fs/btrfs/scrub.c

   1 /*
   2  * Copyright (C) 2011, 2012 STRATO.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/blkdev.h>
  20 #include <linux/ratelimit.h>
  21 #include "ctree.h"
  22 #include "volumes.h"
  23 #include "disk-io.h"
  24 #include "ordered-data.h"
  25 #include "transaction.h"
  26 #include "backref.h"
  27 #include "extent_io.h"
  28 #include "dev-replace.h"
  29 #include "check-integrity.h"
  30 #include "rcu-string.h"
  31 #include "raid56.h"
  32
  33 /*
  34  * This is only the first step towards a full-features scrub. It reads all
  35  * extent and super block and verifies the checksums. In case a bad checksum
  36  * is found or the extent cannot be read, good data will be written back if
  37  * any can be found.
  38  *
  39  * Future enhancements:
  40  *  - In case an unrepairable extent is encountered, track which files are
  41  *    affected and report them
  42  *  - track and record media errors, throw out bad devices
  43  *  - add a mode to also read unallocated space
  44  */
  45
  46 struct scrub_block;
  47 struct scrub_ctx;
  48
  49 /*
  50  * the following three values only influence the performance.
  51  * The last one configures the number of parallel and outstanding I/O
  52  * operations. The first two values configure an upper limit for the number
  53  * of (dynamically allocated) pages that are added to a bio.
  54  */
  55 #define SCRUB_PAGES_PER_RD_BIO  32      /* 128k per bio */
  56 #define SCRUB_PAGES_PER_WR_BIO  32      /* 128k per bio */
  57 #define SCRUB_BIOS_PER_SCTX     64      /* 8MB per device in flight */
  58
  59 /*
  60  * the following value times PAGE_SIZE needs to be large enough to match the
  61  * largest node/leaf/sector size that shall be supported.
  62  * Values larger than BTRFS_STRIPE_LEN are not supported.
  63  */
  64 #define SCRUB_MAX_PAGES_PER_BLOCK       16      /* 64k per node/leaf/sector */
  65
  66 struct scrub_recover {
  67         atomic_t                refs;
  68         struct btrfs_bio        *bbio;
  69         u64                     map_length;
  70 };
  71
  72 struct scrub_page {
  73         struct scrub_block      *sblock;
  74         struct page             *page;
  75         struct btrfs_device     *dev;
  76         struct list_head        list;
  77         u64                     flags;  /* extent flags */
  78         u64                     generation;
  79         u64                     logical;
  80         u64                     physical;
  81         u64                     physical_for_dev_replace;
  82         atomic_t                refs;
  83         struct {
  84                 unsigned int    mirror_num:8;
  85                 unsigned int    have_csum:1;
  86                 unsigned int    io_error:1;
  87         };
  88         u8                      csum[BTRFS_CSUM_SIZE];
  89
  90         struct scrub_recover    *recover;
  91 };
  92
  93 struct scrub_bio {
  94         int                     index;
  95         struct scrub_ctx        *sctx;
  96         struct btrfs_device     *dev;
  97         struct bio              *bio;
  98         int                     err;
  99         u64                     logical;
 100         u64                     physical;
 101 #if SCRUB_PAGES_PER_WR_BIO >= SCRUB_PAGES_PER_RD_BIO
 102         struct scrub_page       *pagev[SCRUB_PAGES_PER_WR_BIO];
 103 #else
 104         struct scrub_page       *pagev[SCRUB_PAGES_PER_RD_BIO];
 105 #endif
 106         int                     page_count;
 107         int                     next_free;
 108         struct btrfs_work       work;
 109 };
 110
 111 struct scrub_block {
 112         struct scrub_page       *pagev[SCRUB_MAX_PAGES_PER_BLOCK];
 113         int                     page_count;
 114         atomic_t                outstanding_pages;
 115         atomic_t                refs; /* free mem on transition to zero */
 116         struct scrub_ctx        *sctx;
 117         struct scrub_parity     *sparity;
 118         struct {
 119                 unsigned int    header_error:1;
 120                 unsigned int    checksum_error:1;
 121                 unsigned int    no_io_error_seen:1;
 122                 unsigned int    generation_error:1; /* also sets header_error */
 123
 124                 /* The following is for the data used to check parity */
 125                 /* It is for the data with checksum */
 126                 unsigned int    data_corrected:1;
 127         };
 128         struct btrfs_work       work;
 129 };
 130
 131 /* Used for the chunks with parity stripe such RAID5/6 */
 132 struct scrub_parity {
 133         struct scrub_ctx        *sctx;
 134
 135         struct btrfs_device     *scrub_dev;
 136
 137         u64                     logic_start;
 138
 139         u64                     logic_end;
 140
 141         int                     nsectors;
 142
 143         int                     stripe_len;
 144
 145         atomic_t                refs;
 146
 147         struct list_head        spages;
 148
 149         /* Work of parity check and repair */
 150         struct btrfs_work       work;
 151
 152         /* Mark the parity blocks which have data */
 153         unsigned long           *dbitmap;
 154
 155         /*
 156          * Mark the parity blocks which have data, but errors happen when
 157          * read data or check data
 158          */
 159         unsigned long           *ebitmap;
 160
 161         unsigned long           bitmap[0];
 162 };
 163
 164 struct scrub_wr_ctx {
 165         struct scrub_bio *wr_curr_bio;
 166         struct btrfs_device *tgtdev;
 167         int pages_per_wr_bio; /* <= SCRUB_PAGES_PER_WR_BIO */
 168         atomic_t flush_all_writes;
 169         struct mutex wr_lock;
 170 };
 171
 172 struct scrub_ctx {
 173         struct scrub_bio        *bios[SCRUB_BIOS_PER_SCTX];
 174         struct btrfs_root       *dev_root;
 175         int                     first_free;
 176         int                     curr;
 177         atomic_t                bios_in_flight;
 178         atomic_t                workers_pending;
 179         spinlock_t              list_lock;
 180         wait_queue_head_t       list_wait;
 181         u16                     csum_size;
 182         struct list_head        csum_list;
 183         atomic_t                cancel_req;
 184         int                     readonly;
 185         int                     pages_per_rd_bio;
 186         u32                     sectorsize;
 187         u32                     nodesize;
 188
 189         int                     is_dev_replace;
 190         struct scrub_wr_ctx     wr_ctx;
 191
 192         /*
 193          * statistics
 194          */
 195         struct btrfs_scrub_progress stat;
 196         spinlock_t              stat_lock;
 197
 198         /*
 199          * Use a ref counter to avoid use-after-free issues. Scrub workers
 200          * decrement bios_in_flight and workers_pending and then do a wakeup
 201          * on the list_wait wait queue. We must ensure the main scrub task
 202          * doesn't free the scrub context before or while the workers are
 203          * doing the wakeup() call.
 204          */
 205         atomic_t                refs;
 206 };
 207
 208 struct scrub_fixup_nodatasum {
 209         struct scrub_ctx        *sctx;
 210         struct btrfs_device     *dev;
 211         u64                     logical;
 212         struct btrfs_root       *root;
 213         struct btrfs_work       work;
 214         int                     mirror_num;
 215 };
 216
 217 struct scrub_nocow_inode {
 218         u64                     inum;
 219         u64                     offset;
 220         u64                     root;
 221         struct list_head        list;
 222 };
 223
 224 struct scrub_copy_nocow_ctx {
 225         struct scrub_ctx        *sctx;
 226         u64                     logical;
 227         u64                     len;
 228         int                     mirror_num;
 229         u64                     physical_for_dev_replace;
 230         struct list_head        inodes;
 231         struct btrfs_work       work;
 232 };
 233
 234 struct scrub_warning {
 235         struct btrfs_path       *path;
 236         u64                     extent_item_size;
 237         const char              *errstr;
 238         sector_t                sector;
 239         u64                     logical;
 240         struct btrfs_device     *dev;
 241 };
 242
 243 static void scrub_pending_bio_inc(struct scrub_ctx *sctx);
 244 static void scrub_pending_bio_dec(struct scrub_ctx *sctx);
 245 static void scrub_pending_trans_workers_inc(struct scrub_ctx *sctx);
 246 static void scrub_pending_trans_workers_dec(struct scrub_ctx *sctx);
 247 static int scrub_handle_errored_block(struct scrub_block *sblock_to_check);
 248 static int scrub_setup_recheck_block(struct scrub_block *original_sblock,
 249                                      struct scrub_block *sblocks_for_recheck);
 250 static void scrub_recheck_block(struct btrfs_fs_info *fs_info,
 251                                 struct scrub_block *sblock,
 252                                 int retry_failed_mirror);
 253 static void scrub_recheck_block_checksum(struct scrub_block *sblock);
 254 static int scrub_repair_block_from_good_copy(struct scrub_block *sblock_bad,
 255                                              struct scrub_block *sblock_good);
 256 static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
 257                                             struct scrub_block *sblock_good,
 258                                             int page_num, int force_write);
 259 static void scrub_write_block_to_dev_replace(struct scrub_block *sblock);
 260 static int scrub_write_page_to_dev_replace(struct scrub_block *sblock,
 261                                            int page_num);
 262 static int scrub_checksum_data(struct scrub_block *sblock);
 263 static int scrub_checksum_tree_block(struct scrub_block *sblock);
 264 static int scrub_checksum_super(struct scrub_block *sblock);
 265 static void scrub_block_get(struct scrub_block *sblock);
 266 static void scrub_block_put(struct scrub_block *sblock);
 267 static void scrub_page_get(struct scrub_page *spage);
 268 static void scrub_page_put(struct scrub_page *spage);
 269 static void scrub_parity_get(struct scrub_parity *sparity);
 270 static void scrub_parity_put(struct scrub_parity *sparity);
 271 static int scrub_add_page_to_rd_bio(struct scrub_ctx *sctx,
 272                                     struct scrub_page *spage);
 273 static int scrub_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
 274                        u64 physical, struct btrfs_device *dev, u64 flags,
 275                        u64 gen, int mirror_num, u8 *csum, int force,
 276                        u64 physical_for_dev_replace);
 277 static void scrub_bio_end_io(struct bio *bio);
 278 static void scrub_bio_end_io_worker(struct btrfs_work *work);
 279 static void scrub_block_complete(struct scrub_block *sblock);
 280 static void scrub_remap_extent(struct btrfs_fs_info *fs_info,
 281                                u64 extent_logical, u64 extent_len,
 282                                u64 *extent_physical,
 283                                struct btrfs_device **extent_dev,
 284                                int *extent_mirror_num);
 285 static int scrub_setup_wr_ctx(struct scrub_ctx *sctx,
 286                               struct scrub_wr_ctx *wr_ctx,
 287                               struct btrfs_fs_info *fs_info,
 288                               struct btrfs_device *dev,
 289                               int is_dev_replace);
 290 static void scrub_free_wr_ctx(struct scrub_wr_ctx *wr_ctx);
 291 static int scrub_add_page_to_wr_bio(struct scrub_ctx *sctx,
 292                                     struct scrub_page *spage);
 293 static void scrub_wr_submit(struct scrub_ctx *sctx);
 294 static void scrub_wr_bio_end_io(struct bio *bio);
 295 static void scrub_wr_bio_end_io_worker(struct btrfs_work *work);
 296 static int write_page_nocow(struct scrub_ctx *sctx,
 297                             u64 physical_for_dev_replace, struct page *page);
 298 static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root,
 299                                       struct scrub_copy_nocow_ctx *ctx);
 300 static int copy_nocow_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
 301                             int mirror_num, u64 physical_for_dev_replace);
 302 static void copy_nocow_pages_worker(struct btrfs_work *work);
 303 static void __scrub_blocked_if_needed(struct btrfs_fs_info *fs_info);
 304 static void scrub_blocked_if_needed(struct btrfs_fs_info *fs_info);
 305 static void scrub_put_ctx(struct scrub_ctx *sctx);
 306
 307
 308 static void scrub_pending_bio_inc(struct scrub_ctx *sctx)
 309 {
 310         atomic_inc(&sctx->refs);
 311         atomic_inc(&sctx->bios_in_flight);
 312 }
 313
 314 static void scrub_pending_bio_dec(struct scrub_ctx *sctx)
 315 {
 316         atomic_dec(&sctx->bios_in_flight);
 317         wake_up(&sctx->list_wait);
 318         scrub_put_ctx(sctx);
 319 }
 320
 321 static void __scrub_blocked_if_needed(struct btrfs_fs_info *fs_info)
 322 {
 323         while (atomic_read(&fs_info->scrub_pause_req)) {
 324                 mutex_unlock(&fs_info->scrub_lock);
 325                 wait_event(fs_info->scrub_pause_wait,
 326                    atomic_read(&fs_info->scrub_pause_req) == 0);
 327                 mutex_lock(&fs_info->scrub_lock);
 328         }
 329 }
 330
 331 static void scrub_pause_on(struct btrfs_fs_info *fs_info)
 332 {
 333         atomic_inc(&fs_info->scrubs_paused);
 334         wake_up(&fs_info->scrub_pause_wait);
 335 }
 336
 337 static void scrub_pause_off(struct btrfs_fs_info *fs_info)
 338 {
 339         mutex_lock(&fs_info->scrub_lock);
 340         __scrub_blocked_if_needed(fs_info);
 341         atomic_dec(&fs_info->scrubs_paused);
 342         mutex_unlock(&fs_info->scrub_lock);
 343
 344         wake_up(&fs_info->scrub_pause_wait);
 345 }
 346
 347 static void scrub_blocked_if_needed(struct btrfs_fs_info *fs_info)
 348 {
 349         scrub_pause_on(fs_info);
 350         scrub_pause_off(fs_info);
 351 }
 352
 353 /*
 354  * used for workers that require transaction commits (i.e., for the
 355  * NOCOW case)
 356  */
 357 static void scrub_pending_trans_workers_inc(struct scrub_ctx *sctx)
 358 {
 359         struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;
 360
 361         atomic_inc(&sctx->refs);
 362         /*
 363          * increment scrubs_running to prevent cancel requests from
 364          * completing as long as a worker is running. we must also
 365          * increment scrubs_paused to prevent deadlocking on pause
 366          * requests used for transactions commits (as the worker uses a
 367          * transaction context). it is safe to regard the worker
 368          * as paused for all matters practical. effectively, we only
 369          * avoid cancellation requests from completing.
 370          */
 371         mutex_lock(&fs_info->scrub_lock);
 372         atomic_inc(&fs_info->scrubs_running);
 373         atomic_inc(&fs_info->scrubs_paused);
 374         mutex_unlock(&fs_info->scrub_lock);
 375
 376         /*
 377          * check if @scrubs_running=@scrubs_paused condition
 378          * inside wait_event() is not an atomic operation.
 379          * which means we may inc/dec @scrub_running/paused
 380          * at any time. Let's wake up @scrub_pause_wait as
 381          * much as we can to let commit transaction blocked less.
 382          */
 383         wake_up(&fs_info->scrub_pause_wait);
 384
 385         atomic_inc(&sctx->workers_pending);
 386 }
 387
 388 /* used for workers that require transaction commits */
 389 static void scrub_pending_trans_workers_dec(struct scrub_ctx *sctx)
 390 {
 391         struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;
 392
 393         /*
 394          * see scrub_pending_trans_workers_inc() why we're pretending
 395          * to be paused in the scrub counters
 396          */
 397         mutex_lock(&fs_info->scrub_lock);
 398         atomic_dec(&fs_info->scrubs_running);
 399         atomic_dec(&fs_info->scrubs_paused);
 400         mutex_unlock(&fs_info->scrub_lock);
 401         atomic_dec(&sctx->workers_pending);
 402         wake_up(&fs_info->scrub_pause_wait);
 403         wake_up(&sctx->list_wait);
 404         scrub_put_ctx(sctx);
 405 }
 406
 407 static void scrub_free_csums(struct scrub_ctx *sctx)
 408 {
 409         while (!list_empty(&sctx->csum_list)) {
 410                 struct btrfs_ordered_sum *sum;
 411                 sum = list_first_entry(&sctx->csum_list,
 412                                        struct btrfs_ordered_sum, list);
 413                 list_del(&sum->list);
 414                 kfree(sum);
 415         }
 416 }
 417
 418 static noinline_for_stack void scrub_free_ctx(struct scrub_ctx *sctx)
 419 {
 420         int i;
 421
 422         if (!sctx)
 423                 return;
 424
 425         scrub_free_wr_ctx(&sctx->wr_ctx);
 426
 427         /* this can happen when scrub is cancelled */
 428         if (sctx->curr != -1) {
 429                 struct scrub_bio *sbio = sctx->bios[sctx->curr];
 430
 431                 for (i = 0; i < sbio->page_count; i++) {
 432                         WARN_ON(!sbio->pagev[i]->page);
 433                         scrub_block_put(sbio->pagev[i]->sblock);
 434                 }
 435                 bio_put(sbio->bio);
 436         }
 437
 438         for (i = 0; i < SCRUB_BIOS_PER_SCTX; ++i) {
 439                 struct scrub_bio *sbio = sctx->bios[i];
 440
 441                 if (!sbio)
 442                         break;
 443                 kfree(sbio);
 444         }
 445
 446         scrub_free_csums(sctx);
 447         kfree(sctx);
 448 }
 449
 450 static void scrub_put_ctx(struct scrub_ctx *sctx)
 451 {
 452         if (atomic_dec_and_test(&sctx->refs))
 453                 scrub_free_ctx(sctx);
 454 }
 455
 456 static noinline_for_stack
 457 struct scrub_ctx *scrub_setup_ctx(struct btrfs_device *dev, int is_dev_replace)
 458 {
 459         struct scrub_ctx *sctx;
 460         int             i;
 461         struct btrfs_fs_info *fs_info = dev->dev_root->fs_info;
 462         int ret;
 463
 464         sctx = kzalloc(sizeof(*sctx), GFP_NOFS);
 465         if (!sctx)
 466                 goto nomem;
 467         atomic_set(&sctx->refs, 1);
 468         sctx->is_dev_replace = is_dev_replace;
 469         sctx->pages_per_rd_bio = SCRUB_PAGES_PER_RD_BIO;
 470         sctx->curr = -1;
 471         sctx->dev_root = dev->dev_root;
 472         for (i = 0; i < SCRUB_BIOS_PER_SCTX; ++i) {
 473                 struct scrub_bio *sbio;
 474
 475                 sbio = kzalloc(sizeof(*sbio), GFP_NOFS);
 476                 if (!sbio)
 477                         goto nomem;
 478                 sctx->bios[i] = sbio;
 479
 480                 sbio->index = i;
 481                 sbio->sctx = sctx;
 482                 sbio->page_count = 0;
 483                 btrfs_init_work(&sbio->work, btrfs_scrub_helper,
 484                                 scrub_bio_end_io_worker, NULL, NULL);
 485
 486                 if (i != SCRUB_BIOS_PER_SCTX - 1)
 487                         sctx->bios[i]->next_free = i + 1;
 488                 else
 489                         sctx->bios[i]->next_free = -1;
 490         }
 491         sctx->first_free = 0;
 492         sctx->nodesize = dev->dev_root->nodesize;
 493         sctx->sectorsize = dev->dev_root->sectorsize;
 494         atomic_set(&sctx->bios_in_flight, 0);
 495         atomic_set(&sctx->workers_pending, 0);
 496         atomic_set(&sctx->cancel_req, 0);
 497         sctx->csum_size = btrfs_super_csum_size(fs_info->super_copy);
 498         INIT_LIST_HEAD(&sctx->csum_list);
 499
 500         spin_lock_init(&sctx->list_lock);
 501         spin_lock_init(&sctx->stat_lock);
 502         init_waitqueue_head(&sctx->list_wait);
 503
 504         ret = scrub_setup_wr_ctx(sctx, &sctx->wr_ctx, fs_info,
 505                                  fs_info->dev_replace.tgtdev, is_dev_replace);
 506         if (ret) {
 507                 scrub_free_ctx(sctx);
 508                 return ERR_PTR(ret);
 509         }
 510         return sctx;
 511
 512 nomem:
 513         scrub_free_ctx(sctx);
 514         return ERR_PTR(-ENOMEM);
 515 }
 516
 517 static int scrub_print_warning_inode(u64 inum, u64 offset, u64 root,
 518                                      void *warn_ctx)
 519 {
 520         u64 isize;
 521         u32 nlink;
 522         int ret;
 523         int i;
 524         struct extent_buffer *eb;
 525         struct btrfs_inode_item *inode_item;
 526         struct scrub_warning *swarn = warn_ctx;
 527         struct btrfs_fs_info *fs_info = swarn->dev->dev_root->fs_info;
 528         struct inode_fs_paths *ipath = NULL;
 529         struct btrfs_root *local_root;
 530         struct btrfs_key root_key;
 531         struct btrfs_key key;
 532
 533         root_key.objectid = root;
 534         root_key.type = BTRFS_ROOT_ITEM_KEY;
 535         root_key.offset = (u64)-1;
 536         local_root = btrfs_read_fs_root_no_name(fs_info, &root_key);
 537         if (IS_ERR(local_root)) {
 538                 ret = PTR_ERR(local_root);
 539                 goto err;
 540         }
 541
 542         /*
 543          * this makes the path point to (inum INODE_ITEM ioff)
 544          */
 545         key.objectid = inum;
 546         key.type = BTRFS_INODE_ITEM_KEY;
 547         key.offset = 0;
 548
 549         ret = btrfs_search_slot(NULL, local_root, &key, swarn->path, 0, 0);
 550         if (ret) {
 551                 btrfs_release_path(swarn->path);
 552                 goto err;
 553         }
 554
 555         eb = swarn->path->nodes[0];
 556         inode_item = btrfs_item_ptr(eb, swarn->path->slots[0],
 557                                         struct btrfs_inode_item);
 558         isize = btrfs_inode_size(eb, inode_item);
 559         nlink = btrfs_inode_nlink(eb, inode_item);
 560         btrfs_release_path(swarn->path);
 561
 562         ipath = init_ipath(4096, local_root, swarn->path);
 563         if (IS_ERR(ipath)) {
 564                 ret = PTR_ERR(ipath);
 565                 ipath = NULL;
 566                 goto err;
 567         }
 568         ret = paths_from_inode(inum, ipath);
 569
 570         if (ret < 0)
 571                 goto err;
 572
 573         /*
 574          * we deliberately ignore the bit ipath might have been too small to
 575          * hold all of the paths here
 576          */
 577         for (i = 0; i < ipath->fspath->elem_cnt; ++i)
 578                 btrfs_warn_in_rcu(fs_info, "%s at logical %llu on dev "
 579                         "%s, sector %llu, root %llu, inode %llu, offset %llu, "
 580                         "length %llu, links %u (path: %s)", swarn->errstr,
 581                         swarn->logical, rcu_str_deref(swarn->dev->name),
 582                         (unsigned long long)swarn->sector, root, inum, offset,
 583                         min(isize - offset, (u64)PAGE_SIZE), nlink,
 584                         (char *)(unsigned long)ipath->fspath->val[i]);
 585
 586         free_ipath(ipath);
 587         return 0;
 588
 589 err:
 590         btrfs_warn_in_rcu(fs_info, "%s at logical %llu on dev "
 591                 "%s, sector %llu, root %llu, inode %llu, offset %llu: path "
 592                 "resolving failed with ret=%d", swarn->errstr,
 593                 swarn->logical, rcu_str_deref(swarn->dev->name),
 594                 (unsigned long long)swarn->sector, root, inum, offset, ret);
 595
 596         free_ipath(ipath);
 597         return 0;
 598 }
 599
 600 static void scrub_print_warning(const char *errstr, struct scrub_block *sblock)
 601 {
 602         struct btrfs_device *dev;
 603         struct btrfs_fs_info *fs_info;
 604         struct btrfs_path *path;
 605         struct btrfs_key found_key;
 606         struct extent_buffer *eb;
 607         struct btrfs_extent_item *ei;
 608         struct scrub_warning swarn;
 609         unsigned long ptr = 0;
 610         u64 extent_item_pos;
 611         u64 flags = 0;
 612         u64 ref_root;
 613         u32 item_size;
 614         u8 ref_level;
 615         int ret;
 616
 617         WARN_ON(sblock->page_count < 1);
 618         dev = sblock->pagev[0]->dev;
 619         fs_info = sblock->sctx->dev_root->fs_info;
 620
 621         path = btrfs_alloc_path();
 622         if (!path)
 623                 return;
 624
 625         swarn.sector = (sblock->pagev[0]->physical) >> 9;
 626         swarn.logical = sblock->pagev[0]->logical;
 627         swarn.errstr = errstr;
 628         swarn.dev = NULL;
 629
 630         ret = extent_from_logical(fs_info, swarn.logical, path, &found_key,
 631                                   &flags);
 632         if (ret < 0)
 633                 goto out;
 634
 635         extent_item_pos = swarn.logical - found_key.objectid;
 636         swarn.extent_item_size = found_key.offset;
 637
 638         eb = path->nodes[0];
 639         ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
 640         item_size = btrfs_item_size_nr(eb, path->slots[0]);
 641
 642         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
 643                 do {
 644                         ret = tree_backref_for_extent(&ptr, eb, &found_key, ei,
 645                                                       item_size, &ref_root,
 646                                                       &ref_level);
 647                         btrfs_warn_in_rcu(fs_info,
 648                                 "%s at logical %llu on dev %s, "
 649                                 "sector %llu: metadata %s (level %d) in tree "
 650                                 "%llu", errstr, swarn.logical,
 651                                 rcu_str_deref(dev->name),
 652                                 (unsigned long long)swarn.sector,
 653                                 ref_level ? "node" : "leaf",
 654                                 ret < 0 ? -1 : ref_level,
 655                                 ret < 0 ? -1 : ref_root);
 656                 } while (ret != 1);
 657                 btrfs_release_path(path);
 658         } else {
 659                 btrfs_release_path(path);
 660                 swarn.path = path;
 661                 swarn.dev = dev;
 662                 iterate_extent_inodes(fs_info, found_key.objectid,
 663                                         extent_item_pos, 1,
 664                                         scrub_print_warning_inode, &swarn);
 665         }
 666
 667 out:
 668         btrfs_free_path(path);
 669 }
 670
 671 static int scrub_fixup_readpage(u64 inum, u64 offset, u64 root, void *fixup_ctx)
 672 {
 673         struct page *page = NULL;
 674         unsigned long index;
 675         struct scrub_fixup_nodatasum *fixup = fixup_ctx;
 676         int ret;
 677         int corrected = 0;
 678         struct btrfs_key key;
 679         struct inode *inode = NULL;
 680         struct btrfs_fs_info *fs_info;
 681         u64 end = offset + PAGE_SIZE - 1;
 682         struct btrfs_root *local_root;
 683         int srcu_index;
 684
 685         key.objectid = root;
 686         key.type = BTRFS_ROOT_ITEM_KEY;
 687         key.offset = (u64)-1;
 688
 689         fs_info = fixup->root->fs_info;
 690         srcu_index = srcu_read_lock(&fs_info->subvol_srcu);
 691
 692         local_root = btrfs_read_fs_root_no_name(fs_info, &key);
 693         if (IS_ERR(local_root)) {
 694                 srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
 695                 return PTR_ERR(local_root);
 696         }
 697
 698         key.type = BTRFS_INODE_ITEM_KEY;
 699         key.objectid = inum;
 700         key.offset = 0;
 701         inode = btrfs_iget(fs_info->sb, &key, local_root, NULL);
 702         srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
 703         if (IS_ERR(inode))
 704                 return PTR_ERR(inode);
 705
 706         index = offset >> PAGE_CACHE_SHIFT;
 707
 708         page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
 709         if (!page) {
 710                 ret = -ENOMEM;
 711                 goto out;
 712         }
 713
 714         if (PageUptodate(page)) {
 715                 if (PageDirty(page)) {
 716                         /*
 717                          * we need to write the data to the defect sector. the
 718                          * data that was in that sector is not in memory,
 719                          * because the page was modified. we must not write the
 720                          * modified page to that sector.
 721                          *
 722                          * TODO: what could be done here: wait for the delalloc
 723                          *       runner to write out that page (might involve
 724                          *       COW) and see whether the sector is still
 725                          *       referenced afterwards.
 726                          *
 727                          * For the meantime, we'll treat this error
 728                          * incorrectable, although there is a chance that a
 729                          * later scrub will find the bad sector again and that
 730                          * there's no dirty page in memory, then.
 731                          */
 732                         ret = -EIO;
 733                         goto out;
 734                 }
 735                 ret = repair_io_failure(inode, offset, PAGE_SIZE,
 736                                         fixup->logical, page,
 737                                         offset - page_offset(page),
 738                                         fixup->mirror_num);
 739                 unlock_page(page);
 740                 corrected = !ret;
 741         } else {
 742                 /*
 743                  * we need to get good data first. the general readpage path
 744                  * will call repair_io_failure for us, we just have to make
 745                  * sure we read the bad mirror.
 746                  */
 747                 ret = set_extent_bits(&BTRFS_I(inode)->io_tree, offset, end,
 748                                         EXTENT_DAMAGED, GFP_NOFS);
 749                 if (ret) {
 750                         /* set_extent_bits should give proper error */
 751                         WARN_ON(ret > 0);
 752                         if (ret > 0)
 753                                 ret = -EFAULT;
 754                         goto out;
 755                 }
 756
 757                 ret = extent_read_full_page(&BTRFS_I(inode)->io_tree, page,
 758                                                 btrfs_get_extent,
 759                                                 fixup->mirror_num);
 760                 wait_on_page_locked(page);
 761
 762                 corrected = !test_range_bit(&BTRFS_I(inode)->io_tree, offset,
 763                                                 end, EXTENT_DAMAGED, 0, NULL);
 764                 if (!corrected)
 765                         clear_extent_bits(&BTRFS_I(inode)->io_tree, offset, end,
 766                                                 EXTENT_DAMAGED, GFP_NOFS);
 767         }
 768
 769 out:
 770         if (page)
 771                 put_page(page);
 772
 773         iput(inode);
 774
 775         if (ret < 0)
 776                 return ret;
 777
 778         if (ret == 0 && corrected) {
 779                 /*
 780                  * we only need to call readpage for one of the inodes belonging
 781                  * to this extent. so make iterate_extent_inodes stop
 782                  */
 783                 return 1;
 784         }
 785
 786         return -EIO;
 787 }
 788
 789 static void scrub_fixup_nodatasum(struct btrfs_work *work)
 790 {
 791         int ret;
 792         struct scrub_fixup_nodatasum *fixup;
 793         struct scrub_ctx *sctx;
 794         struct btrfs_trans_handle *trans = NULL;
 795         struct btrfs_path *path;
 796         int uncorrectable = 0;
 797
 798         fixup = container_of(work, struct scrub_fixup_nodatasum, work);
 799         sctx = fixup->sctx;
 800
 801         path = btrfs_alloc_path();
 802         if (!path) {
 803                 spin_lock(&sctx->stat_lock);
 804                 ++sctx->stat.malloc_errors;
 805                 spin_unlock(&sctx->stat_lock);
 806                 uncorrectable = 1;
 807                 goto out;
 808         }
 809
 810         trans = btrfs_join_transaction(fixup->root);
 811         if (IS_ERR(trans)) {
 812                 uncorrectable = 1;
 813                 goto out;
 814         }
 815
 816         /*
 817          * the idea is to trigger a regular read through the standard path. we
 818          * read a page from the (failed) logical address by specifying the
 819          * corresponding copynum of the failed sector. thus, that readpage is
 820          * expected to fail.
 821          * that is the point where on-the-fly error correction will kick in
 822          * (once it's finished) and rewrite the failed sector if a good copy
 823          * can be found.
 824          */
 825         ret = iterate_inodes_from_logical(fixup->logical, fixup->root->fs_info,
 826                                                 path, scrub_fixup_readpage,
 827                                                 fixup);
 828         if (ret < 0) {
 829                 uncorrectable = 1;
 830                 goto out;
 831         }
 832         WARN_ON(ret != 1);
 833
 834         spin_lock(&sctx->stat_lock);
 835         ++sctx->stat.corrected_errors;
 836         spin_unlock(&sctx->stat_lock);
 837
 838 out:
 839         if (trans && !IS_ERR(trans))
 840                 btrfs_end_transaction(trans, fixup->root);
 841         if (uncorrectable) {
 842                 spin_lock(&sctx->stat_lock);
 843                 ++sctx->stat.uncorrectable_errors;
 844                 spin_unlock(&sctx->stat_lock);
 845                 btrfs_dev_replace_stats_inc(
 846                         &sctx->dev_root->fs_info->dev_replace.
 847                         num_uncorrectable_read_errors);
 848                 btrfs_err_rl_in_rcu(sctx->dev_root->fs_info,
 849                     "unable to fixup (nodatasum) error at logical %llu on dev %s",
 850                         fixup->logical, rcu_str_deref(fixup->dev->name));
 851         }
 852
 853         btrfs_free_path(path);
 854         kfree(fixup);
 855
 856         scrub_pending_trans_workers_dec(sctx);
 857 }
 858
 859 static inline void scrub_get_recover(struct scrub_recover *recover)
 860 {
 861         atomic_inc(&recover->refs);
 862 }
 863
 864 static inline void scrub_put_recover(struct scrub_recover *recover)
 865 {
 866         if (atomic_dec_and_test(&recover->refs)) {
 867                 btrfs_put_bbio(recover->bbio);
 868                 kfree(recover);
 869         }
 870 }
 871
 872 /*
 873  * scrub_handle_errored_block gets called when either verification of the
 874  * pages failed or the bio failed to read, e.g. with EIO. In the latter
 875  * case, this function handles all pages in the bio, even though only one
 876  * may be bad.
 877  * The goal of this function is to repair the errored block by using the
 878  * contents of one of the mirrors.
 879  */
 880 static int scrub_handle_errored_block(struct scrub_block *sblock_to_check)
 881 {
 882         struct scrub_ctx *sctx = sblock_to_check->sctx;
 883         struct btrfs_device *dev;
 884         struct btrfs_fs_info *fs_info;
 885         u64 length;
 886         u64 logical;
 887         unsigned int failed_mirror_index;
 888         unsigned int is_metadata;
 889         unsigned int have_csum;
 890         struct scrub_block *sblocks_for_recheck; /* holds one for each mirror */
 891         struct scrub_block *sblock_bad;
 892         int ret;
 893         int mirror_index;
 894         int page_num;
 895         int success;
 896         static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
 897                                       DEFAULT_RATELIMIT_BURST);
 898
 899         BUG_ON(sblock_to_check->page_count < 1);
 900         fs_info = sctx->dev_root->fs_info;
 901         if (sblock_to_check->pagev[0]->flags & BTRFS_EXTENT_FLAG_SUPER) {
 902                 /*
 903                  * if we find an error in a super block, we just report it.
 904                  * They will get written with the next transaction commit
 905                  * anyway
 906                  */
 907                 spin_lock(&sctx->stat_lock);
 908                 ++sctx->stat.super_errors;
 909                 spin_unlock(&sctx->stat_lock);
 910                 return 0;
 911         }
 912         length = sblock_to_check->page_count * PAGE_SIZE;
 913         logical = sblock_to_check->pagev[0]->logical;
 914         BUG_ON(sblock_to_check->pagev[0]->mirror_num < 1);
 915         failed_mirror_index = sblock_to_check->pagev[0]->mirror_num - 1;
 916         is_metadata = !(sblock_to_check->pagev[0]->flags &
 917                         BTRFS_EXTENT_FLAG_DATA);
 918         have_csum = sblock_to_check->pagev[0]->have_csum;
 919         dev = sblock_to_check->pagev[0]->dev;
 920
 921         if (sctx->is_dev_replace && !is_metadata && !have_csum) {
 922                 sblocks_for_recheck = NULL;
 923                 goto nodatasum_case;
 924         }
 925
 926         /*
 927          * read all mirrors one after the other. This includes to
 928          * re-read the extent or metadata block that failed (that was
 929          * the cause that this fixup code is called) another time,
 930          * page by page this time in order to know which pages
 931          * caused I/O errors and which ones are good (for all mirrors).
 932          * It is the goal to handle the situation when more than one
 933          * mirror contains I/O errors, but the errors do not
 934          * overlap, i.e. the data can be repaired by selecting the
 935          * pages from those mirrors without I/O error on the
 936          * particular pages. One example (with blocks >= 2 * PAGE_SIZE)
 937          * would be that mirror #1 has an I/O error on the first page,
 938          * the second page is good, and mirror #2 has an I/O error on
 939          * the second page, but the first page is good.
 940          * Then the first page of the first mirror can be repaired by
 941          * taking the first page of the second mirror, and the
 942          * second page of the second mirror can be repaired by
 943          * copying the contents of the 2nd page of the 1st mirror.
 944          * One more note: if the pages of one mirror contain I/O
 945          * errors, the checksum cannot be verified. In order to get
 946          * the best data for repairing, the first attempt is to find
 947          * a mirror without I/O errors and with a validated checksum.
 948          * Only if this is not possible, the pages are picked from
 949          * mirrors with I/O errors without considering the checksum.
 950          * If the latter is the case, at the end, the checksum of the
 951          * repaired area is verified in order to correctly maintain
 952          * the statistics.
 953          */
 954
 955         sblocks_for_recheck = kcalloc(BTRFS_MAX_MIRRORS,
 956                                       sizeof(*sblocks_for_recheck), GFP_NOFS);
 957         if (!sblocks_for_recheck) {
 958                 spin_lock(&sctx->stat_lock);
 959                 sctx->stat.malloc_errors++;
 960                 sctx->stat.read_errors++;
 961                 sctx->stat.uncorrectable_errors++;
 962                 spin_unlock(&sctx->stat_lock);
 963                 btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
 964                 goto out;
 965         }
 966
 967         /* setup the context, map the logical blocks and alloc the pages */
 968         ret = scrub_setup_recheck_block(sblock_to_check, sblocks_for_recheck);
 969         if (ret) {
 970                 spin_lock(&sctx->stat_lock);
 971                 sctx->stat.read_errors++;
 972                 sctx->stat.uncorrectable_errors++;
 973                 spin_unlock(&sctx->stat_lock);
 974                 btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
 975                 goto out;
 976         }
 977         BUG_ON(failed_mirror_index >= BTRFS_MAX_MIRRORS);
 978         sblock_bad = sblocks_for_recheck + failed_mirror_index;
 979
 980         /* build and submit the bios for the failed mirror, check checksums */
 981         scrub_recheck_block(fs_info, sblock_bad, 1);
 982
 983         if (!sblock_bad->header_error && !sblock_bad->checksum_error &&
 984             sblock_bad->no_io_error_seen) {
 985                 /*
 986                  * the error disappeared after reading page by page, or
 987                  * the area was part of a huge bio and other parts of the
 988                  * bio caused I/O errors, or the block layer merged several
 989                  * read requests into one and the error is caused by a
 990                  * different bio (usually one of the two latter cases is
 991                  * the cause)
 992                  */
 993                 spin_lock(&sctx->stat_lock);
 994                 sctx->stat.unverified_errors++;
 995                 sblock_to_check->data_corrected = 1;
 996                 spin_unlock(&sctx->stat_lock);
 997
 998                 if (sctx->is_dev_replace)
 999                         scrub_write_block_to_dev_replace(sblock_bad);
1000                 goto out;
1001         }
1002
1003         if (!sblock_bad->no_io_error_seen) {
1004                 spin_lock(&sctx->stat_lock);
1005                 sctx->stat.read_errors++;
1006                 spin_unlock(&sctx->stat_lock);
1007                 if (__ratelimit(&_rs))
1008                         scrub_print_warning("i/o error", sblock_to_check);
1009                 btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
1010         } else if (sblock_bad->checksum_error) {
1011                 spin_lock(&sctx->stat_lock);
1012                 sctx->stat.csum_errors++;
1013                 spin_unlock(&sctx->stat_lock);
1014                 if (__ratelimit(&_rs))
1015                         scrub_print_warning("checksum error", sblock_to_check);
1016                 btrfs_dev_stat_inc_and_print(dev,
1017                                              BTRFS_DEV_STAT_CORRUPTION_ERRS);
1018         } else if (sblock_bad->header_error) {
1019                 spin_lock(&sctx->stat_lock);
1020                 sctx->stat.verify_errors++;
1021                 spin_unlock(&sctx->stat_lock);
1022                 if (__ratelimit(&_rs))
1023                         scrub_print_warning("checksum/header error",
1024                                             sblock_to_check);
1025                 if (sblock_bad->generation_error)
1026                         btrfs_dev_stat_inc_and_print(dev,
1027                                 BTRFS_DEV_STAT_GENERATION_ERRS);
1028                 else
1029                         btrfs_dev_stat_inc_and_print(dev,
1030                                 BTRFS_DEV_STAT_CORRUPTION_ERRS);
1031         }
1032
1033         if (sctx->readonly) {
1034                 ASSERT(!sctx->is_dev_replace);
1035                 goto out;
1036         }
1037
1038         if (!is_metadata && !have_csum) {
1039                 struct scrub_fixup_nodatasum *fixup_nodatasum;
1040
1041                 WARN_ON(sctx->is_dev_replace);
1042
1043 nodatasum_case:
1044
1045                 /*
1046                  * !is_metadata and !have_csum, this means that the data
1047                  * might not be COW'ed, that it might be modified
1048                  * concurrently. The general strategy to work on the
1049                  * commit root does not help in the case when COW is not
1050                  * used.
1051                  */
1052                 fixup_nodatasum = kzalloc(sizeof(*fixup_nodatasum), GFP_NOFS);
1053                 if (!fixup_nodatasum)
1054                         goto did_not_correct_error;
1055                 fixup_nodatasum->sctx = sctx;
1056                 fixup_nodatasum->dev = dev;
1057                 fixup_nodatasum->logical = logical;
1058                 fixup_nodatasum->root = fs_info->extent_root;
1059                 fixup_nodatasum->mirror_num = failed_mirror_index + 1;
1060                 scrub_pending_trans_workers_inc(sctx);
1061                 btrfs_init_work(&fixup_nodatasum->work, btrfs_scrub_helper,
1062                                 scrub_fixup_nodatasum, NULL, NULL);
1063                 btrfs_queue_work(fs_info->scrub_workers,
1064                                  &fixup_nodatasum->work);
1065                 goto out;
1066         }
1067
1068         /*
1069          * now build and submit the bios for the other mirrors, check
1070          * checksums.
1071          * First try to pick the mirror which is completely without I/O
1072          * errors and also does not have a checksum error.
1073          * If one is found, and if a checksum is present, the full block
1074          * that is known to contain an error is rewritten. Afterwards
1075          * the block is known to be corrected.
1076          * If a mirror is found which is completely correct, and no
1077          * checksum is present, only those pages are rewritten that had
1078          * an I/O error in the block to be repaired, since it cannot be
1079          * determined, which copy of the other pages is better (and it
1080          * could happen otherwise that a correct page would be
1081          * overwritten by a bad one).
1082          */
1083         for (mirror_index = 0;
1084              mirror_index < BTRFS_MAX_MIRRORS &&
1085              sblocks_for_recheck[mirror_index].page_count > 0;
1086              mirror_index++) {
1087                 struct scrub_block *sblock_other;
1088
1089                 if (mirror_index == failed_mirror_index)
1090                         continue;
1091                 sblock_other = sblocks_for_recheck + mirror_index;
1092
1093                 /* build and submit the bios, check checksums */
1094                 scrub_recheck_block(fs_info, sblock_other, 0);
1095
1096                 if (!sblock_other->header_error &&
1097                     !sblock_other->checksum_error &&
1098                     sblock_other->no_io_error_seen) {
1099                         if (sctx->is_dev_replace) {
1100                                 scrub_write_block_to_dev_replace(sblock_other);
1101                                 goto corrected_error;
1102                         } else {
1103                                 ret = scrub_repair_block_from_good_copy(
1104                                                 sblock_bad, sblock_other);
1105                                 if (!ret)
1106                                         goto corrected_error;
1107                         }
1108                 }
1109         }
1110
1111         if (sblock_bad->no_io_error_seen && !sctx->is_dev_replace)
1112                 goto did_not_correct_error;
1113
1114         /*
1115          * In case of I/O errors in the area that is supposed to be
1116          * repaired, continue by picking good copies of those pages.
1117          * Select the good pages from mirrors to rewrite bad pages from
1118          * the area to fix. Afterwards verify the checksum of the block
1119          * that is supposed to be repaired. This verification step is
1120          * only done for the purpose of statistic counting and for the
1121          * final scrub report, whether errors remain.
1122          * A perfect algorithm could make use of the checksum and try
1123          * all possible combinations of pages from the different mirrors
1124          * until the checksum verification succeeds. For example, when
1125          * the 2nd page of mirror #1 faces I/O errors, and the 2nd page
1126          * of mirror #2 is readable but the final checksum test fails,
1127          * then the 2nd page of mirror #3 could be tried, whether now
1128          * the final checksum succeedes. But this would be a rare
1129          * exception and is therefore not implemented. At least it is
1130          * avoided that the good copy is overwritten.
1131          * A more useful improvement would be to pick the sectors
1132          * without I/O error based on sector sizes (512 bytes on legacy
1133          * disks) instead of on PAGE_SIZE. Then maybe 512 byte of one
1134          * mirror could be repaired by taking 512 byte of a different
1135          * mirror, even if other 512 byte sectors in the same PAGE_SIZE
1136          * area are unreadable.
1137          */
1138         success = 1;
1139         for (page_num = 0; page_num < sblock_bad->page_count;
1140              page_num++) {
1141                 struct scrub_page *page_bad = sblock_bad->pagev[page_num];
1142                 struct scrub_block *sblock_other = NULL;
1143
1144                 /* skip no-io-error page in scrub */
1145                 if (!page_bad->io_error && !sctx->is_dev_replace)
1146                         continue;
1147
1148                 /* try to find no-io-error page in mirrors */
1149                 if (page_bad->io_error) {
1150                         for (mirror_index = 0;
1151                              mirror_index < BTRFS_MAX_MIRRORS &&
1152                              sblocks_for_recheck[mirror_index].page_count > 0;
1153                              mirror_index++) {
1154                                 if (!sblocks_for_recheck[mirror_index].
1155                                     pagev[page_num]->io_error) {
1156                                         sblock_other = sblocks_for_recheck +
1157                                                        mirror_index;
1158                                         break;
1159                                 }
1160                         }
1161                         if (!sblock_other)
1162                                 success = 0;
1163                 }
1164
1165                 if (sctx->is_dev_replace) {
1166                         /*
1167                          * did not find a mirror to fetch the page
1168                          * from. scrub_write_page_to_dev_replace()
1169                          * handles this case (page->io_error), by
1170                          * filling the block with zeros before
1171                          * submitting the write request
1172                          */
1173                         if (!sblock_other)
1174                                 sblock_other = sblock_bad;
1175
1176                         if (scrub_write_page_to_dev_replace(sblock_other,
1177                                                             page_num) != 0) {
1178                                 btrfs_dev_replace_stats_inc(
1179                                         &sctx->dev_root->
1180                                         fs_info->dev_replace.
1181                                         num_write_errors);
1182                                 success = 0;
1183                         }
1184                 } else if (sblock_other) {
1185                         ret = scrub_repair_page_from_good_copy(sblock_bad,
1186                                                                sblock_other,
1187                                                                page_num, 0);
1188                         if (0 == ret)
1189                                 page_bad->io_error = 0;
1190                         else
1191                                 success = 0;
1192                 }
1193         }
1194
1195         if (success && !sctx->is_dev_replace) {
1196                 if (is_metadata || have_csum) {
1197                         /*
1198                          * need to verify the checksum now that all
1199                          * sectors on disk are repaired (the write
1200                          * request for data to be repaired is on its way).
1201                          * Just be lazy and use scrub_recheck_block()
1202                          * which re-reads the data before the checksum
1203                          * is verified, but most likely the data comes out
1204                          * of the page cache.
1205                          */
1206                         scrub_recheck_block(fs_info, sblock_bad, 1);
1207                         if (!sblock_bad->header_error &&
1208                             !sblock_bad->checksum_error &&
1209                             sblock_bad->no_io_error_seen)
1210                                 goto corrected_error;
1211                         else
1212                                 goto did_not_correct_error;
1213                 } else {
1214 corrected_error:
1215                         spin_lock(&sctx->stat_lock);
1216                         sctx->stat.corrected_errors++;
1217                         sblock_to_check->data_corrected = 1;
1218                         spin_unlock(&sctx->stat_lock);
1219                         btrfs_err_rl_in_rcu(fs_info,
1220                                 "fixed up error at logical %llu on dev %s",
1221                                 logical, rcu_str_deref(dev->name));
1222                 }
1223         } else {
1224 did_not_correct_error:
1225                 spin_lock(&sctx->stat_lock);
1226                 sctx->stat.uncorrectable_errors++;
1227                 spin_unlock(&sctx->stat_lock);
1228                 btrfs_err_rl_in_rcu(fs_info,
1229                         "unable to fixup (regular) error at logical %llu on dev %s",
1230                         logical, rcu_str_deref(dev->name));
1231         }
1232
1233 out:
1234         if (sblocks_for_recheck) {
1235                 for (mirror_index = 0; mirror_index < BTRFS_MAX_MIRRORS;
1236                      mirror_index++) {
1237                         struct scrub_block *sblock = sblocks_for_recheck +
1238                                                      mirror_index;
1239                         struct scrub_recover *recover;
1240                         int page_index;
1241
1242                         for (page_index = 0; page_index < sblock->page_count;
1243                              page_index++) {
1244                                 sblock->pagev[page_index]->sblock = NULL;
1245                                 recover = sblock->pagev[page_index]->recover;
1246                                 if (recover) {
1247                                         scrub_put_recover(recover);
1248                                         sblock->pagev[page_index]->recover =
1249                                                                         NULL;
1250                                 }
1251                                 scrub_page_put(sblock->pagev[page_index]);
1252                         }
1253                 }
1254                 kfree(sblocks_for_recheck);
1255         }
1256
1257         return 0;
1258 }
1259
1260 static inline int scrub_nr_raid_mirrors(struct btrfs_bio *bbio)
1261 {
1262         if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID5)
1263                 return 2;
1264         else if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID6)
1265                 return 3;
1266         else
1267                 return (int)bbio->num_stripes;
1268 }
1269
1270 static inline void scrub_stripe_index_and_offset(u64 logical, u64 map_type,
1271                                                  u64 *raid_map,
1272                                                  u64 mapped_length,
1273                                                  int nstripes, int mirror,
1274                                                  int *stripe_index,
1275                                                  u64 *stripe_offset)
1276 {
1277         int i;
1278
1279         if (map_type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
1280                 /* RAID5/6 */
1281                 for (i = 0; i < nstripes; i++) {
1282                         if (raid_map[i] == RAID6_Q_STRIPE ||
1283                             raid_map[i] == RAID5_P_STRIPE)
1284                                 continue;
1285
1286                         if (logical >= raid_map[i] &&
1287                             logical < raid_map[i] + mapped_length)
1288                                 break;
1289                 }
1290
1291                 *stripe_index = i;
1292                 *stripe_offset = logical - raid_map[i];
1293         } else {
1294                 /* The other RAID type */
1295                 *stripe_index = mirror;
1296                 *stripe_offset = 0;
1297         }
1298 }
1299
1300 static int scrub_setup_recheck_block(struct scrub_block *original_sblock,
1301                                      struct scrub_block *sblocks_for_recheck)
1302 {
1303         struct scrub_ctx *sctx = original_sblock->sctx;
1304         struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;
1305         u64 length = original_sblock->page_count * PAGE_SIZE;
1306         u64 logical = original_sblock->pagev[0]->logical;
1307         u64 generation = original_sblock->pagev[0]->generation;
1308         u64 flags = original_sblock->pagev[0]->flags;
1309         u64 have_csum = original_sblock->pagev[0]->have_csum;
1310         struct scrub_recover *recover;
1311         struct btrfs_bio *bbio;
1312         u64 sublen;
1313         u64 mapped_length;
1314         u64 stripe_offset;
1315         int stripe_index;
1316         int page_index = 0;
1317         int mirror_index;
1318         int nmirrors;
1319         int ret;
1320
1321         /*
1322          * note: the two members refs and outstanding_pages
1323          * are not used (and not set) in the blocks that are used for
1324          * the recheck procedure
1325          */
1326
1327         while (length > 0) {
1328                 sublen = min_t(u64, length, PAGE_SIZE);
1329                 mapped_length = sublen;
1330                 bbio = NULL;
1331
1332                 /*
1333                  * with a length of PAGE_SIZE, each returned stripe
1334                  * represents one mirror
1335                  */
1336                 ret = btrfs_map_sblock(fs_info, REQ_GET_READ_MIRRORS, logical,
1337                                        &mapped_length, &bbio, 0, 1);
1338                 if (ret || !bbio || mapped_length < sublen) {
1339                         btrfs_put_bbio(bbio);
1340                         return -EIO;
1341                 }
1342
1343                 recover = kzalloc(sizeof(struct scrub_recover), GFP_NOFS);
1344                 if (!recover) {
1345                         btrfs_put_bbio(bbio);
1346                         return -ENOMEM;
1347                 }
1348
1349                 atomic_set(&recover->refs, 1);
1350                 recover->bbio = bbio;
1351                 recover->map_length = mapped_length;
1352
1353                 BUG_ON(page_index >= SCRUB_PAGES_PER_RD_BIO);
1354
1355                 nmirrors = min(scrub_nr_raid_mirrors(bbio), BTRFS_MAX_MIRRORS);
1356
1357                 for (mirror_index = 0; mirror_index < nmirrors;
1358                      mirror_index++) {
1359                         struct scrub_block *sblock;
1360                         struct scrub_page *page;
1361
1362                         sblock = sblocks_for_recheck + mirror_index;
1363                         sblock->sctx = sctx;
1364
1365                         page = kzalloc(sizeof(*page), GFP_NOFS);
1366                         if (!page) {
1367 leave_nomem:
1368                                 spin_lock(&sctx->stat_lock);
1369                                 sctx->stat.malloc_errors++;
1370                                 spin_unlock(&sctx->stat_lock);
1371                                 scrub_put_recover(recover);
1372                                 return -ENOMEM;
1373                         }
1374                         scrub_page_get(page);
1375                         sblock->pagev[page_index] = page;
1376                         page->sblock = sblock;
1377                         page->flags = flags;
1378                         page->generation = generation;
1379                         page->logical = logical;
1380                         page->have_csum = have_csum;
1381                         if (have_csum)
1382                                 memcpy(page->csum,
1383                                        original_sblock->pagev[0]->csum,
1384                                        sctx->csum_size);
1385
1386                         scrub_stripe_index_and_offset(logical,
1387                                                       bbio->map_type,
1388                                                       bbio->raid_map,
1389                                                       mapped_length,
1390                                                       bbio->num_stripes -
1391                                                       bbio->num_tgtdevs,
1392                                                       mirror_index,
1393                                                       &stripe_index,
1394                                                       &stripe_offset);
1395                         page->physical = bbio->stripes[stripe_index].physical +
1396                                          stripe_offset;
1397                         page->dev = bbio->stripes[stripe_index].dev;
1398
1399                         BUG_ON(page_index >= original_sblock->page_count);
1400                         page->physical_for_dev_replace =
1401                                 original_sblock->pagev[page_index]->
1402                                 physical_for_dev_replace;
1403                         /* for missing devices, dev->bdev is NULL */
1404                         page->mirror_num = mirror_index + 1;
1405                         sblock->page_count++;
1406                         page->page = alloc_page(GFP_NOFS);
1407                         if (!page->page)
1408                                 goto leave_nomem;
1409
1410                         scrub_get_recover(recover);
1411                         page->recover = recover;
1412                 }
1413                 scrub_put_recover(recover);
1414                 length -= sublen;
1415                 logical += sublen;
1416                 page_index++;
1417         }
1418
1419         return 0;
1420 }
1421
1422 struct scrub_bio_ret {
1423         struct completion event;
1424         int error;
1425 };
1426
1427 static void scrub_bio_wait_endio(struct bio *bio)
1428 {
1429         struct scrub_bio_ret *ret = bio->bi_private;
1430
1431         ret->error = bio->bi_error;
1432         complete(&ret->event);
1433 }
1434
1435 static inline int scrub_is_page_on_raid56(struct scrub_page *page)
1436 {
1437         return page->recover &&
1438                (page->recover->bbio->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK);
1439 }
1440
1441 static int scrub_submit_raid56_bio_wait(struct btrfs_fs_info *fs_info,
1442                                         struct bio *bio,
1443                                         struct scrub_page *page)
1444 {
1445         struct scrub_bio_ret done;
1446         int ret;
1447
1448         init_completion(&done.event);
1449         done.error = 0;
1450         bio->bi_iter.bi_sector = page->logical >> 9;
1451         bio->bi_private = &done;
1452         bio->bi_end_io = scrub_bio_wait_endio;
1453
1454         ret = raid56_parity_recover(fs_info->fs_root, bio, page->recover->bbio,
1455                                     page->recover->map_length,
1456                                     page->mirror_num, 0);
1457         if (ret)
1458                 return ret;
1459
1460         wait_for_completion(&done.event);
1461         if (done.error)
1462                 return -EIO;
1463
1464         return 0;
1465 }
1466
1467 /*
1468  * this function will check the on disk data for checksum errors, header
1469  * errors and read I/O errors. If any I/O errors happen, the exact pages
1470  * which are errored are marked as being bad. The goal is to enable scrub
1471  * to take those pages that are not errored from all the mirrors so that
1472  * the pages that are errored in the just handled mirror can be repaired.
1473  */
1474 static void scrub_recheck_block(struct btrfs_fs_info *fs_info,
1475                                 struct scrub_block *sblock,
1476                                 int retry_failed_mirror)
1477 {
1478         int page_num;
1479
1480         sblock->no_io_error_seen = 1;
1481
1482         for (page_num = 0; page_num < sblock->page_count; page_num++) {
1483                 struct bio *bio;
1484                 struct scrub_page *page = sblock->pagev[page_num];
1485
1486                 if (page->dev->bdev == NULL) {
1487                         page->io_error = 1;
1488                         sblock->no_io_error_seen = 0;
1489                         continue;
1490                 }
1491
1492                 WARN_ON(!page->page);
1493                 bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
1494                 if (!bio) {
1495                         page->io_error = 1;
1496                         sblock->no_io_error_seen = 0;
1497                         continue;
1498                 }
1499                 bio->bi_bdev = page->dev->bdev;
1500
1501                 bio_add_page(bio, page->page, PAGE_SIZE, 0);
1502                 if (!retry_failed_mirror && scrub_is_page_on_raid56(page)) {
1503                         if (scrub_submit_raid56_bio_wait(fs_info, bio, page))
1504                                 sblock->no_io_error_seen = 0;
1505                 } else {
1506                         bio->bi_iter.bi_sector = page->physical >> 9;
1507
1508                         if (btrfsic_submit_bio_wait(READ, bio))
1509                                 sblock->no_io_error_seen = 0;
1510                 }
1511
1512                 bio_put(bio);
1513         }
1514
1515         if (sblock->no_io_error_seen)
1516                 scrub_recheck_block_checksum(sblock);
1517 }
1518
1519 static inline int scrub_check_fsid(u8 fsid[],
1520                                    struct scrub_page *spage)
1521 {
1522         struct btrfs_fs_devices *fs_devices = spage->dev->fs_devices;
1523         int ret;
1524
1525         ret = memcmp(fsid, fs_devices->fsid, BTRFS_UUID_SIZE);
1526         return !ret;
1527 }
1528
1529 static void scrub_recheck_block_checksum(struct scrub_block *sblock)
1530 {
1531         sblock->header_error = 0;
1532         sblock->checksum_error = 0;
1533         sblock->generation_error = 0;
1534
1535         if (sblock->pagev[0]->flags & BTRFS_EXTENT_FLAG_DATA)
1536                 scrub_checksum_data(sblock);
1537         else
1538                 scrub_checksum_tree_block(sblock);
1539 }
1540
1541 static int scrub_repair_block_from_good_copy(struct scrub_block *sblock_bad,
1542                                              struct scrub_block *sblock_good)
1543 {
1544         int page_num;
1545         int ret = 0;
1546
1547         for (page_num = 0; page_num < sblock_bad->page_count; page_num++) {
1548                 int ret_sub;
1549
1550                 ret_sub = scrub_repair_page_from_good_copy(sblock_bad,
1551                                                            sblock_good,
1552                                                            page_num, 1);
1553                 if (ret_sub)
1554                         ret = ret_sub;
1555         }
1556
1557         return ret;
1558 }
1559
1560 static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
1561                                             struct scrub_block *sblock_good,
1562                                             int page_num, int force_write)
1563 {
1564         struct scrub_page *page_bad = sblock_bad->pagev[page_num];
1565         struct scrub_page *page_good = sblock_good->pagev[page_num];
1566
1567         BUG_ON(page_bad->page == NULL);
1568         BUG_ON(page_good->page == NULL);
1569         if (force_write || sblock_bad->header_error ||
1570             sblock_bad->checksum_error || page_bad->io_error) {
1571                 struct bio *bio;
1572                 int ret;
1573
1574                 if (!page_bad->dev->bdev) {
1575                         btrfs_warn_rl(sblock_bad->sctx->dev_root->fs_info,
1576                                 "scrub_repair_page_from_good_copy(bdev == NULL) "
1577                                 "is unexpected");
1578                         return -EIO;
1579                 }
1580
1581                 bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
1582                 if (!bio)
1583                         return -EIO;
1584                 bio->bi_bdev = page_bad->dev->bdev;
1585                 bio->bi_iter.bi_sector = page_bad->physical >> 9;
1586
1587                 ret = bio_add_page(bio, page_good->page, PAGE_SIZE, 0);
1588                 if (PAGE_SIZE != ret) {
1589                         bio_put(bio);
1590                         return -EIO;
1591                 }
1592
1593                 if (btrfsic_submit_bio_wait(WRITE, bio)) {
1594                         btrfs_dev_stat_inc_and_print(page_bad->dev,
1595                                 BTRFS_DEV_STAT_WRITE_ERRS);
1596                         btrfs_dev_replace_stats_inc(
1597                                 &sblock_bad->sctx->dev_root->fs_info->
1598                                 dev_replace.num_write_errors);
1599                         bio_put(bio);
1600                         return -EIO;
1601                 }
1602                 bio_put(bio);
1603         }
1604
1605         return 0;
1606 }
1607
1608 static void scrub_write_block_to_dev_replace(struct scrub_block *sblock)
1609 {
1610         int page_num;
1611
1612         /*
1613          * This block is used for the check of the parity on the source device,
1614          * so the data needn't be written into the destination device.
1615          */
1616         if (sblock->sparity)
1617                 return;
1618
1619         for (page_num = 0; page_num < sblock->page_count; page_num++) {
1620                 int ret;
1621
1622                 ret = scrub_write_page_to_dev_replace(sblock, page_num);
1623                 if (ret)
1624                         btrfs_dev_replace_stats_inc(
1625                                 &sblock->sctx->dev_root->fs_info->dev_replace.
1626                                 num_write_errors);
1627         }
1628 }
1629
1630 static int scrub_write_page_to_dev_replace(struct scrub_block *sblock,
1631                                            int page_num)
1632 {
1633         struct scrub_page *spage = sblock->pagev[page_num];
1634
1635         BUG_ON(spage->page == NULL);
1636         if (spage->io_error) {
1637                 void *mapped_buffer = kmap_atomic(spage->page);
1638
1639                 memset(mapped_buffer, 0, PAGE_CACHE_SIZE);
1640                 flush_dcache_page(spage->page);
1641                 kunmap_atomic(mapped_buffer);
1642         }
1643         return scrub_add_page_to_wr_bio(sblock->sctx, spage);
1644 }
1645
1646 static int scrub_add_page_to_wr_bio(struct scrub_ctx *sctx,
1647                                     struct scrub_page *spage)
1648 {
1649         struct scrub_wr_ctx *wr_ctx = &sctx->wr_ctx;
1650         struct scrub_bio *sbio;
1651         int ret;
1652
1653         mutex_lock(&wr_ctx->wr_lock);
1654 again:
1655         if (!wr_ctx->wr_curr_bio) {
1656                 wr_ctx->wr_curr_bio = kzalloc(sizeof(*wr_ctx->wr_curr_bio),
1657                                               GFP_NOFS);
1658                 if (!wr_ctx->wr_curr_bio) {
1659                         mutex_unlock(&wr_ctx->wr_lock);
1660                         return -ENOMEM;
1661                 }
1662                 wr_ctx->wr_curr_bio->sctx = sctx;
1663                 wr_ctx->wr_curr_bio->page_count = 0;
1664         }
1665         sbio = wr_ctx->wr_curr_bio;
1666         if (sbio->page_count == 0) {
1667                 struct bio *bio;
1668
1669                 sbio->physical = spage->physical_for_dev_replace;
1670                 sbio->logical = spage->logical;
1671                 sbio->dev = wr_ctx->tgtdev;
1672                 bio = sbio->bio;
1673                 if (!bio) {
1674                         bio = btrfs_io_bio_alloc(GFP_NOFS, wr_ctx->pages_per_wr_bio);
1675                         if (!bio) {
1676                                 mutex_unlock(&wr_ctx->wr_lock);
1677                                 return -ENOMEM;
1678                         }
1679                         sbio->bio = bio;
1680                 }
1681
1682                 bio->bi_private = sbio;
1683                 bio->bi_end_io = scrub_wr_bio_end_io;
1684                 bio->bi_bdev = sbio->dev->bdev;
1685                 bio->bi_iter.bi_sector = sbio->physical >> 9;
1686                 sbio->err = 0;
1687         } else if (sbio->physical + sbio->page_count * PAGE_SIZE !=
1688                    spage->physical_for_dev_replace ||
1689                    sbio->logical + sbio->page_count * PAGE_SIZE !=
1690                    spage->logical) {
1691                 scrub_wr_submit(sctx);
1692                 goto again;
1693         }
1694
1695         ret = bio_add_page(sbio->bio, spage->page, PAGE_SIZE, 0);
1696         if (ret != PAGE_SIZE) {
1697                 if (sbio->page_count < 1) {
1698                         bio_put(sbio->bio);
1699                         sbio->bio = NULL;
1700                         mutex_unlock(&wr_ctx->wr_lock);
1701                         return -EIO;
1702                 }
1703                 scrub_wr_submit(sctx);
1704                 goto again;
1705         }
1706
1707         sbio->pagev[sbio->page_count] = spage;
1708         scrub_page_get(spage);
1709         sbio->page_count++;
1710         if (sbio->page_count == wr_ctx->pages_per_wr_bio)
1711                 scrub_wr_submit(sctx);
1712         mutex_unlock(&wr_ctx->wr_lock);
1713
1714         return 0;
1715 }
1716
1717 static void scrub_wr_submit(struct scrub_ctx *sctx)
1718 {
1719         struct scrub_wr_ctx *wr_ctx = &sctx->wr_ctx;
1720         struct scrub_bio *sbio;
1721
1722         if (!wr_ctx->wr_curr_bio)
1723                 return;
1724
1725         sbio = wr_ctx->wr_curr_bio;
1726         wr_ctx->wr_curr_bio = NULL;
1727         WARN_ON(!sbio->bio->bi_bdev);
1728         scrub_pending_bio_inc(sctx);
1729         /* process all writes in a single worker thread. Then the block layer
1730          * orders the requests before sending them to the driver which
1731          * doubled the write performance on spinning disks when measured
1732          * with Linux 3.5 */
1733         btrfsic_submit_bio(WRITE, sbio->bio);
1734 }
1735
1736 static void scrub_wr_bio_end_io(struct bio *bio)
1737 {
1738         struct scrub_bio *sbio = bio->bi_private;
1739         struct btrfs_fs_info *fs_info = sbio->dev->dev_root->fs_info;
1740
1741         sbio->err = bio->bi_error;
1742         sbio->bio = bio;
1743
1744         btrfs_init_work(&sbio->work, btrfs_scrubwrc_helper,
1745                          scrub_wr_bio_end_io_worker, NULL, NULL);
1746         btrfs_queue_work(fs_info->scrub_wr_completion_workers, &sbio->work);
1747 }
1748
1749 static void scrub_wr_bio_end_io_worker(struct btrfs_work *work)
1750 {
1751         struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
1752         struct scrub_ctx *sctx = sbio->sctx;
1753         int i;
1754
1755         WARN_ON(sbio->page_count > SCRUB_PAGES_PER_WR_BIO);
1756         if (sbio->err) {
1757                 struct btrfs_dev_replace *dev_replace =
1758                         &sbio->sctx->dev_root->fs_info->dev_replace;
1759
1760                 for (i = 0; i < sbio->page_count; i++) {
1761                         struct scrub_page *spage = sbio->pagev[i];
1762
1763                         spage->io_error = 1;
1764                         btrfs_dev_replace_stats_inc(&dev_replace->
1765                                                     num_write_errors);
1766                 }
1767         }
1768
1769         for (i = 0; i < sbio->page_count; i++)
1770                 scrub_page_put(sbio->pagev[i]);
1771
1772         bio_put(sbio->bio);
1773         kfree(sbio);
1774         scrub_pending_bio_dec(sctx);
1775 }
1776
1777 static int scrub_checksum(struct scrub_block *sblock)
1778 {
1779         u64 flags;
1780         int ret;
1781
1782         /*
1783          * No need to initialize these stats currently,
1784          * because this function only use return value
1785          * instead of these stats value.
1786          *
1787          * Todo:
1788          * always use stats
1789          */
1790         sblock->header_error = 0;
1791         sblock->generation_error = 0;
1792         sblock->checksum_error = 0;
1793
1794         WARN_ON(sblock->page_count < 1);
1795         flags = sblock->pagev[0]->flags;
1796         ret = 0;
1797         if (flags & BTRFS_EXTENT_FLAG_DATA)
1798                 ret = scrub_checksum_data(sblock);
1799         else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1800                 ret = scrub_checksum_tree_block(sblock);
1801         else if (flags & BTRFS_EXTENT_FLAG_SUPER)
1802                 (void)scrub_checksum_super(sblock);
1803         else
1804                 WARN_ON(1);
1805         if (ret)
1806                 scrub_handle_errored_block(sblock);
1807
1808         return ret;
1809 }
1810
1811 static int scrub_checksum_data(struct scrub_block *sblock)
1812 {
1813         struct scrub_ctx *sctx = sblock->sctx;
1814         u8 csum[BTRFS_CSUM_SIZE];
1815         u8 *on_disk_csum;
1816         struct page *page;
1817         void *buffer;
1818         u32 crc = ~(u32)0;
1819         u64 len;
1820         int index;
1821
1822         BUG_ON(sblock->page_count < 1);
1823         if (!sblock->pagev[0]->have_csum)
1824                 return 0;
1825
1826         on_disk_csum = sblock->pagev[0]->csum;
1827         page = sblock->pagev[0]->page;
1828         buffer = kmap_atomic(page);
1829
1830         len = sctx->sectorsize;
1831         index = 0;
1832         for (;;) {
1833                 u64 l = min_t(u64, len, PAGE_SIZE);
1834
1835                 crc = btrfs_csum_data(buffer, crc, l);
1836                 kunmap_atomic(buffer);
1837                 len -= l;
1838                 if (len == 0)
1839                         break;
1840                 index++;
1841                 BUG_ON(index >= sblock->page_count);
1842                 BUG_ON(!sblock->pagev[index]->page);
1843                 page = sblock->pagev[index]->page;
1844                 buffer = kmap_atomic(page);
1845         }
1846
1847         btrfs_csum_final(crc, csum);
1848         if (memcmp(csum, on_disk_csum, sctx->csum_size))
1849                 sblock->checksum_error = 1;
1850
1851         return sblock->checksum_error;
1852 }
1853
1854 static int scrub_checksum_tree_block(struct scrub_block *sblock)
1855 {
1856         struct scrub_ctx *sctx = sblock->sctx;
1857         struct btrfs_header *h;
1858         struct btrfs_root *root = sctx->dev_root;
1859         struct btrfs_fs_info *fs_info = root->fs_info;
1860         u8 calculated_csum[BTRFS_CSUM_SIZE];
1861         u8 on_disk_csum[BTRFS_CSUM_SIZE];
1862         struct page *page;
1863         void *mapped_buffer;
1864         u64 mapped_size;
1865         void *p;
1866         u32 crc = ~(u32)0;
1867         u64 len;
1868         int index;
1869
1870         BUG_ON(sblock->page_count < 1);
1871         page = sblock->pagev[0]->page;
1872         mapped_buffer = kmap_atomic(page);
1873         h = (struct btrfs_header *)mapped_buffer;
1874         memcpy(on_disk_csum, h->csum, sctx->csum_size);
1875
1876         /*
1877          * we don't use the getter functions here, as we
1878          * a) don't have an extent buffer and
1879          * b) the page is already kmapped
1880          */
1881         if (sblock->pagev[0]->logical != btrfs_stack_header_bytenr(h))
1882                 sblock->header_error = 1;
1883
1884         if (sblock->pagev[0]->generation != btrfs_stack_header_generation(h)) {
1885                 sblock->header_error = 1;
1886                 sblock->generation_error = 1;
1887         }
1888
1889         if (!scrub_check_fsid(h->fsid, sblock->pagev[0]))
1890                 sblock->header_error = 1;
1891
1892         if (memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
1893                    BTRFS_UUID_SIZE))
1894                 sblock->header_error = 1;
1895
1896         len = sctx->nodesize - BTRFS_CSUM_SIZE;
1897         mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE;
1898         p = ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE;
1899         index = 0;
1900         for (;;) {
1901                 u64 l = min_t(u64, len, mapped_size);
1902
1903                 crc = btrfs_csum_data(p, crc, l);
1904                 kunmap_atomic(mapped_buffer);
1905                 len -= l;
1906                 if (len == 0)
1907                         break;
1908                 index++;
1909                 BUG_ON(index >= sblock->page_count);
1910                 BUG_ON(!sblock->pagev[index]->page);
1911                 page = sblock->pagev[index]->page;
1912                 mapped_buffer = kmap_atomic(page);
1913                 mapped_size = PAGE_SIZE;
1914                 p = mapped_buffer;
1915         }
1916
1917         btrfs_csum_final(crc, calculated_csum);
1918         if (memcmp(calculated_csum, on_disk_csum, sctx->csum_size))
1919                 sblock->checksum_error = 1;
1920
1921         return sblock->header_error || sblock->checksum_error;
1922 }
1923
1924 static int scrub_checksum_super(struct scrub_block *sblock)
1925 {
1926         struct btrfs_super_block *s;
1927         struct scrub_ctx *sctx = sblock->sctx;
1928         u8 calculated_csum[BTRFS_CSUM_SIZE];
1929         u8 on_disk_csum[BTRFS_CSUM_SIZE];
1930         struct page *page;
1931         void *mapped_buffer;
1932         u64 mapped_size;
1933         void *p;
1934         u32 crc = ~(u32)0;
1935         int fail_gen = 0;
1936         int fail_cor = 0;
1937         u64 len;
1938         int index;
1939
1940         BUG_ON(sblock->page_count < 1);
1941         page = sblock->pagev[0]->page;
1942         mapped_buffer = kmap_atomic(page);
1943         s = (struct btrfs_super_block *)mapped_buffer;
1944         memcpy(on_disk_csum, s->csum, sctx->csum_size);
1945
1946         if (sblock->pagev[0]->logical != btrfs_super_bytenr(s))
1947                 ++fail_cor;
1948
1949         if (sblock->pagev[0]->generation != btrfs_super_generation(s))
1950                 ++fail_gen;
1951
1952         if (!scrub_check_fsid(s->fsid, sblock->pagev[0]))
1953                 ++fail_cor;
1954
1955         len = BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE;
1956         mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE;
1957         p = ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE;
1958         index = 0;
1959         for (;;) {
1960                 u64 l = min_t(u64, len, mapped_size);
1961
1962                 crc = btrfs_csum_data(p, crc, l);
1963                 kunmap_atomic(mapped_buffer);
1964                 len -= l;
1965                 if (len == 0)
1966                         break;
1967                 index++;
1968                 BUG_ON(index >= sblock->page_count);
1969                 BUG_ON(!sblock->pagev[index]->page);
1970                 page = sblock->pagev[index]->page;
1971                 mapped_buffer = kmap_atomic(page);
1972                 mapped_size = PAGE_SIZE;
1973                 p = mapped_buffer;
1974         }
1975
1976         btrfs_csum_final(crc, calculated_csum);
1977         if (memcmp(calculated_csum, on_disk_csum, sctx->csum_size))
1978                 ++fail_cor;
1979
1980         if (fail_cor + fail_gen) {
1981                 /*
1982                  * if we find an error in a super block, we just report it.
1983                  * They will get written with the next transaction commit
1984                  * anyway
1985                  */
1986                 spin_lock(&sctx->stat_lock);
1987                 ++sctx->stat.super_errors;
1988                 spin_unlock(&sctx->stat_lock);
1989                 if (fail_cor)
1990                         btrfs_dev_stat_inc_and_print(sblock->pagev[0]->dev,
1991                                 BTRFS_DEV_STAT_CORRUPTION_ERRS);
1992                 else
1993                         btrfs_dev_stat_inc_and_print(sblock->pagev[0]->dev,
1994                                 BTRFS_DEV_STAT_GENERATION_ERRS);
1995         }
1996
1997         return fail_cor + fail_gen;
1998 }
1999
2000 static void scrub_block_get(struct scrub_block *sblock)
2001 {
2002         atomic_inc(&sblock->refs);
2003 }
2004
2005 static void scrub_block_put(struct scrub_block *sblock)
2006 {
2007         if (atomic_dec_and_test(&sblock->refs)) {
2008                 int i;
2009
2010                 if (sblock->sparity)
2011                         scrub_parity_put(sblock->sparity);
2012
2013                 for (i = 0; i < sblock->page_count; i++)
2014                         scrub_page_put(sblock->pagev[i]);
2015                 kfree(sblock);
2016         }
2017 }
2018
2019 static void scrub_page_get(struct scrub_page *spage)
2020 {
2021         atomic_inc(&spage->refs);
2022 }
2023
2024 static void scrub_page_put(struct scrub_page *spage)
2025 {
2026         if (atomic_dec_and_test(&spage->refs)) {
2027                 if (spage->page)
2028                         __free_page(spage->page);
2029                 kfree(spage);
2030         }
2031 }
2032
2033 static void scrub_submit(struct scrub_ctx *sctx)
2034 {
2035         struct scrub_bio *sbio;
2036
2037         if (sctx->curr == -1)
2038                 return;
2039
2040         sbio = sctx->bios[sctx->curr];
2041         sctx->curr = -1;
2042         scrub_pending_bio_inc(sctx);
2043         btrfsic_submit_bio(READ, sbio->bio);
2044 }
2045
2046 static int scrub_add_page_to_rd_bio(struct scrub_ctx *sctx,
2047                                     struct scrub_page *spage)
2048 {
2049         struct scrub_block *sblock = spage->sblock;
2050         struct scrub_bio *sbio;
2051         int ret;
2052
2053 again:
2054         /*
2055          * grab a fresh bio or wait for one to become available
2056          */
2057         while (sctx->curr == -1) {
2058                 spin_lock(&sctx->list_lock);
2059                 sctx->curr = sctx->first_free;
2060                 if (sctx->curr != -1) {
2061                         sctx->first_free = sctx->bios[sctx->curr]->next_free;
2062                         sctx->bios[sctx->curr]->next_free = -1;
2063                         sctx->bios[sctx->curr]->page_count = 0;
2064                         spin_unlock(&sctx->list_lock);
2065                 } else {
2066                         spin_unlock(&sctx->list_lock);
2067                         wait_event(sctx->list_wait, sctx->first_free != -1);
2068                 }
2069         }
2070         sbio = sctx->bios[sctx->curr];
2071         if (sbio->page_count == 0) {
2072                 struct bio *bio;
2073
2074                 sbio->physical = spage->physical;
2075                 sbio->logical = spage->logical;
2076                 sbio->dev = spage->dev;
2077                 bio = sbio->bio;
2078                 if (!bio) {
2079                         bio = btrfs_io_bio_alloc(GFP_NOFS, sctx->pages_per_rd_bio);
2080                         if (!bio)
2081                                 return -ENOMEM;
2082                         sbio->bio = bio;
2083                 }
2084
2085                 bio->bi_private = sbio;
2086                 bio->bi_end_io = scrub_bio_end_io;
2087                 bio->bi_bdev = sbio->dev->bdev;
2088                 bio->bi_iter.bi_sector = sbio->physical >> 9;
2089                 sbio->err = 0;
2090         } else if (sbio->physical + sbio->page_count * PAGE_SIZE !=
2091                    spage->physical ||
2092                    sbio->logical + sbio->page_count * PAGE_SIZE !=
2093                    spage->logical ||
2094                    sbio->dev != spage->dev) {
2095                 scrub_submit(sctx);
2096                 goto again;
2097         }
2098
2099         sbio->pagev[sbio->page_count] = spage;
2100         ret = bio_add_page(sbio->bio, spage->page, PAGE_SIZE, 0);
2101         if (ret != PAGE_SIZE) {
2102                 if (sbio->page_count < 1) {
2103                         bio_put(sbio->bio);
2104                         sbio->bio = NULL;
2105                         return -EIO;
2106                 }
2107                 scrub_submit(sctx);
2108                 goto again;
2109         }
2110
2111         scrub_block_get(sblock); /* one for the page added to the bio */
2112         atomic_inc(&sblock->outstanding_pages);
2113         sbio->page_count++;
2114         if (sbio->page_count == sctx->pages_per_rd_bio)
2115                 scrub_submit(sctx);
2116
2117         return 0;
2118 }
2119
2120 static void scrub_missing_raid56_end_io(struct bio *bio)
2121 {
2122         struct scrub_block *sblock = bio->bi_private;
2123         struct btrfs_fs_info *fs_info = sblock->sctx->dev_root->fs_info;
2124
2125         if (bio->bi_error)
2126                 sblock->no_io_error_seen = 0;
2127
2128         btrfs_queue_work(fs_info->scrub_workers, &sblock->work);
2129 }
2130
2131 static void scrub_missing_raid56_worker(struct btrfs_work *work)
2132 {
2133         struct scrub_block *sblock = container_of(work, struct scrub_block, work);
2134         struct scrub_ctx *sctx = sblock->sctx;
2135         u64 logical;
2136         struct btrfs_device *dev;
2137
2138         logical = sblock->pagev[0]->logical;
2139         dev = sblock->pagev[0]->dev;
2140
2141         if (sblock->no_io_error_seen)
2142                 scrub_recheck_block_checksum(sblock);
2143
2144         if (!sblock->no_io_error_seen) {
2145                 spin_lock(&sctx->stat_lock);
2146                 sctx->stat.read_errors++;
2147                 spin_unlock(&sctx->stat_lock);
2148                 btrfs_err_rl_in_rcu(sctx->dev_root->fs_info,
2149                         "IO error rebuilding logical %llu for dev %s",
2150                         logical, rcu_str_deref(dev->name));
2151         } else if (sblock->header_error || sblock->checksum_error) {
2152                 spin_lock(&sctx->stat_lock);
2153                 sctx->stat.uncorrectable_errors++;
2154                 spin_unlock(&sctx->stat_lock);
2155                 btrfs_err_rl_in_rcu(sctx->dev_root->fs_info,
2156                         "failed to rebuild valid logical %llu for dev %s",
2157                         logical, rcu_str_deref(dev->name));
2158         } else {
2159                 scrub_write_block_to_dev_replace(sblock);
2160         }
2161
2162         scrub_block_put(sblock);
2163
2164         if (sctx->is_dev_replace &&
2165             atomic_read(&sctx->wr_ctx.flush_all_writes)) {
2166                 mutex_lock(&sctx->wr_ctx.wr_lock);
2167                 scrub_wr_submit(sctx);
2168                 mutex_unlock(&sctx->wr_ctx.wr_lock);
2169         }
2170
2171         scrub_pending_bio_dec(sctx);
2172 }
2173
2174 static void scrub_missing_raid56_pages(struct scrub_block *sblock)
2175 {
2176         struct scrub_ctx *sctx = sblock->sctx;
2177         struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;
2178         u64 length = sblock->page_count * PAGE_SIZE;
2179         u64 logical = sblock->pagev[0]->logical;
2180         struct btrfs_bio *bbio;
2181         struct bio *bio;
2182         struct btrfs_raid_bio *rbio;
2183         int ret;
2184         int i;
2185
2186         ret = btrfs_map_sblock(fs_info, REQ_GET_READ_MIRRORS, logical, &length,
2187                                &bbio, 0, 1);
2188         if (ret || !bbio || !bbio->raid_map)
2189                 goto bbio_out;
2190
2191         if (WARN_ON(!sctx->is_dev_replace ||
2192                     !(bbio->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK))) {
2193                 /*
2194                  * We shouldn't be scrubbing a missing device. Even for dev
2195                  * replace, we should only get here for RAID 5/6. We either
2196                  * managed to mount something with no mirrors remaining or
2197                  * there's a bug in scrub_remap_extent()/btrfs_map_block().
2198                  */
2199                 goto bbio_out;
2200         }
2201
2202         bio = btrfs_io_bio_alloc(GFP_NOFS, 0);
2203         if (!bio)
2204                 goto bbio_out;
2205
2206         bio->bi_iter.bi_sector = logical >> 9;
2207         bio->bi_private = sblock;
2208         bio->bi_end_io = scrub_missing_raid56_end_io;
2209
2210         rbio = raid56_alloc_missing_rbio(sctx->dev_root, bio, bbio, length);
2211         if (!rbio)
2212                 goto rbio_out;
2213
2214         for (i = 0; i < sblock->page_count; i++) {
2215                 struct scrub_page *spage = sblock->pagev[i];
2216
2217                 raid56_add_scrub_pages(rbio, spage->page, spage->logical);
2218         }
2219
2220         btrfs_init_work(&sblock->work, btrfs_scrub_helper,
2221                         scrub_missing_raid56_worker, NULL, NULL);
2222         scrub_block_get(sblock);
2223         scrub_pending_bio_inc(sctx);
2224         raid56_submit_missing_rbio(rbio);
2225         return;
2226
2227 rbio_out:
2228         bio_put(bio);
2229 bbio_out:
2230         btrfs_put_bbio(bbio);
2231         spin_lock(&sctx->stat_lock);
2232         sctx->stat.malloc_errors++;
2233         spin_unlock(&sctx->stat_lock);
2234 }
2235
2236 static int scrub_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
2237                        u64 physical, struct btrfs_device *dev, u64 flags,
2238                        u64 gen, int mirror_num, u8 *csum, int force,
2239                        u64 physical_for_dev_replace)
2240 {
2241         struct scrub_block *sblock;
2242         int index;
2243
2244         sblock = kzalloc(sizeof(*sblock), GFP_NOFS);
2245         if (!sblock) {
2246                 spin_lock(&sctx->stat_lock);
2247                 sctx->stat.malloc_errors++;
2248                 spin_unlock(&sctx->stat_lock);
2249                 return -ENOMEM;
2250         }
2251
2252         /* one ref inside this function, plus one for each page added to
2253          * a bio later on */
2254         atomic_set(&sblock->refs, 1);
2255         sblock->sctx = sctx;
2256         sblock->no_io_error_seen = 1;
2257
2258         for (index = 0; len > 0; index++) {
2259                 struct scrub_page *spage;
2260                 u64 l = min_t(u64, len, PAGE_SIZE);
2261
2262                 spage = kzalloc(sizeof(*spage), GFP_NOFS);
2263                 if (!spage) {
2264 leave_nomem:
2265                         spin_lock(&sctx->stat_lock);
2266                         sctx->stat.malloc_errors++;
2267                         spin_unlock(&sctx->stat_lock);
2268                         scrub_block_put(sblock);
2269                         return -ENOMEM;
2270                 }
2271                 BUG_ON(index >= SCRUB_MAX_PAGES_PER_BLOCK);
2272                 scrub_page_get(spage);
2273                 sblock->pagev[index] = spage;
2274                 spage->sblock = sblock;
2275                 spage->dev = dev;
2276                 spage->flags = flags;
2277                 spage->generation = gen;
2278                 spage->logical = logical;
2279                 spage->physical = physical;
2280                 spage->physical_for_dev_replace = physical_for_dev_replace;
2281                 spage->mirror_num = mirror_num;
2282                 if (csum) {
2283                         spage->have_csum = 1;
2284                         memcpy(spage->csum, csum, sctx->csum_size);
2285                 } else {
2286                         spage->have_csum = 0;
2287                 }
2288                 sblock->page_count++;
2289                 spage->page = alloc_page(GFP_NOFS);
2290                 if (!spage->page)
2291                         goto leave_nomem;
2292                 len -= l;
2293                 logical += l;
2294                 physical += l;
2295                 physical_for_dev_replace += l;
2296         }
2297
2298         WARN_ON(sblock->page_count == 0);
2299         if (dev->missing) {
2300                 /*
2301                  * This case should only be hit for RAID 5/6 device replace. See
2302                  * the comment in scrub_missing_raid56_pages() for details.
2303                  */
2304                 scrub_missing_raid56_pages(sblock);
2305         } else {
2306                 for (index = 0; index < sblock->page_count; index++) {
2307                         struct scrub_page *spage = sblock->pagev[index];
2308                         int ret;
2309
2310                         ret = scrub_add_page_to_rd_bio(sctx, spage);
2311                         if (ret) {
2312                                 scrub_block_put(sblock);
2313                                 return ret;
2314                         }
2315                 }
2316
2317                 if (force)
2318                         scrub_submit(sctx);
2319         }
2320
2321         /* last one frees, either here or in bio completion for last page */
2322         scrub_block_put(sblock);
2323         return 0;
2324 }
2325
2326 static void scrub_bio_end_io(struct bio *bio)
2327 {
2328         struct scrub_bio *sbio = bio->bi_private;
2329         struct btrfs_fs_info *fs_info = sbio->dev->dev_root->fs_info;
2330
2331         sbio->err = bio->bi_error;
2332         sbio->bio = bio;
2333
2334         btrfs_queue_work(fs_info->scrub_workers, &sbio->work);
2335 }
2336
2337 static void scrub_bio_end_io_worker(struct btrfs_work *work)
2338 {
2339         struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
2340         struct scrub_ctx *sctx = sbio->sctx;
2341         int i;
2342
2343         BUG_ON(sbio->page_count > SCRUB_PAGES_PER_RD_BIO);
2344         if (sbio->err) {
2345                 for (i = 0; i < sbio->page_count; i++) {
2346                         struct scrub_page *spage = sbio->pagev[i];
2347
2348                         spage->io_error = 1;
2349                         spage->sblock->no_io_error_seen = 0;
2350                 }
2351         }
2352
2353         /* now complete the scrub_block items that have all pages completed */
2354         for (i = 0; i < sbio->page_count; i++) {
2355                 struct scrub_page *spage = sbio->pagev[i];
2356                 struct scrub_block *sblock = spage->sblock;
2357
2358                 if (atomic_dec_and_test(&sblock->outstanding_pages))
2359                         scrub_block_complete(sblock);
2360                 scrub_block_put(sblock);
2361         }
2362
2363         bio_put(sbio->bio);
2364         sbio->bio = NULL;
2365         spin_lock(&sctx->list_lock);
2366         sbio->next_free = sctx->first_free;
2367         sctx->first_free = sbio->index;
2368         spin_unlock(&sctx->list_lock);
2369
2370         if (sctx->is_dev_replace &&
2371             atomic_read(&sctx->wr_ctx.flush_all_writes)) {
2372                 mutex_lock(&sctx->wr_ctx.wr_lock);
2373                 scrub_wr_submit(sctx);
2374                 mutex_unlock(&sctx->wr_ctx.wr_lock);
2375         }
2376
2377         scrub_pending_bio_dec(sctx);
2378 }
2379
2380 static inline void __scrub_mark_bitmap(struct scrub_parity *sparity,
2381                                        unsigned long *bitmap,
2382                                        u64 start, u64 len)
2383 {
2384         u32 offset;
2385         int nsectors;
2386         int sectorsize = sparity->sctx->dev_root->sectorsize;
2387
2388         if (len >= sparity->stripe_len) {
2389                 bitmap_set(bitmap, 0, sparity->nsectors);
2390                 return;
2391         }
2392
2393         start -= sparity->logic_start;
2394         start = div_u64_rem(start, sparity->stripe_len, &offset);
2395         offset /= sectorsize;
2396         nsectors = (int)len / sectorsize;
2397
2398         if (offset + nsectors <= sparity->nsectors) {
2399                 bitmap_set(bitmap, offset, nsectors);
2400                 return;
2401         }
2402
2403         bitmap_set(bitmap, offset, sparity->nsectors - offset);
2404         bitmap_set(bitmap, 0, nsectors - (sparity->nsectors - offset));
2405 }
2406
2407 static inline void scrub_parity_mark_sectors_error(struct scrub_parity *sparity,
2408                                                    u64 start, u64 len)
2409 {
2410         __scrub_mark_bitmap(sparity, sparity->ebitmap, start, len);
2411 }
2412
2413 static inline void scrub_parity_mark_sectors_data(struct scrub_parity *sparity,
2414                                                   u64 start, u64 len)
2415 {
2416         __scrub_mark_bitmap(sparity, sparity->dbitmap, start, len);
2417 }
2418
2419 static void scrub_block_complete(struct scrub_block *sblock)
2420 {
2421         int corrupted = 0;
2422
2423         if (!sblock->no_io_error_seen) {
2424                 corrupted = 1;
2425                 scrub_handle_errored_block(sblock);
2426         } else {
2427                 /*
2428                  * if has checksum error, write via repair mechanism in
2429                  * dev replace case, otherwise write here in dev replace
2430                  * case.
2431                  */
2432                 corrupted = scrub_checksum(sblock);
2433                 if (!corrupted && sblock->sctx->is_dev_replace)
2434                         scrub_write_block_to_dev_replace(sblock);
2435         }
2436
2437         if (sblock->sparity && corrupted && !sblock->data_corrected) {
2438                 u64 start = sblock->pagev[0]->logical;
2439                 u64 end = sblock->pagev[sblock->page_count - 1]->logical +
2440                           PAGE_SIZE;
2441
2442                 scrub_parity_mark_sectors_error(sblock->sparity,
2443                                                 start, end - start);
2444         }
2445 }
2446
2447 static int scrub_find_csum(struct scrub_ctx *sctx, u64 logical, u8 *csum)
2448 {
2449         struct btrfs_ordered_sum *sum = NULL;
2450         unsigned long index;
2451         unsigned long num_sectors;
2452
2453         while (!list_empty(&sctx->csum_list)) {
2454                 sum = list_first_entry(&sctx->csum_list,
2455                                        struct btrfs_ordered_sum, list);
2456                 if (sum->bytenr > logical)
2457                         return 0;
2458                 if (sum->bytenr + sum->len > logical)
2459                         break;
2460
2461                 ++sctx->stat.csum_discards;
2462                 list_del(&sum->list);
2463                 kfree(sum);
2464                 sum = NULL;
2465         }
2466         if (!sum)
2467                 return 0;
2468
2469         index = ((u32)(logical - sum->bytenr)) / sctx->sectorsize;
2470         num_sectors = sum->len / sctx->sectorsize;
2471         memcpy(csum, sum->sums + index, sctx->csum_size);
2472         if (index == num_sectors - 1) {
2473                 list_del(&sum->list);
2474                 kfree(sum);
2475         }
2476         return 1;
2477 }
2478
2479 /* scrub extent tries to collect up to 64 kB for each bio */
2480 static int scrub_extent(struct scrub_ctx *sctx, u64 logical, u64 len,
2481                         u64 physical, struct btrfs_device *dev, u64 flags,
2482                         u64 gen, int mirror_num, u64 physical_for_dev_replace)
2483 {
2484         int ret;
2485         u8 csum[BTRFS_CSUM_SIZE];
2486         u32 blocksize;
2487
2488         if (flags & BTRFS_EXTENT_FLAG_DATA) {
2489                 blocksize = sctx->sectorsize;
2490                 spin_lock(&sctx->stat_lock);
2491                 sctx->stat.data_extents_scrubbed++;
2492                 sctx->stat.data_bytes_scrubbed += len;
2493                 spin_unlock(&sctx->stat_lock);
2494         } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
2495                 blocksize = sctx->nodesize;
2496                 spin_lock(&sctx->stat_lock);
2497                 sctx->stat.tree_extents_scrubbed++;
2498                 sctx->stat.tree_bytes_scrubbed += len;
2499                 spin_unlock(&sctx->stat_lock);
2500         } else {
2501                 blocksize = sctx->sectorsize;
2502                 WARN_ON(1);
2503         }
2504
2505         while (len) {
2506                 u64 l = min_t(u64, len, blocksize);
2507                 int have_csum = 0;
2508
2509                 if (flags & BTRFS_EXTENT_FLAG_DATA) {
2510                         /* push csums to sbio */
2511                         have_csum = scrub_find_csum(sctx, logical, csum);
2512                         if (have_csum == 0)
2513                                 ++sctx->stat.no_csum;
2514                         if (sctx->is_dev_replace && !have_csum) {
2515                                 ret = copy_nocow_pages(sctx, logical, l,
2516                                                        mirror_num,
2517                                                       physical_for_dev_replace);
2518                                 goto behind_scrub_pages;
2519                         }
2520                 }
2521                 ret = scrub_pages(sctx, logical, l, physical, dev, flags, gen,
2522                                   mirror_num, have_csum ? csum : NULL, 0,
2523                                   physical_for_dev_replace);
2524 behind_scrub_pages:
2525                 if (ret)
2526                         return ret;
2527                 len -= l;
2528                 logical += l;
2529                 physical += l;
2530                 physical_for_dev_replace += l;
2531         }
2532         return 0;
2533 }
2534
2535 static int scrub_pages_for_parity(struct scrub_parity *sparity,
2536                                   u64 logical, u64 len,
2537                                   u64 physical, struct btrfs_device *dev,
2538                                   u64 flags, u64 gen, int mirror_num, u8 *csum)
2539 {
2540         struct scrub_ctx *sctx = sparity->sctx;
2541         struct scrub_block *sblock;
2542         int index;
2543
2544         sblock = kzalloc(sizeof(*sblock), GFP_NOFS);
2545         if (!sblock) {
2546                 spin_lock(&sctx->stat_lock);
2547                 sctx->stat.malloc_errors++;
2548                 spin_unlock(&sctx->stat_lock);
2549                 return -ENOMEM;
2550         }
2551
2552         /* one ref inside this function, plus one for each page added to
2553          * a bio later on */
2554         atomic_set(&sblock->refs, 1);
2555         sblock->sctx = sctx;
2556         sblock->no_io_error_seen = 1;
2557         sblock->sparity = sparity;
2558         scrub_parity_get(sparity);
2559
2560         for (index = 0; len > 0; index++) {
2561                 struct scrub_page *spage;
2562                 u64 l = min_t(u64, len, PAGE_SIZE);
2563
2564                 spage = kzalloc(sizeof(*spage), GFP_NOFS);
2565                 if (!spage) {
2566 leave_nomem:
2567                         spin_lock(&sctx->stat_lock);
2568                         sctx->stat.malloc_errors++;
2569                         spin_unlock(&sctx->stat_lock);
2570                         scrub_block_put(sblock);
2571                         return -ENOMEM;
2572                 }
2573                 BUG_ON(index >= SCRUB_MAX_PAGES_PER_BLOCK);
2574                 /* For scrub block */
2575                 scrub_page_get(spage);
2576                 sblock->pagev[index] = spage;
2577                 /* For scrub parity */
2578                 scrub_page_get(spage);
2579                 list_add_tail(&spage->list, &sparity->spages);
2580                 spage->sblock = sblock;
2581                 spage->dev = dev;
2582                 spage->flags = flags;
2583                 spage->generation = gen;
2584                 spage->logical = logical;
2585                 spage->physical = physical;
2586                 spage->mirror_num = mirror_num;
2587                 if (csum) {
2588                         spage->have_csum = 1;
2589                         memcpy(spage->csum, csum, sctx->csum_size);
2590                 } else {
2591                         spage->have_csum = 0;
2592                 }
2593                 sblock->page_count++;
2594                 spage->page = alloc_page(GFP_NOFS);
2595                 if (!spage->page)
2596                         goto leave_nomem;
2597                 len -= l;
2598                 logical += l;
2599                 physical += l;
2600         }
2601
2602         WARN_ON(sblock->page_count == 0);
2603         for (index = 0; index < sblock->page_count; index++) {
2604                 struct scrub_page *spage = sblock->pagev[index];
2605                 int ret;
2606
2607                 ret = scrub_add_page_to_rd_bio(sctx, spage);
2608                 if (ret) {
2609                         scrub_block_put(sblock);
2610                         return ret;
2611                 }
2612         }
2613
2614         /* last one frees, either here or in bio completion for last page */
2615         scrub_block_put(sblock);
2616         return 0;
2617 }
2618
2619 static int scrub_extent_for_parity(struct scrub_parity *sparity,
2620                                    u64 logical, u64 len,
2621                                    u64 physical, struct btrfs_device *dev,
2622                                    u64 flags, u64 gen, int mirror_num)
2623 {
2624         struct scrub_ctx *sctx = sparity->sctx;
2625         int ret;
2626         u8 csum[BTRFS_CSUM_SIZE];
2627         u32 blocksize;
2628
2629         if (dev->missing) {
2630                 scrub_parity_mark_sectors_error(sparity, logical, len);
2631                 return 0;
2632         }
2633
2634         if (flags & BTRFS_EXTENT_FLAG_DATA) {
2635                 blocksize = sctx->sectorsize;
2636         } else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
2637                 blocksize = sctx->nodesize;
2638         } else {
2639                 blocksize = sctx->sectorsize;
2640                 WARN_ON(1);
2641         }
2642
2643         while (len) {
2644                 u64 l = min_t(u64, len, blocksize);
2645                 int have_csum = 0;
2646
2647                 if (flags & BTRFS_EXTENT_FLAG_DATA) {
2648                         /* push csums to sbio */
2649                         have_csum = scrub_find_csum(sctx, logical, csum);
2650                         if (have_csum == 0)
2651                                 goto skip;
2652                 }
2653                 ret = scrub_pages_for_parity(sparity, logical, l, physical, dev,
2654                                              flags, gen, mirror_num,
2655                                              have_csum ? csum : NULL);
2656                 if (ret)
2657                         return ret;
2658 skip:
2659                 len -= l;
2660                 logical += l;
2661                 physical += l;
2662         }
2663         return 0;
2664 }
2665
2666 /*
2667  * Given a physical address, this will calculate it's
2668  * logical offset. if this is a parity stripe, it will return
2669  * the most left data stripe's logical offset.
2670  *
2671  * return 0 if it is a data stripe, 1 means parity stripe.
2672  */
2673 static int get_raid56_logic_offset(u64 physical, int num,
2674                                    struct map_lookup *map, u64 *offset,
2675                                    u64 *stripe_start)
2676 {
2677         int i;
2678         int j = 0;
2679         u64 stripe_nr;
2680         u64 last_offset;
2681         u32 stripe_index;
2682         u32 rot;
2683
2684         last_offset = (physical - map->stripes[num].physical) *
2685                       nr_data_stripes(map);
2686         if (stripe_start)
2687                 *stripe_start = last_offset;
2688
2689         *offset = last_offset;
2690         for (i = 0; i < nr_data_stripes(map); i++) {
2691                 *offset = last_offset + i * map->stripe_len;
2692
2693                 stripe_nr = div_u64(*offset, map->stripe_len);
2694                 stripe_nr = div_u64(stripe_nr, nr_data_stripes(map));
2695
2696                 /* Work out the disk rotation on this stripe-set */
2697                 stripe_nr = div_u64_rem(stripe_nr, map->num_stripes, &rot);
2698                 /* calculate which stripe this data locates */
2699                 rot += i;
2700                 stripe_index = rot % map->num_stripes;
2701                 if (stripe_index == num)
2702                         return 0;
2703                 if (stripe_index < num)
2704                         j++;
2705         }
2706         *offset = last_offset + j * map->stripe_len;
2707         return 1;
2708 }
2709
2710 static void scrub_free_parity(struct scrub_parity *sparity)
2711 {
2712         struct scrub_ctx *sctx = sparity->sctx;
2713         struct scrub_page *curr, *next;
2714         int nbits;
2715
2716         nbits = bitmap_weight(sparity->ebitmap, sparity->nsectors);
2717         if (nbits) {
2718                 spin_lock(&sctx->stat_lock);
2719                 sctx->stat.read_errors += nbits;
2720                 sctx->stat.uncorrectable_errors += nbits;
2721                 spin_unlock(&sctx->stat_lock);
2722         }
2723
2724         list_for_each_entry_safe(curr, next, &sparity->spages, list) {
2725                 list_del_init(&curr->list);
2726                 scrub_page_put(curr);
2727         }
2728
2729         kfree(sparity);
2730 }
2731
2732 static void scrub_parity_bio_endio_worker(struct btrfs_work *work)
2733 {
2734         struct scrub_parity *sparity = container_of(work, struct scrub_parity,
2735                                                     work);
2736         struct scrub_ctx *sctx = sparity->sctx;
2737
2738         scrub_free_parity(sparity);
2739         scrub_pending_bio_dec(sctx);
2740 }
2741
2742 static void scrub_parity_bio_endio(struct bio *bio)
2743 {
2744         struct scrub_parity *sparity = (struct scrub_parity *)bio->bi_private;
2745
2746         if (bio->bi_error)
2747                 bitmap_or(sparity->ebitmap, sparity->ebitmap, sparity->dbitmap,
2748                           sparity->nsectors);
2749
2750         bio_put(bio);
2751
2752         btrfs_init_work(&sparity->work, btrfs_scrubparity_helper,
2753                         scrub_parity_bio_endio_worker, NULL, NULL);
2754         btrfs_queue_work(sparity->sctx->dev_root->fs_info->scrub_parity_workers,
2755                          &sparity->work);
2756 }
2757
2758 static void scrub_parity_check_and_repair(struct scrub_parity *sparity)
2759 {
2760         struct scrub_ctx *sctx = sparity->sctx;
2761         struct bio *bio;
2762         struct btrfs_raid_bio *rbio;
2763         struct scrub_page *spage;
2764         struct btrfs_bio *bbio = NULL;
2765         u64 length;
2766         int ret;
2767
2768         if (!bitmap_andnot(sparity->dbitmap, sparity->dbitmap, sparity->ebitmap,
2769                            sparity->nsectors))
2770                 goto out;
2771
2772         length = sparity->logic_end - sparity->logic_start;
2773         ret = btrfs_map_sblock(sctx->dev_root->fs_info, WRITE,
2774                                sparity->logic_start,
2775                                &length, &bbio, 0, 1);
2776         if (ret || !bbio || !bbio->raid_map)
2777                 goto bbio_out;
2778
2779         bio = btrfs_io_bio_alloc(GFP_NOFS, 0);
2780         if (!bio)
2781                 goto bbio_out;
2782
2783         bio->bi_iter.bi_sector = sparity->logic_start >> 9;
2784         bio->bi_private = sparity;
2785         bio->bi_end_io = scrub_parity_bio_endio;
2786
2787         rbio = raid56_parity_alloc_scrub_rbio(sctx->dev_root, bio, bbio,
2788                                               length, sparity->scrub_dev,
2789                                               sparity->dbitmap,
2790                                               sparity->nsectors);
2791         if (!rbio)
2792                 goto rbio_out;
2793
2794         list_for_each_entry(spage, &sparity->spages, list)
2795                 raid56_add_scrub_pages(rbio, spage->page, spage->logical);
2796
2797         scrub_pending_bio_inc(sctx);
2798         raid56_parity_submit_scrub_rbio(rbio);
2799         return;
2800
2801 rbio_out:
2802         bio_put(bio);
2803 bbio_out:
2804         btrfs_put_bbio(bbio);
2805         bitmap_or(sparity->ebitmap, sparity->ebitmap, sparity->dbitmap,
2806                   sparity->nsectors);
2807         spin_lock(&sctx->stat_lock);
2808         sctx->stat.malloc_errors++;
2809         spin_unlock(&sctx->stat_lock);
2810 out:
2811         scrub_free_parity(sparity);
2812 }
2813
2814 static inline int scrub_calc_parity_bitmap_len(int nsectors)
2815 {
2816         return DIV_ROUND_UP(nsectors, BITS_PER_LONG) * (BITS_PER_LONG / 8);
2817 }
2818
2819 static void scrub_parity_get(struct scrub_parity *sparity)
2820 {
2821         atomic_inc(&sparity->refs);
2822 }
2823
2824 static void scrub_parity_put(struct scrub_parity *sparity)
2825 {
2826         if (!atomic_dec_and_test(&sparity->refs))
2827                 return;
2828
2829         scrub_parity_check_and_repair(sparity);
2830 }
2831
2832 static noinline_for_stack int scrub_raid56_parity(struct scrub_ctx *sctx,
2833                                                   struct map_lookup *map,
2834                                                   struct btrfs_device *sdev,
2835                                                   struct btrfs_path *path,
2836                                                   u64 logic_start,
2837                                                   u64 logic_end)
2838 {
2839         struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;
2840         struct btrfs_root *root = fs_info->extent_root;
2841         struct btrfs_root *csum_root = fs_info->csum_root;
2842         struct btrfs_extent_item *extent;
2843         struct btrfs_bio *bbio = NULL;
2844         u64 flags;
2845         int ret;
2846         int slot;
2847         struct extent_buffer *l;
2848         struct btrfs_key key;
2849         u64 generation;
2850         u64 extent_logical;
2851         u64 extent_physical;
2852         u64 extent_len;
2853         u64 mapped_length;
2854         struct btrfs_device *extent_dev;
2855         struct scrub_parity *sparity;
2856         int nsectors;
2857         int bitmap_len;
2858         int extent_mirror_num;
2859         int stop_loop = 0;
2860
2861         nsectors = map->stripe_len / root->sectorsize;
2862         bitmap_len = scrub_calc_parity_bitmap_len(nsectors);
2863         sparity = kzalloc(sizeof(struct scrub_parity) + 2 * bitmap_len,
2864                           GFP_NOFS);
2865         if (!sparity) {
2866                 spin_lock(&sctx->stat_lock);
2867                 sctx->stat.malloc_errors++;
2868                 spin_unlock(&sctx->stat_lock);
2869                 return -ENOMEM;
2870         }
2871
2872         sparity->stripe_len = map->stripe_len;
2873         sparity->nsectors = nsectors;
2874         sparity->sctx = sctx;
2875         sparity->scrub_dev = sdev;
2876         sparity->logic_start = logic_start;
2877         sparity->logic_end = logic_end;
2878         atomic_set(&sparity->refs, 1);
2879         INIT_LIST_HEAD(&sparity->spages);
2880         sparity->dbitmap = sparity->bitmap;
2881         sparity->ebitmap = (void *)sparity->bitmap + bitmap_len;
2882
2883         ret = 0;
2884         while (logic_start < logic_end) {
2885                 if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
2886                         key.type = BTRFS_METADATA_ITEM_KEY;
2887                 else
2888                         key.type = BTRFS_EXTENT_ITEM_KEY;
2889                 key.objectid = logic_start;
2890                 key.offset = (u64)-1;
2891
2892                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2893                 if (ret < 0)
2894                         goto out;
2895
2896                 if (ret > 0) {
2897                         ret = btrfs_previous_extent_item(root, path, 0);
2898                         if (ret < 0)
2899                                 goto out;
2900                         if (ret > 0) {
2901                                 btrfs_release_path(path);
2902                                 ret = btrfs_search_slot(NULL, root, &key,
2903                                                         path, 0, 0);
2904                                 if (ret < 0)
2905                                         goto out;
2906                         }
2907                 }
2908
2909                 stop_loop = 0;
2910                 while (1) {
2911                         u64 bytes;
2912
2913                         l = path->nodes[0];
2914                         slot = path->slots[0];
2915                         if (slot >= btrfs_header_nritems(l)) {
2916                                 ret = btrfs_next_leaf(root, path);
2917                                 if (ret == 0)
2918                                         continue;
2919                                 if (ret < 0)
2920                                         goto out;
2921
2922                                 stop_loop = 1;
2923                                 break;
2924                         }
2925                         btrfs_item_key_to_cpu(l, &key, slot);
2926
2927                         if (key.type != BTRFS_EXTENT_ITEM_KEY &&
2928                             key.type != BTRFS_METADATA_ITEM_KEY)
2929                                 goto next;
2930
2931                         if (key.type == BTRFS_METADATA_ITEM_KEY)
2932                                 bytes = root->nodesize;
2933                         else
2934                                 bytes = key.offset;
2935
2936                         if (key.objectid + bytes <= logic_start)
2937                                 goto next;
2938
2939                         if (key.objectid >= logic_end) {
2940                                 stop_loop = 1;
2941                                 break;
2942                         }
2943
2944                         while (key.objectid >= logic_start + map->stripe_len)
2945                                 logic_start += map->stripe_len;
2946
2947                         extent = btrfs_item_ptr(l, slot,
2948                                                 struct btrfs_extent_item);
2949                         flags = btrfs_extent_flags(l, extent);
2950                         generation = btrfs_extent_generation(l, extent);
2951
2952                         if ((flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) &&
2953                             (key.objectid < logic_start ||
2954                              key.objectid + bytes >
2955                              logic_start + map->stripe_len)) {
2956                                 btrfs_err(fs_info, "scrub: tree block %llu spanning stripes, ignored. logical=%llu",
2957                                           key.objectid, logic_start);
2958                                 spin_lock(&sctx->stat_lock);
2959                                 sctx->stat.uncorrectable_errors++;
2960                                 spin_unlock(&sctx->stat_lock);
2961                                 goto next;
2962                         }
2963 again:
2964                         extent_logical = key.objectid;
2965                         extent_len = bytes;
2966
2967                         if (extent_logical < logic_start) {
2968                                 extent_len -= logic_start - extent_logical;
2969                                 extent_logical = logic_start;
2970                         }
2971
2972                         if (extent_logical + extent_len >
2973                             logic_start + map->stripe_len)
2974                                 extent_len = logic_start + map->stripe_len -
2975                                              extent_logical;
2976
2977                         scrub_parity_mark_sectors_data(sparity, extent_logical,
2978                                                        extent_len);
2979
2980                         mapped_length = extent_len;
2981                         ret = btrfs_map_block(fs_info, READ, extent_logical,
2982                                               &mapped_length, &bbio, 0);
2983                         if (!ret) {
2984                                 if (!bbio || mapped_length < extent_len)
2985                                         ret = -EIO;
2986                         }
2987                         if (ret) {
2988                                 btrfs_put_bbio(bbio);
2989                                 goto out;
2990                         }
2991                         extent_physical = bbio->stripes[0].physical;
2992                         extent_mirror_num = bbio->mirror_num;
2993                         extent_dev = bbio->stripes[0].dev;
2994                         btrfs_put_bbio(bbio);
2995
2996                         ret = btrfs_lookup_csums_range(csum_root,
2997                                                 extent_logical,
2998                                                 extent_logical + extent_len - 1,
2999                                                 &sctx->csum_list, 1);
3000                         if (ret)
3001                                 goto out;
3002
3003                         ret = scrub_extent_for_parity(sparity, extent_logical,
3004                                                       extent_len,
3005                                                       extent_physical,
3006                                                       extent_dev, flags,
3007                                                       generation,
3008                                                       extent_mirror_num);
3009
3010                         scrub_free_csums(sctx);
3011
3012                         if (ret)
3013                                 goto out;
3014
3015                         if (extent_logical + extent_len <
3016                             key.objectid + bytes) {
3017                                 logic_start += map->stripe_len;
3018
3019                                 if (logic_start >= logic_end) {
3020                                         stop_loop = 1;
3021                                         break;
3022                                 }
3023
3024                                 if (logic_start < key.objectid + bytes) {
3025                                         cond_resched();
3026                                         goto again;
3027                                 }
3028                         }
3029 next:
3030                         path->slots[0]++;
3031                 }
3032
3033                 btrfs_release_path(path);
3034
3035                 if (stop_loop)
3036                         break;
3037
3038                 logic_start += map->stripe_len;
3039         }
3040 out:
3041         if (ret < 0)
3042                 scrub_parity_mark_sectors_error(sparity, logic_start,
3043                                                 logic_end - logic_start);
3044         scrub_parity_put(sparity);
3045         scrub_submit(sctx);
3046         mutex_lock(&sctx->wr_ctx.wr_lock);
3047         scrub_wr_submit(sctx);
3048         mutex_unlock(&sctx->wr_ctx.wr_lock);
3049
3050         btrfs_release_path(path);
3051         return ret < 0 ? ret : 0;
3052 }
3053
3054 static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
3055                                            struct map_lookup *map,
3056                                            struct btrfs_device *scrub_dev,
3057                                            int num, u64 base, u64 length,
3058                                            int is_dev_replace)
3059 {
3060         struct btrfs_path *path, *ppath;
3061         struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;
3062         struct btrfs_root *root = fs_info->extent_root;
3063         struct btrfs_root *csum_root = fs_info->csum_root;
3064         struct btrfs_extent_item *extent;
3065         struct blk_plug plug;
3066         u64 flags;
3067         int ret;
3068         int slot;
3069         u64 nstripes;
3070         struct extent_buffer *l;
3071         struct btrfs_key key;
3072         u64 physical;
3073         u64 logical;
3074         u64 logic_end;
3075         u64 physical_end;
3076         u64 generation;
3077         int mirror_num;
3078         struct reada_control *reada1;
3079         struct reada_control *reada2;
3080         struct btrfs_key key_start;
3081         struct btrfs_key key_end;
3082         u64 increment = map->stripe_len;
3083         u64 offset;
3084         u64 extent_logical;
3085         u64 extent_physical;
3086         u64 extent_len;
3087         u64 stripe_logical;
3088         u64 stripe_end;
3089         struct btrfs_device *extent_dev;
3090         int extent_mirror_num;
3091         int stop_loop = 0;
3092
3093         physical = map->stripes[num].physical;
3094         offset = 0;
3095         nstripes = div_u64(length, map->stripe_len);
3096         if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
3097                 offset = map->stripe_len * num;
3098                 increment = map->stripe_len * map->num_stripes;
3099                 mirror_num = 1;
3100         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
3101                 int factor = map->num_stripes / map->sub_stripes;
3102                 offset = map->stripe_len * (num / map->sub_stripes);
3103                 increment = map->stripe_len * factor;
3104                 mirror_num = num % map->sub_stripes + 1;
3105         } else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
3106                 increment = map->stripe_len;
3107                 mirror_num = num % map->num_stripes + 1;
3108         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
3109                 increment = map->stripe_len;
3110                 mirror_num = num % map->num_stripes + 1;
3111         } else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
3112                 get_raid56_logic_offset(physical, num, map, &offset, NULL);
3113                 increment = map->stripe_len * nr_data_stripes(map);
3114                 mirror_num = 1;
3115         } else {
3116                 increment = map->stripe_len;
3117                 mirror_num = 1;
3118         }
3119
3120         path = btrfs_alloc_path();
3121         if (!path)
3122                 return -ENOMEM;
3123
3124         ppath = btrfs_alloc_path();
3125         if (!ppath) {
3126                 btrfs_free_path(path);
3127                 return -ENOMEM;
3128         }
3129
3130         /*
3131          * work on commit root. The related disk blocks are static as
3132          * long as COW is applied. This means, it is save to rewrite
3133          * them to repair disk errors without any race conditions
3134          */
3135         path->search_commit_root = 1;
3136         path->skip_locking = 1;
3137
3138         ppath->search_commit_root = 1;
3139         ppath->skip_locking = 1;
3140         /*
3141          * trigger the readahead for extent tree csum tree and wait for
3142          * completion. During readahead, the scrub is officially paused
3143          * to not hold off transaction commits
3144          */
3145         logical = base + offset;
3146         physical_end = physical + nstripes * map->stripe_len;
3147         if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
3148                 get_raid56_logic_offset(physical_end, num,
3149                                         map, &logic_end, NULL);
3150                 logic_end += base;
3151         } else {
3152                 logic_end = logical + increment * nstripes;
3153         }
3154         wait_event(sctx->list_wait,
3155                    atomic_read(&sctx->bios_in_flight) == 0);
3156         scrub_blocked_if_needed(fs_info);
3157
3158         /* FIXME it might be better to start readahead at commit root */
3159         key_start.objectid = logical;
3160         key_start.type = BTRFS_EXTENT_ITEM_KEY;
3161         key_start.offset = (u64)0;
3162         key_end.objectid = logic_end;
3163         key_end.type = BTRFS_METADATA_ITEM_KEY;
3164         key_end.offset = (u64)-1;
3165         reada1 = btrfs_reada_add(root, &key_start, &key_end);
3166
3167         key_start.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
3168         key_start.type = BTRFS_EXTENT_CSUM_KEY;
3169         key_start.offset = logical;
3170         key_end.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
3171         key_end.type = BTRFS_EXTENT_CSUM_KEY;
3172         key_end.offset = logic_end;
3173         reada2 = btrfs_reada_add(csum_root, &key_start, &key_end);
3174
3175         if (!IS_ERR(reada1))
3176                 btrfs_reada_wait(reada1);
3177         if (!IS_ERR(reada2))
3178                 btrfs_reada_wait(reada2);
3179
3180
3181         /*
3182          * collect all data csums for the stripe to avoid seeking during
3183          * the scrub. This might currently (crc32) end up to be about 1MB
3184          */
3185         blk_start_plug(&plug);
3186
3187         /*
3188          * now find all extents for each stripe and scrub them
3189          */
3190         ret = 0;
3191         while (physical < physical_end) {
3192                 /*
3193                  * canceled?
3194                  */
3195                 if (atomic_read(&fs_info->scrub_cancel_req) ||
3196                     atomic_read(&sctx->cancel_req)) {
3197                         ret = -ECANCELED;
3198                         goto out;
3199                 }
3200                 /*
3201                  * check to see if we have to pause
3202                  */
3203                 if (atomic_read(&fs_info->scrub_pause_req)) {
3204                         /* push queued extents */
3205                         atomic_set(&sctx->wr_ctx.flush_all_writes, 1);
3206                         scrub_submit(sctx);
3207                         mutex_lock(&sctx->wr_ctx.wr_lock);
3208                         scrub_wr_submit(sctx);
3209                         mutex_unlock(&sctx->wr_ctx.wr_lock);
3210                         wait_event(sctx->list_wait,
3211                                    atomic_read(&sctx->bios_in_flight) == 0);
3212                         atomic_set(&sctx->wr_ctx.flush_all_writes, 0);
3213                         scrub_blocked_if_needed(fs_info);
3214                 }
3215
3216                 if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
3217                         ret = get_raid56_logic_offset(physical, num, map,
3218                                                       &logical,
3219                                                       &stripe_logical);
3220                         logical += base;
3221                         if (ret) {
3222                                 /* it is parity strip */
3223                                 stripe_logical += base;
3224                                 stripe_end = stripe_logical + increment;
3225                                 ret = scrub_raid56_parity(sctx, map, scrub_dev,
3226                                                           ppath, stripe_logical,
3227                                                           stripe_end);
3228                                 if (ret)
3229                                         goto out;
3230                                 goto skip;
3231                         }
3232                 }
3233
3234                 if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
3235                         key.type = BTRFS_METADATA_ITEM_KEY;
3236                 else
3237                         key.type = BTRFS_EXTENT_ITEM_KEY;
3238                 key.objectid = logical;
3239                 key.offset = (u64)-1;
3240
3241                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3242                 if (ret < 0)
3243                         goto out;
3244
3245                 if (ret > 0) {
3246                         ret = btrfs_previous_extent_item(root, path, 0);
3247                         if (ret < 0)
3248                                 goto out;
3249                         if (ret > 0) {
3250                                 /* there's no smaller item, so stick with the
3251                                  * larger one */
3252                                 btrfs_release_path(path);
3253                                 ret = btrfs_search_slot(NULL, root, &key,
3254                                                         path, 0, 0);
3255                                 if (ret < 0)
3256                                         goto out;
3257                         }
3258                 }
3259
3260                 stop_loop = 0;
3261                 while (1) {
3262                         u64 bytes;
3263
3264                         l = path->nodes[0];
3265                         slot = path->slots[0];
3266                         if (slot >= btrfs_header_nritems(l)) {
3267                                 ret = btrfs_next_leaf(root, path);
3268                                 if (ret == 0)
3269                                         continue;
3270                                 if (ret < 0)
3271                                         goto out;
3272
3273                                 stop_loop = 1;
3274                                 break;
3275                         }
3276                         btrfs_item_key_to_cpu(l, &key, slot);
3277
3278                         if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3279                             key.type != BTRFS_METADATA_ITEM_KEY)
3280                                 goto next;
3281
3282                         if (key.type == BTRFS_METADATA_ITEM_KEY)
3283                                 bytes = root->nodesize;
3284                         else
3285                                 bytes = key.offset;
3286
3287                         if (key.objectid + bytes <= logical)
3288                                 goto next;
3289
3290                         if (key.objectid >= logical + map->stripe_len) {
3291                                 /* out of this device extent */
3292                                 if (key.objectid >= logic_end)
3293                                         stop_loop = 1;
3294                                 break;
3295                         }
3296
3297                         extent = btrfs_item_ptr(l, slot,
3298                                                 struct btrfs_extent_item);
3299                         flags = btrfs_extent_flags(l, extent);
3300                         generation = btrfs_extent_generation(l, extent);
3301
3302                         if ((flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) &&
3303                             (key.objectid < logical ||
3304                              key.objectid + bytes >
3305                              logical + map->stripe_len)) {
3306                                 btrfs_err(fs_info,
3307                                            "scrub: tree block %llu spanning "
3308                                            "stripes, ignored. logical=%llu",
3309                                        key.objectid, logical);
3310                                 spin_lock(&sctx->stat_lock);
3311                                 sctx->stat.uncorrectable_errors++;
3312                                 spin_unlock(&sctx->stat_lock);
3313                                 goto next;
3314                         }
3315
3316 again:
3317                         extent_logical = key.objectid;
3318                         extent_len = bytes;
3319
3320                         /*
3321                          * trim extent to this stripe
3322                          */
3323                         if (extent_logical < logical) {
3324                                 extent_len -= logical - extent_logical;
3325                                 extent_logical = logical;
3326                         }
3327                         if (extent_logical + extent_len >
3328                             logical + map->stripe_len) {
3329                                 extent_len = logical + map->stripe_len -
3330                                              extent_logical;
3331                         }
3332
3333                         extent_physical = extent_logical - logical + physical;
3334                         extent_dev = scrub_dev;
3335                         extent_mirror_num = mirror_num;
3336                         if (is_dev_replace)
3337                                 scrub_remap_extent(fs_info, extent_logical,
3338                                                    extent_len, &extent_physical,
3339                                                    &extent_dev,
3340                                                    &extent_mirror_num);
3341
3342                         ret = btrfs_lookup_csums_range(csum_root,
3343                                                        extent_logical,
3344                                                        extent_logical +
3345                                                        extent_len - 1,
3346                                                        &sctx->csum_list, 1);
3347                         if (ret)
3348                                 goto out;
3349
3350                         ret = scrub_extent(sctx, extent_logical, extent_len,
3351                                            extent_physical, extent_dev, flags,
3352                                            generation, extent_mirror_num,
3353                                            extent_logical - logical + physical);
3354
3355                         scrub_free_csums(sctx);
3356
3357                         if (ret)
3358                                 goto out;
3359
3360                         if (extent_logical + extent_len <
3361                             key.objectid + bytes) {
3362                                 if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
3363                                         /*
3364                                          * loop until we find next data stripe
3365                                          * or we have finished all stripes.
3366                                          */
3367 loop:
3368                                         physical += map->stripe_len;
3369                                         ret = get_raid56_logic_offset(physical,
3370                                                         num, map, &logical,
3371                                                         &stripe_logical);
3372                                         logical += base;
3373
3374                                         if (ret && physical < physical_end) {
3375                                                 stripe_logical += base;
3376                                                 stripe_end = stripe_logical +
3377                                                                 increment;
3378                                                 ret = scrub_raid56_parity(sctx,
3379                                                         map, scrub_dev, ppath,
3380                                                         stripe_logical,
3381                                                         stripe_end);
3382                                                 if (ret)
3383                                                         goto out;
3384                                                 goto loop;
3385                                         }
3386                                 } else {
3387                                         physical += map->stripe_len;
3388                                         logical += increment;
3389                                 }
3390                                 if (logical < key.objectid + bytes) {
3391                                         cond_resched();
3392                                         goto again;
3393                                 }
3394
3395                                 if (physical >= physical_end) {
3396                                         stop_loop = 1;
3397                                         break;
3398                                 }
3399                         }
3400 next:
3401                         path->slots[0]++;
3402                 }
3403                 btrfs_release_path(path);
3404 skip:
3405                 logical += increment;
3406                 physical += map->stripe_len;
3407                 spin_lock(&sctx->stat_lock);
3408                 if (stop_loop)
3409                         sctx->stat.last_physical = map->stripes[num].physical +
3410                                                    length;
3411                 else
3412                         sctx->stat.last_physical = physical;
3413                 spin_unlock(&sctx->stat_lock);
3414                 if (stop_loop)
3415                         break;
3416         }
3417 out:
3418         /* push queued extents */
3419         scrub_submit(sctx);
3420         mutex_lock(&sctx->wr_ctx.wr_lock);
3421         scrub_wr_submit(sctx);
3422         mutex_unlock(&sctx->wr_ctx.wr_lock);
3423
3424         blk_finish_plug(&plug);
3425         btrfs_free_path(path);
3426         btrfs_free_path(ppath);
3427         return ret < 0 ? ret : 0;
3428 }
3429
3430 static noinline_for_stack int scrub_chunk(struct scrub_ctx *sctx,
3431                                           struct btrfs_device *scrub_dev,
3432                                           u64 chunk_offset, u64 length,
3433                                           u64 dev_offset,
3434                                           struct btrfs_block_group_cache *cache,
3435                                           int is_dev_replace)
3436 {
3437         struct btrfs_mapping_tree *map_tree =
3438                 &sctx->dev_root->fs_info->mapping_tree;
3439         struct map_lookup *map;
3440         struct extent_map *em;
3441         int i;
3442         int ret = 0;
3443
3444         read_lock(&map_tree->map_tree.lock);
3445         em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
3446         read_unlock(&map_tree->map_tree.lock);
3447
3448         if (!em) {
3449                 /*
3450                  * Might have been an unused block group deleted by the cleaner
3451                  * kthread or relocation.
3452                  */
3453                 spin_lock(&cache->lock);
3454                 if (!cache->removed)
3455                         ret = -EINVAL;
3456                 spin_unlock(&cache->lock);
3457
3458                 return ret;
3459         }
3460
3461         map = em->map_lookup;
3462         if (em->start != chunk_offset)
3463                 goto out;
3464
3465         if (em->len < length)
3466                 goto out;
3467
3468         for (i = 0; i < map->num_stripes; ++i) {
3469                 if (map->stripes[i].dev->bdev == scrub_dev->bdev &&
3470                     map->stripes[i].physical == dev_offset) {
3471                         ret = scrub_stripe(sctx, map, scrub_dev, i,
3472                                            chunk_offset, length,
3473                                            is_dev_replace);
3474                         if (ret)
3475                                 goto out;
3476                 }
3477         }
3478 out:
3479         free_extent_map(em);
3480
3481         return ret;
3482 }
3483
3484 static noinline_for_stack
3485 int scrub_enumerate_chunks(struct scrub_ctx *sctx,
3486                            struct btrfs_device *scrub_dev, u64 start, u64 end,
3487                            int is_dev_replace)
3488 {
3489         struct btrfs_dev_extent *dev_extent = NULL;
3490         struct btrfs_path *path;
3491         struct btrfs_root *root = sctx->dev_root;
3492         struct btrfs_fs_info *fs_info = root->fs_info;
3493         u64 length;
3494         u64 chunk_offset;
3495         int ret = 0;
3496         int ro_set;
3497         int slot;
3498         struct extent_buffer *l;
3499         struct btrfs_key key;
3500         struct btrfs_key found_key;
3501         struct btrfs_block_group_cache *cache;
3502         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
3503
3504         path = btrfs_alloc_path();
3505         if (!path)
3506                 return -ENOMEM;
3507
3508         path->reada = READA_FORWARD;
3509         path->search_commit_root = 1;
3510         path->skip_locking = 1;
3511
3512         key.objectid = scrub_dev->devid;
3513         key.offset = 0ull;
3514         key.type = BTRFS_DEV_EXTENT_KEY;
3515
3516         while (1) {
3517                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3518                 if (ret < 0)
3519                         break;
3520                 if (ret > 0) {
3521                         if (path->slots[0] >=
3522                             btrfs_header_nritems(path->nodes[0])) {
3523                                 ret = btrfs_next_leaf(root, path);
3524                                 if (ret < 0)
3525                                         break;
3526                                 if (ret > 0) {
3527                                         ret = 0;
3528                                         break;
3529                                 }
3530                         } else {
3531                                 ret = 0;
3532                         }
3533                 }
3534
3535                 l = path->nodes[0];
3536                 slot = path->slots[0];
3537
3538                 btrfs_item_key_to_cpu(l, &found_key, slot);
3539
3540                 if (found_key.objectid != scrub_dev->devid)
3541                         break;
3542
3543                 if (found_key.type != BTRFS_DEV_EXTENT_KEY)
3544                         break;
3545
3546                 if (found_key.offset >= end)
3547                         break;
3548
3549                 if (found_key.offset < key.offset)
3550                         break;
3551
3552                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
3553                 length = btrfs_dev_extent_length(l, dev_extent);
3554
3555                 if (found_key.offset + length <= start)
3556                         goto skip;
3557
3558                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
3559
3560                 /*
3561                  * get a reference on the corresponding block group to prevent
3562                  * the chunk from going away while we scrub it
3563                  */
3564                 cache = btrfs_lookup_block_group(fs_info, chunk_offset);
3565
3566                 /* some chunks are removed but not committed to disk yet,
3567                  * continue scrubbing */
3568                 if (!cache)
3569                         goto skip;
3570
3571                 /*
3572                  * we need call btrfs_inc_block_group_ro() with scrubs_paused,
3573                  * to avoid deadlock caused by:
3574                  * btrfs_inc_block_group_ro()
3575                  * -> btrfs_wait_for_commit()
3576                  * -> btrfs_commit_transaction()
3577                  * -> btrfs_scrub_pause()
3578                  */
3579                 scrub_pause_on(fs_info);
3580                 ret = btrfs_inc_block_group_ro(root, cache);
3581                 scrub_pause_off(fs_info);
3582
3583                 if (ret == 0) {
3584                         ro_set = 1;
3585                 } else if (ret == -ENOSPC) {
3586                         /*
3587                          * btrfs_inc_block_group_ro return -ENOSPC when it
3588                          * failed in creating new chunk for metadata.
3589                          * It is not a problem for scrub/replace, because
3590                          * metadata are always cowed, and our scrub paused
3591                          * commit_transactions.
3592                          */
3593                         ro_set = 0;
3594                 } else {
3595                         btrfs_warn(fs_info, "failed setting block group ro, ret=%d\n",
3596                                    ret);
3597                         btrfs_put_block_group(cache);
3598                         break;
3599                 }
3600
3601                 dev_replace->cursor_right = found_key.offset + length;
3602                 dev_replace->cursor_left = found_key.offset;
3603                 dev_replace->item_needs_writeback = 1;
3604                 ret = scrub_chunk(sctx, scrub_dev, chunk_offset, length,
3605                                   found_key.offset, cache, is_dev_replace);
3606
3607                 /*
3608                  * flush, submit all pending read and write bios, afterwards
3609                  * wait for them.
3610                  * Note that in the dev replace case, a read request causes
3611                  * write requests that are submitted in the read completion
3612                  * worker. Therefore in the current situation, it is required
3613                  * that all write requests are flushed, so that all read and
3614                  * write requests are really completed when bios_in_flight
3615                  * changes to 0.
3616                  */
3617                 atomic_set(&sctx->wr_ctx.flush_all_writes, 1);
3618                 scrub_submit(sctx);
3619                 mutex_lock(&sctx->wr_ctx.wr_lock);
3620                 scrub_wr_submit(sctx);
3621                 mutex_unlock(&sctx->wr_ctx.wr_lock);
3622
3623                 wait_event(sctx->list_wait,
3624                            atomic_read(&sctx->bios_in_flight) == 0);
3625
3626                 scrub_pause_on(fs_info);
3627
3628                 /*
3629                  * must be called before we decrease @scrub_paused.
3630                  * make sure we don't block transaction commit while
3631                  * we are waiting pending workers finished.
3632                  */
3633                 wait_event(sctx->list_wait,
3634                            atomic_read(&sctx->workers_pending) == 0);
3635                 atomic_set(&sctx->wr_ctx.flush_all_writes, 0);
3636
3637                 scrub_pause_off(fs_info);
3638
3639                 if (ro_set)
3640                         btrfs_dec_block_group_ro(root, cache);
3641
3642                 /*
3643                  * We might have prevented the cleaner kthread from deleting
3644                  * this block group if it was already unused because we raced
3645                  * and set it to RO mode first. So add it back to the unused
3646                  * list, otherwise it might not ever be deleted unless a manual
3647                  * balance is triggered or it becomes used and unused again.
3648                  */
3649                 spin_lock(&cache->lock);
3650                 if (!cache->removed && !cache->ro && cache->reserved == 0 &&
3651                     btrfs_block_group_used(&cache->item) == 0) {
3652                         spin_unlock(&cache->lock);
3653                         spin_lock(&fs_info->unused_bgs_lock);
3654                         if (list_empty(&cache->bg_list)) {
3655                                 btrfs_get_block_group(cache);
3656                                 list_add_tail(&cache->bg_list,
3657                                               &fs_info->unused_bgs);
3658                         }
3659                         spin_unlock(&fs_info->unused_bgs_lock);
3660                 } else {
3661                         spin_unlock(&cache->lock);
3662                 }
3663
3664                 btrfs_put_block_group(cache);
3665                 if (ret)
3666                         break;
3667                 if (is_dev_replace &&
3668                     atomic64_read(&dev_replace->num_write_errors) > 0) {
3669                         ret = -EIO;
3670                         break;
3671                 }
3672                 if (sctx->stat.malloc_errors > 0) {
3673                         ret = -ENOMEM;
3674                         break;
3675                 }
3676
3677                 dev_replace->cursor_left = dev_replace->cursor_right;
3678                 dev_replace->item_needs_writeback = 1;
3679 skip:
3680                 key.offset = found_key.offset + length;
3681                 btrfs_release_path(path);
3682         }
3683
3684         btrfs_free_path(path);
3685
3686         return ret;
3687 }
3688
3689 static noinline_for_stack int scrub_supers(struct scrub_ctx *sctx,
3690                                            struct btrfs_device *scrub_dev)
3691 {
3692         int     i;
3693         u64     bytenr;
3694         u64     gen;
3695         int     ret;
3696         struct btrfs_root *root = sctx->dev_root;
3697
3698         if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
3699                 return -EIO;
3700
3701         /* Seed devices of a new filesystem has their own generation. */
3702         if (scrub_dev->fs_devices != root->fs_info->fs_devices)
3703                 gen = scrub_dev->generation;
3704         else
3705                 gen = root->fs_info->last_trans_committed;
3706
3707         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
3708                 bytenr = btrfs_sb_offset(i);
3709                 if (bytenr + BTRFS_SUPER_INFO_SIZE >
3710                     scrub_dev->commit_total_bytes)
3711                         break;
3712
3713                 ret = scrub_pages(sctx, bytenr, BTRFS_SUPER_INFO_SIZE, bytenr,
3714                                   scrub_dev, BTRFS_EXTENT_FLAG_SUPER, gen, i,
3715                                   NULL, 1, bytenr);
3716                 if (ret)
3717                         return ret;
3718         }
3719         wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0);
3720
3721         return 0;
3722 }
3723
3724 /*
3725  * get a reference count on fs_info->scrub_workers. start worker if necessary
3726  */
3727 static noinline_for_stack int scrub_workers_get(struct btrfs_fs_info *fs_info,
3728                                                 int is_dev_replace)
3729 {
3730         unsigned int flags = WQ_FREEZABLE | WQ_UNBOUND;
3731         int max_active = fs_info->thread_pool_size;
3732
3733         if (fs_info->scrub_workers_refcnt == 0) {
3734                 if (is_dev_replace)
3735                         fs_info->scrub_workers =
3736                                 btrfs_alloc_workqueue("scrub", flags,
3737                                                       1, 4);
3738                 else
3739                         fs_info->scrub_workers =
3740                                 btrfs_alloc_workqueue("scrub", flags,
3741                                                       max_active, 4);
3742                 if (!fs_info->scrub_workers)
3743                         goto fail_scrub_workers;
3744
3745                 fs_info->scrub_wr_completion_workers =
3746                         btrfs_alloc_workqueue("scrubwrc", flags,
3747                                               max_active, 2);
3748                 if (!fs_info->scrub_wr_completion_workers)
3749                         goto fail_scrub_wr_completion_workers;
3750
3751                 fs_info->scrub_nocow_workers =
3752                         btrfs_alloc_workqueue("scrubnc", flags, 1, 0);
3753                 if (!fs_info->scrub_nocow_workers)
3754                         goto fail_scrub_nocow_workers;
3755                 fs_info->scrub_parity_workers =
3756                         btrfs_alloc_workqueue("scrubparity", flags,
3757                                               max_active, 2);
3758                 if (!fs_info->scrub_parity_workers)
3759                         goto fail_scrub_parity_workers;
3760         }
3761         ++fs_info->scrub_workers_refcnt;
3762         return 0;
3763
3764 fail_scrub_parity_workers:
3765         btrfs_destroy_workqueue(fs_info->scrub_nocow_workers);
3766 fail_scrub_nocow_workers:
3767         btrfs_destroy_workqueue(fs_info->scrub_wr_completion_workers);
3768 fail_scrub_wr_completion_workers:
3769         btrfs_destroy_workqueue(fs_info->scrub_workers);
3770 fail_scrub_workers:
3771         return -ENOMEM;
3772 }
3773
3774 static noinline_for_stack void scrub_workers_put(struct btrfs_fs_info *fs_info)
3775 {
3776         if (--fs_info->scrub_workers_refcnt == 0) {
3777                 btrfs_destroy_workqueue(fs_info->scrub_workers);
3778                 btrfs_destroy_workqueue(fs_info->scrub_wr_completion_workers);
3779                 btrfs_destroy_workqueue(fs_info->scrub_nocow_workers);
3780                 btrfs_destroy_workqueue(fs_info->scrub_parity_workers);
3781         }
3782         WARN_ON(fs_info->scrub_workers_refcnt < 0);
3783 }
3784
3785 int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
3786                     u64 end, struct btrfs_scrub_progress *progress,
3787                     int readonly, int is_dev_replace)
3788 {
3789         struct scrub_ctx *sctx;
3790         int ret;
3791         struct btrfs_device *dev;
3792         struct rcu_string *name;
3793
3794         if (btrfs_fs_closing(fs_info))
3795                 return -EINVAL;
3796
3797         if (fs_info->chunk_root->nodesize > BTRFS_STRIPE_LEN) {
3798                 /*
3799                  * in this case scrub is unable to calculate the checksum
3800                  * the way scrub is implemented. Do not handle this
3801                  * situation at all because it won't ever happen.
3802                  */
3803                 btrfs_err(fs_info,
3804                            "scrub: size assumption nodesize <= BTRFS_STRIPE_LEN (%d <= %d) fails",
3805                        fs_info->chunk_root->nodesize, BTRFS_STRIPE_LEN);
3806                 return -EINVAL;
3807         }
3808
3809         if (fs_info->chunk_root->sectorsize != PAGE_SIZE) {
3810                 /* not supported for data w/o checksums */
3811                 btrfs_err(fs_info,
3812                            "scrub: size assumption sectorsize != PAGE_SIZE "
3813                            "(%d != %lu) fails",
3814                        fs_info->chunk_root->sectorsize, PAGE_SIZE);
3815                 return -EINVAL;
3816         }
3817
3818         if (fs_info->chunk_root->nodesize >
3819             PAGE_SIZE * SCRUB_MAX_PAGES_PER_BLOCK ||
3820             fs_info->chunk_root->sectorsize >
3821             PAGE_SIZE * SCRUB_MAX_PAGES_PER_BLOCK) {
3822                 /*
3823                  * would exhaust the array bounds of pagev member in
3824                  * struct scrub_block
3825                  */
3826                 btrfs_err(fs_info, "scrub: size assumption nodesize and sectorsize "
3827                            "<= SCRUB_MAX_PAGES_PER_BLOCK (%d <= %d && %d <= %d) fails",
3828                        fs_info->chunk_root->nodesize,
3829                        SCRUB_MAX_PAGES_PER_BLOCK,
3830                        fs_info->chunk_root->sectorsize,
3831                        SCRUB_MAX_PAGES_PER_BLOCK);
3832                 return -EINVAL;
3833         }
3834
3835
3836         mutex_lock(&fs_info->fs_devices->device_list_mutex);
3837         dev = btrfs_find_device(fs_info, devid, NULL, NULL);
3838         if (!dev || (dev->missing && !is_dev_replace)) {
3839                 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3840                 return -ENODEV;
3841         }
3842
3843         if (!is_dev_replace && !readonly && !dev->writeable) {
3844                 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3845                 rcu_read_lock();
3846                 name = rcu_dereference(dev->name);
3847                 btrfs_err(fs_info, "scrub: device %s is not writable",
3848                           name->str);
3849                 rcu_read_unlock();
3850                 return -EROFS;
3851         }
3852
3853         mutex_lock(&fs_info->scrub_lock);
3854         if (!dev->in_fs_metadata || dev->is_tgtdev_for_dev_replace) {
3855                 mutex_unlock(&fs_info->scrub_lock);
3856                 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3857                 return -EIO;
3858         }
3859
3860         btrfs_dev_replace_lock(&fs_info->dev_replace);
3861         if (dev->scrub_device ||
3862             (!is_dev_replace &&
3863              btrfs_dev_replace_is_ongoing(&fs_info->dev_replace))) {
3864                 btrfs_dev_replace_unlock(&fs_info->dev_replace);
3865                 mutex_unlock(&fs_info->scrub_lock);
3866                 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3867                 return -EINPROGRESS;
3868         }
3869         btrfs_dev_replace_unlock(&fs_info->dev_replace);
3870
3871         ret = scrub_workers_get(fs_info, is_dev_replace);
3872         if (ret) {
3873                 mutex_unlock(&fs_info->scrub_lock);
3874                 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3875                 return ret;
3876         }
3877
3878         sctx = scrub_setup_ctx(dev, is_dev_replace);
3879         if (IS_ERR(sctx)) {
3880                 mutex_unlock(&fs_info->scrub_lock);
3881                 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3882                 scrub_workers_put(fs_info);
3883                 return PTR_ERR(sctx);
3884         }
3885         sctx->readonly = readonly;
3886         dev->scrub_device = sctx;
3887         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3888
3889         /*
3890          * checking @scrub_pause_req here, we can avoid
3891          * race between committing transaction and scrubbing.
3892          */
3893         __scrub_blocked_if_needed(fs_info);
3894         atomic_inc(&fs_info->scrubs_running);
3895         mutex_unlock(&fs_info->scrub_lock);
3896
3897         if (!is_dev_replace) {
3898                 /*
3899                  * by holding device list mutex, we can
3900                  * kick off writing super in log tree sync.
3901                  */
3902                 mutex_lock(&fs_info->fs_devices->device_list_mutex);
3903                 ret = scrub_supers(sctx, dev);
3904                 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3905         }
3906
3907         if (!ret)
3908                 ret = scrub_enumerate_chunks(sctx, dev, start, end,
3909                                              is_dev_replace);
3910
3911         wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0);
3912         atomic_dec(&fs_info->scrubs_running);
3913         wake_up(&fs_info->scrub_pause_wait);
3914
3915         wait_event(sctx->list_wait, atomic_read(&sctx->workers_pending) == 0);
3916
3917         if (progress)
3918                 memcpy(progress, &sctx->stat, sizeof(*progress));
3919
3920         mutex_lock(&fs_info->scrub_lock);
3921         dev->scrub_device = NULL;
3922         scrub_workers_put(fs_info);
3923         mutex_unlock(&fs_info->scrub_lock);
3924
3925         scrub_put_ctx(sctx);
3926
3927         return ret;
3928 }
3929
3930 void btrfs_scrub_pause(struct btrfs_root *root)
3931 {
3932         struct btrfs_fs_info *fs_info = root->fs_info;
3933
3934         mutex_lock(&fs_info->scrub_lock);
3935         atomic_inc(&fs_info->scrub_pause_req);
3936         while (atomic_read(&fs_info->scrubs_paused) !=
3937                atomic_read(&fs_info->scrubs_running)) {
3938                 mutex_unlock(&fs_info->scrub_lock);
3939                 wait_event(fs_info->scrub_pause_wait,
3940                            atomic_read(&fs_info->scrubs_paused) ==
3941                            atomic_read(&fs_info->scrubs_running));
3942                 mutex_lock(&fs_info->scrub_lock);
3943         }
3944         mutex_unlock(&fs_info->scrub_lock);
3945 }
3946
3947 void btrfs_scrub_continue(struct btrfs_root *root)
3948 {
3949         struct btrfs_fs_info *fs_info = root->fs_info;
3950
3951         atomic_dec(&fs_info->scrub_pause_req);
3952         wake_up(&fs_info->scrub_pause_wait);
3953 }
3954
3955 int btrfs_scrub_cancel(struct btrfs_fs_info *fs_info)
3956 {
3957         mutex_lock(&fs_info->scrub_lock);
3958         if (!atomic_read(&fs_info->scrubs_running)) {
3959                 mutex_unlock(&fs_info->scrub_lock);
3960                 return -ENOTCONN;
3961         }
3962
3963         atomic_inc(&fs_info->scrub_cancel_req);
3964         while (atomic_read(&fs_info->scrubs_running)) {
3965                 mutex_unlock(&fs_info->scrub_lock);
3966                 wait_event(fs_info->scrub_pause_wait,
3967                            atomic_read(&fs_info->scrubs_running) == 0);
3968                 mutex_lock(&fs_info->scrub_lock);
3969         }
3970         atomic_dec(&fs_info->scrub_cancel_req);
3971         mutex_unlock(&fs_info->scrub_lock);
3972
3973         return 0;
3974 }
3975
3976 int btrfs_scrub_cancel_dev(struct btrfs_fs_info *fs_info,
3977                            struct btrfs_device *dev)
3978 {
3979         struct scrub_ctx *sctx;
3980
3981         mutex_lock(&fs_info->scrub_lock);
3982         sctx = dev->scrub_device;
3983         if (!sctx) {
3984                 mutex_unlock(&fs_info->scrub_lock);
3985                 return -ENOTCONN;
3986         }
3987         atomic_inc(&sctx->cancel_req);
3988         while (dev->scrub_device) {
3989                 mutex_unlock(&fs_info->scrub_lock);
3990                 wait_event(fs_info->scrub_pause_wait,
3991                            dev->scrub_device == NULL);
3992                 mutex_lock(&fs_info->scrub_lock);
3993         }
3994         mutex_unlock(&fs_info->scrub_lock);
3995
3996         return 0;
3997 }
3998
3999 int btrfs_scrub_progress(struct btrfs_root *root, u64 devid,
4000                          struct btrfs_scrub_progress *progress)
4001 {
4002         struct btrfs_device *dev;
4003         struct scrub_ctx *sctx = NULL;
4004
4005         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
4006         dev = btrfs_find_device(root->fs_info, devid, NULL, NULL);
4007         if (dev)
4008                 sctx = dev->scrub_device;
4009         if (sctx)
4010                 memcpy(progress, &sctx->stat, sizeof(*progress));
4011         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
4012
4013         return dev ? (sctx ? 0 : -ENOTCONN) : -ENODEV;
4014 }
4015
4016 static void scrub_remap_extent(struct btrfs_fs_info *fs_info,
4017                                u64 extent_logical, u64 extent_len,
4018                                u64 *extent_physical,
4019                                struct btrfs_device **extent_dev,
4020                                int *extent_mirror_num)
4021 {
4022         u64 mapped_length;
4023         struct btrfs_bio *bbio = NULL;
4024         int ret;
4025
4026         mapped_length = extent_len;
4027         ret = btrfs_map_block(fs_info, READ, extent_logical,
4028                               &mapped_length, &bbio, 0);
4029         if (ret || !bbio || mapped_length < extent_len ||
4030             !bbio->stripes[0].dev->bdev) {
4031                 btrfs_put_bbio(bbio);
4032                 return;
4033         }
4034
4035         *extent_physical = bbio->stripes[0].physical;
4036         *extent_mirror_num = bbio->mirror_num;
4037         *extent_dev = bbio->stripes[0].dev;
4038         btrfs_put_bbio(bbio);
4039 }
4040
4041 static int scrub_setup_wr_ctx(struct scrub_ctx *sctx,
4042                               struct scrub_wr_ctx *wr_ctx,
4043                               struct btrfs_fs_info *fs_info,
4044                               struct btrfs_device *dev,
4045                               int is_dev_replace)
4046 {
4047         WARN_ON(wr_ctx->wr_curr_bio != NULL);
4048
4049         mutex_init(&wr_ctx->wr_lock);
4050         wr_ctx->wr_curr_bio = NULL;
4051         if (!is_dev_replace)
4052                 return 0;
4053
4054         WARN_ON(!dev->bdev);
4055         wr_ctx->pages_per_wr_bio = SCRUB_PAGES_PER_WR_BIO;
4056         wr_ctx->tgtdev = dev;
4057         atomic_set(&wr_ctx->flush_all_writes, 0);
4058         return 0;
4059 }
4060
4061 static void scrub_free_wr_ctx(struct scrub_wr_ctx *wr_ctx)
4062 {
4063         mutex_lock(&wr_ctx->wr_lock);
4064         kfree(wr_ctx->wr_curr_bio);
4065         wr_ctx->wr_curr_bio = NULL;
4066         mutex_unlock(&wr_ctx->wr_lock);
4067 }
4068
4069 static int copy_nocow_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
4070                             int mirror_num, u64 physical_for_dev_replace)
4071 {
4072         struct scrub_copy_nocow_ctx *nocow_ctx;
4073         struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;
4074
4075         nocow_ctx = kzalloc(sizeof(*nocow_ctx), GFP_NOFS);
4076         if (!nocow_ctx) {
4077                 spin_lock(&sctx->stat_lock);
4078                 sctx->stat.malloc_errors++;
4079                 spin_unlock(&sctx->stat_lock);
4080                 return -ENOMEM;
4081         }
4082
4083         scrub_pending_trans_workers_inc(sctx);
4084
4085         nocow_ctx->sctx = sctx;
4086         nocow_ctx->logical = logical;
4087         nocow_ctx->len = len;
4088         nocow_ctx->mirror_num = mirror_num;
4089         nocow_ctx->physical_for_dev_replace = physical_for_dev_replace;
4090         btrfs_init_work(&nocow_ctx->work, btrfs_scrubnc_helper,
4091                         copy_nocow_pages_worker, NULL, NULL);
4092         INIT_LIST_HEAD(&nocow_ctx->inodes);
4093         btrfs_queue_work(fs_info->scrub_nocow_workers,
4094                          &nocow_ctx->work);
4095
4096         return 0;
4097 }
4098
4099 static int record_inode_for_nocow(u64 inum, u64 offset, u64 root, void *ctx)
4100 {
4101         struct scrub_copy_nocow_ctx *nocow_ctx = ctx;
4102         struct scrub_nocow_inode *nocow_inode;
4103
4104         nocow_inode = kzalloc(sizeof(*nocow_inode), GFP_NOFS);
4105         if (!nocow_inode)
4106                 return -ENOMEM;
4107         nocow_inode->inum = inum;
4108         nocow_inode->offset = offset;
4109         nocow_inode->root = root;
4110         list_add_tail(&nocow_inode->list, &nocow_ctx->inodes);
4111         return 0;
4112 }
4113
4114 #define COPY_COMPLETE 1
4115
4116 static void copy_nocow_pages_worker(struct btrfs_work *work)
4117 {
4118         struct scrub_copy_nocow_ctx *nocow_ctx =
4119                 container_of(work, struct scrub_copy_nocow_ctx, work);
4120         struct scrub_ctx *sctx = nocow_ctx->sctx;
4121         u64 logical = nocow_ctx->logical;
4122         u64 len = nocow_ctx->len;
4123         int mirror_num = nocow_ctx->mirror_num;
4124         u64 physical_for_dev_replace = nocow_ctx->physical_for_dev_replace;
4125         int ret;
4126         struct btrfs_trans_handle *trans = NULL;
4127         struct btrfs_fs_info *fs_info;
4128         struct btrfs_path *path;
4129         struct btrfs_root *root;
4130         int not_written = 0;
4131
4132         fs_info = sctx->dev_root->fs_info;
4133         root = fs_info->extent_root;
4134
4135         path = btrfs_alloc_path();
4136         if (!path) {
4137                 spin_lock(&sctx->stat_lock);
4138                 sctx->stat.malloc_errors++;
4139                 spin_unlock(&sctx->stat_lock);
4140                 not_written = 1;
4141                 goto out;
4142         }
4143
4144         trans = btrfs_join_transaction(root);
4145         if (IS_ERR(trans)) {
4146                 not_written = 1;
4147                 goto out;
4148         }
4149
4150         ret = iterate_inodes_from_logical(logical, fs_info, path,
4151                                           record_inode_for_nocow, nocow_ctx);
4152         if (ret != 0 && ret != -ENOENT) {
4153                 btrfs_warn(fs_info, "iterate_inodes_from_logical() failed: log %llu, "
4154                         "phys %llu, len %llu, mir %u, ret %d",
4155                         logical, physical_for_dev_replace, len, mirror_num,
4156                         ret);
4157                 not_written = 1;
4158                 goto out;
4159         }
4160
4161         btrfs_end_transaction(trans, root);
4162         trans = NULL;
4163         while (!list_empty(&nocow_ctx->inodes)) {
4164                 struct scrub_nocow_inode *entry;
4165                 entry = list_first_entry(&nocow_ctx->inodes,
4166                                          struct scrub_nocow_inode,
4167                                          list);
4168                 list_del_init(&entry->list);
4169                 ret = copy_nocow_pages_for_inode(entry->inum, entry->offset,
4170                                                  entry->root, nocow_ctx);
4171                 kfree(entry);
4172                 if (ret == COPY_COMPLETE) {
4173                         ret = 0;
4174                         break;
4175                 } else if (ret) {
4176                         break;
4177                 }
4178         }
4179 out:
4180         while (!list_empty(&nocow_ctx->inodes)) {
4181                 struct scrub_nocow_inode *entry;
4182                 entry = list_first_entry(&nocow_ctx->inodes,
4183                                          struct scrub_nocow_inode,
4184                                          list);
4185                 list_del_init(&entry->list);
4186                 kfree(entry);
4187         }
4188         if (trans && !IS_ERR(trans))
4189                 btrfs_end_transaction(trans, root);
4190         if (not_written)
4191                 btrfs_dev_replace_stats_inc(&fs_info->dev_replace.
4192                                             num_uncorrectable_read_errors);
4193
4194         btrfs_free_path(path);
4195         kfree(nocow_ctx);
4196
4197         scrub_pending_trans_workers_dec(sctx);
4198 }
4199
4200 static int check_extent_to_block(struct inode *inode, u64 start, u64 len,
4201                                  u64 logical)
4202 {
4203         struct extent_state *cached_state = NULL;
4204         struct btrfs_ordered_extent *ordered;
4205         struct extent_io_tree *io_tree;
4206         struct extent_map *em;
4207         u64 lockstart = start, lockend = start + len - 1;
4208         int ret = 0;
4209
4210         io_tree = &BTRFS_I(inode)->io_tree;
4211
4212         lock_extent_bits(io_tree, lockstart, lockend, &cached_state);
4213         ordered = btrfs_lookup_ordered_range(inode, lockstart, len);
4214         if (ordered) {
4215                 btrfs_put_ordered_extent(ordered);
4216                 ret = 1;
4217                 goto out_unlock;
4218         }
4219
4220         em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
4221         if (IS_ERR(em)) {
4222                 ret = PTR_ERR(em);
4223                 goto out_unlock;
4224         }
4225
4226         /*
4227          * This extent does not actually cover the logical extent anymore,
4228          * move on to the next inode.
4229          */
4230         if (em->block_start > logical ||
4231             em->block_start + em->block_len < logical + len) {
4232                 free_extent_map(em);
4233                 ret = 1;
4234                 goto out_unlock;
4235         }
4236         free_extent_map(em);
4237
4238 out_unlock:
4239         unlock_extent_cached(io_tree, lockstart, lockend, &cached_state,
4240                              GFP_NOFS);
4241         return ret;
4242 }
4243
4244 static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root,
4245                                       struct scrub_copy_nocow_ctx *nocow_ctx)
4246 {
4247         struct btrfs_fs_info *fs_info = nocow_ctx->sctx->dev_root->fs_info;
4248         struct btrfs_key key;
4249         struct inode *inode;
4250         struct page *page;
4251         struct btrfs_root *local_root;
4252         struct extent_io_tree *io_tree;
4253         u64 physical_for_dev_replace;
4254         u64 nocow_ctx_logical;
4255         u64 len = nocow_ctx->len;
4256         unsigned long index;
4257         int srcu_index;
4258         int ret = 0;
4259         int err = 0;
4260
4261         key.objectid = root;
4262         key.type = BTRFS_ROOT_ITEM_KEY;
4263         key.offset = (u64)-1;
4264
4265         srcu_index = srcu_read_lock(&fs_info->subvol_srcu);
4266
4267         local_root = btrfs_read_fs_root_no_name(fs_info, &key);
4268         if (IS_ERR(local_root)) {
4269                 srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
4270                 return PTR_ERR(local_root);
4271         }
4272
4273         key.type = BTRFS_INODE_ITEM_KEY;
4274         key.objectid = inum;
4275         key.offset = 0;
4276         inode = btrfs_iget(fs_info->sb, &key, local_root, NULL);
4277         srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
4278         if (IS_ERR(inode))
4279                 return PTR_ERR(inode);
4280
4281         /* Avoid truncate/dio/punch hole.. */
4282         mutex_lock(&inode->i_mutex);
4283         inode_dio_wait(inode);
4284
4285         physical_for_dev_replace = nocow_ctx->physical_for_dev_replace;
4286         io_tree = &BTRFS_I(inode)->io_tree;
4287         nocow_ctx_logical = nocow_ctx->logical;
4288
4289         ret = check_extent_to_block(inode, offset, len, nocow_ctx_logical);
4290         if (ret) {
4291                 ret = ret > 0 ? 0 : ret;
4292                 goto out;
4293         }
4294
4295         while (len >= PAGE_CACHE_SIZE) {
4296                 index = offset >> PAGE_CACHE_SHIFT;
4297 again:
4298                 page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
4299                 if (!page) {
4300                         btrfs_err(fs_info, "find_or_create_page() failed");
4301                         ret = -ENOMEM;
4302                         goto out;
4303                 }
4304
4305                 if (PageUptodate(page)) {
4306                         if (PageDirty(page))
4307                                 goto next_page;
4308                 } else {
4309                         ClearPageError(page);
4310                         err = extent_read_full_page(io_tree, page,
4311                                                            btrfs_get_extent,
4312                                                            nocow_ctx->mirror_num);
4313                         if (err) {
4314                                 ret = err;
4315                                 goto next_page;
4316                         }
4317
4318                         lock_page(page);
4319                         /*
4320                          * If the page has been remove from the page cache,
4321                          * the data on it is meaningless, because it may be
4322                          * old one, the new data may be written into the new
4323                          * page in the page cache.
4324                          */
4325                         if (page->mapping != inode->i_mapping) {
4326                                 unlock_page(page);
4327                                 page_cache_release(page);
4328                                 goto again;
4329                         }
4330                         if (!PageUptodate(page)) {
4331                                 ret = -EIO;
4332                                 goto next_page;
4333                         }
4334                 }
4335
4336                 ret = check_extent_to_block(inode, offset, len,
4337                                             nocow_ctx_logical);
4338                 if (ret) {
4339                         ret = ret > 0 ? 0 : ret;
4340                         goto next_page;
4341                 }
4342
4343                 err = write_page_nocow(nocow_ctx->sctx,
4344                                        physical_for_dev_replace, page);
4345                 if (err)
4346                         ret = err;
4347 next_page:
4348                 unlock_page(page);
4349                 page_cache_release(page);
4350
4351                 if (ret)
4352                         break;
4353
4354                 offset += PAGE_CACHE_SIZE;
4355                 physical_for_dev_replace += PAGE_CACHE_SIZE;
4356                 nocow_ctx_logical += PAGE_CACHE_SIZE;
4357                 len -= PAGE_CACHE_SIZE;
4358         }
4359         ret = COPY_COMPLETE;
4360 out:
4361         mutex_unlock(&inode->i_mutex);
4362         iput(inode);
4363         return ret;
4364 }
4365
4366 static int write_page_nocow(struct scrub_ctx *sctx,
4367                             u64 physical_for_dev_replace, struct page *page)
4368 {
4369         struct bio *bio;
4370         struct btrfs_device *dev;
4371         int ret;
4372
4373         dev = sctx->wr_ctx.tgtdev;
4374         if (!dev)
4375                 return -EIO;
4376         if (!dev->bdev) {
4377                 btrfs_warn_rl(dev->dev_root->fs_info,
4378                         "scrub write_page_nocow(bdev == NULL) is unexpected");
4379                 return -EIO;
4380         }
4381         bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
4382         if (!bio) {
4383                 spin_lock(&sctx->stat_lock);
4384                 sctx->stat.malloc_errors++;
4385                 spin_unlock(&sctx->stat_lock);
4386                 return -ENOMEM;
4387         }
4388         bio->bi_iter.bi_size = 0;
4389         bio->bi_iter.bi_sector = physical_for_dev_replace >> 9;
4390         bio->bi_bdev = dev->bdev;
4391         ret = bio_add_page(bio, page, PAGE_CACHE_SIZE, 0);
4392         if (ret != PAGE_CACHE_SIZE) {
4393 leave_with_eio:
4394                 bio_put(bio);
4395                 btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
4396                 return -EIO;
4397         }
4398
4399         if (btrfsic_submit_bio_wait(WRITE_SYNC, bio))
4400                 goto leave_with_eio;
4401
4402         bio_put(bio);
4403         return 0;
4404 }