git.sesse.net Git - bcachefs-tools-debian/blob - libbcachefs/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 "util.h"
  14
  15 #include <asm/unaligned.h>
  16 #include <linux/console.h>
  17 #include <linux/random.h>
  18 #include <linux/prefetch.h>
  19
  20 /* hack.. */
  21 #include "alloc_types.h"
  22 #include <trace/events/bcachefs.h>
  23
  24 static inline void __bch2_btree_node_iter_advance(struct btree_node_iter *,
  25                                                   struct btree *);
  26
  27 static inline unsigned __btree_node_iter_used(struct btree_node_iter *iter)
  28 {
  29         unsigned n = ARRAY_SIZE(iter->data);
  30
  31         while (n && __btree_node_iter_set_end(iter, n - 1))
  32                 --n;
  33
  34         return n;
  35 }
  36
  37 struct bset_tree *bch2_bkey_to_bset(struct btree *b, struct bkey_packed *k)
  38 {
  39         unsigned offset = __btree_node_key_to_offset(b, k);
  40         struct bset_tree *t;
  41
  42         for_each_bset(b, t)
  43                 if (offset <= t->end_offset) {
  44                         EBUG_ON(offset < btree_bkey_first_offset(t));
  45                         return t;
  46                 }
  47
  48         BUG();
  49 }
  50
  51 /*
  52  * There are never duplicate live keys in the btree - but including keys that
  53  * have been flagged as deleted (and will be cleaned up later) we _will_ see
  54  * duplicates.
  55  *
  56  * Thus the sort order is: usual key comparison first, but for keys that compare
  57  * equal the deleted key(s) come first, and the (at most one) live version comes
  58  * last.
  59  *
  60  * The main reason for this is insertion: to handle overwrites, we first iterate
  61  * over keys that compare equal to our insert key, and then insert immediately
  62  * prior to the first key greater than the key we're inserting - our insert
  63  * position will be after all keys that compare equal to our insert key, which
  64  * by the time we actually do the insert will all be deleted.
  65  */
  66
  67 void bch2_dump_bset(struct bch_fs *c, struct btree *b,
  68                     struct bset *i, unsigned set)
  69 {
  70         struct bkey_packed *_k, *_n;
  71         struct bkey uk, n;
  72         struct bkey_s_c k;
  73         char buf[200];
  74
  75         if (!i->u64s)
  76                 return;
  77
  78         for (_k = i->start;
  79              _k < vstruct_last(i);
  80              _k = _n) {
  81                 _n = bkey_next_skip_noops(_k, vstruct_last(i));
  82
  83                 k = bkey_disassemble(b, _k, &uk);
  84                 if (c)
  85                         bch2_bkey_val_to_text(&PBUF(buf), c, k);
  86                 else
  87                         bch2_bkey_to_text(&PBUF(buf), k.k);
  88                 printk(KERN_ERR "block %u key %5zu: %s\n", set,
  89                        _k->_data - i->_data, buf);
  90
  91                 if (_n == vstruct_last(i))
  92                         continue;
  93
  94                 n = bkey_unpack_key(b, _n);
  95
  96                 if (bkey_cmp(bkey_start_pos(&n), k.k->p) < 0) {
  97                         printk(KERN_ERR "Key skipped backwards\n");
  98                         continue;
  99                 }
 100
 101                 if (!bkey_deleted(k.k) &&
 102                     !bkey_cmp(n.p, k.k->p))
 103                         printk(KERN_ERR "Duplicate keys\n");
 104         }
 105 }
 106
 107 void bch2_dump_btree_node(struct bch_fs *c, struct btree *b)
 108 {
 109         struct bset_tree *t;
 110
 111         console_lock();
 112         for_each_bset(b, t)
 113                 bch2_dump_bset(c, b, bset(b, t), t - b->set);
 114         console_unlock();
 115 }
 116
 117 void bch2_dump_btree_node_iter(struct btree *b,
 118                               struct btree_node_iter *iter)
 119 {
 120         struct btree_node_iter_set *set;
 121
 122         printk(KERN_ERR "btree node iter with %u/%u sets:\n",
 123                __btree_node_iter_used(iter), b->nsets);
 124
 125         btree_node_iter_for_each(iter, set) {
 126                 struct bkey_packed *k = __btree_node_offset_to_key(b, set->k);
 127                 struct bset_tree *t = bch2_bkey_to_bset(b, k);
 128                 struct bkey uk = bkey_unpack_key(b, k);
 129                 char buf[100];
 130
 131                 bch2_bkey_to_text(&PBUF(buf), &uk);
 132                 printk(KERN_ERR "set %zu key %u: %s\n",
 133                        t - b->set, set->k, buf);
 134         }
 135 }
 136
 137 #ifdef CONFIG_BCACHEFS_DEBUG
 138
 139 void __bch2_verify_btree_nr_keys(struct btree *b)
 140 {
 141         struct bset_tree *t;
 142         struct bkey_packed *k;
 143         struct btree_nr_keys nr = { 0 };
 144
 145         for_each_bset(b, t)
 146                 bset_tree_for_each_key(b, t, k)
 147                         if (!bkey_deleted(k))
 148                                 btree_keys_account_key_add(&nr, t - b->set, k);
 149
 150         BUG_ON(memcmp(&nr, &b->nr, sizeof(nr)));
 151 }
 152
 153 static void bch2_btree_node_iter_next_check(struct btree_node_iter *_iter,
 154                                             struct btree *b)
 155 {
 156         struct btree_node_iter iter = *_iter;
 157         const struct bkey_packed *k, *n;
 158
 159         k = bch2_btree_node_iter_peek_all(&iter, b);
 160         __bch2_btree_node_iter_advance(&iter, b);
 161         n = bch2_btree_node_iter_peek_all(&iter, b);
 162
 163         bkey_unpack_key(b, k);
 164
 165         if (n &&
 166             bkey_iter_cmp(b, k, n) > 0) {
 167                 struct btree_node_iter_set *set;
 168                 struct bkey ku = bkey_unpack_key(b, k);
 169                 struct bkey nu = bkey_unpack_key(b, n);
 170                 char buf1[80], buf2[80];
 171
 172                 bch2_dump_btree_node(NULL, b);
 173                 bch2_bkey_to_text(&PBUF(buf1), &ku);
 174                 bch2_bkey_to_text(&PBUF(buf2), &nu);
 175                 printk(KERN_ERR "out of order/overlapping:\n%s\n%s\n",
 176                        buf1, buf2);
 177                 printk(KERN_ERR "iter was:");
 178
 179                 btree_node_iter_for_each(_iter, set) {
 180                         struct bkey_packed *k = __btree_node_offset_to_key(b, set->k);
 181                         struct bset_tree *t = bch2_bkey_to_bset(b, k);
 182                         printk(" [%zi %zi]", t - b->set,
 183                                k->_data - bset(b, t)->_data);
 184                 }
 185                 panic("\n");
 186         }
 187 }
 188
 189 void bch2_btree_node_iter_verify(struct btree_node_iter *iter,
 190                                  struct btree *b)
 191 {
 192         struct btree_node_iter_set *set, *s2;
 193         struct bkey_packed *k, *p;
 194         struct bset_tree *t;
 195
 196         if (bch2_btree_node_iter_end(iter))
 197                 return;
 198
 199         /* Verify no duplicates: */
 200         btree_node_iter_for_each(iter, set)
 201                 btree_node_iter_for_each(iter, s2)
 202                         BUG_ON(set != s2 && set->end == s2->end);
 203
 204         /* Verify that set->end is correct: */
 205         btree_node_iter_for_each(iter, set) {
 206                 for_each_bset(b, t)
 207                         if (set->end == t->end_offset)
 208                                 goto found;
 209                 BUG();
 210 found:
 211                 BUG_ON(set->k < btree_bkey_first_offset(t) ||
 212                        set->k >= t->end_offset);
 213         }
 214
 215         /* Verify iterator is sorted: */
 216         btree_node_iter_for_each(iter, set)
 217                 BUG_ON(set != iter->data &&
 218                        btree_node_iter_cmp(b, set[-1], set[0]) > 0);
 219
 220         k = bch2_btree_node_iter_peek_all(iter, b);
 221
 222         for_each_bset(b, t) {
 223                 if (iter->data[0].end == t->end_offset)
 224                         continue;
 225
 226                 p = bch2_bkey_prev_all(b, t,
 227                         bch2_btree_node_iter_bset_pos(iter, b, t));
 228
 229                 BUG_ON(p && bkey_iter_cmp(b, k, p) < 0);
 230         }
 231 }
 232
 233 void bch2_verify_insert_pos(struct btree *b, struct bkey_packed *where,
 234                             struct bkey_packed *insert, unsigned clobber_u64s)
 235 {
 236         struct bset_tree *t = bch2_bkey_to_bset(b, where);
 237         struct bkey_packed *prev = bch2_bkey_prev_all(b, t, where);
 238         struct bkey_packed *next = (void *) (where->_data + clobber_u64s);
 239 #if 0
 240         BUG_ON(prev &&
 241                bkey_iter_cmp(b, prev, insert) > 0);
 242 #else
 243         if (prev &&
 244             bkey_iter_cmp(b, prev, insert) > 0) {
 245                 struct bkey k1 = bkey_unpack_key(b, prev);
 246                 struct bkey k2 = bkey_unpack_key(b, insert);
 247                 char buf1[100];
 248                 char buf2[100];
 249
 250                 bch2_dump_btree_node(NULL, b);
 251                 bch2_bkey_to_text(&PBUF(buf1), &k1);
 252                 bch2_bkey_to_text(&PBUF(buf2), &k2);
 253
 254                 panic("prev > insert:\n"
 255                       "prev    key %s\n"
 256                       "insert  key %s\n",
 257                       buf1, buf2);
 258         }
 259 #endif
 260 #if 0
 261         BUG_ON(next != btree_bkey_last(b, t) &&
 262                bkey_iter_cmp(b, insert, next) > 0);
 263 #else
 264         if (next != btree_bkey_last(b, t) &&
 265             bkey_iter_cmp(b, insert, next) > 0) {
 266                 struct bkey k1 = bkey_unpack_key(b, insert);
 267                 struct bkey k2 = bkey_unpack_key(b, next);
 268                 char buf1[100];
 269                 char buf2[100];
 270
 271                 bch2_dump_btree_node(NULL, b);
 272                 bch2_bkey_to_text(&PBUF(buf1), &k1);
 273                 bch2_bkey_to_text(&PBUF(buf2), &k2);
 274
 275                 panic("insert > next:\n"
 276                       "insert  key %s\n"
 277                       "next    key %s\n",
 278                       buf1, buf2);
 279         }
 280 #endif
 281 }
 282
 283 #else
 284
 285 static inline void bch2_btree_node_iter_next_check(struct btree_node_iter *iter,
 286                                                    struct btree *b) {}
 287
 288 #endif
 289
 290 /* Auxiliary search trees */
 291
 292 #define BFLOAT_FAILED_UNPACKED  U8_MAX
 293 #define BFLOAT_FAILED           U8_MAX
 294
 295 struct bkey_float {
 296         u8              exponent;
 297         u8              key_offset;
 298         u16             mantissa;
 299 };
 300 #define BKEY_MANTISSA_BITS      16
 301
 302 static unsigned bkey_float_byte_offset(unsigned idx)
 303 {
 304         return idx * sizeof(struct bkey_float);
 305 }
 306
 307 struct ro_aux_tree {
 308         struct bkey_float       f[0];
 309 };
 310
 311 struct rw_aux_tree {
 312         u16             offset;
 313         struct bpos     k;
 314 };
 315
 316 static unsigned bset_aux_tree_buf_end(const struct bset_tree *t)
 317 {
 318         BUG_ON(t->aux_data_offset == U16_MAX);
 319
 320         switch (bset_aux_tree_type(t)) {
 321         case BSET_NO_AUX_TREE:
 322                 return t->aux_data_offset;
 323         case BSET_RO_AUX_TREE:
 324                 return t->aux_data_offset +
 325                         DIV_ROUND_UP(t->size * sizeof(struct bkey_float) +
 326                                      t->size * sizeof(u8), 8);
 327         case BSET_RW_AUX_TREE:
 328                 return t->aux_data_offset +
 329                         DIV_ROUND_UP(sizeof(struct rw_aux_tree) * t->size, 8);
 330         default:
 331                 BUG();
 332         }
 333 }
 334
 335 static unsigned bset_aux_tree_buf_start(const struct btree *b,
 336                                         const struct bset_tree *t)
 337 {
 338         return t == b->set
 339                 ? DIV_ROUND_UP(b->unpack_fn_len, 8)
 340                 : bset_aux_tree_buf_end(t - 1);
 341 }
 342
 343 static void *__aux_tree_base(const struct btree *b,
 344                              const struct bset_tree *t)
 345 {
 346         return b->aux_data + t->aux_data_offset * 8;
 347 }
 348
 349 static struct ro_aux_tree *ro_aux_tree_base(const struct btree *b,
 350                                             const struct bset_tree *t)
 351 {
 352         EBUG_ON(bset_aux_tree_type(t) != BSET_RO_AUX_TREE);
 353
 354         return __aux_tree_base(b, t);
 355 }
 356
 357 static u8 *ro_aux_tree_prev(const struct btree *b,
 358                             const struct bset_tree *t)
 359 {
 360         EBUG_ON(bset_aux_tree_type(t) != BSET_RO_AUX_TREE);
 361
 362         return __aux_tree_base(b, t) + bkey_float_byte_offset(t->size);
 363 }
 364
 365 static struct bkey_float *bkey_float(const struct btree *b,
 366                                      const struct bset_tree *t,
 367                                      unsigned idx)
 368 {
 369         return ro_aux_tree_base(b, t)->f + idx;
 370 }
 371
 372 static void bset_aux_tree_verify(const struct btree *b)
 373 {
 374 #ifdef CONFIG_BCACHEFS_DEBUG
 375         const struct bset_tree *t;
 376
 377         for_each_bset(b, t) {
 378                 if (t->aux_data_offset == U16_MAX)
 379                         continue;
 380
 381                 BUG_ON(t != b->set &&
 382                        t[-1].aux_data_offset == U16_MAX);
 383
 384                 BUG_ON(t->aux_data_offset < bset_aux_tree_buf_start(b, t));
 385                 BUG_ON(t->aux_data_offset > btree_aux_data_u64s(b));
 386                 BUG_ON(bset_aux_tree_buf_end(t) > btree_aux_data_u64s(b));
 387         }
 388 #endif
 389 }
 390
 391 void bch2_btree_keys_init(struct btree *b)
 392 {
 393         unsigned i;
 394
 395         b->nsets                = 0;
 396         memset(&b->nr, 0, sizeof(b->nr));
 397
 398         for (i = 0; i < MAX_BSETS; i++)
 399                 b->set[i].data_offset = U16_MAX;
 400
 401         bch2_bset_set_no_aux_tree(b, b->set);
 402 }
 403
 404 /* Binary tree stuff for auxiliary search trees */
 405
 406 /*
 407  * Cacheline/offset <-> bkey pointer arithmetic:
 408  *
 409  * t->tree is a binary search tree in an array; each node corresponds to a key
 410  * in one cacheline in t->set (BSET_CACHELINE bytes).
 411  *
 412  * This means we don't have to store the full index of the key that a node in
 413  * the binary tree points to; eytzinger1_to_inorder() gives us the cacheline, and
 414  * then bkey_float->m gives us the offset within that cacheline, in units of 8
 415  * bytes.
 416  *
 417  * cacheline_to_bkey() and friends abstract out all the pointer arithmetic to
 418  * make this work.
 419  *
 420  * To construct the bfloat for an arbitrary key we need to know what the key
 421  * immediately preceding it is: we have to check if the two keys differ in the
 422  * bits we're going to store in bkey_float->mantissa. t->prev[j] stores the size
 423  * of the previous key so we can walk backwards to it from t->tree[j]'s key.
 424  */
 425
 426 static inline void *bset_cacheline(const struct btree *b,
 427                                    const struct bset_tree *t,
 428                                    unsigned cacheline)
 429 {
 430         return (void *) round_down((unsigned long) btree_bkey_first(b, t),
 431                                    L1_CACHE_BYTES) +
 432                 cacheline * BSET_CACHELINE;
 433 }
 434
 435 static struct bkey_packed *cacheline_to_bkey(const struct btree *b,
 436                                              const struct bset_tree *t,
 437                                              unsigned cacheline,
 438                                              unsigned offset)
 439 {
 440         return bset_cacheline(b, t, cacheline) + offset * 8;
 441 }
 442
 443 static unsigned bkey_to_cacheline(const struct btree *b,
 444                                   const struct bset_tree *t,
 445                                   const struct bkey_packed *k)
 446 {
 447         return ((void *) k - bset_cacheline(b, t, 0)) / BSET_CACHELINE;
 448 }
 449
 450 static ssize_t __bkey_to_cacheline_offset(const struct btree *b,
 451                                           const struct bset_tree *t,
 452                                           unsigned cacheline,
 453                                           const struct bkey_packed *k)
 454 {
 455         return (u64 *) k - (u64 *) bset_cacheline(b, t, cacheline);
 456 }
 457
 458 static unsigned bkey_to_cacheline_offset(const struct btree *b,
 459                                          const struct bset_tree *t,
 460                                          unsigned cacheline,
 461                                          const struct bkey_packed *k)
 462 {
 463         size_t m = __bkey_to_cacheline_offset(b, t, cacheline, k);
 464
 465         EBUG_ON(m > U8_MAX);
 466         return m;
 467 }
 468
 469 static inline struct bkey_packed *tree_to_bkey(const struct btree *b,
 470                                                const struct bset_tree *t,
 471                                                unsigned j)
 472 {
 473         return cacheline_to_bkey(b, t,
 474                         __eytzinger1_to_inorder(j, t->size, t->extra),
 475                         bkey_float(b, t, j)->key_offset);
 476 }
 477
 478 static struct bkey_packed *tree_to_prev_bkey(const struct btree *b,
 479                                              const struct bset_tree *t,
 480                                              unsigned j)
 481 {
 482         unsigned prev_u64s = ro_aux_tree_prev(b, t)[j];
 483
 484         return (void *) (tree_to_bkey(b, t, j)->_data - prev_u64s);
 485 }
 486
 487 static struct rw_aux_tree *rw_aux_tree(const struct btree *b,
 488                                        const struct bset_tree *t)
 489 {
 490         EBUG_ON(bset_aux_tree_type(t) != BSET_RW_AUX_TREE);
 491
 492         return __aux_tree_base(b, t);
 493 }
 494
 495 /*
 496  * For the write set - the one we're currently inserting keys into - we don't
 497  * maintain a full search tree, we just keep a simple lookup table in t->prev.
 498  */
 499 static struct bkey_packed *rw_aux_to_bkey(const struct btree *b,
 500                                           struct bset_tree *t,
 501                                           unsigned j)
 502 {
 503         return __btree_node_offset_to_key(b, rw_aux_tree(b, t)[j].offset);
 504 }
 505
 506 static void rw_aux_tree_set(const struct btree *b, struct bset_tree *t,
 507                             unsigned j, struct bkey_packed *k)
 508 {
 509         EBUG_ON(k >= btree_bkey_last(b, t));
 510
 511         rw_aux_tree(b, t)[j] = (struct rw_aux_tree) {
 512                 .offset = __btree_node_key_to_offset(b, k),
 513                 .k      = bkey_unpack_pos(b, k),
 514         };
 515 }
 516
 517 static void bch2_bset_verify_rw_aux_tree(struct btree *b,
 518                                         struct bset_tree *t)
 519 {
 520         struct bkey_packed *k = btree_bkey_first(b, t);
 521         unsigned j = 0;
 522
 523         if (!bch2_expensive_debug_checks)
 524                 return;
 525
 526         BUG_ON(bset_has_ro_aux_tree(t));
 527
 528         if (!bset_has_rw_aux_tree(t))
 529                 return;
 530
 531         BUG_ON(t->size < 1);
 532         BUG_ON(rw_aux_to_bkey(b, t, j) != k);
 533
 534         goto start;
 535         while (1) {
 536                 if (rw_aux_to_bkey(b, t, j) == k) {
 537                         BUG_ON(bkey_cmp(rw_aux_tree(b, t)[j].k,
 538                                         bkey_unpack_pos(b, k)));
 539 start:
 540                         if (++j == t->size)
 541                                 break;
 542
 543                         BUG_ON(rw_aux_tree(b, t)[j].offset <=
 544                                rw_aux_tree(b, t)[j - 1].offset);
 545                 }
 546
 547                 k = bkey_next_skip_noops(k, btree_bkey_last(b, t));
 548                 BUG_ON(k >= btree_bkey_last(b, t));
 549         }
 550 }
 551
 552 /* returns idx of first entry >= offset: */
 553 static unsigned rw_aux_tree_bsearch(struct btree *b,
 554                                     struct bset_tree *t,
 555                                     unsigned offset)
 556 {
 557         unsigned bset_offs = offset - btree_bkey_first_offset(t);
 558         unsigned bset_u64s = t->end_offset - btree_bkey_first_offset(t);
 559         unsigned idx = bset_u64s ? bset_offs * t->size / bset_u64s : 0;
 560
 561         EBUG_ON(bset_aux_tree_type(t) != BSET_RW_AUX_TREE);
 562         EBUG_ON(!t->size);
 563         EBUG_ON(idx > t->size);
 564
 565         while (idx < t->size &&
 566                rw_aux_tree(b, t)[idx].offset < offset)
 567                 idx++;
 568
 569         while (idx &&
 570                rw_aux_tree(b, t)[idx - 1].offset >= offset)
 571                 idx--;
 572
 573         EBUG_ON(idx < t->size &&
 574                 rw_aux_tree(b, t)[idx].offset < offset);
 575         EBUG_ON(idx && rw_aux_tree(b, t)[idx - 1].offset >= offset);
 576         EBUG_ON(idx + 1 < t->size &&
 577                 rw_aux_tree(b, t)[idx].offset ==
 578                 rw_aux_tree(b, t)[idx + 1].offset);
 579
 580         return idx;
 581 }
 582
 583 static inline unsigned bkey_mantissa(const struct bkey_packed *k,
 584                                      const struct bkey_float *f,
 585                                      unsigned idx)
 586 {
 587         u64 v;
 588
 589         EBUG_ON(!bkey_packed(k));
 590
 591         v = get_unaligned((u64 *) (((u8 *) k->_data) + (f->exponent >> 3)));
 592
 593         /*
 594          * In little endian, we're shifting off low bits (and then the bits we
 595          * want are at the low end), in big endian we're shifting off high bits
 596          * (and then the bits we want are at the high end, so we shift them
 597          * back down):
 598          */
 599 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 600         v >>= f->exponent & 7;
 601 #else
 602         v >>= 64 - (f->exponent & 7) - BKEY_MANTISSA_BITS;
 603 #endif
 604         return (u16) v;
 605 }
 606
 607 __always_inline
 608 static inline void __make_bfloat(struct btree *b, struct bset_tree *t,
 609                                  unsigned j,
 610                                  struct bkey_packed *min_key,
 611                                  struct bkey_packed *max_key)
 612 {
 613         struct bkey_float *f = bkey_float(b, t, j);
 614         struct bkey_packed *m = tree_to_bkey(b, t, j);
 615         struct bkey_packed *l = is_power_of_2(j)
 616                 ? min_key
 617                 : tree_to_prev_bkey(b, t, j >> ffs(j));
 618         struct bkey_packed *r = is_power_of_2(j + 1)
 619                 ? max_key
 620                 : tree_to_bkey(b, t, j >> (ffz(j) + 1));
 621         unsigned mantissa;
 622         int shift, exponent, high_bit;
 623
 624         /*
 625          * for failed bfloats, the lookup code falls back to comparing against
 626          * the original key.
 627          */
 628
 629         if (!bkey_packed(l) || !bkey_packed(r) || !bkey_packed(m) ||
 630             !b->nr_key_bits) {
 631                 f->exponent = BFLOAT_FAILED_UNPACKED;
 632                 return;
 633         }
 634
 635         /*
 636          * The greatest differing bit of l and r is the first bit we must
 637          * include in the bfloat mantissa we're creating in order to do
 638          * comparisons - that bit always becomes the high bit of
 639          * bfloat->mantissa, and thus the exponent we're calculating here is
 640          * the position of what will become the low bit in bfloat->mantissa:
 641          *
 642          * Note that this may be negative - we may be running off the low end
 643          * of the key: we handle this later:
 644          */
 645         high_bit = max(bch2_bkey_greatest_differing_bit(b, l, r),
 646                        min_t(unsigned, BKEY_MANTISSA_BITS, b->nr_key_bits) - 1);
 647         exponent = high_bit - (BKEY_MANTISSA_BITS - 1);
 648
 649         /*
 650          * Then we calculate the actual shift value, from the start of the key
 651          * (k->_data), to get the key bits starting at exponent:
 652          */
 653 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 654         shift = (int) (b->format.key_u64s * 64 - b->nr_key_bits) + exponent;
 655
 656         EBUG_ON(shift + BKEY_MANTISSA_BITS > b->format.key_u64s * 64);
 657 #else
 658         shift = high_bit_offset +
 659                 b->nr_key_bits -
 660                 exponent -
 661                 BKEY_MANTISSA_BITS;
 662
 663         EBUG_ON(shift < KEY_PACKED_BITS_START);
 664 #endif
 665         EBUG_ON(shift < 0 || shift >= BFLOAT_FAILED);
 666
 667         f->exponent = shift;
 668         mantissa = bkey_mantissa(m, f, j);
 669
 670         /*
 671          * If we've got garbage bits, set them to all 1s - it's legal for the
 672          * bfloat to compare larger than the original key, but not smaller:
 673          */
 674         if (exponent < 0)
 675                 mantissa |= ~(~0U << -exponent);
 676
 677         f->mantissa = mantissa;
 678 }
 679
 680 static void make_bfloat(struct btree *b, struct bset_tree *t,
 681                         unsigned j,
 682                         struct bkey_packed *min_key,
 683                         struct bkey_packed *max_key)
 684 {
 685         struct bkey_i *k;
 686
 687         if (is_power_of_2(j) &&
 688             !min_key->u64s) {
 689                 k = (void *) min_key;
 690                 bkey_init(&k->k);
 691                 k->k.p = b->data->min_key;
 692         }
 693
 694         if (is_power_of_2(j + 1) &&
 695             !max_key->u64s) {
 696                 k = (void *) max_key;
 697                 bkey_init(&k->k);
 698                 k->k.p = t->max_key;
 699         }
 700
 701         __make_bfloat(b, t, j, min_key, max_key);
 702 }
 703
 704 /* bytes remaining - only valid for last bset: */
 705 static unsigned __bset_tree_capacity(const struct btree *b, const struct bset_tree *t)
 706 {
 707         bset_aux_tree_verify(b);
 708
 709         return btree_aux_data_bytes(b) - t->aux_data_offset * sizeof(u64);
 710 }
 711
 712 static unsigned bset_ro_tree_capacity(const struct btree *b, const struct bset_tree *t)
 713 {
 714         return __bset_tree_capacity(b, t) /
 715                 (sizeof(struct bkey_float) + sizeof(u8));
 716 }
 717
 718 static unsigned bset_rw_tree_capacity(const struct btree *b, const struct bset_tree *t)
 719 {
 720         return __bset_tree_capacity(b, t) / sizeof(struct rw_aux_tree);
 721 }
 722
 723 static noinline void __build_rw_aux_tree(struct btree *b, struct bset_tree *t)
 724 {
 725         struct bkey_packed *k;
 726
 727         t->size = 1;
 728         t->extra = BSET_RW_AUX_TREE_VAL;
 729         rw_aux_tree(b, t)[0].offset =
 730                 __btree_node_key_to_offset(b, btree_bkey_first(b, t));
 731
 732         bset_tree_for_each_key(b, t, k) {
 733                 if (t->size == bset_rw_tree_capacity(b, t))
 734                         break;
 735
 736                 if ((void *) k - (void *) rw_aux_to_bkey(b, t, t->size - 1) >
 737                     L1_CACHE_BYTES)
 738                         rw_aux_tree_set(b, t, t->size++, k);
 739         }
 740 }
 741
 742 static noinline void __build_ro_aux_tree(struct btree *b, struct bset_tree *t)
 743 {
 744         struct bkey_packed *prev = NULL, *k = btree_bkey_first(b, t);
 745         struct bkey_i min_key, max_key;
 746         unsigned j, cacheline = 1;
 747
 748         t->size = min(bkey_to_cacheline(b, t, btree_bkey_last(b, t)),
 749                       bset_ro_tree_capacity(b, t));
 750 retry:
 751         if (t->size < 2) {
 752                 t->size = 0;
 753                 t->extra = BSET_NO_AUX_TREE_VAL;
 754                 return;
 755         }
 756
 757         t->extra = (t->size - rounddown_pow_of_two(t->size - 1)) << 1;
 758
 759         /* First we figure out where the first key in each cacheline is */
 760         eytzinger1_for_each(j, t->size) {
 761                 while (bkey_to_cacheline(b, t, k) < cacheline)
 762                         prev = k, k = bkey_next_skip_noops(k, btree_bkey_last(b, t));
 763
 764                 if (k >= btree_bkey_last(b, t)) {
 765                         /* XXX: this path sucks */
 766                         t->size--;
 767                         goto retry;
 768                 }
 769
 770                 ro_aux_tree_prev(b, t)[j] = prev->u64s;
 771                 bkey_float(b, t, j)->key_offset =
 772                         bkey_to_cacheline_offset(b, t, cacheline++, k);
 773
 774                 EBUG_ON(tree_to_prev_bkey(b, t, j) != prev);
 775                 EBUG_ON(tree_to_bkey(b, t, j) != k);
 776         }
 777
 778         while (k != btree_bkey_last(b, t))
 779                 prev = k, k = bkey_next_skip_noops(k, btree_bkey_last(b, t));
 780
 781         t->max_key = bkey_unpack_pos(b, prev);
 782
 783         bkey_init(&min_key.k);
 784         min_key.k.p = b->data->min_key;
 785         bkey_init(&max_key.k);
 786         max_key.k.p = t->max_key;
 787
 788         /* Then we build the tree */
 789         eytzinger1_for_each(j, t->size)
 790                 __make_bfloat(b, t, j,
 791                               bkey_to_packed(&min_key),
 792                               bkey_to_packed(&max_key));
 793 }
 794
 795 static void bset_alloc_tree(struct btree *b, struct bset_tree *t)
 796 {
 797         struct bset_tree *i;
 798
 799         for (i = b->set; i != t; i++)
 800                 BUG_ON(bset_has_rw_aux_tree(i));
 801
 802         bch2_bset_set_no_aux_tree(b, t);
 803
 804         /* round up to next cacheline: */
 805         t->aux_data_offset = round_up(bset_aux_tree_buf_start(b, t),
 806                                       SMP_CACHE_BYTES / sizeof(u64));
 807
 808         bset_aux_tree_verify(b);
 809 }
 810
 811 void bch2_bset_build_aux_tree(struct btree *b, struct bset_tree *t,
 812                              bool writeable)
 813 {
 814         if (writeable
 815             ? bset_has_rw_aux_tree(t)
 816             : bset_has_ro_aux_tree(t))
 817                 return;
 818
 819         bset_alloc_tree(b, t);
 820
 821         if (!__bset_tree_capacity(b, t))
 822                 return;
 823
 824         if (writeable)
 825                 __build_rw_aux_tree(b, t);
 826         else
 827                 __build_ro_aux_tree(b, t);
 828
 829         bset_aux_tree_verify(b);
 830 }
 831
 832 void bch2_bset_init_first(struct btree *b, struct bset *i)
 833 {
 834         struct bset_tree *t;
 835
 836         BUG_ON(b->nsets);
 837
 838         memset(i, 0, sizeof(*i));
 839         get_random_bytes(&i->seq, sizeof(i->seq));
 840         SET_BSET_BIG_ENDIAN(i, CPU_BIG_ENDIAN);
 841
 842         t = &b->set[b->nsets++];
 843         set_btree_bset(b, t, i);
 844 }
 845
 846 void bch2_bset_init_next(struct bch_fs *c, struct btree *b,
 847                          struct btree_node_entry *bne)
 848 {
 849         struct bset *i = &bne->keys;
 850         struct bset_tree *t;
 851
 852         BUG_ON(bset_byte_offset(b, bne) >= btree_bytes(c));
 853         BUG_ON((void *) bne < (void *) btree_bkey_last(b, bset_tree_last(b)));
 854         BUG_ON(b->nsets >= MAX_BSETS);
 855
 856         memset(i, 0, sizeof(*i));
 857         i->seq = btree_bset_first(b)->seq;
 858         SET_BSET_BIG_ENDIAN(i, CPU_BIG_ENDIAN);
 859
 860         t = &b->set[b->nsets++];
 861         set_btree_bset(b, t, i);
 862 }
 863
 864 /*
 865  * find _some_ key in the same bset as @k that precedes @k - not necessarily the
 866  * immediate predecessor:
 867  */
 868 static struct bkey_packed *__bkey_prev(struct btree *b, struct bset_tree *t,
 869                                        struct bkey_packed *k)
 870 {
 871         struct bkey_packed *p;
 872         unsigned offset;
 873         int j;
 874
 875         EBUG_ON(k < btree_bkey_first(b, t) ||
 876                 k > btree_bkey_last(b, t));
 877
 878         if (k == btree_bkey_first(b, t))
 879                 return NULL;
 880
 881         switch (bset_aux_tree_type(t)) {
 882         case BSET_NO_AUX_TREE:
 883                 p = btree_bkey_first(b, t);
 884                 break;
 885         case BSET_RO_AUX_TREE:
 886                 j = min_t(unsigned, t->size - 1, bkey_to_cacheline(b, t, k));
 887
 888                 do {
 889                         p = j ? tree_to_bkey(b, t,
 890                                         __inorder_to_eytzinger1(j--,
 891                                                         t->size, t->extra))
 892                               : btree_bkey_first(b, t);
 893                 } while (p >= k);
 894                 break;
 895         case BSET_RW_AUX_TREE:
 896                 offset = __btree_node_key_to_offset(b, k);
 897                 j = rw_aux_tree_bsearch(b, t, offset);
 898                 p = j ? rw_aux_to_bkey(b, t, j - 1)
 899                       : btree_bkey_first(b, t);
 900                 break;
 901         }
 902
 903         return p;
 904 }
 905
 906 struct bkey_packed *bch2_bkey_prev_filter(struct btree *b,
 907                                           struct bset_tree *t,
 908                                           struct bkey_packed *k,
 909                                           unsigned min_key_type)
 910 {
 911         struct bkey_packed *p, *i, *ret = NULL, *orig_k = k;
 912
 913         while ((p = __bkey_prev(b, t, k)) && !ret) {
 914                 for (i = p; i != k; i = bkey_next_skip_noops(i, k))
 915                         if (i->type >= min_key_type)
 916                                 ret = i;
 917
 918                 k = p;
 919         }
 920
 921         if (bch2_expensive_debug_checks) {
 922                 BUG_ON(ret >= orig_k);
 923
 924                 for (i = ret
 925                         ? bkey_next_skip_noops(ret, orig_k)
 926                         : btree_bkey_first(b, t);
 927                      i != orig_k;
 928                      i = bkey_next_skip_noops(i, orig_k))
 929                         BUG_ON(i->type >= min_key_type);
 930         }
 931
 932         return ret;
 933 }
 934
 935 /* Insert */
 936
 937 static void rw_aux_tree_fix_invalidated_key(struct btree *b,
 938                                             struct bset_tree *t,
 939                                             struct bkey_packed *k)
 940 {
 941         unsigned offset = __btree_node_key_to_offset(b, k);
 942         unsigned j = rw_aux_tree_bsearch(b, t, offset);
 943
 944         if (j < t->size &&
 945             rw_aux_tree(b, t)[j].offset == offset)
 946                 rw_aux_tree_set(b, t, j, k);
 947
 948         bch2_bset_verify_rw_aux_tree(b, t);
 949 }
 950
 951 static void ro_aux_tree_fix_invalidated_key(struct btree *b,
 952                                             struct bset_tree *t,
 953                                             struct bkey_packed *k)
 954 {
 955         struct bkey_packed min_key, max_key;
 956         unsigned inorder, j;
 957
 958         EBUG_ON(bset_aux_tree_type(t) != BSET_RO_AUX_TREE);
 959
 960         /* signal to make_bfloat() that they're uninitialized: */
 961         min_key.u64s = max_key.u64s = 0;
 962
 963         if (bkey_next_skip_noops(k, btree_bkey_last(b, t)) == btree_bkey_last(b, t)) {
 964                 t->max_key = bkey_unpack_pos(b, k);
 965
 966                 for (j = 1; j < t->size; j = j * 2 + 1)
 967                         make_bfloat(b, t, j, &min_key, &max_key);
 968         }
 969
 970         inorder = bkey_to_cacheline(b, t, k);
 971
 972         if (inorder &&
 973             inorder < t->size) {
 974                 j = __inorder_to_eytzinger1(inorder, t->size, t->extra);
 975
 976                 if (k == tree_to_bkey(b, t, j)) {
 977                         /* Fix the node this key corresponds to */
 978                         make_bfloat(b, t, j, &min_key, &max_key);
 979
 980                         /* Children for which this key is the right boundary */
 981                         for (j = eytzinger1_left_child(j);
 982                              j < t->size;
 983                              j = eytzinger1_right_child(j))
 984                                 make_bfloat(b, t, j, &min_key, &max_key);
 985                 }
 986         }
 987
 988         if (inorder + 1 < t->size) {
 989                 j = __inorder_to_eytzinger1(inorder + 1, t->size, t->extra);
 990
 991                 if (k == tree_to_prev_bkey(b, t, j)) {
 992                         make_bfloat(b, t, j, &min_key, &max_key);
 993
 994                         /* Children for which this key is the left boundary */
 995                         for (j = eytzinger1_right_child(j);
 996                              j < t->size;
 997                              j = eytzinger1_left_child(j))
 998                                 make_bfloat(b, t, j, &min_key, &max_key);
 999                 }
1000         }
1001 }
1002
1003 /**
1004  * bch2_bset_fix_invalidated_key() - given an existing  key @k that has been
1005  * modified, fix any auxiliary search tree by remaking all the nodes in the
1006  * auxiliary search tree that @k corresponds to
1007  */
1008 void bch2_bset_fix_invalidated_key(struct btree *b, struct bkey_packed *k)
1009 {
1010         struct bset_tree *t = bch2_bkey_to_bset(b, k);
1011
1012         switch (bset_aux_tree_type(t)) {
1013         case BSET_NO_AUX_TREE:
1014                 break;
1015         case BSET_RO_AUX_TREE:
1016                 ro_aux_tree_fix_invalidated_key(b, t, k);
1017                 break;
1018         case BSET_RW_AUX_TREE:
1019                 rw_aux_tree_fix_invalidated_key(b, t, k);
1020                 break;
1021         }
1022 }
1023
1024 static void bch2_bset_fix_lookup_table(struct btree *b,
1025                                        struct bset_tree *t,
1026                                        struct bkey_packed *_where,
1027                                        unsigned clobber_u64s,
1028                                        unsigned new_u64s)
1029 {
1030         int shift = new_u64s - clobber_u64s;
1031         unsigned l, j, where = __btree_node_key_to_offset(b, _where);
1032
1033         EBUG_ON(bset_has_ro_aux_tree(t));
1034
1035         if (!bset_has_rw_aux_tree(t))
1036                 return;
1037
1038         /* returns first entry >= where */
1039         l = rw_aux_tree_bsearch(b, t, where);
1040
1041         if (!l) /* never delete first entry */
1042                 l++;
1043         else if (l < t->size &&
1044                  where < t->end_offset &&
1045                  rw_aux_tree(b, t)[l].offset == where)
1046                 rw_aux_tree_set(b, t, l++, _where);
1047
1048         /* l now > where */
1049
1050         for (j = l;
1051              j < t->size &&
1052              rw_aux_tree(b, t)[j].offset < where + clobber_u64s;
1053              j++)
1054                 ;
1055
1056         if (j < t->size &&
1057             rw_aux_tree(b, t)[j].offset + shift ==
1058             rw_aux_tree(b, t)[l - 1].offset)
1059                 j++;
1060
1061         memmove(&rw_aux_tree(b, t)[l],
1062                 &rw_aux_tree(b, t)[j],
1063                 (void *) &rw_aux_tree(b, t)[t->size] -
1064                 (void *) &rw_aux_tree(b, t)[j]);
1065         t->size -= j - l;
1066
1067         for (j = l; j < t->size; j++)
1068                rw_aux_tree(b, t)[j].offset += shift;
1069
1070         EBUG_ON(l < t->size &&
1071                 rw_aux_tree(b, t)[l].offset ==
1072                 rw_aux_tree(b, t)[l - 1].offset);
1073
1074         if (t->size < bset_rw_tree_capacity(b, t) &&
1075             (l < t->size
1076              ? rw_aux_tree(b, t)[l].offset
1077              : t->end_offset) -
1078             rw_aux_tree(b, t)[l - 1].offset >
1079             L1_CACHE_BYTES / sizeof(u64)) {
1080                 struct bkey_packed *start = rw_aux_to_bkey(b, t, l - 1);
1081                 struct bkey_packed *end = l < t->size
1082                         ? rw_aux_to_bkey(b, t, l)
1083                         : btree_bkey_last(b, t);
1084                 struct bkey_packed *k = start;
1085
1086                 while (1) {
1087                         k = bkey_next_skip_noops(k, end);
1088                         if (k == end)
1089                                 break;
1090
1091                         if ((void *) k - (void *) start >= L1_CACHE_BYTES) {
1092                                 memmove(&rw_aux_tree(b, t)[l + 1],
1093                                         &rw_aux_tree(b, t)[l],
1094                                         (void *) &rw_aux_tree(b, t)[t->size] -
1095                                         (void *) &rw_aux_tree(b, t)[l]);
1096                                 t->size++;
1097                                 rw_aux_tree_set(b, t, l, k);
1098                                 break;
1099                         }
1100                 }
1101         }
1102
1103         bch2_bset_verify_rw_aux_tree(b, t);
1104         bset_aux_tree_verify(b);
1105 }
1106
1107 void bch2_bset_insert(struct btree *b,
1108                       struct btree_node_iter *iter,
1109                       struct bkey_packed *where,
1110                       struct bkey_i *insert,
1111                       unsigned clobber_u64s)
1112 {
1113         struct bkey_format *f = &b->format;
1114         struct bset_tree *t = bset_tree_last(b);
1115         struct bkey_packed packed, *src = bkey_to_packed(insert);
1116
1117         bch2_bset_verify_rw_aux_tree(b, t);
1118         bch2_verify_insert_pos(b, where, bkey_to_packed(insert), clobber_u64s);
1119
1120         if (bch2_bkey_pack_key(&packed, &insert->k, f))
1121                 src = &packed;
1122
1123         if (!bkey_deleted(&insert->k))
1124                 btree_keys_account_key_add(&b->nr, t - b->set, src);
1125
1126         if (src->u64s != clobber_u64s) {
1127                 u64 *src_p = where->_data + clobber_u64s;
1128                 u64 *dst_p = where->_data + src->u64s;
1129
1130                 EBUG_ON((int) le16_to_cpu(bset(b, t)->u64s) <
1131                         (int) clobber_u64s - src->u64s);
1132
1133                 memmove_u64s(dst_p, src_p, btree_bkey_last(b, t)->_data - src_p);
1134                 le16_add_cpu(&bset(b, t)->u64s, src->u64s - clobber_u64s);
1135                 set_btree_bset_end(b, t);
1136         }
1137
1138         memcpy_u64s(where, src,
1139                     bkeyp_key_u64s(f, src));
1140         memcpy_u64s(bkeyp_val(f, where), &insert->v,
1141                     bkeyp_val_u64s(f, src));
1142
1143         if (src->u64s != clobber_u64s)
1144                 bch2_bset_fix_lookup_table(b, t, where, clobber_u64s, src->u64s);
1145
1146         bch2_verify_btree_nr_keys(b);
1147 }
1148
1149 void bch2_bset_delete(struct btree *b,
1150                       struct bkey_packed *where,
1151                       unsigned clobber_u64s)
1152 {
1153         struct bset_tree *t = bset_tree_last(b);
1154         u64 *src_p = where->_data + clobber_u64s;
1155         u64 *dst_p = where->_data;
1156
1157         bch2_bset_verify_rw_aux_tree(b, t);
1158
1159         EBUG_ON(le16_to_cpu(bset(b, t)->u64s) < clobber_u64s);
1160
1161         memmove_u64s_down(dst_p, src_p, btree_bkey_last(b, t)->_data - src_p);
1162         le16_add_cpu(&bset(b, t)->u64s, -clobber_u64s);
1163         set_btree_bset_end(b, t);
1164
1165         bch2_bset_fix_lookup_table(b, t, where, clobber_u64s, 0);
1166 }
1167
1168 /* Lookup */
1169
1170 __flatten
1171 static struct bkey_packed *bset_search_write_set(const struct btree *b,
1172                                 struct bset_tree *t,
1173                                 struct bpos *search,
1174                                 const struct bkey_packed *packed_search)
1175 {
1176         unsigned l = 0, r = t->size;
1177
1178         while (l + 1 != r) {
1179                 unsigned m = (l + r) >> 1;
1180
1181                 if (bkey_cmp(rw_aux_tree(b, t)[m].k, *search) < 0)
1182                         l = m;
1183                 else
1184                         r = m;
1185         }
1186
1187         return rw_aux_to_bkey(b, t, l);
1188 }
1189
1190 static inline void prefetch_four_cachelines(void *p)
1191 {
1192 #ifdef CONFIG_X86_64
1193         asm(".intel_syntax noprefix;"
1194             "prefetcht0 [%0 - 127 + 64 * 0];"
1195             "prefetcht0 [%0 - 127 + 64 * 1];"
1196             "prefetcht0 [%0 - 127 + 64 * 2];"
1197             "prefetcht0 [%0 - 127 + 64 * 3];"
1198             ".att_syntax prefix;"
1199             :
1200             : "r" (p + 127));
1201 #else
1202         prefetch(p + L1_CACHE_BYTES * 0);
1203         prefetch(p + L1_CACHE_BYTES * 1);
1204         prefetch(p + L1_CACHE_BYTES * 2);
1205         prefetch(p + L1_CACHE_BYTES * 3);
1206 #endif
1207 }
1208
1209 static inline bool bkey_mantissa_bits_dropped(const struct btree *b,
1210                                               const struct bkey_float *f,
1211                                               unsigned idx)
1212 {
1213 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
1214         unsigned key_bits_start = b->format.key_u64s * 64 - b->nr_key_bits;
1215
1216         return f->exponent > key_bits_start;
1217 #else
1218         unsigned key_bits_end = high_bit_offset + b->nr_key_bits;
1219
1220         return f->exponent + BKEY_MANTISSA_BITS < key_bits_end;
1221 #endif
1222 }
1223
1224 __flatten
1225 static struct bkey_packed *bset_search_tree(const struct btree *b,
1226                                 const struct bset_tree *t,
1227                                 const struct bpos *search,
1228                                 const struct bkey_packed *packed_search)
1229 {
1230         struct ro_aux_tree *base = ro_aux_tree_base(b, t);
1231         struct bkey_float *f;
1232         struct bkey_packed *k;
1233         unsigned inorder, n = 1, l, r;
1234         int cmp;
1235
1236         do {
1237                 if (likely(n << 4 < t->size))
1238                         prefetch(&base->f[n << 4]);
1239
1240                 f = &base->f[n];
1241
1242                 if (!unlikely(packed_search))
1243                         goto slowpath;
1244                 if (unlikely(f->exponent >= BFLOAT_FAILED))
1245                         goto slowpath;
1246
1247                 l = f->mantissa;
1248                 r = bkey_mantissa(packed_search, f, n);
1249
1250                 if (unlikely(l == r) && bkey_mantissa_bits_dropped(b, f, n))
1251                         goto slowpath;
1252
1253                 n = n * 2 + (l < r);
1254                 continue;
1255 slowpath:
1256                 k = tree_to_bkey(b, t, n);
1257                 cmp = bkey_cmp_p_or_unp(b, k, packed_search, search);
1258                 if (!cmp)
1259                         return k;
1260
1261                 n = n * 2 + (cmp < 0);
1262         } while (n < t->size);
1263
1264         inorder = __eytzinger1_to_inorder(n >> 1, t->size, t->extra);
1265
1266         /*
1267          * n would have been the node we recursed to - the low bit tells us if
1268          * we recursed left or recursed right.
1269          */
1270         if (likely(!(n & 1))) {
1271                 --inorder;
1272                 if (unlikely(!inorder))
1273                         return btree_bkey_first(b, t);
1274
1275                 f = &base->f[eytzinger1_prev(n >> 1, t->size)];
1276         }
1277
1278         return cacheline_to_bkey(b, t, inorder, f->key_offset);
1279 }
1280
1281 static __always_inline __flatten
1282 struct bkey_packed *__bch2_bset_search(struct btree *b,
1283                                 struct bset_tree *t,
1284                                 struct bpos *search,
1285                                 const struct bkey_packed *lossy_packed_search)
1286 {
1287
1288         /*
1289          * First, we search for a cacheline, then lastly we do a linear search
1290          * within that cacheline.
1291          *
1292          * To search for the cacheline, there's three different possibilities:
1293          *  * The set is too small to have a search tree, so we just do a linear
1294          *    search over the whole set.
1295          *  * The set is the one we're currently inserting into; keeping a full
1296          *    auxiliary search tree up to date would be too expensive, so we
1297          *    use a much simpler lookup table to do a binary search -
1298          *    bset_search_write_set().
1299          *  * Or we use the auxiliary search tree we constructed earlier -
1300          *    bset_search_tree()
1301          */
1302
1303         switch (bset_aux_tree_type(t)) {
1304         case BSET_NO_AUX_TREE:
1305                 return btree_bkey_first(b, t);
1306         case BSET_RW_AUX_TREE:
1307                 return bset_search_write_set(b, t, search, lossy_packed_search);
1308         case BSET_RO_AUX_TREE:
1309                 /*
1310                  * Each node in the auxiliary search tree covers a certain range
1311                  * of bits, and keys above and below the set it covers might
1312                  * differ outside those bits - so we have to special case the
1313                  * start and end - handle that here:
1314                  */
1315
1316                 if (bkey_cmp(*search, t->max_key) > 0)
1317                         return btree_bkey_last(b, t);
1318
1319                 return bset_search_tree(b, t, search, lossy_packed_search);
1320         default:
1321                 unreachable();
1322         }
1323 }
1324
1325 static __always_inline __flatten
1326 struct bkey_packed *bch2_bset_search_linear(struct btree *b,
1327                                 struct bset_tree *t,
1328                                 struct bpos *search,
1329                                 struct bkey_packed *packed_search,
1330                                 const struct bkey_packed *lossy_packed_search,
1331                                 struct bkey_packed *m)
1332 {
1333         if (lossy_packed_search)
1334                 while (m != btree_bkey_last(b, t) &&
1335                        bkey_iter_cmp_p_or_unp(b, m,
1336                                         lossy_packed_search, search) < 0)
1337                         m = bkey_next_skip_noops(m, btree_bkey_last(b, t));
1338
1339         if (!packed_search)
1340                 while (m != btree_bkey_last(b, t) &&
1341                        bkey_iter_pos_cmp(b, m, search) < 0)
1342                         m = bkey_next_skip_noops(m, btree_bkey_last(b, t));
1343
1344         if (bch2_expensive_debug_checks) {
1345                 struct bkey_packed *prev = bch2_bkey_prev_all(b, t, m);
1346
1347                 BUG_ON(prev &&
1348                        bkey_iter_cmp_p_or_unp(b, prev,
1349                                         packed_search, search) >= 0);
1350         }
1351
1352         return m;
1353 }
1354
1355 /*
1356  * Returns the first key greater than or equal to @search
1357  */
1358 static __always_inline __flatten
1359 struct bkey_packed *bch2_bset_search(struct btree *b,
1360                                 struct bset_tree *t,
1361                                 struct bpos *search,
1362                                 struct bkey_packed *packed_search,
1363                                 const struct bkey_packed *lossy_packed_search)
1364 {
1365         struct bkey_packed *m = __bch2_bset_search(b, t, search,
1366                                                    lossy_packed_search);
1367
1368         return bch2_bset_search_linear(b, t, search,
1369                                  packed_search, lossy_packed_search, m);
1370 }
1371
1372 /* Btree node iterator */
1373
1374 static inline void __bch2_btree_node_iter_push(struct btree_node_iter *iter,
1375                               struct btree *b,
1376                               const struct bkey_packed *k,
1377                               const struct bkey_packed *end)
1378 {
1379         if (k != end) {
1380                 struct btree_node_iter_set *pos;
1381
1382                 btree_node_iter_for_each(iter, pos)
1383                         ;
1384
1385                 BUG_ON(pos >= iter->data + ARRAY_SIZE(iter->data));
1386                 *pos = (struct btree_node_iter_set) {
1387                         __btree_node_key_to_offset(b, k),
1388                         __btree_node_key_to_offset(b, end)
1389                 };
1390         }
1391 }
1392
1393 void bch2_btree_node_iter_push(struct btree_node_iter *iter,
1394                                struct btree *b,
1395                                const struct bkey_packed *k,
1396                                const struct bkey_packed *end)
1397 {
1398         __bch2_btree_node_iter_push(iter, b, k, end);
1399         bch2_btree_node_iter_sort(iter, b);
1400 }
1401
1402 noinline __flatten __attribute__((cold))
1403 static void btree_node_iter_init_pack_failed(struct btree_node_iter *iter,
1404                               struct btree *b, struct bpos *search)
1405 {
1406         struct bset_tree *t;
1407
1408         trace_bkey_pack_pos_fail(search);
1409
1410         for_each_bset(b, t)
1411                 __bch2_btree_node_iter_push(iter, b,
1412                         bch2_bset_search(b, t, search, NULL, NULL),
1413                         btree_bkey_last(b, t));
1414
1415         bch2_btree_node_iter_sort(iter, b);
1416 }
1417
1418 /**
1419  * bch_btree_node_iter_init - initialize a btree node iterator, starting from a
1420  * given position
1421  *
1422  * Main entry point to the lookup code for individual btree nodes:
1423  *
1424  * NOTE:
1425  *
1426  * When you don't filter out deleted keys, btree nodes _do_ contain duplicate
1427  * keys. This doesn't matter for most code, but it does matter for lookups.
1428  *
1429  * Some adjacent keys with a string of equal keys:
1430  *      i j k k k k l m
1431  *
1432  * If you search for k, the lookup code isn't guaranteed to return you any
1433  * specific k. The lookup code is conceptually doing a binary search and
1434  * iterating backwards is very expensive so if the pivot happens to land at the
1435  * last k that's what you'll get.
1436  *
1437  * This works out ok, but it's something to be aware of:
1438  *
1439  *  - For non extents, we guarantee that the live key comes last - see
1440  *    btree_node_iter_cmp(), keys_out_of_order(). So the duplicates you don't
1441  *    see will only be deleted keys you don't care about.
1442  *
1443  *  - For extents, deleted keys sort last (see the comment at the top of this
1444  *    file). But when you're searching for extents, you actually want the first
1445  *    key strictly greater than your search key - an extent that compares equal
1446  *    to the search key is going to have 0 sectors after the search key.
1447  *
1448  *    But this does mean that we can't just search for
1449  *    bkey_successor(start_of_range) to get the first extent that overlaps with
1450  *    the range we want - if we're unlucky and there's an extent that ends
1451  *    exactly where we searched, then there could be a deleted key at the same
1452  *    position and we'd get that when we search instead of the preceding extent
1453  *    we needed.
1454  *
1455  *    So we've got to search for start_of_range, then after the lookup iterate
1456  *    past any extents that compare equal to the position we searched for.
1457  */
1458 __flatten
1459 void bch2_btree_node_iter_init(struct btree_node_iter *iter,
1460                                struct btree *b, struct bpos *search)
1461 {
1462         struct bkey_packed p, *packed_search = NULL;
1463         struct btree_node_iter_set *pos = iter->data;
1464         struct bkey_packed *k[MAX_BSETS];
1465         unsigned i;
1466
1467         EBUG_ON(bkey_cmp(*search, b->data->min_key) < 0);
1468         bset_aux_tree_verify(b);
1469
1470         memset(iter, 0, sizeof(*iter));
1471
1472         switch (bch2_bkey_pack_pos_lossy(&p, *search, b)) {
1473         case BKEY_PACK_POS_EXACT:
1474                 packed_search = &p;
1475                 break;
1476         case BKEY_PACK_POS_SMALLER:
1477                 packed_search = NULL;
1478                 break;
1479         case BKEY_PACK_POS_FAIL:
1480                 btree_node_iter_init_pack_failed(iter, b, search);
1481                 return;
1482         }
1483
1484         for (i = 0; i < b->nsets; i++) {
1485                 k[i] = __bch2_bset_search(b, b->set + i, search, &p);
1486                 prefetch_four_cachelines(k[i]);
1487         }
1488
1489         for (i = 0; i < b->nsets; i++) {
1490                 struct bset_tree *t = b->set + i;
1491                 struct bkey_packed *end = btree_bkey_last(b, t);
1492
1493                 k[i] = bch2_bset_search_linear(b, t, search,
1494                                                packed_search, &p, k[i]);
1495                 if (k[i] != end)
1496                         *pos++ = (struct btree_node_iter_set) {
1497                                 __btree_node_key_to_offset(b, k[i]),
1498                                 __btree_node_key_to_offset(b, end)
1499                         };
1500         }
1501
1502         bch2_btree_node_iter_sort(iter, b);
1503 }
1504
1505 void bch2_btree_node_iter_init_from_start(struct btree_node_iter *iter,
1506                                           struct btree *b)
1507 {
1508         struct bset_tree *t;
1509
1510         memset(iter, 0, sizeof(*iter));
1511
1512         for_each_bset(b, t)
1513                 __bch2_btree_node_iter_push(iter, b,
1514                                            btree_bkey_first(b, t),
1515                                            btree_bkey_last(b, t));
1516         bch2_btree_node_iter_sort(iter, b);
1517 }
1518
1519 struct bkey_packed *bch2_btree_node_iter_bset_pos(struct btree_node_iter *iter,
1520                                                   struct btree *b,
1521                                                   struct bset_tree *t)
1522 {
1523         struct btree_node_iter_set *set;
1524
1525         btree_node_iter_for_each(iter, set)
1526                 if (set->end == t->end_offset)
1527                         return __btree_node_offset_to_key(b, set->k);
1528
1529         return btree_bkey_last(b, t);
1530 }
1531
1532 static inline bool btree_node_iter_sort_two(struct btree_node_iter *iter,
1533                                             struct btree *b,
1534                                             unsigned first)
1535 {
1536         bool ret;
1537
1538         if ((ret = (btree_node_iter_cmp(b,
1539                                         iter->data[first],
1540                                         iter->data[first + 1]) > 0)))
1541                 swap(iter->data[first], iter->data[first + 1]);
1542         return ret;
1543 }
1544
1545 void bch2_btree_node_iter_sort(struct btree_node_iter *iter,
1546                                struct btree *b)
1547 {
1548         /* unrolled bubble sort: */
1549
1550         if (!__btree_node_iter_set_end(iter, 2)) {
1551                 btree_node_iter_sort_two(iter, b, 0);
1552                 btree_node_iter_sort_two(iter, b, 1);
1553         }
1554
1555         if (!__btree_node_iter_set_end(iter, 1))
1556                 btree_node_iter_sort_two(iter, b, 0);
1557 }
1558
1559 void bch2_btree_node_iter_set_drop(struct btree_node_iter *iter,
1560                                    struct btree_node_iter_set *set)
1561 {
1562         struct btree_node_iter_set *last =
1563                 iter->data + ARRAY_SIZE(iter->data) - 1;
1564
1565         memmove(&set[0], &set[1], (void *) last - (void *) set);
1566         *last = (struct btree_node_iter_set) { 0, 0 };
1567 }
1568
1569 static inline void __bch2_btree_node_iter_advance(struct btree_node_iter *iter,
1570                                                   struct btree *b)
1571 {
1572         iter->data->k += __bch2_btree_node_iter_peek_all(iter, b)->u64s;
1573
1574         EBUG_ON(iter->data->k > iter->data->end);
1575
1576         while (!__btree_node_iter_set_end(iter, 0) &&
1577                !__bch2_btree_node_iter_peek_all(iter, b)->u64s)
1578                 iter->data->k++;
1579
1580         if (unlikely(__btree_node_iter_set_end(iter, 0))) {
1581                 bch2_btree_node_iter_set_drop(iter, iter->data);
1582                 return;
1583         }
1584
1585         if (__btree_node_iter_set_end(iter, 1))
1586                 return;
1587
1588         if (!btree_node_iter_sort_two(iter, b, 0))
1589                 return;
1590
1591         if (__btree_node_iter_set_end(iter, 2))
1592                 return;
1593
1594         btree_node_iter_sort_two(iter, b, 1);
1595 }
1596
1597 void bch2_btree_node_iter_advance(struct btree_node_iter *iter,
1598                                   struct btree *b)
1599 {
1600         if (bch2_expensive_debug_checks) {
1601                 bch2_btree_node_iter_verify(iter, b);
1602                 bch2_btree_node_iter_next_check(iter, b);
1603         }
1604
1605         __bch2_btree_node_iter_advance(iter, b);
1606 }
1607
1608 /*
1609  * Expensive:
1610  */
1611 struct bkey_packed *bch2_btree_node_iter_prev_all(struct btree_node_iter *iter,
1612                                                   struct btree *b)
1613 {
1614         struct bkey_packed *k, *prev = NULL;
1615         struct btree_node_iter_set *set;
1616         struct bset_tree *t;
1617         unsigned end = 0;
1618
1619         if (bch2_expensive_debug_checks)
1620                 bch2_btree_node_iter_verify(iter, b);
1621
1622         for_each_bset(b, t) {
1623                 k = bch2_bkey_prev_all(b, t,
1624                         bch2_btree_node_iter_bset_pos(iter, b, t));
1625                 if (k &&
1626                     (!prev || bkey_iter_cmp(b, k, prev) > 0)) {
1627                         prev = k;
1628                         end = t->end_offset;
1629                 }
1630         }
1631
1632         if (!prev)
1633                 return NULL;
1634
1635         /*
1636          * We're manually memmoving instead of just calling sort() to ensure the
1637          * prev we picked ends up in slot 0 - sort won't necessarily put it
1638          * there because of duplicate deleted keys:
1639          */
1640         btree_node_iter_for_each(iter, set)
1641                 if (set->end == end)
1642                         goto found;
1643
1644         BUG_ON(set != &iter->data[__btree_node_iter_used(iter)]);
1645 found:
1646         BUG_ON(set >= iter->data + ARRAY_SIZE(iter->data));
1647
1648         memmove(&iter->data[1],
1649                 &iter->data[0],
1650                 (void *) set - (void *) &iter->data[0]);
1651
1652         iter->data[0].k = __btree_node_key_to_offset(b, prev);
1653         iter->data[0].end = end;
1654
1655         if (bch2_expensive_debug_checks)
1656                 bch2_btree_node_iter_verify(iter, b);
1657         return prev;
1658 }
1659
1660 struct bkey_packed *bch2_btree_node_iter_prev(struct btree_node_iter *iter,
1661                                               struct btree *b)
1662 {
1663         struct bkey_packed *prev;
1664
1665         do {
1666                 prev = bch2_btree_node_iter_prev_all(iter, b);
1667         } while (prev && bkey_deleted(prev));
1668
1669         return prev;
1670 }
1671
1672 struct bkey_s_c bch2_btree_node_iter_peek_unpack(struct btree_node_iter *iter,
1673                                                  struct btree *b,
1674                                                  struct bkey *u)
1675 {
1676         struct bkey_packed *k = bch2_btree_node_iter_peek(iter, b);
1677
1678         return k ? bkey_disassemble(b, k, u) : bkey_s_c_null;
1679 }
1680
1681 /* Mergesort */
1682
1683 void bch2_btree_keys_stats(struct btree *b, struct bset_stats *stats)
1684 {
1685         struct bset_tree *t;
1686
1687         for_each_bset(b, t) {
1688                 enum bset_aux_tree_type type = bset_aux_tree_type(t);
1689                 size_t j;
1690
1691                 stats->sets[type].nr++;
1692                 stats->sets[type].bytes += le16_to_cpu(bset(b, t)->u64s) *
1693                         sizeof(u64);
1694
1695                 if (bset_has_ro_aux_tree(t)) {
1696                         stats->floats += t->size - 1;
1697
1698                         for (j = 1; j < t->size; j++)
1699                                 stats->failed +=
1700                                         bkey_float(b, t, j)->exponent ==
1701                                         BFLOAT_FAILED;
1702                 }
1703         }
1704 }
1705
1706 void bch2_bfloat_to_text(struct printbuf *out, struct btree *b,
1707                          struct bkey_packed *k)
1708 {
1709         struct bset_tree *t = bch2_bkey_to_bset(b, k);
1710         struct bkey uk;
1711         unsigned j, inorder;
1712
1713         if (out->pos != out->end)
1714                 *out->pos = '\0';
1715
1716         if (!bset_has_ro_aux_tree(t))
1717                 return;
1718
1719         inorder = bkey_to_cacheline(b, t, k);
1720         if (!inorder || inorder >= t->size)
1721                 return;
1722
1723         j = __inorder_to_eytzinger1(inorder, t->size, t->extra);
1724         if (k != tree_to_bkey(b, t, j))
1725                 return;
1726
1727         switch (bkey_float(b, t, j)->exponent) {
1728         case BFLOAT_FAILED:
1729                 uk = bkey_unpack_key(b, k);
1730                 pr_buf(out,
1731                        "    failed unpacked at depth %u\n"
1732                        "\t%llu:%llu\n",
1733                        ilog2(j),
1734                        uk.p.inode, uk.p.offset);
1735                 break;
1736         }
1737 }