fs/btrfs/check-integrity.c

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