scrub.c 89.6 KB
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/*
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 * Copyright (C) 2011, 2012 STRATO.  All rights reserved.
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 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include <linux/blkdev.h>
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#include <linux/ratelimit.h>
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#include "ctree.h"
#include "volumes.h"
#include "disk-io.h"
#include "ordered-data.h"
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#include "transaction.h"
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#include "backref.h"
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#include "extent_io.h"
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#include "dev-replace.h"
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#include "check-integrity.h"
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#include "rcu-string.h"
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#include "raid56.h"
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/*
 * This is only the first step towards a full-features scrub. It reads all
 * extent and super block and verifies the checksums. In case a bad checksum
 * is found or the extent cannot be read, good data will be written back if
 * any can be found.
 *
 * Future enhancements:
 *  - In case an unrepairable extent is encountered, track which files are
 *    affected and report them
 *  - track and record media errors, throw out bad devices
 *  - add a mode to also read unallocated space
 */

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struct scrub_block;
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struct scrub_ctx;
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/*
 * the following three values only influence the performance.
 * The last one configures the number of parallel and outstanding I/O
 * operations. The first two values configure an upper limit for the number
 * of (dynamically allocated) pages that are added to a bio.
 */
#define SCRUB_PAGES_PER_RD_BIO	32	/* 128k per bio */
#define SCRUB_PAGES_PER_WR_BIO	32	/* 128k per bio */
#define SCRUB_BIOS_PER_SCTX	64	/* 8MB per device in flight */
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/*
 * the following value times PAGE_SIZE needs to be large enough to match the
 * largest node/leaf/sector size that shall be supported.
 * Values larger than BTRFS_STRIPE_LEN are not supported.
 */
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#define SCRUB_MAX_PAGES_PER_BLOCK	16	/* 64k per node/leaf/sector */
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struct scrub_page {
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	struct scrub_block	*sblock;
	struct page		*page;
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	struct btrfs_device	*dev;
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	u64			flags;  /* extent flags */
	u64			generation;
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	u64			logical;
	u64			physical;
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	u64			physical_for_dev_replace;
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	atomic_t		ref_count;
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	struct {
		unsigned int	mirror_num:8;
		unsigned int	have_csum:1;
		unsigned int	io_error:1;
	};
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	u8			csum[BTRFS_CSUM_SIZE];
};

struct scrub_bio {
	int			index;
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	struct scrub_ctx	*sctx;
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	struct btrfs_device	*dev;
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	struct bio		*bio;
	int			err;
	u64			logical;
	u64			physical;
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#if SCRUB_PAGES_PER_WR_BIO >= SCRUB_PAGES_PER_RD_BIO
	struct scrub_page	*pagev[SCRUB_PAGES_PER_WR_BIO];
#else
	struct scrub_page	*pagev[SCRUB_PAGES_PER_RD_BIO];
#endif
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	int			page_count;
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	int			next_free;
	struct btrfs_work	work;
};

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struct scrub_block {
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	struct scrub_page	*pagev[SCRUB_MAX_PAGES_PER_BLOCK];
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	int			page_count;
	atomic_t		outstanding_pages;
	atomic_t		ref_count; /* free mem on transition to zero */
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	struct scrub_ctx	*sctx;
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	struct {
		unsigned int	header_error:1;
		unsigned int	checksum_error:1;
		unsigned int	no_io_error_seen:1;
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		unsigned int	generation_error:1; /* also sets header_error */
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	};
};

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struct scrub_wr_ctx {
	struct scrub_bio *wr_curr_bio;
	struct btrfs_device *tgtdev;
	int pages_per_wr_bio; /* <= SCRUB_PAGES_PER_WR_BIO */
	atomic_t flush_all_writes;
	struct mutex wr_lock;
};

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struct scrub_ctx {
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	struct scrub_bio	*bios[SCRUB_BIOS_PER_SCTX];
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	struct btrfs_root	*dev_root;
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	int			first_free;
	int			curr;
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	atomic_t		bios_in_flight;
	atomic_t		workers_pending;
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	spinlock_t		list_lock;
	wait_queue_head_t	list_wait;
	u16			csum_size;
	struct list_head	csum_list;
	atomic_t		cancel_req;
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	int			readonly;
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	int			pages_per_rd_bio;
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	u32			sectorsize;
	u32			nodesize;
	u32			leafsize;
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	int			is_dev_replace;
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	struct scrub_wr_ctx	wr_ctx;
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	/*
	 * statistics
	 */
	struct btrfs_scrub_progress stat;
	spinlock_t		stat_lock;
};

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struct scrub_fixup_nodatasum {
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	struct scrub_ctx	*sctx;
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	struct btrfs_device	*dev;
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	u64			logical;
	struct btrfs_root	*root;
	struct btrfs_work	work;
	int			mirror_num;
};

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struct scrub_copy_nocow_ctx {
	struct scrub_ctx	*sctx;
	u64			logical;
	u64			len;
	int			mirror_num;
	u64			physical_for_dev_replace;
	struct btrfs_work	work;
};

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struct scrub_warning {
	struct btrfs_path	*path;
	u64			extent_item_size;
	char			*scratch_buf;
	char			*msg_buf;
	const char		*errstr;
	sector_t		sector;
	u64			logical;
	struct btrfs_device	*dev;
	int			msg_bufsize;
	int			scratch_bufsize;
};

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static void scrub_pending_bio_inc(struct scrub_ctx *sctx);
static void scrub_pending_bio_dec(struct scrub_ctx *sctx);
static void scrub_pending_trans_workers_inc(struct scrub_ctx *sctx);
static void scrub_pending_trans_workers_dec(struct scrub_ctx *sctx);
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static int scrub_handle_errored_block(struct scrub_block *sblock_to_check);
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static int scrub_setup_recheck_block(struct scrub_ctx *sctx,
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				     struct btrfs_fs_info *fs_info,
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				     struct scrub_block *original_sblock,
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				     u64 length, u64 logical,
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				     struct scrub_block *sblocks_for_recheck);
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static void scrub_recheck_block(struct btrfs_fs_info *fs_info,
				struct scrub_block *sblock, int is_metadata,
				int have_csum, u8 *csum, u64 generation,
				u16 csum_size);
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static void scrub_recheck_block_checksum(struct btrfs_fs_info *fs_info,
					 struct scrub_block *sblock,
					 int is_metadata, int have_csum,
					 const u8 *csum, u64 generation,
					 u16 csum_size);
static void scrub_complete_bio_end_io(struct bio *bio, int err);
static int scrub_repair_block_from_good_copy(struct scrub_block *sblock_bad,
					     struct scrub_block *sblock_good,
					     int force_write);
static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
					    struct scrub_block *sblock_good,
					    int page_num, int force_write);
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static void scrub_write_block_to_dev_replace(struct scrub_block *sblock);
static int scrub_write_page_to_dev_replace(struct scrub_block *sblock,
					   int page_num);
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static int scrub_checksum_data(struct scrub_block *sblock);
static int scrub_checksum_tree_block(struct scrub_block *sblock);
static int scrub_checksum_super(struct scrub_block *sblock);
static void scrub_block_get(struct scrub_block *sblock);
static void scrub_block_put(struct scrub_block *sblock);
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static void scrub_page_get(struct scrub_page *spage);
static void scrub_page_put(struct scrub_page *spage);
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static int scrub_add_page_to_rd_bio(struct scrub_ctx *sctx,
				    struct scrub_page *spage);
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static int scrub_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
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		       u64 physical, struct btrfs_device *dev, u64 flags,
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		       u64 gen, int mirror_num, u8 *csum, int force,
		       u64 physical_for_dev_replace);
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static void scrub_bio_end_io(struct bio *bio, int err);
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static void scrub_bio_end_io_worker(struct btrfs_work *work);
static void scrub_block_complete(struct scrub_block *sblock);
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static void scrub_remap_extent(struct btrfs_fs_info *fs_info,
			       u64 extent_logical, u64 extent_len,
			       u64 *extent_physical,
			       struct btrfs_device **extent_dev,
			       int *extent_mirror_num);
static int scrub_setup_wr_ctx(struct scrub_ctx *sctx,
			      struct scrub_wr_ctx *wr_ctx,
			      struct btrfs_fs_info *fs_info,
			      struct btrfs_device *dev,
			      int is_dev_replace);
static void scrub_free_wr_ctx(struct scrub_wr_ctx *wr_ctx);
static int scrub_add_page_to_wr_bio(struct scrub_ctx *sctx,
				    struct scrub_page *spage);
static void scrub_wr_submit(struct scrub_ctx *sctx);
static void scrub_wr_bio_end_io(struct bio *bio, int err);
static void scrub_wr_bio_end_io_worker(struct btrfs_work *work);
static int write_page_nocow(struct scrub_ctx *sctx,
			    u64 physical_for_dev_replace, struct page *page);
static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root,
				      void *ctx);
static int copy_nocow_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
			    int mirror_num, u64 physical_for_dev_replace);
static void copy_nocow_pages_worker(struct btrfs_work *work);
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static void scrub_pending_bio_inc(struct scrub_ctx *sctx)
{
	atomic_inc(&sctx->bios_in_flight);
}

static void scrub_pending_bio_dec(struct scrub_ctx *sctx)
{
	atomic_dec(&sctx->bios_in_flight);
	wake_up(&sctx->list_wait);
}

/*
 * used for workers that require transaction commits (i.e., for the
 * NOCOW case)
 */
static void scrub_pending_trans_workers_inc(struct scrub_ctx *sctx)
{
	struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;

	/*
	 * increment scrubs_running to prevent cancel requests from
	 * completing as long as a worker is running. we must also
	 * increment scrubs_paused to prevent deadlocking on pause
	 * requests used for transactions commits (as the worker uses a
	 * transaction context). it is safe to regard the worker
	 * as paused for all matters practical. effectively, we only
	 * avoid cancellation requests from completing.
	 */
	mutex_lock(&fs_info->scrub_lock);
	atomic_inc(&fs_info->scrubs_running);
	atomic_inc(&fs_info->scrubs_paused);
	mutex_unlock(&fs_info->scrub_lock);
	atomic_inc(&sctx->workers_pending);
}

/* used for workers that require transaction commits */
static void scrub_pending_trans_workers_dec(struct scrub_ctx *sctx)
{
	struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;

	/*
	 * see scrub_pending_trans_workers_inc() why we're pretending
	 * to be paused in the scrub counters
	 */
	mutex_lock(&fs_info->scrub_lock);
	atomic_dec(&fs_info->scrubs_running);
	atomic_dec(&fs_info->scrubs_paused);
	mutex_unlock(&fs_info->scrub_lock);
	atomic_dec(&sctx->workers_pending);
	wake_up(&fs_info->scrub_pause_wait);
	wake_up(&sctx->list_wait);
}

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static void scrub_free_csums(struct scrub_ctx *sctx)
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{
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	while (!list_empty(&sctx->csum_list)) {
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		struct btrfs_ordered_sum *sum;
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		sum = list_first_entry(&sctx->csum_list,
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				       struct btrfs_ordered_sum, list);
		list_del(&sum->list);
		kfree(sum);
	}
}

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static noinline_for_stack void scrub_free_ctx(struct scrub_ctx *sctx)
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{
	int i;

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	if (!sctx)
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		return;

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	scrub_free_wr_ctx(&sctx->wr_ctx);

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	/* this can happen when scrub is cancelled */
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	if (sctx->curr != -1) {
		struct scrub_bio *sbio = sctx->bios[sctx->curr];
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		for (i = 0; i < sbio->page_count; i++) {
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			WARN_ON(!sbio->pagev[i]->page);
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			scrub_block_put(sbio->pagev[i]->sblock);
		}
		bio_put(sbio->bio);
	}

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	for (i = 0; i < SCRUB_BIOS_PER_SCTX; ++i) {
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		struct scrub_bio *sbio = sctx->bios[i];
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		if (!sbio)
			break;
		kfree(sbio);
	}

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	scrub_free_csums(sctx);
	kfree(sctx);
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}

static noinline_for_stack
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struct scrub_ctx *scrub_setup_ctx(struct btrfs_device *dev, int is_dev_replace)
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{
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	struct scrub_ctx *sctx;
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	int		i;
	struct btrfs_fs_info *fs_info = dev->dev_root->fs_info;
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	int pages_per_rd_bio;
	int ret;
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	/*
	 * the setting of pages_per_rd_bio is correct for scrub but might
	 * be wrong for the dev_replace code where we might read from
	 * different devices in the initial huge bios. However, that
	 * code is able to correctly handle the case when adding a page
	 * to a bio fails.
	 */
	if (dev->bdev)
		pages_per_rd_bio = min_t(int, SCRUB_PAGES_PER_RD_BIO,
					 bio_get_nr_vecs(dev->bdev));
	else
		pages_per_rd_bio = SCRUB_PAGES_PER_RD_BIO;
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	sctx = kzalloc(sizeof(*sctx), GFP_NOFS);
	if (!sctx)
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		goto nomem;
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	sctx->is_dev_replace = is_dev_replace;
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	sctx->pages_per_rd_bio = pages_per_rd_bio;
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	sctx->curr = -1;
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	sctx->dev_root = dev->dev_root;
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	for (i = 0; i < SCRUB_BIOS_PER_SCTX; ++i) {
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		struct scrub_bio *sbio;

		sbio = kzalloc(sizeof(*sbio), GFP_NOFS);
		if (!sbio)
			goto nomem;
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		sctx->bios[i] = sbio;
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		sbio->index = i;
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		sbio->sctx = sctx;
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		sbio->page_count = 0;
		sbio->work.func = scrub_bio_end_io_worker;
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		if (i != SCRUB_BIOS_PER_SCTX - 1)
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			sctx->bios[i]->next_free = i + 1;
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		else
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			sctx->bios[i]->next_free = -1;
	}
	sctx->first_free = 0;
	sctx->nodesize = dev->dev_root->nodesize;
	sctx->leafsize = dev->dev_root->leafsize;
	sctx->sectorsize = dev->dev_root->sectorsize;
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	atomic_set(&sctx->bios_in_flight, 0);
	atomic_set(&sctx->workers_pending, 0);
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	atomic_set(&sctx->cancel_req, 0);
	sctx->csum_size = btrfs_super_csum_size(fs_info->super_copy);
	INIT_LIST_HEAD(&sctx->csum_list);

	spin_lock_init(&sctx->list_lock);
	spin_lock_init(&sctx->stat_lock);
	init_waitqueue_head(&sctx->list_wait);
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	ret = scrub_setup_wr_ctx(sctx, &sctx->wr_ctx, fs_info,
				 fs_info->dev_replace.tgtdev, is_dev_replace);
	if (ret) {
		scrub_free_ctx(sctx);
		return ERR_PTR(ret);
	}
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	return sctx;
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nomem:
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	scrub_free_ctx(sctx);
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	return ERR_PTR(-ENOMEM);
}

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static int scrub_print_warning_inode(u64 inum, u64 offset, u64 root,
				     void *warn_ctx)
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{
	u64 isize;
	u32 nlink;
	int ret;
	int i;
	struct extent_buffer *eb;
	struct btrfs_inode_item *inode_item;
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	struct scrub_warning *swarn = warn_ctx;
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	struct btrfs_fs_info *fs_info = swarn->dev->dev_root->fs_info;
	struct inode_fs_paths *ipath = NULL;
	struct btrfs_root *local_root;
	struct btrfs_key root_key;

	root_key.objectid = root;
	root_key.type = BTRFS_ROOT_ITEM_KEY;
	root_key.offset = (u64)-1;
	local_root = btrfs_read_fs_root_no_name(fs_info, &root_key);
	if (IS_ERR(local_root)) {
		ret = PTR_ERR(local_root);
		goto err;
	}

	ret = inode_item_info(inum, 0, local_root, swarn->path);
	if (ret) {
		btrfs_release_path(swarn->path);
		goto err;
	}

	eb = swarn->path->nodes[0];
	inode_item = btrfs_item_ptr(eb, swarn->path->slots[0],
					struct btrfs_inode_item);
	isize = btrfs_inode_size(eb, inode_item);
	nlink = btrfs_inode_nlink(eb, inode_item);
	btrfs_release_path(swarn->path);

	ipath = init_ipath(4096, local_root, swarn->path);
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	if (IS_ERR(ipath)) {
		ret = PTR_ERR(ipath);
		ipath = NULL;
		goto err;
	}
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	ret = paths_from_inode(inum, ipath);

	if (ret < 0)
		goto err;

	/*
	 * we deliberately ignore the bit ipath might have been too small to
	 * hold all of the paths here
	 */
	for (i = 0; i < ipath->fspath->elem_cnt; ++i)
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		printk_in_rcu(KERN_WARNING "btrfs: %s at logical %llu on dev "
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			"%s, sector %llu, root %llu, inode %llu, offset %llu, "
			"length %llu, links %u (path: %s)\n", swarn->errstr,
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			swarn->logical, rcu_str_deref(swarn->dev->name),
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			(unsigned long long)swarn->sector, root, inum, offset,
			min(isize - offset, (u64)PAGE_SIZE), nlink,
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			(char *)(unsigned long)ipath->fspath->val[i]);
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	free_ipath(ipath);
	return 0;

err:
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	printk_in_rcu(KERN_WARNING "btrfs: %s at logical %llu on dev "
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		"%s, sector %llu, root %llu, inode %llu, offset %llu: path "
		"resolving failed with ret=%d\n", swarn->errstr,
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		swarn->logical, rcu_str_deref(swarn->dev->name),
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		(unsigned long long)swarn->sector, root, inum, offset, ret);

	free_ipath(ipath);
	return 0;
}

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static void scrub_print_warning(const char *errstr, struct scrub_block *sblock)
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{
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	struct btrfs_device *dev;
	struct btrfs_fs_info *fs_info;
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	struct btrfs_path *path;
	struct btrfs_key found_key;
	struct extent_buffer *eb;
	struct btrfs_extent_item *ei;
	struct scrub_warning swarn;
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	unsigned long ptr = 0;
	u64 extent_item_pos;
	u64 flags = 0;
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	u64 ref_root;
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	u32 item_size;
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	u8 ref_level;
	const int bufsize = 4096;
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	int ret;
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	WARN_ON(sblock->page_count < 1);
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	dev = sblock->pagev[0]->dev;
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	fs_info = sblock->sctx->dev_root->fs_info;

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	path = btrfs_alloc_path();

	swarn.scratch_buf = kmalloc(bufsize, GFP_NOFS);
	swarn.msg_buf = kmalloc(bufsize, GFP_NOFS);
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	swarn.sector = (sblock->pagev[0]->physical) >> 9;
	swarn.logical = sblock->pagev[0]->logical;
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	swarn.errstr = errstr;
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	swarn.dev = NULL;
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	swarn.msg_bufsize = bufsize;
	swarn.scratch_bufsize = bufsize;

	if (!path || !swarn.scratch_buf || !swarn.msg_buf)
		goto out;

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	ret = extent_from_logical(fs_info, swarn.logical, path, &found_key,
				  &flags);
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	if (ret < 0)
		goto out;

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	extent_item_pos = swarn.logical - found_key.objectid;
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	swarn.extent_item_size = found_key.offset;

	eb = path->nodes[0];
	ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
	item_size = btrfs_item_size_nr(eb, path->slots[0]);

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	if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
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		do {
			ret = tree_backref_for_extent(&ptr, eb, ei, item_size,
							&ref_root, &ref_level);
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			printk_in_rcu(KERN_WARNING
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				"btrfs: %s at logical %llu on dev %s, "
552
				"sector %llu: metadata %s (level %d) in tree "
553 554
				"%llu\n", errstr, swarn.logical,
				rcu_str_deref(dev->name),
555 556 557 558 559
				(unsigned long long)swarn.sector,
				ref_level ? "node" : "leaf",
				ret < 0 ? -1 : ref_level,
				ret < 0 ? -1 : ref_root);
		} while (ret != 1);
560
		btrfs_release_path(path);
561
	} else {
562
		btrfs_release_path(path);
563
		swarn.path = path;
564
		swarn.dev = dev;
565 566
		iterate_extent_inodes(fs_info, found_key.objectid,
					extent_item_pos, 1,
567 568 569 570 571 572 573 574 575
					scrub_print_warning_inode, &swarn);
	}

out:
	btrfs_free_path(path);
	kfree(swarn.scratch_buf);
	kfree(swarn.msg_buf);
}

576
static int scrub_fixup_readpage(u64 inum, u64 offset, u64 root, void *fixup_ctx)
577
{
578
	struct page *page = NULL;
579
	unsigned long index;
580
	struct scrub_fixup_nodatasum *fixup = fixup_ctx;
581
	int ret;
582
	int corrected = 0;
583
	struct btrfs_key key;
584
	struct inode *inode = NULL;
585
	struct btrfs_fs_info *fs_info;
586 587
	u64 end = offset + PAGE_SIZE - 1;
	struct btrfs_root *local_root;
588
	int srcu_index;
589 590 591 592

	key.objectid = root;
	key.type = BTRFS_ROOT_ITEM_KEY;
	key.offset = (u64)-1;
593 594 595 596 597 598 599

	fs_info = fixup->root->fs_info;
	srcu_index = srcu_read_lock(&fs_info->subvol_srcu);

	local_root = btrfs_read_fs_root_no_name(fs_info, &key);
	if (IS_ERR(local_root)) {
		srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
600
		return PTR_ERR(local_root);
601
	}
602 603 604 605

	key.type = BTRFS_INODE_ITEM_KEY;
	key.objectid = inum;
	key.offset = 0;
606 607
	inode = btrfs_iget(fs_info->sb, &key, local_root, NULL);
	srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
608 609 610 611 612 613
	if (IS_ERR(inode))
		return PTR_ERR(inode);

	index = offset >> PAGE_CACHE_SHIFT;

	page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639
	if (!page) {
		ret = -ENOMEM;
		goto out;
	}

	if (PageUptodate(page)) {
		if (PageDirty(page)) {
			/*
			 * we need to write the data to the defect sector. the
			 * data that was in that sector is not in memory,
			 * because the page was modified. we must not write the
			 * modified page to that sector.
			 *
			 * TODO: what could be done here: wait for the delalloc
			 *       runner to write out that page (might involve
			 *       COW) and see whether the sector is still
			 *       referenced afterwards.
			 *
			 * For the meantime, we'll treat this error
			 * incorrectable, although there is a chance that a
			 * later scrub will find the bad sector again and that
			 * there's no dirty page in memory, then.
			 */
			ret = -EIO;
			goto out;
		}
640 641
		fs_info = BTRFS_I(inode)->root->fs_info;
		ret = repair_io_failure(fs_info, offset, PAGE_SIZE,
642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678
					fixup->logical, page,
					fixup->mirror_num);
		unlock_page(page);
		corrected = !ret;
	} else {
		/*
		 * we need to get good data first. the general readpage path
		 * will call repair_io_failure for us, we just have to make
		 * sure we read the bad mirror.
		 */
		ret = set_extent_bits(&BTRFS_I(inode)->io_tree, offset, end,
					EXTENT_DAMAGED, GFP_NOFS);
		if (ret) {
			/* set_extent_bits should give proper error */
			WARN_ON(ret > 0);
			if (ret > 0)
				ret = -EFAULT;
			goto out;
		}

		ret = extent_read_full_page(&BTRFS_I(inode)->io_tree, page,
						btrfs_get_extent,
						fixup->mirror_num);
		wait_on_page_locked(page);

		corrected = !test_range_bit(&BTRFS_I(inode)->io_tree, offset,
						end, EXTENT_DAMAGED, 0, NULL);
		if (!corrected)
			clear_extent_bits(&BTRFS_I(inode)->io_tree, offset, end,
						EXTENT_DAMAGED, GFP_NOFS);
	}

out:
	if (page)
		put_page(page);
	if (inode)
		iput(inode);
679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697

	if (ret < 0)
		return ret;

	if (ret == 0 && corrected) {
		/*
		 * we only need to call readpage for one of the inodes belonging
		 * to this extent. so make iterate_extent_inodes stop
		 */
		return 1;
	}

	return -EIO;
}

static void scrub_fixup_nodatasum(struct btrfs_work *work)
{
	int ret;
	struct scrub_fixup_nodatasum *fixup;
698
	struct scrub_ctx *sctx;
699 700 701 702 703 704
	struct btrfs_trans_handle *trans = NULL;
	struct btrfs_fs_info *fs_info;
	struct btrfs_path *path;
	int uncorrectable = 0;

	fixup = container_of(work, struct scrub_fixup_nodatasum, work);
705
	sctx = fixup->sctx;
706 707 708 709
	fs_info = fixup->root->fs_info;

	path = btrfs_alloc_path();
	if (!path) {
710 711 712
		spin_lock(&sctx->stat_lock);
		++sctx->stat.malloc_errors;
		spin_unlock(&sctx->stat_lock);
713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740
		uncorrectable = 1;
		goto out;
	}

	trans = btrfs_join_transaction(fixup->root);
	if (IS_ERR(trans)) {
		uncorrectable = 1;
		goto out;
	}

	/*
	 * the idea is to trigger a regular read through the standard path. we
	 * read a page from the (failed) logical address by specifying the
	 * corresponding copynum of the failed sector. thus, that readpage is
	 * expected to fail.
	 * that is the point where on-the-fly error correction will kick in
	 * (once it's finished) and rewrite the failed sector if a good copy
	 * can be found.
	 */
	ret = iterate_inodes_from_logical(fixup->logical, fixup->root->fs_info,
						path, scrub_fixup_readpage,
						fixup);
	if (ret < 0) {
		uncorrectable = 1;
		goto out;
	}
	WARN_ON(ret != 1);

741 742 743
	spin_lock(&sctx->stat_lock);
	++sctx->stat.corrected_errors;
	spin_unlock(&sctx->stat_lock);
744 745 746 747 748

out:
	if (trans && !IS_ERR(trans))
		btrfs_end_transaction(trans, fixup->root);
	if (uncorrectable) {
749 750 751
		spin_lock(&sctx->stat_lock);
		++sctx->stat.uncorrectable_errors;
		spin_unlock(&sctx->stat_lock);
752 753 754
		btrfs_dev_replace_stats_inc(
			&sctx->dev_root->fs_info->dev_replace.
			num_uncorrectable_read_errors);
755
		printk_ratelimited_in_rcu(KERN_ERR
756
			"btrfs: unable to fixup (nodatasum) error at logical %llu on dev %s\n",
757
			fixup->logical, rcu_str_deref(fixup->dev->name));
758 759 760 761 762
	}

	btrfs_free_path(path);
	kfree(fixup);

763
	scrub_pending_trans_workers_dec(sctx);
764 765
}

A
Arne Jansen 已提交
766
/*
767 768 769 770 771 772
 * scrub_handle_errored_block gets called when either verification of the
 * pages failed or the bio failed to read, e.g. with EIO. In the latter
 * case, this function handles all pages in the bio, even though only one
 * may be bad.
 * The goal of this function is to repair the errored block by using the
 * contents of one of the mirrors.
A
Arne Jansen 已提交
773
 */
774
static int scrub_handle_errored_block(struct scrub_block *sblock_to_check)
A
Arne Jansen 已提交
775
{
776
	struct scrub_ctx *sctx = sblock_to_check->sctx;
777
	struct btrfs_device *dev;
778 779 780 781 782 783 784 785 786 787 788 789 790 791
	struct btrfs_fs_info *fs_info;
	u64 length;
	u64 logical;
	u64 generation;
	unsigned int failed_mirror_index;
	unsigned int is_metadata;
	unsigned int have_csum;
	u8 *csum;
	struct scrub_block *sblocks_for_recheck; /* holds one for each mirror */
	struct scrub_block *sblock_bad;
	int ret;
	int mirror_index;
	int page_num;
	int success;
792
	static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
793 794 795
				      DEFAULT_RATELIMIT_BURST);

	BUG_ON(sblock_to_check->page_count < 1);
796
	fs_info = sctx->dev_root->fs_info;
797 798 799 800 801 802 803 804 805 806 807
	if (sblock_to_check->pagev[0]->flags & BTRFS_EXTENT_FLAG_SUPER) {
		/*
		 * if we find an error in a super block, we just report it.
		 * They will get written with the next transaction commit
		 * anyway
		 */
		spin_lock(&sctx->stat_lock);
		++sctx->stat.super_errors;
		spin_unlock(&sctx->stat_lock);
		return 0;
	}
808
	length = sblock_to_check->page_count * PAGE_SIZE;
809 810 811 812 813
	logical = sblock_to_check->pagev[0]->logical;
	generation = sblock_to_check->pagev[0]->generation;
	BUG_ON(sblock_to_check->pagev[0]->mirror_num < 1);
	failed_mirror_index = sblock_to_check->pagev[0]->mirror_num - 1;
	is_metadata = !(sblock_to_check->pagev[0]->flags &
814
			BTRFS_EXTENT_FLAG_DATA);
815 816 817
	have_csum = sblock_to_check->pagev[0]->have_csum;
	csum = sblock_to_check->pagev[0]->csum;
	dev = sblock_to_check->pagev[0]->dev;
818

819 820 821 822 823
	if (sctx->is_dev_replace && !is_metadata && !have_csum) {
		sblocks_for_recheck = NULL;
		goto nodatasum_case;
	}

824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856
	/*
	 * read all mirrors one after the other. This includes to
	 * re-read the extent or metadata block that failed (that was
	 * the cause that this fixup code is called) another time,
	 * page by page this time in order to know which pages
	 * caused I/O errors and which ones are good (for all mirrors).
	 * It is the goal to handle the situation when more than one
	 * mirror contains I/O errors, but the errors do not
	 * overlap, i.e. the data can be repaired by selecting the
	 * pages from those mirrors without I/O error on the
	 * particular pages. One example (with blocks >= 2 * PAGE_SIZE)
	 * would be that mirror #1 has an I/O error on the first page,
	 * the second page is good, and mirror #2 has an I/O error on
	 * the second page, but the first page is good.
	 * Then the first page of the first mirror can be repaired by
	 * taking the first page of the second mirror, and the
	 * second page of the second mirror can be repaired by
	 * copying the contents of the 2nd page of the 1st mirror.
	 * One more note: if the pages of one mirror contain I/O
	 * errors, the checksum cannot be verified. In order to get
	 * the best data for repairing, the first attempt is to find
	 * a mirror without I/O errors and with a validated checksum.
	 * Only if this is not possible, the pages are picked from
	 * mirrors with I/O errors without considering the checksum.
	 * If the latter is the case, at the end, the checksum of the
	 * repaired area is verified in order to correctly maintain
	 * the statistics.
	 */

	sblocks_for_recheck = kzalloc(BTRFS_MAX_MIRRORS *
				     sizeof(*sblocks_for_recheck),
				     GFP_NOFS);
	if (!sblocks_for_recheck) {
857 858 859 860 861
		spin_lock(&sctx->stat_lock);
		sctx->stat.malloc_errors++;
		sctx->stat.read_errors++;
		sctx->stat.uncorrectable_errors++;
		spin_unlock(&sctx->stat_lock);
862
		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
863
		goto out;
A
Arne Jansen 已提交
864 865
	}

866
	/* setup the context, map the logical blocks and alloc the pages */
867
	ret = scrub_setup_recheck_block(sctx, fs_info, sblock_to_check, length,
868 869
					logical, sblocks_for_recheck);
	if (ret) {
870 871 872 873
		spin_lock(&sctx->stat_lock);
		sctx->stat.read_errors++;
		sctx->stat.uncorrectable_errors++;
		spin_unlock(&sctx->stat_lock);
874
		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
875 876 877 878
		goto out;
	}
	BUG_ON(failed_mirror_index >= BTRFS_MAX_MIRRORS);
	sblock_bad = sblocks_for_recheck + failed_mirror_index;
879

880
	/* build and submit the bios for the failed mirror, check checksums */
881 882
	scrub_recheck_block(fs_info, sblock_bad, is_metadata, have_csum,
			    csum, generation, sctx->csum_size);
A
Arne Jansen 已提交
883

884 885 886 887 888 889 890 891 892 893
	if (!sblock_bad->header_error && !sblock_bad->checksum_error &&
	    sblock_bad->no_io_error_seen) {
		/*
		 * the error disappeared after reading page by page, or
		 * the area was part of a huge bio and other parts of the
		 * bio caused I/O errors, or the block layer merged several
		 * read requests into one and the error is caused by a
		 * different bio (usually one of the two latter cases is
		 * the cause)
		 */
894 895 896
		spin_lock(&sctx->stat_lock);
		sctx->stat.unverified_errors++;
		spin_unlock(&sctx->stat_lock);
A
Arne Jansen 已提交
897

898 899
		if (sctx->is_dev_replace)
			scrub_write_block_to_dev_replace(sblock_bad);
900
		goto out;
A
Arne Jansen 已提交
901 902
	}

903
	if (!sblock_bad->no_io_error_seen) {
904 905 906
		spin_lock(&sctx->stat_lock);
		sctx->stat.read_errors++;
		spin_unlock(&sctx->stat_lock);
907 908
		if (__ratelimit(&_rs))
			scrub_print_warning("i/o error", sblock_to_check);
909
		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
910
	} else if (sblock_bad->checksum_error) {
911 912 913
		spin_lock(&sctx->stat_lock);
		sctx->stat.csum_errors++;
		spin_unlock(&sctx->stat_lock);
914 915
		if (__ratelimit(&_rs))
			scrub_print_warning("checksum error", sblock_to_check);
916
		btrfs_dev_stat_inc_and_print(dev,
917
					     BTRFS_DEV_STAT_CORRUPTION_ERRS);
918
	} else if (sblock_bad->header_error) {
919 920 921
		spin_lock(&sctx->stat_lock);
		sctx->stat.verify_errors++;
		spin_unlock(&sctx->stat_lock);
922 923 924
		if (__ratelimit(&_rs))
			scrub_print_warning("checksum/header error",
					    sblock_to_check);
925
		if (sblock_bad->generation_error)
926
			btrfs_dev_stat_inc_and_print(dev,
927 928
				BTRFS_DEV_STAT_GENERATION_ERRS);
		else
929
			btrfs_dev_stat_inc_and_print(dev,
930
				BTRFS_DEV_STAT_CORRUPTION_ERRS);
931
	}
A
Arne Jansen 已提交
932

933
	if (sctx->readonly && !sctx->is_dev_replace)
934
		goto did_not_correct_error;
A
Arne Jansen 已提交
935

936 937
	if (!is_metadata && !have_csum) {
		struct scrub_fixup_nodatasum *fixup_nodatasum;
A
Arne Jansen 已提交
938

939 940 941
nodatasum_case:
		WARN_ON(sctx->is_dev_replace);

942 943 944 945 946 947 948 949 950 951
		/*
		 * !is_metadata and !have_csum, this means that the data
		 * might not be COW'ed, that it might be modified
		 * concurrently. The general strategy to work on the
		 * commit root does not help in the case when COW is not
		 * used.
		 */
		fixup_nodatasum = kzalloc(sizeof(*fixup_nodatasum), GFP_NOFS);
		if (!fixup_nodatasum)
			goto did_not_correct_error;
952
		fixup_nodatasum->sctx = sctx;
953
		fixup_nodatasum->dev = dev;
954 955 956
		fixup_nodatasum->logical = logical;
		fixup_nodatasum->root = fs_info->extent_root;
		fixup_nodatasum->mirror_num = failed_mirror_index + 1;
957
		scrub_pending_trans_workers_inc(sctx);
958 959 960 961
		fixup_nodatasum->work.func = scrub_fixup_nodatasum;
		btrfs_queue_worker(&fs_info->scrub_workers,
				   &fixup_nodatasum->work);
		goto out;
A
Arne Jansen 已提交
962 963
	}

964 965
	/*
	 * now build and submit the bios for the other mirrors, check
966 967
	 * checksums.
	 * First try to pick the mirror which is completely without I/O
968 969 970 971 972 973 974 975 976 977 978 979 980 981 982
	 * errors and also does not have a checksum error.
	 * If one is found, and if a checksum is present, the full block
	 * that is known to contain an error is rewritten. Afterwards
	 * the block is known to be corrected.
	 * If a mirror is found which is completely correct, and no
	 * checksum is present, only those pages are rewritten that had
	 * an I/O error in the block to be repaired, since it cannot be
	 * determined, which copy of the other pages is better (and it
	 * could happen otherwise that a correct page would be
	 * overwritten by a bad one).
	 */
	for (mirror_index = 0;
	     mirror_index < BTRFS_MAX_MIRRORS &&
	     sblocks_for_recheck[mirror_index].page_count > 0;
	     mirror_index++) {
983
		struct scrub_block *sblock_other;
984

985 986 987 988 989
		if (mirror_index == failed_mirror_index)
			continue;
		sblock_other = sblocks_for_recheck + mirror_index;

		/* build and submit the bios, check checksums */
990 991 992 993 994
		scrub_recheck_block(fs_info, sblock_other, is_metadata,
				    have_csum, csum, generation,
				    sctx->csum_size);

		if (!sblock_other->header_error &&
995 996
		    !sblock_other->checksum_error &&
		    sblock_other->no_io_error_seen) {
997 998 999 1000 1001 1002 1003 1004 1005
			if (sctx->is_dev_replace) {
				scrub_write_block_to_dev_replace(sblock_other);
			} else {
				int force_write = is_metadata || have_csum;

				ret = scrub_repair_block_from_good_copy(
						sblock_bad, sblock_other,
						force_write);
			}
1006 1007 1008 1009
			if (0 == ret)
				goto corrected_error;
		}
	}
A
Arne Jansen 已提交
1010 1011

	/*
1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069
	 * for dev_replace, pick good pages and write to the target device.
	 */
	if (sctx->is_dev_replace) {
		success = 1;
		for (page_num = 0; page_num < sblock_bad->page_count;
		     page_num++) {
			int sub_success;

			sub_success = 0;
			for (mirror_index = 0;
			     mirror_index < BTRFS_MAX_MIRRORS &&
			     sblocks_for_recheck[mirror_index].page_count > 0;
			     mirror_index++) {
				struct scrub_block *sblock_other =
					sblocks_for_recheck + mirror_index;
				struct scrub_page *page_other =
					sblock_other->pagev[page_num];

				if (!page_other->io_error) {
					ret = scrub_write_page_to_dev_replace(
							sblock_other, page_num);
					if (ret == 0) {
						/* succeeded for this page */
						sub_success = 1;
						break;
					} else {
						btrfs_dev_replace_stats_inc(
							&sctx->dev_root->
							fs_info->dev_replace.
							num_write_errors);
					}
				}
			}

			if (!sub_success) {
				/*
				 * did not find a mirror to fetch the page
				 * from. scrub_write_page_to_dev_replace()
				 * handles this case (page->io_error), by
				 * filling the block with zeros before
				 * submitting the write request
				 */
				success = 0;
				ret = scrub_write_page_to_dev_replace(
						sblock_bad, page_num);
				if (ret)
					btrfs_dev_replace_stats_inc(
						&sctx->dev_root->fs_info->
						dev_replace.num_write_errors);
			}
		}

		goto out;
	}

	/*
	 * for regular scrub, repair those pages that are errored.
	 * In case of I/O errors in the area that is supposed to be
1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090
	 * repaired, continue by picking good copies of those pages.
	 * Select the good pages from mirrors to rewrite bad pages from
	 * the area to fix. Afterwards verify the checksum of the block
	 * that is supposed to be repaired. This verification step is
	 * only done for the purpose of statistic counting and for the
	 * final scrub report, whether errors remain.
	 * A perfect algorithm could make use of the checksum and try
	 * all possible combinations of pages from the different mirrors
	 * until the checksum verification succeeds. For example, when
	 * the 2nd page of mirror #1 faces I/O errors, and the 2nd page
	 * of mirror #2 is readable but the final checksum test fails,
	 * then the 2nd page of mirror #3 could be tried, whether now
	 * the final checksum succeedes. But this would be a rare
	 * exception and is therefore not implemented. At least it is
	 * avoided that the good copy is overwritten.
	 * A more useful improvement would be to pick the sectors
	 * without I/O error based on sector sizes (512 bytes on legacy
	 * disks) instead of on PAGE_SIZE. Then maybe 512 byte of one
	 * mirror could be repaired by taking 512 byte of a different
	 * mirror, even if other 512 byte sectors in the same PAGE_SIZE
	 * area are unreadable.
A
Arne Jansen 已提交
1091 1092
	 */

1093 1094 1095 1096 1097 1098
	/* can only fix I/O errors from here on */
	if (sblock_bad->no_io_error_seen)
		goto did_not_correct_error;

	success = 1;
	for (page_num = 0; page_num < sblock_bad->page_count; page_num++) {
1099
		struct scrub_page *page_bad = sblock_bad->pagev[page_num];
1100 1101

		if (!page_bad->io_error)
A
Arne Jansen 已提交
1102
			continue;
1103 1104 1105 1106 1107 1108 1109

		for (mirror_index = 0;
		     mirror_index < BTRFS_MAX_MIRRORS &&
		     sblocks_for_recheck[mirror_index].page_count > 0;
		     mirror_index++) {
			struct scrub_block *sblock_other = sblocks_for_recheck +
							   mirror_index;
1110 1111
			struct scrub_page *page_other = sblock_other->pagev[
							page_num];
1112 1113 1114 1115 1116 1117 1118 1119 1120

			if (!page_other->io_error) {
				ret = scrub_repair_page_from_good_copy(
					sblock_bad, sblock_other, page_num, 0);
				if (0 == ret) {
					page_bad->io_error = 0;
					break; /* succeeded for this page */
				}
			}
I
Ilya Dryomov 已提交
1121
		}
A
Arne Jansen 已提交
1122

1123 1124 1125 1126
		if (page_bad->io_error) {
			/* did not find a mirror to copy the page from */
			success = 0;
		}
A
Arne Jansen 已提交
1127 1128
	}

1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139
	if (success) {
		if (is_metadata || have_csum) {
			/*
			 * need to verify the checksum now that all
			 * sectors on disk are repaired (the write
			 * request for data to be repaired is on its way).
			 * Just be lazy and use scrub_recheck_block()
			 * which re-reads the data before the checksum
			 * is verified, but most likely the data comes out
			 * of the page cache.
			 */
1140 1141 1142 1143
			scrub_recheck_block(fs_info, sblock_bad,
					    is_metadata, have_csum, csum,
					    generation, sctx->csum_size);
			if (!sblock_bad->header_error &&
1144 1145 1146 1147 1148 1149 1150
			    !sblock_bad->checksum_error &&
			    sblock_bad->no_io_error_seen)
				goto corrected_error;
			else
				goto did_not_correct_error;
		} else {
corrected_error:
1151 1152 1153
			spin_lock(&sctx->stat_lock);
			sctx->stat.corrected_errors++;
			spin_unlock(&sctx->stat_lock);
1154
			printk_ratelimited_in_rcu(KERN_ERR
1155
				"btrfs: fixed up error at logical %llu on dev %s\n",
1156
				logical, rcu_str_deref(dev->name));
A
Arne Jansen 已提交
1157
		}
1158 1159
	} else {
did_not_correct_error:
1160 1161 1162
		spin_lock(&sctx->stat_lock);
		sctx->stat.uncorrectable_errors++;
		spin_unlock(&sctx->stat_lock);
1163
		printk_ratelimited_in_rcu(KERN_ERR
1164
			"btrfs: unable to fixup (regular) error at logical %llu on dev %s\n",
1165
			logical, rcu_str_deref(dev->name));
I
Ilya Dryomov 已提交
1166
	}
A
Arne Jansen 已提交
1167

1168 1169 1170 1171 1172 1173 1174 1175
out:
	if (sblocks_for_recheck) {
		for (mirror_index = 0; mirror_index < BTRFS_MAX_MIRRORS;
		     mirror_index++) {
			struct scrub_block *sblock = sblocks_for_recheck +
						     mirror_index;
			int page_index;

1176 1177 1178 1179 1180
			for (page_index = 0; page_index < sblock->page_count;
			     page_index++) {
				sblock->pagev[page_index]->sblock = NULL;
				scrub_page_put(sblock->pagev[page_index]);
			}
1181 1182 1183
		}
		kfree(sblocks_for_recheck);
	}
A
Arne Jansen 已提交
1184

1185 1186
	return 0;
}
A
Arne Jansen 已提交
1187

1188
static int scrub_setup_recheck_block(struct scrub_ctx *sctx,
1189
				     struct btrfs_fs_info *fs_info,
1190
				     struct scrub_block *original_sblock,
1191 1192 1193 1194 1195 1196 1197 1198
				     u64 length, u64 logical,
				     struct scrub_block *sblocks_for_recheck)
{
	int page_index;
	int mirror_index;
	int ret;

	/*
1199
	 * note: the two members ref_count and outstanding_pages
1200 1201 1202 1203 1204 1205 1206 1207 1208
	 * are not used (and not set) in the blocks that are used for
	 * the recheck procedure
	 */

	page_index = 0;
	while (length > 0) {
		u64 sublen = min_t(u64, length, PAGE_SIZE);
		u64 mapped_length = sublen;
		struct btrfs_bio *bbio = NULL;
A
Arne Jansen 已提交
1209

1210 1211 1212 1213
		/*
		 * with a length of PAGE_SIZE, each returned stripe
		 * represents one mirror
		 */
1214 1215
		ret = btrfs_map_block(fs_info, REQ_GET_READ_MIRRORS, logical,
				      &mapped_length, &bbio, 0);
1216 1217 1218 1219
		if (ret || !bbio || mapped_length < sublen) {
			kfree(bbio);
			return -EIO;
		}
A
Arne Jansen 已提交
1220

1221
		BUG_ON(page_index >= SCRUB_PAGES_PER_RD_BIO);
1222 1223 1224 1225 1226 1227 1228 1229 1230
		for (mirror_index = 0; mirror_index < (int)bbio->num_stripes;
		     mirror_index++) {
			struct scrub_block *sblock;
			struct scrub_page *page;

			if (mirror_index >= BTRFS_MAX_MIRRORS)
				continue;

			sblock = sblocks_for_recheck + mirror_index;
1231 1232 1233 1234
			sblock->sctx = sctx;
			page = kzalloc(sizeof(*page), GFP_NOFS);
			if (!page) {
leave_nomem:
1235 1236 1237
				spin_lock(&sctx->stat_lock);
				sctx->stat.malloc_errors++;
				spin_unlock(&sctx->stat_lock);
1238
				kfree(bbio);
1239 1240
				return -ENOMEM;
			}
1241 1242 1243 1244
			scrub_page_get(page);
			sblock->pagev[page_index] = page;
			page->logical = logical;
			page->physical = bbio->stripes[mirror_index].physical;
1245 1246 1247 1248
			BUG_ON(page_index >= original_sblock->page_count);
			page->physical_for_dev_replace =
				original_sblock->pagev[page_index]->
				physical_for_dev_replace;
1249 1250 1251
			/* for missing devices, dev->bdev is NULL */
			page->dev = bbio->stripes[mirror_index].dev;
			page->mirror_num = mirror_index + 1;
1252
			sblock->page_count++;
1253 1254 1255
			page->page = alloc_page(GFP_NOFS);
			if (!page->page)
				goto leave_nomem;
1256 1257 1258 1259 1260 1261 1262 1263
		}
		kfree(bbio);
		length -= sublen;
		logical += sublen;
		page_index++;
	}

	return 0;
I
Ilya Dryomov 已提交
1264 1265
}

1266 1267 1268 1269 1270 1271 1272
/*
 * this function will check the on disk data for checksum errors, header
 * errors and read I/O errors. If any I/O errors happen, the exact pages
 * which are errored are marked as being bad. The goal is to enable scrub
 * to take those pages that are not errored from all the mirrors so that
 * the pages that are errored in the just handled mirror can be repaired.
 */
1273 1274 1275 1276
static void scrub_recheck_block(struct btrfs_fs_info *fs_info,
				struct scrub_block *sblock, int is_metadata,
				int have_csum, u8 *csum, u64 generation,
				u16 csum_size)
I
Ilya Dryomov 已提交
1277
{
1278
	int page_num;
I
Ilya Dryomov 已提交
1279

1280 1281 1282
	sblock->no_io_error_seen = 1;
	sblock->header_error = 0;
	sblock->checksum_error = 0;
I
Ilya Dryomov 已提交
1283

1284 1285
	for (page_num = 0; page_num < sblock->page_count; page_num++) {
		struct bio *bio;
1286
		struct scrub_page *page = sblock->pagev[page_num];
1287 1288
		DECLARE_COMPLETION_ONSTACK(complete);

1289
		if (page->dev->bdev == NULL) {
1290 1291 1292 1293 1294
			page->io_error = 1;
			sblock->no_io_error_seen = 0;
			continue;
		}

1295
		WARN_ON(!page->page);
1296
		bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
1297 1298 1299 1300 1301
		if (!bio) {
			page->io_error = 1;
			sblock->no_io_error_seen = 0;
			continue;
		}
1302
		bio->bi_bdev = page->dev->bdev;
1303 1304 1305 1306
		bio->bi_sector = page->physical >> 9;
		bio->bi_end_io = scrub_complete_bio_end_io;
		bio->bi_private = &complete;

1307
		bio_add_page(bio, page->page, PAGE_SIZE, 0);
1308
		btrfsic_submit_bio(READ, bio);
I
Ilya Dryomov 已提交
1309

1310 1311
		/* this will also unplug the queue */
		wait_for_completion(&complete);
I
Ilya Dryomov 已提交
1312

1313 1314 1315 1316 1317
		page->io_error = !test_bit(BIO_UPTODATE, &bio->bi_flags);
		if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
			sblock->no_io_error_seen = 0;
		bio_put(bio);
	}
I
Ilya Dryomov 已提交
1318

1319 1320 1321 1322 1323
	if (sblock->no_io_error_seen)
		scrub_recheck_block_checksum(fs_info, sblock, is_metadata,
					     have_csum, csum, generation,
					     csum_size);

1324
	return;
A
Arne Jansen 已提交
1325 1326
}

1327 1328 1329 1330 1331
static void scrub_recheck_block_checksum(struct btrfs_fs_info *fs_info,
					 struct scrub_block *sblock,
					 int is_metadata, int have_csum,
					 const u8 *csum, u64 generation,
					 u16 csum_size)
A
Arne Jansen 已提交
1332
{
1333 1334 1335 1336 1337
	int page_num;
	u8 calculated_csum[BTRFS_CSUM_SIZE];
	u32 crc = ~(u32)0;
	void *mapped_buffer;

1338
	WARN_ON(!sblock->pagev[0]->page);
1339 1340 1341
	if (is_metadata) {
		struct btrfs_header *h;

1342
		mapped_buffer = kmap_atomic(sblock->pagev[0]->page);
1343 1344
		h = (struct btrfs_header *)mapped_buffer;

1345
		if (sblock->pagev[0]->logical != btrfs_stack_header_bytenr(h) ||
1346 1347
		    memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE) ||
		    memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
1348
			   BTRFS_UUID_SIZE)) {
1349
			sblock->header_error = 1;
1350
		} else if (generation != btrfs_stack_header_generation(h)) {
1351 1352 1353
			sblock->header_error = 1;
			sblock->generation_error = 1;
		}
1354 1355 1356 1357
		csum = h->csum;
	} else {
		if (!have_csum)
			return;
A
Arne Jansen 已提交
1358

1359
		mapped_buffer = kmap_atomic(sblock->pagev[0]->page);
1360
	}
A
Arne Jansen 已提交
1361

1362 1363
	for (page_num = 0;;) {
		if (page_num == 0 && is_metadata)
1364
			crc = btrfs_csum_data(
1365 1366 1367
				((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE,
				crc, PAGE_SIZE - BTRFS_CSUM_SIZE);
		else
1368
			crc = btrfs_csum_data(mapped_buffer, crc, PAGE_SIZE);
1369

1370
		kunmap_atomic(mapped_buffer);
1371 1372 1373
		page_num++;
		if (page_num >= sblock->page_count)
			break;
1374
		WARN_ON(!sblock->pagev[page_num]->page);
1375

1376
		mapped_buffer = kmap_atomic(sblock->pagev[page_num]->page);
1377 1378 1379 1380 1381
	}

	btrfs_csum_final(crc, calculated_csum);
	if (memcmp(calculated_csum, csum, csum_size))
		sblock->checksum_error = 1;
A
Arne Jansen 已提交
1382 1383
}

1384
static void scrub_complete_bio_end_io(struct bio *bio, int err)
A
Arne Jansen 已提交
1385
{
1386 1387
	complete((struct completion *)bio->bi_private);
}
A
Arne Jansen 已提交
1388

1389 1390 1391 1392 1393 1394
static int scrub_repair_block_from_good_copy(struct scrub_block *sblock_bad,
					     struct scrub_block *sblock_good,
					     int force_write)
{
	int page_num;
	int ret = 0;
I
Ilya Dryomov 已提交
1395

1396 1397
	for (page_num = 0; page_num < sblock_bad->page_count; page_num++) {
		int ret_sub;
I
Ilya Dryomov 已提交
1398

1399 1400 1401 1402 1403 1404
		ret_sub = scrub_repair_page_from_good_copy(sblock_bad,
							   sblock_good,
							   page_num,
							   force_write);
		if (ret_sub)
			ret = ret_sub;
A
Arne Jansen 已提交
1405
	}
1406 1407 1408 1409 1410 1411 1412 1413

	return ret;
}

static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
					    struct scrub_block *sblock_good,
					    int page_num, int force_write)
{
1414 1415
	struct scrub_page *page_bad = sblock_bad->pagev[page_num];
	struct scrub_page *page_good = sblock_good->pagev[page_num];
1416

1417 1418
	BUG_ON(page_bad->page == NULL);
	BUG_ON(page_good->page == NULL);
1419 1420 1421 1422 1423 1424
	if (force_write || sblock_bad->header_error ||
	    sblock_bad->checksum_error || page_bad->io_error) {
		struct bio *bio;
		int ret;
		DECLARE_COMPLETION_ONSTACK(complete);

1425 1426 1427 1428 1429 1430
		if (!page_bad->dev->bdev) {
			printk_ratelimited(KERN_WARNING
				"btrfs: scrub_repair_page_from_good_copy(bdev == NULL) is unexpected!\n");
			return -EIO;
		}

1431
		bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
1432 1433
		if (!bio)
			return -EIO;
1434
		bio->bi_bdev = page_bad->dev->bdev;
1435 1436 1437 1438 1439 1440 1441 1442
		bio->bi_sector = page_bad->physical >> 9;
		bio->bi_end_io = scrub_complete_bio_end_io;
		bio->bi_private = &complete;

		ret = bio_add_page(bio, page_good->page, PAGE_SIZE, 0);
		if (PAGE_SIZE != ret) {
			bio_put(bio);
			return -EIO;
1443
		}
1444 1445 1446 1447
		btrfsic_submit_bio(WRITE, bio);

		/* this will also unplug the queue */
		wait_for_completion(&complete);
1448 1449 1450
		if (!bio_flagged(bio, BIO_UPTODATE)) {
			btrfs_dev_stat_inc_and_print(page_bad->dev,
				BTRFS_DEV_STAT_WRITE_ERRS);
1451 1452 1453
			btrfs_dev_replace_stats_inc(
				&sblock_bad->sctx->dev_root->fs_info->
				dev_replace.num_write_errors);
1454 1455 1456
			bio_put(bio);
			return -EIO;
		}
1457
		bio_put(bio);
A
Arne Jansen 已提交
1458 1459
	}

1460 1461 1462
	return 0;
}

1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521
static void scrub_write_block_to_dev_replace(struct scrub_block *sblock)
{
	int page_num;

	for (page_num = 0; page_num < sblock->page_count; page_num++) {
		int ret;

		ret = scrub_write_page_to_dev_replace(sblock, page_num);
		if (ret)
			btrfs_dev_replace_stats_inc(
				&sblock->sctx->dev_root->fs_info->dev_replace.
				num_write_errors);
	}
}

static int scrub_write_page_to_dev_replace(struct scrub_block *sblock,
					   int page_num)
{
	struct scrub_page *spage = sblock->pagev[page_num];

	BUG_ON(spage->page == NULL);
	if (spage->io_error) {
		void *mapped_buffer = kmap_atomic(spage->page);

		memset(mapped_buffer, 0, PAGE_CACHE_SIZE);
		flush_dcache_page(spage->page);
		kunmap_atomic(mapped_buffer);
	}
	return scrub_add_page_to_wr_bio(sblock->sctx, spage);
}

static int scrub_add_page_to_wr_bio(struct scrub_ctx *sctx,
				    struct scrub_page *spage)
{
	struct scrub_wr_ctx *wr_ctx = &sctx->wr_ctx;
	struct scrub_bio *sbio;
	int ret;

	mutex_lock(&wr_ctx->wr_lock);
again:
	if (!wr_ctx->wr_curr_bio) {
		wr_ctx->wr_curr_bio = kzalloc(sizeof(*wr_ctx->wr_curr_bio),
					      GFP_NOFS);
		if (!wr_ctx->wr_curr_bio) {
			mutex_unlock(&wr_ctx->wr_lock);
			return -ENOMEM;
		}
		wr_ctx->wr_curr_bio->sctx = sctx;
		wr_ctx->wr_curr_bio->page_count = 0;
	}
	sbio = wr_ctx->wr_curr_bio;
	if (sbio->page_count == 0) {
		struct bio *bio;

		sbio->physical = spage->physical_for_dev_replace;
		sbio->logical = spage->logical;
		sbio->dev = wr_ctx->tgtdev;
		bio = sbio->bio;
		if (!bio) {
1522
			bio = btrfs_io_bio_alloc(GFP_NOFS, wr_ctx->pages_per_wr_bio);
1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624
			if (!bio) {
				mutex_unlock(&wr_ctx->wr_lock);
				return -ENOMEM;
			}
			sbio->bio = bio;
		}

		bio->bi_private = sbio;
		bio->bi_end_io = scrub_wr_bio_end_io;
		bio->bi_bdev = sbio->dev->bdev;
		bio->bi_sector = sbio->physical >> 9;
		sbio->err = 0;
	} else if (sbio->physical + sbio->page_count * PAGE_SIZE !=
		   spage->physical_for_dev_replace ||
		   sbio->logical + sbio->page_count * PAGE_SIZE !=
		   spage->logical) {
		scrub_wr_submit(sctx);
		goto again;
	}

	ret = bio_add_page(sbio->bio, spage->page, PAGE_SIZE, 0);
	if (ret != PAGE_SIZE) {
		if (sbio->page_count < 1) {
			bio_put(sbio->bio);
			sbio->bio = NULL;
			mutex_unlock(&wr_ctx->wr_lock);
			return -EIO;
		}
		scrub_wr_submit(sctx);
		goto again;
	}

	sbio->pagev[sbio->page_count] = spage;
	scrub_page_get(spage);
	sbio->page_count++;
	if (sbio->page_count == wr_ctx->pages_per_wr_bio)
		scrub_wr_submit(sctx);
	mutex_unlock(&wr_ctx->wr_lock);

	return 0;
}

static void scrub_wr_submit(struct scrub_ctx *sctx)
{
	struct scrub_wr_ctx *wr_ctx = &sctx->wr_ctx;
	struct scrub_bio *sbio;

	if (!wr_ctx->wr_curr_bio)
		return;

	sbio = wr_ctx->wr_curr_bio;
	wr_ctx->wr_curr_bio = NULL;
	WARN_ON(!sbio->bio->bi_bdev);
	scrub_pending_bio_inc(sctx);
	/* process all writes in a single worker thread. Then the block layer
	 * orders the requests before sending them to the driver which
	 * doubled the write performance on spinning disks when measured
	 * with Linux 3.5 */
	btrfsic_submit_bio(WRITE, sbio->bio);
}

static void scrub_wr_bio_end_io(struct bio *bio, int err)
{
	struct scrub_bio *sbio = bio->bi_private;
	struct btrfs_fs_info *fs_info = sbio->dev->dev_root->fs_info;

	sbio->err = err;
	sbio->bio = bio;

	sbio->work.func = scrub_wr_bio_end_io_worker;
	btrfs_queue_worker(&fs_info->scrub_wr_completion_workers, &sbio->work);
}

static void scrub_wr_bio_end_io_worker(struct btrfs_work *work)
{
	struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
	struct scrub_ctx *sctx = sbio->sctx;
	int i;

	WARN_ON(sbio->page_count > SCRUB_PAGES_PER_WR_BIO);
	if (sbio->err) {
		struct btrfs_dev_replace *dev_replace =
			&sbio->sctx->dev_root->fs_info->dev_replace;

		for (i = 0; i < sbio->page_count; i++) {
			struct scrub_page *spage = sbio->pagev[i];

			spage->io_error = 1;
			btrfs_dev_replace_stats_inc(&dev_replace->
						    num_write_errors);
		}
	}

	for (i = 0; i < sbio->page_count; i++)
		scrub_page_put(sbio->pagev[i]);

	bio_put(sbio->bio);
	kfree(sbio);
	scrub_pending_bio_dec(sctx);
}

static int scrub_checksum(struct scrub_block *sblock)
1625 1626 1627 1628
{
	u64 flags;
	int ret;

1629 1630
	WARN_ON(sblock->page_count < 1);
	flags = sblock->pagev[0]->flags;
1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641
	ret = 0;
	if (flags & BTRFS_EXTENT_FLAG_DATA)
		ret = scrub_checksum_data(sblock);
	else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)
		ret = scrub_checksum_tree_block(sblock);
	else if (flags & BTRFS_EXTENT_FLAG_SUPER)
		(void)scrub_checksum_super(sblock);
	else
		WARN_ON(1);
	if (ret)
		scrub_handle_errored_block(sblock);
1642 1643

	return ret;
A
Arne Jansen 已提交
1644 1645
}

1646
static int scrub_checksum_data(struct scrub_block *sblock)
A
Arne Jansen 已提交
1647
{
1648
	struct scrub_ctx *sctx = sblock->sctx;
A
Arne Jansen 已提交
1649
	u8 csum[BTRFS_CSUM_SIZE];
1650 1651 1652
	u8 *on_disk_csum;
	struct page *page;
	void *buffer;
A
Arne Jansen 已提交
1653 1654
	u32 crc = ~(u32)0;
	int fail = 0;
1655 1656
	u64 len;
	int index;
A
Arne Jansen 已提交
1657

1658
	BUG_ON(sblock->page_count < 1);
1659
	if (!sblock->pagev[0]->have_csum)
A
Arne Jansen 已提交
1660 1661
		return 0;

1662 1663
	on_disk_csum = sblock->pagev[0]->csum;
	page = sblock->pagev[0]->page;
1664
	buffer = kmap_atomic(page);
1665

1666
	len = sctx->sectorsize;
1667 1668 1669 1670
	index = 0;
	for (;;) {
		u64 l = min_t(u64, len, PAGE_SIZE);

1671
		crc = btrfs_csum_data(buffer, crc, l);
1672
		kunmap_atomic(buffer);
1673 1674 1675 1676 1677
		len -= l;
		if (len == 0)
			break;
		index++;
		BUG_ON(index >= sblock->page_count);
1678 1679
		BUG_ON(!sblock->pagev[index]->page);
		page = sblock->pagev[index]->page;
1680
		buffer = kmap_atomic(page);
1681 1682
	}

A
Arne Jansen 已提交
1683
	btrfs_csum_final(crc, csum);
1684
	if (memcmp(csum, on_disk_csum, sctx->csum_size))
A
Arne Jansen 已提交
1685 1686 1687 1688 1689
		fail = 1;

	return fail;
}

1690
static int scrub_checksum_tree_block(struct scrub_block *sblock)
A
Arne Jansen 已提交
1691
{
1692
	struct scrub_ctx *sctx = sblock->sctx;
A
Arne Jansen 已提交
1693
	struct btrfs_header *h;
1694
	struct btrfs_root *root = sctx->dev_root;
A
Arne Jansen 已提交
1695
	struct btrfs_fs_info *fs_info = root->fs_info;
1696 1697 1698 1699 1700 1701
	u8 calculated_csum[BTRFS_CSUM_SIZE];
	u8 on_disk_csum[BTRFS_CSUM_SIZE];
	struct page *page;
	void *mapped_buffer;
	u64 mapped_size;
	void *p;
A
Arne Jansen 已提交
1702 1703 1704
	u32 crc = ~(u32)0;
	int fail = 0;
	int crc_fail = 0;
1705 1706 1707 1708
	u64 len;
	int index;

	BUG_ON(sblock->page_count < 1);
1709
	page = sblock->pagev[0]->page;
1710
	mapped_buffer = kmap_atomic(page);
1711
	h = (struct btrfs_header *)mapped_buffer;
1712
	memcpy(on_disk_csum, h->csum, sctx->csum_size);
A
Arne Jansen 已提交
1713 1714 1715 1716 1717 1718 1719

	/*
	 * we don't use the getter functions here, as we
	 * a) don't have an extent buffer and
	 * b) the page is already kmapped
	 */

1720
	if (sblock->pagev[0]->logical != btrfs_stack_header_bytenr(h))
A
Arne Jansen 已提交
1721 1722
		++fail;

1723
	if (sblock->pagev[0]->generation != btrfs_stack_header_generation(h))
A
Arne Jansen 已提交
1724 1725 1726 1727 1728 1729 1730 1731 1732
		++fail;

	if (memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
		++fail;

	if (memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
		   BTRFS_UUID_SIZE))
		++fail;

1733
	WARN_ON(sctx->nodesize != sctx->leafsize);
1734
	len = sctx->nodesize - BTRFS_CSUM_SIZE;
1735 1736 1737 1738 1739 1740
	mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE;
	p = ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE;
	index = 0;
	for (;;) {
		u64 l = min_t(u64, len, mapped_size);

1741
		crc = btrfs_csum_data(p, crc, l);
1742
		kunmap_atomic(mapped_buffer);
1743 1744 1745 1746 1747
		len -= l;
		if (len == 0)
			break;
		index++;
		BUG_ON(index >= sblock->page_count);
1748 1749
		BUG_ON(!sblock->pagev[index]->page);
		page = sblock->pagev[index]->page;
1750
		mapped_buffer = kmap_atomic(page);
1751 1752 1753 1754 1755
		mapped_size = PAGE_SIZE;
		p = mapped_buffer;
	}

	btrfs_csum_final(crc, calculated_csum);
1756
	if (memcmp(calculated_csum, on_disk_csum, sctx->csum_size))
A
Arne Jansen 已提交
1757 1758 1759 1760 1761
		++crc_fail;

	return fail || crc_fail;
}

1762
static int scrub_checksum_super(struct scrub_block *sblock)
A
Arne Jansen 已提交
1763 1764
{
	struct btrfs_super_block *s;
1765
	struct scrub_ctx *sctx = sblock->sctx;
1766
	struct btrfs_root *root = sctx->dev_root;
A
Arne Jansen 已提交
1767
	struct btrfs_fs_info *fs_info = root->fs_info;
1768 1769 1770 1771 1772 1773
	u8 calculated_csum[BTRFS_CSUM_SIZE];
	u8 on_disk_csum[BTRFS_CSUM_SIZE];
	struct page *page;
	void *mapped_buffer;
	u64 mapped_size;
	void *p;
A
Arne Jansen 已提交
1774
	u32 crc = ~(u32)0;
1775 1776
	int fail_gen = 0;
	int fail_cor = 0;
1777 1778
	u64 len;
	int index;
A
Arne Jansen 已提交
1779

1780
	BUG_ON(sblock->page_count < 1);
1781
	page = sblock->pagev[0]->page;
1782
	mapped_buffer = kmap_atomic(page);
1783
	s = (struct btrfs_super_block *)mapped_buffer;
1784
	memcpy(on_disk_csum, s->csum, sctx->csum_size);
A
Arne Jansen 已提交
1785

1786
	if (sblock->pagev[0]->logical != btrfs_super_bytenr(s))
1787
		++fail_cor;
A
Arne Jansen 已提交
1788

1789
	if (sblock->pagev[0]->generation != btrfs_super_generation(s))
1790
		++fail_gen;
A
Arne Jansen 已提交
1791 1792

	if (memcmp(s->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
1793
		++fail_cor;
A
Arne Jansen 已提交
1794

1795 1796 1797 1798 1799 1800 1801
	len = BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE;
	mapped_size = PAGE_SIZE - BTRFS_CSUM_SIZE;
	p = ((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE;
	index = 0;
	for (;;) {
		u64 l = min_t(u64, len, mapped_size);

1802
		crc = btrfs_csum_data(p, crc, l);
1803
		kunmap_atomic(mapped_buffer);
1804 1805 1806 1807 1808
		len -= l;
		if (len == 0)
			break;
		index++;
		BUG_ON(index >= sblock->page_count);
1809 1810
		BUG_ON(!sblock->pagev[index]->page);
		page = sblock->pagev[index]->page;
1811
		mapped_buffer = kmap_atomic(page);
1812 1813 1814 1815 1816
		mapped_size = PAGE_SIZE;
		p = mapped_buffer;
	}

	btrfs_csum_final(crc, calculated_csum);
1817
	if (memcmp(calculated_csum, on_disk_csum, sctx->csum_size))
1818
		++fail_cor;
A
Arne Jansen 已提交
1819

1820
	if (fail_cor + fail_gen) {
A
Arne Jansen 已提交
1821 1822 1823 1824 1825
		/*
		 * if we find an error in a super block, we just report it.
		 * They will get written with the next transaction commit
		 * anyway
		 */
1826 1827 1828
		spin_lock(&sctx->stat_lock);
		++sctx->stat.super_errors;
		spin_unlock(&sctx->stat_lock);
1829
		if (fail_cor)
1830
			btrfs_dev_stat_inc_and_print(sblock->pagev[0]->dev,
1831 1832
				BTRFS_DEV_STAT_CORRUPTION_ERRS);
		else
1833
			btrfs_dev_stat_inc_and_print(sblock->pagev[0]->dev,
1834
				BTRFS_DEV_STAT_GENERATION_ERRS);
A
Arne Jansen 已提交
1835 1836
	}

1837
	return fail_cor + fail_gen;
A
Arne Jansen 已提交
1838 1839
}

1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850
static void scrub_block_get(struct scrub_block *sblock)
{
	atomic_inc(&sblock->ref_count);
}

static void scrub_block_put(struct scrub_block *sblock)
{
	if (atomic_dec_and_test(&sblock->ref_count)) {
		int i;

		for (i = 0; i < sblock->page_count; i++)
1851
			scrub_page_put(sblock->pagev[i]);
1852 1853 1854 1855
		kfree(sblock);
	}
}

1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869
static void scrub_page_get(struct scrub_page *spage)
{
	atomic_inc(&spage->ref_count);
}

static void scrub_page_put(struct scrub_page *spage)
{
	if (atomic_dec_and_test(&spage->ref_count)) {
		if (spage->page)
			__free_page(spage->page);
		kfree(spage);
	}
}

1870
static void scrub_submit(struct scrub_ctx *sctx)
A
Arne Jansen 已提交
1871 1872 1873
{
	struct scrub_bio *sbio;

1874
	if (sctx->curr == -1)
S
Stefan Behrens 已提交
1875
		return;
A
Arne Jansen 已提交
1876

1877 1878
	sbio = sctx->bios[sctx->curr];
	sctx->curr = -1;
1879
	scrub_pending_bio_inc(sctx);
A
Arne Jansen 已提交
1880

1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894
	if (!sbio->bio->bi_bdev) {
		/*
		 * this case should not happen. If btrfs_map_block() is
		 * wrong, it could happen for dev-replace operations on
		 * missing devices when no mirrors are available, but in
		 * this case it should already fail the mount.
		 * This case is handled correctly (but _very_ slowly).
		 */
		printk_ratelimited(KERN_WARNING
			"btrfs: scrub_submit(bio bdev == NULL) is unexpected!\n");
		bio_endio(sbio->bio, -EIO);
	} else {
		btrfsic_submit_bio(READ, sbio->bio);
	}
A
Arne Jansen 已提交
1895 1896
}

1897 1898
static int scrub_add_page_to_rd_bio(struct scrub_ctx *sctx,
				    struct scrub_page *spage)
A
Arne Jansen 已提交
1899
{
1900
	struct scrub_block *sblock = spage->sblock;
A
Arne Jansen 已提交
1901
	struct scrub_bio *sbio;
1902
	int ret;
A
Arne Jansen 已提交
1903 1904 1905 1906 1907

again:
	/*
	 * grab a fresh bio or wait for one to become available
	 */
1908 1909 1910 1911 1912 1913 1914 1915
	while (sctx->curr == -1) {
		spin_lock(&sctx->list_lock);
		sctx->curr = sctx->first_free;
		if (sctx->curr != -1) {
			sctx->first_free = sctx->bios[sctx->curr]->next_free;
			sctx->bios[sctx->curr]->next_free = -1;
			sctx->bios[sctx->curr]->page_count = 0;
			spin_unlock(&sctx->list_lock);
A
Arne Jansen 已提交
1916
		} else {
1917 1918
			spin_unlock(&sctx->list_lock);
			wait_event(sctx->list_wait, sctx->first_free != -1);
A
Arne Jansen 已提交
1919 1920
		}
	}
1921
	sbio = sctx->bios[sctx->curr];
1922
	if (sbio->page_count == 0) {
1923 1924
		struct bio *bio;

1925 1926
		sbio->physical = spage->physical;
		sbio->logical = spage->logical;
1927
		sbio->dev = spage->dev;
1928 1929
		bio = sbio->bio;
		if (!bio) {
1930
			bio = btrfs_io_bio_alloc(GFP_NOFS, sctx->pages_per_rd_bio);
1931 1932 1933 1934
			if (!bio)
				return -ENOMEM;
			sbio->bio = bio;
		}
1935 1936 1937

		bio->bi_private = sbio;
		bio->bi_end_io = scrub_bio_end_io;
1938 1939
		bio->bi_bdev = sbio->dev->bdev;
		bio->bi_sector = sbio->physical >> 9;
1940
		sbio->err = 0;
1941 1942 1943
	} else if (sbio->physical + sbio->page_count * PAGE_SIZE !=
		   spage->physical ||
		   sbio->logical + sbio->page_count * PAGE_SIZE !=
1944 1945
		   spage->logical ||
		   sbio->dev != spage->dev) {
1946
		scrub_submit(sctx);
A
Arne Jansen 已提交
1947 1948
		goto again;
	}
1949

1950 1951 1952 1953 1954 1955 1956 1957
	sbio->pagev[sbio->page_count] = spage;
	ret = bio_add_page(sbio->bio, spage->page, PAGE_SIZE, 0);
	if (ret != PAGE_SIZE) {
		if (sbio->page_count < 1) {
			bio_put(sbio->bio);
			sbio->bio = NULL;
			return -EIO;
		}
1958
		scrub_submit(sctx);
1959 1960 1961
		goto again;
	}

1962
	scrub_block_get(sblock); /* one for the page added to the bio */
1963 1964
	atomic_inc(&sblock->outstanding_pages);
	sbio->page_count++;
1965
	if (sbio->page_count == sctx->pages_per_rd_bio)
1966
		scrub_submit(sctx);
1967 1968 1969 1970

	return 0;
}

1971
static int scrub_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
1972
		       u64 physical, struct btrfs_device *dev, u64 flags,
1973 1974
		       u64 gen, int mirror_num, u8 *csum, int force,
		       u64 physical_for_dev_replace)
1975 1976 1977 1978 1979 1980
{
	struct scrub_block *sblock;
	int index;

	sblock = kzalloc(sizeof(*sblock), GFP_NOFS);
	if (!sblock) {
1981 1982 1983
		spin_lock(&sctx->stat_lock);
		sctx->stat.malloc_errors++;
		spin_unlock(&sctx->stat_lock);
1984
		return -ENOMEM;
A
Arne Jansen 已提交
1985
	}
1986

1987 1988
	/* one ref inside this function, plus one for each page added to
	 * a bio later on */
1989
	atomic_set(&sblock->ref_count, 1);
1990
	sblock->sctx = sctx;
1991 1992 1993
	sblock->no_io_error_seen = 1;

	for (index = 0; len > 0; index++) {
1994
		struct scrub_page *spage;
1995 1996
		u64 l = min_t(u64, len, PAGE_SIZE);

1997 1998 1999
		spage = kzalloc(sizeof(*spage), GFP_NOFS);
		if (!spage) {
leave_nomem:
2000 2001 2002
			spin_lock(&sctx->stat_lock);
			sctx->stat.malloc_errors++;
			spin_unlock(&sctx->stat_lock);
2003
			scrub_block_put(sblock);
2004 2005
			return -ENOMEM;
		}
2006 2007 2008
		BUG_ON(index >= SCRUB_MAX_PAGES_PER_BLOCK);
		scrub_page_get(spage);
		sblock->pagev[index] = spage;
2009
		spage->sblock = sblock;
2010
		spage->dev = dev;
2011 2012 2013 2014
		spage->flags = flags;
		spage->generation = gen;
		spage->logical = logical;
		spage->physical = physical;
2015
		spage->physical_for_dev_replace = physical_for_dev_replace;
2016 2017 2018
		spage->mirror_num = mirror_num;
		if (csum) {
			spage->have_csum = 1;
2019
			memcpy(spage->csum, csum, sctx->csum_size);
2020 2021 2022 2023
		} else {
			spage->have_csum = 0;
		}
		sblock->page_count++;
2024 2025 2026
		spage->page = alloc_page(GFP_NOFS);
		if (!spage->page)
			goto leave_nomem;
2027 2028 2029
		len -= l;
		logical += l;
		physical += l;
2030
		physical_for_dev_replace += l;
2031 2032
	}

2033
	WARN_ON(sblock->page_count == 0);
2034
	for (index = 0; index < sblock->page_count; index++) {
2035
		struct scrub_page *spage = sblock->pagev[index];
2036 2037
		int ret;

2038
		ret = scrub_add_page_to_rd_bio(sctx, spage);
2039 2040
		if (ret) {
			scrub_block_put(sblock);
2041
			return ret;
2042
		}
2043
	}
A
Arne Jansen 已提交
2044

2045
	if (force)
2046
		scrub_submit(sctx);
A
Arne Jansen 已提交
2047

2048 2049
	/* last one frees, either here or in bio completion for last page */
	scrub_block_put(sblock);
A
Arne Jansen 已提交
2050 2051 2052
	return 0;
}

2053 2054 2055
static void scrub_bio_end_io(struct bio *bio, int err)
{
	struct scrub_bio *sbio = bio->bi_private;
2056
	struct btrfs_fs_info *fs_info = sbio->dev->dev_root->fs_info;
2057 2058 2059 2060 2061 2062 2063 2064 2065 2066

	sbio->err = err;
	sbio->bio = bio;

	btrfs_queue_worker(&fs_info->scrub_workers, &sbio->work);
}

static void scrub_bio_end_io_worker(struct btrfs_work *work)
{
	struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
2067
	struct scrub_ctx *sctx = sbio->sctx;
2068 2069
	int i;

2070
	BUG_ON(sbio->page_count > SCRUB_PAGES_PER_RD_BIO);
2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091
	if (sbio->err) {
		for (i = 0; i < sbio->page_count; i++) {
			struct scrub_page *spage = sbio->pagev[i];

			spage->io_error = 1;
			spage->sblock->no_io_error_seen = 0;
		}
	}

	/* now complete the scrub_block items that have all pages completed */
	for (i = 0; i < sbio->page_count; i++) {
		struct scrub_page *spage = sbio->pagev[i];
		struct scrub_block *sblock = spage->sblock;

		if (atomic_dec_and_test(&sblock->outstanding_pages))
			scrub_block_complete(sblock);
		scrub_block_put(sblock);
	}

	bio_put(sbio->bio);
	sbio->bio = NULL;
2092 2093 2094 2095
	spin_lock(&sctx->list_lock);
	sbio->next_free = sctx->first_free;
	sctx->first_free = sbio->index;
	spin_unlock(&sctx->list_lock);
2096 2097 2098 2099 2100 2101 2102 2103

	if (sctx->is_dev_replace &&
	    atomic_read(&sctx->wr_ctx.flush_all_writes)) {
		mutex_lock(&sctx->wr_ctx.wr_lock);
		scrub_wr_submit(sctx);
		mutex_unlock(&sctx->wr_ctx.wr_lock);
	}

2104
	scrub_pending_bio_dec(sctx);
2105 2106 2107 2108
}

static void scrub_block_complete(struct scrub_block *sblock)
{
2109
	if (!sblock->no_io_error_seen) {
2110
		scrub_handle_errored_block(sblock);
2111 2112 2113 2114 2115 2116 2117 2118 2119
	} else {
		/*
		 * if has checksum error, write via repair mechanism in
		 * dev replace case, otherwise write here in dev replace
		 * case.
		 */
		if (!scrub_checksum(sblock) && sblock->sctx->is_dev_replace)
			scrub_write_block_to_dev_replace(sblock);
	}
2120 2121
}

2122
static int scrub_find_csum(struct scrub_ctx *sctx, u64 logical, u64 len,
A
Arne Jansen 已提交
2123 2124 2125
			   u8 *csum)
{
	struct btrfs_ordered_sum *sum = NULL;
2126
	unsigned long index;
A
Arne Jansen 已提交
2127 2128
	unsigned long num_sectors;

2129 2130
	while (!list_empty(&sctx->csum_list)) {
		sum = list_first_entry(&sctx->csum_list,
A
Arne Jansen 已提交
2131 2132 2133 2134 2135 2136
				       struct btrfs_ordered_sum, list);
		if (sum->bytenr > logical)
			return 0;
		if (sum->bytenr + sum->len > logical)
			break;

2137
		++sctx->stat.csum_discards;
A
Arne Jansen 已提交
2138 2139 2140 2141 2142 2143 2144
		list_del(&sum->list);
		kfree(sum);
		sum = NULL;
	}
	if (!sum)
		return 0;

2145
	index = ((u32)(logical - sum->bytenr)) / sctx->sectorsize;
2146
	num_sectors = sum->len / sctx->sectorsize;
2147 2148
	memcpy(csum, sum->sums + index, sctx->csum_size);
	if (index == num_sectors - 1) {
A
Arne Jansen 已提交
2149 2150 2151
		list_del(&sum->list);
		kfree(sum);
	}
2152
	return 1;
A
Arne Jansen 已提交
2153 2154 2155
}

/* scrub extent tries to collect up to 64 kB for each bio */
2156
static int scrub_extent(struct scrub_ctx *sctx, u64 logical, u64 len,
2157
			u64 physical, struct btrfs_device *dev, u64 flags,
2158
			u64 gen, int mirror_num, u64 physical_for_dev_replace)
A
Arne Jansen 已提交
2159 2160 2161
{
	int ret;
	u8 csum[BTRFS_CSUM_SIZE];
2162 2163 2164
	u32 blocksize;

	if (flags & BTRFS_EXTENT_FLAG_DATA) {
2165 2166 2167 2168 2169
		blocksize = sctx->sectorsize;
		spin_lock(&sctx->stat_lock);
		sctx->stat.data_extents_scrubbed++;
		sctx->stat.data_bytes_scrubbed += len;
		spin_unlock(&sctx->stat_lock);
2170
	} else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
2171
		WARN_ON(sctx->nodesize != sctx->leafsize);
2172 2173 2174 2175 2176
		blocksize = sctx->nodesize;
		spin_lock(&sctx->stat_lock);
		sctx->stat.tree_extents_scrubbed++;
		sctx->stat.tree_bytes_scrubbed += len;
		spin_unlock(&sctx->stat_lock);
2177
	} else {
2178
		blocksize = sctx->sectorsize;
2179
		WARN_ON(1);
2180
	}
A
Arne Jansen 已提交
2181 2182

	while (len) {
2183
		u64 l = min_t(u64, len, blocksize);
A
Arne Jansen 已提交
2184 2185 2186 2187
		int have_csum = 0;

		if (flags & BTRFS_EXTENT_FLAG_DATA) {
			/* push csums to sbio */
2188
			have_csum = scrub_find_csum(sctx, logical, l, csum);
A
Arne Jansen 已提交
2189
			if (have_csum == 0)
2190
				++sctx->stat.no_csum;
2191 2192 2193 2194 2195 2196
			if (sctx->is_dev_replace && !have_csum) {
				ret = copy_nocow_pages(sctx, logical, l,
						       mirror_num,
						      physical_for_dev_replace);
				goto behind_scrub_pages;
			}
A
Arne Jansen 已提交
2197
		}
2198
		ret = scrub_pages(sctx, logical, l, physical, dev, flags, gen,
2199 2200 2201
				  mirror_num, have_csum ? csum : NULL, 0,
				  physical_for_dev_replace);
behind_scrub_pages:
A
Arne Jansen 已提交
2202 2203 2204 2205 2206
		if (ret)
			return ret;
		len -= l;
		logical += l;
		physical += l;
2207
		physical_for_dev_replace += l;
A
Arne Jansen 已提交
2208 2209 2210 2211
	}
	return 0;
}

2212
static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
2213 2214
					   struct map_lookup *map,
					   struct btrfs_device *scrub_dev,
2215 2216
					   int num, u64 base, u64 length,
					   int is_dev_replace)
A
Arne Jansen 已提交
2217 2218
{
	struct btrfs_path *path;
2219
	struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;
A
Arne Jansen 已提交
2220 2221 2222
	struct btrfs_root *root = fs_info->extent_root;
	struct btrfs_root *csum_root = fs_info->csum_root;
	struct btrfs_extent_item *extent;
2223
	struct blk_plug plug;
A
Arne Jansen 已提交
2224 2225 2226 2227 2228 2229 2230 2231
	u64 flags;
	int ret;
	int slot;
	u64 nstripes;
	struct extent_buffer *l;
	struct btrfs_key key;
	u64 physical;
	u64 logical;
L
Liu Bo 已提交
2232
	u64 logic_end;
A
Arne Jansen 已提交
2233
	u64 generation;
2234
	int mirror_num;
A
Arne Jansen 已提交
2235 2236 2237 2238
	struct reada_control *reada1;
	struct reada_control *reada2;
	struct btrfs_key key_start;
	struct btrfs_key key_end;
A
Arne Jansen 已提交
2239 2240
	u64 increment = map->stripe_len;
	u64 offset;
2241 2242 2243 2244 2245
	u64 extent_logical;
	u64 extent_physical;
	u64 extent_len;
	struct btrfs_device *extent_dev;
	int extent_mirror_num;
L
Liu Bo 已提交
2246
	int stop_loop;
A
Arne Jansen 已提交
2247

D
David Woodhouse 已提交
2248 2249 2250 2251 2252 2253 2254
	if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
			 BTRFS_BLOCK_GROUP_RAID6)) {
		if (num >= nr_data_stripes(map)) {
			return 0;
		}
	}

A
Arne Jansen 已提交
2255 2256 2257 2258 2259 2260
	nstripes = length;
	offset = 0;
	do_div(nstripes, map->stripe_len);
	if (map->type & BTRFS_BLOCK_GROUP_RAID0) {
		offset = map->stripe_len * num;
		increment = map->stripe_len * map->num_stripes;
2261
		mirror_num = 1;
A
Arne Jansen 已提交
2262 2263 2264 2265
	} else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
		int factor = map->num_stripes / map->sub_stripes;
		offset = map->stripe_len * (num / map->sub_stripes);
		increment = map->stripe_len * factor;
2266
		mirror_num = num % map->sub_stripes + 1;
A
Arne Jansen 已提交
2267 2268
	} else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
		increment = map->stripe_len;
2269
		mirror_num = num % map->num_stripes + 1;
A
Arne Jansen 已提交
2270 2271
	} else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
		increment = map->stripe_len;
2272
		mirror_num = num % map->num_stripes + 1;
A
Arne Jansen 已提交
2273 2274
	} else {
		increment = map->stripe_len;
2275
		mirror_num = 1;
A
Arne Jansen 已提交
2276 2277 2278 2279 2280 2281
	}

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;

2282 2283 2284 2285 2286
	/*
	 * work on commit root. The related disk blocks are static as
	 * long as COW is applied. This means, it is save to rewrite
	 * them to repair disk errors without any race conditions
	 */
A
Arne Jansen 已提交
2287 2288 2289 2290
	path->search_commit_root = 1;
	path->skip_locking = 1;

	/*
A
Arne Jansen 已提交
2291 2292 2293
	 * trigger the readahead for extent tree csum tree and wait for
	 * completion. During readahead, the scrub is officially paused
	 * to not hold off transaction commits
A
Arne Jansen 已提交
2294 2295 2296
	 */
	logical = base + offset;

2297
	wait_event(sctx->list_wait,
2298
		   atomic_read(&sctx->bios_in_flight) == 0);
A
Arne Jansen 已提交
2299 2300 2301 2302 2303 2304 2305 2306
	atomic_inc(&fs_info->scrubs_paused);
	wake_up(&fs_info->scrub_pause_wait);

	/* FIXME it might be better to start readahead at commit root */
	key_start.objectid = logical;
	key_start.type = BTRFS_EXTENT_ITEM_KEY;
	key_start.offset = (u64)0;
	key_end.objectid = base + offset + nstripes * increment;
2307 2308
	key_end.type = BTRFS_METADATA_ITEM_KEY;
	key_end.offset = (u64)-1;
A
Arne Jansen 已提交
2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329
	reada1 = btrfs_reada_add(root, &key_start, &key_end);

	key_start.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
	key_start.type = BTRFS_EXTENT_CSUM_KEY;
	key_start.offset = logical;
	key_end.objectid = BTRFS_EXTENT_CSUM_OBJECTID;
	key_end.type = BTRFS_EXTENT_CSUM_KEY;
	key_end.offset = base + offset + nstripes * increment;
	reada2 = btrfs_reada_add(csum_root, &key_start, &key_end);

	if (!IS_ERR(reada1))
		btrfs_reada_wait(reada1);
	if (!IS_ERR(reada2))
		btrfs_reada_wait(reada2);

	mutex_lock(&fs_info->scrub_lock);
	while (atomic_read(&fs_info->scrub_pause_req)) {
		mutex_unlock(&fs_info->scrub_lock);
		wait_event(fs_info->scrub_pause_wait,
		   atomic_read(&fs_info->scrub_pause_req) == 0);
		mutex_lock(&fs_info->scrub_lock);
A
Arne Jansen 已提交
2330
	}
A
Arne Jansen 已提交
2331 2332 2333
	atomic_dec(&fs_info->scrubs_paused);
	mutex_unlock(&fs_info->scrub_lock);
	wake_up(&fs_info->scrub_pause_wait);
A
Arne Jansen 已提交
2334 2335 2336 2337 2338

	/*
	 * collect all data csums for the stripe to avoid seeking during
	 * the scrub. This might currently (crc32) end up to be about 1MB
	 */
2339
	blk_start_plug(&plug);
A
Arne Jansen 已提交
2340 2341 2342 2343

	/*
	 * now find all extents for each stripe and scrub them
	 */
A
Arne Jansen 已提交
2344 2345
	logical = base + offset;
	physical = map->stripes[num].physical;
L
Liu Bo 已提交
2346
	logic_end = logical + increment * nstripes;
A
Arne Jansen 已提交
2347
	ret = 0;
L
Liu Bo 已提交
2348
	while (logical < logic_end) {
A
Arne Jansen 已提交
2349 2350 2351 2352
		/*
		 * canceled?
		 */
		if (atomic_read(&fs_info->scrub_cancel_req) ||
2353
		    atomic_read(&sctx->cancel_req)) {
A
Arne Jansen 已提交
2354 2355 2356 2357 2358 2359 2360 2361
			ret = -ECANCELED;
			goto out;
		}
		/*
		 * check to see if we have to pause
		 */
		if (atomic_read(&fs_info->scrub_pause_req)) {
			/* push queued extents */
2362
			atomic_set(&sctx->wr_ctx.flush_all_writes, 1);
2363
			scrub_submit(sctx);
2364 2365 2366
			mutex_lock(&sctx->wr_ctx.wr_lock);
			scrub_wr_submit(sctx);
			mutex_unlock(&sctx->wr_ctx.wr_lock);
2367
			wait_event(sctx->list_wait,
2368
				   atomic_read(&sctx->bios_in_flight) == 0);
2369
			atomic_set(&sctx->wr_ctx.flush_all_writes, 0);
A
Arne Jansen 已提交
2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385
			atomic_inc(&fs_info->scrubs_paused);
			wake_up(&fs_info->scrub_pause_wait);
			mutex_lock(&fs_info->scrub_lock);
			while (atomic_read(&fs_info->scrub_pause_req)) {
				mutex_unlock(&fs_info->scrub_lock);
				wait_event(fs_info->scrub_pause_wait,
				   atomic_read(&fs_info->scrub_pause_req) == 0);
				mutex_lock(&fs_info->scrub_lock);
			}
			atomic_dec(&fs_info->scrubs_paused);
			mutex_unlock(&fs_info->scrub_lock);
			wake_up(&fs_info->scrub_pause_wait);
		}

		key.objectid = logical;
		key.type = BTRFS_EXTENT_ITEM_KEY;
L
Liu Bo 已提交
2386
		key.offset = (u64)-1;
A
Arne Jansen 已提交
2387 2388 2389 2390

		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
		if (ret < 0)
			goto out;
2391

2392
		if (ret > 0) {
A
Arne Jansen 已提交
2393 2394 2395 2396
			ret = btrfs_previous_item(root, path, 0,
						  BTRFS_EXTENT_ITEM_KEY);
			if (ret < 0)
				goto out;
2397 2398 2399 2400 2401 2402 2403 2404 2405
			if (ret > 0) {
				/* there's no smaller item, so stick with the
				 * larger one */
				btrfs_release_path(path);
				ret = btrfs_search_slot(NULL, root, &key,
							path, 0, 0);
				if (ret < 0)
					goto out;
			}
A
Arne Jansen 已提交
2406 2407
		}

L
Liu Bo 已提交
2408
		stop_loop = 0;
A
Arne Jansen 已提交
2409
		while (1) {
2410 2411
			u64 bytes;

A
Arne Jansen 已提交
2412 2413 2414 2415 2416 2417 2418 2419 2420
			l = path->nodes[0];
			slot = path->slots[0];
			if (slot >= btrfs_header_nritems(l)) {
				ret = btrfs_next_leaf(root, path);
				if (ret == 0)
					continue;
				if (ret < 0)
					goto out;

L
Liu Bo 已提交
2421
				stop_loop = 1;
A
Arne Jansen 已提交
2422 2423 2424 2425
				break;
			}
			btrfs_item_key_to_cpu(l, &key, slot);

2426 2427 2428 2429 2430 2431
			if (key.type == BTRFS_METADATA_ITEM_KEY)
				bytes = root->leafsize;
			else
				bytes = key.offset;

			if (key.objectid + bytes <= logical)
A
Arne Jansen 已提交
2432 2433
				goto next;

L
Liu Bo 已提交
2434 2435 2436
			if (key.type != BTRFS_EXTENT_ITEM_KEY &&
			    key.type != BTRFS_METADATA_ITEM_KEY)
				goto next;
A
Arne Jansen 已提交
2437

L
Liu Bo 已提交
2438 2439 2440 2441 2442 2443
			if (key.objectid >= logical + map->stripe_len) {
				/* out of this device extent */
				if (key.objectid >= logic_end)
					stop_loop = 1;
				break;
			}
A
Arne Jansen 已提交
2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454

			extent = btrfs_item_ptr(l, slot,
						struct btrfs_extent_item);
			flags = btrfs_extent_flags(l, extent);
			generation = btrfs_extent_generation(l, extent);

			if (key.objectid < logical &&
			    (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) {
				printk(KERN_ERR
				       "btrfs scrub: tree block %llu spanning "
				       "stripes, ignored. logical=%llu\n",
2455
				       key.objectid, logical);
A
Arne Jansen 已提交
2456 2457 2458
				goto next;
			}

L
Liu Bo 已提交
2459 2460 2461 2462
again:
			extent_logical = key.objectid;
			extent_len = bytes;

A
Arne Jansen 已提交
2463 2464 2465
			/*
			 * trim extent to this stripe
			 */
L
Liu Bo 已提交
2466 2467 2468
			if (extent_logical < logical) {
				extent_len -= logical - extent_logical;
				extent_logical = logical;
A
Arne Jansen 已提交
2469
			}
L
Liu Bo 已提交
2470
			if (extent_logical + extent_len >
A
Arne Jansen 已提交
2471
			    logical + map->stripe_len) {
L
Liu Bo 已提交
2472 2473
				extent_len = logical + map->stripe_len -
					     extent_logical;
A
Arne Jansen 已提交
2474 2475
			}

L
Liu Bo 已提交
2476
			extent_physical = extent_logical - logical + physical;
2477 2478 2479 2480 2481 2482 2483
			extent_dev = scrub_dev;
			extent_mirror_num = mirror_num;
			if (is_dev_replace)
				scrub_remap_extent(fs_info, extent_logical,
						   extent_len, &extent_physical,
						   &extent_dev,
						   &extent_mirror_num);
L
Liu Bo 已提交
2484 2485 2486 2487 2488 2489 2490

			ret = btrfs_lookup_csums_range(csum_root, logical,
						logical + map->stripe_len - 1,
						&sctx->csum_list, 1);
			if (ret)
				goto out;

2491 2492 2493
			ret = scrub_extent(sctx, extent_logical, extent_len,
					   extent_physical, extent_dev, flags,
					   generation, extent_mirror_num,
2494
					   extent_logical - logical + physical);
A
Arne Jansen 已提交
2495 2496 2497
			if (ret)
				goto out;

2498
			scrub_free_csums(sctx);
L
Liu Bo 已提交
2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513
			if (extent_logical + extent_len <
			    key.objectid + bytes) {
				logical += increment;
				physical += map->stripe_len;

				if (logical < key.objectid + bytes) {
					cond_resched();
					goto again;
				}

				if (logical >= logic_end) {
					stop_loop = 1;
					break;
				}
			}
A
Arne Jansen 已提交
2514 2515 2516
next:
			path->slots[0]++;
		}
C
Chris Mason 已提交
2517
		btrfs_release_path(path);
A
Arne Jansen 已提交
2518 2519
		logical += increment;
		physical += map->stripe_len;
2520
		spin_lock(&sctx->stat_lock);
L
Liu Bo 已提交
2521 2522 2523 2524 2525
		if (stop_loop)
			sctx->stat.last_physical = map->stripes[num].physical +
						   length;
		else
			sctx->stat.last_physical = physical;
2526
		spin_unlock(&sctx->stat_lock);
L
Liu Bo 已提交
2527 2528
		if (stop_loop)
			break;
A
Arne Jansen 已提交
2529
	}
2530
out:
A
Arne Jansen 已提交
2531
	/* push queued extents */
2532
	scrub_submit(sctx);
2533 2534 2535
	mutex_lock(&sctx->wr_ctx.wr_lock);
	scrub_wr_submit(sctx);
	mutex_unlock(&sctx->wr_ctx.wr_lock);
A
Arne Jansen 已提交
2536

2537
	blk_finish_plug(&plug);
A
Arne Jansen 已提交
2538 2539 2540 2541
	btrfs_free_path(path);
	return ret < 0 ? ret : 0;
}

2542
static noinline_for_stack int scrub_chunk(struct scrub_ctx *sctx,
2543 2544 2545
					  struct btrfs_device *scrub_dev,
					  u64 chunk_tree, u64 chunk_objectid,
					  u64 chunk_offset, u64 length,
2546
					  u64 dev_offset, int is_dev_replace)
A
Arne Jansen 已提交
2547 2548
{
	struct btrfs_mapping_tree *map_tree =
2549
		&sctx->dev_root->fs_info->mapping_tree;
A
Arne Jansen 已提交
2550 2551 2552
	struct map_lookup *map;
	struct extent_map *em;
	int i;
2553
	int ret = 0;
A
Arne Jansen 已提交
2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569

	read_lock(&map_tree->map_tree.lock);
	em = lookup_extent_mapping(&map_tree->map_tree, chunk_offset, 1);
	read_unlock(&map_tree->map_tree.lock);

	if (!em)
		return -EINVAL;

	map = (struct map_lookup *)em->bdev;
	if (em->start != chunk_offset)
		goto out;

	if (em->len < length)
		goto out;

	for (i = 0; i < map->num_stripes; ++i) {
2570
		if (map->stripes[i].dev->bdev == scrub_dev->bdev &&
2571
		    map->stripes[i].physical == dev_offset) {
2572
			ret = scrub_stripe(sctx, map, scrub_dev, i,
2573 2574
					   chunk_offset, length,
					   is_dev_replace);
A
Arne Jansen 已提交
2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585
			if (ret)
				goto out;
		}
	}
out:
	free_extent_map(em);

	return ret;
}

static noinline_for_stack
2586
int scrub_enumerate_chunks(struct scrub_ctx *sctx,
2587 2588
			   struct btrfs_device *scrub_dev, u64 start, u64 end,
			   int is_dev_replace)
A
Arne Jansen 已提交
2589 2590 2591
{
	struct btrfs_dev_extent *dev_extent = NULL;
	struct btrfs_path *path;
2592
	struct btrfs_root *root = sctx->dev_root;
A
Arne Jansen 已提交
2593 2594 2595 2596 2597 2598 2599 2600 2601 2602 2603
	struct btrfs_fs_info *fs_info = root->fs_info;
	u64 length;
	u64 chunk_tree;
	u64 chunk_objectid;
	u64 chunk_offset;
	int ret;
	int slot;
	struct extent_buffer *l;
	struct btrfs_key key;
	struct btrfs_key found_key;
	struct btrfs_block_group_cache *cache;
2604
	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
A
Arne Jansen 已提交
2605 2606 2607 2608 2609 2610 2611 2612 2613

	path = btrfs_alloc_path();
	if (!path)
		return -ENOMEM;

	path->reada = 2;
	path->search_commit_root = 1;
	path->skip_locking = 1;

2614
	key.objectid = scrub_dev->devid;
A
Arne Jansen 已提交
2615 2616 2617 2618 2619 2620
	key.offset = 0ull;
	key.type = BTRFS_DEV_EXTENT_KEY;

	while (1) {
		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
		if (ret < 0)
2621 2622 2623 2624 2625 2626 2627 2628 2629
			break;
		if (ret > 0) {
			if (path->slots[0] >=
			    btrfs_header_nritems(path->nodes[0])) {
				ret = btrfs_next_leaf(root, path);
				if (ret)
					break;
			}
		}
A
Arne Jansen 已提交
2630 2631 2632 2633 2634 2635

		l = path->nodes[0];
		slot = path->slots[0];

		btrfs_item_key_to_cpu(l, &found_key, slot);

2636
		if (found_key.objectid != scrub_dev->devid)
A
Arne Jansen 已提交
2637 2638
			break;

2639
		if (btrfs_key_type(&found_key) != BTRFS_DEV_EXTENT_KEY)
A
Arne Jansen 已提交
2640 2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652
			break;

		if (found_key.offset >= end)
			break;

		if (found_key.offset < key.offset)
			break;

		dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
		length = btrfs_dev_extent_length(l, dev_extent);

		if (found_key.offset + length <= start) {
			key.offset = found_key.offset + length;
C
Chris Mason 已提交
2653
			btrfs_release_path(path);
A
Arne Jansen 已提交
2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667
			continue;
		}

		chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
		chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
		chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);

		/*
		 * get a reference on the corresponding block group to prevent
		 * the chunk from going away while we scrub it
		 */
		cache = btrfs_lookup_block_group(fs_info, chunk_offset);
		if (!cache) {
			ret = -ENOENT;
2668
			break;
A
Arne Jansen 已提交
2669
		}
2670 2671 2672
		dev_replace->cursor_right = found_key.offset + length;
		dev_replace->cursor_left = found_key.offset;
		dev_replace->item_needs_writeback = 1;
2673
		ret = scrub_chunk(sctx, scrub_dev, chunk_tree, chunk_objectid,
2674 2675 2676 2677 2678 2679 2680 2681 2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711 2712 2713
				  chunk_offset, length, found_key.offset,
				  is_dev_replace);

		/*
		 * flush, submit all pending read and write bios, afterwards
		 * wait for them.
		 * Note that in the dev replace case, a read request causes
		 * write requests that are submitted in the read completion
		 * worker. Therefore in the current situation, it is required
		 * that all write requests are flushed, so that all read and
		 * write requests are really completed when bios_in_flight
		 * changes to 0.
		 */
		atomic_set(&sctx->wr_ctx.flush_all_writes, 1);
		scrub_submit(sctx);
		mutex_lock(&sctx->wr_ctx.wr_lock);
		scrub_wr_submit(sctx);
		mutex_unlock(&sctx->wr_ctx.wr_lock);

		wait_event(sctx->list_wait,
			   atomic_read(&sctx->bios_in_flight) == 0);
		atomic_set(&sctx->wr_ctx.flush_all_writes, 0);
		atomic_inc(&fs_info->scrubs_paused);
		wake_up(&fs_info->scrub_pause_wait);
		wait_event(sctx->list_wait,
			   atomic_read(&sctx->workers_pending) == 0);

		mutex_lock(&fs_info->scrub_lock);
		while (atomic_read(&fs_info->scrub_pause_req)) {
			mutex_unlock(&fs_info->scrub_lock);
			wait_event(fs_info->scrub_pause_wait,
			   atomic_read(&fs_info->scrub_pause_req) == 0);
			mutex_lock(&fs_info->scrub_lock);
		}
		atomic_dec(&fs_info->scrubs_paused);
		mutex_unlock(&fs_info->scrub_lock);
		wake_up(&fs_info->scrub_pause_wait);

		dev_replace->cursor_left = dev_replace->cursor_right;
		dev_replace->item_needs_writeback = 1;
A
Arne Jansen 已提交
2714 2715 2716
		btrfs_put_block_group(cache);
		if (ret)
			break;
2717 2718
		if (is_dev_replace &&
		    atomic64_read(&dev_replace->num_write_errors) > 0) {
2719 2720 2721 2722 2723 2724 2725
			ret = -EIO;
			break;
		}
		if (sctx->stat.malloc_errors > 0) {
			ret = -ENOMEM;
			break;
		}
A
Arne Jansen 已提交
2726 2727

		key.offset = found_key.offset + length;
C
Chris Mason 已提交
2728
		btrfs_release_path(path);
A
Arne Jansen 已提交
2729 2730 2731
	}

	btrfs_free_path(path);
2732 2733 2734 2735 2736 2737

	/*
	 * ret can still be 1 from search_slot or next_leaf,
	 * that's not an error
	 */
	return ret < 0 ? ret : 0;
A
Arne Jansen 已提交
2738 2739
}

2740 2741
static noinline_for_stack int scrub_supers(struct scrub_ctx *sctx,
					   struct btrfs_device *scrub_dev)
A
Arne Jansen 已提交
2742 2743 2744 2745 2746
{
	int	i;
	u64	bytenr;
	u64	gen;
	int	ret;
2747
	struct btrfs_root *root = sctx->dev_root;
A
Arne Jansen 已提交
2748

2749
	if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
2750 2751
		return -EIO;

A
Arne Jansen 已提交
2752 2753 2754 2755
	gen = root->fs_info->last_trans_committed;

	for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
		bytenr = btrfs_sb_offset(i);
2756
		if (bytenr + BTRFS_SUPER_INFO_SIZE > scrub_dev->total_bytes)
A
Arne Jansen 已提交
2757 2758
			break;

2759
		ret = scrub_pages(sctx, bytenr, BTRFS_SUPER_INFO_SIZE, bytenr,
2760
				  scrub_dev, BTRFS_EXTENT_FLAG_SUPER, gen, i,
2761
				  NULL, 1, bytenr);
A
Arne Jansen 已提交
2762 2763 2764
		if (ret)
			return ret;
	}
2765
	wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0);
A
Arne Jansen 已提交
2766 2767 2768 2769 2770 2771 2772

	return 0;
}

/*
 * get a reference count on fs_info->scrub_workers. start worker if necessary
 */
2773 2774
static noinline_for_stack int scrub_workers_get(struct btrfs_fs_info *fs_info,
						int is_dev_replace)
A
Arne Jansen 已提交
2775
{
2776
	int ret = 0;
A
Arne Jansen 已提交
2777 2778

	mutex_lock(&fs_info->scrub_lock);
A
Arne Jansen 已提交
2779
	if (fs_info->scrub_workers_refcnt == 0) {
2780 2781 2782 2783 2784 2785 2786
		if (is_dev_replace)
			btrfs_init_workers(&fs_info->scrub_workers, "scrub", 1,
					&fs_info->generic_worker);
		else
			btrfs_init_workers(&fs_info->scrub_workers, "scrub",
					fs_info->thread_pool_size,
					&fs_info->generic_worker);
A
Arne Jansen 已提交
2787
		fs_info->scrub_workers.idle_thresh = 4;
2788 2789 2790
		ret = btrfs_start_workers(&fs_info->scrub_workers);
		if (ret)
			goto out;
2791 2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804
		btrfs_init_workers(&fs_info->scrub_wr_completion_workers,
				   "scrubwrc",
				   fs_info->thread_pool_size,
				   &fs_info->generic_worker);
		fs_info->scrub_wr_completion_workers.idle_thresh = 2;
		ret = btrfs_start_workers(
				&fs_info->scrub_wr_completion_workers);
		if (ret)
			goto out;
		btrfs_init_workers(&fs_info->scrub_nocow_workers, "scrubnc", 1,
				   &fs_info->generic_worker);
		ret = btrfs_start_workers(&fs_info->scrub_nocow_workers);
		if (ret)
			goto out;
A
Arne Jansen 已提交
2805
	}
A
Arne Jansen 已提交
2806
	++fs_info->scrub_workers_refcnt;
2807
out:
A
Arne Jansen 已提交
2808 2809
	mutex_unlock(&fs_info->scrub_lock);

2810
	return ret;
A
Arne Jansen 已提交
2811 2812
}

2813
static noinline_for_stack void scrub_workers_put(struct btrfs_fs_info *fs_info)
A
Arne Jansen 已提交
2814 2815
{
	mutex_lock(&fs_info->scrub_lock);
2816
	if (--fs_info->scrub_workers_refcnt == 0) {
A
Arne Jansen 已提交
2817
		btrfs_stop_workers(&fs_info->scrub_workers);
2818 2819 2820
		btrfs_stop_workers(&fs_info->scrub_wr_completion_workers);
		btrfs_stop_workers(&fs_info->scrub_nocow_workers);
	}
A
Arne Jansen 已提交
2821 2822 2823 2824
	WARN_ON(fs_info->scrub_workers_refcnt < 0);
	mutex_unlock(&fs_info->scrub_lock);
}

2825 2826
int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
		    u64 end, struct btrfs_scrub_progress *progress,
2827
		    int readonly, int is_dev_replace)
A
Arne Jansen 已提交
2828
{
2829
	struct scrub_ctx *sctx;
A
Arne Jansen 已提交
2830 2831 2832
	int ret;
	struct btrfs_device *dev;

2833
	if (btrfs_fs_closing(fs_info))
A
Arne Jansen 已提交
2834 2835 2836 2837 2838
		return -EINVAL;

	/*
	 * check some assumptions
	 */
2839
	if (fs_info->chunk_root->nodesize != fs_info->chunk_root->leafsize) {
2840 2841
		printk(KERN_ERR
		       "btrfs_scrub: size assumption nodesize == leafsize (%d == %d) fails\n",
2842 2843
		       fs_info->chunk_root->nodesize,
		       fs_info->chunk_root->leafsize);
2844 2845 2846
		return -EINVAL;
	}

2847
	if (fs_info->chunk_root->nodesize > BTRFS_STRIPE_LEN) {
2848 2849 2850 2851 2852 2853 2854
		/*
		 * in this case scrub is unable to calculate the checksum
		 * the way scrub is implemented. Do not handle this
		 * situation at all because it won't ever happen.
		 */
		printk(KERN_ERR
		       "btrfs_scrub: size assumption nodesize <= BTRFS_STRIPE_LEN (%d <= %d) fails\n",
2855
		       fs_info->chunk_root->nodesize, BTRFS_STRIPE_LEN);
2856 2857 2858
		return -EINVAL;
	}

2859
	if (fs_info->chunk_root->sectorsize != PAGE_SIZE) {
2860 2861
		/* not supported for data w/o checksums */
		printk(KERN_ERR
2862 2863
		       "btrfs_scrub: size assumption sectorsize != PAGE_SIZE (%d != %lu) fails\n",
		       fs_info->chunk_root->sectorsize, PAGE_SIZE);
A
Arne Jansen 已提交
2864 2865 2866
		return -EINVAL;
	}

2867 2868 2869 2870 2871 2872 2873 2874 2875 2876 2877 2878 2879 2880 2881 2882
	if (fs_info->chunk_root->nodesize >
	    PAGE_SIZE * SCRUB_MAX_PAGES_PER_BLOCK ||
	    fs_info->chunk_root->sectorsize >
	    PAGE_SIZE * SCRUB_MAX_PAGES_PER_BLOCK) {
		/*
		 * would exhaust the array bounds of pagev member in
		 * struct scrub_block
		 */
		pr_err("btrfs_scrub: size assumption nodesize and sectorsize <= SCRUB_MAX_PAGES_PER_BLOCK (%d <= %d && %d <= %d) fails\n",
		       fs_info->chunk_root->nodesize,
		       SCRUB_MAX_PAGES_PER_BLOCK,
		       fs_info->chunk_root->sectorsize,
		       SCRUB_MAX_PAGES_PER_BLOCK);
		return -EINVAL;
	}

2883
	ret = scrub_workers_get(fs_info, is_dev_replace);
A
Arne Jansen 已提交
2884 2885 2886
	if (ret)
		return ret;

2887 2888
	mutex_lock(&fs_info->fs_devices->device_list_mutex);
	dev = btrfs_find_device(fs_info, devid, NULL, NULL);
2889
	if (!dev || (dev->missing && !is_dev_replace)) {
2890 2891
		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
		scrub_workers_put(fs_info);
A
Arne Jansen 已提交
2892 2893 2894 2895
		return -ENODEV;
	}
	mutex_lock(&fs_info->scrub_lock);

2896
	if (!dev->in_fs_metadata || dev->is_tgtdev_for_dev_replace) {
A
Arne Jansen 已提交
2897
		mutex_unlock(&fs_info->scrub_lock);
2898 2899 2900
		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
		scrub_workers_put(fs_info);
		return -EIO;
A
Arne Jansen 已提交
2901 2902
	}

2903 2904 2905 2906 2907
	btrfs_dev_replace_lock(&fs_info->dev_replace);
	if (dev->scrub_device ||
	    (!is_dev_replace &&
	     btrfs_dev_replace_is_ongoing(&fs_info->dev_replace))) {
		btrfs_dev_replace_unlock(&fs_info->dev_replace);
A
Arne Jansen 已提交
2908
		mutex_unlock(&fs_info->scrub_lock);
2909 2910
		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
		scrub_workers_put(fs_info);
A
Arne Jansen 已提交
2911 2912
		return -EINPROGRESS;
	}
2913
	btrfs_dev_replace_unlock(&fs_info->dev_replace);
2914
	sctx = scrub_setup_ctx(dev, is_dev_replace);
2915
	if (IS_ERR(sctx)) {
A
Arne Jansen 已提交
2916
		mutex_unlock(&fs_info->scrub_lock);
2917 2918
		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
		scrub_workers_put(fs_info);
2919
		return PTR_ERR(sctx);
A
Arne Jansen 已提交
2920
	}
2921 2922
	sctx->readonly = readonly;
	dev->scrub_device = sctx;
A
Arne Jansen 已提交
2923 2924 2925

	atomic_inc(&fs_info->scrubs_running);
	mutex_unlock(&fs_info->scrub_lock);
2926
	mutex_unlock(&fs_info->fs_devices->device_list_mutex);
A
Arne Jansen 已提交
2927

2928 2929 2930 2931 2932
	if (!is_dev_replace) {
		down_read(&fs_info->scrub_super_lock);
		ret = scrub_supers(sctx, dev);
		up_read(&fs_info->scrub_super_lock);
	}
A
Arne Jansen 已提交
2933 2934

	if (!ret)
2935 2936
		ret = scrub_enumerate_chunks(sctx, dev, start, end,
					     is_dev_replace);
A
Arne Jansen 已提交
2937

2938
	wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0);
A
Arne Jansen 已提交
2939 2940 2941
	atomic_dec(&fs_info->scrubs_running);
	wake_up(&fs_info->scrub_pause_wait);

2942
	wait_event(sctx->list_wait, atomic_read(&sctx->workers_pending) == 0);
2943

A
Arne Jansen 已提交
2944
	if (progress)
2945
		memcpy(progress, &sctx->stat, sizeof(*progress));
A
Arne Jansen 已提交
2946 2947 2948 2949 2950

	mutex_lock(&fs_info->scrub_lock);
	dev->scrub_device = NULL;
	mutex_unlock(&fs_info->scrub_lock);

2951
	scrub_free_ctx(sctx);
2952
	scrub_workers_put(fs_info);
A
Arne Jansen 已提交
2953 2954 2955 2956

	return ret;
}

2957
void btrfs_scrub_pause(struct btrfs_root *root)
A
Arne Jansen 已提交
2958 2959 2960 2961 2962 2963 2964 2965 2966 2967 2968 2969 2970 2971 2972 2973
{
	struct btrfs_fs_info *fs_info = root->fs_info;

	mutex_lock(&fs_info->scrub_lock);
	atomic_inc(&fs_info->scrub_pause_req);
	while (atomic_read(&fs_info->scrubs_paused) !=
	       atomic_read(&fs_info->scrubs_running)) {
		mutex_unlock(&fs_info->scrub_lock);
		wait_event(fs_info->scrub_pause_wait,
			   atomic_read(&fs_info->scrubs_paused) ==
			   atomic_read(&fs_info->scrubs_running));
		mutex_lock(&fs_info->scrub_lock);
	}
	mutex_unlock(&fs_info->scrub_lock);
}

2974
void btrfs_scrub_continue(struct btrfs_root *root)
A
Arne Jansen 已提交
2975 2976 2977 2978 2979 2980 2981
{
	struct btrfs_fs_info *fs_info = root->fs_info;

	atomic_dec(&fs_info->scrub_pause_req);
	wake_up(&fs_info->scrub_pause_wait);
}

2982
void btrfs_scrub_pause_super(struct btrfs_root *root)
A
Arne Jansen 已提交
2983 2984 2985 2986
{
	down_write(&root->fs_info->scrub_super_lock);
}

2987
void btrfs_scrub_continue_super(struct btrfs_root *root)
A
Arne Jansen 已提交
2988 2989 2990 2991
{
	up_write(&root->fs_info->scrub_super_lock);
}

2992
int btrfs_scrub_cancel(struct btrfs_fs_info *fs_info)
A
Arne Jansen 已提交
2993 2994 2995 2996 2997 2998 2999 3000 3001 3002 3003 3004 3005 3006 3007 3008 3009 3010 3011 3012
{
	mutex_lock(&fs_info->scrub_lock);
	if (!atomic_read(&fs_info->scrubs_running)) {
		mutex_unlock(&fs_info->scrub_lock);
		return -ENOTCONN;
	}

	atomic_inc(&fs_info->scrub_cancel_req);
	while (atomic_read(&fs_info->scrubs_running)) {
		mutex_unlock(&fs_info->scrub_lock);
		wait_event(fs_info->scrub_pause_wait,
			   atomic_read(&fs_info->scrubs_running) == 0);
		mutex_lock(&fs_info->scrub_lock);
	}
	atomic_dec(&fs_info->scrub_cancel_req);
	mutex_unlock(&fs_info->scrub_lock);

	return 0;
}

3013 3014
int btrfs_scrub_cancel_dev(struct btrfs_fs_info *fs_info,
			   struct btrfs_device *dev)
3015
{
3016
	struct scrub_ctx *sctx;
A
Arne Jansen 已提交
3017 3018

	mutex_lock(&fs_info->scrub_lock);
3019 3020
	sctx = dev->scrub_device;
	if (!sctx) {
A
Arne Jansen 已提交
3021 3022 3023
		mutex_unlock(&fs_info->scrub_lock);
		return -ENOTCONN;
	}
3024
	atomic_inc(&sctx->cancel_req);
A
Arne Jansen 已提交
3025 3026 3027 3028 3029 3030 3031 3032 3033 3034
	while (dev->scrub_device) {
		mutex_unlock(&fs_info->scrub_lock);
		wait_event(fs_info->scrub_pause_wait,
			   dev->scrub_device == NULL);
		mutex_lock(&fs_info->scrub_lock);
	}
	mutex_unlock(&fs_info->scrub_lock);

	return 0;
}
S
Stefan Behrens 已提交
3035

A
Arne Jansen 已提交
3036 3037 3038 3039
int btrfs_scrub_progress(struct btrfs_root *root, u64 devid,
			 struct btrfs_scrub_progress *progress)
{
	struct btrfs_device *dev;
3040
	struct scrub_ctx *sctx = NULL;
A
Arne Jansen 已提交
3041 3042

	mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
3043
	dev = btrfs_find_device(root->fs_info, devid, NULL, NULL);
A
Arne Jansen 已提交
3044
	if (dev)
3045 3046 3047
		sctx = dev->scrub_device;
	if (sctx)
		memcpy(progress, &sctx->stat, sizeof(*progress));
A
Arne Jansen 已提交
3048 3049
	mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);

3050
	return dev ? (sctx ? 0 : -ENOTCONN) : -ENODEV;
A
Arne Jansen 已提交
3051
}
3052 3053 3054 3055 3056 3057 3058 3059 3060 3061 3062 3063 3064 3065 3066 3067 3068 3069 3070 3071 3072 3073 3074 3075 3076 3077 3078 3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099 3100 3101 3102 3103 3104 3105 3106 3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127 3128 3129 3130 3131 3132 3133 3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173

static void scrub_remap_extent(struct btrfs_fs_info *fs_info,
			       u64 extent_logical, u64 extent_len,
			       u64 *extent_physical,
			       struct btrfs_device **extent_dev,
			       int *extent_mirror_num)
{
	u64 mapped_length;
	struct btrfs_bio *bbio = NULL;
	int ret;

	mapped_length = extent_len;
	ret = btrfs_map_block(fs_info, READ, extent_logical,
			      &mapped_length, &bbio, 0);
	if (ret || !bbio || mapped_length < extent_len ||
	    !bbio->stripes[0].dev->bdev) {
		kfree(bbio);
		return;
	}

	*extent_physical = bbio->stripes[0].physical;
	*extent_mirror_num = bbio->mirror_num;
	*extent_dev = bbio->stripes[0].dev;
	kfree(bbio);
}

static int scrub_setup_wr_ctx(struct scrub_ctx *sctx,
			      struct scrub_wr_ctx *wr_ctx,
			      struct btrfs_fs_info *fs_info,
			      struct btrfs_device *dev,
			      int is_dev_replace)
{
	WARN_ON(wr_ctx->wr_curr_bio != NULL);

	mutex_init(&wr_ctx->wr_lock);
	wr_ctx->wr_curr_bio = NULL;
	if (!is_dev_replace)
		return 0;

	WARN_ON(!dev->bdev);
	wr_ctx->pages_per_wr_bio = min_t(int, SCRUB_PAGES_PER_WR_BIO,
					 bio_get_nr_vecs(dev->bdev));
	wr_ctx->tgtdev = dev;
	atomic_set(&wr_ctx->flush_all_writes, 0);
	return 0;
}

static void scrub_free_wr_ctx(struct scrub_wr_ctx *wr_ctx)
{
	mutex_lock(&wr_ctx->wr_lock);
	kfree(wr_ctx->wr_curr_bio);
	wr_ctx->wr_curr_bio = NULL;
	mutex_unlock(&wr_ctx->wr_lock);
}

static int copy_nocow_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
			    int mirror_num, u64 physical_for_dev_replace)
{
	struct scrub_copy_nocow_ctx *nocow_ctx;
	struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;

	nocow_ctx = kzalloc(sizeof(*nocow_ctx), GFP_NOFS);
	if (!nocow_ctx) {
		spin_lock(&sctx->stat_lock);
		sctx->stat.malloc_errors++;
		spin_unlock(&sctx->stat_lock);
		return -ENOMEM;
	}

	scrub_pending_trans_workers_inc(sctx);

	nocow_ctx->sctx = sctx;
	nocow_ctx->logical = logical;
	nocow_ctx->len = len;
	nocow_ctx->mirror_num = mirror_num;
	nocow_ctx->physical_for_dev_replace = physical_for_dev_replace;
	nocow_ctx->work.func = copy_nocow_pages_worker;
	btrfs_queue_worker(&fs_info->scrub_nocow_workers,
			   &nocow_ctx->work);

	return 0;
}

static void copy_nocow_pages_worker(struct btrfs_work *work)
{
	struct scrub_copy_nocow_ctx *nocow_ctx =
		container_of(work, struct scrub_copy_nocow_ctx, work);
	struct scrub_ctx *sctx = nocow_ctx->sctx;
	u64 logical = nocow_ctx->logical;
	u64 len = nocow_ctx->len;
	int mirror_num = nocow_ctx->mirror_num;
	u64 physical_for_dev_replace = nocow_ctx->physical_for_dev_replace;
	int ret;
	struct btrfs_trans_handle *trans = NULL;
	struct btrfs_fs_info *fs_info;
	struct btrfs_path *path;
	struct btrfs_root *root;
	int not_written = 0;

	fs_info = sctx->dev_root->fs_info;
	root = fs_info->extent_root;

	path = btrfs_alloc_path();
	if (!path) {
		spin_lock(&sctx->stat_lock);
		sctx->stat.malloc_errors++;
		spin_unlock(&sctx->stat_lock);
		not_written = 1;
		goto out;
	}

	trans = btrfs_join_transaction(root);
	if (IS_ERR(trans)) {
		not_written = 1;
		goto out;
	}

	ret = iterate_inodes_from_logical(logical, fs_info, path,
					  copy_nocow_pages_for_inode,
					  nocow_ctx);
	if (ret != 0 && ret != -ENOENT) {
		pr_warn("iterate_inodes_from_logical() failed: log %llu, phys %llu, len %llu, mir %llu, ret %d\n",
3174
			logical, physical_for_dev_replace, len,
3175 3176 3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188 3189 3190 3191 3192 3193 3194 3195
			(unsigned long long)mirror_num, ret);
		not_written = 1;
		goto out;
	}

out:
	if (trans && !IS_ERR(trans))
		btrfs_end_transaction(trans, root);
	if (not_written)
		btrfs_dev_replace_stats_inc(&fs_info->dev_replace.
					    num_uncorrectable_read_errors);

	btrfs_free_path(path);
	kfree(nocow_ctx);

	scrub_pending_trans_workers_dec(sctx);
}

static int copy_nocow_pages_for_inode(u64 inum, u64 offset, u64 root, void *ctx)
{
	struct scrub_copy_nocow_ctx *nocow_ctx = ctx;
3196
	struct btrfs_fs_info *fs_info = nocow_ctx->sctx->dev_root->fs_info;
3197
	struct btrfs_key key;
3198 3199
	struct inode *inode;
	struct page *page;
3200 3201 3202
	struct btrfs_root *local_root;
	u64 physical_for_dev_replace;
	u64 len;
3203
	unsigned long index;
3204
	int srcu_index;
3205 3206
	int ret;
	int err;
3207 3208 3209 3210

	key.objectid = root;
	key.type = BTRFS_ROOT_ITEM_KEY;
	key.offset = (u64)-1;
3211 3212 3213

	srcu_index = srcu_read_lock(&fs_info->subvol_srcu);

3214
	local_root = btrfs_read_fs_root_no_name(fs_info, &key);
3215 3216
	if (IS_ERR(local_root)) {
		srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
3217
		return PTR_ERR(local_root);
3218
	}
3219

3220 3221 3222 3223 3224
	if (btrfs_root_refs(&local_root->root_item) == 0) {
		srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
		return -ENOENT;
	}

3225 3226 3227 3228
	key.type = BTRFS_INODE_ITEM_KEY;
	key.objectid = inum;
	key.offset = 0;
	inode = btrfs_iget(fs_info->sb, &key, local_root, NULL);
3229
	srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
3230 3231 3232
	if (IS_ERR(inode))
		return PTR_ERR(inode);

3233 3234 3235 3236
	/* Avoid truncate/dio/punch hole.. */
	mutex_lock(&inode->i_mutex);
	inode_dio_wait(inode);

3237
	ret = 0;
3238 3239 3240 3241
	physical_for_dev_replace = nocow_ctx->physical_for_dev_replace;
	len = nocow_ctx->len;
	while (len >= PAGE_CACHE_SIZE) {
		index = offset >> PAGE_CACHE_SHIFT;
3242
again:
3243 3244 3245 3246
		page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
		if (!page) {
			pr_err("find_or_create_page() failed\n");
			ret = -ENOMEM;
3247
			goto out;
3248 3249 3250 3251 3252 3253 3254
		}

		if (PageUptodate(page)) {
			if (PageDirty(page))
				goto next_page;
		} else {
			ClearPageError(page);
3255
			err = extent_read_full_page(&BTRFS_I(inode)->
3256 3257 3258
							 io_tree,
							page, btrfs_get_extent,
							nocow_ctx->mirror_num);
3259 3260
			if (err) {
				ret = err;
3261 3262
				goto next_page;
			}
3263

3264
			lock_page(page);
3265 3266 3267 3268 3269 3270 3271 3272 3273 3274
			/*
			 * If the page has been remove from the page cache,
			 * the data on it is meaningless, because it may be
			 * old one, the new data may be written into the new
			 * page in the page cache.
			 */
			if (page->mapping != inode->i_mapping) {
				page_cache_release(page);
				goto again;
			}
3275 3276 3277 3278 3279
			if (!PageUptodate(page)) {
				ret = -EIO;
				goto next_page;
			}
		}
3280 3281 3282 3283
		err = write_page_nocow(nocow_ctx->sctx,
				       physical_for_dev_replace, page);
		if (err)
			ret = err;
3284
next_page:
3285 3286 3287 3288 3289 3290
		unlock_page(page);
		page_cache_release(page);

		if (ret)
			break;

3291 3292 3293 3294
		offset += PAGE_CACHE_SIZE;
		physical_for_dev_replace += PAGE_CACHE_SIZE;
		len -= PAGE_CACHE_SIZE;
	}
3295
out:
3296
	mutex_unlock(&inode->i_mutex);
3297
	iput(inode);
3298 3299 3300 3301 3302 3303 3304 3305 3306 3307 3308 3309 3310 3311 3312 3313 3314 3315 3316
	return ret;
}

static int write_page_nocow(struct scrub_ctx *sctx,
			    u64 physical_for_dev_replace, struct page *page)
{
	struct bio *bio;
	struct btrfs_device *dev;
	int ret;
	DECLARE_COMPLETION_ONSTACK(compl);

	dev = sctx->wr_ctx.tgtdev;
	if (!dev)
		return -EIO;
	if (!dev->bdev) {
		printk_ratelimited(KERN_WARNING
			"btrfs: scrub write_page_nocow(bdev == NULL) is unexpected!\n");
		return -EIO;
	}
3317
	bio = btrfs_io_bio_alloc(GFP_NOFS, 1);
3318 3319 3320 3321 3322 3323 3324 3325 3326 3327 3328 3329 3330 3331 3332 3333 3334 3335 3336 3337 3338 3339 3340 3341 3342 3343 3344
	if (!bio) {
		spin_lock(&sctx->stat_lock);
		sctx->stat.malloc_errors++;
		spin_unlock(&sctx->stat_lock);
		return -ENOMEM;
	}
	bio->bi_private = &compl;
	bio->bi_end_io = scrub_complete_bio_end_io;
	bio->bi_size = 0;
	bio->bi_sector = physical_for_dev_replace >> 9;
	bio->bi_bdev = dev->bdev;
	ret = bio_add_page(bio, page, PAGE_CACHE_SIZE, 0);
	if (ret != PAGE_CACHE_SIZE) {
leave_with_eio:
		bio_put(bio);
		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
		return -EIO;
	}
	btrfsic_submit_bio(WRITE_SYNC, bio);
	wait_for_completion(&compl);

	if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
		goto leave_with_eio;

	bio_put(bio);
	return 0;
}