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 a FLUSH request to the device where
  41 *        these blocks are located was received and completed.
  42 *    2b. All referenced blocks need to have a generation
  43 *        number which is equal to the parent's number.
  44 *
  45 * One issue that was found using this module was that the log
  46 * tree on disk became temporarily corrupted because disk blocks
  47 * that had been in use for the log tree had been freed and
  48 * reused too early, while being referenced by the written super
  49 * block.
  50 *
  51 * The search term in the kernel log that can be used to filter
  52 * on the existence of detected integrity issues is
  53 * "btrfs: attempt".
  54 *
  55 * The integrity check is enabled via mount options. These
  56 * mount options are only supported if the integrity check
  57 * tool is compiled by defining BTRFS_FS_CHECK_INTEGRITY.
  58 *
  59 * Example #1, apply integrity checks to all metadata:
  60 * mount /dev/sdb1 /mnt -o check_int
  61 *
  62 * Example #2, apply integrity checks to all metadata and
  63 * to data extents:
  64 * mount /dev/sdb1 /mnt -o check_int_data
  65 *
  66 * Example #3, apply integrity checks to all metadata and dump
  67 * the tree that the super block references to kernel messages
  68 * each time after a super block was written:
  69 * mount /dev/sdb1 /mnt -o check_int,check_int_print_mask=263
  70 *
  71 * If the integrity check tool is included and activated in
  72 * the mount options, plenty of kernel memory is used, and
  73 * plenty of additional CPU cycles are spent. Enabling this
  74 * functionality is not intended for normal use. In most
  75 * cases, unless you are a btrfs developer who needs to verify
  76 * the integrity of (super)-block write requests, do not
  77 * enable the config option BTRFS_FS_CHECK_INTEGRITY to
  78 * include and compile the integrity check tool.
  79 */
  80
  81#include <linux/sched.h>
  82#include <linux/slab.h>
  83#include <linux/buffer_head.h>
  84#include <linux/mutex.h>
  85#include <linux/crc32c.h>
  86#include <linux/genhd.h>
  87#include <linux/blkdev.h>
  88#include "ctree.h"
  89#include "disk-io.h"
  90#include "transaction.h"
  91#include "extent_io.h"
  92#include "volumes.h"
  93#include "print-tree.h"
  94#include "locking.h"
  95#include "check-integrity.h"
  96#include "rcu-string.h"
  97
  98#define BTRFSIC_BLOCK_HASHTABLE_SIZE 0x10000
  99#define BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE 0x10000
 100#define BTRFSIC_DEV2STATE_HASHTABLE_SIZE 0x100
 101#define BTRFSIC_BLOCK_MAGIC_NUMBER 0x14491051
 102#define BTRFSIC_BLOCK_LINK_MAGIC_NUMBER 0x11070807
 103#define BTRFSIC_DEV2STATE_MAGIC_NUMBER 0x20111530
 104#define BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER 20111300
 105#define BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL (200 - 6)    /* in characters,
 106                                                         * excluding " [...]" */
 107#define BTRFSIC_GENERATION_UNKNOWN ((u64)-1)
 108
 109/*
 110 * The definition of the bitmask fields for the print_mask.
 111 * They are specified with the mount option check_integrity_print_mask.
 112 */
 113#define BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE                     0x00000001
 114#define BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION         0x00000002
 115#define BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE                  0x00000004
 116#define BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE                 0x00000008
 117#define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH                        0x00000010
 118#define BTRFSIC_PRINT_MASK_END_IO_BIO_BH                        0x00000020
 119#define BTRFSIC_PRINT_MASK_VERBOSE                              0x00000040
 120#define BTRFSIC_PRINT_MASK_VERY_VERBOSE                         0x00000080
 121#define BTRFSIC_PRINT_MASK_INITIAL_TREE                         0x00000100
 122#define BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES                    0x00000200
 123#define BTRFSIC_PRINT_MASK_INITIAL_DATABASE                     0x00000400
 124#define BTRFSIC_PRINT_MASK_NUM_COPIES                           0x00000800
 125#define BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS                0x00001000
 126
 127struct btrfsic_dev_state;
 128struct btrfsic_state;
 129
 130struct btrfsic_block {
 131        u32 magic_num;          /* only used for debug purposes */
 132        unsigned int is_metadata:1;     /* if it is meta-data, not data-data */
 133        unsigned int is_superblock:1;   /* if it is one of the superblocks */
 134        unsigned int is_iodone:1;       /* if is done by lower subsystem */
 135        unsigned int iodone_w_error:1;  /* error was indicated to endio */
 136        unsigned int never_written:1;   /* block was added because it was
 137                                         * referenced, not because it was
 138                                         * written */
 139        unsigned int mirror_num:2;      /* large enough to hold
 140                                         * BTRFS_SUPER_MIRROR_MAX */
 141        struct btrfsic_dev_state *dev_state;
 142        u64 dev_bytenr;         /* key, physical byte num on disk */
 143        u64 logical_bytenr;     /* logical byte num on disk */
 144        u64 generation;
 145        struct btrfs_disk_key disk_key; /* extra info to print in case of
 146                                         * issues, will not always be correct */
 147        struct list_head collision_resolving_node;      /* list node */
 148        struct list_head all_blocks_node;       /* list node */
 149
 150        /* the following two lists contain block_link items */
 151        struct list_head ref_to_list;   /* list */
 152        struct list_head ref_from_list; /* list */
 153        struct btrfsic_block *next_in_same_bio;
 154        void *orig_bio_bh_private;
 155        union {
 156                bio_end_io_t *bio;
 157                bh_end_io_t *bh;
 158        } orig_bio_bh_end_io;
 159        int submit_bio_bh_rw;
 160        u64 flush_gen; /* only valid if !never_written */
 161};
 162
 163/*
 164 * Elements of this type are allocated dynamically and required because
 165 * each block object can refer to and can be ref from multiple blocks.
 166 * The key to lookup them in the hashtable is the dev_bytenr of
 167 * the block ref to plus the one from the block refered from.
 168 * The fact that they are searchable via a hashtable and that a
 169 * ref_cnt is maintained is not required for the btrfs integrity
 170 * check algorithm itself, it is only used to make the output more
 171 * beautiful in case that an error is detected (an error is defined
 172 * as a write operation to a block while that block is still referenced).
 173 */
 174struct btrfsic_block_link {
 175        u32 magic_num;          /* only used for debug purposes */
 176        u32 ref_cnt;
 177        struct list_head node_ref_to;   /* list node */
 178        struct list_head node_ref_from; /* list node */
 179        struct list_head collision_resolving_node;      /* list node */
 180        struct btrfsic_block *block_ref_to;
 181        struct btrfsic_block *block_ref_from;
 182        u64 parent_generation;
 183};
 184
 185struct btrfsic_dev_state {
 186        u32 magic_num;          /* only used for debug purposes */
 187        struct block_device *bdev;
 188        struct btrfsic_state *state;
 189        struct list_head collision_resolving_node;      /* list node */
 190        struct btrfsic_block dummy_block_for_bio_bh_flush;
 191        u64 last_flush_gen;
 192        char name[BDEVNAME_SIZE];
 193};
 194
 195struct btrfsic_block_hashtable {
 196        struct list_head table[BTRFSIC_BLOCK_HASHTABLE_SIZE];
 197};
 198
 199struct btrfsic_block_link_hashtable {
 200        struct list_head table[BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE];
 201};
 202
 203struct btrfsic_dev_state_hashtable {
 204        struct list_head table[BTRFSIC_DEV2STATE_HASHTABLE_SIZE];
 205};
 206
 207struct btrfsic_block_data_ctx {
 208        u64 start;              /* virtual bytenr */
 209        u64 dev_bytenr;         /* physical bytenr on device */
 210        u32 len;
 211        struct btrfsic_dev_state *dev;
 212        char **datav;
 213        struct page **pagev;
 214        void *mem_to_free;
 215};
 216
 217/* This structure is used to implement recursion without occupying
 218 * any stack space, refer to btrfsic_process_metablock() */
 219struct btrfsic_stack_frame {
 220        u32 magic;
 221        u32 nr;
 222        int error;
 223        int i;
 224        int limit_nesting;
 225        int num_copies;
 226        int mirror_num;
 227        struct btrfsic_block *block;
 228        struct btrfsic_block_data_ctx *block_ctx;
 229        struct btrfsic_block *next_block;
 230        struct btrfsic_block_data_ctx next_block_ctx;
 231        struct btrfs_header *hdr;
 232        struct btrfsic_stack_frame *prev;
 233};
 234
 235/* Some state per mounted filesystem */
 236struct btrfsic_state {
 237        u32 print_mask;
 238        int include_extent_data;
 239        int csum_size;
 240        struct list_head all_blocks_list;
 241        struct btrfsic_block_hashtable block_hashtable;
 242        struct btrfsic_block_link_hashtable block_link_hashtable;
 243        struct btrfs_root *root;
 244        u64 max_superblock_generation;
 245        struct btrfsic_block *latest_superblock;
 246        u32 metablock_size;
 247        u32 datablock_size;
 248};
 249
 250static void btrfsic_block_init(struct btrfsic_block *b);
 251static struct btrfsic_block *btrfsic_block_alloc(void);
 252static void btrfsic_block_free(struct btrfsic_block *b);
 253static void btrfsic_block_link_init(struct btrfsic_block_link *n);
 254static struct btrfsic_block_link *btrfsic_block_link_alloc(void);
 255static void btrfsic_block_link_free(struct btrfsic_block_link *n);
 256static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds);
 257static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void);
 258static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds);
 259static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h);
 260static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
 261                                        struct btrfsic_block_hashtable *h);
 262static void btrfsic_block_hashtable_remove(struct btrfsic_block *b);
 263static struct btrfsic_block *btrfsic_block_hashtable_lookup(
 264                struct block_device *bdev,
 265                u64 dev_bytenr,
 266                struct btrfsic_block_hashtable *h);
 267static void btrfsic_block_link_hashtable_init(
 268                struct btrfsic_block_link_hashtable *h);
 269static void btrfsic_block_link_hashtable_add(
 270                struct btrfsic_block_link *l,
 271                struct btrfsic_block_link_hashtable *h);
 272static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l);
 273static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
 274                struct block_device *bdev_ref_to,
 275                u64 dev_bytenr_ref_to,
 276                struct block_device *bdev_ref_from,
 277                u64 dev_bytenr_ref_from,
 278                struct btrfsic_block_link_hashtable *h);
 279static void btrfsic_dev_state_hashtable_init(
 280                struct btrfsic_dev_state_hashtable *h);
 281static void btrfsic_dev_state_hashtable_add(
 282                struct btrfsic_dev_state *ds,
 283                struct btrfsic_dev_state_hashtable *h);
 284static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds);
 285static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
 286                struct block_device *bdev,
 287                struct btrfsic_dev_state_hashtable *h);
 288static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void);
 289static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf);
 290static int btrfsic_process_superblock(struct btrfsic_state *state,
 291                                      struct btrfs_fs_devices *fs_devices);
 292static int btrfsic_process_metablock(struct btrfsic_state *state,
 293                                     struct btrfsic_block *block,
 294                                     struct btrfsic_block_data_ctx *block_ctx,
 295                                     int limit_nesting, int force_iodone_flag);
 296static void btrfsic_read_from_block_data(
 297        struct btrfsic_block_data_ctx *block_ctx,
 298        void *dst, u32 offset, size_t len);
 299static int btrfsic_create_link_to_next_block(
 300                struct btrfsic_state *state,
 301                struct btrfsic_block *block,
 302                struct btrfsic_block_data_ctx
 303                *block_ctx, u64 next_bytenr,
 304                int limit_nesting,
 305                struct btrfsic_block_data_ctx *next_block_ctx,
 306                struct btrfsic_block **next_blockp,
 307                int force_iodone_flag,
 308                int *num_copiesp, int *mirror_nump,
 309                struct btrfs_disk_key *disk_key,
 310                u64 parent_generation);
 311static int btrfsic_handle_extent_data(struct btrfsic_state *state,
 312                                      struct btrfsic_block *block,
 313                                      struct btrfsic_block_data_ctx *block_ctx,
 314                                      u32 item_offset, int force_iodone_flag);
 315static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
 316                             struct btrfsic_block_data_ctx *block_ctx_out,
 317                             int mirror_num);
 318static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
 319                                  u32 len, struct block_device *bdev,
 320                                  struct btrfsic_block_data_ctx *block_ctx_out);
 321static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx);
 322static int btrfsic_read_block(struct btrfsic_state *state,
 323                              struct btrfsic_block_data_ctx *block_ctx);
 324static void btrfsic_dump_database(struct btrfsic_state *state);
 325static void btrfsic_complete_bio_end_io(struct bio *bio, int err);
 326static int btrfsic_test_for_metadata(struct btrfsic_state *state,
 327                                     char **datav, unsigned int num_pages);
 328static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
 329                                          u64 dev_bytenr, char **mapped_datav,
 330                                          unsigned int num_pages,
 331                                          struct bio *bio, int *bio_is_patched,
 332                                          struct buffer_head *bh,
 333                                          int submit_bio_bh_rw);
 334static int btrfsic_process_written_superblock(
 335                struct btrfsic_state *state,
 336                struct btrfsic_block *const block,
 337                struct btrfs_super_block *const super_hdr);
 338static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status);
 339static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate);
 340static int btrfsic_is_block_ref_by_superblock(const struct btrfsic_state *state,
 341                                              const struct btrfsic_block *block,
 342                                              int recursion_level);
 343static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
 344                                        struct btrfsic_block *const block,
 345                                        int recursion_level);
 346static void btrfsic_print_add_link(const struct btrfsic_state *state,
 347                                   const struct btrfsic_block_link *l);
 348static void btrfsic_print_rem_link(const struct btrfsic_state *state,
 349                                   const struct btrfsic_block_link *l);
 350static char btrfsic_get_block_type(const struct btrfsic_state *state,
 351                                   const struct btrfsic_block *block);
 352static void btrfsic_dump_tree(const struct btrfsic_state *state);
 353static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
 354                                  const struct btrfsic_block *block,
 355                                  int indent_level);
 356static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
 357                struct btrfsic_state *state,
 358                struct btrfsic_block_data_ctx *next_block_ctx,
 359                struct btrfsic_block *next_block,
 360                struct btrfsic_block *from_block,
 361                u64 parent_generation);
 362static struct btrfsic_block *btrfsic_block_lookup_or_add(
 363                struct btrfsic_state *state,
 364                struct btrfsic_block_data_ctx *block_ctx,
 365                const char *additional_string,
 366                int is_metadata,
 367                int is_iodone,
 368                int never_written,
 369                int mirror_num,
 370                int *was_created);
 371static int btrfsic_process_superblock_dev_mirror(
 372                struct btrfsic_state *state,
 373                struct btrfsic_dev_state *dev_state,
 374                struct btrfs_device *device,
 375                int superblock_mirror_num,
 376                struct btrfsic_dev_state **selected_dev_state,
 377                struct btrfs_super_block *selected_super);
 378static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
 379                struct block_device *bdev);
 380static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
 381                                           u64 bytenr,
 382                                           struct btrfsic_dev_state *dev_state,
 383                                           u64 dev_bytenr);
 384
 385static struct mutex btrfsic_mutex;
 386static int btrfsic_is_initialized;
 387static struct btrfsic_dev_state_hashtable btrfsic_dev_state_hashtable;
 388
 389
 390static void btrfsic_block_init(struct btrfsic_block *b)
 391{
 392        b->magic_num = BTRFSIC_BLOCK_MAGIC_NUMBER;
 393        b->dev_state = NULL;
 394        b->dev_bytenr = 0;
 395        b->logical_bytenr = 0;
 396        b->generation = BTRFSIC_GENERATION_UNKNOWN;
 397        b->disk_key.objectid = 0;
 398        b->disk_key.type = 0;
 399        b->disk_key.offset = 0;
 400        b->is_metadata = 0;
 401        b->is_superblock = 0;
 402        b->is_iodone = 0;
 403        b->iodone_w_error = 0;
 404        b->never_written = 0;
 405        b->mirror_num = 0;
 406        b->next_in_same_bio = NULL;
 407        b->orig_bio_bh_private = NULL;
 408        b->orig_bio_bh_end_io.bio = NULL;
 409        INIT_LIST_HEAD(&b->collision_resolving_node);
 410        INIT_LIST_HEAD(&b->all_blocks_node);
 411        INIT_LIST_HEAD(&b->ref_to_list);
 412        INIT_LIST_HEAD(&b->ref_from_list);
 413        b->submit_bio_bh_rw = 0;
 414        b->flush_gen = 0;
 415}
 416
 417static struct btrfsic_block *btrfsic_block_alloc(void)
 418{
 419        struct btrfsic_block *b;
 420
 421        b = kzalloc(sizeof(*b), GFP_NOFS);
 422        if (NULL != b)
 423                btrfsic_block_init(b);
 424
 425        return b;
 426}
 427
 428static void btrfsic_block_free(struct btrfsic_block *b)
 429{
 430        BUG_ON(!(NULL == b || BTRFSIC_BLOCK_MAGIC_NUMBER == b->magic_num));
 431        kfree(b);
 432}
 433
 434static void btrfsic_block_link_init(struct btrfsic_block_link *l)
 435{
 436        l->magic_num = BTRFSIC_BLOCK_LINK_MAGIC_NUMBER;
 437        l->ref_cnt = 1;
 438        INIT_LIST_HEAD(&l->node_ref_to);
 439        INIT_LIST_HEAD(&l->node_ref_from);
 440        INIT_LIST_HEAD(&l->collision_resolving_node);
 441        l->block_ref_to = NULL;
 442        l->block_ref_from = NULL;
 443}
 444
 445static struct btrfsic_block_link *btrfsic_block_link_alloc(void)
 446{
 447        struct btrfsic_block_link *l;
 448
 449        l = kzalloc(sizeof(*l), GFP_NOFS);
 450        if (NULL != l)
 451                btrfsic_block_link_init(l);
 452
 453        return l;
 454}
 455
 456static void btrfsic_block_link_free(struct btrfsic_block_link *l)
 457{
 458        BUG_ON(!(NULL == l || BTRFSIC_BLOCK_LINK_MAGIC_NUMBER == l->magic_num));
 459        kfree(l);
 460}
 461
 462static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds)
 463{
 464        ds->magic_num = BTRFSIC_DEV2STATE_MAGIC_NUMBER;
 465        ds->bdev = NULL;
 466        ds->state = NULL;
 467        ds->name[0] = '\0';
 468        INIT_LIST_HEAD(&ds->collision_resolving_node);
 469        ds->last_flush_gen = 0;
 470        btrfsic_block_init(&ds->dummy_block_for_bio_bh_flush);
 471        ds->dummy_block_for_bio_bh_flush.is_iodone = 1;
 472        ds->dummy_block_for_bio_bh_flush.dev_state = ds;
 473}
 474
 475static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void)
 476{
 477        struct btrfsic_dev_state *ds;
 478
 479        ds = kzalloc(sizeof(*ds), GFP_NOFS);
 480        if (NULL != ds)
 481                btrfsic_dev_state_init(ds);
 482
 483        return ds;
 484}
 485
 486static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds)
 487{
 488        BUG_ON(!(NULL == ds ||
 489                 BTRFSIC_DEV2STATE_MAGIC_NUMBER == ds->magic_num));
 490        kfree(ds);
 491}
 492
 493static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h)
 494{
 495        int i;
 496
 497        for (i = 0; i < BTRFSIC_BLOCK_HASHTABLE_SIZE; i++)
 498                INIT_LIST_HEAD(h->table + i);
 499}
 500
 501static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
 502                                        struct btrfsic_block_hashtable *h)
 503{
 504        const unsigned int hashval =
 505            (((unsigned int)(b->dev_bytenr >> 16)) ^
 506             ((unsigned int)((uintptr_t)b->dev_state->bdev))) &
 507             (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
 508
 509        list_add(&b->collision_resolving_node, h->table + hashval);
 510}
 511
 512static void btrfsic_block_hashtable_remove(struct btrfsic_block *b)
 513{
 514        list_del(&b->collision_resolving_node);
 515}
 516
 517static struct btrfsic_block *btrfsic_block_hashtable_lookup(
 518                struct block_device *bdev,
 519                u64 dev_bytenr,
 520                struct btrfsic_block_hashtable *h)
 521{
 522        const unsigned int hashval =
 523            (((unsigned int)(dev_bytenr >> 16)) ^
 524             ((unsigned int)((uintptr_t)bdev))) &
 525             (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
 526        struct list_head *elem;
 527
 528        list_for_each(elem, h->table + hashval) {
 529                struct btrfsic_block *const b =
 530                    list_entry(elem, struct btrfsic_block,
 531                               collision_resolving_node);
 532
 533                if (b->dev_state->bdev == bdev && b->dev_bytenr == dev_bytenr)
 534                        return b;
 535        }
 536
 537        return NULL;
 538}
 539
 540static void btrfsic_block_link_hashtable_init(
 541                struct btrfsic_block_link_hashtable *h)
 542{
 543        int i;
 544
 545        for (i = 0; i < BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE; i++)
 546                INIT_LIST_HEAD(h->table + i);
 547}
 548
 549static void btrfsic_block_link_hashtable_add(
 550                struct btrfsic_block_link *l,
 551                struct btrfsic_block_link_hashtable *h)
 552{
 553        const unsigned int hashval =
 554            (((unsigned int)(l->block_ref_to->dev_bytenr >> 16)) ^
 555             ((unsigned int)(l->block_ref_from->dev_bytenr >> 16)) ^
 556             ((unsigned int)((uintptr_t)l->block_ref_to->dev_state->bdev)) ^
 557             ((unsigned int)((uintptr_t)l->block_ref_from->dev_state->bdev)))
 558             & (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
 559
 560        BUG_ON(NULL == l->block_ref_to);
 561        BUG_ON(NULL == l->block_ref_from);
 562        list_add(&l->collision_resolving_node, h->table + hashval);
 563}
 564
 565static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l)
 566{
 567        list_del(&l->collision_resolving_node);
 568}
 569
 570static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
 571                struct block_device *bdev_ref_to,
 572                u64 dev_bytenr_ref_to,
 573                struct block_device *bdev_ref_from,
 574                u64 dev_bytenr_ref_from,
 575                struct btrfsic_block_link_hashtable *h)
 576{
 577        const unsigned int hashval =
 578            (((unsigned int)(dev_bytenr_ref_to >> 16)) ^
 579             ((unsigned int)(dev_bytenr_ref_from >> 16)) ^
 580             ((unsigned int)((uintptr_t)bdev_ref_to)) ^
 581             ((unsigned int)((uintptr_t)bdev_ref_from))) &
 582             (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
 583        struct list_head *elem;
 584
 585        list_for_each(elem, h->table + hashval) {
 586                struct btrfsic_block_link *const l =
 587                    list_entry(elem, struct btrfsic_block_link,
 588                               collision_resolving_node);
 589
 590                BUG_ON(NULL == l->block_ref_to);
 591                BUG_ON(NULL == l->block_ref_from);
 592                if (l->block_ref_to->dev_state->bdev == bdev_ref_to &&
 593                    l->block_ref_to->dev_bytenr == dev_bytenr_ref_to &&
 594                    l->block_ref_from->dev_state->bdev == bdev_ref_from &&
 595                    l->block_ref_from->dev_bytenr == dev_bytenr_ref_from)
 596                        return l;
 597        }
 598
 599        return NULL;
 600}
 601
 602static void btrfsic_dev_state_hashtable_init(
 603                struct btrfsic_dev_state_hashtable *h)
 604{
 605        int i;
 606
 607        for (i = 0; i < BTRFSIC_DEV2STATE_HASHTABLE_SIZE; i++)
 608                INIT_LIST_HEAD(h->table + i);
 609}
 610
 611static void btrfsic_dev_state_hashtable_add(
 612                struct btrfsic_dev_state *ds,
 613                struct btrfsic_dev_state_hashtable *h)
 614{
 615        const unsigned int hashval =
 616            (((unsigned int)((uintptr_t)ds->bdev)) &
 617             (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
 618
 619        list_add(&ds->collision_resolving_node, h->table + hashval);
 620}
 621
 622static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds)
 623{
 624        list_del(&ds->collision_resolving_node);
 625}
 626
 627static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
 628                struct block_device *bdev,
 629                struct btrfsic_dev_state_hashtable *h)
 630{
 631        const unsigned int hashval =
 632            (((unsigned int)((uintptr_t)bdev)) &
 633             (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
 634        struct list_head *elem;
 635
 636        list_for_each(elem, h->table + hashval) {
 637                struct btrfsic_dev_state *const ds =
 638                    list_entry(elem, struct btrfsic_dev_state,
 639                               collision_resolving_node);
 640
 641                if (ds->bdev == bdev)
 642                        return ds;
 643        }
 644
 645        return NULL;
 646}
 647
 648static int btrfsic_process_superblock(struct btrfsic_state *state,
 649                                      struct btrfs_fs_devices *fs_devices)
 650{
 651        int ret = 0;
 652        struct btrfs_super_block *selected_super;
 653        struct list_head *dev_head = &fs_devices->devices;
 654        struct btrfs_device *device;
 655        struct btrfsic_dev_state *selected_dev_state = NULL;
 656        int pass;
 657
 658        BUG_ON(NULL == state);
 659        selected_super = kzalloc(sizeof(*selected_super), GFP_NOFS);
 660        if (NULL == selected_super) {
 661                printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
 662                return -1;
 663        }
 664
 665        list_for_each_entry(device, dev_head, dev_list) {
 666                int i;
 667                struct btrfsic_dev_state *dev_state;
 668
 669                if (!device->bdev || !device->name)
 670                        continue;
 671
 672                dev_state = btrfsic_dev_state_lookup(device->bdev);
 673                BUG_ON(NULL == dev_state);
 674                for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 675                        ret = btrfsic_process_superblock_dev_mirror(
 676                                        state, dev_state, device, i,
 677                                        &selected_dev_state, selected_super);
 678                        if (0 != ret && 0 == i) {
 679                                kfree(selected_super);
 680                                return ret;
 681                        }
 682                }
 683        }
 684
 685        if (NULL == state->latest_superblock) {
 686                printk(KERN_INFO "btrfsic: no superblock found!\n");
 687                kfree(selected_super);
 688                return -1;
 689        }
 690
 691        state->csum_size = btrfs_super_csum_size(selected_super);
 692
 693        for (pass = 0; pass < 3; pass++) {
 694                int num_copies;
 695                int mirror_num;
 696                u64 next_bytenr;
 697
 698                switch (pass) {
 699                case 0:
 700                        next_bytenr = btrfs_super_root(selected_super);
 701                        if (state->print_mask &
 702                            BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 703                                printk(KERN_INFO "root@%llu\n",
 704                                       (unsigned long long)next_bytenr);
 705                        break;
 706                case 1:
 707                        next_bytenr = btrfs_super_chunk_root(selected_super);
 708                        if (state->print_mask &
 709                            BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 710                                printk(KERN_INFO "chunk@%llu\n",
 711                                       (unsigned long long)next_bytenr);
 712                        break;
 713                case 2:
 714                        next_bytenr = btrfs_super_log_root(selected_super);
 715                        if (0 == next_bytenr)
 716                                continue;
 717                        if (state->print_mask &
 718                            BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 719                                printk(KERN_INFO "log@%llu\n",
 720                                       (unsigned long long)next_bytenr);
 721                        break;
 722                }
 723
 724                num_copies =
 725                    btrfs_num_copies(&state->root->fs_info->mapping_tree,
 726                                     next_bytenr, state->metablock_size);
 727                if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 728                        printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
 729                               (unsigned long long)next_bytenr, num_copies);
 730
 731                for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 732                        struct btrfsic_block *next_block;
 733                        struct btrfsic_block_data_ctx tmp_next_block_ctx;
 734                        struct btrfsic_block_link *l;
 735
 736                        ret = btrfsic_map_block(state, next_bytenr,
 737                                                state->metablock_size,
 738                                                &tmp_next_block_ctx,
 739                                                mirror_num);
 740                        if (ret) {
 741                                printk(KERN_INFO "btrfsic:"
 742                                       " btrfsic_map_block(root @%llu,"
 743                                       " mirror %d) failed!\n",
 744                                       (unsigned long long)next_bytenr,
 745                                       mirror_num);
 746                                kfree(selected_super);
 747                                return -1;
 748                        }
 749
 750                        next_block = btrfsic_block_hashtable_lookup(
 751                                        tmp_next_block_ctx.dev->bdev,
 752                                        tmp_next_block_ctx.dev_bytenr,
 753                                        &state->block_hashtable);
 754                        BUG_ON(NULL == next_block);
 755
 756                        l = btrfsic_block_link_hashtable_lookup(
 757                                        tmp_next_block_ctx.dev->bdev,
 758                                        tmp_next_block_ctx.dev_bytenr,
 759                                        state->latest_superblock->dev_state->
 760                                        bdev,
 761                                        state->latest_superblock->dev_bytenr,
 762                                        &state->block_link_hashtable);
 763                        BUG_ON(NULL == l);
 764
 765                        ret = btrfsic_read_block(state, &tmp_next_block_ctx);
 766                        if (ret < (int)PAGE_CACHE_SIZE) {
 767                                printk(KERN_INFO
 768                                       "btrfsic: read @logical %llu failed!\n",
 769                                       (unsigned long long)
 770                                       tmp_next_block_ctx.start);
 771                                btrfsic_release_block_ctx(&tmp_next_block_ctx);
 772                                kfree(selected_super);
 773                                return -1;
 774                        }
 775
 776                        ret = btrfsic_process_metablock(state,
 777                                                        next_block,
 778                                                        &tmp_next_block_ctx,
 779                                                        BTRFS_MAX_LEVEL + 3, 1);
 780                        btrfsic_release_block_ctx(&tmp_next_block_ctx);
 781                }
 782        }
 783
 784        kfree(selected_super);
 785        return ret;
 786}
 787
 788static int btrfsic_process_superblock_dev_mirror(
 789                struct btrfsic_state *state,
 790                struct btrfsic_dev_state *dev_state,
 791                struct btrfs_device *device,
 792                int superblock_mirror_num,
 793                struct btrfsic_dev_state **selected_dev_state,
 794                struct btrfs_super_block *selected_super)
 795{
 796        struct btrfs_super_block *super_tmp;
 797        u64 dev_bytenr;
 798        struct buffer_head *bh;
 799        struct btrfsic_block *superblock_tmp;
 800        int pass;
 801        struct block_device *const superblock_bdev = device->bdev;
 802
 803        /* super block bytenr is always the unmapped device bytenr */
 804        dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
 805        if (dev_bytenr + BTRFS_SUPER_INFO_SIZE > device->total_bytes)
 806                return -1;
 807        bh = __bread(superblock_bdev, dev_bytenr / 4096,
 808                     BTRFS_SUPER_INFO_SIZE);
 809        if (NULL == bh)
 810                return -1;
 811        super_tmp = (struct btrfs_super_block *)
 812            (bh->b_data + (dev_bytenr & 4095));
 813
 814        if (btrfs_super_bytenr(super_tmp) != dev_bytenr ||
 815            strncmp((char *)(&(super_tmp->magic)), BTRFS_MAGIC,
 816                    sizeof(super_tmp->magic)) ||
 817            memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE) ||
 818            btrfs_super_nodesize(super_tmp) != state->metablock_size ||
 819            btrfs_super_leafsize(super_tmp) != state->metablock_size ||
 820            btrfs_super_sectorsize(super_tmp) != state->datablock_size) {
 821                brelse(bh);
 822                return 0;
 823        }
 824
 825        superblock_tmp =
 826            btrfsic_block_hashtable_lookup(superblock_bdev,
 827                                           dev_bytenr,
 828                                           &state->block_hashtable);
 829        if (NULL == superblock_tmp) {
 830                superblock_tmp = btrfsic_block_alloc();
 831                if (NULL == superblock_tmp) {
 832                        printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
 833                        brelse(bh);
 834                        return -1;
 835                }
 836                /* for superblock, only the dev_bytenr makes sense */
 837                superblock_tmp->dev_bytenr = dev_bytenr;
 838                superblock_tmp->dev_state = dev_state;
 839                superblock_tmp->logical_bytenr = dev_bytenr;
 840                superblock_tmp->generation = btrfs_super_generation(super_tmp);
 841                superblock_tmp->is_metadata = 1;
 842                superblock_tmp->is_superblock = 1;
 843                superblock_tmp->is_iodone = 1;
 844                superblock_tmp->never_written = 0;
 845                superblock_tmp->mirror_num = 1 + superblock_mirror_num;
 846                if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
 847                        printk_in_rcu(KERN_INFO "New initial S-block (bdev %p, %s)"
 848                                     " @%llu (%s/%llu/%d)\n",
 849                                     superblock_bdev,
 850                                     rcu_str_deref(device->name),
 851                                     (unsigned long long)dev_bytenr,
 852                                     dev_state->name,
 853                                     (unsigned long long)dev_bytenr,
 854                                     superblock_mirror_num);
 855                list_add(&superblock_tmp->all_blocks_node,
 856                         &state->all_blocks_list);
 857                btrfsic_block_hashtable_add(superblock_tmp,
 858                                            &state->block_hashtable);
 859        }
 860
 861        /* select the one with the highest generation field */
 862        if (btrfs_super_generation(super_tmp) >
 863            state->max_superblock_generation ||
 864            0 == state->max_superblock_generation) {
 865                memcpy(selected_super, super_tmp, sizeof(*selected_super));
 866                *selected_dev_state = dev_state;
 867                state->max_superblock_generation =
 868                    btrfs_super_generation(super_tmp);
 869                state->latest_superblock = superblock_tmp;
 870        }
 871
 872        for (pass = 0; pass < 3; pass++) {
 873                u64 next_bytenr;
 874                int num_copies;
 875                int mirror_num;
 876                const char *additional_string = NULL;
 877                struct btrfs_disk_key tmp_disk_key;
 878
 879                tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
 880                tmp_disk_key.offset = 0;
 881                switch (pass) {
 882                case 0:
 883                        tmp_disk_key.objectid =
 884                            cpu_to_le64(BTRFS_ROOT_TREE_OBJECTID);
 885                        additional_string = "initial root ";
 886                        next_bytenr = btrfs_super_root(super_tmp);
 887                        break;
 888                case 1:
 889                        tmp_disk_key.objectid =
 890                            cpu_to_le64(BTRFS_CHUNK_TREE_OBJECTID);
 891                        additional_string = "initial chunk ";
 892                        next_bytenr = btrfs_super_chunk_root(super_tmp);
 893                        break;
 894                case 2:
 895                        tmp_disk_key.objectid =
 896                            cpu_to_le64(BTRFS_TREE_LOG_OBJECTID);
 897                        additional_string = "initial log ";
 898                        next_bytenr = btrfs_super_log_root(super_tmp);
 899                        if (0 == next_bytenr)
 900                                continue;
 901                        break;
 902                }
 903
 904                num_copies =
 905                    btrfs_num_copies(&state->root->fs_info->mapping_tree,
 906                                     next_bytenr, state->metablock_size);
 907                if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 908                        printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
 909                               (unsigned long long)next_bytenr, num_copies);
 910                for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 911                        struct btrfsic_block *next_block;
 912                        struct btrfsic_block_data_ctx tmp_next_block_ctx;
 913                        struct btrfsic_block_link *l;
 914
 915                        if (btrfsic_map_block(state, next_bytenr,
 916                                              state->metablock_size,
 917                                              &tmp_next_block_ctx,
 918                                              mirror_num)) {
 919                                printk(KERN_INFO "btrfsic: btrfsic_map_block("
 920                                       "bytenr @%llu, mirror %d) failed!\n",
 921                                       (unsigned long long)next_bytenr,
 922                                       mirror_num);
 923                                brelse(bh);
 924                                return -1;
 925                        }
 926
 927                        next_block = btrfsic_block_lookup_or_add(
 928                                        state, &tmp_next_block_ctx,
 929                                        additional_string, 1, 1, 0,
 930                                        mirror_num, NULL);
 931                        if (NULL == next_block) {
 932                                btrfsic_release_block_ctx(&tmp_next_block_ctx);
 933                                brelse(bh);
 934                                return -1;
 935                        }
 936
 937                        next_block->disk_key = tmp_disk_key;
 938                        next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
 939                        l = btrfsic_block_link_lookup_or_add(
 940                                        state, &tmp_next_block_ctx,
 941                                        next_block, superblock_tmp,
 942                                        BTRFSIC_GENERATION_UNKNOWN);
 943                        btrfsic_release_block_ctx(&tmp_next_block_ctx);
 944                        if (NULL == l) {
 945                                brelse(bh);
 946                                return -1;
 947                        }
 948                }
 949        }
 950        if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES)
 951                btrfsic_dump_tree_sub(state, superblock_tmp, 0);
 952
 953        brelse(bh);
 954        return 0;
 955}
 956
 957static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void)
 958{
 959        struct btrfsic_stack_frame *sf;
 960
 961        sf = kzalloc(sizeof(*sf), GFP_NOFS);
 962        if (NULL == sf)
 963                printk(KERN_INFO "btrfsic: alloc memory failed!\n");
 964        else
 965                sf->magic = BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER;
 966        return sf;
 967}
 968
 969static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf)
 970{
 971        BUG_ON(!(NULL == sf ||
 972                 BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER == sf->magic));
 973        kfree(sf);
 974}
 975
 976static int btrfsic_process_metablock(
 977                struct btrfsic_state *state,
 978                struct btrfsic_block *const first_block,
 979                struct btrfsic_block_data_ctx *const first_block_ctx,
 980                int first_limit_nesting, int force_iodone_flag)
 981{
 982        struct btrfsic_stack_frame initial_stack_frame = { 0 };
 983        struct btrfsic_stack_frame *sf;
 984        struct btrfsic_stack_frame *next_stack;
 985        struct btrfs_header *const first_hdr =
 986                (struct btrfs_header *)first_block_ctx->datav[0];
 987
 988        BUG_ON(!first_hdr);
 989        sf = &initial_stack_frame;
 990        sf->error = 0;
 991        sf->i = -1;
 992        sf->limit_nesting = first_limit_nesting;
 993        sf->block = first_block;
 994        sf->block_ctx = first_block_ctx;
 995        sf->next_block = NULL;
 996        sf->hdr = first_hdr;
 997        sf->prev = NULL;
 998
 999continue_with_new_stack_frame:
1000        sf->block->generation = le64_to_cpu(sf->hdr->generation);
1001        if (0 == sf->hdr->level) {
1002                struct btrfs_leaf *const leafhdr =
1003                    (struct btrfs_leaf *)sf->hdr;
1004
1005                if (-1 == sf->i) {
1006                        sf->nr = le32_to_cpu(leafhdr->header.nritems);
1007
1008                        if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1009                                printk(KERN_INFO
1010                                       "leaf %llu items %d generation %llu"
1011                                       " owner %llu\n",
1012                                       (unsigned long long)
1013                                       sf->block_ctx->start,
1014                                       sf->nr,
1015                                       (unsigned long long)
1016                                       le64_to_cpu(leafhdr->header.generation),
1017                                       (unsigned long long)
1018                                       le64_to_cpu(leafhdr->header.owner));
1019                }
1020
1021continue_with_current_leaf_stack_frame:
1022                if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1023                        sf->i++;
1024                        sf->num_copies = 0;
1025                }
1026
1027                if (sf->i < sf->nr) {
1028                        struct btrfs_item disk_item;
1029                        u32 disk_item_offset =
1030                                (uintptr_t)(leafhdr->items + sf->i) -
1031                                (uintptr_t)leafhdr;
1032                        struct btrfs_disk_key *disk_key;
1033                        u8 type;
1034                        u32 item_offset;
1035                        u32 item_size;
1036
1037                        if (disk_item_offset + sizeof(struct btrfs_item) >
1038                            sf->block_ctx->len) {
1039leaf_item_out_of_bounce_error:
1040                                printk(KERN_INFO
1041                                       "btrfsic: leaf item out of bounce at logical %llu, dev %s\n",
1042                                       sf->block_ctx->start,
1043                                       sf->block_ctx->dev->name);
1044                                goto one_stack_frame_backwards;
1045                        }
1046                        btrfsic_read_from_block_data(sf->block_ctx,
1047                                                     &disk_item,
1048                                                     disk_item_offset,
1049                                                     sizeof(struct btrfs_item));
1050                        item_offset = le32_to_cpu(disk_item.offset);
1051                        item_size = le32_to_cpu(disk_item.size);
1052                        disk_key = &disk_item.key;
1053                        type = disk_key->type;
1054
1055                        if (BTRFS_ROOT_ITEM_KEY == type) {
1056                                struct btrfs_root_item root_item;
1057                                u32 root_item_offset;
1058                                u64 next_bytenr;
1059
1060                                root_item_offset = item_offset +
1061                                        offsetof(struct btrfs_leaf, items);
1062                                if (root_item_offset + item_size >
1063                                    sf->block_ctx->len)
1064                                        goto leaf_item_out_of_bounce_error;
1065                                btrfsic_read_from_block_data(
1066                                        sf->block_ctx, &root_item,
1067                                        root_item_offset,
1068                                        item_size);
1069                                next_bytenr = le64_to_cpu(root_item.bytenr);
1070
1071                                sf->error =
1072                                    btrfsic_create_link_to_next_block(
1073                                                state,
1074                                                sf->block,
1075                                                sf->block_ctx,
1076                                                next_bytenr,
1077                                                sf->limit_nesting,
1078                                                &sf->next_block_ctx,
1079                                                &sf->next_block,
1080                                                force_iodone_flag,
1081                                                &sf->num_copies,
1082                                                &sf->mirror_num,
1083                                                disk_key,
1084                                                le64_to_cpu(root_item.
1085                                                generation));
1086                                if (sf->error)
1087                                        goto one_stack_frame_backwards;
1088
1089                                if (NULL != sf->next_block) {
1090                                        struct btrfs_header *const next_hdr =
1091                                            (struct btrfs_header *)
1092                                            sf->next_block_ctx.datav[0];
1093
1094                                        next_stack =
1095                                            btrfsic_stack_frame_alloc();
1096                                        if (NULL == next_stack) {
1097                                                btrfsic_release_block_ctx(
1098                                                                &sf->
1099                                                                next_block_ctx);
1100                                                goto one_stack_frame_backwards;
1101                                        }
1102
1103                                        next_stack->i = -1;
1104                                        next_stack->block = sf->next_block;
1105                                        next_stack->block_ctx =
1106                                            &sf->next_block_ctx;
1107                                        next_stack->next_block = NULL;
1108                                        next_stack->hdr = next_hdr;
1109                                        next_stack->limit_nesting =
1110                                            sf->limit_nesting - 1;
1111                                        next_stack->prev = sf;
1112                                        sf = next_stack;
1113                                        goto continue_with_new_stack_frame;
1114                                }
1115                        } else if (BTRFS_EXTENT_DATA_KEY == type &&
1116                                   state->include_extent_data) {
1117                                sf->error = btrfsic_handle_extent_data(
1118                                                state,
1119                                                sf->block,
1120                                                sf->block_ctx,
1121                                                item_offset,
1122                                                force_iodone_flag);
1123                                if (sf->error)
1124                                        goto one_stack_frame_backwards;
1125                        }
1126
1127                        goto continue_with_current_leaf_stack_frame;
1128                }
1129        } else {
1130                struct btrfs_node *const nodehdr = (struct btrfs_node *)sf->hdr;
1131
1132                if (-1 == sf->i) {
1133                        sf->nr = le32_to_cpu(nodehdr->header.nritems);
1134
1135                        if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1136                                printk(KERN_INFO "node %llu level %d items %d"
1137                                       " generation %llu owner %llu\n",
1138                                       (unsigned long long)
1139                                       sf->block_ctx->start,
1140                                       nodehdr->header.level, sf->nr,
1141                                       (unsigned long long)
1142                                       le64_to_cpu(nodehdr->header.generation),
1143                                       (unsigned long long)
1144                                       le64_to_cpu(nodehdr->header.owner));
1145                }
1146
1147continue_with_current_node_stack_frame:
1148                if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1149                        sf->i++;
1150                        sf->num_copies = 0;
1151                }
1152
1153                if (sf->i < sf->nr) {
1154                        struct btrfs_key_ptr key_ptr;
1155                        u32 key_ptr_offset;
1156                        u64 next_bytenr;
1157
1158                        key_ptr_offset = (uintptr_t)(nodehdr->ptrs + sf->i) -
1159                                          (uintptr_t)nodehdr;
1160                        if (key_ptr_offset + sizeof(struct btrfs_key_ptr) >
1161                            sf->block_ctx->len) {
1162                                printk(KERN_INFO
1163                                       "btrfsic: node item out of bounce at logical %llu, dev %s\n",
1164                                       sf->block_ctx->start,
1165                                       sf->block_ctx->dev->name);
1166                                goto one_stack_frame_backwards;
1167                        }
1168                        btrfsic_read_from_block_data(
1169                                sf->block_ctx, &key_ptr, key_ptr_offset,
1170                                sizeof(struct btrfs_key_ptr));
1171                        next_bytenr = le64_to_cpu(key_ptr.blockptr);
1172
1173                        sf->error = btrfsic_create_link_to_next_block(
1174                                        state,
1175                                        sf->block,
1176                                        sf->block_ctx,
1177                                        next_bytenr,
1178                                        sf->limit_nesting,
1179                                        &sf->next_block_ctx,
1180                                        &sf->next_block,
1181                                        force_iodone_flag,
1182                                        &sf->num_copies,
1183                                        &sf->mirror_num,
1184                                        &key_ptr.key,
1185                                        le64_to_cpu(key_ptr.generation));
1186                        if (sf->error)
1187                                goto one_stack_frame_backwards;
1188
1189                        if (NULL != sf->next_block) {
1190                                struct btrfs_header *const next_hdr =
1191                                    (struct btrfs_header *)
1192                                    sf->next_block_ctx.datav[0];
1193
1194                                next_stack = btrfsic_stack_frame_alloc();
1195                                if (NULL == next_stack)
1196                                        goto one_stack_frame_backwards;
1197
1198                                next_stack->i = -1;
1199                                next_stack->block = sf->next_block;
1200                                next_stack->block_ctx = &sf->next_block_ctx;
1201                                next_stack->next_block = NULL;
1202                                next_stack->hdr = next_hdr;
1203                                next_stack->limit_nesting =
1204                                    sf->limit_nesting - 1;
1205                                next_stack->prev = sf;
1206                                sf = next_stack;
1207                                goto continue_with_new_stack_frame;
1208                        }
1209
1210                        goto continue_with_current_node_stack_frame;
1211                }
1212        }
1213
1214one_stack_frame_backwards:
1215        if (NULL != sf->prev) {
1216                struct btrfsic_stack_frame *const prev = sf->prev;
1217
1218                /* the one for the initial block is freed in the caller */
1219                btrfsic_release_block_ctx(sf->block_ctx);
1220
1221                if (sf->error) {
1222                        prev->error = sf->error;
1223                        btrfsic_stack_frame_free(sf);
1224                        sf = prev;
1225                        goto one_stack_frame_backwards;
1226                }
1227
1228                btrfsic_stack_frame_free(sf);
1229                sf = prev;
1230                goto continue_with_new_stack_frame;
1231        } else {
1232                BUG_ON(&initial_stack_frame != sf);
1233        }
1234
1235        return sf->error;
1236}
1237
1238static void btrfsic_read_from_block_data(
1239        struct btrfsic_block_data_ctx *block_ctx,
1240        void *dstv, u32 offset, size_t len)
1241{
1242        size_t cur;
1243        size_t offset_in_page;
1244        char *kaddr;
1245        char *dst = (char *)dstv;
1246        size_t start_offset = block_ctx->start & ((u64)PAGE_CACHE_SIZE - 1);
1247        unsigned long i = (start_offset + offset) >> PAGE_CACHE_SHIFT;
1248
1249        WARN_ON(offset + len > block_ctx->len);
1250        offset_in_page = (start_offset + offset) &
1251                         ((unsigned long)PAGE_CACHE_SIZE - 1);
1252
1253        while (len > 0) {
1254                cur = min(len, ((size_t)PAGE_CACHE_SIZE - offset_in_page));
1255                BUG_ON(i >= (block_ctx->len + PAGE_CACHE_SIZE - 1) >>
1256                            PAGE_CACHE_SHIFT);
1257                kaddr = block_ctx->datav[i];
1258                memcpy(dst, kaddr + offset_in_page, cur);
1259
1260                dst += cur;
1261                len -= cur;
1262                offset_in_page = 0;
1263                i++;
1264        }
1265}
1266
1267static int btrfsic_create_link_to_next_block(
1268                struct btrfsic_state *state,
1269                struct btrfsic_block *block,
1270                struct btrfsic_block_data_ctx *block_ctx,
1271                u64 next_bytenr,
1272                int limit_nesting,
1273                struct btrfsic_block_data_ctx *next_block_ctx,
1274                struct btrfsic_block **next_blockp,
1275                int force_iodone_flag,
1276                int *num_copiesp, int *mirror_nump,
1277                struct btrfs_disk_key *disk_key,
1278                u64 parent_generation)
1279{
1280        struct btrfsic_block *next_block = NULL;
1281        int ret;
1282        struct btrfsic_block_link *l;
1283        int did_alloc_block_link;
1284        int block_was_created;
1285
1286        *next_blockp = NULL;
1287        if (0 == *num_copiesp) {
1288                *num_copiesp =
1289                    btrfs_num_copies(&state->root->fs_info->mapping_tree,
1290                                     next_bytenr, state->metablock_size);
1291                if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1292                        printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1293                               (unsigned long long)next_bytenr, *num_copiesp);
1294                *mirror_nump = 1;
1295        }
1296
1297        if (*mirror_nump > *num_copiesp)
1298                return 0;
1299
1300        if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1301                printk(KERN_INFO
1302                       "btrfsic_create_link_to_next_block(mirror_num=%d)\n",
1303                       *mirror_nump);
1304        ret = btrfsic_map_block(state, next_bytenr,
1305                                state->metablock_size,
1306                                next_block_ctx, *mirror_nump);
1307        if (ret) {
1308                printk(KERN_INFO
1309                       "btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1310                       (unsigned long long)next_bytenr, *mirror_nump);
1311                btrfsic_release_block_ctx(next_block_ctx);
1312                *next_blockp = NULL;
1313                return -1;
1314        }
1315
1316        next_block = btrfsic_block_lookup_or_add(state,
1317                                                 next_block_ctx, "referenced ",
1318                                                 1, force_iodone_flag,
1319                                                 !force_iodone_flag,
1320                                                 *mirror_nump,
1321                                                 &block_was_created);
1322        if (NULL == next_block) {
1323                btrfsic_release_block_ctx(next_block_ctx);
1324                *next_blockp = NULL;
1325                return -1;
1326        }
1327        if (block_was_created) {
1328                l = NULL;
1329                next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
1330        } else {
1331                if (next_block->logical_bytenr != next_bytenr &&
1332                    !(!next_block->is_metadata &&
1333                      0 == next_block->logical_bytenr)) {
1334                        printk(KERN_INFO
1335                               "Referenced block @%llu (%s/%llu/%d)"
1336                               " found in hash table, %c,"
1337                               " bytenr mismatch (!= stored %llu).\n",
1338                               (unsigned long long)next_bytenr,
1339                               next_block_ctx->dev->name,
1340                               (unsigned long long)next_block_ctx->dev_bytenr,
1341                               *mirror_nump,
1342                               btrfsic_get_block_type(state, next_block),
1343                               (unsigned long long)next_block->logical_bytenr);
1344                } else if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1345                        printk(KERN_INFO
1346                               "Referenced block @%llu (%s/%llu/%d)"
1347                               " found in hash table, %c.\n",
1348                               (unsigned long long)next_bytenr,
1349                               next_block_ctx->dev->name,
1350                               (unsigned long long)next_block_ctx->dev_bytenr,
1351                               *mirror_nump,
1352                               btrfsic_get_block_type(state, next_block));
1353                next_block->logical_bytenr = next_bytenr;
1354
1355                next_block->mirror_num = *mirror_nump;
1356                l = btrfsic_block_link_hashtable_lookup(
1357                                next_block_ctx->dev->bdev,
1358                                next_block_ctx->dev_bytenr,
1359                                block_ctx->dev->bdev,
1360                                block_ctx->dev_bytenr,
1361                                &state->block_link_hashtable);
1362        }
1363
1364        next_block->disk_key = *disk_key;
1365        if (NULL == l) {
1366                l = btrfsic_block_link_alloc();
1367                if (NULL == l) {
1368                        printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
1369                        btrfsic_release_block_ctx(next_block_ctx);
1370                        *next_blockp = NULL;
1371                        return -1;
1372                }
1373
1374                did_alloc_block_link = 1;
1375                l->block_ref_to = next_block;
1376                l->block_ref_from = block;
1377                l->ref_cnt = 1;
1378                l->parent_generation = parent_generation;
1379
1380                if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1381                        btrfsic_print_add_link(state, l);
1382
1383                list_add(&l->node_ref_to, &block->ref_to_list);
1384                list_add(&l->node_ref_from, &next_block->ref_from_list);
1385
1386                btrfsic_block_link_hashtable_add(l,
1387                                                 &state->block_link_hashtable);
1388        } else {
1389                did_alloc_block_link = 0;
1390                if (0 == limit_nesting) {
1391                        l->ref_cnt++;
1392                        l->parent_generation = parent_generation;
1393                        if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1394                                btrfsic_print_add_link(state, l);
1395                }
1396        }
1397
1398        if (limit_nesting > 0 && did_alloc_block_link) {
1399                ret = btrfsic_read_block(state, next_block_ctx);
1400                if (ret < (int)next_block_ctx->len) {
1401                        printk(KERN_INFO
1402                               "btrfsic: read block @logical %llu failed!\n",
1403                               (unsigned long long)next_bytenr);
1404                        btrfsic_release_block_ctx(next_block_ctx);
1405                        *next_blockp = NULL;
1406                        return -1;
1407                }
1408
1409                *next_blockp = next_block;
1410        } else {
1411                *next_blockp = NULL;
1412        }
1413        (*mirror_nump)++;
1414
1415        return 0;
1416}
1417
1418static int btrfsic_handle_extent_data(
1419                struct btrfsic_state *state,
1420                struct btrfsic_block *block,
1421                struct btrfsic_block_data_ctx *block_ctx,
1422                u32 item_offset, int force_iodone_flag)
1423{
1424        int ret;
1425        struct btrfs_file_extent_item file_extent_item;
1426        u64 file_extent_item_offset;
1427        u64 next_bytenr;
1428        u64 num_bytes;
1429        u64 generation;
1430        struct btrfsic_block_link *l;
1431
1432        file_extent_item_offset = offsetof(struct btrfs_leaf, items) +
1433                                  item_offset;
1434        if (file_extent_item_offset +
1435            offsetof(struct btrfs_file_extent_item, disk_num_bytes) >
1436            block_ctx->len) {
1437                printk(KERN_INFO
1438                       "btrfsic: file item out of bounce at logical %llu, dev %s\n",
1439                       block_ctx->start, block_ctx->dev->name);
1440                return -1;
1441        }
1442
1443        btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1444                file_extent_item_offset,
1445                offsetof(struct btrfs_file_extent_item, disk_num_bytes));
1446        if (BTRFS_FILE_EXTENT_REG != file_extent_item.type ||
1447            ((u64)0) == le64_to_cpu(file_extent_item.disk_bytenr)) {
1448                if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1449                        printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu\n",
1450                               file_extent_item.type,
1451                               (unsigned long long)
1452                               le64_to_cpu(file_extent_item.disk_bytenr));
1453                return 0;
1454        }
1455
1456        if (file_extent_item_offset + sizeof(struct btrfs_file_extent_item) >
1457            block_ctx->len) {
1458                printk(KERN_INFO
1459                       "btrfsic: file item out of bounce at logical %llu, dev %s\n",
1460                       block_ctx->start, block_ctx->dev->name);
1461                return -1;
1462        }
1463        btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1464                                     file_extent_item_offset,
1465                                     sizeof(struct btrfs_file_extent_item));
1466        next_bytenr = le64_to_cpu(file_extent_item.disk_bytenr) +
1467                      le64_to_cpu(file_extent_item.offset);
1468        generation = le64_to_cpu(file_extent_item.generation);
1469        num_bytes = le64_to_cpu(file_extent_item.num_bytes);
1470        generation = le64_to_cpu(file_extent_item.generation);
1471
1472        if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1473                printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu,"
1474                       " offset = %llu, num_bytes = %llu\n",
1475                       file_extent_item.type,
1476                       (unsigned long long)
1477                       le64_to_cpu(file_extent_item.disk_bytenr),
1478                       (unsigned long long)le64_to_cpu(file_extent_item.offset),
1479                       (unsigned long long)num_bytes);
1480        while (num_bytes > 0) {
1481                u32 chunk_len;
1482                int num_copies;
1483                int mirror_num;
1484
1485                if (num_bytes > state->datablock_size)
1486                        chunk_len = state->datablock_size;
1487                else
1488                        chunk_len = num_bytes;
1489
1490                num_copies =
1491                    btrfs_num_copies(&state->root->fs_info->mapping_tree,
1492                                     next_bytenr, state->datablock_size);
1493                if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1494                        printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1495                               (unsigned long long)next_bytenr, num_copies);
1496                for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
1497                        struct btrfsic_block_data_ctx next_block_ctx;
1498                        struct btrfsic_block *next_block;
1499                        int block_was_created;
1500
1501                        if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1502                                printk(KERN_INFO "btrfsic_handle_extent_data("
1503                                       "mirror_num=%d)\n", mirror_num);
1504                        if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1505                                printk(KERN_INFO
1506                                       "\tdisk_bytenr = %llu, num_bytes %u\n",
1507                                       (unsigned long long)next_bytenr,
1508                                       chunk_len);
1509                        ret = btrfsic_map_block(state, next_bytenr,
1510                                                chunk_len, &next_block_ctx,
1511                                                mirror_num);
1512                        if (ret) {
1513                                printk(KERN_INFO
1514                                       "btrfsic: btrfsic_map_block(@%llu,"
1515                                       " mirror=%d) failed!\n",
1516                                       (unsigned long long)next_bytenr,
1517                                       mirror_num);
1518                                return -1;
1519                        }
1520
1521                        next_block = btrfsic_block_lookup_or_add(
1522                                        state,
1523                                        &next_block_ctx,
1524                                        "referenced ",
1525                                        0,
1526                                        force_iodone_flag,
1527                                        !force_iodone_flag,
1528                                        mirror_num,
1529                                        &block_was_created);
1530                        if (NULL == next_block) {
1531                                printk(KERN_INFO
1532                                       "btrfsic: error, kmalloc failed!\n");
1533                                btrfsic_release_block_ctx(&next_block_ctx);
1534                                return -1;
1535                        }
1536                        if (!block_was_created) {
1537                                if (next_block->logical_bytenr != next_bytenr &&
1538                                    !(!next_block->is_metadata &&
1539                                      0 == next_block->logical_bytenr)) {
1540                                        printk(KERN_INFO
1541                                               "Referenced block"
1542                                               " @%llu (%s/%llu/%d)"
1543                                               " found in hash table, D,"
1544                                               " bytenr mismatch"
1545                                               " (!= stored %llu).\n",
1546                                               (unsigned long long)next_bytenr,
1547                                               next_block_ctx.dev->name,
1548                                               (unsigned long long)
1549                                               next_block_ctx.dev_bytenr,
1550                                               mirror_num,
1551                                               (unsigned long long)
1552                                               next_block->logical_bytenr);
1553                                }
1554                                next_block->logical_bytenr = next_bytenr;
1555                                next_block->mirror_num = mirror_num;
1556                        }
1557
1558                        l = btrfsic_block_link_lookup_or_add(state,
1559                                                             &next_block_ctx,
1560                                                             next_block, block,
1561                                                             generation);
1562                        btrfsic_release_block_ctx(&next_block_ctx);
1563                        if (NULL == l)
1564                                return -1;
1565                }
1566
1567                next_bytenr += chunk_len;
1568                num_bytes -= chunk_len;
1569        }
1570
1571        return 0;
1572}
1573
1574static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
1575                             struct btrfsic_block_data_ctx *block_ctx_out,
1576                             int mirror_num)
1577{
1578        int ret;
1579        u64 length;
1580        struct btrfs_bio *multi = NULL;
1581        struct btrfs_device *device;
1582
1583        length = len;
1584        ret = btrfs_map_block(&state->root->fs_info->mapping_tree, READ,
1585                              bytenr, &length, &multi, mirror_num);
1586
1587        device = multi->stripes[0].dev;
1588        block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev);
1589        block_ctx_out->dev_bytenr = multi->stripes[0].physical;
1590        block_ctx_out->start = bytenr;
1591        block_ctx_out->len = len;
1592        block_ctx_out->datav = NULL;
1593        block_ctx_out->pagev = NULL;
1594        block_ctx_out->mem_to_free = NULL;
1595
1596        if (0 == ret)
1597                kfree(multi);
1598        if (NULL == block_ctx_out->dev) {
1599                ret = -ENXIO;
1600                printk(KERN_INFO "btrfsic: error, cannot lookup dev (#1)!\n");
1601        }
1602
1603        return ret;
1604}
1605
1606static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
1607                                  u32 len, struct block_device *bdev,
1608                                  struct btrfsic_block_data_ctx *block_ctx_out)
1609{
1610        block_ctx_out->dev = btrfsic_dev_state_lookup(bdev);
1611        block_ctx_out->dev_bytenr = bytenr;
1612        block_ctx_out->start = bytenr;
1613        block_ctx_out->len = len;
1614        block_ctx_out->datav = NULL;
1615        block_ctx_out->pagev = NULL;
1616        block_ctx_out->mem_to_free = NULL;
1617        if (NULL != block_ctx_out->dev) {
1618                return 0;
1619        } else {
1620                printk(KERN_INFO "btrfsic: error, cannot lookup dev (#2)!\n");
1621                return -ENXIO;
1622        }
1623}
1624
1625static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
1626{
1627        if (block_ctx->mem_to_free) {
1628                unsigned int num_pages;
1629
1630                BUG_ON(!block_ctx->datav);
1631                BUG_ON(!block_ctx->pagev);
1632                num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
1633                            PAGE_CACHE_SHIFT;
1634                while (num_pages > 0) {
1635                        num_pages--;
1636                        if (block_ctx->datav[num_pages]) {
1637                                kunmap(block_ctx->pagev[num_pages]);
1638                                block_ctx->datav[num_pages] = NULL;
1639                        }
1640                        if (block_ctx->pagev[num_pages]) {
1641                                __free_page(block_ctx->pagev[num_pages]);
1642                                block_ctx->pagev[num_pages] = NULL;
1643                        }
1644                }
1645
1646                kfree(block_ctx->mem_to_free);
1647                block_ctx->mem_to_free = NULL;
1648                block_ctx->pagev = NULL;
1649                block_ctx->datav = NULL;
1650        }
1651}
1652
1653static int btrfsic_read_block(struct btrfsic_state *state,
1654                              struct btrfsic_block_data_ctx *block_ctx)
1655{
1656        unsigned int num_pages;
1657        unsigned int i;
1658        u64 dev_bytenr;
1659        int ret;
1660
1661        BUG_ON(block_ctx->datav);
1662        BUG_ON(block_ctx->pagev);
1663        BUG_ON(block_ctx->mem_to_free);
1664        if (block_ctx->dev_bytenr & ((u64)PAGE_CACHE_SIZE - 1)) {
1665                printk(KERN_INFO
1666                       "btrfsic: read_block() with unaligned bytenr %llu\n",
1667                       (unsigned long long)block_ctx->dev_bytenr);
1668                return -1;
1669        }
1670
1671        num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
1672                    PAGE_CACHE_SHIFT;
1673        block_ctx->mem_to_free = kzalloc((sizeof(*block_ctx->datav) +
1674                                          sizeof(*block_ctx->pagev)) *
1675                                         num_pages, GFP_NOFS);
1676        if (!block_ctx->mem_to_free)
1677                return -1;
1678        block_ctx->datav = block_ctx->mem_to_free;
1679        block_ctx->pagev = (struct page **)(block_ctx->datav + num_pages);
1680        for (i = 0; i < num_pages; i++) {
1681                block_ctx->pagev[i] = alloc_page(GFP_NOFS);
1682                if (!block_ctx->pagev[i])
1683                        return -1;
1684        }
1685
1686        dev_bytenr = block_ctx->dev_bytenr;
1687        for (i = 0; i < num_pages;) {
1688                struct bio *bio;
1689                unsigned int j;
1690                DECLARE_COMPLETION_ONSTACK(complete);
1691
1692                bio = bio_alloc(GFP_NOFS, num_pages - i);
1693                if (!bio) {
1694                        printk(KERN_INFO
1695                               "btrfsic: bio_alloc() for %u pages failed!\n",
1696                               num_pages - i);
1697                        return -1;
1698                }
1699                bio->bi_bdev = block_ctx->dev->bdev;
1700                bio->bi_sector = dev_bytenr >> 9;
1701                bio->bi_end_io = btrfsic_complete_bio_end_io;
1702                bio->bi_private = &complete;
1703
1704                for (j = i; j < num_pages; j++) {
1705                        ret = bio_add_page(bio, block_ctx->pagev[j],
1706                                           PAGE_CACHE_SIZE, 0);
1707                        if (PAGE_CACHE_SIZE != ret)
1708                                break;
1709                }
1710                if (j == i) {
1711                        printk(KERN_INFO
1712                               "btrfsic: error, failed to add a single page!\n");
1713                        return -1;
1714                }
1715                submit_bio(READ, bio);
1716
1717                /* this will also unplug the queue */
1718                wait_for_completion(&complete);
1719
1720                if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
1721                        printk(KERN_INFO
1722                               "btrfsic: read error at logical %llu dev %s!\n",
1723                               block_ctx->start, block_ctx->dev->name);
1724                        bio_put(bio);
1725                        return -1;
1726                }
1727                bio_put(bio);
1728                dev_bytenr += (j - i) * PAGE_CACHE_SIZE;
1729                i = j;
1730        }
1731        for (i = 0; i < num_pages; i++) {
1732                block_ctx->datav[i] = kmap(block_ctx->pagev[i]);
1733                if (!block_ctx->datav[i]) {
1734                        printk(KERN_INFO "btrfsic: kmap() failed (dev %s)!\n",
1735                               block_ctx->dev->name);
1736                        return -1;
1737                }
1738        }
1739
1740        return block_ctx->len;
1741}
1742
1743static void btrfsic_complete_bio_end_io(struct bio *bio, int err)
1744{
1745        complete((struct completion *)bio->bi_private);
1746}
1747
1748static void btrfsic_dump_database(struct btrfsic_state *state)
1749{
1750        struct list_head *elem_all;
1751
1752        BUG_ON(NULL == state);
1753
1754        printk(KERN_INFO "all_blocks_list:\n");
1755        list_for_each(elem_all, &state->all_blocks_list) {
1756                const struct btrfsic_block *const b_all =
1757                    list_entry(elem_all, struct btrfsic_block,
1758                               all_blocks_node);
1759                struct list_head *elem_ref_to;
1760                struct list_head *elem_ref_from;
1761
1762                printk(KERN_INFO "%c-block @%llu (%s/%llu/%d)\n",
1763                       btrfsic_get_block_type(state, b_all),
1764                       (unsigned long long)b_all->logical_bytenr,
1765                       b_all->dev_state->name,
1766                       (unsigned long long)b_all->dev_bytenr,
1767                       b_all->mirror_num);
1768
1769                list_for_each(elem_ref_to, &b_all->ref_to_list) {
1770                        const struct btrfsic_block_link *const l =
1771                            list_entry(elem_ref_to,
1772                                       struct btrfsic_block_link,
1773                                       node_ref_to);
1774
1775                        printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1776                               " refers %u* to"
1777                               " %c @%llu (%s/%llu/%d)\n",
1778                               btrfsic_get_block_type(state, b_all),
1779                               (unsigned long long)b_all->logical_bytenr,
1780                               b_all->dev_state->name,
1781                               (unsigned long long)b_all->dev_bytenr,
1782                               b_all->mirror_num,
1783                               l->ref_cnt,
1784                               btrfsic_get_block_type(state, l->block_ref_to),
1785                               (unsigned long long)
1786                               l->block_ref_to->logical_bytenr,
1787                               l->block_ref_to->dev_state->name,
1788                               (unsigned long long)l->block_ref_to->dev_bytenr,
1789                               l->block_ref_to->mirror_num);
1790                }
1791
1792                list_for_each(elem_ref_from, &b_all->ref_from_list) {
1793                        const struct btrfsic_block_link *const l =
1794                            list_entry(elem_ref_from,
1795                                       struct btrfsic_block_link,
1796                                       node_ref_from);
1797
1798                        printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1799                               " is ref %u* from"
1800                               " %c @%llu (%s/%llu/%d)\n",
1801                               btrfsic_get_block_type(state, b_all),
1802                               (unsigned long long)b_all->logical_bytenr,
1803                               b_all->dev_state->name,
1804                               (unsigned long long)b_all->dev_bytenr,
1805                               b_all->mirror_num,
1806                               l->ref_cnt,
1807                               btrfsic_get_block_type(state, l->block_ref_from),
1808                               (unsigned long long)
1809                               l->block_ref_from->logical_bytenr,
1810                               l->block_ref_from->dev_state->name,
1811                               (unsigned long long)
1812                               l->block_ref_from->dev_bytenr,
1813                               l->block_ref_from->mirror_num);
1814                }
1815
1816                printk(KERN_INFO "\n");
1817        }
1818}
1819
1820/*
1821 * Test whether the disk block contains a tree block (leaf or node)
1822 * (note that this test fails for the super block)
1823 */
1824static int btrfsic_test_for_metadata(struct btrfsic_state *state,
1825                                     char **datav, unsigned int num_pages)
1826{
1827        struct btrfs_header *h;
1828        u8 csum[BTRFS_CSUM_SIZE];
1829        u32 crc = ~(u32)0;
1830        unsigned int i;
1831
1832        if (num_pages * PAGE_CACHE_SIZE < state->metablock_size)
1833                return 1; /* not metadata */
1834        num_pages = state->metablock_size >> PAGE_CACHE_SHIFT;
1835        h = (struct btrfs_header *)datav[0];
1836
1837        if (memcmp(h->fsid, state->root->fs_info->fsid, BTRFS_UUID_SIZE))
1838                return 1;
1839
1840        for (i = 0; i < num_pages; i++) {
1841                u8 *data = i ? datav[i] : (datav[i] + BTRFS_CSUM_SIZE);
1842                size_t sublen = i ? PAGE_CACHE_SIZE :
1843                                    (PAGE_CACHE_SIZE - BTRFS_CSUM_SIZE);
1844
1845                crc = crc32c(crc, data, sublen);
1846        }
1847        btrfs_csum_final(crc, csum);
1848        if (memcmp(csum, h->csum, state->csum_size))
1849                return 1;
1850
1851        return 0; /* is metadata */
1852}
1853
1854static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
1855                                          u64 dev_bytenr, char **mapped_datav,
1856                                          unsigned int num_pages,
1857                                          struct bio *bio, int *bio_is_patched,
1858                                          struct buffer_head *bh,
1859                                          int submit_bio_bh_rw)
1860{
1861        int is_metadata;
1862        struct btrfsic_block *block;
1863        struct btrfsic_block_data_ctx block_ctx;
1864        int ret;
1865        struct btrfsic_state *state = dev_state->state;
1866        struct block_device *bdev = dev_state->bdev;
1867        unsigned int processed_len;
1868
1869        if (NULL != bio_is_patched)
1870                *bio_is_patched = 0;
1871
1872again:
1873        if (num_pages == 0)
1874                return;
1875
1876        processed_len = 0;
1877        is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_datav,
1878                                                      num_pages));
1879
1880        block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
1881                                               &state->block_hashtable);
1882        if (NULL != block) {
1883                u64 bytenr = 0;
1884                struct list_head *elem_ref_to;
1885                struct list_head *tmp_ref_to;
1886
1887                if (block->is_superblock) {
1888                        bytenr = le64_to_cpu(((struct btrfs_super_block *)
1889                                              mapped_datav[0])->bytenr);
1890                        if (num_pages * PAGE_CACHE_SIZE <
1891                            BTRFS_SUPER_INFO_SIZE) {
1892                                printk(KERN_INFO
1893                                       "btrfsic: cannot work with too short bios!\n");
1894                                return;
1895                        }
1896                        is_metadata = 1;
1897                        BUG_ON(BTRFS_SUPER_INFO_SIZE & (PAGE_CACHE_SIZE - 1));
1898                        processed_len = BTRFS_SUPER_INFO_SIZE;
1899                        if (state->print_mask &
1900                            BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
1901                                printk(KERN_INFO
1902                                       "[before new superblock is written]:\n");
1903                                btrfsic_dump_tree_sub(state, block, 0);
1904                        }
1905                }
1906                if (is_metadata) {
1907                        if (!block->is_superblock) {
1908                                if (num_pages * PAGE_CACHE_SIZE <
1909                                    state->metablock_size) {
1910                                        printk(KERN_INFO
1911                                               "btrfsic: cannot work with too short bios!\n");
1912                                        return;
1913                                }
1914                                processed_len = state->metablock_size;
1915                                bytenr = le64_to_cpu(((struct btrfs_header *)
1916                                                      mapped_datav[0])->bytenr);
1917                                btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
1918                                                               dev_state,
1919                                                               dev_bytenr);
1920                        }
1921                        if (block->logical_bytenr != bytenr) {
1922                                printk(KERN_INFO
1923                                       "Written block @%llu (%s/%llu/%d)"
1924                                       " found in hash table, %c,"
1925                                       " bytenr mismatch"
1926                                       " (!= stored %llu).\n",
1927                                       (unsigned long long)bytenr,
1928                                       dev_state->name,
1929                                       (unsigned long long)dev_bytenr,
1930                                       block->mirror_num,
1931                                       btrfsic_get_block_type(state, block),
1932                                       (unsigned long long)
1933                                       block->logical_bytenr);
1934                                block->logical_bytenr = bytenr;
1935                        } else if (state->print_mask &
1936                                   BTRFSIC_PRINT_MASK_VERBOSE)
1937                                printk(KERN_INFO
1938                                       "Written block @%llu (%s/%llu/%d)"
1939                                       " found in hash table, %c.\n",
1940                                       (unsigned long long)bytenr,
1941                                       dev_state->name,
1942                                       (unsigned long long)dev_bytenr,
1943                                       block->mirror_num,
1944                                       btrfsic_get_block_type(state, block));
1945                } else {
1946                        if (num_pages * PAGE_CACHE_SIZE <
1947                            state->datablock_size) {
1948                                printk(KERN_INFO
1949                                       "btrfsic: cannot work with too short bios!\n");
1950                                return;
1951                        }
1952                        processed_len = state->datablock_size;
1953                        bytenr = block->logical_bytenr;
1954                        if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1955                                printk(KERN_INFO
1956                                       "Written block @%llu (%s/%llu/%d)"
1957                                       " found in hash table, %c.\n",
1958                                       (unsigned long long)bytenr,
1959                                       dev_state->name,
1960                                       (unsigned long long)dev_bytenr,
1961                                       block->mirror_num,
1962                                       btrfsic_get_block_type(state, block));
1963                }
1964
1965                if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1966                        printk(KERN_INFO
1967                               "ref_to_list: %cE, ref_from_list: %cE\n",
1968                               list_empty(&block->ref_to_list) ? ' ' : '!',
1969                               list_empty(&block->ref_from_list) ? ' ' : '!');
1970                if (btrfsic_is_block_ref_by_superblock(state, block, 0)) {
1971                        printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
1972                               " @%llu (%s/%llu/%d), old(gen=%llu,"
1973                               " objectid=%llu, type=%d, offset=%llu),"
1974                               " new(gen=%llu),"
1975                               " which is referenced by most recent superblock"
1976                               " (superblockgen=%llu)!\n",
1977                               btrfsic_get_block_type(state, block),
1978                               (unsigned long long)bytenr,
1979                               dev_state->name,
1980                               (unsigned long long)dev_bytenr,
1981                               block->mirror_num,
1982                               (unsigned long long)block->generation,
1983                               (unsigned long long)
1984                               le64_to_cpu(block->disk_key.objectid),
1985                               block->disk_key.type,
1986                               (unsigned long long)
1987                               le64_to_cpu(block->disk_key.offset),
1988                               (unsigned long long)
1989                               le64_to_cpu(((struct btrfs_header *)
1990                                            mapped_datav[0])->generation),
1991                               (unsigned long long)
1992                               state->max_superblock_generation);
1993                        btrfsic_dump_tree(state);
1994                }
1995
1996                if (!block->is_iodone && !block->never_written) {
1997                        printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
1998                               " @%llu (%s/%llu/%d), oldgen=%llu, newgen=%llu,"
1999                               " which is not yet iodone!\n",
2000                               btrfsic_get_block_type(state, block),
2001                               (unsigned long long)bytenr,
2002                               dev_state->name,
2003                               (unsigned long long)dev_bytenr,
2004                               block->mirror_num,
2005                               (unsigned long long)block->generation,
2006                               (unsigned long long)
2007                               le64_to_cpu(((struct btrfs_header *)
2008                                            mapped_datav[0])->generation));
2009                        /* it would not be safe to go on */
2010                        btrfsic_dump_tree(state);
2011                        goto continue_loop;
2012                }
2013
2014                /*
2015                 * Clear all references of this block. Do not free
2016                 * the block itself even if is not referenced anymore
2017                 * because it still carries valueable information
2018                 * like whether it was ever written and IO completed.
2019                 */
2020                list_for_each_safe(elem_ref_to, tmp_ref_to,
2021                                   &block->ref_to_list) {
2022                        struct btrfsic_block_link *const l =
2023                            list_entry(elem_ref_to,
2024                                       struct btrfsic_block_link,
2025                                       node_ref_to);
2026
2027                        if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2028                                btrfsic_print_rem_link(state, l);
2029                        l->ref_cnt--;
2030                        if (0 == l->ref_cnt) {
2031                                list_del(&l->node_ref_to);
2032                                list_del(&l->node_ref_from);
2033                                btrfsic_block_link_hashtable_remove(l);
2034                                btrfsic_block_link_free(l);
2035                        }
2036                }
2037
2038                if (block->is_superblock)
2039                        ret = btrfsic_map_superblock(state, bytenr,
2040                                                     processed_len,
2041                                                     bdev, &block_ctx);
2042                else
2043                        ret = btrfsic_map_block(state, bytenr, processed_len,
2044                                                &block_ctx, 0);
2045                if (ret) {
2046                        printk(KERN_INFO
2047                               "btrfsic: btrfsic_map_block(root @%llu)"
2048                               " failed!\n", (unsigned long long)bytenr);
2049                        goto continue_loop;
2050                }
2051                block_ctx.datav = mapped_datav;
2052                /* the following is required in case of writes to mirrors,
2053                 * use the same that was used for the lookup */
2054                block_ctx.dev = dev_state;
2055                block_ctx.dev_bytenr = dev_bytenr;
2056
2057                if (is_metadata || state->include_extent_data) {
2058                        block->never_written = 0;
2059                        block->iodone_w_error = 0;
2060                        if (NULL != bio) {
2061                                block->is_iodone = 0;
2062                                BUG_ON(NULL == bio_is_patched);
2063                                if (!*bio_is_patched) {
2064                                        block->orig_bio_bh_private =
2065                                            bio->bi_private;
2066                                        block->orig_bio_bh_end_io.bio =
2067                                            bio->bi_end_io;
2068                                        block->next_in_same_bio = NULL;
2069                                        bio->bi_private = block;
2070                                        bio->bi_end_io = btrfsic_bio_end_io;
2071                                        *bio_is_patched = 1;
2072                                } else {
2073                                        struct btrfsic_block *chained_block =
2074                                            (struct btrfsic_block *)
2075                                            bio->bi_private;
2076
2077                                        BUG_ON(NULL == chained_block);
2078                                        block->orig_bio_bh_private =
2079                                            chained_block->orig_bio_bh_private;
2080                                        block->orig_bio_bh_end_io.bio =
2081                                            chained_block->orig_bio_bh_end_io.
2082                                            bio;
2083                                        block->next_in_same_bio = chained_block;
2084                                        bio->bi_private = block;
2085                                }
2086                        } else if (NULL != bh) {
2087                                block->is_iodone = 0;
2088                                block->orig_bio_bh_private = bh->b_private;
2089                                block->orig_bio_bh_end_io.bh = bh->b_end_io;
2090                                block->next_in_same_bio = NULL;
2091                                bh->b_private = block;
2092                                bh->b_end_io = btrfsic_bh_end_io;
2093                        } else {
2094                                block->is_iodone = 1;
2095                                block->orig_bio_bh_private = NULL;
2096                                block->orig_bio_bh_end_io.bio = NULL;
2097                                block->next_in_same_bio = NULL;
2098                        }
2099                }
2100
2101                block->flush_gen = dev_state->last_flush_gen + 1;
2102                block->submit_bio_bh_rw = submit_bio_bh_rw;
2103                if (is_metadata) {
2104                        block->logical_bytenr = bytenr;
2105                        block->is_metadata = 1;
2106                        if (block->is_superblock) {
2107                                BUG_ON(PAGE_CACHE_SIZE !=
2108                                       BTRFS_SUPER_INFO_SIZE);
2109                                ret = btrfsic_process_written_superblock(
2110                                                state,
2111                                                block,
2112                                                (struct btrfs_super_block *)
2113                                                mapped_datav[0]);
2114                                if (state->print_mask &
2115                                    BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE) {
2116                                        printk(KERN_INFO
2117                                        "[after new superblock is written]:\n");
2118                                        btrfsic_dump_tree_sub(state, block, 0);
2119                                }
2120                        } else {
2121                                block->mirror_num = 0;  /* unknown */
2122                                ret = btrfsic_process_metablock(
2123                                                state,
2124                                                block,
2125                                                &block_ctx,
2126                                                0, 0);
2127                        }
2128                        if (ret)
2129                                printk(KERN_INFO
2130                                       "btrfsic: btrfsic_process_metablock"
2131                                       "(root @%llu) failed!\n",
2132                                       (unsigned long long)dev_bytenr);
2133                } else {
2134                        block->is_metadata = 0;
2135                        block->mirror_num = 0;  /* unknown */
2136                        block->generation = BTRFSIC_GENERATION_UNKNOWN;
2137                        if (!state->include_extent_data
2138                            && list_empty(&block->ref_from_list)) {
2139                                /*
2140                                 * disk block is overwritten with extent
2141                                 * data (not meta data) and we are configured
2142                                 * to not include extent data: take the
2143                                 * chance and free the block's memory
2144                                 */
2145                                btrfsic_block_hashtable_remove(block);
2146                                list_del(&block->all_blocks_node);
2147                                btrfsic_block_free(block);
2148                        }
2149                }
2150                btrfsic_release_block_ctx(&block_ctx);
2151        } else {
2152                /* block has not been found in hash table */
2153                u64 bytenr;
2154
2155                if (!is_metadata) {
2156                        processed_len = state->datablock_size;
2157                        if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2158                                printk(KERN_INFO "Written block (%s/%llu/?)"
2159                                       " !found in hash table, D.\n",
2160                                       dev_state->name,
2161                                       (unsigned long long)dev_bytenr);
2162                        if (!state->include_extent_data) {
2163                                /* ignore that written D block */
2164                                goto continue_loop;
2165                        }
2166
2167                        /* this is getting ugly for the
2168                         * include_extent_data case... */
2169                        bytenr = 0;     /* unknown */
2170                        block_ctx.start = bytenr;
2171                        block_ctx.len = processed_len;
2172                        block_ctx.mem_to_free = NULL;
2173                        block_ctx.pagev = NULL;
2174                } else {
2175                        processed_len = state->metablock_size;
2176                        bytenr = le64_to_cpu(((struct btrfs_header *)
2177                                              mapped_datav[0])->bytenr);
2178                        btrfsic_cmp_log_and_dev_bytenr(state, bytenr, dev_state,
2179                                                       dev_bytenr);
2180                        if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2181                                printk(KERN_INFO
2182                                       "Written block @%llu (%s/%llu/?)"
2183                                       " !found in hash table, M.\n",
2184                                       (unsigned long long)bytenr,
2185                                       dev_state->name,
2186                                       (unsigned long long)dev_bytenr);
2187
2188                        ret = btrfsic_map_block(state, bytenr, processed_len,
2189                                                &block_ctx, 0);
2190                        if (ret) {
2191                                printk(KERN_INFO
2192                                       "btrfsic: btrfsic_map_block(root @%llu)"
2193                                       " failed!\n",
2194                                       (unsigned long long)dev_bytenr);
2195                                goto continue_loop;
2196                        }
2197                }
2198                block_ctx.datav = mapped_datav;
2199                /* the following is required in case of writes to mirrors,
2200                 * use the same that was used for the lookup */
2201                block_ctx.dev = dev_state;
2202                block_ctx.dev_bytenr = dev_bytenr;
2203
2204                block = btrfsic_block_alloc();
2205                if (NULL == block) {
2206                        printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2207                        btrfsic_release_block_ctx(&block_ctx);
2208                        goto continue_loop;
2209                }
2210                block->dev_state = dev_state;
2211                block->dev_bytenr = dev_bytenr;
2212                block->logical_bytenr = bytenr;
2213                block->is_metadata = is_metadata;
2214                block->never_written = 0;
2215                block->iodone_w_error = 0;
2216                block->mirror_num = 0;  /* unknown */
2217                block->flush_gen = dev_state->last_flush_gen + 1;
2218                block->submit_bio_bh_rw = submit_bio_bh_rw;
2219                if (NULL != bio) {
2220                        block->is_iodone = 0;
2221                        BUG_ON(NULL == bio_is_patched);
2222                        if (!*bio_is_patched) {
2223                                block->orig_bio_bh_private = bio->bi_private;
2224                                block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2225                                block->next_in_same_bio = NULL;
2226                                bio->bi_private = block;
2227                                bio->bi_end_io = btrfsic_bio_end_io;
2228                                *bio_is_patched = 1;
2229                        } else {
2230                                struct btrfsic_block *chained_block =
2231                                    (struct btrfsic_block *)
2232                                    bio->bi_private;
2233
2234                                BUG_ON(NULL == chained_block);
2235                                block->orig_bio_bh_private =
2236                                    chained_block->orig_bio_bh_private;
2237                                block->orig_bio_bh_end_io.bio =
2238                                    chained_block->orig_bio_bh_end_io.bio;
2239                                block->next_in_same_bio = chained_block;
2240                                bio->bi_private = block;
2241                        }
2242                } else if (NULL != bh) {
2243                        block->is_iodone = 0;
2244                        block->orig_bio_bh_private = bh->b_private;
2245                        block->orig_bio_bh_end_io.bh = bh->b_end_io;
2246                        block->next_in_same_bio = NULL;
2247                        bh->b_private = block;
2248                        bh->b_end_io = btrfsic_bh_end_io;
2249                } else {
2250                        block->is_iodone = 1;
2251                        block->orig_bio_bh_private = NULL;
2252                        block->orig_bio_bh_end_io.bio = NULL;
2253                        block->next_in_same_bio = NULL;
2254                }
2255                if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2256                        printk(KERN_INFO
2257                               "New written %c-block @%llu (%s/%llu/%d)\n",
2258                               is_metadata ? 'M' : 'D',
2259                               (unsigned long long)block->logical_bytenr,
2260                               block->dev_state->name,
2261                               (unsigned long long)block->dev_bytenr,
2262                               block->mirror_num);
2263                list_add(&block->all_blocks_node, &state->all_blocks_list);
2264                btrfsic_block_hashtable_add(block, &state->block_hashtable);
2265
2266                if (is_metadata) {
2267                        ret = btrfsic_process_metablock(state, block,
2268                                                        &block_ctx, 0, 0);
2269                        if (ret)
2270                                printk(KERN_INFO
2271                                       "btrfsic: process_metablock(root @%llu)"
2272                                       " failed!\n",
2273                                       (unsigned long long)dev_bytenr);
2274                }
2275                btrfsic_release_block_ctx(&block_ctx);
2276        }
2277
2278continue_loop:
2279        BUG_ON(!processed_len);
2280        dev_bytenr += processed_len;
2281        mapped_datav += processed_len >> PAGE_CACHE_SHIFT;
2282        num_pages -= processed_len >> PAGE_CACHE_SHIFT;
2283        goto again;
2284}
2285
2286static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status)
2287{
2288        struct btrfsic_block *block = (struct btrfsic_block *)bp->bi_private;
2289        int iodone_w_error;
2290
2291        /* mutex is not held! This is not save if IO is not yet completed
2292         * on umount */
2293        iodone_w_error = 0;
2294        if (bio_error_status)
2295                iodone_w_error = 1;
2296
2297        BUG_ON(NULL == block);
2298        bp->bi_private = block->orig_bio_bh_private;
2299        bp->bi_end_io = block->orig_bio_bh_end_io.bio;
2300
2301        do {
2302                struct btrfsic_block *next_block;
2303                struct btrfsic_dev_state *const dev_state = block->dev_state;
2304
2305                if ((dev_state->state->print_mask &
2306                     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2307                        printk(KERN_INFO
2308                               "bio_end_io(err=%d) for %c @%llu (%s/%llu/%d)\n",
2309                               bio_error_status,
2310                               btrfsic_get_block_type(dev_state->state, block),
2311                               (unsigned long long)block->logical_bytenr,
2312                               dev_state->name,
2313                               (unsigned long long)block->dev_bytenr,
2314                               block->mirror_num);
2315                next_block = block->next_in_same_bio;
2316                block->iodone_w_error = iodone_w_error;
2317                if (block->submit_bio_bh_rw & REQ_FLUSH) {
2318                        dev_state->last_flush_gen++;
2319                        if ((dev_state->state->print_mask &
2320                             BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2321                                printk(KERN_INFO
2322                                       "bio_end_io() new %s flush_gen=%llu\n",
2323                                       dev_state->name,
2324                                       (unsigned long long)
2325                                       dev_state->last_flush_gen);
2326                }
2327                if (block->submit_bio_bh_rw & REQ_FUA)
2328                        block->flush_gen = 0; /* FUA completed means block is
2329                                               * on disk */
2330                block->is_iodone = 1; /* for FLUSH, this releases the block */
2331                block = next_block;
2332        } while (NULL != block);
2333
2334        bp->bi_end_io(bp, bio_error_status);
2335}
2336
2337static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate)
2338{
2339        struct btrfsic_block *block = (struct btrfsic_block *)bh->b_private;
2340        int iodone_w_error = !uptodate;
2341        struct btrfsic_dev_state *dev_state;
2342
2343        BUG_ON(NULL == block);
2344        dev_state = block->dev_state;
2345        if ((dev_state->state->print_mask & BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2346                printk(KERN_INFO
2347                       "bh_end_io(error=%d) for %c @%llu (%s/%llu/%d)\n",
2348                       iodone_w_error,
2349                       btrfsic_get_block_type(dev_state->state, block),
2350                       (unsigned long long)block->logical_bytenr,
2351                       block->dev_state->name,
2352                       (unsigned long long)block->dev_bytenr,
2353                       block->mirror_num);
2354
2355        block->iodone_w_error = iodone_w_error;
2356        if (block->submit_bio_bh_rw & REQ_FLUSH) {
2357                dev_state->last_flush_gen++;
2358                if ((dev_state->state->print_mask &
2359                     BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2360                        printk(KERN_INFO
2361                               "bh_end_io() new %s flush_gen=%llu\n",
2362                               dev_state->name,
2363                               (unsigned long long)dev_state->last_flush_gen);
2364        }
2365        if (block->submit_bio_bh_rw & REQ_FUA)
2366                block->flush_gen = 0; /* FUA completed means block is on disk */
2367
2368        bh->b_private = block->orig_bio_bh_private;
2369        bh->b_end_io = block->orig_bio_bh_end_io.bh;
2370        block->is_iodone = 1; /* for FLUSH, this releases the block */
2371        bh->b_end_io(bh, uptodate);
2372}
2373
2374static int btrfsic_process_written_superblock(
2375                struct btrfsic_state *state,
2376                struct btrfsic_block *const superblock,
2377                struct btrfs_super_block *const super_hdr)
2378{
2379        int pass;
2380
2381        superblock->generation = btrfs_super_generation(super_hdr);
2382        if (!(superblock->generation > state->max_superblock_generation ||
2383              0 == state->max_superblock_generation)) {
2384                if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2385                        printk(KERN_INFO
2386                               "btrfsic: superblock @%llu (%s/%llu/%d)"
2387                               " with old gen %llu <= %llu\n",
2388                               (unsigned long long)superblock->logical_bytenr,
2389                               superblock->dev_state->name,
2390                               (unsigned long long)superblock->dev_bytenr,
2391                               superblock->mirror_num,
2392                               (unsigned long long)
2393                               btrfs_super_generation(super_hdr),
2394                               (unsigned long long)
2395                               state->max_superblock_generation);
2396        } else {
2397                if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2398                        printk(KERN_INFO
2399                               "btrfsic: got new superblock @%llu (%s/%llu/%d)"
2400                               " with new gen %llu > %llu\n",
2401                               (unsigned long long)superblock->logical_bytenr,
2402                               superblock->dev_state->name,
2403                               (unsigned long long)superblock->dev_bytenr,
2404                               superblock->mirror_num,
2405                               (unsigned long long)
2406                               btrfs_super_generation(super_hdr),
2407                               (unsigned long long)
2408                               state->max_superblock_generation);
2409
2410                state->max_superblock_generation =
2411                    btrfs_super_generation(super_hdr);
2412                state->latest_superblock = superblock;
2413        }
2414
2415        for (pass = 0; pass < 3; pass++) {
2416                int ret;
2417                u64 next_bytenr;
2418                struct btrfsic_block *next_block;
2419                struct btrfsic_block_data_ctx tmp_next_block_ctx;
2420                struct btrfsic_block_link *l;
2421                int num_copies;
2422                int mirror_num;
2423                const char *additional_string = NULL;
2424                struct btrfs_disk_key tmp_disk_key;
2425
2426                tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
2427                tmp_disk_key.offset = 0;
2428
2429                switch (pass) {
2430                case 0:
2431                        tmp_disk_key.objectid =
2432                            cpu_to_le64(BTRFS_ROOT_TREE_OBJECTID);
2433                        additional_string = "root ";
2434                        next_bytenr = btrfs_super_root(super_hdr);
2435                        if (state->print_mask &
2436                            BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2437                                printk(KERN_INFO "root@%llu\n",
2438                                       (unsigned long long)next_bytenr);
2439                        break;
2440                case 1:
2441                        tmp_disk_key.objectid =
2442                            cpu_to_le64(BTRFS_CHUNK_TREE_OBJECTID);
2443                        additional_string = "chunk ";
2444                        next_bytenr = btrfs_super_chunk_root(super_hdr);
2445                        if (state->print_mask &
2446                            BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2447                                printk(KERN_INFO "chunk@%llu\n",
2448                                       (unsigned long long)next_bytenr);
2449                        break;
2450                case 2:
2451                        tmp_disk_key.objectid =
2452                            cpu_to_le64(BTRFS_TREE_LOG_OBJECTID);
2453                        additional_string = "log ";
2454                        next_bytenr = btrfs_super_log_root(super_hdr);
2455                        if (0 == next_bytenr)
2456                                continue;
2457                        if (state->print_mask &
2458                            BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2459                                printk(KERN_INFO "log@%llu\n",
2460                                       (unsigned long long)next_bytenr);
2461                        break;
2462                }
2463
2464                num_copies =
2465                    btrfs_num_copies(&state->root->fs_info->mapping_tree,
2466                                     next_bytenr, BTRFS_SUPER_INFO_SIZE);
2467                if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
2468                        printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
2469                               (unsigned long long)next_bytenr, num_copies);
2470                for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2471                        int was_created;
2472
2473                        if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2474                                printk(KERN_INFO
2475                                       "btrfsic_process_written_superblock("
2476                                       "mirror_num=%d)\n", mirror_num);
2477                        ret = btrfsic_map_block(state, next_bytenr,
2478                                                BTRFS_SUPER_INFO_SIZE,
2479                                                &tmp_next_block_ctx,
2480                                                mirror_num);
2481                        if (ret) {
2482                                printk(KERN_INFO
2483                                       "btrfsic: btrfsic_map_block(@%llu,"
2484                                       " mirror=%d) failed!\n",
2485                                       (unsigned long long)next_bytenr,
2486                                       mirror_num);
2487                                return -1;
2488                        }
2489
2490                        next_block = btrfsic_block_lookup_or_add(
2491                                        state,
2492                                        &tmp_next_block_ctx,
2493                                        additional_string,
2494                                        1, 0, 1,
2495                                        mirror_num,
2496                                        &was_created);
2497                        if (NULL == next_block) {
2498                                printk(KERN_INFO
2499                                       "btrfsic: error, kmalloc failed!\n");
2500                                btrfsic_release_block_ctx(&tmp_next_block_ctx);
2501                                return -1;
2502                        }
2503
2504                        next_block->disk_key = tmp_disk_key;
2505                        if (was_created)
2506                                next_block->generation =
2507                                    BTRFSIC_GENERATION_UNKNOWN;
2508                        l = btrfsic_block_link_lookup_or_add(
2509                                        state,
2510                                        &tmp_next_block_ctx,
2511                                        next_block,
2512                                        superblock,
2513                                        BTRFSIC_GENERATION_UNKNOWN);
2514                        btrfsic_release_block_ctx(&tmp_next_block_ctx);
2515                        if (NULL == l)
2516                                return -1;
2517                }
2518        }
2519
2520        if (-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)) {
2521                WARN_ON(1);
2522                btrfsic_dump_tree(state);
2523        }
2524
2525        return 0;
2526}
2527
2528static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
2529                                        struct btrfsic_block *const block,
2530                                        int recursion_level)
2531{
2532        struct list_head *elem_ref_to;
2533        int ret = 0;
2534
2535        if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2536                /*
2537                 * Note that this situation can happen and does not
2538                 * indicate an error in regular cases. It happens
2539                 * when disk blocks are freed and later reused.
2540                 * The check-integrity module is not aware of any
2541                 * block free operations, it just recognizes block
2542                 * write operations. Therefore it keeps the linkage
2543                 * information for a block until a block is
2544                 * rewritten. This can temporarily cause incorrect
2545                 * and even circular linkage informations. This
2546                 * causes no harm unless such blocks are referenced
2547                 * by the most recent super block.
2548                 */
2549                if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2550                        printk(KERN_INFO
2551                               "btrfsic: abort cyclic linkage (case 1).\n");
2552
2553                return ret;
2554        }
2555
2556        /*
2557         * This algorithm is recursive because the amount of used stack
2558         * space is very small and the max recursion depth is limited.
2559         */
2560        list_for_each(elem_ref_to, &block->ref_to_list) {
2561                const struct btrfsic_block_link *const l =
2562                    list_entry(elem_ref_to, struct btrfsic_block_link,
2563                               node_ref_to);
2564
2565                if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2566                        printk(KERN_INFO
2567                               "rl=%d, %c @%llu (%s/%llu/%d)"
2568                               " %u* refers to %c @%llu (%s/%llu/%d)\n",
2569                               recursion_level,
2570                               btrfsic_get_block_type(state, block),
2571                               (unsigned long long)block->logical_bytenr,
2572                               block->dev_state->name,
2573                               (unsigned long long)block->dev_bytenr,
2574                               block->mirror_num,
2575                               l->ref_cnt,
2576                               btrfsic_get_block_type(state, l->block_ref_to),
2577                               (unsigned long long)
2578                               l->block_ref_to->logical_bytenr,
2579                               l->block_ref_to->dev_state->name,
2580                               (unsigned long long)l->block_ref_to->dev_bytenr,
2581                               l->block_ref_to->mirror_num);
2582                if (l->block_ref_to->never_written) {
2583                        printk(KERN_INFO "btrfs: attempt to write superblock"
2584                               " which references block %c @%llu (%s/%llu/%d)"
2585                               " which is never written!\n",
2586                               btrfsic_get_block_type(state, l->block_ref_to),
2587                               (unsigned long long)
2588                               l->block_ref_to->logical_bytenr,
2589                               l->block_ref_to->dev_state->name,
2590                               (unsigned long long)l->block_ref_to->dev_bytenr,
2591                               l->block_ref_to->mirror_num);
2592                        ret = -1;
2593                } else if (!l->block_ref_to->is_iodone) {
2594                        printk(KERN_INFO "btrfs: attempt to write superblock"
2595                               " which references block %c @%llu (%s/%llu/%d)"
2596                               " which is not yet iodone!\n",
2597                               btrfsic_get_block_type(state, l->block_ref_to),
2598                               (unsigned long long)
2599                               l->block_ref_to->logical_bytenr,
2600                               l->block_ref_to->dev_state->name,
2601                               (unsigned long long)l->block_ref_to->dev_bytenr,
2602                               l->block_ref_to->mirror_num);
2603                        ret = -1;
2604                } else if (l->parent_generation !=
2605                           l->block_ref_to->generation &&
2606                           BTRFSIC_GENERATION_UNKNOWN !=
2607                           l->parent_generation &&
2608                           BTRFSIC_GENERATION_UNKNOWN !=
2609                           l->block_ref_to->generation) {
2610                        printk(KERN_INFO "btrfs: attempt to write superblock"
2611                               " which references block %c @%llu (%s/%llu/%d)"
2612                               " with generation %llu !="
2613                               " parent generation %llu!\n",
2614                               btrfsic_get_block_type(state, l->block_ref_to),
2615                               (unsigned long long)
2616                               l->block_ref_to->logical_bytenr,
2617                               l->block_ref_to->dev_state->name,
2618                               (unsigned long long)l->block_ref_to->dev_bytenr,
2619                               l->block_ref_to->mirror_num,
2620                               (unsigned long long)l->block_ref_to->generation,
2621                               (unsigned long long)l->parent_generation);
2622                        ret = -1;
2623                } else if (l->block_ref_to->flush_gen >
2624                           l->block_ref_to->dev_state->last_flush_gen) {
2625                        printk(KERN_INFO "btrfs: attempt to write superblock"
2626                               " which references block %c @%llu (%s/%llu/%d)"
2627                               " which is not flushed out of disk's write cache"
2628                               " (block flush_gen=%llu,"
2629                               " dev->flush_gen=%llu)!\n",
2630                               btrfsic_get_block_type(state, l->block_ref_to),
2631                               (unsigned long long)
2632                               l->block_ref_to->logical_bytenr,
2633                               l->block_ref_to->dev_state->name,
2634                               (unsigned long long)l->block_ref_to->dev_bytenr,
2635                               l->block_ref_to->mirror_num,
2636                               (unsigned long long)block->flush_gen,
2637                               (unsigned long long)
2638                               l->block_ref_to->dev_state->last_flush_gen);
2639                        ret = -1;
2640                } else if (-1 == btrfsic_check_all_ref_blocks(state,
2641                                                              l->block_ref_to,
2642                                                              recursion_level +
2643                                                              1)) {
2644                        ret = -1;
2645                }
2646        }
2647
2648        return ret;
2649}
2650
2651static int btrfsic_is_block_ref_by_superblock(
2652                const struct btrfsic_state *state,
2653                const struct btrfsic_block *block,
2654                int recursion_level)
2655{
2656        struct list_head *elem_ref_from;
2657
2658        if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2659                /* refer to comment at "abort cyclic linkage (case 1)" */
2660                if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2661                        printk(KERN_INFO
2662                               "btrfsic: abort cyclic linkage (case 2).\n");
2663
2664                return 0;
2665        }
2666
2667        /*
2668         * This algorithm is recursive because the amount of used stack space
2669         * is very small and the max recursion depth is limited.
2670         */
2671        list_for_each(elem_ref_from, &block->ref_from_list) {
2672                const struct btrfsic_block_link *const l =
2673                    list_entry(elem_ref_from, struct btrfsic_block_link,
2674                               node_ref_from);
2675
2676                if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2677                        printk(KERN_INFO
2678                               "rl=%d, %c @%llu (%s/%llu/%d)"
2679                               " is ref %u* from %c @%llu (%s/%llu/%d)\n",
2680                               recursion_level,
2681                               btrfsic_get_block_type(state, block),
2682                               (unsigned long long)block->logical_bytenr,
2683                               block->dev_state->name,
2684                               (unsigned long long)block->dev_bytenr,
2685                               block->mirror_num,
2686                               l->ref_cnt,
2687                               btrfsic_get_block_type(state, l->block_ref_from),
2688                               (unsigned long long)
2689                               l->block_ref_from->logical_bytenr,
2690                               l->block_ref_from->dev_state->name,
2691                               (unsigned long long)
2692                               l->block_ref_from->dev_bytenr,
2693                               l->block_ref_from->mirror_num);
2694                if (l->block_ref_from->is_superblock &&
2695                    state->latest_superblock->dev_bytenr ==
2696                    l->block_ref_from->dev_bytenr &&
2697                    state->latest_superblock->dev_state->bdev ==
2698                    l->block_ref_from->dev_state->bdev)
2699                        return 1;
2700                else if (btrfsic_is_block_ref_by_superblock(state,
2701                                                            l->block_ref_from,
2702                                                            recursion_level +
2703                                                            1))
2704                        return 1;
2705        }
2706
2707        return 0;
2708}
2709
2710static void btrfsic_print_add_link(const struct btrfsic_state *state,
2711                                   const struct btrfsic_block_link *l)
2712{
2713        printk(KERN_INFO
2714               "Add %u* link from %c @%llu (%s/%llu/%d)"
2715               " to %c @%llu (%s/%llu/%d).\n",
2716               l->ref_cnt,
2717               btrfsic_get_block_type(state, l->block_ref_from),
2718               (unsigned long long)l->block_ref_from->logical_bytenr,
2719               l->block_ref_from->dev_state->name,
2720               (unsigned long long)l->block_ref_from->dev_bytenr,
2721               l->block_ref_from->mirror_num,
2722               btrfsic_get_block_type(state, l->block_ref_to),
2723               (unsigned long long)l->block_ref_to->logical_bytenr,
2724               l->block_ref_to->dev_state->name,
2725               (unsigned long long)l->block_ref_to->dev_bytenr,
2726               l->block_ref_to->mirror_num);
2727}
2728
2729static void btrfsic_print_rem_link(const struct btrfsic_state *state,
2730                                   const struct btrfsic_block_link *l)
2731{
2732        printk(KERN_INFO
2733               "Rem %u* link from %c @%llu (%s/%llu/%d)"
2734               " to %c @%llu (%s/%llu/%d).\n",
2735               l->ref_cnt,
2736               btrfsic_get_block_type(state, l->block_ref_from),
2737               (unsigned long long)l->block_ref_from->logical_bytenr,
2738               l->block_ref_from->dev_state->name,
2739               (unsigned long long)l->block_ref_from->dev_bytenr,
2740               l->block_ref_from->mirror_num,
2741               btrfsic_get_block_type(state, l->block_ref_to),
2742               (unsigned long long)l->block_ref_to->logical_bytenr,
2743               l->block_ref_to->dev_state->name,
2744               (unsigned long long)l->block_ref_to->dev_bytenr,
2745               l->block_ref_to->mirror_num);
2746}
2747
2748static char btrfsic_get_block_type(const struct btrfsic_state *state,
2749                                   const struct btrfsic_block *block)
2750{
2751        if (block->is_superblock &&
2752            state->latest_superblock->dev_bytenr == block->dev_bytenr &&
2753            state->latest_superblock->dev_state->bdev == block->dev_state->bdev)
2754                return 'S';
2755        else if (block->is_superblock)
2756                return 's';
2757        else if (block->is_metadata)
2758                return 'M';
2759        else
2760                return 'D';
2761}
2762
2763static void btrfsic_dump_tree(const struct btrfsic_state *state)
2764{
2765        btrfsic_dump_tree_sub(state, state->latest_superblock, 0);
2766}
2767
2768static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
2769                                  const struct btrfsic_block *block,
2770                                  int indent_level)
2771{
2772        struct list_head *elem_ref_to;
2773        int indent_add;
2774        static char buf[80];
2775        int cursor_position;
2776
2777        /*
2778         * Should better fill an on-stack buffer with a complete line and
2779         * dump it at once when it is time to print a newline character.
2780         */
2781
2782        /*
2783         * This algorithm is recursive because the amount of used stack space
2784         * is very small and the max recursion depth is limited.
2785         */
2786        indent_add = sprintf(buf, "%c-%llu(%s/%llu/%d)",
2787                             btrfsic_get_block_type(state, block),
2788                             (unsigned long long)block->logical_bytenr,
2789                             block->dev_state->name,
2790                             (unsigned long long)block->dev_bytenr,
2791                             block->mirror_num);
2792        if (indent_level + indent_add > BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2793                printk("[...]\n");
2794                return;
2795        }
2796        printk(buf);
2797        indent_level += indent_add;
2798        if (list_empty(&block->ref_to_list)) {
2799                printk("\n");
2800                return;
2801        }
2802        if (block->mirror_num > 1 &&
2803            !(state->print_mask & BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS)) {
2804                printk(" [...]\n");
2805                return;
2806        }
2807
2808        cursor_position = indent_level;
2809        list_for_each(elem_ref_to, &block->ref_to_list) {
2810                const struct btrfsic_block_link *const l =
2811                    list_entry(elem_ref_to, struct btrfsic_block_link,
2812                               node_ref_to);
2813
2814                while (cursor_position < indent_level) {
2815                        printk(" ");
2816                        cursor_position++;
2817                }
2818                if (l->ref_cnt > 1)
2819                        indent_add = sprintf(buf, " %d*--> ", l->ref_cnt);
2820                else
2821                        indent_add = sprintf(buf, " --> ");
2822                if (indent_level + indent_add >
2823                    BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2824                        printk("[...]\n");
2825                        cursor_position = 0;
2826                        continue;
2827                }
2828
2829                printk(buf);
2830
2831                btrfsic_dump_tree_sub(state, l->block_ref_to,
2832                                      indent_level + indent_add);
2833                cursor_position = 0;
2834        }
2835}
2836
2837static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
2838                struct btrfsic_state *state,
2839                struct btrfsic_block_data_ctx *next_block_ctx,
2840                struct btrfsic_block *next_block,
2841                struct btrfsic_block *from_block,
2842                u64 parent_generation)
2843{
2844        struct btrfsic_block_link *l;
2845
2846        l = btrfsic_block_link_hashtable_lookup(next_block_ctx->dev->bdev,
2847                                                next_block_ctx->dev_bytenr,
2848                                                from_block->dev_state->bdev,
2849                                                from_block->dev_bytenr,
2850                                                &state->block_link_hashtable);
2851        if (NULL == l) {
2852                l = btrfsic_block_link_alloc();
2853                if (NULL == l) {
2854                        printk(KERN_INFO
2855                               "btrfsic: error, kmalloc" " failed!\n");
2856                        return NULL;
2857                }
2858
2859                l->block_ref_to = next_block;
2860                l->block_ref_from = from_block;
2861                l->ref_cnt = 1;
2862                l->parent_generation = parent_generation;
2863
2864                if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2865                        btrfsic_print_add_link(state, l);
2866
2867                list_add(&l->node_ref_to, &from_block->ref_to_list);
2868                list_add(&l->node_ref_from, &next_block->ref_from_list);
2869
2870                btrfsic_block_link_hashtable_add(l,
2871                                                 &state->block_link_hashtable);
2872        } else {
2873                l->ref_cnt++;
2874                l->parent_generation = parent_generation;
2875                if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2876                        btrfsic_print_add_link(state, l);
2877        }
2878
2879        return l;
2880}
2881
2882static struct btrfsic_block *btrfsic_block_lookup_or_add(
2883                struct btrfsic_state *state,
2884                struct btrfsic_block_data_ctx *block_ctx,
2885                const char *additional_string,
2886                int is_metadata,
2887                int is_iodone,
2888                int never_written,
2889                int mirror_num,
2890                int *was_created)
2891{
2892        struct btrfsic_block *block;
2893
2894        block = btrfsic_block_hashtable_lookup(block_ctx->dev->bdev,
2895                                               block_ctx->dev_bytenr,
2896                                               &state->block_hashtable);
2897        if (NULL == block) {
2898                struct btrfsic_dev_state *dev_state;
2899
2900                block = btrfsic_block_alloc();
2901                if (NULL == block) {
2902                        printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2903                        return NULL;
2904                }
2905                dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev);
2906                if (NULL == dev_state) {
2907                        printk(KERN_INFO
2908                               "btrfsic: error, lookup dev_state failed!\n");
2909                        btrfsic_block_free(block);
2910                        return NULL;
2911                }
2912                block->dev_state = dev_state;
2913                block->dev_bytenr = block_ctx->dev_bytenr;
2914                block->logical_bytenr = block_ctx->start;
2915                block->is_metadata = is_metadata;
2916                block->is_iodone = is_iodone;
2917                block->never_written = never_written;
2918                block->mirror_num = mirror_num;
2919                if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2920                        printk(KERN_INFO
2921                               "New %s%c-block @%llu (%s/%llu/%d)\n",
2922                               additional_string,
2923                               btrfsic_get_block_type(state, block),
2924                               (unsigned long long)block->logical_bytenr,
2925                               dev_state->name,
2926                               (unsigned long long)block->dev_bytenr,
2927                               mirror_num);
2928                list_add(&block->all_blocks_node, &state->all_blocks_list);
2929                btrfsic_block_hashtable_add(block, &state->block_hashtable);
2930                if (NULL != was_created)
2931                        *was_created = 1;
2932        } else {
2933                if (NULL != was_created)
2934                        *was_created = 0;
2935        }
2936
2937        return block;
2938}
2939
2940static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
2941                                           u64 bytenr,
2942                                           struct btrfsic_dev_state *dev_state,
2943                                           u64 dev_bytenr)
2944{
2945        int num_copies;
2946        int mirror_num;
2947        int ret;
2948        struct btrfsic_block_data_ctx block_ctx;
2949        int match = 0;
2950
2951        num_copies = btrfs_num_copies(&state->root->fs_info->mapping_tree,
2952                                      bytenr, state->metablock_size);
2953
2954        for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2955                ret = btrfsic_map_block(state, bytenr, state->metablock_size,
2956                                        &block_ctx, mirror_num);
2957                if (ret) {
2958                        printk(KERN_INFO "btrfsic:"
2959                               " btrfsic_map_block(logical @%llu,"
2960                               " mirror %d) failed!\n",
2961                               (unsigned long long)bytenr, mirror_num);
2962                        continue;
2963                }
2964
2965                if (dev_state->bdev == block_ctx.dev->bdev &&
2966                    dev_bytenr == block_ctx.dev_bytenr) {
2967                        match++;
2968                        btrfsic_release_block_ctx(&block_ctx);
2969                        break;
2970                }
2971                btrfsic_release_block_ctx(&block_ctx);
2972        }
2973
2974        if (!match) {
2975                printk(KERN_INFO "btrfs: attempt to write M-block which contains logical bytenr that doesn't map to dev+physical bytenr of submit_bio,"
2976                       " buffer->log_bytenr=%llu, submit_bio(bdev=%s,"
2977                       " phys_bytenr=%llu)!\n",
2978                       (unsigned long long)bytenr, dev_state->name,
2979                       (unsigned long long)dev_bytenr);
2980                for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2981                        ret = btrfsic_map_block(state, bytenr,
2982                                                state->metablock_size,
2983                                                &block_ctx, mirror_num);
2984                        if (ret)
2985                                continue;
2986
2987                        printk(KERN_INFO "Read logical bytenr @%llu maps to"
2988                               " (%s/%llu/%d)\n",
2989                               (unsigned long long)bytenr,
2990                               block_ctx.dev->name,
2991                               (unsigned long long)block_ctx.dev_bytenr,
2992                               mirror_num);
2993                }
2994                WARN_ON(1);
2995        }
2996}
2997
2998static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
2999                struct block_device *bdev)
3000{
3001        struct btrfsic_dev_state *ds;
3002
3003        ds = btrfsic_dev_state_hashtable_lookup(bdev,
3004                                                &btrfsic_dev_state_hashtable);
3005        return ds;
3006}
3007
3008int btrfsic_submit_bh(int rw, struct buffer_head *bh)
3009{
3010        struct btrfsic_dev_state *dev_state;
3011
3012        if (!btrfsic_is_initialized)
3013                return submit_bh(rw, bh);
3014
3015        mutex_lock(&btrfsic_mutex);
3016        /* since btrfsic_submit_bh() might also be called before
3017         * btrfsic_mount(), this might return NULL */
3018        dev_state = btrfsic_dev_state_lookup(bh->b_bdev);
3019
3020        /* Only called to write the superblock (incl. FLUSH/FUA) */
3021        if (NULL != dev_state &&
3022            (rw & WRITE) && bh->b_size > 0) {
3023                u64 dev_bytenr;
3024
3025                dev_bytenr = 4096 * bh->b_blocknr;
3026                if (dev_state->state->print_mask &
3027                    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3028                        printk(KERN_INFO
3029                               "submit_bh(rw=0x%x, blocknr=%lu (bytenr %llu),"
3030                               " size=%lu, data=%p, bdev=%p)\n",
3031                               rw, (unsigned long)bh->b_blocknr,
3032                               (unsigned long long)dev_bytenr,
3033                               (unsigned long)bh->b_size, bh->b_data,
3034                               bh->b_bdev);
3035                btrfsic_process_written_block(dev_state, dev_bytenr,
3036                                              &bh->b_data, 1, NULL,
3037                                              NULL, bh, rw);
3038        } else if (NULL != dev_state && (rw & REQ_FLUSH)) {
3039                if (dev_state->state->print_mask &
3040                    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3041                        printk(KERN_INFO
3042                               "submit_bh(rw=0x%x FLUSH, bdev=%p)\n",
3043                               rw, bh->b_bdev);
3044                if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
3045                        if ((dev_state->state->print_mask &
3046                             (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3047                              BTRFSIC_PRINT_MASK_VERBOSE)))
3048                                printk(KERN_INFO
3049                                       "btrfsic_submit_bh(%s) with FLUSH"
3050                                       " but dummy block already in use"
3051                                       " (ignored)!\n",
3052                                       dev_state->name);
3053                } else {
3054                        struct btrfsic_block *const block =
3055                                &dev_state->dummy_block_for_bio_bh_flush;
3056
3057                        block->is_iodone = 0;
3058                        block->never_written = 0;
3059                        block->iodone_w_error = 0;
3060                        block->flush_gen = dev_state->last_flush_gen + 1;
3061                        block->submit_bio_bh_rw = rw;
3062                        block->orig_bio_bh_private = bh->b_private;
3063                        block->orig_bio_bh_end_io.bh = bh->b_end_io;
3064                        block->next_in_same_bio = NULL;
3065                        bh->b_private = block;
3066                        bh->b_end_io = btrfsic_bh_end_io;
3067                }
3068        }
3069        mutex_unlock(&btrfsic_mutex);
3070        return submit_bh(rw, bh);
3071}
3072
3073void btrfsic_submit_bio(int rw, struct bio *bio)
3074{
3075        struct btrfsic_dev_state *dev_state;
3076
3077        if (!btrfsic_is_initialized) {
3078                submit_bio(rw, bio);
3079                return;
3080        }
3081
3082        mutex_lock(&btrfsic_mutex);
3083        /* since btrfsic_submit_bio() is also called before
3084         * btrfsic_mount(), this might return NULL */
3085        dev_state = btrfsic_dev_state_lookup(bio->bi_bdev);
3086        if (NULL != dev_state &&
3087            (rw & WRITE) && NULL != bio->bi_io_vec) {
3088                unsigned int i;
3089                u64 dev_bytenr;
3090                int bio_is_patched;
3091                char **mapped_datav;
3092
3093                dev_bytenr = 512 * bio->bi_sector;
3094                bio_is_patched = 0;
3095                if (dev_state->state->print_mask &
3096                    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3097                        printk(KERN_INFO
3098                               "submit_bio(rw=0x%x, bi_vcnt=%u,"
3099                               " bi_sector=%lu (bytenr %llu), bi_bdev=%p)\n",
3100                               rw, bio->bi_vcnt, (unsigned long)bio->bi_sector,
3101                               (unsigned long long)dev_bytenr,
3102                               bio->bi_bdev);
3103
3104                mapped_datav = kmalloc(sizeof(*mapped_datav) * bio->bi_vcnt,
3105                                       GFP_NOFS);
3106                if (!mapped_datav)
3107                        goto leave;
3108                for (i = 0; i < bio->bi_vcnt; i++) {
3109                        BUG_ON(bio->bi_io_vec[i].bv_len != PAGE_CACHE_SIZE);
3110                        mapped_datav[i] = kmap(bio->bi_io_vec[i].bv_page);
3111                        if (!mapped_datav[i]) {
3112                                while (i > 0) {
3113                                        i--;
3114                                        kunmap(bio->bi_io_vec[i].bv_page);
3115                                }
3116                                kfree(mapped_datav);
3117                                goto leave;
3118                        }
3119                        if ((BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3120                             BTRFSIC_PRINT_MASK_VERBOSE) ==
3121                            (dev_state->state->print_mask &
3122                             (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3123                              BTRFSIC_PRINT_MASK_VERBOSE)))
3124                                printk(KERN_INFO
3125                                       "#%u: page=%p, len=%u, offset=%u\n",
3126                                       i, bio->bi_io_vec[i].bv_page,
3127                                       bio->bi_io_vec[i].bv_len,
3128                                       bio->bi_io_vec[i].bv_offset);
3129                }
3130                btrfsic_process_written_block(dev_state, dev_bytenr,
3131                                              mapped_datav, bio->bi_vcnt,
3132                                              bio, &bio_is_patched,
3133                                              NULL, rw);
3134                while (i > 0) {
3135                        i--;
3136                        kunmap(bio->bi_io_vec[i].bv_page);
3137                }
3138                kfree(mapped_datav);
3139        } else if (NULL != dev_state && (rw & REQ_FLUSH)) {
3140                if (dev_state->state->print_mask &
3141                    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3142                        printk(KERN_INFO
3143                               "submit_bio(rw=0x%x FLUSH, bdev=%p)\n",
3144                               rw, bio->bi_bdev);
3145                if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
3146                        if ((dev_state->state->print_mask &
3147                             (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3148                              BTRFSIC_PRINT_MASK_VERBOSE)))
3149                                printk(KERN_INFO
3150                                       "btrfsic_submit_bio(%s) with FLUSH"
3151                                       " but dummy block already in use"
3152                                       " (ignored)!\n",
3153                                       dev_state->name);
3154                } else {
3155                        struct btrfsic_block *const block =
3156                                &dev_state->dummy_block_for_bio_bh_flush;
3157
3158                        block->is_iodone = 0;
3159                        block->never_written = 0;
3160                        block->iodone_w_error = 0;
3161                        block->flush_gen = dev_state->last_flush_gen + 1;
3162                        block->submit_bio_bh_rw = rw;
3163                        block->orig_bio_bh_private = bio->bi_private;
3164                        block->orig_bio_bh_end_io.bio = bio->bi_end_io;
3165                        block->next_in_same_bio = NULL;
3166                        bio->bi_private = block;
3167                        bio->bi_end_io = btrfsic_bio_end_io;
3168                }
3169        }
3170leave:
3171        mutex_unlock(&btrfsic_mutex);
3172
3173        submit_bio(rw, bio);
3174}
3175
3176int btrfsic_mount(struct btrfs_root *root,
3177                  struct btrfs_fs_devices *fs_devices,
3178                  int including_extent_data, u32 print_mask)
3179{
3180        int ret;
3181        struct btrfsic_state *state;
3182        struct list_head *dev_head = &fs_devices->devices;
3183        struct btrfs_device *device;
3184
3185        if (root->nodesize != root->leafsize) {
3186                printk(KERN_INFO
3187                       "btrfsic: cannot handle nodesize %d != leafsize %d!\n",
3188                       root->nodesize, root->leafsize);
3189                return -1;
3190        }
3191        if (root->nodesize & ((u64)PAGE_CACHE_SIZE - 1)) {
3192                printk(KERN_INFO
3193                       "btrfsic: cannot handle nodesize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3194                       root->nodesize, (unsigned long)PAGE_CACHE_SIZE);
3195                return -1;
3196        }
3197        if (root->leafsize & ((u64)PAGE_CACHE_SIZE - 1)) {
3198                printk(KERN_INFO
3199                       "btrfsic: cannot handle leafsize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3200                       root->leafsize, (unsigned long)PAGE_CACHE_SIZE);
3201                return -1;
3202        }
3203        if (root->sectorsize & ((u64)PAGE_CACHE_SIZE - 1)) {
3204                printk(KERN_INFO
3205                       "btrfsic: cannot handle sectorsize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3206                       root->sectorsize, (unsigned long)PAGE_CACHE_SIZE);
3207                return -1;
3208        }
3209        state = kzalloc(sizeof(*state), GFP_NOFS);
3210        if (NULL == state) {
3211                printk(KERN_INFO "btrfs check-integrity: kmalloc() failed!\n");
3212                return -1;
3213        }
3214
3215        if (!btrfsic_is_initialized) {
3216                mutex_init(&btrfsic_mutex);
3217                btrfsic_dev_state_hashtable_init(&btrfsic_dev_state_hashtable);
3218                btrfsic_is_initialized = 1;
3219        }
3220        mutex_lock(&btrfsic_mutex);
3221        state->root = root;
3222        state->print_mask = print_mask;
3223        state->include_extent_data = including_extent_data;
3224        state->csum_size = 0;
3225        state->metablock_size = root->nodesize;
3226        state->datablock_size = root->sectorsize;
3227        INIT_LIST_HEAD(&state->all_blocks_list);
3228        btrfsic_block_hashtable_init(&state->block_hashtable);
3229        btrfsic_block_link_hashtable_init(&state->block_link_hashtable);
3230        state->max_superblock_generation = 0;
3231        state->latest_superblock = NULL;
3232
3233        list_for_each_entry(device, dev_head, dev_list) {
3234                struct btrfsic_dev_state *ds;
3235                char *p;
3236
3237                if (!device->bdev || !device->name)
3238                        continue;
3239
3240                ds = btrfsic_dev_state_alloc();
3241                if (NULL == ds) {
3242                        printk(KERN_INFO
3243                               "btrfs check-integrity: kmalloc() failed!\n");
3244                        mutex_unlock(&btrfsic_mutex);
3245                        return -1;
3246                }
3247                ds->bdev = device->bdev;
3248                ds->state = state;
3249                bdevname(ds->bdev, ds->name);
3250                ds->name[BDEVNAME_SIZE - 1] = '\0';
3251                for (p = ds->name; *p != '\0'; p++);
3252                while (p > ds->name && *p != '/')
3253                        p--;
3254                if (*p == '/')
3255                        p++;
3256                strlcpy(ds->name, p, sizeof(ds->name));
3257                btrfsic_dev_state_hashtable_add(ds,
3258                                                &btrfsic_dev_state_hashtable);
3259        }
3260
3261        ret = btrfsic_process_superblock(state, fs_devices);
3262        if (0 != ret) {
3263                mutex_unlock(&btrfsic_mutex);
3264                btrfsic_unmount(root, fs_devices);
3265                return ret;
3266        }
3267
3268        if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_DATABASE)
3269                btrfsic_dump_database(state);
3270        if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_TREE)
3271                btrfsic_dump_tree(state);
3272
3273        mutex_unlock(&btrfsic_mutex);
3274        return 0;
3275}
3276
3277void btrfsic_unmount(struct btrfs_root *root,
3278                     struct btrfs_fs_devices *fs_devices)
3279{
3280        struct list_head *elem_all;
3281        struct list_head *tmp_all;
3282        struct btrfsic_state *state;
3283        struct list_head *dev_head = &fs_devices->devices;
3284        struct btrfs_device *device;
3285
3286        if (!btrfsic_is_initialized)
3287                return;
3288
3289        mutex_lock(&btrfsic_mutex);
3290
3291        state = NULL;
3292        list_for_each_entry(device, dev_head, dev_list) {
3293                struct btrfsic_dev_state *ds;
3294
3295                if (!device->bdev || !device->name)
3296                        continue;
3297
3298                ds = btrfsic_dev_state_hashtable_lookup(
3299                                device->bdev,
3300                                &btrfsic_dev_state_hashtable);
3301                if (NULL != ds) {
3302                        state = ds->state;
3303                        btrfsic_dev_state_hashtable_remove(ds);
3304                        btrfsic_dev_state_free(ds);
3305                }
3306        }
3307
3308        if (NULL == state) {
3309                printk(KERN_INFO
3310                       "btrfsic: error, cannot find state information"
3311                       " on umount!\n");
3312                mutex_unlock(&btrfsic_mutex);
3313                return;
3314        }
3315
3316        /*
3317         * Don't care about keeping the lists' state up to date,
3318         * just free all memory that was allocated dynamically.
3319         * Free the blocks and the block_links.
3320         */
3321        list_for_each_safe(elem_all, tmp_all, &state->all_blocks_list) {
3322                struct btrfsic_block *const b_all =
3323                    list_entry(elem_all, struct btrfsic_block,
3324                               all_blocks_node);
3325                struct list_head *elem_ref_to;
3326                struct list_head *tmp_ref_to;
3327
3328                list_for_each_safe(elem_ref_to, tmp_ref_to,
3329                                   &b_all->ref_to_list) {
3330                        struct btrfsic_block_link *const l =
3331                            list_entry(elem_ref_to,
3332                                       struct btrfsic_block_link,
3333                                       node_ref_to);
3334
3335                        if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
3336                                btrfsic_print_rem_link(state, l);
3337
3338                        l->ref_cnt--;
3339                        if (0 == l->ref_cnt)
3340                                btrfsic_block_link_free(l);
3341                }
3342
3343                if (b_all->is_iodone || b_all->never_written)
3344                        btrfsic_block_free(b_all);
3345                else
3346                        printk(KERN_INFO "btrfs: attempt to free %c-block"
3347                               " @%llu (%s/%llu/%d) on umount which is"
3348                               " not yet iodone!\n",
3349                               btrfsic_get_block_type(state, b_all),
3350                               (unsigned long long)b_all->logical_bytenr,
3351                               b_all->dev_state->name,
3352                               (unsigned long long)b_all->dev_bytenr,
3353                               b_all->mirror_num);
3354        }
3355
3356        mutex_unlock(&btrfsic_mutex);
3357
3358        kfree(state);
3359}
3360
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