Adding upstream version 6.7.7.upstream/6.7.7

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 0 insertions, 2871 deletions

diff --git a/fs/btrfs/check-integrity.c b/fs/btrfs/check-integrity.c
deleted file mode 100644
index 3caf339c4b..0000000000
--- a/fs/btrfs/check-integrity.c
+++ /dev/null
@@ -1,2871 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Copyright (C) STRATO AG 2011.  All rights reserved.
- */
-
-/*
- * This module can be used to catch cases when the btrfs kernel
- * code executes write requests to the disk that bring the file
- * system in an inconsistent state. In such a state, a power-loss
- * or kernel panic event would cause that the data on disk is
- * lost or at least damaged.
- *
- * Code is added that examines all block write requests during
- * runtime (including writes of the super block). Three rules
- * are verified and an error is printed on violation of the
- * rules:
- * 1. It is not allowed to write a disk block which is
- *    currently referenced by the super block (either directly
- *    or indirectly).
- * 2. When a super block is written, it is verified that all
- *    referenced (directly or indirectly) blocks fulfill the
- *    following requirements:
- *    2a. All referenced blocks have either been present when
- *        the file system was mounted, (i.e., they have been
- *        referenced by the super block) or they have been
- *        written since then and the write completion callback
- *        was called and no write error was indicated and a
- *        FLUSH request to the device where these blocks are
- *        located was received and completed.
- *    2b. All referenced blocks need to have a generation
- *        number which is equal to the parent's number.
- *
- * One issue that was found using this module was that the log
- * tree on disk became temporarily corrupted because disk blocks
- * that had been in use for the log tree had been freed and
- * reused too early, while being referenced by the written super
- * block.
- *
- * The search term in the kernel log that can be used to filter
- * on the existence of detected integrity issues is
- * "btrfs: attempt".
- *
- * The integrity check is enabled via mount options. These
- * mount options are only supported if the integrity check
- * tool is compiled by defining BTRFS_FS_CHECK_INTEGRITY.
- *
- * Example #1, apply integrity checks to all metadata:
- * mount /dev/sdb1 /mnt -o check_int
- *
- * Example #2, apply integrity checks to all metadata and
- * to data extents:
- * mount /dev/sdb1 /mnt -o check_int_data
- *
- * Example #3, apply integrity checks to all metadata and dump
- * the tree that the super block references to kernel messages
- * each time after a super block was written:
- * mount /dev/sdb1 /mnt -o check_int,check_int_print_mask=263
- *
- * If the integrity check tool is included and activated in
- * the mount options, plenty of kernel memory is used, and
- * plenty of additional CPU cycles are spent. Enabling this
- * functionality is not intended for normal use. In most
- * cases, unless you are a btrfs developer who needs to verify
- * the integrity of (super)-block write requests, do not
- * enable the config option BTRFS_FS_CHECK_INTEGRITY to
- * include and compile the integrity check tool.
- *
- * Expect millions of lines of information in the kernel log with an
- * enabled check_int_print_mask. Therefore set LOG_BUF_SHIFT in the
- * kernel config to at least 26 (which is 64MB). Usually the value is
- * limited to 21 (which is 2MB) in init/Kconfig. The file needs to be
- * changed like this before LOG_BUF_SHIFT can be set to a high value:
- * config LOG_BUF_SHIFT
- *       int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
- *       range 12 30
- */
-
-#include <linux/sched.h>
-#include <linux/slab.h>
-#include <linux/mutex.h>
-#include <linux/blkdev.h>
-#include <linux/mm.h>
-#include <linux/string.h>
-#include <crypto/hash.h>
-#include "messages.h"
-#include "ctree.h"
-#include "disk-io.h"
-#include "transaction.h"
-#include "extent_io.h"
-#include "volumes.h"
-#include "print-tree.h"
-#include "locking.h"
-#include "check-integrity.h"
-#include "rcu-string.h"
-#include "compression.h"
-#include "accessors.h"
-
-#define BTRFSIC_BLOCK_HASHTABLE_SIZE 0x10000
-#define BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE 0x10000
-#define BTRFSIC_DEV2STATE_HASHTABLE_SIZE 0x100
-#define BTRFSIC_BLOCK_MAGIC_NUMBER 0x14491051
-#define BTRFSIC_BLOCK_LINK_MAGIC_NUMBER 0x11070807
-#define BTRFSIC_DEV2STATE_MAGIC_NUMBER 0x20111530
-#define BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER 20111300
-#define BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL (200 - 6)	/* in characters,
-							 * excluding " [...]" */
-#define BTRFSIC_GENERATION_UNKNOWN ((u64)-1)
-
-/*
- * The definition of the bitmask fields for the print_mask.
- * They are specified with the mount option check_integrity_print_mask.
- */
-#define BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE			0x00000001
-#define BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION		0x00000002
-#define BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE			0x00000004
-#define BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE			0x00000008
-#define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH			0x00000010
-#define BTRFSIC_PRINT_MASK_END_IO_BIO_BH			0x00000020
-#define BTRFSIC_PRINT_MASK_VERBOSE				0x00000040
-#define BTRFSIC_PRINT_MASK_VERY_VERBOSE				0x00000080
-#define BTRFSIC_PRINT_MASK_INITIAL_TREE				0x00000100
-#define BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES			0x00000200
-#define BTRFSIC_PRINT_MASK_INITIAL_DATABASE			0x00000400
-#define BTRFSIC_PRINT_MASK_NUM_COPIES				0x00000800
-#define BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS		0x00001000
-#define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE		0x00002000
-
-struct btrfsic_dev_state;
-struct btrfsic_state;
-
-struct btrfsic_block {
-	u32 magic_num;		/* only used for debug purposes */
-	unsigned int is_metadata:1;	/* if it is meta-data, not data-data */
-	unsigned int is_superblock:1;	/* if it is one of the superblocks */
-	unsigned int is_iodone:1;	/* if is done by lower subsystem */
-	unsigned int iodone_w_error:1;	/* error was indicated to endio */
-	unsigned int never_written:1;	/* block was added because it was
-					 * referenced, not because it was
-					 * written */
-	unsigned int mirror_num;	/* large enough to hold
-					 * BTRFS_SUPER_MIRROR_MAX */
-	struct btrfsic_dev_state *dev_state;
-	u64 dev_bytenr;		/* key, physical byte num on disk */
-	u64 logical_bytenr;	/* logical byte num on disk */
-	u64 generation;
-	struct btrfs_disk_key disk_key;	/* extra info to print in case of
-					 * issues, will not always be correct */
-	struct list_head collision_resolving_node;	/* list node */
-	struct list_head all_blocks_node;	/* list node */
-
-	/* the following two lists contain block_link items */
-	struct list_head ref_to_list;	/* list */
-	struct list_head ref_from_list;	/* list */
-	struct btrfsic_block *next_in_same_bio;
-	void *orig_bio_private;
-	bio_end_io_t *orig_bio_end_io;
-	blk_opf_t submit_bio_bh_rw;
-	u64 flush_gen; /* only valid if !never_written */
-};
-
-/*
- * Elements of this type are allocated dynamically and required because
- * each block object can refer to and can be ref from multiple blocks.
- * The key to lookup them in the hashtable is the dev_bytenr of
- * the block ref to plus the one from the block referred from.
- * The fact that they are searchable via a hashtable and that a
- * ref_cnt is maintained is not required for the btrfs integrity
- * check algorithm itself, it is only used to make the output more
- * beautiful in case that an error is detected (an error is defined
- * as a write operation to a block while that block is still referenced).
- */
-struct btrfsic_block_link {
-	u32 magic_num;		/* only used for debug purposes */
-	u32 ref_cnt;
-	struct list_head node_ref_to;	/* list node */
-	struct list_head node_ref_from;	/* list node */
-	struct list_head collision_resolving_node;	/* list node */
-	struct btrfsic_block *block_ref_to;
-	struct btrfsic_block *block_ref_from;
-	u64 parent_generation;
-};
-
-struct btrfsic_dev_state {
-	u32 magic_num;		/* only used for debug purposes */
-	struct block_device *bdev;
-	struct btrfsic_state *state;
-	struct list_head collision_resolving_node;	/* list node */
-	struct btrfsic_block dummy_block_for_bio_bh_flush;
-	u64 last_flush_gen;
-};
-
-struct btrfsic_block_hashtable {
-	struct list_head table[BTRFSIC_BLOCK_HASHTABLE_SIZE];
-};
-
-struct btrfsic_block_link_hashtable {
-	struct list_head table[BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE];
-};
-
-struct btrfsic_dev_state_hashtable {
-	struct list_head table[BTRFSIC_DEV2STATE_HASHTABLE_SIZE];
-};
-
-struct btrfsic_block_data_ctx {
-	u64 start;		/* virtual bytenr */
-	u64 dev_bytenr;		/* physical bytenr on device */
-	u32 len;
-	struct btrfsic_dev_state *dev;
-	char **datav;
-	struct page **pagev;
-	void *mem_to_free;
-};
-
-/* This structure is used to implement recursion without occupying
- * any stack space, refer to btrfsic_process_metablock() */
-struct btrfsic_stack_frame {
-	u32 magic;
-	u32 nr;
-	int error;
-	int i;
-	int limit_nesting;
-	int num_copies;
-	int mirror_num;
-	struct btrfsic_block *block;
-	struct btrfsic_block_data_ctx *block_ctx;
-	struct btrfsic_block *next_block;
-	struct btrfsic_block_data_ctx next_block_ctx;
-	struct btrfs_header *hdr;
-	struct btrfsic_stack_frame *prev;
-};
-
-/* Some state per mounted filesystem */
-struct btrfsic_state {
-	u32 print_mask;
-	int include_extent_data;
-	struct list_head all_blocks_list;
-	struct btrfsic_block_hashtable block_hashtable;
-	struct btrfsic_block_link_hashtable block_link_hashtable;
-	struct btrfs_fs_info *fs_info;
-	u64 max_superblock_generation;
-	struct btrfsic_block *latest_superblock;
-	u32 metablock_size;
-	u32 datablock_size;
-};
-
-static int btrfsic_process_metablock(struct btrfsic_state *state,
-				     struct btrfsic_block *block,
-				     struct btrfsic_block_data_ctx *block_ctx,
-				     int limit_nesting, int force_iodone_flag);
-static void btrfsic_read_from_block_data(
-	struct btrfsic_block_data_ctx *block_ctx,
-	void *dst, u32 offset, size_t len);
-static int btrfsic_create_link_to_next_block(
-		struct btrfsic_state *state,
-		struct btrfsic_block *block,
-		struct btrfsic_block_data_ctx
-		*block_ctx, u64 next_bytenr,
-		int limit_nesting,
-		struct btrfsic_block_data_ctx *next_block_ctx,
-		struct btrfsic_block **next_blockp,
-		int force_iodone_flag,
-		int *num_copiesp, int *mirror_nump,
-		struct btrfs_disk_key *disk_key,
-		u64 parent_generation);
-static int btrfsic_handle_extent_data(struct btrfsic_state *state,
-				      struct btrfsic_block *block,
-				      struct btrfsic_block_data_ctx *block_ctx,
-				      u32 item_offset, int force_iodone_flag);
-static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
-			     struct btrfsic_block_data_ctx *block_ctx_out,
-			     int mirror_num);
-static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx);
-static int btrfsic_read_block(struct btrfsic_state *state,
-			      struct btrfsic_block_data_ctx *block_ctx);
-static int btrfsic_process_written_superblock(
-		struct btrfsic_state *state,
-		struct btrfsic_block *const block,
-		struct btrfs_super_block *const super_hdr);
-static void btrfsic_bio_end_io(struct bio *bp);
-static int btrfsic_is_block_ref_by_superblock(const struct btrfsic_state *state,
-					      const struct btrfsic_block *block,
-					      int recursion_level);
-static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
-					struct btrfsic_block *const block,
-					int recursion_level);
-static void btrfsic_print_add_link(const struct btrfsic_state *state,
-				   const struct btrfsic_block_link *l);
-static void btrfsic_print_rem_link(const struct btrfsic_state *state,
-				   const struct btrfsic_block_link *l);
-static char btrfsic_get_block_type(const struct btrfsic_state *state,
-				   const struct btrfsic_block *block);
-static void btrfsic_dump_tree(const struct btrfsic_state *state);
-static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
-				  const struct btrfsic_block *block,
-				  int indent_level);
-static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
-		struct btrfsic_state *state,
-		struct btrfsic_block_data_ctx *next_block_ctx,
-		struct btrfsic_block *next_block,
-		struct btrfsic_block *from_block,
-		u64 parent_generation);
-static struct btrfsic_block *btrfsic_block_lookup_or_add(
-		struct btrfsic_state *state,
-		struct btrfsic_block_data_ctx *block_ctx,
-		const char *additional_string,
-		int is_metadata,
-		int is_iodone,
-		int never_written,
-		int mirror_num,
-		int *was_created);
-static int btrfsic_process_superblock_dev_mirror(
-		struct btrfsic_state *state,
-		struct btrfsic_dev_state *dev_state,
-		struct btrfs_device *device,
-		int superblock_mirror_num,
-		struct btrfsic_dev_state **selected_dev_state,
-		struct btrfs_super_block *selected_super);
-static struct btrfsic_dev_state *btrfsic_dev_state_lookup(dev_t dev);
-static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
-					   u64 bytenr,
-					   struct btrfsic_dev_state *dev_state,
-					   u64 dev_bytenr);
-
-static struct mutex btrfsic_mutex;
-static int btrfsic_is_initialized;
-static struct btrfsic_dev_state_hashtable btrfsic_dev_state_hashtable;
-
-
-static void btrfsic_block_init(struct btrfsic_block *b)
-{
-	b->magic_num = BTRFSIC_BLOCK_MAGIC_NUMBER;
-	b->dev_state = NULL;
-	b->dev_bytenr = 0;
-	b->logical_bytenr = 0;
-	b->generation = BTRFSIC_GENERATION_UNKNOWN;
-	b->disk_key.objectid = 0;
-	b->disk_key.type = 0;
-	b->disk_key.offset = 0;
-	b->is_metadata = 0;
-	b->is_superblock = 0;
-	b->is_iodone = 0;
-	b->iodone_w_error = 0;
-	b->never_written = 0;
-	b->mirror_num = 0;
-	b->next_in_same_bio = NULL;
-	b->orig_bio_private = NULL;
-	b->orig_bio_end_io = NULL;
-	INIT_LIST_HEAD(&b->collision_resolving_node);
-	INIT_LIST_HEAD(&b->all_blocks_node);
-	INIT_LIST_HEAD(&b->ref_to_list);
-	INIT_LIST_HEAD(&b->ref_from_list);
-	b->submit_bio_bh_rw = 0;
-	b->flush_gen = 0;
-}
-
-static struct btrfsic_block *btrfsic_block_alloc(void)
-{
-	struct btrfsic_block *b;
-
-	b = kzalloc(sizeof(*b), GFP_NOFS);
-	if (NULL != b)
-		btrfsic_block_init(b);
-
-	return b;
-}
-
-static void btrfsic_block_free(struct btrfsic_block *b)
-{
-	BUG_ON(!(NULL == b || BTRFSIC_BLOCK_MAGIC_NUMBER == b->magic_num));
-	kfree(b);
-}
-
-static void btrfsic_block_link_init(struct btrfsic_block_link *l)
-{
-	l->magic_num = BTRFSIC_BLOCK_LINK_MAGIC_NUMBER;
-	l->ref_cnt = 1;
-	INIT_LIST_HEAD(&l->node_ref_to);
-	INIT_LIST_HEAD(&l->node_ref_from);
-	INIT_LIST_HEAD(&l->collision_resolving_node);
-	l->block_ref_to = NULL;
-	l->block_ref_from = NULL;
-}
-
-static struct btrfsic_block_link *btrfsic_block_link_alloc(void)
-{
-	struct btrfsic_block_link *l;
-
-	l = kzalloc(sizeof(*l), GFP_NOFS);
-	if (NULL != l)
-		btrfsic_block_link_init(l);
-
-	return l;
-}
-
-static void btrfsic_block_link_free(struct btrfsic_block_link *l)
-{
-	BUG_ON(!(NULL == l || BTRFSIC_BLOCK_LINK_MAGIC_NUMBER == l->magic_num));
-	kfree(l);
-}
-
-static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds)
-{
-	ds->magic_num = BTRFSIC_DEV2STATE_MAGIC_NUMBER;
-	ds->bdev = NULL;
-	ds->state = NULL;
-	INIT_LIST_HEAD(&ds->collision_resolving_node);
-	ds->last_flush_gen = 0;
-	btrfsic_block_init(&ds->dummy_block_for_bio_bh_flush);
-	ds->dummy_block_for_bio_bh_flush.is_iodone = 1;
-	ds->dummy_block_for_bio_bh_flush.dev_state = ds;
-}
-
-static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void)
-{
-	struct btrfsic_dev_state *ds;
-
-	ds = kzalloc(sizeof(*ds), GFP_NOFS);
-	if (NULL != ds)
-		btrfsic_dev_state_init(ds);
-
-	return ds;
-}
-
-static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds)
-{
-	BUG_ON(!(NULL == ds ||
-		 BTRFSIC_DEV2STATE_MAGIC_NUMBER == ds->magic_num));
-	kfree(ds);
-}
-
-static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h)
-{
-	int i;
-
-	for (i = 0; i < BTRFSIC_BLOCK_HASHTABLE_SIZE; i++)
-		INIT_LIST_HEAD(h->table + i);
-}
-
-static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
-					struct btrfsic_block_hashtable *h)
-{
-	const unsigned int hashval =
-	    (((unsigned int)(b->dev_bytenr >> 16)) ^
-	     ((unsigned int)((uintptr_t)b->dev_state->bdev))) &
-	     (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
-
-	list_add(&b->collision_resolving_node, h->table + hashval);
-}
-
-static void btrfsic_block_hashtable_remove(struct btrfsic_block *b)
-{
-	list_del(&b->collision_resolving_node);
-}
-
-static struct btrfsic_block *btrfsic_block_hashtable_lookup(
-		struct block_device *bdev,
-		u64 dev_bytenr,
-		struct btrfsic_block_hashtable *h)
-{
-	const unsigned int hashval =
-	    (((unsigned int)(dev_bytenr >> 16)) ^
-	     ((unsigned int)((uintptr_t)bdev))) &
-	     (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
-	struct btrfsic_block *b;
-
-	list_for_each_entry(b, h->table + hashval, collision_resolving_node) {
-		if (b->dev_state->bdev == bdev && b->dev_bytenr == dev_bytenr)
-			return b;
-	}
-
-	return NULL;
-}
-
-static void btrfsic_block_link_hashtable_init(
-		struct btrfsic_block_link_hashtable *h)
-{
-	int i;
-
-	for (i = 0; i < BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE; i++)
-		INIT_LIST_HEAD(h->table + i);
-}
-
-static void btrfsic_block_link_hashtable_add(
-		struct btrfsic_block_link *l,
-		struct btrfsic_block_link_hashtable *h)
-{
-	const unsigned int hashval =
-	    (((unsigned int)(l->block_ref_to->dev_bytenr >> 16)) ^
-	     ((unsigned int)(l->block_ref_from->dev_bytenr >> 16)) ^
-	     ((unsigned int)((uintptr_t)l->block_ref_to->dev_state->bdev)) ^
-	     ((unsigned int)((uintptr_t)l->block_ref_from->dev_state->bdev)))
-	     & (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
-
-	BUG_ON(NULL == l->block_ref_to);
-	BUG_ON(NULL == l->block_ref_from);
-	list_add(&l->collision_resolving_node, h->table + hashval);
-}
-
-static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l)
-{
-	list_del(&l->collision_resolving_node);
-}
-
-static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
-		struct block_device *bdev_ref_to,
-		u64 dev_bytenr_ref_to,
-		struct block_device *bdev_ref_from,
-		u64 dev_bytenr_ref_from,
-		struct btrfsic_block_link_hashtable *h)
-{
-	const unsigned int hashval =
-	    (((unsigned int)(dev_bytenr_ref_to >> 16)) ^
-	     ((unsigned int)(dev_bytenr_ref_from >> 16)) ^
-	     ((unsigned int)((uintptr_t)bdev_ref_to)) ^
-	     ((unsigned int)((uintptr_t)bdev_ref_from))) &
-	     (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
-	struct btrfsic_block_link *l;
-
-	list_for_each_entry(l, h->table + hashval, collision_resolving_node) {
-		BUG_ON(NULL == l->block_ref_to);
-		BUG_ON(NULL == l->block_ref_from);
-		if (l->block_ref_to->dev_state->bdev == bdev_ref_to &&
-		    l->block_ref_to->dev_bytenr == dev_bytenr_ref_to &&
-		    l->block_ref_from->dev_state->bdev == bdev_ref_from &&
-		    l->block_ref_from->dev_bytenr == dev_bytenr_ref_from)
-			return l;
-	}
-
-	return NULL;
-}
-
-static void btrfsic_dev_state_hashtable_init(
-		struct btrfsic_dev_state_hashtable *h)
-{
-	int i;
-
-	for (i = 0; i < BTRFSIC_DEV2STATE_HASHTABLE_SIZE; i++)
-		INIT_LIST_HEAD(h->table + i);
-}
-
-static void btrfsic_dev_state_hashtable_add(
-		struct btrfsic_dev_state *ds,
-		struct btrfsic_dev_state_hashtable *h)
-{
-	const unsigned int hashval =
-	    (((unsigned int)((uintptr_t)ds->bdev->bd_dev)) &
-	     (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
-
-	list_add(&ds->collision_resolving_node, h->table + hashval);
-}
-
-static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds)
-{
-	list_del(&ds->collision_resolving_node);
-}
-
-static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(dev_t dev,
-		struct btrfsic_dev_state_hashtable *h)
-{
-	const unsigned int hashval =
-		dev & (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1);
-	struct btrfsic_dev_state *ds;
-
-	list_for_each_entry(ds, h->table + hashval, collision_resolving_node) {
-		if (ds->bdev->bd_dev == dev)
-			return ds;
-	}
-
-	return NULL;
-}
-
-static int btrfsic_process_superblock(struct btrfsic_state *state,
-				      struct btrfs_fs_devices *fs_devices)
-{
-	struct btrfs_super_block *selected_super;
-	struct list_head *dev_head = &fs_devices->devices;
-	struct btrfs_device *device;
-	struct btrfsic_dev_state *selected_dev_state = NULL;
-	int ret = 0;
-	int pass;
-
-	selected_super = kzalloc(sizeof(*selected_super), GFP_NOFS);
-	if (!selected_super)
-		return -ENOMEM;
-
-	list_for_each_entry(device, dev_head, dev_list) {
-		int i;
-		struct btrfsic_dev_state *dev_state;
-
-		if (!device->bdev || !device->name)
-			continue;
-
-		dev_state = btrfsic_dev_state_lookup(device->bdev->bd_dev);
-		BUG_ON(NULL == dev_state);
-		for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
-			ret = btrfsic_process_superblock_dev_mirror(
-					state, dev_state, device, i,
-					&selected_dev_state, selected_super);
-			if (0 != ret && 0 == i) {
-				kfree(selected_super);
-				return ret;
-			}
-		}
-	}
-
-	if (NULL == state->latest_superblock) {
-		pr_info("btrfsic: no superblock found!\n");
-		kfree(selected_super);
-		return -1;
-	}
-
-	for (pass = 0; pass < 3; pass++) {
-		int num_copies;
-		int mirror_num;
-		u64 next_bytenr;
-
-		switch (pass) {
-		case 0:
-			next_bytenr = btrfs_super_root(selected_super);
-			if (state->print_mask &
-			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
-				pr_info("root@%llu\n", next_bytenr);
-			break;
-		case 1:
-			next_bytenr = btrfs_super_chunk_root(selected_super);
-			if (state->print_mask &
-			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
-				pr_info("chunk@%llu\n", next_bytenr);
-			break;
-		case 2:
-			next_bytenr = btrfs_super_log_root(selected_super);
-			if (0 == next_bytenr)
-				continue;
-			if (state->print_mask &
-			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
-				pr_info("log@%llu\n", next_bytenr);
-			break;
-		}
-
-		num_copies = btrfs_num_copies(state->fs_info, next_bytenr,
-					      state->metablock_size);
-		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
-			pr_info("num_copies(log_bytenr=%llu) = %d\n",
-			       next_bytenr, num_copies);
-
-		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
-			struct btrfsic_block *next_block;
-			struct btrfsic_block_data_ctx tmp_next_block_ctx;
-			struct btrfsic_block_link *l;
-
-			ret = btrfsic_map_block(state, next_bytenr,
-						state->metablock_size,
-						&tmp_next_block_ctx,
-						mirror_num);
-			if (ret) {
-				pr_info("btrfsic: btrfsic_map_block(root @%llu, mirror %d) failed!\n",
-				       next_bytenr, mirror_num);
-				kfree(selected_super);
-				return -1;
-			}
-
-			next_block = btrfsic_block_hashtable_lookup(
-					tmp_next_block_ctx.dev->bdev,
-					tmp_next_block_ctx.dev_bytenr,
-					&state->block_hashtable);
-			BUG_ON(NULL == next_block);
-
-			l = btrfsic_block_link_hashtable_lookup(
-					tmp_next_block_ctx.dev->bdev,
-					tmp_next_block_ctx.dev_bytenr,
-					state->latest_superblock->dev_state->
-					bdev,
-					state->latest_superblock->dev_bytenr,
-					&state->block_link_hashtable);
-			BUG_ON(NULL == l);
-
-			ret = btrfsic_read_block(state, &tmp_next_block_ctx);
-			if (ret < (int)PAGE_SIZE) {
-				pr_info("btrfsic: read @logical %llu failed!\n",
-				       tmp_next_block_ctx.start);
-				btrfsic_release_block_ctx(&tmp_next_block_ctx);
-				kfree(selected_super);
-				return -1;
-			}
-
-			ret = btrfsic_process_metablock(state,
-							next_block,
-							&tmp_next_block_ctx,
-							BTRFS_MAX_LEVEL + 3, 1);
-			btrfsic_release_block_ctx(&tmp_next_block_ctx);
-		}
-	}
-
-	kfree(selected_super);
-	return ret;
-}
-
-static int btrfsic_process_superblock_dev_mirror(
-		struct btrfsic_state *state,
-		struct btrfsic_dev_state *dev_state,
-		struct btrfs_device *device,
-		int superblock_mirror_num,
-		struct btrfsic_dev_state **selected_dev_state,
-		struct btrfs_super_block *selected_super)
-{
-	struct btrfs_fs_info *fs_info = state->fs_info;
-	struct btrfs_super_block *super_tmp;
-	u64 dev_bytenr;
-	struct btrfsic_block *superblock_tmp;
-	int pass;
-	struct block_device *const superblock_bdev = device->bdev;
-	struct page *page;
-	struct address_space *mapping = superblock_bdev->bd_inode->i_mapping;
-	int ret = 0;
-
-	/* super block bytenr is always the unmapped device bytenr */
-	dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
-	if (dev_bytenr + BTRFS_SUPER_INFO_SIZE > device->commit_total_bytes)
-		return -1;
-
-	page = read_cache_page_gfp(mapping, dev_bytenr >> PAGE_SHIFT, GFP_NOFS);
-	if (IS_ERR(page))
-		return -1;
-
-	super_tmp = page_address(page);
-
-	if (btrfs_super_bytenr(super_tmp) != dev_bytenr ||
-	    btrfs_super_magic(super_tmp) != BTRFS_MAGIC ||
-	    memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE) ||
-	    btrfs_super_nodesize(super_tmp) != state->metablock_size ||
-	    btrfs_super_sectorsize(super_tmp) != state->datablock_size) {
-		ret = 0;
-		goto out;
-	}
-
-	superblock_tmp =
-	    btrfsic_block_hashtable_lookup(superblock_bdev,
-					   dev_bytenr,
-					   &state->block_hashtable);
-	if (NULL == superblock_tmp) {
-		superblock_tmp = btrfsic_block_alloc();
-		if (NULL == superblock_tmp) {
-			ret = -1;
-			goto out;
-		}
-		/* for superblock, only the dev_bytenr makes sense */
-		superblock_tmp->dev_bytenr = dev_bytenr;
-		superblock_tmp->dev_state = dev_state;
-		superblock_tmp->logical_bytenr = dev_bytenr;
-		superblock_tmp->generation = btrfs_super_generation(super_tmp);
-		superblock_tmp->is_metadata = 1;
-		superblock_tmp->is_superblock = 1;
-		superblock_tmp->is_iodone = 1;
-		superblock_tmp->never_written = 0;
-		superblock_tmp->mirror_num = 1 + superblock_mirror_num;
-		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
-			btrfs_info_in_rcu(fs_info,
-			"new initial S-block (bdev %p, %s) @%llu (%pg/%llu/%d)",
-				     superblock_bdev,
-				     btrfs_dev_name(device), dev_bytenr,
-				     dev_state->bdev, dev_bytenr,
-				     superblock_mirror_num);
-		list_add(&superblock_tmp->all_blocks_node,
-			 &state->all_blocks_list);
-		btrfsic_block_hashtable_add(superblock_tmp,
-					    &state->block_hashtable);
-	}
-
-	/* select the one with the highest generation field */
-	if (btrfs_super_generation(super_tmp) >
-	    state->max_superblock_generation ||
-	    0 == state->max_superblock_generation) {
-		memcpy(selected_super, super_tmp, sizeof(*selected_super));
-		*selected_dev_state = dev_state;
-		state->max_superblock_generation =
-		    btrfs_super_generation(super_tmp);
-		state->latest_superblock = superblock_tmp;
-	}
-
-	for (pass = 0; pass < 3; pass++) {
-		u64 next_bytenr;
-		int num_copies;
-		int mirror_num;
-		const char *additional_string = NULL;
-		struct btrfs_disk_key tmp_disk_key;
-
-		tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
-		tmp_disk_key.offset = 0;
-		switch (pass) {
-		case 0:
-			btrfs_set_disk_key_objectid(&tmp_disk_key,
-						    BTRFS_ROOT_TREE_OBJECTID);
-			additional_string = "initial root ";
-			next_bytenr = btrfs_super_root(super_tmp);
-			break;
-		case 1:
-			btrfs_set_disk_key_objectid(&tmp_disk_key,
-						    BTRFS_CHUNK_TREE_OBJECTID);
-			additional_string = "initial chunk ";
-			next_bytenr = btrfs_super_chunk_root(super_tmp);
-			break;
-		case 2:
-			btrfs_set_disk_key_objectid(&tmp_disk_key,
-						    BTRFS_TREE_LOG_OBJECTID);
-			additional_string = "initial log ";
-			next_bytenr = btrfs_super_log_root(super_tmp);
-			if (0 == next_bytenr)
-				continue;
-			break;
-		}
-
-		num_copies = btrfs_num_copies(fs_info, next_bytenr,
-					      state->metablock_size);
-		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
-			pr_info("num_copies(log_bytenr=%llu) = %d\n",
-			       next_bytenr, num_copies);
-		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
-			struct btrfsic_block *next_block;
-			struct btrfsic_block_data_ctx tmp_next_block_ctx;
-			struct btrfsic_block_link *l;
-
-			if (btrfsic_map_block(state, next_bytenr,
-					      state->metablock_size,
-					      &tmp_next_block_ctx,
-					      mirror_num)) {
-				pr_info("btrfsic: btrfsic_map_block(bytenr @%llu, mirror %d) failed!\n",
-				       next_bytenr, mirror_num);
-				ret = -1;
-				goto out;
-			}
-
-			next_block = btrfsic_block_lookup_or_add(
-					state, &tmp_next_block_ctx,
-					additional_string, 1, 1, 0,
-					mirror_num, NULL);
-			if (NULL == next_block) {
-				btrfsic_release_block_ctx(&tmp_next_block_ctx);
-				ret = -1;
-				goto out;
-			}
-
-			next_block->disk_key = tmp_disk_key;
-			next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
-			l = btrfsic_block_link_lookup_or_add(
-					state, &tmp_next_block_ctx,
-					next_block, superblock_tmp,
-					BTRFSIC_GENERATION_UNKNOWN);
-			btrfsic_release_block_ctx(&tmp_next_block_ctx);
-			if (NULL == l) {
-				ret = -1;
-				goto out;
-			}
-		}
-	}
-	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES)
-		btrfsic_dump_tree_sub(state, superblock_tmp, 0);
-
-out:
-	put_page(page);
-	return ret;
-}
-
-static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void)
-{
-	struct btrfsic_stack_frame *sf;
-
-	sf = kzalloc(sizeof(*sf), GFP_NOFS);
-	if (sf)
-		sf->magic = BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER;
-	return sf;
-}
-
-static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf)
-{
-	BUG_ON(!(NULL == sf ||
-		 BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER == sf->magic));
-	kfree(sf);
-}
-
-static noinline_for_stack int btrfsic_process_metablock(
-		struct btrfsic_state *state,
-		struct btrfsic_block *const first_block,
-		struct btrfsic_block_data_ctx *const first_block_ctx,
-		int first_limit_nesting, int force_iodone_flag)
-{
-	struct btrfsic_stack_frame initial_stack_frame = { 0 };
-	struct btrfsic_stack_frame *sf;
-	struct btrfsic_stack_frame *next_stack;
-	struct btrfs_header *const first_hdr =
-		(struct btrfs_header *)first_block_ctx->datav[0];
-
-	BUG_ON(!first_hdr);
-	sf = &initial_stack_frame;
-	sf->error = 0;
-	sf->i = -1;
-	sf->limit_nesting = first_limit_nesting;
-	sf->block = first_block;
-	sf->block_ctx = first_block_ctx;
-	sf->next_block = NULL;
-	sf->hdr = first_hdr;
-	sf->prev = NULL;
-
-continue_with_new_stack_frame:
-	sf->block->generation = btrfs_stack_header_generation(sf->hdr);
-	if (0 == sf->hdr->level) {
-		struct btrfs_leaf *const leafhdr =
-		    (struct btrfs_leaf *)sf->hdr;
-
-		if (-1 == sf->i) {
-			sf->nr = btrfs_stack_header_nritems(&leafhdr->header);
-
-			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
-				pr_info("leaf %llu items %d generation %llu owner %llu\n",
-				       sf->block_ctx->start, sf->nr,
-				       btrfs_stack_header_generation(
-					       &leafhdr->header),
-				       btrfs_stack_header_owner(
-					       &leafhdr->header));
-		}
-
-continue_with_current_leaf_stack_frame:
-		if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
-			sf->i++;
-			sf->num_copies = 0;
-		}
-
-		if (sf->i < sf->nr) {
-			struct btrfs_item disk_item;
-			u32 disk_item_offset =
-				(uintptr_t)(leafhdr->items + sf->i) -
-				(uintptr_t)leafhdr;
-			struct btrfs_disk_key *disk_key;
-			u8 type;
-			u32 item_offset;
-			u32 item_size;
-
-			if (disk_item_offset + sizeof(struct btrfs_item) >
-			    sf->block_ctx->len) {
-leaf_item_out_of_bounce_error:
-				pr_info(
-		"btrfsic: leaf item out of bounce at logical %llu, dev %pg\n",
-				       sf->block_ctx->start,
-				       sf->block_ctx->dev->bdev);
-				goto one_stack_frame_backwards;
-			}
-			btrfsic_read_from_block_data(sf->block_ctx,
-						     &disk_item,
-						     disk_item_offset,
-						     sizeof(struct btrfs_item));
-			item_offset = btrfs_stack_item_offset(&disk_item);
-			item_size = btrfs_stack_item_size(&disk_item);
-			disk_key = &disk_item.key;
-			type = btrfs_disk_key_type(disk_key);
-
-			if (BTRFS_ROOT_ITEM_KEY == type) {
-				struct btrfs_root_item root_item;
-				u32 root_item_offset;
-				u64 next_bytenr;
-
-				root_item_offset = item_offset +
-					offsetof(struct btrfs_leaf, items);
-				if (root_item_offset + item_size >
-				    sf->block_ctx->len)
-					goto leaf_item_out_of_bounce_error;
-				btrfsic_read_from_block_data(
-					sf->block_ctx, &root_item,
-					root_item_offset,
-					item_size);
-				next_bytenr = btrfs_root_bytenr(&root_item);
-
-				sf->error =
-				    btrfsic_create_link_to_next_block(
-						state,
-						sf->block,
-						sf->block_ctx,
-						next_bytenr,
-						sf->limit_nesting,
-						&sf->next_block_ctx,
-						&sf->next_block,
-						force_iodone_flag,
-						&sf->num_copies,
-						&sf->mirror_num,
-						disk_key,
-						btrfs_root_generation(
-						&root_item));
-				if (sf->error)
-					goto one_stack_frame_backwards;
-
-				if (NULL != sf->next_block) {
-					struct btrfs_header *const next_hdr =
-					    (struct btrfs_header *)
-					    sf->next_block_ctx.datav[0];
-
-					next_stack =
-					    btrfsic_stack_frame_alloc();
-					if (NULL == next_stack) {
-						sf->error = -1;
-						btrfsic_release_block_ctx(
-								&sf->
-								next_block_ctx);
-						goto one_stack_frame_backwards;
-					}
-
-					next_stack->i = -1;
-					next_stack->block = sf->next_block;
-					next_stack->block_ctx =
-					    &sf->next_block_ctx;
-					next_stack->next_block = NULL;
-					next_stack->hdr = next_hdr;
-					next_stack->limit_nesting =
-					    sf->limit_nesting - 1;
-					next_stack->prev = sf;
-					sf = next_stack;
-					goto continue_with_new_stack_frame;
-				}
-			} else if (BTRFS_EXTENT_DATA_KEY == type &&
-				   state->include_extent_data) {
-				sf->error = btrfsic_handle_extent_data(
-						state,
-						sf->block,
-						sf->block_ctx,
-						item_offset,
-						force_iodone_flag);
-				if (sf->error)
-					goto one_stack_frame_backwards;
-			}
-
-			goto continue_with_current_leaf_stack_frame;
-		}
-	} else {
-		struct btrfs_node *const nodehdr = (struct btrfs_node *)sf->hdr;
-
-		if (-1 == sf->i) {
-			sf->nr = btrfs_stack_header_nritems(&nodehdr->header);
-
-			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
-				pr_info("node %llu level %d items %d generation %llu owner %llu\n",
-				       sf->block_ctx->start,
-				       nodehdr->header.level, sf->nr,
-				       btrfs_stack_header_generation(
-				       &nodehdr->header),
-				       btrfs_stack_header_owner(
-				       &nodehdr->header));
-		}
-
-continue_with_current_node_stack_frame:
-		if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
-			sf->i++;
-			sf->num_copies = 0;
-		}
-
-		if (sf->i < sf->nr) {
-			struct btrfs_key_ptr key_ptr;
-			u32 key_ptr_offset;
-			u64 next_bytenr;
-
-			key_ptr_offset = (uintptr_t)(nodehdr->ptrs + sf->i) -
-					  (uintptr_t)nodehdr;
-			if (key_ptr_offset + sizeof(struct btrfs_key_ptr) >
-			    sf->block_ctx->len) {
-				pr_info(
-		"btrfsic: node item out of bounce at logical %llu, dev %pg\n",
-				       sf->block_ctx->start,
-				       sf->block_ctx->dev->bdev);
-				goto one_stack_frame_backwards;
-			}
-			btrfsic_read_from_block_data(
-				sf->block_ctx, &key_ptr, key_ptr_offset,
-				sizeof(struct btrfs_key_ptr));
-			next_bytenr = btrfs_stack_key_blockptr(&key_ptr);
-
-			sf->error = btrfsic_create_link_to_next_block(
-					state,
-					sf->block,
-					sf->block_ctx,
-					next_bytenr,
-					sf->limit_nesting,
-					&sf->next_block_ctx,
-					&sf->next_block,
-					force_iodone_flag,
-					&sf->num_copies,
-					&sf->mirror_num,
-					&key_ptr.key,
-					btrfs_stack_key_generation(&key_ptr));
-			if (sf->error)
-				goto one_stack_frame_backwards;
-
-			if (NULL != sf->next_block) {
-				struct btrfs_header *const next_hdr =
-				    (struct btrfs_header *)
-				    sf->next_block_ctx.datav[0];
-
-				next_stack = btrfsic_stack_frame_alloc();
-				if (NULL == next_stack) {
-					sf->error = -1;
-					goto one_stack_frame_backwards;
-				}
-
-				next_stack->i = -1;
-				next_stack->block = sf->next_block;
-				next_stack->block_ctx = &sf->next_block_ctx;
-				next_stack->next_block = NULL;
-				next_stack->hdr = next_hdr;
-				next_stack->limit_nesting =
-				    sf->limit_nesting - 1;
-				next_stack->prev = sf;
-				sf = next_stack;
-				goto continue_with_new_stack_frame;
-			}
-
-			goto continue_with_current_node_stack_frame;
-		}
-	}
-
-one_stack_frame_backwards:
-	if (NULL != sf->prev) {
-		struct btrfsic_stack_frame *const prev = sf->prev;
-
-		/* the one for the initial block is freed in the caller */
-		btrfsic_release_block_ctx(sf->block_ctx);
-
-		if (sf->error) {
-			prev->error = sf->error;
-			btrfsic_stack_frame_free(sf);
-			sf = prev;
-			goto one_stack_frame_backwards;
-		}
-
-		btrfsic_stack_frame_free(sf);
-		sf = prev;
-		goto continue_with_new_stack_frame;
-	} else {
-		BUG_ON(&initial_stack_frame != sf);
-	}
-
-	return sf->error;
-}
-
-static void btrfsic_read_from_block_data(
-	struct btrfsic_block_data_ctx *block_ctx,
-	void *dstv, u32 offset, size_t len)
-{
-	size_t cur;
-	size_t pgoff;
-	char *kaddr;
-	char *dst = (char *)dstv;
-	size_t start_offset = offset_in_page(block_ctx->start);
-	unsigned long i = (start_offset + offset) >> PAGE_SHIFT;
-
-	WARN_ON(offset + len > block_ctx->len);
-	pgoff = offset_in_page(start_offset + offset);
-
-	while (len > 0) {
-		cur = min(len, ((size_t)PAGE_SIZE - pgoff));
-		BUG_ON(i >= DIV_ROUND_UP(block_ctx->len, PAGE_SIZE));
-		kaddr = block_ctx->datav[i];
-		memcpy(dst, kaddr + pgoff, cur);
-
-		dst += cur;
-		len -= cur;
-		pgoff = 0;
-		i++;
-	}
-}
-
-static int btrfsic_create_link_to_next_block(
-		struct btrfsic_state *state,
-		struct btrfsic_block *block,
-		struct btrfsic_block_data_ctx *block_ctx,
-		u64 next_bytenr,
-		int limit_nesting,
-		struct btrfsic_block_data_ctx *next_block_ctx,
-		struct btrfsic_block **next_blockp,
-		int force_iodone_flag,
-		int *num_copiesp, int *mirror_nump,
-		struct btrfs_disk_key *disk_key,
-		u64 parent_generation)
-{
-	struct btrfs_fs_info *fs_info = state->fs_info;
-	struct btrfsic_block *next_block = NULL;
-	int ret;
-	struct btrfsic_block_link *l;
-	int did_alloc_block_link;
-	int block_was_created;
-
-	*next_blockp = NULL;
-	if (0 == *num_copiesp) {
-		*num_copiesp = btrfs_num_copies(fs_info, next_bytenr,
-						state->metablock_size);
-		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
-			pr_info("num_copies(log_bytenr=%llu) = %d\n",
-			       next_bytenr, *num_copiesp);
-		*mirror_nump = 1;
-	}
-
-	if (*mirror_nump > *num_copiesp)
-		return 0;
-
-	if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
-		pr_info("btrfsic_create_link_to_next_block(mirror_num=%d)\n",
-		       *mirror_nump);
-	ret = btrfsic_map_block(state, next_bytenr,
-				state->metablock_size,
-				next_block_ctx, *mirror_nump);
-	if (ret) {
-		pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
-		       next_bytenr, *mirror_nump);
-		btrfsic_release_block_ctx(next_block_ctx);
-		*next_blockp = NULL;
-		return -1;
-	}
-
-	next_block = btrfsic_block_lookup_or_add(state,
-						 next_block_ctx, "referenced ",
-						 1, force_iodone_flag,
-						 !force_iodone_flag,
-						 *mirror_nump,
-						 &block_was_created);
-	if (NULL == next_block) {
-		btrfsic_release_block_ctx(next_block_ctx);
-		*next_blockp = NULL;
-		return -1;
-	}
-	if (block_was_created) {
-		l = NULL;
-		next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
-	} else {
-		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE) {
-			if (next_block->logical_bytenr != next_bytenr &&
-			    !(!next_block->is_metadata &&
-			      0 == next_block->logical_bytenr))
-				pr_info(
-"referenced block @%llu (%pg/%llu/%d) found in hash table, %c, bytenr mismatch (!= stored %llu)\n",
-				       next_bytenr, next_block_ctx->dev->bdev,
-				       next_block_ctx->dev_bytenr, *mirror_nump,
-				       btrfsic_get_block_type(state,
-							      next_block),
-				       next_block->logical_bytenr);
-			else
-				pr_info(
-		"referenced block @%llu (%pg/%llu/%d) found in hash table, %c\n",
-				       next_bytenr, next_block_ctx->dev->bdev,
-				       next_block_ctx->dev_bytenr, *mirror_nump,
-				       btrfsic_get_block_type(state,
-							      next_block));
-		}
-		next_block->logical_bytenr = next_bytenr;
-
-		next_block->mirror_num = *mirror_nump;
-		l = btrfsic_block_link_hashtable_lookup(
-				next_block_ctx->dev->bdev,
-				next_block_ctx->dev_bytenr,
-				block_ctx->dev->bdev,
-				block_ctx->dev_bytenr,
-				&state->block_link_hashtable);
-	}
-
-	next_block->disk_key = *disk_key;
-	if (NULL == l) {
-		l = btrfsic_block_link_alloc();
-		if (NULL == l) {
-			btrfsic_release_block_ctx(next_block_ctx);
-			*next_blockp = NULL;
-			return -1;
-		}
-
-		did_alloc_block_link = 1;
-		l->block_ref_to = next_block;
-		l->block_ref_from = block;
-		l->ref_cnt = 1;
-		l->parent_generation = parent_generation;
-
-		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
-			btrfsic_print_add_link(state, l);
-
-		list_add(&l->node_ref_to, &block->ref_to_list);
-		list_add(&l->node_ref_from, &next_block->ref_from_list);
-
-		btrfsic_block_link_hashtable_add(l,
-						 &state->block_link_hashtable);
-	} else {
-		did_alloc_block_link = 0;
-		if (0 == limit_nesting) {
-			l->ref_cnt++;
-			l->parent_generation = parent_generation;
-			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
-				btrfsic_print_add_link(state, l);
-		}
-	}
-
-	if (limit_nesting > 0 && did_alloc_block_link) {
-		ret = btrfsic_read_block(state, next_block_ctx);
-		if (ret < (int)next_block_ctx->len) {
-			pr_info("btrfsic: read block @logical %llu failed!\n",
-			       next_bytenr);
-			btrfsic_release_block_ctx(next_block_ctx);
-			*next_blockp = NULL;
-			return -1;
-		}
-
-		*next_blockp = next_block;
-	} else {
-		*next_blockp = NULL;
-	}
-	(*mirror_nump)++;
-
-	return 0;
-}
-
-static int btrfsic_handle_extent_data(
-		struct btrfsic_state *state,
-		struct btrfsic_block *block,
-		struct btrfsic_block_data_ctx *block_ctx,
-		u32 item_offset, int force_iodone_flag)
-{
-	struct btrfs_fs_info *fs_info = state->fs_info;
-	struct btrfs_file_extent_item file_extent_item;
-	u64 file_extent_item_offset;
-	u64 next_bytenr;
-	u64 num_bytes;
-	u64 generation;
-	struct btrfsic_block_link *l;
-	int ret;
-
-	file_extent_item_offset = offsetof(struct btrfs_leaf, items) +
-				  item_offset;
-	if (file_extent_item_offset +
-	    offsetof(struct btrfs_file_extent_item, disk_num_bytes) >
-	    block_ctx->len) {
-		pr_info("btrfsic: file item out of bounce at logical %llu, dev %pg\n",
-		       block_ctx->start, block_ctx->dev->bdev);
-		return -1;
-	}
-
-	btrfsic_read_from_block_data(block_ctx, &file_extent_item,
-		file_extent_item_offset,
-		offsetof(struct btrfs_file_extent_item, disk_num_bytes));
-	if (BTRFS_FILE_EXTENT_REG != file_extent_item.type ||
-	    btrfs_stack_file_extent_disk_bytenr(&file_extent_item) == 0) {
-		if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
-			pr_info("extent_data: type %u, disk_bytenr = %llu\n",
-			       file_extent_item.type,
-			       btrfs_stack_file_extent_disk_bytenr(
-			       &file_extent_item));
-		return 0;
-	}
-
-	if (file_extent_item_offset + sizeof(struct btrfs_file_extent_item) >
-	    block_ctx->len) {
-		pr_info("btrfsic: file item out of bounce at logical %llu, dev %pg\n",
-		       block_ctx->start, block_ctx->dev->bdev);
-		return -1;
-	}
-	btrfsic_read_from_block_data(block_ctx, &file_extent_item,
-				     file_extent_item_offset,
-				     sizeof(struct btrfs_file_extent_item));
-	next_bytenr = btrfs_stack_file_extent_disk_bytenr(&file_extent_item);
-	if (btrfs_stack_file_extent_compression(&file_extent_item) ==
-	    BTRFS_COMPRESS_NONE) {
-		next_bytenr += btrfs_stack_file_extent_offset(&file_extent_item);
-		num_bytes = btrfs_stack_file_extent_num_bytes(&file_extent_item);
-	} else {
-		num_bytes = btrfs_stack_file_extent_disk_num_bytes(&file_extent_item);
-	}
-	generation = btrfs_stack_file_extent_generation(&file_extent_item);
-
-	if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
-		pr_info("extent_data: type %u, disk_bytenr = %llu, offset = %llu, num_bytes = %llu\n",
-		       file_extent_item.type,
-		       btrfs_stack_file_extent_disk_bytenr(&file_extent_item),
-		       btrfs_stack_file_extent_offset(&file_extent_item),
-		       num_bytes);
-	while (num_bytes > 0) {
-		u32 chunk_len;
-		int num_copies;
-		int mirror_num;
-
-		if (num_bytes > state->datablock_size)
-			chunk_len = state->datablock_size;
-		else
-			chunk_len = num_bytes;
-
-		num_copies = btrfs_num_copies(fs_info, next_bytenr,
-					      state->datablock_size);
-		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
-			pr_info("num_copies(log_bytenr=%llu) = %d\n",
-			       next_bytenr, num_copies);
-		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
-			struct btrfsic_block_data_ctx next_block_ctx;
-			struct btrfsic_block *next_block;
-			int block_was_created;
-
-			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
-				pr_info("btrfsic_handle_extent_data(mirror_num=%d)\n",
-					mirror_num);
-			if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
-				pr_info("\tdisk_bytenr = %llu, num_bytes %u\n",
-				       next_bytenr, chunk_len);
-			ret = btrfsic_map_block(state, next_bytenr,
-						chunk_len, &next_block_ctx,
-						mirror_num);
-			if (ret) {
-				pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
-				       next_bytenr, mirror_num);
-				return -1;
-			}
-
-			next_block = btrfsic_block_lookup_or_add(
-					state,
-					&next_block_ctx,
-					"referenced ",
-					0,
-					force_iodone_flag,
-					!force_iodone_flag,
-					mirror_num,
-					&block_was_created);
-			if (NULL == next_block) {
-				btrfsic_release_block_ctx(&next_block_ctx);
-				return -1;
-			}
-			if (!block_was_created) {
-				if ((state->print_mask &
-				     BTRFSIC_PRINT_MASK_VERBOSE) &&
-				    next_block->logical_bytenr != next_bytenr &&
-				    !(!next_block->is_metadata &&
-				      0 == next_block->logical_bytenr)) {
-					pr_info(
-"referenced block @%llu (%pg/%llu/%d) found in hash table, D, bytenr mismatch (!= stored %llu)\n",
-					       next_bytenr,
-					       next_block_ctx.dev->bdev,
-					       next_block_ctx.dev_bytenr,
-					       mirror_num,
-					       next_block->logical_bytenr);
-				}
-				next_block->logical_bytenr = next_bytenr;
-				next_block->mirror_num = mirror_num;
-			}
-
-			l = btrfsic_block_link_lookup_or_add(state,
-							     &next_block_ctx,
-							     next_block, block,
-							     generation);
-			btrfsic_release_block_ctx(&next_block_ctx);
-			if (NULL == l)
-				return -1;
-		}
-
-		next_bytenr += chunk_len;
-		num_bytes -= chunk_len;
-	}
-
-	return 0;
-}
-
-static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
-			     struct btrfsic_block_data_ctx *block_ctx_out,
-			     int mirror_num)
-{
-	struct btrfs_fs_info *fs_info = state->fs_info;
-	int ret;
-	u64 length;
-	struct btrfs_io_context *bioc = NULL;
-	struct btrfs_io_stripe smap, *map;
-	struct btrfs_device *device;
-
-	length = len;
-	ret = btrfs_map_block(fs_info, BTRFS_MAP_READ, bytenr, &length, &bioc,
-			      NULL, &mirror_num, 0);
-	if (ret) {
-		block_ctx_out->start = 0;
-		block_ctx_out->dev_bytenr = 0;
-		block_ctx_out->len = 0;
-		block_ctx_out->dev = NULL;
-		block_ctx_out->datav = NULL;
-		block_ctx_out->pagev = NULL;
-		block_ctx_out->mem_to_free = NULL;
-
-		return ret;
-	}
-
-	if (bioc)
-		map = &bioc->stripes[0];
-	else
-		map = &smap;
-
-	device = map->dev;
-	if (test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state) ||
-	    !device->bdev || !device->name)
-		block_ctx_out->dev = NULL;
-	else
-		block_ctx_out->dev = btrfsic_dev_state_lookup(
-							device->bdev->bd_dev);
-	block_ctx_out->dev_bytenr = map->physical;
-	block_ctx_out->start = bytenr;
-	block_ctx_out->len = len;
-	block_ctx_out->datav = NULL;
-	block_ctx_out->pagev = NULL;
-	block_ctx_out->mem_to_free = NULL;
-
-	kfree(bioc);
-	if (NULL == block_ctx_out->dev) {
-		ret = -ENXIO;
-		pr_info("btrfsic: error, cannot lookup dev (#1)!\n");
-	}
-
-	return ret;
-}
-
-static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
-{
-	if (block_ctx->mem_to_free) {
-		unsigned int num_pages;
-
-		BUG_ON(!block_ctx->datav);
-		BUG_ON(!block_ctx->pagev);
-		num_pages = (block_ctx->len + (u64)PAGE_SIZE - 1) >>
-			    PAGE_SHIFT;
-		/* Pages must be unmapped in reverse order */
-		while (num_pages > 0) {
-			num_pages--;
-			if (block_ctx->datav[num_pages])
-				block_ctx->datav[num_pages] = NULL;
-			if (block_ctx->pagev[num_pages]) {
-				__free_page(block_ctx->pagev[num_pages]);
-				block_ctx->pagev[num_pages] = NULL;
-			}
-		}
-
-		kfree(block_ctx->mem_to_free);
-		block_ctx->mem_to_free = NULL;
-		block_ctx->pagev = NULL;
-		block_ctx->datav = NULL;
-	}
-}
-
-static int btrfsic_read_block(struct btrfsic_state *state,
-			      struct btrfsic_block_data_ctx *block_ctx)
-{
-	unsigned int num_pages;
-	unsigned int i;
-	size_t size;
-	u64 dev_bytenr;
-	int ret;
-
-	BUG_ON(block_ctx->datav);
-	BUG_ON(block_ctx->pagev);
-	BUG_ON(block_ctx->mem_to_free);
-	if (!PAGE_ALIGNED(block_ctx->dev_bytenr)) {
-		pr_info("btrfsic: read_block() with unaligned bytenr %llu\n",
-		       block_ctx->dev_bytenr);
-		return -1;
-	}
-
-	num_pages = (block_ctx->len + (u64)PAGE_SIZE - 1) >>
-		    PAGE_SHIFT;
-	size = sizeof(*block_ctx->datav) + sizeof(*block_ctx->pagev);
-	block_ctx->mem_to_free = kcalloc(num_pages, size, GFP_NOFS);
-	if (!block_ctx->mem_to_free)
-		return -ENOMEM;
-	block_ctx->datav = block_ctx->mem_to_free;
-	block_ctx->pagev = (struct page **)(block_ctx->datav + num_pages);
-	ret = btrfs_alloc_page_array(num_pages, block_ctx->pagev);
-	if (ret)
-		return ret;
-
-	dev_bytenr = block_ctx->dev_bytenr;
-	for (i = 0; i < num_pages;) {
-		struct bio *bio;
-		unsigned int j;
-
-		bio = bio_alloc(block_ctx->dev->bdev, num_pages - i,
-				REQ_OP_READ, GFP_NOFS);
-		bio->bi_iter.bi_sector = dev_bytenr >> SECTOR_SHIFT;
-
-		for (j = i; j < num_pages; j++) {
-			ret = bio_add_page(bio, block_ctx->pagev[j],
-					   PAGE_SIZE, 0);
-			if (PAGE_SIZE != ret)
-				break;
-		}
-		if (j == i) {
-			pr_info("btrfsic: error, failed to add a single page!\n");
-			return -1;
-		}
-		if (submit_bio_wait(bio)) {
-			pr_info("btrfsic: read error at logical %llu dev %pg!\n",
-			       block_ctx->start, block_ctx->dev->bdev);
-			bio_put(bio);
-			return -1;
-		}
-		bio_put(bio);
-		dev_bytenr += (j - i) * PAGE_SIZE;
-		i = j;
-	}
-	for (i = 0; i < num_pages; i++)
-		block_ctx->datav[i] = page_address(block_ctx->pagev[i]);
-
-	return block_ctx->len;
-}
-
-static void btrfsic_dump_database(struct btrfsic_state *state)
-{
-	const struct btrfsic_block *b_all;
-
-	BUG_ON(NULL == state);
-
-	pr_info("all_blocks_list:\n");
-	list_for_each_entry(b_all, &state->all_blocks_list, all_blocks_node) {
-		const struct btrfsic_block_link *l;
-
-		pr_info("%c-block @%llu (%pg/%llu/%d)\n",
-		       btrfsic_get_block_type(state, b_all),
-		       b_all->logical_bytenr, b_all->dev_state->bdev,
-		       b_all->dev_bytenr, b_all->mirror_num);
-
-		list_for_each_entry(l, &b_all->ref_to_list, node_ref_to) {
-			pr_info(
-		" %c @%llu (%pg/%llu/%d) refers %u* to %c @%llu (%pg/%llu/%d)\n",
-			       btrfsic_get_block_type(state, b_all),
-			       b_all->logical_bytenr, b_all->dev_state->bdev,
-			       b_all->dev_bytenr, b_all->mirror_num,
-			       l->ref_cnt,
-			       btrfsic_get_block_type(state, l->block_ref_to),
-			       l->block_ref_to->logical_bytenr,
-			       l->block_ref_to->dev_state->bdev,
-			       l->block_ref_to->dev_bytenr,
-			       l->block_ref_to->mirror_num);
-		}
-
-		list_for_each_entry(l, &b_all->ref_from_list, node_ref_from) {
-			pr_info(
-		" %c @%llu (%pg/%llu/%d) is ref %u* from %c @%llu (%pg/%llu/%d)\n",
-			       btrfsic_get_block_type(state, b_all),
-			       b_all->logical_bytenr, b_all->dev_state->bdev,
-			       b_all->dev_bytenr, b_all->mirror_num,
-			       l->ref_cnt,
-			       btrfsic_get_block_type(state, l->block_ref_from),
-			       l->block_ref_from->logical_bytenr,
-			       l->block_ref_from->dev_state->bdev,
-			       l->block_ref_from->dev_bytenr,
-			       l->block_ref_from->mirror_num);
-		}
-
-		pr_info("\n");
-	}
-}
-
-/*
- * Test whether the disk block contains a tree block (leaf or node)
- * (note that this test fails for the super block)
- */
-static noinline_for_stack int btrfsic_test_for_metadata(
-		struct btrfsic_state *state,
-		char **datav, unsigned int num_pages)
-{
-	struct btrfs_fs_info *fs_info = state->fs_info;
-	SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
-	struct btrfs_header *h;
-	u8 csum[BTRFS_CSUM_SIZE];
-	unsigned int i;
-
-	if (num_pages * PAGE_SIZE < state->metablock_size)
-		return 1; /* not metadata */
-	num_pages = state->metablock_size >> PAGE_SHIFT;
-	h = (struct btrfs_header *)datav[0];
-
-	if (memcmp(h->fsid, fs_info->fs_devices->fsid, BTRFS_FSID_SIZE))
-		return 1;
-
-	shash->tfm = fs_info->csum_shash;
-	crypto_shash_init(shash);
-
-	for (i = 0; i < num_pages; i++) {
-		u8 *data = i ? datav[i] : (datav[i] + BTRFS_CSUM_SIZE);
-		size_t sublen = i ? PAGE_SIZE :
-				    (PAGE_SIZE - BTRFS_CSUM_SIZE);
-
-		crypto_shash_update(shash, data, sublen);
-	}
-	crypto_shash_final(shash, csum);
-	if (memcmp(csum, h->csum, fs_info->csum_size))
-		return 1;
-
-	return 0; /* is metadata */
-}
-
-static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
-					  u64 dev_bytenr, char **mapped_datav,
-					  unsigned int num_pages,
-					  struct bio *bio, int *bio_is_patched,
-					  blk_opf_t submit_bio_bh_rw)
-{
-	int is_metadata;
-	struct btrfsic_block *block;
-	struct btrfsic_block_data_ctx block_ctx;
-	int ret;
-	struct btrfsic_state *state = dev_state->state;
-	struct block_device *bdev = dev_state->bdev;
-	unsigned int processed_len;
-
-	if (NULL != bio_is_patched)
-		*bio_is_patched = 0;
-
-again:
-	if (num_pages == 0)
-		return;
-
-	processed_len = 0;
-	is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_datav,
-						      num_pages));
-
-	block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
-					       &state->block_hashtable);
-	if (NULL != block) {
-		u64 bytenr = 0;
-		struct btrfsic_block_link *l, *tmp;
-
-		if (block->is_superblock) {
-			bytenr = btrfs_super_bytenr((struct btrfs_super_block *)
-						    mapped_datav[0]);
-			if (num_pages * PAGE_SIZE <
-			    BTRFS_SUPER_INFO_SIZE) {
-				pr_info("btrfsic: cannot work with too short bios!\n");
-				return;
-			}
-			is_metadata = 1;
-			BUG_ON(!PAGE_ALIGNED(BTRFS_SUPER_INFO_SIZE));
-			processed_len = BTRFS_SUPER_INFO_SIZE;
-			if (state->print_mask &
-			    BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
-				pr_info("[before new superblock is written]:\n");
-				btrfsic_dump_tree_sub(state, block, 0);
-			}
-		}
-		if (is_metadata) {
-			if (!block->is_superblock) {
-				if (num_pages * PAGE_SIZE <
-				    state->metablock_size) {
-					pr_info("btrfsic: cannot work with too short bios!\n");
-					return;
-				}
-				processed_len = state->metablock_size;
-				bytenr = btrfs_stack_header_bytenr(
-						(struct btrfs_header *)
-						mapped_datav[0]);
-				btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
-							       dev_state,
-							       dev_bytenr);
-			}
-			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE) {
-				if (block->logical_bytenr != bytenr &&
-				    !(!block->is_metadata &&
-				      block->logical_bytenr == 0))
-					pr_info(
-"written block @%llu (%pg/%llu/%d) found in hash table, %c, bytenr mismatch (!= stored %llu)\n",
-					       bytenr, dev_state->bdev,
-					       dev_bytenr,
-					       block->mirror_num,
-					       btrfsic_get_block_type(state,
-								      block),
-					       block->logical_bytenr);
-				else
-					pr_info(
-		"written block @%llu (%pg/%llu/%d) found in hash table, %c\n",
-					       bytenr, dev_state->bdev,
-					       dev_bytenr, block->mirror_num,
-					       btrfsic_get_block_type(state,
-								      block));
-			}
-			block->logical_bytenr = bytenr;
-		} else {
-			if (num_pages * PAGE_SIZE <
-			    state->datablock_size) {
-				pr_info("btrfsic: cannot work with too short bios!\n");
-				return;
-			}
-			processed_len = state->datablock_size;
-			bytenr = block->logical_bytenr;
-			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
-				pr_info(
-		"written block @%llu (%pg/%llu/%d) found in hash table, %c\n",
-				       bytenr, dev_state->bdev, dev_bytenr,
-				       block->mirror_num,
-				       btrfsic_get_block_type(state, block));
-		}
-
-		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
-			pr_info("ref_to_list: %cE, ref_from_list: %cE\n",
-			       list_empty(&block->ref_to_list) ? ' ' : '!',
-			       list_empty(&block->ref_from_list) ? ' ' : '!');
-		if (btrfsic_is_block_ref_by_superblock(state, block, 0)) {
-			pr_info(
-"btrfs: attempt to overwrite %c-block @%llu (%pg/%llu/%d), old(gen=%llu, objectid=%llu, type=%d, offset=%llu), new(gen=%llu), which is referenced by most recent superblock (superblockgen=%llu)!\n",
-			       btrfsic_get_block_type(state, block), bytenr,
-			       dev_state->bdev, dev_bytenr, block->mirror_num,
-			       block->generation,
-			       btrfs_disk_key_objectid(&block->disk_key),
-			       block->disk_key.type,
-			       btrfs_disk_key_offset(&block->disk_key),
-			       btrfs_stack_header_generation(
-				       (struct btrfs_header *) mapped_datav[0]),
-			       state->max_superblock_generation);
-			btrfsic_dump_tree(state);
-		}
-
-		if (!block->is_iodone && !block->never_written) {
-			pr_info(
-"btrfs: attempt to overwrite %c-block @%llu (%pg/%llu/%d), oldgen=%llu, newgen=%llu, which is not yet iodone!\n",
-			       btrfsic_get_block_type(state, block), bytenr,
-			       dev_state->bdev, dev_bytenr, block->mirror_num,
-			       block->generation,
-			       btrfs_stack_header_generation(
-				       (struct btrfs_header *)
-				       mapped_datav[0]));
-			/* it would not be safe to go on */
-			btrfsic_dump_tree(state);
-			goto continue_loop;
-		}
-
-		/*
-		 * Clear all references of this block. Do not free
-		 * the block itself even if is not referenced anymore
-		 * because it still carries valuable information
-		 * like whether it was ever written and IO completed.
-		 */
-		list_for_each_entry_safe(l, tmp, &block->ref_to_list,
-					 node_ref_to) {
-			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
-				btrfsic_print_rem_link(state, l);
-			l->ref_cnt--;
-			if (0 == l->ref_cnt) {
-				list_del(&l->node_ref_to);
-				list_del(&l->node_ref_from);
-				btrfsic_block_link_hashtable_remove(l);
-				btrfsic_block_link_free(l);
-			}
-		}
-
-		block_ctx.dev = dev_state;
-		block_ctx.dev_bytenr = dev_bytenr;
-		block_ctx.start = bytenr;
-		block_ctx.len = processed_len;
-		block_ctx.pagev = NULL;
-		block_ctx.mem_to_free = NULL;
-		block_ctx.datav = mapped_datav;
-
-		if (is_metadata || state->include_extent_data) {
-			block->never_written = 0;
-			block->iodone_w_error = 0;
-			if (NULL != bio) {
-				block->is_iodone = 0;
-				BUG_ON(NULL == bio_is_patched);
-				if (!*bio_is_patched) {
-					block->orig_bio_private =
-					    bio->bi_private;
-					block->orig_bio_end_io =
-					    bio->bi_end_io;
-					block->next_in_same_bio = NULL;
-					bio->bi_private = block;
-					bio->bi_end_io = btrfsic_bio_end_io;
-					*bio_is_patched = 1;
-				} else {
-					struct btrfsic_block *chained_block =
-					    (struct btrfsic_block *)
-					    bio->bi_private;
-
-					BUG_ON(NULL == chained_block);
-					block->orig_bio_private =
-					    chained_block->orig_bio_private;
-					block->orig_bio_end_io =
-					    chained_block->orig_bio_end_io;
-					block->next_in_same_bio = chained_block;
-					bio->bi_private = block;
-				}
-			} else {
-				block->is_iodone = 1;
-				block->orig_bio_private = NULL;
-				block->orig_bio_end_io = NULL;
-				block->next_in_same_bio = NULL;
-			}
-		}
-
-		block->flush_gen = dev_state->last_flush_gen + 1;
-		block->submit_bio_bh_rw = submit_bio_bh_rw;
-		if (is_metadata) {
-			block->logical_bytenr = bytenr;
-			block->is_metadata = 1;
-			if (block->is_superblock) {
-				BUG_ON(PAGE_SIZE !=
-				       BTRFS_SUPER_INFO_SIZE);
-				ret = btrfsic_process_written_superblock(
-						state,
-						block,
-						(struct btrfs_super_block *)
-						mapped_datav[0]);
-				if (state->print_mask &
-				    BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE) {
-					pr_info("[after new superblock is written]:\n");
-					btrfsic_dump_tree_sub(state, block, 0);
-				}
-			} else {
-				block->mirror_num = 0;	/* unknown */
-				ret = btrfsic_process_metablock(
-						state,
-						block,
-						&block_ctx,
-						0, 0);
-			}
-			if (ret)
-				pr_info("btrfsic: btrfsic_process_metablock(root @%llu) failed!\n",
-				       dev_bytenr);
-		} else {
-			block->is_metadata = 0;
-			block->mirror_num = 0;	/* unknown */
-			block->generation = BTRFSIC_GENERATION_UNKNOWN;
-			if (!state->include_extent_data
-			    && list_empty(&block->ref_from_list)) {
-				/*
-				 * disk block is overwritten with extent
-				 * data (not meta data) and we are configured
-				 * to not include extent data: take the
-				 * chance and free the block's memory
-				 */
-				btrfsic_block_hashtable_remove(block);
-				list_del(&block->all_blocks_node);
-				btrfsic_block_free(block);
-			}
-		}
-		btrfsic_release_block_ctx(&block_ctx);
-	} else {
-		/* block has not been found in hash table */
-		u64 bytenr;
-
-		if (!is_metadata) {
-			processed_len = state->datablock_size;
-			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
-				pr_info(
-			"written block (%pg/%llu/?) !found in hash table, D\n",
-				       dev_state->bdev, dev_bytenr);
-			if (!state->include_extent_data) {
-				/* ignore that written D block */
-				goto continue_loop;
-			}
-
-			/* this is getting ugly for the
-			 * include_extent_data case... */
-			bytenr = 0;	/* unknown */
-		} else {
-			processed_len = state->metablock_size;
-			bytenr = btrfs_stack_header_bytenr(
-					(struct btrfs_header *)
-					mapped_datav[0]);
-			btrfsic_cmp_log_and_dev_bytenr(state, bytenr, dev_state,
-						       dev_bytenr);
-			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
-				pr_info(
-			"written block @%llu (%pg/%llu/?) !found in hash table, M\n",
-				       bytenr, dev_state->bdev, dev_bytenr);
-		}
-
-		block_ctx.dev = dev_state;
-		block_ctx.dev_bytenr = dev_bytenr;
-		block_ctx.start = bytenr;
-		block_ctx.len = processed_len;
-		block_ctx.pagev = NULL;
-		block_ctx.mem_to_free = NULL;
-		block_ctx.datav = mapped_datav;
-
-		block = btrfsic_block_alloc();
-		if (NULL == block) {
-			btrfsic_release_block_ctx(&block_ctx);
-			goto continue_loop;
-		}
-		block->dev_state = dev_state;
-		block->dev_bytenr = dev_bytenr;
-		block->logical_bytenr = bytenr;
-		block->is_metadata = is_metadata;
-		block->never_written = 0;
-		block->iodone_w_error = 0;
-		block->mirror_num = 0;	/* unknown */
-		block->flush_gen = dev_state->last_flush_gen + 1;
-		block->submit_bio_bh_rw = submit_bio_bh_rw;
-		if (NULL != bio) {
-			block->is_iodone = 0;
-			BUG_ON(NULL == bio_is_patched);
-			if (!*bio_is_patched) {
-				block->orig_bio_private = bio->bi_private;
-				block->orig_bio_end_io = bio->bi_end_io;
-				block->next_in_same_bio = NULL;
-				bio->bi_private = block;
-				bio->bi_end_io = btrfsic_bio_end_io;
-				*bio_is_patched = 1;
-			} else {
-				struct btrfsic_block *chained_block =
-				    (struct btrfsic_block *)
-				    bio->bi_private;
-
-				BUG_ON(NULL == chained_block);
-				block->orig_bio_private =
-				    chained_block->orig_bio_private;
-				block->orig_bio_end_io =
-				    chained_block->orig_bio_end_io;
-				block->next_in_same_bio = chained_block;
-				bio->bi_private = block;
-			}
-		} else {
-			block->is_iodone = 1;
-			block->orig_bio_private = NULL;
-			block->orig_bio_end_io = NULL;
-			block->next_in_same_bio = NULL;
-		}
-		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
-			pr_info("new written %c-block @%llu (%pg/%llu/%d)\n",
-			       is_metadata ? 'M' : 'D',
-			       block->logical_bytenr, block->dev_state->bdev,
-			       block->dev_bytenr, block->mirror_num);
-		list_add(&block->all_blocks_node, &state->all_blocks_list);
-		btrfsic_block_hashtable_add(block, &state->block_hashtable);
-
-		if (is_metadata) {
-			ret = btrfsic_process_metablock(state, block,
-							&block_ctx, 0, 0);
-			if (ret)
-				pr_info("btrfsic: process_metablock(root @%llu) failed!\n",
-				       dev_bytenr);
-		}
-		btrfsic_release_block_ctx(&block_ctx);
-	}
-
-continue_loop:
-	BUG_ON(!processed_len);
-	dev_bytenr += processed_len;
-	mapped_datav += processed_len >> PAGE_SHIFT;
-	num_pages -= processed_len >> PAGE_SHIFT;
-	goto again;
-}
-
-static void btrfsic_bio_end_io(struct bio *bp)
-{
-	struct btrfsic_block *block = bp->bi_private;
-	int iodone_w_error;
-
-	/* mutex is not held! This is not save if IO is not yet completed
-	 * on umount */
-	iodone_w_error = 0;
-	if (bp->bi_status)
-		iodone_w_error = 1;
-
-	BUG_ON(NULL == block);
-	bp->bi_private = block->orig_bio_private;
-	bp->bi_end_io = block->orig_bio_end_io;
-
-	do {
-		struct btrfsic_block *next_block;
-		struct btrfsic_dev_state *const dev_state = block->dev_state;
-
-		if ((dev_state->state->print_mask &
-		     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
-			pr_info("bio_end_io(err=%d) for %c @%llu (%pg/%llu/%d)\n",
-			       bp->bi_status,
-			       btrfsic_get_block_type(dev_state->state, block),
-			       block->logical_bytenr, dev_state->bdev,
-			       block->dev_bytenr, block->mirror_num);
-		next_block = block->next_in_same_bio;
-		block->iodone_w_error = iodone_w_error;
-		if (block->submit_bio_bh_rw & REQ_PREFLUSH) {
-			dev_state->last_flush_gen++;
-			if ((dev_state->state->print_mask &
-			     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
-				pr_info("bio_end_io() new %pg flush_gen=%llu\n",
-				       dev_state->bdev,
-				       dev_state->last_flush_gen);
-		}
-		if (block->submit_bio_bh_rw & REQ_FUA)
-			block->flush_gen = 0; /* FUA completed means block is
-					       * on disk */
-		block->is_iodone = 1; /* for FLUSH, this releases the block */
-		block = next_block;
-	} while (NULL != block);
-
-	bp->bi_end_io(bp);
-}
-
-static int btrfsic_process_written_superblock(
-		struct btrfsic_state *state,
-		struct btrfsic_block *const superblock,
-		struct btrfs_super_block *const super_hdr)
-{
-	struct btrfs_fs_info *fs_info = state->fs_info;
-	int pass;
-
-	superblock->generation = btrfs_super_generation(super_hdr);
-	if (!(superblock->generation > state->max_superblock_generation ||
-	      0 == state->max_superblock_generation)) {
-		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
-			pr_info(
-	"btrfsic: superblock @%llu (%pg/%llu/%d) with old gen %llu <= %llu\n",
-			       superblock->logical_bytenr,
-			       superblock->dev_state->bdev,
-			       superblock->dev_bytenr, superblock->mirror_num,
-			       btrfs_super_generation(super_hdr),
-			       state->max_superblock_generation);
-	} else {
-		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
-			pr_info(
-	"btrfsic: got new superblock @%llu (%pg/%llu/%d) with new gen %llu > %llu\n",
-			       superblock->logical_bytenr,
-			       superblock->dev_state->bdev,
-			       superblock->dev_bytenr, superblock->mirror_num,
-			       btrfs_super_generation(super_hdr),
-			       state->max_superblock_generation);
-
-		state->max_superblock_generation =
-		    btrfs_super_generation(super_hdr);
-		state->latest_superblock = superblock;
-	}
-
-	for (pass = 0; pass < 3; pass++) {
-		int ret;
-		u64 next_bytenr;
-		struct btrfsic_block *next_block;
-		struct btrfsic_block_data_ctx tmp_next_block_ctx;
-		struct btrfsic_block_link *l;
-		int num_copies;
-		int mirror_num;
-		const char *additional_string = NULL;
-		struct btrfs_disk_key tmp_disk_key = {0};
-
-		btrfs_set_disk_key_objectid(&tmp_disk_key,
-					    BTRFS_ROOT_ITEM_KEY);
-		btrfs_set_disk_key_objectid(&tmp_disk_key, 0);
-
-		switch (pass) {
-		case 0:
-			btrfs_set_disk_key_objectid(&tmp_disk_key,
-						    BTRFS_ROOT_TREE_OBJECTID);
-			additional_string = "root ";
-			next_bytenr = btrfs_super_root(super_hdr);
-			if (state->print_mask &
-			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
-				pr_info("root@%llu\n", next_bytenr);
-			break;
-		case 1:
-			btrfs_set_disk_key_objectid(&tmp_disk_key,
-						    BTRFS_CHUNK_TREE_OBJECTID);
-			additional_string = "chunk ";
-			next_bytenr = btrfs_super_chunk_root(super_hdr);
-			if (state->print_mask &
-			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
-				pr_info("chunk@%llu\n", next_bytenr);
-			break;
-		case 2:
-			btrfs_set_disk_key_objectid(&tmp_disk_key,
-						    BTRFS_TREE_LOG_OBJECTID);
-			additional_string = "log ";
-			next_bytenr = btrfs_super_log_root(super_hdr);
-			if (0 == next_bytenr)
-				continue;
-			if (state->print_mask &
-			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
-				pr_info("log@%llu\n", next_bytenr);
-			break;
-		}
-
-		num_copies = btrfs_num_copies(fs_info, next_bytenr,
-					      BTRFS_SUPER_INFO_SIZE);
-		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
-			pr_info("num_copies(log_bytenr=%llu) = %d\n",
-			       next_bytenr, num_copies);
-		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
-			int was_created;
-
-			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
-				pr_info("btrfsic_process_written_superblock(mirror_num=%d)\n", mirror_num);
-			ret = btrfsic_map_block(state, next_bytenr,
-						BTRFS_SUPER_INFO_SIZE,
-						&tmp_next_block_ctx,
-						mirror_num);
-			if (ret) {
-				pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
-				       next_bytenr, mirror_num);
-				return -1;
-			}
-
-			next_block = btrfsic_block_lookup_or_add(
-					state,
-					&tmp_next_block_ctx,
-					additional_string,
-					1, 0, 1,
-					mirror_num,
-					&was_created);
-			if (NULL == next_block) {
-				btrfsic_release_block_ctx(&tmp_next_block_ctx);
-				return -1;
-			}
-
-			next_block->disk_key = tmp_disk_key;
-			if (was_created)
-				next_block->generation =
-				    BTRFSIC_GENERATION_UNKNOWN;
-			l = btrfsic_block_link_lookup_or_add(
-					state,
-					&tmp_next_block_ctx,
-					next_block,
-					superblock,
-					BTRFSIC_GENERATION_UNKNOWN);
-			btrfsic_release_block_ctx(&tmp_next_block_ctx);
-			if (NULL == l)
-				return -1;
-		}
-	}
-
-	if (WARN_ON(-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)))
-		btrfsic_dump_tree(state);
-
-	return 0;
-}
-
-static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
-					struct btrfsic_block *const block,
-					int recursion_level)
-{
-	const struct btrfsic_block_link *l;
-	int ret = 0;
-
-	if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
-		/*
-		 * Note that this situation can happen and does not
-		 * indicate an error in regular cases. It happens
-		 * when disk blocks are freed and later reused.
-		 * The check-integrity module is not aware of any
-		 * block free operations, it just recognizes block
-		 * write operations. Therefore it keeps the linkage
-		 * information for a block until a block is
-		 * rewritten. This can temporarily cause incorrect
-		 * and even circular linkage information. This
-		 * causes no harm unless such blocks are referenced
-		 * by the most recent super block.
-		 */
-		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
-			pr_info("btrfsic: abort cyclic linkage (case 1).\n");
-
-		return ret;
-	}
-
-	/*
-	 * This algorithm is recursive because the amount of used stack
-	 * space is very small and the max recursion depth is limited.
-	 */
-	list_for_each_entry(l, &block->ref_to_list, node_ref_to) {
-		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
-			pr_info(
-		"rl=%d, %c @%llu (%pg/%llu/%d) %u* refers to %c @%llu (%pg/%llu/%d)\n",
-			       recursion_level,
-			       btrfsic_get_block_type(state, block),
-			       block->logical_bytenr, block->dev_state->bdev,
-			       block->dev_bytenr, block->mirror_num,
-			       l->ref_cnt,
-			       btrfsic_get_block_type(state, l->block_ref_to),
-			       l->block_ref_to->logical_bytenr,
-			       l->block_ref_to->dev_state->bdev,
-			       l->block_ref_to->dev_bytenr,
-			       l->block_ref_to->mirror_num);
-		if (l->block_ref_to->never_written) {
-			pr_info(
-"btrfs: attempt to write superblock which references block %c @%llu (%pg/%llu/%d) which is never written!\n",
-			       btrfsic_get_block_type(state, l->block_ref_to),
-			       l->block_ref_to->logical_bytenr,
-			       l->block_ref_to->dev_state->bdev,
-			       l->block_ref_to->dev_bytenr,
-			       l->block_ref_to->mirror_num);
-			ret = -1;
-		} else if (!l->block_ref_to->is_iodone) {
-			pr_info(
-"btrfs: attempt to write superblock which references block %c @%llu (%pg/%llu/%d) which is not yet iodone!\n",
-			       btrfsic_get_block_type(state, l->block_ref_to),
-			       l->block_ref_to->logical_bytenr,
-			       l->block_ref_to->dev_state->bdev,
-			       l->block_ref_to->dev_bytenr,
-			       l->block_ref_to->mirror_num);
-			ret = -1;
-		} else if (l->block_ref_to->iodone_w_error) {
-			pr_info(
-"btrfs: attempt to write superblock which references block %c @%llu (%pg/%llu/%d) which has write error!\n",
-			       btrfsic_get_block_type(state, l->block_ref_to),
-			       l->block_ref_to->logical_bytenr,
-			       l->block_ref_to->dev_state->bdev,
-			       l->block_ref_to->dev_bytenr,
-			       l->block_ref_to->mirror_num);
-			ret = -1;
-		} else if (l->parent_generation !=
-			   l->block_ref_to->generation &&
-			   BTRFSIC_GENERATION_UNKNOWN !=
-			   l->parent_generation &&
-			   BTRFSIC_GENERATION_UNKNOWN !=
-			   l->block_ref_to->generation) {
-			pr_info(
-"btrfs: attempt to write superblock which references block %c @%llu (%pg/%llu/%d) with generation %llu != parent generation %llu!\n",
-			       btrfsic_get_block_type(state, l->block_ref_to),
-			       l->block_ref_to->logical_bytenr,
-			       l->block_ref_to->dev_state->bdev,
-			       l->block_ref_to->dev_bytenr,
-			       l->block_ref_to->mirror_num,
-			       l->block_ref_to->generation,
-			       l->parent_generation);
-			ret = -1;
-		} else if (l->block_ref_to->flush_gen >
-			   l->block_ref_to->dev_state->last_flush_gen) {
-			pr_info(
-"btrfs: attempt to write superblock which references block %c @%llu (%pg/%llu/%d) which is not flushed out of disk's write cache (block flush_gen=%llu, dev->flush_gen=%llu)!\n",
-			       btrfsic_get_block_type(state, l->block_ref_to),
-			       l->block_ref_to->logical_bytenr,
-			       l->block_ref_to->dev_state->bdev,
-			       l->block_ref_to->dev_bytenr,
-			       l->block_ref_to->mirror_num, block->flush_gen,
-			       l->block_ref_to->dev_state->last_flush_gen);
-			ret = -1;
-		} else if (-1 == btrfsic_check_all_ref_blocks(state,
-							      l->block_ref_to,
-							      recursion_level +
-							      1)) {
-			ret = -1;
-		}
-	}
-
-	return ret;
-}
-
-static int btrfsic_is_block_ref_by_superblock(
-		const struct btrfsic_state *state,
-		const struct btrfsic_block *block,
-		int recursion_level)
-{
-	const struct btrfsic_block_link *l;
-
-	if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
-		/* refer to comment at "abort cyclic linkage (case 1)" */
-		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
-			pr_info("btrfsic: abort cyclic linkage (case 2).\n");
-
-		return 0;
-	}
-
-	/*
-	 * This algorithm is recursive because the amount of used stack space
-	 * is very small and the max recursion depth is limited.
-	 */
-	list_for_each_entry(l, &block->ref_from_list, node_ref_from) {
-		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
-			pr_info(
-	"rl=%d, %c @%llu (%pg/%llu/%d) is ref %u* from %c @%llu (%pg/%llu/%d)\n",
-			       recursion_level,
-			       btrfsic_get_block_type(state, block),
-			       block->logical_bytenr, block->dev_state->bdev,
-			       block->dev_bytenr, block->mirror_num,
-			       l->ref_cnt,
-			       btrfsic_get_block_type(state, l->block_ref_from),
-			       l->block_ref_from->logical_bytenr,
-			       l->block_ref_from->dev_state->bdev,
-			       l->block_ref_from->dev_bytenr,
-			       l->block_ref_from->mirror_num);
-		if (l->block_ref_from->is_superblock &&
-		    state->latest_superblock->dev_bytenr ==
-		    l->block_ref_from->dev_bytenr &&
-		    state->latest_superblock->dev_state->bdev ==
-		    l->block_ref_from->dev_state->bdev)
-			return 1;
-		else if (btrfsic_is_block_ref_by_superblock(state,
-							    l->block_ref_from,
-							    recursion_level +
-							    1))
-			return 1;
-	}
-
-	return 0;
-}
-
-static void btrfsic_print_add_link(const struct btrfsic_state *state,
-				   const struct btrfsic_block_link *l)
-{
-	pr_info("add %u* link from %c @%llu (%pg/%llu/%d) to %c @%llu (%pg/%llu/%d)\n",
-	       l->ref_cnt,
-	       btrfsic_get_block_type(state, l->block_ref_from),
-	       l->block_ref_from->logical_bytenr,
-	       l->block_ref_from->dev_state->bdev,
-	       l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
-	       btrfsic_get_block_type(state, l->block_ref_to),
-	       l->block_ref_to->logical_bytenr,
-	       l->block_ref_to->dev_state->bdev, l->block_ref_to->dev_bytenr,
-	       l->block_ref_to->mirror_num);
-}
-
-static void btrfsic_print_rem_link(const struct btrfsic_state *state,
-				   const struct btrfsic_block_link *l)
-{
-	pr_info("rem %u* link from %c @%llu (%pg/%llu/%d) to %c @%llu (%pg/%llu/%d)\n",
-	       l->ref_cnt,
-	       btrfsic_get_block_type(state, l->block_ref_from),
-	       l->block_ref_from->logical_bytenr,
-	       l->block_ref_from->dev_state->bdev,
-	       l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
-	       btrfsic_get_block_type(state, l->block_ref_to),
-	       l->block_ref_to->logical_bytenr,
-	       l->block_ref_to->dev_state->bdev, l->block_ref_to->dev_bytenr,
-	       l->block_ref_to->mirror_num);
-}
-
-static char btrfsic_get_block_type(const struct btrfsic_state *state,
-				   const struct btrfsic_block *block)
-{
-	if (block->is_superblock &&
-	    state->latest_superblock->dev_bytenr == block->dev_bytenr &&
-	    state->latest_superblock->dev_state->bdev == block->dev_state->bdev)
-		return 'S';
-	else if (block->is_superblock)
-		return 's';
-	else if (block->is_metadata)
-		return 'M';
-	else
-		return 'D';
-}
-
-static void btrfsic_dump_tree(const struct btrfsic_state *state)
-{
-	btrfsic_dump_tree_sub(state, state->latest_superblock, 0);
-}
-
-static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
-				  const struct btrfsic_block *block,
-				  int indent_level)
-{
-	const struct btrfsic_block_link *l;
-	int indent_add;
-	static char buf[80];
-	int cursor_position;
-
-	/*
-	 * Should better fill an on-stack buffer with a complete line and
-	 * dump it at once when it is time to print a newline character.
-	 */
-
-	/*
-	 * This algorithm is recursive because the amount of used stack space
-	 * is very small and the max recursion depth is limited.
-	 */
-	indent_add = sprintf(buf, "%c-%llu(%pg/%llu/%u)",
-			     btrfsic_get_block_type(state, block),
-			     block->logical_bytenr, block->dev_state->bdev,
-			     block->dev_bytenr, block->mirror_num);
-	if (indent_level + indent_add > BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
-		printk("[...]\n");
-		return;
-	}
-	printk(buf);
-	indent_level += indent_add;
-	if (list_empty(&block->ref_to_list)) {
-		printk("\n");
-		return;
-	}
-	if (block->mirror_num > 1 &&
-	    !(state->print_mask & BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS)) {
-		printk(" [...]\n");
-		return;
-	}
-
-	cursor_position = indent_level;
-	list_for_each_entry(l, &block->ref_to_list, node_ref_to) {
-		while (cursor_position < indent_level) {
-			printk(" ");
-			cursor_position++;
-		}
-		if (l->ref_cnt > 1)
-			indent_add = sprintf(buf, " %d*--> ", l->ref_cnt);
-		else
-			indent_add = sprintf(buf, " --> ");
-		if (indent_level + indent_add >
-		    BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
-			printk("[...]\n");
-			cursor_position = 0;
-			continue;
-		}
-
-		printk(buf);
-
-		btrfsic_dump_tree_sub(state, l->block_ref_to,
-				      indent_level + indent_add);
-		cursor_position = 0;
-	}
-}
-
-static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
-		struct btrfsic_state *state,
-		struct btrfsic_block_data_ctx *next_block_ctx,
-		struct btrfsic_block *next_block,
-		struct btrfsic_block *from_block,
-		u64 parent_generation)
-{
-	struct btrfsic_block_link *l;
-
-	l = btrfsic_block_link_hashtable_lookup(next_block_ctx->dev->bdev,
-						next_block_ctx->dev_bytenr,
-						from_block->dev_state->bdev,
-						from_block->dev_bytenr,
-						&state->block_link_hashtable);
-	if (NULL == l) {
-		l = btrfsic_block_link_alloc();
-		if (!l)
-			return NULL;
-
-		l->block_ref_to = next_block;
-		l->block_ref_from = from_block;
-		l->ref_cnt = 1;
-		l->parent_generation = parent_generation;
-
-		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
-			btrfsic_print_add_link(state, l);
-
-		list_add(&l->node_ref_to, &from_block->ref_to_list);
-		list_add(&l->node_ref_from, &next_block->ref_from_list);
-
-		btrfsic_block_link_hashtable_add(l,
-						 &state->block_link_hashtable);
-	} else {
-		l->ref_cnt++;
-		l->parent_generation = parent_generation;
-		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
-			btrfsic_print_add_link(state, l);
-	}
-
-	return l;
-}
-
-static struct btrfsic_block *btrfsic_block_lookup_or_add(
-		struct btrfsic_state *state,
-		struct btrfsic_block_data_ctx *block_ctx,
-		const char *additional_string,
-		int is_metadata,
-		int is_iodone,
-		int never_written,
-		int mirror_num,
-		int *was_created)
-{
-	struct btrfsic_block *block;
-
-	block = btrfsic_block_hashtable_lookup(block_ctx->dev->bdev,
-					       block_ctx->dev_bytenr,
-					       &state->block_hashtable);
-	if (NULL == block) {
-		struct btrfsic_dev_state *dev_state;
-
-		block = btrfsic_block_alloc();
-		if (!block)
-			return NULL;
-
-		dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev->bd_dev);
-		if (NULL == dev_state) {
-			pr_info("btrfsic: error, lookup dev_state failed!\n");
-			btrfsic_block_free(block);
-			return NULL;
-		}
-		block->dev_state = dev_state;
-		block->dev_bytenr = block_ctx->dev_bytenr;
-		block->logical_bytenr = block_ctx->start;
-		block->is_metadata = is_metadata;
-		block->is_iodone = is_iodone;
-		block->never_written = never_written;
-		block->mirror_num = mirror_num;
-		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
-			pr_info("New %s%c-block @%llu (%pg/%llu/%d)\n",
-			       additional_string,
-			       btrfsic_get_block_type(state, block),
-			       block->logical_bytenr, dev_state->bdev,
-			       block->dev_bytenr, mirror_num);
-		list_add(&block->all_blocks_node, &state->all_blocks_list);
-		btrfsic_block_hashtable_add(block, &state->block_hashtable);
-		if (NULL != was_created)
-			*was_created = 1;
-	} else {
-		if (NULL != was_created)
-			*was_created = 0;
-	}
-
-	return block;
-}
-
-static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
-					   u64 bytenr,
-					   struct btrfsic_dev_state *dev_state,
-					   u64 dev_bytenr)
-{
-	struct btrfs_fs_info *fs_info = state->fs_info;
-	struct btrfsic_block_data_ctx block_ctx;
-	int num_copies;
-	int mirror_num;
-	int match = 0;
-	int ret;
-
-	num_copies = btrfs_num_copies(fs_info, bytenr, state->metablock_size);
-
-	for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
-		ret = btrfsic_map_block(state, bytenr, state->metablock_size,
-					&block_ctx, mirror_num);
-		if (ret) {
-			pr_info("btrfsic: btrfsic_map_block(logical @%llu, mirror %d) failed!\n",
-			       bytenr, mirror_num);
-			continue;
-		}
-
-		if (dev_state->bdev == block_ctx.dev->bdev &&
-		    dev_bytenr == block_ctx.dev_bytenr) {
-			match++;
-			btrfsic_release_block_ctx(&block_ctx);
-			break;
-		}
-		btrfsic_release_block_ctx(&block_ctx);
-	}
-
-	if (WARN_ON(!match)) {
-		pr_info(
-"btrfs: attempt to write M-block which contains logical bytenr that doesn't map to dev+physical bytenr of submit_bio, buffer->log_bytenr=%llu, submit_bio(bdev=%pg, phys_bytenr=%llu)!\n",
-		       bytenr, dev_state->bdev, dev_bytenr);
-		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
-			ret = btrfsic_map_block(state, bytenr,
-						state->metablock_size,
-						&block_ctx, mirror_num);
-			if (ret)
-				continue;
-
-			pr_info("read logical bytenr @%llu maps to (%pg/%llu/%d)\n",
-			       bytenr, block_ctx.dev->bdev,
-			       block_ctx.dev_bytenr, mirror_num);
-		}
-	}
-}
-
-static struct btrfsic_dev_state *btrfsic_dev_state_lookup(dev_t dev)
-{
-	return btrfsic_dev_state_hashtable_lookup(dev,
-						  &btrfsic_dev_state_hashtable);
-}
-
-static void btrfsic_check_write_bio(struct bio *bio, struct btrfsic_dev_state *dev_state)
-{
-	unsigned int segs = bio_segments(bio);
-	u64 dev_bytenr = 512 * bio->bi_iter.bi_sector;
-	u64 cur_bytenr = dev_bytenr;
-	struct bvec_iter iter;
-	struct bio_vec bvec;
-	char **mapped_datav;
-	int bio_is_patched = 0;
-	int i = 0;
-
-	if (dev_state->state->print_mask & BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
-		pr_info(
-"submit_bio(rw=%d,0x%x, bi_vcnt=%u, bi_sector=%llu (bytenr %llu), bi_bdev=%p)\n",
-		       bio_op(bio), bio->bi_opf, segs,
-		       bio->bi_iter.bi_sector, dev_bytenr, bio->bi_bdev);
-
-	mapped_datav = kmalloc_array(segs, sizeof(*mapped_datav), GFP_NOFS);
-	if (!mapped_datav)
-		return;
-
-	bio_for_each_segment(bvec, bio, iter) {
-		BUG_ON(bvec.bv_len != PAGE_SIZE);
-		mapped_datav[i] = page_address(bvec.bv_page);
-		i++;
-
-		if (dev_state->state->print_mask &
-		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE)
-			pr_info("#%u: bytenr=%llu, len=%u, offset=%u\n",
-			       i, cur_bytenr, bvec.bv_len, bvec.bv_offset);
-		cur_bytenr += bvec.bv_len;
-	}
-
-	btrfsic_process_written_block(dev_state, dev_bytenr, mapped_datav, segs,
-				      bio, &bio_is_patched, bio->bi_opf);
-	kfree(mapped_datav);
-}
-
-static void btrfsic_check_flush_bio(struct bio *bio, struct btrfsic_dev_state *dev_state)
-{
-	if (dev_state->state->print_mask & BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
-		pr_info("submit_bio(rw=%d,0x%x FLUSH, bdev=%p)\n",
-		       bio_op(bio), bio->bi_opf, bio->bi_bdev);
-
-	if (dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
-		struct btrfsic_block *const block =
-			&dev_state->dummy_block_for_bio_bh_flush;
-
-		block->is_iodone = 0;
-		block->never_written = 0;
-		block->iodone_w_error = 0;
-		block->flush_gen = dev_state->last_flush_gen + 1;
-		block->submit_bio_bh_rw = bio->bi_opf;
-		block->orig_bio_private = bio->bi_private;
-		block->orig_bio_end_io = bio->bi_end_io;
-		block->next_in_same_bio = NULL;
-		bio->bi_private = block;
-		bio->bi_end_io = btrfsic_bio_end_io;
-	} else if ((dev_state->state->print_mask &
-		   (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
-		    BTRFSIC_PRINT_MASK_VERBOSE))) {
-		pr_info(
-"btrfsic_submit_bio(%pg) with FLUSH but dummy block already in use (ignored)!\n",
-		       dev_state->bdev);
-	}
-}
-
-void btrfsic_check_bio(struct bio *bio)
-{
-	struct btrfsic_dev_state *dev_state;
-
-	if (!btrfsic_is_initialized)
-		return;
-
-	/*
-	 * We can be called before btrfsic_mount, so there might not be a
-	 * dev_state.
-	 */
-	dev_state = btrfsic_dev_state_lookup(bio->bi_bdev->bd_dev);
-	mutex_lock(&btrfsic_mutex);
-	if (dev_state) {
-		if (bio_op(bio) == REQ_OP_WRITE && bio_has_data(bio))
-			btrfsic_check_write_bio(bio, dev_state);
-		else if (bio->bi_opf & REQ_PREFLUSH)
-			btrfsic_check_flush_bio(bio, dev_state);
-	}
-	mutex_unlock(&btrfsic_mutex);
-}
-
-int btrfsic_mount(struct btrfs_fs_info *fs_info,
-		  struct btrfs_fs_devices *fs_devices,
-		  int including_extent_data, u32 print_mask)
-{
-	int ret;
-	struct btrfsic_state *state;
-	struct list_head *dev_head = &fs_devices->devices;
-	struct btrfs_device *device;
-
-	if (!PAGE_ALIGNED(fs_info->nodesize)) {
-		pr_info("btrfsic: cannot handle nodesize %d not being a multiple of PAGE_SIZE %ld!\n",
-		       fs_info->nodesize, PAGE_SIZE);
-		return -1;
-	}
-	if (!PAGE_ALIGNED(fs_info->sectorsize)) {
-		pr_info("btrfsic: cannot handle sectorsize %d not being a multiple of PAGE_SIZE %ld!\n",
-		       fs_info->sectorsize, PAGE_SIZE);
-		return -1;
-	}
-	state = kvzalloc(sizeof(*state), GFP_KERNEL);
-	if (!state)
-		return -ENOMEM;
-
-	if (!btrfsic_is_initialized) {
-		mutex_init(&btrfsic_mutex);
-		btrfsic_dev_state_hashtable_init(&btrfsic_dev_state_hashtable);
-		btrfsic_is_initialized = 1;
-	}
-	mutex_lock(&btrfsic_mutex);
-	state->fs_info = fs_info;
-	state->print_mask = print_mask;
-	state->include_extent_data = including_extent_data;
-	state->metablock_size = fs_info->nodesize;
-	state->datablock_size = fs_info->sectorsize;
-	INIT_LIST_HEAD(&state->all_blocks_list);
-	btrfsic_block_hashtable_init(&state->block_hashtable);
-	btrfsic_block_link_hashtable_init(&state->block_link_hashtable);
-	state->max_superblock_generation = 0;
-	state->latest_superblock = NULL;
-
-	list_for_each_entry(device, dev_head, dev_list) {
-		struct btrfsic_dev_state *ds;
-
-		if (!device->bdev || !device->name)
-			continue;
-
-		ds = btrfsic_dev_state_alloc();
-		if (NULL == ds) {
-			mutex_unlock(&btrfsic_mutex);
-			return -ENOMEM;
-		}
-		ds->bdev = device->bdev;
-		ds->state = state;
-		btrfsic_dev_state_hashtable_add(ds,
-						&btrfsic_dev_state_hashtable);
-	}
-
-	ret = btrfsic_process_superblock(state, fs_devices);
-	if (0 != ret) {
-		mutex_unlock(&btrfsic_mutex);
-		btrfsic_unmount(fs_devices);
-		return ret;
-	}
-
-	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_DATABASE)
-		btrfsic_dump_database(state);
-	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_TREE)
-		btrfsic_dump_tree(state);
-
-	mutex_unlock(&btrfsic_mutex);
-	return 0;
-}
-
-void btrfsic_unmount(struct btrfs_fs_devices *fs_devices)
-{
-	struct btrfsic_block *b_all, *tmp_all;
-	struct btrfsic_state *state;
-	struct list_head *dev_head = &fs_devices->devices;
-	struct btrfs_device *device;
-
-	if (!btrfsic_is_initialized)
-		return;
-
-	mutex_lock(&btrfsic_mutex);
-
-	state = NULL;
-	list_for_each_entry(device, dev_head, dev_list) {
-		struct btrfsic_dev_state *ds;
-
-		if (!device->bdev || !device->name)
-			continue;
-
-		ds = btrfsic_dev_state_hashtable_lookup(
-				device->bdev->bd_dev,
-				&btrfsic_dev_state_hashtable);
-		if (NULL != ds) {
-			state = ds->state;
-			btrfsic_dev_state_hashtable_remove(ds);
-			btrfsic_dev_state_free(ds);
-		}
-	}
-
-	if (NULL == state) {
-		pr_info("btrfsic: error, cannot find state information on umount!\n");
-		mutex_unlock(&btrfsic_mutex);
-		return;
-	}
-
-	/*
-	 * Don't care about keeping the lists' state up to date,
-	 * just free all memory that was allocated dynamically.
-	 * Free the blocks and the block_links.
-	 */
-	list_for_each_entry_safe(b_all, tmp_all, &state->all_blocks_list,
-				 all_blocks_node) {
-		struct btrfsic_block_link *l, *tmp;
-
-		list_for_each_entry_safe(l, tmp, &b_all->ref_to_list,
-					 node_ref_to) {
-			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
-				btrfsic_print_rem_link(state, l);
-
-			l->ref_cnt--;
-			if (0 == l->ref_cnt)
-				btrfsic_block_link_free(l);
-		}
-
-		if (b_all->is_iodone || b_all->never_written)
-			btrfsic_block_free(b_all);
-		else
-			pr_info(
-"btrfs: attempt to free %c-block @%llu (%pg/%llu/%d) on umount which is not yet iodone!\n",
-			       btrfsic_get_block_type(state, b_all),
-			       b_all->logical_bytenr, b_all->dev_state->bdev,
-			       b_all->dev_bytenr, b_all->mirror_num);
-	}
-
-	mutex_unlock(&btrfsic_mutex);
-
-	kvfree(state);
-}