scrub.c 88.4 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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/*
 * 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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	btrfs_release_path(path);
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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),
555 556 557 558 559 560 561
				(unsigned long long)swarn.sector,
				ref_level ? "node" : "leaf",
				ret < 0 ? -1 : ref_level,
				ret < 0 ? -1 : ref_root);
		} while (ret != 1);
	} else {
		swarn.path = path;
562
		swarn.dev = dev;
563 564
		iterate_extent_inodes(fs_info, found_key.objectid,
					extent_item_pos, 1,
565 566 567 568 569 570 571 572 573
					scrub_print_warning_inode, &swarn);
	}

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

574
static int scrub_fixup_readpage(u64 inum, u64 offset, u64 root, void *fixup_ctx)
575
{
576
	struct page *page = NULL;
577
	unsigned long index;
578
	struct scrub_fixup_nodatasum *fixup = fixup_ctx;
579
	int ret;
580
	int corrected = 0;
581
	struct btrfs_key key;
582
	struct inode *inode = NULL;
583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602
	u64 end = offset + PAGE_SIZE - 1;
	struct btrfs_root *local_root;

	key.objectid = root;
	key.type = BTRFS_ROOT_ITEM_KEY;
	key.offset = (u64)-1;
	local_root = btrfs_read_fs_root_no_name(fixup->root->fs_info, &key);
	if (IS_ERR(local_root))
		return PTR_ERR(local_root);

	key.type = BTRFS_INODE_ITEM_KEY;
	key.objectid = inum;
	key.offset = 0;
	inode = btrfs_iget(fixup->root->fs_info->sb, &key, local_root, NULL);
	if (IS_ERR(inode))
		return PTR_ERR(inode);

	index = offset >> PAGE_CACHE_SHIFT;

	page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
603 604 605 606 607 608
	if (!page) {
		ret = -ENOMEM;
		goto out;
	}

	if (PageUptodate(page)) {
609
		struct btrfs_fs_info *fs_info;
610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629
		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;
		}
630 631
		fs_info = BTRFS_I(inode)->root->fs_info;
		ret = repair_io_failure(fs_info, offset, PAGE_SIZE,
632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668
					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);
669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687

	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;
688
	struct scrub_ctx *sctx;
689 690 691 692 693 694
	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);
695
	sctx = fixup->sctx;
696 697 698 699
	fs_info = fixup->root->fs_info;

	path = btrfs_alloc_path();
	if (!path) {
700 701 702
		spin_lock(&sctx->stat_lock);
		++sctx->stat.malloc_errors;
		spin_unlock(&sctx->stat_lock);
703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730
		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);

731 732 733
	spin_lock(&sctx->stat_lock);
	++sctx->stat.corrected_errors;
	spin_unlock(&sctx->stat_lock);
734 735 736 737 738

out:
	if (trans && !IS_ERR(trans))
		btrfs_end_transaction(trans, fixup->root);
	if (uncorrectable) {
739 740 741
		spin_lock(&sctx->stat_lock);
		++sctx->stat.uncorrectable_errors;
		spin_unlock(&sctx->stat_lock);
742 743 744
		btrfs_dev_replace_stats_inc(
			&sctx->dev_root->fs_info->dev_replace.
			num_uncorrectable_read_errors);
745
		printk_ratelimited_in_rcu(KERN_ERR
746
			"btrfs: unable to fixup (nodatasum) error at logical %llu on dev %s\n",
747
			(unsigned long long)fixup->logical,
748
			rcu_str_deref(fixup->dev->name));
749 750 751 752 753
	}

	btrfs_free_path(path);
	kfree(fixup);

754
	scrub_pending_trans_workers_dec(sctx);
755 756
}

A
Arne Jansen 已提交
757
/*
758 759 760 761 762 763
 * 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
764
 */
765
static int scrub_handle_errored_block(struct scrub_block *sblock_to_check)
A
Arne Jansen 已提交
766
{
767
	struct scrub_ctx *sctx = sblock_to_check->sctx;
768
	struct btrfs_device *dev;
769 770 771 772 773 774 775 776 777 778 779 780 781 782
	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;
783
	static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
784 785 786
				      DEFAULT_RATELIMIT_BURST);

	BUG_ON(sblock_to_check->page_count < 1);
787
	fs_info = sctx->dev_root->fs_info;
788
	length = sblock_to_check->page_count * PAGE_SIZE;
789 790 791 792 793
	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 &
794
			BTRFS_EXTENT_FLAG_DATA);
795 796 797
	have_csum = sblock_to_check->pagev[0]->have_csum;
	csum = sblock_to_check->pagev[0]->csum;
	dev = sblock_to_check->pagev[0]->dev;
798

799 800 801 802 803
	if (sctx->is_dev_replace && !is_metadata && !have_csum) {
		sblocks_for_recheck = NULL;
		goto nodatasum_case;
	}

804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836
	/*
	 * 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) {
837 838 839 840 841
		spin_lock(&sctx->stat_lock);
		sctx->stat.malloc_errors++;
		sctx->stat.read_errors++;
		sctx->stat.uncorrectable_errors++;
		spin_unlock(&sctx->stat_lock);
842
		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
843
		goto out;
A
Arne Jansen 已提交
844 845
	}

846
	/* setup the context, map the logical blocks and alloc the pages */
847
	ret = scrub_setup_recheck_block(sctx, fs_info, sblock_to_check, length,
848 849
					logical, sblocks_for_recheck);
	if (ret) {
850 851 852 853
		spin_lock(&sctx->stat_lock);
		sctx->stat.read_errors++;
		sctx->stat.uncorrectable_errors++;
		spin_unlock(&sctx->stat_lock);
854
		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
855 856 857 858
		goto out;
	}
	BUG_ON(failed_mirror_index >= BTRFS_MAX_MIRRORS);
	sblock_bad = sblocks_for_recheck + failed_mirror_index;
859

860
	/* build and submit the bios for the failed mirror, check checksums */
861 862
	scrub_recheck_block(fs_info, sblock_bad, is_metadata, have_csum,
			    csum, generation, sctx->csum_size);
A
Arne Jansen 已提交
863

864 865 866 867 868 869 870 871 872 873
	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)
		 */
874 875 876
		spin_lock(&sctx->stat_lock);
		sctx->stat.unverified_errors++;
		spin_unlock(&sctx->stat_lock);
A
Arne Jansen 已提交
877

878 879
		if (sctx->is_dev_replace)
			scrub_write_block_to_dev_replace(sblock_bad);
880
		goto out;
A
Arne Jansen 已提交
881 882
	}

883
	if (!sblock_bad->no_io_error_seen) {
884 885 886
		spin_lock(&sctx->stat_lock);
		sctx->stat.read_errors++;
		spin_unlock(&sctx->stat_lock);
887 888
		if (__ratelimit(&_rs))
			scrub_print_warning("i/o error", sblock_to_check);
889
		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
890
	} else if (sblock_bad->checksum_error) {
891 892 893
		spin_lock(&sctx->stat_lock);
		sctx->stat.csum_errors++;
		spin_unlock(&sctx->stat_lock);
894 895
		if (__ratelimit(&_rs))
			scrub_print_warning("checksum error", sblock_to_check);
896
		btrfs_dev_stat_inc_and_print(dev,
897
					     BTRFS_DEV_STAT_CORRUPTION_ERRS);
898
	} else if (sblock_bad->header_error) {
899 900 901
		spin_lock(&sctx->stat_lock);
		sctx->stat.verify_errors++;
		spin_unlock(&sctx->stat_lock);
902 903 904
		if (__ratelimit(&_rs))
			scrub_print_warning("checksum/header error",
					    sblock_to_check);
905
		if (sblock_bad->generation_error)
906
			btrfs_dev_stat_inc_and_print(dev,
907 908
				BTRFS_DEV_STAT_GENERATION_ERRS);
		else
909
			btrfs_dev_stat_inc_and_print(dev,
910
				BTRFS_DEV_STAT_CORRUPTION_ERRS);
911
	}
A
Arne Jansen 已提交
912

913
	if (sctx->readonly && !sctx->is_dev_replace)
914
		goto did_not_correct_error;
A
Arne Jansen 已提交
915

916 917
	if (!is_metadata && !have_csum) {
		struct scrub_fixup_nodatasum *fixup_nodatasum;
A
Arne Jansen 已提交
918

919 920 921
nodatasum_case:
		WARN_ON(sctx->is_dev_replace);

922 923 924 925 926 927 928 929 930 931
		/*
		 * !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;
932
		fixup_nodatasum->sctx = sctx;
933
		fixup_nodatasum->dev = dev;
934 935 936
		fixup_nodatasum->logical = logical;
		fixup_nodatasum->root = fs_info->extent_root;
		fixup_nodatasum->mirror_num = failed_mirror_index + 1;
937
		scrub_pending_trans_workers_inc(sctx);
938 939 940 941
		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
942 943
	}

944 945
	/*
	 * now build and submit the bios for the other mirrors, check
946 947
	 * checksums.
	 * First try to pick the mirror which is completely without I/O
948 949 950 951 952 953 954 955 956 957 958 959 960 961 962
	 * 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++) {
963
		struct scrub_block *sblock_other;
964

965 966 967 968 969
		if (mirror_index == failed_mirror_index)
			continue;
		sblock_other = sblocks_for_recheck + mirror_index;

		/* build and submit the bios, check checksums */
970 971 972 973 974
		scrub_recheck_block(fs_info, sblock_other, is_metadata,
				    have_csum, csum, generation,
				    sctx->csum_size);

		if (!sblock_other->header_error &&
975 976
		    !sblock_other->checksum_error &&
		    sblock_other->no_io_error_seen) {
977 978 979 980 981 982 983 984 985
			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);
			}
986 987 988 989
			if (0 == ret)
				goto corrected_error;
		}
	}
A
Arne Jansen 已提交
990 991

	/*
992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 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
	 * 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
1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070
	 * 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
1071 1072
	 */

1073 1074 1075 1076 1077 1078
	/* 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++) {
1079
		struct scrub_page *page_bad = sblock_bad->pagev[page_num];
1080 1081

		if (!page_bad->io_error)
A
Arne Jansen 已提交
1082
			continue;
1083 1084 1085 1086 1087 1088 1089

		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;
1090 1091
			struct scrub_page *page_other = sblock_other->pagev[
							page_num];
1092 1093 1094 1095 1096 1097 1098 1099 1100

			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
1101
		}
A
Arne Jansen 已提交
1102

1103 1104 1105 1106
		if (page_bad->io_error) {
			/* did not find a mirror to copy the page from */
			success = 0;
		}
A
Arne Jansen 已提交
1107 1108
	}

1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119
	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.
			 */
1120 1121 1122 1123
			scrub_recheck_block(fs_info, sblock_bad,
					    is_metadata, have_csum, csum,
					    generation, sctx->csum_size);
			if (!sblock_bad->header_error &&
1124 1125 1126 1127 1128 1129 1130
			    !sblock_bad->checksum_error &&
			    sblock_bad->no_io_error_seen)
				goto corrected_error;
			else
				goto did_not_correct_error;
		} else {
corrected_error:
1131 1132 1133
			spin_lock(&sctx->stat_lock);
			sctx->stat.corrected_errors++;
			spin_unlock(&sctx->stat_lock);
1134
			printk_ratelimited_in_rcu(KERN_ERR
1135
				"btrfs: fixed up error at logical %llu on dev %s\n",
1136
				(unsigned long long)logical,
1137
				rcu_str_deref(dev->name));
A
Arne Jansen 已提交
1138
		}
1139 1140
	} else {
did_not_correct_error:
1141 1142 1143
		spin_lock(&sctx->stat_lock);
		sctx->stat.uncorrectable_errors++;
		spin_unlock(&sctx->stat_lock);
1144
		printk_ratelimited_in_rcu(KERN_ERR
1145
			"btrfs: unable to fixup (regular) error at logical %llu on dev %s\n",
1146
			(unsigned long long)logical,
1147
			rcu_str_deref(dev->name));
I
Ilya Dryomov 已提交
1148
	}
A
Arne Jansen 已提交
1149

1150 1151 1152 1153 1154 1155 1156 1157
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;

1158 1159 1160 1161 1162
			for (page_index = 0; page_index < sblock->page_count;
			     page_index++) {
				sblock->pagev[page_index]->sblock = NULL;
				scrub_page_put(sblock->pagev[page_index]);
			}
1163 1164 1165
		}
		kfree(sblocks_for_recheck);
	}
A
Arne Jansen 已提交
1166

1167 1168
	return 0;
}
A
Arne Jansen 已提交
1169

1170
static int scrub_setup_recheck_block(struct scrub_ctx *sctx,
1171
				     struct btrfs_fs_info *fs_info,
1172
				     struct scrub_block *original_sblock,
1173 1174 1175 1176 1177 1178 1179 1180
				     u64 length, u64 logical,
				     struct scrub_block *sblocks_for_recheck)
{
	int page_index;
	int mirror_index;
	int ret;

	/*
1181
	 * note: the two members ref_count and outstanding_pages
1182 1183 1184 1185 1186 1187 1188 1189 1190
	 * 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
1191

1192 1193 1194 1195
		/*
		 * with a length of PAGE_SIZE, each returned stripe
		 * represents one mirror
		 */
1196 1197
		ret = btrfs_map_block(fs_info, REQ_GET_READ_MIRRORS, logical,
				      &mapped_length, &bbio, 0);
1198 1199 1200 1201
		if (ret || !bbio || mapped_length < sublen) {
			kfree(bbio);
			return -EIO;
		}
A
Arne Jansen 已提交
1202

1203
		BUG_ON(page_index >= SCRUB_PAGES_PER_RD_BIO);
1204 1205 1206 1207 1208 1209 1210 1211 1212
		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;
1213 1214 1215 1216
			sblock->sctx = sctx;
			page = kzalloc(sizeof(*page), GFP_NOFS);
			if (!page) {
leave_nomem:
1217 1218 1219
				spin_lock(&sctx->stat_lock);
				sctx->stat.malloc_errors++;
				spin_unlock(&sctx->stat_lock);
1220
				kfree(bbio);
1221 1222
				return -ENOMEM;
			}
1223 1224 1225 1226
			scrub_page_get(page);
			sblock->pagev[page_index] = page;
			page->logical = logical;
			page->physical = bbio->stripes[mirror_index].physical;
1227 1228 1229 1230
			BUG_ON(page_index >= original_sblock->page_count);
			page->physical_for_dev_replace =
				original_sblock->pagev[page_index]->
				physical_for_dev_replace;
1231 1232 1233
			/* for missing devices, dev->bdev is NULL */
			page->dev = bbio->stripes[mirror_index].dev;
			page->mirror_num = mirror_index + 1;
1234
			sblock->page_count++;
1235 1236 1237
			page->page = alloc_page(GFP_NOFS);
			if (!page->page)
				goto leave_nomem;
1238 1239 1240 1241 1242 1243 1244 1245
		}
		kfree(bbio);
		length -= sublen;
		logical += sublen;
		page_index++;
	}

	return 0;
I
Ilya Dryomov 已提交
1246 1247
}

1248 1249 1250 1251 1252 1253 1254
/*
 * 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.
 */
1255 1256 1257 1258
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
1259
{
1260
	int page_num;
I
Ilya Dryomov 已提交
1261

1262 1263 1264
	sblock->no_io_error_seen = 1;
	sblock->header_error = 0;
	sblock->checksum_error = 0;
I
Ilya Dryomov 已提交
1265

1266 1267
	for (page_num = 0; page_num < sblock->page_count; page_num++) {
		struct bio *bio;
1268
		struct scrub_page *page = sblock->pagev[page_num];
1269 1270
		DECLARE_COMPLETION_ONSTACK(complete);

1271
		if (page->dev->bdev == NULL) {
1272 1273 1274 1275 1276
			page->io_error = 1;
			sblock->no_io_error_seen = 0;
			continue;
		}

1277
		WARN_ON(!page->page);
1278
		bio = bio_alloc(GFP_NOFS, 1);
1279 1280 1281 1282 1283
		if (!bio) {
			page->io_error = 1;
			sblock->no_io_error_seen = 0;
			continue;
		}
1284
		bio->bi_bdev = page->dev->bdev;
1285 1286 1287 1288
		bio->bi_sector = page->physical >> 9;
		bio->bi_end_io = scrub_complete_bio_end_io;
		bio->bi_private = &complete;

1289
		bio_add_page(bio, page->page, PAGE_SIZE, 0);
1290
		btrfsic_submit_bio(READ, bio);
I
Ilya Dryomov 已提交
1291

1292 1293
		/* this will also unplug the queue */
		wait_for_completion(&complete);
I
Ilya Dryomov 已提交
1294

1295 1296 1297 1298 1299
		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
1300

1301 1302 1303 1304 1305
	if (sblock->no_io_error_seen)
		scrub_recheck_block_checksum(fs_info, sblock, is_metadata,
					     have_csum, csum, generation,
					     csum_size);

1306
	return;
A
Arne Jansen 已提交
1307 1308
}

1309 1310 1311 1312 1313
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
1314
{
1315 1316 1317 1318 1319 1320
	int page_num;
	u8 calculated_csum[BTRFS_CSUM_SIZE];
	u32 crc = ~(u32)0;
	struct btrfs_root *root = fs_info->extent_root;
	void *mapped_buffer;

1321
	WARN_ON(!sblock->pagev[0]->page);
1322 1323 1324
	if (is_metadata) {
		struct btrfs_header *h;

1325
		mapped_buffer = kmap_atomic(sblock->pagev[0]->page);
1326 1327
		h = (struct btrfs_header *)mapped_buffer;

1328
		if (sblock->pagev[0]->logical != le64_to_cpu(h->bytenr) ||
1329 1330
		    memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE) ||
		    memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
1331
			   BTRFS_UUID_SIZE)) {
1332
			sblock->header_error = 1;
1333 1334 1335 1336
		} else if (generation != le64_to_cpu(h->generation)) {
			sblock->header_error = 1;
			sblock->generation_error = 1;
		}
1337 1338 1339 1340
		csum = h->csum;
	} else {
		if (!have_csum)
			return;
A
Arne Jansen 已提交
1341

1342
		mapped_buffer = kmap_atomic(sblock->pagev[0]->page);
1343
	}
A
Arne Jansen 已提交
1344

1345 1346 1347 1348 1349 1350 1351 1352 1353
	for (page_num = 0;;) {
		if (page_num == 0 && is_metadata)
			crc = btrfs_csum_data(root,
				((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE,
				crc, PAGE_SIZE - BTRFS_CSUM_SIZE);
		else
			crc = btrfs_csum_data(root, mapped_buffer, crc,
					      PAGE_SIZE);

1354
		kunmap_atomic(mapped_buffer);
1355 1356 1357
		page_num++;
		if (page_num >= sblock->page_count)
			break;
1358
		WARN_ON(!sblock->pagev[page_num]->page);
1359

1360
		mapped_buffer = kmap_atomic(sblock->pagev[page_num]->page);
1361 1362 1363 1364 1365
	}

	btrfs_csum_final(crc, calculated_csum);
	if (memcmp(calculated_csum, csum, csum_size))
		sblock->checksum_error = 1;
A
Arne Jansen 已提交
1366 1367
}

1368
static void scrub_complete_bio_end_io(struct bio *bio, int err)
A
Arne Jansen 已提交
1369
{
1370 1371
	complete((struct completion *)bio->bi_private);
}
A
Arne Jansen 已提交
1372

1373 1374 1375 1376 1377 1378
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
1379

1380 1381
	for (page_num = 0; page_num < sblock_bad->page_count; page_num++) {
		int ret_sub;
I
Ilya Dryomov 已提交
1382

1383 1384 1385 1386 1387 1388
		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
1389
	}
1390 1391 1392 1393 1394 1395 1396 1397

	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)
{
1398 1399
	struct scrub_page *page_bad = sblock_bad->pagev[page_num];
	struct scrub_page *page_good = sblock_good->pagev[page_num];
1400

1401 1402
	BUG_ON(page_bad->page == NULL);
	BUG_ON(page_good->page == NULL);
1403 1404 1405 1406 1407 1408
	if (force_write || sblock_bad->header_error ||
	    sblock_bad->checksum_error || page_bad->io_error) {
		struct bio *bio;
		int ret;
		DECLARE_COMPLETION_ONSTACK(complete);

1409 1410 1411 1412 1413 1414
		if (!page_bad->dev->bdev) {
			printk_ratelimited(KERN_WARNING
				"btrfs: scrub_repair_page_from_good_copy(bdev == NULL) is unexpected!\n");
			return -EIO;
		}

1415
		bio = bio_alloc(GFP_NOFS, 1);
1416 1417
		if (!bio)
			return -EIO;
1418
		bio->bi_bdev = page_bad->dev->bdev;
1419 1420 1421 1422 1423 1424 1425 1426
		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;
1427
		}
1428 1429 1430 1431
		btrfsic_submit_bio(WRITE, bio);

		/* this will also unplug the queue */
		wait_for_completion(&complete);
1432 1433 1434
		if (!bio_flagged(bio, BIO_UPTODATE)) {
			btrfs_dev_stat_inc_and_print(page_bad->dev,
				BTRFS_DEV_STAT_WRITE_ERRS);
1435 1436 1437
			btrfs_dev_replace_stats_inc(
				&sblock_bad->sctx->dev_root->fs_info->
				dev_replace.num_write_errors);
1438 1439 1440
			bio_put(bio);
			return -EIO;
		}
1441
		bio_put(bio);
A
Arne Jansen 已提交
1442 1443
	}

1444 1445 1446
	return 0;
}

1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 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 1522 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
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) {
			bio = bio_alloc(GFP_NOFS, wr_ctx->pages_per_wr_bio);
			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)
1609 1610 1611 1612
{
	u64 flags;
	int ret;

1613 1614
	WARN_ON(sblock->page_count < 1);
	flags = sblock->pagev[0]->flags;
1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625
	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);
1626 1627

	return ret;
A
Arne Jansen 已提交
1628 1629
}

1630
static int scrub_checksum_data(struct scrub_block *sblock)
A
Arne Jansen 已提交
1631
{
1632
	struct scrub_ctx *sctx = sblock->sctx;
A
Arne Jansen 已提交
1633
	u8 csum[BTRFS_CSUM_SIZE];
1634 1635 1636
	u8 *on_disk_csum;
	struct page *page;
	void *buffer;
A
Arne Jansen 已提交
1637 1638
	u32 crc = ~(u32)0;
	int fail = 0;
1639
	struct btrfs_root *root = sctx->dev_root;
1640 1641
	u64 len;
	int index;
A
Arne Jansen 已提交
1642

1643
	BUG_ON(sblock->page_count < 1);
1644
	if (!sblock->pagev[0]->have_csum)
A
Arne Jansen 已提交
1645 1646
		return 0;

1647 1648
	on_disk_csum = sblock->pagev[0]->csum;
	page = sblock->pagev[0]->page;
1649
	buffer = kmap_atomic(page);
1650

1651
	len = sctx->sectorsize;
1652 1653 1654 1655 1656
	index = 0;
	for (;;) {
		u64 l = min_t(u64, len, PAGE_SIZE);

		crc = btrfs_csum_data(root, buffer, crc, l);
1657
		kunmap_atomic(buffer);
1658 1659 1660 1661 1662
		len -= l;
		if (len == 0)
			break;
		index++;
		BUG_ON(index >= sblock->page_count);
1663 1664
		BUG_ON(!sblock->pagev[index]->page);
		page = sblock->pagev[index]->page;
1665
		buffer = kmap_atomic(page);
1666 1667
	}

A
Arne Jansen 已提交
1668
	btrfs_csum_final(crc, csum);
1669
	if (memcmp(csum, on_disk_csum, sctx->csum_size))
A
Arne Jansen 已提交
1670 1671 1672 1673 1674
		fail = 1;

	return fail;
}

1675
static int scrub_checksum_tree_block(struct scrub_block *sblock)
A
Arne Jansen 已提交
1676
{
1677
	struct scrub_ctx *sctx = sblock->sctx;
A
Arne Jansen 已提交
1678
	struct btrfs_header *h;
1679
	struct btrfs_root *root = sctx->dev_root;
A
Arne Jansen 已提交
1680
	struct btrfs_fs_info *fs_info = root->fs_info;
1681 1682 1683 1684 1685 1686
	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
1687 1688 1689
	u32 crc = ~(u32)0;
	int fail = 0;
	int crc_fail = 0;
1690 1691 1692 1693
	u64 len;
	int index;

	BUG_ON(sblock->page_count < 1);
1694
	page = sblock->pagev[0]->page;
1695
	mapped_buffer = kmap_atomic(page);
1696
	h = (struct btrfs_header *)mapped_buffer;
1697
	memcpy(on_disk_csum, h->csum, sctx->csum_size);
A
Arne Jansen 已提交
1698 1699 1700 1701 1702 1703 1704

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

1705
	if (sblock->pagev[0]->logical != le64_to_cpu(h->bytenr))
A
Arne Jansen 已提交
1706 1707
		++fail;

1708
	if (sblock->pagev[0]->generation != le64_to_cpu(h->generation))
A
Arne Jansen 已提交
1709 1710 1711 1712 1713 1714 1715 1716 1717
		++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;

1718
	WARN_ON(sctx->nodesize != sctx->leafsize);
1719
	len = sctx->nodesize - BTRFS_CSUM_SIZE;
1720 1721 1722 1723 1724 1725 1726
	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);

		crc = btrfs_csum_data(root, p, crc, l);
1727
		kunmap_atomic(mapped_buffer);
1728 1729 1730 1731 1732
		len -= l;
		if (len == 0)
			break;
		index++;
		BUG_ON(index >= sblock->page_count);
1733 1734
		BUG_ON(!sblock->pagev[index]->page);
		page = sblock->pagev[index]->page;
1735
		mapped_buffer = kmap_atomic(page);
1736 1737 1738 1739 1740
		mapped_size = PAGE_SIZE;
		p = mapped_buffer;
	}

	btrfs_csum_final(crc, calculated_csum);
1741
	if (memcmp(calculated_csum, on_disk_csum, sctx->csum_size))
A
Arne Jansen 已提交
1742 1743 1744 1745 1746
		++crc_fail;

	return fail || crc_fail;
}

1747
static int scrub_checksum_super(struct scrub_block *sblock)
A
Arne Jansen 已提交
1748 1749
{
	struct btrfs_super_block *s;
1750
	struct scrub_ctx *sctx = sblock->sctx;
1751
	struct btrfs_root *root = sctx->dev_root;
A
Arne Jansen 已提交
1752
	struct btrfs_fs_info *fs_info = root->fs_info;
1753 1754 1755 1756 1757 1758
	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
1759
	u32 crc = ~(u32)0;
1760 1761
	int fail_gen = 0;
	int fail_cor = 0;
1762 1763
	u64 len;
	int index;
A
Arne Jansen 已提交
1764

1765
	BUG_ON(sblock->page_count < 1);
1766
	page = sblock->pagev[0]->page;
1767
	mapped_buffer = kmap_atomic(page);
1768
	s = (struct btrfs_super_block *)mapped_buffer;
1769
	memcpy(on_disk_csum, s->csum, sctx->csum_size);
A
Arne Jansen 已提交
1770

1771
	if (sblock->pagev[0]->logical != le64_to_cpu(s->bytenr))
1772
		++fail_cor;
A
Arne Jansen 已提交
1773

1774
	if (sblock->pagev[0]->generation != le64_to_cpu(s->generation))
1775
		++fail_gen;
A
Arne Jansen 已提交
1776 1777

	if (memcmp(s->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
1778
		++fail_cor;
A
Arne Jansen 已提交
1779

1780 1781 1782 1783 1784 1785 1786 1787
	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);

		crc = btrfs_csum_data(root, p, crc, l);
1788
		kunmap_atomic(mapped_buffer);
1789 1790 1791 1792 1793
		len -= l;
		if (len == 0)
			break;
		index++;
		BUG_ON(index >= sblock->page_count);
1794 1795
		BUG_ON(!sblock->pagev[index]->page);
		page = sblock->pagev[index]->page;
1796
		mapped_buffer = kmap_atomic(page);
1797 1798 1799 1800 1801
		mapped_size = PAGE_SIZE;
		p = mapped_buffer;
	}

	btrfs_csum_final(crc, calculated_csum);
1802
	if (memcmp(calculated_csum, on_disk_csum, sctx->csum_size))
1803
		++fail_cor;
A
Arne Jansen 已提交
1804

1805
	if (fail_cor + fail_gen) {
A
Arne Jansen 已提交
1806 1807 1808 1809 1810
		/*
		 * if we find an error in a super block, we just report it.
		 * They will get written with the next transaction commit
		 * anyway
		 */
1811 1812 1813
		spin_lock(&sctx->stat_lock);
		++sctx->stat.super_errors;
		spin_unlock(&sctx->stat_lock);
1814
		if (fail_cor)
1815
			btrfs_dev_stat_inc_and_print(sblock->pagev[0]->dev,
1816 1817
				BTRFS_DEV_STAT_CORRUPTION_ERRS);
		else
1818
			btrfs_dev_stat_inc_and_print(sblock->pagev[0]->dev,
1819
				BTRFS_DEV_STAT_GENERATION_ERRS);
A
Arne Jansen 已提交
1820 1821
	}

1822
	return fail_cor + fail_gen;
A
Arne Jansen 已提交
1823 1824
}

1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835
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++)
1836
			scrub_page_put(sblock->pagev[i]);
1837 1838 1839 1840
		kfree(sblock);
	}
}

1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854
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);
	}
}

1855
static void scrub_submit(struct scrub_ctx *sctx)
A
Arne Jansen 已提交
1856 1857 1858
{
	struct scrub_bio *sbio;

1859
	if (sctx->curr == -1)
S
Stefan Behrens 已提交
1860
		return;
A
Arne Jansen 已提交
1861

1862 1863
	sbio = sctx->bios[sctx->curr];
	sctx->curr = -1;
1864
	scrub_pending_bio_inc(sctx);
A
Arne Jansen 已提交
1865

1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879
	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
1880 1881
}

1882 1883
static int scrub_add_page_to_rd_bio(struct scrub_ctx *sctx,
				    struct scrub_page *spage)
A
Arne Jansen 已提交
1884
{
1885
	struct scrub_block *sblock = spage->sblock;
A
Arne Jansen 已提交
1886
	struct scrub_bio *sbio;
1887
	int ret;
A
Arne Jansen 已提交
1888 1889 1890 1891 1892

again:
	/*
	 * grab a fresh bio or wait for one to become available
	 */
1893 1894 1895 1896 1897 1898 1899 1900
	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
1901
		} else {
1902 1903
			spin_unlock(&sctx->list_lock);
			wait_event(sctx->list_wait, sctx->first_free != -1);
A
Arne Jansen 已提交
1904 1905
		}
	}
1906
	sbio = sctx->bios[sctx->curr];
1907
	if (sbio->page_count == 0) {
1908 1909
		struct bio *bio;

1910 1911
		sbio->physical = spage->physical;
		sbio->logical = spage->logical;
1912
		sbio->dev = spage->dev;
1913 1914
		bio = sbio->bio;
		if (!bio) {
1915
			bio = bio_alloc(GFP_NOFS, sctx->pages_per_rd_bio);
1916 1917 1918 1919
			if (!bio)
				return -ENOMEM;
			sbio->bio = bio;
		}
1920 1921 1922

		bio->bi_private = sbio;
		bio->bi_end_io = scrub_bio_end_io;
1923 1924
		bio->bi_bdev = sbio->dev->bdev;
		bio->bi_sector = sbio->physical >> 9;
1925
		sbio->err = 0;
1926 1927 1928
	} else if (sbio->physical + sbio->page_count * PAGE_SIZE !=
		   spage->physical ||
		   sbio->logical + sbio->page_count * PAGE_SIZE !=
1929 1930
		   spage->logical ||
		   sbio->dev != spage->dev) {
1931
		scrub_submit(sctx);
A
Arne Jansen 已提交
1932 1933
		goto again;
	}
1934

1935 1936 1937 1938 1939 1940 1941 1942
	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;
		}
1943
		scrub_submit(sctx);
1944 1945 1946
		goto again;
	}

1947
	scrub_block_get(sblock); /* one for the page added to the bio */
1948 1949
	atomic_inc(&sblock->outstanding_pages);
	sbio->page_count++;
1950
	if (sbio->page_count == sctx->pages_per_rd_bio)
1951
		scrub_submit(sctx);
1952 1953 1954 1955

	return 0;
}

1956
static int scrub_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
1957
		       u64 physical, struct btrfs_device *dev, u64 flags,
1958 1959
		       u64 gen, int mirror_num, u8 *csum, int force,
		       u64 physical_for_dev_replace)
1960 1961 1962 1963 1964 1965
{
	struct scrub_block *sblock;
	int index;

	sblock = kzalloc(sizeof(*sblock), GFP_NOFS);
	if (!sblock) {
1966 1967 1968
		spin_lock(&sctx->stat_lock);
		sctx->stat.malloc_errors++;
		spin_unlock(&sctx->stat_lock);
1969
		return -ENOMEM;
A
Arne Jansen 已提交
1970
	}
1971

1972 1973
	/* one ref inside this function, plus one for each page added to
	 * a bio later on */
1974
	atomic_set(&sblock->ref_count, 1);
1975
	sblock->sctx = sctx;
1976 1977 1978
	sblock->no_io_error_seen = 1;

	for (index = 0; len > 0; index++) {
1979
		struct scrub_page *spage;
1980 1981
		u64 l = min_t(u64, len, PAGE_SIZE);

1982 1983 1984
		spage = kzalloc(sizeof(*spage), GFP_NOFS);
		if (!spage) {
leave_nomem:
1985 1986 1987
			spin_lock(&sctx->stat_lock);
			sctx->stat.malloc_errors++;
			spin_unlock(&sctx->stat_lock);
1988
			scrub_block_put(sblock);
1989 1990
			return -ENOMEM;
		}
1991 1992 1993
		BUG_ON(index >= SCRUB_MAX_PAGES_PER_BLOCK);
		scrub_page_get(spage);
		sblock->pagev[index] = spage;
1994
		spage->sblock = sblock;
1995
		spage->dev = dev;
1996 1997 1998 1999
		spage->flags = flags;
		spage->generation = gen;
		spage->logical = logical;
		spage->physical = physical;
2000
		spage->physical_for_dev_replace = physical_for_dev_replace;
2001 2002 2003
		spage->mirror_num = mirror_num;
		if (csum) {
			spage->have_csum = 1;
2004
			memcpy(spage->csum, csum, sctx->csum_size);
2005 2006 2007 2008
		} else {
			spage->have_csum = 0;
		}
		sblock->page_count++;
2009 2010 2011
		spage->page = alloc_page(GFP_NOFS);
		if (!spage->page)
			goto leave_nomem;
2012 2013 2014
		len -= l;
		logical += l;
		physical += l;
2015
		physical_for_dev_replace += l;
2016 2017
	}

2018
	WARN_ON(sblock->page_count == 0);
2019
	for (index = 0; index < sblock->page_count; index++) {
2020
		struct scrub_page *spage = sblock->pagev[index];
2021 2022
		int ret;

2023
		ret = scrub_add_page_to_rd_bio(sctx, spage);
2024 2025
		if (ret) {
			scrub_block_put(sblock);
2026
			return ret;
2027
		}
2028
	}
A
Arne Jansen 已提交
2029

2030
	if (force)
2031
		scrub_submit(sctx);
A
Arne Jansen 已提交
2032

2033 2034
	/* last one frees, either here or in bio completion for last page */
	scrub_block_put(sblock);
A
Arne Jansen 已提交
2035 2036 2037
	return 0;
}

2038 2039 2040
static void scrub_bio_end_io(struct bio *bio, int err)
{
	struct scrub_bio *sbio = bio->bi_private;
2041
	struct btrfs_fs_info *fs_info = sbio->dev->dev_root->fs_info;
2042 2043 2044 2045 2046 2047 2048 2049 2050 2051

	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);
2052
	struct scrub_ctx *sctx = sbio->sctx;
2053 2054
	int i;

2055
	BUG_ON(sbio->page_count > SCRUB_PAGES_PER_RD_BIO);
2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076
	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;
2077 2078 2079 2080
	spin_lock(&sctx->list_lock);
	sbio->next_free = sctx->first_free;
	sctx->first_free = sbio->index;
	spin_unlock(&sctx->list_lock);
2081 2082 2083 2084 2085 2086 2087 2088

	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);
	}

2089
	scrub_pending_bio_dec(sctx);
2090 2091 2092 2093
}

static void scrub_block_complete(struct scrub_block *sblock)
{
2094
	if (!sblock->no_io_error_seen) {
2095
		scrub_handle_errored_block(sblock);
2096 2097 2098 2099 2100 2101 2102 2103 2104
	} 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);
	}
2105 2106
}

2107
static int scrub_find_csum(struct scrub_ctx *sctx, u64 logical, u64 len,
A
Arne Jansen 已提交
2108 2109 2110 2111 2112 2113 2114
			   u8 *csum)
{
	struct btrfs_ordered_sum *sum = NULL;
	int ret = 0;
	unsigned long i;
	unsigned long num_sectors;

2115 2116
	while (!list_empty(&sctx->csum_list)) {
		sum = list_first_entry(&sctx->csum_list,
A
Arne Jansen 已提交
2117 2118 2119 2120 2121 2122
				       struct btrfs_ordered_sum, list);
		if (sum->bytenr > logical)
			return 0;
		if (sum->bytenr + sum->len > logical)
			break;

2123
		++sctx->stat.csum_discards;
A
Arne Jansen 已提交
2124 2125 2126 2127 2128 2129 2130
		list_del(&sum->list);
		kfree(sum);
		sum = NULL;
	}
	if (!sum)
		return 0;

2131
	num_sectors = sum->len / sctx->sectorsize;
A
Arne Jansen 已提交
2132 2133
	for (i = 0; i < num_sectors; ++i) {
		if (sum->sums[i].bytenr == logical) {
2134
			memcpy(csum, &sum->sums[i].sum, sctx->csum_size);
A
Arne Jansen 已提交
2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146
			ret = 1;
			break;
		}
	}
	if (ret && i == num_sectors - 1) {
		list_del(&sum->list);
		kfree(sum);
	}
	return ret;
}

/* scrub extent tries to collect up to 64 kB for each bio */
2147
static int scrub_extent(struct scrub_ctx *sctx, u64 logical, u64 len,
2148
			u64 physical, struct btrfs_device *dev, u64 flags,
2149
			u64 gen, int mirror_num, u64 physical_for_dev_replace)
A
Arne Jansen 已提交
2150 2151 2152
{
	int ret;
	u8 csum[BTRFS_CSUM_SIZE];
2153 2154 2155
	u32 blocksize;

	if (flags & BTRFS_EXTENT_FLAG_DATA) {
2156 2157 2158 2159 2160
		blocksize = sctx->sectorsize;
		spin_lock(&sctx->stat_lock);
		sctx->stat.data_extents_scrubbed++;
		sctx->stat.data_bytes_scrubbed += len;
		spin_unlock(&sctx->stat_lock);
2161
	} else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
2162
		WARN_ON(sctx->nodesize != sctx->leafsize);
2163 2164 2165 2166 2167
		blocksize = sctx->nodesize;
		spin_lock(&sctx->stat_lock);
		sctx->stat.tree_extents_scrubbed++;
		sctx->stat.tree_bytes_scrubbed += len;
		spin_unlock(&sctx->stat_lock);
2168
	} else {
2169
		blocksize = sctx->sectorsize;
2170
		WARN_ON(1);
2171
	}
A
Arne Jansen 已提交
2172 2173

	while (len) {
2174
		u64 l = min_t(u64, len, blocksize);
A
Arne Jansen 已提交
2175 2176 2177 2178
		int have_csum = 0;

		if (flags & BTRFS_EXTENT_FLAG_DATA) {
			/* push csums to sbio */
2179
			have_csum = scrub_find_csum(sctx, logical, l, csum);
A
Arne Jansen 已提交
2180
			if (have_csum == 0)
2181
				++sctx->stat.no_csum;
2182 2183 2184 2185 2186 2187
			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
2188
		}
2189
		ret = scrub_pages(sctx, logical, l, physical, dev, flags, gen,
2190 2191 2192
				  mirror_num, have_csum ? csum : NULL, 0,
				  physical_for_dev_replace);
behind_scrub_pages:
A
Arne Jansen 已提交
2193 2194 2195 2196 2197
		if (ret)
			return ret;
		len -= l;
		logical += l;
		physical += l;
2198
		physical_for_dev_replace += l;
A
Arne Jansen 已提交
2199 2200 2201 2202
	}
	return 0;
}

2203
static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
2204 2205
					   struct map_lookup *map,
					   struct btrfs_device *scrub_dev,
2206 2207
					   int num, u64 base, u64 length,
					   int is_dev_replace)
A
Arne Jansen 已提交
2208 2209
{
	struct btrfs_path *path;
2210
	struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;
A
Arne Jansen 已提交
2211 2212 2213
	struct btrfs_root *root = fs_info->extent_root;
	struct btrfs_root *csum_root = fs_info->csum_root;
	struct btrfs_extent_item *extent;
2214
	struct blk_plug plug;
A
Arne Jansen 已提交
2215 2216 2217 2218 2219 2220 2221 2222 2223 2224
	u64 flags;
	int ret;
	int slot;
	int i;
	u64 nstripes;
	struct extent_buffer *l;
	struct btrfs_key key;
	u64 physical;
	u64 logical;
	u64 generation;
2225
	int mirror_num;
A
Arne Jansen 已提交
2226 2227 2228 2229
	struct reada_control *reada1;
	struct reada_control *reada2;
	struct btrfs_key key_start;
	struct btrfs_key key_end;
A
Arne Jansen 已提交
2230 2231
	u64 increment = map->stripe_len;
	u64 offset;
2232 2233 2234 2235 2236
	u64 extent_logical;
	u64 extent_physical;
	u64 extent_len;
	struct btrfs_device *extent_dev;
	int extent_mirror_num;
A
Arne Jansen 已提交
2237 2238 2239 2240 2241 2242 2243

	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;
2244
		mirror_num = 1;
A
Arne Jansen 已提交
2245 2246 2247 2248
	} 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;
2249
		mirror_num = num % map->sub_stripes + 1;
A
Arne Jansen 已提交
2250 2251
	} else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
		increment = map->stripe_len;
2252
		mirror_num = num % map->num_stripes + 1;
A
Arne Jansen 已提交
2253 2254
	} else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
		increment = map->stripe_len;
2255
		mirror_num = num % map->num_stripes + 1;
A
Arne Jansen 已提交
2256 2257
	} else {
		increment = map->stripe_len;
2258
		mirror_num = 1;
A
Arne Jansen 已提交
2259 2260 2261 2262 2263 2264
	}

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

2265 2266 2267 2268 2269
	/*
	 * 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
2270 2271 2272 2273
	path->search_commit_root = 1;
	path->skip_locking = 1;

	/*
A
Arne Jansen 已提交
2274 2275 2276
	 * 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
2277 2278 2279
	 */
	logical = base + offset;

2280
	wait_event(sctx->list_wait,
2281
		   atomic_read(&sctx->bios_in_flight) == 0);
A
Arne Jansen 已提交
2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312
	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;
	key_end.type = BTRFS_EXTENT_ITEM_KEY;
	key_end.offset = (u64)0;
	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
2313
	}
A
Arne Jansen 已提交
2314 2315 2316
	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
2317 2318 2319 2320 2321

	/*
	 * collect all data csums for the stripe to avoid seeking during
	 * the scrub. This might currently (crc32) end up to be about 1MB
	 */
2322
	blk_start_plug(&plug);
A
Arne Jansen 已提交
2323 2324 2325 2326

	/*
	 * now find all extents for each stripe and scrub them
	 */
A
Arne Jansen 已提交
2327 2328
	logical = base + offset;
	physical = map->stripes[num].physical;
A
Arne Jansen 已提交
2329
	ret = 0;
A
Arne Jansen 已提交
2330
	for (i = 0; i < nstripes; ++i) {
A
Arne Jansen 已提交
2331 2332 2333 2334
		/*
		 * canceled?
		 */
		if (atomic_read(&fs_info->scrub_cancel_req) ||
2335
		    atomic_read(&sctx->cancel_req)) {
A
Arne Jansen 已提交
2336 2337 2338 2339 2340 2341 2342 2343
			ret = -ECANCELED;
			goto out;
		}
		/*
		 * check to see if we have to pause
		 */
		if (atomic_read(&fs_info->scrub_pause_req)) {
			/* push queued extents */
2344
			atomic_set(&sctx->wr_ctx.flush_all_writes, 1);
2345
			scrub_submit(sctx);
2346 2347 2348
			mutex_lock(&sctx->wr_ctx.wr_lock);
			scrub_wr_submit(sctx);
			mutex_unlock(&sctx->wr_ctx.wr_lock);
2349
			wait_event(sctx->list_wait,
2350
				   atomic_read(&sctx->bios_in_flight) == 0);
2351
			atomic_set(&sctx->wr_ctx.flush_all_writes, 0);
A
Arne Jansen 已提交
2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365
			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);
		}

A
Arne Jansen 已提交
2366 2367
		ret = btrfs_lookup_csums_range(csum_root, logical,
					       logical + map->stripe_len - 1,
2368
					       &sctx->csum_list, 1);
A
Arne Jansen 已提交
2369 2370 2371
		if (ret)
			goto out;

A
Arne Jansen 已提交
2372 2373 2374 2375 2376 2377 2378
		key.objectid = logical;
		key.type = BTRFS_EXTENT_ITEM_KEY;
		key.offset = (u64)0;

		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
		if (ret < 0)
			goto out;
2379
		if (ret > 0) {
A
Arne Jansen 已提交
2380 2381 2382 2383
			ret = btrfs_previous_item(root, path, 0,
						  BTRFS_EXTENT_ITEM_KEY);
			if (ret < 0)
				goto out;
2384 2385 2386 2387 2388 2389 2390 2391 2392
			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
2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443 2444 2445
		}

		while (1) {
			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;

				break;
			}
			btrfs_item_key_to_cpu(l, &key, slot);

			if (key.objectid + key.offset <= logical)
				goto next;

			if (key.objectid >= logical + map->stripe_len)
				break;

			if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY)
				goto next;

			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",
				       (unsigned long long)key.objectid,
				       (unsigned long long)logical);
				goto next;
			}

			/*
			 * trim extent to this stripe
			 */
			if (key.objectid < logical) {
				key.offset -= logical - key.objectid;
				key.objectid = logical;
			}
			if (key.objectid + key.offset >
			    logical + map->stripe_len) {
				key.offset = logical + map->stripe_len -
					     key.objectid;
			}

2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459
			extent_logical = key.objectid;
			extent_physical = key.objectid - logical + physical;
			extent_len = key.offset;
			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);
			ret = scrub_extent(sctx, extent_logical, extent_len,
					   extent_physical, extent_dev, flags,
					   generation, extent_mirror_num,
					   key.objectid - logical + physical);
A
Arne Jansen 已提交
2460 2461 2462 2463 2464 2465
			if (ret)
				goto out;

next:
			path->slots[0]++;
		}
C
Chris Mason 已提交
2466
		btrfs_release_path(path);
A
Arne Jansen 已提交
2467 2468
		logical += increment;
		physical += map->stripe_len;
2469 2470 2471
		spin_lock(&sctx->stat_lock);
		sctx->stat.last_physical = physical;
		spin_unlock(&sctx->stat_lock);
A
Arne Jansen 已提交
2472
	}
2473
out:
A
Arne Jansen 已提交
2474
	/* push queued extents */
2475
	scrub_submit(sctx);
2476 2477 2478
	mutex_lock(&sctx->wr_ctx.wr_lock);
	scrub_wr_submit(sctx);
	mutex_unlock(&sctx->wr_ctx.wr_lock);
A
Arne Jansen 已提交
2479

2480
	blk_finish_plug(&plug);
A
Arne Jansen 已提交
2481 2482 2483 2484
	btrfs_free_path(path);
	return ret < 0 ? ret : 0;
}

2485
static noinline_for_stack int scrub_chunk(struct scrub_ctx *sctx,
2486 2487 2488
					  struct btrfs_device *scrub_dev,
					  u64 chunk_tree, u64 chunk_objectid,
					  u64 chunk_offset, u64 length,
2489
					  u64 dev_offset, int is_dev_replace)
A
Arne Jansen 已提交
2490 2491
{
	struct btrfs_mapping_tree *map_tree =
2492
		&sctx->dev_root->fs_info->mapping_tree;
A
Arne Jansen 已提交
2493 2494 2495
	struct map_lookup *map;
	struct extent_map *em;
	int i;
2496
	int ret = 0;
A
Arne Jansen 已提交
2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512

	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) {
2513
		if (map->stripes[i].dev->bdev == scrub_dev->bdev &&
2514
		    map->stripes[i].physical == dev_offset) {
2515
			ret = scrub_stripe(sctx, map, scrub_dev, i,
2516 2517
					   chunk_offset, length,
					   is_dev_replace);
A
Arne Jansen 已提交
2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528
			if (ret)
				goto out;
		}
	}
out:
	free_extent_map(em);

	return ret;
}

static noinline_for_stack
2529
int scrub_enumerate_chunks(struct scrub_ctx *sctx,
2530 2531
			   struct btrfs_device *scrub_dev, u64 start, u64 end,
			   int is_dev_replace)
A
Arne Jansen 已提交
2532 2533 2534
{
	struct btrfs_dev_extent *dev_extent = NULL;
	struct btrfs_path *path;
2535
	struct btrfs_root *root = sctx->dev_root;
A
Arne Jansen 已提交
2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546
	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;
2547
	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
A
Arne Jansen 已提交
2548 2549 2550 2551 2552 2553 2554 2555 2556

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

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

2557
	key.objectid = scrub_dev->devid;
A
Arne Jansen 已提交
2558 2559 2560 2561 2562 2563
	key.offset = 0ull;
	key.type = BTRFS_DEV_EXTENT_KEY;

	while (1) {
		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
		if (ret < 0)
2564 2565 2566 2567 2568 2569 2570 2571 2572
			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
2573 2574 2575 2576 2577 2578

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

		btrfs_item_key_to_cpu(l, &found_key, slot);

2579
		if (found_key.objectid != scrub_dev->devid)
A
Arne Jansen 已提交
2580 2581
			break;

2582
		if (btrfs_key_type(&found_key) != BTRFS_DEV_EXTENT_KEY)
A
Arne Jansen 已提交
2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595
			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
2596
			btrfs_release_path(path);
A
Arne Jansen 已提交
2597 2598 2599 2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610
			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;
2611
			break;
A
Arne Jansen 已提交
2612
		}
2613 2614 2615
		dev_replace->cursor_right = found_key.offset + length;
		dev_replace->cursor_left = found_key.offset;
		dev_replace->item_needs_writeback = 1;
2616
		ret = scrub_chunk(sctx, scrub_dev, chunk_tree, chunk_objectid,
2617 2618 2619 2620 2621 2622 2623 2624 2625 2626 2627 2628 2629 2630 2631 2632 2633 2634 2635 2636 2637 2638 2639 2640 2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652 2653 2654 2655 2656
				  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
2657 2658 2659
		btrfs_put_block_group(cache);
		if (ret)
			break;
2660 2661
		if (is_dev_replace &&
		    atomic64_read(&dev_replace->num_write_errors) > 0) {
2662 2663 2664 2665 2666 2667 2668
			ret = -EIO;
			break;
		}
		if (sctx->stat.malloc_errors > 0) {
			ret = -ENOMEM;
			break;
		}
A
Arne Jansen 已提交
2669 2670

		key.offset = found_key.offset + length;
C
Chris Mason 已提交
2671
		btrfs_release_path(path);
A
Arne Jansen 已提交
2672 2673 2674
	}

	btrfs_free_path(path);
2675 2676 2677 2678 2679 2680

	/*
	 * 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
2681 2682
}

2683 2684
static noinline_for_stack int scrub_supers(struct scrub_ctx *sctx,
					   struct btrfs_device *scrub_dev)
A
Arne Jansen 已提交
2685 2686 2687 2688 2689
{
	int	i;
	u64	bytenr;
	u64	gen;
	int	ret;
2690
	struct btrfs_root *root = sctx->dev_root;
A
Arne Jansen 已提交
2691

2692 2693 2694
	if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)
		return -EIO;

A
Arne Jansen 已提交
2695 2696 2697 2698
	gen = root->fs_info->last_trans_committed;

	for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
		bytenr = btrfs_sb_offset(i);
2699
		if (bytenr + BTRFS_SUPER_INFO_SIZE > scrub_dev->total_bytes)
A
Arne Jansen 已提交
2700 2701
			break;

2702
		ret = scrub_pages(sctx, bytenr, BTRFS_SUPER_INFO_SIZE, bytenr,
2703
				  scrub_dev, BTRFS_EXTENT_FLAG_SUPER, gen, i,
2704
				  NULL, 1, bytenr);
A
Arne Jansen 已提交
2705 2706 2707
		if (ret)
			return ret;
	}
2708
	wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0);
A
Arne Jansen 已提交
2709 2710 2711 2712 2713 2714 2715

	return 0;
}

/*
 * get a reference count on fs_info->scrub_workers. start worker if necessary
 */
2716 2717
static noinline_for_stack int scrub_workers_get(struct btrfs_fs_info *fs_info,
						int is_dev_replace)
A
Arne Jansen 已提交
2718
{
2719
	int ret = 0;
A
Arne Jansen 已提交
2720 2721

	mutex_lock(&fs_info->scrub_lock);
A
Arne Jansen 已提交
2722
	if (fs_info->scrub_workers_refcnt == 0) {
2723 2724 2725 2726 2727 2728 2729
		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
2730
		fs_info->scrub_workers.idle_thresh = 4;
2731 2732 2733
		ret = btrfs_start_workers(&fs_info->scrub_workers);
		if (ret)
			goto out;
2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747
		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
2748
	}
A
Arne Jansen 已提交
2749
	++fs_info->scrub_workers_refcnt;
2750
out:
A
Arne Jansen 已提交
2751 2752
	mutex_unlock(&fs_info->scrub_lock);

2753
	return ret;
A
Arne Jansen 已提交
2754 2755
}

2756
static noinline_for_stack void scrub_workers_put(struct btrfs_fs_info *fs_info)
A
Arne Jansen 已提交
2757 2758
{
	mutex_lock(&fs_info->scrub_lock);
2759
	if (--fs_info->scrub_workers_refcnt == 0) {
A
Arne Jansen 已提交
2760
		btrfs_stop_workers(&fs_info->scrub_workers);
2761 2762 2763
		btrfs_stop_workers(&fs_info->scrub_wr_completion_workers);
		btrfs_stop_workers(&fs_info->scrub_nocow_workers);
	}
A
Arne Jansen 已提交
2764 2765 2766 2767
	WARN_ON(fs_info->scrub_workers_refcnt < 0);
	mutex_unlock(&fs_info->scrub_lock);
}

2768 2769
int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
		    u64 end, struct btrfs_scrub_progress *progress,
2770
		    int readonly, int is_dev_replace)
A
Arne Jansen 已提交
2771
{
2772
	struct scrub_ctx *sctx;
A
Arne Jansen 已提交
2773 2774 2775
	int ret;
	struct btrfs_device *dev;

2776
	if (btrfs_fs_closing(fs_info))
A
Arne Jansen 已提交
2777 2778 2779 2780 2781
		return -EINVAL;

	/*
	 * check some assumptions
	 */
2782
	if (fs_info->chunk_root->nodesize != fs_info->chunk_root->leafsize) {
2783 2784
		printk(KERN_ERR
		       "btrfs_scrub: size assumption nodesize == leafsize (%d == %d) fails\n",
2785 2786
		       fs_info->chunk_root->nodesize,
		       fs_info->chunk_root->leafsize);
2787 2788 2789
		return -EINVAL;
	}

2790
	if (fs_info->chunk_root->nodesize > BTRFS_STRIPE_LEN) {
2791 2792 2793 2794 2795 2796 2797
		/*
		 * 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",
2798
		       fs_info->chunk_root->nodesize, BTRFS_STRIPE_LEN);
2799 2800 2801
		return -EINVAL;
	}

2802
	if (fs_info->chunk_root->sectorsize != PAGE_SIZE) {
2803 2804 2805
		/* not supported for data w/o checksums */
		printk(KERN_ERR
		       "btrfs_scrub: size assumption sectorsize != PAGE_SIZE (%d != %lld) fails\n",
2806 2807
		       fs_info->chunk_root->sectorsize,
		       (unsigned long long)PAGE_SIZE);
A
Arne Jansen 已提交
2808 2809 2810
		return -EINVAL;
	}

2811 2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823 2824 2825 2826
	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;
	}

2827
	ret = scrub_workers_get(fs_info, is_dev_replace);
A
Arne Jansen 已提交
2828 2829 2830
	if (ret)
		return ret;

2831 2832
	mutex_lock(&fs_info->fs_devices->device_list_mutex);
	dev = btrfs_find_device(fs_info, devid, NULL, NULL);
2833
	if (!dev || (dev->missing && !is_dev_replace)) {
2834 2835
		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
		scrub_workers_put(fs_info);
A
Arne Jansen 已提交
2836 2837 2838 2839
		return -ENODEV;
	}
	mutex_lock(&fs_info->scrub_lock);

2840
	if (!dev->in_fs_metadata || dev->is_tgtdev_for_dev_replace) {
A
Arne Jansen 已提交
2841
		mutex_unlock(&fs_info->scrub_lock);
2842 2843 2844
		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
		scrub_workers_put(fs_info);
		return -EIO;
A
Arne Jansen 已提交
2845 2846
	}

2847 2848 2849 2850 2851
	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
2852
		mutex_unlock(&fs_info->scrub_lock);
2853 2854
		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
		scrub_workers_put(fs_info);
A
Arne Jansen 已提交
2855 2856
		return -EINPROGRESS;
	}
2857
	btrfs_dev_replace_unlock(&fs_info->dev_replace);
2858
	sctx = scrub_setup_ctx(dev, is_dev_replace);
2859
	if (IS_ERR(sctx)) {
A
Arne Jansen 已提交
2860
		mutex_unlock(&fs_info->scrub_lock);
2861 2862
		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
		scrub_workers_put(fs_info);
2863
		return PTR_ERR(sctx);
A
Arne Jansen 已提交
2864
	}
2865 2866
	sctx->readonly = readonly;
	dev->scrub_device = sctx;
A
Arne Jansen 已提交
2867 2868 2869

	atomic_inc(&fs_info->scrubs_running);
	mutex_unlock(&fs_info->scrub_lock);
2870
	mutex_unlock(&fs_info->fs_devices->device_list_mutex);
A
Arne Jansen 已提交
2871

2872 2873 2874 2875 2876
	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
2877 2878

	if (!ret)
2879 2880
		ret = scrub_enumerate_chunks(sctx, dev, start, end,
					     is_dev_replace);
A
Arne Jansen 已提交
2881

2882
	wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0);
A
Arne Jansen 已提交
2883 2884 2885
	atomic_dec(&fs_info->scrubs_running);
	wake_up(&fs_info->scrub_pause_wait);

2886
	wait_event(sctx->list_wait, atomic_read(&sctx->workers_pending) == 0);
2887

A
Arne Jansen 已提交
2888
	if (progress)
2889
		memcpy(progress, &sctx->stat, sizeof(*progress));
A
Arne Jansen 已提交
2890 2891 2892 2893 2894

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

2895
	scrub_free_ctx(sctx);
2896
	scrub_workers_put(fs_info);
A
Arne Jansen 已提交
2897 2898 2899 2900

	return ret;
}

2901
void btrfs_scrub_pause(struct btrfs_root *root)
A
Arne Jansen 已提交
2902 2903 2904 2905 2906 2907 2908 2909 2910 2911 2912 2913 2914 2915 2916 2917
{
	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);
}

2918
void btrfs_scrub_continue(struct btrfs_root *root)
A
Arne Jansen 已提交
2919 2920 2921 2922 2923 2924 2925
{
	struct btrfs_fs_info *fs_info = root->fs_info;

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

2926
void btrfs_scrub_pause_super(struct btrfs_root *root)
A
Arne Jansen 已提交
2927 2928 2929 2930
{
	down_write(&root->fs_info->scrub_super_lock);
}

2931
void btrfs_scrub_continue_super(struct btrfs_root *root)
A
Arne Jansen 已提交
2932 2933 2934 2935
{
	up_write(&root->fs_info->scrub_super_lock);
}

2936
int btrfs_scrub_cancel(struct btrfs_fs_info *fs_info)
A
Arne Jansen 已提交
2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951 2952 2953 2954 2955 2956
{
	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;
}

2957 2958
int btrfs_scrub_cancel_dev(struct btrfs_fs_info *fs_info,
			   struct btrfs_device *dev)
2959
{
2960
	struct scrub_ctx *sctx;
A
Arne Jansen 已提交
2961 2962

	mutex_lock(&fs_info->scrub_lock);
2963 2964
	sctx = dev->scrub_device;
	if (!sctx) {
A
Arne Jansen 已提交
2965 2966 2967
		mutex_unlock(&fs_info->scrub_lock);
		return -ENOTCONN;
	}
2968
	atomic_inc(&sctx->cancel_req);
A
Arne Jansen 已提交
2969 2970 2971 2972 2973 2974 2975 2976 2977 2978
	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
2979

A
Arne Jansen 已提交
2980 2981 2982 2983 2984 2985 2986 2987 2988 2989 2990
int btrfs_scrub_cancel_devid(struct btrfs_root *root, u64 devid)
{
	struct btrfs_fs_info *fs_info = root->fs_info;
	struct btrfs_device *dev;
	int ret;

	/*
	 * we have to hold the device_list_mutex here so the device
	 * does not go away in cancel_dev. FIXME: find a better solution
	 */
	mutex_lock(&fs_info->fs_devices->device_list_mutex);
2991
	dev = btrfs_find_device(fs_info, devid, NULL, NULL);
A
Arne Jansen 已提交
2992 2993 2994 2995
	if (!dev) {
		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
		return -ENODEV;
	}
2996
	ret = btrfs_scrub_cancel_dev(fs_info, dev);
A
Arne Jansen 已提交
2997 2998 2999 3000 3001 3002 3003 3004 3005
	mutex_unlock(&fs_info->fs_devices->device_list_mutex);

	return ret;
}

int btrfs_scrub_progress(struct btrfs_root *root, u64 devid,
			 struct btrfs_scrub_progress *progress)
{
	struct btrfs_device *dev;
3006
	struct scrub_ctx *sctx = NULL;
A
Arne Jansen 已提交
3007 3008

	mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
3009
	dev = btrfs_find_device(root->fs_info, devid, NULL, NULL);
A
Arne Jansen 已提交
3010
	if (dev)
3011 3012 3013
		sctx = dev->scrub_device;
	if (sctx)
		memcpy(progress, &sctx->stat, sizeof(*progress));
A
Arne Jansen 已提交
3014 3015
	mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);

3016
	return dev ? (sctx ? 0 : -ENOTCONN) : -ENODEV;
A
Arne Jansen 已提交
3017
}
3018 3019 3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031 3032 3033 3034 3035 3036 3037 3038 3039 3040 3041 3042 3043 3044 3045 3046 3047 3048 3049 3050 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 3174 3175 3176 3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188 3189 3190 3191 3192 3193 3194 3195 3196 3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 3213 3214 3215 3216 3217 3218 3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238 3239 3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263 3264 3265 3266 3267 3268 3269 3270 3271 3272 3273 3274 3275 3276 3277 3278 3279 3280 3281 3282 3283 3284 3285 3286

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",
			(unsigned long long)logical,
			(unsigned long long)physical_for_dev_replace,
			(unsigned long long)len,
			(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)
{
	unsigned long index;
	struct scrub_copy_nocow_ctx *nocow_ctx = ctx;
	int ret = 0;
	struct btrfs_key key;
	struct inode *inode = NULL;
	struct btrfs_root *local_root;
	u64 physical_for_dev_replace;
	u64 len;
	struct btrfs_fs_info *fs_info = nocow_ctx->sctx->dev_root->fs_info;

	key.objectid = root;
	key.type = BTRFS_ROOT_ITEM_KEY;
	key.offset = (u64)-1;
	local_root = btrfs_read_fs_root_no_name(fs_info, &key);
	if (IS_ERR(local_root))
		return PTR_ERR(local_root);

	key.type = BTRFS_INODE_ITEM_KEY;
	key.objectid = inum;
	key.offset = 0;
	inode = btrfs_iget(fs_info->sb, &key, local_root, NULL);
	if (IS_ERR(inode))
		return PTR_ERR(inode);

	physical_for_dev_replace = nocow_ctx->physical_for_dev_replace;
	len = nocow_ctx->len;
	while (len >= PAGE_CACHE_SIZE) {
		struct page *page = NULL;
		int ret_sub;

		index = offset >> PAGE_CACHE_SHIFT;

		page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
		if (!page) {
			pr_err("find_or_create_page() failed\n");
			ret = -ENOMEM;
			goto next_page;
		}

		if (PageUptodate(page)) {
			if (PageDirty(page))
				goto next_page;
		} else {
			ClearPageError(page);
			ret_sub = extent_read_full_page(&BTRFS_I(inode)->
							 io_tree,
							page, btrfs_get_extent,
							nocow_ctx->mirror_num);
			if (ret_sub) {
				ret = ret_sub;
				goto next_page;
			}
			wait_on_page_locked(page);
			if (!PageUptodate(page)) {
				ret = -EIO;
				goto next_page;
			}
		}
		ret_sub = write_page_nocow(nocow_ctx->sctx,
					   physical_for_dev_replace, page);
		if (ret_sub) {
			ret = ret_sub;
			goto next_page;
		}

next_page:
		if (page) {
			unlock_page(page);
			put_page(page);
		}
		offset += PAGE_CACHE_SIZE;
		physical_for_dev_replace += PAGE_CACHE_SIZE;
		len -= PAGE_CACHE_SIZE;
	}

	if (inode)
		iput(inode);
	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;
	}
	bio = bio_alloc(GFP_NOFS, 1);
	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;
}