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linux/fs/btrfs/scrub.c

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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>
#include "ctree.h"
#include "volumes.h"
#include "disk-io.h"
#include "ordered-data.h"
/*
* 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:
* - To enhance the performance, better read-ahead strategies for the
* extent-tree can be employed.
* - In case an unrepairable extent is encountered, track which files are
* affected and report them
* - In case of a read error on files with nodatasum, map the file and read
* the extent to trigger a writeback of the good copy
* - track and record media errors, throw out bad devices
* - add a mode to also read unallocated space
* - make the prefetch cancellable
*/
struct scrub_bio;
struct scrub_page;
struct scrub_dev;
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);
#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;
u64 mirror_num;
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;
spinlock_t list_lock;
wait_queue_head_t list_wait;
u16 csum_size;
struct list_head csum_list;
atomic_t cancel_req;
int readonly;
/*
* statistics
*/
struct btrfs_scrub_progress stat;
spinlock_t stat_lock;
};
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);
}
}
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);
}
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;
scrub_free_bio(sbio->bio);
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;
else
sdev->bios[i]->next_free = -1;
}
sdev->first_free = 0;
sdev->curr = -1;
atomic_set(&sdev->in_flight, 0);
atomic_set(&sdev->cancel_req, 0);
sdev->csum_size = btrfs_super_csum_size(&fs_info->super_copy);
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);
}
/*
* 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
*/
static void scrub_recheck_error(struct scrub_bio *sbio, int ix)
{
if (sbio->err) {
if (scrub_fixup_io(READ, sbio->sdev->dev->bdev,
(sbio->physical + ix * PAGE_SIZE) >> 9,
sbio->bio->bi_io_vec[ix].bv_page) == 0) {
if (scrub_fixup_check(sbio, ix) == 0)
return;
}
}
scrub_fixup(sbio, ix);
}
static int scrub_fixup_check(struct scrub_bio *sbio, int ix)
{
int ret = 1;
struct page *page;
void *buffer;
u64 flags = sbio->spag[ix].flags;
page = sbio->bio->bi_io_vec[ix].bv_page;
buffer = kmap_atomic(page, KM_USER0);
if (flags & BTRFS_EXTENT_FLAG_DATA) {
ret = scrub_checksum_data(sbio->sdev,
sbio->spag + ix, buffer);
} else if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
ret = scrub_checksum_tree_block(sbio->sdev,
sbio->spag + ix,
sbio->logical + ix * PAGE_SIZE,
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);
}
static void scrub_fixup(struct scrub_bio *sbio, int ix)
{
struct scrub_dev *sdev = sbio->sdev;
struct btrfs_fs_info *fs_info = sdev->dev->dev_root->fs_info;
struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
struct btrfs_multi_bio *multi = NULL;
u64 logical = sbio->logical + ix * PAGE_SIZE;
u64 length;
int i;
int ret;
DECLARE_COMPLETION_ONSTACK(complete);
if ((sbio->spag[ix].flags & BTRFS_EXTENT_FLAG_DATA) &&
(sbio->spag[ix].have_csum == 0)) {
/*
* nodatasum, don't try to fix anything
* FIXME: we can do better, open the inode and trigger a
* writeback
*/
goto uncorrectable;
}
length = PAGE_SIZE;
ret = btrfs_map_block(map_tree, REQ_WRITE, logical, &length,
&multi, 0);
if (ret || !multi || length < PAGE_SIZE) {
printk(KERN_ERR
"scrub_fixup: btrfs_map_block failed us for %llu\n",
(unsigned long long)logical);
WARN_ON(1);
return;
}
if (multi->num_stripes == 1)
/* there aren't any replicas */
goto uncorrectable;
/*
* first find a good copy
*/
for (i = 0; i < multi->num_stripes; ++i) {
if (i == sbio->spag[ix].mirror_num)
continue;
if (scrub_fixup_io(READ, multi->stripes[i].dev->bdev,
multi->stripes[i].physical >> 9,
sbio->bio->bi_io_vec[ix].bv_page)) {
/* I/O-error, this is not a good copy */
continue;
}
if (scrub_fixup_check(sbio, ix) == 0)
break;
}
if (i == multi->num_stripes)
goto uncorrectable;
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;
}
}
kfree(multi);
spin_lock(&sdev->stat_lock);
++sdev->stat.corrected_errors;
spin_unlock(&sdev->stat_lock);
if (printk_ratelimit())
printk(KERN_ERR "btrfs: fixed up at %llu\n",
(unsigned long long)logical);
return;
uncorrectable:
kfree(multi);
spin_lock(&sdev->stat_lock);
++sdev->stat.uncorrectable_errors;
spin_unlock(&sdev->stat_lock);
if (printk_ratelimit())
printk(KERN_ERR "btrfs: unable to fixup at %llu\n",
(unsigned long long)logical);
}
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;
submit_bio(rw, bio);
/* this will also unplug the queue */
wait_for_completion(&complete);
ret = !test_bit(BIO_UPTODATE, &bio->bi_flags);
bio_put(bio);
return ret;
}
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;
sbio->bio = bio;
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) {
for (i = 0; i < sbio->count; ++i)
scrub_recheck_error(sbio, i);
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;
}
spin_lock(&sdev->stat_lock);
++sdev->stat.read_errors;
spin_unlock(&sdev->stat_lock);
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);
if (ret)
scrub_recheck_error(sbio, i);
}
out:
scrub_free_bio(sbio->bio);
sbio->bio = NULL;
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;
}
static int scrub_submit(struct scrub_dev *sdev)
{
struct scrub_bio *sbio;
struct bio *bio;
int i;
if (sdev->curr == -1)
return 0;
sbio = sdev->bios[sdev->curr];
bio = bio_alloc(GFP_NOFS, sbio->count);
if (!bio)
goto nomem;
bio->bi_private = sbio;
bio->bi_end_io = scrub_bio_end_io;
bio->bi_bdev = sdev->dev->bdev;
bio->bi_sector = sbio->physical >> 9;
for (i = 0; i < sbio->count; ++i) {
struct page *page;
int ret;
page = alloc_page(GFP_NOFS);
if (!page)
goto nomem;
ret = bio_add_page(bio, page, PAGE_SIZE, 0);
if (!ret) {
__free_page(page);
goto nomem;
}
}
sbio->err = 0;
sdev->curr = -1;
atomic_inc(&sdev->in_flight);
submit_bio(READ, bio);
return 0;
nomem:
scrub_free_bio(bio);
return -ENOMEM;
}
static int scrub_page(struct scrub_dev *sdev, u64 logical, u64 len,
u64 physical, u64 flags, u64 gen, u64 mirror_num,
u8 *csum, int force)
{
struct scrub_bio *sbio;
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) {
sbio->physical = physical;
sbio->logical = logical;
} else if (sbio->physical + sbio->count * PAGE_SIZE != physical ||
sbio->logical + sbio->count * PAGE_SIZE != logical) {
int ret;
ret = scrub_submit(sdev);
if (ret)
return ret;
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;
if (csum) {
sbio->spag[sbio->count].have_csum = 1;
memcpy(sbio->spag[sbio->count].csum, csum, sdev->csum_size);
}
++sbio->count;
if (sbio->count == SCRUB_PAGES_PER_BIO || force) {
int ret;
ret = scrub_submit(sdev);
if (ret)
return ret;
}
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,
u64 physical, u64 flags, u64 gen, u64 mirror_num)
{
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;
struct blk_plug plug;
u64 flags;
int ret;
int slot;
int i;
u64 nstripes;
int start_stripe;
struct extent_buffer *l;
struct btrfs_key key;
u64 physical;
u64 logical;
u64 generation;
u64 mirror_num;
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;
mirror_num = 0;
} 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;
mirror_num = num % map->sub_stripes;
} else if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
increment = map->stripe_len;
mirror_num = num % map->num_stripes;
} else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
increment = map->stripe_len;
mirror_num = num % map->num_stripes;
} else {
increment = map->stripe_len;
mirror_num = 0;
}
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
path->reada = 2;
path->search_commit_root = 1;
path->skip_locking = 1;
/*
* find all extents for each stripe and just read them to get
* them into the page cache
* FIXME: we can do better. build a more intelligent prefetching
*/
logical = base + offset;
physical = map->stripes[num].physical;
ret = 0;
for (i = 0; i < nstripes; ++i) {
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_noplug;
/*
* we might miss half an extent here, but that doesn't matter,
* as it's only the prefetch
*/
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_noplug;
break;
}
btrfs_item_key_to_cpu(l, &key, slot);
if (key.objectid >= logical + map->stripe_len)
break;
path->slots[0]++;
}
btrfs_release_path(path);
logical += increment;
physical += map->stripe_len;
cond_resched();
}
/*
* collect all data csums for the stripe to avoid seeking during
* the scrub. This might currently (crc32) end up to be about 1MB
*/
start_stripe = 0;
blk_start_plug(&plug);
again:
logical = base + offset + start_stripe * increment;
for (i = start_stripe; i < nstripes; ++i) {
ret = btrfs_lookup_csums_range(csum_root, logical,
logical + map->stripe_len - 1,
&sdev->csum_list, 1);
if (ret)
goto out;
logical += increment;
cond_resched();
}
/*
* now find all extents for each stripe and scrub them
*/
logical = base + offset + start_stripe * increment;
physical = map->stripes[num].physical + start_stripe * map->stripe_len;
ret = 0;
for (i = start_stripe; i < nstripes; ++i) {
/*
* 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);
scrub_free_csums(sdev);
start_stripe = i;
goto again;
}
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;
if (ret > 0) {
ret = btrfs_previous_item(root, path, 0,
BTRFS_EXTENT_ITEM_KEY);
if (ret < 0)
goto out;
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;
}
}
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]++;
}
btrfs_release_path(path);
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:
blk_finish_plug(&plug);
out_noplug:
btrfs_free_path(path);
return ret < 0 ? ret : 0;
}
static noinline_for_stack int scrub_chunk(struct scrub_dev *sdev,
u64 chunk_tree, u64 chunk_objectid, u64 chunk_offset, u64 length)
{
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) {
if (map->stripes[i].dev == sdev->dev) {
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)
break;
if (ret > 0) {
if (path->slots[0] >=
btrfs_header_nritems(path->nodes[0])) {
ret = btrfs_next_leaf(root, path);
if (ret)
break;
}
}
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;
if (btrfs_key_type(&found_key) != BTRFS_DEV_EXTENT_KEY)
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;
btrfs_release_path(path);
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;
break;
}
ret = scrub_chunk(sdev, chunk_tree, chunk_objectid,
chunk_offset, length);
btrfs_put_block_group(cache);
if (ret)
break;
key.offset = found_key.offset + length;
btrfs_release_path(path);
}
btrfs_free_path(path);
/*
* ret can still be 1 from search_slot or next_leaf,
* that's not an error
*/
return ret < 0 ? ret : 0;
}
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);
if (bytenr + BTRFS_SUPER_INFO_SIZE >= device->total_bytes)
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;
mutex_lock(&fs_info->scrub_lock);
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;
btrfs_start_workers(&fs_info->scrub_workers, 1);
}
++fs_info->scrub_workers_refcnt;
mutex_unlock(&fs_info->scrub_lock);
return 0;
}
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,
struct btrfs_scrub_progress *progress, int readonly)
{
struct scrub_dev *sdev;
struct btrfs_fs_info *fs_info = root->fs_info;
int ret;
struct btrfs_device *dev;
if (btrfs_fs_closing(root->fs_info))
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);
}
sdev->readonly = readonly;
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);
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;
}
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;
}
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