Re: [PATCH 04/17] btrfs: handle checksum validation and repair at the storage layer

[Qu Wenruo <quwenruo.btrfs@gmx.com>]

On 2022/9/1 15:42, Christoph Hellwig wrote:
> Currently btrfs handles checksum validation and repair in the end I/O
> handler for the btrfs_bio.  This leads to a lot of duplicate code
> plus issues with variying semantics or bugs, e.g.
>
>   - the until recently completetly broken repair for compressed extents
>   - the fact that encoded reads validate the checksums but do not kick
>     of read repair
>   - the inconsistent checking of the BTRFS_FS_STATE_NO_CSUMS flag
>
> This commit revamps the checksum validation and repair code to instead
> work below the btrfs_submit_bio interfaces.

I'm 100% into the idea of pre-loading the csum at btrfs_submit_bio() time.

That's definitely the way we should go.

> For this to work we need
> to make sure an inode is available, so that is added as a parameter
> to btrfs_bio_alloc.  With that btrfs_submit_bio can preload
> btrfs_bio.csum from the csum tree without help from the upper layers,
> and the low-level I/O completion can iterate over the bio and verify
> the checksums.

But for the verification part, I still don't like the idea of putting
the verification code at endio context at all.

This is especially true when data and metadata are still doing different
checksum verfication at different timing.

Can we just let the endio function to do the IO, and let the reader to
do the verification after all needed data is read out?

Thanks,
Qu

>
> In case of a checksum failure (or a plain old I/O error), the repair
> is now kicked off before the upper level ->end_io handler is invoked.
> Tracking of the repair status is massively simplified by just keeping
> a small failed_bio structure per bio with failed sectors and otherwise
> using the information in the repair bio.  The per-inode I/O failure
> tree can be entirely removed.
>
> The saved bvec_iter in the btrfs_bio is now competely managed by
> btrfs_submit_bio and must not be accessed by the callers.
>
> There is one significant behavior change here:  If repair fails or
> is impossible to start with, the whole bio will be failed to the
> upper layer.  This is the behavior that all I/O submitters execept
> for buffered I/O already emulated in their end_io handler.  For
> buffered I/O this now means that a large readahead request can
> fail due to a single bad sector, but as readahead errors are igored
> the following readpage if the sector is actually accessed will
> still be able to read.  This also matches the I/O failure handling
> in other file systems.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   fs/btrfs/btrfs_inode.h       |   5 -
>   fs/btrfs/compression.c       |  54 +----
>   fs/btrfs/ctree.h             |  13 +-
>   fs/btrfs/extent-io-tree.h    |  18 --
>   fs/btrfs/extent_io.c         | 451 +----------------------------------
>   fs/btrfs/extent_io.h         |  28 ---
>   fs/btrfs/file-item.c         |  42 ++--
>   fs/btrfs/inode.c             | 320 ++++---------------------
>   fs/btrfs/volumes.c           | 238 ++++++++++++++++--
>   fs/btrfs/volumes.h           |  49 ++--
>   include/trace/events/btrfs.h |   1 -
>   11 files changed, 320 insertions(+), 899 deletions(-)
>
> diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
> index b160b8e124e01..4cb9898869019 100644
> --- a/fs/btrfs/btrfs_inode.h
> +++ b/fs/btrfs/btrfs_inode.h
> @@ -91,11 +91,6 @@ struct btrfs_inode {
>   	/* the io_tree does range state (DIRTY, LOCKED etc) */
>   	struct extent_io_tree io_tree;
>
> -	/* special utility tree used to record which mirrors have already been
> -	 * tried when checksums fail for a given block
> -	 */
> -	struct extent_io_tree io_failure_tree;
> -
>   	/*
>   	 * Keep track of where the inode has extent items mapped in order to
>   	 * make sure the i_size adjustments are accurate
> diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
> index 1c77de3239bc4..f932415a4f1df 100644
> --- a/fs/btrfs/compression.c
> +++ b/fs/btrfs/compression.c
> @@ -159,53 +159,15 @@ static void finish_compressed_bio_read(struct compressed_bio *cb)
>   	kfree(cb);
>   }
>
> -/*
> - * Verify the checksums and kick off repair if needed on the uncompressed data
> - * before decompressing it into the original bio and freeing the uncompressed
> - * pages.
> - */
>   static void end_compressed_bio_read(struct btrfs_bio *bbio)
>   {
>   	struct compressed_bio *cb = bbio->private;
> -	struct inode *inode = cb->inode;
> -	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> -	struct btrfs_inode *bi = BTRFS_I(inode);
> -	bool csum = !(bi->flags & BTRFS_INODE_NODATASUM) &&
> -		    !test_bit(BTRFS_FS_STATE_NO_CSUMS, &fs_info->fs_state);
> -	blk_status_t status = bbio->bio.bi_status;
> -	struct bvec_iter iter;
> -	struct bio_vec bv;
> -	u32 offset;
> -
> -	btrfs_bio_for_each_sector(fs_info, bv, bbio, iter, offset) {
> -		u64 start = bbio->file_offset + offset;
> -
> -		if (!status &&
> -		    (!csum || !btrfs_check_data_csum(inode, bbio, offset,
> -						     bv.bv_page, bv.bv_offset))) {
> -			clean_io_failure(fs_info, &bi->io_failure_tree,
> -					 &bi->io_tree, start, bv.bv_page,
> -					 btrfs_ino(bi), bv.bv_offset);
> -		} else {
> -			int ret;
> -
> -			refcount_inc(&cb->pending_ios);
> -			ret = btrfs_repair_one_sector(inode, bbio, offset,
> -						      bv.bv_page, bv.bv_offset,
> -						      btrfs_submit_data_read_bio);
> -			if (ret) {
> -				refcount_dec(&cb->pending_ios);
> -				status = errno_to_blk_status(ret);
> -			}
> -		}
> -	}
>
> -	if (status)
> -		cb->status = status;
> +	if (bbio->bio.bi_status)
> +		cb->status = bbio->bio.bi_status;
>
>   	if (refcount_dec_and_test(&cb->pending_ios))
>   		finish_compressed_bio_read(cb);
> -	btrfs_bio_free_csum(bbio);
>   	bio_put(&bbio->bio);
>   }
>
> @@ -342,7 +304,7 @@ static struct bio *alloc_compressed_bio(struct compressed_bio *cb, u64 disk_byte
>   	struct bio *bio;
>   	int ret;
>
> -	bio = btrfs_bio_alloc(BIO_MAX_VECS, opf, endio_func, cb);
> +	bio = btrfs_bio_alloc(BIO_MAX_VECS, opf, cb->inode, endio_func, cb);
>   	bio->bi_iter.bi_sector = disk_bytenr >> SECTOR_SHIFT;
>
>   	em = btrfs_get_chunk_map(fs_info, disk_bytenr, fs_info->sectorsize);
> @@ -778,10 +740,6 @@ void btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
>   			submit = true;
>
>   		if (submit) {
> -			/* Save the original iter for read repair */
> -			if (bio_op(comp_bio) == REQ_OP_READ)
> -				btrfs_bio(comp_bio)->iter = comp_bio->bi_iter;
> -
>   			/*
>   			 * Save the initial offset of this chunk, as there
>   			 * is no direct correlation between compressed pages and
> @@ -790,12 +748,6 @@ void btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
>   			 */
>   			btrfs_bio(comp_bio)->file_offset = file_offset;
>
> -			ret = btrfs_lookup_bio_sums(inode, comp_bio, NULL);
> -			if (ret) {
> -				btrfs_bio_end_io(btrfs_bio(comp_bio), ret);
> -				break;
> -			}
> -
>   			ASSERT(comp_bio->bi_iter.bi_size);
>   			btrfs_submit_bio(fs_info, comp_bio, mirror_num);
>   			comp_bio = NULL;
> diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> index 0069bc86c04f1..3dcb0d5f8faa0 100644
> --- a/fs/btrfs/ctree.h
> +++ b/fs/btrfs/ctree.h
> @@ -3344,7 +3344,7 @@ int btrfs_find_orphan_item(struct btrfs_root *root, u64 offset);
>   /* file-item.c */
>   int btrfs_del_csums(struct btrfs_trans_handle *trans,
>   		    struct btrfs_root *root, u64 bytenr, u64 len);
> -blk_status_t btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio, u8 *dst);
> +int btrfs_lookup_bio_sums(struct btrfs_bio *bbio);
>   int btrfs_insert_hole_extent(struct btrfs_trans_handle *trans,
>   			     struct btrfs_root *root, u64 objectid, u64 pos,
>   			     u64 num_bytes);
> @@ -3375,15 +3375,8 @@ u64 btrfs_file_extent_end(const struct btrfs_path *path);
>   void btrfs_submit_data_write_bio(struct inode *inode, struct bio *bio, int mirror_num);
>   void btrfs_submit_data_read_bio(struct inode *inode, struct bio *bio,
>   			int mirror_num, enum btrfs_compression_type compress_type);
> -int btrfs_check_sector_csum(struct btrfs_fs_info *fs_info, struct page *page,
> -			    u32 pgoff, u8 *csum, const u8 * const csum_expected);
> -int btrfs_check_data_csum(struct inode *inode, struct btrfs_bio *bbio,
> -			  u32 bio_offset, struct page *page, u32 pgoff);
> -unsigned int btrfs_verify_data_csum(struct btrfs_bio *bbio,
> -				    u32 bio_offset, struct page *page,
> -				    u64 start, u64 end);
> -int btrfs_check_data_csum(struct inode *inode, struct btrfs_bio *bbio,
> -			  u32 bio_offset, struct page *page, u32 pgoff);
> +bool btrfs_data_csum_ok(struct btrfs_bio *bbio, struct btrfs_device *dev,
> +			u32 bio_offset, struct bio_vec *bv);
>   struct extent_map *btrfs_get_extent_fiemap(struct btrfs_inode *inode,
>   					   u64 start, u64 len);
>   noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
> diff --git a/fs/btrfs/extent-io-tree.h b/fs/btrfs/extent-io-tree.h
> index e218bb56d86ac..a1afe6e15943e 100644
> --- a/fs/btrfs/extent-io-tree.h
> +++ b/fs/btrfs/extent-io-tree.h
> @@ -4,7 +4,6 @@
>   #define BTRFS_EXTENT_IO_TREE_H
>
>   struct extent_changeset;
> -struct io_failure_record;
>
>   /* Bits for the extent state */
>   #define EXTENT_DIRTY		(1U << 0)
> @@ -55,7 +54,6 @@ enum {
>   	IO_TREE_FS_EXCLUDED_EXTENTS,
>   	IO_TREE_BTREE_INODE_IO,
>   	IO_TREE_INODE_IO,
> -	IO_TREE_INODE_IO_FAILURE,
>   	IO_TREE_RELOC_BLOCKS,
>   	IO_TREE_TRANS_DIRTY_PAGES,
>   	IO_TREE_ROOT_DIRTY_LOG_PAGES,
> @@ -88,8 +86,6 @@ struct extent_state {
>   	refcount_t refs;
>   	u32 state;
>
> -	struct io_failure_record *failrec;
> -
>   #ifdef CONFIG_BTRFS_DEBUG
>   	struct list_head leak_list;
>   #endif
> @@ -246,18 +242,4 @@ bool btrfs_find_delalloc_range(struct extent_io_tree *tree, u64 *start,
>   			       u64 *end, u64 max_bytes,
>   			       struct extent_state **cached_state);
>
> -/* This should be reworked in the future and put elsewhere. */
> -struct io_failure_record *get_state_failrec(struct extent_io_tree *tree, u64 start);
> -int set_state_failrec(struct extent_io_tree *tree, u64 start,
> -		      struct io_failure_record *failrec);
> -void btrfs_free_io_failure_record(struct btrfs_inode *inode, u64 start,
> -		u64 end);
> -int free_io_failure(struct extent_io_tree *failure_tree,
> -		    struct extent_io_tree *io_tree,
> -		    struct io_failure_record *rec);
> -int clean_io_failure(struct btrfs_fs_info *fs_info,
> -		     struct extent_io_tree *failure_tree,
> -		     struct extent_io_tree *io_tree, u64 start,
> -		     struct page *page, u64 ino, unsigned int pg_offset);
> -
>   #endif /* BTRFS_EXTENT_IO_TREE_H */
> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> index c83cc5677a08a..d8c43e2111a99 100644
> --- a/fs/btrfs/extent_io.c
> +++ b/fs/btrfs/extent_io.c
> @@ -326,7 +326,6 @@ static struct extent_state *alloc_extent_state(gfp_t mask)
>   	if (!state)
>   		return state;
>   	state->state = 0;
> -	state->failrec = NULL;
>   	RB_CLEAR_NODE(&state->rb_node);
>   	btrfs_leak_debug_add(&leak_lock, &state->leak_list, &states);
>   	refcount_set(&state->refs, 1);
> @@ -2159,66 +2158,6 @@ u64 count_range_bits(struct extent_io_tree *tree,
>   	return total_bytes;
>   }
>
> -/*
> - * set the private field for a given byte offset in the tree.  If there isn't
> - * an extent_state there already, this does nothing.
> - */
> -int set_state_failrec(struct extent_io_tree *tree, u64 start,
> -		      struct io_failure_record *failrec)
> -{
> -	struct rb_node *node;
> -	struct extent_state *state;
> -	int ret = 0;
> -
> -	spin_lock(&tree->lock);
> -	/*
> -	 * this search will find all the extents that end after
> -	 * our range starts.
> -	 */
> -	node = tree_search(tree, start);
> -	if (!node) {
> -		ret = -ENOENT;
> -		goto out;
> -	}
> -	state = rb_entry(node, struct extent_state, rb_node);
> -	if (state->start != start) {
> -		ret = -ENOENT;
> -		goto out;
> -	}
> -	state->failrec = failrec;
> -out:
> -	spin_unlock(&tree->lock);
> -	return ret;
> -}
> -
> -struct io_failure_record *get_state_failrec(struct extent_io_tree *tree, u64 start)
> -{
> -	struct rb_node *node;
> -	struct extent_state *state;
> -	struct io_failure_record *failrec;
> -
> -	spin_lock(&tree->lock);
> -	/*
> -	 * this search will find all the extents that end after
> -	 * our range starts.
> -	 */
> -	node = tree_search(tree, start);
> -	if (!node) {
> -		failrec = ERR_PTR(-ENOENT);
> -		goto out;
> -	}
> -	state = rb_entry(node, struct extent_state, rb_node);
> -	if (state->start != start) {
> -		failrec = ERR_PTR(-ENOENT);
> -		goto out;
> -	}
> -
> -	failrec = state->failrec;
> -out:
> -	spin_unlock(&tree->lock);
> -	return failrec;
> -}
> -
>   /*
>    * searches a range in the state tree for a given mask.
>    * If 'filled' == 1, this returns 1 only if every extent in the tree
> @@ -2275,258 +2214,6 @@ int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
>   	return bitset;
>   }
>
> -int free_io_failure(struct extent_io_tree *failure_tree,
> -		    struct extent_io_tree *io_tree,
> -		    struct io_failure_record *rec)
> -{
> -	int ret;
> -
> -	set_state_failrec(failure_tree, rec->start, NULL);
> -	ret = clear_extent_bits(failure_tree, rec->start,
> -				rec->start + rec->len - 1,
> -				EXTENT_LOCKED | EXTENT_DIRTY);
> -	kfree(rec);
> -	return ret;
> -}
> -
> -static int next_mirror(const struct io_failure_record *failrec, int cur_mirror)
> -{
> -	if (cur_mirror == failrec->num_copies)
> -		return cur_mirror + 1 - failrec->num_copies;
> -	return cur_mirror + 1;
> -}
> -
> -static int prev_mirror(const struct io_failure_record *failrec, int cur_mirror)
> -{
> -	if (cur_mirror == 1)
> -		return failrec->num_copies;
> -	return cur_mirror - 1;
> -}
> -
> -/*
> - * each time an IO finishes, we do a fast check in the IO failure tree
> - * to see if we need to process or clean up an io_failure_record
> - */
> -int clean_io_failure(struct btrfs_fs_info *fs_info,
> -		     struct extent_io_tree *failure_tree,
> -		     struct extent_io_tree *io_tree, u64 start,
> -		     struct page *page, u64 ino, unsigned int pg_offset)
> -{
> -	u64 private;
> -	struct io_failure_record *failrec;
> -	struct extent_state *state;
> -	int mirror;
> -	int ret;
> -
> -	private = 0;
> -	ret = count_range_bits(failure_tree, &private, (u64)-1, 1,
> -			       EXTENT_DIRTY, 0);
> -	if (!ret)
> -		return 0;
> -
> -	failrec = get_state_failrec(failure_tree, start);
> -	if (IS_ERR(failrec))
> -		return 0;
> -
> -	BUG_ON(!failrec->this_mirror);
> -
> -	if (sb_rdonly(fs_info->sb))
> -		goto out;
> -
> -	spin_lock(&io_tree->lock);
> -	state = find_first_extent_bit_state(io_tree,
> -					    failrec->start,
> -					    EXTENT_LOCKED);
> -	spin_unlock(&io_tree->lock);
> -
> -	if (!state || state->start > failrec->start ||
> -	    state->end < failrec->start + failrec->len - 1)
> -		goto out;
> -
> -	mirror = failrec->this_mirror;
> -	do {
> -		mirror = prev_mirror(failrec, mirror);
> -		btrfs_repair_io_failure(fs_info, ino, start, failrec->len,
> -				  failrec->logical, page, pg_offset, mirror);
> -	} while (mirror != failrec->failed_mirror);
> -
> -out:
> -	free_io_failure(failure_tree, io_tree, failrec);
> -	return 0;
> -}
> -
> -/*
> - * Can be called when
> - * - hold extent lock
> - * - under ordered extent
> - * - the inode is freeing
> - */
> -void btrfs_free_io_failure_record(struct btrfs_inode *inode, u64 start, u64 end)
> -{
> -	struct extent_io_tree *failure_tree = &inode->io_failure_tree;
> -	struct io_failure_record *failrec;
> -	struct extent_state *state, *next;
> -
> -	if (RB_EMPTY_ROOT(&failure_tree->state))
> -		return;
> -
> -	spin_lock(&failure_tree->lock);
> -	state = find_first_extent_bit_state(failure_tree, start, EXTENT_DIRTY);
> -	while (state) {
> -		if (state->start > end)
> -			break;
> -
> -		ASSERT(state->end <= end);
> -
> -		next = next_state(state);
> -
> -		failrec = state->failrec;
> -		free_extent_state(state);
> -		kfree(failrec);
> -
> -		state = next;
> -	}
> -	spin_unlock(&failure_tree->lock);
> -}
> -
> -static struct io_failure_record *btrfs_get_io_failure_record(struct inode *inode,
> -							     struct btrfs_bio *bbio,
> -							     unsigned int bio_offset)
> -{
> -	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> -	u64 start = bbio->file_offset + bio_offset;
> -	struct io_failure_record *failrec;
> -	struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
> -	const u32 sectorsize = fs_info->sectorsize;
> -	int ret;
> -
> -	failrec = get_state_failrec(failure_tree, start);
> -	if (!IS_ERR(failrec)) {
> -		btrfs_debug(fs_info,
> -	"Get IO Failure Record: (found) logical=%llu, start=%llu, len=%llu",
> -			failrec->logical, failrec->start, failrec->len);
> -		/*
> -		 * when data can be on disk more than twice, add to failrec here
> -		 * (e.g. with a list for failed_mirror) to make
> -		 * clean_io_failure() clean all those errors at once.
> -		 */
> -		ASSERT(failrec->this_mirror == bbio->mirror_num);
> -		ASSERT(failrec->len == fs_info->sectorsize);
> -		return failrec;
> -	}
> -
> -	failrec = kzalloc(sizeof(*failrec), GFP_NOFS);
> -	if (!failrec)
> -		return ERR_PTR(-ENOMEM);
> -
> -	failrec->start = start;
> -	failrec->len = sectorsize;
> -	failrec->failed_mirror = bbio->mirror_num;
> -	failrec->this_mirror = bbio->mirror_num;
> -	failrec->logical = (bbio->iter.bi_sector << SECTOR_SHIFT) + bio_offset;
> -
> -	btrfs_debug(fs_info,
> -		    "new io failure record logical %llu start %llu",
> -		    failrec->logical, start);
> -
> -	failrec->num_copies = btrfs_num_copies(fs_info, failrec->logical, sectorsize);
> -	if (failrec->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,
> -			"cannot repair logical %llu num_copies %d",
> -			failrec->logical, failrec->num_copies);
> -		kfree(failrec);
> -		return ERR_PTR(-EIO);
> -	}
> -
> -	/* Set the bits in the private failure tree */
> -	ret = set_extent_bits(failure_tree, start, start + sectorsize - 1,
> -			      EXTENT_LOCKED | EXTENT_DIRTY);
> -	if (ret >= 0) {
> -		ret = set_state_failrec(failure_tree, start, failrec);
> -	} else if (ret < 0) {
> -		kfree(failrec);
> -		return ERR_PTR(ret);
> -	}
> -
> -	return failrec;
> -}
> -
> -int btrfs_repair_one_sector(struct inode *inode, struct btrfs_bio *failed_bbio,
> -			    u32 bio_offset, struct page *page, unsigned int pgoff,
> -			    submit_bio_hook_t *submit_bio_hook)
> -{
> -	u64 start = failed_bbio->file_offset + bio_offset;
> -	struct io_failure_record *failrec;
> -	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 bio *failed_bio = &failed_bbio->bio;
> -	const int icsum = bio_offset >> fs_info->sectorsize_bits;
> -	struct bio *repair_bio;
> -	struct btrfs_bio *repair_bbio;
> -
> -	btrfs_debug(fs_info,
> -		   "repair read error: read error at %llu", start);
> -
> -	BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
> -
> -	failrec = btrfs_get_io_failure_record(inode, failed_bbio, bio_offset);
> -	if (IS_ERR(failrec))
> -		return PTR_ERR(failrec);
> -
> -	/*
> -	 * There are two premises:
> -	 * a) deliver good data to the caller
> -	 * b) correct the bad sectors on disk
> -	 *
> -	 * Since we're only doing repair for one sector, we only need to get
> -	 * a good copy of the failed sector and if we succeed, we have setup
> -	 * everything for btrfs_repair_io_failure to do the rest for us.
> -	 */
> -	failrec->this_mirror = next_mirror(failrec, failrec->this_mirror);
> -	if (failrec->this_mirror == failrec->failed_mirror) {
> -		btrfs_debug(fs_info,
> -			"failed to repair num_copies %d this_mirror %d failed_mirror %d",
> -			failrec->num_copies, failrec->this_mirror, failrec->failed_mirror);
> -		free_io_failure(failure_tree, tree, failrec);
> -		return -EIO;
> -	}
> -
> -	repair_bio = btrfs_bio_alloc(1, REQ_OP_READ, failed_bbio->end_io,
> -				     failed_bbio->private);
> -	repair_bbio = btrfs_bio(repair_bio);
> -	repair_bbio->file_offset = start;
> -	repair_bio->bi_iter.bi_sector = failrec->logical >> 9;
> -
> -	if (failed_bbio->csum) {
> -		const u32 csum_size = fs_info->csum_size;
> -
> -		repair_bbio->csum = repair_bbio->csum_inline;
> -		memcpy(repair_bbio->csum,
> -		       failed_bbio->csum + csum_size * icsum, csum_size);
> -	}
> -
> -	bio_add_page(repair_bio, page, failrec->len, pgoff);
> -	repair_bbio->iter = repair_bio->bi_iter;
> -
> -	btrfs_debug(btrfs_sb(inode->i_sb),
> -		    "repair read error: submitting new read to mirror %d",
> -		    failrec->this_mirror);
> -
> -	/*
> -	 * At this point we have a bio, so any errors from submit_bio_hook()
> -	 * will be handled by the endio on the repair_bio, so we can't return an
> -	 * error here.
> -	 */
> -	submit_bio_hook(inode, repair_bio, failrec->this_mirror, 0);
> -	return BLK_STS_OK;
> -}
> -
>   static void end_page_read(struct page *page, bool uptodate, u64 start, u32 len)
>   {
>   	struct btrfs_fs_info *fs_info = btrfs_sb(page->mapping->host->i_sb);
> @@ -2555,84 +2242,6 @@ static void end_page_read(struct page *page, bool uptodate, u64 start, u32 len)
>   		btrfs_subpage_end_reader(fs_info, page, start, len);
>   }
>
> -static void end_sector_io(struct page *page, u64 offset, bool uptodate)
> -{
> -	struct btrfs_inode *inode = BTRFS_I(page->mapping->host);
> -	const u32 sectorsize = inode->root->fs_info->sectorsize;
> -	struct extent_state *cached = NULL;
> -
> -	end_page_read(page, uptodate, offset, sectorsize);
> -	if (uptodate)
> -		set_extent_uptodate(&inode->io_tree, offset,
> -				    offset + sectorsize - 1, &cached, GFP_ATOMIC);
> -	unlock_extent_cached_atomic(&inode->io_tree, offset,
> -				    offset + sectorsize - 1, &cached);
> -}
> -
> -static void submit_data_read_repair(struct inode *inode,
> -				    struct btrfs_bio *failed_bbio,
> -				    u32 bio_offset, const struct bio_vec *bvec,
> -				    unsigned int error_bitmap)
> -{
> -	const unsigned int pgoff = bvec->bv_offset;
> -	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> -	struct page *page = bvec->bv_page;
> -	const u64 start = page_offset(bvec->bv_page) + bvec->bv_offset;
> -	const u64 end = start + bvec->bv_len - 1;
> -	const u32 sectorsize = fs_info->sectorsize;
> -	const int nr_bits = (end + 1 - start) >> fs_info->sectorsize_bits;
> -	int i;
> -
> -	BUG_ON(bio_op(&failed_bbio->bio) == REQ_OP_WRITE);
> -
> -	/* This repair is only for data */
> -	ASSERT(is_data_inode(inode));
> -
> -	/* We're here because we had some read errors or csum mismatch */
> -	ASSERT(error_bitmap);
> -
> -	/*
> -	 * We only get called on buffered IO, thus page must be mapped and bio
> -	 * must not be cloned.
> -	 */
> -	ASSERT(page->mapping && !bio_flagged(&failed_bbio->bio, BIO_CLONED));
> -
> -	/* Iterate through all the sectors in the range */
> -	for (i = 0; i < nr_bits; i++) {
> -		const unsigned int offset = i * sectorsize;
> -		bool uptodate = false;
> -		int ret;
> -
> -		if (!(error_bitmap & (1U << i))) {
> -			/*
> -			 * This sector has no error, just end the page read
> -			 * and unlock the range.
> -			 */
> -			uptodate = true;
> -			goto next;
> -		}
> -
> -		ret = btrfs_repair_one_sector(inode, failed_bbio,
> -				bio_offset + offset, page, pgoff + offset,
> -				btrfs_submit_data_read_bio);
> -		if (!ret) {
> -			/*
> -			 * We have submitted the read repair, the page release
> -			 * will be handled by the endio function of the
> -			 * submitted repair bio.
> -			 * Thus we don't need to do any thing here.
> -			 */
> -			continue;
> -		}
> -		/*
> -		 * Continue on failed repair, otherwise the remaining sectors
> -		 * will not be properly unlocked.
> -		 */
> -next:
> -		end_sector_io(page, start + offset, uptodate);
> -	}
> -}
> -
>   /* lots and lots of room for performance fixes in the end_bio funcs */
>
>   void end_extent_writepage(struct page *page, int err, u64 start, u64 end)
> @@ -2835,7 +2444,6 @@ static void end_bio_extent_readpage(struct btrfs_bio *bbio)
>   {
>   	struct bio *bio = &bbio->bio;
>   	struct bio_vec *bvec;
> -	struct extent_io_tree *tree, *failure_tree;
>   	struct processed_extent processed = { 0 };
>   	/*
>   	 * The offset to the beginning of a bio, since one bio can never be
> @@ -2852,8 +2460,6 @@ static void end_bio_extent_readpage(struct btrfs_bio *bbio)
>   		struct inode *inode = page->mapping->host;
>   		struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
>   		const u32 sectorsize = fs_info->sectorsize;
> -		unsigned int error_bitmap = (unsigned int)-1;
> -		bool repair = false;
>   		u64 start;
>   		u64 end;
>   		u32 len;
> @@ -2862,8 +2468,6 @@ static void end_bio_extent_readpage(struct btrfs_bio *bbio)
>   			"end_bio_extent_readpage: bi_sector=%llu, err=%d, mirror=%u",
>   			bio->bi_iter.bi_sector, bio->bi_status,
>   			bbio->mirror_num);
> -		tree = &BTRFS_I(inode)->io_tree;
> -		failure_tree = &BTRFS_I(inode)->io_failure_tree;
>
>   		/*
>   		 * We always issue full-sector reads, but if some block in a
> @@ -2887,27 +2491,15 @@ static void end_bio_extent_readpage(struct btrfs_bio *bbio)
>   		len = bvec->bv_len;
>
>   		mirror = bbio->mirror_num;
> -		if (likely(uptodate)) {
> -			if (is_data_inode(inode)) {
> -				error_bitmap = btrfs_verify_data_csum(bbio,
> -						bio_offset, page, start, end);
> -				if (error_bitmap)
> -					uptodate = false;
> -			} else {
> -				if (btrfs_validate_metadata_buffer(bbio,
> -						page, start, end, mirror))
> -					uptodate = false;
> -			}
> -		}
> +		if (uptodate && !is_data_inode(inode) &&
> +		    btrfs_validate_metadata_buffer(bbio, page, start, end,
> +						   mirror))
> +			uptodate = false;
>
>   		if (likely(uptodate)) {
>   			loff_t i_size = i_size_read(inode);
>   			pgoff_t end_index = i_size >> PAGE_SHIFT;
>
> -			clean_io_failure(BTRFS_I(inode)->root->fs_info,
> -					 failure_tree, tree, start, page,
> -					 btrfs_ino(BTRFS_I(inode)), 0);
> -
>   			/*
>   			 * Zero out the remaining part if this range straddles
>   			 * i_size.
> @@ -2924,19 +2516,7 @@ static void end_bio_extent_readpage(struct btrfs_bio *bbio)
>   				zero_user_segment(page, zero_start,
>   						  offset_in_page(end) + 1);
>   			}
> -		} else if (is_data_inode(inode)) {
> -			/*
> -			 * Only try to repair bios that actually made it to a
> -			 * device.  If the bio failed to be submitted mirror
> -			 * is 0 and we need to fail it without retrying.
> -			 *
> -			 * This also includes the high level bios for compressed
> -			 * extents - these never make it to a device and repair
> -			 * is already handled on the lower compressed bio.
> -			 */
> -			if (mirror > 0)
> -				repair = true;
> -		} else {
> +		} else if (!is_data_inode(inode)) {
>   			struct extent_buffer *eb;
>
>   			eb = find_extent_buffer_readpage(fs_info, page, start);
> @@ -2945,19 +2525,10 @@ static void end_bio_extent_readpage(struct btrfs_bio *bbio)
>   			atomic_dec(&eb->io_pages);
>   		}
>
> -		if (repair) {
> -			/*
> -			 * submit_data_read_repair() will handle all the good
> -			 * and bad sectors, we just continue to the next bvec.
> -			 */
> -			submit_data_read_repair(inode, bbio, bio_offset, bvec,
> -						error_bitmap);
> -		} else {
> -			/* Update page status and unlock */
> -			end_page_read(page, uptodate, start, len);
> -			endio_readpage_release_extent(&processed, BTRFS_I(inode),
> -					start, end, PageUptodate(page));
> -		}
> +		/* Update page status and unlock */
> +		end_page_read(page, uptodate, start, len);
> +		endio_readpage_release_extent(&processed, BTRFS_I(inode),
> +				start, end, PageUptodate(page));
>
>   		ASSERT(bio_offset + len > bio_offset);
>   		bio_offset += len;
> @@ -2965,7 +2536,6 @@ static void end_bio_extent_readpage(struct btrfs_bio *bbio)
>   	}
>   	/* Release the last extent */
>   	endio_readpage_release_extent(&processed, NULL, 0, 0, false);
> -	btrfs_bio_free_csum(bbio);
>   	bio_put(bio);
>   }
>
> @@ -3158,7 +2728,8 @@ static int alloc_new_bio(struct btrfs_inode *inode,
>   	struct bio *bio;
>   	int ret;
>
> -	bio = btrfs_bio_alloc(BIO_MAX_VECS, opf, end_io_func, NULL);
> +	bio = btrfs_bio_alloc(BIO_MAX_VECS, opf, &inode->vfs_inode, end_io_func,
> +			      NULL);
>   	/*
>   	 * For compressed page range, its disk_bytenr is always @disk_bytenr
>   	 * passed in, no matter if we have added any range into previous bio.
> diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
> index e653e64598bf7..caf3343d1a36c 100644
> --- a/fs/btrfs/extent_io.h
> +++ b/fs/btrfs/extent_io.h
> @@ -57,17 +57,11 @@ enum {
>   #define BITMAP_LAST_BYTE_MASK(nbits) \
>   	(BYTE_MASK >> (-(nbits) & (BITS_PER_BYTE - 1)))
>
> -struct btrfs_bio;
>   struct btrfs_root;
>   struct btrfs_inode;
>   struct btrfs_fs_info;
> -struct io_failure_record;
>   struct extent_io_tree;
>
> -typedef void (submit_bio_hook_t)(struct inode *inode, struct bio *bio,
> -					 int mirror_num,
> -					 enum btrfs_compression_type compress_type);
> -
>   typedef blk_status_t (extent_submit_bio_start_t)(struct inode *inode,
>   		struct bio *bio, u64 dio_file_offset);
>
> @@ -244,28 +238,6 @@ int btrfs_alloc_page_array(unsigned int nr_pages, struct page **page_array);
>
>   void end_extent_writepage(struct page *page, int err, u64 start, u64 end);
>
> -/*
> - * When IO fails, either with EIO or csum verification fails, we
> - * try other mirrors that might have a good copy of the data.  This
> - * io_failure_record is used to record state as we go through all the
> - * mirrors.  If another mirror has good data, the sector is set up to date
> - * and things continue.  If a good mirror can't be found, the original
> - * bio end_io callback is called to indicate things have failed.
> - */
> -struct io_failure_record {
> -	struct page *page;
> -	u64 start;
> -	u64 len;
> -	u64 logical;
> -	int this_mirror;
> -	int failed_mirror;
> -	int num_copies;
> -};
> -
> -int btrfs_repair_one_sector(struct inode *inode, struct btrfs_bio *failed_bbio,
> -			    u32 bio_offset, struct page *page, unsigned int pgoff,
> -			    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,
> diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
> index 29999686d234c..ffbac8f257908 100644
> --- a/fs/btrfs/file-item.c
> +++ b/fs/btrfs/file-item.c
> @@ -359,27 +359,27 @@ static int search_file_offset_in_bio(struct bio *bio, struct inode *inode,
>    *       NULL, the checksum buffer is allocated and returned in
>    *       btrfs_bio(bio)->csum instead.
>    *
> - * Return: BLK_STS_RESOURCE if allocating memory fails, BLK_STS_OK otherwise.
> + * Return: -ENOMEM if allocating memory fails, 0 otherwise.
>    */
> -blk_status_t btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio, u8 *dst)
> +int btrfs_lookup_bio_sums(struct btrfs_bio *bbio)
>   {
> +	struct inode *inode = bbio->inode;
>   	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
>   	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
> -	struct btrfs_bio *bbio = NULL;
> +	struct bio *bio = &bbio->bio;
>   	struct btrfs_path *path;
>   	const u32 sectorsize = fs_info->sectorsize;
>   	const u32 csum_size = fs_info->csum_size;
>   	u32 orig_len = bio->bi_iter.bi_size;
>   	u64 orig_disk_bytenr = bio->bi_iter.bi_sector << SECTOR_SHIFT;
>   	u64 cur_disk_bytenr;
> -	u8 *csum;
>   	const unsigned int nblocks = orig_len >> fs_info->sectorsize_bits;
>   	int count = 0;
> -	blk_status_t ret = BLK_STS_OK;
> +	int ret = 0;
>
>   	if ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM) ||
>   	    test_bit(BTRFS_FS_STATE_NO_CSUMS, &fs_info->fs_state))
> -		return BLK_STS_OK;
> +		return 0;
>
>   	/*
>   	 * This function is only called for read bio.
> @@ -396,23 +396,16 @@ blk_status_t btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio, u8 *dst
>   	ASSERT(bio_op(bio) == REQ_OP_READ);
>   	path = btrfs_alloc_path();
>   	if (!path)
> -		return BLK_STS_RESOURCE;
> -
> -	if (!dst) {
> -		bbio = btrfs_bio(bio);
> +		return -ENOMEM;
>
> -		if (nblocks * csum_size > BTRFS_BIO_INLINE_CSUM_SIZE) {
> -			bbio->csum = kmalloc_array(nblocks, csum_size, GFP_NOFS);
> -			if (!bbio->csum) {
> -				btrfs_free_path(path);
> -				return BLK_STS_RESOURCE;
> -			}
> -		} else {
> -			bbio->csum = bbio->csum_inline;
> +	if (nblocks * csum_size > BTRFS_BIO_INLINE_CSUM_SIZE) {
> +		bbio->csum = kmalloc_array(nblocks, csum_size, GFP_NOFS);
> +		if (!bbio->csum) {
> +			btrfs_free_path(path);
> +			return -ENOMEM;
>   		}
> -		csum = bbio->csum;
>   	} else {
> -		csum = dst;
> +		bbio->csum = bbio->csum_inline;
>   	}
>
>   	/*
> @@ -451,14 +444,15 @@ blk_status_t btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio, u8 *dst
>   		ASSERT(cur_disk_bytenr - orig_disk_bytenr < UINT_MAX);
>   		sector_offset = (cur_disk_bytenr - orig_disk_bytenr) >>
>   				fs_info->sectorsize_bits;
> -		csum_dst = csum + sector_offset * csum_size;
> +		csum_dst = bbio->csum + sector_offset * csum_size;
>
>   		count = search_csum_tree(fs_info, path, cur_disk_bytenr,
>   					 search_len, csum_dst);
>   		if (count < 0) {
> -			ret = errno_to_blk_status(count);
> -			if (bbio)
> -				btrfs_bio_free_csum(bbio);
> +			ret = count;
> +			if (bbio->csum != bbio->csum_inline)
> +				kfree(bbio->csum);
> +			bbio->csum = NULL;
>   			break;
>   		}
>
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index b9d40e25d978c..b3466015008c7 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -85,9 +85,6 @@ struct btrfs_dio_private {
>   	 */
>   	refcount_t refs;
>
> -	/* Array of checksums */
> -	u8 *csums;
> -
>   	/* This must be last */
>   	struct bio bio;
>   };
> @@ -2735,9 +2732,6 @@ void btrfs_submit_data_write_bio(struct inode *inode, struct bio *bio, int mirro
>   void btrfs_submit_data_read_bio(struct inode *inode, struct bio *bio,
>   			int mirror_num, enum btrfs_compression_type compress_type)
>   {
> -	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> -	blk_status_t ret;
> -
>   	if (compress_type != BTRFS_COMPRESS_NONE) {
>   		/*
>   		 * btrfs_submit_compressed_read will handle completing the bio
> @@ -2747,20 +2741,7 @@ void btrfs_submit_data_read_bio(struct inode *inode, struct bio *bio,
>   		return;
>   	}
>
> -	/* Save the original iter for read repair */
> -	btrfs_bio(bio)->iter = bio->bi_iter;
> -
> -	/*
> -	 * Lookup bio sums does extra checks around whether we need to csum or
> -	 * not, which is why we ignore skip_sum here.
> -	 */
> -	ret = btrfs_lookup_bio_sums(inode, bio, NULL);
> -	if (ret) {
> -		btrfs_bio_end_io(btrfs_bio(bio), ret);
> -		return;
> -	}
> -
> -	btrfs_submit_bio(fs_info, bio, mirror_num);
> +	btrfs_submit_bio(btrfs_sb(inode->i_sb), bio, mirror_num);
>   }
>
>   /*
> @@ -3238,8 +3219,6 @@ int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
>   					ordered_extent->disk_num_bytes);
>   	}
>
> -	btrfs_free_io_failure_record(inode, start, end);
> -
>   	if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered_extent->flags)) {
>   		truncated = true;
>   		logical_len = ordered_extent->truncated_len;
> @@ -3417,133 +3396,64 @@ void btrfs_writepage_endio_finish_ordered(struct btrfs_inode *inode,
>   }
>
>   /*
> - * Verify the checksum for a single sector without any extra action that depend
> - * on the type of I/O.
> + * btrfs_data_csum_ok - verify the checksum of single data sector
> + * @bbio:	btrfs_io_bio which contains the csum
> + * @dev:	device the sector is on
> + * @bio_offset:	offset to the beginning of the bio (in bytes)
> + * @bv:		bio_vec to check
> + *
> + * Check if the checksum on a data block is valid.  When a checksum mismatch is
> + * detected, report the error and fill the corrupted range with zero.
> + *
> + * Return %true if the sector is ok or had no checksum to start with, else
> + * %false.
>    */
> -int btrfs_check_sector_csum(struct btrfs_fs_info *fs_info, struct page *page,
> -			    u32 pgoff, u8 *csum, const u8 * const csum_expected)
> +bool btrfs_data_csum_ok(struct btrfs_bio *bbio, struct btrfs_device *dev,
> +			u32 bio_offset, struct bio_vec *bv)
>   {
> +	struct btrfs_fs_info *fs_info = btrfs_sb(bbio->inode->i_sb);
> +	struct btrfs_inode *bi = BTRFS_I(bbio->inode);
> +	u64 file_offset = bbio->file_offset + bio_offset;
> +	u64 end = file_offset + bv->bv_len - 1;
>   	SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
> +	u8 *csum_expected;
> +	u8 csum[BTRFS_CSUM_SIZE];
>   	char *kaddr;
>
> -	ASSERT(pgoff + fs_info->sectorsize <= PAGE_SIZE);
> +	ASSERT(bv->bv_len == fs_info->sectorsize);
> +
> +	if (!bbio->csum)
> +		return true;
> +
> +	if (btrfs_is_data_reloc_root(bi->root) &&
> +	    test_range_bit(&bi->io_tree, file_offset, end, EXTENT_NODATASUM,
> +			1, NULL)) {
> +		/* Skip the range without csum for data reloc inode */
> +		clear_extent_bits(&bi->io_tree, file_offset, end,
> +				  EXTENT_NODATASUM);
> +		return true;
> +	}
> +
> +	csum_expected = btrfs_csum_ptr(fs_info, bbio->csum, bio_offset);
>
>   	shash->tfm = fs_info->csum_shash;
>
> -	kaddr = kmap_local_page(page) + pgoff;
> +	kaddr = bvec_kmap_local(bv);
>   	crypto_shash_digest(shash, kaddr, fs_info->sectorsize, csum);
>   	kunmap_local(kaddr);
>
>   	if (memcmp(csum, csum_expected, fs_info->csum_size))
> -		return -EIO;
> -	return 0;
> -}
> -
> -/*
> - * check_data_csum - verify checksum of one sector of uncompressed data
> - * @inode:	inode
> - * @bbio:	btrfs_bio which contains the csum
> - * @bio_offset:	offset to the beginning of the bio (in bytes)
> - * @page:	page where is the data to be verified
> - * @pgoff:	offset inside the page
> - *
> - * The length of such check is always one sector size.
> - *
> - * When csum mismatch is detected, we will also report the error and fill the
> - * corrupted range with zero. (Thus it needs the extra parameters)
> - */
> -int btrfs_check_data_csum(struct inode *inode, struct btrfs_bio *bbio,
> -			  u32 bio_offset, struct page *page, u32 pgoff)
> -{
> -	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> -	u32 len = fs_info->sectorsize;
> -	u8 *csum_expected;
> -	u8 csum[BTRFS_CSUM_SIZE];
> -
> -	ASSERT(pgoff + len <= PAGE_SIZE);
> -
> -	csum_expected = btrfs_csum_ptr(fs_info, bbio->csum, bio_offset);
> -
> -	if (btrfs_check_sector_csum(fs_info, page, pgoff, csum, csum_expected))
>   		goto zeroit;
> -	return 0;
> +	return true;
>
>   zeroit:
> -	btrfs_print_data_csum_error(BTRFS_I(inode),
> -				    bbio->file_offset + bio_offset,
> -				    csum, csum_expected, bbio->mirror_num);
> -	if (bbio->device)
> -		btrfs_dev_stat_inc_and_print(bbio->device,
> +	btrfs_print_data_csum_error(BTRFS_I(bbio->inode), file_offset, csum,
> +				    csum_expected, bbio->mirror_num);
> +	if (dev)
> +		btrfs_dev_stat_inc_and_print(dev,
>   					     BTRFS_DEV_STAT_CORRUPTION_ERRS);
> -	memzero_page(page, pgoff, len);
> -	return -EIO;
> -}
> -
> -/*
> - * When reads are done, we need to check csums to verify the data is correct.
> - * if there's a match, we allow the bio to finish.  If not, the code in
> - * extent_io.c will try to find good copies for us.
> - *
> - * @bio_offset:	offset to the beginning of the bio (in bytes)
> - * @start:	file offset of the range start
> - * @end:	file offset of the range end (inclusive)
> - *
> - * Return a bitmap where bit set means a csum mismatch, and bit not set means
> - * csum match.
> - */
> -unsigned int btrfs_verify_data_csum(struct btrfs_bio *bbio,
> -				    u32 bio_offset, struct page *page,
> -				    u64 start, u64 end)
> -{
> -	struct inode *inode = page->mapping->host;
> -	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> -	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
> -	struct btrfs_root *root = BTRFS_I(inode)->root;
> -	const u32 sectorsize = root->fs_info->sectorsize;
> -	u32 pg_off;
> -	unsigned int result = 0;
> -
> -	/*
> -	 * This only happens for NODATASUM or compressed read.
> -	 * Normally this should be covered by above check for compressed read
> -	 * or the next check for NODATASUM.  Just do a quicker exit here.
> -	 */
> -	if (bbio->csum == NULL)
> -		return 0;
> -
> -	if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
> -		return 0;
> -
> -	if (unlikely(test_bit(BTRFS_FS_STATE_NO_CSUMS, &fs_info->fs_state)))
> -		return 0;
> -
> -	ASSERT(page_offset(page) <= start &&
> -	       end <= page_offset(page) + PAGE_SIZE - 1);
> -	for (pg_off = offset_in_page(start);
> -	     pg_off < offset_in_page(end);
> -	     pg_off += sectorsize, bio_offset += sectorsize) {
> -		u64 file_offset = pg_off + page_offset(page);
> -		int ret;
> -
> -		if (btrfs_is_data_reloc_root(root) &&
> -		    test_range_bit(io_tree, file_offset,
> -				   file_offset + sectorsize - 1,
> -				   EXTENT_NODATASUM, 1, NULL)) {
> -			/* Skip the range without csum for data reloc inode */
> -			clear_extent_bits(io_tree, file_offset,
> -					  file_offset + sectorsize - 1,
> -					  EXTENT_NODATASUM);
> -			continue;
> -		}
> -		ret = btrfs_check_data_csum(inode, bbio, bio_offset, page, pg_off);
> -		if (ret < 0) {
> -			const int nr_bit = (pg_off - offset_in_page(start)) >>
> -				     root->fs_info->sectorsize_bits;
> -
> -			result |= (1U << nr_bit);
> -		}
> -	}
> -	return result;
> +	memzero_bvec(bv);
> +	return false;
>   }
>
>   /*
> @@ -5437,8 +5347,6 @@ void btrfs_evict_inode(struct inode *inode)
>   	if (is_bad_inode(inode))
>   		goto no_delete;
>
> -	btrfs_free_io_failure_record(BTRFS_I(inode), 0, (u64)-1);
> -
>   	if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
>   		goto no_delete;
>
> @@ -7974,60 +7882,9 @@ static void btrfs_dio_private_put(struct btrfs_dio_private *dip)
>   			      dip->file_offset + dip->bytes - 1);
>   	}
>
> -	kfree(dip->csums);
>   	bio_endio(&dip->bio);
>   }
>
> -static void submit_dio_repair_bio(struct inode *inode, struct bio *bio,
> -				  int mirror_num,
> -				  enum btrfs_compression_type compress_type)
> -{
> -	struct btrfs_dio_private *dip = btrfs_bio(bio)->private;
> -	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> -
> -	BUG_ON(bio_op(bio) == REQ_OP_WRITE);
> -
> -	refcount_inc(&dip->refs);
> -	btrfs_submit_bio(fs_info, bio, mirror_num);
> -}
> -
> -static blk_status_t btrfs_check_read_dio_bio(struct btrfs_dio_private *dip,
> -					     struct btrfs_bio *bbio,
> -					     const bool uptodate)
> -{
> -	struct inode *inode = dip->inode;
> -	struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
> -	struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
> -	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
> -	const bool csum = !(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM);
> -	blk_status_t err = BLK_STS_OK;
> -	struct bvec_iter iter;
> -	struct bio_vec bv;
> -	u32 offset;
> -
> -	btrfs_bio_for_each_sector(fs_info, bv, bbio, iter, offset) {
> -		u64 start = bbio->file_offset + offset;
> -
> -		if (uptodate &&
> -		    (!csum || !btrfs_check_data_csum(inode, bbio, offset, bv.bv_page,
> -					       bv.bv_offset))) {
> -			clean_io_failure(fs_info, failure_tree, io_tree, start,
> -					 bv.bv_page, btrfs_ino(BTRFS_I(inode)),
> -					 bv.bv_offset);
> -		} else {
> -			int ret;
> -
> -			ret = btrfs_repair_one_sector(inode, bbio, offset,
> -					bv.bv_page, bv.bv_offset,
> -					submit_dio_repair_bio);
> -			if (ret)
> -				err = errno_to_blk_status(ret);
> -		}
> -	}
> -
> -	return err;
> -}
> -
>   static blk_status_t btrfs_submit_bio_start_direct_io(struct inode *inode,
>   						     struct bio *bio,
>   						     u64 dio_file_offset)
> @@ -8041,18 +7898,14 @@ static void btrfs_end_dio_bio(struct btrfs_bio *bbio)
>   	struct bio *bio = &bbio->bio;
>   	blk_status_t err = bio->bi_status;
>
> -	if (err)
> +	if (err) {
>   		btrfs_warn(BTRFS_I(dip->inode)->root->fs_info,
>   			   "direct IO failed ino %llu rw %d,%u sector %#Lx len %u err no %d",
>   			   btrfs_ino(BTRFS_I(dip->inode)), bio_op(bio),
>   			   bio->bi_opf, bio->bi_iter.bi_sector,
>   			   bio->bi_iter.bi_size, err);
> -
> -	if (bio_op(bio) == REQ_OP_READ)
> -		err = btrfs_check_read_dio_bio(dip, bbio, !err);
> -
> -	if (err)
>   		dip->bio.bi_status = err;
> +	}
>
>   	btrfs_record_physical_zoned(dip->inode, bbio->file_offset, bio);
>
> @@ -8064,13 +7917,8 @@ static void btrfs_submit_dio_bio(struct bio *bio, struct inode *inode,
>   				 u64 file_offset, int async_submit)
>   {
>   	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> -	struct btrfs_dio_private *dip = btrfs_bio(bio)->private;
>   	blk_status_t ret;
> -
> -	/* Save the original iter for read repair */
> -	if (btrfs_op(bio) == BTRFS_MAP_READ)
> -		btrfs_bio(bio)->iter = bio->bi_iter;
> -
> +
>   	if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
>   		goto map;
>
> @@ -8090,9 +7938,6 @@ static void btrfs_submit_dio_bio(struct bio *bio, struct inode *inode,
>   			btrfs_bio_end_io(btrfs_bio(bio), ret);
>   			return;
>   		}
> -	} else {
> -		btrfs_bio(bio)->csum = btrfs_csum_ptr(fs_info, dip->csums,
> -						      file_offset - dip->file_offset);
>   	}
>   map:
>   	btrfs_submit_bio(fs_info, bio, 0);
> @@ -8104,7 +7949,6 @@ static void btrfs_submit_direct(const struct iomap_iter *iter,
>   	struct btrfs_dio_private *dip =
>   		container_of(dio_bio, struct btrfs_dio_private, bio);
>   	struct inode *inode = iter->inode;
> -	const bool write = (btrfs_op(dio_bio) == BTRFS_MAP_WRITE);
>   	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
>   	const bool raid56 = (btrfs_data_alloc_profile(fs_info) &
>   			     BTRFS_BLOCK_GROUP_RAID56_MASK);
> @@ -8125,25 +7969,6 @@ static void btrfs_submit_direct(const struct iomap_iter *iter,
>   	dip->file_offset = file_offset;
>   	dip->bytes = dio_bio->bi_iter.bi_size;
>   	refcount_set(&dip->refs, 1);
> -	dip->csums = NULL;
> -
> -	if (!write && !(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
> -		unsigned int nr_sectors =
> -			(dio_bio->bi_iter.bi_size >> fs_info->sectorsize_bits);
> -
> -		/*
> -		 * Load the csums up front to reduce csum tree searches and
> -		 * contention when submitting bios.
> -		 */
> -		status = BLK_STS_RESOURCE;
> -		dip->csums = kcalloc(nr_sectors, fs_info->csum_size, GFP_NOFS);
> -		if (!dip)
> -			goto out_err;
> -
> -		status = btrfs_lookup_bio_sums(inode, dio_bio, dip->csums);
> -		if (status != BLK_STS_OK)
> -			goto out_err;
> -	}
>
>   	start_sector = dio_bio->bi_iter.bi_sector;
>   	submit_len = dio_bio->bi_iter.bi_size;
> @@ -8171,7 +7996,7 @@ static void btrfs_submit_direct(const struct iomap_iter *iter,
>   		 * the allocation is backed by btrfs_bioset.
>   		 */
>   		bio = btrfs_bio_clone_partial(dio_bio, clone_offset, clone_len,
> -					      btrfs_end_dio_bio, dip);
> +					      inode, btrfs_end_dio_bio, dip);
>   		btrfs_bio(bio)->file_offset = file_offset;
>
>   		if (bio_op(bio) == REQ_OP_ZONE_APPEND) {
> @@ -8918,12 +8743,9 @@ struct inode *btrfs_alloc_inode(struct super_block *sb)
>   	inode = &ei->vfs_inode;
>   	extent_map_tree_init(&ei->extent_tree);
>   	extent_io_tree_init(fs_info, &ei->io_tree, IO_TREE_INODE_IO, inode);
> -	extent_io_tree_init(fs_info, &ei->io_failure_tree,
> -			    IO_TREE_INODE_IO_FAILURE, inode);
>   	extent_io_tree_init(fs_info, &ei->file_extent_tree,
>   			    IO_TREE_INODE_FILE_EXTENT, inode);
>   	ei->io_tree.track_uptodate = true;
> -	ei->io_failure_tree.track_uptodate = true;
>   	atomic_set(&ei->sync_writers, 0);
>   	mutex_init(&ei->log_mutex);
>   	btrfs_ordered_inode_tree_init(&ei->ordered_tree);
> @@ -10370,7 +10192,6 @@ struct btrfs_encoded_read_private {
>   	wait_queue_head_t wait;
>   	atomic_t pending;
>   	blk_status_t status;
> -	bool skip_csum;
>   };
>
>   static blk_status_t submit_encoded_read_bio(struct btrfs_inode *inode,
> @@ -10378,57 +10199,17 @@ static blk_status_t submit_encoded_read_bio(struct btrfs_inode *inode,
>   {
>   	struct btrfs_encoded_read_private *priv = btrfs_bio(bio)->private;
>   	struct btrfs_fs_info *fs_info = inode->root->fs_info;
> -	blk_status_t ret;
> -
> -	if (!priv->skip_csum) {
> -		ret = btrfs_lookup_bio_sums(&inode->vfs_inode, bio, NULL);
> -		if (ret)
> -			return ret;
> -	}
>
>   	atomic_inc(&priv->pending);
>   	btrfs_submit_bio(fs_info, bio, mirror_num);
>   	return BLK_STS_OK;
>   }
>
> -static blk_status_t btrfs_encoded_read_verify_csum(struct btrfs_bio *bbio)
> -{
> -	const bool uptodate = (bbio->bio.bi_status == BLK_STS_OK);
> -	struct btrfs_encoded_read_private *priv = bbio->private;
> -	struct btrfs_inode *inode = priv->inode;
> -	struct btrfs_fs_info *fs_info = inode->root->fs_info;
> -	u32 sectorsize = fs_info->sectorsize;
> -	struct bio_vec *bvec;
> -	struct bvec_iter_all iter_all;
> -	u32 bio_offset = 0;
> -
> -	if (priv->skip_csum || !uptodate)
> -		return bbio->bio.bi_status;
> -
> -	bio_for_each_segment_all(bvec, &bbio->bio, iter_all) {
> -		unsigned int i, nr_sectors, pgoff;
> -
> -		nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec->bv_len);
> -		pgoff = bvec->bv_offset;
> -		for (i = 0; i < nr_sectors; i++) {
> -			ASSERT(pgoff < PAGE_SIZE);
> -			if (btrfs_check_data_csum(&inode->vfs_inode, bbio, bio_offset,
> -					    bvec->bv_page, pgoff))
> -				return BLK_STS_IOERR;
> -			bio_offset += sectorsize;
> -			pgoff += sectorsize;
> -		}
> -	}
> -	return BLK_STS_OK;
> -}
> -
>   static void btrfs_encoded_read_endio(struct btrfs_bio *bbio)
>   {
>   	struct btrfs_encoded_read_private *priv = bbio->private;
> -	blk_status_t status;
>
> -	status = btrfs_encoded_read_verify_csum(bbio);
> -	if (status) {
> +	if (bbio->bio.bi_status) {
>   		/*
>   		 * The memory barrier implied by the atomic_dec_return() here
>   		 * pairs with the memory barrier implied by the
> @@ -10437,11 +10218,10 @@ static void btrfs_encoded_read_endio(struct btrfs_bio *bbio)
>   		 * write is observed before the load of status in
>   		 * btrfs_encoded_read_regular_fill_pages().
>   		 */
> -		WRITE_ONCE(priv->status, status);
> +		WRITE_ONCE(priv->status, bbio->bio.bi_status);
>   	}
>   	if (!atomic_dec_return(&priv->pending))
>   		wake_up(&priv->wait);
> -	btrfs_bio_free_csum(bbio);
>   	bio_put(&bbio->bio);
>   }
>
> @@ -10454,7 +10234,6 @@ int btrfs_encoded_read_regular_fill_pages(struct btrfs_inode *inode,
>   		.inode = inode,
>   		.file_offset = file_offset,
>   		.pending = ATOMIC_INIT(1),
> -		.skip_csum = (inode->flags & BTRFS_INODE_NODATASUM),
>   	};
>   	unsigned long i = 0;
>   	u64 cur = 0;
> @@ -10490,6 +10269,7 @@ int btrfs_encoded_read_regular_fill_pages(struct btrfs_inode *inode,
>
>   			if (!bio) {
>   				bio = btrfs_bio_alloc(BIO_MAX_VECS, REQ_OP_READ,
> +						      &inode->vfs_inode,
>   						      btrfs_encoded_read_endio,
>   						      &priv);
>   				bio->bi_iter.bi_sector =
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index dff735e36da96..b8472ab466abe 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -35,6 +35,14 @@
>   #include "zoned.h"
>
>   static struct bio_set btrfs_bioset;
> +static struct bio_set btrfs_repair_bioset;
> +static mempool_t btrfs_failed_bio_pool;
> +
> +struct btrfs_failed_bio {
> +	struct btrfs_bio *bbio;
> +	int num_copies;
> +	atomic_t repair_count;
> +};
>
>   #define BTRFS_BLOCK_GROUP_STRIPE_MASK	(BTRFS_BLOCK_GROUP_RAID0 | \
>   					 BTRFS_BLOCK_GROUP_RAID10 | \
> @@ -6646,10 +6654,11 @@ int btrfs_map_sblock(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
>    * Initialize a btrfs_bio structure.  This skips the embedded bio itself as it
>    * is already initialized by the block layer.
>    */
> -static inline void btrfs_bio_init(struct btrfs_bio *bbio,
> -				  btrfs_bio_end_io_t end_io, void *private)
> +static void btrfs_bio_init(struct btrfs_bio *bbio, struct inode *inode,
> +			   btrfs_bio_end_io_t end_io, void *private)
>   {
>   	memset(bbio, 0, offsetof(struct btrfs_bio, bio));
> +	bbio->inode = inode;
>   	bbio->end_io = end_io;
>   	bbio->private = private;
>   }
> @@ -6662,16 +6671,18 @@ static inline void btrfs_bio_init(struct btrfs_bio *bbio,
>    * a mempool.
>    */
>   struct bio *btrfs_bio_alloc(unsigned int nr_vecs, blk_opf_t opf,
> -			    btrfs_bio_end_io_t end_io, void *private)
> +			    struct inode *inode, btrfs_bio_end_io_t end_io,
> +			    void *private)
>   {
>   	struct bio *bio;
>
>   	bio = bio_alloc_bioset(NULL, nr_vecs, opf, GFP_NOFS, &btrfs_bioset);
> -	btrfs_bio_init(btrfs_bio(bio), end_io, private);
> +	btrfs_bio_init(btrfs_bio(bio), inode, end_io, private);
>   	return bio;
>   }
>
>   struct bio *btrfs_bio_clone_partial(struct bio *orig, u64 offset, u64 size,
> +				    struct inode *inode,
>   				    btrfs_bio_end_io_t end_io, void *private)
>   {
>   	struct bio *bio;
> @@ -6681,13 +6692,174 @@ struct bio *btrfs_bio_clone_partial(struct bio *orig, u64 offset, u64 size,
>
>   	bio = bio_alloc_clone(orig->bi_bdev, orig, GFP_NOFS, &btrfs_bioset);
>   	bbio = btrfs_bio(bio);
> -	btrfs_bio_init(bbio, end_io, private);
> +	btrfs_bio_init(bbio, inode, end_io, private);
>
>   	bio_trim(bio, offset >> 9, size >> 9);
> -	bbio->iter = bio->bi_iter;
>   	return bio;
>   }
>
> +static int next_repair_mirror(struct btrfs_failed_bio *fbio, int cur_mirror)
> +{
> +	if (cur_mirror == fbio->num_copies)
> +		return cur_mirror + 1 - fbio->num_copies;
> +	return cur_mirror + 1;
> +}
> +
> +static int prev_repair_mirror(struct btrfs_failed_bio *fbio, int cur_mirror)
> +{
> +	if (cur_mirror == 1)
> +		return fbio->num_copies;
> +	return cur_mirror - 1;
> +}
> +
> +static void btrfs_repair_done(struct btrfs_failed_bio *fbio)
> +{
> +	if (atomic_dec_and_test(&fbio->repair_count)) {
> +		fbio->bbio->end_io(fbio->bbio);
> +		mempool_free(fbio, &btrfs_failed_bio_pool);
> +	}
> +}
> +
> +static void btrfs_end_repair_bio(struct btrfs_bio *repair_bbio,
> +				 struct btrfs_device *dev)
> +{
> +	struct btrfs_failed_bio *fbio = repair_bbio->private;
> +	struct inode *inode = repair_bbio->inode;
> +	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> +	struct bio_vec *bv = bio_first_bvec_all(&repair_bbio->bio);
> +	int mirror = repair_bbio->mirror_num;
> +
> +	if (repair_bbio->bio.bi_status ||
> +	    !btrfs_data_csum_ok(repair_bbio, dev, 0, bv)) {
> +		bio_reset(&repair_bbio->bio, NULL, REQ_OP_READ);
> +		repair_bbio->bio.bi_iter = repair_bbio->saved_iter;
> +
> +		mirror = next_repair_mirror(fbio, mirror);
> +		if (mirror == fbio->bbio->mirror_num) {
> +			btrfs_debug(fs_info, "no mirror left");
> +			fbio->bbio->bio.bi_status = BLK_STS_IOERR;
> +			goto done;
> +		}
> +
> +		btrfs_submit_bio(fs_info, &repair_bbio->bio, mirror);
> +		return;
> +	}
> +
> +	do {
> +		mirror = prev_repair_mirror(fbio, mirror);
> +		btrfs_repair_io_failure(fs_info, btrfs_ino(BTRFS_I(inode)),
> +				  repair_bbio->file_offset, fs_info->sectorsize,
> +				  repair_bbio->saved_iter.bi_sector <<
> +					SECTOR_SHIFT,
> +				  bv->bv_page, bv->bv_offset, mirror);
> +	} while (mirror != fbio->bbio->mirror_num);
> +
> +done:
> +	btrfs_repair_done(fbio);
> +	bio_put(&repair_bbio->bio);
> +}
> +
> +/*
> + * Try to kick off a repair read to the next available mirror for a bad
> + * sector.
> + *
> + * This primarily tries to recover good data to serve the actual read request,
> + * but also tries to write the good data back to the bad mirror(s) when a
> + * read succeeded to restore the redundancy.
> + */
> +static void repair_one_sector(struct btrfs_bio *failed_bbio, u32 bio_offset,
> +			      struct bio_vec *bv,
> +			      struct btrfs_failed_bio **fbio)
> +{
> +	struct inode *inode = failed_bbio->inode;
> +	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> +	const u32 sectorsize = fs_info->sectorsize;
> +	const u64 logical = failed_bbio->saved_iter.bi_sector << SECTOR_SHIFT;
> +	struct btrfs_bio *repair_bbio;
> +	struct bio *repair_bio;
> +	int num_copies;
> +	int mirror;
> +
> +	btrfs_debug(fs_info, "repair read error: read error at %llu",
> +		    failed_bbio->file_offset + bio_offset);
> +
> +	num_copies = btrfs_num_copies(fs_info, logical, sectorsize);
> +	if (num_copies == 1) {
> +		btrfs_debug(fs_info, "no copy to repair from");
> +		failed_bbio->bio.bi_status = BLK_STS_IOERR;
> +		return;
> +	}
> +
> +	if (!*fbio) {
> +		*fbio = mempool_alloc(&btrfs_failed_bio_pool, GFP_NOFS);
> +		(*fbio)->bbio = failed_bbio;
> +		(*fbio)->num_copies = num_copies;
> +		atomic_set(&(*fbio)->repair_count, 1);
> +	}
> +
> +	atomic_inc(&(*fbio)->repair_count);
> +
> +	repair_bio = bio_alloc_bioset(NULL, 1, REQ_OP_READ, GFP_NOFS,
> +				      &btrfs_repair_bioset);
> +	repair_bio->bi_iter.bi_sector = failed_bbio->saved_iter.bi_sector;
> +	bio_add_page(repair_bio, bv->bv_page, bv->bv_len, bv->bv_offset);
> +
> +	repair_bbio = btrfs_bio(repair_bio);
> +	btrfs_bio_init(repair_bbio, failed_bbio->inode, NULL, *fbio);
> +	repair_bbio->file_offset = failed_bbio->file_offset + bio_offset;
> +
> +	mirror = next_repair_mirror(*fbio, failed_bbio->mirror_num);
> +	btrfs_debug(fs_info, "submitting repair read to mirror %d", mirror);
> +	btrfs_submit_bio(fs_info, repair_bio, mirror);
> +}
> +
> +static void btrfs_check_read_bio(struct btrfs_bio *bbio,
> +				 struct btrfs_device *dev)
> +{
> +	struct inode *inode = bbio->inode;
> +	struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
> +	unsigned int sectorsize = fs_info->sectorsize;
> +	struct bvec_iter *iter = &bbio->saved_iter;
> +	blk_status_t status = bbio->bio.bi_status;
> +	struct btrfs_failed_bio *fbio = NULL;
> +	u32 offset = 0;
> +
> +	/*
> +	 * Hand off repair bios to the repair code as there is no upper level
> +	 * submitter for them.
> +	 */
> +	if (unlikely(bbio->bio.bi_pool == &btrfs_repair_bioset)) {
> +		btrfs_end_repair_bio(bbio, dev);
> +		return;
> +	}
> +
> +	/* Metadata reads are checked and repaired by the submitter */
> +	if (bbio->bio.bi_opf & REQ_META)
> +		goto done;
> +
> +	/* Clear the I/O error.  A failed repair will reset it */
> +	bbio->bio.bi_status = BLK_STS_OK;
> +
> +	while (iter->bi_size) {
> +		struct bio_vec bv = bio_iter_iovec(&bbio->bio, *iter);
> +
> +		bv.bv_len = min(bv.bv_len, sectorsize);
> +		if (status || !btrfs_data_csum_ok(bbio, dev, offset, &bv))
> +			repair_one_sector(bbio, offset, &bv, &fbio);
> +
> +	     	bio_advance_iter_single(&bbio->bio, iter, sectorsize);
> +		offset += sectorsize;
> +	}
> +
> +	if (bbio->csum != bbio->csum_inline)
> +		kfree(bbio->csum);
> +done:
> +	if (unlikely(fbio))
> +		btrfs_repair_done(fbio);
> +	else
> +		bbio->end_io(bbio);
> +}
> +
>   static void btrfs_log_dev_io_error(struct bio *bio, struct btrfs_device *dev)
>   {
>   	if (!dev || !dev->bdev)
> @@ -6716,18 +6888,19 @@ static void btrfs_end_bio_work(struct work_struct *work)
>   	struct btrfs_bio *bbio =
>   		container_of(work, struct btrfs_bio, end_io_work);
>
> -	bbio->end_io(bbio);
> +	btrfs_check_read_bio(bbio, bbio->bio.bi_private);
>   }
>
>   static void btrfs_simple_end_io(struct bio *bio)
>   {
> -	struct btrfs_fs_info *fs_info = bio->bi_private;
>   	struct btrfs_bio *bbio = btrfs_bio(bio);
> +	struct btrfs_device *dev = bio->bi_private;
> +	struct btrfs_fs_info *fs_info = btrfs_sb(bbio->inode->i_sb);
>
>   	btrfs_bio_counter_dec(fs_info);
>
>   	if (bio->bi_status)
> -		btrfs_log_dev_io_error(bio, bbio->device);
> +		btrfs_log_dev_io_error(bio, dev);
>
>   	if (bio_op(bio) == REQ_OP_READ) {
>   		INIT_WORK(&bbio->end_io_work, btrfs_end_bio_work);
> @@ -6744,7 +6917,10 @@ static void btrfs_raid56_end_io(struct bio *bio)
>
>   	btrfs_bio_counter_dec(bioc->fs_info);
>   	bbio->mirror_num = bioc->mirror_num;
> -	bbio->end_io(bbio);
> +	if (bio_op(bio) == REQ_OP_READ)
> +		btrfs_check_read_bio(bbio, NULL);
> +	else
> +		bbio->end_io(bbio);
>
>   	btrfs_put_bioc(bioc);
>   }
> @@ -6852,6 +7028,7 @@ static void btrfs_submit_mirrored_bio(struct btrfs_io_context *bioc, int dev_nr)
>
>   void btrfs_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio, int mirror_num)
>   {
> +	struct btrfs_bio *bbio = btrfs_bio(bio);
>   	u64 logical = bio->bi_iter.bi_sector << 9;
>   	u64 length = bio->bi_iter.bi_size;
>   	u64 map_length = length;
> @@ -6862,11 +7039,8 @@ void btrfs_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio, int mirror
>   	btrfs_bio_counter_inc_blocked(fs_info);
>   	ret = __btrfs_map_block(fs_info, btrfs_op(bio), logical, &map_length,
>   				&bioc, &smap, &mirror_num, 1);
> -	if (ret) {
> -		btrfs_bio_counter_dec(fs_info);
> -		btrfs_bio_end_io(btrfs_bio(bio), errno_to_blk_status(ret));
> -		return;
> -	}
> +	if (ret)
> +		goto fail;
>
>   	if (map_length < length) {
>   		btrfs_crit(fs_info,
> @@ -6875,12 +7049,22 @@ void btrfs_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio, int mirror
>   		BUG();
>   	}
>
> +	/*
> +	 * Save the iter for the end_io handler and preload the checksums for
> +	 * data reads.
> +	 */
> +	if (bio_op(bio) == REQ_OP_READ && !(bio->bi_opf & REQ_META)) {
> +		bbio->saved_iter = bio->bi_iter;
> +		ret = btrfs_lookup_bio_sums(bbio);
> +		if (ret)
> +			goto fail;
> +	}
> +
>   	if (!bioc) {
>   		/* Single mirror read/write fast path */
>   		btrfs_bio(bio)->mirror_num = mirror_num;
> -		btrfs_bio(bio)->device = smap.dev;
>   		bio->bi_iter.bi_sector = smap.physical >> SECTOR_SHIFT;
> -		bio->bi_private = fs_info;
> +		bio->bi_private = smap.dev;
>   		bio->bi_end_io = btrfs_simple_end_io;
>   		btrfs_submit_dev_bio(smap.dev, bio);
>   	} else if (bioc->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
> @@ -6900,6 +7084,11 @@ void btrfs_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio, int mirror
>   		for (dev_nr = 0; dev_nr < total_devs; dev_nr++)
>   			btrfs_submit_mirrored_bio(bioc, dev_nr);
>   	}
> +
> +	return;
> +fail:
> +	btrfs_bio_counter_dec(fs_info);
> +	btrfs_bio_end_io(bbio, errno_to_blk_status(ret));
>   }
>
>   /*
> @@ -8499,10 +8688,25 @@ int __init btrfs_bioset_init(void)
>   			offsetof(struct btrfs_bio, bio),
>   			BIOSET_NEED_BVECS))
>   		return -ENOMEM;
> +	if (bioset_init(&btrfs_repair_bioset, BIO_POOL_SIZE,
> +			offsetof(struct btrfs_bio, bio),
> +			BIOSET_NEED_BVECS))
> +		goto out_free_bioset;
> +	if (mempool_init_kmalloc_pool(&btrfs_failed_bio_pool, BIO_POOL_SIZE,
> +				      sizeof(struct btrfs_failed_bio)))
> +		goto out_free_repair_bioset;
>   	return 0;
> +
> +out_free_repair_bioset:
> +	bioset_exit(&btrfs_repair_bioset);
> +out_free_bioset:
> +	bioset_exit(&btrfs_bioset);
> +	return -ENOMEM;
>   }
>
>   void __cold btrfs_bioset_exit(void)
>   {
> +	mempool_exit(&btrfs_failed_bio_pool);
> +	bioset_exit(&btrfs_repair_bioset);
>   	bioset_exit(&btrfs_bioset);
>   }
> diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
> index b368356fa78a1..58c4156caa736 100644
> --- a/fs/btrfs/volumes.h
> +++ b/fs/btrfs/volumes.h
> @@ -364,27 +364,28 @@ struct btrfs_fs_devices {
>   typedef void (*btrfs_bio_end_io_t)(struct btrfs_bio *bbio);
>
>   /*
> - * Additional info to pass along bio.
> - *
> - * Mostly for btrfs specific features like csum and mirror_num.
> + * Highlevel btrfs I/O structure.  It is allocated by btrfs_bio_alloc and
> + * passed to btrfs_submit_bio for mapping to the physical devices.
>    */
>   struct btrfs_bio {
> -	unsigned int mirror_num;
> -
> -	/* for direct I/O */
> +	/* Inode and offset into it that this I/O operates on. */
> +	struct inode *inode;
>   	u64 file_offset;
>
> -	/* @device is for stripe IO submission. */
> -	struct btrfs_device *device;
> +	/*
> +	 * Checksumming and original I/O information for internal use in the
> +	 * btrfs_submit_bio machinery.
> +	 */
>   	u8 *csum;
>   	u8 csum_inline[BTRFS_BIO_INLINE_CSUM_SIZE];
> -	struct bvec_iter iter;
> +	struct bvec_iter saved_iter;
>
>   	/* End I/O information supplied to btrfs_bio_alloc */
>   	btrfs_bio_end_io_t end_io;
>   	void *private;
>
> -	/* For read end I/O handling */
> +	/* For internal use in read end I/O handling */
> +	unsigned int mirror_num;
>   	struct work_struct end_io_work;
>
>   	/*
> @@ -403,8 +404,10 @@ int __init btrfs_bioset_init(void);
>   void __cold btrfs_bioset_exit(void);
>
>   struct bio *btrfs_bio_alloc(unsigned int nr_vecs, blk_opf_t opf,
> -			    btrfs_bio_end_io_t end_io, void *private);
> +			    struct inode *inode, btrfs_bio_end_io_t end_io,
> +			    void *private);
>   struct bio *btrfs_bio_clone_partial(struct bio *orig, u64 offset, u64 size,
> +				    struct inode *inode,
>   				    btrfs_bio_end_io_t end_io, void *private);
>
>   static inline void btrfs_bio_end_io(struct btrfs_bio *bbio, blk_status_t status)
> @@ -413,30 +416,6 @@ static inline void btrfs_bio_end_io(struct btrfs_bio *bbio, blk_status_t status)
>   	bbio->end_io(bbio);
>   }
>
> -static inline void btrfs_bio_free_csum(struct btrfs_bio *bbio)
> -{
> -	if (bbio->csum != bbio->csum_inline) {
> -		kfree(bbio->csum);
> -		bbio->csum = NULL;
> -	}
> -}
> -
> -/*
> - * Iterate through a btrfs_bio (@bbio) on a per-sector basis.
> - *
> - * bvl        - struct bio_vec
> - * bbio       - struct btrfs_bio
> - * iters      - struct bvec_iter
> - * bio_offset - unsigned int
> - */
> -#define btrfs_bio_for_each_sector(fs_info, bvl, bbio, iter, bio_offset)	\
> -	for ((iter) = (bbio)->iter, (bio_offset) = 0;			\
> -	     (iter).bi_size &&					\
> -	     (((bvl) = bio_iter_iovec((&(bbio)->bio), (iter))), 1);	\
> -	     (bio_offset) += fs_info->sectorsize,			\
> -	     bio_advance_iter_single(&(bbio)->bio, &(iter),		\
> -	     (fs_info)->sectorsize))
> -
>   struct btrfs_io_stripe {
>   	struct btrfs_device *dev;
>   	union {
> diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h
> index f8a4118b16574..ed50e81174bf4 100644
> --- a/include/trace/events/btrfs.h
> +++ b/include/trace/events/btrfs.h
> @@ -84,7 +84,6 @@ struct raid56_bio_trace_info;
>   	EM( IO_TREE_FS_EXCLUDED_EXTENTS,  "EXCLUDED_EXTENTS")	    \
>   	EM( IO_TREE_BTREE_INODE_IO,	  "BTREE_INODE_IO")	    \
>   	EM( IO_TREE_INODE_IO,		  "INODE_IO")		    \
> -	EM( IO_TREE_INODE_IO_FAILURE,	  "INODE_IO_FAILURE")	    \
>   	EM( IO_TREE_RELOC_BLOCKS,	  "RELOC_BLOCKS")	    \
>   	EM( IO_TREE_TRANS_DIRTY_PAGES,	  "TRANS_DIRTY_PAGES")      \
>   	EM( IO_TREE_ROOT_DIRTY_LOG_PAGES, "ROOT_DIRTY_LOG_PAGES")   \