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

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include "bcachefs.h"
   4 #include "bkey_methods.h"
   5 #include "bkey_buf.h"
   6 #include "btree_cache.h"
   7 #include "btree_iter.h"
   8 #include "btree_key_cache.h"
   9 #include "btree_locking.h"
  10 #include "btree_update.h"
  11 #include "debug.h"
  12 #include "error.h"
  13 #include "extents.h"
  14 #include "journal.h"
  15 #include "recovery.h"
  16 #include "replicas.h"
  17 #include "subvolume.h"
  18
  19 #include <linux/prandom.h>
  20 #include <linux/prefetch.h>
  21 #include <trace/events/bcachefs.h>
  22
  23 static inline void btree_path_list_remove(struct btree_trans *, struct btree_path *);
  24 static inline void btree_path_list_add(struct btree_trans *, struct btree_path *,
  25                                        struct btree_path *);
  26
  27 static inline unsigned long btree_iter_ip_allocated(struct btree_iter *iter)
  28 {
  29 #ifdef TRACK_PATH_ALLOCATED
  30         return iter->ip_allocated;
  31 #else
  32         return 0;
  33 #endif
  34 }
  35
  36 static struct btree_path *btree_path_alloc(struct btree_trans *, struct btree_path *);
  37
  38 /*
  39  * Unlocks before scheduling
  40  * Note: does not revalidate iterator
  41  */
  42 static inline int bch2_trans_cond_resched(struct btree_trans *trans)
  43 {
  44         if (need_resched() || race_fault()) {
  45                 bch2_trans_unlock(trans);
  46                 schedule();
  47                 return bch2_trans_relock(trans);
  48         } else {
  49                 return 0;
  50         }
  51 }
  52
  53 static inline int __btree_path_cmp(const struct btree_path *l,
  54                                    enum btree_id        r_btree_id,
  55                                    bool                 r_cached,
  56                                    struct bpos          r_pos,
  57                                    unsigned             r_level)
  58 {
  59         /*
  60          * Must match lock ordering as defined by __bch2_btree_node_lock:
  61          */
  62         return   cmp_int(l->btree_id,   r_btree_id) ?:
  63                  cmp_int((int) l->cached,       (int) r_cached) ?:
  64                  bpos_cmp(l->pos,       r_pos) ?:
  65                 -cmp_int(l->level,      r_level);
  66 }
  67
  68 static inline int btree_path_cmp(const struct btree_path *l,
  69                                  const struct btree_path *r)
  70 {
  71         return __btree_path_cmp(l, r->btree_id, r->cached, r->pos, r->level);
  72 }
  73
  74 static inline struct bpos bkey_successor(struct btree_iter *iter, struct bpos p)
  75 {
  76         /* Are we iterating over keys in all snapshots? */
  77         if (iter->flags & BTREE_ITER_ALL_SNAPSHOTS) {
  78                 p = bpos_successor(p);
  79         } else {
  80                 p = bpos_nosnap_successor(p);
  81                 p.snapshot = iter->snapshot;
  82         }
  83
  84         return p;
  85 }
  86
  87 static inline struct bpos bkey_predecessor(struct btree_iter *iter, struct bpos p)
  88 {
  89         /* Are we iterating over keys in all snapshots? */
  90         if (iter->flags & BTREE_ITER_ALL_SNAPSHOTS) {
  91                 p = bpos_predecessor(p);
  92         } else {
  93                 p = bpos_nosnap_predecessor(p);
  94                 p.snapshot = iter->snapshot;
  95         }
  96
  97         return p;
  98 }
  99
 100 static inline struct bpos btree_iter_search_key(struct btree_iter *iter)
 101 {
 102         struct bpos pos = iter->pos;
 103
 104         if ((iter->flags & BTREE_ITER_IS_EXTENTS) &&
 105             !bkey_eq(pos, POS_MAX))
 106                 pos = bkey_successor(iter, pos);
 107         return pos;
 108 }
 109
 110 static inline bool btree_path_pos_before_node(struct btree_path *path,
 111                                               struct btree *b)
 112 {
 113         return bpos_lt(path->pos, b->data->min_key);
 114 }
 115
 116 static inline bool btree_path_pos_after_node(struct btree_path *path,
 117                                              struct btree *b)
 118 {
 119         return bpos_gt(path->pos, b->key.k.p);
 120 }
 121
 122 static inline bool btree_path_pos_in_node(struct btree_path *path,
 123                                           struct btree *b)
 124 {
 125         return path->btree_id == b->c.btree_id &&
 126                 !btree_path_pos_before_node(path, b) &&
 127                 !btree_path_pos_after_node(path, b);
 128 }
 129
 130 /* Btree iterator: */
 131
 132 #ifdef CONFIG_BCACHEFS_DEBUG
 133
 134 static void bch2_btree_path_verify_cached(struct btree_trans *trans,
 135                                           struct btree_path *path)
 136 {
 137         struct bkey_cached *ck;
 138         bool locked = btree_node_locked(path, 0);
 139
 140         if (!bch2_btree_node_relock(trans, path, 0))
 141                 return;
 142
 143         ck = (void *) path->l[0].b;
 144         BUG_ON(ck->key.btree_id != path->btree_id ||
 145                !bkey_eq(ck->key.pos, path->pos));
 146
 147         if (!locked)
 148                 btree_node_unlock(trans, path, 0);
 149 }
 150
 151 static void bch2_btree_path_verify_level(struct btree_trans *trans,
 152                                 struct btree_path *path, unsigned level)
 153 {
 154         struct btree_path_level *l;
 155         struct btree_node_iter tmp;
 156         bool locked;
 157         struct bkey_packed *p, *k;
 158         struct printbuf buf1 = PRINTBUF;
 159         struct printbuf buf2 = PRINTBUF;
 160         struct printbuf buf3 = PRINTBUF;
 161         const char *msg;
 162
 163         if (!bch2_debug_check_iterators)
 164                 return;
 165
 166         l       = &path->l[level];
 167         tmp     = l->iter;
 168         locked  = btree_node_locked(path, level);
 169
 170         if (path->cached) {
 171                 if (!level)
 172                         bch2_btree_path_verify_cached(trans, path);
 173                 return;
 174         }
 175
 176         if (!btree_path_node(path, level))
 177                 return;
 178
 179         if (!bch2_btree_node_relock_notrace(trans, path, level))
 180                 return;
 181
 182         BUG_ON(!btree_path_pos_in_node(path, l->b));
 183
 184         bch2_btree_node_iter_verify(&l->iter, l->b);
 185
 186         /*
 187          * For interior nodes, the iterator will have skipped past deleted keys:
 188          */
 189         p = level
 190                 ? bch2_btree_node_iter_prev(&tmp, l->b)
 191                 : bch2_btree_node_iter_prev_all(&tmp, l->b);
 192         k = bch2_btree_node_iter_peek_all(&l->iter, l->b);
 193
 194         if (p && bkey_iter_pos_cmp(l->b, p, &path->pos) >= 0) {
 195                 msg = "before";
 196                 goto err;
 197         }
 198
 199         if (k && bkey_iter_pos_cmp(l->b, k, &path->pos) < 0) {
 200                 msg = "after";
 201                 goto err;
 202         }
 203
 204         if (!locked)
 205                 btree_node_unlock(trans, path, level);
 206         return;
 207 err:
 208         bch2_bpos_to_text(&buf1, path->pos);
 209
 210         if (p) {
 211                 struct bkey uk = bkey_unpack_key(l->b, p);
 212
 213                 bch2_bkey_to_text(&buf2, &uk);
 214         } else {
 215                 prt_printf(&buf2, "(none)");
 216         }
 217
 218         if (k) {
 219                 struct bkey uk = bkey_unpack_key(l->b, k);
 220
 221                 bch2_bkey_to_text(&buf3, &uk);
 222         } else {
 223                 prt_printf(&buf3, "(none)");
 224         }
 225
 226         panic("path should be %s key at level %u:\n"
 227               "path pos %s\n"
 228               "prev key %s\n"
 229               "cur  key %s\n",
 230               msg, level, buf1.buf, buf2.buf, buf3.buf);
 231 }
 232
 233 static void bch2_btree_path_verify(struct btree_trans *trans,
 234                                    struct btree_path *path)
 235 {
 236         struct bch_fs *c = trans->c;
 237         unsigned i;
 238
 239         EBUG_ON(path->btree_id >= BTREE_ID_NR);
 240
 241         for (i = 0; i < (!path->cached ? BTREE_MAX_DEPTH : 1); i++) {
 242                 if (!path->l[i].b) {
 243                         BUG_ON(!path->cached &&
 244                                c->btree_roots[path->btree_id].b->c.level > i);
 245                         break;
 246                 }
 247
 248                 bch2_btree_path_verify_level(trans, path, i);
 249         }
 250
 251         bch2_btree_path_verify_locks(path);
 252 }
 253
 254 void bch2_trans_verify_paths(struct btree_trans *trans)
 255 {
 256         struct btree_path *path;
 257
 258         trans_for_each_path(trans, path)
 259                 bch2_btree_path_verify(trans, path);
 260 }
 261
 262 static void bch2_btree_iter_verify(struct btree_iter *iter)
 263 {
 264         struct btree_trans *trans = iter->trans;
 265
 266         BUG_ON(iter->btree_id >= BTREE_ID_NR);
 267
 268         BUG_ON(!!(iter->flags & BTREE_ITER_CACHED) != iter->path->cached);
 269
 270         BUG_ON((iter->flags & BTREE_ITER_IS_EXTENTS) &&
 271                (iter->flags & BTREE_ITER_ALL_SNAPSHOTS));
 272
 273         BUG_ON(!(iter->flags & __BTREE_ITER_ALL_SNAPSHOTS) &&
 274                (iter->flags & BTREE_ITER_ALL_SNAPSHOTS) &&
 275                !btree_type_has_snapshots(iter->btree_id));
 276
 277         if (iter->update_path)
 278                 bch2_btree_path_verify(trans, iter->update_path);
 279         bch2_btree_path_verify(trans, iter->path);
 280 }
 281
 282 static void bch2_btree_iter_verify_entry_exit(struct btree_iter *iter)
 283 {
 284         BUG_ON((iter->flags & BTREE_ITER_FILTER_SNAPSHOTS) &&
 285                !iter->pos.snapshot);
 286
 287         BUG_ON(!(iter->flags & BTREE_ITER_ALL_SNAPSHOTS) &&
 288                iter->pos.snapshot != iter->snapshot);
 289
 290         BUG_ON(bkey_lt(iter->pos, bkey_start_pos(&iter->k)) ||
 291                bkey_gt(iter->pos, iter->k.p));
 292 }
 293
 294 static int bch2_btree_iter_verify_ret(struct btree_iter *iter, struct bkey_s_c k)
 295 {
 296         struct btree_trans *trans = iter->trans;
 297         struct btree_iter copy;
 298         struct bkey_s_c prev;
 299         int ret = 0;
 300
 301         if (!bch2_debug_check_iterators)
 302                 return 0;
 303
 304         if (!(iter->flags & BTREE_ITER_FILTER_SNAPSHOTS))
 305                 return 0;
 306
 307         if (bkey_err(k) || !k.k)
 308                 return 0;
 309
 310         BUG_ON(!bch2_snapshot_is_ancestor(trans->c,
 311                                           iter->snapshot,
 312                                           k.k->p.snapshot));
 313
 314         bch2_trans_iter_init(trans, &copy, iter->btree_id, iter->pos,
 315                              BTREE_ITER_NOPRESERVE|
 316                              BTREE_ITER_ALL_SNAPSHOTS);
 317         prev = bch2_btree_iter_prev(&copy);
 318         if (!prev.k)
 319                 goto out;
 320
 321         ret = bkey_err(prev);
 322         if (ret)
 323                 goto out;
 324
 325         if (bkey_eq(prev.k->p, k.k->p) &&
 326             bch2_snapshot_is_ancestor(trans->c, iter->snapshot,
 327                                       prev.k->p.snapshot) > 0) {
 328                 struct printbuf buf1 = PRINTBUF, buf2 = PRINTBUF;
 329
 330                 bch2_bkey_to_text(&buf1, k.k);
 331                 bch2_bkey_to_text(&buf2, prev.k);
 332
 333                 panic("iter snap %u\n"
 334                       "k    %s\n"
 335                       "prev %s\n",
 336                       iter->snapshot,
 337                       buf1.buf, buf2.buf);
 338         }
 339 out:
 340         bch2_trans_iter_exit(trans, &copy);
 341         return ret;
 342 }
 343
 344 void bch2_assert_pos_locked(struct btree_trans *trans, enum btree_id id,
 345                             struct bpos pos, bool key_cache)
 346 {
 347         struct btree_path *path;
 348         unsigned idx;
 349         struct printbuf buf = PRINTBUF;
 350
 351         btree_trans_sort_paths(trans);
 352
 353         trans_for_each_path_inorder(trans, path, idx) {
 354                 int cmp = cmp_int(path->btree_id, id) ?:
 355                         cmp_int(path->cached, key_cache);
 356
 357                 if (cmp > 0)
 358                         break;
 359                 if (cmp < 0)
 360                         continue;
 361
 362                 if (!btree_node_locked(path, 0) ||
 363                     !path->should_be_locked)
 364                         continue;
 365
 366                 if (!key_cache) {
 367                         if (bkey_ge(pos, path->l[0].b->data->min_key) &&
 368                             bkey_le(pos, path->l[0].b->key.k.p))
 369                                 return;
 370                 } else {
 371                         if (bkey_eq(pos, path->pos))
 372                                 return;
 373                 }
 374         }
 375
 376         bch2_dump_trans_paths_updates(trans);
 377         bch2_bpos_to_text(&buf, pos);
 378
 379         panic("not locked: %s %s%s\n",
 380               bch2_btree_ids[id], buf.buf,
 381               key_cache ? " cached" : "");
 382 }
 383
 384 #else
 385
 386 static inline void bch2_btree_path_verify_level(struct btree_trans *trans,
 387                                                 struct btree_path *path, unsigned l) {}
 388 static inline void bch2_btree_path_verify(struct btree_trans *trans,
 389                                           struct btree_path *path) {}
 390 static inline void bch2_btree_iter_verify(struct btree_iter *iter) {}
 391 static inline void bch2_btree_iter_verify_entry_exit(struct btree_iter *iter) {}
 392 static inline int bch2_btree_iter_verify_ret(struct btree_iter *iter, struct bkey_s_c k) { return 0; }
 393
 394 #endif
 395
 396 /* Btree path: fixups after btree updates */
 397
 398 static void btree_node_iter_set_set_pos(struct btree_node_iter *iter,
 399                                         struct btree *b,
 400                                         struct bset_tree *t,
 401                                         struct bkey_packed *k)
 402 {
 403         struct btree_node_iter_set *set;
 404
 405         btree_node_iter_for_each(iter, set)
 406                 if (set->end == t->end_offset) {
 407                         set->k = __btree_node_key_to_offset(b, k);
 408                         bch2_btree_node_iter_sort(iter, b);
 409                         return;
 410                 }
 411
 412         bch2_btree_node_iter_push(iter, b, k, btree_bkey_last(b, t));
 413 }
 414
 415 static void __bch2_btree_path_fix_key_modified(struct btree_path *path,
 416                                                struct btree *b,
 417                                                struct bkey_packed *where)
 418 {
 419         struct btree_path_level *l = &path->l[b->c.level];
 420
 421         if (where != bch2_btree_node_iter_peek_all(&l->iter, l->b))
 422                 return;
 423
 424         if (bkey_iter_pos_cmp(l->b, where, &path->pos) < 0)
 425                 bch2_btree_node_iter_advance(&l->iter, l->b);
 426 }
 427
 428 void bch2_btree_path_fix_key_modified(struct btree_trans *trans,
 429                                       struct btree *b,
 430                                       struct bkey_packed *where)
 431 {
 432         struct btree_path *path;
 433
 434         trans_for_each_path_with_node(trans, b, path) {
 435                 __bch2_btree_path_fix_key_modified(path, b, where);
 436                 bch2_btree_path_verify_level(trans, path, b->c.level);
 437         }
 438 }
 439
 440 static void __bch2_btree_node_iter_fix(struct btree_path *path,
 441                                        struct btree *b,
 442                                        struct btree_node_iter *node_iter,
 443                                        struct bset_tree *t,
 444                                        struct bkey_packed *where,
 445                                        unsigned clobber_u64s,
 446                                        unsigned new_u64s)
 447 {
 448         const struct bkey_packed *end = btree_bkey_last(b, t);
 449         struct btree_node_iter_set *set;
 450         unsigned offset = __btree_node_key_to_offset(b, where);
 451         int shift = new_u64s - clobber_u64s;
 452         unsigned old_end = t->end_offset - shift;
 453         unsigned orig_iter_pos = node_iter->data[0].k;
 454         bool iter_current_key_modified =
 455                 orig_iter_pos >= offset &&
 456                 orig_iter_pos <= offset + clobber_u64s;
 457
 458         btree_node_iter_for_each(node_iter, set)
 459                 if (set->end == old_end)
 460                         goto found;
 461
 462         /* didn't find the bset in the iterator - might have to readd it: */
 463         if (new_u64s &&
 464             bkey_iter_pos_cmp(b, where, &path->pos) >= 0) {
 465                 bch2_btree_node_iter_push(node_iter, b, where, end);
 466                 goto fixup_done;
 467         } else {
 468                 /* Iterator is after key that changed */
 469                 return;
 470         }
 471 found:
 472         set->end = t->end_offset;
 473
 474         /* Iterator hasn't gotten to the key that changed yet: */
 475         if (set->k < offset)
 476                 return;
 477
 478         if (new_u64s &&
 479             bkey_iter_pos_cmp(b, where, &path->pos) >= 0) {
 480                 set->k = offset;
 481         } else if (set->k < offset + clobber_u64s) {
 482                 set->k = offset + new_u64s;
 483                 if (set->k == set->end)
 484                         bch2_btree_node_iter_set_drop(node_iter, set);
 485         } else {
 486                 /* Iterator is after key that changed */
 487                 set->k = (int) set->k + shift;
 488                 return;
 489         }
 490
 491         bch2_btree_node_iter_sort(node_iter, b);
 492 fixup_done:
 493         if (node_iter->data[0].k != orig_iter_pos)
 494                 iter_current_key_modified = true;
 495
 496         /*
 497          * When a new key is added, and the node iterator now points to that
 498          * key, the iterator might have skipped past deleted keys that should
 499          * come after the key the iterator now points to. We have to rewind to
 500          * before those deleted keys - otherwise
 501          * bch2_btree_node_iter_prev_all() breaks:
 502          */
 503         if (!bch2_btree_node_iter_end(node_iter) &&
 504             iter_current_key_modified &&
 505             b->c.level) {
 506                 struct bset_tree *t;
 507                 struct bkey_packed *k, *k2, *p;
 508
 509                 k = bch2_btree_node_iter_peek_all(node_iter, b);
 510
 511                 for_each_bset(b, t) {
 512                         bool set_pos = false;
 513
 514                         if (node_iter->data[0].end == t->end_offset)
 515                                 continue;
 516
 517                         k2 = bch2_btree_node_iter_bset_pos(node_iter, b, t);
 518
 519                         while ((p = bch2_bkey_prev_all(b, t, k2)) &&
 520                                bkey_iter_cmp(b, k, p) < 0) {
 521                                 k2 = p;
 522                                 set_pos = true;
 523                         }
 524
 525                         if (set_pos)
 526                                 btree_node_iter_set_set_pos(node_iter,
 527                                                             b, t, k2);
 528                 }
 529         }
 530 }
 531
 532 void bch2_btree_node_iter_fix(struct btree_trans *trans,
 533                               struct btree_path *path,
 534                               struct btree *b,
 535                               struct btree_node_iter *node_iter,
 536                               struct bkey_packed *where,
 537                               unsigned clobber_u64s,
 538                               unsigned new_u64s)
 539 {
 540         struct bset_tree *t = bch2_bkey_to_bset_inlined(b, where);
 541         struct btree_path *linked;
 542
 543         if (node_iter != &path->l[b->c.level].iter) {
 544                 __bch2_btree_node_iter_fix(path, b, node_iter, t,
 545                                            where, clobber_u64s, new_u64s);
 546
 547                 if (bch2_debug_check_iterators)
 548                         bch2_btree_node_iter_verify(node_iter, b);
 549         }
 550
 551         trans_for_each_path_with_node(trans, b, linked) {
 552                 __bch2_btree_node_iter_fix(linked, b,
 553                                            &linked->l[b->c.level].iter, t,
 554                                            where, clobber_u64s, new_u64s);
 555                 bch2_btree_path_verify_level(trans, linked, b->c.level);
 556         }
 557 }
 558
 559 /* Btree path level: pointer to a particular btree node and node iter */
 560
 561 static inline struct bkey_s_c __btree_iter_unpack(struct bch_fs *c,
 562                                                   struct btree_path_level *l,
 563                                                   struct bkey *u,
 564                                                   struct bkey_packed *k)
 565 {
 566         if (unlikely(!k)) {
 567                 /*
 568                  * signal to bch2_btree_iter_peek_slot() that we're currently at
 569                  * a hole
 570                  */
 571                 u->type = KEY_TYPE_deleted;
 572                 return bkey_s_c_null;
 573         }
 574
 575         return bkey_disassemble(l->b, k, u);
 576 }
 577
 578 static inline struct bkey_s_c btree_path_level_peek_all(struct bch_fs *c,
 579                                                         struct btree_path_level *l,
 580                                                         struct bkey *u)
 581 {
 582         return __btree_iter_unpack(c, l, u,
 583                         bch2_btree_node_iter_peek_all(&l->iter, l->b));
 584 }
 585
 586 static inline struct bkey_s_c btree_path_level_peek(struct btree_trans *trans,
 587                                                     struct btree_path *path,
 588                                                     struct btree_path_level *l,
 589                                                     struct bkey *u)
 590 {
 591         struct bkey_s_c k = __btree_iter_unpack(trans->c, l, u,
 592                         bch2_btree_node_iter_peek(&l->iter, l->b));
 593
 594         path->pos = k.k ? k.k->p : l->b->key.k.p;
 595         trans->paths_sorted = false;
 596         bch2_btree_path_verify_level(trans, path, l - path->l);
 597         return k;
 598 }
 599
 600 static inline struct bkey_s_c btree_path_level_prev(struct btree_trans *trans,
 601                                                     struct btree_path *path,
 602                                                     struct btree_path_level *l,
 603                                                     struct bkey *u)
 604 {
 605         struct bkey_s_c k = __btree_iter_unpack(trans->c, l, u,
 606                         bch2_btree_node_iter_prev(&l->iter, l->b));
 607
 608         path->pos = k.k ? k.k->p : l->b->data->min_key;
 609         trans->paths_sorted = false;
 610         bch2_btree_path_verify_level(trans, path, l - path->l);
 611         return k;
 612 }
 613
 614 static inline bool btree_path_advance_to_pos(struct btree_path *path,
 615                                              struct btree_path_level *l,
 616                                              int max_advance)
 617 {
 618         struct bkey_packed *k;
 619         int nr_advanced = 0;
 620
 621         while ((k = bch2_btree_node_iter_peek_all(&l->iter, l->b)) &&
 622                bkey_iter_pos_cmp(l->b, k, &path->pos) < 0) {
 623                 if (max_advance > 0 && nr_advanced >= max_advance)
 624                         return false;
 625
 626                 bch2_btree_node_iter_advance(&l->iter, l->b);
 627                 nr_advanced++;
 628         }
 629
 630         return true;
 631 }
 632
 633 static inline void __btree_path_level_init(struct btree_path *path,
 634                                            unsigned level)
 635 {
 636         struct btree_path_level *l = &path->l[level];
 637
 638         bch2_btree_node_iter_init(&l->iter, l->b, &path->pos);
 639
 640         /*
 641          * Iterators to interior nodes should always be pointed at the first non
 642          * whiteout:
 643          */
 644         if (level)
 645                 bch2_btree_node_iter_peek(&l->iter, l->b);
 646 }
 647
 648 void bch2_btree_path_level_init(struct btree_trans *trans,
 649                                 struct btree_path *path,
 650                                 struct btree *b)
 651 {
 652         BUG_ON(path->cached);
 653
 654         EBUG_ON(!btree_path_pos_in_node(path, b));
 655         EBUG_ON(b->c.lock.state.seq & 1);
 656
 657         path->l[b->c.level].lock_seq = b->c.lock.state.seq;
 658         path->l[b->c.level].b = b;
 659         __btree_path_level_init(path, b->c.level);
 660 }
 661
 662 /* Btree path: fixups after btree node updates: */
 663
 664 static void bch2_trans_revalidate_updates_in_node(struct btree_trans *trans, struct btree *b)
 665 {
 666         struct bch_fs *c = trans->c;
 667         struct btree_insert_entry *i;
 668
 669         trans_for_each_update(trans, i)
 670                 if (!i->cached &&
 671                     i->level    == b->c.level &&
 672                     i->btree_id == b->c.btree_id &&
 673                     bpos_cmp(i->k->k.p, b->data->min_key) >= 0 &&
 674                     bpos_cmp(i->k->k.p, b->data->max_key) <= 0) {
 675                         i->old_v = bch2_btree_path_peek_slot(i->path, &i->old_k).v;
 676
 677                         if (unlikely(trans->journal_replay_not_finished)) {
 678                                 struct bkey_i *j_k =
 679                                         bch2_journal_keys_peek_slot(c, i->btree_id, i->level,
 680                                                                     i->k->k.p);
 681
 682                                 if (j_k) {
 683                                         i->old_k = j_k->k;
 684                                         i->old_v = &j_k->v;
 685                                 }
 686                         }
 687                 }
 688 }
 689
 690 /*
 691  * A btree node is being replaced - update the iterator to point to the new
 692  * node:
 693  */
 694 void bch2_trans_node_add(struct btree_trans *trans, struct btree *b)
 695 {
 696         struct btree_path *path;
 697
 698         trans_for_each_path(trans, path)
 699                 if (path->uptodate == BTREE_ITER_UPTODATE &&
 700                     !path->cached &&
 701                     btree_path_pos_in_node(path, b)) {
 702                         enum btree_node_locked_type t =
 703                                 btree_lock_want(path, b->c.level);
 704
 705                         if (t != BTREE_NODE_UNLOCKED) {
 706                                 btree_node_unlock(trans, path, b->c.level);
 707                                 six_lock_increment(&b->c.lock, t);
 708                                 mark_btree_node_locked(trans, path, b->c.level, t);
 709                         }
 710
 711                         bch2_btree_path_level_init(trans, path, b);
 712                 }
 713
 714         bch2_trans_revalidate_updates_in_node(trans, b);
 715 }
 716
 717 /*
 718  * A btree node has been modified in such a way as to invalidate iterators - fix
 719  * them:
 720  */
 721 void bch2_trans_node_reinit_iter(struct btree_trans *trans, struct btree *b)
 722 {
 723         struct btree_path *path;
 724
 725         trans_for_each_path_with_node(trans, b, path)
 726                 __btree_path_level_init(path, b->c.level);
 727
 728         bch2_trans_revalidate_updates_in_node(trans, b);
 729 }
 730
 731 /* Btree path: traverse, set_pos: */
 732
 733 static inline int btree_path_lock_root(struct btree_trans *trans,
 734                                        struct btree_path *path,
 735                                        unsigned depth_want,
 736                                        unsigned long trace_ip)
 737 {
 738         struct bch_fs *c = trans->c;
 739         struct btree *b, **rootp = &c->btree_roots[path->btree_id].b;
 740         enum six_lock_type lock_type;
 741         unsigned i;
 742         int ret;
 743
 744         EBUG_ON(path->nodes_locked);
 745
 746         while (1) {
 747                 b = READ_ONCE(*rootp);
 748                 path->level = READ_ONCE(b->c.level);
 749
 750                 if (unlikely(path->level < depth_want)) {
 751                         /*
 752                          * the root is at a lower depth than the depth we want:
 753                          * got to the end of the btree, or we're walking nodes
 754                          * greater than some depth and there are no nodes >=
 755                          * that depth
 756                          */
 757                         path->level = depth_want;
 758                         for (i = path->level; i < BTREE_MAX_DEPTH; i++)
 759                                 path->l[i].b = NULL;
 760                         return 1;
 761                 }
 762
 763                 lock_type = __btree_lock_want(path, path->level);
 764                 ret = btree_node_lock(trans, path, &b->c,
 765                                       path->level, lock_type, trace_ip);
 766                 if (unlikely(ret)) {
 767                         if (bch2_err_matches(ret, BCH_ERR_lock_fail_root_changed))
 768                                 continue;
 769                         if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
 770                                 return ret;
 771                         BUG();
 772                 }
 773
 774                 if (likely(b == READ_ONCE(*rootp) &&
 775                            b->c.level == path->level &&
 776                            !race_fault())) {
 777                         for (i = 0; i < path->level; i++)
 778                                 path->l[i].b = ERR_PTR(-BCH_ERR_no_btree_node_lock_root);
 779                         path->l[path->level].b = b;
 780                         for (i = path->level + 1; i < BTREE_MAX_DEPTH; i++)
 781                                 path->l[i].b = NULL;
 782
 783                         mark_btree_node_locked(trans, path, path->level, lock_type);
 784                         bch2_btree_path_level_init(trans, path, b);
 785                         return 0;
 786                 }
 787
 788                 six_unlock_type(&b->c.lock, lock_type);
 789         }
 790 }
 791
 792 noinline
 793 static int btree_path_prefetch(struct btree_trans *trans, struct btree_path *path)
 794 {
 795         struct bch_fs *c = trans->c;
 796         struct btree_path_level *l = path_l(path);
 797         struct btree_node_iter node_iter = l->iter;
 798         struct bkey_packed *k;
 799         struct bkey_buf tmp;
 800         unsigned nr = test_bit(BCH_FS_STARTED, &c->flags)
 801                 ? (path->level > 1 ? 0 :  2)
 802                 : (path->level > 1 ? 1 : 16);
 803         bool was_locked = btree_node_locked(path, path->level);
 804         int ret = 0;
 805
 806         bch2_bkey_buf_init(&tmp);
 807
 808         while (nr-- && !ret) {
 809                 if (!bch2_btree_node_relock(trans, path, path->level))
 810                         break;
 811
 812                 bch2_btree_node_iter_advance(&node_iter, l->b);
 813                 k = bch2_btree_node_iter_peek(&node_iter, l->b);
 814                 if (!k)
 815                         break;
 816
 817                 bch2_bkey_buf_unpack(&tmp, c, l->b, k);
 818                 ret = bch2_btree_node_prefetch(c, trans, path, tmp.k, path->btree_id,
 819                                                path->level - 1);
 820         }
 821
 822         if (!was_locked)
 823                 btree_node_unlock(trans, path, path->level);
 824
 825         bch2_bkey_buf_exit(&tmp, c);
 826         return ret;
 827 }
 828
 829 static int btree_path_prefetch_j(struct btree_trans *trans, struct btree_path *path,
 830                                  struct btree_and_journal_iter *jiter)
 831 {
 832         struct bch_fs *c = trans->c;
 833         struct bkey_s_c k;
 834         struct bkey_buf tmp;
 835         unsigned nr = test_bit(BCH_FS_STARTED, &c->flags)
 836                 ? (path->level > 1 ? 0 :  2)
 837                 : (path->level > 1 ? 1 : 16);
 838         bool was_locked = btree_node_locked(path, path->level);
 839         int ret = 0;
 840
 841         bch2_bkey_buf_init(&tmp);
 842
 843         while (nr-- && !ret) {
 844                 if (!bch2_btree_node_relock(trans, path, path->level))
 845                         break;
 846
 847                 bch2_btree_and_journal_iter_advance(jiter);
 848                 k = bch2_btree_and_journal_iter_peek(jiter);
 849                 if (!k.k)
 850                         break;
 851
 852                 bch2_bkey_buf_reassemble(&tmp, c, k);
 853                 ret = bch2_btree_node_prefetch(c, trans, path, tmp.k, path->btree_id,
 854                                                path->level - 1);
 855         }
 856
 857         if (!was_locked)
 858                 btree_node_unlock(trans, path, path->level);
 859
 860         bch2_bkey_buf_exit(&tmp, c);
 861         return ret;
 862 }
 863
 864 static noinline void btree_node_mem_ptr_set(struct btree_trans *trans,
 865                                             struct btree_path *path,
 866                                             unsigned plevel, struct btree *b)
 867 {
 868         struct btree_path_level *l = &path->l[plevel];
 869         bool locked = btree_node_locked(path, plevel);
 870         struct bkey_packed *k;
 871         struct bch_btree_ptr_v2 *bp;
 872
 873         if (!bch2_btree_node_relock(trans, path, plevel))
 874                 return;
 875
 876         k = bch2_btree_node_iter_peek_all(&l->iter, l->b);
 877         BUG_ON(k->type != KEY_TYPE_btree_ptr_v2);
 878
 879         bp = (void *) bkeyp_val(&l->b->format, k);
 880         bp->mem_ptr = (unsigned long)b;
 881
 882         if (!locked)
 883                 btree_node_unlock(trans, path, plevel);
 884 }
 885
 886 static noinline int btree_node_iter_and_journal_peek(struct btree_trans *trans,
 887                                                      struct btree_path *path,
 888                                                      unsigned flags,
 889                                                      struct bkey_buf *out)
 890 {
 891         struct bch_fs *c = trans->c;
 892         struct btree_path_level *l = path_l(path);
 893         struct btree_and_journal_iter jiter;
 894         struct bkey_s_c k;
 895         int ret = 0;
 896
 897         __bch2_btree_and_journal_iter_init_node_iter(&jiter, c, l->b, l->iter, path->pos);
 898
 899         k = bch2_btree_and_journal_iter_peek(&jiter);
 900
 901         bch2_bkey_buf_reassemble(out, c, k);
 902
 903         if (flags & BTREE_ITER_PREFETCH)
 904                 ret = btree_path_prefetch_j(trans, path, &jiter);
 905
 906         bch2_btree_and_journal_iter_exit(&jiter);
 907         return ret;
 908 }
 909
 910 static __always_inline int btree_path_down(struct btree_trans *trans,
 911                                            struct btree_path *path,
 912                                            unsigned flags,
 913                                            unsigned long trace_ip)
 914 {
 915         struct bch_fs *c = trans->c;
 916         struct btree_path_level *l = path_l(path);
 917         struct btree *b;
 918         unsigned level = path->level - 1;
 919         enum six_lock_type lock_type = __btree_lock_want(path, level);
 920         struct bkey_buf tmp;
 921         int ret;
 922
 923         EBUG_ON(!btree_node_locked(path, path->level));
 924
 925         bch2_bkey_buf_init(&tmp);
 926
 927         if (unlikely(trans->journal_replay_not_finished)) {
 928                 ret = btree_node_iter_and_journal_peek(trans, path, flags, &tmp);
 929                 if (ret)
 930                         goto err;
 931         } else {
 932                 bch2_bkey_buf_unpack(&tmp, c, l->b,
 933                                  bch2_btree_node_iter_peek(&l->iter, l->b));
 934
 935                 if (flags & BTREE_ITER_PREFETCH) {
 936                         ret = btree_path_prefetch(trans, path);
 937                         if (ret)
 938                                 goto err;
 939                 }
 940         }
 941
 942         b = bch2_btree_node_get(trans, path, tmp.k, level, lock_type, trace_ip);
 943         ret = PTR_ERR_OR_ZERO(b);
 944         if (unlikely(ret))
 945                 goto err;
 946
 947         if (likely(!trans->journal_replay_not_finished &&
 948                    tmp.k->k.type == KEY_TYPE_btree_ptr_v2) &&
 949             unlikely(b != btree_node_mem_ptr(tmp.k)))
 950                 btree_node_mem_ptr_set(trans, path, level + 1, b);
 951
 952         if (btree_node_read_locked(path, level + 1))
 953                 btree_node_unlock(trans, path, level + 1);
 954
 955         mark_btree_node_locked(trans, path, level, lock_type);
 956         path->level = level;
 957         bch2_btree_path_level_init(trans, path, b);
 958
 959         bch2_btree_path_verify_locks(path);
 960 err:
 961         bch2_bkey_buf_exit(&tmp, c);
 962         return ret;
 963 }
 964
 965
 966 static int bch2_btree_path_traverse_all(struct btree_trans *trans)
 967 {
 968         struct bch_fs *c = trans->c;
 969         struct btree_path *path;
 970         unsigned long trace_ip = _RET_IP_;
 971         int i, ret = 0;
 972
 973         if (trans->in_traverse_all)
 974                 return -BCH_ERR_transaction_restart_in_traverse_all;
 975
 976         trans->in_traverse_all = true;
 977 retry_all:
 978         trans->restarted = 0;
 979
 980         trans_for_each_path(trans, path)
 981                 path->should_be_locked = false;
 982
 983         btree_trans_sort_paths(trans);
 984
 985         bch2_trans_unlock(trans);
 986         cond_resched();
 987
 988         if (unlikely(trans->memory_allocation_failure)) {
 989                 struct closure cl;
 990
 991                 closure_init_stack(&cl);
 992
 993                 do {
 994                         ret = bch2_btree_cache_cannibalize_lock(c, &cl);
 995                         closure_sync(&cl);
 996                 } while (ret);
 997         }
 998
 999         /* Now, redo traversals in correct order: */
1000         i = 0;
1001         while (i < trans->nr_sorted) {
1002                 path = trans->paths + trans->sorted[i];
1003
1004                 /*
1005                  * Traversing a path can cause another path to be added at about
1006                  * the same position:
1007                  */
1008                 if (path->uptodate) {
1009                         __btree_path_get(path, false);
1010                         ret = bch2_btree_path_traverse_one(trans, path, 0, _THIS_IP_);
1011                         __btree_path_put(path, false);
1012
1013                         if (bch2_err_matches(ret, BCH_ERR_transaction_restart) ||
1014                             ret == -ENOMEM)
1015                                 goto retry_all;
1016                         if (ret)
1017                                 goto err;
1018                 } else {
1019                         i++;
1020                 }
1021         }
1022
1023         /*
1024          * We used to assert that all paths had been traversed here
1025          * (path->uptodate < BTREE_ITER_NEED_TRAVERSE); however, since
1026          * path->Should_be_locked is not set yet, we we might have unlocked and
1027          * then failed to relock a path - that's fine.
1028          */
1029 err:
1030         bch2_btree_cache_cannibalize_unlock(c);
1031
1032         trans->in_traverse_all = false;
1033
1034         trace_and_count(c, trans_traverse_all, trans, trace_ip);
1035         return ret;
1036 }
1037
1038 static inline bool btree_path_check_pos_in_node(struct btree_path *path,
1039                                                 unsigned l, int check_pos)
1040 {
1041         if (check_pos < 0 && btree_path_pos_before_node(path, path->l[l].b))
1042                 return false;
1043         if (check_pos > 0 && btree_path_pos_after_node(path, path->l[l].b))
1044                 return false;
1045         return true;
1046 }
1047
1048 static inline bool btree_path_good_node(struct btree_trans *trans,
1049                                         struct btree_path *path,
1050                                         unsigned l, int check_pos)
1051 {
1052         return is_btree_node(path, l) &&
1053                 bch2_btree_node_relock(trans, path, l) &&
1054                 btree_path_check_pos_in_node(path, l, check_pos);
1055 }
1056
1057 static void btree_path_set_level_down(struct btree_trans *trans,
1058                                       struct btree_path *path,
1059                                       unsigned new_level)
1060 {
1061         unsigned l;
1062
1063         path->level = new_level;
1064
1065         for (l = path->level + 1; l < BTREE_MAX_DEPTH; l++)
1066                 if (btree_lock_want(path, l) == BTREE_NODE_UNLOCKED)
1067                         btree_node_unlock(trans, path, l);
1068
1069         btree_path_set_dirty(path, BTREE_ITER_NEED_TRAVERSE);
1070         bch2_btree_path_verify(trans, path);
1071 }
1072
1073 static noinline unsigned __btree_path_up_until_good_node(struct btree_trans *trans,
1074                                                          struct btree_path *path,
1075                                                          int check_pos)
1076 {
1077         unsigned i, l = path->level;
1078 again:
1079         while (btree_path_node(path, l) &&
1080                !btree_path_good_node(trans, path, l, check_pos))
1081                 __btree_path_set_level_up(trans, path, l++);
1082
1083         /* If we need intent locks, take them too: */
1084         for (i = l + 1;
1085              i < path->locks_want && btree_path_node(path, i);
1086              i++)
1087                 if (!bch2_btree_node_relock(trans, path, i)) {
1088                         while (l <= i)
1089                                 __btree_path_set_level_up(trans, path, l++);
1090                         goto again;
1091                 }
1092
1093         return l;
1094 }
1095
1096 static inline unsigned btree_path_up_until_good_node(struct btree_trans *trans,
1097                                                      struct btree_path *path,
1098                                                      int check_pos)
1099 {
1100         return likely(btree_node_locked(path, path->level) &&
1101                       btree_path_check_pos_in_node(path, path->level, check_pos))
1102                 ? path->level
1103                 : __btree_path_up_until_good_node(trans, path, check_pos);
1104 }
1105
1106 /*
1107  * This is the main state machine for walking down the btree - walks down to a
1108  * specified depth
1109  *
1110  * Returns 0 on success, -EIO on error (error reading in a btree node).
1111  *
1112  * On error, caller (peek_node()/peek_key()) must return NULL; the error is
1113  * stashed in the iterator and returned from bch2_trans_exit().
1114  */
1115 int bch2_btree_path_traverse_one(struct btree_trans *trans,
1116                                  struct btree_path *path,
1117                                  unsigned flags,
1118                                  unsigned long trace_ip)
1119 {
1120         unsigned depth_want = path->level;
1121         int ret = -((int) trans->restarted);
1122
1123         if (unlikely(ret))
1124                 goto out;
1125
1126         /*
1127          * Ensure we obey path->should_be_locked: if it's set, we can't unlock
1128          * and re-traverse the path without a transaction restart:
1129          */
1130         if (path->should_be_locked) {
1131                 ret = bch2_btree_path_relock(trans, path, trace_ip);
1132                 goto out;
1133         }
1134
1135         if (path->cached) {
1136                 ret = bch2_btree_path_traverse_cached(trans, path, flags);
1137                 goto out;
1138         }
1139
1140         if (unlikely(path->level >= BTREE_MAX_DEPTH))
1141                 goto out;
1142
1143         path->level = btree_path_up_until_good_node(trans, path, 0);
1144
1145         EBUG_ON(btree_path_node(path, path->level) &&
1146                 !btree_node_locked(path, path->level));
1147
1148         /*
1149          * Note: path->nodes[path->level] may be temporarily NULL here - that
1150          * would indicate to other code that we got to the end of the btree,
1151          * here it indicates that relocking the root failed - it's critical that
1152          * btree_path_lock_root() comes next and that it can't fail
1153          */
1154         while (path->level > depth_want) {
1155                 ret = btree_path_node(path, path->level)
1156                         ? btree_path_down(trans, path, flags, trace_ip)
1157                         : btree_path_lock_root(trans, path, depth_want, trace_ip);
1158                 if (unlikely(ret)) {
1159                         if (ret == 1) {
1160                                 /*
1161                                  * No nodes at this level - got to the end of
1162                                  * the btree:
1163                                  */
1164                                 ret = 0;
1165                                 goto out;
1166                         }
1167
1168                         __bch2_btree_path_unlock(trans, path);
1169                         path->level = depth_want;
1170                         path->l[path->level].b = ERR_PTR(ret);
1171                         goto out;
1172                 }
1173         }
1174
1175         path->uptodate = BTREE_ITER_UPTODATE;
1176 out:
1177         if (bch2_err_matches(ret, BCH_ERR_transaction_restart) != !!trans->restarted) {
1178                 struct printbuf buf = PRINTBUF;
1179
1180                 prt_printf(&buf, "ret %s (%i) trans->restarted %s (%i)\n",
1181                            bch2_err_str(ret), ret,
1182                            bch2_err_str(trans->restarted), trans->restarted);
1183 #ifdef CONFIG_BCACHEFS_DEBUG
1184                 bch2_prt_backtrace(&buf, &trans->last_restarted);
1185 #endif
1186                 panic("%s", buf.buf);
1187         }
1188         bch2_btree_path_verify(trans, path);
1189         return ret;
1190 }
1191
1192 static inline void btree_path_copy(struct btree_trans *trans, struct btree_path *dst,
1193                             struct btree_path *src)
1194 {
1195         unsigned i, offset = offsetof(struct btree_path, pos);
1196
1197         memcpy((void *) dst + offset,
1198                (void *) src + offset,
1199                sizeof(struct btree_path) - offset);
1200
1201         for (i = 0; i < BTREE_MAX_DEPTH; i++) {
1202                 unsigned t = btree_node_locked_type(dst, i);
1203
1204                 if (t != BTREE_NODE_UNLOCKED)
1205                         six_lock_increment(&dst->l[i].b->c.lock, t);
1206         }
1207 }
1208
1209 static struct btree_path *btree_path_clone(struct btree_trans *trans, struct btree_path *src,
1210                                            bool intent)
1211 {
1212         struct btree_path *new = btree_path_alloc(trans, src);
1213
1214         btree_path_copy(trans, new, src);
1215         __btree_path_get(new, intent);
1216         return new;
1217 }
1218
1219 __flatten
1220 struct btree_path *__bch2_btree_path_make_mut(struct btree_trans *trans,
1221                          struct btree_path *path, bool intent,
1222                          unsigned long ip)
1223 {
1224         __btree_path_put(path, intent);
1225         path = btree_path_clone(trans, path, intent);
1226         path->preserve = false;
1227         return path;
1228 }
1229
1230 struct btree_path * __must_check
1231 __bch2_btree_path_set_pos(struct btree_trans *trans,
1232                    struct btree_path *path, struct bpos new_pos,
1233                    bool intent, unsigned long ip, int cmp)
1234 {
1235         unsigned level = path->level;
1236
1237         bch2_trans_verify_not_in_restart(trans);
1238         EBUG_ON(!path->ref);
1239
1240         path = bch2_btree_path_make_mut(trans, path, intent, ip);
1241
1242         path->pos               = new_pos;
1243         trans->paths_sorted     = false;
1244
1245         if (unlikely(path->cached)) {
1246                 btree_node_unlock(trans, path, 0);
1247                 path->l[0].b = ERR_PTR(-BCH_ERR_no_btree_node_up);
1248                 btree_path_set_dirty(path, BTREE_ITER_NEED_TRAVERSE);
1249                 goto out;
1250         }
1251
1252         level = btree_path_up_until_good_node(trans, path, cmp);
1253
1254         if (btree_path_node(path, level)) {
1255                 struct btree_path_level *l = &path->l[level];
1256
1257                 BUG_ON(!btree_node_locked(path, level));
1258                 /*
1259                  * We might have to skip over many keys, or just a few: try
1260                  * advancing the node iterator, and if we have to skip over too
1261                  * many keys just reinit it (or if we're rewinding, since that
1262                  * is expensive).
1263                  */
1264                 if (cmp < 0 ||
1265                     !btree_path_advance_to_pos(path, l, 8))
1266                         bch2_btree_node_iter_init(&l->iter, l->b, &path->pos);
1267
1268                 /*
1269                  * Iterators to interior nodes should always be pointed at the first non
1270                  * whiteout:
1271                  */
1272                 if (unlikely(level))
1273                         bch2_btree_node_iter_peek(&l->iter, l->b);
1274         }
1275
1276         if (unlikely(level != path->level)) {
1277                 btree_path_set_dirty(path, BTREE_ITER_NEED_TRAVERSE);
1278                 __bch2_btree_path_unlock(trans, path);
1279         }
1280 out:
1281         bch2_btree_path_verify(trans, path);
1282         return path;
1283 }
1284
1285 /* Btree path: main interface: */
1286
1287 static struct btree_path *have_path_at_pos(struct btree_trans *trans, struct btree_path *path)
1288 {
1289         struct btree_path *sib;
1290
1291         sib = prev_btree_path(trans, path);
1292         if (sib && !btree_path_cmp(sib, path))
1293                 return sib;
1294
1295         sib = next_btree_path(trans, path);
1296         if (sib && !btree_path_cmp(sib, path))
1297                 return sib;
1298
1299         return NULL;
1300 }
1301
1302 static struct btree_path *have_node_at_pos(struct btree_trans *trans, struct btree_path *path)
1303 {
1304         struct btree_path *sib;
1305
1306         sib = prev_btree_path(trans, path);
1307         if (sib && sib->level == path->level && path_l(sib)->b == path_l(path)->b)
1308                 return sib;
1309
1310         sib = next_btree_path(trans, path);
1311         if (sib && sib->level == path->level && path_l(sib)->b == path_l(path)->b)
1312                 return sib;
1313
1314         return NULL;
1315 }
1316
1317 static inline void __bch2_path_free(struct btree_trans *trans, struct btree_path *path)
1318 {
1319         __bch2_btree_path_unlock(trans, path);
1320         btree_path_list_remove(trans, path);
1321         trans->paths_allocated &= ~(1ULL << path->idx);
1322 }
1323
1324 void bch2_path_put(struct btree_trans *trans, struct btree_path *path, bool intent)
1325 {
1326         struct btree_path *dup;
1327
1328         EBUG_ON(trans->paths + path->idx != path);
1329         EBUG_ON(!path->ref);
1330
1331         if (!__btree_path_put(path, intent))
1332                 return;
1333
1334         dup = path->preserve
1335                 ? have_path_at_pos(trans, path)
1336                 : have_node_at_pos(trans, path);
1337
1338         if (!dup && !(!path->preserve && !is_btree_node(path, path->level)))
1339                 return;
1340
1341         if (path->should_be_locked &&
1342             !trans->restarted &&
1343             (!dup || !bch2_btree_path_relock_norestart(trans, dup, _THIS_IP_)))
1344                 return;
1345
1346         if (dup) {
1347                 dup->preserve           |= path->preserve;
1348                 dup->should_be_locked   |= path->should_be_locked;
1349         }
1350
1351         __bch2_path_free(trans, path);
1352 }
1353
1354 static void bch2_path_put_nokeep(struct btree_trans *trans, struct btree_path *path,
1355                                  bool intent)
1356 {
1357         EBUG_ON(trans->paths + path->idx != path);
1358         EBUG_ON(!path->ref);
1359
1360         if (!__btree_path_put(path, intent))
1361                 return;
1362
1363         __bch2_path_free(trans, path);
1364 }
1365
1366 void bch2_trans_restart_error(struct btree_trans *trans, u32 restart_count)
1367 {
1368         panic("trans->restart_count %u, should be %u, last restarted by %pS\n",
1369               trans->restart_count, restart_count,
1370               (void *) trans->last_begin_ip);
1371 }
1372
1373 void bch2_trans_in_restart_error(struct btree_trans *trans)
1374 {
1375         panic("in transaction restart: %s, last restarted by %pS\n",
1376               bch2_err_str(trans->restarted),
1377               (void *) trans->last_begin_ip);
1378 }
1379
1380 noinline __cold
1381 void bch2_trans_updates_to_text(struct printbuf *buf, struct btree_trans *trans)
1382 {
1383         struct btree_insert_entry *i;
1384         struct btree_write_buffered_key *wb;
1385
1386         prt_printf(buf, "transaction updates for %s journal seq %llu",
1387                trans->fn, trans->journal_res.seq);
1388         prt_newline(buf);
1389         printbuf_indent_add(buf, 2);
1390
1391         trans_for_each_update(trans, i) {
1392                 struct bkey_s_c old = { &i->old_k, i->old_v };
1393
1394                 prt_printf(buf, "update: btree=%s cached=%u %pS",
1395                        bch2_btree_ids[i->btree_id],
1396                        i->cached,
1397                        (void *) i->ip_allocated);
1398                 prt_newline(buf);
1399
1400                 prt_printf(buf, "  old ");
1401                 bch2_bkey_val_to_text(buf, trans->c, old);
1402                 prt_newline(buf);
1403
1404                 prt_printf(buf, "  new ");
1405                 bch2_bkey_val_to_text(buf, trans->c, bkey_i_to_s_c(i->k));
1406                 prt_newline(buf);
1407         }
1408
1409         trans_for_each_wb_update(trans, wb) {
1410                 prt_printf(buf, "update: btree=%s wb=1 %pS",
1411                        bch2_btree_ids[wb->btree],
1412                        (void *) i->ip_allocated);
1413                 prt_newline(buf);
1414
1415                 prt_printf(buf, "  new ");
1416                 bch2_bkey_val_to_text(buf, trans->c, bkey_i_to_s_c(&wb->k));
1417                 prt_newline(buf);
1418         }
1419
1420         printbuf_indent_sub(buf, 2);
1421 }
1422
1423 noinline __cold
1424 void bch2_dump_trans_updates(struct btree_trans *trans)
1425 {
1426         struct printbuf buf = PRINTBUF;
1427
1428         bch2_trans_updates_to_text(&buf, trans);
1429         bch2_print_string_as_lines(KERN_ERR, buf.buf);
1430         printbuf_exit(&buf);
1431 }
1432
1433 noinline __cold
1434 void bch2_btree_path_to_text(struct printbuf *out, struct btree_path *path)
1435 {
1436         prt_printf(out, "path: idx %2u ref %u:%u %c %c btree=%s l=%u pos ",
1437                    path->idx, path->ref, path->intent_ref,
1438                    path->preserve ? 'P' : ' ',
1439                    path->should_be_locked ? 'S' : ' ',
1440                    bch2_btree_ids[path->btree_id],
1441                    path->level);
1442         bch2_bpos_to_text(out, path->pos);
1443
1444         prt_printf(out, " locks %u", path->nodes_locked);
1445 #ifdef TRACK_PATH_ALLOCATED
1446         prt_printf(out, " %pS", (void *) path->ip_allocated);
1447 #endif
1448         prt_newline(out);
1449 }
1450
1451 noinline __cold
1452 void __bch2_trans_paths_to_text(struct printbuf *out, struct btree_trans *trans,
1453                                 bool nosort)
1454 {
1455         struct btree_path *path;
1456         unsigned idx;
1457
1458         if (!nosort)
1459                 btree_trans_sort_paths(trans);
1460
1461         trans_for_each_path_inorder(trans, path, idx)
1462                 bch2_btree_path_to_text(out, path);
1463 }
1464
1465 noinline __cold
1466 void bch2_trans_paths_to_text(struct printbuf *out, struct btree_trans *trans)
1467 {
1468         __bch2_trans_paths_to_text(out, trans, false);
1469 }
1470
1471 noinline __cold
1472 void __bch2_dump_trans_paths_updates(struct btree_trans *trans, bool nosort)
1473 {
1474         struct printbuf buf = PRINTBUF;
1475
1476         __bch2_trans_paths_to_text(&buf, trans, nosort);
1477         bch2_trans_updates_to_text(&buf, trans);
1478
1479         bch2_print_string_as_lines(KERN_ERR, buf.buf);
1480         printbuf_exit(&buf);
1481 }
1482
1483 noinline __cold
1484 void bch2_dump_trans_paths_updates(struct btree_trans *trans)
1485 {
1486         __bch2_dump_trans_paths_updates(trans, false);
1487 }
1488
1489 noinline __cold
1490 static void bch2_trans_update_max_paths(struct btree_trans *trans)
1491 {
1492         struct btree_transaction_stats *s = btree_trans_stats(trans);
1493         struct printbuf buf = PRINTBUF;
1494
1495         if (!s)
1496                 return;
1497
1498         bch2_trans_paths_to_text(&buf, trans);
1499
1500         if (!buf.allocation_failure) {
1501                 mutex_lock(&s->lock);
1502                 if (s->nr_max_paths < hweight64(trans->paths_allocated)) {
1503                         s->nr_max_paths = trans->nr_max_paths =
1504                                 hweight64(trans->paths_allocated);
1505                         swap(s->max_paths_text, buf.buf);
1506                 }
1507                 mutex_unlock(&s->lock);
1508         }
1509
1510         printbuf_exit(&buf);
1511
1512         trans->nr_max_paths = hweight64(trans->paths_allocated);
1513 }
1514
1515 static noinline void btree_path_overflow(struct btree_trans *trans)
1516 {
1517         bch2_dump_trans_paths_updates(trans);
1518         panic("trans path oveflow\n");
1519 }
1520
1521 static inline struct btree_path *btree_path_alloc(struct btree_trans *trans,
1522                                                   struct btree_path *pos)
1523 {
1524         struct btree_path *path;
1525         unsigned idx;
1526
1527         if (unlikely(trans->paths_allocated ==
1528                      ~((~0ULL << 1) << (BTREE_ITER_MAX - 1))))
1529                 btree_path_overflow(trans);
1530
1531         idx = __ffs64(~trans->paths_allocated);
1532
1533         /*
1534          * Do this before marking the new path as allocated, since it won't be
1535          * initialized yet:
1536          */
1537         if (unlikely(idx > trans->nr_max_paths))
1538                 bch2_trans_update_max_paths(trans);
1539
1540         trans->paths_allocated |= 1ULL << idx;
1541
1542         path = &trans->paths[idx];
1543         path->idx               = idx;
1544         path->ref               = 0;
1545         path->intent_ref        = 0;
1546         path->nodes_locked      = 0;
1547
1548         btree_path_list_add(trans, pos, path);
1549         trans->paths_sorted = false;
1550         return path;
1551 }
1552
1553 struct btree_path *bch2_path_get(struct btree_trans *trans,
1554                                  enum btree_id btree_id, struct bpos pos,
1555                                  unsigned locks_want, unsigned level,
1556                                  unsigned flags, unsigned long ip)
1557 {
1558         struct btree_path *path, *path_pos = NULL;
1559         bool cached = flags & BTREE_ITER_CACHED;
1560         bool intent = flags & BTREE_ITER_INTENT;
1561         int i;
1562
1563         bch2_trans_verify_not_in_restart(trans);
1564         bch2_trans_verify_locks(trans);
1565
1566         btree_trans_sort_paths(trans);
1567
1568         trans_for_each_path_inorder(trans, path, i) {
1569                 if (__btree_path_cmp(path,
1570                                      btree_id,
1571                                      cached,
1572                                      pos,
1573                                      level) > 0)
1574                         break;
1575
1576                 path_pos = path;
1577         }
1578
1579         if (path_pos &&
1580             path_pos->cached    == cached &&
1581             path_pos->btree_id  == btree_id &&
1582             path_pos->level     == level) {
1583                 __btree_path_get(path_pos, intent);
1584                 path = bch2_btree_path_set_pos(trans, path_pos, pos, intent, ip);
1585         } else {
1586                 path = btree_path_alloc(trans, path_pos);
1587                 path_pos = NULL;
1588
1589                 __btree_path_get(path, intent);
1590                 path->pos                       = pos;
1591                 path->btree_id                  = btree_id;
1592                 path->cached                    = cached;
1593                 path->uptodate                  = BTREE_ITER_NEED_TRAVERSE;
1594                 path->should_be_locked          = false;
1595                 path->level                     = level;
1596                 path->locks_want                = locks_want;
1597                 path->nodes_locked              = 0;
1598                 for (i = 0; i < ARRAY_SIZE(path->l); i++)
1599                         path->l[i].b            = ERR_PTR(-BCH_ERR_no_btree_node_init);
1600 #ifdef TRACK_PATH_ALLOCATED
1601                 path->ip_allocated              = ip;
1602 #endif
1603                 trans->paths_sorted             = false;
1604         }
1605
1606         if (!(flags & BTREE_ITER_NOPRESERVE))
1607                 path->preserve = true;
1608
1609         if (path->intent_ref)
1610                 locks_want = max(locks_want, level + 1);
1611
1612         /*
1613          * If the path has locks_want greater than requested, we don't downgrade
1614          * it here - on transaction restart because btree node split needs to
1615          * upgrade locks, we might be putting/getting the iterator again.
1616          * Downgrading iterators only happens via bch2_trans_downgrade(), after
1617          * a successful transaction commit.
1618          */
1619
1620         locks_want = min(locks_want, BTREE_MAX_DEPTH);
1621         if (locks_want > path->locks_want)
1622                 bch2_btree_path_upgrade_noupgrade_sibs(trans, path, locks_want);
1623
1624         return path;
1625 }
1626
1627 struct bkey_s_c bch2_btree_path_peek_slot(struct btree_path *path, struct bkey *u)
1628 {
1629
1630         struct btree_path_level *l = path_l(path);
1631         struct bkey_packed *_k;
1632         struct bkey_s_c k;
1633
1634         if (unlikely(!l->b))
1635                 return bkey_s_c_null;
1636
1637         EBUG_ON(path->uptodate != BTREE_ITER_UPTODATE);
1638         EBUG_ON(!btree_node_locked(path, path->level));
1639
1640         if (!path->cached) {
1641                 _k = bch2_btree_node_iter_peek_all(&l->iter, l->b);
1642                 k = _k ? bkey_disassemble(l->b, _k, u) : bkey_s_c_null;
1643
1644                 EBUG_ON(k.k && bkey_deleted(k.k) && bpos_eq(k.k->p, path->pos));
1645
1646                 if (!k.k || !bpos_eq(path->pos, k.k->p))
1647                         goto hole;
1648         } else {
1649                 struct bkey_cached *ck = (void *) path->l[0].b;
1650
1651                 EBUG_ON(ck &&
1652                         (path->btree_id != ck->key.btree_id ||
1653                          !bkey_eq(path->pos, ck->key.pos)));
1654                 if (!ck || !ck->valid)
1655                         return bkey_s_c_null;
1656
1657                 *u = ck->k->k;
1658                 k = bkey_i_to_s_c(ck->k);
1659         }
1660
1661         return k;
1662 hole:
1663         bkey_init(u);
1664         u->p = path->pos;
1665         return (struct bkey_s_c) { u, NULL };
1666 }
1667
1668 /* Btree iterators: */
1669
1670 int __must_check
1671 __bch2_btree_iter_traverse(struct btree_iter *iter)
1672 {
1673         return bch2_btree_path_traverse(iter->trans, iter->path, iter->flags);
1674 }
1675
1676 int __must_check
1677 bch2_btree_iter_traverse(struct btree_iter *iter)
1678 {
1679         int ret;
1680
1681         iter->path = bch2_btree_path_set_pos(iter->trans, iter->path,
1682                                         btree_iter_search_key(iter),
1683                                         iter->flags & BTREE_ITER_INTENT,
1684                                         btree_iter_ip_allocated(iter));
1685
1686         ret = bch2_btree_path_traverse(iter->trans, iter->path, iter->flags);
1687         if (ret)
1688                 return ret;
1689
1690         btree_path_set_should_be_locked(iter->path);
1691         return 0;
1692 }
1693
1694 /* Iterate across nodes (leaf and interior nodes) */
1695
1696 struct btree *bch2_btree_iter_peek_node(struct btree_iter *iter)
1697 {
1698         struct btree_trans *trans = iter->trans;
1699         struct btree *b = NULL;
1700         int ret;
1701
1702         EBUG_ON(iter->path->cached);
1703         bch2_btree_iter_verify(iter);
1704
1705         ret = bch2_btree_path_traverse(trans, iter->path, iter->flags);
1706         if (ret)
1707                 goto err;
1708
1709         b = btree_path_node(iter->path, iter->path->level);
1710         if (!b)
1711                 goto out;
1712
1713         BUG_ON(bpos_lt(b->key.k.p, iter->pos));
1714
1715         bkey_init(&iter->k);
1716         iter->k.p = iter->pos = b->key.k.p;
1717
1718         iter->path = bch2_btree_path_set_pos(trans, iter->path, b->key.k.p,
1719                                         iter->flags & BTREE_ITER_INTENT,
1720                                         btree_iter_ip_allocated(iter));
1721         btree_path_set_should_be_locked(iter->path);
1722 out:
1723         bch2_btree_iter_verify_entry_exit(iter);
1724         bch2_btree_iter_verify(iter);
1725
1726         return b;
1727 err:
1728         b = ERR_PTR(ret);
1729         goto out;
1730 }
1731
1732 struct btree *bch2_btree_iter_next_node(struct btree_iter *iter)
1733 {
1734         struct btree_trans *trans = iter->trans;
1735         struct btree_path *path = iter->path;
1736         struct btree *b = NULL;
1737         int ret;
1738
1739         bch2_trans_verify_not_in_restart(trans);
1740         EBUG_ON(iter->path->cached);
1741         bch2_btree_iter_verify(iter);
1742
1743         /* already at end? */
1744         if (!btree_path_node(path, path->level))
1745                 return NULL;
1746
1747         /* got to end? */
1748         if (!btree_path_node(path, path->level + 1)) {
1749                 btree_path_set_level_up(trans, path);
1750                 return NULL;
1751         }
1752
1753         if (!bch2_btree_node_relock(trans, path, path->level + 1)) {
1754                 __bch2_btree_path_unlock(trans, path);
1755                 path->l[path->level].b          = ERR_PTR(-BCH_ERR_no_btree_node_relock);
1756                 path->l[path->level + 1].b      = ERR_PTR(-BCH_ERR_no_btree_node_relock);
1757                 btree_path_set_dirty(path, BTREE_ITER_NEED_TRAVERSE);
1758                 trace_and_count(trans->c, trans_restart_relock_next_node, trans, _THIS_IP_, path);
1759                 ret = btree_trans_restart(trans, BCH_ERR_transaction_restart_relock);
1760                 goto err;
1761         }
1762
1763         b = btree_path_node(path, path->level + 1);
1764
1765         if (bpos_eq(iter->pos, b->key.k.p)) {
1766                 __btree_path_set_level_up(trans, path, path->level++);
1767         } else {
1768                 /*
1769                  * Haven't gotten to the end of the parent node: go back down to
1770                  * the next child node
1771                  */
1772                 path = iter->path =
1773                         bch2_btree_path_set_pos(trans, path, bpos_successor(iter->pos),
1774                                            iter->flags & BTREE_ITER_INTENT,
1775                                            btree_iter_ip_allocated(iter));
1776
1777                 btree_path_set_level_down(trans, path, iter->min_depth);
1778
1779                 ret = bch2_btree_path_traverse(trans, path, iter->flags);
1780                 if (ret)
1781                         goto err;
1782
1783                 b = path->l[path->level].b;
1784         }
1785
1786         bkey_init(&iter->k);
1787         iter->k.p = iter->pos = b->key.k.p;
1788
1789         iter->path = bch2_btree_path_set_pos(trans, iter->path, b->key.k.p,
1790                                         iter->flags & BTREE_ITER_INTENT,
1791                                         btree_iter_ip_allocated(iter));
1792         btree_path_set_should_be_locked(iter->path);
1793         BUG_ON(iter->path->uptodate);
1794 out:
1795         bch2_btree_iter_verify_entry_exit(iter);
1796         bch2_btree_iter_verify(iter);
1797
1798         return b;
1799 err:
1800         b = ERR_PTR(ret);
1801         goto out;
1802 }
1803
1804 /* Iterate across keys (in leaf nodes only) */
1805
1806 inline bool bch2_btree_iter_advance(struct btree_iter *iter)
1807 {
1808         if (likely(!(iter->flags & BTREE_ITER_ALL_LEVELS))) {
1809                 struct bpos pos = iter->k.p;
1810                 bool ret = !(iter->flags & BTREE_ITER_ALL_SNAPSHOTS
1811                              ? bpos_eq(pos, SPOS_MAX)
1812                              : bkey_eq(pos, SPOS_MAX));
1813
1814                 if (ret && !(iter->flags & BTREE_ITER_IS_EXTENTS))
1815                         pos = bkey_successor(iter, pos);
1816                 bch2_btree_iter_set_pos(iter, pos);
1817                 return ret;
1818         } else {
1819                 if (!btree_path_node(iter->path, iter->path->level))
1820                         return true;
1821
1822                 iter->advanced = true;
1823                 return false;
1824         }
1825 }
1826
1827 inline bool bch2_btree_iter_rewind(struct btree_iter *iter)
1828 {
1829         struct bpos pos = bkey_start_pos(&iter->k);
1830         bool ret = !(iter->flags & BTREE_ITER_ALL_SNAPSHOTS
1831                      ? bpos_eq(pos, POS_MIN)
1832                      : bkey_eq(pos, POS_MIN));
1833
1834         if (ret && !(iter->flags & BTREE_ITER_IS_EXTENTS))
1835                 pos = bkey_predecessor(iter, pos);
1836         bch2_btree_iter_set_pos(iter, pos);
1837         return ret;
1838 }
1839
1840 static noinline
1841 struct bkey_i *__bch2_btree_trans_peek_updates(struct btree_iter *iter)
1842 {
1843         struct btree_insert_entry *i;
1844         struct bkey_i *ret = NULL;
1845
1846         trans_for_each_update(iter->trans, i) {
1847                 if (i->btree_id < iter->btree_id)
1848                         continue;
1849                 if (i->btree_id > iter->btree_id)
1850                         break;
1851                 if (bpos_lt(i->k->k.p, iter->path->pos))
1852                         continue;
1853                 if (i->key_cache_already_flushed)
1854                         continue;
1855                 if (!ret || bpos_lt(i->k->k.p, ret->k.p))
1856                         ret = i->k;
1857         }
1858
1859         return ret;
1860 }
1861
1862 static inline struct bkey_i *btree_trans_peek_updates(struct btree_iter *iter)
1863 {
1864         return iter->flags & BTREE_ITER_WITH_UPDATES
1865                 ? __bch2_btree_trans_peek_updates(iter)
1866                 : NULL;
1867 }
1868
1869 struct bkey_i *bch2_btree_journal_peek(struct btree_trans *trans,
1870                                        struct btree_iter *iter,
1871                                        struct bpos end_pos)
1872 {
1873         struct bkey_i *k;
1874
1875         if (bpos_lt(iter->path->pos, iter->journal_pos))
1876                 iter->journal_idx = 0;
1877
1878         k = bch2_journal_keys_peek_upto(trans->c, iter->btree_id,
1879                                         iter->path->level,
1880                                         iter->path->pos,
1881                                         end_pos,
1882                                         &iter->journal_idx);
1883
1884         iter->journal_pos = k ? k->k.p : end_pos;
1885         return k;
1886 }
1887
1888 static noinline
1889 struct bkey_s_c btree_trans_peek_slot_journal(struct btree_trans *trans,
1890                                               struct btree_iter *iter)
1891 {
1892         struct bkey_i *k = bch2_btree_journal_peek(trans, iter, iter->path->pos);
1893
1894         if (k) {
1895                 iter->k = k->k;
1896                 return bkey_i_to_s_c(k);
1897         } else {
1898                 return bkey_s_c_null;
1899         }
1900 }
1901
1902 static noinline
1903 struct bkey_s_c btree_trans_peek_journal(struct btree_trans *trans,
1904                                          struct btree_iter *iter,
1905                                          struct bkey_s_c k)
1906 {
1907         struct bkey_i *next_journal =
1908                 bch2_btree_journal_peek(trans, iter,
1909                                 k.k ? k.k->p : path_l(iter->path)->b->key.k.p);
1910
1911         if (next_journal) {
1912                 iter->k = next_journal->k;
1913                 k = bkey_i_to_s_c(next_journal);
1914         }
1915
1916         return k;
1917 }
1918
1919 /*
1920  * Checks btree key cache for key at iter->pos and returns it if present, or
1921  * bkey_s_c_null:
1922  */
1923 static noinline
1924 struct bkey_s_c btree_trans_peek_key_cache(struct btree_iter *iter, struct bpos pos)
1925 {
1926         struct btree_trans *trans = iter->trans;
1927         struct bch_fs *c = trans->c;
1928         struct bkey u;
1929         struct bkey_s_c k;
1930         int ret;
1931
1932         if ((iter->flags & BTREE_ITER_KEY_CACHE_FILL) &&
1933             bpos_eq(iter->pos, pos))
1934                 return bkey_s_c_null;
1935
1936         if (!bch2_btree_key_cache_find(c, iter->btree_id, pos))
1937                 return bkey_s_c_null;
1938
1939         if (!iter->key_cache_path)
1940                 iter->key_cache_path = bch2_path_get(trans, iter->btree_id, pos,
1941                                                      iter->flags & BTREE_ITER_INTENT, 0,
1942                                                      iter->flags|BTREE_ITER_CACHED|
1943                                                      BTREE_ITER_CACHED_NOFILL,
1944                                                      _THIS_IP_);
1945
1946         iter->key_cache_path = bch2_btree_path_set_pos(trans, iter->key_cache_path, pos,
1947                                         iter->flags & BTREE_ITER_INTENT,
1948                                         btree_iter_ip_allocated(iter));
1949
1950         ret =   bch2_btree_path_traverse(trans, iter->key_cache_path,
1951                                          iter->flags|BTREE_ITER_CACHED) ?:
1952                 bch2_btree_path_relock(trans, iter->path, _THIS_IP_);
1953         if (unlikely(ret))
1954                 return bkey_s_c_err(ret);
1955
1956         btree_path_set_should_be_locked(iter->key_cache_path);
1957
1958         k = bch2_btree_path_peek_slot(iter->key_cache_path, &u);
1959         if (k.k && !bkey_err(k)) {
1960                 iter->k = u;
1961                 k.k = &iter->k;
1962         }
1963         return k;
1964 }
1965
1966 static struct bkey_s_c __bch2_btree_iter_peek(struct btree_iter *iter, struct bpos search_key)
1967 {
1968         struct btree_trans *trans = iter->trans;
1969         struct bkey_i *next_update;
1970         struct bkey_s_c k, k2;
1971         int ret;
1972
1973         EBUG_ON(iter->path->cached);
1974         bch2_btree_iter_verify(iter);
1975
1976         while (1) {
1977                 struct btree_path_level *l;
1978
1979                 iter->path = bch2_btree_path_set_pos(trans, iter->path, search_key,
1980                                         iter->flags & BTREE_ITER_INTENT,
1981                                         btree_iter_ip_allocated(iter));
1982
1983                 ret = bch2_btree_path_traverse(trans, iter->path, iter->flags);
1984                 if (unlikely(ret)) {
1985                         /* ensure that iter->k is consistent with iter->pos: */
1986                         bch2_btree_iter_set_pos(iter, iter->pos);
1987                         k = bkey_s_c_err(ret);
1988                         goto out;
1989                 }
1990
1991                 l = path_l(iter->path);
1992
1993                 if (unlikely(!l->b)) {
1994                         /* No btree nodes at requested level: */
1995                         bch2_btree_iter_set_pos(iter, SPOS_MAX);
1996                         k = bkey_s_c_null;
1997                         goto out;
1998                 }
1999
2000                 btree_path_set_should_be_locked(iter->path);
2001
2002                 k = btree_path_level_peek_all(trans->c, l, &iter->k);
2003
2004                 if (unlikely(iter->flags & BTREE_ITER_WITH_KEY_CACHE) &&
2005                     k.k &&
2006                     (k2 = btree_trans_peek_key_cache(iter, k.k->p)).k) {
2007                         k = k2;
2008                         ret = bkey_err(k);
2009                         if (ret) {
2010                                 bch2_btree_iter_set_pos(iter, iter->pos);
2011                                 goto out;
2012                         }
2013                 }
2014
2015                 if (unlikely(iter->flags & BTREE_ITER_WITH_JOURNAL))
2016                         k = btree_trans_peek_journal(trans, iter, k);
2017
2018                 next_update = btree_trans_peek_updates(iter);
2019
2020                 if (next_update &&
2021                     bpos_le(next_update->k.p,
2022                             k.k ? k.k->p : l->b->key.k.p)) {
2023                         iter->k = next_update->k;
2024                         k = bkey_i_to_s_c(next_update);
2025                 }
2026
2027                 if (k.k && bkey_deleted(k.k)) {
2028                         /*
2029                          * If we've got a whiteout, and it's after the search
2030                          * key, advance the search key to the whiteout instead
2031                          * of just after the whiteout - it might be a btree
2032                          * whiteout, with a real key at the same position, since
2033                          * in the btree deleted keys sort before non deleted.
2034                          */
2035                         search_key = !bpos_eq(search_key, k.k->p)
2036                                 ? k.k->p
2037                                 : bpos_successor(k.k->p);
2038                         continue;
2039                 }
2040
2041                 if (likely(k.k)) {
2042                         break;
2043                 } else if (likely(!bpos_eq(l->b->key.k.p, SPOS_MAX))) {
2044                         /* Advance to next leaf node: */
2045                         search_key = bpos_successor(l->b->key.k.p);
2046                 } else {
2047                         /* End of btree: */
2048                         bch2_btree_iter_set_pos(iter, SPOS_MAX);
2049                         k = bkey_s_c_null;
2050                         goto out;
2051                 }
2052         }
2053 out:
2054         bch2_btree_iter_verify(iter);
2055
2056         return k;
2057 }
2058
2059 /**
2060  * bch2_btree_iter_peek: returns first key greater than or equal to iterator's
2061  * current position
2062  */
2063 struct bkey_s_c bch2_btree_iter_peek_upto(struct btree_iter *iter, struct bpos end)
2064 {
2065         struct btree_trans *trans = iter->trans;
2066         struct bpos search_key = btree_iter_search_key(iter);
2067         struct bkey_s_c k;
2068         struct bpos iter_pos;
2069         int ret;
2070
2071         EBUG_ON(iter->flags & BTREE_ITER_ALL_LEVELS);
2072         EBUG_ON((iter->flags & BTREE_ITER_FILTER_SNAPSHOTS) && bkey_eq(end, POS_MAX));
2073
2074         if (iter->update_path) {
2075                 bch2_path_put_nokeep(trans, iter->update_path,
2076                                      iter->flags & BTREE_ITER_INTENT);
2077                 iter->update_path = NULL;
2078         }
2079
2080         bch2_btree_iter_verify_entry_exit(iter);
2081
2082         while (1) {
2083                 k = __bch2_btree_iter_peek(iter, search_key);
2084                 if (unlikely(!k.k))
2085                         goto end;
2086                 if (unlikely(bkey_err(k)))
2087                         goto out_no_locked;
2088
2089                 /*
2090                  * iter->pos should be mononotically increasing, and always be
2091                  * equal to the key we just returned - except extents can
2092                  * straddle iter->pos:
2093                  */
2094                 if (!(iter->flags & BTREE_ITER_IS_EXTENTS))
2095                         iter_pos = k.k->p;
2096                 else
2097                         iter_pos = bkey_max(iter->pos, bkey_start_pos(k.k));
2098
2099                 if (unlikely(!(iter->flags & BTREE_ITER_IS_EXTENTS)
2100                              ? bkey_gt(iter_pos, end)
2101                              : bkey_ge(iter_pos, end)))
2102                         goto end;
2103
2104                 if (iter->update_path &&
2105                     !bkey_eq(iter->update_path->pos, k.k->p)) {
2106                         bch2_path_put_nokeep(trans, iter->update_path,
2107                                              iter->flags & BTREE_ITER_INTENT);
2108                         iter->update_path = NULL;
2109                 }
2110
2111                 if ((iter->flags & BTREE_ITER_FILTER_SNAPSHOTS) &&
2112                     (iter->flags & BTREE_ITER_INTENT) &&
2113                     !(iter->flags & BTREE_ITER_IS_EXTENTS) &&
2114                     !iter->update_path) {
2115                         struct bpos pos = k.k->p;
2116
2117                         if (pos.snapshot < iter->snapshot) {
2118                                 search_key = bpos_successor(k.k->p);
2119                                 continue;
2120                         }
2121
2122                         pos.snapshot = iter->snapshot;
2123
2124                         /*
2125                          * advance, same as on exit for iter->path, but only up
2126                          * to snapshot
2127                          */
2128                         __btree_path_get(iter->path, iter->flags & BTREE_ITER_INTENT);
2129                         iter->update_path = iter->path;
2130
2131                         iter->update_path = bch2_btree_path_set_pos(trans,
2132                                                 iter->update_path, pos,
2133                                                 iter->flags & BTREE_ITER_INTENT,
2134                                                 _THIS_IP_);
2135                         ret = bch2_btree_path_traverse(trans, iter->update_path, iter->flags);
2136                         if (unlikely(ret)) {
2137                                 k = bkey_s_c_err(ret);
2138                                 goto out_no_locked;
2139                         }
2140                 }
2141
2142                 /*
2143                  * We can never have a key in a leaf node at POS_MAX, so
2144                  * we don't have to check these successor() calls:
2145                  */
2146                 if ((iter->flags & BTREE_ITER_FILTER_SNAPSHOTS) &&
2147                     !bch2_snapshot_is_ancestor(trans->c,
2148                                                iter->snapshot,
2149                                                k.k->p.snapshot)) {
2150                         search_key = bpos_successor(k.k->p);
2151                         continue;
2152                 }
2153
2154                 if (bkey_whiteout(k.k) &&
2155                     !(iter->flags & BTREE_ITER_ALL_SNAPSHOTS)) {
2156                         search_key = bkey_successor(iter, k.k->p);
2157                         continue;
2158                 }
2159
2160                 break;
2161         }
2162
2163         iter->pos = iter_pos;
2164
2165         iter->path = bch2_btree_path_set_pos(trans, iter->path, k.k->p,
2166                                 iter->flags & BTREE_ITER_INTENT,
2167                                 btree_iter_ip_allocated(iter));
2168
2169         btree_path_set_should_be_locked(iter->path);
2170 out_no_locked:
2171         if (iter->update_path) {
2172                 ret = bch2_btree_path_relock(trans, iter->update_path, _THIS_IP_);
2173                 if (unlikely(ret))
2174                         k = bkey_s_c_err(ret);
2175                 else
2176                         btree_path_set_should_be_locked(iter->update_path);
2177         }
2178
2179         if (!(iter->flags & BTREE_ITER_ALL_SNAPSHOTS))
2180                 iter->pos.snapshot = iter->snapshot;
2181
2182         ret = bch2_btree_iter_verify_ret(iter, k);
2183         if (unlikely(ret)) {
2184                 bch2_btree_iter_set_pos(iter, iter->pos);
2185                 k = bkey_s_c_err(ret);
2186         }
2187
2188         bch2_btree_iter_verify_entry_exit(iter);
2189
2190         return k;
2191 end:
2192         bch2_btree_iter_set_pos(iter, end);
2193         k = bkey_s_c_null;
2194         goto out_no_locked;
2195 }
2196
2197 /**
2198  * bch2_btree_iter_peek_all_levels: returns the first key greater than or equal
2199  * to iterator's current position, returning keys from every level of the btree.
2200  * For keys at different levels of the btree that compare equal, the key from
2201  * the lower level (leaf) is returned first.
2202  */
2203 struct bkey_s_c bch2_btree_iter_peek_all_levels(struct btree_iter *iter)
2204 {
2205         struct btree_trans *trans = iter->trans;
2206         struct bkey_s_c k;
2207         int ret;
2208
2209         EBUG_ON(iter->path->cached);
2210         bch2_btree_iter_verify(iter);
2211         BUG_ON(iter->path->level < iter->min_depth);
2212         BUG_ON(!(iter->flags & BTREE_ITER_ALL_SNAPSHOTS));
2213         EBUG_ON(!(iter->flags & BTREE_ITER_ALL_LEVELS));
2214
2215         while (1) {
2216                 iter->path = bch2_btree_path_set_pos(trans, iter->path, iter->pos,
2217                                         iter->flags & BTREE_ITER_INTENT,
2218                                         btree_iter_ip_allocated(iter));
2219
2220                 ret = bch2_btree_path_traverse(trans, iter->path, iter->flags);
2221                 if (unlikely(ret)) {
2222                         /* ensure that iter->k is consistent with iter->pos: */
2223                         bch2_btree_iter_set_pos(iter, iter->pos);
2224                         k = bkey_s_c_err(ret);
2225                         goto out_no_locked;
2226                 }
2227
2228                 /* Already at end? */
2229                 if (!btree_path_node(iter->path, iter->path->level)) {
2230                         k = bkey_s_c_null;
2231                         goto out_no_locked;
2232                 }
2233
2234                 k = btree_path_level_peek_all(trans->c,
2235                                 &iter->path->l[iter->path->level], &iter->k);
2236
2237                 /* Check if we should go up to the parent node: */
2238                 if (!k.k ||
2239                     (iter->advanced &&
2240                      bpos_eq(path_l(iter->path)->b->key.k.p, iter->pos))) {
2241                         iter->pos = path_l(iter->path)->b->key.k.p;
2242                         btree_path_set_level_up(trans, iter->path);
2243                         iter->advanced = false;
2244                         continue;
2245                 }
2246
2247                 /*
2248                  * Check if we should go back down to a leaf:
2249                  * If we're not in a leaf node, we only return the current key
2250                  * if it exactly matches iter->pos - otherwise we first have to
2251                  * go back to the leaf:
2252                  */
2253                 if (iter->path->level != iter->min_depth &&
2254                     (iter->advanced ||
2255                      !k.k ||
2256                      !bpos_eq(iter->pos, k.k->p))) {
2257                         btree_path_set_level_down(trans, iter->path, iter->min_depth);
2258                         iter->pos = bpos_successor(iter->pos);
2259                         iter->advanced = false;
2260                         continue;
2261                 }
2262
2263                 /* Check if we should go to the next key: */
2264                 if (iter->path->level == iter->min_depth &&
2265                     iter->advanced &&
2266                     k.k &&
2267                     bpos_eq(iter->pos, k.k->p)) {
2268                         iter->pos = bpos_successor(iter->pos);
2269                         iter->advanced = false;
2270                         continue;
2271                 }
2272
2273                 if (iter->advanced &&
2274                     iter->path->level == iter->min_depth &&
2275                     !bpos_eq(k.k->p, iter->pos))
2276                         iter->advanced = false;
2277
2278                 BUG_ON(iter->advanced);
2279                 BUG_ON(!k.k);
2280                 break;
2281         }
2282
2283         iter->pos = k.k->p;
2284         btree_path_set_should_be_locked(iter->path);
2285 out_no_locked:
2286         bch2_btree_iter_verify(iter);
2287
2288         return k;
2289 }
2290
2291 /**
2292  * bch2_btree_iter_next: returns first key greater than iterator's current
2293  * position
2294  */
2295 struct bkey_s_c bch2_btree_iter_next(struct btree_iter *iter)
2296 {
2297         if (!bch2_btree_iter_advance(iter))
2298                 return bkey_s_c_null;
2299
2300         return bch2_btree_iter_peek(iter);
2301 }
2302
2303 /**
2304  * bch2_btree_iter_peek_prev: returns first key less than or equal to
2305  * iterator's current position
2306  */
2307 struct bkey_s_c bch2_btree_iter_peek_prev(struct btree_iter *iter)
2308 {
2309         struct btree_trans *trans = iter->trans;
2310         struct bpos search_key = iter->pos;
2311         struct btree_path *saved_path = NULL;
2312         struct bkey_s_c k;
2313         struct bkey saved_k;
2314         const struct bch_val *saved_v;
2315         int ret;
2316
2317         EBUG_ON(iter->path->cached || iter->path->level);
2318         EBUG_ON(iter->flags & BTREE_ITER_WITH_UPDATES);
2319
2320         if (iter->flags & BTREE_ITER_WITH_JOURNAL)
2321                 return bkey_s_c_err(-EIO);
2322
2323         bch2_btree_iter_verify(iter);
2324         bch2_btree_iter_verify_entry_exit(iter);
2325
2326         if (iter->flags & BTREE_ITER_FILTER_SNAPSHOTS)
2327                 search_key.snapshot = U32_MAX;
2328
2329         while (1) {
2330                 iter->path = bch2_btree_path_set_pos(trans, iter->path, search_key,
2331                                                 iter->flags & BTREE_ITER_INTENT,
2332                                                 btree_iter_ip_allocated(iter));
2333
2334                 ret = bch2_btree_path_traverse(trans, iter->path, iter->flags);
2335                 if (unlikely(ret)) {
2336                         /* ensure that iter->k is consistent with iter->pos: */
2337                         bch2_btree_iter_set_pos(iter, iter->pos);
2338                         k = bkey_s_c_err(ret);
2339                         goto out_no_locked;
2340                 }
2341
2342                 k = btree_path_level_peek(trans, iter->path,
2343                                           &iter->path->l[0], &iter->k);
2344                 if (!k.k ||
2345                     ((iter->flags & BTREE_ITER_IS_EXTENTS)
2346                      ? bpos_ge(bkey_start_pos(k.k), search_key)
2347                      : bpos_gt(k.k->p, search_key)))
2348                         k = btree_path_level_prev(trans, iter->path,
2349                                                   &iter->path->l[0], &iter->k);
2350
2351                 if (likely(k.k)) {
2352                         if (iter->flags & BTREE_ITER_FILTER_SNAPSHOTS) {
2353                                 if (k.k->p.snapshot == iter->snapshot)
2354                                         goto got_key;
2355
2356                                 /*
2357                                  * If we have a saved candidate, and we're no
2358                                  * longer at the same _key_ (not pos), return
2359                                  * that candidate
2360                                  */
2361                                 if (saved_path && !bkey_eq(k.k->p, saved_k.p)) {
2362                                         bch2_path_put_nokeep(trans, iter->path,
2363                                                       iter->flags & BTREE_ITER_INTENT);
2364                                         iter->path = saved_path;
2365                                         saved_path = NULL;
2366                                         iter->k = saved_k;
2367                                         k.v     = saved_v;
2368                                         goto got_key;
2369                                 }
2370
2371                                 if (bch2_snapshot_is_ancestor(iter->trans->c,
2372                                                               iter->snapshot,
2373                                                               k.k->p.snapshot)) {
2374                                         if (saved_path)
2375                                                 bch2_path_put_nokeep(trans, saved_path,
2376                                                       iter->flags & BTREE_ITER_INTENT);
2377                                         saved_path = btree_path_clone(trans, iter->path,
2378                                                                 iter->flags & BTREE_ITER_INTENT);
2379                                         saved_k = *k.k;
2380                                         saved_v = k.v;
2381                                 }
2382
2383                                 search_key = bpos_predecessor(k.k->p);
2384                                 continue;
2385                         }
2386 got_key:
2387                         if (bkey_whiteout(k.k) &&
2388                             !(iter->flags & BTREE_ITER_ALL_SNAPSHOTS)) {
2389                                 search_key = bkey_predecessor(iter, k.k->p);
2390                                 if (iter->flags & BTREE_ITER_FILTER_SNAPSHOTS)
2391                                         search_key.snapshot = U32_MAX;
2392                                 continue;
2393                         }
2394
2395                         break;
2396                 } else if (likely(!bpos_eq(iter->path->l[0].b->data->min_key, POS_MIN))) {
2397                         /* Advance to previous leaf node: */
2398                         search_key = bpos_predecessor(iter->path->l[0].b->data->min_key);
2399                 } else {
2400                         /* Start of btree: */
2401                         bch2_btree_iter_set_pos(iter, POS_MIN);
2402                         k = bkey_s_c_null;
2403                         goto out_no_locked;
2404                 }
2405         }
2406
2407         EBUG_ON(bkey_gt(bkey_start_pos(k.k), iter->pos));
2408
2409         /* Extents can straddle iter->pos: */
2410         if (bkey_lt(k.k->p, iter->pos))
2411                 iter->pos = k.k->p;
2412
2413         if (iter->flags & BTREE_ITER_FILTER_SNAPSHOTS)
2414                 iter->pos.snapshot = iter->snapshot;
2415
2416         btree_path_set_should_be_locked(iter->path);
2417 out_no_locked:
2418         if (saved_path)
2419                 bch2_path_put_nokeep(trans, saved_path, iter->flags & BTREE_ITER_INTENT);
2420
2421         bch2_btree_iter_verify_entry_exit(iter);
2422         bch2_btree_iter_verify(iter);
2423
2424         return k;
2425 }
2426
2427 /**
2428  * bch2_btree_iter_prev: returns first key less than iterator's current
2429  * position
2430  */
2431 struct bkey_s_c bch2_btree_iter_prev(struct btree_iter *iter)
2432 {
2433         if (!bch2_btree_iter_rewind(iter))
2434                 return bkey_s_c_null;
2435
2436         return bch2_btree_iter_peek_prev(iter);
2437 }
2438
2439 struct bkey_s_c bch2_btree_iter_peek_slot(struct btree_iter *iter)
2440 {
2441         struct btree_trans *trans = iter->trans;
2442         struct bpos search_key;
2443         struct bkey_s_c k;
2444         int ret;
2445
2446         bch2_btree_iter_verify(iter);
2447         bch2_btree_iter_verify_entry_exit(iter);
2448         EBUG_ON(iter->flags & BTREE_ITER_ALL_LEVELS);
2449         EBUG_ON(iter->path->level && (iter->flags & BTREE_ITER_WITH_KEY_CACHE));
2450
2451         /* extents can't span inode numbers: */
2452         if ((iter->flags & BTREE_ITER_IS_EXTENTS) &&
2453             unlikely(iter->pos.offset == KEY_OFFSET_MAX)) {
2454                 if (iter->pos.inode == KEY_INODE_MAX)
2455                         return bkey_s_c_null;
2456
2457                 bch2_btree_iter_set_pos(iter, bpos_nosnap_successor(iter->pos));
2458         }
2459
2460         search_key = btree_iter_search_key(iter);
2461         iter->path = bch2_btree_path_set_pos(trans, iter->path, search_key,
2462                                         iter->flags & BTREE_ITER_INTENT,
2463                                         btree_iter_ip_allocated(iter));
2464
2465         ret = bch2_btree_path_traverse(trans, iter->path, iter->flags);
2466         if (unlikely(ret)) {
2467                 k = bkey_s_c_err(ret);
2468                 goto out_no_locked;
2469         }
2470
2471         if ((iter->flags & BTREE_ITER_CACHED) ||
2472             !(iter->flags & (BTREE_ITER_IS_EXTENTS|BTREE_ITER_FILTER_SNAPSHOTS))) {
2473                 struct bkey_i *next_update;
2474
2475                 if ((next_update = btree_trans_peek_updates(iter)) &&
2476                     bpos_eq(next_update->k.p, iter->pos)) {
2477                         iter->k = next_update->k;
2478                         k = bkey_i_to_s_c(next_update);
2479                         goto out;
2480                 }
2481
2482                 if (unlikely(iter->flags & BTREE_ITER_WITH_JOURNAL) &&
2483                     (k = btree_trans_peek_slot_journal(trans, iter)).k)
2484                         goto out;
2485
2486                 if (unlikely(iter->flags & BTREE_ITER_WITH_KEY_CACHE) &&
2487                     (k = btree_trans_peek_key_cache(iter, iter->pos)).k) {
2488                         if (!bkey_err(k))
2489                                 iter->k = *k.k;
2490                         /* We're not returning a key from iter->path: */
2491                         goto out_no_locked;
2492                 }
2493
2494                 k = bch2_btree_path_peek_slot(iter->path, &iter->k);
2495                 if (unlikely(!k.k))
2496                         goto out_no_locked;
2497         } else {
2498                 struct bpos next;
2499                 struct bpos end = iter->pos;
2500
2501                 if (iter->flags & BTREE_ITER_IS_EXTENTS)
2502                         end.offset = U64_MAX;
2503
2504                 EBUG_ON(iter->path->level);
2505
2506                 if (iter->flags & BTREE_ITER_INTENT) {
2507                         struct btree_iter iter2;
2508
2509                         bch2_trans_copy_iter(&iter2, iter);
2510                         k = bch2_btree_iter_peek_upto(&iter2, end);
2511
2512                         if (k.k && !bkey_err(k)) {
2513                                 iter->k = iter2.k;
2514                                 k.k = &iter->k;
2515                         }
2516                         bch2_trans_iter_exit(trans, &iter2);
2517                 } else {
2518                         struct bpos pos = iter->pos;
2519
2520                         k = bch2_btree_iter_peek_upto(iter, end);
2521                         if (unlikely(bkey_err(k)))
2522                                 bch2_btree_iter_set_pos(iter, pos);
2523                         else
2524                                 iter->pos = pos;
2525                 }
2526
2527                 if (unlikely(bkey_err(k)))
2528                         goto out_no_locked;
2529
2530                 next = k.k ? bkey_start_pos(k.k) : POS_MAX;
2531
2532                 if (bkey_lt(iter->pos, next)) {
2533                         bkey_init(&iter->k);
2534                         iter->k.p = iter->pos;
2535
2536                         if (iter->flags & BTREE_ITER_IS_EXTENTS) {
2537                                 bch2_key_resize(&iter->k,
2538                                                 min_t(u64, KEY_SIZE_MAX,
2539                                                       (next.inode == iter->pos.inode
2540                                                        ? next.offset
2541                                                        : KEY_OFFSET_MAX) -
2542                                                       iter->pos.offset));
2543                                 EBUG_ON(!iter->k.size);
2544                         }
2545
2546                         k = (struct bkey_s_c) { &iter->k, NULL };
2547                 }
2548         }
2549 out:
2550         btree_path_set_should_be_locked(iter->path);
2551 out_no_locked:
2552         bch2_btree_iter_verify_entry_exit(iter);
2553         bch2_btree_iter_verify(iter);
2554         ret = bch2_btree_iter_verify_ret(iter, k);
2555         if (unlikely(ret))
2556                 return bkey_s_c_err(ret);
2557
2558         return k;
2559 }
2560
2561 struct bkey_s_c bch2_btree_iter_next_slot(struct btree_iter *iter)
2562 {
2563         if (!bch2_btree_iter_advance(iter))
2564                 return bkey_s_c_null;
2565
2566         return bch2_btree_iter_peek_slot(iter);
2567 }
2568
2569 struct bkey_s_c bch2_btree_iter_prev_slot(struct btree_iter *iter)
2570 {
2571         if (!bch2_btree_iter_rewind(iter))
2572                 return bkey_s_c_null;
2573
2574         return bch2_btree_iter_peek_slot(iter);
2575 }
2576
2577 /* new transactional stuff: */
2578
2579 #ifdef CONFIG_BCACHEFS_DEBUG
2580 static void btree_trans_verify_sorted_refs(struct btree_trans *trans)
2581 {
2582         struct btree_path *path;
2583         unsigned i;
2584
2585         BUG_ON(trans->nr_sorted != hweight64(trans->paths_allocated));
2586
2587         trans_for_each_path(trans, path) {
2588                 BUG_ON(path->sorted_idx >= trans->nr_sorted);
2589                 BUG_ON(trans->sorted[path->sorted_idx] != path->idx);
2590         }
2591
2592         for (i = 0; i < trans->nr_sorted; i++) {
2593                 unsigned idx = trans->sorted[i];
2594
2595                 EBUG_ON(!(trans->paths_allocated & (1ULL << idx)));
2596                 BUG_ON(trans->paths[idx].sorted_idx != i);
2597         }
2598 }
2599
2600 static void btree_trans_verify_sorted(struct btree_trans *trans)
2601 {
2602         struct btree_path *path, *prev = NULL;
2603         unsigned i;
2604
2605         if (!bch2_debug_check_iterators)
2606                 return;
2607
2608         trans_for_each_path_inorder(trans, path, i) {
2609                 if (prev && btree_path_cmp(prev, path) > 0) {
2610                         __bch2_dump_trans_paths_updates(trans, true);
2611                         panic("trans paths out of order!\n");
2612                 }
2613                 prev = path;
2614         }
2615 }
2616 #else
2617 static inline void btree_trans_verify_sorted_refs(struct btree_trans *trans) {}
2618 static inline void btree_trans_verify_sorted(struct btree_trans *trans) {}
2619 #endif
2620
2621 void __bch2_btree_trans_sort_paths(struct btree_trans *trans)
2622 {
2623         int i, l = 0, r = trans->nr_sorted, inc = 1;
2624         bool swapped;
2625
2626         btree_trans_verify_sorted_refs(trans);
2627
2628         if (trans->paths_sorted)
2629                 goto out;
2630
2631         /*
2632          * Cocktail shaker sort: this is efficient because iterators will be
2633          * mostly sorted.
2634          */
2635         do {
2636                 swapped = false;
2637
2638                 for (i = inc > 0 ? l : r - 2;
2639                      i + 1 < r && i >= l;
2640                      i += inc) {
2641                         if (btree_path_cmp(trans->paths + trans->sorted[i],
2642                                            trans->paths + trans->sorted[i + 1]) > 0) {
2643                                 swap(trans->sorted[i], trans->sorted[i + 1]);
2644                                 trans->paths[trans->sorted[i]].sorted_idx = i;
2645                                 trans->paths[trans->sorted[i + 1]].sorted_idx = i + 1;
2646                                 swapped = true;
2647                         }
2648                 }
2649
2650                 if (inc > 0)
2651                         --r;
2652                 else
2653                         l++;
2654                 inc = -inc;
2655         } while (swapped);
2656
2657         trans->paths_sorted = true;
2658 out:
2659         btree_trans_verify_sorted(trans);
2660 }
2661
2662 static inline void btree_path_list_remove(struct btree_trans *trans,
2663                                           struct btree_path *path)
2664 {
2665         unsigned i;
2666
2667         EBUG_ON(path->sorted_idx >= trans->nr_sorted);
2668 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
2669         trans->nr_sorted--;
2670         memmove_u64s_down_small(trans->sorted + path->sorted_idx,
2671                                 trans->sorted + path->sorted_idx + 1,
2672                                 DIV_ROUND_UP(trans->nr_sorted - path->sorted_idx, 8));
2673 #else
2674         array_remove_item(trans->sorted, trans->nr_sorted, path->sorted_idx);
2675 #endif
2676         for (i = path->sorted_idx; i < trans->nr_sorted; i++)
2677                 trans->paths[trans->sorted[i]].sorted_idx = i;
2678
2679         path->sorted_idx = U8_MAX;
2680 }
2681
2682 static inline void btree_path_list_add(struct btree_trans *trans,
2683                                        struct btree_path *pos,
2684                                        struct btree_path *path)
2685 {
2686         unsigned i;
2687
2688         path->sorted_idx = pos ? pos->sorted_idx + 1 : trans->nr_sorted;
2689
2690 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
2691         memmove_u64s_up_small(trans->sorted + path->sorted_idx + 1,
2692                               trans->sorted + path->sorted_idx,
2693                               DIV_ROUND_UP(trans->nr_sorted - path->sorted_idx, 8));
2694         trans->nr_sorted++;
2695         trans->sorted[path->sorted_idx] = path->idx;
2696 #else
2697         array_insert_item(trans->sorted, trans->nr_sorted, path->sorted_idx, path->idx);
2698 #endif
2699
2700         for (i = path->sorted_idx; i < trans->nr_sorted; i++)
2701                 trans->paths[trans->sorted[i]].sorted_idx = i;
2702
2703         btree_trans_verify_sorted_refs(trans);
2704 }
2705
2706 void bch2_trans_iter_exit(struct btree_trans *trans, struct btree_iter *iter)
2707 {
2708         if (iter->path)
2709                 bch2_path_put(trans, iter->path,
2710                               iter->flags & BTREE_ITER_INTENT);
2711         if (iter->update_path)
2712                 bch2_path_put_nokeep(trans, iter->update_path,
2713                               iter->flags & BTREE_ITER_INTENT);
2714         if (iter->key_cache_path)
2715                 bch2_path_put(trans, iter->key_cache_path,
2716                               iter->flags & BTREE_ITER_INTENT);
2717         iter->path = NULL;
2718         iter->update_path = NULL;
2719         iter->key_cache_path = NULL;
2720 }
2721
2722 static inline void bch2_trans_iter_init_inlined(struct btree_trans *trans,
2723                           struct btree_iter *iter,
2724                           unsigned btree_id, struct bpos pos,
2725                           unsigned flags)
2726 {
2727         bch2_trans_iter_init_common(trans, iter, btree_id, pos, 0, 0,
2728                                bch2_btree_iter_flags(trans, btree_id, flags),
2729                                _RET_IP_);
2730 }
2731
2732 void bch2_trans_iter_init_outlined(struct btree_trans *trans,
2733                           struct btree_iter *iter,
2734                           unsigned btree_id, struct bpos pos,
2735                           unsigned flags)
2736 {
2737         bch2_trans_iter_init_common(trans, iter, btree_id, pos, 0, 0,
2738                                bch2_btree_iter_flags(trans, btree_id, flags),
2739                                _RET_IP_);
2740 }
2741
2742 void bch2_trans_node_iter_init(struct btree_trans *trans,
2743                                struct btree_iter *iter,
2744                                enum btree_id btree_id,
2745                                struct bpos pos,
2746                                unsigned locks_want,
2747                                unsigned depth,
2748                                unsigned flags)
2749 {
2750        flags |= BTREE_ITER_NOT_EXTENTS;
2751        flags |= __BTREE_ITER_ALL_SNAPSHOTS;
2752        flags |= BTREE_ITER_ALL_SNAPSHOTS;
2753
2754         bch2_trans_iter_init_common(trans, iter, btree_id, pos, locks_want, depth,
2755                                __bch2_btree_iter_flags(trans, btree_id, flags),
2756                                _RET_IP_);
2757
2758         iter->min_depth = depth;
2759
2760         BUG_ON(iter->path->locks_want    < min(locks_want, BTREE_MAX_DEPTH));
2761         BUG_ON(iter->path->level        != depth);
2762         BUG_ON(iter->min_depth          != depth);
2763 }
2764
2765 void bch2_trans_copy_iter(struct btree_iter *dst, struct btree_iter *src)
2766 {
2767         *dst = *src;
2768         if (src->path)
2769                 __btree_path_get(src->path, src->flags & BTREE_ITER_INTENT);
2770         if (src->update_path)
2771                 __btree_path_get(src->update_path, src->flags & BTREE_ITER_INTENT);
2772         dst->key_cache_path = NULL;
2773 }
2774
2775 void *__bch2_trans_kmalloc(struct btree_trans *trans, size_t size)
2776 {
2777         unsigned new_top = trans->mem_top + size;
2778         size_t old_bytes = trans->mem_bytes;
2779         size_t new_bytes = roundup_pow_of_two(new_top);
2780         void *new_mem;
2781         void *p;
2782
2783         trans->mem_max = max(trans->mem_max, new_top);
2784
2785         WARN_ON_ONCE(new_bytes > BTREE_TRANS_MEM_MAX);
2786
2787         new_mem = krealloc(trans->mem, new_bytes, GFP_NOFS);
2788         if (!new_mem && new_bytes <= BTREE_TRANS_MEM_MAX) {
2789                 new_mem = mempool_alloc(&trans->c->btree_trans_mem_pool, GFP_KERNEL);
2790                 new_bytes = BTREE_TRANS_MEM_MAX;
2791                 kfree(trans->mem);
2792         }
2793
2794         if (!new_mem)
2795                 return ERR_PTR(-ENOMEM);
2796
2797         trans->mem = new_mem;
2798         trans->mem_bytes = new_bytes;
2799
2800         if (old_bytes) {
2801                 trace_and_count(trans->c, trans_restart_mem_realloced, trans, _RET_IP_, new_bytes);
2802                 return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_mem_realloced));
2803         }
2804
2805         p = trans->mem + trans->mem_top;
2806         trans->mem_top += size;
2807         memset(p, 0, size);
2808         return p;
2809 }
2810
2811 static noinline void bch2_trans_reset_srcu_lock(struct btree_trans *trans)
2812 {
2813         struct bch_fs *c = trans->c;
2814         struct btree_path *path;
2815
2816         trans_for_each_path(trans, path)
2817                 if (path->cached && !btree_node_locked(path, 0))
2818                         path->l[0].b = ERR_PTR(-BCH_ERR_no_btree_node_srcu_reset);
2819
2820         srcu_read_unlock(&c->btree_trans_barrier, trans->srcu_idx);
2821         trans->srcu_idx = srcu_read_lock(&c->btree_trans_barrier);
2822         trans->srcu_lock_time   = jiffies;
2823 }
2824
2825 /**
2826  * bch2_trans_begin() - reset a transaction after a interrupted attempt
2827  * @trans: transaction to reset
2828  *
2829  * While iterating over nodes or updating nodes a attempt to lock a btree node
2830  * may return BCH_ERR_transaction_restart when the trylock fails. When this
2831  * occurs bch2_trans_begin() should be called and the transaction retried.
2832  */
2833 u32 bch2_trans_begin(struct btree_trans *trans)
2834 {
2835         struct btree_path *path;
2836
2837         bch2_trans_reset_updates(trans);
2838
2839         trans->restart_count++;
2840         trans->mem_top                  = 0;
2841
2842         trans_for_each_path(trans, path) {
2843                 path->should_be_locked = false;
2844
2845                 /*
2846                  * If the transaction wasn't restarted, we're presuming to be
2847                  * doing something new: dont keep iterators excpt the ones that
2848                  * are in use - except for the subvolumes btree:
2849                  */
2850                 if (!trans->restarted && path->btree_id != BTREE_ID_subvolumes)
2851                         path->preserve = false;
2852
2853                 /*
2854                  * XXX: we probably shouldn't be doing this if the transaction
2855                  * was restarted, but currently we still overflow transaction
2856                  * iterators if we do that
2857                  */
2858                 if (!path->ref && !path->preserve)
2859                         __bch2_path_free(trans, path);
2860                 else
2861                         path->preserve = false;
2862         }
2863
2864         if (!trans->restarted &&
2865             (need_resched() ||
2866              local_clock() - trans->last_begin_time > BTREE_TRANS_MAX_LOCK_HOLD_TIME_NS)) {
2867                 bch2_trans_unlock(trans);
2868                 cond_resched();
2869                 bch2_trans_relock(trans);
2870         }
2871
2872         if (unlikely(time_after(jiffies, trans->srcu_lock_time + msecs_to_jiffies(10))))
2873                 bch2_trans_reset_srcu_lock(trans);
2874
2875         trans->last_begin_ip = _RET_IP_;
2876         if (trans->restarted) {
2877                 bch2_btree_path_traverse_all(trans);
2878                 trans->notrace_relock_fail = false;
2879         }
2880
2881         trans->last_begin_time = local_clock();
2882         return trans->restart_count;
2883 }
2884
2885 static void bch2_trans_alloc_paths(struct btree_trans *trans, struct bch_fs *c)
2886 {
2887         size_t paths_bytes      = sizeof(struct btree_path) * BTREE_ITER_MAX;
2888         size_t updates_bytes    = sizeof(struct btree_insert_entry) * BTREE_ITER_MAX;
2889         void *p = NULL;
2890
2891         BUG_ON(trans->used_mempool);
2892
2893 #ifdef __KERNEL__
2894         p = this_cpu_xchg(c->btree_paths_bufs->path, NULL);
2895 #endif
2896         if (!p)
2897                 p = mempool_alloc(&trans->c->btree_paths_pool, GFP_NOFS);
2898
2899         trans->paths            = p; p += paths_bytes;
2900         trans->updates          = p; p += updates_bytes;
2901 }
2902
2903 const char *bch2_btree_transaction_fns[BCH_TRANSACTIONS_NR];
2904
2905 unsigned bch2_trans_get_fn_idx(const char *fn)
2906 {
2907         unsigned i;
2908
2909         for (i = 0; i < ARRAY_SIZE(bch2_btree_transaction_fns); i++)
2910                 if (!bch2_btree_transaction_fns[i] ||
2911                     bch2_btree_transaction_fns[i] == fn) {
2912                         bch2_btree_transaction_fns[i] = fn;
2913                         return i;
2914                 }
2915
2916         pr_warn_once("BCH_TRANSACTIONS_NR not big enough!");
2917         return i;
2918 }
2919
2920 void __bch2_trans_init(struct btree_trans *trans, struct bch_fs *c, unsigned fn_idx)
2921         __acquires(&c->btree_trans_barrier)
2922 {
2923         struct btree_transaction_stats *s;
2924
2925         BUG_ON(lock_class_is_held(&bch2_btree_node_lock_key));
2926
2927         memset(trans, 0, sizeof(*trans));
2928         trans->c                = c;
2929         trans->fn               = fn_idx < ARRAY_SIZE(bch2_btree_transaction_fns)
2930                 ? bch2_btree_transaction_fns[fn_idx] : NULL;
2931         trans->last_begin_time  = local_clock();
2932         trans->fn_idx           = fn_idx;
2933         trans->locking_wait.task = current;
2934         trans->journal_replay_not_finished =
2935                 !test_bit(JOURNAL_REPLAY_DONE, &c->journal.flags);
2936         closure_init_stack(&trans->ref);
2937
2938         bch2_trans_alloc_paths(trans, c);
2939
2940         s = btree_trans_stats(trans);
2941         if (s && s->max_mem) {
2942                 unsigned expected_mem_bytes = roundup_pow_of_two(s->max_mem);
2943
2944                 trans->mem = kmalloc(expected_mem_bytes, GFP_KERNEL);
2945
2946                 if (!unlikely(trans->mem)) {
2947                         trans->mem = mempool_alloc(&c->btree_trans_mem_pool, GFP_KERNEL);
2948                         trans->mem_bytes = BTREE_TRANS_MEM_MAX;
2949                 } else {
2950                         trans->mem_bytes = expected_mem_bytes;
2951                 }
2952         }
2953
2954         if (s) {
2955                 trans->nr_max_paths = s->nr_max_paths;
2956                 trans->wb_updates_size = s->wb_updates_size;
2957         }
2958
2959         trans->srcu_idx = srcu_read_lock(&c->btree_trans_barrier);
2960         trans->srcu_lock_time   = jiffies;
2961
2962         if (IS_ENABLED(CONFIG_BCACHEFS_DEBUG_TRANSACTIONS)) {
2963                 struct btree_trans *pos;
2964
2965                 mutex_lock(&c->btree_trans_lock);
2966                 list_for_each_entry(pos, &c->btree_trans_list, list) {
2967                         if (trans->locking_wait.task->pid < pos->locking_wait.task->pid) {
2968                                 list_add_tail(&trans->list, &pos->list);
2969                                 goto list_add_done;
2970                         }
2971                 }
2972                 list_add_tail(&trans->list, &c->btree_trans_list);
2973 list_add_done:
2974                 mutex_unlock(&c->btree_trans_lock);
2975         }
2976 }
2977
2978 static void check_btree_paths_leaked(struct btree_trans *trans)
2979 {
2980 #ifdef CONFIG_BCACHEFS_DEBUG
2981         struct bch_fs *c = trans->c;
2982         struct btree_path *path;
2983
2984         trans_for_each_path(trans, path)
2985                 if (path->ref)
2986                         goto leaked;
2987         return;
2988 leaked:
2989         bch_err(c, "btree paths leaked from %s!", trans->fn);
2990         trans_for_each_path(trans, path)
2991                 if (path->ref)
2992                         printk(KERN_ERR "  btree %s %pS\n",
2993                                bch2_btree_ids[path->btree_id],
2994                                (void *) path->ip_allocated);
2995         /* Be noisy about this: */
2996         bch2_fatal_error(c);
2997 #endif
2998 }
2999
3000 void bch2_trans_exit(struct btree_trans *trans)
3001         __releases(&c->btree_trans_barrier)
3002 {
3003         struct btree_insert_entry *i;
3004         struct bch_fs *c = trans->c;
3005         struct btree_transaction_stats *s = btree_trans_stats(trans);
3006
3007         bch2_trans_unlock(trans);
3008
3009         closure_sync(&trans->ref);
3010
3011         if (s)
3012                 s->max_mem = max(s->max_mem, trans->mem_max);
3013
3014         trans_for_each_update(trans, i)
3015                 __btree_path_put(i->path, true);
3016         trans->nr_updates               = 0;
3017
3018         check_btree_paths_leaked(trans);
3019
3020         if (IS_ENABLED(CONFIG_BCACHEFS_DEBUG_TRANSACTIONS)) {
3021                 mutex_lock(&c->btree_trans_lock);
3022                 list_del(&trans->list);
3023                 mutex_unlock(&c->btree_trans_lock);
3024         }
3025
3026         srcu_read_unlock(&c->btree_trans_barrier, trans->srcu_idx);
3027
3028         bch2_journal_preres_put(&c->journal, &trans->journal_preres);
3029
3030         kfree(trans->extra_journal_entries.data);
3031
3032         if (trans->fs_usage_deltas) {
3033                 if (trans->fs_usage_deltas->size + sizeof(trans->fs_usage_deltas) ==
3034                     REPLICAS_DELTA_LIST_MAX)
3035                         mempool_free(trans->fs_usage_deltas,
3036                                      &c->replicas_delta_pool);
3037                 else
3038                         kfree(trans->fs_usage_deltas);
3039         }
3040
3041         if (trans->mem_bytes == BTREE_TRANS_MEM_MAX)
3042                 mempool_free(trans->mem, &c->btree_trans_mem_pool);
3043         else
3044                 kfree(trans->mem);
3045
3046 #ifdef __KERNEL__
3047         /*
3048          * Userspace doesn't have a real percpu implementation:
3049          */
3050         trans->paths = this_cpu_xchg(c->btree_paths_bufs->path, trans->paths);
3051 #endif
3052
3053         if (trans->paths)
3054                 mempool_free(trans->paths, &c->btree_paths_pool);
3055
3056 #ifdef CONFIG_BCACHEFS_DEBUG
3057         darray_exit(&trans->last_restarted);
3058 #endif
3059
3060         trans->mem      = (void *) 0x1;
3061         trans->paths    = (void *) 0x1;
3062 }
3063
3064 static void __maybe_unused
3065 bch2_btree_bkey_cached_common_to_text(struct printbuf *out,
3066                                       struct btree_bkey_cached_common *b)
3067 {
3068         struct six_lock_count c = six_lock_counts(&b->lock);
3069         struct task_struct *owner;
3070         pid_t pid;
3071
3072         rcu_read_lock();
3073         owner = READ_ONCE(b->lock.owner);
3074         pid = owner ? owner->pid : 0;
3075         rcu_read_unlock();
3076
3077         prt_tab(out);
3078         prt_printf(out, "%px %c l=%u %s:", b, b->cached ? 'c' : 'b',
3079                    b->level, bch2_btree_ids[b->btree_id]);
3080         bch2_bpos_to_text(out, btree_node_pos(b));
3081
3082         prt_tab(out);
3083         prt_printf(out, " locks %u:%u:%u held by pid %u",
3084                    c.n[0], c.n[1], c.n[2], pid);
3085 }
3086
3087 void bch2_btree_trans_to_text(struct printbuf *out, struct btree_trans *trans)
3088 {
3089         struct btree_path *path;
3090         struct btree_bkey_cached_common *b;
3091         static char lock_types[] = { 'r', 'i', 'w' };
3092         unsigned l;
3093
3094         if (!out->nr_tabstops) {
3095                 printbuf_tabstop_push(out, 16);
3096                 printbuf_tabstop_push(out, 32);
3097         }
3098
3099         prt_printf(out, "%i %s\n", trans->locking_wait.task->pid, trans->fn);
3100
3101         trans_for_each_path(trans, path) {
3102                 if (!path->nodes_locked)
3103                         continue;
3104
3105                 prt_printf(out, "  path %u %c l=%u %s:",
3106                        path->idx,
3107                        path->cached ? 'c' : 'b',
3108                        path->level,
3109                        bch2_btree_ids[path->btree_id]);
3110                 bch2_bpos_to_text(out, path->pos);
3111                 prt_newline(out);
3112
3113                 for (l = 0; l < BTREE_MAX_DEPTH; l++) {
3114                         if (btree_node_locked(path, l) &&
3115                             !IS_ERR_OR_NULL(b = (void *) READ_ONCE(path->l[l].b))) {
3116                                 prt_printf(out, "    %c l=%u ",
3117                                            lock_types[btree_node_locked_type(path, l)], l);
3118                                 bch2_btree_bkey_cached_common_to_text(out, b);
3119                                 prt_newline(out);
3120                         }
3121                 }
3122         }
3123
3124         b = READ_ONCE(trans->locking);
3125         if (b) {
3126                 prt_printf(out, "  blocked for %lluus on",
3127                            div_u64(local_clock() - trans->locking_wait.start_time,
3128                                    1000));
3129                 prt_newline(out);
3130                 prt_printf(out, "    %c", lock_types[trans->locking_wait.lock_want]);
3131                 bch2_btree_bkey_cached_common_to_text(out, b);
3132                 prt_newline(out);
3133         }
3134 }
3135
3136 void bch2_fs_btree_iter_exit(struct bch_fs *c)
3137 {
3138         struct btree_transaction_stats *s;
3139
3140         for (s = c->btree_transaction_stats;
3141              s < c->btree_transaction_stats + ARRAY_SIZE(c->btree_transaction_stats);
3142              s++) {
3143                 kfree(s->max_paths_text);
3144                 bch2_time_stats_exit(&s->lock_hold_times);
3145         }
3146
3147         if (c->btree_trans_barrier_initialized)
3148                 cleanup_srcu_struct(&c->btree_trans_barrier);
3149         mempool_exit(&c->btree_trans_mem_pool);
3150         mempool_exit(&c->btree_paths_pool);
3151 }
3152
3153 int bch2_fs_btree_iter_init(struct bch_fs *c)
3154 {
3155         struct btree_transaction_stats *s;
3156         unsigned nr = BTREE_ITER_MAX;
3157         int ret;
3158
3159         for (s = c->btree_transaction_stats;
3160              s < c->btree_transaction_stats + ARRAY_SIZE(c->btree_transaction_stats);
3161              s++) {
3162                 bch2_time_stats_init(&s->lock_hold_times);
3163                 mutex_init(&s->lock);
3164         }
3165
3166         INIT_LIST_HEAD(&c->btree_trans_list);
3167         mutex_init(&c->btree_trans_lock);
3168
3169         ret   = mempool_init_kmalloc_pool(&c->btree_paths_pool, 1,
3170                         sizeof(struct btree_path) * nr +
3171                         sizeof(struct btree_insert_entry) * nr) ?:
3172                 mempool_init_kmalloc_pool(&c->btree_trans_mem_pool, 1,
3173                                           BTREE_TRANS_MEM_MAX) ?:
3174                 init_srcu_struct(&c->btree_trans_barrier);
3175         if (!ret)
3176                 c->btree_trans_barrier_initialized = true;
3177         return ret;
3178 }