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