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v6.8
   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
  41struct 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. */
  68struct 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
  88enum 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 */
 108struct 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
 185struct 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
 222struct 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
 231static 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
 249static 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;
 279error:
 280	release_scrub_stripe(stripe);
 281	return -ENOMEM;
 282}
 283
 284static void wait_scrub_stripe_io(struct scrub_stripe *stripe)
 285{
 286	wait_event(stripe->io_wait, atomic_read(&stripe->pending_io) == 0);
 287}
 288
 289static void scrub_put_ctx(struct scrub_ctx *sctx);
 290
 291static 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
 301static 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
 307static 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
 317static 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
 323static 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
 336static void scrub_put_ctx(struct scrub_ctx *sctx)
 337{
 338	if (refcount_dec_and_test(&sctx->refs))
 339		scrub_free_ctx(sctx);
 340}
 341
 342static 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
 383nomem:
 384	scrub_free_ctx(sctx);
 385	return ERR_PTR(-ENOMEM);
 386}
 387
 388static 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
 466err:
 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
 478static 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
 556out:
 557	btrfs_free_path(path);
 558}
 559
 560static 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
 582static 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
 590static 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
 598static 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
 689static 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. */
 751static 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
 764static 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 */
 783static 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
 811static 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
 817static 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
 866static 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
 911skip:
 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
 992static 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 */
1008static 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	int mirror;
1016	int i;
1017
1018	ASSERT(stripe->mirror_num > 0);
1019
1020	wait_scrub_stripe_io(stripe);
1021	scrub_verify_one_stripe(stripe, stripe->extent_sector_bitmap);
1022	/* Save the initial failed bitmap for later repair and report usage. */
1023	stripe->init_error_bitmap = stripe->error_bitmap;
1024	stripe->init_nr_io_errors = bitmap_weight(&stripe->io_error_bitmap,
1025						  stripe->nr_sectors);
1026	stripe->init_nr_csum_errors = bitmap_weight(&stripe->csum_error_bitmap,
1027						    stripe->nr_sectors);
1028	stripe->init_nr_meta_errors = bitmap_weight(&stripe->meta_error_bitmap,
1029						    stripe->nr_sectors);
1030
1031	if (bitmap_empty(&stripe->init_error_bitmap, stripe->nr_sectors))
1032		goto out;
1033
1034	/*
1035	 * Try all remaining mirrors.
1036	 *
1037	 * Here we still try to read as large block as possible, as this is
1038	 * faster and we have extra safety nets to rely on.
1039	 */
1040	for (mirror = calc_next_mirror(stripe->mirror_num, num_copies);
1041	     mirror != stripe->mirror_num;
1042	     mirror = calc_next_mirror(mirror, num_copies)) {
1043		const unsigned long old_error_bitmap = stripe->error_bitmap;
1044
1045		scrub_stripe_submit_repair_read(stripe, mirror,
1046						BTRFS_STRIPE_LEN, false);
1047		wait_scrub_stripe_io(stripe);
1048		scrub_verify_one_stripe(stripe, old_error_bitmap);
1049		if (bitmap_empty(&stripe->error_bitmap, stripe->nr_sectors))
1050			goto out;
1051	}
1052
1053	/*
1054	 * Last safety net, try re-checking all mirrors, including the failed
1055	 * one, sector-by-sector.
1056	 *
1057	 * As if one sector failed the drive's internal csum, the whole read
1058	 * containing the offending sector would be marked as error.
1059	 * Thus here we do sector-by-sector read.
1060	 *
1061	 * This can be slow, thus we only try it as the last resort.
1062	 */
1063
1064	for (i = 0, mirror = stripe->mirror_num;
1065	     i < num_copies;
1066	     i++, mirror = calc_next_mirror(mirror, num_copies)) {
1067		const unsigned long old_error_bitmap = stripe->error_bitmap;
1068
1069		scrub_stripe_submit_repair_read(stripe, mirror,
1070						fs_info->sectorsize, true);
1071		wait_scrub_stripe_io(stripe);
1072		scrub_verify_one_stripe(stripe, old_error_bitmap);
1073		if (bitmap_empty(&stripe->error_bitmap, stripe->nr_sectors))
1074			goto out;
1075	}
1076out:
1077	/*
1078	 * Submit the repaired sectors.  For zoned case, we cannot do repair
1079	 * in-place, but queue the bg to be relocated.
1080	 */
1081	if (btrfs_is_zoned(fs_info)) {
1082		if (!bitmap_empty(&stripe->error_bitmap, stripe->nr_sectors))
 
 
1083			btrfs_repair_one_zone(fs_info, sctx->stripes[0].bg->start);
1084	} else if (!sctx->readonly) {
1085		unsigned long repaired;
1086
1087		bitmap_andnot(&repaired, &stripe->init_error_bitmap,
1088			      &stripe->error_bitmap, stripe->nr_sectors);
1089		scrub_write_sectors(sctx, stripe, repaired, false);
1090		wait_scrub_stripe_io(stripe);
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
1098static 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
1126static 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
1152static 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 */
1194static 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 */
1232static 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 */
1291static 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 */
1333static 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 */
1371static 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
1394	ASSERT(ret > 0);
1395	/*
1396	 * Here we intentionally pass 0 as @min_objectid, as there could be
1397	 * an extent item starting before @search_start.
1398	 */
1399	ret = btrfs_previous_extent_item(extent_root, path, 0);
1400	if (ret < 0)
1401		return ret;
1402	/*
1403	 * No matter whether we have found an extent item, the next loop will
1404	 * properly do every check on the key.
1405	 */
1406search_forward:
1407	while (true) {
1408		btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1409		if (key.objectid >= search_start + search_len)
1410			break;
1411		if (key.type != BTRFS_METADATA_ITEM_KEY &&
1412		    key.type != BTRFS_EXTENT_ITEM_KEY)
1413			goto next;
1414
1415		ret = compare_extent_item_range(path, search_start, search_len);
1416		if (ret == 0)
1417			return ret;
1418		if (ret > 0)
1419			break;
1420next:
1421		ret = btrfs_next_item(extent_root, path);
1422		if (ret) {
1423			/* Either no more items or a fatal error. */
1424			btrfs_release_path(path);
1425			return ret;
1426		}
1427	}
1428	btrfs_release_path(path);
1429	return 1;
1430}
1431
1432static void get_extent_info(struct btrfs_path *path, u64 *extent_start_ret,
1433			    u64 *size_ret, u64 *flags_ret, u64 *generation_ret)
1434{
1435	struct btrfs_key key;
1436	struct btrfs_extent_item *ei;
1437
1438	btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1439	ASSERT(key.type == BTRFS_METADATA_ITEM_KEY ||
1440	       key.type == BTRFS_EXTENT_ITEM_KEY);
1441	*extent_start_ret = key.objectid;
1442	if (key.type == BTRFS_METADATA_ITEM_KEY)
1443		*size_ret = path->nodes[0]->fs_info->nodesize;
1444	else
1445		*size_ret = key.offset;
1446	ei = btrfs_item_ptr(path->nodes[0], path->slots[0], struct btrfs_extent_item);
1447	*flags_ret = btrfs_extent_flags(path->nodes[0], ei);
1448	*generation_ret = btrfs_extent_generation(path->nodes[0], ei);
1449}
1450
1451static int sync_write_pointer_for_zoned(struct scrub_ctx *sctx, u64 logical,
1452					u64 physical, u64 physical_end)
1453{
1454	struct btrfs_fs_info *fs_info = sctx->fs_info;
1455	int ret = 0;
1456
1457	if (!btrfs_is_zoned(fs_info))
1458		return 0;
1459
1460	mutex_lock(&sctx->wr_lock);
1461	if (sctx->write_pointer < physical_end) {
1462		ret = btrfs_sync_zone_write_pointer(sctx->wr_tgtdev, logical,
1463						    physical,
1464						    sctx->write_pointer);
1465		if (ret)
1466			btrfs_err(fs_info,
1467				  "zoned: failed to recover write pointer");
1468	}
1469	mutex_unlock(&sctx->wr_lock);
1470	btrfs_dev_clear_zone_empty(sctx->wr_tgtdev, physical);
1471
1472	return ret;
1473}
1474
1475static void fill_one_extent_info(struct btrfs_fs_info *fs_info,
1476				 struct scrub_stripe *stripe,
1477				 u64 extent_start, u64 extent_len,
1478				 u64 extent_flags, u64 extent_gen)
1479{
1480	for (u64 cur_logical = max(stripe->logical, extent_start);
1481	     cur_logical < min(stripe->logical + BTRFS_STRIPE_LEN,
1482			       extent_start + extent_len);
1483	     cur_logical += fs_info->sectorsize) {
1484		const int nr_sector = (cur_logical - stripe->logical) >>
1485				      fs_info->sectorsize_bits;
1486		struct scrub_sector_verification *sector =
1487						&stripe->sectors[nr_sector];
1488
1489		set_bit(nr_sector, &stripe->extent_sector_bitmap);
1490		if (extent_flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
1491			sector->is_metadata = true;
1492			sector->generation = extent_gen;
1493		}
1494	}
1495}
1496
1497static void scrub_stripe_reset_bitmaps(struct scrub_stripe *stripe)
1498{
1499	stripe->extent_sector_bitmap = 0;
1500	stripe->init_error_bitmap = 0;
1501	stripe->init_nr_io_errors = 0;
1502	stripe->init_nr_csum_errors = 0;
1503	stripe->init_nr_meta_errors = 0;
1504	stripe->error_bitmap = 0;
1505	stripe->io_error_bitmap = 0;
1506	stripe->csum_error_bitmap = 0;
1507	stripe->meta_error_bitmap = 0;
1508}
1509
1510/*
1511 * Locate one stripe which has at least one extent in its range.
1512 *
1513 * Return 0 if found such stripe, and store its info into @stripe.
1514 * Return >0 if there is no such stripe in the specified range.
1515 * Return <0 for error.
1516 */
1517static int scrub_find_fill_first_stripe(struct btrfs_block_group *bg,
1518					struct btrfs_path *extent_path,
1519					struct btrfs_path *csum_path,
1520					struct btrfs_device *dev, u64 physical,
1521					int mirror_num, u64 logical_start,
1522					u32 logical_len,
1523					struct scrub_stripe *stripe)
1524{
1525	struct btrfs_fs_info *fs_info = bg->fs_info;
1526	struct btrfs_root *extent_root = btrfs_extent_root(fs_info, bg->start);
1527	struct btrfs_root *csum_root = btrfs_csum_root(fs_info, bg->start);
1528	const u64 logical_end = logical_start + logical_len;
1529	u64 cur_logical = logical_start;
1530	u64 stripe_end;
1531	u64 extent_start;
1532	u64 extent_len;
1533	u64 extent_flags;
1534	u64 extent_gen;
1535	int ret;
1536
1537	memset(stripe->sectors, 0, sizeof(struct scrub_sector_verification) *
1538				   stripe->nr_sectors);
1539	scrub_stripe_reset_bitmaps(stripe);
1540
1541	/* The range must be inside the bg. */
1542	ASSERT(logical_start >= bg->start && logical_end <= bg->start + bg->length);
1543
1544	ret = find_first_extent_item(extent_root, extent_path, logical_start,
1545				     logical_len);
1546	/* Either error or not found. */
1547	if (ret)
1548		goto out;
1549	get_extent_info(extent_path, &extent_start, &extent_len, &extent_flags,
1550			&extent_gen);
1551	if (extent_flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1552		stripe->nr_meta_extents++;
1553	if (extent_flags & BTRFS_EXTENT_FLAG_DATA)
1554		stripe->nr_data_extents++;
1555	cur_logical = max(extent_start, cur_logical);
1556
1557	/*
1558	 * Round down to stripe boundary.
1559	 *
1560	 * The extra calculation against bg->start is to handle block groups
1561	 * whose logical bytenr is not BTRFS_STRIPE_LEN aligned.
1562	 */
1563	stripe->logical = round_down(cur_logical - bg->start, BTRFS_STRIPE_LEN) +
1564			  bg->start;
1565	stripe->physical = physical + stripe->logical - logical_start;
1566	stripe->dev = dev;
1567	stripe->bg = bg;
1568	stripe->mirror_num = mirror_num;
1569	stripe_end = stripe->logical + BTRFS_STRIPE_LEN - 1;
1570
1571	/* Fill the first extent info into stripe->sectors[] array. */
1572	fill_one_extent_info(fs_info, stripe, extent_start, extent_len,
1573			     extent_flags, extent_gen);
1574	cur_logical = extent_start + extent_len;
1575
1576	/* Fill the extent info for the remaining sectors. */
1577	while (cur_logical <= stripe_end) {
1578		ret = find_first_extent_item(extent_root, extent_path, cur_logical,
1579					     stripe_end - cur_logical + 1);
1580		if (ret < 0)
1581			goto out;
1582		if (ret > 0) {
1583			ret = 0;
1584			break;
1585		}
1586		get_extent_info(extent_path, &extent_start, &extent_len,
1587				&extent_flags, &extent_gen);
1588		if (extent_flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1589			stripe->nr_meta_extents++;
1590		if (extent_flags & BTRFS_EXTENT_FLAG_DATA)
1591			stripe->nr_data_extents++;
1592		fill_one_extent_info(fs_info, stripe, extent_start, extent_len,
1593				     extent_flags, extent_gen);
1594		cur_logical = extent_start + extent_len;
1595	}
1596
1597	/* Now fill the data csum. */
1598	if (bg->flags & BTRFS_BLOCK_GROUP_DATA) {
1599		int sector_nr;
1600		unsigned long csum_bitmap = 0;
1601
1602		/* Csum space should have already been allocated. */
1603		ASSERT(stripe->csums);
1604
1605		/*
1606		 * Our csum bitmap should be large enough, as BTRFS_STRIPE_LEN
1607		 * should contain at most 16 sectors.
1608		 */
1609		ASSERT(BITS_PER_LONG >= BTRFS_STRIPE_LEN >> fs_info->sectorsize_bits);
1610
1611		ret = btrfs_lookup_csums_bitmap(csum_root, csum_path,
1612						stripe->logical, stripe_end,
1613						stripe->csums, &csum_bitmap);
1614		if (ret < 0)
1615			goto out;
1616		if (ret > 0)
1617			ret = 0;
1618
1619		for_each_set_bit(sector_nr, &csum_bitmap, stripe->nr_sectors) {
1620			stripe->sectors[sector_nr].csum = stripe->csums +
1621				sector_nr * fs_info->csum_size;
1622		}
1623	}
1624	set_bit(SCRUB_STRIPE_FLAG_INITIALIZED, &stripe->state);
1625out:
1626	return ret;
1627}
1628
1629static void scrub_reset_stripe(struct scrub_stripe *stripe)
1630{
1631	scrub_stripe_reset_bitmaps(stripe);
1632
1633	stripe->nr_meta_extents = 0;
1634	stripe->nr_data_extents = 0;
1635	stripe->state = 0;
1636
1637	for (int i = 0; i < stripe->nr_sectors; i++) {
1638		stripe->sectors[i].is_metadata = false;
1639		stripe->sectors[i].csum = NULL;
1640		stripe->sectors[i].generation = 0;
1641	}
1642}
1643
1644static void scrub_submit_extent_sector_read(struct scrub_ctx *sctx,
1645					    struct scrub_stripe *stripe)
1646{
1647	struct btrfs_fs_info *fs_info = stripe->bg->fs_info;
1648	struct btrfs_bio *bbio = NULL;
1649	unsigned int nr_sectors = min(BTRFS_STRIPE_LEN, stripe->bg->start +
1650				      stripe->bg->length - stripe->logical) >>
1651				  fs_info->sectorsize_bits;
1652	u64 stripe_len = BTRFS_STRIPE_LEN;
1653	int mirror = stripe->mirror_num;
1654	int i;
1655
1656	atomic_inc(&stripe->pending_io);
1657
1658	for_each_set_bit(i, &stripe->extent_sector_bitmap, stripe->nr_sectors) {
1659		struct page *page = scrub_stripe_get_page(stripe, i);
1660		unsigned int pgoff = scrub_stripe_get_page_offset(stripe, i);
1661
1662		/* We're beyond the chunk boundary, no need to read anymore. */
1663		if (i >= nr_sectors)
1664			break;
1665
1666		/* The current sector cannot be merged, submit the bio. */
1667		if (bbio &&
1668		    ((i > 0 &&
1669		      !test_bit(i - 1, &stripe->extent_sector_bitmap)) ||
1670		     bbio->bio.bi_iter.bi_size >= stripe_len)) {
1671			ASSERT(bbio->bio.bi_iter.bi_size);
1672			atomic_inc(&stripe->pending_io);
1673			btrfs_submit_bio(bbio, mirror);
1674			bbio = NULL;
1675		}
1676
1677		if (!bbio) {
1678			struct btrfs_io_stripe io_stripe = {};
1679			struct btrfs_io_context *bioc = NULL;
1680			const u64 logical = stripe->logical +
1681					    (i << fs_info->sectorsize_bits);
1682			int err;
1683
1684			bbio = btrfs_bio_alloc(stripe->nr_sectors, REQ_OP_READ,
1685					       fs_info, scrub_read_endio, stripe);
1686			bbio->bio.bi_iter.bi_sector = logical >> SECTOR_SHIFT;
1687
1688			io_stripe.is_scrub = true;
1689			err = btrfs_map_block(fs_info, BTRFS_MAP_READ, logical,
1690					      &stripe_len, &bioc, &io_stripe,
1691					      &mirror);
1692			btrfs_put_bioc(bioc);
1693			if (err) {
1694				btrfs_bio_end_io(bbio,
1695						 errno_to_blk_status(err));
1696				return;
1697			}
1698		}
1699
1700		__bio_add_page(&bbio->bio, page, fs_info->sectorsize, pgoff);
1701	}
1702
1703	if (bbio) {
1704		ASSERT(bbio->bio.bi_iter.bi_size);
1705		atomic_inc(&stripe->pending_io);
1706		btrfs_submit_bio(bbio, mirror);
1707	}
1708
1709	if (atomic_dec_and_test(&stripe->pending_io)) {
1710		wake_up(&stripe->io_wait);
1711		INIT_WORK(&stripe->work, scrub_stripe_read_repair_worker);
1712		queue_work(stripe->bg->fs_info->scrub_workers, &stripe->work);
1713	}
1714}
1715
1716static void scrub_submit_initial_read(struct scrub_ctx *sctx,
1717				      struct scrub_stripe *stripe)
1718{
1719	struct btrfs_fs_info *fs_info = sctx->fs_info;
1720	struct btrfs_bio *bbio;
1721	unsigned int nr_sectors = min(BTRFS_STRIPE_LEN, stripe->bg->start +
1722				      stripe->bg->length - stripe->logical) >>
1723				  fs_info->sectorsize_bits;
1724	int mirror = stripe->mirror_num;
1725
1726	ASSERT(stripe->bg);
1727	ASSERT(stripe->mirror_num > 0);
1728	ASSERT(test_bit(SCRUB_STRIPE_FLAG_INITIALIZED, &stripe->state));
1729
1730	if (btrfs_need_stripe_tree_update(fs_info, stripe->bg->flags)) {
1731		scrub_submit_extent_sector_read(sctx, stripe);
1732		return;
1733	}
1734
1735	bbio = btrfs_bio_alloc(SCRUB_STRIPE_PAGES, REQ_OP_READ, fs_info,
1736			       scrub_read_endio, stripe);
1737
1738	bbio->bio.bi_iter.bi_sector = stripe->logical >> SECTOR_SHIFT;
1739	/* Read the whole range inside the chunk boundary. */
1740	for (unsigned int cur = 0; cur < nr_sectors; cur++) {
1741		struct page *page = scrub_stripe_get_page(stripe, cur);
1742		unsigned int pgoff = scrub_stripe_get_page_offset(stripe, cur);
1743		int ret;
1744
1745		ret = bio_add_page(&bbio->bio, page, fs_info->sectorsize, pgoff);
1746		/* We should have allocated enough bio vectors. */
1747		ASSERT(ret == fs_info->sectorsize);
1748	}
1749	atomic_inc(&stripe->pending_io);
1750
1751	/*
1752	 * For dev-replace, either user asks to avoid the source dev, or
1753	 * the device is missing, we try the next mirror instead.
1754	 */
1755	if (sctx->is_dev_replace &&
1756	    (fs_info->dev_replace.cont_reading_from_srcdev_mode ==
1757	     BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_AVOID ||
1758	     !stripe->dev->bdev)) {
1759		int num_copies = btrfs_num_copies(fs_info, stripe->bg->start,
1760						  stripe->bg->length);
1761
1762		mirror = calc_next_mirror(mirror, num_copies);
1763	}
1764	btrfs_submit_bio(bbio, mirror);
1765}
1766
1767static bool stripe_has_metadata_error(struct scrub_stripe *stripe)
1768{
1769	int i;
1770
1771	for_each_set_bit(i, &stripe->error_bitmap, stripe->nr_sectors) {
1772		if (stripe->sectors[i].is_metadata) {
1773			struct btrfs_fs_info *fs_info = stripe->bg->fs_info;
1774
1775			btrfs_err(fs_info,
1776			"stripe %llu has unrepaired metadata sector at %llu",
1777				  stripe->logical,
1778				  stripe->logical + (i << fs_info->sectorsize_bits));
1779			return true;
1780		}
1781	}
1782	return false;
1783}
1784
1785static void submit_initial_group_read(struct scrub_ctx *sctx,
1786				      unsigned int first_slot,
1787				      unsigned int nr_stripes)
1788{
1789	struct blk_plug plug;
1790
1791	ASSERT(first_slot < SCRUB_TOTAL_STRIPES);
1792	ASSERT(first_slot + nr_stripes <= SCRUB_TOTAL_STRIPES);
1793
1794	scrub_throttle_dev_io(sctx, sctx->stripes[0].dev,
1795			      btrfs_stripe_nr_to_offset(nr_stripes));
1796	blk_start_plug(&plug);
1797	for (int i = 0; i < nr_stripes; i++) {
1798		struct scrub_stripe *stripe = &sctx->stripes[first_slot + i];
1799
1800		/* Those stripes should be initialized. */
1801		ASSERT(test_bit(SCRUB_STRIPE_FLAG_INITIALIZED, &stripe->state));
1802		scrub_submit_initial_read(sctx, stripe);
1803	}
1804	blk_finish_plug(&plug);
1805}
1806
1807static int flush_scrub_stripes(struct scrub_ctx *sctx)
1808{
1809	struct btrfs_fs_info *fs_info = sctx->fs_info;
1810	struct scrub_stripe *stripe;
1811	const int nr_stripes = sctx->cur_stripe;
1812	int ret = 0;
1813
1814	if (!nr_stripes)
1815		return 0;
1816
1817	ASSERT(test_bit(SCRUB_STRIPE_FLAG_INITIALIZED, &sctx->stripes[0].state));
1818
1819	/* Submit the stripes which are populated but not submitted. */
1820	if (nr_stripes % SCRUB_STRIPES_PER_GROUP) {
1821		const int first_slot = round_down(nr_stripes, SCRUB_STRIPES_PER_GROUP);
1822
1823		submit_initial_group_read(sctx, first_slot, nr_stripes - first_slot);
1824	}
1825
1826	for (int i = 0; i < nr_stripes; i++) {
1827		stripe = &sctx->stripes[i];
1828
1829		wait_event(stripe->repair_wait,
1830			   test_bit(SCRUB_STRIPE_FLAG_REPAIR_DONE, &stripe->state));
1831	}
1832
1833	/* Submit for dev-replace. */
1834	if (sctx->is_dev_replace) {
1835		/*
1836		 * For dev-replace, if we know there is something wrong with
1837		 * metadata, we should immediately abort.
1838		 */
1839		for (int i = 0; i < nr_stripes; i++) {
1840			if (stripe_has_metadata_error(&sctx->stripes[i])) {
1841				ret = -EIO;
1842				goto out;
1843			}
1844		}
1845		for (int i = 0; i < nr_stripes; i++) {
1846			unsigned long good;
1847
1848			stripe = &sctx->stripes[i];
1849
1850			ASSERT(stripe->dev == fs_info->dev_replace.srcdev);
1851
1852			bitmap_andnot(&good, &stripe->extent_sector_bitmap,
1853				      &stripe->error_bitmap, stripe->nr_sectors);
1854			scrub_write_sectors(sctx, stripe, good, true);
1855		}
1856	}
1857
1858	/* Wait for the above writebacks to finish. */
1859	for (int i = 0; i < nr_stripes; i++) {
1860		stripe = &sctx->stripes[i];
1861
1862		wait_scrub_stripe_io(stripe);
1863		scrub_reset_stripe(stripe);
1864	}
1865out:
1866	sctx->cur_stripe = 0;
1867	return ret;
1868}
1869
1870static void raid56_scrub_wait_endio(struct bio *bio)
1871{
1872	complete(bio->bi_private);
1873}
1874
1875static int queue_scrub_stripe(struct scrub_ctx *sctx, struct btrfs_block_group *bg,
1876			      struct btrfs_device *dev, int mirror_num,
1877			      u64 logical, u32 length, u64 physical,
1878			      u64 *found_logical_ret)
1879{
1880	struct scrub_stripe *stripe;
1881	int ret;
1882
1883	/*
1884	 * There should always be one slot left, as caller filling the last
1885	 * slot should flush them all.
1886	 */
1887	ASSERT(sctx->cur_stripe < SCRUB_TOTAL_STRIPES);
1888
1889	/* @found_logical_ret must be specified. */
1890	ASSERT(found_logical_ret);
1891
1892	stripe = &sctx->stripes[sctx->cur_stripe];
1893	scrub_reset_stripe(stripe);
1894	ret = scrub_find_fill_first_stripe(bg, &sctx->extent_path,
1895					   &sctx->csum_path, dev, physical,
1896					   mirror_num, logical, length, stripe);
1897	/* Either >0 as no more extents or <0 for error. */
1898	if (ret)
1899		return ret;
1900	*found_logical_ret = stripe->logical;
1901	sctx->cur_stripe++;
1902
1903	/* We filled one group, submit it. */
1904	if (sctx->cur_stripe % SCRUB_STRIPES_PER_GROUP == 0) {
1905		const int first_slot = sctx->cur_stripe - SCRUB_STRIPES_PER_GROUP;
1906
1907		submit_initial_group_read(sctx, first_slot, SCRUB_STRIPES_PER_GROUP);
1908	}
1909
1910	/* Last slot used, flush them all. */
1911	if (sctx->cur_stripe == SCRUB_TOTAL_STRIPES)
1912		return flush_scrub_stripes(sctx);
1913	return 0;
1914}
1915
1916static int scrub_raid56_parity_stripe(struct scrub_ctx *sctx,
1917				      struct btrfs_device *scrub_dev,
1918				      struct btrfs_block_group *bg,
1919				      struct btrfs_chunk_map *map,
1920				      u64 full_stripe_start)
1921{
1922	DECLARE_COMPLETION_ONSTACK(io_done);
1923	struct btrfs_fs_info *fs_info = sctx->fs_info;
1924	struct btrfs_raid_bio *rbio;
1925	struct btrfs_io_context *bioc = NULL;
1926	struct btrfs_path extent_path = { 0 };
1927	struct btrfs_path csum_path = { 0 };
1928	struct bio *bio;
1929	struct scrub_stripe *stripe;
1930	bool all_empty = true;
1931	const int data_stripes = nr_data_stripes(map);
1932	unsigned long extent_bitmap = 0;
1933	u64 length = btrfs_stripe_nr_to_offset(data_stripes);
1934	int ret;
1935
1936	ASSERT(sctx->raid56_data_stripes);
1937
1938	/*
1939	 * For data stripe search, we cannot re-use the same extent/csum paths,
1940	 * as the data stripe bytenr may be smaller than previous extent.  Thus
1941	 * we have to use our own extent/csum paths.
1942	 */
1943	extent_path.search_commit_root = 1;
1944	extent_path.skip_locking = 1;
1945	csum_path.search_commit_root = 1;
1946	csum_path.skip_locking = 1;
1947
1948	for (int i = 0; i < data_stripes; i++) {
1949		int stripe_index;
1950		int rot;
1951		u64 physical;
1952
1953		stripe = &sctx->raid56_data_stripes[i];
1954		rot = div_u64(full_stripe_start - bg->start,
1955			      data_stripes) >> BTRFS_STRIPE_LEN_SHIFT;
1956		stripe_index = (i + rot) % map->num_stripes;
1957		physical = map->stripes[stripe_index].physical +
1958			   btrfs_stripe_nr_to_offset(rot);
1959
1960		scrub_reset_stripe(stripe);
1961		set_bit(SCRUB_STRIPE_FLAG_NO_REPORT, &stripe->state);
1962		ret = scrub_find_fill_first_stripe(bg, &extent_path, &csum_path,
1963				map->stripes[stripe_index].dev, physical, 1,
1964				full_stripe_start + btrfs_stripe_nr_to_offset(i),
1965				BTRFS_STRIPE_LEN, stripe);
1966		if (ret < 0)
1967			goto out;
1968		/*
1969		 * No extent in this data stripe, need to manually mark them
1970		 * initialized to make later read submission happy.
1971		 */
1972		if (ret > 0) {
1973			stripe->logical = full_stripe_start +
1974					  btrfs_stripe_nr_to_offset(i);
1975			stripe->dev = map->stripes[stripe_index].dev;
1976			stripe->mirror_num = 1;
1977			set_bit(SCRUB_STRIPE_FLAG_INITIALIZED, &stripe->state);
1978		}
1979	}
1980
1981	/* Check if all data stripes are empty. */
1982	for (int i = 0; i < data_stripes; i++) {
1983		stripe = &sctx->raid56_data_stripes[i];
1984		if (!bitmap_empty(&stripe->extent_sector_bitmap, stripe->nr_sectors)) {
1985			all_empty = false;
1986			break;
1987		}
1988	}
1989	if (all_empty) {
1990		ret = 0;
1991		goto out;
1992	}
1993
1994	for (int i = 0; i < data_stripes; i++) {
1995		stripe = &sctx->raid56_data_stripes[i];
1996		scrub_submit_initial_read(sctx, stripe);
1997	}
1998	for (int i = 0; i < data_stripes; i++) {
1999		stripe = &sctx->raid56_data_stripes[i];
2000
2001		wait_event(stripe->repair_wait,
2002			   test_bit(SCRUB_STRIPE_FLAG_REPAIR_DONE, &stripe->state));
2003	}
2004	/* For now, no zoned support for RAID56. */
2005	ASSERT(!btrfs_is_zoned(sctx->fs_info));
2006
2007	/*
2008	 * Now all data stripes are properly verified. Check if we have any
2009	 * unrepaired, if so abort immediately or we could further corrupt the
2010	 * P/Q stripes.
2011	 *
2012	 * During the loop, also populate extent_bitmap.
2013	 */
2014	for (int i = 0; i < data_stripes; i++) {
2015		unsigned long error;
2016
2017		stripe = &sctx->raid56_data_stripes[i];
2018
2019		/*
2020		 * We should only check the errors where there is an extent.
2021		 * As we may hit an empty data stripe while it's missing.
2022		 */
2023		bitmap_and(&error, &stripe->error_bitmap,
2024			   &stripe->extent_sector_bitmap, stripe->nr_sectors);
2025		if (!bitmap_empty(&error, stripe->nr_sectors)) {
2026			btrfs_err(fs_info,
2027"unrepaired sectors detected, full stripe %llu data stripe %u errors %*pbl",
2028				  full_stripe_start, i, stripe->nr_sectors,
2029				  &error);
2030			ret = -EIO;
2031			goto out;
2032		}
2033		bitmap_or(&extent_bitmap, &extent_bitmap,
2034			  &stripe->extent_sector_bitmap, stripe->nr_sectors);
2035	}
2036
2037	/* Now we can check and regenerate the P/Q stripe. */
2038	bio = bio_alloc(NULL, 1, REQ_OP_READ, GFP_NOFS);
2039	bio->bi_iter.bi_sector = full_stripe_start >> SECTOR_SHIFT;
2040	bio->bi_private = &io_done;
2041	bio->bi_end_io = raid56_scrub_wait_endio;
2042
2043	btrfs_bio_counter_inc_blocked(fs_info);
2044	ret = btrfs_map_block(fs_info, BTRFS_MAP_WRITE, full_stripe_start,
2045			      &length, &bioc, NULL, NULL);
2046	if (ret < 0) {
2047		btrfs_put_bioc(bioc);
2048		btrfs_bio_counter_dec(fs_info);
2049		goto out;
2050	}
2051	rbio = raid56_parity_alloc_scrub_rbio(bio, bioc, scrub_dev, &extent_bitmap,
2052				BTRFS_STRIPE_LEN >> fs_info->sectorsize_bits);
2053	btrfs_put_bioc(bioc);
2054	if (!rbio) {
2055		ret = -ENOMEM;
2056		btrfs_bio_counter_dec(fs_info);
2057		goto out;
2058	}
2059	/* Use the recovered stripes as cache to avoid read them from disk again. */
2060	for (int i = 0; i < data_stripes; i++) {
2061		stripe = &sctx->raid56_data_stripes[i];
2062
2063		raid56_parity_cache_data_pages(rbio, stripe->pages,
2064				full_stripe_start + (i << BTRFS_STRIPE_LEN_SHIFT));
2065	}
2066	raid56_parity_submit_scrub_rbio(rbio);
2067	wait_for_completion_io(&io_done);
2068	ret = blk_status_to_errno(bio->bi_status);
2069	bio_put(bio);
2070	btrfs_bio_counter_dec(fs_info);
2071
2072	btrfs_release_path(&extent_path);
2073	btrfs_release_path(&csum_path);
2074out:
2075	return ret;
2076}
2077
2078/*
2079 * Scrub one range which can only has simple mirror based profile.
2080 * (Including all range in SINGLE/DUP/RAID1/RAID1C*, and each stripe in
2081 *  RAID0/RAID10).
2082 *
2083 * Since we may need to handle a subset of block group, we need @logical_start
2084 * and @logical_length parameter.
2085 */
2086static int scrub_simple_mirror(struct scrub_ctx *sctx,
2087			       struct btrfs_block_group *bg,
2088			       struct btrfs_chunk_map *map,
2089			       u64 logical_start, u64 logical_length,
2090			       struct btrfs_device *device,
2091			       u64 physical, int mirror_num)
2092{
2093	struct btrfs_fs_info *fs_info = sctx->fs_info;
2094	const u64 logical_end = logical_start + logical_length;
2095	u64 cur_logical = logical_start;
2096	int ret;
2097
2098	/* The range must be inside the bg */
2099	ASSERT(logical_start >= bg->start && logical_end <= bg->start + bg->length);
2100
2101	/* Go through each extent items inside the logical range */
2102	while (cur_logical < logical_end) {
2103		u64 found_logical = U64_MAX;
2104		u64 cur_physical = physical + cur_logical - logical_start;
2105
2106		/* Canceled? */
2107		if (atomic_read(&fs_info->scrub_cancel_req) ||
2108		    atomic_read(&sctx->cancel_req)) {
2109			ret = -ECANCELED;
2110			break;
2111		}
2112		/* Paused? */
2113		if (atomic_read(&fs_info->scrub_pause_req)) {
2114			/* Push queued extents */
2115			scrub_blocked_if_needed(fs_info);
2116		}
2117		/* Block group removed? */
2118		spin_lock(&bg->lock);
2119		if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &bg->runtime_flags)) {
2120			spin_unlock(&bg->lock);
2121			ret = 0;
2122			break;
2123		}
2124		spin_unlock(&bg->lock);
2125
2126		ret = queue_scrub_stripe(sctx, bg, device, mirror_num,
2127					 cur_logical, logical_end - cur_logical,
2128					 cur_physical, &found_logical);
2129		if (ret > 0) {
2130			/* No more extent, just update the accounting */
2131			sctx->stat.last_physical = physical + logical_length;
2132			ret = 0;
2133			break;
2134		}
2135		if (ret < 0)
2136			break;
2137
2138		/* queue_scrub_stripe() returned 0, @found_logical must be updated. */
2139		ASSERT(found_logical != U64_MAX);
2140		cur_logical = found_logical + BTRFS_STRIPE_LEN;
2141
2142		/* Don't hold CPU for too long time */
2143		cond_resched();
2144	}
2145	return ret;
2146}
2147
2148/* Calculate the full stripe length for simple stripe based profiles */
2149static u64 simple_stripe_full_stripe_len(const struct btrfs_chunk_map *map)
2150{
2151	ASSERT(map->type & (BTRFS_BLOCK_GROUP_RAID0 |
2152			    BTRFS_BLOCK_GROUP_RAID10));
2153
2154	return btrfs_stripe_nr_to_offset(map->num_stripes / map->sub_stripes);
2155}
2156
2157/* Get the logical bytenr for the stripe */
2158static u64 simple_stripe_get_logical(struct btrfs_chunk_map *map,
2159				     struct btrfs_block_group *bg,
2160				     int stripe_index)
2161{
2162	ASSERT(map->type & (BTRFS_BLOCK_GROUP_RAID0 |
2163			    BTRFS_BLOCK_GROUP_RAID10));
2164	ASSERT(stripe_index < map->num_stripes);
2165
2166	/*
2167	 * (stripe_index / sub_stripes) gives how many data stripes we need to
2168	 * skip.
2169	 */
2170	return btrfs_stripe_nr_to_offset(stripe_index / map->sub_stripes) +
2171	       bg->start;
2172}
2173
2174/* Get the mirror number for the stripe */
2175static int simple_stripe_mirror_num(struct btrfs_chunk_map *map, int stripe_index)
2176{
2177	ASSERT(map->type & (BTRFS_BLOCK_GROUP_RAID0 |
2178			    BTRFS_BLOCK_GROUP_RAID10));
2179	ASSERT(stripe_index < map->num_stripes);
2180
2181	/* For RAID0, it's fixed to 1, for RAID10 it's 0,1,0,1... */
2182	return stripe_index % map->sub_stripes + 1;
2183}
2184
2185static int scrub_simple_stripe(struct scrub_ctx *sctx,
2186			       struct btrfs_block_group *bg,
2187			       struct btrfs_chunk_map *map,
2188			       struct btrfs_device *device,
2189			       int stripe_index)
2190{
2191	const u64 logical_increment = simple_stripe_full_stripe_len(map);
2192	const u64 orig_logical = simple_stripe_get_logical(map, bg, stripe_index);
2193	const u64 orig_physical = map->stripes[stripe_index].physical;
2194	const int mirror_num = simple_stripe_mirror_num(map, stripe_index);
2195	u64 cur_logical = orig_logical;
2196	u64 cur_physical = orig_physical;
2197	int ret = 0;
2198
2199	while (cur_logical < bg->start + bg->length) {
2200		/*
2201		 * Inside each stripe, RAID0 is just SINGLE, and RAID10 is
2202		 * just RAID1, so we can reuse scrub_simple_mirror() to scrub
2203		 * this stripe.
2204		 */
2205		ret = scrub_simple_mirror(sctx, bg, map, cur_logical,
2206					  BTRFS_STRIPE_LEN, device, cur_physical,
2207					  mirror_num);
2208		if (ret)
2209			return ret;
2210		/* Skip to next stripe which belongs to the target device */
2211		cur_logical += logical_increment;
2212		/* For physical offset, we just go to next stripe */
2213		cur_physical += BTRFS_STRIPE_LEN;
2214	}
2215	return ret;
2216}
2217
2218static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
2219					   struct btrfs_block_group *bg,
2220					   struct btrfs_chunk_map *map,
2221					   struct btrfs_device *scrub_dev,
2222					   int stripe_index)
2223{
2224	struct btrfs_fs_info *fs_info = sctx->fs_info;
2225	const u64 profile = map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK;
2226	const u64 chunk_logical = bg->start;
2227	int ret;
2228	int ret2;
2229	u64 physical = map->stripes[stripe_index].physical;
2230	const u64 dev_stripe_len = btrfs_calc_stripe_length(map);
2231	const u64 physical_end = physical + dev_stripe_len;
2232	u64 logical;
2233	u64 logic_end;
2234	/* The logical increment after finishing one stripe */
2235	u64 increment;
2236	/* Offset inside the chunk */
2237	u64 offset;
2238	u64 stripe_logical;
2239	int stop_loop = 0;
2240
2241	/* Extent_path should be released by now. */
2242	ASSERT(sctx->extent_path.nodes[0] == NULL);
2243
2244	scrub_blocked_if_needed(fs_info);
2245
2246	if (sctx->is_dev_replace &&
2247	    btrfs_dev_is_sequential(sctx->wr_tgtdev, physical)) {
2248		mutex_lock(&sctx->wr_lock);
2249		sctx->write_pointer = physical;
2250		mutex_unlock(&sctx->wr_lock);
2251	}
2252
2253	/* Prepare the extra data stripes used by RAID56. */
2254	if (profile & BTRFS_BLOCK_GROUP_RAID56_MASK) {
2255		ASSERT(sctx->raid56_data_stripes == NULL);
2256
2257		sctx->raid56_data_stripes = kcalloc(nr_data_stripes(map),
2258						    sizeof(struct scrub_stripe),
2259						    GFP_KERNEL);
2260		if (!sctx->raid56_data_stripes) {
2261			ret = -ENOMEM;
2262			goto out;
2263		}
2264		for (int i = 0; i < nr_data_stripes(map); i++) {
2265			ret = init_scrub_stripe(fs_info,
2266						&sctx->raid56_data_stripes[i]);
2267			if (ret < 0)
2268				goto out;
2269			sctx->raid56_data_stripes[i].bg = bg;
2270			sctx->raid56_data_stripes[i].sctx = sctx;
2271		}
2272	}
2273	/*
2274	 * There used to be a big double loop to handle all profiles using the
2275	 * same routine, which grows larger and more gross over time.
2276	 *
2277	 * So here we handle each profile differently, so simpler profiles
2278	 * have simpler scrubbing function.
2279	 */
2280	if (!(profile & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10 |
2281			 BTRFS_BLOCK_GROUP_RAID56_MASK))) {
2282		/*
2283		 * Above check rules out all complex profile, the remaining
2284		 * profiles are SINGLE|DUP|RAID1|RAID1C*, which is simple
2285		 * mirrored duplication without stripe.
2286		 *
2287		 * Only @physical and @mirror_num needs to calculated using
2288		 * @stripe_index.
2289		 */
2290		ret = scrub_simple_mirror(sctx, bg, map, bg->start, bg->length,
2291				scrub_dev, map->stripes[stripe_index].physical,
2292				stripe_index + 1);
2293		offset = 0;
2294		goto out;
2295	}
2296	if (profile & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
2297		ret = scrub_simple_stripe(sctx, bg, map, scrub_dev, stripe_index);
2298		offset = btrfs_stripe_nr_to_offset(stripe_index / map->sub_stripes);
2299		goto out;
2300	}
2301
2302	/* Only RAID56 goes through the old code */
2303	ASSERT(map->type & BTRFS_BLOCK_GROUP_RAID56_MASK);
2304	ret = 0;
2305
2306	/* Calculate the logical end of the stripe */
2307	get_raid56_logic_offset(physical_end, stripe_index,
2308				map, &logic_end, NULL);
2309	logic_end += chunk_logical;
2310
2311	/* Initialize @offset in case we need to go to out: label */
2312	get_raid56_logic_offset(physical, stripe_index, map, &offset, NULL);
2313	increment = btrfs_stripe_nr_to_offset(nr_data_stripes(map));
2314
2315	/*
2316	 * Due to the rotation, for RAID56 it's better to iterate each stripe
2317	 * using their physical offset.
2318	 */
2319	while (physical < physical_end) {
2320		ret = get_raid56_logic_offset(physical, stripe_index, map,
2321					      &logical, &stripe_logical);
2322		logical += chunk_logical;
2323		if (ret) {
2324			/* it is parity strip */
2325			stripe_logical += chunk_logical;
2326			ret = scrub_raid56_parity_stripe(sctx, scrub_dev, bg,
2327							 map, stripe_logical);
2328			if (ret)
2329				goto out;
2330			goto next;
2331		}
2332
2333		/*
2334		 * Now we're at a data stripe, scrub each extents in the range.
2335		 *
2336		 * At this stage, if we ignore the repair part, inside each data
2337		 * stripe it is no different than SINGLE profile.
2338		 * We can reuse scrub_simple_mirror() here, as the repair part
2339		 * is still based on @mirror_num.
2340		 */
2341		ret = scrub_simple_mirror(sctx, bg, map, logical, BTRFS_STRIPE_LEN,
2342					  scrub_dev, physical, 1);
2343		if (ret < 0)
2344			goto out;
2345next:
2346		logical += increment;
2347		physical += BTRFS_STRIPE_LEN;
2348		spin_lock(&sctx->stat_lock);
2349		if (stop_loop)
2350			sctx->stat.last_physical =
2351				map->stripes[stripe_index].physical + dev_stripe_len;
2352		else
2353			sctx->stat.last_physical = physical;
2354		spin_unlock(&sctx->stat_lock);
2355		if (stop_loop)
2356			break;
2357	}
2358out:
2359	ret2 = flush_scrub_stripes(sctx);
2360	if (!ret)
2361		ret = ret2;
2362	btrfs_release_path(&sctx->extent_path);
2363	btrfs_release_path(&sctx->csum_path);
2364
2365	if (sctx->raid56_data_stripes) {
2366		for (int i = 0; i < nr_data_stripes(map); i++)
2367			release_scrub_stripe(&sctx->raid56_data_stripes[i]);
2368		kfree(sctx->raid56_data_stripes);
2369		sctx->raid56_data_stripes = NULL;
2370	}
2371
2372	if (sctx->is_dev_replace && ret >= 0) {
2373		int ret2;
2374
2375		ret2 = sync_write_pointer_for_zoned(sctx,
2376				chunk_logical + offset,
2377				map->stripes[stripe_index].physical,
2378				physical_end);
2379		if (ret2)
2380			ret = ret2;
2381	}
2382
2383	return ret < 0 ? ret : 0;
2384}
2385
2386static noinline_for_stack int scrub_chunk(struct scrub_ctx *sctx,
2387					  struct btrfs_block_group *bg,
2388					  struct btrfs_device *scrub_dev,
2389					  u64 dev_offset,
2390					  u64 dev_extent_len)
2391{
2392	struct btrfs_fs_info *fs_info = sctx->fs_info;
2393	struct btrfs_chunk_map *map;
2394	int i;
2395	int ret = 0;
2396
2397	map = btrfs_find_chunk_map(fs_info, bg->start, bg->length);
2398	if (!map) {
2399		/*
2400		 * Might have been an unused block group deleted by the cleaner
2401		 * kthread or relocation.
2402		 */
2403		spin_lock(&bg->lock);
2404		if (!test_bit(BLOCK_GROUP_FLAG_REMOVED, &bg->runtime_flags))
2405			ret = -EINVAL;
2406		spin_unlock(&bg->lock);
2407
2408		return ret;
2409	}
2410	if (map->start != bg->start)
2411		goto out;
2412	if (map->chunk_len < dev_extent_len)
2413		goto out;
2414
2415	for (i = 0; i < map->num_stripes; ++i) {
2416		if (map->stripes[i].dev->bdev == scrub_dev->bdev &&
2417		    map->stripes[i].physical == dev_offset) {
2418			ret = scrub_stripe(sctx, bg, map, scrub_dev, i);
2419			if (ret)
2420				goto out;
2421		}
2422	}
2423out:
2424	btrfs_free_chunk_map(map);
2425
2426	return ret;
2427}
2428
2429static int finish_extent_writes_for_zoned(struct btrfs_root *root,
2430					  struct btrfs_block_group *cache)
2431{
2432	struct btrfs_fs_info *fs_info = cache->fs_info;
2433	struct btrfs_trans_handle *trans;
2434
2435	if (!btrfs_is_zoned(fs_info))
2436		return 0;
2437
2438	btrfs_wait_block_group_reservations(cache);
2439	btrfs_wait_nocow_writers(cache);
2440	btrfs_wait_ordered_roots(fs_info, U64_MAX, cache->start, cache->length);
2441
2442	trans = btrfs_join_transaction(root);
2443	if (IS_ERR(trans))
2444		return PTR_ERR(trans);
2445	return btrfs_commit_transaction(trans);
2446}
2447
2448static noinline_for_stack
2449int scrub_enumerate_chunks(struct scrub_ctx *sctx,
2450			   struct btrfs_device *scrub_dev, u64 start, u64 end)
2451{
2452	struct btrfs_dev_extent *dev_extent = NULL;
2453	struct btrfs_path *path;
2454	struct btrfs_fs_info *fs_info = sctx->fs_info;
2455	struct btrfs_root *root = fs_info->dev_root;
2456	u64 chunk_offset;
2457	int ret = 0;
2458	int ro_set;
2459	int slot;
2460	struct extent_buffer *l;
2461	struct btrfs_key key;
2462	struct btrfs_key found_key;
2463	struct btrfs_block_group *cache;
2464	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
2465
2466	path = btrfs_alloc_path();
2467	if (!path)
2468		return -ENOMEM;
2469
2470	path->reada = READA_FORWARD;
2471	path->search_commit_root = 1;
2472	path->skip_locking = 1;
2473
2474	key.objectid = scrub_dev->devid;
2475	key.offset = 0ull;
2476	key.type = BTRFS_DEV_EXTENT_KEY;
2477
2478	while (1) {
2479		u64 dev_extent_len;
2480
2481		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2482		if (ret < 0)
2483			break;
2484		if (ret > 0) {
2485			if (path->slots[0] >=
2486			    btrfs_header_nritems(path->nodes[0])) {
2487				ret = btrfs_next_leaf(root, path);
2488				if (ret < 0)
2489					break;
2490				if (ret > 0) {
2491					ret = 0;
2492					break;
2493				}
2494			} else {
2495				ret = 0;
2496			}
2497		}
2498
2499		l = path->nodes[0];
2500		slot = path->slots[0];
2501
2502		btrfs_item_key_to_cpu(l, &found_key, slot);
2503
2504		if (found_key.objectid != scrub_dev->devid)
2505			break;
2506
2507		if (found_key.type != BTRFS_DEV_EXTENT_KEY)
2508			break;
2509
2510		if (found_key.offset >= end)
2511			break;
2512
2513		if (found_key.offset < key.offset)
2514			break;
2515
2516		dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
2517		dev_extent_len = btrfs_dev_extent_length(l, dev_extent);
2518
2519		if (found_key.offset + dev_extent_len <= start)
2520			goto skip;
2521
2522		chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
2523
2524		/*
2525		 * get a reference on the corresponding block group to prevent
2526		 * the chunk from going away while we scrub it
2527		 */
2528		cache = btrfs_lookup_block_group(fs_info, chunk_offset);
2529
2530		/* some chunks are removed but not committed to disk yet,
2531		 * continue scrubbing */
2532		if (!cache)
2533			goto skip;
2534
2535		ASSERT(cache->start <= chunk_offset);
2536		/*
2537		 * We are using the commit root to search for device extents, so
2538		 * that means we could have found a device extent item from a
2539		 * block group that was deleted in the current transaction. The
2540		 * logical start offset of the deleted block group, stored at
2541		 * @chunk_offset, might be part of the logical address range of
2542		 * a new block group (which uses different physical extents).
2543		 * In this case btrfs_lookup_block_group() has returned the new
2544		 * block group, and its start address is less than @chunk_offset.
2545		 *
2546		 * We skip such new block groups, because it's pointless to
2547		 * process them, as we won't find their extents because we search
2548		 * for them using the commit root of the extent tree. For a device
2549		 * replace it's also fine to skip it, we won't miss copying them
2550		 * to the target device because we have the write duplication
2551		 * setup through the regular write path (by btrfs_map_block()),
2552		 * and we have committed a transaction when we started the device
2553		 * replace, right after setting up the device replace state.
2554		 */
2555		if (cache->start < chunk_offset) {
2556			btrfs_put_block_group(cache);
2557			goto skip;
2558		}
2559
2560		if (sctx->is_dev_replace && btrfs_is_zoned(fs_info)) {
2561			if (!test_bit(BLOCK_GROUP_FLAG_TO_COPY, &cache->runtime_flags)) {
2562				btrfs_put_block_group(cache);
2563				goto skip;
2564			}
2565		}
2566
2567		/*
2568		 * Make sure that while we are scrubbing the corresponding block
2569		 * group doesn't get its logical address and its device extents
2570		 * reused for another block group, which can possibly be of a
2571		 * different type and different profile. We do this to prevent
2572		 * false error detections and crashes due to bogus attempts to
2573		 * repair extents.
2574		 */
2575		spin_lock(&cache->lock);
2576		if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &cache->runtime_flags)) {
2577			spin_unlock(&cache->lock);
2578			btrfs_put_block_group(cache);
2579			goto skip;
2580		}
2581		btrfs_freeze_block_group(cache);
2582		spin_unlock(&cache->lock);
2583
2584		/*
2585		 * we need call btrfs_inc_block_group_ro() with scrubs_paused,
2586		 * to avoid deadlock caused by:
2587		 * btrfs_inc_block_group_ro()
2588		 * -> btrfs_wait_for_commit()
2589		 * -> btrfs_commit_transaction()
2590		 * -> btrfs_scrub_pause()
2591		 */
2592		scrub_pause_on(fs_info);
2593
2594		/*
2595		 * Don't do chunk preallocation for scrub.
2596		 *
2597		 * This is especially important for SYSTEM bgs, or we can hit
2598		 * -EFBIG from btrfs_finish_chunk_alloc() like:
2599		 * 1. The only SYSTEM bg is marked RO.
2600		 *    Since SYSTEM bg is small, that's pretty common.
2601		 * 2. New SYSTEM bg will be allocated
2602		 *    Due to regular version will allocate new chunk.
2603		 * 3. New SYSTEM bg is empty and will get cleaned up
2604		 *    Before cleanup really happens, it's marked RO again.
2605		 * 4. Empty SYSTEM bg get scrubbed
2606		 *    We go back to 2.
2607		 *
2608		 * This can easily boost the amount of SYSTEM chunks if cleaner
2609		 * thread can't be triggered fast enough, and use up all space
2610		 * of btrfs_super_block::sys_chunk_array
2611		 *
2612		 * While for dev replace, we need to try our best to mark block
2613		 * group RO, to prevent race between:
2614		 * - Write duplication
2615		 *   Contains latest data
2616		 * - Scrub copy
2617		 *   Contains data from commit tree
2618		 *
2619		 * If target block group is not marked RO, nocow writes can
2620		 * be overwritten by scrub copy, causing data corruption.
2621		 * So for dev-replace, it's not allowed to continue if a block
2622		 * group is not RO.
2623		 */
2624		ret = btrfs_inc_block_group_ro(cache, sctx->is_dev_replace);
2625		if (!ret && sctx->is_dev_replace) {
2626			ret = finish_extent_writes_for_zoned(root, cache);
2627			if (ret) {
2628				btrfs_dec_block_group_ro(cache);
2629				scrub_pause_off(fs_info);
2630				btrfs_put_block_group(cache);
2631				break;
2632			}
2633		}
2634
2635		if (ret == 0) {
2636			ro_set = 1;
2637		} else if (ret == -ENOSPC && !sctx->is_dev_replace &&
2638			   !(cache->flags & BTRFS_BLOCK_GROUP_RAID56_MASK)) {
2639			/*
2640			 * btrfs_inc_block_group_ro return -ENOSPC when it
2641			 * failed in creating new chunk for metadata.
2642			 * It is not a problem for scrub, because
2643			 * metadata are always cowed, and our scrub paused
2644			 * commit_transactions.
2645			 *
2646			 * For RAID56 chunks, we have to mark them read-only
2647			 * for scrub, as later we would use our own cache
2648			 * out of RAID56 realm.
2649			 * Thus we want the RAID56 bg to be marked RO to
2650			 * prevent RMW from screwing up out cache.
2651			 */
2652			ro_set = 0;
2653		} else if (ret == -ETXTBSY) {
2654			btrfs_warn(fs_info,
2655		   "skipping scrub of block group %llu due to active swapfile",
2656				   cache->start);
2657			scrub_pause_off(fs_info);
2658			ret = 0;
2659			goto skip_unfreeze;
2660		} else {
2661			btrfs_warn(fs_info,
2662				   "failed setting block group ro: %d", ret);
2663			btrfs_unfreeze_block_group(cache);
2664			btrfs_put_block_group(cache);
2665			scrub_pause_off(fs_info);
2666			break;
2667		}
2668
2669		/*
2670		 * Now the target block is marked RO, wait for nocow writes to
2671		 * finish before dev-replace.
2672		 * COW is fine, as COW never overwrites extents in commit tree.
2673		 */
2674		if (sctx->is_dev_replace) {
2675			btrfs_wait_nocow_writers(cache);
2676			btrfs_wait_ordered_roots(fs_info, U64_MAX, cache->start,
2677					cache->length);
2678		}
2679
2680		scrub_pause_off(fs_info);
2681		down_write(&dev_replace->rwsem);
2682		dev_replace->cursor_right = found_key.offset + dev_extent_len;
2683		dev_replace->cursor_left = found_key.offset;
2684		dev_replace->item_needs_writeback = 1;
2685		up_write(&dev_replace->rwsem);
2686
2687		ret = scrub_chunk(sctx, cache, scrub_dev, found_key.offset,
2688				  dev_extent_len);
2689		if (sctx->is_dev_replace &&
2690		    !btrfs_finish_block_group_to_copy(dev_replace->srcdev,
2691						      cache, found_key.offset))
2692			ro_set = 0;
2693
2694		down_write(&dev_replace->rwsem);
2695		dev_replace->cursor_left = dev_replace->cursor_right;
2696		dev_replace->item_needs_writeback = 1;
2697		up_write(&dev_replace->rwsem);
2698
2699		if (ro_set)
2700			btrfs_dec_block_group_ro(cache);
2701
2702		/*
2703		 * We might have prevented the cleaner kthread from deleting
2704		 * this block group if it was already unused because we raced
2705		 * and set it to RO mode first. So add it back to the unused
2706		 * list, otherwise it might not ever be deleted unless a manual
2707		 * balance is triggered or it becomes used and unused again.
2708		 */
2709		spin_lock(&cache->lock);
2710		if (!test_bit(BLOCK_GROUP_FLAG_REMOVED, &cache->runtime_flags) &&
2711		    !cache->ro && cache->reserved == 0 && cache->used == 0) {
2712			spin_unlock(&cache->lock);
2713			if (btrfs_test_opt(fs_info, DISCARD_ASYNC))
2714				btrfs_discard_queue_work(&fs_info->discard_ctl,
2715							 cache);
2716			else
2717				btrfs_mark_bg_unused(cache);
2718		} else {
2719			spin_unlock(&cache->lock);
2720		}
2721skip_unfreeze:
2722		btrfs_unfreeze_block_group(cache);
2723		btrfs_put_block_group(cache);
2724		if (ret)
2725			break;
2726		if (sctx->is_dev_replace &&
2727		    atomic64_read(&dev_replace->num_write_errors) > 0) {
2728			ret = -EIO;
2729			break;
2730		}
2731		if (sctx->stat.malloc_errors > 0) {
2732			ret = -ENOMEM;
2733			break;
2734		}
2735skip:
2736		key.offset = found_key.offset + dev_extent_len;
2737		btrfs_release_path(path);
2738	}
2739
2740	btrfs_free_path(path);
2741
2742	return ret;
2743}
2744
2745static int scrub_one_super(struct scrub_ctx *sctx, struct btrfs_device *dev,
2746			   struct page *page, u64 physical, u64 generation)
2747{
2748	struct btrfs_fs_info *fs_info = sctx->fs_info;
2749	struct bio_vec bvec;
2750	struct bio bio;
2751	struct btrfs_super_block *sb = page_address(page);
2752	int ret;
2753
2754	bio_init(&bio, dev->bdev, &bvec, 1, REQ_OP_READ);
2755	bio.bi_iter.bi_sector = physical >> SECTOR_SHIFT;
2756	__bio_add_page(&bio, page, BTRFS_SUPER_INFO_SIZE, 0);
2757	ret = submit_bio_wait(&bio);
2758	bio_uninit(&bio);
2759
2760	if (ret < 0)
2761		return ret;
2762	ret = btrfs_check_super_csum(fs_info, sb);
2763	if (ret != 0) {
2764		btrfs_err_rl(fs_info,
2765			"super block at physical %llu devid %llu has bad csum",
2766			physical, dev->devid);
2767		return -EIO;
2768	}
2769	if (btrfs_super_generation(sb) != generation) {
2770		btrfs_err_rl(fs_info,
2771"super block at physical %llu devid %llu has bad generation %llu expect %llu",
2772			     physical, dev->devid,
2773			     btrfs_super_generation(sb), generation);
2774		return -EUCLEAN;
2775	}
2776
2777	return btrfs_validate_super(fs_info, sb, -1);
2778}
2779
2780static noinline_for_stack int scrub_supers(struct scrub_ctx *sctx,
2781					   struct btrfs_device *scrub_dev)
2782{
2783	int	i;
2784	u64	bytenr;
2785	u64	gen;
2786	int ret = 0;
2787	struct page *page;
2788	struct btrfs_fs_info *fs_info = sctx->fs_info;
2789
2790	if (BTRFS_FS_ERROR(fs_info))
2791		return -EROFS;
2792
2793	page = alloc_page(GFP_KERNEL);
2794	if (!page) {
2795		spin_lock(&sctx->stat_lock);
2796		sctx->stat.malloc_errors++;
2797		spin_unlock(&sctx->stat_lock);
2798		return -ENOMEM;
2799	}
2800
2801	/* Seed devices of a new filesystem has their own generation. */
2802	if (scrub_dev->fs_devices != fs_info->fs_devices)
2803		gen = scrub_dev->generation;
2804	else
2805		gen = btrfs_get_last_trans_committed(fs_info);
2806
2807	for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
2808		bytenr = btrfs_sb_offset(i);
 
 
 
 
 
 
 
 
 
 
2809		if (bytenr + BTRFS_SUPER_INFO_SIZE >
2810		    scrub_dev->commit_total_bytes)
2811			break;
2812		if (!btrfs_check_super_location(scrub_dev, bytenr))
2813			continue;
2814
2815		ret = scrub_one_super(sctx, scrub_dev, page, bytenr, gen);
2816		if (ret) {
2817			spin_lock(&sctx->stat_lock);
2818			sctx->stat.super_errors++;
2819			spin_unlock(&sctx->stat_lock);
2820		}
2821	}
2822	__free_page(page);
2823	return 0;
2824}
2825
2826static void scrub_workers_put(struct btrfs_fs_info *fs_info)
2827{
2828	if (refcount_dec_and_mutex_lock(&fs_info->scrub_workers_refcnt,
2829					&fs_info->scrub_lock)) {
2830		struct workqueue_struct *scrub_workers = fs_info->scrub_workers;
2831
2832		fs_info->scrub_workers = NULL;
2833		mutex_unlock(&fs_info->scrub_lock);
2834
2835		if (scrub_workers)
2836			destroy_workqueue(scrub_workers);
2837	}
2838}
2839
2840/*
2841 * get a reference count on fs_info->scrub_workers. start worker if necessary
2842 */
2843static noinline_for_stack int scrub_workers_get(struct btrfs_fs_info *fs_info)
2844{
2845	struct workqueue_struct *scrub_workers = NULL;
2846	unsigned int flags = WQ_FREEZABLE | WQ_UNBOUND;
2847	int max_active = fs_info->thread_pool_size;
2848	int ret = -ENOMEM;
2849
2850	if (refcount_inc_not_zero(&fs_info->scrub_workers_refcnt))
2851		return 0;
2852
2853	scrub_workers = alloc_workqueue("btrfs-scrub", flags, max_active);
2854	if (!scrub_workers)
2855		return -ENOMEM;
2856
2857	mutex_lock(&fs_info->scrub_lock);
2858	if (refcount_read(&fs_info->scrub_workers_refcnt) == 0) {
2859		ASSERT(fs_info->scrub_workers == NULL);
2860		fs_info->scrub_workers = scrub_workers;
2861		refcount_set(&fs_info->scrub_workers_refcnt, 1);
2862		mutex_unlock(&fs_info->scrub_lock);
2863		return 0;
2864	}
2865	/* Other thread raced in and created the workers for us */
2866	refcount_inc(&fs_info->scrub_workers_refcnt);
2867	mutex_unlock(&fs_info->scrub_lock);
2868
2869	ret = 0;
2870
2871	destroy_workqueue(scrub_workers);
2872	return ret;
2873}
2874
2875int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
2876		    u64 end, struct btrfs_scrub_progress *progress,
2877		    int readonly, int is_dev_replace)
2878{
2879	struct btrfs_dev_lookup_args args = { .devid = devid };
2880	struct scrub_ctx *sctx;
2881	int ret;
2882	struct btrfs_device *dev;
2883	unsigned int nofs_flag;
2884	bool need_commit = false;
2885
2886	if (btrfs_fs_closing(fs_info))
2887		return -EAGAIN;
2888
2889	/* At mount time we have ensured nodesize is in the range of [4K, 64K]. */
2890	ASSERT(fs_info->nodesize <= BTRFS_STRIPE_LEN);
2891
2892	/*
2893	 * SCRUB_MAX_SECTORS_PER_BLOCK is calculated using the largest possible
2894	 * value (max nodesize / min sectorsize), thus nodesize should always
2895	 * be fine.
2896	 */
2897	ASSERT(fs_info->nodesize <=
2898	       SCRUB_MAX_SECTORS_PER_BLOCK << fs_info->sectorsize_bits);
2899
2900	/* Allocate outside of device_list_mutex */
2901	sctx = scrub_setup_ctx(fs_info, is_dev_replace);
2902	if (IS_ERR(sctx))
2903		return PTR_ERR(sctx);
2904
2905	ret = scrub_workers_get(fs_info);
2906	if (ret)
2907		goto out_free_ctx;
2908
2909	mutex_lock(&fs_info->fs_devices->device_list_mutex);
2910	dev = btrfs_find_device(fs_info->fs_devices, &args);
2911	if (!dev || (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state) &&
2912		     !is_dev_replace)) {
2913		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2914		ret = -ENODEV;
2915		goto out;
2916	}
2917
2918	if (!is_dev_replace && !readonly &&
2919	    !test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state)) {
2920		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2921		btrfs_err_in_rcu(fs_info,
2922			"scrub on devid %llu: filesystem on %s is not writable",
2923				 devid, btrfs_dev_name(dev));
2924		ret = -EROFS;
2925		goto out;
2926	}
2927
2928	mutex_lock(&fs_info->scrub_lock);
2929	if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &dev->dev_state) ||
2930	    test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &dev->dev_state)) {
2931		mutex_unlock(&fs_info->scrub_lock);
2932		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2933		ret = -EIO;
2934		goto out;
2935	}
2936
2937	down_read(&fs_info->dev_replace.rwsem);
2938	if (dev->scrub_ctx ||
2939	    (!is_dev_replace &&
2940	     btrfs_dev_replace_is_ongoing(&fs_info->dev_replace))) {
2941		up_read(&fs_info->dev_replace.rwsem);
2942		mutex_unlock(&fs_info->scrub_lock);
2943		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2944		ret = -EINPROGRESS;
2945		goto out;
2946	}
2947	up_read(&fs_info->dev_replace.rwsem);
2948
2949	sctx->readonly = readonly;
2950	dev->scrub_ctx = sctx;
2951	mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2952
2953	/*
2954	 * checking @scrub_pause_req here, we can avoid
2955	 * race between committing transaction and scrubbing.
2956	 */
2957	__scrub_blocked_if_needed(fs_info);
2958	atomic_inc(&fs_info->scrubs_running);
2959	mutex_unlock(&fs_info->scrub_lock);
2960
2961	/*
2962	 * In order to avoid deadlock with reclaim when there is a transaction
2963	 * trying to pause scrub, make sure we use GFP_NOFS for all the
2964	 * allocations done at btrfs_scrub_sectors() and scrub_sectors_for_parity()
2965	 * invoked by our callees. The pausing request is done when the
2966	 * transaction commit starts, and it blocks the transaction until scrub
2967	 * is paused (done at specific points at scrub_stripe() or right above
2968	 * before incrementing fs_info->scrubs_running).
2969	 */
2970	nofs_flag = memalloc_nofs_save();
2971	if (!is_dev_replace) {
2972		u64 old_super_errors;
2973
2974		spin_lock(&sctx->stat_lock);
2975		old_super_errors = sctx->stat.super_errors;
2976		spin_unlock(&sctx->stat_lock);
2977
2978		btrfs_info(fs_info, "scrub: started on devid %llu", devid);
2979		/*
2980		 * by holding device list mutex, we can
2981		 * kick off writing super in log tree sync.
2982		 */
2983		mutex_lock(&fs_info->fs_devices->device_list_mutex);
2984		ret = scrub_supers(sctx, dev);
2985		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2986
2987		spin_lock(&sctx->stat_lock);
2988		/*
2989		 * Super block errors found, but we can not commit transaction
2990		 * at current context, since btrfs_commit_transaction() needs
2991		 * to pause the current running scrub (hold by ourselves).
2992		 */
2993		if (sctx->stat.super_errors > old_super_errors && !sctx->readonly)
2994			need_commit = true;
2995		spin_unlock(&sctx->stat_lock);
2996	}
2997
2998	if (!ret)
2999		ret = scrub_enumerate_chunks(sctx, dev, start, end);
3000	memalloc_nofs_restore(nofs_flag);
3001
3002	atomic_dec(&fs_info->scrubs_running);
3003	wake_up(&fs_info->scrub_pause_wait);
3004
3005	if (progress)
3006		memcpy(progress, &sctx->stat, sizeof(*progress));
3007
3008	if (!is_dev_replace)
3009		btrfs_info(fs_info, "scrub: %s on devid %llu with status: %d",
3010			ret ? "not finished" : "finished", devid, ret);
3011
3012	mutex_lock(&fs_info->scrub_lock);
3013	dev->scrub_ctx = NULL;
3014	mutex_unlock(&fs_info->scrub_lock);
3015
3016	scrub_workers_put(fs_info);
3017	scrub_put_ctx(sctx);
3018
3019	/*
3020	 * We found some super block errors before, now try to force a
3021	 * transaction commit, as scrub has finished.
3022	 */
3023	if (need_commit) {
3024		struct btrfs_trans_handle *trans;
3025
3026		trans = btrfs_start_transaction(fs_info->tree_root, 0);
3027		if (IS_ERR(trans)) {
3028			ret = PTR_ERR(trans);
3029			btrfs_err(fs_info,
3030	"scrub: failed to start transaction to fix super block errors: %d", ret);
3031			return ret;
3032		}
3033		ret = btrfs_commit_transaction(trans);
3034		if (ret < 0)
3035			btrfs_err(fs_info,
3036	"scrub: failed to commit transaction to fix super block errors: %d", ret);
3037	}
3038	return ret;
3039out:
3040	scrub_workers_put(fs_info);
3041out_free_ctx:
3042	scrub_free_ctx(sctx);
3043
3044	return ret;
3045}
3046
3047void btrfs_scrub_pause(struct btrfs_fs_info *fs_info)
3048{
3049	mutex_lock(&fs_info->scrub_lock);
3050	atomic_inc(&fs_info->scrub_pause_req);
3051	while (atomic_read(&fs_info->scrubs_paused) !=
3052	       atomic_read(&fs_info->scrubs_running)) {
3053		mutex_unlock(&fs_info->scrub_lock);
3054		wait_event(fs_info->scrub_pause_wait,
3055			   atomic_read(&fs_info->scrubs_paused) ==
3056			   atomic_read(&fs_info->scrubs_running));
3057		mutex_lock(&fs_info->scrub_lock);
3058	}
3059	mutex_unlock(&fs_info->scrub_lock);
3060}
3061
3062void btrfs_scrub_continue(struct btrfs_fs_info *fs_info)
3063{
3064	atomic_dec(&fs_info->scrub_pause_req);
3065	wake_up(&fs_info->scrub_pause_wait);
3066}
3067
3068int btrfs_scrub_cancel(struct btrfs_fs_info *fs_info)
3069{
3070	mutex_lock(&fs_info->scrub_lock);
3071	if (!atomic_read(&fs_info->scrubs_running)) {
3072		mutex_unlock(&fs_info->scrub_lock);
3073		return -ENOTCONN;
3074	}
3075
3076	atomic_inc(&fs_info->scrub_cancel_req);
3077	while (atomic_read(&fs_info->scrubs_running)) {
3078		mutex_unlock(&fs_info->scrub_lock);
3079		wait_event(fs_info->scrub_pause_wait,
3080			   atomic_read(&fs_info->scrubs_running) == 0);
3081		mutex_lock(&fs_info->scrub_lock);
3082	}
3083	atomic_dec(&fs_info->scrub_cancel_req);
3084	mutex_unlock(&fs_info->scrub_lock);
3085
3086	return 0;
3087}
3088
3089int btrfs_scrub_cancel_dev(struct btrfs_device *dev)
3090{
3091	struct btrfs_fs_info *fs_info = dev->fs_info;
3092	struct scrub_ctx *sctx;
3093
3094	mutex_lock(&fs_info->scrub_lock);
3095	sctx = dev->scrub_ctx;
3096	if (!sctx) {
3097		mutex_unlock(&fs_info->scrub_lock);
3098		return -ENOTCONN;
3099	}
3100	atomic_inc(&sctx->cancel_req);
3101	while (dev->scrub_ctx) {
3102		mutex_unlock(&fs_info->scrub_lock);
3103		wait_event(fs_info->scrub_pause_wait,
3104			   dev->scrub_ctx == NULL);
3105		mutex_lock(&fs_info->scrub_lock);
3106	}
3107	mutex_unlock(&fs_info->scrub_lock);
3108
3109	return 0;
3110}
3111
3112int btrfs_scrub_progress(struct btrfs_fs_info *fs_info, u64 devid,
3113			 struct btrfs_scrub_progress *progress)
3114{
3115	struct btrfs_dev_lookup_args args = { .devid = devid };
3116	struct btrfs_device *dev;
3117	struct scrub_ctx *sctx = NULL;
3118
3119	mutex_lock(&fs_info->fs_devices->device_list_mutex);
3120	dev = btrfs_find_device(fs_info->fs_devices, &args);
3121	if (dev)
3122		sctx = dev->scrub_ctx;
3123	if (sctx)
3124		memcpy(progress, &sctx->stat, sizeof(*progress));
3125	mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3126
3127	return dev ? (sctx ? 0 : -ENOTCONN) : -ENODEV;
3128}
v6.9.4
   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
  41struct 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. */
  68struct 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
  88enum 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 */
 108struct 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
 185struct 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
 222struct 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
 231static 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
 249static 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;
 279error:
 280	release_scrub_stripe(stripe);
 281	return -ENOMEM;
 282}
 283
 284static void wait_scrub_stripe_io(struct scrub_stripe *stripe)
 285{
 286	wait_event(stripe->io_wait, atomic_read(&stripe->pending_io) == 0);
 287}
 288
 289static void scrub_put_ctx(struct scrub_ctx *sctx);
 290
 291static 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
 301static 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
 307static 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
 317static 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
 323static 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
 336static void scrub_put_ctx(struct scrub_ctx *sctx)
 337{
 338	if (refcount_dec_and_test(&sctx->refs))
 339		scrub_free_ctx(sctx);
 340}
 341
 342static 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
 383nomem:
 384	scrub_free_ctx(sctx);
 385	return ERR_PTR(-ENOMEM);
 386}
 387
 388static 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
 466err:
 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
 478static 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
 556out:
 557	btrfs_free_path(path);
 558}
 559
 560static 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
 582static 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
 590static 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
 598static 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
 689static 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. */
 751static 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
 764static 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 */
 783static 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
 811static 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
 817static 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
 866static 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
 911skip:
 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
 992static 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 */
1008static 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	}
1077out:
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
1098static 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
1126static 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
1152static 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 */
1194static 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 */
1232static 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 */
1291static 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 */
1333static 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 */
1371static 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	 */
1413search_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;
1427next:
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
1439static 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
1458static 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
1482static 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
1504static 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 */
1524static 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);
1632out:
1633	return ret;
1634}
1635
1636static 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
1651static 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			bbio = btrfs_bio_alloc(stripe->nr_sectors, REQ_OP_READ,
1692					       fs_info, scrub_read_endio, stripe);
1693			bbio->bio.bi_iter.bi_sector = logical >> SECTOR_SHIFT;
1694
1695			io_stripe.is_scrub = true;
1696			err = btrfs_map_block(fs_info, BTRFS_MAP_READ, logical,
1697					      &stripe_len, &bioc, &io_stripe,
1698					      &mirror);
1699			btrfs_put_bioc(bioc);
1700			if (err) {
1701				btrfs_bio_end_io(bbio,
1702						 errno_to_blk_status(err));
1703				return;
1704			}
1705		}
1706
1707		__bio_add_page(&bbio->bio, page, fs_info->sectorsize, pgoff);
1708	}
1709
1710	if (bbio) {
1711		ASSERT(bbio->bio.bi_iter.bi_size);
1712		atomic_inc(&stripe->pending_io);
1713		btrfs_submit_bio(bbio, mirror);
1714	}
1715
1716	if (atomic_dec_and_test(&stripe->pending_io)) {
1717		wake_up(&stripe->io_wait);
1718		INIT_WORK(&stripe->work, scrub_stripe_read_repair_worker);
1719		queue_work(stripe->bg->fs_info->scrub_workers, &stripe->work);
1720	}
1721}
1722
1723static void scrub_submit_initial_read(struct scrub_ctx *sctx,
1724				      struct scrub_stripe *stripe)
1725{
1726	struct btrfs_fs_info *fs_info = sctx->fs_info;
1727	struct btrfs_bio *bbio;
1728	unsigned int nr_sectors = min(BTRFS_STRIPE_LEN, stripe->bg->start +
1729				      stripe->bg->length - stripe->logical) >>
1730				  fs_info->sectorsize_bits;
1731	int mirror = stripe->mirror_num;
1732
1733	ASSERT(stripe->bg);
1734	ASSERT(stripe->mirror_num > 0);
1735	ASSERT(test_bit(SCRUB_STRIPE_FLAG_INITIALIZED, &stripe->state));
1736
1737	if (btrfs_need_stripe_tree_update(fs_info, stripe->bg->flags)) {
1738		scrub_submit_extent_sector_read(sctx, stripe);
1739		return;
1740	}
1741
1742	bbio = btrfs_bio_alloc(SCRUB_STRIPE_PAGES, REQ_OP_READ, fs_info,
1743			       scrub_read_endio, stripe);
1744
1745	bbio->bio.bi_iter.bi_sector = stripe->logical >> SECTOR_SHIFT;
1746	/* Read the whole range inside the chunk boundary. */
1747	for (unsigned int cur = 0; cur < nr_sectors; cur++) {
1748		struct page *page = scrub_stripe_get_page(stripe, cur);
1749		unsigned int pgoff = scrub_stripe_get_page_offset(stripe, cur);
1750		int ret;
1751
1752		ret = bio_add_page(&bbio->bio, page, fs_info->sectorsize, pgoff);
1753		/* We should have allocated enough bio vectors. */
1754		ASSERT(ret == fs_info->sectorsize);
1755	}
1756	atomic_inc(&stripe->pending_io);
1757
1758	/*
1759	 * For dev-replace, either user asks to avoid the source dev, or
1760	 * the device is missing, we try the next mirror instead.
1761	 */
1762	if (sctx->is_dev_replace &&
1763	    (fs_info->dev_replace.cont_reading_from_srcdev_mode ==
1764	     BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_AVOID ||
1765	     !stripe->dev->bdev)) {
1766		int num_copies = btrfs_num_copies(fs_info, stripe->bg->start,
1767						  stripe->bg->length);
1768
1769		mirror = calc_next_mirror(mirror, num_copies);
1770	}
1771	btrfs_submit_bio(bbio, mirror);
1772}
1773
1774static bool stripe_has_metadata_error(struct scrub_stripe *stripe)
1775{
1776	int i;
1777
1778	for_each_set_bit(i, &stripe->error_bitmap, stripe->nr_sectors) {
1779		if (stripe->sectors[i].is_metadata) {
1780			struct btrfs_fs_info *fs_info = stripe->bg->fs_info;
1781
1782			btrfs_err(fs_info,
1783			"stripe %llu has unrepaired metadata sector at %llu",
1784				  stripe->logical,
1785				  stripe->logical + (i << fs_info->sectorsize_bits));
1786			return true;
1787		}
1788	}
1789	return false;
1790}
1791
1792static void submit_initial_group_read(struct scrub_ctx *sctx,
1793				      unsigned int first_slot,
1794				      unsigned int nr_stripes)
1795{
1796	struct blk_plug plug;
1797
1798	ASSERT(first_slot < SCRUB_TOTAL_STRIPES);
1799	ASSERT(first_slot + nr_stripes <= SCRUB_TOTAL_STRIPES);
1800
1801	scrub_throttle_dev_io(sctx, sctx->stripes[0].dev,
1802			      btrfs_stripe_nr_to_offset(nr_stripes));
1803	blk_start_plug(&plug);
1804	for (int i = 0; i < nr_stripes; i++) {
1805		struct scrub_stripe *stripe = &sctx->stripes[first_slot + i];
1806
1807		/* Those stripes should be initialized. */
1808		ASSERT(test_bit(SCRUB_STRIPE_FLAG_INITIALIZED, &stripe->state));
1809		scrub_submit_initial_read(sctx, stripe);
1810	}
1811	blk_finish_plug(&plug);
1812}
1813
1814static int flush_scrub_stripes(struct scrub_ctx *sctx)
1815{
1816	struct btrfs_fs_info *fs_info = sctx->fs_info;
1817	struct scrub_stripe *stripe;
1818	const int nr_stripes = sctx->cur_stripe;
1819	int ret = 0;
1820
1821	if (!nr_stripes)
1822		return 0;
1823
1824	ASSERT(test_bit(SCRUB_STRIPE_FLAG_INITIALIZED, &sctx->stripes[0].state));
1825
1826	/* Submit the stripes which are populated but not submitted. */
1827	if (nr_stripes % SCRUB_STRIPES_PER_GROUP) {
1828		const int first_slot = round_down(nr_stripes, SCRUB_STRIPES_PER_GROUP);
1829
1830		submit_initial_group_read(sctx, first_slot, nr_stripes - first_slot);
1831	}
1832
1833	for (int i = 0; i < nr_stripes; i++) {
1834		stripe = &sctx->stripes[i];
1835
1836		wait_event(stripe->repair_wait,
1837			   test_bit(SCRUB_STRIPE_FLAG_REPAIR_DONE, &stripe->state));
1838	}
1839
1840	/* Submit for dev-replace. */
1841	if (sctx->is_dev_replace) {
1842		/*
1843		 * For dev-replace, if we know there is something wrong with
1844		 * metadata, we should immediately abort.
1845		 */
1846		for (int i = 0; i < nr_stripes; i++) {
1847			if (stripe_has_metadata_error(&sctx->stripes[i])) {
1848				ret = -EIO;
1849				goto out;
1850			}
1851		}
1852		for (int i = 0; i < nr_stripes; i++) {
1853			unsigned long good;
1854
1855			stripe = &sctx->stripes[i];
1856
1857			ASSERT(stripe->dev == fs_info->dev_replace.srcdev);
1858
1859			bitmap_andnot(&good, &stripe->extent_sector_bitmap,
1860				      &stripe->error_bitmap, stripe->nr_sectors);
1861			scrub_write_sectors(sctx, stripe, good, true);
1862		}
1863	}
1864
1865	/* Wait for the above writebacks to finish. */
1866	for (int i = 0; i < nr_stripes; i++) {
1867		stripe = &sctx->stripes[i];
1868
1869		wait_scrub_stripe_io(stripe);
1870		scrub_reset_stripe(stripe);
1871	}
1872out:
1873	sctx->cur_stripe = 0;
1874	return ret;
1875}
1876
1877static void raid56_scrub_wait_endio(struct bio *bio)
1878{
1879	complete(bio->bi_private);
1880}
1881
1882static int queue_scrub_stripe(struct scrub_ctx *sctx, struct btrfs_block_group *bg,
1883			      struct btrfs_device *dev, int mirror_num,
1884			      u64 logical, u32 length, u64 physical,
1885			      u64 *found_logical_ret)
1886{
1887	struct scrub_stripe *stripe;
1888	int ret;
1889
1890	/*
1891	 * There should always be one slot left, as caller filling the last
1892	 * slot should flush them all.
1893	 */
1894	ASSERT(sctx->cur_stripe < SCRUB_TOTAL_STRIPES);
1895
1896	/* @found_logical_ret must be specified. */
1897	ASSERT(found_logical_ret);
1898
1899	stripe = &sctx->stripes[sctx->cur_stripe];
1900	scrub_reset_stripe(stripe);
1901	ret = scrub_find_fill_first_stripe(bg, &sctx->extent_path,
1902					   &sctx->csum_path, dev, physical,
1903					   mirror_num, logical, length, stripe);
1904	/* Either >0 as no more extents or <0 for error. */
1905	if (ret)
1906		return ret;
1907	*found_logical_ret = stripe->logical;
1908	sctx->cur_stripe++;
1909
1910	/* We filled one group, submit it. */
1911	if (sctx->cur_stripe % SCRUB_STRIPES_PER_GROUP == 0) {
1912		const int first_slot = sctx->cur_stripe - SCRUB_STRIPES_PER_GROUP;
1913
1914		submit_initial_group_read(sctx, first_slot, SCRUB_STRIPES_PER_GROUP);
1915	}
1916
1917	/* Last slot used, flush them all. */
1918	if (sctx->cur_stripe == SCRUB_TOTAL_STRIPES)
1919		return flush_scrub_stripes(sctx);
1920	return 0;
1921}
1922
1923static int scrub_raid56_parity_stripe(struct scrub_ctx *sctx,
1924				      struct btrfs_device *scrub_dev,
1925				      struct btrfs_block_group *bg,
1926				      struct btrfs_chunk_map *map,
1927				      u64 full_stripe_start)
1928{
1929	DECLARE_COMPLETION_ONSTACK(io_done);
1930	struct btrfs_fs_info *fs_info = sctx->fs_info;
1931	struct btrfs_raid_bio *rbio;
1932	struct btrfs_io_context *bioc = NULL;
1933	struct btrfs_path extent_path = { 0 };
1934	struct btrfs_path csum_path = { 0 };
1935	struct bio *bio;
1936	struct scrub_stripe *stripe;
1937	bool all_empty = true;
1938	const int data_stripes = nr_data_stripes(map);
1939	unsigned long extent_bitmap = 0;
1940	u64 length = btrfs_stripe_nr_to_offset(data_stripes);
1941	int ret;
1942
1943	ASSERT(sctx->raid56_data_stripes);
1944
1945	/*
1946	 * For data stripe search, we cannot re-use the same extent/csum paths,
1947	 * as the data stripe bytenr may be smaller than previous extent.  Thus
1948	 * we have to use our own extent/csum paths.
1949	 */
1950	extent_path.search_commit_root = 1;
1951	extent_path.skip_locking = 1;
1952	csum_path.search_commit_root = 1;
1953	csum_path.skip_locking = 1;
1954
1955	for (int i = 0; i < data_stripes; i++) {
1956		int stripe_index;
1957		int rot;
1958		u64 physical;
1959
1960		stripe = &sctx->raid56_data_stripes[i];
1961		rot = div_u64(full_stripe_start - bg->start,
1962			      data_stripes) >> BTRFS_STRIPE_LEN_SHIFT;
1963		stripe_index = (i + rot) % map->num_stripes;
1964		physical = map->stripes[stripe_index].physical +
1965			   btrfs_stripe_nr_to_offset(rot);
1966
1967		scrub_reset_stripe(stripe);
1968		set_bit(SCRUB_STRIPE_FLAG_NO_REPORT, &stripe->state);
1969		ret = scrub_find_fill_first_stripe(bg, &extent_path, &csum_path,
1970				map->stripes[stripe_index].dev, physical, 1,
1971				full_stripe_start + btrfs_stripe_nr_to_offset(i),
1972				BTRFS_STRIPE_LEN, stripe);
1973		if (ret < 0)
1974			goto out;
1975		/*
1976		 * No extent in this data stripe, need to manually mark them
1977		 * initialized to make later read submission happy.
1978		 */
1979		if (ret > 0) {
1980			stripe->logical = full_stripe_start +
1981					  btrfs_stripe_nr_to_offset(i);
1982			stripe->dev = map->stripes[stripe_index].dev;
1983			stripe->mirror_num = 1;
1984			set_bit(SCRUB_STRIPE_FLAG_INITIALIZED, &stripe->state);
1985		}
1986	}
1987
1988	/* Check if all data stripes are empty. */
1989	for (int i = 0; i < data_stripes; i++) {
1990		stripe = &sctx->raid56_data_stripes[i];
1991		if (!bitmap_empty(&stripe->extent_sector_bitmap, stripe->nr_sectors)) {
1992			all_empty = false;
1993			break;
1994		}
1995	}
1996	if (all_empty) {
1997		ret = 0;
1998		goto out;
1999	}
2000
2001	for (int i = 0; i < data_stripes; i++) {
2002		stripe = &sctx->raid56_data_stripes[i];
2003		scrub_submit_initial_read(sctx, stripe);
2004	}
2005	for (int i = 0; i < data_stripes; i++) {
2006		stripe = &sctx->raid56_data_stripes[i];
2007
2008		wait_event(stripe->repair_wait,
2009			   test_bit(SCRUB_STRIPE_FLAG_REPAIR_DONE, &stripe->state));
2010	}
2011	/* For now, no zoned support for RAID56. */
2012	ASSERT(!btrfs_is_zoned(sctx->fs_info));
2013
2014	/*
2015	 * Now all data stripes are properly verified. Check if we have any
2016	 * unrepaired, if so abort immediately or we could further corrupt the
2017	 * P/Q stripes.
2018	 *
2019	 * During the loop, also populate extent_bitmap.
2020	 */
2021	for (int i = 0; i < data_stripes; i++) {
2022		unsigned long error;
2023
2024		stripe = &sctx->raid56_data_stripes[i];
2025
2026		/*
2027		 * We should only check the errors where there is an extent.
2028		 * As we may hit an empty data stripe while it's missing.
2029		 */
2030		bitmap_and(&error, &stripe->error_bitmap,
2031			   &stripe->extent_sector_bitmap, stripe->nr_sectors);
2032		if (!bitmap_empty(&error, stripe->nr_sectors)) {
2033			btrfs_err(fs_info,
2034"unrepaired sectors detected, full stripe %llu data stripe %u errors %*pbl",
2035				  full_stripe_start, i, stripe->nr_sectors,
2036				  &error);
2037			ret = -EIO;
2038			goto out;
2039		}
2040		bitmap_or(&extent_bitmap, &extent_bitmap,
2041			  &stripe->extent_sector_bitmap, stripe->nr_sectors);
2042	}
2043
2044	/* Now we can check and regenerate the P/Q stripe. */
2045	bio = bio_alloc(NULL, 1, REQ_OP_READ, GFP_NOFS);
2046	bio->bi_iter.bi_sector = full_stripe_start >> SECTOR_SHIFT;
2047	bio->bi_private = &io_done;
2048	bio->bi_end_io = raid56_scrub_wait_endio;
2049
2050	btrfs_bio_counter_inc_blocked(fs_info);
2051	ret = btrfs_map_block(fs_info, BTRFS_MAP_WRITE, full_stripe_start,
2052			      &length, &bioc, NULL, NULL);
2053	if (ret < 0) {
2054		btrfs_put_bioc(bioc);
2055		btrfs_bio_counter_dec(fs_info);
2056		goto out;
2057	}
2058	rbio = raid56_parity_alloc_scrub_rbio(bio, bioc, scrub_dev, &extent_bitmap,
2059				BTRFS_STRIPE_LEN >> fs_info->sectorsize_bits);
2060	btrfs_put_bioc(bioc);
2061	if (!rbio) {
2062		ret = -ENOMEM;
2063		btrfs_bio_counter_dec(fs_info);
2064		goto out;
2065	}
2066	/* Use the recovered stripes as cache to avoid read them from disk again. */
2067	for (int i = 0; i < data_stripes; i++) {
2068		stripe = &sctx->raid56_data_stripes[i];
2069
2070		raid56_parity_cache_data_pages(rbio, stripe->pages,
2071				full_stripe_start + (i << BTRFS_STRIPE_LEN_SHIFT));
2072	}
2073	raid56_parity_submit_scrub_rbio(rbio);
2074	wait_for_completion_io(&io_done);
2075	ret = blk_status_to_errno(bio->bi_status);
2076	bio_put(bio);
2077	btrfs_bio_counter_dec(fs_info);
2078
2079	btrfs_release_path(&extent_path);
2080	btrfs_release_path(&csum_path);
2081out:
2082	return ret;
2083}
2084
2085/*
2086 * Scrub one range which can only has simple mirror based profile.
2087 * (Including all range in SINGLE/DUP/RAID1/RAID1C*, and each stripe in
2088 *  RAID0/RAID10).
2089 *
2090 * Since we may need to handle a subset of block group, we need @logical_start
2091 * and @logical_length parameter.
2092 */
2093static int scrub_simple_mirror(struct scrub_ctx *sctx,
2094			       struct btrfs_block_group *bg,
2095			       struct btrfs_chunk_map *map,
2096			       u64 logical_start, u64 logical_length,
2097			       struct btrfs_device *device,
2098			       u64 physical, int mirror_num)
2099{
2100	struct btrfs_fs_info *fs_info = sctx->fs_info;
2101	const u64 logical_end = logical_start + logical_length;
2102	u64 cur_logical = logical_start;
2103	int ret;
2104
2105	/* The range must be inside the bg */
2106	ASSERT(logical_start >= bg->start && logical_end <= bg->start + bg->length);
2107
2108	/* Go through each extent items inside the logical range */
2109	while (cur_logical < logical_end) {
2110		u64 found_logical = U64_MAX;
2111		u64 cur_physical = physical + cur_logical - logical_start;
2112
2113		/* Canceled? */
2114		if (atomic_read(&fs_info->scrub_cancel_req) ||
2115		    atomic_read(&sctx->cancel_req)) {
2116			ret = -ECANCELED;
2117			break;
2118		}
2119		/* Paused? */
2120		if (atomic_read(&fs_info->scrub_pause_req)) {
2121			/* Push queued extents */
2122			scrub_blocked_if_needed(fs_info);
2123		}
2124		/* Block group removed? */
2125		spin_lock(&bg->lock);
2126		if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &bg->runtime_flags)) {
2127			spin_unlock(&bg->lock);
2128			ret = 0;
2129			break;
2130		}
2131		spin_unlock(&bg->lock);
2132
2133		ret = queue_scrub_stripe(sctx, bg, device, mirror_num,
2134					 cur_logical, logical_end - cur_logical,
2135					 cur_physical, &found_logical);
2136		if (ret > 0) {
2137			/* No more extent, just update the accounting */
2138			sctx->stat.last_physical = physical + logical_length;
2139			ret = 0;
2140			break;
2141		}
2142		if (ret < 0)
2143			break;
2144
2145		/* queue_scrub_stripe() returned 0, @found_logical must be updated. */
2146		ASSERT(found_logical != U64_MAX);
2147		cur_logical = found_logical + BTRFS_STRIPE_LEN;
2148
2149		/* Don't hold CPU for too long time */
2150		cond_resched();
2151	}
2152	return ret;
2153}
2154
2155/* Calculate the full stripe length for simple stripe based profiles */
2156static u64 simple_stripe_full_stripe_len(const struct btrfs_chunk_map *map)
2157{
2158	ASSERT(map->type & (BTRFS_BLOCK_GROUP_RAID0 |
2159			    BTRFS_BLOCK_GROUP_RAID10));
2160
2161	return btrfs_stripe_nr_to_offset(map->num_stripes / map->sub_stripes);
2162}
2163
2164/* Get the logical bytenr for the stripe */
2165static u64 simple_stripe_get_logical(struct btrfs_chunk_map *map,
2166				     struct btrfs_block_group *bg,
2167				     int stripe_index)
2168{
2169	ASSERT(map->type & (BTRFS_BLOCK_GROUP_RAID0 |
2170			    BTRFS_BLOCK_GROUP_RAID10));
2171	ASSERT(stripe_index < map->num_stripes);
2172
2173	/*
2174	 * (stripe_index / sub_stripes) gives how many data stripes we need to
2175	 * skip.
2176	 */
2177	return btrfs_stripe_nr_to_offset(stripe_index / map->sub_stripes) +
2178	       bg->start;
2179}
2180
2181/* Get the mirror number for the stripe */
2182static int simple_stripe_mirror_num(struct btrfs_chunk_map *map, int stripe_index)
2183{
2184	ASSERT(map->type & (BTRFS_BLOCK_GROUP_RAID0 |
2185			    BTRFS_BLOCK_GROUP_RAID10));
2186	ASSERT(stripe_index < map->num_stripes);
2187
2188	/* For RAID0, it's fixed to 1, for RAID10 it's 0,1,0,1... */
2189	return stripe_index % map->sub_stripes + 1;
2190}
2191
2192static int scrub_simple_stripe(struct scrub_ctx *sctx,
2193			       struct btrfs_block_group *bg,
2194			       struct btrfs_chunk_map *map,
2195			       struct btrfs_device *device,
2196			       int stripe_index)
2197{
2198	const u64 logical_increment = simple_stripe_full_stripe_len(map);
2199	const u64 orig_logical = simple_stripe_get_logical(map, bg, stripe_index);
2200	const u64 orig_physical = map->stripes[stripe_index].physical;
2201	const int mirror_num = simple_stripe_mirror_num(map, stripe_index);
2202	u64 cur_logical = orig_logical;
2203	u64 cur_physical = orig_physical;
2204	int ret = 0;
2205
2206	while (cur_logical < bg->start + bg->length) {
2207		/*
2208		 * Inside each stripe, RAID0 is just SINGLE, and RAID10 is
2209		 * just RAID1, so we can reuse scrub_simple_mirror() to scrub
2210		 * this stripe.
2211		 */
2212		ret = scrub_simple_mirror(sctx, bg, map, cur_logical,
2213					  BTRFS_STRIPE_LEN, device, cur_physical,
2214					  mirror_num);
2215		if (ret)
2216			return ret;
2217		/* Skip to next stripe which belongs to the target device */
2218		cur_logical += logical_increment;
2219		/* For physical offset, we just go to next stripe */
2220		cur_physical += BTRFS_STRIPE_LEN;
2221	}
2222	return ret;
2223}
2224
2225static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
2226					   struct btrfs_block_group *bg,
2227					   struct btrfs_chunk_map *map,
2228					   struct btrfs_device *scrub_dev,
2229					   int stripe_index)
2230{
2231	struct btrfs_fs_info *fs_info = sctx->fs_info;
2232	const u64 profile = map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK;
2233	const u64 chunk_logical = bg->start;
2234	int ret;
2235	int ret2;
2236	u64 physical = map->stripes[stripe_index].physical;
2237	const u64 dev_stripe_len = btrfs_calc_stripe_length(map);
2238	const u64 physical_end = physical + dev_stripe_len;
2239	u64 logical;
2240	u64 logic_end;
2241	/* The logical increment after finishing one stripe */
2242	u64 increment;
2243	/* Offset inside the chunk */
2244	u64 offset;
2245	u64 stripe_logical;
2246	int stop_loop = 0;
2247
2248	/* Extent_path should be released by now. */
2249	ASSERT(sctx->extent_path.nodes[0] == NULL);
2250
2251	scrub_blocked_if_needed(fs_info);
2252
2253	if (sctx->is_dev_replace &&
2254	    btrfs_dev_is_sequential(sctx->wr_tgtdev, physical)) {
2255		mutex_lock(&sctx->wr_lock);
2256		sctx->write_pointer = physical;
2257		mutex_unlock(&sctx->wr_lock);
2258	}
2259
2260	/* Prepare the extra data stripes used by RAID56. */
2261	if (profile & BTRFS_BLOCK_GROUP_RAID56_MASK) {
2262		ASSERT(sctx->raid56_data_stripes == NULL);
2263
2264		sctx->raid56_data_stripes = kcalloc(nr_data_stripes(map),
2265						    sizeof(struct scrub_stripe),
2266						    GFP_KERNEL);
2267		if (!sctx->raid56_data_stripes) {
2268			ret = -ENOMEM;
2269			goto out;
2270		}
2271		for (int i = 0; i < nr_data_stripes(map); i++) {
2272			ret = init_scrub_stripe(fs_info,
2273						&sctx->raid56_data_stripes[i]);
2274			if (ret < 0)
2275				goto out;
2276			sctx->raid56_data_stripes[i].bg = bg;
2277			sctx->raid56_data_stripes[i].sctx = sctx;
2278		}
2279	}
2280	/*
2281	 * There used to be a big double loop to handle all profiles using the
2282	 * same routine, which grows larger and more gross over time.
2283	 *
2284	 * So here we handle each profile differently, so simpler profiles
2285	 * have simpler scrubbing function.
2286	 */
2287	if (!(profile & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10 |
2288			 BTRFS_BLOCK_GROUP_RAID56_MASK))) {
2289		/*
2290		 * Above check rules out all complex profile, the remaining
2291		 * profiles are SINGLE|DUP|RAID1|RAID1C*, which is simple
2292		 * mirrored duplication without stripe.
2293		 *
2294		 * Only @physical and @mirror_num needs to calculated using
2295		 * @stripe_index.
2296		 */
2297		ret = scrub_simple_mirror(sctx, bg, map, bg->start, bg->length,
2298				scrub_dev, map->stripes[stripe_index].physical,
2299				stripe_index + 1);
2300		offset = 0;
2301		goto out;
2302	}
2303	if (profile & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID10)) {
2304		ret = scrub_simple_stripe(sctx, bg, map, scrub_dev, stripe_index);
2305		offset = btrfs_stripe_nr_to_offset(stripe_index / map->sub_stripes);
2306		goto out;
2307	}
2308
2309	/* Only RAID56 goes through the old code */
2310	ASSERT(map->type & BTRFS_BLOCK_GROUP_RAID56_MASK);
2311	ret = 0;
2312
2313	/* Calculate the logical end of the stripe */
2314	get_raid56_logic_offset(physical_end, stripe_index,
2315				map, &logic_end, NULL);
2316	logic_end += chunk_logical;
2317
2318	/* Initialize @offset in case we need to go to out: label */
2319	get_raid56_logic_offset(physical, stripe_index, map, &offset, NULL);
2320	increment = btrfs_stripe_nr_to_offset(nr_data_stripes(map));
2321
2322	/*
2323	 * Due to the rotation, for RAID56 it's better to iterate each stripe
2324	 * using their physical offset.
2325	 */
2326	while (physical < physical_end) {
2327		ret = get_raid56_logic_offset(physical, stripe_index, map,
2328					      &logical, &stripe_logical);
2329		logical += chunk_logical;
2330		if (ret) {
2331			/* it is parity strip */
2332			stripe_logical += chunk_logical;
2333			ret = scrub_raid56_parity_stripe(sctx, scrub_dev, bg,
2334							 map, stripe_logical);
2335			if (ret)
2336				goto out;
2337			goto next;
2338		}
2339
2340		/*
2341		 * Now we're at a data stripe, scrub each extents in the range.
2342		 *
2343		 * At this stage, if we ignore the repair part, inside each data
2344		 * stripe it is no different than SINGLE profile.
2345		 * We can reuse scrub_simple_mirror() here, as the repair part
2346		 * is still based on @mirror_num.
2347		 */
2348		ret = scrub_simple_mirror(sctx, bg, map, logical, BTRFS_STRIPE_LEN,
2349					  scrub_dev, physical, 1);
2350		if (ret < 0)
2351			goto out;
2352next:
2353		logical += increment;
2354		physical += BTRFS_STRIPE_LEN;
2355		spin_lock(&sctx->stat_lock);
2356		if (stop_loop)
2357			sctx->stat.last_physical =
2358				map->stripes[stripe_index].physical + dev_stripe_len;
2359		else
2360			sctx->stat.last_physical = physical;
2361		spin_unlock(&sctx->stat_lock);
2362		if (stop_loop)
2363			break;
2364	}
2365out:
2366	ret2 = flush_scrub_stripes(sctx);
2367	if (!ret)
2368		ret = ret2;
2369	btrfs_release_path(&sctx->extent_path);
2370	btrfs_release_path(&sctx->csum_path);
2371
2372	if (sctx->raid56_data_stripes) {
2373		for (int i = 0; i < nr_data_stripes(map); i++)
2374			release_scrub_stripe(&sctx->raid56_data_stripes[i]);
2375		kfree(sctx->raid56_data_stripes);
2376		sctx->raid56_data_stripes = NULL;
2377	}
2378
2379	if (sctx->is_dev_replace && ret >= 0) {
2380		int ret2;
2381
2382		ret2 = sync_write_pointer_for_zoned(sctx,
2383				chunk_logical + offset,
2384				map->stripes[stripe_index].physical,
2385				physical_end);
2386		if (ret2)
2387			ret = ret2;
2388	}
2389
2390	return ret < 0 ? ret : 0;
2391}
2392
2393static noinline_for_stack int scrub_chunk(struct scrub_ctx *sctx,
2394					  struct btrfs_block_group *bg,
2395					  struct btrfs_device *scrub_dev,
2396					  u64 dev_offset,
2397					  u64 dev_extent_len)
2398{
2399	struct btrfs_fs_info *fs_info = sctx->fs_info;
2400	struct btrfs_chunk_map *map;
2401	int i;
2402	int ret = 0;
2403
2404	map = btrfs_find_chunk_map(fs_info, bg->start, bg->length);
2405	if (!map) {
2406		/*
2407		 * Might have been an unused block group deleted by the cleaner
2408		 * kthread or relocation.
2409		 */
2410		spin_lock(&bg->lock);
2411		if (!test_bit(BLOCK_GROUP_FLAG_REMOVED, &bg->runtime_flags))
2412			ret = -EINVAL;
2413		spin_unlock(&bg->lock);
2414
2415		return ret;
2416	}
2417	if (map->start != bg->start)
2418		goto out;
2419	if (map->chunk_len < dev_extent_len)
2420		goto out;
2421
2422	for (i = 0; i < map->num_stripes; ++i) {
2423		if (map->stripes[i].dev->bdev == scrub_dev->bdev &&
2424		    map->stripes[i].physical == dev_offset) {
2425			ret = scrub_stripe(sctx, bg, map, scrub_dev, i);
2426			if (ret)
2427				goto out;
2428		}
2429	}
2430out:
2431	btrfs_free_chunk_map(map);
2432
2433	return ret;
2434}
2435
2436static int finish_extent_writes_for_zoned(struct btrfs_root *root,
2437					  struct btrfs_block_group *cache)
2438{
2439	struct btrfs_fs_info *fs_info = cache->fs_info;
2440	struct btrfs_trans_handle *trans;
2441
2442	if (!btrfs_is_zoned(fs_info))
2443		return 0;
2444
2445	btrfs_wait_block_group_reservations(cache);
2446	btrfs_wait_nocow_writers(cache);
2447	btrfs_wait_ordered_roots(fs_info, U64_MAX, cache->start, cache->length);
2448
2449	trans = btrfs_join_transaction(root);
2450	if (IS_ERR(trans))
2451		return PTR_ERR(trans);
2452	return btrfs_commit_transaction(trans);
2453}
2454
2455static noinline_for_stack
2456int scrub_enumerate_chunks(struct scrub_ctx *sctx,
2457			   struct btrfs_device *scrub_dev, u64 start, u64 end)
2458{
2459	struct btrfs_dev_extent *dev_extent = NULL;
2460	struct btrfs_path *path;
2461	struct btrfs_fs_info *fs_info = sctx->fs_info;
2462	struct btrfs_root *root = fs_info->dev_root;
2463	u64 chunk_offset;
2464	int ret = 0;
2465	int ro_set;
2466	int slot;
2467	struct extent_buffer *l;
2468	struct btrfs_key key;
2469	struct btrfs_key found_key;
2470	struct btrfs_block_group *cache;
2471	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
2472
2473	path = btrfs_alloc_path();
2474	if (!path)
2475		return -ENOMEM;
2476
2477	path->reada = READA_FORWARD;
2478	path->search_commit_root = 1;
2479	path->skip_locking = 1;
2480
2481	key.objectid = scrub_dev->devid;
2482	key.offset = 0ull;
2483	key.type = BTRFS_DEV_EXTENT_KEY;
2484
2485	while (1) {
2486		u64 dev_extent_len;
2487
2488		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2489		if (ret < 0)
2490			break;
2491		if (ret > 0) {
2492			if (path->slots[0] >=
2493			    btrfs_header_nritems(path->nodes[0])) {
2494				ret = btrfs_next_leaf(root, path);
2495				if (ret < 0)
2496					break;
2497				if (ret > 0) {
2498					ret = 0;
2499					break;
2500				}
2501			} else {
2502				ret = 0;
2503			}
2504		}
2505
2506		l = path->nodes[0];
2507		slot = path->slots[0];
2508
2509		btrfs_item_key_to_cpu(l, &found_key, slot);
2510
2511		if (found_key.objectid != scrub_dev->devid)
2512			break;
2513
2514		if (found_key.type != BTRFS_DEV_EXTENT_KEY)
2515			break;
2516
2517		if (found_key.offset >= end)
2518			break;
2519
2520		if (found_key.offset < key.offset)
2521			break;
2522
2523		dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
2524		dev_extent_len = btrfs_dev_extent_length(l, dev_extent);
2525
2526		if (found_key.offset + dev_extent_len <= start)
2527			goto skip;
2528
2529		chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
2530
2531		/*
2532		 * get a reference on the corresponding block group to prevent
2533		 * the chunk from going away while we scrub it
2534		 */
2535		cache = btrfs_lookup_block_group(fs_info, chunk_offset);
2536
2537		/* some chunks are removed but not committed to disk yet,
2538		 * continue scrubbing */
2539		if (!cache)
2540			goto skip;
2541
2542		ASSERT(cache->start <= chunk_offset);
2543		/*
2544		 * We are using the commit root to search for device extents, so
2545		 * that means we could have found a device extent item from a
2546		 * block group that was deleted in the current transaction. The
2547		 * logical start offset of the deleted block group, stored at
2548		 * @chunk_offset, might be part of the logical address range of
2549		 * a new block group (which uses different physical extents).
2550		 * In this case btrfs_lookup_block_group() has returned the new
2551		 * block group, and its start address is less than @chunk_offset.
2552		 *
2553		 * We skip such new block groups, because it's pointless to
2554		 * process them, as we won't find their extents because we search
2555		 * for them using the commit root of the extent tree. For a device
2556		 * replace it's also fine to skip it, we won't miss copying them
2557		 * to the target device because we have the write duplication
2558		 * setup through the regular write path (by btrfs_map_block()),
2559		 * and we have committed a transaction when we started the device
2560		 * replace, right after setting up the device replace state.
2561		 */
2562		if (cache->start < chunk_offset) {
2563			btrfs_put_block_group(cache);
2564			goto skip;
2565		}
2566
2567		if (sctx->is_dev_replace && btrfs_is_zoned(fs_info)) {
2568			if (!test_bit(BLOCK_GROUP_FLAG_TO_COPY, &cache->runtime_flags)) {
2569				btrfs_put_block_group(cache);
2570				goto skip;
2571			}
2572		}
2573
2574		/*
2575		 * Make sure that while we are scrubbing the corresponding block
2576		 * group doesn't get its logical address and its device extents
2577		 * reused for another block group, which can possibly be of a
2578		 * different type and different profile. We do this to prevent
2579		 * false error detections and crashes due to bogus attempts to
2580		 * repair extents.
2581		 */
2582		spin_lock(&cache->lock);
2583		if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &cache->runtime_flags)) {
2584			spin_unlock(&cache->lock);
2585			btrfs_put_block_group(cache);
2586			goto skip;
2587		}
2588		btrfs_freeze_block_group(cache);
2589		spin_unlock(&cache->lock);
2590
2591		/*
2592		 * we need call btrfs_inc_block_group_ro() with scrubs_paused,
2593		 * to avoid deadlock caused by:
2594		 * btrfs_inc_block_group_ro()
2595		 * -> btrfs_wait_for_commit()
2596		 * -> btrfs_commit_transaction()
2597		 * -> btrfs_scrub_pause()
2598		 */
2599		scrub_pause_on(fs_info);
2600
2601		/*
2602		 * Don't do chunk preallocation for scrub.
2603		 *
2604		 * This is especially important for SYSTEM bgs, or we can hit
2605		 * -EFBIG from btrfs_finish_chunk_alloc() like:
2606		 * 1. The only SYSTEM bg is marked RO.
2607		 *    Since SYSTEM bg is small, that's pretty common.
2608		 * 2. New SYSTEM bg will be allocated
2609		 *    Due to regular version will allocate new chunk.
2610		 * 3. New SYSTEM bg is empty and will get cleaned up
2611		 *    Before cleanup really happens, it's marked RO again.
2612		 * 4. Empty SYSTEM bg get scrubbed
2613		 *    We go back to 2.
2614		 *
2615		 * This can easily boost the amount of SYSTEM chunks if cleaner
2616		 * thread can't be triggered fast enough, and use up all space
2617		 * of btrfs_super_block::sys_chunk_array
2618		 *
2619		 * While for dev replace, we need to try our best to mark block
2620		 * group RO, to prevent race between:
2621		 * - Write duplication
2622		 *   Contains latest data
2623		 * - Scrub copy
2624		 *   Contains data from commit tree
2625		 *
2626		 * If target block group is not marked RO, nocow writes can
2627		 * be overwritten by scrub copy, causing data corruption.
2628		 * So for dev-replace, it's not allowed to continue if a block
2629		 * group is not RO.
2630		 */
2631		ret = btrfs_inc_block_group_ro(cache, sctx->is_dev_replace);
2632		if (!ret && sctx->is_dev_replace) {
2633			ret = finish_extent_writes_for_zoned(root, cache);
2634			if (ret) {
2635				btrfs_dec_block_group_ro(cache);
2636				scrub_pause_off(fs_info);
2637				btrfs_put_block_group(cache);
2638				break;
2639			}
2640		}
2641
2642		if (ret == 0) {
2643			ro_set = 1;
2644		} else if (ret == -ENOSPC && !sctx->is_dev_replace &&
2645			   !(cache->flags & BTRFS_BLOCK_GROUP_RAID56_MASK)) {
2646			/*
2647			 * btrfs_inc_block_group_ro return -ENOSPC when it
2648			 * failed in creating new chunk for metadata.
2649			 * It is not a problem for scrub, because
2650			 * metadata are always cowed, and our scrub paused
2651			 * commit_transactions.
2652			 *
2653			 * For RAID56 chunks, we have to mark them read-only
2654			 * for scrub, as later we would use our own cache
2655			 * out of RAID56 realm.
2656			 * Thus we want the RAID56 bg to be marked RO to
2657			 * prevent RMW from screwing up out cache.
2658			 */
2659			ro_set = 0;
2660		} else if (ret == -ETXTBSY) {
2661			btrfs_warn(fs_info,
2662		   "skipping scrub of block group %llu due to active swapfile",
2663				   cache->start);
2664			scrub_pause_off(fs_info);
2665			ret = 0;
2666			goto skip_unfreeze;
2667		} else {
2668			btrfs_warn(fs_info,
2669				   "failed setting block group ro: %d", ret);
2670			btrfs_unfreeze_block_group(cache);
2671			btrfs_put_block_group(cache);
2672			scrub_pause_off(fs_info);
2673			break;
2674		}
2675
2676		/*
2677		 * Now the target block is marked RO, wait for nocow writes to
2678		 * finish before dev-replace.
2679		 * COW is fine, as COW never overwrites extents in commit tree.
2680		 */
2681		if (sctx->is_dev_replace) {
2682			btrfs_wait_nocow_writers(cache);
2683			btrfs_wait_ordered_roots(fs_info, U64_MAX, cache->start,
2684					cache->length);
2685		}
2686
2687		scrub_pause_off(fs_info);
2688		down_write(&dev_replace->rwsem);
2689		dev_replace->cursor_right = found_key.offset + dev_extent_len;
2690		dev_replace->cursor_left = found_key.offset;
2691		dev_replace->item_needs_writeback = 1;
2692		up_write(&dev_replace->rwsem);
2693
2694		ret = scrub_chunk(sctx, cache, scrub_dev, found_key.offset,
2695				  dev_extent_len);
2696		if (sctx->is_dev_replace &&
2697		    !btrfs_finish_block_group_to_copy(dev_replace->srcdev,
2698						      cache, found_key.offset))
2699			ro_set = 0;
2700
2701		down_write(&dev_replace->rwsem);
2702		dev_replace->cursor_left = dev_replace->cursor_right;
2703		dev_replace->item_needs_writeback = 1;
2704		up_write(&dev_replace->rwsem);
2705
2706		if (ro_set)
2707			btrfs_dec_block_group_ro(cache);
2708
2709		/*
2710		 * We might have prevented the cleaner kthread from deleting
2711		 * this block group if it was already unused because we raced
2712		 * and set it to RO mode first. So add it back to the unused
2713		 * list, otherwise it might not ever be deleted unless a manual
2714		 * balance is triggered or it becomes used and unused again.
2715		 */
2716		spin_lock(&cache->lock);
2717		if (!test_bit(BLOCK_GROUP_FLAG_REMOVED, &cache->runtime_flags) &&
2718		    !cache->ro && cache->reserved == 0 && cache->used == 0) {
2719			spin_unlock(&cache->lock);
2720			if (btrfs_test_opt(fs_info, DISCARD_ASYNC))
2721				btrfs_discard_queue_work(&fs_info->discard_ctl,
2722							 cache);
2723			else
2724				btrfs_mark_bg_unused(cache);
2725		} else {
2726			spin_unlock(&cache->lock);
2727		}
2728skip_unfreeze:
2729		btrfs_unfreeze_block_group(cache);
2730		btrfs_put_block_group(cache);
2731		if (ret)
2732			break;
2733		if (sctx->is_dev_replace &&
2734		    atomic64_read(&dev_replace->num_write_errors) > 0) {
2735			ret = -EIO;
2736			break;
2737		}
2738		if (sctx->stat.malloc_errors > 0) {
2739			ret = -ENOMEM;
2740			break;
2741		}
2742skip:
2743		key.offset = found_key.offset + dev_extent_len;
2744		btrfs_release_path(path);
2745	}
2746
2747	btrfs_free_path(path);
2748
2749	return ret;
2750}
2751
2752static int scrub_one_super(struct scrub_ctx *sctx, struct btrfs_device *dev,
2753			   struct page *page, u64 physical, u64 generation)
2754{
2755	struct btrfs_fs_info *fs_info = sctx->fs_info;
2756	struct bio_vec bvec;
2757	struct bio bio;
2758	struct btrfs_super_block *sb = page_address(page);
2759	int ret;
2760
2761	bio_init(&bio, dev->bdev, &bvec, 1, REQ_OP_READ);
2762	bio.bi_iter.bi_sector = physical >> SECTOR_SHIFT;
2763	__bio_add_page(&bio, page, BTRFS_SUPER_INFO_SIZE, 0);
2764	ret = submit_bio_wait(&bio);
2765	bio_uninit(&bio);
2766
2767	if (ret < 0)
2768		return ret;
2769	ret = btrfs_check_super_csum(fs_info, sb);
2770	if (ret != 0) {
2771		btrfs_err_rl(fs_info,
2772			"super block at physical %llu devid %llu has bad csum",
2773			physical, dev->devid);
2774		return -EIO;
2775	}
2776	if (btrfs_super_generation(sb) != generation) {
2777		btrfs_err_rl(fs_info,
2778"super block at physical %llu devid %llu has bad generation %llu expect %llu",
2779			     physical, dev->devid,
2780			     btrfs_super_generation(sb), generation);
2781		return -EUCLEAN;
2782	}
2783
2784	return btrfs_validate_super(fs_info, sb, -1);
2785}
2786
2787static noinline_for_stack int scrub_supers(struct scrub_ctx *sctx,
2788					   struct btrfs_device *scrub_dev)
2789{
2790	int	i;
2791	u64	bytenr;
2792	u64	gen;
2793	int ret = 0;
2794	struct page *page;
2795	struct btrfs_fs_info *fs_info = sctx->fs_info;
2796
2797	if (BTRFS_FS_ERROR(fs_info))
2798		return -EROFS;
2799
2800	page = alloc_page(GFP_KERNEL);
2801	if (!page) {
2802		spin_lock(&sctx->stat_lock);
2803		sctx->stat.malloc_errors++;
2804		spin_unlock(&sctx->stat_lock);
2805		return -ENOMEM;
2806	}
2807
2808	/* Seed devices of a new filesystem has their own generation. */
2809	if (scrub_dev->fs_devices != fs_info->fs_devices)
2810		gen = scrub_dev->generation;
2811	else
2812		gen = btrfs_get_last_trans_committed(fs_info);
2813
2814	for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
2815		ret = btrfs_sb_log_location(scrub_dev, i, 0, &bytenr);
2816		if (ret == -ENOENT)
2817			break;
2818
2819		if (ret) {
2820			spin_lock(&sctx->stat_lock);
2821			sctx->stat.super_errors++;
2822			spin_unlock(&sctx->stat_lock);
2823			continue;
2824		}
2825
2826		if (bytenr + BTRFS_SUPER_INFO_SIZE >
2827		    scrub_dev->commit_total_bytes)
2828			break;
2829		if (!btrfs_check_super_location(scrub_dev, bytenr))
2830			continue;
2831
2832		ret = scrub_one_super(sctx, scrub_dev, page, bytenr, gen);
2833		if (ret) {
2834			spin_lock(&sctx->stat_lock);
2835			sctx->stat.super_errors++;
2836			spin_unlock(&sctx->stat_lock);
2837		}
2838	}
2839	__free_page(page);
2840	return 0;
2841}
2842
2843static void scrub_workers_put(struct btrfs_fs_info *fs_info)
2844{
2845	if (refcount_dec_and_mutex_lock(&fs_info->scrub_workers_refcnt,
2846					&fs_info->scrub_lock)) {
2847		struct workqueue_struct *scrub_workers = fs_info->scrub_workers;
2848
2849		fs_info->scrub_workers = NULL;
2850		mutex_unlock(&fs_info->scrub_lock);
2851
2852		if (scrub_workers)
2853			destroy_workqueue(scrub_workers);
2854	}
2855}
2856
2857/*
2858 * get a reference count on fs_info->scrub_workers. start worker if necessary
2859 */
2860static noinline_for_stack int scrub_workers_get(struct btrfs_fs_info *fs_info)
2861{
2862	struct workqueue_struct *scrub_workers = NULL;
2863	unsigned int flags = WQ_FREEZABLE | WQ_UNBOUND;
2864	int max_active = fs_info->thread_pool_size;
2865	int ret = -ENOMEM;
2866
2867	if (refcount_inc_not_zero(&fs_info->scrub_workers_refcnt))
2868		return 0;
2869
2870	scrub_workers = alloc_workqueue("btrfs-scrub", flags, max_active);
2871	if (!scrub_workers)
2872		return -ENOMEM;
2873
2874	mutex_lock(&fs_info->scrub_lock);
2875	if (refcount_read(&fs_info->scrub_workers_refcnt) == 0) {
2876		ASSERT(fs_info->scrub_workers == NULL);
2877		fs_info->scrub_workers = scrub_workers;
2878		refcount_set(&fs_info->scrub_workers_refcnt, 1);
2879		mutex_unlock(&fs_info->scrub_lock);
2880		return 0;
2881	}
2882	/* Other thread raced in and created the workers for us */
2883	refcount_inc(&fs_info->scrub_workers_refcnt);
2884	mutex_unlock(&fs_info->scrub_lock);
2885
2886	ret = 0;
2887
2888	destroy_workqueue(scrub_workers);
2889	return ret;
2890}
2891
2892int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
2893		    u64 end, struct btrfs_scrub_progress *progress,
2894		    int readonly, int is_dev_replace)
2895{
2896	struct btrfs_dev_lookup_args args = { .devid = devid };
2897	struct scrub_ctx *sctx;
2898	int ret;
2899	struct btrfs_device *dev;
2900	unsigned int nofs_flag;
2901	bool need_commit = false;
2902
2903	if (btrfs_fs_closing(fs_info))
2904		return -EAGAIN;
2905
2906	/* At mount time we have ensured nodesize is in the range of [4K, 64K]. */
2907	ASSERT(fs_info->nodesize <= BTRFS_STRIPE_LEN);
2908
2909	/*
2910	 * SCRUB_MAX_SECTORS_PER_BLOCK is calculated using the largest possible
2911	 * value (max nodesize / min sectorsize), thus nodesize should always
2912	 * be fine.
2913	 */
2914	ASSERT(fs_info->nodesize <=
2915	       SCRUB_MAX_SECTORS_PER_BLOCK << fs_info->sectorsize_bits);
2916
2917	/* Allocate outside of device_list_mutex */
2918	sctx = scrub_setup_ctx(fs_info, is_dev_replace);
2919	if (IS_ERR(sctx))
2920		return PTR_ERR(sctx);
2921
2922	ret = scrub_workers_get(fs_info);
2923	if (ret)
2924		goto out_free_ctx;
2925
2926	mutex_lock(&fs_info->fs_devices->device_list_mutex);
2927	dev = btrfs_find_device(fs_info->fs_devices, &args);
2928	if (!dev || (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state) &&
2929		     !is_dev_replace)) {
2930		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2931		ret = -ENODEV;
2932		goto out;
2933	}
2934
2935	if (!is_dev_replace && !readonly &&
2936	    !test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state)) {
2937		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2938		btrfs_err_in_rcu(fs_info,
2939			"scrub on devid %llu: filesystem on %s is not writable",
2940				 devid, btrfs_dev_name(dev));
2941		ret = -EROFS;
2942		goto out;
2943	}
2944
2945	mutex_lock(&fs_info->scrub_lock);
2946	if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &dev->dev_state) ||
2947	    test_bit(BTRFS_DEV_STATE_REPLACE_TGT, &dev->dev_state)) {
2948		mutex_unlock(&fs_info->scrub_lock);
2949		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2950		ret = -EIO;
2951		goto out;
2952	}
2953
2954	down_read(&fs_info->dev_replace.rwsem);
2955	if (dev->scrub_ctx ||
2956	    (!is_dev_replace &&
2957	     btrfs_dev_replace_is_ongoing(&fs_info->dev_replace))) {
2958		up_read(&fs_info->dev_replace.rwsem);
2959		mutex_unlock(&fs_info->scrub_lock);
2960		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2961		ret = -EINPROGRESS;
2962		goto out;
2963	}
2964	up_read(&fs_info->dev_replace.rwsem);
2965
2966	sctx->readonly = readonly;
2967	dev->scrub_ctx = sctx;
2968	mutex_unlock(&fs_info->fs_devices->device_list_mutex);
2969
2970	/*
2971	 * checking @scrub_pause_req here, we can avoid
2972	 * race between committing transaction and scrubbing.
2973	 */
2974	__scrub_blocked_if_needed(fs_info);
2975	atomic_inc(&fs_info->scrubs_running);
2976	mutex_unlock(&fs_info->scrub_lock);
2977
2978	/*
2979	 * In order to avoid deadlock with reclaim when there is a transaction
2980	 * trying to pause scrub, make sure we use GFP_NOFS for all the
2981	 * allocations done at btrfs_scrub_sectors() and scrub_sectors_for_parity()
2982	 * invoked by our callees. The pausing request is done when the
2983	 * transaction commit starts, and it blocks the transaction until scrub
2984	 * is paused (done at specific points at scrub_stripe() or right above
2985	 * before incrementing fs_info->scrubs_running).
2986	 */
2987	nofs_flag = memalloc_nofs_save();
2988	if (!is_dev_replace) {
2989		u64 old_super_errors;
2990
2991		spin_lock(&sctx->stat_lock);
2992		old_super_errors = sctx->stat.super_errors;
2993		spin_unlock(&sctx->stat_lock);
2994
2995		btrfs_info(fs_info, "scrub: started on devid %llu", devid);
2996		/*
2997		 * by holding device list mutex, we can
2998		 * kick off writing super in log tree sync.
2999		 */
3000		mutex_lock(&fs_info->fs_devices->device_list_mutex);
3001		ret = scrub_supers(sctx, dev);
3002		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3003
3004		spin_lock(&sctx->stat_lock);
3005		/*
3006		 * Super block errors found, but we can not commit transaction
3007		 * at current context, since btrfs_commit_transaction() needs
3008		 * to pause the current running scrub (hold by ourselves).
3009		 */
3010		if (sctx->stat.super_errors > old_super_errors && !sctx->readonly)
3011			need_commit = true;
3012		spin_unlock(&sctx->stat_lock);
3013	}
3014
3015	if (!ret)
3016		ret = scrub_enumerate_chunks(sctx, dev, start, end);
3017	memalloc_nofs_restore(nofs_flag);
3018
3019	atomic_dec(&fs_info->scrubs_running);
3020	wake_up(&fs_info->scrub_pause_wait);
3021
3022	if (progress)
3023		memcpy(progress, &sctx->stat, sizeof(*progress));
3024
3025	if (!is_dev_replace)
3026		btrfs_info(fs_info, "scrub: %s on devid %llu with status: %d",
3027			ret ? "not finished" : "finished", devid, ret);
3028
3029	mutex_lock(&fs_info->scrub_lock);
3030	dev->scrub_ctx = NULL;
3031	mutex_unlock(&fs_info->scrub_lock);
3032
3033	scrub_workers_put(fs_info);
3034	scrub_put_ctx(sctx);
3035
3036	/*
3037	 * We found some super block errors before, now try to force a
3038	 * transaction commit, as scrub has finished.
3039	 */
3040	if (need_commit) {
3041		struct btrfs_trans_handle *trans;
3042
3043		trans = btrfs_start_transaction(fs_info->tree_root, 0);
3044		if (IS_ERR(trans)) {
3045			ret = PTR_ERR(trans);
3046			btrfs_err(fs_info,
3047	"scrub: failed to start transaction to fix super block errors: %d", ret);
3048			return ret;
3049		}
3050		ret = btrfs_commit_transaction(trans);
3051		if (ret < 0)
3052			btrfs_err(fs_info,
3053	"scrub: failed to commit transaction to fix super block errors: %d", ret);
3054	}
3055	return ret;
3056out:
3057	scrub_workers_put(fs_info);
3058out_free_ctx:
3059	scrub_free_ctx(sctx);
3060
3061	return ret;
3062}
3063
3064void btrfs_scrub_pause(struct btrfs_fs_info *fs_info)
3065{
3066	mutex_lock(&fs_info->scrub_lock);
3067	atomic_inc(&fs_info->scrub_pause_req);
3068	while (atomic_read(&fs_info->scrubs_paused) !=
3069	       atomic_read(&fs_info->scrubs_running)) {
3070		mutex_unlock(&fs_info->scrub_lock);
3071		wait_event(fs_info->scrub_pause_wait,
3072			   atomic_read(&fs_info->scrubs_paused) ==
3073			   atomic_read(&fs_info->scrubs_running));
3074		mutex_lock(&fs_info->scrub_lock);
3075	}
3076	mutex_unlock(&fs_info->scrub_lock);
3077}
3078
3079void btrfs_scrub_continue(struct btrfs_fs_info *fs_info)
3080{
3081	atomic_dec(&fs_info->scrub_pause_req);
3082	wake_up(&fs_info->scrub_pause_wait);
3083}
3084
3085int btrfs_scrub_cancel(struct btrfs_fs_info *fs_info)
3086{
3087	mutex_lock(&fs_info->scrub_lock);
3088	if (!atomic_read(&fs_info->scrubs_running)) {
3089		mutex_unlock(&fs_info->scrub_lock);
3090		return -ENOTCONN;
3091	}
3092
3093	atomic_inc(&fs_info->scrub_cancel_req);
3094	while (atomic_read(&fs_info->scrubs_running)) {
3095		mutex_unlock(&fs_info->scrub_lock);
3096		wait_event(fs_info->scrub_pause_wait,
3097			   atomic_read(&fs_info->scrubs_running) == 0);
3098		mutex_lock(&fs_info->scrub_lock);
3099	}
3100	atomic_dec(&fs_info->scrub_cancel_req);
3101	mutex_unlock(&fs_info->scrub_lock);
3102
3103	return 0;
3104}
3105
3106int btrfs_scrub_cancel_dev(struct btrfs_device *dev)
3107{
3108	struct btrfs_fs_info *fs_info = dev->fs_info;
3109	struct scrub_ctx *sctx;
3110
3111	mutex_lock(&fs_info->scrub_lock);
3112	sctx = dev->scrub_ctx;
3113	if (!sctx) {
3114		mutex_unlock(&fs_info->scrub_lock);
3115		return -ENOTCONN;
3116	}
3117	atomic_inc(&sctx->cancel_req);
3118	while (dev->scrub_ctx) {
3119		mutex_unlock(&fs_info->scrub_lock);
3120		wait_event(fs_info->scrub_pause_wait,
3121			   dev->scrub_ctx == NULL);
3122		mutex_lock(&fs_info->scrub_lock);
3123	}
3124	mutex_unlock(&fs_info->scrub_lock);
3125
3126	return 0;
3127}
3128
3129int btrfs_scrub_progress(struct btrfs_fs_info *fs_info, u64 devid,
3130			 struct btrfs_scrub_progress *progress)
3131{
3132	struct btrfs_dev_lookup_args args = { .devid = devid };
3133	struct btrfs_device *dev;
3134	struct scrub_ctx *sctx = NULL;
3135
3136	mutex_lock(&fs_info->fs_devices->device_list_mutex);
3137	dev = btrfs_find_device(fs_info->fs_devices, &args);
3138	if (dev)
3139		sctx = dev->scrub_ctx;
3140	if (sctx)
3141		memcpy(progress, &sctx->stat, sizeof(*progress));
3142	mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3143
3144	return dev ? (sctx ? 0 : -ENOTCONN) : -ENODEV;
3145}