git.sesse.net Git - bcachefs-tools-debian/blob - libbcachefs/bset.c

   1 /*
   2  * Code for working with individual keys, and sorted sets of keys with in a
   3  * btree node
   4  *
   5  * Copyright 2012 Google, Inc.
   6  */
   7
   8 #include "bcachefs.h"
   9 #include "btree_cache.h"
  10 #include "bset.h"
  11 #include "eytzinger.h"
  12 #include "util.h"
  13
  14 #include <asm/unaligned.h>
  15 #include <linux/dynamic_fault.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 struct bset_tree *bch2_bkey_to_bset(struct btree *b, struct bkey_packed *k)
  28 {
  29         unsigned offset = __btree_node_key_to_offset(b, k);
  30         struct bset_tree *t;
  31
  32         for_each_bset(b, t)
  33                 if (offset <= t->end_offset) {
  34                         EBUG_ON(offset < btree_bkey_first_offset(t));
  35                         return t;
  36                 }
  37
  38         BUG();
  39 }
  40
  41 /*
  42  * There are never duplicate live keys in the btree - but including keys that
  43  * have been flagged as deleted (and will be cleaned up later) we _will_ see
  44  * duplicates.
  45  *
  46  * Thus the sort order is: usual key comparison first, but for keys that compare
  47  * equal the deleted key(s) come first, and the (at most one) live version comes
  48  * last.
  49  *
  50  * The main reason for this is insertion: to handle overwrites, we first iterate
  51  * over keys that compare equal to our insert key, and then insert immediately
  52  * prior to the first key greater than the key we're inserting - our insert
  53  * position will be after all keys that compare equal to our insert key, which
  54  * by the time we actually do the insert will all be deleted.
  55  */
  56
  57 void bch2_dump_bset(struct btree *b, struct bset *i, unsigned set)
  58 {
  59         struct bkey_packed *_k, *_n;
  60         struct bkey k, n;
  61         char buf[120];
  62
  63         if (!i->u64s)
  64                 return;
  65
  66         for (_k = i->start, k = bkey_unpack_key(b, _k);
  67              _k < vstruct_last(i);
  68              _k = _n, k = n) {
  69                 _n = bkey_next(_k);
  70
  71                 bch2_bkey_to_text(&PBUF(buf), &k);
  72                 printk(KERN_ERR "block %u key %5u: %s\n", set,
  73                        __btree_node_key_to_offset(b, _k), buf);
  74
  75                 if (_n == vstruct_last(i))
  76                         continue;
  77
  78                 n = bkey_unpack_key(b, _n);
  79
  80                 if (bkey_cmp(bkey_start_pos(&n), k.p) < 0) {
  81                         printk(KERN_ERR "Key skipped backwards\n");
  82                         continue;
  83                 }
  84
  85                 /*
  86                  * Weird check for duplicate non extent keys: extents are
  87                  * deleted iff they have 0 size, so if it has zero size and it's
  88                  * not deleted these aren't extents:
  89                  */
  90                 if (((!k.size && !bkey_deleted(&k)) ||
  91                      (!n.size && !bkey_deleted(&n))) &&
  92                     !bkey_deleted(&k) &&
  93                     !bkey_cmp(n.p, k.p))
  94                         printk(KERN_ERR "Duplicate keys\n");
  95         }
  96 }
  97
  98 void bch2_dump_btree_node(struct btree *b)
  99 {
 100         struct bset_tree *t;
 101
 102         console_lock();
 103         for_each_bset(b, t)
 104                 bch2_dump_bset(b, bset(b, t), t - b->set);
 105         console_unlock();
 106 }
 107
 108 void bch2_dump_btree_node_iter(struct btree *b,
 109                               struct btree_node_iter *iter)
 110 {
 111         struct btree_node_iter_set *set;
 112
 113         printk(KERN_ERR "btree node iter with %u sets:\n", b->nsets);
 114
 115         btree_node_iter_for_each(iter, set) {
 116                 struct bkey_packed *k = __btree_node_offset_to_key(b, set->k);
 117                 struct bset_tree *t = bch2_bkey_to_bset(b, k);
 118                 struct bkey uk = bkey_unpack_key(b, k);
 119                 char buf[100];
 120
 121                 bch2_bkey_to_text(&PBUF(buf), &uk);
 122                 printk(KERN_ERR "set %zu key %zi/%u: %s\n", t - b->set,
 123                        k->_data - bset(b, t)->_data, bset(b, t)->u64s, buf);
 124         }
 125 }
 126
 127 #ifdef CONFIG_BCACHEFS_DEBUG
 128
 129 void __bch2_verify_btree_nr_keys(struct btree *b)
 130 {
 131         struct bset_tree *t;
 132         struct bkey_packed *k;
 133         struct btree_nr_keys nr = { 0 };
 134
 135         for_each_bset(b, t)
 136                 for (k = btree_bkey_first(b, t);
 137                      k != btree_bkey_last(b, t);
 138                      k = bkey_next(k))
 139                         if (!bkey_whiteout(k))
 140                                 btree_keys_account_key_add(&nr, t - b->set, k);
 141
 142         BUG_ON(memcmp(&nr, &b->nr, sizeof(nr)));
 143 }
 144
 145 static void bch2_btree_node_iter_next_check(struct btree_node_iter *_iter,
 146                                             struct btree *b)
 147 {
 148         struct btree_node_iter iter = *_iter;
 149         const struct bkey_packed *k, *n;
 150
 151         k = bch2_btree_node_iter_peek_all(&iter, b);
 152         __bch2_btree_node_iter_advance(&iter, b);
 153         n = bch2_btree_node_iter_peek_all(&iter, b);
 154
 155         bkey_unpack_key(b, k);
 156
 157         if (n &&
 158             bkey_iter_cmp(b, k, n) > 0) {
 159                 struct btree_node_iter_set *set;
 160                 struct bkey ku = bkey_unpack_key(b, k);
 161                 struct bkey nu = bkey_unpack_key(b, n);
 162                 char buf1[80], buf2[80];
 163
 164                 bch2_dump_btree_node(b);
 165                 bch2_bkey_to_text(&PBUF(buf1), &ku);
 166                 bch2_bkey_to_text(&PBUF(buf2), &nu);
 167                 printk(KERN_ERR "out of order/overlapping:\n%s\n%s\n",
 168                        buf1, buf2);
 169                 printk(KERN_ERR "iter was:");
 170
 171                 btree_node_iter_for_each(_iter, set) {
 172                         struct bkey_packed *k = __btree_node_offset_to_key(b, set->k);
 173                         struct bset_tree *t = bch2_bkey_to_bset(b, k);
 174                         printk(" [%zi %zi]", t - b->set,
 175                                k->_data - bset(b, t)->_data);
 176                 }
 177                 panic("\n");
 178         }
 179 }
 180
 181 void bch2_btree_node_iter_verify(struct btree_node_iter *iter,
 182                                  struct btree *b)
 183 {
 184         struct btree_node_iter_set *set, *s2;
 185         struct bset_tree *t;
 186
 187         /* Verify no duplicates: */
 188         btree_node_iter_for_each(iter, set)
 189                 btree_node_iter_for_each(iter, s2)
 190                         BUG_ON(set != s2 && set->end == s2->end);
 191
 192         /* Verify that set->end is correct: */
 193         btree_node_iter_for_each(iter, set) {
 194                 for_each_bset(b, t)
 195                         if (set->end == t->end_offset)
 196                                 goto found;
 197                 BUG();
 198 found:
 199                 BUG_ON(set->k < btree_bkey_first_offset(t) ||
 200                        set->k >= t->end_offset);
 201         }
 202
 203         /* Verify iterator is sorted: */
 204         btree_node_iter_for_each(iter, set)
 205                 BUG_ON(set != iter->data &&
 206                        btree_node_iter_cmp(b, set[-1], set[0]) > 0);
 207 }
 208
 209 void bch2_verify_insert_pos(struct btree *b, struct bkey_packed *where,
 210                             struct bkey_packed *insert, unsigned clobber_u64s)
 211 {
 212         struct bset_tree *t = bch2_bkey_to_bset(b, where);
 213         struct bkey_packed *prev = bch2_bkey_prev_all(b, t, where);
 214         struct bkey_packed *next = (void *) (where->_data + clobber_u64s);
 215 #if 0
 216         BUG_ON(prev &&
 217                bkey_iter_cmp(b, prev, insert) > 0);
 218 #else
 219         if (prev &&
 220             bkey_iter_cmp(b, prev, insert) > 0) {
 221                 struct bkey k1 = bkey_unpack_key(b, prev);
 222                 struct bkey k2 = bkey_unpack_key(b, insert);
 223                 char buf1[100];
 224                 char buf2[100];
 225
 226                 bch2_dump_btree_node(b);
 227                 bch2_bkey_to_text(&PBUF(buf1), &k1);
 228                 bch2_bkey_to_text(&PBUF(buf2), &k2);
 229
 230                 panic("prev > insert:\n"
 231                       "prev    key %5u %s\n"
 232                       "insert  key %5u %s\n",
 233                        __btree_node_key_to_offset(b, prev), buf1,
 234                        __btree_node_key_to_offset(b, insert), buf2);
 235         }
 236 #endif
 237 #if 0
 238         BUG_ON(next != btree_bkey_last(b, t) &&
 239                bkey_iter_cmp(b, insert, next) > 0);
 240 #else
 241         if (next != btree_bkey_last(b, t) &&
 242             bkey_iter_cmp(b, insert, next) > 0) {
 243                 struct bkey k1 = bkey_unpack_key(b, insert);
 244                 struct bkey k2 = bkey_unpack_key(b, next);
 245                 char buf1[100];
 246                 char buf2[100];
 247
 248                 bch2_dump_btree_node(b);
 249                 bch2_bkey_to_text(&PBUF(buf1), &k1);
 250                 bch2_bkey_to_text(&PBUF(buf2), &k2);
 251
 252                 panic("insert > next:\n"
 253                       "insert  key %5u %s\n"
 254                       "next    key %5u %s\n",
 255                        __btree_node_key_to_offset(b, insert), buf1,
 256                        __btree_node_key_to_offset(b, next), buf2);
 257         }
 258 #endif
 259 }
 260
 261 #else
 262
 263 static inline void bch2_btree_node_iter_next_check(struct btree_node_iter *iter,
 264                                                    struct btree *b) {}
 265
 266 #endif
 267
 268 /* Auxiliary search trees */
 269
 270 #define BFLOAT_FAILED_UNPACKED  (U8_MAX - 0)
 271 #define BFLOAT_FAILED_PREV      (U8_MAX - 1)
 272 #define BFLOAT_FAILED_OVERFLOW  (U8_MAX - 2)
 273 #define BFLOAT_FAILED           (U8_MAX - 2)
 274
 275 #define KEY_WORDS               BITS_TO_LONGS(1 << BKEY_EXPONENT_BITS)
 276
 277 struct bkey_float {
 278         u8              exponent;
 279         u8              key_offset;
 280         union {
 281                 u32     mantissa32;
 282         struct {
 283                 u16     mantissa16;
 284                 u16     _pad;
 285         };
 286         };
 287 } __packed;
 288
 289 #define BFLOAT_32BIT_NR         32U
 290
 291 static unsigned bkey_float_byte_offset(unsigned idx)
 292 {
 293         int d = (idx - BFLOAT_32BIT_NR) << 1;
 294
 295         d &= ~(d >> 31);
 296
 297         return idx * 6 - d;
 298 }
 299
 300 struct ro_aux_tree {
 301         struct bkey_float       _d[0];
 302 };
 303
 304 struct rw_aux_tree {
 305         u16             offset;
 306         struct bpos     k;
 307 };
 308
 309 /*
 310  * BSET_CACHELINE was originally intended to match the hardware cacheline size -
 311  * it used to be 64, but I realized the lookup code would touch slightly less
 312  * memory if it was 128.
 313  *
 314  * It definites the number of bytes (in struct bset) per struct bkey_float in
 315  * the auxiliar search tree - when we're done searching the bset_float tree we
 316  * have this many bytes left that we do a linear search over.
 317  *
 318  * Since (after level 5) every level of the bset_tree is on a new cacheline,
 319  * we're touching one fewer cacheline in the bset tree in exchange for one more
 320  * cacheline in the linear search - but the linear search might stop before it
 321  * gets to the second cacheline.
 322  */
 323
 324 #define BSET_CACHELINE          128
 325
 326 /* Space required for the btree node keys */
 327 static inline size_t btree_keys_bytes(struct btree *b)
 328 {
 329         return PAGE_SIZE << b->page_order;
 330 }
 331
 332 static inline size_t btree_keys_cachelines(struct btree *b)
 333 {
 334         return btree_keys_bytes(b) / BSET_CACHELINE;
 335 }
 336
 337 static inline size_t btree_aux_data_bytes(struct btree *b)
 338 {
 339         return btree_keys_cachelines(b) * 8;
 340 }
 341
 342 static inline size_t btree_aux_data_u64s(struct btree *b)
 343 {
 344         return btree_aux_data_bytes(b) / sizeof(u64);
 345 }
 346
 347 static unsigned bset_aux_tree_buf_end(const struct bset_tree *t)
 348 {
 349         BUG_ON(t->aux_data_offset == U16_MAX);
 350
 351         switch (bset_aux_tree_type(t)) {
 352         case BSET_NO_AUX_TREE:
 353                 return t->aux_data_offset;
 354         case BSET_RO_AUX_TREE:
 355                 return t->aux_data_offset +
 356                         DIV_ROUND_UP(bkey_float_byte_offset(t->size) +
 357                                      sizeof(u8) * t->size, 8);
 358         case BSET_RW_AUX_TREE:
 359                 return t->aux_data_offset +
 360                         DIV_ROUND_UP(sizeof(struct rw_aux_tree) * t->size, 8);
 361         default:
 362                 BUG();
 363         }
 364 }
 365
 366 static unsigned bset_aux_tree_buf_start(const struct btree *b,
 367                                         const struct bset_tree *t)
 368 {
 369         return t == b->set
 370                 ? DIV_ROUND_UP(b->unpack_fn_len, 8)
 371                 : bset_aux_tree_buf_end(t - 1);
 372 }
 373
 374 static void *__aux_tree_base(const struct btree *b,
 375                              const struct bset_tree *t)
 376 {
 377         return b->aux_data + t->aux_data_offset * 8;
 378 }
 379
 380 static struct ro_aux_tree *ro_aux_tree_base(const struct btree *b,
 381                                             const struct bset_tree *t)
 382 {
 383         EBUG_ON(bset_aux_tree_type(t) != BSET_RO_AUX_TREE);
 384
 385         return __aux_tree_base(b, t);
 386 }
 387
 388 static u8 *ro_aux_tree_prev(const struct btree *b,
 389                             const struct bset_tree *t)
 390 {
 391         EBUG_ON(bset_aux_tree_type(t) != BSET_RO_AUX_TREE);
 392
 393         return __aux_tree_base(b, t) + bkey_float_byte_offset(t->size);
 394 }
 395
 396 static struct bkey_float *bkey_float_get(struct ro_aux_tree *b,
 397                                          unsigned idx)
 398 {
 399         return (void *) b + bkey_float_byte_offset(idx);
 400 }
 401
 402 static struct bkey_float *bkey_float(const struct btree *b,
 403                                      const struct bset_tree *t,
 404                                      unsigned idx)
 405 {
 406         return bkey_float_get(ro_aux_tree_base(b, t), idx);
 407 }
 408
 409 static void bset_aux_tree_verify(struct btree *b)
 410 {
 411 #ifdef CONFIG_BCACHEFS_DEBUG
 412         struct bset_tree *t;
 413
 414         for_each_bset(b, t) {
 415                 if (t->aux_data_offset == U16_MAX)
 416                         continue;
 417
 418                 BUG_ON(t != b->set &&
 419                        t[-1].aux_data_offset == U16_MAX);
 420
 421                 BUG_ON(t->aux_data_offset < bset_aux_tree_buf_start(b, t));
 422                 BUG_ON(t->aux_data_offset > btree_aux_data_u64s(b));
 423                 BUG_ON(bset_aux_tree_buf_end(t) > btree_aux_data_u64s(b));
 424         }
 425 #endif
 426 }
 427
 428 /* Memory allocation */
 429
 430 void bch2_btree_keys_free(struct btree *b)
 431 {
 432         vfree(b->aux_data);
 433         b->aux_data = NULL;
 434 }
 435
 436 #ifndef PAGE_KERNEL_EXEC
 437 # define PAGE_KERNEL_EXEC PAGE_KERNEL
 438 #endif
 439
 440 int bch2_btree_keys_alloc(struct btree *b, unsigned page_order, gfp_t gfp)
 441 {
 442         b->page_order   = page_order;
 443         b->aux_data     = __vmalloc(btree_aux_data_bytes(b), gfp,
 444                                     PAGE_KERNEL_EXEC);
 445         if (!b->aux_data)
 446                 return -ENOMEM;
 447
 448         return 0;
 449 }
 450
 451 void bch2_btree_keys_init(struct btree *b, bool *expensive_debug_checks)
 452 {
 453         unsigned i;
 454
 455         b->nsets                = 0;
 456         memset(&b->nr, 0, sizeof(b->nr));
 457 #ifdef CONFIG_BCACHEFS_DEBUG
 458         b->expensive_debug_checks = expensive_debug_checks;
 459 #endif
 460         for (i = 0; i < MAX_BSETS; i++)
 461                 b->set[i].data_offset = U16_MAX;
 462
 463         bch2_bset_set_no_aux_tree(b, b->set);
 464 }
 465
 466 /* Binary tree stuff for auxiliary search trees */
 467
 468 /*
 469  * Cacheline/offset <-> bkey pointer arithmetic:
 470  *
 471  * t->tree is a binary search tree in an array; each node corresponds to a key
 472  * in one cacheline in t->set (BSET_CACHELINE bytes).
 473  *
 474  * This means we don't have to store the full index of the key that a node in
 475  * the binary tree points to; eytzinger1_to_inorder() gives us the cacheline, and
 476  * then bkey_float->m gives us the offset within that cacheline, in units of 8
 477  * bytes.
 478  *
 479  * cacheline_to_bkey() and friends abstract out all the pointer arithmetic to
 480  * make this work.
 481  *
 482  * To construct the bfloat for an arbitrary key we need to know what the key
 483  * immediately preceding it is: we have to check if the two keys differ in the
 484  * bits we're going to store in bkey_float->mantissa. t->prev[j] stores the size
 485  * of the previous key so we can walk backwards to it from t->tree[j]'s key.
 486  */
 487
 488 static inline void *bset_cacheline(const struct btree *b,
 489                                    const struct bset_tree *t,
 490                                    unsigned cacheline)
 491 {
 492         return (void *) round_down((unsigned long) btree_bkey_first(b, t),
 493                                    L1_CACHE_BYTES) +
 494                 cacheline * BSET_CACHELINE;
 495 }
 496
 497 static struct bkey_packed *cacheline_to_bkey(const struct btree *b,
 498                                              const struct bset_tree *t,
 499                                              unsigned cacheline,
 500                                              unsigned offset)
 501 {
 502         return bset_cacheline(b, t, cacheline) + offset * 8;
 503 }
 504
 505 static unsigned bkey_to_cacheline(const struct btree *b,
 506                                   const struct bset_tree *t,
 507                                   const struct bkey_packed *k)
 508 {
 509         return ((void *) k - bset_cacheline(b, t, 0)) / BSET_CACHELINE;
 510 }
 511
 512 static ssize_t __bkey_to_cacheline_offset(const struct btree *b,
 513                                           const struct bset_tree *t,
 514                                           unsigned cacheline,
 515                                           const struct bkey_packed *k)
 516 {
 517         return (u64 *) k - (u64 *) bset_cacheline(b, t, cacheline);
 518 }
 519
 520 static unsigned bkey_to_cacheline_offset(const struct btree *b,
 521                                          const struct bset_tree *t,
 522                                          unsigned cacheline,
 523                                          const struct bkey_packed *k)
 524 {
 525         size_t m = __bkey_to_cacheline_offset(b, t, cacheline, k);
 526
 527         EBUG_ON(m > U8_MAX);
 528         return m;
 529 }
 530
 531 static inline struct bkey_packed *tree_to_bkey(const struct btree *b,
 532                                                const struct bset_tree *t,
 533                                                unsigned j)
 534 {
 535         return cacheline_to_bkey(b, t,
 536                         __eytzinger1_to_inorder(j, t->size, t->extra),
 537                         bkey_float(b, t, j)->key_offset);
 538 }
 539
 540 static struct bkey_packed *tree_to_prev_bkey(const struct btree *b,
 541                                              const struct bset_tree *t,
 542                                              unsigned j)
 543 {
 544         unsigned prev_u64s = ro_aux_tree_prev(b, t)[j];
 545
 546         return (void *) (tree_to_bkey(b, t, j)->_data - prev_u64s);
 547 }
 548
 549 static struct rw_aux_tree *rw_aux_tree(const struct btree *b,
 550                                        const struct bset_tree *t)
 551 {
 552         EBUG_ON(bset_aux_tree_type(t) != BSET_RW_AUX_TREE);
 553
 554         return __aux_tree_base(b, t);
 555 }
 556
 557 /*
 558  * For the write set - the one we're currently inserting keys into - we don't
 559  * maintain a full search tree, we just keep a simple lookup table in t->prev.
 560  */
 561 static struct bkey_packed *rw_aux_to_bkey(const struct btree *b,
 562                                           struct bset_tree *t,
 563                                           unsigned j)
 564 {
 565         return __btree_node_offset_to_key(b, rw_aux_tree(b, t)[j].offset);
 566 }
 567
 568 static void rw_aux_tree_set(const struct btree *b, struct bset_tree *t,
 569                             unsigned j, struct bkey_packed *k)
 570 {
 571         EBUG_ON(k >= btree_bkey_last(b, t));
 572
 573         rw_aux_tree(b, t)[j] = (struct rw_aux_tree) {
 574                 .offset = __btree_node_key_to_offset(b, k),
 575                 .k      = bkey_unpack_pos(b, k),
 576         };
 577 }
 578
 579 static void bch2_bset_verify_rw_aux_tree(struct btree *b,
 580                                         struct bset_tree *t)
 581 {
 582         struct bkey_packed *k = btree_bkey_first(b, t);
 583         unsigned j = 0;
 584
 585         if (!btree_keys_expensive_checks(b))
 586                 return;
 587
 588         BUG_ON(bset_has_ro_aux_tree(t));
 589
 590         if (!bset_has_rw_aux_tree(t))
 591                 return;
 592
 593         BUG_ON(t->size < 1);
 594         BUG_ON(rw_aux_to_bkey(b, t, j) != k);
 595
 596         goto start;
 597         while (1) {
 598                 if (rw_aux_to_bkey(b, t, j) == k) {
 599                         BUG_ON(bkey_cmp(rw_aux_tree(b, t)[j].k,
 600                                         bkey_unpack_pos(b, k)));
 601 start:
 602                         if (++j == t->size)
 603                                 break;
 604
 605                         BUG_ON(rw_aux_tree(b, t)[j].offset <=
 606                                rw_aux_tree(b, t)[j - 1].offset);
 607                 }
 608
 609                 k = bkey_next(k);
 610                 BUG_ON(k >= btree_bkey_last(b, t));
 611         }
 612 }
 613
 614 /* returns idx of first entry >= offset: */
 615 static unsigned rw_aux_tree_bsearch(struct btree *b,
 616                                     struct bset_tree *t,
 617                                     unsigned offset)
 618 {
 619         unsigned bset_offs = offset - btree_bkey_first_offset(t);
 620         unsigned bset_u64s = t->end_offset - btree_bkey_first_offset(t);
 621         unsigned idx = bset_u64s ? bset_offs * t->size / bset_u64s : 0;
 622
 623         EBUG_ON(bset_aux_tree_type(t) != BSET_RW_AUX_TREE);
 624         EBUG_ON(!t->size);
 625         EBUG_ON(idx > t->size);
 626
 627         while (idx < t->size &&
 628                rw_aux_tree(b, t)[idx].offset < offset)
 629                 idx++;
 630
 631         while (idx &&
 632                rw_aux_tree(b, t)[idx - 1].offset >= offset)
 633                 idx--;
 634
 635         EBUG_ON(idx < t->size &&
 636                 rw_aux_tree(b, t)[idx].offset < offset);
 637         EBUG_ON(idx && rw_aux_tree(b, t)[idx - 1].offset >= offset);
 638         EBUG_ON(idx + 1 < t->size &&
 639                 rw_aux_tree(b, t)[idx].offset ==
 640                 rw_aux_tree(b, t)[idx + 1].offset);
 641
 642         return idx;
 643 }
 644
 645 static inline unsigned bfloat_mantissa(const struct bkey_float *f,
 646                                        unsigned idx)
 647 {
 648         return idx < BFLOAT_32BIT_NR ? f->mantissa32 : f->mantissa16;
 649 }
 650
 651 static inline void bfloat_mantissa_set(struct bkey_float *f,
 652                                        unsigned idx, unsigned mantissa)
 653 {
 654         if (idx < BFLOAT_32BIT_NR)
 655                 f->mantissa32 = mantissa;
 656         else
 657                 f->mantissa16 = mantissa;
 658 }
 659
 660 static inline unsigned bkey_mantissa(const struct bkey_packed *k,
 661                                      const struct bkey_float *f,
 662                                      unsigned idx)
 663 {
 664         u64 v;
 665
 666         EBUG_ON(!bkey_packed(k));
 667
 668         v = get_unaligned((u64 *) (((u8 *) k->_data) + (f->exponent >> 3)));
 669
 670         /*
 671          * In little endian, we're shifting off low bits (and then the bits we
 672          * want are at the low end), in big endian we're shifting off high bits
 673          * (and then the bits we want are at the high end, so we shift them
 674          * back down):
 675          */
 676 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 677         v >>= f->exponent & 7;
 678 #else
 679         v >>= 64 - (f->exponent & 7) - (idx < BFLOAT_32BIT_NR ? 32 : 16);
 680 #endif
 681         return idx < BFLOAT_32BIT_NR ? (u32) v : (u16) v;
 682 }
 683
 684 static void make_bfloat(struct btree *b, struct bset_tree *t,
 685                         unsigned j,
 686                         struct bkey_packed *min_key,
 687                         struct bkey_packed *max_key)
 688 {
 689         struct bkey_float *f = bkey_float(b, t, j);
 690         struct bkey_packed *m = tree_to_bkey(b, t, j);
 691         struct bkey_packed *p = tree_to_prev_bkey(b, t, j);
 692         struct bkey_packed *l, *r;
 693         unsigned bits = j < BFLOAT_32BIT_NR ? 32 : 16;
 694         unsigned mantissa;
 695         int shift, exponent, high_bit;
 696
 697         EBUG_ON(bkey_next(p) != m);
 698
 699         if (is_power_of_2(j)) {
 700                 l = min_key;
 701
 702                 if (!l->u64s) {
 703                         if (!bkey_pack_pos(l, b->data->min_key, b)) {
 704                                 struct bkey_i tmp;
 705
 706                                 bkey_init(&tmp.k);
 707                                 tmp.k.p = b->data->min_key;
 708                                 bkey_copy(l, &tmp);
 709                         }
 710                 }
 711         } else {
 712                 l = tree_to_prev_bkey(b, t, j >> ffs(j));
 713
 714                 EBUG_ON(m < l);
 715         }
 716
 717         if (is_power_of_2(j + 1)) {
 718                 r = max_key;
 719
 720                 if (!r->u64s) {
 721                         if (!bkey_pack_pos(r, t->max_key, b)) {
 722                                 struct bkey_i tmp;
 723
 724                                 bkey_init(&tmp.k);
 725                                 tmp.k.p = t->max_key;
 726                                 bkey_copy(r, &tmp);
 727                         }
 728                 }
 729         } else {
 730                 r = tree_to_bkey(b, t, j >> (ffz(j) + 1));
 731
 732                 EBUG_ON(m > r);
 733         }
 734
 735         /*
 736          * for failed bfloats, the lookup code falls back to comparing against
 737          * the original key.
 738          */
 739
 740         if (!bkey_packed(l) || !bkey_packed(r) ||
 741             !bkey_packed(p) || !bkey_packed(m) ||
 742             !b->nr_key_bits) {
 743                 f->exponent = BFLOAT_FAILED_UNPACKED;
 744                 return;
 745         }
 746
 747         /*
 748          * The greatest differing bit of l and r is the first bit we must
 749          * include in the bfloat mantissa we're creating in order to do
 750          * comparisons - that bit always becomes the high bit of
 751          * bfloat->mantissa, and thus the exponent we're calculating here is
 752          * the position of what will become the low bit in bfloat->mantissa:
 753          *
 754          * Note that this may be negative - we may be running off the low end
 755          * of the key: we handle this later:
 756          */
 757         high_bit = max(bch2_bkey_greatest_differing_bit(b, l, r),
 758                        min_t(unsigned, bits, b->nr_key_bits) - 1);
 759         exponent = high_bit - (bits - 1);
 760
 761         /*
 762          * Then we calculate the actual shift value, from the start of the key
 763          * (k->_data), to get the key bits starting at exponent:
 764          */
 765 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 766         shift = (int) (b->format.key_u64s * 64 - b->nr_key_bits) + exponent;
 767
 768         EBUG_ON(shift + bits > b->format.key_u64s * 64);
 769 #else
 770         shift = high_bit_offset +
 771                 b->nr_key_bits -
 772                 exponent -
 773                 bits;
 774
 775         EBUG_ON(shift < KEY_PACKED_BITS_START);
 776 #endif
 777         EBUG_ON(shift < 0 || shift >= BFLOAT_FAILED);
 778
 779         f->exponent = shift;
 780         mantissa = bkey_mantissa(m, f, j);
 781
 782         /*
 783          * If we've got garbage bits, set them to all 1s - it's legal for the
 784          * bfloat to compare larger than the original key, but not smaller:
 785          */
 786         if (exponent < 0)
 787                 mantissa |= ~(~0U << -exponent);
 788
 789         bfloat_mantissa_set(f, j, mantissa);
 790
 791         /*
 792          * The bfloat must be able to tell its key apart from the previous key -
 793          * if its key and the previous key don't differ in the required bits,
 794          * flag as failed - unless the keys are actually equal, in which case
 795          * we aren't required to return a specific one:
 796          */
 797         if (exponent > 0 &&
 798             bfloat_mantissa(f, j) == bkey_mantissa(p, f, j) &&
 799             bkey_cmp_packed(b, p, m)) {
 800                 f->exponent = BFLOAT_FAILED_PREV;
 801                 return;
 802         }
 803
 804         /*
 805          * f->mantissa must compare >= the original key - for transitivity with
 806          * the comparison in bset_search_tree. If we're dropping set bits,
 807          * increment it:
 808          */
 809         if (exponent > (int) bch2_bkey_ffs(b, m)) {
 810                 if (j < BFLOAT_32BIT_NR
 811                     ? f->mantissa32 == U32_MAX
 812                     : f->mantissa16 == U16_MAX)
 813                         f->exponent = BFLOAT_FAILED_OVERFLOW;
 814
 815                 if (j < BFLOAT_32BIT_NR)
 816                         f->mantissa32++;
 817                 else
 818                         f->mantissa16++;
 819         }
 820 }
 821
 822 /* bytes remaining - only valid for last bset: */
 823 static unsigned __bset_tree_capacity(struct btree *b, struct bset_tree *t)
 824 {
 825         bset_aux_tree_verify(b);
 826
 827         return btree_aux_data_bytes(b) - t->aux_data_offset * sizeof(u64);
 828 }
 829
 830 static unsigned bset_ro_tree_capacity(struct btree *b, struct bset_tree *t)
 831 {
 832         unsigned bytes = __bset_tree_capacity(b, t);
 833
 834         if (bytes < 7 * BFLOAT_32BIT_NR)
 835                 return bytes / 7;
 836
 837         bytes -= 7 * BFLOAT_32BIT_NR;
 838
 839         return BFLOAT_32BIT_NR + bytes / 5;
 840 }
 841
 842 static unsigned bset_rw_tree_capacity(struct btree *b, struct bset_tree *t)
 843 {
 844         return __bset_tree_capacity(b, t) / sizeof(struct rw_aux_tree);
 845 }
 846
 847 static void __build_rw_aux_tree(struct btree *b, struct bset_tree *t)
 848 {
 849         struct bkey_packed *k;
 850
 851         t->size = 1;
 852         t->extra = BSET_RW_AUX_TREE_VAL;
 853         rw_aux_tree(b, t)[0].offset =
 854                 __btree_node_key_to_offset(b, btree_bkey_first(b, t));
 855
 856         for (k = btree_bkey_first(b, t);
 857              k != btree_bkey_last(b, t);
 858              k = bkey_next(k)) {
 859                 if (t->size == bset_rw_tree_capacity(b, t))
 860                         break;
 861
 862                 if ((void *) k - (void *) rw_aux_to_bkey(b, t, t->size - 1) >
 863                     L1_CACHE_BYTES)
 864                         rw_aux_tree_set(b, t, t->size++, k);
 865         }
 866 }
 867
 868 static void __build_ro_aux_tree(struct btree *b, struct bset_tree *t)
 869 {
 870         struct bkey_packed *prev = NULL, *k = btree_bkey_first(b, t);
 871         struct bkey_packed min_key, max_key;
 872         unsigned j, cacheline = 1;
 873
 874         /* signal to make_bfloat() that they're uninitialized: */
 875         min_key.u64s = max_key.u64s = 0;
 876
 877         t->size = min(bkey_to_cacheline(b, t, btree_bkey_last(b, t)),
 878                       bset_ro_tree_capacity(b, t));
 879 retry:
 880         if (t->size < 2) {
 881                 t->size = 0;
 882                 t->extra = BSET_NO_AUX_TREE_VAL;
 883                 return;
 884         }
 885
 886         t->extra = (t->size - rounddown_pow_of_two(t->size - 1)) << 1;
 887
 888         /* First we figure out where the first key in each cacheline is */
 889         eytzinger1_for_each(j, t->size) {
 890                 while (bkey_to_cacheline(b, t, k) < cacheline)
 891                         prev = k, k = bkey_next(k);
 892
 893                 if (k >= btree_bkey_last(b, t)) {
 894                         /* XXX: this path sucks */
 895                         t->size--;
 896                         goto retry;
 897                 }
 898
 899                 ro_aux_tree_prev(b, t)[j] = prev->u64s;
 900                 bkey_float(b, t, j)->key_offset =
 901                         bkey_to_cacheline_offset(b, t, cacheline++, k);
 902
 903                 EBUG_ON(tree_to_prev_bkey(b, t, j) != prev);
 904                 EBUG_ON(tree_to_bkey(b, t, j) != k);
 905         }
 906
 907         while (bkey_next(k) != btree_bkey_last(b, t))
 908                 k = bkey_next(k);
 909
 910         t->max_key = bkey_unpack_pos(b, k);
 911
 912         /* Then we build the tree */
 913         eytzinger1_for_each(j, t->size)
 914                 make_bfloat(b, t, j, &min_key, &max_key);
 915 }
 916
 917 static void bset_alloc_tree(struct btree *b, struct bset_tree *t)
 918 {
 919         struct bset_tree *i;
 920
 921         for (i = b->set; i != t; i++)
 922                 BUG_ON(bset_has_rw_aux_tree(i));
 923
 924         bch2_bset_set_no_aux_tree(b, t);
 925
 926         /* round up to next cacheline: */
 927         t->aux_data_offset = round_up(bset_aux_tree_buf_start(b, t),
 928                                       SMP_CACHE_BYTES / sizeof(u64));
 929
 930         bset_aux_tree_verify(b);
 931 }
 932
 933 void bch2_bset_build_aux_tree(struct btree *b, struct bset_tree *t,
 934                              bool writeable)
 935 {
 936         if (writeable
 937             ? bset_has_rw_aux_tree(t)
 938             : bset_has_ro_aux_tree(t))
 939                 return;
 940
 941         bset_alloc_tree(b, t);
 942
 943         if (!__bset_tree_capacity(b, t))
 944                 return;
 945
 946         if (writeable)
 947                 __build_rw_aux_tree(b, t);
 948         else
 949                 __build_ro_aux_tree(b, t);
 950
 951         bset_aux_tree_verify(b);
 952 }
 953
 954 void bch2_bset_init_first(struct btree *b, struct bset *i)
 955 {
 956         struct bset_tree *t;
 957
 958         BUG_ON(b->nsets);
 959
 960         memset(i, 0, sizeof(*i));
 961         get_random_bytes(&i->seq, sizeof(i->seq));
 962         SET_BSET_BIG_ENDIAN(i, CPU_BIG_ENDIAN);
 963
 964         t = &b->set[b->nsets++];
 965         set_btree_bset(b, t, i);
 966 }
 967
 968 void bch2_bset_init_next(struct bch_fs *c, struct btree *b,
 969                          struct btree_node_entry *bne)
 970 {
 971         struct bset *i = &bne->keys;
 972         struct bset_tree *t;
 973
 974         BUG_ON(bset_byte_offset(b, bne) >= btree_bytes(c));
 975         BUG_ON((void *) bne < (void *) btree_bkey_last(b, bset_tree_last(b)));
 976         BUG_ON(b->nsets >= MAX_BSETS);
 977
 978         memset(i, 0, sizeof(*i));
 979         i->seq = btree_bset_first(b)->seq;
 980         SET_BSET_BIG_ENDIAN(i, CPU_BIG_ENDIAN);
 981
 982         t = &b->set[b->nsets++];
 983         set_btree_bset(b, t, i);
 984 }
 985
 986 /*
 987  * find _some_ key in the same bset as @k that precedes @k - not necessarily the
 988  * immediate predecessor:
 989  */
 990 static struct bkey_packed *__bkey_prev(struct btree *b, struct bset_tree *t,
 991                                        struct bkey_packed *k)
 992 {
 993         struct bkey_packed *p;
 994         unsigned offset;
 995         int j;
 996
 997         EBUG_ON(k < btree_bkey_first(b, t) ||
 998                 k > btree_bkey_last(b, t));
 999
1000         if (k == btree_bkey_first(b, t))
1001                 return NULL;
1002
1003         switch (bset_aux_tree_type(t)) {
1004         case BSET_NO_AUX_TREE:
1005                 p = btree_bkey_first(b, t);
1006                 break;
1007         case BSET_RO_AUX_TREE:
1008                 j = min_t(unsigned, t->size - 1, bkey_to_cacheline(b, t, k));
1009
1010                 do {
1011                         p = j ? tree_to_bkey(b, t,
1012                                         __inorder_to_eytzinger1(j--,
1013                                                         t->size, t->extra))
1014                               : btree_bkey_first(b, t);
1015                 } while (p >= k);
1016                 break;
1017         case BSET_RW_AUX_TREE:
1018                 offset = __btree_node_key_to_offset(b, k);
1019                 j = rw_aux_tree_bsearch(b, t, offset);
1020                 p = j ? rw_aux_to_bkey(b, t, j - 1)
1021                       : btree_bkey_first(b, t);
1022                 break;
1023         }
1024
1025         return p;
1026 }
1027
1028 struct bkey_packed *bch2_bkey_prev_filter(struct btree *b,
1029                                           struct bset_tree *t,
1030                                           struct bkey_packed *k,
1031                                           unsigned min_key_type)
1032 {
1033         struct bkey_packed *p, *i, *ret = NULL, *orig_k = k;
1034
1035         while ((p = __bkey_prev(b, t, k)) && !ret) {
1036                 for (i = p; i != k; i = bkey_next(i))
1037                         if (i->type >= min_key_type)
1038                                 ret = i;
1039
1040                 k = p;
1041         }
1042
1043         if (btree_keys_expensive_checks(b)) {
1044                 BUG_ON(ret >= orig_k);
1045
1046                 for (i = ret ? bkey_next(ret) : btree_bkey_first(b, t);
1047                      i != orig_k;
1048                      i = bkey_next(i))
1049                         BUG_ON(i->type >= min_key_type);
1050         }
1051
1052         return ret;
1053 }
1054
1055 /* Insert */
1056
1057 static void rw_aux_tree_fix_invalidated_key(struct btree *b,
1058                                             struct bset_tree *t,
1059                                             struct bkey_packed *k)
1060 {
1061         unsigned offset = __btree_node_key_to_offset(b, k);
1062         unsigned j = rw_aux_tree_bsearch(b, t, offset);
1063
1064         if (j < t->size &&
1065             rw_aux_tree(b, t)[j].offset == offset)
1066                 rw_aux_tree_set(b, t, j, k);
1067
1068         bch2_bset_verify_rw_aux_tree(b, t);
1069 }
1070
1071 static void ro_aux_tree_fix_invalidated_key(struct btree *b,
1072                                             struct bset_tree *t,
1073                                             struct bkey_packed *k)
1074 {
1075         struct bkey_packed min_key, max_key;
1076         unsigned inorder, j;
1077
1078         EBUG_ON(bset_aux_tree_type(t) != BSET_RO_AUX_TREE);
1079
1080         /* signal to make_bfloat() that they're uninitialized: */
1081         min_key.u64s = max_key.u64s = 0;
1082
1083         if (bkey_next(k) == btree_bkey_last(b, t)) {
1084                 t->max_key = bkey_unpack_pos(b, k);
1085
1086                 for (j = 1; j < t->size; j = j * 2 + 1)
1087                         make_bfloat(b, t, j, &min_key, &max_key);
1088         }
1089
1090         inorder = bkey_to_cacheline(b, t, k);
1091
1092         if (inorder &&
1093             inorder < t->size) {
1094                 j = __inorder_to_eytzinger1(inorder, t->size, t->extra);
1095
1096                 if (k == tree_to_bkey(b, t, j)) {
1097                         /* Fix the node this key corresponds to */
1098                         make_bfloat(b, t, j, &min_key, &max_key);
1099
1100                         /* Children for which this key is the right boundary */
1101                         for (j = eytzinger1_left_child(j);
1102                              j < t->size;
1103                              j = eytzinger1_right_child(j))
1104                                 make_bfloat(b, t, j, &min_key, &max_key);
1105                 }
1106         }
1107
1108         if (inorder + 1 < t->size) {
1109                 j = __inorder_to_eytzinger1(inorder + 1, t->size, t->extra);
1110
1111                 if (k == tree_to_prev_bkey(b, t, j)) {
1112                         make_bfloat(b, t, j, &min_key, &max_key);
1113
1114                         /* Children for which this key is the left boundary */
1115                         for (j = eytzinger1_right_child(j);
1116                              j < t->size;
1117                              j = eytzinger1_left_child(j))
1118                                 make_bfloat(b, t, j, &min_key, &max_key);
1119                 }
1120         }
1121 }
1122
1123 /**
1124  * bch2_bset_fix_invalidated_key() - given an existing  key @k that has been
1125  * modified, fix any auxiliary search tree by remaking all the nodes in the
1126  * auxiliary search tree that @k corresponds to
1127  */
1128 void bch2_bset_fix_invalidated_key(struct btree *b, struct bkey_packed *k)
1129 {
1130         struct bset_tree *t = bch2_bkey_to_bset(b, k);
1131
1132         switch (bset_aux_tree_type(t)) {
1133         case BSET_NO_AUX_TREE:
1134                 break;
1135         case BSET_RO_AUX_TREE:
1136                 ro_aux_tree_fix_invalidated_key(b, t, k);
1137                 break;
1138         case BSET_RW_AUX_TREE:
1139                 rw_aux_tree_fix_invalidated_key(b, t, k);
1140                 break;
1141         }
1142 }
1143
1144 static void bch2_bset_fix_lookup_table(struct btree *b,
1145                                        struct bset_tree *t,
1146                                        struct bkey_packed *_where,
1147                                        unsigned clobber_u64s,
1148                                        unsigned new_u64s)
1149 {
1150         int shift = new_u64s - clobber_u64s;
1151         unsigned l, j, where = __btree_node_key_to_offset(b, _where);
1152
1153         EBUG_ON(bset_has_ro_aux_tree(t));
1154
1155         if (!bset_has_rw_aux_tree(t))
1156                 return;
1157
1158         /* returns first entry >= where */
1159         l = rw_aux_tree_bsearch(b, t, where);
1160
1161         if (!l) /* never delete first entry */
1162                 l++;
1163         else if (l < t->size &&
1164                  where < t->end_offset &&
1165                  rw_aux_tree(b, t)[l].offset == where)
1166                 rw_aux_tree_set(b, t, l++, _where);
1167
1168         /* l now > where */
1169
1170         for (j = l;
1171              j < t->size &&
1172              rw_aux_tree(b, t)[j].offset < where + clobber_u64s;
1173              j++)
1174                 ;
1175
1176         if (j < t->size &&
1177             rw_aux_tree(b, t)[j].offset + shift ==
1178             rw_aux_tree(b, t)[l - 1].offset)
1179                 j++;
1180
1181         memmove(&rw_aux_tree(b, t)[l],
1182                 &rw_aux_tree(b, t)[j],
1183                 (void *) &rw_aux_tree(b, t)[t->size] -
1184                 (void *) &rw_aux_tree(b, t)[j]);
1185         t->size -= j - l;
1186
1187         for (j = l; j < t->size; j++)
1188                rw_aux_tree(b, t)[j].offset += shift;
1189
1190         EBUG_ON(l < t->size &&
1191                 rw_aux_tree(b, t)[l].offset ==
1192                 rw_aux_tree(b, t)[l - 1].offset);
1193
1194         if (t->size < bset_rw_tree_capacity(b, t) &&
1195             (l < t->size
1196              ? rw_aux_tree(b, t)[l].offset
1197              : t->end_offset) -
1198             rw_aux_tree(b, t)[l - 1].offset >
1199             L1_CACHE_BYTES / sizeof(u64)) {
1200                 struct bkey_packed *start = rw_aux_to_bkey(b, t, l - 1);
1201                 struct bkey_packed *end = l < t->size
1202                         ? rw_aux_to_bkey(b, t, l)
1203                         : btree_bkey_last(b, t);
1204                 struct bkey_packed *k = start;
1205
1206                 while (1) {
1207                         k = bkey_next(k);
1208                         if (k == end)
1209                                 break;
1210
1211                         if ((void *) k - (void *) start >= L1_CACHE_BYTES) {
1212                                 memmove(&rw_aux_tree(b, t)[l + 1],
1213                                         &rw_aux_tree(b, t)[l],
1214                                         (void *) &rw_aux_tree(b, t)[t->size] -
1215                                         (void *) &rw_aux_tree(b, t)[l]);
1216                                 t->size++;
1217                                 rw_aux_tree_set(b, t, l, k);
1218                                 break;
1219                         }
1220                 }
1221         }
1222
1223         bch2_bset_verify_rw_aux_tree(b, t);
1224         bset_aux_tree_verify(b);
1225 }
1226
1227 void bch2_bset_insert(struct btree *b,
1228                       struct btree_node_iter *iter,
1229                       struct bkey_packed *where,
1230                       struct bkey_i *insert,
1231                       unsigned clobber_u64s)
1232 {
1233         struct bkey_format *f = &b->format;
1234         struct bset_tree *t = bset_tree_last(b);
1235         struct bkey_packed packed, *src = bkey_to_packed(insert);
1236
1237         bch2_bset_verify_rw_aux_tree(b, t);
1238         bch2_verify_insert_pos(b, where, bkey_to_packed(insert), clobber_u64s);
1239
1240         if (bch2_bkey_pack_key(&packed, &insert->k, f))
1241                 src = &packed;
1242
1243         if (!bkey_whiteout(&insert->k))
1244                 btree_keys_account_key_add(&b->nr, t - b->set, src);
1245
1246         if (src->u64s != clobber_u64s) {
1247                 u64 *src_p = where->_data + clobber_u64s;
1248                 u64 *dst_p = where->_data + src->u64s;
1249
1250                 EBUG_ON((int) le16_to_cpu(bset(b, t)->u64s) <
1251                         (int) clobber_u64s - src->u64s);
1252
1253                 memmove_u64s(dst_p, src_p, btree_bkey_last(b, t)->_data - src_p);
1254                 le16_add_cpu(&bset(b, t)->u64s, src->u64s - clobber_u64s);
1255                 set_btree_bset_end(b, t);
1256         }
1257
1258         memcpy_u64s(where, src,
1259                     bkeyp_key_u64s(f, src));
1260         memcpy_u64s(bkeyp_val(f, where), &insert->v,
1261                     bkeyp_val_u64s(f, src));
1262
1263         bch2_bset_fix_lookup_table(b, t, where, clobber_u64s, src->u64s);
1264
1265         bch2_verify_btree_nr_keys(b);
1266 }
1267
1268 void bch2_bset_delete(struct btree *b,
1269                       struct bkey_packed *where,
1270                       unsigned clobber_u64s)
1271 {
1272         struct bset_tree *t = bset_tree_last(b);
1273         u64 *src_p = where->_data + clobber_u64s;
1274         u64 *dst_p = where->_data;
1275
1276         bch2_bset_verify_rw_aux_tree(b, t);
1277
1278         EBUG_ON(le16_to_cpu(bset(b, t)->u64s) < clobber_u64s);
1279
1280         memmove_u64s_down(dst_p, src_p, btree_bkey_last(b, t)->_data - src_p);
1281         le16_add_cpu(&bset(b, t)->u64s, -clobber_u64s);
1282         set_btree_bset_end(b, t);
1283
1284         bch2_bset_fix_lookup_table(b, t, where, clobber_u64s, 0);
1285 }
1286
1287 /* Lookup */
1288
1289 __flatten
1290 static struct bkey_packed *bset_search_write_set(const struct btree *b,
1291                                 struct bset_tree *t,
1292                                 struct bpos *search,
1293                                 const struct bkey_packed *packed_search)
1294 {
1295         unsigned l = 0, r = t->size;
1296
1297         while (l + 1 != r) {
1298                 unsigned m = (l + r) >> 1;
1299
1300                 if (bkey_cmp(rw_aux_tree(b, t)[m].k, *search) < 0)
1301                         l = m;
1302                 else
1303                         r = m;
1304         }
1305
1306         return rw_aux_to_bkey(b, t, l);
1307 }
1308
1309 noinline
1310 static int bset_search_tree_slowpath(const struct btree *b,
1311                                 struct bset_tree *t, struct bpos *search,
1312                                 const struct bkey_packed *packed_search,
1313                                 unsigned n)
1314 {
1315         return bkey_cmp_p_or_unp(b, tree_to_bkey(b, t, n),
1316                                  packed_search, search) < 0;
1317 }
1318
1319 __flatten
1320 static struct bkey_packed *bset_search_tree(const struct btree *b,
1321                                 struct bset_tree *t,
1322                                 struct bpos *search,
1323                                 const struct bkey_packed *packed_search)
1324 {
1325         struct ro_aux_tree *base = ro_aux_tree_base(b, t);
1326         struct bkey_float *f = bkey_float_get(base, 1);
1327         void *p;
1328         unsigned inorder, n = 1;
1329
1330         while (1) {
1331                 if (likely(n << 4 < t->size)) {
1332                         p = bkey_float_get(base, n << 4);
1333                         prefetch(p);
1334                 } else if (n << 3 < t->size) {
1335                         inorder = __eytzinger1_to_inorder(n, t->size, t->extra);
1336                         p = bset_cacheline(b, t, inorder);
1337 #ifdef CONFIG_X86_64
1338                         asm(".intel_syntax noprefix;"
1339                             "prefetcht0 [%0 - 127 + 64 * 0];"
1340                             "prefetcht0 [%0 - 127 + 64 * 1];"
1341                             "prefetcht0 [%0 - 127 + 64 * 2];"
1342                             "prefetcht0 [%0 - 127 + 64 * 3];"
1343                             ".att_syntax prefix;"
1344                             :
1345                             : "r" (p + 127));
1346 #else
1347                         prefetch(p + L1_CACHE_BYTES * 0);
1348                         prefetch(p + L1_CACHE_BYTES * 1);
1349                         prefetch(p + L1_CACHE_BYTES * 2);
1350                         prefetch(p + L1_CACHE_BYTES * 3);
1351 #endif
1352                 } else if (n >= t->size)
1353                         break;
1354
1355                 f = bkey_float_get(base, n);
1356
1357                 if (packed_search &&
1358                     likely(f->exponent < BFLOAT_FAILED))
1359                         n = n * 2 + (bfloat_mantissa(f, n) <
1360                                      bkey_mantissa(packed_search, f, n));
1361                 else
1362                         n = n * 2 + bset_search_tree_slowpath(b, t,
1363                                                 search, packed_search, n);
1364         } while (n < t->size);
1365
1366         inorder = __eytzinger1_to_inorder(n >> 1, t->size, t->extra);
1367
1368         /*
1369          * n would have been the node we recursed to - the low bit tells us if
1370          * we recursed left or recursed right.
1371          */
1372         if (n & 1) {
1373                 return cacheline_to_bkey(b, t, inorder, f->key_offset);
1374         } else {
1375                 if (--inorder) {
1376                         n = eytzinger1_prev(n >> 1, t->size);
1377                         f = bkey_float_get(base, n);
1378                         return cacheline_to_bkey(b, t, inorder, f->key_offset);
1379                 } else
1380                         return btree_bkey_first(b, t);
1381         }
1382 }
1383
1384 /*
1385  * Returns the first key greater than or equal to @search
1386  */
1387 __always_inline __flatten
1388 static struct bkey_packed *bch2_bset_search(struct btree *b,
1389                                 struct bset_tree *t,
1390                                 struct bpos *search,
1391                                 struct bkey_packed *packed_search,
1392                                 const struct bkey_packed *lossy_packed_search)
1393 {
1394         struct bkey_packed *m;
1395
1396         /*
1397          * First, we search for a cacheline, then lastly we do a linear search
1398          * within that cacheline.
1399          *
1400          * To search for the cacheline, there's three different possibilities:
1401          *  * The set is too small to have a search tree, so we just do a linear
1402          *    search over the whole set.
1403          *  * The set is the one we're currently inserting into; keeping a full
1404          *    auxiliary search tree up to date would be too expensive, so we
1405          *    use a much simpler lookup table to do a binary search -
1406          *    bset_search_write_set().
1407          *  * Or we use the auxiliary search tree we constructed earlier -
1408          *    bset_search_tree()
1409          */
1410
1411         switch (bset_aux_tree_type(t)) {
1412         case BSET_NO_AUX_TREE:
1413                 m = btree_bkey_first(b, t);
1414                 break;
1415         case BSET_RW_AUX_TREE:
1416                 m = bset_search_write_set(b, t, search, lossy_packed_search);
1417                 break;
1418         case BSET_RO_AUX_TREE:
1419                 /*
1420                  * Each node in the auxiliary search tree covers a certain range
1421                  * of bits, and keys above and below the set it covers might
1422                  * differ outside those bits - so we have to special case the
1423                  * start and end - handle that here:
1424                  */
1425
1426                 if (bkey_cmp(*search, t->max_key) > 0)
1427                         return btree_bkey_last(b, t);
1428
1429                 m = bset_search_tree(b, t, search, lossy_packed_search);
1430                 break;
1431         }
1432
1433         if (lossy_packed_search)
1434                 while (m != btree_bkey_last(b, t) &&
1435                        bkey_iter_cmp_p_or_unp(b, search, lossy_packed_search,
1436                                               m) > 0)
1437                         m = bkey_next(m);
1438
1439         if (!packed_search)
1440                 while (m != btree_bkey_last(b, t) &&
1441                        bkey_iter_pos_cmp(b, search, m) > 0)
1442                         m = bkey_next(m);
1443
1444         if (btree_keys_expensive_checks(b)) {
1445                 struct bkey_packed *prev = bch2_bkey_prev_all(b, t, m);
1446
1447                 BUG_ON(prev &&
1448                        bkey_iter_cmp_p_or_unp(b, search, packed_search,
1449                                               prev) <= 0);
1450         }
1451
1452         return m;
1453 }
1454
1455 /* Btree node iterator */
1456
1457 static inline void __bch2_btree_node_iter_push(struct btree_node_iter *iter,
1458                               struct btree *b,
1459                               const struct bkey_packed *k,
1460                               const struct bkey_packed *end)
1461 {
1462         if (k != end) {
1463                 struct btree_node_iter_set *pos;
1464
1465                 btree_node_iter_for_each(iter, pos)
1466                         ;
1467
1468                 BUG_ON(pos >= iter->data + ARRAY_SIZE(iter->data));
1469                 *pos = (struct btree_node_iter_set) {
1470                         __btree_node_key_to_offset(b, k),
1471                         __btree_node_key_to_offset(b, end)
1472                 };
1473         }
1474 }
1475
1476 void bch2_btree_node_iter_push(struct btree_node_iter *iter,
1477                                struct btree *b,
1478                                const struct bkey_packed *k,
1479                                const struct bkey_packed *end)
1480 {
1481         __bch2_btree_node_iter_push(iter, b, k, end);
1482         bch2_btree_node_iter_sort(iter, b);
1483 }
1484
1485 noinline __flatten __attribute__((cold))
1486 static void btree_node_iter_init_pack_failed(struct btree_node_iter *iter,
1487                               struct btree *b, struct bpos *search)
1488 {
1489         struct bset_tree *t;
1490
1491         trace_bkey_pack_pos_fail(search);
1492
1493         for_each_bset(b, t)
1494                 __bch2_btree_node_iter_push(iter, b,
1495                         bch2_bset_search(b, t, search, NULL, NULL),
1496                         btree_bkey_last(b, t));
1497
1498         bch2_btree_node_iter_sort(iter, b);
1499 }
1500
1501 /**
1502  * bch_btree_node_iter_init - initialize a btree node iterator, starting from a
1503  * given position
1504  *
1505  * Main entry point to the lookup code for individual btree nodes:
1506  *
1507  * NOTE:
1508  *
1509  * When you don't filter out deleted keys, btree nodes _do_ contain duplicate
1510  * keys. This doesn't matter for most code, but it does matter for lookups.
1511  *
1512  * Some adjacent keys with a string of equal keys:
1513  *      i j k k k k l m
1514  *
1515  * If you search for k, the lookup code isn't guaranteed to return you any
1516  * specific k. The lookup code is conceptually doing a binary search and
1517  * iterating backwards is very expensive so if the pivot happens to land at the
1518  * last k that's what you'll get.
1519  *
1520  * This works out ok, but it's something to be aware of:
1521  *
1522  *  - For non extents, we guarantee that the live key comes last - see
1523  *    btree_node_iter_cmp(), keys_out_of_order(). So the duplicates you don't
1524  *    see will only be deleted keys you don't care about.
1525  *
1526  *  - For extents, deleted keys sort last (see the comment at the top of this
1527  *    file). But when you're searching for extents, you actually want the first
1528  *    key strictly greater than your search key - an extent that compares equal
1529  *    to the search key is going to have 0 sectors after the search key.
1530  *
1531  *    But this does mean that we can't just search for
1532  *    bkey_successor(start_of_range) to get the first extent that overlaps with
1533  *    the range we want - if we're unlucky and there's an extent that ends
1534  *    exactly where we searched, then there could be a deleted key at the same
1535  *    position and we'd get that when we search instead of the preceding extent
1536  *    we needed.
1537  *
1538  *    So we've got to search for start_of_range, then after the lookup iterate
1539  *    past any extents that compare equal to the position we searched for.
1540  */
1541 void bch2_btree_node_iter_init(struct btree_node_iter *iter,
1542                                struct btree *b, struct bpos *search)
1543 {
1544         struct bset_tree *t;
1545         struct bkey_packed p, *packed_search = NULL;
1546
1547         EBUG_ON(bkey_cmp(*search, b->data->min_key) < 0);
1548         bset_aux_tree_verify(b);
1549
1550         memset(iter, 0, sizeof(*iter));
1551
1552         switch (bch2_bkey_pack_pos_lossy(&p, *search, b)) {
1553         case BKEY_PACK_POS_EXACT:
1554                 packed_search = &p;
1555                 break;
1556         case BKEY_PACK_POS_SMALLER:
1557                 packed_search = NULL;
1558                 break;
1559         case BKEY_PACK_POS_FAIL:
1560                 btree_node_iter_init_pack_failed(iter, b, search);
1561                 return;
1562         }
1563
1564         for_each_bset(b, t)
1565                 __bch2_btree_node_iter_push(iter, b,
1566                                            bch2_bset_search(b, t, search,
1567                                                             packed_search, &p),
1568                                            btree_bkey_last(b, t));
1569
1570         bch2_btree_node_iter_sort(iter, b);
1571 }
1572
1573 void bch2_btree_node_iter_init_from_start(struct btree_node_iter *iter,
1574                                           struct btree *b)
1575 {
1576         struct bset_tree *t;
1577
1578         memset(iter, 0, sizeof(*iter));
1579
1580         for_each_bset(b, t)
1581                 __bch2_btree_node_iter_push(iter, b,
1582                                            btree_bkey_first(b, t),
1583                                            btree_bkey_last(b, t));
1584         bch2_btree_node_iter_sort(iter, b);
1585 }
1586
1587 struct bkey_packed *bch2_btree_node_iter_bset_pos(struct btree_node_iter *iter,
1588                                                   struct btree *b,
1589                                                   struct bset_tree *t)
1590 {
1591         struct btree_node_iter_set *set;
1592
1593         btree_node_iter_for_each(iter, set)
1594                 if (set->end == t->end_offset)
1595                         return __btree_node_offset_to_key(b, set->k);
1596
1597         return btree_bkey_last(b, t);
1598 }
1599
1600 static inline bool btree_node_iter_sort_two(struct btree_node_iter *iter,
1601                                             struct btree *b,
1602                                             unsigned first)
1603 {
1604         bool ret;
1605
1606         if ((ret = (btree_node_iter_cmp(b,
1607                                         iter->data[first],
1608                                         iter->data[first + 1]) > 0)))
1609                 swap(iter->data[first], iter->data[first + 1]);
1610         return ret;
1611 }
1612
1613 void bch2_btree_node_iter_sort(struct btree_node_iter *iter,
1614                                struct btree *b)
1615 {
1616         /* unrolled bubble sort: */
1617
1618         if (!__btree_node_iter_set_end(iter, 2)) {
1619                 btree_node_iter_sort_two(iter, b, 0);
1620                 btree_node_iter_sort_two(iter, b, 1);
1621         }
1622
1623         if (!__btree_node_iter_set_end(iter, 1))
1624                 btree_node_iter_sort_two(iter, b, 0);
1625 }
1626
1627 void bch2_btree_node_iter_set_drop(struct btree_node_iter *iter,
1628                                    struct btree_node_iter_set *set)
1629 {
1630         struct btree_node_iter_set *last =
1631                 iter->data + ARRAY_SIZE(iter->data) - 1;
1632
1633         memmove(&set[0], &set[1], (void *) last - (void *) set);
1634         *last = (struct btree_node_iter_set) { 0, 0 };
1635 }
1636
1637 static inline void __bch2_btree_node_iter_advance(struct btree_node_iter *iter,
1638                                                   struct btree *b)
1639 {
1640         iter->data->k += __bch2_btree_node_iter_peek_all(iter, b)->u64s;
1641
1642         EBUG_ON(iter->data->k > iter->data->end);
1643
1644         if (unlikely(__btree_node_iter_set_end(iter, 0))) {
1645                 bch2_btree_node_iter_set_drop(iter, iter->data);
1646                 return;
1647         }
1648
1649         if (__btree_node_iter_set_end(iter, 1))
1650                 return;
1651
1652         if (!btree_node_iter_sort_two(iter, b, 0))
1653                 return;
1654
1655         if (__btree_node_iter_set_end(iter, 2))
1656                 return;
1657
1658         btree_node_iter_sort_two(iter, b, 1);
1659 }
1660
1661 void bch2_btree_node_iter_advance(struct btree_node_iter *iter,
1662                                   struct btree *b)
1663 {
1664         if (btree_keys_expensive_checks(b)) {
1665                 bch2_btree_node_iter_verify(iter, b);
1666                 bch2_btree_node_iter_next_check(iter, b);
1667         }
1668
1669         __bch2_btree_node_iter_advance(iter, b);
1670 }
1671
1672 static inline unsigned __btree_node_iter_used(struct btree_node_iter *iter)
1673 {
1674         unsigned n = ARRAY_SIZE(iter->data);
1675
1676         while (n && __btree_node_iter_set_end(iter, n - 1))
1677                 --n;
1678
1679         return n;
1680 }
1681
1682 /*
1683  * Expensive:
1684  */
1685 struct bkey_packed *bch2_btree_node_iter_prev_filter(struct btree_node_iter *iter,
1686                                                      struct btree *b,
1687                                                      unsigned min_key_type)
1688 {
1689         struct bkey_packed *k, *prev = NULL;
1690         struct bkey_packed *orig_pos = bch2_btree_node_iter_peek_all(iter, b);
1691         struct btree_node_iter_set *set;
1692         struct bset_tree *t;
1693         unsigned end = 0;
1694
1695         bch2_btree_node_iter_verify(iter, b);
1696
1697         for_each_bset(b, t) {
1698                 k = bch2_bkey_prev_filter(b, t,
1699                         bch2_btree_node_iter_bset_pos(iter, b, t),
1700                         min_key_type);
1701                 if (k &&
1702                     (!prev || bkey_iter_cmp(b, k, prev) > 0)) {
1703                         prev = k;
1704                         end = t->end_offset;
1705                 }
1706         }
1707
1708         if (!prev)
1709                 goto out;
1710
1711         /*
1712          * We're manually memmoving instead of just calling sort() to ensure the
1713          * prev we picked ends up in slot 0 - sort won't necessarily put it
1714          * there because of duplicate deleted keys:
1715          */
1716         btree_node_iter_for_each(iter, set)
1717                 if (set->end == end)
1718                         goto found;
1719
1720         BUG_ON(set != &iter->data[__btree_node_iter_used(iter)]);
1721 found:
1722         BUG_ON(set >= iter->data + ARRAY_SIZE(iter->data));
1723
1724         memmove(&iter->data[1],
1725                 &iter->data[0],
1726                 (void *) set - (void *) &iter->data[0]);
1727
1728         iter->data[0].k = __btree_node_key_to_offset(b, prev);
1729         iter->data[0].end = end;
1730 out:
1731         if (btree_keys_expensive_checks(b)) {
1732                 struct btree_node_iter iter2 = *iter;
1733
1734                 if (prev)
1735                         __bch2_btree_node_iter_advance(&iter2, b);
1736
1737                 while ((k = bch2_btree_node_iter_peek_all(&iter2, b)) != orig_pos) {
1738                         BUG_ON(k->type >= min_key_type);
1739                         __bch2_btree_node_iter_advance(&iter2, b);
1740                 }
1741         }
1742
1743         return prev;
1744 }
1745
1746 struct bkey_s_c bch2_btree_node_iter_peek_unpack(struct btree_node_iter *iter,
1747                                                  struct btree *b,
1748                                                  struct bkey *u)
1749 {
1750         struct bkey_packed *k = bch2_btree_node_iter_peek(iter, b);
1751
1752         return k ? bkey_disassemble(b, k, u) : bkey_s_c_null;
1753 }
1754
1755 /* Mergesort */
1756
1757 void bch2_btree_keys_stats(struct btree *b, struct bset_stats *stats)
1758 {
1759         struct bset_tree *t;
1760
1761         for_each_bset(b, t) {
1762                 enum bset_aux_tree_type type = bset_aux_tree_type(t);
1763                 size_t j;
1764
1765                 stats->sets[type].nr++;
1766                 stats->sets[type].bytes += le16_to_cpu(bset(b, t)->u64s) *
1767                         sizeof(u64);
1768
1769                 if (bset_has_ro_aux_tree(t)) {
1770                         stats->floats += t->size - 1;
1771
1772                         for (j = 1; j < t->size; j++)
1773                                 switch (bkey_float(b, t, j)->exponent) {
1774                                 case BFLOAT_FAILED_UNPACKED:
1775                                         stats->failed_unpacked++;
1776                                         break;
1777                                 case BFLOAT_FAILED_PREV:
1778                                         stats->failed_prev++;
1779                                         break;
1780                                 case BFLOAT_FAILED_OVERFLOW:
1781                                         stats->failed_overflow++;
1782                                         break;
1783                                 }
1784                 }
1785         }
1786 }
1787
1788 void bch2_bfloat_to_text(struct printbuf *out, struct btree *b,
1789                          struct bkey_packed *k)
1790 {
1791         struct bset_tree *t = bch2_bkey_to_bset(b, k);
1792         struct bkey_packed *l, *r, *p;
1793         struct bkey uk, up;
1794         char buf1[200], buf2[200];
1795         unsigned j, inorder;
1796
1797         if (out->pos != out->end)
1798                 *out->pos = '\0';
1799
1800         if (!bset_has_ro_aux_tree(t))
1801                 return;
1802
1803         inorder = bkey_to_cacheline(b, t, k);
1804         if (!inorder || inorder >= t->size)
1805                 return;
1806
1807         j = __inorder_to_eytzinger1(inorder, t->size, t->extra);
1808         if (k != tree_to_bkey(b, t, j))
1809                 return;
1810
1811         switch (bkey_float(b, t, j)->exponent) {
1812         case BFLOAT_FAILED_UNPACKED:
1813                 uk = bkey_unpack_key(b, k);
1814                 pr_buf(out,
1815                        "    failed unpacked at depth %u\n"
1816                        "\t%llu:%llu\n",
1817                        ilog2(j),
1818                        uk.p.inode, uk.p.offset);
1819                 break;
1820         case BFLOAT_FAILED_PREV:
1821                 p = tree_to_prev_bkey(b, t, j);
1822                 l = is_power_of_2(j)
1823                         ? btree_bkey_first(b, t)
1824                         : tree_to_prev_bkey(b, t, j >> ffs(j));
1825                 r = is_power_of_2(j + 1)
1826                         ? bch2_bkey_prev_all(b, t, btree_bkey_last(b, t))
1827                         : tree_to_bkey(b, t, j >> (ffz(j) + 1));
1828
1829                 up = bkey_unpack_key(b, p);
1830                 uk = bkey_unpack_key(b, k);
1831                 bch2_to_binary(buf1, high_word(&b->format, p), b->nr_key_bits);
1832                 bch2_to_binary(buf2, high_word(&b->format, k), b->nr_key_bits);
1833
1834                 pr_buf(out,
1835                        "    failed prev at depth %u\n"
1836                        "\tkey starts at bit %u but first differing bit at %u\n"
1837                        "\t%llu:%llu\n"
1838                        "\t%llu:%llu\n"
1839                        "\t%s\n"
1840                        "\t%s\n",
1841                        ilog2(j),
1842                        bch2_bkey_greatest_differing_bit(b, l, r),
1843                        bch2_bkey_greatest_differing_bit(b, p, k),
1844                        uk.p.inode, uk.p.offset,
1845                        up.p.inode, up.p.offset,
1846                        buf1, buf2);
1847                 break;
1848         case BFLOAT_FAILED_OVERFLOW:
1849                 uk = bkey_unpack_key(b, k);
1850                 pr_buf(out,
1851                        "    failed overflow at depth %u\n"
1852                        "\t%llu:%llu\n",
1853                        ilog2(j),
1854                        uk.p.inode, uk.p.offset);
1855                 break;
1856         }
1857 }