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",
 705                                        (unsigned long long)next_bytenr);
 706                         break;
 707                 case 1:
 708                         next_bytenr = btrfs_super_chunk_root(selected_super);
 709                         if (state->print_mask &
 710                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 711                                 printk(KERN_INFO "chunk@%llu\n",
 712                                        (unsigned long long)next_bytenr);
 713                         break;
 714                 case 2:
 715                         next_bytenr = btrfs_super_log_root(selected_super);
 716                         if (0 == next_bytenr)
 717                                 continue;
 718                         if (state->print_mask &
 719                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 720                                 printk(KERN_INFO "log@%llu\n",
 721                                        (unsigned long long)next_bytenr);
 722                         break;
 723                 }
 724
 725                 num_copies =
 726                     btrfs_num_copies(state->root->fs_info,
 727                                      next_bytenr, state->metablock_size);
 728                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 729                         printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
 730                                (unsigned long long)next_bytenr, num_copies);
 731
 732                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 733                         struct btrfsic_block *next_block;
 734                         struct btrfsic_block_data_ctx tmp_next_block_ctx;
 735                         struct btrfsic_block_link *l;
 736
 737                         ret = btrfsic_map_block(state, next_bytenr,
 738                                                 state->metablock_size,
 739                                                 &tmp_next_block_ctx,
 740                                                 mirror_num);
 741                         if (ret) {
 742                                 printk(KERN_INFO "btrfsic:"
 743                                        " btrfsic_map_block(root @%llu,"
 744                                        " mirror %d) failed!\n",
 745                                        (unsigned long long)next_bytenr,
 746                                        mirror_num);
 747                                 kfree(selected_super);
 748                                 return -1;
 749                         }
 750
 751                         next_block = btrfsic_block_hashtable_lookup(
 752                                         tmp_next_block_ctx.dev->bdev,
 753                                         tmp_next_block_ctx.dev_bytenr,
 754                                         &state->block_hashtable);
 755                         BUG_ON(NULL == next_block);
 756
 757                         l = btrfsic_block_link_hashtable_lookup(
 758                                         tmp_next_block_ctx.dev->bdev,
 759                                         tmp_next_block_ctx.dev_bytenr,
 760                                         state->latest_superblock->dev_state->
 761                                         bdev,
 762                                         state->latest_superblock->dev_bytenr,
 763                                         &state->block_link_hashtable);
 764                         BUG_ON(NULL == l);
 765
 766                         ret = btrfsic_read_block(state, &tmp_next_block_ctx);
 767                         if (ret < (int)PAGE_CACHE_SIZE) {
 768                                 printk(KERN_INFO
 769                                        "btrfsic: read @logical %llu failed!\n",
 770                                        (unsigned long long)
 771                                        tmp_next_block_ctx.start);
 772                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
 773                                 kfree(selected_super);
 774                                 return -1;
 775                         }
 776
 777                         ret = btrfsic_process_metablock(state,
 778                                                         next_block,
 779                                                         &tmp_next_block_ctx,
 780                                                         BTRFS_MAX_LEVEL + 3, 1);
 781                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
 782                 }
 783         }
 784
 785         kfree(selected_super);
 786         return ret;
 787 }
 788
 789 static int btrfsic_process_superblock_dev_mirror(
 790                 struct btrfsic_state *state,
 791                 struct btrfsic_dev_state *dev_state,
 792                 struct btrfs_device *device,
 793                 int superblock_mirror_num,
 794                 struct btrfsic_dev_state **selected_dev_state,
 795                 struct btrfs_super_block *selected_super)
 796 {
 797         struct btrfs_super_block *super_tmp;
 798         u64 dev_bytenr;
 799         struct buffer_head *bh;
 800         struct btrfsic_block *superblock_tmp;
 801         int pass;
 802         struct block_device *const superblock_bdev = device->bdev;
 803
 804         /* super block bytenr is always the unmapped device bytenr */
 805         dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
 806         if (dev_bytenr + BTRFS_SUPER_INFO_SIZE > device->total_bytes)
 807                 return -1;
 808         bh = __bread(superblock_bdev, dev_bytenr / 4096,
 809                      BTRFS_SUPER_INFO_SIZE);
 810         if (NULL == bh)
 811                 return -1;
 812         super_tmp = (struct btrfs_super_block *)
 813             (bh->b_data + (dev_bytenr & 4095));
 814
 815         if (btrfs_super_bytenr(super_tmp) != dev_bytenr ||
 816             strncmp((char *)(&(super_tmp->magic)), BTRFS_MAGIC,
 817                     sizeof(super_tmp->magic)) ||
 818             memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE) ||
 819             btrfs_super_nodesize(super_tmp) != state->metablock_size ||
 820             btrfs_super_leafsize(super_tmp) != state->metablock_size ||
 821             btrfs_super_sectorsize(super_tmp) != state->datablock_size) {
 822                 brelse(bh);
 823                 return 0;
 824         }
 825
 826         superblock_tmp =
 827             btrfsic_block_hashtable_lookup(superblock_bdev,
 828                                            dev_bytenr,
 829                                            &state->block_hashtable);
 830         if (NULL == superblock_tmp) {
 831                 superblock_tmp = btrfsic_block_alloc();
 832                 if (NULL == superblock_tmp) {
 833                         printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
 834                         brelse(bh);
 835                         return -1;
 836                 }
 837                 /* for superblock, only the dev_bytenr makes sense */
 838                 superblock_tmp->dev_bytenr = dev_bytenr;
 839                 superblock_tmp->dev_state = dev_state;
 840                 superblock_tmp->logical_bytenr = dev_bytenr;
 841                 superblock_tmp->generation = btrfs_super_generation(super_tmp);
 842                 superblock_tmp->is_metadata = 1;
 843                 superblock_tmp->is_superblock = 1;
 844                 superblock_tmp->is_iodone = 1;
 845                 superblock_tmp->never_written = 0;
 846                 superblock_tmp->mirror_num = 1 + superblock_mirror_num;
 847                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
 848                         printk_in_rcu(KERN_INFO "New initial S-block (bdev %p, %s)"
 849                                      " @%llu (%s/%llu/%d)\n",
 850                                      superblock_bdev,
 851                                      rcu_str_deref(device->name),
 852                                      (unsigned long long)dev_bytenr,
 853                                      dev_state->name,
 854                                      (unsigned long long)dev_bytenr,
 855                                      superblock_mirror_num);
 856                 list_add(&superblock_tmp->all_blocks_node,
 857                          &state->all_blocks_list);
 858                 btrfsic_block_hashtable_add(superblock_tmp,
 859                                             &state->block_hashtable);
 860         }
 861
 862         /* select the one with the highest generation field */
 863         if (btrfs_super_generation(super_tmp) >
 864             state->max_superblock_generation ||
 865             0 == state->max_superblock_generation) {
 866                 memcpy(selected_super, super_tmp, sizeof(*selected_super));
 867                 *selected_dev_state = dev_state;
 868                 state->max_superblock_generation =
 869                     btrfs_super_generation(super_tmp);
 870                 state->latest_superblock = superblock_tmp;
 871         }
 872
 873         for (pass = 0; pass < 3; pass++) {
 874                 u64 next_bytenr;
 875                 int num_copies;
 876                 int mirror_num;
 877                 const char *additional_string = NULL;
 878                 struct btrfs_disk_key tmp_disk_key;
 879
 880                 tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
 881                 tmp_disk_key.offset = 0;
 882                 switch (pass) {
 883                 case 0:
 884                         tmp_disk_key.objectid =
 885                             cpu_to_le64(BTRFS_ROOT_TREE_OBJECTID);
 886                         additional_string = "initial root ";
 887                         next_bytenr = btrfs_super_root(super_tmp);
 888                         break;
 889                 case 1:
 890                         tmp_disk_key.objectid =
 891                             cpu_to_le64(BTRFS_CHUNK_TREE_OBJECTID);
 892                         additional_string = "initial chunk ";
 893                         next_bytenr = btrfs_super_chunk_root(super_tmp);
 894                         break;
 895                 case 2:
 896                         tmp_disk_key.objectid =
 897                             cpu_to_le64(BTRFS_TREE_LOG_OBJECTID);
 898                         additional_string = "initial log ";
 899                         next_bytenr = btrfs_super_log_root(super_tmp);
 900                         if (0 == next_bytenr)
 901                                 continue;
 902                         break;
 903                 }
 904
 905                 num_copies =
 906                     btrfs_num_copies(state->root->fs_info,
 907                                      next_bytenr, state->metablock_size);
 908                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 909                         printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
 910                                (unsigned long long)next_bytenr, num_copies);
 911                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 912                         struct btrfsic_block *next_block;
 913                         struct btrfsic_block_data_ctx tmp_next_block_ctx;
 914                         struct btrfsic_block_link *l;
 915
 916                         if (btrfsic_map_block(state, next_bytenr,
 917                                               state->metablock_size,
 918                                               &tmp_next_block_ctx,
 919                                               mirror_num)) {
 920                                 printk(KERN_INFO "btrfsic: btrfsic_map_block("
 921                                        "bytenr @%llu, mirror %d) failed!\n",
 922                                        (unsigned long long)next_bytenr,
 923                                        mirror_num);
 924                                 brelse(bh);
 925                                 return -1;
 926                         }
 927
 928                         next_block = btrfsic_block_lookup_or_add(
 929                                         state, &tmp_next_block_ctx,
 930                                         additional_string, 1, 1, 0,
 931                                         mirror_num, NULL);
 932                         if (NULL == next_block) {
 933                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
 934                                 brelse(bh);
 935                                 return -1;
 936                         }
 937
 938                         next_block->disk_key = tmp_disk_key;
 939                         next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
 940                         l = btrfsic_block_link_lookup_or_add(
 941                                         state, &tmp_next_block_ctx,
 942                                         next_block, superblock_tmp,
 943                                         BTRFSIC_GENERATION_UNKNOWN);
 944                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
 945                         if (NULL == l) {
 946                                 brelse(bh);
 947                                 return -1;
 948                         }
 949                 }
 950         }
 951         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES)
 952                 btrfsic_dump_tree_sub(state, superblock_tmp, 0);
 953
 954         brelse(bh);
 955         return 0;
 956 }
 957
 958 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void)
 959 {
 960         struct btrfsic_stack_frame *sf;
 961
 962         sf = kzalloc(sizeof(*sf), GFP_NOFS);
 963         if (NULL == sf)
 964                 printk(KERN_INFO "btrfsic: alloc memory failed!\n");
 965         else
 966                 sf->magic = BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER;
 967         return sf;
 968 }
 969
 970 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf)
 971 {
 972         BUG_ON(!(NULL == sf ||
 973                  BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER == sf->magic));
 974         kfree(sf);
 975 }
 976
 977 static int btrfsic_process_metablock(
 978                 struct btrfsic_state *state,
 979                 struct btrfsic_block *const first_block,
 980                 struct btrfsic_block_data_ctx *const first_block_ctx,
 981                 int first_limit_nesting, int force_iodone_flag)
 982 {
 983         struct btrfsic_stack_frame initial_stack_frame = { 0 };
 984         struct btrfsic_stack_frame *sf;
 985         struct btrfsic_stack_frame *next_stack;
 986         struct btrfs_header *const first_hdr =
 987                 (struct btrfs_header *)first_block_ctx->datav[0];
 988
 989         BUG_ON(!first_hdr);
 990         sf = &initial_stack_frame;
 991         sf->error = 0;
 992         sf->i = -1;
 993         sf->limit_nesting = first_limit_nesting;
 994         sf->block = first_block;
 995         sf->block_ctx = first_block_ctx;
 996         sf->next_block = NULL;
 997         sf->hdr = first_hdr;
 998         sf->prev = NULL;
 999
1000 continue_with_new_stack_frame:
1001         sf->block->generation = le64_to_cpu(sf->hdr->generation);
1002         if (0 == sf->hdr->level) {
1003                 struct btrfs_leaf *const leafhdr =
1004                     (struct btrfs_leaf *)sf->hdr;
1005
1006                 if (-1 == sf->i) {
1007                         sf->nr = le32_to_cpu(leafhdr->header.nritems);
1008
1009                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1010                                 printk(KERN_INFO
1011                                        "leaf %llu items %d generation %llu"
1012                                        " owner %llu\n",
1013                                        (unsigned long long)
1014                                        sf->block_ctx->start,
1015                                        sf->nr,
1016                                        (unsigned long long)
1017                                        le64_to_cpu(leafhdr->header.generation),
1018                                        (unsigned long long)
1019                                        le64_to_cpu(leafhdr->header.owner));
1020                 }
1021
1022 continue_with_current_leaf_stack_frame:
1023                 if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1024                         sf->i++;
1025                         sf->num_copies = 0;
1026                 }
1027
1028                 if (sf->i < sf->nr) {
1029                         struct btrfs_item disk_item;
1030                         u32 disk_item_offset =
1031                                 (uintptr_t)(leafhdr->items + sf->i) -
1032                                 (uintptr_t)leafhdr;
1033                         struct btrfs_disk_key *disk_key;
1034                         u8 type;
1035                         u32 item_offset;
1036                         u32 item_size;
1037
1038                         if (disk_item_offset + sizeof(struct btrfs_item) >
1039                             sf->block_ctx->len) {
1040 leaf_item_out_of_bounce_error:
1041                                 printk(KERN_INFO
1042                                        "btrfsic: leaf item out of bounce at logical %llu, dev %s\n",
1043                                        sf->block_ctx->start,
1044                                        sf->block_ctx->dev->name);
1045                                 goto one_stack_frame_backwards;
1046                         }
1047                         btrfsic_read_from_block_data(sf->block_ctx,
1048                                                      &disk_item,
1049                                                      disk_item_offset,
1050                                                      sizeof(struct btrfs_item));
1051                         item_offset = le32_to_cpu(disk_item.offset);
1052                         item_size = le32_to_cpu(disk_item.size);
1053                         disk_key = &disk_item.key;
1054                         type = disk_key->type;
1055
1056                         if (BTRFS_ROOT_ITEM_KEY == type) {
1057                                 struct btrfs_root_item root_item;
1058                                 u32 root_item_offset;
1059                                 u64 next_bytenr;
1060
1061                                 root_item_offset = item_offset +
1062                                         offsetof(struct btrfs_leaf, items);
1063                                 if (root_item_offset + item_size >
1064                                     sf->block_ctx->len)
1065                                         goto leaf_item_out_of_bounce_error;
1066                                 btrfsic_read_from_block_data(
1067                                         sf->block_ctx, &root_item,
1068                                         root_item_offset,
1069                                         item_size);
1070                                 next_bytenr = le64_to_cpu(root_item.bytenr);
1071
1072                                 sf->error =
1073                                     btrfsic_create_link_to_next_block(
1074                                                 state,
1075                                                 sf->block,
1076                                                 sf->block_ctx,
1077                                                 next_bytenr,
1078                                                 sf->limit_nesting,
1079                                                 &sf->next_block_ctx,
1080                                                 &sf->next_block,
1081                                                 force_iodone_flag,
1082                                                 &sf->num_copies,
1083                                                 &sf->mirror_num,
1084                                                 disk_key,
1085                                                 le64_to_cpu(root_item.
1086                                                 generation));
1087                                 if (sf->error)
1088                                         goto one_stack_frame_backwards;
1089
1090                                 if (NULL != sf->next_block) {
1091                                         struct btrfs_header *const next_hdr =
1092                                             (struct btrfs_header *)
1093                                             sf->next_block_ctx.datav[0];
1094
1095                                         next_stack =
1096                                             btrfsic_stack_frame_alloc();
1097                                         if (NULL == next_stack) {
1098                                                 btrfsic_release_block_ctx(
1099                                                                 &sf->
1100                                                                 next_block_ctx);
1101                                                 goto one_stack_frame_backwards;
1102                                         }
1103
1104                                         next_stack->i = -1;
1105                                         next_stack->block = sf->next_block;
1106                                         next_stack->block_ctx =
1107                                             &sf->next_block_ctx;
1108                                         next_stack->next_block = NULL;
1109                                         next_stack->hdr = next_hdr;
1110                                         next_stack->limit_nesting =
1111                                             sf->limit_nesting - 1;
1112                                         next_stack->prev = sf;
1113                                         sf = next_stack;
1114                                         goto continue_with_new_stack_frame;
1115                                 }
1116                         } else if (BTRFS_EXTENT_DATA_KEY == type &&
1117                                    state->include_extent_data) {
1118                                 sf->error = btrfsic_handle_extent_data(
1119                                                 state,
1120                                                 sf->block,
1121                                                 sf->block_ctx,
1122                                                 item_offset,
1123                                                 force_iodone_flag);
1124                                 if (sf->error)
1125                                         goto one_stack_frame_backwards;
1126                         }
1127
1128                         goto continue_with_current_leaf_stack_frame;
1129                 }
1130         } else {
1131                 struct btrfs_node *const nodehdr = (struct btrfs_node *)sf->hdr;
1132
1133                 if (-1 == sf->i) {
1134                         sf->nr = le32_to_cpu(nodehdr->header.nritems);
1135
1136                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1137                                 printk(KERN_INFO "node %llu level %d items %d"
1138                                        " generation %llu owner %llu\n",
1139                                        (unsigned long long)
1140                                        sf->block_ctx->start,
1141                                        nodehdr->header.level, sf->nr,
1142                                        (unsigned long long)
1143                                        le64_to_cpu(nodehdr->header.generation),
1144                                        (unsigned long long)
1145                                        le64_to_cpu(nodehdr->header.owner));
1146                 }
1147
1148 continue_with_current_node_stack_frame:
1149                 if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1150                         sf->i++;
1151                         sf->num_copies = 0;
1152                 }
1153
1154                 if (sf->i < sf->nr) {
1155                         struct btrfs_key_ptr key_ptr;
1156                         u32 key_ptr_offset;
1157                         u64 next_bytenr;
1158
1159                         key_ptr_offset = (uintptr_t)(nodehdr->ptrs + sf->i) -
1160                                           (uintptr_t)nodehdr;
1161                         if (key_ptr_offset + sizeof(struct btrfs_key_ptr) >
1162                             sf->block_ctx->len) {
1163                                 printk(KERN_INFO
1164                                        "btrfsic: node item out of bounce at logical %llu, dev %s\n",
1165                                        sf->block_ctx->start,
1166                                        sf->block_ctx->dev->name);
1167                                 goto one_stack_frame_backwards;
1168                         }
1169                         btrfsic_read_from_block_data(
1170                                 sf->block_ctx, &key_ptr, key_ptr_offset,
1171                                 sizeof(struct btrfs_key_ptr));
1172                         next_bytenr = le64_to_cpu(key_ptr.blockptr);
1173
1174                         sf->error = btrfsic_create_link_to_next_block(
1175                                         state,
1176                                         sf->block,
1177                                         sf->block_ctx,
1178                                         next_bytenr,
1179                                         sf->limit_nesting,
1180                                         &sf->next_block_ctx,
1181                                         &sf->next_block,
1182                                         force_iodone_flag,
1183                                         &sf->num_copies,
1184                                         &sf->mirror_num,
1185                                         &key_ptr.key,
1186                                         le64_to_cpu(key_ptr.generation));
1187                         if (sf->error)
1188                                 goto one_stack_frame_backwards;
1189
1190                         if (NULL != sf->next_block) {
1191                                 struct btrfs_header *const next_hdr =
1192                                     (struct btrfs_header *)
1193                                     sf->next_block_ctx.datav[0];
1194
1195                                 next_stack = btrfsic_stack_frame_alloc();
1196                                 if (NULL == next_stack)
1197                                         goto one_stack_frame_backwards;
1198
1199                                 next_stack->i = -1;
1200                                 next_stack->block = sf->next_block;
1201                                 next_stack->block_ctx = &sf->next_block_ctx;
1202                                 next_stack->next_block = NULL;
1203                                 next_stack->hdr = next_hdr;
1204                                 next_stack->limit_nesting =
1205                                     sf->limit_nesting - 1;
1206                                 next_stack->prev = sf;
1207                                 sf = next_stack;
1208                                 goto continue_with_new_stack_frame;
1209                         }
1210
1211                         goto continue_with_current_node_stack_frame;
1212                 }
1213         }
1214
1215 one_stack_frame_backwards:
1216         if (NULL != sf->prev) {
1217                 struct btrfsic_stack_frame *const prev = sf->prev;
1218
1219                 /* the one for the initial block is freed in the caller */
1220                 btrfsic_release_block_ctx(sf->block_ctx);
1221
1222                 if (sf->error) {
1223                         prev->error = sf->error;
1224                         btrfsic_stack_frame_free(sf);
1225                         sf = prev;
1226                         goto one_stack_frame_backwards;
1227                 }
1228
1229                 btrfsic_stack_frame_free(sf);
1230                 sf = prev;
1231                 goto continue_with_new_stack_frame;
1232         } else {
1233                 BUG_ON(&initial_stack_frame != sf);
1234         }
1235
1236         return sf->error;
1237 }
1238
1239 static void btrfsic_read_from_block_data(
1240         struct btrfsic_block_data_ctx *block_ctx,
1241         void *dstv, u32 offset, size_t len)
1242 {
1243         size_t cur;
1244         size_t offset_in_page;
1245         char *kaddr;
1246         char *dst = (char *)dstv;
1247         size_t start_offset = block_ctx->start & ((u64)PAGE_CACHE_SIZE - 1);
1248         unsigned long i = (start_offset + offset) >> PAGE_CACHE_SHIFT;
1249
1250         WARN_ON(offset + len > block_ctx->len);
1251         offset_in_page = (start_offset + offset) &
1252                          ((unsigned long)PAGE_CACHE_SIZE - 1);
1253
1254         while (len > 0) {
1255                 cur = min(len, ((size_t)PAGE_CACHE_SIZE - offset_in_page));
1256                 BUG_ON(i >= (block_ctx->len + PAGE_CACHE_SIZE - 1) >>
1257                             PAGE_CACHE_SHIFT);
1258                 kaddr = block_ctx->datav[i];
1259                 memcpy(dst, kaddr + offset_in_page, cur);
1260
1261                 dst += cur;
1262                 len -= cur;
1263                 offset_in_page = 0;
1264                 i++;
1265         }
1266 }
1267
1268 static int btrfsic_create_link_to_next_block(
1269                 struct btrfsic_state *state,
1270                 struct btrfsic_block *block,
1271                 struct btrfsic_block_data_ctx *block_ctx,
1272                 u64 next_bytenr,
1273                 int limit_nesting,
1274                 struct btrfsic_block_data_ctx *next_block_ctx,
1275                 struct btrfsic_block **next_blockp,
1276                 int force_iodone_flag,
1277                 int *num_copiesp, int *mirror_nump,
1278                 struct btrfs_disk_key *disk_key,
1279                 u64 parent_generation)
1280 {
1281         struct btrfsic_block *next_block = NULL;
1282         int ret;
1283         struct btrfsic_block_link *l;
1284         int did_alloc_block_link;
1285         int block_was_created;
1286
1287         *next_blockp = NULL;
1288         if (0 == *num_copiesp) {
1289                 *num_copiesp =
1290                     btrfs_num_copies(state->root->fs_info,
1291                                      next_bytenr, state->metablock_size);
1292                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1293                         printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1294                                (unsigned long long)next_bytenr, *num_copiesp);
1295                 *mirror_nump = 1;
1296         }
1297
1298         if (*mirror_nump > *num_copiesp)
1299                 return 0;
1300
1301         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1302                 printk(KERN_INFO
1303                        "btrfsic_create_link_to_next_block(mirror_num=%d)\n",
1304                        *mirror_nump);
1305         ret = btrfsic_map_block(state, next_bytenr,
1306                                 state->metablock_size,
1307                                 next_block_ctx, *mirror_nump);
1308         if (ret) {
1309                 printk(KERN_INFO
1310                        "btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1311                        (unsigned long long)next_bytenr, *mirror_nump);
1312                 btrfsic_release_block_ctx(next_block_ctx);
1313                 *next_blockp = NULL;
1314                 return -1;
1315         }
1316
1317         next_block = btrfsic_block_lookup_or_add(state,
1318                                                  next_block_ctx, "referenced ",
1319                                                  1, force_iodone_flag,
1320                                                  !force_iodone_flag,
1321                                                  *mirror_nump,
1322                                                  &block_was_created);
1323         if (NULL == next_block) {
1324                 btrfsic_release_block_ctx(next_block_ctx);
1325                 *next_blockp = NULL;
1326                 return -1;
1327         }
1328         if (block_was_created) {
1329                 l = NULL;
1330                 next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
1331         } else {
1332                 if (next_block->logical_bytenr != next_bytenr &&
1333                     !(!next_block->is_metadata &&
1334                       0 == next_block->logical_bytenr)) {
1335                         printk(KERN_INFO
1336                                "Referenced block @%llu (%s/%llu/%d)"
1337                                " found in hash table, %c,"
1338                                " bytenr mismatch (!= stored %llu).\n",
1339                                (unsigned long long)next_bytenr,
1340                                next_block_ctx->dev->name,
1341                                (unsigned long long)next_block_ctx->dev_bytenr,
1342                                *mirror_nump,
1343                                btrfsic_get_block_type(state, next_block),
1344                                (unsigned long long)next_block->logical_bytenr);
1345                 } else if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1346                         printk(KERN_INFO
1347                                "Referenced block @%llu (%s/%llu/%d)"
1348                                " found in hash table, %c.\n",
1349                                (unsigned long long)next_bytenr,
1350                                next_block_ctx->dev->name,
1351                                (unsigned long long)next_block_ctx->dev_bytenr,
1352                                *mirror_nump,
1353                                btrfsic_get_block_type(state, next_block));
1354                 next_block->logical_bytenr = next_bytenr;
1355
1356                 next_block->mirror_num = *mirror_nump;
1357                 l = btrfsic_block_link_hashtable_lookup(
1358                                 next_block_ctx->dev->bdev,
1359                                 next_block_ctx->dev_bytenr,
1360                                 block_ctx->dev->bdev,
1361                                 block_ctx->dev_bytenr,
1362                                 &state->block_link_hashtable);
1363         }
1364
1365         next_block->disk_key = *disk_key;
1366         if (NULL == l) {
1367                 l = btrfsic_block_link_alloc();
1368                 if (NULL == l) {
1369                         printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
1370                         btrfsic_release_block_ctx(next_block_ctx);
1371                         *next_blockp = NULL;
1372                         return -1;
1373                 }
1374
1375                 did_alloc_block_link = 1;
1376                 l->block_ref_to = next_block;
1377                 l->block_ref_from = block;
1378                 l->ref_cnt = 1;
1379                 l->parent_generation = parent_generation;
1380
1381                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1382                         btrfsic_print_add_link(state, l);
1383
1384                 list_add(&l->node_ref_to, &block->ref_to_list);
1385                 list_add(&l->node_ref_from, &next_block->ref_from_list);
1386
1387                 btrfsic_block_link_hashtable_add(l,
1388                                                  &state->block_link_hashtable);
1389         } else {
1390                 did_alloc_block_link = 0;
1391                 if (0 == limit_nesting) {
1392                         l->ref_cnt++;
1393                         l->parent_generation = parent_generation;
1394                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1395                                 btrfsic_print_add_link(state, l);
1396                 }
1397         }
1398
1399         if (limit_nesting > 0 && did_alloc_block_link) {
1400                 ret = btrfsic_read_block(state, next_block_ctx);
1401                 if (ret < (int)next_block_ctx->len) {
1402                         printk(KERN_INFO
1403                                "btrfsic: read block @logical %llu failed!\n",
1404                                (unsigned long long)next_bytenr);
1405                         btrfsic_release_block_ctx(next_block_ctx);
1406                         *next_blockp = NULL;
1407                         return -1;
1408                 }
1409
1410                 *next_blockp = next_block;
1411         } else {
1412                 *next_blockp = NULL;
1413         }
1414         (*mirror_nump)++;
1415
1416         return 0;
1417 }
1418
1419 static int btrfsic_handle_extent_data(
1420                 struct btrfsic_state *state,
1421                 struct btrfsic_block *block,
1422                 struct btrfsic_block_data_ctx *block_ctx,
1423                 u32 item_offset, int force_iodone_flag)
1424 {
1425         int ret;
1426         struct btrfs_file_extent_item file_extent_item;
1427         u64 file_extent_item_offset;
1428         u64 next_bytenr;
1429         u64 num_bytes;
1430         u64 generation;
1431         struct btrfsic_block_link *l;
1432
1433         file_extent_item_offset = offsetof(struct btrfs_leaf, items) +
1434                                   item_offset;
1435         if (file_extent_item_offset +
1436             offsetof(struct btrfs_file_extent_item, disk_num_bytes) >
1437             block_ctx->len) {
1438                 printk(KERN_INFO
1439                        "btrfsic: file item out of bounce at logical %llu, dev %s\n",
1440                        block_ctx->start, block_ctx->dev->name);
1441                 return -1;
1442         }
1443
1444         btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1445                 file_extent_item_offset,
1446                 offsetof(struct btrfs_file_extent_item, disk_num_bytes));
1447         if (BTRFS_FILE_EXTENT_REG != file_extent_item.type ||
1448             ((u64)0) == le64_to_cpu(file_extent_item.disk_bytenr)) {
1449                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1450                         printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu\n",
1451                                file_extent_item.type,
1452                                (unsigned long long)
1453                                le64_to_cpu(file_extent_item.disk_bytenr));
1454                 return 0;
1455         }
1456
1457         if (file_extent_item_offset + sizeof(struct btrfs_file_extent_item) >
1458             block_ctx->len) {
1459                 printk(KERN_INFO
1460                        "btrfsic: file item out of bounce at logical %llu, dev %s\n",
1461                        block_ctx->start, block_ctx->dev->name);
1462                 return -1;
1463         }
1464         btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1465                                      file_extent_item_offset,
1466                                      sizeof(struct btrfs_file_extent_item));
1467         next_bytenr = le64_to_cpu(file_extent_item.disk_bytenr) +
1468                       le64_to_cpu(file_extent_item.offset);
1469         generation = le64_to_cpu(file_extent_item.generation);
1470         num_bytes = le64_to_cpu(file_extent_item.num_bytes);
1471         generation = le64_to_cpu(file_extent_item.generation);
1472
1473         if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1474                 printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu,"
1475                        " offset = %llu, num_bytes = %llu\n",
1476                        file_extent_item.type,
1477                        (unsigned long long)
1478                        le64_to_cpu(file_extent_item.disk_bytenr),
1479                        (unsigned long long)le64_to_cpu(file_extent_item.offset),
1480                        (unsigned long long)num_bytes);
1481         while (num_bytes > 0) {
1482                 u32 chunk_len;
1483                 int num_copies;
1484                 int mirror_num;
1485
1486                 if (num_bytes > state->datablock_size)
1487                         chunk_len = state->datablock_size;
1488                 else
1489                         chunk_len = num_bytes;
1490
1491                 num_copies =
1492                     btrfs_num_copies(state->root->fs_info,
1493                                      next_bytenr, state->datablock_size);
1494                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1495                         printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1496                                (unsigned long long)next_bytenr, num_copies);
1497                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
1498                         struct btrfsic_block_data_ctx next_block_ctx;
1499                         struct btrfsic_block *next_block;
1500                         int block_was_created;
1501
1502                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1503                                 printk(KERN_INFO "btrfsic_handle_extent_data("
1504                                        "mirror_num=%d)\n", mirror_num);
1505                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1506                                 printk(KERN_INFO
1507                                        "\tdisk_bytenr = %llu, num_bytes %u\n",
1508                                        (unsigned long long)next_bytenr,
1509                                        chunk_len);
1510                         ret = btrfsic_map_block(state, next_bytenr,
1511                                                 chunk_len, &next_block_ctx,
1512                                                 mirror_num);
1513                         if (ret) {
1514                                 printk(KERN_INFO
1515                                        "btrfsic: btrfsic_map_block(@%llu,"
1516                                        " mirror=%d) failed!\n",
1517                                        (unsigned long long)next_bytenr,
1518                                        mirror_num);
1519                                 return -1;
1520                         }
1521
1522                         next_block = btrfsic_block_lookup_or_add(
1523                                         state,
1524                                         &next_block_ctx,
1525                                         "referenced ",
1526                                         0,
1527                                         force_iodone_flag,
1528                                         !force_iodone_flag,
1529                                         mirror_num,
1530                                         &block_was_created);
1531                         if (NULL == next_block) {
1532                                 printk(KERN_INFO
1533                                        "btrfsic: error, kmalloc failed!\n");
1534                                 btrfsic_release_block_ctx(&next_block_ctx);
1535                                 return -1;
1536                         }
1537                         if (!block_was_created) {
1538                                 if (next_block->logical_bytenr != next_bytenr &&
1539                                     !(!next_block->is_metadata &&
1540                                       0 == next_block->logical_bytenr)) {
1541                                         printk(KERN_INFO
1542                                                "Referenced block"
1543                                                " @%llu (%s/%llu/%d)"
1544                                                " found in hash table, D,"
1545                                                " bytenr mismatch"
1546                                                " (!= stored %llu).\n",
1547                                                (unsigned long long)next_bytenr,
1548                                                next_block_ctx.dev->name,
1549                                                (unsigned long long)
1550                                                next_block_ctx.dev_bytenr,
1551                                                mirror_num,
1552                                                (unsigned long long)
1553                                                next_block->logical_bytenr);
1554                                 }
1555                                 next_block->logical_bytenr = next_bytenr;
1556                                 next_block->mirror_num = mirror_num;
1557                         }
1558
1559                         l = btrfsic_block_link_lookup_or_add(state,
1560                                                              &next_block_ctx,
1561                                                              next_block, block,
1562                                                              generation);
1563                         btrfsic_release_block_ctx(&next_block_ctx);
1564                         if (NULL == l)
1565                                 return -1;
1566                 }
1567
1568                 next_bytenr += chunk_len;
1569                 num_bytes -= chunk_len;
1570         }
1571
1572         return 0;
1573 }
1574
1575 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
1576                              struct btrfsic_block_data_ctx *block_ctx_out,
1577                              int mirror_num)
1578 {
1579         int ret;
1580         u64 length;
1581         struct btrfs_bio *multi = NULL;
1582         struct btrfs_device *device;
1583
1584         length = len;
1585         ret = btrfs_map_block(state->root->fs_info, READ,
1586                               bytenr, &length, &multi, mirror_num);
1587
1588         if (ret) {
1589                 block_ctx_out->start = 0;
1590                 block_ctx_out->dev_bytenr = 0;
1591                 block_ctx_out->len = 0;
1592                 block_ctx_out->dev = NULL;
1593                 block_ctx_out->datav = NULL;
1594                 block_ctx_out->pagev = NULL;
1595                 block_ctx_out->mem_to_free = NULL;
1596
1597                 return ret;
1598         }
1599
1600         device = multi->stripes[0].dev;
1601         block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev);
1602         block_ctx_out->dev_bytenr = multi->stripes[0].physical;
1603         block_ctx_out->start = bytenr;
1604         block_ctx_out->len = len;
1605         block_ctx_out->datav = NULL;
1606         block_ctx_out->pagev = NULL;
1607         block_ctx_out->mem_to_free = NULL;
1608
1609         kfree(multi);
1610         if (NULL == block_ctx_out->dev) {
1611                 ret = -ENXIO;
1612                 printk(KERN_INFO "btrfsic: error, cannot lookup dev (#1)!\n");
1613         }
1614
1615         return ret;
1616 }
1617
1618 static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
1619                                   u32 len, struct block_device *bdev,
1620                                   struct btrfsic_block_data_ctx *block_ctx_out)
1621 {
1622         block_ctx_out->dev = btrfsic_dev_state_lookup(bdev);
1623         block_ctx_out->dev_bytenr = bytenr;
1624         block_ctx_out->start = bytenr;
1625         block_ctx_out->len = len;
1626         block_ctx_out->datav = NULL;
1627         block_ctx_out->pagev = NULL;
1628         block_ctx_out->mem_to_free = NULL;
1629         if (NULL != block_ctx_out->dev) {
1630                 return 0;
1631         } else {
1632                 printk(KERN_INFO "btrfsic: error, cannot lookup dev (#2)!\n");
1633                 return -ENXIO;
1634         }
1635 }
1636
1637 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
1638 {
1639         if (block_ctx->mem_to_free) {
1640                 unsigned int num_pages;
1641
1642                 BUG_ON(!block_ctx->datav);
1643                 BUG_ON(!block_ctx->pagev);
1644                 num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
1645                             PAGE_CACHE_SHIFT;
1646                 while (num_pages > 0) {
1647                         num_pages--;
1648                         if (block_ctx->datav[num_pages]) {
1649                                 kunmap(block_ctx->pagev[num_pages]);
1650                                 block_ctx->datav[num_pages] = NULL;
1651                         }
1652                         if (block_ctx->pagev[num_pages]) {
1653                                 __free_page(block_ctx->pagev[num_pages]);
1654                                 block_ctx->pagev[num_pages] = NULL;
1655                         }
1656                 }
1657
1658                 kfree(block_ctx->mem_to_free);
1659                 block_ctx->mem_to_free = NULL;
1660                 block_ctx->pagev = NULL;
1661                 block_ctx->datav = NULL;
1662         }
1663 }
1664
1665 static int btrfsic_read_block(struct btrfsic_state *state,
1666                               struct btrfsic_block_data_ctx *block_ctx)
1667 {
1668         unsigned int num_pages;
1669         unsigned int i;
1670         u64 dev_bytenr;
1671         int ret;
1672
1673         BUG_ON(block_ctx->datav);
1674         BUG_ON(block_ctx->pagev);
1675         BUG_ON(block_ctx->mem_to_free);
1676         if (block_ctx->dev_bytenr & ((u64)PAGE_CACHE_SIZE - 1)) {
1677                 printk(KERN_INFO
1678                        "btrfsic: read_block() with unaligned bytenr %llu\n",
1679                        (unsigned long long)block_ctx->dev_bytenr);
1680                 return -1;
1681         }
1682
1683         num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
1684                     PAGE_CACHE_SHIFT;
1685         block_ctx->mem_to_free = kzalloc((sizeof(*block_ctx->datav) +
1686                                           sizeof(*block_ctx->pagev)) *
1687                                          num_pages, GFP_NOFS);
1688         if (!block_ctx->mem_to_free)
1689                 return -1;
1690         block_ctx->datav = block_ctx->mem_to_free;
1691         block_ctx->pagev = (struct page **)(block_ctx->datav + num_pages);
1692         for (i = 0; i < num_pages; i++) {
1693                 block_ctx->pagev[i] = alloc_page(GFP_NOFS);
1694                 if (!block_ctx->pagev[i])
1695                         return -1;
1696         }
1697
1698         dev_bytenr = block_ctx->dev_bytenr;
1699         for (i = 0; i < num_pages;) {
1700                 struct bio *bio;
1701                 unsigned int j;
1702                 DECLARE_COMPLETION_ONSTACK(complete);
1703
1704                 bio = bio_alloc(GFP_NOFS, num_pages - i);
1705                 if (!bio) {
1706                         printk(KERN_INFO
1707                                "btrfsic: bio_alloc() for %u pages failed!\n",
1708                                num_pages - i);
1709                         return -1;
1710                 }
1711                 bio->bi_bdev = block_ctx->dev->bdev;
1712                 bio->bi_sector = dev_bytenr >> 9;
1713                 bio->bi_end_io = btrfsic_complete_bio_end_io;
1714                 bio->bi_private = &complete;
1715
1716                 for (j = i; j < num_pages; j++) {
1717                         ret = bio_add_page(bio, block_ctx->pagev[j],
1718                                            PAGE_CACHE_SIZE, 0);
1719                         if (PAGE_CACHE_SIZE != ret)
1720                                 break;
1721                 }
1722                 if (j == i) {
1723                         printk(KERN_INFO
1724                                "btrfsic: error, failed to add a single page!\n");
1725                         return -1;
1726                 }
1727                 submit_bio(READ, bio);
1728
1729                 /* this will also unplug the queue */
1730                 wait_for_completion(&complete);
1731
1732                 if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
1733                         printk(KERN_INFO
1734                                "btrfsic: read error at logical %llu dev %s!\n",
1735                                block_ctx->start, block_ctx->dev->name);
1736                         bio_put(bio);
1737                         return -1;
1738                 }
1739                 bio_put(bio);
1740                 dev_bytenr += (j - i) * PAGE_CACHE_SIZE;
1741                 i = j;
1742         }
1743         for (i = 0; i < num_pages; i++) {
1744                 block_ctx->datav[i] = kmap(block_ctx->pagev[i]);
1745                 if (!block_ctx->datav[i]) {
1746                         printk(KERN_INFO "btrfsic: kmap() failed (dev %s)!\n",
1747                                block_ctx->dev->name);
1748                         return -1;
1749                 }
1750         }
1751
1752         return block_ctx->len;
1753 }
1754
1755 static void btrfsic_complete_bio_end_io(struct bio *bio, int err)
1756 {
1757         complete((struct completion *)bio->bi_private);
1758 }
1759
1760 static void btrfsic_dump_database(struct btrfsic_state *state)
1761 {
1762         struct list_head *elem_all;
1763
1764         BUG_ON(NULL == state);
1765
1766         printk(KERN_INFO "all_blocks_list:\n");
1767         list_for_each(elem_all, &state->all_blocks_list) {
1768                 const struct btrfsic_block *const b_all =
1769                     list_entry(elem_all, struct btrfsic_block,
1770                                all_blocks_node);
1771                 struct list_head *elem_ref_to;
1772                 struct list_head *elem_ref_from;
1773
1774                 printk(KERN_INFO "%c-block @%llu (%s/%llu/%d)\n",
1775                        btrfsic_get_block_type(state, b_all),
1776                        (unsigned long long)b_all->logical_bytenr,
1777                        b_all->dev_state->name,
1778                        (unsigned long long)b_all->dev_bytenr,
1779                        b_all->mirror_num);
1780
1781                 list_for_each(elem_ref_to, &b_all->ref_to_list) {
1782                         const struct btrfsic_block_link *const l =
1783                             list_entry(elem_ref_to,
1784                                        struct btrfsic_block_link,
1785                                        node_ref_to);
1786
1787                         printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1788                                " refers %u* to"
1789                                " %c @%llu (%s/%llu/%d)\n",
1790                                btrfsic_get_block_type(state, b_all),
1791                                (unsigned long long)b_all->logical_bytenr,
1792                                b_all->dev_state->name,
1793                                (unsigned long long)b_all->dev_bytenr,
1794                                b_all->mirror_num,
1795                                l->ref_cnt,
1796                                btrfsic_get_block_type(state, l->block_ref_to),
1797                                (unsigned long long)
1798                                l->block_ref_to->logical_bytenr,
1799                                l->block_ref_to->dev_state->name,
1800                                (unsigned long long)l->block_ref_to->dev_bytenr,
1801                                l->block_ref_to->mirror_num);
1802                 }
1803
1804                 list_for_each(elem_ref_from, &b_all->ref_from_list) {
1805                         const struct btrfsic_block_link *const l =
1806                             list_entry(elem_ref_from,
1807                                        struct btrfsic_block_link,
1808                                        node_ref_from);
1809
1810                         printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1811                                " is ref %u* from"
1812                                " %c @%llu (%s/%llu/%d)\n",
1813                                btrfsic_get_block_type(state, b_all),
1814                                (unsigned long long)b_all->logical_bytenr,
1815                                b_all->dev_state->name,
1816                                (unsigned long long)b_all->dev_bytenr,
1817                                b_all->mirror_num,
1818                                l->ref_cnt,
1819                                btrfsic_get_block_type(state, l->block_ref_from),
1820                                (unsigned long long)
1821                                l->block_ref_from->logical_bytenr,
1822                                l->block_ref_from->dev_state->name,
1823                                (unsigned long long)
1824                                l->block_ref_from->dev_bytenr,
1825                                l->block_ref_from->mirror_num);
1826                 }
1827
1828                 printk(KERN_INFO "\n");
1829         }
1830 }
1831
1832 /*
1833  * Test whether the disk block contains a tree block (leaf or node)
1834  * (note that this test fails for the super block)
1835  */
1836 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
1837                                      char **datav, unsigned int num_pages)
1838 {
1839         struct btrfs_header *h;
1840         u8 csum[BTRFS_CSUM_SIZE];
1841         u32 crc = ~(u32)0;
1842         unsigned int i;
1843
1844         if (num_pages * PAGE_CACHE_SIZE < state->metablock_size)
1845                 return 1; /* not metadata */
1846         num_pages = state->metablock_size >> PAGE_CACHE_SHIFT;
1847         h = (struct btrfs_header *)datav[0];
1848
1849         if (memcmp(h->fsid, state->root->fs_info->fsid, BTRFS_UUID_SIZE))
1850                 return 1;
1851
1852         for (i = 0; i < num_pages; i++) {
1853                 u8 *data = i ? datav[i] : (datav[i] + BTRFS_CSUM_SIZE);
1854                 size_t sublen = i ? PAGE_CACHE_SIZE :
1855                                     (PAGE_CACHE_SIZE - BTRFS_CSUM_SIZE);
1856
1857                 crc = crc32c(crc, data, sublen);
1858         }
1859         btrfs_csum_final(crc, csum);
1860         if (memcmp(csum, h->csum, state->csum_size))
1861                 return 1;
1862
1863         return 0; /* is metadata */
1864 }
1865
1866 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
1867                                           u64 dev_bytenr, char **mapped_datav,
1868                                           unsigned int num_pages,
1869                                           struct bio *bio, int *bio_is_patched,
1870                                           struct buffer_head *bh,
1871                                           int submit_bio_bh_rw)
1872 {
1873         int is_metadata;
1874         struct btrfsic_block *block;
1875         struct btrfsic_block_data_ctx block_ctx;
1876         int ret;
1877         struct btrfsic_state *state = dev_state->state;
1878         struct block_device *bdev = dev_state->bdev;
1879         unsigned int processed_len;
1880
1881         if (NULL != bio_is_patched)
1882                 *bio_is_patched = 0;
1883
1884 again:
1885         if (num_pages == 0)
1886                 return;
1887
1888         processed_len = 0;
1889         is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_datav,
1890                                                       num_pages));
1891
1892         block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
1893                                                &state->block_hashtable);
1894         if (NULL != block) {
1895                 u64 bytenr = 0;
1896                 struct list_head *elem_ref_to;
1897                 struct list_head *tmp_ref_to;
1898
1899                 if (block->is_superblock) {
1900                         bytenr = le64_to_cpu(((struct btrfs_super_block *)
1901                                               mapped_datav[0])->bytenr);
1902                         if (num_pages * PAGE_CACHE_SIZE <
1903                             BTRFS_SUPER_INFO_SIZE) {
1904                                 printk(KERN_INFO
1905                                        "btrfsic: cannot work with too short bios!\n");
1906                                 return;
1907                         }
1908                         is_metadata = 1;
1909                         BUG_ON(BTRFS_SUPER_INFO_SIZE & (PAGE_CACHE_SIZE - 1));
1910                         processed_len = BTRFS_SUPER_INFO_SIZE;
1911                         if (state->print_mask &
1912                             BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
1913                                 printk(KERN_INFO
1914                                        "[before new superblock is written]:\n");
1915                                 btrfsic_dump_tree_sub(state, block, 0);
1916                         }
1917                 }
1918                 if (is_metadata) {
1919                         if (!block->is_superblock) {
1920                                 if (num_pages * PAGE_CACHE_SIZE <
1921                                     state->metablock_size) {
1922                                         printk(KERN_INFO
1923                                                "btrfsic: cannot work with too short bios!\n");
1924                                         return;
1925                                 }
1926                                 processed_len = state->metablock_size;
1927                                 bytenr = le64_to_cpu(((struct btrfs_header *)
1928                                                       mapped_datav[0])->bytenr);
1929                                 btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
1930                                                                dev_state,
1931                                                                dev_bytenr);
1932                         }
1933                         if (block->logical_bytenr != bytenr) {
1934                                 printk(KERN_INFO
1935                                        "Written block @%llu (%s/%llu/%d)"
1936                                        " found in hash table, %c,"
1937                                        " bytenr mismatch"
1938                                        " (!= stored %llu).\n",
1939                                        (unsigned long long)bytenr,
1940                                        dev_state->name,
1941                                        (unsigned long long)dev_bytenr,
1942                                        block->mirror_num,
1943                                        btrfsic_get_block_type(state, block),
1944                                        (unsigned long long)
1945                                        block->logical_bytenr);
1946                                 block->logical_bytenr = bytenr;
1947                         } else if (state->print_mask &
1948                                    BTRFSIC_PRINT_MASK_VERBOSE)
1949                                 printk(KERN_INFO
1950                                        "Written block @%llu (%s/%llu/%d)"
1951                                        " found in hash table, %c.\n",
1952                                        (unsigned long long)bytenr,
1953                                        dev_state->name,
1954                                        (unsigned long long)dev_bytenr,
1955                                        block->mirror_num,
1956                                        btrfsic_get_block_type(state, block));
1957                 } else {
1958                         if (num_pages * PAGE_CACHE_SIZE <
1959                             state->datablock_size) {
1960                                 printk(KERN_INFO
1961                                        "btrfsic: cannot work with too short bios!\n");
1962                                 return;
1963                         }
1964                         processed_len = state->datablock_size;
1965                         bytenr = block->logical_bytenr;
1966                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1967                                 printk(KERN_INFO
1968                                        "Written block @%llu (%s/%llu/%d)"
1969                                        " found in hash table, %c.\n",
1970                                        (unsigned long long)bytenr,
1971                                        dev_state->name,
1972                                        (unsigned long long)dev_bytenr,
1973                                        block->mirror_num,
1974                                        btrfsic_get_block_type(state, block));
1975                 }
1976
1977                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1978                         printk(KERN_INFO
1979                                "ref_to_list: %cE, ref_from_list: %cE\n",
1980                                list_empty(&block->ref_to_list) ? ' ' : '!',
1981                                list_empty(&block->ref_from_list) ? ' ' : '!');
1982                 if (btrfsic_is_block_ref_by_superblock(state, block, 0)) {
1983                         printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
1984                                " @%llu (%s/%llu/%d), old(gen=%llu,"
1985                                " objectid=%llu, type=%d, offset=%llu),"
1986                                " new(gen=%llu),"
1987                                " which is referenced by most recent superblock"
1988                                " (superblockgen=%llu)!\n",
1989                                btrfsic_get_block_type(state, block),
1990                                (unsigned long long)bytenr,
1991                                dev_state->name,
1992                                (unsigned long long)dev_bytenr,
1993                                block->mirror_num,
1994                                (unsigned long long)block->generation,
1995                                (unsigned long long)
1996                                le64_to_cpu(block->disk_key.objectid),
1997                                block->disk_key.type,
1998                                (unsigned long long)
1999                                le64_to_cpu(block->disk_key.offset),
2000                                (unsigned long long)
2001                                le64_to_cpu(((struct btrfs_header *)
2002                                             mapped_datav[0])->generation),
2003                                (unsigned long long)
2004                                state->max_superblock_generation);
2005                         btrfsic_dump_tree(state);
2006                 }
2007
2008                 if (!block->is_iodone && !block->never_written) {
2009                         printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
2010                                " @%llu (%s/%llu/%d), oldgen=%llu, newgen=%llu,"
2011                                " which is not yet iodone!\n",
2012                                btrfsic_get_block_type(state, block),
2013                                (unsigned long long)bytenr,
2014                                dev_state->name,
2015                                (unsigned long long)dev_bytenr,
2016                                block->mirror_num,
2017                                (unsigned long long)block->generation,
2018                                (unsigned long long)
2019                                le64_to_cpu(((struct btrfs_header *)
2020                                             mapped_datav[0])->generation));
2021                         /* it would not be safe to go on */
2022                         btrfsic_dump_tree(state);
2023                         goto continue_loop;
2024                 }
2025
2026                 /*
2027                  * Clear all references of this block. Do not free
2028                  * the block itself even if is not referenced anymore
2029                  * because it still carries valueable information
2030                  * like whether it was ever written and IO completed.
2031                  */
2032                 list_for_each_safe(elem_ref_to, tmp_ref_to,
2033                                    &block->ref_to_list) {
2034                         struct btrfsic_block_link *const l =
2035                             list_entry(elem_ref_to,
2036                                        struct btrfsic_block_link,
2037                                        node_ref_to);
2038
2039                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2040                                 btrfsic_print_rem_link(state, l);
2041                         l->ref_cnt--;
2042                         if (0 == l->ref_cnt) {
2043                                 list_del(&l->node_ref_to);
2044                                 list_del(&l->node_ref_from);
2045                                 btrfsic_block_link_hashtable_remove(l);
2046                                 btrfsic_block_link_free(l);
2047                         }
2048                 }
2049
2050                 if (block->is_superblock)
2051                         ret = btrfsic_map_superblock(state, bytenr,
2052                                                      processed_len,
2053                                                      bdev, &block_ctx);
2054                 else
2055                         ret = btrfsic_map_block(state, bytenr, processed_len,
2056                                                 &block_ctx, 0);
2057                 if (ret) {
2058                         printk(KERN_INFO
2059                                "btrfsic: btrfsic_map_block(root @%llu)"
2060                                " failed!\n", (unsigned long long)bytenr);
2061                         goto continue_loop;
2062                 }
2063                 block_ctx.datav = mapped_datav;
2064                 /* the following is required in case of writes to mirrors,
2065                  * use the same that was used for the lookup */
2066                 block_ctx.dev = dev_state;
2067                 block_ctx.dev_bytenr = dev_bytenr;
2068
2069                 if (is_metadata || state->include_extent_data) {
2070                         block->never_written = 0;
2071                         block->iodone_w_error = 0;
2072                         if (NULL != bio) {
2073                                 block->is_iodone = 0;
2074                                 BUG_ON(NULL == bio_is_patched);
2075                                 if (!*bio_is_patched) {
2076                                         block->orig_bio_bh_private =
2077                                             bio->bi_private;
2078                                         block->orig_bio_bh_end_io.bio =
2079                                             bio->bi_end_io;
2080                                         block->next_in_same_bio = NULL;
2081                                         bio->bi_private = block;
2082                                         bio->bi_end_io = btrfsic_bio_end_io;
2083                                         *bio_is_patched = 1;
2084                                 } else {
2085                                         struct btrfsic_block *chained_block =
2086                                             (struct btrfsic_block *)
2087                                             bio->bi_private;
2088
2089                                         BUG_ON(NULL == chained_block);
2090                                         block->orig_bio_bh_private =
2091                                             chained_block->orig_bio_bh_private;
2092                                         block->orig_bio_bh_end_io.bio =
2093                                             chained_block->orig_bio_bh_end_io.
2094                                             bio;
2095                                         block->next_in_same_bio = chained_block;
2096                                         bio->bi_private = block;
2097                                 }
2098                         } else if (NULL != bh) {
2099                                 block->is_iodone = 0;
2100                                 block->orig_bio_bh_private = bh->b_private;
2101                                 block->orig_bio_bh_end_io.bh = bh->b_end_io;
2102                                 block->next_in_same_bio = NULL;
2103                                 bh->b_private = block;
2104                                 bh->b_end_io = btrfsic_bh_end_io;
2105                         } else {
2106                                 block->is_iodone = 1;
2107                                 block->orig_bio_bh_private = NULL;
2108                                 block->orig_bio_bh_end_io.bio = NULL;
2109                                 block->next_in_same_bio = NULL;
2110                         }
2111                 }
2112
2113                 block->flush_gen = dev_state->last_flush_gen + 1;
2114                 block->submit_bio_bh_rw = submit_bio_bh_rw;
2115                 if (is_metadata) {
2116                         block->logical_bytenr = bytenr;
2117                         block->is_metadata = 1;
2118                         if (block->is_superblock) {
2119                                 BUG_ON(PAGE_CACHE_SIZE !=
2120                                        BTRFS_SUPER_INFO_SIZE);
2121                                 ret = btrfsic_process_written_superblock(
2122                                                 state,
2123                                                 block,
2124                                                 (struct btrfs_super_block *)
2125                                                 mapped_datav[0]);
2126                                 if (state->print_mask &
2127                                     BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE) {
2128                                         printk(KERN_INFO
2129                                         "[after new superblock is written]:\n");
2130                                         btrfsic_dump_tree_sub(state, block, 0);
2131                                 }
2132                         } else {
2133                                 block->mirror_num = 0;  /* unknown */
2134                                 ret = btrfsic_process_metablock(
2135                                                 state,
2136                                                 block,
2137                                                 &block_ctx,
2138                                                 0, 0);
2139                         }
2140                         if (ret)
2141                                 printk(KERN_INFO
2142                                        "btrfsic: btrfsic_process_metablock"
2143                                        "(root @%llu) failed!\n",
2144                                        (unsigned long long)dev_bytenr);
2145                 } else {
2146                         block->is_metadata = 0;
2147                         block->mirror_num = 0;  /* unknown */
2148                         block->generation = BTRFSIC_GENERATION_UNKNOWN;
2149                         if (!state->include_extent_data
2150                             && list_empty(&block->ref_from_list)) {
2151                                 /*
2152                                  * disk block is overwritten with extent
2153                                  * data (not meta data) and we are configured
2154                                  * to not include extent data: take the
2155                                  * chance and free the block's memory
2156                                  */
2157                                 btrfsic_block_hashtable_remove(block);
2158                                 list_del(&block->all_blocks_node);
2159                                 btrfsic_block_free(block);
2160                         }
2161                 }
2162                 btrfsic_release_block_ctx(&block_ctx);
2163         } else {
2164                 /* block has not been found in hash table */
2165                 u64 bytenr;
2166
2167                 if (!is_metadata) {
2168                         processed_len = state->datablock_size;
2169                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2170                                 printk(KERN_INFO "Written block (%s/%llu/?)"
2171                                        " !found in hash table, D.\n",
2172                                        dev_state->name,
2173                                        (unsigned long long)dev_bytenr);
2174                         if (!state->include_extent_data) {
2175                                 /* ignore that written D block */
2176                                 goto continue_loop;
2177                         }
2178
2179                         /* this is getting ugly for the
2180                          * include_extent_data case... */
2181                         bytenr = 0;     /* unknown */
2182                         block_ctx.start = bytenr;
2183                         block_ctx.len = processed_len;
2184                         block_ctx.mem_to_free = NULL;
2185                         block_ctx.pagev = NULL;
2186                 } else {
2187                         processed_len = state->metablock_size;
2188                         bytenr = le64_to_cpu(((struct btrfs_header *)
2189                                               mapped_datav[0])->bytenr);
2190                         btrfsic_cmp_log_and_dev_bytenr(state, bytenr, dev_state,
2191                                                        dev_bytenr);
2192                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2193                                 printk(KERN_INFO
2194                                        "Written block @%llu (%s/%llu/?)"
2195                                        " !found in hash table, M.\n",
2196                                        (unsigned long long)bytenr,
2197                                        dev_state->name,
2198                                        (unsigned long long)dev_bytenr);
2199
2200                         ret = btrfsic_map_block(state, bytenr, processed_len,
2201                                                 &block_ctx, 0);
2202                         if (ret) {
2203                                 printk(KERN_INFO
2204                                        "btrfsic: btrfsic_map_block(root @%llu)"
2205                                        " failed!\n",
2206                                        (unsigned long long)dev_bytenr);
2207                                 goto continue_loop;
2208                         }
2209                 }
2210                 block_ctx.datav = mapped_datav;
2211                 /* the following is required in case of writes to mirrors,
2212                  * use the same that was used for the lookup */
2213                 block_ctx.dev = dev_state;
2214                 block_ctx.dev_bytenr = dev_bytenr;
2215
2216                 block = btrfsic_block_alloc();
2217                 if (NULL == block) {
2218                         printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2219                         btrfsic_release_block_ctx(&block_ctx);
2220                         goto continue_loop;
2221                 }
2222                 block->dev_state = dev_state;
2223                 block->dev_bytenr = dev_bytenr;
2224                 block->logical_bytenr = bytenr;
2225                 block->is_metadata = is_metadata;
2226                 block->never_written = 0;
2227                 block->iodone_w_error = 0;
2228                 block->mirror_num = 0;  /* unknown */
2229                 block->flush_gen = dev_state->last_flush_gen + 1;
2230                 block->submit_bio_bh_rw = submit_bio_bh_rw;
2231                 if (NULL != bio) {
2232                         block->is_iodone = 0;
2233                         BUG_ON(NULL == bio_is_patched);
2234                         if (!*bio_is_patched) {
2235                                 block->orig_bio_bh_private = bio->bi_private;
2236                                 block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2237                                 block->next_in_same_bio = NULL;
2238                                 bio->bi_private = block;
2239                                 bio->bi_end_io = btrfsic_bio_end_io;
2240                                 *bio_is_patched = 1;
2241                         } else {
2242                                 struct btrfsic_block *chained_block =
2243                                     (struct btrfsic_block *)
2244                                     bio->bi_private;
2245
2246                                 BUG_ON(NULL == chained_block);
2247                                 block->orig_bio_bh_private =
2248                                     chained_block->orig_bio_bh_private;
2249                                 block->orig_bio_bh_end_io.bio =
2250                                     chained_block->orig_bio_bh_end_io.bio;
2251                                 block->next_in_same_bio = chained_block;
2252                                 bio->bi_private = block;
2253                         }
2254                 } else if (NULL != bh) {
2255                         block->is_iodone = 0;
2256                         block->orig_bio_bh_private = bh->b_private;
2257                         block->orig_bio_bh_end_io.bh = bh->b_end_io;
2258                         block->next_in_same_bio = NULL;
2259                         bh->b_private = block;
2260                         bh->b_end_io = btrfsic_bh_end_io;
2261                 } else {
2262                         block->is_iodone = 1;
2263                         block->orig_bio_bh_private = NULL;
2264                         block->orig_bio_bh_end_io.bio = NULL;
2265                         block->next_in_same_bio = NULL;
2266                 }
2267                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2268                         printk(KERN_INFO
2269                                "New written %c-block @%llu (%s/%llu/%d)\n",
2270                                is_metadata ? 'M' : 'D',
2271                                (unsigned long long)block->logical_bytenr,
2272                                block->dev_state->name,
2273                                (unsigned long long)block->dev_bytenr,
2274                                block->mirror_num);
2275                 list_add(&block->all_blocks_node, &state->all_blocks_list);
2276                 btrfsic_block_hashtable_add(block, &state->block_hashtable);
2277
2278                 if (is_metadata) {
2279                         ret = btrfsic_process_metablock(state, block,
2280                                                         &block_ctx, 0, 0);
2281                         if (ret)
2282                                 printk(KERN_INFO
2283                                        "btrfsic: process_metablock(root @%llu)"
2284                                        " failed!\n",
2285                                        (unsigned long long)dev_bytenr);
2286                 }
2287                 btrfsic_release_block_ctx(&block_ctx);
2288         }
2289
2290 continue_loop:
2291         BUG_ON(!processed_len);
2292         dev_bytenr += processed_len;
2293         mapped_datav += processed_len >> PAGE_CACHE_SHIFT;
2294         num_pages -= processed_len >> PAGE_CACHE_SHIFT;
2295         goto again;
2296 }
2297
2298 static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status)
2299 {
2300         struct btrfsic_block *block = (struct btrfsic_block *)bp->bi_private;
2301         int iodone_w_error;
2302
2303         /* mutex is not held! This is not save if IO is not yet completed
2304          * on umount */
2305         iodone_w_error = 0;
2306         if (bio_error_status)
2307                 iodone_w_error = 1;
2308
2309         BUG_ON(NULL == block);
2310         bp->bi_private = block->orig_bio_bh_private;
2311         bp->bi_end_io = block->orig_bio_bh_end_io.bio;
2312
2313         do {
2314                 struct btrfsic_block *next_block;
2315                 struct btrfsic_dev_state *const dev_state = block->dev_state;
2316
2317                 if ((dev_state->state->print_mask &
2318                      BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2319                         printk(KERN_INFO
2320                                "bio_end_io(err=%d) for %c @%llu (%s/%llu/%d)\n",
2321                                bio_error_status,
2322                                btrfsic_get_block_type(dev_state->state, block),
2323                                (unsigned long long)block->logical_bytenr,
2324                                dev_state->name,
2325                                (unsigned long long)block->dev_bytenr,
2326                                block->mirror_num);
2327                 next_block = block->next_in_same_bio;
2328                 block->iodone_w_error = iodone_w_error;
2329                 if (block->submit_bio_bh_rw & REQ_FLUSH) {
2330                         dev_state->last_flush_gen++;
2331                         if ((dev_state->state->print_mask &
2332                              BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2333                                 printk(KERN_INFO
2334                                        "bio_end_io() new %s flush_gen=%llu\n",
2335                                        dev_state->name,
2336                                        (unsigned long long)
2337                                        dev_state->last_flush_gen);
2338                 }
2339                 if (block->submit_bio_bh_rw & REQ_FUA)
2340                         block->flush_gen = 0; /* FUA completed means block is
2341                                                * on disk */
2342                 block->is_iodone = 1; /* for FLUSH, this releases the block */
2343                 block = next_block;
2344         } while (NULL != block);
2345
2346         bp->bi_end_io(bp, bio_error_status);
2347 }
2348
2349 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate)
2350 {
2351         struct btrfsic_block *block = (struct btrfsic_block *)bh->b_private;
2352         int iodone_w_error = !uptodate;
2353         struct btrfsic_dev_state *dev_state;
2354
2355         BUG_ON(NULL == block);
2356         dev_state = block->dev_state;
2357         if ((dev_state->state->print_mask & BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2358                 printk(KERN_INFO
2359                        "bh_end_io(error=%d) for %c @%llu (%s/%llu/%d)\n",
2360                        iodone_w_error,
2361                        btrfsic_get_block_type(dev_state->state, block),
2362                        (unsigned long long)block->logical_bytenr,
2363                        block->dev_state->name,
2364                        (unsigned long long)block->dev_bytenr,
2365                        block->mirror_num);
2366
2367         block->iodone_w_error = iodone_w_error;
2368         if (block->submit_bio_bh_rw & REQ_FLUSH) {
2369                 dev_state->last_flush_gen++;
2370                 if ((dev_state->state->print_mask &
2371                      BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2372                         printk(KERN_INFO
2373                                "bh_end_io() new %s flush_gen=%llu\n",
2374                                dev_state->name,
2375                                (unsigned long long)dev_state->last_flush_gen);
2376         }
2377         if (block->submit_bio_bh_rw & REQ_FUA)
2378                 block->flush_gen = 0; /* FUA completed means block is on disk */
2379
2380         bh->b_private = block->orig_bio_bh_private;
2381         bh->b_end_io = block->orig_bio_bh_end_io.bh;
2382         block->is_iodone = 1; /* for FLUSH, this releases the block */
2383         bh->b_end_io(bh, uptodate);
2384 }
2385
2386 static int btrfsic_process_written_superblock(
2387                 struct btrfsic_state *state,
2388                 struct btrfsic_block *const superblock,
2389                 struct btrfs_super_block *const super_hdr)
2390 {
2391         int pass;
2392
2393         superblock->generation = btrfs_super_generation(super_hdr);
2394         if (!(superblock->generation > state->max_superblock_generation ||
2395               0 == state->max_superblock_generation)) {
2396                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2397                         printk(KERN_INFO
2398                                "btrfsic: superblock @%llu (%s/%llu/%d)"
2399                                " with old gen %llu <= %llu\n",
2400                                (unsigned long long)superblock->logical_bytenr,
2401                                superblock->dev_state->name,
2402                                (unsigned long long)superblock->dev_bytenr,
2403                                superblock->mirror_num,
2404                                (unsigned long long)
2405                                btrfs_super_generation(super_hdr),
2406                                (unsigned long long)
2407                                state->max_superblock_generation);
2408         } else {
2409                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2410                         printk(KERN_INFO
2411                                "btrfsic: got new superblock @%llu (%s/%llu/%d)"
2412                                " with new gen %llu > %llu\n",
2413                                (unsigned long long)superblock->logical_bytenr,
2414                                superblock->dev_state->name,
2415                                (unsigned long long)superblock->dev_bytenr,
2416                                superblock->mirror_num,
2417                                (unsigned long long)
2418                                btrfs_super_generation(super_hdr),
2419                                (unsigned long long)
2420                                state->max_superblock_generation);
2421
2422                 state->max_superblock_generation =
2423                     btrfs_super_generation(super_hdr);
2424                 state->latest_superblock = superblock;
2425         }
2426
2427         for (pass = 0; pass < 3; pass++) {
2428                 int ret;
2429                 u64 next_bytenr;
2430                 struct btrfsic_block *next_block;
2431                 struct btrfsic_block_data_ctx tmp_next_block_ctx;
2432                 struct btrfsic_block_link *l;
2433                 int num_copies;
2434                 int mirror_num;
2435                 const char *additional_string = NULL;
2436                 struct btrfs_disk_key tmp_disk_key;
2437
2438                 tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
2439                 tmp_disk_key.offset = 0;
2440
2441                 switch (pass) {
2442                 case 0:
2443                         tmp_disk_key.objectid =
2444                             cpu_to_le64(BTRFS_ROOT_TREE_OBJECTID);
2445                         additional_string = "root ";
2446                         next_bytenr = btrfs_super_root(super_hdr);
2447                         if (state->print_mask &
2448                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2449                                 printk(KERN_INFO "root@%llu\n",
2450                                        (unsigned long long)next_bytenr);
2451                         break;
2452                 case 1:
2453                         tmp_disk_key.objectid =
2454                             cpu_to_le64(BTRFS_CHUNK_TREE_OBJECTID);
2455                         additional_string = "chunk ";
2456                         next_bytenr = btrfs_super_chunk_root(super_hdr);
2457                         if (state->print_mask &
2458                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2459                                 printk(KERN_INFO "chunk@%llu\n",
2460                                        (unsigned long long)next_bytenr);
2461                         break;
2462                 case 2:
2463                         tmp_disk_key.objectid =
2464                             cpu_to_le64(BTRFS_TREE_LOG_OBJECTID);
2465                         additional_string = "log ";
2466                         next_bytenr = btrfs_super_log_root(super_hdr);
2467                         if (0 == next_bytenr)
2468                                 continue;
2469                         if (state->print_mask &
2470                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2471                                 printk(KERN_INFO "log@%llu\n",
2472                                        (unsigned long long)next_bytenr);
2473                         break;
2474                 }
2475
2476                 num_copies =
2477                     btrfs_num_copies(state->root->fs_info,
2478                                      next_bytenr, BTRFS_SUPER_INFO_SIZE);
2479                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
2480                         printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
2481                                (unsigned long long)next_bytenr, num_copies);
2482                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2483                         int was_created;
2484
2485                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2486                                 printk(KERN_INFO
2487                                        "btrfsic_process_written_superblock("
2488                                        "mirror_num=%d)\n", mirror_num);
2489                         ret = btrfsic_map_block(state, next_bytenr,
2490                                                 BTRFS_SUPER_INFO_SIZE,
2491                                                 &tmp_next_block_ctx,
2492                                                 mirror_num);
2493                         if (ret) {
2494                                 printk(KERN_INFO
2495                                        "btrfsic: btrfsic_map_block(@%llu,"
2496                                        " mirror=%d) failed!\n",
2497                                        (unsigned long long)next_bytenr,
2498                                        mirror_num);
2499                                 return -1;
2500                         }
2501
2502                         next_block = btrfsic_block_lookup_or_add(
2503                                         state,
2504                                         &tmp_next_block_ctx,
2505                                         additional_string,
2506                                         1, 0, 1,
2507                                         mirror_num,
2508                                         &was_created);
2509                         if (NULL == next_block) {
2510                                 printk(KERN_INFO
2511                                        "btrfsic: error, kmalloc failed!\n");
2512                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
2513                                 return -1;
2514                         }
2515
2516                         next_block->disk_key = tmp_disk_key;
2517                         if (was_created)
2518                                 next_block->generation =
2519                                     BTRFSIC_GENERATION_UNKNOWN;
2520                         l = btrfsic_block_link_lookup_or_add(
2521                                         state,
2522                                         &tmp_next_block_ctx,
2523                                         next_block,
2524                                         superblock,
2525                                         BTRFSIC_GENERATION_UNKNOWN);
2526                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
2527                         if (NULL == l)
2528                                 return -1;
2529                 }
2530         }
2531
2532         if (-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)) {
2533                 WARN_ON(1);
2534                 btrfsic_dump_tree(state);
2535         }
2536
2537         return 0;
2538 }
2539
2540 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
2541                                         struct btrfsic_block *const block,
2542                                         int recursion_level)
2543 {
2544         struct list_head *elem_ref_to;
2545         int ret = 0;
2546
2547         if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2548                 /*
2549                  * Note that this situation can happen and does not
2550                  * indicate an error in regular cases. It happens
2551                  * when disk blocks are freed and later reused.
2552                  * The check-integrity module is not aware of any
2553                  * block free operations, it just recognizes block
2554                  * write operations. Therefore it keeps the linkage
2555                  * information for a block until a block is
2556                  * rewritten. This can temporarily cause incorrect
2557                  * and even circular linkage informations. This
2558                  * causes no harm unless such blocks are referenced
2559                  * by the most recent super block.
2560                  */
2561                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2562                         printk(KERN_INFO
2563                                "btrfsic: abort cyclic linkage (case 1).\n");
2564
2565                 return ret;
2566         }
2567
2568         /*
2569          * This algorithm is recursive because the amount of used stack
2570          * space is very small and the max recursion depth is limited.
2571          */
2572         list_for_each(elem_ref_to, &block->ref_to_list) {
2573                 const struct btrfsic_block_link *const l =
2574                     list_entry(elem_ref_to, struct btrfsic_block_link,
2575                                node_ref_to);
2576
2577                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2578                         printk(KERN_INFO
2579                                "rl=%d, %c @%llu (%s/%llu/%d)"
2580                                " %u* refers to %c @%llu (%s/%llu/%d)\n",
2581                                recursion_level,
2582                                btrfsic_get_block_type(state, block),
2583                                (unsigned long long)block->logical_bytenr,
2584                                block->dev_state->name,
2585                                (unsigned long long)block->dev_bytenr,
2586                                block->mirror_num,
2587                                l->ref_cnt,
2588                                btrfsic_get_block_type(state, l->block_ref_to),
2589                                (unsigned long long)
2590                                l->block_ref_to->logical_bytenr,
2591                                l->block_ref_to->dev_state->name,
2592                                (unsigned long long)l->block_ref_to->dev_bytenr,
2593                                l->block_ref_to->mirror_num);
2594                 if (l->block_ref_to->never_written) {
2595                         printk(KERN_INFO "btrfs: attempt to write superblock"
2596                                " which references block %c @%llu (%s/%llu/%d)"
2597                                " which is never written!\n",
2598                                btrfsic_get_block_type(state, l->block_ref_to),
2599                                (unsigned long long)
2600                                l->block_ref_to->logical_bytenr,
2601                                l->block_ref_to->dev_state->name,
2602                                (unsigned long long)l->block_ref_to->dev_bytenr,
2603                                l->block_ref_to->mirror_num);
2604                         ret = -1;
2605                 } else if (!l->block_ref_to->is_iodone) {
2606                         printk(KERN_INFO "btrfs: attempt to write superblock"
2607                                " which references block %c @%llu (%s/%llu/%d)"
2608                                " which is not yet iodone!\n",
2609                                btrfsic_get_block_type(state, l->block_ref_to),
2610                                (unsigned long long)
2611                                l->block_ref_to->logical_bytenr,
2612                                l->block_ref_to->dev_state->name,
2613                                (unsigned long long)l->block_ref_to->dev_bytenr,
2614                                l->block_ref_to->mirror_num);
2615                         ret = -1;
2616                 } else if (l->block_ref_to->iodone_w_error) {
2617                         printk(KERN_INFO "btrfs: attempt to write superblock"
2618                                " which references block %c @%llu (%s/%llu/%d)"
2619                                " which has write error!\n",
2620                                btrfsic_get_block_type(state, l->block_ref_to),
2621                                (unsigned long long)
2622                                l->block_ref_to->logical_bytenr,
2623                                l->block_ref_to->dev_state->name,
2624                                (unsigned long long)l->block_ref_to->dev_bytenr,
2625                                l->block_ref_to->mirror_num);
2626                         ret = -1;
2627                 } else if (l->parent_generation !=
2628                            l->block_ref_to->generation &&
2629                            BTRFSIC_GENERATION_UNKNOWN !=
2630                            l->parent_generation &&
2631                            BTRFSIC_GENERATION_UNKNOWN !=
2632                            l->block_ref_to->generation) {
2633                         printk(KERN_INFO "btrfs: attempt to write superblock"
2634                                " which references block %c @%llu (%s/%llu/%d)"
2635                                " with generation %llu !="
2636                                " parent generation %llu!\n",
2637                                btrfsic_get_block_type(state, l->block_ref_to),
2638                                (unsigned long long)
2639                                l->block_ref_to->logical_bytenr,
2640                                l->block_ref_to->dev_state->name,
2641                                (unsigned long long)l->block_ref_to->dev_bytenr,
2642                                l->block_ref_to->mirror_num,
2643                                (unsigned long long)l->block_ref_to->generation,
2644                                (unsigned long long)l->parent_generation);
2645                         ret = -1;
2646                 } else if (l->block_ref_to->flush_gen >
2647                            l->block_ref_to->dev_state->last_flush_gen) {
2648                         printk(KERN_INFO "btrfs: attempt to write superblock"
2649                                " which references block %c @%llu (%s/%llu/%d)"
2650                                " which is not flushed out of disk's write cache"
2651                                " (block flush_gen=%llu,"
2652                                " dev->flush_gen=%llu)!\n",
2653                                btrfsic_get_block_type(state, l->block_ref_to),
2654                                (unsigned long long)
2655                                l->block_ref_to->logical_bytenr,
2656                                l->block_ref_to->dev_state->name,
2657                                (unsigned long long)l->block_ref_to->dev_bytenr,
2658                                l->block_ref_to->mirror_num,
2659                                (unsigned long long)block->flush_gen,
2660                                (unsigned long long)
2661                                l->block_ref_to->dev_state->last_flush_gen);
2662                         ret = -1;
2663                 } else if (-1 == btrfsic_check_all_ref_blocks(state,
2664                                                               l->block_ref_to,
2665                                                               recursion_level +
2666                                                               1)) {
2667                         ret = -1;
2668                 }
2669         }
2670
2671         return ret;
2672 }
2673
2674 static int btrfsic_is_block_ref_by_superblock(
2675                 const struct btrfsic_state *state,
2676                 const struct btrfsic_block *block,
2677                 int recursion_level)
2678 {
2679         struct list_head *elem_ref_from;
2680
2681         if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2682                 /* refer to comment at "abort cyclic linkage (case 1)" */
2683                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2684                         printk(KERN_INFO
2685                                "btrfsic: abort cyclic linkage (case 2).\n");
2686
2687                 return 0;
2688         }
2689
2690         /*
2691          * This algorithm is recursive because the amount of used stack space
2692          * is very small and the max recursion depth is limited.
2693          */
2694         list_for_each(elem_ref_from, &block->ref_from_list) {
2695                 const struct btrfsic_block_link *const l =
2696                     list_entry(elem_ref_from, struct btrfsic_block_link,
2697                                node_ref_from);
2698
2699                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2700                         printk(KERN_INFO
2701                                "rl=%d, %c @%llu (%s/%llu/%d)"
2702                                " is ref %u* from %c @%llu (%s/%llu/%d)\n",
2703                                recursion_level,
2704                                btrfsic_get_block_type(state, block),
2705                                (unsigned long long)block->logical_bytenr,
2706                                block->dev_state->name,
2707                                (unsigned long long)block->dev_bytenr,
2708                                block->mirror_num,
2709                                l->ref_cnt,
2710                                btrfsic_get_block_type(state, l->block_ref_from),
2711                                (unsigned long long)
2712                                l->block_ref_from->logical_bytenr,
2713                                l->block_ref_from->dev_state->name,
2714                                (unsigned long long)
2715                                l->block_ref_from->dev_bytenr,
2716                                l->block_ref_from->mirror_num);
2717                 if (l->block_ref_from->is_superblock &&
2718                     state->latest_superblock->dev_bytenr ==
2719                     l->block_ref_from->dev_bytenr &&
2720                     state->latest_superblock->dev_state->bdev ==
2721                     l->block_ref_from->dev_state->bdev)
2722                         return 1;
2723                 else if (btrfsic_is_block_ref_by_superblock(state,
2724                                                             l->block_ref_from,
2725                                                             recursion_level +
2726                                                             1))
2727                         return 1;
2728         }
2729
2730         return 0;
2731 }
2732
2733 static void btrfsic_print_add_link(const struct btrfsic_state *state,
2734                                    const struct btrfsic_block_link *l)
2735 {
2736         printk(KERN_INFO
2737                "Add %u* link from %c @%llu (%s/%llu/%d)"
2738                " to %c @%llu (%s/%llu/%d).\n",
2739                l->ref_cnt,
2740                btrfsic_get_block_type(state, l->block_ref_from),
2741                (unsigned long long)l->block_ref_from->logical_bytenr,
2742                l->block_ref_from->dev_state->name,
2743                (unsigned long long)l->block_ref_from->dev_bytenr,
2744                l->block_ref_from->mirror_num,
2745                btrfsic_get_block_type(state, l->block_ref_to),
2746                (unsigned long long)l->block_ref_to->logical_bytenr,
2747                l->block_ref_to->dev_state->name,
2748                (unsigned long long)l->block_ref_to->dev_bytenr,
2749                l->block_ref_to->mirror_num);
2750 }
2751
2752 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
2753                                    const struct btrfsic_block_link *l)
2754 {
2755         printk(KERN_INFO
2756                "Rem %u* link from %c @%llu (%s/%llu/%d)"
2757                " to %c @%llu (%s/%llu/%d).\n",
2758                l->ref_cnt,
2759                btrfsic_get_block_type(state, l->block_ref_from),
2760                (unsigned long long)l->block_ref_from->logical_bytenr,
2761                l->block_ref_from->dev_state->name,
2762                (unsigned long long)l->block_ref_from->dev_bytenr,
2763                l->block_ref_from->mirror_num,
2764                btrfsic_get_block_type(state, l->block_ref_to),
2765                (unsigned long long)l->block_ref_to->logical_bytenr,
2766                l->block_ref_to->dev_state->name,
2767                (unsigned long long)l->block_ref_to->dev_bytenr,
2768                l->block_ref_to->mirror_num);
2769 }
2770
2771 static char btrfsic_get_block_type(const struct btrfsic_state *state,
2772                                    const struct btrfsic_block *block)
2773 {
2774         if (block->is_superblock &&
2775             state->latest_superblock->dev_bytenr == block->dev_bytenr &&
2776             state->latest_superblock->dev_state->bdev == block->dev_state->bdev)
2777                 return 'S';
2778         else if (block->is_superblock)
2779                 return 's';
2780         else if (block->is_metadata)
2781                 return 'M';
2782         else
2783                 return 'D';
2784 }
2785
2786 static void btrfsic_dump_tree(const struct btrfsic_state *state)
2787 {
2788         btrfsic_dump_tree_sub(state, state->latest_superblock, 0);
2789 }
2790
2791 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
2792                                   const struct btrfsic_block *block,
2793                                   int indent_level)
2794 {
2795         struct list_head *elem_ref_to;
2796         int indent_add;
2797         static char buf[80];
2798         int cursor_position;
2799
2800         /*
2801          * Should better fill an on-stack buffer with a complete line and
2802          * dump it at once when it is time to print a newline character.
2803          */
2804
2805         /*
2806          * This algorithm is recursive because the amount of used stack space
2807          * is very small and the max recursion depth is limited.
2808          */
2809         indent_add = sprintf(buf, "%c-%llu(%s/%llu/%d)",
2810                              btrfsic_get_block_type(state, block),
2811                              (unsigned long long)block->logical_bytenr,
2812                              block->dev_state->name,
2813                              (unsigned long long)block->dev_bytenr,
2814                              block->mirror_num);
2815         if (indent_level + indent_add > BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2816                 printk("[...]\n");
2817                 return;
2818         }
2819         printk(buf);
2820         indent_level += indent_add;
2821         if (list_empty(&block->ref_to_list)) {
2822                 printk("\n");
2823                 return;
2824         }
2825         if (block->mirror_num > 1 &&
2826             !(state->print_mask & BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS)) {
2827                 printk(" [...]\n");
2828                 return;
2829         }
2830
2831         cursor_position = indent_level;
2832         list_for_each(elem_ref_to, &block->ref_to_list) {
2833                 const struct btrfsic_block_link *const l =
2834                     list_entry(elem_ref_to, struct btrfsic_block_link,
2835                                node_ref_to);
2836
2837                 while (cursor_position < indent_level) {
2838                         printk(" ");
2839                         cursor_position++;
2840                 }
2841                 if (l->ref_cnt > 1)
2842                         indent_add = sprintf(buf, " %d*--> ", l->ref_cnt);
2843                 else
2844                         indent_add = sprintf(buf, " --> ");
2845                 if (indent_level + indent_add >
2846                     BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2847                         printk("[...]\n");
2848                         cursor_position = 0;
2849                         continue;
2850                 }
2851
2852                 printk(buf);
2853
2854                 btrfsic_dump_tree_sub(state, l->block_ref_to,
2855                                       indent_level + indent_add);
2856                 cursor_position = 0;
2857         }
2858 }
2859
2860 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
2861                 struct btrfsic_state *state,
2862                 struct btrfsic_block_data_ctx *next_block_ctx,
2863                 struct btrfsic_block *next_block,
2864                 struct btrfsic_block *from_block,
2865                 u64 parent_generation)
2866 {
2867         struct btrfsic_block_link *l;
2868
2869         l = btrfsic_block_link_hashtable_lookup(next_block_ctx->dev->bdev,
2870                                                 next_block_ctx->dev_bytenr,
2871                                                 from_block->dev_state->bdev,
2872                                                 from_block->dev_bytenr,
2873                                                 &state->block_link_hashtable);
2874         if (NULL == l) {
2875                 l = btrfsic_block_link_alloc();
2876                 if (NULL == l) {
2877                         printk(KERN_INFO
2878                                "btrfsic: error, kmalloc" " failed!\n");
2879                         return NULL;
2880                 }
2881
2882                 l->block_ref_to = next_block;
2883                 l->block_ref_from = from_block;
2884                 l->ref_cnt = 1;
2885                 l->parent_generation = parent_generation;
2886
2887                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2888                         btrfsic_print_add_link(state, l);
2889
2890                 list_add(&l->node_ref_to, &from_block->ref_to_list);
2891                 list_add(&l->node_ref_from, &next_block->ref_from_list);
2892
2893                 btrfsic_block_link_hashtable_add(l,
2894                                                  &state->block_link_hashtable);
2895         } else {
2896                 l->ref_cnt++;
2897                 l->parent_generation = parent_generation;
2898                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2899                         btrfsic_print_add_link(state, l);
2900         }
2901
2902         return l;
2903 }
2904
2905 static struct btrfsic_block *btrfsic_block_lookup_or_add(
2906                 struct btrfsic_state *state,
2907                 struct btrfsic_block_data_ctx *block_ctx,
2908                 const char *additional_string,
2909                 int is_metadata,
2910                 int is_iodone,
2911                 int never_written,
2912                 int mirror_num,
2913                 int *was_created)
2914 {
2915         struct btrfsic_block *block;
2916
2917         block = btrfsic_block_hashtable_lookup(block_ctx->dev->bdev,
2918                                                block_ctx->dev_bytenr,
2919                                                &state->block_hashtable);
2920         if (NULL == block) {
2921                 struct btrfsic_dev_state *dev_state;
2922
2923                 block = btrfsic_block_alloc();
2924                 if (NULL == block) {
2925                         printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2926                         return NULL;
2927                 }
2928                 dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev);
2929                 if (NULL == dev_state) {
2930                         printk(KERN_INFO
2931                                "btrfsic: error, lookup dev_state failed!\n");
2932                         btrfsic_block_free(block);
2933                         return NULL;
2934                 }
2935                 block->dev_state = dev_state;
2936                 block->dev_bytenr = block_ctx->dev_bytenr;
2937                 block->logical_bytenr = block_ctx->start;
2938                 block->is_metadata = is_metadata;
2939                 block->is_iodone = is_iodone;
2940                 block->never_written = never_written;
2941                 block->mirror_num = mirror_num;
2942                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2943                         printk(KERN_INFO
2944                                "New %s%c-block @%llu (%s/%llu/%d)\n",
2945                                additional_string,
2946                                btrfsic_get_block_type(state, block),
2947                                (unsigned long long)block->logical_bytenr,
2948                                dev_state->name,
2949                                (unsigned long long)block->dev_bytenr,
2950                                mirror_num);
2951                 list_add(&block->all_blocks_node, &state->all_blocks_list);
2952                 btrfsic_block_hashtable_add(block, &state->block_hashtable);
2953                 if (NULL != was_created)
2954                         *was_created = 1;
2955         } else {
2956                 if (NULL != was_created)
2957                         *was_created = 0;
2958         }
2959
2960         return block;
2961 }
2962
2963 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
2964                                            u64 bytenr,
2965                                            struct btrfsic_dev_state *dev_state,
2966                                            u64 dev_bytenr)
2967 {
2968         int num_copies;
2969         int mirror_num;
2970         int ret;
2971         struct btrfsic_block_data_ctx block_ctx;
2972         int match = 0;
2973
2974         num_copies = btrfs_num_copies(state->root->fs_info,
2975                                       bytenr, state->metablock_size);
2976
2977         for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2978                 ret = btrfsic_map_block(state, bytenr, state->metablock_size,
2979                                         &block_ctx, mirror_num);
2980                 if (ret) {
2981                         printk(KERN_INFO "btrfsic:"
2982                                " btrfsic_map_block(logical @%llu,"
2983                                " mirror %d) failed!\n",
2984                                (unsigned long long)bytenr, mirror_num);
2985                         continue;
2986                 }
2987
2988                 if (dev_state->bdev == block_ctx.dev->bdev &&
2989                     dev_bytenr == block_ctx.dev_bytenr) {
2990                         match++;
2991                         btrfsic_release_block_ctx(&block_ctx);
2992                         break;
2993                 }
2994                 btrfsic_release_block_ctx(&block_ctx);
2995         }
2996
2997         if (!match) {
2998                 printk(KERN_INFO "btrfs: attempt to write M-block which contains logical bytenr that doesn't map to dev+physical bytenr of submit_bio,"
2999                        " buffer->log_bytenr=%llu, submit_bio(bdev=%s,"
3000                        " phys_bytenr=%llu)!\n",
3001                        (unsigned long long)bytenr, dev_state->name,
3002                        (unsigned long long)dev_bytenr);
3003                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
3004                         ret = btrfsic_map_block(state, bytenr,
3005                                                 state->metablock_size,
3006                                                 &block_ctx, mirror_num);
3007                         if (ret)
3008                                 continue;
3009
3010                         printk(KERN_INFO "Read logical bytenr @%llu maps to"
3011                                " (%s/%llu/%d)\n",
3012                                (unsigned long long)bytenr,
3013                                block_ctx.dev->name,
3014                                (unsigned long long)block_ctx.dev_bytenr,
3015                                mirror_num);
3016                 }
3017                 WARN_ON(1);
3018         }
3019 }
3020
3021 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
3022                 struct block_device *bdev)
3023 {
3024         struct btrfsic_dev_state *ds;
3025
3026         ds = btrfsic_dev_state_hashtable_lookup(bdev,
3027                                                 &btrfsic_dev_state_hashtable);
3028         return ds;
3029 }
3030
3031 int btrfsic_submit_bh(int rw, struct buffer_head *bh)
3032 {
3033         struct btrfsic_dev_state *dev_state;
3034
3035         if (!btrfsic_is_initialized)
3036                 return submit_bh(rw, bh);
3037
3038         mutex_lock(&btrfsic_mutex);
3039         /* since btrfsic_submit_bh() might also be called before
3040          * btrfsic_mount(), this might return NULL */
3041         dev_state = btrfsic_dev_state_lookup(bh->b_bdev);
3042
3043         /* Only called to write the superblock (incl. FLUSH/FUA) */
3044         if (NULL != dev_state &&
3045             (rw & WRITE) && bh->b_size > 0) {
3046                 u64 dev_bytenr;
3047
3048                 dev_bytenr = 4096 * bh->b_blocknr;
3049                 if (dev_state->state->print_mask &
3050                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3051                         printk(KERN_INFO
3052                                "submit_bh(rw=0x%x, blocknr=%lu (bytenr %llu),"
3053                                " size=%lu, data=%p, bdev=%p)\n",
3054                                rw, (unsigned long)bh->b_blocknr,
3055                                (unsigned long long)dev_bytenr,
3056                                (unsigned long)bh->b_size, bh->b_data,
3057                                bh->b_bdev);
3058                 btrfsic_process_written_block(dev_state, dev_bytenr,
3059                                               &bh->b_data, 1, NULL,
3060                                               NULL, bh, rw);
3061         } else if (NULL != dev_state && (rw & REQ_FLUSH)) {
3062                 if (dev_state->state->print_mask &
3063                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3064                         printk(KERN_INFO
3065                                "submit_bh(rw=0x%x FLUSH, bdev=%p)\n",
3066                                rw, bh->b_bdev);
3067                 if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
3068                         if ((dev_state->state->print_mask &
3069                              (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3070                               BTRFSIC_PRINT_MASK_VERBOSE)))
3071                                 printk(KERN_INFO
3072                                        "btrfsic_submit_bh(%s) with FLUSH"
3073                                        " but dummy block already in use"
3074                                        " (ignored)!\n",
3075                                        dev_state->name);
3076                 } else {
3077                         struct btrfsic_block *const block =
3078                                 &dev_state->dummy_block_for_bio_bh_flush;
3079
3080                         block->is_iodone = 0;
3081                         block->never_written = 0;
3082                         block->iodone_w_error = 0;
3083                         block->flush_gen = dev_state->last_flush_gen + 1;
3084                         block->submit_bio_bh_rw = rw;
3085                         block->orig_bio_bh_private = bh->b_private;
3086                         block->orig_bio_bh_end_io.bh = bh->b_end_io;
3087                         block->next_in_same_bio = NULL;
3088                         bh->b_private = block;
3089                         bh->b_end_io = btrfsic_bh_end_io;
3090                 }
3091         }
3092         mutex_unlock(&btrfsic_mutex);
3093         return submit_bh(rw, bh);
3094 }
3095
3096 void btrfsic_submit_bio(int rw, struct bio *bio)
3097 {
3098         struct btrfsic_dev_state *dev_state;
3099
3100         if (!btrfsic_is_initialized) {
3101                 submit_bio(rw, bio);
3102                 return;
3103         }
3104
3105         mutex_lock(&btrfsic_mutex);
3106         /* since btrfsic_submit_bio() is also called before
3107          * btrfsic_mount(), this might return NULL */
3108         dev_state = btrfsic_dev_state_lookup(bio->bi_bdev);
3109         if (NULL != dev_state &&
3110             (rw & WRITE) && NULL != bio->bi_io_vec) {
3111                 unsigned int i;
3112                 u64 dev_bytenr;
3113                 int bio_is_patched;
3114                 char **mapped_datav;
3115
3116                 dev_bytenr = 512 * bio->bi_sector;
3117                 bio_is_patched = 0;
3118                 if (dev_state->state->print_mask &
3119                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3120                         printk(KERN_INFO
3121                                "submit_bio(rw=0x%x, bi_vcnt=%u,"
3122                                " bi_sector=%lu (bytenr %llu), bi_bdev=%p)\n",
3123                                rw, bio->bi_vcnt, (unsigned long)bio->bi_sector,
3124                                (unsigned long long)dev_bytenr,
3125                                bio->bi_bdev);
3126
3127                 mapped_datav = kmalloc(sizeof(*mapped_datav) * bio->bi_vcnt,
3128                                        GFP_NOFS);
3129                 if (!mapped_datav)
3130                         goto leave;
3131                 for (i = 0; i < bio->bi_vcnt; i++) {
3132                         BUG_ON(bio->bi_io_vec[i].bv_len != PAGE_CACHE_SIZE);
3133                         mapped_datav[i] = kmap(bio->bi_io_vec[i].bv_page);
3134                         if (!mapped_datav[i]) {
3135                                 while (i > 0) {
3136                                         i--;
3137                                         kunmap(bio->bi_io_vec[i].bv_page);
3138                                 }
3139                                 kfree(mapped_datav);
3140                                 goto leave;
3141                         }
3142                         if ((BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3143                              BTRFSIC_PRINT_MASK_VERBOSE) ==
3144                             (dev_state->state->print_mask &
3145                              (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3146                               BTRFSIC_PRINT_MASK_VERBOSE)))
3147                                 printk(KERN_INFO
3148                                        "#%u: page=%p, len=%u, offset=%u\n",
3149                                        i, bio->bi_io_vec[i].bv_page,
3150                                        bio->bi_io_vec[i].bv_len,
3151                                        bio->bi_io_vec[i].bv_offset);
3152                 }
3153                 btrfsic_process_written_block(dev_state, dev_bytenr,
3154                                               mapped_datav, bio->bi_vcnt,
3155                                               bio, &bio_is_patched,
3156                                               NULL, rw);
3157                 while (i > 0) {
3158                         i--;
3159                         kunmap(bio->bi_io_vec[i].bv_page);
3160                 }
3161                 kfree(mapped_datav);
3162         } else if (NULL != dev_state && (rw & REQ_FLUSH)) {
3163                 if (dev_state->state->print_mask &
3164                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3165                         printk(KERN_INFO
3166                                "submit_bio(rw=0x%x FLUSH, bdev=%p)\n",
3167                                rw, bio->bi_bdev);
3168                 if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
3169                         if ((dev_state->state->print_mask &
3170                              (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3171                               BTRFSIC_PRINT_MASK_VERBOSE)))
3172                                 printk(KERN_INFO
3173                                        "btrfsic_submit_bio(%s) with FLUSH"
3174                                        " but dummy block already in use"
3175                                        " (ignored)!\n",
3176                                        dev_state->name);
3177                 } else {
3178                         struct btrfsic_block *const block =
3179                                 &dev_state->dummy_block_for_bio_bh_flush;
3180
3181                         block->is_iodone = 0;
3182                         block->never_written = 0;
3183                         block->iodone_w_error = 0;
3184                         block->flush_gen = dev_state->last_flush_gen + 1;
3185                         block->submit_bio_bh_rw = rw;
3186                         block->orig_bio_bh_private = bio->bi_private;
3187                         block->orig_bio_bh_end_io.bio = bio->bi_end_io;
3188                         block->next_in_same_bio = NULL;
3189                         bio->bi_private = block;
3190                         bio->bi_end_io = btrfsic_bio_end_io;
3191                 }
3192         }
3193 leave:
3194         mutex_unlock(&btrfsic_mutex);
3195
3196         submit_bio(rw, bio);
3197 }
3198
3199 int btrfsic_mount(struct btrfs_root *root,
3200                   struct btrfs_fs_devices *fs_devices,
3201                   int including_extent_data, u32 print_mask)
3202 {
3203         int ret;
3204         struct btrfsic_state *state;
3205         struct list_head *dev_head = &fs_devices->devices;
3206         struct btrfs_device *device;
3207
3208         if (root->nodesize != root->leafsize) {
3209                 printk(KERN_INFO
3210                        "btrfsic: cannot handle nodesize %d != leafsize %d!\n",
3211                        root->nodesize, root->leafsize);
3212                 return -1;
3213         }
3214         if (root->nodesize & ((u64)PAGE_CACHE_SIZE - 1)) {
3215                 printk(KERN_INFO
3216                        "btrfsic: cannot handle nodesize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3217                        root->nodesize, (unsigned long)PAGE_CACHE_SIZE);
3218                 return -1;
3219         }
3220         if (root->leafsize & ((u64)PAGE_CACHE_SIZE - 1)) {
3221                 printk(KERN_INFO
3222                        "btrfsic: cannot handle leafsize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3223                        root->leafsize, (unsigned long)PAGE_CACHE_SIZE);
3224                 return -1;
3225         }
3226         if (root->sectorsize & ((u64)PAGE_CACHE_SIZE - 1)) {
3227                 printk(KERN_INFO
3228                        "btrfsic: cannot handle sectorsize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3229                        root->sectorsize, (unsigned long)PAGE_CACHE_SIZE);
3230                 return -1;
3231         }
3232         state = kzalloc(sizeof(*state), GFP_NOFS);
3233         if (NULL == state) {
3234                 printk(KERN_INFO "btrfs check-integrity: kmalloc() failed!\n");
3235                 return -1;
3236         }
3237
3238         if (!btrfsic_is_initialized) {
3239                 mutex_init(&btrfsic_mutex);
3240                 btrfsic_dev_state_hashtable_init(&btrfsic_dev_state_hashtable);
3241                 btrfsic_is_initialized = 1;
3242         }
3243         mutex_lock(&btrfsic_mutex);
3244         state->root = root;
3245         state->print_mask = print_mask;
3246         state->include_extent_data = including_extent_data;
3247         state->csum_size = 0;
3248         state->metablock_size = root->nodesize;
3249         state->datablock_size = root->sectorsize;
3250         INIT_LIST_HEAD(&state->all_blocks_list);
3251         btrfsic_block_hashtable_init(&state->block_hashtable);
3252         btrfsic_block_link_hashtable_init(&state->block_link_hashtable);
3253         state->max_superblock_generation = 0;
3254         state->latest_superblock = NULL;
3255
3256         list_for_each_entry(device, dev_head, dev_list) {
3257                 struct btrfsic_dev_state *ds;
3258                 char *p;
3259
3260                 if (!device->bdev || !device->name)
3261                         continue;
3262
3263                 ds = btrfsic_dev_state_alloc();
3264                 if (NULL == ds) {
3265                         printk(KERN_INFO
3266                                "btrfs check-integrity: kmalloc() failed!\n");
3267                         mutex_unlock(&btrfsic_mutex);
3268                         return -1;
3269                 }
3270                 ds->bdev = device->bdev;
3271                 ds->state = state;
3272                 bdevname(ds->bdev, ds->name);
3273                 ds->name[BDEVNAME_SIZE - 1] = '\0';
3274                 for (p = ds->name; *p != '\0'; p++);
3275                 while (p > ds->name && *p != '/')
3276                         p--;
3277                 if (*p == '/')
3278                         p++;
3279                 strlcpy(ds->name, p, sizeof(ds->name));
3280                 btrfsic_dev_state_hashtable_add(ds,
3281                                                 &btrfsic_dev_state_hashtable);
3282         }
3283
3284         ret = btrfsic_process_superblock(state, fs_devices);
3285         if (0 != ret) {
3286                 mutex_unlock(&btrfsic_mutex);
3287                 btrfsic_unmount(root, fs_devices);
3288                 return ret;
3289         }
3290
3291         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_DATABASE)
3292                 btrfsic_dump_database(state);
3293         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_TREE)
3294                 btrfsic_dump_tree(state);
3295
3296         mutex_unlock(&btrfsic_mutex);
3297         return 0;
3298 }
3299
3300 void btrfsic_unmount(struct btrfs_root *root,
3301                      struct btrfs_fs_devices *fs_devices)
3302 {
3303         struct list_head *elem_all;
3304         struct list_head *tmp_all;
3305         struct btrfsic_state *state;
3306         struct list_head *dev_head = &fs_devices->devices;
3307         struct btrfs_device *device;
3308
3309         if (!btrfsic_is_initialized)
3310                 return;
3311
3312         mutex_lock(&btrfsic_mutex);
3313
3314         state = NULL;
3315         list_for_each_entry(device, dev_head, dev_list) {
3316                 struct btrfsic_dev_state *ds;
3317
3318                 if (!device->bdev || !device->name)
3319                         continue;
3320
3321                 ds = btrfsic_dev_state_hashtable_lookup(
3322                                 device->bdev,
3323                                 &btrfsic_dev_state_hashtable);
3324                 if (NULL != ds) {
3325                         state = ds->state;
3326                         btrfsic_dev_state_hashtable_remove(ds);
3327                         btrfsic_dev_state_free(ds);
3328                 }
3329         }
3330
3331         if (NULL == state) {
3332                 printk(KERN_INFO
3333                        "btrfsic: error, cannot find state information"
3334                        " on umount!\n");
3335                 mutex_unlock(&btrfsic_mutex);
3336                 return;
3337         }
3338
3339         /*
3340          * Don't care about keeping the lists' state up to date,
3341          * just free all memory that was allocated dynamically.
3342          * Free the blocks and the block_links.
3343          */
3344         list_for_each_safe(elem_all, tmp_all, &state->all_blocks_list) {
3345                 struct btrfsic_block *const b_all =
3346                     list_entry(elem_all, struct btrfsic_block,
3347                                all_blocks_node);
3348                 struct list_head *elem_ref_to;
3349                 struct list_head *tmp_ref_to;
3350
3351                 list_for_each_safe(elem_ref_to, tmp_ref_to,
3352                                    &b_all->ref_to_list) {
3353                         struct btrfsic_block_link *const l =
3354                             list_entry(elem_ref_to,
3355                                        struct btrfsic_block_link,
3356                                        node_ref_to);
3357
3358                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
3359                                 btrfsic_print_rem_link(state, l);
3360
3361                         l->ref_cnt--;
3362                         if (0 == l->ref_cnt)
3363                                 btrfsic_block_link_free(l);
3364                 }
3365
3366                 if (b_all->is_iodone || b_all->never_written)
3367                         btrfsic_block_free(b_all);
3368                 else
3369                         printk(KERN_INFO "btrfs: attempt to free %c-block"
3370                                " @%llu (%s/%llu/%d) on umount which is"
3371                                " not yet iodone!\n",
3372                                btrfsic_get_block_type(state, b_all),
3373                                (unsigned long long)b_all->logical_bytenr,
3374                                b_all->dev_state->name,
3375                                (unsigned long long)b_all->dev_bytenr,
3376                                b_all->mirror_num);
3377         }
3378
3379         mutex_unlock(&btrfsic_mutex);
3380
3381         kfree(state);
3382 }