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

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include "bcachefs.h"
   3 #include "bbpos.h"
   4 #include "alloc_background.h"
   5 #include "backpointers.h"
   6 #include "btree_cache.h"
   7 #include "btree_update.h"
   8 #include "error.h"
   9
  10 #include <linux/mm.h>
  11
  12 #define MAX_EXTENT_COMPRESS_RATIO_SHIFT         10
  13
  14 /*
  15  * Convert from pos in backpointer btree to pos of corresponding bucket in alloc
  16  * btree:
  17  */
  18 static inline struct bpos bp_pos_to_bucket(const struct bch_fs *c,
  19                                            struct bpos bp_pos)
  20 {
  21         struct bch_dev *ca = bch_dev_bkey_exists(c, bp_pos.inode);
  22         u64 bucket_sector = bp_pos.offset >> MAX_EXTENT_COMPRESS_RATIO_SHIFT;
  23
  24         return POS(bp_pos.inode, sector_to_bucket(ca, bucket_sector));
  25 }
  26
  27 /*
  28  * Convert from pos in alloc btree + bucket offset to pos in backpointer btree:
  29  */
  30 static inline struct bpos bucket_pos_to_bp(const struct bch_fs *c,
  31                                            struct bpos bucket,
  32                                            u64 bucket_offset)
  33 {
  34         struct bch_dev *ca = bch_dev_bkey_exists(c, bucket.inode);
  35         struct bpos ret;
  36
  37         ret = POS(bucket.inode,
  38                   (bucket_to_sector(ca, bucket.offset) <<
  39                    MAX_EXTENT_COMPRESS_RATIO_SHIFT) + bucket_offset);
  40
  41         BUG_ON(bpos_cmp(bucket, bp_pos_to_bucket(c, ret)));
  42
  43         return ret;
  44 }
  45
  46 void bch2_extent_ptr_to_bp(struct bch_fs *c,
  47                            enum btree_id btree_id, unsigned level,
  48                            struct bkey_s_c k, struct extent_ptr_decoded p,
  49                            struct bpos *bucket_pos, struct bch_backpointer *bp)
  50 {
  51         enum bch_data_type data_type = level ? BCH_DATA_btree : BCH_DATA_user;
  52         s64 sectors = level ? btree_sectors(c) : k.k->size;
  53         u32 bucket_offset;
  54
  55         *bucket_pos = PTR_BUCKET_POS_OFFSET(c, &p.ptr, &bucket_offset);
  56         *bp = (struct bch_backpointer) {
  57                 .btree_id       = btree_id,
  58                 .level          = level,
  59                 .data_type      = data_type,
  60                 .bucket_offset  = ((u64) bucket_offset << MAX_EXTENT_COMPRESS_RATIO_SHIFT) +
  61                         p.crc.offset,
  62                 .bucket_len     = ptr_disk_sectors(sectors, p),
  63                 .pos            = k.k->p,
  64         };
  65 }
  66
  67 static bool extent_matches_bp(struct bch_fs *c,
  68                               enum btree_id btree_id, unsigned level,
  69                               struct bkey_s_c k,
  70                               struct bpos bucket,
  71                               struct bch_backpointer bp)
  72 {
  73         struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
  74         const union bch_extent_entry *entry;
  75         struct extent_ptr_decoded p;
  76
  77         bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
  78                 struct bpos bucket2;
  79                 struct bch_backpointer bp2;
  80
  81                 if (p.ptr.cached)
  82                         continue;
  83
  84                 bch2_extent_ptr_to_bp(c, btree_id, level, k, p,
  85                                       &bucket2, &bp2);
  86                 if (!bpos_cmp(bucket, bucket2) &&
  87                     !memcmp(&bp, &bp2, sizeof(bp)))
  88                         return true;
  89         }
  90
  91         return false;
  92 }
  93
  94 int bch2_backpointer_invalid(const struct bch_fs *c, struct bkey_s_c k,
  95                              int rw, struct printbuf *err)
  96 {
  97         struct bkey_s_c_backpointer bp = bkey_s_c_to_backpointer(k);
  98         struct bpos bucket = bp_pos_to_bucket(c, bp.k->p);
  99
 100         if (bkey_val_bytes(bp.k) < sizeof(*bp.v)) {
 101                 prt_str(err, "incorrect value size");
 102                 return -EINVAL;
 103         }
 104
 105         if (bpos_cmp(bp.k->p, bucket_pos_to_bp(c, bucket, bp.v->bucket_offset))) {
 106                 prt_str(err, "backpointer at wrong pos");
 107                 return -EINVAL;
 108         }
 109
 110         return 0;
 111 }
 112
 113 void bch2_backpointer_to_text(struct printbuf *out, const struct bch_backpointer *bp)
 114 {
 115         prt_printf(out, "btree=%s l=%u offset=%llu:%u len=%u pos=",
 116                bch2_btree_ids[bp->btree_id],
 117                bp->level,
 118                (u64) (bp->bucket_offset >> MAX_EXTENT_COMPRESS_RATIO_SHIFT),
 119                (u32) bp->bucket_offset & ~(~0U << MAX_EXTENT_COMPRESS_RATIO_SHIFT),
 120                bp->bucket_len);
 121         bch2_bpos_to_text(out, bp->pos);
 122 }
 123
 124 void bch2_backpointer_k_to_text(struct printbuf *out, struct bch_fs *c, struct bkey_s_c k)
 125 {
 126         bch2_backpointer_to_text(out, bkey_s_c_to_backpointer(k).v);
 127 }
 128
 129 void bch2_backpointer_swab(struct bkey_s k)
 130 {
 131         struct bkey_s_backpointer bp = bkey_s_to_backpointer(k);
 132
 133         bp.v->bucket_offset     = swab32(bp.v->bucket_offset);
 134         bp.v->bucket_len        = swab32(bp.v->bucket_len);
 135         bch2_bpos_swab(&bp.v->pos);
 136 }
 137
 138 #define BACKPOINTER_OFFSET_MAX  ((1ULL << 40) - 1)
 139
 140 static inline int backpointer_cmp(struct bch_backpointer l, struct bch_backpointer r)
 141 {
 142         return cmp_int(l.bucket_offset, r.bucket_offset);
 143 }
 144
 145 static int bch2_backpointer_del_by_offset(struct btree_trans *trans,
 146                                           struct bpos bucket,
 147                                           u64 bp_offset,
 148                                           struct bch_backpointer bp)
 149 {
 150         struct bch_fs *c = trans->c;
 151         struct btree_iter iter;
 152         struct bkey_s_c k;
 153         int ret;
 154
 155         if (bp_offset < BACKPOINTER_OFFSET_MAX) {
 156                 struct bch_backpointer *bps;
 157                 struct bkey_i_alloc_v4 *a;
 158                 unsigned i, nr;
 159
 160                 bch2_trans_iter_init(trans, &iter, BTREE_ID_alloc,
 161                                      bucket,
 162                                      BTREE_ITER_INTENT|
 163                                      BTREE_ITER_SLOTS|
 164                                      BTREE_ITER_WITH_UPDATES);
 165                 k = bch2_btree_iter_peek_slot(&iter);
 166                 ret = bkey_err(k);
 167                 if (ret)
 168                         goto err;
 169
 170                 if (k.k->type != KEY_TYPE_alloc_v4) {
 171                         ret = -ENOENT;
 172                         goto err;
 173                 }
 174
 175                 a = bch2_alloc_to_v4_mut(trans, k);
 176                 ret = PTR_ERR_OR_ZERO(a);
 177                 if (ret)
 178                         goto err;
 179                 bps = alloc_v4_backpointers(&a->v);
 180                 nr = BCH_ALLOC_V4_NR_BACKPOINTERS(&a->v);
 181
 182                 for (i = 0; i < nr; i++) {
 183                         if (bps[i].bucket_offset == bp_offset)
 184                                 goto found;
 185                         if (bps[i].bucket_offset > bp_offset)
 186                                 break;
 187                 }
 188
 189                 ret = -ENOENT;
 190                 goto err;
 191 found:
 192                 if (memcmp(&bps[i], &bp, sizeof(bp))) {
 193                         ret = -ENOENT;
 194                         goto err;
 195                 }
 196                 array_remove_item(bps, nr, i);
 197                 SET_BCH_ALLOC_V4_NR_BACKPOINTERS(&a->v, nr);
 198                 set_alloc_v4_u64s(a);
 199                 ret = bch2_trans_update(trans, &iter, &a->k_i, 0);
 200         } else {
 201                 bp_offset -= BACKPOINTER_OFFSET_MAX;
 202
 203                 bch2_trans_iter_init(trans, &iter, BTREE_ID_backpointers,
 204                                      bucket_pos_to_bp(c, bucket, bp_offset),
 205                                      BTREE_ITER_INTENT|
 206                                      BTREE_ITER_SLOTS|
 207                                      BTREE_ITER_WITH_UPDATES);
 208                 k = bch2_btree_iter_peek_slot(&iter);
 209                 ret = bkey_err(k);
 210                 if (ret)
 211                         goto err;
 212
 213                 if (k.k->type != KEY_TYPE_backpointer ||
 214                     memcmp(bkey_s_c_to_backpointer(k).v, &bp, sizeof(bp))) {
 215                         ret = -ENOENT;
 216                         goto err;
 217                 }
 218
 219                 ret = bch2_btree_delete_at(trans, &iter, 0);
 220         }
 221 err:
 222         bch2_trans_iter_exit(trans, &iter);
 223         return ret;
 224 }
 225
 226 int bch2_bucket_backpointer_del(struct btree_trans *trans,
 227                                 struct bkey_i_alloc_v4 *a,
 228                                 struct bch_backpointer bp,
 229                                 struct bkey_s_c orig_k)
 230 {
 231         struct bch_fs *c = trans->c;
 232         struct bch_backpointer *bps = alloc_v4_backpointers(&a->v);
 233         unsigned i, nr = BCH_ALLOC_V4_NR_BACKPOINTERS(&a->v);
 234         struct btree_iter bp_iter;
 235         struct bkey_s_c k;
 236         int ret;
 237
 238         for (i = 0; i < nr; i++) {
 239                 int cmp = backpointer_cmp(bps[i], bp) ?:
 240                         memcmp(&bps[i], &bp, sizeof(bp));
 241                 if (!cmp)
 242                         goto found;
 243                 if (cmp >= 0)
 244                         break;
 245         }
 246
 247         goto btree;
 248 found:
 249         array_remove_item(bps, nr, i);
 250         SET_BCH_ALLOC_V4_NR_BACKPOINTERS(&a->v, nr);
 251         set_alloc_v4_u64s(a);
 252         return 0;
 253 btree:
 254         bch2_trans_iter_init(trans, &bp_iter, BTREE_ID_backpointers,
 255                              bucket_pos_to_bp(c, a->k.p, bp.bucket_offset),
 256                              BTREE_ITER_INTENT|
 257                              BTREE_ITER_SLOTS|
 258                              BTREE_ITER_WITH_UPDATES);
 259         k = bch2_btree_iter_peek_slot(&bp_iter);
 260         ret = bkey_err(k);
 261         if (ret)
 262                 goto err;
 263
 264         if (k.k->type != KEY_TYPE_backpointer ||
 265             memcmp(bkey_s_c_to_backpointer(k).v, &bp, sizeof(bp))) {
 266                 struct printbuf buf = PRINTBUF;
 267
 268                 prt_printf(&buf, "backpointer not found when deleting");
 269                 prt_newline(&buf);
 270                 printbuf_indent_add(&buf, 2);
 271
 272                 prt_printf(&buf, "searching for ");
 273                 bch2_backpointer_to_text(&buf, &bp);
 274                 prt_newline(&buf);
 275
 276                 prt_printf(&buf, "got ");
 277                 bch2_bkey_val_to_text(&buf, c, k);
 278                 prt_newline(&buf);
 279
 280                 prt_str(&buf, "alloc ");
 281                 bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&a->k_i));
 282                 prt_newline(&buf);
 283
 284                 prt_printf(&buf, "for ");
 285                 bch2_bkey_val_to_text(&buf, c, orig_k);
 286
 287                 if (!test_bit(BCH_FS_CHECK_BACKPOINTERS_DONE, &c->flags)) {
 288                         bch_err(c, "%s", buf.buf);
 289                 } else {
 290                         ret = -EIO;
 291                         bch2_trans_inconsistent(trans, "%s", buf.buf);
 292                 }
 293                 printbuf_exit(&buf);
 294                 goto err;
 295         }
 296
 297         ret = bch2_btree_delete_at(trans, &bp_iter, 0);
 298 err:
 299         bch2_trans_iter_exit(trans, &bp_iter);
 300         return ret;
 301 }
 302
 303 int bch2_bucket_backpointer_add(struct btree_trans *trans,
 304                                 struct bkey_i_alloc_v4 *a,
 305                                 struct bch_backpointer bp,
 306                                 struct bkey_s_c orig_k)
 307 {
 308         struct bch_fs *c = trans->c;
 309         struct bch_dev *ca;
 310         struct bch_backpointer *bps = alloc_v4_backpointers(&a->v);
 311         unsigned i, nr = BCH_ALLOC_V4_NR_BACKPOINTERS(&a->v);
 312         struct bkey_i_backpointer *bp_k;
 313         struct btree_iter bp_iter;
 314         struct bkey_s_c k;
 315         int ret;
 316
 317         /* Check for duplicates: */
 318         for (i = 0; i < nr; i++) {
 319                 int cmp = backpointer_cmp(bps[i], bp);
 320                 if (cmp >= 0)
 321                         break;
 322         }
 323
 324         if ((i &&
 325              (bps[i - 1].bucket_offset +
 326               bps[i - 1].bucket_len > bp.bucket_offset)) ||
 327             (i < nr &&
 328              (bp.bucket_offset + bp.bucket_len > bps[i].bucket_offset))) {
 329                 struct printbuf buf = PRINTBUF;
 330
 331                 prt_printf(&buf, "overlapping backpointer found when inserting ");
 332                 bch2_backpointer_to_text(&buf, &bp);
 333                 prt_newline(&buf);
 334                 printbuf_indent_add(&buf, 2);
 335
 336                 prt_printf(&buf, "into ");
 337                 bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&a->k_i));
 338                 prt_newline(&buf);
 339
 340                 prt_printf(&buf, "for ");
 341                 bch2_bkey_val_to_text(&buf, c, orig_k);
 342
 343                 if (!test_bit(BCH_FS_CHECK_BACKPOINTERS_DONE, &c->flags))
 344                         bch_err(c, "%s", buf.buf);
 345                 else {
 346                         bch2_trans_inconsistent(trans, "%s", buf.buf);
 347                         printbuf_exit(&buf);
 348                         return -EIO;
 349                 }
 350         }
 351
 352         if (nr < BCH_ALLOC_V4_NR_BACKPOINTERS_MAX) {
 353                 array_insert_item(bps, nr, i, bp);
 354                 SET_BCH_ALLOC_V4_NR_BACKPOINTERS(&a->v, nr);
 355                 set_alloc_v4_u64s(a);
 356                 return 0;
 357         }
 358
 359         /* Overflow: use backpointer btree */
 360         bp_k = bch2_trans_kmalloc(trans, sizeof(*bp_k));
 361         ret = PTR_ERR_OR_ZERO(bp_k);
 362         if (ret)
 363                 return ret;
 364
 365         ca = bch_dev_bkey_exists(c, a->k.p.inode);
 366
 367         bkey_backpointer_init(&bp_k->k_i);
 368         bp_k->k.p = bucket_pos_to_bp(c, a->k.p, bp.bucket_offset);
 369         bp_k->v = bp;
 370
 371         bch2_trans_iter_init(trans, &bp_iter, BTREE_ID_backpointers, bp_k->k.p,
 372                              BTREE_ITER_INTENT|
 373                              BTREE_ITER_SLOTS|
 374                              BTREE_ITER_WITH_UPDATES);
 375         k = bch2_btree_iter_peek_slot(&bp_iter);
 376         ret = bkey_err(k);
 377         if (ret)
 378                 goto err;
 379
 380         if (k.k->type) {
 381                 struct printbuf buf = PRINTBUF;
 382
 383                 prt_printf(&buf, "existing btree backpointer key found when inserting ");
 384                 bch2_backpointer_to_text(&buf, &bp);
 385                 prt_newline(&buf);
 386                 printbuf_indent_add(&buf, 2);
 387
 388                 prt_printf(&buf, "found ");
 389                 bch2_bkey_val_to_text(&buf, c, k);
 390                 prt_newline(&buf);
 391
 392                 prt_printf(&buf, "for ");
 393                 bch2_bkey_val_to_text(&buf, c, orig_k);
 394
 395                 if (!test_bit(BCH_FS_CHECK_BACKPOINTERS_DONE, &c->flags))
 396                         bch_err(c, "%s", buf.buf);
 397                 else {
 398                         bch2_trans_inconsistent(trans, "%s", buf.buf);
 399                         printbuf_exit(&buf);
 400                         ret = -EIO;
 401                         goto err;
 402                 }
 403         }
 404
 405         ret = bch2_trans_update(trans, &bp_iter, &bp_k->k_i, 0);
 406 err:
 407         bch2_trans_iter_exit(trans, &bp_iter);
 408         return ret;
 409 }
 410
 411 /*
 412  * Find the next backpointer >= *bp_offset:
 413  */
 414 int bch2_get_next_backpointer(struct btree_trans *trans,
 415                               struct bpos bucket, int gen,
 416                               u64 *bp_offset,
 417                               struct bch_backpointer *dst)
 418 {
 419         struct bch_fs *c = trans->c;
 420         struct bpos bp_pos, bp_end_pos;
 421         struct btree_iter alloc_iter, bp_iter = { NULL };
 422         struct bkey_s_c k;
 423         struct bkey_s_c_alloc_v4 a;
 424         size_t i;
 425         int ret;
 426
 427         if (*bp_offset == U64_MAX)
 428                 return 0;
 429
 430         bp_pos = bucket_pos_to_bp(c, bucket,
 431                                   max(*bp_offset, BACKPOINTER_OFFSET_MAX) - BACKPOINTER_OFFSET_MAX);
 432         bp_end_pos = bucket_pos_to_bp(c, bpos_nosnap_successor(bucket), 0);
 433
 434         bch2_trans_iter_init(trans, &alloc_iter, BTREE_ID_alloc,
 435                              bucket, BTREE_ITER_CACHED);
 436         k = bch2_btree_iter_peek_slot(&alloc_iter);
 437         ret = bkey_err(k);
 438         if (ret)
 439                 goto out;
 440
 441         if (k.k->type != KEY_TYPE_alloc_v4)
 442                 goto done;
 443
 444         a = bkey_s_c_to_alloc_v4(k);
 445         if (gen >= 0 && a.v->gen != gen)
 446                 goto done;
 447
 448         for (i = 0; i < BCH_ALLOC_V4_NR_BACKPOINTERS(a.v); i++) {
 449                 if (alloc_v4_backpointers_c(a.v)[i].bucket_offset < *bp_offset)
 450                         continue;
 451
 452                 *dst = alloc_v4_backpointers_c(a.v)[i];
 453                 *bp_offset = dst->bucket_offset;
 454                 goto out;
 455         }
 456
 457         for_each_btree_key_norestart(trans, bp_iter, BTREE_ID_backpointers,
 458                                      bp_pos, 0, k, ret) {
 459                 if (bpos_cmp(k.k->p, bp_end_pos) >= 0)
 460                         break;
 461
 462                 if (k.k->type != KEY_TYPE_backpointer)
 463                         continue;
 464
 465                 *dst = *bkey_s_c_to_backpointer(k).v;
 466                 *bp_offset = dst->bucket_offset + BACKPOINTER_OFFSET_MAX;
 467                 goto out;
 468         }
 469 done:
 470         *bp_offset = U64_MAX;
 471 out:
 472         bch2_trans_iter_exit(trans, &bp_iter);
 473         bch2_trans_iter_exit(trans, &alloc_iter);
 474         return ret;
 475 }
 476
 477 static void backpointer_not_found(struct btree_trans *trans,
 478                                   struct bpos bucket,
 479                                   u64 bp_offset,
 480                                   struct bch_backpointer bp,
 481                                   struct bkey_s_c k,
 482                                   const char *thing_it_points_to)
 483 {
 484         struct bch_fs *c = trans->c;
 485         struct printbuf buf = PRINTBUF;
 486
 487         prt_printf(&buf, "backpointer doesn't match %s it points to:\n  ",
 488                    thing_it_points_to);
 489         prt_printf(&buf, "bucket: ");
 490         bch2_bpos_to_text(&buf, bucket);
 491         prt_printf(&buf, "\n  ");
 492
 493         if (bp_offset >= BACKPOINTER_OFFSET_MAX) {
 494                 struct bpos bp_pos =
 495                         bucket_pos_to_bp(c, bucket,
 496                                         bp_offset - BACKPOINTER_OFFSET_MAX);
 497                 prt_printf(&buf, "backpointer pos: ");
 498                 bch2_bpos_to_text(&buf, bp_pos);
 499                 prt_printf(&buf, "\n  ");
 500         }
 501
 502         bch2_backpointer_to_text(&buf, &bp);
 503         prt_printf(&buf, "\n  ");
 504         bch2_bkey_val_to_text(&buf, c, k);
 505         if (!test_bit(BCH_FS_CHECK_BACKPOINTERS_DONE, &c->flags))
 506                 bch_err_ratelimited(c, "%s", buf.buf);
 507         else
 508                 bch2_trans_inconsistent(trans, "%s", buf.buf);
 509
 510         printbuf_exit(&buf);
 511 }
 512
 513 struct bkey_s_c bch2_backpointer_get_key(struct btree_trans *trans,
 514                                          struct btree_iter *iter,
 515                                          struct bpos bucket,
 516                                          u64 bp_offset,
 517                                          struct bch_backpointer bp)
 518 {
 519         struct bch_fs *c = trans->c;
 520         struct bkey_s_c k;
 521
 522         bch2_trans_node_iter_init(trans, iter,
 523                                   bp.btree_id,
 524                                   bp.pos,
 525                                   0,
 526                                   min(bp.level, c->btree_roots[bp.btree_id].level),
 527                                   0);
 528         k = bch2_btree_iter_peek_slot(iter);
 529         if (bkey_err(k)) {
 530                 bch2_trans_iter_exit(trans, iter);
 531                 return k;
 532         }
 533
 534         if (bp.level == c->btree_roots[bp.btree_id].level + 1)
 535                 k = bkey_i_to_s_c(&c->btree_roots[bp.btree_id].key);
 536
 537         if (extent_matches_bp(c, bp.btree_id, bp.level, k, bucket, bp))
 538                 return k;
 539
 540         bch2_trans_iter_exit(trans, iter);
 541
 542         if (bp.level) {
 543                 struct btree *b;
 544
 545                 /*
 546                  * If a backpointer for a btree node wasn't found, it may be
 547                  * because it was overwritten by a new btree node that hasn't
 548                  * been written out yet - backpointer_get_node() checks for
 549                  * this:
 550                  */
 551                 b = bch2_backpointer_get_node(trans, iter, bucket, bp_offset, bp);
 552                 if (!IS_ERR_OR_NULL(b))
 553                         return bkey_i_to_s_c(&b->key);
 554
 555                 bch2_trans_iter_exit(trans, iter);
 556
 557                 if (IS_ERR(b))
 558                         return bkey_s_c_err(PTR_ERR(b));
 559                 return bkey_s_c_null;
 560         }
 561
 562         backpointer_not_found(trans, bucket, bp_offset, bp, k, "extent");
 563         return bkey_s_c_null;
 564 }
 565
 566 struct btree *bch2_backpointer_get_node(struct btree_trans *trans,
 567                                         struct btree_iter *iter,
 568                                         struct bpos bucket,
 569                                         u64 bp_offset,
 570                                         struct bch_backpointer bp)
 571 {
 572         struct bch_fs *c = trans->c;
 573         struct btree *b;
 574
 575         BUG_ON(!bp.level);
 576
 577         bch2_trans_node_iter_init(trans, iter,
 578                                   bp.btree_id,
 579                                   bp.pos,
 580                                   0,
 581                                   bp.level - 1,
 582                                   0);
 583         b = bch2_btree_iter_peek_node(iter);
 584         if (IS_ERR(b))
 585                 goto err;
 586
 587         if (extent_matches_bp(c, bp.btree_id, bp.level,
 588                               bkey_i_to_s_c(&b->key),
 589                               bucket, bp))
 590                 return b;
 591
 592         if (btree_node_will_make_reachable(b)) {
 593                 b = ERR_PTR(-BCH_ERR_backpointer_to_overwritten_btree_node);
 594         } else {
 595                 backpointer_not_found(trans, bucket, bp_offset, bp,
 596                                       bkey_i_to_s_c(&b->key), "btree node");
 597                 b = NULL;
 598         }
 599 err:
 600         bch2_trans_iter_exit(trans, iter);
 601         return b;
 602 }
 603
 604 static int bch2_check_btree_backpointer(struct btree_trans *trans, struct btree_iter *bp_iter,
 605                                         struct bkey_s_c k)
 606 {
 607         struct bch_fs *c = trans->c;
 608         struct btree_iter alloc_iter = { NULL };
 609         struct bch_dev *ca;
 610         struct bkey_s_c alloc_k;
 611         struct printbuf buf = PRINTBUF;
 612         int ret = 0;
 613
 614         if (fsck_err_on(!bch2_dev_exists2(c, k.k->p.inode), c,
 615                         "backpointer for mising device:\n%s",
 616                         (bch2_bkey_val_to_text(&buf, c, k), buf.buf))) {
 617                 ret = bch2_btree_delete_at(trans, bp_iter, 0);
 618                 goto out;
 619         }
 620
 621         ca = bch_dev_bkey_exists(c, k.k->p.inode);
 622
 623         bch2_trans_iter_init(trans, &alloc_iter, BTREE_ID_alloc,
 624                              bp_pos_to_bucket(c, k.k->p), 0);
 625
 626         alloc_k = bch2_btree_iter_peek_slot(&alloc_iter);
 627         ret = bkey_err(alloc_k);
 628         if (ret)
 629                 goto out;
 630
 631         if (fsck_err_on(alloc_k.k->type != KEY_TYPE_alloc_v4, c,
 632                         "backpointer for nonexistent alloc key: %llu:%llu:0\n%s",
 633                         alloc_iter.pos.inode, alloc_iter.pos.offset,
 634                         (bch2_bkey_val_to_text(&buf, c, alloc_k), buf.buf))) {
 635                 ret = bch2_btree_delete_at(trans, bp_iter, 0);
 636                 goto out;
 637         }
 638 out:
 639 fsck_err:
 640         bch2_trans_iter_exit(trans, &alloc_iter);
 641         printbuf_exit(&buf);
 642         return ret;
 643 }
 644
 645 /* verify that every backpointer has a corresponding alloc key */
 646 int bch2_check_btree_backpointers(struct bch_fs *c)
 647 {
 648         struct btree_iter iter;
 649         struct bkey_s_c k;
 650
 651         return bch2_trans_run(c,
 652                 for_each_btree_key_commit(&trans, iter,
 653                         BTREE_ID_backpointers, POS_MIN, 0, k,
 654                         NULL, NULL, BTREE_INSERT_LAZY_RW|BTREE_INSERT_NOFAIL,
 655                   bch2_check_btree_backpointer(&trans, &iter, k)));
 656 }
 657
 658 static int check_bp_exists(struct btree_trans *trans,
 659                            struct bpos bucket_pos,
 660                            struct bch_backpointer bp,
 661                            struct bkey_s_c orig_k)
 662 {
 663         struct bch_fs *c = trans->c;
 664         struct btree_iter alloc_iter, bp_iter = { NULL };
 665         struct printbuf buf = PRINTBUF;
 666         struct bkey_s_c alloc_k, bp_k;
 667         int ret;
 668
 669         bch2_trans_iter_init(trans, &alloc_iter, BTREE_ID_alloc, bucket_pos, 0);
 670         alloc_k = bch2_btree_iter_peek_slot(&alloc_iter);
 671         ret = bkey_err(alloc_k);
 672         if (ret)
 673                 goto err;
 674
 675         if (alloc_k.k->type == KEY_TYPE_alloc_v4) {
 676                 struct bkey_s_c_alloc_v4 a = bkey_s_c_to_alloc_v4(alloc_k);
 677                 const struct bch_backpointer *bps = alloc_v4_backpointers_c(a.v);
 678                 unsigned i, nr = BCH_ALLOC_V4_NR_BACKPOINTERS(a.v);
 679
 680                 for (i = 0; i < nr; i++) {
 681                         int cmp = backpointer_cmp(bps[i], bp) ?:
 682                                 memcmp(&bps[i], &bp, sizeof(bp));
 683                         if (!cmp)
 684                                 goto out;
 685                         if (cmp >= 0)
 686                                 break;
 687                 }
 688         } else {
 689                 goto missing;
 690         }
 691
 692         bch2_trans_iter_init(trans, &bp_iter, BTREE_ID_backpointers,
 693                              bucket_pos_to_bp(c, bucket_pos, bp.bucket_offset),
 694                              0);
 695         bp_k = bch2_btree_iter_peek_slot(&bp_iter);
 696         ret = bkey_err(bp_k);
 697         if (ret)
 698                 goto err;
 699
 700         if (bp_k.k->type != KEY_TYPE_backpointer ||
 701             memcmp(bkey_s_c_to_backpointer(bp_k).v, &bp, sizeof(bp)))
 702                 goto missing;
 703 out:
 704 err:
 705 fsck_err:
 706         bch2_trans_iter_exit(trans, &bp_iter);
 707         bch2_trans_iter_exit(trans, &alloc_iter);
 708         printbuf_exit(&buf);
 709         return ret;
 710 missing:
 711         prt_printf(&buf, "missing backpointer for btree=%s l=%u ",
 712                bch2_btree_ids[bp.btree_id], bp.level);
 713         bch2_bkey_val_to_text(&buf, c, orig_k);
 714         prt_printf(&buf, "\nin alloc key ");
 715         bch2_bkey_val_to_text(&buf, c, alloc_k);
 716
 717         if (c->sb.version < bcachefs_metadata_version_backpointers ||
 718             c->opts.reconstruct_alloc ||
 719             fsck_err(c, "%s", buf.buf)) {
 720                 struct bkey_i_alloc_v4 *a = bch2_alloc_to_v4_mut(trans, alloc_k);
 721
 722                 ret   = PTR_ERR_OR_ZERO(a) ?:
 723                         bch2_bucket_backpointer_add(trans, a, bp, orig_k) ?:
 724                         bch2_trans_update(trans, &alloc_iter, &a->k_i, 0);
 725         }
 726
 727         goto out;
 728 }
 729
 730 static int check_extent_to_backpointers(struct btree_trans *trans,
 731                                         struct btree_iter *iter)
 732 {
 733         struct bch_fs *c = trans->c;
 734         struct bkey_ptrs_c ptrs;
 735         const union bch_extent_entry *entry;
 736         struct extent_ptr_decoded p;
 737         struct bkey_s_c k;
 738         int ret;
 739
 740         k = bch2_btree_iter_peek_all_levels(iter);
 741         ret = bkey_err(k);
 742         if (ret)
 743                 return ret;
 744         if (!k.k)
 745                 return 0;
 746
 747         ptrs = bch2_bkey_ptrs_c(k);
 748         bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
 749                 struct bpos bucket_pos;
 750                 struct bch_backpointer bp;
 751
 752                 if (p.ptr.cached)
 753                         continue;
 754
 755                 bch2_extent_ptr_to_bp(c, iter->btree_id, iter->path->level,
 756                                       k, p, &bucket_pos, &bp);
 757
 758                 ret = check_bp_exists(trans, bucket_pos, bp, k);
 759                 if (ret)
 760                         return ret;
 761         }
 762
 763         return 0;
 764 }
 765
 766 static int check_btree_root_to_backpointers(struct btree_trans *trans,
 767                                             enum btree_id btree_id)
 768 {
 769         struct bch_fs *c = trans->c;
 770         struct btree_iter iter;
 771         struct btree *b;
 772         struct bkey_s_c k;
 773         struct bkey_ptrs_c ptrs;
 774         struct extent_ptr_decoded p;
 775         const union bch_extent_entry *entry;
 776         int ret;
 777
 778         bch2_trans_node_iter_init(trans, &iter, btree_id, POS_MIN, 0,
 779                                   c->btree_roots[btree_id].level, 0);
 780         b = bch2_btree_iter_peek_node(&iter);
 781         ret = PTR_ERR_OR_ZERO(b);
 782         if (ret)
 783                 goto err;
 784
 785         BUG_ON(b != btree_node_root(c, b));
 786
 787         k = bkey_i_to_s_c(&b->key);
 788         ptrs = bch2_bkey_ptrs_c(k);
 789         bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
 790                 struct bpos bucket_pos;
 791                 struct bch_backpointer bp;
 792
 793                 if (p.ptr.cached)
 794                         continue;
 795
 796                 bch2_extent_ptr_to_bp(c, iter.btree_id, iter.path->level + 1,
 797                                       k, p, &bucket_pos, &bp);
 798
 799                 ret = check_bp_exists(trans, bucket_pos, bp, k);
 800                 if (ret)
 801                         goto err;
 802         }
 803 err:
 804         bch2_trans_iter_exit(trans, &iter);
 805         return ret;
 806 }
 807
 808 static inline struct bbpos bp_to_bbpos(struct bch_backpointer bp)
 809 {
 810         return (struct bbpos) {
 811                 .btree  = bp.btree_id,
 812                 .pos    = bp.pos,
 813         };
 814 }
 815
 816 static size_t btree_nodes_fit_in_ram(struct bch_fs *c)
 817 {
 818         struct sysinfo i;
 819
 820         si_meminfo(&i);
 821         return (i.totalram >> 1) / btree_bytes(c);
 822 }
 823
 824 int bch2_get_btree_in_memory_pos(struct btree_trans *trans,
 825                                  unsigned btree_leaf_mask,
 826                                  unsigned btree_interior_mask,
 827                                  struct bbpos start, struct bbpos *end)
 828 {
 829         struct btree_iter iter;
 830         struct bkey_s_c k;
 831         size_t btree_nodes = btree_nodes_fit_in_ram(trans->c);
 832         enum btree_id btree;
 833         int ret = 0;
 834
 835         for (btree = start.btree; btree < BTREE_ID_NR && !ret; btree++) {
 836                 unsigned depth = ((1U << btree) & btree_leaf_mask) ? 1 : 2;
 837
 838                 if (!((1U << btree) & btree_leaf_mask) &&
 839                     !((1U << btree) & btree_interior_mask))
 840                         continue;
 841
 842                 bch2_trans_node_iter_init(trans, &iter, btree,
 843                                           btree == start.btree ? start.pos : POS_MIN,
 844                                           0, depth, 0);
 845                 /*
 846                  * for_each_btree_key_contineu() doesn't check the return value
 847                  * from bch2_btree_iter_advance(), which is needed when
 848                  * iterating over interior nodes where we'll see keys at
 849                  * SPOS_MAX:
 850                  */
 851                 do {
 852                         k = __bch2_btree_iter_peek_and_restart(trans, &iter, 0);
 853                         ret = bkey_err(k);
 854                         if (!k.k || ret)
 855                                 break;
 856
 857                         --btree_nodes;
 858                         if (!btree_nodes) {
 859                                 *end = BBPOS(btree, k.k->p);
 860                                 bch2_trans_iter_exit(trans, &iter);
 861                                 return 0;
 862                         }
 863                 } while (bch2_btree_iter_advance(&iter));
 864                 bch2_trans_iter_exit(trans, &iter);
 865         }
 866
 867         *end = BBPOS_MAX;
 868         return ret;
 869 }
 870
 871 int bch2_check_extents_to_backpointers(struct bch_fs *c)
 872 {
 873         struct btree_trans trans;
 874         struct btree_iter iter;
 875         enum btree_id btree_id;
 876         int ret = 0;
 877
 878         bch2_trans_init(&trans, c, 0, 0);
 879         for (btree_id = 0; btree_id < BTREE_ID_NR; btree_id++) {
 880                 unsigned depth = btree_type_has_ptrs(btree_id) ? 0 : 1;
 881
 882                 bch2_trans_node_iter_init(&trans, &iter, btree_id, POS_MIN, 0,
 883                                           depth,
 884                                           BTREE_ITER_ALL_LEVELS|
 885                                           BTREE_ITER_PREFETCH);
 886
 887                 do {
 888                         ret = commit_do(&trans, NULL, NULL,
 889                                               BTREE_INSERT_LAZY_RW|
 890                                               BTREE_INSERT_NOFAIL,
 891                                               check_extent_to_backpointers(&trans, &iter));
 892                         if (ret)
 893                                 break;
 894                 } while (!bch2_btree_iter_advance(&iter));
 895
 896                 bch2_trans_iter_exit(&trans, &iter);
 897
 898                 if (ret)
 899                         break;
 900
 901                 ret = commit_do(&trans, NULL, NULL,
 902                                       BTREE_INSERT_LAZY_RW|
 903                                       BTREE_INSERT_NOFAIL,
 904                                       check_btree_root_to_backpointers(&trans, btree_id));
 905                 if (ret)
 906                         break;
 907         }
 908         bch2_trans_exit(&trans);
 909         return ret;
 910 }
 911
 912 static int check_one_backpointer(struct btree_trans *trans,
 913                                  struct bpos bucket,
 914                                  u64 *bp_offset,
 915                                  struct bbpos start,
 916                                  struct bbpos end)
 917 {
 918         struct btree_iter iter;
 919         struct bch_backpointer bp;
 920         struct bbpos pos;
 921         struct bkey_s_c k;
 922         struct printbuf buf = PRINTBUF;
 923         int ret;
 924
 925         ret = bch2_get_next_backpointer(trans, bucket, -1, bp_offset, &bp);
 926         if (ret || *bp_offset == U64_MAX)
 927                 return ret;
 928
 929         pos = bp_to_bbpos(bp);
 930         if (bbpos_cmp(pos, start) < 0 ||
 931             bbpos_cmp(pos, end) > 0)
 932                 return 0;
 933
 934         k = bch2_backpointer_get_key(trans, &iter, bucket, *bp_offset, bp);
 935         ret = bkey_err(k);
 936         if (ret == -BCH_ERR_backpointer_to_overwritten_btree_node)
 937                 return 0;
 938         if (ret)
 939                 return ret;
 940
 941         if (fsck_err_on(!k.k, trans->c,
 942                         "%s backpointer points to missing extent\n%s",
 943                         *bp_offset < BACKPOINTER_OFFSET_MAX ? "alloc" : "btree",
 944                         (bch2_backpointer_to_text(&buf, &bp), buf.buf))) {
 945                 ret = bch2_backpointer_del_by_offset(trans, bucket, *bp_offset, bp);
 946                 if (ret == -ENOENT)
 947                         bch_err(trans->c, "backpointer at %llu not found", *bp_offset);
 948         }
 949
 950         bch2_trans_iter_exit(trans, &iter);
 951 fsck_err:
 952         printbuf_exit(&buf);
 953         return ret;
 954 }
 955
 956 static int bch2_check_backpointers_to_extents_pass(struct btree_trans *trans,
 957                                                    struct bbpos start,
 958                                                    struct bbpos end)
 959 {
 960         struct btree_iter iter;
 961         struct bkey_s_c k;
 962         int ret = 0;
 963
 964         for_each_btree_key(trans, iter, BTREE_ID_alloc, POS_MIN,
 965                            BTREE_ITER_PREFETCH, k, ret) {
 966                 u64 bp_offset = 0;
 967
 968                 while (!(ret = commit_do(trans, NULL, NULL,
 969                                          BTREE_INSERT_LAZY_RW|
 970                                          BTREE_INSERT_NOFAIL,
 971                                 check_one_backpointer(trans, iter.pos, &bp_offset, start, end))) &&
 972                        bp_offset < U64_MAX)
 973                         bp_offset++;
 974
 975                 if (ret)
 976                         break;
 977         }
 978         bch2_trans_iter_exit(trans, &iter);
 979         return ret < 0 ? ret : 0;
 980 }
 981
 982 int bch2_check_backpointers_to_extents(struct bch_fs *c)
 983 {
 984         struct btree_trans trans;
 985         struct bbpos start = (struct bbpos) { .btree = 0, .pos = POS_MIN, }, end;
 986         int ret;
 987
 988         bch2_trans_init(&trans, c, 0, 0);
 989         while (1) {
 990                 ret = bch2_get_btree_in_memory_pos(&trans,
 991                                                    (1U << BTREE_ID_extents)|
 992                                                    (1U << BTREE_ID_reflink),
 993                                                    ~0,
 994                                                    start, &end);
 995                 if (ret)
 996                         break;
 997
 998                 if (!bbpos_cmp(start, BBPOS_MIN) &&
 999                     bbpos_cmp(end, BBPOS_MAX))
1000                         bch_verbose(c, "check_backpointers_to_extents(): extents do not fit in ram,"
1001                                     "running in multiple passes with %zu nodes per pass",
1002                                     btree_nodes_fit_in_ram(c));
1003
1004                 if (bbpos_cmp(start, BBPOS_MIN) ||
1005                     bbpos_cmp(end, BBPOS_MAX)) {
1006                         struct printbuf buf = PRINTBUF;
1007
1008                         prt_str(&buf, "check_backointers_to_extents(): ");
1009                         bch2_bbpos_to_text(&buf, start);
1010                         prt_str(&buf, "-");
1011                         bch2_bbpos_to_text(&buf, end);
1012
1013                         bch_verbose(c, "%s", buf.buf);
1014                         printbuf_exit(&buf);
1015                 }
1016
1017                 ret = bch2_check_backpointers_to_extents_pass(&trans, start, end);
1018                 if (ret || !bbpos_cmp(end, BBPOS_MAX))
1019                         break;
1020
1021                 start = bbpos_successor(end);
1022         }
1023         bch2_trans_exit(&trans);
1024
1025         return ret;
1026 }