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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2010 Kent Overstreet <kent.overstreet@gmail.com>
   4  * Copyright (C) 2014 Datera Inc.
   5  */
   6
   7 #include "bcachefs.h"
   8 #include "alloc_background.h"
   9 #include "alloc_foreground.h"
  10 #include "bkey_methods.h"
  11 #include "bkey_buf.h"
  12 #include "btree_journal_iter.h"
  13 #include "btree_key_cache.h"
  14 #include "btree_locking.h"
  15 #include "btree_update_interior.h"
  16 #include "btree_io.h"
  17 #include "btree_gc.h"
  18 #include "buckets.h"
  19 #include "clock.h"
  20 #include "debug.h"
  21 #include "ec.h"
  22 #include "error.h"
  23 #include "extents.h"
  24 #include "journal.h"
  25 #include "keylist.h"
  26 #include "move.h"
  27 #include "recovery.h"
  28 #include "reflink.h"
  29 #include "replicas.h"
  30 #include "super-io.h"
  31 #include "trace.h"
  32
  33 #include <linux/slab.h>
  34 #include <linux/bitops.h>
  35 #include <linux/freezer.h>
  36 #include <linux/kthread.h>
  37 #include <linux/preempt.h>
  38 #include <linux/rcupdate.h>
  39 #include <linux/sched/task.h>
  40
  41 #define DROP_THIS_NODE          10
  42 #define DROP_PREV_NODE          11
  43
  44 static bool should_restart_for_topology_repair(struct bch_fs *c)
  45 {
  46         return c->opts.fix_errors != FSCK_FIX_no &&
  47                 !(c->recovery_passes_complete & BIT_ULL(BCH_RECOVERY_PASS_check_topology));
  48 }
  49
  50 static inline void __gc_pos_set(struct bch_fs *c, struct gc_pos new_pos)
  51 {
  52         preempt_disable();
  53         write_seqcount_begin(&c->gc_pos_lock);
  54         c->gc_pos = new_pos;
  55         write_seqcount_end(&c->gc_pos_lock);
  56         preempt_enable();
  57 }
  58
  59 static inline void gc_pos_set(struct bch_fs *c, struct gc_pos new_pos)
  60 {
  61         BUG_ON(gc_pos_cmp(new_pos, c->gc_pos) <= 0);
  62         __gc_pos_set(c, new_pos);
  63 }
  64
  65 /*
  66  * Missing: if an interior btree node is empty, we need to do something -
  67  * perhaps just kill it
  68  */
  69 static int bch2_gc_check_topology(struct bch_fs *c,
  70                                   struct btree *b,
  71                                   struct bkey_buf *prev,
  72                                   struct bkey_buf cur,
  73                                   bool is_last)
  74 {
  75         struct bpos node_start  = b->data->min_key;
  76         struct bpos node_end    = b->data->max_key;
  77         struct bpos expected_start = bkey_deleted(&prev->k->k)
  78                 ? node_start
  79                 : bpos_successor(prev->k->k.p);
  80         struct printbuf buf1 = PRINTBUF, buf2 = PRINTBUF;
  81         int ret = 0;
  82
  83         if (cur.k->k.type == KEY_TYPE_btree_ptr_v2) {
  84                 struct bkey_i_btree_ptr_v2 *bp = bkey_i_to_btree_ptr_v2(cur.k);
  85
  86                 if (!bpos_eq(expected_start, bp->v.min_key)) {
  87                         bch2_topology_error(c);
  88
  89                         if (bkey_deleted(&prev->k->k)) {
  90                                 prt_printf(&buf1, "start of node: ");
  91                                 bch2_bpos_to_text(&buf1, node_start);
  92                         } else {
  93                                 bch2_bkey_val_to_text(&buf1, c, bkey_i_to_s_c(prev->k));
  94                         }
  95                         bch2_bkey_val_to_text(&buf2, c, bkey_i_to_s_c(cur.k));
  96
  97                         if (__fsck_err(c,
  98                                        FSCK_CAN_FIX|
  99                                        FSCK_CAN_IGNORE|
 100                                        FSCK_NO_RATELIMIT,
 101                                        btree_node_topology_bad_min_key,
 102                                        "btree node with incorrect min_key at btree %s level %u:\n"
 103                                        "  prev %s\n"
 104                                        "  cur %s",
 105                                        bch2_btree_id_str(b->c.btree_id), b->c.level,
 106                                        buf1.buf, buf2.buf) && should_restart_for_topology_repair(c)) {
 107                                 bch_info(c, "Halting mark and sweep to start topology repair pass");
 108                                 ret = bch2_run_explicit_recovery_pass(c, BCH_RECOVERY_PASS_check_topology);
 109                                 goto err;
 110                         } else {
 111                                 set_bit(BCH_FS_initial_gc_unfixed, &c->flags);
 112                         }
 113                 }
 114         }
 115
 116         if (is_last && !bpos_eq(cur.k->k.p, node_end)) {
 117                 bch2_topology_error(c);
 118
 119                 printbuf_reset(&buf1);
 120                 printbuf_reset(&buf2);
 121
 122                 bch2_bkey_val_to_text(&buf1, c, bkey_i_to_s_c(cur.k));
 123                 bch2_bpos_to_text(&buf2, node_end);
 124
 125                 if (__fsck_err(c, FSCK_CAN_FIX|FSCK_CAN_IGNORE|FSCK_NO_RATELIMIT,
 126                           btree_node_topology_bad_max_key,
 127                           "btree node with incorrect max_key at btree %s level %u:\n"
 128                           "  %s\n"
 129                           "  expected %s",
 130                           bch2_btree_id_str(b->c.btree_id), b->c.level,
 131                           buf1.buf, buf2.buf) &&
 132                     should_restart_for_topology_repair(c)) {
 133                         bch_info(c, "Halting mark and sweep to start topology repair pass");
 134                         ret = bch2_run_explicit_recovery_pass(c, BCH_RECOVERY_PASS_check_topology);
 135                         goto err;
 136                 } else {
 137                         set_bit(BCH_FS_initial_gc_unfixed, &c->flags);
 138                 }
 139         }
 140
 141         bch2_bkey_buf_copy(prev, c, cur.k);
 142 err:
 143 fsck_err:
 144         printbuf_exit(&buf2);
 145         printbuf_exit(&buf1);
 146         return ret;
 147 }
 148
 149 static void btree_ptr_to_v2(struct btree *b, struct bkey_i_btree_ptr_v2 *dst)
 150 {
 151         switch (b->key.k.type) {
 152         case KEY_TYPE_btree_ptr: {
 153                 struct bkey_i_btree_ptr *src = bkey_i_to_btree_ptr(&b->key);
 154
 155                 dst->k.p                = src->k.p;
 156                 dst->v.mem_ptr          = 0;
 157                 dst->v.seq              = b->data->keys.seq;
 158                 dst->v.sectors_written  = 0;
 159                 dst->v.flags            = 0;
 160                 dst->v.min_key          = b->data->min_key;
 161                 set_bkey_val_bytes(&dst->k, sizeof(dst->v) + bkey_val_bytes(&src->k));
 162                 memcpy(dst->v.start, src->v.start, bkey_val_bytes(&src->k));
 163                 break;
 164         }
 165         case KEY_TYPE_btree_ptr_v2:
 166                 bkey_copy(&dst->k_i, &b->key);
 167                 break;
 168         default:
 169                 BUG();
 170         }
 171 }
 172
 173 static void bch2_btree_node_update_key_early(struct btree_trans *trans,
 174                                              enum btree_id btree, unsigned level,
 175                                              struct bkey_s_c old, struct bkey_i *new)
 176 {
 177         struct bch_fs *c = trans->c;
 178         struct btree *b;
 179         struct bkey_buf tmp;
 180         int ret;
 181
 182         bch2_bkey_buf_init(&tmp);
 183         bch2_bkey_buf_reassemble(&tmp, c, old);
 184
 185         b = bch2_btree_node_get_noiter(trans, tmp.k, btree, level, true);
 186         if (!IS_ERR_OR_NULL(b)) {
 187                 mutex_lock(&c->btree_cache.lock);
 188
 189                 bch2_btree_node_hash_remove(&c->btree_cache, b);
 190
 191                 bkey_copy(&b->key, new);
 192                 ret = __bch2_btree_node_hash_insert(&c->btree_cache, b);
 193                 BUG_ON(ret);
 194
 195                 mutex_unlock(&c->btree_cache.lock);
 196                 six_unlock_read(&b->c.lock);
 197         }
 198
 199         bch2_bkey_buf_exit(&tmp, c);
 200 }
 201
 202 static int set_node_min(struct bch_fs *c, struct btree *b, struct bpos new_min)
 203 {
 204         struct bkey_i_btree_ptr_v2 *new;
 205         int ret;
 206
 207         new = kmalloc_array(BKEY_BTREE_PTR_U64s_MAX, sizeof(u64), GFP_KERNEL);
 208         if (!new)
 209                 return -BCH_ERR_ENOMEM_gc_repair_key;
 210
 211         btree_ptr_to_v2(b, new);
 212         b->data->min_key        = new_min;
 213         new->v.min_key          = new_min;
 214         SET_BTREE_PTR_RANGE_UPDATED(&new->v, true);
 215
 216         ret = bch2_journal_key_insert_take(c, b->c.btree_id, b->c.level + 1, &new->k_i);
 217         if (ret) {
 218                 kfree(new);
 219                 return ret;
 220         }
 221
 222         bch2_btree_node_drop_keys_outside_node(b);
 223         bkey_copy(&b->key, &new->k_i);
 224         return 0;
 225 }
 226
 227 static int set_node_max(struct bch_fs *c, struct btree *b, struct bpos new_max)
 228 {
 229         struct bkey_i_btree_ptr_v2 *new;
 230         int ret;
 231
 232         ret = bch2_journal_key_delete(c, b->c.btree_id, b->c.level + 1, b->key.k.p);
 233         if (ret)
 234                 return ret;
 235
 236         new = kmalloc_array(BKEY_BTREE_PTR_U64s_MAX, sizeof(u64), GFP_KERNEL);
 237         if (!new)
 238                 return -BCH_ERR_ENOMEM_gc_repair_key;
 239
 240         btree_ptr_to_v2(b, new);
 241         b->data->max_key        = new_max;
 242         new->k.p                = new_max;
 243         SET_BTREE_PTR_RANGE_UPDATED(&new->v, true);
 244
 245         ret = bch2_journal_key_insert_take(c, b->c.btree_id, b->c.level + 1, &new->k_i);
 246         if (ret) {
 247                 kfree(new);
 248                 return ret;
 249         }
 250
 251         bch2_btree_node_drop_keys_outside_node(b);
 252
 253         mutex_lock(&c->btree_cache.lock);
 254         bch2_btree_node_hash_remove(&c->btree_cache, b);
 255
 256         bkey_copy(&b->key, &new->k_i);
 257         ret = __bch2_btree_node_hash_insert(&c->btree_cache, b);
 258         BUG_ON(ret);
 259         mutex_unlock(&c->btree_cache.lock);
 260         return 0;
 261 }
 262
 263 static int btree_repair_node_boundaries(struct bch_fs *c, struct btree *b,
 264                                         struct btree *prev, struct btree *cur)
 265 {
 266         struct bpos expected_start = !prev
 267                 ? b->data->min_key
 268                 : bpos_successor(prev->key.k.p);
 269         struct printbuf buf1 = PRINTBUF, buf2 = PRINTBUF;
 270         int ret = 0;
 271
 272         if (!prev) {
 273                 prt_printf(&buf1, "start of node: ");
 274                 bch2_bpos_to_text(&buf1, b->data->min_key);
 275         } else {
 276                 bch2_bkey_val_to_text(&buf1, c, bkey_i_to_s_c(&prev->key));
 277         }
 278
 279         bch2_bkey_val_to_text(&buf2, c, bkey_i_to_s_c(&cur->key));
 280
 281         if (prev &&
 282             bpos_gt(expected_start, cur->data->min_key) &&
 283             BTREE_NODE_SEQ(cur->data) > BTREE_NODE_SEQ(prev->data)) {
 284                 /* cur overwrites prev: */
 285
 286                 if (mustfix_fsck_err_on(bpos_ge(prev->data->min_key,
 287                                                 cur->data->min_key), c,
 288                                 btree_node_topology_overwritten_by_next_node,
 289                                 "btree node overwritten by next node at btree %s level %u:\n"
 290                                 "  node %s\n"
 291                                 "  next %s",
 292                                 bch2_btree_id_str(b->c.btree_id), b->c.level,
 293                                 buf1.buf, buf2.buf)) {
 294                         ret = DROP_PREV_NODE;
 295                         goto out;
 296                 }
 297
 298                 if (mustfix_fsck_err_on(!bpos_eq(prev->key.k.p,
 299                                                  bpos_predecessor(cur->data->min_key)), c,
 300                                 btree_node_topology_bad_max_key,
 301                                 "btree node with incorrect max_key at btree %s level %u:\n"
 302                                 "  node %s\n"
 303                                 "  next %s",
 304                                 bch2_btree_id_str(b->c.btree_id), b->c.level,
 305                                 buf1.buf, buf2.buf))
 306                         ret = set_node_max(c, prev,
 307                                            bpos_predecessor(cur->data->min_key));
 308         } else {
 309                 /* prev overwrites cur: */
 310
 311                 if (mustfix_fsck_err_on(bpos_ge(expected_start,
 312                                                 cur->data->max_key), c,
 313                                 btree_node_topology_overwritten_by_prev_node,
 314                                 "btree node overwritten by prev node at btree %s level %u:\n"
 315                                 "  prev %s\n"
 316                                 "  node %s",
 317                                 bch2_btree_id_str(b->c.btree_id), b->c.level,
 318                                 buf1.buf, buf2.buf)) {
 319                         ret = DROP_THIS_NODE;
 320                         goto out;
 321                 }
 322
 323                 if (mustfix_fsck_err_on(!bpos_eq(expected_start, cur->data->min_key), c,
 324                                 btree_node_topology_bad_min_key,
 325                                 "btree node with incorrect min_key at btree %s level %u:\n"
 326                                 "  prev %s\n"
 327                                 "  node %s",
 328                                 bch2_btree_id_str(b->c.btree_id), b->c.level,
 329                                 buf1.buf, buf2.buf))
 330                         ret = set_node_min(c, cur, expected_start);
 331         }
 332 out:
 333 fsck_err:
 334         printbuf_exit(&buf2);
 335         printbuf_exit(&buf1);
 336         return ret;
 337 }
 338
 339 static int btree_repair_node_end(struct bch_fs *c, struct btree *b,
 340                                  struct btree *child)
 341 {
 342         struct printbuf buf1 = PRINTBUF, buf2 = PRINTBUF;
 343         int ret = 0;
 344
 345         bch2_bkey_val_to_text(&buf1, c, bkey_i_to_s_c(&child->key));
 346         bch2_bpos_to_text(&buf2, b->key.k.p);
 347
 348         if (mustfix_fsck_err_on(!bpos_eq(child->key.k.p, b->key.k.p), c,
 349                                 btree_node_topology_bad_max_key,
 350                         "btree node with incorrect max_key at btree %s level %u:\n"
 351                         "  %s\n"
 352                         "  expected %s",
 353                         bch2_btree_id_str(b->c.btree_id), b->c.level,
 354                         buf1.buf, buf2.buf)) {
 355                 ret = set_node_max(c, child, b->key.k.p);
 356                 if (ret)
 357                         goto err;
 358         }
 359 err:
 360 fsck_err:
 361         printbuf_exit(&buf2);
 362         printbuf_exit(&buf1);
 363         return ret;
 364 }
 365
 366 static int bch2_btree_repair_topology_recurse(struct btree_trans *trans, struct btree *b)
 367 {
 368         struct bch_fs *c = trans->c;
 369         struct btree_and_journal_iter iter;
 370         struct bkey_s_c k;
 371         struct bkey_buf prev_k, cur_k;
 372         struct btree *prev = NULL, *cur = NULL;
 373         bool have_child, dropped_children = false;
 374         struct printbuf buf = PRINTBUF;
 375         int ret = 0;
 376
 377         if (!b->c.level)
 378                 return 0;
 379 again:
 380         prev = NULL;
 381         have_child = dropped_children = false;
 382         bch2_bkey_buf_init(&prev_k);
 383         bch2_bkey_buf_init(&cur_k);
 384         bch2_btree_and_journal_iter_init_node_iter(&iter, c, b);
 385
 386         while ((k = bch2_btree_and_journal_iter_peek(&iter)).k) {
 387                 BUG_ON(bpos_lt(k.k->p, b->data->min_key));
 388                 BUG_ON(bpos_gt(k.k->p, b->data->max_key));
 389
 390                 bch2_btree_and_journal_iter_advance(&iter);
 391                 bch2_bkey_buf_reassemble(&cur_k, c, k);
 392
 393                 cur = bch2_btree_node_get_noiter(trans, cur_k.k,
 394                                         b->c.btree_id, b->c.level - 1,
 395                                         false);
 396                 ret = PTR_ERR_OR_ZERO(cur);
 397
 398                 printbuf_reset(&buf);
 399                 bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(cur_k.k));
 400
 401                 if (mustfix_fsck_err_on(ret == -EIO, c,
 402                                 btree_node_unreadable,
 403                                 "Topology repair: unreadable btree node at btree %s level %u:\n"
 404                                 "  %s",
 405                                 bch2_btree_id_str(b->c.btree_id),
 406                                 b->c.level - 1,
 407                                 buf.buf)) {
 408                         bch2_btree_node_evict(trans, cur_k.k);
 409                         ret = bch2_journal_key_delete(c, b->c.btree_id,
 410                                                       b->c.level, cur_k.k->k.p);
 411                         cur = NULL;
 412                         if (ret)
 413                                 break;
 414                         continue;
 415                 }
 416
 417                 bch_err_msg(c, ret, "getting btree node");
 418                 if (ret)
 419                         break;
 420
 421                 ret = btree_repair_node_boundaries(c, b, prev, cur);
 422
 423                 if (ret == DROP_THIS_NODE) {
 424                         six_unlock_read(&cur->c.lock);
 425                         bch2_btree_node_evict(trans, cur_k.k);
 426                         ret = bch2_journal_key_delete(c, b->c.btree_id,
 427                                                       b->c.level, cur_k.k->k.p);
 428                         cur = NULL;
 429                         if (ret)
 430                                 break;
 431                         continue;
 432                 }
 433
 434                 if (prev)
 435                         six_unlock_read(&prev->c.lock);
 436                 prev = NULL;
 437
 438                 if (ret == DROP_PREV_NODE) {
 439                         bch2_btree_node_evict(trans, prev_k.k);
 440                         ret = bch2_journal_key_delete(c, b->c.btree_id,
 441                                                       b->c.level, prev_k.k->k.p);
 442                         if (ret)
 443                                 break;
 444
 445                         bch2_btree_and_journal_iter_exit(&iter);
 446                         bch2_bkey_buf_exit(&prev_k, c);
 447                         bch2_bkey_buf_exit(&cur_k, c);
 448                         goto again;
 449                 } else if (ret)
 450                         break;
 451
 452                 prev = cur;
 453                 cur = NULL;
 454                 bch2_bkey_buf_copy(&prev_k, c, cur_k.k);
 455         }
 456
 457         if (!ret && !IS_ERR_OR_NULL(prev)) {
 458                 BUG_ON(cur);
 459                 ret = btree_repair_node_end(c, b, prev);
 460         }
 461
 462         if (!IS_ERR_OR_NULL(prev))
 463                 six_unlock_read(&prev->c.lock);
 464         prev = NULL;
 465         if (!IS_ERR_OR_NULL(cur))
 466                 six_unlock_read(&cur->c.lock);
 467         cur = NULL;
 468
 469         if (ret)
 470                 goto err;
 471
 472         bch2_btree_and_journal_iter_exit(&iter);
 473         bch2_btree_and_journal_iter_init_node_iter(&iter, c, b);
 474
 475         while ((k = bch2_btree_and_journal_iter_peek(&iter)).k) {
 476                 bch2_bkey_buf_reassemble(&cur_k, c, k);
 477                 bch2_btree_and_journal_iter_advance(&iter);
 478
 479                 cur = bch2_btree_node_get_noiter(trans, cur_k.k,
 480                                         b->c.btree_id, b->c.level - 1,
 481                                         false);
 482                 ret = PTR_ERR_OR_ZERO(cur);
 483
 484                 bch_err_msg(c, ret, "getting btree node");
 485                 if (ret)
 486                         goto err;
 487
 488                 ret = bch2_btree_repair_topology_recurse(trans, cur);
 489                 six_unlock_read(&cur->c.lock);
 490                 cur = NULL;
 491
 492                 if (ret == DROP_THIS_NODE) {
 493                         bch2_btree_node_evict(trans, cur_k.k);
 494                         ret = bch2_journal_key_delete(c, b->c.btree_id,
 495                                                       b->c.level, cur_k.k->k.p);
 496                         dropped_children = true;
 497                 }
 498
 499                 if (ret)
 500                         goto err;
 501
 502                 have_child = true;
 503         }
 504
 505         printbuf_reset(&buf);
 506         bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&b->key));
 507
 508         if (mustfix_fsck_err_on(!have_child, c,
 509                         btree_node_topology_interior_node_empty,
 510                         "empty interior btree node at btree %s level %u\n"
 511                         "  %s",
 512                         bch2_btree_id_str(b->c.btree_id),
 513                         b->c.level, buf.buf))
 514                 ret = DROP_THIS_NODE;
 515 err:
 516 fsck_err:
 517         if (!IS_ERR_OR_NULL(prev))
 518                 six_unlock_read(&prev->c.lock);
 519         if (!IS_ERR_OR_NULL(cur))
 520                 six_unlock_read(&cur->c.lock);
 521
 522         bch2_btree_and_journal_iter_exit(&iter);
 523         bch2_bkey_buf_exit(&prev_k, c);
 524         bch2_bkey_buf_exit(&cur_k, c);
 525
 526         if (!ret && dropped_children)
 527                 goto again;
 528
 529         printbuf_exit(&buf);
 530         return ret;
 531 }
 532
 533 int bch2_check_topology(struct bch_fs *c)
 534 {
 535         struct btree_trans *trans = bch2_trans_get(c);
 536         struct btree *b;
 537         unsigned i;
 538         int ret = 0;
 539
 540         for (i = 0; i < btree_id_nr_alive(c) && !ret; i++) {
 541                 struct btree_root *r = bch2_btree_id_root(c, i);
 542
 543                 if (!r->alive)
 544                         continue;
 545
 546                 b = r->b;
 547                 if (btree_node_fake(b))
 548                         continue;
 549
 550                 btree_node_lock_nopath_nofail(trans, &b->c, SIX_LOCK_read);
 551                 ret = bch2_btree_repair_topology_recurse(trans, b);
 552                 six_unlock_read(&b->c.lock);
 553
 554                 if (ret == DROP_THIS_NODE) {
 555                         bch_err(c, "empty btree root - repair unimplemented");
 556                         ret = -BCH_ERR_fsck_repair_unimplemented;
 557                 }
 558         }
 559
 560         bch2_trans_put(trans);
 561
 562         return ret;
 563 }
 564
 565 static int bch2_check_fix_ptrs(struct btree_trans *trans, enum btree_id btree_id,
 566                                unsigned level, bool is_root,
 567                                struct bkey_s_c *k)
 568 {
 569         struct bch_fs *c = trans->c;
 570         struct bkey_ptrs_c ptrs_c = bch2_bkey_ptrs_c(*k);
 571         const union bch_extent_entry *entry_c;
 572         struct extent_ptr_decoded p = { 0 };
 573         bool do_update = false;
 574         struct printbuf buf = PRINTBUF;
 575         int ret = 0;
 576
 577         /*
 578          * XXX
 579          * use check_bucket_ref here
 580          */
 581         bkey_for_each_ptr_decode(k->k, ptrs_c, p, entry_c) {
 582                 struct bch_dev *ca = bch_dev_bkey_exists(c, p.ptr.dev);
 583                 struct bucket *g = PTR_GC_BUCKET(ca, &p.ptr);
 584                 enum bch_data_type data_type = bch2_bkey_ptr_data_type(*k, &entry_c->ptr);
 585
 586                 if (!g->gen_valid &&
 587                     (c->opts.reconstruct_alloc ||
 588                      fsck_err(c, ptr_to_missing_alloc_key,
 589                               "bucket %u:%zu data type %s ptr gen %u missing in alloc btree\n"
 590                               "while marking %s",
 591                               p.ptr.dev, PTR_BUCKET_NR(ca, &p.ptr),
 592                               bch2_data_types[ptr_data_type(k->k, &p.ptr)],
 593                               p.ptr.gen,
 594                               (printbuf_reset(&buf),
 595                                bch2_bkey_val_to_text(&buf, c, *k), buf.buf)))) {
 596                         if (!p.ptr.cached) {
 597                                 g->gen_valid            = true;
 598                                 g->gen                  = p.ptr.gen;
 599                         } else {
 600                                 do_update = true;
 601                         }
 602                 }
 603
 604                 if (gen_cmp(p.ptr.gen, g->gen) > 0 &&
 605                     (c->opts.reconstruct_alloc ||
 606                      fsck_err(c, ptr_gen_newer_than_bucket_gen,
 607                               "bucket %u:%zu data type %s ptr gen in the future: %u > %u\n"
 608                               "while marking %s",
 609                               p.ptr.dev, PTR_BUCKET_NR(ca, &p.ptr),
 610                               bch2_data_types[ptr_data_type(k->k, &p.ptr)],
 611                               p.ptr.gen, g->gen,
 612                               (printbuf_reset(&buf),
 613                                bch2_bkey_val_to_text(&buf, c, *k), buf.buf)))) {
 614                         if (!p.ptr.cached) {
 615                                 g->gen_valid            = true;
 616                                 g->gen                  = p.ptr.gen;
 617                                 g->data_type            = 0;
 618                                 g->dirty_sectors        = 0;
 619                                 g->cached_sectors       = 0;
 620                                 set_bit(BCH_FS_need_another_gc, &c->flags);
 621                         } else {
 622                                 do_update = true;
 623                         }
 624                 }
 625
 626                 if (gen_cmp(g->gen, p.ptr.gen) > BUCKET_GC_GEN_MAX &&
 627                     (c->opts.reconstruct_alloc ||
 628                      fsck_err(c, ptr_gen_newer_than_bucket_gen,
 629                               "bucket %u:%zu gen %u data type %s: ptr gen %u too stale\n"
 630                               "while marking %s",
 631                               p.ptr.dev, PTR_BUCKET_NR(ca, &p.ptr), g->gen,
 632                               bch2_data_types[ptr_data_type(k->k, &p.ptr)],
 633                               p.ptr.gen,
 634                               (printbuf_reset(&buf),
 635                                bch2_bkey_val_to_text(&buf, c, *k), buf.buf))))
 636                         do_update = true;
 637
 638                 if (!p.ptr.cached && gen_cmp(p.ptr.gen, g->gen) < 0 &&
 639                     (c->opts.reconstruct_alloc ||
 640                      fsck_err(c, stale_dirty_ptr,
 641                               "bucket %u:%zu data type %s stale dirty ptr: %u < %u\n"
 642                               "while marking %s",
 643                               p.ptr.dev, PTR_BUCKET_NR(ca, &p.ptr),
 644                               bch2_data_types[ptr_data_type(k->k, &p.ptr)],
 645                               p.ptr.gen, g->gen,
 646                               (printbuf_reset(&buf),
 647                                bch2_bkey_val_to_text(&buf, c, *k), buf.buf))))
 648                         do_update = true;
 649
 650                 if (data_type != BCH_DATA_btree && p.ptr.gen != g->gen)
 651                         continue;
 652
 653                 if (fsck_err_on(bucket_data_type(g->data_type) &&
 654                                 bucket_data_type(g->data_type) != data_type, c,
 655                                 ptr_bucket_data_type_mismatch,
 656                                 "bucket %u:%zu different types of data in same bucket: %s, %s\n"
 657                                 "while marking %s",
 658                                 p.ptr.dev, PTR_BUCKET_NR(ca, &p.ptr),
 659                                 bch2_data_types[g->data_type],
 660                                 bch2_data_types[data_type],
 661                                 (printbuf_reset(&buf),
 662                                  bch2_bkey_val_to_text(&buf, c, *k), buf.buf))) {
 663                         if (data_type == BCH_DATA_btree) {
 664                                 g->data_type    = data_type;
 665                                 set_bit(BCH_FS_need_another_gc, &c->flags);
 666                         } else {
 667                                 do_update = true;
 668                         }
 669                 }
 670
 671                 if (p.has_ec) {
 672                         struct gc_stripe *m = genradix_ptr(&c->gc_stripes, p.ec.idx);
 673
 674                         if (fsck_err_on(!m || !m->alive, c,
 675                                         ptr_to_missing_stripe,
 676                                         "pointer to nonexistent stripe %llu\n"
 677                                         "while marking %s",
 678                                         (u64) p.ec.idx,
 679                                         (printbuf_reset(&buf),
 680                                          bch2_bkey_val_to_text(&buf, c, *k), buf.buf)))
 681                                 do_update = true;
 682
 683                         if (fsck_err_on(m && m->alive && !bch2_ptr_matches_stripe_m(m, p), c,
 684                                         ptr_to_incorrect_stripe,
 685                                         "pointer does not match stripe %llu\n"
 686                                         "while marking %s",
 687                                         (u64) p.ec.idx,
 688                                         (printbuf_reset(&buf),
 689                                          bch2_bkey_val_to_text(&buf, c, *k), buf.buf)))
 690                                 do_update = true;
 691                 }
 692         }
 693
 694         if (do_update) {
 695                 struct bkey_ptrs ptrs;
 696                 union bch_extent_entry *entry;
 697                 struct bch_extent_ptr *ptr;
 698                 struct bkey_i *new;
 699
 700                 if (is_root) {
 701                         bch_err(c, "cannot update btree roots yet");
 702                         ret = -EINVAL;
 703                         goto err;
 704                 }
 705
 706                 new = kmalloc(bkey_bytes(k->k), GFP_KERNEL);
 707                 if (!new) {
 708                         ret = -BCH_ERR_ENOMEM_gc_repair_key;
 709                         bch_err_msg(c, ret, "allocating new key");
 710                         goto err;
 711                 }
 712
 713                 bkey_reassemble(new, *k);
 714
 715                 if (level) {
 716                         /*
 717                          * We don't want to drop btree node pointers - if the
 718                          * btree node isn't there anymore, the read path will
 719                          * sort it out:
 720                          */
 721                         ptrs = bch2_bkey_ptrs(bkey_i_to_s(new));
 722                         bkey_for_each_ptr(ptrs, ptr) {
 723                                 struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
 724                                 struct bucket *g = PTR_GC_BUCKET(ca, ptr);
 725
 726                                 ptr->gen = g->gen;
 727                         }
 728                 } else {
 729                         bch2_bkey_drop_ptrs(bkey_i_to_s(new), ptr, ({
 730                                 struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
 731                                 struct bucket *g = PTR_GC_BUCKET(ca, ptr);
 732                                 enum bch_data_type data_type = bch2_bkey_ptr_data_type(*k, ptr);
 733
 734                                 (ptr->cached &&
 735                                  (!g->gen_valid || gen_cmp(ptr->gen, g->gen) > 0)) ||
 736                                 (!ptr->cached &&
 737                                  gen_cmp(ptr->gen, g->gen) < 0) ||
 738                                 gen_cmp(g->gen, ptr->gen) > BUCKET_GC_GEN_MAX ||
 739                                 (g->data_type &&
 740                                  g->data_type != data_type);
 741                         }));
 742 again:
 743                         ptrs = bch2_bkey_ptrs(bkey_i_to_s(new));
 744                         bkey_extent_entry_for_each(ptrs, entry) {
 745                                 if (extent_entry_type(entry) == BCH_EXTENT_ENTRY_stripe_ptr) {
 746                                         struct gc_stripe *m = genradix_ptr(&c->gc_stripes,
 747                                                                         entry->stripe_ptr.idx);
 748                                         union bch_extent_entry *next_ptr;
 749
 750                                         bkey_extent_entry_for_each_from(ptrs, next_ptr, entry)
 751                                                 if (extent_entry_type(next_ptr) == BCH_EXTENT_ENTRY_ptr)
 752                                                         goto found;
 753                                         next_ptr = NULL;
 754 found:
 755                                         if (!next_ptr) {
 756                                                 bch_err(c, "aieee, found stripe ptr with no data ptr");
 757                                                 continue;
 758                                         }
 759
 760                                         if (!m || !m->alive ||
 761                                             !__bch2_ptr_matches_stripe(&m->ptrs[entry->stripe_ptr.block],
 762                                                                        &next_ptr->ptr,
 763                                                                        m->sectors)) {
 764                                                 bch2_bkey_extent_entry_drop(new, entry);
 765                                                 goto again;
 766                                         }
 767                                 }
 768                         }
 769                 }
 770
 771                 ret = bch2_journal_key_insert_take(c, btree_id, level, new);
 772                 if (ret) {
 773                         kfree(new);
 774                         goto err;
 775                 }
 776
 777                 if (level)
 778                         bch2_btree_node_update_key_early(trans, btree_id, level - 1, *k, new);
 779
 780                 if (0) {
 781                         printbuf_reset(&buf);
 782                         bch2_bkey_val_to_text(&buf, c, *k);
 783                         bch_info(c, "updated %s", buf.buf);
 784
 785                         printbuf_reset(&buf);
 786                         bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(new));
 787                         bch_info(c, "new key %s", buf.buf);
 788                 }
 789
 790                 *k = bkey_i_to_s_c(new);
 791         }
 792 err:
 793 fsck_err:
 794         printbuf_exit(&buf);
 795         return ret;
 796 }
 797
 798 /* marking of btree keys/nodes: */
 799
 800 static int bch2_gc_mark_key(struct btree_trans *trans, enum btree_id btree_id,
 801                             unsigned level, bool is_root,
 802                             struct bkey_s_c *k,
 803                             bool initial)
 804 {
 805         struct bch_fs *c = trans->c;
 806         struct bkey deleted = KEY(0, 0, 0);
 807         struct bkey_s_c old = (struct bkey_s_c) { &deleted, NULL };
 808         unsigned flags =
 809                 BTREE_TRIGGER_GC|
 810                 (initial ? BTREE_TRIGGER_NOATOMIC : 0);
 811         int ret = 0;
 812
 813         deleted.p = k->k->p;
 814
 815         if (initial) {
 816                 BUG_ON(bch2_journal_seq_verify &&
 817                        k->k->version.lo > atomic64_read(&c->journal.seq));
 818
 819                 ret = bch2_check_fix_ptrs(trans, btree_id, level, is_root, k);
 820                 if (ret)
 821                         goto err;
 822
 823                 if (fsck_err_on(k->k->version.lo > atomic64_read(&c->key_version), c,
 824                                 bkey_version_in_future,
 825                                 "key version number higher than recorded: %llu > %llu",
 826                                 k->k->version.lo,
 827                                 atomic64_read(&c->key_version)))
 828                         atomic64_set(&c->key_version, k->k->version.lo);
 829         }
 830
 831         ret = commit_do(trans, NULL, NULL, 0,
 832                         bch2_mark_key(trans, btree_id, level, old, *k, flags));
 833 fsck_err:
 834 err:
 835         bch_err_fn(c, ret);
 836         return ret;
 837 }
 838
 839 static int btree_gc_mark_node(struct btree_trans *trans, struct btree *b, bool initial)
 840 {
 841         struct bch_fs *c = trans->c;
 842         struct btree_node_iter iter;
 843         struct bkey unpacked;
 844         struct bkey_s_c k;
 845         struct bkey_buf prev, cur;
 846         int ret = 0;
 847
 848         if (!btree_node_type_needs_gc(btree_node_type(b)))
 849                 return 0;
 850
 851         bch2_btree_node_iter_init_from_start(&iter, b);
 852         bch2_bkey_buf_init(&prev);
 853         bch2_bkey_buf_init(&cur);
 854         bkey_init(&prev.k->k);
 855
 856         while ((k = bch2_btree_node_iter_peek_unpack(&iter, b, &unpacked)).k) {
 857                 ret = bch2_gc_mark_key(trans, b->c.btree_id, b->c.level, false,
 858                                        &k, initial);
 859                 if (ret)
 860                         break;
 861
 862                 bch2_btree_node_iter_advance(&iter, b);
 863
 864                 if (b->c.level) {
 865                         bch2_bkey_buf_reassemble(&cur, c, k);
 866
 867                         ret = bch2_gc_check_topology(c, b, &prev, cur,
 868                                         bch2_btree_node_iter_end(&iter));
 869                         if (ret)
 870                                 break;
 871                 }
 872         }
 873
 874         bch2_bkey_buf_exit(&cur, c);
 875         bch2_bkey_buf_exit(&prev, c);
 876         return ret;
 877 }
 878
 879 static int bch2_gc_btree(struct btree_trans *trans, enum btree_id btree_id,
 880                          bool initial, bool metadata_only)
 881 {
 882         struct bch_fs *c = trans->c;
 883         struct btree_iter iter;
 884         struct btree *b;
 885         unsigned depth = metadata_only ? 1 : 0;
 886         int ret = 0;
 887
 888         gc_pos_set(c, gc_pos_btree(btree_id, POS_MIN, 0));
 889
 890         __for_each_btree_node(trans, iter, btree_id, POS_MIN,
 891                               0, depth, BTREE_ITER_PREFETCH, b, ret) {
 892                 bch2_verify_btree_nr_keys(b);
 893
 894                 gc_pos_set(c, gc_pos_btree_node(b));
 895
 896                 ret = btree_gc_mark_node(trans, b, initial);
 897                 if (ret)
 898                         break;
 899         }
 900         bch2_trans_iter_exit(trans, &iter);
 901
 902         if (ret)
 903                 return ret;
 904
 905         mutex_lock(&c->btree_root_lock);
 906         b = bch2_btree_id_root(c, btree_id)->b;
 907         if (!btree_node_fake(b)) {
 908                 struct bkey_s_c k = bkey_i_to_s_c(&b->key);
 909
 910                 ret = bch2_gc_mark_key(trans, b->c.btree_id, b->c.level + 1,
 911                                        true, &k, initial);
 912         }
 913         gc_pos_set(c, gc_pos_btree_root(b->c.btree_id));
 914         mutex_unlock(&c->btree_root_lock);
 915
 916         return ret;
 917 }
 918
 919 static int bch2_gc_btree_init_recurse(struct btree_trans *trans, struct btree *b,
 920                                       unsigned target_depth)
 921 {
 922         struct bch_fs *c = trans->c;
 923         struct btree_and_journal_iter iter;
 924         struct bkey_s_c k;
 925         struct bkey_buf cur, prev;
 926         struct printbuf buf = PRINTBUF;
 927         int ret = 0;
 928
 929         bch2_btree_and_journal_iter_init_node_iter(&iter, c, b);
 930         bch2_bkey_buf_init(&prev);
 931         bch2_bkey_buf_init(&cur);
 932         bkey_init(&prev.k->k);
 933
 934         while ((k = bch2_btree_and_journal_iter_peek(&iter)).k) {
 935                 BUG_ON(bpos_lt(k.k->p, b->data->min_key));
 936                 BUG_ON(bpos_gt(k.k->p, b->data->max_key));
 937
 938                 ret = bch2_gc_mark_key(trans, b->c.btree_id, b->c.level,
 939                                        false, &k, true);
 940                 if (ret)
 941                         goto fsck_err;
 942
 943                 if (b->c.level) {
 944                         bch2_bkey_buf_reassemble(&cur, c, k);
 945                         k = bkey_i_to_s_c(cur.k);
 946
 947                         bch2_btree_and_journal_iter_advance(&iter);
 948
 949                         ret = bch2_gc_check_topology(c, b,
 950                                         &prev, cur,
 951                                         !bch2_btree_and_journal_iter_peek(&iter).k);
 952                         if (ret)
 953                                 goto fsck_err;
 954                 } else {
 955                         bch2_btree_and_journal_iter_advance(&iter);
 956                 }
 957         }
 958
 959         if (b->c.level > target_depth) {
 960                 bch2_btree_and_journal_iter_exit(&iter);
 961                 bch2_btree_and_journal_iter_init_node_iter(&iter, c, b);
 962
 963                 while ((k = bch2_btree_and_journal_iter_peek(&iter)).k) {
 964                         struct btree *child;
 965
 966                         bch2_bkey_buf_reassemble(&cur, c, k);
 967                         bch2_btree_and_journal_iter_advance(&iter);
 968
 969                         child = bch2_btree_node_get_noiter(trans, cur.k,
 970                                                 b->c.btree_id, b->c.level - 1,
 971                                                 false);
 972                         ret = PTR_ERR_OR_ZERO(child);
 973
 974                         if (ret == -EIO) {
 975                                 bch2_topology_error(c);
 976
 977                                 if (__fsck_err(c,
 978                                           FSCK_CAN_FIX|
 979                                           FSCK_CAN_IGNORE|
 980                                           FSCK_NO_RATELIMIT,
 981                                           btree_node_read_error,
 982                                           "Unreadable btree node at btree %s level %u:\n"
 983                                           "  %s",
 984                                           bch2_btree_id_str(b->c.btree_id),
 985                                           b->c.level - 1,
 986                                           (printbuf_reset(&buf),
 987                                            bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(cur.k)), buf.buf)) &&
 988                                     should_restart_for_topology_repair(c)) {
 989                                         bch_info(c, "Halting mark and sweep to start topology repair pass");
 990                                         ret = bch2_run_explicit_recovery_pass(c, BCH_RECOVERY_PASS_check_topology);
 991                                         goto fsck_err;
 992                                 } else {
 993                                         /* Continue marking when opted to not
 994                                          * fix the error: */
 995                                         ret = 0;
 996                                         set_bit(BCH_FS_initial_gc_unfixed, &c->flags);
 997                                         continue;
 998                                 }
 999                         } else if (ret) {
1000                                 bch_err_msg(c, ret, "getting btree node");
1001                                 break;
1002                         }
1003
1004                         ret = bch2_gc_btree_init_recurse(trans, child,
1005                                                          target_depth);
1006                         six_unlock_read(&child->c.lock);
1007
1008                         if (ret)
1009                                 break;
1010                 }
1011         }
1012 fsck_err:
1013         bch2_bkey_buf_exit(&cur, c);
1014         bch2_bkey_buf_exit(&prev, c);
1015         bch2_btree_and_journal_iter_exit(&iter);
1016         printbuf_exit(&buf);
1017         return ret;
1018 }
1019
1020 static int bch2_gc_btree_init(struct btree_trans *trans,
1021                               enum btree_id btree_id,
1022                               bool metadata_only)
1023 {
1024         struct bch_fs *c = trans->c;
1025         struct btree *b;
1026         unsigned target_depth = metadata_only ? 1 : 0;
1027         struct printbuf buf = PRINTBUF;
1028         int ret = 0;
1029
1030         b = bch2_btree_id_root(c, btree_id)->b;
1031
1032         if (btree_node_fake(b))
1033                 return 0;
1034
1035         six_lock_read(&b->c.lock, NULL, NULL);
1036         printbuf_reset(&buf);
1037         bch2_bpos_to_text(&buf, b->data->min_key);
1038         if (mustfix_fsck_err_on(!bpos_eq(b->data->min_key, POS_MIN), c,
1039                                 btree_root_bad_min_key,
1040                         "btree root with incorrect min_key: %s", buf.buf)) {
1041                 bch_err(c, "repair unimplemented");
1042                 ret = -BCH_ERR_fsck_repair_unimplemented;
1043                 goto fsck_err;
1044         }
1045
1046         printbuf_reset(&buf);
1047         bch2_bpos_to_text(&buf, b->data->max_key);
1048         if (mustfix_fsck_err_on(!bpos_eq(b->data->max_key, SPOS_MAX), c,
1049                                 btree_root_bad_max_key,
1050                         "btree root with incorrect max_key: %s", buf.buf)) {
1051                 bch_err(c, "repair unimplemented");
1052                 ret = -BCH_ERR_fsck_repair_unimplemented;
1053                 goto fsck_err;
1054         }
1055
1056         if (b->c.level >= target_depth)
1057                 ret = bch2_gc_btree_init_recurse(trans, b, target_depth);
1058
1059         if (!ret) {
1060                 struct bkey_s_c k = bkey_i_to_s_c(&b->key);
1061
1062                 ret = bch2_gc_mark_key(trans, b->c.btree_id, b->c.level + 1, true,
1063                                        &k, true);
1064         }
1065 fsck_err:
1066         six_unlock_read(&b->c.lock);
1067
1068         bch_err_fn(c, ret);
1069         printbuf_exit(&buf);
1070         return ret;
1071 }
1072
1073 static inline int btree_id_gc_phase_cmp(enum btree_id l, enum btree_id r)
1074 {
1075         return  (int) btree_id_to_gc_phase(l) -
1076                 (int) btree_id_to_gc_phase(r);
1077 }
1078
1079 static int bch2_gc_btrees(struct bch_fs *c, bool initial, bool metadata_only)
1080 {
1081         struct btree_trans *trans = bch2_trans_get(c);
1082         enum btree_id ids[BTREE_ID_NR];
1083         unsigned i;
1084         int ret = 0;
1085
1086         for (i = 0; i < BTREE_ID_NR; i++)
1087                 ids[i] = i;
1088         bubble_sort(ids, BTREE_ID_NR, btree_id_gc_phase_cmp);
1089
1090         for (i = 0; i < BTREE_ID_NR && !ret; i++)
1091                 ret = initial
1092                         ? bch2_gc_btree_init(trans, ids[i], metadata_only)
1093                         : bch2_gc_btree(trans, ids[i], initial, metadata_only);
1094
1095         for (i = BTREE_ID_NR; i < btree_id_nr_alive(c) && !ret; i++) {
1096                 if (!bch2_btree_id_root(c, i)->alive)
1097                         continue;
1098
1099                 ret = initial
1100                         ? bch2_gc_btree_init(trans, i, metadata_only)
1101                         : bch2_gc_btree(trans, i, initial, metadata_only);
1102         }
1103
1104         bch2_trans_put(trans);
1105         bch_err_fn(c, ret);
1106         return ret;
1107 }
1108
1109 static void mark_metadata_sectors(struct bch_fs *c, struct bch_dev *ca,
1110                                   u64 start, u64 end,
1111                                   enum bch_data_type type,
1112                                   unsigned flags)
1113 {
1114         u64 b = sector_to_bucket(ca, start);
1115
1116         do {
1117                 unsigned sectors =
1118                         min_t(u64, bucket_to_sector(ca, b + 1), end) - start;
1119
1120                 bch2_mark_metadata_bucket(c, ca, b, type, sectors,
1121                                           gc_phase(GC_PHASE_SB), flags);
1122                 b++;
1123                 start += sectors;
1124         } while (start < end);
1125 }
1126
1127 static void bch2_mark_dev_superblock(struct bch_fs *c, struct bch_dev *ca,
1128                                      unsigned flags)
1129 {
1130         struct bch_sb_layout *layout = &ca->disk_sb.sb->layout;
1131         unsigned i;
1132         u64 b;
1133
1134         for (i = 0; i < layout->nr_superblocks; i++) {
1135                 u64 offset = le64_to_cpu(layout->sb_offset[i]);
1136
1137                 if (offset == BCH_SB_SECTOR)
1138                         mark_metadata_sectors(c, ca, 0, BCH_SB_SECTOR,
1139                                               BCH_DATA_sb, flags);
1140
1141                 mark_metadata_sectors(c, ca, offset,
1142                                       offset + (1 << layout->sb_max_size_bits),
1143                                       BCH_DATA_sb, flags);
1144         }
1145
1146         for (i = 0; i < ca->journal.nr; i++) {
1147                 b = ca->journal.buckets[i];
1148                 bch2_mark_metadata_bucket(c, ca, b, BCH_DATA_journal,
1149                                           ca->mi.bucket_size,
1150                                           gc_phase(GC_PHASE_SB), flags);
1151         }
1152 }
1153
1154 static void bch2_mark_superblocks(struct bch_fs *c)
1155 {
1156         mutex_lock(&c->sb_lock);
1157         gc_pos_set(c, gc_phase(GC_PHASE_SB));
1158
1159         for_each_online_member(c, ca)
1160                 bch2_mark_dev_superblock(c, ca, BTREE_TRIGGER_GC);
1161         mutex_unlock(&c->sb_lock);
1162 }
1163
1164 #if 0
1165 /* Also see bch2_pending_btree_node_free_insert_done() */
1166 static void bch2_mark_pending_btree_node_frees(struct bch_fs *c)
1167 {
1168         struct btree_update *as;
1169         struct pending_btree_node_free *d;
1170
1171         mutex_lock(&c->btree_interior_update_lock);
1172         gc_pos_set(c, gc_phase(GC_PHASE_PENDING_DELETE));
1173
1174         for_each_pending_btree_node_free(c, as, d)
1175                 if (d->index_update_done)
1176                         bch2_mark_key(c, bkey_i_to_s_c(&d->key), BTREE_TRIGGER_GC);
1177
1178         mutex_unlock(&c->btree_interior_update_lock);
1179 }
1180 #endif
1181
1182 static void bch2_gc_free(struct bch_fs *c)
1183 {
1184         genradix_free(&c->reflink_gc_table);
1185         genradix_free(&c->gc_stripes);
1186
1187         for_each_member_device(c, ca) {
1188                 kvpfree(rcu_dereference_protected(ca->buckets_gc, 1),
1189                         sizeof(struct bucket_array) +
1190                         ca->mi.nbuckets * sizeof(struct bucket));
1191                 ca->buckets_gc = NULL;
1192
1193                 free_percpu(ca->usage_gc);
1194                 ca->usage_gc = NULL;
1195         }
1196
1197         free_percpu(c->usage_gc);
1198         c->usage_gc = NULL;
1199 }
1200
1201 static int bch2_gc_done(struct bch_fs *c,
1202                         bool initial, bool metadata_only)
1203 {
1204         struct bch_dev *ca = NULL;
1205         struct printbuf buf = PRINTBUF;
1206         bool verify = !metadata_only &&
1207                 !c->opts.reconstruct_alloc &&
1208                 (!initial || (c->sb.compat & (1ULL << BCH_COMPAT_alloc_info)));
1209         unsigned i;
1210         int ret = 0;
1211
1212         percpu_down_write(&c->mark_lock);
1213
1214 #define copy_field(_err, _f, _msg, ...)                                 \
1215         if (dst->_f != src->_f &&                                       \
1216             (!verify ||                                                 \
1217              fsck_err(c, _err, _msg ": got %llu, should be %llu"        \
1218                       , ##__VA_ARGS__, dst->_f, src->_f)))              \
1219                 dst->_f = src->_f
1220 #define copy_dev_field(_err, _f, _msg, ...)                             \
1221         copy_field(_err, _f, "dev %u has wrong " _msg, ca->dev_idx, ##__VA_ARGS__)
1222 #define copy_fs_field(_err, _f, _msg, ...)                              \
1223         copy_field(_err, _f, "fs has wrong " _msg, ##__VA_ARGS__)
1224
1225         for (i = 0; i < ARRAY_SIZE(c->usage); i++)
1226                 bch2_fs_usage_acc_to_base(c, i);
1227
1228         __for_each_member_device(c, ca) {
1229                 struct bch_dev_usage *dst = ca->usage_base;
1230                 struct bch_dev_usage *src = (void *)
1231                         bch2_acc_percpu_u64s((u64 __percpu *) ca->usage_gc,
1232                                              dev_usage_u64s());
1233
1234                 for (i = 0; i < BCH_DATA_NR; i++) {
1235                         copy_dev_field(dev_usage_buckets_wrong,
1236                                        d[i].buckets,    "%s buckets", bch2_data_types[i]);
1237                         copy_dev_field(dev_usage_sectors_wrong,
1238                                        d[i].sectors,    "%s sectors", bch2_data_types[i]);
1239                         copy_dev_field(dev_usage_fragmented_wrong,
1240                                        d[i].fragmented, "%s fragmented", bch2_data_types[i]);
1241                 }
1242         }
1243
1244         {
1245                 unsigned nr = fs_usage_u64s(c);
1246                 struct bch_fs_usage *dst = c->usage_base;
1247                 struct bch_fs_usage *src = (void *)
1248                         bch2_acc_percpu_u64s((u64 __percpu *) c->usage_gc, nr);
1249
1250                 copy_fs_field(fs_usage_hidden_wrong,
1251                               hidden,           "hidden");
1252                 copy_fs_field(fs_usage_btree_wrong,
1253                               btree,            "btree");
1254
1255                 if (!metadata_only) {
1256                         copy_fs_field(fs_usage_data_wrong,
1257                                       data,     "data");
1258                         copy_fs_field(fs_usage_cached_wrong,
1259                                       cached,   "cached");
1260                         copy_fs_field(fs_usage_reserved_wrong,
1261                                       reserved, "reserved");
1262                         copy_fs_field(fs_usage_nr_inodes_wrong,
1263                                       nr_inodes,"nr_inodes");
1264
1265                         for (i = 0; i < BCH_REPLICAS_MAX; i++)
1266                                 copy_fs_field(fs_usage_persistent_reserved_wrong,
1267                                               persistent_reserved[i],
1268                                               "persistent_reserved[%i]", i);
1269                 }
1270
1271                 for (i = 0; i < c->replicas.nr; i++) {
1272                         struct bch_replicas_entry_v1 *e =
1273                                 cpu_replicas_entry(&c->replicas, i);
1274
1275                         if (metadata_only &&
1276                             (e->data_type == BCH_DATA_user ||
1277                              e->data_type == BCH_DATA_cached))
1278                                 continue;
1279
1280                         printbuf_reset(&buf);
1281                         bch2_replicas_entry_to_text(&buf, e);
1282
1283                         copy_fs_field(fs_usage_replicas_wrong,
1284                                       replicas[i], "%s", buf.buf);
1285                 }
1286         }
1287
1288 #undef copy_fs_field
1289 #undef copy_dev_field
1290 #undef copy_stripe_field
1291 #undef copy_field
1292 fsck_err:
1293         if (ca)
1294                 percpu_ref_put(&ca->ref);
1295         bch_err_fn(c, ret);
1296
1297         percpu_up_write(&c->mark_lock);
1298         printbuf_exit(&buf);
1299         return ret;
1300 }
1301
1302 static int bch2_gc_start(struct bch_fs *c)
1303 {
1304         BUG_ON(c->usage_gc);
1305
1306         c->usage_gc = __alloc_percpu_gfp(fs_usage_u64s(c) * sizeof(u64),
1307                                          sizeof(u64), GFP_KERNEL);
1308         if (!c->usage_gc) {
1309                 bch_err(c, "error allocating c->usage_gc");
1310                 return -BCH_ERR_ENOMEM_gc_start;
1311         }
1312
1313         for_each_member_device(c, ca) {
1314                 BUG_ON(ca->usage_gc);
1315
1316                 ca->usage_gc = alloc_percpu(struct bch_dev_usage);
1317                 if (!ca->usage_gc) {
1318                         bch_err(c, "error allocating ca->usage_gc");
1319                         percpu_ref_put(&ca->ref);
1320                         return -BCH_ERR_ENOMEM_gc_start;
1321                 }
1322
1323                 this_cpu_write(ca->usage_gc->d[BCH_DATA_free].buckets,
1324                                ca->mi.nbuckets - ca->mi.first_bucket);
1325         }
1326
1327         return 0;
1328 }
1329
1330 static int bch2_gc_reset(struct bch_fs *c)
1331 {
1332         for_each_member_device(c, ca) {
1333                 free_percpu(ca->usage_gc);
1334                 ca->usage_gc = NULL;
1335         }
1336
1337         free_percpu(c->usage_gc);
1338         c->usage_gc = NULL;
1339
1340         return bch2_gc_start(c);
1341 }
1342
1343 /* returns true if not equal */
1344 static inline bool bch2_alloc_v4_cmp(struct bch_alloc_v4 l,
1345                                      struct bch_alloc_v4 r)
1346 {
1347         return  l.gen != r.gen                          ||
1348                 l.oldest_gen != r.oldest_gen            ||
1349                 l.data_type != r.data_type              ||
1350                 l.dirty_sectors != r.dirty_sectors      ||
1351                 l.cached_sectors != r.cached_sectors     ||
1352                 l.stripe_redundancy != r.stripe_redundancy ||
1353                 l.stripe != r.stripe;
1354 }
1355
1356 static int bch2_alloc_write_key(struct btree_trans *trans,
1357                                 struct btree_iter *iter,
1358                                 struct bkey_s_c k,
1359                                 bool metadata_only)
1360 {
1361         struct bch_fs *c = trans->c;
1362         struct bch_dev *ca = bch_dev_bkey_exists(c, iter->pos.inode);
1363         struct bucket gc, *b;
1364         struct bkey_i_alloc_v4 *a;
1365         struct bch_alloc_v4 old_convert, new;
1366         const struct bch_alloc_v4 *old;
1367         enum bch_data_type type;
1368         int ret;
1369
1370         old = bch2_alloc_to_v4(k, &old_convert);
1371         new = *old;
1372
1373         percpu_down_read(&c->mark_lock);
1374         b = gc_bucket(ca, iter->pos.offset);
1375
1376         /*
1377          * b->data_type doesn't yet include need_discard & need_gc_gen states -
1378          * fix that here:
1379          */
1380         type = __alloc_data_type(b->dirty_sectors,
1381                                  b->cached_sectors,
1382                                  b->stripe,
1383                                  *old,
1384                                  b->data_type);
1385         if (b->data_type != type) {
1386                 struct bch_dev_usage *u;
1387
1388                 preempt_disable();
1389                 u = this_cpu_ptr(ca->usage_gc);
1390                 u->d[b->data_type].buckets--;
1391                 b->data_type = type;
1392                 u->d[b->data_type].buckets++;
1393                 preempt_enable();
1394         }
1395
1396         gc = *b;
1397         percpu_up_read(&c->mark_lock);
1398
1399         if (metadata_only &&
1400             gc.data_type != BCH_DATA_sb &&
1401             gc.data_type != BCH_DATA_journal &&
1402             gc.data_type != BCH_DATA_btree)
1403                 return 0;
1404
1405         if (gen_after(old->gen, gc.gen))
1406                 return 0;
1407
1408         if (c->opts.reconstruct_alloc ||
1409             fsck_err_on(new.data_type != gc.data_type, c,
1410                         alloc_key_data_type_wrong,
1411                         "bucket %llu:%llu gen %u has wrong data_type"
1412                         ": got %s, should be %s",
1413                         iter->pos.inode, iter->pos.offset,
1414                         gc.gen,
1415                         bch2_data_types[new.data_type],
1416                         bch2_data_types[gc.data_type]))
1417                 new.data_type = gc.data_type;
1418
1419 #define copy_bucket_field(_errtype, _f)                                 \
1420         if (c->opts.reconstruct_alloc ||                                \
1421             fsck_err_on(new._f != gc._f, c, _errtype,                   \
1422                         "bucket %llu:%llu gen %u data type %s has wrong " #_f   \
1423                         ": got %u, should be %u",                       \
1424                         iter->pos.inode, iter->pos.offset,              \
1425                         gc.gen,                                         \
1426                         bch2_data_types[gc.data_type],                  \
1427                         new._f, gc._f))                                 \
1428                 new._f = gc._f;                                         \
1429
1430         copy_bucket_field(alloc_key_gen_wrong,
1431                           gen);
1432         copy_bucket_field(alloc_key_dirty_sectors_wrong,
1433                           dirty_sectors);
1434         copy_bucket_field(alloc_key_cached_sectors_wrong,
1435                           cached_sectors);
1436         copy_bucket_field(alloc_key_stripe_wrong,
1437                           stripe);
1438         copy_bucket_field(alloc_key_stripe_redundancy_wrong,
1439                           stripe_redundancy);
1440 #undef copy_bucket_field
1441
1442         if (!bch2_alloc_v4_cmp(*old, new))
1443                 return 0;
1444
1445         a = bch2_alloc_to_v4_mut(trans, k);
1446         ret = PTR_ERR_OR_ZERO(a);
1447         if (ret)
1448                 return ret;
1449
1450         a->v = new;
1451
1452         /*
1453          * The trigger normally makes sure this is set, but we're not running
1454          * triggers:
1455          */
1456         if (a->v.data_type == BCH_DATA_cached && !a->v.io_time[READ])
1457                 a->v.io_time[READ] = max_t(u64, 1, atomic64_read(&c->io_clock[READ].now));
1458
1459         ret = bch2_trans_update(trans, iter, &a->k_i, BTREE_TRIGGER_NORUN);
1460 fsck_err:
1461         return ret;
1462 }
1463
1464 static int bch2_gc_alloc_done(struct bch_fs *c, bool metadata_only)
1465 {
1466         int ret = 0;
1467
1468         for_each_member_device(c, ca) {
1469                 ret = bch2_trans_run(c,
1470                         for_each_btree_key_upto_commit(trans, iter, BTREE_ID_alloc,
1471                                         POS(ca->dev_idx, ca->mi.first_bucket),
1472                                         POS(ca->dev_idx, ca->mi.nbuckets - 1),
1473                                         BTREE_ITER_SLOTS|BTREE_ITER_PREFETCH, k,
1474                                         NULL, NULL, BCH_TRANS_COMMIT_lazy_rw,
1475                                 bch2_alloc_write_key(trans, &iter, k, metadata_only)));
1476                 if (ret) {
1477                         percpu_ref_put(&ca->ref);
1478                         break;
1479                 }
1480         }
1481
1482         bch_err_fn(c, ret);
1483         return ret;
1484 }
1485
1486 static int bch2_gc_alloc_start(struct bch_fs *c, bool metadata_only)
1487 {
1488         for_each_member_device(c, ca) {
1489                 struct bucket_array *buckets = kvpmalloc(sizeof(struct bucket_array) +
1490                                 ca->mi.nbuckets * sizeof(struct bucket),
1491                                 GFP_KERNEL|__GFP_ZERO);
1492                 if (!buckets) {
1493                         percpu_ref_put(&ca->ref);
1494                         bch_err(c, "error allocating ca->buckets[gc]");
1495                         return -BCH_ERR_ENOMEM_gc_alloc_start;
1496                 }
1497
1498                 buckets->first_bucket   = ca->mi.first_bucket;
1499                 buckets->nbuckets       = ca->mi.nbuckets;
1500                 rcu_assign_pointer(ca->buckets_gc, buckets);
1501         }
1502
1503         int ret = bch2_trans_run(c,
1504                 for_each_btree_key(trans, iter, BTREE_ID_alloc, POS_MIN,
1505                                          BTREE_ITER_PREFETCH, k, ({
1506                         struct bch_dev *ca = bch_dev_bkey_exists(c, k.k->p.inode);
1507                         struct bucket *g = gc_bucket(ca, k.k->p.offset);
1508
1509                         struct bch_alloc_v4 a_convert;
1510                         const struct bch_alloc_v4 *a = bch2_alloc_to_v4(k, &a_convert);
1511
1512                         g->gen_valid    = 1;
1513                         g->gen          = a->gen;
1514
1515                         if (metadata_only &&
1516                             (a->data_type == BCH_DATA_user ||
1517                              a->data_type == BCH_DATA_cached ||
1518                              a->data_type == BCH_DATA_parity)) {
1519                                 g->data_type            = a->data_type;
1520                                 g->dirty_sectors        = a->dirty_sectors;
1521                                 g->cached_sectors       = a->cached_sectors;
1522                                 g->stripe               = a->stripe;
1523                                 g->stripe_redundancy    = a->stripe_redundancy;
1524                         }
1525
1526                         0;
1527                 })));
1528         bch_err_fn(c, ret);
1529         return ret;
1530 }
1531
1532 static void bch2_gc_alloc_reset(struct bch_fs *c, bool metadata_only)
1533 {
1534         for_each_member_device(c, ca) {
1535                 struct bucket_array *buckets = gc_bucket_array(ca);
1536                 struct bucket *g;
1537
1538                 for_each_bucket(g, buckets) {
1539                         if (metadata_only &&
1540                             (g->data_type == BCH_DATA_user ||
1541                              g->data_type == BCH_DATA_cached ||
1542                              g->data_type == BCH_DATA_parity))
1543                                 continue;
1544                         g->data_type = 0;
1545                         g->dirty_sectors = 0;
1546                         g->cached_sectors = 0;
1547                 }
1548         }
1549 }
1550
1551 static int bch2_gc_write_reflink_key(struct btree_trans *trans,
1552                                      struct btree_iter *iter,
1553                                      struct bkey_s_c k,
1554                                      size_t *idx)
1555 {
1556         struct bch_fs *c = trans->c;
1557         const __le64 *refcount = bkey_refcount_c(k);
1558         struct printbuf buf = PRINTBUF;
1559         struct reflink_gc *r;
1560         int ret = 0;
1561
1562         if (!refcount)
1563                 return 0;
1564
1565         while ((r = genradix_ptr(&c->reflink_gc_table, *idx)) &&
1566                r->offset < k.k->p.offset)
1567                 ++*idx;
1568
1569         if (!r ||
1570             r->offset != k.k->p.offset ||
1571             r->size != k.k->size) {
1572                 bch_err(c, "unexpected inconsistency walking reflink table at gc finish");
1573                 return -EINVAL;
1574         }
1575
1576         if (fsck_err_on(r->refcount != le64_to_cpu(*refcount), c,
1577                         reflink_v_refcount_wrong,
1578                         "reflink key has wrong refcount:\n"
1579                         "  %s\n"
1580                         "  should be %u",
1581                         (bch2_bkey_val_to_text(&buf, c, k), buf.buf),
1582                         r->refcount)) {
1583                 struct bkey_i *new = bch2_bkey_make_mut(trans, iter, &k, 0);
1584
1585                 ret = PTR_ERR_OR_ZERO(new);
1586                 if (ret)
1587                         return ret;
1588
1589                 if (!r->refcount)
1590                         new->k.type = KEY_TYPE_deleted;
1591                 else
1592                         *bkey_refcount(new) = cpu_to_le64(r->refcount);
1593         }
1594 fsck_err:
1595         printbuf_exit(&buf);
1596         return ret;
1597 }
1598
1599 static int bch2_gc_reflink_done(struct bch_fs *c, bool metadata_only)
1600 {
1601         size_t idx = 0;
1602
1603         if (metadata_only)
1604                 return 0;
1605
1606         int ret = bch2_trans_run(c,
1607                 for_each_btree_key_commit(trans, iter,
1608                                 BTREE_ID_reflink, POS_MIN,
1609                                 BTREE_ITER_PREFETCH, k,
1610                                 NULL, NULL, BCH_TRANS_COMMIT_no_enospc,
1611                         bch2_gc_write_reflink_key(trans, &iter, k, &idx)));
1612         c->reflink_gc_nr = 0;
1613         return ret;
1614 }
1615
1616 static int bch2_gc_reflink_start(struct bch_fs *c,
1617                                  bool metadata_only)
1618 {
1619
1620         if (metadata_only)
1621                 return 0;
1622
1623         c->reflink_gc_nr = 0;
1624
1625         int ret = bch2_trans_run(c,
1626                 for_each_btree_key(trans, iter, BTREE_ID_reflink, POS_MIN,
1627                                    BTREE_ITER_PREFETCH, k, ({
1628                         const __le64 *refcount = bkey_refcount_c(k);
1629
1630                         if (!refcount)
1631                                 continue;
1632
1633                         struct reflink_gc *r = genradix_ptr_alloc(&c->reflink_gc_table,
1634                                                         c->reflink_gc_nr++, GFP_KERNEL);
1635                         if (!r) {
1636                                 ret = -BCH_ERR_ENOMEM_gc_reflink_start;
1637                                 break;
1638                         }
1639
1640                         r->offset       = k.k->p.offset;
1641                         r->size         = k.k->size;
1642                         r->refcount     = 0;
1643                         0;
1644                 })));
1645
1646         bch_err_fn(c, ret);
1647         return ret;
1648 }
1649
1650 static void bch2_gc_reflink_reset(struct bch_fs *c, bool metadata_only)
1651 {
1652         struct genradix_iter iter;
1653         struct reflink_gc *r;
1654
1655         genradix_for_each(&c->reflink_gc_table, iter, r)
1656                 r->refcount = 0;
1657 }
1658
1659 static int bch2_gc_write_stripes_key(struct btree_trans *trans,
1660                                      struct btree_iter *iter,
1661                                      struct bkey_s_c k)
1662 {
1663         struct bch_fs *c = trans->c;
1664         struct printbuf buf = PRINTBUF;
1665         const struct bch_stripe *s;
1666         struct gc_stripe *m;
1667         bool bad = false;
1668         unsigned i;
1669         int ret = 0;
1670
1671         if (k.k->type != KEY_TYPE_stripe)
1672                 return 0;
1673
1674         s = bkey_s_c_to_stripe(k).v;
1675         m = genradix_ptr(&c->gc_stripes, k.k->p.offset);
1676
1677         for (i = 0; i < s->nr_blocks; i++) {
1678                 u32 old = stripe_blockcount_get(s, i);
1679                 u32 new = (m ? m->block_sectors[i] : 0);
1680
1681                 if (old != new) {
1682                         prt_printf(&buf, "stripe block %u has wrong sector count: got %u, should be %u\n",
1683                                    i, old, new);
1684                         bad = true;
1685                 }
1686         }
1687
1688         if (bad)
1689                 bch2_bkey_val_to_text(&buf, c, k);
1690
1691         if (fsck_err_on(bad, c, stripe_sector_count_wrong,
1692                         "%s", buf.buf)) {
1693                 struct bkey_i_stripe *new;
1694
1695                 new = bch2_trans_kmalloc(trans, bkey_bytes(k.k));
1696                 ret = PTR_ERR_OR_ZERO(new);
1697                 if (ret)
1698                         return ret;
1699
1700                 bkey_reassemble(&new->k_i, k);
1701
1702                 for (i = 0; i < new->v.nr_blocks; i++)
1703                         stripe_blockcount_set(&new->v, i, m ? m->block_sectors[i] : 0);
1704
1705                 ret = bch2_trans_update(trans, iter, &new->k_i, 0);
1706         }
1707 fsck_err:
1708         printbuf_exit(&buf);
1709         return ret;
1710 }
1711
1712 static int bch2_gc_stripes_done(struct bch_fs *c, bool metadata_only)
1713 {
1714         if (metadata_only)
1715                 return 0;
1716
1717         return bch2_trans_run(c,
1718                 for_each_btree_key_commit(trans, iter,
1719                                 BTREE_ID_stripes, POS_MIN,
1720                                 BTREE_ITER_PREFETCH, k,
1721                                 NULL, NULL, BCH_TRANS_COMMIT_no_enospc,
1722                         bch2_gc_write_stripes_key(trans, &iter, k)));
1723 }
1724
1725 static void bch2_gc_stripes_reset(struct bch_fs *c, bool metadata_only)
1726 {
1727         genradix_free(&c->gc_stripes);
1728 }
1729
1730 /**
1731  * bch2_gc - walk _all_ references to buckets, and recompute them:
1732  *
1733  * @c:                  filesystem object
1734  * @initial:            are we in recovery?
1735  * @metadata_only:      are we just checking metadata references, or everything?
1736  *
1737  * Returns: 0 on success, or standard errcode on failure
1738  *
1739  * Order matters here:
1740  *  - Concurrent GC relies on the fact that we have a total ordering for
1741  *    everything that GC walks - see  gc_will_visit_node(),
1742  *    gc_will_visit_root()
1743  *
1744  *  - also, references move around in the course of index updates and
1745  *    various other crap: everything needs to agree on the ordering
1746  *    references are allowed to move around in - e.g., we're allowed to
1747  *    start with a reference owned by an open_bucket (the allocator) and
1748  *    move it to the btree, but not the reverse.
1749  *
1750  *    This is necessary to ensure that gc doesn't miss references that
1751  *    move around - if references move backwards in the ordering GC
1752  *    uses, GC could skip past them
1753  */
1754 int bch2_gc(struct bch_fs *c, bool initial, bool metadata_only)
1755 {
1756         unsigned iter = 0;
1757         int ret;
1758
1759         lockdep_assert_held(&c->state_lock);
1760
1761         down_write(&c->gc_lock);
1762
1763         bch2_btree_interior_updates_flush(c);
1764
1765         ret   = bch2_gc_start(c) ?:
1766                 bch2_gc_alloc_start(c, metadata_only) ?:
1767                 bch2_gc_reflink_start(c, metadata_only);
1768         if (ret)
1769                 goto out;
1770 again:
1771         gc_pos_set(c, gc_phase(GC_PHASE_START));
1772
1773         bch2_mark_superblocks(c);
1774
1775         ret = bch2_gc_btrees(c, initial, metadata_only);
1776
1777         if (ret)
1778                 goto out;
1779
1780 #if 0
1781         bch2_mark_pending_btree_node_frees(c);
1782 #endif
1783         c->gc_count++;
1784
1785         if (test_bit(BCH_FS_need_another_gc, &c->flags) ||
1786             (!iter && bch2_test_restart_gc)) {
1787                 if (iter++ > 2) {
1788                         bch_info(c, "Unable to fix bucket gens, looping");
1789                         ret = -EINVAL;
1790                         goto out;
1791                 }
1792
1793                 /*
1794                  * XXX: make sure gens we fixed got saved
1795                  */
1796                 bch_info(c, "Second GC pass needed, restarting:");
1797                 clear_bit(BCH_FS_need_another_gc, &c->flags);
1798                 __gc_pos_set(c, gc_phase(GC_PHASE_NOT_RUNNING));
1799
1800                 bch2_gc_stripes_reset(c, metadata_only);
1801                 bch2_gc_alloc_reset(c, metadata_only);
1802                 bch2_gc_reflink_reset(c, metadata_only);
1803                 ret = bch2_gc_reset(c);
1804                 if (ret)
1805                         goto out;
1806
1807                 /* flush fsck errors, reset counters */
1808                 bch2_flush_fsck_errs(c);
1809                 goto again;
1810         }
1811 out:
1812         if (!ret) {
1813                 bch2_journal_block(&c->journal);
1814
1815                 ret   = bch2_gc_stripes_done(c, metadata_only) ?:
1816                         bch2_gc_reflink_done(c, metadata_only) ?:
1817                         bch2_gc_alloc_done(c, metadata_only) ?:
1818                         bch2_gc_done(c, initial, metadata_only);
1819
1820                 bch2_journal_unblock(&c->journal);
1821         }
1822
1823         percpu_down_write(&c->mark_lock);
1824         /* Indicates that gc is no longer in progress: */
1825         __gc_pos_set(c, gc_phase(GC_PHASE_NOT_RUNNING));
1826
1827         bch2_gc_free(c);
1828         percpu_up_write(&c->mark_lock);
1829
1830         up_write(&c->gc_lock);
1831
1832         /*
1833          * At startup, allocations can happen directly instead of via the
1834          * allocator thread - issue wakeup in case they blocked on gc_lock:
1835          */
1836         closure_wake_up(&c->freelist_wait);
1837         bch_err_fn(c, ret);
1838         return ret;
1839 }
1840
1841 static int gc_btree_gens_key(struct btree_trans *trans,
1842                              struct btree_iter *iter,
1843                              struct bkey_s_c k)
1844 {
1845         struct bch_fs *c = trans->c;
1846         struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
1847         const struct bch_extent_ptr *ptr;
1848         struct bkey_i *u;
1849         int ret;
1850
1851         percpu_down_read(&c->mark_lock);
1852         bkey_for_each_ptr(ptrs, ptr) {
1853                 struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
1854
1855                 if (ptr_stale(ca, ptr) > 16) {
1856                         percpu_up_read(&c->mark_lock);
1857                         goto update;
1858                 }
1859         }
1860
1861         bkey_for_each_ptr(ptrs, ptr) {
1862                 struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
1863                 u8 *gen = &ca->oldest_gen[PTR_BUCKET_NR(ca, ptr)];
1864
1865                 if (gen_after(*gen, ptr->gen))
1866                         *gen = ptr->gen;
1867         }
1868         percpu_up_read(&c->mark_lock);
1869         return 0;
1870 update:
1871         u = bch2_bkey_make_mut(trans, iter, &k, 0);
1872         ret = PTR_ERR_OR_ZERO(u);
1873         if (ret)
1874                 return ret;
1875
1876         bch2_extent_normalize(c, bkey_i_to_s(u));
1877         return 0;
1878 }
1879
1880 static int bch2_alloc_write_oldest_gen(struct btree_trans *trans, struct btree_iter *iter,
1881                                        struct bkey_s_c k)
1882 {
1883         struct bch_dev *ca = bch_dev_bkey_exists(trans->c, iter->pos.inode);
1884         struct bch_alloc_v4 a_convert;
1885         const struct bch_alloc_v4 *a = bch2_alloc_to_v4(k, &a_convert);
1886         struct bkey_i_alloc_v4 *a_mut;
1887         int ret;
1888
1889         if (a->oldest_gen == ca->oldest_gen[iter->pos.offset])
1890                 return 0;
1891
1892         a_mut = bch2_alloc_to_v4_mut(trans, k);
1893         ret = PTR_ERR_OR_ZERO(a_mut);
1894         if (ret)
1895                 return ret;
1896
1897         a_mut->v.oldest_gen = ca->oldest_gen[iter->pos.offset];
1898         a_mut->v.data_type = alloc_data_type(a_mut->v, a_mut->v.data_type);
1899
1900         return bch2_trans_update(trans, iter, &a_mut->k_i, 0);
1901 }
1902
1903 int bch2_gc_gens(struct bch_fs *c)
1904 {
1905         u64 b, start_time = local_clock();
1906         int ret;
1907
1908         /*
1909          * Ideally we would be using state_lock and not gc_lock here, but that
1910          * introduces a deadlock in the RO path - we currently take the state
1911          * lock at the start of going RO, thus the gc thread may get stuck:
1912          */
1913         if (!mutex_trylock(&c->gc_gens_lock))
1914                 return 0;
1915
1916         trace_and_count(c, gc_gens_start, c);
1917         down_read(&c->gc_lock);
1918
1919         for_each_member_device(c, ca) {
1920                 struct bucket_gens *gens = bucket_gens(ca);
1921
1922                 BUG_ON(ca->oldest_gen);
1923
1924                 ca->oldest_gen = kvmalloc(gens->nbuckets, GFP_KERNEL);
1925                 if (!ca->oldest_gen) {
1926                         percpu_ref_put(&ca->ref);
1927                         ret = -BCH_ERR_ENOMEM_gc_gens;
1928                         goto err;
1929                 }
1930
1931                 for (b = gens->first_bucket;
1932                      b < gens->nbuckets; b++)
1933                         ca->oldest_gen[b] = gens->b[b];
1934         }
1935
1936         for (unsigned i = 0; i < BTREE_ID_NR; i++)
1937                 if (btree_type_has_ptrs(i)) {
1938                         c->gc_gens_btree = i;
1939                         c->gc_gens_pos = POS_MIN;
1940
1941                         ret = bch2_trans_run(c,
1942                                 for_each_btree_key_commit(trans, iter, i,
1943                                                 POS_MIN,
1944                                                 BTREE_ITER_PREFETCH|BTREE_ITER_ALL_SNAPSHOTS,
1945                                                 k,
1946                                                 NULL, NULL,
1947                                                 BCH_TRANS_COMMIT_no_enospc,
1948                                         gc_btree_gens_key(trans, &iter, k)));
1949                         if (ret)
1950                                 goto err;
1951                 }
1952
1953         ret = bch2_trans_run(c,
1954                 for_each_btree_key_commit(trans, iter, BTREE_ID_alloc,
1955                                 POS_MIN,
1956                                 BTREE_ITER_PREFETCH,
1957                                 k,
1958                                 NULL, NULL,
1959                                 BCH_TRANS_COMMIT_no_enospc,
1960                         bch2_alloc_write_oldest_gen(trans, &iter, k)));
1961         if (ret)
1962                 goto err;
1963
1964         c->gc_gens_btree        = 0;
1965         c->gc_gens_pos          = POS_MIN;
1966
1967         c->gc_count++;
1968
1969         bch2_time_stats_update(&c->times[BCH_TIME_btree_gc], start_time);
1970         trace_and_count(c, gc_gens_end, c);
1971 err:
1972         for_each_member_device(c, ca) {
1973                 kvfree(ca->oldest_gen);
1974                 ca->oldest_gen = NULL;
1975         }
1976
1977         up_read(&c->gc_lock);
1978         mutex_unlock(&c->gc_gens_lock);
1979         if (!bch2_err_matches(ret, EROFS))
1980                 bch_err_fn(c, ret);
1981         return ret;
1982 }
1983
1984 static int bch2_gc_thread(void *arg)
1985 {
1986         struct bch_fs *c = arg;
1987         struct io_clock *clock = &c->io_clock[WRITE];
1988         unsigned long last = atomic64_read(&clock->now);
1989         unsigned last_kick = atomic_read(&c->kick_gc);
1990         int ret;
1991
1992         set_freezable();
1993
1994         while (1) {
1995                 while (1) {
1996                         set_current_state(TASK_INTERRUPTIBLE);
1997
1998                         if (kthread_should_stop()) {
1999                                 __set_current_state(TASK_RUNNING);
2000                                 return 0;
2001                         }
2002
2003                         if (atomic_read(&c->kick_gc) != last_kick)
2004                                 break;
2005
2006                         if (c->btree_gc_periodic) {
2007                                 unsigned long next = last + c->capacity / 16;
2008
2009                                 if (atomic64_read(&clock->now) >= next)
2010                                         break;
2011
2012                                 bch2_io_clock_schedule_timeout(clock, next);
2013                         } else {
2014                                 schedule();
2015                         }
2016
2017                         try_to_freeze();
2018                 }
2019                 __set_current_state(TASK_RUNNING);
2020
2021                 last = atomic64_read(&clock->now);
2022                 last_kick = atomic_read(&c->kick_gc);
2023
2024                 /*
2025                  * Full gc is currently incompatible with btree key cache:
2026                  */
2027 #if 0
2028                 ret = bch2_gc(c, false, false);
2029 #else
2030                 ret = bch2_gc_gens(c);
2031 #endif
2032                 debug_check_no_locks_held();
2033         }
2034
2035         return 0;
2036 }
2037
2038 void bch2_gc_thread_stop(struct bch_fs *c)
2039 {
2040         struct task_struct *p;
2041
2042         p = c->gc_thread;
2043         c->gc_thread = NULL;
2044
2045         if (p) {
2046                 kthread_stop(p);
2047                 put_task_struct(p);
2048         }
2049 }
2050
2051 int bch2_gc_thread_start(struct bch_fs *c)
2052 {
2053         struct task_struct *p;
2054
2055         if (c->gc_thread)
2056                 return 0;
2057
2058         p = kthread_create(bch2_gc_thread, c, "bch-gc/%s", c->name);
2059         if (IS_ERR(p)) {
2060                 bch_err_fn(c, PTR_ERR(p));
2061                 return PTR_ERR(p);
2062         }
2063
2064         get_task_struct(p);
2065         c->gc_thread = p;
2066         wake_up_process(p);
2067         return 0;
2068 }