fs/btrfs/check-integrity.c

   1 /*
   2  * Copyright (C) STRATO AG 2011.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 /*
  20  * This module can be used to catch cases when the btrfs kernel
  21  * code executes write requests to the disk that bring the file
  22  * system in an inconsistent state. In such a state, a power-loss
  23  * or kernel panic event would cause that the data on disk is
  24  * lost or at least damaged.
  25  *
  26  * Code is added that examines all block write requests during
  27  * runtime (including writes of the super block). Three rules
  28  * are verified and an error is printed on violation of the
  29  * rules:
  30  * 1. It is not allowed to write a disk block which is
  31  *    currently referenced by the super block (either directly
  32  *    or indirectly).
  33  * 2. When a super block is written, it is verified that all
  34  *    referenced (directly or indirectly) blocks fulfill the
  35  *    following requirements:
  36  *    2a. All referenced blocks have either been present when
  37  *        the file system was mounted, (i.e., they have been
  38  *        referenced by the super block) or they have been
  39  *        written since then and the write completion callback
  40  *        was called and no write error was indicated and a
  41  *        FLUSH request to the device where these blocks are
  42  *        located was received and completed.
  43  *    2b. All referenced blocks need to have a generation
  44  *        number which is equal to the parent's number.
  45  *
  46  * One issue that was found using this module was that the log
  47  * tree on disk became temporarily corrupted because disk blocks
  48  * that had been in use for the log tree had been freed and
  49  * reused too early, while being referenced by the written super
  50  * block.
  51  *
  52  * The search term in the kernel log that can be used to filter
  53  * on the existence of detected integrity issues is
  54  * "btrfs: attempt".
  55  *
  56  * The integrity check is enabled via mount options. These
  57  * mount options are only supported if the integrity check
  58  * tool is compiled by defining BTRFS_FS_CHECK_INTEGRITY.
  59  *
  60  * Example #1, apply integrity checks to all metadata:
  61  * mount /dev/sdb1 /mnt -o check_int
  62  *
  63  * Example #2, apply integrity checks to all metadata and
  64  * to data extents:
  65  * mount /dev/sdb1 /mnt -o check_int_data
  66  *
  67  * Example #3, apply integrity checks to all metadata and dump
  68  * the tree that the super block references to kernel messages
  69  * each time after a super block was written:
  70  * mount /dev/sdb1 /mnt -o check_int,check_int_print_mask=263
  71  *
  72  * If the integrity check tool is included and activated in
  73  * the mount options, plenty of kernel memory is used, and
  74  * plenty of additional CPU cycles are spent. Enabling this
  75  * functionality is not intended for normal use. In most
  76  * cases, unless you are a btrfs developer who needs to verify
  77  * the integrity of (super)-block write requests, do not
  78  * enable the config option BTRFS_FS_CHECK_INTEGRITY to
  79  * include and compile the integrity check tool.
  80  *
  81  * Expect millions of lines of information in the kernel log with an
  82  * enabled check_int_print_mask. Therefore set LOG_BUF_SHIFT in the
  83  * kernel config to at least 26 (which is 64MB). Usually the value is
  84  * limited to 21 (which is 2MB) in init/Kconfig. The file needs to be
  85  * changed like this before LOG_BUF_SHIFT can be set to a high value:
  86  * config LOG_BUF_SHIFT
  87  *       int "Kernel log buffer size (16 => 64KB, 17 => 128KB)"
  88  *       range 12 30
  89  */
  90
  91 #include <linux/sched.h>
  92 #include <linux/slab.h>
  93 #include <linux/buffer_head.h>
  94 #include <linux/mutex.h>
  95 #include <linux/genhd.h>
  96 #include <linux/blkdev.h>
  97 #include "ctree.h"
  98 #include "disk-io.h"
  99 #include "hash.h"
 100 #include "transaction.h"
 101 #include "extent_io.h"
 102 #include "volumes.h"
 103 #include "print-tree.h"
 104 #include "locking.h"
 105 #include "check-integrity.h"
 106 #include "rcu-string.h"
 107
 108 #define BTRFSIC_BLOCK_HASHTABLE_SIZE 0x10000
 109 #define BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE 0x10000
 110 #define BTRFSIC_DEV2STATE_HASHTABLE_SIZE 0x100
 111 #define BTRFSIC_BLOCK_MAGIC_NUMBER 0x14491051
 112 #define BTRFSIC_BLOCK_LINK_MAGIC_NUMBER 0x11070807
 113 #define BTRFSIC_DEV2STATE_MAGIC_NUMBER 0x20111530
 114 #define BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER 20111300
 115 #define BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL (200 - 6)    /* in characters,
 116                                                          * excluding " [...]" */
 117 #define BTRFSIC_GENERATION_UNKNOWN ((u64)-1)
 118
 119 /*
 120  * The definition of the bitmask fields for the print_mask.
 121  * They are specified with the mount option check_integrity_print_mask.
 122  */
 123 #define BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE                     0x00000001
 124 #define BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION         0x00000002
 125 #define BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE                  0x00000004
 126 #define BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE                 0x00000008
 127 #define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH                        0x00000010
 128 #define BTRFSIC_PRINT_MASK_END_IO_BIO_BH                        0x00000020
 129 #define BTRFSIC_PRINT_MASK_VERBOSE                              0x00000040
 130 #define BTRFSIC_PRINT_MASK_VERY_VERBOSE                         0x00000080
 131 #define BTRFSIC_PRINT_MASK_INITIAL_TREE                         0x00000100
 132 #define BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES                    0x00000200
 133 #define BTRFSIC_PRINT_MASK_INITIAL_DATABASE                     0x00000400
 134 #define BTRFSIC_PRINT_MASK_NUM_COPIES                           0x00000800
 135 #define BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS                0x00001000
 136 #define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE                0x00002000
 137
 138 struct btrfsic_dev_state;
 139 struct btrfsic_state;
 140
 141 struct btrfsic_block {
 142         u32 magic_num;          /* only used for debug purposes */
 143         unsigned int is_metadata:1;     /* if it is meta-data, not data-data */
 144         unsigned int is_superblock:1;   /* if it is one of the superblocks */
 145         unsigned int is_iodone:1;       /* if is done by lower subsystem */
 146         unsigned int iodone_w_error:1;  /* error was indicated to endio */
 147         unsigned int never_written:1;   /* block was added because it was
 148                                          * referenced, not because it was
 149                                          * written */
 150         unsigned int mirror_num;        /* large enough to hold
 151                                          * BTRFS_SUPER_MIRROR_MAX */
 152         struct btrfsic_dev_state *dev_state;
 153         u64 dev_bytenr;         /* key, physical byte num on disk */
 154         u64 logical_bytenr;     /* logical byte num on disk */
 155         u64 generation;
 156         struct btrfs_disk_key disk_key; /* extra info to print in case of
 157                                          * issues, will not always be correct */
 158         struct list_head collision_resolving_node;      /* list node */
 159         struct list_head all_blocks_node;       /* list node */
 160
 161         /* the following two lists contain block_link items */
 162         struct list_head ref_to_list;   /* list */
 163         struct list_head ref_from_list; /* list */
 164         struct btrfsic_block *next_in_same_bio;
 165         void *orig_bio_bh_private;
 166         union {
 167                 bio_end_io_t *bio;
 168                 bh_end_io_t *bh;
 169         } orig_bio_bh_end_io;
 170         int submit_bio_bh_rw;
 171         u64 flush_gen; /* only valid if !never_written */
 172 };
 173
 174 /*
 175  * Elements of this type are allocated dynamically and required because
 176  * each block object can refer to and can be ref from multiple blocks.
 177  * The key to lookup them in the hashtable is the dev_bytenr of
 178  * the block ref to plus the one from the block refered from.
 179  * The fact that they are searchable via a hashtable and that a
 180  * ref_cnt is maintained is not required for the btrfs integrity
 181  * check algorithm itself, it is only used to make the output more
 182  * beautiful in case that an error is detected (an error is defined
 183  * as a write operation to a block while that block is still referenced).
 184  */
 185 struct btrfsic_block_link {
 186         u32 magic_num;          /* only used for debug purposes */
 187         u32 ref_cnt;
 188         struct list_head node_ref_to;   /* list node */
 189         struct list_head node_ref_from; /* list node */
 190         struct list_head collision_resolving_node;      /* list node */
 191         struct btrfsic_block *block_ref_to;
 192         struct btrfsic_block *block_ref_from;
 193         u64 parent_generation;
 194 };
 195
 196 struct btrfsic_dev_state {
 197         u32 magic_num;          /* only used for debug purposes */
 198         struct block_device *bdev;
 199         struct btrfsic_state *state;
 200         struct list_head collision_resolving_node;      /* list node */
 201         struct btrfsic_block dummy_block_for_bio_bh_flush;
 202         u64 last_flush_gen;
 203         char name[BDEVNAME_SIZE];
 204 };
 205
 206 struct btrfsic_block_hashtable {
 207         struct list_head table[BTRFSIC_BLOCK_HASHTABLE_SIZE];
 208 };
 209
 210 struct btrfsic_block_link_hashtable {
 211         struct list_head table[BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE];
 212 };
 213
 214 struct btrfsic_dev_state_hashtable {
 215         struct list_head table[BTRFSIC_DEV2STATE_HASHTABLE_SIZE];
 216 };
 217
 218 struct btrfsic_block_data_ctx {
 219         u64 start;              /* virtual bytenr */
 220         u64 dev_bytenr;         /* physical bytenr on device */
 221         u32 len;
 222         struct btrfsic_dev_state *dev;
 223         char **datav;
 224         struct page **pagev;
 225         void *mem_to_free;
 226 };
 227
 228 /* This structure is used to implement recursion without occupying
 229  * any stack space, refer to btrfsic_process_metablock() */
 230 struct btrfsic_stack_frame {
 231         u32 magic;
 232         u32 nr;
 233         int error;
 234         int i;
 235         int limit_nesting;
 236         int num_copies;
 237         int mirror_num;
 238         struct btrfsic_block *block;
 239         struct btrfsic_block_data_ctx *block_ctx;
 240         struct btrfsic_block *next_block;
 241         struct btrfsic_block_data_ctx next_block_ctx;
 242         struct btrfs_header *hdr;
 243         struct btrfsic_stack_frame *prev;
 244 };
 245
 246 /* Some state per mounted filesystem */
 247 struct btrfsic_state {
 248         u32 print_mask;
 249         int include_extent_data;
 250         int csum_size;
 251         struct list_head all_blocks_list;
 252         struct btrfsic_block_hashtable block_hashtable;
 253         struct btrfsic_block_link_hashtable block_link_hashtable;
 254         struct btrfs_root *root;
 255         u64 max_superblock_generation;
 256         struct btrfsic_block *latest_superblock;
 257         u32 metablock_size;
 258         u32 datablock_size;
 259 };
 260
 261 static void btrfsic_block_init(struct btrfsic_block *b);
 262 static struct btrfsic_block *btrfsic_block_alloc(void);
 263 static void btrfsic_block_free(struct btrfsic_block *b);
 264 static void btrfsic_block_link_init(struct btrfsic_block_link *n);
 265 static struct btrfsic_block_link *btrfsic_block_link_alloc(void);
 266 static void btrfsic_block_link_free(struct btrfsic_block_link *n);
 267 static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds);
 268 static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void);
 269 static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds);
 270 static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h);
 271 static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
 272                                         struct btrfsic_block_hashtable *h);
 273 static void btrfsic_block_hashtable_remove(struct btrfsic_block *b);
 274 static struct btrfsic_block *btrfsic_block_hashtable_lookup(
 275                 struct block_device *bdev,
 276                 u64 dev_bytenr,
 277                 struct btrfsic_block_hashtable *h);
 278 static void btrfsic_block_link_hashtable_init(
 279                 struct btrfsic_block_link_hashtable *h);
 280 static void btrfsic_block_link_hashtable_add(
 281                 struct btrfsic_block_link *l,
 282                 struct btrfsic_block_link_hashtable *h);
 283 static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l);
 284 static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
 285                 struct block_device *bdev_ref_to,
 286                 u64 dev_bytenr_ref_to,
 287                 struct block_device *bdev_ref_from,
 288                 u64 dev_bytenr_ref_from,
 289                 struct btrfsic_block_link_hashtable *h);
 290 static void btrfsic_dev_state_hashtable_init(
 291                 struct btrfsic_dev_state_hashtable *h);
 292 static void btrfsic_dev_state_hashtable_add(
 293                 struct btrfsic_dev_state *ds,
 294                 struct btrfsic_dev_state_hashtable *h);
 295 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds);
 296 static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
 297                 struct block_device *bdev,
 298                 struct btrfsic_dev_state_hashtable *h);
 299 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void);
 300 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf);
 301 static int btrfsic_process_superblock(struct btrfsic_state *state,
 302                                       struct btrfs_fs_devices *fs_devices);
 303 static int btrfsic_process_metablock(struct btrfsic_state *state,
 304                                      struct btrfsic_block *block,
 305                                      struct btrfsic_block_data_ctx *block_ctx,
 306                                      int limit_nesting, int force_iodone_flag);
 307 static void btrfsic_read_from_block_data(
 308         struct btrfsic_block_data_ctx *block_ctx,
 309         void *dst, u32 offset, size_t len);
 310 static int btrfsic_create_link_to_next_block(
 311                 struct btrfsic_state *state,
 312                 struct btrfsic_block *block,
 313                 struct btrfsic_block_data_ctx
 314                 *block_ctx, u64 next_bytenr,
 315                 int limit_nesting,
 316                 struct btrfsic_block_data_ctx *next_block_ctx,
 317                 struct btrfsic_block **next_blockp,
 318                 int force_iodone_flag,
 319                 int *num_copiesp, int *mirror_nump,
 320                 struct btrfs_disk_key *disk_key,
 321                 u64 parent_generation);
 322 static int btrfsic_handle_extent_data(struct btrfsic_state *state,
 323                                       struct btrfsic_block *block,
 324                                       struct btrfsic_block_data_ctx *block_ctx,
 325                                       u32 item_offset, int force_iodone_flag);
 326 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
 327                              struct btrfsic_block_data_ctx *block_ctx_out,
 328                              int mirror_num);
 329 static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
 330                                   u32 len, struct block_device *bdev,
 331                                   struct btrfsic_block_data_ctx *block_ctx_out);
 332 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx);
 333 static int btrfsic_read_block(struct btrfsic_state *state,
 334                               struct btrfsic_block_data_ctx *block_ctx);
 335 static void btrfsic_dump_database(struct btrfsic_state *state);
 336 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
 337                                      char **datav, unsigned int num_pages);
 338 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
 339                                           u64 dev_bytenr, char **mapped_datav,
 340                                           unsigned int num_pages,
 341                                           struct bio *bio, int *bio_is_patched,
 342                                           struct buffer_head *bh,
 343                                           int submit_bio_bh_rw);
 344 static int btrfsic_process_written_superblock(
 345                 struct btrfsic_state *state,
 346                 struct btrfsic_block *const block,
 347                 struct btrfs_super_block *const super_hdr);
 348 static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status);
 349 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate);
 350 static int btrfsic_is_block_ref_by_superblock(const struct btrfsic_state *state,
 351                                               const struct btrfsic_block *block,
 352                                               int recursion_level);
 353 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
 354                                         struct btrfsic_block *const block,
 355                                         int recursion_level);
 356 static void btrfsic_print_add_link(const struct btrfsic_state *state,
 357                                    const struct btrfsic_block_link *l);
 358 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
 359                                    const struct btrfsic_block_link *l);
 360 static char btrfsic_get_block_type(const struct btrfsic_state *state,
 361                                    const struct btrfsic_block *block);
 362 static void btrfsic_dump_tree(const struct btrfsic_state *state);
 363 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
 364                                   const struct btrfsic_block *block,
 365                                   int indent_level);
 366 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
 367                 struct btrfsic_state *state,
 368                 struct btrfsic_block_data_ctx *next_block_ctx,
 369                 struct btrfsic_block *next_block,
 370                 struct btrfsic_block *from_block,
 371                 u64 parent_generation);
 372 static struct btrfsic_block *btrfsic_block_lookup_or_add(
 373                 struct btrfsic_state *state,
 374                 struct btrfsic_block_data_ctx *block_ctx,
 375                 const char *additional_string,
 376                 int is_metadata,
 377                 int is_iodone,
 378                 int never_written,
 379                 int mirror_num,
 380                 int *was_created);
 381 static int btrfsic_process_superblock_dev_mirror(
 382                 struct btrfsic_state *state,
 383                 struct btrfsic_dev_state *dev_state,
 384                 struct btrfs_device *device,
 385                 int superblock_mirror_num,
 386                 struct btrfsic_dev_state **selected_dev_state,
 387                 struct btrfs_super_block *selected_super);
 388 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
 389                 struct block_device *bdev);
 390 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
 391                                            u64 bytenr,
 392                                            struct btrfsic_dev_state *dev_state,
 393                                            u64 dev_bytenr);
 394
 395 static struct mutex btrfsic_mutex;
 396 static int btrfsic_is_initialized;
 397 static struct btrfsic_dev_state_hashtable btrfsic_dev_state_hashtable;
 398
 399
 400 static void btrfsic_block_init(struct btrfsic_block *b)
 401 {
 402         b->magic_num = BTRFSIC_BLOCK_MAGIC_NUMBER;
 403         b->dev_state = NULL;
 404         b->dev_bytenr = 0;
 405         b->logical_bytenr = 0;
 406         b->generation = BTRFSIC_GENERATION_UNKNOWN;
 407         b->disk_key.objectid = 0;
 408         b->disk_key.type = 0;
 409         b->disk_key.offset = 0;
 410         b->is_metadata = 0;
 411         b->is_superblock = 0;
 412         b->is_iodone = 0;
 413         b->iodone_w_error = 0;
 414         b->never_written = 0;
 415         b->mirror_num = 0;
 416         b->next_in_same_bio = NULL;
 417         b->orig_bio_bh_private = NULL;
 418         b->orig_bio_bh_end_io.bio = NULL;
 419         INIT_LIST_HEAD(&b->collision_resolving_node);
 420         INIT_LIST_HEAD(&b->all_blocks_node);
 421         INIT_LIST_HEAD(&b->ref_to_list);
 422         INIT_LIST_HEAD(&b->ref_from_list);
 423         b->submit_bio_bh_rw = 0;
 424         b->flush_gen = 0;
 425 }
 426
 427 static struct btrfsic_block *btrfsic_block_alloc(void)
 428 {
 429         struct btrfsic_block *b;
 430
 431         b = kzalloc(sizeof(*b), GFP_NOFS);
 432         if (NULL != b)
 433                 btrfsic_block_init(b);
 434
 435         return b;
 436 }
 437
 438 static void btrfsic_block_free(struct btrfsic_block *b)
 439 {
 440         BUG_ON(!(NULL == b || BTRFSIC_BLOCK_MAGIC_NUMBER == b->magic_num));
 441         kfree(b);
 442 }
 443
 444 static void btrfsic_block_link_init(struct btrfsic_block_link *l)
 445 {
 446         l->magic_num = BTRFSIC_BLOCK_LINK_MAGIC_NUMBER;
 447         l->ref_cnt = 1;
 448         INIT_LIST_HEAD(&l->node_ref_to);
 449         INIT_LIST_HEAD(&l->node_ref_from);
 450         INIT_LIST_HEAD(&l->collision_resolving_node);
 451         l->block_ref_to = NULL;
 452         l->block_ref_from = NULL;
 453 }
 454
 455 static struct btrfsic_block_link *btrfsic_block_link_alloc(void)
 456 {
 457         struct btrfsic_block_link *l;
 458
 459         l = kzalloc(sizeof(*l), GFP_NOFS);
 460         if (NULL != l)
 461                 btrfsic_block_link_init(l);
 462
 463         return l;
 464 }
 465
 466 static void btrfsic_block_link_free(struct btrfsic_block_link *l)
 467 {
 468         BUG_ON(!(NULL == l || BTRFSIC_BLOCK_LINK_MAGIC_NUMBER == l->magic_num));
 469         kfree(l);
 470 }
 471
 472 static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds)
 473 {
 474         ds->magic_num = BTRFSIC_DEV2STATE_MAGIC_NUMBER;
 475         ds->bdev = NULL;
 476         ds->state = NULL;
 477         ds->name[0] = '\0';
 478         INIT_LIST_HEAD(&ds->collision_resolving_node);
 479         ds->last_flush_gen = 0;
 480         btrfsic_block_init(&ds->dummy_block_for_bio_bh_flush);
 481         ds->dummy_block_for_bio_bh_flush.is_iodone = 1;
 482         ds->dummy_block_for_bio_bh_flush.dev_state = ds;
 483 }
 484
 485 static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void)
 486 {
 487         struct btrfsic_dev_state *ds;
 488
 489         ds = kzalloc(sizeof(*ds), GFP_NOFS);
 490         if (NULL != ds)
 491                 btrfsic_dev_state_init(ds);
 492
 493         return ds;
 494 }
 495
 496 static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds)
 497 {
 498         BUG_ON(!(NULL == ds ||
 499                  BTRFSIC_DEV2STATE_MAGIC_NUMBER == ds->magic_num));
 500         kfree(ds);
 501 }
 502
 503 static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h)
 504 {
 505         int i;
 506
 507         for (i = 0; i < BTRFSIC_BLOCK_HASHTABLE_SIZE; i++)
 508                 INIT_LIST_HEAD(h->table + i);
 509 }
 510
 511 static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
 512                                         struct btrfsic_block_hashtable *h)
 513 {
 514         const unsigned int hashval =
 515             (((unsigned int)(b->dev_bytenr >> 16)) ^
 516              ((unsigned int)((uintptr_t)b->dev_state->bdev))) &
 517              (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
 518
 519         list_add(&b->collision_resolving_node, h->table + hashval);
 520 }
 521
 522 static void btrfsic_block_hashtable_remove(struct btrfsic_block *b)
 523 {
 524         list_del(&b->collision_resolving_node);
 525 }
 526
 527 static struct btrfsic_block *btrfsic_block_hashtable_lookup(
 528                 struct block_device *bdev,
 529                 u64 dev_bytenr,
 530                 struct btrfsic_block_hashtable *h)
 531 {
 532         const unsigned int hashval =
 533             (((unsigned int)(dev_bytenr >> 16)) ^
 534              ((unsigned int)((uintptr_t)bdev))) &
 535              (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
 536         struct list_head *elem;
 537
 538         list_for_each(elem, h->table + hashval) {
 539                 struct btrfsic_block *const b =
 540                     list_entry(elem, struct btrfsic_block,
 541                                collision_resolving_node);
 542
 543                 if (b->dev_state->bdev == bdev && b->dev_bytenr == dev_bytenr)
 544                         return b;
 545         }
 546
 547         return NULL;
 548 }
 549
 550 static void btrfsic_block_link_hashtable_init(
 551                 struct btrfsic_block_link_hashtable *h)
 552 {
 553         int i;
 554
 555         for (i = 0; i < BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE; i++)
 556                 INIT_LIST_HEAD(h->table + i);
 557 }
 558
 559 static void btrfsic_block_link_hashtable_add(
 560                 struct btrfsic_block_link *l,
 561                 struct btrfsic_block_link_hashtable *h)
 562 {
 563         const unsigned int hashval =
 564             (((unsigned int)(l->block_ref_to->dev_bytenr >> 16)) ^
 565              ((unsigned int)(l->block_ref_from->dev_bytenr >> 16)) ^
 566              ((unsigned int)((uintptr_t)l->block_ref_to->dev_state->bdev)) ^
 567              ((unsigned int)((uintptr_t)l->block_ref_from->dev_state->bdev)))
 568              & (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
 569
 570         BUG_ON(NULL == l->block_ref_to);
 571         BUG_ON(NULL == l->block_ref_from);
 572         list_add(&l->collision_resolving_node, h->table + hashval);
 573 }
 574
 575 static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l)
 576 {
 577         list_del(&l->collision_resolving_node);
 578 }
 579
 580 static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
 581                 struct block_device *bdev_ref_to,
 582                 u64 dev_bytenr_ref_to,
 583                 struct block_device *bdev_ref_from,
 584                 u64 dev_bytenr_ref_from,
 585                 struct btrfsic_block_link_hashtable *h)
 586 {
 587         const unsigned int hashval =
 588             (((unsigned int)(dev_bytenr_ref_to >> 16)) ^
 589              ((unsigned int)(dev_bytenr_ref_from >> 16)) ^
 590              ((unsigned int)((uintptr_t)bdev_ref_to)) ^
 591              ((unsigned int)((uintptr_t)bdev_ref_from))) &
 592              (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
 593         struct list_head *elem;
 594
 595         list_for_each(elem, h->table + hashval) {
 596                 struct btrfsic_block_link *const l =
 597                     list_entry(elem, struct btrfsic_block_link,
 598                                collision_resolving_node);
 599
 600                 BUG_ON(NULL == l->block_ref_to);
 601                 BUG_ON(NULL == l->block_ref_from);
 602                 if (l->block_ref_to->dev_state->bdev == bdev_ref_to &&
 603                     l->block_ref_to->dev_bytenr == dev_bytenr_ref_to &&
 604                     l->block_ref_from->dev_state->bdev == bdev_ref_from &&
 605                     l->block_ref_from->dev_bytenr == dev_bytenr_ref_from)
 606                         return l;
 607         }
 608
 609         return NULL;
 610 }
 611
 612 static void btrfsic_dev_state_hashtable_init(
 613                 struct btrfsic_dev_state_hashtable *h)
 614 {
 615         int i;
 616
 617         for (i = 0; i < BTRFSIC_DEV2STATE_HASHTABLE_SIZE; i++)
 618                 INIT_LIST_HEAD(h->table + i);
 619 }
 620
 621 static void btrfsic_dev_state_hashtable_add(
 622                 struct btrfsic_dev_state *ds,
 623                 struct btrfsic_dev_state_hashtable *h)
 624 {
 625         const unsigned int hashval =
 626             (((unsigned int)((uintptr_t)ds->bdev)) &
 627              (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
 628
 629         list_add(&ds->collision_resolving_node, h->table + hashval);
 630 }
 631
 632 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds)
 633 {
 634         list_del(&ds->collision_resolving_node);
 635 }
 636
 637 static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
 638                 struct block_device *bdev,
 639                 struct btrfsic_dev_state_hashtable *h)
 640 {
 641         const unsigned int hashval =
 642             (((unsigned int)((uintptr_t)bdev)) &
 643              (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
 644         struct list_head *elem;
 645
 646         list_for_each(elem, h->table + hashval) {
 647                 struct btrfsic_dev_state *const ds =
 648                     list_entry(elem, struct btrfsic_dev_state,
 649                                collision_resolving_node);
 650
 651                 if (ds->bdev == bdev)
 652                         return ds;
 653         }
 654
 655         return NULL;
 656 }
 657
 658 static int btrfsic_process_superblock(struct btrfsic_state *state,
 659                                       struct btrfs_fs_devices *fs_devices)
 660 {
 661         int ret = 0;
 662         struct btrfs_super_block *selected_super;
 663         struct list_head *dev_head = &fs_devices->devices;
 664         struct btrfs_device *device;
 665         struct btrfsic_dev_state *selected_dev_state = NULL;
 666         int pass;
 667
 668         BUG_ON(NULL == state);
 669         selected_super = kzalloc(sizeof(*selected_super), GFP_NOFS);
 670         if (NULL == selected_super) {
 671                 printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
 672                 return -1;
 673         }
 674
 675         list_for_each_entry(device, dev_head, dev_list) {
 676                 int i;
 677                 struct btrfsic_dev_state *dev_state;
 678
 679                 if (!device->bdev || !device->name)
 680                         continue;
 681
 682                 dev_state = btrfsic_dev_state_lookup(device->bdev);
 683                 BUG_ON(NULL == dev_state);
 684                 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 685                         ret = btrfsic_process_superblock_dev_mirror(
 686                                         state, dev_state, device, i,
 687                                         &selected_dev_state, selected_super);
 688                         if (0 != ret && 0 == i) {
 689                                 kfree(selected_super);
 690                                 return ret;
 691                         }
 692                 }
 693         }
 694
 695         if (NULL == state->latest_superblock) {
 696                 printk(KERN_INFO "btrfsic: no superblock found!\n");
 697                 kfree(selected_super);
 698                 return -1;
 699         }
 700
 701         state->csum_size = btrfs_super_csum_size(selected_super);
 702
 703         for (pass = 0; pass < 3; pass++) {
 704                 int num_copies;
 705                 int mirror_num;
 706                 u64 next_bytenr;
 707
 708                 switch (pass) {
 709                 case 0:
 710                         next_bytenr = btrfs_super_root(selected_super);
 711                         if (state->print_mask &
 712                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 713                                 printk(KERN_INFO "root@%llu\n", next_bytenr);
 714                         break;
 715                 case 1:
 716                         next_bytenr = btrfs_super_chunk_root(selected_super);
 717                         if (state->print_mask &
 718                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 719                                 printk(KERN_INFO "chunk@%llu\n", next_bytenr);
 720                         break;
 721                 case 2:
 722                         next_bytenr = btrfs_super_log_root(selected_super);
 723                         if (0 == next_bytenr)
 724                                 continue;
 725                         if (state->print_mask &
 726                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 727                                 printk(KERN_INFO "log@%llu\n", next_bytenr);
 728                         break;
 729                 }
 730
 731                 num_copies =
 732                     btrfs_num_copies(state->root->fs_info,
 733                                      next_bytenr, state->metablock_size);
 734                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 735                         printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
 736                                next_bytenr, num_copies);
 737
 738                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 739                         struct btrfsic_block *next_block;
 740                         struct btrfsic_block_data_ctx tmp_next_block_ctx;
 741                         struct btrfsic_block_link *l;
 742
 743                         ret = btrfsic_map_block(state, next_bytenr,
 744                                                 state->metablock_size,
 745                                                 &tmp_next_block_ctx,
 746                                                 mirror_num);
 747                         if (ret) {
 748                                 printk(KERN_INFO "btrfsic:"
 749                                        " btrfsic_map_block(root @%llu,"
 750                                        " mirror %d) failed!\n",
 751                                        next_bytenr, mirror_num);
 752                                 kfree(selected_super);
 753                                 return -1;
 754                         }
 755
 756                         next_block = btrfsic_block_hashtable_lookup(
 757                                         tmp_next_block_ctx.dev->bdev,
 758                                         tmp_next_block_ctx.dev_bytenr,
 759                                         &state->block_hashtable);
 760                         BUG_ON(NULL == next_block);
 761
 762                         l = btrfsic_block_link_hashtable_lookup(
 763                                         tmp_next_block_ctx.dev->bdev,
 764                                         tmp_next_block_ctx.dev_bytenr,
 765                                         state->latest_superblock->dev_state->
 766                                         bdev,
 767                                         state->latest_superblock->dev_bytenr,
 768                                         &state->block_link_hashtable);
 769                         BUG_ON(NULL == l);
 770
 771                         ret = btrfsic_read_block(state, &tmp_next_block_ctx);
 772                         if (ret < (int)PAGE_CACHE_SIZE) {
 773                                 printk(KERN_INFO
 774                                        "btrfsic: read @logical %llu failed!\n",
 775                                        tmp_next_block_ctx.start);
 776                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
 777                                 kfree(selected_super);
 778                                 return -1;
 779                         }
 780
 781                         ret = btrfsic_process_metablock(state,
 782                                                         next_block,
 783                                                         &tmp_next_block_ctx,
 784                                                         BTRFS_MAX_LEVEL + 3, 1);
 785                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
 786                 }
 787         }
 788
 789         kfree(selected_super);
 790         return ret;
 791 }
 792
 793 static int btrfsic_process_superblock_dev_mirror(
 794                 struct btrfsic_state *state,
 795                 struct btrfsic_dev_state *dev_state,
 796                 struct btrfs_device *device,
 797                 int superblock_mirror_num,
 798                 struct btrfsic_dev_state **selected_dev_state,
 799                 struct btrfs_super_block *selected_super)
 800 {
 801         struct btrfs_super_block *super_tmp;
 802         u64 dev_bytenr;
 803         struct buffer_head *bh;
 804         struct btrfsic_block *superblock_tmp;
 805         int pass;
 806         struct block_device *const superblock_bdev = device->bdev;
 807
 808         /* super block bytenr is always the unmapped device bytenr */
 809         dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
 810         if (dev_bytenr + BTRFS_SUPER_INFO_SIZE > device->total_bytes)
 811                 return -1;
 812         bh = __bread(superblock_bdev, dev_bytenr / 4096,
 813                      BTRFS_SUPER_INFO_SIZE);
 814         if (NULL == bh)
 815                 return -1;
 816         super_tmp = (struct btrfs_super_block *)
 817             (bh->b_data + (dev_bytenr & 4095));
 818
 819         if (btrfs_super_bytenr(super_tmp) != dev_bytenr ||
 820             btrfs_super_magic(super_tmp) != BTRFS_MAGIC ||
 821             memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE) ||
 822             btrfs_super_nodesize(super_tmp) != state->metablock_size ||
 823             btrfs_super_leafsize(super_tmp) != state->metablock_size ||
 824             btrfs_super_sectorsize(super_tmp) != state->datablock_size) {
 825                 brelse(bh);
 826                 return 0;
 827         }
 828
 829         superblock_tmp =
 830             btrfsic_block_hashtable_lookup(superblock_bdev,
 831                                            dev_bytenr,
 832                                            &state->block_hashtable);
 833         if (NULL == superblock_tmp) {
 834                 superblock_tmp = btrfsic_block_alloc();
 835                 if (NULL == superblock_tmp) {
 836                         printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
 837                         brelse(bh);
 838                         return -1;
 839                 }
 840                 /* for superblock, only the dev_bytenr makes sense */
 841                 superblock_tmp->dev_bytenr = dev_bytenr;
 842                 superblock_tmp->dev_state = dev_state;
 843                 superblock_tmp->logical_bytenr = dev_bytenr;
 844                 superblock_tmp->generation = btrfs_super_generation(super_tmp);
 845                 superblock_tmp->is_metadata = 1;
 846                 superblock_tmp->is_superblock = 1;
 847                 superblock_tmp->is_iodone = 1;
 848                 superblock_tmp->never_written = 0;
 849                 superblock_tmp->mirror_num = 1 + superblock_mirror_num;
 850                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
 851                         printk_in_rcu(KERN_INFO "New initial S-block (bdev %p, %s)"
 852                                      " @%llu (%s/%llu/%d)\n",
 853                                      superblock_bdev,
 854                                      rcu_str_deref(device->name), dev_bytenr,
 855                                      dev_state->name, dev_bytenr,
 856                                      superblock_mirror_num);
 857                 list_add(&superblock_tmp->all_blocks_node,
 858                          &state->all_blocks_list);
 859                 btrfsic_block_hashtable_add(superblock_tmp,
 860                                             &state->block_hashtable);
 861         }
 862
 863         /* select the one with the highest generation field */
 864         if (btrfs_super_generation(super_tmp) >
 865             state->max_superblock_generation ||
 866             0 == state->max_superblock_generation) {
 867                 memcpy(selected_super, super_tmp, sizeof(*selected_super));
 868                 *selected_dev_state = dev_state;
 869                 state->max_superblock_generation =
 870                     btrfs_super_generation(super_tmp);
 871                 state->latest_superblock = superblock_tmp;
 872         }
 873
 874         for (pass = 0; pass < 3; pass++) {
 875                 u64 next_bytenr;
 876                 int num_copies;
 877                 int mirror_num;
 878                 const char *additional_string = NULL;
 879                 struct btrfs_disk_key tmp_disk_key;
 880
 881                 tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
 882                 tmp_disk_key.offset = 0;
 883                 switch (pass) {
 884                 case 0:
 885                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 886                                                     BTRFS_ROOT_TREE_OBJECTID);
 887                         additional_string = "initial root ";
 888                         next_bytenr = btrfs_super_root(super_tmp);
 889                         break;
 890                 case 1:
 891                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 892                                                     BTRFS_CHUNK_TREE_OBJECTID);
 893                         additional_string = "initial chunk ";
 894                         next_bytenr = btrfs_super_chunk_root(super_tmp);
 895                         break;
 896                 case 2:
 897                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 898                                                     BTRFS_TREE_LOG_OBJECTID);
 899                         additional_string = "initial log ";
 900                         next_bytenr = btrfs_super_log_root(super_tmp);
 901                         if (0 == next_bytenr)
 902                                 continue;
 903                         break;
 904                 }
 905
 906                 num_copies =
 907                     btrfs_num_copies(state->root->fs_info,
 908                                      next_bytenr, state->metablock_size);
 909                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 910                         printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
 911                                next_bytenr, num_copies);
 912                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 913                         struct btrfsic_block *next_block;
 914                         struct btrfsic_block_data_ctx tmp_next_block_ctx;
 915                         struct btrfsic_block_link *l;
 916
 917                         if (btrfsic_map_block(state, next_bytenr,
 918                                               state->metablock_size,
 919                                               &tmp_next_block_ctx,
 920                                               mirror_num)) {
 921                                 printk(KERN_INFO "btrfsic: btrfsic_map_block("
 922                                        "bytenr @%llu, mirror %d) failed!\n",
 923                                        next_bytenr, mirror_num);
 924                                 brelse(bh);
 925                                 return -1;
 926                         }
 927
 928                         next_block = btrfsic_block_lookup_or_add(
 929                                         state, &tmp_next_block_ctx,
 930                                         additional_string, 1, 1, 0,
 931                                         mirror_num, NULL);
 932                         if (NULL == next_block) {
 933                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
 934                                 brelse(bh);
 935                                 return -1;
 936                         }
 937
 938                         next_block->disk_key = tmp_disk_key;
 939                         next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
 940                         l = btrfsic_block_link_lookup_or_add(
 941                                         state, &tmp_next_block_ctx,
 942                                         next_block, superblock_tmp,
 943                                         BTRFSIC_GENERATION_UNKNOWN);
 944                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
 945                         if (NULL == l) {
 946                                 brelse(bh);
 947                                 return -1;
 948                         }
 949                 }
 950         }
 951         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES)
 952                 btrfsic_dump_tree_sub(state, superblock_tmp, 0);
 953
 954         brelse(bh);
 955         return 0;
 956 }
 957
 958 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void)
 959 {
 960         struct btrfsic_stack_frame *sf;
 961
 962         sf = kzalloc(sizeof(*sf), GFP_NOFS);
 963         if (NULL == sf)
 964                 printk(KERN_INFO "btrfsic: alloc memory failed!\n");
 965         else
 966                 sf->magic = BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER;
 967         return sf;
 968 }
 969
 970 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf)
 971 {
 972         BUG_ON(!(NULL == sf ||
 973                  BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER == sf->magic));
 974         kfree(sf);
 975 }
 976
 977 static int btrfsic_process_metablock(
 978                 struct btrfsic_state *state,
 979                 struct btrfsic_block *const first_block,
 980                 struct btrfsic_block_data_ctx *const first_block_ctx,
 981                 int first_limit_nesting, int force_iodone_flag)
 982 {
 983         struct btrfsic_stack_frame initial_stack_frame = { 0 };
 984         struct btrfsic_stack_frame *sf;
 985         struct btrfsic_stack_frame *next_stack;
 986         struct btrfs_header *const first_hdr =
 987                 (struct btrfs_header *)first_block_ctx->datav[0];
 988
 989         BUG_ON(!first_hdr);
 990         sf = &initial_stack_frame;
 991         sf->error = 0;
 992         sf->i = -1;
 993         sf->limit_nesting = first_limit_nesting;
 994         sf->block = first_block;
 995         sf->block_ctx = first_block_ctx;
 996         sf->next_block = NULL;
 997         sf->hdr = first_hdr;
 998         sf->prev = NULL;
 999
1000 continue_with_new_stack_frame:
1001         sf->block->generation = le64_to_cpu(sf->hdr->generation);
1002         if (0 == sf->hdr->level) {
1003                 struct btrfs_leaf *const leafhdr =
1004                     (struct btrfs_leaf *)sf->hdr;
1005
1006                 if (-1 == sf->i) {
1007                         sf->nr = btrfs_stack_header_nritems(&leafhdr->header);
1008
1009                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1010                                 printk(KERN_INFO
1011                                        "leaf %llu items %d generation %llu"
1012                                        " owner %llu\n",
1013                                        sf->block_ctx->start, sf->nr,
1014                                        btrfs_stack_header_generation(
1015                                                &leafhdr->header),
1016                                        btrfs_stack_header_owner(
1017                                                &leafhdr->header));
1018                 }
1019
1020 continue_with_current_leaf_stack_frame:
1021                 if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1022                         sf->i++;
1023                         sf->num_copies = 0;
1024                 }
1025
1026                 if (sf->i < sf->nr) {
1027                         struct btrfs_item disk_item;
1028                         u32 disk_item_offset =
1029                                 (uintptr_t)(leafhdr->items + sf->i) -
1030                                 (uintptr_t)leafhdr;
1031                         struct btrfs_disk_key *disk_key;
1032                         u8 type;
1033                         u32 item_offset;
1034                         u32 item_size;
1035
1036                         if (disk_item_offset + sizeof(struct btrfs_item) >
1037                             sf->block_ctx->len) {
1038 leaf_item_out_of_bounce_error:
1039                                 printk(KERN_INFO
1040                                        "btrfsic: leaf item out of bounce at logical %llu, dev %s\n",
1041                                        sf->block_ctx->start,
1042                                        sf->block_ctx->dev->name);
1043                                 goto one_stack_frame_backwards;
1044                         }
1045                         btrfsic_read_from_block_data(sf->block_ctx,
1046                                                      &disk_item,
1047                                                      disk_item_offset,
1048                                                      sizeof(struct btrfs_item));
1049                         item_offset = btrfs_stack_item_offset(&disk_item);
1050                         item_size = btrfs_stack_item_size(&disk_item);
1051                         disk_key = &disk_item.key;
1052                         type = btrfs_disk_key_type(disk_key);
1053
1054                         if (BTRFS_ROOT_ITEM_KEY == type) {
1055                                 struct btrfs_root_item root_item;
1056                                 u32 root_item_offset;
1057                                 u64 next_bytenr;
1058
1059                                 root_item_offset = item_offset +
1060                                         offsetof(struct btrfs_leaf, items);
1061                                 if (root_item_offset + item_size >
1062                                     sf->block_ctx->len)
1063                                         goto leaf_item_out_of_bounce_error;
1064                                 btrfsic_read_from_block_data(
1065                                         sf->block_ctx, &root_item,
1066                                         root_item_offset,
1067                                         item_size);
1068                                 next_bytenr = btrfs_root_bytenr(&root_item);
1069
1070                                 sf->error =
1071                                     btrfsic_create_link_to_next_block(
1072                                                 state,
1073                                                 sf->block,
1074                                                 sf->block_ctx,
1075                                                 next_bytenr,
1076                                                 sf->limit_nesting,
1077                                                 &sf->next_block_ctx,
1078                                                 &sf->next_block,
1079                                                 force_iodone_flag,
1080                                                 &sf->num_copies,
1081                                                 &sf->mirror_num,
1082                                                 disk_key,
1083                                                 btrfs_root_generation(
1084                                                 &root_item));
1085                                 if (sf->error)
1086                                         goto one_stack_frame_backwards;
1087
1088                                 if (NULL != sf->next_block) {
1089                                         struct btrfs_header *const next_hdr =
1090                                             (struct btrfs_header *)
1091                                             sf->next_block_ctx.datav[0];
1092
1093                                         next_stack =
1094                                             btrfsic_stack_frame_alloc();
1095                                         if (NULL == next_stack) {
1096                                                 sf->error = -1;
1097                                                 btrfsic_release_block_ctx(
1098                                                                 &sf->
1099                                                                 next_block_ctx);
1100                                                 goto one_stack_frame_backwards;
1101                                         }
1102
1103                                         next_stack->i = -1;
1104                                         next_stack->block = sf->next_block;
1105                                         next_stack->block_ctx =
1106                                             &sf->next_block_ctx;
1107                                         next_stack->next_block = NULL;
1108                                         next_stack->hdr = next_hdr;
1109                                         next_stack->limit_nesting =
1110                                             sf->limit_nesting - 1;
1111                                         next_stack->prev = sf;
1112                                         sf = next_stack;
1113                                         goto continue_with_new_stack_frame;
1114                                 }
1115                         } else if (BTRFS_EXTENT_DATA_KEY == type &&
1116                                    state->include_extent_data) {
1117                                 sf->error = btrfsic_handle_extent_data(
1118                                                 state,
1119                                                 sf->block,
1120                                                 sf->block_ctx,
1121                                                 item_offset,
1122                                                 force_iodone_flag);
1123                                 if (sf->error)
1124                                         goto one_stack_frame_backwards;
1125                         }
1126
1127                         goto continue_with_current_leaf_stack_frame;
1128                 }
1129         } else {
1130                 struct btrfs_node *const nodehdr = (struct btrfs_node *)sf->hdr;
1131
1132                 if (-1 == sf->i) {
1133                         sf->nr = btrfs_stack_header_nritems(&nodehdr->header);
1134
1135                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1136                                 printk(KERN_INFO "node %llu level %d items %d"
1137                                        " generation %llu owner %llu\n",
1138                                        sf->block_ctx->start,
1139                                        nodehdr->header.level, sf->nr,
1140                                        btrfs_stack_header_generation(
1141                                        &nodehdr->header),
1142                                        btrfs_stack_header_owner(
1143                                        &nodehdr->header));
1144                 }
1145
1146 continue_with_current_node_stack_frame:
1147                 if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1148                         sf->i++;
1149                         sf->num_copies = 0;
1150                 }
1151
1152                 if (sf->i < sf->nr) {
1153                         struct btrfs_key_ptr key_ptr;
1154                         u32 key_ptr_offset;
1155                         u64 next_bytenr;
1156
1157                         key_ptr_offset = (uintptr_t)(nodehdr->ptrs + sf->i) -
1158                                           (uintptr_t)nodehdr;
1159                         if (key_ptr_offset + sizeof(struct btrfs_key_ptr) >
1160                             sf->block_ctx->len) {
1161                                 printk(KERN_INFO
1162                                        "btrfsic: node item out of bounce at logical %llu, dev %s\n",
1163                                        sf->block_ctx->start,
1164                                        sf->block_ctx->dev->name);
1165                                 goto one_stack_frame_backwards;
1166                         }
1167                         btrfsic_read_from_block_data(
1168                                 sf->block_ctx, &key_ptr, key_ptr_offset,
1169                                 sizeof(struct btrfs_key_ptr));
1170                         next_bytenr = btrfs_stack_key_blockptr(&key_ptr);
1171
1172                         sf->error = btrfsic_create_link_to_next_block(
1173                                         state,
1174                                         sf->block,
1175                                         sf->block_ctx,
1176                                         next_bytenr,
1177                                         sf->limit_nesting,
1178                                         &sf->next_block_ctx,
1179                                         &sf->next_block,
1180                                         force_iodone_flag,
1181                                         &sf->num_copies,
1182                                         &sf->mirror_num,
1183                                         &key_ptr.key,
1184                                         btrfs_stack_key_generation(&key_ptr));
1185                         if (sf->error)
1186                                 goto one_stack_frame_backwards;
1187
1188                         if (NULL != sf->next_block) {
1189                                 struct btrfs_header *const next_hdr =
1190                                     (struct btrfs_header *)
1191                                     sf->next_block_ctx.datav[0];
1192
1193                                 next_stack = btrfsic_stack_frame_alloc();
1194                                 if (NULL == next_stack) {
1195                                         sf->error = -1;
1196                                         goto one_stack_frame_backwards;
1197                                 }
1198
1199                                 next_stack->i = -1;
1200                                 next_stack->block = sf->next_block;
1201                                 next_stack->block_ctx = &sf->next_block_ctx;
1202                                 next_stack->next_block = NULL;
1203                                 next_stack->hdr = next_hdr;
1204                                 next_stack->limit_nesting =
1205                                     sf->limit_nesting - 1;
1206                                 next_stack->prev = sf;
1207                                 sf = next_stack;
1208                                 goto continue_with_new_stack_frame;
1209                         }
1210
1211                         goto continue_with_current_node_stack_frame;
1212                 }
1213         }
1214
1215 one_stack_frame_backwards:
1216         if (NULL != sf->prev) {
1217                 struct btrfsic_stack_frame *const prev = sf->prev;
1218
1219                 /* the one for the initial block is freed in the caller */
1220                 btrfsic_release_block_ctx(sf->block_ctx);
1221
1222                 if (sf->error) {
1223                         prev->error = sf->error;
1224                         btrfsic_stack_frame_free(sf);
1225                         sf = prev;
1226                         goto one_stack_frame_backwards;
1227                 }
1228
1229                 btrfsic_stack_frame_free(sf);
1230                 sf = prev;
1231                 goto continue_with_new_stack_frame;
1232         } else {
1233                 BUG_ON(&initial_stack_frame != sf);
1234         }
1235
1236         return sf->error;
1237 }
1238
1239 static void btrfsic_read_from_block_data(
1240         struct btrfsic_block_data_ctx *block_ctx,
1241         void *dstv, u32 offset, size_t len)
1242 {
1243         size_t cur;
1244         size_t offset_in_page;
1245         char *kaddr;
1246         char *dst = (char *)dstv;
1247         size_t start_offset = block_ctx->start & ((u64)PAGE_CACHE_SIZE - 1);
1248         unsigned long i = (start_offset + offset) >> PAGE_CACHE_SHIFT;
1249
1250         WARN_ON(offset + len > block_ctx->len);
1251         offset_in_page = (start_offset + offset) & (PAGE_CACHE_SIZE - 1);
1252
1253         while (len > 0) {
1254                 cur = min(len, ((size_t)PAGE_CACHE_SIZE - offset_in_page));
1255                 BUG_ON(i >= (block_ctx->len + PAGE_CACHE_SIZE - 1) >>
1256                             PAGE_CACHE_SHIFT);
1257                 kaddr = block_ctx->datav[i];
1258                 memcpy(dst, kaddr + offset_in_page, cur);
1259
1260                 dst += cur;
1261                 len -= cur;
1262                 offset_in_page = 0;
1263                 i++;
1264         }
1265 }
1266
1267 static int btrfsic_create_link_to_next_block(
1268                 struct btrfsic_state *state,
1269                 struct btrfsic_block *block,
1270                 struct btrfsic_block_data_ctx *block_ctx,
1271                 u64 next_bytenr,
1272                 int limit_nesting,
1273                 struct btrfsic_block_data_ctx *next_block_ctx,
1274                 struct btrfsic_block **next_blockp,
1275                 int force_iodone_flag,
1276                 int *num_copiesp, int *mirror_nump,
1277                 struct btrfs_disk_key *disk_key,
1278                 u64 parent_generation)
1279 {
1280         struct btrfsic_block *next_block = NULL;
1281         int ret;
1282         struct btrfsic_block_link *l;
1283         int did_alloc_block_link;
1284         int block_was_created;
1285
1286         *next_blockp = NULL;
1287         if (0 == *num_copiesp) {
1288                 *num_copiesp =
1289                     btrfs_num_copies(state->root->fs_info,
1290                                      next_bytenr, state->metablock_size);
1291                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1292                         printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1293                                next_bytenr, *num_copiesp);
1294                 *mirror_nump = 1;
1295         }
1296
1297         if (*mirror_nump > *num_copiesp)
1298                 return 0;
1299
1300         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1301                 printk(KERN_INFO
1302                        "btrfsic_create_link_to_next_block(mirror_num=%d)\n",
1303                        *mirror_nump);
1304         ret = btrfsic_map_block(state, next_bytenr,
1305                                 state->metablock_size,
1306                                 next_block_ctx, *mirror_nump);
1307         if (ret) {
1308                 printk(KERN_INFO
1309                        "btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1310                        next_bytenr, *mirror_nump);
1311                 btrfsic_release_block_ctx(next_block_ctx);
1312                 *next_blockp = NULL;
1313                 return -1;
1314         }
1315
1316         next_block = btrfsic_block_lookup_or_add(state,
1317                                                  next_block_ctx, "referenced ",
1318                                                  1, force_iodone_flag,
1319                                                  !force_iodone_flag,
1320                                                  *mirror_nump,
1321                                                  &block_was_created);
1322         if (NULL == next_block) {
1323                 btrfsic_release_block_ctx(next_block_ctx);
1324                 *next_blockp = NULL;
1325                 return -1;
1326         }
1327         if (block_was_created) {
1328                 l = NULL;
1329                 next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
1330         } else {
1331                 if (next_block->logical_bytenr != next_bytenr &&
1332                     !(!next_block->is_metadata &&
1333                       0 == next_block->logical_bytenr)) {
1334                         printk(KERN_INFO
1335                                "Referenced block @%llu (%s/%llu/%d)"
1336                                " found in hash table, %c,"
1337                                " bytenr mismatch (!= stored %llu).\n",
1338                                next_bytenr, next_block_ctx->dev->name,
1339                                next_block_ctx->dev_bytenr, *mirror_nump,
1340                                btrfsic_get_block_type(state, next_block),
1341                                next_block->logical_bytenr);
1342                 } else if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1343                         printk(KERN_INFO
1344                                "Referenced block @%llu (%s/%llu/%d)"
1345                                " found in hash table, %c.\n",
1346                                next_bytenr, next_block_ctx->dev->name,
1347                                next_block_ctx->dev_bytenr, *mirror_nump,
1348                                btrfsic_get_block_type(state, next_block));
1349                 next_block->logical_bytenr = next_bytenr;
1350
1351                 next_block->mirror_num = *mirror_nump;
1352                 l = btrfsic_block_link_hashtable_lookup(
1353                                 next_block_ctx->dev->bdev,
1354                                 next_block_ctx->dev_bytenr,
1355                                 block_ctx->dev->bdev,
1356                                 block_ctx->dev_bytenr,
1357                                 &state->block_link_hashtable);
1358         }
1359
1360         next_block->disk_key = *disk_key;
1361         if (NULL == l) {
1362                 l = btrfsic_block_link_alloc();
1363                 if (NULL == l) {
1364                         printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
1365                         btrfsic_release_block_ctx(next_block_ctx);
1366                         *next_blockp = NULL;
1367                         return -1;
1368                 }
1369
1370                 did_alloc_block_link = 1;
1371                 l->block_ref_to = next_block;
1372                 l->block_ref_from = block;
1373                 l->ref_cnt = 1;
1374                 l->parent_generation = parent_generation;
1375
1376                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1377                         btrfsic_print_add_link(state, l);
1378
1379                 list_add(&l->node_ref_to, &block->ref_to_list);
1380                 list_add(&l->node_ref_from, &next_block->ref_from_list);
1381
1382                 btrfsic_block_link_hashtable_add(l,
1383                                                  &state->block_link_hashtable);
1384         } else {
1385                 did_alloc_block_link = 0;
1386                 if (0 == limit_nesting) {
1387                         l->ref_cnt++;
1388                         l->parent_generation = parent_generation;
1389                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1390                                 btrfsic_print_add_link(state, l);
1391                 }
1392         }
1393
1394         if (limit_nesting > 0 && did_alloc_block_link) {
1395                 ret = btrfsic_read_block(state, next_block_ctx);
1396                 if (ret < (int)next_block_ctx->len) {
1397                         printk(KERN_INFO
1398                                "btrfsic: read block @logical %llu failed!\n",
1399                                next_bytenr);
1400                         btrfsic_release_block_ctx(next_block_ctx);
1401                         *next_blockp = NULL;
1402                         return -1;
1403                 }
1404
1405                 *next_blockp = next_block;
1406         } else {
1407                 *next_blockp = NULL;
1408         }
1409         (*mirror_nump)++;
1410
1411         return 0;
1412 }
1413
1414 static int btrfsic_handle_extent_data(
1415                 struct btrfsic_state *state,
1416                 struct btrfsic_block *block,
1417                 struct btrfsic_block_data_ctx *block_ctx,
1418                 u32 item_offset, int force_iodone_flag)
1419 {
1420         int ret;
1421         struct btrfs_file_extent_item file_extent_item;
1422         u64 file_extent_item_offset;
1423         u64 next_bytenr;
1424         u64 num_bytes;
1425         u64 generation;
1426         struct btrfsic_block_link *l;
1427
1428         file_extent_item_offset = offsetof(struct btrfs_leaf, items) +
1429                                   item_offset;
1430         if (file_extent_item_offset +
1431             offsetof(struct btrfs_file_extent_item, disk_num_bytes) >
1432             block_ctx->len) {
1433                 printk(KERN_INFO
1434                        "btrfsic: file item out of bounce at logical %llu, dev %s\n",
1435                        block_ctx->start, block_ctx->dev->name);
1436                 return -1;
1437         }
1438
1439         btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1440                 file_extent_item_offset,
1441                 offsetof(struct btrfs_file_extent_item, disk_num_bytes));
1442         if (BTRFS_FILE_EXTENT_REG != file_extent_item.type ||
1443             btrfs_stack_file_extent_disk_bytenr(&file_extent_item) == 0) {
1444                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1445                         printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu\n",
1446                                file_extent_item.type,
1447                                btrfs_stack_file_extent_disk_bytenr(
1448                                &file_extent_item));
1449                 return 0;
1450         }
1451
1452         if (file_extent_item_offset + sizeof(struct btrfs_file_extent_item) >
1453             block_ctx->len) {
1454                 printk(KERN_INFO
1455                        "btrfsic: file item out of bounce at logical %llu, dev %s\n",
1456                        block_ctx->start, block_ctx->dev->name);
1457                 return -1;
1458         }
1459         btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1460                                      file_extent_item_offset,
1461                                      sizeof(struct btrfs_file_extent_item));
1462         next_bytenr = btrfs_stack_file_extent_disk_bytenr(&file_extent_item);
1463         if (btrfs_stack_file_extent_compression(&file_extent_item) ==
1464             BTRFS_COMPRESS_NONE) {
1465                 next_bytenr += btrfs_stack_file_extent_offset(&file_extent_item);
1466                 num_bytes = btrfs_stack_file_extent_num_bytes(&file_extent_item);
1467         } else {
1468                 num_bytes = btrfs_stack_file_extent_disk_num_bytes(&file_extent_item);
1469         }
1470         generation = btrfs_stack_file_extent_generation(&file_extent_item);
1471
1472         if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1473                 printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu,"
1474                        " offset = %llu, num_bytes = %llu\n",
1475                        file_extent_item.type,
1476                        btrfs_stack_file_extent_disk_bytenr(&file_extent_item),
1477                        btrfs_stack_file_extent_offset(&file_extent_item),
1478                        num_bytes);
1479         while (num_bytes > 0) {
1480                 u32 chunk_len;
1481                 int num_copies;
1482                 int mirror_num;
1483
1484                 if (num_bytes > state->datablock_size)
1485                         chunk_len = state->datablock_size;
1486                 else
1487                         chunk_len = num_bytes;
1488
1489                 num_copies =
1490                     btrfs_num_copies(state->root->fs_info,
1491                                      next_bytenr, state->datablock_size);
1492                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1493                         printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1494                                next_bytenr, num_copies);
1495                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
1496                         struct btrfsic_block_data_ctx next_block_ctx;
1497                         struct btrfsic_block *next_block;
1498                         int block_was_created;
1499
1500                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1501                                 printk(KERN_INFO "btrfsic_handle_extent_data("
1502                                        "mirror_num=%d)\n", mirror_num);
1503                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1504                                 printk(KERN_INFO
1505                                        "\tdisk_bytenr = %llu, num_bytes %u\n",
1506                                        next_bytenr, chunk_len);
1507                         ret = btrfsic_map_block(state, next_bytenr,
1508                                                 chunk_len, &next_block_ctx,
1509                                                 mirror_num);
1510                         if (ret) {
1511                                 printk(KERN_INFO
1512                                        "btrfsic: btrfsic_map_block(@%llu,"
1513                                        " mirror=%d) failed!\n",
1514                                        next_bytenr, mirror_num);
1515                                 return -1;
1516                         }
1517
1518                         next_block = btrfsic_block_lookup_or_add(
1519                                         state,
1520                                         &next_block_ctx,
1521                                         "referenced ",
1522                                         0,
1523                                         force_iodone_flag,
1524                                         !force_iodone_flag,
1525                                         mirror_num,
1526                                         &block_was_created);
1527                         if (NULL == next_block) {
1528                                 printk(KERN_INFO
1529                                        "btrfsic: error, kmalloc failed!\n");
1530                                 btrfsic_release_block_ctx(&next_block_ctx);
1531                                 return -1;
1532                         }
1533                         if (!block_was_created) {
1534                                 if (next_block->logical_bytenr != next_bytenr &&
1535                                     !(!next_block->is_metadata &&
1536                                       0 == next_block->logical_bytenr)) {
1537                                         printk(KERN_INFO
1538                                                "Referenced block"
1539                                                " @%llu (%s/%llu/%d)"
1540                                                " found in hash table, D,"
1541                                                " bytenr mismatch"
1542                                                " (!= stored %llu).\n",
1543                                                next_bytenr,
1544                                                next_block_ctx.dev->name,
1545                                                next_block_ctx.dev_bytenr,
1546                                                mirror_num,
1547                                                next_block->logical_bytenr);
1548                                 }
1549                                 next_block->logical_bytenr = next_bytenr;
1550                                 next_block->mirror_num = mirror_num;
1551                         }
1552
1553                         l = btrfsic_block_link_lookup_or_add(state,
1554                                                              &next_block_ctx,
1555                                                              next_block, block,
1556                                                              generation);
1557                         btrfsic_release_block_ctx(&next_block_ctx);
1558                         if (NULL == l)
1559                                 return -1;
1560                 }
1561
1562                 next_bytenr += chunk_len;
1563                 num_bytes -= chunk_len;
1564         }
1565
1566         return 0;
1567 }
1568
1569 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
1570                              struct btrfsic_block_data_ctx *block_ctx_out,
1571                              int mirror_num)
1572 {
1573         int ret;
1574         u64 length;
1575         struct btrfs_bio *multi = NULL;
1576         struct btrfs_device *device;
1577
1578         length = len;
1579         ret = btrfs_map_block(state->root->fs_info, READ,
1580                               bytenr, &length, &multi, mirror_num);
1581
1582         if (ret) {
1583                 block_ctx_out->start = 0;
1584                 block_ctx_out->dev_bytenr = 0;
1585                 block_ctx_out->len = 0;
1586                 block_ctx_out->dev = NULL;
1587                 block_ctx_out->datav = NULL;
1588                 block_ctx_out->pagev = NULL;
1589                 block_ctx_out->mem_to_free = NULL;
1590
1591                 return ret;
1592         }
1593
1594         device = multi->stripes[0].dev;
1595         block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev);
1596         block_ctx_out->dev_bytenr = multi->stripes[0].physical;
1597         block_ctx_out->start = bytenr;
1598         block_ctx_out->len = len;
1599         block_ctx_out->datav = NULL;
1600         block_ctx_out->pagev = NULL;
1601         block_ctx_out->mem_to_free = NULL;
1602
1603         kfree(multi);
1604         if (NULL == block_ctx_out->dev) {
1605                 ret = -ENXIO;
1606                 printk(KERN_INFO "btrfsic: error, cannot lookup dev (#1)!\n");
1607         }
1608
1609         return ret;
1610 }
1611
1612 static int btrfsic_map_superblock(struct btrfsic_state *state, u64 bytenr,
1613                                   u32 len, struct block_device *bdev,
1614                                   struct btrfsic_block_data_ctx *block_ctx_out)
1615 {
1616         block_ctx_out->dev = btrfsic_dev_state_lookup(bdev);
1617         block_ctx_out->dev_bytenr = bytenr;
1618         block_ctx_out->start = bytenr;
1619         block_ctx_out->len = len;
1620         block_ctx_out->datav = NULL;
1621         block_ctx_out->pagev = NULL;
1622         block_ctx_out->mem_to_free = NULL;
1623         if (NULL != block_ctx_out->dev) {
1624                 return 0;
1625         } else {
1626                 printk(KERN_INFO "btrfsic: error, cannot lookup dev (#2)!\n");
1627                 return -ENXIO;
1628         }
1629 }
1630
1631 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
1632 {
1633         if (block_ctx->mem_to_free) {
1634                 unsigned int num_pages;
1635
1636                 BUG_ON(!block_ctx->datav);
1637                 BUG_ON(!block_ctx->pagev);
1638                 num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
1639                             PAGE_CACHE_SHIFT;
1640                 while (num_pages > 0) {
1641                         num_pages--;
1642                         if (block_ctx->datav[num_pages]) {
1643                                 kunmap(block_ctx->pagev[num_pages]);
1644                                 block_ctx->datav[num_pages] = NULL;
1645                         }
1646                         if (block_ctx->pagev[num_pages]) {
1647                                 __free_page(block_ctx->pagev[num_pages]);
1648                                 block_ctx->pagev[num_pages] = NULL;
1649                         }
1650                 }
1651
1652                 kfree(block_ctx->mem_to_free);
1653                 block_ctx->mem_to_free = NULL;
1654                 block_ctx->pagev = NULL;
1655                 block_ctx->datav = NULL;
1656         }
1657 }
1658
1659 static int btrfsic_read_block(struct btrfsic_state *state,
1660                               struct btrfsic_block_data_ctx *block_ctx)
1661 {
1662         unsigned int num_pages;
1663         unsigned int i;
1664         u64 dev_bytenr;
1665         int ret;
1666
1667         BUG_ON(block_ctx->datav);
1668         BUG_ON(block_ctx->pagev);
1669         BUG_ON(block_ctx->mem_to_free);
1670         if (block_ctx->dev_bytenr & ((u64)PAGE_CACHE_SIZE - 1)) {
1671                 printk(KERN_INFO
1672                        "btrfsic: read_block() with unaligned bytenr %llu\n",
1673                        block_ctx->dev_bytenr);
1674                 return -1;
1675         }
1676
1677         num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
1678                     PAGE_CACHE_SHIFT;
1679         block_ctx->mem_to_free = kzalloc((sizeof(*block_ctx->datav) +
1680                                           sizeof(*block_ctx->pagev)) *
1681                                          num_pages, GFP_NOFS);
1682         if (!block_ctx->mem_to_free)
1683                 return -1;
1684         block_ctx->datav = block_ctx->mem_to_free;
1685         block_ctx->pagev = (struct page **)(block_ctx->datav + num_pages);
1686         for (i = 0; i < num_pages; i++) {
1687                 block_ctx->pagev[i] = alloc_page(GFP_NOFS);
1688                 if (!block_ctx->pagev[i])
1689                         return -1;
1690         }
1691
1692         dev_bytenr = block_ctx->dev_bytenr;
1693         for (i = 0; i < num_pages;) {
1694                 struct bio *bio;
1695                 unsigned int j;
1696
1697                 bio = btrfs_io_bio_alloc(GFP_NOFS, num_pages - i);
1698                 if (!bio) {
1699                         printk(KERN_INFO
1700                                "btrfsic: bio_alloc() for %u pages failed!\n",
1701                                num_pages - i);
1702                         return -1;
1703                 }
1704                 bio->bi_bdev = block_ctx->dev->bdev;
1705                 bio->bi_iter.bi_sector = dev_bytenr >> 9;
1706
1707                 for (j = i; j < num_pages; j++) {
1708                         ret = bio_add_page(bio, block_ctx->pagev[j],
1709                                            PAGE_CACHE_SIZE, 0);
1710                         if (PAGE_CACHE_SIZE != ret)
1711                                 break;
1712                 }
1713                 if (j == i) {
1714                         printk(KERN_INFO
1715                                "btrfsic: error, failed to add a single page!\n");
1716                         return -1;
1717                 }
1718                 if (submit_bio_wait(READ, bio)) {
1719                         printk(KERN_INFO
1720                                "btrfsic: read error at logical %llu dev %s!\n",
1721                                block_ctx->start, block_ctx->dev->name);
1722                         bio_put(bio);
1723                         return -1;
1724                 }
1725                 bio_put(bio);
1726                 dev_bytenr += (j - i) * PAGE_CACHE_SIZE;
1727                 i = j;
1728         }
1729         for (i = 0; i < num_pages; i++) {
1730                 block_ctx->datav[i] = kmap(block_ctx->pagev[i]);
1731                 if (!block_ctx->datav[i]) {
1732                         printk(KERN_INFO "btrfsic: kmap() failed (dev %s)!\n",
1733                                block_ctx->dev->name);
1734                         return -1;
1735                 }
1736         }
1737
1738         return block_ctx->len;
1739 }
1740
1741 static void btrfsic_dump_database(struct btrfsic_state *state)
1742 {
1743         struct list_head *elem_all;
1744
1745         BUG_ON(NULL == state);
1746
1747         printk(KERN_INFO "all_blocks_list:\n");
1748         list_for_each(elem_all, &state->all_blocks_list) {
1749                 const struct btrfsic_block *const b_all =
1750                     list_entry(elem_all, struct btrfsic_block,
1751                                all_blocks_node);
1752                 struct list_head *elem_ref_to;
1753                 struct list_head *elem_ref_from;
1754
1755                 printk(KERN_INFO "%c-block @%llu (%s/%llu/%d)\n",
1756                        btrfsic_get_block_type(state, b_all),
1757                        b_all->logical_bytenr, b_all->dev_state->name,
1758                        b_all->dev_bytenr, b_all->mirror_num);
1759
1760                 list_for_each(elem_ref_to, &b_all->ref_to_list) {
1761                         const struct btrfsic_block_link *const l =
1762                             list_entry(elem_ref_to,
1763                                        struct btrfsic_block_link,
1764                                        node_ref_to);
1765
1766                         printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1767                                " refers %u* to"
1768                                " %c @%llu (%s/%llu/%d)\n",
1769                                btrfsic_get_block_type(state, b_all),
1770                                b_all->logical_bytenr, b_all->dev_state->name,
1771                                b_all->dev_bytenr, b_all->mirror_num,
1772                                l->ref_cnt,
1773                                btrfsic_get_block_type(state, l->block_ref_to),
1774                                l->block_ref_to->logical_bytenr,
1775                                l->block_ref_to->dev_state->name,
1776                                l->block_ref_to->dev_bytenr,
1777                                l->block_ref_to->mirror_num);
1778                 }
1779
1780                 list_for_each(elem_ref_from, &b_all->ref_from_list) {
1781                         const struct btrfsic_block_link *const l =
1782                             list_entry(elem_ref_from,
1783                                        struct btrfsic_block_link,
1784                                        node_ref_from);
1785
1786                         printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1787                                " is ref %u* from"
1788                                " %c @%llu (%s/%llu/%d)\n",
1789                                btrfsic_get_block_type(state, b_all),
1790                                b_all->logical_bytenr, b_all->dev_state->name,
1791                                b_all->dev_bytenr, b_all->mirror_num,
1792                                l->ref_cnt,
1793                                btrfsic_get_block_type(state, l->block_ref_from),
1794                                l->block_ref_from->logical_bytenr,
1795                                l->block_ref_from->dev_state->name,
1796                                l->block_ref_from->dev_bytenr,
1797                                l->block_ref_from->mirror_num);
1798                 }
1799
1800                 printk(KERN_INFO "\n");
1801         }
1802 }
1803
1804 /*
1805  * Test whether the disk block contains a tree block (leaf or node)
1806  * (note that this test fails for the super block)
1807  */
1808 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
1809                                      char **datav, unsigned int num_pages)
1810 {
1811         struct btrfs_header *h;
1812         u8 csum[BTRFS_CSUM_SIZE];
1813         u32 crc = ~(u32)0;
1814         unsigned int i;
1815
1816         if (num_pages * PAGE_CACHE_SIZE < state->metablock_size)
1817                 return 1; /* not metadata */
1818         num_pages = state->metablock_size >> PAGE_CACHE_SHIFT;
1819         h = (struct btrfs_header *)datav[0];
1820
1821         if (memcmp(h->fsid, state->root->fs_info->fsid, BTRFS_UUID_SIZE))
1822                 return 1;
1823
1824         for (i = 0; i < num_pages; i++) {
1825                 u8 *data = i ? datav[i] : (datav[i] + BTRFS_CSUM_SIZE);
1826                 size_t sublen = i ? PAGE_CACHE_SIZE :
1827                                     (PAGE_CACHE_SIZE - BTRFS_CSUM_SIZE);
1828
1829                 crc = btrfs_crc32c(crc, data, sublen);
1830         }
1831         btrfs_csum_final(crc, csum);
1832         if (memcmp(csum, h->csum, state->csum_size))
1833                 return 1;
1834
1835         return 0; /* is metadata */
1836 }
1837
1838 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
1839                                           u64 dev_bytenr, char **mapped_datav,
1840                                           unsigned int num_pages,
1841                                           struct bio *bio, int *bio_is_patched,
1842                                           struct buffer_head *bh,
1843                                           int submit_bio_bh_rw)
1844 {
1845         int is_metadata;
1846         struct btrfsic_block *block;
1847         struct btrfsic_block_data_ctx block_ctx;
1848         int ret;
1849         struct btrfsic_state *state = dev_state->state;
1850         struct block_device *bdev = dev_state->bdev;
1851         unsigned int processed_len;
1852
1853         if (NULL != bio_is_patched)
1854                 *bio_is_patched = 0;
1855
1856 again:
1857         if (num_pages == 0)
1858                 return;
1859
1860         processed_len = 0;
1861         is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_datav,
1862                                                       num_pages));
1863
1864         block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
1865                                                &state->block_hashtable);
1866         if (NULL != block) {
1867                 u64 bytenr = 0;
1868                 struct list_head *elem_ref_to;
1869                 struct list_head *tmp_ref_to;
1870
1871                 if (block->is_superblock) {
1872                         bytenr = btrfs_super_bytenr((struct btrfs_super_block *)
1873                                                     mapped_datav[0]);
1874                         if (num_pages * PAGE_CACHE_SIZE <
1875                             BTRFS_SUPER_INFO_SIZE) {
1876                                 printk(KERN_INFO
1877                                        "btrfsic: cannot work with too short bios!\n");
1878                                 return;
1879                         }
1880                         is_metadata = 1;
1881                         BUG_ON(BTRFS_SUPER_INFO_SIZE & (PAGE_CACHE_SIZE - 1));
1882                         processed_len = BTRFS_SUPER_INFO_SIZE;
1883                         if (state->print_mask &
1884                             BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
1885                                 printk(KERN_INFO
1886                                        "[before new superblock is written]:\n");
1887                                 btrfsic_dump_tree_sub(state, block, 0);
1888                         }
1889                 }
1890                 if (is_metadata) {
1891                         if (!block->is_superblock) {
1892                                 if (num_pages * PAGE_CACHE_SIZE <
1893                                     state->metablock_size) {
1894                                         printk(KERN_INFO
1895                                                "btrfsic: cannot work with too short bios!\n");
1896                                         return;
1897                                 }
1898                                 processed_len = state->metablock_size;
1899                                 bytenr = btrfs_stack_header_bytenr(
1900                                                 (struct btrfs_header *)
1901                                                 mapped_datav[0]);
1902                                 btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
1903                                                                dev_state,
1904                                                                dev_bytenr);
1905                         }
1906                         if (block->logical_bytenr != bytenr &&
1907                             !(!block->is_metadata &&
1908                               block->logical_bytenr == 0))
1909                                 printk(KERN_INFO
1910                                        "Written block @%llu (%s/%llu/%d)"
1911                                        " found in hash table, %c,"
1912                                        " bytenr mismatch"
1913                                        " (!= stored %llu).\n",
1914                                        bytenr, dev_state->name, dev_bytenr,
1915                                        block->mirror_num,
1916                                        btrfsic_get_block_type(state, block),
1917                                        block->logical_bytenr);
1918                         else 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                         block->logical_bytenr = bytenr;
1926                 } else {
1927                         if (num_pages * PAGE_CACHE_SIZE <
1928                             state->datablock_size) {
1929                                 printk(KERN_INFO
1930                                        "btrfsic: cannot work with too short bios!\n");
1931                                 return;
1932                         }
1933                         processed_len = state->datablock_size;
1934                         bytenr = block->logical_bytenr;
1935                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1936                                 printk(KERN_INFO
1937                                        "Written block @%llu (%s/%llu/%d)"
1938                                        " found in hash table, %c.\n",
1939                                        bytenr, dev_state->name, dev_bytenr,
1940                                        block->mirror_num,
1941                                        btrfsic_get_block_type(state, block));
1942                 }
1943
1944                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1945                         printk(KERN_INFO
1946                                "ref_to_list: %cE, ref_from_list: %cE\n",
1947                                list_empty(&block->ref_to_list) ? ' ' : '!',
1948                                list_empty(&block->ref_from_list) ? ' ' : '!');
1949                 if (btrfsic_is_block_ref_by_superblock(state, block, 0)) {
1950                         printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
1951                                " @%llu (%s/%llu/%d), old(gen=%llu,"
1952                                " objectid=%llu, type=%d, offset=%llu),"
1953                                " new(gen=%llu),"
1954                                " which is referenced by most recent superblock"
1955                                " (superblockgen=%llu)!\n",
1956                                btrfsic_get_block_type(state, block), bytenr,
1957                                dev_state->name, dev_bytenr, block->mirror_num,
1958                                block->generation,
1959                                btrfs_disk_key_objectid(&block->disk_key),
1960                                block->disk_key.type,
1961                                btrfs_disk_key_offset(&block->disk_key),
1962                                btrfs_stack_header_generation(
1963                                        (struct btrfs_header *) mapped_datav[0]),
1964                                state->max_superblock_generation);
1965                         btrfsic_dump_tree(state);
1966                 }
1967
1968                 if (!block->is_iodone && !block->never_written) {
1969                         printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
1970                                " @%llu (%s/%llu/%d), oldgen=%llu, newgen=%llu,"
1971                                " which is not yet iodone!\n",
1972                                btrfsic_get_block_type(state, block), bytenr,
1973                                dev_state->name, dev_bytenr, block->mirror_num,
1974                                block->generation,
1975                                btrfs_stack_header_generation(
1976                                        (struct btrfs_header *)
1977                                        mapped_datav[0]));
1978                         /* it would not be safe to go on */
1979                         btrfsic_dump_tree(state);
1980                         goto continue_loop;
1981                 }
1982
1983                 /*
1984                  * Clear all references of this block. Do not free
1985                  * the block itself even if is not referenced anymore
1986                  * because it still carries valueable information
1987                  * like whether it was ever written and IO completed.
1988                  */
1989                 list_for_each_safe(elem_ref_to, tmp_ref_to,
1990                                    &block->ref_to_list) {
1991                         struct btrfsic_block_link *const l =
1992                             list_entry(elem_ref_to,
1993                                        struct btrfsic_block_link,
1994                                        node_ref_to);
1995
1996                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1997                                 btrfsic_print_rem_link(state, l);
1998                         l->ref_cnt--;
1999                         if (0 == l->ref_cnt) {
2000                                 list_del(&l->node_ref_to);
2001                                 list_del(&l->node_ref_from);
2002                                 btrfsic_block_link_hashtable_remove(l);
2003                                 btrfsic_block_link_free(l);
2004                         }
2005                 }
2006
2007                 if (block->is_superblock)
2008                         ret = btrfsic_map_superblock(state, bytenr,
2009                                                      processed_len,
2010                                                      bdev, &block_ctx);
2011                 else
2012                         ret = btrfsic_map_block(state, bytenr, processed_len,
2013                                                 &block_ctx, 0);
2014                 if (ret) {
2015                         printk(KERN_INFO
2016                                "btrfsic: btrfsic_map_block(root @%llu)"
2017                                " failed!\n", bytenr);
2018                         goto continue_loop;
2019                 }
2020                 block_ctx.datav = mapped_datav;
2021                 /* the following is required in case of writes to mirrors,
2022                  * use the same that was used for the lookup */
2023                 block_ctx.dev = dev_state;
2024                 block_ctx.dev_bytenr = dev_bytenr;
2025
2026                 if (is_metadata || state->include_extent_data) {
2027                         block->never_written = 0;
2028                         block->iodone_w_error = 0;
2029                         if (NULL != bio) {
2030                                 block->is_iodone = 0;
2031                                 BUG_ON(NULL == bio_is_patched);
2032                                 if (!*bio_is_patched) {
2033                                         block->orig_bio_bh_private =
2034                                             bio->bi_private;
2035                                         block->orig_bio_bh_end_io.bio =
2036                                             bio->bi_end_io;
2037                                         block->next_in_same_bio = NULL;
2038                                         bio->bi_private = block;
2039                                         bio->bi_end_io = btrfsic_bio_end_io;
2040                                         *bio_is_patched = 1;
2041                                 } else {
2042                                         struct btrfsic_block *chained_block =
2043                                             (struct btrfsic_block *)
2044                                             bio->bi_private;
2045
2046                                         BUG_ON(NULL == chained_block);
2047                                         block->orig_bio_bh_private =
2048                                             chained_block->orig_bio_bh_private;
2049                                         block->orig_bio_bh_end_io.bio =
2050                                             chained_block->orig_bio_bh_end_io.
2051                                             bio;
2052                                         block->next_in_same_bio = chained_block;
2053                                         bio->bi_private = block;
2054                                 }
2055                         } else if (NULL != bh) {
2056                                 block->is_iodone = 0;
2057                                 block->orig_bio_bh_private = bh->b_private;
2058                                 block->orig_bio_bh_end_io.bh = bh->b_end_io;
2059                                 block->next_in_same_bio = NULL;
2060                                 bh->b_private = block;
2061                                 bh->b_end_io = btrfsic_bh_end_io;
2062                         } else {
2063                                 block->is_iodone = 1;
2064                                 block->orig_bio_bh_private = NULL;
2065                                 block->orig_bio_bh_end_io.bio = NULL;
2066                                 block->next_in_same_bio = NULL;
2067                         }
2068                 }
2069
2070                 block->flush_gen = dev_state->last_flush_gen + 1;
2071                 block->submit_bio_bh_rw = submit_bio_bh_rw;
2072                 if (is_metadata) {
2073                         block->logical_bytenr = bytenr;
2074                         block->is_metadata = 1;
2075                         if (block->is_superblock) {
2076                                 BUG_ON(PAGE_CACHE_SIZE !=
2077                                        BTRFS_SUPER_INFO_SIZE);
2078                                 ret = btrfsic_process_written_superblock(
2079                                                 state,
2080                                                 block,
2081                                                 (struct btrfs_super_block *)
2082                                                 mapped_datav[0]);
2083                                 if (state->print_mask &
2084                                     BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE) {
2085                                         printk(KERN_INFO
2086                                         "[after new superblock is written]:\n");
2087                                         btrfsic_dump_tree_sub(state, block, 0);
2088                                 }
2089                         } else {
2090                                 block->mirror_num = 0;  /* unknown */
2091                                 ret = btrfsic_process_metablock(
2092                                                 state,
2093                                                 block,
2094                                                 &block_ctx,
2095                                                 0, 0);
2096                         }
2097                         if (ret)
2098                                 printk(KERN_INFO
2099                                        "btrfsic: btrfsic_process_metablock"
2100                                        "(root @%llu) failed!\n",
2101                                        dev_bytenr);
2102                 } else {
2103                         block->is_metadata = 0;
2104                         block->mirror_num = 0;  /* unknown */
2105                         block->generation = BTRFSIC_GENERATION_UNKNOWN;
2106                         if (!state->include_extent_data
2107                             && list_empty(&block->ref_from_list)) {
2108                                 /*
2109                                  * disk block is overwritten with extent
2110                                  * data (not meta data) and we are configured
2111                                  * to not include extent data: take the
2112                                  * chance and free the block's memory
2113                                  */
2114                                 btrfsic_block_hashtable_remove(block);
2115                                 list_del(&block->all_blocks_node);
2116                                 btrfsic_block_free(block);
2117                         }
2118                 }
2119                 btrfsic_release_block_ctx(&block_ctx);
2120         } else {
2121                 /* block has not been found in hash table */
2122                 u64 bytenr;
2123
2124                 if (!is_metadata) {
2125                         processed_len = state->datablock_size;
2126                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2127                                 printk(KERN_INFO "Written block (%s/%llu/?)"
2128                                        " !found in hash table, D.\n",
2129                                        dev_state->name, dev_bytenr);
2130                         if (!state->include_extent_data) {
2131                                 /* ignore that written D block */
2132                                 goto continue_loop;
2133                         }
2134
2135                         /* this is getting ugly for the
2136                          * include_extent_data case... */
2137                         bytenr = 0;     /* unknown */
2138                         block_ctx.start = bytenr;
2139                         block_ctx.len = processed_len;
2140                         block_ctx.mem_to_free = NULL;
2141                         block_ctx.pagev = NULL;
2142                 } else {
2143                         processed_len = state->metablock_size;
2144                         bytenr = btrfs_stack_header_bytenr(
2145                                         (struct btrfs_header *)
2146                                         mapped_datav[0]);
2147                         btrfsic_cmp_log_and_dev_bytenr(state, bytenr, dev_state,
2148                                                        dev_bytenr);
2149                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2150                                 printk(KERN_INFO
2151                                        "Written block @%llu (%s/%llu/?)"
2152                                        " !found in hash table, M.\n",
2153                                        bytenr, dev_state->name, dev_bytenr);
2154
2155                         ret = btrfsic_map_block(state, bytenr, processed_len,
2156                                                 &block_ctx, 0);
2157                         if (ret) {
2158                                 printk(KERN_INFO
2159                                        "btrfsic: btrfsic_map_block(root @%llu)"
2160                                        " failed!\n",
2161                                        dev_bytenr);
2162                                 goto continue_loop;
2163                         }
2164                 }
2165                 block_ctx.datav = mapped_datav;
2166                 /* the following is required in case of writes to mirrors,
2167                  * use the same that was used for the lookup */
2168                 block_ctx.dev = dev_state;
2169                 block_ctx.dev_bytenr = dev_bytenr;
2170
2171                 block = btrfsic_block_alloc();
2172                 if (NULL == block) {
2173                         printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2174                         btrfsic_release_block_ctx(&block_ctx);
2175                         goto continue_loop;
2176                 }
2177                 block->dev_state = dev_state;
2178                 block->dev_bytenr = dev_bytenr;
2179                 block->logical_bytenr = bytenr;
2180                 block->is_metadata = is_metadata;
2181                 block->never_written = 0;
2182                 block->iodone_w_error = 0;
2183                 block->mirror_num = 0;  /* unknown */
2184                 block->flush_gen = dev_state->last_flush_gen + 1;
2185                 block->submit_bio_bh_rw = submit_bio_bh_rw;
2186                 if (NULL != bio) {
2187                         block->is_iodone = 0;
2188                         BUG_ON(NULL == bio_is_patched);
2189                         if (!*bio_is_patched) {
2190                                 block->orig_bio_bh_private = bio->bi_private;
2191                                 block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2192                                 block->next_in_same_bio = NULL;
2193                                 bio->bi_private = block;
2194                                 bio->bi_end_io = btrfsic_bio_end_io;
2195                                 *bio_is_patched = 1;
2196                         } else {
2197                                 struct btrfsic_block *chained_block =
2198                                     (struct btrfsic_block *)
2199                                     bio->bi_private;
2200
2201                                 BUG_ON(NULL == chained_block);
2202                                 block->orig_bio_bh_private =
2203                                     chained_block->orig_bio_bh_private;
2204                                 block->orig_bio_bh_end_io.bio =
2205                                     chained_block->orig_bio_bh_end_io.bio;
2206                                 block->next_in_same_bio = chained_block;
2207                                 bio->bi_private = block;
2208                         }
2209                 } else if (NULL != bh) {
2210                         block->is_iodone = 0;
2211                         block->orig_bio_bh_private = bh->b_private;
2212                         block->orig_bio_bh_end_io.bh = bh->b_end_io;
2213                         block->next_in_same_bio = NULL;
2214                         bh->b_private = block;
2215                         bh->b_end_io = btrfsic_bh_end_io;
2216                 } else {
2217                         block->is_iodone = 1;
2218                         block->orig_bio_bh_private = NULL;
2219                         block->orig_bio_bh_end_io.bio = NULL;
2220                         block->next_in_same_bio = NULL;
2221                 }
2222                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2223                         printk(KERN_INFO
2224                                "New written %c-block @%llu (%s/%llu/%d)\n",
2225                                is_metadata ? 'M' : 'D',
2226                                block->logical_bytenr, block->dev_state->name,
2227                                block->dev_bytenr, block->mirror_num);
2228                 list_add(&block->all_blocks_node, &state->all_blocks_list);
2229                 btrfsic_block_hashtable_add(block, &state->block_hashtable);
2230
2231                 if (is_metadata) {
2232                         ret = btrfsic_process_metablock(state, block,
2233                                                         &block_ctx, 0, 0);
2234                         if (ret)
2235                                 printk(KERN_INFO
2236                                        "btrfsic: process_metablock(root @%llu)"
2237                                        " failed!\n",
2238                                        dev_bytenr);
2239                 }
2240                 btrfsic_release_block_ctx(&block_ctx);
2241         }
2242
2243 continue_loop:
2244         BUG_ON(!processed_len);
2245         dev_bytenr += processed_len;
2246         mapped_datav += processed_len >> PAGE_CACHE_SHIFT;
2247         num_pages -= processed_len >> PAGE_CACHE_SHIFT;
2248         goto again;
2249 }
2250
2251 static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status)
2252 {
2253         struct btrfsic_block *block = (struct btrfsic_block *)bp->bi_private;
2254         int iodone_w_error;
2255
2256         /* mutex is not held! This is not save if IO is not yet completed
2257          * on umount */
2258         iodone_w_error = 0;
2259         if (bio_error_status)
2260                 iodone_w_error = 1;
2261
2262         BUG_ON(NULL == block);
2263         bp->bi_private = block->orig_bio_bh_private;
2264         bp->bi_end_io = block->orig_bio_bh_end_io.bio;
2265
2266         do {
2267                 struct btrfsic_block *next_block;
2268                 struct btrfsic_dev_state *const dev_state = block->dev_state;
2269
2270                 if ((dev_state->state->print_mask &
2271                      BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2272                         printk(KERN_INFO
2273                                "bio_end_io(err=%d) for %c @%llu (%s/%llu/%d)\n",
2274                                bio_error_status,
2275                                btrfsic_get_block_type(dev_state->state, block),
2276                                block->logical_bytenr, dev_state->name,
2277                                block->dev_bytenr, block->mirror_num);
2278                 next_block = block->next_in_same_bio;
2279                 block->iodone_w_error = iodone_w_error;
2280                 if (block->submit_bio_bh_rw & REQ_FLUSH) {
2281                         dev_state->last_flush_gen++;
2282                         if ((dev_state->state->print_mask &
2283                              BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2284                                 printk(KERN_INFO
2285                                        "bio_end_io() new %s flush_gen=%llu\n",
2286                                        dev_state->name,
2287                                        dev_state->last_flush_gen);
2288                 }
2289                 if (block->submit_bio_bh_rw & REQ_FUA)
2290                         block->flush_gen = 0; /* FUA completed means block is
2291                                                * on disk */
2292                 block->is_iodone = 1; /* for FLUSH, this releases the block */
2293                 block = next_block;
2294         } while (NULL != block);
2295
2296         bp->bi_end_io(bp, bio_error_status);
2297 }
2298
2299 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate)
2300 {
2301         struct btrfsic_block *block = (struct btrfsic_block *)bh->b_private;
2302         int iodone_w_error = !uptodate;
2303         struct btrfsic_dev_state *dev_state;
2304
2305         BUG_ON(NULL == block);
2306         dev_state = block->dev_state;
2307         if ((dev_state->state->print_mask & BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2308                 printk(KERN_INFO
2309                        "bh_end_io(error=%d) for %c @%llu (%s/%llu/%d)\n",
2310                        iodone_w_error,
2311                        btrfsic_get_block_type(dev_state->state, block),
2312                        block->logical_bytenr, block->dev_state->name,
2313                        block->dev_bytenr, block->mirror_num);
2314
2315         block->iodone_w_error = iodone_w_error;
2316         if (block->submit_bio_bh_rw & REQ_FLUSH) {
2317                 dev_state->last_flush_gen++;
2318                 if ((dev_state->state->print_mask &
2319                      BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2320                         printk(KERN_INFO
2321                                "bh_end_io() new %s flush_gen=%llu\n",
2322                                dev_state->name, dev_state->last_flush_gen);
2323         }
2324         if (block->submit_bio_bh_rw & REQ_FUA)
2325                 block->flush_gen = 0; /* FUA completed means block is on disk */
2326
2327         bh->b_private = block->orig_bio_bh_private;
2328         bh->b_end_io = block->orig_bio_bh_end_io.bh;
2329         block->is_iodone = 1; /* for FLUSH, this releases the block */
2330         bh->b_end_io(bh, uptodate);
2331 }
2332
2333 static int btrfsic_process_written_superblock(
2334                 struct btrfsic_state *state,
2335                 struct btrfsic_block *const superblock,
2336                 struct btrfs_super_block *const super_hdr)
2337 {
2338         int pass;
2339
2340         superblock->generation = btrfs_super_generation(super_hdr);
2341         if (!(superblock->generation > state->max_superblock_generation ||
2342               0 == state->max_superblock_generation)) {
2343                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2344                         printk(KERN_INFO
2345                                "btrfsic: superblock @%llu (%s/%llu/%d)"
2346                                " with old gen %llu <= %llu\n",
2347                                superblock->logical_bytenr,
2348                                superblock->dev_state->name,
2349                                superblock->dev_bytenr, superblock->mirror_num,
2350                                btrfs_super_generation(super_hdr),
2351                                state->max_superblock_generation);
2352         } else {
2353                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2354                         printk(KERN_INFO
2355                                "btrfsic: got new superblock @%llu (%s/%llu/%d)"
2356                                " with new gen %llu > %llu\n",
2357                                superblock->logical_bytenr,
2358                                superblock->dev_state->name,
2359                                superblock->dev_bytenr, superblock->mirror_num,
2360                                btrfs_super_generation(super_hdr),
2361                                state->max_superblock_generation);
2362
2363                 state->max_superblock_generation =
2364                     btrfs_super_generation(super_hdr);
2365                 state->latest_superblock = superblock;
2366         }
2367
2368         for (pass = 0; pass < 3; pass++) {
2369                 int ret;
2370                 u64 next_bytenr;
2371                 struct btrfsic_block *next_block;
2372                 struct btrfsic_block_data_ctx tmp_next_block_ctx;
2373                 struct btrfsic_block_link *l;
2374                 int num_copies;
2375                 int mirror_num;
2376                 const char *additional_string = NULL;
2377                 struct btrfs_disk_key tmp_disk_key = {0};
2378
2379                 btrfs_set_disk_key_objectid(&tmp_disk_key,
2380                                             BTRFS_ROOT_ITEM_KEY);
2381                 btrfs_set_disk_key_objectid(&tmp_disk_key, 0);
2382
2383                 switch (pass) {
2384                 case 0:
2385                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2386                                                     BTRFS_ROOT_TREE_OBJECTID);
2387                         additional_string = "root ";
2388                         next_bytenr = btrfs_super_root(super_hdr);
2389                         if (state->print_mask &
2390                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2391                                 printk(KERN_INFO "root@%llu\n", next_bytenr);
2392                         break;
2393                 case 1:
2394                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2395                                                     BTRFS_CHUNK_TREE_OBJECTID);
2396                         additional_string = "chunk ";
2397                         next_bytenr = btrfs_super_chunk_root(super_hdr);
2398                         if (state->print_mask &
2399                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2400                                 printk(KERN_INFO "chunk@%llu\n", next_bytenr);
2401                         break;
2402                 case 2:
2403                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2404                                                     BTRFS_TREE_LOG_OBJECTID);
2405                         additional_string = "log ";
2406                         next_bytenr = btrfs_super_log_root(super_hdr);
2407                         if (0 == next_bytenr)
2408                                 continue;
2409                         if (state->print_mask &
2410                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2411                                 printk(KERN_INFO "log@%llu\n", next_bytenr);
2412                         break;
2413                 }
2414
2415                 num_copies =
2416                     btrfs_num_copies(state->root->fs_info,
2417                                      next_bytenr, BTRFS_SUPER_INFO_SIZE);
2418                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
2419                         printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
2420                                next_bytenr, num_copies);
2421                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2422                         int was_created;
2423
2424                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2425                                 printk(KERN_INFO
2426                                        "btrfsic_process_written_superblock("
2427                                        "mirror_num=%d)\n", mirror_num);
2428                         ret = btrfsic_map_block(state, next_bytenr,
2429                                                 BTRFS_SUPER_INFO_SIZE,
2430                                                 &tmp_next_block_ctx,
2431                                                 mirror_num);
2432                         if (ret) {
2433                                 printk(KERN_INFO
2434                                        "btrfsic: btrfsic_map_block(@%llu,"
2435                                        " mirror=%d) failed!\n",
2436                                        next_bytenr, mirror_num);
2437                                 return -1;
2438                         }
2439
2440                         next_block = btrfsic_block_lookup_or_add(
2441                                         state,
2442                                         &tmp_next_block_ctx,
2443                                         additional_string,
2444                                         1, 0, 1,
2445                                         mirror_num,
2446                                         &was_created);
2447                         if (NULL == next_block) {
2448                                 printk(KERN_INFO
2449                                        "btrfsic: error, kmalloc failed!\n");
2450                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
2451                                 return -1;
2452                         }
2453
2454                         next_block->disk_key = tmp_disk_key;
2455                         if (was_created)
2456                                 next_block->generation =
2457                                     BTRFSIC_GENERATION_UNKNOWN;
2458                         l = btrfsic_block_link_lookup_or_add(
2459                                         state,
2460                                         &tmp_next_block_ctx,
2461                                         next_block,
2462                                         superblock,
2463                                         BTRFSIC_GENERATION_UNKNOWN);
2464                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
2465                         if (NULL == l)
2466                                 return -1;
2467                 }
2468         }
2469
2470         if (WARN_ON(-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)))
2471                 btrfsic_dump_tree(state);
2472
2473         return 0;
2474 }
2475
2476 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
2477                                         struct btrfsic_block *const block,
2478                                         int recursion_level)
2479 {
2480         struct list_head *elem_ref_to;
2481         int ret = 0;
2482
2483         if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2484                 /*
2485                  * Note that this situation can happen and does not
2486                  * indicate an error in regular cases. It happens
2487                  * when disk blocks are freed and later reused.
2488                  * The check-integrity module is not aware of any
2489                  * block free operations, it just recognizes block
2490                  * write operations. Therefore it keeps the linkage
2491                  * information for a block until a block is
2492                  * rewritten. This can temporarily cause incorrect
2493                  * and even circular linkage informations. This
2494                  * causes no harm unless such blocks are referenced
2495                  * by the most recent super block.
2496                  */
2497                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2498                         printk(KERN_INFO
2499                                "btrfsic: abort cyclic linkage (case 1).\n");
2500
2501                 return ret;
2502         }
2503
2504         /*
2505          * This algorithm is recursive because the amount of used stack
2506          * space is very small and the max recursion depth is limited.
2507          */
2508         list_for_each(elem_ref_to, &block->ref_to_list) {
2509                 const struct btrfsic_block_link *const l =
2510                     list_entry(elem_ref_to, struct btrfsic_block_link,
2511                                node_ref_to);
2512
2513                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2514                         printk(KERN_INFO
2515                                "rl=%d, %c @%llu (%s/%llu/%d)"
2516                                " %u* refers to %c @%llu (%s/%llu/%d)\n",
2517                                recursion_level,
2518                                btrfsic_get_block_type(state, block),
2519                                block->logical_bytenr, block->dev_state->name,
2520                                block->dev_bytenr, block->mirror_num,
2521                                l->ref_cnt,
2522                                btrfsic_get_block_type(state, l->block_ref_to),
2523                                l->block_ref_to->logical_bytenr,
2524                                l->block_ref_to->dev_state->name,
2525                                l->block_ref_to->dev_bytenr,
2526                                l->block_ref_to->mirror_num);
2527                 if (l->block_ref_to->never_written) {
2528                         printk(KERN_INFO "btrfs: attempt to write superblock"
2529                                " which references block %c @%llu (%s/%llu/%d)"
2530                                " which is never written!\n",
2531                                btrfsic_get_block_type(state, l->block_ref_to),
2532                                l->block_ref_to->logical_bytenr,
2533                                l->block_ref_to->dev_state->name,
2534                                l->block_ref_to->dev_bytenr,
2535                                l->block_ref_to->mirror_num);
2536                         ret = -1;
2537                 } else if (!l->block_ref_to->is_iodone) {
2538                         printk(KERN_INFO "btrfs: attempt to write superblock"
2539                                " which references block %c @%llu (%s/%llu/%d)"
2540                                " which is not yet iodone!\n",
2541                                btrfsic_get_block_type(state, l->block_ref_to),
2542                                l->block_ref_to->logical_bytenr,
2543                                l->block_ref_to->dev_state->name,
2544                                l->block_ref_to->dev_bytenr,
2545                                l->block_ref_to->mirror_num);
2546                         ret = -1;
2547                 } else if (l->block_ref_to->iodone_w_error) {
2548                         printk(KERN_INFO "btrfs: attempt to write superblock"
2549                                " which references block %c @%llu (%s/%llu/%d)"
2550                                " which has write error!\n",
2551                                btrfsic_get_block_type(state, l->block_ref_to),
2552                                l->block_ref_to->logical_bytenr,
2553                                l->block_ref_to->dev_state->name,
2554                                l->block_ref_to->dev_bytenr,
2555                                l->block_ref_to->mirror_num);
2556                         ret = -1;
2557                 } else if (l->parent_generation !=
2558                            l->block_ref_to->generation &&
2559                            BTRFSIC_GENERATION_UNKNOWN !=
2560                            l->parent_generation &&
2561                            BTRFSIC_GENERATION_UNKNOWN !=
2562                            l->block_ref_to->generation) {
2563                         printk(KERN_INFO "btrfs: attempt to write superblock"
2564                                " which references block %c @%llu (%s/%llu/%d)"
2565                                " with generation %llu !="
2566                                " parent generation %llu!\n",
2567                                btrfsic_get_block_type(state, l->block_ref_to),
2568                                l->block_ref_to->logical_bytenr,
2569                                l->block_ref_to->dev_state->name,
2570                                l->block_ref_to->dev_bytenr,
2571                                l->block_ref_to->mirror_num,
2572                                l->block_ref_to->generation,
2573                                l->parent_generation);
2574                         ret = -1;
2575                 } else if (l->block_ref_to->flush_gen >
2576                            l->block_ref_to->dev_state->last_flush_gen) {
2577                         printk(KERN_INFO "btrfs: attempt to write superblock"
2578                                " which references block %c @%llu (%s/%llu/%d)"
2579                                " which is not flushed out of disk's write cache"
2580                                " (block flush_gen=%llu,"
2581                                " dev->flush_gen=%llu)!\n",
2582                                btrfsic_get_block_type(state, l->block_ref_to),
2583                                l->block_ref_to->logical_bytenr,
2584                                l->block_ref_to->dev_state->name,
2585                                l->block_ref_to->dev_bytenr,
2586                                l->block_ref_to->mirror_num, block->flush_gen,
2587                                l->block_ref_to->dev_state->last_flush_gen);
2588                         ret = -1;
2589                 } else if (-1 == btrfsic_check_all_ref_blocks(state,
2590                                                               l->block_ref_to,
2591                                                               recursion_level +
2592                                                               1)) {
2593                         ret = -1;
2594                 }
2595         }
2596
2597         return ret;
2598 }
2599
2600 static int btrfsic_is_block_ref_by_superblock(
2601                 const struct btrfsic_state *state,
2602                 const struct btrfsic_block *block,
2603                 int recursion_level)
2604 {
2605         struct list_head *elem_ref_from;
2606
2607         if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2608                 /* refer to comment at "abort cyclic linkage (case 1)" */
2609                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2610                         printk(KERN_INFO
2611                                "btrfsic: abort cyclic linkage (case 2).\n");
2612
2613                 return 0;
2614         }
2615
2616         /*
2617          * This algorithm is recursive because the amount of used stack space
2618          * is very small and the max recursion depth is limited.
2619          */
2620         list_for_each(elem_ref_from, &block->ref_from_list) {
2621                 const struct btrfsic_block_link *const l =
2622                     list_entry(elem_ref_from, struct btrfsic_block_link,
2623                                node_ref_from);
2624
2625                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2626                         printk(KERN_INFO
2627                                "rl=%d, %c @%llu (%s/%llu/%d)"
2628                                " is ref %u* from %c @%llu (%s/%llu/%d)\n",
2629                                recursion_level,
2630                                btrfsic_get_block_type(state, block),
2631                                block->logical_bytenr, block->dev_state->name,
2632                                block->dev_bytenr, block->mirror_num,
2633                                l->ref_cnt,
2634                                btrfsic_get_block_type(state, l->block_ref_from),
2635                                l->block_ref_from->logical_bytenr,
2636                                l->block_ref_from->dev_state->name,
2637                                l->block_ref_from->dev_bytenr,
2638                                l->block_ref_from->mirror_num);
2639                 if (l->block_ref_from->is_superblock &&
2640                     state->latest_superblock->dev_bytenr ==
2641                     l->block_ref_from->dev_bytenr &&
2642                     state->latest_superblock->dev_state->bdev ==
2643                     l->block_ref_from->dev_state->bdev)
2644                         return 1;
2645                 else if (btrfsic_is_block_ref_by_superblock(state,
2646                                                             l->block_ref_from,
2647                                                             recursion_level +
2648                                                             1))
2649                         return 1;
2650         }
2651
2652         return 0;
2653 }
2654
2655 static void btrfsic_print_add_link(const struct btrfsic_state *state,
2656                                    const struct btrfsic_block_link *l)
2657 {
2658         printk(KERN_INFO
2659                "Add %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 void btrfsic_print_rem_link(const struct btrfsic_state *state,
2673                                    const struct btrfsic_block_link *l)
2674 {
2675         printk(KERN_INFO
2676                "Rem %u* link from %c @%llu (%s/%llu/%d)"
2677                " to %c @%llu (%s/%llu/%d).\n",
2678                l->ref_cnt,
2679                btrfsic_get_block_type(state, l->block_ref_from),
2680                l->block_ref_from->logical_bytenr,
2681                l->block_ref_from->dev_state->name,
2682                l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2683                btrfsic_get_block_type(state, l->block_ref_to),
2684                l->block_ref_to->logical_bytenr,
2685                l->block_ref_to->dev_state->name, l->block_ref_to->dev_bytenr,
2686                l->block_ref_to->mirror_num);
2687 }
2688
2689 static char btrfsic_get_block_type(const struct btrfsic_state *state,
2690                                    const struct btrfsic_block *block)
2691 {
2692         if (block->is_superblock &&
2693             state->latest_superblock->dev_bytenr == block->dev_bytenr &&
2694             state->latest_superblock->dev_state->bdev == block->dev_state->bdev)
2695                 return 'S';
2696         else if (block->is_superblock)
2697                 return 's';
2698         else if (block->is_metadata)
2699                 return 'M';
2700         else
2701                 return 'D';
2702 }
2703
2704 static void btrfsic_dump_tree(const struct btrfsic_state *state)
2705 {
2706         btrfsic_dump_tree_sub(state, state->latest_superblock, 0);
2707 }
2708
2709 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
2710                                   const struct btrfsic_block *block,
2711                                   int indent_level)
2712 {
2713         struct list_head *elem_ref_to;
2714         int indent_add;
2715         static char buf[80];
2716         int cursor_position;
2717
2718         /*
2719          * Should better fill an on-stack buffer with a complete line and
2720          * dump it at once when it is time to print a newline character.
2721          */
2722
2723         /*
2724          * This algorithm is recursive because the amount of used stack space
2725          * is very small and the max recursion depth is limited.
2726          */
2727         indent_add = sprintf(buf, "%c-%llu(%s/%llu/%d)",
2728                              btrfsic_get_block_type(state, block),
2729                              block->logical_bytenr, block->dev_state->name,
2730                              block->dev_bytenr, block->mirror_num);
2731         if (indent_level + indent_add > BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2732                 printk("[...]\n");
2733                 return;
2734         }
2735         printk(buf);
2736         indent_level += indent_add;
2737         if (list_empty(&block->ref_to_list)) {
2738                 printk("\n");
2739                 return;
2740         }
2741         if (block->mirror_num > 1 &&
2742             !(state->print_mask & BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS)) {
2743                 printk(" [...]\n");
2744                 return;
2745         }
2746
2747         cursor_position = indent_level;
2748         list_for_each(elem_ref_to, &block->ref_to_list) {
2749                 const struct btrfsic_block_link *const l =
2750                     list_entry(elem_ref_to, struct btrfsic_block_link,
2751                                node_ref_to);
2752
2753                 while (cursor_position < indent_level) {
2754                         printk(" ");
2755                         cursor_position++;
2756                 }
2757                 if (l->ref_cnt > 1)
2758                         indent_add = sprintf(buf, " %d*--> ", l->ref_cnt);
2759                 else
2760                         indent_add = sprintf(buf, " --> ");
2761                 if (indent_level + indent_add >
2762                     BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2763                         printk("[...]\n");
2764                         cursor_position = 0;
2765                         continue;
2766                 }
2767
2768                 printk(buf);
2769
2770                 btrfsic_dump_tree_sub(state, l->block_ref_to,
2771                                       indent_level + indent_add);
2772                 cursor_position = 0;
2773         }
2774 }
2775
2776 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
2777                 struct btrfsic_state *state,
2778                 struct btrfsic_block_data_ctx *next_block_ctx,
2779                 struct btrfsic_block *next_block,
2780                 struct btrfsic_block *from_block,
2781                 u64 parent_generation)
2782 {
2783         struct btrfsic_block_link *l;
2784
2785         l = btrfsic_block_link_hashtable_lookup(next_block_ctx->dev->bdev,
2786                                                 next_block_ctx->dev_bytenr,
2787                                                 from_block->dev_state->bdev,
2788                                                 from_block->dev_bytenr,
2789                                                 &state->block_link_hashtable);
2790         if (NULL == l) {
2791                 l = btrfsic_block_link_alloc();
2792                 if (NULL == l) {
2793                         printk(KERN_INFO
2794                                "btrfsic: error, kmalloc" " failed!\n");
2795                         return NULL;
2796                 }
2797
2798                 l->block_ref_to = next_block;
2799                 l->block_ref_from = from_block;
2800                 l->ref_cnt = 1;
2801                 l->parent_generation = parent_generation;
2802
2803                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2804                         btrfsic_print_add_link(state, l);
2805
2806                 list_add(&l->node_ref_to, &from_block->ref_to_list);
2807                 list_add(&l->node_ref_from, &next_block->ref_from_list);
2808
2809                 btrfsic_block_link_hashtable_add(l,
2810                                                  &state->block_link_hashtable);
2811         } else {
2812                 l->ref_cnt++;
2813                 l->parent_generation = parent_generation;
2814                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2815                         btrfsic_print_add_link(state, l);
2816         }
2817
2818         return l;
2819 }
2820
2821 static struct btrfsic_block *btrfsic_block_lookup_or_add(
2822                 struct btrfsic_state *state,
2823                 struct btrfsic_block_data_ctx *block_ctx,
2824                 const char *additional_string,
2825                 int is_metadata,
2826                 int is_iodone,
2827                 int never_written,
2828                 int mirror_num,
2829                 int *was_created)
2830 {
2831         struct btrfsic_block *block;
2832
2833         block = btrfsic_block_hashtable_lookup(block_ctx->dev->bdev,
2834                                                block_ctx->dev_bytenr,
2835                                                &state->block_hashtable);
2836         if (NULL == block) {
2837                 struct btrfsic_dev_state *dev_state;
2838
2839                 block = btrfsic_block_alloc();
2840                 if (NULL == block) {
2841                         printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2842                         return NULL;
2843                 }
2844                 dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev);
2845                 if (NULL == dev_state) {
2846                         printk(KERN_INFO
2847                                "btrfsic: error, lookup dev_state failed!\n");
2848                         btrfsic_block_free(block);
2849                         return NULL;
2850                 }
2851                 block->dev_state = dev_state;
2852                 block->dev_bytenr = block_ctx->dev_bytenr;
2853                 block->logical_bytenr = block_ctx->start;
2854                 block->is_metadata = is_metadata;
2855                 block->is_iodone = is_iodone;
2856                 block->never_written = never_written;
2857                 block->mirror_num = mirror_num;
2858                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2859                         printk(KERN_INFO
2860                                "New %s%c-block @%llu (%s/%llu/%d)\n",
2861                                additional_string,
2862                                btrfsic_get_block_type(state, block),
2863                                block->logical_bytenr, dev_state->name,
2864                                block->dev_bytenr, mirror_num);
2865                 list_add(&block->all_blocks_node, &state->all_blocks_list);
2866                 btrfsic_block_hashtable_add(block, &state->block_hashtable);
2867                 if (NULL != was_created)
2868                         *was_created = 1;
2869         } else {
2870                 if (NULL != was_created)
2871                         *was_created = 0;
2872         }
2873
2874         return block;
2875 }
2876
2877 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
2878                                            u64 bytenr,
2879                                            struct btrfsic_dev_state *dev_state,
2880                                            u64 dev_bytenr)
2881 {
2882         int num_copies;
2883         int mirror_num;
2884         int ret;
2885         struct btrfsic_block_data_ctx block_ctx;
2886         int match = 0;
2887
2888         num_copies = btrfs_num_copies(state->root->fs_info,
2889                                       bytenr, state->metablock_size);
2890
2891         for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2892                 ret = btrfsic_map_block(state, bytenr, state->metablock_size,
2893                                         &block_ctx, mirror_num);
2894                 if (ret) {
2895                         printk(KERN_INFO "btrfsic:"
2896                                " btrfsic_map_block(logical @%llu,"
2897                                " mirror %d) failed!\n",
2898                                bytenr, mirror_num);
2899                         continue;
2900                 }
2901
2902                 if (dev_state->bdev == block_ctx.dev->bdev &&
2903                     dev_bytenr == block_ctx.dev_bytenr) {
2904                         match++;
2905                         btrfsic_release_block_ctx(&block_ctx);
2906                         break;
2907                 }
2908                 btrfsic_release_block_ctx(&block_ctx);
2909         }
2910
2911         if (WARN_ON(!match)) {
2912                 printk(KERN_INFO "btrfs: attempt to write M-block which contains logical bytenr that doesn't map to dev+physical bytenr of submit_bio,"
2913                        " buffer->log_bytenr=%llu, submit_bio(bdev=%s,"
2914                        " phys_bytenr=%llu)!\n",
2915                        bytenr, dev_state->name, dev_bytenr);
2916                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2917                         ret = btrfsic_map_block(state, bytenr,
2918                                                 state->metablock_size,
2919                                                 &block_ctx, mirror_num);
2920                         if (ret)
2921                                 continue;
2922
2923                         printk(KERN_INFO "Read logical bytenr @%llu maps to"
2924                                " (%s/%llu/%d)\n",
2925                                bytenr, block_ctx.dev->name,
2926                                block_ctx.dev_bytenr, mirror_num);
2927                 }
2928         }
2929 }
2930
2931 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
2932                 struct block_device *bdev)
2933 {
2934         struct btrfsic_dev_state *ds;
2935
2936         ds = btrfsic_dev_state_hashtable_lookup(bdev,
2937                                                 &btrfsic_dev_state_hashtable);
2938         return ds;
2939 }
2940
2941 int btrfsic_submit_bh(int rw, struct buffer_head *bh)
2942 {
2943         struct btrfsic_dev_state *dev_state;
2944
2945         if (!btrfsic_is_initialized)
2946                 return submit_bh(rw, bh);
2947
2948         mutex_lock(&btrfsic_mutex);
2949         /* since btrfsic_submit_bh() might also be called before
2950          * btrfsic_mount(), this might return NULL */
2951         dev_state = btrfsic_dev_state_lookup(bh->b_bdev);
2952
2953         /* Only called to write the superblock (incl. FLUSH/FUA) */
2954         if (NULL != dev_state &&
2955             (rw & WRITE) && bh->b_size > 0) {
2956                 u64 dev_bytenr;
2957
2958                 dev_bytenr = 4096 * bh->b_blocknr;
2959                 if (dev_state->state->print_mask &
2960                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2961                         printk(KERN_INFO
2962                                "submit_bh(rw=0x%x, blocknr=%llu (bytenr %llu),"
2963                                " size=%zu, data=%p, bdev=%p)\n",
2964                                rw, (unsigned long long)bh->b_blocknr,
2965                                dev_bytenr, bh->b_size, bh->b_data, bh->b_bdev);
2966                 btrfsic_process_written_block(dev_state, dev_bytenr,
2967                                               &bh->b_data, 1, NULL,
2968                                               NULL, bh, rw);
2969         } else if (NULL != dev_state && (rw & REQ_FLUSH)) {
2970                 if (dev_state->state->print_mask &
2971                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2972                         printk(KERN_INFO
2973                                "submit_bh(rw=0x%x FLUSH, bdev=%p)\n",
2974                                rw, bh->b_bdev);
2975                 if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
2976                         if ((dev_state->state->print_mask &
2977                              (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2978                               BTRFSIC_PRINT_MASK_VERBOSE)))
2979                                 printk(KERN_INFO
2980                                        "btrfsic_submit_bh(%s) with FLUSH"
2981                                        " but dummy block already in use"
2982                                        " (ignored)!\n",
2983                                        dev_state->name);
2984                 } else {
2985                         struct btrfsic_block *const block =
2986                                 &dev_state->dummy_block_for_bio_bh_flush;
2987
2988                         block->is_iodone = 0;
2989                         block->never_written = 0;
2990                         block->iodone_w_error = 0;
2991                         block->flush_gen = dev_state->last_flush_gen + 1;
2992                         block->submit_bio_bh_rw = rw;
2993                         block->orig_bio_bh_private = bh->b_private;
2994                         block->orig_bio_bh_end_io.bh = bh->b_end_io;
2995                         block->next_in_same_bio = NULL;
2996                         bh->b_private = block;
2997                         bh->b_end_io = btrfsic_bh_end_io;
2998                 }
2999         }
3000         mutex_unlock(&btrfsic_mutex);
3001         return submit_bh(rw, bh);
3002 }
3003
3004 static void __btrfsic_submit_bio(int rw, struct bio *bio)
3005 {
3006         struct btrfsic_dev_state *dev_state;
3007
3008         if (!btrfsic_is_initialized)
3009                 return;
3010
3011         mutex_lock(&btrfsic_mutex);
3012         /* since btrfsic_submit_bio() is also called before
3013          * btrfsic_mount(), this might return NULL */
3014         dev_state = btrfsic_dev_state_lookup(bio->bi_bdev);
3015         if (NULL != dev_state &&
3016             (rw & WRITE) && NULL != bio->bi_io_vec) {
3017                 unsigned int i;
3018                 u64 dev_bytenr;
3019                 u64 cur_bytenr;
3020                 int bio_is_patched;
3021                 char **mapped_datav;
3022
3023                 dev_bytenr = 512 * bio->bi_iter.bi_sector;
3024                 bio_is_patched = 0;
3025                 if (dev_state->state->print_mask &
3026                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3027                         printk(KERN_INFO
3028                                "submit_bio(rw=0x%x, bi_vcnt=%u,"
3029                                " bi_sector=%llu (bytenr %llu), bi_bdev=%p)\n",
3030                                rw, bio->bi_vcnt,
3031                                (unsigned long long)bio->bi_iter.bi_sector,
3032                                dev_bytenr, bio->bi_bdev);
3033
3034                 mapped_datav = kmalloc(sizeof(*mapped_datav) * bio->bi_vcnt,
3035                                        GFP_NOFS);
3036                 if (!mapped_datav)
3037                         goto leave;
3038                 cur_bytenr = dev_bytenr;
3039                 for (i = 0; i < bio->bi_vcnt; i++) {
3040                         BUG_ON(bio->bi_io_vec[i].bv_len != PAGE_CACHE_SIZE);
3041                         mapped_datav[i] = kmap(bio->bi_io_vec[i].bv_page);
3042                         if (!mapped_datav[i]) {
3043                                 while (i > 0) {
3044                                         i--;
3045                                         kunmap(bio->bi_io_vec[i].bv_page);
3046                                 }
3047                                 kfree(mapped_datav);
3048                                 goto leave;
3049                         }
3050                         if (dev_state->state->print_mask &
3051                             BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE)
3052                                 printk(KERN_INFO
3053                                        "#%u: bytenr=%llu, len=%u, offset=%u\n",
3054                                        i, cur_bytenr, bio->bi_io_vec[i].bv_len,
3055                                        bio->bi_io_vec[i].bv_offset);
3056                         cur_bytenr += bio->bi_io_vec[i].bv_len;
3057                 }
3058                 btrfsic_process_written_block(dev_state, dev_bytenr,
3059                                               mapped_datav, bio->bi_vcnt,
3060                                               bio, &bio_is_patched,
3061                                               NULL, rw);
3062                 while (i > 0) {
3063                         i--;
3064                         kunmap(bio->bi_io_vec[i].bv_page);
3065                 }
3066                 kfree(mapped_datav);
3067         } else if (NULL != dev_state && (rw & REQ_FLUSH)) {
3068                 if (dev_state->state->print_mask &
3069                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3070                         printk(KERN_INFO
3071                                "submit_bio(rw=0x%x FLUSH, bdev=%p)\n",
3072                                rw, bio->bi_bdev);
3073                 if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
3074                         if ((dev_state->state->print_mask &
3075                              (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3076                               BTRFSIC_PRINT_MASK_VERBOSE)))
3077                                 printk(KERN_INFO
3078                                        "btrfsic_submit_bio(%s) with FLUSH"
3079                                        " but dummy block already in use"
3080                                        " (ignored)!\n",
3081                                        dev_state->name);
3082                 } else {
3083                         struct btrfsic_block *const block =
3084                                 &dev_state->dummy_block_for_bio_bh_flush;
3085
3086                         block->is_iodone = 0;
3087                         block->never_written = 0;
3088                         block->iodone_w_error = 0;
3089                         block->flush_gen = dev_state->last_flush_gen + 1;
3090                         block->submit_bio_bh_rw = rw;
3091                         block->orig_bio_bh_private = bio->bi_private;
3092                         block->orig_bio_bh_end_io.bio = bio->bi_end_io;
3093                         block->next_in_same_bio = NULL;
3094                         bio->bi_private = block;
3095                         bio->bi_end_io = btrfsic_bio_end_io;
3096                 }
3097         }
3098 leave:
3099         mutex_unlock(&btrfsic_mutex);
3100 }
3101
3102 void btrfsic_submit_bio(int rw, struct bio *bio)
3103 {
3104         __btrfsic_submit_bio(rw, bio);
3105         submit_bio(rw, bio);
3106 }
3107
3108 int btrfsic_submit_bio_wait(int rw, struct bio *bio)
3109 {
3110         __btrfsic_submit_bio(rw, bio);
3111         return submit_bio_wait(rw, bio);
3112 }
3113
3114 int btrfsic_mount(struct btrfs_root *root,
3115                   struct btrfs_fs_devices *fs_devices,
3116                   int including_extent_data, u32 print_mask)
3117 {
3118         int ret;
3119         struct btrfsic_state *state;
3120         struct list_head *dev_head = &fs_devices->devices;
3121         struct btrfs_device *device;
3122
3123         if (root->nodesize != root->leafsize) {
3124                 printk(KERN_INFO
3125                        "btrfsic: cannot handle nodesize %d != leafsize %d!\n",
3126                        root->nodesize, root->leafsize);
3127                 return -1;
3128         }
3129         if (root->nodesize & ((u64)PAGE_CACHE_SIZE - 1)) {
3130                 printk(KERN_INFO
3131                        "btrfsic: cannot handle nodesize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3132                        root->nodesize, PAGE_CACHE_SIZE);
3133                 return -1;
3134         }
3135         if (root->leafsize & ((u64)PAGE_CACHE_SIZE - 1)) {
3136                 printk(KERN_INFO
3137                        "btrfsic: cannot handle leafsize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3138                        root->leafsize, PAGE_CACHE_SIZE);
3139                 return -1;
3140         }
3141         if (root->sectorsize & ((u64)PAGE_CACHE_SIZE - 1)) {
3142                 printk(KERN_INFO
3143                        "btrfsic: cannot handle sectorsize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3144                        root->sectorsize, PAGE_CACHE_SIZE);
3145                 return -1;
3146         }
3147         state = kzalloc(sizeof(*state), GFP_NOFS);
3148         if (NULL == state) {
3149                 printk(KERN_INFO "btrfs check-integrity: kmalloc() failed!\n");
3150                 return -1;
3151         }
3152
3153         if (!btrfsic_is_initialized) {
3154                 mutex_init(&btrfsic_mutex);
3155                 btrfsic_dev_state_hashtable_init(&btrfsic_dev_state_hashtable);
3156                 btrfsic_is_initialized = 1;
3157         }
3158         mutex_lock(&btrfsic_mutex);
3159         state->root = root;
3160         state->print_mask = print_mask;
3161         state->include_extent_data = including_extent_data;
3162         state->csum_size = 0;
3163         state->metablock_size = root->nodesize;
3164         state->datablock_size = root->sectorsize;
3165         INIT_LIST_HEAD(&state->all_blocks_list);
3166         btrfsic_block_hashtable_init(&state->block_hashtable);
3167         btrfsic_block_link_hashtable_init(&state->block_link_hashtable);
3168         state->max_superblock_generation = 0;
3169         state->latest_superblock = NULL;
3170
3171         list_for_each_entry(device, dev_head, dev_list) {
3172                 struct btrfsic_dev_state *ds;
3173                 char *p;
3174
3175                 if (!device->bdev || !device->name)
3176                         continue;
3177
3178                 ds = btrfsic_dev_state_alloc();
3179                 if (NULL == ds) {
3180                         printk(KERN_INFO
3181                                "btrfs check-integrity: kmalloc() failed!\n");
3182                         mutex_unlock(&btrfsic_mutex);
3183                         return -1;
3184                 }
3185                 ds->bdev = device->bdev;
3186                 ds->state = state;
3187                 bdevname(ds->bdev, ds->name);
3188                 ds->name[BDEVNAME_SIZE - 1] = '\0';
3189                 for (p = ds->name; *p != '\0'; p++);
3190                 while (p > ds->name && *p != '/')
3191                         p--;
3192                 if (*p == '/')
3193                         p++;
3194                 strlcpy(ds->name, p, sizeof(ds->name));
3195                 btrfsic_dev_state_hashtable_add(ds,
3196                                                 &btrfsic_dev_state_hashtable);
3197         }
3198
3199         ret = btrfsic_process_superblock(state, fs_devices);
3200         if (0 != ret) {
3201                 mutex_unlock(&btrfsic_mutex);
3202                 btrfsic_unmount(root, fs_devices);
3203                 return ret;
3204         }
3205
3206         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_DATABASE)
3207                 btrfsic_dump_database(state);
3208         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_TREE)
3209                 btrfsic_dump_tree(state);
3210
3211         mutex_unlock(&btrfsic_mutex);
3212         return 0;
3213 }
3214
3215 void btrfsic_unmount(struct btrfs_root *root,
3216                      struct btrfs_fs_devices *fs_devices)
3217 {
3218         struct list_head *elem_all;
3219         struct list_head *tmp_all;
3220         struct btrfsic_state *state;
3221         struct list_head *dev_head = &fs_devices->devices;
3222         struct btrfs_device *device;
3223
3224         if (!btrfsic_is_initialized)
3225                 return;
3226
3227         mutex_lock(&btrfsic_mutex);
3228
3229         state = NULL;
3230         list_for_each_entry(device, dev_head, dev_list) {
3231                 struct btrfsic_dev_state *ds;
3232
3233                 if (!device->bdev || !device->name)
3234                         continue;
3235
3236                 ds = btrfsic_dev_state_hashtable_lookup(
3237                                 device->bdev,
3238                                 &btrfsic_dev_state_hashtable);
3239                 if (NULL != ds) {
3240                         state = ds->state;
3241                         btrfsic_dev_state_hashtable_remove(ds);
3242                         btrfsic_dev_state_free(ds);
3243                 }
3244         }
3245
3246         if (NULL == state) {
3247                 printk(KERN_INFO
3248                        "btrfsic: error, cannot find state information"
3249                        " on umount!\n");
3250                 mutex_unlock(&btrfsic_mutex);
3251                 return;
3252         }
3253
3254         /*
3255          * Don't care about keeping the lists' state up to date,
3256          * just free all memory that was allocated dynamically.
3257          * Free the blocks and the block_links.
3258          */
3259         list_for_each_safe(elem_all, tmp_all, &state->all_blocks_list) {
3260                 struct btrfsic_block *const b_all =
3261                     list_entry(elem_all, struct btrfsic_block,
3262                                all_blocks_node);
3263                 struct list_head *elem_ref_to;
3264                 struct list_head *tmp_ref_to;
3265
3266                 list_for_each_safe(elem_ref_to, tmp_ref_to,
3267                                    &b_all->ref_to_list) {
3268                         struct btrfsic_block_link *const l =
3269                             list_entry(elem_ref_to,
3270                                        struct btrfsic_block_link,
3271                                        node_ref_to);
3272
3273                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
3274                                 btrfsic_print_rem_link(state, l);
3275
3276                         l->ref_cnt--;
3277                         if (0 == l->ref_cnt)
3278                                 btrfsic_block_link_free(l);
3279                 }
3280
3281                 if (b_all->is_iodone || b_all->never_written)
3282                         btrfsic_block_free(b_all);
3283                 else
3284                         printk(KERN_INFO "btrfs: attempt to free %c-block"
3285                                " @%llu (%s/%llu/%d) on umount which is"
3286                                " not yet iodone!\n",
3287                                btrfsic_get_block_type(state, b_all),
3288                                b_all->logical_bytenr, b_all->dev_state->name,
3289                                b_all->dev_bytenr, b_all->mirror_num);
3290         }
3291
3292         mutex_unlock(&btrfsic_mutex);
3293
3294         kfree(state);
3295 }