fs/bcachefs/bset.c

   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 #include "bcachefs.h"
  10 #include "btree_cache.h"
  11 #include "bset.h"
  12 #include "eytzinger.h"
  13 #include "trace.h"
  14 #include "util.h"
  15
  16 #include <linux/unaligned.h>
  17 #include <linux/console.h>
  18 #include <linux/random.h>
  19 #include <linux/prefetch.h>
  20
  21 static inline void __bch2_btree_node_iter_advance(struct btree_node_iter *,
  22                                                   struct btree *);
  23
  24 static inline unsigned __btree_node_iter_used(struct btree_node_iter *iter)
  25 {
  26         unsigned n = ARRAY_SIZE(iter->data);
  27
  28         while (n && __btree_node_iter_set_end(iter, n - 1))
  29                 --n;
  30
  31         return n;
  32 }
  33
  34 struct bset_tree *bch2_bkey_to_bset(struct btree *b, struct bkey_packed *k)
  35 {
  36         return bch2_bkey_to_bset_inlined(b, k);
  37 }
  38
  39 /*
  40  * There are never duplicate live keys in the btree - but including keys that
  41  * have been flagged as deleted (and will be cleaned up later) we _will_ see
  42  * duplicates.
  43  *
  44  * Thus the sort order is: usual key comparison first, but for keys that compare
  45  * equal the deleted key(s) come first, and the (at most one) live version comes
  46  * last.
  47  *
  48  * The main reason for this is insertion: to handle overwrites, we first iterate
  49  * over keys that compare equal to our insert key, and then insert immediately
  50  * prior to the first key greater than the key we're inserting - our insert
  51  * position will be after all keys that compare equal to our insert key, which
  52  * by the time we actually do the insert will all be deleted.
  53  */
  54
  55 void bch2_dump_bset(struct bch_fs *c, struct btree *b,
  56                     struct bset *i, unsigned set)
  57 {
  58         struct bkey_packed *_k, *_n;
  59         struct bkey uk, n;
  60         struct bkey_s_c k;
  61         struct printbuf buf = PRINTBUF;
  62
  63         if (!i->u64s)
  64                 return;
  65
  66         for (_k = i->start;
  67              _k < vstruct_last(i);
  68              _k = _n) {
  69                 _n = bkey_p_next(_k);
  70
  71                 if (!_k->u64s) {
  72                         printk(KERN_ERR "block %u key %5zu - u64s 0? aieee!\n", set,
  73                                _k->_data - i->_data);
  74                         break;
  75                 }
  76
  77                 k = bkey_disassemble(b, _k, &uk);
  78
  79                 printbuf_reset(&buf);
  80                 if (c)
  81                         bch2_bkey_val_to_text(&buf, c, k);
  82                 else
  83                         bch2_bkey_to_text(&buf, k.k);
  84                 printk(KERN_ERR "block %u key %5zu: %s\n", set,
  85                        _k->_data - i->_data, buf.buf);
  86
  87                 if (_n == vstruct_last(i))
  88                         continue;
  89
  90                 n = bkey_unpack_key(b, _n);
  91
  92                 if (bpos_lt(n.p, k.k->p)) {
  93                         printk(KERN_ERR "Key skipped backwards\n");
  94                         continue;
  95                 }
  96
  97                 if (!bkey_deleted(k.k) && bpos_eq(n.p, k.k->p))
  98                         printk(KERN_ERR "Duplicate keys\n");
  99         }
 100
 101         printbuf_exit(&buf);
 102 }
 103
 104 void bch2_dump_btree_node(struct bch_fs *c, struct btree *b)
 105 {
 106         console_lock();
 107         for_each_bset(b, t)
 108                 bch2_dump_bset(c, b, bset(b, t), t - b->set);
 109         console_unlock();
 110 }
 111
 112 void bch2_dump_btree_node_iter(struct btree *b,
 113                               struct btree_node_iter *iter)
 114 {
 115         struct btree_node_iter_set *set;
 116         struct printbuf buf = PRINTBUF;
 117
 118         printk(KERN_ERR "btree node iter with %u/%u sets:\n",
 119                __btree_node_iter_used(iter), b->nsets);
 120
 121         btree_node_iter_for_each(iter, set) {
 122                 struct bkey_packed *k = __btree_node_offset_to_key(b, set->k);
 123                 struct bset_tree *t = bch2_bkey_to_bset(b, k);
 124                 struct bkey uk = bkey_unpack_key(b, k);
 125
 126                 printbuf_reset(&buf);
 127                 bch2_bkey_to_text(&buf, &uk);
 128                 printk(KERN_ERR "set %zu key %u: %s\n",
 129                        t - b->set, set->k, buf.buf);
 130         }
 131
 132         printbuf_exit(&buf);
 133 }
 134
 135 struct btree_nr_keys bch2_btree_node_count_keys(struct btree *b)
 136 {
 137         struct bkey_packed *k;
 138         struct btree_nr_keys nr = {};
 139
 140         for_each_bset(b, t)
 141                 bset_tree_for_each_key(b, t, k)
 142                         if (!bkey_deleted(k))
 143                                 btree_keys_account_key_add(&nr, t - b->set, k);
 144         return nr;
 145 }
 146
 147 void __bch2_verify_btree_nr_keys(struct btree *b)
 148 {
 149         struct btree_nr_keys nr = bch2_btree_node_count_keys(b);
 150
 151         BUG_ON(memcmp(&nr, &b->nr, sizeof(nr)));
 152 }
 153
 154 static void __bch2_btree_node_iter_next_check(struct btree_node_iter *_iter,
 155                                             struct btree *b)
 156 {
 157         struct btree_node_iter iter = *_iter;
 158         const struct bkey_packed *k, *n;
 159
 160         k = bch2_btree_node_iter_peek_all(&iter, b);
 161         __bch2_btree_node_iter_advance(&iter, b);
 162         n = bch2_btree_node_iter_peek_all(&iter, b);
 163
 164         bkey_unpack_key(b, k);
 165
 166         if (n &&
 167             bkey_iter_cmp(b, k, n) > 0) {
 168                 struct btree_node_iter_set *set;
 169                 struct bkey ku = bkey_unpack_key(b, k);
 170                 struct bkey nu = bkey_unpack_key(b, n);
 171                 struct printbuf buf1 = PRINTBUF;
 172                 struct printbuf buf2 = PRINTBUF;
 173
 174                 bch2_dump_btree_node(NULL, b);
 175                 bch2_bkey_to_text(&buf1, &ku);
 176                 bch2_bkey_to_text(&buf2, &nu);
 177                 printk(KERN_ERR "out of order/overlapping:\n%s\n%s\n",
 178                        buf1.buf, buf2.buf);
 179                 printk(KERN_ERR "iter was:");
 180
 181                 btree_node_iter_for_each(_iter, set) {
 182                         struct bkey_packed *k2 = __btree_node_offset_to_key(b, set->k);
 183                         struct bset_tree *t = bch2_bkey_to_bset(b, k2);
 184                         printk(" [%zi %zi]", t - b->set,
 185                                k2->_data - bset(b, t)->_data);
 186                 }
 187                 panic("\n");
 188         }
 189 }
 190
 191 void __bch2_btree_node_iter_verify(struct btree_node_iter *iter,
 192                                    struct btree *b)
 193 {
 194         struct btree_node_iter_set *set, *s2;
 195         struct bkey_packed *k, *p;
 196
 197         if (bch2_btree_node_iter_end(iter))
 198                 return;
 199
 200         /* Verify no duplicates: */
 201         btree_node_iter_for_each(iter, set) {
 202                 BUG_ON(set->k > set->end);
 203                 btree_node_iter_for_each(iter, s2)
 204                         BUG_ON(set != s2 && set->end == s2->end);
 205         }
 206
 207         /* Verify that set->end is correct: */
 208         btree_node_iter_for_each(iter, set) {
 209                 for_each_bset(b, t)
 210                         if (set->end == t->end_offset) {
 211                                 BUG_ON(set->k < btree_bkey_first_offset(t) ||
 212                                        set->k >= t->end_offset);
 213                                 goto found;
 214                         }
 215                 BUG();
 216 found:
 217                 do {} while (0);
 218         }
 219
 220         /* Verify iterator is sorted: */
 221         btree_node_iter_for_each(iter, set)
 222                 BUG_ON(set != iter->data &&
 223                        btree_node_iter_cmp(b, set[-1], set[0]) > 0);
 224
 225         k = bch2_btree_node_iter_peek_all(iter, b);
 226
 227         for_each_bset(b, t) {
 228                 if (iter->data[0].end == t->end_offset)
 229                         continue;
 230
 231                 p = bch2_bkey_prev_all(b, t,
 232                         bch2_btree_node_iter_bset_pos(iter, b, t));
 233
 234                 BUG_ON(p && bkey_iter_cmp(b, k, p) < 0);
 235         }
 236 }
 237
 238 static void __bch2_verify_insert_pos(struct btree *b, struct bkey_packed *where,
 239                                      struct bkey_packed *insert, unsigned clobber_u64s)
 240 {
 241         struct bset_tree *t = bch2_bkey_to_bset(b, where);
 242         struct bkey_packed *prev = bch2_bkey_prev_all(b, t, where);
 243         struct bkey_packed *next = (void *) ((u64 *) where->_data + clobber_u64s);
 244         struct printbuf buf1 = PRINTBUF;
 245         struct printbuf buf2 = PRINTBUF;
 246 #if 0
 247         BUG_ON(prev &&
 248                bkey_iter_cmp(b, prev, insert) > 0);
 249 #else
 250         if (prev &&
 251             bkey_iter_cmp(b, prev, insert) > 0) {
 252                 struct bkey k1 = bkey_unpack_key(b, prev);
 253                 struct bkey k2 = bkey_unpack_key(b, insert);
 254
 255                 bch2_dump_btree_node(NULL, b);
 256                 bch2_bkey_to_text(&buf1, &k1);
 257                 bch2_bkey_to_text(&buf2, &k2);
 258
 259                 panic("prev > insert:\n"
 260                       "prev    key %s\n"
 261                       "insert  key %s\n",
 262                       buf1.buf, buf2.buf);
 263         }
 264 #endif
 265 #if 0
 266         BUG_ON(next != btree_bkey_last(b, t) &&
 267                bkey_iter_cmp(b, insert, next) > 0);
 268 #else
 269         if (next != btree_bkey_last(b, t) &&
 270             bkey_iter_cmp(b, insert, next) > 0) {
 271                 struct bkey k1 = bkey_unpack_key(b, insert);
 272                 struct bkey k2 = bkey_unpack_key(b, next);
 273
 274                 bch2_dump_btree_node(NULL, b);
 275                 bch2_bkey_to_text(&buf1, &k1);
 276                 bch2_bkey_to_text(&buf2, &k2);
 277
 278                 panic("insert > next:\n"
 279                       "insert  key %s\n"
 280                       "next    key %s\n",
 281                       buf1.buf, buf2.buf);
 282         }
 283 #endif
 284 }
 285
 286 static inline void bch2_verify_insert_pos(struct btree *b,
 287                                           struct bkey_packed *where,
 288                                           struct bkey_packed *insert,
 289                                           unsigned clobber_u64s)
 290 {
 291         if (static_branch_unlikely(&bch2_debug_check_bset_lookups))
 292                 __bch2_verify_insert_pos(b, where, insert, clobber_u64s);
 293 }
 294
 295
 296 /* Auxiliary search trees */
 297
 298 #define BFLOAT_FAILED_UNPACKED  U8_MAX
 299 #define BFLOAT_FAILED           U8_MAX
 300
 301 struct bkey_float {
 302         u8              exponent;
 303         u8              key_offset;
 304         u16             mantissa;
 305 };
 306 #define BKEY_MANTISSA_BITS      16
 307
 308 struct ro_aux_tree {
 309         u8                      nothing[0];
 310         struct bkey_float       f[];
 311 };
 312
 313 struct rw_aux_tree {
 314         u16             offset;
 315         struct bpos     k;
 316 };
 317
 318 static unsigned bset_aux_tree_buf_end(const struct bset_tree *t)
 319 {
 320         BUG_ON(t->aux_data_offset == U16_MAX);
 321
 322         switch (bset_aux_tree_type(t)) {
 323         case BSET_NO_AUX_TREE:
 324                 return t->aux_data_offset;
 325         case BSET_RO_AUX_TREE:
 326                 return t->aux_data_offset +
 327                         DIV_ROUND_UP(t->size * sizeof(struct bkey_float), 8);
 328         case BSET_RW_AUX_TREE:
 329                 return t->aux_data_offset +
 330                         DIV_ROUND_UP(sizeof(struct rw_aux_tree) * t->size, 8);
 331         default:
 332                 BUG();
 333         }
 334 }
 335
 336 static unsigned bset_aux_tree_buf_start(const struct btree *b,
 337                                         const struct bset_tree *t)
 338 {
 339         return t == b->set
 340                 ? DIV_ROUND_UP(b->unpack_fn_len, 8)
 341                 : bset_aux_tree_buf_end(t - 1);
 342 }
 343
 344 static void *__aux_tree_base(const struct btree *b,
 345                              const struct bset_tree *t)
 346 {
 347         return b->aux_data + t->aux_data_offset * 8;
 348 }
 349
 350 static struct ro_aux_tree *ro_aux_tree_base(const struct btree *b,
 351                                             const struct bset_tree *t)
 352 {
 353         EBUG_ON(bset_aux_tree_type(t) != BSET_RO_AUX_TREE);
 354
 355         return __aux_tree_base(b, t);
 356 }
 357
 358 static struct bkey_float *bkey_float(const struct btree *b,
 359                                      const struct bset_tree *t,
 360                                      unsigned idx)
 361 {
 362         return ro_aux_tree_base(b, t)->f + idx;
 363 }
 364
 365 static void __bset_aux_tree_verify(struct btree *b)
 366 {
 367         for_each_bset(b, t) {
 368                 if (t->aux_data_offset == U16_MAX)
 369                         continue;
 370
 371                 BUG_ON(t != b->set &&
 372                        t[-1].aux_data_offset == U16_MAX);
 373
 374                 BUG_ON(t->aux_data_offset < bset_aux_tree_buf_start(b, t));
 375                 BUG_ON(t->aux_data_offset > btree_aux_data_u64s(b));
 376                 BUG_ON(bset_aux_tree_buf_end(t) > btree_aux_data_u64s(b));
 377         }
 378 }
 379
 380 static inline void bset_aux_tree_verify(struct btree *b)
 381 {
 382         if (static_branch_unlikely(&bch2_debug_check_bset_lookups))
 383                 __bset_aux_tree_verify(b);
 384 }
 385
 386 void bch2_btree_keys_init(struct btree *b)
 387 {
 388         unsigned i;
 389
 390         b->nsets                = 0;
 391         memset(&b->nr, 0, sizeof(b->nr));
 392
 393         for (i = 0; i < MAX_BSETS; i++)
 394                 b->set[i].data_offset = U16_MAX;
 395
 396         bch2_bset_set_no_aux_tree(b, b->set);
 397 }
 398
 399 /* Binary tree stuff for auxiliary search trees */
 400
 401 /*
 402  * Cacheline/offset <-> bkey pointer arithmetic:
 403  *
 404  * t->tree is a binary search tree in an array; each node corresponds to a key
 405  * in one cacheline in t->set (BSET_CACHELINE bytes).
 406  *
 407  * This means we don't have to store the full index of the key that a node in
 408  * the binary tree points to; eytzinger1_to_inorder() gives us the cacheline, and
 409  * then bkey_float->m gives us the offset within that cacheline, in units of 8
 410  * bytes.
 411  *
 412  * cacheline_to_bkey() and friends abstract out all the pointer arithmetic to
 413  * make this work.
 414  *
 415  * To construct the bfloat for an arbitrary key we need to know what the key
 416  * immediately preceding it is: we have to check if the two keys differ in the
 417  * bits we're going to store in bkey_float->mantissa. t->prev[j] stores the size
 418  * of the previous key so we can walk backwards to it from t->tree[j]'s key.
 419  */
 420
 421 static inline void *bset_cacheline(const struct btree *b,
 422                                    const struct bset_tree *t,
 423                                    unsigned cacheline)
 424 {
 425         return (void *) round_down((unsigned long) btree_bkey_first(b, t),
 426                                    L1_CACHE_BYTES) +
 427                 cacheline * BSET_CACHELINE;
 428 }
 429
 430 static struct bkey_packed *cacheline_to_bkey(const struct btree *b,
 431                                              const struct bset_tree *t,
 432                                              unsigned cacheline,
 433                                              unsigned offset)
 434 {
 435         return bset_cacheline(b, t, cacheline) + offset * 8;
 436 }
 437
 438 static unsigned bkey_to_cacheline(const struct btree *b,
 439                                   const struct bset_tree *t,
 440                                   const struct bkey_packed *k)
 441 {
 442         return ((void *) k - bset_cacheline(b, t, 0)) / BSET_CACHELINE;
 443 }
 444
 445 static ssize_t __bkey_to_cacheline_offset(const struct btree *b,
 446                                           const struct bset_tree *t,
 447                                           unsigned cacheline,
 448                                           const struct bkey_packed *k)
 449 {
 450         return (u64 *) k - (u64 *) bset_cacheline(b, t, cacheline);
 451 }
 452
 453 static unsigned bkey_to_cacheline_offset(const struct btree *b,
 454                                          const struct bset_tree *t,
 455                                          unsigned cacheline,
 456                                          const struct bkey_packed *k)
 457 {
 458         size_t m = __bkey_to_cacheline_offset(b, t, cacheline, k);
 459
 460         EBUG_ON(m > U8_MAX);
 461         return m;
 462 }
 463
 464 static inline struct bkey_packed *tree_to_bkey(const struct btree *b,
 465                                                const struct bset_tree *t,
 466                                                unsigned j)
 467 {
 468         return cacheline_to_bkey(b, t,
 469                         __eytzinger1_to_inorder(j, t->size - 1, t->extra),
 470                         bkey_float(b, t, j)->key_offset);
 471 }
 472
 473 static struct rw_aux_tree *rw_aux_tree(const struct btree *b,
 474                                        const struct bset_tree *t)
 475 {
 476         EBUG_ON(bset_aux_tree_type(t) != BSET_RW_AUX_TREE);
 477
 478         return __aux_tree_base(b, t);
 479 }
 480
 481 /*
 482  * For the write set - the one we're currently inserting keys into - we don't
 483  * maintain a full search tree, we just keep a simple lookup table in t->prev.
 484  */
 485 static struct bkey_packed *rw_aux_to_bkey(const struct btree *b,
 486                                           struct bset_tree *t,
 487                                           unsigned j)
 488 {
 489         return __btree_node_offset_to_key(b, rw_aux_tree(b, t)[j].offset);
 490 }
 491
 492 static void rw_aux_tree_set(const struct btree *b, struct bset_tree *t,
 493                             unsigned j, struct bkey_packed *k)
 494 {
 495         EBUG_ON(k >= btree_bkey_last(b, t));
 496
 497         rw_aux_tree(b, t)[j] = (struct rw_aux_tree) {
 498                 .offset = __btree_node_key_to_offset(b, k),
 499                 .k      = bkey_unpack_pos(b, k),
 500         };
 501 }
 502
 503 static void __bch2_bset_verify_rw_aux_tree(struct btree *b, struct bset_tree *t)
 504 {
 505         struct bkey_packed *k = btree_bkey_first(b, t);
 506         unsigned j = 0;
 507
 508         BUG_ON(bset_has_ro_aux_tree(t));
 509
 510         if (!bset_has_rw_aux_tree(t))
 511                 return;
 512
 513         BUG_ON(t->size < 1);
 514         BUG_ON(rw_aux_to_bkey(b, t, j) != k);
 515
 516         goto start;
 517         while (1) {
 518                 if (rw_aux_to_bkey(b, t, j) == k) {
 519                         BUG_ON(!bpos_eq(rw_aux_tree(b, t)[j].k,
 520                                         bkey_unpack_pos(b, k)));
 521 start:
 522                         if (++j == t->size)
 523                                 break;
 524
 525                         BUG_ON(rw_aux_tree(b, t)[j].offset <=
 526                                rw_aux_tree(b, t)[j - 1].offset);
 527                 }
 528
 529                 k = bkey_p_next(k);
 530                 BUG_ON(k >= btree_bkey_last(b, t));
 531         }
 532 }
 533
 534 static inline void bch2_bset_verify_rw_aux_tree(struct btree *b,
 535                                                 struct bset_tree *t)
 536 {
 537         if (static_branch_unlikely(&bch2_debug_check_bset_lookups))
 538                 __bch2_bset_verify_rw_aux_tree(b, t);
 539 }
 540
 541 /* returns idx of first entry >= offset: */
 542 static unsigned rw_aux_tree_bsearch(struct btree *b,
 543                                     struct bset_tree *t,
 544                                     unsigned offset)
 545 {
 546         unsigned bset_offs = offset - btree_bkey_first_offset(t);
 547         unsigned bset_u64s = t->end_offset - btree_bkey_first_offset(t);
 548         unsigned idx = bset_u64s ? bset_offs * t->size / bset_u64s : 0;
 549
 550         EBUG_ON(bset_aux_tree_type(t) != BSET_RW_AUX_TREE);
 551         EBUG_ON(!t->size);
 552         EBUG_ON(idx > t->size);
 553
 554         while (idx < t->size &&
 555                rw_aux_tree(b, t)[idx].offset < offset)
 556                 idx++;
 557
 558         while (idx &&
 559                rw_aux_tree(b, t)[idx - 1].offset >= offset)
 560                 idx--;
 561
 562         EBUG_ON(idx < t->size &&
 563                 rw_aux_tree(b, t)[idx].offset < offset);
 564         EBUG_ON(idx && rw_aux_tree(b, t)[idx - 1].offset >= offset);
 565         EBUG_ON(idx + 1 < t->size &&
 566                 rw_aux_tree(b, t)[idx].offset ==
 567                 rw_aux_tree(b, t)[idx + 1].offset);
 568
 569         return idx;
 570 }
 571
 572 static inline unsigned bkey_mantissa(const struct bkey_packed *k,
 573                                      const struct bkey_float *f)
 574 {
 575         u64 v;
 576
 577         EBUG_ON(!bkey_packed(k));
 578
 579         v = get_unaligned((u64 *) (((u8 *) k->_data) + (f->exponent >> 3)));
 580
 581         /*
 582          * In little endian, we're shifting off low bits (and then the bits we
 583          * want are at the low end), in big endian we're shifting off high bits
 584          * (and then the bits we want are at the high end, so we shift them
 585          * back down):
 586          */
 587 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 588         v >>= f->exponent & 7;
 589 #else
 590         v >>= 64 - (f->exponent & 7) - BKEY_MANTISSA_BITS;
 591 #endif
 592         return (u16) v;
 593 }
 594
 595 static __always_inline void make_bfloat(struct btree *b, struct bset_tree *t,
 596                                         unsigned j,
 597                                         struct bkey_packed *min_key,
 598                                         struct bkey_packed *max_key)
 599 {
 600         struct bkey_float *f = bkey_float(b, t, j);
 601         struct bkey_packed *m = tree_to_bkey(b, t, j);
 602         struct bkey_packed *l = is_power_of_2(j)
 603                 ? min_key
 604                 : tree_to_bkey(b, t, j >> ffs(j));
 605         struct bkey_packed *r = is_power_of_2(j + 1)
 606                 ? max_key
 607                 : tree_to_bkey(b, t, j >> (ffz(j) + 1));
 608         unsigned mantissa;
 609         int shift, exponent, high_bit;
 610
 611         /*
 612          * for failed bfloats, the lookup code falls back to comparing against
 613          * the original key.
 614          */
 615
 616         if (!bkey_packed(l) || !bkey_packed(r) || !bkey_packed(m) ||
 617             !b->nr_key_bits) {
 618                 f->exponent = BFLOAT_FAILED_UNPACKED;
 619                 return;
 620         }
 621
 622         /*
 623          * The greatest differing bit of l and r is the first bit we must
 624          * include in the bfloat mantissa we're creating in order to do
 625          * comparisons - that bit always becomes the high bit of
 626          * bfloat->mantissa, and thus the exponent we're calculating here is
 627          * the position of what will become the low bit in bfloat->mantissa:
 628          *
 629          * Note that this may be negative - we may be running off the low end
 630          * of the key: we handle this later:
 631          */
 632         high_bit = max(bch2_bkey_greatest_differing_bit(b, l, r),
 633                        min_t(unsigned, BKEY_MANTISSA_BITS, b->nr_key_bits) - 1);
 634         exponent = high_bit - (BKEY_MANTISSA_BITS - 1);
 635
 636         /*
 637          * Then we calculate the actual shift value, from the start of the key
 638          * (k->_data), to get the key bits starting at exponent:
 639          */
 640 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 641         shift = (int) (b->format.key_u64s * 64 - b->nr_key_bits) + exponent;
 642
 643         EBUG_ON(shift + BKEY_MANTISSA_BITS > b->format.key_u64s * 64);
 644 #else
 645         shift = high_bit_offset +
 646                 b->nr_key_bits -
 647                 exponent -
 648                 BKEY_MANTISSA_BITS;
 649
 650         EBUG_ON(shift < KEY_PACKED_BITS_START);
 651 #endif
 652         EBUG_ON(shift < 0 || shift >= BFLOAT_FAILED);
 653
 654         f->exponent = shift;
 655         mantissa = bkey_mantissa(m, f);
 656
 657         /*
 658          * If we've got garbage bits, set them to all 1s - it's legal for the
 659          * bfloat to compare larger than the original key, but not smaller:
 660          */
 661         if (exponent < 0)
 662                 mantissa |= ~(~0U << -exponent);
 663
 664         f->mantissa = mantissa;
 665 }
 666
 667 /* bytes remaining - only valid for last bset: */
 668 static unsigned __bset_tree_capacity(struct btree *b, const struct bset_tree *t)
 669 {
 670         bset_aux_tree_verify(b);
 671
 672         return btree_aux_data_bytes(b) - t->aux_data_offset * sizeof(u64);
 673 }
 674
 675 static unsigned bset_ro_tree_capacity(struct btree *b, const struct bset_tree *t)
 676 {
 677         return __bset_tree_capacity(b, t) / sizeof(struct bkey_float);
 678 }
 679
 680 static unsigned bset_rw_tree_capacity(struct btree *b, const struct bset_tree *t)
 681 {
 682         return __bset_tree_capacity(b, t) / sizeof(struct rw_aux_tree);
 683 }
 684
 685 static noinline void __build_rw_aux_tree(struct btree *b, struct bset_tree *t)
 686 {
 687         struct bkey_packed *k;
 688
 689         t->size = 1;
 690         t->extra = BSET_RW_AUX_TREE_VAL;
 691         rw_aux_tree(b, t)[0].offset =
 692                 __btree_node_key_to_offset(b, btree_bkey_first(b, t));
 693
 694         bset_tree_for_each_key(b, t, k) {
 695                 if (t->size == bset_rw_tree_capacity(b, t))
 696                         break;
 697
 698                 if ((void *) k - (void *) rw_aux_to_bkey(b, t, t->size - 1) >
 699                     L1_CACHE_BYTES)
 700                         rw_aux_tree_set(b, t, t->size++, k);
 701         }
 702 }
 703
 704 static noinline void __build_ro_aux_tree(struct btree *b, struct bset_tree *t)
 705 {
 706         struct bkey_packed *k = btree_bkey_first(b, t);
 707         struct bkey_i min_key, max_key;
 708         unsigned cacheline = 1;
 709
 710         t->size = min(bkey_to_cacheline(b, t, btree_bkey_last(b, t)),
 711                       bset_ro_tree_capacity(b, t));
 712 retry:
 713         if (t->size < 2) {
 714                 t->size = 0;
 715                 t->extra = BSET_NO_AUX_TREE_VAL;
 716                 return;
 717         }
 718
 719         t->extra = eytzinger1_extra(t->size - 1);
 720
 721         /* First we figure out where the first key in each cacheline is */
 722         eytzinger1_for_each(j, t->size - 1) {
 723                 while (bkey_to_cacheline(b, t, k) < cacheline)
 724                         k = bkey_p_next(k);
 725
 726                 if (k >= btree_bkey_last(b, t)) {
 727                         /* XXX: this path sucks */
 728                         t->size--;
 729                         goto retry;
 730                 }
 731
 732                 bkey_float(b, t, j)->key_offset =
 733                         bkey_to_cacheline_offset(b, t, cacheline++, k);
 734
 735                 EBUG_ON(tree_to_bkey(b, t, j) != k);
 736         }
 737
 738         if (!bkey_pack_pos(bkey_to_packed(&min_key), b->data->min_key, b)) {
 739                 bkey_init(&min_key.k);
 740                 min_key.k.p = b->data->min_key;
 741         }
 742
 743         if (!bkey_pack_pos(bkey_to_packed(&max_key), b->data->max_key, b)) {
 744                 bkey_init(&max_key.k);
 745                 max_key.k.p = b->data->max_key;
 746         }
 747
 748         /* Then we build the tree */
 749         eytzinger1_for_each(j, t->size - 1)
 750                 make_bfloat(b, t, j,
 751                             bkey_to_packed(&min_key),
 752                             bkey_to_packed(&max_key));
 753 }
 754
 755 static void bset_alloc_tree(struct btree *b, struct bset_tree *t)
 756 {
 757         struct bset_tree *i;
 758
 759         for (i = b->set; i != t; i++)
 760                 BUG_ON(bset_has_rw_aux_tree(i));
 761
 762         bch2_bset_set_no_aux_tree(b, t);
 763
 764         /* round up to next cacheline: */
 765         t->aux_data_offset = round_up(bset_aux_tree_buf_start(b, t),
 766                                       SMP_CACHE_BYTES / sizeof(u64));
 767
 768         bset_aux_tree_verify(b);
 769 }
 770
 771 void bch2_bset_build_aux_tree(struct btree *b, struct bset_tree *t,
 772                              bool writeable)
 773 {
 774         if (writeable
 775             ? bset_has_rw_aux_tree(t)
 776             : bset_has_ro_aux_tree(t))
 777                 return;
 778
 779         bset_alloc_tree(b, t);
 780
 781         if (!__bset_tree_capacity(b, t))
 782                 return;
 783
 784         if (writeable)
 785                 __build_rw_aux_tree(b, t);
 786         else
 787                 __build_ro_aux_tree(b, t);
 788
 789         bset_aux_tree_verify(b);
 790 }
 791
 792 void bch2_bset_init_first(struct btree *b, struct bset *i)
 793 {
 794         struct bset_tree *t;
 795
 796         BUG_ON(b->nsets);
 797
 798         memset(i, 0, sizeof(*i));
 799         get_random_bytes(&i->seq, sizeof(i->seq));
 800         SET_BSET_BIG_ENDIAN(i, CPU_BIG_ENDIAN);
 801
 802         t = &b->set[b->nsets++];
 803         set_btree_bset(b, t, i);
 804 }
 805
 806 void bch2_bset_init_next(struct btree *b, struct btree_node_entry *bne)
 807 {
 808         struct bset *i = &bne->keys;
 809         struct bset_tree *t;
 810
 811         BUG_ON(bset_byte_offset(b, bne) >= btree_buf_bytes(b));
 812         BUG_ON((void *) bne < (void *) btree_bkey_last(b, bset_tree_last(b)));
 813         BUG_ON(b->nsets >= MAX_BSETS);
 814
 815         memset(i, 0, sizeof(*i));
 816         i->seq = btree_bset_first(b)->seq;
 817         SET_BSET_BIG_ENDIAN(i, CPU_BIG_ENDIAN);
 818
 819         t = &b->set[b->nsets++];
 820         set_btree_bset(b, t, i);
 821 }
 822
 823 /*
 824  * find _some_ key in the same bset as @k that precedes @k - not necessarily the
 825  * immediate predecessor:
 826  */
 827 static struct bkey_packed *__bkey_prev(struct btree *b, struct bset_tree *t,
 828                                        struct bkey_packed *k)
 829 {
 830         struct bkey_packed *p;
 831         unsigned offset;
 832         int j;
 833
 834         EBUG_ON(k < btree_bkey_first(b, t) ||
 835                 k > btree_bkey_last(b, t));
 836
 837         if (k == btree_bkey_first(b, t))
 838                 return NULL;
 839
 840         switch (bset_aux_tree_type(t)) {
 841         case BSET_NO_AUX_TREE:
 842                 p = btree_bkey_first(b, t);
 843                 break;
 844         case BSET_RO_AUX_TREE:
 845                 j = min_t(unsigned, t->size - 1, bkey_to_cacheline(b, t, k));
 846
 847                 do {
 848                         p = j ? tree_to_bkey(b, t,
 849                                         __inorder_to_eytzinger1(j--,
 850                                                         t->size - 1, t->extra))
 851                               : btree_bkey_first(b, t);
 852                 } while (p >= k);
 853                 break;
 854         case BSET_RW_AUX_TREE:
 855                 offset = __btree_node_key_to_offset(b, k);
 856                 j = rw_aux_tree_bsearch(b, t, offset);
 857                 p = j ? rw_aux_to_bkey(b, t, j - 1)
 858                       : btree_bkey_first(b, t);
 859                 break;
 860         }
 861
 862         return p;
 863 }
 864
 865 struct bkey_packed *bch2_bkey_prev_filter(struct btree *b,
 866                                           struct bset_tree *t,
 867                                           struct bkey_packed *k,
 868                                           unsigned min_key_type)
 869 {
 870         struct bkey_packed *p, *i, *ret = NULL, *orig_k = k;
 871
 872         while ((p = __bkey_prev(b, t, k)) && !ret) {
 873                 for (i = p; i != k; i = bkey_p_next(i))
 874                         if (i->type >= min_key_type)
 875                                 ret = i;
 876
 877                 k = p;
 878         }
 879
 880         if (static_branch_unlikely(&bch2_debug_check_bset_lookups)) {
 881                 BUG_ON(ret >= orig_k);
 882
 883                 for (i = ret
 884                         ? bkey_p_next(ret)
 885                         : btree_bkey_first(b, t);
 886                      i != orig_k;
 887                      i = bkey_p_next(i))
 888                         BUG_ON(i->type >= min_key_type);
 889         }
 890
 891         return ret;
 892 }
 893
 894 /* Insert */
 895
 896 static void rw_aux_tree_insert_entry(struct btree *b,
 897                                      struct bset_tree *t,
 898                                      unsigned idx)
 899 {
 900         EBUG_ON(!idx || idx > t->size);
 901         struct bkey_packed *start = rw_aux_to_bkey(b, t, idx - 1);
 902         struct bkey_packed *end = idx < t->size
 903                                   ? rw_aux_to_bkey(b, t, idx)
 904                                   : btree_bkey_last(b, t);
 905
 906         if (t->size < bset_rw_tree_capacity(b, t) &&
 907             (void *) end - (void *) start > L1_CACHE_BYTES) {
 908                 struct bkey_packed *k = start;
 909
 910                 while (1) {
 911                         k = bkey_p_next(k);
 912                         if (k == end)
 913                                 break;
 914
 915                         if ((void *) k - (void *) start >= L1_CACHE_BYTES) {
 916                                 memmove(&rw_aux_tree(b, t)[idx + 1],
 917                                         &rw_aux_tree(b, t)[idx],
 918                                         (void *) &rw_aux_tree(b, t)[t->size] -
 919                                         (void *) &rw_aux_tree(b, t)[idx]);
 920                                 t->size++;
 921                                 rw_aux_tree_set(b, t, idx, k);
 922                                 break;
 923                         }
 924                 }
 925         }
 926 }
 927
 928 static void bch2_bset_fix_lookup_table(struct btree *b,
 929                                        struct bset_tree *t,
 930                                        struct bkey_packed *_where,
 931                                        unsigned clobber_u64s,
 932                                        unsigned new_u64s)
 933 {
 934         int shift = new_u64s - clobber_u64s;
 935         unsigned idx, j, where = __btree_node_key_to_offset(b, _where);
 936
 937         EBUG_ON(bset_has_ro_aux_tree(t));
 938
 939         if (!bset_has_rw_aux_tree(t))
 940                 return;
 941
 942         if (where > rw_aux_tree(b, t)[t->size - 1].offset) {
 943                 rw_aux_tree_insert_entry(b, t, t->size);
 944                 goto verify;
 945         }
 946
 947         /* returns first entry >= where */
 948         idx = rw_aux_tree_bsearch(b, t, where);
 949
 950         if (rw_aux_tree(b, t)[idx].offset == where) {
 951                 if (!idx) { /* never delete first entry */
 952                         idx++;
 953                 } else if (where < t->end_offset) {
 954                         rw_aux_tree_set(b, t, idx++, _where);
 955                 } else {
 956                         EBUG_ON(where != t->end_offset);
 957                         rw_aux_tree_insert_entry(b, t, --t->size);
 958                         goto verify;
 959                 }
 960         }
 961
 962         EBUG_ON(idx < t->size && rw_aux_tree(b, t)[idx].offset <= where);
 963         if (idx < t->size &&
 964             rw_aux_tree(b, t)[idx].offset + shift ==
 965             rw_aux_tree(b, t)[idx - 1].offset) {
 966                 memmove(&rw_aux_tree(b, t)[idx],
 967                         &rw_aux_tree(b, t)[idx + 1],
 968                         (void *) &rw_aux_tree(b, t)[t->size] -
 969                         (void *) &rw_aux_tree(b, t)[idx + 1]);
 970                 t->size -= 1;
 971         }
 972
 973         for (j = idx; j < t->size; j++)
 974                 rw_aux_tree(b, t)[j].offset += shift;
 975
 976         EBUG_ON(idx < t->size &&
 977                 rw_aux_tree(b, t)[idx].offset ==
 978                 rw_aux_tree(b, t)[idx - 1].offset);
 979
 980         rw_aux_tree_insert_entry(b, t, idx);
 981
 982 verify:
 983         bch2_bset_verify_rw_aux_tree(b, t);
 984         bset_aux_tree_verify(b);
 985 }
 986
 987 void bch2_bset_insert(struct btree *b,
 988                       struct bkey_packed *where,
 989                       struct bkey_i *insert,
 990                       unsigned clobber_u64s)
 991 {
 992         struct bkey_format *f = &b->format;
 993         struct bset_tree *t = bset_tree_last(b);
 994         struct bkey_packed packed, *src = bkey_to_packed(insert);
 995
 996         bch2_bset_verify_rw_aux_tree(b, t);
 997         bch2_verify_insert_pos(b, where, bkey_to_packed(insert), clobber_u64s);
 998
 999         if (bch2_bkey_pack_key(&packed, &insert->k, f))
1000                 src = &packed;
1001
1002         if (!bkey_deleted(&insert->k))
1003                 btree_keys_account_key_add(&b->nr, t - b->set, src);
1004
1005         if (src->u64s != clobber_u64s) {
1006                 u64 *src_p = (u64 *) where->_data + clobber_u64s;
1007                 u64 *dst_p = (u64 *) where->_data + src->u64s;
1008
1009                 EBUG_ON((int) le16_to_cpu(bset(b, t)->u64s) <
1010                         (int) clobber_u64s - src->u64s);
1011
1012                 memmove_u64s(dst_p, src_p, btree_bkey_last(b, t)->_data - src_p);
1013                 le16_add_cpu(&bset(b, t)->u64s, src->u64s - clobber_u64s);
1014                 set_btree_bset_end(b, t);
1015         }
1016
1017         memcpy_u64s_small(where, src,
1018                     bkeyp_key_u64s(f, src));
1019         memcpy_u64s(bkeyp_val(f, where), &insert->v,
1020                     bkeyp_val_u64s(f, src));
1021
1022         if (src->u64s != clobber_u64s)
1023                 bch2_bset_fix_lookup_table(b, t, where, clobber_u64s, src->u64s);
1024
1025         bch2_verify_btree_nr_keys(b);
1026 }
1027
1028 void bch2_bset_delete(struct btree *b,
1029                       struct bkey_packed *where,
1030                       unsigned clobber_u64s)
1031 {
1032         struct bset_tree *t = bset_tree_last(b);
1033         u64 *src_p = (u64 *) where->_data + clobber_u64s;
1034         u64 *dst_p = where->_data;
1035
1036         bch2_bset_verify_rw_aux_tree(b, t);
1037
1038         EBUG_ON(le16_to_cpu(bset(b, t)->u64s) < clobber_u64s);
1039
1040         memmove_u64s_down(dst_p, src_p, btree_bkey_last(b, t)->_data - src_p);
1041         le16_add_cpu(&bset(b, t)->u64s, -clobber_u64s);
1042         set_btree_bset_end(b, t);
1043
1044         bch2_bset_fix_lookup_table(b, t, where, clobber_u64s, 0);
1045 }
1046
1047 /* Lookup */
1048
1049 __flatten
1050 static struct bkey_packed *bset_search_write_set(const struct btree *b,
1051                                 struct bset_tree *t,
1052                                 struct bpos *search)
1053 {
1054         unsigned l = 0, r = t->size;
1055
1056         while (l + 1 != r) {
1057                 unsigned m = (l + r) >> 1;
1058
1059                 if (bpos_lt(rw_aux_tree(b, t)[m].k, *search))
1060                         l = m;
1061                 else
1062                         r = m;
1063         }
1064
1065         return rw_aux_to_bkey(b, t, l);
1066 }
1067
1068 static inline void prefetch_four_cachelines(void *p)
1069 {
1070 #ifdef CONFIG_X86_64
1071         asm("prefetcht0 (-127 + 64 * 0)(%0);"
1072             "prefetcht0 (-127 + 64 * 1)(%0);"
1073             "prefetcht0 (-127 + 64 * 2)(%0);"
1074             "prefetcht0 (-127 + 64 * 3)(%0);"
1075             :
1076             : "r" (p + 127));
1077 #else
1078         prefetch(p + L1_CACHE_BYTES * 0);
1079         prefetch(p + L1_CACHE_BYTES * 1);
1080         prefetch(p + L1_CACHE_BYTES * 2);
1081         prefetch(p + L1_CACHE_BYTES * 3);
1082 #endif
1083 }
1084
1085 static inline bool bkey_mantissa_bits_dropped(const struct btree *b,
1086                                               const struct bkey_float *f)
1087 {
1088 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
1089         unsigned key_bits_start = b->format.key_u64s * 64 - b->nr_key_bits;
1090
1091         return f->exponent > key_bits_start;
1092 #else
1093         unsigned key_bits_end = high_bit_offset + b->nr_key_bits;
1094
1095         return f->exponent + BKEY_MANTISSA_BITS < key_bits_end;
1096 #endif
1097 }
1098
1099 __flatten
1100 static struct bkey_packed *bset_search_tree(const struct btree *b,
1101                                 const struct bset_tree *t,
1102                                 const struct bpos *search,
1103                                 const struct bkey_packed *packed_search)
1104 {
1105         struct ro_aux_tree *base = ro_aux_tree_base(b, t);
1106         struct bkey_float *f;
1107         struct bkey_packed *k;
1108         unsigned inorder, n = 1, l, r;
1109         int cmp;
1110
1111         do {
1112                 if (likely(n << 4 < t->size))
1113                         prefetch(&base->f[n << 4]);
1114
1115                 f = &base->f[n];
1116                 if (unlikely(f->exponent >= BFLOAT_FAILED))
1117                         goto slowpath;
1118
1119                 l = f->mantissa;
1120                 r = bkey_mantissa(packed_search, f);
1121
1122                 if (unlikely(l == r) && bkey_mantissa_bits_dropped(b, f))
1123                         goto slowpath;
1124
1125                 n = n * 2 + (l < r);
1126                 continue;
1127 slowpath:
1128                 k = tree_to_bkey(b, t, n);
1129                 cmp = bkey_cmp_p_or_unp(b, k, packed_search, search);
1130                 if (!cmp)
1131                         return k;
1132
1133                 n = n * 2 + (cmp < 0);
1134         } while (n < t->size);
1135
1136         inorder = __eytzinger1_to_inorder(n >> 1, t->size - 1, t->extra);
1137
1138         /*
1139          * n would have been the node we recursed to - the low bit tells us if
1140          * we recursed left or recursed right.
1141          */
1142         if (likely(!(n & 1))) {
1143                 --inorder;
1144                 if (unlikely(!inorder))
1145                         return btree_bkey_first(b, t);
1146
1147                 f = &base->f[eytzinger1_prev(n >> 1, t->size - 1)];
1148         }
1149
1150         return cacheline_to_bkey(b, t, inorder, f->key_offset);
1151 }
1152
1153 static __always_inline __flatten
1154 struct bkey_packed *__bch2_bset_search(struct btree *b,
1155                                 struct bset_tree *t,
1156                                 struct bpos *search,
1157                                 const struct bkey_packed *lossy_packed_search)
1158 {
1159
1160         /*
1161          * First, we search for a cacheline, then lastly we do a linear search
1162          * within that cacheline.
1163          *
1164          * To search for the cacheline, there's three different possibilities:
1165          *  * The set is too small to have a search tree, so we just do a linear
1166          *    search over the whole set.
1167          *  * The set is the one we're currently inserting into; keeping a full
1168          *    auxiliary search tree up to date would be too expensive, so we
1169          *    use a much simpler lookup table to do a binary search -
1170          *    bset_search_write_set().
1171          *  * Or we use the auxiliary search tree we constructed earlier -
1172          *    bset_search_tree()
1173          */
1174
1175         switch (bset_aux_tree_type(t)) {
1176         case BSET_NO_AUX_TREE:
1177                 return btree_bkey_first(b, t);
1178         case BSET_RW_AUX_TREE:
1179                 return bset_search_write_set(b, t, search);
1180         case BSET_RO_AUX_TREE:
1181                 return bset_search_tree(b, t, search, lossy_packed_search);
1182         default:
1183                 BUG();
1184         }
1185 }
1186
1187 static __always_inline __flatten
1188 struct bkey_packed *bch2_bset_search_linear(struct btree *b,
1189                                 struct bset_tree *t,
1190                                 struct bpos *search,
1191                                 struct bkey_packed *packed_search,
1192                                 const struct bkey_packed *lossy_packed_search,
1193                                 struct bkey_packed *m)
1194 {
1195         if (lossy_packed_search)
1196                 while (m != btree_bkey_last(b, t) &&
1197                        bkey_iter_cmp_p_or_unp(b, m,
1198                                         lossy_packed_search, search) < 0)
1199                         m = bkey_p_next(m);
1200
1201         if (!packed_search)
1202                 while (m != btree_bkey_last(b, t) &&
1203                        bkey_iter_pos_cmp(b, m, search) < 0)
1204                         m = bkey_p_next(m);
1205
1206         if (static_branch_unlikely(&bch2_debug_check_bset_lookups)) {
1207                 struct bkey_packed *prev = bch2_bkey_prev_all(b, t, m);
1208
1209                 BUG_ON(prev &&
1210                        bkey_iter_cmp_p_or_unp(b, prev,
1211                                         packed_search, search) >= 0);
1212         }
1213
1214         return m;
1215 }
1216
1217 /* Btree node iterator */
1218
1219 static inline void __bch2_btree_node_iter_push(struct btree_node_iter *iter,
1220                               struct btree *b,
1221                               const struct bkey_packed *k,
1222                               const struct bkey_packed *end)
1223 {
1224         if (k != end) {
1225                 struct btree_node_iter_set *pos;
1226
1227                 btree_node_iter_for_each(iter, pos)
1228                         ;
1229
1230                 BUG_ON(pos >= iter->data + ARRAY_SIZE(iter->data));
1231                 *pos = (struct btree_node_iter_set) {
1232                         __btree_node_key_to_offset(b, k),
1233                         __btree_node_key_to_offset(b, end)
1234                 };
1235         }
1236 }
1237
1238 void bch2_btree_node_iter_push(struct btree_node_iter *iter,
1239                                struct btree *b,
1240                                const struct bkey_packed *k,
1241                                const struct bkey_packed *end)
1242 {
1243         __bch2_btree_node_iter_push(iter, b, k, end);
1244         bch2_btree_node_iter_sort(iter, b);
1245 }
1246
1247 noinline __flatten __cold
1248 static void btree_node_iter_init_pack_failed(struct btree_node_iter *iter,
1249                               struct btree *b, struct bpos *search)
1250 {
1251         struct bkey_packed *k;
1252
1253         trace_bkey_pack_pos_fail(search);
1254
1255         bch2_btree_node_iter_init_from_start(iter, b);
1256
1257         while ((k = bch2_btree_node_iter_peek(iter, b)) &&
1258                bkey_iter_pos_cmp(b, k, search) < 0)
1259                 bch2_btree_node_iter_advance(iter, b);
1260 }
1261
1262 /**
1263  * bch2_btree_node_iter_init - initialize a btree node iterator, starting from a
1264  * given position
1265  *
1266  * @iter:       iterator to initialize
1267  * @b:          btree node to search
1268  * @search:     search key
1269  *
1270  * Main entry point to the lookup code for individual btree nodes:
1271  *
1272  * NOTE:
1273  *
1274  * When you don't filter out deleted keys, btree nodes _do_ contain duplicate
1275  * keys. This doesn't matter for most code, but it does matter for lookups.
1276  *
1277  * Some adjacent keys with a string of equal keys:
1278  *      i j k k k k l m
1279  *
1280  * If you search for k, the lookup code isn't guaranteed to return you any
1281  * specific k. The lookup code is conceptually doing a binary search and
1282  * iterating backwards is very expensive so if the pivot happens to land at the
1283  * last k that's what you'll get.
1284  *
1285  * This works out ok, but it's something to be aware of:
1286  *
1287  *  - For non extents, we guarantee that the live key comes last - see
1288  *    btree_node_iter_cmp(), keys_out_of_order(). So the duplicates you don't
1289  *    see will only be deleted keys you don't care about.
1290  *
1291  *  - For extents, deleted keys sort last (see the comment at the top of this
1292  *    file). But when you're searching for extents, you actually want the first
1293  *    key strictly greater than your search key - an extent that compares equal
1294  *    to the search key is going to have 0 sectors after the search key.
1295  *
1296  *    But this does mean that we can't just search for
1297  *    bpos_successor(start_of_range) to get the first extent that overlaps with
1298  *    the range we want - if we're unlucky and there's an extent that ends
1299  *    exactly where we searched, then there could be a deleted key at the same
1300  *    position and we'd get that when we search instead of the preceding extent
1301  *    we needed.
1302  *
1303  *    So we've got to search for start_of_range, then after the lookup iterate
1304  *    past any extents that compare equal to the position we searched for.
1305  */
1306 __flatten
1307 void bch2_btree_node_iter_init(struct btree_node_iter *iter,
1308                                struct btree *b, struct bpos *search)
1309 {
1310         struct bkey_packed p, *packed_search = NULL;
1311         struct btree_node_iter_set *pos = iter->data;
1312         struct bkey_packed *k[MAX_BSETS];
1313         unsigned i;
1314
1315         EBUG_ON(bpos_lt(*search, b->data->min_key));
1316         EBUG_ON(bpos_gt(*search, b->data->max_key));
1317         bset_aux_tree_verify(b);
1318
1319         memset(iter, 0, sizeof(*iter));
1320
1321         switch (bch2_bkey_pack_pos_lossy(&p, *search, b)) {
1322         case BKEY_PACK_POS_EXACT:
1323                 packed_search = &p;
1324                 break;
1325         case BKEY_PACK_POS_SMALLER:
1326                 packed_search = NULL;
1327                 break;
1328         case BKEY_PACK_POS_FAIL:
1329                 btree_node_iter_init_pack_failed(iter, b, search);
1330                 return;
1331         }
1332
1333         for (i = 0; i < b->nsets; i++) {
1334                 k[i] = __bch2_bset_search(b, b->set + i, search, &p);
1335                 prefetch_four_cachelines(k[i]);
1336         }
1337
1338         for (i = 0; i < b->nsets; i++) {
1339                 struct bset_tree *t = b->set + i;
1340                 struct bkey_packed *end = btree_bkey_last(b, t);
1341
1342                 k[i] = bch2_bset_search_linear(b, t, search,
1343                                                packed_search, &p, k[i]);
1344                 if (k[i] != end)
1345                         *pos++ = (struct btree_node_iter_set) {
1346                                 __btree_node_key_to_offset(b, k[i]),
1347                                 __btree_node_key_to_offset(b, end)
1348                         };
1349         }
1350
1351         bch2_btree_node_iter_sort(iter, b);
1352 }
1353
1354 void bch2_btree_node_iter_init_from_start(struct btree_node_iter *iter,
1355                                           struct btree *b)
1356 {
1357         memset(iter, 0, sizeof(*iter));
1358
1359         for_each_bset(b, t)
1360                 __bch2_btree_node_iter_push(iter, b,
1361                                            btree_bkey_first(b, t),
1362                                            btree_bkey_last(b, t));
1363         bch2_btree_node_iter_sort(iter, b);
1364 }
1365
1366 struct bkey_packed *bch2_btree_node_iter_bset_pos(struct btree_node_iter *iter,
1367                                                   struct btree *b,
1368                                                   struct bset_tree *t)
1369 {
1370         struct btree_node_iter_set *set;
1371
1372         btree_node_iter_for_each(iter, set)
1373                 if (set->end == t->end_offset)
1374                         return __btree_node_offset_to_key(b, set->k);
1375
1376         return btree_bkey_last(b, t);
1377 }
1378
1379 static inline bool btree_node_iter_sort_two(struct btree_node_iter *iter,
1380                                             struct btree *b,
1381                                             unsigned first)
1382 {
1383         bool ret;
1384
1385         if ((ret = (btree_node_iter_cmp(b,
1386                                         iter->data[first],
1387                                         iter->data[first + 1]) > 0)))
1388                 swap(iter->data[first], iter->data[first + 1]);
1389         return ret;
1390 }
1391
1392 void bch2_btree_node_iter_sort(struct btree_node_iter *iter,
1393                                struct btree *b)
1394 {
1395         /* unrolled bubble sort: */
1396
1397         if (!__btree_node_iter_set_end(iter, 2)) {
1398                 btree_node_iter_sort_two(iter, b, 0);
1399                 btree_node_iter_sort_two(iter, b, 1);
1400         }
1401
1402         if (!__btree_node_iter_set_end(iter, 1))
1403                 btree_node_iter_sort_two(iter, b, 0);
1404 }
1405
1406 void bch2_btree_node_iter_set_drop(struct btree_node_iter *iter,
1407                                    struct btree_node_iter_set *set)
1408 {
1409         struct btree_node_iter_set *last =
1410                 iter->data + ARRAY_SIZE(iter->data) - 1;
1411
1412         memmove(&set[0], &set[1], (void *) last - (void *) set);
1413         *last = (struct btree_node_iter_set) { 0, 0 };
1414 }
1415
1416 static inline void __bch2_btree_node_iter_advance(struct btree_node_iter *iter,
1417                                                   struct btree *b)
1418 {
1419         iter->data->k += __bch2_btree_node_iter_peek_all(iter, b)->u64s;
1420
1421         EBUG_ON(iter->data->k > iter->data->end);
1422
1423         if (unlikely(__btree_node_iter_set_end(iter, 0))) {
1424                 /* avoid an expensive memmove call: */
1425                 iter->data[0] = iter->data[1];
1426                 iter->data[1] = iter->data[2];
1427                 iter->data[2] = (struct btree_node_iter_set) { 0, 0 };
1428                 return;
1429         }
1430
1431         if (__btree_node_iter_set_end(iter, 1))
1432                 return;
1433
1434         if (!btree_node_iter_sort_two(iter, b, 0))
1435                 return;
1436
1437         if (__btree_node_iter_set_end(iter, 2))
1438                 return;
1439
1440         btree_node_iter_sort_two(iter, b, 1);
1441 }
1442
1443 void bch2_btree_node_iter_advance(struct btree_node_iter *iter,
1444                                   struct btree *b)
1445 {
1446         if (static_branch_unlikely(&bch2_debug_check_bset_lookups)) {
1447                 __bch2_btree_node_iter_verify(iter, b);
1448                 __bch2_btree_node_iter_next_check(iter, b);
1449         }
1450
1451         __bch2_btree_node_iter_advance(iter, b);
1452 }
1453
1454 /*
1455  * Expensive:
1456  */
1457 struct bkey_packed *bch2_btree_node_iter_prev_all(struct btree_node_iter *iter,
1458                                                   struct btree *b)
1459 {
1460         struct bkey_packed *k, *prev = NULL;
1461         struct btree_node_iter_set *set;
1462         unsigned end = 0;
1463
1464         bch2_btree_node_iter_verify(iter, b);
1465
1466         for_each_bset(b, t) {
1467                 k = bch2_bkey_prev_all(b, t,
1468                         bch2_btree_node_iter_bset_pos(iter, b, t));
1469                 if (k &&
1470                     (!prev || bkey_iter_cmp(b, k, prev) > 0)) {
1471                         prev = k;
1472                         end = t->end_offset;
1473                 }
1474         }
1475
1476         if (!prev)
1477                 return NULL;
1478
1479         /*
1480          * We're manually memmoving instead of just calling sort() to ensure the
1481          * prev we picked ends up in slot 0 - sort won't necessarily put it
1482          * there because of duplicate deleted keys:
1483          */
1484         btree_node_iter_for_each(iter, set)
1485                 if (set->end == end)
1486                         goto found;
1487
1488         BUG_ON(set != &iter->data[__btree_node_iter_used(iter)]);
1489 found:
1490         BUG_ON(set >= iter->data + ARRAY_SIZE(iter->data));
1491
1492         memmove(&iter->data[1],
1493                 &iter->data[0],
1494                 (void *) set - (void *) &iter->data[0]);
1495
1496         iter->data[0].k = __btree_node_key_to_offset(b, prev);
1497         iter->data[0].end = end;
1498
1499         bch2_btree_node_iter_verify(iter, b);
1500         return prev;
1501 }
1502
1503 struct bkey_packed *bch2_btree_node_iter_prev(struct btree_node_iter *iter,
1504                                               struct btree *b)
1505 {
1506         struct bkey_packed *prev;
1507
1508         do {
1509                 prev = bch2_btree_node_iter_prev_all(iter, b);
1510         } while (prev && bkey_deleted(prev));
1511
1512         return prev;
1513 }
1514
1515 struct bkey_s_c bch2_btree_node_iter_peek_unpack(struct btree_node_iter *iter,
1516                                                  struct btree *b,
1517                                                  struct bkey *u)
1518 {
1519         struct bkey_packed *k = bch2_btree_node_iter_peek(iter, b);
1520
1521         return k ? bkey_disassemble(b, k, u) : bkey_s_c_null;
1522 }
1523
1524 /* Mergesort */
1525
1526 void bch2_btree_keys_stats(const struct btree *b, struct bset_stats *stats)
1527 {
1528         for_each_bset_c(b, t) {
1529                 enum bset_aux_tree_type type = bset_aux_tree_type(t);
1530                 size_t j;
1531
1532                 stats->sets[type].nr++;
1533                 stats->sets[type].bytes += le16_to_cpu(bset(b, t)->u64s) *
1534                         sizeof(u64);
1535
1536                 if (bset_has_ro_aux_tree(t)) {
1537                         stats->floats += t->size - 1;
1538
1539                         for (j = 1; j < t->size; j++)
1540                                 stats->failed +=
1541                                         bkey_float(b, t, j)->exponent ==
1542                                         BFLOAT_FAILED;
1543                 }
1544         }
1545 }
1546
1547 void bch2_bfloat_to_text(struct printbuf *out, struct btree *b,
1548                          struct bkey_packed *k)
1549 {
1550         struct bset_tree *t = bch2_bkey_to_bset(b, k);
1551         struct bkey uk;
1552         unsigned j, inorder;
1553
1554         if (!bset_has_ro_aux_tree(t))
1555                 return;
1556
1557         inorder = bkey_to_cacheline(b, t, k);
1558         if (!inorder || inorder >= t->size)
1559                 return;
1560
1561         j = __inorder_to_eytzinger1(inorder, t->size - 1, t->extra);
1562         if (k != tree_to_bkey(b, t, j))
1563                 return;
1564
1565         switch (bkey_float(b, t, j)->exponent) {
1566         case BFLOAT_FAILED:
1567                 uk = bkey_unpack_key(b, k);
1568                 prt_printf(out,
1569                        "    failed unpacked at depth %u\n"
1570                        "\t",
1571                        ilog2(j));
1572                 bch2_bpos_to_text(out, uk.p);
1573                 prt_printf(out, "\n");
1574                 break;
1575         }
1576 }