scrub.c 89.3 KB
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/*
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 * Copyright (C) 2011, 2012 STRATO.  All rights reserved.
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 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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	if (!sctx)
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		return;

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	scrub_free_wr_ctx(&sctx->wr_ctx);

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

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

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	scrub_free_csums(sctx);
	kfree(sctx);
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}

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

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

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

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

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

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

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

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

	if (ret < 0)
		goto err;

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

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

	free_ipath(ipath);
	return 0;
}

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

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	path = btrfs_alloc_path();

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

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

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

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

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

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

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

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

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

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

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

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

	index = offset >> PAGE_CACHE_SHIFT;

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

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

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

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

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

	if (ret < 0)
		return ret;

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

	return -EIO;
}

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

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

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

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

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

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

out:
	if (trans && !IS_ERR(trans))
		btrfs_end_transaction(trans, fixup->root);
	if (uncorrectable) {
749 750 751
		spin_lock(&sctx->stat_lock);
		++sctx->stat.uncorrectable_errors;
		spin_unlock(&sctx->stat_lock);
752 753 754
		btrfs_dev_replace_stats_inc(
			&sctx->dev_root->fs_info->dev_replace.
			num_uncorrectable_read_errors);
755
		printk_ratelimited_in_rcu(KERN_ERR
756
			"btrfs: unable to fixup (nodatasum) error at logical %llu on dev %s\n",
757
			(unsigned long long)fixup->logical,
758
			rcu_str_deref(fixup->dev->name));
759 760 761 762 763
	}

	btrfs_free_path(path);
	kfree(fixup);

764
	scrub_pending_trans_workers_dec(sctx);
765 766
}

A
Arne Jansen 已提交
767
/*
768 769 770 771 772 773
 * 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
774
 */
775
static int scrub_handle_errored_block(struct scrub_block *sblock_to_check)
A
Arne Jansen 已提交
776
{
777
	struct scrub_ctx *sctx = sblock_to_check->sctx;
778
	struct btrfs_device *dev;
779 780 781 782 783 784 785 786 787 788 789 790 791 792
	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;
793
	static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
794 795 796
				      DEFAULT_RATELIMIT_BURST);

	BUG_ON(sblock_to_check->page_count < 1);
797
	fs_info = sctx->dev_root->fs_info;
798 799 800 801 802 803 804 805 806 807 808
	if (sblock_to_check->pagev[0]->flags & BTRFS_EXTENT_FLAG_SUPER) {
		/*
		 * if we find an error in a super block, we just report it.
		 * They will get written with the next transaction commit
		 * anyway
		 */
		spin_lock(&sctx->stat_lock);
		++sctx->stat.super_errors;
		spin_unlock(&sctx->stat_lock);
		return 0;
	}
809
	length = sblock_to_check->page_count * PAGE_SIZE;
810 811 812 813 814
	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 &
815
			BTRFS_EXTENT_FLAG_DATA);
816 817 818
	have_csum = sblock_to_check->pagev[0]->have_csum;
	csum = sblock_to_check->pagev[0]->csum;
	dev = sblock_to_check->pagev[0]->dev;
819

820 821 822 823 824
	if (sctx->is_dev_replace && !is_metadata && !have_csum) {
		sblocks_for_recheck = NULL;
		goto nodatasum_case;
	}

825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857
	/*
	 * 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) {
858 859 860 861 862
		spin_lock(&sctx->stat_lock);
		sctx->stat.malloc_errors++;
		sctx->stat.read_errors++;
		sctx->stat.uncorrectable_errors++;
		spin_unlock(&sctx->stat_lock);
863
		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
864
		goto out;
A
Arne Jansen 已提交
865 866
	}

867
	/* setup the context, map the logical blocks and alloc the pages */
868
	ret = scrub_setup_recheck_block(sctx, fs_info, sblock_to_check, length,
869 870
					logical, sblocks_for_recheck);
	if (ret) {
871 872 873 874
		spin_lock(&sctx->stat_lock);
		sctx->stat.read_errors++;
		sctx->stat.uncorrectable_errors++;
		spin_unlock(&sctx->stat_lock);
875
		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
876 877 878 879
		goto out;
	}
	BUG_ON(failed_mirror_index >= BTRFS_MAX_MIRRORS);
	sblock_bad = sblocks_for_recheck + failed_mirror_index;
880

881
	/* build and submit the bios for the failed mirror, check checksums */
882 883
	scrub_recheck_block(fs_info, sblock_bad, is_metadata, have_csum,
			    csum, generation, sctx->csum_size);
A
Arne Jansen 已提交
884

885 886 887 888 889 890 891 892 893 894
	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)
		 */
895 896 897
		spin_lock(&sctx->stat_lock);
		sctx->stat.unverified_errors++;
		spin_unlock(&sctx->stat_lock);
A
Arne Jansen 已提交
898

899 900
		if (sctx->is_dev_replace)
			scrub_write_block_to_dev_replace(sblock_bad);
901
		goto out;
A
Arne Jansen 已提交
902 903
	}

904
	if (!sblock_bad->no_io_error_seen) {
905 906 907
		spin_lock(&sctx->stat_lock);
		sctx->stat.read_errors++;
		spin_unlock(&sctx->stat_lock);
908 909
		if (__ratelimit(&_rs))
			scrub_print_warning("i/o error", sblock_to_check);
910
		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
911
	} else if (sblock_bad->checksum_error) {
912 913 914
		spin_lock(&sctx->stat_lock);
		sctx->stat.csum_errors++;
		spin_unlock(&sctx->stat_lock);
915 916
		if (__ratelimit(&_rs))
			scrub_print_warning("checksum error", sblock_to_check);
917
		btrfs_dev_stat_inc_and_print(dev,
918
					     BTRFS_DEV_STAT_CORRUPTION_ERRS);
919
	} else if (sblock_bad->header_error) {
920 921 922
		spin_lock(&sctx->stat_lock);
		sctx->stat.verify_errors++;
		spin_unlock(&sctx->stat_lock);
923 924 925
		if (__ratelimit(&_rs))
			scrub_print_warning("checksum/header error",
					    sblock_to_check);
926
		if (sblock_bad->generation_error)
927
			btrfs_dev_stat_inc_and_print(dev,
928 929
				BTRFS_DEV_STAT_GENERATION_ERRS);
		else
930
			btrfs_dev_stat_inc_and_print(dev,
931
				BTRFS_DEV_STAT_CORRUPTION_ERRS);
932
	}
A
Arne Jansen 已提交
933

934
	if (sctx->readonly && !sctx->is_dev_replace)
935
		goto did_not_correct_error;
A
Arne Jansen 已提交
936

937 938
	if (!is_metadata && !have_csum) {
		struct scrub_fixup_nodatasum *fixup_nodatasum;
A
Arne Jansen 已提交
939

940 941 942
nodatasum_case:
		WARN_ON(sctx->is_dev_replace);

943 944 945 946 947 948 949 950 951 952
		/*
		 * !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;
953
		fixup_nodatasum->sctx = sctx;
954
		fixup_nodatasum->dev = dev;
955 956 957
		fixup_nodatasum->logical = logical;
		fixup_nodatasum->root = fs_info->extent_root;
		fixup_nodatasum->mirror_num = failed_mirror_index + 1;
958
		scrub_pending_trans_workers_inc(sctx);
959 960 961 962
		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
963 964
	}

965 966
	/*
	 * now build and submit the bios for the other mirrors, check
967 968
	 * checksums.
	 * First try to pick the mirror which is completely without I/O
969 970 971 972 973 974 975 976 977 978 979 980 981 982 983
	 * 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++) {
984
		struct scrub_block *sblock_other;
985

986 987 988 989 990
		if (mirror_index == failed_mirror_index)
			continue;
		sblock_other = sblocks_for_recheck + mirror_index;

		/* build and submit the bios, check checksums */
991 992 993 994 995
		scrub_recheck_block(fs_info, sblock_other, is_metadata,
				    have_csum, csum, generation,
				    sctx->csum_size);

		if (!sblock_other->header_error &&
996 997
		    !sblock_other->checksum_error &&
		    sblock_other->no_io_error_seen) {
998 999 1000 1001 1002 1003 1004 1005 1006
			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);
			}
1007 1008 1009 1010
			if (0 == ret)
				goto corrected_error;
		}
	}
A
Arne Jansen 已提交
1011 1012

	/*
1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070
	 * 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
1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091
	 * 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
1092 1093
	 */

1094 1095 1096 1097 1098 1099
	/* 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++) {
1100
		struct scrub_page *page_bad = sblock_bad->pagev[page_num];
1101 1102

		if (!page_bad->io_error)
A
Arne Jansen 已提交
1103
			continue;
1104 1105 1106 1107 1108 1109 1110

		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;
1111 1112
			struct scrub_page *page_other = sblock_other->pagev[
							page_num];
1113 1114 1115 1116 1117 1118 1119 1120 1121

			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
1122
		}
A
Arne Jansen 已提交
1123

1124 1125 1126 1127
		if (page_bad->io_error) {
			/* did not find a mirror to copy the page from */
			success = 0;
		}
A
Arne Jansen 已提交
1128 1129
	}

1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140
	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.
			 */
1141 1142 1143 1144
			scrub_recheck_block(fs_info, sblock_bad,
					    is_metadata, have_csum, csum,
					    generation, sctx->csum_size);
			if (!sblock_bad->header_error &&
1145 1146 1147 1148 1149 1150 1151
			    !sblock_bad->checksum_error &&
			    sblock_bad->no_io_error_seen)
				goto corrected_error;
			else
				goto did_not_correct_error;
		} else {
corrected_error:
1152 1153 1154
			spin_lock(&sctx->stat_lock);
			sctx->stat.corrected_errors++;
			spin_unlock(&sctx->stat_lock);
1155
			printk_ratelimited_in_rcu(KERN_ERR
1156
				"btrfs: fixed up error at logical %llu on dev %s\n",
1157
				(unsigned long long)logical,
1158
				rcu_str_deref(dev->name));
A
Arne Jansen 已提交
1159
		}
1160 1161
	} else {
did_not_correct_error:
1162 1163 1164
		spin_lock(&sctx->stat_lock);
		sctx->stat.uncorrectable_errors++;
		spin_unlock(&sctx->stat_lock);
1165
		printk_ratelimited_in_rcu(KERN_ERR
1166
			"btrfs: unable to fixup (regular) error at logical %llu on dev %s\n",
1167
			(unsigned long long)logical,
1168
			rcu_str_deref(dev->name));
I
Ilya Dryomov 已提交
1169
	}
A
Arne Jansen 已提交
1170

1171 1172 1173 1174 1175 1176 1177 1178
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;

1179 1180 1181 1182 1183
			for (page_index = 0; page_index < sblock->page_count;
			     page_index++) {
				sblock->pagev[page_index]->sblock = NULL;
				scrub_page_put(sblock->pagev[page_index]);
			}
1184 1185 1186
		}
		kfree(sblocks_for_recheck);
	}
A
Arne Jansen 已提交
1187

1188 1189
	return 0;
}
A
Arne Jansen 已提交
1190

1191
static int scrub_setup_recheck_block(struct scrub_ctx *sctx,
1192
				     struct btrfs_fs_info *fs_info,
1193
				     struct scrub_block *original_sblock,
1194 1195 1196 1197 1198 1199 1200 1201
				     u64 length, u64 logical,
				     struct scrub_block *sblocks_for_recheck)
{
	int page_index;
	int mirror_index;
	int ret;

	/*
1202
	 * note: the two members ref_count and outstanding_pages
1203 1204 1205 1206 1207 1208 1209 1210 1211
	 * 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
1212

1213 1214 1215 1216
		/*
		 * with a length of PAGE_SIZE, each returned stripe
		 * represents one mirror
		 */
1217 1218
		ret = btrfs_map_block(fs_info, REQ_GET_READ_MIRRORS, logical,
				      &mapped_length, &bbio, 0);
1219 1220 1221 1222
		if (ret || !bbio || mapped_length < sublen) {
			kfree(bbio);
			return -EIO;
		}
A
Arne Jansen 已提交
1223

1224
		BUG_ON(page_index >= SCRUB_PAGES_PER_RD_BIO);
1225 1226 1227 1228 1229 1230 1231 1232 1233
		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;
1234 1235 1236 1237
			sblock->sctx = sctx;
			page = kzalloc(sizeof(*page), GFP_NOFS);
			if (!page) {
leave_nomem:
1238 1239 1240
				spin_lock(&sctx->stat_lock);
				sctx->stat.malloc_errors++;
				spin_unlock(&sctx->stat_lock);
1241
				kfree(bbio);
1242 1243
				return -ENOMEM;
			}
1244 1245 1246 1247
			scrub_page_get(page);
			sblock->pagev[page_index] = page;
			page->logical = logical;
			page->physical = bbio->stripes[mirror_index].physical;
1248 1249 1250 1251
			BUG_ON(page_index >= original_sblock->page_count);
			page->physical_for_dev_replace =
				original_sblock->pagev[page_index]->
				physical_for_dev_replace;
1252 1253 1254
			/* for missing devices, dev->bdev is NULL */
			page->dev = bbio->stripes[mirror_index].dev;
			page->mirror_num = mirror_index + 1;
1255
			sblock->page_count++;
1256 1257 1258
			page->page = alloc_page(GFP_NOFS);
			if (!page->page)
				goto leave_nomem;
1259 1260 1261 1262 1263 1264 1265 1266
		}
		kfree(bbio);
		length -= sublen;
		logical += sublen;
		page_index++;
	}

	return 0;
I
Ilya Dryomov 已提交
1267 1268
}

1269 1270 1271 1272 1273 1274 1275
/*
 * 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.
 */
1276 1277 1278 1279
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
1280
{
1281
	int page_num;
I
Ilya Dryomov 已提交
1282

1283 1284 1285
	sblock->no_io_error_seen = 1;
	sblock->header_error = 0;
	sblock->checksum_error = 0;
I
Ilya Dryomov 已提交
1286

1287 1288
	for (page_num = 0; page_num < sblock->page_count; page_num++) {
		struct bio *bio;
1289
		struct scrub_page *page = sblock->pagev[page_num];
1290 1291
		DECLARE_COMPLETION_ONSTACK(complete);

1292
		if (page->dev->bdev == NULL) {
1293 1294 1295 1296 1297
			page->io_error = 1;
			sblock->no_io_error_seen = 0;
			continue;
		}

1298
		WARN_ON(!page->page);
1299
		bio = bio_alloc(GFP_NOFS, 1);
1300 1301 1302 1303 1304
		if (!bio) {
			page->io_error = 1;
			sblock->no_io_error_seen = 0;
			continue;
		}
1305
		bio->bi_bdev = page->dev->bdev;
1306 1307 1308 1309
		bio->bi_sector = page->physical >> 9;
		bio->bi_end_io = scrub_complete_bio_end_io;
		bio->bi_private = &complete;

1310
		bio_add_page(bio, page->page, PAGE_SIZE, 0);
1311
		btrfsic_submit_bio(READ, bio);
I
Ilya Dryomov 已提交
1312

1313 1314
		/* this will also unplug the queue */
		wait_for_completion(&complete);
I
Ilya Dryomov 已提交
1315

1316 1317 1318 1319 1320
		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
1321

1322 1323 1324 1325 1326
	if (sblock->no_io_error_seen)
		scrub_recheck_block_checksum(fs_info, sblock, is_metadata,
					     have_csum, csum, generation,
					     csum_size);

1327
	return;
A
Arne Jansen 已提交
1328 1329
}

1330 1331 1332 1333 1334
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
1335
{
1336 1337 1338 1339 1340
	int page_num;
	u8 calculated_csum[BTRFS_CSUM_SIZE];
	u32 crc = ~(u32)0;
	void *mapped_buffer;

1341
	WARN_ON(!sblock->pagev[0]->page);
1342 1343 1344
	if (is_metadata) {
		struct btrfs_header *h;

1345
		mapped_buffer = kmap_atomic(sblock->pagev[0]->page);
1346 1347
		h = (struct btrfs_header *)mapped_buffer;

1348
		if (sblock->pagev[0]->logical != le64_to_cpu(h->bytenr) ||
1349 1350
		    memcmp(h->fsid, fs_info->fsid, BTRFS_UUID_SIZE) ||
		    memcmp(h->chunk_tree_uuid, fs_info->chunk_tree_uuid,
1351
			   BTRFS_UUID_SIZE)) {
1352
			sblock->header_error = 1;
1353 1354 1355 1356
		} else if (generation != le64_to_cpu(h->generation)) {
			sblock->header_error = 1;
			sblock->generation_error = 1;
		}
1357 1358 1359 1360
		csum = h->csum;
	} else {
		if (!have_csum)
			return;
A
Arne Jansen 已提交
1361

1362
		mapped_buffer = kmap_atomic(sblock->pagev[0]->page);
1363
	}
A
Arne Jansen 已提交
1364

1365 1366
	for (page_num = 0;;) {
		if (page_num == 0 && is_metadata)
1367
			crc = btrfs_csum_data(
1368 1369 1370
				((u8 *)mapped_buffer) + BTRFS_CSUM_SIZE,
				crc, PAGE_SIZE - BTRFS_CSUM_SIZE);
		else
1371
			crc = btrfs_csum_data(mapped_buffer, crc, PAGE_SIZE);
1372

1373
		kunmap_atomic(mapped_buffer);
1374 1375 1376
		page_num++;
		if (page_num >= sblock->page_count)
			break;
1377
		WARN_ON(!sblock->pagev[page_num]->page);
1378

1379
		mapped_buffer = kmap_atomic(sblock->pagev[page_num]->page);
1380 1381 1382 1383 1384
	}

	btrfs_csum_final(crc, calculated_csum);
	if (memcmp(calculated_csum, csum, csum_size))
		sblock->checksum_error = 1;
A
Arne Jansen 已提交
1385 1386
}

1387
static void scrub_complete_bio_end_io(struct bio *bio, int err)
A
Arne Jansen 已提交
1388
{
1389 1390
	complete((struct completion *)bio->bi_private);
}
A
Arne Jansen 已提交
1391

1392 1393 1394 1395 1396 1397
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
1398

1399 1400
	for (page_num = 0; page_num < sblock_bad->page_count; page_num++) {
		int ret_sub;
I
Ilya Dryomov 已提交
1401

1402 1403 1404 1405 1406 1407
		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
1408
	}
1409 1410 1411 1412 1413 1414 1415 1416

	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)
{
1417 1418
	struct scrub_page *page_bad = sblock_bad->pagev[page_num];
	struct scrub_page *page_good = sblock_good->pagev[page_num];
1419

1420 1421
	BUG_ON(page_bad->page == NULL);
	BUG_ON(page_good->page == NULL);
1422 1423 1424 1425 1426 1427
	if (force_write || sblock_bad->header_error ||
	    sblock_bad->checksum_error || page_bad->io_error) {
		struct bio *bio;
		int ret;
		DECLARE_COMPLETION_ONSTACK(complete);

1428 1429 1430 1431 1432 1433
		if (!page_bad->dev->bdev) {
			printk_ratelimited(KERN_WARNING
				"btrfs: scrub_repair_page_from_good_copy(bdev == NULL) is unexpected!\n");
			return -EIO;
		}

1434
		bio = bio_alloc(GFP_NOFS, 1);
1435 1436
		if (!bio)
			return -EIO;
1437
		bio->bi_bdev = page_bad->dev->bdev;
1438 1439 1440 1441 1442 1443 1444 1445
		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;
1446
		}
1447 1448 1449 1450
		btrfsic_submit_bio(WRITE, bio);

		/* this will also unplug the queue */
		wait_for_completion(&complete);
1451 1452 1453
		if (!bio_flagged(bio, BIO_UPTODATE)) {
			btrfs_dev_stat_inc_and_print(page_bad->dev,
				BTRFS_DEV_STAT_WRITE_ERRS);
1454 1455 1456
			btrfs_dev_replace_stats_inc(
				&sblock_bad->sctx->dev_root->fs_info->
				dev_replace.num_write_errors);
1457 1458 1459
			bio_put(bio);
			return -EIO;
		}
1460
		bio_put(bio);
A
Arne Jansen 已提交
1461 1462
	}

1463 1464 1465
	return 0;
}

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 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627
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)
1628 1629 1630 1631
{
	u64 flags;
	int ret;

1632 1633
	WARN_ON(sblock->page_count < 1);
	flags = sblock->pagev[0]->flags;
1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644
	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);
1645 1646

	return ret;
A
Arne Jansen 已提交
1647 1648
}

1649
static int scrub_checksum_data(struct scrub_block *sblock)
A
Arne Jansen 已提交
1650
{
1651
	struct scrub_ctx *sctx = sblock->sctx;
A
Arne Jansen 已提交
1652
	u8 csum[BTRFS_CSUM_SIZE];
1653 1654 1655
	u8 *on_disk_csum;
	struct page *page;
	void *buffer;
A
Arne Jansen 已提交
1656 1657
	u32 crc = ~(u32)0;
	int fail = 0;
1658 1659
	u64 len;
	int index;
A
Arne Jansen 已提交
1660

1661
	BUG_ON(sblock->page_count < 1);
1662
	if (!sblock->pagev[0]->have_csum)
A
Arne Jansen 已提交
1663 1664
		return 0;

1665 1666
	on_disk_csum = sblock->pagev[0]->csum;
	page = sblock->pagev[0]->page;
1667
	buffer = kmap_atomic(page);
1668

1669
	len = sctx->sectorsize;
1670 1671 1672 1673
	index = 0;
	for (;;) {
		u64 l = min_t(u64, len, PAGE_SIZE);

1674
		crc = btrfs_csum_data(buffer, crc, l);
1675
		kunmap_atomic(buffer);
1676 1677 1678 1679 1680
		len -= l;
		if (len == 0)
			break;
		index++;
		BUG_ON(index >= sblock->page_count);
1681 1682
		BUG_ON(!sblock->pagev[index]->page);
		page = sblock->pagev[index]->page;
1683
		buffer = kmap_atomic(page);
1684 1685
	}

A
Arne Jansen 已提交
1686
	btrfs_csum_final(crc, csum);
1687
	if (memcmp(csum, on_disk_csum, sctx->csum_size))
A
Arne Jansen 已提交
1688 1689 1690 1691 1692
		fail = 1;

	return fail;
}

1693
static int scrub_checksum_tree_block(struct scrub_block *sblock)
A
Arne Jansen 已提交
1694
{
1695
	struct scrub_ctx *sctx = sblock->sctx;
A
Arne Jansen 已提交
1696
	struct btrfs_header *h;
1697
	struct btrfs_root *root = sctx->dev_root;
A
Arne Jansen 已提交
1698
	struct btrfs_fs_info *fs_info = root->fs_info;
1699 1700 1701 1702 1703 1704
	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
1705 1706 1707
	u32 crc = ~(u32)0;
	int fail = 0;
	int crc_fail = 0;
1708 1709 1710 1711
	u64 len;
	int index;

	BUG_ON(sblock->page_count < 1);
1712
	page = sblock->pagev[0]->page;
1713
	mapped_buffer = kmap_atomic(page);
1714
	h = (struct btrfs_header *)mapped_buffer;
1715
	memcpy(on_disk_csum, h->csum, sctx->csum_size);
A
Arne Jansen 已提交
1716 1717 1718 1719 1720 1721 1722

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

1723
	if (sblock->pagev[0]->logical != le64_to_cpu(h->bytenr))
A
Arne Jansen 已提交
1724 1725
		++fail;

1726
	if (sblock->pagev[0]->generation != le64_to_cpu(h->generation))
A
Arne Jansen 已提交
1727 1728 1729 1730 1731 1732 1733 1734 1735
		++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;

1736
	WARN_ON(sctx->nodesize != sctx->leafsize);
1737
	len = sctx->nodesize - BTRFS_CSUM_SIZE;
1738 1739 1740 1741 1742 1743
	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);

1744
		crc = btrfs_csum_data(p, crc, l);
1745
		kunmap_atomic(mapped_buffer);
1746 1747 1748 1749 1750
		len -= l;
		if (len == 0)
			break;
		index++;
		BUG_ON(index >= sblock->page_count);
1751 1752
		BUG_ON(!sblock->pagev[index]->page);
		page = sblock->pagev[index]->page;
1753
		mapped_buffer = kmap_atomic(page);
1754 1755 1756 1757 1758
		mapped_size = PAGE_SIZE;
		p = mapped_buffer;
	}

	btrfs_csum_final(crc, calculated_csum);
1759
	if (memcmp(calculated_csum, on_disk_csum, sctx->csum_size))
A
Arne Jansen 已提交
1760 1761 1762 1763 1764
		++crc_fail;

	return fail || crc_fail;
}

1765
static int scrub_checksum_super(struct scrub_block *sblock)
A
Arne Jansen 已提交
1766 1767
{
	struct btrfs_super_block *s;
1768
	struct scrub_ctx *sctx = sblock->sctx;
1769
	struct btrfs_root *root = sctx->dev_root;
A
Arne Jansen 已提交
1770
	struct btrfs_fs_info *fs_info = root->fs_info;
1771 1772 1773 1774 1775 1776
	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
1777
	u32 crc = ~(u32)0;
1778 1779
	int fail_gen = 0;
	int fail_cor = 0;
1780 1781
	u64 len;
	int index;
A
Arne Jansen 已提交
1782

1783
	BUG_ON(sblock->page_count < 1);
1784
	page = sblock->pagev[0]->page;
1785
	mapped_buffer = kmap_atomic(page);
1786
	s = (struct btrfs_super_block *)mapped_buffer;
1787
	memcpy(on_disk_csum, s->csum, sctx->csum_size);
A
Arne Jansen 已提交
1788

1789
	if (sblock->pagev[0]->logical != le64_to_cpu(s->bytenr))
1790
		++fail_cor;
A
Arne Jansen 已提交
1791

1792
	if (sblock->pagev[0]->generation != le64_to_cpu(s->generation))
1793
		++fail_gen;
A
Arne Jansen 已提交
1794 1795

	if (memcmp(s->fsid, fs_info->fsid, BTRFS_UUID_SIZE))
1796
		++fail_cor;
A
Arne Jansen 已提交
1797

1798 1799 1800 1801 1802 1803 1804
	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);

1805
		crc = btrfs_csum_data(p, crc, l);
1806
		kunmap_atomic(mapped_buffer);
1807 1808 1809 1810 1811
		len -= l;
		if (len == 0)
			break;
		index++;
		BUG_ON(index >= sblock->page_count);
1812 1813
		BUG_ON(!sblock->pagev[index]->page);
		page = sblock->pagev[index]->page;
1814
		mapped_buffer = kmap_atomic(page);
1815 1816 1817 1818 1819
		mapped_size = PAGE_SIZE;
		p = mapped_buffer;
	}

	btrfs_csum_final(crc, calculated_csum);
1820
	if (memcmp(calculated_csum, on_disk_csum, sctx->csum_size))
1821
		++fail_cor;
A
Arne Jansen 已提交
1822

1823
	if (fail_cor + fail_gen) {
A
Arne Jansen 已提交
1824 1825 1826 1827 1828
		/*
		 * if we find an error in a super block, we just report it.
		 * They will get written with the next transaction commit
		 * anyway
		 */
1829 1830 1831
		spin_lock(&sctx->stat_lock);
		++sctx->stat.super_errors;
		spin_unlock(&sctx->stat_lock);
1832
		if (fail_cor)
1833
			btrfs_dev_stat_inc_and_print(sblock->pagev[0]->dev,
1834 1835
				BTRFS_DEV_STAT_CORRUPTION_ERRS);
		else
1836
			btrfs_dev_stat_inc_and_print(sblock->pagev[0]->dev,
1837
				BTRFS_DEV_STAT_GENERATION_ERRS);
A
Arne Jansen 已提交
1838 1839
	}

1840
	return fail_cor + fail_gen;
A
Arne Jansen 已提交
1841 1842
}

1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853
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++)
1854
			scrub_page_put(sblock->pagev[i]);
1855 1856 1857 1858
		kfree(sblock);
	}
}

1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872
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);
	}
}

1873
static void scrub_submit(struct scrub_ctx *sctx)
A
Arne Jansen 已提交
1874 1875 1876
{
	struct scrub_bio *sbio;

1877
	if (sctx->curr == -1)
S
Stefan Behrens 已提交
1878
		return;
A
Arne Jansen 已提交
1879

1880 1881
	sbio = sctx->bios[sctx->curr];
	sctx->curr = -1;
1882
	scrub_pending_bio_inc(sctx);
A
Arne Jansen 已提交
1883

1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897
	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
1898 1899
}

1900 1901
static int scrub_add_page_to_rd_bio(struct scrub_ctx *sctx,
				    struct scrub_page *spage)
A
Arne Jansen 已提交
1902
{
1903
	struct scrub_block *sblock = spage->sblock;
A
Arne Jansen 已提交
1904
	struct scrub_bio *sbio;
1905
	int ret;
A
Arne Jansen 已提交
1906 1907 1908 1909 1910

again:
	/*
	 * grab a fresh bio or wait for one to become available
	 */
1911 1912 1913 1914 1915 1916 1917 1918
	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
1919
		} else {
1920 1921
			spin_unlock(&sctx->list_lock);
			wait_event(sctx->list_wait, sctx->first_free != -1);
A
Arne Jansen 已提交
1922 1923
		}
	}
1924
	sbio = sctx->bios[sctx->curr];
1925
	if (sbio->page_count == 0) {
1926 1927
		struct bio *bio;

1928 1929
		sbio->physical = spage->physical;
		sbio->logical = spage->logical;
1930
		sbio->dev = spage->dev;
1931 1932
		bio = sbio->bio;
		if (!bio) {
1933
			bio = bio_alloc(GFP_NOFS, sctx->pages_per_rd_bio);
1934 1935 1936 1937
			if (!bio)
				return -ENOMEM;
			sbio->bio = bio;
		}
1938 1939 1940

		bio->bi_private = sbio;
		bio->bi_end_io = scrub_bio_end_io;
1941 1942
		bio->bi_bdev = sbio->dev->bdev;
		bio->bi_sector = sbio->physical >> 9;
1943
		sbio->err = 0;
1944 1945 1946
	} else if (sbio->physical + sbio->page_count * PAGE_SIZE !=
		   spage->physical ||
		   sbio->logical + sbio->page_count * PAGE_SIZE !=
1947 1948
		   spage->logical ||
		   sbio->dev != spage->dev) {
1949
		scrub_submit(sctx);
A
Arne Jansen 已提交
1950 1951
		goto again;
	}
1952

1953 1954 1955 1956 1957 1958 1959 1960
	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;
		}
1961
		scrub_submit(sctx);
1962 1963 1964
		goto again;
	}

1965
	scrub_block_get(sblock); /* one for the page added to the bio */
1966 1967
	atomic_inc(&sblock->outstanding_pages);
	sbio->page_count++;
1968
	if (sbio->page_count == sctx->pages_per_rd_bio)
1969
		scrub_submit(sctx);
1970 1971 1972 1973

	return 0;
}

1974
static int scrub_pages(struct scrub_ctx *sctx, u64 logical, u64 len,
1975
		       u64 physical, struct btrfs_device *dev, u64 flags,
1976 1977
		       u64 gen, int mirror_num, u8 *csum, int force,
		       u64 physical_for_dev_replace)
1978 1979 1980 1981 1982 1983
{
	struct scrub_block *sblock;
	int index;

	sblock = kzalloc(sizeof(*sblock), GFP_NOFS);
	if (!sblock) {
1984 1985 1986
		spin_lock(&sctx->stat_lock);
		sctx->stat.malloc_errors++;
		spin_unlock(&sctx->stat_lock);
1987
		return -ENOMEM;
A
Arne Jansen 已提交
1988
	}
1989

1990 1991
	/* one ref inside this function, plus one for each page added to
	 * a bio later on */
1992
	atomic_set(&sblock->ref_count, 1);
1993
	sblock->sctx = sctx;
1994 1995 1996
	sblock->no_io_error_seen = 1;

	for (index = 0; len > 0; index++) {
1997
		struct scrub_page *spage;
1998 1999
		u64 l = min_t(u64, len, PAGE_SIZE);

2000 2001 2002
		spage = kzalloc(sizeof(*spage), GFP_NOFS);
		if (!spage) {
leave_nomem:
2003 2004 2005
			spin_lock(&sctx->stat_lock);
			sctx->stat.malloc_errors++;
			spin_unlock(&sctx->stat_lock);
2006
			scrub_block_put(sblock);
2007 2008
			return -ENOMEM;
		}
2009 2010 2011
		BUG_ON(index >= SCRUB_MAX_PAGES_PER_BLOCK);
		scrub_page_get(spage);
		sblock->pagev[index] = spage;
2012
		spage->sblock = sblock;
2013
		spage->dev = dev;
2014 2015 2016 2017
		spage->flags = flags;
		spage->generation = gen;
		spage->logical = logical;
		spage->physical = physical;
2018
		spage->physical_for_dev_replace = physical_for_dev_replace;
2019 2020 2021
		spage->mirror_num = mirror_num;
		if (csum) {
			spage->have_csum = 1;
2022
			memcpy(spage->csum, csum, sctx->csum_size);
2023 2024 2025 2026
		} else {
			spage->have_csum = 0;
		}
		sblock->page_count++;
2027 2028 2029
		spage->page = alloc_page(GFP_NOFS);
		if (!spage->page)
			goto leave_nomem;
2030 2031 2032
		len -= l;
		logical += l;
		physical += l;
2033
		physical_for_dev_replace += l;
2034 2035
	}

2036
	WARN_ON(sblock->page_count == 0);
2037
	for (index = 0; index < sblock->page_count; index++) {
2038
		struct scrub_page *spage = sblock->pagev[index];
2039 2040
		int ret;

2041
		ret = scrub_add_page_to_rd_bio(sctx, spage);
2042 2043
		if (ret) {
			scrub_block_put(sblock);
2044
			return ret;
2045
		}
2046
	}
A
Arne Jansen 已提交
2047

2048
	if (force)
2049
		scrub_submit(sctx);
A
Arne Jansen 已提交
2050

2051 2052
	/* last one frees, either here or in bio completion for last page */
	scrub_block_put(sblock);
A
Arne Jansen 已提交
2053 2054 2055
	return 0;
}

2056 2057 2058
static void scrub_bio_end_io(struct bio *bio, int err)
{
	struct scrub_bio *sbio = bio->bi_private;
2059
	struct btrfs_fs_info *fs_info = sbio->dev->dev_root->fs_info;
2060 2061 2062 2063 2064 2065 2066 2067 2068 2069

	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);
2070
	struct scrub_ctx *sctx = sbio->sctx;
2071 2072
	int i;

2073
	BUG_ON(sbio->page_count > SCRUB_PAGES_PER_RD_BIO);
2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094
	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;
2095 2096 2097 2098
	spin_lock(&sctx->list_lock);
	sbio->next_free = sctx->first_free;
	sctx->first_free = sbio->index;
	spin_unlock(&sctx->list_lock);
2099 2100 2101 2102 2103 2104 2105 2106

	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);
	}

2107
	scrub_pending_bio_dec(sctx);
2108 2109 2110 2111
}

static void scrub_block_complete(struct scrub_block *sblock)
{
2112
	if (!sblock->no_io_error_seen) {
2113
		scrub_handle_errored_block(sblock);
2114 2115 2116 2117 2118 2119 2120 2121 2122
	} 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);
	}
2123 2124
}

2125
static int scrub_find_csum(struct scrub_ctx *sctx, u64 logical, u64 len,
A
Arne Jansen 已提交
2126 2127 2128 2129 2130 2131 2132
			   u8 *csum)
{
	struct btrfs_ordered_sum *sum = NULL;
	int ret = 0;
	unsigned long i;
	unsigned long num_sectors;

2133 2134
	while (!list_empty(&sctx->csum_list)) {
		sum = list_first_entry(&sctx->csum_list,
A
Arne Jansen 已提交
2135 2136 2137 2138 2139 2140
				       struct btrfs_ordered_sum, list);
		if (sum->bytenr > logical)
			return 0;
		if (sum->bytenr + sum->len > logical)
			break;

2141
		++sctx->stat.csum_discards;
A
Arne Jansen 已提交
2142 2143 2144 2145 2146 2147 2148
		list_del(&sum->list);
		kfree(sum);
		sum = NULL;
	}
	if (!sum)
		return 0;

2149
	num_sectors = sum->len / sctx->sectorsize;
A
Arne Jansen 已提交
2150 2151
	for (i = 0; i < num_sectors; ++i) {
		if (sum->sums[i].bytenr == logical) {
2152
			memcpy(csum, &sum->sums[i].sum, sctx->csum_size);
A
Arne Jansen 已提交
2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164
			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 */
2165
static int scrub_extent(struct scrub_ctx *sctx, u64 logical, u64 len,
2166
			u64 physical, struct btrfs_device *dev, u64 flags,
2167
			u64 gen, int mirror_num, u64 physical_for_dev_replace)
A
Arne Jansen 已提交
2168 2169 2170
{
	int ret;
	u8 csum[BTRFS_CSUM_SIZE];
2171 2172 2173
	u32 blocksize;

	if (flags & BTRFS_EXTENT_FLAG_DATA) {
2174 2175 2176 2177 2178
		blocksize = sctx->sectorsize;
		spin_lock(&sctx->stat_lock);
		sctx->stat.data_extents_scrubbed++;
		sctx->stat.data_bytes_scrubbed += len;
		spin_unlock(&sctx->stat_lock);
2179
	} else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
2180
		WARN_ON(sctx->nodesize != sctx->leafsize);
2181 2182 2183 2184 2185
		blocksize = sctx->nodesize;
		spin_lock(&sctx->stat_lock);
		sctx->stat.tree_extents_scrubbed++;
		sctx->stat.tree_bytes_scrubbed += len;
		spin_unlock(&sctx->stat_lock);
2186
	} else {
2187
		blocksize = sctx->sectorsize;
2188
		WARN_ON(1);
2189
	}
A
Arne Jansen 已提交
2190 2191

	while (len) {
2192
		u64 l = min_t(u64, len, blocksize);
A
Arne Jansen 已提交
2193 2194 2195 2196
		int have_csum = 0;

		if (flags & BTRFS_EXTENT_FLAG_DATA) {
			/* push csums to sbio */
2197
			have_csum = scrub_find_csum(sctx, logical, l, csum);
A
Arne Jansen 已提交
2198
			if (have_csum == 0)
2199
				++sctx->stat.no_csum;
2200 2201 2202 2203 2204 2205
			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
2206
		}
2207
		ret = scrub_pages(sctx, logical, l, physical, dev, flags, gen,
2208 2209 2210
				  mirror_num, have_csum ? csum : NULL, 0,
				  physical_for_dev_replace);
behind_scrub_pages:
A
Arne Jansen 已提交
2211 2212 2213 2214 2215
		if (ret)
			return ret;
		len -= l;
		logical += l;
		physical += l;
2216
		physical_for_dev_replace += l;
A
Arne Jansen 已提交
2217 2218 2219 2220
	}
	return 0;
}

2221
static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
2222 2223
					   struct map_lookup *map,
					   struct btrfs_device *scrub_dev,
2224 2225
					   int num, u64 base, u64 length,
					   int is_dev_replace)
A
Arne Jansen 已提交
2226 2227
{
	struct btrfs_path *path;
2228
	struct btrfs_fs_info *fs_info = sctx->dev_root->fs_info;
A
Arne Jansen 已提交
2229 2230 2231
	struct btrfs_root *root = fs_info->extent_root;
	struct btrfs_root *csum_root = fs_info->csum_root;
	struct btrfs_extent_item *extent;
2232
	struct blk_plug plug;
A
Arne Jansen 已提交
2233 2234 2235 2236 2237 2238 2239 2240
	u64 flags;
	int ret;
	int slot;
	u64 nstripes;
	struct extent_buffer *l;
	struct btrfs_key key;
	u64 physical;
	u64 logical;
L
Liu Bo 已提交
2241
	u64 logic_end;
A
Arne Jansen 已提交
2242
	u64 generation;
2243
	int mirror_num;
A
Arne Jansen 已提交
2244 2245 2246 2247
	struct reada_control *reada1;
	struct reada_control *reada2;
	struct btrfs_key key_start;
	struct btrfs_key key_end;
A
Arne Jansen 已提交
2248 2249
	u64 increment = map->stripe_len;
	u64 offset;
2250 2251 2252 2253 2254
	u64 extent_logical;
	u64 extent_physical;
	u64 extent_len;
	struct btrfs_device *extent_dev;
	int extent_mirror_num;
L
Liu Bo 已提交
2255
	int stop_loop;
A
Arne Jansen 已提交
2256

D
David Woodhouse 已提交
2257 2258 2259 2260 2261 2262 2263
	if (map->type & (BTRFS_BLOCK_GROUP_RAID5 |
			 BTRFS_BLOCK_GROUP_RAID6)) {
		if (num >= nr_data_stripes(map)) {
			return 0;
		}
	}

A
Arne Jansen 已提交
2264 2265 2266 2267 2268 2269
	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;
2270
		mirror_num = 1;
A
Arne Jansen 已提交
2271 2272 2273 2274
	} 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;
2275
		mirror_num = num % map->sub_stripes + 1;
A
Arne Jansen 已提交
2276 2277
	} else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
		increment = map->stripe_len;
2278
		mirror_num = num % map->num_stripes + 1;
A
Arne Jansen 已提交
2279 2280
	} else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
		increment = map->stripe_len;
2281
		mirror_num = num % map->num_stripes + 1;
A
Arne Jansen 已提交
2282 2283
	} else {
		increment = map->stripe_len;
2284
		mirror_num = 1;
A
Arne Jansen 已提交
2285 2286 2287 2288 2289 2290
	}

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

2291 2292 2293 2294 2295
	/*
	 * 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
2296 2297 2298 2299
	path->search_commit_root = 1;
	path->skip_locking = 1;

	/*
A
Arne Jansen 已提交
2300 2301 2302
	 * 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
2303 2304 2305
	 */
	logical = base + offset;

2306
	wait_event(sctx->list_wait,
2307
		   atomic_read(&sctx->bios_in_flight) == 0);
A
Arne Jansen 已提交
2308 2309 2310 2311 2312 2313 2314 2315
	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;
2316 2317
	key_end.type = BTRFS_METADATA_ITEM_KEY;
	key_end.offset = (u64)-1;
A
Arne Jansen 已提交
2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338
	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
2339
	}
A
Arne Jansen 已提交
2340 2341 2342
	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
2343 2344 2345 2346 2347

	/*
	 * collect all data csums for the stripe to avoid seeking during
	 * the scrub. This might currently (crc32) end up to be about 1MB
	 */
2348
	blk_start_plug(&plug);
A
Arne Jansen 已提交
2349 2350 2351 2352

	/*
	 * now find all extents for each stripe and scrub them
	 */
A
Arne Jansen 已提交
2353 2354
	logical = base + offset;
	physical = map->stripes[num].physical;
L
Liu Bo 已提交
2355
	logic_end = logical + increment * nstripes;
A
Arne Jansen 已提交
2356
	ret = 0;
L
Liu Bo 已提交
2357
	while (logical < logic_end) {
A
Arne Jansen 已提交
2358 2359 2360 2361
		/*
		 * canceled?
		 */
		if (atomic_read(&fs_info->scrub_cancel_req) ||
2362
		    atomic_read(&sctx->cancel_req)) {
A
Arne Jansen 已提交
2363 2364 2365 2366 2367 2368 2369 2370
			ret = -ECANCELED;
			goto out;
		}
		/*
		 * check to see if we have to pause
		 */
		if (atomic_read(&fs_info->scrub_pause_req)) {
			/* push queued extents */
2371
			atomic_set(&sctx->wr_ctx.flush_all_writes, 1);
2372
			scrub_submit(sctx);
2373 2374 2375
			mutex_lock(&sctx->wr_ctx.wr_lock);
			scrub_wr_submit(sctx);
			mutex_unlock(&sctx->wr_ctx.wr_lock);
2376
			wait_event(sctx->list_wait,
2377
				   atomic_read(&sctx->bios_in_flight) == 0);
2378
			atomic_set(&sctx->wr_ctx.flush_all_writes, 0);
A
Arne Jansen 已提交
2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394
			atomic_inc(&fs_info->scrubs_paused);
			wake_up(&fs_info->scrub_pause_wait);
			mutex_lock(&fs_info->scrub_lock);
			while (atomic_read(&fs_info->scrub_pause_req)) {
				mutex_unlock(&fs_info->scrub_lock);
				wait_event(fs_info->scrub_pause_wait,
				   atomic_read(&fs_info->scrub_pause_req) == 0);
				mutex_lock(&fs_info->scrub_lock);
			}
			atomic_dec(&fs_info->scrubs_paused);
			mutex_unlock(&fs_info->scrub_lock);
			wake_up(&fs_info->scrub_pause_wait);
		}

		key.objectid = logical;
		key.type = BTRFS_EXTENT_ITEM_KEY;
L
Liu Bo 已提交
2395
		key.offset = (u64)-1;
A
Arne Jansen 已提交
2396 2397 2398 2399

		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
		if (ret < 0)
			goto out;
2400

2401
		if (ret > 0) {
A
Arne Jansen 已提交
2402 2403 2404 2405
			ret = btrfs_previous_item(root, path, 0,
						  BTRFS_EXTENT_ITEM_KEY);
			if (ret < 0)
				goto out;
2406 2407 2408 2409 2410 2411 2412 2413 2414
			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
2415 2416
		}

L
Liu Bo 已提交
2417
		stop_loop = 0;
A
Arne Jansen 已提交
2418
		while (1) {
2419 2420
			u64 bytes;

A
Arne Jansen 已提交
2421 2422 2423 2424 2425 2426 2427 2428 2429
			l = path->nodes[0];
			slot = path->slots[0];
			if (slot >= btrfs_header_nritems(l)) {
				ret = btrfs_next_leaf(root, path);
				if (ret == 0)
					continue;
				if (ret < 0)
					goto out;

L
Liu Bo 已提交
2430
				stop_loop = 1;
A
Arne Jansen 已提交
2431 2432 2433 2434
				break;
			}
			btrfs_item_key_to_cpu(l, &key, slot);

2435 2436 2437 2438 2439 2440
			if (key.type == BTRFS_METADATA_ITEM_KEY)
				bytes = root->leafsize;
			else
				bytes = key.offset;

			if (key.objectid + bytes <= logical)
A
Arne Jansen 已提交
2441 2442
				goto next;

L
Liu Bo 已提交
2443 2444 2445
			if (key.type != BTRFS_EXTENT_ITEM_KEY &&
			    key.type != BTRFS_METADATA_ITEM_KEY)
				goto next;
A
Arne Jansen 已提交
2446

L
Liu Bo 已提交
2447 2448 2449 2450 2451 2452
			if (key.objectid >= logical + map->stripe_len) {
				/* out of this device extent */
				if (key.objectid >= logic_end)
					stop_loop = 1;
				break;
			}
A
Arne Jansen 已提交
2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468

			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;
			}

L
Liu Bo 已提交
2469 2470 2471 2472
again:
			extent_logical = key.objectid;
			extent_len = bytes;

A
Arne Jansen 已提交
2473 2474 2475
			/*
			 * trim extent to this stripe
			 */
L
Liu Bo 已提交
2476 2477 2478
			if (extent_logical < logical) {
				extent_len -= logical - extent_logical;
				extent_logical = logical;
A
Arne Jansen 已提交
2479
			}
L
Liu Bo 已提交
2480
			if (extent_logical + extent_len >
A
Arne Jansen 已提交
2481
			    logical + map->stripe_len) {
L
Liu Bo 已提交
2482 2483
				extent_len = logical + map->stripe_len -
					     extent_logical;
A
Arne Jansen 已提交
2484 2485
			}

L
Liu Bo 已提交
2486
			extent_physical = extent_logical - logical + physical;
2487 2488 2489 2490 2491 2492 2493
			extent_dev = scrub_dev;
			extent_mirror_num = mirror_num;
			if (is_dev_replace)
				scrub_remap_extent(fs_info, extent_logical,
						   extent_len, &extent_physical,
						   &extent_dev,
						   &extent_mirror_num);
L
Liu Bo 已提交
2494 2495 2496 2497 2498 2499 2500

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

2501 2502 2503
			ret = scrub_extent(sctx, extent_logical, extent_len,
					   extent_physical, extent_dev, flags,
					   generation, extent_mirror_num,
L
Liu Bo 已提交
2504
					   extent_physical);
A
Arne Jansen 已提交
2505 2506 2507
			if (ret)
				goto out;

L
Liu Bo 已提交
2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522
			if (extent_logical + extent_len <
			    key.objectid + bytes) {
				logical += increment;
				physical += map->stripe_len;

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

				if (logical >= logic_end) {
					stop_loop = 1;
					break;
				}
			}
A
Arne Jansen 已提交
2523 2524 2525
next:
			path->slots[0]++;
		}
C
Chris Mason 已提交
2526
		btrfs_release_path(path);
A
Arne Jansen 已提交
2527 2528
		logical += increment;
		physical += map->stripe_len;
2529
		spin_lock(&sctx->stat_lock);
L
Liu Bo 已提交
2530 2531 2532 2533 2534
		if (stop_loop)
			sctx->stat.last_physical = map->stripes[num].physical +
						   length;
		else
			sctx->stat.last_physical = physical;
2535
		spin_unlock(&sctx->stat_lock);
L
Liu Bo 已提交
2536 2537
		if (stop_loop)
			break;
A
Arne Jansen 已提交
2538
	}
2539
out:
A
Arne Jansen 已提交
2540
	/* push queued extents */
2541
	scrub_submit(sctx);
2542 2543 2544
	mutex_lock(&sctx->wr_ctx.wr_lock);
	scrub_wr_submit(sctx);
	mutex_unlock(&sctx->wr_ctx.wr_lock);
A
Arne Jansen 已提交
2545

2546
	blk_finish_plug(&plug);
A
Arne Jansen 已提交
2547 2548 2549 2550
	btrfs_free_path(path);
	return ret < 0 ? ret : 0;
}

2551
static noinline_for_stack int scrub_chunk(struct scrub_ctx *sctx,
2552 2553 2554
					  struct btrfs_device *scrub_dev,
					  u64 chunk_tree, u64 chunk_objectid,
					  u64 chunk_offset, u64 length,
2555
					  u64 dev_offset, int is_dev_replace)
A
Arne Jansen 已提交
2556 2557
{
	struct btrfs_mapping_tree *map_tree =
2558
		&sctx->dev_root->fs_info->mapping_tree;
A
Arne Jansen 已提交
2559 2560 2561
	struct map_lookup *map;
	struct extent_map *em;
	int i;
2562
	int ret = 0;
A
Arne Jansen 已提交
2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578

	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) {
2579
		if (map->stripes[i].dev->bdev == scrub_dev->bdev &&
2580
		    map->stripes[i].physical == dev_offset) {
2581
			ret = scrub_stripe(sctx, map, scrub_dev, i,
2582 2583
					   chunk_offset, length,
					   is_dev_replace);
A
Arne Jansen 已提交
2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594
			if (ret)
				goto out;
		}
	}
out:
	free_extent_map(em);

	return ret;
}

static noinline_for_stack
2595
int scrub_enumerate_chunks(struct scrub_ctx *sctx,
2596 2597
			   struct btrfs_device *scrub_dev, u64 start, u64 end,
			   int is_dev_replace)
A
Arne Jansen 已提交
2598 2599 2600
{
	struct btrfs_dev_extent *dev_extent = NULL;
	struct btrfs_path *path;
2601
	struct btrfs_root *root = sctx->dev_root;
A
Arne Jansen 已提交
2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612
	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;
2613
	struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
A
Arne Jansen 已提交
2614 2615 2616 2617 2618 2619 2620 2621 2622

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

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

2623
	key.objectid = scrub_dev->devid;
A
Arne Jansen 已提交
2624 2625 2626 2627 2628 2629
	key.offset = 0ull;
	key.type = BTRFS_DEV_EXTENT_KEY;

	while (1) {
		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
		if (ret < 0)
2630 2631 2632 2633 2634 2635 2636 2637 2638
			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
2639 2640 2641 2642 2643 2644

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

		btrfs_item_key_to_cpu(l, &found_key, slot);

2645
		if (found_key.objectid != scrub_dev->devid)
A
Arne Jansen 已提交
2646 2647
			break;

2648
		if (btrfs_key_type(&found_key) != BTRFS_DEV_EXTENT_KEY)
A
Arne Jansen 已提交
2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659 2660 2661
			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
2662
			btrfs_release_path(path);
A
Arne Jansen 已提交
2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676
			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;
2677
			break;
A
Arne Jansen 已提交
2678
		}
2679 2680 2681
		dev_replace->cursor_right = found_key.offset + length;
		dev_replace->cursor_left = found_key.offset;
		dev_replace->item_needs_writeback = 1;
2682
		ret = scrub_chunk(sctx, scrub_dev, chunk_tree, chunk_objectid,
2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714 2715 2716 2717 2718 2719 2720 2721 2722
				  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
2723 2724 2725
		btrfs_put_block_group(cache);
		if (ret)
			break;
2726 2727
		if (is_dev_replace &&
		    atomic64_read(&dev_replace->num_write_errors) > 0) {
2728 2729 2730 2731 2732 2733 2734
			ret = -EIO;
			break;
		}
		if (sctx->stat.malloc_errors > 0) {
			ret = -ENOMEM;
			break;
		}
A
Arne Jansen 已提交
2735 2736

		key.offset = found_key.offset + length;
C
Chris Mason 已提交
2737
		btrfs_release_path(path);
A
Arne Jansen 已提交
2738 2739 2740
	}

	btrfs_free_path(path);
2741 2742 2743 2744 2745 2746

	/*
	 * 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
2747 2748
}

2749 2750
static noinline_for_stack int scrub_supers(struct scrub_ctx *sctx,
					   struct btrfs_device *scrub_dev)
A
Arne Jansen 已提交
2751 2752 2753 2754 2755
{
	int	i;
	u64	bytenr;
	u64	gen;
	int	ret;
2756
	struct btrfs_root *root = sctx->dev_root;
A
Arne Jansen 已提交
2757

2758
	if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
2759 2760
		return -EIO;

A
Arne Jansen 已提交
2761 2762 2763 2764
	gen = root->fs_info->last_trans_committed;

	for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
		bytenr = btrfs_sb_offset(i);
2765
		if (bytenr + BTRFS_SUPER_INFO_SIZE > scrub_dev->total_bytes)
A
Arne Jansen 已提交
2766 2767
			break;

2768
		ret = scrub_pages(sctx, bytenr, BTRFS_SUPER_INFO_SIZE, bytenr,
2769
				  scrub_dev, BTRFS_EXTENT_FLAG_SUPER, gen, i,
2770
				  NULL, 1, bytenr);
A
Arne Jansen 已提交
2771 2772 2773
		if (ret)
			return ret;
	}
2774
	wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0);
A
Arne Jansen 已提交
2775 2776 2777 2778 2779 2780 2781

	return 0;
}

/*
 * get a reference count on fs_info->scrub_workers. start worker if necessary
 */
2782 2783
static noinline_for_stack int scrub_workers_get(struct btrfs_fs_info *fs_info,
						int is_dev_replace)
A
Arne Jansen 已提交
2784
{
2785
	int ret = 0;
A
Arne Jansen 已提交
2786 2787

	mutex_lock(&fs_info->scrub_lock);
A
Arne Jansen 已提交
2788
	if (fs_info->scrub_workers_refcnt == 0) {
2789 2790 2791 2792 2793 2794 2795
		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
2796
		fs_info->scrub_workers.idle_thresh = 4;
2797 2798 2799
		ret = btrfs_start_workers(&fs_info->scrub_workers);
		if (ret)
			goto out;
2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813
		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
2814
	}
A
Arne Jansen 已提交
2815
	++fs_info->scrub_workers_refcnt;
2816
out:
A
Arne Jansen 已提交
2817 2818
	mutex_unlock(&fs_info->scrub_lock);

2819
	return ret;
A
Arne Jansen 已提交
2820 2821
}

2822
static noinline_for_stack void scrub_workers_put(struct btrfs_fs_info *fs_info)
A
Arne Jansen 已提交
2823 2824
{
	mutex_lock(&fs_info->scrub_lock);
2825
	if (--fs_info->scrub_workers_refcnt == 0) {
A
Arne Jansen 已提交
2826
		btrfs_stop_workers(&fs_info->scrub_workers);
2827 2828 2829
		btrfs_stop_workers(&fs_info->scrub_wr_completion_workers);
		btrfs_stop_workers(&fs_info->scrub_nocow_workers);
	}
A
Arne Jansen 已提交
2830 2831 2832 2833
	WARN_ON(fs_info->scrub_workers_refcnt < 0);
	mutex_unlock(&fs_info->scrub_lock);
}

2834 2835
int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start,
		    u64 end, struct btrfs_scrub_progress *progress,
2836
		    int readonly, int is_dev_replace)
A
Arne Jansen 已提交
2837
{
2838
	struct scrub_ctx *sctx;
A
Arne Jansen 已提交
2839 2840 2841
	int ret;
	struct btrfs_device *dev;

2842
	if (btrfs_fs_closing(fs_info))
A
Arne Jansen 已提交
2843 2844 2845 2846 2847
		return -EINVAL;

	/*
	 * check some assumptions
	 */
2848
	if (fs_info->chunk_root->nodesize != fs_info->chunk_root->leafsize) {
2849 2850
		printk(KERN_ERR
		       "btrfs_scrub: size assumption nodesize == leafsize (%d == %d) fails\n",
2851 2852
		       fs_info->chunk_root->nodesize,
		       fs_info->chunk_root->leafsize);
2853 2854 2855
		return -EINVAL;
	}

2856
	if (fs_info->chunk_root->nodesize > BTRFS_STRIPE_LEN) {
2857 2858 2859 2860 2861 2862 2863
		/*
		 * 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",
2864
		       fs_info->chunk_root->nodesize, BTRFS_STRIPE_LEN);
2865 2866 2867
		return -EINVAL;
	}

2868
	if (fs_info->chunk_root->sectorsize != PAGE_SIZE) {
2869 2870 2871
		/* not supported for data w/o checksums */
		printk(KERN_ERR
		       "btrfs_scrub: size assumption sectorsize != PAGE_SIZE (%d != %lld) fails\n",
2872 2873
		       fs_info->chunk_root->sectorsize,
		       (unsigned long long)PAGE_SIZE);
A
Arne Jansen 已提交
2874 2875 2876
		return -EINVAL;
	}

2877 2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892
	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;
	}

2893
	ret = scrub_workers_get(fs_info, is_dev_replace);
A
Arne Jansen 已提交
2894 2895 2896
	if (ret)
		return ret;

2897 2898
	mutex_lock(&fs_info->fs_devices->device_list_mutex);
	dev = btrfs_find_device(fs_info, devid, NULL, NULL);
2899
	if (!dev || (dev->missing && !is_dev_replace)) {
2900 2901
		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
		scrub_workers_put(fs_info);
A
Arne Jansen 已提交
2902 2903 2904 2905
		return -ENODEV;
	}
	mutex_lock(&fs_info->scrub_lock);

2906
	if (!dev->in_fs_metadata || dev->is_tgtdev_for_dev_replace) {
A
Arne Jansen 已提交
2907
		mutex_unlock(&fs_info->scrub_lock);
2908 2909 2910
		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
		scrub_workers_put(fs_info);
		return -EIO;
A
Arne Jansen 已提交
2911 2912
	}

2913 2914 2915 2916 2917
	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
2918
		mutex_unlock(&fs_info->scrub_lock);
2919 2920
		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
		scrub_workers_put(fs_info);
A
Arne Jansen 已提交
2921 2922
		return -EINPROGRESS;
	}
2923
	btrfs_dev_replace_unlock(&fs_info->dev_replace);
2924
	sctx = scrub_setup_ctx(dev, is_dev_replace);
2925
	if (IS_ERR(sctx)) {
A
Arne Jansen 已提交
2926
		mutex_unlock(&fs_info->scrub_lock);
2927 2928
		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
		scrub_workers_put(fs_info);
2929
		return PTR_ERR(sctx);
A
Arne Jansen 已提交
2930
	}
2931 2932
	sctx->readonly = readonly;
	dev->scrub_device = sctx;
A
Arne Jansen 已提交
2933 2934 2935

	atomic_inc(&fs_info->scrubs_running);
	mutex_unlock(&fs_info->scrub_lock);
2936
	mutex_unlock(&fs_info->fs_devices->device_list_mutex);
A
Arne Jansen 已提交
2937

2938 2939 2940 2941 2942
	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
2943 2944

	if (!ret)
2945 2946
		ret = scrub_enumerate_chunks(sctx, dev, start, end,
					     is_dev_replace);
A
Arne Jansen 已提交
2947

2948
	wait_event(sctx->list_wait, atomic_read(&sctx->bios_in_flight) == 0);
A
Arne Jansen 已提交
2949 2950 2951
	atomic_dec(&fs_info->scrubs_running);
	wake_up(&fs_info->scrub_pause_wait);

2952
	wait_event(sctx->list_wait, atomic_read(&sctx->workers_pending) == 0);
2953

A
Arne Jansen 已提交
2954
	if (progress)
2955
		memcpy(progress, &sctx->stat, sizeof(*progress));
A
Arne Jansen 已提交
2956 2957 2958 2959 2960

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

2961
	scrub_free_ctx(sctx);
2962
	scrub_workers_put(fs_info);
A
Arne Jansen 已提交
2963 2964 2965 2966

	return ret;
}

2967
void btrfs_scrub_pause(struct btrfs_root *root)
A
Arne Jansen 已提交
2968 2969 2970 2971 2972 2973 2974 2975 2976 2977 2978 2979 2980 2981 2982 2983
{
	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);
}

2984
void btrfs_scrub_continue(struct btrfs_root *root)
A
Arne Jansen 已提交
2985 2986 2987 2988 2989 2990 2991
{
	struct btrfs_fs_info *fs_info = root->fs_info;

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

2992
void btrfs_scrub_pause_super(struct btrfs_root *root)
A
Arne Jansen 已提交
2993 2994 2995 2996
{
	down_write(&root->fs_info->scrub_super_lock);
}

2997
void btrfs_scrub_continue_super(struct btrfs_root *root)
A
Arne Jansen 已提交
2998 2999 3000 3001
{
	up_write(&root->fs_info->scrub_super_lock);
}

3002
int btrfs_scrub_cancel(struct btrfs_fs_info *fs_info)
A
Arne Jansen 已提交
3003 3004 3005 3006 3007 3008 3009 3010 3011 3012 3013 3014 3015 3016 3017 3018 3019 3020 3021 3022
{
	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;
}

3023 3024
int btrfs_scrub_cancel_dev(struct btrfs_fs_info *fs_info,
			   struct btrfs_device *dev)
3025
{
3026
	struct scrub_ctx *sctx;
A
Arne Jansen 已提交
3027 3028

	mutex_lock(&fs_info->scrub_lock);
3029 3030
	sctx = dev->scrub_device;
	if (!sctx) {
A
Arne Jansen 已提交
3031 3032 3033
		mutex_unlock(&fs_info->scrub_lock);
		return -ENOTCONN;
	}
3034
	atomic_inc(&sctx->cancel_req);
A
Arne Jansen 已提交
3035 3036 3037 3038 3039 3040 3041 3042 3043 3044
	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
3045

A
Arne Jansen 已提交
3046 3047 3048 3049
int btrfs_scrub_progress(struct btrfs_root *root, u64 devid,
			 struct btrfs_scrub_progress *progress)
{
	struct btrfs_device *dev;
3050
	struct scrub_ctx *sctx = NULL;
A
Arne Jansen 已提交
3051 3052

	mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
3053
	dev = btrfs_find_device(root->fs_info, devid, NULL, NULL);
A
Arne Jansen 已提交
3054
	if (dev)
3055 3056 3057
		sctx = dev->scrub_device;
	if (sctx)
		memcpy(progress, &sctx->stat, sizeof(*progress));
A
Arne Jansen 已提交
3058 3059
	mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);

3060
	return dev ? (sctx ? 0 : -ENOTCONN) : -ENODEV;
A
Arne Jansen 已提交
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

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;
3216
	int srcu_index;
3217 3218 3219 3220

	key.objectid = root;
	key.type = BTRFS_ROOT_ITEM_KEY;
	key.offset = (u64)-1;
3221 3222 3223

	srcu_index = srcu_read_lock(&fs_info->subvol_srcu);

3224
	local_root = btrfs_read_fs_root_no_name(fs_info, &key);
3225 3226
	if (IS_ERR(local_root)) {
		srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
3227
		return PTR_ERR(local_root);
3228
	}
3229 3230 3231 3232 3233

	key.type = BTRFS_INODE_ITEM_KEY;
	key.objectid = inum;
	key.offset = 0;
	inode = btrfs_iget(fs_info->sb, &key, local_root, NULL);
3234
	srcu_read_unlock(&fs_info->subvol_srcu, srcu_index);
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 3287 3288 3289 3290 3291 3292 3293 3294 3295 3296 3297 3298 3299 3300 3301 3302 3303 3304 3305 3306 3307 3308 3309 3310 3311 3312 3313 3314 3315 3316 3317 3318 3319 3320 3321 3322 3323 3324 3325 3326 3327 3328 3329 3330 3331 3332 3333 3334 3335 3336 3337
	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;
}