->size = 0;
548 return;
549 }
550
551 t->extra = (t->size - rounddown_pow_of_two(t->size - 1)) << 1;
552
553 /* First we figure out where the first key in each cacheline is */
554 for (j = inorder_next(0, t->size);
555 j;
556 j = inorder_next(j, t->size)) {
557 while (bkey_to_cacheline(t, k) != cacheline)
558 k = bkey_next(k);
559
560 t->prev[j] = bkey_u64s(k);
561 k = bkey_next(k);
562 cacheline++;
563 t->tree[j].m = bkey_to_cacheline_offset(k);
564 }
565
566 while (bkey_next(k) != end(t->data))
567 k = bkey_next(k);
568
569 t->end = *k;
570
571 /* Then we build the tree */
572 for (j = inorder_next(0, t->size);
573 j;
574 j = inorder_next(j, t->size))
575 make_bfloat(t, j);
576}
577
578void bch_bset_fix_invalidated_key(struct btree *b, struct bkey *k)
579{
580 struct bset_tree *t;
581 unsigned inorder, j = 1;
582
583 for (t = b->sets; t <= &b->sets[b->nsets]; t++)
584 if (k < end(t->data))
585 goto found_set;
586
587 BUG();
588found_set:
589 if (!t->size || !bset_written(b, t))
590 return;
591
592 inorder = bkey_to_cacheline(t, k);
593
594 if (k == t->data->start)
595 goto fix_left;
596
597 if (bkey_next(k) == end(t->data)) {
598 t->end = *k;
599 goto fix_right;
600 }
601
602 j = inorder_to_tree(inorder, t);
603
604 if (j &&
605 j < t->size &&
606 k == tree_to_bkey(t, j))
607fix_left: do {
608 make_bfloat(t, j);
609 j = j * 2;
610 } while (j < t->size);
611
612 j = inorder_to_tree(inorder + 1, t);
613
614 if (j &&
615 j < t->size &&
616 k == tree_to_prev_bkey(t, j))
617fix_right: do {
618 make_bfloat(t, j);
619 j = j * 2 + 1;
620 } while (j < t->size);
621}
622
623void bch_bset_fix_lookup_table(struct btree *b, struct bkey *k)
624{
625 struct bset_tree *t = &b->sets[b->nsets];
626 unsigned shift = bkey_u64s(k);
627 unsigned j = bkey_to_cacheline(t, k);
628
629 /* We're getting called from btree_split() or btree_gc, just bail out */
630 if (!t->size)
631 return;
632
633 /* k is the key we just inserted; we need to find the entry in the
634 * lookup table for the first key that is strictly greater than k:
635 * it's either k's cacheline or the next one
636 */
637 if (j < t->size &&
638 table_to_bkey(t, j) <= k)
639 j++;
640
641 /* Adjust all the lookup table entries, and find a new key for any that
642 * have gotten too big
643 */
644 for (; j < t->size; j++) {
645 t->prev[j] += shift;
646
647 if (t->prev[j] > 7) {
648 k = table_to_bkey(t, j - 1);
649
650 while (k < cacheline_to_bkey(t, j, 0))
651 k = bkey_next(k);
652
653 t->prev[j] = bkey_to_cacheline_offset(k);
654 }
655 }
656
657 if (t->size == b->sets->tree + bset_tree_space(b) - t->tree)
658 return;
659
660 /* Possibly add a new entry to the end of the lookup table */
661
662 for (k = table_to_bkey(t, t->size - 1);
663 k != end(t->data);
664 k = bkey_next(k))
665 if (t->size == bkey_to_cacheline(t, k)) {
666 t->prev[t->size] = bkey_to_cacheline_offset(k);
667 t->size++;
668 }
669}
670
671void bch_bset_init_next(struct btree *b)
672{
673 struct bset *i = write_block(b);
674
675 if (i != b->sets[0].data) {
676 b->sets[++b->nsets].data = i;
677 i->seq = b->sets[0].data->seq;
678 } else
679 get_random_bytes(&i->seq, sizeof(uint64_t));
680
681 i->magic = bset_magic(b->c);
682 i->version = 0;
683 i->keys = 0;
684
685 bset_build_unwritten_tree(b);
686}
687
688struct bset_search_iter {
689 struct bkey *l, *r;
690};
691
692static struct bset_search_iter bset_search_write_set(struct btree *b,
693 struct bset_tree *t,
694 const struct bkey *search)
695{
696 unsigned li = 0, ri = t->size;
697
698 BUG_ON(!b->nsets &&
699 t->size < bkey_to_cacheline(t, end(t->data)));
700
701 while (li + 1 != ri) {
702 unsigned m = (li + ri) >> 1;
703
704 if (bkey_cmp(table_to_bkey(t, m), search) > 0)
705 ri = m;
706 else
707 li = m;
708 }
709
710 return (struct bset_search_iter) {
711 table_to_bkey(t, li),
712 ri < t->size ? table_to_bkey(t, ri) : end(t->data)
713 };
714}
715
716static struct bset_search_iter bset_search_tree(struct btree *b,
717 struct bset_tree *t,
718 const struct bkey *search)
719{
720 struct bkey *l, *r;
721 struct bkey_float *f;
722 unsigned inorder, j, n = 1;
723
724 do {
725 unsigned p = n << 4;
726 p &= ((int) (p - t->size)) >> 31;
727
728 prefetch(&t->tree[p]);
729
730 j = n;
731 f = &t->tree[j];
732
733 /*
734 * n = (f->mantissa > bfloat_mantissa())
735 * ? j * 2
736 * : j * 2 + 1;
737 *
738 * We need to subtract 1 from f->mantissa for the sign bit trick
739 * to work - that's done in make_bfloat()
740 */
741 if (likely(f->exponent != 127))
742 n = j * 2 + (((unsigned)
743 (f->mantissa -
744 bfloat_mantissa(search, f))) >> 31);
745 else
746 n = (bkey_cmp(tree_to_bkey(t, j), search) > 0)
747 ? j * 2
748 : j * 2 + 1;
749 } while (n < t->size);
750
751 inorder = to_inorder(j, t);
752
753 /*
754 * n would have been the node we recursed to - the low bit tells us if
755 * we recursed left or recursed right.
756 */
757 if (n & 1) {
758 l = cacheline_to_bkey(t, inorder, f->m);
759
760 if (++inorder != t->size) {
761 f = &t->tree[inorder_next(j, t->size)];
762 r = cacheline_to_bkey(t, inorder, f->m);
763 } else
764 r = end(t->data);
765 } else {
766 r = cacheline_to_bkey(t, inorder, f->m);
767
768 if (--inorder) {
769 f = &t->tree[inorder_prev(j, t->size)];
770 l = cacheline_to_bkey(t, inorder, f->m);
771 } else
772 l = t->data->start;
773 }
774
775 return (struct bset_search_iter) {l, r};
776}
777
778struct bkey *__bch_bset_search(struct btree *b, struct bset_tree *t,
779 const struct bkey *search)
780{
781 struct bset_search_iter i;
782
783 /*
784 * First, we search for a cacheline, then lastly we do a linear search
785 * within that cacheline.
786 *
787 * To search for the cacheline, there's three different possibilities:
788 * * The set is too small to have a search tree, so we just do a linear
789 * search over the whole set.
790 * * The set is the one we're currently inserting into; keeping a full
791 * auxiliary search tree up to date would be too expensive, so we
792 * use a much simpler lookup table to do a binary search -
793 * bset_search_write_set().
794 * * Or we use the auxiliary search tree we constructed earlier -
795 * bset_search_tree()
796 */
797
798 if (unlikely(!t->size)) {
799 i.l = t->data->start;
800 i.r = end(t->data);
801 } else if (bset_written(b, t)) {
802 /*
803 * Each node in the auxiliary search tree covers a certain range
804 * of bits, and keys above and below the set it covers might
805 * differ outside those bits - so we have to special case the
806 * start and end - handle that here:
807 */
808
809 if (unlikely(bkey_cmp(search, &t->end) >= 0))
810 return end(t->data);
811
812 if (unlikely(bkey_cmp(search, t->data->start) < 0))
813 return t->data->start;
814
815 i = bset_search_tree(b, t, search);
816 } else
817 i = bset_search_write_set(b, t, search);
818
819#ifdef CONFIG_BCACHE_EDEBUG
820 BUG_ON(bset_written(b, t) &&
821 i.l != t->data->start &&
822 bkey_cmp(tree_to_prev_bkey(t,
823 inorder_to_tree(bkey_to_cacheline(t, i.l), t)),
824 search) > 0);
825
826 BUG_ON(i.r != end(t->data) &&
827 bkey_cmp(i.r, search) <= 0);
828#endif
829
830 while (likely(i.l != i.r) &&
831 bkey_cmp(i.l, search) <= 0)
832 i.l = bkey_next(i.l);
833
834 return i.l;
835}
836
837/* Btree iterator */
838
839static inline bool btree_iter_cmp(struct btree_iter_set l,
840 struct btree_iter_set r)
841{
842 int64_t c = bkey_cmp(&START_KEY(l.k), &START_KEY(r.k));
843
844 return c ? c > 0 : l.k < r.k;
845}
846
847static inline bool btree_iter_end(struct btree_iter *iter)
848{
849 return !iter->used;
850}
851
852void bch_btree_iter_push(struct btree_iter *iter, struct bkey *k,
853 struct bkey *end)
854{
855 if (k != end)
856 BUG_ON(!heap_add(iter,
857 ((struct btree_iter_set) { k, end }),
858 btree_iter_cmp));
859}
860
861struct bkey *__bch_btree_iter_init(struct btree *b, struct btree_iter *iter,
862 struct bkey *search, struct bset_tree *start)
863{
864 struct bkey *ret = NULL;
865 iter->size = ARRAY_SIZE(iter->data);
866 iter->used = 0;
867
868 for (; start <= &b->sets[b->nsets]; start++) {
869 ret = bch_bset_search(b, start, search);
870 bch_btree_iter_push(iter, ret, end(start->data));
871 }
872
873 return ret;
874}
875
876struct bkey *bch_btree_iter_next(struct btree_iter *iter)
877{
878 struct btree_iter_set unused;
879 struct bkey *ret = NULL;
880
881 if (!btree_iter_end(iter)) {
882 ret = iter->data->k;
883 iter->data->k = bkey_next(iter->data->k);
884
885 if (iter->data->k > iter->data->end) {
Kent Overstreetcc0f4ea2013-03-27 12:47:45 -0700886 WARN_ONCE(1, "bset was corrupt!\n");
Kent Overstreetcafe5632013-03-23 16:11:31 -0700887 iter->data->k = iter->data->end;
888 }
889
890 if (iter->data->k == iter->data->end)
891 heap_pop(iter, unused, btree_iter_cmp);
892 else
893 heap_sift(iter, 0, btree_iter_cmp);
894 }
895
896 return ret;
897}
898
899struct bkey *bch_btree_iter_next_filter(struct btree_iter *iter,
900 struct btree *b, ptr_filter_fn fn)
901{
902 struct bkey *ret;
903
904 do {
905 ret = bch_btree_iter_next(iter);
906 } while (ret && fn(b, ret));
907
908 return ret;
909}
910
911struct bkey *bch_next_recurse_key(struct btree *b, struct bkey *search)
912{
913 struct btree_iter iter;
914
915 bch_btree_iter_init(b, &iter, search);
916 return bch_btree_iter_next_filter(&iter, b, bch_ptr_bad);
917}
918
919/* Mergesort */
920
921static void btree_sort_fixup(struct btree_iter *iter)
922{
923 while (iter->used > 1) {
924 struct btree_iter_set *top = iter->data, *i = top + 1;
925 struct bkey *k;
926
927 if (iter->used > 2 &&
928 btree_iter_cmp(i[0], i[1]))
929 i++;
930
931 for (k = i->k;
932 k != i->end && bkey_cmp(top->k, &START_KEY(k)) > 0;
933 k = bkey_next(k))
934 if (top->k > i->k)
935 __bch_cut_front(top->k, k);
936 else if (KEY_SIZE(k))
937 bch_cut_back(&START_KEY(k), top->k);
938
939 if (top->k < i->k || k == i->k)
940 break;
941
942 heap_sift(iter, i - top, btree_iter_cmp);
943 }
944}
945
946static void btree_mergesort(struct btree *b, struct bset *out,
947 struct btree_iter *iter,
948 bool fixup, bool remove_stale)
949{
950 struct bkey *k, *last = NULL;
951 bool (*bad)(struct btree *, const struct bkey *) = remove_stale
952 ? bch_ptr_bad
953 : bch_ptr_invalid;
954
955 while (!btree_iter_end(iter)) {
956 if (fixup && !b->level)
957 btree_sort_fixup(iter);
958
959 k = bch_btree_iter_next(iter);
960 if (bad(b, k))
961 continue;
962
963 if (!last) {
964 last = out->start;
965 bkey_copy(last, k);
966 } else if (b->level ||
967 !bch_bkey_try_merge(b, last, k)) {
968 last = bkey_next(last);
969 bkey_copy(last, k);
970 }
971 }
972
973 out->keys = last ? (uint64_t *) bkey_next(last) - out->d : 0;
974
975 pr_debug("sorted %i keys", out->keys);
976 bch_check_key_order(b, out);
977}
978
979static void __btree_sort(struct btree *b, struct btree_iter *iter,
980 unsigned start, unsigned order, bool fixup)
981{
982 uint64_t start_time;
983 bool remove_stale = !b->written;
984 struct bset *out = (void *) __get_free_pages(__GFP_NOWARN|GFP_NOIO,
985 order);
986 if (!out) {
987 mutex_lock(&b->c->sort_lock);
988 out = b->c->sort;
989 order = ilog2(bucket_pages(b->c));
990 }
991
992 start_time = local_clock();
993
994 btree_mergesort(b, out, iter, fixup, remove_stale);
995 b->nsets = start;
996
997 if (!fixup && !start && b->written)
998 bch_btree_verify(b, out);
999
1000 if (!start && order == b->page_order) {
1001 /*
1002 * Our temporary buffer is the same size as the btree node's
1003 * buffer, we can just swap buffers instead of doing a big
1004 * memcpy()
1005 */
1006
1007 out->magic = bset_magic(b->c);
1008 out->seq = b->sets[0].data->seq;
1009 out->version = b->sets[0].data->version;
1010 swap(out, b->sets[0].data);
1011
1012 if (b->c->sort == b->sets[0].data)
1013 b->c->sort = out;
1014 } else {
1015 b->sets[start].data->keys = out->keys;
1016 memcpy(b->sets[start].data->start, out->start,
1017 (void *) end(out) - (void *) out->start);
1018 }
1019
1020 if (out == b->c->sort)
1021 mutex_unlock(&b->c->sort_lock);
1022 else
1023 free_pages((unsigned long) out, order);
1024
1025 if (b->written)
1026 bset_build_written_tree(b);
1027
1028 if (!start) {
1029 spin_lock(&b->c->sort_time_lock);
Kent Overstreet169ef1c2013-03-28 12:50:55 -06001030 bch_time_stats_update(&b->c->sort_time, start_time);
Kent Overstreetcafe5632013-03-23 16:11:31 -07001031 spin_unlock(&b->c->sort_time_lock);
1032 }
1033}
1034
1035void bch_btree_sort_partial(struct btree *b, unsigned start)
1036{
1037 size_t oldsize = 0, order = b->page_order, keys = 0;
1038 struct btree_iter iter;
1039 __bch_btree_iter_init(b, &iter, NULL, &b->sets[start]);
1040
1041 BUG_ON(b->sets[b->nsets].data == write_block(b) &&
1042 (b->sets[b->nsets].size || b->nsets));
1043
1044 if (b->written)
1045 oldsize = bch_count_data(b);
1046
1047 if (start) {
1048 unsigned i;
1049
1050 for (i = start; i <= b->nsets; i++)
1051 keys += b->sets[i].data->keys;
1052
Kent Overstreetb1a67b02013-03-25 11:46:44 -07001053 order = roundup_pow_of_two(__set_bytes(b->sets->data,
1054 keys)) / PAGE_SIZE;
Kent Overstreetcafe5632013-03-23 16:11:31 -07001055 if (order)
1056 order = ilog2(order);
1057 }
1058
1059 __btree_sort(b, &iter, start, order, false);
1060
1061 EBUG_ON(b->written && bch_count_data(b) != oldsize);
1062}
1063
1064void bch_btree_sort_and_fix_extents(struct btree *b, struct btree_iter *iter)
1065{
1066 BUG_ON(!b->written);
1067 __btree_sort(b, iter, 0, b->page_order, true);
1068}
1069
1070void bch_btree_sort_into(struct btree *b, struct btree *new)
1071{
1072 uint64_t start_time = local_clock();
1073
1074 struct btree_iter iter;
1075 bch_btree_iter_init(b, &iter, NULL);
1076
1077 btree_mergesort(b, new->sets->data, &iter, false, true);
1078
1079 spin_lock(&b->c->sort_time_lock);
Kent Overstreet169ef1c2013-03-28 12:50:55 -06001080 bch_time_stats_update(&b->c->sort_time, start_time);
Kent Overstreetcafe5632013-03-23 16:11:31 -07001081 spin_unlock(&b->c->sort_time_lock);
1082
1083 bkey_copy_key(&new->key, &b->key);
1084 new->sets->size = 0;
1085}
1086
1087void bch_btree_sort_lazy(struct btree *b)
1088{
1089 if (b->nsets) {
1090 unsigned i, j, keys = 0, total;
1091
1092 for (i = 0; i <= b->nsets; i++)
1093 keys += b->sets[i].data->keys;
1094
1095 total = keys;
1096
1097 for (j = 0; j < b->nsets; j++) {
1098 if (keys * 2 < total ||
1099 keys < 1000) {
1100 bch_btree_sort_partial(b, j);
1101 return;
1102 }
1103
1104 keys -= b->sets[j].data->keys;
1105 }
1106
1107 /* Must sort if b->nsets == 3 or we'll overflow */
1108 if (b->nsets >= (MAX_BSETS - 1) - b->level) {
1109 bch_btree_sort(b);
1110 return;
1111 }
1112 }
1113
1114 bset_build_written_tree(b);
1115}
1116
1117/* Sysfs stuff */
1118
1119struct bset_stats {
1120 size_t nodes;
1121 size_t sets_written, sets_unwritten;
1122 size_t bytes_written, bytes_unwritten;
1123 size_t floats, failed;
1124};
1125
1126static int bch_btree_bset_stats(struct btree *b, struct btree_op *op,
1127 struct bset_stats *stats)
1128{
1129 struct bkey *k;
1130 unsigned i;
1131
1132 stats->nodes++;
1133
1134 for (i = 0; i <= b->nsets; i++) {
1135 struct bset_tree *t = &b->sets[i];
1136 size_t bytes = t->data->keys * sizeof(uint64_t);
1137 size_t j;
1138
1139 if (bset_written(b, t)) {
1140 stats->sets_written++;
1141 stats->bytes_written += bytes;
1142
1143 stats->floats += t->size - 1;
1144
1145 for (j = 1; j < t->size; j++)
1146 if (t->tree[j].exponent == 127)
1147 stats->failed++;
1148 } else {
1149 stats->sets_unwritten++;
1150 stats->bytes_unwritten += bytes;
1151 }
1152 }
1153
1154 if (b->level) {
1155 struct btree_iter iter;
1156
1157 for_each_key_filter(b, k, &iter, bch_ptr_bad) {
1158 int ret = btree(bset_stats, k, b, op, stats);
1159 if (ret)
1160 return ret;
1161 }
1162 }
1163
1164 return 0;
1165}
1166
1167int bch_bset_print_stats(struct cache_set *c, char *buf)
1168{
1169 struct btree_op op;
1170 struct bset_stats t;
1171 int ret;
1172
1173 bch_btree_op_init_stack(&op);
1174 memset(&t, 0, sizeof(struct bset_stats));
1175
1176 ret = btree_root(bset_stats, c, &op, &t);
1177 if (ret)
1178 return ret;
1179
1180 return snprintf(buf, PAGE_SIZE,
1181 "btree nodes: %zu\n"
1182 "written sets: %zu\n"
1183 "unwritten sets: %zu\n"
1184 "written key bytes: %zu\n"
1185 "unwritten key bytes: %zu\n"
1186 "floats: %zu\n"
1187 "failed: %zu\n",
1188 t.nodes,
1189 t.sets_written, t.sets_unwritten,
1190 t.bytes_written, t.bytes_unwritten,
1191 t.floats, t.failed);
1192}