1/*
   2 * Copyright (C) 2011, 2012 STRATO.  All rights reserved.
   3 *
   4 * This program is free software; you can redistribute it and/or
   5 * modify it under the terms of the GNU General Public
   6 * License v2 as published by the Free Software Foundation.
   7 *
   8 * This program is distributed in the hope that it will be useful,
   9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11 * General Public License for more details.
  12 *
  13 * You should have received a copy of the GNU General Public
  14 * License along with this program; if not, write to the
  15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16 * Boston, MA 021110-1307, USA.
  17 */
  18
  19#include <linux/blkdev.h>
  20#include <linux/ratelimit.h>
  21#include "ctree.h"
  22#include "volumes.h"
  23#include "disk-io.h"
  24#include "ordered-data.h"
  25#include "transaction.h"
  26#include "backref.h"
  27#include "extent_io.h"
  28#include "dev-replace.h"
  29#include "check-integrity.h"
  30#include "rcu-string.h"
  31#include "raid56.h"
  32
  33/*
  34 * This is only the first step towards a full-features scrub. It reads all
  35 * extent and super block and verifies the checksums. In case a bad checksum
  36 * is found or the extent cannot be read, good data will be written back if
  37 * any can be found.
  38 *
  39 * Future enhancements:
  40 *  - In case an unrepairable extent is encountered, track which files are
  41 *    affected and report them
  42 *  - track and record media errors, throw out bad devices
  43 *  - add a mode to also read unallocated space
  44 */
  45
  46struct scrub_block;
  47struct scrub_ctx;
  48
  49/*
  50 * the following three values only influence the performance.
  51 * The last one configures the number of parallel and outstanding I/O
  52 * operations. The first two values configure an upper limit for the number
  53 * of (dynamically allocated) pages that are added to a bio.
  54 */
  55#define SCRUB_PAGES_PER_RD_BIO	32	/* 128k per bio */
  56#define SCRUB_PAGES_PER_WR_BIO	32	/* 128k per bio */
  57#define SCRUB_BIOS_PER_SCTX	64	/* 8MB per device in flight */
  58
  59/*
  60 * the following value times PAGE_SIZE needs to be large enough to match the
  61 * largest node/leaf/sector size that shall be supported.
  62 * Values larger than BTRFS_STRIPE_LEN are not supported.
  63 */
  64#define SCRUB_MAX_PAGES_PER_BLOCK	16	/* 64k per node/leaf/sector */
  65
  66struct scrub_recover {
  67	atomic_t		refs;
  68	struct btrfs_bio	*bbio;
  69	u64			map_length;
  70};
  71
  72struct scrub_page {
  73	struct scrub_block	*sblock;
  74	struct page		*page;
  75	struct btrfs_device	*dev;
  76	struct list_head	list;
  77	u64			flags;  /* extent flags */
  78	u64			generation;
  79	u64			logical;
  80	u64			physical;
  81	u64			physical_for_dev_replace;
  82	atomic_t		refs;
  83	struct {
  84		unsigned int	mirror_num:8;
  85		unsigned int	have_csum:1;
  86		unsigned int	io_error:1;
  87	};
  88	u8			csum[BTRFS_CSUM_SIZE];
  89
  90	struct scrub_recover	*recover;
  91};
  92
  93struct scrub_bio {
  94	int			index;
  95	struct scrub_ctx	*sctx;
  96	struct btrfs_device	*dev;
  97	struct bio		*bio;
  98	int			err;
  99	u64			logical;
 100	u64			physical;
 101#if SCRUB_PAGES_PER_WR_BIO >= SCRUB_PAGES_PER_RD_BIO
 102	struct scrub_page	*pagev[SCRUB_PAGES_PER_WR_BIO];
 103#else
 104	struct scrub_page	*pagev[SCRUB_PAGES_PER_RD_BIO];
 105#endif
 106	int			page_count;
 107	int			next_free;
 108	struct btrfs_work	work;
 109};
 110
 111struct scrub_block {
 112	struct scrub_page	*pagev[SCRUB_MAX_PAGES_PER_BLOCK];
 113	int			page_count;
 114	atomic_t		outstanding_pages;
 115	atomic_t		refs; /* free mem on transition to zero */
 116	struct scrub_ctx	*sctx;
 117	struct scrub_parity	*sparity;
 118	struct {
 119		unsigned int	header_error:1;
 120		unsigned int	checksum_error:1;
 121		unsigned int	no_io_error_seen:1;
 122		unsigned int	generation_error:1; /* also sets header_error */
 123
 124		/* The following is for the data used to check parity */
 125		/* It is for the data with checksum */
 126		unsigned int	data_corrected:1;
 127	};
 128	struct btrfs_work	work;
 129};
 130
 131/* Used for the chunks with parity stripe such RAID5/6 */
 132struct scrub_parity {
 133	struct scrub_ctx	*sctx;
 134
 135	struct btrfs_device	*scrub_dev;
 136
 137	u64			logic_start;
 138
 139	u64			logic_end;
 140
 141	int			nsectors;
 142
 143	int			stripe_len;
 144
 145	atomic_t		refs;
 146
 147	struct list_head	spages;
 148
 149	/* Work of parity check and repair */
 150	struct btrfs_work	work;
 151
 152	/* Mark the parity blocks which have data */
 153	unsigned long		*dbitmap;
 154
 155	/*
 156	 * Mark the parity blocks which have data, but errors happen when
 157	 * read data or check data
 158	 */
 159	unsigned long		*ebitmap;
 160
 161	unsigned long		bitmap[0];
 162};
 163
 164struct scrub_wr_ctx {
 165	struct scrub_bio *wr_curr_bio;
 166	struct btrfs_device *tgtdev;
 167	int pages_per_wr_bio; /* <= SCRUB_PAGES_PER_WR_BIO */
 168	atomic_t flush_all_writes;
 169	struct mutex wr_lock;
 170};
 171
 172struct scrub_ctx {
 173	struct scrub_bio	*bios[SCRUB_BIOS_PER_SCTX];
 174	struct btrfs_root	*dev_root;
 175	int			first_free;
 176	int			curr;
 177	atomic_t		bios_in_flight;
 178	atomic_t		workers_pending;
 179	spinlock_t		list_lock;
 180	wait_queue_head_t	list_wait;
 181	u16			csum_size;
 182	struct list_head	csum_list;
 183	atomic_t		cancel_req;
 184	int			readonly;
 185	int			pages_per_rd_bio;
 186	u32			sectorsize;
 187	u32			nodesize;
 188
 189	int			is_dev_replace;
 190	struct scrub_wr_ctx	wr_ctx;
 191
 192	/*
 193	 * statistics
 194	 */
 195	struct btrfs_scrub_progress stat;
 196	spinlock_t		stat_lock;
 197
 198	/*
 199	 * Use a ref counter to avoid use-after-free issues. Scrub workers
 200	 * decrement bios_in_flight and workers_pending and then do a wakeup
 201	 * on the list_wait wait queue. We must ensure the main scrub task
 202	 * doesn't free the scrub context before or while the workers are
 203	 * doing the wakeup() call.
 204	 */
 205	atomic_t                refs;
 206};
 207
 208struct scrub_fixup_nodatasum {
 209	struct scrub_ctx	*sctx;
 210	struct btrfs_device	*dev;
 211	u64			logical;
 212	struct btrfs_root	*root;
 213	struct btrfs_work	work;
 214	int			mirror_num;
 215};
 216
 217struct scrub_nocow_inode {
 218	u64			inum;
 219	u64			offset;
 220	u64			root;
 221	struct list_head	list;
 222};
 223
 224struct scrub_copy_nocow_ctx {
 225	struct scrub_ctx	*sctx;
 226	u64			logical;
 227	u64			len;
 228	int			mirror_num;
 229	u64			physical_for_dev_replace;
 230	struct list_head	inodes;
 231	struct btrfs_work	work;
 232};
 233
 234struct scrub_warning {
 235	struct btrfs_path	*path;
 236	u64			extent_item_size;
 
 
 237	const char		*errstr;
 238	sector_t		sector;
 239	u64			logical;
 240	struct btrfs_device	*dev;
 
 
 241};
 242
 243static void scrub_pending_bio_inc(struct scrub_ctx *sctx);
 244static void scrub_pending_bio_dec(struct scrub_ctx *sctx);
 245static void scrub_pending_trans_workers_inc(struct scrub_ctx *sctx);
 246static void scrub_pending_trans_workers_dec(struct scrub_ctx *sctx);
 247static int scrub_handle_errored_block(struct scrub_block *sblock_to_check);
 248static int scrub_setup_recheck_block(struct scrub_block *original_sblock,
 249				     struct scrub_block *sblocks_for_recheck);
 250static void scrub_recheck_block(struct btrfs_fs_info *fs_info,
 251				struct scrub_block *sblock,
 252				int retry_failed_mirror);
 253static void scrub_recheck_block_checksum(struct scrub_block *sblock);
 
 
 
 
 
 
 
 
 254static int scrub_repair_block_from_good_copy(struct scrub_block *sblock_bad,
 255					     struct scrub_block *sblock_good);
 
 256static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
 257					    struct scrub_block *sblock_good,
 258					    int page_num, int force_write);
 259static void scrub_write_block_to_dev_replace(struct scrub_block *sblock);
 260static int scrub_write_page_to_dev_replace(struct scrub_block *sblock,
 261					   int page_num);
 262static int scrub_checksum_data(struct scrub_block *sblock);
 263static int scrub_checksum_tree_block(struct scrub_block *sblock);
 264static int scrub_checksum_super(struct scrub_block *sblock);
 265static void scrub_block_get(struct scrub_block *sblock);
 266static void scrub_block_put(struct scrub_block *sblock);
 267static void scrub_page_get(struct scrub_page *spage);
 268static void scrub_page_put(struct scrub_page *spage);
 269static void scrub_parity_get(struct scrub_parity *sparity);
 270static void scrub_parity_put(struct scrub_parity *sparity);
 271static int scrub_add_page_to_rd_bio(struct scrub_ctx *sctx,
 272				    struct scrub_page *spage);
 273static int scrub_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
 274		       u64 physical, struct btrfs_device *dev, u64 flags,
 275		       u64 gen, int mirror_num, u8 *csum, int force,
 276		       u64 physical_for_dev_replace);
 277static void scrub_bio_end_io(struct bio *bio);
 278static void scrub_bio_end_io_worker(struct btrfs_work *work);
 279static void scrub_block_complete(struct scrub_block *sblock);
 280static void scrub_remap_extent(struct btrfs_fs_info *fs_info,
 281			       u64 extent_logical, u64 extent_len,
 282			       u64 *extent_physical,
 283			       struct btrfs_device **extent_dev,
 284			       int *extent_mirror_num);
 285static int scrub_setup_wr_ctx(struct scrub_ctx *sctx,
 286			      struct scrub_wr_ctx *wr_ctx,
 287			      struct btrfs_fs_info *fs_info,
 288			      struct btrfs_device *dev,
 289			      int is_dev_replace);
 290static void scrub_free_wr_ctx(struct scrub_wr_ctx *wr_ctx);
 291static int scrub_add_page_to_wr_bio(struct scrub_ctx *sctx,
 292				    struct scrub_page *spage);
 293static void scrub_wr_submit(struct scrub_ctx *sctx);
 294static void scrub_wr_bio_end_io(struct bio *bio);
 295static void scrub_wr_bio_end_io_worker(struct btrfs_work *work);
 296static int write_page_nocow(struct scrub_ctx *sctx,
 297			    u64 physical_for_dev_replace, struct page *page);
 298static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root,
 299				      struct scrub_copy_nocow_ctx *ctx);
 300static int copy_nocow_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
 301			    int mirror_num, u64 physical_for_dev_replace);
 302static void copy_nocow_pages_worker(struct btrfs_work *work);
 303static void __scrub_blocked_if_needed(struct btrfs_fs_info *fs_info);
 304static void scrub_blocked_if_needed(struct btrfs_fs_info *fs_info);
 305static void scrub_put_ctx(struct scrub_ctx *sctx);
 306
 307
 308static void scrub_pending_bio_inc(struct scrub_ctx *sctx)
 309{
 310	atomic_inc(&sctx->refs);
 311	atomic_inc(&sctx->bios_in_flight);
 312}
 313
 314static void scrub_pending_bio_dec(struct scrub_ctx *sctx)
 315{
 316	atomic_dec(&sctx->bios_in_flight);
 317	wake_up(&sctx->list_wait);
 318	scrub_put_ctx(sctx);
 319}
 320
 321static void __scrub_blocked_if_needed(struct btrfs_fs_info *fs_info)
 322{
 323	while (atomic_read(&fs_info->scrub_pause_req)) {
 324		mutex_unlock(&fs_info->scrub_lock);
 325		wait_event(fs_info->scrub_pause_wait,
 326		   atomic_read(&fs_info->scrub_pause_req) == 0);
 327		mutex_lock(&fs_info->scrub_lock);
 328	}
 329}
 330
 331static void scrub_pause_on(struct btrfs_fs_info *fs_info)
 332{
 333	atomic_inc(&fs_info->scrubs_paused);
 334	wake_up(&fs_info->scrub_pause_wait);
 335}
 336
 337static void scrub_pause_off(struct btrfs_fs_info *fs_info)
 338{
 339	mutex_lock(&fs_info->scrub_lock);
 340	__scrub_blocked_if_needed(fs_info);
 341	atomic_dec(&fs_info->scrubs_paused);
 342	mutex_unlock(&fs_info->scrub_lock);
 343
 344	wake_up(&fs_info->scrub_pause_wait);
 345}
 346
 347static void scrub_blocked_if_needed(struct btrfs_fs_info *fs_info)
 348{
 349	scrub_pause_on(fs_info);
 350	scrub_pause_off(fs_info);
 351}
 352
 353/*
 354 * used for workers that require transaction commits (i.e., for the
 355 * NOCOW case)
 356 */
 357static void scrub_pending_trans_workers_inc(struct scrub_ctx *sctx)
 358{
 359	struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;
 360
 361	atomic_inc(&sctx->refs);
 362	/*
 363	 * increment scrubs_running to prevent cancel requests from
 364	 * completing as long as a worker is running. we must also
 365	 * increment scrubs_paused to prevent deadlocking on pause
 366	 * requests used for transactions commits (as the worker uses a
 367	 * transaction context). it is safe to regard the worker
 368	 * as paused for all matters practical. effectively, we only
 369	 * avoid cancellation requests from completing.
 370	 */
 371	mutex_lock(&fs_info->scrub_lock);
 372	atomic_inc(&fs_info->scrubs_running);
 373	atomic_inc(&fs_info->scrubs_paused);
 374	mutex_unlock(&fs_info->scrub_lock);
 375
 376	/*
 377	 * check if @scrubs_running=@scrubs_paused condition
 378	 * inside wait_event() is not an atomic operation.
 379	 * which means we may inc/dec @scrub_running/paused
 380	 * at any time. Let's wake up @scrub_pause_wait as
 381	 * much as we can to let commit transaction blocked less.
 382	 */
 383	wake_up(&fs_info->scrub_pause_wait);
 384
 385	atomic_inc(&sctx->workers_pending);
 386}
 387
 388/* used for workers that require transaction commits */
 389static void scrub_pending_trans_workers_dec(struct scrub_ctx *sctx)
 390{
 391	struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;
 392
 393	/*
 394	 * see scrub_pending_trans_workers_inc() why we're pretending
 395	 * to be paused in the scrub counters
 396	 */
 397	mutex_lock(&fs_info->scrub_lock);
 398	atomic_dec(&fs_info->scrubs_running);
 399	atomic_dec(&fs_info->scrubs_paused);
 400	mutex_unlock(&fs_info->scrub_lock);
 401	atomic_dec(&sctx->workers_pending);
 402	wake_up(&fs_info->scrub_pause_wait);
 403	wake_up(&sctx->list_wait);
 404	scrub_put_ctx(sctx);
 405}
 406
 407static void scrub_free_csums(struct scrub_ctx *sctx)
 408{
 409	while (!list_empty(&sctx->csum_list)) {
 410		struct btrfs_ordered_sum *sum;
 411		sum = list_first_entry(&sctx->csum_list,
 412				       struct btrfs_ordered_sum, list);
 413		list_del(&sum->list);
 414		kfree(sum);
 415	}
 416}
 417
 418static noinline_for_stack void scrub_free_ctx(struct scrub_ctx *sctx)
 419{
 420	int i;
 421
 422	if (!sctx)
 423		return;
 424
 425	scrub_free_wr_ctx(&sctx->wr_ctx);
 426
 427	/* this can happen when scrub is cancelled */
 428	if (sctx->curr != -1) {
 429		struct scrub_bio *sbio = sctx->bios[sctx->curr];
 430
 431		for (i = 0; i < sbio->page_count; i++) {
 432			WARN_ON(!sbio->pagev[i]->page);
 
 433			scrub_block_put(sbio->pagev[i]->sblock);
 434		}
 435		bio_put(sbio->bio);
 436	}
 437
 438	for (i = 0; i < SCRUB_BIOS_PER_SCTX; ++i) {
 439		struct scrub_bio *sbio = sctx->bios[i];
 440
 441		if (!sbio)
 442			break;
 443		kfree(sbio);
 444	}
 445
 446	scrub_free_csums(sctx);
 447	kfree(sctx);
 448}
 449
 450static void scrub_put_ctx(struct scrub_ctx *sctx)
 451{
 452	if (atomic_dec_and_test(&sctx->refs))
 453		scrub_free_ctx(sctx);
 454}
 455
 456static noinline_for_stack
 457struct scrub_ctx *scrub_setup_ctx(struct btrfs_device *dev, int is_dev_replace)
 458{
 459	struct scrub_ctx *sctx;
 460	int		i;
 461	struct btrfs_fs_info *fs_info = dev->dev_root->fs_info;
 462	int ret;
 463
 464	sctx = kzalloc(sizeof(*sctx), GFP_KERNEL);
 465	if (!sctx)
 
 
 466		goto nomem;
 467	atomic_set(&sctx->refs, 1);
 468	sctx->is_dev_replace = is_dev_replace;
 469	sctx->pages_per_rd_bio = SCRUB_PAGES_PER_RD_BIO;
 470	sctx->curr = -1;
 471	sctx->dev_root = dev->dev_root;
 472	for (i = 0; i < SCRUB_BIOS_PER_SCTX; ++i) {
 473		struct scrub_bio *sbio;
 474
 475		sbio = kzalloc(sizeof(*sbio), GFP_KERNEL);
 476		if (!sbio)
 477			goto nomem;
 478		sctx->bios[i] = sbio;
 479
 480		sbio->index = i;
 481		sbio->sctx = sctx;
 482		sbio->page_count = 0;
 483		btrfs_init_work(&sbio->work, btrfs_scrub_helper,
 484				scrub_bio_end_io_worker, NULL, NULL);
 485
 486		if (i != SCRUB_BIOS_PER_SCTX - 1)
 487			sctx->bios[i]->next_free = i + 1;
 488		else
 489			sctx->bios[i]->next_free = -1;
 490	}
 491	sctx->first_free = 0;
 492	sctx->nodesize = dev->dev_root->nodesize;
 493	sctx->sectorsize = dev->dev_root->sectorsize;
 494	atomic_set(&sctx->bios_in_flight, 0);
 495	atomic_set(&sctx->workers_pending, 0);
 496	atomic_set(&sctx->cancel_req, 0);
 497	sctx->csum_size = btrfs_super_csum_size(fs_info->super_copy);
 498	INIT_LIST_HEAD(&sctx->csum_list);
 499
 500	spin_lock_init(&sctx->list_lock);
 501	spin_lock_init(&sctx->stat_lock);
 502	init_waitqueue_head(&sctx->list_wait);
 503
 504	ret = scrub_setup_wr_ctx(sctx, &sctx->wr_ctx, fs_info,
 505				 fs_info->dev_replace.tgtdev, is_dev_replace);
 506	if (ret) {
 507		scrub_free_ctx(sctx);
 508		return ERR_PTR(ret);
 509	}
 510	return sctx;
 
 
 
 
 
 
 
 
 
 
 
 
 
 511
 512nomem:
 513	scrub_free_ctx(sctx);
 514	return ERR_PTR(-ENOMEM);
 515}
 516
 517static int scrub_print_warning_inode(u64 inum, u64 offset, u64 root,
 518				     void *warn_ctx)
 519{
 520	u64 isize;
 521	u32 nlink;
 522	int ret;
 523	int i;
 524	struct extent_buffer *eb;
 525	struct btrfs_inode_item *inode_item;
 526	struct scrub_warning *swarn = warn_ctx;
 527	struct btrfs_fs_info *fs_info = swarn->dev->dev_root->fs_info;
 528	struct inode_fs_paths *ipath = NULL;
 529	struct btrfs_root *local_root;
 530	struct btrfs_key root_key;
 531	struct btrfs_key key;
 532
 533	root_key.objectid = root;
 534	root_key.type = BTRFS_ROOT_ITEM_KEY;
 535	root_key.offset = (u64)-1;
 536	local_root = btrfs_read_fs_root_no_name(fs_info, &root_key);
 537	if (IS_ERR(local_root)) {
 538		ret = PTR_ERR(local_root);
 539		goto err;
 540	}
 541
 542	/*
 543	 * this makes the path point to (inum INODE_ITEM ioff)
 544	 */
 545	key.objectid = inum;
 546	key.type = BTRFS_INODE_ITEM_KEY;
 547	key.offset = 0;
 548
 549	ret = btrfs_search_slot(NULL, local_root, &key, swarn->path, 0, 0);
 550	if (ret) {
 551		btrfs_release_path(swarn->path);
 552		goto err;
 553	}
 554
 555	eb = swarn->path->nodes[0];
 556	inode_item = btrfs_item_ptr(eb, swarn->path->slots[0],
 557					struct btrfs_inode_item);
 558	isize = btrfs_inode_size(eb, inode_item);
 559	nlink = btrfs_inode_nlink(eb, inode_item);
 560	btrfs_release_path(swarn->path);
 561
 562	ipath = init_ipath(4096, local_root, swarn->path);
 563	if (IS_ERR(ipath)) {
 564		ret = PTR_ERR(ipath);
 565		ipath = NULL;
 566		goto err;
 567	}
 568	ret = paths_from_inode(inum, ipath);
 569
 570	if (ret < 0)
 571		goto err;
 572
 573	/*
 574	 * we deliberately ignore the bit ipath might have been too small to
 575	 * hold all of the paths here
 576	 */
 577	for (i = 0; i < ipath->fspath->elem_cnt; ++i)
 578		btrfs_warn_in_rcu(fs_info, "%s at logical %llu on dev "
 579			"%s, sector %llu, root %llu, inode %llu, offset %llu, "
 580			"length %llu, links %u (path: %s)", swarn->errstr,
 581			swarn->logical, rcu_str_deref(swarn->dev->name),
 582			(unsigned long long)swarn->sector, root, inum, offset,
 583			min(isize - offset, (u64)PAGE_SIZE), nlink,
 584			(char *)(unsigned long)ipath->fspath->val[i]);
 585
 586	free_ipath(ipath);
 587	return 0;
 588
 589err:
 590	btrfs_warn_in_rcu(fs_info, "%s at logical %llu on dev "
 591		"%s, sector %llu, root %llu, inode %llu, offset %llu: path "
 592		"resolving failed with ret=%d", swarn->errstr,
 593		swarn->logical, rcu_str_deref(swarn->dev->name),
 594		(unsigned long long)swarn->sector, root, inum, offset, ret);
 595
 596	free_ipath(ipath);
 597	return 0;
 598}
 599
 600static void scrub_print_warning(const char *errstr, struct scrub_block *sblock)
 601{
 602	struct btrfs_device *dev;
 603	struct btrfs_fs_info *fs_info;
 604	struct btrfs_path *path;
 605	struct btrfs_key found_key;
 606	struct extent_buffer *eb;
 607	struct btrfs_extent_item *ei;
 608	struct scrub_warning swarn;
 609	unsigned long ptr = 0;
 610	u64 extent_item_pos;
 611	u64 flags = 0;
 612	u64 ref_root;
 613	u32 item_size;
 614	u8 ref_level = 0;
 615	int ret;
 616
 617	WARN_ON(sblock->page_count < 1);
 618	dev = sblock->pagev[0]->dev;
 619	fs_info = sblock->sctx->dev_root->fs_info;
 
 620
 621	path = btrfs_alloc_path();
 622	if (!path)
 623		return;
 624
 625	swarn.sector = (sblock->pagev[0]->physical) >> 9;
 626	swarn.logical = sblock->pagev[0]->logical;
 
 
 
 627	swarn.errstr = errstr;
 628	swarn.dev = NULL;
 
 
 629
 630	ret = extent_from_logical(fs_info, swarn.logical, path, &found_key,
 631				  &flags);
 
 
 632	if (ret < 0)
 633		goto out;
 634
 635	extent_item_pos = swarn.logical - found_key.objectid;
 636	swarn.extent_item_size = found_key.offset;
 637
 638	eb = path->nodes[0];
 639	ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
 640	item_size = btrfs_item_size_nr(eb, path->slots[0]);
 
 641
 642	if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
 643		do {
 644			ret = tree_backref_for_extent(&ptr, eb, &found_key, ei,
 645						      item_size, &ref_root,
 646						      &ref_level);
 647			btrfs_warn_in_rcu(fs_info,
 648				"%s at logical %llu on dev %s, "
 649				"sector %llu: metadata %s (level %d) in tree "
 650				"%llu", errstr, swarn.logical,
 651				rcu_str_deref(dev->name),
 652				(unsigned long long)swarn.sector,
 653				ref_level ? "node" : "leaf",
 654				ret < 0 ? -1 : ref_level,
 655				ret < 0 ? -1 : ref_root);
 656		} while (ret != 1);
 657		btrfs_release_path(path);
 658	} else {
 659		btrfs_release_path(path);
 660		swarn.path = path;
 661		swarn.dev = dev;
 662		iterate_extent_inodes(fs_info, found_key.objectid,
 663					extent_item_pos, 1,
 664					scrub_print_warning_inode, &swarn);
 665	}
 666
 667out:
 668	btrfs_free_path(path);
 
 
 669}
 670
 671static int scrub_fixup_readpage(u64 inum, u64 offset, u64 root, void *fixup_ctx)
 672{
 673	struct page *page = NULL;
 674	unsigned long index;
 675	struct scrub_fixup_nodatasum *fixup = fixup_ctx;
 676	int ret;
 677	int corrected = 0;
 678	struct btrfs_key key;
 679	struct inode *inode = NULL;
 680	struct btrfs_fs_info *fs_info;
 681	u64 end = offset + PAGE_SIZE - 1;
 682	struct btrfs_root *local_root;
 683	int srcu_index;
 684
 685	key.objectid = root;
 686	key.type = BTRFS_ROOT_ITEM_KEY;
 687	key.offset = (u64)-1;
 688
 689	fs_info = fixup->root->fs_info;
 690	srcu_index = srcu_read_lock(&fs_info->subvol_srcu);
 691
 692	local_root = btrfs_read_fs_root_no_name(fs_info, &key);
 693	if (IS_ERR(local_root)) {
 694		srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
 695		return PTR_ERR(local_root);
 696	}
 697
 698	key.type = BTRFS_INODE_ITEM_KEY;
 699	key.objectid = inum;
 700	key.offset = 0;
 701	inode = btrfs_iget(fs_info->sb, &key, local_root, NULL);
 702	srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
 703	if (IS_ERR(inode))
 704		return PTR_ERR(inode);
 705
 706	index = offset >> PAGE_SHIFT;
 707
 708	page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
 709	if (!page) {
 710		ret = -ENOMEM;
 711		goto out;
 712	}
 713
 714	if (PageUptodate(page)) {
 
 715		if (PageDirty(page)) {
 716			/*
 717			 * we need to write the data to the defect sector. the
 718			 * data that was in that sector is not in memory,
 719			 * because the page was modified. we must not write the
 720			 * modified page to that sector.
 721			 *
 722			 * TODO: what could be done here: wait for the delalloc
 723			 *       runner to write out that page (might involve
 724			 *       COW) and see whether the sector is still
 725			 *       referenced afterwards.
 726			 *
 727			 * For the meantime, we'll treat this error
 728			 * incorrectable, although there is a chance that a
 729			 * later scrub will find the bad sector again and that
 730			 * there's no dirty page in memory, then.
 731			 */
 732			ret = -EIO;
 733			goto out;
 734		}
 735		ret = repair_io_failure(inode, offset, PAGE_SIZE,
 
 736					fixup->logical, page,
 737					offset - page_offset(page),
 738					fixup->mirror_num);
 739		unlock_page(page);
 740		corrected = !ret;
 741	} else {
 742		/*
 743		 * we need to get good data first. the general readpage path
 744		 * will call repair_io_failure for us, we just have to make
 745		 * sure we read the bad mirror.
 746		 */
 747		ret = set_extent_bits(&BTRFS_I(inode)->io_tree, offset, end,
 748					EXTENT_DAMAGED, GFP_NOFS);
 749		if (ret) {
 750			/* set_extent_bits should give proper error */
 751			WARN_ON(ret > 0);
 752			if (ret > 0)
 753				ret = -EFAULT;
 754			goto out;
 755		}
 756
 757		ret = extent_read_full_page(&BTRFS_I(inode)->io_tree, page,
 758						btrfs_get_extent,
 759						fixup->mirror_num);
 760		wait_on_page_locked(page);
 761
 762		corrected = !test_range_bit(&BTRFS_I(inode)->io_tree, offset,
 763						end, EXTENT_DAMAGED, 0, NULL);
 764		if (!corrected)
 765			clear_extent_bits(&BTRFS_I(inode)->io_tree, offset, end,
 766						EXTENT_DAMAGED, GFP_NOFS);
 767	}
 768
 769out:
 770	if (page)
 771		put_page(page);
 772
 773	iput(inode);
 774
 775	if (ret < 0)
 776		return ret;
 777
 778	if (ret == 0 && corrected) {
 779		/*
 780		 * we only need to call readpage for one of the inodes belonging
 781		 * to this extent. so make iterate_extent_inodes stop
 782		 */
 783		return 1;
 784	}
 785
 786	return -EIO;
 787}
 788
 789static void scrub_fixup_nodatasum(struct btrfs_work *work)
 790{
 791	int ret;
 792	struct scrub_fixup_nodatasum *fixup;
 793	struct scrub_ctx *sctx;
 794	struct btrfs_trans_handle *trans = NULL;
 
 795	struct btrfs_path *path;
 796	int uncorrectable = 0;
 797
 798	fixup = container_of(work, struct scrub_fixup_nodatasum, work);
 799	sctx = fixup->sctx;
 
 800
 801	path = btrfs_alloc_path();
 802	if (!path) {
 803		spin_lock(&sctx->stat_lock);
 804		++sctx->stat.malloc_errors;
 805		spin_unlock(&sctx->stat_lock);
 806		uncorrectable = 1;
 807		goto out;
 808	}
 809
 810	trans = btrfs_join_transaction(fixup->root);
 811	if (IS_ERR(trans)) {
 812		uncorrectable = 1;
 813		goto out;
 814	}
 815
 816	/*
 817	 * the idea is to trigger a regular read through the standard path. we
 818	 * read a page from the (failed) logical address by specifying the
 819	 * corresponding copynum of the failed sector. thus, that readpage is
 820	 * expected to fail.
 821	 * that is the point where on-the-fly error correction will kick in
 822	 * (once it's finished) and rewrite the failed sector if a good copy
 823	 * can be found.
 824	 */
 825	ret = iterate_inodes_from_logical(fixup->logical, fixup->root->fs_info,
 826						path, scrub_fixup_readpage,
 827						fixup);
 828	if (ret < 0) {
 829		uncorrectable = 1;
 830		goto out;
 831	}
 832	WARN_ON(ret != 1);
 833
 834	spin_lock(&sctx->stat_lock);
 835	++sctx->stat.corrected_errors;
 836	spin_unlock(&sctx->stat_lock);
 837
 838out:
 839	if (trans && !IS_ERR(trans))
 840		btrfs_end_transaction(trans, fixup->root);
 841	if (uncorrectable) {
 842		spin_lock(&sctx->stat_lock);
 843		++sctx->stat.uncorrectable_errors;
 844		spin_unlock(&sctx->stat_lock);
 845		btrfs_dev_replace_stats_inc(
 846			&sctx->dev_root->fs_info->dev_replace.
 847			num_uncorrectable_read_errors);
 848		btrfs_err_rl_in_rcu(sctx->dev_root->fs_info,
 849		    "unable to fixup (nodatasum) error at logical %llu on dev %s",
 850			fixup->logical, rcu_str_deref(fixup->dev->name));
 851	}
 852
 853	btrfs_free_path(path);
 854	kfree(fixup);
 855
 856	scrub_pending_trans_workers_dec(sctx);
 857}
 858
 859static inline void scrub_get_recover(struct scrub_recover *recover)
 860{
 861	atomic_inc(&recover->refs);
 862}
 863
 864static inline void scrub_put_recover(struct scrub_recover *recover)
 865{
 866	if (atomic_dec_and_test(&recover->refs)) {
 867		btrfs_put_bbio(recover->bbio);
 868		kfree(recover);
 869	}
 870}
 871
 872/*
 873 * scrub_handle_errored_block gets called when either verification of the
 874 * pages failed or the bio failed to read, e.g. with EIO. In the latter
 875 * case, this function handles all pages in the bio, even though only one
 876 * may be bad.
 877 * The goal of this function is to repair the errored block by using the
 878 * contents of one of the mirrors.
 879 */
 880static int scrub_handle_errored_block(struct scrub_block *sblock_to_check)
 881{
 882	struct scrub_ctx *sctx = sblock_to_check->sctx;
 883	struct btrfs_device *dev;
 884	struct btrfs_fs_info *fs_info;
 885	u64 length;
 886	u64 logical;
 
 887	unsigned int failed_mirror_index;
 888	unsigned int is_metadata;
 889	unsigned int have_csum;
 
 890	struct scrub_block *sblocks_for_recheck; /* holds one for each mirror */
 891	struct scrub_block *sblock_bad;
 892	int ret;
 893	int mirror_index;
 894	int page_num;
 895	int success;
 896	static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
 897				      DEFAULT_RATELIMIT_BURST);
 898
 899	BUG_ON(sblock_to_check->page_count < 1);
 900	fs_info = sctx->dev_root->fs_info;
 901	if (sblock_to_check->pagev[0]->flags & BTRFS_EXTENT_FLAG_SUPER) {
 902		/*
 903		 * if we find an error in a super block, we just report it.
 904		 * They will get written with the next transaction commit
 905		 * anyway
 906		 */
 907		spin_lock(&sctx->stat_lock);
 908		++sctx->stat.super_errors;
 909		spin_unlock(&sctx->stat_lock);
 910		return 0;
 911	}
 912	length = sblock_to_check->page_count * PAGE_SIZE;
 913	logical = sblock_to_check->pagev[0]->logical;
 914	BUG_ON(sblock_to_check->pagev[0]->mirror_num < 1);
 915	failed_mirror_index = sblock_to_check->pagev[0]->mirror_num - 1;
 916	is_metadata = !(sblock_to_check->pagev[0]->flags &
 
 917			BTRFS_EXTENT_FLAG_DATA);
 918	have_csum = sblock_to_check->pagev[0]->have_csum;
 919	dev = sblock_to_check->pagev[0]->dev;
 920
 921	if (sctx->is_dev_replace && !is_metadata && !have_csum) {
 922		sblocks_for_recheck = NULL;
 923		goto nodatasum_case;
 924	}
 925
 926	/*
 927	 * read all mirrors one after the other. This includes to
 928	 * re-read the extent or metadata block that failed (that was
 929	 * the cause that this fixup code is called) another time,
 930	 * page by page this time in order to know which pages
 931	 * caused I/O errors and which ones are good (for all mirrors).
 932	 * It is the goal to handle the situation when more than one
 933	 * mirror contains I/O errors, but the errors do not
 934	 * overlap, i.e. the data can be repaired by selecting the
 935	 * pages from those mirrors without I/O error on the
 936	 * particular pages. One example (with blocks >= 2 * PAGE_SIZE)
 937	 * would be that mirror #1 has an I/O error on the first page,
 938	 * the second page is good, and mirror #2 has an I/O error on
 939	 * the second page, but the first page is good.
 940	 * Then the first page of the first mirror can be repaired by
 941	 * taking the first page of the second mirror, and the
 942	 * second page of the second mirror can be repaired by
 943	 * copying the contents of the 2nd page of the 1st mirror.
 944	 * One more note: if the pages of one mirror contain I/O
 945	 * errors, the checksum cannot be verified. In order to get
 946	 * the best data for repairing, the first attempt is to find
 947	 * a mirror without I/O errors and with a validated checksum.
 948	 * Only if this is not possible, the pages are picked from
 949	 * mirrors with I/O errors without considering the checksum.
 950	 * If the latter is the case, at the end, the checksum of the
 951	 * repaired area is verified in order to correctly maintain
 952	 * the statistics.
 953	 */
 954
 955	sblocks_for_recheck = kcalloc(BTRFS_MAX_MIRRORS,
 956				      sizeof(*sblocks_for_recheck), GFP_NOFS);
 
 957	if (!sblocks_for_recheck) {
 958		spin_lock(&sctx->stat_lock);
 959		sctx->stat.malloc_errors++;
 960		sctx->stat.read_errors++;
 961		sctx->stat.uncorrectable_errors++;
 962		spin_unlock(&sctx->stat_lock);
 963		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
 
 964		goto out;
 965	}
 966
 967	/* setup the context, map the logical blocks and alloc the pages */
 968	ret = scrub_setup_recheck_block(sblock_to_check, sblocks_for_recheck);
 
 969	if (ret) {
 970		spin_lock(&sctx->stat_lock);
 971		sctx->stat.read_errors++;
 972		sctx->stat.uncorrectable_errors++;
 973		spin_unlock(&sctx->stat_lock);
 974		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
 
 975		goto out;
 976	}
 977	BUG_ON(failed_mirror_index >= BTRFS_MAX_MIRRORS);
 978	sblock_bad = sblocks_for_recheck + failed_mirror_index;
 979
 980	/* build and submit the bios for the failed mirror, check checksums */
 981	scrub_recheck_block(fs_info, sblock_bad, 1);
 
 
 
 
 
 
 
 
 
 
 982
 983	if (!sblock_bad->header_error && !sblock_bad->checksum_error &&
 984	    sblock_bad->no_io_error_seen) {
 985		/*
 986		 * the error disappeared after reading page by page, or
 987		 * the area was part of a huge bio and other parts of the
 988		 * bio caused I/O errors, or the block layer merged several
 989		 * read requests into one and the error is caused by a
 990		 * different bio (usually one of the two latter cases is
 991		 * the cause)
 992		 */
 993		spin_lock(&sctx->stat_lock);
 994		sctx->stat.unverified_errors++;
 995		sblock_to_check->data_corrected = 1;
 996		spin_unlock(&sctx->stat_lock);
 997
 998		if (sctx->is_dev_replace)
 999			scrub_write_block_to_dev_replace(sblock_bad);
1000		goto out;
1001	}
1002
1003	if (!sblock_bad->no_io_error_seen) {
1004		spin_lock(&sctx->stat_lock);
1005		sctx->stat.read_errors++;
1006		spin_unlock(&sctx->stat_lock);
1007		if (__ratelimit(&_rs))
1008			scrub_print_warning("i/o error", sblock_to_check);
1009		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
 
1010	} else if (sblock_bad->checksum_error) {
1011		spin_lock(&sctx->stat_lock);
1012		sctx->stat.csum_errors++;
1013		spin_unlock(&sctx->stat_lock);
1014		if (__ratelimit(&_rs))
1015			scrub_print_warning("checksum error", sblock_to_check);
1016		btrfs_dev_stat_inc_and_print(dev,
1017					     BTRFS_DEV_STAT_CORRUPTION_ERRS);
1018	} else if (sblock_bad->header_error) {
1019		spin_lock(&sctx->stat_lock);
1020		sctx->stat.verify_errors++;
1021		spin_unlock(&sctx->stat_lock);
1022		if (__ratelimit(&_rs))
1023			scrub_print_warning("checksum/header error",
1024					    sblock_to_check);
1025		if (sblock_bad->generation_error)
1026			btrfs_dev_stat_inc_and_print(dev,
1027				BTRFS_DEV_STAT_GENERATION_ERRS);
1028		else
1029			btrfs_dev_stat_inc_and_print(dev,
1030				BTRFS_DEV_STAT_CORRUPTION_ERRS);
1031	}
1032
1033	if (sctx->readonly) {
1034		ASSERT(!sctx->is_dev_replace);
1035		goto out;
1036	}
1037
1038	if (!is_metadata && !have_csum) {
1039		struct scrub_fixup_nodatasum *fixup_nodatasum;
1040
1041		WARN_ON(sctx->is_dev_replace);
1042
1043nodatasum_case:
1044
1045		/*
1046		 * !is_metadata and !have_csum, this means that the data
1047		 * might not be COW'ed, that it might be modified
1048		 * concurrently. The general strategy to work on the
1049		 * commit root does not help in the case when COW is not
1050		 * used.
1051		 */
1052		fixup_nodatasum = kzalloc(sizeof(*fixup_nodatasum), GFP_NOFS);
1053		if (!fixup_nodatasum)
1054			goto did_not_correct_error;
1055		fixup_nodatasum->sctx = sctx;
1056		fixup_nodatasum->dev = dev;
1057		fixup_nodatasum->logical = logical;
1058		fixup_nodatasum->root = fs_info->extent_root;
1059		fixup_nodatasum->mirror_num = failed_mirror_index + 1;
1060		scrub_pending_trans_workers_inc(sctx);
1061		btrfs_init_work(&fixup_nodatasum->work, btrfs_scrub_helper,
1062				scrub_fixup_nodatasum, NULL, NULL);
1063		btrfs_queue_work(fs_info->scrub_workers,
1064				 &fixup_nodatasum->work);
 
 
 
 
 
 
 
 
 
 
 
 
1065		goto out;
1066	}
1067
1068	/*
1069	 * now build and submit the bios for the other mirrors, check
1070	 * checksums.
1071	 * First try to pick the mirror which is completely without I/O
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1072	 * errors and also does not have a checksum error.
1073	 * If one is found, and if a checksum is present, the full block
1074	 * that is known to contain an error is rewritten. Afterwards
1075	 * the block is known to be corrected.
1076	 * If a mirror is found which is completely correct, and no
1077	 * checksum is present, only those pages are rewritten that had
1078	 * an I/O error in the block to be repaired, since it cannot be
1079	 * determined, which copy of the other pages is better (and it
1080	 * could happen otherwise that a correct page would be
1081	 * overwritten by a bad one).
1082	 */
1083	for (mirror_index = 0;
1084	     mirror_index < BTRFS_MAX_MIRRORS &&
1085	     sblocks_for_recheck[mirror_index].page_count > 0;
1086	     mirror_index++) {
1087		struct scrub_block *sblock_other;
1088
1089		if (mirror_index == failed_mirror_index)
1090			continue;
1091		sblock_other = sblocks_for_recheck + mirror_index;
1092
1093		/* build and submit the bios, check checksums */
1094		scrub_recheck_block(fs_info, sblock_other, 0);
1095
1096		if (!sblock_other->header_error &&
1097		    !sblock_other->checksum_error &&
1098		    sblock_other->no_io_error_seen) {
1099			if (sctx->is_dev_replace) {
1100				scrub_write_block_to_dev_replace(sblock_other);
 
 
 
 
1101				goto corrected_error;
1102			} else {
1103				ret = scrub_repair_block_from_good_copy(
1104						sblock_bad, sblock_other);
1105				if (!ret)
1106					goto corrected_error;
1107			}
1108		}
1109	}
1110
1111	if (sblock_bad->no_io_error_seen && !sctx->is_dev_replace)
1112		goto did_not_correct_error;
1113
1114	/*
1115	 * In case of I/O errors in the area that is supposed to be
1116	 * repaired, continue by picking good copies of those pages.
1117	 * Select the good pages from mirrors to rewrite bad pages from
1118	 * the area to fix. Afterwards verify the checksum of the block
1119	 * that is supposed to be repaired. This verification step is
1120	 * only done for the purpose of statistic counting and for the
1121	 * final scrub report, whether errors remain.
1122	 * A perfect algorithm could make use of the checksum and try
1123	 * all possible combinations of pages from the different mirrors
1124	 * until the checksum verification succeeds. For example, when
1125	 * the 2nd page of mirror #1 faces I/O errors, and the 2nd page
1126	 * of mirror #2 is readable but the final checksum test fails,
1127	 * then the 2nd page of mirror #3 could be tried, whether now
1128	 * the final checksum succeedes. But this would be a rare
1129	 * exception and is therefore not implemented. At least it is
1130	 * avoided that the good copy is overwritten.
1131	 * A more useful improvement would be to pick the sectors
1132	 * without I/O error based on sector sizes (512 bytes on legacy
1133	 * disks) instead of on PAGE_SIZE. Then maybe 512 byte of one
1134	 * mirror could be repaired by taking 512 byte of a different
1135	 * mirror, even if other 512 byte sectors in the same PAGE_SIZE
1136	 * area are unreadable.
1137	 */
 
 
 
 
 
1138	success = 1;
1139	for (page_num = 0; page_num < sblock_bad->page_count;
1140	     page_num++) {
1141		struct scrub_page *page_bad = sblock_bad->pagev[page_num];
1142		struct scrub_block *sblock_other = NULL;
1143
1144		/* skip no-io-error page in scrub */
1145		if (!page_bad->io_error && !sctx->is_dev_replace)
1146			continue;
1147
1148		/* try to find no-io-error page in mirrors */
1149		if (page_bad->io_error) {
1150			for (mirror_index = 0;
1151			     mirror_index < BTRFS_MAX_MIRRORS &&
1152			     sblocks_for_recheck[mirror_index].page_count > 0;
1153			     mirror_index++) {
1154				if (!sblocks_for_recheck[mirror_index].
1155				    pagev[page_num]->io_error) {
1156					sblock_other = sblocks_for_recheck +
1157						       mirror_index;
1158					break;
 
 
 
 
1159				}
1160			}
1161			if (!sblock_other)
1162				success = 0;
1163		}
1164
1165		if (sctx->is_dev_replace) {
1166			/*
1167			 * did not find a mirror to fetch the page
1168			 * from. scrub_write_page_to_dev_replace()
1169			 * handles this case (page->io_error), by
1170			 * filling the block with zeros before
1171			 * submitting the write request
1172			 */
1173			if (!sblock_other)
1174				sblock_other = sblock_bad;
1175
1176			if (scrub_write_page_to_dev_replace(sblock_other,
1177							    page_num) != 0) {
1178				btrfs_dev_replace_stats_inc(
1179					&sctx->dev_root->
1180					fs_info->dev_replace.
1181					num_write_errors);
1182				success = 0;
1183			}
1184		} else if (sblock_other) {
1185			ret = scrub_repair_page_from_good_copy(sblock_bad,
1186							       sblock_other,
1187							       page_num, 0);
1188			if (0 == ret)
1189				page_bad->io_error = 0;
1190			else
1191				success = 0;
1192		}
1193	}
1194
1195	if (success && !sctx->is_dev_replace) {
1196		if (is_metadata || have_csum) {
1197			/*
1198			 * need to verify the checksum now that all
1199			 * sectors on disk are repaired (the write
1200			 * request for data to be repaired is on its way).
1201			 * Just be lazy and use scrub_recheck_block()
1202			 * which re-reads the data before the checksum
1203			 * is verified, but most likely the data comes out
1204			 * of the page cache.
1205			 */
1206			scrub_recheck_block(fs_info, sblock_bad, 1);
1207			if (!sblock_bad->header_error &&
 
 
1208			    !sblock_bad->checksum_error &&
1209			    sblock_bad->no_io_error_seen)
1210				goto corrected_error;
1211			else
1212				goto did_not_correct_error;
1213		} else {
1214corrected_error:
1215			spin_lock(&sctx->stat_lock);
1216			sctx->stat.corrected_errors++;
1217			sblock_to_check->data_corrected = 1;
1218			spin_unlock(&sctx->stat_lock);
1219			btrfs_err_rl_in_rcu(fs_info,
1220				"fixed up error at logical %llu on dev %s",
1221				logical, rcu_str_deref(dev->name));
1222		}
1223	} else {
1224did_not_correct_error:
1225		spin_lock(&sctx->stat_lock);
1226		sctx->stat.uncorrectable_errors++;
1227		spin_unlock(&sctx->stat_lock);
1228		btrfs_err_rl_in_rcu(fs_info,
1229			"unable to fixup (regular) error at logical %llu on dev %s",
1230			logical, rcu_str_deref(dev->name));
 
1231	}
1232
1233out:
1234	if (sblocks_for_recheck) {
1235		for (mirror_index = 0; mirror_index < BTRFS_MAX_MIRRORS;
1236		     mirror_index++) {
1237			struct scrub_block *sblock = sblocks_for_recheck +
1238						     mirror_index;
1239			struct scrub_recover *recover;
1240			int page_index;
1241
1242			for (page_index = 0; page_index < sblock->page_count;
1243			     page_index++) {
1244				sblock->pagev[page_index]->sblock = NULL;
1245				recover = sblock->pagev[page_index]->recover;
1246				if (recover) {
1247					scrub_put_recover(recover);
1248					sblock->pagev[page_index]->recover =
1249									NULL;
1250				}
1251				scrub_page_put(sblock->pagev[page_index]);
1252			}
1253		}
1254		kfree(sblocks_for_recheck);
1255	}
1256
1257	return 0;
1258}
1259
1260static inline int scrub_nr_raid_mirrors(struct btrfs_bio *bbio)
1261{
1262	if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID5)
1263		return 2;
1264	else if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID6)
1265		return 3;
1266	else
1267		return (int)bbio->num_stripes;
1268}
1269
1270static inline void scrub_stripe_index_and_offset(u64 logical, u64 map_type,
1271						 u64 *raid_map,
1272						 u64 mapped_length,
1273						 int nstripes, int mirror,
1274						 int *stripe_index,
1275						 u64 *stripe_offset)
1276{
1277	int i;
1278
1279	if (map_type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
1280		/* RAID5/6 */
1281		for (i = 0; i < nstripes; i++) {
1282			if (raid_map[i] == RAID6_Q_STRIPE ||
1283			    raid_map[i] == RAID5_P_STRIPE)
1284				continue;
1285
1286			if (logical >= raid_map[i] &&
1287			    logical < raid_map[i] + mapped_length)
1288				break;
1289		}
1290
1291		*stripe_index = i;
1292		*stripe_offset = logical - raid_map[i];
1293	} else {
1294		/* The other RAID type */
1295		*stripe_index = mirror;
1296		*stripe_offset = 0;
1297	}
1298}
1299
1300static int scrub_setup_recheck_block(struct scrub_block *original_sblock,
1301				     struct scrub_block *sblocks_for_recheck)
1302{
1303	struct scrub_ctx *sctx = original_sblock->sctx;
1304	struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;
1305	u64 length = original_sblock->page_count * PAGE_SIZE;
1306	u64 logical = original_sblock->pagev[0]->logical;
1307	u64 generation = original_sblock->pagev[0]->generation;
1308	u64 flags = original_sblock->pagev[0]->flags;
1309	u64 have_csum = original_sblock->pagev[0]->have_csum;
1310	struct scrub_recover *recover;
1311	struct btrfs_bio *bbio;
1312	u64 sublen;
1313	u64 mapped_length;
1314	u64 stripe_offset;
1315	int stripe_index;
1316	int page_index = 0;
1317	int mirror_index;
1318	int nmirrors;
1319	int ret;
1320
1321	/*
1322	 * note: the two members refs and outstanding_pages
1323	 * are not used (and not set) in the blocks that are used for
1324	 * the recheck procedure
1325	 */
1326
 
1327	while (length > 0) {
1328		sublen = min_t(u64, length, PAGE_SIZE);
1329		mapped_length = sublen;
1330		bbio = NULL;
1331
1332		/*
1333		 * with a length of PAGE_SIZE, each returned stripe
1334		 * represents one mirror
1335		 */
1336		ret = btrfs_map_sblock(fs_info, REQ_GET_READ_MIRRORS, logical,
1337				       &mapped_length, &bbio, 0, 1);
1338		if (ret || !bbio || mapped_length < sublen) {
1339			btrfs_put_bbio(bbio);
1340			return -EIO;
1341		}
1342
1343		recover = kzalloc(sizeof(struct scrub_recover), GFP_NOFS);
1344		if (!recover) {
1345			btrfs_put_bbio(bbio);
1346			return -ENOMEM;
1347		}
1348
1349		atomic_set(&recover->refs, 1);
1350		recover->bbio = bbio;
1351		recover->map_length = mapped_length;
1352
1353		BUG_ON(page_index >= SCRUB_PAGES_PER_RD_BIO);
1354
1355		nmirrors = min(scrub_nr_raid_mirrors(bbio), BTRFS_MAX_MIRRORS);
1356
1357		for (mirror_index = 0; mirror_index < nmirrors;
1358		     mirror_index++) {
1359			struct scrub_block *sblock;
1360			struct scrub_page *page;
1361
1362			sblock = sblocks_for_recheck + mirror_index;
1363			sblock->sctx = sctx;
1364
1365			page = kzalloc(sizeof(*page), GFP_NOFS);
1366			if (!page) {
1367leave_nomem:
1368				spin_lock(&sctx->stat_lock);
1369				sctx->stat.malloc_errors++;
1370				spin_unlock(&sctx->stat_lock);
1371				scrub_put_recover(recover);
1372				return -ENOMEM;
1373			}
1374			scrub_page_get(page);
1375			sblock->pagev[page_index] = page;
1376			page->sblock = sblock;
1377			page->flags = flags;
1378			page->generation = generation;
1379			page->logical = logical;
1380			page->have_csum = have_csum;
1381			if (have_csum)
1382				memcpy(page->csum,
1383				       original_sblock->pagev[0]->csum,
1384				       sctx->csum_size);
1385
1386			scrub_stripe_index_and_offset(logical,
1387						      bbio->map_type,
1388						      bbio->raid_map,
1389						      mapped_length,
1390						      bbio->num_stripes -
1391						      bbio->num_tgtdevs,
1392						      mirror_index,
1393						      &stripe_index,
1394						      &stripe_offset);
1395			page->physical = bbio->stripes[stripe_index].physical +
1396					 stripe_offset;
1397			page->dev = bbio->stripes[stripe_index].dev;
1398
1399			BUG_ON(page_index >= original_sblock->page_count);
1400			page->physical_for_dev_replace =
1401				original_sblock->pagev[page_index]->
1402				physical_for_dev_replace;
1403			/* for missing devices, dev->bdev is NULL */
 
1404			page->mirror_num = mirror_index + 1;
1405			sblock->page_count++;
1406			page->page = alloc_page(GFP_NOFS);
1407			if (!page->page)
1408				goto leave_nomem;
1409
1410			scrub_get_recover(recover);
1411			page->recover = recover;
 
 
1412		}
1413		scrub_put_recover(recover);
1414		length -= sublen;
1415		logical += sublen;
1416		page_index++;
1417	}
1418
1419	return 0;
1420}
1421
1422struct scrub_bio_ret {
1423	struct completion event;
1424	int error;
1425};
1426
1427static void scrub_bio_wait_endio(struct bio *bio)
1428{
1429	struct scrub_bio_ret *ret = bio->bi_private;
1430
1431	ret->error = bio->bi_error;
1432	complete(&ret->event);
1433}
1434
1435static inline int scrub_is_page_on_raid56(struct scrub_page *page)
1436{
1437	return page->recover &&
1438	       (page->recover->bbio->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK);
1439}
1440
1441static int scrub_submit_raid56_bio_wait(struct btrfs_fs_info *fs_info,
1442					struct bio *bio,
1443					struct scrub_page *page)
1444{
1445	struct scrub_bio_ret done;
1446	int ret;
1447
1448	init_completion(&done.event);
1449	done.error = 0;
1450	bio->bi_iter.bi_sector = page->logical >> 9;
1451	bio->bi_private = &done;
1452	bio->bi_end_io = scrub_bio_wait_endio;
1453
1454	ret = raid56_parity_recover(fs_info->fs_root, bio, page->recover->bbio,
1455				    page->recover->map_length,
1456				    page->mirror_num, 0);
1457	if (ret)
1458		return ret;
1459
1460	wait_for_completion(&done.event);
1461	if (done.error)
1462		return -EIO;
1463
1464	return 0;
1465}
1466
1467/*
1468 * this function will check the on disk data for checksum errors, header
1469 * errors and read I/O errors. If any I/O errors happen, the exact pages
1470 * which are errored are marked as being bad. The goal is to enable scrub
1471 * to take those pages that are not errored from all the mirrors so that
1472 * the pages that are errored in the just handled mirror can be repaired.
1473 */
1474static void scrub_recheck_block(struct btrfs_fs_info *fs_info,
1475				struct scrub_block *sblock,
1476				int retry_failed_mirror)
 
1477{
1478	int page_num;
1479
1480	sblock->no_io_error_seen = 1;
 
 
1481
1482	for (page_num = 0; page_num < sblock->page_count; page_num++) {
1483		struct bio *bio;
1484		struct scrub_page *page = sblock->pagev[page_num];
 
 
1485
1486		if (page->dev->bdev == NULL) {
1487			page->io_error = 1;
1488			sblock->no_io_error_seen = 0;
1489			continue;
1490		}
1491
1492		WARN_ON(!page->page);
1493		bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
1494		if (!bio) {
1495			page->io_error = 1;
1496			sblock->no_io_error_seen = 0;
1497			continue;
1498		}
1499		bio->bi_bdev = page->dev->bdev;
 
 
 
1500
1501		bio_add_page(bio, page->page, PAGE_SIZE, 0);
1502		if (!retry_failed_mirror && scrub_is_page_on_raid56(page)) {
1503			if (scrub_submit_raid56_bio_wait(fs_info, bio, page))
1504				sblock->no_io_error_seen = 0;
1505		} else {
1506			bio->bi_iter.bi_sector = page->physical >> 9;
1507
1508			if (btrfsic_submit_bio_wait(READ, bio))
1509				sblock->no_io_error_seen = 0;
1510		}
 
 
 
 
1511
 
 
 
1512		bio_put(bio);
1513	}
1514
1515	if (sblock->no_io_error_seen)
1516		scrub_recheck_block_checksum(sblock);
 
 
 
 
1517}
1518
1519static inline int scrub_check_fsid(u8 fsid[],
1520				   struct scrub_page *spage)
 
 
 
1521{
1522	struct btrfs_fs_devices *fs_devices = spage->dev->fs_devices;
1523	int ret;
 
 
 
1524
1525	ret = memcmp(fsid, fs_devices->fsid, BTRFS_UUID_SIZE);
1526	return !ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1527}
1528
1529static void scrub_recheck_block_checksum(struct scrub_block *sblock)
1530{
1531	sblock->header_error = 0;
1532	sblock->checksum_error = 0;
1533	sblock->generation_error = 0;
1534
1535	if (sblock->pagev[0]->flags & BTRFS_EXTENT_FLAG_DATA)
1536		scrub_checksum_data(sblock);
1537	else
1538		scrub_checksum_tree_block(sblock);
1539}
1540
1541static int scrub_repair_block_from_good_copy(struct scrub_block *sblock_bad,
1542					     struct scrub_block *sblock_good)
 
1543{
1544	int page_num;
1545	int ret = 0;
1546
1547	for (page_num = 0; page_num < sblock_bad->page_count; page_num++) {
1548		int ret_sub;
1549
1550		ret_sub = scrub_repair_page_from_good_copy(sblock_bad,
1551							   sblock_good,
1552							   page_num, 1);
 
1553		if (ret_sub)
1554			ret = ret_sub;
1555	}
1556
1557	return ret;
1558}
1559
1560static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
1561					    struct scrub_block *sblock_good,
1562					    int page_num, int force_write)
1563{
1564	struct scrub_page *page_bad = sblock_bad->pagev[page_num];
1565	struct scrub_page *page_good = sblock_good->pagev[page_num];
1566
1567	BUG_ON(page_bad->page == NULL);
1568	BUG_ON(page_good->page == NULL);
1569	if (force_write || sblock_bad->header_error ||
1570	    sblock_bad->checksum_error || page_bad->io_error) {
1571		struct bio *bio;
1572		int ret;
 
1573
1574		if (!page_bad->dev->bdev) {
1575			btrfs_warn_rl(sblock_bad->sctx->dev_root->fs_info,
1576				"scrub_repair_page_from_good_copy(bdev == NULL) "
1577				"is unexpected");
1578			return -EIO;
1579		}
1580
1581		bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
1582		if (!bio)
1583			return -EIO;
1584		bio->bi_bdev = page_bad->dev->bdev;
1585		bio->bi_iter.bi_sector = page_bad->physical >> 9;
 
 
1586
1587		ret = bio_add_page(bio, page_good->page, PAGE_SIZE, 0);
1588		if (PAGE_SIZE != ret) {
1589			bio_put(bio);
1590			return -EIO;
1591		}
 
1592
1593		if (btrfsic_submit_bio_wait(WRITE, bio)) {
 
 
1594			btrfs_dev_stat_inc_and_print(page_bad->dev,
1595				BTRFS_DEV_STAT_WRITE_ERRS);
1596			btrfs_dev_replace_stats_inc(
1597				&sblock_bad->sctx->dev_root->fs_info->
1598				dev_replace.num_write_errors);
1599			bio_put(bio);
1600			return -EIO;
1601		}
1602		bio_put(bio);
1603	}
1604
1605	return 0;
1606}
1607
1608static void scrub_write_block_to_dev_replace(struct scrub_block *sblock)
1609{
1610	int page_num;
1611
1612	/*
1613	 * This block is used for the check of the parity on the source device,
1614	 * so the data needn't be written into the destination device.
1615	 */
1616	if (sblock->sparity)
1617		return;
1618
1619	for (page_num = 0; page_num < sblock->page_count; page_num++) {
1620		int ret;
1621
1622		ret = scrub_write_page_to_dev_replace(sblock, page_num);
1623		if (ret)
1624			btrfs_dev_replace_stats_inc(
1625				&sblock->sctx->dev_root->fs_info->dev_replace.
1626				num_write_errors);
1627	}
1628}
1629
1630static int scrub_write_page_to_dev_replace(struct scrub_block *sblock,
1631					   int page_num)
1632{
1633	struct scrub_page *spage = sblock->pagev[page_num];
1634
1635	BUG_ON(spage->page == NULL);
1636	if (spage->io_error) {
1637		void *mapped_buffer = kmap_atomic(spage->page);
1638
1639		memset(mapped_buffer, 0, PAGE_SIZE);
1640		flush_dcache_page(spage->page);
1641		kunmap_atomic(mapped_buffer);
1642	}
1643	return scrub_add_page_to_wr_bio(sblock->sctx, spage);
1644}
1645
1646static int scrub_add_page_to_wr_bio(struct scrub_ctx *sctx,
1647				    struct scrub_page *spage)
1648{
1649	struct scrub_wr_ctx *wr_ctx = &sctx->wr_ctx;
1650	struct scrub_bio *sbio;
1651	int ret;
1652
1653	mutex_lock(&wr_ctx->wr_lock);
1654again:
1655	if (!wr_ctx->wr_curr_bio) {
1656		wr_ctx->wr_curr_bio = kzalloc(sizeof(*wr_ctx->wr_curr_bio),
1657					      GFP_KERNEL);
1658		if (!wr_ctx->wr_curr_bio) {
1659			mutex_unlock(&wr_ctx->wr_lock);
1660			return -ENOMEM;
1661		}
1662		wr_ctx->wr_curr_bio->sctx = sctx;
1663		wr_ctx->wr_curr_bio->page_count = 0;
1664	}
1665	sbio = wr_ctx->wr_curr_bio;
1666	if (sbio->page_count == 0) {
1667		struct bio *bio;
1668
1669		sbio->physical = spage->physical_for_dev_replace;
1670		sbio->logical = spage->logical;
1671		sbio->dev = wr_ctx->tgtdev;
1672		bio = sbio->bio;
1673		if (!bio) {
1674			bio = btrfs_io_bio_alloc(GFP_KERNEL,
1675					wr_ctx->pages_per_wr_bio);
1676			if (!bio) {
1677				mutex_unlock(&wr_ctx->wr_lock);
1678				return -ENOMEM;
1679			}
1680			sbio->bio = bio;
1681		}
1682
1683		bio->bi_private = sbio;
1684		bio->bi_end_io = scrub_wr_bio_end_io;
1685		bio->bi_bdev = sbio->dev->bdev;
1686		bio->bi_iter.bi_sector = sbio->physical >> 9;
1687		sbio->err = 0;
1688	} else if (sbio->physical + sbio->page_count * PAGE_SIZE !=
1689		   spage->physical_for_dev_replace ||
1690		   sbio->logical + sbio->page_count * PAGE_SIZE !=
1691		   spage->logical) {
1692		scrub_wr_submit(sctx);
1693		goto again;
1694	}
1695
1696	ret = bio_add_page(sbio->bio, spage->page, PAGE_SIZE, 0);
1697	if (ret != PAGE_SIZE) {
1698		if (sbio->page_count < 1) {
1699			bio_put(sbio->bio);
1700			sbio->bio = NULL;
1701			mutex_unlock(&wr_ctx->wr_lock);
1702			return -EIO;
1703		}
1704		scrub_wr_submit(sctx);
1705		goto again;
1706	}
1707
1708	sbio->pagev[sbio->page_count] = spage;
1709	scrub_page_get(spage);
1710	sbio->page_count++;
1711	if (sbio->page_count == wr_ctx->pages_per_wr_bio)
1712		scrub_wr_submit(sctx);
1713	mutex_unlock(&wr_ctx->wr_lock);
1714
1715	return 0;
1716}
1717
1718static void scrub_wr_submit(struct scrub_ctx *sctx)
1719{
1720	struct scrub_wr_ctx *wr_ctx = &sctx->wr_ctx;
1721	struct scrub_bio *sbio;
1722
1723	if (!wr_ctx->wr_curr_bio)
1724		return;
1725
1726	sbio = wr_ctx->wr_curr_bio;
1727	wr_ctx->wr_curr_bio = NULL;
1728	WARN_ON(!sbio->bio->bi_bdev);
1729	scrub_pending_bio_inc(sctx);
1730	/* process all writes in a single worker thread. Then the block layer
1731	 * orders the requests before sending them to the driver which
1732	 * doubled the write performance on spinning disks when measured
1733	 * with Linux 3.5 */
1734	btrfsic_submit_bio(WRITE, sbio->bio);
1735}
1736
1737static void scrub_wr_bio_end_io(struct bio *bio)
1738{
1739	struct scrub_bio *sbio = bio->bi_private;
1740	struct btrfs_fs_info *fs_info = sbio->dev->dev_root->fs_info;
1741
1742	sbio->err = bio->bi_error;
1743	sbio->bio = bio;
1744
1745	btrfs_init_work(&sbio->work, btrfs_scrubwrc_helper,
1746			 scrub_wr_bio_end_io_worker, NULL, NULL);
1747	btrfs_queue_work(fs_info->scrub_wr_completion_workers, &sbio->work);
1748}
1749
1750static void scrub_wr_bio_end_io_worker(struct btrfs_work *work)
1751{
1752	struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
1753	struct scrub_ctx *sctx = sbio->sctx;
1754	int i;
1755
1756	WARN_ON(sbio->page_count > SCRUB_PAGES_PER_WR_BIO);
1757	if (sbio->err) {
1758		struct btrfs_dev_replace *dev_replace =
1759			&sbio->sctx->dev_root->fs_info->dev_replace;
1760
1761		for (i = 0; i < sbio->page_count; i++) {
1762			struct scrub_page *spage = sbio->pagev[i];
1763
1764			spage->io_error = 1;
1765			btrfs_dev_replace_stats_inc(&dev_replace->
1766						    num_write_errors);
1767		}
1768	}
1769
1770	for (i = 0; i < sbio->page_count; i++)
1771		scrub_page_put(sbio->pagev[i]);
1772
1773	bio_put(sbio->bio);
1774	kfree(sbio);
1775	scrub_pending_bio_dec(sctx);
1776}
1777
1778static int scrub_checksum(struct scrub_block *sblock)
1779{
1780	u64 flags;
1781	int ret;
1782
1783	/*
1784	 * No need to initialize these stats currently,
1785	 * because this function only use return value
1786	 * instead of these stats value.
1787	 *
1788	 * Todo:
1789	 * always use stats
1790	 */
1791	sblock->header_error = 0;
1792	sblock->generation_error = 0;
1793	sblock->checksum_error = 0;
1794
1795	WARN_ON(sblock->page_count < 1);
1796	flags = sblock->pagev[0]->flags;
1797	ret = 0;
1798	if (flags & BTRFS_EXTENT_FLAG_DATA)
1799		ret = scrub_checksum_data(sblock);
1800	else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
1801		ret = scrub_checksum_tree_block(sblock);
1802	else if (flags & BTRFS_EXTENT_FLAG_SUPER)
1803		(void)scrub_checksum_super(sblock);
1804	else
1805		WARN_ON(1);
1806	if (ret)
1807		scrub_handle_errored_block(sblock);
1808
1809	return ret;
1810}
1811
1812static int scrub_checksum_data(struct scrub_block *sblock)
1813{
1814	struct scrub_ctx *sctx = sblock->sctx;
1815	u8 csum[BTRFS_CSUM_SIZE];
1816	u8 *on_disk_csum;
1817	struct page *page;
1818	void *buffer;
1819	u32 crc = ~(u32)0;
 
 
1820	u64 len;
1821	int index;
1822
1823	BUG_ON(sblock->page_count < 1);
1824	if (!sblock->pagev[0]->have_csum)
1825		return 0;
1826
1827	on_disk_csum = sblock->pagev[0]->csum;
1828	page = sblock->pagev[0]->page;
1829	buffer = kmap_atomic(page);
1830
1831	len = sctx->sectorsize;
1832	index = 0;
1833	for (;;) {
1834		u64 l = min_t(u64, len, PAGE_SIZE);
1835
1836		crc = btrfs_csum_data(buffer, crc, l);
1837		kunmap_atomic(buffer);
1838		len -= l;
1839		if (len == 0)
1840			break;
1841		index++;
1842		BUG_ON(index >= sblock->page_count);
1843		BUG_ON(!sblock->pagev[index]->page);
1844		page = sblock->pagev[index]->page;
1845		buffer = kmap_atomic(page);
1846	}
1847
1848	btrfs_csum_final(crc, csum);
1849	if (memcmp(csum, on_disk_csum, sctx->csum_size))
1850		sblock->checksum_error = 1;
1851
1852	return sblock->checksum_error;
1853}
1854
1855static int scrub_checksum_tree_block(struct scrub_block *sblock)
1856{
1857	struct scrub_ctx *sctx = sblock->sctx;
1858	struct btrfs_header *h;
1859	struct btrfs_root *root = sctx->dev_root;
1860	struct btrfs_fs_info *fs_info = root->fs_info;
1861	u8 calculated_csum[BTRFS_CSUM_SIZE];
1862	u8 on_disk_csum[BTRFS_CSUM_SIZE];
1863	struct page *page;
1864	void *mapped_buffer;
1865	u64 mapped_size;
1866	void *p;
1867	u32 crc = ~(u32)0;
 
 
1868	u64 len;
1869	int index;
1870
1871	BUG_ON(sblock->page_count < 1);
1872	page = sblock->pagev[0]->page;
1873	mapped_buffer = kmap_atomic(page);
1874	h = (struct btrfs_header *)mapped_buffer;
1875	memcpy(on_disk_csum, h->csum, sctx->csum_size);
1876
1877	/*
1878	 * we don't use the getter functions here, as we
1879	 * a) don't have an extent buffer and
1880	 * b) the page is already kmapped
1881	 */
1882	if (sblock->pagev[0]->logical != btrfs_stack_header_bytenr(h))
1883		sblock->header_error = 1;
1884
1885	if (sblock->pagev[0]->generation != btrfs_stack_header_generation(h)) {
1886		sblock->header_error = 1;
1887		sblock->generation_error = 1;
1888	}
 
1889
1890	if (!scrub_check_fsid(h->fsid, sblock->pagev[0]))
1891		sblock->header_error = 1;
1892
1893	if (memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
1894		   BTRFS_UUID_SIZE))
1895		sblock->header_error = 1;
1896
1897	len = sctx->nodesize - BTRFS_CSUM_SIZE;
 
1898	mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE;
1899	p = ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE;
1900	index = 0;
1901	for (;;) {
1902		u64 l = min_t(u64, len, mapped_size);
1903
1904		crc = btrfs_csum_data(p, crc, l);
1905		kunmap_atomic(mapped_buffer);
1906		len -= l;
1907		if (len == 0)
1908			break;
1909		index++;
1910		BUG_ON(index >= sblock->page_count);
1911		BUG_ON(!sblock->pagev[index]->page);
1912		page = sblock->pagev[index]->page;
1913		mapped_buffer = kmap_atomic(page);
1914		mapped_size = PAGE_SIZE;
1915		p = mapped_buffer;
1916	}
1917
1918	btrfs_csum_final(crc, calculated_csum);
1919	if (memcmp(calculated_csum, on_disk_csum, sctx->csum_size))
1920		sblock->checksum_error = 1;
1921
1922	return sblock->header_error || sblock->checksum_error;
1923}
1924
1925static int scrub_checksum_super(struct scrub_block *sblock)
1926{
1927	struct btrfs_super_block *s;
1928	struct scrub_ctx *sctx = sblock->sctx;
 
 
1929	u8 calculated_csum[BTRFS_CSUM_SIZE];
1930	u8 on_disk_csum[BTRFS_CSUM_SIZE];
1931	struct page *page;
1932	void *mapped_buffer;
1933	u64 mapped_size;
1934	void *p;
1935	u32 crc = ~(u32)0;
1936	int fail_gen = 0;
1937	int fail_cor = 0;
1938	u64 len;
1939	int index;
1940
1941	BUG_ON(sblock->page_count < 1);
1942	page = sblock->pagev[0]->page;
1943	mapped_buffer = kmap_atomic(page);
1944	s = (struct btrfs_super_block *)mapped_buffer;
1945	memcpy(on_disk_csum, s->csum, sctx->csum_size);
1946
1947	if (sblock->pagev[0]->logical != btrfs_super_bytenr(s))
1948		++fail_cor;
1949
1950	if (sblock->pagev[0]->generation != btrfs_super_generation(s))
1951		++fail_gen;
1952
1953	if (!scrub_check_fsid(s->fsid, sblock->pagev[0]))
1954		++fail_cor;
1955
1956	len = BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE;
1957	mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE;
1958	p = ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE;
1959	index = 0;
1960	for (;;) {
1961		u64 l = min_t(u64, len, mapped_size);
1962
1963		crc = btrfs_csum_data(p, crc, l);
1964		kunmap_atomic(mapped_buffer);
1965		len -= l;
1966		if (len == 0)
1967			break;
1968		index++;
1969		BUG_ON(index >= sblock->page_count);
1970		BUG_ON(!sblock->pagev[index]->page);
1971		page = sblock->pagev[index]->page;
1972		mapped_buffer = kmap_atomic(page);
1973		mapped_size = PAGE_SIZE;
1974		p = mapped_buffer;
1975	}
1976
1977	btrfs_csum_final(crc, calculated_csum);
1978	if (memcmp(calculated_csum, on_disk_csum, sctx->csum_size))
1979		++fail_cor;
1980
1981	if (fail_cor + fail_gen) {
1982		/*
1983		 * if we find an error in a super block, we just report it.
1984		 * They will get written with the next transaction commit
1985		 * anyway
1986		 */
1987		spin_lock(&sctx->stat_lock);
1988		++sctx->stat.super_errors;
1989		spin_unlock(&sctx->stat_lock);
1990		if (fail_cor)
1991			btrfs_dev_stat_inc_and_print(sblock->pagev[0]->dev,
1992				BTRFS_DEV_STAT_CORRUPTION_ERRS);
1993		else
1994			btrfs_dev_stat_inc_and_print(sblock->pagev[0]->dev,
1995				BTRFS_DEV_STAT_GENERATION_ERRS);
1996	}
1997
1998	return fail_cor + fail_gen;
1999}
2000
2001static void scrub_block_get(struct scrub_block *sblock)
2002{
2003	atomic_inc(&sblock->refs);
2004}
2005
2006static void scrub_block_put(struct scrub_block *sblock)
2007{
2008	if (atomic_dec_and_test(&sblock->refs)) {
2009		int i;
2010
2011		if (sblock->sparity)
2012			scrub_parity_put(sblock->sparity);
2013
2014		for (i = 0; i < sblock->page_count; i++)
2015			scrub_page_put(sblock->pagev[i]);
 
2016		kfree(sblock);
2017	}
2018}
2019
2020static void scrub_page_get(struct scrub_page *spage)
2021{
2022	atomic_inc(&spage->refs);
2023}
2024
2025static void scrub_page_put(struct scrub_page *spage)
2026{
2027	if (atomic_dec_and_test(&spage->refs)) {
2028		if (spage->page)
2029			__free_page(spage->page);
2030		kfree(spage);
2031	}
2032}
2033
2034static void scrub_submit(struct scrub_ctx *sctx)
2035{
2036	struct scrub_bio *sbio;
2037
2038	if (sctx->curr == -1)
2039		return;
2040
2041	sbio = sctx->bios[sctx->curr];
2042	sctx->curr = -1;
2043	scrub_pending_bio_inc(sctx);
 
2044	btrfsic_submit_bio(READ, sbio->bio);
2045}
2046
2047static int scrub_add_page_to_rd_bio(struct scrub_ctx *sctx,
2048				    struct scrub_page *spage)
2049{
2050	struct scrub_block *sblock = spage->sblock;
2051	struct scrub_bio *sbio;
2052	int ret;
2053
2054again:
2055	/*
2056	 * grab a fresh bio or wait for one to become available
2057	 */
2058	while (sctx->curr == -1) {
2059		spin_lock(&sctx->list_lock);
2060		sctx->curr = sctx->first_free;
2061		if (sctx->curr != -1) {
2062			sctx->first_free = sctx->bios[sctx->curr]->next_free;
2063			sctx->bios[sctx->curr]->next_free = -1;
2064			sctx->bios[sctx->curr]->page_count = 0;
2065			spin_unlock(&sctx->list_lock);
2066		} else {
2067			spin_unlock(&sctx->list_lock);
2068			wait_event(sctx->list_wait, sctx->first_free != -1);
2069		}
2070	}
2071	sbio = sctx->bios[sctx->curr];
2072	if (sbio->page_count == 0) {
2073		struct bio *bio;
2074
2075		sbio->physical = spage->physical;
2076		sbio->logical = spage->logical;
2077		sbio->dev = spage->dev;
2078		bio = sbio->bio;
2079		if (!bio) {
2080			bio = btrfs_io_bio_alloc(GFP_KERNEL,
2081					sctx->pages_per_rd_bio);
2082			if (!bio)
2083				return -ENOMEM;
2084			sbio->bio = bio;
2085		}
2086
2087		bio->bi_private = sbio;
2088		bio->bi_end_io = scrub_bio_end_io;
2089		bio->bi_bdev = sbio->dev->bdev;
2090		bio->bi_iter.bi_sector = sbio->physical >> 9;
2091		sbio->err = 0;
2092	} else if (sbio->physical + sbio->page_count * PAGE_SIZE !=
2093		   spage->physical ||
2094		   sbio->logical + sbio->page_count * PAGE_SIZE !=
2095		   spage->logical ||
2096		   sbio->dev != spage->dev) {
2097		scrub_submit(sctx);
2098		goto again;
2099	}
2100
2101	sbio->pagev[sbio->page_count] = spage;
2102	ret = bio_add_page(sbio->bio, spage->page, PAGE_SIZE, 0);
2103	if (ret != PAGE_SIZE) {
2104		if (sbio->page_count < 1) {
2105			bio_put(sbio->bio);
2106			sbio->bio = NULL;
2107			return -EIO;
2108		}
2109		scrub_submit(sctx);
2110		goto again;
2111	}
2112
2113	scrub_block_get(sblock); /* one for the page added to the bio */
2114	atomic_inc(&sblock->outstanding_pages);
2115	sbio->page_count++;
2116	if (sbio->page_count == sctx->pages_per_rd_bio)
2117		scrub_submit(sctx);
2118
2119	return 0;
2120}
2121
2122static void scrub_missing_raid56_end_io(struct bio *bio)
2123{
2124	struct scrub_block *sblock = bio->bi_private;
2125	struct btrfs_fs_info *fs_info = sblock->sctx->dev_root->fs_info;
2126
2127	if (bio->bi_error)
2128		sblock->no_io_error_seen = 0;
2129
2130	btrfs_queue_work(fs_info->scrub_workers, &sblock->work);
2131}
2132
2133static void scrub_missing_raid56_worker(struct btrfs_work *work)
2134{
2135	struct scrub_block *sblock = container_of(work, struct scrub_block, work);
2136	struct scrub_ctx *sctx = sblock->sctx;
2137	u64 logical;
2138	struct btrfs_device *dev;
2139
2140	logical = sblock->pagev[0]->logical;
2141	dev = sblock->pagev[0]->dev;
2142
2143	if (sblock->no_io_error_seen)
2144		scrub_recheck_block_checksum(sblock);
2145
2146	if (!sblock->no_io_error_seen) {
2147		spin_lock(&sctx->stat_lock);
2148		sctx->stat.read_errors++;
2149		spin_unlock(&sctx->stat_lock);
2150		btrfs_err_rl_in_rcu(sctx->dev_root->fs_info,
2151			"IO error rebuilding logical %llu for dev %s",
2152			logical, rcu_str_deref(dev->name));
2153	} else if (sblock->header_error || sblock->checksum_error) {
2154		spin_lock(&sctx->stat_lock);
2155		sctx->stat.uncorrectable_errors++;
2156		spin_unlock(&sctx->stat_lock);
2157		btrfs_err_rl_in_rcu(sctx->dev_root->fs_info,
2158			"failed to rebuild valid logical %llu for dev %s",
2159			logical, rcu_str_deref(dev->name));
2160	} else {
2161		scrub_write_block_to_dev_replace(sblock);
2162	}
2163
2164	scrub_block_put(sblock);
2165
2166	if (sctx->is_dev_replace &&
2167	    atomic_read(&sctx->wr_ctx.flush_all_writes)) {
2168		mutex_lock(&sctx->wr_ctx.wr_lock);
2169		scrub_wr_submit(sctx);
2170		mutex_unlock(&sctx->wr_ctx.wr_lock);
2171	}
2172
2173	scrub_pending_bio_dec(sctx);
2174}
2175
2176static void scrub_missing_raid56_pages(struct scrub_block *sblock)
2177{
2178	struct scrub_ctx *sctx = sblock->sctx;
2179	struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;
2180	u64 length = sblock->page_count * PAGE_SIZE;
2181	u64 logical = sblock->pagev[0]->logical;
2182	struct btrfs_bio *bbio;
2183	struct bio *bio;
2184	struct btrfs_raid_bio *rbio;
2185	int ret;
2186	int i;
2187
2188	ret = btrfs_map_sblock(fs_info, REQ_GET_READ_MIRRORS, logical, &length,
2189			       &bbio, 0, 1);
2190	if (ret || !bbio || !bbio->raid_map)
2191		goto bbio_out;
2192
2193	if (WARN_ON(!sctx->is_dev_replace ||
2194		    !(bbio->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK))) {
2195		/*
2196		 * We shouldn't be scrubbing a missing device. Even for dev
2197		 * replace, we should only get here for RAID 5/6. We either
2198		 * managed to mount something with no mirrors remaining or
2199		 * there's a bug in scrub_remap_extent()/btrfs_map_block().
2200		 */
2201		goto bbio_out;
2202	}
2203
2204	bio = btrfs_io_bio_alloc(GFP_NOFS, 0);
2205	if (!bio)
2206		goto bbio_out;
2207
2208	bio->bi_iter.bi_sector = logical >> 9;
2209	bio->bi_private = sblock;
2210	bio->bi_end_io = scrub_missing_raid56_end_io;
2211
2212	rbio = raid56_alloc_missing_rbio(sctx->dev_root, bio, bbio, length);
2213	if (!rbio)
2214		goto rbio_out;
2215
2216	for (i = 0; i < sblock->page_count; i++) {
2217		struct scrub_page *spage = sblock->pagev[i];
2218
2219		raid56_add_scrub_pages(rbio, spage->page, spage->logical);
2220	}
2221
2222	btrfs_init_work(&sblock->work, btrfs_scrub_helper,
2223			scrub_missing_raid56_worker, NULL, NULL);
2224	scrub_block_get(sblock);
2225	scrub_pending_bio_inc(sctx);
2226	raid56_submit_missing_rbio(rbio);
2227	return;
2228
2229rbio_out:
2230	bio_put(bio);
2231bbio_out:
2232	btrfs_put_bbio(bbio);
2233	spin_lock(&sctx->stat_lock);
2234	sctx->stat.malloc_errors++;
2235	spin_unlock(&sctx->stat_lock);
2236}
2237
2238static int scrub_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
2239		       u64 physical, struct btrfs_device *dev, u64 flags,
2240		       u64 gen, int mirror_num, u8 *csum, int force,
2241		       u64 physical_for_dev_replace)
2242{
2243	struct scrub_block *sblock;
2244	int index;
2245
2246	sblock = kzalloc(sizeof(*sblock), GFP_KERNEL);
2247	if (!sblock) {
2248		spin_lock(&sctx->stat_lock);
2249		sctx->stat.malloc_errors++;
2250		spin_unlock(&sctx->stat_lock);
2251		return -ENOMEM;
2252	}
2253
2254	/* one ref inside this function, plus one for each page added to
2255	 * a bio later on */
2256	atomic_set(&sblock->refs, 1);
2257	sblock->sctx = sctx;
2258	sblock->no_io_error_seen = 1;
2259
2260	for (index = 0; len > 0; index++) {
2261		struct scrub_page *spage;
2262		u64 l = min_t(u64, len, PAGE_SIZE);
2263
2264		spage = kzalloc(sizeof(*spage), GFP_KERNEL);
2265		if (!spage) {
2266leave_nomem:
2267			spin_lock(&sctx->stat_lock);
2268			sctx->stat.malloc_errors++;
2269			spin_unlock(&sctx->stat_lock);
2270			scrub_block_put(sblock);
 
 
 
 
2271			return -ENOMEM;
2272		}
2273		BUG_ON(index >= SCRUB_MAX_PAGES_PER_BLOCK);
2274		scrub_page_get(spage);
2275		sblock->pagev[index] = spage;
2276		spage->sblock = sblock;
2277		spage->dev = dev;
2278		spage->flags = flags;
2279		spage->generation = gen;
2280		spage->logical = logical;
2281		spage->physical = physical;
2282		spage->physical_for_dev_replace = physical_for_dev_replace;
2283		spage->mirror_num = mirror_num;
2284		if (csum) {
2285			spage->have_csum = 1;
2286			memcpy(spage->csum, csum, sctx->csum_size);
2287		} else {
2288			spage->have_csum = 0;
2289		}
2290		sblock->page_count++;
2291		spage->page = alloc_page(GFP_KERNEL);
2292		if (!spage->page)
2293			goto leave_nomem;
2294		len -= l;
2295		logical += l;
2296		physical += l;
2297		physical_for_dev_replace += l;
2298	}
2299
2300	WARN_ON(sblock->page_count == 0);
2301	if (dev->missing) {
2302		/*
2303		 * This case should only be hit for RAID 5/6 device replace. See
2304		 * the comment in scrub_missing_raid56_pages() for details.
2305		 */
2306		scrub_missing_raid56_pages(sblock);
2307	} else {
2308		for (index = 0; index < sblock->page_count; index++) {
2309			struct scrub_page *spage = sblock->pagev[index];
2310			int ret;
2311
2312			ret = scrub_add_page_to_rd_bio(sctx, spage);
2313			if (ret) {
2314				scrub_block_put(sblock);
2315				return ret;
2316			}
2317		}
2318
2319		if (force)
2320			scrub_submit(sctx);
 
 
 
2321	}
2322
 
 
 
2323	/* last one frees, either here or in bio completion for last page */
2324	scrub_block_put(sblock);
2325	return 0;
2326}
2327
2328static void scrub_bio_end_io(struct bio *bio)
2329{
2330	struct scrub_bio *sbio = bio->bi_private;
2331	struct btrfs_fs_info *fs_info = sbio->dev->dev_root->fs_info;
 
2332
2333	sbio->err = bio->bi_error;
2334	sbio->bio = bio;
2335
2336	btrfs_queue_work(fs_info->scrub_workers, &sbio->work);
2337}
2338
2339static void scrub_bio_end_io_worker(struct btrfs_work *work)
2340{
2341	struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
2342	struct scrub_ctx *sctx = sbio->sctx;
2343	int i;
2344
2345	BUG_ON(sbio->page_count > SCRUB_PAGES_PER_RD_BIO);
2346	if (sbio->err) {
2347		for (i = 0; i < sbio->page_count; i++) {
2348			struct scrub_page *spage = sbio->pagev[i];
2349
2350			spage->io_error = 1;
2351			spage->sblock->no_io_error_seen = 0;
2352		}
2353	}
2354
2355	/* now complete the scrub_block items that have all pages completed */
2356	for (i = 0; i < sbio->page_count; i++) {
2357		struct scrub_page *spage = sbio->pagev[i];
2358		struct scrub_block *sblock = spage->sblock;
2359
2360		if (atomic_dec_and_test(&sblock->outstanding_pages))
2361			scrub_block_complete(sblock);
2362		scrub_block_put(sblock);
2363	}
2364
2365	bio_put(sbio->bio);
2366	sbio->bio = NULL;
2367	spin_lock(&sctx->list_lock);
2368	sbio->next_free = sctx->first_free;
2369	sctx->first_free = sbio->index;
2370	spin_unlock(&sctx->list_lock);
2371
2372	if (sctx->is_dev_replace &&
2373	    atomic_read(&sctx->wr_ctx.flush_all_writes)) {
2374		mutex_lock(&sctx->wr_ctx.wr_lock);
2375		scrub_wr_submit(sctx);
2376		mutex_unlock(&sctx->wr_ctx.wr_lock);
2377	}
2378
2379	scrub_pending_bio_dec(sctx);
2380}
2381
2382static inline void __scrub_mark_bitmap(struct scrub_parity *sparity,
2383				       unsigned long *bitmap,
2384				       u64 start, u64 len)
2385{
2386	u32 offset;
2387	int nsectors;
2388	int sectorsize = sparity->sctx->dev_root->sectorsize;
2389
2390	if (len >= sparity->stripe_len) {
2391		bitmap_set(bitmap, 0, sparity->nsectors);
2392		return;
2393	}
2394
2395	start -= sparity->logic_start;
2396	start = div_u64_rem(start, sparity->stripe_len, &offset);
2397	offset /= sectorsize;
2398	nsectors = (int)len / sectorsize;
2399
2400	if (offset + nsectors <= sparity->nsectors) {
2401		bitmap_set(bitmap, offset, nsectors);
2402		return;
 
 
 
2403	}
2404
2405	bitmap_set(bitmap, offset, sparity->nsectors - offset);
2406	bitmap_set(bitmap, 0, nsectors - (sparity->nsectors - offset));
2407}
2408
2409static inline void scrub_parity_mark_sectors_error(struct scrub_parity *sparity,
2410						   u64 start, u64 len)
2411{
2412	__scrub_mark_bitmap(sparity, sparity->ebitmap, start, len);
2413}
2414
2415static inline void scrub_parity_mark_sectors_data(struct scrub_parity *sparity,
2416						  u64 start, u64 len)
2417{
2418	__scrub_mark_bitmap(sparity, sparity->dbitmap, start, len);
2419}
2420
2421static void scrub_block_complete(struct scrub_block *sblock)
2422{
2423	int corrupted = 0;
2424
2425	if (!sblock->no_io_error_seen) {
2426		corrupted = 1;
2427		scrub_handle_errored_block(sblock);
2428	} else {
2429		/*
2430		 * if has checksum error, write via repair mechanism in
2431		 * dev replace case, otherwise write here in dev replace
2432		 * case.
2433		 */
2434		corrupted = scrub_checksum(sblock);
2435		if (!corrupted && sblock->sctx->is_dev_replace)
2436			scrub_write_block_to_dev_replace(sblock);
2437	}
2438
2439	if (sblock->sparity && corrupted && !sblock->data_corrected) {
2440		u64 start = sblock->pagev[0]->logical;
2441		u64 end = sblock->pagev[sblock->page_count - 1]->logical +
2442			  PAGE_SIZE;
2443
2444		scrub_parity_mark_sectors_error(sblock->sparity,
2445						start, end - start);
2446	}
2447}
2448
2449static int scrub_find_csum(struct scrub_ctx *sctx, u64 logical, u8 *csum)
 
2450{
2451	struct btrfs_ordered_sum *sum = NULL;
2452	unsigned long index;
 
2453	unsigned long num_sectors;
2454
2455	while (!list_empty(&sctx->csum_list)) {
2456		sum = list_first_entry(&sctx->csum_list,
2457				       struct btrfs_ordered_sum, list);
2458		if (sum->bytenr > logical)
2459			return 0;
2460		if (sum->bytenr + sum->len > logical)
2461			break;
2462
2463		++sctx->stat.csum_discards;
2464		list_del(&sum->list);
2465		kfree(sum);
2466		sum = NULL;
2467	}
2468	if (!sum)
2469		return 0;
2470
2471	index = ((u32)(logical - sum->bytenr)) / sctx->sectorsize;
2472	num_sectors = sum->len / sctx->sectorsize;
2473	memcpy(csum, sum->sums + index, sctx->csum_size);
2474	if (index == num_sectors - 1) {
 
 
 
 
 
2475		list_del(&sum->list);
2476		kfree(sum);
2477	}
2478	return 1;
2479}
2480
2481/* scrub extent tries to collect up to 64 kB for each bio */
2482static int scrub_extent(struct scrub_ctx *sctx, u64 logical, u64 len,
2483			u64 physical, struct btrfs_device *dev, u64 flags,
2484			u64 gen, int mirror_num, u64 physical_for_dev_replace)
2485{
2486	int ret;
2487	u8 csum[BTRFS_CSUM_SIZE];
2488	u32 blocksize;
2489
2490	if (flags & BTRFS_EXTENT_FLAG_DATA) {
2491		blocksize = sctx->sectorsize;
2492		spin_lock(&sctx->stat_lock);
2493		sctx->stat.data_extents_scrubbed++;
2494		sctx->stat.data_bytes_scrubbed += len;
2495		spin_unlock(&sctx->stat_lock);
2496	} else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
2497		blocksize = sctx->nodesize;
2498		spin_lock(&sctx->stat_lock);
2499		sctx->stat.tree_extents_scrubbed++;
2500		sctx->stat.tree_bytes_scrubbed += len;
2501		spin_unlock(&sctx->stat_lock);
 
2502	} else {
2503		blocksize = sctx->sectorsize;
2504		WARN_ON(1);
2505	}
2506
2507	while (len) {
2508		u64 l = min_t(u64, len, blocksize);
2509		int have_csum = 0;
2510
2511		if (flags & BTRFS_EXTENT_FLAG_DATA) {
2512			/* push csums to sbio */
2513			have_csum = scrub_find_csum(sctx, logical, csum);
2514			if (have_csum == 0)
2515				++sctx->stat.no_csum;
2516			if (sctx->is_dev_replace && !have_csum) {
2517				ret = copy_nocow_pages(sctx, logical, l,
2518						       mirror_num,
2519						      physical_for_dev_replace);
2520				goto behind_scrub_pages;
2521			}
2522		}
2523		ret = scrub_pages(sctx, logical, l, physical, dev, flags, gen,
2524				  mirror_num, have_csum ? csum : NULL, 0,
2525				  physical_for_dev_replace);
2526behind_scrub_pages:
2527		if (ret)
2528			return ret;
2529		len -= l;
2530		logical += l;
2531		physical += l;
2532		physical_for_dev_replace += l;
2533	}
2534	return 0;
2535}
2536
2537static int scrub_pages_for_parity(struct scrub_parity *sparity,
2538				  u64 logical, u64 len,
2539				  u64 physical, struct btrfs_device *dev,
2540				  u64 flags, u64 gen, int mirror_num, u8 *csum)
2541{
2542	struct scrub_ctx *sctx = sparity->sctx;
2543	struct scrub_block *sblock;
2544	int index;
2545
2546	sblock = kzalloc(sizeof(*sblock), GFP_KERNEL);
2547	if (!sblock) {
2548		spin_lock(&sctx->stat_lock);
2549		sctx->stat.malloc_errors++;
2550		spin_unlock(&sctx->stat_lock);
2551		return -ENOMEM;
2552	}
2553
2554	/* one ref inside this function, plus one for each page added to
2555	 * a bio later on */
2556	atomic_set(&sblock->refs, 1);
2557	sblock->sctx = sctx;
2558	sblock->no_io_error_seen = 1;
2559	sblock->sparity = sparity;
2560	scrub_parity_get(sparity);
2561
2562	for (index = 0; len > 0; index++) {
2563		struct scrub_page *spage;
2564		u64 l = min_t(u64, len, PAGE_SIZE);
2565
2566		spage = kzalloc(sizeof(*spage), GFP_KERNEL);
2567		if (!spage) {
2568leave_nomem:
2569			spin_lock(&sctx->stat_lock);
2570			sctx->stat.malloc_errors++;
2571			spin_unlock(&sctx->stat_lock);
2572			scrub_block_put(sblock);
2573			return -ENOMEM;
2574		}
2575		BUG_ON(index >= SCRUB_MAX_PAGES_PER_BLOCK);
2576		/* For scrub block */
2577		scrub_page_get(spage);
2578		sblock->pagev[index] = spage;
2579		/* For scrub parity */
2580		scrub_page_get(spage);
2581		list_add_tail(&spage->list, &sparity->spages);
2582		spage->sblock = sblock;
2583		spage->dev = dev;
2584		spage->flags = flags;
2585		spage->generation = gen;
2586		spage->logical = logical;
2587		spage->physical = physical;
2588		spage->mirror_num = mirror_num;
2589		if (csum) {
2590			spage->have_csum = 1;
2591			memcpy(spage->csum, csum, sctx->csum_size);
2592		} else {
2593			spage->have_csum = 0;
2594		}
2595		sblock->page_count++;
2596		spage->page = alloc_page(GFP_KERNEL);
2597		if (!spage->page)
2598			goto leave_nomem;
2599		len -= l;
2600		logical += l;
2601		physical += l;
2602	}
2603
2604	WARN_ON(sblock->page_count == 0);
2605	for (index = 0; index < sblock->page_count; index++) {
2606		struct scrub_page *spage = sblock->pagev[index];
2607		int ret;
2608
2609		ret = scrub_add_page_to_rd_bio(sctx, spage);
2610		if (ret) {
2611			scrub_block_put(sblock);
2612			return ret;
2613		}
2614	}
2615
2616	/* last one frees, either here or in bio completion for last page */
2617	scrub_block_put(sblock);
2618	return 0;
2619}
2620
2621static int scrub_extent_for_parity(struct scrub_parity *sparity,
2622				   u64 logical, u64 len,
2623				   u64 physical, struct btrfs_device *dev,
2624				   u64 flags, u64 gen, int mirror_num)
2625{
2626	struct scrub_ctx *sctx = sparity->sctx;
2627	int ret;
2628	u8 csum[BTRFS_CSUM_SIZE];
2629	u32 blocksize;
2630
2631	if (dev->missing) {
2632		scrub_parity_mark_sectors_error(sparity, logical, len);
2633		return 0;
2634	}
2635
2636	if (flags & BTRFS_EXTENT_FLAG_DATA) {
2637		blocksize = sctx->sectorsize;
2638	} else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
2639		blocksize = sctx->nodesize;
2640	} else {
2641		blocksize = sctx->sectorsize;
2642		WARN_ON(1);
2643	}
2644
2645	while (len) {
2646		u64 l = min_t(u64, len, blocksize);
2647		int have_csum = 0;
2648
2649		if (flags & BTRFS_EXTENT_FLAG_DATA) {
2650			/* push csums to sbio */
2651			have_csum = scrub_find_csum(sctx, logical, csum);
2652			if (have_csum == 0)
2653				goto skip;
2654		}
2655		ret = scrub_pages_for_parity(sparity, logical, l, physical, dev,
2656					     flags, gen, mirror_num,
2657					     have_csum ? csum : NULL);
2658		if (ret)
2659			return ret;
2660skip:
2661		len -= l;
2662		logical += l;
2663		physical += l;
2664	}
2665	return 0;
2666}
2667
2668/*
2669 * Given a physical address, this will calculate it's
2670 * logical offset. if this is a parity stripe, it will return
2671 * the most left data stripe's logical offset.
2672 *
2673 * return 0 if it is a data stripe, 1 means parity stripe.
2674 */
2675static int get_raid56_logic_offset(u64 physical, int num,
2676				   struct map_lookup *map, u64 *offset,
2677				   u64 *stripe_start)
2678{
2679	int i;
2680	int j = 0;
2681	u64 stripe_nr;
2682	u64 last_offset;
2683	u32 stripe_index;
2684	u32 rot;
2685
2686	last_offset = (physical - map->stripes[num].physical) *
2687		      nr_data_stripes(map);
2688	if (stripe_start)
2689		*stripe_start = last_offset;
2690
2691	*offset = last_offset;
2692	for (i = 0; i < nr_data_stripes(map); i++) {
2693		*offset = last_offset + i * map->stripe_len;
2694
2695		stripe_nr = div_u64(*offset, map->stripe_len);
2696		stripe_nr = div_u64(stripe_nr, nr_data_stripes(map));
2697
2698		/* Work out the disk rotation on this stripe-set */
2699		stripe_nr = div_u64_rem(stripe_nr, map->num_stripes, &rot);
2700		/* calculate which stripe this data locates */
2701		rot += i;
2702		stripe_index = rot % map->num_stripes;
2703		if (stripe_index == num)
2704			return 0;
2705		if (stripe_index < num)
2706			j++;
2707	}
2708	*offset = last_offset + j * map->stripe_len;
2709	return 1;
2710}
2711
2712static void scrub_free_parity(struct scrub_parity *sparity)
2713{
2714	struct scrub_ctx *sctx = sparity->sctx;
2715	struct scrub_page *curr, *next;
2716	int nbits;
2717
2718	nbits = bitmap_weight(sparity->ebitmap, sparity->nsectors);
2719	if (nbits) {
2720		spin_lock(&sctx->stat_lock);
2721		sctx->stat.read_errors += nbits;
2722		sctx->stat.uncorrectable_errors += nbits;
2723		spin_unlock(&sctx->stat_lock);
2724	}
2725
2726	list_for_each_entry_safe(curr, next, &sparity->spages, list) {
2727		list_del_init(&curr->list);
2728		scrub_page_put(curr);
2729	}
2730
2731	kfree(sparity);
2732}
2733
2734static void scrub_parity_bio_endio_worker(struct btrfs_work *work)
2735{
2736	struct scrub_parity *sparity = container_of(work, struct scrub_parity,
2737						    work);
2738	struct scrub_ctx *sctx = sparity->sctx;
2739
2740	scrub_free_parity(sparity);
2741	scrub_pending_bio_dec(sctx);
2742}
2743
2744static void scrub_parity_bio_endio(struct bio *bio)
2745{
2746	struct scrub_parity *sparity = (struct scrub_parity *)bio->bi_private;
2747
2748	if (bio->bi_error)
2749		bitmap_or(sparity->ebitmap, sparity->ebitmap, sparity->dbitmap,
2750			  sparity->nsectors);
2751
2752	bio_put(bio);
2753
2754	btrfs_init_work(&sparity->work, btrfs_scrubparity_helper,
2755			scrub_parity_bio_endio_worker, NULL, NULL);
2756	btrfs_queue_work(sparity->sctx->dev_root->fs_info->scrub_parity_workers,
2757			 &sparity->work);
2758}
2759
2760static void scrub_parity_check_and_repair(struct scrub_parity *sparity)
2761{
2762	struct scrub_ctx *sctx = sparity->sctx;
2763	struct bio *bio;
2764	struct btrfs_raid_bio *rbio;
2765	struct scrub_page *spage;
2766	struct btrfs_bio *bbio = NULL;
2767	u64 length;
2768	int ret;
2769
2770	if (!bitmap_andnot(sparity->dbitmap, sparity->dbitmap, sparity->ebitmap,
2771			   sparity->nsectors))
2772		goto out;
2773
2774	length = sparity->logic_end - sparity->logic_start;
2775	ret = btrfs_map_sblock(sctx->dev_root->fs_info, WRITE,
2776			       sparity->logic_start,
2777			       &length, &bbio, 0, 1);
2778	if (ret || !bbio || !bbio->raid_map)
2779		goto bbio_out;
2780
2781	bio = btrfs_io_bio_alloc(GFP_NOFS, 0);
2782	if (!bio)
2783		goto bbio_out;
2784
2785	bio->bi_iter.bi_sector = sparity->logic_start >> 9;
2786	bio->bi_private = sparity;
2787	bio->bi_end_io = scrub_parity_bio_endio;
2788
2789	rbio = raid56_parity_alloc_scrub_rbio(sctx->dev_root, bio, bbio,
2790					      length, sparity->scrub_dev,
2791					      sparity->dbitmap,
2792					      sparity->nsectors);
2793	if (!rbio)
2794		goto rbio_out;
2795
2796	list_for_each_entry(spage, &sparity->spages, list)
2797		raid56_add_scrub_pages(rbio, spage->page, spage->logical);
2798
2799	scrub_pending_bio_inc(sctx);
2800	raid56_parity_submit_scrub_rbio(rbio);
2801	return;
2802
2803rbio_out:
2804	bio_put(bio);
2805bbio_out:
2806	btrfs_put_bbio(bbio);
2807	bitmap_or(sparity->ebitmap, sparity->ebitmap, sparity->dbitmap,
2808		  sparity->nsectors);
2809	spin_lock(&sctx->stat_lock);
2810	sctx->stat.malloc_errors++;
2811	spin_unlock(&sctx->stat_lock);
2812out:
2813	scrub_free_parity(sparity);
2814}
2815
2816static inline int scrub_calc_parity_bitmap_len(int nsectors)
2817{
2818	return DIV_ROUND_UP(nsectors, BITS_PER_LONG) * sizeof(long);
2819}
2820
2821static void scrub_parity_get(struct scrub_parity *sparity)
2822{
2823	atomic_inc(&sparity->refs);
2824}
2825
2826static void scrub_parity_put(struct scrub_parity *sparity)
2827{
2828	if (!atomic_dec_and_test(&sparity->refs))
2829		return;
2830
2831	scrub_parity_check_and_repair(sparity);
2832}
2833
2834static noinline_for_stack int scrub_raid56_parity(struct scrub_ctx *sctx,
2835						  struct map_lookup *map,
2836						  struct btrfs_device *sdev,
2837						  struct btrfs_path *path,
2838						  u64 logic_start,
2839						  u64 logic_end)
2840{
2841	struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;
2842	struct btrfs_root *root = fs_info->extent_root;
2843	struct btrfs_root *csum_root = fs_info->csum_root;
2844	struct btrfs_extent_item *extent;
2845	struct btrfs_bio *bbio = NULL;
2846	u64 flags;
2847	int ret;
2848	int slot;
2849	struct extent_buffer *l;
2850	struct btrfs_key key;
2851	u64 generation;
2852	u64 extent_logical;
2853	u64 extent_physical;
2854	u64 extent_len;
2855	u64 mapped_length;
2856	struct btrfs_device *extent_dev;
2857	struct scrub_parity *sparity;
2858	int nsectors;
2859	int bitmap_len;
2860	int extent_mirror_num;
2861	int stop_loop = 0;
2862
2863	nsectors = map->stripe_len / root->sectorsize;
2864	bitmap_len = scrub_calc_parity_bitmap_len(nsectors);
2865	sparity = kzalloc(sizeof(struct scrub_parity) + 2 * bitmap_len,
2866			  GFP_NOFS);
2867	if (!sparity) {
2868		spin_lock(&sctx->stat_lock);
2869		sctx->stat.malloc_errors++;
2870		spin_unlock(&sctx->stat_lock);
2871		return -ENOMEM;
2872	}
2873
2874	sparity->stripe_len = map->stripe_len;
2875	sparity->nsectors = nsectors;
2876	sparity->sctx = sctx;
2877	sparity->scrub_dev = sdev;
2878	sparity->logic_start = logic_start;
2879	sparity->logic_end = logic_end;
2880	atomic_set(&sparity->refs, 1);
2881	INIT_LIST_HEAD(&sparity->spages);
2882	sparity->dbitmap = sparity->bitmap;
2883	sparity->ebitmap = (void *)sparity->bitmap + bitmap_len;
2884
2885	ret = 0;
2886	while (logic_start < logic_end) {
2887		if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
2888			key.type = BTRFS_METADATA_ITEM_KEY;
2889		else
2890			key.type = BTRFS_EXTENT_ITEM_KEY;
2891		key.objectid = logic_start;
2892		key.offset = (u64)-1;
2893
2894		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2895		if (ret < 0)
2896			goto out;
2897
2898		if (ret > 0) {
2899			ret = btrfs_previous_extent_item(root, path, 0);
2900			if (ret < 0)
2901				goto out;
2902			if (ret > 0) {
2903				btrfs_release_path(path);
2904				ret = btrfs_search_slot(NULL, root, &key,
2905							path, 0, 0);
2906				if (ret < 0)
2907					goto out;
2908			}
2909		}
2910
2911		stop_loop = 0;
2912		while (1) {
2913			u64 bytes;
2914
2915			l = path->nodes[0];
2916			slot = path->slots[0];
2917			if (slot >= btrfs_header_nritems(l)) {
2918				ret = btrfs_next_leaf(root, path);
2919				if (ret == 0)
2920					continue;
2921				if (ret < 0)
2922					goto out;
2923
2924				stop_loop = 1;
2925				break;
2926			}
2927			btrfs_item_key_to_cpu(l, &key, slot);
2928
2929			if (key.type != BTRFS_EXTENT_ITEM_KEY &&
2930			    key.type != BTRFS_METADATA_ITEM_KEY)
2931				goto next;
2932
2933			if (key.type == BTRFS_METADATA_ITEM_KEY)
2934				bytes = root->nodesize;
2935			else
2936				bytes = key.offset;
2937
2938			if (key.objectid + bytes <= logic_start)
2939				goto next;
2940
2941			if (key.objectid >= logic_end) {
2942				stop_loop = 1;
2943				break;
2944			}
2945
2946			while (key.objectid >= logic_start + map->stripe_len)
2947				logic_start += map->stripe_len;
2948
2949			extent = btrfs_item_ptr(l, slot,
2950						struct btrfs_extent_item);
2951			flags = btrfs_extent_flags(l, extent);
2952			generation = btrfs_extent_generation(l, extent);
2953
2954			if ((flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) &&
2955			    (key.objectid < logic_start ||
2956			     key.objectid + bytes >
2957			     logic_start + map->stripe_len)) {
2958				btrfs_err(fs_info, "scrub: tree block %llu spanning stripes, ignored. logical=%llu",
2959					  key.objectid, logic_start);
2960				spin_lock(&sctx->stat_lock);
2961				sctx->stat.uncorrectable_errors++;
2962				spin_unlock(&sctx->stat_lock);
2963				goto next;
2964			}
2965again:
2966			extent_logical = key.objectid;
2967			extent_len = bytes;
2968
2969			if (extent_logical < logic_start) {
2970				extent_len -= logic_start - extent_logical;
2971				extent_logical = logic_start;
2972			}
2973
2974			if (extent_logical + extent_len >
2975			    logic_start + map->stripe_len)
2976				extent_len = logic_start + map->stripe_len -
2977					     extent_logical;
2978
2979			scrub_parity_mark_sectors_data(sparity, extent_logical,
2980						       extent_len);
2981
2982			mapped_length = extent_len;
2983			ret = btrfs_map_block(fs_info, READ, extent_logical,
2984					      &mapped_length, &bbio, 0);
2985			if (!ret) {
2986				if (!bbio || mapped_length < extent_len)
2987					ret = -EIO;
2988			}
2989			if (ret) {
2990				btrfs_put_bbio(bbio);
2991				goto out;
2992			}
2993			extent_physical = bbio->stripes[0].physical;
2994			extent_mirror_num = bbio->mirror_num;
2995			extent_dev = bbio->stripes[0].dev;
2996			btrfs_put_bbio(bbio);
2997
2998			ret = btrfs_lookup_csums_range(csum_root,
2999						extent_logical,
3000						extent_logical + extent_len - 1,
3001						&sctx->csum_list, 1);
3002			if (ret)
3003				goto out;
3004
3005			ret = scrub_extent_for_parity(sparity, extent_logical,
3006						      extent_len,
3007						      extent_physical,
3008						      extent_dev, flags,
3009						      generation,
3010						      extent_mirror_num);
3011
3012			scrub_free_csums(sctx);
3013
3014			if (ret)
3015				goto out;
3016
3017			if (extent_logical + extent_len <
3018			    key.objectid + bytes) {
3019				logic_start += map->stripe_len;
3020
3021				if (logic_start >= logic_end) {
3022					stop_loop = 1;
3023					break;
3024				}
3025
3026				if (logic_start < key.objectid + bytes) {
3027					cond_resched();
3028					goto again;
3029				}
3030			}
3031next:
3032			path->slots[0]++;
3033		}
3034
3035		btrfs_release_path(path);
3036
3037		if (stop_loop)
3038			break;
3039
3040		logic_start += map->stripe_len;
3041	}
3042out:
3043	if (ret < 0)
3044		scrub_parity_mark_sectors_error(sparity, logic_start,
3045						logic_end - logic_start);
3046	scrub_parity_put(sparity);
3047	scrub_submit(sctx);
3048	mutex_lock(&sctx->wr_ctx.wr_lock);
3049	scrub_wr_submit(sctx);
3050	mutex_unlock(&sctx->wr_ctx.wr_lock);
3051
3052	btrfs_release_path(path);
3053	return ret < 0 ? ret : 0;
3054}
3055
3056static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
3057					   struct map_lookup *map,
3058					   struct btrfs_device *scrub_dev,
3059					   int num, u64 base, u64 length,
3060					   int is_dev_replace)
3061{
3062	struct btrfs_path *path, *ppath;
3063	struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;
3064	struct btrfs_root *root = fs_info->extent_root;
3065	struct btrfs_root *csum_root = fs_info->csum_root;
3066	struct btrfs_extent_item *extent;
3067	struct blk_plug plug;
3068	u64 flags;
3069	int ret;
3070	int slot;
 
3071	u64 nstripes;
3072	struct extent_buffer *l;
3073	struct btrfs_key key;
3074	u64 physical;
3075	u64 logical;
3076	u64 logic_end;
3077	u64 physical_end;
3078	u64 generation;
3079	int mirror_num;
3080	struct reada_control *reada1;
3081	struct reada_control *reada2;
3082	struct btrfs_key key_start;
3083	struct btrfs_key key_end;
 
3084	u64 increment = map->stripe_len;
3085	u64 offset;
3086	u64 extent_logical;
3087	u64 extent_physical;
3088	u64 extent_len;
3089	u64 stripe_logical;
3090	u64 stripe_end;
3091	struct btrfs_device *extent_dev;
3092	int extent_mirror_num;
3093	int stop_loop = 0;
3094
3095	physical = map->stripes[num].physical;
3096	offset = 0;
3097	nstripes = div_u64(length, map->stripe_len);
3098	if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
3099		offset = map->stripe_len * num;
3100		increment = map->stripe_len * map->num_stripes;
3101		mirror_num = 1;
3102	} else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
3103		int factor = map->num_stripes / map->sub_stripes;
3104		offset = map->stripe_len * (num / map->sub_stripes);
3105		increment = map->stripe_len * factor;
3106		mirror_num = num % map->sub_stripes + 1;
3107	} else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
3108		increment = map->stripe_len;
3109		mirror_num = num % map->num_stripes + 1;
3110	} else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
3111		increment = map->stripe_len;
3112		mirror_num = num % map->num_stripes + 1;
3113	} else if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
3114		get_raid56_logic_offset(physical, num, map, &offset, NULL);
3115		increment = map->stripe_len * nr_data_stripes(map);
3116		mirror_num = 1;
3117	} else {
3118		increment = map->stripe_len;
3119		mirror_num = 1;
3120	}
3121
3122	path = btrfs_alloc_path();
3123	if (!path)
3124		return -ENOMEM;
3125
3126	ppath = btrfs_alloc_path();
3127	if (!ppath) {
3128		btrfs_free_path(path);
3129		return -ENOMEM;
3130	}
3131
3132	/*
3133	 * work on commit root. The related disk blocks are static as
3134	 * long as COW is applied. This means, it is save to rewrite
3135	 * them to repair disk errors without any race conditions
3136	 */
3137	path->search_commit_root = 1;
3138	path->skip_locking = 1;
3139
3140	ppath->search_commit_root = 1;
3141	ppath->skip_locking = 1;
3142	/*
3143	 * trigger the readahead for extent tree csum tree and wait for
3144	 * completion. During readahead, the scrub is officially paused
3145	 * to not hold off transaction commits
3146	 */
3147	logical = base + offset;
3148	physical_end = physical + nstripes * map->stripe_len;
3149	if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
3150		get_raid56_logic_offset(physical_end, num,
3151					map, &logic_end, NULL);
3152		logic_end += base;
3153	} else {
3154		logic_end = logical + increment * nstripes;
3155	}
3156	wait_event(sctx->list_wait,
3157		   atomic_read(&sctx->bios_in_flight) == 0);
3158	scrub_blocked_if_needed(fs_info);
3159
3160	/* FIXME it might be better to start readahead at commit root */
3161	key_start.objectid = logical;
3162	key_start.type = BTRFS_EXTENT_ITEM_KEY;
3163	key_start.offset = (u64)0;
3164	key_end.objectid = logic_end;
3165	key_end.type = BTRFS_METADATA_ITEM_KEY;
3166	key_end.offset = (u64)-1;
3167	reada1 = btrfs_reada_add(root, &key_start, &key_end);
3168
3169	key_start.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
3170	key_start.type = BTRFS_EXTENT_CSUM_KEY;
3171	key_start.offset = logical;
3172	key_end.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
3173	key_end.type = BTRFS_EXTENT_CSUM_KEY;
3174	key_end.offset = logic_end;
3175	reada2 = btrfs_reada_add(csum_root, &key_start, &key_end);
3176
3177	if (!IS_ERR(reada1))
3178		btrfs_reada_wait(reada1);
3179	if (!IS_ERR(reada2))
3180		btrfs_reada_wait(reada2);
3181
 
 
 
 
 
 
 
 
 
 
3182
3183	/*
3184	 * collect all data csums for the stripe to avoid seeking during
3185	 * the scrub. This might currently (crc32) end up to be about 1MB
3186	 */
3187	blk_start_plug(&plug);
3188
3189	/*
3190	 * now find all extents for each stripe and scrub them
3191	 */
 
 
3192	ret = 0;
3193	while (physical < physical_end) {
3194		/*
3195		 * canceled?
3196		 */
3197		if (atomic_read(&fs_info->scrub_cancel_req) ||
3198		    atomic_read(&sctx->cancel_req)) {
3199			ret = -ECANCELED;
3200			goto out;
3201		}
3202		/*
3203		 * check to see if we have to pause
3204		 */
3205		if (atomic_read(&fs_info->scrub_pause_req)) {
3206			/* push queued extents */
3207			atomic_set(&sctx->wr_ctx.flush_all_writes, 1);
3208			scrub_submit(sctx);
3209			mutex_lock(&sctx->wr_ctx.wr_lock);
3210			scrub_wr_submit(sctx);
3211			mutex_unlock(&sctx->wr_ctx.wr_lock);
3212			wait_event(sctx->list_wait,
3213				   atomic_read(&sctx->bios_in_flight) == 0);
3214			atomic_set(&sctx->wr_ctx.flush_all_writes, 0);
3215			scrub_blocked_if_needed(fs_info);
3216		}
3217
3218		if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
3219			ret = get_raid56_logic_offset(physical, num, map,
3220						      &logical,
3221						      &stripe_logical);
3222			logical += base;
3223			if (ret) {
3224				/* it is parity strip */
3225				stripe_logical += base;
3226				stripe_end = stripe_logical + increment;
3227				ret = scrub_raid56_parity(sctx, map, scrub_dev,
3228							  ppath, stripe_logical,
3229							  stripe_end);
3230				if (ret)
3231					goto out;
3232				goto skip;
3233			}
3234		}
3235
3236		if (btrfs_fs_incompat(fs_info, SKINNY_METADATA))
3237			key.type = BTRFS_METADATA_ITEM_KEY;
3238		else
3239			key.type = BTRFS_EXTENT_ITEM_KEY;
3240		key.objectid = logical;
3241		key.offset = (u64)-1;
 
3242
3243		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3244		if (ret < 0)
3245			goto out;
3246
3247		if (ret > 0) {
3248			ret = btrfs_previous_extent_item(root, path, 0);
 
3249			if (ret < 0)
3250				goto out;
3251			if (ret > 0) {
3252				/* there's no smaller item, so stick with the
3253				 * larger one */
3254				btrfs_release_path(path);
3255				ret = btrfs_search_slot(NULL, root, &key,
3256							path, 0, 0);
3257				if (ret < 0)
3258					goto out;
3259			}
3260		}
3261
3262		stop_loop = 0;
3263		while (1) {
3264			u64 bytes;
3265
3266			l = path->nodes[0];
3267			slot = path->slots[0];
3268			if (slot >= btrfs_header_nritems(l)) {
3269				ret = btrfs_next_leaf(root, path);
3270				if (ret == 0)
3271					continue;
3272				if (ret < 0)
3273					goto out;
3274
3275				stop_loop = 1;
3276				break;
3277			}
3278			btrfs_item_key_to_cpu(l, &key, slot);
3279
3280			if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3281			    key.type != BTRFS_METADATA_ITEM_KEY)
3282				goto next;
3283
3284			if (key.type == BTRFS_METADATA_ITEM_KEY)
3285				bytes = root->nodesize;
3286			else
3287				bytes = key.offset;
3288
3289			if (key.objectid + bytes <= logical)
3290				goto next;
3291
3292			if (key.objectid >= logical + map->stripe_len) {
3293				/* out of this device extent */
3294				if (key.objectid >= logic_end)
3295					stop_loop = 1;
3296				break;
3297			}
3298
3299			extent = btrfs_item_ptr(l, slot,
3300						struct btrfs_extent_item);
3301			flags = btrfs_extent_flags(l, extent);
3302			generation = btrfs_extent_generation(l, extent);
3303
3304			if ((flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) &&
3305			    (key.objectid < logical ||
3306			     key.objectid + bytes >
3307			     logical + map->stripe_len)) {
3308				btrfs_err(fs_info,
3309					   "scrub: tree block %llu spanning "
3310					   "stripes, ignored. logical=%llu",
3311				       key.objectid, logical);
3312				spin_lock(&sctx->stat_lock);
3313				sctx->stat.uncorrectable_errors++;
3314				spin_unlock(&sctx->stat_lock);
3315				goto next;
3316			}
3317
3318again:
3319			extent_logical = key.objectid;
3320			extent_len = bytes;
3321
3322			/*
3323			 * trim extent to this stripe
3324			 */
3325			if (extent_logical < logical) {
3326				extent_len -= logical - extent_logical;
3327				extent_logical = logical;
3328			}
3329			if (extent_logical + extent_len >
3330			    logical + map->stripe_len) {
3331				extent_len = logical + map->stripe_len -
3332					     extent_logical;
3333			}
3334
3335			extent_physical = extent_logical - logical + physical;
3336			extent_dev = scrub_dev;
3337			extent_mirror_num = mirror_num;
3338			if (is_dev_replace)
3339				scrub_remap_extent(fs_info, extent_logical,
3340						   extent_len, &extent_physical,
3341						   &extent_dev,
3342						   &extent_mirror_num);
3343
3344			ret = btrfs_lookup_csums_range(csum_root,
3345						       extent_logical,
3346						       extent_logical +
3347						       extent_len - 1,
3348						       &sctx->csum_list, 1);
3349			if (ret)
3350				goto out;
3351
3352			ret = scrub_extent(sctx, extent_logical, extent_len,
3353					   extent_physical, extent_dev, flags,
3354					   generation, extent_mirror_num,
3355					   extent_logical - logical + physical);
3356
3357			scrub_free_csums(sctx);
3358
3359			if (ret)
3360				goto out;
3361
3362			if (extent_logical + extent_len <
3363			    key.objectid + bytes) {
3364				if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
3365					/*
3366					 * loop until we find next data stripe
3367					 * or we have finished all stripes.
3368					 */
3369loop:
3370					physical += map->stripe_len;
3371					ret = get_raid56_logic_offset(physical,
3372							num, map, &logical,
3373							&stripe_logical);
3374					logical += base;
3375
3376					if (ret && physical < physical_end) {
3377						stripe_logical += base;
3378						stripe_end = stripe_logical +
3379								increment;
3380						ret = scrub_raid56_parity(sctx,
3381							map, scrub_dev, ppath,
3382							stripe_logical,
3383							stripe_end);
3384						if (ret)
3385							goto out;
3386						goto loop;
3387					}
3388				} else {
3389					physical += map->stripe_len;
3390					logical += increment;
3391				}
3392				if (logical < key.objectid + bytes) {
3393					cond_resched();
3394					goto again;
3395				}
3396
3397				if (physical >= physical_end) {
3398					stop_loop = 1;
3399					break;
3400				}
3401			}
3402next:
3403			path->slots[0]++;
3404		}
3405		btrfs_release_path(path);
3406skip:
3407		logical += increment;
3408		physical += map->stripe_len;
3409		spin_lock(&sctx->stat_lock);
3410		if (stop_loop)
3411			sctx->stat.last_physical = map->stripes[num].physical +
3412						   length;
3413		else
3414			sctx->stat.last_physical = physical;
3415		spin_unlock(&sctx->stat_lock);
3416		if (stop_loop)
3417			break;
3418	}
3419out:
3420	/* push queued extents */
3421	scrub_submit(sctx);
3422	mutex_lock(&sctx->wr_ctx.wr_lock);
3423	scrub_wr_submit(sctx);
3424	mutex_unlock(&sctx->wr_ctx.wr_lock);
3425
 
3426	blk_finish_plug(&plug);
3427	btrfs_free_path(path);
3428	btrfs_free_path(ppath);
3429	return ret < 0 ? ret : 0;
3430}
3431
3432static noinline_for_stack int scrub_chunk(struct scrub_ctx *sctx,
3433					  struct btrfs_device *scrub_dev,
3434					  u64 chunk_offset, u64 length,
3435					  u64 dev_offset,
3436					  struct btrfs_block_group_cache *cache,
3437					  int is_dev_replace)
3438{
3439	struct btrfs_mapping_tree *map_tree =
3440		&sctx->dev_root->fs_info->mapping_tree;
3441	struct map_lookup *map;
3442	struct extent_map *em;
3443	int i;
3444	int ret = 0;
3445
3446	read_lock(&map_tree->map_tree.lock);
3447	em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
3448	read_unlock(&map_tree->map_tree.lock);
3449
3450	if (!em) {
3451		/*
3452		 * Might have been an unused block group deleted by the cleaner
3453		 * kthread or relocation.
3454		 */
3455		spin_lock(&cache->lock);
3456		if (!cache->removed)
3457			ret = -EINVAL;
3458		spin_unlock(&cache->lock);
3459
3460		return ret;
3461	}
3462
3463	map = em->map_lookup;
3464	if (em->start != chunk_offset)
3465		goto out;
3466
3467	if (em->len < length)
3468		goto out;
3469
3470	for (i = 0; i < map->num_stripes; ++i) {
3471		if (map->stripes[i].dev->bdev == scrub_dev->bdev &&
3472		    map->stripes[i].physical == dev_offset) {
3473			ret = scrub_stripe(sctx, map, scrub_dev, i,
3474					   chunk_offset, length,
3475					   is_dev_replace);
3476			if (ret)
3477				goto out;
3478		}
3479	}
3480out:
3481	free_extent_map(em);
3482
3483	return ret;
3484}
3485
3486static noinline_for_stack
3487int scrub_enumerate_chunks(struct scrub_ctx *sctx,
3488			   struct btrfs_device *scrub_dev, u64 start, u64 end,
3489			   int is_dev_replace)
3490{
3491	struct btrfs_dev_extent *dev_extent = NULL;
3492	struct btrfs_path *path;
3493	struct btrfs_root *root = sctx->dev_root;
3494	struct btrfs_fs_info *fs_info = root->fs_info;
3495	u64 length;
 
 
3496	u64 chunk_offset;
3497	int ret = 0;
3498	int ro_set;
3499	int slot;
3500	struct extent_buffer *l;
3501	struct btrfs_key key;
3502	struct btrfs_key found_key;
3503	struct btrfs_block_group_cache *cache;
3504	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
3505
3506	path = btrfs_alloc_path();
3507	if (!path)
3508		return -ENOMEM;
3509
3510	path->reada = READA_FORWARD;
3511	path->search_commit_root = 1;
3512	path->skip_locking = 1;
3513
3514	key.objectid = scrub_dev->devid;
3515	key.offset = 0ull;
3516	key.type = BTRFS_DEV_EXTENT_KEY;
3517
 
3518	while (1) {
3519		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3520		if (ret < 0)
3521			break;
3522		if (ret > 0) {
3523			if (path->slots[0] >=
3524			    btrfs_header_nritems(path->nodes[0])) {
3525				ret = btrfs_next_leaf(root, path);
3526				if (ret < 0)
3527					break;
3528				if (ret > 0) {
3529					ret = 0;
3530					break;
3531				}
3532			} else {
3533				ret = 0;
3534			}
3535		}
3536
3537		l = path->nodes[0];
3538		slot = path->slots[0];
3539
3540		btrfs_item_key_to_cpu(l, &found_key, slot);
3541
3542		if (found_key.objectid != scrub_dev->devid)
3543			break;
3544
3545		if (found_key.type != BTRFS_DEV_EXTENT_KEY)
3546			break;
3547
3548		if (found_key.offset >= end)
3549			break;
3550
3551		if (found_key.offset < key.offset)
3552			break;
3553
3554		dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
3555		length = btrfs_dev_extent_length(l, dev_extent);
3556
3557		if (found_key.offset + length <= start)
3558			goto skip;
 
 
 
3559
 
 
3560		chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
3561
3562		/*
3563		 * get a reference on the corresponding block group to prevent
3564		 * the chunk from going away while we scrub it
3565		 */
3566		cache = btrfs_lookup_block_group(fs_info, chunk_offset);
3567
3568		/* some chunks are removed but not committed to disk yet,
3569		 * continue scrubbing */
3570		if (!cache)
3571			goto skip;
3572
3573		/*
3574		 * we need call btrfs_inc_block_group_ro() with scrubs_paused,
3575		 * to avoid deadlock caused by:
3576		 * btrfs_inc_block_group_ro()
3577		 * -> btrfs_wait_for_commit()
3578		 * -> btrfs_commit_transaction()
3579		 * -> btrfs_scrub_pause()
3580		 */
3581		scrub_pause_on(fs_info);
3582		ret = btrfs_inc_block_group_ro(root, cache);
3583		scrub_pause_off(fs_info);
3584
3585		if (ret == 0) {
3586			ro_set = 1;
3587		} else if (ret == -ENOSPC) {
3588			/*
3589			 * btrfs_inc_block_group_ro return -ENOSPC when it
3590			 * failed in creating new chunk for metadata.
3591			 * It is not a problem for scrub/replace, because
3592			 * metadata are always cowed, and our scrub paused
3593			 * commit_transactions.
3594			 */
3595			ro_set = 0;
3596		} else {
3597			btrfs_warn(fs_info, "failed setting block group ro, ret=%d\n",
3598				   ret);
3599			btrfs_put_block_group(cache);
3600			break;
3601		}
3602
3603		dev_replace->cursor_right = found_key.offset + length;
3604		dev_replace->cursor_left = found_key.offset;
3605		dev_replace->item_needs_writeback = 1;
3606		ret = scrub_chunk(sctx, scrub_dev, chunk_offset, length,
3607				  found_key.offset, cache, is_dev_replace);
3608
3609		/*
3610		 * flush, submit all pending read and write bios, afterwards
3611		 * wait for them.
3612		 * Note that in the dev replace case, a read request causes
3613		 * write requests that are submitted in the read completion
3614		 * worker. Therefore in the current situation, it is required
3615		 * that all write requests are flushed, so that all read and
3616		 * write requests are really completed when bios_in_flight
3617		 * changes to 0.
3618		 */
3619		atomic_set(&sctx->wr_ctx.flush_all_writes, 1);
3620		scrub_submit(sctx);
3621		mutex_lock(&sctx->wr_ctx.wr_lock);
3622		scrub_wr_submit(sctx);
3623		mutex_unlock(&sctx->wr_ctx.wr_lock);
3624
3625		wait_event(sctx->list_wait,
3626			   atomic_read(&sctx->bios_in_flight) == 0);
3627
3628		scrub_pause_on(fs_info);
3629
3630		/*
3631		 * must be called before we decrease @scrub_paused.
3632		 * make sure we don't block transaction commit while
3633		 * we are waiting pending workers finished.
3634		 */
3635		wait_event(sctx->list_wait,
3636			   atomic_read(&sctx->workers_pending) == 0);
3637		atomic_set(&sctx->wr_ctx.flush_all_writes, 0);
3638
3639		scrub_pause_off(fs_info);
3640
3641		if (ro_set)
3642			btrfs_dec_block_group_ro(root, cache);
3643
3644		/*
3645		 * We might have prevented the cleaner kthread from deleting
3646		 * this block group if it was already unused because we raced
3647		 * and set it to RO mode first. So add it back to the unused
3648		 * list, otherwise it might not ever be deleted unless a manual
3649		 * balance is triggered or it becomes used and unused again.
3650		 */
3651		spin_lock(&cache->lock);
3652		if (!cache->removed && !cache->ro && cache->reserved == 0 &&
3653		    btrfs_block_group_used(&cache->item) == 0) {
3654			spin_unlock(&cache->lock);
3655			spin_lock(&fs_info->unused_bgs_lock);
3656			if (list_empty(&cache->bg_list)) {
3657				btrfs_get_block_group(cache);
3658				list_add_tail(&cache->bg_list,
3659					      &fs_info->unused_bgs);
3660			}
3661			spin_unlock(&fs_info->unused_bgs_lock);
3662		} else {
3663			spin_unlock(&cache->lock);
3664		}
3665
3666		btrfs_put_block_group(cache);
3667		if (ret)
3668			break;
3669		if (is_dev_replace &&
3670		    atomic64_read(&dev_replace->num_write_errors) > 0) {
3671			ret = -EIO;
3672			break;
3673		}
3674		if (sctx->stat.malloc_errors > 0) {
3675			ret = -ENOMEM;
3676			break;
3677		}
3678
3679		dev_replace->cursor_left = dev_replace->cursor_right;
3680		dev_replace->item_needs_writeback = 1;
3681skip:
3682		key.offset = found_key.offset + length;
3683		btrfs_release_path(path);
3684	}
3685
3686	btrfs_free_path(path);
3687
3688	return ret;
 
 
 
 
3689}
3690
3691static noinline_for_stack int scrub_supers(struct scrub_ctx *sctx,
3692					   struct btrfs_device *scrub_dev)
3693{
3694	int	i;
3695	u64	bytenr;
3696	u64	gen;
3697	int	ret;
3698	struct btrfs_root *root = sctx->dev_root;
 
3699
3700	if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
3701		return -EIO;
3702
3703	/* Seed devices of a new filesystem has their own generation. */
3704	if (scrub_dev->fs_devices != root->fs_info->fs_devices)
3705		gen = scrub_dev->generation;
3706	else
3707		gen = root->fs_info->last_trans_committed;
3708
3709	for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
3710		bytenr = btrfs_sb_offset(i);
3711		if (bytenr + BTRFS_SUPER_INFO_SIZE >
3712		    scrub_dev->commit_total_bytes)
3713			break;
3714
3715		ret = scrub_pages(sctx, bytenr, BTRFS_SUPER_INFO_SIZE, bytenr,
3716				  scrub_dev, BTRFS_EXTENT_FLAG_SUPER, gen, i,
3717				  NULL, 1, bytenr);
3718		if (ret)
3719			return ret;
3720	}
3721	wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0);
3722
3723	return 0;
3724}
3725
3726/*
3727 * get a reference count on fs_info->scrub_workers. start worker if necessary
3728 */
3729static noinline_for_stack int scrub_workers_get(struct btrfs_fs_info *fs_info,
3730						int is_dev_replace)
3731{
3732	unsigned int flags = WQ_FREEZABLE | WQ_UNBOUND;
3733	int max_active = fs_info->thread_pool_size;
3734
 
3735	if (fs_info->scrub_workers_refcnt == 0) {
3736		if (is_dev_replace)
3737			fs_info->scrub_workers =
3738				btrfs_alloc_workqueue("scrub", flags,
3739						      1, 4);
3740		else
3741			fs_info->scrub_workers =
3742				btrfs_alloc_workqueue("scrub", flags,
3743						      max_active, 4);
3744		if (!fs_info->scrub_workers)
3745			goto fail_scrub_workers;
3746
3747		fs_info->scrub_wr_completion_workers =
3748			btrfs_alloc_workqueue("scrubwrc", flags,
3749					      max_active, 2);
3750		if (!fs_info->scrub_wr_completion_workers)
3751			goto fail_scrub_wr_completion_workers;
3752
3753		fs_info->scrub_nocow_workers =
3754			btrfs_alloc_workqueue("scrubnc", flags, 1, 0);
3755		if (!fs_info->scrub_nocow_workers)
3756			goto fail_scrub_nocow_workers;
3757		fs_info->scrub_parity_workers =
3758			btrfs_alloc_workqueue("scrubparity", flags,
3759					      max_active, 2);
3760		if (!fs_info->scrub_parity_workers)
3761			goto fail_scrub_parity_workers;
3762	}
3763	++fs_info->scrub_workers_refcnt;
3764	return 0;
 
3765
3766fail_scrub_parity_workers:
3767	btrfs_destroy_workqueue(fs_info->scrub_nocow_workers);
3768fail_scrub_nocow_workers:
3769	btrfs_destroy_workqueue(fs_info->scrub_wr_completion_workers);
3770fail_scrub_wr_completion_workers:
3771	btrfs_destroy_workqueue(fs_info->scrub_workers);
3772fail_scrub_workers:
3773	return -ENOMEM;
3774}
3775
3776static noinline_for_stack void scrub_workers_put(struct btrfs_fs_info *fs_info)
3777{
3778	if (--fs_info->scrub_workers_refcnt == 0) {
3779		btrfs_destroy_workqueue(fs_info->scrub_workers);
3780		btrfs_destroy_workqueue(fs_info->scrub_wr_completion_workers);
3781		btrfs_destroy_workqueue(fs_info->scrub_nocow_workers);
3782		btrfs_destroy_workqueue(fs_info->scrub_parity_workers);
3783	}
3784	WARN_ON(fs_info->scrub_workers_refcnt < 0);
 
3785}
3786
3787int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
3788		    u64 end, struct btrfs_scrub_progress *progress,
3789		    int readonly, int is_dev_replace)
3790{
3791	struct scrub_ctx *sctx;
 
3792	int ret;
3793	struct btrfs_device *dev;
3794	struct rcu_string *name;
3795
3796	if (btrfs_fs_closing(fs_info))
 
 
 
 
 
 
 
 
 
3797		return -EINVAL;
 
3798
3799	if (fs_info->chunk_root->nodesize > BTRFS_STRIPE_LEN) {
3800		/*
3801		 * in this case scrub is unable to calculate the checksum
3802		 * the way scrub is implemented. Do not handle this
3803		 * situation at all because it won't ever happen.
3804		 */
3805		btrfs_err(fs_info,
3806			   "scrub: size assumption nodesize <= BTRFS_STRIPE_LEN (%d <= %d) fails",
3807		       fs_info->chunk_root->nodesize, BTRFS_STRIPE_LEN);
3808		return -EINVAL;
3809	}
3810
3811	if (fs_info->chunk_root->sectorsize != PAGE_SIZE) {
3812		/* not supported for data w/o checksums */
3813		btrfs_err(fs_info,
3814			   "scrub: size assumption sectorsize != PAGE_SIZE "
3815			   "(%d != %lu) fails",
3816		       fs_info->chunk_root->sectorsize, PAGE_SIZE);
3817		return -EINVAL;
3818	}
3819
3820	if (fs_info->chunk_root->nodesize >
3821	    PAGE_SIZE * SCRUB_MAX_PAGES_PER_BLOCK ||
3822	    fs_info->chunk_root->sectorsize >
3823	    PAGE_SIZE * SCRUB_MAX_PAGES_PER_BLOCK) {
3824		/*
3825		 * would exhaust the array bounds of pagev member in
3826		 * struct scrub_block
3827		 */
3828		btrfs_err(fs_info, "scrub: size assumption nodesize and sectorsize "
3829			   "<= SCRUB_MAX_PAGES_PER_BLOCK (%d <= %d && %d <= %d) fails",
3830		       fs_info->chunk_root->nodesize,
3831		       SCRUB_MAX_PAGES_PER_BLOCK,
3832		       fs_info->chunk_root->sectorsize,
3833		       SCRUB_MAX_PAGES_PER_BLOCK);
3834		return -EINVAL;
3835	}
3836
 
 
 
3837
3838	mutex_lock(&fs_info->fs_devices->device_list_mutex);
3839	dev = btrfs_find_device(fs_info, devid, NULL, NULL);
3840	if (!dev || (dev->missing && !is_dev_replace)) {
3841		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
 
3842		return -ENODEV;
3843	}
3844
3845	if (!is_dev_replace && !readonly && !dev->writeable) {
3846		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3847		rcu_read_lock();
3848		name = rcu_dereference(dev->name);
3849		btrfs_err(fs_info, "scrub: device %s is not writable",
3850			  name->str);
3851		rcu_read_unlock();
3852		return -EROFS;
3853	}
3854
3855	mutex_lock(&fs_info->scrub_lock);
3856	if (!dev->in_fs_metadata || dev->is_tgtdev_for_dev_replace) {
3857		mutex_unlock(&fs_info->scrub_lock);
3858		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3859		return -EIO;
3860	}
3861
3862	btrfs_dev_replace_lock(&fs_info->dev_replace, 0);
3863	if (dev->scrub_device ||
3864	    (!is_dev_replace &&
3865	     btrfs_dev_replace_is_ongoing(&fs_info->dev_replace))) {
3866		btrfs_dev_replace_unlock(&fs_info->dev_replace, 0);
3867		mutex_unlock(&fs_info->scrub_lock);
3868		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3869		return -EINPROGRESS;
 
3870	}
3871	btrfs_dev_replace_unlock(&fs_info->dev_replace, 0);
3872
3873	ret = scrub_workers_get(fs_info, is_dev_replace);
3874	if (ret) {
3875		mutex_unlock(&fs_info->scrub_lock);
3876		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3877		return ret;
 
3878	}
3879
3880	sctx = scrub_setup_ctx(dev, is_dev_replace);
3881	if (IS_ERR(sctx)) {
3882		mutex_unlock(&fs_info->scrub_lock);
3883		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3884		scrub_workers_put(fs_info);
3885		return PTR_ERR(sctx);
3886	}
3887	sctx->readonly = readonly;
3888	dev->scrub_device = sctx;
3889	mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3890
3891	/*
3892	 * checking @scrub_pause_req here, we can avoid
3893	 * race between committing transaction and scrubbing.
3894	 */
3895	__scrub_blocked_if_needed(fs_info);
3896	atomic_inc(&fs_info->scrubs_running);
3897	mutex_unlock(&fs_info->scrub_lock);
 
3898
3899	if (!is_dev_replace) {
3900		/*
3901		 * by holding device list mutex, we can
3902		 * kick off writing super in log tree sync.
3903		 */
3904		mutex_lock(&fs_info->fs_devices->device_list_mutex);
3905		ret = scrub_supers(sctx, dev);
3906		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
3907	}
3908
3909	if (!ret)
3910		ret = scrub_enumerate_chunks(sctx, dev, start, end,
3911					     is_dev_replace);
3912
3913	wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0);
3914	atomic_dec(&fs_info->scrubs_running);
3915	wake_up(&fs_info->scrub_pause_wait);
3916
3917	wait_event(sctx->list_wait, atomic_read(&sctx->workers_pending) == 0);
3918
3919	if (progress)
3920		memcpy(progress, &sctx->stat, sizeof(*progress));
3921
3922	mutex_lock(&fs_info->scrub_lock);
3923	dev->scrub_device = NULL;
3924	scrub_workers_put(fs_info);
3925	mutex_unlock(&fs_info->scrub_lock);
3926
3927	scrub_put_ctx(sctx);
 
3928
3929	return ret;
3930}
3931
3932void btrfs_scrub_pause(struct btrfs_root *root)
3933{
3934	struct btrfs_fs_info *fs_info = root->fs_info;
3935
3936	mutex_lock(&fs_info->scrub_lock);
3937	atomic_inc(&fs_info->scrub_pause_req);
3938	while (atomic_read(&fs_info->scrubs_paused) !=
3939	       atomic_read(&fs_info->scrubs_running)) {
3940		mutex_unlock(&fs_info->scrub_lock);
3941		wait_event(fs_info->scrub_pause_wait,
3942			   atomic_read(&fs_info->scrubs_paused) ==
3943			   atomic_read(&fs_info->scrubs_running));
3944		mutex_lock(&fs_info->scrub_lock);
3945	}
3946	mutex_unlock(&fs_info->scrub_lock);
3947}
3948
3949void btrfs_scrub_continue(struct btrfs_root *root)
3950{
3951	struct btrfs_fs_info *fs_info = root->fs_info;
3952
3953	atomic_dec(&fs_info->scrub_pause_req);
3954	wake_up(&fs_info->scrub_pause_wait);
3955}
3956
3957int btrfs_scrub_cancel(struct btrfs_fs_info *fs_info)
3958{
 
 
 
 
 
 
 
 
 
 
 
3959	mutex_lock(&fs_info->scrub_lock);
3960	if (!atomic_read(&fs_info->scrubs_running)) {
3961		mutex_unlock(&fs_info->scrub_lock);
3962		return -ENOTCONN;
3963	}
3964
3965	atomic_inc(&fs_info->scrub_cancel_req);
3966	while (atomic_read(&fs_info->scrubs_running)) {
3967		mutex_unlock(&fs_info->scrub_lock);
3968		wait_event(fs_info->scrub_pause_wait,
3969			   atomic_read(&fs_info->scrubs_running) == 0);
3970		mutex_lock(&fs_info->scrub_lock);
3971	}
3972	atomic_dec(&fs_info->scrub_cancel_req);
3973	mutex_unlock(&fs_info->scrub_lock);
3974
3975	return 0;
3976}
3977
3978int btrfs_scrub_cancel_dev(struct btrfs_fs_info *fs_info,
3979			   struct btrfs_device *dev)
 
 
 
 
3980{
3981	struct scrub_ctx *sctx;
 
3982
3983	mutex_lock(&fs_info->scrub_lock);
3984	sctx = dev->scrub_device;
3985	if (!sctx) {
3986		mutex_unlock(&fs_info->scrub_lock);
3987		return -ENOTCONN;
3988	}
3989	atomic_inc(&sctx->cancel_req);
3990	while (dev->scrub_device) {
3991		mutex_unlock(&fs_info->scrub_lock);
3992		wait_event(fs_info->scrub_pause_wait,
3993			   dev->scrub_device == NULL);
3994		mutex_lock(&fs_info->scrub_lock);
3995	}
3996	mutex_unlock(&fs_info->scrub_lock);
3997
3998	return 0;
3999}
4000
4001int btrfs_scrub_progress(struct btrfs_root *root, u64 devid,
4002			 struct btrfs_scrub_progress *progress)
4003{
 
4004	struct btrfs_device *dev;
4005	struct scrub_ctx *sctx = NULL;
4006
4007	mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
4008	dev = btrfs_find_device(root->fs_info, devid, NULL, NULL);
4009	if (dev)
4010		sctx = dev->scrub_device;
4011	if (sctx)
4012		memcpy(progress, &sctx->stat, sizeof(*progress));
4013	mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
4014
4015	return dev ? (sctx ? 0 : -ENOTCONN) : -ENODEV;
4016}
4017
4018static void scrub_remap_extent(struct btrfs_fs_info *fs_info,
4019			       u64 extent_logical, u64 extent_len,
4020			       u64 *extent_physical,
4021			       struct btrfs_device **extent_dev,
4022			       int *extent_mirror_num)
4023{
4024	u64 mapped_length;
4025	struct btrfs_bio *bbio = NULL;
4026	int ret;
4027
4028	mapped_length = extent_len;
4029	ret = btrfs_map_block(fs_info, READ, extent_logical,
4030			      &mapped_length, &bbio, 0);
4031	if (ret || !bbio || mapped_length < extent_len ||
4032	    !bbio->stripes[0].dev->bdev) {
4033		btrfs_put_bbio(bbio);
4034		return;
4035	}
4036
4037	*extent_physical = bbio->stripes[0].physical;
4038	*extent_mirror_num = bbio->mirror_num;
4039	*extent_dev = bbio->stripes[0].dev;
4040	btrfs_put_bbio(bbio);
4041}
4042
4043static int scrub_setup_wr_ctx(struct scrub_ctx *sctx,
4044			      struct scrub_wr_ctx *wr_ctx,
4045			      struct btrfs_fs_info *fs_info,
4046			      struct btrfs_device *dev,
4047			      int is_dev_replace)
4048{
4049	WARN_ON(wr_ctx->wr_curr_bio != NULL);
4050
4051	mutex_init(&wr_ctx->wr_lock);
4052	wr_ctx->wr_curr_bio = NULL;
4053	if (!is_dev_replace)
4054		return 0;
4055
4056	WARN_ON(!dev->bdev);
4057	wr_ctx->pages_per_wr_bio = SCRUB_PAGES_PER_WR_BIO;
4058	wr_ctx->tgtdev = dev;
4059	atomic_set(&wr_ctx->flush_all_writes, 0);
4060	return 0;
4061}
4062
4063static void scrub_free_wr_ctx(struct scrub_wr_ctx *wr_ctx)
4064{
4065	mutex_lock(&wr_ctx->wr_lock);
4066	kfree(wr_ctx->wr_curr_bio);
4067	wr_ctx->wr_curr_bio = NULL;
4068	mutex_unlock(&wr_ctx->wr_lock);
4069}
4070
4071static int copy_nocow_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
4072			    int mirror_num, u64 physical_for_dev_replace)
4073{
4074	struct scrub_copy_nocow_ctx *nocow_ctx;
4075	struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;
4076
4077	nocow_ctx = kzalloc(sizeof(*nocow_ctx), GFP_NOFS);
4078	if (!nocow_ctx) {
4079		spin_lock(&sctx->stat_lock);
4080		sctx->stat.malloc_errors++;
4081		spin_unlock(&sctx->stat_lock);
4082		return -ENOMEM;
4083	}
4084
4085	scrub_pending_trans_workers_inc(sctx);
4086
4087	nocow_ctx->sctx = sctx;
4088	nocow_ctx->logical = logical;
4089	nocow_ctx->len = len;
4090	nocow_ctx->mirror_num = mirror_num;
4091	nocow_ctx->physical_for_dev_replace = physical_for_dev_replace;
4092	btrfs_init_work(&nocow_ctx->work, btrfs_scrubnc_helper,
4093			copy_nocow_pages_worker, NULL, NULL);
4094	INIT_LIST_HEAD(&nocow_ctx->inodes);
4095	btrfs_queue_work(fs_info->scrub_nocow_workers,
4096			 &nocow_ctx->work);
4097
4098	return 0;
4099}
4100
4101static int record_inode_for_nocow(u64 inum, u64 offset, u64 root, void *ctx)
4102{
4103	struct scrub_copy_nocow_ctx *nocow_ctx = ctx;
4104	struct scrub_nocow_inode *nocow_inode;
4105
4106	nocow_inode = kzalloc(sizeof(*nocow_inode), GFP_NOFS);
4107	if (!nocow_inode)
4108		return -ENOMEM;
4109	nocow_inode->inum = inum;
4110	nocow_inode->offset = offset;
4111	nocow_inode->root = root;
4112	list_add_tail(&nocow_inode->list, &nocow_ctx->inodes);
4113	return 0;
4114}
4115
4116#define COPY_COMPLETE 1
4117
4118static void copy_nocow_pages_worker(struct btrfs_work *work)
4119{
4120	struct scrub_copy_nocow_ctx *nocow_ctx =
4121		container_of(work, struct scrub_copy_nocow_ctx, work);
4122	struct scrub_ctx *sctx = nocow_ctx->sctx;
4123	u64 logical = nocow_ctx->logical;
4124	u64 len = nocow_ctx->len;
4125	int mirror_num = nocow_ctx->mirror_num;
4126	u64 physical_for_dev_replace = nocow_ctx->physical_for_dev_replace;
4127	int ret;
4128	struct btrfs_trans_handle *trans = NULL;
4129	struct btrfs_fs_info *fs_info;
4130	struct btrfs_path *path;
4131	struct btrfs_root *root;
4132	int not_written = 0;
4133
4134	fs_info = sctx->dev_root->fs_info;
4135	root = fs_info->extent_root;
4136
4137	path = btrfs_alloc_path();
4138	if (!path) {
4139		spin_lock(&sctx->stat_lock);
4140		sctx->stat.malloc_errors++;
4141		spin_unlock(&sctx->stat_lock);
4142		not_written = 1;
4143		goto out;
4144	}
4145
4146	trans = btrfs_join_transaction(root);
4147	if (IS_ERR(trans)) {
4148		not_written = 1;
4149		goto out;
4150	}
4151
4152	ret = iterate_inodes_from_logical(logical, fs_info, path,
4153					  record_inode_for_nocow, nocow_ctx);
4154	if (ret != 0 && ret != -ENOENT) {
4155		btrfs_warn(fs_info, "iterate_inodes_from_logical() failed: log %llu, "
4156			"phys %llu, len %llu, mir %u, ret %d",
4157			logical, physical_for_dev_replace, len, mirror_num,
4158			ret);
4159		not_written = 1;
4160		goto out;
4161	}
4162
4163	btrfs_end_transaction(trans, root);
4164	trans = NULL;
4165	while (!list_empty(&nocow_ctx->inodes)) {
4166		struct scrub_nocow_inode *entry;
4167		entry = list_first_entry(&nocow_ctx->inodes,
4168					 struct scrub_nocow_inode,
4169					 list);
4170		list_del_init(&entry->list);
4171		ret = copy_nocow_pages_for_inode(entry->inum, entry->offset,
4172						 entry->root, nocow_ctx);
4173		kfree(entry);
4174		if (ret == COPY_COMPLETE) {
4175			ret = 0;
4176			break;
4177		} else if (ret) {
4178			break;
4179		}
4180	}
4181out:
4182	while (!list_empty(&nocow_ctx->inodes)) {
4183		struct scrub_nocow_inode *entry;
4184		entry = list_first_entry(&nocow_ctx->inodes,
4185					 struct scrub_nocow_inode,
4186					 list);
4187		list_del_init(&entry->list);
4188		kfree(entry);
4189	}
4190	if (trans && !IS_ERR(trans))
4191		btrfs_end_transaction(trans, root);
4192	if (not_written)
4193		btrfs_dev_replace_stats_inc(&fs_info->dev_replace.
4194					    num_uncorrectable_read_errors);
4195
4196	btrfs_free_path(path);
4197	kfree(nocow_ctx);
4198
4199	scrub_pending_trans_workers_dec(sctx);
4200}
4201
4202static int check_extent_to_block(struct inode *inode, u64 start, u64 len,
4203				 u64 logical)
4204{
4205	struct extent_state *cached_state = NULL;
4206	struct btrfs_ordered_extent *ordered;
4207	struct extent_io_tree *io_tree;
4208	struct extent_map *em;
4209	u64 lockstart = start, lockend = start + len - 1;
4210	int ret = 0;
4211
4212	io_tree = &BTRFS_I(inode)->io_tree;
4213
4214	lock_extent_bits(io_tree, lockstart, lockend, &cached_state);
4215	ordered = btrfs_lookup_ordered_range(inode, lockstart, len);
4216	if (ordered) {
4217		btrfs_put_ordered_extent(ordered);
4218		ret = 1;
4219		goto out_unlock;
4220	}
4221
4222	em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
4223	if (IS_ERR(em)) {
4224		ret = PTR_ERR(em);
4225		goto out_unlock;
4226	}
4227
4228	/*
4229	 * This extent does not actually cover the logical extent anymore,
4230	 * move on to the next inode.
4231	 */
4232	if (em->block_start > logical ||
4233	    em->block_start + em->block_len < logical + len) {
4234		free_extent_map(em);
4235		ret = 1;
4236		goto out_unlock;
4237	}
4238	free_extent_map(em);
4239
4240out_unlock:
4241	unlock_extent_cached(io_tree, lockstart, lockend, &cached_state,
4242			     GFP_NOFS);
4243	return ret;
4244}
4245
4246static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root,
4247				      struct scrub_copy_nocow_ctx *nocow_ctx)
4248{
4249	struct btrfs_fs_info *fs_info = nocow_ctx->sctx->dev_root->fs_info;
4250	struct btrfs_key key;
4251	struct inode *inode;
4252	struct page *page;
4253	struct btrfs_root *local_root;
4254	struct extent_io_tree *io_tree;
4255	u64 physical_for_dev_replace;
4256	u64 nocow_ctx_logical;
4257	u64 len = nocow_ctx->len;
4258	unsigned long index;
4259	int srcu_index;
4260	int ret = 0;
4261	int err = 0;
4262
4263	key.objectid = root;
4264	key.type = BTRFS_ROOT_ITEM_KEY;
4265	key.offset = (u64)-1;
4266
4267	srcu_index = srcu_read_lock(&fs_info->subvol_srcu);
4268
4269	local_root = btrfs_read_fs_root_no_name(fs_info, &key);
4270	if (IS_ERR(local_root)) {
4271		srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
4272		return PTR_ERR(local_root);
4273	}
4274
4275	key.type = BTRFS_INODE_ITEM_KEY;
4276	key.objectid = inum;
4277	key.offset = 0;
4278	inode = btrfs_iget(fs_info->sb, &key, local_root, NULL);
4279	srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
4280	if (IS_ERR(inode))
4281		return PTR_ERR(inode);
4282
4283	/* Avoid truncate/dio/punch hole.. */
4284	inode_lock(inode);
4285	inode_dio_wait(inode);
4286
4287	physical_for_dev_replace = nocow_ctx->physical_for_dev_replace;
4288	io_tree = &BTRFS_I(inode)->io_tree;
4289	nocow_ctx_logical = nocow_ctx->logical;
4290
4291	ret = check_extent_to_block(inode, offset, len, nocow_ctx_logical);
4292	if (ret) {
4293		ret = ret > 0 ? 0 : ret;
4294		goto out;
4295	}
 
 
4296
4297	while (len >= PAGE_SIZE) {
4298		index = offset >> PAGE_SHIFT;
4299again:
4300		page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
4301		if (!page) {
4302			btrfs_err(fs_info, "find_or_create_page() failed");
4303			ret = -ENOMEM;
4304			goto out;
4305		}
4306
4307		if (PageUptodate(page)) {
4308			if (PageDirty(page))
4309				goto next_page;
4310		} else {
4311			ClearPageError(page);
4312			err = extent_read_full_page(io_tree, page,
4313							   btrfs_get_extent,
4314							   nocow_ctx->mirror_num);
4315			if (err) {
4316				ret = err;
4317				goto next_page;
4318			}
4319
4320			lock_page(page);
4321			/*
4322			 * If the page has been remove from the page cache,
4323			 * the data on it is meaningless, because it may be
4324			 * old one, the new data may be written into the new
4325			 * page in the page cache.
4326			 */
4327			if (page->mapping != inode->i_mapping) {
4328				unlock_page(page);
4329				put_page(page);
4330				goto again;
4331			}
4332			if (!PageUptodate(page)) {
4333				ret = -EIO;
4334				goto next_page;
4335			}
4336		}
4337
4338		ret = check_extent_to_block(inode, offset, len,
4339					    nocow_ctx_logical);
4340		if (ret) {
4341			ret = ret > 0 ? 0 : ret;
4342			goto next_page;
4343		}
4344
4345		err = write_page_nocow(nocow_ctx->sctx,
4346				       physical_for_dev_replace, page);
4347		if (err)
4348			ret = err;
4349next_page:
4350		unlock_page(page);
4351		put_page(page);
4352
4353		if (ret)
4354			break;
4355
4356		offset += PAGE_SIZE;
4357		physical_for_dev_replace += PAGE_SIZE;
4358		nocow_ctx_logical += PAGE_SIZE;
4359		len -= PAGE_SIZE;
4360	}
4361	ret = COPY_COMPLETE;
4362out:
4363	inode_unlock(inode);
4364	iput(inode);
4365	return ret;
4366}
4367
4368static int write_page_nocow(struct scrub_ctx *sctx,
4369			    u64 physical_for_dev_replace, struct page *page)
4370{
4371	struct bio *bio;
4372	struct btrfs_device *dev;
4373	int ret;
4374
4375	dev = sctx->wr_ctx.tgtdev;
4376	if (!dev)
4377		return -EIO;
4378	if (!dev->bdev) {
4379		btrfs_warn_rl(dev->dev_root->fs_info,
4380			"scrub write_page_nocow(bdev == NULL) is unexpected");
4381		return -EIO;
4382	}
4383	bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
4384	if (!bio) {
4385		spin_lock(&sctx->stat_lock);
4386		sctx->stat.malloc_errors++;
4387		spin_unlock(&sctx->stat_lock);
4388		return -ENOMEM;
4389	}
4390	bio->bi_iter.bi_size = 0;
4391	bio->bi_iter.bi_sector = physical_for_dev_replace >> 9;
4392	bio->bi_bdev = dev->bdev;
4393	ret = bio_add_page(bio, page, PAGE_SIZE, 0);
4394	if (ret != PAGE_SIZE) {
4395leave_with_eio:
4396		bio_put(bio);
4397		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
4398		return -EIO;
4399	}
4400
4401	if (btrfsic_submit_bio_wait(WRITE_SYNC, bio))
4402		goto leave_with_eio;
4403
4404	bio_put(bio);
4405	return 0;
4406}