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/crc32c.h>
  96 #include <linux/genhd.h>
  97 #include <linux/blkdev.h>
  98 #include "ctree.h"
  99 #include "disk-io.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->total_bytes)
 811                 return -1;
 812         bh = __bread(superblock_bdev, dev_bytenr / 4096,
 813                      BTRFS_SUPER_INFO_SIZE);
 814         if (NULL == bh)
 815                 return -1;
 816         super_tmp = (struct btrfs_super_block *)
 817             (bh->b_data + (dev_bytenr & 4095));
 818
 819         if (btrfs_super_bytenr(super_tmp) != dev_bytenr ||
 820             btrfs_super_magic(super_tmp) != BTRFS_MAGIC ||
 821             memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE) ||
 822             btrfs_super_nodesize(super_tmp) != state->metablock_size ||
 823             btrfs_super_leafsize(super_tmp) != state->metablock_size ||
 824             btrfs_super_sectorsize(super_tmp) != state->datablock_size) {
 825                 brelse(bh);
 826                 return 0;
 827         }
 828
 829         superblock_tmp =
 830             btrfsic_block_hashtable_lookup(superblock_bdev,
 831                                            dev_bytenr,
 832                                            &state->block_hashtable);
 833         if (NULL == superblock_tmp) {
 834                 superblock_tmp = btrfsic_block_alloc();
 835                 if (NULL == superblock_tmp) {
 836                         printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
 837                         brelse(bh);
 838                         return -1;
 839                 }
 840                 /* for superblock, only the dev_bytenr makes sense */
 841                 superblock_tmp->dev_bytenr = dev_bytenr;
 842                 superblock_tmp->dev_state = dev_state;
 843                 superblock_tmp->logical_bytenr = dev_bytenr;
 844                 superblock_tmp->generation = btrfs_super_generation(super_tmp);
 845                 superblock_tmp->is_metadata = 1;
 846                 superblock_tmp->is_superblock = 1;
 847                 superblock_tmp->is_iodone = 1;
 848                 superblock_tmp->never_written = 0;
 849                 superblock_tmp->mirror_num = 1 + superblock_mirror_num;
 850                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
 851                         printk_in_rcu(KERN_INFO "New initial S-block (bdev %p, %s)"
 852                                      " @%llu (%s/%llu/%d)\n",
 853                                      superblock_bdev,
 854                                      rcu_str_deref(device->name), dev_bytenr,
 855                                      dev_state->name, dev_bytenr,
 856                                      superblock_mirror_num);
 857                 list_add(&superblock_tmp->all_blocks_node,
 858                          &state->all_blocks_list);
 859                 btrfsic_block_hashtable_add(superblock_tmp,
 860                                             &state->block_hashtable);
 861         }
 862
 863         /* select the one with the highest generation field */
 864         if (btrfs_super_generation(super_tmp) >
 865             state->max_superblock_generation ||
 866             0 == state->max_superblock_generation) {
 867                 memcpy(selected_super, super_tmp, sizeof(*selected_super));
 868                 *selected_dev_state = dev_state;
 869                 state->max_superblock_generation =
 870                     btrfs_super_generation(super_tmp);
 871                 state->latest_superblock = superblock_tmp;
 872         }
 873
 874         for (pass = 0; pass < 3; pass++) {
 875                 u64 next_bytenr;
 876                 int num_copies;
 877                 int mirror_num;
 878                 const char *additional_string = NULL;
 879                 struct btrfs_disk_key tmp_disk_key;
 880
 881                 tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
 882                 tmp_disk_key.offset = 0;
 883                 switch (pass) {
 884                 case 0:
 885                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 886                                                     BTRFS_ROOT_TREE_OBJECTID);
 887                         additional_string = "initial root ";
 888                         next_bytenr = btrfs_super_root(super_tmp);
 889                         break;
 890                 case 1:
 891                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 892                                                     BTRFS_CHUNK_TREE_OBJECTID);
 893                         additional_string = "initial chunk ";
 894                         next_bytenr = btrfs_super_chunk_root(super_tmp);
 895                         break;
 896                 case 2:
 897                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 898                                                     BTRFS_TREE_LOG_OBJECTID);
 899                         additional_string = "initial log ";
 900                         next_bytenr = btrfs_super_log_root(super_tmp);
 901                         if (0 == next_bytenr)
 902                                 continue;
 903                         break;
 904                 }
 905
 906                 num_copies =
 907                     btrfs_num_copies(state->root->fs_info,
 908                                      next_bytenr, state->metablock_size);
 909                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 910                         printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
 911                                next_bytenr, num_copies);
 912                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 913                         struct btrfsic_block *next_block;
 914                         struct btrfsic_block_data_ctx tmp_next_block_ctx;
 915                         struct btrfsic_block_link *l;
 916
 917                         if (btrfsic_map_block(state, next_bytenr,
 918                                               state->metablock_size,
 919                                               &tmp_next_block_ctx,
 920                                               mirror_num)) {
 921                                 printk(KERN_INFO "btrfsic: btrfsic_map_block("
 922                                        "bytenr @%llu, mirror %d) failed!\n",
 923                                        next_bytenr, mirror_num);
 924                                 brelse(bh);
 925                                 return -1;
 926                         }
 927
 928                         next_block = btrfsic_block_lookup_or_add(
 929                                         state, &tmp_next_block_ctx,
 930                                         additional_string, 1, 1, 0,
 931                                         mirror_num, NULL);
 932                         if (NULL == next_block) {
 933                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
 934                                 brelse(bh);
 935                                 return -1;
 936                         }
 937
 938                         next_block->disk_key = tmp_disk_key;
 939                         next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
 940                         l = btrfsic_block_link_lookup_or_add(
 941                                         state, &tmp_next_block_ctx,
 942                                         next_block, superblock_tmp,
 943                                         BTRFSIC_GENERATION_UNKNOWN);
 944                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
 945                         if (NULL == l) {
 946                                 brelse(bh);
 947                                 return -1;
 948                         }
 949                 }
 950         }
 951         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES)
 952                 btrfsic_dump_tree_sub(state, superblock_tmp, 0);
 953
 954         brelse(bh);
 955         return 0;
 956 }
 957
 958 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void)
 959 {
 960         struct btrfsic_stack_frame *sf;
 961
 962         sf = kzalloc(sizeof(*sf), GFP_NOFS);
 963         if (NULL == sf)
 964                 printk(KERN_INFO "btrfsic: alloc memory failed!\n");
 965         else
 966                 sf->magic = BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER;
 967         return sf;
 968 }
 969
 970 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf)
 971 {
 972         BUG_ON(!(NULL == sf ||
 973                  BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER == sf->magic));
 974         kfree(sf);
 975 }
 976
 977 static int btrfsic_process_metablock(
 978                 struct btrfsic_state *state,
 979                 struct btrfsic_block *const first_block,
 980                 struct btrfsic_block_data_ctx *const first_block_ctx,
 981                 int first_limit_nesting, int force_iodone_flag)
 982 {
 983         struct btrfsic_stack_frame initial_stack_frame = { 0 };
 984         struct btrfsic_stack_frame *sf;
 985         struct btrfsic_stack_frame *next_stack;
 986         struct btrfs_header *const first_hdr =
 987                 (struct btrfs_header *)first_block_ctx->datav[0];
 988
 989         BUG_ON(!first_hdr);
 990         sf = &initial_stack_frame;
 991         sf->error = 0;
 992         sf->i = -1;
 993         sf->limit_nesting = first_limit_nesting;
 994         sf->block = first_block;
 995         sf->block_ctx = first_block_ctx;
 996         sf->next_block = NULL;
 997         sf->hdr = first_hdr;
 998         sf->prev = NULL;
 999
1000 continue_with_new_stack_frame:
1001         sf->block->generation = le64_to_cpu(sf->hdr->generation);
1002         if (0 == sf->hdr->level) {
1003                 struct btrfs_leaf *const leafhdr =
1004                     (struct btrfs_leaf *)sf->hdr;
1005
1006                 if (-1 == sf->i) {
1007                         sf->nr = btrfs_stack_header_nritems(&leafhdr->header);
1008
1009                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1010                                 printk(KERN_INFO
1011                                        "leaf %llu items %d generation %llu"
1012                                        " owner %llu\n",
1013                                        sf->block_ctx->start, sf->nr,
1014                                        btrfs_stack_header_generation(
1015                                                &leafhdr->header),
1016                                        btrfs_stack_header_owner(
1017                                                &leafhdr->header));
1018                 }
1019
1020 continue_with_current_leaf_stack_frame:
1021                 if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1022                         sf->i++;
1023                         sf->num_copies = 0;
1024                 }
1025
1026                 if (sf->i < sf->nr) {
1027                         struct btrfs_item disk_item;
1028                         u32 disk_item_offset =
1029                                 (uintptr_t)(leafhdr->items + sf->i) -
1030                                 (uintptr_t)leafhdr;
1031                         struct btrfs_disk_key *disk_key;
1032                         u8 type;
1033                         u32 item_offset;
1034                         u32 item_size;
1035
1036                         if (disk_item_offset + sizeof(struct btrfs_item) >
1037                             sf->block_ctx->len) {
1038 leaf_item_out_of_bounce_error:
1039                                 printk(KERN_INFO
1040                                        "btrfsic: leaf item out of bounce at logical %llu, dev %s\n",
1041                                        sf->block_ctx->start,
1042                                        sf->block_ctx->dev->name);
1043                                 goto one_stack_frame_backwards;
1044                         }
1045                         btrfsic_read_from_block_data(sf->block_ctx,
1046                                                      &disk_item,
1047                                                      disk_item_offset,
1048                                                      sizeof(struct btrfs_item));
1049                         item_offset = btrfs_stack_item_offset(&disk_item);
1050                         item_size = btrfs_stack_item_size(&disk_item);
1051                         disk_key = &disk_item.key;
1052                         type = btrfs_disk_key_type(disk_key);
1053
1054                         if (BTRFS_ROOT_ITEM_KEY == type) {
1055                                 struct btrfs_root_item root_item;
1056                                 u32 root_item_offset;
1057                                 u64 next_bytenr;
1058
1059                                 root_item_offset = item_offset +
1060                                         offsetof(struct btrfs_leaf, items);
1061                                 if (root_item_offset + item_size >
1062                                     sf->block_ctx->len)
1063                                         goto leaf_item_out_of_bounce_error;
1064                                 btrfsic_read_from_block_data(
1065                                         sf->block_ctx, &root_item,
1066                                         root_item_offset,
1067                                         item_size);
1068                                 next_bytenr = btrfs_root_bytenr(&root_item);
1069
1070                                 sf->error =
1071                                     btrfsic_create_link_to_next_block(
1072                                                 state,
1073                                                 sf->block,
1074                                                 sf->block_ctx,
1075                                                 next_bytenr,
1076                                                 sf->limit_nesting,
1077                                                 &sf->next_block_ctx,
1078                                                 &sf->next_block,
1079                                                 force_iodone_flag,
1080                                                 &sf->num_copies,
1081                                                 &sf->mirror_num,
1082                                                 disk_key,
1083                                                 btrfs_root_generation(
1084                                                 &root_item));
1085                                 if (sf->error)
1086                                         goto one_stack_frame_backwards;
1087
1088                                 if (NULL != sf->next_block) {
1089                                         struct btrfs_header *const next_hdr =
1090                                             (struct btrfs_header *)
1091                                             sf->next_block_ctx.datav[0];
1092
1093                                         next_stack =
1094                                             btrfsic_stack_frame_alloc();
1095                                         if (NULL == next_stack) {
1096                                                 btrfsic_release_block_ctx(
1097                                                                 &sf->
1098                                                                 next_block_ctx);
1099                                                 goto one_stack_frame_backwards;
1100                                         }
1101
1102                                         next_stack->i = -1;
1103                                         next_stack->block = sf->next_block;
1104                                         next_stack->block_ctx =
1105                                             &sf->next_block_ctx;
1106                                         next_stack->next_block = NULL;
1107                                         next_stack->hdr = next_hdr;
1108                                         next_stack->limit_nesting =
1109                                             sf->limit_nesting - 1;
1110                                         next_stack->prev = sf;
1111                                         sf = next_stack;
1112                                         goto continue_with_new_stack_frame;
1113                                 }
1114                         } else if (BTRFS_EXTENT_DATA_KEY == type &&
1115                                    state->include_extent_data) {
1116                                 sf->error = btrfsic_handle_extent_data(
1117                                                 state,
1118                                                 sf->block,
1119                                                 sf->block_ctx,
1120                                                 item_offset,
1121                                                 force_iodone_flag);
1122                                 if (sf->error)
1123                                         goto one_stack_frame_backwards;
1124                         }
1125
1126                         goto continue_with_current_leaf_stack_frame;
1127                 }
1128         } else {
1129                 struct btrfs_node *const nodehdr = (struct btrfs_node *)sf->hdr;
1130
1131                 if (-1 == sf->i) {
1132                         sf->nr = btrfs_stack_header_nritems(&nodehdr->header);
1133
1134                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1135                                 printk(KERN_INFO "node %llu level %d items %d"
1136                                        " generation %llu owner %llu\n",
1137                                        sf->block_ctx->start,
1138                                        nodehdr->header.level, sf->nr,
1139                                        btrfs_stack_header_generation(
1140                                        &nodehdr->header),
1141                                        btrfs_stack_header_owner(
1142                                        &nodehdr->header));
1143                 }
1144
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                                         goto one_stack_frame_backwards;
1195
1196                                 next_stack->i = -1;
1197                                 next_stack->block = sf->next_block;
1198                                 next_stack->block_ctx = &sf->next_block_ctx;
1199                                 next_stack->next_block = NULL;
1200                                 next_stack->hdr = next_hdr;
1201                                 next_stack->limit_nesting =
1202                                     sf->limit_nesting - 1;
1203                                 next_stack->prev = sf;
1204                                 sf = next_stack;
1205                                 goto continue_with_new_stack_frame;
1206                         }
1207
1208                         goto continue_with_current_node_stack_frame;
1209                 }
1210         }
1211
1212 one_stack_frame_backwards:
1213         if (NULL != sf->prev) {
1214                 struct btrfsic_stack_frame *const prev = sf->prev;
1215
1216                 /* the one for the initial block is freed in the caller */
1217                 btrfsic_release_block_ctx(sf->block_ctx);
1218
1219                 if (sf->error) {
1220                         prev->error = sf->error;
1221                         btrfsic_stack_frame_free(sf);
1222                         sf = prev;
1223                         goto one_stack_frame_backwards;
1224                 }
1225
1226                 btrfsic_stack_frame_free(sf);
1227                 sf = prev;
1228                 goto continue_with_new_stack_frame;
1229         } else {
1230                 BUG_ON(&initial_stack_frame != sf);
1231         }
1232
1233         return sf->error;
1234 }
1235
1236 static void btrfsic_read_from_block_data(
1237         struct btrfsic_block_data_ctx *block_ctx,
1238         void *dstv, u32 offset, size_t len)
1239 {
1240         size_t cur;
1241         size_t offset_in_page;
1242         char *kaddr;
1243         char *dst = (char *)dstv;
1244         size_t start_offset = block_ctx->start & ((u64)PAGE_CACHE_SIZE - 1);
1245         unsigned long i = (start_offset + offset) >> PAGE_CACHE_SHIFT;
1246
1247         WARN_ON(offset + len > block_ctx->len);
1248         offset_in_page = (start_offset + offset) & (PAGE_CACHE_SIZE - 1);
1249
1250         while (len > 0) {
1251                 cur = min(len, ((size_t)PAGE_CACHE_SIZE - offset_in_page));
1252                 BUG_ON(i >= (block_ctx->len + PAGE_CACHE_SIZE - 1) >>
1253                             PAGE_CACHE_SHIFT);
1254                 kaddr = block_ctx->datav[i];
1255                 memcpy(dst, kaddr + offset_in_page, cur);
1256
1257                 dst += cur;
1258                 len -= cur;
1259                 offset_in_page = 0;
1260                 i++;
1261         }
1262 }
1263
1264 static int btrfsic_create_link_to_next_block(
1265                 struct btrfsic_state *state,
1266                 struct btrfsic_block *block,
1267                 struct btrfsic_block_data_ctx *block_ctx,
1268                 u64 next_bytenr,
1269                 int limit_nesting,
1270                 struct btrfsic_block_data_ctx *next_block_ctx,
1271                 struct btrfsic_block **next_blockp,
1272                 int force_iodone_flag,
1273                 int *num_copiesp, int *mirror_nump,
1274                 struct btrfs_disk_key *disk_key,
1275                 u64 parent_generation)
1276 {
1277         struct btrfsic_block *next_block = NULL;
1278         int ret;
1279         struct btrfsic_block_link *l;
1280         int did_alloc_block_link;
1281         int block_was_created;
1282
1283         *next_blockp = NULL;
1284         if (0 == *num_copiesp) {
1285                 *num_copiesp =
1286                     btrfs_num_copies(state->root->fs_info,
1287                                      next_bytenr, state->metablock_size);
1288                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1289                         printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1290                                next_bytenr, *num_copiesp);
1291                 *mirror_nump = 1;
1292         }
1293
1294         if (*mirror_nump > *num_copiesp)
1295                 return 0;
1296
1297         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1298                 printk(KERN_INFO
1299                        "btrfsic_create_link_to_next_block(mirror_num=%d)\n",
1300                        *mirror_nump);
1301         ret = btrfsic_map_block(state, next_bytenr,
1302                                 state->metablock_size,
1303                                 next_block_ctx, *mirror_nump);
1304         if (ret) {
1305                 printk(KERN_INFO
1306                        "btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1307                        next_bytenr, *mirror_nump);
1308                 btrfsic_release_block_ctx(next_block_ctx);
1309                 *next_blockp = NULL;
1310                 return -1;
1311         }
1312
1313         next_block = btrfsic_block_lookup_or_add(state,
1314                                                  next_block_ctx, "referenced ",
1315                                                  1, force_iodone_flag,
1316                                                  !force_iodone_flag,
1317                                                  *mirror_nump,
1318                                                  &block_was_created);
1319         if (NULL == next_block) {
1320                 btrfsic_release_block_ctx(next_block_ctx);
1321                 *next_blockp = NULL;
1322                 return -1;
1323         }
1324         if (block_was_created) {
1325                 l = NULL;
1326                 next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
1327         } else {
1328                 if (next_block->logical_bytenr != next_bytenr &&
1329                     !(!next_block->is_metadata &&
1330                       0 == next_block->logical_bytenr)) {
1331                         printk(KERN_INFO
1332                                "Referenced block @%llu (%s/%llu/%d)"
1333                                " found in hash table, %c,"
1334                                " bytenr mismatch (!= stored %llu).\n",
1335                                next_bytenr, next_block_ctx->dev->name,
1336                                next_block_ctx->dev_bytenr, *mirror_nump,
1337                                btrfsic_get_block_type(state, next_block),
1338                                next_block->logical_bytenr);
1339                 } else if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1340                         printk(KERN_INFO
1341                                "Referenced block @%llu (%s/%llu/%d)"
1342                                " found in hash table, %c.\n",
1343                                next_bytenr, next_block_ctx->dev->name,
1344                                next_block_ctx->dev_bytenr, *mirror_nump,
1345                                btrfsic_get_block_type(state, next_block));
1346                 next_block->logical_bytenr = next_bytenr;
1347
1348                 next_block->mirror_num = *mirror_nump;
1349                 l = btrfsic_block_link_hashtable_lookup(
1350                                 next_block_ctx->dev->bdev,
1351                                 next_block_ctx->dev_bytenr,
1352                                 block_ctx->dev->bdev,
1353                                 block_ctx->dev_bytenr,
1354                                 &state->block_link_hashtable);
1355         }
1356
1357         next_block->disk_key = *disk_key;
1358         if (NULL == l) {
1359                 l = btrfsic_block_link_alloc();
1360                 if (NULL == l) {
1361                         printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
1362                         btrfsic_release_block_ctx(next_block_ctx);
1363                         *next_blockp = NULL;
1364                         return -1;
1365                 }
1366
1367                 did_alloc_block_link = 1;
1368                 l->block_ref_to = next_block;
1369                 l->block_ref_from = block;
1370                 l->ref_cnt = 1;
1371                 l->parent_generation = parent_generation;
1372
1373                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1374                         btrfsic_print_add_link(state, l);
1375
1376                 list_add(&l->node_ref_to, &block->ref_to_list);
1377                 list_add(&l->node_ref_from, &next_block->ref_from_list);
1378
1379                 btrfsic_block_link_hashtable_add(l,
1380                                                  &state->block_link_hashtable);
1381         } else {
1382                 did_alloc_block_link = 0;
1383                 if (0 == limit_nesting) {
1384                         l->ref_cnt++;
1385                         l->parent_generation = parent_generation;
1386                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1387                                 btrfsic_print_add_link(state, l);
1388                 }
1389         }
1390
1391         if (limit_nesting > 0 && did_alloc_block_link) {
1392                 ret = btrfsic_read_block(state, next_block_ctx);
1393                 if (ret < (int)next_block_ctx->len) {
1394                         printk(KERN_INFO
1395                                "btrfsic: read block @logical %llu failed!\n",
1396                                next_bytenr);
1397                         btrfsic_release_block_ctx(next_block_ctx);
1398                         *next_blockp = NULL;
1399                         return -1;
1400                 }
1401
1402                 *next_blockp = next_block;
1403         } else {
1404                 *next_blockp = NULL;
1405         }
1406         (*mirror_nump)++;
1407
1408         return 0;
1409 }
1410
1411 static int btrfsic_handle_extent_data(
1412                 struct btrfsic_state *state,
1413                 struct btrfsic_block *block,
1414                 struct btrfsic_block_data_ctx *block_ctx,
1415                 u32 item_offset, int force_iodone_flag)
1416 {
1417         int ret;
1418         struct btrfs_file_extent_item file_extent_item;
1419         u64 file_extent_item_offset;
1420         u64 next_bytenr;
1421         u64 num_bytes;
1422         u64 generation;
1423         struct btrfsic_block_link *l;
1424
1425         file_extent_item_offset = offsetof(struct btrfs_leaf, items) +
1426                                   item_offset;
1427         if (file_extent_item_offset +
1428             offsetof(struct btrfs_file_extent_item, disk_num_bytes) >
1429             block_ctx->len) {
1430                 printk(KERN_INFO
1431                        "btrfsic: file item out of bounce at logical %llu, dev %s\n",
1432                        block_ctx->start, block_ctx->dev->name);
1433                 return -1;
1434         }
1435
1436         btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1437                 file_extent_item_offset,
1438                 offsetof(struct btrfs_file_extent_item, disk_num_bytes));
1439         if (BTRFS_FILE_EXTENT_REG != file_extent_item.type ||
1440             btrfs_stack_file_extent_disk_bytenr(&file_extent_item) == 0) {
1441                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1442                         printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu\n",
1443                                file_extent_item.type,
1444                                btrfs_stack_file_extent_disk_bytenr(
1445                                &file_extent_item));
1446                 return 0;
1447         }
1448
1449         if (file_extent_item_offset + sizeof(struct btrfs_file_extent_item) >
1450             block_ctx->len) {
1451                 printk(KERN_INFO
1452                        "btrfsic: file item out of bounce at logical %llu, dev %s\n",
1453                        block_ctx->start, block_ctx->dev->name);
1454                 return -1;
1455         }
1456         btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1457                                      file_extent_item_offset,
1458                                      sizeof(struct btrfs_file_extent_item));
1459         next_bytenr = btrfs_stack_file_extent_disk_bytenr(&file_extent_item) +
1460                       btrfs_stack_file_extent_offset(&file_extent_item);
1461         generation = btrfs_stack_file_extent_generation(&file_extent_item);
1462         num_bytes = btrfs_stack_file_extent_num_bytes(&file_extent_item);
1463         generation = btrfs_stack_file_extent_generation(&file_extent_item);
1464
1465         if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1466                 printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu,"
1467                        " offset = %llu, num_bytes = %llu\n",
1468                        file_extent_item.type,
1469                        btrfs_stack_file_extent_disk_bytenr(&file_extent_item),
1470                        btrfs_stack_file_extent_offset(&file_extent_item),
1471                        num_bytes);
1472         while (num_bytes > 0) {
1473                 u32 chunk_len;
1474                 int num_copies;
1475                 int mirror_num;
1476
1477                 if (num_bytes > state->datablock_size)
1478                         chunk_len = state->datablock_size;
1479                 else
1480                         chunk_len = num_bytes;
1481
1482                 num_copies =
1483                     btrfs_num_copies(state->root->fs_info,
1484                                      next_bytenr, state->datablock_size);
1485                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1486                         printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1487                                next_bytenr, num_copies);
1488                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
1489                         struct btrfsic_block_data_ctx next_block_ctx;
1490                         struct btrfsic_block *next_block;
1491                         int block_was_created;
1492
1493                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1494                                 printk(KERN_INFO "btrfsic_handle_extent_data("
1495                                        "mirror_num=%d)\n", mirror_num);
1496                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1497                                 printk(KERN_INFO
1498                                        "\tdisk_bytenr = %llu, num_bytes %u\n",
1499                                        next_bytenr, chunk_len);
1500                         ret = btrfsic_map_block(state, next_bytenr,
1501                                                 chunk_len, &next_block_ctx,
1502                                                 mirror_num);
1503                         if (ret) {
1504                                 printk(KERN_INFO
1505                                        "btrfsic: btrfsic_map_block(@%llu,"
1506                                        " mirror=%d) failed!\n",
1507                                        next_bytenr, mirror_num);
1508                                 return -1;
1509                         }
1510
1511                         next_block = btrfsic_block_lookup_or_add(
1512                                         state,
1513                                         &next_block_ctx,
1514                                         "referenced ",
1515                                         0,
1516                                         force_iodone_flag,
1517                                         !force_iodone_flag,
1518                                         mirror_num,
1519                                         &block_was_created);
1520                         if (NULL == next_block) {
1521                                 printk(KERN_INFO
1522                                        "btrfsic: error, kmalloc failed!\n");
1523                                 btrfsic_release_block_ctx(&next_block_ctx);
1524                                 return -1;
1525                         }
1526                         if (!block_was_created) {
1527                                 if (next_block->logical_bytenr != next_bytenr &&
1528                                     !(!next_block->is_metadata &&
1529                                       0 == next_block->logical_bytenr)) {
1530                                         printk(KERN_INFO
1531                                                "Referenced block"
1532                                                " @%llu (%s/%llu/%d)"
1533                                                " found in hash table, D,"
1534                                                " bytenr mismatch"
1535                                                " (!= stored %llu).\n",
1536                                                next_bytenr,
1537                                                next_block_ctx.dev->name,
1538                                                next_block_ctx.dev_bytenr,
1539                                                mirror_num,
1540                                                next_block->logical_bytenr);
1541                                 }
1542                                 next_block->logical_bytenr = next_bytenr;
1543                                 next_block->mirror_num = mirror_num;
1544                         }
1545
1546                         l = btrfsic_block_link_lookup_or_add(state,
1547                                                              &next_block_ctx,
1548                                                              next_block, block,
1549                                                              generation);
1550                         btrfsic_release_block_ctx(&next_block_ctx);
1551                         if (NULL == l)
1552                                 return -1;
1553                 }
1554
1555                 next_bytenr += chunk_len;
1556                 num_bytes -= chunk_len;
1557         }
1558
1559         return 0;
1560 }
1561
1562 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
1563                              struct btrfsic_block_data_ctx *block_ctx_out,
1564                              int mirror_num)
1565 {
1566         int ret;
1567         u64 length;
1568         struct btrfs_bio *multi = NULL;
1569         struct btrfs_device *device;
1570
1571         length = len;
1572         ret = btrfs_map_block(state->root->fs_info, READ,
1573                               bytenr, &length, &multi, mirror_num);
1574
1575         if (ret) {
1576                 block_ctx_out->start = 0;
1577                 block_ctx_out->dev_bytenr = 0;
1578                 block_ctx_out->len = 0;
1579                 block_ctx_out->dev = NULL;
1580                 block_ctx_out->datav = NULL;
1581                 block_ctx_out->pagev = NULL;
1582                 block_ctx_out->mem_to_free = NULL;
1583
1584                 return ret;
1585         }
1586
1587         device = multi->stripes[0].dev;
1588         block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev);
1589         block_ctx_out->dev_bytenr = multi->stripes[0].physical;
1590         block_ctx_out->start = bytenr;
1591         block_ctx_out->len = len;
1592         block_ctx_out->datav = NULL;
1593         block_ctx_out->pagev = NULL;
1594         block_ctx_out->mem_to_free = NULL;
1595
1596         kfree(multi);
1597         if (NULL == block_ctx_out->dev) {
1598                 ret = -ENXIO;
1599                 printk(KERN_INFO "btrfsic: error, cannot lookup dev (#1)!\n");
1600         }
1601
1602         return ret;
1603 }
1604
1605 static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
1606                                   u32 len, struct block_device *bdev,
1607                                   struct btrfsic_block_data_ctx *block_ctx_out)
1608 {
1609         block_ctx_out->dev = btrfsic_dev_state_lookup(bdev);
1610         block_ctx_out->dev_bytenr = bytenr;
1611         block_ctx_out->start = bytenr;
1612         block_ctx_out->len = len;
1613         block_ctx_out->datav = NULL;
1614         block_ctx_out->pagev = NULL;
1615         block_ctx_out->mem_to_free = NULL;
1616         if (NULL != block_ctx_out->dev) {
1617                 return 0;
1618         } else {
1619                 printk(KERN_INFO "btrfsic: error, cannot lookup dev (#2)!\n");
1620                 return -ENXIO;
1621         }
1622 }
1623
1624 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
1625 {
1626         if (block_ctx->mem_to_free) {
1627                 unsigned int num_pages;
1628
1629                 BUG_ON(!block_ctx->datav);
1630                 BUG_ON(!block_ctx->pagev);
1631                 num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
1632                             PAGE_CACHE_SHIFT;
1633                 while (num_pages > 0) {
1634                         num_pages--;
1635                         if (block_ctx->datav[num_pages]) {
1636                                 kunmap(block_ctx->pagev[num_pages]);
1637                                 block_ctx->datav[num_pages] = NULL;
1638                         }
1639                         if (block_ctx->pagev[num_pages]) {
1640                                 __free_page(block_ctx->pagev[num_pages]);
1641                                 block_ctx->pagev[num_pages] = NULL;
1642                         }
1643                 }
1644
1645                 kfree(block_ctx->mem_to_free);
1646                 block_ctx->mem_to_free = NULL;
1647                 block_ctx->pagev = NULL;
1648                 block_ctx->datav = NULL;
1649         }
1650 }
1651
1652 static int btrfsic_read_block(struct btrfsic_state *state,
1653                               struct btrfsic_block_data_ctx *block_ctx)
1654 {
1655         unsigned int num_pages;
1656         unsigned int i;
1657         u64 dev_bytenr;
1658         int ret;
1659
1660         BUG_ON(block_ctx->datav);
1661         BUG_ON(block_ctx->pagev);
1662         BUG_ON(block_ctx->mem_to_free);
1663         if (block_ctx->dev_bytenr & ((u64)PAGE_CACHE_SIZE - 1)) {
1664                 printk(KERN_INFO
1665                        "btrfsic: read_block() with unaligned bytenr %llu\n",
1666                        block_ctx->dev_bytenr);
1667                 return -1;
1668         }
1669
1670         num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
1671                     PAGE_CACHE_SHIFT;
1672         block_ctx->mem_to_free = kzalloc((sizeof(*block_ctx->datav) +
1673                                           sizeof(*block_ctx->pagev)) *
1674                                          num_pages, GFP_NOFS);
1675         if (!block_ctx->mem_to_free)
1676                 return -1;
1677         block_ctx->datav = block_ctx->mem_to_free;
1678         block_ctx->pagev = (struct page **)(block_ctx->datav + num_pages);
1679         for (i = 0; i < num_pages; i++) {
1680                 block_ctx->pagev[i] = alloc_page(GFP_NOFS);
1681                 if (!block_ctx->pagev[i])
1682                         return -1;
1683         }
1684
1685         dev_bytenr = block_ctx->dev_bytenr;
1686         for (i = 0; i < num_pages;) {
1687                 struct bio *bio;
1688                 unsigned int j;
1689
1690                 bio = btrfs_io_bio_alloc(GFP_NOFS, num_pages - i);
1691                 if (!bio) {
1692                         printk(KERN_INFO
1693                                "btrfsic: bio_alloc() for %u pages failed!\n",
1694                                num_pages - i);
1695                         return -1;
1696                 }
1697                 bio->bi_bdev = block_ctx->dev->bdev;
1698                 bio->bi_sector = dev_bytenr >> 9;
1699
1700                 for (j = i; j < num_pages; j++) {
1701                         ret = bio_add_page(bio, block_ctx->pagev[j],
1702                                            PAGE_CACHE_SIZE, 0);
1703                         if (PAGE_CACHE_SIZE != ret)
1704                                 break;
1705                 }
1706                 if (j == i) {
1707                         printk(KERN_INFO
1708                                "btrfsic: error, failed to add a single page!\n");
1709                         return -1;
1710                 }
1711                 if (submit_bio_wait(READ, bio)) {
1712                         printk(KERN_INFO
1713                                "btrfsic: read error at logical %llu dev %s!\n",
1714                                block_ctx->start, block_ctx->dev->name);
1715                         bio_put(bio);
1716                         return -1;
1717                 }
1718                 bio_put(bio);
1719                 dev_bytenr += (j - i) * PAGE_CACHE_SIZE;
1720                 i = j;
1721         }
1722         for (i = 0; i < num_pages; i++) {
1723                 block_ctx->datav[i] = kmap(block_ctx->pagev[i]);
1724                 if (!block_ctx->datav[i]) {
1725                         printk(KERN_INFO "btrfsic: kmap() failed (dev %s)!\n",
1726                                block_ctx->dev->name);
1727                         return -1;
1728                 }
1729         }
1730
1731         return block_ctx->len;
1732 }
1733
1734 static void btrfsic_dump_database(struct btrfsic_state *state)
1735 {
1736         struct list_head *elem_all;
1737
1738         BUG_ON(NULL == state);
1739
1740         printk(KERN_INFO "all_blocks_list:\n");
1741         list_for_each(elem_all, &state->all_blocks_list) {
1742                 const struct btrfsic_block *const b_all =
1743                     list_entry(elem_all, struct btrfsic_block,
1744                                all_blocks_node);
1745                 struct list_head *elem_ref_to;
1746                 struct list_head *elem_ref_from;
1747
1748                 printk(KERN_INFO "%c-block @%llu (%s/%llu/%d)\n",
1749                        btrfsic_get_block_type(state, b_all),
1750                        b_all->logical_bytenr, b_all->dev_state->name,
1751                        b_all->dev_bytenr, b_all->mirror_num);
1752
1753                 list_for_each(elem_ref_to, &b_all->ref_to_list) {
1754                         const struct btrfsic_block_link *const l =
1755                             list_entry(elem_ref_to,
1756                                        struct btrfsic_block_link,
1757                                        node_ref_to);
1758
1759                         printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1760                                " refers %u* to"
1761                                " %c @%llu (%s/%llu/%d)\n",
1762                                btrfsic_get_block_type(state, b_all),
1763                                b_all->logical_bytenr, b_all->dev_state->name,
1764                                b_all->dev_bytenr, b_all->mirror_num,
1765                                l->ref_cnt,
1766                                btrfsic_get_block_type(state, l->block_ref_to),
1767                                l->block_ref_to->logical_bytenr,
1768                                l->block_ref_to->dev_state->name,
1769                                l->block_ref_to->dev_bytenr,
1770                                l->block_ref_to->mirror_num);
1771                 }
1772
1773                 list_for_each(elem_ref_from, &b_all->ref_from_list) {
1774                         const struct btrfsic_block_link *const l =
1775                             list_entry(elem_ref_from,
1776                                        struct btrfsic_block_link,
1777                                        node_ref_from);
1778
1779                         printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1780                                " is ref %u* from"
1781                                " %c @%llu (%s/%llu/%d)\n",
1782                                btrfsic_get_block_type(state, b_all),
1783                                b_all->logical_bytenr, b_all->dev_state->name,
1784                                b_all->dev_bytenr, b_all->mirror_num,
1785                                l->ref_cnt,
1786                                btrfsic_get_block_type(state, l->block_ref_from),
1787                                l->block_ref_from->logical_bytenr,
1788                                l->block_ref_from->dev_state->name,
1789                                l->block_ref_from->dev_bytenr,
1790                                l->block_ref_from->mirror_num);
1791                 }
1792
1793                 printk(KERN_INFO "\n");
1794         }
1795 }
1796
1797 /*
1798  * Test whether the disk block contains a tree block (leaf or node)
1799  * (note that this test fails for the super block)
1800  */
1801 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
1802                                      char **datav, unsigned int num_pages)
1803 {
1804         struct btrfs_header *h;
1805         u8 csum[BTRFS_CSUM_SIZE];
1806         u32 crc = ~(u32)0;
1807         unsigned int i;
1808
1809         if (num_pages * PAGE_CACHE_SIZE < state->metablock_size)
1810                 return 1; /* not metadata */
1811         num_pages = state->metablock_size >> PAGE_CACHE_SHIFT;
1812         h = (struct btrfs_header *)datav[0];
1813
1814         if (memcmp(h->fsid, state->root->fs_info->fsid, BTRFS_UUID_SIZE))
1815                 return 1;
1816
1817         for (i = 0; i < num_pages; i++) {
1818                 u8 *data = i ? datav[i] : (datav[i] + BTRFS_CSUM_SIZE);
1819                 size_t sublen = i ? PAGE_CACHE_SIZE :
1820                                     (PAGE_CACHE_SIZE - BTRFS_CSUM_SIZE);
1821
1822                 crc = crc32c(crc, data, sublen);
1823         }
1824         btrfs_csum_final(crc, csum);
1825         if (memcmp(csum, h->csum, state->csum_size))
1826                 return 1;
1827
1828         return 0; /* is metadata */
1829 }
1830
1831 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
1832                                           u64 dev_bytenr, char **mapped_datav,
1833                                           unsigned int num_pages,
1834                                           struct bio *bio, int *bio_is_patched,
1835                                           struct buffer_head *bh,
1836                                           int submit_bio_bh_rw)
1837 {
1838         int is_metadata;
1839         struct btrfsic_block *block;
1840         struct btrfsic_block_data_ctx block_ctx;
1841         int ret;
1842         struct btrfsic_state *state = dev_state->state;
1843         struct block_device *bdev = dev_state->bdev;
1844         unsigned int processed_len;
1845
1846         if (NULL != bio_is_patched)
1847                 *bio_is_patched = 0;
1848
1849 again:
1850         if (num_pages == 0)
1851                 return;
1852
1853         processed_len = 0;
1854         is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_datav,
1855                                                       num_pages));
1856
1857         block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
1858                                                &state->block_hashtable);
1859         if (NULL != block) {
1860                 u64 bytenr = 0;
1861                 struct list_head *elem_ref_to;
1862                 struct list_head *tmp_ref_to;
1863
1864                 if (block->is_superblock) {
1865                         bytenr = btrfs_super_bytenr((struct btrfs_super_block *)
1866                                                     mapped_datav[0]);
1867                         if (num_pages * PAGE_CACHE_SIZE <
1868                             BTRFS_SUPER_INFO_SIZE) {
1869                                 printk(KERN_INFO
1870                                        "btrfsic: cannot work with too short bios!\n");
1871                                 return;
1872                         }
1873                         is_metadata = 1;
1874                         BUG_ON(BTRFS_SUPER_INFO_SIZE & (PAGE_CACHE_SIZE - 1));
1875                         processed_len = BTRFS_SUPER_INFO_SIZE;
1876                         if (state->print_mask &
1877                             BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
1878                                 printk(KERN_INFO
1879                                        "[before new superblock is written]:\n");
1880                                 btrfsic_dump_tree_sub(state, block, 0);
1881                         }
1882                 }
1883                 if (is_metadata) {
1884                         if (!block->is_superblock) {
1885                                 if (num_pages * PAGE_CACHE_SIZE <
1886                                     state->metablock_size) {
1887                                         printk(KERN_INFO
1888                                                "btrfsic: cannot work with too short bios!\n");
1889                                         return;
1890                                 }
1891                                 processed_len = state->metablock_size;
1892                                 bytenr = btrfs_stack_header_bytenr(
1893                                                 (struct btrfs_header *)
1894                                                 mapped_datav[0]);
1895                                 btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
1896                                                                dev_state,
1897                                                                dev_bytenr);
1898                         }
1899                         if (block->logical_bytenr != bytenr &&
1900                             !(!block->is_metadata &&
1901                               block->logical_bytenr == 0))
1902                                 printk(KERN_INFO
1903                                        "Written block @%llu (%s/%llu/%d)"
1904                                        " found in hash table, %c,"
1905                                        " bytenr mismatch"
1906                                        " (!= stored %llu).\n",
1907                                        bytenr, dev_state->name, dev_bytenr,
1908                                        block->mirror_num,
1909                                        btrfsic_get_block_type(state, block),
1910                                        block->logical_bytenr);
1911                         else if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1912                                 printk(KERN_INFO
1913                                        "Written block @%llu (%s/%llu/%d)"
1914                                        " found in hash table, %c.\n",
1915                                        bytenr, dev_state->name, dev_bytenr,
1916                                        block->mirror_num,
1917                                        btrfsic_get_block_type(state, block));
1918                         block->logical_bytenr = bytenr;
1919                 } else {
1920                         if (num_pages * PAGE_CACHE_SIZE <
1921                             state->datablock_size) {
1922                                 printk(KERN_INFO
1923                                        "btrfsic: cannot work with too short bios!\n");
1924                                 return;
1925                         }
1926                         processed_len = state->datablock_size;
1927                         bytenr = block->logical_bytenr;
1928                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1929                                 printk(KERN_INFO
1930                                        "Written block @%llu (%s/%llu/%d)"
1931                                        " found in hash table, %c.\n",
1932                                        bytenr, dev_state->name, dev_bytenr,
1933                                        block->mirror_num,
1934                                        btrfsic_get_block_type(state, block));
1935                 }
1936
1937                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1938                         printk(KERN_INFO
1939                                "ref_to_list: %cE, ref_from_list: %cE\n",
1940                                list_empty(&block->ref_to_list) ? ' ' : '!',
1941                                list_empty(&block->ref_from_list) ? ' ' : '!');
1942                 if (btrfsic_is_block_ref_by_superblock(state, block, 0)) {
1943                         printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
1944                                " @%llu (%s/%llu/%d), old(gen=%llu,"
1945                                " objectid=%llu, type=%d, offset=%llu),"
1946                                " new(gen=%llu),"
1947                                " which is referenced by most recent superblock"
1948                                " (superblockgen=%llu)!\n",
1949                                btrfsic_get_block_type(state, block), bytenr,
1950                                dev_state->name, dev_bytenr, block->mirror_num,
1951                                block->generation,
1952                                btrfs_disk_key_objectid(&block->disk_key),
1953                                block->disk_key.type,
1954                                btrfs_disk_key_offset(&block->disk_key),
1955                                btrfs_stack_header_generation(
1956                                        (struct btrfs_header *) mapped_datav[0]),
1957                                state->max_superblock_generation);
1958                         btrfsic_dump_tree(state);
1959                 }
1960
1961                 if (!block->is_iodone && !block->never_written) {
1962                         printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
1963                                " @%llu (%s/%llu/%d), oldgen=%llu, newgen=%llu,"
1964                                " which is not yet iodone!\n",
1965                                btrfsic_get_block_type(state, block), bytenr,
1966                                dev_state->name, dev_bytenr, block->mirror_num,
1967                                block->generation,
1968                                btrfs_stack_header_generation(
1969                                        (struct btrfs_header *)
1970                                        mapped_datav[0]));
1971                         /* it would not be safe to go on */
1972                         btrfsic_dump_tree(state);
1973                         goto continue_loop;
1974                 }
1975
1976                 /*
1977                  * Clear all references of this block. Do not free
1978                  * the block itself even if is not referenced anymore
1979                  * because it still carries valueable information
1980                  * like whether it was ever written and IO completed.
1981                  */
1982                 list_for_each_safe(elem_ref_to, tmp_ref_to,
1983                                    &block->ref_to_list) {
1984                         struct btrfsic_block_link *const l =
1985                             list_entry(elem_ref_to,
1986                                        struct btrfsic_block_link,
1987                                        node_ref_to);
1988
1989                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1990                                 btrfsic_print_rem_link(state, l);
1991                         l->ref_cnt--;
1992                         if (0 == l->ref_cnt) {
1993                                 list_del(&l->node_ref_to);
1994                                 list_del(&l->node_ref_from);
1995                                 btrfsic_block_link_hashtable_remove(l);
1996                                 btrfsic_block_link_free(l);
1997                         }
1998                 }
1999
2000                 if (block->is_superblock)
2001                         ret = btrfsic_map_superblock(state, bytenr,
2002                                                      processed_len,
2003                                                      bdev, &block_ctx);
2004                 else
2005                         ret = btrfsic_map_block(state, bytenr, processed_len,
2006                                                 &block_ctx, 0);
2007                 if (ret) {
2008                         printk(KERN_INFO
2009                                "btrfsic: btrfsic_map_block(root @%llu)"
2010                                " failed!\n", bytenr);
2011                         goto continue_loop;
2012                 }
2013                 block_ctx.datav = mapped_datav;
2014                 /* the following is required in case of writes to mirrors,
2015                  * use the same that was used for the lookup */
2016                 block_ctx.dev = dev_state;
2017                 block_ctx.dev_bytenr = dev_bytenr;
2018
2019                 if (is_metadata || state->include_extent_data) {
2020                         block->never_written = 0;
2021                         block->iodone_w_error = 0;
2022                         if (NULL != bio) {
2023                                 block->is_iodone = 0;
2024                                 BUG_ON(NULL == bio_is_patched);
2025                                 if (!*bio_is_patched) {
2026                                         block->orig_bio_bh_private =
2027                                             bio->bi_private;
2028                                         block->orig_bio_bh_end_io.bio =
2029                                             bio->bi_end_io;
2030                                         block->next_in_same_bio = NULL;
2031                                         bio->bi_private = block;
2032                                         bio->bi_end_io = btrfsic_bio_end_io;
2033                                         *bio_is_patched = 1;
2034                                 } else {
2035                                         struct btrfsic_block *chained_block =
2036                                             (struct btrfsic_block *)
2037                                             bio->bi_private;
2038
2039                                         BUG_ON(NULL == chained_block);
2040                                         block->orig_bio_bh_private =
2041                                             chained_block->orig_bio_bh_private;
2042                                         block->orig_bio_bh_end_io.bio =
2043                                             chained_block->orig_bio_bh_end_io.
2044                                             bio;
2045                                         block->next_in_same_bio = chained_block;
2046                                         bio->bi_private = block;
2047                                 }
2048                         } else if (NULL != bh) {
2049                                 block->is_iodone = 0;
2050                                 block->orig_bio_bh_private = bh->b_private;
2051                                 block->orig_bio_bh_end_io.bh = bh->b_end_io;
2052                                 block->next_in_same_bio = NULL;
2053                                 bh->b_private = block;
2054                                 bh->b_end_io = btrfsic_bh_end_io;
2055                         } else {
2056                                 block->is_iodone = 1;
2057                                 block->orig_bio_bh_private = NULL;
2058                                 block->orig_bio_bh_end_io.bio = NULL;
2059                                 block->next_in_same_bio = NULL;
2060                         }
2061                 }
2062
2063                 block->flush_gen = dev_state->last_flush_gen + 1;
2064                 block->submit_bio_bh_rw = submit_bio_bh_rw;
2065                 if (is_metadata) {
2066                         block->logical_bytenr = bytenr;
2067                         block->is_metadata = 1;
2068                         if (block->is_superblock) {
2069                                 BUG_ON(PAGE_CACHE_SIZE !=
2070                                        BTRFS_SUPER_INFO_SIZE);
2071                                 ret = btrfsic_process_written_superblock(
2072                                                 state,
2073                                                 block,
2074                                                 (struct btrfs_super_block *)
2075                                                 mapped_datav[0]);
2076                                 if (state->print_mask &
2077                                     BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE) {
2078                                         printk(KERN_INFO
2079                                         "[after new superblock is written]:\n");
2080                                         btrfsic_dump_tree_sub(state, block, 0);
2081                                 }
2082                         } else {
2083                                 block->mirror_num = 0;  /* unknown */
2084                                 ret = btrfsic_process_metablock(
2085                                                 state,
2086                                                 block,
2087                                                 &block_ctx,
2088                                                 0, 0);
2089                         }
2090                         if (ret)
2091                                 printk(KERN_INFO
2092                                        "btrfsic: btrfsic_process_metablock"
2093                                        "(root @%llu) failed!\n",
2094                                        dev_bytenr);
2095                 } else {
2096                         block->is_metadata = 0;
2097                         block->mirror_num = 0;  /* unknown */
2098                         block->generation = BTRFSIC_GENERATION_UNKNOWN;
2099                         if (!state->include_extent_data
2100                             && list_empty(&block->ref_from_list)) {
2101                                 /*
2102                                  * disk block is overwritten with extent
2103                                  * data (not meta data) and we are configured
2104                                  * to not include extent data: take the
2105                                  * chance and free the block's memory
2106                                  */
2107                                 btrfsic_block_hashtable_remove(block);
2108                                 list_del(&block->all_blocks_node);
2109                                 btrfsic_block_free(block);
2110                         }
2111                 }
2112                 btrfsic_release_block_ctx(&block_ctx);
2113         } else {
2114                 /* block has not been found in hash table */
2115                 u64 bytenr;
2116
2117                 if (!is_metadata) {
2118                         processed_len = state->datablock_size;
2119                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2120                                 printk(KERN_INFO "Written block (%s/%llu/?)"
2121                                        " !found in hash table, D.\n",
2122                                        dev_state->name, dev_bytenr);
2123                         if (!state->include_extent_data) {
2124                                 /* ignore that written D block */
2125                                 goto continue_loop;
2126                         }
2127
2128                         /* this is getting ugly for the
2129                          * include_extent_data case... */
2130                         bytenr = 0;     /* unknown */
2131                         block_ctx.start = bytenr;
2132                         block_ctx.len = processed_len;
2133                         block_ctx.mem_to_free = NULL;
2134                         block_ctx.pagev = NULL;
2135                 } else {
2136                         processed_len = state->metablock_size;
2137                         bytenr = btrfs_stack_header_bytenr(
2138                                         (struct btrfs_header *)
2139                                         mapped_datav[0]);
2140                         btrfsic_cmp_log_and_dev_bytenr(state, bytenr, dev_state,
2141                                                        dev_bytenr);
2142                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2143                                 printk(KERN_INFO
2144                                        "Written block @%llu (%s/%llu/?)"
2145                                        " !found in hash table, M.\n",
2146                                        bytenr, dev_state->name, dev_bytenr);
2147
2148                         ret = btrfsic_map_block(state, bytenr, processed_len,
2149                                                 &block_ctx, 0);
2150                         if (ret) {
2151                                 printk(KERN_INFO
2152                                        "btrfsic: btrfsic_map_block(root @%llu)"
2153                                        " failed!\n",
2154                                        dev_bytenr);
2155                                 goto continue_loop;
2156                         }
2157                 }
2158                 block_ctx.datav = mapped_datav;
2159                 /* the following is required in case of writes to mirrors,
2160                  * use the same that was used for the lookup */
2161                 block_ctx.dev = dev_state;
2162                 block_ctx.dev_bytenr = dev_bytenr;
2163
2164                 block = btrfsic_block_alloc();
2165                 if (NULL == block) {
2166                         printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2167                         btrfsic_release_block_ctx(&block_ctx);
2168                         goto continue_loop;
2169                 }
2170                 block->dev_state = dev_state;
2171                 block->dev_bytenr = dev_bytenr;
2172                 block->logical_bytenr = bytenr;
2173                 block->is_metadata = is_metadata;
2174                 block->never_written = 0;
2175                 block->iodone_w_error = 0;
2176                 block->mirror_num = 0;  /* unknown */
2177                 block->flush_gen = dev_state->last_flush_gen + 1;
2178                 block->submit_bio_bh_rw = submit_bio_bh_rw;
2179                 if (NULL != bio) {
2180                         block->is_iodone = 0;
2181                         BUG_ON(NULL == bio_is_patched);
2182                         if (!*bio_is_patched) {
2183                                 block->orig_bio_bh_private = bio->bi_private;
2184                                 block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2185                                 block->next_in_same_bio = NULL;
2186                                 bio->bi_private = block;
2187                                 bio->bi_end_io = btrfsic_bio_end_io;
2188                                 *bio_is_patched = 1;
2189                         } else {
2190                                 struct btrfsic_block *chained_block =
2191                                     (struct btrfsic_block *)
2192                                     bio->bi_private;
2193
2194                                 BUG_ON(NULL == chained_block);
2195                                 block->orig_bio_bh_private =
2196                                     chained_block->orig_bio_bh_private;
2197                                 block->orig_bio_bh_end_io.bio =
2198                                     chained_block->orig_bio_bh_end_io.bio;
2199                                 block->next_in_same_bio = chained_block;
2200                                 bio->bi_private = block;
2201                         }
2202                 } else if (NULL != bh) {
2203                         block->is_iodone = 0;
2204                         block->orig_bio_bh_private = bh->b_private;
2205                         block->orig_bio_bh_end_io.bh = bh->b_end_io;
2206                         block->next_in_same_bio = NULL;
2207                         bh->b_private = block;
2208                         bh->b_end_io = btrfsic_bh_end_io;
2209                 } else {
2210                         block->is_iodone = 1;
2211                         block->orig_bio_bh_private = NULL;
2212                         block->orig_bio_bh_end_io.bio = NULL;
2213                         block->next_in_same_bio = NULL;
2214                 }
2215                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2216                         printk(KERN_INFO
2217                                "New written %c-block @%llu (%s/%llu/%d)\n",
2218                                is_metadata ? 'M' : 'D',
2219                                block->logical_bytenr, block->dev_state->name,
2220                                block->dev_bytenr, block->mirror_num);
2221                 list_add(&block->all_blocks_node, &state->all_blocks_list);
2222                 btrfsic_block_hashtable_add(block, &state->block_hashtable);
2223
2224                 if (is_metadata) {
2225                         ret = btrfsic_process_metablock(state, block,
2226                                                         &block_ctx, 0, 0);
2227                         if (ret)
2228                                 printk(KERN_INFO
2229                                        "btrfsic: process_metablock(root @%llu)"
2230                                        " failed!\n",
2231                                        dev_bytenr);
2232                 }
2233                 btrfsic_release_block_ctx(&block_ctx);
2234         }
2235
2236 continue_loop:
2237         BUG_ON(!processed_len);
2238         dev_bytenr += processed_len;
2239         mapped_datav += processed_len >> PAGE_CACHE_SHIFT;
2240         num_pages -= processed_len >> PAGE_CACHE_SHIFT;
2241         goto again;
2242 }
2243
2244 static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status)
2245 {
2246         struct btrfsic_block *block = (struct btrfsic_block *)bp->bi_private;
2247         int iodone_w_error;
2248
2249         /* mutex is not held! This is not save if IO is not yet completed
2250          * on umount */
2251         iodone_w_error = 0;
2252         if (bio_error_status)
2253                 iodone_w_error = 1;
2254
2255         BUG_ON(NULL == block);
2256         bp->bi_private = block->orig_bio_bh_private;
2257         bp->bi_end_io = block->orig_bio_bh_end_io.bio;
2258
2259         do {
2260                 struct btrfsic_block *next_block;
2261                 struct btrfsic_dev_state *const dev_state = block->dev_state;
2262
2263                 if ((dev_state->state->print_mask &
2264                      BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2265                         printk(KERN_INFO
2266                                "bio_end_io(err=%d) for %c @%llu (%s/%llu/%d)\n",
2267                                bio_error_status,
2268                                btrfsic_get_block_type(dev_state->state, block),
2269                                block->logical_bytenr, dev_state->name,
2270                                block->dev_bytenr, block->mirror_num);
2271                 next_block = block->next_in_same_bio;
2272                 block->iodone_w_error = iodone_w_error;
2273                 if (block->submit_bio_bh_rw & REQ_FLUSH) {
2274                         dev_state->last_flush_gen++;
2275                         if ((dev_state->state->print_mask &
2276                              BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2277                                 printk(KERN_INFO
2278                                        "bio_end_io() new %s flush_gen=%llu\n",
2279                                        dev_state->name,
2280                                        dev_state->last_flush_gen);
2281                 }
2282                 if (block->submit_bio_bh_rw & REQ_FUA)
2283                         block->flush_gen = 0; /* FUA completed means block is
2284                                                * on disk */
2285                 block->is_iodone = 1; /* for FLUSH, this releases the block */
2286                 block = next_block;
2287         } while (NULL != block);
2288
2289         bp->bi_end_io(bp, bio_error_status);
2290 }
2291
2292 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate)
2293 {
2294         struct btrfsic_block *block = (struct btrfsic_block *)bh->b_private;
2295         int iodone_w_error = !uptodate;
2296         struct btrfsic_dev_state *dev_state;
2297
2298         BUG_ON(NULL == block);
2299         dev_state = block->dev_state;
2300         if ((dev_state->state->print_mask & BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2301                 printk(KERN_INFO
2302                        "bh_end_io(error=%d) for %c @%llu (%s/%llu/%d)\n",
2303                        iodone_w_error,
2304                        btrfsic_get_block_type(dev_state->state, block),
2305                        block->logical_bytenr, block->dev_state->name,
2306                        block->dev_bytenr, block->mirror_num);
2307
2308         block->iodone_w_error = iodone_w_error;
2309         if (block->submit_bio_bh_rw & REQ_FLUSH) {
2310                 dev_state->last_flush_gen++;
2311                 if ((dev_state->state->print_mask &
2312                      BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2313                         printk(KERN_INFO
2314                                "bh_end_io() new %s flush_gen=%llu\n",
2315                                dev_state->name, dev_state->last_flush_gen);
2316         }
2317         if (block->submit_bio_bh_rw & REQ_FUA)
2318                 block->flush_gen = 0; /* FUA completed means block is on disk */
2319
2320         bh->b_private = block->orig_bio_bh_private;
2321         bh->b_end_io = block->orig_bio_bh_end_io.bh;
2322         block->is_iodone = 1; /* for FLUSH, this releases the block */
2323         bh->b_end_io(bh, uptodate);
2324 }
2325
2326 static int btrfsic_process_written_superblock(
2327                 struct btrfsic_state *state,
2328                 struct btrfsic_block *const superblock,
2329                 struct btrfs_super_block *const super_hdr)
2330 {
2331         int pass;
2332
2333         superblock->generation = btrfs_super_generation(super_hdr);
2334         if (!(superblock->generation > state->max_superblock_generation ||
2335               0 == state->max_superblock_generation)) {
2336                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2337                         printk(KERN_INFO
2338                                "btrfsic: superblock @%llu (%s/%llu/%d)"
2339                                " with old gen %llu <= %llu\n",
2340                                superblock->logical_bytenr,
2341                                superblock->dev_state->name,
2342                                superblock->dev_bytenr, superblock->mirror_num,
2343                                btrfs_super_generation(super_hdr),
2344                                state->max_superblock_generation);
2345         } else {
2346                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2347                         printk(KERN_INFO
2348                                "btrfsic: got new superblock @%llu (%s/%llu/%d)"
2349                                " with new gen %llu > %llu\n",
2350                                superblock->logical_bytenr,
2351                                superblock->dev_state->name,
2352                                superblock->dev_bytenr, superblock->mirror_num,
2353                                btrfs_super_generation(super_hdr),
2354                                state->max_superblock_generation);
2355
2356                 state->max_superblock_generation =
2357                     btrfs_super_generation(super_hdr);
2358                 state->latest_superblock = superblock;
2359         }
2360
2361         for (pass = 0; pass < 3; pass++) {
2362                 int ret;
2363                 u64 next_bytenr;
2364                 struct btrfsic_block *next_block;
2365                 struct btrfsic_block_data_ctx tmp_next_block_ctx;
2366                 struct btrfsic_block_link *l;
2367                 int num_copies;
2368                 int mirror_num;
2369                 const char *additional_string = NULL;
2370                 struct btrfs_disk_key tmp_disk_key = {0};
2371
2372                 btrfs_set_disk_key_objectid(&tmp_disk_key,
2373                                             BTRFS_ROOT_ITEM_KEY);
2374                 btrfs_set_disk_key_objectid(&tmp_disk_key, 0);
2375
2376                 switch (pass) {
2377                 case 0:
2378                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2379                                                     BTRFS_ROOT_TREE_OBJECTID);
2380                         additional_string = "root ";
2381                         next_bytenr = btrfs_super_root(super_hdr);
2382                         if (state->print_mask &
2383                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2384                                 printk(KERN_INFO "root@%llu\n", next_bytenr);
2385                         break;
2386                 case 1:
2387                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2388                                                     BTRFS_CHUNK_TREE_OBJECTID);
2389                         additional_string = "chunk ";
2390                         next_bytenr = btrfs_super_chunk_root(super_hdr);
2391                         if (state->print_mask &
2392                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2393                                 printk(KERN_INFO "chunk@%llu\n", next_bytenr);
2394                         break;
2395                 case 2:
2396                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2397                                                     BTRFS_TREE_LOG_OBJECTID);
2398                         additional_string = "log ";
2399                         next_bytenr = btrfs_super_log_root(super_hdr);
2400                         if (0 == next_bytenr)
2401                                 continue;
2402                         if (state->print_mask &
2403                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2404                                 printk(KERN_INFO "log@%llu\n", next_bytenr);
2405                         break;
2406                 }
2407
2408                 num_copies =
2409                     btrfs_num_copies(state->root->fs_info,
2410                                      next_bytenr, BTRFS_SUPER_INFO_SIZE);
2411                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
2412                         printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
2413                                next_bytenr, num_copies);
2414                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2415                         int was_created;
2416
2417                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2418                                 printk(KERN_INFO
2419                                        "btrfsic_process_written_superblock("
2420                                        "mirror_num=%d)\n", mirror_num);
2421                         ret = btrfsic_map_block(state, next_bytenr,
2422                                                 BTRFS_SUPER_INFO_SIZE,
2423                                                 &tmp_next_block_ctx,
2424                                                 mirror_num);
2425                         if (ret) {
2426                                 printk(KERN_INFO
2427                                        "btrfsic: btrfsic_map_block(@%llu,"
2428                                        " mirror=%d) failed!\n",
2429                                        next_bytenr, mirror_num);
2430                                 return -1;
2431                         }
2432
2433                         next_block = btrfsic_block_lookup_or_add(
2434                                         state,
2435                                         &tmp_next_block_ctx,
2436                                         additional_string,
2437                                         1, 0, 1,
2438                                         mirror_num,
2439                                         &was_created);
2440                         if (NULL == next_block) {
2441                                 printk(KERN_INFO
2442                                        "btrfsic: error, kmalloc failed!\n");
2443                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
2444                                 return -1;
2445                         }
2446
2447                         next_block->disk_key = tmp_disk_key;
2448                         if (was_created)
2449                                 next_block->generation =
2450                                     BTRFSIC_GENERATION_UNKNOWN;
2451                         l = btrfsic_block_link_lookup_or_add(
2452                                         state,
2453                                         &tmp_next_block_ctx,
2454                                         next_block,
2455                                         superblock,
2456                                         BTRFSIC_GENERATION_UNKNOWN);
2457                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
2458                         if (NULL == l)
2459                                 return -1;
2460                 }
2461         }
2462
2463         if (WARN_ON(-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)))
2464                 btrfsic_dump_tree(state);
2465
2466         return 0;
2467 }
2468
2469 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
2470                                         struct btrfsic_block *const block,
2471                                         int recursion_level)
2472 {
2473         struct list_head *elem_ref_to;
2474         int ret = 0;
2475
2476         if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2477                 /*
2478                  * Note that this situation can happen and does not
2479                  * indicate an error in regular cases. It happens
2480                  * when disk blocks are freed and later reused.
2481                  * The check-integrity module is not aware of any
2482                  * block free operations, it just recognizes block
2483                  * write operations. Therefore it keeps the linkage
2484                  * information for a block until a block is
2485                  * rewritten. This can temporarily cause incorrect
2486                  * and even circular linkage informations. This
2487                  * causes no harm unless such blocks are referenced
2488                  * by the most recent super block.
2489                  */
2490                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2491                         printk(KERN_INFO
2492                                "btrfsic: abort cyclic linkage (case 1).\n");
2493
2494                 return ret;
2495         }
2496
2497         /*
2498          * This algorithm is recursive because the amount of used stack
2499          * space is very small and the max recursion depth is limited.
2500          */
2501         list_for_each(elem_ref_to, &block->ref_to_list) {
2502                 const struct btrfsic_block_link *const l =
2503                     list_entry(elem_ref_to, struct btrfsic_block_link,
2504                                node_ref_to);
2505
2506                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2507                         printk(KERN_INFO
2508                                "rl=%d, %c @%llu (%s/%llu/%d)"
2509                                " %u* refers to %c @%llu (%s/%llu/%d)\n",
2510                                recursion_level,
2511                                btrfsic_get_block_type(state, block),
2512                                block->logical_bytenr, block->dev_state->name,
2513                                block->dev_bytenr, block->mirror_num,
2514                                l->ref_cnt,
2515                                btrfsic_get_block_type(state, l->block_ref_to),
2516                                l->block_ref_to->logical_bytenr,
2517                                l->block_ref_to->dev_state->name,
2518                                l->block_ref_to->dev_bytenr,
2519                                l->block_ref_to->mirror_num);
2520                 if (l->block_ref_to->never_written) {
2521                         printk(KERN_INFO "btrfs: attempt to write superblock"
2522                                " which references block %c @%llu (%s/%llu/%d)"
2523                                " which is never written!\n",
2524                                btrfsic_get_block_type(state, l->block_ref_to),
2525                                l->block_ref_to->logical_bytenr,
2526                                l->block_ref_to->dev_state->name,
2527                                l->block_ref_to->dev_bytenr,
2528                                l->block_ref_to->mirror_num);
2529                         ret = -1;
2530                 } else if (!l->block_ref_to->is_iodone) {
2531                         printk(KERN_INFO "btrfs: attempt to write superblock"
2532                                " which references block %c @%llu (%s/%llu/%d)"
2533                                " which is not yet iodone!\n",
2534                                btrfsic_get_block_type(state, l->block_ref_to),
2535                                l->block_ref_to->logical_bytenr,
2536                                l->block_ref_to->dev_state->name,
2537                                l->block_ref_to->dev_bytenr,
2538                                l->block_ref_to->mirror_num);
2539                         ret = -1;
2540                 } else if (l->block_ref_to->iodone_w_error) {
2541                         printk(KERN_INFO "btrfs: attempt to write superblock"
2542                                " which references block %c @%llu (%s/%llu/%d)"
2543                                " which has write error!\n",
2544                                btrfsic_get_block_type(state, l->block_ref_to),
2545                                l->block_ref_to->logical_bytenr,
2546                                l->block_ref_to->dev_state->name,
2547                                l->block_ref_to->dev_bytenr,
2548                                l->block_ref_to->mirror_num);
2549                         ret = -1;
2550                 } else if (l->parent_generation !=
2551                            l->block_ref_to->generation &&
2552                            BTRFSIC_GENERATION_UNKNOWN !=
2553                            l->parent_generation &&
2554                            BTRFSIC_GENERATION_UNKNOWN !=
2555                            l->block_ref_to->generation) {
2556                         printk(KERN_INFO "btrfs: attempt to write superblock"
2557                                " which references block %c @%llu (%s/%llu/%d)"
2558                                " with generation %llu !="
2559                                " parent generation %llu!\n",
2560                                btrfsic_get_block_type(state, l->block_ref_to),
2561                                l->block_ref_to->logical_bytenr,
2562                                l->block_ref_to->dev_state->name,
2563                                l->block_ref_to->dev_bytenr,
2564                                l->block_ref_to->mirror_num,
2565                                l->block_ref_to->generation,
2566                                l->parent_generation);
2567                         ret = -1;
2568                 } else if (l->block_ref_to->flush_gen >
2569                            l->block_ref_to->dev_state->last_flush_gen) {
2570                         printk(KERN_INFO "btrfs: attempt to write superblock"
2571                                " which references block %c @%llu (%s/%llu/%d)"
2572                                " which is not flushed out of disk's write cache"
2573                                " (block flush_gen=%llu,"
2574                                " dev->flush_gen=%llu)!\n",
2575                                btrfsic_get_block_type(state, l->block_ref_to),
2576                                l->block_ref_to->logical_bytenr,
2577                                l->block_ref_to->dev_state->name,
2578                                l->block_ref_to->dev_bytenr,
2579                                l->block_ref_to->mirror_num, block->flush_gen,
2580                                l->block_ref_to->dev_state->last_flush_gen);
2581                         ret = -1;
2582                 } else if (-1 == btrfsic_check_all_ref_blocks(state,
2583                                                               l->block_ref_to,
2584                                                               recursion_level +
2585                                                               1)) {
2586                         ret = -1;
2587                 }
2588         }
2589
2590         return ret;
2591 }
2592
2593 static int btrfsic_is_block_ref_by_superblock(
2594                 const struct btrfsic_state *state,
2595                 const struct btrfsic_block *block,
2596                 int recursion_level)
2597 {
2598         struct list_head *elem_ref_from;
2599
2600         if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2601                 /* refer to comment at "abort cyclic linkage (case 1)" */
2602                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2603                         printk(KERN_INFO
2604                                "btrfsic: abort cyclic linkage (case 2).\n");
2605
2606                 return 0;
2607         }
2608
2609         /*
2610          * This algorithm is recursive because the amount of used stack space
2611          * is very small and the max recursion depth is limited.
2612          */
2613         list_for_each(elem_ref_from, &block->ref_from_list) {
2614                 const struct btrfsic_block_link *const l =
2615                     list_entry(elem_ref_from, struct btrfsic_block_link,
2616                                node_ref_from);
2617
2618                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2619                         printk(KERN_INFO
2620                                "rl=%d, %c @%llu (%s/%llu/%d)"
2621                                " is ref %u* from %c @%llu (%s/%llu/%d)\n",
2622                                recursion_level,
2623                                btrfsic_get_block_type(state, block),
2624                                block->logical_bytenr, block->dev_state->name,
2625                                block->dev_bytenr, block->mirror_num,
2626                                l->ref_cnt,
2627                                btrfsic_get_block_type(state, l->block_ref_from),
2628                                l->block_ref_from->logical_bytenr,
2629                                l->block_ref_from->dev_state->name,
2630                                l->block_ref_from->dev_bytenr,
2631                                l->block_ref_from->mirror_num);
2632                 if (l->block_ref_from->is_superblock &&
2633                     state->latest_superblock->dev_bytenr ==
2634                     l->block_ref_from->dev_bytenr &&
2635                     state->latest_superblock->dev_state->bdev ==
2636                     l->block_ref_from->dev_state->bdev)
2637                         return 1;
2638                 else if (btrfsic_is_block_ref_by_superblock(state,
2639                                                             l->block_ref_from,
2640                                                             recursion_level +
2641                                                             1))
2642                         return 1;
2643         }
2644
2645         return 0;
2646 }
2647
2648 static void btrfsic_print_add_link(const struct btrfsic_state *state,
2649                                    const struct btrfsic_block_link *l)
2650 {
2651         printk(KERN_INFO
2652                "Add %u* link from %c @%llu (%s/%llu/%d)"
2653                " to %c @%llu (%s/%llu/%d).\n",
2654                l->ref_cnt,
2655                btrfsic_get_block_type(state, l->block_ref_from),
2656                l->block_ref_from->logical_bytenr,
2657                l->block_ref_from->dev_state->name,
2658                l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2659                btrfsic_get_block_type(state, l->block_ref_to),
2660                l->block_ref_to->logical_bytenr,
2661                l->block_ref_to->dev_state->name, l->block_ref_to->dev_bytenr,
2662                l->block_ref_to->mirror_num);
2663 }
2664
2665 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
2666                                    const struct btrfsic_block_link *l)
2667 {
2668         printk(KERN_INFO
2669                "Rem %u* link from %c @%llu (%s/%llu/%d)"
2670                " to %c @%llu (%s/%llu/%d).\n",
2671                l->ref_cnt,
2672                btrfsic_get_block_type(state, l->block_ref_from),
2673                l->block_ref_from->logical_bytenr,
2674                l->block_ref_from->dev_state->name,
2675                l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2676                btrfsic_get_block_type(state, l->block_ref_to),
2677                l->block_ref_to->logical_bytenr,
2678                l->block_ref_to->dev_state->name, l->block_ref_to->dev_bytenr,
2679                l->block_ref_to->mirror_num);
2680 }
2681
2682 static char btrfsic_get_block_type(const struct btrfsic_state *state,
2683                                    const struct btrfsic_block *block)
2684 {
2685         if (block->is_superblock &&
2686             state->latest_superblock->dev_bytenr == block->dev_bytenr &&
2687             state->latest_superblock->dev_state->bdev == block->dev_state->bdev)
2688                 return 'S';
2689         else if (block->is_superblock)
2690                 return 's';
2691         else if (block->is_metadata)
2692                 return 'M';
2693         else
2694                 return 'D';
2695 }
2696
2697 static void btrfsic_dump_tree(const struct btrfsic_state *state)
2698 {
2699         btrfsic_dump_tree_sub(state, state->latest_superblock, 0);
2700 }
2701
2702 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
2703                                   const struct btrfsic_block *block,
2704                                   int indent_level)
2705 {
2706         struct list_head *elem_ref_to;
2707         int indent_add;
2708         static char buf[80];
2709         int cursor_position;
2710
2711         /*
2712          * Should better fill an on-stack buffer with a complete line and
2713          * dump it at once when it is time to print a newline character.
2714          */
2715
2716         /*
2717          * This algorithm is recursive because the amount of used stack space
2718          * is very small and the max recursion depth is limited.
2719          */
2720         indent_add = sprintf(buf, "%c-%llu(%s/%llu/%d)",
2721                              btrfsic_get_block_type(state, block),
2722                              block->logical_bytenr, block->dev_state->name,
2723                              block->dev_bytenr, block->mirror_num);
2724         if (indent_level + indent_add > BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2725                 printk("[...]\n");
2726                 return;
2727         }
2728         printk(buf);
2729         indent_level += indent_add;
2730         if (list_empty(&block->ref_to_list)) {
2731                 printk("\n");
2732                 return;
2733         }
2734         if (block->mirror_num > 1 &&
2735             !(state->print_mask & BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS)) {
2736                 printk(" [...]\n");
2737                 return;
2738         }
2739
2740         cursor_position = indent_level;
2741         list_for_each(elem_ref_to, &block->ref_to_list) {
2742                 const struct btrfsic_block_link *const l =
2743                     list_entry(elem_ref_to, struct btrfsic_block_link,
2744                                node_ref_to);
2745
2746                 while (cursor_position < indent_level) {
2747                         printk(" ");
2748                         cursor_position++;
2749                 }
2750                 if (l->ref_cnt > 1)
2751                         indent_add = sprintf(buf, " %d*--> ", l->ref_cnt);
2752                 else
2753                         indent_add = sprintf(buf, " --> ");
2754                 if (indent_level + indent_add >
2755                     BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2756                         printk("[...]\n");
2757                         cursor_position = 0;
2758                         continue;
2759                 }
2760
2761                 printk(buf);
2762
2763                 btrfsic_dump_tree_sub(state, l->block_ref_to,
2764                                       indent_level + indent_add);
2765                 cursor_position = 0;
2766         }
2767 }
2768
2769 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
2770                 struct btrfsic_state *state,
2771                 struct btrfsic_block_data_ctx *next_block_ctx,
2772                 struct btrfsic_block *next_block,
2773                 struct btrfsic_block *from_block,
2774                 u64 parent_generation)
2775 {
2776         struct btrfsic_block_link *l;
2777
2778         l = btrfsic_block_link_hashtable_lookup(next_block_ctx->dev->bdev,
2779                                                 next_block_ctx->dev_bytenr,
2780                                                 from_block->dev_state->bdev,
2781                                                 from_block->dev_bytenr,
2782                                                 &state->block_link_hashtable);
2783         if (NULL == l) {
2784                 l = btrfsic_block_link_alloc();
2785                 if (NULL == l) {
2786                         printk(KERN_INFO
2787                                "btrfsic: error, kmalloc" " failed!\n");
2788                         return NULL;
2789                 }
2790
2791                 l->block_ref_to = next_block;
2792                 l->block_ref_from = from_block;
2793                 l->ref_cnt = 1;
2794                 l->parent_generation = parent_generation;
2795
2796                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2797                         btrfsic_print_add_link(state, l);
2798
2799                 list_add(&l->node_ref_to, &from_block->ref_to_list);
2800                 list_add(&l->node_ref_from, &next_block->ref_from_list);
2801
2802                 btrfsic_block_link_hashtable_add(l,
2803                                                  &state->block_link_hashtable);
2804         } else {
2805                 l->ref_cnt++;
2806                 l->parent_generation = parent_generation;
2807                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2808                         btrfsic_print_add_link(state, l);
2809         }
2810
2811         return l;
2812 }
2813
2814 static struct btrfsic_block *btrfsic_block_lookup_or_add(
2815                 struct btrfsic_state *state,
2816                 struct btrfsic_block_data_ctx *block_ctx,
2817                 const char *additional_string,
2818                 int is_metadata,
2819                 int is_iodone,
2820                 int never_written,
2821                 int mirror_num,
2822                 int *was_created)
2823 {
2824         struct btrfsic_block *block;
2825
2826         block = btrfsic_block_hashtable_lookup(block_ctx->dev->bdev,
2827                                                block_ctx->dev_bytenr,
2828                                                &state->block_hashtable);
2829         if (NULL == block) {
2830                 struct btrfsic_dev_state *dev_state;
2831
2832                 block = btrfsic_block_alloc();
2833                 if (NULL == block) {
2834                         printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2835                         return NULL;
2836                 }
2837                 dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev);
2838                 if (NULL == dev_state) {
2839                         printk(KERN_INFO
2840                                "btrfsic: error, lookup dev_state failed!\n");
2841                         btrfsic_block_free(block);
2842                         return NULL;
2843                 }
2844                 block->dev_state = dev_state;
2845                 block->dev_bytenr = block_ctx->dev_bytenr;
2846                 block->logical_bytenr = block_ctx->start;
2847                 block->is_metadata = is_metadata;
2848                 block->is_iodone = is_iodone;
2849                 block->never_written = never_written;
2850                 block->mirror_num = mirror_num;
2851                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2852                         printk(KERN_INFO
2853                                "New %s%c-block @%llu (%s/%llu/%d)\n",
2854                                additional_string,
2855                                btrfsic_get_block_type(state, block),
2856                                block->logical_bytenr, dev_state->name,
2857                                block->dev_bytenr, mirror_num);
2858                 list_add(&block->all_blocks_node, &state->all_blocks_list);
2859                 btrfsic_block_hashtable_add(block, &state->block_hashtable);
2860                 if (NULL != was_created)
2861                         *was_created = 1;
2862         } else {
2863                 if (NULL != was_created)
2864                         *was_created = 0;
2865         }
2866
2867         return block;
2868 }
2869
2870 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
2871                                            u64 bytenr,
2872                                            struct btrfsic_dev_state *dev_state,
2873                                            u64 dev_bytenr)
2874 {
2875         int num_copies;
2876         int mirror_num;
2877         int ret;
2878         struct btrfsic_block_data_ctx block_ctx;
2879         int match = 0;
2880
2881         num_copies = btrfs_num_copies(state->root->fs_info,
2882                                       bytenr, state->metablock_size);
2883
2884         for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2885                 ret = btrfsic_map_block(state, bytenr, state->metablock_size,
2886                                         &block_ctx, mirror_num);
2887                 if (ret) {
2888                         printk(KERN_INFO "btrfsic:"
2889                                " btrfsic_map_block(logical @%llu,"
2890                                " mirror %d) failed!\n",
2891                                bytenr, mirror_num);
2892                         continue;
2893                 }
2894
2895                 if (dev_state->bdev == block_ctx.dev->bdev &&
2896                     dev_bytenr == block_ctx.dev_bytenr) {
2897                         match++;
2898                         btrfsic_release_block_ctx(&block_ctx);
2899                         break;
2900                 }
2901                 btrfsic_release_block_ctx(&block_ctx);
2902         }
2903
2904         if (WARN_ON(!match)) {
2905                 printk(KERN_INFO "btrfs: attempt to write M-block which contains logical bytenr that doesn't map to dev+physical bytenr of submit_bio,"
2906                        " buffer->log_bytenr=%llu, submit_bio(bdev=%s,"
2907                        " phys_bytenr=%llu)!\n",
2908                        bytenr, dev_state->name, dev_bytenr);
2909                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2910                         ret = btrfsic_map_block(state, bytenr,
2911                                                 state->metablock_size,
2912                                                 &block_ctx, mirror_num);
2913                         if (ret)
2914                                 continue;
2915
2916                         printk(KERN_INFO "Read logical bytenr @%llu maps to"
2917                                " (%s/%llu/%d)\n",
2918                                bytenr, block_ctx.dev->name,
2919                                block_ctx.dev_bytenr, mirror_num);
2920                 }
2921         }
2922 }
2923
2924 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
2925                 struct block_device *bdev)
2926 {
2927         struct btrfsic_dev_state *ds;
2928
2929         ds = btrfsic_dev_state_hashtable_lookup(bdev,
2930                                                 &btrfsic_dev_state_hashtable);
2931         return ds;
2932 }
2933
2934 int btrfsic_submit_bh(int rw, struct buffer_head *bh)
2935 {
2936         struct btrfsic_dev_state *dev_state;
2937
2938         if (!btrfsic_is_initialized)
2939                 return submit_bh(rw, bh);
2940
2941         mutex_lock(&btrfsic_mutex);
2942         /* since btrfsic_submit_bh() might also be called before
2943          * btrfsic_mount(), this might return NULL */
2944         dev_state = btrfsic_dev_state_lookup(bh->b_bdev);
2945
2946         /* Only called to write the superblock (incl. FLUSH/FUA) */
2947         if (NULL != dev_state &&
2948             (rw & WRITE) && bh->b_size > 0) {
2949                 u64 dev_bytenr;
2950
2951                 dev_bytenr = 4096 * bh->b_blocknr;
2952                 if (dev_state->state->print_mask &
2953                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2954                         printk(KERN_INFO
2955                                "submit_bh(rw=0x%x, blocknr=%llu (bytenr %llu),"
2956                                " size=%zu, data=%p, bdev=%p)\n",
2957                                rw, (unsigned long long)bh->b_blocknr,
2958                                dev_bytenr, bh->b_size, bh->b_data, bh->b_bdev);
2959                 btrfsic_process_written_block(dev_state, dev_bytenr,
2960                                               &bh->b_data, 1, NULL,
2961                                               NULL, bh, rw);
2962         } else if (NULL != dev_state && (rw & REQ_FLUSH)) {
2963                 if (dev_state->state->print_mask &
2964                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2965                         printk(KERN_INFO
2966                                "submit_bh(rw=0x%x FLUSH, bdev=%p)\n",
2967                                rw, bh->b_bdev);
2968                 if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
2969                         if ((dev_state->state->print_mask &
2970                              (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2971                               BTRFSIC_PRINT_MASK_VERBOSE)))
2972                                 printk(KERN_INFO
2973                                        "btrfsic_submit_bh(%s) with FLUSH"
2974                                        " but dummy block already in use"
2975                                        " (ignored)!\n",
2976                                        dev_state->name);
2977                 } else {
2978                         struct btrfsic_block *const block =
2979                                 &dev_state->dummy_block_for_bio_bh_flush;
2980
2981                         block->is_iodone = 0;
2982                         block->never_written = 0;
2983                         block->iodone_w_error = 0;
2984                         block->flush_gen = dev_state->last_flush_gen + 1;
2985                         block->submit_bio_bh_rw = rw;
2986                         block->orig_bio_bh_private = bh->b_private;
2987                         block->orig_bio_bh_end_io.bh = bh->b_end_io;
2988                         block->next_in_same_bio = NULL;
2989                         bh->b_private = block;
2990                         bh->b_end_io = btrfsic_bh_end_io;
2991                 }
2992         }
2993         mutex_unlock(&btrfsic_mutex);
2994         return submit_bh(rw, bh);
2995 }
2996
2997 static void __btrfsic_submit_bio(int rw, struct bio *bio)
2998 {
2999         struct btrfsic_dev_state *dev_state;
3000
3001         if (!btrfsic_is_initialized)
3002                 return;
3003
3004         mutex_lock(&btrfsic_mutex);
3005         /* since btrfsic_submit_bio() is also called before
3006          * btrfsic_mount(), this might return NULL */
3007         dev_state = btrfsic_dev_state_lookup(bio->bi_bdev);
3008         if (NULL != dev_state &&
3009             (rw & WRITE) && NULL != bio->bi_io_vec) {
3010                 unsigned int i;
3011                 u64 dev_bytenr;
3012                 u64 cur_bytenr;
3013                 int bio_is_patched;
3014                 char **mapped_datav;
3015
3016                 dev_bytenr = 512 * bio->bi_sector;
3017                 bio_is_patched = 0;
3018                 if (dev_state->state->print_mask &
3019                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3020                         printk(KERN_INFO
3021                                "submit_bio(rw=0x%x, bi_vcnt=%u,"
3022                                " bi_sector=%llu (bytenr %llu), bi_bdev=%p)\n",
3023                                rw, bio->bi_vcnt,
3024                                (unsigned long long)bio->bi_sector, dev_bytenr,
3025                                bio->bi_bdev);
3026
3027                 mapped_datav = kmalloc(sizeof(*mapped_datav) * bio->bi_vcnt,
3028                                        GFP_NOFS);
3029                 if (!mapped_datav)
3030                         goto leave;
3031                 cur_bytenr = dev_bytenr;
3032                 for (i = 0; i < bio->bi_vcnt; i++) {
3033                         BUG_ON(bio->bi_io_vec[i].bv_len != PAGE_CACHE_SIZE);
3034                         mapped_datav[i] = kmap(bio->bi_io_vec[i].bv_page);
3035                         if (!mapped_datav[i]) {
3036                                 while (i > 0) {
3037                                         i--;
3038                                         kunmap(bio->bi_io_vec[i].bv_page);
3039                                 }
3040                                 kfree(mapped_datav);
3041                                 goto leave;
3042                         }
3043                         if (dev_state->state->print_mask &
3044                             BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE)
3045                                 printk(KERN_INFO
3046                                        "#%u: bytenr=%llu, len=%u, offset=%u\n",
3047                                        i, cur_bytenr, bio->bi_io_vec[i].bv_len,
3048                                        bio->bi_io_vec[i].bv_offset);
3049                         cur_bytenr += bio->bi_io_vec[i].bv_len;
3050                 }
3051                 btrfsic_process_written_block(dev_state, dev_bytenr,
3052                                               mapped_datav, bio->bi_vcnt,
3053                                               bio, &bio_is_patched,
3054                                               NULL, rw);
3055                 while (i > 0) {
3056                         i--;
3057                         kunmap(bio->bi_io_vec[i].bv_page);
3058                 }
3059                 kfree(mapped_datav);
3060         } else if (NULL != dev_state && (rw & REQ_FLUSH)) {
3061                 if (dev_state->state->print_mask &
3062                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3063                         printk(KERN_INFO
3064                                "submit_bio(rw=0x%x FLUSH, bdev=%p)\n",
3065                                rw, bio->bi_bdev);
3066                 if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
3067                         if ((dev_state->state->print_mask &
3068                              (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3069                               BTRFSIC_PRINT_MASK_VERBOSE)))
3070                                 printk(KERN_INFO
3071                                        "btrfsic_submit_bio(%s) with FLUSH"
3072                                        " but dummy block already in use"
3073                                        " (ignored)!\n",
3074                                        dev_state->name);
3075                 } else {
3076                         struct btrfsic_block *const block =
3077                                 &dev_state->dummy_block_for_bio_bh_flush;
3078
3079                         block->is_iodone = 0;
3080                         block->never_written = 0;
3081                         block->iodone_w_error = 0;
3082                         block->flush_gen = dev_state->last_flush_gen + 1;
3083                         block->submit_bio_bh_rw = rw;
3084                         block->orig_bio_bh_private = bio->bi_private;
3085                         block->orig_bio_bh_end_io.bio = bio->bi_end_io;
3086                         block->next_in_same_bio = NULL;
3087                         bio->bi_private = block;
3088                         bio->bi_end_io = btrfsic_bio_end_io;
3089                 }
3090         }
3091 leave:
3092         mutex_unlock(&btrfsic_mutex);
3093 }
3094
3095 void btrfsic_submit_bio(int rw, struct bio *bio)
3096 {
3097         __btrfsic_submit_bio(rw, bio);
3098         submit_bio(rw, bio);
3099 }
3100
3101 int btrfsic_submit_bio_wait(int rw, struct bio *bio)
3102 {
3103         __btrfsic_submit_bio(rw, bio);
3104         return submit_bio_wait(rw, bio);
3105 }
3106
3107 int btrfsic_mount(struct btrfs_root *root,
3108                   struct btrfs_fs_devices *fs_devices,
3109                   int including_extent_data, u32 print_mask)
3110 {
3111         int ret;
3112         struct btrfsic_state *state;
3113         struct list_head *dev_head = &fs_devices->devices;
3114         struct btrfs_device *device;
3115
3116         if (root->nodesize != root->leafsize) {
3117                 printk(KERN_INFO
3118                        "btrfsic: cannot handle nodesize %d != leafsize %d!\n",
3119                        root->nodesize, root->leafsize);
3120                 return -1;
3121         }
3122         if (root->nodesize & ((u64)PAGE_CACHE_SIZE - 1)) {
3123                 printk(KERN_INFO
3124                        "btrfsic: cannot handle nodesize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3125                        root->nodesize, PAGE_CACHE_SIZE);
3126                 return -1;
3127         }
3128         if (root->leafsize & ((u64)PAGE_CACHE_SIZE - 1)) {
3129                 printk(KERN_INFO
3130                        "btrfsic: cannot handle leafsize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3131                        root->leafsize, PAGE_CACHE_SIZE);
3132                 return -1;
3133         }
3134         if (root->sectorsize & ((u64)PAGE_CACHE_SIZE - 1)) {
3135                 printk(KERN_INFO
3136                        "btrfsic: cannot handle sectorsize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3137                        root->sectorsize, PAGE_CACHE_SIZE);
3138                 return -1;
3139         }
3140         state = kzalloc(sizeof(*state), GFP_NOFS);
3141         if (NULL == state) {
3142                 printk(KERN_INFO "btrfs check-integrity: kmalloc() failed!\n");
3143                 return -1;
3144         }
3145
3146         if (!btrfsic_is_initialized) {
3147                 mutex_init(&btrfsic_mutex);
3148                 btrfsic_dev_state_hashtable_init(&btrfsic_dev_state_hashtable);
3149                 btrfsic_is_initialized = 1;
3150         }
3151         mutex_lock(&btrfsic_mutex);
3152         state->root = root;
3153         state->print_mask = print_mask;
3154         state->include_extent_data = including_extent_data;
3155         state->csum_size = 0;
3156         state->metablock_size = root->nodesize;
3157         state->datablock_size = root->sectorsize;
3158         INIT_LIST_HEAD(&state->all_blocks_list);
3159         btrfsic_block_hashtable_init(&state->block_hashtable);
3160         btrfsic_block_link_hashtable_init(&state->block_link_hashtable);
3161         state->max_superblock_generation = 0;
3162         state->latest_superblock = NULL;
3163
3164         list_for_each_entry(device, dev_head, dev_list) {
3165                 struct btrfsic_dev_state *ds;
3166                 char *p;
3167
3168                 if (!device->bdev || !device->name)
3169                         continue;
3170
3171                 ds = btrfsic_dev_state_alloc();
3172                 if (NULL == ds) {
3173                         printk(KERN_INFO
3174                                "btrfs check-integrity: kmalloc() failed!\n");
3175                         mutex_unlock(&btrfsic_mutex);
3176                         return -1;
3177                 }
3178                 ds->bdev = device->bdev;
3179                 ds->state = state;
3180                 bdevname(ds->bdev, ds->name);
3181                 ds->name[BDEVNAME_SIZE - 1] = '\0';
3182                 for (p = ds->name; *p != '\0'; p++);
3183                 while (p > ds->name && *p != '/')
3184                         p--;
3185                 if (*p == '/')
3186                         p++;
3187                 strlcpy(ds->name, p, sizeof(ds->name));
3188                 btrfsic_dev_state_hashtable_add(ds,
3189                                                 &btrfsic_dev_state_hashtable);
3190         }
3191
3192         ret = btrfsic_process_superblock(state, fs_devices);
3193         if (0 != ret) {
3194                 mutex_unlock(&btrfsic_mutex);
3195                 btrfsic_unmount(root, fs_devices);
3196                 return ret;
3197         }
3198
3199         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_DATABASE)
3200                 btrfsic_dump_database(state);
3201         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_TREE)
3202                 btrfsic_dump_tree(state);
3203
3204         mutex_unlock(&btrfsic_mutex);
3205         return 0;
3206 }
3207
3208 void btrfsic_unmount(struct btrfs_root *root,
3209                      struct btrfs_fs_devices *fs_devices)
3210 {
3211         struct list_head *elem_all;
3212         struct list_head *tmp_all;
3213         struct btrfsic_state *state;
3214         struct list_head *dev_head = &fs_devices->devices;
3215         struct btrfs_device *device;
3216
3217         if (!btrfsic_is_initialized)
3218                 return;
3219
3220         mutex_lock(&btrfsic_mutex);
3221
3222         state = NULL;
3223         list_for_each_entry(device, dev_head, dev_list) {
3224                 struct btrfsic_dev_state *ds;
3225
3226                 if (!device->bdev || !device->name)
3227                         continue;
3228
3229                 ds = btrfsic_dev_state_hashtable_lookup(
3230                                 device->bdev,
3231                                 &btrfsic_dev_state_hashtable);
3232                 if (NULL != ds) {
3233                         state = ds->state;
3234                         btrfsic_dev_state_hashtable_remove(ds);
3235                         btrfsic_dev_state_free(ds);
3236                 }
3237         }
3238
3239         if (NULL == state) {
3240                 printk(KERN_INFO
3241                        "btrfsic: error, cannot find state information"
3242                        " on umount!\n");
3243                 mutex_unlock(&btrfsic_mutex);
3244                 return;
3245         }
3246
3247         /*
3248          * Don't care about keeping the lists' state up to date,
3249          * just free all memory that was allocated dynamically.
3250          * Free the blocks and the block_links.
3251          */
3252         list_for_each_safe(elem_all, tmp_all, &state->all_blocks_list) {
3253                 struct btrfsic_block *const b_all =
3254                     list_entry(elem_all, struct btrfsic_block,
3255                                all_blocks_node);
3256                 struct list_head *elem_ref_to;
3257                 struct list_head *tmp_ref_to;
3258
3259                 list_for_each_safe(elem_ref_to, tmp_ref_to,
3260                                    &b_all->ref_to_list) {
3261                         struct btrfsic_block_link *const l =
3262                             list_entry(elem_ref_to,
3263                                        struct btrfsic_block_link,
3264                                        node_ref_to);
3265
3266                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
3267                                 btrfsic_print_rem_link(state, l);
3268
3269                         l->ref_cnt--;
3270                         if (0 == l->ref_cnt)
3271                                 btrfsic_block_link_free(l);
3272                 }
3273
3274                 if (b_all->is_iodone || b_all->never_written)
3275                         btrfsic_block_free(b_all);
3276                 else
3277                         printk(KERN_INFO "btrfs: attempt to free %c-block"
3278                                " @%llu (%s/%llu/%d) on umount which is"
3279                                " not yet iodone!\n",
3280                                btrfsic_get_block_type(state, b_all),
3281                                b_all->logical_bytenr, b_all->dev_state->name,
3282                                b_all->dev_bytenr, b_all->mirror_num);
3283         }
3284
3285         mutex_unlock(&btrfsic_mutex);
3286
3287         kfree(state);
3288 }