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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Assorted bcachefs debug code
   4  *
   5  * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
   6  * Copyright 2012 Google, Inc.
   7  */
   8
   9 #include "bcachefs.h"
  10 #include "bkey_methods.h"
  11 #include "btree_cache.h"
  12 #include "btree_io.h"
  13 #include "btree_iter.h"
  14 #include "btree_locking.h"
  15 #include "btree_update.h"
  16 #include "buckets.h"
  17 #include "debug.h"
  18 #include "error.h"
  19 #include "extents.h"
  20 #include "fsck.h"
  21 #include "inode.h"
  22 #include "io.h"
  23 #include "super.h"
  24
  25 #include <linux/console.h>
  26 #include <linux/debugfs.h>
  27 #include <linux/module.h>
  28 #include <linux/pretty-printers.h>
  29 #include <linux/random.h>
  30 #include <linux/seq_file.h>
  31
  32 static struct dentry *bch_debug;
  33
  34 static bool bch2_btree_verify_replica(struct bch_fs *c, struct btree *b,
  35                                       struct extent_ptr_decoded pick)
  36 {
  37         struct btree *v = c->verify_data;
  38         struct btree_node *n_ondisk = c->verify_ondisk;
  39         struct btree_node *n_sorted = c->verify_data->data;
  40         struct bset *sorted, *inmemory = &b->data->keys;
  41         struct bch_dev *ca = bch_dev_bkey_exists(c, pick.ptr.dev);
  42         struct bio *bio;
  43         bool failed = false;
  44
  45         if (!bch2_dev_get_ioref(ca, READ))
  46                 return false;
  47
  48         bio = bio_alloc_bioset(ca->disk_sb.bdev,
  49                                buf_pages(n_sorted, btree_bytes(c)),
  50                                REQ_OP_READ|REQ_META,
  51                                GFP_NOIO,
  52                                &c->btree_bio);
  53         bio->bi_iter.bi_sector  = pick.ptr.offset;
  54         bch2_bio_map(bio, n_sorted, btree_bytes(c));
  55
  56         submit_bio_wait(bio);
  57
  58         bio_put(bio);
  59         percpu_ref_put(&ca->io_ref);
  60
  61         memcpy(n_ondisk, n_sorted, btree_bytes(c));
  62
  63         v->written = 0;
  64         if (bch2_btree_node_read_done(c, ca, v, false))
  65                 return false;
  66
  67         n_sorted = c->verify_data->data;
  68         sorted = &n_sorted->keys;
  69
  70         if (inmemory->u64s != sorted->u64s ||
  71             memcmp(inmemory->start,
  72                    sorted->start,
  73                    vstruct_end(inmemory) - (void *) inmemory->start)) {
  74                 unsigned offset = 0, sectors;
  75                 struct bset *i;
  76                 unsigned j;
  77
  78                 console_lock();
  79
  80                 printk(KERN_ERR "*** in memory:\n");
  81                 bch2_dump_bset(c, b, inmemory, 0);
  82
  83                 printk(KERN_ERR "*** read back in:\n");
  84                 bch2_dump_bset(c, v, sorted, 0);
  85
  86                 while (offset < v->written) {
  87                         if (!offset) {
  88                                 i = &n_ondisk->keys;
  89                                 sectors = vstruct_blocks(n_ondisk, c->block_bits) <<
  90                                         c->block_bits;
  91                         } else {
  92                                 struct btree_node_entry *bne =
  93                                         (void *) n_ondisk + (offset << 9);
  94                                 i = &bne->keys;
  95
  96                                 sectors = vstruct_blocks(bne, c->block_bits) <<
  97                                         c->block_bits;
  98                         }
  99
 100                         printk(KERN_ERR "*** on disk block %u:\n", offset);
 101                         bch2_dump_bset(c, b, i, offset);
 102
 103                         offset += sectors;
 104                 }
 105
 106                 for (j = 0; j < le16_to_cpu(inmemory->u64s); j++)
 107                         if (inmemory->_data[j] != sorted->_data[j])
 108                                 break;
 109
 110                 console_unlock();
 111                 bch_err(c, "verify failed at key %u", j);
 112
 113                 failed = true;
 114         }
 115
 116         if (v->written != b->written) {
 117                 bch_err(c, "written wrong: expected %u, got %u",
 118                         b->written, v->written);
 119                 failed = true;
 120         }
 121
 122         return failed;
 123 }
 124
 125 void __bch2_btree_verify(struct bch_fs *c, struct btree *b)
 126 {
 127         struct bkey_ptrs_c ptrs;
 128         struct extent_ptr_decoded p;
 129         const union bch_extent_entry *entry;
 130         struct btree *v;
 131         struct bset *inmemory = &b->data->keys;
 132         struct bkey_packed *k;
 133         bool failed = false;
 134
 135         if (c->opts.nochanges)
 136                 return;
 137
 138         bch2_btree_node_io_lock(b);
 139         mutex_lock(&c->verify_lock);
 140
 141         if (!c->verify_ondisk) {
 142                 c->verify_ondisk = kvpmalloc(btree_bytes(c), GFP_KERNEL);
 143                 if (!c->verify_ondisk)
 144                         goto out;
 145         }
 146
 147         if (!c->verify_data) {
 148                 c->verify_data = __bch2_btree_node_mem_alloc(c);
 149                 if (!c->verify_data)
 150                         goto out;
 151
 152                 list_del_init(&c->verify_data->list);
 153         }
 154
 155         BUG_ON(b->nsets != 1);
 156
 157         for (k = inmemory->start; k != vstruct_last(inmemory); k = bkey_next(k))
 158                 if (k->type == KEY_TYPE_btree_ptr_v2) {
 159                         struct bch_btree_ptr_v2 *v = (void *) bkeyp_val(&b->format, k);
 160                         v->mem_ptr = 0;
 161                 }
 162
 163         v = c->verify_data;
 164         bkey_copy(&v->key, &b->key);
 165         v->c.level      = b->c.level;
 166         v->c.btree_id   = b->c.btree_id;
 167         bch2_btree_keys_init(v);
 168
 169         ptrs = bch2_bkey_ptrs_c(bkey_i_to_s_c(&b->key));
 170         bkey_for_each_ptr_decode(&b->key.k, ptrs, p, entry)
 171                 failed |= bch2_btree_verify_replica(c, b, p);
 172
 173         if (failed) {
 174                 struct printbuf buf = PRINTBUF;
 175
 176                 bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&b->key));
 177                 bch2_fs_fatal_error(c, "btree node verify failed for : %s\n", buf.buf);
 178                 printbuf_exit(&buf);
 179         }
 180 out:
 181         mutex_unlock(&c->verify_lock);
 182         bch2_btree_node_io_unlock(b);
 183 }
 184
 185 #ifdef CONFIG_DEBUG_FS
 186
 187 /* XXX: bch_fs refcounting */
 188
 189 struct dump_iter {
 190         struct bch_fs           *c;
 191         enum btree_id           id;
 192         struct bpos             from;
 193         struct bpos             prev_node;
 194         u64                     iter;
 195
 196         struct printbuf         buf;
 197
 198         char __user             *ubuf;  /* destination user buffer */
 199         size_t                  size;   /* size of requested read */
 200         ssize_t                 ret;    /* bytes read so far */
 201 };
 202
 203 static ssize_t flush_buf(struct dump_iter *i)
 204 {
 205         if (i->buf.pos) {
 206                 size_t bytes = min_t(size_t, i->buf.pos, i->size);
 207                 int err = copy_to_user(i->ubuf, i->buf.buf, bytes);
 208
 209                 if (err)
 210                         return err;
 211
 212                 i->ret   += bytes;
 213                 i->ubuf  += bytes;
 214                 i->size  -= bytes;
 215                 i->buf.pos -= bytes;
 216                 memmove(i->buf.buf, i->buf.buf + bytes, i->buf.pos);
 217         }
 218
 219         return i->size ? 0 : i->ret;
 220 }
 221
 222 static int bch2_dump_open(struct inode *inode, struct file *file)
 223 {
 224         struct btree_debug *bd = inode->i_private;
 225         struct dump_iter *i;
 226
 227         i = kzalloc(sizeof(struct dump_iter), GFP_KERNEL);
 228         if (!i)
 229                 return -ENOMEM;
 230
 231         file->private_data = i;
 232         i->from = POS_MIN;
 233         i->iter = 0;
 234         i->c    = container_of(bd, struct bch_fs, btree_debug[bd->id]);
 235         i->id   = bd->id;
 236         i->buf  = PRINTBUF;
 237
 238         return 0;
 239 }
 240
 241 static int bch2_dump_release(struct inode *inode, struct file *file)
 242 {
 243         struct dump_iter *i = file->private_data;
 244
 245         printbuf_exit(&i->buf);
 246         kfree(i);
 247         return 0;
 248 }
 249
 250 static ssize_t bch2_read_btree(struct file *file, char __user *buf,
 251                                size_t size, loff_t *ppos)
 252 {
 253         struct dump_iter *i = file->private_data;
 254         struct btree_trans trans;
 255         struct btree_iter iter;
 256         struct bkey_s_c k;
 257         ssize_t ret;
 258
 259         i->ubuf = buf;
 260         i->size = size;
 261         i->ret  = 0;
 262
 263         bch2_trans_init(&trans, i->c, 0, 0);
 264
 265         ret = for_each_btree_key2(&trans, iter, i->id, i->from,
 266                                   BTREE_ITER_PREFETCH|
 267                                   BTREE_ITER_ALL_SNAPSHOTS, k, ({
 268                 ret = flush_buf(i);
 269                 if (ret)
 270                         break;
 271
 272                 bch2_bkey_val_to_text(&i->buf, i->c, k);
 273                 prt_newline(&i->buf);
 274                 0;
 275         }));
 276         i->from = iter.pos;
 277
 278         if (!ret)
 279                 ret = flush_buf(i);
 280
 281         bch2_trans_exit(&trans);
 282
 283         return ret ?: i->ret;
 284 }
 285
 286 static const struct file_operations btree_debug_ops = {
 287         .owner          = THIS_MODULE,
 288         .open           = bch2_dump_open,
 289         .release        = bch2_dump_release,
 290         .read           = bch2_read_btree,
 291 };
 292
 293 static ssize_t bch2_read_btree_formats(struct file *file, char __user *buf,
 294                                        size_t size, loff_t *ppos)
 295 {
 296         struct dump_iter *i = file->private_data;
 297         struct btree_trans trans;
 298         struct btree_iter iter;
 299         struct btree *b;
 300         ssize_t ret;
 301
 302         i->ubuf = buf;
 303         i->size = size;
 304         i->ret  = 0;
 305
 306         ret = flush_buf(i);
 307         if (ret)
 308                 return ret;
 309
 310         if (!bpos_cmp(SPOS_MAX, i->from))
 311                 return i->ret;
 312
 313         bch2_trans_init(&trans, i->c, 0, 0);
 314
 315         for_each_btree_node(&trans, iter, i->id, i->from, 0, b, ret) {
 316                 ret = flush_buf(i);
 317                 if (ret)
 318                         break;
 319
 320                 bch2_btree_node_to_text(&i->buf, i->c, b);
 321                 i->from = bpos_cmp(SPOS_MAX, b->key.k.p)
 322                         ? bpos_successor(b->key.k.p)
 323                         : b->key.k.p;
 324         }
 325         bch2_trans_iter_exit(&trans, &iter);
 326
 327         bch2_trans_exit(&trans);
 328
 329         if (!ret)
 330                 ret = flush_buf(i);
 331
 332         return ret ?: i->ret;
 333 }
 334
 335 static const struct file_operations btree_format_debug_ops = {
 336         .owner          = THIS_MODULE,
 337         .open           = bch2_dump_open,
 338         .release        = bch2_dump_release,
 339         .read           = bch2_read_btree_formats,
 340 };
 341
 342 static ssize_t bch2_read_bfloat_failed(struct file *file, char __user *buf,
 343                                        size_t size, loff_t *ppos)
 344 {
 345         struct dump_iter *i = file->private_data;
 346         struct btree_trans trans;
 347         struct btree_iter iter;
 348         struct bkey_s_c k;
 349         ssize_t ret;
 350
 351         i->ubuf = buf;
 352         i->size = size;
 353         i->ret  = 0;
 354
 355         ret = flush_buf(i);
 356         if (ret)
 357                 return ret;
 358
 359         bch2_trans_init(&trans, i->c, 0, 0);
 360
 361         ret = for_each_btree_key2(&trans, iter, i->id, i->from,
 362                                   BTREE_ITER_PREFETCH|
 363                                   BTREE_ITER_ALL_SNAPSHOTS, k, ({
 364                 struct btree_path_level *l = &iter.path->l[0];
 365                 struct bkey_packed *_k =
 366                         bch2_btree_node_iter_peek(&l->iter, l->b);
 367
 368                 ret = flush_buf(i);
 369                 if (ret)
 370                         break;
 371
 372                 if (bpos_cmp(l->b->key.k.p, i->prev_node) > 0) {
 373                         bch2_btree_node_to_text(&i->buf, i->c, l->b);
 374                         i->prev_node = l->b->key.k.p;
 375                 }
 376
 377                 bch2_bfloat_to_text(&i->buf, l->b, _k);
 378                 0;
 379         }));
 380         i->from = iter.pos;
 381
 382         bch2_trans_exit(&trans);
 383
 384         if (!ret)
 385                 ret = flush_buf(i);
 386
 387         return ret ?: i->ret;
 388 }
 389
 390 static const struct file_operations bfloat_failed_debug_ops = {
 391         .owner          = THIS_MODULE,
 392         .open           = bch2_dump_open,
 393         .release        = bch2_dump_release,
 394         .read           = bch2_read_bfloat_failed,
 395 };
 396
 397 static void bch2_cached_btree_node_to_text(struct printbuf *out, struct bch_fs *c,
 398                                            struct btree *b)
 399 {
 400         if (!out->nr_tabstops)
 401                 printbuf_tabstop_push(out, 32);
 402
 403         prt_printf(out, "%px btree=%s l=%u ",
 404                b,
 405                bch2_btree_ids[b->c.btree_id],
 406                b->c.level);
 407         prt_newline(out);
 408
 409         printbuf_indent_add(out, 2);
 410
 411         bch2_bkey_val_to_text(out, c, bkey_i_to_s_c(&b->key));
 412         prt_newline(out);
 413
 414         prt_printf(out, "flags: ");
 415         prt_tab(out);
 416         prt_bitflags(out, bch2_btree_node_flags, b->flags);
 417         prt_newline(out);
 418
 419         prt_printf(out, "pcpu read locks: ");
 420         prt_tab(out);
 421         prt_printf(out, "%u", b->c.lock.readers != NULL);
 422         prt_newline(out);
 423
 424         prt_printf(out, "written:");
 425         prt_tab(out);
 426         prt_printf(out, "%u", b->written);
 427         prt_newline(out);
 428
 429         prt_printf(out, "writes blocked:");
 430         prt_tab(out);
 431         prt_printf(out, "%u", !list_empty_careful(&b->write_blocked));
 432         prt_newline(out);
 433
 434         prt_printf(out, "will make reachable:");
 435         prt_tab(out);
 436         prt_printf(out, "%lx", b->will_make_reachable);
 437         prt_newline(out);
 438
 439         prt_printf(out, "journal pin %px:", &b->writes[0].journal);
 440         prt_tab(out);
 441         prt_printf(out, "%llu", b->writes[0].journal.seq);
 442         prt_newline(out);
 443
 444         prt_printf(out, "journal pin %px:", &b->writes[1].journal);
 445         prt_tab(out);
 446         prt_printf(out, "%llu", b->writes[1].journal.seq);
 447         prt_newline(out);
 448
 449         printbuf_indent_sub(out, 2);
 450 }
 451
 452 static ssize_t bch2_cached_btree_nodes_read(struct file *file, char __user *buf,
 453                                             size_t size, loff_t *ppos)
 454 {
 455         struct dump_iter *i = file->private_data;
 456         struct bch_fs *c = i->c;
 457         bool done = false;
 458         ssize_t ret = 0;
 459
 460         i->ubuf = buf;
 461         i->size = size;
 462         i->ret  = 0;
 463
 464         do {
 465                 struct bucket_table *tbl;
 466                 struct rhash_head *pos;
 467                 struct btree *b;
 468
 469                 ret = flush_buf(i);
 470                 if (ret)
 471                         return ret;
 472
 473                 rcu_read_lock();
 474                 i->buf.atomic++;
 475                 tbl = rht_dereference_rcu(c->btree_cache.table.tbl,
 476                                           &c->btree_cache.table);
 477                 if (i->iter < tbl->size) {
 478                         rht_for_each_entry_rcu(b, pos, tbl, i->iter, hash)
 479                                 bch2_cached_btree_node_to_text(&i->buf, c, b);
 480                         i->iter++;;
 481                 } else {
 482                         done = true;
 483                 }
 484                 --i->buf.atomic;
 485                 rcu_read_unlock();
 486         } while (!done);
 487
 488         if (i->buf.allocation_failure)
 489                 ret = -ENOMEM;
 490
 491         if (!ret)
 492                 ret = flush_buf(i);
 493
 494         return ret ?: i->ret;
 495 }
 496
 497 static const struct file_operations cached_btree_nodes_ops = {
 498         .owner          = THIS_MODULE,
 499         .open           = bch2_dump_open,
 500         .release        = bch2_dump_release,
 501         .read           = bch2_cached_btree_nodes_read,
 502 };
 503
 504 static int prt_backtrace(struct printbuf *out, struct task_struct *task)
 505 {
 506         unsigned long entries[32];
 507         unsigned i, nr_entries;
 508         int ret;
 509
 510         ret = down_read_killable(&task->signal->exec_update_lock);
 511         if (ret)
 512                 return ret;
 513
 514         nr_entries = stack_trace_save_tsk(task, entries, ARRAY_SIZE(entries), 0);
 515         for (i = 0; i < nr_entries; i++) {
 516                 prt_printf(out, "[<0>] %pB", (void *)entries[i]);
 517                 prt_newline(out);
 518         }
 519
 520         up_read(&task->signal->exec_update_lock);
 521         return 0;
 522 }
 523
 524 static ssize_t bch2_btree_transactions_read(struct file *file, char __user *buf,
 525                                             size_t size, loff_t *ppos)
 526 {
 527         struct dump_iter *i = file->private_data;
 528         struct bch_fs *c = i->c;
 529         struct btree_trans *trans;
 530         ssize_t ret = 0;
 531
 532         i->ubuf = buf;
 533         i->size = size;
 534         i->ret  = 0;
 535
 536         mutex_lock(&c->btree_trans_lock);
 537         list_for_each_entry(trans, &c->btree_trans_list, list) {
 538                 if (trans->locking_wait.task->pid <= i->iter)
 539                         continue;
 540
 541                 ret = flush_buf(i);
 542                 if (ret)
 543                         return ret;
 544
 545                 bch2_btree_trans_to_text(&i->buf, trans);
 546
 547                 prt_printf(&i->buf, "backtrace:");
 548                 prt_newline(&i->buf);
 549                 printbuf_indent_add(&i->buf, 2);
 550                 prt_backtrace(&i->buf, trans->locking_wait.task);
 551                 printbuf_indent_sub(&i->buf, 2);
 552                 prt_newline(&i->buf);
 553
 554                 i->iter = trans->locking_wait.task->pid;
 555         }
 556         mutex_unlock(&c->btree_trans_lock);
 557
 558         if (i->buf.allocation_failure)
 559                 ret = -ENOMEM;
 560
 561         if (!ret)
 562                 ret = flush_buf(i);
 563
 564         return ret ?: i->ret;
 565 }
 566
 567 static const struct file_operations btree_transactions_ops = {
 568         .owner          = THIS_MODULE,
 569         .open           = bch2_dump_open,
 570         .release        = bch2_dump_release,
 571         .read           = bch2_btree_transactions_read,
 572 };
 573
 574 static ssize_t bch2_journal_pins_read(struct file *file, char __user *buf,
 575                                       size_t size, loff_t *ppos)
 576 {
 577         struct dump_iter *i = file->private_data;
 578         struct bch_fs *c = i->c;
 579         bool done = false;
 580         int err;
 581
 582         i->ubuf = buf;
 583         i->size = size;
 584         i->ret  = 0;
 585
 586         do {
 587                 err = flush_buf(i);
 588                 if (err)
 589                         return err;
 590
 591                 if (!i->size)
 592                         break;
 593
 594                 done = bch2_journal_seq_pins_to_text(&i->buf, &c->journal, &i->iter);
 595                 i->iter++;
 596         } while (!done);
 597
 598         if (i->buf.allocation_failure)
 599                 return -ENOMEM;
 600
 601         return i->ret;
 602 }
 603
 604 static const struct file_operations journal_pins_ops = {
 605         .owner          = THIS_MODULE,
 606         .open           = bch2_dump_open,
 607         .release        = bch2_dump_release,
 608         .read           = bch2_journal_pins_read,
 609 };
 610
 611 static int lock_held_stats_open(struct inode *inode, struct file *file)
 612 {
 613         struct bch_fs *c = inode->i_private;
 614         struct dump_iter *i;
 615
 616         i = kzalloc(sizeof(struct dump_iter), GFP_KERNEL);
 617
 618         if (!i)
 619                 return -ENOMEM;
 620
 621         i->iter = 0;
 622         i->c    = c;
 623         i->buf  = PRINTBUF;
 624         file->private_data = i;
 625
 626         return 0;
 627 }
 628
 629 static int lock_held_stats_release(struct inode *inode, struct file *file)
 630 {
 631         struct dump_iter *i = file->private_data;
 632
 633         printbuf_exit(&i->buf);
 634         kfree(i);
 635
 636         return 0;
 637 }
 638
 639 static ssize_t lock_held_stats_read(struct file *file, char __user *buf,
 640                                       size_t size, loff_t *ppos)
 641 {
 642         struct dump_iter        *i = file->private_data;
 643         struct bch_fs *c = i->c;
 644         int err;
 645
 646         i->ubuf = buf;
 647         i->size = size;
 648         i->ret  = 0;
 649
 650         while (1) {
 651                 struct btree_transaction_stats *s = &c->btree_transaction_stats[i->iter];
 652
 653                 err = flush_buf(i);
 654                 if (err)
 655                         return err;
 656
 657                 if (!i->size)
 658                         break;
 659
 660                 if (i->iter == ARRAY_SIZE(c->btree_transaction_fns) ||
 661                     !c->btree_transaction_fns[i->iter])
 662                         break;
 663
 664                 prt_printf(&i->buf, "%s: ", c->btree_transaction_fns[i->iter]);
 665                 prt_newline(&i->buf);
 666                 printbuf_indent_add(&i->buf, 2);
 667
 668                 mutex_lock(&s->lock);
 669
 670                 prt_printf(&i->buf, "Max mem used: %u", s->max_mem);
 671                 prt_newline(&i->buf);
 672
 673                 if (IS_ENABLED(CONFIG_BCACHEFS_LOCK_TIME_STATS)) {
 674                         prt_printf(&i->buf, "Lock hold times:");
 675                         prt_newline(&i->buf);
 676
 677                         printbuf_indent_add(&i->buf, 2);
 678                         bch2_time_stats_to_text(&i->buf, &s->lock_hold_times);
 679                         printbuf_indent_sub(&i->buf, 2);
 680                 }
 681
 682                 if (s->max_paths_text) {
 683                         prt_printf(&i->buf, "Maximum allocated btree paths (%u):", s->nr_max_paths);
 684                         prt_newline(&i->buf);
 685
 686                         printbuf_indent_add(&i->buf, 2);
 687                         prt_str_indented(&i->buf, s->max_paths_text);
 688                         printbuf_indent_sub(&i->buf, 2);
 689                 }
 690
 691                 mutex_unlock(&s->lock);
 692
 693                 printbuf_indent_sub(&i->buf, 2);
 694                 prt_newline(&i->buf);
 695                 i->iter++;
 696         }
 697
 698         if (i->buf.allocation_failure)
 699                 return -ENOMEM;
 700
 701         return i->ret;
 702 }
 703
 704 static const struct file_operations lock_held_stats_op = {
 705         .owner = THIS_MODULE,
 706         .open = lock_held_stats_open,
 707         .release = lock_held_stats_release,
 708         .read = lock_held_stats_read,
 709 };
 710
 711 static ssize_t bch2_btree_deadlock_read(struct file *file, char __user *buf,
 712                                             size_t size, loff_t *ppos)
 713 {
 714         struct dump_iter *i = file->private_data;
 715         struct bch_fs *c = i->c;
 716         struct btree_trans *trans;
 717         ssize_t ret = 0;
 718
 719         i->ubuf = buf;
 720         i->size = size;
 721         i->ret  = 0;
 722
 723         if (i->iter)
 724                 goto out;
 725
 726         mutex_lock(&c->btree_trans_lock);
 727         list_for_each_entry(trans, &c->btree_trans_list, list)
 728                 if (bch2_check_for_deadlock(trans, &i->buf)) {
 729                         i->iter = 1;
 730                         break;
 731                 }
 732         mutex_unlock(&c->btree_trans_lock);
 733 out:
 734         if (i->buf.allocation_failure)
 735                 ret = -ENOMEM;
 736
 737         if (!ret)
 738                 ret = flush_buf(i);
 739
 740         return ret ?: i->ret;
 741 }
 742
 743 static const struct file_operations btree_deadlock_ops = {
 744         .owner          = THIS_MODULE,
 745         .open           = bch2_dump_open,
 746         .release        = bch2_dump_release,
 747         .read           = bch2_btree_deadlock_read,
 748 };
 749
 750 void bch2_fs_debug_exit(struct bch_fs *c)
 751 {
 752         if (!IS_ERR_OR_NULL(c->fs_debug_dir))
 753                 debugfs_remove_recursive(c->fs_debug_dir);
 754 }
 755
 756 void bch2_fs_debug_init(struct bch_fs *c)
 757 {
 758         struct btree_debug *bd;
 759         char name[100];
 760
 761         if (IS_ERR_OR_NULL(bch_debug))
 762                 return;
 763
 764         snprintf(name, sizeof(name), "%pU", c->sb.user_uuid.b);
 765         c->fs_debug_dir = debugfs_create_dir(name, bch_debug);
 766         if (IS_ERR_OR_NULL(c->fs_debug_dir))
 767                 return;
 768
 769         debugfs_create_file("cached_btree_nodes", 0400, c->fs_debug_dir,
 770                             c->btree_debug, &cached_btree_nodes_ops);
 771
 772         debugfs_create_file("btree_transactions", 0400, c->fs_debug_dir,
 773                             c->btree_debug, &btree_transactions_ops);
 774
 775         debugfs_create_file("journal_pins", 0400, c->fs_debug_dir,
 776                             c->btree_debug, &journal_pins_ops);
 777
 778         debugfs_create_file("btree_transaction_stats", 0400, c->fs_debug_dir,
 779                             c, &lock_held_stats_op);
 780
 781         debugfs_create_file("btree_deadlock", 0400, c->fs_debug_dir,
 782                             c->btree_debug, &btree_deadlock_ops);
 783
 784         c->btree_debug_dir = debugfs_create_dir("btrees", c->fs_debug_dir);
 785         if (IS_ERR_OR_NULL(c->btree_debug_dir))
 786                 return;
 787
 788         for (bd = c->btree_debug;
 789              bd < c->btree_debug + ARRAY_SIZE(c->btree_debug);
 790              bd++) {
 791                 bd->id = bd - c->btree_debug;
 792                 debugfs_create_file(bch2_btree_ids[bd->id],
 793                                     0400, c->btree_debug_dir, bd,
 794                                     &btree_debug_ops);
 795
 796                 snprintf(name, sizeof(name), "%s-formats",
 797                          bch2_btree_ids[bd->id]);
 798
 799                 debugfs_create_file(name, 0400, c->btree_debug_dir, bd,
 800                                     &btree_format_debug_ops);
 801
 802                 snprintf(name, sizeof(name), "%s-bfloat-failed",
 803                          bch2_btree_ids[bd->id]);
 804
 805                 debugfs_create_file(name, 0400, c->btree_debug_dir, bd,
 806                                     &bfloat_failed_debug_ops);
 807         }
 808 }
 809
 810 #endif
 811
 812 void bch2_debug_exit(void)
 813 {
 814         if (!IS_ERR_OR_NULL(bch_debug))
 815                 debugfs_remove_recursive(bch_debug);
 816 }
 817
 818 int __init bch2_debug_init(void)
 819 {
 820         int ret = 0;
 821
 822         bch_debug = debugfs_create_dir("bcachefs", NULL);
 823         return ret;
 824 }