move the low-level btrfs_bio code into a separate file v3

move the low-level btrfs_bio code into a separate file v3

[Christoph Hellwig]

Hi all,

this small series creates a new bio.c file (and a bio.h header for it)
to contain all the "storage" layer code below btrfs_submit_bio.  The
amount of code sitting below btrfs_submit_bio will grow a lot with
the "consolidate btrfs checksumming, repair and bio splitting" series,
so this pure code move series triest to prepare for that by making
sure we have a neat file to add it to.

Changes since v2:
 - rebased against the rcu_string changes in misc-next

Changes since v1:
 - rebased to the latest misc-next branch
 - added a new patch to move struct btrfs_tree_parent_check into a new
   header to invoide include hell

[PATCH 1/3] btrfs: move struct btrfs_tree_parent_check out of disk-io.h

[Christoph Hellwig]

Move struct btrfs_tree_parent_check out of disk-io.h so that volumes.h
an various .c files don't have to include disk-io.h just for it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
---
 fs/btrfs/backref.c      |  1 +
 fs/btrfs/disk-io.h      | 30 +-----------------------------
 fs/btrfs/parent-check.h | 36 ++++++++++++++++++++++++++++++++++++
 fs/btrfs/print-tree.c   |  1 +
 fs/btrfs/qgroup.c       |  1 +
 fs/btrfs/tree-mod-log.c |  1 +
 fs/btrfs/volumes.h      |  2 +-
 7 files changed, 42 insertions(+), 30 deletions(-)
 create mode 100644 fs/btrfs/parent-check.h

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 55c072ba67471..9496aa93a8dcc 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -19,6 +19,7 @@
 #include "accessors.h"
 #include "extent-tree.h"
 #include "relocation.h"
+#include "parent-check.h"
 
 /* Just arbitrary numbers so we can be sure one of these happened. */
 #define BACKREF_FOUND_SHARED     6
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index 03fe4154ffb83..363935cfc0844 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -25,37 +25,9 @@ static inline u64 btrfs_sb_offset(int mirror)
 	return BTRFS_SUPER_INFO_OFFSET;
 }
 
-/* All the extra info needed to verify the parentness of a tree block. */
-struct btrfs_tree_parent_check {
-	/*
-	 * The owner check against the tree block.
-	 *
-	 * Can be 0 to skip the owner check.
-	 */
-	u64 owner_root;
-
-	/*
-	 * Expected transid, can be 0 to skip the check, but such skip
-	 * should only be utlized for backref walk related code.
-	 */
-	u64 transid;
-
-	/*
-	 * The expected first key.
-	 *
-	 * This check can be skipped if @has_first_key is false, such skip
-	 * can happen for case where we don't have the parent node key,
-	 * e.g. reading the tree root, doing backref walk.
-	 */
-	struct btrfs_key first_key;
-	bool has_first_key;
-
-	/* The expected level. Should always be set. */
-	u8 level;
-};
-
 struct btrfs_device;
 struct btrfs_fs_devices;
+struct btrfs_tree_parent_check;
 
 void btrfs_check_leaked_roots(struct btrfs_fs_info *fs_info);
 void btrfs_init_fs_info(struct btrfs_fs_info *fs_info);
diff --git a/fs/btrfs/parent-check.h b/fs/btrfs/parent-check.h
new file mode 100644
index 0000000000000..333f23ea28e25
--- /dev/null
+++ b/fs/btrfs/parent-check.h
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef BTRFS_PARENT_CHECK_H
+#define BTRFS_PARENT_CHECK_H
+
+#include <uapi/linux/btrfs_tree.h>
+
+/* All the extra info needed to verify the parentness of a tree block. */
+struct btrfs_tree_parent_check {
+	/*
+	 * The owner check against the tree block.
+	 *
+	 * Can be 0 to skip the owner check.
+	 */
+	u64 owner_root;
+
+	/*
+	 * Expected transid, can be 0 to skip the check, but such skip
+	 * should only be utlized for backref walk related code.
+	 */
+	u64 transid;
+
+	/*
+	 * The expected first key.
+	 *
+	 * This check can be skipped if @has_first_key is false, such skip
+	 * can happen for case where we don't have the parent node key,
+	 * e.g. reading the tree root, doing backref walk.
+	 */
+	struct btrfs_key first_key;
+	bool has_first_key;
+
+	/* The expected level. Should always be set. */
+	u8 level;
+};
+
+#endif /* BTRFS_PARENT_CHECK_H */
diff --git a/fs/btrfs/print-tree.c b/fs/btrfs/print-tree.c
index 1469aa55ad482..00d5da5f3c333 100644
--- a/fs/btrfs/print-tree.c
+++ b/fs/btrfs/print-tree.c
@@ -8,6 +8,7 @@
 #include "disk-io.h"
 #include "print-tree.h"
 #include "accessors.h"
+#include "parent-check.h"
 
 struct root_name_map {
 	u64 id;
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 05e79f7b4433a..365482ad0421b 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -28,6 +28,7 @@
 #include "accessors.h"
 #include "extent-tree.h"
 #include "root-tree.h"
+#include "parent-check.h"
 
 /*
  * Helpers to access qgroup reservation
diff --git a/fs/btrfs/tree-mod-log.c b/fs/btrfs/tree-mod-log.c
index 779ad44d285f8..5b91a2a88a398 100644
--- a/fs/btrfs/tree-mod-log.c
+++ b/fs/btrfs/tree-mod-log.c
@@ -5,6 +5,7 @@
 #include "disk-io.h"
 #include "fs.h"
 #include "accessors.h"
+#include "parent-check.h"
 
 struct tree_mod_root {
 	u64 logical;
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 2c90e50c460a3..7467df319d3b2 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -11,7 +11,7 @@
 #include <linux/btrfs.h>
 #include "async-thread.h"
 #include "messages.h"
-#include "disk-io.h"
+#include "parent-check.h"
 #include "rcu-string.h"
 
 #define BTRFS_MAX_DATA_CHUNK_SIZE	(10ULL * SZ_1G)
-- 
2.30.2

[PATCH 2/3] btrfs: split the bio submission path into a separate file

[Christoph Hellwig]

The code used by btrfs_submit_bio only interacts with the rest of
volumes.c through __btrfs_map_block (which itself is a more generic
version of two exported helpers) and does not really have anything
to do with volumes.c.  Create a new bio.c file and a bio.h header
going along with it for the btrfs_bio-based storage layer, which
will grow even more going forward.

Also update the file with my copyright notice given that a large
part of the moved code was written or rewritten by me.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
 fs/btrfs/Makefile      |   2 +-
 fs/btrfs/bio.c         | 291 ++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/bio.h         | 126 ++++++++++++++++++
 fs/btrfs/compression.c |   2 +-
 fs/btrfs/ctree.c       |   1 +
 fs/btrfs/disk-io.c     |   2 +-
 fs/btrfs/extent-tree.c |   1 +
 fs/btrfs/extent_io.c   |   2 +-
 fs/btrfs/file-item.c   |   2 +-
 fs/btrfs/inode.c       |   2 +-
 fs/btrfs/relocation.c  |   1 +
 fs/btrfs/super.c       |   2 +-
 fs/btrfs/tree-log.c    |   1 +
 fs/btrfs/volumes.c     | 296 +----------------------------------------
 fs/btrfs/volumes.h     | 111 +---------------
 15 files changed, 438 insertions(+), 404 deletions(-)
 create mode 100644 fs/btrfs/bio.c
 create mode 100644 fs/btrfs/bio.h

diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
index 84fb3b4c35b07..555c962fdad66 100644
--- a/fs/btrfs/Makefile
+++ b/fs/btrfs/Makefile
@@ -31,7 +31,7 @@ btrfs-y += super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
 	   backref.o ulist.o qgroup.o send.o dev-replace.o raid56.o \
 	   uuid-tree.o props.o free-space-tree.o tree-checker.o space-info.o \
 	   block-rsv.o delalloc-space.o block-group.o discard.o reflink.o \
-	   subpage.o tree-mod-log.o extent-io-tree.o fs.o messages.o
+	   subpage.o tree-mod-log.o extent-io-tree.o fs.o messages.o bio.o
 
 btrfs-$(CONFIG_BTRFS_FS_POSIX_ACL) += acl.o
 btrfs-$(CONFIG_BTRFS_FS_CHECK_INTEGRITY) += check-integrity.o
diff --git a/fs/btrfs/bio.c b/fs/btrfs/bio.c
new file mode 100644
index 0000000000000..194b927ef9ee4
--- /dev/null
+++ b/fs/btrfs/bio.c
@@ -0,0 +1,291 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2007 Oracle.  All rights reserved.
+ * Copyright (C) 2022 Christoph Hellwig.
+ */
+#include <linux/bio.h>
+#include "bio.h"
+#include "ctree.h"
+#include "volumes.h"
+#include "raid56.h"
+#include "async-thread.h"
+#include "check-integrity.h"
+#include "dev-replace.h"
+#include "rcu-string.h"
+#include "zoned.h"
+
+static struct bio_set btrfs_bioset;
+
+/*
+ * 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)
+{
+	memset(bbio, 0, offsetof(struct btrfs_bio, bio));
+	bbio->end_io = end_io;
+	bbio->private = private;
+}
+
+/*
+ * Allocate a btrfs_bio structure.  The btrfs_bio is the main I/O container for
+ * btrfs, and is used for all I/O submitted through btrfs_submit_bio.
+ *
+ * Just like the underlying bio_alloc_bioset it will not fail as it is backed by
+ * 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 bio *bio;
+
+	bio = bio_alloc_bioset(NULL, nr_vecs, opf, GFP_NOFS, &btrfs_bioset);
+	btrfs_bio_init(btrfs_bio(bio), end_io, private);
+	return bio;
+}
+
+struct bio *btrfs_bio_clone_partial(struct bio *orig, u64 offset, u64 size,
+				    btrfs_bio_end_io_t end_io, void *private)
+{
+	struct bio *bio;
+	struct btrfs_bio *bbio;
+
+	ASSERT(offset <= UINT_MAX && size <= UINT_MAX);
+
+	bio = bio_alloc_clone(orig->bi_bdev, orig, GFP_NOFS, &btrfs_bioset);
+	bbio = btrfs_bio(bio);
+	btrfs_bio_init(bbio, end_io, private);
+
+	bio_trim(bio, offset >> 9, size >> 9);
+	bbio->iter = bio->bi_iter;
+	return bio;
+}
+
+static void btrfs_log_dev_io_error(struct bio *bio, struct btrfs_device *dev)
+{
+	if (!dev || !dev->bdev)
+		return;
+	if (bio->bi_status != BLK_STS_IOERR && bio->bi_status != BLK_STS_TARGET)
+		return;
+
+	if (btrfs_op(bio) == BTRFS_MAP_WRITE)
+		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
+	if (!(bio->bi_opf & REQ_RAHEAD))
+		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
+	if (bio->bi_opf & REQ_PREFLUSH)
+		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_FLUSH_ERRS);
+}
+
+static struct workqueue_struct *btrfs_end_io_wq(struct btrfs_fs_info *fs_info,
+						struct bio *bio)
+{
+	if (bio->bi_opf & REQ_META)
+		return fs_info->endio_meta_workers;
+	return fs_info->endio_workers;
+}
+
+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);
+}
+
+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);
+
+	btrfs_bio_counter_dec(fs_info);
+
+	if (bio->bi_status)
+		btrfs_log_dev_io_error(bio, bbio->device);
+
+	if (bio_op(bio) == REQ_OP_READ) {
+		INIT_WORK(&bbio->end_io_work, btrfs_end_bio_work);
+		queue_work(btrfs_end_io_wq(fs_info, bio), &bbio->end_io_work);
+	} else {
+		bbio->end_io(bbio);
+	}
+}
+
+static void btrfs_raid56_end_io(struct bio *bio)
+{
+	struct btrfs_io_context *bioc = bio->bi_private;
+	struct btrfs_bio *bbio = btrfs_bio(bio);
+
+	btrfs_bio_counter_dec(bioc->fs_info);
+	bbio->mirror_num = bioc->mirror_num;
+	bbio->end_io(bbio);
+
+	btrfs_put_bioc(bioc);
+}
+
+static void btrfs_orig_write_end_io(struct bio *bio)
+{
+	struct btrfs_io_stripe *stripe = bio->bi_private;
+	struct btrfs_io_context *bioc = stripe->bioc;
+	struct btrfs_bio *bbio = btrfs_bio(bio);
+
+	btrfs_bio_counter_dec(bioc->fs_info);
+
+	if (bio->bi_status) {
+		atomic_inc(&bioc->error);
+		btrfs_log_dev_io_error(bio, stripe->dev);
+	}
+
+	/*
+	 * Only send an error to the higher layers if it is beyond the tolerance
+	 * threshold.
+	 */
+	if (atomic_read(&bioc->error) > bioc->max_errors)
+		bio->bi_status = BLK_STS_IOERR;
+	else
+		bio->bi_status = BLK_STS_OK;
+
+	bbio->end_io(bbio);
+	btrfs_put_bioc(bioc);
+}
+
+static void btrfs_clone_write_end_io(struct bio *bio)
+{
+	struct btrfs_io_stripe *stripe = bio->bi_private;
+
+	if (bio->bi_status) {
+		atomic_inc(&stripe->bioc->error);
+		btrfs_log_dev_io_error(bio, stripe->dev);
+	}
+
+	/* Pass on control to the original bio this one was cloned from */
+	bio_endio(stripe->bioc->orig_bio);
+	bio_put(bio);
+}
+
+static void btrfs_submit_dev_bio(struct btrfs_device *dev, struct bio *bio)
+{
+	if (!dev || !dev->bdev ||
+	    test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state) ||
+	    (btrfs_op(bio) == BTRFS_MAP_WRITE &&
+	     !test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state))) {
+		bio_io_error(bio);
+		return;
+	}
+
+	bio_set_dev(bio, dev->bdev);
+
+	/*
+	 * For zone append writing, bi_sector must point the beginning of the
+	 * zone
+	 */
+	if (bio_op(bio) == REQ_OP_ZONE_APPEND) {
+		u64 physical = bio->bi_iter.bi_sector << SECTOR_SHIFT;
+
+		if (btrfs_dev_is_sequential(dev, physical)) {
+			u64 zone_start = round_down(physical,
+						    dev->fs_info->zone_size);
+
+			bio->bi_iter.bi_sector = zone_start >> SECTOR_SHIFT;
+		} else {
+			bio->bi_opf &= ~REQ_OP_ZONE_APPEND;
+			bio->bi_opf |= REQ_OP_WRITE;
+		}
+	}
+	btrfs_debug_in_rcu(dev->fs_info,
+	"%s: rw %d 0x%x, sector=%llu, dev=%lu (%s id %llu), size=%u",
+		__func__, bio_op(bio), bio->bi_opf, bio->bi_iter.bi_sector,
+		(unsigned long)dev->bdev->bd_dev, btrfs_dev_name(dev),
+		dev->devid, bio->bi_iter.bi_size);
+
+	btrfsic_check_bio(bio);
+	submit_bio(bio);
+}
+
+static void btrfs_submit_mirrored_bio(struct btrfs_io_context *bioc, int dev_nr)
+{
+	struct bio *orig_bio = bioc->orig_bio, *bio;
+
+	ASSERT(bio_op(orig_bio) != REQ_OP_READ);
+
+	/* Reuse the bio embedded into the btrfs_bio for the last mirror */
+	if (dev_nr == bioc->num_stripes - 1) {
+		bio = orig_bio;
+		bio->bi_end_io = btrfs_orig_write_end_io;
+	} else {
+		bio = bio_alloc_clone(NULL, orig_bio, GFP_NOFS, &fs_bio_set);
+		bio_inc_remaining(orig_bio);
+		bio->bi_end_io = btrfs_clone_write_end_io;
+	}
+
+	bio->bi_private = &bioc->stripes[dev_nr];
+	bio->bi_iter.bi_sector = bioc->stripes[dev_nr].physical >> SECTOR_SHIFT;
+	bioc->stripes[dev_nr].bioc = bioc;
+	btrfs_submit_dev_bio(bioc->stripes[dev_nr].dev, bio);
+}
+
+void btrfs_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio, int mirror_num)
+{
+	u64 logical = bio->bi_iter.bi_sector << 9;
+	u64 length = bio->bi_iter.bi_size;
+	u64 map_length = length;
+	struct btrfs_io_context *bioc = NULL;
+	struct btrfs_io_stripe smap;
+	int ret;
+
+	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 (map_length < length) {
+		btrfs_crit(fs_info,
+			   "mapping failed logical %llu bio len %llu len %llu",
+			   logical, length, map_length);
+		BUG();
+	}
+
+	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_end_io = btrfs_simple_end_io;
+		btrfs_submit_dev_bio(smap.dev, bio);
+	} else if (bioc->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
+		/* Parity RAID write or read recovery */
+		bio->bi_private = bioc;
+		bio->bi_end_io = btrfs_raid56_end_io;
+		if (bio_op(bio) == REQ_OP_READ)
+			raid56_parity_recover(bio, bioc, mirror_num);
+		else
+			raid56_parity_write(bio, bioc);
+	} else {
+		/* Write to multiple mirrors */
+		int total_devs = bioc->num_stripes;
+		int dev_nr;
+
+		bioc->orig_bio = bio;
+		for (dev_nr = 0; dev_nr < total_devs; dev_nr++)
+			btrfs_submit_mirrored_bio(bioc, dev_nr);
+	}
+}
+
+int __init btrfs_bioset_init(void)
+{
+	if (bioset_init(&btrfs_bioset, BIO_POOL_SIZE,
+			offsetof(struct btrfs_bio, bio),
+			BIOSET_NEED_BVECS))
+		return -ENOMEM;
+	return 0;
+}
+
+void __cold btrfs_bioset_exit(void)
+{
+	bioset_exit(&btrfs_bioset);
+}
diff --git a/fs/btrfs/bio.h b/fs/btrfs/bio.h
new file mode 100644
index 0000000000000..4aa3bfc753911
--- /dev/null
+++ b/fs/btrfs/bio.h
@@ -0,0 +1,126 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2007 Oracle.  All rights reserved.
+ * Copyright (C) 2022 Christoph Hellwig.
+ */
+#ifndef BTRFS_BIO_H
+#define BTRFS_BIO_H
+
+#include <linux/bio.h>
+#include <linux/workqueue.h>
+#include "parent-check.h"
+
+struct btrfs_bio;
+struct btrfs_fs_info;
+
+#define BTRFS_BIO_INLINE_CSUM_SIZE	64
+
+/*
+ * Maximum number of sectors for a single bio to limit the size of the
+ * checksum array.  This matches the number of bio_vecs per bio and thus the
+ * I/O size for buffered I/O.
+ */
+#define BTRFS_MAX_BIO_SECTORS		(256)
+
+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.
+ */
+struct btrfs_bio {
+	unsigned int mirror_num:7;
+
+	/*
+	 * Extra indicator for metadata bios.
+	 * For some btrfs bios they use pages without a mapping, thus
+	 * we can not rely on page->mapping->host to determine if
+	 * it's a metadata bio.
+	 */
+	unsigned int is_metadata:1;
+	struct bvec_iter iter;
+
+	/* for direct I/O */
+	u64 file_offset;
+
+	/* @device is for stripe IO submission. */
+	struct btrfs_device *device;
+	union {
+		/* For data checksum verification. */
+		struct {
+			u8 *csum;
+			u8 csum_inline[BTRFS_BIO_INLINE_CSUM_SIZE];
+		};
+
+		/* For metadata parentness verification. */
+		struct btrfs_tree_parent_check parent_check;
+	};
+
+	/* End I/O information supplied to btrfs_bio_alloc */
+	btrfs_bio_end_io_t end_io;
+	void *private;
+
+	/* For read end I/O handling */
+	struct work_struct end_io_work;
+
+	/*
+	 * This member must come last, bio_alloc_bioset will allocate enough
+	 * bytes for entire btrfs_bio but relies on bio being last.
+	 */
+	struct bio bio;
+};
+
+static inline struct btrfs_bio *btrfs_bio(struct bio *bio)
+{
+	return container_of(bio, struct btrfs_bio, bio);
+}
+
+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 bio *btrfs_bio_clone_partial(struct bio *orig, u64 offset, u64 size,
+				    btrfs_bio_end_io_t end_io, void *private);
+
+
+static inline void btrfs_bio_end_io(struct btrfs_bio *bbio, blk_status_t status)
+{
+	bbio->bio.bi_status = status;
+	bbio->end_io(bbio);
+}
+
+static inline void btrfs_bio_free_csum(struct btrfs_bio *bbio)
+{
+	if (bbio->is_metadata)
+		return;
+	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))
+
+void btrfs_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio,
+		      int mirror_num);
+int btrfs_repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 start,
+			    u64 length, u64 logical, struct page *page,
+			    unsigned int pg_offset, int mirror_num);
+
+#endif /* BTRFS_BIO_H */
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 30adf430241e1..5122ca79f7ea4 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -27,7 +27,7 @@
 #include "disk-io.h"
 #include "transaction.h"
 #include "btrfs_inode.h"
-#include "volumes.h"
+#include "bio.h"
 #include "ordered-data.h"
 #include "compression.h"
 #include "extent_io.h"
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index f75e398d7b712..23b1443988ee3 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -22,6 +22,7 @@
 #include "accessors.h"
 #include "extent-tree.h"
 #include "relocation.h"
+#include "parent-check.h"
 
 static struct kmem_cache *btrfs_path_cachep;
 
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 91a088210e5ad..d5be259845d10 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -23,7 +23,7 @@
 #include "disk-io.h"
 #include "transaction.h"
 #include "btrfs_inode.h"
-#include "volumes.h"
+#include "bio.h"
 #include "print-tree.h"
 #include "locking.h"
 #include "tree-log.h"
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 17f599027c3de..900be08ade699 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -42,6 +42,7 @@
 #include "root-tree.h"
 #include "file-item.h"
 #include "orphan.h"
+#include "parent-check.h"
 
 #undef SCRAMBLE_DELAYED_REFS
 
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 65ba5c3658cf6..95d54b5834c09 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -20,7 +20,7 @@
 #include "extent_map.h"
 #include "ctree.h"
 #include "btrfs_inode.h"
-#include "volumes.h"
+#include "bio.h"
 #include "check-integrity.h"
 #include "locking.h"
 #include "rcu-string.h"
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index 352bbb33b76f0..5de73466b2ca2 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -14,7 +14,7 @@
 #include "ctree.h"
 #include "disk-io.h"
 #include "transaction.h"
-#include "volumes.h"
+#include "bio.h"
 #include "print-tree.h"
 #include "compression.h"
 #include "fs.h"
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 4248e6cabbdcb..905ea19df125b 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -43,7 +43,7 @@
 #include "ordered-data.h"
 #include "xattr.h"
 #include "tree-log.h"
-#include "volumes.h"
+#include "bio.h"
 #include "compression.h"
 #include "locking.h"
 #include "free-space-cache.h"
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index aa80e51bc8ca4..5e15796aa6dc3 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -35,6 +35,7 @@
 #include "file-item.h"
 #include "relocation.h"
 #include "super.h"
+#include "parent-check.h"
 
 /*
  * Relocation overview
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index ea83dd9f735a6..93f52ee85f6fe 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -35,7 +35,7 @@
 #include "print-tree.h"
 #include "props.h"
 #include "xattr.h"
-#include "volumes.h"
+#include "bio.h"
 #include "export.h"
 #include "compression.h"
 #include "rcu-string.h"
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index c9a8cbe837fef..2c4dd2b5369cf 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -29,6 +29,7 @@
 #include "file-item.h"
 #include "file.h"
 #include "orphan.h"
+#include "parent-check.h"
 
 #define MAX_CONFLICT_INODES 10
 
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index e51fd5f1042a6..acab20f2863d5 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -5,12 +5,9 @@
 
 #include <linux/sched.h>
 #include <linux/sched/mm.h>
-#include <linux/bio.h>
 #include <linux/slab.h>
-#include <linux/blkdev.h>
 #include <linux/ratelimit.h>
 #include <linux/kthread.h>
-#include <linux/raid/pq.h>
 #include <linux/semaphore.h>
 #include <linux/uuid.h>
 #include <linux/list_sort.h>
@@ -23,8 +20,6 @@
 #include "print-tree.h"
 #include "volumes.h"
 #include "raid56.h"
-#include "async-thread.h"
-#include "check-integrity.h"
 #include "rcu-string.h"
 #include "dev-replace.h"
 #include "sysfs.h"
@@ -41,8 +36,6 @@
 #include "scrub.h"
 #include "super.h"
 
-static struct bio_set btrfs_bioset;
-
 #define BTRFS_BLOCK_GROUP_STRIPE_MASK	(BTRFS_BLOCK_GROUP_RAID0 | \
 					 BTRFS_BLOCK_GROUP_RAID10 | \
 					 BTRFS_BLOCK_GROUP_RAID56_MASK)
@@ -255,11 +248,6 @@ out_overflow:;
 static int init_first_rw_device(struct btrfs_trans_handle *trans);
 static int btrfs_relocate_sys_chunks(struct btrfs_fs_info *fs_info);
 static void btrfs_dev_stat_print_on_load(struct btrfs_device *device);
-static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
-			     enum btrfs_map_op op, u64 logical, u64 *length,
-			     struct btrfs_io_context **bioc_ret,
-			     struct btrfs_io_stripe *smap,
-			     int *mirror_num_ret, int need_raid_map);
 
 /*
  * Device locking
@@ -6364,11 +6352,11 @@ static void set_io_stripe(struct btrfs_io_stripe *dst, const struct map_lookup *
 			stripe_offset + stripe_nr * map->stripe_len;
 }
 
-static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
-			     enum btrfs_map_op op, u64 logical, u64 *length,
-			     struct btrfs_io_context **bioc_ret,
-			     struct btrfs_io_stripe *smap,
-			     int *mirror_num_ret, int need_raid_map)
+int __btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
+		      u64 logical, u64 *length,
+		      struct btrfs_io_context **bioc_ret,
+		      struct btrfs_io_stripe *smap, int *mirror_num_ret,
+		      int need_raid_map)
 {
 	struct extent_map *em;
 	struct map_lookup *map;
@@ -6651,266 +6639,6 @@ int btrfs_map_sblock(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
 				 NULL, NULL, 1);
 }
 
-/*
- * 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)
-{
-	memset(bbio, 0, offsetof(struct btrfs_bio, bio));
-	bbio->end_io = end_io;
-	bbio->private = private;
-}
-
-/*
- * Allocate a btrfs_bio structure.  The btrfs_bio is the main I/O container for
- * btrfs, and is used for all I/O submitted through btrfs_submit_bio.
- *
- * Just like the underlying bio_alloc_bioset it will not fail as it is backed by
- * 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 bio *bio;
-
-	bio = bio_alloc_bioset(NULL, nr_vecs, opf, GFP_NOFS, &btrfs_bioset);
-	btrfs_bio_init(btrfs_bio(bio), end_io, private);
-	return bio;
-}
-
-struct bio *btrfs_bio_clone_partial(struct bio *orig, u64 offset, u64 size,
-				    btrfs_bio_end_io_t end_io, void *private)
-{
-	struct bio *bio;
-	struct btrfs_bio *bbio;
-
-	ASSERT(offset <= UINT_MAX && size <= UINT_MAX);
-
-	bio = bio_alloc_clone(orig->bi_bdev, orig, GFP_NOFS, &btrfs_bioset);
-	bbio = btrfs_bio(bio);
-	btrfs_bio_init(bbio, end_io, private);
-
-	bio_trim(bio, offset >> 9, size >> 9);
-	bbio->iter = bio->bi_iter;
-	return bio;
-}
-
-static void btrfs_log_dev_io_error(struct bio *bio, struct btrfs_device *dev)
-{
-	if (!dev || !dev->bdev)
-		return;
-	if (bio->bi_status != BLK_STS_IOERR && bio->bi_status != BLK_STS_TARGET)
-		return;
-
-	if (btrfs_op(bio) == BTRFS_MAP_WRITE)
-		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
-	if (!(bio->bi_opf & REQ_RAHEAD))
-		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_READ_ERRS);
-	if (bio->bi_opf & REQ_PREFLUSH)
-		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_FLUSH_ERRS);
-}
-
-static struct workqueue_struct *btrfs_end_io_wq(struct btrfs_fs_info *fs_info,
-						struct bio *bio)
-{
-	if (bio->bi_opf & REQ_META)
-		return fs_info->endio_meta_workers;
-	return fs_info->endio_workers;
-}
-
-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);
-}
-
-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);
-
-	btrfs_bio_counter_dec(fs_info);
-
-	if (bio->bi_status)
-		btrfs_log_dev_io_error(bio, bbio->device);
-
-	if (bio_op(bio) == REQ_OP_READ) {
-		INIT_WORK(&bbio->end_io_work, btrfs_end_bio_work);
-		queue_work(btrfs_end_io_wq(fs_info, bio), &bbio->end_io_work);
-	} else {
-		bbio->end_io(bbio);
-	}
-}
-
-static void btrfs_raid56_end_io(struct bio *bio)
-{
-	struct btrfs_io_context *bioc = bio->bi_private;
-	struct btrfs_bio *bbio = btrfs_bio(bio);
-
-	btrfs_bio_counter_dec(bioc->fs_info);
-	bbio->mirror_num = bioc->mirror_num;
-	bbio->end_io(bbio);
-
-	btrfs_put_bioc(bioc);
-}
-
-static void btrfs_orig_write_end_io(struct bio *bio)
-{
-	struct btrfs_io_stripe *stripe = bio->bi_private;
-	struct btrfs_io_context *bioc = stripe->bioc;
-	struct btrfs_bio *bbio = btrfs_bio(bio);
-
-	btrfs_bio_counter_dec(bioc->fs_info);
-
-	if (bio->bi_status) {
-		atomic_inc(&bioc->error);
-		btrfs_log_dev_io_error(bio, stripe->dev);
-	}
-
-	/*
-	 * Only send an error to the higher layers if it is beyond the tolerance
-	 * threshold.
-	 */
-	if (atomic_read(&bioc->error) > bioc->max_errors)
-		bio->bi_status = BLK_STS_IOERR;
-	else
-		bio->bi_status = BLK_STS_OK;
-
-	bbio->end_io(bbio);
-	btrfs_put_bioc(bioc);
-}
-
-static void btrfs_clone_write_end_io(struct bio *bio)
-{
-	struct btrfs_io_stripe *stripe = bio->bi_private;
-
-	if (bio->bi_status) {
-		atomic_inc(&stripe->bioc->error);
-		btrfs_log_dev_io_error(bio, stripe->dev);
-	}
-
-	/* Pass on control to the original bio this one was cloned from */
-	bio_endio(stripe->bioc->orig_bio);
-	bio_put(bio);
-}
-
-static void btrfs_submit_dev_bio(struct btrfs_device *dev, struct bio *bio)
-{
-	if (!dev || !dev->bdev ||
-	    test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state) ||
-	    (btrfs_op(bio) == BTRFS_MAP_WRITE &&
-	     !test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state))) {
-		bio_io_error(bio);
-		return;
-	}
-
-	bio_set_dev(bio, dev->bdev);
-
-	/*
-	 * For zone append writing, bi_sector must point the beginning of the
-	 * zone
-	 */
-	if (bio_op(bio) == REQ_OP_ZONE_APPEND) {
-		u64 physical = bio->bi_iter.bi_sector << SECTOR_SHIFT;
-
-		if (btrfs_dev_is_sequential(dev, physical)) {
-			u64 zone_start = round_down(physical,
-						    dev->fs_info->zone_size);
-
-			bio->bi_iter.bi_sector = zone_start >> SECTOR_SHIFT;
-		} else {
-			bio->bi_opf &= ~REQ_OP_ZONE_APPEND;
-			bio->bi_opf |= REQ_OP_WRITE;
-		}
-	}
-	btrfs_debug_in_rcu(dev->fs_info,
-	"%s: rw %d 0x%x, sector=%llu, dev=%lu (%s id %llu), size=%u",
-		__func__, bio_op(bio), bio->bi_opf, bio->bi_iter.bi_sector,
-		(unsigned long)dev->bdev->bd_dev, btrfs_dev_name(dev),
-		dev->devid, bio->bi_iter.bi_size);
-
-	btrfsic_check_bio(bio);
-	submit_bio(bio);
-}
-
-static void btrfs_submit_mirrored_bio(struct btrfs_io_context *bioc, int dev_nr)
-{
-	struct bio *orig_bio = bioc->orig_bio, *bio;
-
-	ASSERT(bio_op(orig_bio) != REQ_OP_READ);
-
-	/* Reuse the bio embedded into the btrfs_bio for the last mirror */
-	if (dev_nr == bioc->num_stripes - 1) {
-		bio = orig_bio;
-		bio->bi_end_io = btrfs_orig_write_end_io;
-	} else {
-		bio = bio_alloc_clone(NULL, orig_bio, GFP_NOFS, &fs_bio_set);
-		bio_inc_remaining(orig_bio);
-		bio->bi_end_io = btrfs_clone_write_end_io;
-	}
-
-	bio->bi_private = &bioc->stripes[dev_nr];
-	bio->bi_iter.bi_sector = bioc->stripes[dev_nr].physical >> SECTOR_SHIFT;
-	bioc->stripes[dev_nr].bioc = bioc;
-	btrfs_submit_dev_bio(bioc->stripes[dev_nr].dev, bio);
-}
-
-void btrfs_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio, int mirror_num)
-{
-	u64 logical = bio->bi_iter.bi_sector << 9;
-	u64 length = bio->bi_iter.bi_size;
-	u64 map_length = length;
-	struct btrfs_io_context *bioc = NULL;
-	struct btrfs_io_stripe smap;
-	int ret;
-
-	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 (map_length < length) {
-		btrfs_crit(fs_info,
-			   "mapping failed logical %llu bio len %llu len %llu",
-			   logical, length, map_length);
-		BUG();
-	}
-
-	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_end_io = btrfs_simple_end_io;
-		btrfs_submit_dev_bio(smap.dev, bio);
-	} else if (bioc->map_type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
-		/* Parity RAID write or read recovery */
-		bio->bi_private = bioc;
-		bio->bi_end_io = btrfs_raid56_end_io;
-		if (bio_op(bio) == REQ_OP_READ)
-			raid56_parity_recover(bio, bioc, mirror_num);
-		else
-			raid56_parity_write(bio, bioc);
-	} else {
-		/* Write to multiple mirrors */
-		int total_devs = bioc->num_stripes;
-		int dev_nr;
-
-		bioc->orig_bio = bio;
-		for (dev_nr = 0; dev_nr < total_devs; dev_nr++)
-			btrfs_submit_mirrored_bio(bioc, dev_nr);
-	}
-}
-
 static bool dev_args_match_fs_devices(const struct btrfs_dev_lookup_args *args,
 				      const struct btrfs_fs_devices *fs_devices)
 {
@@ -8440,17 +8168,3 @@ bool btrfs_repair_one_zone(struct btrfs_fs_info *fs_info, u64 logical)
 
 	return true;
 }
-
-int __init btrfs_bioset_init(void)
-{
-	if (bioset_init(&btrfs_bioset, BIO_POOL_SIZE,
-			offsetof(struct btrfs_bio, bio),
-			BIOSET_NEED_BVECS))
-		return -ENOMEM;
-	return 0;
-}
-
-void __cold btrfs_bioset_exit(void)
-{
-	bioset_exit(&btrfs_bioset);
-}
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 7467df319d3b2..b4ce6183bbf59 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -6,12 +6,10 @@
 #ifndef BTRFS_VOLUMES_H
 #define BTRFS_VOLUMES_H
 
-#include <linux/bio.h>
 #include <linux/sort.h>
 #include <linux/btrfs.h>
 #include "async-thread.h"
 #include "messages.h"
-#include "parent-check.h"
 #include "rcu-string.h"
 
 #define BTRFS_MAX_DATA_CHUNK_SIZE	(10ULL * SZ_1G)
@@ -373,8 +371,6 @@ struct btrfs_fs_devices {
 	enum btrfs_read_policy read_policy;
 };
 
-#define BTRFS_BIO_INLINE_CSUM_SIZE	64
-
 #define BTRFS_MAX_DEVS(info) ((BTRFS_MAX_ITEM_SIZE(info)	\
 			- sizeof(struct btrfs_chunk))		\
 			/ sizeof(struct btrfs_stripe) + 1)
@@ -384,107 +380,6 @@ struct btrfs_fs_devices {
 				- 2 * sizeof(struct btrfs_chunk))	\
 				/ sizeof(struct btrfs_stripe) + 1)
 
-/*
- * Maximum number of sectors for a single bio to limit the size of the
- * checksum array.  This matches the number of bio_vecs per bio and thus the
- * I/O size for buffered I/O.
- */
-#define BTRFS_MAX_BIO_SECTORS				(256)
-
-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.
- */
-struct btrfs_bio {
-	unsigned int mirror_num:7;
-
-	/*
-	 * Extra indicator for metadata bios.
-	 * For some btrfs bios they use pages without a mapping, thus
-	 * we can not rely on page->mapping->host to determine if
-	 * it's a metadata bio.
-	 */
-	unsigned int is_metadata:1;
-	struct bvec_iter iter;
-
-	/* for direct I/O */
-	u64 file_offset;
-
-	/* @device is for stripe IO submission. */
-	struct btrfs_device *device;
-	union {
-		/* For data checksum verification. */
-		struct {
-			u8 *csum;
-			u8 csum_inline[BTRFS_BIO_INLINE_CSUM_SIZE];
-		};
-
-		/* For metadata parentness verification. */
-		struct btrfs_tree_parent_check parent_check;
-	};
-
-	/* End I/O information supplied to btrfs_bio_alloc */
-	btrfs_bio_end_io_t end_io;
-	void *private;
-
-	/* For read end I/O handling */
-	struct work_struct end_io_work;
-
-	/*
-	 * This member must come last, bio_alloc_bioset will allocate enough
-	 * bytes for entire btrfs_bio but relies on bio being last.
-	 */
-	struct bio bio;
-};
-
-static inline struct btrfs_bio *btrfs_bio(struct bio *bio)
-{
-	return container_of(bio, struct btrfs_bio, bio);
-}
-
-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 bio *btrfs_bio_clone_partial(struct bio *orig, u64 offset, u64 size,
-				    btrfs_bio_end_io_t end_io, void *private);
-
-static inline void btrfs_bio_end_io(struct btrfs_bio *bbio, blk_status_t status)
-{
-	bbio->bio.bi_status = status;
-	bbio->end_io(bbio);
-}
-
-static inline void btrfs_bio_free_csum(struct btrfs_bio *bbio)
-{
-	if (bbio->is_metadata)
-		return;
-	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 {
@@ -641,6 +536,11 @@ int btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
 int btrfs_map_sblock(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
 		     u64 logical, u64 *length,
 		     struct btrfs_io_context **bioc_ret);
+int __btrfs_map_block(struct btrfs_fs_info *fs_info, enum btrfs_map_op op,
+		      u64 logical, u64 *length,
+		      struct btrfs_io_context **bioc_ret,
+		      struct btrfs_io_stripe *smap, int *mirror_num_ret,
+		      int need_raid_map);
 struct btrfs_discard_stripe *btrfs_map_discard(struct btrfs_fs_info *fs_info,
 					       u64 logical, u64 *length_ret,
 					       u32 *num_stripes);
@@ -652,7 +552,6 @@ int btrfs_read_chunk_tree(struct btrfs_fs_info *fs_info);
 struct btrfs_block_group *btrfs_create_chunk(struct btrfs_trans_handle *trans,
 					    u64 type);
 void btrfs_mapping_tree_free(struct extent_map_tree *tree);
-void btrfs_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio, int mirror_num);
 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 		       fmode_t flags, void *holder);
 struct btrfs_device *btrfs_scan_one_device(const char *path,
-- 
2.30.2

[PATCH 3/3] btrfs: move repair_io_failure to bio.c

[Christoph Hellwig]

repair_io_failure ties directly into all the glory low-level details of
mapping a bio with a logic address to the actual physical location.
Move it right below btrfs_submit_bio to keep all the related logic
together.

Also move btrfs_repair_eb_io_failure to its caller in disk-io.c now that
repair_io_failure is available in a header.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
 fs/btrfs/bio.c       |  90 +++++++++++++++++++++++++++++++++
 fs/btrfs/disk-io.c   |  24 +++++++++
 fs/btrfs/extent_io.c | 117 +------------------------------------------
 fs/btrfs/extent_io.h |   1 -
 4 files changed, 116 insertions(+), 116 deletions(-)

diff --git a/fs/btrfs/bio.c b/fs/btrfs/bio.c
index 194b927ef9ee4..25dc41790e0fc 100644
--- a/fs/btrfs/bio.c
+++ b/fs/btrfs/bio.c
@@ -276,6 +276,96 @@ void btrfs_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio, int mirror
 	}
 }
 
+/*
+ * Submit a repair write.
+ *
+ * This bypasses btrfs_submit_bio deliberately, as that writes all copies in a
+ * RAID setup.  Here we only want to write the one bad copy, so we do the
+ * mapping ourselves and submit the bio directly.
+ *
+ * The I/O is issued sychronously to block the repair read completion from
+ * freeing the bio.
+ */
+int btrfs_repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 start,
+			    u64 length, u64 logical, struct page *page,
+			    unsigned int pg_offset, int mirror_num)
+{
+	struct btrfs_device *dev;
+	struct bio_vec bvec;
+	struct bio bio;
+	u64 map_length = 0;
+	u64 sector;
+	struct btrfs_io_context *bioc = NULL;
+	int ret = 0;
+
+	ASSERT(!(fs_info->sb->s_flags & SB_RDONLY));
+	BUG_ON(!mirror_num);
+
+	if (btrfs_repair_one_zone(fs_info, logical))
+		return 0;
+
+	map_length = length;
+
+	/*
+	 * Avoid races with device replace and make sure our bioc has devices
+	 * associated to its stripes that don't go away while we are doing the
+	 * read repair operation.
+	 */
+	btrfs_bio_counter_inc_blocked(fs_info);
+	if (btrfs_is_parity_mirror(fs_info, logical, length)) {
+		/*
+		 * Note that we don't use BTRFS_MAP_WRITE because it's supposed
+		 * to update all raid stripes, but here we just want to correct
+		 * bad stripe, thus BTRFS_MAP_READ is abused to only get the bad
+		 * stripe's dev and sector.
+		 */
+		ret = btrfs_map_block(fs_info, BTRFS_MAP_READ, logical,
+				      &map_length, &bioc, 0);
+		if (ret)
+			goto out_counter_dec;
+		ASSERT(bioc->mirror_num == 1);
+	} else {
+		ret = btrfs_map_block(fs_info, BTRFS_MAP_WRITE, logical,
+				      &map_length, &bioc, mirror_num);
+		if (ret)
+			goto out_counter_dec;
+		BUG_ON(mirror_num != bioc->mirror_num);
+	}
+
+	sector = bioc->stripes[bioc->mirror_num - 1].physical >> 9;
+	dev = bioc->stripes[bioc->mirror_num - 1].dev;
+	btrfs_put_bioc(bioc);
+
+	if (!dev || !dev->bdev ||
+	    !test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state)) {
+		ret = -EIO;
+		goto out_counter_dec;
+	}
+
+	bio_init(&bio, dev->bdev, &bvec, 1, REQ_OP_WRITE | REQ_SYNC);
+	bio.bi_iter.bi_sector = sector;
+	__bio_add_page(&bio, page, length, pg_offset);
+
+	btrfsic_check_bio(&bio);
+	ret = submit_bio_wait(&bio);
+	if (ret) {
+		/* try to remap that extent elsewhere? */
+		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
+		goto out_bio_uninit;
+	}
+
+	btrfs_info_rl_in_rcu(fs_info,
+		"read error corrected: ino %llu off %llu (dev %s sector %llu)",
+			     ino, start, btrfs_dev_name(dev), sector);
+	ret = 0;
+
+out_bio_uninit:
+	bio_uninit(&bio);
+out_counter_dec:
+	btrfs_bio_counter_dec(fs_info);
+	return ret;
+}
+
 int __init btrfs_bioset_init(void)
 {
 	if (bioset_init(&btrfs_bioset, BIO_POOL_SIZE,
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index d5be259845d10..0888d484df80c 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -255,6 +255,30 @@ int btrfs_verify_level_key(struct extent_buffer *eb, int level,
 	return ret;
 }
 
+static int btrfs_repair_eb_io_failure(const struct extent_buffer *eb,
+				      int mirror_num)
+{
+	struct btrfs_fs_info *fs_info = eb->fs_info;
+	u64 start = eb->start;
+	int i, num_pages = num_extent_pages(eb);
+	int ret = 0;
+
+	if (sb_rdonly(fs_info->sb))
+		return -EROFS;
+
+	for (i = 0; i < num_pages; i++) {
+		struct page *p = eb->pages[i];
+
+		ret = btrfs_repair_io_failure(fs_info, 0, start, PAGE_SIZE,
+				start, p, start - page_offset(p), mirror_num);
+		if (ret)
+			break;
+		start += PAGE_SIZE;
+	}
+
+	return ret;
+}
+
 /*
  * helper to read a given tree block, doing retries as required when
  * the checksums don't match and we have alternate mirrors to try.
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 95d54b5834c09..8528e7d3f38fe 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -531,119 +531,6 @@ static void free_io_failure(struct btrfs_inode *inode,
 	kfree(rec);
 }
 
-/*
- * this bypasses the standard btrfs submit functions deliberately, as
- * the standard behavior is to write all copies in a raid setup. here we only
- * want to write the one bad copy. so we do the mapping for ourselves and issue
- * submit_bio directly.
- * to avoid any synchronization issues, wait for the data after writing, which
- * actually prevents the read that triggered the error from finishing.
- * currently, there can be no more than two copies of every data bit. thus,
- * exactly one rewrite is required.
- */
-static int repair_io_failure(struct btrfs_fs_info *fs_info, u64 ino, u64 start,
-			     u64 length, u64 logical, struct page *page,
-			     unsigned int pg_offset, int mirror_num)
-{
-	struct btrfs_device *dev;
-	struct bio_vec bvec;
-	struct bio bio;
-	u64 map_length = 0;
-	u64 sector;
-	struct btrfs_io_context *bioc = NULL;
-	int ret = 0;
-
-	ASSERT(!(fs_info->sb->s_flags & SB_RDONLY));
-	BUG_ON(!mirror_num);
-
-	if (btrfs_repair_one_zone(fs_info, logical))
-		return 0;
-
-	map_length = length;
-
-	/*
-	 * Avoid races with device replace and make sure our bioc has devices
-	 * associated to its stripes that don't go away while we are doing the
-	 * read repair operation.
-	 */
-	btrfs_bio_counter_inc_blocked(fs_info);
-	if (btrfs_is_parity_mirror(fs_info, logical, length)) {
-		/*
-		 * Note that we don't use BTRFS_MAP_WRITE because it's supposed
-		 * to update all raid stripes, but here we just want to correct
-		 * bad stripe, thus BTRFS_MAP_READ is abused to only get the bad
-		 * stripe's dev and sector.
-		 */
-		ret = btrfs_map_block(fs_info, BTRFS_MAP_READ, logical,
-				      &map_length, &bioc, 0);
-		if (ret)
-			goto out_counter_dec;
-		ASSERT(bioc->mirror_num == 1);
-	} else {
-		ret = btrfs_map_block(fs_info, BTRFS_MAP_WRITE, logical,
-				      &map_length, &bioc, mirror_num);
-		if (ret)
-			goto out_counter_dec;
-		BUG_ON(mirror_num != bioc->mirror_num);
-	}
-
-	sector = bioc->stripes[bioc->mirror_num - 1].physical >> 9;
-	dev = bioc->stripes[bioc->mirror_num - 1].dev;
-	btrfs_put_bioc(bioc);
-
-	if (!dev || !dev->bdev ||
-	    !test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state)) {
-		ret = -EIO;
-		goto out_counter_dec;
-	}
-
-	bio_init(&bio, dev->bdev, &bvec, 1, REQ_OP_WRITE | REQ_SYNC);
-	bio.bi_iter.bi_sector = sector;
-	__bio_add_page(&bio, page, length, pg_offset);
-
-	btrfsic_check_bio(&bio);
-	ret = submit_bio_wait(&bio);
-	if (ret) {
-		/* try to remap that extent elsewhere? */
-		btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
-		goto out_bio_uninit;
-	}
-
-	btrfs_info_rl_in_rcu(fs_info,
-		"read error corrected: ino %llu off %llu (dev %s sector %llu)",
-			     ino, start, btrfs_dev_name(dev), sector);
-	ret = 0;
-
-out_bio_uninit:
-	bio_uninit(&bio);
-out_counter_dec:
-	btrfs_bio_counter_dec(fs_info);
-	return ret;
-}
-
-int btrfs_repair_eb_io_failure(const struct extent_buffer *eb, int mirror_num)
-{
-	struct btrfs_fs_info *fs_info = eb->fs_info;
-	u64 start = eb->start;
-	int i, num_pages = num_extent_pages(eb);
-	int ret = 0;
-
-	if (sb_rdonly(fs_info->sb))
-		return -EROFS;
-
-	for (i = 0; i < num_pages; i++) {
-		struct page *p = eb->pages[i];
-
-		ret = repair_io_failure(fs_info, 0, start, PAGE_SIZE, start, p,
-					start - page_offset(p), mirror_num);
-		if (ret)
-			break;
-		start += PAGE_SIZE;
-	}
-
-	return ret;
-}
-
 static int next_mirror(const struct io_failure_record *failrec, int cur_mirror)
 {
 	if (cur_mirror == failrec->num_copies)
@@ -691,7 +578,7 @@ int btrfs_clean_io_failure(struct btrfs_inode *inode, u64 start,
 	mirror = failrec->this_mirror;
 	do {
 		mirror = prev_mirror(failrec, mirror);
-		repair_io_failure(fs_info, ino, start, failrec->len,
+		btrfs_repair_io_failure(fs_info, ino, start, failrec->len,
 				  failrec->logical, page, pg_offset, mirror);
 	} while (mirror != failrec->failed_mirror);
 
@@ -822,7 +709,7 @@ int btrfs_repair_one_sector(struct btrfs_inode *inode, struct btrfs_bio *failed_
 	 *
 	 * 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 repair_io_failure to do the rest for us.
+	 * 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) {
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index a0bafc7f6c075..9b486419854eb 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -245,7 +245,6 @@ int extent_invalidate_folio(struct extent_io_tree *tree,
 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);
-int btrfs_repair_eb_io_failure(const struct extent_buffer *eb, int mirror_num);
 
 /*
  * When IO fails, either with EIO or csum verification fails, we
-- 
2.30.2

Re: [PATCH 1/3] btrfs: move struct btrfs_tree_parent_check out of disk-io.h

[Josef Bacik]

On Tue, Nov 15, 2022 at 10:44:04AM +0100, Christoph Hellwig wrote:
> Move struct btrfs_tree_parent_check out of disk-io.h so that volumes.h
> an various .c files don't have to include disk-io.h just for it.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> Reviewed-by: Qu Wenruo <wqu@suse.com>

Reviewed-by: Josef Bacik <josef@toxicpanda.com>

Thanks,

Josef

Re: [PATCH 1/3] btrfs: move struct btrfs_tree_parent_check out of disk-io.h

[David Sterba]

On Tue, Nov 15, 2022 at 10:44:04AM +0100, Christoph Hellwig wrote:
> Move struct btrfs_tree_parent_check out of disk-io.h so that volumes.h
> an various .c files don't have to include disk-io.h just for it.

Splitting that from disk-io.h makes sense but why creating a new file
that has just the one structure? We have the tree-checker.h that seems
like a place for various checks so I'll move it there.

Re: move the low-level btrfs_bio code into a separate file v3

[David Sterba]

On Tue, Nov 15, 2022 at 10:44:03AM +0100, Christoph Hellwig wrote:
> Hi all,
> 
> this small series creates a new bio.c file (and a bio.h header for it)
> to contain all the "storage" layer code below btrfs_submit_bio.  The
> amount of code sitting below btrfs_submit_bio will grow a lot with
> the "consolidate btrfs checksumming, repair and bio splitting" series,
> so this pure code move series triest to prepare for that by making
> sure we have a neat file to add it to.
> 
> Changes since v2:
>  - rebased against the rcu_string changes in misc-next
> 
> Changes since v1:
>  - rebased to the latest misc-next branch
>  - added a new patch to move struct btrfs_tree_parent_check into a new
>    header to invoide include hell

Added to misc-next, thanks.

Re: [PATCH 1/3] btrfs: move struct btrfs_tree_parent_check out of disk-io.h

[Christoph Hellwig]

On Fri, Nov 18, 2022 at 03:07:23PM +0100, David Sterba wrote:
> On Tue, Nov 15, 2022 at 10:44:04AM +0100, Christoph Hellwig wrote:
> > Move struct btrfs_tree_parent_check out of disk-io.h so that volumes.h
> > an various .c files don't have to include disk-io.h just for it.
> 
> Splitting that from disk-io.h makes sense but why creating a new file
> that has just the one structure?

Because there is no other header where it obviously fits.

> We have the tree-checker.h that seems
> like a place for various checks so I'll move it there.

Despite the similar naming there's actually no overlap between the
functionality offered in tree-checker.h and these uses of
struct btrfs_tree_parent_check at all.

Re: [PATCH 1/3] btrfs: move struct btrfs_tree_parent_check out of disk-io.h

[David Sterba]

On Sun, Nov 20, 2022 at 01:41:14PM +0100, Christoph Hellwig wrote:
> On Fri, Nov 18, 2022 at 03:07:23PM +0100, David Sterba wrote:
> > On Tue, Nov 15, 2022 at 10:44:04AM +0100, Christoph Hellwig wrote:
> > > Move struct btrfs_tree_parent_check out of disk-io.h so that volumes.h
> > > an various .c files don't have to include disk-io.h just for it.
> > 
> > Splitting that from disk-io.h makes sense but why creating a new file
> > that has just the one structure?
> 
> Because there is no other header where it obviously fits.
> 
> > We have the tree-checker.h that seems
> > like a place for various checks so I'll move it there.
> 
> Despite the similar naming there's actually no overlap between the
> functionality offered in tree-checker.h and these uses of
> struct btrfs_tree_parent_check at all.

That's not true, the overlap is quite clear. Tree checker verifies
metadata blocks at read time from the available items in the leaves and
links between the parent/child nodes is another extension of that.
Functions like validate_extent_buffer are in disk-io.c but they are the
to tree checker functionality.