1/*
   2 * Copyright (C) STRATO AG 2011.  All rights reserved.
   3 *
   4 * This program is free software; you can redistribute it and/or
   5 * modify it under the terms of the GNU General Public
   6 * License v2 as published by the Free Software Foundation.
   7 *
   8 * This program is distributed in the hope that it will be useful,
   9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11 * General Public License for more details.
  12 *
  13 * You should have received a copy of the GNU General Public
  14 * License along with this program; if not, write to the
  15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16 * Boston, MA 021110-1307, USA.
  17 */
  18
  19/*
  20 * This module can be used to catch cases when the btrfs kernel
  21 * code executes write requests to the disk that bring the file
  22 * system in an inconsistent state. In such a state, a power-loss
  23 * or kernel panic event would cause that the data on disk is
  24 * lost or at least damaged.
  25 *
  26 * Code is added that examines all block write requests during
  27 * runtime (including writes of the super block). Three rules
  28 * are verified and an error is printed on violation of the
  29 * rules:
  30 * 1. It is not allowed to write a disk block which is
  31 *    currently referenced by the super block (either directly
  32 *    or indirectly).
  33 * 2. When a super block is written, it is verified that all
  34 *    referenced (directly or indirectly) blocks fulfill the
  35 *    following requirements:
  36 *    2a. All referenced blocks have either been present when
  37 *        the file system was mounted, (i.e., they have been
  38 *        referenced by the super block) or they have been
  39 *        written since then and the write completion callback
  40 *        was called and no write error was indicated and a
  41 *        FLUSH request to the device where these blocks are
  42 *        located was received and completed.
  43 *    2b. All referenced blocks need to have a generation
  44 *        number which is equal to the parent's number.
  45 *
  46 * One issue that was found using this module was that the log
  47 * tree on disk became temporarily corrupted because disk blocks
  48 * that had been in use for the log tree had been freed and
  49 * reused too early, while being referenced by the written super
  50 * block.
  51 *
  52 * The search term in the kernel log that can be used to filter
  53 * on the existence of detected integrity issues is
  54 * "btrfs: attempt".
  55 *
  56 * The integrity check is enabled via mount options. These
  57 * mount options are only supported if the integrity check
  58 * tool is compiled by defining BTRFS_FS_CHECK_INTEGRITY.
  59 *
  60 * Example #1, apply integrity checks to all metadata:
  61 * mount /dev/sdb1 /mnt -o check_int
  62 *
  63 * Example #2, apply integrity checks to all metadata and
  64 * to data extents:
  65 * mount /dev/sdb1 /mnt -o check_int_data
  66 *
  67 * Example #3, apply integrity checks to all metadata and dump
  68 * the tree that the super block references to kernel messages
  69 * each time after a super block was written:
  70 * mount /dev/sdb1 /mnt -o check_int,check_int_print_mask=263
  71 *
  72 * If the integrity check tool is included and activated in
  73 * the mount options, plenty of kernel memory is used, and
  74 * plenty of additional CPU cycles are spent. Enabling this
  75 * functionality is not intended for normal use. In most
  76 * cases, unless you are a btrfs developer who needs to verify
  77 * the integrity of (super)-block write requests, do not
  78 * enable the config option BTRFS_FS_CHECK_INTEGRITY to
  79 * include and compile the integrity check tool.
  80 *
  81 * Expect millions of lines of information in the kernel log with an
  82 * enabled check_int_print_mask. Therefore set LOG_BUF_SHIFT in the
  83 * kernel config to at least 26 (which is 64MB). Usually the value is
  84 * limited to 21 (which is 2MB) in init/Kconfig. The file needs to be
  85 * changed like this before LOG_BUF_SHIFT can be set to a high value:
  86 * config LOG_BUF_SHIFT
  87 *       int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
  88 *       range 12 30
  89 */
  90
  91#include <linux/sched.h>
  92#include <linux/slab.h>
  93#include <linux/buffer_head.h>
  94#include <linux/mutex.h>
  95#include <linux/genhd.h>
  96#include <linux/blkdev.h>
  97#include "ctree.h"
  98#include "disk-io.h"
  99#include "hash.h"
 100#include "transaction.h"
 101#include "extent_io.h"
 102#include "volumes.h"
 103#include "print-tree.h"
 104#include "locking.h"
 105#include "check-integrity.h"
 106#include "rcu-string.h"
 107
 108#define BTRFSIC_BLOCK_HASHTABLE_SIZE 0x10000
 109#define BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE 0x10000
 110#define BTRFSIC_DEV2STATE_HASHTABLE_SIZE 0x100
 111#define BTRFSIC_BLOCK_MAGIC_NUMBER 0x14491051
 112#define BTRFSIC_BLOCK_LINK_MAGIC_NUMBER 0x11070807
 113#define BTRFSIC_DEV2STATE_MAGIC_NUMBER 0x20111530
 114#define BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER 20111300
 115#define BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL (200 - 6)	/* in characters,
 116							 * excluding " [...]" */
 117#define BTRFSIC_GENERATION_UNKNOWN ((u64)-1)
 118
 119/*
 120 * The definition of the bitmask fields for the print_mask.
 121 * They are specified with the mount option check_integrity_print_mask.
 122 */
 123#define BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE			0x00000001
 124#define BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION		0x00000002
 125#define BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE			0x00000004
 126#define BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE			0x00000008
 127#define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH			0x00000010
 128#define BTRFSIC_PRINT_MASK_END_IO_BIO_BH			0x00000020
 129#define BTRFSIC_PRINT_MASK_VERBOSE				0x00000040
 130#define BTRFSIC_PRINT_MASK_VERY_VERBOSE				0x00000080
 131#define BTRFSIC_PRINT_MASK_INITIAL_TREE				0x00000100
 132#define BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES			0x00000200
 133#define BTRFSIC_PRINT_MASK_INITIAL_DATABASE			0x00000400
 134#define BTRFSIC_PRINT_MASK_NUM_COPIES				0x00000800
 135#define BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS		0x00001000
 136#define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE		0x00002000
 137
 138struct btrfsic_dev_state;
 139struct btrfsic_state;
 140
 141struct btrfsic_block {
 142	u32 magic_num;		/* only used for debug purposes */
 143	unsigned int is_metadata:1;	/* if it is meta-data, not data-data */
 144	unsigned int is_superblock:1;	/* if it is one of the superblocks */
 145	unsigned int is_iodone:1;	/* if is done by lower subsystem */
 146	unsigned int iodone_w_error:1;	/* error was indicated to endio */
 147	unsigned int never_written:1;	/* block was added because it was
 148					 * referenced, not because it was
 149					 * written */
 150	unsigned int mirror_num;	/* large enough to hold
 151					 * BTRFS_SUPER_MIRROR_MAX */
 152	struct btrfsic_dev_state *dev_state;
 153	u64 dev_bytenr;		/* key, physical byte num on disk */
 154	u64 logical_bytenr;	/* logical byte num on disk */
 155	u64 generation;
 156	struct btrfs_disk_key disk_key;	/* extra info to print in case of
 157					 * issues, will not always be correct */
 158	struct list_head collision_resolving_node;	/* list node */
 159	struct list_head all_blocks_node;	/* list node */
 160
 161	/* the following two lists contain block_link items */
 162	struct list_head ref_to_list;	/* list */
 163	struct list_head ref_from_list;	/* list */
 164	struct btrfsic_block *next_in_same_bio;
 165	void *orig_bio_bh_private;
 166	union {
 167		bio_end_io_t *bio;
 168		bh_end_io_t *bh;
 169	} orig_bio_bh_end_io;
 170	int submit_bio_bh_rw;
 171	u64 flush_gen; /* only valid if !never_written */
 172};
 173
 174/*
 175 * Elements of this type are allocated dynamically and required because
 176 * each block object can refer to and can be ref from multiple blocks.
 177 * The key to lookup them in the hashtable is the dev_bytenr of
 178 * the block ref to plus the one from the block refered from.
 179 * The fact that they are searchable via a hashtable and that a
 180 * ref_cnt is maintained is not required for the btrfs integrity
 181 * check algorithm itself, it is only used to make the output more
 182 * beautiful in case that an error is detected (an error is defined
 183 * as a write operation to a block while that block is still referenced).
 184 */
 185struct btrfsic_block_link {
 186	u32 magic_num;		/* only used for debug purposes */
 187	u32 ref_cnt;
 188	struct list_head node_ref_to;	/* list node */
 189	struct list_head node_ref_from;	/* list node */
 190	struct list_head collision_resolving_node;	/* list node */
 191	struct btrfsic_block *block_ref_to;
 192	struct btrfsic_block *block_ref_from;
 193	u64 parent_generation;
 194};
 195
 196struct btrfsic_dev_state {
 197	u32 magic_num;		/* only used for debug purposes */
 198	struct block_device *bdev;
 199	struct btrfsic_state *state;
 200	struct list_head collision_resolving_node;	/* list node */
 201	struct btrfsic_block dummy_block_for_bio_bh_flush;
 202	u64 last_flush_gen;
 203	char name[BDEVNAME_SIZE];
 204};
 205
 206struct btrfsic_block_hashtable {
 207	struct list_head table[BTRFSIC_BLOCK_HASHTABLE_SIZE];
 208};
 209
 210struct btrfsic_block_link_hashtable {
 211	struct list_head table[BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE];
 212};
 213
 214struct btrfsic_dev_state_hashtable {
 215	struct list_head table[BTRFSIC_DEV2STATE_HASHTABLE_SIZE];
 216};
 217
 218struct btrfsic_block_data_ctx {
 219	u64 start;		/* virtual bytenr */
 220	u64 dev_bytenr;		/* physical bytenr on device */
 221	u32 len;
 222	struct btrfsic_dev_state *dev;
 223	char **datav;
 224	struct page **pagev;
 225	void *mem_to_free;
 226};
 227
 228/* This structure is used to implement recursion without occupying
 229 * any stack space, refer to btrfsic_process_metablock() */
 230struct btrfsic_stack_frame {
 231	u32 magic;
 232	u32 nr;
 233	int error;
 234	int i;
 235	int limit_nesting;
 236	int num_copies;
 237	int mirror_num;
 238	struct btrfsic_block *block;
 239	struct btrfsic_block_data_ctx *block_ctx;
 240	struct btrfsic_block *next_block;
 241	struct btrfsic_block_data_ctx next_block_ctx;
 242	struct btrfs_header *hdr;
 243	struct btrfsic_stack_frame *prev;
 244};
 245
 246/* Some state per mounted filesystem */
 247struct btrfsic_state {
 248	u32 print_mask;
 249	int include_extent_data;
 250	int csum_size;
 251	struct list_head all_blocks_list;
 252	struct btrfsic_block_hashtable block_hashtable;
 253	struct btrfsic_block_link_hashtable block_link_hashtable;
 254	struct btrfs_root *root;
 255	u64 max_superblock_generation;
 256	struct btrfsic_block *latest_superblock;
 257	u32 metablock_size;
 258	u32 datablock_size;
 259};
 260
 261static void btrfsic_block_init(struct btrfsic_block *b);
 262static struct btrfsic_block *btrfsic_block_alloc(void);
 263static void btrfsic_block_free(struct btrfsic_block *b);
 264static void btrfsic_block_link_init(struct btrfsic_block_link *n);
 265static struct btrfsic_block_link *btrfsic_block_link_alloc(void);
 266static void btrfsic_block_link_free(struct btrfsic_block_link *n);
 267static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds);
 268static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void);
 269static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds);
 270static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h);
 271static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
 272					struct btrfsic_block_hashtable *h);
 273static void btrfsic_block_hashtable_remove(struct btrfsic_block *b);
 274static struct btrfsic_block *btrfsic_block_hashtable_lookup(
 275		struct block_device *bdev,
 276		u64 dev_bytenr,
 277		struct btrfsic_block_hashtable *h);
 278static void btrfsic_block_link_hashtable_init(
 279		struct btrfsic_block_link_hashtable *h);
 280static void btrfsic_block_link_hashtable_add(
 281		struct btrfsic_block_link *l,
 282		struct btrfsic_block_link_hashtable *h);
 283static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l);
 284static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
 285		struct block_device *bdev_ref_to,
 286		u64 dev_bytenr_ref_to,
 287		struct block_device *bdev_ref_from,
 288		u64 dev_bytenr_ref_from,
 289		struct btrfsic_block_link_hashtable *h);
 290static void btrfsic_dev_state_hashtable_init(
 291		struct btrfsic_dev_state_hashtable *h);
 292static void btrfsic_dev_state_hashtable_add(
 293		struct btrfsic_dev_state *ds,
 294		struct btrfsic_dev_state_hashtable *h);
 295static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds);
 296static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
 297		struct block_device *bdev,
 298		struct btrfsic_dev_state_hashtable *h);
 299static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void);
 300static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf);
 301static int btrfsic_process_superblock(struct btrfsic_state *state,
 302				      struct btrfs_fs_devices *fs_devices);
 303static int btrfsic_process_metablock(struct btrfsic_state *state,
 304				     struct btrfsic_block *block,
 305				     struct btrfsic_block_data_ctx *block_ctx,
 306				     int limit_nesting, int force_iodone_flag);
 307static void btrfsic_read_from_block_data(
 308	struct btrfsic_block_data_ctx *block_ctx,
 309	void *dst, u32 offset, size_t len);
 310static int btrfsic_create_link_to_next_block(
 311		struct btrfsic_state *state,
 312		struct btrfsic_block *block,
 313		struct btrfsic_block_data_ctx
 314		*block_ctx, u64 next_bytenr,
 315		int limit_nesting,
 316		struct btrfsic_block_data_ctx *next_block_ctx,
 317		struct btrfsic_block **next_blockp,
 318		int force_iodone_flag,
 319		int *num_copiesp, int *mirror_nump,
 320		struct btrfs_disk_key *disk_key,
 321		u64 parent_generation);
 322static int btrfsic_handle_extent_data(struct btrfsic_state *state,
 323				      struct btrfsic_block *block,
 324				      struct btrfsic_block_data_ctx *block_ctx,
 325				      u32 item_offset, int force_iodone_flag);
 326static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
 327			     struct btrfsic_block_data_ctx *block_ctx_out,
 328			     int mirror_num);
 329static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
 330				  u32 len, struct block_device *bdev,
 331				  struct btrfsic_block_data_ctx *block_ctx_out);
 332static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx);
 333static int btrfsic_read_block(struct btrfsic_state *state,
 334			      struct btrfsic_block_data_ctx *block_ctx);
 335static void btrfsic_dump_database(struct btrfsic_state *state);
 336static int btrfsic_test_for_metadata(struct btrfsic_state *state,
 337				     char **datav, unsigned int num_pages);
 338static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
 339					  u64 dev_bytenr, char **mapped_datav,
 340					  unsigned int num_pages,
 341					  struct bio *bio, int *bio_is_patched,
 342					  struct buffer_head *bh,
 343					  int submit_bio_bh_rw);
 344static int btrfsic_process_written_superblock(
 345		struct btrfsic_state *state,
 346		struct btrfsic_block *const block,
 347		struct btrfs_super_block *const super_hdr);
 348static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status);
 349static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate);
 350static int btrfsic_is_block_ref_by_superblock(const struct btrfsic_state *state,
 351					      const struct btrfsic_block *block,
 352					      int recursion_level);
 353static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
 354					struct btrfsic_block *const block,
 355					int recursion_level);
 356static void btrfsic_print_add_link(const struct btrfsic_state *state,
 357				   const struct btrfsic_block_link *l);
 358static void btrfsic_print_rem_link(const struct btrfsic_state *state,
 359				   const struct btrfsic_block_link *l);
 360static char btrfsic_get_block_type(const struct btrfsic_state *state,
 361				   const struct btrfsic_block *block);
 362static void btrfsic_dump_tree(const struct btrfsic_state *state);
 363static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
 364				  const struct btrfsic_block *block,
 365				  int indent_level);
 366static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
 367		struct btrfsic_state *state,
 368		struct btrfsic_block_data_ctx *next_block_ctx,
 369		struct btrfsic_block *next_block,
 370		struct btrfsic_block *from_block,
 371		u64 parent_generation);
 372static struct btrfsic_block *btrfsic_block_lookup_or_add(
 373		struct btrfsic_state *state,
 374		struct btrfsic_block_data_ctx *block_ctx,
 375		const char *additional_string,
 376		int is_metadata,
 377		int is_iodone,
 378		int never_written,
 379		int mirror_num,
 380		int *was_created);
 381static int btrfsic_process_superblock_dev_mirror(
 382		struct btrfsic_state *state,
 383		struct btrfsic_dev_state *dev_state,
 384		struct btrfs_device *device,
 385		int superblock_mirror_num,
 386		struct btrfsic_dev_state **selected_dev_state,
 387		struct btrfs_super_block *selected_super);
 388static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
 389		struct block_device *bdev);
 390static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
 391					   u64 bytenr,
 392					   struct btrfsic_dev_state *dev_state,
 393					   u64 dev_bytenr);
 394
 395static struct mutex btrfsic_mutex;
 396static int btrfsic_is_initialized;
 397static struct btrfsic_dev_state_hashtable btrfsic_dev_state_hashtable;
 398
 399
 400static void btrfsic_block_init(struct btrfsic_block *b)
 401{
 402	b->magic_num = BTRFSIC_BLOCK_MAGIC_NUMBER;
 403	b->dev_state = NULL;
 404	b->dev_bytenr = 0;
 405	b->logical_bytenr = 0;
 406	b->generation = BTRFSIC_GENERATION_UNKNOWN;
 407	b->disk_key.objectid = 0;
 408	b->disk_key.type = 0;
 409	b->disk_key.offset = 0;
 410	b->is_metadata = 0;
 411	b->is_superblock = 0;
 412	b->is_iodone = 0;
 413	b->iodone_w_error = 0;
 414	b->never_written = 0;
 415	b->mirror_num = 0;
 416	b->next_in_same_bio = NULL;
 417	b->orig_bio_bh_private = NULL;
 418	b->orig_bio_bh_end_io.bio = NULL;
 419	INIT_LIST_HEAD(&b->collision_resolving_node);
 420	INIT_LIST_HEAD(&b->all_blocks_node);
 421	INIT_LIST_HEAD(&b->ref_to_list);
 422	INIT_LIST_HEAD(&b->ref_from_list);
 423	b->submit_bio_bh_rw = 0;
 424	b->flush_gen = 0;
 425}
 426
 427static struct btrfsic_block *btrfsic_block_alloc(void)
 428{
 429	struct btrfsic_block *b;
 430
 431	b = kzalloc(sizeof(*b), GFP_NOFS);
 432	if (NULL != b)
 433		btrfsic_block_init(b);
 434
 435	return b;
 436}
 437
 438static void btrfsic_block_free(struct btrfsic_block *b)
 439{
 440	BUG_ON(!(NULL == b || BTRFSIC_BLOCK_MAGIC_NUMBER == b->magic_num));
 441	kfree(b);
 442}
 443
 444static void btrfsic_block_link_init(struct btrfsic_block_link *l)
 445{
 446	l->magic_num = BTRFSIC_BLOCK_LINK_MAGIC_NUMBER;
 447	l->ref_cnt = 1;
 448	INIT_LIST_HEAD(&l->node_ref_to);
 449	INIT_LIST_HEAD(&l->node_ref_from);
 450	INIT_LIST_HEAD(&l->collision_resolving_node);
 451	l->block_ref_to = NULL;
 452	l->block_ref_from = NULL;
 453}
 454
 455static struct btrfsic_block_link *btrfsic_block_link_alloc(void)
 456{
 457	struct btrfsic_block_link *l;
 458
 459	l = kzalloc(sizeof(*l), GFP_NOFS);
 460	if (NULL != l)
 461		btrfsic_block_link_init(l);
 462
 463	return l;
 464}
 465
 466static void btrfsic_block_link_free(struct btrfsic_block_link *l)
 467{
 468	BUG_ON(!(NULL == l || BTRFSIC_BLOCK_LINK_MAGIC_NUMBER == l->magic_num));
 469	kfree(l);
 470}
 471
 472static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds)
 473{
 474	ds->magic_num = BTRFSIC_DEV2STATE_MAGIC_NUMBER;
 475	ds->bdev = NULL;
 476	ds->state = NULL;
 477	ds->name[0] = '\0';
 478	INIT_LIST_HEAD(&ds->collision_resolving_node);
 479	ds->last_flush_gen = 0;
 480	btrfsic_block_init(&ds->dummy_block_for_bio_bh_flush);
 481	ds->dummy_block_for_bio_bh_flush.is_iodone = 1;
 482	ds->dummy_block_for_bio_bh_flush.dev_state = ds;
 483}
 484
 485static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void)
 486{
 487	struct btrfsic_dev_state *ds;
 488
 489	ds = kzalloc(sizeof(*ds), GFP_NOFS);
 490	if (NULL != ds)
 491		btrfsic_dev_state_init(ds);
 492
 493	return ds;
 494}
 495
 496static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds)
 497{
 498	BUG_ON(!(NULL == ds ||
 499		 BTRFSIC_DEV2STATE_MAGIC_NUMBER == ds->magic_num));
 500	kfree(ds);
 501}
 502
 503static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h)
 504{
 505	int i;
 506
 507	for (i = 0; i < BTRFSIC_BLOCK_HASHTABLE_SIZE; i++)
 508		INIT_LIST_HEAD(h->table + i);
 509}
 510
 511static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
 512					struct btrfsic_block_hashtable *h)
 513{
 514	const unsigned int hashval =
 515	    (((unsigned int)(b->dev_bytenr >> 16)) ^
 516	     ((unsigned int)((uintptr_t)b->dev_state->bdev))) &
 517	     (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
 518
 519	list_add(&b->collision_resolving_node, h->table + hashval);
 520}
 521
 522static void btrfsic_block_hashtable_remove(struct btrfsic_block *b)
 523{
 524	list_del(&b->collision_resolving_node);
 525}
 526
 527static struct btrfsic_block *btrfsic_block_hashtable_lookup(
 528		struct block_device *bdev,
 529		u64 dev_bytenr,
 530		struct btrfsic_block_hashtable *h)
 531{
 532	const unsigned int hashval =
 533	    (((unsigned int)(dev_bytenr >> 16)) ^
 534	     ((unsigned int)((uintptr_t)bdev))) &
 535	     (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
 536	struct list_head *elem;
 537
 538	list_for_each(elem, h->table + hashval) {
 539		struct btrfsic_block *const b =
 540		    list_entry(elem, struct btrfsic_block,
 541			       collision_resolving_node);
 542
 543		if (b->dev_state->bdev == bdev && b->dev_bytenr == dev_bytenr)
 544			return b;
 545	}
 546
 547	return NULL;
 548}
 549
 550static void btrfsic_block_link_hashtable_init(
 551		struct btrfsic_block_link_hashtable *h)
 552{
 553	int i;
 554
 555	for (i = 0; i < BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE; i++)
 556		INIT_LIST_HEAD(h->table + i);
 557}
 558
 559static void btrfsic_block_link_hashtable_add(
 560		struct btrfsic_block_link *l,
 561		struct btrfsic_block_link_hashtable *h)
 562{
 563	const unsigned int hashval =
 564	    (((unsigned int)(l->block_ref_to->dev_bytenr >> 16)) ^
 565	     ((unsigned int)(l->block_ref_from->dev_bytenr >> 16)) ^
 566	     ((unsigned int)((uintptr_t)l->block_ref_to->dev_state->bdev)) ^
 567	     ((unsigned int)((uintptr_t)l->block_ref_from->dev_state->bdev)))
 568	     & (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
 569
 570	BUG_ON(NULL == l->block_ref_to);
 571	BUG_ON(NULL == l->block_ref_from);
 572	list_add(&l->collision_resolving_node, h->table + hashval);
 573}
 574
 575static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l)
 576{
 577	list_del(&l->collision_resolving_node);
 578}
 579
 580static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
 581		struct block_device *bdev_ref_to,
 582		u64 dev_bytenr_ref_to,
 583		struct block_device *bdev_ref_from,
 584		u64 dev_bytenr_ref_from,
 585		struct btrfsic_block_link_hashtable *h)
 586{
 587	const unsigned int hashval =
 588	    (((unsigned int)(dev_bytenr_ref_to >> 16)) ^
 589	     ((unsigned int)(dev_bytenr_ref_from >> 16)) ^
 590	     ((unsigned int)((uintptr_t)bdev_ref_to)) ^
 591	     ((unsigned int)((uintptr_t)bdev_ref_from))) &
 592	     (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
 593	struct list_head *elem;
 594
 595	list_for_each(elem, h->table + hashval) {
 596		struct btrfsic_block_link *const l =
 597		    list_entry(elem, struct btrfsic_block_link,
 598			       collision_resolving_node);
 599
 600		BUG_ON(NULL == l->block_ref_to);
 601		BUG_ON(NULL == l->block_ref_from);
 602		if (l->block_ref_to->dev_state->bdev == bdev_ref_to &&
 603		    l->block_ref_to->dev_bytenr == dev_bytenr_ref_to &&
 604		    l->block_ref_from->dev_state->bdev == bdev_ref_from &&
 605		    l->block_ref_from->dev_bytenr == dev_bytenr_ref_from)
 606			return l;
 607	}
 608
 609	return NULL;
 610}
 611
 612static void btrfsic_dev_state_hashtable_init(
 613		struct btrfsic_dev_state_hashtable *h)
 614{
 615	int i;
 616
 617	for (i = 0; i < BTRFSIC_DEV2STATE_HASHTABLE_SIZE; i++)
 618		INIT_LIST_HEAD(h->table + i);
 619}
 620
 621static void btrfsic_dev_state_hashtable_add(
 622		struct btrfsic_dev_state *ds,
 623		struct btrfsic_dev_state_hashtable *h)
 624{
 625	const unsigned int hashval =
 626	    (((unsigned int)((uintptr_t)ds->bdev)) &
 627	     (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
 628
 629	list_add(&ds->collision_resolving_node, h->table + hashval);
 630}
 631
 632static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds)
 633{
 634	list_del(&ds->collision_resolving_node);
 635}
 636
 637static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
 638		struct block_device *bdev,
 639		struct btrfsic_dev_state_hashtable *h)
 640{
 641	const unsigned int hashval =
 642	    (((unsigned int)((uintptr_t)bdev)) &
 643	     (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
 644	struct list_head *elem;
 645
 646	list_for_each(elem, h->table + hashval) {
 647		struct btrfsic_dev_state *const ds =
 648		    list_entry(elem, struct btrfsic_dev_state,
 649			       collision_resolving_node);
 650
 651		if (ds->bdev == bdev)
 652			return ds;
 653	}
 654
 655	return NULL;
 656}
 657
 658static int btrfsic_process_superblock(struct btrfsic_state *state,
 659				      struct btrfs_fs_devices *fs_devices)
 660{
 661	int ret = 0;
 662	struct btrfs_super_block *selected_super;
 663	struct list_head *dev_head = &fs_devices->devices;
 664	struct btrfs_device *device;
 665	struct btrfsic_dev_state *selected_dev_state = NULL;
 666	int pass;
 667
 668	BUG_ON(NULL == state);
 669	selected_super = kzalloc(sizeof(*selected_super), GFP_NOFS);
 670	if (NULL == selected_super) {
 671		printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
 672		return -1;
 673	}
 674
 675	list_for_each_entry(device, dev_head, dev_list) {
 676		int i;
 677		struct btrfsic_dev_state *dev_state;
 678
 679		if (!device->bdev || !device->name)
 680			continue;
 681
 682		dev_state = btrfsic_dev_state_lookup(device->bdev);
 683		BUG_ON(NULL == dev_state);
 684		for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 685			ret = btrfsic_process_superblock_dev_mirror(
 686					state, dev_state, device, i,
 687					&selected_dev_state, selected_super);
 688			if (0 != ret && 0 == i) {
 689				kfree(selected_super);
 690				return ret;
 691			}
 692		}
 693	}
 694
 695	if (NULL == state->latest_superblock) {
 696		printk(KERN_INFO "btrfsic: no superblock found!\n");
 697		kfree(selected_super);
 698		return -1;
 699	}
 700
 701	state->csum_size = btrfs_super_csum_size(selected_super);
 702
 703	for (pass = 0; pass < 3; pass++) {
 704		int num_copies;
 705		int mirror_num;
 706		u64 next_bytenr;
 707
 708		switch (pass) {
 709		case 0:
 710			next_bytenr = btrfs_super_root(selected_super);
 711			if (state->print_mask &
 712			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 713				printk(KERN_INFO "root@%llu\n", next_bytenr);
 714			break;
 715		case 1:
 716			next_bytenr = btrfs_super_chunk_root(selected_super);
 717			if (state->print_mask &
 718			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 719				printk(KERN_INFO "chunk@%llu\n", next_bytenr);
 720			break;
 721		case 2:
 722			next_bytenr = btrfs_super_log_root(selected_super);
 723			if (0 == next_bytenr)
 724				continue;
 725			if (state->print_mask &
 726			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 727				printk(KERN_INFO "log@%llu\n", next_bytenr);
 728			break;
 729		}
 730
 731		num_copies =
 732		    btrfs_num_copies(state->root->fs_info,
 733				     next_bytenr, state->metablock_size);
 734		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 735			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
 736			       next_bytenr, num_copies);
 737
 738		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 739			struct btrfsic_block *next_block;
 740			struct btrfsic_block_data_ctx tmp_next_block_ctx;
 741			struct btrfsic_block_link *l;
 742
 743			ret = btrfsic_map_block(state, next_bytenr,
 744						state->metablock_size,
 745						&tmp_next_block_ctx,
 746						mirror_num);
 747			if (ret) {
 748				printk(KERN_INFO "btrfsic:"
 749				       " btrfsic_map_block(root @%llu,"
 750				       " mirror %d) failed!\n",
 751				       next_bytenr, mirror_num);
 752				kfree(selected_super);
 753				return -1;
 754			}
 755
 756			next_block = btrfsic_block_hashtable_lookup(
 757					tmp_next_block_ctx.dev->bdev,
 758					tmp_next_block_ctx.dev_bytenr,
 759					&state->block_hashtable);
 760			BUG_ON(NULL == next_block);
 761
 762			l = btrfsic_block_link_hashtable_lookup(
 763					tmp_next_block_ctx.dev->bdev,
 764					tmp_next_block_ctx.dev_bytenr,
 765					state->latest_superblock->dev_state->
 766					bdev,
 767					state->latest_superblock->dev_bytenr,
 768					&state->block_link_hashtable);
 769			BUG_ON(NULL == l);
 770
 771			ret = btrfsic_read_block(state, &tmp_next_block_ctx);
 772			if (ret < (int)PAGE_CACHE_SIZE) {
 773				printk(KERN_INFO
 774				       "btrfsic: read @logical %llu failed!\n",
 775				       tmp_next_block_ctx.start);
 776				btrfsic_release_block_ctx(&tmp_next_block_ctx);
 777				kfree(selected_super);
 778				return -1;
 779			}
 780
 781			ret = btrfsic_process_metablock(state,
 782							next_block,
 783							&tmp_next_block_ctx,
 784							BTRFS_MAX_LEVEL + 3, 1);
 785			btrfsic_release_block_ctx(&tmp_next_block_ctx);
 786		}
 787	}
 788
 789	kfree(selected_super);
 790	return ret;
 791}
 792
 793static int btrfsic_process_superblock_dev_mirror(
 794		struct btrfsic_state *state,
 795		struct btrfsic_dev_state *dev_state,
 796		struct btrfs_device *device,
 797		int superblock_mirror_num,
 798		struct btrfsic_dev_state **selected_dev_state,
 799		struct btrfs_super_block *selected_super)
 800{
 801	struct btrfs_super_block *super_tmp;
 802	u64 dev_bytenr;
 803	struct buffer_head *bh;
 804	struct btrfsic_block *superblock_tmp;
 805	int pass;
 806	struct block_device *const superblock_bdev = device->bdev;
 807
 808	/* super block bytenr is always the unmapped device bytenr */
 809	dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
 810	if (dev_bytenr + BTRFS_SUPER_INFO_SIZE > device->total_bytes)
 811		return -1;
 812	bh = __bread(superblock_bdev, dev_bytenr / 4096,
 813		     BTRFS_SUPER_INFO_SIZE);
 814	if (NULL == bh)
 815		return -1;
 816	super_tmp = (struct btrfs_super_block *)
 817	    (bh->b_data + (dev_bytenr & 4095));
 818
 819	if (btrfs_super_bytenr(super_tmp) != dev_bytenr ||
 820	    btrfs_super_magic(super_tmp) != BTRFS_MAGIC ||
 821	    memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE) ||
 822	    btrfs_super_nodesize(super_tmp) != state->metablock_size ||
 823	    btrfs_super_leafsize(super_tmp) != state->metablock_size ||
 824	    btrfs_super_sectorsize(super_tmp) != state->datablock_size) {
 825		brelse(bh);
 826		return 0;
 827	}
 828
 829	superblock_tmp =
 830	    btrfsic_block_hashtable_lookup(superblock_bdev,
 831					   dev_bytenr,
 832					   &state->block_hashtable);
 833	if (NULL == superblock_tmp) {
 834		superblock_tmp = btrfsic_block_alloc();
 835		if (NULL == superblock_tmp) {
 836			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
 837			brelse(bh);
 838			return -1;
 839		}
 840		/* for superblock, only the dev_bytenr makes sense */
 841		superblock_tmp->dev_bytenr = dev_bytenr;
 842		superblock_tmp->dev_state = dev_state;
 843		superblock_tmp->logical_bytenr = dev_bytenr;
 844		superblock_tmp->generation = btrfs_super_generation(super_tmp);
 845		superblock_tmp->is_metadata = 1;
 846		superblock_tmp->is_superblock = 1;
 847		superblock_tmp->is_iodone = 1;
 848		superblock_tmp->never_written = 0;
 849		superblock_tmp->mirror_num = 1 + superblock_mirror_num;
 850		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
 851			printk_in_rcu(KERN_INFO "New initial S-block (bdev %p, %s)"
 852				     " @%llu (%s/%llu/%d)\n",
 853				     superblock_bdev,
 854				     rcu_str_deref(device->name), dev_bytenr,
 855				     dev_state->name, dev_bytenr,
 856				     superblock_mirror_num);
 857		list_add(&superblock_tmp->all_blocks_node,
 858			 &state->all_blocks_list);
 859		btrfsic_block_hashtable_add(superblock_tmp,
 860					    &state->block_hashtable);
 861	}
 862
 863	/* select the one with the highest generation field */
 864	if (btrfs_super_generation(super_tmp) >
 865	    state->max_superblock_generation ||
 866	    0 == state->max_superblock_generation) {
 867		memcpy(selected_super, super_tmp, sizeof(*selected_super));
 868		*selected_dev_state = dev_state;
 869		state->max_superblock_generation =
 870		    btrfs_super_generation(super_tmp);
 871		state->latest_superblock = superblock_tmp;
 872	}
 873
 874	for (pass = 0; pass < 3; pass++) {
 875		u64 next_bytenr;
 876		int num_copies;
 877		int mirror_num;
 878		const char *additional_string = NULL;
 879		struct btrfs_disk_key tmp_disk_key;
 880
 881		tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
 882		tmp_disk_key.offset = 0;
 883		switch (pass) {
 884		case 0:
 885			btrfs_set_disk_key_objectid(&tmp_disk_key,
 886						    BTRFS_ROOT_TREE_OBJECTID);
 887			additional_string = "initial root ";
 888			next_bytenr = btrfs_super_root(super_tmp);
 889			break;
 890		case 1:
 891			btrfs_set_disk_key_objectid(&tmp_disk_key,
 892						    BTRFS_CHUNK_TREE_OBJECTID);
 893			additional_string = "initial chunk ";
 894			next_bytenr = btrfs_super_chunk_root(super_tmp);
 895			break;
 896		case 2:
 897			btrfs_set_disk_key_objectid(&tmp_disk_key,
 898						    BTRFS_TREE_LOG_OBJECTID);
 899			additional_string = "initial log ";
 900			next_bytenr = btrfs_super_log_root(super_tmp);
 901			if (0 == next_bytenr)
 902				continue;
 903			break;
 904		}
 905
 906		num_copies =
 907		    btrfs_num_copies(state->root->fs_info,
 908				     next_bytenr, state->metablock_size);
 909		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 910			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
 911			       next_bytenr, num_copies);
 912		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 913			struct btrfsic_block *next_block;
 914			struct btrfsic_block_data_ctx tmp_next_block_ctx;
 915			struct btrfsic_block_link *l;
 916
 917			if (btrfsic_map_block(state, next_bytenr,
 918					      state->metablock_size,
 919					      &tmp_next_block_ctx,
 920					      mirror_num)) {
 921				printk(KERN_INFO "btrfsic: btrfsic_map_block("
 922				       "bytenr @%llu, mirror %d) failed!\n",
 923				       next_bytenr, mirror_num);
 924				brelse(bh);
 925				return -1;
 926			}
 927
 928			next_block = btrfsic_block_lookup_or_add(
 929					state, &tmp_next_block_ctx,
 930					additional_string, 1, 1, 0,
 931					mirror_num, NULL);
 932			if (NULL == next_block) {
 933				btrfsic_release_block_ctx(&tmp_next_block_ctx);
 934				brelse(bh);
 935				return -1;
 936			}
 937
 938			next_block->disk_key = tmp_disk_key;
 939			next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
 940			l = btrfsic_block_link_lookup_or_add(
 941					state, &tmp_next_block_ctx,
 942					next_block, superblock_tmp,
 943					BTRFSIC_GENERATION_UNKNOWN);
 944			btrfsic_release_block_ctx(&tmp_next_block_ctx);
 945			if (NULL == l) {
 946				brelse(bh);
 947				return -1;
 948			}
 949		}
 950	}
 951	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES)
 952		btrfsic_dump_tree_sub(state, superblock_tmp, 0);
 953
 954	brelse(bh);
 955	return 0;
 956}
 957
 958static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void)
 959{
 960	struct btrfsic_stack_frame *sf;
 961
 962	sf = kzalloc(sizeof(*sf), GFP_NOFS);
 963	if (NULL == sf)
 964		printk(KERN_INFO "btrfsic: alloc memory failed!\n");
 965	else
 966		sf->magic = BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER;
 967	return sf;
 968}
 969
 970static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf)
 971{
 972	BUG_ON(!(NULL == sf ||
 973		 BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER == sf->magic));
 974	kfree(sf);
 975}
 976
 977static int btrfsic_process_metablock(
 978		struct btrfsic_state *state,
 979		struct btrfsic_block *const first_block,
 980		struct btrfsic_block_data_ctx *const first_block_ctx,
 981		int first_limit_nesting, int force_iodone_flag)
 982{
 983	struct btrfsic_stack_frame initial_stack_frame = { 0 };
 984	struct btrfsic_stack_frame *sf;
 985	struct btrfsic_stack_frame *next_stack;
 986	struct btrfs_header *const first_hdr =
 987		(struct btrfs_header *)first_block_ctx->datav[0];
 988
 989	BUG_ON(!first_hdr);
 990	sf = &initial_stack_frame;
 991	sf->error = 0;
 992	sf->i = -1;
 993	sf->limit_nesting = first_limit_nesting;
 994	sf->block = first_block;
 995	sf->block_ctx = first_block_ctx;
 996	sf->next_block = NULL;
 997	sf->hdr = first_hdr;
 998	sf->prev = NULL;
 999
1000continue_with_new_stack_frame:
1001	sf->block->generation = le64_to_cpu(sf->hdr->generation);
1002	if (0 == sf->hdr->level) {
1003		struct btrfs_leaf *const leafhdr =
1004		    (struct btrfs_leaf *)sf->hdr;
1005
1006		if (-1 == sf->i) {
1007			sf->nr = btrfs_stack_header_nritems(&leafhdr->header);
1008
1009			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1010				printk(KERN_INFO
1011				       "leaf %llu items %d generation %llu"
1012				       " owner %llu\n",
1013				       sf->block_ctx->start, sf->nr,
1014				       btrfs_stack_header_generation(
1015					       &leafhdr->header),
1016				       btrfs_stack_header_owner(
1017					       &leafhdr->header));
1018		}
1019
1020continue_with_current_leaf_stack_frame:
1021		if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1022			sf->i++;
1023			sf->num_copies = 0;
1024		}
1025
1026		if (sf->i < sf->nr) {
1027			struct btrfs_item disk_item;
1028			u32 disk_item_offset =
1029				(uintptr_t)(leafhdr->items + sf->i) -
1030				(uintptr_t)leafhdr;
1031			struct btrfs_disk_key *disk_key;
1032			u8 type;
1033			u32 item_offset;
1034			u32 item_size;
1035
1036			if (disk_item_offset + sizeof(struct btrfs_item) >
1037			    sf->block_ctx->len) {
1038leaf_item_out_of_bounce_error:
1039				printk(KERN_INFO
1040				       "btrfsic: leaf item out of bounce at logical %llu, dev %s\n",
1041				       sf->block_ctx->start,
1042				       sf->block_ctx->dev->name);
1043				goto one_stack_frame_backwards;
1044			}
1045			btrfsic_read_from_block_data(sf->block_ctx,
1046						     &disk_item,
1047						     disk_item_offset,
1048						     sizeof(struct btrfs_item));
1049			item_offset = btrfs_stack_item_offset(&disk_item);
1050			item_size = btrfs_stack_item_size(&disk_item);
1051			disk_key = &disk_item.key;
1052			type = btrfs_disk_key_type(disk_key);
1053
1054			if (BTRFS_ROOT_ITEM_KEY == type) {
1055				struct btrfs_root_item root_item;
1056				u32 root_item_offset;
1057				u64 next_bytenr;
1058
1059				root_item_offset = item_offset +
1060					offsetof(struct btrfs_leaf, items);
1061				if (root_item_offset + item_size >
1062				    sf->block_ctx->len)
1063					goto leaf_item_out_of_bounce_error;
1064				btrfsic_read_from_block_data(
1065					sf->block_ctx, &root_item,
1066					root_item_offset,
1067					item_size);
1068				next_bytenr = btrfs_root_bytenr(&root_item);
1069
1070				sf->error =
1071				    btrfsic_create_link_to_next_block(
1072						state,
1073						sf->block,
1074						sf->block_ctx,
1075						next_bytenr,
1076						sf->limit_nesting,
1077						&sf->next_block_ctx,
1078						&sf->next_block,
1079						force_iodone_flag,
1080						&sf->num_copies,
1081						&sf->mirror_num,
1082						disk_key,
1083						btrfs_root_generation(
1084						&root_item));
1085				if (sf->error)
1086					goto one_stack_frame_backwards;
1087
1088				if (NULL != sf->next_block) {
1089					struct btrfs_header *const next_hdr =
1090					    (struct btrfs_header *)
1091					    sf->next_block_ctx.datav[0];
1092
1093					next_stack =
1094					    btrfsic_stack_frame_alloc();
1095					if (NULL == next_stack) {
1096						btrfsic_release_block_ctx(
1097								&sf->
1098								next_block_ctx);
1099						goto one_stack_frame_backwards;
1100					}
1101
1102					next_stack->i = -1;
1103					next_stack->block = sf->next_block;
1104					next_stack->block_ctx =
1105					    &sf->next_block_ctx;
1106					next_stack->next_block = NULL;
1107					next_stack->hdr = next_hdr;
1108					next_stack->limit_nesting =
1109					    sf->limit_nesting - 1;
1110					next_stack->prev = sf;
1111					sf = next_stack;
1112					goto continue_with_new_stack_frame;
1113				}
1114			} else if (BTRFS_EXTENT_DATA_KEY == type &&
1115				   state->include_extent_data) {
1116				sf->error = btrfsic_handle_extent_data(
1117						state,
1118						sf->block,
1119						sf->block_ctx,
1120						item_offset,
1121						force_iodone_flag);
1122				if (sf->error)
1123					goto one_stack_frame_backwards;
1124			}
1125
1126			goto continue_with_current_leaf_stack_frame;
1127		}
1128	} else {
1129		struct btrfs_node *const nodehdr = (struct btrfs_node *)sf->hdr;
1130
1131		if (-1 == sf->i) {
1132			sf->nr = btrfs_stack_header_nritems(&nodehdr->header);
1133
1134			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1135				printk(KERN_INFO "node %llu level %d items %d"
1136				       " generation %llu owner %llu\n",
1137				       sf->block_ctx->start,
1138				       nodehdr->header.level, sf->nr,
1139				       btrfs_stack_header_generation(
1140				       &nodehdr->header),
1141				       btrfs_stack_header_owner(
1142				       &nodehdr->header));
1143		}
1144
1145continue_with_current_node_stack_frame:
1146		if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1147			sf->i++;
1148			sf->num_copies = 0;
1149		}
1150
1151		if (sf->i < sf->nr) {
1152			struct btrfs_key_ptr key_ptr;
1153			u32 key_ptr_offset;
1154			u64 next_bytenr;
1155
1156			key_ptr_offset = (uintptr_t)(nodehdr->ptrs + sf->i) -
1157					  (uintptr_t)nodehdr;
1158			if (key_ptr_offset + sizeof(struct btrfs_key_ptr) >
1159			    sf->block_ctx->len) {
1160				printk(KERN_INFO
1161				       "btrfsic: node item out of bounce at logical %llu, dev %s\n",
1162				       sf->block_ctx->start,
1163				       sf->block_ctx->dev->name);
1164				goto one_stack_frame_backwards;
1165			}
1166			btrfsic_read_from_block_data(
1167				sf->block_ctx, &key_ptr, key_ptr_offset,
1168				sizeof(struct btrfs_key_ptr));
1169			next_bytenr = btrfs_stack_key_blockptr(&key_ptr);
1170
1171			sf->error = btrfsic_create_link_to_next_block(
1172					state,
1173					sf->block,
1174					sf->block_ctx,
1175					next_bytenr,
1176					sf->limit_nesting,
1177					&sf->next_block_ctx,
1178					&sf->next_block,
1179					force_iodone_flag,
1180					&sf->num_copies,
1181					&sf->mirror_num,
1182					&key_ptr.key,
1183					btrfs_stack_key_generation(&key_ptr));
1184			if (sf->error)
1185				goto one_stack_frame_backwards;
1186
1187			if (NULL != sf->next_block) {
1188				struct btrfs_header *const next_hdr =
1189				    (struct btrfs_header *)
1190				    sf->next_block_ctx.datav[0];
1191
1192				next_stack = btrfsic_stack_frame_alloc();
1193				if (NULL == next_stack)
1194					goto one_stack_frame_backwards;
1195
1196				next_stack->i = -1;
1197				next_stack->block = sf->next_block;
1198				next_stack->block_ctx = &sf->next_block_ctx;
1199				next_stack->next_block = NULL;
1200				next_stack->hdr = next_hdr;
1201				next_stack->limit_nesting =
1202				    sf->limit_nesting - 1;
1203				next_stack->prev = sf;
1204				sf = next_stack;
1205				goto continue_with_new_stack_frame;
1206			}
1207
1208			goto continue_with_current_node_stack_frame;
1209		}
1210	}
1211
1212one_stack_frame_backwards:
1213	if (NULL != sf->prev) {
1214		struct btrfsic_stack_frame *const prev = sf->prev;
1215
1216		/* the one for the initial block is freed in the caller */
1217		btrfsic_release_block_ctx(sf->block_ctx);
1218
1219		if (sf->error) {
1220			prev->error = sf->error;
1221			btrfsic_stack_frame_free(sf);
1222			sf = prev;
1223			goto one_stack_frame_backwards;
1224		}
1225
1226		btrfsic_stack_frame_free(sf);
1227		sf = prev;
1228		goto continue_with_new_stack_frame;
1229	} else {
1230		BUG_ON(&initial_stack_frame != sf);
1231	}
1232
1233	return sf->error;
1234}
1235
1236static void btrfsic_read_from_block_data(
1237	struct btrfsic_block_data_ctx *block_ctx,
1238	void *dstv, u32 offset, size_t len)
1239{
1240	size_t cur;
1241	size_t offset_in_page;
1242	char *kaddr;
1243	char *dst = (char *)dstv;
1244	size_t start_offset = block_ctx->start & ((u64)PAGE_CACHE_SIZE - 1);
1245	unsigned long i = (start_offset + offset) >> PAGE_CACHE_SHIFT;
1246
1247	WARN_ON(offset + len > block_ctx->len);
1248	offset_in_page = (start_offset + offset) & (PAGE_CACHE_SIZE - 1);
1249
1250	while (len > 0) {
1251		cur = min(len, ((size_t)PAGE_CACHE_SIZE - offset_in_page));
1252		BUG_ON(i >= (block_ctx->len + PAGE_CACHE_SIZE - 1) >>
1253			    PAGE_CACHE_SHIFT);
1254		kaddr = block_ctx->datav[i];
1255		memcpy(dst, kaddr + offset_in_page, cur);
1256
1257		dst += cur;
1258		len -= cur;
1259		offset_in_page = 0;
1260		i++;
1261	}
1262}
1263
1264static int btrfsic_create_link_to_next_block(
1265		struct btrfsic_state *state,
1266		struct btrfsic_block *block,
1267		struct btrfsic_block_data_ctx *block_ctx,
1268		u64 next_bytenr,
1269		int limit_nesting,
1270		struct btrfsic_block_data_ctx *next_block_ctx,
1271		struct btrfsic_block **next_blockp,
1272		int force_iodone_flag,
1273		int *num_copiesp, int *mirror_nump,
1274		struct btrfs_disk_key *disk_key,
1275		u64 parent_generation)
1276{
1277	struct btrfsic_block *next_block = NULL;
1278	int ret;
1279	struct btrfsic_block_link *l;
1280	int did_alloc_block_link;
1281	int block_was_created;
1282
1283	*next_blockp = NULL;
1284	if (0 == *num_copiesp) {
1285		*num_copiesp =
1286		    btrfs_num_copies(state->root->fs_info,
1287				     next_bytenr, state->metablock_size);
1288		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1289			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1290			       next_bytenr, *num_copiesp);
1291		*mirror_nump = 1;
1292	}
1293
1294	if (*mirror_nump > *num_copiesp)
1295		return 0;
1296
1297	if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1298		printk(KERN_INFO
1299		       "btrfsic_create_link_to_next_block(mirror_num=%d)\n",
1300		       *mirror_nump);
1301	ret = btrfsic_map_block(state, next_bytenr,
1302				state->metablock_size,
1303				next_block_ctx, *mirror_nump);
1304	if (ret) {
1305		printk(KERN_INFO
1306		       "btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1307		       next_bytenr, *mirror_nump);
1308		btrfsic_release_block_ctx(next_block_ctx);
1309		*next_blockp = NULL;
1310		return -1;
1311	}
1312
1313	next_block = btrfsic_block_lookup_or_add(state,
1314						 next_block_ctx, "referenced ",
1315						 1, force_iodone_flag,
1316						 !force_iodone_flag,
1317						 *mirror_nump,
1318						 &block_was_created);
1319	if (NULL == next_block) {
1320		btrfsic_release_block_ctx(next_block_ctx);
1321		*next_blockp = NULL;
1322		return -1;
1323	}
1324	if (block_was_created) {
1325		l = NULL;
1326		next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
1327	} else {
1328		if (next_block->logical_bytenr != next_bytenr &&
1329		    !(!next_block->is_metadata &&
1330		      0 == next_block->logical_bytenr)) {
1331			printk(KERN_INFO
1332			       "Referenced block @%llu (%s/%llu/%d)"
1333			       " found in hash table, %c,"
1334			       " bytenr mismatch (!= stored %llu).\n",
1335			       next_bytenr, next_block_ctx->dev->name,
1336			       next_block_ctx->dev_bytenr, *mirror_nump,
1337			       btrfsic_get_block_type(state, next_block),
1338			       next_block->logical_bytenr);
1339		} else if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1340			printk(KERN_INFO
1341			       "Referenced block @%llu (%s/%llu/%d)"
1342			       " found in hash table, %c.\n",
1343			       next_bytenr, next_block_ctx->dev->name,
1344			       next_block_ctx->dev_bytenr, *mirror_nump,
1345			       btrfsic_get_block_type(state, next_block));
1346		next_block->logical_bytenr = next_bytenr;
1347
1348		next_block->mirror_num = *mirror_nump;
1349		l = btrfsic_block_link_hashtable_lookup(
1350				next_block_ctx->dev->bdev,
1351				next_block_ctx->dev_bytenr,
1352				block_ctx->dev->bdev,
1353				block_ctx->dev_bytenr,
1354				&state->block_link_hashtable);
1355	}
1356
1357	next_block->disk_key = *disk_key;
1358	if (NULL == l) {
1359		l = btrfsic_block_link_alloc();
1360		if (NULL == l) {
1361			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
1362			btrfsic_release_block_ctx(next_block_ctx);
1363			*next_blockp = NULL;
1364			return -1;
1365		}
1366
1367		did_alloc_block_link = 1;
1368		l->block_ref_to = next_block;
1369		l->block_ref_from = block;
1370		l->ref_cnt = 1;
1371		l->parent_generation = parent_generation;
1372
1373		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1374			btrfsic_print_add_link(state, l);
1375
1376		list_add(&l->node_ref_to, &block->ref_to_list);
1377		list_add(&l->node_ref_from, &next_block->ref_from_list);
1378
1379		btrfsic_block_link_hashtable_add(l,
1380						 &state->block_link_hashtable);
1381	} else {
1382		did_alloc_block_link = 0;
1383		if (0 == limit_nesting) {
1384			l->ref_cnt++;
1385			l->parent_generation = parent_generation;
1386			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1387				btrfsic_print_add_link(state, l);
1388		}
1389	}
1390
1391	if (limit_nesting > 0 && did_alloc_block_link) {
1392		ret = btrfsic_read_block(state, next_block_ctx);
1393		if (ret < (int)next_block_ctx->len) {
1394			printk(KERN_INFO
1395			       "btrfsic: read block @logical %llu failed!\n",
1396			       next_bytenr);
1397			btrfsic_release_block_ctx(next_block_ctx);
1398			*next_blockp = NULL;
1399			return -1;
1400		}
1401
1402		*next_blockp = next_block;
1403	} else {
1404		*next_blockp = NULL;
1405	}
1406	(*mirror_nump)++;
1407
1408	return 0;
1409}
1410
1411static int btrfsic_handle_extent_data(
1412		struct btrfsic_state *state,
1413		struct btrfsic_block *block,
1414		struct btrfsic_block_data_ctx *block_ctx,
1415		u32 item_offset, int force_iodone_flag)
1416{
1417	int ret;
1418	struct btrfs_file_extent_item file_extent_item;
1419	u64 file_extent_item_offset;
1420	u64 next_bytenr;
1421	u64 num_bytes;
1422	u64 generation;
1423	struct btrfsic_block_link *l;
1424
1425	file_extent_item_offset = offsetof(struct btrfs_leaf, items) +
1426				  item_offset;
1427	if (file_extent_item_offset +
1428	    offsetof(struct btrfs_file_extent_item, disk_num_bytes) >
1429	    block_ctx->len) {
1430		printk(KERN_INFO
1431		       "btrfsic: file item out of bounce at logical %llu, dev %s\n",
1432		       block_ctx->start, block_ctx->dev->name);
1433		return -1;
1434	}
1435
1436	btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1437		file_extent_item_offset,
1438		offsetof(struct btrfs_file_extent_item, disk_num_bytes));
1439	if (BTRFS_FILE_EXTENT_REG != file_extent_item.type ||
1440	    btrfs_stack_file_extent_disk_bytenr(&file_extent_item) == 0) {
1441		if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1442			printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu\n",
1443			       file_extent_item.type,
1444			       btrfs_stack_file_extent_disk_bytenr(
1445			       &file_extent_item));
1446		return 0;
1447	}
1448
1449	if (file_extent_item_offset + sizeof(struct btrfs_file_extent_item) >
1450	    block_ctx->len) {
1451		printk(KERN_INFO
1452		       "btrfsic: file item out of bounce at logical %llu, dev %s\n",
1453		       block_ctx->start, block_ctx->dev->name);
1454		return -1;
1455	}
1456	btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1457				     file_extent_item_offset,
1458				     sizeof(struct btrfs_file_extent_item));
1459	next_bytenr = btrfs_stack_file_extent_disk_bytenr(&file_extent_item);
1460	if (btrfs_stack_file_extent_compression(&file_extent_item) ==
1461	    BTRFS_COMPRESS_NONE) {
1462		next_bytenr += btrfs_stack_file_extent_offset(&file_extent_item);
1463		num_bytes = btrfs_stack_file_extent_num_bytes(&file_extent_item);
1464	} else {
1465		num_bytes = btrfs_stack_file_extent_disk_num_bytes(&file_extent_item);
1466	}
1467	generation = btrfs_stack_file_extent_generation(&file_extent_item);
1468
1469	if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1470		printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu,"
1471		       " offset = %llu, num_bytes = %llu\n",
1472		       file_extent_item.type,
1473		       btrfs_stack_file_extent_disk_bytenr(&file_extent_item),
1474		       btrfs_stack_file_extent_offset(&file_extent_item),
1475		       num_bytes);
1476	while (num_bytes > 0) {
1477		u32 chunk_len;
1478		int num_copies;
1479		int mirror_num;
1480
1481		if (num_bytes > state->datablock_size)
1482			chunk_len = state->datablock_size;
1483		else
1484			chunk_len = num_bytes;
1485
1486		num_copies =
1487		    btrfs_num_copies(state->root->fs_info,
1488				     next_bytenr, state->datablock_size);
1489		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1490			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1491			       next_bytenr, num_copies);
1492		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
1493			struct btrfsic_block_data_ctx next_block_ctx;
1494			struct btrfsic_block *next_block;
1495			int block_was_created;
1496
1497			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1498				printk(KERN_INFO "btrfsic_handle_extent_data("
1499				       "mirror_num=%d)\n", mirror_num);
1500			if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1501				printk(KERN_INFO
1502				       "\tdisk_bytenr = %llu, num_bytes %u\n",
1503				       next_bytenr, chunk_len);
1504			ret = btrfsic_map_block(state, next_bytenr,
1505						chunk_len, &next_block_ctx,
1506						mirror_num);
1507			if (ret) {
1508				printk(KERN_INFO
1509				       "btrfsic: btrfsic_map_block(@%llu,"
1510				       " mirror=%d) failed!\n",
1511				       next_bytenr, mirror_num);
1512				return -1;
1513			}
1514
1515			next_block = btrfsic_block_lookup_or_add(
1516					state,
1517					&next_block_ctx,
1518					"referenced ",
1519					0,
1520					force_iodone_flag,
1521					!force_iodone_flag,
1522					mirror_num,
1523					&block_was_created);
1524			if (NULL == next_block) {
1525				printk(KERN_INFO
1526				       "btrfsic: error, kmalloc failed!\n");
1527				btrfsic_release_block_ctx(&next_block_ctx);
1528				return -1;
1529			}
1530			if (!block_was_created) {
1531				if (next_block->logical_bytenr != next_bytenr &&
1532				    !(!next_block->is_metadata &&
1533				      0 == next_block->logical_bytenr)) {
1534					printk(KERN_INFO
1535					       "Referenced block"
1536					       " @%llu (%s/%llu/%d)"
1537					       " found in hash table, D,"
1538					       " bytenr mismatch"
1539					       " (!= stored %llu).\n",
1540					       next_bytenr,
1541					       next_block_ctx.dev->name,
1542					       next_block_ctx.dev_bytenr,
1543					       mirror_num,
1544					       next_block->logical_bytenr);
1545				}
1546				next_block->logical_bytenr = next_bytenr;
1547				next_block->mirror_num = mirror_num;
1548			}
1549
1550			l = btrfsic_block_link_lookup_or_add(state,
1551							     &next_block_ctx,
1552							     next_block, block,
1553							     generation);
1554			btrfsic_release_block_ctx(&next_block_ctx);
1555			if (NULL == l)
1556				return -1;
1557		}
1558
1559		next_bytenr += chunk_len;
1560		num_bytes -= chunk_len;
1561	}
1562
1563	return 0;
1564}
1565
1566static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
1567			     struct btrfsic_block_data_ctx *block_ctx_out,
1568			     int mirror_num)
1569{
1570	int ret;
1571	u64 length;
1572	struct btrfs_bio *multi = NULL;
1573	struct btrfs_device *device;
1574
1575	length = len;
1576	ret = btrfs_map_block(state->root->fs_info, READ,
1577			      bytenr, &length, &multi, mirror_num);
1578
1579	if (ret) {
1580		block_ctx_out->start = 0;
1581		block_ctx_out->dev_bytenr = 0;
1582		block_ctx_out->len = 0;
1583		block_ctx_out->dev = NULL;
1584		block_ctx_out->datav = NULL;
1585		block_ctx_out->pagev = NULL;
1586		block_ctx_out->mem_to_free = NULL;
1587
1588		return ret;
1589	}
1590
1591	device = multi->stripes[0].dev;
1592	block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev);
1593	block_ctx_out->dev_bytenr = multi->stripes[0].physical;
1594	block_ctx_out->start = bytenr;
1595	block_ctx_out->len = len;
1596	block_ctx_out->datav = NULL;
1597	block_ctx_out->pagev = NULL;
1598	block_ctx_out->mem_to_free = NULL;
1599
1600	kfree(multi);
1601	if (NULL == block_ctx_out->dev) {
1602		ret = -ENXIO;
1603		printk(KERN_INFO "btrfsic: error, cannot lookup dev (#1)!\n");
1604	}
1605
1606	return ret;
1607}
1608
1609static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
1610				  u32 len, struct block_device *bdev,
1611				  struct btrfsic_block_data_ctx *block_ctx_out)
1612{
1613	block_ctx_out->dev = btrfsic_dev_state_lookup(bdev);
1614	block_ctx_out->dev_bytenr = bytenr;
1615	block_ctx_out->start = bytenr;
1616	block_ctx_out->len = len;
1617	block_ctx_out->datav = NULL;
1618	block_ctx_out->pagev = NULL;
1619	block_ctx_out->mem_to_free = NULL;
1620	if (NULL != block_ctx_out->dev) {
1621		return 0;
1622	} else {
1623		printk(KERN_INFO "btrfsic: error, cannot lookup dev (#2)!\n");
1624		return -ENXIO;
1625	}
1626}
1627
1628static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
1629{
1630	if (block_ctx->mem_to_free) {
1631		unsigned int num_pages;
1632
1633		BUG_ON(!block_ctx->datav);
1634		BUG_ON(!block_ctx->pagev);
1635		num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
1636			    PAGE_CACHE_SHIFT;
1637		while (num_pages > 0) {
1638			num_pages--;
1639			if (block_ctx->datav[num_pages]) {
1640				kunmap(block_ctx->pagev[num_pages]);
1641				block_ctx->datav[num_pages] = NULL;
1642			}
1643			if (block_ctx->pagev[num_pages]) {
1644				__free_page(block_ctx->pagev[num_pages]);
1645				block_ctx->pagev[num_pages] = NULL;
1646			}
1647		}
1648
1649		kfree(block_ctx->mem_to_free);
1650		block_ctx->mem_to_free = NULL;
1651		block_ctx->pagev = NULL;
1652		block_ctx->datav = NULL;
1653	}
1654}
1655
1656static int btrfsic_read_block(struct btrfsic_state *state,
1657			      struct btrfsic_block_data_ctx *block_ctx)
1658{
1659	unsigned int num_pages;
1660	unsigned int i;
1661	u64 dev_bytenr;
1662	int ret;
1663
1664	BUG_ON(block_ctx->datav);
1665	BUG_ON(block_ctx->pagev);
1666	BUG_ON(block_ctx->mem_to_free);
1667	if (block_ctx->dev_bytenr & ((u64)PAGE_CACHE_SIZE - 1)) {
1668		printk(KERN_INFO
1669		       "btrfsic: read_block() with unaligned bytenr %llu\n",
1670		       block_ctx->dev_bytenr);
1671		return -1;
1672	}
1673
1674	num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
1675		    PAGE_CACHE_SHIFT;
1676	block_ctx->mem_to_free = kzalloc((sizeof(*block_ctx->datav) +
1677					  sizeof(*block_ctx->pagev)) *
1678					 num_pages, GFP_NOFS);
1679	if (!block_ctx->mem_to_free)
1680		return -1;
1681	block_ctx->datav = block_ctx->mem_to_free;
1682	block_ctx->pagev = (struct page **)(block_ctx->datav + num_pages);
1683	for (i = 0; i < num_pages; i++) {
1684		block_ctx->pagev[i] = alloc_page(GFP_NOFS);
1685		if (!block_ctx->pagev[i])
1686			return -1;
1687	}
1688
1689	dev_bytenr = block_ctx->dev_bytenr;
1690	for (i = 0; i < num_pages;) {
1691		struct bio *bio;
1692		unsigned int j;
1693
1694		bio = btrfs_io_bio_alloc(GFP_NOFS, num_pages - i);
1695		if (!bio) {
1696			printk(KERN_INFO
1697			       "btrfsic: bio_alloc() for %u pages failed!\n",
1698			       num_pages - i);
1699			return -1;
1700		}
1701		bio->bi_bdev = block_ctx->dev->bdev;
1702		bio->bi_iter.bi_sector = dev_bytenr >> 9;
1703
1704		for (j = i; j < num_pages; j++) {
1705			ret = bio_add_page(bio, block_ctx->pagev[j],
1706					   PAGE_CACHE_SIZE, 0);
1707			if (PAGE_CACHE_SIZE != ret)
1708				break;
1709		}
1710		if (j == i) {
1711			printk(KERN_INFO
1712			       "btrfsic: error, failed to add a single page!\n");
1713			return -1;
1714		}
1715		if (submit_bio_wait(READ, bio)) {
1716			printk(KERN_INFO
1717			       "btrfsic: read error at logical %llu dev %s!\n",
1718			       block_ctx->start, block_ctx->dev->name);
1719			bio_put(bio);
1720			return -1;
1721		}
1722		bio_put(bio);
1723		dev_bytenr += (j - i) * PAGE_CACHE_SIZE;
1724		i = j;
1725	}
1726	for (i = 0; i < num_pages; i++) {
1727		block_ctx->datav[i] = kmap(block_ctx->pagev[i]);
1728		if (!block_ctx->datav[i]) {
1729			printk(KERN_INFO "btrfsic: kmap() failed (dev %s)!\n",
1730			       block_ctx->dev->name);
1731			return -1;
1732		}
1733	}
1734
1735	return block_ctx->len;
1736}
1737
1738static void btrfsic_dump_database(struct btrfsic_state *state)
1739{
1740	struct list_head *elem_all;
1741
1742	BUG_ON(NULL == state);
1743
1744	printk(KERN_INFO "all_blocks_list:\n");
1745	list_for_each(elem_all, &state->all_blocks_list) {
1746		const struct btrfsic_block *const b_all =
1747		    list_entry(elem_all, struct btrfsic_block,
1748			       all_blocks_node);
1749		struct list_head *elem_ref_to;
1750		struct list_head *elem_ref_from;
1751
1752		printk(KERN_INFO "%c-block @%llu (%s/%llu/%d)\n",
1753		       btrfsic_get_block_type(state, b_all),
1754		       b_all->logical_bytenr, b_all->dev_state->name,
1755		       b_all->dev_bytenr, b_all->mirror_num);
1756
1757		list_for_each(elem_ref_to, &b_all->ref_to_list) {
1758			const struct btrfsic_block_link *const l =
1759			    list_entry(elem_ref_to,
1760				       struct btrfsic_block_link,
1761				       node_ref_to);
1762
1763			printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1764			       " refers %u* to"
1765			       " %c @%llu (%s/%llu/%d)\n",
1766			       btrfsic_get_block_type(state, b_all),
1767			       b_all->logical_bytenr, b_all->dev_state->name,
1768			       b_all->dev_bytenr, b_all->mirror_num,
1769			       l->ref_cnt,
1770			       btrfsic_get_block_type(state, l->block_ref_to),
1771			       l->block_ref_to->logical_bytenr,
1772			       l->block_ref_to->dev_state->name,
1773			       l->block_ref_to->dev_bytenr,
1774			       l->block_ref_to->mirror_num);
1775		}
1776
1777		list_for_each(elem_ref_from, &b_all->ref_from_list) {
1778			const struct btrfsic_block_link *const l =
1779			    list_entry(elem_ref_from,
1780				       struct btrfsic_block_link,
1781				       node_ref_from);
1782
1783			printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1784			       " is ref %u* from"
1785			       " %c @%llu (%s/%llu/%d)\n",
1786			       btrfsic_get_block_type(state, b_all),
1787			       b_all->logical_bytenr, b_all->dev_state->name,
1788			       b_all->dev_bytenr, b_all->mirror_num,
1789			       l->ref_cnt,
1790			       btrfsic_get_block_type(state, l->block_ref_from),
1791			       l->block_ref_from->logical_bytenr,
1792			       l->block_ref_from->dev_state->name,
1793			       l->block_ref_from->dev_bytenr,
1794			       l->block_ref_from->mirror_num);
1795		}
1796
1797		printk(KERN_INFO "\n");
1798	}
1799}
1800
1801/*
1802 * Test whether the disk block contains a tree block (leaf or node)
1803 * (note that this test fails for the super block)
1804 */
1805static int btrfsic_test_for_metadata(struct btrfsic_state *state,
1806				     char **datav, unsigned int num_pages)
1807{
1808	struct btrfs_header *h;
1809	u8 csum[BTRFS_CSUM_SIZE];
1810	u32 crc = ~(u32)0;
1811	unsigned int i;
1812
1813	if (num_pages * PAGE_CACHE_SIZE < state->metablock_size)
1814		return 1; /* not metadata */
1815	num_pages = state->metablock_size >> PAGE_CACHE_SHIFT;
1816	h = (struct btrfs_header *)datav[0];
1817
1818	if (memcmp(h->fsid, state->root->fs_info->fsid, BTRFS_UUID_SIZE))
1819		return 1;
1820
1821	for (i = 0; i < num_pages; i++) {
1822		u8 *data = i ? datav[i] : (datav[i] + BTRFS_CSUM_SIZE);
1823		size_t sublen = i ? PAGE_CACHE_SIZE :
1824				    (PAGE_CACHE_SIZE - BTRFS_CSUM_SIZE);
1825
1826		crc = btrfs_crc32c(crc, data, sublen);
1827	}
1828	btrfs_csum_final(crc, csum);
1829	if (memcmp(csum, h->csum, state->csum_size))
1830		return 1;
1831
1832	return 0; /* is metadata */
1833}
1834
1835static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
1836					  u64 dev_bytenr, char **mapped_datav,
1837					  unsigned int num_pages,
1838					  struct bio *bio, int *bio_is_patched,
1839					  struct buffer_head *bh,
1840					  int submit_bio_bh_rw)
1841{
1842	int is_metadata;
1843	struct btrfsic_block *block;
1844	struct btrfsic_block_data_ctx block_ctx;
1845	int ret;
1846	struct btrfsic_state *state = dev_state->state;
1847	struct block_device *bdev = dev_state->bdev;
1848	unsigned int processed_len;
1849
1850	if (NULL != bio_is_patched)
1851		*bio_is_patched = 0;
1852
1853again:
1854	if (num_pages == 0)
1855		return;
1856
1857	processed_len = 0;
1858	is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_datav,
1859						      num_pages));
1860
1861	block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
1862					       &state->block_hashtable);
1863	if (NULL != block) {
1864		u64 bytenr = 0;
1865		struct list_head *elem_ref_to;
1866		struct list_head *tmp_ref_to;
1867
1868		if (block->is_superblock) {
1869			bytenr = btrfs_super_bytenr((struct btrfs_super_block *)
1870						    mapped_datav[0]);
1871			if (num_pages * PAGE_CACHE_SIZE <
1872			    BTRFS_SUPER_INFO_SIZE) {
1873				printk(KERN_INFO
1874				       "btrfsic: cannot work with too short bios!\n");
1875				return;
1876			}
1877			is_metadata = 1;
1878			BUG_ON(BTRFS_SUPER_INFO_SIZE & (PAGE_CACHE_SIZE - 1));
1879			processed_len = BTRFS_SUPER_INFO_SIZE;
1880			if (state->print_mask &
1881			    BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
1882				printk(KERN_INFO
1883				       "[before new superblock is written]:\n");
1884				btrfsic_dump_tree_sub(state, block, 0);
1885			}
1886		}
1887		if (is_metadata) {
1888			if (!block->is_superblock) {
1889				if (num_pages * PAGE_CACHE_SIZE <
1890				    state->metablock_size) {
1891					printk(KERN_INFO
1892					       "btrfsic: cannot work with too short bios!\n");
1893					return;
1894				}
1895				processed_len = state->metablock_size;
1896				bytenr = btrfs_stack_header_bytenr(
1897						(struct btrfs_header *)
1898						mapped_datav[0]);
1899				btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
1900							       dev_state,
1901							       dev_bytenr);
1902			}
1903			if (block->logical_bytenr != bytenr &&
1904			    !(!block->is_metadata &&
1905			      block->logical_bytenr == 0))
1906				printk(KERN_INFO
1907				       "Written block @%llu (%s/%llu/%d)"
1908				       " found in hash table, %c,"
1909				       " bytenr mismatch"
1910				       " (!= stored %llu).\n",
1911				       bytenr, dev_state->name, dev_bytenr,
1912				       block->mirror_num,
1913				       btrfsic_get_block_type(state, block),
1914				       block->logical_bytenr);
1915			else if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1916				printk(KERN_INFO
1917				       "Written block @%llu (%s/%llu/%d)"
1918				       " found in hash table, %c.\n",
1919				       bytenr, dev_state->name, dev_bytenr,
1920				       block->mirror_num,
1921				       btrfsic_get_block_type(state, block));
1922			block->logical_bytenr = bytenr;
1923		} else {
1924			if (num_pages * PAGE_CACHE_SIZE <
1925			    state->datablock_size) {
1926				printk(KERN_INFO
1927				       "btrfsic: cannot work with too short bios!\n");
1928				return;
1929			}
1930			processed_len = state->datablock_size;
1931			bytenr = block->logical_bytenr;
1932			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1933				printk(KERN_INFO
1934				       "Written block @%llu (%s/%llu/%d)"
1935				       " found in hash table, %c.\n",
1936				       bytenr, dev_state->name, dev_bytenr,
1937				       block->mirror_num,
1938				       btrfsic_get_block_type(state, block));
1939		}
1940
1941		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1942			printk(KERN_INFO
1943			       "ref_to_list: %cE, ref_from_list: %cE\n",
1944			       list_empty(&block->ref_to_list) ? ' ' : '!',
1945			       list_empty(&block->ref_from_list) ? ' ' : '!');
1946		if (btrfsic_is_block_ref_by_superblock(state, block, 0)) {
1947			printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
1948			       " @%llu (%s/%llu/%d), old(gen=%llu,"
1949			       " objectid=%llu, type=%d, offset=%llu),"
1950			       " new(gen=%llu),"
1951			       " which is referenced by most recent superblock"
1952			       " (superblockgen=%llu)!\n",
1953			       btrfsic_get_block_type(state, block), bytenr,
1954			       dev_state->name, dev_bytenr, block->mirror_num,
1955			       block->generation,
1956			       btrfs_disk_key_objectid(&block->disk_key),
1957			       block->disk_key.type,
1958			       btrfs_disk_key_offset(&block->disk_key),
1959			       btrfs_stack_header_generation(
1960				       (struct btrfs_header *) mapped_datav[0]),
1961			       state->max_superblock_generation);
1962			btrfsic_dump_tree(state);
1963		}
1964
1965		if (!block->is_iodone && !block->never_written) {
1966			printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
1967			       " @%llu (%s/%llu/%d), oldgen=%llu, newgen=%llu,"
1968			       " which is not yet iodone!\n",
1969			       btrfsic_get_block_type(state, block), bytenr,
1970			       dev_state->name, dev_bytenr, block->mirror_num,
1971			       block->generation,
1972			       btrfs_stack_header_generation(
1973				       (struct btrfs_header *)
1974				       mapped_datav[0]));
1975			/* it would not be safe to go on */
1976			btrfsic_dump_tree(state);
1977			goto continue_loop;
1978		}
1979
1980		/*
1981		 * Clear all references of this block. Do not free
1982		 * the block itself even if is not referenced anymore
1983		 * because it still carries valueable information
1984		 * like whether it was ever written and IO completed.
1985		 */
1986		list_for_each_safe(elem_ref_to, tmp_ref_to,
1987				   &block->ref_to_list) {
1988			struct btrfsic_block_link *const l =
1989			    list_entry(elem_ref_to,
1990				       struct btrfsic_block_link,
1991				       node_ref_to);
1992
1993			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1994				btrfsic_print_rem_link(state, l);
1995			l->ref_cnt--;
1996			if (0 == l->ref_cnt) {
1997				list_del(&l->node_ref_to);
1998				list_del(&l->node_ref_from);
1999				btrfsic_block_link_hashtable_remove(l);
2000				btrfsic_block_link_free(l);
2001			}
2002		}
2003
2004		if (block->is_superblock)
2005			ret = btrfsic_map_superblock(state, bytenr,
2006						     processed_len,
2007						     bdev, &block_ctx);
2008		else
2009			ret = btrfsic_map_block(state, bytenr, processed_len,
2010						&block_ctx, 0);
2011		if (ret) {
2012			printk(KERN_INFO
2013			       "btrfsic: btrfsic_map_block(root @%llu)"
2014			       " failed!\n", bytenr);
2015			goto continue_loop;
2016		}
2017		block_ctx.datav = mapped_datav;
2018		/* the following is required in case of writes to mirrors,
2019		 * use the same that was used for the lookup */
2020		block_ctx.dev = dev_state;
2021		block_ctx.dev_bytenr = dev_bytenr;
2022
2023		if (is_metadata || state->include_extent_data) {
2024			block->never_written = 0;
2025			block->iodone_w_error = 0;
2026			if (NULL != bio) {
2027				block->is_iodone = 0;
2028				BUG_ON(NULL == bio_is_patched);
2029				if (!*bio_is_patched) {
2030					block->orig_bio_bh_private =
2031					    bio->bi_private;
2032					block->orig_bio_bh_end_io.bio =
2033					    bio->bi_end_io;
2034					block->next_in_same_bio = NULL;
2035					bio->bi_private = block;
2036					bio->bi_end_io = btrfsic_bio_end_io;
2037					*bio_is_patched = 1;
2038				} else {
2039					struct btrfsic_block *chained_block =
2040					    (struct btrfsic_block *)
2041					    bio->bi_private;
2042
2043					BUG_ON(NULL == chained_block);
2044					block->orig_bio_bh_private =
2045					    chained_block->orig_bio_bh_private;
2046					block->orig_bio_bh_end_io.bio =
2047					    chained_block->orig_bio_bh_end_io.
2048					    bio;
2049					block->next_in_same_bio = chained_block;
2050					bio->bi_private = block;
2051				}
2052			} else if (NULL != bh) {
2053				block->is_iodone = 0;
2054				block->orig_bio_bh_private = bh->b_private;
2055				block->orig_bio_bh_end_io.bh = bh->b_end_io;
2056				block->next_in_same_bio = NULL;
2057				bh->b_private = block;
2058				bh->b_end_io = btrfsic_bh_end_io;
2059			} else {
2060				block->is_iodone = 1;
2061				block->orig_bio_bh_private = NULL;
2062				block->orig_bio_bh_end_io.bio = NULL;
2063				block->next_in_same_bio = NULL;
2064			}
2065		}
2066
2067		block->flush_gen = dev_state->last_flush_gen + 1;
2068		block->submit_bio_bh_rw = submit_bio_bh_rw;
2069		if (is_metadata) {
2070			block->logical_bytenr = bytenr;
2071			block->is_metadata = 1;
2072			if (block->is_superblock) {
2073				BUG_ON(PAGE_CACHE_SIZE !=
2074				       BTRFS_SUPER_INFO_SIZE);
2075				ret = btrfsic_process_written_superblock(
2076						state,
2077						block,
2078						(struct btrfs_super_block *)
2079						mapped_datav[0]);
2080				if (state->print_mask &
2081				    BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE) {
2082					printk(KERN_INFO
2083					"[after new superblock is written]:\n");
2084					btrfsic_dump_tree_sub(state, block, 0);
2085				}
2086			} else {
2087				block->mirror_num = 0;	/* unknown */
2088				ret = btrfsic_process_metablock(
2089						state,
2090						block,
2091						&block_ctx,
2092						0, 0);
2093			}
2094			if (ret)
2095				printk(KERN_INFO
2096				       "btrfsic: btrfsic_process_metablock"
2097				       "(root @%llu) failed!\n",
2098				       dev_bytenr);
2099		} else {
2100			block->is_metadata = 0;
2101			block->mirror_num = 0;	/* unknown */
2102			block->generation = BTRFSIC_GENERATION_UNKNOWN;
2103			if (!state->include_extent_data
2104			    && list_empty(&block->ref_from_list)) {
2105				/*
2106				 * disk block is overwritten with extent
2107				 * data (not meta data) and we are configured
2108				 * to not include extent data: take the
2109				 * chance and free the block's memory
2110				 */
2111				btrfsic_block_hashtable_remove(block);
2112				list_del(&block->all_blocks_node);
2113				btrfsic_block_free(block);
2114			}
2115		}
2116		btrfsic_release_block_ctx(&block_ctx);
2117	} else {
2118		/* block has not been found in hash table */
2119		u64 bytenr;
2120
2121		if (!is_metadata) {
2122			processed_len = state->datablock_size;
2123			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2124				printk(KERN_INFO "Written block (%s/%llu/?)"
2125				       " !found in hash table, D.\n",
2126				       dev_state->name, dev_bytenr);
2127			if (!state->include_extent_data) {
2128				/* ignore that written D block */
2129				goto continue_loop;
2130			}
2131
2132			/* this is getting ugly for the
2133			 * include_extent_data case... */
2134			bytenr = 0;	/* unknown */
2135			block_ctx.start = bytenr;
2136			block_ctx.len = processed_len;
2137			block_ctx.mem_to_free = NULL;
2138			block_ctx.pagev = NULL;
2139		} else {
2140			processed_len = state->metablock_size;
2141			bytenr = btrfs_stack_header_bytenr(
2142					(struct btrfs_header *)
2143					mapped_datav[0]);
2144			btrfsic_cmp_log_and_dev_bytenr(state, bytenr, dev_state,
2145						       dev_bytenr);
2146			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2147				printk(KERN_INFO
2148				       "Written block @%llu (%s/%llu/?)"
2149				       " !found in hash table, M.\n",
2150				       bytenr, dev_state->name, dev_bytenr);
2151
2152			ret = btrfsic_map_block(state, bytenr, processed_len,
2153						&block_ctx, 0);
2154			if (ret) {
2155				printk(KERN_INFO
2156				       "btrfsic: btrfsic_map_block(root @%llu)"
2157				       " failed!\n",
2158				       dev_bytenr);
2159				goto continue_loop;
2160			}
2161		}
2162		block_ctx.datav = mapped_datav;
2163		/* the following is required in case of writes to mirrors,
2164		 * use the same that was used for the lookup */
2165		block_ctx.dev = dev_state;
2166		block_ctx.dev_bytenr = dev_bytenr;
2167
2168		block = btrfsic_block_alloc();
2169		if (NULL == block) {
2170			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2171			btrfsic_release_block_ctx(&block_ctx);
2172			goto continue_loop;
2173		}
2174		block->dev_state = dev_state;
2175		block->dev_bytenr = dev_bytenr;
2176		block->logical_bytenr = bytenr;
2177		block->is_metadata = is_metadata;
2178		block->never_written = 0;
2179		block->iodone_w_error = 0;
2180		block->mirror_num = 0;	/* unknown */
2181		block->flush_gen = dev_state->last_flush_gen + 1;
2182		block->submit_bio_bh_rw = submit_bio_bh_rw;
2183		if (NULL != bio) {
2184			block->is_iodone = 0;
2185			BUG_ON(NULL == bio_is_patched);
2186			if (!*bio_is_patched) {
2187				block->orig_bio_bh_private = bio->bi_private;
2188				block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2189				block->next_in_same_bio = NULL;
2190				bio->bi_private = block;
2191				bio->bi_end_io = btrfsic_bio_end_io;
2192				*bio_is_patched = 1;
2193			} else {
2194				struct btrfsic_block *chained_block =
2195				    (struct btrfsic_block *)
2196				    bio->bi_private;
2197
2198				BUG_ON(NULL == chained_block);
2199				block->orig_bio_bh_private =
2200				    chained_block->orig_bio_bh_private;
2201				block->orig_bio_bh_end_io.bio =
2202				    chained_block->orig_bio_bh_end_io.bio;
2203				block->next_in_same_bio = chained_block;
2204				bio->bi_private = block;
2205			}
2206		} else if (NULL != bh) {
2207			block->is_iodone = 0;
2208			block->orig_bio_bh_private = bh->b_private;
2209			block->orig_bio_bh_end_io.bh = bh->b_end_io;
2210			block->next_in_same_bio = NULL;
2211			bh->b_private = block;
2212			bh->b_end_io = btrfsic_bh_end_io;
2213		} else {
2214			block->is_iodone = 1;
2215			block->orig_bio_bh_private = NULL;
2216			block->orig_bio_bh_end_io.bio = NULL;
2217			block->next_in_same_bio = NULL;
2218		}
2219		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2220			printk(KERN_INFO
2221			       "New written %c-block @%llu (%s/%llu/%d)\n",
2222			       is_metadata ? 'M' : 'D',
2223			       block->logical_bytenr, block->dev_state->name,
2224			       block->dev_bytenr, block->mirror_num);
2225		list_add(&block->all_blocks_node, &state->all_blocks_list);
2226		btrfsic_block_hashtable_add(block, &state->block_hashtable);
2227
2228		if (is_metadata) {
2229			ret = btrfsic_process_metablock(state, block,
2230							&block_ctx, 0, 0);
2231			if (ret)
2232				printk(KERN_INFO
2233				       "btrfsic: process_metablock(root @%llu)"
2234				       " failed!\n",
2235				       dev_bytenr);
2236		}
2237		btrfsic_release_block_ctx(&block_ctx);
2238	}
2239
2240continue_loop:
2241	BUG_ON(!processed_len);
2242	dev_bytenr += processed_len;
2243	mapped_datav += processed_len >> PAGE_CACHE_SHIFT;
2244	num_pages -= processed_len >> PAGE_CACHE_SHIFT;
2245	goto again;
2246}
2247
2248static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status)
2249{
2250	struct btrfsic_block *block = (struct btrfsic_block *)bp->bi_private;
2251	int iodone_w_error;
2252
2253	/* mutex is not held! This is not save if IO is not yet completed
2254	 * on umount */
2255	iodone_w_error = 0;
2256	if (bio_error_status)
2257		iodone_w_error = 1;
2258
2259	BUG_ON(NULL == block);
2260	bp->bi_private = block->orig_bio_bh_private;
2261	bp->bi_end_io = block->orig_bio_bh_end_io.bio;
2262
2263	do {
2264		struct btrfsic_block *next_block;
2265		struct btrfsic_dev_state *const dev_state = block->dev_state;
2266
2267		if ((dev_state->state->print_mask &
2268		     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2269			printk(KERN_INFO
2270			       "bio_end_io(err=%d) for %c @%llu (%s/%llu/%d)\n",
2271			       bio_error_status,
2272			       btrfsic_get_block_type(dev_state->state, block),
2273			       block->logical_bytenr, dev_state->name,
2274			       block->dev_bytenr, block->mirror_num);
2275		next_block = block->next_in_same_bio;
2276		block->iodone_w_error = iodone_w_error;
2277		if (block->submit_bio_bh_rw & REQ_FLUSH) {
2278			dev_state->last_flush_gen++;
2279			if ((dev_state->state->print_mask &
2280			     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2281				printk(KERN_INFO
2282				       "bio_end_io() new %s flush_gen=%llu\n",
2283				       dev_state->name,
2284				       dev_state->last_flush_gen);
2285		}
2286		if (block->submit_bio_bh_rw & REQ_FUA)
2287			block->flush_gen = 0; /* FUA completed means block is
2288					       * on disk */
2289		block->is_iodone = 1; /* for FLUSH, this releases the block */
2290		block = next_block;
2291	} while (NULL != block);
2292
2293	bp->bi_end_io(bp, bio_error_status);
2294}
2295
2296static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate)
2297{
2298	struct btrfsic_block *block = (struct btrfsic_block *)bh->b_private;
2299	int iodone_w_error = !uptodate;
2300	struct btrfsic_dev_state *dev_state;
2301
2302	BUG_ON(NULL == block);
2303	dev_state = block->dev_state;
2304	if ((dev_state->state->print_mask & BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2305		printk(KERN_INFO
2306		       "bh_end_io(error=%d) for %c @%llu (%s/%llu/%d)\n",
2307		       iodone_w_error,
2308		       btrfsic_get_block_type(dev_state->state, block),
2309		       block->logical_bytenr, block->dev_state->name,
2310		       block->dev_bytenr, block->mirror_num);
2311
2312	block->iodone_w_error = iodone_w_error;
2313	if (block->submit_bio_bh_rw & REQ_FLUSH) {
2314		dev_state->last_flush_gen++;
2315		if ((dev_state->state->print_mask &
2316		     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2317			printk(KERN_INFO
2318			       "bh_end_io() new %s flush_gen=%llu\n",
2319			       dev_state->name, dev_state->last_flush_gen);
2320	}
2321	if (block->submit_bio_bh_rw & REQ_FUA)
2322		block->flush_gen = 0; /* FUA completed means block is on disk */
2323
2324	bh->b_private = block->orig_bio_bh_private;
2325	bh->b_end_io = block->orig_bio_bh_end_io.bh;
2326	block->is_iodone = 1; /* for FLUSH, this releases the block */
2327	bh->b_end_io(bh, uptodate);
2328}
2329
2330static int btrfsic_process_written_superblock(
2331		struct btrfsic_state *state,
2332		struct btrfsic_block *const superblock,
2333		struct btrfs_super_block *const super_hdr)
2334{
2335	int pass;
2336
2337	superblock->generation = btrfs_super_generation(super_hdr);
2338	if (!(superblock->generation > state->max_superblock_generation ||
2339	      0 == state->max_superblock_generation)) {
2340		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2341			printk(KERN_INFO
2342			       "btrfsic: superblock @%llu (%s/%llu/%d)"
2343			       " with old gen %llu <= %llu\n",
2344			       superblock->logical_bytenr,
2345			       superblock->dev_state->name,
2346			       superblock->dev_bytenr, superblock->mirror_num,
2347			       btrfs_super_generation(super_hdr),
2348			       state->max_superblock_generation);
2349	} else {
2350		if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2351			printk(KERN_INFO
2352			       "btrfsic: got new superblock @%llu (%s/%llu/%d)"
2353			       " with new gen %llu > %llu\n",
2354			       superblock->logical_bytenr,
2355			       superblock->dev_state->name,
2356			       superblock->dev_bytenr, superblock->mirror_num,
2357			       btrfs_super_generation(super_hdr),
2358			       state->max_superblock_generation);
2359
2360		state->max_superblock_generation =
2361		    btrfs_super_generation(super_hdr);
2362		state->latest_superblock = superblock;
2363	}
2364
2365	for (pass = 0; pass < 3; pass++) {
2366		int ret;
2367		u64 next_bytenr;
2368		struct btrfsic_block *next_block;
2369		struct btrfsic_block_data_ctx tmp_next_block_ctx;
2370		struct btrfsic_block_link *l;
2371		int num_copies;
2372		int mirror_num;
2373		const char *additional_string = NULL;
2374		struct btrfs_disk_key tmp_disk_key = {0};
2375
2376		btrfs_set_disk_key_objectid(&tmp_disk_key,
2377					    BTRFS_ROOT_ITEM_KEY);
2378		btrfs_set_disk_key_objectid(&tmp_disk_key, 0);
2379
2380		switch (pass) {
2381		case 0:
2382			btrfs_set_disk_key_objectid(&tmp_disk_key,
2383						    BTRFS_ROOT_TREE_OBJECTID);
2384			additional_string = "root ";
2385			next_bytenr = btrfs_super_root(super_hdr);
2386			if (state->print_mask &
2387			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2388				printk(KERN_INFO "root@%llu\n", next_bytenr);
2389			break;
2390		case 1:
2391			btrfs_set_disk_key_objectid(&tmp_disk_key,
2392						    BTRFS_CHUNK_TREE_OBJECTID);
2393			additional_string = "chunk ";
2394			next_bytenr = btrfs_super_chunk_root(super_hdr);
2395			if (state->print_mask &
2396			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2397				printk(KERN_INFO "chunk@%llu\n", next_bytenr);
2398			break;
2399		case 2:
2400			btrfs_set_disk_key_objectid(&tmp_disk_key,
2401						    BTRFS_TREE_LOG_OBJECTID);
2402			additional_string = "log ";
2403			next_bytenr = btrfs_super_log_root(super_hdr);
2404			if (0 == next_bytenr)
2405				continue;
2406			if (state->print_mask &
2407			    BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2408				printk(KERN_INFO "log@%llu\n", next_bytenr);
2409			break;
2410		}
2411
2412		num_copies =
2413		    btrfs_num_copies(state->root->fs_info,
2414				     next_bytenr, BTRFS_SUPER_INFO_SIZE);
2415		if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
2416			printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
2417			       next_bytenr, num_copies);
2418		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2419			int was_created;
2420
2421			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2422				printk(KERN_INFO
2423				       "btrfsic_process_written_superblock("
2424				       "mirror_num=%d)\n", mirror_num);
2425			ret = btrfsic_map_block(state, next_bytenr,
2426						BTRFS_SUPER_INFO_SIZE,
2427						&tmp_next_block_ctx,
2428						mirror_num);
2429			if (ret) {
2430				printk(KERN_INFO
2431				       "btrfsic: btrfsic_map_block(@%llu,"
2432				       " mirror=%d) failed!\n",
2433				       next_bytenr, mirror_num);
2434				return -1;
2435			}
2436
2437			next_block = btrfsic_block_lookup_or_add(
2438					state,
2439					&tmp_next_block_ctx,
2440					additional_string,
2441					1, 0, 1,
2442					mirror_num,
2443					&was_created);
2444			if (NULL == next_block) {
2445				printk(KERN_INFO
2446				       "btrfsic: error, kmalloc failed!\n");
2447				btrfsic_release_block_ctx(&tmp_next_block_ctx);
2448				return -1;
2449			}
2450
2451			next_block->disk_key = tmp_disk_key;
2452			if (was_created)
2453				next_block->generation =
2454				    BTRFSIC_GENERATION_UNKNOWN;
2455			l = btrfsic_block_link_lookup_or_add(
2456					state,
2457					&tmp_next_block_ctx,
2458					next_block,
2459					superblock,
2460					BTRFSIC_GENERATION_UNKNOWN);
2461			btrfsic_release_block_ctx(&tmp_next_block_ctx);
2462			if (NULL == l)
2463				return -1;
2464		}
2465	}
2466
2467	if (WARN_ON(-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)))
2468		btrfsic_dump_tree(state);
2469
2470	return 0;
2471}
2472
2473static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
2474					struct btrfsic_block *const block,
2475					int recursion_level)
2476{
2477	struct list_head *elem_ref_to;
2478	int ret = 0;
2479
2480	if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2481		/*
2482		 * Note that this situation can happen and does not
2483		 * indicate an error in regular cases. It happens
2484		 * when disk blocks are freed and later reused.
2485		 * The check-integrity module is not aware of any
2486		 * block free operations, it just recognizes block
2487		 * write operations. Therefore it keeps the linkage
2488		 * information for a block until a block is
2489		 * rewritten. This can temporarily cause incorrect
2490		 * and even circular linkage informations. This
2491		 * causes no harm unless such blocks are referenced
2492		 * by the most recent super block.
2493		 */
2494		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2495			printk(KERN_INFO
2496			       "btrfsic: abort cyclic linkage (case 1).\n");
2497
2498		return ret;
2499	}
2500
2501	/*
2502	 * This algorithm is recursive because the amount of used stack
2503	 * space is very small and the max recursion depth is limited.
2504	 */
2505	list_for_each(elem_ref_to, &block->ref_to_list) {
2506		const struct btrfsic_block_link *const l =
2507		    list_entry(elem_ref_to, struct btrfsic_block_link,
2508			       node_ref_to);
2509
2510		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2511			printk(KERN_INFO
2512			       "rl=%d, %c @%llu (%s/%llu/%d)"
2513			       " %u* refers to %c @%llu (%s/%llu/%d)\n",
2514			       recursion_level,
2515			       btrfsic_get_block_type(state, block),
2516			       block->logical_bytenr, block->dev_state->name,
2517			       block->dev_bytenr, block->mirror_num,
2518			       l->ref_cnt,
2519			       btrfsic_get_block_type(state, l->block_ref_to),
2520			       l->block_ref_to->logical_bytenr,
2521			       l->block_ref_to->dev_state->name,
2522			       l->block_ref_to->dev_bytenr,
2523			       l->block_ref_to->mirror_num);
2524		if (l->block_ref_to->never_written) {
2525			printk(KERN_INFO "btrfs: attempt to write superblock"
2526			       " which references block %c @%llu (%s/%llu/%d)"
2527			       " which is never written!\n",
2528			       btrfsic_get_block_type(state, l->block_ref_to),
2529			       l->block_ref_to->logical_bytenr,
2530			       l->block_ref_to->dev_state->name,
2531			       l->block_ref_to->dev_bytenr,
2532			       l->block_ref_to->mirror_num);
2533			ret = -1;
2534		} else if (!l->block_ref_to->is_iodone) {
2535			printk(KERN_INFO "btrfs: attempt to write superblock"
2536			       " which references block %c @%llu (%s/%llu/%d)"
2537			       " which is not yet iodone!\n",
2538			       btrfsic_get_block_type(state, l->block_ref_to),
2539			       l->block_ref_to->logical_bytenr,
2540			       l->block_ref_to->dev_state->name,
2541			       l->block_ref_to->dev_bytenr,
2542			       l->block_ref_to->mirror_num);
2543			ret = -1;
2544		} else if (l->block_ref_to->iodone_w_error) {
2545			printk(KERN_INFO "btrfs: attempt to write superblock"
2546			       " which references block %c @%llu (%s/%llu/%d)"
2547			       " which has write error!\n",
2548			       btrfsic_get_block_type(state, l->block_ref_to),
2549			       l->block_ref_to->logical_bytenr,
2550			       l->block_ref_to->dev_state->name,
2551			       l->block_ref_to->dev_bytenr,
2552			       l->block_ref_to->mirror_num);
2553			ret = -1;
2554		} else if (l->parent_generation !=
2555			   l->block_ref_to->generation &&
2556			   BTRFSIC_GENERATION_UNKNOWN !=
2557			   l->parent_generation &&
2558			   BTRFSIC_GENERATION_UNKNOWN !=
2559			   l->block_ref_to->generation) {
2560			printk(KERN_INFO "btrfs: attempt to write superblock"
2561			       " which references block %c @%llu (%s/%llu/%d)"
2562			       " with generation %llu !="
2563			       " parent generation %llu!\n",
2564			       btrfsic_get_block_type(state, l->block_ref_to),
2565			       l->block_ref_to->logical_bytenr,
2566			       l->block_ref_to->dev_state->name,
2567			       l->block_ref_to->dev_bytenr,
2568			       l->block_ref_to->mirror_num,
2569			       l->block_ref_to->generation,
2570			       l->parent_generation);
2571			ret = -1;
2572		} else if (l->block_ref_to->flush_gen >
2573			   l->block_ref_to->dev_state->last_flush_gen) {
2574			printk(KERN_INFO "btrfs: attempt to write superblock"
2575			       " which references block %c @%llu (%s/%llu/%d)"
2576			       " which is not flushed out of disk's write cache"
2577			       " (block flush_gen=%llu,"
2578			       " dev->flush_gen=%llu)!\n",
2579			       btrfsic_get_block_type(state, l->block_ref_to),
2580			       l->block_ref_to->logical_bytenr,
2581			       l->block_ref_to->dev_state->name,
2582			       l->block_ref_to->dev_bytenr,
2583			       l->block_ref_to->mirror_num, block->flush_gen,
2584			       l->block_ref_to->dev_state->last_flush_gen);
2585			ret = -1;
2586		} else if (-1 == btrfsic_check_all_ref_blocks(state,
2587							      l->block_ref_to,
2588							      recursion_level +
2589							      1)) {
2590			ret = -1;
2591		}
2592	}
2593
2594	return ret;
2595}
2596
2597static int btrfsic_is_block_ref_by_superblock(
2598		const struct btrfsic_state *state,
2599		const struct btrfsic_block *block,
2600		int recursion_level)
2601{
2602	struct list_head *elem_ref_from;
2603
2604	if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2605		/* refer to comment at "abort cyclic linkage (case 1)" */
2606		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2607			printk(KERN_INFO
2608			       "btrfsic: abort cyclic linkage (case 2).\n");
2609
2610		return 0;
2611	}
2612
2613	/*
2614	 * This algorithm is recursive because the amount of used stack space
2615	 * is very small and the max recursion depth is limited.
2616	 */
2617	list_for_each(elem_ref_from, &block->ref_from_list) {
2618		const struct btrfsic_block_link *const l =
2619		    list_entry(elem_ref_from, struct btrfsic_block_link,
2620			       node_ref_from);
2621
2622		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2623			printk(KERN_INFO
2624			       "rl=%d, %c @%llu (%s/%llu/%d)"
2625			       " is ref %u* from %c @%llu (%s/%llu/%d)\n",
2626			       recursion_level,
2627			       btrfsic_get_block_type(state, block),
2628			       block->logical_bytenr, block->dev_state->name,
2629			       block->dev_bytenr, block->mirror_num,
2630			       l->ref_cnt,
2631			       btrfsic_get_block_type(state, l->block_ref_from),
2632			       l->block_ref_from->logical_bytenr,
2633			       l->block_ref_from->dev_state->name,
2634			       l->block_ref_from->dev_bytenr,
2635			       l->block_ref_from->mirror_num);
2636		if (l->block_ref_from->is_superblock &&
2637		    state->latest_superblock->dev_bytenr ==
2638		    l->block_ref_from->dev_bytenr &&
2639		    state->latest_superblock->dev_state->bdev ==
2640		    l->block_ref_from->dev_state->bdev)
2641			return 1;
2642		else if (btrfsic_is_block_ref_by_superblock(state,
2643							    l->block_ref_from,
2644							    recursion_level +
2645							    1))
2646			return 1;
2647	}
2648
2649	return 0;
2650}
2651
2652static void btrfsic_print_add_link(const struct btrfsic_state *state,
2653				   const struct btrfsic_block_link *l)
2654{
2655	printk(KERN_INFO
2656	       "Add %u* link from %c @%llu (%s/%llu/%d)"
2657	       " to %c @%llu (%s/%llu/%d).\n",
2658	       l->ref_cnt,
2659	       btrfsic_get_block_type(state, l->block_ref_from),
2660	       l->block_ref_from->logical_bytenr,
2661	       l->block_ref_from->dev_state->name,
2662	       l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2663	       btrfsic_get_block_type(state, l->block_ref_to),
2664	       l->block_ref_to->logical_bytenr,
2665	       l->block_ref_to->dev_state->name, l->block_ref_to->dev_bytenr,
2666	       l->block_ref_to->mirror_num);
2667}
2668
2669static void btrfsic_print_rem_link(const struct btrfsic_state *state,
2670				   const struct btrfsic_block_link *l)
2671{
2672	printk(KERN_INFO
2673	       "Rem %u* link from %c @%llu (%s/%llu/%d)"
2674	       " to %c @%llu (%s/%llu/%d).\n",
2675	       l->ref_cnt,
2676	       btrfsic_get_block_type(state, l->block_ref_from),
2677	       l->block_ref_from->logical_bytenr,
2678	       l->block_ref_from->dev_state->name,
2679	       l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2680	       btrfsic_get_block_type(state, l->block_ref_to),
2681	       l->block_ref_to->logical_bytenr,
2682	       l->block_ref_to->dev_state->name, l->block_ref_to->dev_bytenr,
2683	       l->block_ref_to->mirror_num);
2684}
2685
2686static char btrfsic_get_block_type(const struct btrfsic_state *state,
2687				   const struct btrfsic_block *block)
2688{
2689	if (block->is_superblock &&
2690	    state->latest_superblock->dev_bytenr == block->dev_bytenr &&
2691	    state->latest_superblock->dev_state->bdev == block->dev_state->bdev)
2692		return 'S';
2693	else if (block->is_superblock)
2694		return 's';
2695	else if (block->is_metadata)
2696		return 'M';
2697	else
2698		return 'D';
2699}
2700
2701static void btrfsic_dump_tree(const struct btrfsic_state *state)
2702{
2703	btrfsic_dump_tree_sub(state, state->latest_superblock, 0);
2704}
2705
2706static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
2707				  const struct btrfsic_block *block,
2708				  int indent_level)
2709{
2710	struct list_head *elem_ref_to;
2711	int indent_add;
2712	static char buf[80];
2713	int cursor_position;
2714
2715	/*
2716	 * Should better fill an on-stack buffer with a complete line and
2717	 * dump it at once when it is time to print a newline character.
2718	 */
2719
2720	/*
2721	 * This algorithm is recursive because the amount of used stack space
2722	 * is very small and the max recursion depth is limited.
2723	 */
2724	indent_add = sprintf(buf, "%c-%llu(%s/%llu/%d)",
2725			     btrfsic_get_block_type(state, block),
2726			     block->logical_bytenr, block->dev_state->name,
2727			     block->dev_bytenr, block->mirror_num);
2728	if (indent_level + indent_add > BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2729		printk("[...]\n");
2730		return;
2731	}
2732	printk(buf);
2733	indent_level += indent_add;
2734	if (list_empty(&block->ref_to_list)) {
2735		printk("\n");
2736		return;
2737	}
2738	if (block->mirror_num > 1 &&
2739	    !(state->print_mask & BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS)) {
2740		printk(" [...]\n");
2741		return;
2742	}
2743
2744	cursor_position = indent_level;
2745	list_for_each(elem_ref_to, &block->ref_to_list) {
2746		const struct btrfsic_block_link *const l =
2747		    list_entry(elem_ref_to, struct btrfsic_block_link,
2748			       node_ref_to);
2749
2750		while (cursor_position < indent_level) {
2751			printk(" ");
2752			cursor_position++;
2753		}
2754		if (l->ref_cnt > 1)
2755			indent_add = sprintf(buf, " %d*--> ", l->ref_cnt);
2756		else
2757			indent_add = sprintf(buf, " --> ");
2758		if (indent_level + indent_add >
2759		    BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2760			printk("[...]\n");
2761			cursor_position = 0;
2762			continue;
2763		}
2764
2765		printk(buf);
2766
2767		btrfsic_dump_tree_sub(state, l->block_ref_to,
2768				      indent_level + indent_add);
2769		cursor_position = 0;
2770	}
2771}
2772
2773static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
2774		struct btrfsic_state *state,
2775		struct btrfsic_block_data_ctx *next_block_ctx,
2776		struct btrfsic_block *next_block,
2777		struct btrfsic_block *from_block,
2778		u64 parent_generation)
2779{
2780	struct btrfsic_block_link *l;
2781
2782	l = btrfsic_block_link_hashtable_lookup(next_block_ctx->dev->bdev,
2783						next_block_ctx->dev_bytenr,
2784						from_block->dev_state->bdev,
2785						from_block->dev_bytenr,
2786						&state->block_link_hashtable);
2787	if (NULL == l) {
2788		l = btrfsic_block_link_alloc();
2789		if (NULL == l) {
2790			printk(KERN_INFO
2791			       "btrfsic: error, kmalloc" " failed!\n");
2792			return NULL;
2793		}
2794
2795		l->block_ref_to = next_block;
2796		l->block_ref_from = from_block;
2797		l->ref_cnt = 1;
2798		l->parent_generation = parent_generation;
2799
2800		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2801			btrfsic_print_add_link(state, l);
2802
2803		list_add(&l->node_ref_to, &from_block->ref_to_list);
2804		list_add(&l->node_ref_from, &next_block->ref_from_list);
2805
2806		btrfsic_block_link_hashtable_add(l,
2807						 &state->block_link_hashtable);
2808	} else {
2809		l->ref_cnt++;
2810		l->parent_generation = parent_generation;
2811		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2812			btrfsic_print_add_link(state, l);
2813	}
2814
2815	return l;
2816}
2817
2818static struct btrfsic_block *btrfsic_block_lookup_or_add(
2819		struct btrfsic_state *state,
2820		struct btrfsic_block_data_ctx *block_ctx,
2821		const char *additional_string,
2822		int is_metadata,
2823		int is_iodone,
2824		int never_written,
2825		int mirror_num,
2826		int *was_created)
2827{
2828	struct btrfsic_block *block;
2829
2830	block = btrfsic_block_hashtable_lookup(block_ctx->dev->bdev,
2831					       block_ctx->dev_bytenr,
2832					       &state->block_hashtable);
2833	if (NULL == block) {
2834		struct btrfsic_dev_state *dev_state;
2835
2836		block = btrfsic_block_alloc();
2837		if (NULL == block) {
2838			printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2839			return NULL;
2840		}
2841		dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev);
2842		if (NULL == dev_state) {
2843			printk(KERN_INFO
2844			       "btrfsic: error, lookup dev_state failed!\n");
2845			btrfsic_block_free(block);
2846			return NULL;
2847		}
2848		block->dev_state = dev_state;
2849		block->dev_bytenr = block_ctx->dev_bytenr;
2850		block->logical_bytenr = block_ctx->start;
2851		block->is_metadata = is_metadata;
2852		block->is_iodone = is_iodone;
2853		block->never_written = never_written;
2854		block->mirror_num = mirror_num;
2855		if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2856			printk(KERN_INFO
2857			       "New %s%c-block @%llu (%s/%llu/%d)\n",
2858			       additional_string,
2859			       btrfsic_get_block_type(state, block),
2860			       block->logical_bytenr, dev_state->name,
2861			       block->dev_bytenr, mirror_num);
2862		list_add(&block->all_blocks_node, &state->all_blocks_list);
2863		btrfsic_block_hashtable_add(block, &state->block_hashtable);
2864		if (NULL != was_created)
2865			*was_created = 1;
2866	} else {
2867		if (NULL != was_created)
2868			*was_created = 0;
2869	}
2870
2871	return block;
2872}
2873
2874static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
2875					   u64 bytenr,
2876					   struct btrfsic_dev_state *dev_state,
2877					   u64 dev_bytenr)
2878{
2879	int num_copies;
2880	int mirror_num;
2881	int ret;
2882	struct btrfsic_block_data_ctx block_ctx;
2883	int match = 0;
2884
2885	num_copies = btrfs_num_copies(state->root->fs_info,
2886				      bytenr, state->metablock_size);
2887
2888	for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2889		ret = btrfsic_map_block(state, bytenr, state->metablock_size,
2890					&block_ctx, mirror_num);
2891		if (ret) {
2892			printk(KERN_INFO "btrfsic:"
2893			       " btrfsic_map_block(logical @%llu,"
2894			       " mirror %d) failed!\n",
2895			       bytenr, mirror_num);
2896			continue;
2897		}
2898
2899		if (dev_state->bdev == block_ctx.dev->bdev &&
2900		    dev_bytenr == block_ctx.dev_bytenr) {
2901			match++;
2902			btrfsic_release_block_ctx(&block_ctx);
2903			break;
2904		}
2905		btrfsic_release_block_ctx(&block_ctx);
2906	}
2907
2908	if (WARN_ON(!match)) {
2909		printk(KERN_INFO "btrfs: attempt to write M-block which contains logical bytenr that doesn't map to dev+physical bytenr of submit_bio,"
2910		       " buffer->log_bytenr=%llu, submit_bio(bdev=%s,"
2911		       " phys_bytenr=%llu)!\n",
2912		       bytenr, dev_state->name, dev_bytenr);
2913		for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2914			ret = btrfsic_map_block(state, bytenr,
2915						state->metablock_size,
2916						&block_ctx, mirror_num);
2917			if (ret)
2918				continue;
2919
2920			printk(KERN_INFO "Read logical bytenr @%llu maps to"
2921			       " (%s/%llu/%d)\n",
2922			       bytenr, block_ctx.dev->name,
2923			       block_ctx.dev_bytenr, mirror_num);
2924		}
2925	}
2926}
2927
2928static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
2929		struct block_device *bdev)
2930{
2931	struct btrfsic_dev_state *ds;
2932
2933	ds = btrfsic_dev_state_hashtable_lookup(bdev,
2934						&btrfsic_dev_state_hashtable);
2935	return ds;
2936}
2937
2938int btrfsic_submit_bh(int rw, struct buffer_head *bh)
2939{
2940	struct btrfsic_dev_state *dev_state;
2941
2942	if (!btrfsic_is_initialized)
2943		return submit_bh(rw, bh);
2944
2945	mutex_lock(&btrfsic_mutex);
2946	/* since btrfsic_submit_bh() might also be called before
2947	 * btrfsic_mount(), this might return NULL */
2948	dev_state = btrfsic_dev_state_lookup(bh->b_bdev);
2949
2950	/* Only called to write the superblock (incl. FLUSH/FUA) */
2951	if (NULL != dev_state &&
2952	    (rw & WRITE) && bh->b_size > 0) {
2953		u64 dev_bytenr;
2954
2955		dev_bytenr = 4096 * bh->b_blocknr;
2956		if (dev_state->state->print_mask &
2957		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2958			printk(KERN_INFO
2959			       "submit_bh(rw=0x%x, blocknr=%llu (bytenr %llu),"
2960			       " size=%zu, data=%p, bdev=%p)\n",
2961			       rw, (unsigned long long)bh->b_blocknr,
2962			       dev_bytenr, bh->b_size, bh->b_data, bh->b_bdev);
2963		btrfsic_process_written_block(dev_state, dev_bytenr,
2964					      &bh->b_data, 1, NULL,
2965					      NULL, bh, rw);
2966	} else if (NULL != dev_state && (rw & REQ_FLUSH)) {
2967		if (dev_state->state->print_mask &
2968		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2969			printk(KERN_INFO
2970			       "submit_bh(rw=0x%x FLUSH, bdev=%p)\n",
2971			       rw, bh->b_bdev);
2972		if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
2973			if ((dev_state->state->print_mask &
2974			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2975			      BTRFSIC_PRINT_MASK_VERBOSE)))
2976				printk(KERN_INFO
2977				       "btrfsic_submit_bh(%s) with FLUSH"
2978				       " but dummy block already in use"
2979				       " (ignored)!\n",
2980				       dev_state->name);
2981		} else {
2982			struct btrfsic_block *const block =
2983				&dev_state->dummy_block_for_bio_bh_flush;
2984
2985			block->is_iodone = 0;
2986			block->never_written = 0;
2987			block->iodone_w_error = 0;
2988			block->flush_gen = dev_state->last_flush_gen + 1;
2989			block->submit_bio_bh_rw = rw;
2990			block->orig_bio_bh_private = bh->b_private;
2991			block->orig_bio_bh_end_io.bh = bh->b_end_io;
2992			block->next_in_same_bio = NULL;
2993			bh->b_private = block;
2994			bh->b_end_io = btrfsic_bh_end_io;
2995		}
2996	}
2997	mutex_unlock(&btrfsic_mutex);
2998	return submit_bh(rw, bh);
2999}
3000
3001static void __btrfsic_submit_bio(int rw, struct bio *bio)
3002{
3003	struct btrfsic_dev_state *dev_state;
3004
3005	if (!btrfsic_is_initialized)
3006		return;
3007
3008	mutex_lock(&btrfsic_mutex);
3009	/* since btrfsic_submit_bio() is also called before
3010	 * btrfsic_mount(), this might return NULL */
3011	dev_state = btrfsic_dev_state_lookup(bio->bi_bdev);
3012	if (NULL != dev_state &&
3013	    (rw & WRITE) && NULL != bio->bi_io_vec) {
3014		unsigned int i;
3015		u64 dev_bytenr;
3016		u64 cur_bytenr;
3017		int bio_is_patched;
3018		char **mapped_datav;
3019
3020		dev_bytenr = 512 * bio->bi_iter.bi_sector;
3021		bio_is_patched = 0;
3022		if (dev_state->state->print_mask &
3023		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3024			printk(KERN_INFO
3025			       "submit_bio(rw=0x%x, bi_vcnt=%u,"
3026			       " bi_sector=%llu (bytenr %llu), bi_bdev=%p)\n",
3027			       rw, bio->bi_vcnt,
3028			       (unsigned long long)bio->bi_iter.bi_sector,
3029			       dev_bytenr, bio->bi_bdev);
3030
3031		mapped_datav = kmalloc(sizeof(*mapped_datav) * bio->bi_vcnt,
3032				       GFP_NOFS);
3033		if (!mapped_datav)
3034			goto leave;
3035		cur_bytenr = dev_bytenr;
3036		for (i = 0; i < bio->bi_vcnt; i++) {
3037			BUG_ON(bio->bi_io_vec[i].bv_len != PAGE_CACHE_SIZE);
3038			mapped_datav[i] = kmap(bio->bi_io_vec[i].bv_page);
3039			if (!mapped_datav[i]) {
3040				while (i > 0) {
3041					i--;
3042					kunmap(bio->bi_io_vec[i].bv_page);
3043				}
3044				kfree(mapped_datav);
3045				goto leave;
3046			}
3047			if (dev_state->state->print_mask &
3048			    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE)
3049				printk(KERN_INFO
3050				       "#%u: bytenr=%llu, len=%u, offset=%u\n",
3051				       i, cur_bytenr, bio->bi_io_vec[i].bv_len,
3052				       bio->bi_io_vec[i].bv_offset);
3053			cur_bytenr += bio->bi_io_vec[i].bv_len;
3054		}
3055		btrfsic_process_written_block(dev_state, dev_bytenr,
3056					      mapped_datav, bio->bi_vcnt,
3057					      bio, &bio_is_patched,
3058					      NULL, rw);
3059		while (i > 0) {
3060			i--;
3061			kunmap(bio->bi_io_vec[i].bv_page);
3062		}
3063		kfree(mapped_datav);
3064	} else if (NULL != dev_state && (rw & REQ_FLUSH)) {
3065		if (dev_state->state->print_mask &
3066		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3067			printk(KERN_INFO
3068			       "submit_bio(rw=0x%x FLUSH, bdev=%p)\n",
3069			       rw, bio->bi_bdev);
3070		if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
3071			if ((dev_state->state->print_mask &
3072			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3073			      BTRFSIC_PRINT_MASK_VERBOSE)))
3074				printk(KERN_INFO
3075				       "btrfsic_submit_bio(%s) with FLUSH"
3076				       " but dummy block already in use"
3077				       " (ignored)!\n",
3078				       dev_state->name);
3079		} else {
3080			struct btrfsic_block *const block =
3081				&dev_state->dummy_block_for_bio_bh_flush;
3082
3083			block->is_iodone = 0;
3084			block->never_written = 0;
3085			block->iodone_w_error = 0;
3086			block->flush_gen = dev_state->last_flush_gen + 1;
3087			block->submit_bio_bh_rw = rw;
3088			block->orig_bio_bh_private = bio->bi_private;
3089			block->orig_bio_bh_end_io.bio = bio->bi_end_io;
3090			block->next_in_same_bio = NULL;
3091			bio->bi_private = block;
3092			bio->bi_end_io = btrfsic_bio_end_io;
3093		}
3094	}
3095leave:
3096	mutex_unlock(&btrfsic_mutex);
3097}
3098
3099void btrfsic_submit_bio(int rw, struct bio *bio)
3100{
3101	__btrfsic_submit_bio(rw, bio);
3102	submit_bio(rw, bio);
3103}
3104
3105int btrfsic_submit_bio_wait(int rw, struct bio *bio)
3106{
3107	__btrfsic_submit_bio(rw, bio);
3108	return submit_bio_wait(rw, bio);
3109}
3110
3111int btrfsic_mount(struct btrfs_root *root,
3112		  struct btrfs_fs_devices *fs_devices,
3113		  int including_extent_data, u32 print_mask)
3114{
3115	int ret;
3116	struct btrfsic_state *state;
3117	struct list_head *dev_head = &fs_devices->devices;
3118	struct btrfs_device *device;
3119
3120	if (root->nodesize != root->leafsize) {
3121		printk(KERN_INFO
3122		       "btrfsic: cannot handle nodesize %d != leafsize %d!\n",
3123		       root->nodesize, root->leafsize);
3124		return -1;
3125	}
3126	if (root->nodesize & ((u64)PAGE_CACHE_SIZE - 1)) {
3127		printk(KERN_INFO
3128		       "btrfsic: cannot handle nodesize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3129		       root->nodesize, PAGE_CACHE_SIZE);
3130		return -1;
3131	}
3132	if (root->leafsize & ((u64)PAGE_CACHE_SIZE - 1)) {
3133		printk(KERN_INFO
3134		       "btrfsic: cannot handle leafsize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3135		       root->leafsize, PAGE_CACHE_SIZE);
3136		return -1;
3137	}
3138	if (root->sectorsize & ((u64)PAGE_CACHE_SIZE - 1)) {
3139		printk(KERN_INFO
3140		       "btrfsic: cannot handle sectorsize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3141		       root->sectorsize, PAGE_CACHE_SIZE);
3142		return -1;
3143	}
3144	state = kzalloc(sizeof(*state), GFP_NOFS);
3145	if (NULL == state) {
3146		printk(KERN_INFO "btrfs check-integrity: kmalloc() failed!\n");
3147		return -1;
3148	}
3149
3150	if (!btrfsic_is_initialized) {
3151		mutex_init(&btrfsic_mutex);
3152		btrfsic_dev_state_hashtable_init(&btrfsic_dev_state_hashtable);
3153		btrfsic_is_initialized = 1;
3154	}
3155	mutex_lock(&btrfsic_mutex);
3156	state->root = root;
3157	state->print_mask = print_mask;
3158	state->include_extent_data = including_extent_data;
3159	state->csum_size = 0;
3160	state->metablock_size = root->nodesize;
3161	state->datablock_size = root->sectorsize;
3162	INIT_LIST_HEAD(&state->all_blocks_list);
3163	btrfsic_block_hashtable_init(&state->block_hashtable);
3164	btrfsic_block_link_hashtable_init(&state->block_link_hashtable);
3165	state->max_superblock_generation = 0;
3166	state->latest_superblock = NULL;
3167
3168	list_for_each_entry(device, dev_head, dev_list) {
3169		struct btrfsic_dev_state *ds;
3170		char *p;
3171
3172		if (!device->bdev || !device->name)
3173			continue;
3174
3175		ds = btrfsic_dev_state_alloc();
3176		if (NULL == ds) {
3177			printk(KERN_INFO
3178			       "btrfs check-integrity: kmalloc() failed!\n");
3179			mutex_unlock(&btrfsic_mutex);
3180			return -1;
3181		}
3182		ds->bdev = device->bdev;
3183		ds->state = state;
3184		bdevname(ds->bdev, ds->name);
3185		ds->name[BDEVNAME_SIZE - 1] = '\0';
3186		for (p = ds->name; *p != '\0'; p++);
3187		while (p > ds->name && *p != '/')
3188			p--;
3189		if (*p == '/')
3190			p++;
3191		strlcpy(ds->name, p, sizeof(ds->name));
3192		btrfsic_dev_state_hashtable_add(ds,
3193						&btrfsic_dev_state_hashtable);
3194	}
3195
3196	ret = btrfsic_process_superblock(state, fs_devices);
3197	if (0 != ret) {
3198		mutex_unlock(&btrfsic_mutex);
3199		btrfsic_unmount(root, fs_devices);
3200		return ret;
3201	}
3202
3203	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_DATABASE)
3204		btrfsic_dump_database(state);
3205	if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_TREE)
3206		btrfsic_dump_tree(state);
3207
3208	mutex_unlock(&btrfsic_mutex);
3209	return 0;
3210}
3211
3212void btrfsic_unmount(struct btrfs_root *root,
3213		     struct btrfs_fs_devices *fs_devices)
3214{
3215	struct list_head *elem_all;
3216	struct list_head *tmp_all;
3217	struct btrfsic_state *state;
3218	struct list_head *dev_head = &fs_devices->devices;
3219	struct btrfs_device *device;
3220
3221	if (!btrfsic_is_initialized)
3222		return;
3223
3224	mutex_lock(&btrfsic_mutex);
3225
3226	state = NULL;
3227	list_for_each_entry(device, dev_head, dev_list) {
3228		struct btrfsic_dev_state *ds;
3229
3230		if (!device->bdev || !device->name)
3231			continue;
3232
3233		ds = btrfsic_dev_state_hashtable_lookup(
3234				device->bdev,
3235				&btrfsic_dev_state_hashtable);
3236		if (NULL != ds) {
3237			state = ds->state;
3238			btrfsic_dev_state_hashtable_remove(ds);
3239			btrfsic_dev_state_free(ds);
3240		}
3241	}
3242
3243	if (NULL == state) {
3244		printk(KERN_INFO
3245		       "btrfsic: error, cannot find state information"
3246		       " on umount!\n");
3247		mutex_unlock(&btrfsic_mutex);
3248		return;
3249	}
3250
3251	/*
3252	 * Don't care about keeping the lists' state up to date,
3253	 * just free all memory that was allocated dynamically.
3254	 * Free the blocks and the block_links.
3255	 */
3256	list_for_each_safe(elem_all, tmp_all, &state->all_blocks_list) {
3257		struct btrfsic_block *const b_all =
3258		    list_entry(elem_all, struct btrfsic_block,
3259			       all_blocks_node);
3260		struct list_head *elem_ref_to;
3261		struct list_head *tmp_ref_to;
3262
3263		list_for_each_safe(elem_ref_to, tmp_ref_to,
3264				   &b_all->ref_to_list) {
3265			struct btrfsic_block_link *const l =
3266			    list_entry(elem_ref_to,
3267				       struct btrfsic_block_link,
3268				       node_ref_to);
3269
3270			if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
3271				btrfsic_print_rem_link(state, l);
3272
3273			l->ref_cnt--;
3274			if (0 == l->ref_cnt)
3275				btrfsic_block_link_free(l);
3276		}
3277
3278		if (b_all->is_iodone || b_all->never_written)
3279			btrfsic_block_free(b_all);
3280		else
3281			printk(KERN_INFO "btrfs: attempt to free %c-block"
3282			       " @%llu (%s/%llu/%d) on umount which is"
3283			       " not yet iodone!\n",
3284			       btrfsic_get_block_type(state, b_all),
3285			       b_all->logical_bytenr, b_all->dev_state->name,
3286			       b_all->dev_bytenr, b_all->mirror_num);
3287	}
3288
3289	mutex_unlock(&btrfsic_mutex);
3290
3291	kfree(state);
3292}