fs/btrfs/scrub.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2011, 2012 STRATO.  All rights reserved.
   4  */
   5
   6 #include <linux/blkdev.h>
   7 #include <linux/ratelimit.h>
   8 #include <linux/sched/mm.h>
   9 #include <crypto/hash.h>
  10 #include "ctree.h"
  11 #include "discard.h"
  12 #include "volumes.h"
  13 #include "disk-io.h"
  14 #include "ordered-data.h"
  15 #include "transaction.h"
  16 #include "backref.h"
  17 #include "extent_io.h"
  18 #include "dev-replace.h"
  19 #include "raid56.h"
  20 #include "block-group.h"
  21 #include "zoned.h"
  22 #include "fs.h"
  23 #include "accessors.h"
  24 #include "file-item.h"
  25 #include "scrub.h"
  26 #include "raid-stripe-tree.h"
  27
  28 /*
  29  * This is only the first step towards a full-features scrub. It reads all
  30  * extent and super block and verifies the checksums. In case a bad checksum
  31  * is found or the extent cannot be read, good data will be written back if
  32  * any can be found.
  33  *
  34  * Future enhancements:
  35  *  - In case an unrepairable extent is encountered, track which files are
  36  *    affected and report them
  37  *  - track and record media errors, throw out bad devices
  38  *  - add a mode to also read unallocated space
  39  */
  40
  41 struct scrub_ctx;
  42
  43 /*
  44  * The following value only influences the performance.
  45  *
  46  * This determines how many stripes would be submitted in one go,
  47  * which is 512KiB (BTRFS_STRIPE_LEN * SCRUB_STRIPES_PER_GROUP).
  48  */
  49 #define SCRUB_STRIPES_PER_GROUP         8
  50
  51 /*
  52  * How many groups we have for each sctx.
  53  *
  54  * This would be 8M per device, the same value as the old scrub in-flight bios
  55  * size limit.
  56  */
  57 #define SCRUB_GROUPS_PER_SCTX           16
  58
  59 #define SCRUB_TOTAL_STRIPES             (SCRUB_GROUPS_PER_SCTX * SCRUB_STRIPES_PER_GROUP)
  60
  61 /*
  62  * The following value times PAGE_SIZE needs to be large enough to match the
  63  * largest node/leaf/sector size that shall be supported.
  64  */
  65 #define SCRUB_MAX_SECTORS_PER_BLOCK     (BTRFS_MAX_METADATA_BLOCKSIZE / SZ_4K)
  66
  67 /* Represent one sector and its needed info to verify the content. */
  68 struct scrub_sector_verification {
  69         bool is_metadata;
  70
  71         union {
  72                 /*
  73                  * Csum pointer for data csum verification.  Should point to a
  74                  * sector csum inside scrub_stripe::csums.
  75                  *
  76                  * NULL if this data sector has no csum.
  77                  */
  78                 u8 *csum;
  79
  80                 /*
  81                  * Extra info for metadata verification.  All sectors inside a
  82                  * tree block share the same generation.
  83                  */
  84                 u64 generation;
  85         };
  86 };
  87
  88 enum scrub_stripe_flags {
  89         /* Set when @mirror_num, @dev, @physical and @logical are set. */
  90         SCRUB_STRIPE_FLAG_INITIALIZED,
  91
  92         /* Set when the read-repair is finished. */
  93         SCRUB_STRIPE_FLAG_REPAIR_DONE,
  94
  95         /*
  96          * Set for data stripes if it's triggered from P/Q stripe.
  97          * During such scrub, we should not report errors in data stripes, nor
  98          * update the accounting.
  99          */
 100         SCRUB_STRIPE_FLAG_NO_REPORT,
 101 };
 102
 103 #define SCRUB_STRIPE_PAGES              (BTRFS_STRIPE_LEN / PAGE_SIZE)
 104
 105 /*
 106  * Represent one contiguous range with a length of BTRFS_STRIPE_LEN.
 107  */
 108 struct scrub_stripe {
 109         struct scrub_ctx *sctx;
 110         struct btrfs_block_group *bg;
 111
 112         struct page *pages[SCRUB_STRIPE_PAGES];
 113         struct scrub_sector_verification *sectors;
 114
 115         struct btrfs_device *dev;
 116         u64 logical;
 117         u64 physical;
 118
 119         u16 mirror_num;
 120
 121         /* Should be BTRFS_STRIPE_LEN / sectorsize. */
 122         u16 nr_sectors;
 123
 124         /*
 125          * How many data/meta extents are in this stripe.  Only for scrub status
 126          * reporting purposes.
 127          */
 128         u16 nr_data_extents;
 129         u16 nr_meta_extents;
 130
 131         atomic_t pending_io;
 132         wait_queue_head_t io_wait;
 133         wait_queue_head_t repair_wait;
 134
 135         /*
 136          * Indicate the states of the stripe.  Bits are defined in
 137          * scrub_stripe_flags enum.
 138          */
 139         unsigned long state;
 140
 141         /* Indicate which sectors are covered by extent items. */
 142         unsigned long extent_sector_bitmap;
 143
 144         /*
 145          * The errors hit during the initial read of the stripe.
 146          *
 147          * Would be utilized for error reporting and repair.
 148          *
 149          * The remaining init_nr_* records the number of errors hit, only used
 150          * by error reporting.
 151          */
 152         unsigned long init_error_bitmap;
 153         unsigned int init_nr_io_errors;
 154         unsigned int init_nr_csum_errors;
 155         unsigned int init_nr_meta_errors;
 156
 157         /*
 158          * The following error bitmaps are all for the current status.
 159          * Every time we submit a new read, these bitmaps may be updated.
 160          *
 161          * error_bitmap = io_error_bitmap | csum_error_bitmap | meta_error_bitmap;
 162          *
 163          * IO and csum errors can happen for both metadata and data.
 164          */
 165         unsigned long error_bitmap;
 166         unsigned long io_error_bitmap;
 167         unsigned long csum_error_bitmap;
 168         unsigned long meta_error_bitmap;
 169
 170         /* For writeback (repair or replace) error reporting. */
 171         unsigned long write_error_bitmap;
 172
 173         /* Writeback can be concurrent, thus we need to protect the bitmap. */
 174         spinlock_t write_error_lock;
 175
 176         /*
 177          * Checksum for the whole stripe if this stripe is inside a data block
 178          * group.
 179          */
 180         u8 *csums;
 181
 182         struct work_struct work;
 183 };
 184
 185 struct scrub_ctx {
 186         struct scrub_stripe     stripes[SCRUB_TOTAL_STRIPES];
 187         struct scrub_stripe     *raid56_data_stripes;
 188         struct btrfs_fs_info    *fs_info;
 189         struct btrfs_path       extent_path;
 190         struct btrfs_path       csum_path;
 191         int                     first_free;
 192         int                     cur_stripe;
 193         atomic_t                cancel_req;
 194         int                     readonly;
 195
 196         /* State of IO submission throttling affecting the associated device */
 197         ktime_t                 throttle_deadline;
 198         u64                     throttle_sent;
 199
 200         int                     is_dev_replace;
 201         u64                     write_pointer;
 202
 203         struct mutex            wr_lock;
 204         struct btrfs_device     *wr_tgtdev;
 205
 206         /*
 207          * statistics
 208          */
 209         struct btrfs_scrub_progress stat;
 210         spinlock_t              stat_lock;
 211
 212         /*
 213          * Use a ref counter to avoid use-after-free issues. Scrub workers
 214          * decrement bios_in_flight and workers_pending and then do a wakeup
 215          * on the list_wait wait queue. We must ensure the main scrub task
 216          * doesn't free the scrub context before or while the workers are
 217          * doing the wakeup() call.
 218          */
 219         refcount_t              refs;
 220 };
 221
 222 struct scrub_warning {
 223         struct btrfs_path       *path;
 224         u64                     extent_item_size;
 225         const char              *errstr;
 226         u64                     physical;
 227         u64                     logical;
 228         struct btrfs_device     *dev;
 229 };
 230
 231 static void release_scrub_stripe(struct scrub_stripe *stripe)
 232 {
 233         if (!stripe)
 234                 return;
 235
 236         for (int i = 0; i < SCRUB_STRIPE_PAGES; i++) {
 237                 if (stripe->pages[i])
 238                         __free_page(stripe->pages[i]);
 239                 stripe->pages[i] = NULL;
 240         }
 241         kfree(stripe->sectors);
 242         kfree(stripe->csums);
 243         stripe->sectors = NULL;
 244         stripe->csums = NULL;
 245         stripe->sctx = NULL;
 246         stripe->state = 0;
 247 }
 248
 249 static int init_scrub_stripe(struct btrfs_fs_info *fs_info,
 250                              struct scrub_stripe *stripe)
 251 {
 252         int ret;
 253
 254         memset(stripe, 0, sizeof(*stripe));
 255
 256         stripe->nr_sectors = BTRFS_STRIPE_LEN >> fs_info->sectorsize_bits;
 257         stripe->state = 0;
 258
 259         init_waitqueue_head(&stripe->io_wait);
 260         init_waitqueue_head(&stripe->repair_wait);
 261         atomic_set(&stripe->pending_io, 0);
 262         spin_lock_init(&stripe->write_error_lock);
 263
 264         ret = btrfs_alloc_page_array(SCRUB_STRIPE_PAGES, stripe->pages, 0);
 265         if (ret < 0)
 266                 goto error;
 267
 268         stripe->sectors = kcalloc(stripe->nr_sectors,
 269                                   sizeof(struct scrub_sector_verification),
 270                                   GFP_KERNEL);
 271         if (!stripe->sectors)
 272                 goto error;
 273
 274         stripe->csums = kcalloc(BTRFS_STRIPE_LEN >> fs_info->sectorsize_bits,
 275                                 fs_info->csum_size, GFP_KERNEL);
 276         if (!stripe->csums)
 277                 goto error;
 278         return 0;
 279 error:
 280         release_scrub_stripe(stripe);
 281         return -ENOMEM;
 282 }
 283
 284 static void wait_scrub_stripe_io(struct scrub_stripe *stripe)
 285 {
 286         wait_event(stripe->io_wait, atomic_read(&stripe->pending_io) == 0);
 287 }
 288
 289 static void scrub_put_ctx(struct scrub_ctx *sctx);
 290
 291 static void __scrub_blocked_if_needed(struct btrfs_fs_info *fs_info)
 292 {
 293         while (atomic_read(&fs_info->scrub_pause_req)) {
 294                 mutex_unlock(&fs_info->scrub_lock);
 295                 wait_event(fs_info->scrub_pause_wait,
 296                    atomic_read(&fs_info->scrub_pause_req) == 0);
 297                 mutex_lock(&fs_info->scrub_lock);
 298         }
 299 }
 300
 301 static void scrub_pause_on(struct btrfs_fs_info *fs_info)
 302 {
 303         atomic_inc(&fs_info->scrubs_paused);
 304         wake_up(&fs_info->scrub_pause_wait);
 305 }
 306
 307 static void scrub_pause_off(struct btrfs_fs_info *fs_info)
 308 {
 309         mutex_lock(&fs_info->scrub_lock);
 310         __scrub_blocked_if_needed(fs_info);
 311         atomic_dec(&fs_info->scrubs_paused);
 312         mutex_unlock(&fs_info->scrub_lock);
 313
 314         wake_up(&fs_info->scrub_pause_wait);
 315 }
 316
 317 static void scrub_blocked_if_needed(struct btrfs_fs_info *fs_info)
 318 {
 319         scrub_pause_on(fs_info);
 320         scrub_pause_off(fs_info);
 321 }
 322
 323 static noinline_for_stack void scrub_free_ctx(struct scrub_ctx *sctx)
 324 {
 325         int i;
 326
 327         if (!sctx)
 328                 return;
 329
 330         for (i = 0; i < SCRUB_TOTAL_STRIPES; i++)
 331                 release_scrub_stripe(&sctx->stripes[i]);
 332
 333         kvfree(sctx);
 334 }
 335
 336 static void scrub_put_ctx(struct scrub_ctx *sctx)
 337 {
 338         if (refcount_dec_and_test(&sctx->refs))
 339                 scrub_free_ctx(sctx);
 340 }
 341
 342 static noinline_for_stack struct scrub_ctx *scrub_setup_ctx(
 343                 struct btrfs_fs_info *fs_info, int is_dev_replace)
 344 {
 345         struct scrub_ctx *sctx;
 346         int             i;
 347
 348         /* Since sctx has inline 128 stripes, it can go beyond 64K easily.  Use
 349          * kvzalloc().
 350          */
 351         sctx = kvzalloc(sizeof(*sctx), GFP_KERNEL);
 352         if (!sctx)
 353                 goto nomem;
 354         refcount_set(&sctx->refs, 1);
 355         sctx->is_dev_replace = is_dev_replace;
 356         sctx->fs_info = fs_info;
 357         sctx->extent_path.search_commit_root = 1;
 358         sctx->extent_path.skip_locking = 1;
 359         sctx->csum_path.search_commit_root = 1;
 360         sctx->csum_path.skip_locking = 1;
 361         for (i = 0; i < SCRUB_TOTAL_STRIPES; i++) {
 362                 int ret;
 363
 364                 ret = init_scrub_stripe(fs_info, &sctx->stripes[i]);
 365                 if (ret < 0)
 366                         goto nomem;
 367                 sctx->stripes[i].sctx = sctx;
 368         }
 369         sctx->first_free = 0;
 370         atomic_set(&sctx->cancel_req, 0);
 371
 372         spin_lock_init(&sctx->stat_lock);
 373         sctx->throttle_deadline = 0;
 374
 375         mutex_init(&sctx->wr_lock);
 376         if (is_dev_replace) {
 377                 WARN_ON(!fs_info->dev_replace.tgtdev);
 378                 sctx->wr_tgtdev = fs_info->dev_replace.tgtdev;
 379         }
 380
 381         return sctx;
 382
 383 nomem:
 384         scrub_free_ctx(sctx);
 385         return ERR_PTR(-ENOMEM);
 386 }
 387
 388 static int scrub_print_warning_inode(u64 inum, u64 offset, u64 num_bytes,
 389                                      u64 root, void *warn_ctx)
 390 {
 391         u32 nlink;
 392         int ret;
 393         int i;
 394         unsigned nofs_flag;
 395         struct extent_buffer *eb;
 396         struct btrfs_inode_item *inode_item;
 397         struct scrub_warning *swarn = warn_ctx;
 398         struct btrfs_fs_info *fs_info = swarn->dev->fs_info;
 399         struct inode_fs_paths *ipath = NULL;
 400         struct btrfs_root *local_root;
 401         struct btrfs_key key;
 402
 403         local_root = btrfs_get_fs_root(fs_info, root, true);
 404         if (IS_ERR(local_root)) {
 405                 ret = PTR_ERR(local_root);
 406                 goto err;
 407         }
 408
 409         /*
 410          * this makes the path point to (inum INODE_ITEM ioff)
 411          */
 412         key.objectid = inum;
 413         key.type = BTRFS_INODE_ITEM_KEY;
 414         key.offset = 0;
 415
 416         ret = btrfs_search_slot(NULL, local_root, &key, swarn->path, 0, 0);
 417         if (ret) {
 418                 btrfs_put_root(local_root);
 419                 btrfs_release_path(swarn->path);
 420                 goto err;
 421         }
 422
 423         eb = swarn->path->nodes[0];
 424         inode_item = btrfs_item_ptr(eb, swarn->path->slots[0],
 425                                         struct btrfs_inode_item);
 426         nlink = btrfs_inode_nlink(eb, inode_item);
 427         btrfs_release_path(swarn->path);
 428
 429         /*
 430          * init_path might indirectly call vmalloc, or use GFP_KERNEL. Scrub
 431          * uses GFP_NOFS in this context, so we keep it consistent but it does
 432          * not seem to be strictly necessary.
 433          */
 434         nofs_flag = memalloc_nofs_save();
 435         ipath = init_ipath(4096, local_root, swarn->path);
 436         memalloc_nofs_restore(nofs_flag);
 437         if (IS_ERR(ipath)) {
 438                 btrfs_put_root(local_root);
 439                 ret = PTR_ERR(ipath);
 440                 ipath = NULL;
 441                 goto err;
 442         }
 443         ret = paths_from_inode(inum, ipath);
 444
 445         if (ret < 0)
 446                 goto err;
 447
 448         /*
 449          * we deliberately ignore the bit ipath might have been too small to
 450          * hold all of the paths here
 451          */
 452         for (i = 0; i < ipath->fspath->elem_cnt; ++i)
 453                 btrfs_warn_in_rcu(fs_info,
 454 "%s at logical %llu on dev %s, physical %llu, root %llu, inode %llu, offset %llu, length %u, links %u (path: %s)",
 455                                   swarn->errstr, swarn->logical,
 456                                   btrfs_dev_name(swarn->dev),
 457                                   swarn->physical,
 458                                   root, inum, offset,
 459                                   fs_info->sectorsize, nlink,
 460                                   (char *)(unsigned long)ipath->fspath->val[i]);
 461
 462         btrfs_put_root(local_root);
 463         free_ipath(ipath);
 464         return 0;
 465
 466 err:
 467         btrfs_warn_in_rcu(fs_info,
 468                           "%s at logical %llu on dev %s, physical %llu, root %llu, inode %llu, offset %llu: path resolving failed with ret=%d",
 469                           swarn->errstr, swarn->logical,
 470                           btrfs_dev_name(swarn->dev),
 471                           swarn->physical,
 472                           root, inum, offset, ret);
 473
 474         free_ipath(ipath);
 475         return 0;
 476 }
 477
 478 static void scrub_print_common_warning(const char *errstr, struct btrfs_device *dev,
 479                                        bool is_super, u64 logical, u64 physical)
 480 {
 481         struct btrfs_fs_info *fs_info = dev->fs_info;
 482         struct btrfs_path *path;
 483         struct btrfs_key found_key;
 484         struct extent_buffer *eb;
 485         struct btrfs_extent_item *ei;
 486         struct scrub_warning swarn;
 487         u64 flags = 0;
 488         u32 item_size;
 489         int ret;
 490
 491         /* Super block error, no need to search extent tree. */
 492         if (is_super) {
 493                 btrfs_warn_in_rcu(fs_info, "%s on device %s, physical %llu",
 494                                   errstr, btrfs_dev_name(dev), physical);
 495                 return;
 496         }
 497         path = btrfs_alloc_path();
 498         if (!path)
 499                 return;
 500
 501         swarn.physical = physical;
 502         swarn.logical = logical;
 503         swarn.errstr = errstr;
 504         swarn.dev = NULL;
 505
 506         ret = extent_from_logical(fs_info, swarn.logical, path, &found_key,
 507                                   &flags);
 508         if (ret < 0)
 509                 goto out;
 510
 511         swarn.extent_item_size = found_key.offset;
 512
 513         eb = path->nodes[0];
 514         ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
 515         item_size = btrfs_item_size(eb, path->slots[0]);
 516
 517         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
 518                 unsigned long ptr = 0;
 519                 u8 ref_level;
 520                 u64 ref_root;
 521
 522                 while (true) {
 523                         ret = tree_backref_for_extent(&ptr, eb, &found_key, ei,
 524                                                       item_size, &ref_root,
 525                                                       &ref_level);
 526                         if (ret < 0) {
 527                                 btrfs_warn(fs_info,
 528                                 "failed to resolve tree backref for logical %llu: %d",
 529                                                   swarn.logical, ret);
 530                                 break;
 531                         }
 532                         if (ret > 0)
 533                                 break;
 534                         btrfs_warn_in_rcu(fs_info,
 535 "%s at logical %llu on dev %s, physical %llu: metadata %s (level %d) in tree %llu",
 536                                 errstr, swarn.logical, btrfs_dev_name(dev),
 537                                 swarn.physical, (ref_level ? "node" : "leaf"),
 538                                 ref_level, ref_root);
 539                 }
 540                 btrfs_release_path(path);
 541         } else {
 542                 struct btrfs_backref_walk_ctx ctx = { 0 };
 543
 544                 btrfs_release_path(path);
 545
 546                 ctx.bytenr = found_key.objectid;
 547                 ctx.extent_item_pos = swarn.logical - found_key.objectid;
 548                 ctx.fs_info = fs_info;
 549
 550                 swarn.path = path;
 551                 swarn.dev = dev;
 552
 553                 iterate_extent_inodes(&ctx, true, scrub_print_warning_inode, &swarn);
 554         }
 555
 556 out:
 557         btrfs_free_path(path);
 558 }
 559
 560 static int fill_writer_pointer_gap(struct scrub_ctx *sctx, u64 physical)
 561 {
 562         int ret = 0;
 563         u64 length;
 564
 565         if (!btrfs_is_zoned(sctx->fs_info))
 566                 return 0;
 567
 568         if (!btrfs_dev_is_sequential(sctx->wr_tgtdev, physical))
 569                 return 0;
 570
 571         if (sctx->write_pointer < physical) {
 572                 length = physical - sctx->write_pointer;
 573
 574                 ret = btrfs_zoned_issue_zeroout(sctx->wr_tgtdev,
 575                                                 sctx->write_pointer, length);
 576                 if (!ret)
 577                         sctx->write_pointer = physical;
 578         }
 579         return ret;
 580 }
 581
 582 static struct page *scrub_stripe_get_page(struct scrub_stripe *stripe, int sector_nr)
 583 {
 584         struct btrfs_fs_info *fs_info = stripe->bg->fs_info;
 585         int page_index = (sector_nr << fs_info->sectorsize_bits) >> PAGE_SHIFT;
 586
 587         return stripe->pages[page_index];
 588 }
 589
 590 static unsigned int scrub_stripe_get_page_offset(struct scrub_stripe *stripe,
 591                                                  int sector_nr)
 592 {
 593         struct btrfs_fs_info *fs_info = stripe->bg->fs_info;
 594
 595         return offset_in_page(sector_nr << fs_info->sectorsize_bits);
 596 }
 597
 598 static void scrub_verify_one_metadata(struct scrub_stripe *stripe, int sector_nr)
 599 {
 600         struct btrfs_fs_info *fs_info = stripe->bg->fs_info;
 601         const u32 sectors_per_tree = fs_info->nodesize >> fs_info->sectorsize_bits;
 602         const u64 logical = stripe->logical + (sector_nr << fs_info->sectorsize_bits);
 603         const struct page *first_page = scrub_stripe_get_page(stripe, sector_nr);
 604         const unsigned int first_off = scrub_stripe_get_page_offset(stripe, sector_nr);
 605         SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
 606         u8 on_disk_csum[BTRFS_CSUM_SIZE];
 607         u8 calculated_csum[BTRFS_CSUM_SIZE];
 608         struct btrfs_header *header;
 609
 610         /*
 611          * Here we don't have a good way to attach the pages (and subpages)
 612          * to a dummy extent buffer, thus we have to directly grab the members
 613          * from pages.
 614          */
 615         header = (struct btrfs_header *)(page_address(first_page) + first_off);
 616         memcpy(on_disk_csum, header->csum, fs_info->csum_size);
 617
 618         if (logical != btrfs_stack_header_bytenr(header)) {
 619                 bitmap_set(&stripe->csum_error_bitmap, sector_nr, sectors_per_tree);
 620                 bitmap_set(&stripe->error_bitmap, sector_nr, sectors_per_tree);
 621                 btrfs_warn_rl(fs_info,
 622                 "tree block %llu mirror %u has bad bytenr, has %llu want %llu",
 623                               logical, stripe->mirror_num,
 624                               btrfs_stack_header_bytenr(header), logical);
 625                 return;
 626         }
 627         if (memcmp(header->fsid, fs_info->fs_devices->metadata_uuid,
 628                    BTRFS_FSID_SIZE) != 0) {
 629                 bitmap_set(&stripe->meta_error_bitmap, sector_nr, sectors_per_tree);
 630                 bitmap_set(&stripe->error_bitmap, sector_nr, sectors_per_tree);
 631                 btrfs_warn_rl(fs_info,
 632                 "tree block %llu mirror %u has bad fsid, has %pU want %pU",
 633                               logical, stripe->mirror_num,
 634                               header->fsid, fs_info->fs_devices->fsid);
 635                 return;
 636         }
 637         if (memcmp(header->chunk_tree_uuid, fs_info->chunk_tree_uuid,
 638                    BTRFS_UUID_SIZE) != 0) {
 639                 bitmap_set(&stripe->meta_error_bitmap, sector_nr, sectors_per_tree);
 640                 bitmap_set(&stripe->error_bitmap, sector_nr, sectors_per_tree);
 641                 btrfs_warn_rl(fs_info,
 642                 "tree block %llu mirror %u has bad chunk tree uuid, has %pU want %pU",
 643                               logical, stripe->mirror_num,
 644                               header->chunk_tree_uuid, fs_info->chunk_tree_uuid);
 645                 return;
 646         }
 647
 648         /* Now check tree block csum. */
 649         shash->tfm = fs_info->csum_shash;
 650         crypto_shash_init(shash);
 651         crypto_shash_update(shash, page_address(first_page) + first_off +
 652                             BTRFS_CSUM_SIZE, fs_info->sectorsize - BTRFS_CSUM_SIZE);
 653
 654         for (int i = sector_nr + 1; i < sector_nr + sectors_per_tree; i++) {
 655                 struct page *page = scrub_stripe_get_page(stripe, i);
 656                 unsigned int page_off = scrub_stripe_get_page_offset(stripe, i);
 657
 658                 crypto_shash_update(shash, page_address(page) + page_off,
 659                                     fs_info->sectorsize);
 660         }
 661
 662         crypto_shash_final(shash, calculated_csum);
 663         if (memcmp(calculated_csum, on_disk_csum, fs_info->csum_size) != 0) {
 664                 bitmap_set(&stripe->meta_error_bitmap, sector_nr, sectors_per_tree);
 665                 bitmap_set(&stripe->error_bitmap, sector_nr, sectors_per_tree);
 666                 btrfs_warn_rl(fs_info,
 667                 "tree block %llu mirror %u has bad csum, has " CSUM_FMT " want " CSUM_FMT,
 668                               logical, stripe->mirror_num,
 669                               CSUM_FMT_VALUE(fs_info->csum_size, on_disk_csum),
 670                               CSUM_FMT_VALUE(fs_info->csum_size, calculated_csum));
 671                 return;
 672         }
 673         if (stripe->sectors[sector_nr].generation !=
 674             btrfs_stack_header_generation(header)) {
 675                 bitmap_set(&stripe->meta_error_bitmap, sector_nr, sectors_per_tree);
 676                 bitmap_set(&stripe->error_bitmap, sector_nr, sectors_per_tree);
 677                 btrfs_warn_rl(fs_info,
 678                 "tree block %llu mirror %u has bad generation, has %llu want %llu",
 679                               logical, stripe->mirror_num,
 680                               btrfs_stack_header_generation(header),
 681                               stripe->sectors[sector_nr].generation);
 682                 return;
 683         }
 684         bitmap_clear(&stripe->error_bitmap, sector_nr, sectors_per_tree);
 685         bitmap_clear(&stripe->csum_error_bitmap, sector_nr, sectors_per_tree);
 686         bitmap_clear(&stripe->meta_error_bitmap, sector_nr, sectors_per_tree);
 687 }
 688
 689 static void scrub_verify_one_sector(struct scrub_stripe *stripe, int sector_nr)
 690 {
 691         struct btrfs_fs_info *fs_info = stripe->bg->fs_info;
 692         struct scrub_sector_verification *sector = &stripe->sectors[sector_nr];
 693         const u32 sectors_per_tree = fs_info->nodesize >> fs_info->sectorsize_bits;
 694         struct page *page = scrub_stripe_get_page(stripe, sector_nr);
 695         unsigned int pgoff = scrub_stripe_get_page_offset(stripe, sector_nr);
 696         u8 csum_buf[BTRFS_CSUM_SIZE];
 697         int ret;
 698
 699         ASSERT(sector_nr >= 0 && sector_nr < stripe->nr_sectors);
 700
 701         /* Sector not utilized, skip it. */
 702         if (!test_bit(sector_nr, &stripe->extent_sector_bitmap))
 703                 return;
 704
 705         /* IO error, no need to check. */
 706         if (test_bit(sector_nr, &stripe->io_error_bitmap))
 707                 return;
 708
 709         /* Metadata, verify the full tree block. */
 710         if (sector->is_metadata) {
 711                 /*
 712                  * Check if the tree block crosses the stripe boundary.  If
 713                  * crossed the boundary, we cannot verify it but only give a
 714                  * warning.
 715                  *
 716                  * This can only happen on a very old filesystem where chunks
 717                  * are not ensured to be stripe aligned.
 718                  */
 719                 if (unlikely(sector_nr + sectors_per_tree > stripe->nr_sectors)) {
 720                         btrfs_warn_rl(fs_info,
 721                         "tree block at %llu crosses stripe boundary %llu",
 722                                       stripe->logical +
 723                                       (sector_nr << fs_info->sectorsize_bits),
 724                                       stripe->logical);
 725                         return;
 726                 }
 727                 scrub_verify_one_metadata(stripe, sector_nr);
 728                 return;
 729         }
 730
 731         /*
 732          * Data is easier, we just verify the data csum (if we have it).  For
 733          * cases without csum, we have no other choice but to trust it.
 734          */
 735         if (!sector->csum) {
 736                 clear_bit(sector_nr, &stripe->error_bitmap);
 737                 return;
 738         }
 739
 740         ret = btrfs_check_sector_csum(fs_info, page, pgoff, csum_buf, sector->csum);
 741         if (ret < 0) {
 742                 set_bit(sector_nr, &stripe->csum_error_bitmap);
 743                 set_bit(sector_nr, &stripe->error_bitmap);
 744         } else {
 745                 clear_bit(sector_nr, &stripe->csum_error_bitmap);
 746                 clear_bit(sector_nr, &stripe->error_bitmap);
 747         }
 748 }
 749
 750 /* Verify specified sectors of a stripe. */
 751 static void scrub_verify_one_stripe(struct scrub_stripe *stripe, unsigned long bitmap)
 752 {
 753         struct btrfs_fs_info *fs_info = stripe->bg->fs_info;
 754         const u32 sectors_per_tree = fs_info->nodesize >> fs_info->sectorsize_bits;
 755         int sector_nr;
 756
 757         for_each_set_bit(sector_nr, &bitmap, stripe->nr_sectors) {
 758                 scrub_verify_one_sector(stripe, sector_nr);
 759                 if (stripe->sectors[sector_nr].is_metadata)
 760                         sector_nr += sectors_per_tree - 1;
 761         }
 762 }
 763
 764 static int calc_sector_number(struct scrub_stripe *stripe, struct bio_vec *first_bvec)
 765 {
 766         int i;
 767
 768         for (i = 0; i < stripe->nr_sectors; i++) {
 769                 if (scrub_stripe_get_page(stripe, i) == first_bvec->bv_page &&
 770                     scrub_stripe_get_page_offset(stripe, i) == first_bvec->bv_offset)
 771                         break;
 772         }
 773         ASSERT(i < stripe->nr_sectors);
 774         return i;
 775 }
 776
 777 /*
 778  * Repair read is different to the regular read:
 779  *
 780  * - Only reads the failed sectors
 781  * - May have extra blocksize limits
 782  */
 783 static void scrub_repair_read_endio(struct btrfs_bio *bbio)
 784 {
 785         struct scrub_stripe *stripe = bbio->private;
 786         struct btrfs_fs_info *fs_info = stripe->bg->fs_info;
 787         struct bio_vec *bvec;
 788         int sector_nr = calc_sector_number(stripe, bio_first_bvec_all(&bbio->bio));
 789         u32 bio_size = 0;
 790         int i;
 791
 792         ASSERT(sector_nr < stripe->nr_sectors);
 793
 794         bio_for_each_bvec_all(bvec, &bbio->bio, i)
 795                 bio_size += bvec->bv_len;
 796
 797         if (bbio->bio.bi_status) {
 798                 bitmap_set(&stripe->io_error_bitmap, sector_nr,
 799                            bio_size >> fs_info->sectorsize_bits);
 800                 bitmap_set(&stripe->error_bitmap, sector_nr,
 801                            bio_size >> fs_info->sectorsize_bits);
 802         } else {
 803                 bitmap_clear(&stripe->io_error_bitmap, sector_nr,
 804                              bio_size >> fs_info->sectorsize_bits);
 805         }
 806         bio_put(&bbio->bio);
 807         if (atomic_dec_and_test(&stripe->pending_io))
 808                 wake_up(&stripe->io_wait);
 809 }
 810
 811 static int calc_next_mirror(int mirror, int num_copies)
 812 {
 813         ASSERT(mirror <= num_copies);
 814         return (mirror + 1 > num_copies) ? 1 : mirror + 1;
 815 }
 816
 817 static void scrub_stripe_submit_repair_read(struct scrub_stripe *stripe,
 818                                             int mirror, int blocksize, bool wait)
 819 {
 820         struct btrfs_fs_info *fs_info = stripe->bg->fs_info;
 821         struct btrfs_bio *bbio = NULL;
 822         const unsigned long old_error_bitmap = stripe->error_bitmap;
 823         int i;
 824
 825         ASSERT(stripe->mirror_num >= 1);
 826         ASSERT(atomic_read(&stripe->pending_io) == 0);
 827
 828         for_each_set_bit(i, &old_error_bitmap, stripe->nr_sectors) {
 829                 struct page *page;
 830                 int pgoff;
 831                 int ret;
 832
 833                 page = scrub_stripe_get_page(stripe, i);
 834                 pgoff = scrub_stripe_get_page_offset(stripe, i);
 835
 836                 /* The current sector cannot be merged, submit the bio. */
 837                 if (bbio && ((i > 0 && !test_bit(i - 1, &stripe->error_bitmap)) ||
 838                              bbio->bio.bi_iter.bi_size >= blocksize)) {
 839                         ASSERT(bbio->bio.bi_iter.bi_size);
 840                         atomic_inc(&stripe->pending_io);
 841                         btrfs_submit_bio(bbio, mirror);
 842                         if (wait)
 843                                 wait_scrub_stripe_io(stripe);
 844                         bbio = NULL;
 845                 }
 846
 847                 if (!bbio) {
 848                         bbio = btrfs_bio_alloc(stripe->nr_sectors, REQ_OP_READ,
 849                                 fs_info, scrub_repair_read_endio, stripe);
 850                         bbio->bio.bi_iter.bi_sector = (stripe->logical +
 851                                 (i << fs_info->sectorsize_bits)) >> SECTOR_SHIFT;
 852                 }
 853
 854                 ret = bio_add_page(&bbio->bio, page, fs_info->sectorsize, pgoff);
 855                 ASSERT(ret == fs_info->sectorsize);
 856         }
 857         if (bbio) {
 858                 ASSERT(bbio->bio.bi_iter.bi_size);
 859                 atomic_inc(&stripe->pending_io);
 860                 btrfs_submit_bio(bbio, mirror);
 861                 if (wait)
 862                         wait_scrub_stripe_io(stripe);
 863         }
 864 }
 865
 866 static void scrub_stripe_report_errors(struct scrub_ctx *sctx,
 867                                        struct scrub_stripe *stripe)
 868 {
 869         static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL,
 870                                       DEFAULT_RATELIMIT_BURST);
 871         struct btrfs_fs_info *fs_info = sctx->fs_info;
 872         struct btrfs_device *dev = NULL;
 873         u64 physical = 0;
 874         int nr_data_sectors = 0;
 875         int nr_meta_sectors = 0;
 876         int nr_nodatacsum_sectors = 0;
 877         int nr_repaired_sectors = 0;
 878         int sector_nr;
 879
 880         if (test_bit(SCRUB_STRIPE_FLAG_NO_REPORT, &stripe->state))
 881                 return;
 882
 883         /*
 884          * Init needed infos for error reporting.
 885          *
 886          * Although our scrub_stripe infrastructure is mostly based on btrfs_submit_bio()
 887          * thus no need for dev/physical, error reporting still needs dev and physical.
 888          */
 889         if (!bitmap_empty(&stripe->init_error_bitmap, stripe->nr_sectors)) {
 890                 u64 mapped_len = fs_info->sectorsize;
 891                 struct btrfs_io_context *bioc = NULL;
 892                 int stripe_index = stripe->mirror_num - 1;
 893                 int ret;
 894
 895                 /* For scrub, our mirror_num should always start at 1. */
 896                 ASSERT(stripe->mirror_num >= 1);
 897                 ret = btrfs_map_block(fs_info, BTRFS_MAP_GET_READ_MIRRORS,
 898                                       stripe->logical, &mapped_len, &bioc,
 899                                       NULL, NULL);
 900                 /*
 901                  * If we failed, dev will be NULL, and later detailed reports
 902                  * will just be skipped.
 903                  */
 904                 if (ret < 0)
 905                         goto skip;
 906                 physical = bioc->stripes[stripe_index].physical;
 907                 dev = bioc->stripes[stripe_index].dev;
 908                 btrfs_put_bioc(bioc);
 909         }
 910
 911 skip:
 912         for_each_set_bit(sector_nr, &stripe->extent_sector_bitmap, stripe->nr_sectors) {
 913                 bool repaired = false;
 914
 915                 if (stripe->sectors[sector_nr].is_metadata) {
 916                         nr_meta_sectors++;
 917                 } else {
 918                         nr_data_sectors++;
 919                         if (!stripe->sectors[sector_nr].csum)
 920                                 nr_nodatacsum_sectors++;
 921                 }
 922
 923                 if (test_bit(sector_nr, &stripe->init_error_bitmap) &&
 924                     !test_bit(sector_nr, &stripe->error_bitmap)) {
 925                         nr_repaired_sectors++;
 926                         repaired = true;
 927                 }
 928
 929                 /* Good sector from the beginning, nothing need to be done. */
 930                 if (!test_bit(sector_nr, &stripe->init_error_bitmap))
 931                         continue;
 932
 933                 /*
 934                  * Report error for the corrupted sectors.  If repaired, just
 935                  * output the message of repaired message.
 936                  */
 937                 if (repaired) {
 938                         if (dev) {
 939                                 btrfs_err_rl_in_rcu(fs_info,
 940                         "fixed up error at logical %llu on dev %s physical %llu",
 941                                             stripe->logical, btrfs_dev_name(dev),
 942                                             physical);
 943                         } else {
 944                                 btrfs_err_rl_in_rcu(fs_info,
 945                         "fixed up error at logical %llu on mirror %u",
 946                                             stripe->logical, stripe->mirror_num);
 947                         }
 948                         continue;
 949                 }
 950
 951                 /* The remaining are all for unrepaired. */
 952                 if (dev) {
 953                         btrfs_err_rl_in_rcu(fs_info,
 954         "unable to fixup (regular) error at logical %llu on dev %s physical %llu",
 955                                             stripe->logical, btrfs_dev_name(dev),
 956                                             physical);
 957                 } else {
 958                         btrfs_err_rl_in_rcu(fs_info,
 959         "unable to fixup (regular) error at logical %llu on mirror %u",
 960                                             stripe->logical, stripe->mirror_num);
 961                 }
 962
 963                 if (test_bit(sector_nr, &stripe->io_error_bitmap))
 964                         if (__ratelimit(&rs) && dev)
 965                                 scrub_print_common_warning("i/o error", dev, false,
 966                                                      stripe->logical, physical);
 967                 if (test_bit(sector_nr, &stripe->csum_error_bitmap))
 968                         if (__ratelimit(&rs) && dev)
 969                                 scrub_print_common_warning("checksum error", dev, false,
 970                                                      stripe->logical, physical);
 971                 if (test_bit(sector_nr, &stripe->meta_error_bitmap))
 972                         if (__ratelimit(&rs) && dev)
 973                                 scrub_print_common_warning("header error", dev, false,
 974                                                      stripe->logical, physical);
 975         }
 976
 977         spin_lock(&sctx->stat_lock);
 978         sctx->stat.data_extents_scrubbed += stripe->nr_data_extents;
 979         sctx->stat.tree_extents_scrubbed += stripe->nr_meta_extents;
 980         sctx->stat.data_bytes_scrubbed += nr_data_sectors << fs_info->sectorsize_bits;
 981         sctx->stat.tree_bytes_scrubbed += nr_meta_sectors << fs_info->sectorsize_bits;
 982         sctx->stat.no_csum += nr_nodatacsum_sectors;
 983         sctx->stat.read_errors += stripe->init_nr_io_errors;
 984         sctx->stat.csum_errors += stripe->init_nr_csum_errors;
 985         sctx->stat.verify_errors += stripe->init_nr_meta_errors;
 986         sctx->stat.uncorrectable_errors +=
 987                 bitmap_weight(&stripe->error_bitmap, stripe->nr_sectors);
 988         sctx->stat.corrected_errors += nr_repaired_sectors;
 989         spin_unlock(&sctx->stat_lock);
 990 }
 991
 992 static void scrub_write_sectors(struct scrub_ctx *sctx, struct scrub_stripe *stripe,
 993                                 unsigned long write_bitmap, bool dev_replace);
 994
 995 /*
 996  * The main entrance for all read related scrub work, including:
 997  *
 998  * - Wait for the initial read to finish
 999  * - Verify and locate any bad sectors
1000  * - Go through the remaining mirrors and try to read as large blocksize as
1001  *   possible
1002  * - Go through all mirrors (including the failed mirror) sector-by-sector
1003  * - Submit writeback for repaired sectors
1004  *
1005  * Writeback for dev-replace does not happen here, it needs extra
1006  * synchronization for zoned devices.
1007  */
1008 static void scrub_stripe_read_repair_worker(struct work_struct *work)
1009 {
1010         struct scrub_stripe *stripe = container_of(work, struct scrub_stripe, work);
1011         struct scrub_ctx *sctx = stripe->sctx;
1012         struct btrfs_fs_info *fs_info = sctx->fs_info;
1013         int num_copies = btrfs_num_copies(fs_info, stripe->bg->start,
1014                                           stripe->bg->length);
1015         unsigned long repaired;
1016         int mirror;
1017         int i;
1018
1019         ASSERT(stripe->mirror_num > 0);
1020
1021         wait_scrub_stripe_io(stripe);
1022         scrub_verify_one_stripe(stripe, stripe->extent_sector_bitmap);
1023         /* Save the initial failed bitmap for later repair and report usage. */
1024         stripe->init_error_bitmap = stripe->error_bitmap;
1025         stripe->init_nr_io_errors = bitmap_weight(&stripe->io_error_bitmap,
1026                                                   stripe->nr_sectors);
1027         stripe->init_nr_csum_errors = bitmap_weight(&stripe->csum_error_bitmap,
1028                                                     stripe->nr_sectors);
1029         stripe->init_nr_meta_errors = bitmap_weight(&stripe->meta_error_bitmap,
1030                                                     stripe->nr_sectors);
1031
1032         if (bitmap_empty(&stripe->init_error_bitmap, stripe->nr_sectors))
1033                 goto out;
1034
1035         /*
1036          * Try all remaining mirrors.
1037          *
1038          * Here we still try to read as large block as possible, as this is
1039          * faster and we have extra safety nets to rely on.
1040          */
1041         for (mirror = calc_next_mirror(stripe->mirror_num, num_copies);
1042              mirror != stripe->mirror_num;
1043              mirror = calc_next_mirror(mirror, num_copies)) {
1044                 const unsigned long old_error_bitmap = stripe->error_bitmap;
1045
1046                 scrub_stripe_submit_repair_read(stripe, mirror,
1047                                                 BTRFS_STRIPE_LEN, false);
1048                 wait_scrub_stripe_io(stripe);
1049                 scrub_verify_one_stripe(stripe, old_error_bitmap);
1050                 if (bitmap_empty(&stripe->error_bitmap, stripe->nr_sectors))
1051                         goto out;
1052         }
1053
1054         /*
1055          * Last safety net, try re-checking all mirrors, including the failed
1056          * one, sector-by-sector.
1057          *
1058          * As if one sector failed the drive's internal csum, the whole read
1059          * containing the offending sector would be marked as error.
1060          * Thus here we do sector-by-sector read.
1061          *
1062          * This can be slow, thus we only try it as the last resort.
1063          */
1064
1065         for (i = 0, mirror = stripe->mirror_num;
1066              i < num_copies;
1067              i++, mirror = calc_next_mirror(mirror, num_copies)) {
1068                 const unsigned long old_error_bitmap = stripe->error_bitmap;
1069
1070                 scrub_stripe_submit_repair_read(stripe, mirror,
1071                                                 fs_info->sectorsize, true);
1072                 wait_scrub_stripe_io(stripe);
1073                 scrub_verify_one_stripe(stripe, old_error_bitmap);
1074                 if (bitmap_empty(&stripe->error_bitmap, stripe->nr_sectors))
1075                         goto out;
1076         }
1077 out:
1078         /*
1079          * Submit the repaired sectors.  For zoned case, we cannot do repair
1080          * in-place, but queue the bg to be relocated.
1081          */
1082         bitmap_andnot(&repaired, &stripe->init_error_bitmap, &stripe->error_bitmap,
1083                       stripe->nr_sectors);
1084         if (!sctx->readonly && !bitmap_empty(&repaired, stripe->nr_sectors)) {
1085                 if (btrfs_is_zoned(fs_info)) {
1086                         btrfs_repair_one_zone(fs_info, sctx->stripes[0].bg->start);
1087                 } else {
1088                         scrub_write_sectors(sctx, stripe, repaired, false);
1089                         wait_scrub_stripe_io(stripe);
1090                 }
1091         }
1092
1093         scrub_stripe_report_errors(sctx, stripe);
1094         set_bit(SCRUB_STRIPE_FLAG_REPAIR_DONE, &stripe->state);
1095         wake_up(&stripe->repair_wait);
1096 }
1097
1098 static void scrub_read_endio(struct btrfs_bio *bbio)
1099 {
1100         struct scrub_stripe *stripe = bbio->private;
1101         struct bio_vec *bvec;
1102         int sector_nr = calc_sector_number(stripe, bio_first_bvec_all(&bbio->bio));
1103         int num_sectors;
1104         u32 bio_size = 0;
1105         int i;
1106
1107         ASSERT(sector_nr < stripe->nr_sectors);
1108         bio_for_each_bvec_all(bvec, &bbio->bio, i)
1109                 bio_size += bvec->bv_len;
1110         num_sectors = bio_size >> stripe->bg->fs_info->sectorsize_bits;
1111
1112         if (bbio->bio.bi_status) {
1113                 bitmap_set(&stripe->io_error_bitmap, sector_nr, num_sectors);
1114                 bitmap_set(&stripe->error_bitmap, sector_nr, num_sectors);
1115         } else {
1116                 bitmap_clear(&stripe->io_error_bitmap, sector_nr, num_sectors);
1117         }
1118         bio_put(&bbio->bio);
1119         if (atomic_dec_and_test(&stripe->pending_io)) {
1120                 wake_up(&stripe->io_wait);
1121                 INIT_WORK(&stripe->work, scrub_stripe_read_repair_worker);
1122                 queue_work(stripe->bg->fs_info->scrub_workers, &stripe->work);
1123         }
1124 }
1125
1126 static void scrub_write_endio(struct btrfs_bio *bbio)
1127 {
1128         struct scrub_stripe *stripe = bbio->private;
1129         struct btrfs_fs_info *fs_info = stripe->bg->fs_info;
1130         struct bio_vec *bvec;
1131         int sector_nr = calc_sector_number(stripe, bio_first_bvec_all(&bbio->bio));
1132         u32 bio_size = 0;
1133         int i;
1134
1135         bio_for_each_bvec_all(bvec, &bbio->bio, i)
1136                 bio_size += bvec->bv_len;
1137
1138         if (bbio->bio.bi_status) {
1139                 unsigned long flags;
1140
1141                 spin_lock_irqsave(&stripe->write_error_lock, flags);
1142                 bitmap_set(&stripe->write_error_bitmap, sector_nr,
1143                            bio_size >> fs_info->sectorsize_bits);
1144                 spin_unlock_irqrestore(&stripe->write_error_lock, flags);
1145         }
1146         bio_put(&bbio->bio);
1147
1148         if (atomic_dec_and_test(&stripe->pending_io))
1149                 wake_up(&stripe->io_wait);
1150 }
1151
1152 static void scrub_submit_write_bio(struct scrub_ctx *sctx,
1153                                    struct scrub_stripe *stripe,
1154                                    struct btrfs_bio *bbio, bool dev_replace)
1155 {
1156         struct btrfs_fs_info *fs_info = sctx->fs_info;
1157         u32 bio_len = bbio->bio.bi_iter.bi_size;
1158         u32 bio_off = (bbio->bio.bi_iter.bi_sector << SECTOR_SHIFT) -
1159                       stripe->logical;
1160
1161         fill_writer_pointer_gap(sctx, stripe->physical + bio_off);
1162         atomic_inc(&stripe->pending_io);
1163         btrfs_submit_repair_write(bbio, stripe->mirror_num, dev_replace);
1164         if (!btrfs_is_zoned(fs_info))
1165                 return;
1166         /*
1167          * For zoned writeback, queue depth must be 1, thus we must wait for
1168          * the write to finish before the next write.
1169          */
1170         wait_scrub_stripe_io(stripe);
1171
1172         /*
1173          * And also need to update the write pointer if write finished
1174          * successfully.
1175          */
1176         if (!test_bit(bio_off >> fs_info->sectorsize_bits,
1177                       &stripe->write_error_bitmap))
1178                 sctx->write_pointer += bio_len;
1179 }
1180
1181 /*
1182  * Submit the write bio(s) for the sectors specified by @write_bitmap.
1183  *
1184  * Here we utilize btrfs_submit_repair_write(), which has some extra benefits:
1185  *
1186  * - Only needs logical bytenr and mirror_num
1187  *   Just like the scrub read path
1188  *
1189  * - Would only result in writes to the specified mirror
1190  *   Unlike the regular writeback path, which would write back to all stripes
1191  *
1192  * - Handle dev-replace and read-repair writeback differently
1193  */
1194 static void scrub_write_sectors(struct scrub_ctx *sctx, struct scrub_stripe *stripe,
1195                                 unsigned long write_bitmap, bool dev_replace)
1196 {
1197         struct btrfs_fs_info *fs_info = stripe->bg->fs_info;
1198         struct btrfs_bio *bbio = NULL;
1199         int sector_nr;
1200
1201         for_each_set_bit(sector_nr, &write_bitmap, stripe->nr_sectors) {
1202                 struct page *page = scrub_stripe_get_page(stripe, sector_nr);
1203                 unsigned int pgoff = scrub_stripe_get_page_offset(stripe, sector_nr);
1204                 int ret;
1205
1206                 /* We should only writeback sectors covered by an extent. */
1207                 ASSERT(test_bit(sector_nr, &stripe->extent_sector_bitmap));
1208
1209                 /* Cannot merge with previous sector, submit the current one. */
1210                 if (bbio && sector_nr && !test_bit(sector_nr - 1, &write_bitmap)) {
1211                         scrub_submit_write_bio(sctx, stripe, bbio, dev_replace);
1212                         bbio = NULL;
1213                 }
1214                 if (!bbio) {
1215                         bbio = btrfs_bio_alloc(stripe->nr_sectors, REQ_OP_WRITE,
1216                                                fs_info, scrub_write_endio, stripe);
1217                         bbio->bio.bi_iter.bi_sector = (stripe->logical +
1218                                 (sector_nr << fs_info->sectorsize_bits)) >>
1219                                 SECTOR_SHIFT;
1220                 }
1221                 ret = bio_add_page(&bbio->bio, page, fs_info->sectorsize, pgoff);
1222                 ASSERT(ret == fs_info->sectorsize);
1223         }
1224         if (bbio)
1225                 scrub_submit_write_bio(sctx, stripe, bbio, dev_replace);
1226 }
1227
1228 /*
1229  * Throttling of IO submission, bandwidth-limit based, the timeslice is 1
1230  * second.  Limit can be set via /sys/fs/UUID/devinfo/devid/scrub_speed_max.
1231  */
1232 static void scrub_throttle_dev_io(struct scrub_ctx *sctx, struct btrfs_device *device,
1233                                   unsigned int bio_size)
1234 {
1235         const int time_slice = 1000;
1236         s64 delta;
1237         ktime_t now;
1238         u32 div;
1239         u64 bwlimit;
1240
1241         bwlimit = READ_ONCE(device->scrub_speed_max);
1242         if (bwlimit == 0)
1243                 return;
1244
1245         /*
1246          * Slice is divided into intervals when the IO is submitted, adjust by
1247          * bwlimit and maximum of 64 intervals.
1248          */
1249         div = max_t(u32, 1, (u32)(bwlimit / (16 * 1024 * 1024)));
1250         div = min_t(u32, 64, div);
1251
1252         /* Start new epoch, set deadline */
1253         now = ktime_get();
1254         if (sctx->throttle_deadline == 0) {
1255                 sctx->throttle_deadline = ktime_add_ms(now, time_slice / div);
1256                 sctx->throttle_sent = 0;
1257         }
1258
1259         /* Still in the time to send? */
1260         if (ktime_before(now, sctx->throttle_deadline)) {
1261                 /* If current bio is within the limit, send it */
1262                 sctx->throttle_sent += bio_size;
1263                 if (sctx->throttle_sent <= div_u64(bwlimit, div))
1264                         return;
1265
1266                 /* We're over the limit, sleep until the rest of the slice */
1267                 delta = ktime_ms_delta(sctx->throttle_deadline, now);
1268         } else {
1269                 /* New request after deadline, start new epoch */
1270                 delta = 0;
1271         }
1272
1273         if (delta) {
1274                 long timeout;
1275
1276                 timeout = div_u64(delta * HZ, 1000);
1277                 schedule_timeout_interruptible(timeout);
1278         }
1279
1280         /* Next call will start the deadline period */
1281         sctx->throttle_deadline = 0;
1282 }
1283
1284 /*
1285  * Given a physical address, this will calculate it's
1286  * logical offset. if this is a parity stripe, it will return
1287  * the most left data stripe's logical offset.
1288  *
1289  * return 0 if it is a data stripe, 1 means parity stripe.
1290  */
1291 static int get_raid56_logic_offset(u64 physical, int num,
1292                                    struct btrfs_chunk_map *map, u64 *offset,
1293                                    u64 *stripe_start)
1294 {
1295         int i;
1296         int j = 0;
1297         u64 last_offset;
1298         const int data_stripes = nr_data_stripes(map);
1299
1300         last_offset = (physical - map->stripes[num].physical) * data_stripes;
1301         if (stripe_start)
1302                 *stripe_start = last_offset;
1303
1304         *offset = last_offset;
1305         for (i = 0; i < data_stripes; i++) {
1306                 u32 stripe_nr;
1307                 u32 stripe_index;
1308                 u32 rot;
1309
1310                 *offset = last_offset + btrfs_stripe_nr_to_offset(i);
1311
1312                 stripe_nr = (u32)(*offset >> BTRFS_STRIPE_LEN_SHIFT) / data_stripes;
1313
1314                 /* Work out the disk rotation on this stripe-set */
1315                 rot = stripe_nr % map->num_stripes;
1316                 /* calculate which stripe this data locates */
1317                 rot += i;
1318                 stripe_index = rot % map->num_stripes;
1319                 if (stripe_index == num)
1320                         return 0;
1321                 if (stripe_index < num)
1322                         j++;
1323         }
1324         *offset = last_offset + btrfs_stripe_nr_to_offset(j);
1325         return 1;
1326 }
1327
1328 /*
1329  * Return 0 if the extent item range covers any byte of the range.
1330  * Return <0 if the extent item is before @search_start.
1331  * Return >0 if the extent item is after @start_start + @search_len.
1332  */
1333 static int compare_extent_item_range(struct btrfs_path *path,
1334                                      u64 search_start, u64 search_len)
1335 {
1336         struct btrfs_fs_info *fs_info = path->nodes[0]->fs_info;
1337         u64 len;
1338         struct btrfs_key key;
1339
1340         btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1341         ASSERT(key.type == BTRFS_EXTENT_ITEM_KEY ||
1342                key.type == BTRFS_METADATA_ITEM_KEY);
1343         if (key.type == BTRFS_METADATA_ITEM_KEY)
1344                 len = fs_info->nodesize;
1345         else
1346                 len = key.offset;
1347
1348         if (key.objectid + len <= search_start)
1349                 return -1;
1350         if (key.objectid >= search_start + search_len)
1351                 return 1;
1352         return 0;
1353 }
1354
1355 /*
1356  * Locate one extent item which covers any byte in range
1357  * [@search_start, @search_start + @search_length)
1358  *
1359  * If the path is not initialized, we will initialize the search by doing
1360  * a btrfs_search_slot().
1361  * If the path is already initialized, we will use the path as the initial
1362  * slot, to avoid duplicated btrfs_search_slot() calls.
1363  *
1364  * NOTE: If an extent item starts before @search_start, we will still
1365  * return the extent item. This is for data extent crossing stripe boundary.
1366  *
1367  * Return 0 if we found such extent item, and @path will point to the extent item.
1368  * Return >0 if no such extent item can be found, and @path will be released.
1369  * Return <0 if hit fatal error, and @path will be released.
1370  */
1371 static int find_first_extent_item(struct btrfs_root *extent_root,
1372                                   struct btrfs_path *path,
1373                                   u64 search_start, u64 search_len)
1374 {
1375         struct btrfs_fs_info *fs_info = extent_root->fs_info;
1376         struct btrfs_key key;
1377         int ret;
1378
1379         /* Continue using the existing path */
1380         if (path->nodes[0])
1381                 goto search_forward;
1382
1383         if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
1384                 key.type = BTRFS_METADATA_ITEM_KEY;
1385         else
1386                 key.type = BTRFS_EXTENT_ITEM_KEY;
1387         key.objectid = search_start;
1388         key.offset = (u64)-1;
1389
1390         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
1391         if (ret < 0)
1392                 return ret;
1393         if (ret == 0) {
1394                 /*
1395                  * Key with offset -1 found, there would have to exist an extent
1396                  * item with such offset, but this is out of the valid range.
1397                  */
1398                 btrfs_release_path(path);
1399                 return -EUCLEAN;
1400         }
1401
1402         /*
1403          * Here we intentionally pass 0 as @min_objectid, as there could be
1404          * an extent item starting before @search_start.
1405          */
1406         ret = btrfs_previous_extent_item(extent_root, path, 0);
1407         if (ret < 0)
1408                 return ret;
1409         /*
1410          * No matter whether we have found an extent item, the next loop will
1411          * properly do every check on the key.
1412          */
1413 search_forward:
1414         while (true) {
1415                 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1416                 if (key.objectid >= search_start + search_len)
1417                         break;
1418                 if (key.type != BTRFS_METADATA_ITEM_KEY &&
1419                     key.type != BTRFS_EXTENT_ITEM_KEY)
1420                         goto next;
1421
1422                 ret = compare_extent_item_range(path, search_start, search_len);
1423                 if (ret == 0)
1424                         return ret;
1425                 if (ret > 0)
1426                         break;
1427 next:
1428                 ret = btrfs_next_item(extent_root, path);
1429                 if (ret) {
1430                         /* Either no more items or a fatal error. */
1431                         btrfs_release_path(path);
1432                         return ret;
1433                 }
1434         }
1435         btrfs_release_path(path);
1436         return 1;
1437 }
1438
1439 static void get_extent_info(struct btrfs_path *path, u64 *extent_start_ret,
1440                             u64 *size_ret, u64 *flags_ret, u64 *generation_ret)
1441 {
1442         struct btrfs_key key;
1443         struct btrfs_extent_item *ei;
1444
1445         btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1446         ASSERT(key.type == BTRFS_METADATA_ITEM_KEY ||
1447                key.type == BTRFS_EXTENT_ITEM_KEY);
1448         *extent_start_ret = key.objectid;
1449         if (key.type == BTRFS_METADATA_ITEM_KEY)
1450                 *size_ret = path->nodes[0]->fs_info->nodesize;
1451         else
1452                 *size_ret = key.offset;
1453         ei = btrfs_item_ptr(path->nodes[0], path->slots[0], struct btrfs_extent_item);
1454         *flags_ret = btrfs_extent_flags(path->nodes[0], ei);
1455         *generation_ret = btrfs_extent_generation(path->nodes[0], ei);
1456 }
1457
1458 static int sync_write_pointer_for_zoned(struct scrub_ctx *sctx, u64 logical,
1459                                         u64 physical, u64 physical_end)
1460 {
1461         struct btrfs_fs_info *fs_info = sctx->fs_info;
1462         int ret = 0;
1463
1464         if (!btrfs_is_zoned(fs_info))
1465                 return 0;
1466
1467         mutex_lock(&sctx->wr_lock);
1468         if (sctx->write_pointer < physical_end) {
1469                 ret = btrfs_sync_zone_write_pointer(sctx->wr_tgtdev, logical,
1470                                                     physical,
1471                                                     sctx->write_pointer);
1472                 if (ret)
1473                         btrfs_err(fs_info,
1474                                   "zoned: failed to recover write pointer");
1475         }
1476         mutex_unlock(&sctx->wr_lock);
1477         btrfs_dev_clear_zone_empty(sctx->wr_tgtdev, physical);
1478
1479         return ret;
1480 }
1481
1482 static void fill_one_extent_info(struct btrfs_fs_info *fs_info,
1483                                  struct scrub_stripe *stripe,
1484                                  u64 extent_start, u64 extent_len,
1485                                  u64 extent_flags, u64 extent_gen)
1486 {
1487         for (u64 cur_logical = max(stripe->logical, extent_start);
1488              cur_logical < min(stripe->logical + BTRFS_STRIPE_LEN,
1489                                extent_start + extent_len);
1490              cur_logical += fs_info->sectorsize) {
1491                 const int nr_sector = (cur_logical - stripe->logical) >>
1492                                       fs_info->sectorsize_bits;
1493                 struct scrub_sector_verification *sector =
1494                                                 &stripe->sectors[nr_sector];
1495
1496                 set_bit(nr_sector, &stripe->extent_sector_bitmap);
1497                 if (extent_flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1498                         sector->is_metadata = true;
1499                         sector->generation = extent_gen;
1500                 }
1501         }
1502 }
1503
1504 static void scrub_stripe_reset_bitmaps(struct scrub_stripe *stripe)
1505 {
1506         stripe->extent_sector_bitmap = 0;
1507         stripe->init_error_bitmap = 0;
1508         stripe->init_nr_io_errors = 0;
1509         stripe->init_nr_csum_errors = 0;
1510         stripe->init_nr_meta_errors = 0;
1511         stripe->error_bitmap = 0;
1512         stripe->io_error_bitmap = 0;
1513         stripe->csum_error_bitmap = 0;
1514         stripe->meta_error_bitmap = 0;
1515 }
1516
1517 /*
1518  * Locate one stripe which has at least one extent in its range.
1519  *
1520  * Return 0 if found such stripe, and store its info into @stripe.
1521  * Return >0 if there is no such stripe in the specified range.
1522  * Return <0 for error.
1523  */
1524 static int scrub_find_fill_first_stripe(struct btrfs_block_group *bg,
1525                                         struct btrfs_path *extent_path,
1526                                         struct btrfs_path *csum_path,
1527                                         struct btrfs_device *dev, u64 physical,
1528                                         int mirror_num, u64 logical_start,
1529                                         u32 logical_len,
1530                                         struct scrub_stripe *stripe)
1531 {
1532         struct btrfs_fs_info *fs_info = bg->fs_info;
1533         struct btrfs_root *extent_root = btrfs_extent_root(fs_info, bg->start);
1534         struct btrfs_root *csum_root = btrfs_csum_root(fs_info, bg->start);
1535         const u64 logical_end = logical_start + logical_len;
1536         u64 cur_logical = logical_start;
1537         u64 stripe_end;
1538         u64 extent_start;
1539         u64 extent_len;
1540         u64 extent_flags;
1541         u64 extent_gen;
1542         int ret;
1543
1544         memset(stripe->sectors, 0, sizeof(struct scrub_sector_verification) *
1545                                    stripe->nr_sectors);
1546         scrub_stripe_reset_bitmaps(stripe);
1547
1548         /* The range must be inside the bg. */
1549         ASSERT(logical_start >= bg->start && logical_end <= bg->start + bg->length);
1550
1551         ret = find_first_extent_item(extent_root, extent_path, logical_start,
1552                                      logical_len);
1553         /* Either error or not found. */
1554         if (ret)
1555                 goto out;
1556         get_extent_info(extent_path, &extent_start, &extent_len, &extent_flags,
1557                         &extent_gen);
1558         if (extent_flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1559                 stripe->nr_meta_extents++;
1560         if (extent_flags & BTRFS_EXTENT_FLAG_DATA)
1561                 stripe->nr_data_extents++;
1562         cur_logical = max(extent_start, cur_logical);
1563
1564         /*
1565          * Round down to stripe boundary.
1566          *
1567          * The extra calculation against bg->start is to handle block groups
1568          * whose logical bytenr is not BTRFS_STRIPE_LEN aligned.
1569          */
1570         stripe->logical = round_down(cur_logical - bg->start, BTRFS_STRIPE_LEN) +
1571                           bg->start;
1572         stripe->physical = physical + stripe->logical - logical_start;
1573         stripe->dev = dev;
1574         stripe->bg = bg;
1575         stripe->mirror_num = mirror_num;
1576         stripe_end = stripe->logical + BTRFS_STRIPE_LEN - 1;
1577
1578         /* Fill the first extent info into stripe->sectors[] array. */
1579         fill_one_extent_info(fs_info, stripe, extent_start, extent_len,
1580                              extent_flags, extent_gen);
1581         cur_logical = extent_start + extent_len;
1582
1583         /* Fill the extent info for the remaining sectors. */
1584         while (cur_logical <= stripe_end) {
1585                 ret = find_first_extent_item(extent_root, extent_path, cur_logical,
1586                                              stripe_end - cur_logical + 1);
1587                 if (ret < 0)
1588                         goto out;
1589                 if (ret > 0) {
1590                         ret = 0;
1591                         break;
1592                 }
1593                 get_extent_info(extent_path, &extent_start, &extent_len,
1594                                 &extent_flags, &extent_gen);
1595                 if (extent_flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1596                         stripe->nr_meta_extents++;
1597                 if (extent_flags & BTRFS_EXTENT_FLAG_DATA)
1598                         stripe->nr_data_extents++;
1599                 fill_one_extent_info(fs_info, stripe, extent_start, extent_len,
1600                                      extent_flags, extent_gen);
1601                 cur_logical = extent_start + extent_len;
1602         }
1603
1604         /* Now fill the data csum. */
1605         if (bg->flags & BTRFS_BLOCK_GROUP_DATA) {
1606                 int sector_nr;
1607                 unsigned long csum_bitmap = 0;
1608
1609                 /* Csum space should have already been allocated. */
1610                 ASSERT(stripe->csums);
1611
1612                 /*
1613                  * Our csum bitmap should be large enough, as BTRFS_STRIPE_LEN
1614                  * should contain at most 16 sectors.
1615                  */
1616                 ASSERT(BITS_PER_LONG >= BTRFS_STRIPE_LEN >> fs_info->sectorsize_bits);
1617
1618                 ret = btrfs_lookup_csums_bitmap(csum_root, csum_path,
1619                                                 stripe->logical, stripe_end,
1620                                                 stripe->csums, &csum_bitmap);
1621                 if (ret < 0)
1622                         goto out;
1623                 if (ret > 0)
1624                         ret = 0;
1625
1626                 for_each_set_bit(sector_nr, &csum_bitmap, stripe->nr_sectors) {
1627                         stripe->sectors[sector_nr].csum = stripe->csums +
1628                                 sector_nr * fs_info->csum_size;
1629                 }
1630         }
1631         set_bit(SCRUB_STRIPE_FLAG_INITIALIZED, &stripe->state);
1632 out:
1633         return ret;
1634 }
1635
1636 static void scrub_reset_stripe(struct scrub_stripe *stripe)
1637 {
1638         scrub_stripe_reset_bitmaps(stripe);
1639
1640         stripe->nr_meta_extents = 0;
1641         stripe->nr_data_extents = 0;
1642         stripe->state = 0;
1643
1644         for (int i = 0; i < stripe->nr_sectors; i++) {
1645                 stripe->sectors[i].is_metadata = false;
1646                 stripe->sectors[i].csum = NULL;
1647                 stripe->sectors[i].generation = 0;
1648         }
1649 }
1650
1651 static void scrub_submit_extent_sector_read(struct scrub_ctx *sctx,
1652                                             struct scrub_stripe *stripe)
1653 {
1654         struct btrfs_fs_info *fs_info = stripe->bg->fs_info;
1655         struct btrfs_bio *bbio = NULL;
1656         unsigned int nr_sectors = min(BTRFS_STRIPE_LEN, stripe->bg->start +
1657                                       stripe->bg->length - stripe->logical) >>
1658                                   fs_info->sectorsize_bits;
1659         u64 stripe_len = BTRFS_STRIPE_LEN;
1660         int mirror = stripe->mirror_num;
1661         int i;
1662
1663         atomic_inc(&stripe->pending_io);
1664
1665         for_each_set_bit(i, &stripe->extent_sector_bitmap, stripe->nr_sectors) {
1666                 struct page *page = scrub_stripe_get_page(stripe, i);
1667                 unsigned int pgoff = scrub_stripe_get_page_offset(stripe, i);
1668
1669                 /* We're beyond the chunk boundary, no need to read anymore. */
1670                 if (i >= nr_sectors)
1671                         break;
1672
1673                 /* The current sector cannot be merged, submit the bio. */
1674                 if (bbio &&
1675                     ((i > 0 &&
1676                       !test_bit(i - 1, &stripe->extent_sector_bitmap)) ||
1677                      bbio->bio.bi_iter.bi_size >= stripe_len)) {
1678                         ASSERT(bbio->bio.bi_iter.bi_size);
1679                         atomic_inc(&stripe->pending_io);
1680                         btrfs_submit_bio(bbio, mirror);
1681                         bbio = NULL;
1682                 }
1683
1684                 if (!bbio) {
1685                         struct btrfs_io_stripe io_stripe = {};
1686                         struct btrfs_io_context *bioc = NULL;
1687                         const u64 logical = stripe->logical +
1688                                             (i << fs_info->sectorsize_bits);
1689                         int err;
1690
1691                         io_stripe.is_scrub = true;
1692                         stripe_len = (nr_sectors - i) << fs_info->sectorsize_bits;
1693                         /*
1694                          * For RST cases, we need to manually split the bbio to
1695                          * follow the RST boundary.
1696                          */
1697                         err = btrfs_map_block(fs_info, BTRFS_MAP_READ, logical,
1698                                               &stripe_len, &bioc, &io_stripe, &mirror);
1699                         btrfs_put_bioc(bioc);
1700                         if (err < 0) {
1701                                 set_bit(i, &stripe->io_error_bitmap);
1702                                 set_bit(i, &stripe->error_bitmap);
1703                                 continue;
1704                         }
1705
1706                         bbio = btrfs_bio_alloc(stripe->nr_sectors, REQ_OP_READ,
1707                                                fs_info, scrub_read_endio, stripe);
1708                         bbio->bio.bi_iter.bi_sector = logical >> SECTOR_SHIFT;
1709                 }
1710
1711                 __bio_add_page(&bbio->bio, page, fs_info->sectorsize, pgoff);
1712         }
1713
1714         if (bbio) {
1715                 ASSERT(bbio->bio.bi_iter.bi_size);
1716                 atomic_inc(&stripe->pending_io);
1717                 btrfs_submit_bio(bbio, mirror);
1718         }
1719
1720         if (atomic_dec_and_test(&stripe->pending_io)) {
1721                 wake_up(&stripe->io_wait);
1722                 INIT_WORK(&stripe->work, scrub_stripe_read_repair_worker);
1723                 queue_work(stripe->bg->fs_info->scrub_workers, &stripe->work);
1724         }
1725 }
1726
1727 static void scrub_submit_initial_read(struct scrub_ctx *sctx,
1728                                       struct scrub_stripe *stripe)
1729 {
1730         struct btrfs_fs_info *fs_info = sctx->fs_info;
1731         struct btrfs_bio *bbio;
1732         unsigned int nr_sectors = min(BTRFS_STRIPE_LEN, stripe->bg->start +
1733                                       stripe->bg->length - stripe->logical) >>
1734                                   fs_info->sectorsize_bits;
1735         int mirror = stripe->mirror_num;
1736
1737         ASSERT(stripe->bg);
1738         ASSERT(stripe->mirror_num > 0);
1739         ASSERT(test_bit(SCRUB_STRIPE_FLAG_INITIALIZED, &stripe->state));
1740
1741         if (btrfs_need_stripe_tree_update(fs_info, stripe->bg->flags)) {
1742                 scrub_submit_extent_sector_read(sctx, stripe);
1743                 return;
1744         }
1745
1746         bbio = btrfs_bio_alloc(SCRUB_STRIPE_PAGES, REQ_OP_READ, fs_info,
1747                                scrub_read_endio, stripe);
1748
1749         bbio->bio.bi_iter.bi_sector = stripe->logical >> SECTOR_SHIFT;
1750         /* Read the whole range inside the chunk boundary. */
1751         for (unsigned int cur = 0; cur < nr_sectors; cur++) {
1752                 struct page *page = scrub_stripe_get_page(stripe, cur);
1753                 unsigned int pgoff = scrub_stripe_get_page_offset(stripe, cur);
1754                 int ret;
1755
1756                 ret = bio_add_page(&bbio->bio, page, fs_info->sectorsize, pgoff);
1757                 /* We should have allocated enough bio vectors. */
1758                 ASSERT(ret == fs_info->sectorsize);
1759         }
1760         atomic_inc(&stripe->pending_io);
1761
1762         /*
1763          * For dev-replace, either user asks to avoid the source dev, or
1764          * the device is missing, we try the next mirror instead.
1765          */
1766         if (sctx->is_dev_replace &&
1767             (fs_info->dev_replace.cont_reading_from_srcdev_mode ==
1768              BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_AVOID ||
1769              !stripe->dev->bdev)) {
1770                 int num_copies = btrfs_num_copies(fs_info, stripe->bg->start,
1771                                                   stripe->bg->length);
1772
1773                 mirror = calc_next_mirror(mirror, num_copies);
1774         }
1775         btrfs_submit_bio(bbio, mirror);
1776 }
1777
1778 static bool stripe_has_metadata_error(struct scrub_stripe *stripe)
1779 {
1780         int i;
1781
1782         for_each_set_bit(i, &stripe->error_bitmap, stripe->nr_sectors) {
1783                 if (stripe->sectors[i].is_metadata) {
1784                         struct btrfs_fs_info *fs_info = stripe->bg->fs_info;
1785
1786                         btrfs_err(fs_info,
1787                         "stripe %llu has unrepaired metadata sector at %llu",
1788                                   stripe->logical,
1789                                   stripe->logical + (i << fs_info->sectorsize_bits));
1790                         return true;
1791                 }
1792         }
1793         return false;
1794 }
1795
1796 static void submit_initial_group_read(struct scrub_ctx *sctx,
1797                                       unsigned int first_slot,
1798                                       unsigned int nr_stripes)
1799 {
1800         struct blk_plug plug;
1801
1802         ASSERT(first_slot < SCRUB_TOTAL_STRIPES);
1803         ASSERT(first_slot + nr_stripes <= SCRUB_TOTAL_STRIPES);
1804
1805         scrub_throttle_dev_io(sctx, sctx->stripes[0].dev,
1806                               btrfs_stripe_nr_to_offset(nr_stripes));
1807         blk_start_plug(&plug);
1808         for (int i = 0; i < nr_stripes; i++) {
1809                 struct scrub_stripe *stripe = &sctx->stripes[first_slot + i];
1810
1811                 /* Those stripes should be initialized. */
1812                 ASSERT(test_bit(SCRUB_STRIPE_FLAG_INITIALIZED, &stripe->state));
1813                 scrub_submit_initial_read(sctx, stripe);
1814         }
1815         blk_finish_plug(&plug);
1816 }
1817
1818 static int flush_scrub_stripes(struct scrub_ctx *sctx)
1819 {
1820         struct btrfs_fs_info *fs_info = sctx->fs_info;
1821         struct scrub_stripe *stripe;
1822         const int nr_stripes = sctx->cur_stripe;
1823         int ret = 0;
1824
1825         if (!nr_stripes)
1826                 return 0;
1827
1828         ASSERT(test_bit(SCRUB_STRIPE_FLAG_INITIALIZED, &sctx->stripes[0].state));
1829
1830         /* Submit the stripes which are populated but not submitted. */
1831         if (nr_stripes % SCRUB_STRIPES_PER_GROUP) {
1832                 const int first_slot = round_down(nr_stripes, SCRUB_STRIPES_PER_GROUP);
1833
1834                 submit_initial_group_read(sctx, first_slot, nr_stripes - first_slot);
1835         }
1836
1837         for (int i = 0; i < nr_stripes; i++) {
1838                 stripe = &sctx->stripes[i];
1839
1840                 wait_event(stripe->repair_wait,
1841                            test_bit(SCRUB_STRIPE_FLAG_REPAIR_DONE, &stripe->state));
1842         }
1843
1844         /* Submit for dev-replace. */
1845         if (sctx->is_dev_replace) {
1846                 /*
1847                  * For dev-replace, if we know there is something wrong with
1848                  * metadata, we should immediately abort.
1849                  */
1850                 for (int i = 0; i < nr_stripes; i++) {
1851                         if (stripe_has_metadata_error(&sctx->stripes[i])) {
1852                                 ret = -EIO;
1853                                 goto out;
1854                         }
1855                 }
1856                 for (int i = 0; i < nr_stripes; i++) {
1857                         unsigned long good;
1858
1859                         stripe = &sctx->stripes[i];
1860
1861                         ASSERT(stripe->dev == fs_info->dev_replace.srcdev);
1862
1863                         bitmap_andnot(&good, &stripe->extent_sector_bitmap,
1864                                       &stripe->error_bitmap, stripe->nr_sectors);
1865                         scrub_write_sectors(sctx, stripe, good, true);
1866                 }
1867         }
1868
1869         /* Wait for the above writebacks to finish. */
1870         for (int i = 0; i < nr_stripes; i++) {
1871                 stripe = &sctx->stripes[i];
1872
1873                 wait_scrub_stripe_io(stripe);
1874                 scrub_reset_stripe(stripe);
1875         }
1876 out:
1877         sctx->cur_stripe = 0;
1878         return ret;
1879 }
1880
1881 static void raid56_scrub_wait_endio(struct bio *bio)
1882 {
1883         complete(bio->bi_private);
1884 }
1885
1886 static int queue_scrub_stripe(struct scrub_ctx *sctx, struct btrfs_block_group *bg,
1887                               struct btrfs_device *dev, int mirror_num,
1888                               u64 logical, u32 length, u64 physical,
1889                               u64 *found_logical_ret)
1890 {
1891         struct scrub_stripe *stripe;
1892         int ret;
1893
1894         /*
1895          * There should always be one slot left, as caller filling the last
1896          * slot should flush them all.
1897          */
1898         ASSERT(sctx->cur_stripe < SCRUB_TOTAL_STRIPES);
1899
1900         /* @found_logical_ret must be specified. */
1901         ASSERT(found_logical_ret);
1902
1903         stripe = &sctx->stripes[sctx->cur_stripe];
1904         scrub_reset_stripe(stripe);
1905         ret = scrub_find_fill_first_stripe(bg, &sctx->extent_path,
1906                                            &sctx->csum_path, dev, physical,
1907                                            mirror_num, logical, length, stripe);
1908         /* Either >0 as no more extents or <0 for error. */
1909         if (ret)
1910                 return ret;
1911         *found_logical_ret = stripe->logical;
1912         sctx->cur_stripe++;
1913
1914         /* We filled one group, submit it. */
1915         if (sctx->cur_stripe % SCRUB_STRIPES_PER_GROUP == 0) {
1916                 const int first_slot = sctx->cur_stripe - SCRUB_STRIPES_PER_GROUP;
1917
1918                 submit_initial_group_read(sctx, first_slot, SCRUB_STRIPES_PER_GROUP);
1919         }
1920
1921         /* Last slot used, flush them all. */
1922         if (sctx->cur_stripe == SCRUB_TOTAL_STRIPES)
1923                 return flush_scrub_stripes(sctx);
1924         return 0;
1925 }
1926
1927 static int scrub_raid56_parity_stripe(struct scrub_ctx *sctx,
1928                                       struct btrfs_device *scrub_dev,
1929                                       struct btrfs_block_group *bg,
1930                                       struct btrfs_chunk_map *map,
1931                                       u64 full_stripe_start)
1932 {
1933         DECLARE_COMPLETION_ONSTACK(io_done);
1934         struct btrfs_fs_info *fs_info = sctx->fs_info;
1935         struct btrfs_raid_bio *rbio;
1936         struct btrfs_io_context *bioc = NULL;
1937         struct btrfs_path extent_path = { 0 };
1938         struct btrfs_path csum_path = { 0 };
1939         struct bio *bio;
1940         struct scrub_stripe *stripe;
1941         bool all_empty = true;
1942         const int data_stripes = nr_data_stripes(map);
1943         unsigned long extent_bitmap = 0;
1944         u64 length = btrfs_stripe_nr_to_offset(data_stripes);
1945         int ret;
1946
1947         ASSERT(sctx->raid56_data_stripes);
1948
1949         /*
1950          * For data stripe search, we cannot re-use the same extent/csum paths,
1951          * as the data stripe bytenr may be smaller than previous extent.  Thus
1952          * we have to use our own extent/csum paths.
1953          */
1954         extent_path.search_commit_root = 1;
1955         extent_path.skip_locking = 1;
1956         csum_path.search_commit_root = 1;
1957         csum_path.skip_locking = 1;
1958
1959         for (int i = 0; i < data_stripes; i++) {
1960                 int stripe_index;
1961                 int rot;
1962                 u64 physical;
1963
1964                 stripe = &sctx->raid56_data_stripes[i];
1965                 rot = div_u64(full_stripe_start - bg->start,
1966                               data_stripes) >> BTRFS_STRIPE_LEN_SHIFT;
1967                 stripe_index = (i + rot) % map->num_stripes;
1968                 physical = map->stripes[stripe_index].physical +
1969                            btrfs_stripe_nr_to_offset(rot);
1970
1971                 scrub_reset_stripe(stripe);
1972                 set_bit(SCRUB_STRIPE_FLAG_NO_REPORT, &stripe->state);
1973                 ret = scrub_find_fill_first_stripe(bg, &extent_path, &csum_path,
1974                                 map->stripes[stripe_index].dev, physical, 1,
1975                                 full_stripe_start + btrfs_stripe_nr_to_offset(i),
1976                                 BTRFS_STRIPE_LEN, stripe);
1977                 if (ret < 0)
1978                         goto out;
1979                 /*
1980                  * No extent in this data stripe, need to manually mark them
1981                  * initialized to make later read submission happy.
1982                  */
1983                 if (ret > 0) {
1984                         stripe->logical = full_stripe_start +
1985                                           btrfs_stripe_nr_to_offset(i);
1986                         stripe->dev = map->stripes[stripe_index].dev;
1987                         stripe->mirror_num = 1;
1988                         set_bit(SCRUB_STRIPE_FLAG_INITIALIZED, &stripe->state);
1989                 }
1990         }
1991
1992         /* Check if all data stripes are empty. */
1993         for (int i = 0; i < data_stripes; i++) {
1994                 stripe = &sctx->raid56_data_stripes[i];
1995                 if (!bitmap_empty(&stripe->extent_sector_bitmap, stripe->nr_sectors)) {
1996                         all_empty = false;
1997                         break;
1998                 }
1999         }
2000         if (all_empty) {
2001                 ret = 0;
2002                 goto out;
2003         }
2004
2005         for (int i = 0; i < data_stripes; i++) {
2006                 stripe = &sctx->raid56_data_stripes[i];
2007                 scrub_submit_initial_read(sctx, stripe);
2008         }
2009         for (int i = 0; i < data_stripes; i++) {
2010                 stripe = &sctx->raid56_data_stripes[i];
2011
2012                 wait_event(stripe->repair_wait,
2013                            test_bit(SCRUB_STRIPE_FLAG_REPAIR_DONE, &stripe->state));
2014         }
2015         /* For now, no zoned support for RAID56. */
2016         ASSERT(!btrfs_is_zoned(sctx->fs_info));
2017
2018         /*
2019          * Now all data stripes are properly verified. Check if we have any
2020          * unrepaired, if so abort immediately or we could further corrupt the
2021          * P/Q stripes.
2022          *
2023          * During the loop, also populate extent_bitmap.
2024          */
2025         for (int i = 0; i < data_stripes; i++) {
2026                 unsigned long error;
2027
2028                 stripe = &sctx->raid56_data_stripes[i];
2029
2030                 /*
2031                  * We should only check the errors where there is an extent.
2032                  * As we may hit an empty data stripe while it's missing.
2033                  */
2034                 bitmap_and(&error, &stripe->error_bitmap,
2035                            &stripe->extent_sector_bitmap, stripe->nr_sectors);
2036                 if (!bitmap_empty(&error, stripe->nr_sectors)) {
2037                         btrfs_err(fs_info,
2038 "unrepaired sectors detected, full stripe %llu data stripe %u errors %*pbl",
2039                                   full_stripe_start, i, stripe->nr_sectors,
2040                                   &error);
2041                         ret = -EIO;
2042                         goto out;
2043                 }
2044                 bitmap_or(&extent_bitmap, &extent_bitmap,
2045                           &stripe->extent_sector_bitmap, stripe->nr_sectors);
2046         }
2047
2048         /* Now we can check and regenerate the P/Q stripe. */
2049         bio = bio_alloc(NULL, 1, REQ_OP_READ, GFP_NOFS);
2050         bio->bi_iter.bi_sector = full_stripe_start >> SECTOR_SHIFT;
2051         bio->bi_private = &io_done;
2052         bio->bi_end_io = raid56_scrub_wait_endio;
2053
2054         btrfs_bio_counter_inc_blocked(fs_info);
2055         ret = btrfs_map_block(fs_info, BTRFS_MAP_WRITE, full_stripe_start,
2056                               &length, &bioc, NULL, NULL);
2057         if (ret < 0) {
2058                 btrfs_put_bioc(bioc);
2059                 btrfs_bio_counter_dec(fs_info);
2060                 goto out;
2061         }
2062         rbio = raid56_parity_alloc_scrub_rbio(bio, bioc, scrub_dev, &extent_bitmap,
2063                                 BTRFS_STRIPE_LEN >> fs_info->sectorsize_bits);
2064         btrfs_put_bioc(bioc);
2065         if (!rbio) {
2066                 ret = -ENOMEM;
2067                 btrfs_bio_counter_dec(fs_info);
2068                 goto out;
2069         }
2070         /* Use the recovered stripes as cache to avoid read them from disk again. */
2071         for (int i = 0; i < data_stripes; i++) {
2072                 stripe = &sctx->raid56_data_stripes[i];
2073
2074                 raid56_parity_cache_data_pages(rbio, stripe->pages,
2075                                 full_stripe_start + (i << BTRFS_STRIPE_LEN_SHIFT));
2076         }
2077         raid56_parity_submit_scrub_rbio(rbio);
2078         wait_for_completion_io(&io_done);
2079         ret = blk_status_to_errno(bio->bi_status);
2080         bio_put(bio);
2081         btrfs_bio_counter_dec(fs_info);
2082
2083         btrfs_release_path(&extent_path);
2084         btrfs_release_path(&csum_path);
2085 out:
2086         return ret;
2087 }
2088
2089 /*
2090  * Scrub one range which can only has simple mirror based profile.
2091  * (Including all range in SINGLE/DUP/RAID1/RAID1C*, and each stripe in
2092  *  RAID0/RAID10).
2093  *
2094  * Since we may need to handle a subset of block group, we need @logical_start
2095  * and @logical_length parameter.
2096  */
2097 static int scrub_simple_mirror(struct scrub_ctx *sctx,
2098                                struct btrfs_block_group *bg,
2099                                struct btrfs_chunk_map *map,
2100                                u64 logical_start, u64 logical_length,
2101                                struct btrfs_device *device,
2102                                u64 physical, int mirror_num)
2103 {
2104         struct btrfs_fs_info *fs_info = sctx->fs_info;
2105         const u64 logical_end = logical_start + logical_length;
2106         u64 cur_logical = logical_start;
2107         int ret = 0;
2108
2109         /* The range must be inside the bg */
2110         ASSERT(logical_start >= bg->start && logical_end <= bg->start + bg->length);
2111
2112         /* Go through each extent items inside the logical range */
2113         while (cur_logical < logical_end) {
2114                 u64 found_logical = U64_MAX;
2115                 u64 cur_physical = physical + cur_logical - logical_start;
2116
2117                 /* Canceled? */
2118                 if (atomic_read(&fs_info->scrub_cancel_req) ||
2119                     atomic_read(&sctx->cancel_req)) {
2120                         ret = -ECANCELED;
2121                         break;
2122                 }
2123                 /* Paused? */
2124                 if (atomic_read(&fs_info->scrub_pause_req)) {
2125                         /* Push queued extents */
2126                         scrub_blocked_if_needed(fs_info);
2127                 }
2128                 /* Block group removed? */
2129                 spin_lock(&bg->lock);
2130                 if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &bg->runtime_flags)) {
2131                         spin_unlock(&bg->lock);
2132                         ret = 0;
2133                         break;
2134                 }
2135                 spin_unlock(&bg->lock);
2136
2137                 ret = queue_scrub_stripe(sctx, bg, device, mirror_num,
2138                                          cur_logical, logical_end - cur_logical,
2139                                          cur_physical, &found_logical);
2140                 if (ret > 0) {
2141                         /* No more extent, just update the accounting */
2142                         sctx->stat.last_physical = physical + logical_length;
2143                         ret = 0;
2144                         break;
2145                 }
2146                 if (ret < 0)
2147                         break;
2148
2149                 /* queue_scrub_stripe() returned 0, @found_logical must be updated. */
2150                 ASSERT(found_logical != U64_MAX);
2151                 cur_logical = found_logical + BTRFS_STRIPE_LEN;
2152
2153                 /* Don't hold CPU for too long time */
2154                 cond_resched();
2155         }
2156         return ret;
2157 }
2158
2159 /* Calculate the full stripe length for simple stripe based profiles */
2160 static u64 simple_stripe_full_stripe_len(const struct btrfs_chunk_map *map)
2161 {
2162         ASSERT(map->type & (BTRFS_BLOCK_GROUP_RAID0 |
2163                             BTRFS_BLOCK_GROUP_RAID10));
2164
2165         return btrfs_stripe_nr_to_offset(map->num_stripes / map->sub_stripes);
2166 }
2167
2168 /* Get the logical bytenr for the stripe */
2169 static u64 simple_stripe_get_logical(struct btrfs_chunk_map *map,
2170                                      struct btrfs_block_group *bg,
2171                                      int stripe_index)
2172 {
2173         ASSERT(map->type & (BTRFS_BLOCK_GROUP_RAID0 |
2174                             BTRFS_BLOCK_GROUP_RAID10));
2175         ASSERT(stripe_index < map->num_stripes);
2176
2177         /*
2178          * (stripe_index / sub_stripes) gives how many data stripes we need to
2179          * skip.
2180          */
2181         return btrfs_stripe_nr_to_offset(stripe_index / map->sub_stripes) +
2182                bg->start;
2183 }
2184
2185 /* Get the mirror number for the stripe */
2186 static int simple_stripe_mirror_num(struct btrfs_chunk_map *map, int stripe_index)
2187 {
2188         ASSERT(map->type & (BTRFS_BLOCK_GROUP_RAID0 |
2189                             BTRFS_BLOCK_GROUP_RAID10));
2190         ASSERT(stripe_index < map->num_stripes);
2191
2192         /* For RAID0, it's fixed to 1, for RAID10 it's 0,1,0,1... */
2193         return stripe_index % map->sub_stripes + 1;
2194 }
2195
2196 static int scrub_simple_stripe(struct scrub_ctx *sctx,
2197                                struct btrfs_block_group *bg,
2198                                struct btrfs_chunk_map *map,
2199                                struct btrfs_device *device,
2200                                int stripe_index)
2201 {
2202         const u64 logical_increment = simple_stripe_full_stripe_len(map);
2203         const u64 orig_logical = simple_stripe_get_logical(map, bg, stripe_index);
2204         const u64 orig_physical = map->stripes[stripe_index].physical;
2205         const int mirror_num = simple_stripe_mirror_num(map, stripe_index);
2206         u64 cur_logical = orig_logical;
2207         u64 cur_physical = orig_physical;
2208         int ret = 0;
2209
2210         while (cur_logical < bg->start + bg->length) {
2211                 /*
2212                  * Inside each stripe, RAID0 is just SINGLE, and RAID10 is
2213                  * just RAID1, so we can reuse scrub_simple_mirror() to scrub
2214                  * this stripe.
2215                  */
2216                 ret = scrub_simple_mirror(sctx, bg, map, cur_logical,
2217                                           BTRFS_STRIPE_LEN, device, cur_physical,
2218                                           mirror_num);
2219                 if (ret)
2220                         return ret;
2221                 /* Skip to next stripe which belongs to the target device */
2222                 cur_logical += logical_increment;
2223                 /* For physical offset, we just go to next stripe */
2224                 cur_physical += BTRFS_STRIPE_LEN;
2225         }
2226         return ret;
2227 }
2228
2229 static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
2230                                            struct btrfs_block_group *bg,
2231                                            struct btrfs_chunk_map *map,
2232                                            struct btrfs_device *scrub_dev,
2233                                            int stripe_index)
2234 {
2235         struct btrfs_fs_info *fs_info = sctx->fs_info;
2236         const u64 profile = map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK;
2237         const u64 chunk_logical = bg->start;
2238         int ret;
2239         int ret2;
2240         u64 physical = map->stripes[stripe_index].physical;
2241         const u64 dev_stripe_len = btrfs_calc_stripe_length(map);
2242         const u64 physical_end = physical + dev_stripe_len;
2243         u64 logical;
2244         u64 logic_end;
2245         /* The logical increment after finishing one stripe */
2246         u64 increment;
2247         /* Offset inside the chunk */
2248         u64 offset;
2249         u64 stripe_logical;
2250         int stop_loop = 0;
2251
2252         /* Extent_path should be released by now. */
2253         ASSERT(sctx->extent_path.nodes[0] == NULL);
2254
2255         scrub_blocked_if_needed(fs_info);
2256
2257         if (sctx->is_dev_replace &&
2258             btrfs_dev_is_sequential(sctx->wr_tgtdev, physical)) {
2259                 mutex_lock(&sctx->wr_lock);
2260                 sctx->write_pointer = physical;
2261                 mutex_unlock(&sctx->wr_lock);
2262         }
2263
2264         /* Prepare the extra data stripes used by RAID56. */
2265         if (profile & BTRFS_BLOCK_GROUP_RAID56_MASK) {
2266                 ASSERT(sctx->raid56_data_stripes == NULL);
2267
2268                 sctx->raid56_data_stripes = kcalloc(nr_data_stripes(map),
2269                                                     sizeof(struct scrub_stripe),
2270                                                     GFP_KERNEL);
2271                 if (!sctx->raid56_data_stripes) {
2272                         ret = -ENOMEM;
2273                         goto out;
2274                 }
2275                 for (int i = 0; i < nr_data_stripes(map); i++) {
2276                         ret = init_scrub_stripe(fs_info,
2277                                                 &sctx->raid56_data_stripes[i]);
2278                         if (ret < 0)
2279                                 goto out;
2280                         sctx->raid56_data_stripes[i].bg = bg;
2281                         sctx->raid56_data_stripes[i].sctx = sctx;
2282                 }
2283         }
2284         /*
2285          * There used to be a big double loop to handle all profiles using the
2286          * same routine, which grows larger and more gross over time.
2287          *
2288          * So here we handle each profile differently, so simpler profiles
2289          * have simpler scrubbing function.
2290          */
2291         if (!(profile & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10 |
2292                          BTRFS_BLOCK_GROUP_RAID56_MASK))) {
2293                 /*
2294                  * Above check rules out all complex profile, the remaining
2295                  * profiles are SINGLE|DUP|RAID1|RAID1C*, which is simple
2296                  * mirrored duplication without stripe.
2297                  *
2298                  * Only @physical and @mirror_num needs to calculated using
2299                  * @stripe_index.
2300                  */
2301                 ret = scrub_simple_mirror(sctx, bg, map, bg->start, bg->length,
2302                                 scrub_dev, map->stripes[stripe_index].physical,
2303                                 stripe_index + 1);
2304                 offset = 0;
2305                 goto out;
2306         }
2307         if (profile & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
2308                 ret = scrub_simple_stripe(sctx, bg, map, scrub_dev, stripe_index);
2309                 offset = btrfs_stripe_nr_to_offset(stripe_index / map->sub_stripes);
2310                 goto out;
2311         }
2312
2313         /* Only RAID56 goes through the old code */
2314         ASSERT(map->type & BTRFS_BLOCK_GROUP_RAID56_MASK);
2315         ret = 0;
2316
2317         /* Calculate the logical end of the stripe */
2318         get_raid56_logic_offset(physical_end, stripe_index,
2319                                 map, &logic_end, NULL);
2320         logic_end += chunk_logical;
2321
2322         /* Initialize @offset in case we need to go to out: label */
2323         get_raid56_logic_offset(physical, stripe_index, map, &offset, NULL);
2324         increment = btrfs_stripe_nr_to_offset(nr_data_stripes(map));
2325
2326         /*
2327          * Due to the rotation, for RAID56 it's better to iterate each stripe
2328          * using their physical offset.
2329          */
2330         while (physical < physical_end) {
2331                 ret = get_raid56_logic_offset(physical, stripe_index, map,
2332                                               &logical, &stripe_logical);
2333                 logical += chunk_logical;
2334                 if (ret) {
2335                         /* it is parity strip */
2336                         stripe_logical += chunk_logical;
2337                         ret = scrub_raid56_parity_stripe(sctx, scrub_dev, bg,
2338                                                          map, stripe_logical);
2339                         if (ret)
2340                                 goto out;
2341                         goto next;
2342                 }
2343
2344                 /*
2345                  * Now we're at a data stripe, scrub each extents in the range.
2346                  *
2347                  * At this stage, if we ignore the repair part, inside each data
2348                  * stripe it is no different than SINGLE profile.
2349                  * We can reuse scrub_simple_mirror() here, as the repair part
2350                  * is still based on @mirror_num.
2351                  */
2352                 ret = scrub_simple_mirror(sctx, bg, map, logical, BTRFS_STRIPE_LEN,
2353                                           scrub_dev, physical, 1);
2354                 if (ret < 0)
2355                         goto out;
2356 next:
2357                 logical += increment;
2358                 physical += BTRFS_STRIPE_LEN;
2359                 spin_lock(&sctx->stat_lock);
2360                 if (stop_loop)
2361                         sctx->stat.last_physical =
2362                                 map->stripes[stripe_index].physical + dev_stripe_len;
2363                 else
2364                         sctx->stat.last_physical = physical;
2365                 spin_unlock(&sctx->stat_lock);
2366                 if (stop_loop)
2367                         break;
2368         }
2369 out:
2370         ret2 = flush_scrub_stripes(sctx);
2371         if (!ret)
2372                 ret = ret2;
2373         btrfs_release_path(&sctx->extent_path);
2374         btrfs_release_path(&sctx->csum_path);
2375
2376         if (sctx->raid56_data_stripes) {
2377                 for (int i = 0; i < nr_data_stripes(map); i++)
2378                         release_scrub_stripe(&sctx->raid56_data_stripes[i]);
2379                 kfree(sctx->raid56_data_stripes);
2380                 sctx->raid56_data_stripes = NULL;
2381         }
2382
2383         if (sctx->is_dev_replace && ret >= 0) {
2384                 int ret2;
2385
2386                 ret2 = sync_write_pointer_for_zoned(sctx,
2387                                 chunk_logical + offset,
2388                                 map->stripes[stripe_index].physical,
2389                                 physical_end);
2390                 if (ret2)
2391                         ret = ret2;
2392         }
2393
2394         return ret < 0 ? ret : 0;
2395 }
2396
2397 static noinline_for_stack int scrub_chunk(struct scrub_ctx *sctx,
2398                                           struct btrfs_block_group *bg,
2399                                           struct btrfs_device *scrub_dev,
2400                                           u64 dev_offset,
2401                                           u64 dev_extent_len)
2402 {
2403         struct btrfs_fs_info *fs_info = sctx->fs_info;
2404         struct btrfs_chunk_map *map;
2405         int i;
2406         int ret = 0;
2407
2408         map = btrfs_find_chunk_map(fs_info, bg->start, bg->length);
2409         if (!map) {
2410                 /*
2411                  * Might have been an unused block group deleted by the cleaner
2412                  * kthread or relocation.
2413                  */
2414                 spin_lock(&bg->lock);
2415                 if (!test_bit(BLOCK_GROUP_FLAG_REMOVED, &bg->runtime_flags))
2416                         ret = -EINVAL;
2417                 spin_unlock(&bg->lock);
2418
2419                 return ret;
2420         }
2421         if (map->start != bg->start)
2422                 goto out;
2423         if (map->chunk_len < dev_extent_len)
2424                 goto out;
2425
2426         for (i = 0; i < map->num_stripes; ++i) {
2427                 if (map->stripes[i].dev->bdev == scrub_dev->bdev &&
2428                     map->stripes[i].physical == dev_offset) {
2429                         ret = scrub_stripe(sctx, bg, map, scrub_dev, i);
2430                         if (ret)
2431                                 goto out;
2432                 }
2433         }
2434 out:
2435         btrfs_free_chunk_map(map);
2436
2437         return ret;
2438 }
2439
2440 static int finish_extent_writes_for_zoned(struct btrfs_root *root,
2441                                           struct btrfs_block_group *cache)
2442 {
2443         struct btrfs_fs_info *fs_info = cache->fs_info;
2444         struct btrfs_trans_handle *trans;
2445
2446         if (!btrfs_is_zoned(fs_info))
2447                 return 0;
2448
2449         btrfs_wait_block_group_reservations(cache);
2450         btrfs_wait_nocow_writers(cache);
2451         btrfs_wait_ordered_roots(fs_info, U64_MAX, cache->start, cache->length);
2452
2453         trans = btrfs_join_transaction(root);
2454         if (IS_ERR(trans))
2455                 return PTR_ERR(trans);
2456         return btrfs_commit_transaction(trans);
2457 }
2458
2459 static noinline_for_stack
2460 int scrub_enumerate_chunks(struct scrub_ctx *sctx,
2461                            struct btrfs_device *scrub_dev, u64 start, u64 end)
2462 {
2463         struct btrfs_dev_extent *dev_extent = NULL;
2464         struct btrfs_path *path;
2465         struct btrfs_fs_info *fs_info = sctx->fs_info;
2466         struct btrfs_root *root = fs_info->dev_root;
2467         u64 chunk_offset;
2468         int ret = 0;
2469         int ro_set;
2470         int slot;
2471         struct extent_buffer *l;
2472         struct btrfs_key key;
2473         struct btrfs_key found_key;
2474         struct btrfs_block_group *cache;
2475         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
2476
2477         path = btrfs_alloc_path();
2478         if (!path)
2479                 return -ENOMEM;
2480
2481         path->reada = READA_FORWARD;
2482         path->search_commit_root = 1;
2483         path->skip_locking = 1;
2484
2485         key.objectid = scrub_dev->devid;
2486         key.offset = 0ull;
2487         key.type = BTRFS_DEV_EXTENT_KEY;
2488
2489         while (1) {
2490                 u64 dev_extent_len;
2491
2492                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2493                 if (ret < 0)
2494                         break;
2495                 if (ret > 0) {
2496                         if (path->slots[0] >=
2497                             btrfs_header_nritems(path->nodes[0])) {
2498                                 ret = btrfs_next_leaf(root, path);
2499                                 if (ret < 0)
2500                                         break;
2501                                 if (ret > 0) {
2502                                         ret = 0;
2503                                         break;
2504                                 }
2505                         } else {
2506                                 ret = 0;
2507                         }
2508                 }
2509
2510                 l = path->nodes[0];
2511                 slot = path->slots[0];
2512
2513                 btrfs_item_key_to_cpu(l, &found_key, slot);
2514
2515                 if (found_key.objectid != scrub_dev->devid)
2516                         break;
2517
2518                 if (found_key.type != BTRFS_DEV_EXTENT_KEY)
2519                         break;
2520
2521                 if (found_key.offset >= end)
2522                         break;
2523
2524                 if (found_key.offset < key.offset)
2525                         break;
2526
2527                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
2528                 dev_extent_len = btrfs_dev_extent_length(l, dev_extent);
2529
2530                 if (found_key.offset + dev_extent_len <= start)
2531                         goto skip;
2532
2533                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
2534
2535                 /*
2536                  * get a reference on the corresponding block group to prevent
2537                  * the chunk from going away while we scrub it
2538                  */
2539                 cache = btrfs_lookup_block_group(fs_info, chunk_offset);
2540
2541                 /* some chunks are removed but not committed to disk yet,
2542                  * continue scrubbing */
2543                 if (!cache)
2544                         goto skip;
2545
2546                 ASSERT(cache->start <= chunk_offset);
2547                 /*
2548                  * We are using the commit root to search for device extents, so
2549                  * that means we could have found a device extent item from a
2550                  * block group that was deleted in the current transaction. The
2551                  * logical start offset of the deleted block group, stored at
2552                  * @chunk_offset, might be part of the logical address range of
2553                  * a new block group (which uses different physical extents).
2554                  * In this case btrfs_lookup_block_group() has returned the new
2555                  * block group, and its start address is less than @chunk_offset.
2556                  *
2557                  * We skip such new block groups, because it's pointless to
2558                  * process them, as we won't find their extents because we search
2559                  * for them using the commit root of the extent tree. For a device
2560                  * replace it's also fine to skip it, we won't miss copying them
2561                  * to the target device because we have the write duplication
2562                  * setup through the regular write path (by btrfs_map_block()),
2563                  * and we have committed a transaction when we started the device
2564                  * replace, right after setting up the device replace state.
2565                  */
2566                 if (cache->start < chunk_offset) {
2567                         btrfs_put_block_group(cache);
2568                         goto skip;
2569                 }
2570
2571                 if (sctx->is_dev_replace && btrfs_is_zoned(fs_info)) {
2572                         if (!test_bit(BLOCK_GROUP_FLAG_TO_COPY, &cache->runtime_flags)) {
2573                                 btrfs_put_block_group(cache);
2574                                 goto skip;
2575                         }
2576                 }
2577
2578                 /*
2579                  * Make sure that while we are scrubbing the corresponding block
2580                  * group doesn't get its logical address and its device extents
2581                  * reused for another block group, which can possibly be of a
2582                  * different type and different profile. We do this to prevent
2583                  * false error detections and crashes due to bogus attempts to
2584                  * repair extents.
2585                  */
2586                 spin_lock(&cache->lock);
2587                 if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &cache->runtime_flags)) {
2588                         spin_unlock(&cache->lock);
2589                         btrfs_put_block_group(cache);
2590                         goto skip;
2591                 }
2592                 btrfs_freeze_block_group(cache);
2593                 spin_unlock(&cache->lock);
2594
2595                 /*
2596                  * we need call btrfs_inc_block_group_ro() with scrubs_paused,
2597                  * to avoid deadlock caused by:
2598                  * btrfs_inc_block_group_ro()
2599                  * -> btrfs_wait_for_commit()
2600                  * -> btrfs_commit_transaction()
2601                  * -> btrfs_scrub_pause()
2602                  */
2603                 scrub_pause_on(fs_info);
2604
2605                 /*
2606                  * Don't do chunk preallocation for scrub.
2607                  *
2608                  * This is especially important for SYSTEM bgs, or we can hit
2609                  * -EFBIG from btrfs_finish_chunk_alloc() like:
2610                  * 1. The only SYSTEM bg is marked RO.
2611                  *    Since SYSTEM bg is small, that's pretty common.
2612                  * 2. New SYSTEM bg will be allocated
2613                  *    Due to regular version will allocate new chunk.
2614                  * 3. New SYSTEM bg is empty and will get cleaned up
2615                  *    Before cleanup really happens, it's marked RO again.
2616                  * 4. Empty SYSTEM bg get scrubbed
2617                  *    We go back to 2.
2618                  *
2619                  * This can easily boost the amount of SYSTEM chunks if cleaner
2620                  * thread can't be triggered fast enough, and use up all space
2621                  * of btrfs_super_block::sys_chunk_array
2622                  *
2623                  * While for dev replace, we need to try our best to mark block
2624                  * group RO, to prevent race between:
2625                  * - Write duplication
2626                  *   Contains latest data
2627                  * - Scrub copy
2628                  *   Contains data from commit tree
2629                  *
2630                  * If target block group is not marked RO, nocow writes can
2631                  * be overwritten by scrub copy, causing data corruption.
2632                  * So for dev-replace, it's not allowed to continue if a block
2633                  * group is not RO.
2634                  */
2635                 ret = btrfs_inc_block_group_ro(cache, sctx->is_dev_replace);
2636                 if (!ret && sctx->is_dev_replace) {
2637                         ret = finish_extent_writes_for_zoned(root, cache);
2638                         if (ret) {
2639                                 btrfs_dec_block_group_ro(cache);
2640                                 scrub_pause_off(fs_info);
2641                                 btrfs_put_block_group(cache);
2642                                 break;
2643                         }
2644                 }
2645
2646                 if (ret == 0) {
2647                         ro_set = 1;
2648                 } else if (ret == -ENOSPC && !sctx->is_dev_replace &&
2649                            !(cache->flags & BTRFS_BLOCK_GROUP_RAID56_MASK)) {
2650                         /*
2651                          * btrfs_inc_block_group_ro return -ENOSPC when it
2652                          * failed in creating new chunk for metadata.
2653                          * It is not a problem for scrub, because
2654                          * metadata are always cowed, and our scrub paused
2655                          * commit_transactions.
2656                          *
2657                          * For RAID56 chunks, we have to mark them read-only
2658                          * for scrub, as later we would use our own cache
2659                          * out of RAID56 realm.
2660                          * Thus we want the RAID56 bg to be marked RO to
2661                          * prevent RMW from screwing up out cache.
2662                          */
2663                         ro_set = 0;
2664                 } else if (ret == -ETXTBSY) {
2665                         btrfs_warn(fs_info,
2666                    "skipping scrub of block group %llu due to active swapfile",
2667                                    cache->start);
2668                         scrub_pause_off(fs_info);
2669                         ret = 0;
2670                         goto skip_unfreeze;
2671                 } else {
2672                         btrfs_warn(fs_info,
2673                                    "failed setting block group ro: %d", ret);
2674                         btrfs_unfreeze_block_group(cache);
2675                         btrfs_put_block_group(cache);
2676                         scrub_pause_off(fs_info);
2677                         break;
2678                 }
2679
2680                 /*
2681                  * Now the target block is marked RO, wait for nocow writes to
2682                  * finish before dev-replace.
2683                  * COW is fine, as COW never overwrites extents in commit tree.
2684                  */
2685                 if (sctx->is_dev_replace) {
2686                         btrfs_wait_nocow_writers(cache);
2687                         btrfs_wait_ordered_roots(fs_info, U64_MAX, cache->start,
2688                                         cache->length);
2689                 }
2690
2691                 scrub_pause_off(fs_info);
2692                 down_write(&dev_replace->rwsem);
2693                 dev_replace->cursor_right = found_key.offset + dev_extent_len;
2694                 dev_replace->cursor_left = found_key.offset;
2695                 dev_replace->item_needs_writeback = 1;
2696                 up_write(&dev_replace->rwsem);
2697
2698                 ret = scrub_chunk(sctx, cache, scrub_dev, found_key.offset,
2699                                   dev_extent_len);
2700                 if (sctx->is_dev_replace &&
2701                     !btrfs_finish_block_group_to_copy(dev_replace->srcdev,
2702                                                       cache, found_key.offset))
2703                         ro_set = 0;
2704
2705                 down_write(&dev_replace->rwsem);
2706                 dev_replace->cursor_left = dev_replace->cursor_right;
2707                 dev_replace->item_needs_writeback = 1;
2708                 up_write(&dev_replace->rwsem);
2709
2710                 if (ro_set)
2711                         btrfs_dec_block_group_ro(cache);
2712
2713                 /*
2714                  * We might have prevented the cleaner kthread from deleting
2715                  * this block group if it was already unused because we raced
2716                  * and set it to RO mode first. So add it back to the unused
2717                  * list, otherwise it might not ever be deleted unless a manual
2718                  * balance is triggered or it becomes used and unused again.
2719                  */
2720                 spin_lock(&cache->lock);
2721                 if (!test_bit(BLOCK_GROUP_FLAG_REMOVED, &cache->runtime_flags) &&
2722                     !cache->ro && cache->reserved == 0 && cache->used == 0) {
2723                         spin_unlock(&cache->lock);
2724                         if (btrfs_test_opt(fs_info, DISCARD_ASYNC))
2725                                 btrfs_discard_queue_work(&fs_info->discard_ctl,
2726                                                          cache);
2727                         else
2728                                 btrfs_mark_bg_unused(cache);
2729                 } else {
2730                         spin_unlock(&cache->lock);
2731                 }
2732 skip_unfreeze:
2733                 btrfs_unfreeze_block_group(cache);
2734                 btrfs_put_block_group(cache);
2735                 if (ret)
2736                         break;
2737                 if (sctx->is_dev_replace &&
2738                     atomic64_read(&dev_replace->num_write_errors) > 0) {
2739                         ret = -EIO;
2740                         break;
2741                 }
2742                 if (sctx->stat.malloc_errors > 0) {
2743                         ret = -ENOMEM;
2744                         break;
2745                 }
2746 skip:
2747                 key.offset = found_key.offset + dev_extent_len;
2748                 btrfs_release_path(path);
2749         }
2750
2751         btrfs_free_path(path);
2752
2753         return ret;
2754 }
2755
2756 static int scrub_one_super(struct scrub_ctx *sctx, struct btrfs_device *dev,
2757                            struct page *page, u64 physical, u64 generation)
2758 {
2759         struct btrfs_fs_info *fs_info = sctx->fs_info;
2760         struct bio_vec bvec;
2761         struct bio bio;
2762         struct btrfs_super_block *sb = page_address(page);
2763         int ret;
2764
2765         bio_init(&bio, dev->bdev, &bvec, 1, REQ_OP_READ);
2766         bio.bi_iter.bi_sector = physical >> SECTOR_SHIFT;
2767         __bio_add_page(&bio, page, BTRFS_SUPER_INFO_SIZE, 0);
2768         ret = submit_bio_wait(&bio);
2769         bio_uninit(&bio);
2770
2771         if (ret < 0)
2772                 return ret;
2773         ret = btrfs_check_super_csum(fs_info, sb);
2774         if (ret != 0) {
2775                 btrfs_err_rl(fs_info,
2776                         "super block at physical %llu devid %llu has bad csum",
2777                         physical, dev->devid);
2778                 return -EIO;
2779         }
2780         if (btrfs_super_generation(sb) != generation) {
2781                 btrfs_err_rl(fs_info,
2782 "super block at physical %llu devid %llu has bad generation %llu expect %llu",
2783                              physical, dev->devid,
2784                              btrfs_super_generation(sb), generation);
2785                 return -EUCLEAN;
2786         }
2787
2788         return btrfs_validate_super(fs_info, sb, -1);
2789 }
2790
2791 static noinline_for_stack int scrub_supers(struct scrub_ctx *sctx,
2792                                            struct btrfs_device *scrub_dev)
2793 {
2794         int     i;
2795         u64     bytenr;
2796         u64     gen;
2797         int ret = 0;
2798         struct page *page;
2799         struct btrfs_fs_info *fs_info = sctx->fs_info;
2800
2801         if (BTRFS_FS_ERROR(fs_info))
2802                 return -EROFS;
2803
2804         page = alloc_page(GFP_KERNEL);
2805         if (!page) {
2806                 spin_lock(&sctx->stat_lock);
2807                 sctx->stat.malloc_errors++;
2808                 spin_unlock(&sctx->stat_lock);
2809                 return -ENOMEM;
2810         }
2811
2812         /* Seed devices of a new filesystem has their own generation. */
2813         if (scrub_dev->fs_devices != fs_info->fs_devices)
2814                 gen = scrub_dev->generation;
2815         else
2816                 gen = btrfs_get_last_trans_committed(fs_info);
2817
2818         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
2819                 ret = btrfs_sb_log_location(scrub_dev, i, 0, &bytenr);
2820                 if (ret == -ENOENT)
2821                         break;
2822
2823                 if (ret) {
2824                         spin_lock(&sctx->stat_lock);
2825                         sctx->stat.super_errors++;
2826                         spin_unlock(&sctx->stat_lock);
2827                         continue;
2828                 }
2829
2830                 if (bytenr + BTRFS_SUPER_INFO_SIZE >
2831                     scrub_dev->commit_total_bytes)
2832                         break;
2833                 if (!btrfs_check_super_location(scrub_dev, bytenr))
2834                         continue;
2835
2836                 ret = scrub_one_super(sctx, scrub_dev, page, bytenr, gen);
2837                 if (ret) {
2838                         spin_lock(&sctx->stat_lock);
2839                         sctx->stat.super_errors++;
2840                         spin_unlock(&sctx->stat_lock);
2841                 }
2842         }
2843         __free_page(page);
2844         return 0;
2845 }
2846
2847 static void scrub_workers_put(struct btrfs_fs_info *fs_info)
2848 {
2849         if (refcount_dec_and_mutex_lock(&fs_info->scrub_workers_refcnt,
2850                                         &fs_info->scrub_lock)) {
2851                 struct workqueue_struct *scrub_workers = fs_info->scrub_workers;
2852
2853                 fs_info->scrub_workers = NULL;
2854                 mutex_unlock(&fs_info->scrub_lock);
2855
2856                 if (scrub_workers)
2857                         destroy_workqueue(scrub_workers);
2858         }
2859 }
2860
2861 /*
2862  * get a reference count on fs_info->scrub_workers. start worker if necessary
2863  */
2864 static noinline_for_stack int scrub_workers_get(struct btrfs_fs_info *fs_info)
2865 {
2866         struct workqueue_struct *scrub_workers = NULL;
2867         unsigned int flags = WQ_FREEZABLE | WQ_UNBOUND;
2868         int max_active = fs_info->thread_pool_size;
2869         int ret = -ENOMEM;
2870
2871         if (refcount_inc_not_zero(&fs_info->scrub_workers_refcnt))
2872                 return 0;
2873
2874         scrub_workers = alloc_workqueue("btrfs-scrub", flags, max_active);
2875         if (!scrub_workers)
2876                 return -ENOMEM;
2877
2878         mutex_lock(&fs_info->scrub_lock);
2879         if (refcount_read(&fs_info->scrub_workers_refcnt) == 0) {
2880                 ASSERT(fs_info->scrub_workers == NULL);
2881                 fs_info->scrub_workers = scrub_workers;
2882                 refcount_set(&fs_info->scrub_workers_refcnt, 1);
2883                 mutex_unlock(&fs_info->scrub_lock);
2884                 return 0;
2885         }
2886         /* Other thread raced in and created the workers for us */
2887         refcount_inc(&fs_info->scrub_workers_refcnt);
2888         mutex_unlock(&fs_info->scrub_lock);
2889
2890         ret = 0;
2891
2892         destroy_workqueue(scrub_workers);
2893         return ret;
2894 }
2895
2896 int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
2897                     u64 end, struct btrfs_scrub_progress *progress,
2898                     int readonly, int is_dev_replace)
2899 {
2900         struct btrfs_dev_lookup_args args = { .devid = devid };
2901         struct scrub_ctx *sctx;
2902         int ret;
2903         struct btrfs_device *dev;
2904         unsigned int nofs_flag;
2905         bool need_commit = false;
2906
2907         if (btrfs_fs_closing(fs_info))
2908                 return -EAGAIN;
2909
2910         /* At mount time we have ensured nodesize is in the range of [4K, 64K]. */
2911         ASSERT(fs_info->nodesize <= BTRFS_STRIPE_LEN);
2912
2913         /*
2914          * SCRUB_MAX_SECTORS_PER_BLOCK is calculated using the largest possible
2915          * value (max nodesize / min sectorsize), thus nodesize should always
2916          * be fine.
2917          */
2918         ASSERT(fs_info->nodesize <=
2919                SCRUB_MAX_SECTORS_PER_BLOCK << fs_info->sectorsize_bits);
2920
2921         /* Allocate outside of device_list_mutex */
2922         sctx = scrub_setup_ctx(fs_info, is_dev_replace);
2923         if (IS_ERR(sctx))
2924                 return PTR_ERR(sctx);
2925
2926         ret = scrub_workers_get(fs_info);
2927         if (ret)
2928                 goto out_free_ctx;
2929
2930         mutex_lock(&fs_info->fs_devices->device_list_mutex);
2931         dev = btrfs_find_device(fs_info->fs_devices, &args);
2932         if (!dev || (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state) &&
2933                      !is_dev_replace)) {
2934                 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2935                 ret = -ENODEV;
2936                 goto out;
2937         }
2938
2939         if (!is_dev_replace && !readonly &&
2940             !test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state)) {
2941                 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2942                 btrfs_err_in_rcu(fs_info,
2943                         "scrub on devid %llu: filesystem on %s is not writable",
2944                                  devid, btrfs_dev_name(dev));
2945                 ret = -EROFS;
2946                 goto out;
2947         }
2948
2949         mutex_lock(&fs_info->scrub_lock);
2950         if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &dev->dev_state) ||
2951             test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &dev->dev_state)) {
2952                 mutex_unlock(&fs_info->scrub_lock);
2953                 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2954                 ret = -EIO;
2955                 goto out;
2956         }
2957
2958         down_read(&fs_info->dev_replace.rwsem);
2959         if (dev->scrub_ctx ||
2960             (!is_dev_replace &&
2961              btrfs_dev_replace_is_ongoing(&fs_info->dev_replace))) {
2962                 up_read(&fs_info->dev_replace.rwsem);
2963                 mutex_unlock(&fs_info->scrub_lock);
2964                 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2965                 ret = -EINPROGRESS;
2966                 goto out;
2967         }
2968         up_read(&fs_info->dev_replace.rwsem);
2969
2970         sctx->readonly = readonly;
2971         dev->scrub_ctx = sctx;
2972         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2973
2974         /*
2975          * checking @scrub_pause_req here, we can avoid
2976          * race between committing transaction and scrubbing.
2977          */
2978         __scrub_blocked_if_needed(fs_info);
2979         atomic_inc(&fs_info->scrubs_running);
2980         mutex_unlock(&fs_info->scrub_lock);
2981
2982         /*
2983          * In order to avoid deadlock with reclaim when there is a transaction
2984          * trying to pause scrub, make sure we use GFP_NOFS for all the
2985          * allocations done at btrfs_scrub_sectors() and scrub_sectors_for_parity()
2986          * invoked by our callees. The pausing request is done when the
2987          * transaction commit starts, and it blocks the transaction until scrub
2988          * is paused (done at specific points at scrub_stripe() or right above
2989          * before incrementing fs_info->scrubs_running).
2990          */
2991         nofs_flag = memalloc_nofs_save();
2992         if (!is_dev_replace) {
2993                 u64 old_super_errors;
2994
2995                 spin_lock(&sctx->stat_lock);
2996                 old_super_errors = sctx->stat.super_errors;
2997                 spin_unlock(&sctx->stat_lock);
2998
2999                 btrfs_info(fs_info, "scrub: started on devid %llu", devid);
3000                 /*
3001                  * by holding device list mutex, we can
3002                  * kick off writing super in log tree sync.
3003                  */
3004                 mutex_lock(&fs_info->fs_devices->device_list_mutex);
3005                 ret = scrub_supers(sctx, dev);
3006                 mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3007
3008                 spin_lock(&sctx->stat_lock);
3009                 /*
3010                  * Super block errors found, but we can not commit transaction
3011                  * at current context, since btrfs_commit_transaction() needs
3012                  * to pause the current running scrub (hold by ourselves).
3013                  */
3014                 if (sctx->stat.super_errors > old_super_errors && !sctx->readonly)
3015                         need_commit = true;
3016                 spin_unlock(&sctx->stat_lock);
3017         }
3018
3019         if (!ret)
3020                 ret = scrub_enumerate_chunks(sctx, dev, start, end);
3021         memalloc_nofs_restore(nofs_flag);
3022
3023         atomic_dec(&fs_info->scrubs_running);
3024         wake_up(&fs_info->scrub_pause_wait);
3025
3026         if (progress)
3027                 memcpy(progress, &sctx->stat, sizeof(*progress));
3028
3029         if (!is_dev_replace)
3030                 btrfs_info(fs_info, "scrub: %s on devid %llu with status: %d",
3031                         ret ? "not finished" : "finished", devid, ret);
3032
3033         mutex_lock(&fs_info->scrub_lock);
3034         dev->scrub_ctx = NULL;
3035         mutex_unlock(&fs_info->scrub_lock);
3036
3037         scrub_workers_put(fs_info);
3038         scrub_put_ctx(sctx);
3039
3040         /*
3041          * We found some super block errors before, now try to force a
3042          * transaction commit, as scrub has finished.
3043          */
3044         if (need_commit) {
3045                 struct btrfs_trans_handle *trans;
3046
3047                 trans = btrfs_start_transaction(fs_info->tree_root, 0);
3048                 if (IS_ERR(trans)) {
3049                         ret = PTR_ERR(trans);
3050                         btrfs_err(fs_info,
3051         "scrub: failed to start transaction to fix super block errors: %d", ret);
3052                         return ret;
3053                 }
3054                 ret = btrfs_commit_transaction(trans);
3055                 if (ret < 0)
3056                         btrfs_err(fs_info,
3057         "scrub: failed to commit transaction to fix super block errors: %d", ret);
3058         }
3059         return ret;
3060 out:
3061         scrub_workers_put(fs_info);
3062 out_free_ctx:
3063         scrub_free_ctx(sctx);
3064
3065         return ret;
3066 }
3067
3068 void btrfs_scrub_pause(struct btrfs_fs_info *fs_info)
3069 {
3070         mutex_lock(&fs_info->scrub_lock);
3071         atomic_inc(&fs_info->scrub_pause_req);
3072         while (atomic_read(&fs_info->scrubs_paused) !=
3073                atomic_read(&fs_info->scrubs_running)) {
3074                 mutex_unlock(&fs_info->scrub_lock);
3075                 wait_event(fs_info->scrub_pause_wait,
3076                            atomic_read(&fs_info->scrubs_paused) ==
3077                            atomic_read(&fs_info->scrubs_running));
3078                 mutex_lock(&fs_info->scrub_lock);
3079         }
3080         mutex_unlock(&fs_info->scrub_lock);
3081 }
3082
3083 void btrfs_scrub_continue(struct btrfs_fs_info *fs_info)
3084 {
3085         atomic_dec(&fs_info->scrub_pause_req);
3086         wake_up(&fs_info->scrub_pause_wait);
3087 }
3088
3089 int btrfs_scrub_cancel(struct btrfs_fs_info *fs_info)
3090 {
3091         mutex_lock(&fs_info->scrub_lock);
3092         if (!atomic_read(&fs_info->scrubs_running)) {
3093                 mutex_unlock(&fs_info->scrub_lock);
3094                 return -ENOTCONN;
3095         }
3096
3097         atomic_inc(&fs_info->scrub_cancel_req);
3098         while (atomic_read(&fs_info->scrubs_running)) {
3099                 mutex_unlock(&fs_info->scrub_lock);
3100                 wait_event(fs_info->scrub_pause_wait,
3101                            atomic_read(&fs_info->scrubs_running) == 0);
3102                 mutex_lock(&fs_info->scrub_lock);
3103         }
3104         atomic_dec(&fs_info->scrub_cancel_req);
3105         mutex_unlock(&fs_info->scrub_lock);
3106
3107         return 0;
3108 }
3109
3110 int btrfs_scrub_cancel_dev(struct btrfs_device *dev)
3111 {
3112         struct btrfs_fs_info *fs_info = dev->fs_info;
3113         struct scrub_ctx *sctx;
3114
3115         mutex_lock(&fs_info->scrub_lock);
3116         sctx = dev->scrub_ctx;
3117         if (!sctx) {
3118                 mutex_unlock(&fs_info->scrub_lock);
3119                 return -ENOTCONN;
3120         }
3121         atomic_inc(&sctx->cancel_req);
3122         while (dev->scrub_ctx) {
3123                 mutex_unlock(&fs_info->scrub_lock);
3124                 wait_event(fs_info->scrub_pause_wait,
3125                            dev->scrub_ctx == NULL);
3126                 mutex_lock(&fs_info->scrub_lock);
3127         }
3128         mutex_unlock(&fs_info->scrub_lock);
3129
3130         return 0;
3131 }
3132
3133 int btrfs_scrub_progress(struct btrfs_fs_info *fs_info, u64 devid,
3134                          struct btrfs_scrub_progress *progress)
3135 {
3136         struct btrfs_dev_lookup_args args = { .devid = devid };
3137         struct btrfs_device *dev;
3138         struct scrub_ctx *sctx = NULL;
3139
3140         mutex_lock(&fs_info->fs_devices->device_list_mutex);
3141         dev = btrfs_find_device(fs_info->fs_devices, &args);
3142         if (dev)
3143                 sctx = dev->scrub_ctx;
3144         if (sctx)
3145                 memcpy(progress, &sctx->stat, sizeof(*progress));
3146         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3147
3148         return dev ? (sctx ? 0 : -ENOTCONN) : -ENODEV;
3149 }