Loading...
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Code for working with individual keys, and sorted sets of keys with in a
4 * btree node
5 *
6 * Copyright 2012 Google, Inc.
7 */
8
9#define pr_fmt(fmt) "bcache: %s() " fmt, __func__
10
11#include "util.h"
12#include "bset.h"
13
14#include <linux/console.h>
15#include <linux/sched/clock.h>
16#include <linux/random.h>
17#include <linux/prefetch.h>
18
19#ifdef CONFIG_BCACHE_DEBUG
20
21void bch_dump_bset(struct btree_keys *b, struct bset *i, unsigned int set)
22{
23 struct bkey *k, *next;
24
25 for (k = i->start; k < bset_bkey_last(i); k = next) {
26 next = bkey_next(k);
27
28 pr_err("block %u key %u/%u: ", set,
29 (unsigned int) ((u64 *) k - i->d), i->keys);
30
31 if (b->ops->key_dump)
32 b->ops->key_dump(b, k);
33 else
34 pr_cont("%llu:%llu\n", KEY_INODE(k), KEY_OFFSET(k));
35
36 if (next < bset_bkey_last(i) &&
37 bkey_cmp(k, b->ops->is_extents ?
38 &START_KEY(next) : next) > 0)
39 pr_err("Key skipped backwards\n");
40 }
41}
42
43void bch_dump_bucket(struct btree_keys *b)
44{
45 unsigned int i;
46
47 console_lock();
48 for (i = 0; i <= b->nsets; i++)
49 bch_dump_bset(b, b->set[i].data,
50 bset_sector_offset(b, b->set[i].data));
51 console_unlock();
52}
53
54int __bch_count_data(struct btree_keys *b)
55{
56 unsigned int ret = 0;
57 struct btree_iter iter;
58 struct bkey *k;
59
60 if (b->ops->is_extents)
61 for_each_key(b, k, &iter)
62 ret += KEY_SIZE(k);
63 return ret;
64}
65
66void __bch_check_keys(struct btree_keys *b, const char *fmt, ...)
67{
68 va_list args;
69 struct bkey *k, *p = NULL;
70 struct btree_iter iter;
71 const char *err;
72
73 for_each_key(b, k, &iter) {
74 if (b->ops->is_extents) {
75 err = "Keys out of order";
76 if (p && bkey_cmp(&START_KEY(p), &START_KEY(k)) > 0)
77 goto bug;
78
79 if (bch_ptr_invalid(b, k))
80 continue;
81
82 err = "Overlapping keys";
83 if (p && bkey_cmp(p, &START_KEY(k)) > 0)
84 goto bug;
85 } else {
86 if (bch_ptr_bad(b, k))
87 continue;
88
89 err = "Duplicate keys";
90 if (p && !bkey_cmp(p, k))
91 goto bug;
92 }
93 p = k;
94 }
95#if 0
96 err = "Key larger than btree node key";
97 if (p && bkey_cmp(p, &b->key) > 0)
98 goto bug;
99#endif
100 return;
101bug:
102 bch_dump_bucket(b);
103
104 va_start(args, fmt);
105 vprintk(fmt, args);
106 va_end(args);
107
108 panic("bch_check_keys error: %s:\n", err);
109}
110
111static void bch_btree_iter_next_check(struct btree_iter *iter)
112{
113 struct bkey *k = iter->data->k, *next = bkey_next(k);
114
115 if (next < iter->data->end &&
116 bkey_cmp(k, iter->b->ops->is_extents ?
117 &START_KEY(next) : next) > 0) {
118 bch_dump_bucket(iter->b);
119 panic("Key skipped backwards\n");
120 }
121}
122
123#else
124
125static inline void bch_btree_iter_next_check(struct btree_iter *iter) {}
126
127#endif
128
129/* Keylists */
130
131int __bch_keylist_realloc(struct keylist *l, unsigned int u64s)
132{
133 size_t oldsize = bch_keylist_nkeys(l);
134 size_t newsize = oldsize + u64s;
135 uint64_t *old_keys = l->keys_p == l->inline_keys ? NULL : l->keys_p;
136 uint64_t *new_keys;
137
138 newsize = roundup_pow_of_two(newsize);
139
140 if (newsize <= KEYLIST_INLINE ||
141 roundup_pow_of_two(oldsize) == newsize)
142 return 0;
143
144 new_keys = krealloc(old_keys, sizeof(uint64_t) * newsize, GFP_NOIO);
145
146 if (!new_keys)
147 return -ENOMEM;
148
149 if (!old_keys)
150 memcpy(new_keys, l->inline_keys, sizeof(uint64_t) * oldsize);
151
152 l->keys_p = new_keys;
153 l->top_p = new_keys + oldsize;
154
155 return 0;
156}
157
158/* Pop the top key of keylist by pointing l->top to its previous key */
159struct bkey *bch_keylist_pop(struct keylist *l)
160{
161 struct bkey *k = l->keys;
162
163 if (k == l->top)
164 return NULL;
165
166 while (bkey_next(k) != l->top)
167 k = bkey_next(k);
168
169 return l->top = k;
170}
171
172/* Pop the bottom key of keylist and update l->top_p */
173void bch_keylist_pop_front(struct keylist *l)
174{
175 l->top_p -= bkey_u64s(l->keys);
176
177 memmove(l->keys,
178 bkey_next(l->keys),
179 bch_keylist_bytes(l));
180}
181
182/* Key/pointer manipulation */
183
184void bch_bkey_copy_single_ptr(struct bkey *dest, const struct bkey *src,
185 unsigned int i)
186{
187 BUG_ON(i > KEY_PTRS(src));
188
189 /* Only copy the header, key, and one pointer. */
190 memcpy(dest, src, 2 * sizeof(uint64_t));
191 dest->ptr[0] = src->ptr[i];
192 SET_KEY_PTRS(dest, 1);
193 /* We didn't copy the checksum so clear that bit. */
194 SET_KEY_CSUM(dest, 0);
195}
196
197bool __bch_cut_front(const struct bkey *where, struct bkey *k)
198{
199 unsigned int i, len = 0;
200
201 if (bkey_cmp(where, &START_KEY(k)) <= 0)
202 return false;
203
204 if (bkey_cmp(where, k) < 0)
205 len = KEY_OFFSET(k) - KEY_OFFSET(where);
206 else
207 bkey_copy_key(k, where);
208
209 for (i = 0; i < KEY_PTRS(k); i++)
210 SET_PTR_OFFSET(k, i, PTR_OFFSET(k, i) + KEY_SIZE(k) - len);
211
212 BUG_ON(len > KEY_SIZE(k));
213 SET_KEY_SIZE(k, len);
214 return true;
215}
216
217bool __bch_cut_back(const struct bkey *where, struct bkey *k)
218{
219 unsigned int len = 0;
220
221 if (bkey_cmp(where, k) >= 0)
222 return false;
223
224 BUG_ON(KEY_INODE(where) != KEY_INODE(k));
225
226 if (bkey_cmp(where, &START_KEY(k)) > 0)
227 len = KEY_OFFSET(where) - KEY_START(k);
228
229 bkey_copy_key(k, where);
230
231 BUG_ON(len > KEY_SIZE(k));
232 SET_KEY_SIZE(k, len);
233 return true;
234}
235
236/* Auxiliary search trees */
237
238/* 32 bits total: */
239#define BKEY_MID_BITS 3
240#define BKEY_EXPONENT_BITS 7
241#define BKEY_MANTISSA_BITS (32 - BKEY_MID_BITS - BKEY_EXPONENT_BITS)
242#define BKEY_MANTISSA_MASK ((1 << BKEY_MANTISSA_BITS) - 1)
243
244struct bkey_float {
245 unsigned int exponent:BKEY_EXPONENT_BITS;
246 unsigned int m:BKEY_MID_BITS;
247 unsigned int mantissa:BKEY_MANTISSA_BITS;
248} __packed;
249
250/*
251 * BSET_CACHELINE was originally intended to match the hardware cacheline size -
252 * it used to be 64, but I realized the lookup code would touch slightly less
253 * memory if it was 128.
254 *
255 * It definites the number of bytes (in struct bset) per struct bkey_float in
256 * the auxiliar search tree - when we're done searching the bset_float tree we
257 * have this many bytes left that we do a linear search over.
258 *
259 * Since (after level 5) every level of the bset_tree is on a new cacheline,
260 * we're touching one fewer cacheline in the bset tree in exchange for one more
261 * cacheline in the linear search - but the linear search might stop before it
262 * gets to the second cacheline.
263 */
264
265#define BSET_CACHELINE 128
266
267/* Space required for the btree node keys */
268static inline size_t btree_keys_bytes(struct btree_keys *b)
269{
270 return PAGE_SIZE << b->page_order;
271}
272
273static inline size_t btree_keys_cachelines(struct btree_keys *b)
274{
275 return btree_keys_bytes(b) / BSET_CACHELINE;
276}
277
278/* Space required for the auxiliary search trees */
279static inline size_t bset_tree_bytes(struct btree_keys *b)
280{
281 return btree_keys_cachelines(b) * sizeof(struct bkey_float);
282}
283
284/* Space required for the prev pointers */
285static inline size_t bset_prev_bytes(struct btree_keys *b)
286{
287 return btree_keys_cachelines(b) * sizeof(uint8_t);
288}
289
290/* Memory allocation */
291
292void bch_btree_keys_free(struct btree_keys *b)
293{
294 struct bset_tree *t = b->set;
295
296 if (bset_prev_bytes(b) < PAGE_SIZE)
297 kfree(t->prev);
298 else
299 free_pages((unsigned long) t->prev,
300 get_order(bset_prev_bytes(b)));
301
302 if (bset_tree_bytes(b) < PAGE_SIZE)
303 kfree(t->tree);
304 else
305 free_pages((unsigned long) t->tree,
306 get_order(bset_tree_bytes(b)));
307
308 free_pages((unsigned long) t->data, b->page_order);
309
310 t->prev = NULL;
311 t->tree = NULL;
312 t->data = NULL;
313}
314
315int bch_btree_keys_alloc(struct btree_keys *b,
316 unsigned int page_order,
317 gfp_t gfp)
318{
319 struct bset_tree *t = b->set;
320
321 BUG_ON(t->data);
322
323 b->page_order = page_order;
324
325 t->data = (void *) __get_free_pages(__GFP_COMP|gfp, b->page_order);
326 if (!t->data)
327 goto err;
328
329 t->tree = bset_tree_bytes(b) < PAGE_SIZE
330 ? kmalloc(bset_tree_bytes(b), gfp)
331 : (void *) __get_free_pages(gfp, get_order(bset_tree_bytes(b)));
332 if (!t->tree)
333 goto err;
334
335 t->prev = bset_prev_bytes(b) < PAGE_SIZE
336 ? kmalloc(bset_prev_bytes(b), gfp)
337 : (void *) __get_free_pages(gfp, get_order(bset_prev_bytes(b)));
338 if (!t->prev)
339 goto err;
340
341 return 0;
342err:
343 bch_btree_keys_free(b);
344 return -ENOMEM;
345}
346
347void bch_btree_keys_init(struct btree_keys *b, const struct btree_keys_ops *ops,
348 bool *expensive_debug_checks)
349{
350 b->ops = ops;
351 b->expensive_debug_checks = expensive_debug_checks;
352 b->nsets = 0;
353 b->last_set_unwritten = 0;
354
355 /*
356 * struct btree_keys in embedded in struct btree, and struct
357 * bset_tree is embedded into struct btree_keys. They are all
358 * initialized as 0 by kzalloc() in mca_bucket_alloc(), and
359 * b->set[0].data is allocated in bch_btree_keys_alloc(), so we
360 * don't have to initiate b->set[].size and b->set[].data here
361 * any more.
362 */
363}
364
365/* Binary tree stuff for auxiliary search trees */
366
367/*
368 * return array index next to j when does in-order traverse
369 * of a binary tree which is stored in a linear array
370 */
371static unsigned int inorder_next(unsigned int j, unsigned int size)
372{
373 if (j * 2 + 1 < size) {
374 j = j * 2 + 1;
375
376 while (j * 2 < size)
377 j *= 2;
378 } else
379 j >>= ffz(j) + 1;
380
381 return j;
382}
383
384/*
385 * return array index previous to j when does in-order traverse
386 * of a binary tree which is stored in a linear array
387 */
388static unsigned int inorder_prev(unsigned int j, unsigned int size)
389{
390 if (j * 2 < size) {
391 j = j * 2;
392
393 while (j * 2 + 1 < size)
394 j = j * 2 + 1;
395 } else
396 j >>= ffs(j);
397
398 return j;
399}
400
401/*
402 * I have no idea why this code works... and I'm the one who wrote it
403 *
404 * However, I do know what it does:
405 * Given a binary tree constructed in an array (i.e. how you normally implement
406 * a heap), it converts a node in the tree - referenced by array index - to the
407 * index it would have if you did an inorder traversal.
408 *
409 * Also tested for every j, size up to size somewhere around 6 million.
410 *
411 * The binary tree starts at array index 1, not 0
412 * extra is a function of size:
413 * extra = (size - rounddown_pow_of_two(size - 1)) << 1;
414 */
415static unsigned int __to_inorder(unsigned int j,
416 unsigned int size,
417 unsigned int extra)
418{
419 unsigned int b = fls(j);
420 unsigned int shift = fls(size - 1) - b;
421
422 j ^= 1U << (b - 1);
423 j <<= 1;
424 j |= 1;
425 j <<= shift;
426
427 if (j > extra)
428 j -= (j - extra) >> 1;
429
430 return j;
431}
432
433/*
434 * Return the cacheline index in bset_tree->data, where j is index
435 * from a linear array which stores the auxiliar binary tree
436 */
437static unsigned int to_inorder(unsigned int j, struct bset_tree *t)
438{
439 return __to_inorder(j, t->size, t->extra);
440}
441
442static unsigned int __inorder_to_tree(unsigned int j,
443 unsigned int size,
444 unsigned int extra)
445{
446 unsigned int shift;
447
448 if (j > extra)
449 j += j - extra;
450
451 shift = ffs(j);
452
453 j >>= shift;
454 j |= roundup_pow_of_two(size) >> shift;
455
456 return j;
457}
458
459/*
460 * Return an index from a linear array which stores the auxiliar binary
461 * tree, j is the cacheline index of t->data.
462 */
463static unsigned int inorder_to_tree(unsigned int j, struct bset_tree *t)
464{
465 return __inorder_to_tree(j, t->size, t->extra);
466}
467
468#if 0
469void inorder_test(void)
470{
471 unsigned long done = 0;
472 ktime_t start = ktime_get();
473
474 for (unsigned int size = 2;
475 size < 65536000;
476 size++) {
477 unsigned int extra =
478 (size - rounddown_pow_of_two(size - 1)) << 1;
479 unsigned int i = 1, j = rounddown_pow_of_two(size - 1);
480
481 if (!(size % 4096))
482 pr_notice("loop %u, %llu per us\n", size,
483 done / ktime_us_delta(ktime_get(), start));
484
485 while (1) {
486 if (__inorder_to_tree(i, size, extra) != j)
487 panic("size %10u j %10u i %10u", size, j, i);
488
489 if (__to_inorder(j, size, extra) != i)
490 panic("size %10u j %10u i %10u", size, j, i);
491
492 if (j == rounddown_pow_of_two(size) - 1)
493 break;
494
495 BUG_ON(inorder_prev(inorder_next(j, size), size) != j);
496
497 j = inorder_next(j, size);
498 i++;
499 }
500
501 done += size - 1;
502 }
503}
504#endif
505
506/*
507 * Cacheline/offset <-> bkey pointer arithmetic:
508 *
509 * t->tree is a binary search tree in an array; each node corresponds to a key
510 * in one cacheline in t->set (BSET_CACHELINE bytes).
511 *
512 * This means we don't have to store the full index of the key that a node in
513 * the binary tree points to; to_inorder() gives us the cacheline, and then
514 * bkey_float->m gives us the offset within that cacheline, in units of 8 bytes.
515 *
516 * cacheline_to_bkey() and friends abstract out all the pointer arithmetic to
517 * make this work.
518 *
519 * To construct the bfloat for an arbitrary key we need to know what the key
520 * immediately preceding it is: we have to check if the two keys differ in the
521 * bits we're going to store in bkey_float->mantissa. t->prev[j] stores the size
522 * of the previous key so we can walk backwards to it from t->tree[j]'s key.
523 */
524
525static struct bkey *cacheline_to_bkey(struct bset_tree *t,
526 unsigned int cacheline,
527 unsigned int offset)
528{
529 return ((void *) t->data) + cacheline * BSET_CACHELINE + offset * 8;
530}
531
532static unsigned int bkey_to_cacheline(struct bset_tree *t, struct bkey *k)
533{
534 return ((void *) k - (void *) t->data) / BSET_CACHELINE;
535}
536
537static unsigned int bkey_to_cacheline_offset(struct bset_tree *t,
538 unsigned int cacheline,
539 struct bkey *k)
540{
541 return (u64 *) k - (u64 *) cacheline_to_bkey(t, cacheline, 0);
542}
543
544static struct bkey *tree_to_bkey(struct bset_tree *t, unsigned int j)
545{
546 return cacheline_to_bkey(t, to_inorder(j, t), t->tree[j].m);
547}
548
549static struct bkey *tree_to_prev_bkey(struct bset_tree *t, unsigned int j)
550{
551 return (void *) (((uint64_t *) tree_to_bkey(t, j)) - t->prev[j]);
552}
553
554/*
555 * For the write set - the one we're currently inserting keys into - we don't
556 * maintain a full search tree, we just keep a simple lookup table in t->prev.
557 */
558static struct bkey *table_to_bkey(struct bset_tree *t, unsigned int cacheline)
559{
560 return cacheline_to_bkey(t, cacheline, t->prev[cacheline]);
561}
562
563static inline uint64_t shrd128(uint64_t high, uint64_t low, uint8_t shift)
564{
565 low >>= shift;
566 low |= (high << 1) << (63U - shift);
567 return low;
568}
569
570/*
571 * Calculate mantissa value for struct bkey_float.
572 * If most significant bit of f->exponent is not set, then
573 * - f->exponent >> 6 is 0
574 * - p[0] points to bkey->low
575 * - p[-1] borrows bits from KEY_INODE() of bkey->high
576 * if most isgnificant bits of f->exponent is set, then
577 * - f->exponent >> 6 is 1
578 * - p[0] points to bits from KEY_INODE() of bkey->high
579 * - p[-1] points to other bits from KEY_INODE() of
580 * bkey->high too.
581 * See make_bfloat() to check when most significant bit of f->exponent
582 * is set or not.
583 */
584static inline unsigned int bfloat_mantissa(const struct bkey *k,
585 struct bkey_float *f)
586{
587 const uint64_t *p = &k->low - (f->exponent >> 6);
588
589 return shrd128(p[-1], p[0], f->exponent & 63) & BKEY_MANTISSA_MASK;
590}
591
592static void make_bfloat(struct bset_tree *t, unsigned int j)
593{
594 struct bkey_float *f = &t->tree[j];
595 struct bkey *m = tree_to_bkey(t, j);
596 struct bkey *p = tree_to_prev_bkey(t, j);
597
598 struct bkey *l = is_power_of_2(j)
599 ? t->data->start
600 : tree_to_prev_bkey(t, j >> ffs(j));
601
602 struct bkey *r = is_power_of_2(j + 1)
603 ? bset_bkey_idx(t->data, t->data->keys - bkey_u64s(&t->end))
604 : tree_to_bkey(t, j >> (ffz(j) + 1));
605
606 BUG_ON(m < l || m > r);
607 BUG_ON(bkey_next(p) != m);
608
609 /*
610 * If l and r have different KEY_INODE values (different backing
611 * device), f->exponent records how many least significant bits
612 * are different in KEY_INODE values and sets most significant
613 * bits to 1 (by +64).
614 * If l and r have same KEY_INODE value, f->exponent records
615 * how many different bits in least significant bits of bkey->low.
616 * See bfloat_mantiss() how the most significant bit of
617 * f->exponent is used to calculate bfloat mantissa value.
618 */
619 if (KEY_INODE(l) != KEY_INODE(r))
620 f->exponent = fls64(KEY_INODE(r) ^ KEY_INODE(l)) + 64;
621 else
622 f->exponent = fls64(r->low ^ l->low);
623
624 f->exponent = max_t(int, f->exponent - BKEY_MANTISSA_BITS, 0);
625
626 /*
627 * Setting f->exponent = 127 flags this node as failed, and causes the
628 * lookup code to fall back to comparing against the original key.
629 */
630
631 if (bfloat_mantissa(m, f) != bfloat_mantissa(p, f))
632 f->mantissa = bfloat_mantissa(m, f) - 1;
633 else
634 f->exponent = 127;
635}
636
637static void bset_alloc_tree(struct btree_keys *b, struct bset_tree *t)
638{
639 if (t != b->set) {
640 unsigned int j = roundup(t[-1].size,
641 64 / sizeof(struct bkey_float));
642
643 t->tree = t[-1].tree + j;
644 t->prev = t[-1].prev + j;
645 }
646
647 while (t < b->set + MAX_BSETS)
648 t++->size = 0;
649}
650
651static void bch_bset_build_unwritten_tree(struct btree_keys *b)
652{
653 struct bset_tree *t = bset_tree_last(b);
654
655 BUG_ON(b->last_set_unwritten);
656 b->last_set_unwritten = 1;
657
658 bset_alloc_tree(b, t);
659
660 if (t->tree != b->set->tree + btree_keys_cachelines(b)) {
661 t->prev[0] = bkey_to_cacheline_offset(t, 0, t->data->start);
662 t->size = 1;
663 }
664}
665
666void bch_bset_init_next(struct btree_keys *b, struct bset *i, uint64_t magic)
667{
668 if (i != b->set->data) {
669 b->set[++b->nsets].data = i;
670 i->seq = b->set->data->seq;
671 } else
672 get_random_bytes(&i->seq, sizeof(uint64_t));
673
674 i->magic = magic;
675 i->version = 0;
676 i->keys = 0;
677
678 bch_bset_build_unwritten_tree(b);
679}
680
681/*
682 * Build auxiliary binary tree 'struct bset_tree *t', this tree is used to
683 * accelerate bkey search in a btree node (pointed by bset_tree->data in
684 * memory). After search in the auxiliar tree by calling bset_search_tree(),
685 * a struct bset_search_iter is returned which indicates range [l, r] from
686 * bset_tree->data where the searching bkey might be inside. Then a followed
687 * linear comparison does the exact search, see __bch_bset_search() for how
688 * the auxiliary tree is used.
689 */
690void bch_bset_build_written_tree(struct btree_keys *b)
691{
692 struct bset_tree *t = bset_tree_last(b);
693 struct bkey *prev = NULL, *k = t->data->start;
694 unsigned int j, cacheline = 1;
695
696 b->last_set_unwritten = 0;
697
698 bset_alloc_tree(b, t);
699
700 t->size = min_t(unsigned int,
701 bkey_to_cacheline(t, bset_bkey_last(t->data)),
702 b->set->tree + btree_keys_cachelines(b) - t->tree);
703
704 if (t->size < 2) {
705 t->size = 0;
706 return;
707 }
708
709 t->extra = (t->size - rounddown_pow_of_two(t->size - 1)) << 1;
710
711 /* First we figure out where the first key in each cacheline is */
712 for (j = inorder_next(0, t->size);
713 j;
714 j = inorder_next(j, t->size)) {
715 while (bkey_to_cacheline(t, k) < cacheline) {
716 prev = k;
717 k = bkey_next(k);
718 }
719
720 t->prev[j] = bkey_u64s(prev);
721 t->tree[j].m = bkey_to_cacheline_offset(t, cacheline++, k);
722 }
723
724 while (bkey_next(k) != bset_bkey_last(t->data))
725 k = bkey_next(k);
726
727 t->end = *k;
728
729 /* Then we build the tree */
730 for (j = inorder_next(0, t->size);
731 j;
732 j = inorder_next(j, t->size))
733 make_bfloat(t, j);
734}
735
736/* Insert */
737
738void bch_bset_fix_invalidated_key(struct btree_keys *b, struct bkey *k)
739{
740 struct bset_tree *t;
741 unsigned int inorder, j = 1;
742
743 for (t = b->set; t <= bset_tree_last(b); t++)
744 if (k < bset_bkey_last(t->data))
745 goto found_set;
746
747 BUG();
748found_set:
749 if (!t->size || !bset_written(b, t))
750 return;
751
752 inorder = bkey_to_cacheline(t, k);
753
754 if (k == t->data->start)
755 goto fix_left;
756
757 if (bkey_next(k) == bset_bkey_last(t->data)) {
758 t->end = *k;
759 goto fix_right;
760 }
761
762 j = inorder_to_tree(inorder, t);
763
764 if (j &&
765 j < t->size &&
766 k == tree_to_bkey(t, j))
767fix_left: do {
768 make_bfloat(t, j);
769 j = j * 2;
770 } while (j < t->size);
771
772 j = inorder_to_tree(inorder + 1, t);
773
774 if (j &&
775 j < t->size &&
776 k == tree_to_prev_bkey(t, j))
777fix_right: do {
778 make_bfloat(t, j);
779 j = j * 2 + 1;
780 } while (j < t->size);
781}
782
783static void bch_bset_fix_lookup_table(struct btree_keys *b,
784 struct bset_tree *t,
785 struct bkey *k)
786{
787 unsigned int shift = bkey_u64s(k);
788 unsigned int j = bkey_to_cacheline(t, k);
789
790 /* We're getting called from btree_split() or btree_gc, just bail out */
791 if (!t->size)
792 return;
793
794 /*
795 * k is the key we just inserted; we need to find the entry in the
796 * lookup table for the first key that is strictly greater than k:
797 * it's either k's cacheline or the next one
798 */
799 while (j < t->size &&
800 table_to_bkey(t, j) <= k)
801 j++;
802
803 /*
804 * Adjust all the lookup table entries, and find a new key for any that
805 * have gotten too big
806 */
807 for (; j < t->size; j++) {
808 t->prev[j] += shift;
809
810 if (t->prev[j] > 7) {
811 k = table_to_bkey(t, j - 1);
812
813 while (k < cacheline_to_bkey(t, j, 0))
814 k = bkey_next(k);
815
816 t->prev[j] = bkey_to_cacheline_offset(t, j, k);
817 }
818 }
819
820 if (t->size == b->set->tree + btree_keys_cachelines(b) - t->tree)
821 return;
822
823 /* Possibly add a new entry to the end of the lookup table */
824
825 for (k = table_to_bkey(t, t->size - 1);
826 k != bset_bkey_last(t->data);
827 k = bkey_next(k))
828 if (t->size == bkey_to_cacheline(t, k)) {
829 t->prev[t->size] =
830 bkey_to_cacheline_offset(t, t->size, k);
831 t->size++;
832 }
833}
834
835/*
836 * Tries to merge l and r: l should be lower than r
837 * Returns true if we were able to merge. If we did merge, l will be the merged
838 * key, r will be untouched.
839 */
840bool bch_bkey_try_merge(struct btree_keys *b, struct bkey *l, struct bkey *r)
841{
842 if (!b->ops->key_merge)
843 return false;
844
845 /*
846 * Generic header checks
847 * Assumes left and right are in order
848 * Left and right must be exactly aligned
849 */
850 if (!bch_bkey_equal_header(l, r) ||
851 bkey_cmp(l, &START_KEY(r)))
852 return false;
853
854 return b->ops->key_merge(b, l, r);
855}
856
857void bch_bset_insert(struct btree_keys *b, struct bkey *where,
858 struct bkey *insert)
859{
860 struct bset_tree *t = bset_tree_last(b);
861
862 BUG_ON(!b->last_set_unwritten);
863 BUG_ON(bset_byte_offset(b, t->data) +
864 __set_bytes(t->data, t->data->keys + bkey_u64s(insert)) >
865 PAGE_SIZE << b->page_order);
866
867 memmove((uint64_t *) where + bkey_u64s(insert),
868 where,
869 (void *) bset_bkey_last(t->data) - (void *) where);
870
871 t->data->keys += bkey_u64s(insert);
872 bkey_copy(where, insert);
873 bch_bset_fix_lookup_table(b, t, where);
874}
875
876unsigned int bch_btree_insert_key(struct btree_keys *b, struct bkey *k,
877 struct bkey *replace_key)
878{
879 unsigned int status = BTREE_INSERT_STATUS_NO_INSERT;
880 struct bset *i = bset_tree_last(b)->data;
881 struct bkey *m, *prev = NULL;
882 struct btree_iter iter;
883 struct bkey preceding_key_on_stack = ZERO_KEY;
884 struct bkey *preceding_key_p = &preceding_key_on_stack;
885
886 BUG_ON(b->ops->is_extents && !KEY_SIZE(k));
887
888 /*
889 * If k has preceding key, preceding_key_p will be set to address
890 * of k's preceding key; otherwise preceding_key_p will be set
891 * to NULL inside preceding_key().
892 */
893 if (b->ops->is_extents)
894 preceding_key(&START_KEY(k), &preceding_key_p);
895 else
896 preceding_key(k, &preceding_key_p);
897
898 m = bch_btree_iter_init(b, &iter, preceding_key_p);
899
900 if (b->ops->insert_fixup(b, k, &iter, replace_key))
901 return status;
902
903 status = BTREE_INSERT_STATUS_INSERT;
904
905 while (m != bset_bkey_last(i) &&
906 bkey_cmp(k, b->ops->is_extents ? &START_KEY(m) : m) > 0) {
907 prev = m;
908 m = bkey_next(m);
909 }
910
911 /* prev is in the tree, if we merge we're done */
912 status = BTREE_INSERT_STATUS_BACK_MERGE;
913 if (prev &&
914 bch_bkey_try_merge(b, prev, k))
915 goto merged;
916#if 0
917 status = BTREE_INSERT_STATUS_OVERWROTE;
918 if (m != bset_bkey_last(i) &&
919 KEY_PTRS(m) == KEY_PTRS(k) && !KEY_SIZE(m))
920 goto copy;
921#endif
922 status = BTREE_INSERT_STATUS_FRONT_MERGE;
923 if (m != bset_bkey_last(i) &&
924 bch_bkey_try_merge(b, k, m))
925 goto copy;
926
927 bch_bset_insert(b, m, k);
928copy: bkey_copy(m, k);
929merged:
930 return status;
931}
932
933/* Lookup */
934
935struct bset_search_iter {
936 struct bkey *l, *r;
937};
938
939static struct bset_search_iter bset_search_write_set(struct bset_tree *t,
940 const struct bkey *search)
941{
942 unsigned int li = 0, ri = t->size;
943
944 while (li + 1 != ri) {
945 unsigned int m = (li + ri) >> 1;
946
947 if (bkey_cmp(table_to_bkey(t, m), search) > 0)
948 ri = m;
949 else
950 li = m;
951 }
952
953 return (struct bset_search_iter) {
954 table_to_bkey(t, li),
955 ri < t->size ? table_to_bkey(t, ri) : bset_bkey_last(t->data)
956 };
957}
958
959static struct bset_search_iter bset_search_tree(struct bset_tree *t,
960 const struct bkey *search)
961{
962 struct bkey *l, *r;
963 struct bkey_float *f;
964 unsigned int inorder, j, n = 1;
965
966 do {
967 unsigned int p = n << 4;
968
969 if (p < t->size)
970 prefetch(&t->tree[p]);
971
972 j = n;
973 f = &t->tree[j];
974
975 if (likely(f->exponent != 127)) {
976 if (f->mantissa >= bfloat_mantissa(search, f))
977 n = j * 2;
978 else
979 n = j * 2 + 1;
980 } else {
981 if (bkey_cmp(tree_to_bkey(t, j), search) > 0)
982 n = j * 2;
983 else
984 n = j * 2 + 1;
985 }
986 } while (n < t->size);
987
988 inorder = to_inorder(j, t);
989
990 /*
991 * n would have been the node we recursed to - the low bit tells us if
992 * we recursed left or recursed right.
993 */
994 if (n & 1) {
995 l = cacheline_to_bkey(t, inorder, f->m);
996
997 if (++inorder != t->size) {
998 f = &t->tree[inorder_next(j, t->size)];
999 r = cacheline_to_bkey(t, inorder, f->m);
1000 } else
1001 r = bset_bkey_last(t->data);
1002 } else {
1003 r = cacheline_to_bkey(t, inorder, f->m);
1004
1005 if (--inorder) {
1006 f = &t->tree[inorder_prev(j, t->size)];
1007 l = cacheline_to_bkey(t, inorder, f->m);
1008 } else
1009 l = t->data->start;
1010 }
1011
1012 return (struct bset_search_iter) {l, r};
1013}
1014
1015struct bkey *__bch_bset_search(struct btree_keys *b, struct bset_tree *t,
1016 const struct bkey *search)
1017{
1018 struct bset_search_iter i;
1019
1020 /*
1021 * First, we search for a cacheline, then lastly we do a linear search
1022 * within that cacheline.
1023 *
1024 * To search for the cacheline, there's three different possibilities:
1025 * * The set is too small to have a search tree, so we just do a linear
1026 * search over the whole set.
1027 * * The set is the one we're currently inserting into; keeping a full
1028 * auxiliary search tree up to date would be too expensive, so we
1029 * use a much simpler lookup table to do a binary search -
1030 * bset_search_write_set().
1031 * * Or we use the auxiliary search tree we constructed earlier -
1032 * bset_search_tree()
1033 */
1034
1035 if (unlikely(!t->size)) {
1036 i.l = t->data->start;
1037 i.r = bset_bkey_last(t->data);
1038 } else if (bset_written(b, t)) {
1039 /*
1040 * Each node in the auxiliary search tree covers a certain range
1041 * of bits, and keys above and below the set it covers might
1042 * differ outside those bits - so we have to special case the
1043 * start and end - handle that here:
1044 */
1045
1046 if (unlikely(bkey_cmp(search, &t->end) >= 0))
1047 return bset_bkey_last(t->data);
1048
1049 if (unlikely(bkey_cmp(search, t->data->start) < 0))
1050 return t->data->start;
1051
1052 i = bset_search_tree(t, search);
1053 } else {
1054 BUG_ON(!b->nsets &&
1055 t->size < bkey_to_cacheline(t, bset_bkey_last(t->data)));
1056
1057 i = bset_search_write_set(t, search);
1058 }
1059
1060 if (btree_keys_expensive_checks(b)) {
1061 BUG_ON(bset_written(b, t) &&
1062 i.l != t->data->start &&
1063 bkey_cmp(tree_to_prev_bkey(t,
1064 inorder_to_tree(bkey_to_cacheline(t, i.l), t)),
1065 search) > 0);
1066
1067 BUG_ON(i.r != bset_bkey_last(t->data) &&
1068 bkey_cmp(i.r, search) <= 0);
1069 }
1070
1071 while (likely(i.l != i.r) &&
1072 bkey_cmp(i.l, search) <= 0)
1073 i.l = bkey_next(i.l);
1074
1075 return i.l;
1076}
1077
1078/* Btree iterator */
1079
1080typedef bool (btree_iter_cmp_fn)(struct btree_iter_set,
1081 struct btree_iter_set);
1082
1083static inline bool btree_iter_cmp(struct btree_iter_set l,
1084 struct btree_iter_set r)
1085{
1086 return bkey_cmp(l.k, r.k) > 0;
1087}
1088
1089static inline bool btree_iter_end(struct btree_iter *iter)
1090{
1091 return !iter->used;
1092}
1093
1094void bch_btree_iter_push(struct btree_iter *iter, struct bkey *k,
1095 struct bkey *end)
1096{
1097 if (k != end)
1098 BUG_ON(!heap_add(iter,
1099 ((struct btree_iter_set) { k, end }),
1100 btree_iter_cmp));
1101}
1102
1103static struct bkey *__bch_btree_iter_init(struct btree_keys *b,
1104 struct btree_iter *iter,
1105 struct bkey *search,
1106 struct bset_tree *start)
1107{
1108 struct bkey *ret = NULL;
1109
1110 iter->size = ARRAY_SIZE(iter->data);
1111 iter->used = 0;
1112
1113#ifdef CONFIG_BCACHE_DEBUG
1114 iter->b = b;
1115#endif
1116
1117 for (; start <= bset_tree_last(b); start++) {
1118 ret = bch_bset_search(b, start, search);
1119 bch_btree_iter_push(iter, ret, bset_bkey_last(start->data));
1120 }
1121
1122 return ret;
1123}
1124
1125struct bkey *bch_btree_iter_init(struct btree_keys *b,
1126 struct btree_iter *iter,
1127 struct bkey *search)
1128{
1129 return __bch_btree_iter_init(b, iter, search, b->set);
1130}
1131
1132static inline struct bkey *__bch_btree_iter_next(struct btree_iter *iter,
1133 btree_iter_cmp_fn *cmp)
1134{
1135 struct btree_iter_set b __maybe_unused;
1136 struct bkey *ret = NULL;
1137
1138 if (!btree_iter_end(iter)) {
1139 bch_btree_iter_next_check(iter);
1140
1141 ret = iter->data->k;
1142 iter->data->k = bkey_next(iter->data->k);
1143
1144 if (iter->data->k > iter->data->end) {
1145 WARN_ONCE(1, "bset was corrupt!\n");
1146 iter->data->k = iter->data->end;
1147 }
1148
1149 if (iter->data->k == iter->data->end)
1150 heap_pop(iter, b, cmp);
1151 else
1152 heap_sift(iter, 0, cmp);
1153 }
1154
1155 return ret;
1156}
1157
1158struct bkey *bch_btree_iter_next(struct btree_iter *iter)
1159{
1160 return __bch_btree_iter_next(iter, btree_iter_cmp);
1161
1162}
1163
1164struct bkey *bch_btree_iter_next_filter(struct btree_iter *iter,
1165 struct btree_keys *b, ptr_filter_fn fn)
1166{
1167 struct bkey *ret;
1168
1169 do {
1170 ret = bch_btree_iter_next(iter);
1171 } while (ret && fn(b, ret));
1172
1173 return ret;
1174}
1175
1176/* Mergesort */
1177
1178void bch_bset_sort_state_free(struct bset_sort_state *state)
1179{
1180 mempool_exit(&state->pool);
1181}
1182
1183int bch_bset_sort_state_init(struct bset_sort_state *state,
1184 unsigned int page_order)
1185{
1186 spin_lock_init(&state->time.lock);
1187
1188 state->page_order = page_order;
1189 state->crit_factor = int_sqrt(1 << page_order);
1190
1191 return mempool_init_page_pool(&state->pool, 1, page_order);
1192}
1193
1194static void btree_mergesort(struct btree_keys *b, struct bset *out,
1195 struct btree_iter *iter,
1196 bool fixup, bool remove_stale)
1197{
1198 int i;
1199 struct bkey *k, *last = NULL;
1200 BKEY_PADDED(k) tmp;
1201 bool (*bad)(struct btree_keys *, const struct bkey *) = remove_stale
1202 ? bch_ptr_bad
1203 : bch_ptr_invalid;
1204
1205 /* Heapify the iterator, using our comparison function */
1206 for (i = iter->used / 2 - 1; i >= 0; --i)
1207 heap_sift(iter, i, b->ops->sort_cmp);
1208
1209 while (!btree_iter_end(iter)) {
1210 if (b->ops->sort_fixup && fixup)
1211 k = b->ops->sort_fixup(iter, &tmp.k);
1212 else
1213 k = NULL;
1214
1215 if (!k)
1216 k = __bch_btree_iter_next(iter, b->ops->sort_cmp);
1217
1218 if (bad(b, k))
1219 continue;
1220
1221 if (!last) {
1222 last = out->start;
1223 bkey_copy(last, k);
1224 } else if (!bch_bkey_try_merge(b, last, k)) {
1225 last = bkey_next(last);
1226 bkey_copy(last, k);
1227 }
1228 }
1229
1230 out->keys = last ? (uint64_t *) bkey_next(last) - out->d : 0;
1231
1232 pr_debug("sorted %i keys\n", out->keys);
1233}
1234
1235static void __btree_sort(struct btree_keys *b, struct btree_iter *iter,
1236 unsigned int start, unsigned int order, bool fixup,
1237 struct bset_sort_state *state)
1238{
1239 uint64_t start_time;
1240 bool used_mempool = false;
1241 struct bset *out = (void *) __get_free_pages(__GFP_NOWARN|GFP_NOWAIT,
1242 order);
1243 if (!out) {
1244 struct page *outp;
1245
1246 BUG_ON(order > state->page_order);
1247
1248 outp = mempool_alloc(&state->pool, GFP_NOIO);
1249 out = page_address(outp);
1250 used_mempool = true;
1251 order = state->page_order;
1252 }
1253
1254 start_time = local_clock();
1255
1256 btree_mergesort(b, out, iter, fixup, false);
1257 b->nsets = start;
1258
1259 if (!start && order == b->page_order) {
1260 /*
1261 * Our temporary buffer is the same size as the btree node's
1262 * buffer, we can just swap buffers instead of doing a big
1263 * memcpy()
1264 *
1265 * Don't worry event 'out' is allocated from mempool, it can
1266 * still be swapped here. Because state->pool is a page mempool
1267 * created by mempool_init_page_pool(), which allocates
1268 * pages by alloc_pages() indeed.
1269 */
1270
1271 out->magic = b->set->data->magic;
1272 out->seq = b->set->data->seq;
1273 out->version = b->set->data->version;
1274 swap(out, b->set->data);
1275 } else {
1276 b->set[start].data->keys = out->keys;
1277 memcpy(b->set[start].data->start, out->start,
1278 (void *) bset_bkey_last(out) - (void *) out->start);
1279 }
1280
1281 if (used_mempool)
1282 mempool_free(virt_to_page(out), &state->pool);
1283 else
1284 free_pages((unsigned long) out, order);
1285
1286 bch_bset_build_written_tree(b);
1287
1288 if (!start)
1289 bch_time_stats_update(&state->time, start_time);
1290}
1291
1292void bch_btree_sort_partial(struct btree_keys *b, unsigned int start,
1293 struct bset_sort_state *state)
1294{
1295 size_t order = b->page_order, keys = 0;
1296 struct btree_iter iter;
1297 int oldsize = bch_count_data(b);
1298
1299 __bch_btree_iter_init(b, &iter, NULL, &b->set[start]);
1300
1301 if (start) {
1302 unsigned int i;
1303
1304 for (i = start; i <= b->nsets; i++)
1305 keys += b->set[i].data->keys;
1306
1307 order = get_order(__set_bytes(b->set->data, keys));
1308 }
1309
1310 __btree_sort(b, &iter, start, order, false, state);
1311
1312 EBUG_ON(oldsize >= 0 && bch_count_data(b) != oldsize);
1313}
1314
1315void bch_btree_sort_and_fix_extents(struct btree_keys *b,
1316 struct btree_iter *iter,
1317 struct bset_sort_state *state)
1318{
1319 __btree_sort(b, iter, 0, b->page_order, true, state);
1320}
1321
1322void bch_btree_sort_into(struct btree_keys *b, struct btree_keys *new,
1323 struct bset_sort_state *state)
1324{
1325 uint64_t start_time = local_clock();
1326 struct btree_iter iter;
1327
1328 bch_btree_iter_init(b, &iter, NULL);
1329
1330 btree_mergesort(b, new->set->data, &iter, false, true);
1331
1332 bch_time_stats_update(&state->time, start_time);
1333
1334 new->set->size = 0; // XXX: why?
1335}
1336
1337#define SORT_CRIT (4096 / sizeof(uint64_t))
1338
1339void bch_btree_sort_lazy(struct btree_keys *b, struct bset_sort_state *state)
1340{
1341 unsigned int crit = SORT_CRIT;
1342 int i;
1343
1344 /* Don't sort if nothing to do */
1345 if (!b->nsets)
1346 goto out;
1347
1348 for (i = b->nsets - 1; i >= 0; --i) {
1349 crit *= state->crit_factor;
1350
1351 if (b->set[i].data->keys < crit) {
1352 bch_btree_sort_partial(b, i, state);
1353 return;
1354 }
1355 }
1356
1357 /* Sort if we'd overflow */
1358 if (b->nsets + 1 == MAX_BSETS) {
1359 bch_btree_sort(b, state);
1360 return;
1361 }
1362
1363out:
1364 bch_bset_build_written_tree(b);
1365}
1366
1367void bch_btree_keys_stats(struct btree_keys *b, struct bset_stats *stats)
1368{
1369 unsigned int i;
1370
1371 for (i = 0; i <= b->nsets; i++) {
1372 struct bset_tree *t = &b->set[i];
1373 size_t bytes = t->data->keys * sizeof(uint64_t);
1374 size_t j;
1375
1376 if (bset_written(b, t)) {
1377 stats->sets_written++;
1378 stats->bytes_written += bytes;
1379
1380 stats->floats += t->size - 1;
1381
1382 for (j = 1; j < t->size; j++)
1383 if (t->tree[j].exponent == 127)
1384 stats->failed++;
1385 } else {
1386 stats->sets_unwritten++;
1387 stats->bytes_unwritten += bytes;
1388 }
1389 }
1390}
1/*
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#define pr_fmt(fmt) "bcache: %s() " fmt "\n", __func__
9
10#include "util.h"
11#include "bset.h"
12
13#include <linux/console.h>
14#include <linux/random.h>
15#include <linux/prefetch.h>
16
17#ifdef CONFIG_BCACHE_DEBUG
18
19void bch_dump_bset(struct btree_keys *b, struct bset *i, unsigned set)
20{
21 struct bkey *k, *next;
22
23 for (k = i->start; k < bset_bkey_last(i); k = next) {
24 next = bkey_next(k);
25
26 printk(KERN_ERR "block %u key %u/%u: ", set,
27 (unsigned) ((u64 *) k - i->d), i->keys);
28
29 if (b->ops->key_dump)
30 b->ops->key_dump(b, k);
31 else
32 printk("%llu:%llu\n", KEY_INODE(k), KEY_OFFSET(k));
33
34 if (next < bset_bkey_last(i) &&
35 bkey_cmp(k, b->ops->is_extents ?
36 &START_KEY(next) : next) > 0)
37 printk(KERN_ERR "Key skipped backwards\n");
38 }
39}
40
41void bch_dump_bucket(struct btree_keys *b)
42{
43 unsigned i;
44
45 console_lock();
46 for (i = 0; i <= b->nsets; i++)
47 bch_dump_bset(b, b->set[i].data,
48 bset_sector_offset(b, b->set[i].data));
49 console_unlock();
50}
51
52int __bch_count_data(struct btree_keys *b)
53{
54 unsigned ret = 0;
55 struct btree_iter iter;
56 struct bkey *k;
57
58 if (b->ops->is_extents)
59 for_each_key(b, k, &iter)
60 ret += KEY_SIZE(k);
61 return ret;
62}
63
64void __bch_check_keys(struct btree_keys *b, const char *fmt, ...)
65{
66 va_list args;
67 struct bkey *k, *p = NULL;
68 struct btree_iter iter;
69 const char *err;
70
71 for_each_key(b, k, &iter) {
72 if (b->ops->is_extents) {
73 err = "Keys out of order";
74 if (p && bkey_cmp(&START_KEY(p), &START_KEY(k)) > 0)
75 goto bug;
76
77 if (bch_ptr_invalid(b, k))
78 continue;
79
80 err = "Overlapping keys";
81 if (p && bkey_cmp(p, &START_KEY(k)) > 0)
82 goto bug;
83 } else {
84 if (bch_ptr_bad(b, k))
85 continue;
86
87 err = "Duplicate keys";
88 if (p && !bkey_cmp(p, k))
89 goto bug;
90 }
91 p = k;
92 }
93#if 0
94 err = "Key larger than btree node key";
95 if (p && bkey_cmp(p, &b->key) > 0)
96 goto bug;
97#endif
98 return;
99bug:
100 bch_dump_bucket(b);
101
102 va_start(args, fmt);
103 vprintk(fmt, args);
104 va_end(args);
105
106 panic("bch_check_keys error: %s:\n", err);
107}
108
109static void bch_btree_iter_next_check(struct btree_iter *iter)
110{
111 struct bkey *k = iter->data->k, *next = bkey_next(k);
112
113 if (next < iter->data->end &&
114 bkey_cmp(k, iter->b->ops->is_extents ?
115 &START_KEY(next) : next) > 0) {
116 bch_dump_bucket(iter->b);
117 panic("Key skipped backwards\n");
118 }
119}
120
121#else
122
123static inline void bch_btree_iter_next_check(struct btree_iter *iter) {}
124
125#endif
126
127/* Keylists */
128
129int __bch_keylist_realloc(struct keylist *l, unsigned u64s)
130{
131 size_t oldsize = bch_keylist_nkeys(l);
132 size_t newsize = oldsize + u64s;
133 uint64_t *old_keys = l->keys_p == l->inline_keys ? NULL : l->keys_p;
134 uint64_t *new_keys;
135
136 newsize = roundup_pow_of_two(newsize);
137
138 if (newsize <= KEYLIST_INLINE ||
139 roundup_pow_of_two(oldsize) == newsize)
140 return 0;
141
142 new_keys = krealloc(old_keys, sizeof(uint64_t) * newsize, GFP_NOIO);
143
144 if (!new_keys)
145 return -ENOMEM;
146
147 if (!old_keys)
148 memcpy(new_keys, l->inline_keys, sizeof(uint64_t) * oldsize);
149
150 l->keys_p = new_keys;
151 l->top_p = new_keys + oldsize;
152
153 return 0;
154}
155
156struct bkey *bch_keylist_pop(struct keylist *l)
157{
158 struct bkey *k = l->keys;
159
160 if (k == l->top)
161 return NULL;
162
163 while (bkey_next(k) != l->top)
164 k = bkey_next(k);
165
166 return l->top = k;
167}
168
169void bch_keylist_pop_front(struct keylist *l)
170{
171 l->top_p -= bkey_u64s(l->keys);
172
173 memmove(l->keys,
174 bkey_next(l->keys),
175 bch_keylist_bytes(l));
176}
177
178/* Key/pointer manipulation */
179
180void bch_bkey_copy_single_ptr(struct bkey *dest, const struct bkey *src,
181 unsigned i)
182{
183 BUG_ON(i > KEY_PTRS(src));
184
185 /* Only copy the header, key, and one pointer. */
186 memcpy(dest, src, 2 * sizeof(uint64_t));
187 dest->ptr[0] = src->ptr[i];
188 SET_KEY_PTRS(dest, 1);
189 /* We didn't copy the checksum so clear that bit. */
190 SET_KEY_CSUM(dest, 0);
191}
192
193bool __bch_cut_front(const struct bkey *where, struct bkey *k)
194{
195 unsigned i, len = 0;
196
197 if (bkey_cmp(where, &START_KEY(k)) <= 0)
198 return false;
199
200 if (bkey_cmp(where, k) < 0)
201 len = KEY_OFFSET(k) - KEY_OFFSET(where);
202 else
203 bkey_copy_key(k, where);
204
205 for (i = 0; i < KEY_PTRS(k); i++)
206 SET_PTR_OFFSET(k, i, PTR_OFFSET(k, i) + KEY_SIZE(k) - len);
207
208 BUG_ON(len > KEY_SIZE(k));
209 SET_KEY_SIZE(k, len);
210 return true;
211}
212
213bool __bch_cut_back(const struct bkey *where, struct bkey *k)
214{
215 unsigned len = 0;
216
217 if (bkey_cmp(where, k) >= 0)
218 return false;
219
220 BUG_ON(KEY_INODE(where) != KEY_INODE(k));
221
222 if (bkey_cmp(where, &START_KEY(k)) > 0)
223 len = KEY_OFFSET(where) - KEY_START(k);
224
225 bkey_copy_key(k, where);
226
227 BUG_ON(len > KEY_SIZE(k));
228 SET_KEY_SIZE(k, len);
229 return true;
230}
231
232/* Auxiliary search trees */
233
234/* 32 bits total: */
235#define BKEY_MID_BITS 3
236#define BKEY_EXPONENT_BITS 7
237#define BKEY_MANTISSA_BITS (32 - BKEY_MID_BITS - BKEY_EXPONENT_BITS)
238#define BKEY_MANTISSA_MASK ((1 << BKEY_MANTISSA_BITS) - 1)
239
240struct bkey_float {
241 unsigned exponent:BKEY_EXPONENT_BITS;
242 unsigned m:BKEY_MID_BITS;
243 unsigned mantissa:BKEY_MANTISSA_BITS;
244} __packed;
245
246/*
247 * BSET_CACHELINE was originally intended to match the hardware cacheline size -
248 * it used to be 64, but I realized the lookup code would touch slightly less
249 * memory if it was 128.
250 *
251 * It definites the number of bytes (in struct bset) per struct bkey_float in
252 * the auxiliar search tree - when we're done searching the bset_float tree we
253 * have this many bytes left that we do a linear search over.
254 *
255 * Since (after level 5) every level of the bset_tree is on a new cacheline,
256 * we're touching one fewer cacheline in the bset tree in exchange for one more
257 * cacheline in the linear search - but the linear search might stop before it
258 * gets to the second cacheline.
259 */
260
261#define BSET_CACHELINE 128
262
263/* Space required for the btree node keys */
264static inline size_t btree_keys_bytes(struct btree_keys *b)
265{
266 return PAGE_SIZE << b->page_order;
267}
268
269static inline size_t btree_keys_cachelines(struct btree_keys *b)
270{
271 return btree_keys_bytes(b) / BSET_CACHELINE;
272}
273
274/* Space required for the auxiliary search trees */
275static inline size_t bset_tree_bytes(struct btree_keys *b)
276{
277 return btree_keys_cachelines(b) * sizeof(struct bkey_float);
278}
279
280/* Space required for the prev pointers */
281static inline size_t bset_prev_bytes(struct btree_keys *b)
282{
283 return btree_keys_cachelines(b) * sizeof(uint8_t);
284}
285
286/* Memory allocation */
287
288void bch_btree_keys_free(struct btree_keys *b)
289{
290 struct bset_tree *t = b->set;
291
292 if (bset_prev_bytes(b) < PAGE_SIZE)
293 kfree(t->prev);
294 else
295 free_pages((unsigned long) t->prev,
296 get_order(bset_prev_bytes(b)));
297
298 if (bset_tree_bytes(b) < PAGE_SIZE)
299 kfree(t->tree);
300 else
301 free_pages((unsigned long) t->tree,
302 get_order(bset_tree_bytes(b)));
303
304 free_pages((unsigned long) t->data, b->page_order);
305
306 t->prev = NULL;
307 t->tree = NULL;
308 t->data = NULL;
309}
310EXPORT_SYMBOL(bch_btree_keys_free);
311
312int bch_btree_keys_alloc(struct btree_keys *b, unsigned page_order, gfp_t gfp)
313{
314 struct bset_tree *t = b->set;
315
316 BUG_ON(t->data);
317
318 b->page_order = page_order;
319
320 t->data = (void *) __get_free_pages(gfp, b->page_order);
321 if (!t->data)
322 goto err;
323
324 t->tree = bset_tree_bytes(b) < PAGE_SIZE
325 ? kmalloc(bset_tree_bytes(b), gfp)
326 : (void *) __get_free_pages(gfp, get_order(bset_tree_bytes(b)));
327 if (!t->tree)
328 goto err;
329
330 t->prev = bset_prev_bytes(b) < PAGE_SIZE
331 ? kmalloc(bset_prev_bytes(b), gfp)
332 : (void *) __get_free_pages(gfp, get_order(bset_prev_bytes(b)));
333 if (!t->prev)
334 goto err;
335
336 return 0;
337err:
338 bch_btree_keys_free(b);
339 return -ENOMEM;
340}
341EXPORT_SYMBOL(bch_btree_keys_alloc);
342
343void bch_btree_keys_init(struct btree_keys *b, const struct btree_keys_ops *ops,
344 bool *expensive_debug_checks)
345{
346 unsigned i;
347
348 b->ops = ops;
349 b->expensive_debug_checks = expensive_debug_checks;
350 b->nsets = 0;
351 b->last_set_unwritten = 0;
352
353 /* XXX: shouldn't be needed */
354 for (i = 0; i < MAX_BSETS; i++)
355 b->set[i].size = 0;
356 /*
357 * Second loop starts at 1 because b->keys[0]->data is the memory we
358 * allocated
359 */
360 for (i = 1; i < MAX_BSETS; i++)
361 b->set[i].data = NULL;
362}
363EXPORT_SYMBOL(bch_btree_keys_init);
364
365/* Binary tree stuff for auxiliary search trees */
366
367static unsigned inorder_next(unsigned j, unsigned size)
368{
369 if (j * 2 + 1 < size) {
370 j = j * 2 + 1;
371
372 while (j * 2 < size)
373 j *= 2;
374 } else
375 j >>= ffz(j) + 1;
376
377 return j;
378}
379
380static unsigned inorder_prev(unsigned j, unsigned size)
381{
382 if (j * 2 < size) {
383 j = j * 2;
384
385 while (j * 2 + 1 < size)
386 j = j * 2 + 1;
387 } else
388 j >>= ffs(j);
389
390 return j;
391}
392
393/* I have no idea why this code works... and I'm the one who wrote it
394 *
395 * However, I do know what it does:
396 * Given a binary tree constructed in an array (i.e. how you normally implement
397 * a heap), it converts a node in the tree - referenced by array index - to the
398 * index it would have if you did an inorder traversal.
399 *
400 * Also tested for every j, size up to size somewhere around 6 million.
401 *
402 * The binary tree starts at array index 1, not 0
403 * extra is a function of size:
404 * extra = (size - rounddown_pow_of_two(size - 1)) << 1;
405 */
406static unsigned __to_inorder(unsigned j, unsigned size, unsigned extra)
407{
408 unsigned b = fls(j);
409 unsigned shift = fls(size - 1) - b;
410
411 j ^= 1U << (b - 1);
412 j <<= 1;
413 j |= 1;
414 j <<= shift;
415
416 if (j > extra)
417 j -= (j - extra) >> 1;
418
419 return j;
420}
421
422static unsigned to_inorder(unsigned j, struct bset_tree *t)
423{
424 return __to_inorder(j, t->size, t->extra);
425}
426
427static unsigned __inorder_to_tree(unsigned j, unsigned size, unsigned extra)
428{
429 unsigned shift;
430
431 if (j > extra)
432 j += j - extra;
433
434 shift = ffs(j);
435
436 j >>= shift;
437 j |= roundup_pow_of_two(size) >> shift;
438
439 return j;
440}
441
442static unsigned inorder_to_tree(unsigned j, struct bset_tree *t)
443{
444 return __inorder_to_tree(j, t->size, t->extra);
445}
446
447#if 0
448void inorder_test(void)
449{
450 unsigned long done = 0;
451 ktime_t start = ktime_get();
452
453 for (unsigned size = 2;
454 size < 65536000;
455 size++) {
456 unsigned extra = (size - rounddown_pow_of_two(size - 1)) << 1;
457 unsigned i = 1, j = rounddown_pow_of_two(size - 1);
458
459 if (!(size % 4096))
460 printk(KERN_NOTICE "loop %u, %llu per us\n", size,
461 done / ktime_us_delta(ktime_get(), start));
462
463 while (1) {
464 if (__inorder_to_tree(i, size, extra) != j)
465 panic("size %10u j %10u i %10u", size, j, i);
466
467 if (__to_inorder(j, size, extra) != i)
468 panic("size %10u j %10u i %10u", size, j, i);
469
470 if (j == rounddown_pow_of_two(size) - 1)
471 break;
472
473 BUG_ON(inorder_prev(inorder_next(j, size), size) != j);
474
475 j = inorder_next(j, size);
476 i++;
477 }
478
479 done += size - 1;
480 }
481}
482#endif
483
484/*
485 * Cacheline/offset <-> bkey pointer arithmetic:
486 *
487 * t->tree is a binary search tree in an array; each node corresponds to a key
488 * in one cacheline in t->set (BSET_CACHELINE bytes).
489 *
490 * This means we don't have to store the full index of the key that a node in
491 * the binary tree points to; to_inorder() gives us the cacheline, and then
492 * bkey_float->m gives us the offset within that cacheline, in units of 8 bytes.
493 *
494 * cacheline_to_bkey() and friends abstract out all the pointer arithmetic to
495 * make this work.
496 *
497 * To construct the bfloat for an arbitrary key we need to know what the key
498 * immediately preceding it is: we have to check if the two keys differ in the
499 * bits we're going to store in bkey_float->mantissa. t->prev[j] stores the size
500 * of the previous key so we can walk backwards to it from t->tree[j]'s key.
501 */
502
503static struct bkey *cacheline_to_bkey(struct bset_tree *t, unsigned cacheline,
504 unsigned offset)
505{
506 return ((void *) t->data) + cacheline * BSET_CACHELINE + offset * 8;
507}
508
509static unsigned bkey_to_cacheline(struct bset_tree *t, struct bkey *k)
510{
511 return ((void *) k - (void *) t->data) / BSET_CACHELINE;
512}
513
514static unsigned bkey_to_cacheline_offset(struct bset_tree *t,
515 unsigned cacheline,
516 struct bkey *k)
517{
518 return (u64 *) k - (u64 *) cacheline_to_bkey(t, cacheline, 0);
519}
520
521static struct bkey *tree_to_bkey(struct bset_tree *t, unsigned j)
522{
523 return cacheline_to_bkey(t, to_inorder(j, t), t->tree[j].m);
524}
525
526static struct bkey *tree_to_prev_bkey(struct bset_tree *t, unsigned j)
527{
528 return (void *) (((uint64_t *) tree_to_bkey(t, j)) - t->prev[j]);
529}
530
531/*
532 * For the write set - the one we're currently inserting keys into - we don't
533 * maintain a full search tree, we just keep a simple lookup table in t->prev.
534 */
535static struct bkey *table_to_bkey(struct bset_tree *t, unsigned cacheline)
536{
537 return cacheline_to_bkey(t, cacheline, t->prev[cacheline]);
538}
539
540static inline uint64_t shrd128(uint64_t high, uint64_t low, uint8_t shift)
541{
542 low >>= shift;
543 low |= (high << 1) << (63U - shift);
544 return low;
545}
546
547static inline unsigned bfloat_mantissa(const struct bkey *k,
548 struct bkey_float *f)
549{
550 const uint64_t *p = &k->low - (f->exponent >> 6);
551 return shrd128(p[-1], p[0], f->exponent & 63) & BKEY_MANTISSA_MASK;
552}
553
554static void make_bfloat(struct bset_tree *t, unsigned j)
555{
556 struct bkey_float *f = &t->tree[j];
557 struct bkey *m = tree_to_bkey(t, j);
558 struct bkey *p = tree_to_prev_bkey(t, j);
559
560 struct bkey *l = is_power_of_2(j)
561 ? t->data->start
562 : tree_to_prev_bkey(t, j >> ffs(j));
563
564 struct bkey *r = is_power_of_2(j + 1)
565 ? bset_bkey_idx(t->data, t->data->keys - bkey_u64s(&t->end))
566 : tree_to_bkey(t, j >> (ffz(j) + 1));
567
568 BUG_ON(m < l || m > r);
569 BUG_ON(bkey_next(p) != m);
570
571 if (KEY_INODE(l) != KEY_INODE(r))
572 f->exponent = fls64(KEY_INODE(r) ^ KEY_INODE(l)) + 64;
573 else
574 f->exponent = fls64(r->low ^ l->low);
575
576 f->exponent = max_t(int, f->exponent - BKEY_MANTISSA_BITS, 0);
577
578 /*
579 * Setting f->exponent = 127 flags this node as failed, and causes the
580 * lookup code to fall back to comparing against the original key.
581 */
582
583 if (bfloat_mantissa(m, f) != bfloat_mantissa(p, f))
584 f->mantissa = bfloat_mantissa(m, f) - 1;
585 else
586 f->exponent = 127;
587}
588
589static void bset_alloc_tree(struct btree_keys *b, struct bset_tree *t)
590{
591 if (t != b->set) {
592 unsigned j = roundup(t[-1].size,
593 64 / sizeof(struct bkey_float));
594
595 t->tree = t[-1].tree + j;
596 t->prev = t[-1].prev + j;
597 }
598
599 while (t < b->set + MAX_BSETS)
600 t++->size = 0;
601}
602
603static void bch_bset_build_unwritten_tree(struct btree_keys *b)
604{
605 struct bset_tree *t = bset_tree_last(b);
606
607 BUG_ON(b->last_set_unwritten);
608 b->last_set_unwritten = 1;
609
610 bset_alloc_tree(b, t);
611
612 if (t->tree != b->set->tree + btree_keys_cachelines(b)) {
613 t->prev[0] = bkey_to_cacheline_offset(t, 0, t->data->start);
614 t->size = 1;
615 }
616}
617
618void bch_bset_init_next(struct btree_keys *b, struct bset *i, uint64_t magic)
619{
620 if (i != b->set->data) {
621 b->set[++b->nsets].data = i;
622 i->seq = b->set->data->seq;
623 } else
624 get_random_bytes(&i->seq, sizeof(uint64_t));
625
626 i->magic = magic;
627 i->version = 0;
628 i->keys = 0;
629
630 bch_bset_build_unwritten_tree(b);
631}
632EXPORT_SYMBOL(bch_bset_init_next);
633
634void bch_bset_build_written_tree(struct btree_keys *b)
635{
636 struct bset_tree *t = bset_tree_last(b);
637 struct bkey *prev = NULL, *k = t->data->start;
638 unsigned j, cacheline = 1;
639
640 b->last_set_unwritten = 0;
641
642 bset_alloc_tree(b, t);
643
644 t->size = min_t(unsigned,
645 bkey_to_cacheline(t, bset_bkey_last(t->data)),
646 b->set->tree + btree_keys_cachelines(b) - t->tree);
647
648 if (t->size < 2) {
649 t->size = 0;
650 return;
651 }
652
653 t->extra = (t->size - rounddown_pow_of_two(t->size - 1)) << 1;
654
655 /* First we figure out where the first key in each cacheline is */
656 for (j = inorder_next(0, t->size);
657 j;
658 j = inorder_next(j, t->size)) {
659 while (bkey_to_cacheline(t, k) < cacheline)
660 prev = k, k = bkey_next(k);
661
662 t->prev[j] = bkey_u64s(prev);
663 t->tree[j].m = bkey_to_cacheline_offset(t, cacheline++, k);
664 }
665
666 while (bkey_next(k) != bset_bkey_last(t->data))
667 k = bkey_next(k);
668
669 t->end = *k;
670
671 /* Then we build the tree */
672 for (j = inorder_next(0, t->size);
673 j;
674 j = inorder_next(j, t->size))
675 make_bfloat(t, j);
676}
677EXPORT_SYMBOL(bch_bset_build_written_tree);
678
679/* Insert */
680
681void bch_bset_fix_invalidated_key(struct btree_keys *b, struct bkey *k)
682{
683 struct bset_tree *t;
684 unsigned inorder, j = 1;
685
686 for (t = b->set; t <= bset_tree_last(b); t++)
687 if (k < bset_bkey_last(t->data))
688 goto found_set;
689
690 BUG();
691found_set:
692 if (!t->size || !bset_written(b, t))
693 return;
694
695 inorder = bkey_to_cacheline(t, k);
696
697 if (k == t->data->start)
698 goto fix_left;
699
700 if (bkey_next(k) == bset_bkey_last(t->data)) {
701 t->end = *k;
702 goto fix_right;
703 }
704
705 j = inorder_to_tree(inorder, t);
706
707 if (j &&
708 j < t->size &&
709 k == tree_to_bkey(t, j))
710fix_left: do {
711 make_bfloat(t, j);
712 j = j * 2;
713 } while (j < t->size);
714
715 j = inorder_to_tree(inorder + 1, t);
716
717 if (j &&
718 j < t->size &&
719 k == tree_to_prev_bkey(t, j))
720fix_right: do {
721 make_bfloat(t, j);
722 j = j * 2 + 1;
723 } while (j < t->size);
724}
725EXPORT_SYMBOL(bch_bset_fix_invalidated_key);
726
727static void bch_bset_fix_lookup_table(struct btree_keys *b,
728 struct bset_tree *t,
729 struct bkey *k)
730{
731 unsigned shift = bkey_u64s(k);
732 unsigned j = bkey_to_cacheline(t, k);
733
734 /* We're getting called from btree_split() or btree_gc, just bail out */
735 if (!t->size)
736 return;
737
738 /* k is the key we just inserted; we need to find the entry in the
739 * lookup table for the first key that is strictly greater than k:
740 * it's either k's cacheline or the next one
741 */
742 while (j < t->size &&
743 table_to_bkey(t, j) <= k)
744 j++;
745
746 /* Adjust all the lookup table entries, and find a new key for any that
747 * have gotten too big
748 */
749 for (; j < t->size; j++) {
750 t->prev[j] += shift;
751
752 if (t->prev[j] > 7) {
753 k = table_to_bkey(t, j - 1);
754
755 while (k < cacheline_to_bkey(t, j, 0))
756 k = bkey_next(k);
757
758 t->prev[j] = bkey_to_cacheline_offset(t, j, k);
759 }
760 }
761
762 if (t->size == b->set->tree + btree_keys_cachelines(b) - t->tree)
763 return;
764
765 /* Possibly add a new entry to the end of the lookup table */
766
767 for (k = table_to_bkey(t, t->size - 1);
768 k != bset_bkey_last(t->data);
769 k = bkey_next(k))
770 if (t->size == bkey_to_cacheline(t, k)) {
771 t->prev[t->size] = bkey_to_cacheline_offset(t, t->size, k);
772 t->size++;
773 }
774}
775
776/*
777 * Tries to merge l and r: l should be lower than r
778 * Returns true if we were able to merge. If we did merge, l will be the merged
779 * key, r will be untouched.
780 */
781bool bch_bkey_try_merge(struct btree_keys *b, struct bkey *l, struct bkey *r)
782{
783 if (!b->ops->key_merge)
784 return false;
785
786 /*
787 * Generic header checks
788 * Assumes left and right are in order
789 * Left and right must be exactly aligned
790 */
791 if (!bch_bkey_equal_header(l, r) ||
792 bkey_cmp(l, &START_KEY(r)))
793 return false;
794
795 return b->ops->key_merge(b, l, r);
796}
797EXPORT_SYMBOL(bch_bkey_try_merge);
798
799void bch_bset_insert(struct btree_keys *b, struct bkey *where,
800 struct bkey *insert)
801{
802 struct bset_tree *t = bset_tree_last(b);
803
804 BUG_ON(!b->last_set_unwritten);
805 BUG_ON(bset_byte_offset(b, t->data) +
806 __set_bytes(t->data, t->data->keys + bkey_u64s(insert)) >
807 PAGE_SIZE << b->page_order);
808
809 memmove((uint64_t *) where + bkey_u64s(insert),
810 where,
811 (void *) bset_bkey_last(t->data) - (void *) where);
812
813 t->data->keys += bkey_u64s(insert);
814 bkey_copy(where, insert);
815 bch_bset_fix_lookup_table(b, t, where);
816}
817EXPORT_SYMBOL(bch_bset_insert);
818
819unsigned bch_btree_insert_key(struct btree_keys *b, struct bkey *k,
820 struct bkey *replace_key)
821{
822 unsigned status = BTREE_INSERT_STATUS_NO_INSERT;
823 struct bset *i = bset_tree_last(b)->data;
824 struct bkey *m, *prev = NULL;
825 struct btree_iter iter;
826
827 BUG_ON(b->ops->is_extents && !KEY_SIZE(k));
828
829 m = bch_btree_iter_init(b, &iter, b->ops->is_extents
830 ? PRECEDING_KEY(&START_KEY(k))
831 : PRECEDING_KEY(k));
832
833 if (b->ops->insert_fixup(b, k, &iter, replace_key))
834 return status;
835
836 status = BTREE_INSERT_STATUS_INSERT;
837
838 while (m != bset_bkey_last(i) &&
839 bkey_cmp(k, b->ops->is_extents ? &START_KEY(m) : m) > 0)
840 prev = m, m = bkey_next(m);
841
842 /* prev is in the tree, if we merge we're done */
843 status = BTREE_INSERT_STATUS_BACK_MERGE;
844 if (prev &&
845 bch_bkey_try_merge(b, prev, k))
846 goto merged;
847#if 0
848 status = BTREE_INSERT_STATUS_OVERWROTE;
849 if (m != bset_bkey_last(i) &&
850 KEY_PTRS(m) == KEY_PTRS(k) && !KEY_SIZE(m))
851 goto copy;
852#endif
853 status = BTREE_INSERT_STATUS_FRONT_MERGE;
854 if (m != bset_bkey_last(i) &&
855 bch_bkey_try_merge(b, k, m))
856 goto copy;
857
858 bch_bset_insert(b, m, k);
859copy: bkey_copy(m, k);
860merged:
861 return status;
862}
863EXPORT_SYMBOL(bch_btree_insert_key);
864
865/* Lookup */
866
867struct bset_search_iter {
868 struct bkey *l, *r;
869};
870
871static struct bset_search_iter bset_search_write_set(struct bset_tree *t,
872 const struct bkey *search)
873{
874 unsigned li = 0, ri = t->size;
875
876 while (li + 1 != ri) {
877 unsigned m = (li + ri) >> 1;
878
879 if (bkey_cmp(table_to_bkey(t, m), search) > 0)
880 ri = m;
881 else
882 li = m;
883 }
884
885 return (struct bset_search_iter) {
886 table_to_bkey(t, li),
887 ri < t->size ? table_to_bkey(t, ri) : bset_bkey_last(t->data)
888 };
889}
890
891static struct bset_search_iter bset_search_tree(struct bset_tree *t,
892 const struct bkey *search)
893{
894 struct bkey *l, *r;
895 struct bkey_float *f;
896 unsigned inorder, j, n = 1;
897
898 do {
899 unsigned p = n << 4;
900 p &= ((int) (p - t->size)) >> 31;
901
902 prefetch(&t->tree[p]);
903
904 j = n;
905 f = &t->tree[j];
906
907 /*
908 * n = (f->mantissa > bfloat_mantissa())
909 * ? j * 2
910 * : j * 2 + 1;
911 *
912 * We need to subtract 1 from f->mantissa for the sign bit trick
913 * to work - that's done in make_bfloat()
914 */
915 if (likely(f->exponent != 127))
916 n = j * 2 + (((unsigned)
917 (f->mantissa -
918 bfloat_mantissa(search, f))) >> 31);
919 else
920 n = (bkey_cmp(tree_to_bkey(t, j), search) > 0)
921 ? j * 2
922 : j * 2 + 1;
923 } while (n < t->size);
924
925 inorder = to_inorder(j, t);
926
927 /*
928 * n would have been the node we recursed to - the low bit tells us if
929 * we recursed left or recursed right.
930 */
931 if (n & 1) {
932 l = cacheline_to_bkey(t, inorder, f->m);
933
934 if (++inorder != t->size) {
935 f = &t->tree[inorder_next(j, t->size)];
936 r = cacheline_to_bkey(t, inorder, f->m);
937 } else
938 r = bset_bkey_last(t->data);
939 } else {
940 r = cacheline_to_bkey(t, inorder, f->m);
941
942 if (--inorder) {
943 f = &t->tree[inorder_prev(j, t->size)];
944 l = cacheline_to_bkey(t, inorder, f->m);
945 } else
946 l = t->data->start;
947 }
948
949 return (struct bset_search_iter) {l, r};
950}
951
952struct bkey *__bch_bset_search(struct btree_keys *b, struct bset_tree *t,
953 const struct bkey *search)
954{
955 struct bset_search_iter i;
956
957 /*
958 * First, we search for a cacheline, then lastly we do a linear search
959 * within that cacheline.
960 *
961 * To search for the cacheline, there's three different possibilities:
962 * * The set is too small to have a search tree, so we just do a linear
963 * search over the whole set.
964 * * The set is the one we're currently inserting into; keeping a full
965 * auxiliary search tree up to date would be too expensive, so we
966 * use a much simpler lookup table to do a binary search -
967 * bset_search_write_set().
968 * * Or we use the auxiliary search tree we constructed earlier -
969 * bset_search_tree()
970 */
971
972 if (unlikely(!t->size)) {
973 i.l = t->data->start;
974 i.r = bset_bkey_last(t->data);
975 } else if (bset_written(b, t)) {
976 /*
977 * Each node in the auxiliary search tree covers a certain range
978 * of bits, and keys above and below the set it covers might
979 * differ outside those bits - so we have to special case the
980 * start and end - handle that here:
981 */
982
983 if (unlikely(bkey_cmp(search, &t->end) >= 0))
984 return bset_bkey_last(t->data);
985
986 if (unlikely(bkey_cmp(search, t->data->start) < 0))
987 return t->data->start;
988
989 i = bset_search_tree(t, search);
990 } else {
991 BUG_ON(!b->nsets &&
992 t->size < bkey_to_cacheline(t, bset_bkey_last(t->data)));
993
994 i = bset_search_write_set(t, search);
995 }
996
997 if (btree_keys_expensive_checks(b)) {
998 BUG_ON(bset_written(b, t) &&
999 i.l != t->data->start &&
1000 bkey_cmp(tree_to_prev_bkey(t,
1001 inorder_to_tree(bkey_to_cacheline(t, i.l), t)),
1002 search) > 0);
1003
1004 BUG_ON(i.r != bset_bkey_last(t->data) &&
1005 bkey_cmp(i.r, search) <= 0);
1006 }
1007
1008 while (likely(i.l != i.r) &&
1009 bkey_cmp(i.l, search) <= 0)
1010 i.l = bkey_next(i.l);
1011
1012 return i.l;
1013}
1014EXPORT_SYMBOL(__bch_bset_search);
1015
1016/* Btree iterator */
1017
1018typedef bool (btree_iter_cmp_fn)(struct btree_iter_set,
1019 struct btree_iter_set);
1020
1021static inline bool btree_iter_cmp(struct btree_iter_set l,
1022 struct btree_iter_set r)
1023{
1024 return bkey_cmp(l.k, r.k) > 0;
1025}
1026
1027static inline bool btree_iter_end(struct btree_iter *iter)
1028{
1029 return !iter->used;
1030}
1031
1032void bch_btree_iter_push(struct btree_iter *iter, struct bkey *k,
1033 struct bkey *end)
1034{
1035 if (k != end)
1036 BUG_ON(!heap_add(iter,
1037 ((struct btree_iter_set) { k, end }),
1038 btree_iter_cmp));
1039}
1040
1041static struct bkey *__bch_btree_iter_init(struct btree_keys *b,
1042 struct btree_iter *iter,
1043 struct bkey *search,
1044 struct bset_tree *start)
1045{
1046 struct bkey *ret = NULL;
1047 iter->size = ARRAY_SIZE(iter->data);
1048 iter->used = 0;
1049
1050#ifdef CONFIG_BCACHE_DEBUG
1051 iter->b = b;
1052#endif
1053
1054 for (; start <= bset_tree_last(b); start++) {
1055 ret = bch_bset_search(b, start, search);
1056 bch_btree_iter_push(iter, ret, bset_bkey_last(start->data));
1057 }
1058
1059 return ret;
1060}
1061
1062struct bkey *bch_btree_iter_init(struct btree_keys *b,
1063 struct btree_iter *iter,
1064 struct bkey *search)
1065{
1066 return __bch_btree_iter_init(b, iter, search, b->set);
1067}
1068EXPORT_SYMBOL(bch_btree_iter_init);
1069
1070static inline struct bkey *__bch_btree_iter_next(struct btree_iter *iter,
1071 btree_iter_cmp_fn *cmp)
1072{
1073 struct btree_iter_set unused;
1074 struct bkey *ret = NULL;
1075
1076 if (!btree_iter_end(iter)) {
1077 bch_btree_iter_next_check(iter);
1078
1079 ret = iter->data->k;
1080 iter->data->k = bkey_next(iter->data->k);
1081
1082 if (iter->data->k > iter->data->end) {
1083 WARN_ONCE(1, "bset was corrupt!\n");
1084 iter->data->k = iter->data->end;
1085 }
1086
1087 if (iter->data->k == iter->data->end)
1088 heap_pop(iter, unused, cmp);
1089 else
1090 heap_sift(iter, 0, cmp);
1091 }
1092
1093 return ret;
1094}
1095
1096struct bkey *bch_btree_iter_next(struct btree_iter *iter)
1097{
1098 return __bch_btree_iter_next(iter, btree_iter_cmp);
1099
1100}
1101EXPORT_SYMBOL(bch_btree_iter_next);
1102
1103struct bkey *bch_btree_iter_next_filter(struct btree_iter *iter,
1104 struct btree_keys *b, ptr_filter_fn fn)
1105{
1106 struct bkey *ret;
1107
1108 do {
1109 ret = bch_btree_iter_next(iter);
1110 } while (ret && fn(b, ret));
1111
1112 return ret;
1113}
1114
1115/* Mergesort */
1116
1117void bch_bset_sort_state_free(struct bset_sort_state *state)
1118{
1119 if (state->pool)
1120 mempool_destroy(state->pool);
1121}
1122
1123int bch_bset_sort_state_init(struct bset_sort_state *state, unsigned page_order)
1124{
1125 spin_lock_init(&state->time.lock);
1126
1127 state->page_order = page_order;
1128 state->crit_factor = int_sqrt(1 << page_order);
1129
1130 state->pool = mempool_create_page_pool(1, page_order);
1131 if (!state->pool)
1132 return -ENOMEM;
1133
1134 return 0;
1135}
1136EXPORT_SYMBOL(bch_bset_sort_state_init);
1137
1138static void btree_mergesort(struct btree_keys *b, struct bset *out,
1139 struct btree_iter *iter,
1140 bool fixup, bool remove_stale)
1141{
1142 int i;
1143 struct bkey *k, *last = NULL;
1144 BKEY_PADDED(k) tmp;
1145 bool (*bad)(struct btree_keys *, const struct bkey *) = remove_stale
1146 ? bch_ptr_bad
1147 : bch_ptr_invalid;
1148
1149 /* Heapify the iterator, using our comparison function */
1150 for (i = iter->used / 2 - 1; i >= 0; --i)
1151 heap_sift(iter, i, b->ops->sort_cmp);
1152
1153 while (!btree_iter_end(iter)) {
1154 if (b->ops->sort_fixup && fixup)
1155 k = b->ops->sort_fixup(iter, &tmp.k);
1156 else
1157 k = NULL;
1158
1159 if (!k)
1160 k = __bch_btree_iter_next(iter, b->ops->sort_cmp);
1161
1162 if (bad(b, k))
1163 continue;
1164
1165 if (!last) {
1166 last = out->start;
1167 bkey_copy(last, k);
1168 } else if (!bch_bkey_try_merge(b, last, k)) {
1169 last = bkey_next(last);
1170 bkey_copy(last, k);
1171 }
1172 }
1173
1174 out->keys = last ? (uint64_t *) bkey_next(last) - out->d : 0;
1175
1176 pr_debug("sorted %i keys", out->keys);
1177}
1178
1179static void __btree_sort(struct btree_keys *b, struct btree_iter *iter,
1180 unsigned start, unsigned order, bool fixup,
1181 struct bset_sort_state *state)
1182{
1183 uint64_t start_time;
1184 bool used_mempool = false;
1185 struct bset *out = (void *) __get_free_pages(__GFP_NOWARN|GFP_NOWAIT,
1186 order);
1187 if (!out) {
1188 struct page *outp;
1189
1190 BUG_ON(order > state->page_order);
1191
1192 outp = mempool_alloc(state->pool, GFP_NOIO);
1193 out = page_address(outp);
1194 used_mempool = true;
1195 order = state->page_order;
1196 }
1197
1198 start_time = local_clock();
1199
1200 btree_mergesort(b, out, iter, fixup, false);
1201 b->nsets = start;
1202
1203 if (!start && order == b->page_order) {
1204 /*
1205 * Our temporary buffer is the same size as the btree node's
1206 * buffer, we can just swap buffers instead of doing a big
1207 * memcpy()
1208 */
1209
1210 out->magic = b->set->data->magic;
1211 out->seq = b->set->data->seq;
1212 out->version = b->set->data->version;
1213 swap(out, b->set->data);
1214 } else {
1215 b->set[start].data->keys = out->keys;
1216 memcpy(b->set[start].data->start, out->start,
1217 (void *) bset_bkey_last(out) - (void *) out->start);
1218 }
1219
1220 if (used_mempool)
1221 mempool_free(virt_to_page(out), state->pool);
1222 else
1223 free_pages((unsigned long) out, order);
1224
1225 bch_bset_build_written_tree(b);
1226
1227 if (!start)
1228 bch_time_stats_update(&state->time, start_time);
1229}
1230
1231void bch_btree_sort_partial(struct btree_keys *b, unsigned start,
1232 struct bset_sort_state *state)
1233{
1234 size_t order = b->page_order, keys = 0;
1235 struct btree_iter iter;
1236 int oldsize = bch_count_data(b);
1237
1238 __bch_btree_iter_init(b, &iter, NULL, &b->set[start]);
1239
1240 if (start) {
1241 unsigned i;
1242
1243 for (i = start; i <= b->nsets; i++)
1244 keys += b->set[i].data->keys;
1245
1246 order = get_order(__set_bytes(b->set->data, keys));
1247 }
1248
1249 __btree_sort(b, &iter, start, order, false, state);
1250
1251 EBUG_ON(oldsize >= 0 && bch_count_data(b) != oldsize);
1252}
1253EXPORT_SYMBOL(bch_btree_sort_partial);
1254
1255void bch_btree_sort_and_fix_extents(struct btree_keys *b,
1256 struct btree_iter *iter,
1257 struct bset_sort_state *state)
1258{
1259 __btree_sort(b, iter, 0, b->page_order, true, state);
1260}
1261
1262void bch_btree_sort_into(struct btree_keys *b, struct btree_keys *new,
1263 struct bset_sort_state *state)
1264{
1265 uint64_t start_time = local_clock();
1266
1267 struct btree_iter iter;
1268 bch_btree_iter_init(b, &iter, NULL);
1269
1270 btree_mergesort(b, new->set->data, &iter, false, true);
1271
1272 bch_time_stats_update(&state->time, start_time);
1273
1274 new->set->size = 0; // XXX: why?
1275}
1276
1277#define SORT_CRIT (4096 / sizeof(uint64_t))
1278
1279void bch_btree_sort_lazy(struct btree_keys *b, struct bset_sort_state *state)
1280{
1281 unsigned crit = SORT_CRIT;
1282 int i;
1283
1284 /* Don't sort if nothing to do */
1285 if (!b->nsets)
1286 goto out;
1287
1288 for (i = b->nsets - 1; i >= 0; --i) {
1289 crit *= state->crit_factor;
1290
1291 if (b->set[i].data->keys < crit) {
1292 bch_btree_sort_partial(b, i, state);
1293 return;
1294 }
1295 }
1296
1297 /* Sort if we'd overflow */
1298 if (b->nsets + 1 == MAX_BSETS) {
1299 bch_btree_sort(b, state);
1300 return;
1301 }
1302
1303out:
1304 bch_bset_build_written_tree(b);
1305}
1306EXPORT_SYMBOL(bch_btree_sort_lazy);
1307
1308void bch_btree_keys_stats(struct btree_keys *b, struct bset_stats *stats)
1309{
1310 unsigned i;
1311
1312 for (i = 0; i <= b->nsets; i++) {
1313 struct bset_tree *t = &b->set[i];
1314 size_t bytes = t->data->keys * sizeof(uint64_t);
1315 size_t j;
1316
1317 if (bset_written(b, t)) {
1318 stats->sets_written++;
1319 stats->bytes_written += bytes;
1320
1321 stats->floats += t->size - 1;
1322
1323 for (j = 1; j < t->size; j++)
1324 if (t->tree[j].exponent == 127)
1325 stats->failed++;
1326 } else {
1327 stats->sets_unwritten++;
1328 stats->bytes_unwritten += bytes;
1329 }
1330 }
1331}