fs/btrfs/scrub.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2011, 2012 STRATO.  All rights reserved.
   4  */
   5
   6 #include <linux/blkdev.h>
   7 #include <linux/ratelimit.h>
   8 #include <linux/sched/mm.h>
   9 #include <crypto/hash.h>
  10 #include "ctree.h"
  11 #include "discard.h"
  12 #include "volumes.h"
  13 #include "disk-io.h"
  14 #include "ordered-data.h"
  15 #include "transaction.h"
  16 #include "backref.h"
  17 #include "extent_io.h"
  18 #include "dev-replace.h"
  19 #include "check-integrity.h"
  20 #include "rcu-string.h"
  21 #include "raid56.h"
  22 #include "block-group.h"
  23
  24 /*
  25  * This is only the first step towards a full-features scrub. It reads all
  26  * extent and super block and verifies the checksums. In case a bad checksum
  27  * is found or the extent cannot be read, good data will be written back if
  28  * any can be found.
  29  *
  30  * Future enhancements:
  31  *  - In case an unrepairable extent is encountered, track which files are
  32  *    affected and report them
  33  *  - track and record media errors, throw out bad devices
  34  *  - add a mode to also read unallocated space
  35  */
  36
  37 struct scrub_block;
  38 struct scrub_ctx;
  39
  40 /*
  41  * the following three values only influence the performance.
  42  * The last one configures the number of parallel and outstanding I/O
  43  * operations. The first two values configure an upper limit for the number
  44  * of (dynamically allocated) pages that are added to a bio.
  45  */
  46 #define SCRUB_PAGES_PER_RD_BIO  32      /* 128k per bio */
  47 #define SCRUB_PAGES_PER_WR_BIO  32      /* 128k per bio */
  48 #define SCRUB_BIOS_PER_SCTX     64      /* 8MB per device in flight */
  49
  50 /*
  51  * the following value times PAGE_SIZE needs to be large enough to match the
  52  * largest node/leaf/sector size that shall be supported.
  53  * Values larger than BTRFS_STRIPE_LEN are not supported.
  54  */
  55 #define SCRUB_MAX_PAGES_PER_BLOCK       16      /* 64k per node/leaf/sector */
  56
  57 struct scrub_recover {
  58         refcount_t              refs;
  59         struct btrfs_bio        *bbio;
  60         u64                     map_length;
  61 };
  62
  63 struct scrub_page {
  64         struct scrub_block      *sblock;
  65         struct page             *page;
  66         struct btrfs_device     *dev;
  67         struct list_head        list;
  68         u64                     flags;  /* extent flags */
  69         u64                     generation;
  70         u64                     logical;
  71         u64                     physical;
  72         u64                     physical_for_dev_replace;
  73         atomic_t                refs;
  74         struct {
  75                 unsigned int    mirror_num:8;
  76                 unsigned int    have_csum:1;
  77                 unsigned int    io_error:1;
  78         };
  79         u8                      csum[BTRFS_CSUM_SIZE];
  80
  81         struct scrub_recover    *recover;
  82 };
  83
  84 struct scrub_bio {
  85         int                     index;
  86         struct scrub_ctx        *sctx;
  87         struct btrfs_device     *dev;
  88         struct bio              *bio;
  89         blk_status_t            status;
  90         u64                     logical;
  91         u64                     physical;
  92 #if SCRUB_PAGES_PER_WR_BIO >= SCRUB_PAGES_PER_RD_BIO
  93         struct scrub_page       *pagev[SCRUB_PAGES_PER_WR_BIO];
  94 #else
  95         struct scrub_page       *pagev[SCRUB_PAGES_PER_RD_BIO];
  96 #endif
  97         int                     page_count;
  98         int                     next_free;
  99         struct btrfs_work       work;
 100 };
 101
 102 struct scrub_block {
 103         struct scrub_page       *pagev[SCRUB_MAX_PAGES_PER_BLOCK];
 104         int                     page_count;
 105         atomic_t                outstanding_pages;
 106         refcount_t              refs; /* free mem on transition to zero */
 107         struct scrub_ctx        *sctx;
 108         struct scrub_parity     *sparity;
 109         struct {
 110                 unsigned int    header_error:1;
 111                 unsigned int    checksum_error:1;
 112                 unsigned int    no_io_error_seen:1;
 113                 unsigned int    generation_error:1; /* also sets header_error */
 114
 115                 /* The following is for the data used to check parity */
 116                 /* It is for the data with checksum */
 117                 unsigned int    data_corrected:1;
 118         };
 119         struct btrfs_work       work;
 120 };
 121
 122 /* Used for the chunks with parity stripe such RAID5/6 */
 123 struct scrub_parity {
 124         struct scrub_ctx        *sctx;
 125
 126         struct btrfs_device     *scrub_dev;
 127
 128         u64                     logic_start;
 129
 130         u64                     logic_end;
 131
 132         int                     nsectors;
 133
 134         u64                     stripe_len;
 135
 136         refcount_t              refs;
 137
 138         struct list_head        spages;
 139
 140         /* Work of parity check and repair */
 141         struct btrfs_work       work;
 142
 143         /* Mark the parity blocks which have data */
 144         unsigned long           *dbitmap;
 145
 146         /*
 147          * Mark the parity blocks which have data, but errors happen when
 148          * read data or check data
 149          */
 150         unsigned long           *ebitmap;
 151
 152         unsigned long           bitmap[0];
 153 };
 154
 155 struct scrub_ctx {
 156         struct scrub_bio        *bios[SCRUB_BIOS_PER_SCTX];
 157         struct btrfs_fs_info    *fs_info;
 158         int                     first_free;
 159         int                     curr;
 160         atomic_t                bios_in_flight;
 161         atomic_t                workers_pending;
 162         spinlock_t              list_lock;
 163         wait_queue_head_t       list_wait;
 164         u16                     csum_size;
 165         struct list_head        csum_list;
 166         atomic_t                cancel_req;
 167         int                     readonly;
 168         int                     pages_per_rd_bio;
 169
 170         int                     is_dev_replace;
 171
 172         struct scrub_bio        *wr_curr_bio;
 173         struct mutex            wr_lock;
 174         int                     pages_per_wr_bio; /* <= SCRUB_PAGES_PER_WR_BIO */
 175         struct btrfs_device     *wr_tgtdev;
 176         bool                    flush_all_writes;
 177
 178         /*
 179          * statistics
 180          */
 181         struct btrfs_scrub_progress stat;
 182         spinlock_t              stat_lock;
 183
 184         /*
 185          * Use a ref counter to avoid use-after-free issues. Scrub workers
 186          * decrement bios_in_flight and workers_pending and then do a wakeup
 187          * on the list_wait wait queue. We must ensure the main scrub task
 188          * doesn't free the scrub context before or while the workers are
 189          * doing the wakeup() call.
 190          */
 191         refcount_t              refs;
 192 };
 193
 194 struct scrub_warning {
 195         struct btrfs_path       *path;
 196         u64                     extent_item_size;
 197         const char              *errstr;
 198         u64                     physical;
 199         u64                     logical;
 200         struct btrfs_device     *dev;
 201 };
 202
 203 struct full_stripe_lock {
 204         struct rb_node node;
 205         u64 logical;
 206         u64 refs;
 207         struct mutex mutex;
 208 };
 209
 210 static void scrub_pending_bio_inc(struct scrub_ctx *sctx);
 211 static void scrub_pending_bio_dec(struct scrub_ctx *sctx);
 212 static int scrub_handle_errored_block(struct scrub_block *sblock_to_check);
 213 static int scrub_setup_recheck_block(struct scrub_block *original_sblock,
 214                                      struct scrub_block *sblocks_for_recheck);
 215 static void scrub_recheck_block(struct btrfs_fs_info *fs_info,
 216                                 struct scrub_block *sblock,
 217                                 int retry_failed_mirror);
 218 static void scrub_recheck_block_checksum(struct scrub_block *sblock);
 219 static int scrub_repair_block_from_good_copy(struct scrub_block *sblock_bad,
 220                                              struct scrub_block *sblock_good);
 221 static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
 222                                             struct scrub_block *sblock_good,
 223                                             int page_num, int force_write);
 224 static void scrub_write_block_to_dev_replace(struct scrub_block *sblock);
 225 static int scrub_write_page_to_dev_replace(struct scrub_block *sblock,
 226                                            int page_num);
 227 static int scrub_checksum_data(struct scrub_block *sblock);
 228 static int scrub_checksum_tree_block(struct scrub_block *sblock);
 229 static int scrub_checksum_super(struct scrub_block *sblock);
 230 static void scrub_block_get(struct scrub_block *sblock);
 231 static void scrub_block_put(struct scrub_block *sblock);
 232 static void scrub_page_get(struct scrub_page *spage);
 233 static void scrub_page_put(struct scrub_page *spage);
 234 static void scrub_parity_get(struct scrub_parity *sparity);
 235 static void scrub_parity_put(struct scrub_parity *sparity);
 236 static int scrub_add_page_to_rd_bio(struct scrub_ctx *sctx,
 237                                     struct scrub_page *spage);
 238 static int scrub_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
 239                        u64 physical, struct btrfs_device *dev, u64 flags,
 240                        u64 gen, int mirror_num, u8 *csum, int force,
 241                        u64 physical_for_dev_replace);
 242 static void scrub_bio_end_io(struct bio *bio);
 243 static void scrub_bio_end_io_worker(struct btrfs_work *work);
 244 static void scrub_block_complete(struct scrub_block *sblock);
 245 static void scrub_remap_extent(struct btrfs_fs_info *fs_info,
 246                                u64 extent_logical, u64 extent_len,
 247                                u64 *extent_physical,
 248                                struct btrfs_device **extent_dev,
 249                                int *extent_mirror_num);
 250 static int scrub_add_page_to_wr_bio(struct scrub_ctx *sctx,
 251                                     struct scrub_page *spage);
 252 static void scrub_wr_submit(struct scrub_ctx *sctx);
 253 static void scrub_wr_bio_end_io(struct bio *bio);
 254 static void scrub_wr_bio_end_io_worker(struct btrfs_work *work);
 255 static void __scrub_blocked_if_needed(struct btrfs_fs_info *fs_info);
 256 static void scrub_blocked_if_needed(struct btrfs_fs_info *fs_info);
 257 static void scrub_put_ctx(struct scrub_ctx *sctx);
 258
 259 static inline int scrub_is_page_on_raid56(struct scrub_page *page)
 260 {
 261         return page->recover &&
 262                (page->recover->bbio->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK);
 263 }
 264
 265 static void scrub_pending_bio_inc(struct scrub_ctx *sctx)
 266 {
 267         refcount_inc(&sctx->refs);
 268         atomic_inc(&sctx->bios_in_flight);
 269 }
 270
 271 static void scrub_pending_bio_dec(struct scrub_ctx *sctx)
 272 {
 273         atomic_dec(&sctx->bios_in_flight);
 274         wake_up(&sctx->list_wait);
 275         scrub_put_ctx(sctx);
 276 }
 277
 278 static void __scrub_blocked_if_needed(struct btrfs_fs_info *fs_info)
 279 {
 280         while (atomic_read(&fs_info->scrub_pause_req)) {
 281                 mutex_unlock(&fs_info->scrub_lock);
 282                 wait_event(fs_info->scrub_pause_wait,
 283                    atomic_read(&fs_info->scrub_pause_req) == 0);
 284                 mutex_lock(&fs_info->scrub_lock);
 285         }
 286 }
 287
 288 static void scrub_pause_on(struct btrfs_fs_info *fs_info)
 289 {
 290         atomic_inc(&fs_info->scrubs_paused);
 291         wake_up(&fs_info->scrub_pause_wait);
 292 }
 293
 294 static void scrub_pause_off(struct btrfs_fs_info *fs_info)
 295 {
 296         mutex_lock(&fs_info->scrub_lock);
 297         __scrub_blocked_if_needed(fs_info);
 298         atomic_dec(&fs_info->scrubs_paused);
 299         mutex_unlock(&fs_info->scrub_lock);
 300
 301         wake_up(&fs_info->scrub_pause_wait);
 302 }
 303
 304 static void scrub_blocked_if_needed(struct btrfs_fs_info *fs_info)
 305 {
 306         scrub_pause_on(fs_info);
 307         scrub_pause_off(fs_info);
 308 }
 309
 310 /*
 311  * Insert new full stripe lock into full stripe locks tree
 312  *
 313  * Return pointer to existing or newly inserted full_stripe_lock structure if
 314  * everything works well.
 315  * Return ERR_PTR(-ENOMEM) if we failed to allocate memory
 316  *
 317  * NOTE: caller must hold full_stripe_locks_root->lock before calling this
 318  * function
 319  */
 320 static struct full_stripe_lock *insert_full_stripe_lock(
 321                 struct btrfs_full_stripe_locks_tree *locks_root,
 322                 u64 fstripe_logical)
 323 {
 324         struct rb_node **p;
 325         struct rb_node *parent = NULL;
 326         struct full_stripe_lock *entry;
 327         struct full_stripe_lock *ret;
 328
 329         lockdep_assert_held(&locks_root->lock);
 330
 331         p = &locks_root->root.rb_node;
 332         while (*p) {
 333                 parent = *p;
 334                 entry = rb_entry(parent, struct full_stripe_lock, node);
 335                 if (fstripe_logical < entry->logical) {
 336                         p = &(*p)->rb_left;
 337                 } else if (fstripe_logical > entry->logical) {
 338                         p = &(*p)->rb_right;
 339                 } else {
 340                         entry->refs++;
 341                         return entry;
 342                 }
 343         }
 344
 345         /*
 346          * Insert new lock.
 347          */
 348         ret = kmalloc(sizeof(*ret), GFP_KERNEL);
 349         if (!ret)
 350                 return ERR_PTR(-ENOMEM);
 351         ret->logical = fstripe_logical;
 352         ret->refs = 1;
 353         mutex_init(&ret->mutex);
 354
 355         rb_link_node(&ret->node, parent, p);
 356         rb_insert_color(&ret->node, &locks_root->root);
 357         return ret;
 358 }
 359
 360 /*
 361  * Search for a full stripe lock of a block group
 362  *
 363  * Return pointer to existing full stripe lock if found
 364  * Return NULL if not found
 365  */
 366 static struct full_stripe_lock *search_full_stripe_lock(
 367                 struct btrfs_full_stripe_locks_tree *locks_root,
 368                 u64 fstripe_logical)
 369 {
 370         struct rb_node *node;
 371         struct full_stripe_lock *entry;
 372
 373         lockdep_assert_held(&locks_root->lock);
 374
 375         node = locks_root->root.rb_node;
 376         while (node) {
 377                 entry = rb_entry(node, struct full_stripe_lock, node);
 378                 if (fstripe_logical < entry->logical)
 379                         node = node->rb_left;
 380                 else if (fstripe_logical > entry->logical)
 381                         node = node->rb_right;
 382                 else
 383                         return entry;
 384         }
 385         return NULL;
 386 }
 387
 388 /*
 389  * Helper to get full stripe logical from a normal bytenr.
 390  *
 391  * Caller must ensure @cache is a RAID56 block group.
 392  */
 393 static u64 get_full_stripe_logical(struct btrfs_block_group *cache, u64 bytenr)
 394 {
 395         u64 ret;
 396
 397         /*
 398          * Due to chunk item size limit, full stripe length should not be
 399          * larger than U32_MAX. Just a sanity check here.
 400          */
 401         WARN_ON_ONCE(cache->full_stripe_len >= U32_MAX);
 402
 403         /*
 404          * round_down() can only handle power of 2, while RAID56 full
 405          * stripe length can be 64KiB * n, so we need to manually round down.
 406          */
 407         ret = div64_u64(bytenr - cache->start, cache->full_stripe_len) *
 408                         cache->full_stripe_len + cache->start;
 409         return ret;
 410 }
 411
 412 /*
 413  * Lock a full stripe to avoid concurrency of recovery and read
 414  *
 415  * It's only used for profiles with parities (RAID5/6), for other profiles it
 416  * does nothing.
 417  *
 418  * Return 0 if we locked full stripe covering @bytenr, with a mutex held.
 419  * So caller must call unlock_full_stripe() at the same context.
 420  *
 421  * Return <0 if encounters error.
 422  */
 423 static int lock_full_stripe(struct btrfs_fs_info *fs_info, u64 bytenr,
 424                             bool *locked_ret)
 425 {
 426         struct btrfs_block_group *bg_cache;
 427         struct btrfs_full_stripe_locks_tree *locks_root;
 428         struct full_stripe_lock *existing;
 429         u64 fstripe_start;
 430         int ret = 0;
 431
 432         *locked_ret = false;
 433         bg_cache = btrfs_lookup_block_group(fs_info, bytenr);
 434         if (!bg_cache) {
 435                 ASSERT(0);
 436                 return -ENOENT;
 437         }
 438
 439         /* Profiles not based on parity don't need full stripe lock */
 440         if (!(bg_cache->flags & BTRFS_BLOCK_GROUP_RAID56_MASK))
 441                 goto out;
 442         locks_root = &bg_cache->full_stripe_locks_root;
 443
 444         fstripe_start = get_full_stripe_logical(bg_cache, bytenr);
 445
 446         /* Now insert the full stripe lock */
 447         mutex_lock(&locks_root->lock);
 448         existing = insert_full_stripe_lock(locks_root, fstripe_start);
 449         mutex_unlock(&locks_root->lock);
 450         if (IS_ERR(existing)) {
 451                 ret = PTR_ERR(existing);
 452                 goto out;
 453         }
 454         mutex_lock(&existing->mutex);
 455         *locked_ret = true;
 456 out:
 457         btrfs_put_block_group(bg_cache);
 458         return ret;
 459 }
 460
 461 /*
 462  * Unlock a full stripe.
 463  *
 464  * NOTE: Caller must ensure it's the same context calling corresponding
 465  * lock_full_stripe().
 466  *
 467  * Return 0 if we unlock full stripe without problem.
 468  * Return <0 for error
 469  */
 470 static int unlock_full_stripe(struct btrfs_fs_info *fs_info, u64 bytenr,
 471                               bool locked)
 472 {
 473         struct btrfs_block_group *bg_cache;
 474         struct btrfs_full_stripe_locks_tree *locks_root;
 475         struct full_stripe_lock *fstripe_lock;
 476         u64 fstripe_start;
 477         bool freeit = false;
 478         int ret = 0;
 479
 480         /* If we didn't acquire full stripe lock, no need to continue */
 481         if (!locked)
 482                 return 0;
 483
 484         bg_cache = btrfs_lookup_block_group(fs_info, bytenr);
 485         if (!bg_cache) {
 486                 ASSERT(0);
 487                 return -ENOENT;
 488         }
 489         if (!(bg_cache->flags & BTRFS_BLOCK_GROUP_RAID56_MASK))
 490                 goto out;
 491
 492         locks_root = &bg_cache->full_stripe_locks_root;
 493         fstripe_start = get_full_stripe_logical(bg_cache, bytenr);
 494
 495         mutex_lock(&locks_root->lock);
 496         fstripe_lock = search_full_stripe_lock(locks_root, fstripe_start);
 497         /* Unpaired unlock_full_stripe() detected */
 498         if (!fstripe_lock) {
 499                 WARN_ON(1);
 500                 ret = -ENOENT;
 501                 mutex_unlock(&locks_root->lock);
 502                 goto out;
 503         }
 504
 505         if (fstripe_lock->refs == 0) {
 506                 WARN_ON(1);
 507                 btrfs_warn(fs_info, "full stripe lock at %llu refcount underflow",
 508                         fstripe_lock->logical);
 509         } else {
 510                 fstripe_lock->refs--;
 511         }
 512
 513         if (fstripe_lock->refs == 0) {
 514                 rb_erase(&fstripe_lock->node, &locks_root->root);
 515                 freeit = true;
 516         }
 517         mutex_unlock(&locks_root->lock);
 518
 519         mutex_unlock(&fstripe_lock->mutex);
 520         if (freeit)
 521                 kfree(fstripe_lock);
 522 out:
 523         btrfs_put_block_group(bg_cache);
 524         return ret;
 525 }
 526
 527 static void scrub_free_csums(struct scrub_ctx *sctx)
 528 {
 529         while (!list_empty(&sctx->csum_list)) {
 530                 struct btrfs_ordered_sum *sum;
 531                 sum = list_first_entry(&sctx->csum_list,
 532                                        struct btrfs_ordered_sum, list);
 533                 list_del(&sum->list);
 534                 kfree(sum);
 535         }
 536 }
 537
 538 static noinline_for_stack void scrub_free_ctx(struct scrub_ctx *sctx)
 539 {
 540         int i;
 541
 542         if (!sctx)
 543                 return;
 544
 545         /* this can happen when scrub is cancelled */
 546         if (sctx->curr != -1) {
 547                 struct scrub_bio *sbio = sctx->bios[sctx->curr];
 548
 549                 for (i = 0; i < sbio->page_count; i++) {
 550                         WARN_ON(!sbio->pagev[i]->page);
 551                         scrub_block_put(sbio->pagev[i]->sblock);
 552                 }
 553                 bio_put(sbio->bio);
 554         }
 555
 556         for (i = 0; i < SCRUB_BIOS_PER_SCTX; ++i) {
 557                 struct scrub_bio *sbio = sctx->bios[i];
 558
 559                 if (!sbio)
 560                         break;
 561                 kfree(sbio);
 562         }
 563
 564         kfree(sctx->wr_curr_bio);
 565         scrub_free_csums(sctx);
 566         kfree(sctx);
 567 }
 568
 569 static void scrub_put_ctx(struct scrub_ctx *sctx)
 570 {
 571         if (refcount_dec_and_test(&sctx->refs))
 572                 scrub_free_ctx(sctx);
 573 }
 574
 575 static noinline_for_stack struct scrub_ctx *scrub_setup_ctx(
 576                 struct btrfs_fs_info *fs_info, int is_dev_replace)
 577 {
 578         struct scrub_ctx *sctx;
 579         int             i;
 580
 581         sctx = kzalloc(sizeof(*sctx), GFP_KERNEL);
 582         if (!sctx)
 583                 goto nomem;
 584         refcount_set(&sctx->refs, 1);
 585         sctx->is_dev_replace = is_dev_replace;
 586         sctx->pages_per_rd_bio = SCRUB_PAGES_PER_RD_BIO;
 587         sctx->curr = -1;
 588         sctx->fs_info = fs_info;
 589         INIT_LIST_HEAD(&sctx->csum_list);
 590         for (i = 0; i < SCRUB_BIOS_PER_SCTX; ++i) {
 591                 struct scrub_bio *sbio;
 592
 593                 sbio = kzalloc(sizeof(*sbio), GFP_KERNEL);
 594                 if (!sbio)
 595                         goto nomem;
 596                 sctx->bios[i] = sbio;
 597
 598                 sbio->index = i;
 599                 sbio->sctx = sctx;
 600                 sbio->page_count = 0;
 601                 btrfs_init_work(&sbio->work, scrub_bio_end_io_worker, NULL,
 602                                 NULL);
 603
 604                 if (i != SCRUB_BIOS_PER_SCTX - 1)
 605                         sctx->bios[i]->next_free = i + 1;
 606                 else
 607                         sctx->bios[i]->next_free = -1;
 608         }
 609         sctx->first_free = 0;
 610         atomic_set(&sctx->bios_in_flight, 0);
 611         atomic_set(&sctx->workers_pending, 0);
 612         atomic_set(&sctx->cancel_req, 0);
 613         sctx->csum_size = btrfs_super_csum_size(fs_info->super_copy);
 614
 615         spin_lock_init(&sctx->list_lock);
 616         spin_lock_init(&sctx->stat_lock);
 617         init_waitqueue_head(&sctx->list_wait);
 618
 619         WARN_ON(sctx->wr_curr_bio != NULL);
 620         mutex_init(&sctx->wr_lock);
 621         sctx->wr_curr_bio = NULL;
 622         if (is_dev_replace) {
 623                 WARN_ON(!fs_info->dev_replace.tgtdev);
 624                 sctx->pages_per_wr_bio = SCRUB_PAGES_PER_WR_BIO;
 625                 sctx->wr_tgtdev = fs_info->dev_replace.tgtdev;
 626                 sctx->flush_all_writes = false;
 627         }
 628
 629         return sctx;
 630
 631 nomem:
 632         scrub_free_ctx(sctx);
 633         return ERR_PTR(-ENOMEM);
 634 }
 635
 636 static int scrub_print_warning_inode(u64 inum, u64 offset, u64 root,
 637                                      void *warn_ctx)
 638 {
 639         u64 isize;
 640         u32 nlink;
 641         int ret;
 642         int i;
 643         unsigned nofs_flag;
 644         struct extent_buffer *eb;
 645         struct btrfs_inode_item *inode_item;
 646         struct scrub_warning *swarn = warn_ctx;
 647         struct btrfs_fs_info *fs_info = swarn->dev->fs_info;
 648         struct inode_fs_paths *ipath = NULL;
 649         struct btrfs_root *local_root;
 650         struct btrfs_key root_key;
 651         struct btrfs_key key;
 652
 653         root_key.objectid = root;
 654         root_key.type = BTRFS_ROOT_ITEM_KEY;
 655         root_key.offset = (u64)-1;
 656         local_root = btrfs_read_fs_root_no_name(fs_info, &root_key);
 657         if (IS_ERR(local_root)) {
 658                 ret = PTR_ERR(local_root);
 659                 goto err;
 660         }
 661
 662         /*
 663          * this makes the path point to (inum INODE_ITEM ioff)
 664          */
 665         key.objectid = inum;
 666         key.type = BTRFS_INODE_ITEM_KEY;
 667         key.offset = 0;
 668
 669         ret = btrfs_search_slot(NULL, local_root, &key, swarn->path, 0, 0);
 670         if (ret) {
 671                 btrfs_release_path(swarn->path);
 672                 goto err;
 673         }
 674
 675         eb = swarn->path->nodes[0];
 676         inode_item = btrfs_item_ptr(eb, swarn->path->slots[0],
 677                                         struct btrfs_inode_item);
 678         isize = btrfs_inode_size(eb, inode_item);
 679         nlink = btrfs_inode_nlink(eb, inode_item);
 680         btrfs_release_path(swarn->path);
 681
 682         /*
 683          * init_path might indirectly call vmalloc, or use GFP_KERNEL. Scrub
 684          * uses GFP_NOFS in this context, so we keep it consistent but it does
 685          * not seem to be strictly necessary.
 686          */
 687         nofs_flag = memalloc_nofs_save();
 688         ipath = init_ipath(4096, local_root, swarn->path);
 689         memalloc_nofs_restore(nofs_flag);
 690         if (IS_ERR(ipath)) {
 691                 ret = PTR_ERR(ipath);
 692                 ipath = NULL;
 693                 goto err;
 694         }
 695         ret = paths_from_inode(inum, ipath);
 696
 697         if (ret < 0)
 698                 goto err;
 699
 700         /*
 701          * we deliberately ignore the bit ipath might have been too small to
 702          * hold all of the paths here
 703          */
 704         for (i = 0; i < ipath->fspath->elem_cnt; ++i)
 705                 btrfs_warn_in_rcu(fs_info,
 706 "%s at logical %llu on dev %s, physical %llu, root %llu, inode %llu, offset %llu, length %llu, links %u (path: %s)",
 707                                   swarn->errstr, swarn->logical,
 708                                   rcu_str_deref(swarn->dev->name),
 709                                   swarn->physical,
 710                                   root, inum, offset,
 711                                   min(isize - offset, (u64)PAGE_SIZE), nlink,
 712                                   (char *)(unsigned long)ipath->fspath->val[i]);
 713
 714         free_ipath(ipath);
 715         return 0;
 716
 717 err:
 718         btrfs_warn_in_rcu(fs_info,
 719                           "%s at logical %llu on dev %s, physical %llu, root %llu, inode %llu, offset %llu: path resolving failed with ret=%d",
 720                           swarn->errstr, swarn->logical,
 721                           rcu_str_deref(swarn->dev->name),
 722                           swarn->physical,
 723                           root, inum, offset, ret);
 724
 725         free_ipath(ipath);
 726         return 0;
 727 }
 728
 729 static void scrub_print_warning(const char *errstr, struct scrub_block *sblock)
 730 {
 731         struct btrfs_device *dev;
 732         struct btrfs_fs_info *fs_info;
 733         struct btrfs_path *path;
 734         struct btrfs_key found_key;
 735         struct extent_buffer *eb;
 736         struct btrfs_extent_item *ei;
 737         struct scrub_warning swarn;
 738         unsigned long ptr = 0;
 739         u64 extent_item_pos;
 740         u64 flags = 0;
 741         u64 ref_root;
 742         u32 item_size;
 743         u8 ref_level = 0;
 744         int ret;
 745
 746         WARN_ON(sblock->page_count < 1);
 747         dev = sblock->pagev[0]->dev;
 748         fs_info = sblock->sctx->fs_info;
 749
 750         path = btrfs_alloc_path();
 751         if (!path)
 752                 return;
 753
 754         swarn.physical = sblock->pagev[0]->physical;
 755         swarn.logical = sblock->pagev[0]->logical;
 756         swarn.errstr = errstr;
 757         swarn.dev = NULL;
 758
 759         ret = extent_from_logical(fs_info, swarn.logical, path, &found_key,
 760                                   &flags);
 761         if (ret < 0)
 762                 goto out;
 763
 764         extent_item_pos = swarn.logical - found_key.objectid;
 765         swarn.extent_item_size = found_key.offset;
 766
 767         eb = path->nodes[0];
 768         ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
 769         item_size = btrfs_item_size_nr(eb, path->slots[0]);
 770
 771         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
 772                 do {
 773                         ret = tree_backref_for_extent(&ptr, eb, &found_key, ei,
 774                                                       item_size, &ref_root,
 775                                                       &ref_level);
 776                         btrfs_warn_in_rcu(fs_info,
 777 "%s at logical %llu on dev %s, physical %llu: metadata %s (level %d) in tree %llu",
 778                                 errstr, swarn.logical,
 779                                 rcu_str_deref(dev->name),
 780                                 swarn.physical,
 781                                 ref_level ? "node" : "leaf",
 782                                 ret < 0 ? -1 : ref_level,
 783                                 ret < 0 ? -1 : ref_root);
 784                 } while (ret != 1);
 785                 btrfs_release_path(path);
 786         } else {
 787                 btrfs_release_path(path);
 788                 swarn.path = path;
 789                 swarn.dev = dev;
 790                 iterate_extent_inodes(fs_info, found_key.objectid,
 791                                         extent_item_pos, 1,
 792                                         scrub_print_warning_inode, &swarn, false);
 793         }
 794
 795 out:
 796         btrfs_free_path(path);
 797 }
 798
 799 static inline void scrub_get_recover(struct scrub_recover *recover)
 800 {
 801         refcount_inc(&recover->refs);
 802 }
 803
 804 static inline void scrub_put_recover(struct btrfs_fs_info *fs_info,
 805                                      struct scrub_recover *recover)
 806 {
 807         if (refcount_dec_and_test(&recover->refs)) {
 808                 btrfs_bio_counter_dec(fs_info);
 809                 btrfs_put_bbio(recover->bbio);
 810                 kfree(recover);
 811         }
 812 }
 813
 814 /*
 815  * scrub_handle_errored_block gets called when either verification of the
 816  * pages failed or the bio failed to read, e.g. with EIO. In the latter
 817  * case, this function handles all pages in the bio, even though only one
 818  * may be bad.
 819  * The goal of this function is to repair the errored block by using the
 820  * contents of one of the mirrors.
 821  */
 822 static int scrub_handle_errored_block(struct scrub_block *sblock_to_check)
 823 {
 824         struct scrub_ctx *sctx = sblock_to_check->sctx;
 825         struct btrfs_device *dev;
 826         struct btrfs_fs_info *fs_info;
 827         u64 logical;
 828         unsigned int failed_mirror_index;
 829         unsigned int is_metadata;
 830         unsigned int have_csum;
 831         struct scrub_block *sblocks_for_recheck; /* holds one for each mirror */
 832         struct scrub_block *sblock_bad;
 833         int ret;
 834         int mirror_index;
 835         int page_num;
 836         int success;
 837         bool full_stripe_locked;
 838         unsigned int nofs_flag;
 839         static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
 840                                       DEFAULT_RATELIMIT_BURST);
 841
 842         BUG_ON(sblock_to_check->page_count < 1);
 843         fs_info = sctx->fs_info;
 844         if (sblock_to_check->pagev[0]->flags & BTRFS_EXTENT_FLAG_SUPER) {
 845                 /*
 846                  * if we find an error in a super block, we just report it.
 847                  * They will get written with the next transaction commit
 848                  * anyway
 849                  */
 850                 spin_lock(&sctx->stat_lock);
 851                 ++sctx->stat.super_errors;
 852                 spin_unlock(&sctx->stat_lock);
 853                 return 0;
 854         }
 855         logical = sblock_to_check->pagev[0]->logical;
 856         BUG_ON(sblock_to_check->pagev[0]->mirror_num < 1);
 857         failed_mirror_index = sblock_to_check->pagev[0]->mirror_num - 1;
 858         is_metadata = !(sblock_to_check->pagev[0]->flags &
 859                         BTRFS_EXTENT_FLAG_DATA);
 860         have_csum = sblock_to_check->pagev[0]->have_csum;
 861         dev = sblock_to_check->pagev[0]->dev;
 862
 863         /*
 864          * We must use GFP_NOFS because the scrub task might be waiting for a
 865          * worker task executing this function and in turn a transaction commit
 866          * might be waiting the scrub task to pause (which needs to wait for all
 867          * the worker tasks to complete before pausing).
 868          * We do allocations in the workers through insert_full_stripe_lock()
 869          * and scrub_add_page_to_wr_bio(), which happens down the call chain of
 870          * this function.
 871          */
 872         nofs_flag = memalloc_nofs_save();
 873         /*
 874          * For RAID5/6, race can happen for a different device scrub thread.
 875          * For data corruption, Parity and Data threads will both try
 876          * to recovery the data.
 877          * Race can lead to doubly added csum error, or even unrecoverable
 878          * error.
 879          */
 880         ret = lock_full_stripe(fs_info, logical, &full_stripe_locked);
 881         if (ret < 0) {
 882                 memalloc_nofs_restore(nofs_flag);
 883                 spin_lock(&sctx->stat_lock);
 884                 if (ret == -ENOMEM)
 885                         sctx->stat.malloc_errors++;
 886                 sctx->stat.read_errors++;
 887                 sctx->stat.uncorrectable_errors++;
 888                 spin_unlock(&sctx->stat_lock);
 889                 return ret;
 890         }
 891
 892         /*
 893          * read all mirrors one after the other. This includes to
 894          * re-read the extent or metadata block that failed (that was
 895          * the cause that this fixup code is called) another time,
 896          * page by page this time in order to know which pages
 897          * caused I/O errors and which ones are good (for all mirrors).
 898          * It is the goal to handle the situation when more than one
 899          * mirror contains I/O errors, but the errors do not
 900          * overlap, i.e. the data can be repaired by selecting the
 901          * pages from those mirrors without I/O error on the
 902          * particular pages. One example (with blocks >= 2 * PAGE_SIZE)
 903          * would be that mirror #1 has an I/O error on the first page,
 904          * the second page is good, and mirror #2 has an I/O error on
 905          * the second page, but the first page is good.
 906          * Then the first page of the first mirror can be repaired by
 907          * taking the first page of the second mirror, and the
 908          * second page of the second mirror can be repaired by
 909          * copying the contents of the 2nd page of the 1st mirror.
 910          * One more note: if the pages of one mirror contain I/O
 911          * errors, the checksum cannot be verified. In order to get
 912          * the best data for repairing, the first attempt is to find
 913          * a mirror without I/O errors and with a validated checksum.
 914          * Only if this is not possible, the pages are picked from
 915          * mirrors with I/O errors without considering the checksum.
 916          * If the latter is the case, at the end, the checksum of the
 917          * repaired area is verified in order to correctly maintain
 918          * the statistics.
 919          */
 920
 921         sblocks_for_recheck = kcalloc(BTRFS_MAX_MIRRORS,
 922                                       sizeof(*sblocks_for_recheck), GFP_KERNEL);
 923         if (!sblocks_for_recheck) {
 924                 spin_lock(&sctx->stat_lock);
 925                 sctx->stat.malloc_errors++;
 926                 sctx->stat.read_errors++;
 927                 sctx->stat.uncorrectable_errors++;
 928                 spin_unlock(&sctx->stat_lock);
 929                 btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
 930                 goto out;
 931         }
 932
 933         /* setup the context, map the logical blocks and alloc the pages */
 934         ret = scrub_setup_recheck_block(sblock_to_check, sblocks_for_recheck);
 935         if (ret) {
 936                 spin_lock(&sctx->stat_lock);
 937                 sctx->stat.read_errors++;
 938                 sctx->stat.uncorrectable_errors++;
 939                 spin_unlock(&sctx->stat_lock);
 940                 btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
 941                 goto out;
 942         }
 943         BUG_ON(failed_mirror_index >= BTRFS_MAX_MIRRORS);
 944         sblock_bad = sblocks_for_recheck + failed_mirror_index;
 945
 946         /* build and submit the bios for the failed mirror, check checksums */
 947         scrub_recheck_block(fs_info, sblock_bad, 1);
 948
 949         if (!sblock_bad->header_error && !sblock_bad->checksum_error &&
 950             sblock_bad->no_io_error_seen) {
 951                 /*
 952                  * the error disappeared after reading page by page, or
 953                  * the area was part of a huge bio and other parts of the
 954                  * bio caused I/O errors, or the block layer merged several
 955                  * read requests into one and the error is caused by a
 956                  * different bio (usually one of the two latter cases is
 957                  * the cause)
 958                  */
 959                 spin_lock(&sctx->stat_lock);
 960                 sctx->stat.unverified_errors++;
 961                 sblock_to_check->data_corrected = 1;
 962                 spin_unlock(&sctx->stat_lock);
 963
 964                 if (sctx->is_dev_replace)
 965                         scrub_write_block_to_dev_replace(sblock_bad);
 966                 goto out;
 967         }
 968
 969         if (!sblock_bad->no_io_error_seen) {
 970                 spin_lock(&sctx->stat_lock);
 971                 sctx->stat.read_errors++;
 972                 spin_unlock(&sctx->stat_lock);
 973                 if (__ratelimit(&_rs))
 974                         scrub_print_warning("i/o error", sblock_to_check);
 975                 btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
 976         } else if (sblock_bad->checksum_error) {
 977                 spin_lock(&sctx->stat_lock);
 978                 sctx->stat.csum_errors++;
 979                 spin_unlock(&sctx->stat_lock);
 980                 if (__ratelimit(&_rs))
 981                         scrub_print_warning("checksum error", sblock_to_check);
 982                 btrfs_dev_stat_inc_and_print(dev,
 983                                              BTRFS_DEV_STAT_CORRUPTION_ERRS);
 984         } else if (sblock_bad->header_error) {
 985                 spin_lock(&sctx->stat_lock);
 986                 sctx->stat.verify_errors++;
 987                 spin_unlock(&sctx->stat_lock);
 988                 if (__ratelimit(&_rs))
 989                         scrub_print_warning("checksum/header error",
 990                                             sblock_to_check);
 991                 if (sblock_bad->generation_error)
 992                         btrfs_dev_stat_inc_and_print(dev,
 993                                 BTRFS_DEV_STAT_GENERATION_ERRS);
 994                 else
 995                         btrfs_dev_stat_inc_and_print(dev,
 996                                 BTRFS_DEV_STAT_CORRUPTION_ERRS);
 997         }
 998
 999         if (sctx->readonly) {
1000                 ASSERT(!sctx->is_dev_replace);
1001                 goto out;
1002         }
1003
1004         /*
1005          * now build and submit the bios for the other mirrors, check
1006          * checksums.
1007          * First try to pick the mirror which is completely without I/O
1008          * errors and also does not have a checksum error.
1009          * If one is found, and if a checksum is present, the full block
1010          * that is known to contain an error is rewritten. Afterwards
1011          * the block is known to be corrected.
1012          * If a mirror is found which is completely correct, and no
1013          * checksum is present, only those pages are rewritten that had
1014          * an I/O error in the block to be repaired, since it cannot be
1015          * determined, which copy of the other pages is better (and it
1016          * could happen otherwise that a correct page would be
1017          * overwritten by a bad one).
1018          */
1019         for (mirror_index = 0; ;mirror_index++) {
1020                 struct scrub_block *sblock_other;
1021
1022                 if (mirror_index == failed_mirror_index)
1023                         continue;
1024
1025                 /* raid56's mirror can be more than BTRFS_MAX_MIRRORS */
1026                 if (!scrub_is_page_on_raid56(sblock_bad->pagev[0])) {
1027                         if (mirror_index >= BTRFS_MAX_MIRRORS)
1028                                 break;
1029                         if (!sblocks_for_recheck[mirror_index].page_count)
1030                                 break;
1031
1032                         sblock_other = sblocks_for_recheck + mirror_index;
1033                 } else {
1034                         struct scrub_recover *r = sblock_bad->pagev[0]->recover;
1035                         int max_allowed = r->bbio->num_stripes -
1036                                                 r->bbio->num_tgtdevs;
1037
1038                         if (mirror_index >= max_allowed)
1039                                 break;
1040                         if (!sblocks_for_recheck[1].page_count)
1041                                 break;
1042
1043                         ASSERT(failed_mirror_index == 0);
1044                         sblock_other = sblocks_for_recheck + 1;
1045                         sblock_other->pagev[0]->mirror_num = 1 + mirror_index;
1046                 }
1047
1048                 /* build and submit the bios, check checksums */
1049                 scrub_recheck_block(fs_info, sblock_other, 0);
1050
1051                 if (!sblock_other->header_error &&
1052                     !sblock_other->checksum_error &&
1053                     sblock_other->no_io_error_seen) {
1054                         if (sctx->is_dev_replace) {
1055                                 scrub_write_block_to_dev_replace(sblock_other);
1056                                 goto corrected_error;
1057                         } else {
1058                                 ret = scrub_repair_block_from_good_copy(
1059                                                 sblock_bad, sblock_other);
1060                                 if (!ret)
1061                                         goto corrected_error;
1062                         }
1063                 }
1064         }
1065
1066         if (sblock_bad->no_io_error_seen && !sctx->is_dev_replace)
1067                 goto did_not_correct_error;
1068
1069         /*
1070          * In case of I/O errors in the area that is supposed to be
1071          * repaired, continue by picking good copies of those pages.
1072          * Select the good pages from mirrors to rewrite bad pages from
1073          * the area to fix. Afterwards verify the checksum of the block
1074          * that is supposed to be repaired. This verification step is
1075          * only done for the purpose of statistic counting and for the
1076          * final scrub report, whether errors remain.
1077          * A perfect algorithm could make use of the checksum and try
1078          * all possible combinations of pages from the different mirrors
1079          * until the checksum verification succeeds. For example, when
1080          * the 2nd page of mirror #1 faces I/O errors, and the 2nd page
1081          * of mirror #2 is readable but the final checksum test fails,
1082          * then the 2nd page of mirror #3 could be tried, whether now
1083          * the final checksum succeeds. But this would be a rare
1084          * exception and is therefore not implemented. At least it is
1085          * avoided that the good copy is overwritten.
1086          * A more useful improvement would be to pick the sectors
1087          * without I/O error based on sector sizes (512 bytes on legacy
1088          * disks) instead of on PAGE_SIZE. Then maybe 512 byte of one
1089          * mirror could be repaired by taking 512 byte of a different
1090          * mirror, even if other 512 byte sectors in the same PAGE_SIZE
1091          * area are unreadable.
1092          */
1093         success = 1;
1094         for (page_num = 0; page_num < sblock_bad->page_count;
1095              page_num++) {
1096                 struct scrub_page *page_bad = sblock_bad->pagev[page_num];
1097                 struct scrub_block *sblock_other = NULL;
1098
1099                 /* skip no-io-error page in scrub */
1100                 if (!page_bad->io_error && !sctx->is_dev_replace)
1101                         continue;
1102
1103                 if (scrub_is_page_on_raid56(sblock_bad->pagev[0])) {
1104                         /*
1105                          * In case of dev replace, if raid56 rebuild process
1106                          * didn't work out correct data, then copy the content
1107                          * in sblock_bad to make sure target device is identical
1108                          * to source device, instead of writing garbage data in
1109                          * sblock_for_recheck array to target device.
1110                          */
1111                         sblock_other = NULL;
1112                 } else if (page_bad->io_error) {
1113                         /* try to find no-io-error page in mirrors */
1114                         for (mirror_index = 0;
1115                              mirror_index < BTRFS_MAX_MIRRORS &&
1116                              sblocks_for_recheck[mirror_index].page_count > 0;
1117                              mirror_index++) {
1118                                 if (!sblocks_for_recheck[mirror_index].
1119                                     pagev[page_num]->io_error) {
1120                                         sblock_other = sblocks_for_recheck +
1121                                                        mirror_index;
1122                                         break;
1123                                 }
1124                         }
1125                         if (!sblock_other)
1126                                 success = 0;
1127                 }
1128
1129                 if (sctx->is_dev_replace) {
1130                         /*
1131                          * did not find a mirror to fetch the page
1132                          * from. scrub_write_page_to_dev_replace()
1133                          * handles this case (page->io_error), by
1134                          * filling the block with zeros before
1135                          * submitting the write request
1136                          */
1137                         if (!sblock_other)
1138                                 sblock_other = sblock_bad;
1139
1140                         if (scrub_write_page_to_dev_replace(sblock_other,
1141                                                             page_num) != 0) {
1142                                 atomic64_inc(
1143                                         &fs_info->dev_replace.num_write_errors);
1144                                 success = 0;
1145                         }
1146                 } else if (sblock_other) {
1147                         ret = scrub_repair_page_from_good_copy(sblock_bad,
1148                                                                sblock_other,
1149                                                                page_num, 0);
1150                         if (0 == ret)
1151                                 page_bad->io_error = 0;
1152                         else
1153                                 success = 0;
1154                 }
1155         }
1156
1157         if (success && !sctx->is_dev_replace) {
1158                 if (is_metadata || have_csum) {
1159                         /*
1160                          * need to verify the checksum now that all
1161                          * sectors on disk are repaired (the write
1162                          * request for data to be repaired is on its way).
1163                          * Just be lazy and use scrub_recheck_block()
1164                          * which re-reads the data before the checksum
1165                          * is verified, but most likely the data comes out
1166                          * of the page cache.
1167                          */
1168                         scrub_recheck_block(fs_info, sblock_bad, 1);
1169                         if (!sblock_bad->header_error &&
1170                             !sblock_bad->checksum_error &&
1171                             sblock_bad->no_io_error_seen)
1172                                 goto corrected_error;
1173                         else
1174                                 goto did_not_correct_error;
1175                 } else {
1176 corrected_error:
1177                         spin_lock(&sctx->stat_lock);
1178                         sctx->stat.corrected_errors++;
1179                         sblock_to_check->data_corrected = 1;
1180                         spin_unlock(&sctx->stat_lock);
1181                         btrfs_err_rl_in_rcu(fs_info,
1182                                 "fixed up error at logical %llu on dev %s",
1183                                 logical, rcu_str_deref(dev->name));
1184                 }
1185         } else {
1186 did_not_correct_error:
1187                 spin_lock(&sctx->stat_lock);
1188                 sctx->stat.uncorrectable_errors++;
1189                 spin_unlock(&sctx->stat_lock);
1190                 btrfs_err_rl_in_rcu(fs_info,
1191                         "unable to fixup (regular) error at logical %llu on dev %s",
1192                         logical, rcu_str_deref(dev->name));
1193         }
1194
1195 out:
1196         if (sblocks_for_recheck) {
1197                 for (mirror_index = 0; mirror_index < BTRFS_MAX_MIRRORS;
1198                      mirror_index++) {
1199                         struct scrub_block *sblock = sblocks_for_recheck +
1200                                                      mirror_index;
1201                         struct scrub_recover *recover;
1202                         int page_index;
1203
1204                         for (page_index = 0; page_index < sblock->page_count;
1205                              page_index++) {
1206                                 sblock->pagev[page_index]->sblock = NULL;
1207                                 recover = sblock->pagev[page_index]->recover;
1208                                 if (recover) {
1209                                         scrub_put_recover(fs_info, recover);
1210                                         sblock->pagev[page_index]->recover =
1211                                                                         NULL;
1212                                 }
1213                                 scrub_page_put(sblock->pagev[page_index]);
1214                         }
1215                 }
1216                 kfree(sblocks_for_recheck);
1217         }
1218
1219         ret = unlock_full_stripe(fs_info, logical, full_stripe_locked);
1220         memalloc_nofs_restore(nofs_flag);
1221         if (ret < 0)
1222                 return ret;
1223         return 0;
1224 }
1225
1226 static inline int scrub_nr_raid_mirrors(struct btrfs_bio *bbio)
1227 {
1228         if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID5)
1229                 return 2;
1230         else if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID6)
1231                 return 3;
1232         else
1233                 return (int)bbio->num_stripes;
1234 }
1235
1236 static inline void scrub_stripe_index_and_offset(u64 logical, u64 map_type,
1237                                                  u64 *raid_map,
1238                                                  u64 mapped_length,
1239                                                  int nstripes, int mirror,
1240                                                  int *stripe_index,
1241                                                  u64 *stripe_offset)
1242 {
1243         int i;
1244
1245         if (map_type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
1246                 /* RAID5/6 */
1247                 for (i = 0; i < nstripes; i++) {
1248                         if (raid_map[i] == RAID6_Q_STRIPE ||
1249                             raid_map[i] == RAID5_P_STRIPE)
1250                                 continue;
1251
1252                         if (logical >= raid_map[i] &&
1253                             logical < raid_map[i] + mapped_length)
1254                                 break;
1255                 }
1256
1257                 *stripe_index = i;
1258                 *stripe_offset = logical - raid_map[i];
1259         } else {
1260                 /* The other RAID type */
1261                 *stripe_index = mirror;
1262                 *stripe_offset = 0;
1263         }
1264 }
1265
1266 static int scrub_setup_recheck_block(struct scrub_block *original_sblock,
1267                                      struct scrub_block *sblocks_for_recheck)
1268 {
1269         struct scrub_ctx *sctx = original_sblock->sctx;
1270         struct btrfs_fs_info *fs_info = sctx->fs_info;
1271         u64 length = original_sblock->page_count * PAGE_SIZE;
1272         u64 logical = original_sblock->pagev[0]->logical;
1273         u64 generation = original_sblock->pagev[0]->generation;
1274         u64 flags = original_sblock->pagev[0]->flags;
1275         u64 have_csum = original_sblock->pagev[0]->have_csum;
1276         struct scrub_recover *recover;
1277         struct btrfs_bio *bbio;
1278         u64 sublen;
1279         u64 mapped_length;
1280         u64 stripe_offset;
1281         int stripe_index;
1282         int page_index = 0;
1283         int mirror_index;
1284         int nmirrors;
1285         int ret;
1286
1287         /*
1288          * note: the two members refs and outstanding_pages
1289          * are not used (and not set) in the blocks that are used for
1290          * the recheck procedure
1291          */
1292
1293         while (length > 0) {
1294                 sublen = min_t(u64, length, PAGE_SIZE);
1295                 mapped_length = sublen;
1296                 bbio = NULL;
1297
1298                 /*
1299                  * with a length of PAGE_SIZE, each returned stripe
1300                  * represents one mirror
1301                  */
1302                 btrfs_bio_counter_inc_blocked(fs_info);
1303                 ret = btrfs_map_sblock(fs_info, BTRFS_MAP_GET_READ_MIRRORS,
1304                                 logical, &mapped_length, &bbio);
1305                 if (ret || !bbio || mapped_length < sublen) {
1306                         btrfs_put_bbio(bbio);
1307                         btrfs_bio_counter_dec(fs_info);
1308                         return -EIO;
1309                 }
1310
1311                 recover = kzalloc(sizeof(struct scrub_recover), GFP_NOFS);
1312                 if (!recover) {
1313                         btrfs_put_bbio(bbio);
1314                         btrfs_bio_counter_dec(fs_info);
1315                         return -ENOMEM;
1316                 }
1317
1318                 refcount_set(&recover->refs, 1);
1319                 recover->bbio = bbio;
1320                 recover->map_length = mapped_length;
1321
1322                 BUG_ON(page_index >= SCRUB_MAX_PAGES_PER_BLOCK);
1323
1324                 nmirrors = min(scrub_nr_raid_mirrors(bbio), BTRFS_MAX_MIRRORS);
1325
1326                 for (mirror_index = 0; mirror_index < nmirrors;
1327                      mirror_index++) {
1328                         struct scrub_block *sblock;
1329                         struct scrub_page *page;
1330
1331                         sblock = sblocks_for_recheck + mirror_index;
1332                         sblock->sctx = sctx;
1333
1334                         page = kzalloc(sizeof(*page), GFP_NOFS);
1335                         if (!page) {
1336 leave_nomem:
1337                                 spin_lock(&sctx->stat_lock);
1338                                 sctx->stat.malloc_errors++;
1339                                 spin_unlock(&sctx->stat_lock);
1340                                 scrub_put_recover(fs_info, recover);
1341                                 return -ENOMEM;
1342                         }
1343                         scrub_page_get(page);
1344                         sblock->pagev[page_index] = page;
1345                         page->sblock = sblock;
1346                         page->flags = flags;
1347                         page->generation = generation;
1348                         page->logical = logical;
1349                         page->have_csum = have_csum;
1350                         if (have_csum)
1351                                 memcpy(page->csum,
1352                                        original_sblock->pagev[0]->csum,
1353                                        sctx->csum_size);
1354
1355                         scrub_stripe_index_and_offset(logical,
1356                                                       bbio->map_type,
1357                                                       bbio->raid_map,
1358                                                       mapped_length,
1359                                                       bbio->num_stripes -
1360                                                       bbio->num_tgtdevs,
1361                                                       mirror_index,
1362                                                       &stripe_index,
1363                                                       &stripe_offset);
1364                         page->physical = bbio->stripes[stripe_index].physical +
1365                                          stripe_offset;
1366                         page->dev = bbio->stripes[stripe_index].dev;
1367
1368                         BUG_ON(page_index >= original_sblock->page_count);
1369                         page->physical_for_dev_replace =
1370                                 original_sblock->pagev[page_index]->
1371                                 physical_for_dev_replace;
1372                         /* for missing devices, dev->bdev is NULL */
1373                         page->mirror_num = mirror_index + 1;
1374                         sblock->page_count++;
1375                         page->page = alloc_page(GFP_NOFS);
1376                         if (!page->page)
1377                                 goto leave_nomem;
1378
1379                         scrub_get_recover(recover);
1380                         page->recover = recover;
1381                 }
1382                 scrub_put_recover(fs_info, recover);
1383                 length -= sublen;
1384                 logical += sublen;
1385                 page_index++;
1386         }
1387
1388         return 0;
1389 }
1390
1391 static void scrub_bio_wait_endio(struct bio *bio)
1392 {
1393         complete(bio->bi_private);
1394 }
1395
1396 static int scrub_submit_raid56_bio_wait(struct btrfs_fs_info *fs_info,
1397                                         struct bio *bio,
1398                                         struct scrub_page *page)
1399 {
1400         DECLARE_COMPLETION_ONSTACK(done);
1401         int ret;
1402         int mirror_num;
1403
1404         bio->bi_iter.bi_sector = page->logical >> 9;
1405         bio->bi_private = &done;
1406         bio->bi_end_io = scrub_bio_wait_endio;
1407
1408         mirror_num = page->sblock->pagev[0]->mirror_num;
1409         ret = raid56_parity_recover(fs_info, bio, page->recover->bbio,
1410                                     page->recover->map_length,
1411                                     mirror_num, 0);
1412         if (ret)
1413                 return ret;
1414
1415         wait_for_completion_io(&done);
1416         return blk_status_to_errno(bio->bi_status);
1417 }
1418
1419 static void scrub_recheck_block_on_raid56(struct btrfs_fs_info *fs_info,
1420                                           struct scrub_block *sblock)
1421 {
1422         struct scrub_page *first_page = sblock->pagev[0];
1423         struct bio *bio;
1424         int page_num;
1425
1426         /* All pages in sblock belong to the same stripe on the same device. */
1427         ASSERT(first_page->dev);
1428         if (!first_page->dev->bdev)
1429                 goto out;
1430
1431         bio = btrfs_io_bio_alloc(BIO_MAX_PAGES);
1432         bio_set_dev(bio, first_page->dev->bdev);
1433
1434         for (page_num = 0; page_num < sblock->page_count; page_num++) {
1435                 struct scrub_page *page = sblock->pagev[page_num];
1436
1437                 WARN_ON(!page->page);
1438                 bio_add_page(bio, page->page, PAGE_SIZE, 0);
1439         }
1440
1441         if (scrub_submit_raid56_bio_wait(fs_info, bio, first_page)) {
1442                 bio_put(bio);
1443                 goto out;
1444         }
1445
1446         bio_put(bio);
1447
1448         scrub_recheck_block_checksum(sblock);
1449
1450         return;
1451 out:
1452         for (page_num = 0; page_num < sblock->page_count; page_num++)
1453                 sblock->pagev[page_num]->io_error = 1;
1454
1455         sblock->no_io_error_seen = 0;
1456 }
1457
1458 /*
1459  * this function will check the on disk data for checksum errors, header
1460  * errors and read I/O errors. If any I/O errors happen, the exact pages
1461  * which are errored are marked as being bad. The goal is to enable scrub
1462  * to take those pages that are not errored from all the mirrors so that
1463  * the pages that are errored in the just handled mirror can be repaired.
1464  */
1465 static void scrub_recheck_block(struct btrfs_fs_info *fs_info,
1466                                 struct scrub_block *sblock,
1467                                 int retry_failed_mirror)
1468 {
1469         int page_num;
1470
1471         sblock->no_io_error_seen = 1;
1472
1473         /* short cut for raid56 */
1474         if (!retry_failed_mirror && scrub_is_page_on_raid56(sblock->pagev[0]))
1475                 return scrub_recheck_block_on_raid56(fs_info, sblock);
1476
1477         for (page_num = 0; page_num < sblock->page_count; page_num++) {
1478                 struct bio *bio;
1479                 struct scrub_page *page = sblock->pagev[page_num];
1480
1481                 if (page->dev->bdev == NULL) {
1482                         page->io_error = 1;
1483                         sblock->no_io_error_seen = 0;
1484                         continue;
1485                 }
1486
1487                 WARN_ON(!page->page);
1488                 bio = btrfs_io_bio_alloc(1);
1489                 bio_set_dev(bio, page->dev->bdev);
1490
1491                 bio_add_page(bio, page->page, PAGE_SIZE, 0);
1492                 bio->bi_iter.bi_sector = page->physical >> 9;
1493                 bio->bi_opf = REQ_OP_READ;
1494
1495                 if (btrfsic_submit_bio_wait(bio)) {
1496                         page->io_error = 1;
1497                         sblock->no_io_error_seen = 0;
1498                 }
1499
1500                 bio_put(bio);
1501         }
1502
1503         if (sblock->no_io_error_seen)
1504                 scrub_recheck_block_checksum(sblock);
1505 }
1506
1507 static inline int scrub_check_fsid(u8 fsid[],
1508                                    struct scrub_page *spage)
1509 {
1510         struct btrfs_fs_devices *fs_devices = spage->dev->fs_devices;
1511         int ret;
1512
1513         ret = memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE);
1514         return !ret;
1515 }
1516
1517 static void scrub_recheck_block_checksum(struct scrub_block *sblock)
1518 {
1519         sblock->header_error = 0;
1520         sblock->checksum_error = 0;
1521         sblock->generation_error = 0;
1522
1523         if (sblock->pagev[0]->flags & BTRFS_EXTENT_FLAG_DATA)
1524                 scrub_checksum_data(sblock);
1525         else
1526                 scrub_checksum_tree_block(sblock);
1527 }
1528
1529 static int scrub_repair_block_from_good_copy(struct scrub_block *sblock_bad,
1530                                              struct scrub_block *sblock_good)
1531 {
1532         int page_num;
1533         int ret = 0;
1534
1535         for (page_num = 0; page_num < sblock_bad->page_count; page_num++) {
1536                 int ret_sub;
1537
1538                 ret_sub = scrub_repair_page_from_good_copy(sblock_bad,
1539                                                            sblock_good,
1540                                                            page_num, 1);
1541                 if (ret_sub)
1542                         ret = ret_sub;
1543         }
1544
1545         return ret;
1546 }
1547
1548 static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
1549                                             struct scrub_block *sblock_good,
1550                                             int page_num, int force_write)
1551 {
1552         struct scrub_page *page_bad = sblock_bad->pagev[page_num];
1553         struct scrub_page *page_good = sblock_good->pagev[page_num];
1554         struct btrfs_fs_info *fs_info = sblock_bad->sctx->fs_info;
1555
1556         BUG_ON(page_bad->page == NULL);
1557         BUG_ON(page_good->page == NULL);
1558         if (force_write || sblock_bad->header_error ||
1559             sblock_bad->checksum_error || page_bad->io_error) {
1560                 struct bio *bio;
1561                 int ret;
1562
1563                 if (!page_bad->dev->bdev) {
1564                         btrfs_warn_rl(fs_info,
1565                                 "scrub_repair_page_from_good_copy(bdev == NULL) is unexpected");
1566                         return -EIO;
1567                 }
1568
1569                 bio = btrfs_io_bio_alloc(1);
1570                 bio_set_dev(bio, page_bad->dev->bdev);
1571                 bio->bi_iter.bi_sector = page_bad->physical >> 9;
1572                 bio->bi_opf = REQ_OP_WRITE;
1573
1574                 ret = bio_add_page(bio, page_good->page, PAGE_SIZE, 0);
1575                 if (PAGE_SIZE != ret) {
1576                         bio_put(bio);
1577                         return -EIO;
1578                 }
1579
1580                 if (btrfsic_submit_bio_wait(bio)) {
1581                         btrfs_dev_stat_inc_and_print(page_bad->dev,
1582                                 BTRFS_DEV_STAT_WRITE_ERRS);
1583                         atomic64_inc(&fs_info->dev_replace.num_write_errors);
1584                         bio_put(bio);
1585                         return -EIO;
1586                 }
1587                 bio_put(bio);
1588         }
1589
1590         return 0;
1591 }
1592
1593 static void scrub_write_block_to_dev_replace(struct scrub_block *sblock)
1594 {
1595         struct btrfs_fs_info *fs_info = sblock->sctx->fs_info;
1596         int page_num;
1597
1598         /*
1599          * This block is used for the check of the parity on the source device,
1600          * so the data needn't be written into the destination device.
1601          */
1602         if (sblock->sparity)
1603                 return;
1604
1605         for (page_num = 0; page_num < sblock->page_count; page_num++) {
1606                 int ret;
1607
1608                 ret = scrub_write_page_to_dev_replace(sblock, page_num);
1609                 if (ret)
1610                         atomic64_inc(&fs_info->dev_replace.num_write_errors);
1611         }
1612 }
1613
1614 static int scrub_write_page_to_dev_replace(struct scrub_block *sblock,
1615                                            int page_num)
1616 {
1617         struct scrub_page *spage = sblock->pagev[page_num];
1618
1619         BUG_ON(spage->page == NULL);
1620         if (spage->io_error) {
1621                 void *mapped_buffer = kmap_atomic(spage->page);
1622
1623                 clear_page(mapped_buffer);
1624                 flush_dcache_page(spage->page);
1625                 kunmap_atomic(mapped_buffer);
1626         }
1627         return scrub_add_page_to_wr_bio(sblock->sctx, spage);
1628 }
1629
1630 static int scrub_add_page_to_wr_bio(struct scrub_ctx *sctx,
1631                                     struct scrub_page *spage)
1632 {
1633         struct scrub_bio *sbio;
1634         int ret;
1635
1636         mutex_lock(&sctx->wr_lock);
1637 again:
1638         if (!sctx->wr_curr_bio) {
1639                 sctx->wr_curr_bio = kzalloc(sizeof(*sctx->wr_curr_bio),
1640                                               GFP_KERNEL);
1641                 if (!sctx->wr_curr_bio) {
1642                         mutex_unlock(&sctx->wr_lock);
1643                         return -ENOMEM;
1644                 }
1645                 sctx->wr_curr_bio->sctx = sctx;
1646                 sctx->wr_curr_bio->page_count = 0;
1647         }
1648         sbio = sctx->wr_curr_bio;
1649         if (sbio->page_count == 0) {
1650                 struct bio *bio;
1651
1652                 sbio->physical = spage->physical_for_dev_replace;
1653                 sbio->logical = spage->logical;
1654                 sbio->dev = sctx->wr_tgtdev;
1655                 bio = sbio->bio;
1656                 if (!bio) {
1657                         bio = btrfs_io_bio_alloc(sctx->pages_per_wr_bio);
1658                         sbio->bio = bio;
1659                 }
1660
1661                 bio->bi_private = sbio;
1662                 bio->bi_end_io = scrub_wr_bio_end_io;
1663                 bio_set_dev(bio, sbio->dev->bdev);
1664                 bio->bi_iter.bi_sector = sbio->physical >> 9;
1665                 bio->bi_opf = REQ_OP_WRITE;
1666                 sbio->status = 0;
1667         } else if (sbio->physical + sbio->page_count * PAGE_SIZE !=
1668                    spage->physical_for_dev_replace ||
1669                    sbio->logical + sbio->page_count * PAGE_SIZE !=
1670                    spage->logical) {
1671                 scrub_wr_submit(sctx);
1672                 goto again;
1673         }
1674
1675         ret = bio_add_page(sbio->bio, spage->page, PAGE_SIZE, 0);
1676         if (ret != PAGE_SIZE) {
1677                 if (sbio->page_count < 1) {
1678                         bio_put(sbio->bio);
1679                         sbio->bio = NULL;
1680                         mutex_unlock(&sctx->wr_lock);
1681                         return -EIO;
1682                 }
1683                 scrub_wr_submit(sctx);
1684                 goto again;
1685         }
1686
1687         sbio->pagev[sbio->page_count] = spage;
1688         scrub_page_get(spage);
1689         sbio->page_count++;
1690         if (sbio->page_count == sctx->pages_per_wr_bio)
1691                 scrub_wr_submit(sctx);
1692         mutex_unlock(&sctx->wr_lock);
1693
1694         return 0;
1695 }
1696
1697 static void scrub_wr_submit(struct scrub_ctx *sctx)
1698 {
1699         struct scrub_bio *sbio;
1700
1701         if (!sctx->wr_curr_bio)
1702                 return;
1703
1704         sbio = sctx->wr_curr_bio;
1705         sctx->wr_curr_bio = NULL;
1706         WARN_ON(!sbio->bio->bi_disk);
1707         scrub_pending_bio_inc(sctx);
1708         /* process all writes in a single worker thread. Then the block layer
1709          * orders the requests before sending them to the driver which
1710          * doubled the write performance on spinning disks when measured
1711          * with Linux 3.5 */
1712         btrfsic_submit_bio(sbio->bio);
1713 }
1714
1715 static void scrub_wr_bio_end_io(struct bio *bio)
1716 {
1717         struct scrub_bio *sbio = bio->bi_private;
1718         struct btrfs_fs_info *fs_info = sbio->dev->fs_info;
1719
1720         sbio->status = bio->bi_status;
1721         sbio->bio = bio;
1722
1723         btrfs_init_work(&sbio->work, scrub_wr_bio_end_io_worker, NULL, NULL);
1724         btrfs_queue_work(fs_info->scrub_wr_completion_workers, &sbio->work);
1725 }
1726
1727 static void scrub_wr_bio_end_io_worker(struct btrfs_work *work)
1728 {
1729         struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
1730         struct scrub_ctx *sctx = sbio->sctx;
1731         int i;
1732
1733         WARN_ON(sbio->page_count > SCRUB_PAGES_PER_WR_BIO);
1734         if (sbio->status) {
1735                 struct btrfs_dev_replace *dev_replace =
1736                         &sbio->sctx->fs_info->dev_replace;
1737
1738                 for (i = 0; i < sbio->page_count; i++) {
1739                         struct scrub_page *spage = sbio->pagev[i];
1740
1741                         spage->io_error = 1;
1742                         atomic64_inc(&dev_replace->num_write_errors);
1743                 }
1744         }
1745
1746         for (i = 0; i < sbio->page_count; i++)
1747                 scrub_page_put(sbio->pagev[i]);
1748
1749         bio_put(sbio->bio);
1750         kfree(sbio);
1751         scrub_pending_bio_dec(sctx);
1752 }
1753
1754 static int scrub_checksum(struct scrub_block *sblock)
1755 {
1756         u64 flags;
1757         int ret;
1758
1759         /*
1760          * No need to initialize these stats currently,
1761          * because this function only use return value
1762          * instead of these stats value.
1763          *
1764          * Todo:
1765          * always use stats
1766          */
1767         sblock->header_error = 0;
1768         sblock->generation_error = 0;
1769         sblock->checksum_error = 0;
1770
1771         WARN_ON(sblock->page_count < 1);
1772         flags = sblock->pagev[0]->flags;
1773         ret = 0;
1774         if (flags & BTRFS_EXTENT_FLAG_DATA)
1775                 ret = scrub_checksum_data(sblock);
1776         else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1777                 ret = scrub_checksum_tree_block(sblock);
1778         else if (flags & BTRFS_EXTENT_FLAG_SUPER)
1779                 (void)scrub_checksum_super(sblock);
1780         else
1781                 WARN_ON(1);
1782         if (ret)
1783                 scrub_handle_errored_block(sblock);
1784
1785         return ret;
1786 }
1787
1788 static int scrub_checksum_data(struct scrub_block *sblock)
1789 {
1790         struct scrub_ctx *sctx = sblock->sctx;
1791         struct btrfs_fs_info *fs_info = sctx->fs_info;
1792         SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
1793         u8 csum[BTRFS_CSUM_SIZE];
1794         u8 *on_disk_csum;
1795         struct page *page;
1796         void *buffer;
1797         u64 len;
1798         int index;
1799
1800         BUG_ON(sblock->page_count < 1);
1801         if (!sblock->pagev[0]->have_csum)
1802                 return 0;
1803
1804         shash->tfm = fs_info->csum_shash;
1805         crypto_shash_init(shash);
1806
1807         on_disk_csum = sblock->pagev[0]->csum;
1808         page = sblock->pagev[0]->page;
1809         buffer = kmap_atomic(page);
1810
1811         len = sctx->fs_info->sectorsize;
1812         index = 0;
1813         for (;;) {
1814                 u64 l = min_t(u64, len, PAGE_SIZE);
1815
1816                 crypto_shash_update(shash, buffer, l);
1817                 kunmap_atomic(buffer);
1818                 len -= l;
1819                 if (len == 0)
1820                         break;
1821                 index++;
1822                 BUG_ON(index >= sblock->page_count);
1823                 BUG_ON(!sblock->pagev[index]->page);
1824                 page = sblock->pagev[index]->page;
1825                 buffer = kmap_atomic(page);
1826         }
1827
1828         crypto_shash_final(shash, csum);
1829         if (memcmp(csum, on_disk_csum, sctx->csum_size))
1830                 sblock->checksum_error = 1;
1831
1832         return sblock->checksum_error;
1833 }
1834
1835 static int scrub_checksum_tree_block(struct scrub_block *sblock)
1836 {
1837         struct scrub_ctx *sctx = sblock->sctx;
1838         struct btrfs_header *h;
1839         struct btrfs_fs_info *fs_info = sctx->fs_info;
1840         SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
1841         u8 calculated_csum[BTRFS_CSUM_SIZE];
1842         u8 on_disk_csum[BTRFS_CSUM_SIZE];
1843         struct page *page;
1844         void *mapped_buffer;
1845         u64 mapped_size;
1846         void *p;
1847         u64 len;
1848         int index;
1849
1850         shash->tfm = fs_info->csum_shash;
1851         crypto_shash_init(shash);
1852
1853         BUG_ON(sblock->page_count < 1);
1854         page = sblock->pagev[0]->page;
1855         mapped_buffer = kmap_atomic(page);
1856         h = (struct btrfs_header *)mapped_buffer;
1857         memcpy(on_disk_csum, h->csum, sctx->csum_size);
1858
1859         /*
1860          * we don't use the getter functions here, as we
1861          * a) don't have an extent buffer and
1862          * b) the page is already kmapped
1863          */
1864         if (sblock->pagev[0]->logical != btrfs_stack_header_bytenr(h))
1865                 sblock->header_error = 1;
1866
1867         if (sblock->pagev[0]->generation != btrfs_stack_header_generation(h)) {
1868                 sblock->header_error = 1;
1869                 sblock->generation_error = 1;
1870         }
1871
1872         if (!scrub_check_fsid(h->fsid, sblock->pagev[0]))
1873                 sblock->header_error = 1;
1874
1875         if (memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
1876                    BTRFS_UUID_SIZE))
1877                 sblock->header_error = 1;
1878
1879         len = sctx->fs_info->nodesize - BTRFS_CSUM_SIZE;
1880         mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE;
1881         p = ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE;
1882         index = 0;
1883         for (;;) {
1884                 u64 l = min_t(u64, len, mapped_size);
1885
1886                 crypto_shash_update(shash, p, l);
1887                 kunmap_atomic(mapped_buffer);
1888                 len -= l;
1889                 if (len == 0)
1890                         break;
1891                 index++;
1892                 BUG_ON(index >= sblock->page_count);
1893                 BUG_ON(!sblock->pagev[index]->page);
1894                 page = sblock->pagev[index]->page;
1895                 mapped_buffer = kmap_atomic(page);
1896                 mapped_size = PAGE_SIZE;
1897                 p = mapped_buffer;
1898         }
1899
1900         crypto_shash_final(shash, calculated_csum);
1901         if (memcmp(calculated_csum, on_disk_csum, sctx->csum_size))
1902                 sblock->checksum_error = 1;
1903
1904         return sblock->header_error || sblock->checksum_error;
1905 }
1906
1907 static int scrub_checksum_super(struct scrub_block *sblock)
1908 {
1909         struct btrfs_super_block *s;
1910         struct scrub_ctx *sctx = sblock->sctx;
1911         struct btrfs_fs_info *fs_info = sctx->fs_info;
1912         SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
1913         u8 calculated_csum[BTRFS_CSUM_SIZE];
1914         u8 on_disk_csum[BTRFS_CSUM_SIZE];
1915         struct page *page;
1916         void *mapped_buffer;
1917         u64 mapped_size;
1918         void *p;
1919         int fail_gen = 0;
1920         int fail_cor = 0;
1921         u64 len;
1922         int index;
1923
1924         shash->tfm = fs_info->csum_shash;
1925         crypto_shash_init(shash);
1926
1927         BUG_ON(sblock->page_count < 1);
1928         page = sblock->pagev[0]->page;
1929         mapped_buffer = kmap_atomic(page);
1930         s = (struct btrfs_super_block *)mapped_buffer;
1931         memcpy(on_disk_csum, s->csum, sctx->csum_size);
1932
1933         if (sblock->pagev[0]->logical != btrfs_super_bytenr(s))
1934                 ++fail_cor;
1935
1936         if (sblock->pagev[0]->generation != btrfs_super_generation(s))
1937                 ++fail_gen;
1938
1939         if (!scrub_check_fsid(s->fsid, sblock->pagev[0]))
1940                 ++fail_cor;
1941
1942         len = BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE;
1943         mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE;
1944         p = ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE;
1945         index = 0;
1946         for (;;) {
1947                 u64 l = min_t(u64, len, mapped_size);
1948
1949                 crypto_shash_update(shash, p, l);
1950                 kunmap_atomic(mapped_buffer);
1951                 len -= l;
1952                 if (len == 0)
1953                         break;
1954                 index++;
1955                 BUG_ON(index >= sblock->page_count);
1956                 BUG_ON(!sblock->pagev[index]->page);
1957                 page = sblock->pagev[index]->page;
1958                 mapped_buffer = kmap_atomic(page);
1959                 mapped_size = PAGE_SIZE;
1960                 p = mapped_buffer;
1961         }
1962
1963         crypto_shash_final(shash, calculated_csum);
1964         if (memcmp(calculated_csum, on_disk_csum, sctx->csum_size))
1965                 ++fail_cor;
1966
1967         if (fail_cor + fail_gen) {
1968                 /*
1969                  * if we find an error in a super block, we just report it.
1970                  * They will get written with the next transaction commit
1971                  * anyway
1972                  */
1973                 spin_lock(&sctx->stat_lock);
1974                 ++sctx->stat.super_errors;
1975                 spin_unlock(&sctx->stat_lock);
1976                 if (fail_cor)
1977                         btrfs_dev_stat_inc_and_print(sblock->pagev[0]->dev,
1978                                 BTRFS_DEV_STAT_CORRUPTION_ERRS);
1979                 else
1980                         btrfs_dev_stat_inc_and_print(sblock->pagev[0]->dev,
1981                                 BTRFS_DEV_STAT_GENERATION_ERRS);
1982         }
1983
1984         return fail_cor + fail_gen;
1985 }
1986
1987 static void scrub_block_get(struct scrub_block *sblock)
1988 {
1989         refcount_inc(&sblock->refs);
1990 }
1991
1992 static void scrub_block_put(struct scrub_block *sblock)
1993 {
1994         if (refcount_dec_and_test(&sblock->refs)) {
1995                 int i;
1996
1997                 if (sblock->sparity)
1998                         scrub_parity_put(sblock->sparity);
1999
2000                 for (i = 0; i < sblock->page_count; i++)
2001                         scrub_page_put(sblock->pagev[i]);
2002                 kfree(sblock);
2003         }
2004 }
2005
2006 static void scrub_page_get(struct scrub_page *spage)
2007 {
2008         atomic_inc(&spage->refs);
2009 }
2010
2011 static void scrub_page_put(struct scrub_page *spage)
2012 {
2013         if (atomic_dec_and_test(&spage->refs)) {
2014                 if (spage->page)
2015                         __free_page(spage->page);
2016                 kfree(spage);
2017         }
2018 }
2019
2020 static void scrub_submit(struct scrub_ctx *sctx)
2021 {
2022         struct scrub_bio *sbio;
2023
2024         if (sctx->curr == -1)
2025                 return;
2026
2027         sbio = sctx->bios[sctx->curr];
2028         sctx->curr = -1;
2029         scrub_pending_bio_inc(sctx);
2030         btrfsic_submit_bio(sbio->bio);
2031 }
2032
2033 static int scrub_add_page_to_rd_bio(struct scrub_ctx *sctx,
2034                                     struct scrub_page *spage)
2035 {
2036         struct scrub_block *sblock = spage->sblock;
2037         struct scrub_bio *sbio;
2038         int ret;
2039
2040 again:
2041         /*
2042          * grab a fresh bio or wait for one to become available
2043          */
2044         while (sctx->curr == -1) {
2045                 spin_lock(&sctx->list_lock);
2046                 sctx->curr = sctx->first_free;
2047                 if (sctx->curr != -1) {
2048                         sctx->first_free = sctx->bios[sctx->curr]->next_free;
2049                         sctx->bios[sctx->curr]->next_free = -1;
2050                         sctx->bios[sctx->curr]->page_count = 0;
2051                         spin_unlock(&sctx->list_lock);
2052                 } else {
2053                         spin_unlock(&sctx->list_lock);
2054                         wait_event(sctx->list_wait, sctx->first_free != -1);
2055                 }
2056         }
2057         sbio = sctx->bios[sctx->curr];
2058         if (sbio->page_count == 0) {
2059                 struct bio *bio;
2060
2061                 sbio->physical = spage->physical;
2062                 sbio->logical = spage->logical;
2063                 sbio->dev = spage->dev;
2064                 bio = sbio->bio;
2065                 if (!bio) {
2066                         bio = btrfs_io_bio_alloc(sctx->pages_per_rd_bio);
2067                         sbio->bio = bio;
2068                 }
2069
2070                 bio->bi_private = sbio;
2071                 bio->bi_end_io = scrub_bio_end_io;
2072                 bio_set_dev(bio, sbio->dev->bdev);
2073                 bio->bi_iter.bi_sector = sbio->physical >> 9;
2074                 bio->bi_opf = REQ_OP_READ;
2075                 sbio->status = 0;
2076         } else if (sbio->physical + sbio->page_count * PAGE_SIZE !=
2077                    spage->physical ||
2078                    sbio->logical + sbio->page_count * PAGE_SIZE !=
2079                    spage->logical ||
2080                    sbio->dev != spage->dev) {
2081                 scrub_submit(sctx);
2082                 goto again;
2083         }
2084
2085         sbio->pagev[sbio->page_count] = spage;
2086         ret = bio_add_page(sbio->bio, spage->page, PAGE_SIZE, 0);
2087         if (ret != PAGE_SIZE) {
2088                 if (sbio->page_count < 1) {
2089                         bio_put(sbio->bio);
2090                         sbio->bio = NULL;
2091                         return -EIO;
2092                 }
2093                 scrub_submit(sctx);
2094                 goto again;
2095         }
2096
2097         scrub_block_get(sblock); /* one for the page added to the bio */
2098         atomic_inc(&sblock->outstanding_pages);
2099         sbio->page_count++;
2100         if (sbio->page_count == sctx->pages_per_rd_bio)
2101                 scrub_submit(sctx);
2102
2103         return 0;
2104 }
2105
2106 static void scrub_missing_raid56_end_io(struct bio *bio)
2107 {
2108         struct scrub_block *sblock = bio->bi_private;
2109         struct btrfs_fs_info *fs_info = sblock->sctx->fs_info;
2110
2111         if (bio->bi_status)
2112                 sblock->no_io_error_seen = 0;
2113
2114         bio_put(bio);
2115
2116         btrfs_queue_work(fs_info->scrub_workers, &sblock->work);
2117 }
2118
2119 static void scrub_missing_raid56_worker(struct btrfs_work *work)
2120 {
2121         struct scrub_block *sblock = container_of(work, struct scrub_block, work);
2122         struct scrub_ctx *sctx = sblock->sctx;
2123         struct btrfs_fs_info *fs_info = sctx->fs_info;
2124         u64 logical;
2125         struct btrfs_device *dev;
2126
2127         logical = sblock->pagev[0]->logical;
2128         dev = sblock->pagev[0]->dev;
2129
2130         if (sblock->no_io_error_seen)
2131                 scrub_recheck_block_checksum(sblock);
2132
2133         if (!sblock->no_io_error_seen) {
2134                 spin_lock(&sctx->stat_lock);
2135                 sctx->stat.read_errors++;
2136                 spin_unlock(&sctx->stat_lock);
2137                 btrfs_err_rl_in_rcu(fs_info,
2138                         "IO error rebuilding logical %llu for dev %s",
2139                         logical, rcu_str_deref(dev->name));
2140         } else if (sblock->header_error || sblock->checksum_error) {
2141                 spin_lock(&sctx->stat_lock);
2142                 sctx->stat.uncorrectable_errors++;
2143                 spin_unlock(&sctx->stat_lock);
2144                 btrfs_err_rl_in_rcu(fs_info,
2145                         "failed to rebuild valid logical %llu for dev %s",
2146                         logical, rcu_str_deref(dev->name));
2147         } else {
2148                 scrub_write_block_to_dev_replace(sblock);
2149         }
2150
2151         if (sctx->is_dev_replace && sctx->flush_all_writes) {
2152                 mutex_lock(&sctx->wr_lock);
2153                 scrub_wr_submit(sctx);
2154                 mutex_unlock(&sctx->wr_lock);
2155         }
2156
2157         scrub_block_put(sblock);
2158         scrub_pending_bio_dec(sctx);
2159 }
2160
2161 static void scrub_missing_raid56_pages(struct scrub_block *sblock)
2162 {
2163         struct scrub_ctx *sctx = sblock->sctx;
2164         struct btrfs_fs_info *fs_info = sctx->fs_info;
2165         u64 length = sblock->page_count * PAGE_SIZE;
2166         u64 logical = sblock->pagev[0]->logical;
2167         struct btrfs_bio *bbio = NULL;
2168         struct bio *bio;
2169         struct btrfs_raid_bio *rbio;
2170         int ret;
2171         int i;
2172
2173         btrfs_bio_counter_inc_blocked(fs_info);
2174         ret = btrfs_map_sblock(fs_info, BTRFS_MAP_GET_READ_MIRRORS, logical,
2175                         &length, &bbio);
2176         if (ret || !bbio || !bbio->raid_map)
2177                 goto bbio_out;
2178
2179         if (WARN_ON(!sctx->is_dev_replace ||
2180                     !(bbio->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK))) {
2181                 /*
2182                  * We shouldn't be scrubbing a missing device. Even for dev
2183                  * replace, we should only get here for RAID 5/6. We either
2184                  * managed to mount something with no mirrors remaining or
2185                  * there's a bug in scrub_remap_extent()/btrfs_map_block().
2186                  */
2187                 goto bbio_out;
2188         }
2189
2190         bio = btrfs_io_bio_alloc(0);
2191         bio->bi_iter.bi_sector = logical >> 9;
2192         bio->bi_private = sblock;
2193         bio->bi_end_io = scrub_missing_raid56_end_io;
2194
2195         rbio = raid56_alloc_missing_rbio(fs_info, bio, bbio, length);
2196         if (!rbio)
2197                 goto rbio_out;
2198
2199         for (i = 0; i < sblock->page_count; i++) {
2200                 struct scrub_page *spage = sblock->pagev[i];
2201
2202                 raid56_add_scrub_pages(rbio, spage->page, spage->logical);
2203         }
2204
2205         btrfs_init_work(&sblock->work, scrub_missing_raid56_worker, NULL, NULL);
2206         scrub_block_get(sblock);
2207         scrub_pending_bio_inc(sctx);
2208         raid56_submit_missing_rbio(rbio);
2209         return;
2210
2211 rbio_out:
2212         bio_put(bio);
2213 bbio_out:
2214         btrfs_bio_counter_dec(fs_info);
2215         btrfs_put_bbio(bbio);
2216         spin_lock(&sctx->stat_lock);
2217         sctx->stat.malloc_errors++;
2218         spin_unlock(&sctx->stat_lock);
2219 }
2220
2221 static int scrub_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
2222                        u64 physical, struct btrfs_device *dev, u64 flags,
2223                        u64 gen, int mirror_num, u8 *csum, int force,
2224                        u64 physical_for_dev_replace)
2225 {
2226         struct scrub_block *sblock;
2227         int index;
2228
2229         sblock = kzalloc(sizeof(*sblock), GFP_KERNEL);
2230         if (!sblock) {
2231                 spin_lock(&sctx->stat_lock);
2232                 sctx->stat.malloc_errors++;
2233                 spin_unlock(&sctx->stat_lock);
2234                 return -ENOMEM;
2235         }
2236
2237         /* one ref inside this function, plus one for each page added to
2238          * a bio later on */
2239         refcount_set(&sblock->refs, 1);
2240         sblock->sctx = sctx;
2241         sblock->no_io_error_seen = 1;
2242
2243         for (index = 0; len > 0; index++) {
2244                 struct scrub_page *spage;
2245                 u64 l = min_t(u64, len, PAGE_SIZE);
2246
2247                 spage = kzalloc(sizeof(*spage), GFP_KERNEL);
2248                 if (!spage) {
2249 leave_nomem:
2250                         spin_lock(&sctx->stat_lock);
2251                         sctx->stat.malloc_errors++;
2252                         spin_unlock(&sctx->stat_lock);
2253                         scrub_block_put(sblock);
2254                         return -ENOMEM;
2255                 }
2256                 BUG_ON(index >= SCRUB_MAX_PAGES_PER_BLOCK);
2257                 scrub_page_get(spage);
2258                 sblock->pagev[index] = spage;
2259                 spage->sblock = sblock;
2260                 spage->dev = dev;
2261                 spage->flags = flags;
2262                 spage->generation = gen;
2263                 spage->logical = logical;
2264                 spage->physical = physical;
2265                 spage->physical_for_dev_replace = physical_for_dev_replace;
2266                 spage->mirror_num = mirror_num;
2267                 if (csum) {
2268                         spage->have_csum = 1;
2269                         memcpy(spage->csum, csum, sctx->csum_size);
2270                 } else {
2271                         spage->have_csum = 0;
2272                 }
2273                 sblock->page_count++;
2274                 spage->page = alloc_page(GFP_KERNEL);
2275                 if (!spage->page)
2276                         goto leave_nomem;
2277                 len -= l;
2278                 logical += l;
2279                 physical += l;
2280                 physical_for_dev_replace += l;
2281         }
2282
2283         WARN_ON(sblock->page_count == 0);
2284         if (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state)) {
2285                 /*
2286                  * This case should only be hit for RAID 5/6 device replace. See
2287                  * the comment in scrub_missing_raid56_pages() for details.
2288                  */
2289                 scrub_missing_raid56_pages(sblock);
2290         } else {
2291                 for (index = 0; index < sblock->page_count; index++) {
2292                         struct scrub_page *spage = sblock->pagev[index];
2293                         int ret;
2294
2295                         ret = scrub_add_page_to_rd_bio(sctx, spage);
2296                         if (ret) {
2297                                 scrub_block_put(sblock);
2298                                 return ret;
2299                         }
2300                 }
2301
2302                 if (force)
2303                         scrub_submit(sctx);
2304         }
2305
2306         /* last one frees, either here or in bio completion for last page */
2307         scrub_block_put(sblock);
2308         return 0;
2309 }
2310
2311 static void scrub_bio_end_io(struct bio *bio)
2312 {
2313         struct scrub_bio *sbio = bio->bi_private;
2314         struct btrfs_fs_info *fs_info = sbio->dev->fs_info;
2315
2316         sbio->status = bio->bi_status;
2317         sbio->bio = bio;
2318
2319         btrfs_queue_work(fs_info->scrub_workers, &sbio->work);
2320 }
2321
2322 static void scrub_bio_end_io_worker(struct btrfs_work *work)
2323 {
2324         struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
2325         struct scrub_ctx *sctx = sbio->sctx;
2326         int i;
2327
2328         BUG_ON(sbio->page_count > SCRUB_PAGES_PER_RD_BIO);
2329         if (sbio->status) {
2330                 for (i = 0; i < sbio->page_count; i++) {
2331                         struct scrub_page *spage = sbio->pagev[i];
2332
2333                         spage->io_error = 1;
2334                         spage->sblock->no_io_error_seen = 0;
2335                 }
2336         }
2337
2338         /* now complete the scrub_block items that have all pages completed */
2339         for (i = 0; i < sbio->page_count; i++) {
2340                 struct scrub_page *spage = sbio->pagev[i];
2341                 struct scrub_block *sblock = spage->sblock;
2342
2343                 if (atomic_dec_and_test(&sblock->outstanding_pages))
2344                         scrub_block_complete(sblock);
2345                 scrub_block_put(sblock);
2346         }
2347
2348         bio_put(sbio->bio);
2349         sbio->bio = NULL;
2350         spin_lock(&sctx->list_lock);
2351         sbio->next_free = sctx->first_free;
2352         sctx->first_free = sbio->index;
2353         spin_unlock(&sctx->list_lock);
2354
2355         if (sctx->is_dev_replace && sctx->flush_all_writes) {
2356                 mutex_lock(&sctx->wr_lock);
2357                 scrub_wr_submit(sctx);
2358                 mutex_unlock(&sctx->wr_lock);
2359         }
2360
2361         scrub_pending_bio_dec(sctx);
2362 }
2363
2364 static inline void __scrub_mark_bitmap(struct scrub_parity *sparity,
2365                                        unsigned long *bitmap,
2366                                        u64 start, u64 len)
2367 {
2368         u64 offset;
2369         u64 nsectors64;
2370         u32 nsectors;
2371         int sectorsize = sparity->sctx->fs_info->sectorsize;
2372
2373         if (len >= sparity->stripe_len) {
2374                 bitmap_set(bitmap, 0, sparity->nsectors);
2375                 return;
2376         }
2377
2378         start -= sparity->logic_start;
2379         start = div64_u64_rem(start, sparity->stripe_len, &offset);
2380         offset = div_u64(offset, sectorsize);
2381         nsectors64 = div_u64(len, sectorsize);
2382
2383         ASSERT(nsectors64 < UINT_MAX);
2384         nsectors = (u32)nsectors64;
2385
2386         if (offset + nsectors <= sparity->nsectors) {
2387                 bitmap_set(bitmap, offset, nsectors);
2388                 return;
2389         }
2390
2391         bitmap_set(bitmap, offset, sparity->nsectors - offset);
2392         bitmap_set(bitmap, 0, nsectors - (sparity->nsectors - offset));
2393 }
2394
2395 static inline void scrub_parity_mark_sectors_error(struct scrub_parity *sparity,
2396                                                    u64 start, u64 len)
2397 {
2398         __scrub_mark_bitmap(sparity, sparity->ebitmap, start, len);
2399 }
2400
2401 static inline void scrub_parity_mark_sectors_data(struct scrub_parity *sparity,
2402                                                   u64 start, u64 len)
2403 {
2404         __scrub_mark_bitmap(sparity, sparity->dbitmap, start, len);
2405 }
2406
2407 static void scrub_block_complete(struct scrub_block *sblock)
2408 {
2409         int corrupted = 0;
2410
2411         if (!sblock->no_io_error_seen) {
2412                 corrupted = 1;
2413                 scrub_handle_errored_block(sblock);
2414         } else {
2415                 /*
2416                  * if has checksum error, write via repair mechanism in
2417                  * dev replace case, otherwise write here in dev replace
2418                  * case.
2419                  */
2420                 corrupted = scrub_checksum(sblock);
2421                 if (!corrupted && sblock->sctx->is_dev_replace)
2422                         scrub_write_block_to_dev_replace(sblock);
2423         }
2424
2425         if (sblock->sparity && corrupted && !sblock->data_corrected) {
2426                 u64 start = sblock->pagev[0]->logical;
2427                 u64 end = sblock->pagev[sblock->page_count - 1]->logical +
2428                           PAGE_SIZE;
2429
2430                 scrub_parity_mark_sectors_error(sblock->sparity,
2431                                                 start, end - start);
2432         }
2433 }
2434
2435 static int scrub_find_csum(struct scrub_ctx *sctx, u64 logical, u8 *csum)
2436 {
2437         struct btrfs_ordered_sum *sum = NULL;
2438         unsigned long index;
2439         unsigned long num_sectors;
2440
2441         while (!list_empty(&sctx->csum_list)) {
2442                 sum = list_first_entry(&sctx->csum_list,
2443                                        struct btrfs_ordered_sum, list);
2444                 if (sum->bytenr > logical)
2445                         return 0;
2446                 if (sum->bytenr + sum->len > logical)
2447                         break;
2448
2449                 ++sctx->stat.csum_discards;
2450                 list_del(&sum->list);
2451                 kfree(sum);
2452                 sum = NULL;
2453         }
2454         if (!sum)
2455                 return 0;
2456
2457         index = div_u64(logical - sum->bytenr, sctx->fs_info->sectorsize);
2458         ASSERT(index < UINT_MAX);
2459
2460         num_sectors = sum->len / sctx->fs_info->sectorsize;
2461         memcpy(csum, sum->sums + index * sctx->csum_size, sctx->csum_size);
2462         if (index == num_sectors - 1) {
2463                 list_del(&sum->list);
2464                 kfree(sum);
2465         }
2466         return 1;
2467 }
2468
2469 /* scrub extent tries to collect up to 64 kB for each bio */
2470 static int scrub_extent(struct scrub_ctx *sctx, struct map_lookup *map,
2471                         u64 logical, u64 len,
2472                         u64 physical, struct btrfs_device *dev, u64 flags,
2473                         u64 gen, int mirror_num, u64 physical_for_dev_replace)
2474 {
2475         int ret;
2476         u8 csum[BTRFS_CSUM_SIZE];
2477         u32 blocksize;
2478
2479         if (flags & BTRFS_EXTENT_FLAG_DATA) {
2480                 if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
2481                         blocksize = map->stripe_len;
2482                 else
2483                         blocksize = sctx->fs_info->sectorsize;
2484                 spin_lock(&sctx->stat_lock);
2485                 sctx->stat.data_extents_scrubbed++;
2486                 sctx->stat.data_bytes_scrubbed += len;
2487                 spin_unlock(&sctx->stat_lock);
2488         } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
2489                 if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK)
2490                         blocksize = map->stripe_len;
2491                 else
2492                         blocksize = sctx->fs_info->nodesize;
2493                 spin_lock(&sctx->stat_lock);
2494                 sctx->stat.tree_extents_scrubbed++;
2495                 sctx->stat.tree_bytes_scrubbed += len;
2496                 spin_unlock(&sctx->stat_lock);
2497         } else {
2498                 blocksize = sctx->fs_info->sectorsize;
2499                 WARN_ON(1);
2500         }
2501
2502         while (len) {
2503                 u64 l = min_t(u64, len, blocksize);
2504                 int have_csum = 0;
2505
2506                 if (flags & BTRFS_EXTENT_FLAG_DATA) {
2507                         /* push csums to sbio */
2508                         have_csum = scrub_find_csum(sctx, logical, csum);
2509                         if (have_csum == 0)
2510                                 ++sctx->stat.no_csum;
2511                 }
2512                 ret = scrub_pages(sctx, logical, l, physical, dev, flags, gen,
2513                                   mirror_num, have_csum ? csum : NULL, 0,
2514                                   physical_for_dev_replace);
2515                 if (ret)
2516                         return ret;
2517                 len -= l;
2518                 logical += l;
2519                 physical += l;
2520                 physical_for_dev_replace += l;
2521         }
2522         return 0;
2523 }
2524
2525 static int scrub_pages_for_parity(struct scrub_parity *sparity,
2526                                   u64 logical, u64 len,
2527                                   u64 physical, struct btrfs_device *dev,
2528                                   u64 flags, u64 gen, int mirror_num, u8 *csum)
2529 {
2530         struct scrub_ctx *sctx = sparity->sctx;
2531         struct scrub_block *sblock;
2532         int index;
2533
2534         sblock = kzalloc(sizeof(*sblock), GFP_KERNEL);
2535         if (!sblock) {
2536                 spin_lock(&sctx->stat_lock);
2537                 sctx->stat.malloc_errors++;
2538                 spin_unlock(&sctx->stat_lock);
2539                 return -ENOMEM;
2540         }
2541
2542         /* one ref inside this function, plus one for each page added to
2543          * a bio later on */
2544         refcount_set(&sblock->refs, 1);
2545         sblock->sctx = sctx;
2546         sblock->no_io_error_seen = 1;
2547         sblock->sparity = sparity;
2548         scrub_parity_get(sparity);
2549
2550         for (index = 0; len > 0; index++) {
2551                 struct scrub_page *spage;
2552                 u64 l = min_t(u64, len, PAGE_SIZE);
2553
2554                 spage = kzalloc(sizeof(*spage), GFP_KERNEL);
2555                 if (!spage) {
2556 leave_nomem:
2557                         spin_lock(&sctx->stat_lock);
2558                         sctx->stat.malloc_errors++;
2559                         spin_unlock(&sctx->stat_lock);
2560                         scrub_block_put(sblock);
2561                         return -ENOMEM;
2562                 }
2563                 BUG_ON(index >= SCRUB_MAX_PAGES_PER_BLOCK);
2564                 /* For scrub block */
2565                 scrub_page_get(spage);
2566                 sblock->pagev[index] = spage;
2567                 /* For scrub parity */
2568                 scrub_page_get(spage);
2569                 list_add_tail(&spage->list, &sparity->spages);
2570                 spage->sblock = sblock;
2571                 spage->dev = dev;
2572                 spage->flags = flags;
2573                 spage->generation = gen;
2574                 spage->logical = logical;
2575                 spage->physical = physical;
2576                 spage->mirror_num = mirror_num;
2577                 if (csum) {
2578                         spage->have_csum = 1;
2579                         memcpy(spage->csum, csum, sctx->csum_size);
2580                 } else {
2581                         spage->have_csum = 0;
2582                 }
2583                 sblock->page_count++;
2584                 spage->page = alloc_page(GFP_KERNEL);
2585                 if (!spage->page)
2586                         goto leave_nomem;
2587                 len -= l;
2588                 logical += l;
2589                 physical += l;
2590         }
2591
2592         WARN_ON(sblock->page_count == 0);
2593         for (index = 0; index < sblock->page_count; index++) {
2594                 struct scrub_page *spage = sblock->pagev[index];
2595                 int ret;
2596
2597                 ret = scrub_add_page_to_rd_bio(sctx, spage);
2598                 if (ret) {
2599                         scrub_block_put(sblock);
2600                         return ret;
2601                 }
2602         }
2603
2604         /* last one frees, either here or in bio completion for last page */
2605         scrub_block_put(sblock);
2606         return 0;
2607 }
2608
2609 static int scrub_extent_for_parity(struct scrub_parity *sparity,
2610                                    u64 logical, u64 len,
2611                                    u64 physical, struct btrfs_device *dev,
2612                                    u64 flags, u64 gen, int mirror_num)
2613 {
2614         struct scrub_ctx *sctx = sparity->sctx;
2615         int ret;
2616         u8 csum[BTRFS_CSUM_SIZE];
2617         u32 blocksize;
2618
2619         if (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state)) {
2620                 scrub_parity_mark_sectors_error(sparity, logical, len);
2621                 return 0;
2622         }
2623
2624         if (flags & BTRFS_EXTENT_FLAG_DATA) {
2625                 blocksize = sparity->stripe_len;
2626         } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
2627                 blocksize = sparity->stripe_len;
2628         } else {
2629                 blocksize = sctx->fs_info->sectorsize;
2630                 WARN_ON(1);
2631         }
2632
2633         while (len) {
2634                 u64 l = min_t(u64, len, blocksize);
2635                 int have_csum = 0;
2636
2637                 if (flags & BTRFS_EXTENT_FLAG_DATA) {
2638                         /* push csums to sbio */
2639                         have_csum = scrub_find_csum(sctx, logical, csum);
2640                         if (have_csum == 0)
2641                                 goto skip;
2642                 }
2643                 ret = scrub_pages_for_parity(sparity, logical, l, physical, dev,
2644                                              flags, gen, mirror_num,
2645                                              have_csum ? csum : NULL);
2646                 if (ret)
2647                         return ret;
2648 skip:
2649                 len -= l;
2650                 logical += l;
2651                 physical += l;
2652         }
2653         return 0;
2654 }
2655
2656 /*
2657  * Given a physical address, this will calculate it's
2658  * logical offset. if this is a parity stripe, it will return
2659  * the most left data stripe's logical offset.
2660  *
2661  * return 0 if it is a data stripe, 1 means parity stripe.
2662  */
2663 static int get_raid56_logic_offset(u64 physical, int num,
2664                                    struct map_lookup *map, u64 *offset,
2665                                    u64 *stripe_start)
2666 {
2667         int i;
2668         int j = 0;
2669         u64 stripe_nr;
2670         u64 last_offset;
2671         u32 stripe_index;
2672         u32 rot;
2673         const int data_stripes = nr_data_stripes(map);
2674
2675         last_offset = (physical - map->stripes[num].physical) * data_stripes;
2676         if (stripe_start)
2677                 *stripe_start = last_offset;
2678
2679         *offset = last_offset;
2680         for (i = 0; i < data_stripes; i++) {
2681                 *offset = last_offset + i * map->stripe_len;
2682
2683                 stripe_nr = div64_u64(*offset, map->stripe_len);
2684                 stripe_nr = div_u64(stripe_nr, data_stripes);
2685
2686                 /* Work out the disk rotation on this stripe-set */
2687                 stripe_nr = div_u64_rem(stripe_nr, map->num_stripes, &rot);
2688                 /* calculate which stripe this data locates */
2689                 rot += i;
2690                 stripe_index = rot % map->num_stripes;
2691                 if (stripe_index == num)
2692                         return 0;
2693                 if (stripe_index < num)
2694                         j++;
2695         }
2696         *offset = last_offset + j * map->stripe_len;
2697         return 1;
2698 }
2699
2700 static void scrub_free_parity(struct scrub_parity *sparity)
2701 {
2702         struct scrub_ctx *sctx = sparity->sctx;
2703         struct scrub_page *curr, *next;
2704         int nbits;
2705
2706         nbits = bitmap_weight(sparity->ebitmap, sparity->nsectors);
2707         if (nbits) {
2708                 spin_lock(&sctx->stat_lock);
2709                 sctx->stat.read_errors += nbits;
2710                 sctx->stat.uncorrectable_errors += nbits;
2711                 spin_unlock(&sctx->stat_lock);
2712         }
2713
2714         list_for_each_entry_safe(curr, next, &sparity->spages, list) {
2715                 list_del_init(&curr->list);
2716                 scrub_page_put(curr);
2717         }
2718
2719         kfree(sparity);
2720 }
2721
2722 static void scrub_parity_bio_endio_worker(struct btrfs_work *work)
2723 {
2724         struct scrub_parity *sparity = container_of(work, struct scrub_parity,
2725                                                     work);
2726         struct scrub_ctx *sctx = sparity->sctx;
2727
2728         scrub_free_parity(sparity);
2729         scrub_pending_bio_dec(sctx);
2730 }
2731
2732 static void scrub_parity_bio_endio(struct bio *bio)
2733 {
2734         struct scrub_parity *sparity = (struct scrub_parity *)bio->bi_private;
2735         struct btrfs_fs_info *fs_info = sparity->sctx->fs_info;
2736
2737         if (bio->bi_status)
2738                 bitmap_or(sparity->ebitmap, sparity->ebitmap, sparity->dbitmap,
2739                           sparity->nsectors);
2740
2741         bio_put(bio);
2742
2743         btrfs_init_work(&sparity->work, scrub_parity_bio_endio_worker, NULL,
2744                         NULL);
2745         btrfs_queue_work(fs_info->scrub_parity_workers, &sparity->work);
2746 }
2747
2748 static void scrub_parity_check_and_repair(struct scrub_parity *sparity)
2749 {
2750         struct scrub_ctx *sctx = sparity->sctx;
2751         struct btrfs_fs_info *fs_info = sctx->fs_info;
2752         struct bio *bio;
2753         struct btrfs_raid_bio *rbio;
2754         struct btrfs_bio *bbio = NULL;
2755         u64 length;
2756         int ret;
2757
2758         if (!bitmap_andnot(sparity->dbitmap, sparity->dbitmap, sparity->ebitmap,
2759                            sparity->nsectors))
2760                 goto out;
2761
2762         length = sparity->logic_end - sparity->logic_start;
2763
2764         btrfs_bio_counter_inc_blocked(fs_info);
2765         ret = btrfs_map_sblock(fs_info, BTRFS_MAP_WRITE, sparity->logic_start,
2766                                &length, &bbio);
2767         if (ret || !bbio || !bbio->raid_map)
2768                 goto bbio_out;
2769
2770         bio = btrfs_io_bio_alloc(0);
2771         bio->bi_iter.bi_sector = sparity->logic_start >> 9;
2772         bio->bi_private = sparity;
2773         bio->bi_end_io = scrub_parity_bio_endio;
2774
2775         rbio = raid56_parity_alloc_scrub_rbio(fs_info, bio, bbio,
2776                                               length, sparity->scrub_dev,
2777                                               sparity->dbitmap,
2778                                               sparity->nsectors);
2779         if (!rbio)
2780                 goto rbio_out;
2781
2782         scrub_pending_bio_inc(sctx);
2783         raid56_parity_submit_scrub_rbio(rbio);
2784         return;
2785
2786 rbio_out:
2787         bio_put(bio);
2788 bbio_out:
2789         btrfs_bio_counter_dec(fs_info);
2790         btrfs_put_bbio(bbio);
2791         bitmap_or(sparity->ebitmap, sparity->ebitmap, sparity->dbitmap,
2792                   sparity->nsectors);
2793         spin_lock(&sctx->stat_lock);
2794         sctx->stat.malloc_errors++;
2795         spin_unlock(&sctx->stat_lock);
2796 out:
2797         scrub_free_parity(sparity);
2798 }
2799
2800 static inline int scrub_calc_parity_bitmap_len(int nsectors)
2801 {
2802         return DIV_ROUND_UP(nsectors, BITS_PER_LONG) * sizeof(long);
2803 }
2804
2805 static void scrub_parity_get(struct scrub_parity *sparity)
2806 {
2807         refcount_inc(&sparity->refs);
2808 }
2809
2810 static void scrub_parity_put(struct scrub_parity *sparity)
2811 {
2812         if (!refcount_dec_and_test(&sparity->refs))
2813                 return;
2814
2815         scrub_parity_check_and_repair(sparity);
2816 }
2817
2818 static noinline_for_stack int scrub_raid56_parity(struct scrub_ctx *sctx,
2819                                                   struct map_lookup *map,
2820                                                   struct btrfs_device *sdev,
2821                                                   struct btrfs_path *path,
2822                                                   u64 logic_start,
2823                                                   u64 logic_end)
2824 {
2825         struct btrfs_fs_info *fs_info = sctx->fs_info;
2826         struct btrfs_root *root = fs_info->extent_root;
2827         struct btrfs_root *csum_root = fs_info->csum_root;
2828         struct btrfs_extent_item *extent;
2829         struct btrfs_bio *bbio = NULL;
2830         u64 flags;
2831         int ret;
2832         int slot;
2833         struct extent_buffer *l;
2834         struct btrfs_key key;
2835         u64 generation;
2836         u64 extent_logical;
2837         u64 extent_physical;
2838         u64 extent_len;
2839         u64 mapped_length;
2840         struct btrfs_device *extent_dev;
2841         struct scrub_parity *sparity;
2842         int nsectors;
2843         int bitmap_len;
2844         int extent_mirror_num;
2845         int stop_loop = 0;
2846
2847         nsectors = div_u64(map->stripe_len, fs_info->sectorsize);
2848         bitmap_len = scrub_calc_parity_bitmap_len(nsectors);
2849         sparity = kzalloc(sizeof(struct scrub_parity) + 2 * bitmap_len,
2850                           GFP_NOFS);
2851         if (!sparity) {
2852                 spin_lock(&sctx->stat_lock);
2853                 sctx->stat.malloc_errors++;
2854                 spin_unlock(&sctx->stat_lock);
2855                 return -ENOMEM;
2856         }
2857
2858         sparity->stripe_len = map->stripe_len;
2859         sparity->nsectors = nsectors;
2860         sparity->sctx = sctx;
2861         sparity->scrub_dev = sdev;
2862         sparity->logic_start = logic_start;
2863         sparity->logic_end = logic_end;
2864         refcount_set(&sparity->refs, 1);
2865         INIT_LIST_HEAD(&sparity->spages);
2866         sparity->dbitmap = sparity->bitmap;
2867         sparity->ebitmap = (void *)sparity->bitmap + bitmap_len;
2868
2869         ret = 0;
2870         while (logic_start < logic_end) {
2871                 if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
2872                         key.type = BTRFS_METADATA_ITEM_KEY;
2873                 else
2874                         key.type = BTRFS_EXTENT_ITEM_KEY;
2875                 key.objectid = logic_start;
2876                 key.offset = (u64)-1;
2877
2878                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2879                 if (ret < 0)
2880                         goto out;
2881
2882                 if (ret > 0) {
2883                         ret = btrfs_previous_extent_item(root, path, 0);
2884                         if (ret < 0)
2885                                 goto out;
2886                         if (ret > 0) {
2887                                 btrfs_release_path(path);
2888                                 ret = btrfs_search_slot(NULL, root, &key,
2889                                                         path, 0, 0);
2890                                 if (ret < 0)
2891                                         goto out;
2892                         }
2893                 }
2894
2895                 stop_loop = 0;
2896                 while (1) {
2897                         u64 bytes;
2898
2899                         l = path->nodes[0];
2900                         slot = path->slots[0];
2901                         if (slot >= btrfs_header_nritems(l)) {
2902                                 ret = btrfs_next_leaf(root, path);
2903                                 if (ret == 0)
2904                                         continue;
2905                                 if (ret < 0)
2906                                         goto out;
2907
2908                                 stop_loop = 1;
2909                                 break;
2910                         }
2911                         btrfs_item_key_to_cpu(l, &key, slot);
2912
2913                         if (key.type != BTRFS_EXTENT_ITEM_KEY &&
2914                             key.type != BTRFS_METADATA_ITEM_KEY)
2915                                 goto next;
2916
2917                         if (key.type == BTRFS_METADATA_ITEM_KEY)
2918                                 bytes = fs_info->nodesize;
2919                         else
2920                                 bytes = key.offset;
2921
2922                         if (key.objectid + bytes <= logic_start)
2923                                 goto next;
2924
2925                         if (key.objectid >= logic_end) {
2926                                 stop_loop = 1;
2927                                 break;
2928                         }
2929
2930                         while (key.objectid >= logic_start + map->stripe_len)
2931                                 logic_start += map->stripe_len;
2932
2933                         extent = btrfs_item_ptr(l, slot,
2934                                                 struct btrfs_extent_item);
2935                         flags = btrfs_extent_flags(l, extent);
2936                         generation = btrfs_extent_generation(l, extent);
2937
2938                         if ((flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) &&
2939                             (key.objectid < logic_start ||
2940                              key.objectid + bytes >
2941                              logic_start + map->stripe_len)) {
2942                                 btrfs_err(fs_info,
2943                                           "scrub: tree block %llu spanning stripes, ignored. logical=%llu",
2944                                           key.objectid, logic_start);
2945                                 spin_lock(&sctx->stat_lock);
2946                                 sctx->stat.uncorrectable_errors++;
2947                                 spin_unlock(&sctx->stat_lock);
2948                                 goto next;
2949                         }
2950 again:
2951                         extent_logical = key.objectid;
2952                         extent_len = bytes;
2953
2954                         if (extent_logical < logic_start) {
2955                                 extent_len -= logic_start - extent_logical;
2956                                 extent_logical = logic_start;
2957                         }
2958
2959                         if (extent_logical + extent_len >
2960                             logic_start + map->stripe_len)
2961                                 extent_len = logic_start + map->stripe_len -
2962                                              extent_logical;
2963
2964                         scrub_parity_mark_sectors_data(sparity, extent_logical,
2965                                                        extent_len);
2966
2967                         mapped_length = extent_len;
2968                         bbio = NULL;
2969                         ret = btrfs_map_block(fs_info, BTRFS_MAP_READ,
2970                                         extent_logical, &mapped_length, &bbio,
2971                                         0);
2972                         if (!ret) {
2973                                 if (!bbio || mapped_length < extent_len)
2974                                         ret = -EIO;
2975                         }
2976                         if (ret) {
2977                                 btrfs_put_bbio(bbio);
2978                                 goto out;
2979                         }
2980                         extent_physical = bbio->stripes[0].physical;
2981                         extent_mirror_num = bbio->mirror_num;
2982                         extent_dev = bbio->stripes[0].dev;
2983                         btrfs_put_bbio(bbio);
2984
2985                         ret = btrfs_lookup_csums_range(csum_root,
2986                                                 extent_logical,
2987                                                 extent_logical + extent_len - 1,
2988                                                 &sctx->csum_list, 1);
2989                         if (ret)
2990                                 goto out;
2991
2992                         ret = scrub_extent_for_parity(sparity, extent_logical,
2993                                                       extent_len,
2994                                                       extent_physical,
2995                                                       extent_dev, flags,
2996                                                       generation,
2997                                                       extent_mirror_num);
2998
2999                         scrub_free_csums(sctx);
3000
3001                         if (ret)
3002                                 goto out;
3003
3004                         if (extent_logical + extent_len <
3005                             key.objectid + bytes) {
3006                                 logic_start += map->stripe_len;
3007
3008                                 if (logic_start >= logic_end) {
3009                                         stop_loop = 1;
3010                                         break;
3011                                 }
3012
3013                                 if (logic_start < key.objectid + bytes) {
3014                                         cond_resched();
3015                                         goto again;
3016                                 }
3017                         }
3018 next:
3019                         path->slots[0]++;
3020                 }
3021
3022                 btrfs_release_path(path);
3023
3024                 if (stop_loop)
3025                         break;
3026
3027                 logic_start += map->stripe_len;
3028         }
3029 out:
3030         if (ret < 0)
3031                 scrub_parity_mark_sectors_error(sparity, logic_start,
3032                                                 logic_end - logic_start);
3033         scrub_parity_put(sparity);
3034         scrub_submit(sctx);
3035         mutex_lock(&sctx->wr_lock);
3036         scrub_wr_submit(sctx);
3037         mutex_unlock(&sctx->wr_lock);
3038
3039         btrfs_release_path(path);
3040         return ret < 0 ? ret : 0;
3041 }
3042
3043 static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
3044                                            struct map_lookup *map,
3045                                            struct btrfs_device *scrub_dev,
3046                                            int num, u64 base, u64 length)
3047 {
3048         struct btrfs_path *path, *ppath;
3049         struct btrfs_fs_info *fs_info = sctx->fs_info;
3050         struct btrfs_root *root = fs_info->extent_root;
3051         struct btrfs_root *csum_root = fs_info->csum_root;
3052         struct btrfs_extent_item *extent;
3053         struct blk_plug plug;
3054         u64 flags;
3055         int ret;
3056         int slot;
3057         u64 nstripes;
3058         struct extent_buffer *l;
3059         u64 physical;
3060         u64 logical;
3061         u64 logic_end;
3062         u64 physical_end;
3063         u64 generation;
3064         int mirror_num;
3065         struct reada_control *reada1;
3066         struct reada_control *reada2;
3067         struct btrfs_key key;
3068         struct btrfs_key key_end;
3069         u64 increment = map->stripe_len;
3070         u64 offset;
3071         u64 extent_logical;
3072         u64 extent_physical;
3073         u64 extent_len;
3074         u64 stripe_logical;
3075         u64 stripe_end;
3076         struct btrfs_device *extent_dev;
3077         int extent_mirror_num;
3078         int stop_loop = 0;
3079
3080         physical = map->stripes[num].physical;
3081         offset = 0;
3082         nstripes = div64_u64(length, map->stripe_len);
3083         if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
3084                 offset = map->stripe_len * num;
3085                 increment = map->stripe_len * map->num_stripes;
3086                 mirror_num = 1;
3087         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
3088                 int factor = map->num_stripes / map->sub_stripes;
3089                 offset = map->stripe_len * (num / map->sub_stripes);
3090                 increment = map->stripe_len * factor;
3091                 mirror_num = num % map->sub_stripes + 1;
3092         } else if (map->type & BTRFS_BLOCK_GROUP_RAID1_MASK) {
3093                 increment = map->stripe_len;
3094                 mirror_num = num % map->num_stripes + 1;
3095         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
3096                 increment = map->stripe_len;
3097                 mirror_num = num % map->num_stripes + 1;
3098         } else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
3099                 get_raid56_logic_offset(physical, num, map, &offset, NULL);
3100                 increment = map->stripe_len * nr_data_stripes(map);
3101                 mirror_num = 1;
3102         } else {
3103                 increment = map->stripe_len;
3104                 mirror_num = 1;
3105         }
3106
3107         path = btrfs_alloc_path();
3108         if (!path)
3109                 return -ENOMEM;
3110
3111         ppath = btrfs_alloc_path();
3112         if (!ppath) {
3113                 btrfs_free_path(path);
3114                 return -ENOMEM;
3115         }
3116
3117         /*
3118          * work on commit root. The related disk blocks are static as
3119          * long as COW is applied. This means, it is save to rewrite
3120          * them to repair disk errors without any race conditions
3121          */
3122         path->search_commit_root = 1;
3123         path->skip_locking = 1;
3124
3125         ppath->search_commit_root = 1;
3126         ppath->skip_locking = 1;
3127         /*
3128          * trigger the readahead for extent tree csum tree and wait for
3129          * completion. During readahead, the scrub is officially paused
3130          * to not hold off transaction commits
3131          */
3132         logical = base + offset;
3133         physical_end = physical + nstripes * map->stripe_len;
3134         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
3135                 get_raid56_logic_offset(physical_end, num,
3136                                         map, &logic_end, NULL);
3137                 logic_end += base;
3138         } else {
3139                 logic_end = logical + increment * nstripes;
3140         }
3141         wait_event(sctx->list_wait,
3142                    atomic_read(&sctx->bios_in_flight) == 0);
3143         scrub_blocked_if_needed(fs_info);
3144
3145         /* FIXME it might be better to start readahead at commit root */
3146         key.objectid = logical;
3147         key.type = BTRFS_EXTENT_ITEM_KEY;
3148         key.offset = (u64)0;
3149         key_end.objectid = logic_end;
3150         key_end.type = BTRFS_METADATA_ITEM_KEY;
3151         key_end.offset = (u64)-1;
3152         reada1 = btrfs_reada_add(root, &key, &key_end);
3153
3154         key.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
3155         key.type = BTRFS_EXTENT_CSUM_KEY;
3156         key.offset = logical;
3157         key_end.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
3158         key_end.type = BTRFS_EXTENT_CSUM_KEY;
3159         key_end.offset = logic_end;
3160         reada2 = btrfs_reada_add(csum_root, &key, &key_end);
3161
3162         if (!IS_ERR(reada1))
3163                 btrfs_reada_wait(reada1);
3164         if (!IS_ERR(reada2))
3165                 btrfs_reada_wait(reada2);
3166
3167
3168         /*
3169          * collect all data csums for the stripe to avoid seeking during
3170          * the scrub. This might currently (crc32) end up to be about 1MB
3171          */
3172         blk_start_plug(&plug);
3173
3174         /*
3175          * now find all extents for each stripe and scrub them
3176          */
3177         ret = 0;
3178         while (physical < physical_end) {
3179                 /*
3180                  * canceled?
3181                  */
3182                 if (atomic_read(&fs_info->scrub_cancel_req) ||
3183                     atomic_read(&sctx->cancel_req)) {
3184                         ret = -ECANCELED;
3185                         goto out;
3186                 }
3187                 /*
3188                  * check to see if we have to pause
3189                  */
3190                 if (atomic_read(&fs_info->scrub_pause_req)) {
3191                         /* push queued extents */
3192                         sctx->flush_all_writes = true;
3193                         scrub_submit(sctx);
3194                         mutex_lock(&sctx->wr_lock);
3195                         scrub_wr_submit(sctx);
3196                         mutex_unlock(&sctx->wr_lock);
3197                         wait_event(sctx->list_wait,
3198                                    atomic_read(&sctx->bios_in_flight) == 0);
3199                         sctx->flush_all_writes = false;
3200                         scrub_blocked_if_needed(fs_info);
3201                 }
3202
3203                 if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
3204                         ret = get_raid56_logic_offset(physical, num, map,
3205                                                       &logical,
3206                                                       &stripe_logical);
3207                         logical += base;
3208                         if (ret) {
3209                                 /* it is parity strip */
3210                                 stripe_logical += base;
3211                                 stripe_end = stripe_logical + increment;
3212                                 ret = scrub_raid56_parity(sctx, map, scrub_dev,
3213                                                           ppath, stripe_logical,
3214                                                           stripe_end);
3215                                 if (ret)
3216                                         goto out;
3217                                 goto skip;
3218                         }
3219                 }
3220
3221                 if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
3222                         key.type = BTRFS_METADATA_ITEM_KEY;
3223                 else
3224                         key.type = BTRFS_EXTENT_ITEM_KEY;
3225                 key.objectid = logical;
3226                 key.offset = (u64)-1;
3227
3228                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3229                 if (ret < 0)
3230                         goto out;
3231
3232                 if (ret > 0) {
3233                         ret = btrfs_previous_extent_item(root, path, 0);
3234                         if (ret < 0)
3235                                 goto out;
3236                         if (ret > 0) {
3237                                 /* there's no smaller item, so stick with the
3238                                  * larger one */
3239                                 btrfs_release_path(path);
3240                                 ret = btrfs_search_slot(NULL, root, &key,
3241                                                         path, 0, 0);
3242                                 if (ret < 0)
3243                                         goto out;
3244                         }
3245                 }
3246
3247                 stop_loop = 0;
3248                 while (1) {
3249                         u64 bytes;
3250
3251                         l = path->nodes[0];
3252                         slot = path->slots[0];
3253                         if (slot >= btrfs_header_nritems(l)) {
3254                                 ret = btrfs_next_leaf(root, path);
3255                                 if (ret == 0)
3256                                         continue;
3257                                 if (ret < 0)
3258                                         goto out;
3259
3260                                 stop_loop = 1;
3261                                 break;
3262                         }
3263                         btrfs_item_key_to_cpu(l, &key, slot);
3264
3265                         if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3266                             key.type != BTRFS_METADATA_ITEM_KEY)
3267                                 goto next;
3268
3269                         if (key.type == BTRFS_METADATA_ITEM_KEY)
3270                                 bytes = fs_info->nodesize;
3271                         else
3272                                 bytes = key.offset;
3273
3274                         if (key.objectid + bytes <= logical)
3275                                 goto next;
3276
3277                         if (key.objectid >= logical + map->stripe_len) {
3278                                 /* out of this device extent */
3279                                 if (key.objectid >= logic_end)
3280                                         stop_loop = 1;
3281                                 break;
3282                         }
3283
3284                         extent = btrfs_item_ptr(l, slot,
3285                                                 struct btrfs_extent_item);
3286                         flags = btrfs_extent_flags(l, extent);
3287                         generation = btrfs_extent_generation(l, extent);
3288
3289                         if ((flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) &&
3290                             (key.objectid < logical ||
3291                              key.objectid + bytes >
3292                              logical + map->stripe_len)) {
3293                                 btrfs_err(fs_info,
3294                                            "scrub: tree block %llu spanning stripes, ignored. logical=%llu",
3295                                        key.objectid, logical);
3296                                 spin_lock(&sctx->stat_lock);
3297                                 sctx->stat.uncorrectable_errors++;
3298                                 spin_unlock(&sctx->stat_lock);
3299                                 goto next;
3300                         }
3301
3302 again:
3303                         extent_logical = key.objectid;
3304                         extent_len = bytes;
3305
3306                         /*
3307                          * trim extent to this stripe
3308                          */
3309                         if (extent_logical < logical) {
3310                                 extent_len -= logical - extent_logical;
3311                                 extent_logical = logical;
3312                         }
3313                         if (extent_logical + extent_len >
3314                             logical + map->stripe_len) {
3315                                 extent_len = logical + map->stripe_len -
3316                                              extent_logical;
3317                         }
3318
3319                         extent_physical = extent_logical - logical + physical;
3320                         extent_dev = scrub_dev;
3321                         extent_mirror_num = mirror_num;
3322                         if (sctx->is_dev_replace)
3323                                 scrub_remap_extent(fs_info, extent_logical,
3324                                                    extent_len, &extent_physical,
3325                                                    &extent_dev,
3326                                                    &extent_mirror_num);
3327
3328                         ret = btrfs_lookup_csums_range(csum_root,
3329                                                        extent_logical,
3330                                                        extent_logical +
3331                                                        extent_len - 1,
3332                                                        &sctx->csum_list, 1);
3333                         if (ret)
3334                                 goto out;
3335
3336                         ret = scrub_extent(sctx, map, extent_logical, extent_len,
3337                                            extent_physical, extent_dev, flags,
3338                                            generation, extent_mirror_num,
3339                                            extent_logical - logical + physical);
3340
3341                         scrub_free_csums(sctx);
3342
3343                         if (ret)
3344                                 goto out;
3345
3346                         if (extent_logical + extent_len <
3347                             key.objectid + bytes) {
3348                                 if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
3349                                         /*
3350                                          * loop until we find next data stripe
3351                                          * or we have finished all stripes.
3352                                          */
3353 loop:
3354                                         physical += map->stripe_len;
3355                                         ret = get_raid56_logic_offset(physical,
3356                                                         num, map, &logical,
3357                                                         &stripe_logical);
3358                                         logical += base;
3359
3360                                         if (ret && physical < physical_end) {
3361                                                 stripe_logical += base;
3362                                                 stripe_end = stripe_logical +
3363                                                                 increment;
3364                                                 ret = scrub_raid56_parity(sctx,
3365                                                         map, scrub_dev, ppath,
3366                                                         stripe_logical,
3367                                                         stripe_end);
3368                                                 if (ret)
3369                                                         goto out;
3370                                                 goto loop;
3371                                         }
3372                                 } else {
3373                                         physical += map->stripe_len;
3374                                         logical += increment;
3375                                 }
3376                                 if (logical < key.objectid + bytes) {
3377                                         cond_resched();
3378                                         goto again;
3379                                 }
3380
3381                                 if (physical >= physical_end) {
3382                                         stop_loop = 1;
3383                                         break;
3384                                 }
3385                         }
3386 next:
3387                         path->slots[0]++;
3388                 }
3389                 btrfs_release_path(path);
3390 skip:
3391                 logical += increment;
3392                 physical += map->stripe_len;
3393                 spin_lock(&sctx->stat_lock);
3394                 if (stop_loop)
3395                         sctx->stat.last_physical = map->stripes[num].physical +
3396                                                    length;
3397                 else
3398                         sctx->stat.last_physical = physical;
3399                 spin_unlock(&sctx->stat_lock);
3400                 if (stop_loop)
3401                         break;
3402         }
3403 out:
3404         /* push queued extents */
3405         scrub_submit(sctx);
3406         mutex_lock(&sctx->wr_lock);
3407         scrub_wr_submit(sctx);
3408         mutex_unlock(&sctx->wr_lock);
3409
3410         blk_finish_plug(&plug);
3411         btrfs_free_path(path);
3412         btrfs_free_path(ppath);
3413         return ret < 0 ? ret : 0;
3414 }
3415
3416 static noinline_for_stack int scrub_chunk(struct scrub_ctx *sctx,
3417                                           struct btrfs_device *scrub_dev,
3418                                           u64 chunk_offset, u64 length,
3419                                           u64 dev_offset,
3420                                           struct btrfs_block_group *cache)
3421 {
3422         struct btrfs_fs_info *fs_info = sctx->fs_info;
3423         struct extent_map_tree *map_tree = &fs_info->mapping_tree;
3424         struct map_lookup *map;
3425         struct extent_map *em;
3426         int i;
3427         int ret = 0;
3428
3429         read_lock(&map_tree->lock);
3430         em = lookup_extent_mapping(map_tree, chunk_offset, 1);
3431         read_unlock(&map_tree->lock);
3432
3433         if (!em) {
3434                 /*
3435                  * Might have been an unused block group deleted by the cleaner
3436                  * kthread or relocation.
3437                  */
3438                 spin_lock(&cache->lock);
3439                 if (!cache->removed)
3440                         ret = -EINVAL;
3441                 spin_unlock(&cache->lock);
3442
3443                 return ret;
3444         }
3445
3446         map = em->map_lookup;
3447         if (em->start != chunk_offset)
3448                 goto out;
3449
3450         if (em->len < length)
3451                 goto out;
3452
3453         for (i = 0; i < map->num_stripes; ++i) {
3454                 if (map->stripes[i].dev->bdev == scrub_dev->bdev &&
3455                     map->stripes[i].physical == dev_offset) {
3456                         ret = scrub_stripe(sctx, map, scrub_dev, i,
3457                                            chunk_offset, length);
3458                         if (ret)
3459                                 goto out;
3460                 }
3461         }
3462 out:
3463         free_extent_map(em);
3464
3465         return ret;
3466 }
3467
3468 static noinline_for_stack
3469 int scrub_enumerate_chunks(struct scrub_ctx *sctx,
3470                            struct btrfs_device *scrub_dev, u64 start, u64 end)
3471 {
3472         struct btrfs_dev_extent *dev_extent = NULL;
3473         struct btrfs_path *path;
3474         struct btrfs_fs_info *fs_info = sctx->fs_info;
3475         struct btrfs_root *root = fs_info->dev_root;
3476         u64 length;
3477         u64 chunk_offset;
3478         int ret = 0;
3479         int ro_set;
3480         int slot;
3481         struct extent_buffer *l;
3482         struct btrfs_key key;
3483         struct btrfs_key found_key;
3484         struct btrfs_block_group *cache;
3485         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
3486
3487         path = btrfs_alloc_path();
3488         if (!path)
3489                 return -ENOMEM;
3490
3491         path->reada = READA_FORWARD;
3492         path->search_commit_root = 1;
3493         path->skip_locking = 1;
3494
3495         key.objectid = scrub_dev->devid;
3496         key.offset = 0ull;
3497         key.type = BTRFS_DEV_EXTENT_KEY;
3498
3499         while (1) {
3500                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3501                 if (ret < 0)
3502                         break;
3503                 if (ret > 0) {
3504                         if (path->slots[0] >=
3505                             btrfs_header_nritems(path->nodes[0])) {
3506                                 ret = btrfs_next_leaf(root, path);
3507                                 if (ret < 0)
3508                                         break;
3509                                 if (ret > 0) {
3510                                         ret = 0;
3511                                         break;
3512                                 }
3513                         } else {
3514                                 ret = 0;
3515                         }
3516                 }
3517
3518                 l = path->nodes[0];
3519                 slot = path->slots[0];
3520
3521                 btrfs_item_key_to_cpu(l, &found_key, slot);
3522
3523                 if (found_key.objectid != scrub_dev->devid)
3524                         break;
3525
3526                 if (found_key.type != BTRFS_DEV_EXTENT_KEY)
3527                         break;
3528
3529                 if (found_key.offset >= end)
3530                         break;
3531
3532                 if (found_key.offset < key.offset)
3533                         break;
3534
3535                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
3536                 length = btrfs_dev_extent_length(l, dev_extent);
3537
3538                 if (found_key.offset + length <= start)
3539                         goto skip;
3540
3541                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
3542
3543                 /*
3544                  * get a reference on the corresponding block group to prevent
3545                  * the chunk from going away while we scrub it
3546                  */
3547                 cache = btrfs_lookup_block_group(fs_info, chunk_offset);
3548
3549                 /* some chunks are removed but not committed to disk yet,
3550                  * continue scrubbing */
3551                 if (!cache)
3552                         goto skip;
3553
3554                 /*
3555                  * we need call btrfs_inc_block_group_ro() with scrubs_paused,
3556                  * to avoid deadlock caused by:
3557                  * btrfs_inc_block_group_ro()
3558                  * -> btrfs_wait_for_commit()
3559                  * -> btrfs_commit_transaction()
3560                  * -> btrfs_scrub_pause()
3561                  */
3562                 scrub_pause_on(fs_info);
3563
3564                 /*
3565                  * Don't do chunk preallocation for scrub.
3566                  *
3567                  * This is especially important for SYSTEM bgs, or we can hit
3568                  * -EFBIG from btrfs_finish_chunk_alloc() like:
3569                  * 1. The only SYSTEM bg is marked RO.
3570                  *    Since SYSTEM bg is small, that's pretty common.
3571                  * 2. New SYSTEM bg will be allocated
3572                  *    Due to regular version will allocate new chunk.
3573                  * 3. New SYSTEM bg is empty and will get cleaned up
3574                  *    Before cleanup really happens, it's marked RO again.
3575                  * 4. Empty SYSTEM bg get scrubbed
3576                  *    We go back to 2.
3577                  *
3578                  * This can easily boost the amount of SYSTEM chunks if cleaner
3579                  * thread can't be triggered fast enough, and use up all space
3580                  * of btrfs_super_block::sys_chunk_array
3581                  *
3582                  * While for dev replace, we need to try our best to mark block
3583                  * group RO, to prevent race between:
3584                  * - Write duplication
3585                  *   Contains latest data
3586                  * - Scrub copy
3587                  *   Contains data from commit tree
3588                  *
3589                  * If target block group is not marked RO, nocow writes can
3590                  * be overwritten by scrub copy, causing data corruption.
3591                  * So for dev-replace, it's not allowed to continue if a block
3592                  * group is not RO.
3593                  */
3594                 ret = btrfs_inc_block_group_ro(cache, sctx->is_dev_replace);
3595                 if (ret == 0) {
3596                         ro_set = 1;
3597                 } else if (ret == -ENOSPC && !sctx->is_dev_replace) {
3598                         /*
3599                          * btrfs_inc_block_group_ro return -ENOSPC when it
3600                          * failed in creating new chunk for metadata.
3601                          * It is not a problem for scrub, because
3602                          * metadata are always cowed, and our scrub paused
3603                          * commit_transactions.
3604                          */
3605                         ro_set = 0;
3606                 } else {
3607                         btrfs_warn(fs_info,
3608                                    "failed setting block group ro: %d", ret);
3609                         btrfs_put_block_group(cache);
3610                         scrub_pause_off(fs_info);
3611                         break;
3612                 }
3613
3614                 /*
3615                  * Now the target block is marked RO, wait for nocow writes to
3616                  * finish before dev-replace.
3617                  * COW is fine, as COW never overwrites extents in commit tree.
3618                  */
3619                 if (sctx->is_dev_replace) {
3620                         btrfs_wait_nocow_writers(cache);
3621                         btrfs_wait_ordered_roots(fs_info, U64_MAX, cache->start,
3622                                         cache->length);
3623                 }
3624
3625                 scrub_pause_off(fs_info);
3626                 down_write(&dev_replace->rwsem);
3627                 dev_replace->cursor_right = found_key.offset + length;
3628                 dev_replace->cursor_left = found_key.offset;
3629                 dev_replace->item_needs_writeback = 1;
3630                 up_write(&dev_replace->rwsem);
3631
3632                 ret = scrub_chunk(sctx, scrub_dev, chunk_offset, length,
3633                                   found_key.offset, cache);
3634
3635                 /*
3636                  * flush, submit all pending read and write bios, afterwards
3637                  * wait for them.
3638                  * Note that in the dev replace case, a read request causes
3639                  * write requests that are submitted in the read completion
3640                  * worker. Therefore in the current situation, it is required
3641                  * that all write requests are flushed, so that all read and
3642                  * write requests are really completed when bios_in_flight
3643                  * changes to 0.
3644                  */
3645                 sctx->flush_all_writes = true;
3646                 scrub_submit(sctx);
3647                 mutex_lock(&sctx->wr_lock);
3648                 scrub_wr_submit(sctx);
3649                 mutex_unlock(&sctx->wr_lock);
3650
3651                 wait_event(sctx->list_wait,
3652                            atomic_read(&sctx->bios_in_flight) == 0);
3653
3654                 scrub_pause_on(fs_info);
3655
3656                 /*
3657                  * must be called before we decrease @scrub_paused.
3658                  * make sure we don't block transaction commit while
3659                  * we are waiting pending workers finished.
3660                  */
3661                 wait_event(sctx->list_wait,
3662                            atomic_read(&sctx->workers_pending) == 0);
3663                 sctx->flush_all_writes = false;
3664
3665                 scrub_pause_off(fs_info);
3666
3667                 down_write(&dev_replace->rwsem);
3668                 dev_replace->cursor_left = dev_replace->cursor_right;
3669                 dev_replace->item_needs_writeback = 1;
3670                 up_write(&dev_replace->rwsem);
3671
3672                 if (ro_set)
3673                         btrfs_dec_block_group_ro(cache);
3674
3675                 /*
3676                  * We might have prevented the cleaner kthread from deleting
3677                  * this block group if it was already unused because we raced
3678                  * and set it to RO mode first. So add it back to the unused
3679                  * list, otherwise it might not ever be deleted unless a manual
3680                  * balance is triggered or it becomes used and unused again.
3681                  */
3682                 spin_lock(&cache->lock);
3683                 if (!cache->removed && !cache->ro && cache->reserved == 0 &&
3684                     cache->used == 0) {
3685                         spin_unlock(&cache->lock);
3686                         if (btrfs_test_opt(fs_info, DISCARD_ASYNC))
3687                                 btrfs_discard_queue_work(&fs_info->discard_ctl,
3688                                                          cache);
3689                         else
3690                                 btrfs_mark_bg_unused(cache);
3691                 } else {
3692                         spin_unlock(&cache->lock);
3693                 }
3694
3695                 btrfs_put_block_group(cache);
3696                 if (ret)
3697                         break;
3698                 if (sctx->is_dev_replace &&
3699                     atomic64_read(&dev_replace->num_write_errors) > 0) {
3700                         ret = -EIO;
3701                         break;
3702                 }
3703                 if (sctx->stat.malloc_errors > 0) {
3704                         ret = -ENOMEM;
3705                         break;
3706                 }
3707 skip:
3708                 key.offset = found_key.offset + length;
3709                 btrfs_release_path(path);
3710         }
3711
3712         btrfs_free_path(path);
3713
3714         return ret;
3715 }
3716
3717 static noinline_for_stack int scrub_supers(struct scrub_ctx *sctx,
3718                                            struct btrfs_device *scrub_dev)
3719 {
3720         int     i;
3721         u64     bytenr;
3722         u64     gen;
3723         int     ret;
3724         struct btrfs_fs_info *fs_info = sctx->fs_info;
3725
3726         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
3727                 return -EIO;
3728
3729         /* Seed devices of a new filesystem has their own generation. */
3730         if (scrub_dev->fs_devices != fs_info->fs_devices)
3731                 gen = scrub_dev->generation;
3732         else
3733                 gen = fs_info->last_trans_committed;
3734
3735         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
3736                 bytenr = btrfs_sb_offset(i);
3737                 if (bytenr + BTRFS_SUPER_INFO_SIZE >
3738                     scrub_dev->commit_total_bytes)
3739                         break;
3740
3741                 ret = scrub_pages(sctx, bytenr, BTRFS_SUPER_INFO_SIZE, bytenr,
3742                                   scrub_dev, BTRFS_EXTENT_FLAG_SUPER, gen, i,
3743                                   NULL, 1, bytenr);
3744                 if (ret)
3745                         return ret;
3746         }
3747         wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0);
3748
3749         return 0;
3750 }
3751
3752 /*
3753  * get a reference count on fs_info->scrub_workers. start worker if necessary
3754  */
3755 static noinline_for_stack int scrub_workers_get(struct btrfs_fs_info *fs_info,
3756                                                 int is_dev_replace)
3757 {
3758         unsigned int flags = WQ_FREEZABLE | WQ_UNBOUND;
3759         int max_active = fs_info->thread_pool_size;
3760
3761         lockdep_assert_held(&fs_info->scrub_lock);
3762
3763         if (refcount_read(&fs_info->scrub_workers_refcnt) == 0) {
3764                 ASSERT(fs_info->scrub_workers == NULL);
3765                 fs_info->scrub_workers = btrfs_alloc_workqueue(fs_info, "scrub",
3766                                 flags, is_dev_replace ? 1 : max_active, 4);
3767                 if (!fs_info->scrub_workers)
3768                         goto fail_scrub_workers;
3769
3770                 ASSERT(fs_info->scrub_wr_completion_workers == NULL);
3771                 fs_info->scrub_wr_completion_workers =
3772                         btrfs_alloc_workqueue(fs_info, "scrubwrc", flags,
3773                                               max_active, 2);
3774                 if (!fs_info->scrub_wr_completion_workers)
3775                         goto fail_scrub_wr_completion_workers;
3776
3777                 ASSERT(fs_info->scrub_parity_workers == NULL);
3778                 fs_info->scrub_parity_workers =
3779                         btrfs_alloc_workqueue(fs_info, "scrubparity", flags,
3780                                               max_active, 2);
3781                 if (!fs_info->scrub_parity_workers)
3782                         goto fail_scrub_parity_workers;
3783
3784                 refcount_set(&fs_info->scrub_workers_refcnt, 1);
3785         } else {
3786                 refcount_inc(&fs_info->scrub_workers_refcnt);
3787         }
3788         return 0;
3789
3790 fail_scrub_parity_workers:
3791         btrfs_destroy_workqueue(fs_info->scrub_wr_completion_workers);
3792 fail_scrub_wr_completion_workers:
3793         btrfs_destroy_workqueue(fs_info->scrub_workers);
3794 fail_scrub_workers:
3795         return -ENOMEM;
3796 }
3797
3798 int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
3799                     u64 end, struct btrfs_scrub_progress *progress,
3800                     int readonly, int is_dev_replace)
3801 {
3802         struct scrub_ctx *sctx;
3803         int ret;
3804         struct btrfs_device *dev;
3805         unsigned int nofs_flag;
3806         struct btrfs_workqueue *scrub_workers = NULL;
3807         struct btrfs_workqueue *scrub_wr_comp = NULL;
3808         struct btrfs_workqueue *scrub_parity = NULL;
3809
3810         if (btrfs_fs_closing(fs_info))
3811                 return -EAGAIN;
3812
3813         if (fs_info->nodesize > BTRFS_STRIPE_LEN) {
3814                 /*
3815                  * in this case scrub is unable to calculate the checksum
3816                  * the way scrub is implemented. Do not handle this
3817                  * situation at all because it won't ever happen.
3818                  */
3819                 btrfs_err(fs_info,
3820                            "scrub: size assumption nodesize <= BTRFS_STRIPE_LEN (%d <= %d) fails",
3821                        fs_info->nodesize,
3822                        BTRFS_STRIPE_LEN);
3823                 return -EINVAL;
3824         }
3825
3826         if (fs_info->sectorsize != PAGE_SIZE) {
3827                 /* not supported for data w/o checksums */
3828                 btrfs_err_rl(fs_info,
3829                            "scrub: size assumption sectorsize != PAGE_SIZE (%d != %lu) fails",
3830                        fs_info->sectorsize, PAGE_SIZE);
3831                 return -EINVAL;
3832         }
3833
3834         if (fs_info->nodesize >
3835             PAGE_SIZE * SCRUB_MAX_PAGES_PER_BLOCK ||
3836             fs_info->sectorsize > PAGE_SIZE * SCRUB_MAX_PAGES_PER_BLOCK) {
3837                 /*
3838                  * would exhaust the array bounds of pagev member in
3839                  * struct scrub_block
3840                  */
3841                 btrfs_err(fs_info,
3842                           "scrub: size assumption nodesize and sectorsize <= SCRUB_MAX_PAGES_PER_BLOCK (%d <= %d && %d <= %d) fails",
3843                        fs_info->nodesize,
3844                        SCRUB_MAX_PAGES_PER_BLOCK,
3845                        fs_info->sectorsize,
3846                        SCRUB_MAX_PAGES_PER_BLOCK);
3847                 return -EINVAL;
3848         }
3849
3850         /* Allocate outside of device_list_mutex */
3851         sctx = scrub_setup_ctx(fs_info, is_dev_replace);
3852         if (IS_ERR(sctx))
3853                 return PTR_ERR(sctx);
3854
3855         mutex_lock(&fs_info->fs_devices->device_list_mutex);
3856         dev = btrfs_find_device(fs_info->fs_devices, devid, NULL, NULL, true);
3857         if (!dev || (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state) &&
3858                      !is_dev_replace)) {
3859                 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3860                 ret = -ENODEV;
3861                 goto out_free_ctx;
3862         }
3863
3864         if (!is_dev_replace && !readonly &&
3865             !test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state)) {
3866                 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3867                 btrfs_err_in_rcu(fs_info, "scrub: device %s is not writable",
3868                                 rcu_str_deref(dev->name));
3869                 ret = -EROFS;
3870                 goto out_free_ctx;
3871         }
3872
3873         mutex_lock(&fs_info->scrub_lock);
3874         if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &dev->dev_state) ||
3875             test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &dev->dev_state)) {
3876                 mutex_unlock(&fs_info->scrub_lock);
3877                 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3878                 ret = -EIO;
3879                 goto out_free_ctx;
3880         }
3881
3882         down_read(&fs_info->dev_replace.rwsem);
3883         if (dev->scrub_ctx ||
3884             (!is_dev_replace &&
3885              btrfs_dev_replace_is_ongoing(&fs_info->dev_replace))) {
3886                 up_read(&fs_info->dev_replace.rwsem);
3887                 mutex_unlock(&fs_info->scrub_lock);
3888                 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3889                 ret = -EINPROGRESS;
3890                 goto out_free_ctx;
3891         }
3892         up_read(&fs_info->dev_replace.rwsem);
3893
3894         ret = scrub_workers_get(fs_info, is_dev_replace);
3895         if (ret) {
3896                 mutex_unlock(&fs_info->scrub_lock);
3897                 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3898                 goto out_free_ctx;
3899         }
3900
3901         sctx->readonly = readonly;
3902         dev->scrub_ctx = sctx;
3903         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3904
3905         /*
3906          * checking @scrub_pause_req here, we can avoid
3907          * race between committing transaction and scrubbing.
3908          */
3909         __scrub_blocked_if_needed(fs_info);
3910         atomic_inc(&fs_info->scrubs_running);
3911         mutex_unlock(&fs_info->scrub_lock);
3912
3913         /*
3914          * In order to avoid deadlock with reclaim when there is a transaction
3915          * trying to pause scrub, make sure we use GFP_NOFS for all the
3916          * allocations done at btrfs_scrub_pages() and scrub_pages_for_parity()
3917          * invoked by our callees. The pausing request is done when the
3918          * transaction commit starts, and it blocks the transaction until scrub
3919          * is paused (done at specific points at scrub_stripe() or right above
3920          * before incrementing fs_info->scrubs_running).
3921          */
3922         nofs_flag = memalloc_nofs_save();
3923         if (!is_dev_replace) {
3924                 btrfs_info(fs_info, "scrub: started on devid %llu", devid);
3925                 /*
3926                  * by holding device list mutex, we can
3927                  * kick off writing super in log tree sync.
3928                  */
3929                 mutex_lock(&fs_info->fs_devices->device_list_mutex);
3930                 ret = scrub_supers(sctx, dev);
3931                 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3932         }
3933
3934         if (!ret)
3935                 ret = scrub_enumerate_chunks(sctx, dev, start, end);
3936         memalloc_nofs_restore(nofs_flag);
3937
3938         wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0);
3939         atomic_dec(&fs_info->scrubs_running);
3940         wake_up(&fs_info->scrub_pause_wait);
3941
3942         wait_event(sctx->list_wait, atomic_read(&sctx->workers_pending) == 0);
3943
3944         if (progress)
3945                 memcpy(progress, &sctx->stat, sizeof(*progress));
3946
3947         if (!is_dev_replace)
3948                 btrfs_info(fs_info, "scrub: %s on devid %llu with status: %d",
3949                         ret ? "not finished" : "finished", devid, ret);
3950
3951         mutex_lock(&fs_info->scrub_lock);
3952         dev->scrub_ctx = NULL;
3953         if (refcount_dec_and_test(&fs_info->scrub_workers_refcnt)) {
3954                 scrub_workers = fs_info->scrub_workers;
3955                 scrub_wr_comp = fs_info->scrub_wr_completion_workers;
3956                 scrub_parity = fs_info->scrub_parity_workers;
3957
3958                 fs_info->scrub_workers = NULL;
3959                 fs_info->scrub_wr_completion_workers = NULL;
3960                 fs_info->scrub_parity_workers = NULL;
3961         }
3962         mutex_unlock(&fs_info->scrub_lock);
3963
3964         btrfs_destroy_workqueue(scrub_workers);
3965         btrfs_destroy_workqueue(scrub_wr_comp);
3966         btrfs_destroy_workqueue(scrub_parity);
3967         scrub_put_ctx(sctx);
3968
3969         return ret;
3970
3971 out_free_ctx:
3972         scrub_free_ctx(sctx);
3973
3974         return ret;
3975 }
3976
3977 void btrfs_scrub_pause(struct btrfs_fs_info *fs_info)
3978 {
3979         mutex_lock(&fs_info->scrub_lock);
3980         atomic_inc(&fs_info->scrub_pause_req);
3981         while (atomic_read(&fs_info->scrubs_paused) !=
3982                atomic_read(&fs_info->scrubs_running)) {
3983                 mutex_unlock(&fs_info->scrub_lock);
3984                 wait_event(fs_info->scrub_pause_wait,
3985                            atomic_read(&fs_info->scrubs_paused) ==
3986                            atomic_read(&fs_info->scrubs_running));
3987                 mutex_lock(&fs_info->scrub_lock);
3988         }
3989         mutex_unlock(&fs_info->scrub_lock);
3990 }
3991
3992 void btrfs_scrub_continue(struct btrfs_fs_info *fs_info)
3993 {
3994         atomic_dec(&fs_info->scrub_pause_req);
3995         wake_up(&fs_info->scrub_pause_wait);
3996 }
3997
3998 int btrfs_scrub_cancel(struct btrfs_fs_info *fs_info)
3999 {
4000         mutex_lock(&fs_info->scrub_lock);
4001         if (!atomic_read(&fs_info->scrubs_running)) {
4002                 mutex_unlock(&fs_info->scrub_lock);
4003                 return -ENOTCONN;
4004         }
4005
4006         atomic_inc(&fs_info->scrub_cancel_req);
4007         while (atomic_read(&fs_info->scrubs_running)) {
4008                 mutex_unlock(&fs_info->scrub_lock);
4009                 wait_event(fs_info->scrub_pause_wait,
4010                            atomic_read(&fs_info->scrubs_running) == 0);
4011                 mutex_lock(&fs_info->scrub_lock);
4012         }
4013         atomic_dec(&fs_info->scrub_cancel_req);
4014         mutex_unlock(&fs_info->scrub_lock);
4015
4016         return 0;
4017 }
4018
4019 int btrfs_scrub_cancel_dev(struct btrfs_device *dev)
4020 {
4021         struct btrfs_fs_info *fs_info = dev->fs_info;
4022         struct scrub_ctx *sctx;
4023
4024         mutex_lock(&fs_info->scrub_lock);
4025         sctx = dev->scrub_ctx;
4026         if (!sctx) {
4027                 mutex_unlock(&fs_info->scrub_lock);
4028                 return -ENOTCONN;
4029         }
4030         atomic_inc(&sctx->cancel_req);
4031         while (dev->scrub_ctx) {
4032                 mutex_unlock(&fs_info->scrub_lock);
4033                 wait_event(fs_info->scrub_pause_wait,
4034                            dev->scrub_ctx == NULL);
4035                 mutex_lock(&fs_info->scrub_lock);
4036         }
4037         mutex_unlock(&fs_info->scrub_lock);
4038
4039         return 0;
4040 }
4041
4042 int btrfs_scrub_progress(struct btrfs_fs_info *fs_info, u64 devid,
4043                          struct btrfs_scrub_progress *progress)
4044 {
4045         struct btrfs_device *dev;
4046         struct scrub_ctx *sctx = NULL;
4047
4048         mutex_lock(&fs_info->fs_devices->device_list_mutex);
4049         dev = btrfs_find_device(fs_info->fs_devices, devid, NULL, NULL, true);
4050         if (dev)
4051                 sctx = dev->scrub_ctx;
4052         if (sctx)
4053                 memcpy(progress, &sctx->stat, sizeof(*progress));
4054         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
4055
4056         return dev ? (sctx ? 0 : -ENOTCONN) : -ENODEV;
4057 }
4058
4059 static void scrub_remap_extent(struct btrfs_fs_info *fs_info,
4060                                u64 extent_logical, u64 extent_len,
4061                                u64 *extent_physical,
4062                                struct btrfs_device **extent_dev,
4063                                int *extent_mirror_num)
4064 {
4065         u64 mapped_length;
4066         struct btrfs_bio *bbio = NULL;
4067         int ret;
4068
4069         mapped_length = extent_len;
4070         ret = btrfs_map_block(fs_info, BTRFS_MAP_READ, extent_logical,
4071                               &mapped_length, &bbio, 0);
4072         if (ret || !bbio || mapped_length < extent_len ||
4073             !bbio->stripes[0].dev->bdev) {
4074                 btrfs_put_bbio(bbio);
4075                 return;
4076         }
4077
4078         *extent_physical = bbio->stripes[0].physical;
4079         *extent_mirror_num = bbio->mirror_num;
4080         *extent_dev = bbio->stripes[0].dev;
4081         btrfs_put_bbio(bbio);
4082 }