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btrfs: unify buffered and direct I/O read repair
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Currently, direct I/O has its own versions of bio_readpage_error() and
btrfs_check_repairable() (dio_read_error() and
btrfs_check_dio_repairable(), respectively). The main difference is that
the direct I/O version doesn't do read validation. The rework of direct
I/O repair makes it possible to do validation, so we can get rid of
btrfs_check_dio_repairable() and combine bio_readpage_error() and
dio_read_error() into a new helper, btrfs_submit_read_repair().

Reviewed-by: Josef Bacik <[email protected]>
Signed-off-by: Omar Sandoval <[email protected]>
Signed-off-by: David Sterba <[email protected]>
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@osandov @kdave
osandov authored and kdave committed May 25, 2020
1 parent 5c047a6 commit 77d5d68
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Showing 3 changed files with 86 additions and 170 deletions.
136 changes: 64 additions & 72 deletions fs/btrfs/extent_io.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2601,46 +2601,10 @@ static bool btrfs_check_repairable(struct inode *inode, bool needs_validation,
return true;
}


struct bio *btrfs_create_repair_bio(struct inode *inode, struct bio *failed_bio,
struct io_failure_record *failrec,
struct page *page, int pg_offset, int icsum,
bio_end_io_t *endio_func, void *data)
{
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
struct bio *bio;
struct btrfs_io_bio *btrfs_failed_bio;
struct btrfs_io_bio *btrfs_bio;

bio = btrfs_io_bio_alloc(1);
bio->bi_end_io = endio_func;
bio->bi_iter.bi_sector = failrec->logical >> 9;
bio->bi_iter.bi_size = 0;
bio->bi_private = data;

btrfs_failed_bio = btrfs_io_bio(failed_bio);
if (btrfs_failed_bio->csum) {
u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);

btrfs_bio = btrfs_io_bio(bio);
btrfs_bio->csum = btrfs_bio->csum_inline;
icsum *= csum_size;
memcpy(btrfs_bio->csum, btrfs_failed_bio->csum + icsum,
csum_size);
}

bio_add_page(bio, page, failrec->len, pg_offset);
btrfs_io_bio(bio)->logical = failrec->start;
btrfs_io_bio(bio)->iter = bio->bi_iter;

return bio;
}

static bool btrfs_io_needs_validation(struct inode *inode, struct bio *bio)
{
struct bio_vec *bvec;
u64 len = 0;
int i;
const u32 blocksize = inode->i_sb->s_blocksize;

/*
* If bi_status is BLK_STS_OK, then this was a checksum error, not an
Expand All @@ -2653,72 +2617,99 @@ static bool btrfs_io_needs_validation(struct inode *inode, struct bio *bio)
/*
* We need to validate each sector individually if the failed I/O was
* for multiple sectors.
*
* There are a few possible bios that can end up here:
* 1. A buffered read bio, which is not cloned.
* 2. A direct I/O read bio, which is cloned.
* 3. A (buffered or direct) repair bio, which is not cloned.
*
* For cloned bios (case 2), we can get the size from
* btrfs_io_bio->iter; for non-cloned bios (cases 1 and 3), we can get
* it from the bvecs.
*/
bio_for_each_bvec_all(bvec, bio, i) {
len += bvec->bv_len;
if (len > inode->i_sb->s_blocksize)
if (bio_flagged(bio, BIO_CLONED)) {
if (btrfs_io_bio(bio)->iter.bi_size > blocksize)
return true;
} else {
struct bio_vec *bvec;
int i;

bio_for_each_bvec_all(bvec, bio, i) {
len += bvec->bv_len;
if (len > blocksize)
return true;
}
}
return false;
}

/*
* This is a generic handler for readpage errors. If other copies exist, read
* those and write back good data to the failed position. Does not investigate
* in remapping the failed extent elsewhere, hoping the device will be smart
* enough to do this as needed
*/
static int bio_readpage_error(struct bio *failed_bio, u64 phy_offset,
struct page *page, u64 start, u64 end,
int failed_mirror)
blk_status_t btrfs_submit_read_repair(struct inode *inode,
struct bio *failed_bio, u64 phy_offset,
struct page *page, unsigned int pgoff,
u64 start, u64 end, int failed_mirror,
submit_bio_hook_t *submit_bio_hook)
{
struct io_failure_record *failrec;
struct inode *inode = page->mapping->host;
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
struct btrfs_io_bio *failed_io_bio = btrfs_io_bio(failed_bio);
const int icsum = phy_offset >> inode->i_sb->s_blocksize_bits;
bool need_validation;
struct bio *bio;
int read_mode = 0;
struct bio *repair_bio;
struct btrfs_io_bio *repair_io_bio;
blk_status_t status;
int ret;

btrfs_debug(fs_info,
"repair read error: read error at %llu", start);

BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);

ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
if (ret)
return ret;
return errno_to_blk_status(ret);

need_validation = btrfs_io_needs_validation(inode, failed_bio);

if (!btrfs_check_repairable(inode, need_validation, failrec,
failed_mirror)) {
free_io_failure(failure_tree, tree, failrec);
return -EIO;
return BLK_STS_IOERR;
}

repair_bio = btrfs_io_bio_alloc(1);
repair_io_bio = btrfs_io_bio(repair_bio);
repair_bio->bi_opf = REQ_OP_READ;
if (need_validation)
read_mode |= REQ_FAILFAST_DEV;
repair_bio->bi_opf |= REQ_FAILFAST_DEV;
repair_bio->bi_end_io = failed_bio->bi_end_io;
repair_bio->bi_iter.bi_sector = failrec->logical >> 9;
repair_bio->bi_private = failed_bio->bi_private;

phy_offset >>= inode->i_sb->s_blocksize_bits;
bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page,
start - page_offset(page),
(int)phy_offset, failed_bio->bi_end_io,
NULL);
bio->bi_opf = REQ_OP_READ | read_mode;
if (failed_io_bio->csum) {
const u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);

repair_io_bio->csum = repair_io_bio->csum_inline;
memcpy(repair_io_bio->csum,
failed_io_bio->csum + csum_size * icsum, csum_size);
}

bio_add_page(repair_bio, page, failrec->len, pgoff);
repair_io_bio->logical = failrec->start;
repair_io_bio->iter = repair_bio->bi_iter;

btrfs_debug(btrfs_sb(inode->i_sb),
"Repair Read Error: submitting new read[%#x] to this_mirror=%d, in_validation=%d",
read_mode, failrec->this_mirror, failrec->in_validation);
"repair read error: submitting new read to mirror %d, in_validation=%d",
failrec->this_mirror, failrec->in_validation);

status = tree->ops->submit_bio_hook(tree->private_data, bio, failrec->this_mirror,
failrec->bio_flags);
status = submit_bio_hook(inode, repair_bio, failrec->this_mirror,
failrec->bio_flags);
if (status) {
free_io_failure(failure_tree, tree, failrec);
bio_put(bio);
ret = blk_status_to_errno(status);
bio_put(repair_bio);
}

return ret;
return status;
}

/* lots and lots of room for performance fixes in the end_bio funcs */
Expand Down Expand Up @@ -2890,9 +2881,10 @@ static void end_bio_extent_readpage(struct bio *bio)
* If it can't handle the error it will return -EIO and
* we remain responsible for that page.
*/
ret = bio_readpage_error(bio, offset, page, start, end,
mirror);
if (ret == 0) {
if (!btrfs_submit_read_repair(inode, bio, offset, page,
start - page_offset(page),
start, end, mirror,
tree->ops->submit_bio_hook)) {
uptodate = !bio->bi_status;
offset += len;
continue;
Expand Down
17 changes: 11 additions & 6 deletions fs/btrfs/extent_io.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -66,6 +66,10 @@ struct btrfs_io_bio;
struct io_failure_record;
struct extent_io_tree;

typedef blk_status_t (submit_bio_hook_t)(struct inode *inode, struct bio *bio,
int mirror_num,
unsigned long bio_flags);

typedef blk_status_t (extent_submit_bio_start_t)(void *private_data,
struct bio *bio, u64 bio_offset);

Expand All @@ -74,8 +78,7 @@ struct extent_io_ops {
* The following callbacks must be always defined, the function
* pointer will be called unconditionally.
*/
blk_status_t (*submit_bio_hook)(struct inode *inode, struct bio *bio,
int mirror_num, unsigned long bio_flags);
submit_bio_hook_t *submit_bio_hook;
int (*readpage_end_io_hook)(struct btrfs_io_bio *io_bio, u64 phy_offset,
struct page *page, u64 start, u64 end,
int mirror);
Expand Down Expand Up @@ -312,10 +315,12 @@ struct io_failure_record {
};


struct bio *btrfs_create_repair_bio(struct inode *inode, struct bio *failed_bio,
struct io_failure_record *failrec,
struct page *page, int pg_offset, int icsum,
bio_end_io_t *endio_func, void *data);
blk_status_t btrfs_submit_read_repair(struct inode *inode,
struct bio *failed_bio, u64 phy_offset,
struct page *page, unsigned int pgoff,
u64 start, u64 end, int failed_mirror,
submit_bio_hook_t *submit_bio_hook);

#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
bool find_lock_delalloc_range(struct inode *inode,
struct page *locked_page, u64 *start,
Expand Down
103 changes: 11 additions & 92 deletions fs/btrfs/inode.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -7379,10 +7379,11 @@ static void btrfs_dio_private_put(struct btrfs_dio_private *dip)
kfree(dip);
}

static inline blk_status_t submit_dio_repair_bio(struct inode *inode,
struct bio *bio,
int mirror_num)
static blk_status_t submit_dio_repair_bio(struct inode *inode, struct bio *bio,
int mirror_num,
unsigned long bio_flags)
{
struct btrfs_dio_private *dip = bio->bi_private;
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
blk_status_t ret;

Expand All @@ -7392,96 +7393,11 @@ static inline blk_status_t submit_dio_repair_bio(struct inode *inode,
if (ret)
return ret;

refcount_inc(&dip->refs);
ret = btrfs_map_bio(fs_info, bio, mirror_num);

return ret;
}

static int btrfs_check_dio_repairable(struct inode *inode,
struct bio *failed_bio,
struct io_failure_record *failrec,
int failed_mirror)
{
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
int num_copies;

num_copies = btrfs_num_copies(fs_info, failrec->logical, failrec->len);
if (num_copies == 1) {
/*
* we only have a single copy of the data, so don't bother with
* all the retry and error correction code that follows. no
* matter what the error is, it is very likely to persist.
*/
btrfs_debug(fs_info,
"Check DIO Repairable: cannot repair, num_copies=%d, next_mirror %d, failed_mirror %d",
num_copies, failrec->this_mirror, failed_mirror);
return 0;
}

failrec->failed_mirror = failed_mirror;
failrec->this_mirror++;
if (failrec->this_mirror == failed_mirror)
failrec->this_mirror++;

if (failrec->this_mirror > num_copies) {
btrfs_debug(fs_info,
"Check DIO Repairable: (fail) num_copies=%d, next_mirror %d, failed_mirror %d",
num_copies, failrec->this_mirror, failed_mirror);
return 0;
}

return 1;
}

static blk_status_t dio_read_error(struct inode *inode, struct bio *failed_bio,
struct page *page, unsigned int pgoff,
u64 start, u64 end, int failed_mirror)
{
struct btrfs_dio_private *dip = failed_bio->bi_private;
struct io_failure_record *failrec;
struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
struct bio *bio;
int isector;
unsigned int read_mode = 0;
int ret;
blk_status_t status;

BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);

ret = btrfs_get_io_failure_record(inode, start, end, &failrec);
if (ret)
return errno_to_blk_status(ret);

ret = btrfs_check_dio_repairable(inode, failed_bio, failrec,
failed_mirror);
if (!ret) {
free_io_failure(failure_tree, io_tree, failrec);
return BLK_STS_IOERR;
}

if (btrfs_io_bio(failed_bio)->iter.bi_size > inode->i_sb->s_blocksize)
read_mode |= REQ_FAILFAST_DEV;

isector = start - btrfs_io_bio(failed_bio)->logical;
isector >>= inode->i_sb->s_blocksize_bits;
bio = btrfs_create_repair_bio(inode, failed_bio, failrec, page, pgoff,
isector, failed_bio->bi_end_io, dip);
bio->bi_opf = REQ_OP_READ | read_mode;

btrfs_debug(BTRFS_I(inode)->root->fs_info,
"repair DIO read error: submitting new dio read[%#x] to this_mirror=%d, in_validation=%d",
read_mode, failrec->this_mirror, failrec->in_validation);

refcount_inc(&dip->refs);
status = submit_dio_repair_bio(inode, bio, failrec->this_mirror);
if (status) {
free_io_failure(failure_tree, io_tree, failrec);
bio_put(bio);
refcount_dec(&dip->refs);
}

return status;
return ret;
}

static blk_status_t btrfs_check_read_dio_bio(struct inode *inode,
Expand Down Expand Up @@ -7517,11 +7433,14 @@ static blk_status_t btrfs_check_read_dio_bio(struct inode *inode,
} else {
blk_status_t status;

status = dio_read_error(inode, &io_bio->bio,
status = btrfs_submit_read_repair(inode,
&io_bio->bio,
start - io_bio->logical,
bvec.bv_page, pgoff,
start,
start + sectorsize - 1,
io_bio->mirror_num);
io_bio->mirror_num,
submit_dio_repair_bio);
if (status)
err = status;
}
Expand Down

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