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