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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (C) STRATO AG 2011.  All rights reserved.
   4 */
   5
   6/*
   7 * This module can be used to catch cases when the btrfs kernel
   8 * code executes write requests to the disk that bring the file
   9 * system in an inconsistent state. In such a state, a power-loss
  10 * or kernel panic event would cause that the data on disk is
  11 * lost or at least damaged.
  12 *
  13 * Code is added that examines all block write requests during
  14 * runtime (including writes of the super block). Three rules
  15 * are verified and an error is printed on violation of the
  16 * rules:
  17 * 1. It is not allowed to write a disk block which is
  18 *    currently referenced by the super block (either directly
  19 *    or indirectly).
  20 * 2. When a super block is written, it is verified that all
  21 *    referenced (directly or indirectly) blocks fulfill the
  22 *    following requirements:
  23 *    2a. All referenced blocks have either been present when
  24 *        the file system was mounted, (i.e., they have been
  25 *        referenced by the super block) or they have been
  26 *        written since then and the write completion callback
  27 *        was called and no write error was indicated and a
  28 *        FLUSH request to the device where these blocks are
  29 *        located was received and completed.
  30 *    2b. All referenced blocks need to have a generation
  31 *        number which is equal to the parent's number.
  32 *
  33 * One issue that was found using this module was that the log
  34 * tree on disk became temporarily corrupted because disk blocks
  35 * that had been in use for the log tree had been freed and
  36 * reused too early, while being referenced by the written super
  37 * block.
  38 *
  39 * The search term in the kernel log that can be used to filter
  40 * on the existence of detected integrity issues is
  41 * "btrfs: attempt".
  42 *
  43 * The integrity check is enabled via mount options. These
  44 * mount options are only supported if the integrity check
  45 * tool is compiled by defining BTRFS_FS_CHECK_INTEGRITY.
  46 *
  47 * Example #1, apply integrity checks to all metadata:
  48 * mount /dev/sdb1 /mnt -o check_int
  49 *
  50 * Example #2, apply integrity checks to all metadata and
  51 * to data extents:
  52 * mount /dev/sdb1 /mnt -o check_int_data
  53 *
  54 * Example #3, apply integrity checks to all metadata and dump
  55 * the tree that the super block references to kernel messages
  56 * each time after a super block was written:
  57 * mount /dev/sdb1 /mnt -o check_int,check_int_print_mask=263
  58 *
  59 * If the integrity check tool is included and activated in
  60 * the mount options, plenty of kernel memory is used, and
  61 * plenty of additional CPU cycles are spent. Enabling this
  62 * functionality is not intended for normal use. In most
  63 * cases, unless you are a btrfs developer who needs to verify
  64 * the integrity of (super)-block write requests, do not
  65 * enable the config option BTRFS_FS_CHECK_INTEGRITY to
  66 * include and compile the integrity check tool.
  67 *
  68 * Expect millions of lines of information in the kernel log with an
  69 * enabled check_int_print_mask. Therefore set LOG_BUF_SHIFT in the
  70 * kernel config to at least 26 (which is 64MB). Usually the value is
  71 * limited to 21 (which is 2MB) in init/Kconfig. The file needs to be
  72 * changed like this before LOG_BUF_SHIFT can be set to a high value:
  73 * config LOG_BUF_SHIFT
  74 *       int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
  75 *       range 12 30
  76 */
  77
  78#include <linux/sched.h>
  79#include <linux/slab.h>
  80#include <linux/buffer_head.h>
  81#include <linux/mutex.h>
  82#include <linux/genhd.h>
  83#include <linux/blkdev.h>
  84#include <linux/mm.h>
  85#include <linux/string.h>
  86#include <linux/crc32c.h>
  87#include "ctree.h"
  88#include "disk-io.h"
  89#include "transaction.h"
  90#include "extent_io.h"
  91#include "volumes.h"
  92#include "print-tree.h"
  93#include "locking.h"
  94#include "check-integrity.h"
  95#include "rcu-string.h"
  96#include "compression.h"
  97
  98#define BTRFSIC_BLOCK_HASHTABLE_SIZE 0x10000
  99#define BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE 0x10000
 100#define BTRFSIC_DEV2STATE_HASHTABLE_SIZE 0x100
 101#define BTRFSIC_BLOCK_MAGIC_NUMBER 0x14491051
 102#define BTRFSIC_BLOCK_LINK_MAGIC_NUMBER 0x11070807
 103#define BTRFSIC_DEV2STATE_MAGIC_NUMBER 0x20111530
 104#define BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER 20111300
 105#define BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL (200 - 6)	/* in characters,
 106							 * excluding " [...]" */
 107#define BTRFSIC_GENERATION_UNKNOWN ((u64)-1)
 108
 109/*
 110 * The definition of the bitmask fields for the print_mask.
 111 * They are specified with the mount option check_integrity_print_mask.
 112 */
 113#define BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE			0x00000001
 114#define BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION		0x00000002
 115#define BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE			0x00000004
 116#define BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE			0x00000008
 117#define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH			0x00000010
 118#define BTRFSIC_PRINT_MASK_END_IO_BIO_BH			0x00000020
 119#define BTRFSIC_PRINT_MASK_VERBOSE				0x00000040
 120#define BTRFSIC_PRINT_MASK_VERY_VERBOSE				0x00000080
 121#define BTRFSIC_PRINT_MASK_INITIAL_TREE				0x00000100
 122#define BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES			0x00000200
 123#define BTRFSIC_PRINT_MASK_INITIAL_DATABASE			0x00000400
 124#define BTRFSIC_PRINT_MASK_NUM_COPIES				0x00000800
 125#define BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS		0x00001000
 126#define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE		0x00002000
 127
 128struct btrfsic_dev_state;
 129struct btrfsic_state;
 130
 131struct btrfsic_block {
 132	u32 magic_num;		/* only used for debug purposes */
 133	unsigned int is_metadata:1;	/* if it is meta-data, not data-data */
 134	unsigned int is_superblock:1;	/* if it is one of the superblocks */
 135	unsigned int is_iodone:1;	/* if is done by lower subsystem */
 136	unsigned int iodone_w_error:1;	/* error was indicated to endio */
 137	unsigned int never_written:1;	/* block was added because it was
 138					 * referenced, not because it was
 139					 * written */
 140	unsigned int mirror_num;	/* large enough to hold
 141					 * BTRFS_SUPER_MIRROR_MAX */
 142	struct btrfsic_dev_state *dev_state;
 143	u64 dev_bytenr;		/* key, physical byte num on disk */
 144	u64 logical_bytenr;	/* logical byte num on disk */
 145	u64 generation;
 146	struct btrfs_disk_key disk_key;	/* extra info to print in case of
 147					 * issues, will not always be correct */
 148	struct list_head collision_resolving_node;	/* list node */
 149	struct list_head all_blocks_node;	/* list node */
 150
 151	/* the following two lists contain block_link items */
 152	struct list_head ref_to_list;	/* list */
 153	struct list_head ref_from_list;	/* list */
 154	struct btrfsic_block *next_in_same_bio;
 155	void *orig_bio_bh_private;
 156	union {
 157		bio_end_io_t *bio;
 158		bh_end_io_t *bh;
 159	} orig_bio_bh_end_io;
 160	int submit_bio_bh_rw;
 161	u64 flush_gen; /* only valid if !never_written */
 162};
 163
 164/*
 165 * Elements of this type are allocated dynamically and required because
 166 * each block object can refer to and can be ref from multiple blocks.
 167 * The key to lookup them in the hashtable is the dev_bytenr of
 168 * the block ref to plus the one from the block referred from.
 169 * The fact that they are searchable via a hashtable and that a
 170 * ref_cnt is maintained is not required for the btrfs integrity
 171 * check algorithm itself, it is only used to make the output more
 172 * beautiful in case that an error is detected (an error is defined
 173 * as a write operation to a block while that block is still referenced).
 174 */
 175struct btrfsic_block_link {
 176	u32 magic_num;		/* only used for debug purposes */
 177	u32 ref_cnt;
 178	struct list_head node_ref_to;	/* list node */
 179	struct list_head node_ref_from;	/* list node */
 180	struct list_head collision_resolving_node;	/* list node */
 181	struct btrfsic_block *block_ref_to;
 182	struct btrfsic_block *block_ref_from;
 183	u64 parent_generation;
 184};
 185
 186struct btrfsic_dev_state {
 187	u32 magic_num;		/* only used for debug purposes */
 188	struct block_device *bdev;
 189	struct btrfsic_state *state;
 190	struct list_head collision_resolving_node;	/* list node */
 191	struct btrfsic_block dummy_block_for_bio_bh_flush;
 192	u64 last_flush_gen;
 193	char name[BDEVNAME_SIZE];
 194};
 195
 196struct btrfsic_block_hashtable {
 197	struct list_head table[BTRFSIC_BLOCK_HASHTABLE_SIZE];
 198};
 199
 200struct btrfsic_block_link_hashtable {
 201	struct list_head table[BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE];
 202};
 203
 204struct btrfsic_dev_state_hashtable {
 205	struct list_head table[BTRFSIC_DEV2STATE_HASHTABLE_SIZE];
 206};
 207
 208struct btrfsic_block_data_ctx {
 209	u64 start;		/* virtual bytenr */
 210	u64 dev_bytenr;		/* physical bytenr on device */
 211	u32 len;
 212	struct btrfsic_dev_state *dev;
 213	char **datav;
 214	struct page **pagev;
 215	void *mem_to_free;
 216};
 217
 218/* This structure is used to implement recursion without occupying
 219 * any stack space, refer to btrfsic_process_metablock() */
 220struct btrfsic_stack_frame {
 221	u32 magic;
 222	u32 nr;
 223	int error;
 224	int i;
 225	int limit_nesting;
 226	int num_copies;
 227	int mirror_num;
 228	struct btrfsic_block *block;
 229	struct btrfsic_block_data_ctx *block_ctx;
 230	struct btrfsic_block *next_block;
 231	struct btrfsic_block_data_ctx next_block_ctx;
 232	struct btrfs_header *hdr;
 233	struct btrfsic_stack_frame *prev;
 234};
 235
 236/* Some state per mounted filesystem */
 237struct btrfsic_state {
 238	u32 print_mask;
 239	int include_extent_data;
 240	int csum_size;
 241	struct list_head all_blocks_list;
 242	struct btrfsic_block_hashtable block_hashtable;
 243	struct btrfsic_block_link_hashtable block_link_hashtable;
 244	struct btrfs_fs_info *fs_info;
 245	u64 max_superblock_generation;
 246	struct btrfsic_block *latest_superblock;
 247	u32 metablock_size;
 248	u32 datablock_size;
 249};
 250
 251static void btrfsic_block_init(struct btrfsic_block *b);
 252static struct btrfsic_block *btrfsic_block_alloc(void);
 253static void btrfsic_block_free(struct btrfsic_block *b);
 254static void btrfsic_block_link_init(struct btrfsic_block_link *n);
 255static struct btrfsic_block_link *btrfsic_block_link_alloc(void);
 256static void btrfsic_block_link_free(struct btrfsic_block_link *n);
 257static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds);
 258static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void);
 259static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds);
 260static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h);
 261static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
 262					struct btrfsic_block_hashtable *h);
 263static void btrfsic_block_hashtable_remove(struct btrfsic_block *b);
 264static struct btrfsic_block *btrfsic_block_hashtable_lookup(
 265		struct block_device *bdev,
 266		u64 dev_bytenr,
 267		struct btrfsic_block_hashtable *h);
 268static void btrfsic_block_link_hashtable_init(
 269		struct btrfsic_block_link_hashtable *h);
 270static void btrfsic_block_link_hashtable_add(
 271		struct btrfsic_block_link *l,
 272		struct btrfsic_block_link_hashtable *h);
 273static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l);
 274static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
 275		struct block_device *bdev_ref_to,
 276		u64 dev_bytenr_ref_to,
 277		struct block_device *bdev_ref_from,
 278		u64 dev_bytenr_ref_from,
 279		struct btrfsic_block_link_hashtable *h);
 280static void btrfsic_dev_state_hashtable_init(
 281		struct btrfsic_dev_state_hashtable *h);
 282static void btrfsic_dev_state_hashtable_add(
 283		struct btrfsic_dev_state *ds,
 284		struct btrfsic_dev_state_hashtable *h);
 285static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds);
 286static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(dev_t dev,
 287		struct btrfsic_dev_state_hashtable *h);
 288static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void);
 289static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf);
 290static int btrfsic_process_superblock(struct btrfsic_state *state,
 291				      struct btrfs_fs_devices *fs_devices);
 292static int btrfsic_process_metablock(struct btrfsic_state *state,
 293				     struct btrfsic_block *block,
 294				     struct btrfsic_block_data_ctx *block_ctx,
 295				     int limit_nesting, int force_iodone_flag);
 296static void btrfsic_read_from_block_data(
 297	struct btrfsic_block_data_ctx *block_ctx,
 298	void *dst, u32 offset, size_t len);
 299static int btrfsic_create_link_to_next_block(
 300		struct btrfsic_state *state,
 301		struct btrfsic_block *block,
 302		struct btrfsic_block_data_ctx
 303		*block_ctx, u64 next_bytenr,
 304		int limit_nesting,
 305		struct btrfsic_block_data_ctx *next_block_ctx,
 306		struct btrfsic_block **next_blockp,
 307		int force_iodone_flag,
 308		int *num_copiesp, int *mirror_nump,
 309		struct btrfs_disk_key *disk_key,
 310		u64 parent_generation);
 311static int btrfsic_handle_extent_data(struct btrfsic_state *state,
 312				      struct btrfsic_block *block,
 313				      struct btrfsic_block_data_ctx *block_ctx,
 314				      u32 item_offset, int force_iodone_flag);
 315static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
 316			     struct btrfsic_block_data_ctx *block_ctx_out,
 317			     int mirror_num);
 318static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx);
 319static int btrfsic_read_block(struct btrfsic_state *state,
 320			      struct btrfsic_block_data_ctx *block_ctx);
 321static void btrfsic_dump_database(struct btrfsic_state *state);
 322static int btrfsic_test_for_metadata(struct btrfsic_state *state,
 323				     char **datav, unsigned int num_pages);
 324static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
 325					  u64 dev_bytenr, char **mapped_datav,
 326					  unsigned int num_pages,
 327					  struct bio *bio, int *bio_is_patched,
 328					  struct buffer_head *bh,
 329					  int submit_bio_bh_rw);
 330static int btrfsic_process_written_superblock(
 331		struct btrfsic_state *state,
 332		struct btrfsic_block *const block,
 333		struct btrfs_super_block *const super_hdr);
 334static void btrfsic_bio_end_io(struct bio *bp);
 335static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate);
 336static int btrfsic_is_block_ref_by_superblock(const struct btrfsic_state *state,
 337					      const struct btrfsic_block *block,
 338					      int recursion_level);
 339static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
 340					struct btrfsic_block *const block,
 341					int recursion_level);
 342static void btrfsic_print_add_link(const struct btrfsic_state *state,
 343				   const struct btrfsic_block_link *l);
 344static void btrfsic_print_rem_link(const struct btrfsic_state *state,
 345				   const struct btrfsic_block_link *l);
 346static char btrfsic_get_block_type(const struct btrfsic_state *state,
 347				   const struct btrfsic_block *block);
 348static void btrfsic_dump_tree(const struct btrfsic_state *state);
 349static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
 350				  const struct btrfsic_block *block,
 351				  int indent_level);
 352static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
 353		struct btrfsic_state *state,
 354		struct btrfsic_block_data_ctx *next_block_ctx,
 355		struct btrfsic_block *next_block,
 356		struct btrfsic_block *from_block,
 357		u64 parent_generation);
 358static struct btrfsic_block *btrfsic_block_lookup_or_add(
 359		struct btrfsic_state *state,
 360		struct btrfsic_block_data_ctx *block_ctx,
 361		const char *additional_string,
 362		int is_metadata,
 363		int is_iodone,
 364		int never_written,
 365		int mirror_num,
 366		int *was_created);
 367static int btrfsic_process_superblock_dev_mirror(
 368		struct btrfsic_state *state,
 369		struct btrfsic_dev_state *dev_state,
 370		struct btrfs_device *device,
 371		int superblock_mirror_num,
 372		struct btrfsic_dev_state **selected_dev_state,
 373		struct btrfs_super_block *selected_super);
 374static struct btrfsic_dev_state *btrfsic_dev_state_lookup(dev_t dev);
 375static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
 376					   u64 bytenr,
 377					   struct btrfsic_dev_state *dev_state,
 378					   u64 dev_bytenr);
 379
 380static struct mutex btrfsic_mutex;
 381static int btrfsic_is_initialized;
 382static struct btrfsic_dev_state_hashtable btrfsic_dev_state_hashtable;
 383
 384
 385static void btrfsic_block_init(struct btrfsic_block *b)
 386{
 387	b->magic_num = BTRFSIC_BLOCK_MAGIC_NUMBER;
 388	b->dev_state = NULL;
 389	b->dev_bytenr = 0;
 390	b->logical_bytenr = 0;
 391	b->generation = BTRFSIC_GENERATION_UNKNOWN;
 392	b->disk_key.objectid = 0;
 393	b->disk_key.type = 0;
 394	b->disk_key.offset = 0;
 395	b->is_metadata = 0;
 396	b->is_superblock = 0;
 397	b->is_iodone = 0;
 398	b->iodone_w_error = 0;
 399	b->never_written = 0;
 400	b->mirror_num = 0;
 401	b->next_in_same_bio = NULL;
 402	b->orig_bio_bh_private = NULL;
 403	b->orig_bio_bh_end_io.bio = NULL;
 404	INIT_LIST_HEAD(&b->collision_resolving_node);
 405	INIT_LIST_HEAD(&b->all_blocks_node);
 406	INIT_LIST_HEAD(&b->ref_to_list);
 407	INIT_LIST_HEAD(&b->ref_from_list);
 408	b->submit_bio_bh_rw = 0;
 409	b->flush_gen = 0;
 410}
 411
 412static struct btrfsic_block *btrfsic_block_alloc(void)
 413{
 414	struct btrfsic_block *b;
 415
 416	b = kzalloc(sizeof(*b), GFP_NOFS);
 417	if (NULL != b)
 418		btrfsic_block_init(b);
 419
 420	return b;
 421}
 422
 423static void btrfsic_block_free(struct btrfsic_block *b)
 424{
 425	BUG_ON(!(NULL == b || BTRFSIC_BLOCK_MAGIC_NUMBER == b->magic_num));
 426	kfree(b);
 427}
 428
 429static void btrfsic_block_link_init(struct btrfsic_block_link *l)
 430{
 431	l->magic_num = BTRFSIC_BLOCK_LINK_MAGIC_NUMBER;
 432	l->ref_cnt = 1;
 433	INIT_LIST_HEAD(&l->node_ref_to);
 434	INIT_LIST_HEAD(&l->node_ref_from);
 435	INIT_LIST_HEAD(&l->collision_resolving_node);
 436	l->block_ref_to = NULL;
 437	l->block_ref_from = NULL;
 438}
 439
 440static struct btrfsic_block_link *btrfsic_block_link_alloc(void)
 441{
 442	struct btrfsic_block_link *l;
 443
 444	l = kzalloc(sizeof(*l), GFP_NOFS);
 445	if (NULL != l)
 446		btrfsic_block_link_init(l);
 447
 448	return l;
 449}
 450
 451static void btrfsic_block_link_free(struct btrfsic_block_link *l)
 452{
 453	BUG_ON(!(NULL == l || BTRFSIC_BLOCK_LINK_MAGIC_NUMBER == l->magic_num));
 454	kfree(l);
 455}
 456
 457static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds)
 458{
 459	ds->magic_num = BTRFSIC_DEV2STATE_MAGIC_NUMBER;
 460	ds->bdev = NULL;
 461	ds->state = NULL;
 462	ds->name[0] = '\0';
 463	INIT_LIST_HEAD(&ds->collision_resolving_node);
 464	ds->last_flush_gen = 0;
 465	btrfsic_block_init(&ds->dummy_block_for_bio_bh_flush);
 466	ds->dummy_block_for_bio_bh_flush.is_iodone = 1;
 467	ds->dummy_block_for_bio_bh_flush.dev_state = ds;
 468}
 469
 470static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void)
 471{
 472	struct btrfsic_dev_state *ds;
 473
 474	ds = kzalloc(sizeof(*ds), GFP_NOFS);
 475	if (NULL != ds)
 476		btrfsic_dev_state_init(ds);
 477
 478	return ds;
 479}
 480
 481static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds)
 482{
 483	BUG_ON(!(NULL == ds ||
 484		 BTRFSIC_DEV2STATE_MAGIC_NUMBER == ds->magic_num));
 485	kfree(ds);
 486}
 487
 488static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h)
 489{
 490	int i;
 491
 492	for (i = 0; i < BTRFSIC_BLOCK_HASHTABLE_SIZE; i++)
 493		INIT_LIST_HEAD(h->table + i);
 494}
 495
 496static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
 497					struct btrfsic_block_hashtable *h)
 498{
 499	const unsigned int hashval =
 500	    (((unsigned int)(b->dev_bytenr >> 16)) ^
 501	     ((unsigned int)((uintptr_t)b->dev_state->bdev))) &
 502	     (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
 503
 504	list_add(&b->collision_resolving_node, h->table + hashval);
 505}
 506
 507static void btrfsic_block_hashtable_remove(struct btrfsic_block *b)
 508{
 509	list_del(&b->collision_resolving_node);
 510}
 511
 512static struct btrfsic_block *btrfsic_block_hashtable_lookup(
 513		struct block_device *bdev,
 514		u64 dev_bytenr,
 515		struct btrfsic_block_hashtable *h)
 516{
 517	const unsigned int hashval =
 518	    (((unsigned int)(dev_bytenr >> 16)) ^
 519	     ((unsigned int)((uintptr_t)bdev))) &
 520	     (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
 521	struct btrfsic_block *b;
 522
 523	list_for_each_entry(b, h->table + hashval, collision_resolving_node) {
 524		if (b->dev_state->bdev == bdev && b->dev_bytenr == dev_bytenr)
 525			return b;
 526	}
 527
 528	return NULL;
 529}
 530
 531static void btrfsic_block_link_hashtable_init(
 532		struct btrfsic_block_link_hashtable *h)
 533{
 534	int i;
 535
 536	for (i = 0; i < BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE; i++)
 537		INIT_LIST_HEAD(h->table + i);
 538}
 539
 540static void btrfsic_block_link_hashtable_add(
 541		struct btrfsic_block_link *l,
 542		struct btrfsic_block_link_hashtable *h)
 543{
 544	const unsigned int hashval =
 545	    (((unsigned int)(l->block_ref_to->dev_bytenr >> 16)) ^
 546	     ((unsigned int)(l->block_ref_from->dev_bytenr >> 16)) ^
 547	     ((unsigned int)((uintptr_t)l->block_ref_to->dev_state->bdev)) ^
 548	     ((unsigned int)((uintptr_t)l->block_ref_from->dev_state->bdev)))
 549	     & (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
 550
 551	BUG_ON(NULL == l->block_ref_to);
 552	BUG_ON(NULL == l->block_ref_from);
 553	list_add(&l->collision_resolving_node, h->table + hashval);
 554}
 555
 556static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l)
 557{
 558	list_del(&l->collision_resolving_node);
 559}
 560
 561static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
 562		struct block_device *bdev_ref_to,
 563		u64 dev_bytenr_ref_to,
 564		struct block_device *bdev_ref_from,
 565		u64 dev_bytenr_ref_from,
 566		struct btrfsic_block_link_hashtable *h)
 567{
 568	const unsigned int hashval =
 569	    (((unsigned int)(dev_bytenr_ref_to >> 16)) ^
 570	     ((unsigned int)(dev_bytenr_ref_from >> 16)) ^
 571	     ((unsigned int)((uintptr_t)bdev_ref_to)) ^
 572	     ((unsigned int)((uintptr_t)bdev_ref_from))) &
 573	     (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
 574	struct btrfsic_block_link *l;
 575
 576	list_for_each_entry(l, h->table + hashval, collision_resolving_node) {
 577		BUG_ON(NULL == l->block_ref_to);
 578		BUG_ON(NULL == l->block_ref_from);
 579		if (l->block_ref_to->dev_state->bdev == bdev_ref_to &&
 580		    l->block_ref_to->dev_bytenr == dev_bytenr_ref_to &&
 581		    l->block_ref_from->dev_state->bdev == bdev_ref_from &&
 582		    l->block_ref_from->dev_bytenr == dev_bytenr_ref_from)
 583			return l;
 584	}
 585
 586	return NULL;
 587}
 588
 589static void btrfsic_dev_state_hashtable_init(
 590		struct btrfsic_dev_state_hashtable *h)
 591{
 592	int i;
 593
 594	for (i = 0; i < BTRFSIC_DEV2STATE_HASHTABLE_SIZE; i++)
 595		INIT_LIST_HEAD(h->table + i);
 596}
 597
 598static void btrfsic_dev_state_hashtable_add(
 599		struct btrfsic_dev_state *ds,
 600		struct btrfsic_dev_state_hashtable *h)
 601{
 602	const unsigned int hashval =
 603	    (((unsigned int)((uintptr_t)ds->bdev->bd_dev)) &
 604	     (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
 605
 606	list_add(&ds->collision_resolving_node, h->table + hashval);
 607}
 608
 609static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds)
 610{
 611	list_del(&ds->collision_resolving_node);
 612}
 613
 614static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(dev_t dev,
 615		struct btrfsic_dev_state_hashtable *h)
 616{
 617	const unsigned int hashval =
 618		dev & (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1);
 619	struct btrfsic_dev_state *ds;
 620
 621	list_for_each_entry(ds, h->table + hashval, collision_resolving_node) {
 622		if (ds->bdev->bd_dev == dev)
 623			return ds;
 624	}
 625
 626	return NULL;
 627}
 628
 629static int btrfsic_process_superblock(struct btrfsic_state *state,
 630				      struct btrfs_fs_devices *fs_devices)
 631{
 632	struct btrfs_fs_info *fs_info = state->fs_info;
 633	struct btrfs_super_block *selected_super;
 634	struct list_head *dev_head = &fs_devices->devices;
 635	struct btrfs_device *device;
 636	struct btrfsic_dev_state *selected_dev_state = NULL;
 637	int ret = 0;
 638	int pass;
 639
 640	BUG_ON(NULL == state);
 641	selected_super = kzalloc(sizeof(*selected_super), GFP_NOFS);
 642	if (NULL == selected_super) {
 643		pr_info("btrfsic: error, kmalloc failed!\n");
 644		return -ENOMEM;
 645	}
 646
 647	list_for_each_entry(device, dev_head, dev_list) {
 648		int i;
 649		struct btrfsic_dev_state *dev_state;
 650
 651		if (!device->bdev || !device->name)
 652			continue;
 653
 654		dev_state = btrfsic_dev_state_lookup(device->bdev->bd_dev);
 655		BUG_ON(NULL == dev_state);
 656		for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 657			ret = btrfsic_process_superblock_dev_mirror(
 658					state, dev_state, device, i,
 659					&selected_dev_state, selected_super);
 660			if (0 != ret && 0 == i) {
 661				kfree(selected_super);
 662				return ret;
 663			}
 664		}
 665	}
 666
 667	if (NULL == state->latest_superblock) {
 668		pr_info("btrfsic: no superblock found!\n");
 669		kfree(selected_super);
 670		return -1;
 671	}
 672
 673	state->csum_size = btrfs_super_csum_size(selected_super);
 674
 675	for (pass = 0; pass < 3; pass++) {
 676		int num_copies;
 677		int mirror_num;
 678		u64 next_bytenr;
 679
 680		switch (pass) {
 681		case 0:
 682			next_bytenr = btrfs_super_root(selected_super);
 683			if (state->print_mask &
 684			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 685				pr_info("root@%llu\n", next_bytenr);
 686			break;
 687		case 1:
 688			next_bytenr = btrfs_super_chunk_root(selected_super);
 689			if (state->print_mask &
 690			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 691				pr_info("chunk@%llu\n", next_bytenr);
 692			break;
 693		case 2:
 694			next_bytenr = btrfs_super_log_root(selected_super);
 695			if (0 == next_bytenr)
 696				continue;
 697			if (state->print_mask &
 698			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 699				pr_info("log@%llu\n", next_bytenr);
 700			break;
 701		}
 702
 703		num_copies = btrfs_num_copies(fs_info, next_bytenr,
 704					      state->metablock_size);
 705		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 706			pr_info("num_copies(log_bytenr=%llu) = %d\n",
 707			       next_bytenr, num_copies);
 708
 709		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 710			struct btrfsic_block *next_block;
 711			struct btrfsic_block_data_ctx tmp_next_block_ctx;
 712			struct btrfsic_block_link *l;
 713
 714			ret = btrfsic_map_block(state, next_bytenr,
 715						state->metablock_size,
 716						&tmp_next_block_ctx,
 717						mirror_num);
 718			if (ret) {
 719				pr_info("btrfsic: btrfsic_map_block(root @%llu, mirror %d) failed!\n",
 720				       next_bytenr, mirror_num);
 721				kfree(selected_super);
 722				return -1;
 723			}
 724
 725			next_block = btrfsic_block_hashtable_lookup(
 726					tmp_next_block_ctx.dev->bdev,
 727					tmp_next_block_ctx.dev_bytenr,
 728					&state->block_hashtable);
 729			BUG_ON(NULL == next_block);
 730
 731			l = btrfsic_block_link_hashtable_lookup(
 732					tmp_next_block_ctx.dev->bdev,
 733					tmp_next_block_ctx.dev_bytenr,
 734					state->latest_superblock->dev_state->
 735					bdev,
 736					state->latest_superblock->dev_bytenr,
 737					&state->block_link_hashtable);
 738			BUG_ON(NULL == l);
 739
 740			ret = btrfsic_read_block(state, &tmp_next_block_ctx);
 741			if (ret < (int)PAGE_SIZE) {
 742				pr_info("btrfsic: read @logical %llu failed!\n",
 743				       tmp_next_block_ctx.start);
 744				btrfsic_release_block_ctx(&tmp_next_block_ctx);
 745				kfree(selected_super);
 746				return -1;
 747			}
 748
 749			ret = btrfsic_process_metablock(state,
 750							next_block,
 751							&tmp_next_block_ctx,
 752							BTRFS_MAX_LEVEL + 3, 1);
 753			btrfsic_release_block_ctx(&tmp_next_block_ctx);
 754		}
 755	}
 756
 757	kfree(selected_super);
 758	return ret;
 759}
 760
 761static int btrfsic_process_superblock_dev_mirror(
 762		struct btrfsic_state *state,
 763		struct btrfsic_dev_state *dev_state,
 764		struct btrfs_device *device,
 765		int superblock_mirror_num,
 766		struct btrfsic_dev_state **selected_dev_state,
 767		struct btrfs_super_block *selected_super)
 768{
 769	struct btrfs_fs_info *fs_info = state->fs_info;
 770	struct btrfs_super_block *super_tmp;
 771	u64 dev_bytenr;
 772	struct buffer_head *bh;
 773	struct btrfsic_block *superblock_tmp;
 774	int pass;
 775	struct block_device *const superblock_bdev = device->bdev;
 776
 777	/* super block bytenr is always the unmapped device bytenr */
 778	dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
 779	if (dev_bytenr + BTRFS_SUPER_INFO_SIZE > device->commit_total_bytes)
 780		return -1;
 781	bh = __bread(superblock_bdev, dev_bytenr / BTRFS_BDEV_BLOCKSIZE,
 782		     BTRFS_SUPER_INFO_SIZE);
 783	if (NULL == bh)
 784		return -1;
 785	super_tmp = (struct btrfs_super_block *)
 786	    (bh->b_data + (dev_bytenr & (BTRFS_BDEV_BLOCKSIZE - 1)));
 787
 788	if (btrfs_super_bytenr(super_tmp) != dev_bytenr ||
 789	    btrfs_super_magic(super_tmp) != BTRFS_MAGIC ||
 790	    memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE) ||
 791	    btrfs_super_nodesize(super_tmp) != state->metablock_size ||
 792	    btrfs_super_sectorsize(super_tmp) != state->datablock_size) {
 793		brelse(bh);
 794		return 0;
 795	}
 796
 797	superblock_tmp =
 798	    btrfsic_block_hashtable_lookup(superblock_bdev,
 799					   dev_bytenr,
 800					   &state->block_hashtable);
 801	if (NULL == superblock_tmp) {
 802		superblock_tmp = btrfsic_block_alloc();
 803		if (NULL == superblock_tmp) {
 804			pr_info("btrfsic: error, kmalloc failed!\n");
 805			brelse(bh);
 806			return -1;
 807		}
 808		/* for superblock, only the dev_bytenr makes sense */
 809		superblock_tmp->dev_bytenr = dev_bytenr;
 810		superblock_tmp->dev_state = dev_state;
 811		superblock_tmp->logical_bytenr = dev_bytenr;
 812		superblock_tmp->generation = btrfs_super_generation(super_tmp);
 813		superblock_tmp->is_metadata = 1;
 814		superblock_tmp->is_superblock = 1;
 815		superblock_tmp->is_iodone = 1;
 816		superblock_tmp->never_written = 0;
 817		superblock_tmp->mirror_num = 1 + superblock_mirror_num;
 818		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
 819			btrfs_info_in_rcu(fs_info,
 820				"new initial S-block (bdev %p, %s) @%llu (%s/%llu/%d)",
 821				     superblock_bdev,
 822				     rcu_str_deref(device->name), dev_bytenr,
 823				     dev_state->name, dev_bytenr,
 824				     superblock_mirror_num);
 825		list_add(&superblock_tmp->all_blocks_node,
 826			 &state->all_blocks_list);
 827		btrfsic_block_hashtable_add(superblock_tmp,
 828					    &state->block_hashtable);
 829	}
 830
 831	/* select the one with the highest generation field */
 832	if (btrfs_super_generation(super_tmp) >
 833	    state->max_superblock_generation ||
 834	    0 == state->max_superblock_generation) {
 835		memcpy(selected_super, super_tmp, sizeof(*selected_super));
 836		*selected_dev_state = dev_state;
 837		state->max_superblock_generation =
 838		    btrfs_super_generation(super_tmp);
 839		state->latest_superblock = superblock_tmp;
 840	}
 841
 842	for (pass = 0; pass < 3; pass++) {
 843		u64 next_bytenr;
 844		int num_copies;
 845		int mirror_num;
 846		const char *additional_string = NULL;
 847		struct btrfs_disk_key tmp_disk_key;
 848
 849		tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
 850		tmp_disk_key.offset = 0;
 851		switch (pass) {
 852		case 0:
 853			btrfs_set_disk_key_objectid(&tmp_disk_key,
 854						    BTRFS_ROOT_TREE_OBJECTID);
 855			additional_string = "initial root ";
 856			next_bytenr = btrfs_super_root(super_tmp);
 857			break;
 858		case 1:
 859			btrfs_set_disk_key_objectid(&tmp_disk_key,
 860						    BTRFS_CHUNK_TREE_OBJECTID);
 861			additional_string = "initial chunk ";
 862			next_bytenr = btrfs_super_chunk_root(super_tmp);
 863			break;
 864		case 2:
 865			btrfs_set_disk_key_objectid(&tmp_disk_key,
 866						    BTRFS_TREE_LOG_OBJECTID);
 867			additional_string = "initial log ";
 868			next_bytenr = btrfs_super_log_root(super_tmp);
 869			if (0 == next_bytenr)
 870				continue;
 871			break;
 872		}
 873
 874		num_copies = btrfs_num_copies(fs_info, next_bytenr,
 875					      state->metablock_size);
 876		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 877			pr_info("num_copies(log_bytenr=%llu) = %d\n",
 878			       next_bytenr, num_copies);
 879		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 880			struct btrfsic_block *next_block;
 881			struct btrfsic_block_data_ctx tmp_next_block_ctx;
 882			struct btrfsic_block_link *l;
 883
 884			if (btrfsic_map_block(state, next_bytenr,
 885					      state->metablock_size,
 886					      &tmp_next_block_ctx,
 887					      mirror_num)) {
 888				pr_info("btrfsic: btrfsic_map_block(bytenr @%llu, mirror %d) failed!\n",
 889				       next_bytenr, mirror_num);
 890				brelse(bh);
 891				return -1;
 892			}
 893
 894			next_block = btrfsic_block_lookup_or_add(
 895					state, &tmp_next_block_ctx,
 896					additional_string, 1, 1, 0,
 897					mirror_num, NULL);
 898			if (NULL == next_block) {
 899				btrfsic_release_block_ctx(&tmp_next_block_ctx);
 900				brelse(bh);
 901				return -1;
 902			}
 903
 904			next_block->disk_key = tmp_disk_key;
 905			next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
 906			l = btrfsic_block_link_lookup_or_add(
 907					state, &tmp_next_block_ctx,
 908					next_block, superblock_tmp,
 909					BTRFSIC_GENERATION_UNKNOWN);
 910			btrfsic_release_block_ctx(&tmp_next_block_ctx);
 911			if (NULL == l) {
 912				brelse(bh);
 913				return -1;
 914			}
 915		}
 916	}
 917	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES)
 918		btrfsic_dump_tree_sub(state, superblock_tmp, 0);
 919
 920	brelse(bh);
 921	return 0;
 922}
 923
 924static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void)
 925{
 926	struct btrfsic_stack_frame *sf;
 927
 928	sf = kzalloc(sizeof(*sf), GFP_NOFS);
 929	if (NULL == sf)
 930		pr_info("btrfsic: alloc memory failed!\n");
 931	else
 932		sf->magic = BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER;
 933	return sf;
 934}
 935
 936static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf)
 937{
 938	BUG_ON(!(NULL == sf ||
 939		 BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER == sf->magic));
 940	kfree(sf);
 941}
 942
 943static int btrfsic_process_metablock(
 944		struct btrfsic_state *state,
 945		struct btrfsic_block *const first_block,
 946		struct btrfsic_block_data_ctx *const first_block_ctx,
 947		int first_limit_nesting, int force_iodone_flag)
 948{
 949	struct btrfsic_stack_frame initial_stack_frame = { 0 };
 950	struct btrfsic_stack_frame *sf;
 951	struct btrfsic_stack_frame *next_stack;
 952	struct btrfs_header *const first_hdr =
 953		(struct btrfs_header *)first_block_ctx->datav[0];
 954
 955	BUG_ON(!first_hdr);
 956	sf = &initial_stack_frame;
 957	sf->error = 0;
 958	sf->i = -1;
 959	sf->limit_nesting = first_limit_nesting;
 960	sf->block = first_block;
 961	sf->block_ctx = first_block_ctx;
 962	sf->next_block = NULL;
 963	sf->hdr = first_hdr;
 964	sf->prev = NULL;
 965
 966continue_with_new_stack_frame:
 967	sf->block->generation = le64_to_cpu(sf->hdr->generation);
 968	if (0 == sf->hdr->level) {
 969		struct btrfs_leaf *const leafhdr =
 970		    (struct btrfs_leaf *)sf->hdr;
 971
 972		if (-1 == sf->i) {
 973			sf->nr = btrfs_stack_header_nritems(&leafhdr->header);
 974
 975			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
 976				pr_info("leaf %llu items %d generation %llu owner %llu\n",
 977				       sf->block_ctx->start, sf->nr,
 978				       btrfs_stack_header_generation(
 979					       &leafhdr->header),
 980				       btrfs_stack_header_owner(
 981					       &leafhdr->header));
 982		}
 983
 984continue_with_current_leaf_stack_frame:
 985		if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
 986			sf->i++;
 987			sf->num_copies = 0;
 988		}
 989
 990		if (sf->i < sf->nr) {
 991			struct btrfs_item disk_item;
 992			u32 disk_item_offset =
 993				(uintptr_t)(leafhdr->items + sf->i) -
 994				(uintptr_t)leafhdr;
 995			struct btrfs_disk_key *disk_key;
 996			u8 type;
 997			u32 item_offset;
 998			u32 item_size;
 999
1000			if (disk_item_offset + sizeof(struct btrfs_item) >
1001			    sf->block_ctx->len) {
1002leaf_item_out_of_bounce_error:
1003				pr_info("btrfsic: leaf item out of bounce at logical %llu, dev %s\n",
1004				       sf->block_ctx->start,
1005				       sf->block_ctx->dev->name);
1006				goto one_stack_frame_backwards;
1007			}
1008			btrfsic_read_from_block_data(sf->block_ctx,
1009						     &disk_item,
1010						     disk_item_offset,
1011						     sizeof(struct btrfs_item));
1012			item_offset = btrfs_stack_item_offset(&disk_item);
1013			item_size = btrfs_stack_item_size(&disk_item);
1014			disk_key = &disk_item.key;
1015			type = btrfs_disk_key_type(disk_key);
1016
1017			if (BTRFS_ROOT_ITEM_KEY == type) {
1018				struct btrfs_root_item root_item;
1019				u32 root_item_offset;
1020				u64 next_bytenr;
1021
1022				root_item_offset = item_offset +
1023					offsetof(struct btrfs_leaf, items);
1024				if (root_item_offset + item_size >
1025				    sf->block_ctx->len)
1026					goto leaf_item_out_of_bounce_error;
1027				btrfsic_read_from_block_data(
1028					sf->block_ctx, &root_item,
1029					root_item_offset,
1030					item_size);
1031				next_bytenr = btrfs_root_bytenr(&root_item);
1032
1033				sf->error =
1034				    btrfsic_create_link_to_next_block(
1035						state,
1036						sf->block,
1037						sf->block_ctx,
1038						next_bytenr,
1039						sf->limit_nesting,
1040						&sf->next_block_ctx,
1041						&sf->next_block,
1042						force_iodone_flag,
1043						&sf->num_copies,
1044						&sf->mirror_num,
1045						disk_key,
1046						btrfs_root_generation(
1047						&root_item));
1048				if (sf->error)
1049					goto one_stack_frame_backwards;
1050
1051				if (NULL != sf->next_block) {
1052					struct btrfs_header *const next_hdr =
1053					    (struct btrfs_header *)
1054					    sf->next_block_ctx.datav[0];
1055
1056					next_stack =
1057					    btrfsic_stack_frame_alloc();
1058					if (NULL == next_stack) {
1059						sf->error = -1;
1060						btrfsic_release_block_ctx(
1061								&sf->
1062								next_block_ctx);
1063						goto one_stack_frame_backwards;
1064					}
1065
1066					next_stack->i = -1;
1067					next_stack->block = sf->next_block;
1068					next_stack->block_ctx =
1069					    &sf->next_block_ctx;
1070					next_stack->next_block = NULL;
1071					next_stack->hdr = next_hdr;
1072					next_stack->limit_nesting =
1073					    sf->limit_nesting - 1;
1074					next_stack->prev = sf;
1075					sf = next_stack;
1076					goto continue_with_new_stack_frame;
1077				}
1078			} else if (BTRFS_EXTENT_DATA_KEY == type &&
1079				   state->include_extent_data) {
1080				sf->error = btrfsic_handle_extent_data(
1081						state,
1082						sf->block,
1083						sf->block_ctx,
1084						item_offset,
1085						force_iodone_flag);
1086				if (sf->error)
1087					goto one_stack_frame_backwards;
1088			}
1089
1090			goto continue_with_current_leaf_stack_frame;
1091		}
1092	} else {
1093		struct btrfs_node *const nodehdr = (struct btrfs_node *)sf->hdr;
1094
1095		if (-1 == sf->i) {
1096			sf->nr = btrfs_stack_header_nritems(&nodehdr->header);
1097
1098			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1099				pr_info("node %llu level %d items %d generation %llu owner %llu\n",
1100				       sf->block_ctx->start,
1101				       nodehdr->header.level, sf->nr,
1102				       btrfs_stack_header_generation(
1103				       &nodehdr->header),
1104				       btrfs_stack_header_owner(
1105				       &nodehdr->header));
1106		}
1107
1108continue_with_current_node_stack_frame:
1109		if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1110			sf->i++;
1111			sf->num_copies = 0;
1112		}
1113
1114		if (sf->i < sf->nr) {
1115			struct btrfs_key_ptr key_ptr;
1116			u32 key_ptr_offset;
1117			u64 next_bytenr;
1118
1119			key_ptr_offset = (uintptr_t)(nodehdr->ptrs + sf->i) -
1120					  (uintptr_t)nodehdr;
1121			if (key_ptr_offset + sizeof(struct btrfs_key_ptr) >
1122			    sf->block_ctx->len) {
1123				pr_info("btrfsic: node item out of bounce at logical %llu, dev %s\n",
1124				       sf->block_ctx->start,
1125				       sf->block_ctx->dev->name);
1126				goto one_stack_frame_backwards;
1127			}
1128			btrfsic_read_from_block_data(
1129				sf->block_ctx, &key_ptr, key_ptr_offset,
1130				sizeof(struct btrfs_key_ptr));
1131			next_bytenr = btrfs_stack_key_blockptr(&key_ptr);
1132
1133			sf->error = btrfsic_create_link_to_next_block(
1134					state,
1135					sf->block,
1136					sf->block_ctx,
1137					next_bytenr,
1138					sf->limit_nesting,
1139					&sf->next_block_ctx,
1140					&sf->next_block,
1141					force_iodone_flag,
1142					&sf->num_copies,
1143					&sf->mirror_num,
1144					&key_ptr.key,
1145					btrfs_stack_key_generation(&key_ptr));
1146			if (sf->error)
1147				goto one_stack_frame_backwards;
1148
1149			if (NULL != sf->next_block) {
1150				struct btrfs_header *const next_hdr =
1151				    (struct btrfs_header *)
1152				    sf->next_block_ctx.datav[0];
1153
1154				next_stack = btrfsic_stack_frame_alloc();
1155				if (NULL == next_stack) {
1156					sf->error = -1;
1157					goto one_stack_frame_backwards;
1158				}
1159
1160				next_stack->i = -1;
1161				next_stack->block = sf->next_block;
1162				next_stack->block_ctx = &sf->next_block_ctx;
1163				next_stack->next_block = NULL;
1164				next_stack->hdr = next_hdr;
1165				next_stack->limit_nesting =
1166				    sf->limit_nesting - 1;
1167				next_stack->prev = sf;
1168				sf = next_stack;
1169				goto continue_with_new_stack_frame;
1170			}
1171
1172			goto continue_with_current_node_stack_frame;
1173		}
1174	}
1175
1176one_stack_frame_backwards:
1177	if (NULL != sf->prev) {
1178		struct btrfsic_stack_frame *const prev = sf->prev;
1179
1180		/* the one for the initial block is freed in the caller */
1181		btrfsic_release_block_ctx(sf->block_ctx);
1182
1183		if (sf->error) {
1184			prev->error = sf->error;
1185			btrfsic_stack_frame_free(sf);
1186			sf = prev;
1187			goto one_stack_frame_backwards;
1188		}
1189
1190		btrfsic_stack_frame_free(sf);
1191		sf = prev;
1192		goto continue_with_new_stack_frame;
1193	} else {
1194		BUG_ON(&initial_stack_frame != sf);
1195	}
1196
1197	return sf->error;
1198}
1199
1200static void btrfsic_read_from_block_data(
1201	struct btrfsic_block_data_ctx *block_ctx,
1202	void *dstv, u32 offset, size_t len)
1203{
1204	size_t cur;
1205	size_t offset_in_page;
1206	char *kaddr;
1207	char *dst = (char *)dstv;
1208	size_t start_offset = block_ctx->start & ((u64)PAGE_SIZE - 1);
1209	unsigned long i = (start_offset + offset) >> PAGE_SHIFT;
1210
1211	WARN_ON(offset + len > block_ctx->len);
1212	offset_in_page = (start_offset + offset) & (PAGE_SIZE - 1);
1213
1214	while (len > 0) {
1215		cur = min(len, ((size_t)PAGE_SIZE - offset_in_page));
1216		BUG_ON(i >= DIV_ROUND_UP(block_ctx->len, PAGE_SIZE));
1217		kaddr = block_ctx->datav[i];
1218		memcpy(dst, kaddr + offset_in_page, cur);
1219
1220		dst += cur;
1221		len -= cur;
1222		offset_in_page = 0;
1223		i++;
1224	}
1225}
1226
1227static int btrfsic_create_link_to_next_block(
1228		struct btrfsic_state *state,
1229		struct btrfsic_block *block,
1230		struct btrfsic_block_data_ctx *block_ctx,
1231		u64 next_bytenr,
1232		int limit_nesting,
1233		struct btrfsic_block_data_ctx *next_block_ctx,
1234		struct btrfsic_block **next_blockp,
1235		int force_iodone_flag,
1236		int *num_copiesp, int *mirror_nump,
1237		struct btrfs_disk_key *disk_key,
1238		u64 parent_generation)
1239{
1240	struct btrfs_fs_info *fs_info = state->fs_info;
1241	struct btrfsic_block *next_block = NULL;
1242	int ret;
1243	struct btrfsic_block_link *l;
1244	int did_alloc_block_link;
1245	int block_was_created;
1246
1247	*next_blockp = NULL;
1248	if (0 == *num_copiesp) {
1249		*num_copiesp = btrfs_num_copies(fs_info, next_bytenr,
1250						state->metablock_size);
1251		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1252			pr_info("num_copies(log_bytenr=%llu) = %d\n",
1253			       next_bytenr, *num_copiesp);
1254		*mirror_nump = 1;
1255	}
1256
1257	if (*mirror_nump > *num_copiesp)
1258		return 0;
1259
1260	if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1261		pr_info("btrfsic_create_link_to_next_block(mirror_num=%d)\n",
1262		       *mirror_nump);
1263	ret = btrfsic_map_block(state, next_bytenr,
1264				state->metablock_size,
1265				next_block_ctx, *mirror_nump);
1266	if (ret) {
1267		pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1268		       next_bytenr, *mirror_nump);
1269		btrfsic_release_block_ctx(next_block_ctx);
1270		*next_blockp = NULL;
1271		return -1;
1272	}
1273
1274	next_block = btrfsic_block_lookup_or_add(state,
1275						 next_block_ctx, "referenced ",
1276						 1, force_iodone_flag,
1277						 !force_iodone_flag,
1278						 *mirror_nump,
1279						 &block_was_created);
1280	if (NULL == next_block) {
1281		btrfsic_release_block_ctx(next_block_ctx);
1282		*next_blockp = NULL;
1283		return -1;
1284	}
1285	if (block_was_created) {
1286		l = NULL;
1287		next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
1288	} else {
1289		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE) {
1290			if (next_block->logical_bytenr != next_bytenr &&
1291			    !(!next_block->is_metadata &&
1292			      0 == next_block->logical_bytenr))
1293				pr_info("Referenced block @%llu (%s/%llu/%d) found in hash table, %c, bytenr mismatch (!= stored %llu).\n",
1294				       next_bytenr, next_block_ctx->dev->name,
1295				       next_block_ctx->dev_bytenr, *mirror_nump,
1296				       btrfsic_get_block_type(state,
1297							      next_block),
1298				       next_block->logical_bytenr);
1299			else
1300				pr_info("Referenced block @%llu (%s/%llu/%d) found in hash table, %c.\n",
1301				       next_bytenr, next_block_ctx->dev->name,
1302				       next_block_ctx->dev_bytenr, *mirror_nump,
1303				       btrfsic_get_block_type(state,
1304							      next_block));
1305		}
1306		next_block->logical_bytenr = next_bytenr;
1307
1308		next_block->mirror_num = *mirror_nump;
1309		l = btrfsic_block_link_hashtable_lookup(
1310				next_block_ctx->dev->bdev,
1311				next_block_ctx->dev_bytenr,
1312				block_ctx->dev->bdev,
1313				block_ctx->dev_bytenr,
1314				&state->block_link_hashtable);
1315	}
1316
1317	next_block->disk_key = *disk_key;
1318	if (NULL == l) {
1319		l = btrfsic_block_link_alloc();
1320		if (NULL == l) {
1321			pr_info("btrfsic: error, kmalloc failed!\n");
1322			btrfsic_release_block_ctx(next_block_ctx);
1323			*next_blockp = NULL;
1324			return -1;
1325		}
1326
1327		did_alloc_block_link = 1;
1328		l->block_ref_to = next_block;
1329		l->block_ref_from = block;
1330		l->ref_cnt = 1;
1331		l->parent_generation = parent_generation;
1332
1333		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1334			btrfsic_print_add_link(state, l);
1335
1336		list_add(&l->node_ref_to, &block->ref_to_list);
1337		list_add(&l->node_ref_from, &next_block->ref_from_list);
1338
1339		btrfsic_block_link_hashtable_add(l,
1340						 &state->block_link_hashtable);
1341	} else {
1342		did_alloc_block_link = 0;
1343		if (0 == limit_nesting) {
1344			l->ref_cnt++;
1345			l->parent_generation = parent_generation;
1346			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1347				btrfsic_print_add_link(state, l);
1348		}
1349	}
1350
1351	if (limit_nesting > 0 && did_alloc_block_link) {
1352		ret = btrfsic_read_block(state, next_block_ctx);
1353		if (ret < (int)next_block_ctx->len) {
1354			pr_info("btrfsic: read block @logical %llu failed!\n",
1355			       next_bytenr);
1356			btrfsic_release_block_ctx(next_block_ctx);
1357			*next_blockp = NULL;
1358			return -1;
1359		}
1360
1361		*next_blockp = next_block;
1362	} else {
1363		*next_blockp = NULL;
1364	}
1365	(*mirror_nump)++;
1366
1367	return 0;
1368}
1369
1370static int btrfsic_handle_extent_data(
1371		struct btrfsic_state *state,
1372		struct btrfsic_block *block,
1373		struct btrfsic_block_data_ctx *block_ctx,
1374		u32 item_offset, int force_iodone_flag)
1375{
1376	struct btrfs_fs_info *fs_info = state->fs_info;
1377	struct btrfs_file_extent_item file_extent_item;
1378	u64 file_extent_item_offset;
1379	u64 next_bytenr;
1380	u64 num_bytes;
1381	u64 generation;
1382	struct btrfsic_block_link *l;
1383	int ret;
1384
1385	file_extent_item_offset = offsetof(struct btrfs_leaf, items) +
1386				  item_offset;
1387	if (file_extent_item_offset +
1388	    offsetof(struct btrfs_file_extent_item, disk_num_bytes) >
1389	    block_ctx->len) {
1390		pr_info("btrfsic: file item out of bounce at logical %llu, dev %s\n",
1391		       block_ctx->start, block_ctx->dev->name);
1392		return -1;
1393	}
1394
1395	btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1396		file_extent_item_offset,
1397		offsetof(struct btrfs_file_extent_item, disk_num_bytes));
1398	if (BTRFS_FILE_EXTENT_REG != file_extent_item.type ||
1399	    btrfs_stack_file_extent_disk_bytenr(&file_extent_item) == 0) {
1400		if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1401			pr_info("extent_data: type %u, disk_bytenr = %llu\n",
1402			       file_extent_item.type,
1403			       btrfs_stack_file_extent_disk_bytenr(
1404			       &file_extent_item));
1405		return 0;
1406	}
1407
1408	if (file_extent_item_offset + sizeof(struct btrfs_file_extent_item) >
1409	    block_ctx->len) {
1410		pr_info("btrfsic: file item out of bounce at logical %llu, dev %s\n",
1411		       block_ctx->start, block_ctx->dev->name);
1412		return -1;
1413	}
1414	btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1415				     file_extent_item_offset,
1416				     sizeof(struct btrfs_file_extent_item));
1417	next_bytenr = btrfs_stack_file_extent_disk_bytenr(&file_extent_item);
1418	if (btrfs_stack_file_extent_compression(&file_extent_item) ==
1419	    BTRFS_COMPRESS_NONE) {
1420		next_bytenr += btrfs_stack_file_extent_offset(&file_extent_item);
1421		num_bytes = btrfs_stack_file_extent_num_bytes(&file_extent_item);
1422	} else {
1423		num_bytes = btrfs_stack_file_extent_disk_num_bytes(&file_extent_item);
1424	}
1425	generation = btrfs_stack_file_extent_generation(&file_extent_item);
1426
1427	if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1428		pr_info("extent_data: type %u, disk_bytenr = %llu, offset = %llu, num_bytes = %llu\n",
1429		       file_extent_item.type,
1430		       btrfs_stack_file_extent_disk_bytenr(&file_extent_item),
1431		       btrfs_stack_file_extent_offset(&file_extent_item),
1432		       num_bytes);
1433	while (num_bytes > 0) {
1434		u32 chunk_len;
1435		int num_copies;
1436		int mirror_num;
1437
1438		if (num_bytes > state->datablock_size)
1439			chunk_len = state->datablock_size;
1440		else
1441			chunk_len = num_bytes;
1442
1443		num_copies = btrfs_num_copies(fs_info, next_bytenr,
1444					      state->datablock_size);
1445		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1446			pr_info("num_copies(log_bytenr=%llu) = %d\n",
1447			       next_bytenr, num_copies);
1448		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
1449			struct btrfsic_block_data_ctx next_block_ctx;
1450			struct btrfsic_block *next_block;
1451			int block_was_created;
1452
1453			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1454				pr_info("btrfsic_handle_extent_data(mirror_num=%d)\n",
1455					mirror_num);
1456			if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1457				pr_info("\tdisk_bytenr = %llu, num_bytes %u\n",
1458				       next_bytenr, chunk_len);
1459			ret = btrfsic_map_block(state, next_bytenr,
1460						chunk_len, &next_block_ctx,
1461						mirror_num);
1462			if (ret) {
1463				pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1464				       next_bytenr, mirror_num);
1465				return -1;
1466			}
1467
1468			next_block = btrfsic_block_lookup_or_add(
1469					state,
1470					&next_block_ctx,
1471					"referenced ",
1472					0,
1473					force_iodone_flag,
1474					!force_iodone_flag,
1475					mirror_num,
1476					&block_was_created);
1477			if (NULL == next_block) {
1478				pr_info("btrfsic: error, kmalloc failed!\n");
1479				btrfsic_release_block_ctx(&next_block_ctx);
1480				return -1;
1481			}
1482			if (!block_was_created) {
1483				if ((state->print_mask &
1484				     BTRFSIC_PRINT_MASK_VERBOSE) &&
1485				    next_block->logical_bytenr != next_bytenr &&
1486				    !(!next_block->is_metadata &&
1487				      0 == next_block->logical_bytenr)) {
1488					pr_info("Referenced block @%llu (%s/%llu/%d) found in hash table, D, bytenr mismatch (!= stored %llu).\n",
1489					       next_bytenr,
1490					       next_block_ctx.dev->name,
1491					       next_block_ctx.dev_bytenr,
1492					       mirror_num,
1493					       next_block->logical_bytenr);
1494				}
1495				next_block->logical_bytenr = next_bytenr;
1496				next_block->mirror_num = mirror_num;
1497			}
1498
1499			l = btrfsic_block_link_lookup_or_add(state,
1500							     &next_block_ctx,
1501							     next_block, block,
1502							     generation);
1503			btrfsic_release_block_ctx(&next_block_ctx);
1504			if (NULL == l)
1505				return -1;
1506		}
1507
1508		next_bytenr += chunk_len;
1509		num_bytes -= chunk_len;
1510	}
1511
1512	return 0;
1513}
1514
1515static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
1516			     struct btrfsic_block_data_ctx *block_ctx_out,
1517			     int mirror_num)
1518{
1519	struct btrfs_fs_info *fs_info = state->fs_info;
1520	int ret;
1521	u64 length;
1522	struct btrfs_bio *multi = NULL;
1523	struct btrfs_device *device;
1524
1525	length = len;
1526	ret = btrfs_map_block(fs_info, BTRFS_MAP_READ,
1527			      bytenr, &length, &multi, mirror_num);
1528
1529	if (ret) {
1530		block_ctx_out->start = 0;
1531		block_ctx_out->dev_bytenr = 0;
1532		block_ctx_out->len = 0;
1533		block_ctx_out->dev = NULL;
1534		block_ctx_out->datav = NULL;
1535		block_ctx_out->pagev = NULL;
1536		block_ctx_out->mem_to_free = NULL;
1537
1538		return ret;
1539	}
1540
1541	device = multi->stripes[0].dev;
1542	block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev->bd_dev);
1543	block_ctx_out->dev_bytenr = multi->stripes[0].physical;
1544	block_ctx_out->start = bytenr;
1545	block_ctx_out->len = len;
1546	block_ctx_out->datav = NULL;
1547	block_ctx_out->pagev = NULL;
1548	block_ctx_out->mem_to_free = NULL;
1549
1550	kfree(multi);
1551	if (NULL == block_ctx_out->dev) {
1552		ret = -ENXIO;
1553		pr_info("btrfsic: error, cannot lookup dev (#1)!\n");
1554	}
1555
1556	return ret;
1557}
1558
1559static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
1560{
1561	if (block_ctx->mem_to_free) {
1562		unsigned int num_pages;
1563
1564		BUG_ON(!block_ctx->datav);
1565		BUG_ON(!block_ctx->pagev);
1566		num_pages = (block_ctx->len + (u64)PAGE_SIZE - 1) >>
1567			    PAGE_SHIFT;
1568		while (num_pages > 0) {
1569			num_pages--;
1570			if (block_ctx->datav[num_pages]) {
1571				kunmap(block_ctx->pagev[num_pages]);
1572				block_ctx->datav[num_pages] = NULL;
1573			}
1574			if (block_ctx->pagev[num_pages]) {
1575				__free_page(block_ctx->pagev[num_pages]);
1576				block_ctx->pagev[num_pages] = NULL;
1577			}
1578		}
1579
1580		kfree(block_ctx->mem_to_free);
1581		block_ctx->mem_to_free = NULL;
1582		block_ctx->pagev = NULL;
1583		block_ctx->datav = NULL;
1584	}
1585}
1586
1587static int btrfsic_read_block(struct btrfsic_state *state,
1588			      struct btrfsic_block_data_ctx *block_ctx)
1589{
1590	unsigned int num_pages;
1591	unsigned int i;
1592	u64 dev_bytenr;
1593	int ret;
1594
1595	BUG_ON(block_ctx->datav);
1596	BUG_ON(block_ctx->pagev);
1597	BUG_ON(block_ctx->mem_to_free);
1598	if (block_ctx->dev_bytenr & ((u64)PAGE_SIZE - 1)) {
1599		pr_info("btrfsic: read_block() with unaligned bytenr %llu\n",
1600		       block_ctx->dev_bytenr);
1601		return -1;
1602	}
1603
1604	num_pages = (block_ctx->len + (u64)PAGE_SIZE - 1) >>
1605		    PAGE_SHIFT;
1606	block_ctx->mem_to_free = kzalloc((sizeof(*block_ctx->datav) +
1607					  sizeof(*block_ctx->pagev)) *
1608					 num_pages, GFP_NOFS);
1609	if (!block_ctx->mem_to_free)
1610		return -ENOMEM;
1611	block_ctx->datav = block_ctx->mem_to_free;
1612	block_ctx->pagev = (struct page **)(block_ctx->datav + num_pages);
1613	for (i = 0; i < num_pages; i++) {
1614		block_ctx->pagev[i] = alloc_page(GFP_NOFS);
1615		if (!block_ctx->pagev[i])
1616			return -1;
1617	}
1618
1619	dev_bytenr = block_ctx->dev_bytenr;
1620	for (i = 0; i < num_pages;) {
1621		struct bio *bio;
1622		unsigned int j;
1623
1624		bio = btrfs_io_bio_alloc(num_pages - i);
1625		bio_set_dev(bio, block_ctx->dev->bdev);
1626		bio->bi_iter.bi_sector = dev_bytenr >> 9;
1627		bio_set_op_attrs(bio, REQ_OP_READ, 0);
1628
1629		for (j = i; j < num_pages; j++) {
1630			ret = bio_add_page(bio, block_ctx->pagev[j],
1631					   PAGE_SIZE, 0);
1632			if (PAGE_SIZE != ret)
1633				break;
1634		}
1635		if (j == i) {
1636			pr_info("btrfsic: error, failed to add a single page!\n");
1637			return -1;
1638		}
1639		if (submit_bio_wait(bio)) {
1640			pr_info("btrfsic: read error at logical %llu dev %s!\n",
1641			       block_ctx->start, block_ctx->dev->name);
1642			bio_put(bio);
1643			return -1;
1644		}
1645		bio_put(bio);
1646		dev_bytenr += (j - i) * PAGE_SIZE;
1647		i = j;
1648	}
1649	for (i = 0; i < num_pages; i++)
1650		block_ctx->datav[i] = kmap(block_ctx->pagev[i]);
1651
1652	return block_ctx->len;
1653}
1654
1655static void btrfsic_dump_database(struct btrfsic_state *state)
1656{
1657	const struct btrfsic_block *b_all;
1658
1659	BUG_ON(NULL == state);
1660
1661	pr_info("all_blocks_list:\n");
1662	list_for_each_entry(b_all, &state->all_blocks_list, all_blocks_node) {
1663		const struct btrfsic_block_link *l;
1664
1665		pr_info("%c-block @%llu (%s/%llu/%d)\n",
1666		       btrfsic_get_block_type(state, b_all),
1667		       b_all->logical_bytenr, b_all->dev_state->name,
1668		       b_all->dev_bytenr, b_all->mirror_num);
1669
1670		list_for_each_entry(l, &b_all->ref_to_list, node_ref_to) {
1671			pr_info(" %c @%llu (%s/%llu/%d) refers %u* to %c @%llu (%s/%llu/%d)\n",
1672			       btrfsic_get_block_type(state, b_all),
1673			       b_all->logical_bytenr, b_all->dev_state->name,
1674			       b_all->dev_bytenr, b_all->mirror_num,
1675			       l->ref_cnt,
1676			       btrfsic_get_block_type(state, l->block_ref_to),
1677			       l->block_ref_to->logical_bytenr,
1678			       l->block_ref_to->dev_state->name,
1679			       l->block_ref_to->dev_bytenr,
1680			       l->block_ref_to->mirror_num);
1681		}
1682
1683		list_for_each_entry(l, &b_all->ref_from_list, node_ref_from) {
1684			pr_info(" %c @%llu (%s/%llu/%d) is ref %u* from %c @%llu (%s/%llu/%d)\n",
1685			       btrfsic_get_block_type(state, b_all),
1686			       b_all->logical_bytenr, b_all->dev_state->name,
1687			       b_all->dev_bytenr, b_all->mirror_num,
1688			       l->ref_cnt,
1689			       btrfsic_get_block_type(state, l->block_ref_from),
1690			       l->block_ref_from->logical_bytenr,
1691			       l->block_ref_from->dev_state->name,
1692			       l->block_ref_from->dev_bytenr,
1693			       l->block_ref_from->mirror_num);
1694		}
1695
1696		pr_info("\n");
1697	}
1698}
1699
1700/*
1701 * Test whether the disk block contains a tree block (leaf or node)
1702 * (note that this test fails for the super block)
1703 */
1704static int btrfsic_test_for_metadata(struct btrfsic_state *state,
1705				     char **datav, unsigned int num_pages)
1706{
1707	struct btrfs_fs_info *fs_info = state->fs_info;
1708	struct btrfs_header *h;
1709	u8 csum[BTRFS_CSUM_SIZE];
1710	u32 crc = ~(u32)0;
1711	unsigned int i;
1712
1713	if (num_pages * PAGE_SIZE < state->metablock_size)
1714		return 1; /* not metadata */
1715	num_pages = state->metablock_size >> PAGE_SHIFT;
1716	h = (struct btrfs_header *)datav[0];
1717
1718	if (memcmp(h->fsid, fs_info->fsid, BTRFS_FSID_SIZE))
1719		return 1;
1720
1721	for (i = 0; i < num_pages; i++) {
1722		u8 *data = i ? datav[i] : (datav[i] + BTRFS_CSUM_SIZE);
1723		size_t sublen = i ? PAGE_SIZE :
1724				    (PAGE_SIZE - BTRFS_CSUM_SIZE);
1725
1726		crc = crc32c(crc, data, sublen);
1727	}
1728	btrfs_csum_final(crc, csum);
1729	if (memcmp(csum, h->csum, state->csum_size))
1730		return 1;
1731
1732	return 0; /* is metadata */
1733}
1734
1735static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
1736					  u64 dev_bytenr, char **mapped_datav,
1737					  unsigned int num_pages,
1738					  struct bio *bio, int *bio_is_patched,
1739					  struct buffer_head *bh,
1740					  int submit_bio_bh_rw)
1741{
1742	int is_metadata;
1743	struct btrfsic_block *block;
1744	struct btrfsic_block_data_ctx block_ctx;
1745	int ret;
1746	struct btrfsic_state *state = dev_state->state;
1747	struct block_device *bdev = dev_state->bdev;
1748	unsigned int processed_len;
1749
1750	if (NULL != bio_is_patched)
1751		*bio_is_patched = 0;
1752
1753again:
1754	if (num_pages == 0)
1755		return;
1756
1757	processed_len = 0;
1758	is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_datav,
1759						      num_pages));
1760
1761	block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
1762					       &state->block_hashtable);
1763	if (NULL != block) {
1764		u64 bytenr = 0;
1765		struct btrfsic_block_link *l, *tmp;
1766
1767		if (block->is_superblock) {
1768			bytenr = btrfs_super_bytenr((struct btrfs_super_block *)
1769						    mapped_datav[0]);
1770			if (num_pages * PAGE_SIZE <
1771			    BTRFS_SUPER_INFO_SIZE) {
1772				pr_info("btrfsic: cannot work with too short bios!\n");
1773				return;
1774			}
1775			is_metadata = 1;
1776			BUG_ON(BTRFS_SUPER_INFO_SIZE & (PAGE_SIZE - 1));
1777			processed_len = BTRFS_SUPER_INFO_SIZE;
1778			if (state->print_mask &
1779			    BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
1780				pr_info("[before new superblock is written]:\n");
1781				btrfsic_dump_tree_sub(state, block, 0);
1782			}
1783		}
1784		if (is_metadata) {
1785			if (!block->is_superblock) {
1786				if (num_pages * PAGE_SIZE <
1787				    state->metablock_size) {
1788					pr_info("btrfsic: cannot work with too short bios!\n");
1789					return;
1790				}
1791				processed_len = state->metablock_size;
1792				bytenr = btrfs_stack_header_bytenr(
1793						(struct btrfs_header *)
1794						mapped_datav[0]);
1795				btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
1796							       dev_state,
1797							       dev_bytenr);
1798			}
1799			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE) {
1800				if (block->logical_bytenr != bytenr &&
1801				    !(!block->is_metadata &&
1802				      block->logical_bytenr == 0))
1803					pr_info("Written block @%llu (%s/%llu/%d) found in hash table, %c, bytenr mismatch (!= stored %llu).\n",
1804					       bytenr, dev_state->name,
1805					       dev_bytenr,
1806					       block->mirror_num,
1807					       btrfsic_get_block_type(state,
1808								      block),
1809					       block->logical_bytenr);
1810				else
1811					pr_info("Written block @%llu (%s/%llu/%d) found in hash table, %c.\n",
1812					       bytenr, dev_state->name,
1813					       dev_bytenr, block->mirror_num,
1814					       btrfsic_get_block_type(state,
1815								      block));
1816			}
1817			block->logical_bytenr = bytenr;
1818		} else {
1819			if (num_pages * PAGE_SIZE <
1820			    state->datablock_size) {
1821				pr_info("btrfsic: cannot work with too short bios!\n");
1822				return;
1823			}
1824			processed_len = state->datablock_size;
1825			bytenr = block->logical_bytenr;
1826			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1827				pr_info("Written block @%llu (%s/%llu/%d) found in hash table, %c.\n",
1828				       bytenr, dev_state->name, dev_bytenr,
1829				       block->mirror_num,
1830				       btrfsic_get_block_type(state, block));
1831		}
1832
1833		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1834			pr_info("ref_to_list: %cE, ref_from_list: %cE\n",
1835			       list_empty(&block->ref_to_list) ? ' ' : '!',
1836			       list_empty(&block->ref_from_list) ? ' ' : '!');
1837		if (btrfsic_is_block_ref_by_superblock(state, block, 0)) {
1838			pr_info("btrfs: attempt to overwrite %c-block @%llu (%s/%llu/%d), old(gen=%llu, objectid=%llu, type=%d, offset=%llu), new(gen=%llu), which is referenced by most recent superblock (superblockgen=%llu)!\n",
1839			       btrfsic_get_block_type(state, block), bytenr,
1840			       dev_state->name, dev_bytenr, block->mirror_num,
1841			       block->generation,
1842			       btrfs_disk_key_objectid(&block->disk_key),
1843			       block->disk_key.type,
1844			       btrfs_disk_key_offset(&block->disk_key),
1845			       btrfs_stack_header_generation(
1846				       (struct btrfs_header *) mapped_datav[0]),
1847			       state->max_superblock_generation);
1848			btrfsic_dump_tree(state);
1849		}
1850
1851		if (!block->is_iodone && !block->never_written) {
1852			pr_info("btrfs: attempt to overwrite %c-block @%llu (%s/%llu/%d), oldgen=%llu, newgen=%llu, which is not yet iodone!\n",
1853			       btrfsic_get_block_type(state, block), bytenr,
1854			       dev_state->name, dev_bytenr, block->mirror_num,
1855			       block->generation,
1856			       btrfs_stack_header_generation(
1857				       (struct btrfs_header *)
1858				       mapped_datav[0]));
1859			/* it would not be safe to go on */
1860			btrfsic_dump_tree(state);
1861			goto continue_loop;
1862		}
1863
1864		/*
1865		 * Clear all references of this block. Do not free
1866		 * the block itself even if is not referenced anymore
1867		 * because it still carries valuable information
1868		 * like whether it was ever written and IO completed.
1869		 */
1870		list_for_each_entry_safe(l, tmp, &block->ref_to_list,
1871					 node_ref_to) {
1872			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1873				btrfsic_print_rem_link(state, l);
1874			l->ref_cnt--;
1875			if (0 == l->ref_cnt) {
1876				list_del(&l->node_ref_to);
1877				list_del(&l->node_ref_from);
1878				btrfsic_block_link_hashtable_remove(l);
1879				btrfsic_block_link_free(l);
1880			}
1881		}
1882
1883		block_ctx.dev = dev_state;
1884		block_ctx.dev_bytenr = dev_bytenr;
1885		block_ctx.start = bytenr;
1886		block_ctx.len = processed_len;
1887		block_ctx.pagev = NULL;
1888		block_ctx.mem_to_free = NULL;
1889		block_ctx.datav = mapped_datav;
1890
1891		if (is_metadata || state->include_extent_data) {
1892			block->never_written = 0;
1893			block->iodone_w_error = 0;
1894			if (NULL != bio) {
1895				block->is_iodone = 0;
1896				BUG_ON(NULL == bio_is_patched);
1897				if (!*bio_is_patched) {
1898					block->orig_bio_bh_private =
1899					    bio->bi_private;
1900					block->orig_bio_bh_end_io.bio =
1901					    bio->bi_end_io;
1902					block->next_in_same_bio = NULL;
1903					bio->bi_private = block;
1904					bio->bi_end_io = btrfsic_bio_end_io;
1905					*bio_is_patched = 1;
1906				} else {
1907					struct btrfsic_block *chained_block =
1908					    (struct btrfsic_block *)
1909					    bio->bi_private;
1910
1911					BUG_ON(NULL == chained_block);
1912					block->orig_bio_bh_private =
1913					    chained_block->orig_bio_bh_private;
1914					block->orig_bio_bh_end_io.bio =
1915					    chained_block->orig_bio_bh_end_io.
1916					    bio;
1917					block->next_in_same_bio = chained_block;
1918					bio->bi_private = block;
1919				}
1920			} else if (NULL != bh) {
1921				block->is_iodone = 0;
1922				block->orig_bio_bh_private = bh->b_private;
1923				block->orig_bio_bh_end_io.bh = bh->b_end_io;
1924				block->next_in_same_bio = NULL;
1925				bh->b_private = block;
1926				bh->b_end_io = btrfsic_bh_end_io;
1927			} else {
1928				block->is_iodone = 1;
1929				block->orig_bio_bh_private = NULL;
1930				block->orig_bio_bh_end_io.bio = NULL;
1931				block->next_in_same_bio = NULL;
1932			}
1933		}
1934
1935		block->flush_gen = dev_state->last_flush_gen + 1;
1936		block->submit_bio_bh_rw = submit_bio_bh_rw;
1937		if (is_metadata) {
1938			block->logical_bytenr = bytenr;
1939			block->is_metadata = 1;
1940			if (block->is_superblock) {
1941				BUG_ON(PAGE_SIZE !=
1942				       BTRFS_SUPER_INFO_SIZE);
1943				ret = btrfsic_process_written_superblock(
1944						state,
1945						block,
1946						(struct btrfs_super_block *)
1947						mapped_datav[0]);
1948				if (state->print_mask &
1949				    BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE) {
1950					pr_info("[after new superblock is written]:\n");
1951					btrfsic_dump_tree_sub(state, block, 0);
1952				}
1953			} else {
1954				block->mirror_num = 0;	/* unknown */
1955				ret = btrfsic_process_metablock(
1956						state,
1957						block,
1958						&block_ctx,
1959						0, 0);
1960			}
1961			if (ret)
1962				pr_info("btrfsic: btrfsic_process_metablock(root @%llu) failed!\n",
1963				       dev_bytenr);
1964		} else {
1965			block->is_metadata = 0;
1966			block->mirror_num = 0;	/* unknown */
1967			block->generation = BTRFSIC_GENERATION_UNKNOWN;
1968			if (!state->include_extent_data
1969			    && list_empty(&block->ref_from_list)) {
1970				/*
1971				 * disk block is overwritten with extent
1972				 * data (not meta data) and we are configured
1973				 * to not include extent data: take the
1974				 * chance and free the block's memory
1975				 */
1976				btrfsic_block_hashtable_remove(block);
1977				list_del(&block->all_blocks_node);
1978				btrfsic_block_free(block);
1979			}
1980		}
1981		btrfsic_release_block_ctx(&block_ctx);
1982	} else {
1983		/* block has not been found in hash table */
1984		u64 bytenr;
1985
1986		if (!is_metadata) {
1987			processed_len = state->datablock_size;
1988			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1989				pr_info("Written block (%s/%llu/?) !found in hash table, D.\n",
1990				       dev_state->name, dev_bytenr);
1991			if (!state->include_extent_data) {
1992				/* ignore that written D block */
1993				goto continue_loop;
1994			}
1995
1996			/* this is getting ugly for the
1997			 * include_extent_data case... */
1998			bytenr = 0;	/* unknown */
1999		} else {
2000			processed_len = state->metablock_size;
2001			bytenr = btrfs_stack_header_bytenr(
2002					(struct btrfs_header *)
2003					mapped_datav[0]);
2004			btrfsic_cmp_log_and_dev_bytenr(state, bytenr, dev_state,
2005						       dev_bytenr);
2006			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2007				pr_info("Written block @%llu (%s/%llu/?) !found in hash table, M.\n",
2008				       bytenr, dev_state->name, dev_bytenr);
2009		}
2010
2011		block_ctx.dev = dev_state;
2012		block_ctx.dev_bytenr = dev_bytenr;
2013		block_ctx.start = bytenr;
2014		block_ctx.len = processed_len;
2015		block_ctx.pagev = NULL;
2016		block_ctx.mem_to_free = NULL;
2017		block_ctx.datav = mapped_datav;
2018
2019		block = btrfsic_block_alloc();
2020		if (NULL == block) {
2021			pr_info("btrfsic: error, kmalloc failed!\n");
2022			btrfsic_release_block_ctx(&block_ctx);
2023			goto continue_loop;
2024		}
2025		block->dev_state = dev_state;
2026		block->dev_bytenr = dev_bytenr;
2027		block->logical_bytenr = bytenr;
2028		block->is_metadata = is_metadata;
2029		block->never_written = 0;
2030		block->iodone_w_error = 0;
2031		block->mirror_num = 0;	/* unknown */
2032		block->flush_gen = dev_state->last_flush_gen + 1;
2033		block->submit_bio_bh_rw = submit_bio_bh_rw;
2034		if (NULL != bio) {
2035			block->is_iodone = 0;
2036			BUG_ON(NULL == bio_is_patched);
2037			if (!*bio_is_patched) {
2038				block->orig_bio_bh_private = bio->bi_private;
2039				block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2040				block->next_in_same_bio = NULL;
2041				bio->bi_private = block;
2042				bio->bi_end_io = btrfsic_bio_end_io;
2043				*bio_is_patched = 1;
2044			} else {
2045				struct btrfsic_block *chained_block =
2046				    (struct btrfsic_block *)
2047				    bio->bi_private;
2048
2049				BUG_ON(NULL == chained_block);
2050				block->orig_bio_bh_private =
2051				    chained_block->orig_bio_bh_private;
2052				block->orig_bio_bh_end_io.bio =
2053				    chained_block->orig_bio_bh_end_io.bio;
2054				block->next_in_same_bio = chained_block;
2055				bio->bi_private = block;
2056			}
2057		} else if (NULL != bh) {
2058			block->is_iodone = 0;
2059			block->orig_bio_bh_private = bh->b_private;
2060			block->orig_bio_bh_end_io.bh = bh->b_end_io;
2061			block->next_in_same_bio = NULL;
2062			bh->b_private = block;
2063			bh->b_end_io = btrfsic_bh_end_io;
2064		} else {
2065			block->is_iodone = 1;
2066			block->orig_bio_bh_private = NULL;
2067			block->orig_bio_bh_end_io.bio = NULL;
2068			block->next_in_same_bio = NULL;
2069		}
2070		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2071			pr_info("New written %c-block @%llu (%s/%llu/%d)\n",
2072			       is_metadata ? 'M' : 'D',
2073			       block->logical_bytenr, block->dev_state->name,
2074			       block->dev_bytenr, block->mirror_num);
2075		list_add(&block->all_blocks_node, &state->all_blocks_list);
2076		btrfsic_block_hashtable_add(block, &state->block_hashtable);
2077
2078		if (is_metadata) {
2079			ret = btrfsic_process_metablock(state, block,
2080							&block_ctx, 0, 0);
2081			if (ret)
2082				pr_info("btrfsic: process_metablock(root @%llu) failed!\n",
2083				       dev_bytenr);
2084		}
2085		btrfsic_release_block_ctx(&block_ctx);
2086	}
2087
2088continue_loop:
2089	BUG_ON(!processed_len);
2090	dev_bytenr += processed_len;
2091	mapped_datav += processed_len >> PAGE_SHIFT;
2092	num_pages -= processed_len >> PAGE_SHIFT;
2093	goto again;
2094}
2095
2096static void btrfsic_bio_end_io(struct bio *bp)
2097{
2098	struct btrfsic_block *block = (struct btrfsic_block *)bp->bi_private;
2099	int iodone_w_error;
2100
2101	/* mutex is not held! This is not save if IO is not yet completed
2102	 * on umount */
2103	iodone_w_error = 0;
2104	if (bp->bi_status)
2105		iodone_w_error = 1;
2106
2107	BUG_ON(NULL == block);
2108	bp->bi_private = block->orig_bio_bh_private;
2109	bp->bi_end_io = block->orig_bio_bh_end_io.bio;
2110
2111	do {
2112		struct btrfsic_block *next_block;
2113		struct btrfsic_dev_state *const dev_state = block->dev_state;
2114
2115		if ((dev_state->state->print_mask &
2116		     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2117			pr_info("bio_end_io(err=%d) for %c @%llu (%s/%llu/%d)\n",
2118			       bp->bi_status,
2119			       btrfsic_get_block_type(dev_state->state, block),
2120			       block->logical_bytenr, dev_state->name,
2121			       block->dev_bytenr, block->mirror_num);
2122		next_block = block->next_in_same_bio;
2123		block->iodone_w_error = iodone_w_error;
2124		if (block->submit_bio_bh_rw & REQ_PREFLUSH) {
2125			dev_state->last_flush_gen++;
2126			if ((dev_state->state->print_mask &
2127			     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2128				pr_info("bio_end_io() new %s flush_gen=%llu\n",
2129				       dev_state->name,
2130				       dev_state->last_flush_gen);
2131		}
2132		if (block->submit_bio_bh_rw & REQ_FUA)
2133			block->flush_gen = 0; /* FUA completed means block is
2134					       * on disk */
2135		block->is_iodone = 1; /* for FLUSH, this releases the block */
2136		block = next_block;
2137	} while (NULL != block);
2138
2139	bp->bi_end_io(bp);
2140}
2141
2142static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate)
2143{
2144	struct btrfsic_block *block = (struct btrfsic_block *)bh->b_private;
2145	int iodone_w_error = !uptodate;
2146	struct btrfsic_dev_state *dev_state;
2147
2148	BUG_ON(NULL == block);
2149	dev_state = block->dev_state;
2150	if ((dev_state->state->print_mask & BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2151		pr_info("bh_end_io(error=%d) for %c @%llu (%s/%llu/%d)\n",
2152		       iodone_w_error,
2153		       btrfsic_get_block_type(dev_state->state, block),
2154		       block->logical_bytenr, block->dev_state->name,
2155		       block->dev_bytenr, block->mirror_num);
2156
2157	block->iodone_w_error = iodone_w_error;
2158	if (block->submit_bio_bh_rw & REQ_PREFLUSH) {
2159		dev_state->last_flush_gen++;
2160		if ((dev_state->state->print_mask &
2161		     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2162			pr_info("bh_end_io() new %s flush_gen=%llu\n",
2163			       dev_state->name, dev_state->last_flush_gen);
2164	}
2165	if (block->submit_bio_bh_rw & REQ_FUA)
2166		block->flush_gen = 0; /* FUA completed means block is on disk */
2167
2168	bh->b_private = block->orig_bio_bh_private;
2169	bh->b_end_io = block->orig_bio_bh_end_io.bh;
2170	block->is_iodone = 1; /* for FLUSH, this releases the block */
2171	bh->b_end_io(bh, uptodate);
2172}
2173
2174static int btrfsic_process_written_superblock(
2175		struct btrfsic_state *state,
2176		struct btrfsic_block *const superblock,
2177		struct btrfs_super_block *const super_hdr)
2178{
2179	struct btrfs_fs_info *fs_info = state->fs_info;
2180	int pass;
2181
2182	superblock->generation = btrfs_super_generation(super_hdr);
2183	if (!(superblock->generation > state->max_superblock_generation ||
2184	      0 == state->max_superblock_generation)) {
2185		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2186			pr_info("btrfsic: superblock @%llu (%s/%llu/%d) with old gen %llu <= %llu\n",
2187			       superblock->logical_bytenr,
2188			       superblock->dev_state->name,
2189			       superblock->dev_bytenr, superblock->mirror_num,
2190			       btrfs_super_generation(super_hdr),
2191			       state->max_superblock_generation);
2192	} else {
2193		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2194			pr_info("btrfsic: got new superblock @%llu (%s/%llu/%d) with new gen %llu > %llu\n",
2195			       superblock->logical_bytenr,
2196			       superblock->dev_state->name,
2197			       superblock->dev_bytenr, superblock->mirror_num,
2198			       btrfs_super_generation(super_hdr),
2199			       state->max_superblock_generation);
2200
2201		state->max_superblock_generation =
2202		    btrfs_super_generation(super_hdr);
2203		state->latest_superblock = superblock;
2204	}
2205
2206	for (pass = 0; pass < 3; pass++) {
2207		int ret;
2208		u64 next_bytenr;
2209		struct btrfsic_block *next_block;
2210		struct btrfsic_block_data_ctx tmp_next_block_ctx;
2211		struct btrfsic_block_link *l;
2212		int num_copies;
2213		int mirror_num;
2214		const char *additional_string = NULL;
2215		struct btrfs_disk_key tmp_disk_key = {0};
2216
2217		btrfs_set_disk_key_objectid(&tmp_disk_key,
2218					    BTRFS_ROOT_ITEM_KEY);
2219		btrfs_set_disk_key_objectid(&tmp_disk_key, 0);
2220
2221		switch (pass) {
2222		case 0:
2223			btrfs_set_disk_key_objectid(&tmp_disk_key,
2224						    BTRFS_ROOT_TREE_OBJECTID);
2225			additional_string = "root ";
2226			next_bytenr = btrfs_super_root(super_hdr);
2227			if (state->print_mask &
2228			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2229				pr_info("root@%llu\n", next_bytenr);
2230			break;
2231		case 1:
2232			btrfs_set_disk_key_objectid(&tmp_disk_key,
2233						    BTRFS_CHUNK_TREE_OBJECTID);
2234			additional_string = "chunk ";
2235			next_bytenr = btrfs_super_chunk_root(super_hdr);
2236			if (state->print_mask &
2237			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2238				pr_info("chunk@%llu\n", next_bytenr);
2239			break;
2240		case 2:
2241			btrfs_set_disk_key_objectid(&tmp_disk_key,
2242						    BTRFS_TREE_LOG_OBJECTID);
2243			additional_string = "log ";
2244			next_bytenr = btrfs_super_log_root(super_hdr);
2245			if (0 == next_bytenr)
2246				continue;
2247			if (state->print_mask &
2248			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2249				pr_info("log@%llu\n", next_bytenr);
2250			break;
2251		}
2252
2253		num_copies = btrfs_num_copies(fs_info, next_bytenr,
2254					      BTRFS_SUPER_INFO_SIZE);
2255		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
2256			pr_info("num_copies(log_bytenr=%llu) = %d\n",
2257			       next_bytenr, num_copies);
2258		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2259			int was_created;
2260
2261			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2262				pr_info("btrfsic_process_written_superblock(mirror_num=%d)\n", mirror_num);
2263			ret = btrfsic_map_block(state, next_bytenr,
2264						BTRFS_SUPER_INFO_SIZE,
2265						&tmp_next_block_ctx,
2266						mirror_num);
2267			if (ret) {
2268				pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
2269				       next_bytenr, mirror_num);
2270				return -1;
2271			}
2272
2273			next_block = btrfsic_block_lookup_or_add(
2274					state,
2275					&tmp_next_block_ctx,
2276					additional_string,
2277					1, 0, 1,
2278					mirror_num,
2279					&was_created);
2280			if (NULL == next_block) {
2281				pr_info("btrfsic: error, kmalloc failed!\n");
2282				btrfsic_release_block_ctx(&tmp_next_block_ctx);
2283				return -1;
2284			}
2285
2286			next_block->disk_key = tmp_disk_key;
2287			if (was_created)
2288				next_block->generation =
2289				    BTRFSIC_GENERATION_UNKNOWN;
2290			l = btrfsic_block_link_lookup_or_add(
2291					state,
2292					&tmp_next_block_ctx,
2293					next_block,
2294					superblock,
2295					BTRFSIC_GENERATION_UNKNOWN);
2296			btrfsic_release_block_ctx(&tmp_next_block_ctx);
2297			if (NULL == l)
2298				return -1;
2299		}
2300	}
2301
2302	if (WARN_ON(-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)))
2303		btrfsic_dump_tree(state);
2304
2305	return 0;
2306}
2307
2308static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
2309					struct btrfsic_block *const block,
2310					int recursion_level)
2311{
2312	const struct btrfsic_block_link *l;
2313	int ret = 0;
2314
2315	if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2316		/*
2317		 * Note that this situation can happen and does not
2318		 * indicate an error in regular cases. It happens
2319		 * when disk blocks are freed and later reused.
2320		 * The check-integrity module is not aware of any
2321		 * block free operations, it just recognizes block
2322		 * write operations. Therefore it keeps the linkage
2323		 * information for a block until a block is
2324		 * rewritten. This can temporarily cause incorrect
2325		 * and even circular linkage informations. This
2326		 * causes no harm unless such blocks are referenced
2327		 * by the most recent super block.
2328		 */
2329		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2330			pr_info("btrfsic: abort cyclic linkage (case 1).\n");
2331
2332		return ret;
2333	}
2334
2335	/*
2336	 * This algorithm is recursive because the amount of used stack
2337	 * space is very small and the max recursion depth is limited.
2338	 */
2339	list_for_each_entry(l, &block->ref_to_list, node_ref_to) {
2340		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2341			pr_info("rl=%d, %c @%llu (%s/%llu/%d) %u* refers to %c @%llu (%s/%llu/%d)\n",
2342			       recursion_level,
2343			       btrfsic_get_block_type(state, block),
2344			       block->logical_bytenr, block->dev_state->name,
2345			       block->dev_bytenr, block->mirror_num,
2346			       l->ref_cnt,
2347			       btrfsic_get_block_type(state, l->block_ref_to),
2348			       l->block_ref_to->logical_bytenr,
2349			       l->block_ref_to->dev_state->name,
2350			       l->block_ref_to->dev_bytenr,
2351			       l->block_ref_to->mirror_num);
2352		if (l->block_ref_to->never_written) {
2353			pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) which is never written!\n",
2354			       btrfsic_get_block_type(state, l->block_ref_to),
2355			       l->block_ref_to->logical_bytenr,
2356			       l->block_ref_to->dev_state->name,
2357			       l->block_ref_to->dev_bytenr,
2358			       l->block_ref_to->mirror_num);
2359			ret = -1;
2360		} else if (!l->block_ref_to->is_iodone) {
2361			pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) which is not yet iodone!\n",
2362			       btrfsic_get_block_type(state, l->block_ref_to),
2363			       l->block_ref_to->logical_bytenr,
2364			       l->block_ref_to->dev_state->name,
2365			       l->block_ref_to->dev_bytenr,
2366			       l->block_ref_to->mirror_num);
2367			ret = -1;
2368		} else if (l->block_ref_to->iodone_w_error) {
2369			pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) which has write error!\n",
2370			       btrfsic_get_block_type(state, l->block_ref_to),
2371			       l->block_ref_to->logical_bytenr,
2372			       l->block_ref_to->dev_state->name,
2373			       l->block_ref_to->dev_bytenr,
2374			       l->block_ref_to->mirror_num);
2375			ret = -1;
2376		} else if (l->parent_generation !=
2377			   l->block_ref_to->generation &&
2378			   BTRFSIC_GENERATION_UNKNOWN !=
2379			   l->parent_generation &&
2380			   BTRFSIC_GENERATION_UNKNOWN !=
2381			   l->block_ref_to->generation) {
2382			pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) with generation %llu != parent generation %llu!\n",
2383			       btrfsic_get_block_type(state, l->block_ref_to),
2384			       l->block_ref_to->logical_bytenr,
2385			       l->block_ref_to->dev_state->name,
2386			       l->block_ref_to->dev_bytenr,
2387			       l->block_ref_to->mirror_num,
2388			       l->block_ref_to->generation,
2389			       l->parent_generation);
2390			ret = -1;
2391		} else if (l->block_ref_to->flush_gen >
2392			   l->block_ref_to->dev_state->last_flush_gen) {
2393			pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) which is not flushed out of disk's write cache (block flush_gen=%llu, dev->flush_gen=%llu)!\n",
2394			       btrfsic_get_block_type(state, l->block_ref_to),
2395			       l->block_ref_to->logical_bytenr,
2396			       l->block_ref_to->dev_state->name,
2397			       l->block_ref_to->dev_bytenr,
2398			       l->block_ref_to->mirror_num, block->flush_gen,
2399			       l->block_ref_to->dev_state->last_flush_gen);
2400			ret = -1;
2401		} else if (-1 == btrfsic_check_all_ref_blocks(state,
2402							      l->block_ref_to,
2403							      recursion_level +
2404							      1)) {
2405			ret = -1;
2406		}
2407	}
2408
2409	return ret;
2410}
2411
2412static int btrfsic_is_block_ref_by_superblock(
2413		const struct btrfsic_state *state,
2414		const struct btrfsic_block *block,
2415		int recursion_level)
2416{
2417	const struct btrfsic_block_link *l;
2418
2419	if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2420		/* refer to comment at "abort cyclic linkage (case 1)" */
2421		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2422			pr_info("btrfsic: abort cyclic linkage (case 2).\n");
2423
2424		return 0;
2425	}
2426
2427	/*
2428	 * This algorithm is recursive because the amount of used stack space
2429	 * is very small and the max recursion depth is limited.
2430	 */
2431	list_for_each_entry(l, &block->ref_from_list, node_ref_from) {
2432		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2433			pr_info("rl=%d, %c @%llu (%s/%llu/%d) is ref %u* from %c @%llu (%s/%llu/%d)\n",
2434			       recursion_level,
2435			       btrfsic_get_block_type(state, block),
2436			       block->logical_bytenr, block->dev_state->name,
2437			       block->dev_bytenr, block->mirror_num,
2438			       l->ref_cnt,
2439			       btrfsic_get_block_type(state, l->block_ref_from),
2440			       l->block_ref_from->logical_bytenr,
2441			       l->block_ref_from->dev_state->name,
2442			       l->block_ref_from->dev_bytenr,
2443			       l->block_ref_from->mirror_num);
2444		if (l->block_ref_from->is_superblock &&
2445		    state->latest_superblock->dev_bytenr ==
2446		    l->block_ref_from->dev_bytenr &&
2447		    state->latest_superblock->dev_state->bdev ==
2448		    l->block_ref_from->dev_state->bdev)
2449			return 1;
2450		else if (btrfsic_is_block_ref_by_superblock(state,
2451							    l->block_ref_from,
2452							    recursion_level +
2453							    1))
2454			return 1;
2455	}
2456
2457	return 0;
2458}
2459
2460static void btrfsic_print_add_link(const struct btrfsic_state *state,
2461				   const struct btrfsic_block_link *l)
2462{
2463	pr_info("Add %u* link from %c @%llu (%s/%llu/%d) to %c @%llu (%s/%llu/%d).\n",
2464	       l->ref_cnt,
2465	       btrfsic_get_block_type(state, l->block_ref_from),
2466	       l->block_ref_from->logical_bytenr,
2467	       l->block_ref_from->dev_state->name,
2468	       l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2469	       btrfsic_get_block_type(state, l->block_ref_to),
2470	       l->block_ref_to->logical_bytenr,
2471	       l->block_ref_to->dev_state->name, l->block_ref_to->dev_bytenr,
2472	       l->block_ref_to->mirror_num);
2473}
2474
2475static void btrfsic_print_rem_link(const struct btrfsic_state *state,
2476				   const struct btrfsic_block_link *l)
2477{
2478	pr_info("Rem %u* link from %c @%llu (%s/%llu/%d) to %c @%llu (%s/%llu/%d).\n",
2479	       l->ref_cnt,
2480	       btrfsic_get_block_type(state, l->block_ref_from),
2481	       l->block_ref_from->logical_bytenr,
2482	       l->block_ref_from->dev_state->name,
2483	       l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2484	       btrfsic_get_block_type(state, l->block_ref_to),
2485	       l->block_ref_to->logical_bytenr,
2486	       l->block_ref_to->dev_state->name, l->block_ref_to->dev_bytenr,
2487	       l->block_ref_to->mirror_num);
2488}
2489
2490static char btrfsic_get_block_type(const struct btrfsic_state *state,
2491				   const struct btrfsic_block *block)
2492{
2493	if (block->is_superblock &&
2494	    state->latest_superblock->dev_bytenr == block->dev_bytenr &&
2495	    state->latest_superblock->dev_state->bdev == block->dev_state->bdev)
2496		return 'S';
2497	else if (block->is_superblock)
2498		return 's';
2499	else if (block->is_metadata)
2500		return 'M';
2501	else
2502		return 'D';
2503}
2504
2505static void btrfsic_dump_tree(const struct btrfsic_state *state)
2506{
2507	btrfsic_dump_tree_sub(state, state->latest_superblock, 0);
2508}
2509
2510static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
2511				  const struct btrfsic_block *block,
2512				  int indent_level)
2513{
2514	const struct btrfsic_block_link *l;
2515	int indent_add;
2516	static char buf[80];
2517	int cursor_position;
2518
2519	/*
2520	 * Should better fill an on-stack buffer with a complete line and
2521	 * dump it at once when it is time to print a newline character.
2522	 */
2523
2524	/*
2525	 * This algorithm is recursive because the amount of used stack space
2526	 * is very small and the max recursion depth is limited.
2527	 */
2528	indent_add = sprintf(buf, "%c-%llu(%s/%llu/%u)",
2529			     btrfsic_get_block_type(state, block),
2530			     block->logical_bytenr, block->dev_state->name,
2531			     block->dev_bytenr, block->mirror_num);
2532	if (indent_level + indent_add > BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2533		printk("[...]\n");
2534		return;
2535	}
2536	printk(buf);
2537	indent_level += indent_add;
2538	if (list_empty(&block->ref_to_list)) {
2539		printk("\n");
2540		return;
2541	}
2542	if (block->mirror_num > 1 &&
2543	    !(state->print_mask & BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS)) {
2544		printk(" [...]\n");
2545		return;
2546	}
2547
2548	cursor_position = indent_level;
2549	list_for_each_entry(l, &block->ref_to_list, node_ref_to) {
2550		while (cursor_position < indent_level) {
2551			printk(" ");
2552			cursor_position++;
2553		}
2554		if (l->ref_cnt > 1)
2555			indent_add = sprintf(buf, " %d*--> ", l->ref_cnt);
2556		else
2557			indent_add = sprintf(buf, " --> ");
2558		if (indent_level + indent_add >
2559		    BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2560			printk("[...]\n");
2561			cursor_position = 0;
2562			continue;
2563		}
2564
2565		printk(buf);
2566
2567		btrfsic_dump_tree_sub(state, l->block_ref_to,
2568				      indent_level + indent_add);
2569		cursor_position = 0;
2570	}
2571}
2572
2573static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
2574		struct btrfsic_state *state,
2575		struct btrfsic_block_data_ctx *next_block_ctx,
2576		struct btrfsic_block *next_block,
2577		struct btrfsic_block *from_block,
2578		u64 parent_generation)
2579{
2580	struct btrfsic_block_link *l;
2581
2582	l = btrfsic_block_link_hashtable_lookup(next_block_ctx->dev->bdev,
2583						next_block_ctx->dev_bytenr,
2584						from_block->dev_state->bdev,
2585						from_block->dev_bytenr,
2586						&state->block_link_hashtable);
2587	if (NULL == l) {
2588		l = btrfsic_block_link_alloc();
2589		if (NULL == l) {
2590			pr_info("btrfsic: error, kmalloc failed!\n");
2591			return NULL;
2592		}
2593
2594		l->block_ref_to = next_block;
2595		l->block_ref_from = from_block;
2596		l->ref_cnt = 1;
2597		l->parent_generation = parent_generation;
2598
2599		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2600			btrfsic_print_add_link(state, l);
2601
2602		list_add(&l->node_ref_to, &from_block->ref_to_list);
2603		list_add(&l->node_ref_from, &next_block->ref_from_list);
2604
2605		btrfsic_block_link_hashtable_add(l,
2606						 &state->block_link_hashtable);
2607	} else {
2608		l->ref_cnt++;
2609		l->parent_generation = parent_generation;
2610		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2611			btrfsic_print_add_link(state, l);
2612	}
2613
2614	return l;
2615}
2616
2617static struct btrfsic_block *btrfsic_block_lookup_or_add(
2618		struct btrfsic_state *state,
2619		struct btrfsic_block_data_ctx *block_ctx,
2620		const char *additional_string,
2621		int is_metadata,
2622		int is_iodone,
2623		int never_written,
2624		int mirror_num,
2625		int *was_created)
2626{
2627	struct btrfsic_block *block;
2628
2629	block = btrfsic_block_hashtable_lookup(block_ctx->dev->bdev,
2630					       block_ctx->dev_bytenr,
2631					       &state->block_hashtable);
2632	if (NULL == block) {
2633		struct btrfsic_dev_state *dev_state;
2634
2635		block = btrfsic_block_alloc();
2636		if (NULL == block) {
2637			pr_info("btrfsic: error, kmalloc failed!\n");
2638			return NULL;
2639		}
2640		dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev->bd_dev);
2641		if (NULL == dev_state) {
2642			pr_info("btrfsic: error, lookup dev_state failed!\n");
2643			btrfsic_block_free(block);
2644			return NULL;
2645		}
2646		block->dev_state = dev_state;
2647		block->dev_bytenr = block_ctx->dev_bytenr;
2648		block->logical_bytenr = block_ctx->start;
2649		block->is_metadata = is_metadata;
2650		block->is_iodone = is_iodone;
2651		block->never_written = never_written;
2652		block->mirror_num = mirror_num;
2653		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2654			pr_info("New %s%c-block @%llu (%s/%llu/%d)\n",
2655			       additional_string,
2656			       btrfsic_get_block_type(state, block),
2657			       block->logical_bytenr, dev_state->name,
2658			       block->dev_bytenr, mirror_num);
2659		list_add(&block->all_blocks_node, &state->all_blocks_list);
2660		btrfsic_block_hashtable_add(block, &state->block_hashtable);
2661		if (NULL != was_created)
2662			*was_created = 1;
2663	} else {
2664		if (NULL != was_created)
2665			*was_created = 0;
2666	}
2667
2668	return block;
2669}
2670
2671static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
2672					   u64 bytenr,
2673					   struct btrfsic_dev_state *dev_state,
2674					   u64 dev_bytenr)
2675{
2676	struct btrfs_fs_info *fs_info = state->fs_info;
2677	struct btrfsic_block_data_ctx block_ctx;
2678	int num_copies;
2679	int mirror_num;
2680	int match = 0;
2681	int ret;
2682
2683	num_copies = btrfs_num_copies(fs_info, bytenr, state->metablock_size);
2684
2685	for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2686		ret = btrfsic_map_block(state, bytenr, state->metablock_size,
2687					&block_ctx, mirror_num);
2688		if (ret) {
2689			pr_info("btrfsic: btrfsic_map_block(logical @%llu, mirror %d) failed!\n",
2690			       bytenr, mirror_num);
2691			continue;
2692		}
2693
2694		if (dev_state->bdev == block_ctx.dev->bdev &&
2695		    dev_bytenr == block_ctx.dev_bytenr) {
2696			match++;
2697			btrfsic_release_block_ctx(&block_ctx);
2698			break;
2699		}
2700		btrfsic_release_block_ctx(&block_ctx);
2701	}
2702
2703	if (WARN_ON(!match)) {
2704		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=%s, phys_bytenr=%llu)!\n",
2705		       bytenr, dev_state->name, dev_bytenr);
2706		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2707			ret = btrfsic_map_block(state, bytenr,
2708						state->metablock_size,
2709						&block_ctx, mirror_num);
2710			if (ret)
2711				continue;
2712
2713			pr_info("Read logical bytenr @%llu maps to (%s/%llu/%d)\n",
2714			       bytenr, block_ctx.dev->name,
2715			       block_ctx.dev_bytenr, mirror_num);
2716		}
2717	}
2718}
2719
2720static struct btrfsic_dev_state *btrfsic_dev_state_lookup(dev_t dev)
2721{
2722	return btrfsic_dev_state_hashtable_lookup(dev,
2723						  &btrfsic_dev_state_hashtable);
2724}
2725
2726int btrfsic_submit_bh(int op, int op_flags, struct buffer_head *bh)
2727{
2728	struct btrfsic_dev_state *dev_state;
2729
2730	if (!btrfsic_is_initialized)
2731		return submit_bh(op, op_flags, bh);
2732
2733	mutex_lock(&btrfsic_mutex);
2734	/* since btrfsic_submit_bh() might also be called before
2735	 * btrfsic_mount(), this might return NULL */
2736	dev_state = btrfsic_dev_state_lookup(bh->b_bdev->bd_dev);
2737
2738	/* Only called to write the superblock (incl. FLUSH/FUA) */
2739	if (NULL != dev_state &&
2740	    (op == REQ_OP_WRITE) && bh->b_size > 0) {
2741		u64 dev_bytenr;
2742
2743		dev_bytenr = BTRFS_BDEV_BLOCKSIZE * bh->b_blocknr;
2744		if (dev_state->state->print_mask &
2745		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2746			pr_info("submit_bh(op=0x%x,0x%x, blocknr=%llu (bytenr %llu), size=%zu, data=%p, bdev=%p)\n",
2747			       op, op_flags, (unsigned long long)bh->b_blocknr,
2748			       dev_bytenr, bh->b_size, bh->b_data, bh->b_bdev);
2749		btrfsic_process_written_block(dev_state, dev_bytenr,
2750					      &bh->b_data, 1, NULL,
2751					      NULL, bh, op_flags);
2752	} else if (NULL != dev_state && (op_flags & REQ_PREFLUSH)) {
2753		if (dev_state->state->print_mask &
2754		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2755			pr_info("submit_bh(op=0x%x,0x%x FLUSH, bdev=%p)\n",
2756			       op, op_flags, bh->b_bdev);
2757		if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
2758			if ((dev_state->state->print_mask &
2759			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2760			      BTRFSIC_PRINT_MASK_VERBOSE)))
2761				pr_info("btrfsic_submit_bh(%s) with FLUSH but dummy block already in use (ignored)!\n",
2762				       dev_state->name);
2763		} else {
2764			struct btrfsic_block *const block =
2765				&dev_state->dummy_block_for_bio_bh_flush;
2766
2767			block->is_iodone = 0;
2768			block->never_written = 0;
2769			block->iodone_w_error = 0;
2770			block->flush_gen = dev_state->last_flush_gen + 1;
2771			block->submit_bio_bh_rw = op_flags;
2772			block->orig_bio_bh_private = bh->b_private;
2773			block->orig_bio_bh_end_io.bh = bh->b_end_io;
2774			block->next_in_same_bio = NULL;
2775			bh->b_private = block;
2776			bh->b_end_io = btrfsic_bh_end_io;
2777		}
2778	}
2779	mutex_unlock(&btrfsic_mutex);
2780	return submit_bh(op, op_flags, bh);
2781}
2782
2783static void __btrfsic_submit_bio(struct bio *bio)
2784{
2785	struct btrfsic_dev_state *dev_state;
2786
2787	if (!btrfsic_is_initialized)
2788		return;
2789
2790	mutex_lock(&btrfsic_mutex);
2791	/* since btrfsic_submit_bio() is also called before
2792	 * btrfsic_mount(), this might return NULL */
2793	dev_state = btrfsic_dev_state_lookup(bio_dev(bio) + bio->bi_partno);
2794	if (NULL != dev_state &&
2795	    (bio_op(bio) == REQ_OP_WRITE) && bio_has_data(bio)) {
2796		unsigned int i = 0;
2797		u64 dev_bytenr;
2798		u64 cur_bytenr;
2799		struct bio_vec bvec;
2800		struct bvec_iter iter;
2801		int bio_is_patched;
2802		char **mapped_datav;
2803		unsigned int segs = bio_segments(bio);
2804
2805		dev_bytenr = 512 * bio->bi_iter.bi_sector;
2806		bio_is_patched = 0;
2807		if (dev_state->state->print_mask &
2808		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2809			pr_info("submit_bio(rw=%d,0x%x, bi_vcnt=%u, bi_sector=%llu (bytenr %llu), bi_disk=%p)\n",
2810			       bio_op(bio), bio->bi_opf, segs,
2811			       (unsigned long long)bio->bi_iter.bi_sector,
2812			       dev_bytenr, bio->bi_disk);
2813
2814		mapped_datav = kmalloc_array(segs,
2815					     sizeof(*mapped_datav), GFP_NOFS);
2816		if (!mapped_datav)
2817			goto leave;
2818		cur_bytenr = dev_bytenr;
2819
2820		bio_for_each_segment(bvec, bio, iter) {
2821			BUG_ON(bvec.bv_len != PAGE_SIZE);
2822			mapped_datav[i] = kmap(bvec.bv_page);
2823			i++;
2824
2825			if (dev_state->state->print_mask &
2826			    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE)
2827				pr_info("#%u: bytenr=%llu, len=%u, offset=%u\n",
2828				       i, cur_bytenr, bvec.bv_len, bvec.bv_offset);
2829			cur_bytenr += bvec.bv_len;
2830		}
2831		btrfsic_process_written_block(dev_state, dev_bytenr,
2832					      mapped_datav, segs,
2833					      bio, &bio_is_patched,
2834					      NULL, bio->bi_opf);
2835		bio_for_each_segment(bvec, bio, iter)
2836			kunmap(bvec.bv_page);
2837		kfree(mapped_datav);
2838	} else if (NULL != dev_state && (bio->bi_opf & REQ_PREFLUSH)) {
2839		if (dev_state->state->print_mask &
2840		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2841			pr_info("submit_bio(rw=%d,0x%x FLUSH, disk=%p)\n",
2842			       bio_op(bio), bio->bi_opf, bio->bi_disk);
2843		if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
2844			if ((dev_state->state->print_mask &
2845			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2846			      BTRFSIC_PRINT_MASK_VERBOSE)))
2847				pr_info("btrfsic_submit_bio(%s) with FLUSH but dummy block already in use (ignored)!\n",
2848				       dev_state->name);
2849		} else {
2850			struct btrfsic_block *const block =
2851				&dev_state->dummy_block_for_bio_bh_flush;
2852
2853			block->is_iodone = 0;
2854			block->never_written = 0;
2855			block->iodone_w_error = 0;
2856			block->flush_gen = dev_state->last_flush_gen + 1;
2857			block->submit_bio_bh_rw = bio->bi_opf;
2858			block->orig_bio_bh_private = bio->bi_private;
2859			block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2860			block->next_in_same_bio = NULL;
2861			bio->bi_private = block;
2862			bio->bi_end_io = btrfsic_bio_end_io;
2863		}
2864	}
2865leave:
2866	mutex_unlock(&btrfsic_mutex);
2867}
2868
2869void btrfsic_submit_bio(struct bio *bio)
2870{
2871	__btrfsic_submit_bio(bio);
2872	submit_bio(bio);
2873}
2874
2875int btrfsic_submit_bio_wait(struct bio *bio)
2876{
2877	__btrfsic_submit_bio(bio);
2878	return submit_bio_wait(bio);
2879}
2880
2881int btrfsic_mount(struct btrfs_fs_info *fs_info,
2882		  struct btrfs_fs_devices *fs_devices,
2883		  int including_extent_data, u32 print_mask)
2884{
2885	int ret;
2886	struct btrfsic_state *state;
2887	struct list_head *dev_head = &fs_devices->devices;
2888	struct btrfs_device *device;
2889
2890	if (fs_info->nodesize & ((u64)PAGE_SIZE - 1)) {
2891		pr_info("btrfsic: cannot handle nodesize %d not being a multiple of PAGE_SIZE %ld!\n",
2892		       fs_info->nodesize, PAGE_SIZE);
2893		return -1;
2894	}
2895	if (fs_info->sectorsize & ((u64)PAGE_SIZE - 1)) {
2896		pr_info("btrfsic: cannot handle sectorsize %d not being a multiple of PAGE_SIZE %ld!\n",
2897		       fs_info->sectorsize, PAGE_SIZE);
2898		return -1;
2899	}
2900	state = kvzalloc(sizeof(*state), GFP_KERNEL);
2901	if (!state) {
2902		pr_info("btrfs check-integrity: allocation failed!\n");
2903		return -ENOMEM;
2904	}
2905
2906	if (!btrfsic_is_initialized) {
2907		mutex_init(&btrfsic_mutex);
2908		btrfsic_dev_state_hashtable_init(&btrfsic_dev_state_hashtable);
2909		btrfsic_is_initialized = 1;
2910	}
2911	mutex_lock(&btrfsic_mutex);
2912	state->fs_info = fs_info;
2913	state->print_mask = print_mask;
2914	state->include_extent_data = including_extent_data;
2915	state->csum_size = 0;
2916	state->metablock_size = fs_info->nodesize;
2917	state->datablock_size = fs_info->sectorsize;
2918	INIT_LIST_HEAD(&state->all_blocks_list);
2919	btrfsic_block_hashtable_init(&state->block_hashtable);
2920	btrfsic_block_link_hashtable_init(&state->block_link_hashtable);
2921	state->max_superblock_generation = 0;
2922	state->latest_superblock = NULL;
2923
2924	list_for_each_entry(device, dev_head, dev_list) {
2925		struct btrfsic_dev_state *ds;
2926		const char *p;
2927
2928		if (!device->bdev || !device->name)
2929			continue;
2930
2931		ds = btrfsic_dev_state_alloc();
2932		if (NULL == ds) {
2933			pr_info("btrfs check-integrity: kmalloc() failed!\n");
2934			mutex_unlock(&btrfsic_mutex);
2935			return -ENOMEM;
2936		}
2937		ds->bdev = device->bdev;
2938		ds->state = state;
2939		bdevname(ds->bdev, ds->name);
2940		ds->name[BDEVNAME_SIZE - 1] = '\0';
2941		p = kbasename(ds->name);
2942		strlcpy(ds->name, p, sizeof(ds->name));
2943		btrfsic_dev_state_hashtable_add(ds,
2944						&btrfsic_dev_state_hashtable);
2945	}
2946
2947	ret = btrfsic_process_superblock(state, fs_devices);
2948	if (0 != ret) {
2949		mutex_unlock(&btrfsic_mutex);
2950		btrfsic_unmount(fs_devices);
2951		return ret;
2952	}
2953
2954	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_DATABASE)
2955		btrfsic_dump_database(state);
2956	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_TREE)
2957		btrfsic_dump_tree(state);
2958
2959	mutex_unlock(&btrfsic_mutex);
2960	return 0;
2961}
2962
2963void btrfsic_unmount(struct btrfs_fs_devices *fs_devices)
2964{
2965	struct btrfsic_block *b_all, *tmp_all;
2966	struct btrfsic_state *state;
2967	struct list_head *dev_head = &fs_devices->devices;
2968	struct btrfs_device *device;
2969
2970	if (!btrfsic_is_initialized)
2971		return;
2972
2973	mutex_lock(&btrfsic_mutex);
2974
2975	state = NULL;
2976	list_for_each_entry(device, dev_head, dev_list) {
2977		struct btrfsic_dev_state *ds;
2978
2979		if (!device->bdev || !device->name)
2980			continue;
2981
2982		ds = btrfsic_dev_state_hashtable_lookup(
2983				device->bdev->bd_dev,
2984				&btrfsic_dev_state_hashtable);
2985		if (NULL != ds) {
2986			state = ds->state;
2987			btrfsic_dev_state_hashtable_remove(ds);
2988			btrfsic_dev_state_free(ds);
2989		}
2990	}
2991
2992	if (NULL == state) {
2993		pr_info("btrfsic: error, cannot find state information on umount!\n");
2994		mutex_unlock(&btrfsic_mutex);
2995		return;
2996	}
2997
2998	/*
2999	 * Don't care about keeping the lists' state up to date,
3000	 * just free all memory that was allocated dynamically.
3001	 * Free the blocks and the block_links.
3002	 */
3003	list_for_each_entry_safe(b_all, tmp_all, &state->all_blocks_list,
3004				 all_blocks_node) {
3005		struct btrfsic_block_link *l, *tmp;
3006
3007		list_for_each_entry_safe(l, tmp, &b_all->ref_to_list,
3008					 node_ref_to) {
3009			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
3010				btrfsic_print_rem_link(state, l);
3011
3012			l->ref_cnt--;
3013			if (0 == l->ref_cnt)
3014				btrfsic_block_link_free(l);
3015		}
3016
3017		if (b_all->is_iodone || b_all->never_written)
3018			btrfsic_block_free(b_all);
3019		else
3020			pr_info("btrfs: attempt to free %c-block @%llu (%s/%llu/%d) on umount which is not yet iodone!\n",
3021			       btrfsic_get_block_type(state, b_all),
3022			       b_all->logical_bytenr, b_all->dev_state->name,
3023			       b_all->dev_bytenr, b_all->mirror_num);
3024	}
3025
3026	mutex_unlock(&btrfsic_mutex);
3027
3028	kvfree(state);
3029}