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

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _BCACHEFS_BTREE_ITER_H
   3 #define _BCACHEFS_BTREE_ITER_H
   4
   5 #include "bset.h"
   6 #include "btree_types.h"
   7
   8 #include <trace/events/bcachefs.h>
   9
  10 static inline void __btree_path_get(struct btree_path *path, bool intent)
  11 {
  12         path->ref++;
  13         path->intent_ref += intent;
  14 }
  15
  16 static inline bool __btree_path_put(struct btree_path *path, bool intent)
  17 {
  18         EBUG_ON(!path->ref);
  19         EBUG_ON(!path->intent_ref && intent);
  20         path->intent_ref -= intent;
  21         return --path->ref == 0;
  22 }
  23
  24 static inline void btree_path_set_dirty(struct btree_path *path,
  25                                         enum btree_path_uptodate u)
  26 {
  27         path->uptodate = max_t(unsigned, path->uptodate, u);
  28 }
  29
  30 static inline struct btree *btree_path_node(struct btree_path *path,
  31                                             unsigned level)
  32 {
  33         return level < BTREE_MAX_DEPTH ? path->l[level].b : NULL;
  34 }
  35
  36 static inline bool btree_node_lock_seq_matches(const struct btree_path *path,
  37                                         const struct btree *b, unsigned level)
  38 {
  39         /*
  40          * We don't compare the low bits of the lock sequence numbers because
  41          * @path might have taken a write lock on @b, and we don't want to skip
  42          * the linked path if the sequence numbers were equal before taking that
  43          * write lock. The lock sequence number is incremented by taking and
  44          * releasing write locks and is even when unlocked:
  45          */
  46         return path->l[level].lock_seq >> 1 == b->c.lock.state.seq >> 1;
  47 }
  48
  49 static inline struct btree *btree_node_parent(struct btree_path *path,
  50                                               struct btree *b)
  51 {
  52         return btree_path_node(path, b->c.level + 1);
  53 }
  54
  55 /* Iterate over paths within a transaction: */
  56
  57 static inline struct btree_path *
  58 __trans_next_path(struct btree_trans *trans, unsigned idx)
  59 {
  60         u64 l;
  61
  62         if (idx == BTREE_ITER_MAX)
  63                 return NULL;
  64
  65         l = trans->paths_allocated >> idx;
  66         if (!l)
  67                 return NULL;
  68
  69         idx += __ffs64(l);
  70         EBUG_ON(idx >= BTREE_ITER_MAX);
  71         EBUG_ON(trans->paths[idx].idx != idx);
  72         return &trans->paths[idx];
  73 }
  74
  75 void bch2_btree_path_check_sort(struct btree_trans *, struct btree_path *, int);
  76
  77 #define trans_for_each_path_from(_trans, _path, _start)                 \
  78         for (_path = __trans_next_path((_trans), _start);               \
  79              (_path);                                                   \
  80              _path = __trans_next_path((_trans), (_path)->idx + 1))
  81
  82 #define trans_for_each_path(_trans, _path)                              \
  83         trans_for_each_path_from(_trans, _path, 0)
  84
  85 static inline struct btree_path *next_btree_path(struct btree_trans *trans, struct btree_path *path)
  86 {
  87         unsigned idx = path ? path->sorted_idx + 1 : 0;
  88
  89         EBUG_ON(idx > trans->nr_sorted);
  90
  91         return idx < trans->nr_sorted
  92                 ? trans->paths + trans->sorted[idx]
  93                 : NULL;
  94 }
  95
  96 static inline struct btree_path *prev_btree_path(struct btree_trans *trans, struct btree_path *path)
  97 {
  98         EBUG_ON(path->sorted_idx >= trans->nr_sorted);
  99         return path->sorted_idx
 100                 ? trans->paths + trans->sorted[path->sorted_idx - 1]
 101                 : NULL;
 102 }
 103
 104 #define trans_for_each_path_inorder(_trans, _path, _i)                  \
 105         for (_i = 0;                                                    \
 106              ((_path) = (_trans)->paths + trans->sorted[_i]), (_i) < (_trans)->nr_sorted;\
 107              _i++)
 108
 109 static inline bool __path_has_node(const struct btree_path *path,
 110                                    const struct btree *b)
 111 {
 112         return path->l[b->c.level].b == b &&
 113                 btree_node_lock_seq_matches(path, b, b->c.level);
 114 }
 115
 116 static inline struct btree_path *
 117 __trans_next_path_with_node(struct btree_trans *trans, struct btree *b,
 118                             unsigned idx)
 119 {
 120         struct btree_path *path = __trans_next_path(trans, idx);
 121
 122         while (path && !__path_has_node(path, b))
 123                 path = __trans_next_path(trans, path->idx + 1);
 124
 125         return path;
 126 }
 127
 128 #define trans_for_each_path_with_node(_trans, _b, _path)                \
 129         for (_path = __trans_next_path_with_node((_trans), (_b), 0);    \
 130              (_path);                                                   \
 131              _path = __trans_next_path_with_node((_trans), (_b),        \
 132                                                  (_path)->idx + 1))
 133
 134 struct btree_path *__bch2_btree_path_make_mut(struct btree_trans *, struct btree_path *,
 135                          bool, unsigned long);
 136
 137 static inline struct btree_path * __must_check
 138 bch2_btree_path_make_mut(struct btree_trans *trans,
 139                          struct btree_path *path, bool intent,
 140                          unsigned long ip)
 141 {
 142         if (path->ref > 1 || path->preserve)
 143                 path = __bch2_btree_path_make_mut(trans, path, intent, ip);
 144         path->should_be_locked = false;
 145         return path;
 146 }
 147
 148 struct btree_path * __must_check
 149 __bch2_btree_path_set_pos(struct btree_trans *, struct btree_path *,
 150                         struct bpos, bool, unsigned long, int);
 151
 152 static inline struct btree_path * __must_check
 153 bch2_btree_path_set_pos(struct btree_trans *trans,
 154                    struct btree_path *path, struct bpos new_pos,
 155                    bool intent, unsigned long ip)
 156 {
 157         int cmp = bpos_cmp(new_pos, path->pos);
 158
 159         return cmp
 160                 ? __bch2_btree_path_set_pos(trans, path, new_pos, intent, ip, cmp)
 161                 : path;
 162 }
 163
 164 int __must_check bch2_btree_path_traverse(struct btree_trans *,
 165                                           struct btree_path *, unsigned);
 166 struct btree_path *bch2_path_get(struct btree_trans *, enum btree_id, struct bpos,
 167                                  unsigned, unsigned, unsigned, unsigned long);
 168 struct bkey_s_c bch2_btree_path_peek_slot(struct btree_path *, struct bkey *);
 169
 170 struct bkey_i *bch2_btree_journal_peek_slot(struct btree_trans *,
 171                                         struct btree_iter *, struct bpos);
 172
 173 void bch2_btree_path_level_init(struct btree_trans *, struct btree_path *, struct btree *);
 174
 175 #ifdef CONFIG_BCACHEFS_DEBUG
 176 void bch2_trans_verify_paths(struct btree_trans *);
 177 void bch2_assert_pos_locked(struct btree_trans *, enum btree_id,
 178                             struct bpos, bool);
 179 #else
 180 static inline void bch2_trans_verify_paths(struct btree_trans *trans) {}
 181 static inline void bch2_assert_pos_locked(struct btree_trans *trans, enum btree_id id,
 182                                           struct bpos pos, bool key_cache) {}
 183 #endif
 184
 185 void bch2_btree_path_fix_key_modified(struct btree_trans *trans,
 186                                       struct btree *, struct bkey_packed *);
 187 void bch2_btree_node_iter_fix(struct btree_trans *trans, struct btree_path *,
 188                               struct btree *, struct btree_node_iter *,
 189                               struct bkey_packed *, unsigned, unsigned);
 190
 191 int bch2_btree_path_relock_intent(struct btree_trans *, struct btree_path *);
 192
 193 void bch2_path_put(struct btree_trans *, struct btree_path *, bool);
 194
 195 int bch2_trans_relock(struct btree_trans *);
 196 void bch2_trans_unlock(struct btree_trans *);
 197 bool bch2_trans_locked(struct btree_trans *);
 198
 199 static inline bool trans_was_restarted(struct btree_trans *trans, u32 restart_count)
 200 {
 201         return restart_count != trans->restart_count;
 202 }
 203
 204 void bch2_trans_verify_not_restarted(struct btree_trans *, u32);
 205
 206 __always_inline
 207 static inline int btree_trans_restart_nounlock(struct btree_trans *trans, int err)
 208 {
 209         BUG_ON(err <= 0);
 210         BUG_ON(!bch2_err_matches(err, BCH_ERR_transaction_restart));
 211
 212         trans->restarted = err;
 213         return -err;
 214 }
 215
 216 __always_inline
 217 static inline int btree_trans_restart(struct btree_trans *trans, int err)
 218 {
 219         btree_trans_restart_nounlock(trans, err);
 220         return -err;
 221 }
 222
 223 bool bch2_btree_node_upgrade(struct btree_trans *,
 224                              struct btree_path *, unsigned);
 225
 226 void __bch2_btree_path_downgrade(struct btree_trans *, struct btree_path *, unsigned);
 227
 228 static inline void bch2_btree_path_downgrade(struct btree_trans *trans,
 229                                              struct btree_path *path)
 230 {
 231         unsigned new_locks_want = path->level + !!path->intent_ref;
 232
 233         if (path->locks_want > new_locks_want)
 234                 __bch2_btree_path_downgrade(trans, path, new_locks_want);
 235 }
 236
 237 void bch2_trans_downgrade(struct btree_trans *);
 238
 239 void bch2_trans_node_add(struct btree_trans *trans, struct btree *);
 240 void bch2_trans_node_reinit_iter(struct btree_trans *, struct btree *);
 241
 242 int __must_check __bch2_btree_iter_traverse(struct btree_iter *iter);
 243 int __must_check bch2_btree_iter_traverse(struct btree_iter *);
 244
 245 struct btree *bch2_btree_iter_peek_node(struct btree_iter *);
 246 struct btree *bch2_btree_iter_next_node(struct btree_iter *);
 247
 248 struct bkey_s_c bch2_btree_iter_peek_upto(struct btree_iter *, struct bpos);
 249 struct bkey_s_c bch2_btree_iter_next(struct btree_iter *);
 250
 251 struct bkey_s_c bch2_btree_iter_peek_all_levels(struct btree_iter *);
 252
 253 static inline struct bkey_s_c bch2_btree_iter_peek(struct btree_iter *iter)
 254 {
 255         return bch2_btree_iter_peek_upto(iter, SPOS_MAX);
 256 }
 257
 258 struct bkey_s_c bch2_btree_iter_peek_prev(struct btree_iter *);
 259 struct bkey_s_c bch2_btree_iter_prev(struct btree_iter *);
 260
 261 struct bkey_s_c bch2_btree_iter_peek_slot(struct btree_iter *);
 262 struct bkey_s_c bch2_btree_iter_next_slot(struct btree_iter *);
 263 struct bkey_s_c bch2_btree_iter_prev_slot(struct btree_iter *);
 264
 265 bool bch2_btree_iter_advance(struct btree_iter *);
 266 bool bch2_btree_iter_rewind(struct btree_iter *);
 267
 268 static inline void __bch2_btree_iter_set_pos(struct btree_iter *iter, struct bpos new_pos)
 269 {
 270         iter->k.type = KEY_TYPE_deleted;
 271         iter->k.p.inode         = iter->pos.inode       = new_pos.inode;
 272         iter->k.p.offset        = iter->pos.offset      = new_pos.offset;
 273         iter->k.p.snapshot      = iter->pos.snapshot    = new_pos.snapshot;
 274         iter->k.size = 0;
 275 }
 276
 277 static inline void bch2_btree_iter_set_pos(struct btree_iter *iter, struct bpos new_pos)
 278 {
 279         if (unlikely(iter->update_path))
 280                 bch2_path_put(iter->trans, iter->update_path,
 281                               iter->flags & BTREE_ITER_INTENT);
 282         iter->update_path = NULL;
 283
 284         if (!(iter->flags & BTREE_ITER_ALL_SNAPSHOTS))
 285                 new_pos.snapshot = iter->snapshot;
 286
 287         __bch2_btree_iter_set_pos(iter, new_pos);
 288 }
 289
 290 static inline void bch2_btree_iter_set_pos_to_extent_start(struct btree_iter *iter)
 291 {
 292         BUG_ON(!(iter->flags & BTREE_ITER_IS_EXTENTS));
 293         iter->pos = bkey_start_pos(&iter->k);
 294 }
 295
 296 static inline void bch2_btree_iter_set_snapshot(struct btree_iter *iter, u32 snapshot)
 297 {
 298         struct bpos pos = iter->pos;
 299
 300         iter->snapshot = snapshot;
 301         pos.snapshot = snapshot;
 302         bch2_btree_iter_set_pos(iter, pos);
 303 }
 304
 305 void bch2_trans_iter_exit(struct btree_trans *, struct btree_iter *);
 306
 307 static inline unsigned __bch2_btree_iter_flags(struct btree_trans *trans,
 308                                                unsigned btree_id,
 309                                                unsigned flags)
 310 {
 311         if (flags & BTREE_ITER_ALL_LEVELS)
 312                 flags |= BTREE_ITER_ALL_SNAPSHOTS|__BTREE_ITER_ALL_SNAPSHOTS;
 313
 314         if (!(flags & (BTREE_ITER_ALL_SNAPSHOTS|BTREE_ITER_NOT_EXTENTS)) &&
 315             btree_node_type_is_extents(btree_id))
 316                 flags |= BTREE_ITER_IS_EXTENTS;
 317
 318         if (!(flags & __BTREE_ITER_ALL_SNAPSHOTS) &&
 319             !btree_type_has_snapshots(btree_id))
 320                 flags &= ~BTREE_ITER_ALL_SNAPSHOTS;
 321
 322         if (!(flags & BTREE_ITER_ALL_SNAPSHOTS) &&
 323             btree_type_has_snapshots(btree_id))
 324                 flags |= BTREE_ITER_FILTER_SNAPSHOTS;
 325
 326         if (trans->journal_replay_not_finished)
 327                 flags |= BTREE_ITER_WITH_JOURNAL;
 328
 329         return flags;
 330 }
 331
 332 static inline unsigned bch2_btree_iter_flags(struct btree_trans *trans,
 333                                              unsigned btree_id,
 334                                              unsigned flags)
 335 {
 336         if (!btree_id_cached(trans->c, btree_id)) {
 337                 flags &= ~BTREE_ITER_CACHED;
 338                 flags &= ~BTREE_ITER_WITH_KEY_CACHE;
 339         } else if (!(flags & BTREE_ITER_CACHED))
 340                 flags |= BTREE_ITER_WITH_KEY_CACHE;
 341
 342         return __bch2_btree_iter_flags(trans, btree_id, flags);
 343 }
 344
 345 static inline void bch2_trans_iter_init_common(struct btree_trans *trans,
 346                                           struct btree_iter *iter,
 347                                           unsigned btree_id, struct bpos pos,
 348                                           unsigned locks_want,
 349                                           unsigned depth,
 350                                           unsigned flags,
 351                                           unsigned long ip)
 352 {
 353         memset(iter, 0, sizeof(*iter));
 354         iter->trans     = trans;
 355         iter->btree_id  = btree_id;
 356         iter->flags     = flags;
 357         iter->snapshot  = pos.snapshot;
 358         iter->pos       = pos;
 359         iter->k.p       = pos;
 360
 361 #ifdef CONFIG_BCACHEFS_DEBUG
 362         iter->ip_allocated = ip;
 363 #endif
 364         iter->path = bch2_path_get(trans, btree_id, iter->pos,
 365                                    locks_want, depth, flags, ip);
 366 }
 367
 368 void bch2_trans_iter_init_outlined(struct btree_trans *, struct btree_iter *,
 369                           unsigned, struct bpos, unsigned);
 370
 371 static inline void bch2_trans_iter_init(struct btree_trans *trans,
 372                           struct btree_iter *iter,
 373                           unsigned btree_id, struct bpos pos,
 374                           unsigned flags)
 375 {
 376         if (__builtin_constant_p(btree_id) &&
 377             __builtin_constant_p(flags))
 378                 bch2_trans_iter_init_common(trans, iter, btree_id, pos, 0, 0,
 379                                 bch2_btree_iter_flags(trans, btree_id, flags),
 380                                 _THIS_IP_);
 381         else
 382                 bch2_trans_iter_init_outlined(trans, iter, btree_id, pos, flags);
 383 }
 384
 385 void bch2_trans_node_iter_init(struct btree_trans *, struct btree_iter *,
 386                                enum btree_id, struct bpos,
 387                                unsigned, unsigned, unsigned);
 388 void bch2_trans_copy_iter(struct btree_iter *, struct btree_iter *);
 389
 390 static inline void set_btree_iter_dontneed(struct btree_iter *iter)
 391 {
 392         if (!iter->trans->restarted)
 393                 iter->path->preserve = false;
 394 }
 395
 396 void *__bch2_trans_kmalloc(struct btree_trans *, size_t);
 397
 398 static inline void *bch2_trans_kmalloc(struct btree_trans *trans, size_t size)
 399 {
 400         size = roundup(size, 8);
 401
 402         if (likely(trans->mem_top + size <= trans->mem_bytes)) {
 403                 void *p = trans->mem + trans->mem_top;
 404
 405                 trans->mem_top += size;
 406                 memset(p, 0, size);
 407                 return p;
 408         } else {
 409                 return __bch2_trans_kmalloc(trans, size);
 410         }
 411 }
 412
 413 static inline void *bch2_trans_kmalloc_nomemzero(struct btree_trans *trans, size_t size)
 414 {
 415         size = roundup(size, 8);
 416
 417         if (likely(trans->mem_top + size <= trans->mem_bytes)) {
 418                 void *p = trans->mem + trans->mem_top;
 419
 420                 trans->mem_top += size;
 421                 return p;
 422         } else {
 423                 return __bch2_trans_kmalloc(trans, size);
 424         }
 425 }
 426
 427 static inline struct bkey_i *bch2_bkey_make_mut(struct btree_trans *trans, struct bkey_s_c k)
 428 {
 429         struct bkey_i *mut = bch2_trans_kmalloc_nomemzero(trans, bkey_bytes(k.k));
 430
 431         if (!IS_ERR(mut))
 432                 bkey_reassemble(mut, k);
 433         return mut;
 434 }
 435
 436 static inline struct bkey_i *bch2_bkey_get_mut(struct btree_trans *trans,
 437                                                struct btree_iter *iter)
 438 {
 439         struct bkey_s_c k = bch2_btree_iter_peek_slot(iter);
 440
 441         return unlikely(IS_ERR(k.k))
 442                 ? ERR_CAST(k.k)
 443                 : bch2_bkey_make_mut(trans, k);
 444 }
 445
 446 #define bch2_bkey_get_mut_typed(_trans, _iter, _type)                   \
 447 ({                                                                      \
 448         struct bkey_i *_k = bch2_bkey_get_mut(_trans, _iter);           \
 449         struct bkey_i_##_type *_ret;                                    \
 450                                                                         \
 451         if (IS_ERR(_k))                                                 \
 452                 _ret = ERR_CAST(_k);                                    \
 453         else if (unlikely(_k->k.type != KEY_TYPE_##_type))              \
 454                 _ret = ERR_PTR(-ENOENT);                                \
 455         else                                                            \
 456                 _ret = bkey_i_to_##_type(_k);                           \
 457         _ret;                                                           \
 458 })
 459
 460 #define bch2_bkey_alloc(_trans, _iter, _type)                           \
 461 ({                                                                      \
 462         struct bkey_i_##_type *_k = bch2_trans_kmalloc(_trans, sizeof(*_k));\
 463         if (!IS_ERR(_k)) {                                              \
 464                 bkey_##_type##_init(&_k->k_i);                          \
 465                 _k->k.p = (_iter)->pos;                                 \
 466         }                                                               \
 467         _k;                                                             \
 468 })
 469
 470 u32 bch2_trans_begin(struct btree_trans *);
 471
 472 static inline struct btree *
 473 __btree_iter_peek_node_and_restart(struct btree_trans *trans, struct btree_iter *iter)
 474 {
 475         struct btree *b;
 476
 477         while (b = bch2_btree_iter_peek_node(iter),
 478                bch2_err_matches(PTR_ERR_OR_ZERO(b), BCH_ERR_transaction_restart))
 479                 bch2_trans_begin(trans);
 480
 481         return b;
 482 }
 483
 484 /*
 485  * XXX
 486  * this does not handle transaction restarts from bch2_btree_iter_next_node()
 487  * correctly
 488  */
 489 #define __for_each_btree_node(_trans, _iter, _btree_id, _start,         \
 490                               _locks_want, _depth, _flags, _b, _ret)    \
 491         for (bch2_trans_node_iter_init((_trans), &(_iter), (_btree_id), \
 492                                 _start, _locks_want, _depth, _flags);   \
 493              (_b) = __btree_iter_peek_node_and_restart((_trans), &(_iter)),\
 494              !((_ret) = PTR_ERR_OR_ZERO(_b)) && (_b);                   \
 495              (_b) = bch2_btree_iter_next_node(&(_iter)))
 496
 497 #define for_each_btree_node(_trans, _iter, _btree_id, _start,           \
 498                             _flags, _b, _ret)                           \
 499         __for_each_btree_node(_trans, _iter, _btree_id, _start,         \
 500                               0, 0, _flags, _b, _ret)
 501
 502 static inline int bkey_err(struct bkey_s_c k)
 503 {
 504         return PTR_ERR_OR_ZERO(k.k);
 505 }
 506
 507 static inline struct bkey_s_c bch2_btree_iter_peek_prev_type(struct btree_iter *iter,
 508                                                              unsigned flags)
 509 {
 510         BUG_ON(flags & BTREE_ITER_ALL_LEVELS);
 511
 512         return  flags & BTREE_ITER_SLOTS      ? bch2_btree_iter_peek_slot(iter) :
 513                                                 bch2_btree_iter_peek_prev(iter);
 514 }
 515
 516 static inline struct bkey_s_c bch2_btree_iter_peek_type(struct btree_iter *iter,
 517                                                         unsigned flags)
 518 {
 519         return  flags & BTREE_ITER_ALL_LEVELS ? bch2_btree_iter_peek_all_levels(iter) :
 520                 flags & BTREE_ITER_SLOTS      ? bch2_btree_iter_peek_slot(iter) :
 521                                                 bch2_btree_iter_peek(iter);
 522 }
 523
 524 static inline struct bkey_s_c bch2_btree_iter_peek_upto_type(struct btree_iter *iter,
 525                                                              struct bpos end,
 526                                                              unsigned flags)
 527 {
 528         if (!(flags & BTREE_ITER_SLOTS))
 529                 return bch2_btree_iter_peek_upto(iter, end);
 530
 531         if (bkey_gt(iter->pos, end))
 532                 return bkey_s_c_null;
 533
 534         return bch2_btree_iter_peek_slot(iter);
 535 }
 536
 537 static inline int btree_trans_too_many_iters(struct btree_trans *trans)
 538 {
 539         if (hweight64(trans->paths_allocated) > BTREE_ITER_MAX - 8) {
 540                 trace_and_count(trans->c, trans_restart_too_many_iters, trans, _THIS_IP_);
 541                 return btree_trans_restart(trans, BCH_ERR_transaction_restart_too_many_iters);
 542         }
 543
 544         return 0;
 545 }
 546
 547 static inline struct bkey_s_c
 548 __bch2_btree_iter_peek_and_restart(struct btree_trans *trans,
 549                                    struct btree_iter *iter, unsigned flags)
 550 {
 551         struct bkey_s_c k;
 552
 553         while (btree_trans_too_many_iters(trans) ||
 554                (k = bch2_btree_iter_peek_type(iter, flags),
 555                 bch2_err_matches(bkey_err(k), BCH_ERR_transaction_restart)))
 556                 bch2_trans_begin(trans);
 557
 558         return k;
 559 }
 560
 561 #define lockrestart_do(_trans, _do)                                     \
 562 ({                                                                      \
 563         u32 _restart_count;                                             \
 564         int _ret;                                                       \
 565                                                                         \
 566         do {                                                            \
 567                 _restart_count = bch2_trans_begin(_trans);              \
 568                 _ret = (_do);                                           \
 569         } while (bch2_err_matches(_ret, BCH_ERR_transaction_restart));  \
 570                                                                         \
 571         if (!_ret)                                                      \
 572                 bch2_trans_verify_not_restarted(_trans, _restart_count);\
 573                                                                         \
 574         _ret;                                                           \
 575 })
 576
 577 /*
 578  * nested_lockrestart_do(), nested_commit_do():
 579  *
 580  * These are like lockrestart_do() and commit_do(), with two differences:
 581  *
 582  *  - We don't call bch2_trans_begin() unless we had a transaction restart
 583  *  - We return -BCH_ERR_transaction_restart_nested if we succeeded after a
 584  *  transaction restart
 585  */
 586 #define nested_lockrestart_do(_trans, _do)                              \
 587 ({                                                                      \
 588         u32 _restart_count, _orig_restart_count;                        \
 589         int _ret;                                                       \
 590                                                                         \
 591         _restart_count = _orig_restart_count = (_trans)->restart_count; \
 592                                                                         \
 593         while (bch2_err_matches(_ret = (_do), BCH_ERR_transaction_restart))\
 594                 _restart_count = bch2_trans_begin(_trans);              \
 595                                                                         \
 596         if (!_ret)                                                      \
 597                 bch2_trans_verify_not_restarted(_trans, _restart_count);\
 598                                                                         \
 599         if (!_ret && trans_was_restarted(_trans, _orig_restart_count))  \
 600                 _ret = -BCH_ERR_transaction_restart_nested;             \
 601                                                                         \
 602         _ret;                                                           \
 603 })
 604
 605 #define for_each_btree_key2(_trans, _iter, _btree_id,                   \
 606                             _start, _flags, _k, _do)                    \
 607 ({                                                                      \
 608         int _ret = 0;                                                   \
 609                                                                         \
 610         bch2_trans_iter_init((_trans), &(_iter), (_btree_id),           \
 611                              (_start), (_flags));                       \
 612                                                                         \
 613         while (1) {                                                     \
 614                 u32 _restart_count = bch2_trans_begin(_trans);          \
 615                                                                         \
 616                 _ret = 0;                                               \
 617                 (_k) = bch2_btree_iter_peek_type(&(_iter), (_flags));   \
 618                 if (!(_k).k)                                            \
 619                         break;                                          \
 620                                                                         \
 621                 _ret = bkey_err(_k) ?: (_do);                           \
 622                 if (bch2_err_matches(_ret, BCH_ERR_transaction_restart))\
 623                         continue;                                       \
 624                 if (_ret)                                               \
 625                         break;                                          \
 626                 bch2_trans_verify_not_restarted(_trans, _restart_count);\
 627                 if (!bch2_btree_iter_advance(&(_iter)))                 \
 628                         break;                                          \
 629         }                                                               \
 630                                                                         \
 631         bch2_trans_iter_exit((_trans), &(_iter));                       \
 632         _ret;                                                           \
 633 })
 634
 635 #define for_each_btree_key2_upto(_trans, _iter, _btree_id,              \
 636                             _start, _end, _flags, _k, _do)              \
 637 ({                                                                      \
 638         int _ret = 0;                                                   \
 639                                                                         \
 640         bch2_trans_iter_init((_trans), &(_iter), (_btree_id),           \
 641                              (_start), (_flags));                       \
 642                                                                         \
 643         while (1) {                                                     \
 644                 u32 _restart_count = bch2_trans_begin(_trans);          \
 645                                                                         \
 646                 _ret = 0;                                               \
 647                 (_k) = bch2_btree_iter_peek_upto_type(&(_iter), _end, (_flags));\
 648                 if (!(_k).k)                                            \
 649                         break;                                          \
 650                                                                         \
 651                 _ret = bkey_err(_k) ?: (_do);                           \
 652                 if (bch2_err_matches(_ret, BCH_ERR_transaction_restart))\
 653                         continue;                                       \
 654                 if (_ret)                                               \
 655                         break;                                          \
 656                 bch2_trans_verify_not_restarted(_trans, _restart_count);\
 657                 if (!bch2_btree_iter_advance(&(_iter)))                 \
 658                         break;                                          \
 659         }                                                               \
 660                                                                         \
 661         bch2_trans_iter_exit((_trans), &(_iter));                       \
 662         _ret;                                                           \
 663 })
 664
 665 #define for_each_btree_key_reverse(_trans, _iter, _btree_id,            \
 666                                    _start, _flags, _k, _do)             \
 667 ({                                                                      \
 668         int _ret = 0;                                                   \
 669                                                                         \
 670         bch2_trans_iter_init((_trans), &(_iter), (_btree_id),           \
 671                              (_start), (_flags));                       \
 672                                                                         \
 673         while (1) {                                                     \
 674                 u32 _restart_count = bch2_trans_begin(_trans);          \
 675                 (_k) = bch2_btree_iter_peek_prev_type(&(_iter), (_flags));\
 676                 if (!(_k).k) {                                          \
 677                         _ret = 0;                                       \
 678                         break;                                          \
 679                 }                                                       \
 680                                                                         \
 681                 _ret = bkey_err(_k) ?: (_do);                           \
 682                 if (bch2_err_matches(_ret, BCH_ERR_transaction_restart))\
 683                         continue;                                       \
 684                 if (_ret)                                               \
 685                         break;                                          \
 686                 bch2_trans_verify_not_restarted(_trans, _restart_count);\
 687                 if (!bch2_btree_iter_rewind(&(_iter)))                  \
 688                         break;                                          \
 689         }                                                               \
 690                                                                         \
 691         bch2_trans_iter_exit((_trans), &(_iter));                       \
 692         _ret;                                                           \
 693 })
 694
 695 #define for_each_btree_key_commit(_trans, _iter, _btree_id,             \
 696                                   _start, _iter_flags, _k,              \
 697                                   _disk_res, _journal_seq, _commit_flags,\
 698                                   _do)                                  \
 699         for_each_btree_key2(_trans, _iter, _btree_id, _start, _iter_flags, _k,\
 700                             (_do) ?: bch2_trans_commit(_trans, (_disk_res),\
 701                                         (_journal_seq), (_commit_flags)))
 702
 703 #define for_each_btree_key_upto_commit(_trans, _iter, _btree_id,        \
 704                                   _start, _end, _iter_flags, _k,        \
 705                                   _disk_res, _journal_seq, _commit_flags,\
 706                                   _do)                                  \
 707         for_each_btree_key2_upto(_trans, _iter, _btree_id, _start, _end, _iter_flags, _k,\
 708                             (_do) ?: bch2_trans_commit(_trans, (_disk_res),\
 709                                         (_journal_seq), (_commit_flags)))
 710
 711 #define for_each_btree_key(_trans, _iter, _btree_id,                    \
 712                            _start, _flags, _k, _ret)                    \
 713         for (bch2_trans_iter_init((_trans), &(_iter), (_btree_id),      \
 714                                   (_start), (_flags));                  \
 715              (_k) = __bch2_btree_iter_peek_and_restart((_trans), &(_iter), _flags),\
 716              !((_ret) = bkey_err(_k)) && (_k).k;                        \
 717              bch2_btree_iter_advance(&(_iter)))
 718
 719 #define for_each_btree_key_norestart(_trans, _iter, _btree_id,          \
 720                            _start, _flags, _k, _ret)                    \
 721         for (bch2_trans_iter_init((_trans), &(_iter), (_btree_id),      \
 722                                   (_start), (_flags));                  \
 723              (_k) = bch2_btree_iter_peek_type(&(_iter), _flags),        \
 724              !((_ret) = bkey_err(_k)) && (_k).k;                        \
 725              bch2_btree_iter_advance(&(_iter)))
 726
 727 #define for_each_btree_key_upto_norestart(_trans, _iter, _btree_id,     \
 728                            _start, _end, _flags, _k, _ret)              \
 729         for (bch2_trans_iter_init((_trans), &(_iter), (_btree_id),      \
 730                                   (_start), (_flags));                  \
 731              (_k) = bch2_btree_iter_peek_upto_type(&(_iter), _end, _flags),\
 732              !((_ret) = bkey_err(_k)) && (_k).k;                        \
 733              bch2_btree_iter_advance(&(_iter)))
 734
 735 #define for_each_btree_key_continue(_trans, _iter, _flags, _k, _ret)    \
 736         for (;                                                          \
 737              (_k) = __bch2_btree_iter_peek_and_restart((_trans), &(_iter), _flags),\
 738              !((_ret) = bkey_err(_k)) && (_k).k;                        \
 739              bch2_btree_iter_advance(&(_iter)))
 740
 741 #define for_each_btree_key_continue_norestart(_iter, _flags, _k, _ret)  \
 742         for (;                                                          \
 743              (_k) = bch2_btree_iter_peek_type(&(_iter), _flags),        \
 744              !((_ret) = bkey_err(_k)) && (_k).k;                        \
 745              bch2_btree_iter_advance(&(_iter)))
 746
 747 #define for_each_btree_key_upto_continue_norestart(_iter, _end, _flags, _k, _ret)\
 748         for (;                                                                  \
 749              (_k) = bch2_btree_iter_peek_upto_type(&(_iter), _end, _flags),     \
 750              !((_ret) = bkey_err(_k)) && (_k).k;                                \
 751              bch2_btree_iter_advance(&(_iter)))
 752
 753 /* new multiple iterator interface: */
 754
 755 void bch2_trans_updates_to_text(struct printbuf *, struct btree_trans *);
 756 void bch2_btree_path_to_text(struct printbuf *, struct btree_path *);
 757 void bch2_trans_paths_to_text(struct printbuf *, struct btree_trans *);
 758 void bch2_dump_trans_updates(struct btree_trans *);
 759 void bch2_dump_trans_paths_updates(struct btree_trans *);
 760 void __bch2_trans_init(struct btree_trans *, struct bch_fs *, unsigned);
 761 void bch2_trans_exit(struct btree_trans *);
 762
 763 extern const char *bch2_btree_transaction_fns[BCH_TRANSACTIONS_NR];
 764 unsigned bch2_trans_get_fn_idx(const char *);
 765
 766 #define bch2_trans_init(_trans, _c, _nr_iters, _mem)                    \
 767 do {                                                                    \
 768         static unsigned trans_fn_idx;                                   \
 769                                                                         \
 770         if (unlikely(!trans_fn_idx))                                    \
 771                 trans_fn_idx = bch2_trans_get_fn_idx(__func__);         \
 772                                                                         \
 773         __bch2_trans_init(_trans, _c, trans_fn_idx);                    \
 774 } while (0)
 775
 776 void bch2_btree_trans_to_text(struct printbuf *, struct btree_trans *);
 777
 778 void bch2_fs_btree_iter_exit(struct bch_fs *);
 779 int bch2_fs_btree_iter_init(struct bch_fs *);
 780
 781 #endif /* _BCACHEFS_BTREE_ITER_H */