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/mm.h>
  98 #include <linux/string.h>
  99 #include "ctree.h"
 100 #include "disk-io.h"
 101 #include "hash.h"
 102 #include "transaction.h"
 103 #include "extent_io.h"
 104 #include "volumes.h"
 105 #include "print-tree.h"
 106 #include "locking.h"
 107 #include "check-integrity.h"
 108 #include "rcu-string.h"
 109 #include "compression.h"
 110
 111 #define BTRFSIC_BLOCK_HASHTABLE_SIZE 0x10000
 112 #define BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE 0x10000
 113 #define BTRFSIC_DEV2STATE_HASHTABLE_SIZE 0x100
 114 #define BTRFSIC_BLOCK_MAGIC_NUMBER 0x14491051
 115 #define BTRFSIC_BLOCK_LINK_MAGIC_NUMBER 0x11070807
 116 #define BTRFSIC_DEV2STATE_MAGIC_NUMBER 0x20111530
 117 #define BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER 20111300
 118 #define BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL (200 - 6)    /* in characters,
 119                                                          * excluding " [...]" */
 120 #define BTRFSIC_GENERATION_UNKNOWN ((u64)-1)
 121
 122 /*
 123  * The definition of the bitmask fields for the print_mask.
 124  * They are specified with the mount option check_integrity_print_mask.
 125  */
 126 #define BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE                     0x00000001
 127 #define BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION         0x00000002
 128 #define BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE                  0x00000004
 129 #define BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE                 0x00000008
 130 #define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH                        0x00000010
 131 #define BTRFSIC_PRINT_MASK_END_IO_BIO_BH                        0x00000020
 132 #define BTRFSIC_PRINT_MASK_VERBOSE                              0x00000040
 133 #define BTRFSIC_PRINT_MASK_VERY_VERBOSE                         0x00000080
 134 #define BTRFSIC_PRINT_MASK_INITIAL_TREE                         0x00000100
 135 #define BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES                    0x00000200
 136 #define BTRFSIC_PRINT_MASK_INITIAL_DATABASE                     0x00000400
 137 #define BTRFSIC_PRINT_MASK_NUM_COPIES                           0x00000800
 138 #define BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS                0x00001000
 139 #define BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE                0x00002000
 140
 141 struct btrfsic_dev_state;
 142 struct btrfsic_state;
 143
 144 struct btrfsic_block {
 145         u32 magic_num;          /* only used for debug purposes */
 146         unsigned int is_metadata:1;     /* if it is meta-data, not data-data */
 147         unsigned int is_superblock:1;   /* if it is one of the superblocks */
 148         unsigned int is_iodone:1;       /* if is done by lower subsystem */
 149         unsigned int iodone_w_error:1;  /* error was indicated to endio */
 150         unsigned int never_written:1;   /* block was added because it was
 151                                          * referenced, not because it was
 152                                          * written */
 153         unsigned int mirror_num;        /* large enough to hold
 154                                          * BTRFS_SUPER_MIRROR_MAX */
 155         struct btrfsic_dev_state *dev_state;
 156         u64 dev_bytenr;         /* key, physical byte num on disk */
 157         u64 logical_bytenr;     /* logical byte num on disk */
 158         u64 generation;
 159         struct btrfs_disk_key disk_key; /* extra info to print in case of
 160                                          * issues, will not always be correct */
 161         struct list_head collision_resolving_node;      /* list node */
 162         struct list_head all_blocks_node;       /* list node */
 163
 164         /* the following two lists contain block_link items */
 165         struct list_head ref_to_list;   /* list */
 166         struct list_head ref_from_list; /* list */
 167         struct btrfsic_block *next_in_same_bio;
 168         void *orig_bio_bh_private;
 169         union {
 170                 bio_end_io_t *bio;
 171                 bh_end_io_t *bh;
 172         } orig_bio_bh_end_io;
 173         int submit_bio_bh_rw;
 174         u64 flush_gen; /* only valid if !never_written */
 175 };
 176
 177 /*
 178  * Elements of this type are allocated dynamically and required because
 179  * each block object can refer to and can be ref from multiple blocks.
 180  * The key to lookup them in the hashtable is the dev_bytenr of
 181  * the block ref to plus the one from the block referred from.
 182  * The fact that they are searchable via a hashtable and that a
 183  * ref_cnt is maintained is not required for the btrfs integrity
 184  * check algorithm itself, it is only used to make the output more
 185  * beautiful in case that an error is detected (an error is defined
 186  * as a write operation to a block while that block is still referenced).
 187  */
 188 struct btrfsic_block_link {
 189         u32 magic_num;          /* only used for debug purposes */
 190         u32 ref_cnt;
 191         struct list_head node_ref_to;   /* list node */
 192         struct list_head node_ref_from; /* list node */
 193         struct list_head collision_resolving_node;      /* list node */
 194         struct btrfsic_block *block_ref_to;
 195         struct btrfsic_block *block_ref_from;
 196         u64 parent_generation;
 197 };
 198
 199 struct btrfsic_dev_state {
 200         u32 magic_num;          /* only used for debug purposes */
 201         struct block_device *bdev;
 202         struct btrfsic_state *state;
 203         struct list_head collision_resolving_node;      /* list node */
 204         struct btrfsic_block dummy_block_for_bio_bh_flush;
 205         u64 last_flush_gen;
 206         char name[BDEVNAME_SIZE];
 207 };
 208
 209 struct btrfsic_block_hashtable {
 210         struct list_head table[BTRFSIC_BLOCK_HASHTABLE_SIZE];
 211 };
 212
 213 struct btrfsic_block_link_hashtable {
 214         struct list_head table[BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE];
 215 };
 216
 217 struct btrfsic_dev_state_hashtable {
 218         struct list_head table[BTRFSIC_DEV2STATE_HASHTABLE_SIZE];
 219 };
 220
 221 struct btrfsic_block_data_ctx {
 222         u64 start;              /* virtual bytenr */
 223         u64 dev_bytenr;         /* physical bytenr on device */
 224         u32 len;
 225         struct btrfsic_dev_state *dev;
 226         char **datav;
 227         struct page **pagev;
 228         void *mem_to_free;
 229 };
 230
 231 /* This structure is used to implement recursion without occupying
 232  * any stack space, refer to btrfsic_process_metablock() */
 233 struct btrfsic_stack_frame {
 234         u32 magic;
 235         u32 nr;
 236         int error;
 237         int i;
 238         int limit_nesting;
 239         int num_copies;
 240         int mirror_num;
 241         struct btrfsic_block *block;
 242         struct btrfsic_block_data_ctx *block_ctx;
 243         struct btrfsic_block *next_block;
 244         struct btrfsic_block_data_ctx next_block_ctx;
 245         struct btrfs_header *hdr;
 246         struct btrfsic_stack_frame *prev;
 247 };
 248
 249 /* Some state per mounted filesystem */
 250 struct btrfsic_state {
 251         u32 print_mask;
 252         int include_extent_data;
 253         int csum_size;
 254         struct list_head all_blocks_list;
 255         struct btrfsic_block_hashtable block_hashtable;
 256         struct btrfsic_block_link_hashtable block_link_hashtable;
 257         struct btrfs_fs_info *fs_info;
 258         u64 max_superblock_generation;
 259         struct btrfsic_block *latest_superblock;
 260         u32 metablock_size;
 261         u32 datablock_size;
 262 };
 263
 264 static void btrfsic_block_init(struct btrfsic_block *b);
 265 static struct btrfsic_block *btrfsic_block_alloc(void);
 266 static void btrfsic_block_free(struct btrfsic_block *b);
 267 static void btrfsic_block_link_init(struct btrfsic_block_link *n);
 268 static struct btrfsic_block_link *btrfsic_block_link_alloc(void);
 269 static void btrfsic_block_link_free(struct btrfsic_block_link *n);
 270 static void btrfsic_dev_state_init(struct btrfsic_dev_state *ds);
 271 static struct btrfsic_dev_state *btrfsic_dev_state_alloc(void);
 272 static void btrfsic_dev_state_free(struct btrfsic_dev_state *ds);
 273 static void btrfsic_block_hashtable_init(struct btrfsic_block_hashtable *h);
 274 static void btrfsic_block_hashtable_add(struct btrfsic_block *b,
 275                                         struct btrfsic_block_hashtable *h);
 276 static void btrfsic_block_hashtable_remove(struct btrfsic_block *b);
 277 static struct btrfsic_block *btrfsic_block_hashtable_lookup(
 278                 struct block_device *bdev,
 279                 u64 dev_bytenr,
 280                 struct btrfsic_block_hashtable *h);
 281 static void btrfsic_block_link_hashtable_init(
 282                 struct btrfsic_block_link_hashtable *h);
 283 static void btrfsic_block_link_hashtable_add(
 284                 struct btrfsic_block_link *l,
 285                 struct btrfsic_block_link_hashtable *h);
 286 static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l);
 287 static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
 288                 struct block_device *bdev_ref_to,
 289                 u64 dev_bytenr_ref_to,
 290                 struct block_device *bdev_ref_from,
 291                 u64 dev_bytenr_ref_from,
 292                 struct btrfsic_block_link_hashtable *h);
 293 static void btrfsic_dev_state_hashtable_init(
 294                 struct btrfsic_dev_state_hashtable *h);
 295 static void btrfsic_dev_state_hashtable_add(
 296                 struct btrfsic_dev_state *ds,
 297                 struct btrfsic_dev_state_hashtable *h);
 298 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds);
 299 static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(dev_t dev,
 300                 struct btrfsic_dev_state_hashtable *h);
 301 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void);
 302 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf);
 303 static int btrfsic_process_superblock(struct btrfsic_state *state,
 304                                       struct btrfs_fs_devices *fs_devices);
 305 static int btrfsic_process_metablock(struct btrfsic_state *state,
 306                                      struct btrfsic_block *block,
 307                                      struct btrfsic_block_data_ctx *block_ctx,
 308                                      int limit_nesting, int force_iodone_flag);
 309 static void btrfsic_read_from_block_data(
 310         struct btrfsic_block_data_ctx *block_ctx,
 311         void *dst, u32 offset, size_t len);
 312 static int btrfsic_create_link_to_next_block(
 313                 struct btrfsic_state *state,
 314                 struct btrfsic_block *block,
 315                 struct btrfsic_block_data_ctx
 316                 *block_ctx, u64 next_bytenr,
 317                 int limit_nesting,
 318                 struct btrfsic_block_data_ctx *next_block_ctx,
 319                 struct btrfsic_block **next_blockp,
 320                 int force_iodone_flag,
 321                 int *num_copiesp, int *mirror_nump,
 322                 struct btrfs_disk_key *disk_key,
 323                 u64 parent_generation);
 324 static int btrfsic_handle_extent_data(struct btrfsic_state *state,
 325                                       struct btrfsic_block *block,
 326                                       struct btrfsic_block_data_ctx *block_ctx,
 327                                       u32 item_offset, int force_iodone_flag);
 328 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
 329                              struct btrfsic_block_data_ctx *block_ctx_out,
 330                              int mirror_num);
 331 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx);
 332 static int btrfsic_read_block(struct btrfsic_state *state,
 333                               struct btrfsic_block_data_ctx *block_ctx);
 334 static void btrfsic_dump_database(struct btrfsic_state *state);
 335 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
 336                                      char **datav, unsigned int num_pages);
 337 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
 338                                           u64 dev_bytenr, char **mapped_datav,
 339                                           unsigned int num_pages,
 340                                           struct bio *bio, int *bio_is_patched,
 341                                           struct buffer_head *bh,
 342                                           int submit_bio_bh_rw);
 343 static int btrfsic_process_written_superblock(
 344                 struct btrfsic_state *state,
 345                 struct btrfsic_block *const block,
 346                 struct btrfs_super_block *const super_hdr);
 347 static void btrfsic_bio_end_io(struct bio *bp);
 348 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate);
 349 static int btrfsic_is_block_ref_by_superblock(const struct btrfsic_state *state,
 350                                               const struct btrfsic_block *block,
 351                                               int recursion_level);
 352 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
 353                                         struct btrfsic_block *const block,
 354                                         int recursion_level);
 355 static void btrfsic_print_add_link(const struct btrfsic_state *state,
 356                                    const struct btrfsic_block_link *l);
 357 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
 358                                    const struct btrfsic_block_link *l);
 359 static char btrfsic_get_block_type(const struct btrfsic_state *state,
 360                                    const struct btrfsic_block *block);
 361 static void btrfsic_dump_tree(const struct btrfsic_state *state);
 362 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
 363                                   const struct btrfsic_block *block,
 364                                   int indent_level);
 365 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
 366                 struct btrfsic_state *state,
 367                 struct btrfsic_block_data_ctx *next_block_ctx,
 368                 struct btrfsic_block *next_block,
 369                 struct btrfsic_block *from_block,
 370                 u64 parent_generation);
 371 static struct btrfsic_block *btrfsic_block_lookup_or_add(
 372                 struct btrfsic_state *state,
 373                 struct btrfsic_block_data_ctx *block_ctx,
 374                 const char *additional_string,
 375                 int is_metadata,
 376                 int is_iodone,
 377                 int never_written,
 378                 int mirror_num,
 379                 int *was_created);
 380 static int btrfsic_process_superblock_dev_mirror(
 381                 struct btrfsic_state *state,
 382                 struct btrfsic_dev_state *dev_state,
 383                 struct btrfs_device *device,
 384                 int superblock_mirror_num,
 385                 struct btrfsic_dev_state **selected_dev_state,
 386                 struct btrfs_super_block *selected_super);
 387 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(dev_t dev);
 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 btrfsic_block *b;
 535
 536         list_for_each_entry(b, h->table + hashval, collision_resolving_node) {
 537                 if (b->dev_state->bdev == bdev && b->dev_bytenr == dev_bytenr)
 538                         return b;
 539         }
 540
 541         return NULL;
 542 }
 543
 544 static void btrfsic_block_link_hashtable_init(
 545                 struct btrfsic_block_link_hashtable *h)
 546 {
 547         int i;
 548
 549         for (i = 0; i < BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE; i++)
 550                 INIT_LIST_HEAD(h->table + i);
 551 }
 552
 553 static void btrfsic_block_link_hashtable_add(
 554                 struct btrfsic_block_link *l,
 555                 struct btrfsic_block_link_hashtable *h)
 556 {
 557         const unsigned int hashval =
 558             (((unsigned int)(l->block_ref_to->dev_bytenr >> 16)) ^
 559              ((unsigned int)(l->block_ref_from->dev_bytenr >> 16)) ^
 560              ((unsigned int)((uintptr_t)l->block_ref_to->dev_state->bdev)) ^
 561              ((unsigned int)((uintptr_t)l->block_ref_from->dev_state->bdev)))
 562              & (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
 563
 564         BUG_ON(NULL == l->block_ref_to);
 565         BUG_ON(NULL == l->block_ref_from);
 566         list_add(&l->collision_resolving_node, h->table + hashval);
 567 }
 568
 569 static void btrfsic_block_link_hashtable_remove(struct btrfsic_block_link *l)
 570 {
 571         list_del(&l->collision_resolving_node);
 572 }
 573
 574 static struct btrfsic_block_link *btrfsic_block_link_hashtable_lookup(
 575                 struct block_device *bdev_ref_to,
 576                 u64 dev_bytenr_ref_to,
 577                 struct block_device *bdev_ref_from,
 578                 u64 dev_bytenr_ref_from,
 579                 struct btrfsic_block_link_hashtable *h)
 580 {
 581         const unsigned int hashval =
 582             (((unsigned int)(dev_bytenr_ref_to >> 16)) ^
 583              ((unsigned int)(dev_bytenr_ref_from >> 16)) ^
 584              ((unsigned int)((uintptr_t)bdev_ref_to)) ^
 585              ((unsigned int)((uintptr_t)bdev_ref_from))) &
 586              (BTRFSIC_BLOCK_LINK_HASHTABLE_SIZE - 1);
 587         struct btrfsic_block_link *l;
 588
 589         list_for_each_entry(l, h->table + hashval, collision_resolving_node) {
 590                 BUG_ON(NULL == l->block_ref_to);
 591                 BUG_ON(NULL == l->block_ref_from);
 592                 if (l->block_ref_to->dev_state->bdev == bdev_ref_to &&
 593                     l->block_ref_to->dev_bytenr == dev_bytenr_ref_to &&
 594                     l->block_ref_from->dev_state->bdev == bdev_ref_from &&
 595                     l->block_ref_from->dev_bytenr == dev_bytenr_ref_from)
 596                         return l;
 597         }
 598
 599         return NULL;
 600 }
 601
 602 static void btrfsic_dev_state_hashtable_init(
 603                 struct btrfsic_dev_state_hashtable *h)
 604 {
 605         int i;
 606
 607         for (i = 0; i < BTRFSIC_DEV2STATE_HASHTABLE_SIZE; i++)
 608                 INIT_LIST_HEAD(h->table + i);
 609 }
 610
 611 static void btrfsic_dev_state_hashtable_add(
 612                 struct btrfsic_dev_state *ds,
 613                 struct btrfsic_dev_state_hashtable *h)
 614 {
 615         const unsigned int hashval =
 616             (((unsigned int)((uintptr_t)ds->bdev)) &
 617              (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1));
 618
 619         list_add(&ds->collision_resolving_node, h->table + hashval);
 620 }
 621
 622 static void btrfsic_dev_state_hashtable_remove(struct btrfsic_dev_state *ds)
 623 {
 624         list_del(&ds->collision_resolving_node);
 625 }
 626
 627 static struct btrfsic_dev_state *btrfsic_dev_state_hashtable_lookup(dev_t dev,
 628                 struct btrfsic_dev_state_hashtable *h)
 629 {
 630         const unsigned int hashval =
 631                 dev & (BTRFSIC_DEV2STATE_HASHTABLE_SIZE - 1);
 632         struct btrfsic_dev_state *ds;
 633
 634         list_for_each_entry(ds, h->table + hashval, collision_resolving_node) {
 635                 if (ds->bdev->bd_dev == dev)
 636                         return ds;
 637         }
 638
 639         return NULL;
 640 }
 641
 642 static int btrfsic_process_superblock(struct btrfsic_state *state,
 643                                       struct btrfs_fs_devices *fs_devices)
 644 {
 645         struct btrfs_super_block *selected_super;
 646         struct list_head *dev_head = &fs_devices->devices;
 647         struct btrfs_device *device;
 648         struct btrfsic_dev_state *selected_dev_state = NULL;
 649         int ret = 0;
 650         int pass;
 651
 652         BUG_ON(NULL == state);
 653         selected_super = kzalloc(sizeof(*selected_super), GFP_NOFS);
 654         if (NULL == selected_super) {
 655                 pr_info("btrfsic: error, kmalloc failed!\n");
 656                 return -ENOMEM;
 657         }
 658
 659         list_for_each_entry(device, dev_head, dev_list) {
 660                 int i;
 661                 struct btrfsic_dev_state *dev_state;
 662
 663                 if (!device->bdev || !device->name)
 664                         continue;
 665
 666                 dev_state = btrfsic_dev_state_lookup(device->bdev->bd_dev);
 667                 BUG_ON(NULL == dev_state);
 668                 for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 669                         ret = btrfsic_process_superblock_dev_mirror(
 670                                         state, dev_state, device, i,
 671                                         &selected_dev_state, selected_super);
 672                         if (0 != ret && 0 == i) {
 673                                 kfree(selected_super);
 674                                 return ret;
 675                         }
 676                 }
 677         }
 678
 679         if (NULL == state->latest_superblock) {
 680                 pr_info("btrfsic: no superblock found!\n");
 681                 kfree(selected_super);
 682                 return -1;
 683         }
 684
 685         state->csum_size = btrfs_super_csum_size(selected_super);
 686
 687         for (pass = 0; pass < 3; pass++) {
 688                 int num_copies;
 689                 int mirror_num;
 690                 u64 next_bytenr;
 691
 692                 switch (pass) {
 693                 case 0:
 694                         next_bytenr = btrfs_super_root(selected_super);
 695                         if (state->print_mask &
 696                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 697                                 pr_info("root@%llu\n", next_bytenr);
 698                         break;
 699                 case 1:
 700                         next_bytenr = btrfs_super_chunk_root(selected_super);
 701                         if (state->print_mask &
 702                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 703                                 pr_info("chunk@%llu\n", next_bytenr);
 704                         break;
 705                 case 2:
 706                         next_bytenr = btrfs_super_log_root(selected_super);
 707                         if (0 == next_bytenr)
 708                                 continue;
 709                         if (state->print_mask &
 710                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
 711                                 pr_info("log@%llu\n", next_bytenr);
 712                         break;
 713                 }
 714
 715                 num_copies = btrfs_num_copies(state->fs_info, next_bytenr,
 716                                               state->metablock_size);
 717                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 718                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
 719                                next_bytenr, num_copies);
 720
 721                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 722                         struct btrfsic_block *next_block;
 723                         struct btrfsic_block_data_ctx tmp_next_block_ctx;
 724                         struct btrfsic_block_link *l;
 725
 726                         ret = btrfsic_map_block(state, next_bytenr,
 727                                                 state->metablock_size,
 728                                                 &tmp_next_block_ctx,
 729                                                 mirror_num);
 730                         if (ret) {
 731                                 pr_info("btrfsic: btrfsic_map_block(root @%llu, mirror %d) failed!\n",
 732                                        next_bytenr, mirror_num);
 733                                 kfree(selected_super);
 734                                 return -1;
 735                         }
 736
 737                         next_block = btrfsic_block_hashtable_lookup(
 738                                         tmp_next_block_ctx.dev->bdev,
 739                                         tmp_next_block_ctx.dev_bytenr,
 740                                         &state->block_hashtable);
 741                         BUG_ON(NULL == next_block);
 742
 743                         l = btrfsic_block_link_hashtable_lookup(
 744                                         tmp_next_block_ctx.dev->bdev,
 745                                         tmp_next_block_ctx.dev_bytenr,
 746                                         state->latest_superblock->dev_state->
 747                                         bdev,
 748                                         state->latest_superblock->dev_bytenr,
 749                                         &state->block_link_hashtable);
 750                         BUG_ON(NULL == l);
 751
 752                         ret = btrfsic_read_block(state, &tmp_next_block_ctx);
 753                         if (ret < (int)PAGE_SIZE) {
 754                                 pr_info("btrfsic: read @logical %llu failed!\n",
 755                                        tmp_next_block_ctx.start);
 756                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
 757                                 kfree(selected_super);
 758                                 return -1;
 759                         }
 760
 761                         ret = btrfsic_process_metablock(state,
 762                                                         next_block,
 763                                                         &tmp_next_block_ctx,
 764                                                         BTRFS_MAX_LEVEL + 3, 1);
 765                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
 766                 }
 767         }
 768
 769         kfree(selected_super);
 770         return ret;
 771 }
 772
 773 static int btrfsic_process_superblock_dev_mirror(
 774                 struct btrfsic_state *state,
 775                 struct btrfsic_dev_state *dev_state,
 776                 struct btrfs_device *device,
 777                 int superblock_mirror_num,
 778                 struct btrfsic_dev_state **selected_dev_state,
 779                 struct btrfs_super_block *selected_super)
 780 {
 781         struct btrfs_fs_info *fs_info = state->fs_info;
 782         struct btrfs_super_block *super_tmp;
 783         u64 dev_bytenr;
 784         struct buffer_head *bh;
 785         struct btrfsic_block *superblock_tmp;
 786         int pass;
 787         struct block_device *const superblock_bdev = device->bdev;
 788
 789         /* super block bytenr is always the unmapped device bytenr */
 790         dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
 791         if (dev_bytenr + BTRFS_SUPER_INFO_SIZE > device->commit_total_bytes)
 792                 return -1;
 793         bh = __bread(superblock_bdev, dev_bytenr / BTRFS_BDEV_BLOCKSIZE,
 794                      BTRFS_SUPER_INFO_SIZE);
 795         if (NULL == bh)
 796                 return -1;
 797         super_tmp = (struct btrfs_super_block *)
 798             (bh->b_data + (dev_bytenr & (BTRFS_BDEV_BLOCKSIZE - 1)));
 799
 800         if (btrfs_super_bytenr(super_tmp) != dev_bytenr ||
 801             btrfs_super_magic(super_tmp) != BTRFS_MAGIC ||
 802             memcmp(device->uuid, super_tmp->dev_item.uuid, BTRFS_UUID_SIZE) ||
 803             btrfs_super_nodesize(super_tmp) != state->metablock_size ||
 804             btrfs_super_sectorsize(super_tmp) != state->datablock_size) {
 805                 brelse(bh);
 806                 return 0;
 807         }
 808
 809         superblock_tmp =
 810             btrfsic_block_hashtable_lookup(superblock_bdev,
 811                                            dev_bytenr,
 812                                            &state->block_hashtable);
 813         if (NULL == superblock_tmp) {
 814                 superblock_tmp = btrfsic_block_alloc();
 815                 if (NULL == superblock_tmp) {
 816                         pr_info("btrfsic: error, kmalloc failed!\n");
 817                         brelse(bh);
 818                         return -1;
 819                 }
 820                 /* for superblock, only the dev_bytenr makes sense */
 821                 superblock_tmp->dev_bytenr = dev_bytenr;
 822                 superblock_tmp->dev_state = dev_state;
 823                 superblock_tmp->logical_bytenr = dev_bytenr;
 824                 superblock_tmp->generation = btrfs_super_generation(super_tmp);
 825                 superblock_tmp->is_metadata = 1;
 826                 superblock_tmp->is_superblock = 1;
 827                 superblock_tmp->is_iodone = 1;
 828                 superblock_tmp->never_written = 0;
 829                 superblock_tmp->mirror_num = 1 + superblock_mirror_num;
 830                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
 831                         btrfs_info_in_rcu(fs_info,
 832                                 "new initial S-block (bdev %p, %s) @%llu (%s/%llu/%d)",
 833                                      superblock_bdev,
 834                                      rcu_str_deref(device->name), dev_bytenr,
 835                                      dev_state->name, dev_bytenr,
 836                                      superblock_mirror_num);
 837                 list_add(&superblock_tmp->all_blocks_node,
 838                          &state->all_blocks_list);
 839                 btrfsic_block_hashtable_add(superblock_tmp,
 840                                             &state->block_hashtable);
 841         }
 842
 843         /* select the one with the highest generation field */
 844         if (btrfs_super_generation(super_tmp) >
 845             state->max_superblock_generation ||
 846             0 == state->max_superblock_generation) {
 847                 memcpy(selected_super, super_tmp, sizeof(*selected_super));
 848                 *selected_dev_state = dev_state;
 849                 state->max_superblock_generation =
 850                     btrfs_super_generation(super_tmp);
 851                 state->latest_superblock = superblock_tmp;
 852         }
 853
 854         for (pass = 0; pass < 3; pass++) {
 855                 u64 next_bytenr;
 856                 int num_copies;
 857                 int mirror_num;
 858                 const char *additional_string = NULL;
 859                 struct btrfs_disk_key tmp_disk_key;
 860
 861                 tmp_disk_key.type = BTRFS_ROOT_ITEM_KEY;
 862                 tmp_disk_key.offset = 0;
 863                 switch (pass) {
 864                 case 0:
 865                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 866                                                     BTRFS_ROOT_TREE_OBJECTID);
 867                         additional_string = "initial root ";
 868                         next_bytenr = btrfs_super_root(super_tmp);
 869                         break;
 870                 case 1:
 871                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 872                                                     BTRFS_CHUNK_TREE_OBJECTID);
 873                         additional_string = "initial chunk ";
 874                         next_bytenr = btrfs_super_chunk_root(super_tmp);
 875                         break;
 876                 case 2:
 877                         btrfs_set_disk_key_objectid(&tmp_disk_key,
 878                                                     BTRFS_TREE_LOG_OBJECTID);
 879                         additional_string = "initial log ";
 880                         next_bytenr = btrfs_super_log_root(super_tmp);
 881                         if (0 == next_bytenr)
 882                                 continue;
 883                         break;
 884                 }
 885
 886                 num_copies = btrfs_num_copies(fs_info, next_bytenr,
 887                                               state->metablock_size);
 888                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
 889                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
 890                                next_bytenr, num_copies);
 891                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
 892                         struct btrfsic_block *next_block;
 893                         struct btrfsic_block_data_ctx tmp_next_block_ctx;
 894                         struct btrfsic_block_link *l;
 895
 896                         if (btrfsic_map_block(state, next_bytenr,
 897                                               state->metablock_size,
 898                                               &tmp_next_block_ctx,
 899                                               mirror_num)) {
 900                                 pr_info("btrfsic: btrfsic_map_block(bytenr @%llu, mirror %d) failed!\n",
 901                                        next_bytenr, mirror_num);
 902                                 brelse(bh);
 903                                 return -1;
 904                         }
 905
 906                         next_block = btrfsic_block_lookup_or_add(
 907                                         state, &tmp_next_block_ctx,
 908                                         additional_string, 1, 1, 0,
 909                                         mirror_num, NULL);
 910                         if (NULL == next_block) {
 911                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
 912                                 brelse(bh);
 913                                 return -1;
 914                         }
 915
 916                         next_block->disk_key = tmp_disk_key;
 917                         next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
 918                         l = btrfsic_block_link_lookup_or_add(
 919                                         state, &tmp_next_block_ctx,
 920                                         next_block, superblock_tmp,
 921                                         BTRFSIC_GENERATION_UNKNOWN);
 922                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
 923                         if (NULL == l) {
 924                                 brelse(bh);
 925                                 return -1;
 926                         }
 927                 }
 928         }
 929         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_ALL_TREES)
 930                 btrfsic_dump_tree_sub(state, superblock_tmp, 0);
 931
 932         brelse(bh);
 933         return 0;
 934 }
 935
 936 static struct btrfsic_stack_frame *btrfsic_stack_frame_alloc(void)
 937 {
 938         struct btrfsic_stack_frame *sf;
 939
 940         sf = kzalloc(sizeof(*sf), GFP_NOFS);
 941         if (NULL == sf)
 942                 pr_info("btrfsic: alloc memory failed!\n");
 943         else
 944                 sf->magic = BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER;
 945         return sf;
 946 }
 947
 948 static void btrfsic_stack_frame_free(struct btrfsic_stack_frame *sf)
 949 {
 950         BUG_ON(!(NULL == sf ||
 951                  BTRFSIC_BLOCK_STACK_FRAME_MAGIC_NUMBER == sf->magic));
 952         kfree(sf);
 953 }
 954
 955 static int btrfsic_process_metablock(
 956                 struct btrfsic_state *state,
 957                 struct btrfsic_block *const first_block,
 958                 struct btrfsic_block_data_ctx *const first_block_ctx,
 959                 int first_limit_nesting, int force_iodone_flag)
 960 {
 961         struct btrfsic_stack_frame initial_stack_frame = { 0 };
 962         struct btrfsic_stack_frame *sf;
 963         struct btrfsic_stack_frame *next_stack;
 964         struct btrfs_header *const first_hdr =
 965                 (struct btrfs_header *)first_block_ctx->datav[0];
 966
 967         BUG_ON(!first_hdr);
 968         sf = &initial_stack_frame;
 969         sf->error = 0;
 970         sf->i = -1;
 971         sf->limit_nesting = first_limit_nesting;
 972         sf->block = first_block;
 973         sf->block_ctx = first_block_ctx;
 974         sf->next_block = NULL;
 975         sf->hdr = first_hdr;
 976         sf->prev = NULL;
 977
 978 continue_with_new_stack_frame:
 979         sf->block->generation = le64_to_cpu(sf->hdr->generation);
 980         if (0 == sf->hdr->level) {
 981                 struct btrfs_leaf *const leafhdr =
 982                     (struct btrfs_leaf *)sf->hdr;
 983
 984                 if (-1 == sf->i) {
 985                         sf->nr = btrfs_stack_header_nritems(&leafhdr->header);
 986
 987                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
 988                                 pr_info("leaf %llu items %d generation %llu owner %llu\n",
 989                                        sf->block_ctx->start, sf->nr,
 990                                        btrfs_stack_header_generation(
 991                                                &leafhdr->header),
 992                                        btrfs_stack_header_owner(
 993                                                &leafhdr->header));
 994                 }
 995
 996 continue_with_current_leaf_stack_frame:
 997                 if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
 998                         sf->i++;
 999                         sf->num_copies = 0;
1000                 }
1001
1002                 if (sf->i < sf->nr) {
1003                         struct btrfs_item disk_item;
1004                         u32 disk_item_offset =
1005                                 (uintptr_t)(leafhdr->items + sf->i) -
1006                                 (uintptr_t)leafhdr;
1007                         struct btrfs_disk_key *disk_key;
1008                         u8 type;
1009                         u32 item_offset;
1010                         u32 item_size;
1011
1012                         if (disk_item_offset + sizeof(struct btrfs_item) >
1013                             sf->block_ctx->len) {
1014 leaf_item_out_of_bounce_error:
1015                                 pr_info("btrfsic: leaf item out of bounce at logical %llu, dev %s\n",
1016                                        sf->block_ctx->start,
1017                                        sf->block_ctx->dev->name);
1018                                 goto one_stack_frame_backwards;
1019                         }
1020                         btrfsic_read_from_block_data(sf->block_ctx,
1021                                                      &disk_item,
1022                                                      disk_item_offset,
1023                                                      sizeof(struct btrfs_item));
1024                         item_offset = btrfs_stack_item_offset(&disk_item);
1025                         item_size = btrfs_stack_item_size(&disk_item);
1026                         disk_key = &disk_item.key;
1027                         type = btrfs_disk_key_type(disk_key);
1028
1029                         if (BTRFS_ROOT_ITEM_KEY == type) {
1030                                 struct btrfs_root_item root_item;
1031                                 u32 root_item_offset;
1032                                 u64 next_bytenr;
1033
1034                                 root_item_offset = item_offset +
1035                                         offsetof(struct btrfs_leaf, items);
1036                                 if (root_item_offset + item_size >
1037                                     sf->block_ctx->len)
1038                                         goto leaf_item_out_of_bounce_error;
1039                                 btrfsic_read_from_block_data(
1040                                         sf->block_ctx, &root_item,
1041                                         root_item_offset,
1042                                         item_size);
1043                                 next_bytenr = btrfs_root_bytenr(&root_item);
1044
1045                                 sf->error =
1046                                     btrfsic_create_link_to_next_block(
1047                                                 state,
1048                                                 sf->block,
1049                                                 sf->block_ctx,
1050                                                 next_bytenr,
1051                                                 sf->limit_nesting,
1052                                                 &sf->next_block_ctx,
1053                                                 &sf->next_block,
1054                                                 force_iodone_flag,
1055                                                 &sf->num_copies,
1056                                                 &sf->mirror_num,
1057                                                 disk_key,
1058                                                 btrfs_root_generation(
1059                                                 &root_item));
1060                                 if (sf->error)
1061                                         goto one_stack_frame_backwards;
1062
1063                                 if (NULL != sf->next_block) {
1064                                         struct btrfs_header *const next_hdr =
1065                                             (struct btrfs_header *)
1066                                             sf->next_block_ctx.datav[0];
1067
1068                                         next_stack =
1069                                             btrfsic_stack_frame_alloc();
1070                                         if (NULL == next_stack) {
1071                                                 sf->error = -1;
1072                                                 btrfsic_release_block_ctx(
1073                                                                 &sf->
1074                                                                 next_block_ctx);
1075                                                 goto one_stack_frame_backwards;
1076                                         }
1077
1078                                         next_stack->i = -1;
1079                                         next_stack->block = sf->next_block;
1080                                         next_stack->block_ctx =
1081                                             &sf->next_block_ctx;
1082                                         next_stack->next_block = NULL;
1083                                         next_stack->hdr = next_hdr;
1084                                         next_stack->limit_nesting =
1085                                             sf->limit_nesting - 1;
1086                                         next_stack->prev = sf;
1087                                         sf = next_stack;
1088                                         goto continue_with_new_stack_frame;
1089                                 }
1090                         } else if (BTRFS_EXTENT_DATA_KEY == type &&
1091                                    state->include_extent_data) {
1092                                 sf->error = btrfsic_handle_extent_data(
1093                                                 state,
1094                                                 sf->block,
1095                                                 sf->block_ctx,
1096                                                 item_offset,
1097                                                 force_iodone_flag);
1098                                 if (sf->error)
1099                                         goto one_stack_frame_backwards;
1100                         }
1101
1102                         goto continue_with_current_leaf_stack_frame;
1103                 }
1104         } else {
1105                 struct btrfs_node *const nodehdr = (struct btrfs_node *)sf->hdr;
1106
1107                 if (-1 == sf->i) {
1108                         sf->nr = btrfs_stack_header_nritems(&nodehdr->header);
1109
1110                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1111                                 pr_info("node %llu level %d items %d generation %llu owner %llu\n",
1112                                        sf->block_ctx->start,
1113                                        nodehdr->header.level, sf->nr,
1114                                        btrfs_stack_header_generation(
1115                                        &nodehdr->header),
1116                                        btrfs_stack_header_owner(
1117                                        &nodehdr->header));
1118                 }
1119
1120 continue_with_current_node_stack_frame:
1121                 if (0 == sf->num_copies || sf->mirror_num > sf->num_copies) {
1122                         sf->i++;
1123                         sf->num_copies = 0;
1124                 }
1125
1126                 if (sf->i < sf->nr) {
1127                         struct btrfs_key_ptr key_ptr;
1128                         u32 key_ptr_offset;
1129                         u64 next_bytenr;
1130
1131                         key_ptr_offset = (uintptr_t)(nodehdr->ptrs + sf->i) -
1132                                           (uintptr_t)nodehdr;
1133                         if (key_ptr_offset + sizeof(struct btrfs_key_ptr) >
1134                             sf->block_ctx->len) {
1135                                 pr_info("btrfsic: node item out of bounce at logical %llu, dev %s\n",
1136                                        sf->block_ctx->start,
1137                                        sf->block_ctx->dev->name);
1138                                 goto one_stack_frame_backwards;
1139                         }
1140                         btrfsic_read_from_block_data(
1141                                 sf->block_ctx, &key_ptr, key_ptr_offset,
1142                                 sizeof(struct btrfs_key_ptr));
1143                         next_bytenr = btrfs_stack_key_blockptr(&key_ptr);
1144
1145                         sf->error = btrfsic_create_link_to_next_block(
1146                                         state,
1147                                         sf->block,
1148                                         sf->block_ctx,
1149                                         next_bytenr,
1150                                         sf->limit_nesting,
1151                                         &sf->next_block_ctx,
1152                                         &sf->next_block,
1153                                         force_iodone_flag,
1154                                         &sf->num_copies,
1155                                         &sf->mirror_num,
1156                                         &key_ptr.key,
1157                                         btrfs_stack_key_generation(&key_ptr));
1158                         if (sf->error)
1159                                 goto one_stack_frame_backwards;
1160
1161                         if (NULL != sf->next_block) {
1162                                 struct btrfs_header *const next_hdr =
1163                                     (struct btrfs_header *)
1164                                     sf->next_block_ctx.datav[0];
1165
1166                                 next_stack = btrfsic_stack_frame_alloc();
1167                                 if (NULL == next_stack) {
1168                                         sf->error = -1;
1169                                         goto one_stack_frame_backwards;
1170                                 }
1171
1172                                 next_stack->i = -1;
1173                                 next_stack->block = sf->next_block;
1174                                 next_stack->block_ctx = &sf->next_block_ctx;
1175                                 next_stack->next_block = NULL;
1176                                 next_stack->hdr = next_hdr;
1177                                 next_stack->limit_nesting =
1178                                     sf->limit_nesting - 1;
1179                                 next_stack->prev = sf;
1180                                 sf = next_stack;
1181                                 goto continue_with_new_stack_frame;
1182                         }
1183
1184                         goto continue_with_current_node_stack_frame;
1185                 }
1186         }
1187
1188 one_stack_frame_backwards:
1189         if (NULL != sf->prev) {
1190                 struct btrfsic_stack_frame *const prev = sf->prev;
1191
1192                 /* the one for the initial block is freed in the caller */
1193                 btrfsic_release_block_ctx(sf->block_ctx);
1194
1195                 if (sf->error) {
1196                         prev->error = sf->error;
1197                         btrfsic_stack_frame_free(sf);
1198                         sf = prev;
1199                         goto one_stack_frame_backwards;
1200                 }
1201
1202                 btrfsic_stack_frame_free(sf);
1203                 sf = prev;
1204                 goto continue_with_new_stack_frame;
1205         } else {
1206                 BUG_ON(&initial_stack_frame != sf);
1207         }
1208
1209         return sf->error;
1210 }
1211
1212 static void btrfsic_read_from_block_data(
1213         struct btrfsic_block_data_ctx *block_ctx,
1214         void *dstv, u32 offset, size_t len)
1215 {
1216         size_t cur;
1217         size_t offset_in_page;
1218         char *kaddr;
1219         char *dst = (char *)dstv;
1220         size_t start_offset = block_ctx->start & ((u64)PAGE_SIZE - 1);
1221         unsigned long i = (start_offset + offset) >> PAGE_SHIFT;
1222
1223         WARN_ON(offset + len > block_ctx->len);
1224         offset_in_page = (start_offset + offset) & (PAGE_SIZE - 1);
1225
1226         while (len > 0) {
1227                 cur = min(len, ((size_t)PAGE_SIZE - offset_in_page));
1228                 BUG_ON(i >= DIV_ROUND_UP(block_ctx->len, PAGE_SIZE));
1229                 kaddr = block_ctx->datav[i];
1230                 memcpy(dst, kaddr + offset_in_page, cur);
1231
1232                 dst += cur;
1233                 len -= cur;
1234                 offset_in_page = 0;
1235                 i++;
1236         }
1237 }
1238
1239 static int btrfsic_create_link_to_next_block(
1240                 struct btrfsic_state *state,
1241                 struct btrfsic_block *block,
1242                 struct btrfsic_block_data_ctx *block_ctx,
1243                 u64 next_bytenr,
1244                 int limit_nesting,
1245                 struct btrfsic_block_data_ctx *next_block_ctx,
1246                 struct btrfsic_block **next_blockp,
1247                 int force_iodone_flag,
1248                 int *num_copiesp, int *mirror_nump,
1249                 struct btrfs_disk_key *disk_key,
1250                 u64 parent_generation)
1251 {
1252         struct btrfs_fs_info *fs_info = state->fs_info;
1253         struct btrfsic_block *next_block = NULL;
1254         int ret;
1255         struct btrfsic_block_link *l;
1256         int did_alloc_block_link;
1257         int block_was_created;
1258
1259         *next_blockp = NULL;
1260         if (0 == *num_copiesp) {
1261                 *num_copiesp = btrfs_num_copies(fs_info, next_bytenr,
1262                                                 state->metablock_size);
1263                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1264                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
1265                                next_bytenr, *num_copiesp);
1266                 *mirror_nump = 1;
1267         }
1268
1269         if (*mirror_nump > *num_copiesp)
1270                 return 0;
1271
1272         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1273                 pr_info("btrfsic_create_link_to_next_block(mirror_num=%d)\n",
1274                        *mirror_nump);
1275         ret = btrfsic_map_block(state, next_bytenr,
1276                                 state->metablock_size,
1277                                 next_block_ctx, *mirror_nump);
1278         if (ret) {
1279                 pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1280                        next_bytenr, *mirror_nump);
1281                 btrfsic_release_block_ctx(next_block_ctx);
1282                 *next_blockp = NULL;
1283                 return -1;
1284         }
1285
1286         next_block = btrfsic_block_lookup_or_add(state,
1287                                                  next_block_ctx, "referenced ",
1288                                                  1, force_iodone_flag,
1289                                                  !force_iodone_flag,
1290                                                  *mirror_nump,
1291                                                  &block_was_created);
1292         if (NULL == next_block) {
1293                 btrfsic_release_block_ctx(next_block_ctx);
1294                 *next_blockp = NULL;
1295                 return -1;
1296         }
1297         if (block_was_created) {
1298                 l = NULL;
1299                 next_block->generation = BTRFSIC_GENERATION_UNKNOWN;
1300         } else {
1301                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE) {
1302                         if (next_block->logical_bytenr != next_bytenr &&
1303                             !(!next_block->is_metadata &&
1304                               0 == next_block->logical_bytenr))
1305                                 pr_info("Referenced block @%llu (%s/%llu/%d) found in hash table, %c, bytenr mismatch (!= stored %llu).\n",
1306                                        next_bytenr, next_block_ctx->dev->name,
1307                                        next_block_ctx->dev_bytenr, *mirror_nump,
1308                                        btrfsic_get_block_type(state,
1309                                                               next_block),
1310                                        next_block->logical_bytenr);
1311                         else
1312                                 pr_info("Referenced block @%llu (%s/%llu/%d) found in hash table, %c.\n",
1313                                        next_bytenr, next_block_ctx->dev->name,
1314                                        next_block_ctx->dev_bytenr, *mirror_nump,
1315                                        btrfsic_get_block_type(state,
1316                                                               next_block));
1317                 }
1318                 next_block->logical_bytenr = next_bytenr;
1319
1320                 next_block->mirror_num = *mirror_nump;
1321                 l = btrfsic_block_link_hashtable_lookup(
1322                                 next_block_ctx->dev->bdev,
1323                                 next_block_ctx->dev_bytenr,
1324                                 block_ctx->dev->bdev,
1325                                 block_ctx->dev_bytenr,
1326                                 &state->block_link_hashtable);
1327         }
1328
1329         next_block->disk_key = *disk_key;
1330         if (NULL == l) {
1331                 l = btrfsic_block_link_alloc();
1332                 if (NULL == l) {
1333                         pr_info("btrfsic: error, kmalloc failed!\n");
1334                         btrfsic_release_block_ctx(next_block_ctx);
1335                         *next_blockp = NULL;
1336                         return -1;
1337                 }
1338
1339                 did_alloc_block_link = 1;
1340                 l->block_ref_to = next_block;
1341                 l->block_ref_from = block;
1342                 l->ref_cnt = 1;
1343                 l->parent_generation = parent_generation;
1344
1345                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1346                         btrfsic_print_add_link(state, l);
1347
1348                 list_add(&l->node_ref_to, &block->ref_to_list);
1349                 list_add(&l->node_ref_from, &next_block->ref_from_list);
1350
1351                 btrfsic_block_link_hashtable_add(l,
1352                                                  &state->block_link_hashtable);
1353         } else {
1354                 did_alloc_block_link = 0;
1355                 if (0 == limit_nesting) {
1356                         l->ref_cnt++;
1357                         l->parent_generation = parent_generation;
1358                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1359                                 btrfsic_print_add_link(state, l);
1360                 }
1361         }
1362
1363         if (limit_nesting > 0 && did_alloc_block_link) {
1364                 ret = btrfsic_read_block(state, next_block_ctx);
1365                 if (ret < (int)next_block_ctx->len) {
1366                         pr_info("btrfsic: read block @logical %llu failed!\n",
1367                                next_bytenr);
1368                         btrfsic_release_block_ctx(next_block_ctx);
1369                         *next_blockp = NULL;
1370                         return -1;
1371                 }
1372
1373                 *next_blockp = next_block;
1374         } else {
1375                 *next_blockp = NULL;
1376         }
1377         (*mirror_nump)++;
1378
1379         return 0;
1380 }
1381
1382 static int btrfsic_handle_extent_data(
1383                 struct btrfsic_state *state,
1384                 struct btrfsic_block *block,
1385                 struct btrfsic_block_data_ctx *block_ctx,
1386                 u32 item_offset, int force_iodone_flag)
1387 {
1388         struct btrfs_fs_info *fs_info = state->fs_info;
1389         struct btrfs_file_extent_item file_extent_item;
1390         u64 file_extent_item_offset;
1391         u64 next_bytenr;
1392         u64 num_bytes;
1393         u64 generation;
1394         struct btrfsic_block_link *l;
1395         int ret;
1396
1397         file_extent_item_offset = offsetof(struct btrfs_leaf, items) +
1398                                   item_offset;
1399         if (file_extent_item_offset +
1400             offsetof(struct btrfs_file_extent_item, disk_num_bytes) >
1401             block_ctx->len) {
1402                 pr_info("btrfsic: file item out of bounce at logical %llu, dev %s\n",
1403                        block_ctx->start, block_ctx->dev->name);
1404                 return -1;
1405         }
1406
1407         btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1408                 file_extent_item_offset,
1409                 offsetof(struct btrfs_file_extent_item, disk_num_bytes));
1410         if (BTRFS_FILE_EXTENT_REG != file_extent_item.type ||
1411             btrfs_stack_file_extent_disk_bytenr(&file_extent_item) == 0) {
1412                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1413                         pr_info("extent_data: type %u, disk_bytenr = %llu\n",
1414                                file_extent_item.type,
1415                                btrfs_stack_file_extent_disk_bytenr(
1416                                &file_extent_item));
1417                 return 0;
1418         }
1419
1420         if (file_extent_item_offset + sizeof(struct btrfs_file_extent_item) >
1421             block_ctx->len) {
1422                 pr_info("btrfsic: file item out of bounce at logical %llu, dev %s\n",
1423                        block_ctx->start, block_ctx->dev->name);
1424                 return -1;
1425         }
1426         btrfsic_read_from_block_data(block_ctx, &file_extent_item,
1427                                      file_extent_item_offset,
1428                                      sizeof(struct btrfs_file_extent_item));
1429         next_bytenr = btrfs_stack_file_extent_disk_bytenr(&file_extent_item);
1430         if (btrfs_stack_file_extent_compression(&file_extent_item) ==
1431             BTRFS_COMPRESS_NONE) {
1432                 next_bytenr += btrfs_stack_file_extent_offset(&file_extent_item);
1433                 num_bytes = btrfs_stack_file_extent_num_bytes(&file_extent_item);
1434         } else {
1435                 num_bytes = btrfs_stack_file_extent_disk_num_bytes(&file_extent_item);
1436         }
1437         generation = btrfs_stack_file_extent_generation(&file_extent_item);
1438
1439         if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1440                 pr_info("extent_data: type %u, disk_bytenr = %llu, offset = %llu, num_bytes = %llu\n",
1441                        file_extent_item.type,
1442                        btrfs_stack_file_extent_disk_bytenr(&file_extent_item),
1443                        btrfs_stack_file_extent_offset(&file_extent_item),
1444                        num_bytes);
1445         while (num_bytes > 0) {
1446                 u32 chunk_len;
1447                 int num_copies;
1448                 int mirror_num;
1449
1450                 if (num_bytes > state->datablock_size)
1451                         chunk_len = state->datablock_size;
1452                 else
1453                         chunk_len = num_bytes;
1454
1455                 num_copies = btrfs_num_copies(fs_info, next_bytenr,
1456                                               state->datablock_size);
1457                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
1458                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
1459                                next_bytenr, num_copies);
1460                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
1461                         struct btrfsic_block_data_ctx next_block_ctx;
1462                         struct btrfsic_block *next_block;
1463                         int block_was_created;
1464
1465                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1466                                 pr_info("btrfsic_handle_extent_data(mirror_num=%d)\n",
1467                                         mirror_num);
1468                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERY_VERBOSE)
1469                                 pr_info("\tdisk_bytenr = %llu, num_bytes %u\n",
1470                                        next_bytenr, chunk_len);
1471                         ret = btrfsic_map_block(state, next_bytenr,
1472                                                 chunk_len, &next_block_ctx,
1473                                                 mirror_num);
1474                         if (ret) {
1475                                 pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
1476                                        next_bytenr, mirror_num);
1477                                 return -1;
1478                         }
1479
1480                         next_block = btrfsic_block_lookup_or_add(
1481                                         state,
1482                                         &next_block_ctx,
1483                                         "referenced ",
1484                                         0,
1485                                         force_iodone_flag,
1486                                         !force_iodone_flag,
1487                                         mirror_num,
1488                                         &block_was_created);
1489                         if (NULL == next_block) {
1490                                 pr_info("btrfsic: error, kmalloc failed!\n");
1491                                 btrfsic_release_block_ctx(&next_block_ctx);
1492                                 return -1;
1493                         }
1494                         if (!block_was_created) {
1495                                 if ((state->print_mask &
1496                                      BTRFSIC_PRINT_MASK_VERBOSE) &&
1497                                     next_block->logical_bytenr != next_bytenr &&
1498                                     !(!next_block->is_metadata &&
1499                                       0 == next_block->logical_bytenr)) {
1500                                         pr_info("Referenced block @%llu (%s/%llu/%d) found in hash table, D, bytenr mismatch (!= stored %llu).\n",
1501                                                next_bytenr,
1502                                                next_block_ctx.dev->name,
1503                                                next_block_ctx.dev_bytenr,
1504                                                mirror_num,
1505                                                next_block->logical_bytenr);
1506                                 }
1507                                 next_block->logical_bytenr = next_bytenr;
1508                                 next_block->mirror_num = mirror_num;
1509                         }
1510
1511                         l = btrfsic_block_link_lookup_or_add(state,
1512                                                              &next_block_ctx,
1513                                                              next_block, block,
1514                                                              generation);
1515                         btrfsic_release_block_ctx(&next_block_ctx);
1516                         if (NULL == l)
1517                                 return -1;
1518                 }
1519
1520                 next_bytenr += chunk_len;
1521                 num_bytes -= chunk_len;
1522         }
1523
1524         return 0;
1525 }
1526
1527 static int btrfsic_map_block(struct btrfsic_state *state, u64 bytenr, u32 len,
1528                              struct btrfsic_block_data_ctx *block_ctx_out,
1529                              int mirror_num)
1530 {
1531         struct btrfs_fs_info *fs_info = state->fs_info;
1532         int ret;
1533         u64 length;
1534         struct btrfs_bio *multi = NULL;
1535         struct btrfs_device *device;
1536
1537         length = len;
1538         ret = btrfs_map_block(fs_info, BTRFS_MAP_READ,
1539                               bytenr, &length, &multi, mirror_num);
1540
1541         if (ret) {
1542                 block_ctx_out->start = 0;
1543                 block_ctx_out->dev_bytenr = 0;
1544                 block_ctx_out->len = 0;
1545                 block_ctx_out->dev = NULL;
1546                 block_ctx_out->datav = NULL;
1547                 block_ctx_out->pagev = NULL;
1548                 block_ctx_out->mem_to_free = NULL;
1549
1550                 return ret;
1551         }
1552
1553         device = multi->stripes[0].dev;
1554         block_ctx_out->dev = btrfsic_dev_state_lookup(device->bdev->bd_dev);
1555         block_ctx_out->dev_bytenr = multi->stripes[0].physical;
1556         block_ctx_out->start = bytenr;
1557         block_ctx_out->len = len;
1558         block_ctx_out->datav = NULL;
1559         block_ctx_out->pagev = NULL;
1560         block_ctx_out->mem_to_free = NULL;
1561
1562         kfree(multi);
1563         if (NULL == block_ctx_out->dev) {
1564                 ret = -ENXIO;
1565                 pr_info("btrfsic: error, cannot lookup dev (#1)!\n");
1566         }
1567
1568         return ret;
1569 }
1570
1571 static void btrfsic_release_block_ctx(struct btrfsic_block_data_ctx *block_ctx)
1572 {
1573         if (block_ctx->mem_to_free) {
1574                 unsigned int num_pages;
1575
1576                 BUG_ON(!block_ctx->datav);
1577                 BUG_ON(!block_ctx->pagev);
1578                 num_pages = (block_ctx->len + (u64)PAGE_SIZE - 1) >>
1579                             PAGE_SHIFT;
1580                 while (num_pages > 0) {
1581                         num_pages--;
1582                         if (block_ctx->datav[num_pages]) {
1583                                 kunmap(block_ctx->pagev[num_pages]);
1584                                 block_ctx->datav[num_pages] = NULL;
1585                         }
1586                         if (block_ctx->pagev[num_pages]) {
1587                                 __free_page(block_ctx->pagev[num_pages]);
1588                                 block_ctx->pagev[num_pages] = NULL;
1589                         }
1590                 }
1591
1592                 kfree(block_ctx->mem_to_free);
1593                 block_ctx->mem_to_free = NULL;
1594                 block_ctx->pagev = NULL;
1595                 block_ctx->datav = NULL;
1596         }
1597 }
1598
1599 static int btrfsic_read_block(struct btrfsic_state *state,
1600                               struct btrfsic_block_data_ctx *block_ctx)
1601 {
1602         unsigned int num_pages;
1603         unsigned int i;
1604         u64 dev_bytenr;
1605         int ret;
1606
1607         BUG_ON(block_ctx->datav);
1608         BUG_ON(block_ctx->pagev);
1609         BUG_ON(block_ctx->mem_to_free);
1610         if (block_ctx->dev_bytenr & ((u64)PAGE_SIZE - 1)) {
1611                 pr_info("btrfsic: read_block() with unaligned bytenr %llu\n",
1612                        block_ctx->dev_bytenr);
1613                 return -1;
1614         }
1615
1616         num_pages = (block_ctx->len + (u64)PAGE_SIZE - 1) >>
1617                     PAGE_SHIFT;
1618         block_ctx->mem_to_free = kzalloc((sizeof(*block_ctx->datav) +
1619                                           sizeof(*block_ctx->pagev)) *
1620                                          num_pages, GFP_NOFS);
1621         if (!block_ctx->mem_to_free)
1622                 return -ENOMEM;
1623         block_ctx->datav = block_ctx->mem_to_free;
1624         block_ctx->pagev = (struct page **)(block_ctx->datav + num_pages);
1625         for (i = 0; i < num_pages; i++) {
1626                 block_ctx->pagev[i] = alloc_page(GFP_NOFS);
1627                 if (!block_ctx->pagev[i])
1628                         return -1;
1629         }
1630
1631         dev_bytenr = block_ctx->dev_bytenr;
1632         for (i = 0; i < num_pages;) {
1633                 struct bio *bio;
1634                 unsigned int j;
1635
1636                 bio = btrfs_io_bio_alloc(num_pages - i);
1637                 bio_set_dev(bio, block_ctx->dev->bdev);
1638                 bio->bi_iter.bi_sector = dev_bytenr >> 9;
1639                 bio_set_op_attrs(bio, REQ_OP_READ, 0);
1640
1641                 for (j = i; j < num_pages; j++) {
1642                         ret = bio_add_page(bio, block_ctx->pagev[j],
1643                                            PAGE_SIZE, 0);
1644                         if (PAGE_SIZE != ret)
1645                                 break;
1646                 }
1647                 if (j == i) {
1648                         pr_info("btrfsic: error, failed to add a single page!\n");
1649                         return -1;
1650                 }
1651                 if (submit_bio_wait(bio)) {
1652                         pr_info("btrfsic: read error at logical %llu dev %s!\n",
1653                                block_ctx->start, block_ctx->dev->name);
1654                         bio_put(bio);
1655                         return -1;
1656                 }
1657                 bio_put(bio);
1658                 dev_bytenr += (j - i) * PAGE_SIZE;
1659                 i = j;
1660         }
1661         for (i = 0; i < num_pages; i++)
1662                 block_ctx->datav[i] = kmap(block_ctx->pagev[i]);
1663
1664         return block_ctx->len;
1665 }
1666
1667 static void btrfsic_dump_database(struct btrfsic_state *state)
1668 {
1669         const struct btrfsic_block *b_all;
1670
1671         BUG_ON(NULL == state);
1672
1673         pr_info("all_blocks_list:\n");
1674         list_for_each_entry(b_all, &state->all_blocks_list, all_blocks_node) {
1675                 const struct btrfsic_block_link *l;
1676
1677                 pr_info("%c-block @%llu (%s/%llu/%d)\n",
1678                        btrfsic_get_block_type(state, b_all),
1679                        b_all->logical_bytenr, b_all->dev_state->name,
1680                        b_all->dev_bytenr, b_all->mirror_num);
1681
1682                 list_for_each_entry(l, &b_all->ref_to_list, node_ref_to) {
1683                         pr_info(" %c @%llu (%s/%llu/%d) refers %u* to %c @%llu (%s/%llu/%d)\n",
1684                                btrfsic_get_block_type(state, b_all),
1685                                b_all->logical_bytenr, b_all->dev_state->name,
1686                                b_all->dev_bytenr, b_all->mirror_num,
1687                                l->ref_cnt,
1688                                btrfsic_get_block_type(state, l->block_ref_to),
1689                                l->block_ref_to->logical_bytenr,
1690                                l->block_ref_to->dev_state->name,
1691                                l->block_ref_to->dev_bytenr,
1692                                l->block_ref_to->mirror_num);
1693                 }
1694
1695                 list_for_each_entry(l, &b_all->ref_from_list, node_ref_from) {
1696                         pr_info(" %c @%llu (%s/%llu/%d) is ref %u* from %c @%llu (%s/%llu/%d)\n",
1697                                btrfsic_get_block_type(state, b_all),
1698                                b_all->logical_bytenr, b_all->dev_state->name,
1699                                b_all->dev_bytenr, b_all->mirror_num,
1700                                l->ref_cnt,
1701                                btrfsic_get_block_type(state, l->block_ref_from),
1702                                l->block_ref_from->logical_bytenr,
1703                                l->block_ref_from->dev_state->name,
1704                                l->block_ref_from->dev_bytenr,
1705                                l->block_ref_from->mirror_num);
1706                 }
1707
1708                 pr_info("\n");
1709         }
1710 }
1711
1712 /*
1713  * Test whether the disk block contains a tree block (leaf or node)
1714  * (note that this test fails for the super block)
1715  */
1716 static int btrfsic_test_for_metadata(struct btrfsic_state *state,
1717                                      char **datav, unsigned int num_pages)
1718 {
1719         struct btrfs_fs_info *fs_info = state->fs_info;
1720         struct btrfs_header *h;
1721         u8 csum[BTRFS_CSUM_SIZE];
1722         u32 crc = ~(u32)0;
1723         unsigned int i;
1724
1725         if (num_pages * PAGE_SIZE < state->metablock_size)
1726                 return 1; /* not metadata */
1727         num_pages = state->metablock_size >> PAGE_SHIFT;
1728         h = (struct btrfs_header *)datav[0];
1729
1730         if (memcmp(h->fsid, fs_info->fsid, BTRFS_FSID_SIZE))
1731                 return 1;
1732
1733         for (i = 0; i < num_pages; i++) {
1734                 u8 *data = i ? datav[i] : (datav[i] + BTRFS_CSUM_SIZE);
1735                 size_t sublen = i ? PAGE_SIZE :
1736                                     (PAGE_SIZE - BTRFS_CSUM_SIZE);
1737
1738                 crc = btrfs_crc32c(crc, data, sublen);
1739         }
1740         btrfs_csum_final(crc, csum);
1741         if (memcmp(csum, h->csum, state->csum_size))
1742                 return 1;
1743
1744         return 0; /* is metadata */
1745 }
1746
1747 static void btrfsic_process_written_block(struct btrfsic_dev_state *dev_state,
1748                                           u64 dev_bytenr, char **mapped_datav,
1749                                           unsigned int num_pages,
1750                                           struct bio *bio, int *bio_is_patched,
1751                                           struct buffer_head *bh,
1752                                           int submit_bio_bh_rw)
1753 {
1754         int is_metadata;
1755         struct btrfsic_block *block;
1756         struct btrfsic_block_data_ctx block_ctx;
1757         int ret;
1758         struct btrfsic_state *state = dev_state->state;
1759         struct block_device *bdev = dev_state->bdev;
1760         unsigned int processed_len;
1761
1762         if (NULL != bio_is_patched)
1763                 *bio_is_patched = 0;
1764
1765 again:
1766         if (num_pages == 0)
1767                 return;
1768
1769         processed_len = 0;
1770         is_metadata = (0 == btrfsic_test_for_metadata(state, mapped_datav,
1771                                                       num_pages));
1772
1773         block = btrfsic_block_hashtable_lookup(bdev, dev_bytenr,
1774                                                &state->block_hashtable);
1775         if (NULL != block) {
1776                 u64 bytenr = 0;
1777                 struct btrfsic_block_link *l, *tmp;
1778
1779                 if (block->is_superblock) {
1780                         bytenr = btrfs_super_bytenr((struct btrfs_super_block *)
1781                                                     mapped_datav[0]);
1782                         if (num_pages * PAGE_SIZE <
1783                             BTRFS_SUPER_INFO_SIZE) {
1784                                 pr_info("btrfsic: cannot work with too short bios!\n");
1785                                 return;
1786                         }
1787                         is_metadata = 1;
1788                         BUG_ON(BTRFS_SUPER_INFO_SIZE & (PAGE_SIZE - 1));
1789                         processed_len = BTRFS_SUPER_INFO_SIZE;
1790                         if (state->print_mask &
1791                             BTRFSIC_PRINT_MASK_TREE_BEFORE_SB_WRITE) {
1792                                 pr_info("[before new superblock is written]:\n");
1793                                 btrfsic_dump_tree_sub(state, block, 0);
1794                         }
1795                 }
1796                 if (is_metadata) {
1797                         if (!block->is_superblock) {
1798                                 if (num_pages * PAGE_SIZE <
1799                                     state->metablock_size) {
1800                                         pr_info("btrfsic: cannot work with too short bios!\n");
1801                                         return;
1802                                 }
1803                                 processed_len = state->metablock_size;
1804                                 bytenr = btrfs_stack_header_bytenr(
1805                                                 (struct btrfs_header *)
1806                                                 mapped_datav[0]);
1807                                 btrfsic_cmp_log_and_dev_bytenr(state, bytenr,
1808                                                                dev_state,
1809                                                                dev_bytenr);
1810                         }
1811                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE) {
1812                                 if (block->logical_bytenr != bytenr &&
1813                                     !(!block->is_metadata &&
1814                                       block->logical_bytenr == 0))
1815                                         pr_info("Written block @%llu (%s/%llu/%d) found in hash table, %c, bytenr mismatch (!= stored %llu).\n",
1816                                                bytenr, dev_state->name,
1817                                                dev_bytenr,
1818                                                block->mirror_num,
1819                                                btrfsic_get_block_type(state,
1820                                                                       block),
1821                                                block->logical_bytenr);
1822                                 else
1823                                         pr_info("Written block @%llu (%s/%llu/%d) found in hash table, %c.\n",
1824                                                bytenr, dev_state->name,
1825                                                dev_bytenr, block->mirror_num,
1826                                                btrfsic_get_block_type(state,
1827                                                                       block));
1828                         }
1829                         block->logical_bytenr = bytenr;
1830                 } else {
1831                         if (num_pages * PAGE_SIZE <
1832                             state->datablock_size) {
1833                                 pr_info("btrfsic: cannot work with too short bios!\n");
1834                                 return;
1835                         }
1836                         processed_len = state->datablock_size;
1837                         bytenr = block->logical_bytenr;
1838                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1839                                 pr_info("Written block @%llu (%s/%llu/%d) found in hash table, %c.\n",
1840                                        bytenr, dev_state->name, dev_bytenr,
1841                                        block->mirror_num,
1842                                        btrfsic_get_block_type(state, block));
1843                 }
1844
1845                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1846                         pr_info("ref_to_list: %cE, ref_from_list: %cE\n",
1847                                list_empty(&block->ref_to_list) ? ' ' : '!',
1848                                list_empty(&block->ref_from_list) ? ' ' : '!');
1849                 if (btrfsic_is_block_ref_by_superblock(state, block, 0)) {
1850                         pr_info("btrfs: attempt to overwrite %c-block @%llu (%s/%llu/%d), old(gen=%llu, objectid=%llu, type=%d, offset=%llu), new(gen=%llu), which is referenced by most recent superblock (superblockgen=%llu)!\n",
1851                                btrfsic_get_block_type(state, block), bytenr,
1852                                dev_state->name, dev_bytenr, block->mirror_num,
1853                                block->generation,
1854                                btrfs_disk_key_objectid(&block->disk_key),
1855                                block->disk_key.type,
1856                                btrfs_disk_key_offset(&block->disk_key),
1857                                btrfs_stack_header_generation(
1858                                        (struct btrfs_header *) mapped_datav[0]),
1859                                state->max_superblock_generation);
1860                         btrfsic_dump_tree(state);
1861                 }
1862
1863                 if (!block->is_iodone && !block->never_written) {
1864                         pr_info("btrfs: attempt to overwrite %c-block @%llu (%s/%llu/%d), oldgen=%llu, newgen=%llu, which is not yet iodone!\n",
1865                                btrfsic_get_block_type(state, block), bytenr,
1866                                dev_state->name, dev_bytenr, block->mirror_num,
1867                                block->generation,
1868                                btrfs_stack_header_generation(
1869                                        (struct btrfs_header *)
1870                                        mapped_datav[0]));
1871                         /* it would not be safe to go on */
1872                         btrfsic_dump_tree(state);
1873                         goto continue_loop;
1874                 }
1875
1876                 /*
1877                  * Clear all references of this block. Do not free
1878                  * the block itself even if is not referenced anymore
1879                  * because it still carries valuable information
1880                  * like whether it was ever written and IO completed.
1881                  */
1882                 list_for_each_entry_safe(l, tmp, &block->ref_to_list,
1883                                          node_ref_to) {
1884                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
1885                                 btrfsic_print_rem_link(state, l);
1886                         l->ref_cnt--;
1887                         if (0 == l->ref_cnt) {
1888                                 list_del(&l->node_ref_to);
1889                                 list_del(&l->node_ref_from);
1890                                 btrfsic_block_link_hashtable_remove(l);
1891                                 btrfsic_block_link_free(l);
1892                         }
1893                 }
1894
1895                 block_ctx.dev = dev_state;
1896                 block_ctx.dev_bytenr = dev_bytenr;
1897                 block_ctx.start = bytenr;
1898                 block_ctx.len = processed_len;
1899                 block_ctx.pagev = NULL;
1900                 block_ctx.mem_to_free = NULL;
1901                 block_ctx.datav = mapped_datav;
1902
1903                 if (is_metadata || state->include_extent_data) {
1904                         block->never_written = 0;
1905                         block->iodone_w_error = 0;
1906                         if (NULL != bio) {
1907                                 block->is_iodone = 0;
1908                                 BUG_ON(NULL == bio_is_patched);
1909                                 if (!*bio_is_patched) {
1910                                         block->orig_bio_bh_private =
1911                                             bio->bi_private;
1912                                         block->orig_bio_bh_end_io.bio =
1913                                             bio->bi_end_io;
1914                                         block->next_in_same_bio = NULL;
1915                                         bio->bi_private = block;
1916                                         bio->bi_end_io = btrfsic_bio_end_io;
1917                                         *bio_is_patched = 1;
1918                                 } else {
1919                                         struct btrfsic_block *chained_block =
1920                                             (struct btrfsic_block *)
1921                                             bio->bi_private;
1922
1923                                         BUG_ON(NULL == chained_block);
1924                                         block->orig_bio_bh_private =
1925                                             chained_block->orig_bio_bh_private;
1926                                         block->orig_bio_bh_end_io.bio =
1927                                             chained_block->orig_bio_bh_end_io.
1928                                             bio;
1929                                         block->next_in_same_bio = chained_block;
1930                                         bio->bi_private = block;
1931                                 }
1932                         } else if (NULL != bh) {
1933                                 block->is_iodone = 0;
1934                                 block->orig_bio_bh_private = bh->b_private;
1935                                 block->orig_bio_bh_end_io.bh = bh->b_end_io;
1936                                 block->next_in_same_bio = NULL;
1937                                 bh->b_private = block;
1938                                 bh->b_end_io = btrfsic_bh_end_io;
1939                         } else {
1940                                 block->is_iodone = 1;
1941                                 block->orig_bio_bh_private = NULL;
1942                                 block->orig_bio_bh_end_io.bio = NULL;
1943                                 block->next_in_same_bio = NULL;
1944                         }
1945                 }
1946
1947                 block->flush_gen = dev_state->last_flush_gen + 1;
1948                 block->submit_bio_bh_rw = submit_bio_bh_rw;
1949                 if (is_metadata) {
1950                         block->logical_bytenr = bytenr;
1951                         block->is_metadata = 1;
1952                         if (block->is_superblock) {
1953                                 BUG_ON(PAGE_SIZE !=
1954                                        BTRFS_SUPER_INFO_SIZE);
1955                                 ret = btrfsic_process_written_superblock(
1956                                                 state,
1957                                                 block,
1958                                                 (struct btrfs_super_block *)
1959                                                 mapped_datav[0]);
1960                                 if (state->print_mask &
1961                                     BTRFSIC_PRINT_MASK_TREE_AFTER_SB_WRITE) {
1962                                         pr_info("[after new superblock is written]:\n");
1963                                         btrfsic_dump_tree_sub(state, block, 0);
1964                                 }
1965                         } else {
1966                                 block->mirror_num = 0;  /* unknown */
1967                                 ret = btrfsic_process_metablock(
1968                                                 state,
1969                                                 block,
1970                                                 &block_ctx,
1971                                                 0, 0);
1972                         }
1973                         if (ret)
1974                                 pr_info("btrfsic: btrfsic_process_metablock(root @%llu) failed!\n",
1975                                        dev_bytenr);
1976                 } else {
1977                         block->is_metadata = 0;
1978                         block->mirror_num = 0;  /* unknown */
1979                         block->generation = BTRFSIC_GENERATION_UNKNOWN;
1980                         if (!state->include_extent_data
1981                             && list_empty(&block->ref_from_list)) {
1982                                 /*
1983                                  * disk block is overwritten with extent
1984                                  * data (not meta data) and we are configured
1985                                  * to not include extent data: take the
1986                                  * chance and free the block's memory
1987                                  */
1988                                 btrfsic_block_hashtable_remove(block);
1989                                 list_del(&block->all_blocks_node);
1990                                 btrfsic_block_free(block);
1991                         }
1992                 }
1993                 btrfsic_release_block_ctx(&block_ctx);
1994         } else {
1995                 /* block has not been found in hash table */
1996                 u64 bytenr;
1997
1998                 if (!is_metadata) {
1999                         processed_len = state->datablock_size;
2000                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2001                                 pr_info("Written block (%s/%llu/?) !found in hash table, D.\n",
2002                                        dev_state->name, dev_bytenr);
2003                         if (!state->include_extent_data) {
2004                                 /* ignore that written D block */
2005                                 goto continue_loop;
2006                         }
2007
2008                         /* this is getting ugly for the
2009                          * include_extent_data case... */
2010                         bytenr = 0;     /* unknown */
2011                 } else {
2012                         processed_len = state->metablock_size;
2013                         bytenr = btrfs_stack_header_bytenr(
2014                                         (struct btrfs_header *)
2015                                         mapped_datav[0]);
2016                         btrfsic_cmp_log_and_dev_bytenr(state, bytenr, dev_state,
2017                                                        dev_bytenr);
2018                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2019                                 pr_info("Written block @%llu (%s/%llu/?) !found in hash table, M.\n",
2020                                        bytenr, dev_state->name, dev_bytenr);
2021                 }
2022
2023                 block_ctx.dev = dev_state;
2024                 block_ctx.dev_bytenr = dev_bytenr;
2025                 block_ctx.start = bytenr;
2026                 block_ctx.len = processed_len;
2027                 block_ctx.pagev = NULL;
2028                 block_ctx.mem_to_free = NULL;
2029                 block_ctx.datav = mapped_datav;
2030
2031                 block = btrfsic_block_alloc();
2032                 if (NULL == block) {
2033                         pr_info("btrfsic: error, kmalloc failed!\n");
2034                         btrfsic_release_block_ctx(&block_ctx);
2035                         goto continue_loop;
2036                 }
2037                 block->dev_state = dev_state;
2038                 block->dev_bytenr = dev_bytenr;
2039                 block->logical_bytenr = bytenr;
2040                 block->is_metadata = is_metadata;
2041                 block->never_written = 0;
2042                 block->iodone_w_error = 0;
2043                 block->mirror_num = 0;  /* unknown */
2044                 block->flush_gen = dev_state->last_flush_gen + 1;
2045                 block->submit_bio_bh_rw = submit_bio_bh_rw;
2046                 if (NULL != bio) {
2047                         block->is_iodone = 0;
2048                         BUG_ON(NULL == bio_is_patched);
2049                         if (!*bio_is_patched) {
2050                                 block->orig_bio_bh_private = bio->bi_private;
2051                                 block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2052                                 block->next_in_same_bio = NULL;
2053                                 bio->bi_private = block;
2054                                 bio->bi_end_io = btrfsic_bio_end_io;
2055                                 *bio_is_patched = 1;
2056                         } else {
2057                                 struct btrfsic_block *chained_block =
2058                                     (struct btrfsic_block *)
2059                                     bio->bi_private;
2060
2061                                 BUG_ON(NULL == chained_block);
2062                                 block->orig_bio_bh_private =
2063                                     chained_block->orig_bio_bh_private;
2064                                 block->orig_bio_bh_end_io.bio =
2065                                     chained_block->orig_bio_bh_end_io.bio;
2066                                 block->next_in_same_bio = chained_block;
2067                                 bio->bi_private = block;
2068                         }
2069                 } else if (NULL != bh) {
2070                         block->is_iodone = 0;
2071                         block->orig_bio_bh_private = bh->b_private;
2072                         block->orig_bio_bh_end_io.bh = bh->b_end_io;
2073                         block->next_in_same_bio = NULL;
2074                         bh->b_private = block;
2075                         bh->b_end_io = btrfsic_bh_end_io;
2076                 } else {
2077                         block->is_iodone = 1;
2078                         block->orig_bio_bh_private = NULL;
2079                         block->orig_bio_bh_end_io.bio = NULL;
2080                         block->next_in_same_bio = NULL;
2081                 }
2082                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2083                         pr_info("New written %c-block @%llu (%s/%llu/%d)\n",
2084                                is_metadata ? 'M' : 'D',
2085                                block->logical_bytenr, block->dev_state->name,
2086                                block->dev_bytenr, block->mirror_num);
2087                 list_add(&block->all_blocks_node, &state->all_blocks_list);
2088                 btrfsic_block_hashtable_add(block, &state->block_hashtable);
2089
2090                 if (is_metadata) {
2091                         ret = btrfsic_process_metablock(state, block,
2092                                                         &block_ctx, 0, 0);
2093                         if (ret)
2094                                 pr_info("btrfsic: process_metablock(root @%llu) failed!\n",
2095                                        dev_bytenr);
2096                 }
2097                 btrfsic_release_block_ctx(&block_ctx);
2098         }
2099
2100 continue_loop:
2101         BUG_ON(!processed_len);
2102         dev_bytenr += processed_len;
2103         mapped_datav += processed_len >> PAGE_SHIFT;
2104         num_pages -= processed_len >> PAGE_SHIFT;
2105         goto again;
2106 }
2107
2108 static void btrfsic_bio_end_io(struct bio *bp)
2109 {
2110         struct btrfsic_block *block = (struct btrfsic_block *)bp->bi_private;
2111         int iodone_w_error;
2112
2113         /* mutex is not held! This is not save if IO is not yet completed
2114          * on umount */
2115         iodone_w_error = 0;
2116         if (bp->bi_status)
2117                 iodone_w_error = 1;
2118
2119         BUG_ON(NULL == block);
2120         bp->bi_private = block->orig_bio_bh_private;
2121         bp->bi_end_io = block->orig_bio_bh_end_io.bio;
2122
2123         do {
2124                 struct btrfsic_block *next_block;
2125                 struct btrfsic_dev_state *const dev_state = block->dev_state;
2126
2127                 if ((dev_state->state->print_mask &
2128                      BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2129                         pr_info("bio_end_io(err=%d) for %c @%llu (%s/%llu/%d)\n",
2130                                bp->bi_status,
2131                                btrfsic_get_block_type(dev_state->state, block),
2132                                block->logical_bytenr, dev_state->name,
2133                                block->dev_bytenr, block->mirror_num);
2134                 next_block = block->next_in_same_bio;
2135                 block->iodone_w_error = iodone_w_error;
2136                 if (block->submit_bio_bh_rw & REQ_PREFLUSH) {
2137                         dev_state->last_flush_gen++;
2138                         if ((dev_state->state->print_mask &
2139                              BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2140                                 pr_info("bio_end_io() new %s flush_gen=%llu\n",
2141                                        dev_state->name,
2142                                        dev_state->last_flush_gen);
2143                 }
2144                 if (block->submit_bio_bh_rw & REQ_FUA)
2145                         block->flush_gen = 0; /* FUA completed means block is
2146                                                * on disk */
2147                 block->is_iodone = 1; /* for FLUSH, this releases the block */
2148                 block = next_block;
2149         } while (NULL != block);
2150
2151         bp->bi_end_io(bp);
2152 }
2153
2154 static void btrfsic_bh_end_io(struct buffer_head *bh, int uptodate)
2155 {
2156         struct btrfsic_block *block = (struct btrfsic_block *)bh->b_private;
2157         int iodone_w_error = !uptodate;
2158         struct btrfsic_dev_state *dev_state;
2159
2160         BUG_ON(NULL == block);
2161         dev_state = block->dev_state;
2162         if ((dev_state->state->print_mask & BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2163                 pr_info("bh_end_io(error=%d) for %c @%llu (%s/%llu/%d)\n",
2164                        iodone_w_error,
2165                        btrfsic_get_block_type(dev_state->state, block),
2166                        block->logical_bytenr, block->dev_state->name,
2167                        block->dev_bytenr, block->mirror_num);
2168
2169         block->iodone_w_error = iodone_w_error;
2170         if (block->submit_bio_bh_rw & REQ_PREFLUSH) {
2171                 dev_state->last_flush_gen++;
2172                 if ((dev_state->state->print_mask &
2173                      BTRFSIC_PRINT_MASK_END_IO_BIO_BH))
2174                         pr_info("bh_end_io() new %s flush_gen=%llu\n",
2175                                dev_state->name, dev_state->last_flush_gen);
2176         }
2177         if (block->submit_bio_bh_rw & REQ_FUA)
2178                 block->flush_gen = 0; /* FUA completed means block is on disk */
2179
2180         bh->b_private = block->orig_bio_bh_private;
2181         bh->b_end_io = block->orig_bio_bh_end_io.bh;
2182         block->is_iodone = 1; /* for FLUSH, this releases the block */
2183         bh->b_end_io(bh, uptodate);
2184 }
2185
2186 static int btrfsic_process_written_superblock(
2187                 struct btrfsic_state *state,
2188                 struct btrfsic_block *const superblock,
2189                 struct btrfs_super_block *const super_hdr)
2190 {
2191         struct btrfs_fs_info *fs_info = state->fs_info;
2192         int pass;
2193
2194         superblock->generation = btrfs_super_generation(super_hdr);
2195         if (!(superblock->generation > state->max_superblock_generation ||
2196               0 == state->max_superblock_generation)) {
2197                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2198                         pr_info("btrfsic: superblock @%llu (%s/%llu/%d) with old gen %llu <= %llu\n",
2199                                superblock->logical_bytenr,
2200                                superblock->dev_state->name,
2201                                superblock->dev_bytenr, superblock->mirror_num,
2202                                btrfs_super_generation(super_hdr),
2203                                state->max_superblock_generation);
2204         } else {
2205                 if (state->print_mask & BTRFSIC_PRINT_MASK_SUPERBLOCK_WRITE)
2206                         pr_info("btrfsic: got new superblock @%llu (%s/%llu/%d) with new gen %llu > %llu\n",
2207                                superblock->logical_bytenr,
2208                                superblock->dev_state->name,
2209                                superblock->dev_bytenr, superblock->mirror_num,
2210                                btrfs_super_generation(super_hdr),
2211                                state->max_superblock_generation);
2212
2213                 state->max_superblock_generation =
2214                     btrfs_super_generation(super_hdr);
2215                 state->latest_superblock = superblock;
2216         }
2217
2218         for (pass = 0; pass < 3; pass++) {
2219                 int ret;
2220                 u64 next_bytenr;
2221                 struct btrfsic_block *next_block;
2222                 struct btrfsic_block_data_ctx tmp_next_block_ctx;
2223                 struct btrfsic_block_link *l;
2224                 int num_copies;
2225                 int mirror_num;
2226                 const char *additional_string = NULL;
2227                 struct btrfs_disk_key tmp_disk_key = {0};
2228
2229                 btrfs_set_disk_key_objectid(&tmp_disk_key,
2230                                             BTRFS_ROOT_ITEM_KEY);
2231                 btrfs_set_disk_key_objectid(&tmp_disk_key, 0);
2232
2233                 switch (pass) {
2234                 case 0:
2235                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2236                                                     BTRFS_ROOT_TREE_OBJECTID);
2237                         additional_string = "root ";
2238                         next_bytenr = btrfs_super_root(super_hdr);
2239                         if (state->print_mask &
2240                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2241                                 pr_info("root@%llu\n", next_bytenr);
2242                         break;
2243                 case 1:
2244                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2245                                                     BTRFS_CHUNK_TREE_OBJECTID);
2246                         additional_string = "chunk ";
2247                         next_bytenr = btrfs_super_chunk_root(super_hdr);
2248                         if (state->print_mask &
2249                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2250                                 pr_info("chunk@%llu\n", next_bytenr);
2251                         break;
2252                 case 2:
2253                         btrfs_set_disk_key_objectid(&tmp_disk_key,
2254                                                     BTRFS_TREE_LOG_OBJECTID);
2255                         additional_string = "log ";
2256                         next_bytenr = btrfs_super_log_root(super_hdr);
2257                         if (0 == next_bytenr)
2258                                 continue;
2259                         if (state->print_mask &
2260                             BTRFSIC_PRINT_MASK_ROOT_CHUNK_LOG_TREE_LOCATION)
2261                                 pr_info("log@%llu\n", next_bytenr);
2262                         break;
2263                 }
2264
2265                 num_copies = btrfs_num_copies(fs_info, next_bytenr,
2266                                               BTRFS_SUPER_INFO_SIZE);
2267                 if (state->print_mask & BTRFSIC_PRINT_MASK_NUM_COPIES)
2268                         pr_info("num_copies(log_bytenr=%llu) = %d\n",
2269                                next_bytenr, num_copies);
2270                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2271                         int was_created;
2272
2273                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2274                                 pr_info("btrfsic_process_written_superblock(mirror_num=%d)\n", mirror_num);
2275                         ret = btrfsic_map_block(state, next_bytenr,
2276                                                 BTRFS_SUPER_INFO_SIZE,
2277                                                 &tmp_next_block_ctx,
2278                                                 mirror_num);
2279                         if (ret) {
2280                                 pr_info("btrfsic: btrfsic_map_block(@%llu, mirror=%d) failed!\n",
2281                                        next_bytenr, mirror_num);
2282                                 return -1;
2283                         }
2284
2285                         next_block = btrfsic_block_lookup_or_add(
2286                                         state,
2287                                         &tmp_next_block_ctx,
2288                                         additional_string,
2289                                         1, 0, 1,
2290                                         mirror_num,
2291                                         &was_created);
2292                         if (NULL == next_block) {
2293                                 pr_info("btrfsic: error, kmalloc failed!\n");
2294                                 btrfsic_release_block_ctx(&tmp_next_block_ctx);
2295                                 return -1;
2296                         }
2297
2298                         next_block->disk_key = tmp_disk_key;
2299                         if (was_created)
2300                                 next_block->generation =
2301                                     BTRFSIC_GENERATION_UNKNOWN;
2302                         l = btrfsic_block_link_lookup_or_add(
2303                                         state,
2304                                         &tmp_next_block_ctx,
2305                                         next_block,
2306                                         superblock,
2307                                         BTRFSIC_GENERATION_UNKNOWN);
2308                         btrfsic_release_block_ctx(&tmp_next_block_ctx);
2309                         if (NULL == l)
2310                                 return -1;
2311                 }
2312         }
2313
2314         if (WARN_ON(-1 == btrfsic_check_all_ref_blocks(state, superblock, 0)))
2315                 btrfsic_dump_tree(state);
2316
2317         return 0;
2318 }
2319
2320 static int btrfsic_check_all_ref_blocks(struct btrfsic_state *state,
2321                                         struct btrfsic_block *const block,
2322                                         int recursion_level)
2323 {
2324         const struct btrfsic_block_link *l;
2325         int ret = 0;
2326
2327         if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2328                 /*
2329                  * Note that this situation can happen and does not
2330                  * indicate an error in regular cases. It happens
2331                  * when disk blocks are freed and later reused.
2332                  * The check-integrity module is not aware of any
2333                  * block free operations, it just recognizes block
2334                  * write operations. Therefore it keeps the linkage
2335                  * information for a block until a block is
2336                  * rewritten. This can temporarily cause incorrect
2337                  * and even circular linkage informations. This
2338                  * causes no harm unless such blocks are referenced
2339                  * by the most recent super block.
2340                  */
2341                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2342                         pr_info("btrfsic: abort cyclic linkage (case 1).\n");
2343
2344                 return ret;
2345         }
2346
2347         /*
2348          * This algorithm is recursive because the amount of used stack
2349          * space is very small and the max recursion depth is limited.
2350          */
2351         list_for_each_entry(l, &block->ref_to_list, node_ref_to) {
2352                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2353                         pr_info("rl=%d, %c @%llu (%s/%llu/%d) %u* refers to %c @%llu (%s/%llu/%d)\n",
2354                                recursion_level,
2355                                btrfsic_get_block_type(state, block),
2356                                block->logical_bytenr, block->dev_state->name,
2357                                block->dev_bytenr, block->mirror_num,
2358                                l->ref_cnt,
2359                                btrfsic_get_block_type(state, l->block_ref_to),
2360                                l->block_ref_to->logical_bytenr,
2361                                l->block_ref_to->dev_state->name,
2362                                l->block_ref_to->dev_bytenr,
2363                                l->block_ref_to->mirror_num);
2364                 if (l->block_ref_to->never_written) {
2365                         pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) which is never written!\n",
2366                                btrfsic_get_block_type(state, l->block_ref_to),
2367                                l->block_ref_to->logical_bytenr,
2368                                l->block_ref_to->dev_state->name,
2369                                l->block_ref_to->dev_bytenr,
2370                                l->block_ref_to->mirror_num);
2371                         ret = -1;
2372                 } else if (!l->block_ref_to->is_iodone) {
2373                         pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) which is not yet iodone!\n",
2374                                btrfsic_get_block_type(state, l->block_ref_to),
2375                                l->block_ref_to->logical_bytenr,
2376                                l->block_ref_to->dev_state->name,
2377                                l->block_ref_to->dev_bytenr,
2378                                l->block_ref_to->mirror_num);
2379                         ret = -1;
2380                 } else if (l->block_ref_to->iodone_w_error) {
2381                         pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) which has write error!\n",
2382                                btrfsic_get_block_type(state, l->block_ref_to),
2383                                l->block_ref_to->logical_bytenr,
2384                                l->block_ref_to->dev_state->name,
2385                                l->block_ref_to->dev_bytenr,
2386                                l->block_ref_to->mirror_num);
2387                         ret = -1;
2388                 } else if (l->parent_generation !=
2389                            l->block_ref_to->generation &&
2390                            BTRFSIC_GENERATION_UNKNOWN !=
2391                            l->parent_generation &&
2392                            BTRFSIC_GENERATION_UNKNOWN !=
2393                            l->block_ref_to->generation) {
2394                         pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) with generation %llu != parent generation %llu!\n",
2395                                btrfsic_get_block_type(state, l->block_ref_to),
2396                                l->block_ref_to->logical_bytenr,
2397                                l->block_ref_to->dev_state->name,
2398                                l->block_ref_to->dev_bytenr,
2399                                l->block_ref_to->mirror_num,
2400                                l->block_ref_to->generation,
2401                                l->parent_generation);
2402                         ret = -1;
2403                 } else if (l->block_ref_to->flush_gen >
2404                            l->block_ref_to->dev_state->last_flush_gen) {
2405                         pr_info("btrfs: attempt to write superblock which references block %c @%llu (%s/%llu/%d) which is not flushed out of disk's write cache (block flush_gen=%llu, dev->flush_gen=%llu)!\n",
2406                                btrfsic_get_block_type(state, l->block_ref_to),
2407                                l->block_ref_to->logical_bytenr,
2408                                l->block_ref_to->dev_state->name,
2409                                l->block_ref_to->dev_bytenr,
2410                                l->block_ref_to->mirror_num, block->flush_gen,
2411                                l->block_ref_to->dev_state->last_flush_gen);
2412                         ret = -1;
2413                 } else if (-1 == btrfsic_check_all_ref_blocks(state,
2414                                                               l->block_ref_to,
2415                                                               recursion_level +
2416                                                               1)) {
2417                         ret = -1;
2418                 }
2419         }
2420
2421         return ret;
2422 }
2423
2424 static int btrfsic_is_block_ref_by_superblock(
2425                 const struct btrfsic_state *state,
2426                 const struct btrfsic_block *block,
2427                 int recursion_level)
2428 {
2429         const struct btrfsic_block_link *l;
2430
2431         if (recursion_level >= 3 + BTRFS_MAX_LEVEL) {
2432                 /* refer to comment at "abort cyclic linkage (case 1)" */
2433                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2434                         pr_info("btrfsic: abort cyclic linkage (case 2).\n");
2435
2436                 return 0;
2437         }
2438
2439         /*
2440          * This algorithm is recursive because the amount of used stack space
2441          * is very small and the max recursion depth is limited.
2442          */
2443         list_for_each_entry(l, &block->ref_from_list, node_ref_from) {
2444                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2445                         pr_info("rl=%d, %c @%llu (%s/%llu/%d) is ref %u* from %c @%llu (%s/%llu/%d)\n",
2446                                recursion_level,
2447                                btrfsic_get_block_type(state, block),
2448                                block->logical_bytenr, block->dev_state->name,
2449                                block->dev_bytenr, block->mirror_num,
2450                                l->ref_cnt,
2451                                btrfsic_get_block_type(state, l->block_ref_from),
2452                                l->block_ref_from->logical_bytenr,
2453                                l->block_ref_from->dev_state->name,
2454                                l->block_ref_from->dev_bytenr,
2455                                l->block_ref_from->mirror_num);
2456                 if (l->block_ref_from->is_superblock &&
2457                     state->latest_superblock->dev_bytenr ==
2458                     l->block_ref_from->dev_bytenr &&
2459                     state->latest_superblock->dev_state->bdev ==
2460                     l->block_ref_from->dev_state->bdev)
2461                         return 1;
2462                 else if (btrfsic_is_block_ref_by_superblock(state,
2463                                                             l->block_ref_from,
2464                                                             recursion_level +
2465                                                             1))
2466                         return 1;
2467         }
2468
2469         return 0;
2470 }
2471
2472 static void btrfsic_print_add_link(const struct btrfsic_state *state,
2473                                    const struct btrfsic_block_link *l)
2474 {
2475         pr_info("Add %u* link from %c @%llu (%s/%llu/%d) to %c @%llu (%s/%llu/%d).\n",
2476                l->ref_cnt,
2477                btrfsic_get_block_type(state, l->block_ref_from),
2478                l->block_ref_from->logical_bytenr,
2479                l->block_ref_from->dev_state->name,
2480                l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
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, l->block_ref_to->dev_bytenr,
2484                l->block_ref_to->mirror_num);
2485 }
2486
2487 static void btrfsic_print_rem_link(const struct btrfsic_state *state,
2488                                    const struct btrfsic_block_link *l)
2489 {
2490         pr_info("Rem %u* link from %c @%llu (%s/%llu/%d) to %c @%llu (%s/%llu/%d).\n",
2491                l->ref_cnt,
2492                btrfsic_get_block_type(state, l->block_ref_from),
2493                l->block_ref_from->logical_bytenr,
2494                l->block_ref_from->dev_state->name,
2495                l->block_ref_from->dev_bytenr, l->block_ref_from->mirror_num,
2496                btrfsic_get_block_type(state, l->block_ref_to),
2497                l->block_ref_to->logical_bytenr,
2498                l->block_ref_to->dev_state->name, l->block_ref_to->dev_bytenr,
2499                l->block_ref_to->mirror_num);
2500 }
2501
2502 static char btrfsic_get_block_type(const struct btrfsic_state *state,
2503                                    const struct btrfsic_block *block)
2504 {
2505         if (block->is_superblock &&
2506             state->latest_superblock->dev_bytenr == block->dev_bytenr &&
2507             state->latest_superblock->dev_state->bdev == block->dev_state->bdev)
2508                 return 'S';
2509         else if (block->is_superblock)
2510                 return 's';
2511         else if (block->is_metadata)
2512                 return 'M';
2513         else
2514                 return 'D';
2515 }
2516
2517 static void btrfsic_dump_tree(const struct btrfsic_state *state)
2518 {
2519         btrfsic_dump_tree_sub(state, state->latest_superblock, 0);
2520 }
2521
2522 static void btrfsic_dump_tree_sub(const struct btrfsic_state *state,
2523                                   const struct btrfsic_block *block,
2524                                   int indent_level)
2525 {
2526         const struct btrfsic_block_link *l;
2527         int indent_add;
2528         static char buf[80];
2529         int cursor_position;
2530
2531         /*
2532          * Should better fill an on-stack buffer with a complete line and
2533          * dump it at once when it is time to print a newline character.
2534          */
2535
2536         /*
2537          * This algorithm is recursive because the amount of used stack space
2538          * is very small and the max recursion depth is limited.
2539          */
2540         indent_add = sprintf(buf, "%c-%llu(%s/%llu/%u)",
2541                              btrfsic_get_block_type(state, block),
2542                              block->logical_bytenr, block->dev_state->name,
2543                              block->dev_bytenr, block->mirror_num);
2544         if (indent_level + indent_add > BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2545                 printk("[...]\n");
2546                 return;
2547         }
2548         printk(buf);
2549         indent_level += indent_add;
2550         if (list_empty(&block->ref_to_list)) {
2551                 printk("\n");
2552                 return;
2553         }
2554         if (block->mirror_num > 1 &&
2555             !(state->print_mask & BTRFSIC_PRINT_MASK_TREE_WITH_ALL_MIRRORS)) {
2556                 printk(" [...]\n");
2557                 return;
2558         }
2559
2560         cursor_position = indent_level;
2561         list_for_each_entry(l, &block->ref_to_list, node_ref_to) {
2562                 while (cursor_position < indent_level) {
2563                         printk(" ");
2564                         cursor_position++;
2565                 }
2566                 if (l->ref_cnt > 1)
2567                         indent_add = sprintf(buf, " %d*--> ", l->ref_cnt);
2568                 else
2569                         indent_add = sprintf(buf, " --> ");
2570                 if (indent_level + indent_add >
2571                     BTRFSIC_TREE_DUMP_MAX_INDENT_LEVEL) {
2572                         printk("[...]\n");
2573                         cursor_position = 0;
2574                         continue;
2575                 }
2576
2577                 printk(buf);
2578
2579                 btrfsic_dump_tree_sub(state, l->block_ref_to,
2580                                       indent_level + indent_add);
2581                 cursor_position = 0;
2582         }
2583 }
2584
2585 static struct btrfsic_block_link *btrfsic_block_link_lookup_or_add(
2586                 struct btrfsic_state *state,
2587                 struct btrfsic_block_data_ctx *next_block_ctx,
2588                 struct btrfsic_block *next_block,
2589                 struct btrfsic_block *from_block,
2590                 u64 parent_generation)
2591 {
2592         struct btrfsic_block_link *l;
2593
2594         l = btrfsic_block_link_hashtable_lookup(next_block_ctx->dev->bdev,
2595                                                 next_block_ctx->dev_bytenr,
2596                                                 from_block->dev_state->bdev,
2597                                                 from_block->dev_bytenr,
2598                                                 &state->block_link_hashtable);
2599         if (NULL == l) {
2600                 l = btrfsic_block_link_alloc();
2601                 if (NULL == l) {
2602                         pr_info("btrfsic: error, kmalloc failed!\n");
2603                         return NULL;
2604                 }
2605
2606                 l->block_ref_to = next_block;
2607                 l->block_ref_from = from_block;
2608                 l->ref_cnt = 1;
2609                 l->parent_generation = parent_generation;
2610
2611                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2612                         btrfsic_print_add_link(state, l);
2613
2614                 list_add(&l->node_ref_to, &from_block->ref_to_list);
2615                 list_add(&l->node_ref_from, &next_block->ref_from_list);
2616
2617                 btrfsic_block_link_hashtable_add(l,
2618                                                  &state->block_link_hashtable);
2619         } else {
2620                 l->ref_cnt++;
2621                 l->parent_generation = parent_generation;
2622                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2623                         btrfsic_print_add_link(state, l);
2624         }
2625
2626         return l;
2627 }
2628
2629 static struct btrfsic_block *btrfsic_block_lookup_or_add(
2630                 struct btrfsic_state *state,
2631                 struct btrfsic_block_data_ctx *block_ctx,
2632                 const char *additional_string,
2633                 int is_metadata,
2634                 int is_iodone,
2635                 int never_written,
2636                 int mirror_num,
2637                 int *was_created)
2638 {
2639         struct btrfsic_block *block;
2640
2641         block = btrfsic_block_hashtable_lookup(block_ctx->dev->bdev,
2642                                                block_ctx->dev_bytenr,
2643                                                &state->block_hashtable);
2644         if (NULL == block) {
2645                 struct btrfsic_dev_state *dev_state;
2646
2647                 block = btrfsic_block_alloc();
2648                 if (NULL == block) {
2649                         pr_info("btrfsic: error, kmalloc failed!\n");
2650                         return NULL;
2651                 }
2652                 dev_state = btrfsic_dev_state_lookup(block_ctx->dev->bdev->bd_dev);
2653                 if (NULL == dev_state) {
2654                         pr_info("btrfsic: error, lookup dev_state failed!\n");
2655                         btrfsic_block_free(block);
2656                         return NULL;
2657                 }
2658                 block->dev_state = dev_state;
2659                 block->dev_bytenr = block_ctx->dev_bytenr;
2660                 block->logical_bytenr = block_ctx->start;
2661                 block->is_metadata = is_metadata;
2662                 block->is_iodone = is_iodone;
2663                 block->never_written = never_written;
2664                 block->mirror_num = mirror_num;
2665                 if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
2666                         pr_info("New %s%c-block @%llu (%s/%llu/%d)\n",
2667                                additional_string,
2668                                btrfsic_get_block_type(state, block),
2669                                block->logical_bytenr, dev_state->name,
2670                                block->dev_bytenr, mirror_num);
2671                 list_add(&block->all_blocks_node, &state->all_blocks_list);
2672                 btrfsic_block_hashtable_add(block, &state->block_hashtable);
2673                 if (NULL != was_created)
2674                         *was_created = 1;
2675         } else {
2676                 if (NULL != was_created)
2677                         *was_created = 0;
2678         }
2679
2680         return block;
2681 }
2682
2683 static void btrfsic_cmp_log_and_dev_bytenr(struct btrfsic_state *state,
2684                                            u64 bytenr,
2685                                            struct btrfsic_dev_state *dev_state,
2686                                            u64 dev_bytenr)
2687 {
2688         struct btrfs_fs_info *fs_info = state->fs_info;
2689         struct btrfsic_block_data_ctx block_ctx;
2690         int num_copies;
2691         int mirror_num;
2692         int match = 0;
2693         int ret;
2694
2695         num_copies = btrfs_num_copies(fs_info, bytenr, state->metablock_size);
2696
2697         for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2698                 ret = btrfsic_map_block(state, bytenr, state->metablock_size,
2699                                         &block_ctx, mirror_num);
2700                 if (ret) {
2701                         pr_info("btrfsic: btrfsic_map_block(logical @%llu, mirror %d) failed!\n",
2702                                bytenr, mirror_num);
2703                         continue;
2704                 }
2705
2706                 if (dev_state->bdev == block_ctx.dev->bdev &&
2707                     dev_bytenr == block_ctx.dev_bytenr) {
2708                         match++;
2709                         btrfsic_release_block_ctx(&block_ctx);
2710                         break;
2711                 }
2712                 btrfsic_release_block_ctx(&block_ctx);
2713         }
2714
2715         if (WARN_ON(!match)) {
2716                 pr_info("btrfs: attempt to write M-block which contains logical bytenr that doesn't map to dev+physical bytenr of submit_bio, buffer->log_bytenr=%llu, submit_bio(bdev=%s, phys_bytenr=%llu)!\n",
2717                        bytenr, dev_state->name, dev_bytenr);
2718                 for (mirror_num = 1; mirror_num <= num_copies; mirror_num++) {
2719                         ret = btrfsic_map_block(state, bytenr,
2720                                                 state->metablock_size,
2721                                                 &block_ctx, mirror_num);
2722                         if (ret)
2723                                 continue;
2724
2725                         pr_info("Read logical bytenr @%llu maps to (%s/%llu/%d)\n",
2726                                bytenr, block_ctx.dev->name,
2727                                block_ctx.dev_bytenr, mirror_num);
2728                 }
2729         }
2730 }
2731
2732 static struct btrfsic_dev_state *btrfsic_dev_state_lookup(dev_t dev)
2733 {
2734         return btrfsic_dev_state_hashtable_lookup(dev,
2735                                                   &btrfsic_dev_state_hashtable);
2736 }
2737
2738 int btrfsic_submit_bh(int op, int op_flags, struct buffer_head *bh)
2739 {
2740         struct btrfsic_dev_state *dev_state;
2741
2742         if (!btrfsic_is_initialized)
2743                 return submit_bh(op, op_flags, bh);
2744
2745         mutex_lock(&btrfsic_mutex);
2746         /* since btrfsic_submit_bh() might also be called before
2747          * btrfsic_mount(), this might return NULL */
2748         dev_state = btrfsic_dev_state_lookup(bh->b_bdev->bd_dev);
2749
2750         /* Only called to write the superblock (incl. FLUSH/FUA) */
2751         if (NULL != dev_state &&
2752             (op == REQ_OP_WRITE) && bh->b_size > 0) {
2753                 u64 dev_bytenr;
2754
2755                 dev_bytenr = BTRFS_BDEV_BLOCKSIZE * bh->b_blocknr;
2756                 if (dev_state->state->print_mask &
2757                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2758                         pr_info("submit_bh(op=0x%x,0x%x, blocknr=%llu (bytenr %llu), size=%zu, data=%p, bdev=%p)\n",
2759                                op, op_flags, (unsigned long long)bh->b_blocknr,
2760                                dev_bytenr, bh->b_size, bh->b_data, bh->b_bdev);
2761                 btrfsic_process_written_block(dev_state, dev_bytenr,
2762                                               &bh->b_data, 1, NULL,
2763                                               NULL, bh, op_flags);
2764         } else if (NULL != dev_state && (op_flags & REQ_PREFLUSH)) {
2765                 if (dev_state->state->print_mask &
2766                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2767                         pr_info("submit_bh(op=0x%x,0x%x FLUSH, bdev=%p)\n",
2768                                op, op_flags, bh->b_bdev);
2769                 if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
2770                         if ((dev_state->state->print_mask &
2771                              (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2772                               BTRFSIC_PRINT_MASK_VERBOSE)))
2773                                 pr_info("btrfsic_submit_bh(%s) with FLUSH but dummy block already in use (ignored)!\n",
2774                                        dev_state->name);
2775                 } else {
2776                         struct btrfsic_block *const block =
2777                                 &dev_state->dummy_block_for_bio_bh_flush;
2778
2779                         block->is_iodone = 0;
2780                         block->never_written = 0;
2781                         block->iodone_w_error = 0;
2782                         block->flush_gen = dev_state->last_flush_gen + 1;
2783                         block->submit_bio_bh_rw = op_flags;
2784                         block->orig_bio_bh_private = bh->b_private;
2785                         block->orig_bio_bh_end_io.bh = bh->b_end_io;
2786                         block->next_in_same_bio = NULL;
2787                         bh->b_private = block;
2788                         bh->b_end_io = btrfsic_bh_end_io;
2789                 }
2790         }
2791         mutex_unlock(&btrfsic_mutex);
2792         return submit_bh(op, op_flags, bh);
2793 }
2794
2795 static void __btrfsic_submit_bio(struct bio *bio)
2796 {
2797         struct btrfsic_dev_state *dev_state;
2798
2799         if (!btrfsic_is_initialized)
2800                 return;
2801
2802         mutex_lock(&btrfsic_mutex);
2803         /* since btrfsic_submit_bio() is also called before
2804          * btrfsic_mount(), this might return NULL */
2805         dev_state = btrfsic_dev_state_lookup(bio_dev(bio));
2806         if (NULL != dev_state &&
2807             (bio_op(bio) == REQ_OP_WRITE) && bio_has_data(bio)) {
2808                 unsigned int i = 0;
2809                 u64 dev_bytenr;
2810                 u64 cur_bytenr;
2811                 struct bio_vec bvec;
2812                 struct bvec_iter iter;
2813                 int bio_is_patched;
2814                 char **mapped_datav;
2815                 unsigned int segs = bio_segments(bio);
2816
2817                 dev_bytenr = 512 * bio->bi_iter.bi_sector;
2818                 bio_is_patched = 0;
2819                 if (dev_state->state->print_mask &
2820                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2821                         pr_info("submit_bio(rw=%d,0x%x, bi_vcnt=%u, bi_sector=%llu (bytenr %llu), bi_disk=%p)\n",
2822                                bio_op(bio), bio->bi_opf, segs,
2823                                (unsigned long long)bio->bi_iter.bi_sector,
2824                                dev_bytenr, bio->bi_disk);
2825
2826                 mapped_datav = kmalloc_array(segs,
2827                                              sizeof(*mapped_datav), GFP_NOFS);
2828                 if (!mapped_datav)
2829                         goto leave;
2830                 cur_bytenr = dev_bytenr;
2831
2832                 bio_for_each_segment(bvec, bio, iter) {
2833                         BUG_ON(bvec.bv_len != PAGE_SIZE);
2834                         mapped_datav[i] = kmap(bvec.bv_page);
2835                         i++;
2836
2837                         if (dev_state->state->print_mask &
2838                             BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH_VERBOSE)
2839                                 pr_info("#%u: bytenr=%llu, len=%u, offset=%u\n",
2840                                        i, cur_bytenr, bvec.bv_len, bvec.bv_offset);
2841                         cur_bytenr += bvec.bv_len;
2842                 }
2843                 btrfsic_process_written_block(dev_state, dev_bytenr,
2844                                               mapped_datav, segs,
2845                                               bio, &bio_is_patched,
2846                                               NULL, bio->bi_opf);
2847                 bio_for_each_segment(bvec, bio, iter)
2848                         kunmap(bvec.bv_page);
2849                 kfree(mapped_datav);
2850         } else if (NULL != dev_state && (bio->bi_opf & REQ_PREFLUSH)) {
2851                 if (dev_state->state->print_mask &
2852                     BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
2853                         pr_info("submit_bio(rw=%d,0x%x FLUSH, disk=%p)\n",
2854                                bio_op(bio), bio->bi_opf, bio->bi_disk);
2855                 if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
2856                         if ((dev_state->state->print_mask &
2857                              (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
2858                               BTRFSIC_PRINT_MASK_VERBOSE)))
2859                                 pr_info("btrfsic_submit_bio(%s) with FLUSH but dummy block already in use (ignored)!\n",
2860                                        dev_state->name);
2861                 } else {
2862                         struct btrfsic_block *const block =
2863                                 &dev_state->dummy_block_for_bio_bh_flush;
2864
2865                         block->is_iodone = 0;
2866                         block->never_written = 0;
2867                         block->iodone_w_error = 0;
2868                         block->flush_gen = dev_state->last_flush_gen + 1;
2869                         block->submit_bio_bh_rw = bio->bi_opf;
2870                         block->orig_bio_bh_private = bio->bi_private;
2871                         block->orig_bio_bh_end_io.bio = bio->bi_end_io;
2872                         block->next_in_same_bio = NULL;
2873                         bio->bi_private = block;
2874                         bio->bi_end_io = btrfsic_bio_end_io;
2875                 }
2876         }
2877 leave:
2878         mutex_unlock(&btrfsic_mutex);
2879 }
2880
2881 void btrfsic_submit_bio(struct bio *bio)
2882 {
2883         __btrfsic_submit_bio(bio);
2884         submit_bio(bio);
2885 }
2886
2887 int btrfsic_submit_bio_wait(struct bio *bio)
2888 {
2889         __btrfsic_submit_bio(bio);
2890         return submit_bio_wait(bio);
2891 }
2892
2893 int btrfsic_mount(struct btrfs_fs_info *fs_info,
2894                   struct btrfs_fs_devices *fs_devices,
2895                   int including_extent_data, u32 print_mask)
2896 {
2897         int ret;
2898         struct btrfsic_state *state;
2899         struct list_head *dev_head = &fs_devices->devices;
2900         struct btrfs_device *device;
2901
2902         if (fs_info->nodesize & ((u64)PAGE_SIZE - 1)) {
2903                 pr_info("btrfsic: cannot handle nodesize %d not being a multiple of PAGE_SIZE %ld!\n",
2904                        fs_info->nodesize, PAGE_SIZE);
2905                 return -1;
2906         }
2907         if (fs_info->sectorsize & ((u64)PAGE_SIZE - 1)) {
2908                 pr_info("btrfsic: cannot handle sectorsize %d not being a multiple of PAGE_SIZE %ld!\n",
2909                        fs_info->sectorsize, PAGE_SIZE);
2910                 return -1;
2911         }
2912         state = kvzalloc(sizeof(*state), GFP_KERNEL);
2913         if (!state) {
2914                 pr_info("btrfs check-integrity: allocation failed!\n");
2915                 return -1;
2916         }
2917
2918         if (!btrfsic_is_initialized) {
2919                 mutex_init(&btrfsic_mutex);
2920                 btrfsic_dev_state_hashtable_init(&btrfsic_dev_state_hashtable);
2921                 btrfsic_is_initialized = 1;
2922         }
2923         mutex_lock(&btrfsic_mutex);
2924         state->fs_info = fs_info;
2925         state->print_mask = print_mask;
2926         state->include_extent_data = including_extent_data;
2927         state->csum_size = 0;
2928         state->metablock_size = fs_info->nodesize;
2929         state->datablock_size = fs_info->sectorsize;
2930         INIT_LIST_HEAD(&state->all_blocks_list);
2931         btrfsic_block_hashtable_init(&state->block_hashtable);
2932         btrfsic_block_link_hashtable_init(&state->block_link_hashtable);
2933         state->max_superblock_generation = 0;
2934         state->latest_superblock = NULL;
2935
2936         list_for_each_entry(device, dev_head, dev_list) {
2937                 struct btrfsic_dev_state *ds;
2938                 const char *p;
2939
2940                 if (!device->bdev || !device->name)
2941                         continue;
2942
2943                 ds = btrfsic_dev_state_alloc();
2944                 if (NULL == ds) {
2945                         pr_info("btrfs check-integrity: kmalloc() failed!\n");
2946                         mutex_unlock(&btrfsic_mutex);
2947                         return -1;
2948                 }
2949                 ds->bdev = device->bdev;
2950                 ds->state = state;
2951                 bdevname(ds->bdev, ds->name);
2952                 ds->name[BDEVNAME_SIZE - 1] = '\0';
2953                 p = kbasename(ds->name);
2954                 strlcpy(ds->name, p, sizeof(ds->name));
2955                 btrfsic_dev_state_hashtable_add(ds,
2956                                                 &btrfsic_dev_state_hashtable);
2957         }
2958
2959         ret = btrfsic_process_superblock(state, fs_devices);
2960         if (0 != ret) {
2961                 mutex_unlock(&btrfsic_mutex);
2962                 btrfsic_unmount(fs_devices);
2963                 return ret;
2964         }
2965
2966         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_DATABASE)
2967                 btrfsic_dump_database(state);
2968         if (state->print_mask & BTRFSIC_PRINT_MASK_INITIAL_TREE)
2969                 btrfsic_dump_tree(state);
2970
2971         mutex_unlock(&btrfsic_mutex);
2972         return 0;
2973 }
2974
2975 void btrfsic_unmount(struct btrfs_fs_devices *fs_devices)
2976 {
2977         struct btrfsic_block *b_all, *tmp_all;
2978         struct btrfsic_state *state;
2979         struct list_head *dev_head = &fs_devices->devices;
2980         struct btrfs_device *device;
2981
2982         if (!btrfsic_is_initialized)
2983                 return;
2984
2985         mutex_lock(&btrfsic_mutex);
2986
2987         state = NULL;
2988         list_for_each_entry(device, dev_head, dev_list) {
2989                 struct btrfsic_dev_state *ds;
2990
2991                 if (!device->bdev || !device->name)
2992                         continue;
2993
2994                 ds = btrfsic_dev_state_hashtable_lookup(
2995                                 device->bdev->bd_dev,
2996                                 &btrfsic_dev_state_hashtable);
2997                 if (NULL != ds) {
2998                         state = ds->state;
2999                         btrfsic_dev_state_hashtable_remove(ds);
3000                         btrfsic_dev_state_free(ds);
3001                 }
3002         }
3003
3004         if (NULL == state) {
3005                 pr_info("btrfsic: error, cannot find state information on umount!\n");
3006                 mutex_unlock(&btrfsic_mutex);
3007                 return;
3008         }
3009
3010         /*
3011          * Don't care about keeping the lists' state up to date,
3012          * just free all memory that was allocated dynamically.
3013          * Free the blocks and the block_links.
3014          */
3015         list_for_each_entry_safe(b_all, tmp_all, &state->all_blocks_list,
3016                                  all_blocks_node) {
3017                 struct btrfsic_block_link *l, *tmp;
3018
3019                 list_for_each_entry_safe(l, tmp, &b_all->ref_to_list,
3020                                          node_ref_to) {
3021                         if (state->print_mask & BTRFSIC_PRINT_MASK_VERBOSE)
3022                                 btrfsic_print_rem_link(state, l);
3023
3024                         l->ref_cnt--;
3025                         if (0 == l->ref_cnt)
3026                                 btrfsic_block_link_free(l);
3027                 }
3028
3029                 if (b_all->is_iodone || b_all->never_written)
3030                         btrfsic_block_free(b_all);
3031                 else
3032                         pr_info("btrfs: attempt to free %c-block @%llu (%s/%llu/%d) on umount which is not yet iodone!\n",
3033                                btrfsic_get_block_type(state, b_all),
3034                                b_all->logical_bytenr, b_all->dev_state->name,
3035                                b_all->dev_bytenr, b_all->mirror_num);
3036         }
3037
3038         mutex_unlock(&btrfsic_mutex);
3039
3040         kvfree(state);
3041 }