linux/fs/btrfs/check-integrity.c
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   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
  82#include <linux/sched.h>
  83#include <linux/slab.h>
  84#include <linux/buffer_head.h>
  85#include <linux/mutex.h>
  86#include <linux/crc32c.h>
  87#include <linux/genhd.h>
  88#include <linux/blkdev.h>
  89#include "ctree.h"
  90#include "disk-io.h"
  91#include "transaction.h"
  92#include "extent_io.h"
  93#include "volumes.h"
  94#include "print-tree.h"
  95#include "locking.h"
  96#include "check-integrity.h"
  97#include "rcu-string.h"
  98
  99#define BTRFSIC_BLOCK_HASHTABLE_SIZE 0x10000
 100#define BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE 0x10000
 101#define BTRFSIC_DEV2STATE_HASHTABLE_SIZE 0x100
 102#define BTRFSIC_BLOCK_MAGIC_NUMBER 0x14491051
 103#define BTRFSIC_BLOCK_LINK_MAGIC_NUMBER 0x11070807
 104#define BTRFSIC_DEV2STATE_MAGIC_NUMBER 0x20111530
 105#define BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER 20111300
 106#define BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL (200 - 6)    /* in characters,
 107                                                         * excluding " [...]" */
 108#define BTRFSIC_GENERATION_UNKNOWN ((u64)-1)
 109
 110/*
 111 * The definition of the bitmask fields for the print_mask.
 112 * They are specified with the mount option check_integrity_print_mask.
 113 */
 114#define BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE                     0x00000001
 115#define BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION         0x00000002
 116#define BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE                  0x00000004
 117#define BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE                 0x00000008
 118#define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH                        0x00000010
 119#define BTRFSIC_PRINT_MASK_END_IO_BIO_BH                        0x00000020
 120#define BTRFSIC_PRINT_MASK_VERBOSE                              0x00000040
 121#define BTRFSIC_PRINT_MASK_VERY_VERBOSE                         0x00000080
 122#define BTRFSIC_PRINT_MASK_INITIAL_TREE                         0x00000100
 123#define BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES                    0x00000200
 124#define BTRFSIC_PRINT_MASK_INITIAL_DATABASE                     0x00000400
 125#define BTRFSIC_PRINT_MASK_NUM_COPIES                           0x00000800
 126#define BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS                0x00001000
 127
 128struct btrfsic_dev_state;
 129struct btrfsic_state;
 130
 131struct btrfsic_block {
 132        u32 magic_num;          /* only used for debug purposes */
 133        unsigned int is_metadata:1;     /* if it is meta-data, not data-data */
 134        unsigned int is_superblock:1;   /* if it is one of the superblocks */
 135        unsigned int is_iodone:1;       /* if is done by lower subsystem */
 136        unsigned int iodone_w_error:1;  /* error was indicated to endio */
 137        unsigned int never_written:1;   /* block was added because it was
 138                                         * referenced, not because it was
 139                                         * written */
 140        unsigned int mirror_num:2;      /* large enough to hold
 141                                         * BTRFS_SUPER_MIRROR_MAX */
 142        struct btrfsic_dev_state *dev_state;
 143        u64 dev_bytenr;         /* key, physical byte num on disk */
 144        u64 logical_bytenr;     /* logical byte num on disk */
 145        u64 generation;
 146        struct btrfs_disk_key disk_key; /* extra info to print in case of
 147                                         * issues, will not always be correct */
 148        struct list_head collision_resolving_node;      /* list node */
 149        struct list_head all_blocks_node;       /* list node */
 150
 151        /* the following two lists contain block_link items */
 152        struct list_head ref_to_list;   /* list */
 153        struct list_head ref_from_list; /* list */
 154        struct btrfsic_block *next_in_same_bio;
 155        void *orig_bio_bh_private;
 156        union {
 157                bio_end_io_t *bio;
 158                bh_end_io_t *bh;
 159        } orig_bio_bh_end_io;
 160        int submit_bio_bh_rw;
 161        u64 flush_gen; /* only valid if !never_written */
 162};
 163
 164/*
 165 * Elements of this type are allocated dynamically and required because
 166 * each block object can refer to and can be ref from multiple blocks.
 167 * The key to lookup them in the hashtable is the dev_bytenr of
 168 * the block ref to plus the one from the block refered from.
 169 * The fact that they are searchable via a hashtable and that a
 170 * ref_cnt is maintained is not required for the btrfs integrity
 171 * check algorithm itself, it is only used to make the output more
 172 * beautiful in case that an error is detected (an error is defined
 173 * as a write operation to a block while that block is still referenced).
 174 */
 175struct btrfsic_block_link {
 176        u32 magic_num;          /* only used for debug purposes */
 177        u32 ref_cnt;
 178        struct list_head node_ref_to;   /* list node */
 179        struct list_head node_ref_from; /* list node */
 180        struct list_head collision_resolving_node;      /* list node */
 181        struct btrfsic_block *block_ref_to;
 182        struct btrfsic_block *block_ref_from;
 183        u64 parent_generation;
 184};
 185
 186struct btrfsic_dev_state {
 187        u32 magic_num;          /* only used for debug purposes */
 188        struct block_device *bdev;
 189        struct btrfsic_state *state;
 190        struct list_head collision_resolving_node;      /* list node */
 191        struct btrfsic_block dummy_block_for_bio_bh_flush;
 192        u64 last_flush_gen;
 193        char name[BDEVNAME_SIZE];
 194};
 195
 196struct btrfsic_block_hashtable {
 197        struct list_head table[BTRFSIC_BLOCK_HASHTABLE_SIZE];
 198};
 199
 200struct btrfsic_block_link_hashtable {
 201        struct list_head table[BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE];
 202};
 203
 204struct btrfsic_dev_state_hashtable {
 205        struct list_head table[BTRFSIC_DEV2STATE_HASHTABLE_SIZE];
 206};
 207
 208struct btrfsic_block_data_ctx {
 209        u64 start;              /* virtual bytenr */
 210        u64 dev_bytenr;         /* physical bytenr on device */
 211        u32 len;
 212        struct btrfsic_dev_state *dev;
 213        char **datav;
 214        struct page **pagev;
 215        void *mem_to_free;
 216};
 217
 218/* This structure is used to implement recursion without occupying
 219 * any stack space, refer to btrfsic_process_metablock() */
 220struct btrfsic_stack_frame {
 221        u32 magic;
 222        u32 nr;
 223        int error;
 224        int i;
 225        int limit_nesting;
 226        int num_copies;
 227        int mirror_num;
 228        struct btrfsic_block *block;
 229        struct btrfsic_block_data_ctx *block_ctx;
 230        struct btrfsic_block *next_block;
 231        struct btrfsic_block_data_ctx next_block_ctx;
 232        struct btrfs_header *hdr;
 233        struct btrfsic_stack_frame *prev;
 234};
 235
 236/* Some state per mounted filesystem */
 237struct btrfsic_state {
 238        u32 print_mask;
 239        int include_extent_data;
 240        int csum_size;
 241        struct list_head all_blocks_list;
 242        struct btrfsic_block_hashtable block_hashtable;
 243        struct btrfsic_block_link_hashtable block_link_hashtable;
 244        struct btrfs_root *root;
 245        u64 max_superblock_generation;
 246        struct btrfsic_block *latest_superblock;
 247        u32 metablock_size;
 248        u32 datablock_size;
 249};
 250
 251static void btrfsic_block_init(struct btrfsic_block *b);
 252static struct btrfsic_block *btrfsic_block_alloc(void);
 253static void btrfsic_block_free(struct btrfsic_block *b);
 254static void btrfsic_block_link_init(struct btrfsic_block_link *n);
 255static struct btrfsic_block_link *btrfsic_block_link_alloc(void);
 256static void btrfsic_block_link_free(struct btrfsic_block_link *n);
 257static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds);
 258static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void);
 259static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds);
 260static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h);
 261static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
 262                                        struct btrfsic_block_hashtable *h);
 263static void btrfsic_block_hashtable_remove(struct btrfsic_block *b);
 264static struct btrfsic_block *btrfsic_block_hashtable_lookup(
 265                struct block_device *bdev,
 266                u64 dev_bytenr,
 267                struct btrfsic_block_hashtable *h);
 268static void btrfsic_block_link_hashtable_init(
 269                struct btrfsic_block_link_hashtable *h);
 270static void btrfsic_block_link_hashtable_add(
 271                struct btrfsic_block_link *l,
 272                struct btrfsic_block_link_hashtable *h);
 273static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l);
 274static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
 275                struct block_device *bdev_ref_to,
 276                u64 dev_bytenr_ref_to,
 277                struct block_device *bdev_ref_from,
 278                u64 dev_bytenr_ref_from,
 279                struct btrfsic_block_link_hashtable *h);
 280static void btrfsic_dev_state_hashtable_init(
 281                struct btrfsic_dev_state_hashtable *h);
 282static void btrfsic_dev_state_hashtable_add(
 283                struct btrfsic_dev_state *ds,
 284                struct btrfsic_dev_state_hashtable *h);
 285static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds);
 286static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
 287                struct block_device *bdev,
 288                struct btrfsic_dev_state_hashtable *h);
 289static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void);
 290static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf);
 291static int btrfsic_process_superblock(struct btrfsic_state *state,
 292                                      struct btrfs_fs_devices *fs_devices);
 293static int btrfsic_process_metablock(struct btrfsic_state *state,
 294                                     struct btrfsic_block *block,
 295                                     struct btrfsic_block_data_ctx *block_ctx,
 296                                     int limit_nesting, int force_iodone_flag);
 297static void btrfsic_read_from_block_data(
 298        struct btrfsic_block_data_ctx *block_ctx,
 299        void *dst, u32 offset, size_t len);
 300static int btrfsic_create_link_to_next_block(
 301                struct btrfsic_state *state,
 302                struct btrfsic_block *block,
 303                struct btrfsic_block_data_ctx
 304                *block_ctx, u64 next_bytenr,
 305                int limit_nesting,
 306                struct btrfsic_block_data_ctx *next_block_ctx,
 307                struct btrfsic_block **next_blockp,
 308                int force_iodone_flag,
 309                int *num_copiesp, int *mirror_nump,
 310                struct btrfs_disk_key *disk_key,
 311                u64 parent_generation);
 312static int btrfsic_handle_extent_data(struct btrfsic_state *state,
 313                                      struct btrfsic_block *block,
 314                                      struct btrfsic_block_data_ctx *block_ctx,
 315                                      u32 item_offset, int force_iodone_flag);
 316static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
 317                             struct btrfsic_block_data_ctx *block_ctx_out,
 318                             int mirror_num);
 319static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
 320                                  u32 len, struct block_device *bdev,
 321                                  struct btrfsic_block_data_ctx *block_ctx_out);
 322static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx);
 323static int btrfsic_read_block(struct btrfsic_state *state,
 324                              struct btrfsic_block_data_ctx *block_ctx);
 325static void btrfsic_dump_database(struct btrfsic_state *state);
 326static void btrfsic_complete_bio_end_io(struct bio *bio, int err);
 327static int btrfsic_test_for_metadata(struct btrfsic_state *state,
 328                                     char **datav, unsigned int num_pages);
 329static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
 330                                          u64 dev_bytenr, char **mapped_datav,
 331                                          unsigned int num_pages,
 332                                          struct bio *bio, int *bio_is_patched,
 333                                          struct buffer_head *bh,
 334                                          int submit_bio_bh_rw);
 335static int btrfsic_process_written_superblock(
 336                struct btrfsic_state *state,
 337                struct btrfsic_block *const block,
 338                struct btrfs_super_block *const super_hdr);
 339static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status);
 340static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate);
 341static int btrfsic_is_block_ref_by_superblock(const struct btrfsic_state *state,
 342                                              const struct btrfsic_block *block,
 343                                              int recursion_level);
 344static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
 345                                        struct btrfsic_block *const block,
 346                                        int recursion_level);
 347static void btrfsic_print_add_link(const struct btrfsic_state *state,
 348                                   const struct btrfsic_block_link *l);
 349static void btrfsic_print_rem_link(const struct btrfsic_state *state,
 350                                   const struct btrfsic_block_link *l);
 351static char btrfsic_get_block_type(const struct btrfsic_state *state,
 352                                   const struct btrfsic_block *block);
 353static void btrfsic_dump_tree(const struct btrfsic_state *state);
 354static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
 355                                  const struct btrfsic_block *block,
 356                                  int indent_level);
 357static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
 358                struct btrfsic_state *state,
 359                struct btrfsic_block_data_ctx *next_block_ctx,
 360                struct btrfsic_block *next_block,
 361                struct btrfsic_block *from_block,
 362                u64 parent_generation);
 363static struct btrfsic_block *btrfsic_block_lookup_or_add(
 364                struct btrfsic_state *state,
 365                struct btrfsic_block_data_ctx *block_ctx,
 366                const char *additional_string,
 367                int is_metadata,
 368                int is_iodone,
 369                int never_written,
 370                int mirror_num,
 371                int *was_created);
 372static int btrfsic_process_superblock_dev_mirror(
 373                struct btrfsic_state *state,
 374                struct btrfsic_dev_state *dev_state,
 375                struct btrfs_device *device,
 376                int superblock_mirror_num,
 377                struct btrfsic_dev_state **selected_dev_state,
 378                struct btrfs_super_block *selected_super);
 379static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
 380                struct block_device *bdev);
 381static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
 382                                           u64 bytenr,
 383                                           struct btrfsic_dev_state *dev_state,
 384                                           u64 dev_bytenr);
 385
 386static struct mutex btrfsic_mutex;
 387static int btrfsic_is_initialized;
 388static struct btrfsic_dev_state_hashtable btrfsic_dev_state_hashtable;
 389
 390
 391static void btrfsic_block_init(struct btrfsic_block *b)
 392{
 393        b->magic_num = BTRFSIC_BLOCK_MAGIC_NUMBER;
 394        b->dev_state = NULL;
 395        b->dev_bytenr = 0;
 396        b->logical_bytenr = 0;
 397        b->generation = BTRFSIC_GENERATION_UNKNOWN;
 398        b->disk_key.objectid = 0;
 399        b->disk_key.type = 0;
 400        b->disk_key.offset = 0;
 401        b->is_metadata = 0;
 402        b->is_superblock = 0;
 403        b->is_iodone = 0;
 404        b->iodone_w_error = 0;
 405        b->never_written = 0;
 406        b->mirror_num = 0;
 407        b->next_in_same_bio = NULL;
 408        b->orig_bio_bh_private = NULL;
 409        b->orig_bio_bh_end_io.bio = NULL;
 410        INIT_LIST_HEAD(&b->collision_resolving_node);
 411        INIT_LIST_HEAD(&b->all_blocks_node);
 412        INIT_LIST_HEAD(&b->ref_to_list);
 413        INIT_LIST_HEAD(&b->ref_from_list);
 414        b->submit_bio_bh_rw = 0;
 415        b->flush_gen = 0;
 416}
 417
 418static struct btrfsic_block *btrfsic_block_alloc(void)
 419{
 420        struct btrfsic_block *b;
 421
 422        b = kzalloc(sizeof(*b), GFP_NOFS);
 423        if (NULL != b)
 424                btrfsic_block_init(b);
 425
 426        return b;
 427}
 428
 429static void btrfsic_block_free(struct btrfsic_block *b)
 430{
 431        BUG_ON(!(NULL == b || BTRFSIC_BLOCK_MAGIC_NUMBER == b->magic_num));
 432        kfree(b);
 433}
 434
 435static void btrfsic_block_link_init(struct btrfsic_block_link *l)
 436{
 437        l->magic_num = BTRFSIC_BLOCK_LINK_MAGIC_NUMBER;
 438        l->ref_cnt = 1;
 439        INIT_LIST_HEAD(&l->node_ref_to);
 440        INIT_LIST_HEAD(&l->node_ref_from);
 441        INIT_LIST_HEAD(&l->collision_resolving_node);
 442        l->block_ref_to = NULL;
 443        l->block_ref_from = NULL;
 444}
 445
 446static struct btrfsic_block_link *btrfsic_block_link_alloc(void)
 447{
 448        struct btrfsic_block_link *l;
 449
 450        l = kzalloc(sizeof(*l), GFP_NOFS);
 451        if (NULL != l)
 452                btrfsic_block_link_init(l);
 453
 454        return l;
 455}
 456
 457static void btrfsic_block_link_free(struct btrfsic_block_link *l)
 458{
 459        BUG_ON(!(NULL == l || BTRFSIC_BLOCK_LINK_MAGIC_NUMBER == l->magic_num));
 460        kfree(l);
 461}
 462
 463static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds)
 464{
 465        ds->magic_num = BTRFSIC_DEV2STATE_MAGIC_NUMBER;
 466        ds->bdev = NULL;
 467        ds->state = NULL;
 468        ds->name[0] = '\0';
 469        INIT_LIST_HEAD(&ds->collision_resolving_node);
 470        ds->last_flush_gen = 0;
 471        btrfsic_block_init(&ds->dummy_block_for_bio_bh_flush);
 472        ds->dummy_block_for_bio_bh_flush.is_iodone = 1;
 473        ds->dummy_block_for_bio_bh_flush.dev_state = ds;
 474}
 475
 476static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void)
 477{
 478        struct btrfsic_dev_state *ds;
 479
 480        ds = kzalloc(sizeof(*ds), GFP_NOFS);
 481        if (NULL != ds)
 482                btrfsic_dev_state_init(ds);
 483
 484        return ds;
 485}
 486
 487static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds)
 488{
 489        BUG_ON(!(NULL == ds ||
 490                 BTRFSIC_DEV2STATE_MAGIC_NUMBER == ds->magic_num));
 491        kfree(ds);
 492}
 493
 494static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h)
 495{
 496        int i;
 497
 498        for (i = 0; i < BTRFSIC_BLOCK_HASHTABLE_SIZE; i++)
 499                INIT_LIST_HEAD(h->table + i);
 500}
 501
 502static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
 503                                        struct btrfsic_block_hashtable *h)
 504{
 505        const unsigned int hashval =
 506            (((unsigned int)(b->dev_bytenr >> 16)) ^
 507             ((unsigned int)((uintptr_t)b->dev_state->bdev))) &
 508             (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
 509
 510        list_add(&b->collision_resolving_node, h->table + hashval);
 511}
 512
 513static void btrfsic_block_hashtable_remove(struct btrfsic_block *b)
 514{
 515        list_del(&b->collision_resolving_node);
 516}
 517
 518static struct btrfsic_block *btrfsic_block_hashtable_lookup(
 519                struct block_device *bdev,
 520                u64 dev_bytenr,
 521                struct btrfsic_block_hashtable *h)
 522{
 523        const unsigned int hashval =
 524            (((unsigned int)(dev_bytenr >> 16)) ^
 525             ((unsigned int)((uintptr_t)bdev))) &
 526             (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
 527        struct list_head *elem;
 528
 529        list_for_each(elem, h->table + hashval) {
 530                struct btrfsic_block *const b =
 531                    list_entry(elem, struct btrfsic_block,
 532                               collision_resolving_node);
 533
 534                if (b->dev_state->bdev == bdev && b->dev_bytenr == dev_bytenr)
 535                        return b;
 536        }
 537
 538        return NULL;
 539}
 540
 541static void btrfsic_block_link_hashtable_init(
 542                struct btrfsic_block_link_hashtable *h)
 543{
 544        int i;
 545
 546        for (i = 0; i < BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE; i++)
 547                INIT_LIST_HEAD(h->table + i);
 548}
 549
 550static void btrfsic_block_link_hashtable_add(
 551                struct btrfsic_block_link *l,
 552                struct btrfsic_block_link_hashtable *h)
 553{
 554        const unsigned int hashval =
 555            (((unsigned int)(l->block_ref_to->dev_bytenr >> 16)) ^
 556             ((unsigned int)(l->block_ref_from->dev_bytenr >> 16)) ^
 557             ((unsigned int)((uintptr_t)l->block_ref_to->dev_state->bdev)) ^
 558             ((unsigned int)((uintptr_t)l->block_ref_from->dev_state->bdev)))
 559             & (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
 560
 561        BUG_ON(NULL == l->block_ref_to);
 562        BUG_ON(NULL == l->block_ref_from);
 563        list_add(&l->collision_resolving_node, h->table + hashval);
 564}
 565
 566static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l)
 567{
 568        list_del(&l->collision_resolving_node);
 569}
 570
 571static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
 572                struct block_device *bdev_ref_to,
 573                u64 dev_bytenr_ref_to,
 574                struct block_device *bdev_ref_from,
 575                u64 dev_bytenr_ref_from,
 576                struct btrfsic_block_link_hashtable *h)
 577{
 578        const unsigned int hashval =
 579            (((unsigned int)(dev_bytenr_ref_to >> 16)) ^
 580             ((unsigned int)(dev_bytenr_ref_from >> 16)) ^
 581             ((unsigned int)((uintptr_t)bdev_ref_to)) ^
 582             ((unsigned int)((uintptr_t)bdev_ref_from))) &
 583             (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
 584        struct list_head *elem;
 585
 586        list_for_each(elem, h->table + hashval) {
 587                struct btrfsic_block_link *const l =
 588                    list_entry(elem, struct btrfsic_block_link,
 589                               collision_resolving_node);
 590
 591                BUG_ON(NULL == l->block_ref_to);
 592                BUG_ON(NULL == l->block_ref_from);
 593                if (l->block_ref_to->dev_state->bdev == bdev_ref_to &&
 594                    l->block_ref_to->dev_bytenr == dev_bytenr_ref_to &&
 595                    l->block_ref_from->dev_state->bdev == bdev_ref_from &&
 596                    l->block_ref_from->dev_bytenr == dev_bytenr_ref_from)
 597                        return l;
 598        }
 599
 600        return NULL;
 601}
 602
 603static void btrfsic_dev_state_hashtable_init(
 604                struct btrfsic_dev_state_hashtable *h)
 605{
 606        int i;
 607
 608        for (i = 0; i < BTRFSIC_DEV2STATE_HASHTABLE_SIZE; i++)
 609                INIT_LIST_HEAD(h->table + i);
 610}
 611
 612static void btrfsic_dev_state_hashtable_add(
 613                struct btrfsic_dev_state *ds,
 614                struct btrfsic_dev_state_hashtable *h)
 615{
 616        const unsigned int hashval =
 617            (((unsigned int)((uintptr_t)ds->bdev)) &
 618             (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
 619
 620        list_add(&ds->collision_resolving_node, h->table + hashval);
 621}
 622
 623static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds)
 624{
 625        list_del(&ds->collision_resolving_node);
 626}
 627
 628static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
 629                struct block_device *bdev,
 630                struct btrfsic_dev_state_hashtable *h)
 631{
 632        const unsigned int hashval =
 633            (((unsigned int)((uintptr_t)bdev)) &
 634             (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
 635        struct list_head *elem;
 636
 637        list_for_each(elem, h->table + hashval) {
 638                struct btrfsic_dev_state *const ds =
 639                    list_entry(elem, struct btrfsic_dev_state,
 640                               collision_resolving_node);
 641
 642                if (ds->bdev == bdev)
 643                        return ds;
 644        }
 645
 646        return NULL;
 647}
 648
 649static int btrfsic_process_superblock(struct btrfsic_state *state,
 650                                      struct btrfs_fs_devices *fs_devices)
 651{
 652        int ret = 0;
 653        struct btrfs_super_block *selected_super;
 654        struct list_head *dev_head = &fs_devices->devices;
 655        struct btrfs_device *device;
 656        struct btrfsic_dev_state *selected_dev_state = NULL;
 657        int pass;
 658
 659        BUG_ON(NULL == state);
 660        selected_super = kzalloc(sizeof(*selected_super), GFP_NOFS);
 661        if (NULL == selected_super) {
 662                printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
 663                return -1;
 664        }
 665
 666        list_for_each_entry(device, dev_head, dev_list) {
 667                int i;
 668                struct btrfsic_dev_state *dev_state;
 669
 670                if (!device->bdev || !device->name)
 671                        continue;
 672
 673                dev_state = btrfsic_dev_state_lookup(device->bdev);
 674                BUG_ON(NULL == dev_state);
 675                for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 676                        ret = btrfsic_process_superblock_dev_mirror(
 677                                        state, dev_state, device, i,
 678                                        &selected_dev_state, selected_super);
 679                        if (0 != ret && 0 == i) {
 680                                kfree(selected_super);
 681                                return ret;
 682                        }
 683                }
 684        }
 685
 686        if (NULL == state->latest_superblock) {
 687                printk(KERN_INFO "btrfsic: no superblock found!\n");
 688                kfree(selected_super);
 689                return -1;
 690        }
 691
 692        state->csum_size = btrfs_super_csum_size(selected_super);
 693
 694        for (pass = 0; pass < 3; pass++) {
 695                int num_copies;
 696                int mirror_num;
 697                u64 next_bytenr;
 698
 699                switch (pass) {
 700                case 0:
 701                        next_bytenr = btrfs_super_root(selected_super);
 702                        if (state->print_mask &
 703                            BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 704                                printk(KERN_INFO "root@%llu\n",
 705                                       (unsigned long long)next_bytenr);
 706                        break;
 707                case 1:
 708                        next_bytenr = btrfs_super_chunk_root(selected_super);
 709                        if (state->print_mask &
 710                            BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 711                                printk(KERN_INFO "chunk@%llu\n",
 712                                       (unsigned long long)next_bytenr);
 713                        break;
 714                case 2:
 715                        next_bytenr = btrfs_super_log_root(selected_super);
 716                        if (0 == next_bytenr)
 717                                continue;
 718                        if (state->print_mask &
 719                            BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 720                                printk(KERN_INFO "log@%llu\n",
 721                                       (unsigned long long)next_bytenr);
 722                        break;
 723                }
 724
 725                num_copies =
 726                    btrfs_num_copies(&state->root->fs_info->mapping_tree,
 727                                     next_bytenr, state->metablock_size);
 728                if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 729                        printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
 730                               (unsigned long long)next_bytenr, num_copies);
 731
 732                for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 733                        struct btrfsic_block *next_block;
 734                        struct btrfsic_block_data_ctx tmp_next_block_ctx;
 735                        struct btrfsic_block_link *l;
 736
 737                        ret = btrfsic_map_block(state, next_bytenr,
 738                                                state->metablock_size,
 739                                                &tmp_next_block_ctx,
 740                                                mirror_num);
 741                        if (ret) {
 742                                printk(KERN_INFO "btrfsic:"
 743                                       " btrfsic_map_block(root @%llu,"
 744                                       " mirror %d) failed!\n",
 745                                       (unsigned long long)next_bytenr,
 746                                       mirror_num);
 747                                kfree(selected_super);
 748                                return -1;
 749                        }
 750
 751                        next_block = btrfsic_block_hashtable_lookup(
 752                                        tmp_next_block_ctx.dev->bdev,
 753                                        tmp_next_block_ctx.dev_bytenr,
 754                                        &state->block_hashtable);
 755                        BUG_ON(NULL == next_block);
 756
 757                        l = btrfsic_block_link_hashtable_lookup(
 758                                        tmp_next_block_ctx.dev->bdev,
 759                                        tmp_next_block_ctx.dev_bytenr,
 760                                        state->latest_superblock->dev_state->
 761                                        bdev,
 762                                        state->latest_superblock->dev_bytenr,
 763                                        &state->block_link_hashtable);
 764                        BUG_ON(NULL == l);
 765
 766                        ret = btrfsic_read_block(state, &tmp_next_block_ctx);
 767                        if (ret < (int)PAGE_CACHE_SIZE) {
 768                                printk(KERN_INFO
 769                                       "btrfsic: read @logical %llu failed!\n",
 770                                       (unsigned long long)
 771                                       tmp_next_block_ctx.start);
 772                                btrfsic_release_block_ctx(&tmp_next_block_ctx);
 773                                kfree(selected_super);
 774                                return -1;
 775                        }
 776
 777                        ret = btrfsic_process_metablock(state,
 778                                                        next_block,
 779                                                        &tmp_next_block_ctx,
 780                                                        BTRFS_MAX_LEVEL + 3, 1);
 781                        btrfsic_release_block_ctx(&tmp_next_block_ctx);
 782                }
 783        }
 784
 785        kfree(selected_super);
 786        return ret;
 787}
 788
 789static int btrfsic_process_superblock_dev_mirror(
 790                struct btrfsic_state *state,
 791                struct btrfsic_dev_state *dev_state,
 792                struct btrfs_device *device,
 793                int superblock_mirror_num,
 794                struct btrfsic_dev_state **selected_dev_state,
 795                struct btrfs_super_block *selected_super)
 796{
 797        struct btrfs_super_block *super_tmp;
 798        u64 dev_bytenr;
 799        struct buffer_head *bh;
 800        struct btrfsic_block *superblock_tmp;
 801        int pass;
 802        struct block_device *const superblock_bdev = device->bdev;
 803
 804        /* super block bytenr is always the unmapped device bytenr */
 805        dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
 806        if (dev_bytenr + BTRFS_SUPER_INFO_SIZE > device->total_bytes)
 807                return -1;
 808        bh = __bread(superblock_bdev, dev_bytenr / 4096,
 809                     BTRFS_SUPER_INFO_SIZE);
 810        if (NULL == bh)
 811                return -1;
 812        super_tmp = (struct btrfs_super_block *)
 813            (bh->b_data + (dev_bytenr & 4095));
 814
 815        if (btrfs_super_bytenr(super_tmp) != dev_bytenr ||
 816            strncmp((char *)(&(super_tmp->magic)), BTRFS_MAGIC,
 817                    sizeof(super_tmp->magic)) ||
 818            memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE) ||
 819            btrfs_super_nodesize(super_tmp) != state->metablock_size ||
 820            btrfs_super_leafsize(super_tmp) != state->metablock_size ||
 821            btrfs_super_sectorsize(super_tmp) != state->datablock_size) {
 822                brelse(bh);
 823                return 0;
 824        }
 825
 826        superblock_tmp =
 827            btrfsic_block_hashtable_lookup(superblock_bdev,
 828                                           dev_bytenr,
 829                                           &state->block_hashtable);
 830        if (NULL == superblock_tmp) {
 831                superblock_tmp = btrfsic_block_alloc();
 832                if (NULL == superblock_tmp) {
 833                        printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
 834                        brelse(bh);
 835                        return -1;
 836                }
 837                /* for superblock, only the dev_bytenr makes sense */
 838                superblock_tmp->dev_bytenr = dev_bytenr;
 839                superblock_tmp->dev_state = dev_state;
 840                superblock_tmp->logical_bytenr = dev_bytenr;
 841                superblock_tmp->generation = btrfs_super_generation(super_tmp);
 842                superblock_tmp->is_metadata = 1;
 843                superblock_tmp->is_superblock = 1;
 844                superblock_tmp->is_iodone = 1;
 845                superblock_tmp->never_written = 0;
 846                superblock_tmp->mirror_num = 1 + superblock_mirror_num;
 847                if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
 848                        printk_in_rcu(KERN_INFO "New initial S-block (bdev %p, %s)"
 849                                     " @%llu (%s/%llu/%d)\n",
 850                                     superblock_bdev,
 851                                     rcu_str_deref(device->name),
 852                                     (unsigned long long)dev_bytenr,
 853                                     dev_state->name,
 854                                     (unsigned long long)dev_bytenr,
 855                                     superblock_mirror_num);
 856                list_add(&superblock_tmp->all_blocks_node,
 857                         &state->all_blocks_list);
 858                btrfsic_block_hashtable_add(superblock_tmp,
 859                                            &state->block_hashtable);
 860        }
 861
 862        /* select the one with the highest generation field */
 863        if (btrfs_super_generation(super_tmp) >
 864            state->max_superblock_generation ||
 865            0 == state->max_superblock_generation) {
 866                memcpy(selected_super, super_tmp, sizeof(*selected_super));
 867                *selected_dev_state = dev_state;
 868                state->max_superblock_generation =
 869                    btrfs_super_generation(super_tmp);
 870                state->latest_superblock = superblock_tmp;
 871        }
 872
 873        for (pass = 0; pass < 3; pass++) {
 874                u64 next_bytenr;
 875                int num_copies;
 876                int mirror_num;
 877                const char *additional_string = NULL;
 878                struct btrfs_disk_key tmp_disk_key;
 879
 880                tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
 881                tmp_disk_key.offset = 0;
 882                switch (pass) {
 883                case 0:
 884                        tmp_disk_key.objectid =
 885                            cpu_to_le64(BTRFS_ROOT_TREE_OBJECTID);
 886                        additional_string = "initial root ";
 887                        next_bytenr = btrfs_super_root(super_tmp);
 888                        break;
 889                case 1:
 890                        tmp_disk_key.objectid =
 891                            cpu_to_le64(BTRFS_CHUNK_TREE_OBJECTID);
 892                        additional_string = "initial chunk ";
 893                        next_bytenr = btrfs_super_chunk_root(super_tmp);
 894                        break;
 895                case 2:
 896                        tmp_disk_key.objectid =
 897                            cpu_to_le64(BTRFS_TREE_LOG_OBJECTID);
 898                        additional_string = "initial log ";
 899                        next_bytenr = btrfs_super_log_root(super_tmp);
 900                        if (0 == next_bytenr)
 901                                continue;
 902                        break;
 903                }
 904
 905                num_copies =
 906                    btrfs_num_copies(&state->root->fs_info->mapping_tree,
 907                                     next_bytenr, state->metablock_size);
 908                if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 909                        printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
 910                               (unsigned long long)next_bytenr, num_copies);
 911                for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 912                        struct btrfsic_block *next_block;
 913                        struct btrfsic_block_data_ctx tmp_next_block_ctx;
 914                        struct btrfsic_block_link *l;
 915
 916                        if (btrfsic_map_block(state, next_bytenr,
 917                                              state->metablock_size,
 918                                              &tmp_next_block_ctx,
 919                                              mirror_num)) {
 920                                printk(KERN_INFO "btrfsic: btrfsic_map_block("
 921                                       "bytenr @%llu, mirror %d) failed!\n",
 922                                       (unsigned long long)next_bytenr,
 923                                       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 = le32_to_cpu(leafhdr->header.nritems);
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                                       (unsigned long long)
1014                                       sf->block_ctx->start,
1015                                       sf->nr,
1016                                       (unsigned long long)
1017                                       le64_to_cpu(leafhdr->header.generation),
1018                                       (unsigned long long)
1019                                       le64_to_cpu(leafhdr->header.owner));
1020                }
1021
1022continue_with_current_leaf_stack_frame:
1023                if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1024                        sf->i++;
1025                        sf->num_copies = 0;
1026                }
1027
1028                if (sf->i < sf->nr) {
1029                        struct btrfs_item disk_item;
1030                        u32 disk_item_offset =
1031                                (uintptr_t)(leafhdr->items + sf->i) -
1032                                (uintptr_t)leafhdr;
1033                        struct btrfs_disk_key *disk_key;
1034                        u8 type;
1035                        u32 item_offset;
1036                        u32 item_size;
1037
1038                        if (disk_item_offset + sizeof(struct btrfs_item) >
1039                            sf->block_ctx->len) {
1040leaf_item_out_of_bounce_error:
1041                                printk(KERN_INFO
1042                                       "btrfsic: leaf item out of bounce at logical %llu, dev %s\n",
1043                                       sf->block_ctx->start,
1044                                       sf->block_ctx->dev->name);
1045                                goto one_stack_frame_backwards;
1046                        }
1047                        btrfsic_read_from_block_data(sf->block_ctx,
1048                                                     &disk_item,
1049                                                     disk_item_offset,
1050                                                     sizeof(struct btrfs_item));
1051                        item_offset = le32_to_cpu(disk_item.offset);
1052                        item_size = le32_to_cpu(disk_item.size);
1053                        disk_key = &disk_item.key;
1054                        type = disk_key->type;
1055
1056                        if (BTRFS_ROOT_ITEM_KEY == type) {
1057                                struct btrfs_root_item root_item;
1058                                u32 root_item_offset;
1059                                u64 next_bytenr;
1060
1061                                root_item_offset = item_offset +
1062                                        offsetof(struct btrfs_leaf, items);
1063                                if (root_item_offset + item_size >
1064                                    sf->block_ctx->len)
1065                                        goto leaf_item_out_of_bounce_error;
1066                                btrfsic_read_from_block_data(
1067                                        sf->block_ctx, &root_item,
1068                                        root_item_offset,
1069                                        item_size);
1070                                next_bytenr = le64_to_cpu(root_item.bytenr);
1071
1072                                sf->error =
1073                                    btrfsic_create_link_to_next_block(
1074                                                state,
1075                                                sf->block,
1076                                                sf->block_ctx,
1077                                                next_bytenr,
1078                                                sf->limit_nesting,
1079                                                &sf->next_block_ctx,
1080                                                &sf->next_block,
1081                                                force_iodone_flag,
1082                                                &sf->num_copies,
1083                                                &sf->mirror_num,
1084                                                disk_key,
1085                                                le64_to_cpu(root_item.
1086                                                generation));
1087                                if (sf->error)
1088                                        goto one_stack_frame_backwards;
1089
1090                                if (NULL != sf->next_block) {
1091                                        struct btrfs_header *const next_hdr =
1092                                            (struct btrfs_header *)
1093                                            sf->next_block_ctx.datav[0];
1094
1095                                        next_stack =
1096                                            btrfsic_stack_frame_alloc();
1097                                        if (NULL == next_stack) {
1098                                                btrfsic_release_block_ctx(
1099                                                                &sf->
1100                                                                next_block_ctx);
1101                                                goto one_stack_frame_backwards;
1102                                        }
1103
1104                                        next_stack->i = -1;
1105                                        next_stack->block = sf->next_block;
1106                                        next_stack->block_ctx =
1107                                            &sf->next_block_ctx;
1108                                        next_stack->next_block = NULL;
1109                                        next_stack->hdr = next_hdr;
1110                                        next_stack->limit_nesting =
1111                                            sf->limit_nesting - 1;
1112                                        next_stack->prev = sf;
1113                                        sf = next_stack;
1114                                        goto continue_with_new_stack_frame;
1115                                }
1116                        } else if (BTRFS_EXTENT_DATA_KEY == type &&
1117                                   state->include_extent_data) {
1118                                sf->error = btrfsic_handle_extent_data(
1119                                                state,
1120                                                sf->block,
1121                                                sf->block_ctx,
1122                                                item_offset,
1123                                                force_iodone_flag);
1124                                if (sf->error)
1125                                        goto one_stack_frame_backwards;
1126                        }
1127
1128                        goto continue_with_current_leaf_stack_frame;
1129                }
1130        } else {
1131                struct btrfs_node *const nodehdr = (struct btrfs_node *)sf->hdr;
1132
1133                if (-1 == sf->i) {
1134                        sf->nr = le32_to_cpu(nodehdr->header.nritems);
1135
1136                        if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1137                                printk(KERN_INFO "node %llu level %d items %d"
1138                                       " generation %llu owner %llu\n",
1139                                       (unsigned long long)
1140                                       sf->block_ctx->start,
1141                                       nodehdr->header.level, sf->nr,
1142                                       (unsigned long long)
1143                                       le64_to_cpu(nodehdr->header.generation),
1144                                       (unsigned long long)
1145                                       le64_to_cpu(nodehdr->header.owner));
1146                }
1147
1148continue_with_current_node_stack_frame:
1149                if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1150                        sf->i++;
1151                        sf->num_copies = 0;
1152                }
1153
1154                if (sf->i < sf->nr) {
1155                        struct btrfs_key_ptr key_ptr;
1156                        u32 key_ptr_offset;
1157                        u64 next_bytenr;
1158
1159                        key_ptr_offset = (uintptr_t)(nodehdr->ptrs + sf->i) -
1160                                          (uintptr_t)nodehdr;
1161                        if (key_ptr_offset + sizeof(struct btrfs_key_ptr) >
1162                            sf->block_ctx->len) {
1163                                printk(KERN_INFO
1164                                       "btrfsic: node item out of bounce at logical %llu, dev %s\n",
1165                                       sf->block_ctx->start,
1166                                       sf->block_ctx->dev->name);
1167                                goto one_stack_frame_backwards;
1168                        }
1169                        btrfsic_read_from_block_data(
1170                                sf->block_ctx, &key_ptr, key_ptr_offset,
1171                                sizeof(struct btrfs_key_ptr));
1172                        next_bytenr = le64_to_cpu(key_ptr.blockptr);
1173
1174                        sf->error = btrfsic_create_link_to_next_block(
1175                                        state,
1176                                        sf->block,
1177                                        sf->block_ctx,
1178                                        next_bytenr,
1179                                        sf->limit_nesting,
1180                                        &sf->next_block_ctx,
1181                                        &sf->next_block,
1182                                        force_iodone_flag,
1183                                        &sf->num_copies,
1184                                        &sf->mirror_num,
1185                                        &key_ptr.key,
1186                                        le64_to_cpu(key_ptr.generation));
1187                        if (sf->error)
1188                                goto one_stack_frame_backwards;
1189
1190                        if (NULL != sf->next_block) {
1191                                struct btrfs_header *const next_hdr =
1192                                    (struct btrfs_header *)
1193                                    sf->next_block_ctx.datav[0];
1194
1195                                next_stack = btrfsic_stack_frame_alloc();
1196                                if (NULL == next_stack)
1197                                        goto one_stack_frame_backwards;
1198
1199                                next_stack->i = -1;
1200                                next_stack->block = sf->next_block;
1201                                next_stack->block_ctx = &sf->next_block_ctx;
1202                                next_stack->next_block = NULL;
1203                                next_stack->hdr = next_hdr;
1204                                next_stack->limit_nesting =
1205                                    sf->limit_nesting - 1;
1206                                next_stack->prev = sf;
1207                                sf = next_stack;
1208                                goto continue_with_new_stack_frame;
1209                        }
1210
1211                        goto continue_with_current_node_stack_frame;
1212                }
1213        }
1214
1215one_stack_frame_backwards:
1216        if (NULL != sf->prev) {
1217                struct btrfsic_stack_frame *const prev = sf->prev;
1218
1219                /* the one for the initial block is freed in the caller */
1220                btrfsic_release_block_ctx(sf->block_ctx);
1221
1222                if (sf->error) {
1223                        prev->error = sf->error;
1224                        btrfsic_stack_frame_free(sf);
1225                        sf = prev;
1226                        goto one_stack_frame_backwards;
1227                }
1228
1229                btrfsic_stack_frame_free(sf);
1230                sf = prev;
1231                goto continue_with_new_stack_frame;
1232        } else {
1233                BUG_ON(&initial_stack_frame != sf);
1234        }
1235
1236        return sf->error;
1237}
1238
1239static void btrfsic_read_from_block_data(
1240        struct btrfsic_block_data_ctx *block_ctx,
1241        void *dstv, u32 offset, size_t len)
1242{
1243        size_t cur;
1244        size_t offset_in_page;
1245        char *kaddr;
1246        char *dst = (char *)dstv;
1247        size_t start_offset = block_ctx->start & ((u64)PAGE_CACHE_SIZE - 1);
1248        unsigned long i = (start_offset + offset) >> PAGE_CACHE_SHIFT;
1249
1250        WARN_ON(offset + len > block_ctx->len);
1251        offset_in_page = (start_offset + offset) &
1252                         ((unsigned long)PAGE_CACHE_SIZE - 1);
1253
1254        while (len > 0) {
1255                cur = min(len, ((size_t)PAGE_CACHE_SIZE - offset_in_page));
1256                BUG_ON(i >= (block_ctx->len + PAGE_CACHE_SIZE - 1) >>
1257                            PAGE_CACHE_SHIFT);
1258                kaddr = block_ctx->datav[i];
1259                memcpy(dst, kaddr + offset_in_page, cur);
1260
1261                dst += cur;
1262                len -= cur;
1263                offset_in_page = 0;
1264                i++;
1265        }
1266}
1267
1268static int btrfsic_create_link_to_next_block(
1269                struct btrfsic_state *state,
1270                struct btrfsic_block *block,
1271                struct btrfsic_block_data_ctx *block_ctx,
1272                u64 next_bytenr,
1273                int limit_nesting,
1274                struct btrfsic_block_data_ctx *next_block_ctx,
1275                struct btrfsic_block **next_blockp,
1276                int force_iodone_flag,
1277                int *num_copiesp, int *mirror_nump,
1278                struct btrfs_disk_key *disk_key,
1279                u64 parent_generation)
1280{
1281        struct btrfsic_block *next_block = NULL;
1282        int ret;
1283        struct btrfsic_block_link *l;
1284        int did_alloc_block_link;
1285        int block_was_created;
1286
1287        *next_blockp = NULL;
1288        if (0 == *num_copiesp) {
1289                *num_copiesp =
1290                    btrfs_num_copies(&state->root->fs_info->mapping_tree,
1291                                     next_bytenr, state->metablock_size);
1292                if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1293                        printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1294                               (unsigned long long)next_bytenr, *num_copiesp);
1295                *mirror_nump = 1;
1296        }
1297
1298        if (*mirror_nump > *num_copiesp)
1299                return 0;
1300
1301        if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1302                printk(KERN_INFO
1303                       "btrfsic_create_link_to_next_block(mirror_num=%d)\n",
1304                       *mirror_nump);
1305        ret = btrfsic_map_block(state, next_bytenr,
1306                                state->metablock_size,
1307                                next_block_ctx, *mirror_nump);
1308        if (ret) {
1309                printk(KERN_INFO
1310                       "btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1311                       (unsigned long long)next_bytenr, *mirror_nump);
1312                btrfsic_release_block_ctx(next_block_ctx);
1313                *next_blockp = NULL;
1314                return -1;
1315        }
1316
1317        next_block = btrfsic_block_lookup_or_add(state,
1318                                                 next_block_ctx, "referenced ",
1319                                                 1, force_iodone_flag,
1320                                                 !force_iodone_flag,
1321                                                 *mirror_nump,
1322                                                 &block_was_created);
1323        if (NULL == next_block) {
1324                btrfsic_release_block_ctx(next_block_ctx);
1325                *next_blockp = NULL;
1326                return -1;
1327        }
1328        if (block_was_created) {
1329                l = NULL;
1330                next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
1331        } else {
1332                if (next_block->logical_bytenr != next_bytenr &&
1333                    !(!next_block->is_metadata &&
1334                      0 == next_block->logical_bytenr)) {
1335                        printk(KERN_INFO
1336                               "Referenced block @%llu (%s/%llu/%d)"
1337                               " found in hash table, %c,"
1338                               " bytenr mismatch (!= stored %llu).\n",
1339                               (unsigned long long)next_bytenr,
1340                               next_block_ctx->dev->name,
1341                               (unsigned long long)next_block_ctx->dev_bytenr,
1342                               *mirror_nump,
1343                               btrfsic_get_block_type(state, next_block),
1344                               (unsigned long long)next_block->logical_bytenr);
1345                } else if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1346                        printk(KERN_INFO
1347                               "Referenced block @%llu (%s/%llu/%d)"
1348                               " found in hash table, %c.\n",
1349                               (unsigned long long)next_bytenr,
1350                               next_block_ctx->dev->name,
1351                               (unsigned long long)next_block_ctx->dev_bytenr,
1352                               *mirror_nump,
1353                               btrfsic_get_block_type(state, next_block));
1354                next_block->logical_bytenr = next_bytenr;
1355
1356                next_block->mirror_num = *mirror_nump;
1357                l = btrfsic_block_link_hashtable_lookup(
1358                                next_block_ctx->dev->bdev,
1359                                next_block_ctx->dev_bytenr,
1360                                block_ctx->dev->bdev,
1361                                block_ctx->dev_bytenr,
1362                                &state->block_link_hashtable);
1363        }
1364
1365        next_block->disk_key = *disk_key;
1366        if (NULL == l) {
1367                l = btrfsic_block_link_alloc();
1368                if (NULL == l) {
1369                        printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
1370                        btrfsic_release_block_ctx(next_block_ctx);
1371                        *next_blockp = NULL;
1372                        return -1;
1373                }
1374
1375                did_alloc_block_link = 1;
1376                l->block_ref_to = next_block;
1377                l->block_ref_from = block;
1378                l->ref_cnt = 1;
1379                l->parent_generation = parent_generation;
1380
1381                if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1382                        btrfsic_print_add_link(state, l);
1383
1384                list_add(&l->node_ref_to, &block->ref_to_list);
1385                list_add(&l->node_ref_from, &next_block->ref_from_list);
1386
1387                btrfsic_block_link_hashtable_add(l,
1388                                                 &state->block_link_hashtable);
1389        } else {
1390                did_alloc_block_link = 0;
1391                if (0 == limit_nesting) {
1392                        l->ref_cnt++;
1393                        l->parent_generation = parent_generation;
1394                        if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1395                                btrfsic_print_add_link(state, l);
1396                }
1397        }
1398
1399        if (limit_nesting > 0 && did_alloc_block_link) {
1400                ret = btrfsic_read_block(state, next_block_ctx);
1401                if (ret < (int)next_block_ctx->len) {
1402                        printk(KERN_INFO
1403                               "btrfsic: read block @logical %llu failed!\n",
1404                               (unsigned long long)next_bytenr);
1405                        btrfsic_release_block_ctx(next_block_ctx);
1406                        *next_blockp = NULL;
1407                        return -1;
1408                }
1409
1410                *next_blockp = next_block;
1411        } else {
1412                *next_blockp = NULL;
1413        }
1414        (*mirror_nump)++;
1415
1416        return 0;
1417}
1418
1419static int btrfsic_handle_extent_data(
1420                struct btrfsic_state *state,
1421                struct btrfsic_block *block,
1422                struct btrfsic_block_data_ctx *block_ctx,
1423                u32 item_offset, int force_iodone_flag)
1424{
1425        int ret;
1426        struct btrfs_file_extent_item file_extent_item;
1427        u64 file_extent_item_offset;
1428        u64 next_bytenr;
1429        u64 num_bytes;
1430        u64 generation;
1431        struct btrfsic_block_link *l;
1432
1433        file_extent_item_offset = offsetof(struct btrfs_leaf, items) +
1434                                  item_offset;
1435        if (file_extent_item_offset +
1436            offsetof(struct btrfs_file_extent_item, disk_num_bytes) >
1437            block_ctx->len) {
1438                printk(KERN_INFO
1439                       "btrfsic: file item out of bounce at logical %llu, dev %s\n",
1440                       block_ctx->start, block_ctx->dev->name);
1441                return -1;
1442        }
1443
1444        btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1445                file_extent_item_offset,
1446                offsetof(struct btrfs_file_extent_item, disk_num_bytes));
1447        if (BTRFS_FILE_EXTENT_REG != file_extent_item.type ||
1448            ((u64)0) == le64_to_cpu(file_extent_item.disk_bytenr)) {
1449                if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1450                        printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu\n",
1451                               file_extent_item.type,
1452                               (unsigned long long)
1453                               le64_to_cpu(file_extent_item.disk_bytenr));
1454                return 0;
1455        }
1456
1457        if (file_extent_item_offset + sizeof(struct btrfs_file_extent_item) >
1458            block_ctx->len) {
1459                printk(KERN_INFO
1460                       "btrfsic: file item out of bounce at logical %llu, dev %s\n",
1461                       block_ctx->start, block_ctx->dev->name);
1462                return -1;
1463        }
1464        btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1465                                     file_extent_item_offset,
1466                                     sizeof(struct btrfs_file_extent_item));
1467        next_bytenr = le64_to_cpu(file_extent_item.disk_bytenr) +
1468                      le64_to_cpu(file_extent_item.offset);
1469        generation = le64_to_cpu(file_extent_item.generation);
1470        num_bytes = le64_to_cpu(file_extent_item.num_bytes);
1471        generation = le64_to_cpu(file_extent_item.generation);
1472
1473        if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1474                printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu,"
1475                       " offset = %llu, num_bytes = %llu\n",
1476                       file_extent_item.type,
1477                       (unsigned long long)
1478                       le64_to_cpu(file_extent_item.disk_bytenr),
1479                       (unsigned long long)le64_to_cpu(file_extent_item.offset),
1480                       (unsigned long long)num_bytes);
1481        while (num_bytes > 0) {
1482                u32 chunk_len;
1483                int num_copies;
1484                int mirror_num;
1485
1486                if (num_bytes > state->datablock_size)
1487                        chunk_len = state->datablock_size;
1488                else
1489                        chunk_len = num_bytes;
1490
1491                num_copies =
1492                    btrfs_num_copies(&state->root->fs_info->mapping_tree,
1493                                     next_bytenr, state->datablock_size);
1494                if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1495                        printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1496                               (unsigned long long)next_bytenr, num_copies);
1497                for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
1498                        struct btrfsic_block_data_ctx next_block_ctx;
1499                        struct btrfsic_block *next_block;
1500                        int block_was_created;
1501
1502                        if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1503                                printk(KERN_INFO "btrfsic_handle_extent_data("
1504                                       "mirror_num=%d)\n", mirror_num);
1505                        if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1506                                printk(KERN_INFO
1507                                       "\tdisk_bytenr = %llu, num_bytes %u\n",
1508                                       (unsigned long long)next_bytenr,
1509                                       chunk_len);
1510                        ret = btrfsic_map_block(state, next_bytenr,
1511                                                chunk_len, &next_block_ctx,
1512                                                mirror_num);
1513                        if (ret) {
1514                                printk(KERN_INFO
1515                                       "btrfsic: btrfsic_map_block(@%llu,"
1516                                       " mirror=%d) failed!\n",
1517                                       (unsigned long long)next_bytenr,
1518                                       mirror_num);
1519                                return -1;
1520                        }
1521
1522                        next_block = btrfsic_block_lookup_or_add(
1523                                        state,
1524                                        &next_block_ctx,
1525                                        "referenced ",
1526                                        0,
1527                                        force_iodone_flag,
1528                                        !force_iodone_flag,
1529                                        mirror_num,
1530                                        &block_was_created);
1531                        if (NULL == next_block) {
1532                                printk(KERN_INFO
1533                                       "btrfsic: error, kmalloc failed!\n");
1534                                btrfsic_release_block_ctx(&next_block_ctx);
1535                                return -1;
1536                        }
1537                        if (!block_was_created) {
1538                                if (next_block->logical_bytenr != next_bytenr &&
1539                                    !(!next_block->is_metadata &&
1540                                      0 == next_block->logical_bytenr)) {
1541                                        printk(KERN_INFO
1542                                               "Referenced block"
1543                                               " @%llu (%s/%llu/%d)"
1544                                               " found in hash table, D,"
1545                                               " bytenr mismatch"
1546                                               " (!= stored %llu).\n",
1547                                               (unsigned long long)next_bytenr,
1548                                               next_block_ctx.dev->name,
1549                                               (unsigned long long)
1550                                               next_block_ctx.dev_bytenr,
1551                                               mirror_num,
1552                                               (unsigned long long)
1553                                               next_block->logical_bytenr);
1554                                }
1555                                next_block->logical_bytenr = next_bytenr;
1556                                next_block->mirror_num = mirror_num;
1557                        }
1558
1559                        l = btrfsic_block_link_lookup_or_add(state,
1560                                                             &next_block_ctx,
1561                                                             next_block, block,
1562                                                             generation);
1563                        btrfsic_release_block_ctx(&next_block_ctx);
1564                        if (NULL == l)
1565                                return -1;
1566                }
1567
1568                next_bytenr += chunk_len;
1569                num_bytes -= chunk_len;
1570        }
1571
1572        return 0;
1573}
1574
1575static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
1576                             struct btrfsic_block_data_ctx *block_ctx_out,
1577                             int mirror_num)
1578{
1579        int ret;
1580        u64 length;
1581        struct btrfs_bio *multi = NULL;
1582        struct btrfs_device *device;
1583
1584        length = len;
1585        ret = btrfs_map_block(&state->root->fs_info->mapping_tree, READ,
1586                              bytenr, &length, &multi, mirror_num);
1587
1588        device = multi->stripes[0].dev;
1589        block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev);
1590        block_ctx_out->dev_bytenr = multi->stripes[0].physical;
1591        block_ctx_out->start = bytenr;
1592        block_ctx_out->len = len;
1593        block_ctx_out->datav = NULL;
1594        block_ctx_out->pagev = NULL;
1595        block_ctx_out->mem_to_free = NULL;
1596
1597        if (0 == ret)
1598                kfree(multi);
1599        if (NULL == block_ctx_out->dev) {
1600                ret = -ENXIO;
1601                printk(KERN_INFO "btrfsic: error, cannot lookup dev (#1)!\n");
1602        }
1603
1604        return ret;
1605}
1606
1607static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
1608                                  u32 len, struct block_device *bdev,
1609                                  struct btrfsic_block_data_ctx *block_ctx_out)
1610{
1611        block_ctx_out->dev = btrfsic_dev_state_lookup(bdev);
1612        block_ctx_out->dev_bytenr = bytenr;
1613        block_ctx_out->start = bytenr;
1614        block_ctx_out->len = len;
1615        block_ctx_out->datav = NULL;
1616        block_ctx_out->pagev = NULL;
1617        block_ctx_out->mem_to_free = NULL;
1618        if (NULL != block_ctx_out->dev) {
1619                return 0;
1620        } else {
1621                printk(KERN_INFO "btrfsic: error, cannot lookup dev (#2)!\n");
1622                return -ENXIO;
1623        }
1624}
1625
1626static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
1627{
1628        if (block_ctx->mem_to_free) {
1629                unsigned int num_pages;
1630
1631                BUG_ON(!block_ctx->datav);
1632                BUG_ON(!block_ctx->pagev);
1633                num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
1634                            PAGE_CACHE_SHIFT;
1635                while (num_pages > 0) {
1636                        num_pages--;
1637                        if (block_ctx->datav[num_pages]) {
1638                                kunmap(block_ctx->pagev[num_pages]);
1639                                block_ctx->datav[num_pages] = NULL;
1640                        }
1641                        if (block_ctx->pagev[num_pages]) {
1642                                __free_page(block_ctx->pagev[num_pages]);
1643                                block_ctx->pagev[num_pages] = NULL;
1644                        }
1645                }
1646
1647                kfree(block_ctx->mem_to_free);
1648                block_ctx->mem_to_free = NULL;
1649                block_ctx->pagev = NULL;
1650                block_ctx->datav = NULL;
1651        }
1652}
1653
1654static int btrfsic_read_block(struct btrfsic_state *state,
1655                              struct btrfsic_block_data_ctx *block_ctx)
1656{
1657        unsigned int num_pages;
1658        unsigned int i;
1659        u64 dev_bytenr;
1660        int ret;
1661
1662        BUG_ON(block_ctx->datav);
1663        BUG_ON(block_ctx->pagev);
1664        BUG_ON(block_ctx->mem_to_free);
1665        if (block_ctx->dev_bytenr & ((u64)PAGE_CACHE_SIZE - 1)) {
1666                printk(KERN_INFO
1667                       "btrfsic: read_block() with unaligned bytenr %llu\n",
1668                       (unsigned long long)block_ctx->dev_bytenr);
1669                return -1;
1670        }
1671
1672        num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
1673                    PAGE_CACHE_SHIFT;
1674        block_ctx->mem_to_free = kzalloc((sizeof(*block_ctx->datav) +
1675                                          sizeof(*block_ctx->pagev)) *
1676                                         num_pages, GFP_NOFS);
1677        if (!block_ctx->mem_to_free)
1678                return -1;
1679        block_ctx->datav = block_ctx->mem_to_free;
1680        block_ctx->pagev = (struct page **)(block_ctx->datav + num_pages);
1681        for (i = 0; i < num_pages; i++) {
1682                block_ctx->pagev[i] = alloc_page(GFP_NOFS);
1683                if (!block_ctx->pagev[i])
1684                        return -1;
1685        }
1686
1687        dev_bytenr = block_ctx->dev_bytenr;
1688        for (i = 0; i < num_pages;) {
1689                struct bio *bio;
1690                unsigned int j;
1691                DECLARE_COMPLETION_ONSTACK(complete);
1692
1693                bio = bio_alloc(GFP_NOFS, num_pages - i);
1694                if (!bio) {
1695                        printk(KERN_INFO
1696                               "btrfsic: bio_alloc() for %u pages failed!\n",
1697                               num_pages - i);
1698                        return -1;
1699                }
1700                bio->bi_bdev = block_ctx->dev->bdev;
1701                bio->bi_sector = dev_bytenr >> 9;
1702                bio->bi_end_io = btrfsic_complete_bio_end_io;
1703                bio->bi_private = &complete;
1704
1705                for (j = i; j < num_pages; j++) {
1706                        ret = bio_add_page(bio, block_ctx->pagev[j],
1707                                           PAGE_CACHE_SIZE, 0);
1708                        if (PAGE_CACHE_SIZE != ret)
1709                                break;
1710                }
1711                if (j == i) {
1712                        printk(KERN_INFO
1713                               "btrfsic: error, failed to add a single page!\n");
1714                        return -1;
1715                }
1716                submit_bio(READ, bio);
1717
1718                /* this will also unplug the queue */
1719                wait_for_completion(&complete);
1720
1721                if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
1722                        printk(KERN_INFO
1723                               "btrfsic: read error at logical %llu dev %s!\n",
1724                               block_ctx->start, block_ctx->dev->name);
1725                        bio_put(bio);
1726                        return -1;
1727                }
1728                bio_put(bio);
1729                dev_bytenr += (j - i) * PAGE_CACHE_SIZE;
1730                i = j;
1731        }
1732        for (i = 0; i < num_pages; i++) {
1733                block_ctx->datav[i] = kmap(block_ctx->pagev[i]);
1734                if (!block_ctx->datav[i]) {
1735                        printk(KERN_INFO "btrfsic: kmap() failed (dev %s)!\n",
1736                               block_ctx->dev->name);
1737                        return -1;
1738                }
1739        }
1740
1741        return block_ctx->len;
1742}
1743
1744static void btrfsic_complete_bio_end_io(struct bio *bio, int err)
1745{
1746        complete((struct completion *)bio->bi_private);
1747}
1748
1749static void btrfsic_dump_database(struct btrfsic_state *state)
1750{
1751        struct list_head *elem_all;
1752
1753        BUG_ON(NULL == state);
1754
1755        printk(KERN_INFO "all_blocks_list:\n");
1756        list_for_each(elem_all, &state->all_blocks_list) {
1757                const struct btrfsic_block *const b_all =
1758                    list_entry(elem_all, struct btrfsic_block,
1759                               all_blocks_node);
1760                struct list_head *elem_ref_to;
1761                struct list_head *elem_ref_from;
1762
1763                printk(KERN_INFO "%c-block @%llu (%s/%llu/%d)\n",
1764                       btrfsic_get_block_type(state, b_all),
1765                       (unsigned long long)b_all->logical_bytenr,
1766                       b_all->dev_state->name,
1767                       (unsigned long long)b_all->dev_bytenr,
1768                       b_all->mirror_num);
1769
1770                list_for_each(elem_ref_to, &b_all->ref_to_list) {
1771                        const struct btrfsic_block_link *const l =
1772                            list_entry(elem_ref_to,
1773                                       struct btrfsic_block_link,
1774                                       node_ref_to);
1775
1776                        printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1777                               " refers %u* to"
1778                               " %c @%llu (%s/%llu/%d)\n",
1779                               btrfsic_get_block_type(state, b_all),
1780                               (unsigned long long)b_all->logical_bytenr,
1781                               b_all->dev_state->name,
1782                               (unsigned long long)b_all->dev_bytenr,
1783                               b_all->mirror_num,
1784                               l->ref_cnt,
1785                               btrfsic_get_block_type(state, l->block_ref_to),
1786                               (unsigned long long)
1787                               l->block_ref_to->logical_bytenr,
1788                               l->block_ref_to->dev_state->name,
1789                               (unsigned long long)l->block_ref_to->dev_bytenr,
1790                               l->block_ref_to->mirror_num);
1791                }
1792
1793                list_for_each(elem_ref_from, &b_all->ref_from_list) {
1794                        const struct btrfsic_block_link *const l =
1795                            list_entry(elem_ref_from,
1796                                       struct btrfsic_block_link,
1797                                       node_ref_from);
1798
1799                        printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1800                               " is ref %u* from"
1801                               " %c @%llu (%s/%llu/%d)\n",
1802                               btrfsic_get_block_type(state, b_all),
1803                               (unsigned long long)b_all->logical_bytenr,
1804                               b_all->dev_state->name,
1805                               (unsigned long long)b_all->dev_bytenr,
1806                               b_all->mirror_num,
1807                               l->ref_cnt,
1808                               btrfsic_get_block_type(state, l->block_ref_from),
1809                               (unsigned long long)
1810                               l->block_ref_from->logical_bytenr,
1811                               l->block_ref_from->dev_state->name,
1812                               (unsigned long long)
1813                               l->block_ref_from->dev_bytenr,
1814                               l->block_ref_from->mirror_num);
1815                }
1816
1817                printk(KERN_INFO "\n");
1818        }
1819}
1820
1821/*
1822 * Test whether the disk block contains a tree block (leaf or node)
1823 * (note that this test fails for the super block)
1824 */
1825static int btrfsic_test_for_metadata(struct btrfsic_state *state,
1826                                     char **datav, unsigned int num_pages)
1827{
1828        struct btrfs_header *h;
1829        u8 csum[BTRFS_CSUM_SIZE];
1830        u32 crc = ~(u32)0;
1831        unsigned int i;
1832
1833        if (num_pages * PAGE_CACHE_SIZE < state->metablock_size)
1834                return 1; /* not metadata */
1835        num_pages = state->metablock_size >> PAGE_CACHE_SHIFT;
1836        h = (struct btrfs_header *)datav[0];
1837
1838        if (memcmp(h->fsid, state->root->fs_info->fsid, BTRFS_UUID_SIZE))
1839                return 1;
1840
1841        for (i = 0; i < num_pages; i++) {
1842                u8 *data = i ? datav[i] : (datav[i] + BTRFS_CSUM_SIZE);
1843                size_t sublen = i ? PAGE_CACHE_SIZE :
1844                                    (PAGE_CACHE_SIZE - BTRFS_CSUM_SIZE);
1845
1846                crc = crc32c(crc, data, sublen);
1847        }
1848        btrfs_csum_final(crc, csum);
1849        if (memcmp(csum, h->csum, state->csum_size))
1850                return 1;
1851
1852        return 0; /* is metadata */
1853}
1854
1855static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
1856                                          u64 dev_bytenr, char **mapped_datav,
1857                                          unsigned int num_pages,
1858                                          struct bio *bio, int *bio_is_patched,
1859                                          struct buffer_head *bh,
1860                                          int submit_bio_bh_rw)
1861{
1862        int is_metadata;
1863        struct btrfsic_block *block;
1864        struct btrfsic_block_data_ctx block_ctx;
1865        int ret;
1866        struct btrfsic_state *state = dev_state->state;
1867        struct block_device *bdev = dev_state->bdev;
1868        unsigned int processed_len;
1869
1870        if (NULL != bio_is_patched)
1871                *bio_is_patched = 0;
1872
1873again:
1874        if (num_pages == 0)
1875                return;
1876
1877        processed_len = 0;
1878        is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_datav,
1879                                                      num_pages));
1880
1881        block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
1882                                               &state->block_hashtable);
1883        if (NULL != block) {
1884                u64 bytenr = 0;
1885                struct list_head *elem_ref_to;
1886                struct list_head *tmp_ref_to;
1887
1888                if (block->is_superblock) {
1889                        bytenr = le64_to_cpu(((struct btrfs_super_block *)
1890                                              mapped_datav[0])->bytenr);
1891                        if (num_pages * PAGE_CACHE_SIZE <
1892                            BTRFS_SUPER_INFO_SIZE) {
1893                                printk(KERN_INFO
1894                                       "btrfsic: cannot work with too short bios!\n");
1895                                return;
1896                        }
1897                        is_metadata = 1;
1898                        BUG_ON(BTRFS_SUPER_INFO_SIZE & (PAGE_CACHE_SIZE - 1));
1899                        processed_len = BTRFS_SUPER_INFO_SIZE;
1900                        if (state->print_mask &
1901                            BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
1902                                printk(KERN_INFO
1903                                       "[before new superblock is written]:\n");
1904                                btrfsic_dump_tree_sub(state, block, 0);
1905                        }
1906                }
1907                if (is_metadata) {
1908                        if (!block->is_superblock) {
1909                                if (num_pages * PAGE_CACHE_SIZE <
1910                                    state->metablock_size) {
1911                                        printk(KERN_INFO
1912                                               "btrfsic: cannot work with too short bios!\n");
1913                                        return;
1914                                }
1915                                processed_len = state->metablock_size;
1916                                bytenr = le64_to_cpu(((struct btrfs_header *)
1917                                                      mapped_datav[0])->bytenr);
1918                                btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
1919                                                               dev_state,
1920                                                               dev_bytenr);
1921                        }
1922                        if (block->logical_bytenr != bytenr) {
1923                                printk(KERN_INFO
1924                                       "Written block @%llu (%s/%llu/%d)"
1925                                       " found in hash table, %c,"
1926                                       " bytenr mismatch"
1927                                       " (!= stored %llu).\n",
1928                                       (unsigned long long)bytenr,
1929                                       dev_state->name,
1930                                       (unsigned long long)dev_bytenr,
1931                                       block->mirror_num,
1932                                       btrfsic_get_block_type(state, block),
1933                                       (unsigned long long)
1934                                       block->logical_bytenr);
1935                                block->logical_bytenr = bytenr;
1936                        } else if (state->print_mask &
1937                                   BTRFSIC_PRINT_MASK_VERBOSE)
1938                                printk(KERN_INFO
1939                                       "Written block @%llu (%s/%llu/%d)"
1940                                       " found in hash table, %c.\n",
1941                                       (unsigned long long)bytenr,
1942                                       dev_state->name,
1943                                       (unsigned long long)dev_bytenr,
1944                                       block->mirror_num,
1945                                       btrfsic_get_block_type(state, block));
1946                } else {
1947                        if (num_pages * PAGE_CACHE_SIZE <
1948                            state->datablock_size) {
1949                                printk(KERN_INFO
1950                                       "btrfsic: cannot work with too short bios!\n");
1951                                return;
1952                        }
1953                        processed_len = state->datablock_size;
1954                        bytenr = block->logical_bytenr;
1955                        if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1956                                printk(KERN_INFO
1957                                       "Written block @%llu (%s/%llu/%d)"
1958                                       " found in hash table, %c.\n",
1959                                       (unsigned long long)bytenr,
1960                                       dev_state->name,
1961                                       (unsigned long long)dev_bytenr,
1962                                       block->mirror_num,
1963                                       btrfsic_get_block_type(state, block));
1964                }
1965
1966                if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1967                        printk(KERN_INFO
1968                               "ref_to_list: %cE, ref_from_list: %cE\n",
1969                               list_empty(&block->ref_to_list) ? ' ' : '!',
1970                               list_empty(&block->ref_from_list) ? ' ' : '!');
1971                if (btrfsic_is_block_ref_by_superblock(state, block, 0)) {
1972                        printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
1973                               " @%llu (%s/%llu/%d), old(gen=%llu,"
1974                               " objectid=%llu, type=%d, offset=%llu),"
1975                               " new(gen=%llu),"
1976                               " which is referenced by most recent superblock"
1977                               " (superblockgen=%llu)!\n",
1978                               btrfsic_get_block_type(state, block),
1979                               (unsigned long long)bytenr,
1980                               dev_state->name,
1981                               (unsigned long long)dev_bytenr,
1982                               block->mirror_num,
1983                               (unsigned long long)block->generation,
1984                               (unsigned long long)
1985                               le64_to_cpu(block->disk_key.objectid),
1986                               block->disk_key.type,
1987                               (unsigned long long)
1988                               le64_to_cpu(block->disk_key.offset),
1989                               (unsigned long long)
1990                               le64_to_cpu(((struct btrfs_header *)
1991                                            mapped_datav[0])->generation),
1992                               (unsigned long long)
1993                               state->max_superblock_generation);
1994                        btrfsic_dump_tree(state);
1995                }
1996
1997                if (!block->is_iodone && !block->never_written) {
1998                        printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
1999                               " @%llu (%s/%llu/%d), oldgen=%llu, newgen=%llu,"
2000                               " which is not yet iodone!\n",
2001                               btrfsic_get_block_type(state, block),
2002                               (unsigned long long)bytenr,
2003                               dev_state->name,
2004                               (unsigned long long)dev_bytenr,
2005                               block->mirror_num,
2006                               (unsigned long long)block->generation,
2007                               (unsigned long long)
2008                               le64_to_cpu(((struct btrfs_header *)
2009                                            mapped_datav[0])->generation));
2010                        /* it would not be safe to go on */
2011                        btrfsic_dump_tree(state);
2012                        goto continue_loop;
2013                }
2014
2015                /*
2016                 * Clear all references of this block. Do not free
2017                 * the block itself even if is not referenced anymore
2018                 * because it still carries valueable information
2019                 * like whether it was ever written and IO completed.
2020                 */
2021                list_for_each_safe(elem_ref_to, tmp_ref_to,
2022                                   &block->ref_to_list) {
2023                        struct btrfsic_block_link *const l =
2024                            list_entry(elem_ref_to,
2025                                       struct btrfsic_block_link,
2026                                       node_ref_to);
2027
2028                        if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2029                                btrfsic_print_rem_link(state, l);
2030                        l->ref_cnt--;
2031                        if (0 == l->ref_cnt) {
2032                                list_del(&l->node_ref_to);
2033                                list_del(&l->node_ref_from);
2034                                btrfsic_block_link_hashtable_remove(l);
2035                                btrfsic_block_link_free(l);
2036                        }
2037                }
2038
2039                if (block->is_superblock)
2040                        ret = btrfsic_map_superblock(state, bytenr,
2041                                                     processed_len,
2042                                                     bdev, &block_ctx);
2043                else
2044                        ret = btrfsic_map_block(state, bytenr, processed_len,
2045                                                &block_ctx, 0);
2046                if (ret) {
2047                        printk(KERN_INFO
2048                               "btrfsic: btrfsic_map_block(root @%llu)"
2049                               " failed!\n", (unsigned long long)bytenr);
2050                        goto continue_loop;
2051                }
2052                block_ctx.datav = mapped_datav;
2053                /* the following is required in case of writes to mirrors,
2054                 * use the same that was used for the lookup */
2055                block_ctx.dev = dev_state;
2056                block_ctx.dev_bytenr = dev_bytenr;
2057
2058                if (is_metadata || state->include_extent_data) {
2059                        block->never_written = 0;
2060                        block->iodone_w_error = 0;
2061                        if (NULL != bio) {
2062                                block->is_iodone = 0;
2063                                BUG_ON(NULL == bio_is_patched);
2064                                if (!*bio_is_patched) {
2065                                        block->orig_bio_bh_private =
2066                                            bio->bi_private;
2067                                        block->orig_bio_bh_end_io.bio =
2068                                            bio->bi_end_io;
2069                                        block->next_in_same_bio = NULL;
2070                                        bio->bi_private = block;
2071                                        bio->bi_end_io = btrfsic_bio_end_io;
2072                                        *bio_is_patched = 1;
2073                                } else {
2074                                        struct btrfsic_block *chained_block =
2075                                            (struct btrfsic_block *)
2076                                            bio->bi_private;
2077
2078                                        BUG_ON(NULL == chained_block);
2079                                        block->orig_bio_bh_private =
2080                                            chained_block->orig_bio_bh_private;
2081                                        block->orig_bio_bh_end_io.bio =
2082                                            chained_block->orig_bio_bh_end_io.
2083                                            bio;
2084                                        block->next_in_same_bio = chained_block;
2085                                        bio->bi_private = block;
2086                                }
2087                        } else if (NULL != bh) {
2088                                block->is_iodone = 0;
2089                                block->orig_bio_bh_private = bh->b_private;
2090                                block->orig_bio_bh_end_io.bh = bh->b_end_io;
2091                                block->next_in_same_bio = NULL;
2092                                bh->b_private = block;
2093                                bh->b_end_io = btrfsic_bh_end_io;
2094                        } else {
2095                                block->is_iodone = 1;
2096                                block->orig_bio_bh_private = NULL;
2097                                block->orig_bio_bh_end_io.bio = NULL;
2098                                block->next_in_same_bio = NULL;
2099                        }
2100                }
2101
2102                block->flush_gen = dev_state->last_flush_gen + 1;
2103                block->submit_bio_bh_rw = submit_bio_bh_rw;
2104                if (is_metadata) {
2105                        block->logical_bytenr = bytenr;
2106                        block->is_metadata = 1;
2107                        if (block->is_superblock) {
2108                                BUG_ON(PAGE_CACHE_SIZE !=
2109                                       BTRFS_SUPER_INFO_SIZE);
2110                                ret = btrfsic_process_written_superblock(
2111                                                state,
2112                                                block,
2113                                                (struct btrfs_super_block *)
2114                                                mapped_datav[0]);
2115                                if (state->print_mask &
2116                                    BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE) {
2117                                        printk(KERN_INFO
2118                                        "[after new superblock is written]:\n");
2119                                        btrfsic_dump_tree_sub(state, block, 0);
2120                                }
2121                        } else {
2122                                block->mirror_num = 0;  /* unknown */
2123                                ret = btrfsic_process_metablock(
2124                                                state,
2125                                                block,
2126                                                &block_ctx,
2127                                                0, 0);
2128                        }
2129                        if (ret)
2130                                printk(KERN_INFO
2131                                       "btrfsic: btrfsic_process_metablock"
2132                                       "(root @%llu) failed!\n",
2133                                       (unsigned long long)dev_bytenr);
2134                } else {
2135                        block->is_metadata = 0;
2136                        block->mirror_num = 0;  /* unknown */
2137                        block->generation = BTRFSIC_GENERATION_UNKNOWN;
2138                        if (!state->include_extent_data
2139                            && list_empty(&block->ref_from_list)) {
2140                                /*
2141                                 * disk block is overwritten with extent
2142                                 * data (not meta data) and we are configured
2143                                 * to not include extent data: take the
2144                                 * chance and free the block's memory
2145                                 */
2146                                btrfsic_block_hashtable_remove(block);
2147                                list_del(&block->all_blocks_node);
2148                                btrfsic_block_free(block);
2149                        }
2150                }
2151                btrfsic_release_block_ctx(&block_ctx);
2152        } else {
2153                /* block has not been found in hash table */
2154                u64 bytenr;
2155
2156                if (!is_metadata) {
2157                        processed_len = state->datablock_size;
2158                        if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2159                                printk(KERN_INFO "Written block (%s/%llu/?)"
2160                                       " !found in hash table, D.\n",
2161                                       dev_state->name,
2162                                       (unsigned long long)dev_bytenr);
2163                        if (!state->include_extent_data) {
2164                                /* ignore that written D block */
2165                                goto continue_loop;
2166                        }
2167
2168                        /* this is getting ugly for the
2169                         * include_extent_data case... */
2170                        bytenr = 0;     /* unknown */
2171                        block_ctx.start = bytenr;
2172                        block_ctx.len = processed_len;
2173                        block_ctx.mem_to_free = NULL;
2174                        block_ctx.pagev = NULL;
2175                } else {
2176                        processed_len = state->metablock_size;
2177                        bytenr = le64_to_cpu(((struct btrfs_header *)
2178                                              mapped_datav[0])->bytenr);
2179                        btrfsic_cmp_log_and_dev_bytenr(state, bytenr, dev_state,
2180                                                       dev_bytenr);
2181                        if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2182                                printk(KERN_INFO
2183                                       "Written block @%llu (%s/%llu/?)"
2184                                       " !found in hash table, M.\n",
2185                                       (unsigned long long)bytenr,
2186                                       dev_state->name,
2187                                       (unsigned long long)dev_bytenr);
2188
2189                        ret = btrfsic_map_block(state, bytenr, processed_len,
2190                                                &block_ctx, 0);
2191                        if (ret) {
2192                                printk(KERN_INFO
2193                                       "btrfsic: btrfsic_map_block(root @%llu)"
2194                                       " failed!\n",
2195                                       (unsigned long long)dev_bytenr);
2196                                goto continue_loop;
2197                        }
2198                }
2199                block_ctx.datav = mapped_datav;
2200                /* the following is required in case of writes to mirrors,
2201                 * use the same that was used for the lookup */
2202                block_ctx.dev = dev_state;
2203                block_ctx.dev_bytenr = dev_bytenr;
2204
2205                block = btrfsic_block_alloc();
2206                if (NULL == block) {
2207                        printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2208                        btrfsic_release_block_ctx(&block_ctx);
2209                        goto continue_loop;
2210                }
2211                block->dev_state = dev_state;
2212                block->dev_bytenr = dev_bytenr;
2213                block->logical_bytenr = bytenr;
2214                block->is_metadata = is_metadata;
2215                block->never_written = 0;
2216                block->iodone_w_error = 0;
2217                block->mirror_num = 0;  /* unknown */
2218                block->flush_gen = dev_state->last_flush_gen + 1;
2219                block->submit_bio_bh_rw = submit_bio_bh_rw;
2220                if (NULL != bio) {
2221                        block->is_iodone = 0;
2222                        BUG_ON(NULL == bio_is_patched);
2223                        if (!*bio_is_patched) {
2224                                block->orig_bio_bh_private = bio->bi_private;
2225                                block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2226                                block->next_in_same_bio = NULL;
2227                                bio->bi_private = block;
2228                                bio->bi_end_io = btrfsic_bio_end_io;
2229                                *bio_is_patched = 1;
2230                        } else {
2231                                struct btrfsic_block *chained_block =
2232                                    (struct btrfsic_block *)
2233                                    bio->bi_private;
2234
2235                                BUG_ON(NULL == chained_block);
2236                                block->orig_bio_bh_private =
2237                                    chained_block->orig_bio_bh_private;
2238                                block->orig_bio_bh_end_io.bio =
2239                                    chained_block->orig_bio_bh_end_io.bio;
2240                                block->next_in_same_bio = chained_block;
2241                                bio->bi_private = block;
2242                        }
2243                } else if (NULL != bh) {
2244                        block->is_iodone = 0;
2245                        block->orig_bio_bh_private = bh->b_private;
2246                        block->orig_bio_bh_end_io.bh = bh->b_end_io;
2247                        block->next_in_same_bio = NULL;
2248                        bh->b_private = block;
2249                        bh->b_end_io = btrfsic_bh_end_io;
2250                } else {
2251                        block->is_iodone = 1;
2252                        block->orig_bio_bh_private = NULL;
2253                        block->orig_bio_bh_end_io.bio = NULL;
2254                        block->next_in_same_bio = NULL;
2255                }
2256                if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2257                        printk(KERN_INFO
2258                               "New written %c-block @%llu (%s/%llu/%d)\n",
2259                               is_metadata ? 'M' : 'D',
2260                               (unsigned long long)block->logical_bytenr,
2261                               block->dev_state->name,
2262                               (unsigned long long)block->dev_bytenr,
2263                               block->mirror_num);
2264                list_add(&block->all_blocks_node, &state->all_blocks_list);
2265                btrfsic_block_hashtable_add(block, &state->block_hashtable);
2266
2267                if (is_metadata) {
2268                        ret = btrfsic_process_metablock(state, block,
2269                                                        &block_ctx, 0, 0);
2270                        if (ret)
2271                                printk(KERN_INFO
2272                                       "btrfsic: process_metablock(root @%llu)"
2273                                       " failed!\n",
2274                                       (unsigned long long)dev_bytenr);
2275                }
2276                btrfsic_release_block_ctx(&block_ctx);
2277        }
2278
2279continue_loop:
2280        BUG_ON(!processed_len);
2281        dev_bytenr += processed_len;
2282        mapped_datav += processed_len >> PAGE_CACHE_SHIFT;
2283        num_pages -= processed_len >> PAGE_CACHE_SHIFT;
2284        goto again;
2285}
2286
2287static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status)
2288{
2289        struct btrfsic_block *block = (struct btrfsic_block *)bp->bi_private;
2290        int iodone_w_error;
2291
2292        /* mutex is not held! This is not save if IO is not yet completed
2293         * on umount */
2294        iodone_w_error = 0;
2295        if (bio_error_status)
2296                iodone_w_error = 1;
2297
2298        BUG_ON(NULL == block);
2299        bp->bi_private = block->orig_bio_bh_private;
2300        bp->bi_end_io = block->orig_bio_bh_end_io.bio;
2301
2302        do {
2303                struct btrfsic_block *next_block;
2304                struct btrfsic_dev_state *const dev_state = block->dev_state;
2305
2306                if ((dev_state->state->print_mask &
2307                     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2308                        printk(KERN_INFO
2309                               "bio_end_io(err=%d) for %c @%llu (%s/%llu/%d)\n",
2310                               bio_error_status,
2311                               btrfsic_get_block_type(dev_state->state, block),
2312                               (unsigned long long)block->logical_bytenr,
2313                               dev_state->name,
2314                               (unsigned long long)block->dev_bytenr,
2315                               block->mirror_num);
2316                next_block = block->next_in_same_bio;
2317                block->iodone_w_error = iodone_w_error;
2318                if (block->submit_bio_bh_rw & REQ_FLUSH) {
2319                        dev_state->last_flush_gen++;
2320                        if ((dev_state->state->print_mask &
2321                             BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2322                                printk(KERN_INFO
2323                                       "bio_end_io() new %s flush_gen=%llu\n",
2324                                       dev_state->name,
2325                                       (unsigned long long)
2326                                       dev_state->last_flush_gen);
2327                }
2328                if (block->submit_bio_bh_rw & REQ_FUA)
2329                        block->flush_gen = 0; /* FUA completed means block is
2330                                               * on disk */
2331                block->is_iodone = 1; /* for FLUSH, this releases the block */
2332                block = next_block;
2333        } while (NULL != block);
2334
2335        bp->bi_end_io(bp, bio_error_status);
2336}
2337
2338static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate)
2339{
2340        struct btrfsic_block *block = (struct btrfsic_block *)bh->b_private;
2341        int iodone_w_error = !uptodate;
2342        struct btrfsic_dev_state *dev_state;
2343
2344        BUG_ON(NULL == block);
2345        dev_state = block->dev_state;
2346        if ((dev_state->state->print_mask & BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2347                printk(KERN_INFO
2348                       "bh_end_io(error=%d) for %c @%llu (%s/%llu/%d)\n",
2349                       iodone_w_error,
2350                       btrfsic_get_block_type(dev_state->state, block),
2351                       (unsigned long long)block->logical_bytenr,
2352                       block->dev_state->name,
2353                       (unsigned long long)block->dev_bytenr,
2354                       block->mirror_num);
2355
2356        block->iodone_w_error = iodone_w_error;
2357        if (block->submit_bio_bh_rw & REQ_FLUSH) {
2358                dev_state->last_flush_gen++;
2359                if ((dev_state->state->print_mask &
2360                     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2361                        printk(KERN_INFO
2362                               "bh_end_io() new %s flush_gen=%llu\n",
2363                               dev_state->name,
2364                               (unsigned long long)dev_state->last_flush_gen);
2365        }
2366        if (block->submit_bio_bh_rw & REQ_FUA)
2367                block->flush_gen = 0; /* FUA completed means block is on disk */
2368
2369        bh->b_private = block->orig_bio_bh_private;
2370        bh->b_end_io = block->orig_bio_bh_end_io.bh;
2371        block->is_iodone = 1; /* for FLUSH, this releases the block */
2372        bh->b_end_io(bh, uptodate);
2373}
2374
2375static int btrfsic_process_written_superblock(
2376                struct btrfsic_state *state,
2377                struct btrfsic_block *const superblock,
2378                struct btrfs_super_block *const super_hdr)
2379{
2380        int pass;
2381
2382        superblock->generation = btrfs_super_generation(super_hdr);
2383        if (!(superblock->generation > state->max_superblock_generation ||
2384              0 == state->max_superblock_generation)) {
2385                if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2386                        printk(KERN_INFO
2387                               "btrfsic: superblock @%llu (%s/%llu/%d)"
2388                               " with old gen %llu <= %llu\n",
2389                               (unsigned long long)superblock->logical_bytenr,
2390                               superblock->dev_state->name,
2391                               (unsigned long long)superblock->dev_bytenr,
2392                               superblock->mirror_num,
2393                               (unsigned long long)
2394                               btrfs_super_generation(super_hdr),
2395                               (unsigned long long)
2396                               state->max_superblock_generation);
2397        } else {
2398                if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2399                        printk(KERN_INFO
2400                               "btrfsic: got new superblock @%llu (%s/%llu/%d)"
2401                               " with new gen %llu > %llu\n",
2402                               (unsigned long long)superblock->logical_bytenr,
2403                               superblock->dev_state->name,
2404                               (unsigned long long)superblock->dev_bytenr,
2405                               superblock->mirror_num,
2406                               (unsigned long long)
2407                               btrfs_super_generation(super_hdr),
2408                               (unsigned long long)
2409                               state->max_superblock_generation);
2410
2411                state->max_superblock_generation =
2412                    btrfs_super_generation(super_hdr);
2413                state->latest_superblock = superblock;
2414        }
2415
2416        for (pass = 0; pass < 3; pass++) {
2417                int ret;
2418                u64 next_bytenr;
2419                struct btrfsic_block *next_block;
2420                struct btrfsic_block_data_ctx tmp_next_block_ctx;
2421                struct btrfsic_block_link *l;
2422                int num_copies;
2423                int mirror_num;
2424                const char *additional_string = NULL;
2425                struct btrfs_disk_key tmp_disk_key;
2426
2427                tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
2428                tmp_disk_key.offset = 0;
2429
2430                switch (pass) {
2431                case 0:
2432                        tmp_disk_key.objectid =
2433                            cpu_to_le64(BTRFS_ROOT_TREE_OBJECTID);
2434                        additional_string = "root ";
2435                        next_bytenr = btrfs_super_root(super_hdr);
2436                        if (state->print_mask &
2437                            BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2438                                printk(KERN_INFO "root@%llu\n",
2439                                       (unsigned long long)next_bytenr);
2440                        break;
2441                case 1:
2442                        tmp_disk_key.objectid =
2443                            cpu_to_le64(BTRFS_CHUNK_TREE_OBJECTID);
2444                        additional_string = "chunk ";
2445                        next_bytenr = btrfs_super_chunk_root(super_hdr);
2446                        if (state->print_mask &
2447                            BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2448                                printk(KERN_INFO "chunk@%llu\n",
2449                                       (unsigned long long)next_bytenr);
2450                        break;
2451                case 2:
2452                        tmp_disk_key.objectid =
2453                            cpu_to_le64(BTRFS_TREE_LOG_OBJECTID);
2454                        additional_string = "log ";
2455                        next_bytenr = btrfs_super_log_root(super_hdr);
2456                        if (0 == next_bytenr)
2457                                continue;
2458                        if (state->print_mask &
2459                            BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2460                                printk(KERN_INFO "log@%llu\n",
2461                                       (unsigned long long)next_bytenr);
2462                        break;
2463                }
2464
2465                num_copies =
2466                    btrfs_num_copies(&state->root->fs_info->mapping_tree,
2467                                     next_bytenr, BTRFS_SUPER_INFO_SIZE);
2468                if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
2469                        printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
2470                               (unsigned long long)next_bytenr, num_copies);
2471                for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2472                        int was_created;
2473
2474                        if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2475                                printk(KERN_INFO
2476                                       "btrfsic_process_written_superblock("
2477                                       "mirror_num=%d)\n", mirror_num);
2478                        ret = btrfsic_map_block(state, next_bytenr,
2479                                                BTRFS_SUPER_INFO_SIZE,
2480                                                &tmp_next_block_ctx,
2481                                                mirror_num);
2482                        if (ret) {
2483                                printk(KERN_INFO
2484                                       "btrfsic: btrfsic_map_block(@%llu,"
2485                                       " mirror=%d) failed!\n",
2486                                       (unsigned long long)next_bytenr,
2487                                       mirror_num);
2488                                return -1;
2489                        }
2490
2491                        next_block = btrfsic_block_lookup_or_add(
2492                                        state,
2493                                        &tmp_next_block_ctx,
2494                                        additional_string,
2495                                        1, 0, 1,
2496                                        mirror_num,
2497                                        &was_created);
2498                        if (NULL == next_block) {
2499                                printk(KERN_INFO
2500                                       "btrfsic: error, kmalloc failed!\n");
2501                                btrfsic_release_block_ctx(&tmp_next_block_ctx);
2502                                return -1;
2503                        }
2504
2505                        next_block->disk_key = tmp_disk_key;
2506                        if (was_created)
2507                                next_block->generation =
2508                                    BTRFSIC_GENERATION_UNKNOWN;
2509                        l = btrfsic_block_link_lookup_or_add(
2510                                        state,
2511                                        &tmp_next_block_ctx,
2512                                        next_block,
2513                                        superblock,
2514                                        BTRFSIC_GENERATION_UNKNOWN);
2515                        btrfsic_release_block_ctx(&tmp_next_block_ctx);
2516                        if (NULL == l)
2517                                return -1;
2518                }
2519        }
2520
2521        if (-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)) {
2522                WARN_ON(1);
2523                btrfsic_dump_tree(state);
2524        }
2525
2526        return 0;
2527}
2528
2529static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
2530                                        struct btrfsic_block *const block,
2531                                        int recursion_level)
2532{
2533        struct list_head *elem_ref_to;
2534        int ret = 0;
2535
2536        if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2537                /*
2538                 * Note that this situation can happen and does not
2539                 * indicate an error in regular cases. It happens
2540                 * when disk blocks are freed and later reused.
2541                 * The check-integrity module is not aware of any
2542                 * block free operations, it just recognizes block
2543                 * write operations. Therefore it keeps the linkage
2544                 * information for a block until a block is
2545                 * rewritten. This can temporarily cause incorrect
2546                 * and even circular linkage informations. This
2547                 * causes no harm unless such blocks are referenced
2548                 * by the most recent super block.
2549                 */
2550                if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2551                        printk(KERN_INFO
2552                               "btrfsic: abort cyclic linkage (case 1).\n");
2553
2554                return ret;
2555        }
2556
2557        /*
2558         * This algorithm is recursive because the amount of used stack
2559         * space is very small and the max recursion depth is limited.
2560         */
2561        list_for_each(elem_ref_to, &block->ref_to_list) {
2562                const struct btrfsic_block_link *const l =
2563                    list_entry(elem_ref_to, struct btrfsic_block_link,
2564                               node_ref_to);
2565
2566                if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2567                        printk(KERN_INFO
2568                               "rl=%d, %c @%llu (%s/%llu/%d)"
2569                               " %u* refers to %c @%llu (%s/%llu/%d)\n",
2570                               recursion_level,
2571                               btrfsic_get_block_type(state, block),
2572                               (unsigned long long)block->logical_bytenr,
2573                               block->dev_state->name,
2574                               (unsigned long long)block->dev_bytenr,
2575                               block->mirror_num,
2576                               l->ref_cnt,
2577                               btrfsic_get_block_type(state, l->block_ref_to),
2578                               (unsigned long long)
2579                               l->block_ref_to->logical_bytenr,
2580                               l->block_ref_to->dev_state->name,
2581                               (unsigned long long)l->block_ref_to->dev_bytenr,
2582                               l->block_ref_to->mirror_num);
2583                if (l->block_ref_to->never_written) {
2584                        printk(KERN_INFO "btrfs: attempt to write superblock"
2585                               " which references block %c @%llu (%s/%llu/%d)"
2586                               " which is never written!\n",
2587                               btrfsic_get_block_type(state, l->block_ref_to),
2588                               (unsigned long long)
2589                               l->block_ref_to->logical_bytenr,
2590                               l->block_ref_to->dev_state->name,
2591                               (unsigned long long)l->block_ref_to->dev_bytenr,
2592                               l->block_ref_to->mirror_num);
2593                        ret = -1;
2594                } else if (!l->block_ref_to->is_iodone) {
2595                        printk(KERN_INFO "btrfs: attempt to write superblock"
2596                               " which references block %c @%llu (%s/%llu/%d)"
2597                               " which is not yet iodone!\n",
2598                               btrfsic_get_block_type(state, l->block_ref_to),
2599                               (unsigned long long)
2600                               l->block_ref_to->logical_bytenr,
2601                               l->block_ref_to->dev_state->name,
2602                               (unsigned long long)l->block_ref_to->dev_bytenr,
2603                               l->block_ref_to->mirror_num);
2604                        ret = -1;
2605                } else if (l->block_ref_to->iodone_w_error) {
2606                        printk(KERN_INFO "btrfs: attempt to write superblock"
2607                               " which references block %c @%llu (%s/%llu/%d)"
2608                               " which has write error!\n",
2609                               btrfsic_get_block_type(state, l->block_ref_to),
2610                               (unsigned long long)
2611                               l->block_ref_to->logical_bytenr,
2612                               l->block_ref_to->dev_state->name,
2613                               (unsigned long long)l->block_ref_to->dev_bytenr,
2614                               l->block_ref_to->mirror_num);
2615                        ret = -1;
2616                } else if (l->parent_generation !=
2617                           l->block_ref_to->generation &&
2618                           BTRFSIC_GENERATION_UNKNOWN !=
2619                           l->parent_generation &&
2620                           BTRFSIC_GENERATION_UNKNOWN !=
2621                           l->block_ref_to->generation) {
2622                        printk(KERN_INFO "btrfs: attempt to write superblock"
2623                               " which references block %c @%llu (%s/%llu/%d)"
2624                               " with generation %llu !="
2625                               " parent generation %llu!\n",
2626                               btrfsic_get_block_type(state, l->block_ref_to),
2627                               (unsigned long long)
2628                               l->block_ref_to->logical_bytenr,
2629                               l->block_ref_to->dev_state->name,
2630                               (unsigned long long)l->block_ref_to->dev_bytenr,
2631                               l->block_ref_to->mirror_num,
2632                               (unsigned long long)l->block_ref_to->generation,
2633                               (unsigned long long)l->parent_generation);
2634                        ret = -1;
2635                } else if (l->block_ref_to->flush_gen >
2636                           l->block_ref_to->dev_state->last_flush_gen) {
2637                        printk(KERN_INFO "btrfs: attempt to write superblock"
2638                               " which references block %c @%llu (%s/%llu/%d)"
2639                               " which is not flushed out of disk's write cache"
2640                               " (block flush_gen=%llu,"
2641                               " dev->flush_gen=%llu)!\n",
2642                               btrfsic_get_block_type(state, l->block_ref_to),
2643                               (unsigned long long)
2644                               l->block_ref_to->logical_bytenr,
2645                               l->block_ref_to->dev_state->name,
2646                               (unsigned long long)l->block_ref_to->dev_bytenr,
2647                               l->block_ref_to->mirror_num,
2648                               (unsigned long long)block->flush_gen,
2649                               (unsigned long long)
2650                               l->block_ref_to->dev_state->last_flush_gen);
2651                        ret = -1;
2652                } else if (-1 == btrfsic_check_all_ref_blocks(state,
2653                                                              l->block_ref_to,
2654                                                              recursion_level +
2655                                                              1)) {
2656                        ret = -1;
2657                }
2658        }
2659
2660        return ret;
2661}
2662
2663static int btrfsic_is_block_ref_by_superblock(
2664                const struct btrfsic_state *state,
2665                const struct btrfsic_block *block,
2666                int recursion_level)
2667{
2668        struct list_head *elem_ref_from;
2669
2670        if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2671                /* refer to comment at "abort cyclic linkage (case 1)" */
2672                if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2673                        printk(KERN_INFO
2674                               "btrfsic: abort cyclic linkage (case 2).\n");
2675
2676                return 0;
2677        }
2678
2679        /*
2680         * This algorithm is recursive because the amount of used stack space
2681         * is very small and the max recursion depth is limited.
2682         */
2683        list_for_each(elem_ref_from, &block->ref_from_list) {
2684                const struct btrfsic_block_link *const l =
2685                    list_entry(elem_ref_from, struct btrfsic_block_link,
2686                               node_ref_from);
2687
2688                if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2689                        printk(KERN_INFO
2690                               "rl=%d, %c @%llu (%s/%llu/%d)"
2691                               " is ref %u* from %c @%llu (%s/%llu/%d)\n",
2692                               recursion_level,
2693                               btrfsic_get_block_type(state, block),
2694                               (unsigned long long)block->logical_bytenr,
2695                               block->dev_state->name,
2696                               (unsigned long long)block->dev_bytenr,
2697                               block->mirror_num,
2698                               l->ref_cnt,
2699                               btrfsic_get_block_type(state, l->block_ref_from),
2700                               (unsigned long long)
2701                               l->block_ref_from->logical_bytenr,
2702                               l->block_ref_from->dev_state->name,
2703                               (unsigned long long)
2704                               l->block_ref_from->dev_bytenr,
2705                               l->block_ref_from->mirror_num);
2706                if (l->block_ref_from->is_superblock &&
2707                    state->latest_superblock->dev_bytenr ==
2708                    l->block_ref_from->dev_bytenr &&
2709                    state->latest_superblock->dev_state->bdev ==
2710                    l->block_ref_from->dev_state->bdev)
2711                        return 1;
2712                else if (btrfsic_is_block_ref_by_superblock(state,
2713                                                            l->block_ref_from,
2714                                                            recursion_level +
2715                                                            1))
2716                        return 1;
2717        }
2718
2719        return 0;
2720}
2721
2722static void btrfsic_print_add_link(const struct btrfsic_state *state,
2723                                   const struct btrfsic_block_link *l)
2724{
2725        printk(KERN_INFO
2726               "Add %u* link from %c @%llu (%s/%llu/%d)"
2727               " to %c @%llu (%s/%llu/%d).\n",
2728               l->ref_cnt,
2729               btrfsic_get_block_type(state, l->block_ref_from),
2730               (unsigned long long)l->block_ref_from->logical_bytenr,
2731               l->block_ref_from->dev_state->name,
2732               (unsigned long long)l->block_ref_from->dev_bytenr,
2733               l->block_ref_from->mirror_num,
2734               btrfsic_get_block_type(state, l->block_ref_to),
2735               (unsigned long long)l->block_ref_to->logical_bytenr,
2736               l->block_ref_to->dev_state->name,
2737               (unsigned long long)l->block_ref_to->dev_bytenr,
2738               l->block_ref_to->mirror_num);
2739}
2740
2741static void btrfsic_print_rem_link(const struct btrfsic_state *state,
2742                                   const struct btrfsic_block_link *l)
2743{
2744        printk(KERN_INFO
2745               "Rem %u* link from %c @%llu (%s/%llu/%d)"
2746               " to %c @%llu (%s/%llu/%d).\n",
2747               l->ref_cnt,
2748               btrfsic_get_block_type(state, l->block_ref_from),
2749               (unsigned long long)l->block_ref_from->logical_bytenr,
2750               l->block_ref_from->dev_state->name,
2751               (unsigned long long)l->block_ref_from->dev_bytenr,
2752               l->block_ref_from->mirror_num,
2753               btrfsic_get_block_type(state, l->block_ref_to),
2754               (unsigned long long)l->block_ref_to->logical_bytenr,
2755               l->block_ref_to->dev_state->name,
2756               (unsigned long long)l->block_ref_to->dev_bytenr,
2757               l->block_ref_to->mirror_num);
2758}
2759
2760static char btrfsic_get_block_type(const struct btrfsic_state *state,
2761                                   const struct btrfsic_block *block)
2762{
2763        if (block->is_superblock &&
2764            state->latest_superblock->dev_bytenr == block->dev_bytenr &&
2765            state->latest_superblock->dev_state->bdev == block->dev_state->bdev)
2766                return 'S';
2767        else if (block->is_superblock)
2768                return 's';
2769        else if (block->is_metadata)
2770                return 'M';
2771        else
2772                return 'D';
2773}
2774
2775static void btrfsic_dump_tree(const struct btrfsic_state *state)
2776{
2777        btrfsic_dump_tree_sub(state, state->latest_superblock, 0);
2778}
2779
2780static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
2781                                  const struct btrfsic_block *block,
2782                                  int indent_level)
2783{
2784        struct list_head *elem_ref_to;
2785        int indent_add;
2786        static char buf[80];
2787        int cursor_position;
2788
2789        /*
2790         * Should better fill an on-stack buffer with a complete line and
2791         * dump it at once when it is time to print a newline character.
2792         */
2793
2794        /*
2795         * This algorithm is recursive because the amount of used stack space
2796         * is very small and the max recursion depth is limited.
2797         */
2798        indent_add = sprintf(buf, "%c-%llu(%s/%llu/%d)",
2799                             btrfsic_get_block_type(state, block),
2800                             (unsigned long long)block->logical_bytenr,
2801                             block->dev_state->name,
2802                             (unsigned long long)block->dev_bytenr,
2803                             block->mirror_num);
2804        if (indent_level + indent_add > BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2805                printk("[...]\n");
2806                return;
2807        }
2808        printk(buf);
2809        indent_level += indent_add;
2810        if (list_empty(&block->ref_to_list)) {
2811                printk("\n");
2812                return;
2813        }
2814        if (block->mirror_num > 1 &&
2815            !(state->print_mask & BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS)) {
2816                printk(" [...]\n");
2817                return;
2818        }
2819
2820        cursor_position = indent_level;
2821        list_for_each(elem_ref_to, &block->ref_to_list) {
2822                const struct btrfsic_block_link *const l =
2823                    list_entry(elem_ref_to, struct btrfsic_block_link,
2824                               node_ref_to);
2825
2826                while (cursor_position < indent_level) {
2827                        printk(" ");
2828                        cursor_position++;
2829                }
2830                if (l->ref_cnt > 1)
2831                        indent_add = sprintf(buf, " %d*--> ", l->ref_cnt);
2832                else
2833                        indent_add = sprintf(buf, " --> ");
2834                if (indent_level + indent_add >
2835                    BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2836                        printk("[...]\n");
2837                        cursor_position = 0;
2838                        continue;
2839                }
2840
2841                printk(buf);
2842
2843                btrfsic_dump_tree_sub(state, l->block_ref_to,
2844                                      indent_level + indent_add);
2845                cursor_position = 0;
2846        }
2847}
2848
2849static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
2850                struct btrfsic_state *state,
2851                struct btrfsic_block_data_ctx *next_block_ctx,
2852                struct btrfsic_block *next_block,
2853                struct btrfsic_block *from_block,
2854                u64 parent_generation)
2855{
2856        struct btrfsic_block_link *l;
2857
2858        l = btrfsic_block_link_hashtable_lookup(next_block_ctx->dev->bdev,
2859                                                next_block_ctx->dev_bytenr,
2860                                                from_block->dev_state->bdev,
2861                                                from_block->dev_bytenr,
2862                                                &state->block_link_hashtable);
2863        if (NULL == l) {
2864                l = btrfsic_block_link_alloc();
2865                if (NULL == l) {
2866                        printk(KERN_INFO
2867                               "btrfsic: error, kmalloc" " failed!\n");
2868                        return NULL;
2869                }
2870
2871                l->block_ref_to = next_block;
2872                l->block_ref_from = from_block;
2873                l->ref_cnt = 1;
2874                l->parent_generation = parent_generation;
2875
2876                if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2877                        btrfsic_print_add_link(state, l);
2878
2879                list_add(&l->node_ref_to, &from_block->ref_to_list);
2880                list_add(&l->node_ref_from, &next_block->ref_from_list);
2881
2882                btrfsic_block_link_hashtable_add(l,
2883                                                 &state->block_link_hashtable);
2884        } else {
2885                l->ref_cnt++;
2886                l->parent_generation = parent_generation;
2887                if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2888                        btrfsic_print_add_link(state, l);
2889        }
2890
2891        return l;
2892}
2893
2894static struct btrfsic_block *btrfsic_block_lookup_or_add(
2895                struct btrfsic_state *state,
2896                struct btrfsic_block_data_ctx *block_ctx,
2897                const char *additional_string,
2898                int is_metadata,
2899                int is_iodone,
2900                int never_written,
2901                int mirror_num,
2902                int *was_created)
2903{
2904        struct btrfsic_block *block;
2905
2906        block = btrfsic_block_hashtable_lookup(block_ctx->dev->bdev,
2907                                               block_ctx->dev_bytenr,
2908                                               &state->block_hashtable);
2909        if (NULL == block) {
2910                struct btrfsic_dev_state *dev_state;
2911
2912                block = btrfsic_block_alloc();
2913                if (NULL == block) {
2914                        printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2915                        return NULL;
2916                }
2917                dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev);
2918                if (NULL == dev_state) {
2919                        printk(KERN_INFO
2920                               "btrfsic: error, lookup dev_state failed!\n");
2921                        btrfsic_block_free(block);
2922                        return NULL;
2923                }
2924                block->dev_state = dev_state;
2925                block->dev_bytenr = block_ctx->dev_bytenr;
2926                block->logical_bytenr = block_ctx->start;
2927                block->is_metadata = is_metadata;
2928                block->is_iodone = is_iodone;
2929                block->never_written = never_written;
2930                block->mirror_num = mirror_num;
2931                if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2932                        printk(KERN_INFO
2933                               "New %s%c-block @%llu (%s/%llu/%d)\n",
2934                               additional_string,
2935                               btrfsic_get_block_type(state, block),
2936                               (unsigned long long)block->logical_bytenr,
2937                               dev_state->name,
2938                               (unsigned long long)block->dev_bytenr,
2939                               mirror_num);
2940                list_add(&block->all_blocks_node, &state->all_blocks_list);
2941                btrfsic_block_hashtable_add(block, &state->block_hashtable);
2942                if (NULL != was_created)
2943                        *was_created = 1;
2944        } else {
2945                if (NULL != was_created)
2946                        *was_created = 0;
2947        }
2948
2949        return block;
2950}
2951
2952static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
2953                                           u64 bytenr,
2954                                           struct btrfsic_dev_state *dev_state,
2955                                           u64 dev_bytenr)
2956{
2957        int num_copies;
2958        int mirror_num;
2959        int ret;
2960        struct btrfsic_block_data_ctx block_ctx;
2961        int match = 0;
2962
2963        num_copies = btrfs_num_copies(&state->root->fs_info->mapping_tree,
2964                                      bytenr, state->metablock_size);
2965
2966        for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2967                ret = btrfsic_map_block(state, bytenr, state->metablock_size,
2968                                        &block_ctx, mirror_num);
2969                if (ret) {
2970                        printk(KERN_INFO "btrfsic:"
2971                               " btrfsic_map_block(logical @%llu,"
2972                               " mirror %d) failed!\n",
2973                               (unsigned long long)bytenr, mirror_num);
2974                        continue;
2975                }
2976
2977                if (dev_state->bdev == block_ctx.dev->bdev &&
2978                    dev_bytenr == block_ctx.dev_bytenr) {
2979                        match++;
2980                        btrfsic_release_block_ctx(&block_ctx);
2981                        break;
2982                }
2983                btrfsic_release_block_ctx(&block_ctx);
2984        }
2985
2986        if (!match) {
2987                printk(KERN_INFO "btrfs: attempt to write M-block which contains logical bytenr that doesn't map to dev+physical bytenr of submit_bio,"
2988                       " buffer->log_bytenr=%llu, submit_bio(bdev=%s,"
2989                       " phys_bytenr=%llu)!\n",
2990                       (unsigned long long)bytenr, dev_state->name,
2991                       (unsigned long long)dev_bytenr);
2992                for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2993                        ret = btrfsic_map_block(state, bytenr,
2994                                                state->metablock_size,
2995                                                &block_ctx, mirror_num);
2996                        if (ret)
2997                                continue;
2998
2999                        printk(KERN_INFO "Read logical bytenr @%llu maps to"
3000                               " (%s/%llu/%d)\n",
3001                               (unsigned long long)bytenr,
3002                               block_ctx.dev->name,
3003                               (unsigned long long)block_ctx.dev_bytenr,
3004                               mirror_num);
3005                }
3006                WARN_ON(1);
3007        }
3008}
3009
3010static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
3011                struct block_device *bdev)
3012{
3013        struct btrfsic_dev_state *ds;
3014
3015        ds = btrfsic_dev_state_hashtable_lookup(bdev,
3016                                                &btrfsic_dev_state_hashtable);
3017        return ds;
3018}
3019
3020int btrfsic_submit_bh(int rw, struct buffer_head *bh)
3021{
3022        struct btrfsic_dev_state *dev_state;
3023
3024        if (!btrfsic_is_initialized)
3025                return submit_bh(rw, bh);
3026
3027        mutex_lock(&btrfsic_mutex);
3028        /* since btrfsic_submit_bh() might also be called before
3029         * btrfsic_mount(), this might return NULL */
3030        dev_state = btrfsic_dev_state_lookup(bh->b_bdev);
3031
3032        /* Only called to write the superblock (incl. FLUSH/FUA) */
3033        if (NULL != dev_state &&
3034            (rw & WRITE) && bh->b_size > 0) {
3035                u64 dev_bytenr;
3036
3037                dev_bytenr = 4096 * bh->b_blocknr;
3038                if (dev_state->state->print_mask &
3039                    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3040                        printk(KERN_INFO
3041                               "submit_bh(rw=0x%x, blocknr=%lu (bytenr %llu),"
3042                               " size=%lu, data=%p, bdev=%p)\n",
3043                               rw, (unsigned long)bh->b_blocknr,
3044                               (unsigned long long)dev_bytenr,
3045                               (unsigned long)bh->b_size, bh->b_data,
3046                               bh->b_bdev);
3047                btrfsic_process_written_block(dev_state, dev_bytenr,
3048                                              &bh->b_data, 1, NULL,
3049                                              NULL, bh, rw);
3050        } else if (NULL != dev_state && (rw & REQ_FLUSH)) {
3051                if (dev_state->state->print_mask &
3052                    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3053                        printk(KERN_INFO
3054                               "submit_bh(rw=0x%x FLUSH, bdev=%p)\n",
3055                               rw, bh->b_bdev);
3056                if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
3057                        if ((dev_state->state->print_mask &
3058                             (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3059                              BTRFSIC_PRINT_MASK_VERBOSE)))
3060                                printk(KERN_INFO
3061                                       "btrfsic_submit_bh(%s) with FLUSH"
3062                                       " but dummy block already in use"
3063                                       " (ignored)!\n",
3064                                       dev_state->name);
3065                } else {
3066                        struct btrfsic_block *const block =
3067                                &dev_state->dummy_block_for_bio_bh_flush;
3068
3069                        block->is_iodone = 0;
3070                        block->never_written = 0;
3071                        block->iodone_w_error = 0;
3072                        block->flush_gen = dev_state->last_flush_gen + 1;
3073                        block->submit_bio_bh_rw = rw;
3074                        block->orig_bio_bh_private = bh->b_private;
3075                        block->orig_bio_bh_end_io.bh = bh->b_end_io;
3076                        block->next_in_same_bio = NULL;
3077                        bh->b_private = block;
3078                        bh->b_end_io = btrfsic_bh_end_io;
3079                }
3080        }
3081        mutex_unlock(&btrfsic_mutex);
3082        return submit_bh(rw, bh);
3083}
3084
3085void btrfsic_submit_bio(int rw, struct bio *bio)
3086{
3087        struct btrfsic_dev_state *dev_state;
3088
3089        if (!btrfsic_is_initialized) {
3090                submit_bio(rw, bio);
3091                return;
3092        }
3093
3094        mutex_lock(&btrfsic_mutex);
3095        /* since btrfsic_submit_bio() is also called before
3096         * btrfsic_mount(), this might return NULL */
3097        dev_state = btrfsic_dev_state_lookup(bio->bi_bdev);
3098        if (NULL != dev_state &&
3099            (rw & WRITE) && NULL != bio->bi_io_vec) {
3100                unsigned int i;
3101                u64 dev_bytenr;
3102                int bio_is_patched;
3103                char **mapped_datav;
3104
3105                dev_bytenr = 512 * bio->bi_sector;
3106                bio_is_patched = 0;
3107                if (dev_state->state->print_mask &
3108                    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3109                        printk(KERN_INFO
3110                               "submit_bio(rw=0x%x, bi_vcnt=%u,"
3111                               " bi_sector=%lu (bytenr %llu), bi_bdev=%p)\n",
3112                               rw, bio->bi_vcnt, (unsigned long)bio->bi_sector,
3113                               (unsigned long long)dev_bytenr,
3114                               bio->bi_bdev);
3115
3116                mapped_datav = kmalloc(sizeof(*mapped_datav) * bio->bi_vcnt,
3117                                       GFP_NOFS);
3118                if (!mapped_datav)
3119                        goto leave;
3120                for (i = 0; i < bio->bi_vcnt; i++) {
3121                        BUG_ON(bio->bi_io_vec[i].bv_len != PAGE_CACHE_SIZE);
3122                        mapped_datav[i] = kmap(bio->bi_io_vec[i].bv_page);
3123                        if (!mapped_datav[i]) {
3124                                while (i > 0) {
3125                                        i--;
3126                                        kunmap(bio->bi_io_vec[i].bv_page);
3127                                }
3128                                kfree(mapped_datav);
3129                                goto leave;
3130                        }
3131                        if ((BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3132                             BTRFSIC_PRINT_MASK_VERBOSE) ==
3133                            (dev_state->state->print_mask &
3134                             (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3135                              BTRFSIC_PRINT_MASK_VERBOSE)))
3136                                printk(KERN_INFO
3137                                       "#%u: page=%p, len=%u, offset=%u\n",
3138                                       i, bio->bi_io_vec[i].bv_page,
3139                                       bio->bi_io_vec[i].bv_len,
3140                                       bio->bi_io_vec[i].bv_offset);
3141                }
3142                btrfsic_process_written_block(dev_state, dev_bytenr,
3143                                              mapped_datav, bio->bi_vcnt,
3144                                              bio, &bio_is_patched,
3145                                              NULL, rw);
3146                while (i > 0) {
3147                        i--;
3148                        kunmap(bio->bi_io_vec[i].bv_page);
3149                }
3150                kfree(mapped_datav);
3151        } else if (NULL != dev_state && (rw & REQ_FLUSH)) {
3152                if (dev_state->state->print_mask &
3153                    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3154                        printk(KERN_INFO
3155                               "submit_bio(rw=0x%x FLUSH, bdev=%p)\n",
3156                               rw, bio->bi_bdev);
3157                if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
3158                        if ((dev_state->state->print_mask &
3159                             (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3160                              BTRFSIC_PRINT_MASK_VERBOSE)))
3161                                printk(KERN_INFO
3162                                       "btrfsic_submit_bio(%s) with FLUSH"
3163                                       " but dummy block already in use"
3164                                       " (ignored)!\n",
3165                                       dev_state->name);
3166                } else {
3167                        struct btrfsic_block *const block =
3168                                &dev_state->dummy_block_for_bio_bh_flush;
3169
3170                        block->is_iodone = 0;
3171                        block->never_written = 0;
3172                        block->iodone_w_error = 0;
3173                        block->flush_gen = dev_state->last_flush_gen + 1;
3174                        block->submit_bio_bh_rw = rw;
3175                        block->orig_bio_bh_private = bio->bi_private;
3176                        block->orig_bio_bh_end_io.bio = bio->bi_end_io;
3177                        block->next_in_same_bio = NULL;
3178                        bio->bi_private = block;
3179                        bio->bi_end_io = btrfsic_bio_end_io;
3180                }
3181        }
3182leave:
3183        mutex_unlock(&btrfsic_mutex);
3184
3185        submit_bio(rw, bio);
3186}
3187
3188int btrfsic_mount(struct btrfs_root *root,
3189                  struct btrfs_fs_devices *fs_devices,
3190                  int including_extent_data, u32 print_mask)
3191{
3192        int ret;
3193        struct btrfsic_state *state;
3194        struct list_head *dev_head = &fs_devices->devices;
3195        struct btrfs_device *device;
3196
3197        if (root->nodesize != root->leafsize) {
3198                printk(KERN_INFO
3199                       "btrfsic: cannot handle nodesize %d != leafsize %d!\n",
3200                       root->nodesize, root->leafsize);
3201                return -1;
3202        }
3203        if (root->nodesize & ((u64)PAGE_CACHE_SIZE - 1)) {
3204                printk(KERN_INFO
3205                       "btrfsic: cannot handle nodesize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3206                       root->nodesize, (unsigned long)PAGE_CACHE_SIZE);
3207                return -1;
3208        }
3209        if (root->leafsize & ((u64)PAGE_CACHE_SIZE - 1)) {
3210                printk(KERN_INFO
3211                       "btrfsic: cannot handle leafsize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3212                       root->leafsize, (unsigned long)PAGE_CACHE_SIZE);
3213                return -1;
3214        }
3215        if (root->sectorsize & ((u64)PAGE_CACHE_SIZE - 1)) {
3216                printk(KERN_INFO
3217                       "btrfsic: cannot handle sectorsize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3218                       root->sectorsize, (unsigned long)PAGE_CACHE_SIZE);
3219                return -1;
3220        }
3221        state = kzalloc(sizeof(*state), GFP_NOFS);
3222        if (NULL == state) {
3223                printk(KERN_INFO "btrfs check-integrity: kmalloc() failed!\n");
3224                return -1;
3225        }
3226
3227        if (!btrfsic_is_initialized) {
3228                mutex_init(&btrfsic_mutex);
3229                btrfsic_dev_state_hashtable_init(&btrfsic_dev_state_hashtable);
3230                btrfsic_is_initialized = 1;
3231        }
3232        mutex_lock(&btrfsic_mutex);
3233        state->root = root;
3234        state->print_mask = print_mask;
3235        state->include_extent_data = including_extent_data;
3236        state->csum_size = 0;
3237        state->metablock_size = root->nodesize;
3238        state->datablock_size = root->sectorsize;
3239        INIT_LIST_HEAD(&state->all_blocks_list);
3240        btrfsic_block_hashtable_init(&state->block_hashtable);
3241        btrfsic_block_link_hashtable_init(&state->block_link_hashtable);
3242        state->max_superblock_generation = 0;
3243        state->latest_superblock = NULL;
3244
3245        list_for_each_entry(device, dev_head, dev_list) {
3246                struct btrfsic_dev_state *ds;
3247                char *p;
3248
3249                if (!device->bdev || !device->name)
3250                        continue;
3251
3252                ds = btrfsic_dev_state_alloc();
3253                if (NULL == ds) {
3254                        printk(KERN_INFO
3255                               "btrfs check-integrity: kmalloc() failed!\n");
3256                        mutex_unlock(&btrfsic_mutex);
3257                        return -1;
3258                }
3259                ds->bdev = device->bdev;
3260                ds->state = state;
3261                bdevname(ds->bdev, ds->name);
3262                ds->name[BDEVNAME_SIZE - 1] = '\0';
3263                for (p = ds->name; *p != '\0'; p++);
3264                while (p > ds->name && *p != '/')
3265                        p--;
3266                if (*p == '/')
3267                        p++;
3268                strlcpy(ds->name, p, sizeof(ds->name));
3269                btrfsic_dev_state_hashtable_add(ds,
3270                                                &btrfsic_dev_state_hashtable);
3271        }
3272
3273        ret = btrfsic_process_superblock(state, fs_devices);
3274        if (0 != ret) {
3275                mutex_unlock(&btrfsic_mutex);
3276                btrfsic_unmount(root, fs_devices);
3277                return ret;
3278        }
3279
3280        if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_DATABASE)
3281                btrfsic_dump_database(state);
3282        if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_TREE)
3283                btrfsic_dump_tree(state);
3284
3285        mutex_unlock(&btrfsic_mutex);
3286        return 0;
3287}
3288
3289void btrfsic_unmount(struct btrfs_root *root,
3290                     struct btrfs_fs_devices *fs_devices)
3291{
3292        struct list_head *elem_all;
3293        struct list_head *tmp_all;
3294        struct btrfsic_state *state;
3295        struct list_head *dev_head = &fs_devices->devices;
3296        struct btrfs_device *device;
3297
3298        if (!btrfsic_is_initialized)
3299                return;
3300
3301        mutex_lock(&btrfsic_mutex);
3302
3303        state = NULL;
3304        list_for_each_entry(device, dev_head, dev_list) {
3305                struct btrfsic_dev_state *ds;
3306
3307                if (!device->bdev || !device->name)
3308                        continue;
3309
3310                ds = btrfsic_dev_state_hashtable_lookup(
3311                                device->bdev,
3312                                &btrfsic_dev_state_hashtable);
3313                if (NULL != ds) {
3314                        state = ds->state;
3315                        btrfsic_dev_state_hashtable_remove(ds);
3316                        btrfsic_dev_state_free(ds);
3317                }
3318        }
3319
3320        if (NULL == state) {
3321                printk(KERN_INFO
3322                       "btrfsic: error, cannot find state information"
3323                       " on umount!\n");
3324                mutex_unlock(&btrfsic_mutex);
3325                return;
3326        }
3327
3328        /*
3329         * Don't care about keeping the lists' state up to date,
3330         * just free all memory that was allocated dynamically.
3331         * Free the blocks and the block_links.
3332         */
3333        list_for_each_safe(elem_all, tmp_all, &state->all_blocks_list) {
3334                struct btrfsic_block *const b_all =
3335                    list_entry(elem_all, struct btrfsic_block,
3336                               all_blocks_node);
3337                struct list_head *elem_ref_to;
3338                struct list_head *tmp_ref_to;
3339
3340                list_for_each_safe(elem_ref_to, tmp_ref_to,
3341                                   &b_all->ref_to_list) {
3342                        struct btrfsic_block_link *const l =
3343                            list_entry(elem_ref_to,
3344                                       struct btrfsic_block_link,
3345                                       node_ref_to);
3346
3347                        if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
3348                                btrfsic_print_rem_link(state, l);
3349
3350                        l->ref_cnt--;
3351                        if (0 == l->ref_cnt)
3352                                btrfsic_block_link_free(l);
3353                }
3354
3355                if (b_all->is_iodone || b_all->never_written)
3356                        btrfsic_block_free(b_all);
3357                else
3358                        printk(KERN_INFO "btrfs: attempt to free %c-block"
3359                               " @%llu (%s/%llu/%d) on umount which is"
3360                               " not yet iodone!\n",
3361                               btrfsic_get_block_type(state, b_all),
3362                               (unsigned long long)b_all->logical_bytenr,
3363                               b_all->dev_state->name,
3364                               (unsigned long long)b_all->dev_bytenr,
3365                               b_all->mirror_num);
3366        }
3367
3368        mutex_unlock(&btrfsic_mutex);
3369
3370        kfree(state);
3371}
3372
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