blob: 4dc9cb4efacb4aa51495b41b729e4ed04815bc9d [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>
13
14/* Keylists */
15
16void bch_keylist_copy(struct keylist *dest, struct keylist *src)
17{
18 *dest = *src;
19
20 if (src->list == src->d) {
21 size_t n = (uint64_t *) src->top - src->d;
22 dest->top = (struct bkey *) &dest->d[n];
23 dest->list = dest->d;
24 }
25}
26
27int bch_keylist_realloc(struct keylist *l, int nptrs, struct cache_set *c)
28{
29 unsigned oldsize = (uint64_t *) l->top - l->list;
30 unsigned newsize = oldsize + 2 + nptrs;
31 uint64_t *new;
32
33 /* The journalling code doesn't handle the case where the keys to insert
34 * is bigger than an empty write: If we just return -ENOMEM here,
35 * bio_insert() and bio_invalidate() will insert the keys created so far
36 * and finish the rest when the keylist is empty.
37 */
38 if (newsize * sizeof(uint64_t) > block_bytes(c) - sizeof(struct jset))
39 return -ENOMEM;
40
41 newsize = roundup_pow_of_two(newsize);
42
43 if (newsize <= KEYLIST_INLINE ||
44 roundup_pow_of_two(oldsize) == newsize)
45 return 0;
46
47 new = krealloc(l->list == l->d ? NULL : l->list,
48 sizeof(uint64_t) * newsize, GFP_NOIO);
49
50 if (!new)
51 return -ENOMEM;
52
53 if (l->list == l->d)
54 memcpy(new, l->list, sizeof(uint64_t) * KEYLIST_INLINE);
55
56 l->list = new;
57 l->top = (struct bkey *) (&l->list[oldsize]);
58
59 return 0;
60}
61
62struct bkey *bch_keylist_pop(struct keylist *l)
63{
64 struct bkey *k = l->bottom;
65
66 if (k == l->top)
67 return NULL;
68
69 while (bkey_next(k) != l->top)
70 k = bkey_next(k);
71
72 return l->top = k;
73}
74
75/* Pointer validation */
76
77bool __bch_ptr_invalid(struct cache_set *c, int level, const struct bkey *k)
78{
79 unsigned i;
80
81 if (level && (!KEY_PTRS(k) || !KEY_SIZE(k) || KEY_DIRTY(k)))
82 goto bad;
83
84 if (!level && KEY_SIZE(k) > KEY_OFFSET(k))
85 goto bad;
86
87 if (!KEY_SIZE(k))
88 return true;
89
90 for (i = 0; i < KEY_PTRS(k); i++)
91 if (ptr_available(c, k, i)) {
92 struct cache *ca = PTR_CACHE(c, k, i);
93 size_t bucket = PTR_BUCKET_NR(c, k, i);
94 size_t r = bucket_remainder(c, PTR_OFFSET(k, i));
95
96 if (KEY_SIZE(k) + r > c->sb.bucket_size ||
97 bucket < ca->sb.first_bucket ||
98 bucket >= ca->sb.nbuckets)
99 goto bad;
100 }
101
102 return false;
103bad:
104 cache_bug(c, "spotted bad key %s: %s", pkey(k), bch_ptr_status(c, k));
105 return true;
106}
107
108bool bch_ptr_bad(struct btree *b, const struct bkey *k)
109{
110 struct bucket *g;
111 unsigned i, stale;
112
113 if (!bkey_cmp(k, &ZERO_KEY) ||
114 !KEY_PTRS(k) ||
115 bch_ptr_invalid(b, k))
116 return true;
117
118 if (KEY_PTRS(k) && PTR_DEV(k, 0) == PTR_CHECK_DEV)
119 return true;
120
121 for (i = 0; i < KEY_PTRS(k); i++)
122 if (ptr_available(b->c, k, i)) {
123 g = PTR_BUCKET(b->c, k, i);
124 stale = ptr_stale(b->c, k, i);
125
126 btree_bug_on(stale > 96, b,
127 "key too stale: %i, need_gc %u",
128 stale, b->c->need_gc);
129
130 btree_bug_on(stale && KEY_DIRTY(k) && KEY_SIZE(k),
131 b, "stale dirty pointer");
132
133 if (stale)
134 return true;
135
136#ifdef CONFIG_BCACHE_EDEBUG
137 if (!mutex_trylock(&b->c->bucket_lock))
138 continue;
139
140 if (b->level) {
141 if (KEY_DIRTY(k) ||
142 g->prio != BTREE_PRIO ||
143 (b->c->gc_mark_valid &&
144 GC_MARK(g) != GC_MARK_METADATA))
145 goto bug;
146
147 } else {
148 if (g->prio == BTREE_PRIO)
149 goto bug;
150
151 if (KEY_DIRTY(k) &&
152 b->c->gc_mark_valid &&
153 GC_MARK(g) != GC_MARK_DIRTY)
154 goto bug;
155 }
156 mutex_unlock(&b->c->bucket_lock);
157#endif
158 }
159
160 return false;
161#ifdef CONFIG_BCACHE_EDEBUG
162bug:
163 mutex_unlock(&b->c->bucket_lock);
Kent Overstreetb1a67b02013-03-25 11:46:44 -0700164 btree_bug(b,
165"inconsistent pointer %s: bucket %zu pin %i prio %i gen %i last_gc %i mark %llu gc_gen %i",
166 pkey(k), PTR_BUCKET_NR(b->c, k, i), atomic_read(&g->pin),
Kent Overstreetcafe5632013-03-23 16:11:31 -0700167 g->prio, g->gen, g->last_gc, GC_MARK(g), g->gc_gen);
168 return true;
169#endif
170}
171
172/* Key/pointer manipulation */
173
174void bch_bkey_copy_single_ptr(struct bkey *dest, const struct bkey *src,
175 unsigned i)
176{
177 BUG_ON(i > KEY_PTRS(src));
178
179 /* Only copy the header, key, and one pointer. */
180 memcpy(dest, src, 2 * sizeof(uint64_t));
181 dest->ptr[0] = src->ptr[i];
182 SET_KEY_PTRS(dest, 1);
183 /* We didn't copy the checksum so clear that bit. */
184 SET_KEY_CSUM(dest, 0);
185}
186
187bool __bch_cut_front(const struct bkey *where, struct bkey *k)
188{
189 unsigned i, len = 0;
190
191 if (bkey_cmp(where, &START_KEY(k)) <= 0)
192 return false;
193
194 if (bkey_cmp(where, k) < 0)
195 len = KEY_OFFSET(k) - KEY_OFFSET(where);
196 else
197 bkey_copy_key(k, where);
198
199 for (i = 0; i < KEY_PTRS(k); i++)
200 SET_PTR_OFFSET(k, i, PTR_OFFSET(k, i) + KEY_SIZE(k) - len);
201
202 BUG_ON(len > KEY_SIZE(k));
203 SET_KEY_SIZE(k, len);
204 return true;
205}
206
207bool __bch_cut_back(const struct bkey *where, struct bkey *k)
208{
209 unsigned len = 0;
210
211 if (bkey_cmp(where, k) >= 0)
212 return false;
213
214 BUG_ON(KEY_INODE(where) != KEY_INODE(k));
215
216 if (bkey_cmp(where, &START_KEY(k)) > 0)
217 len = KEY_OFFSET(where) - KEY_START(k);
218
219 bkey_copy_key(k, where);
220
221 BUG_ON(len > KEY_SIZE(k));
222 SET_KEY_SIZE(k, len);
223 return true;
224}
225
226static uint64_t merge_chksums(struct bkey *l, struct bkey *r)
227{
228 return (l->ptr[KEY_PTRS(l)] + r->ptr[KEY_PTRS(r)]) &
229 ~((uint64_t)1 << 63);
230}
231
232/* Tries to merge l and r: l should be lower than r
233 * Returns true if we were able to merge. If we did merge, l will be the merged
234 * key, r will be untouched.
235 */
236bool bch_bkey_try_merge(struct btree *b, struct bkey *l, struct bkey *r)
237{
238 unsigned i;
239
240 if (key_merging_disabled(b->c))
241 return false;
242
243 if (KEY_PTRS(l) != KEY_PTRS(r) ||
244 KEY_DIRTY(l) != KEY_DIRTY(r) ||
245 bkey_cmp(l, &START_KEY(r)))
246 return false;
247
248 for (i = 0; i < KEY_PTRS(l); i++)
249 if (l->ptr[i] + PTR(0, KEY_SIZE(l), 0) != r->ptr[i] ||
250 PTR_BUCKET_NR(b->c, l, i) != PTR_BUCKET_NR(b->c, r, i))
251 return false;
252
253 /* Keys with no pointers aren't restricted to one bucket and could
254 * overflow KEY_SIZE
255 */
256 if (KEY_SIZE(l) + KEY_SIZE(r) > USHRT_MAX) {
257 SET_KEY_OFFSET(l, KEY_OFFSET(l) + USHRT_MAX - KEY_SIZE(l));
258 SET_KEY_SIZE(l, USHRT_MAX);
259
260 bch_cut_front(l, r);
261 return false;
262 }
263
264 if (KEY_CSUM(l)) {
265 if (KEY_CSUM(r))
266 l->ptr[KEY_PTRS(l)] = merge_chksums(l, r);
267 else
268 SET_KEY_CSUM(l, 0);
269 }
270
271 SET_KEY_OFFSET(l, KEY_OFFSET(l) + KEY_SIZE(r));
272 SET_KEY_SIZE(l, KEY_SIZE(l) + KEY_SIZE(r));
273
274 return true;
275}
276
277/* Binary tree stuff for auxiliary search trees */
278
279static unsigned inorder_next(unsigned j, unsigned size)
280{
281 if (j * 2 + 1 < size) {
282 j = j * 2 + 1;
283
284 while (j * 2 < size)
285 j *= 2;
286 } else
287 j >>= ffz(j) + 1;
288
289 return j;
290}
291
292static unsigned inorder_prev(unsigned j, unsigned size)
293{
294 if (j * 2 < size) {
295 j = j * 2;
296
297 while (j * 2 + 1 < size)
298 j = j * 2 + 1;
299 } else
300 j >>= ffs(j);
301
302 return j;
303}
304
305/* I have no idea why this code works... and I'm the one who wrote it
306 *
307 * However, I do know what it does:
308 * Given a binary tree constructed in an array (i.e. how you normally implement
309 * a heap), it converts a node in the tree - referenced by array index - to the
310 * index it would have if you did an inorder traversal.
311 *
312 * Also tested for every j, size up to size somewhere around 6 million.
313 *
314 * The binary tree starts at array index 1, not 0
315 * extra is a function of size:
316 * extra = (size - rounddown_pow_of_two(size - 1)) << 1;
317 */
318static unsigned __to_inorder(unsigned j, unsigned size, unsigned extra)
319{
320 unsigned b = fls(j);
321 unsigned shift = fls(size - 1) - b;
322
323 j ^= 1U << (b - 1);
324 j <<= 1;
325 j |= 1;
326 j <<= shift;
327
328 if (j > extra)
329 j -= (j - extra) >> 1;
330
331 return j;
332}
333
334static unsigned to_inorder(unsigned j, struct bset_tree *t)
335{
336 return __to_inorder(j, t->size, t->extra);
337}
338
339static unsigned __inorder_to_tree(unsigned j, unsigned size, unsigned extra)
340{
341 unsigned shift;
342
343 if (j > extra)
344 j += j - extra;
345
346 shift = ffs(j);
347
348 j >>= shift;
349 j |= roundup_pow_of_two(size) >> shift;
350
351 return j;
352}
353
354static unsigned inorder_to_tree(unsigned j, struct bset_tree *t)
355{
356 return __inorder_to_tree(j, t->size, t->extra);
357}
358
359#if 0
360void inorder_test(void)
361{
362 unsigned long done = 0;
363 ktime_t start = ktime_get();
364
365 for (unsigned size = 2;
366 size < 65536000;
367 size++) {
368 unsigned extra = (size - rounddown_pow_of_two(size - 1)) << 1;
369 unsigned i = 1, j = rounddown_pow_of_two(size - 1);
370
371 if (!(size % 4096))
372 printk(KERN_NOTICE "loop %u, %llu per us\n", size,
373 done / ktime_us_delta(ktime_get(), start));
374
375 while (1) {
376 if (__inorder_to_tree(i, size, extra) != j)
377 panic("size %10u j %10u i %10u", size, j, i);
378
379 if (__to_inorder(j, size, extra) != i)
380 panic("size %10u j %10u i %10u", size, j, i);
381
382 if (j == rounddown_pow_of_two(size) - 1)
383 break;
384
385 BUG_ON(inorder_prev(inorder_next(j, size), size) != j);
386
387 j = inorder_next(j, size);
388 i++;
389 }
390
391 done += size - 1;
392 }
393}
394#endif
395
396/*
397 * Cacheline/offset <-> bkey pointer arithmatic:
398 *
399 * t->tree is a binary search tree in an array; each node corresponds to a key
400 * in one cacheline in t->set (BSET_CACHELINE bytes).
401 *
402 * This means we don't have to store the full index of the key that a node in
403 * the binary tree points to; to_inorder() gives us the cacheline, and then
404 * bkey_float->m gives us the offset within that cacheline, in units of 8 bytes.
405 *
406 * cacheline_to_bkey() and friends abstract out all the pointer arithmatic to
407 * make this work.
408 *
409 * To construct the bfloat for an arbitrary key we need to know what the key
410 * immediately preceding it is: we have to check if the two keys differ in the
411 * bits we're going to store in bkey_float->mantissa. t->prev[j] stores the size
412 * of the previous key so we can walk backwards to it from t->tree[j]'s key.
413 */
414
415static struct bkey *cacheline_to_bkey(struct bset_tree *t, unsigned cacheline,
416 unsigned offset)
417{
418 return ((void *) t->data) + cacheline * BSET_CACHELINE + offset * 8;
419}
420
421static unsigned bkey_to_cacheline(struct bset_tree *t, struct bkey *k)
422{
423 return ((void *) k - (void *) t->data) / BSET_CACHELINE;
424}
425
426static unsigned bkey_to_cacheline_offset(struct bkey *k)
427{
428 return ((size_t) k & (BSET_CACHELINE - 1)) / sizeof(uint64_t);
429}
430
431static struct bkey *tree_to_bkey(struct bset_tree *t, unsigned j)
432{
433 return cacheline_to_bkey(t, to_inorder(j, t), t->tree[j].m);
434}
435
436static struct bkey *tree_to_prev_bkey(struct bset_tree *t, unsigned j)
437{
438 return (void *) (((uint64_t *) tree_to_bkey(t, j)) - t->prev[j]);
439}
440
441/*
442 * For the write set - the one we're currently inserting keys into - we don't
443 * maintain a full search tree, we just keep a simple lookup table in t->prev.
444 */
445static struct bkey *table_to_bkey(struct bset_tree *t, unsigned cacheline)
446{
447 return cacheline_to_bkey(t, cacheline, t->prev[cacheline]);
448}
449
450static inline uint64_t shrd128(uint64_t high, uint64_t low, uint8_t shift)
451{
452#ifdef CONFIG_X86_64
453 asm("shrd %[shift],%[high],%[low]"
454 : [low] "+Rm" (low)
455 : [high] "R" (high),
456 [shift] "ci" (shift)
457 : "cc");
458#else
459 low >>= shift;
460 low |= (high << 1) << (63U - shift);
461#endif
462 return low;
463}
464
465static inline unsigned bfloat_mantissa(const struct bkey *k,
466 struct bkey_float *f)
467{
468 const uint64_t *p = &k->low - (f->exponent >> 6);
469 return shrd128(p[-1], p[0], f->exponent & 63) & BKEY_MANTISSA_MASK;
470}
471
472static void make_bfloat(struct bset_tree *t, unsigned j)
473{
474 struct bkey_float *f = &t->tree[j];
475 struct bkey *m = tree_to_bkey(t, j);
476 struct bkey *p = tree_to_prev_bkey(t, j);
477
478 struct bkey *l = is_power_of_2(j)
479 ? t->data->start
480 : tree_to_prev_bkey(t, j >> ffs(j));
481
482 struct bkey *r = is_power_of_2(j + 1)
483 ? node(t->data, t->data->keys - bkey_u64s(&t->end))
484 : tree_to_bkey(t, j >> (ffz(j) + 1));
485
486 BUG_ON(m < l || m > r);
487 BUG_ON(bkey_next(p) != m);
488
489 if (KEY_INODE(l) != KEY_INODE(r))
490 f->exponent = fls64(KEY_INODE(r) ^ KEY_INODE(l)) + 64;
491 else
492 f->exponent = fls64(r->low ^ l->low);
493
494 f->exponent = max_t(int, f->exponent - BKEY_MANTISSA_BITS, 0);
495
496 /*
497 * Setting f->exponent = 127 flags this node as failed, and causes the
498 * lookup code to fall back to comparing against the original key.
499 */
500
501 if (bfloat_mantissa(m, f) != bfloat_mantissa(p, f))
502 f->mantissa = bfloat_mantissa(m, f) - 1;
503 else
504 f->exponent = 127;
505}
506
507static void bset_alloc_tree(struct btree *b, struct bset_tree *t)
508{
509 if (t != b->sets) {
510 unsigned j = roundup(t[-1].size,
511 64 / sizeof(struct bkey_float));
512
513 t->tree = t[-1].tree + j;
514 t->prev = t[-1].prev + j;
515 }
516
517 while (t < b->sets + MAX_BSETS)
518 t++->size = 0;
519}
520
521static void bset_build_unwritten_tree(struct btree *b)
522{
523 struct bset_tree *t = b->sets + b->nsets;
524
525 bset_alloc_tree(b, t);
526
527 if (t->tree != b->sets->tree + bset_tree_space(b)) {
528 t->prev[0] = bkey_to_cacheline_offset(t->data->start);
529 t->size = 1;
530 }
531}
532
533static void bset_build_written_tree(struct btree *b)
534{
535 struct bset_tree *t = b->sets + b->nsets;
536 struct bkey *k = t->data->start;
537 unsigned j, cacheline = 1;
538
539 bset_alloc_tree(b, t);
540
541 t->size = min_t(unsigned,
542 bkey_to_cacheline(t, end(t->data)),
543 b->sets->tree + bset_tree_space(b) - t->tree);
544
545 if (t->size < 2) {
546 t->size = 0;
547 return;
548 }
549
550 t->extra = (t->size - rounddown_pow_of_two(t->size - 1)) << 1;
551
552 /* First we figure out where the first key in each cacheline is */
553 for (j = inorder_next(0, t->size);
554 j;
555 j = inorder_next(j, t->size)) {
556 while (bkey_to_cacheline(t, k) != cacheline)
557 k = bkey_next(k);
558
559 t->prev[j] = bkey_u64s(k);
560 k = bkey_next(k);
561 cacheline++;
562 t->tree[j].m = bkey_to_cacheline_offset(k);
563 }
564
565 while (bkey_next(k) != end(t->data))
566 k = bkey_next(k);
567
568 t->end = *k;
569
570 /* Then we build the tree */
571 for (j = inorder_next(0, t->size);
572 j;
573 j = inorder_next(j, t->size))
574 make_bfloat(t, j);
575}
576
577void bch_bset_fix_invalidated_key(struct btree *b, struct bkey *k)
578{
579 struct bset_tree *t;
580 unsigned inorder, j = 1;
581
582 for (t = b->sets; t <= &b->sets[b->nsets]; t++)
583 if (k < end(t->data))
584 goto found_set;
585
586 BUG();
587found_set:
588 if (!t->size || !bset_written(b, t))
589 return;
590
591 inorder = bkey_to_cacheline(t, k);
592
593 if (k == t->data->start)
594 goto fix_left;
595
596 if (bkey_next(k) == end(t->data)) {
597 t->end = *k;
598 goto fix_right;
599 }
600
601 j = inorder_to_tree(inorder, t);
602
603 if (j &&
604 j < t->size &&
605 k == tree_to_bkey(t, j))
606fix_left: do {
607 make_bfloat(t, j);
608 j = j * 2;
609 } while (j < t->size);
610
611 j = inorder_to_tree(inorder + 1, t);
612
613 if (j &&
614 j < t->size &&
615 k == tree_to_prev_bkey(t, j))
616fix_right: do {
617 make_bfloat(t, j);
618 j = j * 2 + 1;
619 } while (j < t->size);
620}
621
622void bch_bset_fix_lookup_table(struct btree *b, struct bkey *k)
623{
624 struct bset_tree *t = &b->sets[b->nsets];
625 unsigned shift = bkey_u64s(k);
626 unsigned j = bkey_to_cacheline(t, k);
627
628 /* We're getting called from btree_split() or btree_gc, just bail out */
629 if (!t->size)
630 return;
631
632 /* k is the key we just inserted; we need to find the entry in the
633 * lookup table for the first key that is strictly greater than k:
634 * it's either k's cacheline or the next one
635 */
636 if (j < t->size &&
637 table_to_bkey(t, j) <= k)
638 j++;
639
640 /* Adjust all the lookup table entries, and find a new key for any that
641 * have gotten too big
642 */
643 for (; j < t->size; j++) {
644 t->prev[j] += shift;
645
646 if (t->prev[j] > 7) {
647 k = table_to_bkey(t, j - 1);
648
649 while (k < cacheline_to_bkey(t, j, 0))
650 k = bkey_next(k);
651
652 t->prev[j] = bkey_to_cacheline_offset(k);
653 }
654 }
655
656 if (t->size == b->sets->tree + bset_tree_space(b) - t->tree)
657 return;
658
659 /* Possibly add a new entry to the end of the lookup table */
660
661 for (k = table_to_bkey(t, t->size - 1);
662 k != end(t->data);
663 k = bkey_next(k))
664 if (t->size == bkey_to_cacheline(t, k)) {
665 t->prev[t->size] = bkey_to_cacheline_offset(k);
666 t->size++;
667 }
668}
669
670void bch_bset_init_next(struct btree *b)
671{
672 struct bset *i = write_block(b);
673
674 if (i != b->sets[0].data) {
675 b->sets[++b->nsets].data = i;
676 i->seq = b->sets[0].data->seq;
677 } else
678 get_random_bytes(&i->seq, sizeof(uint64_t));
679
680 i->magic = bset_magic(b->c);
681 i->version = 0;
682 i->keys = 0;
683
684 bset_build_unwritten_tree(b);
685}
686
687struct bset_search_iter {
688 struct bkey *l, *r;
689};
690
691static struct bset_search_iter bset_search_write_set(struct btree *b,
692 struct bset_tree *t,
693 const struct bkey *search)
694{
695 unsigned li = 0, ri = t->size;
696
697 BUG_ON(!b->nsets &&
698 t->size < bkey_to_cacheline(t, end(t->data)));
699
700 while (li + 1 != ri) {
701 unsigned m = (li + ri) >> 1;
702
703 if (bkey_cmp(table_to_bkey(t, m), search) > 0)
704 ri = m;
705 else
706 li = m;
707 }
708
709 return (struct bset_search_iter) {
710 table_to_bkey(t, li),
711 ri < t->size ? table_to_bkey(t, ri) : end(t->data)
712 };
713}
714
715static struct bset_search_iter bset_search_tree(struct btree *b,
716 struct bset_tree *t,
717 const struct bkey *search)
718{
719 struct bkey *l, *r;
720 struct bkey_float *f;
721 unsigned inorder, j, n = 1;
722
723 do {
724 unsigned p = n << 4;
725 p &= ((int) (p - t->size)) >> 31;
726
727 prefetch(&t->tree[p]);
728
729 j = n;
730 f = &t->tree[j];
731
732 /*
733 * n = (f->mantissa > bfloat_mantissa())
734 * ? j * 2
735 * : j * 2 + 1;
736 *
737 * We need to subtract 1 from f->mantissa for the sign bit trick
738 * to work - that's done in make_bfloat()
739 */
740 if (likely(f->exponent != 127))
741 n = j * 2 + (((unsigned)
742 (f->mantissa -
743 bfloat_mantissa(search, f))) >> 31);
744 else
745 n = (bkey_cmp(tree_to_bkey(t, j), search) > 0)
746 ? j * 2
747 : j * 2 + 1;
748 } while (n < t->size);
749
750 inorder = to_inorder(j, t);
751
752 /*
753 * n would have been the node we recursed to - the low bit tells us if
754 * we recursed left or recursed right.
755 */
756 if (n & 1) {
757 l = cacheline_to_bkey(t, inorder, f->m);
758
759 if (++inorder != t->size) {
760 f = &t->tree[inorder_next(j, t->size)];
761 r = cacheline_to_bkey(t, inorder, f->m);
762 } else
763 r = end(t->data);
764 } else {
765 r = cacheline_to_bkey(t, inorder, f->m);
766
767 if (--inorder) {
768 f = &t->tree[inorder_prev(j, t->size)];
769 l = cacheline_to_bkey(t, inorder, f->m);
770 } else
771 l = t->data->start;
772 }
773
774 return (struct bset_search_iter) {l, r};
775}
776
777struct bkey *__bch_bset_search(struct btree *b, struct bset_tree *t,
778 const struct bkey *search)
779{
780 struct bset_search_iter i;
781
782 /*
783 * First, we search for a cacheline, then lastly we do a linear search
784 * within that cacheline.
785 *
786 * To search for the cacheline, there's three different possibilities:
787 * * The set is too small to have a search tree, so we just do a linear
788 * search over the whole set.
789 * * The set is the one we're currently inserting into; keeping a full
790 * auxiliary search tree up to date would be too expensive, so we
791 * use a much simpler lookup table to do a binary search -
792 * bset_search_write_set().
793 * * Or we use the auxiliary search tree we constructed earlier -
794 * bset_search_tree()
795 */
796
797 if (unlikely(!t->size)) {
798 i.l = t->data->start;
799 i.r = end(t->data);
800 } else if (bset_written(b, t)) {
801 /*
802 * Each node in the auxiliary search tree covers a certain range
803 * of bits, and keys above and below the set it covers might
804 * differ outside those bits - so we have to special case the
805 * start and end - handle that here:
806 */
807
808 if (unlikely(bkey_cmp(search, &t->end) >= 0))
809 return end(t->data);
810
811 if (unlikely(bkey_cmp(search, t->data->start) < 0))
812 return t->data->start;
813
814 i = bset_search_tree(b, t, search);
815 } else
816 i = bset_search_write_set(b, t, search);
817
818#ifdef CONFIG_BCACHE_EDEBUG
819 BUG_ON(bset_written(b, t) &&
820 i.l != t->data->start &&
821 bkey_cmp(tree_to_prev_bkey(t,
822 inorder_to_tree(bkey_to_cacheline(t, i.l), t)),
823 search) > 0);
824
825 BUG_ON(i.r != end(t->data) &&
826 bkey_cmp(i.r, search) <= 0);
827#endif
828
829 while (likely(i.l != i.r) &&
830 bkey_cmp(i.l, search) <= 0)
831 i.l = bkey_next(i.l);
832
833 return i.l;
834}
835
836/* Btree iterator */
837
838static inline bool btree_iter_cmp(struct btree_iter_set l,
839 struct btree_iter_set r)
840{
841 int64_t c = bkey_cmp(&START_KEY(l.k), &START_KEY(r.k));
842
843 return c ? c > 0 : l.k < r.k;
844}
845
846static inline bool btree_iter_end(struct btree_iter *iter)
847{
848 return !iter->used;
849}
850
851void bch_btree_iter_push(struct btree_iter *iter, struct bkey *k,
852 struct bkey *end)
853{
854 if (k != end)
855 BUG_ON(!heap_add(iter,
856 ((struct btree_iter_set) { k, end }),
857 btree_iter_cmp));
858}
859
860struct bkey *__bch_btree_iter_init(struct btree *b, struct btree_iter *iter,
861 struct bkey *search, struct bset_tree *start)
862{
863 struct bkey *ret = NULL;
864 iter->size = ARRAY_SIZE(iter->data);
865 iter->used = 0;
866
867 for (; start <= &b->sets[b->nsets]; start++) {
868 ret = bch_bset_search(b, start, search);
869 bch_btree_iter_push(iter, ret, end(start->data));
870 }
871
872 return ret;
873}
874
875struct bkey *bch_btree_iter_next(struct btree_iter *iter)
876{
877 struct btree_iter_set unused;
878 struct bkey *ret = NULL;
879
880 if (!btree_iter_end(iter)) {
881 ret = iter->data->k;
882 iter->data->k = bkey_next(iter->data->k);
883
884 if (iter->data->k > iter->data->end) {
885 __WARN();
886 iter->data->k = iter->data->end;
887 }
888
889 if (iter->data->k == iter->data->end)
890 heap_pop(iter, unused, btree_iter_cmp);
891 else
892 heap_sift(iter, 0, btree_iter_cmp);
893 }
894
895 return ret;
896}
897
898struct bkey *bch_btree_iter_next_filter(struct btree_iter *iter,
899 struct btree *b, ptr_filter_fn fn)
900{
901 struct bkey *ret;
902
903 do {
904 ret = bch_btree_iter_next(iter);
905 } while (ret && fn(b, ret));
906
907 return ret;
908}
909
910struct bkey *bch_next_recurse_key(struct btree *b, struct bkey *search)
911{
912 struct btree_iter iter;
913
914 bch_btree_iter_init(b, &iter, search);
915 return bch_btree_iter_next_filter(&iter, b, bch_ptr_bad);
916}
917
918/* Mergesort */
919
920static void btree_sort_fixup(struct btree_iter *iter)
921{
922 while (iter->used > 1) {
923 struct btree_iter_set *top = iter->data, *i = top + 1;
924 struct bkey *k;
925
926 if (iter->used > 2 &&
927 btree_iter_cmp(i[0], i[1]))
928 i++;
929
930 for (k = i->k;
931 k != i->end && bkey_cmp(top->k, &START_KEY(k)) > 0;
932 k = bkey_next(k))
933 if (top->k > i->k)
934 __bch_cut_front(top->k, k);
935 else if (KEY_SIZE(k))
936 bch_cut_back(&START_KEY(k), top->k);
937
938 if (top->k < i->k || k == i->k)
939 break;
940
941 heap_sift(iter, i - top, btree_iter_cmp);
942 }
943}
944
945static void btree_mergesort(struct btree *b, struct bset *out,
946 struct btree_iter *iter,
947 bool fixup, bool remove_stale)
948{
949 struct bkey *k, *last = NULL;
950 bool (*bad)(struct btree *, const struct bkey *) = remove_stale
951 ? bch_ptr_bad
952 : bch_ptr_invalid;
953
954 while (!btree_iter_end(iter)) {
955 if (fixup && !b->level)
956 btree_sort_fixup(iter);
957
958 k = bch_btree_iter_next(iter);
959 if (bad(b, k))
960 continue;
961
962 if (!last) {
963 last = out->start;
964 bkey_copy(last, k);
965 } else if (b->level ||
966 !bch_bkey_try_merge(b, last, k)) {
967 last = bkey_next(last);
968 bkey_copy(last, k);
969 }
970 }
971
972 out->keys = last ? (uint64_t *) bkey_next(last) - out->d : 0;
973
974 pr_debug("sorted %i keys", out->keys);
975 bch_check_key_order(b, out);
976}
977
978static void __btree_sort(struct btree *b, struct btree_iter *iter,
979 unsigned start, unsigned order, bool fixup)
980{
981 uint64_t start_time;
982 bool remove_stale = !b->written;
983 struct bset *out = (void *) __get_free_pages(__GFP_NOWARN|GFP_NOIO,
984 order);
985 if (!out) {
986 mutex_lock(&b->c->sort_lock);
987 out = b->c->sort;
988 order = ilog2(bucket_pages(b->c));
989 }
990
991 start_time = local_clock();
992
993 btree_mergesort(b, out, iter, fixup, remove_stale);
994 b->nsets = start;
995
996 if (!fixup && !start && b->written)
997 bch_btree_verify(b, out);
998
999 if (!start && order == b->page_order) {
1000 /*
1001 * Our temporary buffer is the same size as the btree node's
1002 * buffer, we can just swap buffers instead of doing a big
1003 * memcpy()
1004 */
1005
1006 out->magic = bset_magic(b->c);
1007 out->seq = b->sets[0].data->seq;
1008 out->version = b->sets[0].data->version;
1009 swap(out, b->sets[0].data);
1010
1011 if (b->c->sort == b->sets[0].data)
1012 b->c->sort = out;
1013 } else {
1014 b->sets[start].data->keys = out->keys;
1015 memcpy(b->sets[start].data->start, out->start,
1016 (void *) end(out) - (void *) out->start);
1017 }
1018
1019 if (out == b->c->sort)
1020 mutex_unlock(&b->c->sort_lock);
1021 else
1022 free_pages((unsigned long) out, order);
1023
1024 if (b->written)
1025 bset_build_written_tree(b);
1026
1027 if (!start) {
1028 spin_lock(&b->c->sort_time_lock);
1029 time_stats_update(&b->c->sort_time, start_time);
1030 spin_unlock(&b->c->sort_time_lock);
1031 }
1032}
1033
1034void bch_btree_sort_partial(struct btree *b, unsigned start)
1035{
1036 size_t oldsize = 0, order = b->page_order, keys = 0;
1037 struct btree_iter iter;
1038 __bch_btree_iter_init(b, &iter, NULL, &b->sets[start]);
1039
1040 BUG_ON(b->sets[b->nsets].data == write_block(b) &&
1041 (b->sets[b->nsets].size || b->nsets));
1042
1043 if (b->written)
1044 oldsize = bch_count_data(b);
1045
1046 if (start) {
1047 unsigned i;
1048
1049 for (i = start; i <= b->nsets; i++)
1050 keys += b->sets[i].data->keys;
1051
Kent Overstreetb1a67b02013-03-25 11:46:44 -07001052 order = roundup_pow_of_two(__set_bytes(b->sets->data,
1053 keys)) / PAGE_SIZE;
Kent Overstreetcafe5632013-03-23 16:11:31 -07001054 if (order)
1055 order = ilog2(order);
1056 }
1057
1058 __btree_sort(b, &iter, start, order, false);
1059
1060 EBUG_ON(b->written && bch_count_data(b) != oldsize);
1061}
1062
1063void bch_btree_sort_and_fix_extents(struct btree *b, struct btree_iter *iter)
1064{
1065 BUG_ON(!b->written);
1066 __btree_sort(b, iter, 0, b->page_order, true);
1067}
1068
1069void bch_btree_sort_into(struct btree *b, struct btree *new)
1070{
1071 uint64_t start_time = local_clock();
1072
1073 struct btree_iter iter;
1074 bch_btree_iter_init(b, &iter, NULL);
1075
1076 btree_mergesort(b, new->sets->data, &iter, false, true);
1077
1078 spin_lock(&b->c->sort_time_lock);
1079 time_stats_update(&b->c->sort_time, start_time);
1080 spin_unlock(&b->c->sort_time_lock);
1081
1082 bkey_copy_key(&new->key, &b->key);
1083 new->sets->size = 0;
1084}
1085
1086void bch_btree_sort_lazy(struct btree *b)
1087{
1088 if (b->nsets) {
1089 unsigned i, j, keys = 0, total;
1090
1091 for (i = 0; i <= b->nsets; i++)
1092 keys += b->sets[i].data->keys;
1093
1094 total = keys;
1095
1096 for (j = 0; j < b->nsets; j++) {
1097 if (keys * 2 < total ||
1098 keys < 1000) {
1099 bch_btree_sort_partial(b, j);
1100 return;
1101 }
1102
1103 keys -= b->sets[j].data->keys;
1104 }
1105
1106 /* Must sort if b->nsets == 3 or we'll overflow */
1107 if (b->nsets >= (MAX_BSETS - 1) - b->level) {
1108 bch_btree_sort(b);
1109 return;
1110 }
1111 }
1112
1113 bset_build_written_tree(b);
1114}
1115
1116/* Sysfs stuff */
1117
1118struct bset_stats {
1119 size_t nodes;
1120 size_t sets_written, sets_unwritten;
1121 size_t bytes_written, bytes_unwritten;
1122 size_t floats, failed;
1123};
1124
1125static int bch_btree_bset_stats(struct btree *b, struct btree_op *op,
1126 struct bset_stats *stats)
1127{
1128 struct bkey *k;
1129 unsigned i;
1130
1131 stats->nodes++;
1132
1133 for (i = 0; i <= b->nsets; i++) {
1134 struct bset_tree *t = &b->sets[i];
1135 size_t bytes = t->data->keys * sizeof(uint64_t);
1136 size_t j;
1137
1138 if (bset_written(b, t)) {
1139 stats->sets_written++;
1140 stats->bytes_written += bytes;
1141
1142 stats->floats += t->size - 1;
1143
1144 for (j = 1; j < t->size; j++)
1145 if (t->tree[j].exponent == 127)
1146 stats->failed++;
1147 } else {
1148 stats->sets_unwritten++;
1149 stats->bytes_unwritten += bytes;
1150 }
1151 }
1152
1153 if (b->level) {
1154 struct btree_iter iter;
1155
1156 for_each_key_filter(b, k, &iter, bch_ptr_bad) {
1157 int ret = btree(bset_stats, k, b, op, stats);
1158 if (ret)
1159 return ret;
1160 }
1161 }
1162
1163 return 0;
1164}
1165
1166int bch_bset_print_stats(struct cache_set *c, char *buf)
1167{
1168 struct btree_op op;
1169 struct bset_stats t;
1170 int ret;
1171
1172 bch_btree_op_init_stack(&op);
1173 memset(&t, 0, sizeof(struct bset_stats));
1174
1175 ret = btree_root(bset_stats, c, &op, &t);
1176 if (ret)
1177 return ret;
1178
1179 return snprintf(buf, PAGE_SIZE,
1180 "btree nodes: %zu\n"
1181 "written sets: %zu\n"
1182 "unwritten sets: %zu\n"
1183 "written key bytes: %zu\n"
1184 "unwritten key bytes: %zu\n"
1185 "floats: %zu\n"
1186 "failed: %zu\n",
1187 t.nodes,
1188 t.sets_written, t.sets_unwritten,
1189 t.bytes_written, t.bytes_unwritten,
1190 t.floats, t.failed);
1191}