scrub.c 44.0 KB
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/*
 * Copyright (C) 2011 STRATO.  All rights reserved.
 *
 * 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 "check-integrity.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
 */

struct scrub_dev;

#define SCRUB_PAGES_PER_BIO	16	/* 64k per bio */
#define SCRUB_BIOS_PER_DEV	16	/* 1 MB per device in flight */

struct scrub_page {
	u64			flags;  /* extent flags */
	u64			generation;
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	int			mirror_num;
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	int			have_csum;
	u8			csum[BTRFS_CSUM_SIZE];
};

struct scrub_bio {
	int			index;
	struct scrub_dev	*sdev;
	struct bio		*bio;
	int			err;
	u64			logical;
	u64			physical;
	struct scrub_page	spag[SCRUB_PAGES_PER_BIO];
	u64			count;
	int			next_free;
	struct btrfs_work	work;
};

struct scrub_dev {
	struct scrub_bio	*bios[SCRUB_BIOS_PER_DEV];
	struct btrfs_device	*dev;
	int			first_free;
	int			curr;
	atomic_t		in_flight;
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	atomic_t		fixup_cnt;
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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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	/*
	 * statistics
	 */
	struct btrfs_scrub_progress stat;
	spinlock_t		stat_lock;
};

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struct scrub_fixup_nodatasum {
	struct scrub_dev	*sdev;
	u64			logical;
	struct btrfs_root	*root;
	struct btrfs_work	work;
	int			mirror_num;
};

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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_bio_end_io(struct bio *bio, int err);
static void scrub_checksum(struct btrfs_work *work);
static int scrub_checksum_data(struct scrub_dev *sdev,
			       struct scrub_page *spag, void *buffer);
static int scrub_checksum_tree_block(struct scrub_dev *sdev,
				     struct scrub_page *spag, u64 logical,
				     void *buffer);
static int scrub_checksum_super(struct scrub_bio *sbio, void *buffer);
static int scrub_fixup_check(struct scrub_bio *sbio, int ix);
static void scrub_fixup_end_io(struct bio *bio, int err);
static int scrub_fixup_io(int rw, struct block_device *bdev, sector_t sector,
			  struct page *page);
static void scrub_fixup(struct scrub_bio *sbio, int ix);


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

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static void scrub_free_bio(struct bio *bio)
{
	int i;
	struct page *last_page = NULL;

	if (!bio)
		return;

	for (i = 0; i < bio->bi_vcnt; ++i) {
		if (bio->bi_io_vec[i].bv_page == last_page)
			continue;
		last_page = bio->bi_io_vec[i].bv_page;
		__free_page(last_page);
	}
	bio_put(bio);
}

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static noinline_for_stack void scrub_free_dev(struct scrub_dev *sdev)
{
	int i;

	if (!sdev)
		return;

	for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) {
		struct scrub_bio *sbio = sdev->bios[i];

		if (!sbio)
			break;

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		scrub_free_bio(sbio->bio);
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		kfree(sbio);
	}

	scrub_free_csums(sdev);
	kfree(sdev);
}

static noinline_for_stack
struct scrub_dev *scrub_setup_dev(struct btrfs_device *dev)
{
	struct scrub_dev *sdev;
	int		i;
	struct btrfs_fs_info *fs_info = dev->dev_root->fs_info;

	sdev = kzalloc(sizeof(*sdev), GFP_NOFS);
	if (!sdev)
		goto nomem;
	sdev->dev = dev;
	for (i = 0; i < SCRUB_BIOS_PER_DEV; ++i) {
		struct scrub_bio *sbio;

		sbio = kzalloc(sizeof(*sbio), GFP_NOFS);
		if (!sbio)
			goto nomem;
		sdev->bios[i] = sbio;

		sbio->index = i;
		sbio->sdev = sdev;
		sbio->count = 0;
		sbio->work.func = scrub_checksum;

		if (i != SCRUB_BIOS_PER_DEV-1)
			sdev->bios[i]->next_free = i + 1;
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		else
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			sdev->bios[i]->next_free = -1;
	}
	sdev->first_free = 0;
	sdev->curr = -1;
	atomic_set(&sdev->in_flight, 0);
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	atomic_set(&sdev->fixup_cnt, 0);
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	atomic_set(&sdev->cancel_req, 0);
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	sdev->csum_size = btrfs_super_csum_size(fs_info->super_copy);
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	INIT_LIST_HEAD(&sdev->csum_list);

	spin_lock_init(&sdev->list_lock);
	spin_lock_init(&sdev->stat_lock);
	init_waitqueue_head(&sdev->list_wait);
	return sdev;

nomem:
	scrub_free_dev(sdev);
	return ERR_PTR(-ENOMEM);
}

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static int scrub_print_warning_inode(u64 inum, u64 offset, u64 root, void *ctx)
{
	u64 isize;
	u32 nlink;
	int ret;
	int i;
	struct extent_buffer *eb;
	struct btrfs_inode_item *inode_item;
	struct scrub_warning *swarn = ctx;
	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)
		printk(KERN_WARNING "btrfs: %s at logical %llu on dev "
			"%s, sector %llu, root %llu, inode %llu, offset %llu, "
			"length %llu, links %u (path: %s)\n", swarn->errstr,
			swarn->logical, swarn->dev->name,
			(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:
	printk(KERN_WARNING "btrfs: %s at logical %llu on dev "
		"%s, sector %llu, root %llu, inode %llu, offset %llu: path "
		"resolving failed with ret=%d\n", swarn->errstr,
		swarn->logical, swarn->dev->name,
		(unsigned long long)swarn->sector, root, inum, offset, ret);

	free_ipath(ipath);
	return 0;
}

static void scrub_print_warning(const char *errstr, struct scrub_bio *sbio,
				int ix)
{
	struct btrfs_device *dev = sbio->sdev->dev;
	struct btrfs_fs_info *fs_info = dev->dev_root->fs_info;
	struct btrfs_path *path;
	struct btrfs_key found_key;
	struct extent_buffer *eb;
	struct btrfs_extent_item *ei;
	struct scrub_warning swarn;
	u32 item_size;
	int ret;
	u64 ref_root;
	u8 ref_level;
	unsigned long ptr = 0;
	const int bufsize = 4096;
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	u64 extent_item_pos;
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	path = btrfs_alloc_path();

	swarn.scratch_buf = kmalloc(bufsize, GFP_NOFS);
	swarn.msg_buf = kmalloc(bufsize, GFP_NOFS);
	swarn.sector = (sbio->physical + ix * PAGE_SIZE) >> 9;
	swarn.logical = sbio->logical + ix * PAGE_SIZE;
	swarn.errstr = errstr;
	swarn.dev = dev;
	swarn.msg_bufsize = bufsize;
	swarn.scratch_bufsize = bufsize;

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

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

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

	eb = path->nodes[0];
	ei = btrfs_item_ptr(eb, path->slots[0], struct btrfs_extent_item);
	item_size = btrfs_item_size_nr(eb, path->slots[0]);
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	btrfs_release_path(path);
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	if (ret & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
		do {
			ret = tree_backref_for_extent(&ptr, eb, ei, item_size,
							&ref_root, &ref_level);
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			printk(KERN_WARNING
				"btrfs: %s at logical %llu on dev %s, "
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				"sector %llu: metadata %s (level %d) in tree "
				"%llu\n", errstr, swarn.logical, dev->name,
				(unsigned long long)swarn.sector,
				ref_level ? "node" : "leaf",
				ret < 0 ? -1 : ref_level,
				ret < 0 ? -1 : ref_root);
		} while (ret != 1);
	} else {
		swarn.path = path;
		iterate_extent_inodes(fs_info, path, found_key.objectid,
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					extent_item_pos,
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					scrub_print_warning_inode, &swarn);
	}

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

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static int scrub_fixup_readpage(u64 inum, u64 offset, u64 root, void *ctx)
{
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	struct page *page = NULL;
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	unsigned long index;
	struct scrub_fixup_nodatasum *fixup = ctx;
	int ret;
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	int corrected = 0;
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	struct btrfs_key key;
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	struct inode *inode = NULL;
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	u64 end = offset + PAGE_SIZE - 1;
	struct btrfs_root *local_root;

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

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

	index = offset >> PAGE_CACHE_SHIFT;

	page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
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	if (!page) {
		ret = -ENOMEM;
		goto out;
	}

	if (PageUptodate(page)) {
		struct btrfs_mapping_tree *map_tree;
		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;
		}
		map_tree = &BTRFS_I(inode)->root->fs_info->mapping_tree;
		ret = repair_io_failure(map_tree, offset, PAGE_SIZE,
					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);
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	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;
	struct scrub_dev *sdev;
	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);
	sdev = fixup->sdev;
	fs_info = fixup->root->fs_info;

	path = btrfs_alloc_path();
	if (!path) {
		spin_lock(&sdev->stat_lock);
		++sdev->stat.malloc_errors;
		spin_unlock(&sdev->stat_lock);
		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);

	spin_lock(&sdev->stat_lock);
	++sdev->stat.corrected_errors;
	spin_unlock(&sdev->stat_lock);

out:
	if (trans && !IS_ERR(trans))
		btrfs_end_transaction(trans, fixup->root);
	if (uncorrectable) {
		spin_lock(&sdev->stat_lock);
		++sdev->stat.uncorrectable_errors;
		spin_unlock(&sdev->stat_lock);
		printk_ratelimited(KERN_ERR "btrfs: unable to fixup "
					"(nodatasum) error at logical %llu\n",
					fixup->logical);
	}

	btrfs_free_path(path);
	kfree(fixup);

	/* see caller 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(&sdev->fixup_cnt);
	wake_up(&fs_info->scrub_pause_wait);
	wake_up(&sdev->list_wait);
}

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/*
 * scrub_recheck_error gets called when either verification of the page
 * failed or the bio failed to read, e.g. with EIO. In the latter case,
 * recheck_error gets called for every page in the bio, even though only
 * one may be bad
 */
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static int scrub_recheck_error(struct scrub_bio *sbio, int ix)
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{
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	struct scrub_dev *sdev = sbio->sdev;
	u64 sector = (sbio->physical + ix * PAGE_SIZE) >> 9;
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	static DEFINE_RATELIMIT_STATE(_rs, DEFAULT_RATELIMIT_INTERVAL,
					DEFAULT_RATELIMIT_BURST);
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	if (sbio->err) {
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		if (scrub_fixup_io(READ, sbio->sdev->dev->bdev, sector,
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				   sbio->bio->bi_io_vec[ix].bv_page) == 0) {
			if (scrub_fixup_check(sbio, ix) == 0)
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				return 0;
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		}
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		if (__ratelimit(&_rs))
			scrub_print_warning("i/o error", sbio, ix);
	} else {
		if (__ratelimit(&_rs))
			scrub_print_warning("checksum error", sbio, ix);
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	}

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	spin_lock(&sdev->stat_lock);
	++sdev->stat.read_errors;
	spin_unlock(&sdev->stat_lock);

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	scrub_fixup(sbio, ix);
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	return 1;
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}

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static int scrub_fixup_check(struct scrub_bio *sbio, int ix)
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{
	int ret = 1;
	struct page *page;
	void *buffer;
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	u64 flags = sbio->spag[ix].flags;
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	page = sbio->bio->bi_io_vec[ix].bv_page;
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	buffer = kmap_atomic(page, KM_USER0);
	if (flags & BTRFS_EXTENT_FLAG_DATA) {
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		ret = scrub_checksum_data(sbio->sdev,
					  sbio->spag + ix, buffer);
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	} else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
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		ret = scrub_checksum_tree_block(sbio->sdev,
						sbio->spag + ix,
						sbio->logical + ix * PAGE_SIZE,
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						buffer);
	} else {
		WARN_ON(1);
	}
	kunmap_atomic(buffer, KM_USER0);

	return ret;
}

static void scrub_fixup_end_io(struct bio *bio, int err)
{
	complete((struct completion *)bio->bi_private);
}

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Ilya Dryomov 已提交
615
static void scrub_fixup(struct scrub_bio *sbio, int ix)
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Arne Jansen 已提交
616
{
I
Ilya Dryomov 已提交
617
	struct scrub_dev *sdev = sbio->sdev;
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618 619
	struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
	struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
620
	struct btrfs_bio *bbio = NULL;
621
	struct scrub_fixup_nodatasum *fixup;
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Ilya Dryomov 已提交
622
	u64 logical = sbio->logical + ix * PAGE_SIZE;
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623 624 625 626 627
	u64 length;
	int i;
	int ret;
	DECLARE_COMPLETION_ONSTACK(complete);

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628 629
	if ((sbio->spag[ix].flags & BTRFS_EXTENT_FLAG_DATA) &&
	    (sbio->spag[ix].have_csum == 0)) {
630 631 632 633 634 635 636
		fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
		if (!fixup)
			goto uncorrectable;
		fixup->sdev = sdev;
		fixup->logical = logical;
		fixup->root = fs_info->extent_root;
		fixup->mirror_num = sbio->spag[ix].mirror_num;
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		/*
638 639 640 641 642 643 644
		 * increment scrubs_running to prevent cancel requests from
		 * completing as long as a fixup 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 fixup worker
		 * as paused for all matters practical. effectively, we only
		 * avoid cancellation requests from completing.
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		 */
646 647 648 649 650 651 652 653
		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(&sdev->fixup_cnt);
		fixup->work.func = scrub_fixup_nodatasum;
		btrfs_queue_worker(&fs_info->scrub_workers, &fixup->work);
		return;
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	}

	length = PAGE_SIZE;
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	ret = btrfs_map_block(map_tree, REQ_WRITE, logical, &length,
658 659
			      &bbio, 0);
	if (ret || !bbio || length < PAGE_SIZE) {
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		printk(KERN_ERR
		       "scrub_fixup: btrfs_map_block failed us for %llu\n",
I
Ilya Dryomov 已提交
662
		       (unsigned long long)logical);
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663
		WARN_ON(1);
664
		kfree(bbio);
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		return;
	}

668
	if (bbio->num_stripes == 1)
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		/* there aren't any replicas */
		goto uncorrectable;

	/*
	 * first find a good copy
	 */
675
	for (i = 0; i < bbio->num_stripes; ++i) {
676
		if (i + 1 == sbio->spag[ix].mirror_num)
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			continue;

679 680
		if (scrub_fixup_io(READ, bbio->stripes[i].dev->bdev,
				   bbio->stripes[i].physical >> 9,
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Ilya Dryomov 已提交
681
				   sbio->bio->bi_io_vec[ix].bv_page)) {
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			/* I/O-error, this is not a good copy */
			continue;
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		}
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		if (scrub_fixup_check(sbio, ix) == 0)
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687 688
			break;
	}
689
	if (i == bbio->num_stripes)
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		goto uncorrectable;

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	if (!sdev->readonly) {
		/*
		 * bi_io_vec[ix].bv_page now contains good data, write it back
		 */
		if (scrub_fixup_io(WRITE, sdev->dev->bdev,
				   (sbio->physical + ix * PAGE_SIZE) >> 9,
				   sbio->bio->bi_io_vec[ix].bv_page)) {
			/* I/O-error, writeback failed, give up */
			goto uncorrectable;
		}
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Ilya Dryomov 已提交
702
	}
A
Arne Jansen 已提交
703

704
	kfree(bbio);
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	spin_lock(&sdev->stat_lock);
	++sdev->stat.corrected_errors;
	spin_unlock(&sdev->stat_lock);

709 710
	printk_ratelimited(KERN_ERR "btrfs: fixed up error at logical %llu\n",
			       (unsigned long long)logical);
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	return;

uncorrectable:
714
	kfree(bbio);
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	spin_lock(&sdev->stat_lock);
	++sdev->stat.uncorrectable_errors;
	spin_unlock(&sdev->stat_lock);

719 720
	printk_ratelimited(KERN_ERR "btrfs: unable to fixup (regular) error at "
				"logical %llu\n", (unsigned long long)logical);
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}

static int scrub_fixup_io(int rw, struct block_device *bdev, sector_t sector,
			 struct page *page)
{
	struct bio *bio = NULL;
	int ret;
	DECLARE_COMPLETION_ONSTACK(complete);

	bio = bio_alloc(GFP_NOFS, 1);
	bio->bi_bdev = bdev;
	bio->bi_sector = sector;
	bio_add_page(bio, page, PAGE_SIZE, 0);
	bio->bi_end_io = scrub_fixup_end_io;
	bio->bi_private = &complete;
736
	btrfsic_submit_bio(rw, bio);
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Ilya Dryomov 已提交
737

738
	/* this will also unplug the queue */
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	wait_for_completion(&complete);

	ret = !test_bit(BIO_UPTODATE, &bio->bi_flags);
	bio_put(bio);
	return ret;
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}

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

	sbio->err = err;
753
	sbio->bio = bio;
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	btrfs_queue_worker(&fs_info->scrub_workers, &sbio->work);
}

static void scrub_checksum(struct btrfs_work *work)
{
	struct scrub_bio *sbio = container_of(work, struct scrub_bio, work);
	struct scrub_dev *sdev = sbio->sdev;
	struct page *page;
	void *buffer;
	int i;
	u64 flags;
	u64 logical;
	int ret;

	if (sbio->err) {
770
		ret = 0;
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		for (i = 0; i < sbio->count; ++i)
772 773 774 775 776 777
			ret |= scrub_recheck_error(sbio, i);
		if (!ret) {
			spin_lock(&sdev->stat_lock);
			++sdev->stat.unverified_errors;
			spin_unlock(&sdev->stat_lock);
		}
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		sbio->bio->bi_flags &= ~(BIO_POOL_MASK - 1);
		sbio->bio->bi_flags |= 1 << BIO_UPTODATE;
		sbio->bio->bi_phys_segments = 0;
		sbio->bio->bi_idx = 0;

		for (i = 0; i < sbio->count; i++) {
			struct bio_vec *bi;
			bi = &sbio->bio->bi_io_vec[i];
			bi->bv_offset = 0;
			bi->bv_len = PAGE_SIZE;
		}
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		goto out;
	}
	for (i = 0; i < sbio->count; ++i) {
		page = sbio->bio->bi_io_vec[i].bv_page;
		buffer = kmap_atomic(page, KM_USER0);
		flags = sbio->spag[i].flags;
		logical = sbio->logical + i * PAGE_SIZE;
		ret = 0;
		if (flags & BTRFS_EXTENT_FLAG_DATA) {
			ret = scrub_checksum_data(sdev, sbio->spag + i, buffer);
		} else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
			ret = scrub_checksum_tree_block(sdev, sbio->spag + i,
							logical, buffer);
		} else if (flags & BTRFS_EXTENT_FLAG_SUPER) {
			BUG_ON(i);
			(void)scrub_checksum_super(sbio, buffer);
		} else {
			WARN_ON(1);
		}
		kunmap_atomic(buffer, KM_USER0);
810 811 812 813 814 815 816 817
		if (ret) {
			ret = scrub_recheck_error(sbio, i);
			if (!ret) {
				spin_lock(&sdev->stat_lock);
				++sdev->stat.unverified_errors;
				spin_unlock(&sdev->stat_lock);
			}
		}
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	}

out:
821 822
	scrub_free_bio(sbio->bio);
	sbio->bio = NULL;
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	spin_lock(&sdev->list_lock);
	sbio->next_free = sdev->first_free;
	sdev->first_free = sbio->index;
	spin_unlock(&sdev->list_lock);
	atomic_dec(&sdev->in_flight);
	wake_up(&sdev->list_wait);
}

static int scrub_checksum_data(struct scrub_dev *sdev,
			       struct scrub_page *spag, void *buffer)
{
	u8 csum[BTRFS_CSUM_SIZE];
	u32 crc = ~(u32)0;
	int fail = 0;
	struct btrfs_root *root = sdev->dev->dev_root;

	if (!spag->have_csum)
		return 0;

	crc = btrfs_csum_data(root, buffer, crc, PAGE_SIZE);
	btrfs_csum_final(crc, csum);
	if (memcmp(csum, spag->csum, sdev->csum_size))
		fail = 1;

	spin_lock(&sdev->stat_lock);
	++sdev->stat.data_extents_scrubbed;
	sdev->stat.data_bytes_scrubbed += PAGE_SIZE;
	if (fail)
		++sdev->stat.csum_errors;
	spin_unlock(&sdev->stat_lock);

	return fail;
}

static int scrub_checksum_tree_block(struct scrub_dev *sdev,
				     struct scrub_page *spag, u64 logical,
				     void *buffer)
{
	struct btrfs_header *h;
	struct btrfs_root *root = sdev->dev->dev_root;
	struct btrfs_fs_info *fs_info = root->fs_info;
	u8 csum[BTRFS_CSUM_SIZE];
	u32 crc = ~(u32)0;
	int fail = 0;
	int crc_fail = 0;

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

	if (logical != le64_to_cpu(h->bytenr))
		++fail;

	if (spag->generation != le64_to_cpu(h->generation))
		++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;

	crc = btrfs_csum_data(root, buffer + BTRFS_CSUM_SIZE, crc,
			      PAGE_SIZE - BTRFS_CSUM_SIZE);
	btrfs_csum_final(crc, csum);
	if (memcmp(csum, h->csum, sdev->csum_size))
		++crc_fail;

	spin_lock(&sdev->stat_lock);
	++sdev->stat.tree_extents_scrubbed;
	sdev->stat.tree_bytes_scrubbed += PAGE_SIZE;
	if (crc_fail)
		++sdev->stat.csum_errors;
	if (fail)
		++sdev->stat.verify_errors;
	spin_unlock(&sdev->stat_lock);

	return fail || crc_fail;
}

static int scrub_checksum_super(struct scrub_bio *sbio, void *buffer)
{
	struct btrfs_super_block *s;
	u64 logical;
	struct scrub_dev *sdev = sbio->sdev;
	struct btrfs_root *root = sdev->dev->dev_root;
	struct btrfs_fs_info *fs_info = root->fs_info;
	u8 csum[BTRFS_CSUM_SIZE];
	u32 crc = ~(u32)0;
	int fail = 0;

	s = (struct btrfs_super_block *)buffer;
	logical = sbio->logical;

	if (logical != le64_to_cpu(s->bytenr))
		++fail;

	if (sbio->spag[0].generation != le64_to_cpu(s->generation))
		++fail;

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

	crc = btrfs_csum_data(root, buffer + BTRFS_CSUM_SIZE, crc,
			      PAGE_SIZE - BTRFS_CSUM_SIZE);
	btrfs_csum_final(crc, csum);
	if (memcmp(csum, s->csum, sbio->sdev->csum_size))
		++fail;

	if (fail) {
		/*
		 * 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(&sdev->stat_lock);
		++sdev->stat.super_errors;
		spin_unlock(&sdev->stat_lock);
	}

	return fail;
}

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Stefan Behrens 已提交
950
static void scrub_submit(struct scrub_dev *sdev)
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951 952 953 954
{
	struct scrub_bio *sbio;

	if (sdev->curr == -1)
S
Stefan Behrens 已提交
955
		return;
A
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956 957 958 959 960 961

	sbio = sdev->bios[sdev->curr];
	sbio->err = 0;
	sdev->curr = -1;
	atomic_inc(&sdev->in_flight);

962
	btrfsic_submit_bio(READ, sbio->bio);
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963 964 965
}

static int scrub_page(struct scrub_dev *sdev, u64 logical, u64 len,
966
		      u64 physical, u64 flags, u64 gen, int mirror_num,
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Arne Jansen 已提交
967 968 969
		      u8 *csum, int force)
{
	struct scrub_bio *sbio;
970 971
	struct page *page;
	int ret;
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again:
	/*
	 * grab a fresh bio or wait for one to become available
	 */
	while (sdev->curr == -1) {
		spin_lock(&sdev->list_lock);
		sdev->curr = sdev->first_free;
		if (sdev->curr != -1) {
			sdev->first_free = sdev->bios[sdev->curr]->next_free;
			sdev->bios[sdev->curr]->next_free = -1;
			sdev->bios[sdev->curr]->count = 0;
			spin_unlock(&sdev->list_lock);
		} else {
			spin_unlock(&sdev->list_lock);
			wait_event(sdev->list_wait, sdev->first_free != -1);
		}
	}
	sbio = sdev->bios[sdev->curr];
	if (sbio->count == 0) {
992 993
		struct bio *bio;

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994 995
		sbio->physical = physical;
		sbio->logical = logical;
996 997 998 999 1000 1001 1002 1003 1004 1005
		bio = bio_alloc(GFP_NOFS, SCRUB_PAGES_PER_BIO);
		if (!bio)
			return -ENOMEM;

		bio->bi_private = sbio;
		bio->bi_end_io = scrub_bio_end_io;
		bio->bi_bdev = sdev->dev->bdev;
		bio->bi_sector = sbio->physical >> 9;
		sbio->err = 0;
		sbio->bio = bio;
1006 1007
	} else if (sbio->physical + sbio->count * PAGE_SIZE != physical ||
		   sbio->logical + sbio->count * PAGE_SIZE != logical) {
S
Stefan Behrens 已提交
1008
		scrub_submit(sdev);
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1009 1010 1011 1012 1013 1014
		goto again;
	}
	sbio->spag[sbio->count].flags = flags;
	sbio->spag[sbio->count].generation = gen;
	sbio->spag[sbio->count].have_csum = 0;
	sbio->spag[sbio->count].mirror_num = mirror_num;
1015 1016 1017 1018 1019 1020 1021 1022

	page = alloc_page(GFP_NOFS);
	if (!page)
		return -ENOMEM;

	ret = bio_add_page(sbio->bio, page, PAGE_SIZE, 0);
	if (!ret) {
		__free_page(page);
S
Stefan Behrens 已提交
1023
		scrub_submit(sdev);
1024 1025 1026
		goto again;
	}

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1027 1028 1029 1030 1031
	if (csum) {
		sbio->spag[sbio->count].have_csum = 1;
		memcpy(sbio->spag[sbio->count].csum, csum, sdev->csum_size);
	}
	++sbio->count;
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Stefan Behrens 已提交
1032 1033
	if (sbio->count == SCRUB_PAGES_PER_BIO || force)
		scrub_submit(sdev);
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	return 0;
}

static int scrub_find_csum(struct scrub_dev *sdev, u64 logical, u64 len,
			   u8 *csum)
{
	struct btrfs_ordered_sum *sum = NULL;
	int ret = 0;
	unsigned long i;
	unsigned long num_sectors;
	u32 sectorsize = sdev->dev->dev_root->sectorsize;

	while (!list_empty(&sdev->csum_list)) {
		sum = list_first_entry(&sdev->csum_list,
				       struct btrfs_ordered_sum, list);
		if (sum->bytenr > logical)
			return 0;
		if (sum->bytenr + sum->len > logical)
			break;

		++sdev->stat.csum_discards;
		list_del(&sum->list);
		kfree(sum);
		sum = NULL;
	}
	if (!sum)
		return 0;

	num_sectors = sum->len / sectorsize;
	for (i = 0; i < num_sectors; ++i) {
		if (sum->sums[i].bytenr == logical) {
			memcpy(csum, &sum->sums[i].sum, sdev->csum_size);
			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 */
static int scrub_extent(struct scrub_dev *sdev, u64 logical, u64 len,
1080
			u64 physical, u64 flags, u64 gen, int mirror_num)
A
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{
	int ret;
	u8 csum[BTRFS_CSUM_SIZE];

	while (len) {
		u64 l = min_t(u64, len, PAGE_SIZE);
		int have_csum = 0;

		if (flags & BTRFS_EXTENT_FLAG_DATA) {
			/* push csums to sbio */
			have_csum = scrub_find_csum(sdev, logical, l, csum);
			if (have_csum == 0)
				++sdev->stat.no_csum;
		}
		ret = scrub_page(sdev, logical, l, physical, flags, gen,
				 mirror_num, have_csum ? csum : NULL, 0);
		if (ret)
			return ret;
		len -= l;
		logical += l;
		physical += l;
	}
	return 0;
}

static noinline_for_stack int scrub_stripe(struct scrub_dev *sdev,
	struct map_lookup *map, int num, u64 base, u64 length)
{
	struct btrfs_path *path;
	struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
	struct btrfs_root *root = fs_info->extent_root;
	struct btrfs_root *csum_root = fs_info->csum_root;
	struct btrfs_extent_item *extent;
1114
	struct blk_plug plug;
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Arne Jansen 已提交
1115 1116 1117 1118 1119 1120 1121 1122 1123 1124
	u64 flags;
	int ret;
	int slot;
	int i;
	u64 nstripes;
	struct extent_buffer *l;
	struct btrfs_key key;
	u64 physical;
	u64 logical;
	u64 generation;
1125
	int mirror_num;
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1126 1127 1128 1129
	struct reada_control *reada1;
	struct reada_control *reada2;
	struct btrfs_key key_start;
	struct btrfs_key key_end;
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1130 1131 1132 1133 1134 1135 1136 1137 1138 1139

	u64 increment = map->stripe_len;
	u64 offset;

	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;
1140
		mirror_num = 1;
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1141 1142 1143 1144
	} 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;
1145
		mirror_num = num % map->sub_stripes + 1;
A
Arne Jansen 已提交
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	} else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
		increment = map->stripe_len;
1148
		mirror_num = num % map->num_stripes + 1;
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	} else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
		increment = map->stripe_len;
1151
		mirror_num = num % map->num_stripes + 1;
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	} else {
		increment = map->stripe_len;
1154
		mirror_num = 1;
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	}

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

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

	/*
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	 * 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
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	 */
	logical = base + offset;

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	wait_event(sdev->list_wait,
		   atomic_read(&sdev->in_flight) == 0);
	atomic_inc(&fs_info->scrubs_paused);
	wake_up(&fs_info->scrub_pause_wait);

	/* FIXME it might be better to start readahead at commit root */
	key_start.objectid = logical;
	key_start.type = BTRFS_EXTENT_ITEM_KEY;
	key_start.offset = (u64)0;
	key_end.objectid = base + offset + nstripes * increment;
	key_end.type = BTRFS_EXTENT_ITEM_KEY;
	key_end.offset = (u64)0;
	reada1 = btrfs_reada_add(root, &key_start, &key_end);

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

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

	mutex_lock(&fs_info->scrub_lock);
	while (atomic_read(&fs_info->scrub_pause_req)) {
		mutex_unlock(&fs_info->scrub_lock);
		wait_event(fs_info->scrub_pause_wait,
		   atomic_read(&fs_info->scrub_pause_req) == 0);
		mutex_lock(&fs_info->scrub_lock);
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Arne Jansen 已提交
1204
	}
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	atomic_dec(&fs_info->scrubs_paused);
	mutex_unlock(&fs_info->scrub_lock);
	wake_up(&fs_info->scrub_pause_wait);
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	/*
	 * collect all data csums for the stripe to avoid seeking during
	 * the scrub. This might currently (crc32) end up to be about 1MB
	 */
1213
	blk_start_plug(&plug);
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	/*
	 * now find all extents for each stripe and scrub them
	 */
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	logical = base + offset;
	physical = map->stripes[num].physical;
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	ret = 0;
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1221
	for (i = 0; i < nstripes; ++i) {
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		/*
		 * canceled?
		 */
		if (atomic_read(&fs_info->scrub_cancel_req) ||
		    atomic_read(&sdev->cancel_req)) {
			ret = -ECANCELED;
			goto out;
		}
		/*
		 * check to see if we have to pause
		 */
		if (atomic_read(&fs_info->scrub_pause_req)) {
			/* push queued extents */
			scrub_submit(sdev);
			wait_event(sdev->list_wait,
				   atomic_read(&sdev->in_flight) == 0);
			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);
		}

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

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		key.objectid = logical;
		key.type = BTRFS_EXTENT_ITEM_KEY;
		key.offset = (u64)0;

		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
		if (ret < 0)
			goto out;
1265
		if (ret > 0) {
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			ret = btrfs_previous_item(root, path, 0,
						  BTRFS_EXTENT_ITEM_KEY);
			if (ret < 0)
				goto out;
1270 1271 1272 1273 1274 1275 1276 1277 1278
			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;
			}
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		}

		while (1) {
			l = path->nodes[0];
			slot = path->slots[0];
			if (slot >= btrfs_header_nritems(l)) {
				ret = btrfs_next_leaf(root, path);
				if (ret == 0)
					continue;
				if (ret < 0)
					goto out;

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

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

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

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

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

			if (key.objectid < logical &&
			    (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK)) {
				printk(KERN_ERR
				       "btrfs scrub: tree block %llu spanning "
				       "stripes, ignored. logical=%llu\n",
				       (unsigned long long)key.objectid,
				       (unsigned long long)logical);
				goto next;
			}

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

			ret = scrub_extent(sdev, key.objectid, key.offset,
					   key.objectid - logical + physical,
					   flags, generation, mirror_num);
			if (ret)
				goto out;

next:
			path->slots[0]++;
		}
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		btrfs_release_path(path);
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		logical += increment;
		physical += map->stripe_len;
		spin_lock(&sdev->stat_lock);
		sdev->stat.last_physical = physical;
		spin_unlock(&sdev->stat_lock);
	}
	/* push queued extents */
	scrub_submit(sdev);

out:
1352
	blk_finish_plug(&plug);
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	btrfs_free_path(path);
	return ret < 0 ? ret : 0;
}

static noinline_for_stack int scrub_chunk(struct scrub_dev *sdev,
1358 1359
	u64 chunk_tree, u64 chunk_objectid, u64 chunk_offset, u64 length,
	u64 dev_offset)
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{
	struct btrfs_mapping_tree *map_tree =
		&sdev->dev->dev_root->fs_info->mapping_tree;
	struct map_lookup *map;
	struct extent_map *em;
	int i;
	int ret = -EINVAL;

	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) {
1383 1384
		if (map->stripes[i].dev == sdev->dev &&
		    map->stripes[i].physical == dev_offset) {
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			ret = scrub_stripe(sdev, map, i, chunk_offset, length);
			if (ret)
				goto out;
		}
	}
out:
	free_extent_map(em);

	return ret;
}

static noinline_for_stack
int scrub_enumerate_chunks(struct scrub_dev *sdev, u64 start, u64 end)
{
	struct btrfs_dev_extent *dev_extent = NULL;
	struct btrfs_path *path;
	struct btrfs_root *root = sdev->dev->dev_root;
	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;

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

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

	key.objectid = sdev->dev->devid;
	key.offset = 0ull;
	key.type = BTRFS_DEV_EXTENT_KEY;


	while (1) {
		ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
		if (ret < 0)
1430 1431 1432 1433 1434 1435 1436 1437 1438
			break;
		if (ret > 0) {
			if (path->slots[0] >=
			    btrfs_header_nritems(path->nodes[0])) {
				ret = btrfs_next_leaf(root, path);
				if (ret)
					break;
			}
		}
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		l = path->nodes[0];
		slot = path->slots[0];

		btrfs_item_key_to_cpu(l, &found_key, slot);

		if (found_key.objectid != sdev->dev->devid)
			break;

1448
		if (btrfs_key_type(&found_key) != BTRFS_DEV_EXTENT_KEY)
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			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;
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			btrfs_release_path(path);
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1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476
			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;
1477
			break;
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1478 1479
		}
		ret = scrub_chunk(sdev, chunk_tree, chunk_objectid,
1480
				  chunk_offset, length, found_key.offset);
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1481 1482 1483 1484 1485
		btrfs_put_block_group(cache);
		if (ret)
			break;

		key.offset = found_key.offset + length;
C
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		btrfs_release_path(path);
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	}

	btrfs_free_path(path);
1490 1491 1492 1493 1494 1495

	/*
	 * ret can still be 1 from search_slot or next_leaf,
	 * that's not an error
	 */
	return ret < 0 ? ret : 0;
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}

static noinline_for_stack int scrub_supers(struct scrub_dev *sdev)
{
	int	i;
	u64	bytenr;
	u64	gen;
	int	ret;
	struct btrfs_device *device = sdev->dev;
	struct btrfs_root *root = device->dev_root;

	gen = root->fs_info->last_trans_committed;

	for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
		bytenr = btrfs_sb_offset(i);
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Stefan Behrens 已提交
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		if (bytenr + BTRFS_SUPER_INFO_SIZE > device->total_bytes)
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			break;

		ret = scrub_page(sdev, bytenr, PAGE_SIZE, bytenr,
				 BTRFS_EXTENT_FLAG_SUPER, gen, i, NULL, 1);
		if (ret)
			return ret;
	}
	wait_event(sdev->list_wait, atomic_read(&sdev->in_flight) == 0);

	return 0;
}

/*
 * get a reference count on fs_info->scrub_workers. start worker if necessary
 */
static noinline_for_stack int scrub_workers_get(struct btrfs_root *root)
{
	struct btrfs_fs_info *fs_info = root->fs_info;
1530
	int ret = 0;
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	mutex_lock(&fs_info->scrub_lock);
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	if (fs_info->scrub_workers_refcnt == 0) {
		btrfs_init_workers(&fs_info->scrub_workers, "scrub",
			   fs_info->thread_pool_size, &fs_info->generic_worker);
		fs_info->scrub_workers.idle_thresh = 4;
1537 1538 1539
		ret = btrfs_start_workers(&fs_info->scrub_workers);
		if (ret)
			goto out;
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	}
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	++fs_info->scrub_workers_refcnt;
1542
out:
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	mutex_unlock(&fs_info->scrub_lock);

1545
	return ret;
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}

static noinline_for_stack void scrub_workers_put(struct btrfs_root *root)
{
	struct btrfs_fs_info *fs_info = root->fs_info;

	mutex_lock(&fs_info->scrub_lock);
	if (--fs_info->scrub_workers_refcnt == 0)
		btrfs_stop_workers(&fs_info->scrub_workers);
	WARN_ON(fs_info->scrub_workers_refcnt < 0);
	mutex_unlock(&fs_info->scrub_lock);
}


int btrfs_scrub_dev(struct btrfs_root *root, u64 devid, u64 start, u64 end,
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1561
		    struct btrfs_scrub_progress *progress, int readonly)
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{
	struct scrub_dev *sdev;
	struct btrfs_fs_info *fs_info = root->fs_info;
	int ret;
	struct btrfs_device *dev;

1568
	if (btrfs_fs_closing(root->fs_info))
A
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		return -EINVAL;

	/*
	 * check some assumptions
	 */
	if (root->sectorsize != PAGE_SIZE ||
	    root->sectorsize != root->leafsize ||
	    root->sectorsize != root->nodesize) {
		printk(KERN_ERR "btrfs_scrub: size assumptions fail\n");
		return -EINVAL;
	}

	ret = scrub_workers_get(root);
	if (ret)
		return ret;

	mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
	dev = btrfs_find_device(root, devid, NULL, NULL);
	if (!dev || dev->missing) {
		mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
		scrub_workers_put(root);
		return -ENODEV;
	}
	mutex_lock(&fs_info->scrub_lock);

	if (!dev->in_fs_metadata) {
		mutex_unlock(&fs_info->scrub_lock);
		mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
		scrub_workers_put(root);
		return -ENODEV;
	}

	if (dev->scrub_device) {
		mutex_unlock(&fs_info->scrub_lock);
		mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
		scrub_workers_put(root);
		return -EINPROGRESS;
	}
	sdev = scrub_setup_dev(dev);
	if (IS_ERR(sdev)) {
		mutex_unlock(&fs_info->scrub_lock);
		mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
		scrub_workers_put(root);
		return PTR_ERR(sdev);
	}
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1614
	sdev->readonly = readonly;
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1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631
	dev->scrub_device = sdev;

	atomic_inc(&fs_info->scrubs_running);
	mutex_unlock(&fs_info->scrub_lock);
	mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);

	down_read(&fs_info->scrub_super_lock);
	ret = scrub_supers(sdev);
	up_read(&fs_info->scrub_super_lock);

	if (!ret)
		ret = scrub_enumerate_chunks(sdev, start, end);

	wait_event(sdev->list_wait, atomic_read(&sdev->in_flight) == 0);
	atomic_dec(&fs_info->scrubs_running);
	wake_up(&fs_info->scrub_pause_wait);

1632 1633
	wait_event(sdev->list_wait, atomic_read(&sdev->fixup_cnt) == 0);

A
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1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731
	if (progress)
		memcpy(progress, &sdev->stat, sizeof(*progress));

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

	scrub_free_dev(sdev);
	scrub_workers_put(root);

	return ret;
}

int btrfs_scrub_pause(struct btrfs_root *root)
{
	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);

	return 0;
}

int btrfs_scrub_continue(struct btrfs_root *root)
{
	struct btrfs_fs_info *fs_info = root->fs_info;

	atomic_dec(&fs_info->scrub_pause_req);
	wake_up(&fs_info->scrub_pause_wait);
	return 0;
}

int btrfs_scrub_pause_super(struct btrfs_root *root)
{
	down_write(&root->fs_info->scrub_super_lock);
	return 0;
}

int btrfs_scrub_continue_super(struct btrfs_root *root)
{
	up_write(&root->fs_info->scrub_super_lock);
	return 0;
}

int btrfs_scrub_cancel(struct btrfs_root *root)
{
	struct btrfs_fs_info *fs_info = root->fs_info;

	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;
}

int btrfs_scrub_cancel_dev(struct btrfs_root *root, struct btrfs_device *dev)
{
	struct btrfs_fs_info *fs_info = root->fs_info;
	struct scrub_dev *sdev;

	mutex_lock(&fs_info->scrub_lock);
	sdev = dev->scrub_device;
	if (!sdev) {
		mutex_unlock(&fs_info->scrub_lock);
		return -ENOTCONN;
	}
	atomic_inc(&sdev->cancel_req);
	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
1732

A
Arne Jansen 已提交
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int btrfs_scrub_cancel_devid(struct btrfs_root *root, u64 devid)
{
	struct btrfs_fs_info *fs_info = root->fs_info;
	struct btrfs_device *dev;
	int ret;

	/*
	 * we have to hold the device_list_mutex here so the device
	 * does not go away in cancel_dev. FIXME: find a better solution
	 */
	mutex_lock(&fs_info->fs_devices->device_list_mutex);
	dev = btrfs_find_device(root, devid, NULL, NULL);
	if (!dev) {
		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
		return -ENODEV;
	}
	ret = btrfs_scrub_cancel_dev(root, dev);
	mutex_unlock(&fs_info->fs_devices->device_list_mutex);

	return ret;
}

int btrfs_scrub_progress(struct btrfs_root *root, u64 devid,
			 struct btrfs_scrub_progress *progress)
{
	struct btrfs_device *dev;
	struct scrub_dev *sdev = NULL;

	mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
	dev = btrfs_find_device(root, devid, NULL, NULL);
	if (dev)
		sdev = dev->scrub_device;
	if (sdev)
		memcpy(progress, &sdev->stat, sizeof(*progress));
	mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);

	return dev ? (sdev ? 0 : -ENOTCONN) : -ENODEV;
}