kernel/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 <linux/vmalloc.h>
  98 #include "ctree.h"
  99 #include "disk-io.h"
 100 #include "hash.h"
 101 #include "transaction.h"
 102 #include "extent_io.h"
 103 #include "volumes.h"
 104 #include "print-tree.h"
 105 #include "locking.h"
 106 #include "check-integrity.h"
 107 #include "rcu-string.h"
 108
 109 #define BTRFSIC_BLOCK_HASHTABLE_SIZE 0x10000
 110 #define BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE 0x10000
 111 #define BTRFSIC_DEV2STATE_HASHTABLE_SIZE 0x100
 112 #define BTRFSIC_BLOCK_MAGIC_NUMBER 0x14491051
 113 #define BTRFSIC_BLOCK_LINK_MAGIC_NUMBER 0x11070807
 114 #define BTRFSIC_DEV2STATE_MAGIC_NUMBER 0x20111530
 115 #define BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER 20111300
 116 #define BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL (200 - 6)    /* in characters,
 117                                                          * excluding " [...]" */
 118 #define BTRFSIC_GENERATION_UNKNOWN ((u64)-1)
 119
 120 /*
 121  * The definition of the bitmask fields for the print_mask.
 122  * They are specified with the mount option check_integrity_print_mask.
 123  */
 124 #define BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE                     0x00000001
 125 #define BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION         0x00000002
 126 #define BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE                  0x00000004
 127 #define BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE                 0x00000008
 128 #define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH                        0x00000010
 129 #define BTRFSIC_PRINT_MASK_END_IO_BIO_BH                        0x00000020
 130 #define BTRFSIC_PRINT_MASK_VERBOSE                              0x00000040
 131 #define BTRFSIC_PRINT_MASK_VERY_VERBOSE                         0x00000080
 132 #define BTRFSIC_PRINT_MASK_INITIAL_TREE                         0x00000100
 133 #define BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES                    0x00000200
 134 #define BTRFSIC_PRINT_MASK_INITIAL_DATABASE                     0x00000400
 135 #define BTRFSIC_PRINT_MASK_NUM_COPIES                           0x00000800
 136 #define BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS                0x00001000
 137 #define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE                0x00002000
 138
 139 struct btrfsic_dev_state;
 140 struct btrfsic_state;
 141
 142 struct btrfsic_block {
 143         u32 magic_num;          /* only used for debug purposes */
 144         unsigned int is_metadata:1;     /* if it is meta-data, not data-data */
 145         unsigned int is_superblock:1;   /* if it is one of the superblocks */
 146         unsigned int is_iodone:1;       /* if is done by lower subsystem */
 147         unsigned int iodone_w_error:1;  /* error was indicated to endio */
 148         unsigned int never_written:1;   /* block was added because it was
 149                                          * referenced, not because it was
 150                                          * written */
 151         unsigned int mirror_num;        /* large enough to hold
 152                                          * BTRFS_SUPER_MIRROR_MAX */
 153         struct btrfsic_dev_state *dev_state;
 154         u64 dev_bytenr;         /* key, physical byte num on disk */
 155         u64 logical_bytenr;     /* logical byte num on disk */
 156         u64 generation;
 157         struct btrfs_disk_key disk_key; /* extra info to print in case of
 158                                          * issues, will not always be correct */
 159         struct list_head collision_resolving_node;      /* list node */
 160         struct list_head all_blocks_node;       /* list node */
 161
 162         /* the following two lists contain block_link items */
 163         struct list_head ref_to_list;   /* list */
 164         struct list_head ref_from_list; /* list */
 165         struct btrfsic_block *next_in_same_bio;
 166         void *orig_bio_bh_private;
 167         union {
 168                 bio_end_io_t *bio;
 169                 bh_end_io_t *bh;
 170         } orig_bio_bh_end_io;
 171         int submit_bio_bh_rw;
 172         u64 flush_gen; /* only valid if !never_written */
 173 };
 174
 175 /*
 176  * Elements of this type are allocated dynamically and required because
 177  * each block object can refer to and can be ref from multiple blocks.
 178  * The key to lookup them in the hashtable is the dev_bytenr of
 179  * the block ref to plus the one from the block refered from.
 180  * The fact that they are searchable via a hashtable and that a
 181  * ref_cnt is maintained is not required for the btrfs integrity
 182  * check algorithm itself, it is only used to make the output more
 183  * beautiful in case that an error is detected (an error is defined
 184  * as a write operation to a block while that block is still referenced).
 185  */
 186 struct btrfsic_block_link {
 187         u32 magic_num;          /* only used for debug purposes */
 188         u32 ref_cnt;
 189         struct list_head node_ref_to;   /* list node */
 190         struct list_head node_ref_from; /* list node */
 191         struct list_head collision_resolving_node;      /* list node */
 192         struct btrfsic_block *block_ref_to;
 193         struct btrfsic_block *block_ref_from;
 194         u64 parent_generation;
 195 };
 196
 197 struct btrfsic_dev_state {
 198         u32 magic_num;          /* only used for debug purposes */
 199         struct block_device *bdev;
 200         struct btrfsic_state *state;
 201         struct list_head collision_resolving_node;      /* list node */
 202         struct btrfsic_block dummy_block_for_bio_bh_flush;
 203         u64 last_flush_gen;
 204         char name[BDEVNAME_SIZE];
 205 };
 206
 207 struct btrfsic_block_hashtable {
 208         struct list_head table[BTRFSIC_BLOCK_HASHTABLE_SIZE];
 209 };
 210
 211 struct btrfsic_block_link_hashtable {
 212         struct list_head table[BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE];
 213 };
 214
 215 struct btrfsic_dev_state_hashtable {
 216         struct list_head table[BTRFSIC_DEV2STATE_HASHTABLE_SIZE];
 217 };
 218
 219 struct btrfsic_block_data_ctx {
 220         u64 start;              /* virtual bytenr */
 221         u64 dev_bytenr;         /* physical bytenr on device */
 222         u32 len;
 223         struct btrfsic_dev_state *dev;
 224         char **datav;
 225         struct page **pagev;
 226         void *mem_to_free;
 227 };
 228
 229 /* This structure is used to implement recursion without occupying
 230  * any stack space, refer to btrfsic_process_metablock() */
 231 struct btrfsic_stack_frame {
 232         u32 magic;
 233         u32 nr;
 234         int error;
 235         int i;
 236         int limit_nesting;
 237         int num_copies;
 238         int mirror_num;
 239         struct btrfsic_block *block;
 240         struct btrfsic_block_data_ctx *block_ctx;
 241         struct btrfsic_block *next_block;
 242         struct btrfsic_block_data_ctx next_block_ctx;
 243         struct btrfs_header *hdr;
 244         struct btrfsic_stack_frame *prev;
 245 };
 246
 247 /* Some state per mounted filesystem */
 248 struct btrfsic_state {
 249         u32 print_mask;
 250         int include_extent_data;
 251         int csum_size;
 252         struct list_head all_blocks_list;
 253         struct btrfsic_block_hashtable block_hashtable;
 254         struct btrfsic_block_link_hashtable block_link_hashtable;
 255         struct btrfs_root *root;
 256         u64 max_superblock_generation;
 257         struct btrfsic_block *latest_superblock;
 258         u32 metablock_size;
 259         u32 datablock_size;
 260 };
 261
 262 static void btrfsic_block_init(struct btrfsic_block *b);
 263 static struct btrfsic_block *btrfsic_block_alloc(void);
 264 static void btrfsic_block_free(struct btrfsic_block *b);
 265 static void btrfsic_block_link_init(struct btrfsic_block_link *n);
 266 static struct btrfsic_block_link *btrfsic_block_link_alloc(void);
 267 static void btrfsic_block_link_free(struct btrfsic_block_link *n);
 268 static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds);
 269 static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void);
 270 static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds);
 271 static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h);
 272 static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
 273                                         struct btrfsic_block_hashtable *h);
 274 static void btrfsic_block_hashtable_remove(struct btrfsic_block *b);
 275 static struct btrfsic_block *btrfsic_block_hashtable_lookup(
 276                 struct block_device *bdev,
 277                 u64 dev_bytenr,
 278                 struct btrfsic_block_hashtable *h);
 279 static void btrfsic_block_link_hashtable_init(
 280                 struct btrfsic_block_link_hashtable *h);
 281 static void btrfsic_block_link_hashtable_add(
 282                 struct btrfsic_block_link *l,
 283                 struct btrfsic_block_link_hashtable *h);
 284 static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l);
 285 static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
 286                 struct block_device *bdev_ref_to,
 287                 u64 dev_bytenr_ref_to,
 288                 struct block_device *bdev_ref_from,
 289                 u64 dev_bytenr_ref_from,
 290                 struct btrfsic_block_link_hashtable *h);
 291 static void btrfsic_dev_state_hashtable_init(
 292                 struct btrfsic_dev_state_hashtable *h);
 293 static void btrfsic_dev_state_hashtable_add(
 294                 struct btrfsic_dev_state *ds,
 295                 struct btrfsic_dev_state_hashtable *h);
 296 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds);
 297 static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
 298                 struct block_device *bdev,
 299                 struct btrfsic_dev_state_hashtable *h);
 300 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void);
 301 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf);
 302 static int btrfsic_process_superblock(struct btrfsic_state *state,
 303                                       struct btrfs_fs_devices *fs_devices);
 304 static int btrfsic_process_metablock(struct btrfsic_state *state,
 305                                      struct btrfsic_block *block,
 306                                      struct btrfsic_block_data_ctx *block_ctx,
 307                                      int limit_nesting, int force_iodone_flag);
 308 static void btrfsic_read_from_block_data(
 309         struct btrfsic_block_data_ctx *block_ctx,
 310         void *dst, u32 offset, size_t len);
 311 static int btrfsic_create_link_to_next_block(
 312                 struct btrfsic_state *state,
 313                 struct btrfsic_block *block,
 314                 struct btrfsic_block_data_ctx
 315                 *block_ctx, u64 next_bytenr,
 316                 int limit_nesting,
 317                 struct btrfsic_block_data_ctx *next_block_ctx,
 318                 struct btrfsic_block **next_blockp,
 319                 int force_iodone_flag,
 320                 int *num_copiesp, int *mirror_nump,
 321                 struct btrfs_disk_key *disk_key,
 322                 u64 parent_generation);
 323 static int btrfsic_handle_extent_data(struct btrfsic_state *state,
 324                                       struct btrfsic_block *block,
 325                                       struct btrfsic_block_data_ctx *block_ctx,
 326                                       u32 item_offset, int force_iodone_flag);
 327 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
 328                              struct btrfsic_block_data_ctx *block_ctx_out,
 329                              int mirror_num);
 330 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx);
 331 static int btrfsic_read_block(struct btrfsic_state *state,
 332                               struct btrfsic_block_data_ctx *block_ctx);
 333 static void btrfsic_dump_database(struct btrfsic_state *state);
 334 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
 335                                      char **datav, unsigned int num_pages);
 336 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
 337                                           u64 dev_bytenr, char **mapped_datav,
 338                                           unsigned int num_pages,
 339                                           struct bio *bio, int *bio_is_patched,
 340                                           struct buffer_head *bh,
 341                                           int submit_bio_bh_rw);
 342 static int btrfsic_process_written_superblock(
 343                 struct btrfsic_state *state,
 344                 struct btrfsic_block *const block,
 345                 struct btrfs_super_block *const super_hdr);
 346 static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status);
 347 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate);
 348 static int btrfsic_is_block_ref_by_superblock(const struct btrfsic_state *state,
 349                                               const struct btrfsic_block *block,
 350                                               int recursion_level);
 351 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
 352                                         struct btrfsic_block *const block,
 353                                         int recursion_level);
 354 static void btrfsic_print_add_link(const struct btrfsic_state *state,
 355                                    const struct btrfsic_block_link *l);
 356 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
 357                                    const struct btrfsic_block_link *l);
 358 static char btrfsic_get_block_type(const struct btrfsic_state *state,
 359                                    const struct btrfsic_block *block);
 360 static void btrfsic_dump_tree(const struct btrfsic_state *state);
 361 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
 362                                   const struct btrfsic_block *block,
 363                                   int indent_level);
 364 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
 365                 struct btrfsic_state *state,
 366                 struct btrfsic_block_data_ctx *next_block_ctx,
 367                 struct btrfsic_block *next_block,
 368                 struct btrfsic_block *from_block,
 369                 u64 parent_generation);
 370 static struct btrfsic_block *btrfsic_block_lookup_or_add(
 371                 struct btrfsic_state *state,
 372                 struct btrfsic_block_data_ctx *block_ctx,
 373                 const char *additional_string,
 374                 int is_metadata,
 375                 int is_iodone,
 376                 int never_written,
 377                 int mirror_num,
 378                 int *was_created);
 379 static int btrfsic_process_superblock_dev_mirror(
 380                 struct btrfsic_state *state,
 381                 struct btrfsic_dev_state *dev_state,
 382                 struct btrfs_device *device,
 383                 int superblock_mirror_num,
 384                 struct btrfsic_dev_state **selected_dev_state,
 385                 struct btrfs_super_block *selected_super);
 386 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
 387                 struct block_device *bdev);
 388 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
 389                                            u64 bytenr,
 390                                            struct btrfsic_dev_state *dev_state,
 391                                            u64 dev_bytenr);
 392
 393 static struct mutex btrfsic_mutex;
 394 static int btrfsic_is_initialized;
 395 static struct btrfsic_dev_state_hashtable btrfsic_dev_state_hashtable;
 396
 397
 398 static void btrfsic_block_init(struct btrfsic_block *b)
 399 {
 400         b->magic_num = BTRFSIC_BLOCK_MAGIC_NUMBER;
 401         b->dev_state = NULL;
 402         b->dev_bytenr = 0;
 403         b->logical_bytenr = 0;
 404         b->generation = BTRFSIC_GENERATION_UNKNOWN;
 405         b->disk_key.objectid = 0;
 406         b->disk_key.type = 0;
 407         b->disk_key.offset = 0;
 408         b->is_metadata = 0;
 409         b->is_superblock = 0;
 410         b->is_iodone = 0;
 411         b->iodone_w_error = 0;
 412         b->never_written = 0;
 413         b->mirror_num = 0;
 414         b->next_in_same_bio = NULL;
 415         b->orig_bio_bh_private = NULL;
 416         b->orig_bio_bh_end_io.bio = NULL;
 417         INIT_LIST_HEAD(&b->collision_resolving_node);
 418         INIT_LIST_HEAD(&b->all_blocks_node);
 419         INIT_LIST_HEAD(&b->ref_to_list);
 420         INIT_LIST_HEAD(&b->ref_from_list);
 421         b->submit_bio_bh_rw = 0;
 422         b->flush_gen = 0;
 423 }
 424
 425 static struct btrfsic_block *btrfsic_block_alloc(void)
 426 {
 427         struct btrfsic_block *b;
 428
 429         b = kzalloc(sizeof(*b), GFP_NOFS);
 430         if (NULL != b)
 431                 btrfsic_block_init(b);
 432
 433         return b;
 434 }
 435
 436 static void btrfsic_block_free(struct btrfsic_block *b)
 437 {
 438         BUG_ON(!(NULL == b || BTRFSIC_BLOCK_MAGIC_NUMBER == b->magic_num));
 439         kfree(b);
 440 }
 441
 442 static void btrfsic_block_link_init(struct btrfsic_block_link *l)
 443 {
 444         l->magic_num = BTRFSIC_BLOCK_LINK_MAGIC_NUMBER;
 445         l->ref_cnt = 1;
 446         INIT_LIST_HEAD(&l->node_ref_to);
 447         INIT_LIST_HEAD(&l->node_ref_from);
 448         INIT_LIST_HEAD(&l->collision_resolving_node);
 449         l->block_ref_to = NULL;
 450         l->block_ref_from = NULL;
 451 }
 452
 453 static struct btrfsic_block_link *btrfsic_block_link_alloc(void)
 454 {
 455         struct btrfsic_block_link *l;
 456
 457         l = kzalloc(sizeof(*l), GFP_NOFS);
 458         if (NULL != l)
 459                 btrfsic_block_link_init(l);
 460
 461         return l;
 462 }
 463
 464 static void btrfsic_block_link_free(struct btrfsic_block_link *l)
 465 {
 466         BUG_ON(!(NULL == l || BTRFSIC_BLOCK_LINK_MAGIC_NUMBER == l->magic_num));
 467         kfree(l);
 468 }
 469
 470 static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds)
 471 {
 472         ds->magic_num = BTRFSIC_DEV2STATE_MAGIC_NUMBER;
 473         ds->bdev = NULL;
 474         ds->state = NULL;
 475         ds->name[0] = '\0';
 476         INIT_LIST_HEAD(&ds->collision_resolving_node);
 477         ds->last_flush_gen = 0;
 478         btrfsic_block_init(&ds->dummy_block_for_bio_bh_flush);
 479         ds->dummy_block_for_bio_bh_flush.is_iodone = 1;
 480         ds->dummy_block_for_bio_bh_flush.dev_state = ds;
 481 }
 482
 483 static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void)
 484 {
 485         struct btrfsic_dev_state *ds;
 486
 487         ds = kzalloc(sizeof(*ds), GFP_NOFS);
 488         if (NULL != ds)
 489                 btrfsic_dev_state_init(ds);
 490
 491         return ds;
 492 }
 493
 494 static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds)
 495 {
 496         BUG_ON(!(NULL == ds ||
 497                  BTRFSIC_DEV2STATE_MAGIC_NUMBER == ds->magic_num));
 498         kfree(ds);
 499 }
 500
 501 static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h)
 502 {
 503         int i;
 504
 505         for (i = 0; i < BTRFSIC_BLOCK_HASHTABLE_SIZE; i++)
 506                 INIT_LIST_HEAD(h->table + i);
 507 }
 508
 509 static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
 510                                         struct btrfsic_block_hashtable *h)
 511 {
 512         const unsigned int hashval =
 513             (((unsigned int)(b->dev_bytenr >> 16)) ^
 514              ((unsigned int)((uintptr_t)b->dev_state->bdev))) &
 515              (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
 516
 517         list_add(&b->collision_resolving_node, h->table + hashval);
 518 }
 519
 520 static void btrfsic_block_hashtable_remove(struct btrfsic_block *b)
 521 {
 522         list_del(&b->collision_resolving_node);
 523 }
 524
 525 static struct btrfsic_block *btrfsic_block_hashtable_lookup(
 526                 struct block_device *bdev,
 527                 u64 dev_bytenr,
 528                 struct btrfsic_block_hashtable *h)
 529 {
 530         const unsigned int hashval =
 531             (((unsigned int)(dev_bytenr >> 16)) ^
 532              ((unsigned int)((uintptr_t)bdev))) &
 533              (BTRFSIC_BLOCK_HASHTABLE_SIZE - 1);
 534         struct list_head *elem;
 535
 536         list_for_each(elem, h->table + hashval) {
 537                 struct btrfsic_block *const b =
 538                     list_entry(elem, struct btrfsic_block,
 539                                collision_resolving_node);
 540
 541                 if (b->dev_state->bdev == bdev && b->dev_bytenr == dev_bytenr)
 542                         return b;
 543         }
 544
 545         return NULL;
 546 }
 547
 548 static void btrfsic_block_link_hashtable_init(
 549                 struct btrfsic_block_link_hashtable *h)
 550 {
 551         int i;
 552
 553         for (i = 0; i < BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE; i++)
 554                 INIT_LIST_HEAD(h->table + i);
 555 }
 556
 557 static void btrfsic_block_link_hashtable_add(
 558                 struct btrfsic_block_link *l,
 559                 struct btrfsic_block_link_hashtable *h)
 560 {
 561         const unsigned int hashval =
 562             (((unsigned int)(l->block_ref_to->dev_bytenr >> 16)) ^
 563              ((unsigned int)(l->block_ref_from->dev_bytenr >> 16)) ^
 564              ((unsigned int)((uintptr_t)l->block_ref_to->dev_state->bdev)) ^
 565              ((unsigned int)((uintptr_t)l->block_ref_from->dev_state->bdev)))
 566              & (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
 567
 568         BUG_ON(NULL == l->block_ref_to);
 569         BUG_ON(NULL == l->block_ref_from);
 570         list_add(&l->collision_resolving_node, h->table + hashval);
 571 }
 572
 573 static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l)
 574 {
 575         list_del(&l->collision_resolving_node);
 576 }
 577
 578 static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
 579                 struct block_device *bdev_ref_to,
 580                 u64 dev_bytenr_ref_to,
 581                 struct block_device *bdev_ref_from,
 582                 u64 dev_bytenr_ref_from,
 583                 struct btrfsic_block_link_hashtable *h)
 584 {
 585         const unsigned int hashval =
 586             (((unsigned int)(dev_bytenr_ref_to >> 16)) ^
 587              ((unsigned int)(dev_bytenr_ref_from >> 16)) ^
 588              ((unsigned int)((uintptr_t)bdev_ref_to)) ^
 589              ((unsigned int)((uintptr_t)bdev_ref_from))) &
 590              (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
 591         struct list_head *elem;
 592
 593         list_for_each(elem, h->table + hashval) {
 594                 struct btrfsic_block_link *const l =
 595                     list_entry(elem, struct btrfsic_block_link,
 596                                collision_resolving_node);
 597
 598                 BUG_ON(NULL == l->block_ref_to);
 599                 BUG_ON(NULL == l->block_ref_from);
 600                 if (l->block_ref_to->dev_state->bdev == bdev_ref_to &&
 601                     l->block_ref_to->dev_bytenr == dev_bytenr_ref_to &&
 602                     l->block_ref_from->dev_state->bdev == bdev_ref_from &&
 603                     l->block_ref_from->dev_bytenr == dev_bytenr_ref_from)
 604                         return l;
 605         }
 606
 607         return NULL;
 608 }
 609
 610 static void btrfsic_dev_state_hashtable_init(
 611                 struct btrfsic_dev_state_hashtable *h)
 612 {
 613         int i;
 614
 615         for (i = 0; i < BTRFSIC_DEV2STATE_HASHTABLE_SIZE; i++)
 616                 INIT_LIST_HEAD(h->table + i);
 617 }
 618
 619 static void btrfsic_dev_state_hashtable_add(
 620                 struct btrfsic_dev_state *ds,
 621                 struct btrfsic_dev_state_hashtable *h)
 622 {
 623         const unsigned int hashval =
 624             (((unsigned int)((uintptr_t)ds->bdev)) &
 625              (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
 626
 627         list_add(&ds->collision_resolving_node, h->table + hashval);
 628 }
 629
 630 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds)
 631 {
 632         list_del(&ds->collision_resolving_node);
 633 }
 634
 635 static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(
 636                 struct block_device *bdev,
 637                 struct btrfsic_dev_state_hashtable *h)
 638 {
 639         const unsigned int hashval =
 640             (((unsigned int)((uintptr_t)bdev)) &
 641              (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
 642         struct list_head *elem;
 643
 644         list_for_each(elem, h->table + hashval) {
 645                 struct btrfsic_dev_state *const ds =
 646                     list_entry(elem, struct btrfsic_dev_state,
 647                                collision_resolving_node);
 648
 649                 if (ds->bdev == bdev)
 650                         return ds;
 651         }
 652
 653         return NULL;
 654 }
 655
 656 static int btrfsic_process_superblock(struct btrfsic_state *state,
 657                                       struct btrfs_fs_devices *fs_devices)
 658 {
 659         int ret = 0;
 660         struct btrfs_super_block *selected_super;
 661         struct list_head *dev_head = &fs_devices->devices;
 662         struct btrfs_device *device;
 663         struct btrfsic_dev_state *selected_dev_state = NULL;
 664         int pass;
 665
 666         BUG_ON(NULL == state);
 667         selected_super = kzalloc(sizeof(*selected_super), GFP_NOFS);
 668         if (NULL == selected_super) {
 669                 printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
 670                 return -1;
 671         }
 672
 673         list_for_each_entry(device, dev_head, dev_list) {
 674                 int i;
 675                 struct btrfsic_dev_state *dev_state;
 676
 677                 if (!device->bdev || !device->name)
 678                         continue;
 679
 680                 dev_state = btrfsic_dev_state_lookup(device->bdev);
 681                 BUG_ON(NULL == dev_state);
 682                 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 683                         ret = btrfsic_process_superblock_dev_mirror(
 684                                         state, dev_state, device, i,
 685                                         &selected_dev_state, selected_super);
 686                         if (0 != ret && 0 == i) {
 687                                 kfree(selected_super);
 688                                 return ret;
 689                         }
 690                 }
 691         }
 692
 693         if (NULL == state->latest_superblock) {
 694                 printk(KERN_INFO "btrfsic: no superblock found!\n");
 695                 kfree(selected_super);
 696                 return -1;
 697         }
 698
 699         state->csum_size = btrfs_super_csum_size(selected_super);
 700
 701         for (pass = 0; pass < 3; pass++) {
 702                 int num_copies;
 703                 int mirror_num;
 704                 u64 next_bytenr;
 705
 706                 switch (pass) {
 707                 case 0:
 708                         next_bytenr = btrfs_super_root(selected_super);
 709                         if (state->print_mask &
 710                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 711                                 printk(KERN_INFO "root@%llu\n", next_bytenr);
 712                         break;
 713                 case 1:
 714                         next_bytenr = btrfs_super_chunk_root(selected_super);
 715                         if (state->print_mask &
 716                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 717                                 printk(KERN_INFO "chunk@%llu\n", next_bytenr);
 718                         break;
 719                 case 2:
 720                         next_bytenr = btrfs_super_log_root(selected_super);
 721                         if (0 == next_bytenr)
 722                                 continue;
 723                         if (state->print_mask &
 724                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 725                                 printk(KERN_INFO "log@%llu\n", next_bytenr);
 726                         break;
 727                 }
 728
 729                 num_copies =
 730                     btrfs_num_copies(state->root->fs_info,
 731                                      next_bytenr, state->metablock_size);
 732                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 733                         printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
 734                                next_bytenr, num_copies);
 735
 736                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 737                         struct btrfsic_block *next_block;
 738                         struct btrfsic_block_data_ctx tmp_next_block_ctx;
 739                         struct btrfsic_block_link *l;
 740
 741                         ret = btrfsic_map_block(state, next_bytenr,
 742                                                 state->metablock_size,
 743                                                 &tmp_next_block_ctx,
 744                                                 mirror_num);
 745                         if (ret) {
 746                                 printk(KERN_INFO "btrfsic:"
 747                                        " btrfsic_map_block(root @%llu,"
 748                                        " mirror %d) failed!\n",
 749                                        next_bytenr, mirror_num);
 750                                 kfree(selected_super);
 751                                 return -1;
 752                         }
 753
 754                         next_block = btrfsic_block_hashtable_lookup(
 755                                         tmp_next_block_ctx.dev->bdev,
 756                                         tmp_next_block_ctx.dev_bytenr,
 757                                         &state->block_hashtable);
 758                         BUG_ON(NULL == next_block);
 759
 760                         l = btrfsic_block_link_hashtable_lookup(
 761                                         tmp_next_block_ctx.dev->bdev,
 762                                         tmp_next_block_ctx.dev_bytenr,
 763                                         state->latest_superblock->dev_state->
 764                                         bdev,
 765                                         state->latest_superblock->dev_bytenr,
 766                                         &state->block_link_hashtable);
 767                         BUG_ON(NULL == l);
 768
 769                         ret = btrfsic_read_block(state, &tmp_next_block_ctx);
 770                         if (ret < (int)PAGE_CACHE_SIZE) {
 771                                 printk(KERN_INFO
 772                                        "btrfsic: read @logical %llu failed!\n",
 773                                        tmp_next_block_ctx.start);
 774                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
 775                                 kfree(selected_super);
 776                                 return -1;
 777                         }
 778
 779                         ret = btrfsic_process_metablock(state,
 780                                                         next_block,
 781                                                         &tmp_next_block_ctx,
 782                                                         BTRFS_MAX_LEVEL + 3, 1);
 783                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
 784                 }
 785         }
 786
 787         kfree(selected_super);
 788         return ret;
 789 }
 790
 791 static int btrfsic_process_superblock_dev_mirror(
 792                 struct btrfsic_state *state,
 793                 struct btrfsic_dev_state *dev_state,
 794                 struct btrfs_device *device,
 795                 int superblock_mirror_num,
 796                 struct btrfsic_dev_state **selected_dev_state,
 797                 struct btrfs_super_block *selected_super)
 798 {
 799         struct btrfs_super_block *super_tmp;
 800         u64 dev_bytenr;
 801         struct buffer_head *bh;
 802         struct btrfsic_block *superblock_tmp;
 803         int pass;
 804         struct block_device *const superblock_bdev = device->bdev;
 805
 806         /* super block bytenr is always the unmapped device bytenr */
 807         dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
 808         if (dev_bytenr + BTRFS_SUPER_INFO_SIZE > device->commit_total_bytes)
 809                 return -1;
 810         bh = __bread(superblock_bdev, dev_bytenr / 4096,
 811                      BTRFS_SUPER_INFO_SIZE);
 812         if (NULL == bh)
 813                 return -1;
 814         super_tmp = (struct btrfs_super_block *)
 815             (bh->b_data + (dev_bytenr & 4095));
 816
 817         if (btrfs_super_bytenr(super_tmp) != dev_bytenr ||
 818             btrfs_super_magic(super_tmp) != BTRFS_MAGIC ||
 819             memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE) ||
 820             btrfs_super_nodesize(super_tmp) != state->metablock_size ||
 821             btrfs_super_sectorsize(super_tmp) != state->datablock_size) {
 822                 brelse(bh);
 823                 return 0;
 824         }
 825
 826         superblock_tmp =
 827             btrfsic_block_hashtable_lookup(superblock_bdev,
 828                                            dev_bytenr,
 829                                            &state->block_hashtable);
 830         if (NULL == superblock_tmp) {
 831                 superblock_tmp = btrfsic_block_alloc();
 832                 if (NULL == superblock_tmp) {
 833                         printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
 834                         brelse(bh);
 835                         return -1;
 836                 }
 837                 /* for superblock, only the dev_bytenr makes sense */
 838                 superblock_tmp->dev_bytenr = dev_bytenr;
 839                 superblock_tmp->dev_state = dev_state;
 840                 superblock_tmp->logical_bytenr = dev_bytenr;
 841                 superblock_tmp->generation = btrfs_super_generation(super_tmp);
 842                 superblock_tmp->is_metadata = 1;
 843                 superblock_tmp->is_superblock = 1;
 844                 superblock_tmp->is_iodone = 1;
 845                 superblock_tmp->never_written = 0;
 846                 superblock_tmp->mirror_num = 1 + superblock_mirror_num;
 847                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
 848                         printk_in_rcu(KERN_INFO "New initial S-block (bdev %p, %s)"
 849                                      " @%llu (%s/%llu/%d)\n",
 850                                      superblock_bdev,
 851                                      rcu_str_deref(device->name), dev_bytenr,
 852                                      dev_state->name, dev_bytenr,
 853                                      superblock_mirror_num);
 854                 list_add(&superblock_tmp->all_blocks_node,
 855                          &state->all_blocks_list);
 856                 btrfsic_block_hashtable_add(superblock_tmp,
 857                                             &state->block_hashtable);
 858         }
 859
 860         /* select the one with the highest generation field */
 861         if (btrfs_super_generation(super_tmp) >
 862             state->max_superblock_generation ||
 863             0 == state->max_superblock_generation) {
 864                 memcpy(selected_super, super_tmp, sizeof(*selected_super));
 865                 *selected_dev_state = dev_state;
 866                 state->max_superblock_generation =
 867                     btrfs_super_generation(super_tmp);
 868                 state->latest_superblock = superblock_tmp;
 869         }
 870
 871         for (pass = 0; pass < 3; pass++) {
 872                 u64 next_bytenr;
 873                 int num_copies;
 874                 int mirror_num;
 875                 const char *additional_string = NULL;
 876                 struct btrfs_disk_key tmp_disk_key;
 877
 878                 tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
 879                 tmp_disk_key.offset = 0;
 880                 switch (pass) {
 881                 case 0:
 882                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 883                                                     BTRFS_ROOT_TREE_OBJECTID);
 884                         additional_string = "initial root ";
 885                         next_bytenr = btrfs_super_root(super_tmp);
 886                         break;
 887                 case 1:
 888                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 889                                                     BTRFS_CHUNK_TREE_OBJECTID);
 890                         additional_string = "initial chunk ";
 891                         next_bytenr = btrfs_super_chunk_root(super_tmp);
 892                         break;
 893                 case 2:
 894                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 895                                                     BTRFS_TREE_LOG_OBJECTID);
 896                         additional_string = "initial log ";
 897                         next_bytenr = btrfs_super_log_root(super_tmp);
 898                         if (0 == next_bytenr)
 899                                 continue;
 900                         break;
 901                 }
 902
 903                 num_copies =
 904                     btrfs_num_copies(state->root->fs_info,
 905                                      next_bytenr, state->metablock_size);
 906                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 907                         printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
 908                                next_bytenr, num_copies);
 909                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 910                         struct btrfsic_block *next_block;
 911                         struct btrfsic_block_data_ctx tmp_next_block_ctx;
 912                         struct btrfsic_block_link *l;
 913
 914                         if (btrfsic_map_block(state, next_bytenr,
 915                                               state->metablock_size,
 916                                               &tmp_next_block_ctx,
 917                                               mirror_num)) {
 918                                 printk(KERN_INFO "btrfsic: btrfsic_map_block("
 919                                        "bytenr @%llu, mirror %d) failed!\n",
 920                                        next_bytenr, mirror_num);
 921                                 brelse(bh);
 922                                 return -1;
 923                         }
 924
 925                         next_block = btrfsic_block_lookup_or_add(
 926                                         state, &tmp_next_block_ctx,
 927                                         additional_string, 1, 1, 0,
 928                                         mirror_num, NULL);
 929                         if (NULL == next_block) {
 930                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
 931                                 brelse(bh);
 932                                 return -1;
 933                         }
 934
 935                         next_block->disk_key = tmp_disk_key;
 936                         next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
 937                         l = btrfsic_block_link_lookup_or_add(
 938                                         state, &tmp_next_block_ctx,
 939                                         next_block, superblock_tmp,
 940                                         BTRFSIC_GENERATION_UNKNOWN);
 941                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
 942                         if (NULL == l) {
 943                                 brelse(bh);
 944                                 return -1;
 945                         }
 946                 }
 947         }
 948         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES)
 949                 btrfsic_dump_tree_sub(state, superblock_tmp, 0);
 950
 951         brelse(bh);
 952         return 0;
 953 }
 954
 955 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void)
 956 {
 957         struct btrfsic_stack_frame *sf;
 958
 959         sf = kzalloc(sizeof(*sf), GFP_NOFS);
 960         if (NULL == sf)
 961                 printk(KERN_INFO "btrfsic: alloc memory failed!\n");
 962         else
 963                 sf->magic = BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER;
 964         return sf;
 965 }
 966
 967 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf)
 968 {
 969         BUG_ON(!(NULL == sf ||
 970                  BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER == sf->magic));
 971         kfree(sf);
 972 }
 973
 974 static int btrfsic_process_metablock(
 975                 struct btrfsic_state *state,
 976                 struct btrfsic_block *const first_block,
 977                 struct btrfsic_block_data_ctx *const first_block_ctx,
 978                 int first_limit_nesting, int force_iodone_flag)
 979 {
 980         struct btrfsic_stack_frame initial_stack_frame = { 0 };
 981         struct btrfsic_stack_frame *sf;
 982         struct btrfsic_stack_frame *next_stack;
 983         struct btrfs_header *const first_hdr =
 984                 (struct btrfs_header *)first_block_ctx->datav[0];
 985
 986         BUG_ON(!first_hdr);
 987         sf = &initial_stack_frame;
 988         sf->error = 0;
 989         sf->i = -1;
 990         sf->limit_nesting = first_limit_nesting;
 991         sf->block = first_block;
 992         sf->block_ctx = first_block_ctx;
 993         sf->next_block = NULL;
 994         sf->hdr = first_hdr;
 995         sf->prev = NULL;
 996
 997 continue_with_new_stack_frame:
 998         sf->block->generation = le64_to_cpu(sf->hdr->generation);
 999         if (0 == sf->hdr->level) {
1000                 struct btrfs_leaf *const leafhdr =
1001                     (struct btrfs_leaf *)sf->hdr;
1002
1003                 if (-1 == sf->i) {
1004                         sf->nr = btrfs_stack_header_nritems(&leafhdr->header);
1005
1006                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1007                                 printk(KERN_INFO
1008                                        "leaf %llu items %d generation %llu"
1009                                        " owner %llu\n",
1010                                        sf->block_ctx->start, sf->nr,
1011                                        btrfs_stack_header_generation(
1012                                                &leafhdr->header),
1013                                        btrfs_stack_header_owner(
1014                                                &leafhdr->header));
1015                 }
1016
1017 continue_with_current_leaf_stack_frame:
1018                 if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1019                         sf->i++;
1020                         sf->num_copies = 0;
1021                 }
1022
1023                 if (sf->i < sf->nr) {
1024                         struct btrfs_item disk_item;
1025                         u32 disk_item_offset =
1026                                 (uintptr_t)(leafhdr->items + sf->i) -
1027                                 (uintptr_t)leafhdr;
1028                         struct btrfs_disk_key *disk_key;
1029                         u8 type;
1030                         u32 item_offset;
1031                         u32 item_size;
1032
1033                         if (disk_item_offset + sizeof(struct btrfs_item) >
1034                             sf->block_ctx->len) {
1035 leaf_item_out_of_bounce_error:
1036                                 printk(KERN_INFO
1037                                        "btrfsic: leaf item out of bounce at logical %llu, dev %s\n",
1038                                        sf->block_ctx->start,
1039                                        sf->block_ctx->dev->name);
1040                                 goto one_stack_frame_backwards;
1041                         }
1042                         btrfsic_read_from_block_data(sf->block_ctx,
1043                                                      &disk_item,
1044                                                      disk_item_offset,
1045                                                      sizeof(struct btrfs_item));
1046                         item_offset = btrfs_stack_item_offset(&disk_item);
1047                         item_size = btrfs_stack_item_size(&disk_item);
1048                         disk_key = &disk_item.key;
1049                         type = btrfs_disk_key_type(disk_key);
1050
1051                         if (BTRFS_ROOT_ITEM_KEY == type) {
1052                                 struct btrfs_root_item root_item;
1053                                 u32 root_item_offset;
1054                                 u64 next_bytenr;
1055
1056                                 root_item_offset = item_offset +
1057                                         offsetof(struct btrfs_leaf, items);
1058                                 if (root_item_offset + item_size >
1059                                     sf->block_ctx->len)
1060                                         goto leaf_item_out_of_bounce_error;
1061                                 btrfsic_read_from_block_data(
1062                                         sf->block_ctx, &root_item,
1063                                         root_item_offset,
1064                                         item_size);
1065                                 next_bytenr = btrfs_root_bytenr(&root_item);
1066
1067                                 sf->error =
1068                                     btrfsic_create_link_to_next_block(
1069                                                 state,
1070                                                 sf->block,
1071                                                 sf->block_ctx,
1072                                                 next_bytenr,
1073                                                 sf->limit_nesting,
1074                                                 &sf->next_block_ctx,
1075                                                 &sf->next_block,
1076                                                 force_iodone_flag,
1077                                                 &sf->num_copies,
1078                                                 &sf->mirror_num,
1079                                                 disk_key,
1080                                                 btrfs_root_generation(
1081                                                 &root_item));
1082                                 if (sf->error)
1083                                         goto one_stack_frame_backwards;
1084
1085                                 if (NULL != sf->next_block) {
1086                                         struct btrfs_header *const next_hdr =
1087                                             (struct btrfs_header *)
1088                                             sf->next_block_ctx.datav[0];
1089
1090                                         next_stack =
1091                                             btrfsic_stack_frame_alloc();
1092                                         if (NULL == next_stack) {
1093                                                 sf->error = -1;
1094                                                 btrfsic_release_block_ctx(
1095                                                                 &sf->
1096                                                                 next_block_ctx);
1097                                                 goto one_stack_frame_backwards;
1098                                         }
1099
1100                                         next_stack->i = -1;
1101                                         next_stack->block = sf->next_block;
1102                                         next_stack->block_ctx =
1103                                             &sf->next_block_ctx;
1104                                         next_stack->next_block = NULL;
1105                                         next_stack->hdr = next_hdr;
1106                                         next_stack->limit_nesting =
1107                                             sf->limit_nesting - 1;
1108                                         next_stack->prev = sf;
1109                                         sf = next_stack;
1110                                         goto continue_with_new_stack_frame;
1111                                 }
1112                         } else if (BTRFS_EXTENT_DATA_KEY == type &&
1113                                    state->include_extent_data) {
1114                                 sf->error = btrfsic_handle_extent_data(
1115                                                 state,
1116                                                 sf->block,
1117                                                 sf->block_ctx,
1118                                                 item_offset,
1119                                                 force_iodone_flag);
1120                                 if (sf->error)
1121                                         goto one_stack_frame_backwards;
1122                         }
1123
1124                         goto continue_with_current_leaf_stack_frame;
1125                 }
1126         } else {
1127                 struct btrfs_node *const nodehdr = (struct btrfs_node *)sf->hdr;
1128
1129                 if (-1 == sf->i) {
1130                         sf->nr = btrfs_stack_header_nritems(&nodehdr->header);
1131
1132                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1133                                 printk(KERN_INFO "node %llu level %d items %d"
1134                                        " generation %llu owner %llu\n",
1135                                        sf->block_ctx->start,
1136                                        nodehdr->header.level, sf->nr,
1137                                        btrfs_stack_header_generation(
1138                                        &nodehdr->header),
1139                                        btrfs_stack_header_owner(
1140                                        &nodehdr->header));
1141                 }
1142
1143 continue_with_current_node_stack_frame:
1144                 if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1145                         sf->i++;
1146                         sf->num_copies = 0;
1147                 }
1148
1149                 if (sf->i < sf->nr) {
1150                         struct btrfs_key_ptr key_ptr;
1151                         u32 key_ptr_offset;
1152                         u64 next_bytenr;
1153
1154                         key_ptr_offset = (uintptr_t)(nodehdr->ptrs + sf->i) -
1155                                           (uintptr_t)nodehdr;
1156                         if (key_ptr_offset + sizeof(struct btrfs_key_ptr) >
1157                             sf->block_ctx->len) {
1158                                 printk(KERN_INFO
1159                                        "btrfsic: node item out of bounce at logical %llu, dev %s\n",
1160                                        sf->block_ctx->start,
1161                                        sf->block_ctx->dev->name);
1162                                 goto one_stack_frame_backwards;
1163                         }
1164                         btrfsic_read_from_block_data(
1165                                 sf->block_ctx, &key_ptr, key_ptr_offset,
1166                                 sizeof(struct btrfs_key_ptr));
1167                         next_bytenr = btrfs_stack_key_blockptr(&key_ptr);
1168
1169                         sf->error = btrfsic_create_link_to_next_block(
1170                                         state,
1171                                         sf->block,
1172                                         sf->block_ctx,
1173                                         next_bytenr,
1174                                         sf->limit_nesting,
1175                                         &sf->next_block_ctx,
1176                                         &sf->next_block,
1177                                         force_iodone_flag,
1178                                         &sf->num_copies,
1179                                         &sf->mirror_num,
1180                                         &key_ptr.key,
1181                                         btrfs_stack_key_generation(&key_ptr));
1182                         if (sf->error)
1183                                 goto one_stack_frame_backwards;
1184
1185                         if (NULL != sf->next_block) {
1186                                 struct btrfs_header *const next_hdr =
1187                                     (struct btrfs_header *)
1188                                     sf->next_block_ctx.datav[0];
1189
1190                                 next_stack = btrfsic_stack_frame_alloc();
1191                                 if (NULL == next_stack) {
1192                                         sf->error = -1;
1193                                         goto one_stack_frame_backwards;
1194                                 }
1195
1196                                 next_stack->i = -1;
1197                                 next_stack->block = sf->next_block;
1198                                 next_stack->block_ctx = &sf->next_block_ctx;
1199                                 next_stack->next_block = NULL;
1200                                 next_stack->hdr = next_hdr;
1201                                 next_stack->limit_nesting =
1202                                     sf->limit_nesting - 1;
1203                                 next_stack->prev = sf;
1204                                 sf = next_stack;
1205                                 goto continue_with_new_stack_frame;
1206                         }
1207
1208                         goto continue_with_current_node_stack_frame;
1209                 }
1210         }
1211
1212 one_stack_frame_backwards:
1213         if (NULL != sf->prev) {
1214                 struct btrfsic_stack_frame *const prev = sf->prev;
1215
1216                 /* the one for the initial block is freed in the caller */
1217                 btrfsic_release_block_ctx(sf->block_ctx);
1218
1219                 if (sf->error) {
1220                         prev->error = sf->error;
1221                         btrfsic_stack_frame_free(sf);
1222                         sf = prev;
1223                         goto one_stack_frame_backwards;
1224                 }
1225
1226                 btrfsic_stack_frame_free(sf);
1227                 sf = prev;
1228                 goto continue_with_new_stack_frame;
1229         } else {
1230                 BUG_ON(&initial_stack_frame != sf);
1231         }
1232
1233         return sf->error;
1234 }
1235
1236 static void btrfsic_read_from_block_data(
1237         struct btrfsic_block_data_ctx *block_ctx,
1238         void *dstv, u32 offset, size_t len)
1239 {
1240         size_t cur;
1241         size_t offset_in_page;
1242         char *kaddr;
1243         char *dst = (char *)dstv;
1244         size_t start_offset = block_ctx->start & ((u64)PAGE_CACHE_SIZE - 1);
1245         unsigned long i = (start_offset + offset) >> PAGE_CACHE_SHIFT;
1246
1247         WARN_ON(offset + len > block_ctx->len);
1248         offset_in_page = (start_offset + offset) & (PAGE_CACHE_SIZE - 1);
1249
1250         while (len > 0) {
1251                 cur = min(len, ((size_t)PAGE_CACHE_SIZE - offset_in_page));
1252                 BUG_ON(i >= DIV_ROUND_UP(block_ctx->len, PAGE_CACHE_SIZE));
1253                 kaddr = block_ctx->datav[i];
1254                 memcpy(dst, kaddr + offset_in_page, cur);
1255
1256                 dst += cur;
1257                 len -= cur;
1258                 offset_in_page = 0;
1259                 i++;
1260         }
1261 }
1262
1263 static int btrfsic_create_link_to_next_block(
1264                 struct btrfsic_state *state,
1265                 struct btrfsic_block *block,
1266                 struct btrfsic_block_data_ctx *block_ctx,
1267                 u64 next_bytenr,
1268                 int limit_nesting,
1269                 struct btrfsic_block_data_ctx *next_block_ctx,
1270                 struct btrfsic_block **next_blockp,
1271                 int force_iodone_flag,
1272                 int *num_copiesp, int *mirror_nump,
1273                 struct btrfs_disk_key *disk_key,
1274                 u64 parent_generation)
1275 {
1276         struct btrfsic_block *next_block = NULL;
1277         int ret;
1278         struct btrfsic_block_link *l;
1279         int did_alloc_block_link;
1280         int block_was_created;
1281
1282         *next_blockp = NULL;
1283         if (0 == *num_copiesp) {
1284                 *num_copiesp =
1285                     btrfs_num_copies(state->root->fs_info,
1286                                      next_bytenr, state->metablock_size);
1287                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1288                         printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1289                                next_bytenr, *num_copiesp);
1290                 *mirror_nump = 1;
1291         }
1292
1293         if (*mirror_nump > *num_copiesp)
1294                 return 0;
1295
1296         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1297                 printk(KERN_INFO
1298                        "btrfsic_create_link_to_next_block(mirror_num=%d)\n",
1299                        *mirror_nump);
1300         ret = btrfsic_map_block(state, next_bytenr,
1301                                 state->metablock_size,
1302                                 next_block_ctx, *mirror_nump);
1303         if (ret) {
1304                 printk(KERN_INFO
1305                        "btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1306                        next_bytenr, *mirror_nump);
1307                 btrfsic_release_block_ctx(next_block_ctx);
1308                 *next_blockp = NULL;
1309                 return -1;
1310         }
1311
1312         next_block = btrfsic_block_lookup_or_add(state,
1313                                                  next_block_ctx, "referenced ",
1314                                                  1, force_iodone_flag,
1315                                                  !force_iodone_flag,
1316                                                  *mirror_nump,
1317                                                  &block_was_created);
1318         if (NULL == next_block) {
1319                 btrfsic_release_block_ctx(next_block_ctx);
1320                 *next_blockp = NULL;
1321                 return -1;
1322         }
1323         if (block_was_created) {
1324                 l = NULL;
1325                 next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
1326         } else {
1327                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE) {
1328                         if (next_block->logical_bytenr != next_bytenr &&
1329                             !(!next_block->is_metadata &&
1330                               0 == next_block->logical_bytenr))
1331                                 printk(KERN_INFO
1332                                        "Referenced block @%llu (%s/%llu/%d) found in hash table, %c, bytenr mismatch (!= stored %llu).\n",
1333                                        next_bytenr, next_block_ctx->dev->name,
1334                                        next_block_ctx->dev_bytenr, *mirror_nump,
1335                                        btrfsic_get_block_type(state,
1336                                                               next_block),
1337                                        next_block->logical_bytenr);
1338                         else
1339                                 printk(KERN_INFO
1340                                        "Referenced block @%llu (%s/%llu/%d) found in hash table, %c.\n",
1341                                        next_bytenr, next_block_ctx->dev->name,
1342                                        next_block_ctx->dev_bytenr, *mirror_nump,
1343                                        btrfsic_get_block_type(state,
1344                                                               next_block));
1345                 }
1346                 next_block->logical_bytenr = next_bytenr;
1347
1348                 next_block->mirror_num = *mirror_nump;
1349                 l = btrfsic_block_link_hashtable_lookup(
1350                                 next_block_ctx->dev->bdev,
1351                                 next_block_ctx->dev_bytenr,
1352                                 block_ctx->dev->bdev,
1353                                 block_ctx->dev_bytenr,
1354                                 &state->block_link_hashtable);
1355         }
1356
1357         next_block->disk_key = *disk_key;
1358         if (NULL == l) {
1359                 l = btrfsic_block_link_alloc();
1360                 if (NULL == l) {
1361                         printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
1362                         btrfsic_release_block_ctx(next_block_ctx);
1363                         *next_blockp = NULL;
1364                         return -1;
1365                 }
1366
1367                 did_alloc_block_link = 1;
1368                 l->block_ref_to = next_block;
1369                 l->block_ref_from = block;
1370                 l->ref_cnt = 1;
1371                 l->parent_generation = parent_generation;
1372
1373                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1374                         btrfsic_print_add_link(state, l);
1375
1376                 list_add(&l->node_ref_to, &block->ref_to_list);
1377                 list_add(&l->node_ref_from, &next_block->ref_from_list);
1378
1379                 btrfsic_block_link_hashtable_add(l,
1380                                                  &state->block_link_hashtable);
1381         } else {
1382                 did_alloc_block_link = 0;
1383                 if (0 == limit_nesting) {
1384                         l->ref_cnt++;
1385                         l->parent_generation = parent_generation;
1386                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1387                                 btrfsic_print_add_link(state, l);
1388                 }
1389         }
1390
1391         if (limit_nesting > 0 && did_alloc_block_link) {
1392                 ret = btrfsic_read_block(state, next_block_ctx);
1393                 if (ret < (int)next_block_ctx->len) {
1394                         printk(KERN_INFO
1395                                "btrfsic: read block @logical %llu failed!\n",
1396                                next_bytenr);
1397                         btrfsic_release_block_ctx(next_block_ctx);
1398                         *next_blockp = NULL;
1399                         return -1;
1400                 }
1401
1402                 *next_blockp = next_block;
1403         } else {
1404                 *next_blockp = NULL;
1405         }
1406         (*mirror_nump)++;
1407
1408         return 0;
1409 }
1410
1411 static int btrfsic_handle_extent_data(
1412                 struct btrfsic_state *state,
1413                 struct btrfsic_block *block,
1414                 struct btrfsic_block_data_ctx *block_ctx,
1415                 u32 item_offset, int force_iodone_flag)
1416 {
1417         int ret;
1418         struct btrfs_file_extent_item file_extent_item;
1419         u64 file_extent_item_offset;
1420         u64 next_bytenr;
1421         u64 num_bytes;
1422         u64 generation;
1423         struct btrfsic_block_link *l;
1424
1425         file_extent_item_offset = offsetof(struct btrfs_leaf, items) +
1426                                   item_offset;
1427         if (file_extent_item_offset +
1428             offsetof(struct btrfs_file_extent_item, disk_num_bytes) >
1429             block_ctx->len) {
1430                 printk(KERN_INFO
1431                        "btrfsic: file item out of bounce at logical %llu, dev %s\n",
1432                        block_ctx->start, block_ctx->dev->name);
1433                 return -1;
1434         }
1435
1436         btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1437                 file_extent_item_offset,
1438                 offsetof(struct btrfs_file_extent_item, disk_num_bytes));
1439         if (BTRFS_FILE_EXTENT_REG != file_extent_item.type ||
1440             btrfs_stack_file_extent_disk_bytenr(&file_extent_item) == 0) {
1441                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1442                         printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu\n",
1443                                file_extent_item.type,
1444                                btrfs_stack_file_extent_disk_bytenr(
1445                                &file_extent_item));
1446                 return 0;
1447         }
1448
1449         if (file_extent_item_offset + sizeof(struct btrfs_file_extent_item) >
1450             block_ctx->len) {
1451                 printk(KERN_INFO
1452                        "btrfsic: file item out of bounce at logical %llu, dev %s\n",
1453                        block_ctx->start, block_ctx->dev->name);
1454                 return -1;
1455         }
1456         btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1457                                      file_extent_item_offset,
1458                                      sizeof(struct btrfs_file_extent_item));
1459         next_bytenr = btrfs_stack_file_extent_disk_bytenr(&file_extent_item);
1460         if (btrfs_stack_file_extent_compression(&file_extent_item) ==
1461             BTRFS_COMPRESS_NONE) {
1462                 next_bytenr += btrfs_stack_file_extent_offset(&file_extent_item);
1463                 num_bytes = btrfs_stack_file_extent_num_bytes(&file_extent_item);
1464         } else {
1465                 num_bytes = btrfs_stack_file_extent_disk_num_bytes(&file_extent_item);
1466         }
1467         generation = btrfs_stack_file_extent_generation(&file_extent_item);
1468
1469         if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1470                 printk(KERN_INFO "extent_data: type %u, disk_bytenr = %llu,"
1471                        " offset = %llu, num_bytes = %llu\n",
1472                        file_extent_item.type,
1473                        btrfs_stack_file_extent_disk_bytenr(&file_extent_item),
1474                        btrfs_stack_file_extent_offset(&file_extent_item),
1475                        num_bytes);
1476         while (num_bytes > 0) {
1477                 u32 chunk_len;
1478                 int num_copies;
1479                 int mirror_num;
1480
1481                 if (num_bytes > state->datablock_size)
1482                         chunk_len = state->datablock_size;
1483                 else
1484                         chunk_len = num_bytes;
1485
1486                 num_copies =
1487                     btrfs_num_copies(state->root->fs_info,
1488                                      next_bytenr, state->datablock_size);
1489                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1490                         printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
1491                                next_bytenr, num_copies);
1492                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
1493                         struct btrfsic_block_data_ctx next_block_ctx;
1494                         struct btrfsic_block *next_block;
1495                         int block_was_created;
1496
1497                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1498                                 printk(KERN_INFO "btrfsic_handle_extent_data("
1499                                        "mirror_num=%d)\n", mirror_num);
1500                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1501                                 printk(KERN_INFO
1502                                        "\tdisk_bytenr = %llu, num_bytes %u\n",
1503                                        next_bytenr, chunk_len);
1504                         ret = btrfsic_map_block(state, next_bytenr,
1505                                                 chunk_len, &next_block_ctx,
1506                                                 mirror_num);
1507                         if (ret) {
1508                                 printk(KERN_INFO
1509                                        "btrfsic: btrfsic_map_block(@%llu,"
1510                                        " mirror=%d) failed!\n",
1511                                        next_bytenr, mirror_num);
1512                                 return -1;
1513                         }
1514
1515                         next_block = btrfsic_block_lookup_or_add(
1516                                         state,
1517                                         &next_block_ctx,
1518                                         "referenced ",
1519                                         0,
1520                                         force_iodone_flag,
1521                                         !force_iodone_flag,
1522                                         mirror_num,
1523                                         &block_was_created);
1524                         if (NULL == next_block) {
1525                                 printk(KERN_INFO
1526                                        "btrfsic: error, kmalloc failed!\n");
1527                                 btrfsic_release_block_ctx(&next_block_ctx);
1528                                 return -1;
1529                         }
1530                         if (!block_was_created) {
1531                                 if ((state->print_mask &
1532                                      BTRFSIC_PRINT_MASK_VERBOSE) &&
1533                                     next_block->logical_bytenr != next_bytenr &&
1534                                     !(!next_block->is_metadata &&
1535                                       0 == next_block->logical_bytenr)) {
1536                                         printk(KERN_INFO
1537                                                "Referenced block"
1538                                                " @%llu (%s/%llu/%d)"
1539                                                " found in hash table, D,"
1540                                                " bytenr mismatch"
1541                                                " (!= stored %llu).\n",
1542                                                next_bytenr,
1543                                                next_block_ctx.dev->name,
1544                                                next_block_ctx.dev_bytenr,
1545                                                mirror_num,
1546                                                next_block->logical_bytenr);
1547                                 }
1548                                 next_block->logical_bytenr = next_bytenr;
1549                                 next_block->mirror_num = mirror_num;
1550                         }
1551
1552                         l = btrfsic_block_link_lookup_or_add(state,
1553                                                              &next_block_ctx,
1554                                                              next_block, block,
1555                                                              generation);
1556                         btrfsic_release_block_ctx(&next_block_ctx);
1557                         if (NULL == l)
1558                                 return -1;
1559                 }
1560
1561                 next_bytenr += chunk_len;
1562                 num_bytes -= chunk_len;
1563         }
1564
1565         return 0;
1566 }
1567
1568 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
1569                              struct btrfsic_block_data_ctx *block_ctx_out,
1570                              int mirror_num)
1571 {
1572         int ret;
1573         u64 length;
1574         struct btrfs_bio *multi = NULL;
1575         struct btrfs_device *device;
1576
1577         length = len;
1578         ret = btrfs_map_block(state->root->fs_info, READ,
1579                               bytenr, &length, &multi, mirror_num);
1580
1581         if (ret) {
1582                 block_ctx_out->start = 0;
1583                 block_ctx_out->dev_bytenr = 0;
1584                 block_ctx_out->len = 0;
1585                 block_ctx_out->dev = NULL;
1586                 block_ctx_out->datav = NULL;
1587                 block_ctx_out->pagev = NULL;
1588                 block_ctx_out->mem_to_free = NULL;
1589
1590                 return ret;
1591         }
1592
1593         device = multi->stripes[0].dev;
1594         block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev);
1595         block_ctx_out->dev_bytenr = multi->stripes[0].physical;
1596         block_ctx_out->start = bytenr;
1597         block_ctx_out->len = len;
1598         block_ctx_out->datav = NULL;
1599         block_ctx_out->pagev = NULL;
1600         block_ctx_out->mem_to_free = NULL;
1601
1602         kfree(multi);
1603         if (NULL == block_ctx_out->dev) {
1604                 ret = -ENXIO;
1605                 printk(KERN_INFO "btrfsic: error, cannot lookup dev (#1)!\n");
1606         }
1607
1608         return ret;
1609 }
1610
1611 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
1612 {
1613         if (block_ctx->mem_to_free) {
1614                 unsigned int num_pages;
1615
1616                 BUG_ON(!block_ctx->datav);
1617                 BUG_ON(!block_ctx->pagev);
1618                 num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
1619                             PAGE_CACHE_SHIFT;
1620                 while (num_pages > 0) {
1621                         num_pages--;
1622                         if (block_ctx->datav[num_pages]) {
1623                                 kunmap(block_ctx->pagev[num_pages]);
1624                                 block_ctx->datav[num_pages] = NULL;
1625                         }
1626                         if (block_ctx->pagev[num_pages]) {
1627                                 __free_page(block_ctx->pagev[num_pages]);
1628                                 block_ctx->pagev[num_pages] = NULL;
1629                         }
1630                 }
1631
1632                 kfree(block_ctx->mem_to_free);
1633                 block_ctx->mem_to_free = NULL;
1634                 block_ctx->pagev = NULL;
1635                 block_ctx->datav = NULL;
1636         }
1637 }
1638
1639 static int btrfsic_read_block(struct btrfsic_state *state,
1640                               struct btrfsic_block_data_ctx *block_ctx)
1641 {
1642         unsigned int num_pages;
1643         unsigned int i;
1644         u64 dev_bytenr;
1645         int ret;
1646
1647         BUG_ON(block_ctx->datav);
1648         BUG_ON(block_ctx->pagev);
1649         BUG_ON(block_ctx->mem_to_free);
1650         if (block_ctx->dev_bytenr & ((u64)PAGE_CACHE_SIZE - 1)) {
1651                 printk(KERN_INFO
1652                        "btrfsic: read_block() with unaligned bytenr %llu\n",
1653                        block_ctx->dev_bytenr);
1654                 return -1;
1655         }
1656
1657         num_pages = (block_ctx->len + (u64)PAGE_CACHE_SIZE - 1) >>
1658                     PAGE_CACHE_SHIFT;
1659         block_ctx->mem_to_free = kzalloc((sizeof(*block_ctx->datav) +
1660                                           sizeof(*block_ctx->pagev)) *
1661                                          num_pages, GFP_NOFS);
1662         if (!block_ctx->mem_to_free)
1663                 return -1;
1664         block_ctx->datav = block_ctx->mem_to_free;
1665         block_ctx->pagev = (struct page **)(block_ctx->datav + num_pages);
1666         for (i = 0; i < num_pages; i++) {
1667                 block_ctx->pagev[i] = alloc_page(GFP_NOFS);
1668                 if (!block_ctx->pagev[i])
1669                         return -1;
1670         }
1671
1672         dev_bytenr = block_ctx->dev_bytenr;
1673         for (i = 0; i < num_pages;) {
1674                 struct bio *bio;
1675                 unsigned int j;
1676
1677                 bio = btrfs_io_bio_alloc(GFP_NOFS, num_pages - i);
1678                 if (!bio) {
1679                         printk(KERN_INFO
1680                                "btrfsic: bio_alloc() for %u pages failed!\n",
1681                                num_pages - i);
1682                         return -1;
1683                 }
1684                 bio->bi_bdev = block_ctx->dev->bdev;
1685                 bio->bi_iter.bi_sector = dev_bytenr >> 9;
1686
1687                 for (j = i; j < num_pages; j++) {
1688                         ret = bio_add_page(bio, block_ctx->pagev[j],
1689                                            PAGE_CACHE_SIZE, 0);
1690                         if (PAGE_CACHE_SIZE != ret)
1691                                 break;
1692                 }
1693                 if (j == i) {
1694                         printk(KERN_INFO
1695                                "btrfsic: error, failed to add a single page!\n");
1696                         return -1;
1697                 }
1698                 if (submit_bio_wait(READ, bio)) {
1699                         printk(KERN_INFO
1700                                "btrfsic: read error at logical %llu dev %s!\n",
1701                                block_ctx->start, block_ctx->dev->name);
1702                         bio_put(bio);
1703                         return -1;
1704                 }
1705                 bio_put(bio);
1706                 dev_bytenr += (j - i) * PAGE_CACHE_SIZE;
1707                 i = j;
1708         }
1709         for (i = 0; i < num_pages; i++) {
1710                 block_ctx->datav[i] = kmap(block_ctx->pagev[i]);
1711                 if (!block_ctx->datav[i]) {
1712                         printk(KERN_INFO "btrfsic: kmap() failed (dev %s)!\n",
1713                                block_ctx->dev->name);
1714                         return -1;
1715                 }
1716         }
1717
1718         return block_ctx->len;
1719 }
1720
1721 static void btrfsic_dump_database(struct btrfsic_state *state)
1722 {
1723         struct list_head *elem_all;
1724
1725         BUG_ON(NULL == state);
1726
1727         printk(KERN_INFO "all_blocks_list:\n");
1728         list_for_each(elem_all, &state->all_blocks_list) {
1729                 const struct btrfsic_block *const b_all =
1730                     list_entry(elem_all, struct btrfsic_block,
1731                                all_blocks_node);
1732                 struct list_head *elem_ref_to;
1733                 struct list_head *elem_ref_from;
1734
1735                 printk(KERN_INFO "%c-block @%llu (%s/%llu/%d)\n",
1736                        btrfsic_get_block_type(state, b_all),
1737                        b_all->logical_bytenr, b_all->dev_state->name,
1738                        b_all->dev_bytenr, b_all->mirror_num);
1739
1740                 list_for_each(elem_ref_to, &b_all->ref_to_list) {
1741                         const struct btrfsic_block_link *const l =
1742                             list_entry(elem_ref_to,
1743                                        struct btrfsic_block_link,
1744                                        node_ref_to);
1745
1746                         printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1747                                " refers %u* to"
1748                                " %c @%llu (%s/%llu/%d)\n",
1749                                btrfsic_get_block_type(state, b_all),
1750                                b_all->logical_bytenr, b_all->dev_state->name,
1751                                b_all->dev_bytenr, b_all->mirror_num,
1752                                l->ref_cnt,
1753                                btrfsic_get_block_type(state, l->block_ref_to),
1754                                l->block_ref_to->logical_bytenr,
1755                                l->block_ref_to->dev_state->name,
1756                                l->block_ref_to->dev_bytenr,
1757                                l->block_ref_to->mirror_num);
1758                 }
1759
1760                 list_for_each(elem_ref_from, &b_all->ref_from_list) {
1761                         const struct btrfsic_block_link *const l =
1762                             list_entry(elem_ref_from,
1763                                        struct btrfsic_block_link,
1764                                        node_ref_from);
1765
1766                         printk(KERN_INFO " %c @%llu (%s/%llu/%d)"
1767                                " is ref %u* from"
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_from),
1774                                l->block_ref_from->logical_bytenr,
1775                                l->block_ref_from->dev_state->name,
1776                                l->block_ref_from->dev_bytenr,
1777                                l->block_ref_from->mirror_num);
1778                 }
1779
1780                 printk(KERN_INFO "\n");
1781         }
1782 }
1783
1784 /*
1785  * Test whether the disk block contains a tree block (leaf or node)
1786  * (note that this test fails for the super block)
1787  */
1788 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
1789                                      char **datav, unsigned int num_pages)
1790 {
1791         struct btrfs_header *h;
1792         u8 csum[BTRFS_CSUM_SIZE];
1793         u32 crc = ~(u32)0;
1794         unsigned int i;
1795
1796         if (num_pages * PAGE_CACHE_SIZE < state->metablock_size)
1797                 return 1; /* not metadata */
1798         num_pages = state->metablock_size >> PAGE_CACHE_SHIFT;
1799         h = (struct btrfs_header *)datav[0];
1800
1801         if (memcmp(h->fsid, state->root->fs_info->fsid, BTRFS_UUID_SIZE))
1802                 return 1;
1803
1804         for (i = 0; i < num_pages; i++) {
1805                 u8 *data = i ? datav[i] : (datav[i] + BTRFS_CSUM_SIZE);
1806                 size_t sublen = i ? PAGE_CACHE_SIZE :
1807                                     (PAGE_CACHE_SIZE - BTRFS_CSUM_SIZE);
1808
1809                 crc = btrfs_crc32c(crc, data, sublen);
1810         }
1811         btrfs_csum_final(crc, csum);
1812         if (memcmp(csum, h->csum, state->csum_size))
1813                 return 1;
1814
1815         return 0; /* is metadata */
1816 }
1817
1818 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
1819                                           u64 dev_bytenr, char **mapped_datav,
1820                                           unsigned int num_pages,
1821                                           struct bio *bio, int *bio_is_patched,
1822                                           struct buffer_head *bh,
1823                                           int submit_bio_bh_rw)
1824 {
1825         int is_metadata;
1826         struct btrfsic_block *block;
1827         struct btrfsic_block_data_ctx block_ctx;
1828         int ret;
1829         struct btrfsic_state *state = dev_state->state;
1830         struct block_device *bdev = dev_state->bdev;
1831         unsigned int processed_len;
1832
1833         if (NULL != bio_is_patched)
1834                 *bio_is_patched = 0;
1835
1836 again:
1837         if (num_pages == 0)
1838                 return;
1839
1840         processed_len = 0;
1841         is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_datav,
1842                                                       num_pages));
1843
1844         block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
1845                                                &state->block_hashtable);
1846         if (NULL != block) {
1847                 u64 bytenr = 0;
1848                 struct list_head *elem_ref_to;
1849                 struct list_head *tmp_ref_to;
1850
1851                 if (block->is_superblock) {
1852                         bytenr = btrfs_super_bytenr((struct btrfs_super_block *)
1853                                                     mapped_datav[0]);
1854                         if (num_pages * PAGE_CACHE_SIZE <
1855                             BTRFS_SUPER_INFO_SIZE) {
1856                                 printk(KERN_INFO
1857                                        "btrfsic: cannot work with too short bios!\n");
1858                                 return;
1859                         }
1860                         is_metadata = 1;
1861                         BUG_ON(BTRFS_SUPER_INFO_SIZE & (PAGE_CACHE_SIZE - 1));
1862                         processed_len = BTRFS_SUPER_INFO_SIZE;
1863                         if (state->print_mask &
1864                             BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
1865                                 printk(KERN_INFO
1866                                        "[before new superblock is written]:\n");
1867                                 btrfsic_dump_tree_sub(state, block, 0);
1868                         }
1869                 }
1870                 if (is_metadata) {
1871                         if (!block->is_superblock) {
1872                                 if (num_pages * PAGE_CACHE_SIZE <
1873                                     state->metablock_size) {
1874                                         printk(KERN_INFO
1875                                                "btrfsic: cannot work with too short bios!\n");
1876                                         return;
1877                                 }
1878                                 processed_len = state->metablock_size;
1879                                 bytenr = btrfs_stack_header_bytenr(
1880                                                 (struct btrfs_header *)
1881                                                 mapped_datav[0]);
1882                                 btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
1883                                                                dev_state,
1884                                                                dev_bytenr);
1885                         }
1886                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE) {
1887                                 if (block->logical_bytenr != bytenr &&
1888                                     !(!block->is_metadata &&
1889                                       block->logical_bytenr == 0))
1890                                         printk(KERN_INFO
1891                                                "Written block @%llu (%s/%llu/%d) found in hash table, %c, bytenr mismatch (!= stored %llu).\n",
1892                                                bytenr, dev_state->name,
1893                                                dev_bytenr,
1894                                                block->mirror_num,
1895                                                btrfsic_get_block_type(state,
1896                                                                       block),
1897                                                block->logical_bytenr);
1898                                 else
1899                                         printk(KERN_INFO
1900                                                "Written block @%llu (%s/%llu/%d) found in hash table, %c.\n",
1901                                                bytenr, dev_state->name,
1902                                                dev_bytenr, block->mirror_num,
1903                                                btrfsic_get_block_type(state,
1904                                                                       block));
1905                         }
1906                         block->logical_bytenr = bytenr;
1907                 } else {
1908                         if (num_pages * PAGE_CACHE_SIZE <
1909                             state->datablock_size) {
1910                                 printk(KERN_INFO
1911                                        "btrfsic: cannot work with too short bios!\n");
1912                                 return;
1913                         }
1914                         processed_len = state->datablock_size;
1915                         bytenr = block->logical_bytenr;
1916                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1917                                 printk(KERN_INFO
1918                                        "Written block @%llu (%s/%llu/%d)"
1919                                        " found in hash table, %c.\n",
1920                                        bytenr, dev_state->name, dev_bytenr,
1921                                        block->mirror_num,
1922                                        btrfsic_get_block_type(state, block));
1923                 }
1924
1925                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1926                         printk(KERN_INFO
1927                                "ref_to_list: %cE, ref_from_list: %cE\n",
1928                                list_empty(&block->ref_to_list) ? ' ' : '!',
1929                                list_empty(&block->ref_from_list) ? ' ' : '!');
1930                 if (btrfsic_is_block_ref_by_superblock(state, block, 0)) {
1931                         printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
1932                                " @%llu (%s/%llu/%d), old(gen=%llu,"
1933                                " objectid=%llu, type=%d, offset=%llu),"
1934                                " new(gen=%llu),"
1935                                " which is referenced by most recent superblock"
1936                                " (superblockgen=%llu)!\n",
1937                                btrfsic_get_block_type(state, block), bytenr,
1938                                dev_state->name, dev_bytenr, block->mirror_num,
1939                                block->generation,
1940                                btrfs_disk_key_objectid(&block->disk_key),
1941                                block->disk_key.type,
1942                                btrfs_disk_key_offset(&block->disk_key),
1943                                btrfs_stack_header_generation(
1944                                        (struct btrfs_header *) mapped_datav[0]),
1945                                state->max_superblock_generation);
1946                         btrfsic_dump_tree(state);
1947                 }
1948
1949                 if (!block->is_iodone && !block->never_written) {
1950                         printk(KERN_INFO "btrfs: attempt to overwrite %c-block"
1951                                " @%llu (%s/%llu/%d), oldgen=%llu, newgen=%llu,"
1952                                " which is not yet iodone!\n",
1953                                btrfsic_get_block_type(state, block), bytenr,
1954                                dev_state->name, dev_bytenr, block->mirror_num,
1955                                block->generation,
1956                                btrfs_stack_header_generation(
1957                                        (struct btrfs_header *)
1958                                        mapped_datav[0]));
1959                         /* it would not be safe to go on */
1960                         btrfsic_dump_tree(state);
1961                         goto continue_loop;
1962                 }
1963
1964                 /*
1965                  * Clear all references of this block. Do not free
1966                  * the block itself even if is not referenced anymore
1967                  * because it still carries valueable information
1968                  * like whether it was ever written and IO completed.
1969                  */
1970                 list_for_each_safe(elem_ref_to, tmp_ref_to,
1971                                    &block->ref_to_list) {
1972                         struct btrfsic_block_link *const l =
1973                             list_entry(elem_ref_to,
1974                                        struct btrfsic_block_link,
1975                                        node_ref_to);
1976
1977                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1978                                 btrfsic_print_rem_link(state, l);
1979                         l->ref_cnt--;
1980                         if (0 == l->ref_cnt) {
1981                                 list_del(&l->node_ref_to);
1982                                 list_del(&l->node_ref_from);
1983                                 btrfsic_block_link_hashtable_remove(l);
1984                                 btrfsic_block_link_free(l);
1985                         }
1986                 }
1987
1988                 block_ctx.dev = dev_state;
1989                 block_ctx.dev_bytenr = dev_bytenr;
1990                 block_ctx.start = bytenr;
1991                 block_ctx.len = processed_len;
1992                 block_ctx.pagev = NULL;
1993                 block_ctx.mem_to_free = NULL;
1994                 block_ctx.datav = mapped_datav;
1995
1996                 if (is_metadata || state->include_extent_data) {
1997                         block->never_written = 0;
1998                         block->iodone_w_error = 0;
1999                         if (NULL != bio) {
2000                                 block->is_iodone = 0;
2001                                 BUG_ON(NULL == bio_is_patched);
2002                                 if (!*bio_is_patched) {
2003                                         block->orig_bio_bh_private =
2004                                             bio->bi_private;
2005                                         block->orig_bio_bh_end_io.bio =
2006                                             bio->bi_end_io;
2007                                         block->next_in_same_bio = NULL;
2008                                         bio->bi_private = block;
2009                                         bio->bi_end_io = btrfsic_bio_end_io;
2010                                         *bio_is_patched = 1;
2011                                 } else {
2012                                         struct btrfsic_block *chained_block =
2013                                             (struct btrfsic_block *)
2014                                             bio->bi_private;
2015
2016                                         BUG_ON(NULL == chained_block);
2017                                         block->orig_bio_bh_private =
2018                                             chained_block->orig_bio_bh_private;
2019                                         block->orig_bio_bh_end_io.bio =
2020                                             chained_block->orig_bio_bh_end_io.
2021                                             bio;
2022                                         block->next_in_same_bio = chained_block;
2023                                         bio->bi_private = block;
2024                                 }
2025                         } else if (NULL != bh) {
2026                                 block->is_iodone = 0;
2027                                 block->orig_bio_bh_private = bh->b_private;
2028                                 block->orig_bio_bh_end_io.bh = bh->b_end_io;
2029                                 block->next_in_same_bio = NULL;
2030                                 bh->b_private = block;
2031                                 bh->b_end_io = btrfsic_bh_end_io;
2032                         } else {
2033                                 block->is_iodone = 1;
2034                                 block->orig_bio_bh_private = NULL;
2035                                 block->orig_bio_bh_end_io.bio = NULL;
2036                                 block->next_in_same_bio = NULL;
2037                         }
2038                 }
2039
2040                 block->flush_gen = dev_state->last_flush_gen + 1;
2041                 block->submit_bio_bh_rw = submit_bio_bh_rw;
2042                 if (is_metadata) {
2043                         block->logical_bytenr = bytenr;
2044                         block->is_metadata = 1;
2045                         if (block->is_superblock) {
2046                                 BUG_ON(PAGE_CACHE_SIZE !=
2047                                        BTRFS_SUPER_INFO_SIZE);
2048                                 ret = btrfsic_process_written_superblock(
2049                                                 state,
2050                                                 block,
2051                                                 (struct btrfs_super_block *)
2052                                                 mapped_datav[0]);
2053                                 if (state->print_mask &
2054                                     BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE) {
2055                                         printk(KERN_INFO
2056                                         "[after new superblock is written]:\n");
2057                                         btrfsic_dump_tree_sub(state, block, 0);
2058                                 }
2059                         } else {
2060                                 block->mirror_num = 0;  /* unknown */
2061                                 ret = btrfsic_process_metablock(
2062                                                 state,
2063                                                 block,
2064                                                 &block_ctx,
2065                                                 0, 0);
2066                         }
2067                         if (ret)
2068                                 printk(KERN_INFO
2069                                        "btrfsic: btrfsic_process_metablock"
2070                                        "(root @%llu) failed!\n",
2071                                        dev_bytenr);
2072                 } else {
2073                         block->is_metadata = 0;
2074                         block->mirror_num = 0;  /* unknown */
2075                         block->generation = BTRFSIC_GENERATION_UNKNOWN;
2076                         if (!state->include_extent_data
2077                             && list_empty(&block->ref_from_list)) {
2078                                 /*
2079                                  * disk block is overwritten with extent
2080                                  * data (not meta data) and we are configured
2081                                  * to not include extent data: take the
2082                                  * chance and free the block's memory
2083                                  */
2084                                 btrfsic_block_hashtable_remove(block);
2085                                 list_del(&block->all_blocks_node);
2086                                 btrfsic_block_free(block);
2087                         }
2088                 }
2089                 btrfsic_release_block_ctx(&block_ctx);
2090         } else {
2091                 /* block has not been found in hash table */
2092                 u64 bytenr;
2093
2094                 if (!is_metadata) {
2095                         processed_len = state->datablock_size;
2096                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2097                                 printk(KERN_INFO "Written block (%s/%llu/?)"
2098                                        " !found in hash table, D.\n",
2099                                        dev_state->name, dev_bytenr);
2100                         if (!state->include_extent_data) {
2101                                 /* ignore that written D block */
2102                                 goto continue_loop;
2103                         }
2104
2105                         /* this is getting ugly for the
2106                          * include_extent_data case... */
2107                         bytenr = 0;     /* unknown */
2108                 } else {
2109                         processed_len = state->metablock_size;
2110                         bytenr = btrfs_stack_header_bytenr(
2111                                         (struct btrfs_header *)
2112                                         mapped_datav[0]);
2113                         btrfsic_cmp_log_and_dev_bytenr(state, bytenr, dev_state,
2114                                                        dev_bytenr);
2115                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2116                                 printk(KERN_INFO
2117                                        "Written block @%llu (%s/%llu/?)"
2118                                        " !found in hash table, M.\n",
2119                                        bytenr, dev_state->name, dev_bytenr);
2120                 }
2121
2122                 block_ctx.dev = dev_state;
2123                 block_ctx.dev_bytenr = dev_bytenr;
2124                 block_ctx.start = bytenr;
2125                 block_ctx.len = processed_len;
2126                 block_ctx.pagev = NULL;
2127                 block_ctx.mem_to_free = NULL;
2128                 block_ctx.datav = mapped_datav;
2129
2130                 block = btrfsic_block_alloc();
2131                 if (NULL == block) {
2132                         printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2133                         btrfsic_release_block_ctx(&block_ctx);
2134                         goto continue_loop;
2135                 }
2136                 block->dev_state = dev_state;
2137                 block->dev_bytenr = dev_bytenr;
2138                 block->logical_bytenr = bytenr;
2139                 block->is_metadata = is_metadata;
2140                 block->never_written = 0;
2141                 block->iodone_w_error = 0;
2142                 block->mirror_num = 0;  /* unknown */
2143                 block->flush_gen = dev_state->last_flush_gen + 1;
2144                 block->submit_bio_bh_rw = submit_bio_bh_rw;
2145                 if (NULL != bio) {
2146                         block->is_iodone = 0;
2147                         BUG_ON(NULL == bio_is_patched);
2148                         if (!*bio_is_patched) {
2149                                 block->orig_bio_bh_private = bio->bi_private;
2150                                 block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2151                                 block->next_in_same_bio = NULL;
2152                                 bio->bi_private = block;
2153                                 bio->bi_end_io = btrfsic_bio_end_io;
2154                                 *bio_is_patched = 1;
2155                         } else {
2156                                 struct btrfsic_block *chained_block =
2157                                     (struct btrfsic_block *)
2158                                     bio->bi_private;
2159
2160                                 BUG_ON(NULL == chained_block);
2161                                 block->orig_bio_bh_private =
2162                                     chained_block->orig_bio_bh_private;
2163                                 block->orig_bio_bh_end_io.bio =
2164                                     chained_block->orig_bio_bh_end_io.bio;
2165                                 block->next_in_same_bio = chained_block;
2166                                 bio->bi_private = block;
2167                         }
2168                 } else if (NULL != bh) {
2169                         block->is_iodone = 0;
2170                         block->orig_bio_bh_private = bh->b_private;
2171                         block->orig_bio_bh_end_io.bh = bh->b_end_io;
2172                         block->next_in_same_bio = NULL;
2173                         bh->b_private = block;
2174                         bh->b_end_io = btrfsic_bh_end_io;
2175                 } else {
2176                         block->is_iodone = 1;
2177                         block->orig_bio_bh_private = NULL;
2178                         block->orig_bio_bh_end_io.bio = NULL;
2179                         block->next_in_same_bio = NULL;
2180                 }
2181                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2182                         printk(KERN_INFO
2183                                "New written %c-block @%llu (%s/%llu/%d)\n",
2184                                is_metadata ? 'M' : 'D',
2185                                block->logical_bytenr, block->dev_state->name,
2186                                block->dev_bytenr, block->mirror_num);
2187                 list_add(&block->all_blocks_node, &state->all_blocks_list);
2188                 btrfsic_block_hashtable_add(block, &state->block_hashtable);
2189
2190                 if (is_metadata) {
2191                         ret = btrfsic_process_metablock(state, block,
2192                                                         &block_ctx, 0, 0);
2193                         if (ret)
2194                                 printk(KERN_INFO
2195                                        "btrfsic: process_metablock(root @%llu)"
2196                                        " failed!\n",
2197                                        dev_bytenr);
2198                 }
2199                 btrfsic_release_block_ctx(&block_ctx);
2200         }
2201
2202 continue_loop:
2203         BUG_ON(!processed_len);
2204         dev_bytenr += processed_len;
2205         mapped_datav += processed_len >> PAGE_CACHE_SHIFT;
2206         num_pages -= processed_len >> PAGE_CACHE_SHIFT;
2207         goto again;
2208 }
2209
2210 static void btrfsic_bio_end_io(struct bio *bp, int bio_error_status)
2211 {
2212         struct btrfsic_block *block = (struct btrfsic_block *)bp->bi_private;
2213         int iodone_w_error;
2214
2215         /* mutex is not held! This is not save if IO is not yet completed
2216          * on umount */
2217         iodone_w_error = 0;
2218         if (bio_error_status)
2219                 iodone_w_error = 1;
2220
2221         BUG_ON(NULL == block);
2222         bp->bi_private = block->orig_bio_bh_private;
2223         bp->bi_end_io = block->orig_bio_bh_end_io.bio;
2224
2225         do {
2226                 struct btrfsic_block *next_block;
2227                 struct btrfsic_dev_state *const dev_state = block->dev_state;
2228
2229                 if ((dev_state->state->print_mask &
2230                      BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2231                         printk(KERN_INFO
2232                                "bio_end_io(err=%d) for %c @%llu (%s/%llu/%d)\n",
2233                                bio_error_status,
2234                                btrfsic_get_block_type(dev_state->state, block),
2235                                block->logical_bytenr, dev_state->name,
2236                                block->dev_bytenr, block->mirror_num);
2237                 next_block = block->next_in_same_bio;
2238                 block->iodone_w_error = iodone_w_error;
2239                 if (block->submit_bio_bh_rw & REQ_FLUSH) {
2240                         dev_state->last_flush_gen++;
2241                         if ((dev_state->state->print_mask &
2242                              BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2243                                 printk(KERN_INFO
2244                                        "bio_end_io() new %s flush_gen=%llu\n",
2245                                        dev_state->name,
2246                                        dev_state->last_flush_gen);
2247                 }
2248                 if (block->submit_bio_bh_rw & REQ_FUA)
2249                         block->flush_gen = 0; /* FUA completed means block is
2250                                                * on disk */
2251                 block->is_iodone = 1; /* for FLUSH, this releases the block */
2252                 block = next_block;
2253         } while (NULL != block);
2254
2255         bp->bi_end_io(bp, bio_error_status);
2256 }
2257
2258 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate)
2259 {
2260         struct btrfsic_block *block = (struct btrfsic_block *)bh->b_private;
2261         int iodone_w_error = !uptodate;
2262         struct btrfsic_dev_state *dev_state;
2263
2264         BUG_ON(NULL == block);
2265         dev_state = block->dev_state;
2266         if ((dev_state->state->print_mask & BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2267                 printk(KERN_INFO
2268                        "bh_end_io(error=%d) for %c @%llu (%s/%llu/%d)\n",
2269                        iodone_w_error,
2270                        btrfsic_get_block_type(dev_state->state, block),
2271                        block->logical_bytenr, block->dev_state->name,
2272                        block->dev_bytenr, block->mirror_num);
2273
2274         block->iodone_w_error = iodone_w_error;
2275         if (block->submit_bio_bh_rw & REQ_FLUSH) {
2276                 dev_state->last_flush_gen++;
2277                 if ((dev_state->state->print_mask &
2278                      BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2279                         printk(KERN_INFO
2280                                "bh_end_io() new %s flush_gen=%llu\n",
2281                                dev_state->name, dev_state->last_flush_gen);
2282         }
2283         if (block->submit_bio_bh_rw & REQ_FUA)
2284                 block->flush_gen = 0; /* FUA completed means block is on disk */
2285
2286         bh->b_private = block->orig_bio_bh_private;
2287         bh->b_end_io = block->orig_bio_bh_end_io.bh;
2288         block->is_iodone = 1; /* for FLUSH, this releases the block */
2289         bh->b_end_io(bh, uptodate);
2290 }
2291
2292 static int btrfsic_process_written_superblock(
2293                 struct btrfsic_state *state,
2294                 struct btrfsic_block *const superblock,
2295                 struct btrfs_super_block *const super_hdr)
2296 {
2297         int pass;
2298
2299         superblock->generation = btrfs_super_generation(super_hdr);
2300         if (!(superblock->generation > state->max_superblock_generation ||
2301               0 == state->max_superblock_generation)) {
2302                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2303                         printk(KERN_INFO
2304                                "btrfsic: superblock @%llu (%s/%llu/%d)"
2305                                " with old gen %llu <= %llu\n",
2306                                superblock->logical_bytenr,
2307                                superblock->dev_state->name,
2308                                superblock->dev_bytenr, superblock->mirror_num,
2309                                btrfs_super_generation(super_hdr),
2310                                state->max_superblock_generation);
2311         } else {
2312                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2313                         printk(KERN_INFO
2314                                "btrfsic: got new superblock @%llu (%s/%llu/%d)"
2315                                " with new gen %llu > %llu\n",
2316                                superblock->logical_bytenr,
2317                                superblock->dev_state->name,
2318                                superblock->dev_bytenr, superblock->mirror_num,
2319                                btrfs_super_generation(super_hdr),
2320                                state->max_superblock_generation);
2321
2322                 state->max_superblock_generation =
2323                     btrfs_super_generation(super_hdr);
2324                 state->latest_superblock = superblock;
2325         }
2326
2327         for (pass = 0; pass < 3; pass++) {
2328                 int ret;
2329                 u64 next_bytenr;
2330                 struct btrfsic_block *next_block;
2331                 struct btrfsic_block_data_ctx tmp_next_block_ctx;
2332                 struct btrfsic_block_link *l;
2333                 int num_copies;
2334                 int mirror_num;
2335                 const char *additional_string = NULL;
2336                 struct btrfs_disk_key tmp_disk_key = {0};
2337
2338                 btrfs_set_disk_key_objectid(&tmp_disk_key,
2339                                             BTRFS_ROOT_ITEM_KEY);
2340                 btrfs_set_disk_key_objectid(&tmp_disk_key, 0);
2341
2342                 switch (pass) {
2343                 case 0:
2344                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2345                                                     BTRFS_ROOT_TREE_OBJECTID);
2346                         additional_string = "root ";
2347                         next_bytenr = btrfs_super_root(super_hdr);
2348                         if (state->print_mask &
2349                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2350                                 printk(KERN_INFO "root@%llu\n", next_bytenr);
2351                         break;
2352                 case 1:
2353                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2354                                                     BTRFS_CHUNK_TREE_OBJECTID);
2355                         additional_string = "chunk ";
2356                         next_bytenr = btrfs_super_chunk_root(super_hdr);
2357                         if (state->print_mask &
2358                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2359                                 printk(KERN_INFO "chunk@%llu\n", next_bytenr);
2360                         break;
2361                 case 2:
2362                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2363                                                     BTRFS_TREE_LOG_OBJECTID);
2364                         additional_string = "log ";
2365                         next_bytenr = btrfs_super_log_root(super_hdr);
2366                         if (0 == next_bytenr)
2367                                 continue;
2368                         if (state->print_mask &
2369                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2370                                 printk(KERN_INFO "log@%llu\n", next_bytenr);
2371                         break;
2372                 }
2373
2374                 num_copies =
2375                     btrfs_num_copies(state->root->fs_info,
2376                                      next_bytenr, BTRFS_SUPER_INFO_SIZE);
2377                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
2378                         printk(KERN_INFO "num_copies(log_bytenr=%llu) = %d\n",
2379                                next_bytenr, num_copies);
2380                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2381                         int was_created;
2382
2383                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2384                                 printk(KERN_INFO
2385                                        "btrfsic_process_written_superblock("
2386                                        "mirror_num=%d)\n", mirror_num);
2387                         ret = btrfsic_map_block(state, next_bytenr,
2388                                                 BTRFS_SUPER_INFO_SIZE,
2389                                                 &tmp_next_block_ctx,
2390                                                 mirror_num);
2391                         if (ret) {
2392                                 printk(KERN_INFO
2393                                        "btrfsic: btrfsic_map_block(@%llu,"
2394                                        " mirror=%d) failed!\n",
2395                                        next_bytenr, mirror_num);
2396                                 return -1;
2397                         }
2398
2399                         next_block = btrfsic_block_lookup_or_add(
2400                                         state,
2401                                         &tmp_next_block_ctx,
2402                                         additional_string,
2403                                         1, 0, 1,
2404                                         mirror_num,
2405                                         &was_created);
2406                         if (NULL == next_block) {
2407                                 printk(KERN_INFO
2408                                        "btrfsic: error, kmalloc failed!\n");
2409                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
2410                                 return -1;
2411                         }
2412
2413                         next_block->disk_key = tmp_disk_key;
2414                         if (was_created)
2415                                 next_block->generation =
2416                                     BTRFSIC_GENERATION_UNKNOWN;
2417                         l = btrfsic_block_link_lookup_or_add(
2418                                         state,
2419                                         &tmp_next_block_ctx,
2420                                         next_block,
2421                                         superblock,
2422                                         BTRFSIC_GENERATION_UNKNOWN);
2423                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
2424                         if (NULL == l)
2425                                 return -1;
2426                 }
2427         }
2428
2429         if (WARN_ON(-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)))
2430                 btrfsic_dump_tree(state);
2431
2432         return 0;
2433 }
2434
2435 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
2436                                         struct btrfsic_block *const block,
2437                                         int recursion_level)
2438 {
2439         struct list_head *elem_ref_to;
2440         int ret = 0;
2441
2442         if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2443                 /*
2444                  * Note that this situation can happen and does not
2445                  * indicate an error in regular cases. It happens
2446                  * when disk blocks are freed and later reused.
2447                  * The check-integrity module is not aware of any
2448                  * block free operations, it just recognizes block
2449                  * write operations. Therefore it keeps the linkage
2450                  * information for a block until a block is
2451                  * rewritten. This can temporarily cause incorrect
2452                  * and even circular linkage informations. This
2453                  * causes no harm unless such blocks are referenced
2454                  * by the most recent super block.
2455                  */
2456                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2457                         printk(KERN_INFO
2458                                "btrfsic: abort cyclic linkage (case 1).\n");
2459
2460                 return ret;
2461         }
2462
2463         /*
2464          * This algorithm is recursive because the amount of used stack
2465          * space is very small and the max recursion depth is limited.
2466          */
2467         list_for_each(elem_ref_to, &block->ref_to_list) {
2468                 const struct btrfsic_block_link *const l =
2469                     list_entry(elem_ref_to, struct btrfsic_block_link,
2470                                node_ref_to);
2471
2472                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2473                         printk(KERN_INFO
2474                                "rl=%d, %c @%llu (%s/%llu/%d)"
2475                                " %u* refers to %c @%llu (%s/%llu/%d)\n",
2476                                recursion_level,
2477                                btrfsic_get_block_type(state, block),
2478                                block->logical_bytenr, block->dev_state->name,
2479                                block->dev_bytenr, block->mirror_num,
2480                                l->ref_cnt,
2481                                btrfsic_get_block_type(state, l->block_ref_to),
2482                                l->block_ref_to->logical_bytenr,
2483                                l->block_ref_to->dev_state->name,
2484                                l->block_ref_to->dev_bytenr,
2485                                l->block_ref_to->mirror_num);
2486                 if (l->block_ref_to->never_written) {
2487                         printk(KERN_INFO "btrfs: attempt to write superblock"
2488                                " which references block %c @%llu (%s/%llu/%d)"
2489                                " which is never written!\n",
2490                                btrfsic_get_block_type(state, l->block_ref_to),
2491                                l->block_ref_to->logical_bytenr,
2492                                l->block_ref_to->dev_state->name,
2493                                l->block_ref_to->dev_bytenr,
2494                                l->block_ref_to->mirror_num);
2495                         ret = -1;
2496                 } else if (!l->block_ref_to->is_iodone) {
2497                         printk(KERN_INFO "btrfs: attempt to write superblock"
2498                                " which references block %c @%llu (%s/%llu/%d)"
2499                                " which is not yet iodone!\n",
2500                                btrfsic_get_block_type(state, l->block_ref_to),
2501                                l->block_ref_to->logical_bytenr,
2502                                l->block_ref_to->dev_state->name,
2503                                l->block_ref_to->dev_bytenr,
2504                                l->block_ref_to->mirror_num);
2505                         ret = -1;
2506                 } else if (l->block_ref_to->iodone_w_error) {
2507                         printk(KERN_INFO "btrfs: attempt to write superblock"
2508                                " which references block %c @%llu (%s/%llu/%d)"
2509                                " which has write error!\n",
2510                                btrfsic_get_block_type(state, l->block_ref_to),
2511                                l->block_ref_to->logical_bytenr,
2512                                l->block_ref_to->dev_state->name,
2513                                l->block_ref_to->dev_bytenr,
2514                                l->block_ref_to->mirror_num);
2515                         ret = -1;
2516                 } else if (l->parent_generation !=
2517                            l->block_ref_to->generation &&
2518                            BTRFSIC_GENERATION_UNKNOWN !=
2519                            l->parent_generation &&
2520                            BTRFSIC_GENERATION_UNKNOWN !=
2521                            l->block_ref_to->generation) {
2522                         printk(KERN_INFO "btrfs: attempt to write superblock"
2523                                " which references block %c @%llu (%s/%llu/%d)"
2524                                " with generation %llu !="
2525                                " parent generation %llu!\n",
2526                                btrfsic_get_block_type(state, l->block_ref_to),
2527                                l->block_ref_to->logical_bytenr,
2528                                l->block_ref_to->dev_state->name,
2529                                l->block_ref_to->dev_bytenr,
2530                                l->block_ref_to->mirror_num,
2531                                l->block_ref_to->generation,
2532                                l->parent_generation);
2533                         ret = -1;
2534                 } else if (l->block_ref_to->flush_gen >
2535                            l->block_ref_to->dev_state->last_flush_gen) {
2536                         printk(KERN_INFO "btrfs: attempt to write superblock"
2537                                " which references block %c @%llu (%s/%llu/%d)"
2538                                " which is not flushed out of disk's write cache"
2539                                " (block flush_gen=%llu,"
2540                                " dev->flush_gen=%llu)!\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, block->flush_gen,
2546                                l->block_ref_to->dev_state->last_flush_gen);
2547                         ret = -1;
2548                 } else if (-1 == btrfsic_check_all_ref_blocks(state,
2549                                                               l->block_ref_to,
2550                                                               recursion_level +
2551                                                               1)) {
2552                         ret = -1;
2553                 }
2554         }
2555
2556         return ret;
2557 }
2558
2559 static int btrfsic_is_block_ref_by_superblock(
2560                 const struct btrfsic_state *state,
2561                 const struct btrfsic_block *block,
2562                 int recursion_level)
2563 {
2564         struct list_head *elem_ref_from;
2565
2566         if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2567                 /* refer to comment at "abort cyclic linkage (case 1)" */
2568                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2569                         printk(KERN_INFO
2570                                "btrfsic: abort cyclic linkage (case 2).\n");
2571
2572                 return 0;
2573         }
2574
2575         /*
2576          * This algorithm is recursive because the amount of used stack space
2577          * is very small and the max recursion depth is limited.
2578          */
2579         list_for_each(elem_ref_from, &block->ref_from_list) {
2580                 const struct btrfsic_block_link *const l =
2581                     list_entry(elem_ref_from, struct btrfsic_block_link,
2582                                node_ref_from);
2583
2584                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2585                         printk(KERN_INFO
2586                                "rl=%d, %c @%llu (%s/%llu/%d)"
2587                                " is ref %u* from %c @%llu (%s/%llu/%d)\n",
2588                                recursion_level,
2589                                btrfsic_get_block_type(state, block),
2590                                block->logical_bytenr, block->dev_state->name,
2591                                block->dev_bytenr, block->mirror_num,
2592                                l->ref_cnt,
2593                                btrfsic_get_block_type(state, l->block_ref_from),
2594                                l->block_ref_from->logical_bytenr,
2595                                l->block_ref_from->dev_state->name,
2596                                l->block_ref_from->dev_bytenr,
2597                                l->block_ref_from->mirror_num);
2598                 if (l->block_ref_from->is_superblock &&
2599                     state->latest_superblock->dev_bytenr ==
2600                     l->block_ref_from->dev_bytenr &&
2601                     state->latest_superblock->dev_state->bdev ==
2602                     l->block_ref_from->dev_state->bdev)
2603                         return 1;
2604                 else if (btrfsic_is_block_ref_by_superblock(state,
2605                                                             l->block_ref_from,
2606                                                             recursion_level +
2607                                                             1))
2608                         return 1;
2609         }
2610
2611         return 0;
2612 }
2613
2614 static void btrfsic_print_add_link(const struct btrfsic_state *state,
2615                                    const struct btrfsic_block_link *l)
2616 {
2617         printk(KERN_INFO
2618                "Add %u* link from %c @%llu (%s/%llu/%d)"
2619                " to %c @%llu (%s/%llu/%d).\n",
2620                l->ref_cnt,
2621                btrfsic_get_block_type(state, l->block_ref_from),
2622                l->block_ref_from->logical_bytenr,
2623                l->block_ref_from->dev_state->name,
2624                l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2625                btrfsic_get_block_type(state, l->block_ref_to),
2626                l->block_ref_to->logical_bytenr,
2627                l->block_ref_to->dev_state->name, l->block_ref_to->dev_bytenr,
2628                l->block_ref_to->mirror_num);
2629 }
2630
2631 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
2632                                    const struct btrfsic_block_link *l)
2633 {
2634         printk(KERN_INFO
2635                "Rem %u* link from %c @%llu (%s/%llu/%d)"
2636                " to %c @%llu (%s/%llu/%d).\n",
2637                l->ref_cnt,
2638                btrfsic_get_block_type(state, l->block_ref_from),
2639                l->block_ref_from->logical_bytenr,
2640                l->block_ref_from->dev_state->name,
2641                l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2642                btrfsic_get_block_type(state, l->block_ref_to),
2643                l->block_ref_to->logical_bytenr,
2644                l->block_ref_to->dev_state->name, l->block_ref_to->dev_bytenr,
2645                l->block_ref_to->mirror_num);
2646 }
2647
2648 static char btrfsic_get_block_type(const struct btrfsic_state *state,
2649                                    const struct btrfsic_block *block)
2650 {
2651         if (block->is_superblock &&
2652             state->latest_superblock->dev_bytenr == block->dev_bytenr &&
2653             state->latest_superblock->dev_state->bdev == block->dev_state->bdev)
2654                 return 'S';
2655         else if (block->is_superblock)
2656                 return 's';
2657         else if (block->is_metadata)
2658                 return 'M';
2659         else
2660                 return 'D';
2661 }
2662
2663 static void btrfsic_dump_tree(const struct btrfsic_state *state)
2664 {
2665         btrfsic_dump_tree_sub(state, state->latest_superblock, 0);
2666 }
2667
2668 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
2669                                   const struct btrfsic_block *block,
2670                                   int indent_level)
2671 {
2672         struct list_head *elem_ref_to;
2673         int indent_add;
2674         static char buf[80];
2675         int cursor_position;
2676
2677         /*
2678          * Should better fill an on-stack buffer with a complete line and
2679          * dump it at once when it is time to print a newline character.
2680          */
2681
2682         /*
2683          * This algorithm is recursive because the amount of used stack space
2684          * is very small and the max recursion depth is limited.
2685          */
2686         indent_add = sprintf(buf, "%c-%llu(%s/%llu/%d)",
2687                              btrfsic_get_block_type(state, block),
2688                              block->logical_bytenr, block->dev_state->name,
2689                              block->dev_bytenr, block->mirror_num);
2690         if (indent_level + indent_add > BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2691                 printk("[...]\n");
2692                 return;
2693         }
2694         printk(buf);
2695         indent_level += indent_add;
2696         if (list_empty(&block->ref_to_list)) {
2697                 printk("\n");
2698                 return;
2699         }
2700         if (block->mirror_num > 1 &&
2701             !(state->print_mask & BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS)) {
2702                 printk(" [...]\n");
2703                 return;
2704         }
2705
2706         cursor_position = indent_level;
2707         list_for_each(elem_ref_to, &block->ref_to_list) {
2708                 const struct btrfsic_block_link *const l =
2709                     list_entry(elem_ref_to, struct btrfsic_block_link,
2710                                node_ref_to);
2711
2712                 while (cursor_position < indent_level) {
2713                         printk(" ");
2714                         cursor_position++;
2715                 }
2716                 if (l->ref_cnt > 1)
2717                         indent_add = sprintf(buf, " %d*--> ", l->ref_cnt);
2718                 else
2719                         indent_add = sprintf(buf, " --> ");
2720                 if (indent_level + indent_add >
2721                     BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2722                         printk("[...]\n");
2723                         cursor_position = 0;
2724                         continue;
2725                 }
2726
2727                 printk(buf);
2728
2729                 btrfsic_dump_tree_sub(state, l->block_ref_to,
2730                                       indent_level + indent_add);
2731                 cursor_position = 0;
2732         }
2733 }
2734
2735 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
2736                 struct btrfsic_state *state,
2737                 struct btrfsic_block_data_ctx *next_block_ctx,
2738                 struct btrfsic_block *next_block,
2739                 struct btrfsic_block *from_block,
2740                 u64 parent_generation)
2741 {
2742         struct btrfsic_block_link *l;
2743
2744         l = btrfsic_block_link_hashtable_lookup(next_block_ctx->dev->bdev,
2745                                                 next_block_ctx->dev_bytenr,
2746                                                 from_block->dev_state->bdev,
2747                                                 from_block->dev_bytenr,
2748                                                 &state->block_link_hashtable);
2749         if (NULL == l) {
2750                 l = btrfsic_block_link_alloc();
2751                 if (NULL == l) {
2752                         printk(KERN_INFO
2753                                "btrfsic: error, kmalloc" " failed!\n");
2754                         return NULL;
2755                 }
2756
2757                 l->block_ref_to = next_block;
2758                 l->block_ref_from = from_block;
2759                 l->ref_cnt = 1;
2760                 l->parent_generation = parent_generation;
2761
2762                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2763                         btrfsic_print_add_link(state, l);
2764
2765                 list_add(&l->node_ref_to, &from_block->ref_to_list);
2766                 list_add(&l->node_ref_from, &next_block->ref_from_list);
2767
2768                 btrfsic_block_link_hashtable_add(l,
2769                                                  &state->block_link_hashtable);
2770         } else {
2771                 l->ref_cnt++;
2772                 l->parent_generation = parent_generation;
2773                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2774                         btrfsic_print_add_link(state, l);
2775         }
2776
2777         return l;
2778 }
2779
2780 static struct btrfsic_block *btrfsic_block_lookup_or_add(
2781                 struct btrfsic_state *state,
2782                 struct btrfsic_block_data_ctx *block_ctx,
2783                 const char *additional_string,
2784                 int is_metadata,
2785                 int is_iodone,
2786                 int never_written,
2787                 int mirror_num,
2788                 int *was_created)
2789 {
2790         struct btrfsic_block *block;
2791
2792         block = btrfsic_block_hashtable_lookup(block_ctx->dev->bdev,
2793                                                block_ctx->dev_bytenr,
2794                                                &state->block_hashtable);
2795         if (NULL == block) {
2796                 struct btrfsic_dev_state *dev_state;
2797
2798                 block = btrfsic_block_alloc();
2799                 if (NULL == block) {
2800                         printk(KERN_INFO "btrfsic: error, kmalloc failed!\n");
2801                         return NULL;
2802                 }
2803                 dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev);
2804                 if (NULL == dev_state) {
2805                         printk(KERN_INFO
2806                                "btrfsic: error, lookup dev_state failed!\n");
2807                         btrfsic_block_free(block);
2808                         return NULL;
2809                 }
2810                 block->dev_state = dev_state;
2811                 block->dev_bytenr = block_ctx->dev_bytenr;
2812                 block->logical_bytenr = block_ctx->start;
2813                 block->is_metadata = is_metadata;
2814                 block->is_iodone = is_iodone;
2815                 block->never_written = never_written;
2816                 block->mirror_num = mirror_num;
2817                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2818                         printk(KERN_INFO
2819                                "New %s%c-block @%llu (%s/%llu/%d)\n",
2820                                additional_string,
2821                                btrfsic_get_block_type(state, block),
2822                                block->logical_bytenr, dev_state->name,
2823                                block->dev_bytenr, mirror_num);
2824                 list_add(&block->all_blocks_node, &state->all_blocks_list);
2825                 btrfsic_block_hashtable_add(block, &state->block_hashtable);
2826                 if (NULL != was_created)
2827                         *was_created = 1;
2828         } else {
2829                 if (NULL != was_created)
2830                         *was_created = 0;
2831         }
2832
2833         return block;
2834 }
2835
2836 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
2837                                            u64 bytenr,
2838                                            struct btrfsic_dev_state *dev_state,
2839                                            u64 dev_bytenr)
2840 {
2841         int num_copies;
2842         int mirror_num;
2843         int ret;
2844         struct btrfsic_block_data_ctx block_ctx;
2845         int match = 0;
2846
2847         num_copies = btrfs_num_copies(state->root->fs_info,
2848                                       bytenr, state->metablock_size);
2849
2850         for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2851                 ret = btrfsic_map_block(state, bytenr, state->metablock_size,
2852                                         &block_ctx, mirror_num);
2853                 if (ret) {
2854                         printk(KERN_INFO "btrfsic:"
2855                                " btrfsic_map_block(logical @%llu,"
2856                                " mirror %d) failed!\n",
2857                                bytenr, mirror_num);
2858                         continue;
2859                 }
2860
2861                 if (dev_state->bdev == block_ctx.dev->bdev &&
2862                     dev_bytenr == block_ctx.dev_bytenr) {
2863                         match++;
2864                         btrfsic_release_block_ctx(&block_ctx);
2865                         break;
2866                 }
2867                 btrfsic_release_block_ctx(&block_ctx);
2868         }
2869
2870         if (WARN_ON(!match)) {
2871                 printk(KERN_INFO "btrfs: attempt to write M-block which contains logical bytenr that doesn't map to dev+physical bytenr of submit_bio,"
2872                        " buffer->log_bytenr=%llu, submit_bio(bdev=%s,"
2873                        " phys_bytenr=%llu)!\n",
2874                        bytenr, dev_state->name, dev_bytenr);
2875                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2876                         ret = btrfsic_map_block(state, bytenr,
2877                                                 state->metablock_size,
2878                                                 &block_ctx, mirror_num);
2879                         if (ret)
2880                                 continue;
2881
2882                         printk(KERN_INFO "Read logical bytenr @%llu maps to"
2883                                " (%s/%llu/%d)\n",
2884                                bytenr, block_ctx.dev->name,
2885                                block_ctx.dev_bytenr, mirror_num);
2886                 }
2887         }
2888 }
2889
2890 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(
2891                 struct block_device *bdev)
2892 {
2893         struct btrfsic_dev_state *ds;
2894
2895         ds = btrfsic_dev_state_hashtable_lookup(bdev,
2896                                                 &btrfsic_dev_state_hashtable);
2897         return ds;
2898 }
2899
2900 int btrfsic_submit_bh(int rw, struct buffer_head *bh)
2901 {
2902         struct btrfsic_dev_state *dev_state;
2903
2904         if (!btrfsic_is_initialized)
2905                 return submit_bh(rw, bh);
2906
2907         mutex_lock(&btrfsic_mutex);
2908         /* since btrfsic_submit_bh() might also be called before
2909          * btrfsic_mount(), this might return NULL */
2910         dev_state = btrfsic_dev_state_lookup(bh->b_bdev);
2911
2912         /* Only called to write the superblock (incl. FLUSH/FUA) */
2913         if (NULL != dev_state &&
2914             (rw & WRITE) && bh->b_size > 0) {
2915                 u64 dev_bytenr;
2916
2917                 dev_bytenr = 4096 * bh->b_blocknr;
2918                 if (dev_state->state->print_mask &
2919                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2920                         printk(KERN_INFO
2921                                "submit_bh(rw=0x%x, blocknr=%llu (bytenr %llu),"
2922                                " size=%zu, data=%p, bdev=%p)\n",
2923                                rw, (unsigned long long)bh->b_blocknr,
2924                                dev_bytenr, bh->b_size, bh->b_data, bh->b_bdev);
2925                 btrfsic_process_written_block(dev_state, dev_bytenr,
2926                                               &bh->b_data, 1, NULL,
2927                                               NULL, bh, rw);
2928         } else if (NULL != dev_state && (rw & REQ_FLUSH)) {
2929                 if (dev_state->state->print_mask &
2930                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2931                         printk(KERN_INFO
2932                                "submit_bh(rw=0x%x FLUSH, bdev=%p)\n",
2933                                rw, bh->b_bdev);
2934                 if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
2935                         if ((dev_state->state->print_mask &
2936                              (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2937                               BTRFSIC_PRINT_MASK_VERBOSE)))
2938                                 printk(KERN_INFO
2939                                        "btrfsic_submit_bh(%s) with FLUSH"
2940                                        " but dummy block already in use"
2941                                        " (ignored)!\n",
2942                                        dev_state->name);
2943                 } else {
2944                         struct btrfsic_block *const block =
2945                                 &dev_state->dummy_block_for_bio_bh_flush;
2946
2947                         block->is_iodone = 0;
2948                         block->never_written = 0;
2949                         block->iodone_w_error = 0;
2950                         block->flush_gen = dev_state->last_flush_gen + 1;
2951                         block->submit_bio_bh_rw = rw;
2952                         block->orig_bio_bh_private = bh->b_private;
2953                         block->orig_bio_bh_end_io.bh = bh->b_end_io;
2954                         block->next_in_same_bio = NULL;
2955                         bh->b_private = block;
2956                         bh->b_end_io = btrfsic_bh_end_io;
2957                 }
2958         }
2959         mutex_unlock(&btrfsic_mutex);
2960         return submit_bh(rw, bh);
2961 }
2962
2963 static void __btrfsic_submit_bio(int rw, struct bio *bio)
2964 {
2965         struct btrfsic_dev_state *dev_state;
2966
2967         if (!btrfsic_is_initialized)
2968                 return;
2969
2970         mutex_lock(&btrfsic_mutex);
2971         /* since btrfsic_submit_bio() is also called before
2972          * btrfsic_mount(), this might return NULL */
2973         dev_state = btrfsic_dev_state_lookup(bio->bi_bdev);
2974         if (NULL != dev_state &&
2975             (rw & WRITE) && NULL != bio->bi_io_vec) {
2976                 unsigned int i;
2977                 u64 dev_bytenr;
2978                 u64 cur_bytenr;
2979                 int bio_is_patched;
2980                 char **mapped_datav;
2981
2982                 dev_bytenr = 512 * bio->bi_iter.bi_sector;
2983                 bio_is_patched = 0;
2984                 if (dev_state->state->print_mask &
2985                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2986                         printk(KERN_INFO
2987                                "submit_bio(rw=0x%x, bi_vcnt=%u,"
2988                                " bi_sector=%llu (bytenr %llu), bi_bdev=%p)\n",
2989                                rw, bio->bi_vcnt,
2990                                (unsigned long long)bio->bi_iter.bi_sector,
2991                                dev_bytenr, bio->bi_bdev);
2992
2993                 mapped_datav = kmalloc_array(bio->bi_vcnt,
2994                                              sizeof(*mapped_datav), GFP_NOFS);
2995                 if (!mapped_datav)
2996                         goto leave;
2997                 cur_bytenr = dev_bytenr;
2998                 for (i = 0; i < bio->bi_vcnt; i++) {
2999                         BUG_ON(bio->bi_io_vec[i].bv_len != PAGE_CACHE_SIZE);
3000                         mapped_datav[i] = kmap(bio->bi_io_vec[i].bv_page);
3001                         if (!mapped_datav[i]) {
3002                                 while (i > 0) {
3003                                         i--;
3004                                         kunmap(bio->bi_io_vec[i].bv_page);
3005                                 }
3006                                 kfree(mapped_datav);
3007                                 goto leave;
3008                         }
3009                         if (dev_state->state->print_mask &
3010                             BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE)
3011                                 printk(KERN_INFO
3012                                        "#%u: bytenr=%llu, len=%u, offset=%u\n",
3013                                        i, cur_bytenr, bio->bi_io_vec[i].bv_len,
3014                                        bio->bi_io_vec[i].bv_offset);
3015                         cur_bytenr += bio->bi_io_vec[i].bv_len;
3016                 }
3017                 btrfsic_process_written_block(dev_state, dev_bytenr,
3018                                               mapped_datav, bio->bi_vcnt,
3019                                               bio, &bio_is_patched,
3020                                               NULL, rw);
3021                 while (i > 0) {
3022                         i--;
3023                         kunmap(bio->bi_io_vec[i].bv_page);
3024                 }
3025                 kfree(mapped_datav);
3026         } else if (NULL != dev_state && (rw & REQ_FLUSH)) {
3027                 if (dev_state->state->print_mask &
3028                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
3029                         printk(KERN_INFO
3030                                "submit_bio(rw=0x%x FLUSH, bdev=%p)\n",
3031                                rw, bio->bi_bdev);
3032                 if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
3033                         if ((dev_state->state->print_mask &
3034                              (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
3035                               BTRFSIC_PRINT_MASK_VERBOSE)))
3036                                 printk(KERN_INFO
3037                                        "btrfsic_submit_bio(%s) with FLUSH"
3038                                        " but dummy block already in use"
3039                                        " (ignored)!\n",
3040                                        dev_state->name);
3041                 } else {
3042                         struct btrfsic_block *const block =
3043                                 &dev_state->dummy_block_for_bio_bh_flush;
3044
3045                         block->is_iodone = 0;
3046                         block->never_written = 0;
3047                         block->iodone_w_error = 0;
3048                         block->flush_gen = dev_state->last_flush_gen + 1;
3049                         block->submit_bio_bh_rw = rw;
3050                         block->orig_bio_bh_private = bio->bi_private;
3051                         block->orig_bio_bh_end_io.bio = bio->bi_end_io;
3052                         block->next_in_same_bio = NULL;
3053                         bio->bi_private = block;
3054                         bio->bi_end_io = btrfsic_bio_end_io;
3055                 }
3056         }
3057 leave:
3058         mutex_unlock(&btrfsic_mutex);
3059 }
3060
3061 void btrfsic_submit_bio(int rw, struct bio *bio)
3062 {
3063         __btrfsic_submit_bio(rw, bio);
3064         submit_bio(rw, bio);
3065 }
3066
3067 int btrfsic_submit_bio_wait(int rw, struct bio *bio)
3068 {
3069         __btrfsic_submit_bio(rw, bio);
3070         return submit_bio_wait(rw, bio);
3071 }
3072
3073 int btrfsic_mount(struct btrfs_root *root,
3074                   struct btrfs_fs_devices *fs_devices,
3075                   int including_extent_data, u32 print_mask)
3076 {
3077         int ret;
3078         struct btrfsic_state *state;
3079         struct list_head *dev_head = &fs_devices->devices;
3080         struct btrfs_device *device;
3081
3082         if (root->nodesize & ((u64)PAGE_CACHE_SIZE - 1)) {
3083                 printk(KERN_INFO
3084                        "btrfsic: cannot handle nodesize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3085                        root->nodesize, PAGE_CACHE_SIZE);
3086                 return -1;
3087         }
3088         if (root->sectorsize & ((u64)PAGE_CACHE_SIZE - 1)) {
3089                 printk(KERN_INFO
3090                        "btrfsic: cannot handle sectorsize %d not being a multiple of PAGE_CACHE_SIZE %ld!\n",
3091                        root->sectorsize, PAGE_CACHE_SIZE);
3092                 return -1;
3093         }
3094         state = kzalloc(sizeof(*state), GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT);
3095         if (!state) {
3096                 state = vzalloc(sizeof(*state));
3097                 if (!state) {
3098                         printk(KERN_INFO "btrfs check-integrity: vzalloc() failed!\n");
3099                         return -1;
3100                 }
3101         }
3102
3103         if (!btrfsic_is_initialized) {
3104                 mutex_init(&btrfsic_mutex);
3105                 btrfsic_dev_state_hashtable_init(&btrfsic_dev_state_hashtable);
3106                 btrfsic_is_initialized = 1;
3107         }
3108         mutex_lock(&btrfsic_mutex);
3109         state->root = root;
3110         state->print_mask = print_mask;
3111         state->include_extent_data = including_extent_data;
3112         state->csum_size = 0;
3113         state->metablock_size = root->nodesize;
3114         state->datablock_size = root->sectorsize;
3115         INIT_LIST_HEAD(&state->all_blocks_list);
3116         btrfsic_block_hashtable_init(&state->block_hashtable);
3117         btrfsic_block_link_hashtable_init(&state->block_link_hashtable);
3118         state->max_superblock_generation = 0;
3119         state->latest_superblock = NULL;
3120
3121         list_for_each_entry(device, dev_head, dev_list) {
3122                 struct btrfsic_dev_state *ds;
3123                 char *p;
3124
3125                 if (!device->bdev || !device->name)
3126                         continue;
3127
3128                 ds = btrfsic_dev_state_alloc();
3129                 if (NULL == ds) {
3130                         printk(KERN_INFO
3131                                "btrfs check-integrity: kmalloc() failed!\n");
3132                         mutex_unlock(&btrfsic_mutex);
3133                         return -1;
3134                 }
3135                 ds->bdev = device->bdev;
3136                 ds->state = state;
3137                 bdevname(ds->bdev, ds->name);
3138                 ds->name[BDEVNAME_SIZE - 1] = '\0';
3139                 for (p = ds->name; *p != '\0'; p++);
3140                 while (p > ds->name && *p != '/')
3141                         p--;
3142                 if (*p == '/')
3143                         p++;
3144                 strlcpy(ds->name, p, sizeof(ds->name));
3145                 btrfsic_dev_state_hashtable_add(ds,
3146                                                 &btrfsic_dev_state_hashtable);
3147         }
3148
3149         ret = btrfsic_process_superblock(state, fs_devices);
3150         if (0 != ret) {
3151                 mutex_unlock(&btrfsic_mutex);
3152                 btrfsic_unmount(root, fs_devices);
3153                 return ret;
3154         }
3155
3156         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_DATABASE)
3157                 btrfsic_dump_database(state);
3158         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_TREE)
3159                 btrfsic_dump_tree(state);
3160
3161         mutex_unlock(&btrfsic_mutex);
3162         return 0;
3163 }
3164
3165 void btrfsic_unmount(struct btrfs_root *root,
3166                      struct btrfs_fs_devices *fs_devices)
3167 {
3168         struct list_head *elem_all;
3169         struct list_head *tmp_all;
3170         struct btrfsic_state *state;
3171         struct list_head *dev_head = &fs_devices->devices;
3172         struct btrfs_device *device;
3173
3174         if (!btrfsic_is_initialized)
3175                 return;
3176
3177         mutex_lock(&btrfsic_mutex);
3178
3179         state = NULL;
3180         list_for_each_entry(device, dev_head, dev_list) {
3181                 struct btrfsic_dev_state *ds;
3182
3183                 if (!device->bdev || !device->name)
3184                         continue;
3185
3186                 ds = btrfsic_dev_state_hashtable_lookup(
3187                                 device->bdev,
3188                                 &btrfsic_dev_state_hashtable);
3189                 if (NULL != ds) {
3190                         state = ds->state;
3191                         btrfsic_dev_state_hashtable_remove(ds);
3192                         btrfsic_dev_state_free(ds);
3193                 }
3194         }
3195
3196         if (NULL == state) {
3197                 printk(KERN_INFO
3198                        "btrfsic: error, cannot find state information"
3199                        " on umount!\n");
3200                 mutex_unlock(&btrfsic_mutex);
3201                 return;
3202         }
3203
3204         /*
3205          * Don't care about keeping the lists' state up to date,
3206          * just free all memory that was allocated dynamically.
3207          * Free the blocks and the block_links.
3208          */
3209         list_for_each_safe(elem_all, tmp_all, &state->all_blocks_list) {
3210                 struct btrfsic_block *const b_all =
3211                     list_entry(elem_all, struct btrfsic_block,
3212                                all_blocks_node);
3213                 struct list_head *elem_ref_to;
3214                 struct list_head *tmp_ref_to;
3215
3216                 list_for_each_safe(elem_ref_to, tmp_ref_to,
3217                                    &b_all->ref_to_list) {
3218                         struct btrfsic_block_link *const l =
3219                             list_entry(elem_ref_to,
3220                                        struct btrfsic_block_link,
3221                                        node_ref_to);
3222
3223                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
3224                                 btrfsic_print_rem_link(state, l);
3225
3226                         l->ref_cnt--;
3227                         if (0 == l->ref_cnt)
3228                                 btrfsic_block_link_free(l);
3229                 }
3230
3231                 if (b_all->is_iodone || b_all->never_written)
3232                         btrfsic_block_free(b_all);
3233                 else
3234                         printk(KERN_INFO "btrfs: attempt to free %c-block"
3235                                " @%llu (%s/%llu/%d) on umount which is"
3236                                " not yet iodone!\n",
3237                                btrfsic_get_block_type(state, b_all),
3238                                b_all->logical_bytenr, b_all->dev_state->name,
3239                                b_all->dev_bytenr, b_all->mirror_num);
3240         }
3241
3242         mutex_unlock(&btrfsic_mutex);
3243
3244         kvfree(state);
3245 }